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Sample records for activated ester terminated

  1. Anticholinesterase activity of fluorochloronitroacetic acid esters

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, Yu.Ya.; Brel, V.K. Martynov, I.V.

    1984-11-01

    Results are presented from pharmacologic and biochemical experiments leading to the conclusion that fluorochloronitroacetic acid esters have anticholinesterase activity. Since the esters caused muscular weakness in mice, experiments were performed on isolated tissue preparation. The biochemical experiments consisted of finding the biomolecular constants of irreversible inhibition of acetylcholinesterase by the esters, using acetylcholinesterase from human erythrocytes, as well as horse serum cholinesterase. The ethyl and n-propyl esters of halogen nitroacetic acid were used in all experiments. It was found that the propyl ester caused an increase in the force of individual contractions in the isolated muscle specimens, plus an inability of the muscle to retain tetanus. The substances were determined to have an anticholinesterase effect. The mechanism of cholinesterase inhibition is not yet known. It is probable that the substances acylate the serine hydroxyl of the esterase center of the cholinestersase. 7 references, 1 figure.

  2. Mutagenic activity of phthalate esters in bacterial liquid suspension assays.

    OpenAIRE

    Seed, J L

    1982-01-01

    The mutagenic activities of several phthalate esters have been evaluated in an 8-azaguanine resistance assay in Salmonella typhimurium. Three phthalate esters were found to be mutagenic: dimethyl phthalate, diethyl phthalate and di-n-butyl phthalate. A number of other phthalate esters were not found to be mutagenic, including di(2-ethylhexyl) phthalate, di-n-octyl phthalate, diallyl phthalate, diisobutyl phthalate and diisodecyl phthalate. A metabolite of di(2-ethylhexyl) phthalate, 2-ethylhe...

  3. Effects of protein kinase C activators on phorbol ester-sensitive and -resistant EL4 thymoma cells.

    Science.gov (United States)

    Sansbury, H M; Wisehart-Johnson, A E; Qi, C; Fulwood, S; Meier, K E

    1997-09-01

    Phorbol ester-sensitive EL4 murine thymoma cells respond to phorbol 12-myristate 13-acetate with activation of ERK mitogen-activated protein kinases, synthesis of interleukin-2, and death, whereas phorbol ester-resistant variants of this cell line do not exhibit these responses. Additional aspects of the resistant phenotype were examined, using a newly-established resistant cell line. Phorbol ester induced morphological changes, ERK activation, calcium-dependent activation of the c-Jun N-terminal kinase (JNK), interleukin-2 synthesis, and growth inhibition in sensitive but not resistant cells. A series of protein kinase C activators caused membrane translocation of protein kinase C's (PKCs) alpha, eta, and theta in both cell lines. While PKC eta was expressed at higher levels in sensitive than in resistant cells, overexpression of PKC eta did not restore phorbol ester-induced ERK activation to resistant cells. In sensitive cells, PKC activators had similar effects on cell viability and ERK activation, but differed in their abilities to induce JNK activation and interleukin-2 synthesis. PD 098059, an inhibitor of the mitogen activated protein (MAP)/ERK kinase kinase MEK, partially inhibited ERK activation and completely blocked phorbol ester-induced cell death in sensitive cells. Thus MEK and/or ERK activation, but not JNK activation or interleukin-2 synthesis, appears to be required for phorbol ester-induced toxicity. Alterations in phorbol ester response pathways, rather than altered expression of PKC isoforms, appear to confer phorbol ester resistance to EL4 cells.

  4. Interpenetrating polymer networks based on cyanate ester and fluorinated ethynyl-terminated imide oligomers

    Directory of Open Access Journals (Sweden)

    Y. Wen

    2017-12-01

    Full Text Available Highly soluble fluorinated ethynyl-terminated imide (FETI oligomers were prepared via a conventional one-step method in m-cresol, using 4, 4′-(hexafluoroisopropylidene diphthalic anhydride and 2, 2′-bis(trifluoromethyl benzidine as the monomers, and ethynylphthalic anhydride as the end-capper; then interpenetrating polymer networks (IPN were formulated from FETI oligomers and bisphenol A dicyanate ester (BADCy through a solvent-free procedure, and their thermal, mechanical, and dielectric properties were fully characterized. The curing mechanism was studied by model reactions using nitrogen nuclear magnetic resonance. As evidenced by differential scanning calorimetry analysis and rheological measurements, the FETI/BADCy blends exhibited lower curing temperature and shorter gelation time in comparison with pure BADCy due to the catalytic effects of ethynyl and residue amic acid groups. The properties of IPNs were fully compared with those of polycyanurate, and the results revealed that the incorporation of FETI into cyanate ester resins could significantly improve the toughness, glass transition temperatures, mechanical and dielectric properties of the resultant IPNs.

  5. Effect of alkyl chain length in the terminal ester group on mesomorphic properties of new chiral lactic acid derivatives

    Czech Academy of Sciences Publication Activity Database

    Kohout, M.; Bubnov, Alexej; Šturala, J.; Novotná, Vladimíra; Svoboda, J.

    2016-01-01

    Roč. 43, č. 10 (2016), s. 1472-1485 ISSN 0267-8292 R&D Projects: GA MŠk(CZ) LD14007 Institutional support: RVO:68378271 Keywords : chiral liquid crystal * lactic acid derivative * terminal ester group * mesomorphic properties * dielectric spectroscopy * layer shrinkage Subject RIV: JJ - Other Materials Impact factor: 2.661, year: 2016

  6. Controlled release from aspirin based linear biodegradable poly(anhydride esters) for anti-inflammatory activity.

    Science.gov (United States)

    Dasgupta, Queeny; Movva, Sahitya; Chatterjee, Kaushik; Madras, Giridhar

    2017-08-07

    This work reports the synthesis of a novel, aspirin-loaded, linear poly (anhydride ester) and provides mechanistic insights into the release of aspirin from this polymer for anti-inflammatory activity. As compared to conventional drug delivery systems that rely on diffusion based release, incorporation of bioactives in the polymer backbone is challenging and high loading is difficult to achieve. In the present study, we exploit the pentafunctional sugar alcohol (xylitol) to provide sites for drug (aspirin) attachment at its non-terminal OH groups. The terminal OH groups are polymerized with a diacid anhydride. The hydrolysis of the anhydride and ester bonds under physiological conditions release aspirin from the matrix. The resulting poly(anhydride ester) has high drug loading (53%) and displays controlled release kinetics of aspirin. The polymer releases 8.5 % and 20%, of the loaded drug in one and four weeks, respectively and has a release rate constant of 0.0035h -0.61 . The release rate is suitable for its use as an anti-inflammatory agent without being cytotoxic. The polymer exhibits good cytocompatibility and anti-inflammatory properties and may find applications as injectable or as an implantable bioactive material. The physical insights into the release mechanism can provide development of other drug loaded polymers. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. How anacetrapib inhibits the activity of the cholesteryl ester transfer protein? Perspective through atomistic simulations

    DEFF Research Database (Denmark)

    Aijanen, T.; Koivuniemi, A.; Javanainen, M.

    2014-01-01

    Cholesteryl ester transfer protein (CETP) mediates the reciprocal transfer of neutral lipids (cholesteryl esters, triglycerides) and phospholipids between different lipoprotein fractions in human blood plasma. A novel molecular agent known as anacetrapib has been shown to inhibit CETP activity...... and thereby raise high density lipoprotein (HDL)-cholesterol and decrease low density lipoprotein (LDL)-cholesterol, thus rendering CETP inhibition an attractive target to prevent and treat the development of various cardiovascular diseases. Our objective in this work is to use atomistic molecular dynamics...... simulations to shed light on the inhibitory mechanism of anacetrapib and unlock the interactions between the drug and CETP. The results show an evident affinity of anacetrapib towards the concave surface of CETP, and especially towards the region of the N-terminal tunnel opening. The primary binding site...

  8. Carboxylesterase activities toward pesticide esters in crops and weeds.

    Science.gov (United States)

    Gershater, Markus; Sharples, Kate; Edwards, Robert

    2006-12-01

    Proteins were extracted from maize, rice, sorghum, soybean, flax and lucerne; the weeds Abutilon theophrasti, Echinochloa crus-galli, Phalaris canariensis, Setaria faberii, Setaria viridis, Sorghum halepense and the model plant Arabidopsis thaliana and assayed for carboxylesterase activity toward a range of xenobiotics. These included the pro-herbicidal esters clodinafop-propargyl, fenoxaprop-ethyl, fenthioprop-ethyl, methyl-2,4-dichlorophenoxyacetic acid (2,4-d-methyl), bromoxynil-octanoate, the herbicide-safener cloquintocet-mexyl and the pyrethroid insecticide permethrin. Highest activities were recorded with alpha-naphthyl acetate and methylumbelliferyl acetate. Esters of p-nitrophenol were also readily hydrolysed, with turnover declining as the chain length of the acyl component increased. Activities determined with model substrates were much higher than those observed with pesticide esters and were of limited value in predicting the relative rates of hydrolysis of the crop protection agents. Substrate preferences with the herbicides were typically 2,4-d-methyl>clodinafop-propargyl>fenthioprop-ethyl, fenoxaprop-ethyl and bromoxynil-octanoate. Isoelectric focussing in conjunction with staining for esterase activity using alpha-naphthyl acetate as substrate confirmed the presence of multiple carboxylesterase isoenzymes in each plant, with major qualitative differences observed between species. The presence of serine hydrolases among the resolved isoenzymes was confirmed through their selective inhibition by the organophosphate insecticide paraoxon. Our studies identify potentially exploitable differences between crops and weeds in their ability to bioactivate herbicides by enzymic hydrolysis and also highlight the usefulness of Arabidopsis as a plant model to study xenobiotic biotransformation.

  9. Effects of phorbol ester on mitogen-activated protein kinase kinase activity in wild-type and phorbol ester-resistant EL4 thymoma cells.

    Science.gov (United States)

    Gause, K C; Homma, M K; Licciardi, K A; Seger, R; Ahn, N G; Peterson, M J; Krebs, E G; Meier, K E

    1993-08-05

    Phorbol ester-sensitive and -resistant EL4 thymoma cell lines differ in their ability to activate mitogen-activated protein kinase (MAPK) in response to phorbol ester. Treatment of wild-type EL4 cells with phorbol ester results in the rapid activations of MAPK and pp90rsk kinase, a substrate for MAPK, while neither kinase is activated in response to phorbol ester in variant EL4 cells. This study examines the activation of MAPK kinase (MAPKK), an activator of MAPK, in wild-type and variant EL4 cells. Phosphorylation of a 40-kDa substrate, identified as MAPK, was observed following in vitro phosphorylation reactions using cytosolic extracts or Mono Q column fractions prepared from phorbol ester-treated wild-type EL4 cells. MAPKK activity coeluted with a portion of the inactive MAPK upon Mono Q anion-exchange chromatography, permitting detection of the MAPKK activity in fractions containing both kinases. This MAPKK activity was present in phorbol ester-treated wild-type cells, but not in phorbol ester-treated variant cells or in untreated wild-type or variant cells. The MAPKK from wild-type cells was able to activate MAPK prepared from either wild-type or variant cells. MAPKK activity could be stimulated in both wildtype and variant EL4 cells in response to treatment of cells with okadaic acid. These results indicate that the failure of variant EL4 cells to activate MAP kinase in response to phorbol ester is due to a failure to activate MAPKK. Therefore, the step that confers phorbol ester resistance to variant EL4 cells lies between the activation of protein kinase C and the activation of MAPKK.

  10. Acridinium esters as high-specific-activity labels in immunoassay

    International Nuclear Information System (INIS)

    Weeks, I.; Beheshti, I.; McCapra, F.; Campbell, A.K.; Woodhead, J.S.

    1983-01-01

    A chemiluminescent acridinium ester has been synthesized that reacts spontaneously with proteins to yield stable, immunoreactive derivatives of high specific activity. The compound has been used to prepare chemiluminescent monoclonal antibodies to human alpha 1-fetoprotein having average incorporation ratios as great as 2.8 mol of label per mole of antibody, which corresponds to a detection limit of approximately 8 X 10(-19) mol. These antibodies have been used in the preliminary development of a two-site immunochemiluminometric assay for human alpha 1-fetoprotein, which requires only a 30-min incubation and a quantification time of 5 s per sample

  11. How anacetrapib inhibits the activity of the cholesteryl ester transfer protein? Perspective through atomistic simulations.

    Directory of Open Access Journals (Sweden)

    Tarja Äijänen

    2014-11-01

    Full Text Available Cholesteryl ester transfer protein (CETP mediates the reciprocal transfer of neutral lipids (cholesteryl esters, triglycerides and phospholipids between different lipoprotein fractions in human blood plasma. A novel molecular agent known as anacetrapib has been shown to inhibit CETP activity and thereby raise high density lipoprotein (HDL-cholesterol and decrease low density lipoprotein (LDL-cholesterol, thus rendering CETP inhibition an attractive target to prevent and treat the development of various cardiovascular diseases. Our objective in this work is to use atomistic molecular dynamics simulations to shed light on the inhibitory mechanism of anacetrapib and unlock the interactions between the drug and CETP. The results show an evident affinity of anacetrapib towards the concave surface of CETP, and especially towards the region of the N-terminal tunnel opening. The primary binding site of anacetrapib turns out to reside in the tunnel inside CETP, near the residues surrounding the N-terminal opening. Free energy calculations show that when anacetrapib resides in this area, it hinders the ability of cholesteryl ester to diffuse out from CETP. The simulations further bring out the ability of anacetrapib to regulate the structure-function relationships of phospholipids and helix X, the latter representing the structural region of CETP important to the process of neutral lipid exchange with lipoproteins. Altogether, the simulations propose CETP inhibition to be realized when anacetrapib is transferred into the lipid binding pocket. The novel insight gained in this study has potential use in the development of new molecular agents capable of preventing the progression of cardiovascular diseases.

  12. Repellent activity of monoterpenoid esters with neurotransmitter amino acids against yellow fever mosquito, Aedes aegypti

    Directory of Open Access Journals (Sweden)

    Nesterkina Mariia

    2018-03-01

    Full Text Available Repellent activity of monoterpenoid esters (1-6 with neurotransmitter amino acids (GABA and glycine was investigated against Aedes aegypti by using a “cloth-patch” assay and compared to reference standard N,N-diethyl-3-methylbenzamide (DEET. Monoterpenoid esters showed repellent activity with minimum effective dosages (MED in the range of 0.031-0.469 mg/cm2. The carvacrol ester of GABA (2, MED of 0.031 ± 0.008 mg/cm2 exhibited the highest repellency of six monoterpenoid esters tested in comparison to the standard repellent DEET (MED of 0.009 ± 0.002 mg/cm2; however, the repellent activity of carvacrol-glycine ester (5 decreased 4-fold compared to the carvacrol-GABA derivative (2. The repellent activities of menthol GABA (1, MED= 0.375 ± 0.000 mg/cm2 and glycine ester (4, MED=0.312 ± 0.063 mg/cm2 were similar The guaiacol-glycine ester (6 was 3.75-fold more efficacious than the guaiacol ester of GABA (3. In the present study, we report repellent efficacy of prolonged exposure to GABA and glycine esters of menthol, carvacrol, guaiacol (1-6 as compared to the repellent activities of their monoterpene moieties alone.

  13. Activities of Jatropha curcas phorbol esters in various bioassays.

    Science.gov (United States)

    Devappa, Rakshit K; Rajesh, Sanjay K; Kumar, Vikas; Makkar, Harinder P S; Becker, Klaus

    2012-04-01

    Jatropha curcas seeds contain 30-35% oil, which can be converted to high quality biodiesel. However, Jatropha oil is toxic, ascribed to the presence of phorbol esters (PEs). In this study, isolated phorbol ester rich fraction (PEEF) was used to evaluate the activity of PEs using three aquatic species based bioassays (snail (Physa fontinalis), brine shrimp (Artemeia salina), daphnia (Daphnia magna)) and microorganisms. In all the bioassays tested, increase in concentration of PEs increased mortality with an EC(50) (48 h) of 0.33, 26.48 and 0.95 mg L(-1) PEs for snail, artemia and daphnia, respectively. The sensitivity of various microorganisms for PEs was also tested. Among the bacterial species tested, Streptococcus pyogenes and Proteus mirabilis were highly susceptible with a minimum inhibitory concentration (MIC) of 215 mg L(-1) PEs; and Pseudomonas putida were also sensitive with MIC of 251 mg L(-1) PEs. Similarly, Fusarium species of fungi exhibited EC(50) of 58 mg L(-1) PEs, while Aspergillus niger and Curvularia lunata had EC(50) of 70 mg L(-1). The snail bioassay was most sensitive with 100% snail mortality at 1 μg of PEs mL(-1). In conclusion, snail bioassay could be used to monitor PEs in Jatropha derived products such as oil, biodiesel, fatty acid distillate, kernel meal, cake, glycerol or for contamination in soil or other environmental matrices. In addition, PEs with molluscicidal/antimicrobial activities could be utilized for agricultural and pharmaceutical applications. Copyright © 2011 Elsevier Inc. All rights reserved.

  14. A Two-terminal Active Capacitor

    DEFF Research Database (Denmark)

    Wang, Haoran; Wang, Huai

    2017-01-01

    This letter proposes a concept of two-terminal active capacitor implemented by power semiconductor switches and passive elements. The active capacitor has the same level of convenience as a passive one with two power terminals only. It is application independent and can be specified by rated...... voltage, ripple current, equivalent series resistance, and operational frequency range. The concept, control method, self-power scheme, and impedance characteristics of the active capacitor are presented. A case study of the proposed active capacitor for a capacitive DC-link application is discussed....... The results reveal a significantly lower overall energy storage of passive elements and a reduced cost to fulfill a specific reliability target, compared to a passive capacitor solution. Proof-of-concept experimental results are given to verify the functionality of the proposed capacitor....

  15. Potentiation of insulin release in response to amino acid methyl esters correlates to activation of islet glutamate dehydrogenase activity

    DEFF Research Database (Denmark)

    Kofod, Hans; Lernmark, A; Hedeskov, C J

    1986-01-01

    Column perifusion of mouse pancreatic islets was used to study the ability of amino acids and their methyl esters to influence insulin release and activate islet glutamate dehydrogenase activity. In the absence of L-glutamine, L-serine and the methyl ester of L-phenylalanine, but neither L...... glutamate dehydrogenase activity showed that only the two methyl esters of L-phenylalanine and L-serine activated the enzyme. It is concluded that the mechanism by which methyl esters of amino acids potentiate insulin release is most likely to be mediated by the activation of pancreatic beta-cell glutamate...

  16. Anti-oedematous activities of the main triterpendiol esters of marigold (Calendula officinalis L.).

    Science.gov (United States)

    Zitterl-Eglseer, K; Sosa, S; Jurenitsch, J; Schubert-Zsilavecz, M; Della Loggia, R; Tubaro, A; Bertoldi, M; Franz, C

    1997-07-01

    Separation and isolation of the genuine faradiol esters (1, 2) from flower heads of Marigold (Calendula (officinalis L., Asteraceae) could be achieved by means of repeated column chromatography (CC) and HPLC for the first time. Structure elucidation of faradiol-3-myristic acid ester 1, faradiol-3-palmitic acid ester 2 and psi-taraxasterol 3 has been also performed, without any previous degradation by means of MS, 1H-NMR, 13C-NMR and 2D-NMR experiments. The anti-oedematous activities of these three compounds were tested by means of inhibition of Croton oil-induced oedema of the mouse ear. Both faradiol esters showed nearly the same dose dependent anti-oedematous activity and no significant synergism appeared with their mixture. The free monol, psi-taraxasterol, had a slightly lower effect. Furthermore, faradiol was more active than its esters and than psi-taraxasterol and showed the same effect as an equimolar dose of indomethacin.

  17. A Lactobacillus plantarum Esterase Active on a Broad Range of Phenolic Esters

    Science.gov (United States)

    Esteban-Torres, María; Landete, José María; Reverón, Inés; Santamaría, Laura; de las Rivas, Blanca

    2015-01-01

    Lactobacillus plantarum is the lactic acid bacterial species most frequently found in the fermentation of food products of plant origin on which phenolic compounds are abundant. L. plantarum strains showed great flexibility in their ability to adapt to different environments and growth substrates. Of 28 L. plantarum strains analyzed, only cultures from 7 strains were able to hydrolyze hydroxycinnamic esters, such as methyl ferulate or methyl caffeate. As revealed by PCR, only these seven strains possessed the est_1092 gene. When the est_1092 gene was introduced into L. plantarum WCFS1 or L. lactis MG1363, their cultures acquired the ability to degrade hydroxycinnamic esters. These results support the suggestion that Est_1092 is the enzyme responsible for the degradation of hydroxycinnamic esters on the L. plantarum strains analyzed. The Est_1092 protein was recombinantly produced and biochemically characterized. Surprisingly, Est_1092 was able to hydrolyze not only hydroxycinnamic esters, since all the phenolic esters assayed were hydrolyzed. Quantitative PCR experiments revealed that the expression of est_1092 was induced in the presence of methyl ferulate, an hydroxycinnamic ester, but was inhibited on methyl gallate, an hydroxybenzoic ester. As Est_1092 is an enzyme active on a broad range of phenolic esters, simultaneously possessing feruloyl esterase and tannase activities, its presence on some L. plantarum strains provides them with additional advantages to survive and grow on plant environments. PMID:25746986

  18. A Lactobacillus plantarum esterase active on a broad range of phenolic esters.

    Science.gov (United States)

    Esteban-Torres, María; Landete, José María; Reverón, Inés; Santamaría, Laura; de las Rivas, Blanca; Muñoz, Rosario

    2015-05-01

    Lactobacillus plantarum is the lactic acid bacterial species most frequently found in the fermentation of food products of plant origin on which phenolic compounds are abundant. L. plantarum strains showed great flexibility in their ability to adapt to different environments and growth substrates. Of 28 L. plantarum strains analyzed, only cultures from 7 strains were able to hydrolyze hydroxycinnamic esters, such as methyl ferulate or methyl caffeate. As revealed by PCR, only these seven strains possessed the est_1092 gene. When the est_1092 gene was introduced into L. plantarum WCFS1 or L. lactis MG1363, their cultures acquired the ability to degrade hydroxycinnamic esters. These results support the suggestion that Est_1092 is the enzyme responsible for the degradation of hydroxycinnamic esters on the L. plantarum strains analyzed. The Est_1092 protein was recombinantly produced and biochemically characterized. Surprisingly, Est_1092 was able to hydrolyze not only hydroxycinnamic esters, since all the phenolic esters assayed were hydrolyzed. Quantitative PCR experiments revealed that the expression of est_1092 was induced in the presence of methyl ferulate, an hydroxycinnamic ester, but was inhibited on methyl gallate, an hydroxybenzoic ester. As Est_1092 is an enzyme active on a broad range of phenolic esters, simultaneously possessing feruloyl esterase and tannase activities, its presence on some L. plantarum strains provides them with additional advantages to survive and grow on plant environments. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  19. Induction of transcription from the long terminal repeat of Moloney murine sarcoma provirus by UV-irradiation, x-irradiation, and phorbol ester

    International Nuclear Information System (INIS)

    Lin, C.S.; Goldthwait, D.A.; Samols, D.

    1990-01-01

    The long terminal repeat (LTR) of Moloney murine sarcoma virus (Mo-MuSV) was used as a model system to study the stress response of mammalian cells to physical carcinogens. The chloramphenicol acetyltransferase (CAT) gene was inserted between two Mo-MuSV LTRs, and the LTR-CAT-LTR construct was used for virus production and was integrated into the genome of NIH 3T3 cells in the proviral form. This construct was used to assure that the integrated CAT gene was driven by the promoter of the LTR. Expression of the CAT gene was stimulated 4-fold by UV irradiation, and the peak of activity was observed at 18 hr. In contrast, stimulation of the CAT expression after x-irradiation was 2-fold and occurred at 6 hr. Phorbol myristate acetate also stimulated CAT activity 4-fold with a peak at 6 hr. Down-regulation of protein kinase C blocked totally the response to x-irradiation but only partially the response to UV. The protein kinase inhibitor H7 blocked the response to treatment by UV, x-ray, and phorbol ester

  20. Integrated modulation of phorbol ester-induced Raf activation in EL4 lymphoma cells.

    Science.gov (United States)

    Han, Shujie; Meier, Kathryn E

    2009-05-01

    The EL4 murine lymphoma cell line exists in variant phenotypes that differ with respect to responses to the tumor promoter phorbol 12-myristate 13-acetate (PMA1). Previous work showed that "PMA-sensitive" cells, characterized by a high magnitude of PMA-induced Erk activation, express RasGRP, a phorbol ester receptor that directly activates Ras. In "PMA-resistant" and "intermediate" EL4 cell lines, PMA induces Erk activation to lesser extents, but with a greater response in intermediate cells. In the current study, these cell lines were used to examine mechanisms of Raf-1 modulation. Phospho-specific antibodies were utilized to define patterns and kinetics of Raf-1 phosphorylation on several sites. Further studies showed that Akt is constitutively activated to a greater extent in PMA-resistant than in PMA-sensitive cells, and also to a greater extent in resistant than intermediate cells. Akt negatively regulates Raf-1 activation (Ser259), partially explaining the difference between resistant and intermediate cells. Erk activation exerts negative feedback on Raf-1 (Ser289/296/301), thus resulting in earlier termination of the signal in cells with a higher level of Erk activation. RKIP, a Raf inhibitory protein, is expressed at higher levels in resistant cells than in sensitive or intermediate cells. Knockdown of RKIP increases Erk activation and also negative feedback. In conclusion, this study delineates Raf-1 phosphorylation events occurring in response to PMA in cell lines with different extents of Erk activation. Variations in the levels of expression and activation of multiple signaling proteins work in an integrated fashion to modulate the extent and duration of Erk activation.

  1. Palladium-Catalyzed ortho-Olefination of Phenyl Acetic and Phenyl Propylacetic Esters via C-H Bond Activation.

    Science.gov (United States)

    Hu, Jundie; Guan, Mingyu; Han, Jian; Huang, Zhi-Bin; Shi, Da-Qing; Zhao, Yingsheng

    2015-08-21

    A highly regioselective palladium-catalyzed ester-directed ortho-olefination of phenyl acetic and propionic esters with olefins via C-H bond activation has been developed. A wide variety of phenyl acetic and propionic esters were tolerated in this transformation, affording the corresponding olefinated aromatic compounds. The ortho-olefination of heterocyclic acetic and propionic esters also took place smoothly giving the products in good yields, thus proving the potential utility of this protocol in synthetic chemistry.

  2. Substrate-Competitive Activity-Based Profiling of Ester Prodrug Activating Enzymes.

    Science.gov (United States)

    Xu, Hao; Majmudar, Jaimeen D; Davda, Dahvid; Ghanakota, Phani; Kim, Ki H; Carlson, Heather A; Showalter, Hollis D; Martin, Brent R; Amidon, Gordon L

    2015-09-08

    Understanding the mechanistic basis of prodrug delivery and activation is critical for establishing species-specific prodrug sensitivities necessary for evaluating preclinical animal models and potential drug-drug interactions. Despite significant adoption of prodrug methodologies for enhanced pharmacokinetics, functional annotation of prodrug activating enzymes is laborious and often unaddressed. Activity-based protein profiling (ABPP) describes an emerging chemoproteomic approach to assay active site occupancy within a mechanistically similar enzyme class in native proteomes. The serine hydrolase enzyme family is broadly reactive with reporter-linked fluorophosphonates, which have shown to provide a mechanism-based covalent labeling strategy to assay the activation state and active site occupancy of cellular serine amidases, esterases, and thioesterases. Here we describe a modified ABPP approach using direct substrate competition to identify activating enzymes for an ethyl ester prodrug, the influenza neuraminidase inhibitor oseltamivir. Substrate-competitive ABPP analysis identified carboxylesterase 1 (CES1) as an oseltamivir-activating enzyme in intestinal cell homogenates. Saturating concentrations of oseltamivir lead to a four-fold reduction in the observed rate constant for CES1 inactivation by fluorophosphonates. WWL50, a reported carbamate inhibitor of mouse CES1, blocked oseltamivir hydrolysis activity in human cell homogenates, confirming CES1 is the primary prodrug activating enzyme for oseltamivir in human liver and intestinal cell lines. The related carbamate inhibitor WWL79 inhibited mouse but not human CES1, providing a series of probes for analyzing prodrug activation mechanisms in different preclinical models. Overall, we present a substrate-competitive activity-based profiling approach for broadly surveying candidate prodrug hydrolyzing enzymes and outline the kinetic parameters for activating enzyme discovery, ester prodrug design, and

  3. An Update on Oligosaccharides and Their Esters from Traditional Chinese Medicines: Chemical Structures and Biological Activities

    OpenAIRE

    Chen, Xiang-Yang; Wang, Ru-Feng; Liu, Bin

    2015-01-01

    A great number of naturally occurring oligosaccharides and oligosaccharide esters have been isolated from traditional Chinese medicinal plants, which are used widely in Asia and show prominent curative effects in the prevention and treatment of kinds of diseases. Numerous in vitro and in vivo experiments have revealed that oligosaccharides and their esters exhibited various activities, including antioxidant, antidepressant, cytotoxic, antineoplastic, anti-inflammatory, neuroprotective, cerebr...

  4. Synthesis and biological evaluation of arctigenin ester and ether derivatives as activators of AMPK.

    Science.gov (United States)

    Shen, Sida; Zhuang, Jingjing; Chen, Yijia; Lei, Min; Chen, Jing; Shen, Xu; Hu, Lihong

    2013-07-01

    A series of new arctigenin and 9-deoxy-arctigenin derivatives bearing different ester and ether side chains at the phenolic hydroxyl positions are designed, synthesized, and evaluated for activating AMPK potency in L6 myoblasts. Initial biological evaluation indicates that some alkyl ester and phenethyl ether arctigenin derivatives display potential activities in AMPK phosphorylation improvement. Further structure-activity relationship analysis shows that arctigenin ester derivatives 3a, 3h and 9-deoxy-arctigenin phenethyl ether derivatives 6a, 6c, 6d activate AMPK more potently than arctigenin. Moreover, the 2-(3,4-dimethoxyphenyl)ethyl ether moiety of 6c has been demonstrated as a potential functional group to improve the effect of AMPK phosphorylation. The structural optimization of arctigenin leads to the identification of 6c as a promising lead compound that exhibits excellent activity in AMPK activation. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

  5. Microalgal fatty acid methyl ester a new source of bioactive compounds with antimicrobial activity

    Directory of Open Access Journals (Sweden)

    Arumugham Suresh

    2014-09-01

    Full Text Available Objective: To evaluate fatty acid composition and the antimicrobial activity of the major fraction of fatty acid methyl ester (FAME extracts from three microalgae collected from freshwater lakes in Theni District, Tamil Nadu, India. Methods: Antimicrobial study was carried out by well diffusion method against bacterial as well as fungal pathogens such as Escherichia coli, Staphylococcus aureus, Enterobacter sp., Klebsiella sp., Salmonella typhi, Fusarium sp., Cryptococcus sp., Candida sp., and Aspergillus niger and Aspergillus flavus. The FAME profiles were determined through gas chromatography with a flame ionization detector. Results: The FAME was found to be radial effective in inhibiting the radial growth of both bacterial and fungal pathogens. The FAME extracts exhibited the antibacterial activity against three clinical pathogens, namely, Escherichia coli, Salmonella typhi and Enterobacter sp. with the maximum zone of inhibition of 12.0 mm, 12.0 mm and 11.0 mm, respectively. The FAME showed moderate antifungal activity against Cryptococcus sp. (11.8 mm, Aspergillus niger (10.5 mm, Candida sp. (11.8 mm and Fusarium sp. (10.4 mm. Gas chromatography-flame ionization detector analysis revealed about 30 different FAMEs. Conclusions: We assume that the observed antimicrobial potency may be due to the abundance of erucic acid methyl ester (C22:0, arachidic acid methyl ester (C20:0, palmitic acid methyl ester (C16:0, cis-11-eicosenoicmethyl ester (C20:1, cis-11, 14-eicosadienoic acid methyl ester (C20:2 and linolenic acid methyl ester (C18:3 in FAMEs which appears to be promising to treat microbial diseases.

  6. Quorum Sensing Inhibition and Structure–Activity Relationships of β-Keto Esters

    Directory of Open Access Journals (Sweden)

    Stephanie Forschner-Dancause

    2016-07-01

    Full Text Available Traditional therapeutics to treat bacterial infections have given rise to multi-drug resistant pathogens, which pose a major threat to human and animal health. In several pathogens, quorum sensing (QS—a cell-cell communication system in bacteria—controls the expression of genes responsible for pathogenesis, thus representing a novel target in the fight against bacterial infections. Based on the structure of the autoinducers responsible for QS activity and other QS inhibitors, we hypothesize that β-keto esters with aryl functionality could possess anti-QS activity. A panel of nineteen β-keto ester analogs was tested for the inhibition of bioluminescence (a QS-controlled phenotype in the marine pathogen Vibrio harveyi. Initial screening demonstrated the need of a phenyl ring at the C-3 position for antagonistic activity. Further additions to the phenyl ring with 4-substituted halo groups or a 3- or 4-substituted methoxy group resulted in the most active compounds with IC50 values ranging from 23 µM to 53 µM. The compounds additionally inhibit green fluorescent protein production by E. coli JB525. Evidence is presented that aryl β-keto esters may act as antagonists of bacterial quorum sensing by competing with N-acyl homoserine lactones for receptor binding. Expansion of the β-keto ester panel will enable us to obtain more insight into the structure–activity relationships needed to allow for the development of novel anti-virulence agents.

  7. Molecular Basis of Prodrug Activation by Human Valacyclovirase, an [alpha]-Amino Acid Ester Hydrolase

    Energy Technology Data Exchange (ETDEWEB)

    Lai, Longsheng; Xu, Zhaohui; Zhou, Jiahai; Lee, Kyung-Dall; Amidon, Gordon L. (Michigan)

    2008-07-08

    Chemical modification to improve biopharmaceutical properties, especially oral absorption and bioavailability, is a common strategy employed by pharmaceutical chemists. The approach often employs a simple structural modification and utilizes ubiquitous endogenous esterases as activation enzymes, although such enzymes are often unidentified. This report describes the crystal structure and specificity of a novel activating enzyme for valacyclovir and valganciclovir. Our structural insights show that human valacyclovirase has a unique binding mode and specificity for amino acid esters. Biochemical data demonstrate that the enzyme hydrolyzes esters of {alpha}-amino acids exclusively and displays a broad specificity spectrum for the aminoacyl moiety similar to tricorn-interacting aminopeptidase F1. Crystal structures of the enzyme, two mechanistic mutants, and a complex with a product analogue, when combined with biochemical analysis, reveal the key determinants for substrate recognition; that is, a flexible and mostly hydrophobic acyl pocket, a localized negative electrostatic potential, a large open leaving group-accommodating groove, and a pivotal acidic residue, Asp-123, after the nucleophile Ser-122. This is the first time that a residue immediately after the nucleophile has been found to have its side chain directed into the substrate binding pocket and play an essential role in substrate discrimination in serine hydrolases. These results as well as a phylogenetic analysis establish that the enzyme functions as a specific {alpha}-amino acid ester hydrolase. Valacyclovirase is a valuable target for amino acid ester prodrug-based oral drug delivery enhancement strategies.

  8. Base free aryl coupling of diazonium compounds and boronic esters: self-activation allowing an overall highly practical process.

    Science.gov (United States)

    Bonin, Hélène; Delbrayelle, Dominique; Demonchaux, Patrice; Gras, Emmanuel

    2010-04-21

    Boronic esters have long been considered as poor partners in cross-coupling reactions with arene diazoniums. Here is reported an unprecedented application of self-activated boronic esters in a base-free cross-coupling reaction with diazonium salts under mild and user friendly conditions.

  9. Plasma cholesteryl ester transfer protein mass and phospholipid transfer protein activity are associated with leptin in type 2 diabetes mellitus

    NARCIS (Netherlands)

    Dullaart, R. P. F.; de Vries, R.; Dallinga-Thie, G. M.; van Tol, A.; Sluiter, W. J.

    Adipose tissue contributes to plasma levels of lipid transfer proteins and is also the major source of plasma adipokines. We hypothesized that plasma cholesteryl ester transfer protein (CETP) mass, phospholipid transfer protein (PLTP) activity and cholesteryl ester transfer (CET, a measure of CETP

  10. Benzofuranyl Esters: Synthesis, Crystal Structure Determination, Antimicrobial and Antioxidant Activities

    Directory of Open Access Journals (Sweden)

    C. S. Chidan Kumar

    2015-09-01

    Full Text Available A series of five new 2‐(1‐benzofuran‐2‐yl‐2‐oxoethyl 4-(un/substitutedbenzoates 4(a–e, with the general formula of C8H5O(C=OCH2O(C=OC6H4X, X = H, Cl, CH3, OCH3 or NO2, was synthesized in high purity and good yield under mild conditions. The synthesized products 4(a–e were characterized by FTIR, 1H-, 13C- and 1H-13C HMQC NMR spectroscopic analysis and their 3D structures were confirmed by single-crystal X-ray diffraction studies. These compounds were screened for their antimicrobial and antioxidant activities. The tested compounds showed antimicrobial ability in the order of 4b < 4a < 4c < 4d < 4e and the highest potency with minimum inhibition concentration (MIC value of 125 µg/mL was observed for 4e. The results of antioxidant activities revealed the highest activity for compound 4e (32.62% ± 1.34% in diphenyl-2-picrylhydrazyl (DPPH radical scavenging, 4d (31.01% ± 4.35% in ferric reducing antioxidant power (FRAP assay and 4a (27.11% ± 1.06% in metal chelating (MC activity.

  11. Microalgal fatty acid methyl ester a new source of bioactive compounds with antimicrobial activity

    OpenAIRE

    Arumugham Suresh; Ramasamy Praveenkumar; Ramasamy Thangaraj; Felix Lewis Oscar; Edachery Baldev; Dharumadurai Dhanasekaran; Nooruddin Thajuddin

    2014-01-01

    Objective: To evaluate fatty acid composition and the antimicrobial activity of the major fraction of fatty acid methyl ester (FAME) extracts from three microalgae collected from freshwater lakes in Theni District, Tamil Nadu, India. Methods: Antimicrobial study was carried out by well diffusion method against bacterial as well as fungal pathogens such as Escherichia coli, Staphylococcus aureus, Enterobacter sp., Klebsiella sp., Salmonella typhi, Fusarium sp., Cryptococcus sp.,...

  12. Degradation of Jatropha curcas phorbol esters derived from Jatropha oil cake and their tumor-promoting activity.

    Science.gov (United States)

    Nakao, Motoyuki; Hasegawa, Go; Yasuhara, Tadashi; Ishihara, Yoko

    2015-04-01

    Large amount of oil cake is generated during biodiesel production from Jatropha seeds. Although Jatropha oil cake is rich in plant nutrients, presence of toxic phorbol esters restricts the usage of oil cake as a fertilizer. The objective of this study is to evaluate the components and tumor promoting activity of phorbol esters in Jatropha oil cake-supplemented soil and plants grown in the treated soil. Contents and their biological activity of Jatropha phorbol esters in soil and plants were sequentially analyzed by high-performance liquid chromatography (HPLC) and in vitro cell transformation assay, respectively. Disappearance of Jatropha phorbol-ester-specific peaks were followed with HPLC during incubation of Jatropha oil cake with soil for five weeks. Along with the degradation of Jatropha phorbol ester in soil, tumor-promoting activity in the sample was also attenuated and ultimately disappeared. Jatropha phorbol esters and tumor promoting activity were not detected from mustard spinach grown in the Jatropha oil cake-supplemented soil. In addition, the esterase KM109 degrades DHPB (see definition below; Jatropha phorbol ester) and reduced its tumor-promoting activity. From these data, we conclude: (1) components and tumor promoting activity of Jatropha phorbol esters in the oil cake disappeared completely by incubation with soil for five-week, (2) Jatropha phorbol esters did not transfer into plants grown in the Jatropha oil cake-supplemented soil, and (3) DHPB can be degraded by esterase from soil bacterium. These observations are useful for utilization of Jatropha oil cake as a fertilizer. Copyright © 2014 Elsevier Inc. All rights reserved.

  13. Synthesis, Crystal Structure and Biological Activities of Novel Anthranilic(Isophthalic) Acid Esters

    Institute of Scientific and Technical Information of China (English)

    YAN Tao; YU Guan-ping; LIU Peng-fei; XIONG Li-xia; YU Shu-jing; LI Zheng-ming

    2012-01-01

    In search of environmentally benign insecticides with high activity,low toxicity and low resistance,a series of novel anthranilic(isophthalic) acid esters was designed and synthesized based on the structure of ryanodine modulating agent.All the compounds were characterized by 1H NMR spectra,elemental analysis or high resolution mass spectrometry(HRMS).The preliminary results of biological activity assessment indicate that some of the title compounds exhibit certain but unremarkable insecticidal activity against Mythimna separata Walker at 200 mg/L and fungicidal activities against five funguses at 50 mg/L.

  14. Anti-Mycobacterium tuberculosis Activity of Esters of Quinoxaline 1,4-Di-N-Oxide

    Directory of Open Access Journals (Sweden)

    Isidro Palos

    2018-06-01

    Full Text Available Tuberculosis continues to be a public health problem in the world, and drug resistance has been a major obstacle in its treatment. Quinoxaline 1,4-di-N-oxide has been proposed as a scaffold to design new drugs to combat this disease. To examine the efficacy of this compound, this study evaluates methyl, ethyl, isopropyl, and n-propyl esters of quinoxaline 1,4-di-N-oxide derivatives in vitro against Mycobacterium tuberculosis (pansusceptible and monoresistant strains. Additionally, the inhibitory effect of esters of quinoxaline 1,4-di-N-oxide on M. tuberculosis gyrase supercoiling was examined, and a stability analysis by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS was also carried out. Results showed that eight compounds (T-007, T-018, T-011, T-069, T-070, T-072, T-085 and T-088 had an activity similar to that of the reference drug isoniazid (minimum inhibitory concentration (MIC = 0.12 µg/mL with an effect on nonreplicative cells and drug monoresistant strains. Structural activity relationship analysis showed that the steric effect of an ester group at 7-position is key to enhancing its biological effects. Additionally, T-069 showed a high stability after 24 h in human plasma at 37 °C.

  15. Sucrose esters from Physalis peruviana calyces with anti-inflammatory activity.

    Science.gov (United States)

    Franco, Luis A; Ocampo, Yanet C; Gómez, Harold A; De la Puerta, Rocío; Espartero, José L; Ospina, Luis F

    2014-11-01

    Physalis peruviana is a native plant from the South American Andes and is widely used in traditional Colombian medicine of as an anti-inflammatory medicinal plant, specifically the leaves, calyces, and small stems in poultice form. Previous studies performed by our group on P. peruviana calyces showed potent anti-inflammatory activity in an enriched fraction obtained from an ether total extract. The objective of the present study was to obtain and elucidate the active compounds from this fraction and evaluate their anti-inflammatory activity in vivo and in vitro. The enriched fraction of P. peruviana was purified by several chromatographic methods to obtain an inseparable mixture of two new sucrose esters named peruviose A (1) and peruviose B (2). Structures of the new compounds were elucidated using spectroscopic methods and chemical transformations. The anti-inflammatory activity of the peruvioses mixture was evaluated using λ-carrageenan-induced paw edema in rats and lipopolysaccharide-activated peritoneal macrophages. Results showed that the peruvioses did not produce side effects on the liver and kidneys and significantly attenuated the inflammation induced by λ-carrageenan in a dosage-dependent manner, probably due to an inhibition of nitric oxide and prostaglandin E2, which was demonstrated in vitro. To our knowledge, this is the first report of the presence of sucrose esters in P. peruviana that showed a potent anti-inflammatory effect. These results suggest the potential of sucrose esters from the Physalis genus as a novel natural alternative to treat inflammatory diseases. Georg Thieme Verlag KG Stuttgart · New York.

  16. Synthesis and Insecticidal Activities of New Ester-Derivatives of Celangulin-V

    Directory of Open Access Journals (Sweden)

    Wenjun Wu

    2011-12-01

    Full Text Available In order to develop new biorational pesticides, ten new 6-substituted ester derivatives of Celangulin-V were designed and synthesized. The structures of the new derivatives were confirmed by IR, 1H-NMR, 13C-NMR and ESI-MS spectral analysis. Insecticidal activities of these compounds were tested against the third-instar larvae of Mythimna separata. Two derivatives (1.1, 1.2 showed higher insecticidal activities than Celangulin-V, with mortality of 75.0% and 83.3%, respectively. While four compounds (1.3, 1.4, 1.7, 1.8 denoted lower insecticidal activities, the others (1.5, 1.6, 1.9, 1.10 revealed no activities at a concentration of 10 mg.mL−1. The results suggest that C-6 substitutions of Celangulin-V are very important in determining the insecticidal activities of its ester-derivatives. That the acetyl (1.1 and propionyl (1.2 derivatives possessed much higher insecticidal activities than Celangulin-V itself supported the view that Celangulin-V has the potential to be a lead structure of semi-synthetic green insecticides.

  17. Facilitation of neocortical presynaptic terminal development by NMDA receptor activation

    Directory of Open Access Journals (Sweden)

    Sceniak Michael P

    2012-02-01

    Full Text Available Abstract Background Neocortical circuits are established through the formation of synapses between cortical neurons, but the molecular mechanisms of synapse formation are only beginning to be understood. The mechanisms that control synaptic vesicle (SV and active zone (AZ protein assembly at developing presynaptic terminals have not yet been defined. Similarly, the role of glutamate receptor activation in control of presynaptic development remains unclear. Results Here, we use confocal imaging to demonstrate that NMDA receptor (NMDAR activation regulates accumulation of multiple SV and AZ proteins at nascent presynaptic terminals of visual cortical neurons. NMDAR-dependent regulation of presynaptic assembly occurs even at synapses that lack postsynaptic NMDARs. We also provide evidence that this control of presynaptic terminal development is independent of glia. Conclusions Based on these data, we propose a novel NMDAR-dependent mechanism for control of presynaptic terminal development in excitatory neocortical neurons. Control of presynaptic development by NMDARs could ultimately contribute to activity-dependent development of cortical receptive fields.

  18. Synthesis and Antiradical Activity of Isoquercitrin Esters with Aromatic Acids and Their Homologues

    Directory of Open Access Journals (Sweden)

    Eva Heřmánková-Vavříková

    2017-05-01

    Full Text Available Isoquercitrin, (IQ, quercetin-3-O-β-d-glucopyranoside is known for strong chemoprotectant activities. Acylation of flavonoid glucosides with carboxylic acids containing an aromatic ring brings entirely new properties to these compounds. Here, we describe the chemical and enzymatic synthesis of a series of IQ derivatives at the C-6″. IQ benzoate, phenylacetate, phenylpropanoate and cinnamate were prepared from respective vinyl esters using Novozym 435 (Lipase B from Candida antarctica immobilized on acrylic resin. The enzymatic procedure gave no products with “hydroxyaromatic” acids, their vinyl esters nor with their benzyl-protected forms. A chemical protection/deprotection method using Steglich reaction yielded IQ 4-hydroxybenzoate, vanillate and gallate. In case of p-coumaric, caffeic, and ferulic acid, the deprotection lead to the saturation of the double bonds at the phenylpropanoic moiety and yielded 4-hydroxy-, 3,4-dihydroxy- and 3-methoxy-4-hydroxy-phenylpropanoates. Reducing capacity of the cinnamate, gallate and 4-hydroxyphenylpropanoate towards Folin-Ciocalteau reagent was significantly lower than that of IQ, while other derivatives displayed slightly better or comparable capacity. Compared to isoquercitrin, most derivatives were less active in 1,1-diphenyl-2-picrylhydrazyl (DPPH radical scavenging, but they showed significantly better 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid, ABTS scavenging activity and were substantially more active in the inhibition of tert-butylhydroperoxide induced lipid peroxidation of rat liver microsomes. The most active compounds were the hydroxyphenylpropanoates.

  19. Active Ester Containing Surfmer for One-Stage Polymer Nanoparticle Surface Functionalization in Mini-Emulsion Polymerization

    Directory of Open Access Journals (Sweden)

    Vanessa L. Albernaz

    2018-04-01

    Full Text Available Functional surface active monomers (surfmers are molecules that combine the functionalities of surface activity, polymerizability, and reactive groups. This study presents an improved pathway for the synthesis of the active ester containing surfmer p-(11-acrylamidoundecanoyloxyphenyl dimethylsulfonium methyl sulfate (AUPDS. Further, the preparation of poly(methyl methacrylate and polystyrene nanoparticles (NPs by mini-emulsion polymerization using AUPDS is investigated, leading to NPs with active ester groups on their surface. By systematically varying reaction parameters and reagent concentrations, it was found that AUPDS feed concentrations between 2–4 mol% yielded narrowly distributed and stable spherical particles with average sizes between 83 and 134 nm for non-cross-linked NPs, and up to 163 nm for cross-linked NPs. By basic hydrolysis of the active ester groups in aqueous dispersion, the positive ζ-potential (ZP was converted into a negative ZP and charge quantities determined by polyelectrolyte titrations before and after hydrolysis were in the same range, indicating that the active ester groups were indeed accessible in aqueous suspension. Increasing cross-linker amounts over 10 mol% also led to a decrease of ZP of NPs, probably due to internalization of the AUPDS during polymerization. In conclusion, by using optimized reaction conditions, it is possible to prepare active ester functionalized NPs in one stage using AUPDS as a surfmer in mini-emulsion polymerization.

  20. Epimerization-free C-terminal peptide activation, elongation and cyclization

    NARCIS (Netherlands)

    Popović, S.

    2015-01-01

    C-terminal peptide activation and cyclization reactions are generally accompanied with epimerization (partial loss of C‐terminal stereointegrity). Therefore, the focus of this thesis was to develop epimerization-free methods for C-terminal peptide activation to enable C-terminal peptide elongation

  1. Synthesis and Antifungal Activity of Novel 3-Caren-5-One Oxime Esters

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    Min Huang

    2017-09-01

    Full Text Available A series of novel 3-caren-5-one oxime esters were designed and synthesized by multi-step reactions in an attempt to develop potent antifungal agents. Two E-Z stereoisomers of the intermediate 3-caren-5-one oxime were separated by column chromatography for the first time. The structures of all the intermediates and target compounds were confirmed by UV-Vis, FTIR, NMR, ESI-MS, and elemental analysis. The antifungal activity of the target compounds was preliminarily evaluated by the in vitro method against Fusarium oxysporum f. sp. cucumerinum, Physalospora piricola, Alternaria solani, Cercospora arachidicola, Gibberella zeae, Rhizoeotnia solani, Bipolaris maydis, and Colleterichum orbicalare at 50 µg/mL. The target compounds exhibited best antifungal activity against P. piricola, in which compounds (Z-4r (R = β-pyridyl, (Z-4q (R = α-thienyl, (E-4f′ (R = p-F Ph, (Z-4i (R = m-Me Ph, (Z-4j (R = p-Me Ph, and (Z-4p (R = α-furyl had inhibition rates of 97.1%, 87.4%, 87.4%, 85.0%, 81.9%, and 77.7%, respectively, showing better antifungal activity than that of the commercial fungicide chlorothanil. Also, compound (Z-4r (R = β-pyridyl displayed remarkable antifungal activity against all the tested fungi, with inhibition rates of 76.7%, 82.7%, 97.1%, 66.3%, 74.7%, 93.9%, 76.7% and 93.3%, respectively, showing better or comparable antifungal activity than that of the commercial fungicide chlorothanil. Besides, the E-Z isomers of the target oxime esters were found to show obvious differences in antifungal activity. These results provide an encouraging framework that could lead to the development of potent novel antifungal agents.

  2. Synthesis and Antifungal Activity of Novel 3-Caren-5-One Oxime Esters.

    Science.gov (United States)

    Huang, Min; Duan, Wen-Gui; Lin, Gui-Shan; Li, Kun; Hu, Qiong

    2017-09-12

    A series of novel 3-caren-5-one oxime esters were designed and synthesized by multi-step reactions in an attempt to develop potent antifungal agents. Two E - Z stereoisomers of the intermediate 3-caren-5-one oxime were separated by column chromatography for the first time. The structures of all the intermediates and target compounds were confirmed by UV-Vis, FTIR, NMR, ESI-MS, and elemental analysis. The antifungal activity of the target compounds was preliminarily evaluated by the in vitro method against Fusarium oxysporum f. sp. cucumerinum , Physalospora piricola , Alternaria solani , Cercospora arachidicola , Gibberella zeae, Rhizoeotnia solani , Bipolaris maydis , and Colleterichum orbicalare at 50 µg/mL. The target compounds exhibited best antifungal activity against P. piricola , in which compounds ( Z )- 4r (R = β -pyridyl), ( Z )- 4q (R = α -thienyl), ( E )- 4f' (R = p -F Ph), ( Z )- 4i (R = m -Me Ph), ( Z )- 4j (R = p -Me Ph), and ( Z )- 4p (R = α -furyl) had inhibition rates of 97.1%, 87.4%, 87.4%, 85.0%, 81.9%, and 77.7%, respectively, showing better antifungal activity than that of the commercial fungicide chlorothanil. Also, compound ( Z )- 4r (R = β -pyridyl) displayed remarkable antifungal activity against all the tested fungi, with inhibition rates of 76.7%, 82.7%, 97.1%, 66.3%, 74.7%, 93.9%, 76.7% and 93.3%, respectively, showing better or comparable antifungal activity than that of the commercial fungicide chlorothanil. Besides, the E-Z isomers of the target oxime esters were found to show obvious differences in antifungal activity. These results provide an encouraging framework that could lead to the development of potent novel antifungal agents.

  3. Termination of past nuclear activities at the nuclear research institute

    International Nuclear Information System (INIS)

    Janzekovic, H.; Krizman, M.

    2006-01-01

    Many countries, particularly in Europe, started with nuclear programs in the fifties of the last century. As a consequence nuclear research institutes were established, among them also the Institute Jozef Stefan (IJS) in Slovenia. The nuclear activities at the IJS were related to the development of uranium ore processing technology and technologies comprising uranium oxide and hexafluoride. After very intensive period of nuclear activities the decline began step by step due to different reasons. Various approaches of the termination and decommissioning of facilities were used. The inspectors of the Slovenian Nuclear Safety Administration (SNSA), the responsible authority, started intensive activities at the IJS at the end of 2004. All together 22 research laboratories or research units were included in the inspection program and around 50 researchers of the IJS were involved into the inspection procedures. The inspection was very intensive in the laboratories and storages where past nuclear activities took place and were later on abandoned. As a result several contaminated equipments and sites in addition to around 200 unregistered sources were found. The majority of these sources is related to past nuclear activities. The inspection program related to the terminated research activities is still in progress. The IJS immediately started with the remediation activities including the development of methodology related to decontamination of radioactive liquids. The decontamination of two nuclear laboratories and three different storages of radioactive waste at its sites is in progress. Sixty of the above mentioned sources have been already stored in the Central Interim Storage for Radioactive Waste. (author)

  4. Timeless links replication termination to mitotic kinase activation.

    Directory of Open Access Journals (Sweden)

    Jayaraju Dheekollu

    2011-05-01

    Full Text Available The mechanisms that coordinate the termination of DNA replication with progression through mitosis are not completely understood. The human Timeless protein (Tim associates with S phase replication checkpoint proteins Claspin and Tipin, and plays an important role in maintaining replication fork stability at physical barriers, like centromeres, telomeres and ribosomal DNA repeats, as well as at termination sites. We show here that human Tim can be isolated in a complex with mitotic entry kinases CDK1, Auroras A and B, and Polo-like kinase (Plk1. Plk1 bound Tim directly and colocalized with Tim at a subset of mitotic structures in M phase. Tim depletion caused multiple mitotic defects, including the loss of sister-chromatid cohesion, loss of mitotic spindle architecture, and a failure to exit mitosis. Tim depletion caused a delay in mitotic kinase activity in vivo and in vitro, as well as a reduction in global histone H3 S10 phosphorylation during G2/M phase. Tim was also required for the recruitment of Plk1 to centromeric DNA and formation of catenated DNA structures at human centromere alpha satellite repeats. Taken together, these findings suggest that Tim coordinates mitotic kinase activation with termination of DNA replication.

  5. Immobilization of Yarrowia lipolytica lipase Ylip2 for the biocatalytic synthesis of phytosterol ester in a water activity controlled reactor.

    Science.gov (United States)

    Cui, Caixia; Guan, Nan; Xing, Chen; Chen, Biqiang; Tan, Tianwei

    2016-10-01

    In this work, phytosterol ester was synthesized using Yarrowia lipolytica lipase Ylip2 that had been immobilized on inorganic support in a solvent-free system and reacted in a computer-aided water activity controlled bioreactor. The immobilization of Ylip2 on celite led to a remarkable increase in the phytosterol conversion compared to that of free lipase. An investigation of the reaction conditions were oleic acid as the fatty acid variety, 10,000U/g substrate, and a temperature of 50°C for phytosterol ester synthesis. Controlling of the water activity at a set point was accomplished by the introduction of dry air through the reaction medium at a digital feedback controlled flow rate. For the esterification of phytosterol ester, a low (15%) water activity resulted in a considerable improvement in phytosterol conversion (91.1%) as well as a decreased reaction time (78h). Furthermore, Ylip2 lipase immobilized on celite retained 90% esterification activity for the synthesis of phytosterol oleate after reused 8 cycles, while free lipase was only viable for 5 batches with 90% esterification activity remained. Finally, the phytosterol oleate space time yield increased from 1.65g/L/h with free lipase to 2.53g/L/h with immobilized lipase. These results illustrate that the immobilized Yarrowia lipolytica lipase Ylip2 in a water activity controlled reactor has great potential for the application in phytosterol esters synthesis. Copyright © 2016. Published by Elsevier B.V.

  6. Modulation of the transient receptor potential vanilloid channel TRPV4 by 4alpha-phorbol esters: a structure-activity study

    DEFF Research Database (Denmark)

    Klausen, Thomas Kjaer; Pagani, Alberto; Minassi, Alberto

    2009-01-01

    The mechanism of activation of the transient receptor potential vanilloid 4 (TRPV4) channel by 4alpha-phorbol esters was investigated by combining information from chemical modification of 4alpha-phorbol-didecanoate (4alpha-PDD, 2a), site-directed mutagenesis, Ca(2+) imaging, and electrophysiology....... Binding of 4alpha-phorbol esters occurs in a loop in the TM3-TM4 domain of TRPV4 that is analogous to the capsaicin binding site of TRPV1, and the ester decoration of ring C and the A,B ring junction are critical for activity. The lipophilic ester groups on ring C serve mainly as a steering element...

  7. Antifungal and antioxidant activity of fatty acid methyl esters from vegetable oils

    Directory of Open Access Journals (Sweden)

    MARIA E.A. PINTO

    2017-08-01

    Full Text Available ABSTRACT Fatty acid methyl esters (FAMEs were obtained from vegetable oils of soybean, corn and sunflower. The current study was focused on evaluating the antifungal activity of FAMEs mainly against Paracoccidioides spp., as well as testing the interaction of these compounds with commercial antifungal drugs and also their antioxidant potential. FAMEs presented small IC50 values (1.86-9.42 μg/mL. All three FAMEs tested showed antifungal activity against isolates of Paracoccidioides spp. with MIC values ranging from 15.6-500 µg/mL. Sunflower FAMEs exhibited antifungal activity that extended also to other genera, with an MIC of 15.6 μg/mL against Candida glabrata and C. krusei and 31.2 μg/mL against C. parapsilosis. FAMEs exhibited a synergetic effect with itraconazole. The antifungal activity of the FAMEs against isolates of Paracoccidioides spp. is likely due to the presence of methyl linoleate, the major compound present in all three FAMEs. The results obtained indicate the potential of FAMEs as sources for antifungal and antioxidant activity.

  8. ELEVATED CHOLESTERYL ESTER TRANSFER PROTEIN-ACTIVITY IN IDDM MEN WHO SMOKE - POSSIBLE FACTOR FOR UNFAVORABLE LIPOPROTEIN PROFILE

    NARCIS (Netherlands)

    DULLAART, RPF; GROENER, JEM; DIKKESCHEI, BD; ERKELENS, DW; DOORENBOS, H

    Objectives: To determine the effect of cigarette smoking on the activity of cholesteryl ester transfer protein (CETP) and high-density (HDL), low-density (LDL), and very-low-density (VLDL) lipoproteins in insulin-dependent diabetic (IDDM) men with microvascular complications. Research Design and

  9. Catalytic Ester and Amide to Amine Interconversion: Nickel-Catalyzed Decarbonylative Amination of Esters and Amides by C−O and C−C Bond Activation

    KAUST Repository

    Yue, Huifeng

    2017-03-15

    An efficient nickel-catalyzed decarbonylative amination reaction of aryl and heteroaryl esters has been achieved for the first time. The new amination protocol allows the direct interconversion of esters and amides into the corresponding amines and represents a good alternative to classical rearrangements as well as cross coupling reactions.

  10. Catalytic Ester and Amide to Amine Interconversion: Nickel-Catalyzed Decarbonylative Amination of Esters and Amides by C−O and C−C Bond Activation

    KAUST Repository

    Yue, Huifeng; Guo, Lin; Liao, Hsuan-Hung; Cai, Yunfei; Zhu, Chen; Rueping, Magnus

    2017-01-01

    An efficient nickel-catalyzed decarbonylative amination reaction of aryl and heteroaryl esters has been achieved for the first time. The new amination protocol allows the direct interconversion of esters and amides into the corresponding amines and represents a good alternative to classical rearrangements as well as cross coupling reactions.

  11. Effect of external mass transfer on activation energy of butyl oleate ester synthesis using a whole cell bio catalyst

    International Nuclear Information System (INIS)

    Shahhoseini, Sh.; Nasernejad, B.; Vahabzadeh, F.

    2016-01-01

    In the present research, synthesis of butyl oleate ester from oleic acid and butanol using loofa-immobilized Rhizopus oryzae as a whole cell biocatalyst (LIC) was studied in which hexane was used as the hydrophobic solvent. Decrease of mass transfer limitations as result of the interface formation between the two immiscible substrates, positively affected on the reaction progress (87% as the ester product yielded within 10 h). By applying Arrhenius equation, the activation energy of the ester synthesis was determined as Ea=18.2 kJ/mol within temperature range of 15-45°C. It was notable to test appearance of the nonlinearity in Arrhenius plot which was indicative of presence of two sections. The reaction limited region was 15-35°C; Ea=27 kJ/mol and diffusion limited region was >35°C; Ea=6.8 kJ/mol. Eventually, in this research, influence of external mass transfer on activation energy with reference to the catalytic role of the LIC in the ester synthesis was discussed.

  12. Comparison of new nitrosoureas esters with modified steroidal nucleus for cytogenetic and antineoplastic activity.

    Science.gov (United States)

    Hussein, A; Mioglou-Kalouptsi, E; Papageorgiou, A; Karapidaki, I; Iakovidou-Kritsi, Z; Lialiaris, T; Xrysogelou, E; Camoutsis, C; Mourelatos, D

    2007-01-01

    Nitrosourea is decomposed under physiological conditions to react with biological macromolecules by two mechanisms: alkylation (with proteins and nucleic acids) and carbamoylation (with proteins but not nucleic acids). It has been suggested that the alkylating action is responsible for the therapeutic effects of nitrosoureas, and that the carbamoylation activity leads to toxicity effects. In order to reduce systemic toxicity and improve specificity and distribution for cancer therapy, 2-haloethyl nitrosourea has been esterified with modified steroids, which are used as biological platforms for transporting the alkylating agent to the tumor site in a specific manner. The cytogenetic and antineoplastic effect were studied of seven newly synthesized esters of N,N-bis(2-chloroethyl)alanyl carboxyl derivatives with a modified steroidal nucleus (compounds 1-7). As a very sensitive indicator of genotoxicity the Sister Chromatid Exchange (SCE) assay was used and as a valuable marker of cytostatic activity the cell Proliferation Rate Index (PRI) in cultures of normal human lymphocytes was used. The order of magnitude of the cytogenetic activity on a molar basis (15, 30, 120 microM) of the compounds was 7>6>3>5>2>4>1. The most active compound 7 has an enlarged (seven carbon atoms) A ring modified with a lactam group (-NHCO-) with the nitrosourea moiety esterified at position 17 In the group of seven substances a correlation was observed between the magnitude of SCE response and the depression in PRI (r=-O, 65, p6>2>5>4>3>1 and on lympocytic P388 leukemia cells is 7>2>6>5>4>3>1. The present results are in agreement with previous suggestions that the effectiveness in cytogenetic activity may well be correlated with antitumor effects [T/C: 248% for the compound 7 in 250 mg/kg b.w.; T/C: mean survival time of drug-treated animals (T) (excluding long term survivals) vs. corn-oil-treated controls (C)].

  13. Antiviral activity of shikonin ester derivative PMM-034 against enterovirus 71 in vitro

    Directory of Open Access Journals (Sweden)

    Y. Zhang

    2017-08-01

    Full Text Available Human enterovirus 71 (EV71 is the major causative agent of hand, foot, and mouth disease (HFMD, particularly in infants and children below 4 years of age. Shikonin is a bioactive compound with anti-inflammatory, antiviral, and antibacterial activities derived from the roots of the Chinese medicinal herb Lithospermum erythrorhizon. This study aimed to examine the antiviral activity of PMM-034, a shikonin ester derivative, against EV71 in rhabdomyosarcoma (RD cells. Cytotoxicity of PMM-034 on RD cells was determined using WST-1 assay. Dose- and time-dependent effects of PMM-034 on EV71 replication in RD cells were determined using plaque reduction assay. mRNA expression levels of EV71/VP1 and pro-inflammatory cytokines (IL-1β, IL-6, IL-8, and TNF-α were determined by real-time RT-PCR, and EV71/VP1 and phospho-p65 protein expressions were determined by western blot analysis. PMM-034 exhibited only weak cytotoxicity against RD cells. However, PMM-034 exhibited significant antiviral activity against EV71 in RD cells with 50% inhibitory concentration of 2.31 μg/mL. The VP1 mRNA and protein levels were significantly reduced in cells treated with PMM-034. Furthermore, relative mRNA expression levels of IL-1β, IL-6, IL-8, and TNF-α significantly decreased in the cells treated with PMM-034, while the phospho-p65 protein expression was also significantly lower in the treated cells. These results indicated that PMM-034 suppressed the expressions of pro-inflammatory cytokines in RD cells, exhibiting antiviral activity against EV71, as evidenced by the reduced VP1 mRNA and protein levels in PMM-034-treated cells. Thus, PMM-034 is a promising candidate for further development as an EV71 inhibitor.

  14. Replacement of Retinyl Esters by Polyunsaturated Triacylglycerol Species in Lipid Droplets of Hepatic Stellate Cells during Activation

    Science.gov (United States)

    Testerink, Nicole; Ajat, Mokrish; Houweling, Martin; Brouwers, Jos F.; Pully, Vishnu V.; van Manen, Henk-Jan; Otto, Cees; Helms, J. Bernd; Vaandrager, Arie B.

    2012-01-01

    Activation of hepatic stellate cells has been recognized as one of the first steps in liver injury and repair. During activation, hepatic stellate cells transform into myofibroblasts with concomitant loss of their lipid droplets (LDs) and production of excessive extracellular matrix. Here we aimed to obtain more insight in the dynamics and mechanism of LD loss. We have investigated the LD degradation processes in rat hepatic stellate cells in vitro with a combined approach of confocal Raman microspectroscopy and mass spectrometric analysis of lipids (lipidomics). Upon activation of the hepatic stellate cells, LDs reduce in size, but increase in number during the first 7 days, but the total volume of neutral lipids did not decrease. The LDs also migrate to cellular extensions in the first 7 days, before they disappear. In individual hepatic stellate cells. all LDs have a similar Raman spectrum, suggesting a similar lipid profile. However, Raman studies also showed that the retinyl esters are degraded more rapidly than the triacylglycerols upon activation. Lipidomic analyses confirmed that after 7 days in culture hepatic stellate cells have lost most of their retinyl esters, but not their triacylglycerols and cholesterol esters. Furthermore, we specifically observed a large increase in triacylglycerol-species containing polyunsaturated fatty acids, partly caused by an enhanced incorporation of exogenous arachidonic acid. These results reveal that lipid droplet degradation in activated hepatic stellate cells is a highly dynamic and regulated process. The rapid replacement of retinyl esters by polyunsaturated fatty acids in LDs suggests a role for both lipids or their derivatives like eicosanoids during hepatic stellate cell activation. PMID:22536341

  15. Replacement of retinyl esters by polyunsaturated triacylglycerol species in lipid droplets of hepatic stellate cells during activation.

    Directory of Open Access Journals (Sweden)

    Nicole Testerink

    Full Text Available Activation of hepatic stellate cells has been recognized as one of the first steps in liver injury and repair. During activation, hepatic stellate cells transform into myofibroblasts with concomitant loss of their lipid droplets (LDs and production of excessive extracellular matrix. Here we aimed to obtain more insight in the dynamics and mechanism of LD loss. We have investigated the LD degradation processes in rat hepatic stellate cells in vitro with a combined approach of confocal Raman microspectroscopy and mass spectrometric analysis of lipids (lipidomics. Upon activation of the hepatic stellate cells, LDs reduce in size, but increase in number during the first 7 days, but the total volume of neutral lipids did not decrease. The LDs also migrate to cellular extensions in the first 7 days, before they disappear. In individual hepatic stellate cells. all LDs have a similar Raman spectrum, suggesting a similar lipid profile. However, Raman studies also showed that the retinyl esters are degraded more rapidly than the triacylglycerols upon activation. Lipidomic analyses confirmed that after 7 days in culture hepatic stellate cells have lost most of their retinyl esters, but not their triacylglycerols and cholesterol esters. Furthermore, we specifically observed a large increase in triacylglycerol-species containing polyunsaturated fatty acids, partly caused by an enhanced incorporation of exogenous arachidonic acid. These results reveal that lipid droplet degradation in activated hepatic stellate cells is a highly dynamic and regulated process. The rapid replacement of retinyl esters by polyunsaturated fatty acids in LDs suggests a role for both lipids or their derivatives like eicosanoids during hepatic stellate cell activation.

  16. Antiviral and Virucidal Activities of N-Cocoyl-L-Arginine Ethyl Ester

    Directory of Open Access Journals (Sweden)

    Hisashi Yamasaki

    2011-01-01

    Full Text Available Various amino acid-derived compounds, for example, Nα-Cocoyl-L-arginine ethyl ester (CAE, alkyloxyhydroxylpropylarginine, arginine cocoate, and cocoyl glycine potassium salt (Amilite, were examined for their virucidal activities against herpes simplex virus type 1 and 2 (HSV-1 and HSV-2, influenza A virus (IAV, and poliovirus type 1 (PV-1 in comparison to benzalkonium chloride (BKC and sodium dodecylsulfate (SDS as a cationic and anionic control detergent and also to other commercially available disinfectants. While these amino acid-derived compounds were all effective against HSV-1 and HSV-2, CAE and Amilite were the most effective. These two compounds were, however, not as effective against IAV, another enveloped virus, as against HSV. Cytotoxicity of CAE was weak; at 0.012%, only 5% of the cells were killed under the conditions, in which 100% cells were killed by either SDS or BKC. In addition to these direct virucidal effects, CAE inhibited the virus growth in the HSV-1- or PV-1-infected cells even at 0.01%. These results suggest a potential application of CAE as a therapeutic or preventive medicine against HSV superficial infection at body surface.

  17. Two bifunctional enzymes from the marine protist Thraustochytrium roseum: biochemical characterization of wax ester synthase/acyl-CoA:diacylglycerol acyltransferase activity catalyzing wax ester and triacylglycerol synthesis.

    Science.gov (United States)

    Zhang, Nannan; Mao, Zejing; Luo, Ling; Wan, Xia; Huang, Fenghong; Gong, Yangmin

    2017-01-01

    Triacylglycerols (TAGs) and wax esters (WEs) are important neutral lipids which serve as energy reservoir in some plants and microorganisms. In recent years, these biologically produced neutral lipids have been regarded as potential alternative energy sources for biofuel production because of the increased interest on developing renewable and environmentally benign alternatives for fossil fuels. In bacteria, the final step in TAG and WE biosynthetic pathway is catalyzed by wax ester synthase/acyl coenzyme A (acyl-CoA):diacylglycerol acyltransferase (WS/DGAT). This bifunctional WS/DGAT enzyme is also a key enzyme in biotechnological production of liquid WE via engineering of plants and microorganisms. To date, knowledge about this class of biologically and biotechnologically important enzymes is mainly from biochemical characterization of WS/DGATs from Arabidopsis, jojoba and some bacteria that can synthesize both TAGs and WEs intracellularly, whereas little is known about WS/DGATs from eukaryotic microorganisms. Here, we report the identification and characterization of two bifunctional WS/DGAT enzymes (designated TrWSD4 and TrWSD5) from the marine protist Thraustochytrium roseum . Both TrWSD4 and TrWSD5 comprise a WS-like acyl-CoA acyltransferase domain and the recombinant proteins purified from Escherichia coli Rosetta (DE3) have substantial WS and lower DGAT activity. They exhibit WS activity towards various-chain-length saturated and polyunsaturated acyl-CoAs and fatty alcohols ranging from C 10 to C 18 . TrWSD4 displays WS activity with the lowest K m value of 0.14 μM and the highest k cat / K m value of 1.46 × 10 5  M -1  s -1 for lauroyl-CoA (C 12:0 ) in the presence of 100 μM hexadecanol, while TrWSD5 exhibits WS activity with the lowest K m value of 0.96 μM and the highest k cat / K m value of 9.83 × 10 4  M -1  s -1 for decanoyl-CoA (C 10:0 ) under the same reaction condition. Both WS/DGAT enzymes have the highest WS activity at 37 and 47

  18. Study of surface activity of piroxicam at the interface of palm oil esters and various aqueous phases.

    Science.gov (United States)

    Abdulkarim, Muthanna Fawzy; Abdullah, Ghassan Zuhair; Chitneni, Mallikarjun; Yam, Mun Fei; Mahdi, Elrashid Saleh; Salman, Ibrahim Muhammad; Ameer, Omar Ziad; Sattar, Munavvar Abdul; Basri, Mahiran; Noor, Azmin Mohd

    2012-04-01

    The surface activity of some non-steroidal anti-inflammatory agents like ibuprofen was investigated extensively. This fact has attracted the researchers to extend this behavior to other agents like piroxicam. Piroxicam molecules are expected to orient at the interface of oil and aqueous phase. The aim of this study was, firstly, to assess the surface and interfacial tension behaviour of newly synthesised palm oil esters and various pH phosphate buffers. Furthermore, the surface and interfacial tension activity of piroxicam was studied. All the measurements of surface and interfacial tension were made using the tensiometer. The study revealed that piroxicam has no effect on surface tension values of all pH phosphate buffers and palm oil esters. Similarly, various concentrations of piroxicam did not affect the interfacial tensions between the oil phase and the buffer phases. Accordingly, the interfacial tension values of all mixtures of oil and phosphate buffers were considerably high which indicates the immiscibility. It could be concluded that piroxicam has no surface activity. Additionally, there is no surface pressure activity of piroxicam at the interface of plam oil esters and phosphate buffers in the presence of Tweens and Spans.

  19. Synthesis of carbonate esters by carboxymethylation using NaAlO2 as a highly active heterogeneous catalyst

    OpenAIRE

    Ramesh, Sreerangappa; Indukuri, Kiran; Riant, Olivier; Debecker, Damien

    2018-01-01

    Sodium aluminate is presented as a highly active heterogeneous catalyst able to convert a range of alcohols into the corresponding mixed carbonate esters, in high yield and under green conditions. The reaction is carried out using dimethyl carbonate both as a reactant and solvent, at 90°C. Allylic, aliphatic and aromatic alcohols are converted in good yields. The solid catalyst is shown to be truly heterogeneous, resistant to leaching, and recyclable.

  20. The human receptor for urokinase plasminogen activator. NH2-terminal amino acid sequence and glycosylation variants

    DEFF Research Database (Denmark)

    Behrendt, N; Rønne, E; Ploug, M

    1990-01-01

    -PA. The purified protein shows a single 55-60 kDa band after sodium dodecyl sulfate-polyacrylamide gel electrophoresis and silver staining. It is a heavily glycosylated protein, the deglycosylated polypeptide chain comprising only 35 kDa. The glycosylated protein contains N-acetyl-D-glucosamine and sialic acid......, but no N-acetyl-D-galactosamine. Glycosylation is responsible for substantial heterogeneity in the receptor on phorbol ester-stimulated U937 cells, and also for molecular weight variations among various cell lines. The amino acid composition and the NH2-terminal amino acid sequence are reported...

  1. Recycling of CR1 by phorbol ester-activated polymorphonuclear leukocytes (PMN)

    International Nuclear Information System (INIS)

    Malbran, A.; Frank, M.M.; Fries, L.

    1986-01-01

    PMN CR1 is internalized when these cells are stimulated with phorbol esters. To elucidate the fate of these receptors and ligand bound to them, the authors studied the uptake and disposition of 125 I-C3b by phorbol dibutyrate (PDBu)-treated PMN. C3b monomers bind to PDBu-treated PMN with a K(d) of 4.75 +/- 1.06 x 1 -8 M at 0 0 C in reduced ionic strength. This C3b remains almost entirely dissociable by high ionic strength buffer unless the cells are warmed. At 37 0 C, PDBu-treated PMN internalize monomer C3b into a non-strippable pool, reaching a plateau level of approx. 50% of bound ligand. Exocytosis of the internalized C3b was studied by washing the PMN in cold PBS, then rewarming to 37 0 . A progressive release of internalized C3b is observed, with kinetics similar to internalization and reaching a plateau of 48 +/- 4.2% at 15 minutes. Released C3b is precipitable by 10% TCA, suggesting that release does not require passage through the lysosomal compartment. PMN preloaded with 1mM chloroquine behave identically in the exocytosis phase, supporting this hypothesis. The non-recycling pool of 125 I-C3b is stable for at least 30 minutes at 37 0 . Uptake of chemically cross-linked C3b dimers by PMN is followed by slower and less complete exocytosis of internal counts, suggesting diversion into the non-releaseable pool. Activated PMN CR1 is partially recycled via a prelysosomal compartment. Minimal cross-linking shifts receptor-ligand complexes into a non-recycling, possibly lysosomal, pool

  2. Effect of 17alpha-ethinylestradiol on activity of rat liver enzymes for synthesis and hydrolysis of cholesterol esters

    International Nuclear Information System (INIS)

    Nikitin, Yu.P.; Dushkin, M.I.; Dolgov, A.V.; Gordienko, I.A.

    1987-01-01

    Administration of estrogens is known to lower the concentration of cholesterol esters in the blood vessel wall and may delay the development of arteriosclerosis. It is also known that under the influence of estrogens the redistribution of concentrations of free cholesterol and cholesterol esters takes place in rats between the blood and liver as a result of the intensification of receptor-dependent uptake of low-density lipoproteins by the hepatocytes. The mechanisms of this intracellular redistribution, however, have been inadequately studied. The purpose of this paper is to study the effects of 17alpha-ethinylestradiol on the activity of lysosomal and cytoplasmic cholesterol esterases, acyl-CoA-cholesterol-O-acyltransferase, lysosomal acid phosphatase, and beta-D-galactosidase. The activity was measured by using cholesterol [1-C 14]-oleate as the substrate. The influence of the estradiol is found to be based on cholesterol redistribution between the blood and liver. Accumulation of free cholesterol in the liver under these conditions stimulates bile acid formation. Depression of cholesterol ester synthesis as a result of direct inhibition of the acyltransferase by the estradiol is found to possibly contribute to the fall in the cholesterol level in the body. Liquid scintillation counting was used to measure distribution and accumulation

  3. Stability profile of flavour-active ester compounds in ale and lager ...

    African Journals Online (AJOL)

    User

    2013-01-30

    Jan 30, 2013 ... Currently, one of the main quality problems of beer is the change of its chemical composition during storage, which alters its sensory properties. In this study, ale and lager beers were produced and aged for three months at two storage temperatures. Concentration of volatile ester compounds (VECs) in the.

  4. Angiogenin activates phospholipase C and elicits a rapid incorporation of fatty acid into cholesterol esters in vascular smooth muscle cells

    International Nuclear Information System (INIS)

    Moore, F.; Riordan, J.F.

    1990-01-01

    Angiogenin activates the phosphoinositide-specific phospholipase C (PLC) in cultured rat aortic smooth muscle cells to yield a transient (30 s) peak of 1,2-diacylglycerol (DG) and inositol trisphosphate. Within 1 min, the DG level falls below that of the control and remains so for at least 20 min. A transient increase in monoacylglycerol indicates that depletion of DG may be the consequence of hydrolysis by DG lipase. In addition to these changes in second messengers, a rapid increase in incorporating of radiolabeled tracer into cellular cholesterol esters is observed. Stimulated cholesterol ester labeling is inhibited by preincubation with either the DG lipase inhibitor RHC 80267 or the acyl coenzyme A:cholesterol acyltransferase inhibitor Sandoz 58035. Cells prelabeled with [ 3 H]arachidonate show a sustained increase in labeling of cholesterol esters following exposure to angiogenin. In contrast, cells prelabeled with [ 3 H]oleate show only a transient elevation that returns to the basal level by 5 min. This suggests initial cholesterol esterification by oleate followed by arachidonate that is released by stimulation of the PLC/DG lipase pathway

  5. Transesterification of mustard (Brassica nigra) seed oil with ethanol: Purification of the crude ethyl ester with activated carbon produced from de-oiled cake

    International Nuclear Information System (INIS)

    Fadhil, Abdelrahman B.; Abdulahad, Waseem S.

    2014-01-01

    Highlights: • Biodiesel ethyl ester has been developed from mustard seed oil. • Variables affect the transesterification were investigated. • Dry washing using the activated carbon produced from the extraction remaining was applied to purify the ethyl esters. • Properties of the produced fuels were measured. • Blending of the produced ethyl ester with petro diesel was also investigated. - Abstract: The present study reports the production of mustard seed oil ethyl esters (MSOEE) through alkali-catalyzed transesterification with ethanol using potassium hydroxide as a catalyst. The influence of the process parameters such as catalyst concentration, ethanol to oil molar ratio, reaction temperature, reaction duration and the catalyst type was investigated so as to find out the optimal conditions for the transesterification process. As a result, optimum conditions for production of MSOEE were found to be: 0.90% KOH wt/wt of oil, 8:1 ethanol to oil molar ratio, a reaction temperature of 60 °C, and a reaction time of 60 min. Dry washing method with (2.50% wt.) of the activated carbon that was produced from the de-oiled cake was used to purify the crude ethyl ester from the residual catalyst and glycerol. The transesterification process provided a yield of 94% w/w of ethyl esters with an ester content of 98.22% wt. under the optimum conditions. Properties of the produced ethyl esters satisfied the specifications prescribed by the ASTM standards. Blending MSOEE with petro diesel was also investigated. The results showed that the ethyl esters had a slight influence on the properties of petro diesel

  6. Synthesis and Proapoptotic Activity on Cervical Cancer Cell of Ester Eugenol 1-(3-Methoxy-4-hydroxy)phenyl-2-propylmethanoate

    Science.gov (United States)

    Farid Rahman, Moh.; Nazhif Haykal, Muhammad; Andriani Siagian, Novi; Maiselina Sriepindonnta, Priscilla; Tampubolon, Norman Alexander

    2018-01-01

    Proapoptotic activity of ester eugenol,1-(3-methoxy-4-hydroxy)phenyl-2-propylmethanoat, which synthesized from eugenol is reported. Eugenol as starting material in the synthesis of ester eugenol was obtained from fractional distillation of clove oil with the yield of 70.66%. Synthesis of ester eugenol was camed out by addition-esterification reaction through reaction between eugenol and formic acid with mol ratio of 1:27 and reaction time for11 h. GC-MS analysis showed ester eugenol was afforded purity of 92.42% and the yield in of 93.34%. UV spectra of ester eugenol was observed the formation of carbonyl group at λmax 290 nm and supported by FT-IR analysis at 1714.60 cm-1 (carbonyl group), 1193.65 cm-1 (C-O-C ester group) and the absence of vynil group in eugenol structure at region 914.20 and 995.20 cm-1. Mass spectra showed ion molecule at m/z 210 was accordance with molecular weight of ester eugenol. Afterward, HeLa cell culture media was prepared for cervical cancer antiproliferative test. The result which showed in histogram indicated that LC50 of ester eugenol was reached at concentration below 0.01% while eugenol was up to 0.01% that observed cervical cancer cell apoptotic activity. LC50 value of ester eugenol was obtained at concentration 48.73 ppm. This research reported that natural product modified its structure has potency to cure cervical cancer.

  7. Synthesis of Amide and Ester Derivatives of Cinnamic Acid and Its Analogs: Evaluation of Their Free Radical Scavenging and Monoamine Oxidase and Cholinesterase Inhibitory Activities.

    Science.gov (United States)

    Takao, Koichi; Toda, Kazuhiro; Saito, Takayuki; Sugita, Yoshiaki

    2017-01-01

    A series of cinnamic acid derivatives, amides (1-12) and esters (13-22), were synthesized, and structure-activity relationships for antioxidant activity, and monoamine oxidases (MAO) A and B, acetylcholinesterase, and butyrylcholinesterase (BChE) inhibitory activities were analyzed. Among the synthesized compounds, compounds 1-10, 12-18, and rosmarinic acid (23), which contained catechol, o-methoxyphenol or 5-hydroxyindole moieties, showed potent 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity. Compounds 9-11, 15, 17-22 showed potent and selective MAO-B inhibitory activity. Compound 20 was the most potent inhibitor of MAO-B. Compounds 18 and 21 showed moderate BChE inhibitory activity. In addition, compound 18 showed potent antioxidant activity and MAO-B inhibitory activity. In a comparison of the cinnamic acid amides and esters, the amides exhibited more potent DPPH free radical scavenging activity, while the esters showed stronger inhibitory activities against MAO-B and BChE. These results suggested that cinnamic acid derivatives such as compound 18, p-coumaric acid 3,4-dihydroxyphenethyl ester, and compound 20, p-coumaric acid phenethyl ester, may serve as lead compounds for the development of novel MAO-B inhibitors and candidate lead compounds for the prevention or treatment of Alzheimer's disease.

  8. Synthesis and Antimicrobial Activity of 2-(Aminoacid ester)-3-(6 ...

    African Journals Online (AJOL)

    NJD

    2008-11-06

    Nov 6, 2008 ... synthesized new 6-membered heterocycles in which aminoacid esters are linked to the phosphorus .... analysis run in a 3:7 mixture of ethyl acetate and hexane and the average Rf value observed was 0.75. ..... 7 K.G. Devine, C. McGuigan, T.J. O'Connor, S.R. Nicholis and. D. Kinchington, AIDS, 1990, 4, ...

  9. Role of sulfate ester in influencing biological activity of cholecystokinin-related peptides

    International Nuclear Information System (INIS)

    Vinayek, R.; Jensen, R.T.; Gardner, J.D.

    1987-01-01

    In dispersed acini from guinea pig, mouse, or rat pancreas cholecystokinin-(27-33) is a full agonist, and removing the sulfate ester from the tyrosine residue in position 27 caused a 100- to 300-fold decrease in potency with no change in efficacy. In dispersed acini from mouse or rat pancreas, cholecystokinin-(27-32)-NH 2 is a partial agonist, and removing the sulfate ester from the tyrosine in position 27 abolished the efficacy. The desulfated peptide was able, however, to interact with [ 125 I] CCK receptors with a potency that was threefold less than that of cholecystokinin-(27-32)-NH 2 and therefore functioned as a cholecystokinin receptor antagonist. In dispersed acini from guinea pig pancreas cholecystokinin-(27-32)-NH 2 is a cholecystokinin receptor antagonist. Removing the sulfate ester from the tyrosine residue in position 27 of cholecystokinin-(27-32)-NH 2 caused a fourfold decrease in potency but did not abolish the ability of the peptide to interact with cholecystokinin receptors; therefore, desulfated cholecystokinin-(27-32)-NH 2 functioned as a cholecystokinin receptor antagonist

  10. 1,2-Diacylglycerols, but not phorbol esters, activate a potential inhibitory pathway for protein kinase C in GH3 pituitary cells. Evidence for involvement of a sphingomyelinase.

    Science.gov (United States)

    Kolesnick, R N; Clegg, S

    1988-05-15

    It has been suggested that sphingoid bases may serve as physiologic inhibitors of protein kinase C. Because 1,2-diacylglycerols, but not phorbol esters, enhance sphingomyelin degradation via a sphingomyelinase in GH3 pituitary cells (Kolesnick, R. N. (1987) J. Biol. Chem. 262, 16759-16762), the effects of phorbol esters, 1,2-diacylglycerols, and sphingomyelinase on protein kinase C activation were assessed. Under basal conditions, the inactive cytosolic form of protein kinase C predominated. 1,2-Diacylglycerols stimulated transient protein kinase C redistribution to the membrane. 1,2-Dioctanoylglycerol (200 micrograms/ml) reduced cytosolic protein kinase C activity to 67% of control from 72 to 48 pmol.min-1.10(6) cells-1 and enhanced membrane-bound activity to 430% of control from 6 to 25 pmol.min-1.10(6) cells-1 after 4 min of stimulation. Thereafter, protein kinase C activity returned to the cytosol. In contrast, the phorbol ester, 12-O-tetradecanoylphorbol-13-acetate (TPA), stimulated redistribution to the membrane without return to the cytosol. Exogenous sphingomyelinase reduced membrane-bound protein kinase C activity to 30% of control, yet did not alter cytosolic activity. Sphingomyelinase, added after phorbol ester-induced redistribution was completed, restored activity to the cytosol. In these studies, TPA (10(-8) M) reduced cytosolic activity to 62% of control and elevated membrane-bound protein kinase C activity to 650% of control. Sphingomyelinase restored cytosolic activity to 84% of control and reduced membrane-bound activity to 297% of control. Similarly, the free sphingoid bases, sphingosine, sphinganine, and phytosphingosine, reversed phorbol ester-induced protein kinase C redistribution. Since 1,2-diacylglycerols activate a sphingomyelinase and sphingomyelinase action can reverse protein kinase C activation, these studies suggest that a pathway involving a sphingomyelinase might comprise a physiologic negative effector system for protein kinase C

  11. Structure-activity relationship of pentacylic triterpene esters from Uncaria rhynchophylla as inhibitors of phospholipase Cgamma1.

    Science.gov (United States)

    Lee, Ji Suk; Yoo, Hunseung; Suh, Young Ger; Jung, Jae Kyung; Kim, Jinwoong

    2008-10-01

    A systematic structure-activity relationship of 3beta-hydroxy-27- P- E-coumaroyloxyurs-12-en-28-oic acid ( 7), a triterpene ester isolated from UNCARIA RHYNCHOPHYLLA as a phospholipase Cgamma1 inhibitor, was undertaken with a view toward elucidating its chemical mode of action on PLCgamma1. Related derivatives and analogues of 7 were synthesized and their inhibitory activities against PLCgamma1 were evaluated IN VITRO. The results indicate that 3-OH and 27-esterification may be essential, and that 28-COOH and the 2' double bond appear to be important for activity. Furthermore, the compound possessing a P-coumaroyloxy at position 27 rather than at the 3 and 28 positions shows the greatest inhibitory activity against PLCgamma1. Therefore, this inhibitor will be providing a chemical lead for the further development of cancer chemopreventive or cancer chemotherapeutic agents that have lower toxicity against normal tissues.

  12. Activities of four bus terminals of Semarang City gateway and the related GHG emission

    Science.gov (United States)

    Huboyo, H. S.; Wardhana, I. W.; Sutrisno, E.; Wangi, L. S.; Lina, R. A.

    2018-01-01

    The activities of the bus terminal, including loading-unloading passengers, bus idling, and bus movements at the terminal, will emit GHG’s emission. This research analyzes GHG emission from four terminals, i.e., Mangkang, Terboyo, Penggaron, and Sukun in Semarang City. The emission was estimated by observing detail activities of public transport means, especially for moving and idling time. The emission was calculated by Tier 2 method based on the vehicle type as well as fuel consumption. The highest CO2e during vehicle movements at Sukun area was contributed by large bus about 2.08 tons/year, while at Terboyo terminal was contributed by medium bus about 347.97 tons/year. At Mangkang terminals, the highest emission for vehicle movements was attributed by medium bus as well of about 53.18 tons/year. At last, Penggaron terminal’s highest GHG emission was attributed by BRT about 26.47 tons/year. During idling time, the highest contributor to CO2e was the large bus at the three terminals, i.e., Sukun of 43.53 tons/year, Terboyo of 196.56 tons/year, and Mangkang of 84.26 tons/year, while at Penggaron, BRT dominated with CO2e of 26.47 tons/year. The management of public transport in terminals is crucial to mitigate the emission related to bus terminals activities.

  13. Thymoquinone inhibits phorbol ester-induced activation of NF-κB and expression of COX-2, and induces expression of cytoprotective enzymes in mouse skin in vivo

    International Nuclear Information System (INIS)

    Kundu, Joydeb Kumar; Liu, Lijia; Shin, Jun-Wan; Surh, Young-Joon

    2013-01-01

    Highlights: •Thymoquinone inhibits phorbol ester-induced COX-2 expression in mouse skin. •Thymoquinone attenuates phosphorylation of IκBα and DNA binding of NF-κB in mouse skin. •Thymoquinone inhibits phosphorylation of p38 MAP kinase, JNK and Akt in mouse skin. •Thymoquinone induces the expression of cytoprotective proteins in mouse skin. -- Abstract: Thymoquinone (TQ), the active ingredient of Nigella sativa, has been reported to possess anti-inflammatory and chemopreventive properties. The present study was aimed at elucidating the molecular mechanisms of anti-inflammatory and antioxidative activities of thymoquinone in mouse skin. Pretreatment of female HR-1 hairless mouse skin with TQ attenuated 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced expression of cyclooxygenase-2 (COX-2). TQ diminished nuclear translocation and the DNA binding of nuclear factor-kappaB (NF-κB) via the blockade of phosphorylation and subsequent degradation of IκBα in TPA-treated mouse skin. Pretreatment with TQ attenuated the phosphorylation of Akt, c-Jun-N-terminal kinase and p38 mitogen-activated protein kinase, but not that of extracellular signal-regulated kinase-1/2. Moreover, topical application of TQ induced the expression of heme oxygenase-1, NAD(P)H-quinoneoxidoreductase-1, glutathione-S-transferase and glutamate cysteine ligase in mouse skin. Taken together, the inhibitory effects of TQ on TPA-induced COX-2 expression and NF-κB activation, and its ability to induce the expression of cytoprotective proteins provide a mechanistic basis of anti-inflammatory and antioxidative effects of TQ in hairless mouse skin

  14. Larvicidal activity of oils, fatty acids, and methyl esters from ripe and unripe fruit of Solanum lycocarpum (Solanaceae against the vector Culex quinquefasciatus (Diptera: Culicidae

    Directory of Open Access Journals (Sweden)

    Viviane de Cássia Bicalho Silva

    2015-10-01

    Full Text Available ABSTRACTINTRODUCTION:The larvicidal activity of oils, fatty acids, and methyl esters of Solanum lycocarpum fruit against Culex quinquefasciatus is unknown.METHODS:The larvicidal activity of samples of ripe and unripe fruit from S. lycocarpum was evaluated against third and fourth instar larvae of C. quinquefasciatus .RESULTS:The oils, fatty acids, and methyl esters of S. lycocarpum showed the greatest larvicidal effect (57.1-95.0% at a concentration of 100mg/L (LC 50values between 0.70 and 27.54mg/L.CONCLUSIONS:Solanum lycocarpum fruit may be a good source of new natural products with larvicidal activity.

  15. Global Modeling of Microwave Three Terminal Active Devices Using the FDTD Method

    National Research Council Canada - National Science Library

    Mrabet, O. E; Essaaidi, M; Drissi, M'hamed

    2005-01-01

    This paper presents a new approach for the global electromagnetic analysis of the three-Terminal active linear and nonlinear microwave circuits using the Finite-Difference Time Domain (FDTD) Method...

  16. Comparison of Antioxidant Evaluation Assays for Investigating Antioxidative Activity of Gallic Acid and Its Alkyl Esters in Different Food Matrices.

    Science.gov (United States)

    Phonsatta, Natthaporn; Deetae, Pawinee; Luangpituksa, Pairoj; Grajeda-Iglesias, Claudia; Figueroa-Espinoza, Maria Cruz; Le Comte, Jérôme; Villeneuve, Pierre; Decker, Eric A; Visessanguan, Wonnop; Panya, Atikorn

    2017-08-30

    The addition of antioxidants is one of the strategies to inhibit lipid oxidation, a major cause of lipid deterioration in foods leading to rancidity development and nutritional losses. However, several studies have been reported that conventional antioxidant assays, e.g., TPC, ABTS, FRAP, and ORAC could not predict antioxidant performance in several foods. This study aimed to investigate the performance of two recently developed assays, e.g., the conjugated autoxidizable triene (CAT) and the apolar radical-initiated conjugated autoxidizable triene (ApoCAT) assays to predict the antioxidant effectiveness of gallic acid and its esters in selected food models in comparison with the conventional antioxidant assays. The results indicated that the polarities of the antioxidants have a strong impact on antioxidant activities. In addition, different oxidant locations demonstrated by the CAT and ApoCAT assays influenced the overall antioxidant performances of the antioxidants with different polarities. To validate the predictability of the assays, the antioxidative performance of gallic acid and its alkyl esters was investigated in oil-in-water (O/W) emulsions, bulk soybean oils, and roasted peanuts as the lipid food models. The results showed that only the ApoCAT assay could be able to predict the antioxidative performances in O/W emulsions regardless of the antioxidant polarities. This study demonstrated that the relevance of antioxidant assays to food models was strongly dependent on physical similarities between the tested assays and the food structure matrices.

  17. Conversion of amides to esters by the nickel-catalysed activation of amide C-N bonds.

    Science.gov (United States)

    Hie, Liana; Fine Nathel, Noah F; Shah, Tejas K; Baker, Emma L; Hong, Xin; Yang, Yun-Fang; Liu, Peng; Houk, K N; Garg, Neil K

    2015-08-06

    Amides are common functional groups that have been studied for more than a century. They are the key building blocks of proteins and are present in a broad range of other natural and synthetic compounds. Amides are known to be poor electrophiles, which is typically attributed to the resonance stability of the amide bond. Although amides can readily be cleaved by enzymes such as proteases, it is difficult to selectively break the carbon-nitrogen bond of an amide using synthetic chemistry. Here we demonstrate that amide carbon-nitrogen bonds can be activated and cleaved using nickel catalysts. We use this methodology to convert amides to esters, which is a challenging and underdeveloped transformation. The reaction methodology proceeds under exceptionally mild reaction conditions, and avoids the use of a large excess of an alcohol nucleophile. Density functional theory calculations provide insight into the thermodynamics and catalytic cycle of the amide-to-ester transformation. Our results provide a way to harness amide functional groups as synthetic building blocks and are expected to lead to the further use of amides in the construction of carbon-heteroatom or carbon-carbon bonds using non-precious-metal catalysis.

  18. Fabrication, Rheology and Antioxidant Activity of Palm Esters-based Emulsions Loaded with Tocotrienol

    Directory of Open Access Journals (Sweden)

    S.H NG

    2014-06-01

    The yield stress of the emulsions increased with increasing acoustic amplitudes. The viscoelasticity of the emulsions were enhanced by the increase in the oil and surfactant concentrations. The emulsions with higher oil phase concentration [30% (w/w] showed greater elasticity which implied strong dynamic rigidity of the emulsions. The cohesive energy increased significantly with surfactant concentration especially for the emulsions with 30% (w/w oil phase concentration. The palm oil esters emulsions containing tocotrienol gave higher Trolox equivalent antioxidant capacity values which implied higher antioxidant capability. The tocotrienol in emulsion with 30% (w/w dispersed phase showed that they were the most stable with longest shelf life and exhibited greater inhibitory effects on the ABTS".

  19. Cytotoxicity of Endoperoxides from the Caribbean Sponge Plakortis halichondrioides towards Sensitive and Multidrug-Resistant Leukemia Cells: Acids vs. Esters Activity Evaluation

    Directory of Open Access Journals (Sweden)

    Tanja Schirmeister

    2017-03-01

    Full Text Available The 6-epimer of the plakortide H acid (1, along with the endoperoxides plakortide E (2, plakortin (3, and dihydroplakortin (4 have been isolated from a sample of the Caribbean sponge Plakortis halichondrioides. To perform a comparative study on the cytotoxicity towards the drug-sensitive leukemia CCRF-CEM cell line and its multi-drug resistant subline CEM/ADR5000, the acid of plakortin, namely plakortic acid (5, as well as the esters plakortide E methyl ester (6 and 6-epi-plakortide H (7 were synthesized by hydrolysis and Steglich esterification, respectively. The data obtained showed that the acids (1, 2, 5 exhibited potent cytotoxicity towards both cell lines, whereas the esters showed no activity (6, 7 or weaker activity (3, 4 compared to their corresponding acids. Plakortic acid (5 was the most promising derivative with half maximal inhibitory concentration (IC50 values of ca. 0.20 µM for both cell lines.

  20. The impact of the human DNA topoisomerase II C-terminal domain on activity.

    Directory of Open Access Journals (Sweden)

    Emma L Meczes

    2008-03-01

    Full Text Available Type II DNA topoisomerases (topos are essential enzymes needed for the resolution of topological problems that occur during DNA metabolic processes. Topos carry out an ATP-dependent strand passage reaction whereby one double helix is passed through a transient break in another. Humans have two topoII isoforms, alpha and beta, which while enzymatically similar are differentially expressed and regulated, and are thought to have different cellular roles. The C-terminal domain (CTD of the enzyme has the most diversity, and has been implicated in regulation. We sought to investigate the impact of the CTD domain on activity.We have investigated the role of the human topoII C-terminal domain by creating constructs encoding C-terminally truncated recombinant topoIIalpha and beta and topoIIalpha+beta-tail and topoIIbeta+alpha-tail chimeric proteins. We then investigated function in vivo in a yeast system, and in vitro in activity assays. We find that the C-terminal domain of human topoII isoforms is needed for in vivo function of the enzyme, but not needed for cleavage activity. C-terminally truncated enzymes had similar strand passage activity to full length enzymes, but the presence of the opposite C-terminal domain had a large effect, with the topoIIalpha-CTD increasing activity, and the topoIIbeta-CTD decreasing activity.In vivo complementation data show that the topoIIalpha C-terminal domain is needed for growth, but the topoIIbeta isoform is able to support low levels of growth without a C-terminal domain. This may indicate that topoIIbeta has an additional localisation signal. In vitro data suggest that, while the lack of any C-terminal domain has little effect on activity, the presence of either the topoIIalpha or beta C-terminal domain can affect strand passage activity. Data indicates that the topoIIbeta-CTD may be a negative regulator. This is the first report of in vitro data with chimeric human topoIIs.

  1. Basal-bolus insulin therapy reduces maternal triglycerides in gestational diabetes without modifying cholesteryl ester transfer protein activity.

    Science.gov (United States)

    Olmos, Pablo R; Borzone, Gisella R

    2017-09-01

    Macrosomia in the offspring of overweight/obese mothers with glucose-controlled gestational diabetes mellitus (GDM) is due to excessive rise of maternal triglycerides (TG). We aimed to ascertain whether basal-bolus insulin therapy (BBIT), or other components of the treatment, could reduce TG in GDM. We studied the records of 131 singleton pregnancies with GDM, using stepwise multiple linear regression, Mann-Whitney, χ 2 , and Jonckheere-Terpstra tests. As maternal TG increased steadily during normal pregnancy, these were transformed as z-scores. The atherogenic index of plasma (AIP) was calculated as a measure of cholesteryl ester transfer protein activity. Multiple regression showed that only BBIT (but neither limitation of weight gain nor metformin) reduced maternal TG z-scores (P = 0.011). When the 131 pregnancies were split into two groups - without BBIT (n = 58; HbA1c = 5.3 ± 0.3%) and with BBIT (n = 73; HbA1c = 5.4 ± 0.6; P = 0.2005) - we observed that BBIT (n = 73) reduced maternal TG z-scores in a dose-related fashion (Jonckheere-Terpstra P = 0.03817). The atherogenic index of plasma remained within normal range in both groups. BBIT (but not weight gain control nor metformin) reduced maternal TG in mothers with glucose-controlled GDM. This beneficial effect of BBIT was not related to changes in the cholesteryl ester transfer protein activity. © 2017 Japan Society of Obstetrics and Gynecology.

  2. Impedance Characteristics Modeling of a Two-Terminal Active Capacitor

    DEFF Research Database (Denmark)

    Wang, Haoran; Wang, Huai; Lu, Minghui

    2017-01-01

    to overcome the above issues. In this paper, the modeling of the active capacitor is investigated and a voltage feed-forward compensation scheme is proposed for overshoot reduction. Therefore, the impedance, equivalent capacitance, ESR, and ESL, of the active capacitor can be specified. A case study based...

  3. Synthesis, DFT and antimicrobial activity assays in vitro for novel cis/trans-but-2-enedioic acid esters

    Science.gov (United States)

    Ma, Yan-Long; Zhou, Ru-Jin; Zeng, Xing-Ye; An, Ya-Xiong; Qiu, Song-Shan; Nie, Li-Jun

    2014-04-01

    Six novel cis/trans-but-2-enedioic acid esters had been synthesized to discover the new bioactive molecules that could kill food-related bacteria and fungi. Their structures were analyzed by melting point, LC-MS, 1H NMR and 13C NMR. 4-(Methoxycarbonyl) phenyl ethyl fumarate (6b) was also characterized by single-crystal X-ray diffraction. Their antimicrobial activities were evaluated in vitro by measuring the minimal inhibitory concentration (MIC). Compared with the single monomethyl fumarate and methyl 4-hydroxybenzoate, these compounds had stronger antimicrobial activity against all the eight microorganisms. Among the antibacterial and antifungal compounds, 4-(methoxycarbonyl) phenyl methyl fumarate (6a) showed the best antimicrobial activity. The electronic properties of these compounds were calculated by the density functional theory (DFT) method with 6-31G (d, p) basis set. DFT studies indicated that molecular electrostatic potential (MEP) map, ELUMO, energy gap, electronegativity and electrophilicity index could be helpful to understand the various antimicrobial activities among these compounds. The antimicrobial activity of compound 6a was evaluated in vitro against Salmonellacholeraesuis subsp. choleraesuis, Lactococcus lactis subsp. lactis and Saccharomyces cerevisiae by time-kill, and it was found that compound 6a exhibited significant microbiocidal activity against the three microorganisms.

  4. Process Optimization for Ethyl Ester Production in Fixed Bed Reactor Using Calcium Oxide Impregnated Palm Shell Activated Carbon (CaO/PSAC

    Directory of Open Access Journals (Sweden)

    A Buasri

    2012-11-01

    Full Text Available : The continuous production of ethyl ester was studied by using a steady-state fixed bed reactor (FBR. Transesterification of palm stearin (PS and waste cooking palm oil (WCPO with ethanol in the presence of calcium oxide impregnated palm shell activated carbon (CaO/PSAC solid catalyst was investigated. This work was determined the optimum conditions for the production of ethyl ester from PS and WCPO in order to obtain fatty acid ethyl ester (FAEE with the highest yield. The effects of reaction variables such as residence time, ethanol/oil molar ratio, reaction temperature, catalyst bed height and reusability of catalyst in a reactor system on the yield of biodiesel were considered. The optimum conditions were the residence time 2-3 h, ethanol/oil molar ratio 16-20, reaction temperature at 800C, and catalyst bed height 300 mm which yielded 89.46% and 83.32% of the PS and WCPO conversion, respectively. CaO/PSAC could be used repeatedly for 4 times without any activation treatment and no obvious activity loss was observed. It has potential for industrial application in the transesterification of triglyceride (TG. The fuel properties of biodiesel were determined. Keywords: biodiesel, calcium oxide, ethyl ester, fixed bed reactor, palm shell activated carbon

  5. Cu-catalyzed C(sp³)-H bond activation reaction for direct preparation of cycloallyl esters from cycloalkanes and aromatic aldehydes.

    Science.gov (United States)

    Zhao, Jincan; Fang, Hong; Han, Jianlin; Pan, Yi

    2014-05-02

    Cu-catalyzed dehydrogenation-olefination and esterification of C(sp(3))-H bonds of cycloalkanes with TBHP as an oxidant has been developed. The reaction involves four C-H bond activations and gives cycloallyl ester products directly from cycloalkanes and aromatic aldehydes.

  6. Type 2 diabetes mellitus is associated with differential effects on plasma cholesteryl ester transfer protein and phospholipid transfer protein activities and concentrations

    NARCIS (Netherlands)

    Dullaart, RPF; De Vries, R; Scheek, L; Borggreve, SE; Van Gent, T; Dallinga-Thie, GM; Ito, M; Nagano, M; Sluiter, WJ; Hattori, H; Van Tol, A

    Background: Human plasma contains two lipid transfer proteins, cholesteryl ester transfer protein (CETP) and phospholipid transfer protein (PLTP), which are crucial in reverse cholesterol transport. Methods: Plasma CETP and PLTP activity levels and concentrations in 16 type 2 diabetic patients and

  7. Dimethyl ester of bilirubin exhibits anti-inflammatory activity through inhibition of secretory phospholipase A2, lipoxygenase and cyclooxygenase.

    Science.gov (United States)

    Joshi, Vikram; Umashankara, M; Ramakrishnan, Chandrasekaran; Nanjaraj Urs, Ankanahalli N; Suvilesh, Kanve Nagaraj; Velmurugan, Devadasan; Rangappa, Kanchugarakoppal S; Vishwanath, Bannikuppe Sannanaik

    2016-05-15

    Overproduction of arachidonic acid (AA) mediated by secretory phospholipase A2 group IIA (sPLA2IIA) is a hallmark of many inflammatory disorders. AA is subsequently converted into pro-inflammatory eicosanoids through 5-lipoxygenase (5-LOX) and cyclooxygenase-1/2 (COX-1/2) activities. Hence, inhibition of sPLA2IIA, 5-LOX and COX-1/2 activities is critical in regulating inflammation. We have previously reported unconjugated bilirubin (UCB), an endogenous antioxidant, as sPLA2IIA inhibitor. However, lipophilic UCB gets conjugated in liver with glucuronic acid into hydrophilic conjugated bilirubin (CB). Since hydrophobicity is pre-requisite for sPLA2IIA inhibition, conjugation reduces the efficacy of UCB. In this regard, UCB was chemically modified and derivatives were evaluated for sPLA2IIA, 5-LOX and COX-1/2 inhibition. Among the derivatives, BD1 (dimethyl ester of bilirubin) exhibited ∼ 3 fold greater inhibitory potency towards sPLA2IIA compared to UCB. Both UCB and BD1 inhibited human 5-LOX and COX-2 activities; however only BD1 inhibited AA induced platelet aggregation. Molecular docking studies demonstrated BD1 as better inhibitor of aforesaid enzymes than UCB and other endogenous antioxidants. These data suggest that BD1 exhibits strong anti-inflammatory activity through inhibition of AA cascade enzymes which is of great therapeutic importance. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Fibrinolytic Activity and Dose-Dependent Effect of Incubating Human Blood Clots in Caffeic Acid Phenethyl Ester: In Vitro Assays

    Directory of Open Access Journals (Sweden)

    Abuzar Elnager

    2015-01-01

    Full Text Available Background. Caffeic acid phenethyl ester (CAPE has been reported to possess time-dependent fibrinolytic activity by in vitro assay. This study is aimed at investigating fibrinolytic dose-dependent activity of CAPE using in vitro assays. Methods. Standardized human whole blood (WB clots were incubated in either blank controls or different concentrations of CAPE (3.75, 7.50, 15.00, 22.50, and 30.00 mM. After 3 hours, D-dimer (DD levels and WB clot weights were measured for each concentration. Thromboelastography (TEG parameters were recorded following CAPE incubation, and fibrin morphology was examined under a confocal microscope. Results. Overall, mean DD (μg/mL levels were significantly different across samples incubated with different CAPE concentrations, and the median pre- and postincubation WB clot weights (grams were significantly decreased for each CAPE concentration. Fibrin removal was observed microscopically and indicated dose-dependent effects. Based on the TEG test, the Ly30 fibrinolytic parameter was significantly different between samples incubated with two different CAPE concentrations (15.0 and 22.50 mM. The 50% effective dose (ED50 of CAPE (based on DD was 1.99 mg/mL. Conclusions. This study suggests that CAPE possesses fibrinolytic activity following in vitro incubation and that it has dose-dependent activities. Therefore, further investigation into CAPE as a potential alternative thrombolytic agent should be conducted.

  9. Antibacterial Activity of Protocatechuic Acid Ethyl Ester on Staphylococcus aureus Clinical Strains Alone and in Combination with Antistaphylococcal Drugs

    Directory of Open Access Journals (Sweden)

    Maria Miklasińska

    2015-07-01

    Full Text Available The aim of the presented study was to examine in vitro the antibacterial activity of protocatechuic acid ethyl ester (ethyl 3,4-dihydroxybenzoate, EDHB against Staphylococcus aureus clinical isolates alone and in the combination with four selected antibiotics. The EDHB antimicrobial activity was tested against twenty S. aureus strains isolated from the clinical samples, and three reference strains. The phenotypes and genotypes of resistance to methicillin for the tested strains were defined as well as the phenotypic resistance to macrolides, lincosamides and streptogramin B (MLSB. EDHB displayed diverse activity against examined S. aureus strains with the minimal inhibitory concentration (MIC within the range from 64 to 1024 µg/mL. Addition of ¼ MIC of EDHB into the Mueller-Hinton Agar (MHA resulted in augmented antibacterial effect in the presence of clindamycin. In the case of cefoxitin no synergistic effect with EDHB was noted. For erythromycin and vancomycin the decrease of mean MICs in the presence of EDHB was observed but did not reach statistical significance. The results of the present study showed that in vitro EDHB possesses antibacterial activity against S. aureus clinical strains and triggers a synergistic antimicrobial effect with clindamycin and to the lesser extent with erythromycin and vancomycin.

  10. Novel Antidepressant-Like Activity of Caffeic Acid Phenethyl Ester Is Mediated by Enhanced Glucocorticoid Receptor Function in the Hippocampus

    Directory of Open Access Journals (Sweden)

    Mi-Sook Lee

    2014-01-01

    Full Text Available Caffeic acid phenethyl ester (CAPE is an active component of propolis that has a variety of potential pharmacological effects. Although we previously demonstrated that propolis has antidepressant-like activity, the effect of CAPE on this activity remains unknown. The present study assessed whether treatment with CAPE (5, 10, and 20 µmol/kg for 21 days has an antidepressant-like effect in mice subjected to chronic unpredictable stress via tail suspension (TST and forced swim (FST tests. CAPE administration induced behaviors consistent with an antidepressant effect, evidenced by decreased immobility in the TST and FST independent of any effect on serum corticosterone secretion. Western blots, conducted subsequent to behavioral assessment, revealed that CAPE significantly decreased glucocorticoid receptor phosphorylation at S234 (pGR(S234, resulting in an increased pGR(S220/S234 ratio. We also observed negative correlations between pGR(S220/(S234 and p38 mitogen-activated protein kinase (p38MAPK phosphorylation, which was decreased by CAPE treatment. These findings suggest that CAPE treatment exerts an antidepressant-like effect via downregulation of p38MAPK phosphorylation, thereby contributing to enhanced GR function.

  11. Active and Passive Physician-Assisted Dying and the Terminal Disease Requirement.

    Science.gov (United States)

    Varelius, Jukka

    2016-11-01

    The view that voluntary active euthanasia and physician-assisted suicide should be made available for terminal patients only is typically warranted by reference to the risks that the procedures are seen to involve. Though they would appear to involve similar risks, the commonly endorsed end-of-life practices referred to as passive euthanasia are available also for non-terminal patients. In this article, I assess whether there is good reason to believe that the risks in question would be bigger in the case of voluntary active euthanasia and physician-assisted suicide than in that of passive euthanasia. I propose that there is not. On that basis, I suggest that limiting access to voluntary active euthanasia and physician-assisted suicide to terminal patients only is not consistent with accepting the existing practices of passive euthanasia. © 2016 John Wiley & Sons Ltd.

  12. Phospho-dependent Accumulation of GABABRs at Presynaptic Terminals after NMDAR Activation.

    Science.gov (United States)

    Hannan, Saad; Gerrow, Kim; Triller, Antoine; Smart, Trevor G

    2016-08-16

    Here, we uncover a mechanism for regulating the number of active presynaptic GABAB receptors (GABABRs) at nerve terminals, an important determinant of neurotransmitter release. We find that GABABRs gain access to axon terminals by lateral diffusion in the membrane. Their relative accumulation is dependent upon agonist activation and the presence of the two distinct sushi domains that are found only in alternatively spliced GABABR1a subunits. Following brief activation of NMDA receptors (NMDARs) using glutamate, GABABR diffusion is reduced, causing accumulation at presynaptic terminals in a Ca(2+)-dependent manner that involves phosphorylation of GABABR2 subunits at Ser783. This signaling cascade indicates how synaptically released glutamate can initiate, via a feedback mechanism, increased levels of presynaptic GABABRs that limit further glutamate release and excitotoxicity. Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.

  13. N-terminal truncation of the dopamine transporter abolishes phorbol ester- and substance P receptor-stimulated phosphorylation without impairing transporter internalization

    DEFF Research Database (Denmark)

    Granas, Charlotta; Ferrer, Jasmine; Loland, Claus Juul

    2003-01-01

    (q)-coupled human substance P receptor (hNK-1) co-expressed with hDAT in HEK293 cells and in N2A neuroblastoma cells. In both cell lines, activation of the hNK-1 receptor by substance P reduced the V(max) for [(3)H]dopamine uptake to the same degree as did PMA ( approximately 50 and approximately 20% in HEK293...

  14. Enhancement of lipase catalyzed-fatty acid methyl esters production from waste activated bleaching earth by nullification of lipase inhibitors.

    Science.gov (United States)

    Dwiarti, Lies; Ali, Ehsan; Park, Enoch Y

    2010-01-01

    This study sought to identify inhibitory factors of lipase catalyzed-fatty acid methyl esters (FAME) production from waste activated bleaching earth (wABE). During the vegetable oil refinery process, activated bleaching earth (ABE) is used for removing the impure compounds, but adsorbs vegetable oil up to 35-40% as on a weight basis, and then the wABE is discarded as waste material. The impurities were extracted from the wABE with methanol and evaluated by infra-red (IR) spectroscopy, which revealed that some were chlorophyll-plant pigments. The chlorophylls inhibited the lipase during FAME conversion from wABE. The inhibition by a mixture of chlorophyll a and b was found to be competitive. The inhibition of the enzymatic hydrolysis of waste vegetable oil contained in wABE by chlorophyll a alone was competitive, while the inhibition by chlorophyll b alone was non-competitive. Furthermore, the addition of a small amount of alkali nullified this inhibitory effect and accelerated the FAME production rate. When 0.9% KOH (w/w wABE) was added to the transesterification reaction with only 0.05% lipase (w/w wABE), the maximum FAME production rate improved 120-fold, as compared to that without the addition of KOH. The alkali-combined lipase significantly enhanced the FAME production rate from wABE, in spite of the presence of the plant pigments, and even when a lower amount of lipase was used as a catalyst.

  15. Fatty acid methyl ester (FAME) technology for monitoring biological foaming in activated sludge: full scale plant verification.

    Science.gov (United States)

    Lee, J W; Cha, D K; Kim, I; Son, A; Ahn, K H

    2008-02-01

    Fatty acid methyl ester (FAME) technology was evaluated as a monitoring tool for quantification of Gordonia amarae in activated sludge systems. The fatty acid, 19:1 alcohol, which was identified as a unique fatty acid in G. amarae was not only confirmed to be present in foaming plant samples, but the quantity of the signature peak correlated closely with the degree of foaming. Foaming potential experiment provided a range of critical foaming levels that corresponded to G. amarae population. This range of critical Gordonia levels was correlated to the threshold signature FAME amount. Six full-scale wastewater treatment plants were selected based on a survey to participate in our full-scale study to evaluate the potential application of the FAME technique as the Gordonia monitoring tool. Greater amounts of signature FAME were extracted from the mixed liquor samples obtained from treatment plants experiencing Gordonia foaming problems. The amounts of signature FAME correlated well with the conventional filamentous counting technique. These results demonstrated that the relative abundance of the signature FAMEs can be used to quantitatively monitor the abundance of foam-causing microorganism in activated sludge.

  16. Antioxidant activity of phenolic acids and esters present in red wine on human Low-Density Lipoproteins

    Science.gov (United States)

    Urizzi, P.; Monje, M.-C.; Souchard, J.-P.; Abella, A.; Chalas, J.; Lindenbaum, A.; Vergnes, L.; Labidalle, S.; Nepveu, F.

    1999-01-01

    To evaluate the antioxidant activity of different phenolic acids and their esters, three types of experiments have been used. Electron paramagnetic resonance (EPR) quantitative analysis was carried out using the acetaldehyde/xanthine oxidase system and Fenton's reaction to generate superoxide and hydroxyl radicals, respectively. In a second test, hydroperoxides generated by Cu2+-catalysed oxidation of low density lipoproteins (LDL) were quantified by a modified iodometric method. In a third assay, LDL were oxidized with Esterbauer's method and modified LDL species were quantified by HPLC. The results show that the esterified phenolic derivatives present a better antioxidant activity, on the lipoperoxidation of LDL, than the corresponding phenolic acids. Trois expériences ont été menées afin d'évaluer l'activité antioxydante de différents acides et de leurs esters. Une analyse quantitative par résonance paramagnétique électronique (RPE) a été réalisée en utilisant le système acétaldéhyde/xanthine oxydase et la réaction de Fenton générant, respectivement, les radicaux superoxyde et hydroxyle. Dans un second test, les hydroperoxydes générés par une réaction d'oxydation des lipoprotéines de basse densité (LDL) catalysée par Cu2+ ont été quantifiés par une méthode iodométrique modifiée. Dans une troisième étude, les LDL ont été oxydées par la méthode d'Esterbauer et les espèces oxydées ont été quantifiées par HPLC. Les résultats montrent que les dérivés estérifiés présentent une activité antioxydante contre la lipoperoxydation des LDL bien plus importante que celle des acides phénoliques correspondants.

  17. Activation of human acid sphingomyelinase through modification or deletion of C-terminal cysteine.

    Science.gov (United States)

    Qiu, Huawei; Edmunds, Tim; Baker-Malcolm, Jennifer; Karey, Kenneth P; Estes, Scott; Schwarz, Cordula; Hughes, Heather; Van Patten, Scott M

    2003-08-29

    One form of Niemann-Pick disease is caused by a deficiency in the enzymatic activity of acid sphingomyelinase. During efforts to develop an enzyme replacement therapy based on a recombinant form of human acid sphingomyelinase (rhASM), purified preparations of the recombinant enzyme were found to have substantially increased specific activity if cell harvest media were stored for several weeks at -20 degrees C prior to purification. This increase in activity was found to correlate with the loss of the single free thiol on rhASM, suggesting the involvement of a cysteine residue. It was demonstrated that a variety of chemical modifications of the free cysteine on rhASM all result in substantial activation of the enzyme, and the modified cysteine responsible for this activation was shown to be the C-terminal residue (Cys629). Activation was also achieved by copper-promoted dimerization of rhASM (via cysteine) and by C-terminal truncation using carboxypeptidase Y. The role of the C-terminal cysteine in activation was confirmed by creating mutant forms of rhASM in which this residue was either deleted or replaced by a serine, with both forms having substantially higher specific activity than wild-type rhASM. These results indicate that purified rhASM can be activated in vitro by loss of the free thiol on the C-terminal cysteine via chemical modification, dimerization, or deletion of this amino acid residue. This method of activation is similar to the cysteine switch mechanism described previously for matrix metalloproteinases and could represent a means of posttranslational regulation of ASM activity in vivo.

  18. Saccharomyces kudriavzevii and Saccharomyces uvarum differ from Saccharomyces cerevisiae during the production of aroma-active higher alcohols and acetate esters using their amino acidic precursors.

    Science.gov (United States)

    Stribny, Jiri; Gamero, Amparo; Pérez-Torrado, Roberto; Querol, Amparo

    2015-07-16

    Higher alcohols and acetate esters are important flavour and aroma components in the food industry. In alcoholic beverages these compounds are produced by yeast during fermentation. Although Saccharomyces cerevisiae is one of the most extensively used species, other species of the Saccharomyces genus have become common in fermentation processes. This study analyses and compares the production of higher alcohols and acetate esters from their amino acidic precursors in three Saccharomyces species: Saccharomyces kudriavzevii, Saccharomyces uvarum and S. cerevisiae. The global volatile compound analysis revealed that S. kudriavzevii produced large amounts of higher alcohols, whereas S. uvarum excelled in the production of acetate esters. Particularly from phenylalanine, S. uvarum produced the largest amounts of 2-phenylethyl acetate, while S. kudriavzevii obtained the greatest 2-phenylethanol formation from this precursor. The present data indicate differences in the amino acid metabolism and subsequent production of flavour-active higher alcohols and acetate esters among the closely related Saccharomyces species. This knowledge will prove useful for developing new enhanced processes in fragrance, flavour, and food industries. Copyright © 2015. Published by Elsevier B.V.

  19. The membranotropic activity of N-terminal peptides from the pore ...

    Indian Academy of Sciences (India)

    The membranotropic activity of N-terminal peptides from the pore-forming proteins sticholysin I and II is modulated by hydrophobic and electrostatic interactions ... Center for Protein Studies, Biology Faculty, University of Havana, Havana, Cuba; Department of Applied Physics, Institute of Physics, University of São Paulo, São ...

  20. Esters of Quinoxaline 1ˏ4-Di-N-oxide with Cytotoxic Activity on Tumor Cell Lines Based on NCI-60 Panel

    Science.gov (United States)

    Rivera, Gildardo; Ahmad Shah, Syed Shoaib; Arrieta-Baez, Daniel; Palos, Isidro; Mongue, Antonio; Sánchez-Torres, Luvia Enid

    2017-01-01

    Quinoxalines display diverse and interesting pharmacological activities as antibacterial, antiviral, antiparasitic and anticancer agents. Particularly, their 1ˏ4-di-N-oxide derivatives have proved to be cytotoxic agents that are active under hypoxic conditions as that of solid tumours. A new series of quinoxaline 1ˏ4-di-N-oxide substitutes at 7-position with esters group were synthetized and characterized by infrared (IR), proton nuclear magnetic resonance (1H-NMR), spectroscopy, and elemental analysis. Seventeen derivatives (M1-M3, E1-E8, P1-P3 and DR1-DR3) were selected and evaluated for antitumor activities using the NCI-60 human tumor cell lines screen. Results showed that E7, P3 and E6 were the most active compounds against the cell lines tested. Substitutions at 7-position with esters group not necessarily affect the biological activity, but the nature of the esters group could exert an influence on the selectivity. Additionally, substitutions at 2-position influenced the cytotoxic activity of the compounds. PMID:29201086

  1. Semisynthetic Esters of 17-Hydroxycativic Acid with in Vitro Cytotoxic Activity against Leukemia Cell Lines

    Czech Academy of Sciences Publication Activity Database

    Cavallaro, V.; Řezníčková, Eva; Jorda, Radek; Alza, N.P.; Murray, A.P.; Kryštof, Vladimír

    2017-01-01

    Roč. 40, č. 11 (2017), s. 1923-1928 ISSN 0918-6158 R&D Projects: GA MŠk(CZ) LO1204 Institutional support: RVO:61389030 Keywords : biological evaluation * derivatives * andrographolide * apoptosis * cancer * agents * diterpenes * inhibition * activation * chemistry * diterpenoid * 17-hydroxycativic acid * cytotoxic activity * human cancer cell * apoptosis Subject RIV: EB - Genetics ; Molecular Biology OBOR OECD: Hematology Impact factor: 1.683, year: 2016

  2. Efficient production of fatty acid methyl ester from waste activated bleaching earth using diesel oil as organic solvent.

    Science.gov (United States)

    Kojima, Seiji; Du, Dongning; Sato, Masayasu; Park, Enoch Y

    2004-01-01

    Fatty acid methyl ester (FAME) production from waste activated bleaching earth (ABE) discarded by the crude oil refining industry was investigated using fossil fuel as a solvent in the esterification of triglycerides. Lipase from Candida cylindracea showed the highest stability in diesel oil. Using diesel oil as a solvent, 3 h was sufficient to obtain a yield of approximately 100% of FAME in the presence of 10% lipase from waste ABE. Kerosene was also a good solvent in the esterification of triglycerides embedded in the waste ABE. Fuel analysis showed that the FAME produced using diesel oil as a solvent complied with the Japanese diesel standard and the 10% residual carbon amount was lower than that of FAME produced using other solvents. Use of diesel oil as solvent in the FAME production from the waste ABE simplified the process, because there was no need to separate the organic solvent from the FAME-solvent mixture. These results demonstrate a promising reutilization method for the production of FAME, for use as a biodiesel, from industrial waste resources containing waste vegetable oils.

  3. Conversion of Amides to Esters by the Nickel-Catalyzed Activation of Amide C–N Bonds

    Science.gov (United States)

    Hie, Liana; Fine Nathel, Noah F.; Shah, Tejas K.; Baker, Emma L.; Hong, Xin; Yang, Yun-Fang; Liu, Peng; Houk, K. N.; Garg, Neil K.

    2015-01-01

    Amides are common functional groups that have been well studied for more than a century.1 They serve as the key building blocks of proteins and are present in an broad range of other natural and synthetic compounds. Amides are known to be poor electrophiles, which is typically attributed to resonance stability of the amide bond.1,2 Whereas Nature can easily cleave amides through the action of enzymes, such as proteases,3 the ability to selectively break the C–N bond of an amide using synthetic chemistry is quite difficult. In this manuscript, we demonstrate that amide C–N bonds can be activated and cleaved using nickel catalysts. We have used this methodology to convert amides to esters, which is a challenging and underdeveloped transformation. The reaction methodology proceeds under exceptionally mild reaction conditions, and avoids the use of a large excess of an alcohol nucleophile. Density functional theory (DFT) calculations provide insight into the thermodynamics and catalytic cycle of this unusual transformation. Our results provide a new strategy to harness amide functional groups as synthons and are expected fuel the further use of amides for the construction of carbon–heteroatom or carbon–carbon bonds using non-precious metal catalysis. PMID:26200342

  4. Esters of pyrazinoic acid are active against pyrazinamide-resistant strains of Mycobacterium tuberculosis and other naturally resistant mycobacteria in vitro and ex vivo within macrophages.

    KAUST Repository

    Pires, David; Valente, Emí lia; Simoes, Marta; Carmo, Nuno; Testa, Bernard; Constantino, Luí s; Anes, Elsa

    2015-01-01

    In previous work, we have shown that POA esters and amides synthesized in our laboratory were stable in plasma. Although the amides did not present significant activity, the esters were active against sensitive mycobacteria at concentrations 5-to-10 fold lower than those of PZA. Here, we report that these POA derivatives possess antibacterial efficacy in vitro and ex vivo against several species and strains of Mycobacterium with natural or acquired resistance to PZA, including M. bovis and M. avium. Our results indicate that the resistance was probably overcome by cleavage of the prodrugs into POA and a long-chain alcohol. Although it is not possible to rule out that the esters may have intrinsic activity per se, we bring evidence here that long-chain fatty alcohols possess a significant anti-mycobacterial effect against PZA-resistant species and strains and are not mere inactive promoieties. These findings may lead to candidate dual-drugs having enhanced activity against both PZA-susceptible and PZA-resistant isolates and being suitable for clinical development.

  5. Synthesis and antitumour activity of arctigenin amino acid ester derivatives against H22 hepatocellular carcinoma.

    Science.gov (United States)

    Cai, Enbo; Guo, Shijie; Yang, Limin; Han, Mei; Xia, Jing; Zhao, Yan; Gao, Xiaorui; Wang, Yu

    2018-02-01

    Arctigenin (ARG) is famous in its abundant pharmacological activity. However, many researches in it entered the bottleneck period because of its poor water solubility. The derivatives of ARG have been synthesised with five amino acids which have t-Butyloxy carbonyl (BOC) as a protective group. We examined the effects of removing BOC. The results showed that the amino acid derivatives without protective group have better water solubility and nitrite-clearing ability than ARG. Based on these results, ARG6' and ARG9' were selected at a dosage of 40 mg/kg to evaluate their antitumour activity. The percentage inhibition rate of ARG6' and ARG9' were 55.87 and 51.40, respectively, which was twice as much as ARG. Furthermore, they could increase liver and kidney indexes and produce less damage in these organs. In brief, this study provides a basis for new drug development.

  6. Unsaturated fatty acids lactose esters: cytotoxicity, permeability enhancement and antimicrobial activity.

    Science.gov (United States)

    Lucarini, Simone; Fagioli, Laura; Campana, Raffaella; Cole, Hannah; Duranti, Andrea; Baffone, Wally; Vllasaliu, Driton; Casettari, Luca

    2016-10-01

    Sugar based surfactants conjugated with fatty acid chains are an emerging broad group of highly biocompatible and biodegradable compounds with established and potential future applications in the pharmaceutical, cosmetic and food industries. In this work, we investigated absorption enhancing and antimicrobial properties of disaccharide lactose, monoesterified with unsaturated fatty acids through an enzymatic synthetic approach. After chemical and cytotoxicity characterizations, their permeability enhancing activity was demonstrated using intestinal Caco-2 monolayers through transepithelial electrical resistance (TEER) and permeability studies. The synthesized compounds, namely lactose palmitoleate (URB1076) and lactose nervonate (URB1077), were shown to exhibit antimicrobial activity versus eight pathogenic species belonging to Gram-positive, Gram-negative microorganisms and fungi. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Phorbol ester-induced serine phosphorylation of the insulin receptor decreases its tyrosine kinase activity.

    Science.gov (United States)

    Takayama, S; White, M F; Kahn, C R

    1988-03-05

    The effect of 12-O-tetradecanoylphorbol-13-acetate (TPA) on the function of the insulin receptor was examined in intact hepatoma cells (Fao) and in solubilized extracts purified by wheat germ agglutinin chromatography. Incubation of ortho[32P]phosphate-labeled Fao cells with TPA increased the phosphorylation of the insulin receptor 2-fold after 30 min. Analysis of tryptic phosphopeptides from the beta-subunit of the receptor by reverse-phase high performance liquid chromatography and determination of their phosphoamino acid composition suggested that TPA predominantly stimulated phosphorylation of serine residues in a single tryptic peptide. Incubation of the Fao cells with insulin (100 nM) for 1 min stimulated 4-fold the phosphorylation of the beta-subunit of the insulin receptor. Prior treatment of the cells with TPA inhibited the insulin-stimulated tyrosine phosphorylation by 50%. The receptors extracted with Triton X-100 from TPA-treated Fao cells and purified on immobilized wheat germ agglutinin retained the alteration in kinase activity and exhibited a 50% decrease in insulin-stimulated tyrosine autophosphorylation and phosphotransferase activity toward exogenous substrates. This was due primarily to a decrease in the Vmax for these reactions. TPA treatment also decreased the Km of the insulin receptor for ATP. Incubation of the insulin receptor purified from TPA-treated cells with alkaline phosphatase decreased the phosphate content of the beta-subunit to the control level and reversed the inhibition, suggesting that the serine phosphorylation of the beta-subunit was responsible for the decreased tyrosine kinase activity. Our results support the notion that the insulin receptor is a substrate for protein kinase C in the Fao cell and that the increase in serine phosphorylation of the beta-subunit of the receptor produced by TPA treatment inhibited tyrosine kinase activity in vivo and in vitro. These data suggest that protein kinase C may regulate the function

  8. Solid-phase microextraction of phthalate esters in water sample using different activated carbon-polymer monoliths as adsorbents.

    Science.gov (United States)

    Lirio, Stephen; Fu, Chung-Wei; Lin, Jhih-Yun; Hsu, Meng-Ju; Huang, Hsi-Ya

    2016-07-13

    In this study, the application of different activated carbon-polymer (AC-polymer) monoliths as adsorbents for the solid-phase microextraction (SPME) of phthalate esters (PAEs) in water sample were investigated. The activated carbon (AC) was embedded in organic polymers, poly(butyl methacrylate-co-ethylene dimethacrylate) (poly(BMA-EDMA)) or poly(styrene-co-divinylbenzene) (poly(STY-DVB)), via a 5-min microwave-assisted or a 15-min water bath heating polymerization. Preliminary investigation on the performance of the native poly(BMA-EDMA) and poly(STY-DVB) demonstrated remarkable adsorption efficiencies for PAEs. However, due to the strong hydrophobic, π-π, and hydrogen bonding interactions between the analytes and polymers, low extraction recoveries were achieved. In contrast, the presence of AC in native polymers not only enhanced the adsorption efficiencies but also assisted the PAE desorption, especially for AC-poly(STY-DVB) with extraction recovery ranged of 76.2-99.3%. Under the optimized conditions, the extraction recoveries for intra-, inter-day and column-to-column were in the range of 76.5-100.8% (<3.7% RSDs), 77.2-97.6% (<5.6% RSDs) and 75.5-99.7% (<6.2% RSDs), respectively. The developed AC-poly(STY-DVB) monolithic column showed good mechanical stability, which can be reused for more than 30 extraction times without any significant loss in the extraction recoveries of PAEs. The AC-poly(STY-DVB) monolithic column was successfully applied in SPME of PAEs in water sample with extraction recovery ranged of 78.8%-104.6% (<5.5% RSDs). Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Cholesteryl ester transfer activity in plasma measured by using solid-phase-bound high-density lipoprotein

    International Nuclear Information System (INIS)

    Sparks, D.L.; Frohlich, J.; Cullis, P.; Pritchard, P.H.

    1987-01-01

    We studied the ability of lipid-transfer factors in plasma to promote transfer, to endogenous lipoproteins, of [ 3 H]cholesteryl ester from high-density lipoprotein (HDL) covalently bound to Sepharose 4B beads. After incubation for 2 h at 37 degrees C, 12 to 14% of the [ 3 H]cholesteryl ester had been transferred to the lipoproteins of the plasma, in the proportions 57% to HDL and 43% to low- and very-low-density lipoproteins. This process was a function of the amount of plasma present and was stimulated by addition of partly purified lipid-transfer protein. Transfer also depended on the concentration of donor HDL but was independent of the amount of acceptor lipoprotein. This simple evaluation of cholesteryl ester transfer does not require removal of lipoproteins from the plasma before incubation

  10. Mechanism of phorbol ester-mediated protein kinase C activation in EL4 thymoma cells

    International Nuclear Information System (INIS)

    Huang, F.L.; Arora, P.K.; Hanna, E.E.; Huang, K.P.

    1987-01-01

    Mouse thymoma EL4 cells respond to phorbol 12-myristate 13-acetate (PMA) in interleukin-2 secretion and growth inhibition. A rapid translocation of protein kinase C (PKC) from cytosol to the particulate fraction and followed by proteolytic degradation occur when EL4 cells are incubated with PMA. In the present study the translocated membrane-associated PKC (PP-PKC) was solubilized by buffer containing NP-40 and its behavior on column chromatography, molecular weight, and kinetic properties were compared to the cytosolic PKC (CS-PKC) from untreated cells. From DE-52 cellulose column, CS-PKC could be eluted by buffer containing 0.1 M KCl, whereas PP-PKC was eluted with buffer containing 0.25 M KCl and 0.2% NP-40. On gel filtration the partially purified PP-PKC from DE-52 was separated into two species: a high Mr species, which was a complex of 82KDa PKC, PMA, and lipid as evidenced by immunoblot analysis and labeling with [ 3 H]PMA and [ 3 H]myristic acid, and a 82KDa species, which was free of PMA and lipid. This 82KDa PP-PKC, though similar to the CS-PKC in molecular weight, is distinguishable from the CS-PKC in having lower Ka values for both Ca 2+ and PS and no longer requires diacylglycerol for maximum activation. These results indicate that upon PMA treatment of EL4 cells, the CS-PKC was modified through enhancing the kinase activity and affinity for membrane lipid. The modification results in the translocation and complexing of PKC with membrane lipid and PMA and subsequent degradation

  11. Role of spiral wave pinning in inhomogeneous active media in the termination of atrial fibrillation by electrical cardioversion.

    Science.gov (United States)

    Kuklik, Pawel; Wong, Christopher X; Brooks, Anthony G; Zebrowski, Jan Jacek; Sanders, Prashanthan

    2010-03-01

    Atrial fibrillation is the most common type of arrhythmia to affect humans. One of the treatment modalities for atrial fibrillation is an electrical cardioversion. Electrical cardioversion can result in one of three outcomes: an immediate termination of arrhythmic activity, a delayed termination or unsuccessful termination. The mechanism of delayed termination is unknown. Here we present a model of an atrial fibrillation as a coexistence of several spiral waves pinned to the inhomogeneities in active media. We show that in inhomogeneous system delayed termination can be explained as the unpinning of a spiral wave from inhomogeneities and its termination after collision with the edge of the system. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  12. Inhibition of presynaptic activity by zinc released from mossy fiber terminals during tetanic stimulation.

    Science.gov (United States)

    Minami, Akira; Sakurada, Naomi; Fuke, Sayuri; Kikuchi, Kazuya; Nagano, Tetsuo; Oku, Naoto; Takeda, Atsushi

    2006-01-01

    Zinc exists in high densities in the giant boutons of hippocampal mossy fibers. On the basis of the evidence that zinc decreases extracellular glutamate concentration in the hippocampus, the presynaptic action of zinc released from mossy fibers during high-frequency (tetanic) stimulation was examined using hippocampal slices. The increase in zinc-specific fluorescent signals was observed in both extracellular and intracellular compartments in the mossy fiber terminals during the delivery of tetanic stimuli (100 Hz, 1 sec) to the dentate granule cell layer, suggesting that zinc released from mossy fibers is immediately retaken up by mossy fibers. When mossy fiber terminals were preferentially double-stained with zinc and calcium indicators and tetanic stimuli (100 Hz, 1 sec) were delivered to the dentate granule cell layer, the increase in calcium orange signal during the stimulation was enhanced in mossy fiber terminals by addition of CaEDTA, a membrane-impermeable zinc chelator, and was suppressed by addition of zinc. The decrease in FM4-64 signal (vesicular exocytosis) during tetanic stimulation (10 Hz, 180 sec), which induced mossy fiber long-term potentiation, was also enhanced in mossy fiber terminals by addition of CaEDTA and was suppressed by addition of zinc. The present study demonstrates that zinc released from mossy fibers may be a negative-feedback factor against presynaptic activity during tetanic stimulation.

  13. The antifungal activity of the cuticular and internal fatty acid methyl esters and alcohols in Calliphora vomitoria.

    Science.gov (United States)

    Gołębiowski, Marek; Cerkowniak, Magdalena; Dawgul, Małgorzata; Kamysz, Wojciech; Boguś, Mieczysława I; Stepnowski, Piotr

    2013-07-01

    SUMMARY The composition of the fatty acid methyl ester (FAME) and alcohol fractions of the cuticular and internal lipids of Calliphora vomitoria larvae, pupae and male/female adults was obtained by separating these two fractions by HPLC-LLSD and analysing them quantitatively using GC-MS. Analysis of the cuticular lipids of the worldwide, medically important ectoparasite C. vomitoria revealed 6 FAMEs with odd-numbered carbon chains from C15:0 to C19:0 in the larvae, while internal lipids contained 9 FAMEs ranging from C15:1 to C19:0. Seven FAMEs from C15:0 to C19:0 were identified in the cuticular lipids of the pupae, whereas the internal lipids of the pupae contained 10 FAMEs from C13:0 to C19:0. The cuticular lipids of males and females and also the internal lipids of males contained 5, 7 and 6 FAMEs from C15:0 to C19:0 respectively. Seven FAMEs from C13:0 to C19:0 were identified in the internal lipids of females, and 7, 6, 5 and 3 alcohols were found in the cuticular lipids of larvae, pupae, males and females respectively. Only saturated alcohols with even-numbered carbon chains were present in these lipids. Only 1 alcohol (C22:0) was detected in the internal lipids of C. vomitoria larvae, while just 4 alcohols from - C18:0 to C24:0 - were identified in the internal lipids of pupae, and males and females. We also identified glycerol and cholesterol in the larvae, pupae, males and females of C. vomitoria. The individual alcohols and FAMEs, as well as their mixtures isolated from the cuticular and internal lipids of larvae, pupae, males and females of C. vomitoria, demonstrated antimicrobial activity against entomopathogenic fungi.

  14. Clicked Cinnamic/Caffeic Esters and Amides as Radical Scavengers and 5-Lipoxygenase Inhibitors

    Directory of Open Access Journals (Sweden)

    Jérémie A. Doiron

    2014-01-01

    Full Text Available 5-Lipoxygenase (5-LO is the key enzyme responsible for the conversion of arachidonic acid to leukotrienes, a class of lipid mediators implicated in inflammatory disorders. In this paper, we describe the design, synthesis, and preliminary activity studies of novel clicked caffeic esters and amides as radical scavengers and 5-LO inhibitors. From known 5-LO inhibitor 3 as a lead, cinnamic esters 8a–h and amides 9a–h as well as caffeic esters 15a–h and amides 16a–h were synthesized by Cu(I-catalyzed [1,3]-dipolar cycloaddition with the appropriate azide precursors and terminal alkynes. All caffeic analogs are proved to be good radical scavengers (IC50: 10–20 μM. Esters 15g and 15f possessed excellent 5-LO inhibition activity in HEK293 cells and were equipotent with the known 5-LO inhibitor CAPE and more potent than Zileuton. Several synthesized esters possess activities rivaling Zileuton in stimulated human polymorphonuclear leukocytes.

  15. Preparation of sucrose fatty acid esters as food emulsifiers and evaluation of their surface active and emulsification properties.

    Directory of Open Access Journals (Sweden)

    Megahed, Mohamed G.

    1999-08-01

    Full Text Available A simple method for the preparation of sucrose esters, from fatty acids and the least expensive sucrose, has been conducted. Fatty acids namely lauric, palmitic and oleic were used in their preparation in the absence of any organic solvent. Reasonable yields amounting to 86.5%, 87.3% and 88.6% for sucrose esters of laurate, palmitate and oleate were obtained, respectively. The products were evaluated for their hydrophile-lipophile balance (HLB, surface and interfacial tension properties as well as emulsion stability. The results showed that these sucrose esters exhibit similar properties as those of the commercially prepared compounds.

    Se ha llevado a cabo un método simple para la preparación de ésteres de sacarosa a partir de ácidos grasos y sacarosa de bajo coste. Se han usado ácidos laurico, palmítico y oleico en su preparación, en ausencia de solventes orgánicos. Se obtuvieron rendimientos aceptables del 86.5%, 87.3% y 88.6% para los ásteres del láurico, palmítico y oleico respectivamente. En los productos se evaluaron sus balances hidrófilo-lipófilo (HLB, sus propiedades de tensión superficial e interfacial así como su estabilidad en emulsiones. Los resultados mostraron que estos esteres de sacarosa exhiben propiedades similares a las de los compuestos preparados comercialmente.

  16. Esters of pyrazinoic acid are active against pyrazinamide-resistant strains of Mycobacterium tuberculosis and other naturally resistant mycobacteria in vitro and ex vivo within macrophages.

    KAUST Repository

    Pires, David

    2015-10-05

    Pyrazinamide (PZA) is active against major Mycobacterium tuberculosis species (M. tuberculosis, M. africanum, and M. microti), but not against M. bovis and M. avium. The latter two are mycobacteria species involved in human and cattle tuberculosis and in HIV co-infections, respectively. PZA is a first-line agent for the treatment of human tuberculosis and requires activation by a mycobacterial pyrazinamidase to form the active metabolite pyrazinoic acid (POA). As a result of this mechanism, resistance to PZA as often found in tuberculosis patients is caused by point mutations in pyrazinamidase. In previous work, we have shown that POA esters and amides synthesized in our laboratory were stable in plasma. Although the amides did not present significant activity, the esters were active against sensitive mycobacteria at concentrations 5-to-10 fold lower than those of PZA. Here, we report that these POA derivatives possess antibacterial efficacy in vitro and ex vivo against several species and strains of Mycobacterium with natural or acquired resistance to PZA, including M. bovis and M. avium. Our results indicate that the resistance was probably overcome by cleavage of the prodrugs into POA and a long-chain alcohol. Although it is not possible to rule out that the esters may have intrinsic activity per se, we bring evidence here that long-chain fatty alcohols possess a significant anti-mycobacterial effect against PZA-resistant species and strains and are not mere inactive promoieties. These findings may lead to candidate dual-drugs having enhanced activity against both PZA-susceptible and PZA-resistant isolates and being suitable for clinical development.

  17. Akt kinase C-terminal modifications control activation loop dephosphorylation and enhance insulin response.

    Science.gov (United States)

    Chan, Tung O; Zhang, Jin; Tiegs, Brian C; Blumhof, Brian; Yan, Linda; Keny, Nikhil; Penny, Morgan; Li, Xue; Pascal, John M; Armen, Roger S; Rodeck, Ulrich; Penn, Raymond B

    2015-10-01

    The Akt protein kinase, also known as protein kinase B, plays key roles in insulin receptor signalling and regulates cell growth, survival and metabolism. Recently, we described a mechanism to enhance Akt phosphorylation that restricts access of cellular phosphatases to the Akt activation loop (Thr(308) in Akt1 or protein kinase B isoform alpha) in an ATP-dependent manner. In the present paper, we describe a distinct mechanism to control Thr(308) dephosphorylation and thus Akt deactivation that depends on intramolecular interactions of Akt C-terminal sequences with its kinase domain. Modifications of amino acids surrounding the Akt1 C-terminal mTORC2 (mammalian target of rapamycin complex 2) phosphorylation site (Ser(473)) increased phosphatase resistance of the phosphorylated activation loop (pThr(308)) and amplified Akt phosphorylation. Furthermore, the phosphatase-resistant Akt was refractory to ceramide-dependent dephosphorylation and amplified insulin-dependent Thr(308) phosphorylation in a regulated fashion. Collectively, these results suggest that the Akt C-terminal hydrophobic groove is a target for the development of agents that enhance Akt phosphorylation by insulin. © 2015 Authors; published by Portland Press Limited.

  18. Generation of Active Bovine Terminal Deoxynucleotidyl Transferase (TdT in E.coli

    Directory of Open Access Journals (Sweden)

    Wee Liang Kuan

    2010-08-01

    Full Text Available A synthetic gene encoding bovine terminal deoxynucleotidyl transferase (TdT was generated, cloned into an expression vector and expressed in E.coli. The effects of altering culture and induction conditions on the nature of recombinant protein production were investigated. This led to the expression of active recombinant bovine TdT in E.coli. After purification and characterisation, the activity of the enzyme was assessed in a biological assay for apoptosis. The process described in this report enables the economical production of TdT for high throughput applications.

  19. Generation of Active Bovine Terminal Deoxynucleotidyl Transferase (TdT in E.coli

    Directory of Open Access Journals (Sweden)

    Wee Liang Kuan

    2010-01-01

    Full Text Available A synthetic gene encoding bovine terminal deoxynucleotidyl transferase (TdT was generated, cloned into an expression vector and expressed in E.coli. The effects of altering culture and induction conditions on the nature of recombinant protein production were investigated. This led to the expression of active recombinant bovine TdT in E.coli. After purification and characterisation, the activity of the enzyme was assessed in a biological assay for apoptosis. The process described in this report enables the economical production of TdT for high throughput applications.

  20. Antimicrobial activity of human prion protein is mediated by its N-terminal region.

    Directory of Open Access Journals (Sweden)

    Mukesh Pasupuleti

    Full Text Available BACKGROUND: Cellular prion-related protein (PrP(c is a cell-surface protein that is ubiquitously expressed in the human body. The multifunctionality of PrP(c, and presence of an exposed cationic and heparin-binding N-terminus, a feature characterizing many antimicrobial peptides, made us hypothesize that PrP(c could exert antimicrobial activity. METHODOLOGY AND PRINCIPAL FINDINGS: Intact recombinant PrP exerted antibacterial and antifungal effects at normal and low pH. Studies employing recombinant PrP and N- and C-terminally truncated variants, as well as overlapping peptide 20mers, demonstrated that the antimicrobial activity is mediated by the unstructured N-terminal part of the protein. Synthetic peptides of the N-terminus of PrP killed the Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa, and the Gram-positive Bacillus subtilis and Staphylococcus aureus, as well as the fungus Candida parapsilosis. Fluorescence studies of peptide-treated bacteria, paired with analysis of peptide effects on liposomes, showed that the peptides exerted membrane-breaking effects similar to those seen after treatment with the "classical" human antimicrobial peptide LL-37. In contrast to LL-37, however, no marked helix induction was detected for the PrP-derived peptides in presence of negatively charged (bacteria-mimicking liposomes. PrP furthermore showed an inducible expression during wounding of human skin ex vivo and in vivo, as well as stimulation of keratinocytes with TGF-alpha in vitro. CONCLUSIONS: The demonstration of an antimicrobial activity of PrP, localisation of its activity to the N-terminal and heparin-binding region, combined with results showing an increased expression of PrP during wounding, indicate that PrPs could have a previously undisclosed role in host defense.

  1. Structural and Functional Studies of A. oryzae Cutinase: Enhanced Thermostability and Hydrolytic Activity of Synthetic Ester and Polyester Degradation

    OpenAIRE

    Liu, Zhiqiang; Gosser, Yuying; Baker, Peter James; Ravee, Yaniv; Lu, Ziying; Alemu, Girum; Li, Huiguang; Butterfoss, Glenn L.; Kong, Xiang-Peng; Gross, Richard; Montclare, Jin Kim

    2009-01-01

    Cutinases are responsible for hydrolysis of the protective cutin lipid polyester matrix in plants and thus have been exploited for hydrolysis of small molecule esters and polyesters. Here we explore the reactivity, stability, and structure of Aspergillus oryzae cutinase and compare it to the well-studied enzyme from Fusarium solani. Two critical differences are highlighted in the crystallographic analysis of the A. oryzae structure: (i) an additional disulfide bond and (ii) a topologically fa...

  2. Oral health conditions affect functional and social activities of terminally-ill cancer patients

    Science.gov (United States)

    Fischer, D.J.; Epstein, J.B.; Yao, Y.; Wilkie, D.J.

    2013-01-01

    Purpose Oral conditions are established complications in terminally-ill cancer patients. Yet despite significant morbidity, the characteristics and impact of oral conditions in these patients are poorly documented. The study objective was to characterize oral conditions in terminally-ill cancer patients to determine the presence, severity, and the functional and social impact of these oral conditions. Methods This was an observational clinical study including terminally-ill cancer patients (2.5–3 week life expectancy). Data were obtained via the Oral Problems Scale (OPS) that measures the presence of subjective xerostomia, orofacial pain, taste change, and the functional/social impact of oral conditions and a demographic questionnaire. A standardized oral examination was used to assess objective salivary hypofunction, fungal infection, mucosal erythema, and ulceration. Regression analysis and t test investigated the associations between measures. Results Of 104 participants, most were ≥50 years of age, female, and high-school educated; 45% were African American, 43% Caucasian, and 37% married. Oral conditions frequencies were: salivary hypofunction (98%), mucosal erythema (50%), ulceration (20%), fungal infection (36%), and other oral problems (46%). Xerostomia, taste change, and orofacial pain all had significant functional impact; poral ulcerations had significantly more orofacial pain with a social impact than patients without ulcers (p=.003). Erythema was significantly associated with fungal infection and with mucosal ulceration (pOral conditions significantly affect functional and social activities in terminally-ill cancer patients. Identification and management of oral conditions in these patients should therefore be an important clinical consideration. PMID:24232310

  3. Comparative study of genetic activity of chlorambucil's active metabolite steroidal esters: The role of steroidal skeleton on aneugenic potential

    International Nuclear Information System (INIS)

    Efthimiou, M.; Ouranou, D.; Stephanou, G.; Demopoulos, N.A.; Nikolaropoulos, S.S.; Alevizos, Ph.

    2010-01-01

    p-N,N-bis(2-chloroethyl)aminophenylacetic acid (PHE), a nitrogen mustard analogue and chlorambucil's active metabolite used as chemotherapeutic agent, has been shown that, in addition to its clastogenic activity, induces chromosome delay. In the present study an efford has been made (a) to investigate if the steroidal analogues of PHE (EA-92, EA-97, AK-333, AK-409 and AK-433) exert the same genetic activity as the parent compound, (b) to further analyze the aneugenic activity of nitrogen mustard analogues, (c) to investigate the mechanism by which they exert aneugenic potential and (d) to correlate the genetic activity with chemical structure. For this purpose the Cytokinesis Block Micronucleus (CBMN) assay was conducted in human lymphocytes in vitro and the micronucleus (MN) frequency was determined to investigate their genetic activity. The mechanism of micronucleation was determined in combination with Fluorescence In Situ Hybridization (FISH) using pancentromeric DNA probe. Since one of the mechanisms that chemicals cause aneuploidy is through alterations in the mitotic spindle, we also investigated the effect of the above compounds on the integrity and morphology of the mitotic spindle using double immunofluorescence of β- and γ-tubulin in C 2 C 12 mouse cell line. We found that PHE and its steroidal analogues, EA-92, EA-97, AK-333, AK-409 and AK-433, affect cell proliferation in human lymphocytes and C 2 C 12 mouse cells. All studied compounds are capable of inducing chromosome breakage events, as indicated by the enhanced C - MN frequencies. The less lipophilic compounds are the most genetically active molecules. PHE and only two of the studied analogues, AK-409 and AK-433, the most hydrophilic ones, showed aneugenic potential, by increasing the frequencies of MN containing a whole chromosome. The aneugenic potential of the above referred analogues is associated with amplification of centrosome number, since they caused high multipolar metaphase

  4. Biosynthesis of 2-aminooctanoic acid and its use to terminally modify a lactoferricin B peptide derivative for improved antimicrobial activity.

    Science.gov (United States)

    Almahboub, Sarah A; Narancic, Tanja; Devocelle, Marc; Kenny, Shane T; Palmer-Brown, William; Murphy, Cormac; Nikodinovic-Runic, Jasmina; O'Connor, Kevin E

    2018-01-01

    Terminal modification of peptides is frequently used to improve their hydrophobicity. While N-terminal modification with fatty acids (lipidation) has been reported previously, C-terminal lipidation is limited as it requires the use of linkers. Here we report the use of a biocatalyst for the production of an unnatural fatty amino acid, (S)-2-aminooctanoic acid (2-AOA) with enantiomeric excess > 98% ee and the subsequent use of 2-AOA to modify and improve the activity of an antimicrobial peptide. A transaminase originating from Chromobacterium violaceum was employed with a conversion efficiency 52-80% depending on the ratio of amino group donor to acceptor. 2-AOA is a fatty acid with amino functionality, which allowed direct C- and N-terminal conjugation respectively to an antimicrobial peptide (AMP) derived from lactoferricin B. The antibacterial activity of the modified peptides was improved by up to 16-fold. Furthermore, minimal inhibitory concentrations (MIC) of C-terminally modified peptide were always lower than N-terminally conjugated peptides. The C-terminally modified peptide exhibited MIC values of 25 μg/ml for Escherichia coli, 50 μg/ml for Bacillus subtilis, 100 μg/ml for Salmonella typhimurium, 200 μg/ml for Pseudomonas aeruginosa and 400 μg/ml for Staphylococcus aureus. The C-terminally modified peptide was the only peptide tested that showed complete inhibition of growth of S. aureus.

  5. In vitro antifungal activity of fatty acid methyl esters of the seeds of Annona cornifolia A.St.-Hil. (Annonaceae) against pathogenic fungus Paracoccidioides brasiliensis.

    Science.gov (United States)

    Lima, Luciana Alves Rodrigues dos Santos; Johann, Susana; Cisalpino, Patrícia Silva; Pimenta, Lúcia Pinheiro Santos; Boaventura, Maria Amélia Diamantino

    2011-01-01

    Fatty acids are abundant in vegetable oils. They are known to have antibacterial and antifungal properties. Antifungal susceptibility was evaluated by broth microdilution assay following CLSI (formerly the NCCLS) guidelines against 16 fungal strains of clinical interest. In this work, fatty acid methyl esters (FAME) was able to inhibit 12 clinical strains of the pathogenic fungus Paracoccidioides brasiliensis and were also active in the bioautographic assay against Cladosporium sphaerospermum. FAME was a more potent antifungal than trimethoprim-sulfamethoxazole against P. brasiliensis under the experimental conditions tested.

  6. Novel Insights into Structure-Activity Relationships of N-Terminally Modified PACE4 Inhibitors.

    Science.gov (United States)

    Kwiatkowska, Anna; Couture, Frédéric; Levesque, Christine; Ly, Kévin; Beauchemin, Sophie; Desjardins, Roxane; Neugebauer, Witold; Dory, Yves L; Day, Robert

    2016-02-04

    PACE4 plays important roles in prostate cancer cell proliferation. The inhibition of this enzyme has been shown to slow prostate cancer progression and is emerging as a promising therapeutic strategy. In previous work, we developed a highly potent and selective PACE4 inhibitor, the multi-Leu (ML) peptide, an octapeptide with the sequence Ac-LLLLRVKR-NH2 . Here, with the objective of developing a useful compound for in vivo administration, we investigate the effect of N-terminal modifications. The inhibitory activity, toxicity, stability, and cell penetration properties of the resulting analogues were studied and compared to the unmodified inhibitor. Our results show that the incorporation of a polyethylene glycol (PEG) moiety leads to a loss of antiproliferative activity, whereas the attachment of a lipid chain preserves or improves it. However, the lipidated peptides are significantly more toxic when compared with their unmodified counterparts. Therefore, the best results were achieved not by the N-terminal extension but by the protection of both ends with the d-Leu residue and 4-amidinobenzylamide, which yielded the most stable inhibitor, with an excellent activity and toxicity profile. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Excretion of lead and its biological activity several years after termination of exposure

    Science.gov (United States)

    Přerovská, I.; Teisinger, J.

    1970-01-01

    Přerovská, and Teisinger, J. (1970).Brit. J. industr. Med.,27, 352-355. Excretion of lead and its biological activity several years after termination of exposure. A group of 27 persons who had been treated some years previously for chronic lead poisoning at our clinic, and who had not come into occupational contact with lead since, was examined. Half of them had had no occupational exposure to lead for 3 to 5 years and the others for 8 to 17 years. In most of these persons there is still an increased lead excretion, originating from an increased deposit in the bones. The mobilization test after calcium versenate (CaEDTA) injection was greater than 0·350 mg/24 hours. The values found for haemoglobin, punctate basophilia, coproporphyrin and ALA in urine were normal, but there was, in all cases, a decreased ALA-D activity. This finding suggests biological activity of such negligible lead flow many years after termination of exposure. PMID:5488694

  8. n-Butyrate inhibits Jun NH(2)-terminal kinase activation and cytokine transcription in mast cells

    International Nuclear Information System (INIS)

    Diakos, Christos; Prieschl, Eva E.; Saeemann, Marcus D.; Boehmig, Georg A.; Csonga, Robert; Sobanov, Yury; Baumruker, Thomas; Zlabinger, Gerhard J.

    2006-01-01

    Mast cells are well known to contribute to type I allergic conditions but only recently have been brought in association with chronic relapsing/remitting autoimmune diseases such as celiac disease and ulcerative colitis. Since the bacterial metabolite n-butyrate is considered to counteract intestinal inflammation we investigated the effects of this short chain fatty acid on mast cell activation. Using RNAse protection assays and reporter gene technology we show that n-butyrate downregulates TNF-α transcription. This correlates with an impaired activation of the Jun NH(2)-terminal kinase (JNK) but not other MAP kinases such as ERK and p38 that are largely unaffected by n-butyrate. As a consequence, we observed a decreased nuclear activity of AP-1 and NF-AT transcription factors. These results indicate that n-butyrate inhibits critical inflammatory mediators in mast cells by relatively selectively targeting the JNK signalling

  9. Rab11 is phosphorylated by classical and novel protein kinase C isoenzymes upon sustained phorbol ester activation.

    Science.gov (United States)

    Pavarotti, Martín; Capmany, Anahí; Vitale, Nicolas; Colombo, María Isabel; Damiani, María Teresa

    2012-02-01

    Rab11 is a small GTPase that controls diverse intracellular trafficking pathways. However, the molecular machinery that regulates the participation of Rab11 in those different transport events is poorly understood. In resting cells, Rab11 localizes at the endocytic recycling compartment (ERC), whereas the different protein kinase C (PKC) isoforms display a cytosolic distribution. Sustained phorbol ester stimulation induces the translocation of the classical PKCα and PKCβII isoenzymes to the ERC enriched in Rab11, and results in transferrin recycling inhibition. In contrast, novel PKCε and atypical PKCζ isoenzymes neither redistribute to the perinucleus nor modify transferrin recycling transport after phorbol ester stimulation. Although several Rabs have been shown to be phosphorylated, there is to date no evidence indicating Rab11 as a kinase substrate. In this report, we show that Rab11 appears phosphorylated in vivo in phorbol ester-stimulated cells. A bioinformatic analysis of Rab11 allowed us to identify several high-probability Ser/Thr kinase phosphorylation sites. Our results demonstrate that classical PKC (PKCα and PKCβII but not PKCβI) directly phosphorylate Rab11 in vitro. In addition, novel PKCε and PKCη but not PKCδ isoenzymes also phosphorylate Rab11. Mass spectrometry analysis revealed that Ser 177 is the Rab11 residue to be phosphorylated in vitro by either PKCβII or PKCε. In agreement, the phosphomimetic mutant, Rab11 S177D, retains transferrin at the ERC in the absence of phorbol-12-myristate-13-acetate stimulus. This report shows for the first time that Rab11 is differentially phosphorylated by distinct PKC isoenzymes and that this post-translational modification might be a regulatory mechanism of intracellular trafficking. Copyright © 2012 Soçiété Francaise des Microscopies and Société de Biologie Cellulaire de France.

  10. Phorbol-ester-induced activation of the NF-κB transcription factor involves dissociation of an apparently cytoplasmic NF-κB/inhibitor complex

    International Nuclear Information System (INIS)

    Baeuerle, P.A.; Lenardo, M.; Pierce, J.W.; Baltimore, D.

    1988-01-01

    There is increasing evidence that inducible transcription of genes is mediated through the induction of the activity of trans-acting protein factors. The NF-κB transcription factor provides a model system to study the posttranslational activation of a phorbol-ester-inducible transcription factor. The finding that NF-κB activity is undectable in subcellular fractions from unstimulated cells suggests that NF-κB exists as an inactive precursor. The authors showed that NF-κB is detectable in two different forms. After selective removal of endogenous NF-κB, they demonstrate the existence of a protein inhibitor in cytosolic fractions of unstimulated cells that is able in vitro to convert NF-κB into an inactive desoxycholate-dependent form. The data are consistent with a molecular mechanism of inducible gene expression by which an apparently cytoplasmic transcription factor-inhibitor complex is dissociated by the action of TPA-activated protein kinase C

  11. Synthesis and Antiradical/Antioxidant Activities of Caffeic Acid Phenethyl Ester and Its Related Propionic, Acetic, and Benzoic Acid Analoguesc

    Directory of Open Access Journals (Sweden)

    Mohamed Touaibia

    2012-12-01

    Full Text Available Caffeic acid phenethyl ester (CAPE is a bioactive component isolated from propolis. A series of CAPE analogues was synthesized and their antiradical/antioxidant effects analyzed. The effect of the presence of the double bond and of the conjugated system on the antioxidant effect is evaluated with the analogues obtained from 3-(3,4-dihydroxyphenyl propanoic acid. Those obtained from 2-(3,4-dihydroxyphenyl acetic acid and 3,4-dihydroxybenzoic acid allow the evaluation of the effect of the presence of two carbons between the carbonyl and aromatic system.

  12. Rationalization of the selectivity between 1,3- and 1,2-migration: a DFT study on gold(i)-catalyzed propargylic ester rearrangement.

    Science.gov (United States)

    Jiang, Jingxing; Liu, Yan; Hou, Cheng; Li, Yinwu; Luan, Zihong; Zhao, Cunyuan; Ke, Zhuofeng

    2016-04-14

    Gold catalyzed rearrangement of propargylic esters can undergo 1,3-acyloxy migration to form allenes, or undergo 1,2-acyloxy migration to access gold-carbenoids. The variation in migration leads to different reactivities and diverse cascade transformations. The effect of terminal substituents is very important for the rearrangement. However, it remains ambiguous how terminal substituents govern the selectivity of the rearrangement. This study presents a theoretical model based on the resonance structure of gold activated propargylic ester complexes to rationalize the rearrangement selectivity. Substrates with a major resonance contributor A prefer 5-exo-dig cyclization (1,2-migration), while those with a major resonance contributor B prefer 6-endo-dig cyclization (1,3-migration). This concise model would be helpful in understanding and tuning the selectivity of the metal catalyzed rearrangement of propargylic esters.

  13. Active Center Control of Termination by RNA Polymerase III and tRNA Gene Transcription Levels In Vivo.

    Directory of Open Access Journals (Sweden)

    Keshab Rijal

    2016-08-01

    Full Text Available The ability of RNA polymerase (RNAP III to efficiently recycle from termination to reinitiation is critical for abundant tRNA production during cellular proliferation, development and cancer. Yet understanding of the unique termination mechanisms used by RNAP III is incomplete, as is its link to high transcription output. We used two tRNA-mediated suppression systems to screen for Rpc1 mutants with gain- and loss- of termination phenotypes in S. pombe. 122 point mutation mutants were mapped to a recently solved 3.9 Å structure of yeast RNAP III elongation complex (EC; they cluster in the active center bridge helix and trigger loop, as well as the pore and funnel, the latter of which indicate involvement of the RNA cleavage domain of the C11 subunit in termination. Purified RNAP III from a readthrough (RT mutant exhibits increased elongation rate. The data strongly support a kinetic coupling model in which elongation rate is inversely related to termination efficiency. The mutants exhibit good correlations of terminator RT in vitro and in vivo, and surprisingly, amounts of transcription in vivo. Because assessing in vivo transcription can be confounded by various parameters, we used a tRNA reporter with a processing defect and a strong terminator. By ruling out differences in RNA decay rates, the data indicate that mutants with the RT phenotype synthesize more RNA than wild type cells, and than can be accounted for by their increased elongation rate. Finally, increased activity by the mutants appears unrelated to the RNAP III repressor, Maf1. The results show that the mobile elements of the RNAP III active center, including C11, are key determinants of termination, and that some of the mutations activate RNAP III for overall transcription. Similar mutations in spontaneous cancer suggest this as an unforeseen mechanism of RNAP III activation in disease.

  14. Human immunodeficiency virus long terminal repeat responds to T-cell activation signals

    International Nuclear Information System (INIS)

    Tong-Starksen, S.E.; Luciw, P.A.; Peterlin, B.M.

    1987-01-01

    Human immunodeficiency virus (HIV), the causative agent of AIDS, infects and kills lymphoid cells bearing the CD4 antigen. In an infected cell, a number of cellular as well as HIV-encoded gene products determine the levels of viral gene expression and HIV replication. Efficient HIV replication occurs in activated T cells. Utilizing transient expression assays, the authors show that gene expression directed by the HIV long terminal repeat (LTR) increases in response to T-cell activation signals. The effects of T-cell activation and of the HIV-encoded trans-activator (TAT) are multiplicative. Analysis of mutations and deletions in the HIV LTR reveals that the region responding to T-cell activation signals is located at positions -105 to -80. These sequences are composed of two direct repeats, which are homologous to the core transcriptional enhancer elements in the simian virus 40 genome. The studies reveal that these elements function as the HIV enhancer. By acting directly on the HIV LTR, T-cell activation may play an important role in HIV gene expression and in the activation of latent HIV

  15. Terminal deoxynucleotidyl transferase activity in the regenerating thymus of X-irradiated mice

    International Nuclear Information System (INIS)

    Daculsi, R.; Astier, T.; Legrand, E.; Duplan, J.F.

    1982-01-01

    The distribution of terminal deoyxnucleotidyl transferase (TdT) enzyme activity (EU per 10 8 cells) between peaks I and II was followed for a period of 42 days in regenerating thymus of lethally irradiated (9 Gy) C3H mice restored with 10 6 (C3H x AKR) F1 bone marrow cells. The detection of Thy-1.1 and Thy-1.2 surface antigens allowed for the discrimination between host and donor cells, and the main subpopulations of thymic cells were characterized by their sensitivity to H-2sup(k) antiserum and to dexamethazone. Two peaks of TdT activity could be detected on phosphocellulose chromatographic separation. The distribution of TdT activity between these two peaks was followed during the two periods of thymic endo- and exoregeneration. Peak I TdT activity was closely correlated with the variation in the percentage of the high H-2 population. Peak II activity was mostly related to low H-2 cells. The per cell content of both peak I and peak II activities exceeded the norm in rapidly expanding populations. Finally between days 10 and 14 the TdT activity of the endoregenerating population was apparently not different from that of the exoregenerating population between days 14 and 22. (Auth.)

  16. TRPA1 activation by lidocaine in nerve terminals results in glutamate release increase

    International Nuclear Information System (INIS)

    Piao, L.-H.; Fujita, Tsugumi; Jiang, C.-Y.; Liu Tao; Yue, H.-Y.; Nakatsuka, Terumasa; Kumamoto, Eiichi

    2009-01-01

    We examined the effects of local anesthetics lidocaine and procaine on glutamatergic spontaneous excitatory transmission in substantia gelatinosa (SG) neurons in adult rat spinal cord slices with whole-cell patch-clamp techniques. Bath-applied lidocaine (1-5 mM) dose-dependently and reversibly increased the frequency but not the amplitude of spontaneous excitatory postsynaptic current (sEPSC) in SG neurons. Lidocaine activity was unaffected by the Na + -channel blocker, tetrodotoxin, and the TRPV1 antagonist, capsazepine, but was inhibited by the TRP antagonist, ruthenium red. In the same neuron, the TRPA1 agonist, allyl isothiocyanate, and lidocaine both increased sEPSC frequency. In contrast, procaine did not produce presynaptic enhancement. These results indicate that lidocaine activates TRPA1 in nerve terminals presynaptic to SG neurons to increase the spontaneous release of L-glutamate.

  17. A non-catalytic N-terminal domain negatively influences the nucleotide exchange activity of translation elongation factor 1Bα.

    Science.gov (United States)

    Trosiuk, Tetiana V; Shalak, Vyacheslav F; Szczepanowski, Roman H; Negrutskii, Boris S; El'skaya, Anna V

    2016-02-01

    Eukaryotic translation elongation factor 1Bα (eEF1Bα) is a functional homolog of the bacterial factor EF-Ts, and is a component of the macromolecular eEF1B complex. eEF1Bα functions as a catalyst of guanine nucleotide exchange on translation elongation factor 1A (eEF1A). The C-terminal domain of eEF1Bα is necessary and sufficient for its catalytic activity, whereas the N-terminal domain interacts with eukaryotic translation elongation factor 1Bγ (eEF1Bγ) to form a tight complex. However, eEF1Bγ has been shown to enhance the catalytic activity of eEF1Bα attributed to the C-terminal domain of eEF1Bα. This suggests that the N-terminal domain of eEF1Bα may in some way influence the guanine nucleotide exchange process. We have shown that full-length recombinant eEF1Bα and its truncated forms are non-globular proteins with elongated shapes. Truncation of the N-terminal domain of eEF1Bα, which is dispensable for catalytic activity, resulted in acceleration of the rate of guanine nucleotide exchange on eEF1A compared to full-length eEF1Bα. A similar effect on the catalytic activity of eEF1Bα was observed after its interaction with eEF1Bγ. We suggest that the non-catalytic N-terminal domain of eEF1Bα may interfere with eEF1A binding to the C-terminal catalytic domain, resulting in a decrease in the overall rate of the guanine nucleotide exchange reaction. Formation of a tight complex between the eEF1Bγ and eEF1Bα N-terminal domains abolishes this inhibitory effect. © 2015 FEBS.

  18. The N-terminal, polybasic region is critical for prion protein neuroprotective activity.

    Directory of Open Access Journals (Sweden)

    Jessie A Turnbaugh

    Full Text Available Several lines of evidence suggest that the normal form of the prion protein, PrP(C, exerts a neuroprotective activity against cellular stress or toxicity. One of the clearest examples of such activity is the ability of wild-type PrP(C to suppress the spontaneous neurodegenerative phenotype of transgenic mice expressing a deleted form of PrP (Δ32-134, called F35. To define domains of PrP involved in its neuroprotective activity, we have analyzed the ability of several deletion mutants of PrP (Δ23-31, Δ23-111, and Δ23-134 to rescue the phenotype of Tg(F35 mice. Surprisingly, all of these mutants displayed greatly diminished rescue activity, although Δ23-31 PrP partially suppressed neuronal loss when expressed at very high levels. Our results pinpoint the N-terminal, polybasic domain as a critical determinant of PrP(C neuroprotective activity, and suggest that identification of molecules interacting with this region will provide important clues regarding the normal function of the protein. Small molecule ligands targeting this region may also represent useful therapeutic agents for treatment of prion diseases.

  19. Autocatalytic activity and substrate specificity of the pestivirus N-terminal protease Npro

    International Nuclear Information System (INIS)

    Gottipati, Keerthi; Acholi, Sudheer; Ruggli, Nicolas; Choi, Kyung H.

    2014-01-01

    Pestivirus N pro is the first protein translated in the viral polypeptide, and cleaves itself off co-translationally generating the N-terminus of the core protein. Once released, N pro blocks the host's interferon response by inducing degradation of interferon regulatory factor-3. N pro' s intracellular autocatalytic activity and lack of trans-activity have hampered in vitro cleavage studies to establish its substrate specificity and the roles of individual residues. We constructed N pro -GFP fusion proteins that carry the authentic cleavage site and determined the autoproteolytic activities of N pro proteins containing substitutions at the predicted catalytic sites Glu22 and Cys69, at Arg100 that forms a salt bridge with Glu22, and at the cleavage site Cys168. Contrary to previous reports, we show that N pro' s catalytic activity does not involve Glu22, which may instead be involved in protein stability. Furthermore, N pro does not have specificity for Cys168 at the cleavage site even though this residue is conserved throughout the pestivirus genus. - Highlights: • N pro' s autoproteolysis is studied using N pro -GFP fusion proteins. • N-terminal 17 amino acids are dispensable without loss of protease activity. • The putative catalytic residue Glu22 is not involved in protease catalysis. • No specificity for Cys168 at the cleavage site despite evolutionary conservation. • N pro prefers small amino acids with non-branched beta carbons at the P1 position

  20. Rhodotorulaglutinis phenylalanine/tyrosine ammonia lyase enzyme catalyzed synthesis of the methyl ester of para-hydroxycinnamic acid and its potential antibacterial activity

    Directory of Open Access Journals (Sweden)

    Marybeth C MacDonald

    2016-03-01

    Full Text Available Biotransformation of L-tyrosine methyl ester (L-TM to the methyl ester of para- hydroxycinnamic acid (p-HCAM using Rhodotorula glutinis yeast phenylalanine/tyrosine ammonia lyase (PTAL; EC 4.3.1.26 enzyme was successfully demonstrated for the first time; progress of the reaction was followed by spectrophotometric determination at 315 nm. The following conditions were optimized for maximal formation of p-HCAM: pH (8.5, temperature (37 C, speed of agitation (50 rpm, enzyme concentration (0.080 µM, and substrate concentration (0.50 mM. Under these conditions, the yield of the reaction was ~15% in 1 h incubation period and ~63% after an overnight (~18 h incubation period. The product (p-HCAM of the reaction of PTAL with L-TM was confirmed using Nuclear Magnetic Resonance spectroscopy (NMR. Fourier Transform Infra-Red spectroscopy (FTIR was carried out to rule out potential hydrolysis of p-HCAM during overnight incubation. Potential antibacterial activity of p-HCAM was tested against several strains of Gram positive and Gram negative bacteria. This study describes a synthetically useful transformation, and could have future clinical and industrial applications.

  1. Enhanced osteogenic activity of poly(ester urea) scaffolds using facile post-3D printing peptide functionalization strategies.

    Science.gov (United States)

    Li, Shan; Xu, Yanyi; Yu, Jiayi; Becker, Matthew L

    2017-10-01

    Additive manufacturing has the potential to revolutionize regenerative medicine, but the harsh thermal or photochemical conditions during the 3D printing process limit the inclusion of drugs, growth factors and other biologics within the resulting scaffolds. Functionalization strategies that enable specific placement of bioactive species on the surface of 3D printed structures following the printing process afford a promising approach to sidestep the harsh conditions and incorporate these valuable bioactive molecules with precise control over concentration. Herein, resorbable polymer scaffolds were prepared from propargyl functionalized L-phenylalanine-based poly(ester urea)s (PEUs). Osteogenic growth peptide (OGP) or bone morphogenic protein-2 (BMP-2) peptides were immobilized on PEU scaffolds through surface available propargyl groups via copper-catalyzed azide alkyne cycloaddition (CuAAC) post 3D printing. The presence of either OGP or BMP-2 significantly enhanced hMSCs osteogenic differentiation compared to unfunctionalized scaffolds. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Effect of 6 dietary fatty acids on the postprandial lipid profile, plasma fatty acids, lipoprotein lipase, and cholesterol ester transfer activities in healthy young men

    DEFF Research Database (Denmark)

    Tholstrup, T.; Sandstrøm, B.; Bysted, Anette

    2001-01-01

    , plasma fatty acids, and preheparin lipoprotein lipase and cholesterol ester transfer protein (CETP) activities. Design: Six test fats high (approximate to 43% by wt) in stearic acid, palmitic acid, palmitic + myristic acid, oleic acid, elaidic acid (trans 18:1), and linoleic acid were produced...... to the test-fat meals were observed for plasma lipoprotein triacylglycerol and cholesterol concentrations, plasma fatty acid concentrations, and lipoprotein lipase and CETP activities (diet x time interaction: 0.001 acids stearic and palmitic acids resulted......Background: There is increasing evidence that postprandial triacylglycerol-rich lipoproteins may be related to atherogenic risk. Objective: The objective was to investigate the effect of individual fatty acid intakes on postprandial plasma lipoprotein triacylglycerol and cholesterol concentrations...

  3. Active protein aggregates induced by terminally attached self-assembling peptide ELK16 in Escherichia coli

    Directory of Open Access Journals (Sweden)

    Zhou Bihong

    2011-02-01

    Full Text Available Abstract Background In recent years, it has been gradually realized that bacterial inclusion bodies (IBs could be biologically active. In particular, several proteins including green fluorescent protein, β-galactosidase, β-lactamase, alkaline phosphatase, D-amino acid oxidase, polyphosphate kinase 3, maltodextrin phosphorylase, and sialic acid aldolase have been successfully produced as active IBs when fused to an appropriate partner such as the foot-and-mouth disease virus capsid protein VP1, or the human β-amyloid peptide Aβ42(F19D. As active IBs may have many attractive advantages in enzyme production and industrial applications, it is of considerable interest to explore them further. Results In this paper, we report that an ionic self-assembling peptide ELK16 (LELELKLK2 was able to effectively induce the formation of cytoplasmic inclusion bodies in Escherichia coli (E. coli when attached to the carboxyl termini of four model proteins including lipase A, amadoriase II, β-xylosidase, and green fluorescent protein. These aggregates had a general appearance similar to the usually reported cytoplasmic inclusion bodies (IBs under transmission electron microscopy or fluorescence confocal microscopy. Except for lipase A-ELK16 fusion, the three other fusion protein aggregates retained comparable specific activities with the native counterparts. Conformational analyses by Fourier transform infrared spectroscopy revealed the existence of newly formed antiparallel beta-sheet structures in these ELK16 peptide-induced inclusion bodies, which is consistent with the reported assembly of the ELK16 peptide. Conclusions This has been the first report where a terminally attached self-assembling β peptide ELK16 can promote the formation of active inclusion bodies or active protein aggregates in E. coli. It has the potential to render E. coli and other recombinant hosts more efficient as microbial cell factories for protein production. Our observation might

  4. Alterations of telomerase activity and terminal restriction fragment in gastric cancer and its premalignant lesions.

    Science.gov (United States)

    Yang, S M; Fang, D C; Luo, Y H; Lu, R; Battle, P D; Liu, W W

    2001-08-01

    In order to explore the role of alterations of telomerase activity and terminal restriction fragment (TRF) length in the development and progression of gastric cancer. Telomerase activity was detected in 176 specimens of gastric mucosa obtained through an operation or endoscopical biopsy by using the telomeric repeat amplification protocol (TRAP) assay. Meanwhile, the mean length of TRF was measured with the use of a Southern blot in part of those samples. Telomerase activity was detected in 14 of 57 (24.6%) chronic atrophy gastritis patients, six of 18 (33.3%) intestinal metaplasia patients, three of eight (37.5%) dysplasia patients and 60 of 65 (92.3%) gastric cancer patients, respectively. Normal gastric mucosa revealed no telomerase activity. No association was found between telomerase activity and any clinicopathological parameters. The mean TRF length was decreased gradually with age in normal mucosa and in gastric cancer tissue. Regression analysis demonstrated that the reduction rate in these tissues was 41 +/- 12 base pairs/year. Among 35 gastric cancers, TRF length was shown to be shorter in 20 cases (57.1%), similar in 12 cases (34.3%) and elongated in three cases (7.6%), compared to the corresponding adjacent tissues. The mean TRF length tended to decrease as the mucosa underwent chronic atrophy gastritis, intestinal metaplasia, dysplasia and into gastric cancer. The mean TRF length in gastric cancer was not statistically correlated with clinicopathological parameters and telomerase activity. Our results suggest that telomerase is expressed during the early stage of gastric carcinogenesis, and that the clinical significance of TRF length appears to be limited in gastric cancer.

  5. N-terminal region of gelsolin induces apoptosis of activated hepatic stellate cells by a caspase-dependent mechanism.

    Directory of Open Access Journals (Sweden)

    Budhaditya Mazumdar

    Full Text Available Activated hepatic stellate cells (HSCs are the major source for alteration of extracellular matrix in fibrosis and cirrhosis. Conditioned medium (CM collected from immortalized human hepatocytes (IHH have earlier been shown to be responsible for apoptosis of HSCs. In this study, we have shown that antibodies raised against a peptide derived from a linear B-cell epitope in the N-terminal region of gelsolin identified a gelsolin fragment in IHH CM. Analysis of activated stellate cell death by CM collected from Huh7 cells transfected with plasmids encoding gelsolin deletion mutants suggested that the N-terminal half of gelsolin contained sequences which were responsible for stellate cell death. Further analysis determined that this activity was restricted to a region encompassing amino acids 1-70 in the gelsolin sequence; antibody directed to an epitope within this region was able to neutralize stellate cell death. Gelsolin modulation of cell death using this fragment involved upregulation of TRAIL-R1 and TRAIL-R2, and involved caspase 3 activation by extrinsic pathway. The apoptotic activity of N-terminal gelsolin fragments was restricted to activated but not quiescent stellate cells indicating its potential application in therapeutic use as an anti-fibrotic agent. Gelsolin fragments encompassing N-terminal regions in polypeptides of different molecular sizes were detected by N-terminal peptide specific antiserum in IHH CM immunoprecipitated with chronically HCV infected patient sera, suggesting the presence of autoantibodies generated against N-terminal gelsolin fragments in patients with chronic liver disease.

  6. Ester Tuiksoo / Ester Tuiksoo ; interv. Piret Tali

    Index Scriptorium Estoniae

    Tuiksoo, Ester, 1965-

    2007-01-01

    Juhan Partsi valitsuse (05.04.2004-13.04.2005) ja Andrus Ansipi valitsuse (13.04.2005-) põllumajandusminister Ester Tuiksoo oma lapsepõlvest ja elukutsevalikust, poliitilise karjääri algusest ja erakonna valikust, ministritöö kogemustest, naistest poliitikas

  7. N-terminal amphipathic helix as a trigger of hemolytic activity in antimicrobial peptides: a case study in latarcins.

    Science.gov (United States)

    Polyansky, Anton A; Vassilevski, Alexander A; Volynsky, Pavel E; Vorontsova, Olga V; Samsonova, Olga V; Egorova, Natalya S; Krylov, Nicolay A; Feofanov, Alexei V; Arseniev, Alexander S; Grishin, Eugene V; Efremov, Roman G

    2009-07-21

    In silico structural analyses of sets of alpha-helical antimicrobial peptides (AMPs) are performed. Differences between hemolytic and non-hemolytic AMPs are revealed in organization of their N-terminal region. A parameter related to hydrophobicity of the N-terminal part is proposed as a measure of the peptide propensity to exhibit hemolytic and other unwanted cytotoxic activities. Based on the information acquired, a rational approach for selective removal of these properties in AMPs is suggested. A proof of concept is gained through engineering specific mutations that resulted in elimination of the hemolytic activity of AMPs (latarcins) while leaving the beneficial antimicrobial effect intact.

  8. International conference on safe decommissioning for nuclear activities: Assuring the safe termination of practices involving radioactive materials. Contributed papers

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-07-01

    Thousands of operations involving the use of radioactive substances will end during the current century. While there is considerable regulatory experience in the 'front end' of the regulatory system for practices, the experience at the back end is more limited as fewer practices have actually been terminated. When a practice is terminated because the facility has reached the end of its useful life, action has to betaken to ensure the safe shutdown of the facility and allow the removal of regulatory controls. There are many issues involved in the safe termination of practices. These include setting criteria for the release of material and sites from regulatory control; determining the suitability of the various options for decommissioning nuclear facilities, managing the waste and material released from control (recycling, reuse or disposal), and the eventual remediation of the site. Some countries have put in place regulatory infrastructures and have developed programmes to manage the associated decommissioning and remediation activities. Other countries are at the stage of assessing what is involved in terminating such practices. The purpose of this Conference is to foster an information exchange on the safe an orderly termination of practices that involve the use of radioactive substances, including both decommissioning and environmental remediation, and to promote improved coherence internationally on strategies and criteria for the safe termination of practices.

  9. International conference on safe decommissioning for nuclear activities: Assuring the safe termination of practices involving radioactive materials. Contributed papers

    International Nuclear Information System (INIS)

    2002-01-01

    Thousands of operations involving the use of radioactive substances will end during the current century. While there is considerable regulatory experience in the 'front end' of the regulatory system for practices, the experience at the back end is more limited as fewer practices have actually been terminated. When a practice is terminated because the facility has reached the end of its useful life, action has to betaken to ensure the safe shutdown of the facility and allow the removal of regulatory controls. There are many issues involved in the safe termination of practices. These include setting criteria for the release of material and sites from regulatory control; determining the suitability of the various options for decommissioning nuclear facilities, managing the waste and material released from control (recycling, reuse or disposal), and the eventual remediation of the site. Some countries have put in place regulatory infrastructures and have developed programmes to manage the associated decommissioning and remediation activities. Other countries are at the stage of assessing what is involved in terminating such practices. The purpose of this Conference is to foster an information exchange on the safe an orderly termination of practices that involve the use of radioactive substances, including both decommissioning and environmental remediation, and to promote improved coherence internationally on strategies and criteria for the safe termination of practices

  10. Hepatic expression of inflammatory genes and microRNAs in pigs with high “cholesteryl ester transfer protein” (CETP) activity

    DEFF Research Database (Denmark)

    Cirera, Susanna; Tørsleff, Benedicte C Juul; Ritz, Christian

    2016-01-01

    levels (designated as CETP-high and CETP-low, respectively). Furthermore, breed and gender differences were also investigated. We found significant difference (P hepatic expression levels of several mRNAs and microRNAs between the CETP-high and -low groups (C5, IL1RN, IL18, and miR-223-5p......) promoting the redistribution of cholesteryl esters, triglycerides, and phospholipids between plasma proteins. Moreover, obesity and ORD are often linked with chronic low-grade inflammation leading to insulin resistance and endothelial and microvascular dysfunctions. The aim of this study was to detect...... differences in the hepatic expression of genes involved in low-grade inflammation and of obesity- and cholesterol-related microRNAs in two mixed breed populations of pigs (Yorkshire-Göttingen minipig, YM and Duroc-Göttingen minipig, DM) including males and females, with extreme phenotypes for CETP activity...

  11. Internalization, lysosomal degradation and new synthesis of surface membrane CD4 in phorbol ester-activated T-lymphocytes and U-937 cells

    DEFF Research Database (Denmark)

    Petersen, C M; Christensen, E I; Andresen, B S

    1992-01-01

    degradation was low in resting cells. Endocytosis and/or degradation of anti-CD4 mAb was suppressed by H7, and by inhibitors of membrane traffic (Monensin) and lysosome function (methylamine, chloroquine). Immunocytochemistry localized CD4 to the surface of unstimulated T-cells. Upon PMA stimulation...... occasional labeling was seen in endosomes but whole cell CD4 decreased dramatically. However, methylamine-treated PMA blasts showed accumulation of CD4 in lysosomes and accordingly, pulse-chase experiments in biolabeled cell cultures suggested a manifest reduction of CD4 half-life in response to PMA. Despite...... in activated cells was further evidenced by metabolic labeling and Northern blot analysis demonstrating unaltered or slightly increased CD4 protein and mRNA levels resulting from PMA. Our findings demonstrate that phorbol esters downregulate the cellular CD4 pool by endocytosis and subsequent lysosomal...

  12. Autocatalytic activity and substrate specificity of the pestivirus N-terminal protease N{sup pro}

    Energy Technology Data Exchange (ETDEWEB)

    Gottipati, Keerthi; Acholi, Sudheer [Department of Biochemistry and Molecular Biology, Sealy Center for Structural Biology and Molecular Biophysics, The University of Texas Medical Branch, Galveston, TX 77555-0647 (United States); Ruggli, Nicolas [Institute of Virology and Immunology, CH-3147 Mittelhäusern (Switzerland); Choi, Kyung H., E-mail: kychoi@utmb.edu [Department of Biochemistry and Molecular Biology, Sealy Center for Structural Biology and Molecular Biophysics, The University of Texas Medical Branch, Galveston, TX 77555-0647 (United States)

    2014-03-15

    Pestivirus N{sup pro} is the first protein translated in the viral polypeptide, and cleaves itself off co-translationally generating the N-terminus of the core protein. Once released, N{sup pro} blocks the host's interferon response by inducing degradation of interferon regulatory factor-3. N{sup pro'}s intracellular autocatalytic activity and lack of trans-activity have hampered in vitro cleavage studies to establish its substrate specificity and the roles of individual residues. We constructed N{sup pro}-GFP fusion proteins that carry the authentic cleavage site and determined the autoproteolytic activities of N{sup pro} proteins containing substitutions at the predicted catalytic sites Glu22 and Cys69, at Arg100 that forms a salt bridge with Glu22, and at the cleavage site Cys168. Contrary to previous reports, we show that N{sup pro'}s catalytic activity does not involve Glu22, which may instead be involved in protein stability. Furthermore, N{sup pro} does not have specificity for Cys168 at the cleavage site even though this residue is conserved throughout the pestivirus genus. - Highlights: • N{sup pro'}s autoproteolysis is studied using N{sup pro}-GFP fusion proteins. • N-terminal 17 amino acids are dispensable without loss of protease activity. • The putative catalytic residue Glu22 is not involved in protease catalysis. • No specificity for Cys168 at the cleavage site despite evolutionary conservation. • N{sup pro} prefers small amino acids with non-branched beta carbons at the P1 position.

  13. Characterization of three bioenergetically active respiratory terminal oxidases in the cyanobacterium Synechocystis sp. strain PCC 6803.

    Science.gov (United States)

    Pils, D; Schmetterer, G

    2001-09-25

    Synechocystis sp. PCC 6803 contains three respiratory terminal oxidases (RTOs): cytochrome c oxidase (Cox), quinol oxidase (Cyd), and alternate RTO (ARTO). Mutants lacking combinations of the RTOs were used to characterize these key enzymes of respiration. Pentachlorophenol and 2-heptyl-4-hydroxy-quinoline-N-oxide inhibited Cyd completely, but had little effect on electron transport to the other RTOs. KCN inhibited all three RTOs but the in vivo K(I) for Cox and Cyd was quite different (7 vs. 27 microM), as was their affinity for oxygen (K(M) 1.0 vs. 0.35 microM). ARTO has a very low respiratory activity. However, when uptake of 3-O-methylglucose, an active H+ co-transport, was used to monitor energization of the cytoplasmic membrane, ARTO was similarly effective as the other RTOs. As removal of the gene for cytochrome c(553) had the same effects as removal of ARTO genes, we propose that the ARTO might be a second Cox. The possible functions, localization and regulation of the RTOs are discussed.

  14. Carboxy-terminal truncation activates glp-1 protein to specify vulval fates in Caenorhabditis elegans.

    Science.gov (United States)

    Mango, S E; Maine, E M; Kimble, J

    1991-08-29

    The glp-1 and lin-12 genes encode homologous transmembrane proteins that may act as receptors for cell interactions during development. The glp-1 product is required for induction of germ-line proliferation and for embryogenesis. By contrast, lin-12 mediates somatic cell interactions, including those between the precursor cells that form the vulval hypodermis (VPCs). Here we analyse an unusual allele of glp-1, glp-1(q35), which displays a semidominant multivulva phenotype (Muv), as well as the typical recessive, loss-of-function Glp phenotypes (sterility and embryonic lethality). We find that the effects of glp-1(q35) on VPC development mimic those of dominant lin-12 mutations, even in the absence of lin-12 activity. The glp-1(q35) gene bears a nonsense mutation predicted to eliminate the 122 C-terminal amino acids, including a ProGluSerThr (PEST) sequence thought to destabilize proteins. We suggest that the carboxy terminus bears a negative regulatory domain which normally inactivates glp-1 in the VPCs. We propose that inappropriate glp-1(q35) activity can substitute for lin-12 to determine vulval fate, perhaps by driving the VPCs to proliferate.

  15. Synthesis of trans-disubstituted alkenes by cobalt-catalyzed reductive coupling of terminal alkynes with activated alkenes.

    Science.gov (United States)

    Mannathan, Subramaniyan; Cheng, Chien-Hong

    2012-09-10

    A cobalt-catalyzed reductive coupling of terminal alkynes, RC≡CH, with activated alkenes, R'CH=CH(2), in the presence of zinc and water to give functionalized trans-disubstituted alkenes, RCH=CHCH(2)CH(2)R', is described. A variety of aromatic terminal alkynes underwent reductive coupling with activated alkenes including enones, acrylates, acrylonitrile, and vinyl sulfones in the presence of a CoCl(2)/P(OMe)(3)/Zn catalyst system to afford 1,2-trans-disubstituted alkenes with high regio- and stereoselectivity. Similarly, aliphatic terminal alkynes also efficiently participated in the coupling reaction with acrylates, enones, and vinyl sulfone, in the presence of the CoCl(2)/P(OPh)(3)/Zn system providing a mixture of 1,2-trans- and 1,1-disubstituted functionalized terminal alkene products in high yields. The scope of the reaction was also extended by the coupling of 1,3-enynes and acetylene gas with alkenes. Furthermore, a phosphine-free cobalt-catalyzed reductive coupling of terminal alkynes with enones, affording 1,2-trans-disubstituted alkenes as the major products in a high regioisomeric ratio, is demonstrated. In the reactions, less expensive and air-stable cobalt complexes, a mild reducing agent (Zn) and a simple hydrogen source (water) were used. A possible reaction mechanism involving a cobaltacyclopentene as the key intermediate is proposed. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Gamma radiolysis and vinyl esters

    International Nuclear Information System (INIS)

    De Bruyn, H.; Balic, R.; Gilbert, R.G.

    1998-01-01

    The principle behind γ relaxation of free-radical polymerizations is that the source of initiating radicals can be switched off 'instantaneously'. In the absence of initiating radicals the only kinetic events remaining are propagation, transfer and termination. For monomers whose propagation rate coefficients have been determined, relaxation behaviour can be interpreted to determine radical-loss rate coefficients and test models of loss mechanisms. This technique has been employed successfully on styrene and MMA emulsion polymerizations. In the present study, vinyl acetate and vinyl neo-decanoate (a ten-carbon-branched homologue of vinyl acetate) were studied, with the propagation rate coefficients for both monomers being established by pulsed-laser polymerization. Both were found to exhibit rapid γ relaxation rates in emulsion polymerization. This is a surprising result because mechanisms for rapid relaxation in emulsion polymerizations require that chain transfer to monomer (which is rapid for both monomers) is followed by exit from the particle into the aqueous phase with subsequent re-entry into a radical-containing particle leading to bimolecular termination. It is not unreasonable to suppose that this may be possible for vinyl acetate which is fairly water soluble (∼0.3 M). However, vinyl neo-decanoate is virtually insoluble (∼0.00004 M) and hence desorption is extremely unlikely. The most likely explanation for the observed rapid relaxations is that some of the radicals produced by γ radiolysis are slow to initiate vinyl esters and hence act as radical traps. As vinyl esters are known to be particularly unreactive monomers. it is feasible that this experimental artifact affects them to a much greater extent than some of the monomers studied successfully with this technique in the past

  17. Electrical activity in rat tail artery during asynchronous activation of postganglionic nerve terminals by ciguatoxin-1.

    Science.gov (United States)

    Brock, J. A.; McLachlan, E. M.; Jobling, P.; Lewis, R. J.

    1995-01-01

    1. The effects of ciguatoxin-1 (CTX-1) on the membrane potential of smooth muscle cells have been examined in rat proximal tail arteries isolated in vitro. 2. CTX-1 (> or = 10 pM) increased the frequency of spontaneous excitatory junction potentials (s.e.j.ps). At 100-400 pM, there was also a marked and maintained depolarization (19.7 +/- 1.4 mV, n = 14, at 400 pM). 3. In 20-400 pM CTX-1, perivascular stimuli evoked excitatory junction potentials (e.j.ps) which were prolonged in time course relative to control. 4. Although threshold and latency of the e.j.p. were not affected by CTX-1 ( or = 100 pM. 5. The spontaneous activity and the depolarization produced by CTX-1 were reduced in the presence of Ca2+ (0.1 mM)/Mg2+ (25 mM), omega-conotoxin (0.1 microM) or Cd2+ (50-100 microM). 6. All effects of CTX-1 were abolished by tetrodotoxin (0.3 microM). 7. Raised Ca2+ (6 mM) reduced the depolarization and spontaneous activity produced by CTX-1. 8. In 400 pM CTX-1, the membrane repolarized (17 +/- 3.2 mV, n = 4) following the addition of phentolamine (1 microM). S.e.j.ps and e.j.ps were selectively abolished by suramin (1 mM), and the membrane repolarized by 1.3 +/- 1.6 mV (n = 4). 9. We conclude that CTX-1 releases noradrenaline and ATP by initiating asynchronous discharge of postganglionic perivascular axons. In 100-400 pM CTX-1, the smooth muscle was depolarized to levels resembling those recorded in this artery during ongoing vasoconstrictor discharge in vivo. PMID:8564251

  18. Caffeic Acid Phenethyl Ester Inhibits Oral Cancer Cell Metastasis by Regulating Matrix Metalloproteinase-2 and the Mitogen-Activated Protein Kinase Pathway

    Directory of Open Access Journals (Sweden)

    Chih-Yu Peng

    2012-01-01

    Full Text Available Caffeic acid phenethyl ester (CAPE, an active component extracted from honeybee hives, exhibits anti-inflammatory and anticancer activities. However, the molecular mechanism by which CAPE affects oral cancer cell metastasis has yet to be elucidated. In this study, we investigated the potential mechanisms underlying the effects of CAPE on the invasive ability of SCC-9 oral cancer cells. Results showed that CAPE attenuated SCC-9 cell migration and invasion at noncytotoxic concentrations (0 μM to 40 μM. Western blot and gelatin zymography analysis findings further indicated that CAPE downregulated matrix metalloproteinase-2 (MMP-2 protein expression and inhibited its enzymatic activity. CAPE exerted its inhibitory effects on MMP-2 expression and activity by upregulating tissue inhibitor of metalloproteinase-2 (TIMP-2 and potently decreased migration by reducing focal adhesion kinase (FAK phosphorylation and the activation of its downstream signaling molecules p38/MAPK and JNK. These data indicate that CAPE could potentially be used as a chemoagent to prevent oral cancer metastasis.

  19. Tissue redox activity as a hallmark of carcinogenesis: from early to terminal stages of cancer.

    Science.gov (United States)

    Bakalova, Rumiana; Zhelev, Zhivko; Aoki, Ichio; Saga, Tsuneo

    2013-05-01

    The study aimed to clarify the dynamics of tissue redox activity (TRA) in cancer progression and assess the importance of this parameter for therapeutic strategies. The experiments were carried out on brain tissues of neuroblastoma-bearing, glioma-bearing, and healthy mice. TRA was visualized in vivo by nitroxide-enhanced MRI on anesthetized animals or in vitro by electron paramagnetic resonance spectroscopy on isolated tissue specimens. Two biochemical parameters were analyzed in parallel: tissue total antioxidant capacity (TTAC) and plasma levels of matrix metalloproteinases (MMP). In the early stage of cancer, the brain tissues were characterized by a shorter-lived MRI signal than that from healthy brains (indicating a higher reducing activity for the nitroxide radical), which was accompanied by an enhancement of TTAC and MMP9 plasma levels. In the terminal stage of cancer, tissues in both hemispheres were characterized by a longer-lived MRI signal than in healthy brains (indicating a high-oxidative activity) that was accompanied by a decrease in TTAC and an increase in the MMP2/MMP9 plasma levels. Cancer progression also affected the redox potential of tissues distant from the primary tumor locus (liver and lung). Their oxidative status increased in both stages of cancer. The study shows that tissue redox balance is very sensitive to the progression of cancer and can be used as a diagnostic marker of carcinogenesis. The study also suggests that the noncancerous tissues of a cancer-bearing organism are susceptible to oxidative damage and should be considered a therapeutic target. ©2013 AACR.

  20. DMPD: A pervasive role of ubiquitin conjugation in activation and termination ofIkappaB kinase pathways. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 15809659 A pervasive role of ubiquitin conjugation in activation and termination of...csml) Show A pervasive role of ubiquitin conjugation in activation and termination ofIkappaB kinase pathways.... PubmedID 15809659 Title A pervasive role of ubiquitin conjugation in activation and termina

  1. Constitutive β-catenin activation in osteoblasts impairs terminal osteoblast differentiation and bone quality

    Energy Technology Data Exchange (ETDEWEB)

    Bao, Quanwei; Chen, Sixu; Qin, Hao [State Key Laboratory of Trauma, Burn and Combined injury, Department of Trauma Surgery, Daping Hospital, Third Military Medical University, ChongQing 400042 (China); Feng, Jianquan [Department of Biomedical Sciences, Baylor College of Dentistry, Texas A& M Health Science Center, Dallas, TX 75246 (United States); Liu, Huayu; Liu, Daocheng; Li, Ang; Shen, Yue; Zhong, Xiaozheng; Li, Junfeng [State Key Laboratory of Trauma, Burn and Combined injury, Department of Trauma Surgery, Daping Hospital, Third Military Medical University, ChongQing 400042 (China); Zong, Zhaowen, E-mail: zongzhaowen@sina.cn [State Key Laboratory of Trauma, Burn and Combined injury, Department of Trauma Surgery, Daping Hospital, Third Military Medical University, ChongQing 400042 (China)

    2017-01-01

    Accumulating evidence suggests that Wnt/β-catenin signaling plays a central role in controlling bone mass. We previously reported that constitutive activation of β-catenin (CA-β-catenin) in osteoblasts potentially has side effects on the bone growth and bone remodeling process, although it could increase bone mass. The present study aimed to observe the effects of osteoblastic CA-β-catenin on bone quality and to investigate possible mechanisms of these effects. It was found that CA-β-catenin mice exhibited lower mineralization levels and disorganized collagen in long bones as confirmed by von Kossa staining and sirius red staining, respectively. Also, bone strength decreased significantly in CA-β-catenin mice. Then the effect of CA-β-catenin on biological functions of osteoblasts were investigated and it was found that the expression levels of osteocalcin, a marker for the late differentiation of osteoblasts, decreased in CA-β-catenin mice, while the expression levels of osterix and alkaline phosphatase, two markers for the early differentiation of osteoblasts, increased in CA-β-catenin mice. Furthermore, higher proliferation rate were revealed in osteoblasts that were isolated from CA-β-catenin mice. The Real-time PCR and western blot examination found that the expression level of c-myc and cyclin D1, two G1 progression-related molecules, increased in osteoblasts that were isolated from the CA-β-catenin mice, and the expression levels of CDK14 and cyclin Y, two mitotic-related molecules that can accelerate cells entering into S and G2/M phases, increased in osteoblasts that were isolated from the CA-β-catenin mice. In summary, osteoblastic CA-β-catenin kept osteoblasts in high proliferative state and impaired the terminal osteoblast differentiation, and this led to changed bone structure and decreased bone strength. - Highlights: • Wnt/β-catenin signaling plays a central role in controlling bone mass. • CA-β-catenin has side effects on the bone

  2. Complement activation in leprosy: a retrospective study shows elevated circulating terminal complement complex in reactional leprosy.

    Science.gov (United States)

    Bahia El Idrissi, N; Hakobyan, S; Ramaglia, V; Geluk, A; Morgan, B Paul; Das, P Kumar; Baas, F

    2016-06-01

    Mycobacterium leprae infection gives rise to the immunologically and histopathologically classified spectrum of leprosy. At present, several tools for the stratification of patients are based on acquired immunity markers. However, the role of innate immunity, particularly the complement system, is largely unexplored. The present retrospective study was undertaken to explore whether the systemic levels of complement activation components and regulators can stratify leprosy patients, particularly in reference to the reactional state of the disease. Serum samples from two cohorts were analysed. The cohort from Bangladesh included multi-bacillary (MB) patients with (n = 12) or without (n = 46) reaction (R) at intake and endemic controls (n = 20). The cohort from Ethiopia included pauci-bacillary (PB) (n = 7) and MB (n = 23) patients without reaction and MB (n = 15) patients with reaction. The results showed that the activation products terminal complement complex (TCC) (P ≤ 0·01), C4d (P ≤ 0·05) and iC3b (P ≤ 0·05) were specifically elevated in Bangladeshi patients with reaction at intake compared to endemic controls. In addition, levels of the regulator clusterin (P ≤ 0·001 without R; P < 0·05 with R) were also elevated in MB patients, irrespective of a reaction. Similar analysis of the Ethiopian cohort confirmed that, irrespective of a reaction, serum TCC levels were increased significantly in patients with reactions compared to patients without reactions (P ≤ 0·05). Our findings suggests that serum TCC levels may prove to be a valuable tool in diagnosing patients at risk of developing reactions. © 2016 British Society for Immunology.

  3. Cost Analysis by Applying Time-Driven Activity Based Costing Method in Container Terminals

    OpenAIRE

    Yaşar, R. Şebnem

    2017-01-01

    Container transportation, which can also be called as “industrialization of maritime transportation”, gained significant ground in the world trade by offering numerous technical and economic advantages, and accordingly the container terminals have grown up in importance. Increased competition between container terminals puts pressure on the ports to reduce costs and increase operational productivity. To have the right cost information constitutes a prerequisite for cost reduction. Time-Driven...

  4. The nitrite-oxidizing community in activated sludge from a municipal wastewater treatment plant determined by fatty acid methyl ester-stable isotope probing.

    Science.gov (United States)

    Kruse, Myriam; Zumbrägel, Sabine; Bakker, Evert; Spieck, Eva; Eggers, Till; Lipski, André

    2013-10-01

    Metabolically-active autotrophic nitrite oxidizers from activated sludge were labeled with (13)C-bicarbonate under exposure to different temperatures and nitrite concentrations. The labeled samples were characterized by FAME-SIP (fatty acid methyl ester-stable isotope probing). The compound cis-11-palmitoleic acid, which is the major lipid of the most abundant nitrite oxidizer in activated sludge, Candidatus Nitrospira defluvii, showed (13)C-incorporation in all samples exposed to 3 mM nitrite. Subsequently, the lipid cis-7-palmitoleic acid was labeled, and it indicated the activity of a nitrite oxidizer that was different from the known Nitrospira taxa in activated sludge. The highest incorporation of cis-7-palmitoleic acid label was found after incubation with a nitrite concentration of 0.3 mM at 17 and 22°C. While activity of Nitrobacter populations could not be detected by the FAME-SIP approach, an unknown nitrite oxidizer with the major lipid cis-9 isomer of palmitoleic acid exhibited (13)C-incorporation at 28°C with 30 mM nitrite. These results indicated flexibility of nitrite-oxidizing guilds in a complex community responding to different conditions. Labeled lipids so far not described for activated sludge-associated nitrifiers indicated the presence of unknown nitrite oxidizers in this habitat. The FAME-SIP-based information can be used to define appropriate conditions for the enrichment of nitrite-oxidizing guilds from complex samples. Copyright © 2013 Elsevier GmbH. All rights reserved.

  5. Active uptake of substance P carboxy-terminal heptapeptide (5-11) into rat brain and rabbit spinal cord slices

    Energy Technology Data Exchange (ETDEWEB)

    Nakata, Y; Kusaka, Y; Yajima, H; Segawa, T

    1981-12-01

    We previously reported that nerve terminals and glial cells lack an active uptake system capable of terminating transmitter action of substance P (SP). In the present study, we demonstrated the existence of an active uptake system for SP carboxy-terminal heptapeptide, (5-11)SP. When the slices from either rat brain or rabbit spinal cord were incubated with (3H)(5-11)SP, the uptake of (5-11)SP into slices was observed. The uptake system has the properties of an active transport mechanism: it is dependent on temperature and sensitive to hypoosmotic treatment and is inhibited by ouabain and dinitrophenol (DNP). In the brain, (5-11)SP was accumulated by means of a high-affinity and a low-affinity uptake system. The Km and the Vmax values for the high-affinity system were 4.20 x 10(-8) M and 7.59 fmol/10 mg wet weight/min, respectively, whereas these values for the low-affinity system were 1.00 x 10(-6) M and 100 fmol/10 mg wet weight/min, respectively. In the spinal cord, there was only one uptake system, with a Km value of 2.16 x 10(-7) M and Vmax value of 26.2 fmol/10 mg wet weight/min. These results suggest that when SP is released from nerve terminals, it is hydrolysed into (5-11)SP before or after acting as a neurotransmitter, which is in turn accumulated into nerve terminals. Therefore, the uptake system may represent a possible mechanism for the inactivation of SP.

  6. The Influence of Fatty Acid Methyl Esters (FAMEs) in the Biochemistry and the Na(+)/K(+)-ATPase Activity of Culex quinquefasciatus Larvae.

    Science.gov (United States)

    Silva, Lilian N D; Ribeiro-Neto, José A; Valadares, Jéssica M M; Costa, Mariana M; Lima, Luciana A R S; Grillo, Luciano A M; Cortes, Vanessa F; Santos, Herica L; Alves, Stênio N; Barbosa, Leandro A

    2016-08-01

    Culex quinquefasciatus is the main vector of lymphatic filariasis and combating this insect is of great importance to public health. There are reports of insects that are resistant to the products currently used to control this vector, and therefore, the search for new products has increased. In the present study, we have evaluated the effects of fatty acid methyl esters (FAMEs) that showed larvicidal activity against C. quinquefasciatus, on glucose, total protein, and triacylglycerol contents and Na(+)/K(+)-ATPase activity in mosquito larvae. The exposure of the fourth instar larvae to the compounds caused a decrease in the total protein content and an increase in the activity of the Na(+)/K(+)-ATPase. Furthermore, the direct effect of FAMEs on cell membrane was assessed on purified pig kidney Na(+)/K(+)-ATPase membranes, erythrocyte ghost membranes, and larvae membrane preparation. No modifications on total phospholipids and cholesterol content were found after FAMEs 20 min treatment on larvae membrane preparation, but only 360 µg/mL FAME 2 was able to decrease total phospholipid of erythrocyte ghost membrane. Moreover, only 60 and 360 µg/mL FAME 3 caused an activation of purified Na(+)/K(+)-ATPase, that was an opposite effect of FAMEs treatment in larvae membrane preparation, and caused an inhibition of the pump activity. These data together suggest that maybe FAMEs can modulate the Na(+)/K(+)-ATPase on intact larvae for such mechanisms and not for a direct effect, one time that the direct effect of FAMEs in membrane preparation decreased the activity of Na(+)/K(+)-ATPase. The biochemical changes caused by the compounds were significant and may negatively influence the development and survival of C. quinquefasciatus larvae.

  7. Aspartame-fed zebrafish exhibit acute deaths with swimming defects and saccharin-fed zebrafish have elevation of cholesteryl ester transfer protein activity in hypercholesterolemia.

    Science.gov (United States)

    Kim, Jae-Yong; Seo, Juyi; Cho, Kyung-Hyun

    2011-11-01

    Although many artificial sweeteners (AS) have safety issues, the AS have been widely used in industry. To determine the physiologic effect of AS in the presence of hyperlipidemia, zebrafish were fed aspartame or saccharin with a high-cholesterol diet (HCD). After 12 days, 30% of zebrafish, which consumed aspartame and HCD, died with exhibiting swimming defects. The aspartame group had 65% survivability, while the control and saccharin groups had 100% survivability. Under HCD, the saccharin-fed groups had the highest increase in the serum cholesterol level (599 mg/dL). Aspartame-fed group showed a remarkable increase in serum glucose (up to 125 mg/dL), which was 58% greater than the increase in the HCD alone group. The saccharin and HCD groups had the highest cholesteryl ester transfer protein (CETP) activity (52% CE-transfer), while the HCD alone group had 42% CE-transfer. Histologic analysis revealed that the aspartame and HCD groups showed more infiltration of inflammatory cells in the brain and liver sections. Conclusively, under presence of hyperlipidemia, aspartame-fed zebrafish exhibited acute swimming defects with an increase in brain inflammation. Saccharin-fed zebrafish had an increased atherogenic serum lipid profile with elevation of CETP activity. Copyright © 2011 Elsevier Ltd. All rights reserved.

  8. Yeast: the soul of beer's aroma--a review of flavour-active esters and higher alcohols produced by the brewing yeast.

    Science.gov (United States)

    Pires, Eduardo J; Teixeira, José A; Brányik, Tomás; Vicente, António A

    2014-03-01

    Among the most important factors influencing beer quality is the presence of well-adjusted amounts of higher alcohols and esters. Thus, a heavy body of literature focuses on these substances and on the parameters influencing their production by the brewing yeast. Additionally, the complex metabolic pathways involved in their synthesis require special attention. More than a century of data, mainly in genetic and proteomic fields, has built up enough information to describe in detail each step in the pathway for the synthesis of higher alcohols and their esters, but there is still place for more. Higher alcohols are formed either by anabolism or catabolism (Ehrlich pathway) of amino acids. Esters are formed by enzymatic condensation of organic acids and alcohols. The current paper reviews the up-to-date knowledge in the pathways involving the synthesis of higher alcohols and esters by brewing yeasts. Fermentation parameters affecting yeast response during biosynthesis of these aromatic substances are also fully reviewed.

  9. Selective Reductive Removal of Ester and Amide Groups from Arenes and Heteroarenes through Nickel-Catalyzed C−O and C−N Bond Activation

    KAUST Repository

    Yue, Huifeng

    2017-03-21

    An inexpensive nickel(II) catalyst and a hydrosilane were used for the efficient reductive defunctionalization of aryl and heteroaryl esters through a decarbonylative pathway. This versatile method could be used for the removal of ester and amide functional groups from various organic molecules. Moreover, a scale-up experiment and a synthetic application based on the use of a removable carboxylic acid directing group highlight the usefulness of this reaction.

  10. Selective Reductive Removal of Ester and Amide Groups from Arenes and Heteroarenes through Nickel-Catalyzed C−O and C−N Bond Activation

    KAUST Repository

    Yue, Huifeng; Guo, Lin; Lee, Shao-Chi; Liu, Xiangqian; Rueping, Magnus

    2017-01-01

    An inexpensive nickel(II) catalyst and a hydrosilane were used for the efficient reductive defunctionalization of aryl and heteroaryl esters through a decarbonylative pathway. This versatile method could be used for the removal of ester and amide functional groups from various organic molecules. Moreover, a scale-up experiment and a synthetic application based on the use of a removable carboxylic acid directing group highlight the usefulness of this reaction.

  11. Experimental study of the anti-tumour activity and pharmacokinetics of arctigenin and its valine ester derivative

    OpenAIRE

    Cai, Enbo; Song, Xingzhuo; Han, Mei; Yang, Limin; Zhao, Yan; Li, Wei; Han, Jiahong; Tu, Shumei

    2018-01-01

    Arctigenin (ARG) is a functional active component that has important physiological and pharmacological activities. The anti-tumour and anti-inflammatory activities of ARG show good potential for application and development, but this material has the defect of low water solubility. In this experiment, the valine derivative of ARG (ARG-V) was designed and synthesized to overcome this disadvantage. The ARG amino acid, EDCI and DMAP were raw materials in the addition reaction, with a molar ratio ...

  12. Amino-terminal extension present in the methionine aminopeptidase type 1c of Mycobacterium tuberculosis is indispensible for its activity

    Directory of Open Access Journals (Sweden)

    Kumaran Sangaralingam

    2011-07-01

    Full Text Available Abstract Background Methionine aminopeptidase (MetAP is a ubiquitous enzyme in both prokaryotes and eukaryotes, which catalyzes co-translational removal of N-terminal methionine from elongating polypeptide chains during protein synthesis. It specifically removes the terminal methionine in all organisms, if the penultimate residue is non-bulky and uncharged. The MetAP action for exclusion of N-terminal methionine is mandatory in 50-70% of nascent proteins. Such an activity is required for proper sub cellular localization, additional processing and eventually for the degradation of proteins. Results We cloned genes encoding two such metalloproteases (MtMetAP1a and MtMetAP1c present in Mycobacterium tuberculosis and expressed them as histidine-tagged proteins in Escherichia coli. Although they have different substrate preferences, for Met-Ala-Ser, we found, MtMetAP1c had significantly high enzyme turnover rate as opposed to MtMetAP1a. Circular dichroism spectroscopic studies as well as monitoring of enzyme activity indicated high temperature stability (up to 50°C of MtMetAP1a compared to that of the MtMetAP1c. Modelling of MtMetAP1a based on MtMetAP1c crystal structure revealed the distinct spatial arrangements of identical active site amino acid residues and their mutations affected the enzymatic activities of both the proteins. Strikingly, we observed that 40 amino acid long N-terminal extension of MtMetAP1c, compared to its other family members, contributes towards the activity and stability of this enzyme, which has never been reported for any methionine aminopeptidase. Furthermore, mutational analysis revealed that Val-18 and Pro-19 of MtMetAP1c are crucial for its enzymatic activity. Consistent with this observation, molecular dynamic simulation studies of wild-type and these variants strongly suggest their involvement in maintaining active site conformation of MtMetAP1c. Conclusion Our findings unequivocally emphasized that N-terminal

  13. Protein kinase C activation decreases cell surface expression of the GLT-1 subtype of glutamate transporter. Requirement of a carboxyl-terminal domain and partial dependence on serine 486.

    Science.gov (United States)

    Kalandadze, Avtandil; Wu, Ying; Robinson, Michael B

    2002-11-29

    Na(+)-dependent glutamate transporters are required for the clearance of extracellular glutamate and influence both physiological and pathological effects of this excitatory amino acid. In the present study, the effects of a protein kinase C (PKC) activator on the cell surface expression and activity of the GLT-1 subtype of glutamate transporter were examined in two model systems, primary co-cultures of neurons and astrocytes that endogenously express GLT-1 and C6 glioma cells transfected with GLT-1. In both systems, activation of PKC with phorbol ester caused a decrease in GLT-1 cell surface expression. This effect is opposite to the one observed for the EAAC1 subtype of glutamate transporter (Davis, K. E., Straff, D. J., Weinstein, E. A., Bannerman, P. G., Correale, D. M., Rothstein, J. D., and Robinson, M. B. (1998) J. Neurosci. 18, 2475-2485). Several recombinant chimeric proteins between GLT-1 and EAAC1 transporter subtypes were generated to identify domains required for the subtype-specific redistribution of GLT-1. We identified a carboxyl-terminal domain consisting of 43 amino acids (amino acids 475-517) that is required for PKC-induced GLT-1 redistribution. Mutation of a non-conserved serine residue at position 486 partially attenuated but did not completely abolish the PKC-dependent redistribution of GLT-1. Although we observed a phorbol ester-dependent incorporation of (32)P into immunoprecipitable GLT-1, mutation of serine 486 did not reduce this signal. We also found that chimeras containing the first 446 amino acids of GLT-1 were not functional unless amino acids 475-517 of GLT-1 were also present. These non-functional transporters were not as efficiently expressed on the cell surface and migrated to a smaller molecular weight, suggesting that a subtype-specific interaction is required for the formation of functional transporters. These studies demonstrate a novel effect of PKC on GLT-1 activity and define a unique carboxyl-terminal domain as an

  14. Downstream signaling mechanism of the C-terminal activation domain of transcriptional coactivator CoCoA

    OpenAIRE

    Kim, Jeong Hoon; Yang, Catherine K.; Stallcup, Michael R.

    2006-01-01

    The coiled-coil coactivator (CoCoA) is a transcriptional coactivator for nuclear receptors and enhances nuclear receptor function by the interaction with the bHLH-PAS domain (AD3) of p160 coactivators. The C-terminal activation domain (AD) of CoCoA possesses strong transactivation activity and is required for the coactivator function of CoCoA with nuclear receptors. To understand how CoCoA AD transmits its activating signal to the transcription machinery, we defined specific subregions, amino...

  15. Quantitation using a stable isotope dilution assay (SIDA) and thresholds of taste-active pyroglutamyl decapeptide ethyl esters (PGDPEs) in sake.

    Science.gov (United States)

    Hashizume, Katsumi; Ito, Toshiko; Igarashi, Shinya

    2017-03-01

    A stable isotope dilution assay (SIDA) for two taste-active pyroglutamyl decapeptide ethyl esters (PGDPE1; (pGlu)LFGPNVNPWCOOC 2 H 5 , PGDPE2; (pGlu)LFNPSTNPWCOOC 2 H 5 ) in sake was developed using deuterated isotopes and high-resolution mass spectrometry. Recognition thresholds of PGDPEs in sake were estimated as 3.8 μg/L for PGDPE1 and 8.1 μg/L for PGDPE2, evaluated using 11 student panelists aged in their twenties. Quantitated concentrations in 18 commercial sake samples ranged from 0 to 27 μg/L for PGDPE1 and from 0 to 202 μg/L for PGDPE2. The maximum levels of PGDPE1 and PGDPE2 in the sake samples were approximately 8 and 25 times higher than the estimated recognition thresholds, respectively. The results indicated that PGDPEs may play significant sensory roles in the sake. The level of PGDPEs in unpasteurized sake samples decreased during storage for 50 days at 6 °C, suggesting PGDPEs may be enzymatically decomposed.

  16. Improved activity of lipase immobilized in microemulsion-based organogels for (R, S-ketoprofen ester resolution: Long-term stability and reusability

    Directory of Open Access Journals (Sweden)

    Wei-Wei Zhang

    2015-09-01

    Full Text Available Microemulsion-based organogels (MBGs were effectively employed for the immobilization of four commonly used lipases. During the asymmetric hydrolysis of ketoprofen vinyl ester at 30 °C for 24 h, lipase from Rhizomucor miehei and Mucor javanicus immobilized in microemulsion-based organogels (RML MBGs and MJL MBGs maintained good enantioselectivities (eep were 86.2% and 99.2%, respectively, and their activities increased 12.8-fold and 7.8-fold, respectively, compared with their free forms. They gave higher yields compared with other lipase MBGs and exhibited better enantioselectivity than commercial immobilized lipases. Immobilization considerably increased the tolerance to organic solvents and high temperature. Both MJL MBGs and RML MBGs showed excellent reusability during 30 cycles of repeated 24 h reactions at 30 °C (over 40 days. The system maintained yields of greater than 50%, while the ees values of RML MBGs and MJL MBGs remained nearly constant at 95% and 88%, respectively.

  17. The proapoptotic activity of C-terminal domain of apoptosis-inducing factor (AIF is separated from its N-terminal

    Directory of Open Access Journals (Sweden)

    YONG ZHANG

    2009-01-01

    Full Text Available Apoptosis-inducing factor (AIF is a mitochondrial flavoprotein that mediates both NADH-oxidizing and caspase-independent apoptosis. Further, the proapoptotic activity of AIF is located in the C-terminus of AIF, although the precise minimum sequence responsible for apoptosis induction remains to be investigated. In the present study, we generated two truncated AIFs, AIFΔ1-480-FLAG, which is a FLAG-tagged C-terminal peptide comprising amino acids from 481 to 613, and AIF360-480 containing amino acids from 360 to 480 of AIF. We used confocal microscopy to demonstrate that both the truncated proteins are expressed and located in the cytoplasm of transfected cells. AIFΔ1-480 but not AIF360-480 induces apoptosis in transfected cells. We also found that the expression of AIFΔ1-480 could initiate the release of cytochrome c from the mitochondria. The suppression of caspase-9 via siRNA blocked the proapoptotic activity of AIFΔ1-480. Therefore, AIFΔ 1-480 is sufficient for inducing caspase-9-dependent apoptotic signaling, probably by promoting the release of cytochrome c. At last, we generated a chimeric immuno-AIFΔ 1-480 protein, which comprised an HER2 antibody, a Pseudomonas exotoxin A translocation domain and AIFΔ 1-480. Human Jurkat cells transfected with the immuno-AIFΔl-480 gene could express and secrete the chimeric protein, which selectively recognize and kill HER2-overexpressing tumor cells. Our study demonstrates the feasibility of the immuno-AIFΔl-480 gene as a novel approach to treating HER2-overexpressing cancers.

  18. Comparative evaluation of antibacterial activity of caffeic acid phenethyl ester and PLGA nanoparticle formulation by different methods

    International Nuclear Information System (INIS)

    Arasoglu, Tülin; Mansuroglu, Banu; Derman, Serap

    2016-01-01

    The aim of the present study was to evaluate the antimicrobial activity of nanoparticle and free formulations of the CAPE compound using different methods and comparing the results in the literature for the first time. In parallel with this purpose, encapsulation of CAPE with the PLGA nanoparticle system (CAPE-PLGA-NPs) and characterization of nanoparticles were carried out. Afterwards, antimicrobial activity of free CAPE and CAPE-PLGA-NPs was determined using agar well diffusion, disk diffusion, broth microdilution and reduction percentage methods. P. aeroginosa, E. coli, S. aureus and methicillin-resistant S. aureus (MRSA) were chosen as model bacteria since they have different cell wall structures. CAPE-PLGA-NPs within the range of 214.0 ± 8.80 nm particle size and with an encapsulation efficiency of 91.59 ± 4.97% were prepared using the oil-in-water (o–w) single-emulsion solvent evaporation method. The microbiological results indicated that free CAPE did not have any antimicrobial activity in any of the applied methods whereas CAPE-PLGA-NPs had significant antimicrobial activity in both broth dilution and reduction percentage methods. CAPE-PLGA-NPs showed moderate antimicrobial activity against S. aureus and MRSA strains particularly in hourly measurements at 30.63 and 61.25 μg ml −1 concentrations (both p < 0.05), whereas they failed to show antimicrobial activity against Gram-negative bacteria (P. aeroginosa and E. coli, p > 0.05). In the reduction percentage method, in which the highest results of antimicrobial activity were obtained, it was observed that the antimicrobial effect on S. aureus was more long-standing (3 days) and higher in reduction percentage (over 90%). The appearance of antibacterial activity of CAPE-PLGA-NPs may be related to higher penetration into cells due to low solubility of free CAPE in the aqueous medium. Additionally, the biocompatible and biodegradable PLGA nanoparticles could be an alternative to solvents such as

  19. Adsorptive removal of phthalate ester (Di-ethyl phthalate) from aqueous phase by activated carbon: a kinetic study.

    Science.gov (United States)

    Venkata Mohan, S; Shailaja, S; Rama Krishna, M; Sarma, P N

    2007-07-19

    Adsorptive studies were carried out on Di-ethyl phthalate (DEP) removal from aqueous phase onto activated carbon. Batch sorption studies were performed and the results revealed that activated carbon demonstrated ability to adsorb DEP. Influence of varying experimental conditions such as DEP concentration, pH of aqueous solution, and dosage of adsorbent were investigated on the adsorption process. Sorption interaction of DEP onto activated carbon obeyed the pseudo second order rate equation. Experimental data showed good fit with both the Langmuir and Freundlich adsorption isotherm models. DEP sorption was found to be dependent on the aqueous phase pH and the uptake was observed to be greater at acidic pH.

  20. Comparative evaluation of antibacterial activity of caffeic acid phenethyl ester and PLGA nanoparticle formulation by different methods

    Science.gov (United States)

    Arasoglu, Tülin; Derman, Serap; Mansuroglu, Banu

    2016-01-01

    The aim of the present study was to evaluate the antimicrobial activity of nanoparticle and free formulations of the CAPE compound using different methods and comparing the results in the literature for the first time. In parallel with this purpose, encapsulation of CAPE with the PLGA nanoparticle system (CAPE-PLGA-NPs) and characterization of nanoparticles were carried out. Afterwards, antimicrobial activity of free CAPE and CAPE-PLGA-NPs was determined using agar well diffusion, disk diffusion, broth microdilution and reduction percentage methods. P. aeroginosa, E. coli, S. aureus and methicillin-resistant S. aureus (MRSA) were chosen as model bacteria since they have different cell wall structures. CAPE-PLGA-NPs within the range of 214.0 ± 8.80 nm particle size and with an encapsulation efficiency of 91.59 ± 4.97% were prepared using the oil-in-water (o-w) single-emulsion solvent evaporation method. The microbiological results indicated that free CAPE did not have any antimicrobial activity in any of the applied methods whereas CAPE-PLGA-NPs had significant antimicrobial activity in both broth dilution and reduction percentage methods. CAPE-PLGA-NPs showed moderate antimicrobial activity against S. aureus and MRSA strains particularly in hourly measurements at 30.63 and 61.25 μg ml-1 concentrations (both p 0.05). In the reduction percentage method, in which the highest results of antimicrobial activity were obtained, it was observed that the antimicrobial effect on S. aureus was more long-standing (3 days) and higher in reduction percentage (over 90%). The appearance of antibacterial activity of CAPE-PLGA-NPs may be related to higher penetration into cells due to low solubility of free CAPE in the aqueous medium. Additionally, the biocompatible and biodegradable PLGA nanoparticles could be an alternative to solvents such as ethanol, methanol or DMSO. Consequently, obtained results show that the method of selection is extremely important and will influence the

  1. QSAR for cholinesterase inhibition by organophosphorus esters and CNDO/2 calculations for organophosphorus ester hydrolysis

    Science.gov (United States)

    Johnson, H.; Kenley, R. A.; Rynard, C.; Golub, M. A.

    1985-01-01

    Quantitative structure-activity relationships were derived for acetyl- and butyrylcholinesterase inhibition by various organophosphorus esters. Bimolecular inhibition rate constants correlate well with hydrophobic substituent constants, and with the presence or absence of catonic groups on the inhibitor, but not with steric substituent constants. CNDO/2 calculations were performed on a separate set of organophosphorus esters, RR'P(O)X, where R and R' are alkyl and/or alkoxy groups and X is fluorine, chlorine or a phenoxy group. For each subset with the same X, the CNDO-derived net atomic charge at the central phosphorus atom in the ester correlates well with the alkaline hydrolysis rate constant. For the whole set of esters with different X, two equations were derived that relate either charge and leaving group steric bulk, or orbital energy and bond order to the hydrogen hydrolysis rate constant.

  2. Experimental study of the anti-tumour activity and pharmacokinetics of arctigenin and its valine ester derivative.

    Science.gov (United States)

    Cai, Enbo; Song, Xingzhuo; Han, Mei; Yang, Limin; Zhao, Yan; Li, Wei; Han, Jiahong; Tu, Shumei

    2018-02-19

    Arctigenin (ARG) is a functional active component that has important physiological and pharmacological activities. The anti-tumour and anti-inflammatory activities of ARG show good potential for application and development, but this material has the defect of low water solubility. In this experiment, the valine derivative of ARG (ARG-V) was designed and synthesized to overcome this disadvantage. The ARG amino acid, EDCI and DMAP were raw materials in the addition reaction, with a molar ratio of 1:2:2:0.5. The yield of ARG-V was up to 80%. ARG-V has strong anti-tumour activity in vivo and in vitro. The inhibitory rate of ARG-V was 69.2%, with less damage to the immune organs and different degrees of increased serum cytotoxicity. Moreover, the pharmacokinetics of ARG following oral administration and ARG-V following oral administration in rats were also studied. The C max and AUC values of ARG-V showed significant differences compared to ARG. The relative bioavailabilities of three doses of ARG-V compared to ARG were 664.7%, 741.5% and 812.9%. These pharmacokinetic results may be useful for further studies of the bioactive mechanism of ARG and provide a theoretical basic for clinical use.

  3. Photodynamic action of LED-activated pyropheophorbide-α methyl ester in cisplatin-resistant human ovarian carcinoma cells

    International Nuclear Information System (INIS)

    Tan, Y; Xia, X S; Yu, H P; Bai, D Q; He, Y; Xu, C S; Leung, A W N

    2009-01-01

    Cisplatin-resistance is a major obstacle for the successful therapy to ovarian cancer, and exploring novel approach to deactivate cisplatin-resistant ovarian cells will improve the clinical outcomes. Our present study showed that there was no dark cytotoxicity of MPPa in the COC1/DDP cells at the dose of 0.25 – 4 μM, and LED-activated MPPa resulted in drug dose- and light-dependent cytotoxicity. Apoptotic rate 6 h after LED-activated MPPa (2 μM) increased to 16.71% under the light energy of 1 J/cm 2 . Confocal laser scanning microscopy showed that MPPa mainly localized in the intracellular membrane system, namely the endoplasmic reticulum, Golgi apparatus, lysosomes and mitochondria in the COC1/DDP cells. Mitochondrial membrane potential (ΔΨ m ) was collapsed when COC1/DDP cells were exposed to 2 μM MPPa for 20 h and then 1 J/cm 2 irradiation of LED source. These data demonstrated that LED-activated MPPa significantly deactivated cisplatin-resistant ovarian cell line COC1/DDP cells and enhanced apoptosis and decreased ΔΨ m , which suggests LED is an efficient light source for PDT and LED-activated MPPa can be developed as new modality for treating cisplatin-resistant ovarian

  4. The Croton megalobotrys Müll Arg. traditional medicine in HIV/AIDS management: Documentation of patient use, in vitro activation of latent HIV-1 provirus, and isolation of active phorbol esters.

    Science.gov (United States)

    Tietjen, Ian; Ngwenya, Barbara N; Fotso, Ghislain; Williams, David E; Simonambango, Sundana; Ngadjui, Bonaventure T; Andersen, Raymond J; Brockman, Mark A; Brumme, Zabrina L; Andrae-Marobela, Kerstin

    2018-01-30

    Current HIV therapies do not act on latent cellular HIV reservoirs; hence they are not curative. While experimental latency reversal agents (LRAs) can promote HIV expression in these cells, thereby exposing them to immune recognition, existing LRAs exhibit limited clinical efficacy and high toxicity. We previously described a traditional 3-step medicinal plant regimen used for HIV/AIDS management in Northern Botswana that inhibits HIV replication in vitro. Here we describe use of one component of the regimen that additionally contains novel phorbol esters possessing HIV latency-reversal properties. We sought to document experiences of traditional medicine users, assess the ability of traditional medicine components to reverse HIV latency in vitro, and identify pure compounds that conferred these activities. Experiences of two HIV-positive traditional medicine users (patients) were documented using qualitative interview techniques. Latency reversal activity was assessed using a cell-based model (J-Lat, clone 9.2). Crude plant extracts were fractionated by open column chromatography and reverse-phase HPLC. Compound structures were elucidated using NMR spectroscopy and mass spectrometry. Patients using the 3-step regimen reported improved health over several years despite no reported use of standard HIV therapies. Crude extracts from Croton megalobotrys Müll Arg. ("Mukungulu"), the third component of the 3-step regimen, induced HIV expression in J-lat cells to levels comparable to the known LRA prostratin. Co-incubation with known LRAs and pharmacological inhibitors indicated that the active agent(s) in C. megalobotrys were likely to be protein kinase C (PKC) activator(s). Consistent with these results, two novel phorbol esters (Namushen 1 and 2) were isolated as abundant components of C. megalobotrys and were sufficient to confer HIV latency reversal in vitro. We have identified novel LRAs of the phorbol ester class from a medicinal plant used in HIV/AIDS management

  5. Alternative Production of Fatty Acid Methyl Esters from Triglycerides ...

    African Journals Online (AJOL)

    The catalysts activity was tested in thermocatalytic cracking of triglyceride; a direct conversion process for fatty acid methyl esters (biodiesel). The SZ1 not only exhibited higher conversion of triglycerides but higher fatty acid methyl esters (FAMEs) yields of approximately 59% after 3h as compared to SZ2 (32%). In addition ...

  6. Carboxy terminal region of the Fanconi anemia protein, FANCG/XRCC9, is required for functional activity.

    Science.gov (United States)

    Kuang, Y; Garcia-Higuera, I; Moran, A; Mondoux, M; Digweed, M; D'Andrea, A D

    2000-09-01

    Fanconi anemia (FA) is an autosomal recessive cancer susceptibility syndrome with eight complementation groups. Four of the FA genes have been cloned, and at least three of the encoded proteins, FANCA, FANCC, and FANCG/XRCC9, interact in a nuclear complex, required for the maintenance of normal chromosome stability. In the current study, mutant forms of the FANCA and FANCG proteins have been generated and analyzed with respect to protein complex formation, nuclear translocation, and functional activity. The results demonstrate that the amino terminal two-thirds of FANCG (FANCG amino acids 1-428) binds to the amino terminal nuclear localization signal (NLS) of the FANCA protein. On the basis of 2-hybrid analysis, the FANCA/FANCG binding is a direct protein-protein interaction. Interestingly, a truncated mutant form of the FANCG protein, lacking the carboxy terminus, binds in a complex with FANCA and translocates to the nucleus; however, this mutant protein fails to bind to FANCC and fails to correct the mitomycin C sensitivity of an FA-G cell line. Taken together, these results demonstrate that binding of FANCG to the amino terminal FANCA NLS sequence is necessary but not sufficient for the functional activity of FANCG. Additional amino acid sequences at the carboxy terminus of FANCG are required for the binding of FANCC in the complex. (Blood. 2000;96:1625-1632)

  7. Cholinesterase inhibitory activity and structure elucidation of a new phytol derivative and a new cinnamic acid ester from Pycnanthus angolensis

    Directory of Open Access Journals (Sweden)

    Taiwo O. Elufioye

    Full Text Available ABSTRACT The leaves of Pycnanthus angolensis (Welw. Warb., Myristicaceae, are used as memory enhancer and anti-ageing in Nigerian ethnomedicine. This study aimed at evaluating the cholinesterase inhibitory property as well as isolates the bioactive compounds from the plant. The acetylcholinesterase and butyrylcholinesterase inhibitory potentials of extracts, fractions, and isolated compounds were evaluated by colorimetric and TLC bioautographic assay techniques. The extract inhibited both enzymes with activity increasing with purification, ethyl acetate fraction being most active fraction at 65.66 ± 1.06% and 49.38 ± 1.66% against acetylcholinesterase and butyrylcholinesterase, respectively while the supernatant had 77.44 ± 1.18 inhibition against acetylcholinesterase. Two new bioactive compounds, (2E, 18E-3,7,11,15,18-pentamethylhenicosa-2,18-dien-1-ol (named eluptol and [12-(4-hydroxy-3-methyl-oxo-cyclopenta-1,3-dien-1yl-11-methyl-dodecyl](E-3-(3,4-dimethylphenylprop-2-enoate (named omifoate A were isolated from the plant with IC50 of 22.26 µg/ml (AChE, 34.61 µg/ml (BuChE and 6.51 µg/ml (AChE, 9.07 µg/ml (BuChE respectively. The results showed that the plant has cholinesterase inhibitory activity which might be responsible for its memory enhancing action, thus justifying its inclusion in traditional memory enhancing preparations

  8. Apoptotic Activity of MeCP2 Is Enhanced by C-Terminal Truncating Mutations.

    Directory of Open Access Journals (Sweden)

    Alison A Williams

    Full Text Available Methyl-CpG binding protein 2 (MeCP2 is a widely abundant, multifunctional protein most highly expressed in post-mitotic neurons. Mutations causing Rett syndrome and related neurodevelopmental disorders have been identified along the entire MECP2 locus, but symptoms vary depending on mutation type and location. C-terminal mutations are prevalent, but little is known about the function of the MeCP2 C-terminus. We employ the genetic efficiency of Drosophila to provide evidence that expression of p.Arg294* (more commonly identified as R294X, a human MECP2 E2 mutant allele causing truncation of the C-terminal domains, promotes apoptosis of identified neurons in vivo. We confirm this novel finding in HEK293T cells and then use Drosophila to map the region critical for neuronal apoptosis to a small sequence at the end of the C-terminal domain. In vitro studies in mammalian systems previously indicated a role of the MeCP2 E2 isoform in apoptosis, which is facilitated by phosphorylation at serine 80 (S80 and decreased by interactions with the forkhead protein FoxG1. We confirm the roles of S80 phosphorylation and forkhead domain transcription factors in affecting MeCP2-induced apoptosis in Drosophila in vivo, thus indicating mechanistic conservation between flies and mammalian cells. Our findings are consistent with a model in which C- and N-terminal interactions are required for healthy function of MeCP2.

  9. Tissue factor pathway inhibitor 2 is found in skin and its C-terminal region encodes for antibacterial activity.

    Science.gov (United States)

    Papareddy, Praveen; Kalle, Martina; Sørensen, Ole E; Lundqvist, Katarina; Mörgelin, Matthias; Malmsten, Martin; Schmidtchen, Artur

    2012-01-01

    Tissue factor pathway inhibitor 2 (TFPI-2) is a matrix-associated serine protease inhibitor with an enigmatic function in vivo. Here, we describe that TFPI-2 is present in fibrin of wounds and also expressed in skin, where it is up-regulated upon wounding. Neutrophil elastase cleaved TFPI-2, and a C-terminal fragment was found to bind to bacteria. Similarly, a prototypic peptide representing this C-terminal part, EDC34, bound to bacteria and bacterial lipopolysaccharide, and induced bacterial permeabilization. The peptide also induced leakage in artificial liposomes, and displayed a random coil conformation upon interactions with liposomes as well as lipopolysaccharide. EDC34 was antibacterial against both Gram-negative and Gram-positive bacteria in physiological buffer conditions. The results demonstrate that the C-terminus of TFPI-2 encodes for antimicrobial activity, and may be released during wounding.

  10. Adsorption Removal of Glycidyl Esters from Palm Oil and Oil Model Solution by Using Acid-Washed Oil Palm Wood-Based Activated Carbon: Kinetic and Mechanism Study.

    Science.gov (United States)

    Cheng, Weiwei; Liu, Guoqin; Wang, Xuede; Han, Lipeng

    2017-11-08

    Acid-washed oil palm wood-based activated carbon (OPAC) has been investigated for its potential application as a promising adsorbent in the removal of glycidyl esters (GEs) from both palm oil and oil model (hexadecane) solution. It was observed that the removal rate of GEs in palm oil was up to >95%, which was significantly higher than other adsorbents used in this study. In batch adsorption system, the adsorption efficiency and performance of acid-washed OPAC were evaluated as a function of several experimental parameters such as contact time, initial glycidyl palmitate (PGE) concentration, adsorbent dose, and temperature. The Langmuir, Freundlich, and Dubinin-Radushkevich models were used to describe the adsorption equilibrium isotherm, and the equilibrium data were fitted best by the Langmuir model. The maximum adsorption capacity of acid-washed OPAC was found to be 36.23 mg/g by using the Langmuir model. The thermodynamic analysis indicated that the adsorption of PGE on acid-washed OPAC was an endothermic and physical process in nature. The experimental data were fitted by using pseudo-first-order, pseudo-second-order, and intraparticle diffusion models. It was found that the kinetic of PGE adsorption onto acid-washed OPAC followed well the pseudo-second-order model for various initial PGE concentrations and the adsorption process was controlled by both film diffusion and intraparticle diffusion. The desorption test indicated the removal of GEs from palm oil was attributed to not only the adsorption of GEs on acid-washed OPAC, but also the degradation of GEs adsorbed at activated sites with acidic character. Furthermore, no significant difference between before and after PGE adsorption in oil quality was observed.

  11. Computer-assisted molecular modeling of tumor promoters: rationale for the activity of phorbol esters, teleocidin B, and aplysiatoxin

    International Nuclear Information System (INIS)

    Jeffrey, A.M.; Liskamp, R.M.J.

    1986-01-01

    In the two-stage model of skin carcinogenesis, it is believed that initiators bind to DNA and that tumor promoters such as phorbol 12-tetradecanoate 13-acetate (TPA) bind noncovalently to membrane-associated high-affinity receptors, probably protein kinase C. Two other types of potent tumor-promoting substances, aplysiatoxin and teleocidin, appear to act also by binding to and activating protein kinase C, even though their chemical structures are quite different. Therefore, the authors have undertaken computer modeling of the special relationship of various functional groups in these three chemical classes of tumor promoters in an attempt to explain how these diverse structures bind to the same receptor molecule. They propose a stereochemical model in which the oxygens in TPA at C-3, C-4, C-9, and C-20 (O-3, O-4, O-9, and O-20) correspond to the O-11, N-13, N-1, and O-24 positions in teleocidin and the O-27, O-3, O-11, and O-30 oxygens in aplysiatoxin, respectively. In this model all distances with respect to overlap of the corresponding atoms are <1 A. In addition, all three types of molecules have their hydrophobic moieties oriented in the similar position. This model is further discussed with respect to other compounds showing various degrees of activity as tumor promoters, including mezerein, ingenol, and 4α-TPA. The model explains how chemically diverse structures can have similar biological activity as tumor promoters and provides a basis for designing both agonists and antagonists of tumor promoters

  12. Triphenyltin derivatives of sulfanylcarboxylic esters.

    Science.gov (United States)

    Casas, José S; Couce, María D; Sánchez, Agustín; Seoane, Rafael; Sordo, José; Perez-Estévez, Antonio; Vázquez-López, Ezequiel

    2018-03-01

    The reaction of 3-(aryl)-2-sulfanylpropenoic acids [H 2 xspa; x: p=3-phenyl-, f=3-(2-furyl)-, t=3-(2-thienyl)-] with methanol or ethanol gave the corresponding methyl (Hxspme) or ethyl (Hxspee) esters. The reaction of these esters (HL) with triphenyltin(IV) hydroxide gave compounds of the type [SnPh 3 L], which were isolated and characterized as solids by elemental analysis, IR spectroscopy and mass spectrometry and in solution by multinuclear ( 1 H, 13 C and 119 Sn) NMR spectroscopy. The structures of [SnPh 3 (pspme)], [SnPh 3 (fspme)] and [SnPh 3 (fspee)] were determined by X-ray diffractometry and the antimicrobial activity against E. coli, S. aureus, B. subtilis, P. aeruginosa, Resistant P. aeruginosa (a strain resistant to 'carbapenem'), and C. albicans was tested and the in vitro cytotoxic activity against the HeLa-229, A2780 and A2780cis cell lines was determined for all compounds. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Hyperpolarization-activated current (I(h)) in vestibular calyx terminals: characterization and role in shaping postsynaptic events.

    Science.gov (United States)

    Meredith, Frances L; Benke, Tim A; Rennie, Katherine J

    2012-12-01

    Calyx afferent terminals engulf the basolateral region of type I vestibular hair cells, and synaptic transmission across the vestibular type I hair cell/calyx is not well understood. Calyces express several ionic conductances, which may shape postsynaptic potentials. These include previously described tetrodotoxin-sensitive inward Na(+) currents, voltage-dependent outward K(+) currents and a K(Ca) current. Here, we characterize an inwardly rectifying conductance in gerbil semicircular canal calyx terminals (postnatal days 3-45), sensitive to voltage and to cyclic nucleotides. Using whole-cell patch clamp, we recorded from isolated calyx terminals still attached to their type I hair cells. A slowly activating, noninactivating current (I(h)) was seen with hyperpolarizing voltage steps negative to the resting potential. External Cs(+) (1-5 mM) and ZD7288 (100 μM) blocked the inward current by 97 and 83 %, respectively, confirming that I(h) was carried by hyperpolarization-activated, cyclic nucleotide gated channels. Mean half-activation voltage of I(h) was -123 mV, which shifted to -114 mV in the presence of cAMP. Activation of I(h) was well described with a third order exponential fit to the current (mean time constant of activation, τ, was 190 ms at -139 mV). Activation speeded up significantly (τ=136 and 127 ms, respectively) when intracellular cAMP and cGMP were present, suggesting that in vivo I(h) could be subject to efferent modulation via cyclic nucleotide-dependent mechanisms. In current clamp, hyperpolarizing current steps produced a time-dependent depolarizing sag followed by either a rebound afterdepolarization or an action potential. Spontaneous excitatory postsynaptic potentials (EPSPs) became larger and wider when I(h) was blocked with ZD7288. In a three-dimensional mathematical model of the calyx terminal based on Hodgkin-Huxley type ionic conductances, removal of I(h) similarly increased the EPSP, whereas cAMP slightly decreased simulated EPSP size

  14. Valyl benzyl ester chloride

    Directory of Open Access Journals (Sweden)

    Grzegorz Dutkiewicz

    2010-02-01

    Full Text Available In the title compound (systematic name: 1-benzyloxy-3-methyl-1-oxobutan-2-aminium chloride, C12H18NO2+·Cl−, the ester group is approximately planar, with a maximum deviation of 0.040 (2 Å from the least-squares plane, and makes a dihedral angle of 28.92 (16° with the phenyl ring. The crystal structure is organized by N—H...Cl hydrogen bonds which join the two components into a chain along the b axis. Pairs of chains arranged antiparallel are interconnected by further N—H...Cl hydrogen bonds, forming eight-membered rings. Similar packing modes have been observed in a number of amino acid ester halides with a short unit-cell parameter of ca 5.5 Å along the direction in which the chains run.

  15. Structure-activity studies with carboxy- and amino-terminal fragments of neurotensin on hypothalamic neurons in vitro.

    Science.gov (United States)

    Baldino, F; Davis, L G; Wolfson, B

    1985-09-09

    The purpose of this study was to determine the structural requirements for the activity of neurotensin (NT1-13) on preoptic/anterior hypothalamic (POAH) neurons in vitro. Standard explant culture electrophysiological techniques were employed. NT was administered to POAH cultures through the superfusion fluid, or, to the vicinity of individual neurons by pressure ejection (0.5-10 psi) from micropipettes. Computer-generated, peri-event histograms were used to quantitate neuronal responses. Pressure ejection of NT1-13 (50 pM to 1 microM) consistently produced an excitatory effect on 30 of 42 neurons. The remaining cells were either inhibited or unaffected. Application of the C-terminal hexapeptide, NT8-13, but not the N-terminal octapeptide, NT1-8 (less than or equal to 1 mM), produced an excitatory response in 21 of 30 neurons, but was less potent than NT1-13. Application of an N-acetylated NT8-13 fragment (NTAC8-13) produced a response that was similar to that produced by NT8-13. The excitatory effects of NT1-13 and NT8-13 were maintained in medium which effectively blocked synaptic transmission (0 mM Ca2+/12 mM Mg2+ 1 mM EGTA). These data indicate that the C-terminal hexapeptide, but not the N-terminal octapeptide, produces a dose-related, excitatory effect on single neurons in the POAH in vitro. The persistence of these effects in Ca2+-free medium supports a postsynaptic site of action for these peptides.

  16. Neurospora tryptophan synthase: N-terminal analysis and the sequence of the pyridoxal phosphate active site peptide

    International Nuclear Information System (INIS)

    Pratt, M.L.; Hsu, P.Y.; DeMoss, J.A.

    1986-01-01

    Tryptophan synthase (TS), which catalyzes the final step of tryptophan biosynthesis, is a multifunctional protein requiring pyridoxal phosphate (B6P) for two of its three distinct enzyme activities. TS from Neurospora has a blocked N-terminal, is a homodimer of 150 KDa and binds one mole of B6P per mole of subunit. The authors shown the N-terminal residue to be acyl-serine. The B6P-active site of holoenzyme was labelled by reduction of the B6P-Schiff base with [ 3 H]-NaBH 4 , and resulted in a proportionate loss of activity in the two B6P-requiring reactions. SDS-polyacrylamide gel electrophoresis of CNBr-generated peptides showed the labelled, active site peptide to be 6 KDa. The sequence of this peptide, purified to apparent homogeneity by a combination of C-18 reversed phase and TSK gel filtration HPLC is: gly-arg-pro-gly-gln-leu-his-lys-ala-glu-arg-leu-thr-glu-tyr-ala-gly-gly-ala-gln-ile-xxx-leu-lys-arg-glu-asp-leu-asn-his-xxx-gly-xxx-his-/sub ***/-ile-asn-asn-ala-leu. Although four residues (xxx, /sub ***/) are unidentified, this peptide is minimally 78% homologous with the corresponding peptide from yeast TS, in which residue (/sub ***/) is the lysine that binds B6P

  17. Single amino acids in the carboxyl terminal domain of aquaporin-1 contribute to cGMP-dependent ion channel activation

    Directory of Open Access Journals (Sweden)

    Yool Andrea J

    2003-10-01

    Full Text Available Abstract Background Aquaporin-1 (AQP1 functions as an osmotic water channel and a gated cation channel. Activation of the AQP1 ion conductance by intracellular cGMP was hypothesized to involve the carboxyl (C- terminus, based on amino acid sequence alignments with cyclic-nucleotide-gated channels and cGMP-selective phosphodiesterases. Results Voltage clamp analyses of human AQP1 channels expressed in Xenopus oocytes demonstrated that the nitric oxide donor, sodium nitroprusside (SNP; 3–14 mM activated the ionic conductance response in a dose-dependent manner. Block of soluble guanylate cyclase prevented the response. Enzyme immunoassays confirmed a linear dose-dependent relationship between SNP and the resulting intracellular cGMP levels (up to 1700 fmol cGMP /oocyte at 14 mM SNP. Results here are the first to show that the efficacy of ion channel activation is decreased by mutations of AQP1 at conserved residues in the C-terminal domain (aspartate D237 and lysine K243. Conclusions These data support the idea that the limited amino acid sequence similarities found between three diverse classes of cGMP-binding proteins are significant to the function of AQP1 as a cGMP-gated ion channel, and provide direct evidence for the involvement of the AQP1 C-terminal domain in cGMP-mediated ion channel activation.

  18. Molecular cloning and biologically active production of IpaD N-terminal region.

    Science.gov (United States)

    Hesaraki, Mahdi; Saadati, Mojtaba; Honari, Hossein; Olad, Gholamreza; Heiat, Mohammad; Malaei, Fatemeh; Ranjbar, Reza

    2013-07-01

    Shigella is known as pathogenic intestinal bacteria in high dispersion and pathogenic bacteria due to invasive plasmid antigen (Ipa). So far, a number of Ipa proteins have been studied to introduce a new candidate vaccine. Here, for the first time, we examined whether the N-terminal region of IpaD(72-162) could be a proper candidate for Shigella vaccine. Initially, the DNA sequence coding N-terminal region was isolated by PCR from Shigella dysenteriae type I and cloned into pET-28a expression vector. Then, the heterologous protein was expressed, optimized and purified by affinity Ni-NTA column. Western blot analysis using, His-tag and IpaD(72-162) polyclonal antibodies, confirmed the purity and specificity of the recombinant protein, respectively. Subsequently, the high immunogenicity of the antigen was shown by ELISA. The results of the sereny test in Guinea pigs showed that IpaD(72-162) provides a protective system against Shigella flexneri 5a and S. dysenteriae type I. Copyright © 2013. Published by Elsevier Ltd.

  19. Effect of N-Terminal Acylation on the Activity of Myostatin Inhibitory Peptides.

    Science.gov (United States)

    Takayama, Kentaro; Nakamura, Akari; Rentier, Cédric; Mino, Yusaku; Asari, Tomo; Saga, Yusuke; Taguchi, Akihiro; Yakushiji, Fumika; Hayashi, Yoshio

    2016-04-19

    Inhibition of myostatin, which negatively regulates skeletal muscle growth, is a promising strategy for the treatment of muscle atrophic disorders, such as muscular dystrophy, cachexia and sarcopenia. Recently, we identified peptide A (H-WRQNTRYSRIEAIKIQILSKLRL-NH2 ), the 23-amino-acid minimum myostatin inhibitory peptide derived from mouse myostatin prodomain, and highlighted the importance of its N-terminal tryptophan residue for the effective inhibition. In this study, we synthesized a series of acylated peptide derivatives focused on the tryptophan residue to develop potent myostatin inhibitors. As a result of the investigation, a more potent derivative of peptide A was successfully identified in which the N-terminal tryptophan residue is replaced with a 2-naphthyloxyacetyl moiety to give an inhibitory peptide three times (1.19±0.11 μm) more potent than parent peptide A (3.53±0.25 μm). This peptide could prove useful as a new starting point for the development of improved inhibitory peptides. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. The EBNA-2 N-Terminal Transactivation Domain Folds into a Dimeric Structure Required for Target Gene Activation.

    Directory of Open Access Journals (Sweden)

    Anders Friberg

    2015-05-01

    Full Text Available Epstein-Barr virus (EBV is a γ-herpesvirus that may cause infectious mononucleosis in young adults. In addition, epidemiological and molecular evidence links EBV to the pathogenesis of lymphoid and epithelial malignancies. EBV has the unique ability to transform resting B cells into permanently proliferating, latently infected lymphoblastoid cell lines. Epstein-Barr virus nuclear antigen 2 (EBNA-2 is a key regulator of viral and cellular gene expression for this transformation process. The N-terminal region of EBNA-2 comprising residues 1-58 appears to mediate multiple molecular functions including self-association and transactivation. However, it remains to be determined if the N-terminus of EBNA-2 directly provides these functions or if these activities merely depend on the dimerization involving the N-terminal domain. To address this issue, we determined the three-dimensional structure of the EBNA-2 N-terminal dimerization (END domain by heteronuclear NMR-spectroscopy. The END domain monomer comprises a small fold of four β-strands and an α-helix which form a parallel dimer by interaction of two β-strands from each protomer. A structure-guided mutational analysis showed that hydrophobic residues in the dimer interface are required for self-association in vitro. Importantly, these interface mutants also displayed severely impaired self-association and transactivation in vivo. Moreover, mutations of solvent-exposed residues or deletion of the α-helix do not impair dimerization but strongly affect the functional activity, suggesting that the EBNA-2 dimer presents a surface that mediates functionally important intra- and/or intermolecular interactions. Our study shows that the END domain is a novel dimerization fold that is essential for functional activity. Since this specific fold is a unique feature of EBNA-2 it might provide a novel target for anti-viral therapeutics.

  1. Acute and chronic effects of a 24-hour intravenous triglyceride emulsion challenge on plasma lecithin : cholesterol acyltransferase, phospholipid transfer protein, and cholesteryl ester transfer protein activities

    NARCIS (Netherlands)

    Riemens, SC; Van Tol, A; Sluiter, WJ; Dullaart, RPF

    Lecithin:cholesterol acyltransferase (LCAT), phospholipid transfer protein (PLTP), and cholesteryl ester transfer protein (CETP) are key factors in remodeling of high density lipoproteins (HDL) and triglyceride-rich lipoproteins. We examined the effect of a large, 24 h intravenous fat load on plasma

  2. Origin of the enhanced performance in poly(3-hexylthiophene) : [6,6]-phenyl C-61-butyric acid methyl ester solar cells upon slow drying of the active layer

    NARCIS (Netherlands)

    Mihailetchi, Valentin D.; Xie, Hangxing; Boer, Bert de; Popescu, Lacramioara M.; Hummelen, Jan C.; Blom, Paul W.M.; Koster, L. Jan Anton

    2006-01-01

    The origin of the enhanced performance of bulk heterojunction solar cells based on slowly dried films of poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl C-61-butyric acid methyl ester is investigated, combining charge transport measurements with numerical device simulations. Slow drying leads to a

  3. Naturally Occurring Cinnamic Acid Sugar Ester Derivatives

    Directory of Open Access Journals (Sweden)

    Yuxin Tian

    2016-10-01

    Full Text Available Cinnamic acid sugar ester derivatives (CASEDs are a class of natural product with one or several phenylacrylic moieties linked with the non-anomeric carbon of a glycosyl skeleton part through ester bonds. Their notable anti-depressant and brains protective activities have made them a topic of great interest over the past several decades. In particular the compound 3′,6-disinapoylsucrose, the index component of Yuanzhi (a well-known Traditional Chinese Medicine or TCM, presents antidepressant effects at a molecular level, and has become a hotspot of research on new lead drug compounds. Several other similar cinnamic acid sugar ester derivatives are reported in traditional medicine as compounds to calm the nerves and display anti-depression and neuroprotective activity. Interestingly, more than one third of CASEDs are distributed in the family Polygalaceae. This overview discusses the isolation of cinnamic acid sugar ester derivatives from plants, together with a systematic discussion of their distribution, chemical structures and properties and pharmacological activities, with the hope of providing references for natural product researchers and draw attention to these interesting compounds.

  4. The N-terminal domain of human DNA helicase Rtel1 contains a redox active iron-sulfur cluster.

    Science.gov (United States)

    Landry, Aaron P; Ding, Huangen

    2014-01-01

    Human telomere length regulator Rtel1 is a superfamily II DNA helicase and is essential for maintaining proper length of telomeres in chromosomes. Here we report that the N-terminal domain of human Rtel1 (RtelN) expressed in Escherichia coli cells produces a protein that contains a redox active iron-sulfur cluster with the redox midpoint potential of -248 ± 10 mV (pH 8.0). The iron-sulfur cluster in RtelN is sensitive to hydrogen peroxide and nitric oxide, indicating that reactive oxygen/nitrogen species may modulate the DNA helicase activity of Rtel1 via modification of its iron-sulfur cluster. Purified RtelN retains a weak binding affinity for the single-stranded (ss) and double-stranded (ds) DNA in vitro. However, modification of the iron-sulfur cluster by hydrogen peroxide or nitric oxide does not significantly affect the DNA binding activity of RtelN, suggesting that the iron-sulfur cluster is not directly involved in the DNA interaction in the N-terminal domain of Rtel1.

  5. The N-Terminal Domain of Human DNA Helicase Rtel1 Contains a Redox Active Iron-Sulfur Cluster

    Directory of Open Access Journals (Sweden)

    Aaron P. Landry

    2014-01-01

    Full Text Available Human telomere length regulator Rtel1 is a superfamily II DNA helicase and is essential for maintaining proper length of telomeres in chromosomes. Here we report that the N-terminal domain of human Rtel1 (RtelN expressed in Escherichia coli cells produces a protein that contains a redox active iron-sulfur cluster with the redox midpoint potential of −248 ± 10 mV (pH 8.0. The iron-sulfur cluster in RtelN is sensitive to hydrogen peroxide and nitric oxide, indicating that reactive oxygen/nitrogen species may modulate the DNA helicase activity of Rtel1 via modification of its iron-sulfur cluster. Purified RtelN retains a weak binding affinity for the single-stranded (ss and double-stranded (ds DNA in vitro. However, modification of the iron-sulfur cluster by hydrogen peroxide or nitric oxide does not significantly affect the DNA binding activity of RtelN, suggesting that the iron-sulfur cluster is not directly involved in the DNA interaction in the N-terminal domain of Rtel1.

  6. The arginine residue within the C-terminal active core of Bombyx mori pheromone biosynthesis-activating neuropeptide (PBAN is essential for receptor binding and activation

    Directory of Open Access Journals (Sweden)

    Takeshi eKawai

    2012-03-01

    Full Text Available In most lepidopteran insects, the biosynthesis of sex pheromones is regulated by pheromone biosynthesis activating neuropeptide (PBAN. Bombyx mori PBAN (BomPBAN consists of 33 amino acid residues and contains a C-terminus FSPRLamide motif as the active core. Among neuropeptides containing the FXPRLamide motif, the arginine (Arg, R residue two positions from the C-terminus is highly conserved across several neuropeptides, which can be designated as RXamide peptides. The purpose of this study was to reveal the role of the Arg residue in the BomPBAN active core. We synthesized a ten-residue peptide corresponding to the C-terminal part of BomPBAN with a series of point mutants at the 2nd position (ie, Arg from the C-terminus, termed the C2 position, and measured their efficacy in stimulating Ca2+ influx in insect cells concomitantly expressing a fluorescent PBAN receptor chimera (PBANR-EGFP and loaded with the fluorescent Ca2+ indicator, Fura Red-AM. PBAN analogs with the C2 position replaced with alanine (Ala, A, aspartic acid (Asp, D, serine (Ser, S or L-2-aminooctanoic acid (Aoc decreased PBAN-like activity. RC2A (SKTRYFSPALamide and RC2D (SKTRYFSPDLamide had the lowest activity and could not inhibit the activity of PBAN C10 (SKTRYFSPRLamide. We also prepared Rhodamine Red-labeled PBAN analogs of the mutants and examined their ability to bind PBANR. In contrast to 100 nM Rhodamine Red-PBAN C10, none of the mutants at the same concentration exhibited PBANR binding. Taken together, our results demonstrate that the C2 Arg residue in BomPBAN is essential for PBANR binding and activation.

  7. Catalytic Oxidation of Allylic Alcohols to Methyl Esters

    DEFF Research Database (Denmark)

    Gallas-Hulin, Agata; Kotni, Rama Krishna; Nielsen, Martin

    2017-01-01

    Aerobic oxidation of allylic alcohols to methyl esters using gold nanoparticles supported on different metal oxide carriers has been performed successfully under mild conditions (room temperature, 0.1 MPa O2) without significant loss of catalytic activity. The effects of different reaction...... parameters are studied to find the suitable reaction conditions. All catalysts are characterised by XRD, XRF and TEM. Among these catalysts, Au/TiO2 showed the most efficient catalytic activity towards the selective oxidation of allylic alcohols to the corresponding esters. Moreover, the same Au/TiO2...... to synthesize methyl esters from allylic alcohols....

  8. Protection against β-amyloid neurotoxicity by a non-toxic endogenous N-terminal β-amyloid fragment and its active hexapeptide core sequence.

    Science.gov (United States)

    Forest, Kelly H; Alfulaij, Naghum; Arora, Komal; Taketa, Ruth; Sherrin, Tessi; Todorovic, Cedomir; Lawrence, James L M; Yoshikawa, Gene T; Ng, Ho-Leung; Hruby, Victor J; Nichols, Robert A

    2018-01-01

    High levels (μM) of beta amyloid (Aβ) oligomers are known to trigger neurotoxic effects, leading to synaptic impairment, behavioral deficits, and apoptotic cell death. The hydrophobic C-terminal domain of Aβ, together with sequences critical for oligomer formation, is essential for this neurotoxicity. However, Aβ at low levels (pM-nM) has been shown to function as a positive neuromodulator and this activity resides in the hydrophilic N-terminal domain of Aβ. An N-terminal Aβ fragment (1-15/16), found in cerebrospinal fluid, was also shown to be a highly active neuromodulator and to reverse Aβ-induced impairments of long-term potentiation. Here, we show the impact of this N-terminal Aβ fragment and a shorter hexapeptide core sequence in the Aβ fragment (Aβcore: 10-15) to protect or reverse Aβ-induced neuronal toxicity, fear memory deficits and apoptotic death. The neuroprotective effects of the N-terminal Aβ fragment and Aβcore on Aβ-induced changes in mitochondrial function, oxidative stress, and apoptotic neuronal death were demonstrated via mitochondrial membrane potential, live reactive oxygen species, DNA fragmentation and cell survival assays using a model neuroblastoma cell line (differentiated NG108-15) and mouse hippocampal neuron cultures. The protective action of the N-terminal Aβ fragment and Aβcore against spatial memory processing deficits in amyloid precursor protein/PSEN1 (5XFAD) mice was demonstrated in contextual fear conditioning. Stabilized derivatives of the N-terminal Aβcore were also shown to be fully protective against Aβ-triggered oxidative stress. Together, these findings indicate an endogenous neuroprotective role for the N-terminal Aβ fragment, while active stabilized N-terminal Aβcore derivatives offer the potential for therapeutic application. © 2017 International Society for Neurochemistry.

  9. Apomorphine and its esters

    DEFF Research Database (Denmark)

    Borkar, Nrupa; Chen, Zhizhong; Saaby, Lasse

    2016-01-01

    Oral delivery of apomorphine via prodrug principle may be a potential treatment for Parkinson's disease. The purpose of this study was to investigate the transport and stability of apomorphine and its esters across Caco-2 cell monolayer and their affinity towards chylomicrons. Apomorphine......, monolauroyl apomorphine (MLA) and dilauroyl apomorphine (DLA) were subjected to apical to basolateral (A-B) and basolateral to apical (B-A) transport across Caco-2 cell monolayer. The stability of these compounds was also assessed by incubation at intestinal pH and physiological pH with and without Caco-2...

  10. Conversion of functionally undefined homopentameric protein PbaA into a proteasome activator by mutational modification of its C-terminal segment conformation.

    Science.gov (United States)

    Yagi-Utsumi, Maho; Sikdar, Arunima; Kozai, Toshiya; Inoue, Rintaro; Sugiyama, Masaaki; Uchihashi, Takayuki; Yagi, Hirokazu; Satoh, Tadashi; Kato, Koichi

    2018-01-01

    Recent bioinformatic analyses identified proteasome assembly chaperone-like proteins, PbaA and PbaB, in archaea. PbaB forms a homotetramer and functions as a proteasome activator, whereas PbaA does not interact with the proteasome despite the presence of an apparent C-terminal proteasome activation motif. We revealed that PbaA forms a homopentamer predominantly in the closed conformation with its C-terminal segments packed against the core domains, in contrast to the PbaB homotetramer with projecting C-terminal segments. This prompted us to create a novel proteasome activator based on a well-characterized structural framework. We constructed a panel of chimeric proteins comprising the homopentameric scaffold of PbaA and C-terminal segment of PbaB and subjected them to proteasome-activating assays as well as small-angle X-ray scattering and high-speed atomic force microscopy. The results indicated that the open conformation and consequent proteasome activation activity could be enhanced by replacement of the crystallographically disordered C-terminal segment of PbaA with the corresponding disordered segment of PbaB. Moreover, these effects can be produced just by incorporating two glutamate residues into the disordered C-terminal segment of PbaA, probably due to electrostatic repulsion among the negatively charged segments. Thus, we successfully endowed a functionally undefined protein with proteasome-activating activity by modifying its C-terminal segment. © The Author(s) 2017. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  11. Amino-terminal residues of ΔNp63, mutated in ectodermal dysplasia, are required for its transcriptional activity.

    Science.gov (United States)

    Lena, Anna Maria; Duca, Sara; Novelli, Flavia; Melino, Sonia; Annicchiarico-Petruzzelli, Margherita; Melino, Gerry; Candi, Eleonora

    2015-11-13

    p63, a member of the p53 family, is a crucial transcription factor for epithelial development and skin homeostasis. Heterozygous mutations in TP63 gene have been associated with human ectodermal dysplasia disorders. Most of these TP63 mutations are missense mutations causing amino acidic substitutions at p63 DNA binding or SAM domains that reduce or abolish the transcriptional activity of mutants p63. A significant number of mutants, however, resides in part of the p63 protein that apparently do not affect DNA binding and/or transcriptional activity, such as the N-terminal domain. Here, we characterize five p63 mutations at the 5' end of TP63 gene aiming to understand the pathogenesis of the diseases and to uncover the role of ΔNp63α N-terminus residues in determining its transactivation potential. Copyright © 2015 Elsevier Inc. All rights reserved.

  12. Discovery and analysis of an active long terminal repeat-retrotransposable element in Aspergillus oryzae.

    Science.gov (United States)

    Jie Jin, Feng; Hara, Seiichi; Sato, Atsushi; Koyama, Yasuji

    2014-01-01

    Wild-type Aspergillus oryzae RIB40 contains two copies of the AO090005001597 gene. We previously constructed A. oryzae RIB40 strain, RKuAF8B, with multiple chromosomal deletions, in which the AO090005001597 copy number was found to be increased significantly. Sequence analysis indicated that AO090005001597 is part of a putative 6,000-bp retrotransposable element, flanked by two long terminal repeats (LTRs) of 669 bp, with characteristics of retroviruses and retrotransposons, and thus designated AoLTR (A. oryzae LTR-retrotransposable element). AoLTR comprised putative reverse transcriptase, RNase H, and integrase domains. The deduced amino acid sequence alignment of AoLTR showed 94% overall identity with AFLAV, an A. flavus Tf1/sushi retrotransposon. Quantitative real-time RT-PCR showed that AoLTR gene expression was significantly increased in the RKuAF8B, in accordance with the increased copy number. Inverse PCR indicated that the full-length retrotransposable element was randomly integrated into multiple genomic locations. However, no obvious phenotypic changes were associated with the increased AoLTR gene copy number.

  13. Esters with water esters 2-c to 6-c

    CERN Document Server

    Getzen, F W; Hefter, G T; Maczynski, Andrzej

    1992-01-01

    This volume is the first of two devoted to esters and water. It includes solubility data for binary systems containing an ester and water up to the end of 1988. The critical evaluations were all prepared by one author and an introductory section has been included to elaborate the philosophy and methodology followed in the evaluations.

  14. Cross-Aldol Reaction of Activated Carbonyls with Nitrosocarbonyl Intermediates: Stereoselective Synthesis toward α-Hydroxy-β-amino Esters and Amides.

    Science.gov (United States)

    Mallik, Sumitava; Bhajammanavar, Vinod; Ramakrishna, Isai; Baidya, Mahiuddin

    2017-07-21

    A practical and flexible strategy toward α-hydroxy-β-amino esters and amides, which are important biological motifs, based on an organocatalytic cross-aldol reaction of in situ-generated nitrosocarbonyl intermediates followed by hydrogenation is presented. The protocol features operational simplicity, high yields, a wide substrate scope, and high regio- and diastereoselectivity profiles. The utility of this method was showcased through the synthesis of bestatin analogues and indole formation.

  15. International conference on lessons learned from the decommissioning of nuclear facilities and the safe termination of nuclear activities. Contributed papers

    International Nuclear Information System (INIS)

    2006-12-01

    The International Atomic Energy Agency (IAEA), in cooperation with the European Commission (EC), Nuclear Energy Agency to the Organisation for Economic Co-operation and Development (OECD/NEA), and the World Nuclear Association (WNA), organized an International Conference on Lessons Learned from the Decommissioning of Nuclear Facilities and the Safe Termination of Nuclear Activities from 11 to 15 December 2006 in Athens, Greece. This Book of Contributed Papers contains technical papers and posters contributed by experts from operating organisations, regulatory bodies, technical support organisations, and other institutions on issues falling within the scope of the Conference. The following main topics were covered: Evolution of national and international policies and criteria for the safe and efficient decommissioning of nuclear facilities and safe termination of nuclear activities; Review of lessons learned from ongoing or completed activities associated with decommissioning; Improvement of safety and efficiency through the use of new and innovative technologies; Practical aspects in the management of material, waste and sites resulting from decommissioning, including the management of waste in the absence of repositories and waste acceptance requirements; Procedures for demonstrating compliance with clearance criteria; Experience from radiological assessments associated with decommissioning; Involvement of the local communities and the impact that decommissioning activities has on them. The presented papers and posters were reviewed and accepted following the guidelines established by the Conference Programme Committee for consideration at the Conference. The material compiled in this Book of Contributed Papers has not undergone rigorous editing by the editorial staff of the IAEA. However, certain modifications were made: a unified format was adopted for all papers; and minor corrections were made in the text where required. Each paper and poster has been indexed

  16. International conference on lessons learned from the decommissioning of nuclear facilities and the safe termination of nuclear activities. Contributed papers

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-12-15

    The International Atomic Energy Agency (IAEA), in cooperation with the European Commission (EC), Nuclear Energy Agency to the Organisation for Economic Co-operation and Development (OECD/NEA), and the World Nuclear Association (WNA), organized an International Conference on Lessons Learned from the Decommissioning of Nuclear Facilities and the Safe Termination of Nuclear Activities from 11 to 15 December 2006 in Athens, Greece. This Book of Contributed Papers contains technical papers and posters contributed by experts from operating organisations, regulatory bodies, technical support organisations, and other institutions on issues falling within the scope of the Conference. The following main topics were covered: Evolution of national and international policies and criteria for the safe and efficient decommissioning of nuclear facilities and safe termination of nuclear activities; Review of lessons learned from ongoing or completed activities associated with decommissioning; Improvement of safety and efficiency through the use of new and innovative technologies; Practical aspects in the management of material, waste and sites resulting from decommissioning, including the management of waste in the absence of repositories and waste acceptance requirements; Procedures for demonstrating compliance with clearance criteria; Experience from radiological assessments associated with decommissioning; Involvement of the local communities and the impact that decommissioning activities has on them. The presented papers and posters were reviewed and accepted following the guidelines established by the Conference Programme Committee for consideration at the Conference. The material compiled in this Book of Contributed Papers has not undergone rigorous editing by the editorial staff of the IAEA. However, certain modifications were made: a unified format was adopted for all papers; and minor corrections were made in the text where required. Each paper and poster has been indexed

  17. Synthesis and Evaluation of the Antioxidant Activity of Lipophilic Phenethyl Trifluoroacetate Esters by In Vitro ABTS, DPPH and in Cell-Culture DCF Assays

    Directory of Open Access Journals (Sweden)

    Roberta Bernini

    2018-01-01

    Full Text Available Polyphenols are natural compounds showing a variety of health-promoting effects. Unfortunately, due to low lipid solubility, their applications in the pharmaceutical, food, and cosmetic industries are limited. With the aim of obtaining novel lipophilic derivatives, the present study reports the synthesis of a series of phenethyl trifluoroacetate esters containing up to two hydroxyl groups in the aromatic ring. Experimental logP values confirmed a greater lipophilicity of the novel compounds compared to the parent compounds. The radical scavenging capacity of all phenethyl trifluoroacetate esters was evaluated by in vitro assays (ABTS, DPPH and in cultured cells (L6 myoblasts and THP-1 leukemic monocytes using 2′,7′-dichlorodihydrofluorescein diacetate. These data revealed that the esters showed a good antioxidant effect that was strictly dependent on the grade of hydroxylation of the phenyl ring. The lack of toxicity, evaluated by the MTT assay and proliferation curves, makes these trifluoroacetates attractive derivatives for pharmaceutical, food, and cosmetic applications.

  18. Compartmentalized beta subunit distribution determines characteristics and ethanol sensitivity of somatic, dendritic, and terminal large-conductance calcium-activated potassium channels in the rat central nervous system.

    Science.gov (United States)

    Wynne, P M; Puig, S I; Martin, G E; Treistman, S N

    2009-06-01

    Neurons are highly differentiated and polarized cells, whose various functions depend upon the compartmentalization of ion channels. The rat hypothalamic-neurohypophysial system (HNS), in which cell bodies and dendrites reside in the hypothalamus, physically separated from their nerve terminals in the neurohypophysis, provides a particularly powerful preparation in which to study the distribution and regional properties of ion channel proteins. Using electrophysiological and immunohistochemical techniques, we characterized the large-conductance calcium-activated potassium (BK) channel in each of the three primary compartments (soma, dendrite, and terminal) of HNS neurons. We found that dendritic BK channels, in common with somatic channels but in contrast to nerve terminal channels, are insensitive to iberiotoxin. Furthermore, analysis of dendritic BK channel gating kinetics indicates that they, like somatic channels, have fast activation kinetics, in contrast to the slow gating of terminal channels. Dendritic and somatic channels are also more sensitive to calcium and have a greater conductance than terminal channels. Finally, although terminal BK channels are highly potentiated by ethanol, somatic and dendritic channels are insensitive to the drug. The biophysical and pharmacological properties of somatic and dendritic versus nerve terminal channels are consistent with the characteristics of exogenously expressed alphabeta1 versus alphabeta4 channels, respectively. Therefore, one possible explanation for our findings is a selective distribution of auxiliary beta1 subunits to the somatic and dendritic compartments and beta4 to the terminal compartment. This hypothesis is supported immunohistochemically by the appearance of distinct punctate beta1 or beta4 channel clusters in the membrane of somatic and dendritic or nerve terminal compartments, respectively.

  19. Structure of long terminal repeats of transcriptionally active and inactive copies of Drosophila mobile dispersed genetic elements mdg3

    International Nuclear Information System (INIS)

    Dzhumagaliev, E.B.; Mazo, A.N.; Baev, A.A. Jr.; Gorelova, T.V.; Arkhipova, I.R.; Shuppe, N.G.; Il'in, Yu.V.

    1986-01-01

    The authors have determined the nucleotide sequences of long terminal repeats (LTRS) and adjacent regions in the transcribed and nontranscribed variants of the mobile dispersed gene mdg3. In its main characteristics the mdg3 is similar to other mdg. Its integration into chromosomal DNA brings about duplication of the 4 bp of the host DNA, no specificity of the mdg integration at the nucleotide level being detected. The mdg3 is flanked by a 5 bp inverted repeat. The variations in the length of the LTR in different mdg copies is mainly due to duplication of certain sequences in the U3 and R regions. mdg3 copies with a LTR length of 267 bp are the most abundant and are completely conservative in their primary structure. They are transcribed in the cells of the 67J25D culture, but not transcribed in the K/sub c/ line, where another mdg3 variant with a LTR length of 293 bp is transcriptionally active. The SI mapping of transcription initiation and termination sites has shown that in both mdg3 variants they are localized in the same LTR regions, and that the LTR itself has a characteristic U3-R-U5 structure-like retroviral LTRs. The possible factors involved in the regulation of mdg transcription are discussed

  20. The C-terminal sequence of IFITM1 regulates its anti-HIV-1 activity.

    Directory of Open Access Journals (Sweden)

    Rui Jia

    Full Text Available The interferon-inducible transmembrane (IFITM proteins inhibit a wide range of viruses. We previously reported the inhibition of human immunodeficiency virus type 1 (HIV-1 strain BH10 by human IFITM1, 2 and 3. It is unknown whether other HIV-1 strains are similarly inhibited by IFITMs and whether there exists viral countermeasure to overcome IFITM inhibition. We report here that the HIV-1 NL4-3 strain (HIV-1NL4-3 is not restricted by IFITM1 and its viral envelope glycoprotein is partly responsible for this insensitivity. However, HIV-1NL4-3 is profoundly inhibited by an IFITM1 mutant, known as Δ(117-125, which is deleted of 9 amino acids at the C-terminus. In contrast to the wild type IFITM1, which does not affect HIV-1 entry, the Δ(117-125 mutant diminishes HIV-1NL4-3 entry by 3-fold. This inhibition correlates with the predominant localization of Δ(117-125 to the plasma membrane where HIV-1 entry occurs. In spite of strong conservation of IFITM1 among most species, mouse IFITM1 is 19 amino acids shorter at its C-terminus as compared to human IFITM1 and, like the human IFITM1 mutant Δ(117-125, mouse IFITM1 also inhibits HIV-1 entry. This is the first report illustrating the role of viral envelope protein in overcoming IFITM1 restriction. The results also demonstrate the importance of the C-terminal region of IFITM1 in modulating the antiviral function through controlling protein subcellular localization.

  1. Impairment of GABA transporter GAT-1 terminates cortical recurrent network activity via enhanced phasic inhibition

    Directory of Open Access Journals (Sweden)

    Daniel Simon Razik

    2013-09-01

    Full Text Available In the central nervous system, GABA transporters (GATs very efficiently clear synaptically released GABA from the extracellular space, and thus exert a tight control on GABAergic inhibition. In neocortex, GABAergic inhibition is heavily recruited during recurrent phases of spontaneous action potential activity which alternate with neuronally quiet periods. Therefore, such activity should be quite sensitive to minute alterations of GAT function. Here, we explored the effects of a gradual impairment of GAT-1 and GAT-2/3 on spontaneous recurrent network activity – termed network bursts and silent periods – in organotypic slice cultures of rat neocortex. The GAT-1 specific antagonist NO-711 depressed activity already at nanomolar concentrations (IC50 for depression of spontaneous multiunit firing rate of 42 nM, reaching a level of 80% at 500-1000 nM. By contrast, the GAT-2/3 preferring antagonist SNAP-5114 had weaker and less consistent effects. Several lines of evidence pointed towards an enhancement of phasic GABAergic inhibition as the dominant activity-depressing mechanism: network bursts were drastically shortened, phasic GABAergic currents decayed slower, and neuronal excitability during ongoing activity was diminished. In silent periods, NO-711 had little effect on neuronal excitability or membrane resistance, quite in contrast to the effects of muscimol, a GABA mimetic which activates GABAA receptors tonically. Our results suggest that an enhancement of phasic GABAergic inhibition efficiently curtails cortical recurrent activity and may mediate antiepileptic effects of therapeutically relevant concentrations of GAT-1 antagonists.

  2. Sugar ester surfactants: enzymatic synthesis and applications in food industry.

    Science.gov (United States)

    Neta, Nair S; Teixeira, José A; Rodrigues, Lígia R

    2015-01-01

    Sugar esters are non-ionic surfactants that can be synthesized in a single enzymatic reaction step using lipases. The stability and efficiency of lipases under unusual conditions and using non-conventional media can be significantly improved through immobilization and protein engineering. Also, the development of de novo enzymes has seen a significant increase lately under the scope of the new field of synthetic biology. Depending on the esterification degree and the nature of fatty acid and/or sugar, a range of sugar esters can be synthesized. Due to their surface activity and emulsifying capacity, sugar esters are promising for applications in food industry.

  3. Synthetic Methods for Ester Bond Formation and Conformational Analysis of Ester-Containing Carbohydrates

    Science.gov (United States)

    Hackbusch, Sven

    This dissertation encompasses work related to synthetic methods for the formation of ester linkages in organic compounds, as well as the investigation of the conformational influence of the ester functional group on the flexibility of inter-saccharide linkages, specifically, and the solution phase structure of ester-containing carbohydrate derivatives, in general. Stereoselective reactions are an important part of the field of asymmetric synthesis and an understanding of their underlying mechanistic principles is essential for rational method development. Here, the exploration of a diastereoselective O-acylation reaction on a trans-2-substituted cyclohexanol scaffold is presented, along with possible reasons for the observed reversal of stereoselectivity dependent on the presence or absence of an achiral amine catalyst. In particular, this work establishes a structure-activity relationship with regard to the trans-2-substituent and its role as a chiral auxiliary in the reversal of diastereoselectivity. In the second part, the synthesis of various ester-linked carbohydrate derivatives, and their conformational analysis is presented. Using multidimensional NMR experiments and computational methods, the compounds' solution-phase structures were established and the effect of the ester functional group on the molecules' flexibility and three-dimensional (3D) structure was investigated and compared to ether or glycosidic linkages. To aid in this, a novel Karplus equation for the C(sp2)OCH angle in ester-linked carbohydrates was developed on the basis of a model ester-linked carbohydrate. This equation describes the sinusoidal relationship between the C(sp2)OCH dihedral angle and the corresponding 3JCH coupling constant that can be determined from a J-HMBC NMR experiment. The insights from this research will be useful in describing the 3D structure of naturally occurring and lab-made ester-linked derivatives of carbohydrates, as well as guiding the de novo-design of

  4. Do polar faculae terminate or commence an extended cycle of solar activity?

    International Nuclear Information System (INIS)

    Bumba, V.

    1990-01-01

    From the local as well as from the global points of view, polar magnetic fields are formed from successively developed trailing polarity fields expelled from the main activity zone. Polar faculae observed during the 20th and the 21st cycles of activity fill in the areas covered by the most intense unipolar fields distributed in the convection network. These polar regions formed from magnetic fields of an old activity cycle are sharply separated from low-latitude magnetic fields and from fields developed by a new cycle of activity. The polarity distribution in polar faculae seems to follow from unipolarity of their magnetic fields - the prevailing polarity becomes the main leading polarity. The greatest part of the main activity zone, the most intense faculae shifting equatorwards are connected with the zone of the prevailing leading polarity magnetic fields. Some of these faculae - the weak and inhomogeneously distributed ones, bordering the main faculae butterflies polewards - are related again to the trailing polarity fields shifting polewards. The main characteristic of the latitudinal distribution of solar faculae is the existence of their two latitudinal types: the polar faculae shifting polewards are related to the trailing polarity fields of the old cycle, the faculae of the main activity zone shifting equatorwards are related mainly (from the global point of view) to the leading polarity fields, and their activity ends several years earlier than that of the polar ones. The polar faculae with their magnetic fields represent the last phase of the magnetic activity cycle lasting 15-17 years. (author). 6 figs., 21 refs

  5. Antecedents of Customer Relationship Termination

    DEFF Research Database (Denmark)

    Geersbro, Jens; Ritter, Thomas

    To end business relationships, or to more actively terminate relationships, has long been acknowledged as part of customer relationship management. However, compared to other elements such as initiation and maintenance of relationships, little is known about the termination of business...... relationships as a managerial task. This paper contributes by (1) developing a conceptualization of relationship termination competence and (2) analyzing its antecedents. The empirical results identify termination acceptance, definition non-customers, organizational relationship termination routines......, and motivation as significant antecedents. Because of this, managers need to develop their organizations in order to use relationship termination as a vital strategy....

  6. Distal loop flexibility of a regulatory domain modulates dynamics and activity of C-terminal SRC kinase (csk.

    Directory of Open Access Journals (Sweden)

    Sulyman Barkho

    Full Text Available The Src family of tyrosine kinases (SFKs regulate numerous aspects of cell growth and differentiation and are under the principal control of the C-terminal Src Kinase (Csk. Csk and SFKs share a modular design with the kinase domain downstream of the N-terminal SH2 and SH3 domains that regulate catalytic function and membrane localization. While the function of interfacial segments in these multidomain kinases are well-investigated, little is known about how surface sites and long-range, allosteric coupling control protein dynamics and catalytic function. The SH2 domain of Csk is an essential component for the down-regulation of all SFKs. A unique feature of the SH2 domain of Csk is the tight turn in place of the canonical CD loop in a surface site far removed from kinase domain interactions. In this study, we used a combination of experimental and computational methods to probe the importance of this difference by constructing a Csk variant with a longer SH2 CD loop to mimic the flexibility found in homologous kinase SH2 domains. Our results indicate that while the fold and function of the isolated domain and the full-length kinase are not affected by loop elongation, native protein dynamics that are essential for efficient catalysis are perturbed. We also identify key motifs and routes through which the distal SH2 site might influence catalysis at the active site. This study underscores the sensitivity of intramolecular signaling and catalysis to native protein dynamics that arise from modest changes in allosteric regions while providing a potential strategy to alter intrinsic activity and signaling modulation.

  7. Female Choice Reveals Terminal Investment in Male Mealworm Beetles, Tenebrio molitor, after a Repeated Activation of the Immune System

    Science.gov (United States)

    Krams, I; Daukšte, J; Kivleniece, I; Krama, T; Rantala, MJ; Ramey, G; Šauša, L

    2011-01-01

    Increasing evidence suggests that secondary sexual traits reflect immunocompetence of males in many animal species. This study experimentally investigated whether a parasite-like immunological challenge via a nylon implant affects sexual attractiveness of males in Tenebrio molitor L. (Coleoptera: Tenebrionidae) Although a single immunological challenge significantly reduced sexual attractiveness and locomotor activity of males, it had no adverse effect on their survival. A second immune challenge of the same males increased their attractiveness. However, it was found that the repeated challenge significantly reduced locomotor activity of males and caused higher mortality. This result indicates terminal investment on sexual signaling, which is supposedly based on a trade-off between pheromone production and energy expenditures needed for such activities as recovery of immune system and locomotor activity. When the third implantation was carried out in the same group of males, melanization of nylon implants was found to be lower in more attractive than in less attractive males. This suggests that males that became sexually attractive after the second immune challenge did not invest in recovery of their immune system. PMID:21864151

  8. Inhibition of small-conductance Ca2+-activated K+ channels terminates and protects against atrial fibrillation

    DEFF Research Database (Denmark)

    Diness, Jonas Goldin; Sørensen, Ulrik S; Nissen, Jakob Dahl

    2010-01-01

    Recently, evidence has emerged that small-conductance Ca(2+)-activated K(+) (SK) channels are predominantly expressed in the atria in a number of species including human. In rat, guinea pig, and rabbit ex vivo and in vivo models of atrial fibrillation (AF), we used 3 different SK channel inhibito...

  9. The human receptor for urokinase plasminogen activator. NH2-terminal amino acid sequence and glycosylation variants

    DEFF Research Database (Denmark)

    Behrendt, N; Rønne, E; Ploug, M

    1990-01-01

    The receptor for human urokinase-type plasminogen activator (u-PA) was purified from phorbol 12-myristate 13-acetate-stimulated U937 cells by temperature-induced phase separation of detergent extracts, followed by affinity chromatography with immobilized diisopropyl fluorophosphate-treated u...

  10. Autocatalytic activity and substrate specificity of the pestivirus N-terminal protease Npro.

    Science.gov (United States)

    Gottipati, Keerthi; Acholi, Sudheer; Ruggli, Nicolas; Choi, Kyung H

    2014-03-01

    Pestivirus N(pro) is the first protein translated in the viral polypeptide, and cleaves itself off co-translationally generating the N-terminus of the core protein. Once released, N(pro) blocks the host׳s interferon response by inducing degradation of interferon regulatory factor-3. N(pro׳)s intracellular autocatalytic activity and lack of trans-activity have hampered in vitro cleavage studies to establish its substrate specificity and the roles of individual residues. We constructed N(pro)-GFP fusion proteins that carry the authentic cleavage site and determined the autoproteolytic activities of N(pro) proteins containing substitutions at the predicted catalytic sites Glu22 and Cys69, at Arg100 that forms a salt bridge with Glu22, and at the cleavage site Cys168. Contrary to previous reports, we show that N(pro׳)s catalytic activity does not involve Glu22, which may instead be involved in protein stability. Furthermore, N(pro) does not have specificity for Cys168 at the cleavage site even though this residue is conserved throughout the pestivirus genus. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. Cytosolic cholesterol ester hydrolase in adrenal cortex

    OpenAIRE

    Tocher, Douglas R.

    1983-01-01

    Cholesterol ester hydrolase (CEH) in adrenocortical cytosol was known to be phosphorylated and activated, in response to ACTH in a cAMPdependent protein kinase mediated process. The purification of CEH from bovine adrenocortical cytosol was attempted. The use of detergents to solubilise the enzyme from lipid-rich aggregates was investigated and sodium cholate was found to be effective. A purification procedure using cholate solubilised enzyme was developed. The detergent int...

  12. Tandem Carbocupration/Oxygenation of Terminal Alkynes

    Science.gov (United States)

    Zhang, Donghui; Ready, Joseph M.

    2008-01-01

    A direct and general synthesis of α-branched aldehydes and their enol derivatives is described. Carbocupration of terminal alkynes and subsequent oxygenation with lithium tert-butyl peroxide generates a metallo-enolate. Trapping with various electrophiles provides α-branched aldehydes or stereo-defined trisubstituted enol esters or silyl ethers. The tandem carbocupration/oxygenation tolerates alkyl and silyl ethers, esters and tertiary amines. The reaction is effective with organocopper complexes derived from primary, secondary and tertiary Grignard reagents and from n-butyllithium. PMID:16321021

  13. Ubiquitin carboxyl terminal hydrolase L1 negatively regulates TNFα-mediated vascular smooth muscle cell proliferation via suppressing ERK activation

    International Nuclear Information System (INIS)

    Ichikawa, Tomonaga; Li, Jinqing; Dong, Xiaoyu; Potts, Jay D.; Tang, Dong-Qi; Li, Dong-Sheng; Cui, Taixing

    2010-01-01

    Deubiquitinating enzymes (DUBs) appear to be critical regulators of a multitude of processes such as proliferation, apoptosis, differentiation, and inflammation. We have recently demonstrated that a DUB of ubiquitin carboxyl terminal hydrolase L1 (UCH-L1) inhibits vascular lesion formation via suppressing inflammatory responses in vasculature. However, the precise underlying mechanism remains to be defined. Herein, we report that a posttranscriptional up-regulation of UCH-L1 provides a negative feedback to tumor necrosis factor alpha (TNFα)-mediated activation of extracellular signal-regulated kinases (ERK) and proliferation in vascular smooth muscle cells (VSMCs). In rat adult VSMCs, adenoviral over-expression of UCH-L1 inhibited TNFα-induced activation of ERK and DNA synthesis. In contrast, over-expression of UCH-L1 did not affect platelet derived growth factor (PDGF)-induced VSMC proliferation and activation of growth stimulating cascades including ERK. TNFα hardly altered UCH-L1 mRNA expression and stability; however, up-regulated UCH-L1 protein expression via increasing UCH-L1 translation. These results uncover a novel mechanism by which UCH-L1 suppresses vascular inflammation.

  14. A novel disulfide bond in the SH2 Domain of the C-terminal Src kinase controls catalytic activity.

    Science.gov (United States)

    Mills, Jamie E; Whitford, Paul C; Shaffer, Jennifer; Onuchic, Jose N; Adams, Joseph A; Jennings, Patricia A

    2007-02-02

    The SH2 domain of the C-terminal Src kinase [Csk] contains a unique disulfide bond that is not present in other known SH2 domains. To investigate whether this unusual disulfide bond serves a novel function, the effects of disulfide bond formation on catalytic activity of the full-length protein and on the structure of the SH2 domain were investigated. The kinase activity of full-length Csk decreases by an order of magnitude upon formation of the disulfide bond in the distal SH2 domain. NMR spectra of the fully oxidized and fully reduced SH2 domains exhibit similar chemical shift patterns and are indicative of similar, well-defined tertiary structures. The solvent-accessible disulfide bond in the isolated SH2 domain is highly stable and far from the small lobe of the kinase domain. However, reduction of this bond results in chemical shift changes of resonances that map to a cluster of residues that extend from the disulfide bond across the molecule to a surface that is in direct contact with the small lobe of the kinase domain in the intact molecule. Normal mode analyses and molecular dynamics calculations suggest that disulfide bond formation has large effects on residues within the kinase domain, most notably within the active-site cleft. Overall, the data indicate that reversible cross-linking of two cysteine residues in the SH2 domain greatly impacts catalytic function and interdomain communication in Csk.

  15. Antimicrobial Activity of Human Prion Protein Is Mediated by Its N-Terminal Region

    OpenAIRE

    Pasupuleti, Mukesh; Roupe, Markus; Rydeng?rd, Victoria; Surewicz, Krystyna; Surewicz, Witold K.; Chalupka, Anna; Malmsten, Martin; S?rensen, Ole E.; Schmidtchen, Artur

    2009-01-01

    BACKGROUND: Cellular prion-related protein (PrP(c)) is a cell-surface protein that is ubiquitously expressed in the human body. The multifunctionality of PrP(c), and presence of an exposed cationic and heparin-binding N-terminus, a feature characterizing many antimicrobial peptides, made us hypothesize that PrP(c) could exert antimicrobial activity. METHODOLOGY AND PRINCIPAL FINDINGS: Intact recombinant PrP exerted antibacterial and antifungal effects at normal and low pH. Studies employing r...

  16. Business process modeling of industrial maintenance at TRANSPETRO: integrating oil pipeline and marine terminals activities

    Energy Technology Data Exchange (ETDEWEB)

    Arruda, Daniela Mendonca; Oliveira, Italo Luiz [TRANSPETRO - PETROBRAS Transporte S.A., Rio de Janeiro, RJ (Brazil). Diretoria de Terminais e Oleodutos; Almeida, Maria Fatima Ludovico de [Pontificia Universidade Catolica do Rio de Janeiro (PUC-Rio), Rio de Janeiro, RJ (Brazil). Programa de Pos-Graduacao em Metrologia para Qualidade e Inovacao

    2009-07-01

    This paper describes the experience of TRANSPETRO in remodeling industrial maintenance activities focusing on: preparing for business process modeling (BPM); mapping and analyzing 'As-Is' process; designing 'To-Be' process; implementing remodeled process; improving process continuously. The conceptual model and results achieved will contribute to several areas within the company as: reliability engineering; human resources, including employees' selective processes, training and development, and certifications; standardization process encompassing standard and operational procedures adoption according to up-dating external normative references and legal requirements; health, safety and environment (HSE) performance improvement. These are some of potential benefits from BPM focusing on TRANSPETRO's industrial maintenance area in the search of operational excellence. (author)

  17. Kinetic Study of the Aroxyl-Radical-Scavenging Activity of Five Fatty Acid Esters and Six Carotenoids in Toluene Solution: Structure-Activity Relationship for the Hydrogen Abstraction Reaction.

    Science.gov (United States)

    Mukai, Kazuo; Yoshimoto, Maya; Ishikura, Masaharu; Nagaoka, Shin-Ichi

    2017-08-17

    A kinetic study of the reaction between an aroxyl radical (ArO • ) and fatty acid esters (LHs 1-5, ethyl stearate 1, ethyl oleate 2, ethyl linoleate 3, ethyl linolenate 4, and ethyl arachidonate 5) has been undertaken. The second-order rate constants (k s ) for the reaction of ArO • with LHs 1-5 in toluene at 25.0 °C have been determined spectrophotometrically. The k s values obtained increased in the order of LH 1 LHs 1-5. The k s value for LH 5 was 2.93 × 10 -3 M -1 s -1 . From the result, it has been clarified that the reaction of ArO • with LHs 1-5 was explained by an allylic hydrogen abstraction reaction. A similar kinetic study was performed for the reaction of ArO • with six carotenoids (Car-Hs 1-6, astaxanthin 1, β-carotene 2, lycopene 3, capsanthin 4, zeaxanthin 5, and lutein 6). The k s values obtained increased in the order of Car-H 1 LHs 1-5. The results of detailed analyses of the k s values for the above reaction indicated that the reaction was also explained by an allylic hydrogen abstraction reaction. Furthermore, the structure-activity relationship for the reaction was discussed by taking the result of density functional theory calculation reported by Martinez and Barbosa into account.

  18. Enzymatic synthesizing of phytosterol oleic esters.

    Science.gov (United States)

    Pan, Xinxin; Chen, Biqiang; Wang, Juan; Zhang, Xinzhi; Zhul, Biyun; Tan, Tianwei

    2012-09-01

    A method of synthesizing the phytosterol esters from oleic acid and sterols was studied, using immobilized lipase Candida sp. 99-125 as catalyst. Molar ratio (oleic acid/phytosterols), temperature, reaction period, organic solvents, catalyst, and silica-gel drier were optimized, and the result showed that 93.4% of the sterols had been esterified under the optimal synthetic condition: the molar ratio of oleic acid/phytosterol is 1:1 in 10 mL iso-octane, immobilized lipase (w, 140% of the sterols), incubated in an orbital shaker (200 rpm) at a temperature of 45 °C for 24 h. The immobilized lipase could be reused for at least 13 times with limited loss of esterification activity. The conversion still maintained up to 86.6%. Hence, this developed process for synthesizing phytosterol esters could be considered as simple and low-energy consumption compared to existing chemical processes.

  19. Baker's yeast: production of D- and L-3-hydroxy esters

    DEFF Research Database (Denmark)

    Dahl, Allan Carsten; Madsen, Jørgen Øgaard

    1998-01-01

    harvested while growing. In contrast, the stereoselectivity was shifted towards L-hydroxy esters when the oxo esters were added slowly to ordinary baker's yeast supplied with gluconolactone as co-substrate. The reduction rate with gluconolactone was increased by active aeration. Ethyl L-(S)-3......Baker's yeast grown under oxygen limited conditions and used in the reduction of 3-oxo esters results in a shift of the stereoselectivity of the yeast towards D-hydroxy esters as compared with ordinary baker's yeast. The highest degree of stereoselectivity was obtained with growing yeast or yeast......-hydroxybutanoate was afforded in >99% ee. Both enantiomers of ethyl 3-hydroxypentanoate, D-(R) in 96% ee and L-(S) in 93% ee, and of ethyl 4-chloro-3-hydroxybutanoate, D-(S) in 98% ee and L-(R) in 94% ee, were obtained. The results demonstrate that the stereoselectivity of baker's yeast can be controlled...

  20. α-Imino Esters in Organic Synthesis: Recent Advances.

    Science.gov (United States)

    Eftekhari-Sis, Bagher; Zirak, Maryam

    2017-06-28

    α-Imino esters are useful precursors for the synthesis of a variety of types of natural and unnatural α-amino acid derivatives, with a wide range of biological activities. Due to the adjacent ester group, α-imino esters are more reactive relative to other types of imines and undergo different kinds of reactions, including organometallics addition, metal catalyzed vinylation and alkynylation, aza-Henry, aza-Morita-Baylis-Hillman, imino-ene, Mannich-type, and cycloaddition reactions, as well as hydrogenation and reduction. This review discusses the mechanism, scope, and applications of the reactions of α-imino esters and related compounds in organic synthesis, covering the literature from the last 12 years.

  1. Saliva-catalyzed hydrolysis of a ketobemidone ester prodrug

    DEFF Research Database (Denmark)

    Hansen, L.B.; Christrup, Lona Louring; Bundgaard, H.

    1992-01-01

    Saliva enzyme-catalysed hydrolysis of ester prodrugs or drugs containing sensitive ester groups may be a limiting factor for the buccal absorption of such compounds. Using the isopropyl carbonate ester of ketobemidone as a model substance of a hydrolysis-sensitive prodrug the esterase activity...... of human saliva has been characterized as a function of various factors. The esterase activity was found to decrease rapidly upon storage of the saliva at 37°C. The activity increased with increasing pH in the range 4.5-7.4 and with increasing salivation flow rate up to a rate of 0.9 ml min. Under resting...... conditions, the flow rate was about 0.2 ml min which implied a greatly decreased esterase activity. The activity was highest after fasting and decreased after intake of a meal. The intraindividual variation in the saliva esterase activity was small whereas a larger interindividual variation was found....

  2. The role of NH2-terminal positive charges in the activity of inward rectifier KATP channels.

    Science.gov (United States)

    Cukras, C A; Jeliazkova, I; Nichols, C G

    2002-09-01

    Approximately half of the NH(2) terminus of inward rectifier (Kir) channels can be deleted without significant change in channel function, but activity is lost when more than approximately 30 conserved residues before the first membrane spanning domain (M1) are removed. Systematic replacement of the positive charges in the NH(2) terminus of Kir6.2 with alanine reveals several residues that affect channel function when neutralized. Certain mutations (R4A, R5A, R16A, R27A, R39A, K47A, R50A, R54A, K67A) change open probability, whereas an overlapping set of mutants (R16A, R27A, K39A, K47A, R50A, R54A, K67A) change ATP sensitivity. Further analysis of the latter set differentiates mutations that alter ATP sensitivity as a consequence of altered open state stability (R16A, K39A, K67A) from those that may affect ATP binding directly (K47A, R50A, R54A). The data help to define the structural determinants of Kir channel function, and suggest possible structural motifs within the NH(2) terminus, as well as the relationship of the NH(2) terminus with the extended cytoplasmic COOH terminus of the channel.

  3. Phthalate esters in marine algae

    OpenAIRE

    Gezgin, Tuncay; Güven, Kasim Cemal; Akçin, Göksel

    2001-01-01

    Abstract o-Phthalate esters as diethyl phthalate, dibutyl phthalate, di-isobutyl phthalate and diethylhexyl phthalate were identified at surface and inner part of algae collected in the Bosphorus, as Ulva lactuca, Enteromorpha linza, Cystoseria barbata, Pterocladia capillaceaeand Ceramium rubrum. The same esters were also detected in seawater samples taken from the same area. Thus parallelism in pollution was noted between the algae and the surrounding seawater,

  4. Activation of PI3K/Akt signaling by n-terminal SH2 domain mutants of the p85α regulatory subunit of PI3K is enhanced by deletion of its c-terminal SH2 domain.

    Science.gov (United States)

    Hofmann, Bianca T; Jücker, Manfred

    2012-10-01

    The phosphoinositide 3-kinase (PI3K) is frequently activated in human cancer cells due to gain of function mutations in the catalytic (p110) and the regulatory (p85) subunits. The regulatory subunit consists of an SH3 domain and two SH2 domains. An oncogenic form of p85α named p65 lacking the c-terminal SH2 domain (cSH2) has been cloned from an irradiation-induced murine thymic lymphoma and transgenic mice expressing p65 in T lymphocytes develop a lymphoproliferative disorder. We have recently detected a c-terminal truncated form of p85α named p76α in a human lymphoma cell line lacking most of the cSH2 domain due to a frame shift mutation. Here, we report that the deletion of the cSH2 domain enhances the activating effects of the n-terminal SH2 domain (nSH2) mutants K379E and R340E on the PI3K/Akt pathway and micro tumor formation in a focus assay. Further analysis revealed that this transforming effect is mediated by activation of the catalytic PI3K isoform p110α and downstream signaling through mTOR. Our data further support a mechanistic model in which mutations of the cSH2 domain of p85α can abrogate its negative regulatory function on PI3K activity via the nSH2 domain of p85α. Copyright © 2012 Elsevier Inc. All rights reserved.

  5. Dual role of the carboxyl-terminal region of pig liver L-kynurenine 3-monooxygenase: mitochondrial-targeting signal and enzymatic activity.

    Science.gov (United States)

    Hirai, Kumiko; Kuroyanagi, Hidehito; Tatebayashi, Yoshitaka; Hayashi, Yoshitaka; Hirabayashi-Takahashi, Kanako; Saito, Kuniaki; Haga, Seiich; Uemura, Tomihiko; Izumi, Susumu

    2010-12-01

    l-kynurenine 3-monooxygenase (KMO) is an NAD(P)H-dependent flavin monooxygenase that catalyses the hydroxylation of l-kynurenine to 3-hydroxykynurenine, and is localized as an oligomer in the mitochondrial outer membrane. In the human brain, KMO may play an important role in the formation of two neurotoxins, 3-hydroxykynurenine and quinolinic acid, both of which provoke severe neurodegenerative diseases. In mosquitos, it plays a role in the formation both of eye pigment and of an exflagellation-inducing factor (xanthurenic acid). Here, we present evidence that the C-terminal region of pig liver KMO plays a dual role. First, it is required for the enzymatic activity. Second, it functions as a mitochondrial targeting signal as seen in monoamine oxidase B (MAO B) or outer membrane cytochrome b(5). The first role was shown by the comparison of the enzymatic activity of two mutants (C-terminally FLAG-tagged KMO and carboxyl-terminal truncation form, KMOΔC50) with that of the wild-type enzyme expressed in COS-7 cells. The second role was demonstrated with fluorescence microscopy by the comparison of the intracellular localization of the wild-type, three carboxyl-terminal truncated forms (ΔC20, ΔC30 and ΔC50), C-terminally FLAG-tagged wild-type and a mutant KMO, where two arginine residues, Arg461-Arg462, were replaced with Ser residues.

  6. Ligand-Controlled Chemoselective C(acyl)–O Bond vs C(aryl)–C Bond Activation of Aromatic Esters in Nickel Catalyzed C(sp2)–C(sp3) Cross-Couplings

    KAUST Repository

    Chatupheeraphat, Adisak

    2018-02-20

    A ligand-controlled and site-selective nickel catalyzed Suzuki-Miyaura cross-coupling reaction with aromatic esters and alkyl organoboron reagents as coupling partners was developed. This methodology provides a facile route for C(sp2)-C(sp3) bond formation in a straightforward fashion by successful suppression of the undesired β-hydride elimination process. By simply switching the phosphorus ligand, the ester substrates are converted into the alkylated arenes and ketone products, respectively. The utility of this newly developed protocol was demonstrated by its wide substrate scope, broad functional group tolerance and application in the synthesis of key intermediates for the synthesis of bioactive compounds. DFT studies on the oxidative addition step helped rationalizing this intriguing reaction chemoselectivity: whereas nickel complexes with bidentate ligands favor the C(aryl)-C bond cleavage in the oxidative addition step leading to the alkylated product via a decarbonylative process, nickel complexes with monodentate phosphorus ligands favor activation of the C(acyl)-O bond, which later generates the ketone product.

  7. Quantified terminal ileal motility during MR enterography as a potential biomarker of Crohn's disease activity: a preliminary study

    International Nuclear Information System (INIS)

    Menys, Alex; Atkinson, David; Ahmed, Asia; Punwani, Shonit; Halligan, Steve; Odille, Freddy; Novelli, Marco; Rodriguez-Justo, Manuel; Proctor, Ian; Taylor, Stuart A.

    2012-01-01

    To compare quantified terminal ileal (TI) motility during MR enterography (MRE) with histopathological severity of acute inflammation in Crohn's disease. A total of 28 Crohn's patients underwent MRE and endoscopic TI biopsy. Axial and coronal TrueFISP, HASTE and post-gadolinium VIBE images were supplemented by multiple coronal TrueFISP cine motility sequences through the small bowel volume. TI motility index (MI) was quantified using validated software; an acute inflammation score (eAIS; 0-6) was assigned to the biopsy. Two observers qualitatively scored mural thickness, T2 signal, contrast enhancement and perimural oedema (0-3) to produce an activity score (aMRIs) based on anatomical MRI. The association among the MI, eAIS and aMRIs was tested using Spearman's rank correlation. Wilcoxon rank sum test compared motility in subjects with and without histopathological inflammation. Mean MI and mean eAIS were 0.27 (range 0.06-0.55) and 1.5 (range 0-5), respectively. There was a significant difference in MI between non-inflamed (mean 0.37, range 0.13-0.55) and inflamed (mean 0.19, range 0.06-0.44) TI, P = 0.002, and a significant negative correlation between MI and both eAIS (Rho = -0.52, P = 0.005) and aMRIs (R = -0.7, P < 0.001). Quantified TI motility negatively correlates with histopathological measures of disease activity and existing anatomical MRI activity biomarkers. (orig.)

  8. Carboxyl-terminal Truncations of ClC-Kb Abolish Channel Activation by Barttin Via Modified Common Gating and Trafficking*

    Science.gov (United States)

    Stölting, Gabriel; Bungert-Plümke, Stefanie; Franzen, Arne; Fahlke, Christoph

    2015-01-01

    ClC-K chloride channels are crucial for auditory transduction and urine concentration. Mutations in CLCNKB, the gene encoding the renal chloride channel hClC-Kb, cause Bartter syndrome type III, a human genetic condition characterized by polyuria, hypokalemia, and alkalosis. In recent years, several Bartter syndrome-associated mutations have been described that result in truncations of the intracellular carboxyl terminus of hClC-Kb. We here used a combination of whole-cell patch clamp, confocal imaging, co-immunoprecipitation, and surface biotinylation to study the functional consequences of a frequent CLCNKB mutation that creates a premature stop codon at Trp-610. We found that W610X leaves the association of hClC-Kb and the accessory subunit barttin unaffected, but impairs its regulation by barttin. W610X attenuates hClC-Kb surface membrane insertion. Moreover, W610X results in hClC-Kb channel opening in the absence of barttin and prevents further barttin-mediated activation. To describe how the carboxyl terminus modifies the regulation by barttin we used V166E rClC-K1. V166E rClC-K1 is active without barttin and exhibits prominent, barttin-regulated voltage-dependent gating. Electrophysiological characterization of truncated V166E rClC-K1 demonstrated that the distal carboxyl terminus is necessary for slow cooperative gating. Since barttin modifies this particular gating process, channels lacking the distal carboxyl-terminal domain are no longer regulated by the accessory subunit. Our results demonstrate that the carboxyl terminus of hClC-Kb is not part of the binding site for barttin, but functionally modifies the interplay with barttin. The loss-of-activation of truncated hClC-Kb channels in heterologous expression systems fully explains the reduced basolateral chloride conductance in affected kidneys and the clinical symptoms of Bartter syndrome patients. PMID:26453302

  9. Calcium has a permissive role in interleukin-1beta-induced c-jun N-terminal kinase activation in insulin-secreting cells

    DEFF Research Database (Denmark)

    Størling, Joachim; Zaitsev, Sergei V; Kapelioukh, Iouri L

    2005-01-01

    The c-jun N-terminal kinase (JNK) signaling pathway mediates IL-1beta-induced apoptosis in insulin-secreting cells, a mechanism relevant to the destruction of pancreatic beta-cells in type 1 and 2 diabetes. However, the mechanisms that contribute to IL-1beta activation of JNK in beta-cells are la...

  10. Differential cellulolytic activity of native-form and C-terminal tagged-form cellulase derived from coptotermes formosanus and expressed in E. coli

    Science.gov (United States)

    The endogenous cellulase gene (CfEG3a) of Coptotermes formosanus, an economically important pest termite, was cloned and overexpressed in both native form (nCfEG) and C-terminal His-tagged form (tCfEG) in E.coli. Both forms of recombinant cellulases showed hydrolytic activity on cellulosic substrate...

  11. Is the modified Tardieu scale in semi-standing position better associated with knee extension and hamstring activity in terminal swing than the supine Tardieu?

    NARCIS (Netherlands)

    Faber, I.R.; Nienhuis, B.; Rijs, N.P.; Geurts, A.C.H.; Duysens, J.E.J.

    2008-01-01

    The aim of this study was to investigate whether the modified Tardieu scale (MTS) in a semi-standing position, used for the assessment of hamstrings spasticity, was better associated with knee extension and hamstrings activity in terminal swing than the MTS in a supine position in children with

  12. The drug-binding activity of the multidrug-responding transcriptional regulator BmrR resides in its C-terminal domain.

    OpenAIRE

    Markham, P N; Ahmed, M; Neyfakh, A A

    1996-01-01

    Rhodamine and tetraphenylphosphonium, the substrates of the Bacillus subtilis multidrug efflux transporter Bmr, induce the expression of Bmr through direct interaction with its transcriptional activator BmrR. Here we show that the C-terminal domain of BmrR, expressed individually, binds both these compounds and therefore can be used as a model for molecular analysis of the phenomenon of multidrug recognition.

  13. Structural Insight into the Critical Role of the N-Terminal Region in the Catalytic Activity of Dual-Specificity Phosphatase 26.

    Directory of Open Access Journals (Sweden)

    Eun-Young Won

    Full Text Available Human dual-specificity phosphatase 26 (DUSP26 is a novel target for anticancer therapy because its dephosphorylation of the p53 tumor suppressor regulates the apoptosis of cancer cells. DUSP26 inhibition results in neuroblastoma cell cytotoxicity through p53-mediated apoptosis. Despite the previous structural studies of DUSP26 catalytic domain (residues 61-211, DUSP26-C, the high-resolution structure of its catalytically active form has not been resolved. In this study, we determined the crystal structure of a catalytically active form of DUSP26 (residues 39-211, DUSP26-N with an additional N-terminal region at 2.0 Å resolution. Unlike the C-terminal domain-swapped dimeric structure of DUSP26-C, the DUSP26-N (C152S monomer adopts a fold-back conformation of the C-terminal α8-helix and has an additional α1-helix in the N-terminal region. Consistent with the canonically active conformation of its protein tyrosine phosphate-binding loop (PTP loop observed in the structure, the phosphatase assay results demonstrated that DUSP26-N has significantly higher catalytic activity than DUSP26-C. Furthermore, size exclusion chromatography-multiangle laser scattering (SEC-MALS measurements showed that DUSP26-N (C152S exists as a monomer in solution. Notably, the crystal structure of DUSP26-N (C152S revealed that the N-terminal region of DUSP26-N (C152S serves a scaffolding role by positioning the surrounding α7-α8 loop for interaction with the PTP-loop through formation of an extensive hydrogen bond network, which seems to be critical in making the PTP-loop conformation competent for phosphatase activity. Our study provides the first high-resolution structure of a catalytically active form of DUSP26, which will contribute to the structure-based rational design of novel DUSP26-targeting anticancer therapeutics.

  14. The C-terminal domain of the Arabidopsis AtMBD7 protein confers strong chromatin binding activity

    International Nuclear Information System (INIS)

    Zemach, Assaf; Paul, Laju K.; Stambolsky, Perry; Efroni, Idan; Rotter, Varda; Grafi, Gideon

    2009-01-01

    The Arabidopsis MBD7 (AtMBD7) - a naturally occurring poly MBD protein - was previously found to be functional in binding methylated-CpG dinucleotides in vitro and localized to highly methylated chromocenters in vivo. Furthermore, AtMBD7 has significantly lower mobility within the nucleus conferred by cooperative activity of its three MBD motifs. Here we show that besides the MBD motifs, AtMBD7 possesses a strong chromatin binding domain located at its C-terminus designated sticky-C (StkC). Mutational analysis showed that a glutamic acid residue near the C-terminus is essential though not sufficient for the StkC function. Further analysis demonstrated that this motif can render nuclear proteins highly immobile both in plant and animal cells, without affecting their native subnuclear localization. Thus, the C-terminal, StkC motif plays an important role in fastening AtMBD7 to its chromosomal, CpG-methylated sites. It may be possible to utilize this motif for fastening nuclear proteins to their chromosomal sites both in plant and animal cells for research and gene therapy applications.

  15. Organization of industrial maintenance in oil pipeline and terminals activities: a project for the implantation of a corporative management system

    Energy Technology Data Exchange (ETDEWEB)

    Correia, Paulo de Tarso Arruda [TRANSPETRO - PETROBRAS Transporte S.A., Rio de Janeiro, RJ (Brazil). Diretoria de Terminais e Oleodutos; Arruda, Daniela Mendonca; Oliveira, Italo Luiz [TRANSPETRO - PETROBRAS Transporte S.A., Rio de Janeiro, RJ (Brazil)

    2009-07-01

    This paper discusses the definition and implementation of a corporate management model for industrial maintenance within TRANSPETRO's Terminals and Oil Pipelines business segment. A project is under way to answer the company's needs for better coordination of its maintenance activities as well as to face the challenge of increasing performance with higher systems and equipment' availability, at lower costs. To achieve this target, the project has been employing updating management tools for industrial maintenance planning and control. Its scope comprises the definition of: industrial maintenance process guidelines; industrial maintenance normative requirements and operational procedures; industrial maintenance performance indicators; local organizational charts; training of maintenance personnel; qualification and certification policies; conceptualization of maintenance engineering and maintenance based on risk; updating technologies such as asset management; warehousing and logistics for maintenance support in the supply of spare parts and materials. The project will also consider the results of a previous strategic sourcing study, concerning the definition of the most suitable out sourcing strategy for each operational unit, considering its characteristics as well as the characteristics of the region where it is located. (author)

  16. Organization of industrial maintenance in oil pipeline and terminals activities: a project for the implantation of a corporative management system

    Energy Technology Data Exchange (ETDEWEB)

    Correia, Paulo de Tarso Arruda [TRANSPETRO - PETROBRAS Transporte S.A., Rio de Janeiro, RJ (Brazil). Diretoria de Terminais e Oleodutos; Arruda, Daniela Mendonca; Oliveira, Italo Luiz [TRANSPETRO - PETROBRAS Transporte S.A., Rio de Janeiro, RJ (Brazil)

    2009-07-01

    This paper discusses the definition and implementation of a corporate management model for industrial maintenance within TRANSPETRO's Terminals and Oil Pipelines business segment. A project is under way to answer the company's needs for better coordination of its maintenance activities as well as to face the challenge of increasing performance with higher systems and equipment' availability, at lower costs. To achieve this target, the project has been employing updating management tools for industrial maintenance planning and control. Its scope comprises the definition of: industrial maintenance process guidelines; industrial maintenance normative requirements and operational procedures; industrial maintenance performance indicators; local organizational charts; training of maintenance personnel; qualification and certification policies; conceptualization of maintenance engineering and maintenance based on risk; updating technologies such as asset management; warehousing and logistics for maintenance support in the supply of spare parts and materials. The project will also consider the results of a previous strategic sourcing study, concerning the definition of the most suitable out sourcing strategy for each operational unit, considering its characteristics as well as the characteristics of the region where it is located. (author)

  17. Synthesis and antimalarial testing of neocryptolepine analogues: addition of ester function in SAR study of 2,11-disubstituted indolo[2,3-b]quinolines.

    Science.gov (United States)

    Lu, Wen-Jie; Wicht, Kathryn J; Wang, Li; Imai, Kento; Mei, Zhen-Wu; Kaiser, Marcel; El Sayed, Ibrahim El Tantawy; Egan, Timothy J; Inokuchi, Tsutomu

    2013-06-01

    This report describes the synthesis, and in vitro and in vivo antimalarial evaluations of certain ester-modified neocryptolepine (5-methyl-5H-indolo[2,3-b]quinoline) derivatives. The modifications were carried out by introducing ester groups at the C2 and/or C9 position on the neocryptolepine core and the terminal amino group of the 3-aminopropylamine substituents at the C11 position with a urea/thiourea unit. The antiplasmodial activities of our derivative agents against two different strains (CQS: NF54, and CQR: K1) and the cytotoxic activity against normal L6 cells were evaluated. The test results showed that the ester modified neocryptolepine derivatives have higher antiplasmodial activities against both strains and a low cytotoxic activity against normal cells. The best results were achieved by compounds 9c and 12b against the NF54 strain with the IC50/SI value as 2.27 nM/361 and 1.81 nM/321, respectively. While against K1 strain, all the tested compounds showed higher activity than the well-known antimalarial drug chloroquine. Furthermore, the compounds were tested for β-haematin inhibition and 12 were found to be more active than chloroquine (IC50 = 18 μM). Structure activity relationship studies exposed an interesting linear correlation between polar surface area of the molecule and β-haematin inhibition for this series. In vivo testing of compounds 7 and 8a against NF54 strain on Plasmodium berghei female mice showed that the introduction of the ester group increased the antiplasmodial activity of the neocryptolepine core substantially. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  18. Structure-activity relationship studies of 1,7-diheteroarylhepta-1,4,6-trien-3-ones with two different terminal rings in prostate epithelial cell models.

    Science.gov (United States)

    Wang, Rubing; Zhang, Xiaojie; Chen, Chengsheng; Chen, Guanglin; Sarabia, Cristian; Zhang, Qiang; Zheng, Shilong; Wang, Guangdi; Chen, Qiao-Hong

    2017-06-16

    To systematically investigate the structure-activity relationships of 1,7-diheteroarylhepta-1,4,6-trien-3-ones in three human prostate cancer cell models and one human prostate non-neoplastic epithelial cell model, thirty five 1,7-diarylhepta-1,4,6-trien-3-ones with different terminal heteroaromatic rings have been designed for evaluation of their anti-proliferative potency in vitro. These target compounds have been successfully synthesized through two sequential Horner-Wadsworth-Emmons reactions starting from the appropriate aldehydes and tetraethyl (2-oxopropane-1,3-diyl)bis(phosphonate). Their anti-proliferative potency against PC-3, DU-145 and LNCaP human prostate cancer cell lines can be significantly enhanced by the manipulation of the terminal heteroaromatic rings, further demonstrating the utility of 1,7-diarylhepta-1,4,6-trien-3-one as a potential scaffold for the development of anti-prostate cancer agents. The optimal analog 40 is 82-, 67-, and 39-fold more potent than curcumin toward the three prostate cancer cell lines, respectively. The experimental data also reveal that the trienones with two different terminal aromatic rings possess greater potency toward three prostate cancer cell lines, but also have greater capability of suppressing the proliferation of PWR-1E benign human prostate epithelial cells, as compared to the corresponding counterparts with two identical terminal rings and curcumin. The terminal aromatic rings also affect the cell apoptosis perturbation. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  19. Chain propagation and termination mechanisms for polymerization of conjugated polar alkenes by [Al]-based frustrated Lewis pairs

    KAUST Repository

    He, Jianghua

    2014-11-25

    A combined experimental and theoretical study on mechanistic aspects of polymerization of conjugated polar alkenes by frustrated Lewis pairs (FLPs) based on N-heterocyclic carbene (NHC) and Al(C6F5)3 pairs is reported. This study consists of three key parts: structural characterization of active propagating intermediates, propagation kinetics, and chain-termination pathways. Zwitterionic intermediates that simulate the active propagating species in such polymerization have been generated or isolated from the FLP activation of monomers such as 2-vinylpyridine and 2-isopropenyl-2-oxazoline-one of which, IMes+-CH2C(Me)=(C3H2NO)Al(C6F5)3 - (2), has been structurally characterized. Kinetics performed on the polymerization of 2-vinylpyridine by ItBu/Al(C6F5)3 revealed that the polymerization follows a zero-order dependence on monomer concentration and a first-order dependence on initiator (ItBu) and activator [Al(C6F5)3] concentrations, indicating a bimolecular, activated monomer propagation mechanism. The Lewis pair polymerization of conjugate polar alkenes such as methacrylates is accompanied by competing chain-termination side reactions; between the two possible chain-termination pathways, the one that proceeds via intramolecular backbiting cyclization involving nucleophilic attack of the activated ester group of the growing polymer chain by the O-ester enolate active chain end to generate a six-membered lactone (δ-valerolactone)-terminated polymer chain is kinetically favored, but thermodynamically disfavored, over the pathway leading to the -ketoester-terminated chain, as revealed by computational studies.

  20. Preparation of Substituted Enol Derivatives From Terminal Alkynes and Their Synthetic Utility

    Science.gov (United States)

    DeBergh, John R.; Spivey, Kathleen M.; Ready, Joseph M.

    2009-01-01

    Stereodefined enol derivatives of aldehydes are prepared from terminal alkynes. Specifically, terminal alkynes are known to undergo Cp2ZrCl2-catalyzed methylalumination. Here, we show that the resultant vinylalanes can be oxygenated with peroxyzinc species to generate trisubstituted enolates. Electrophilic trapping with carboxylic anydrides or silyl triflates yields trisubstituted enol esters or silanes, respectively. The tandem carbometalation/oxygenation tolerates free and protected alcohols, heterocycles, olefins and nitriles. Likewise, amination can be accomplished using azodicarboxylates. Stereodefined enol esters can undergo asymmetric dihydroxylation to yield optically-active α-hydroxy aldehydes. Reduction with NaBH4 provides the diols of 1,1-disubstituted olefins in excellent ee. An application of this methodology to the enantioselective synthesis of the insect pheromone frontalin is presented. Finally, α-hydroxy aldehydes are shown to undergo homologation to a terminal alkyne, reductive amination, oxidation and olefination. Preliminary results indicate that tandem carbometalation/amination can be accomplished with azodicarboxylates. In this way, ene-hydrazines are formed in excellent yield. PMID:18517202

  1. Triptolide, a diterpenoid triepoxide, induces antitumor proliferation via activation of c-Jun NH2-terminal kinase 1 by decreasing phosphatidylinositol 3-kinase activity in human tumor cells

    International Nuclear Information System (INIS)

    Miyata, Yoshiki; Sato, Takashi; Ito, Akira

    2005-01-01

    Triptolide, a diterpenoid triepoxide extracted from the Chinese herb Tripterygium wilfordii Hook f., exerts antitumorigenic actions against several tumor cells, but the intracellular target signal molecule(s) for this antitumorigenesis activity of triptolide remains to be identified. In the present study, we demonstrated that triptolide, in a dose-dependent manner, inhibited the proliferation of human fibrosarcoma HT-1080, human squamous carcinoma SAS, and human uterine cervical carcinoma SKG-II cells. In addition, triptolide was found to decrease phosphatidylinositol 3-kinase (PI3K) activity. A PI3K inhibitor, LY-294002, mimicked the triptolide-induced antiproliferative activity in HT-1080, SAS, and SKG-II cells. There was no change in the activity of Akt or protein kinase C (PKC), both of which are downstream effectors in the PI3K pathway. Furthermore, the phosphorylation of Ras, Raf, and mitogen-activated protein/extracellular signal-regulated kinase 1/2 was not modified in HT-1080 cells treated with triptolide. However, the phosphorylation of c-Jun NH 2 -terminal kinase 1 (JNK1) was found to increase in both triptolide- and LY-294002-treated cells. Furthermore, the triptolide-induced inhibition of HT-1080 cell proliferation was not observed by JNK1 siRNA-treatment. These results provide novel evidence that PI3K is a crucial target molecule in the antitumorigenic action of triptolide. They further suggest a possible triptolide-induced inhibitory signal for tumor cell proliferation that is initiated by the decrease in PI3K activity, which in turn leads to the augmentation of JNK1 phosphorylation via the Akt and/or PKC-independent pathway(s). Moreover, it is likely that the activation of JNK1 is required for the triptolide-induced inhibition of tumor proliferation

  2. Sonolytic and Silent Polymerization of Methacrlyic Acid Butyl Ester Catalyzed by a New Onium Salt with bis-Active Sites in a Biphasic System — A Comparative Investigation

    Directory of Open Access Journals (Sweden)

    Perumberkandgai A. Vivekanand

    2013-02-01

    Full Text Available Currently, ingenious new analytical and process experimental techniques which are environmentally benign techniques, viz., ultrasound irradiation, have become immensely popular in promoting various reactions. In this work, a novel soluble multi-site phase transfer catalyst (PTC viz., 1,4-bis-(propylmethyleneammounium chloridebenzene (BPMACB was synthesized and its catalytic efficiency was assessed by observing the kinetics of sonolytic polymerization of methacrylic acid butyl ester (MABE using potassium persulphate (PPS as an initiator. The ultrasound–multi-site phase transfer catalysis (US-MPTC-assisted polymerization reaction was compared with the silent (non-ultrasonic polymerization reaction. The effects of the catalyst and various reaction parameters on the catalytic performance were in detail investigated by following the kinetics of polymerization of MABE in an ethyl acetate-water biphasic system. From the detailed kinetic investigation we propose a plausible mechanism. Further the kinetic results demonstrate clearly that ultrasound-assisted phase-transfer catalysis significantly increased the reaction rate when compared to silent reactions. Notably, this environmentally benign and cost-effective process has great potential to be applied in various polymer industries.

  3. Terminal Ballistics

    CERN Document Server

    Rosenberg, Zvi

    2012-01-01

    This book covers the important issues of terminal ballistics in a comprehensive way combining experimental data, numerical simulations and analytical modeling. The first chapter reviews the experimental equipment which are used for ballistic tests and the diagnostics for material characterization under impulsive loading conditions. The second chapter covers essential features of the codes which are used for terminal ballistics such as the Euler vs. Lagrange schemes and meshing techniques, as well as the most popular material models. The third chapter, devoted to the penetration mechanics of rigid penetrators, brings the update of modeling in this field. The fourth chapter deals with plate perforation and the fifth chapter deals with the penetration mechanics of shaped charge jets and eroding long rods. The last two chapters discuss several techniques for the disruption and defeating of the main threats in armor design. Throughout the book the authors demonstrate the advantages of numerical simulations in unde...

  4. Terminal structure

    Science.gov (United States)

    Schmidt, Frank [Langenhagen, DE; Allais, Arnaud [Hannover, DE; Mirebeau, Pierre [Villebon sur Yvette, FR; Ganhungu, Francois [Vieux-Reng, FR; Lallouet, Nicolas [Saint Martin Boulogne, FR

    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.

  5. Synthesis of novel vitamin K derivatives with alkylated phenyl groups introduced at the ω-terminal side chain and evaluation of their neural differentiation activities.

    Science.gov (United States)

    Sakane, Rie; Kimura, Kimito; Hirota, Yoshihisa; Ishizawa, Michiyasu; Takagi, Yuta; Wada, Akimori; Kuwahara, Shigefumi; Makishima, Makoto; Suhara, Yoshitomo

    2017-11-01

    Vitamin K is an essential cofactor of γ-glutamylcarboxylase as related to blood coagulation and bone formation. Menaquinone-4, one of the vitamin K homologues, is biosynthesized in the body and has various biological activities such as being a ligand for steroid and xenobiotic receptors, protection of neuronal cells from oxidative stress, and so on. From this background, we focused on the role of menaquinone in the differentiation activity of progenitor cells into neuronal cells and we synthesized novel vitamin K derivatives with modification of the ω-terminal side chain. We report here new vitamin K analogues, which introduced an alkylated phenyl group at the ω-terminal side chain. These compounds exhibited potent differentiation activity as compared to control. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  6. Long Terminal Repeat Circular DNA as Markers of Active Viral Replication of Human T Lymphotropic Virus-1 in Vivo

    Directory of Open Access Journals (Sweden)

    James M Fox

    2016-03-01

    Full Text Available Clonal expansion of human T-lymphotropic virus type-1 (HTLV-1 infected cells in vivo is well documented. Unlike human immunodeficiency virus type 1 (HIV-1, HTLV-1 plasma RNA is sparse. The contribution of the “mitotic” spread of HTLV-1 compared with infectious spread of the virus to HTLV-1 viral burden in established infection is uncertain. Since extrachromosomal long terminal repeat (LTR DNA circles are indicators of viral replication in HIV-1 carriers with undetectable plasma HIV RNA, we hypothesised that HTLV-1 LTR circles could indicate reverse transcriptase (RT usage and infectious activity. 1LTR and 2LTR DNA circles were measured in HTLV-1 cell lines and peripheral blood mononuclear cells (PBMC of asymptomatic carriers (ACs and patients with HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP or adult T cell leukaemia/lymphoma (ATLL. 1LTR DNA circles were detected in 14/20 patients at a mean of 1.38/100 PBMC but did not differentiate disease status nor correlate with HTLV-1 DNA copies. 2LTR DNA circles were detected in 30/31 patients and at higher concentrations in patients with HTLV-1-associated diseases, independent of HTLV-1 DNA load. In an incident case the 2LTR DNA circle concentration increased 2.1 fold at the onset of HAM/TSP compared to baseline. Detectable and fluctuating levels of HTLV-1 DNA circles in patients indicate viral RT usage and virus replication. Our results indicate HTLV-1 viral replication capacity is maintained in chronic infection and may be associated with disease onset.

  7. Carboxyl-terminal Truncations of ClC-Kb Abolish Channel Activation by Barttin Via Modified Common Gating and Trafficking.

    Science.gov (United States)

    Stölting, Gabriel; Bungert-Plümke, Stefanie; Franzen, Arne; Fahlke, Christoph

    2015-12-18

    ClC-K chloride channels are crucial for auditory transduction and urine concentration. Mutations in CLCNKB, the gene encoding the renal chloride channel hClC-Kb, cause Bartter syndrome type III, a human genetic condition characterized by polyuria, hypokalemia, and alkalosis. In recent years, several Bartter syndrome-associated mutations have been described that result in truncations of the intracellular carboxyl terminus of hClC-Kb. We here used a combination of whole-cell patch clamp, confocal imaging, co-immunoprecipitation, and surface biotinylation to study the functional consequences of a frequent CLCNKB mutation that creates a premature stop codon at Trp-610. We found that W610X leaves the association of hClC-Kb and the accessory subunit barttin unaffected, but impairs its regulation by barttin. W610X attenuates hClC-Kb surface membrane insertion. Moreover, W610X results in hClC-Kb channel opening in the absence of barttin and prevents further barttin-mediated activation. To describe how the carboxyl terminus modifies the regulation by barttin we used V166E rClC-K1. V166E rClC-K1 is active without barttin and exhibits prominent, barttin-regulated voltage-dependent gating. Electrophysiological characterization of truncated V166E rClC-K1 demonstrated that the distal carboxyl terminus is necessary for slow cooperative gating. Since barttin modifies this particular gating process, channels lacking the distal carboxyl-terminal domain are no longer regulated by the accessory subunit. Our results demonstrate that the carboxyl terminus of hClC-Kb is not part of the binding site for barttin, but functionally modifies the interplay with barttin. The loss-of-activation of truncated hClC-Kb channels in heterologous expression systems fully explains the reduced basolateral chloride conductance in affected kidneys and the clinical symptoms of Bartter syndrome patients. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  8. Termination unit

    Energy Technology Data Exchange (ETDEWEB)

    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.

  9. Characterization of glutamate decarboxylase from Lactobacillus plantarum and its C-terminal function for the pH dependence of activity.

    Science.gov (United States)

    Shin, Sun-Mi; Kim, Hana; Joo, Yunhye; Lee, Sang-Jae; Lee, Yong-Jik; Lee, Sang Jun; Lee, Dong-Woo

    2014-12-17

    The gadB gene encoding glutamate decarboxylase (GAD) from Lactobacillus plantarum was cloned and expressed in Escherichia coli. The recombinant enzyme exhibited maximal activity at 40 °C and pH 5.0. The 3D model structure of L. plantarum GAD proposed that its C-terminal region (Ile454-Thr468) may play an important role in the pH dependence of catalysis. Accordingly, C-terminally truncated (Δ3 and Δ11 residues) mutants were generated and their enzyme activities compared with that of the wild-type enzyme at different pH values. Unlike the wild-type GAD, the mutants showed pronounced catalytic activity in a broad pH range of 4.0-8.0, suggesting that the C-terminal region is involved in the pH dependence of GAD activity. Therefore, this study may provide effective target regions for engineering pH dependence of GAD activity, thereby meeting industrial demands for the production of γ-aminobutyrate in a broad range of pH values.

  10. Environmental effect of rapeseed oil ethyl ester

    International Nuclear Information System (INIS)

    Makareviciene, V.; Janulis, P.

    2003-01-01

    Exhaust emission tests were conducted on rapeseed oil methyl ester (RME), rapeseed oil ethyl ester (REE) and fossil diesel fuel as well as on their mixtures. Results showed that when considering emissions of nitrogen oxides (NO x ), carbon monoxide (CO) and smoke density, rapeseed oil ethyl ester had less negative effect on the environment in comparison with that of rapeseed oil methyl ester. When fuelled with rapeseed oil ethyl ester, the emissions of NO x showed an increase of 8.3% over those of fossil diesel fuel. When operated on 25-50% bio-ester mixed with fossil diesel fuel, NO x emissions marginally decreased. When fuelled with pure rapeseed oil ethyl ester, HC emissions decreased by 53%, CO emissions by 7.2% and smoke density 72.6% when compared with emissions when fossil diesel fuel was used. Carbon dioxide (CO 2 ) emissions, which cause greenhouse effect, decreased by 782.87 g/kWh when rapeseed oil ethyl ester was used and by 782.26 g/kWh when rapeseed oil methyl ester was used instead of fossil diesel fuel. Rapeseed oil ethyl ester was more rapidly biodegradable in aqua environment when compared with rapeseed oil methyl ester and especially with fossil diesel fuel. During a standard 21 day period, 97.7% of rapeseed oil methyl ester, 98% of rapeseed oil ethyl ester and only 61.3% of fossil diesel fuel were biologically decomposed. (author)

  11. Avocado and olive oil methyl esters

    International Nuclear Information System (INIS)

    Knothe, Gerhard

    2013-01-01

    Biodiesel, the mono-alkyl esters of vegetable oils, animal fats or other triacylglycerol-containing materials and an alternative to conventional petroleum-based diesel fuel, has been derived from a variety of feedstocks. Numerous feedstocks have been investigated as potential biodiesel sources, including commodity oils, however, the methyl esters of avocado and olive oil would likely be suitable as biodiesel fuel. In order to expand the database and comprehensive evaluation of the properties of vegetable oil esters, in this work the fuel-related properties of avocado and olive oil methyl esters, which exhibit similar fatty acid profiles including high oleic acid content, are determined. The cetane numbers of avocado oil methyl esters and olive oil methyl esters are relatively high, determined as 59.2 and 62.5, respectively, due to their elevated content of methyl oleate. Other properties are well within the ranges specified in biodiesel standards. The cloud points of both esters are slightly above 0 °C due to their content of saturated esters, especially methyl palmitate. Overall, avocado and olive oil yield methyl esters with fuel properties comparable to methyl esters from other commodity vegetable oils. The 1 H and 13 C NMR spectra of avocado and olive oil methyl esters are reported. -- Highlights: • Methyl esters of avocado and olive oil meet biodiesel fuel standards. • Provides comparison for methyl esters of other vegetable oils with high oleic content. • Discusses and compares present results with prior literature

  12. Triazole–Au(I complex as chemoselective catalyst in promoting propargyl ester rearrangements

    Directory of Open Access Journals (Sweden)

    Dawei Wang

    2011-07-01

    Full Text Available Triazole–Au (TA–Au catalysts were employed in several transformations involving propargyl ester rearrangement. Good chemoselectivity was observed, which allowed the effective activation of the alkyne without affecting the reactivity of the allene ester intermediates. These results led to the investigation of the preparation of allene ester intermediates with TA–Au catalysts under anhydrous conditions. As expected, the desired 3,3-rearrangement products were obtained in excellent yields (generally >90% yields with 1% loading. Besides the typical ester migrating groups, carbonates and carbamates were also found to be suitable for this transformation, which provided a highly efficient, practical method for the preparation of substituted allenes.

  13. Synthesis of amide-functionalized cellulose esters by olefin cross-metathesis.

    Science.gov (United States)

    Meng, Xiangtao; Edgar, Kevin J

    2015-11-05

    Cellulose esters with amide functionalities were synthesized by cross-metathesis (CM) reaction of terminally olefinic esters with different acrylamides, catalyzed by Hoveyda-Grubbs 2nd generation catalyst. Chelation by amides of the catalyst ruthenium center caused low conversions using conventional solvents. The effects of both solvent and structure of acrylamide on reaction conversion were investigated. While the inherent tendency of acrylamides to chelate Ru is governed by the acrylamide N-substituents, employing acetic acid as a solvent significantly improved the conversion of certain acrylamides, from 50% to up to 99%. Homogeneous hydrogenation using p-toluenesulfonyl hydrazide successfully eliminated the α,β-unsaturation of the CM products to give stable amide-functionalized cellulose esters. The amide-functionalized product showed higher Tg than its starting terminally olefinic counterpart, which may have resulted from strong hydrogen bonding interactions of the amide functional groups. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Morphostructural evidence for Recent/active extension in Central Tanzania beyond the southern termination of the Kenya Rift.

    Science.gov (United States)

    Le Gall, B.; Rolet, J.; Gernigon, L.; Ebinger, C.; Gloaguen, R.

    2003-04-01

    The southern tip zone of the Kenya Rift on the eastern branch of the East African System is usually thought to occur in the so-called North Tanzanian Divergence. In this region, the narrow (50 km-wide) axial graben of southern Kenya splays southwards, via a major EW-trending volcanic lineament, into a 200 km-wide broad rifted zone with three separate arms of normal faulting and tilted fault blocks (Eyasi, Manyara and Pangani arms from W to E). Remote sensing analysis from Central Tanzania demonstrates that rift morphology exists over an area lying 400 km beyond the southern termination of the Kenya Rift. The most prominent rift structures are observed in the Kilombero region and consist of a 100 km-wide range of uplifted basement blocks fringed to the west by an E-facing half-graben inferred to reach depths of 6-8 km from aeromagnetic dataset. Physiographic features (fault scarps), and river drainage anomalies suggest that the present-day rift pattern in the Kilombero extensional province principally results from Recent/Neogene deformation. That assumption is also supported by the seismogenic character of a number of faults. The Kilombero half-graben is superimposed upon an earlier rift system, Karoo in age, which is totally overprinted and is only evidenced from its sedimentary infill. On the other hand, the nature and thickness of the inferred Neogene synrift section is still unknown. The Kilombero rifted zone is assumed to connect northwards into the central rift arm (Manyara) of the South Kenya Rift via a seismically active transverse fault zone that follows ductile fabrics within the Mozambican crystalline basement. The proposed rift model implies that incipient rifting propagates hroughout the cold and strong crust/lithosphere of Central Tanzania along Proterozoic (N140=B0E) basement weakness zones and earlier Karoo (NS)rift structures. A second belt of Recent-active linked fault/basins also extends further East from the Pangani rift arm to the offshore

  15. Liquid Crystalline Thermosets from Ester, Ester-imide, and Ester-amide Oligomers

    Science.gov (United States)

    Dingemans, Theodorus J. (Inventor); Weiser, Erik S. (Inventor); St. Clair, Terry L. (Inventor)

    2009-01-01

    Main chain thermotropic liquid crystal esters, ester-imides, and ester-amides were prepared from AA, BB, and AB type monomeric materials and end-capped with phenylacetylene, phenylmaleimide, or nadimide reactive end-groups. The end-capped liquid crystal oligomers are thermotropic and have, preferably, molecular weights in the range of approximately 1000-15,000 grams per mole. The end-capped liquid crystaloligomers have broad liquid crystalline melting ranges and exhibit high melt stability and very low melt viscosities at accessible temperatures. The end-capped liquid crystal oli-gomers are stable forup to an hour in the melt phase. They are highly processable by a variety of melt process shape forming and blending techniques. Once processed and shaped, the end-capped liquid crystal oigomers were heated to further polymerize and form liquid crystalline thermosets (LCT). The fully cured products are rubbers above their glass transition temperatures.

  16. Surface activity evaluation of an arabinose ester as water/oil demulsifier at severe conditions of temperature, salinity and pH; Avaliacao da atividade superficial de um ester de arabinose, como desemulsificante agua/oleo, em condicoes severas de temperatura, salinidade e pH

    Energy Technology Data Exchange (ETDEWEB)

    Borges, Mauricio Rodrigues; Garcia, Rosangela Balaban; Santos, Jaciara Alves dos; Vieira, Mariane; Silva, Luciana Carvalho; Campos, Viviane de Oliveira; Silva, Rayane Araujo da; Santos, Telma Pitanga dos [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)

    2008-07-01

    This work had for objective to compare the superficial properties of an arabinose ester, no-ionic, nontoxic, biodegradable, with two commercial products: the first one based on sodium dodecyl sulfate and the second one based on poly-oxy alkylene phenol formaldehyde. The arabinose ester was synthesized on the Petroleum Research Laboratory - UFRN, through enzymatic catalysis by protease from Bacillus subtilis, using arabinose and vegetable oil, in organic medium. In previous work [1], this sugar ester was evaluated as a possible water/oil demulsifier and the results were compared with the results of the commercial product based on poly-oxy alkylene phenol formaldehyde, showing that, for certain reaction conditions, the sugar ester presented better acting (71%) that the commercial product (33%) as demulsifier. In this work, the stability of this arabinose ester was evaluated in severe conditions of temperature, salinity and pH, through superficial tests in a tensiometer, using Wilhelmy plate method and the results were compared with the results obtained for two commercial products above mentioned. (author)

  17. Mechanical properties and chemical stability of pivalolactone-based poly(ether ester)s

    NARCIS (Netherlands)

    Tijsma, E.J.; Tijsma, E.J.; van der Does, L.; Bantjes, A.; Bantjes, A.; Vulic, I.

    1994-01-01

    The processing, mechanical and chemical properties of poly(ether ester)s, prepared from pivalolactone (PVL), 1,4-butanediol (4G) and dimethyl terephthalate (DMT), were studied. The poly(ether ester)s could easily be processed by injection moulding, owing to their favourable rheological and thermal

  18. The N-terminal domain of Slack determines the formation and trafficking of Slick/Slack heteromeric sodium-activated potassium channels.

    Science.gov (United States)

    Chen, Haijun; Kronengold, Jack; Yan, Yangyang; Gazula, Valeswara-Rao; Brown, Maile R; Ma, Liqun; Ferreira, Gonzalo; Yang, Youshan; Bhattacharjee, Arin; Sigworth, Fred J; Salkoff, Larry; Kaczmarek, Leonard K

    2009-04-29

    Potassium channels activated by intracellular Na(+) ions (K(Na)) play several distinct roles in regulating the firing patterns of neurons, and, at the single channel level, their properties are quite diverse. Two known genes, Slick and Slack, encode K(Na) channels. We have now found that Slick and Slack subunits coassemble to form heteromeric channels that differ from the homomers in their unitary conductance, kinetic behavior, subcellular localization, and response to activation of protein kinase C. Heteromer formation requires the N-terminal domain of Slack-B, one of the alternative splice variants of the Slack channel. This cytoplasmic N-terminal domain of Slack-B also facilitates the localization of heteromeric K(Na) channels to the plasma membrane. Immunocytochemical studies indicate that Slick and Slack-B subunits are coexpressed in many central neurons. Our findings provide a molecular explanation for some of the diversity in reported properties of neuronal K(Na) channels.

  19. Inactivation of Mechanically Activated Piezo1 Ion Channels Is Determined by the C-Terminal Extracellular Domain and the Inner Pore Helix

    Directory of Open Access Journals (Sweden)

    Jason Wu

    2017-11-01

    Full Text Available Piezo proteins form mechanically activated ion channels that are responsible for our sense of light touch, proprioception, and vascular blood flow. Upon activation by mechanical stimuli, Piezo channels rapidly inactivate in a voltage-dependent manner through an unknown mechanism. Inactivation of Piezo channels is physiologically important, as it modulates overall mechanical sensitivity, gives rise to frequency filtering of repetitive mechanical stimuli, and is itself the target of numerous human disease-related channelopathies that are not well understood mechanistically. Here, we identify the globular C-terminal extracellular domain as a structure that is sufficient to confer the time course of inactivation and a single positively charged lysine residue at the adjacent inner pore helix as being required for its voltage dependence. Our results are consistent with a mechanism for inactivation that is mediated through voltage-dependent conformations of the inner pore helix and allosteric coupling with the C-terminal extracellular domain.

  20. REPRODUCTIVE TOXICITY OF PHTHALATE ESTERS

    Science.gov (United States)

    Phthalate esters display several modes of toxicity in mammalian species. In the rat, in utero exposure at relatively low dosage levels disrupts development of the reproductive system of the male rat by altering fetal testis hormone production. This presentation is a review of t...

  1. Regioselective Synthesis of Cellulose Ester Homopolymers

    Science.gov (United States)

    Daiqiang Xu; Kristen Voiges; Thomas Elder; Petra Mischnick; Kevin J. Edgar

    2012-01-01

    Regioselective synthesis of cellulose esters is extremely difficult due to the small reactivity differences between cellulose hydroxyl groups, small differences in steric demand between acyl moieties of interest, and the difficulty of attaching and detaching many protecting groups in the presence of cellulose ester moieties without removing the ester groups. Yet the...

  2. Microbial synthesis of a branched-chain ester platform from organic waste carboxylates

    Directory of Open Access Journals (Sweden)

    Donovan S. Layton

    2016-12-01

    Full Text Available Processing of lignocellulosic biomass or organic wastes produces a plethora of chemicals such as short, linear carboxylic acids, known as carboxylates, derived from anaerobic digestion. While these carboxylates have low values and are inhibitory to microbes during fermentation, they can be biologically upgraded to high-value products. In this study, we expanded our general framework for biological upgrading of carboxylates to branched-chain esters by using three highly active alcohol acyltransferases (AATs for alcohol and acyl CoA condensation and modulating the alcohol moiety from ethanol to isobutanol in the modular chassis cell. With this framework, we demonstrated the production of an ester library comprised of 16 out of all 18 potential esters, including acetate, propionate, butanoate, pentanoate, and hexanoate esters, from the 5 linear, saturated C2-C6 carboxylic acids. Among these esters, 5 new branched-chain esters, including isobutyl acetate, isobutyl propionate, isobutyl butyrate, isobutyl pentanoate, and isobutyl hexanoate were synthesized in vivo. During 24 h in situ fermentation and extraction, one of the engineered strains, EcDL208 harnessing the SAAT of Fragaria ananassa produced ~63 mg/L of a mixture of butyl and isobutyl butyrates from glucose and butyrate co-fermentation and ~127 mg/L of a mixture of isobutyl and pentyl pentanoates from glucose and pentanoate co-fermentation, with high specificity. These butyrate and pentanoate esters are potential drop-in liquid fuels. This study provides better understanding of functional roles of AATs for microbial biosynthesis of branched-chain esters and expands the potential use of these esters as drop-in biofuels beyond their conventional flavor, fragrance, and solvent applications. Keywords: Carboxylate platform, Ester platform, Branched-chain ester, Modular cell, Biological upgrading, Organic waste, Lignocellulosic biomass, Isobutyl esters

  3. Furin is a chemokine-modifying enzyme: in vitro and in vivo processing of CXCL10 generates a C-terminally truncated chemokine retaining full activity.

    Science.gov (United States)

    Hensbergen, Paul J; Verzijl, Dennis; Balog, Crina I A; Dijkman, Remco; van der Schors, Roel C; van der Raaij-Helmer, Elizabeth M H; van der Plas, Mariena J A; Leurs, Rob; Deelder, André M; Smit, Martine J; Tensen, Cornelis P

    2004-04-02

    Chemokines comprise a class of structurally related proteins that are involved in many aspects of leukocyte migration under basal and inflammatory conditions. In addition to the large number of genes, limited processing of these proteins by a variety of enzymes enhances the complexity of the total spectrum of chemokine variants. We have recently shown that the native chemokine CXCL10 is processed at the C terminus, thereby shedding the last four amino acids. The present study was performed to elucidate the mechanism in vivo and in vitro and to study the biological activity of this novel isoform of CXCL10. Using a combination of protein purification and mass spectrometric techniques, we show that the production of C-terminally truncated CXCL10 by primary keratinocytes is inhibited in vivo by a specific inhibitor of pro-protein convertases (e.g. furin) but not by inhibition of matrix metalloproteinases. Moreover, CXCL10 is processed by furin in vitro, which is abrogated by a mutation in the furin recognition site. Using GTPgammaS binding, Ca(2+) mobilization, and chemotaxis assays, we demonstrate that the C-terminally truncated CXCL10 variant is a potent ligand for CXCR3. Moreover, the inverse agonist activity on the virally encoded receptor ORF74 and the direct antibacterial activity of CXCL10 are fully retained. Hence, we have identified furin as a novel chemokine-modifying enzyme in vitro and most probably also in vivo, generating a C-terminally truncated CXCL10, which fully retains its (inverse) agonistic properties.

  4. Fully convergent chemical synthesis of ester insulin: determination of the high resolution X-ray structure by racemic protein crystallography.

    Science.gov (United States)

    Avital-Shmilovici, Michal; Mandal, Kalyaneswar; Gates, Zachary P; Phillips, Nelson B; Weiss, Michael A; Kent, Stephen B H

    2013-02-27

    Efficient total synthesis of insulin is important to enable the application of medicinal chemistry to the optimization of the properties of this important protein molecule. Recently we described "ester insulin"--a novel form of insulin in which the function of the 35 residue C-peptide of proinsulin is replaced by a single covalent bond--as a key intermediate for the efficient total synthesis of insulin. Here we describe a fully convergent synthetic route to the ester insulin molecule from three unprotected peptide segments of approximately equal size. The synthetic ester insulin polypeptide chain folded much more rapidly than proinsulin, and at physiological pH. Both the D-protein and L-protein enantiomers of monomeric DKP ester insulin (i.e., [Asp(B10), Lys(B28), Pro(B29)]ester insulin) were prepared by total chemical synthesis. The atomic structure of the synthetic ester insulin molecule was determined by racemic protein X-ray crystallography to a resolution of 1.6 Å. Diffraction quality crystals were readily obtained from the racemic mixture of {D-DKP ester insulin + L-DKP ester insulin}, whereas crystals were not obtained from the L-ester insulin alone even after extensive trials. Both the D-protein and L-protein enantiomers of monomeric DKP ester insulin were assayed for receptor binding and in diabetic rats, before and after conversion by saponification to the corresponding DKP insulin enantiomers. L-DKP ester insulin bound weakly to the insulin receptor, while synthetic L-DKP insulin derived from the L-DKP ester insulin intermediate was fully active in binding to the insulin receptor. The D- and L-DKP ester insulins and D-DKP insulin were inactive in lowering blood glucose in diabetic rats, while synthetic L-DKP insulin was fully active in this biological assay. The structural basis of the lack of biological activity of ester insulin is discussed.

  5. Catalytic Ester to Stannane Functional Group Interconversion via Decarbonylative Cross-Coupling of Methyl Esters

    KAUST Repository

    Yue, Huifeng

    2018-01-03

    An unprecedented conversion of methyl esters to stannanes was realized, providing access to a series of arylstannanes via nickel catalysis. Various common esters including ethyl, cyclohexyl, benzyl, and phenyl esters can undergo the newly developed decarbonylative stannylation reaction. The reaction shows broad substrate scope, can differentiate between different types of esters, and if applied in consecutive fashion, allows the transformation of methyl esters into aryl fluorides or biaryls via fluororination or arylation.

  6. Catalytic Ester to Stannane Functional Group Interconversion via Decarbonylative Cross-Coupling of Methyl Esters

    KAUST Repository

    Yue, Huifeng; Zhu, Chen; Rueping, Magnus

    2018-01-01

    An unprecedented conversion of methyl esters to stannanes was realized, providing access to a series of arylstannanes via nickel catalysis. Various common esters including ethyl, cyclohexyl, benzyl, and phenyl esters can undergo the newly developed decarbonylative stannylation reaction. The reaction shows broad substrate scope, can differentiate between different types of esters, and if applied in consecutive fashion, allows the transformation of methyl esters into aryl fluorides or biaryls via fluororination or arylation.

  7. Optimization of the fermentation conditions and substrate specifity of mycelium-bound ester hydrolases of Aspergillus oryzae Cs007

    Directory of Open Access Journals (Sweden)

    de Hong Yan

    2015-01-01

    Full Text Available In order to improve mycelium-bound ester hydrolases activities of Aspergillus oryzae Cs007, the main production conditions were investigated. The ester hydrolases activities were simultaneously determined by titration assay and spectrophotometric assay methods, using olive oil and p-nitrophenyl esters as substrates, respectively. The optimum carbon source and nitrogen source were olive oil and peptone, with the concentrations of 1% and 2.2%, respectively. The effects of carbon source, nitrogen source and their concentrations on the production of enzymes were identical when the enzymes activities were assayed by the two methods. The mycelium-bound enzymes showed hydrolytic activity toward all the tested p-nitrophenyl esters, triglycerides and fatty acid ethyl esters. But it showed greater preference for long-chain triglycerides and short-chain p-nitrophenyl esters.

  8. Terminal ballistics

    CERN Document Server

    Rosenberg, Zvi

    2016-01-01

    This book comprehensively discusses essential aspects of terminal ballistics, combining experimental data, numerical simulations and analytical modeling. Employing a unique approach to numerical simulations as a measure of sensitivity for the major physical parameters, the new edition also includes the following features: new figures to better illustrate the problems discussed; improved explanations for the equation of state of a solid and for the cavity expansion process; new data concerning the Kolsky bar test; and a discussion of analytical modeling for the hole diameter in a thin metallic plate impacted by a shaped charge jet. The section on thick concrete targets penetrated by rigid projectiles has now been expanded to include the latest findings, and two new sections have been added: one on a novel approach to the perforation of thin concrete slabs, and one on testing the failure of thin metallic plates using a hydrodynamic ram.

  9. Three new fatty acid esters from the mushroom Boletus pseudocalopus.

    Science.gov (United States)

    Kim, Ki Hyun; Choi, Sang Un; Lee, Kang Ro

    2012-06-01

    A bioassay-guided fractionation and chemical investigation of a MeOH extract of the Korean wild mushroom Boletus pseudocalopus resulted in the identification of three new fatty acid esters, named calopusins A-C (1-3), along with two known fatty acid methyl esters (4-5). These new compounds are structurally unique fatty acid esters with a 2,3-butanediol moiety. Their structures were elucidated through 1D- and 2D-NMR spectroscopic data and GC-MS analysis as well as a modified Mosher's method. The new compounds 1-3 showed significant inhibitory activity against the proliferation of the tested cancer cell lines with IC(50) values in the range 2.77-12.51 μM.

  10. Chemical ablation of the Purkinje system causes early termination and activation rate slowing of long-duration ventricular fibrillation in dogs.

    Science.gov (United States)

    Dosdall, Derek J; Tabereaux, Paul B; Kim, Jong J; Walcott, Gregory P; Rogers, Jack M; Killingsworth, Cheryl R; Huang, Jian; Robertson, Peter G; Smith, William M; Ideker, Raymond E

    2008-08-01

    Endocardial mapping has suggested that Purkinje fibers may play a role in the maintenance of long-duration ventricular fibrillation (LDVF). To determine the influence of Purkinje fibers on LDVF, we chemically ablated the Purkinje system with Lugol solution and recorded endocardial and transmural activation during LDVF. Dog hearts were isolated and perfused, and the ventricular endocardium was exposed and treated with Lugol solution (n = 6) or normal Tyrode solution as a control (n = 6). The left anterior papillary muscle endocardium was mapped with a 504-electrode (21 x 24) plaque with electrodes spaced 1 mm apart. Transmural activation was recorded with a six-electrode plunge needle on each side of the plaque. Ventricular fibrillation (VF) was induced, and perfusion was halted. LDVF spontaneously terminated sooner in Lugol-ablated hearts than in control hearts (4.9 +/- 1.5 vs. 9.2 +/- 3.2 min, P = 0.01). After termination of VF, both the control and Lugol hearts were typically excitable, but only short episodes of VF could be reinduced. Endocardial activation rates were similar during the first 2 min of LDVF for Lugol-ablated and control hearts but were significantly slower in Lugol hearts by 3 min. In control hearts, the endocardium activated more rapidly than the epicardium after 4 min of LDVF with wave fronts propagating most often from the endocardium to epicardium. No difference in transmural activation rate or wave front direction was observed in Lugol hearts. Ablation of the subendocardium hastens VF spontaneous termination and alters VF activation sequences, suggesting that Purkinje fibers are important in the maintenance of LDVF.

  11. Fine tuning of the catalytic activity of colicin E7 nuclease domain by systematic N-terminal mutations

    Czech Academy of Sciences Publication Activity Database

    Németh, E.; Körtvélyesi, T.; Thulstrup, P. W.; Christensen, H. E. M.; Kožíšek, Milan; Nagata, K.; Czene, A.; Gyurcsik, B.

    2014-01-01

    Roč. 23, č. 8 (2014), s. 1113-1122 ISSN 0961-8368 Grant - others:Seventh Framework Programme of the European Union(XE) FP7-312284; OPPC(CZ) CZ.2.16/3.1.00/24016 Institutional support: RVO:61388963 Keywords : DNA cleavage * flow linear dichroism * isothermal calorimetry * positively charged N-terminal residues * Zn2+ binding Subject RIV: CE - Biochemistry Impact factor: 2.854, year: 2014

  12. The C-terminal random coil region tunes the Ca²⁺-binding affinity of S100A4 through conformational activation.

    Directory of Open Access Journals (Sweden)

    Annette Duelli

    Full Text Available S100A4 interacts with many binding partners upon Ca2+ activation and is strongly associated with increased metastasis formation. In order to understand the role of the C-terminal random coil for the protein function we examined how small angle X-ray scattering of the wild-type S100A4 and its C-terminal deletion mutant (residues 1-88, Δ13 changes upon Ca2+ binding. We found that the scattering intensity of wild-type S100A4 changes substantially in the 0.15-0.25 Å-1 q-range whereas a similar change is not visible in the C-terminus deleted mutant. Ensemble optimization SAXS modeling indicates that the entire C-terminus is extended when Ca2+ is bound. Pulsed field gradient NMR measurements provide further support as the hydrodynamic radius in the wild-type protein increases upon Ca2+ binding while the radius of Δ13 mutant does not change. Molecular dynamics simulations provide a rational explanation of the structural transition: the positively charged C-terminal residues associate with the negatively charged residues of the Ca2+-free EF-hands and these interactions loosen up considerably upon Ca2+-binding. As a consequence the Δ13 mutant has increased Ca2+ affinity and is constantly loaded at Ca2+ concentration ranges typically present in cells. The activation of the entire C-terminal random coil may play a role in mediating interaction with selected partner proteins of S100A4.

  13. New phenolic esters from the resinous exudate of Haplopappus taeda.

    Science.gov (United States)

    Faini, Francesca; Labbé, Cecilia; Torres, René; Rodilla, Jesús M; Silva, Lucía; Delle Monache, Franco

    2007-12-01

    Two new phenolic esters 9-trans-p-coumaroyloxy-alpha-terpineol (1) and 7-trans-p-coumaroyloxy-taedol (2), both endowed with free radical scavenger activity and cleroda-3,13 (E)-dien-15,18-diol (3) for which a cis stereochemistry at the decalin junction was found, were isolated from the resinous exudate from Haplopappus taeda upper parts.

  14. Influence of insulin sensitivity and the TaqIB cholesteryl ester transfer protein gene polymorphism on plasma lecithin:cholesterol acyltransferase and lipid transfer protein activities and their response to hyperinsulinemia in non-diabetic men

    NARCIS (Netherlands)

    S.C. Riemens; A. van Tol (Arie); B.K. Stulp; R.P.F. Dullaart (Robin)

    1999-01-01

    textabstractLecithin:cholesteryl acyl transferase (LCAT), cholesteryl ester transfer protein (CETP), phospholipid transfer protein (PLTP), and lipoprotein lipases are involved in high density lipoprotein (HDL) metabolism. We evaluated the influence of insulin

  15. Stereoselective formation of a cholesterol ester conjugate from fenvalerate by mouse microsomal carboxyesterase(s).

    Science.gov (United States)

    Miyamoto, J; Kaneko, H; Takamatsu, Y

    1986-06-01

    In accordance with in vivo findings, of the four chiral isomers of fenvalerate (S-5602 Sumicidin, Pydrin, [RS]-alpha-cyano-3-phenoxybenzyl [RS]-2-(4-chlorophenyl)isovalerate), only the [2R, alpha S]-isomer (B-isomer) yielded cholesteryl [2R]-2-(4-chlorophenyl)isovalerate (CPIA-cholesterol ester) in the in vitro study using several tissue homogenates of mice, rats, dogs, and monkeys. There were species differences in the extent of CPIA-cholesterol-ester formation, with mouse tissues showing relatively higher activity than those of other animals. The kidney, brain, and spleen of mice showed relatively higher capacities to form this ester compared to other tissues, and the enzyme activity was mainly localized in microsomal fractions. The CPIA-cholesterol ester did not seem to be produced by three known biosynthetic pathways of endogenous cholesterol esters--acyl-CoA:cholesterol O-acyltransferase (ACAT), lecithin:cholesterol O-acyltransferase (LCAT), and cholesterol esterase. Carboxyesterase(s) of mouse kidney microsomes solubilized by digitonin hydrolyzed only the B alpha-isomer of fenvalerate, yielding CPIA, whereas they yielded the corresponding cholesterol ester in the presence of artificial liposomes containing cholesterol. Thus, it appears that the stereoselective formation of the CPIA-cholesterol ester results from the stereoselective formation of the CPIA-carboxyesterase complex only from the B alpha-isomer, which subsequently undergoes cleavage by cholesterol to yield the CPIA-cholesterol ester.

  16. c-Jun NH2-terminal kinase activity in subcutaneous adipose tissue but not nuclear factor-kappaB activity in peripheral blood mononuclear cells is an independent determinant of insulin resistance in healthy individuals

    DEFF Research Database (Denmark)

    Sourris, Karly C; Lyons, Jasmine G; de Courten, Maximilian

    2009-01-01

    Chronic low-grade activation of the immune system (CLAIS) predicts type 2 diabetes via a decrease in insulin sensitivity. Our study investigated potential relationships between nuclear factor-kappaB (NF-kappaB) and c-Jun NH(2)-terminal kinase (JNK) pathways-two pathways proposed as the link between...

  17. Synthesis of novel naphthoquinone aliphatic amides and esters and their anticancer evaluation.

    Science.gov (United States)

    Kongkathip, Boonsong; Akkarasamiyo, Sunisa; Hasitapan, Komkrit; Sittikul, Pichamon; Boonyalai, Nonlawat; Kongkathip, Ngampong

    2013-02-01

    Fourteen new naphthoquinone aliphatic amides and seventeen naphthoquinone aliphatic esters were synthesized in nine to ten steps from 1-hydroxy-2-naphthoic acid with 9-25% overall yield for the amides, and 16-21% overall yield for the esters. The key step of the amide synthesis is a coupling reaction between amine and various aliphatic acids using 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMTMM) as a coupling agent while for the ester synthesis, DCC/DMAP or CDI was used as the coupling reagent between aliphatic acids and naphthoquinone alcohol. Both naphthoquinone amides and esters were evaluated for their anticancer activity against KB cells. It was found that naphthoquinone aliphatic amides showed stronger anticancer activity than those of the esters when the chains are longer than 7-carbon atoms. The optimum chain of amides is expected to be 16-carbon atoms. In addition, naphthoquinone aliphatic esters with α-methyl on the ester moiety possessed much stronger anticancer activity than the straight chains. Decatenation assay revealed that naphthoquinone amide with 16-carbon atoms chain at 15 μM and 20 μM can completely inhibit hTopoIIα activity while at 10 μM the enzyme activity was moderately inhibited. Molecular docking result also showed the same trend as the cytotoxicity and decatenation assay. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  18. Termination unit

    Science.gov (United States)

    Traeholt, Chresten [Frederiksberg, DK; Willen, Dag [Klagshamn, SE; Roden, Mark [Newnan, GA; Tolbert, Jerry C [Carrollton, GA; Lindsay, David [Carrollton, GA; Fisher, Paul W [Heiskell, TN; Nielsen, Carsten Thidemann [Jaegerspris, DK

    2014-01-07

    This invention relates to a termination unit comprising an end-section of a cable. The end section of the cable defines a central longitudinal axis and comprising end-parts of N electrical phases, an end-part of a neutral conductor and a surrounding thermally insulation envelope adapted to comprising a cooling fluid. The end-parts of the N electrical phases and the end-part of the neutral conductor each comprising at least one electrical conductor and being arranged in the cable concentrically around a core former with a phase 1 located relatively innermost, and phase N relatively outermost in the cable, phase N being surrounded by the neutral conductor, electrical insulation being arrange between neighboring electrical phases and between phase N and the neutral conductor, and wherein the end-parts of the neutral conductor and the electrical phases each comprise a contacting surface electrically connected to at least one branch current lead to provide an electrical connection: The contacting surfaces each having a longitudinal extension, and being located sequentially along the longitudinal extension of the end-section of the cable. The branch current leads being individually insulated from said thermally insulation envelope by individual electrical insulators.

  19. C-Terminally modified peptides via cleavage of the HMBA linker by O-, N- or S-nucleophiles

    DEFF Research Database (Denmark)

    Hansen, Jonas; Diness, Frederik; Meldal, Morten Peter

    2016-01-01

    A large variety of C-terminally modified peptides was obtained by nucleophilic cleavage of the ester bond in solid phase linked peptide esters of 4-hydroxymethyl benzamide (HMBA). The developed methods provided peptides, C-terminally functionalized as esters, amides and thioesters, with high purity...... directly from the resin in a single reaction step. A comprehensive screening of the reaction conditions and scope for nucleophilic cleavage of peptides from the HMBA linker was performed....

  20. Inhibitory effects of curcumin and capsaicin on phorbol ester-induced activation of eukaryotic transcription factors, NF-kappaB and AP-1.

    Science.gov (United States)

    Surh, Y J; Han, S S; Keum, Y S; Seo, H J; Lee, S S

    2000-01-01

    Recently, considerable attention has been focused on identifying dietary and medicinal phytochemicals that can inhibit, retard or reverse the multi-stage carcinogenesis. Spices and herbs contain phenolic substances with potent antioxidative and chemopreventive properties. Curcumin, a yellow colouring agent from turmeric and capsaicin, a pungent principle of red pepper exhibit profound anticarcinogenic and antimutagenic activities. Two well-defined eukaryotic transcription factors, nuclear factor-kappa B (NF-kappaB) and activator protein 1 (AP-1) have been implicated in pathogenesis of many human diseases including cancer. These transcription factors are known to be activated by a wide array of external stimuli, such as tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA), tumor necrosis factor, reactive oxygen species, bacterial lipopolysaccharide, and ultraviolet. In the present study, we found that topical application of TPA onto dorsal skin of female ICR mice resulted in marked activation of epidermal NF-kappaB and AP-1. Curcumin and capsaicin, when topically applied prior to TPA, significantly attenuated TPA-induced activation of each transcription factor in mouse skin. Likewise, both compounds inhibited NF-kappaB and AP-1 activation in cultured human promyelocytic leukemia (HL-60) cells stimulated with TPA. Based on these findings, it is likely that curcumin and capsaicin exert anti-tumor promotional effects through suppression of the tumor promoter-induced activation of transcription factors, NF-kappaB and AP-1.

  1. Activation of the plasma membrane Na/H antiporter salt-overly-sensitive 1 (SOS1) by phosphorylation of an auto-inhibitory C-terminal domain

    KAUST Repository

    Quintero, Francisco J.; Martí nez-Atienza, Juliana; Villalta, Irene; Jiang, Xingyu; Kim, Woeyeon; Ali, Zhair; Fujii, Hiroaki; Mendoza, Imelda; Yun, Daejin; Zhu, Jian-Kang; Pardo, José Manuel

    2011-01-01

    The plasma membrane sodium/proton exchanger Salt-Overly-Sensitive 1 (SOS1) is a critical salt tolerance determinant in plants. The SOS2-SOS3 calcium-dependent protein kinase complex upregulates SOS1 activity, but the mechanistic details of this crucial event remain unresolved. Here we show that SOS1 is maintained in a resting state by a C-terminal auto-inhibitory domain that is the target of SOS2-SOS3. The auto-inhibitory domain interacts intramolecularly with an adjacent domain of SOS1 that is essential for activity. SOS1 is relieved from auto-inhibition upon phosphorylation of the auto-inhibitory domain by SOS2-SOS3. Mutation of the SOS2 phosphorylation and recognition site impeded the activation of SOS1 in vivo and in vitro. Additional amino acid residues critically important for SOS1 activity and regulation were identified in a genetic screen for hypermorphic alleles.

  2. Activation of the plasma membrane Na/H antiporter salt-overly-sensitive 1 (SOS1) by phosphorylation of an auto-inhibitory C-terminal domain

    KAUST Repository

    Quintero, Francisco J.

    2011-01-24

    The plasma membrane sodium/proton exchanger Salt-Overly-Sensitive 1 (SOS1) is a critical salt tolerance determinant in plants. The SOS2-SOS3 calcium-dependent protein kinase complex upregulates SOS1 activity, but the mechanistic details of this crucial event remain unresolved. Here we show that SOS1 is maintained in a resting state by a C-terminal auto-inhibitory domain that is the target of SOS2-SOS3. The auto-inhibitory domain interacts intramolecularly with an adjacent domain of SOS1 that is essential for activity. SOS1 is relieved from auto-inhibition upon phosphorylation of the auto-inhibitory domain by SOS2-SOS3. Mutation of the SOS2 phosphorylation and recognition site impeded the activation of SOS1 in vivo and in vitro. Additional amino acid residues critically important for SOS1 activity and regulation were identified in a genetic screen for hypermorphic alleles.

  3. Genistein inhibits phorbol ester-induced NF-κB transcriptional activity and COX-2 expression by blocking the phosphorylation of p65/RelA in human mammary epithelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Myung-Hoon; Kim, Do-Hee [Research Institute for Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul (Korea, Republic of); Na, Hye-Kyung [Department of Food and Nutrition, Sungshin Women' s University, Seoul (Korea, Republic of); Kim, Jung-Hwan; Kim, Ha-Na [Research Institute for Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul (Korea, Republic of); Haegeman, Guy [LEGEST, University of Gent (Belgium); Surh, Young-Joon, E-mail: surh@snu.ac.kr [Research Institute for Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul (Korea, Republic of); Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul (Korea, Republic of); Cancer Research Institute, Seoul National University, Seoul (Korea, Republic of)

    2014-10-15

    Genistein, an isoflavone present in soy products, has chemopreventive effects on mammary carcinogenesis. In the present study, we have investigated the effects of genistein on phorbol ester-induced expression of cyclooxygenase-2 (COX-2) that plays an important role in the pathophysiology of inflammation-associated carcinogenesis. Pretreatment of cultured human breast epithelial (MCF10A) cells with genistein reduced COX-2 expression induced by 12-O-tetradecanoylphorbol-13-acetate (TPA). There are multiple lines of evidence supporting that the induction of COX-2 is regulated by the eukaryotic transcription factor NF-κB. Genistein failed to inhibit TPA-induced nuclear translocation and DNA binding of NF-κB as well as degradation of IκB. However, genistein abrogated the TPA-induced transcriptional activity of NF-κB as determined by the luciferase reporter gene assay. Genistein inhibited phosphorylation of the p65 subunit of NF-κB and its interaction with cAMP regulatory element-binding protein-binding protein (CBP)/p300 and TATA-binding protein (TBP). TPA-induced NF-κB phosphorylation was abolished by pharmacological inhibition of extracellular signal-regulated kinase (ERK). Likewise, pharmacologic inhibition or dominant negative mutation of ERK suppressed phosphorylation of p65. The above findings, taken together, suggest that genistein inhibits TPA-induced COX-2 expression in MCF10A cells by blocking ERK-mediated phosphorylation of p65 and its subsequent interaction with CBP and TBP.

  4. ANALYSIS ON BILLING SYSTEM IMPLEMENTATION QUALITY IN ENDEAVOR TO INCREASE CUSTOMER SATISFACTION IN IMPORT ACTIVITY: STUDY OF SURABAYA CONTAINER TERMINAL

    Directory of Open Access Journals (Sweden)

    Dzulkirom M.

    2017-10-01

    Full Text Available This study aims to determine and explain the simultaneous and partial effects of service quality components consisting of reliability, responsiveness, assurance to customer satisfaction in PT. Terminal Petikemas Surabaya, аnd to know аnd explаin which between the three service quаlity vаriаbles thаt hаve а dominаnt effect on customer sаtisfаction. The type of reseаrch used is explаnаtory reseаrch with populаtion or census method with quаntitаtive аpproаch. Sаmples taken were 35 Billing Service users registered in PT. Terminal Petikemas Surabaya. Dаtа collection method used is questionnаire. The result of multiple lineаr regression аnаlysis shows thаt the three independent vаriаbles reliability, responsiveness, аssurаnce hаve significаnt influence on the dependent vаriаble thаt is customer sаtisfаction.

  5. Influence of iron solubility and charged surface-active compounds on lipid oxidation in fatty acid ethyl esters containing association colloids.

    Science.gov (United States)

    Homma, Rika; Johnson, David R; McClements, D Julian; Decker, Eric A

    2016-05-15

    The impact of iron compounds with different solubilities on lipid oxidation was studied in the presence and absence of association colloids. Iron (III) sulfate only accelerated lipid oxidation in the presence of association colloids while iron (III) oleate accelerated oxidation in the presence and absence of association colloids. Further, iron (III) oxide retarded lipid oxidation both with and without association colloids. The impact of charged association colloids on lipid oxidation in ethyl oleate was also investigated. Association colloids consisting of the anionic surface-active compound dodecyl sulphosuccinate sodium salt (AOT), cationic surface-active compound hexadecyltrimethylammonium bromide (CTAB), and nonionic surface-active compound 4-(1,1,3,3-tetramethylbutyl)phenyl-polyethylene glycol (Triton X-100) retarded, promoted, and had no effect on lipid oxidation rates, respectively. These results indicate that the polarity of metal compounds and the charge of association colloids play a big role in lipid oxidation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Ester Tuiksoo. Proua Suhkru kibedad päevad / Ester Tuiksoo ; interv. Piret Tali

    Index Scriptorium Estoniae

    Tuiksoo, Ester, 1965-

    2005-01-01

    Põllumajandusminister Ester Tuiksoo, kellel peagi täitub ministri ametis aasta Euroopa Liidu suhkrutrahvist, maaettevõtlusest, põllumajandusest, Euroopa Liidu toetustest, ministri elu- ja teenistuskäigust. Lisa: Ester Tuiksoo

  7. Palliative options of last resort: a comparison of voluntarily stopping eating and drinking, terminal sedation, physician-assisted suicide, and voluntary active euthanasia.

    Science.gov (United States)

    Quill, T E; Lo, B; Brock, D W

    1997-12-17

    Palliative care is generally agreed to be the standard of care for the dying, but there remain some patients for whom intolerable suffering persists. In the face of ethical and legal controversy about the acceptability of physician-assisted suicide and voluntary active euthanasia, voluntarily stopping eating and drinking and terminal sedation have been proposed as ethically superior responses of last resort that do not require changes in professional standards or the law. The clinical and ethical differences and similarities between these 4 practices are critically compared in light of the doctrine of double effect, the active/passive distinction, patient voluntariness, proportionality between risks and benefits, and the physician's potential conflict of duties. Terminal sedation and voluntarily stopping eating and drinking would allow clinicians to remain responsive to a wide range of patient suffering, but they are ethically and clinically more complex and closer to physician-assisted suicide and voluntary active euthanasia than is ordinarily acknowledged. Safeguards are presented for any medical action that may hasten death, including determining that palliative care is ineffective, obtaining informed consent, ensuring diagnostic and prognostic clarity, obtaining an independent second opinion, and implementing reporting and monitoring processes. Explicit public policy about which of these practices are permissible would reassure the many patients who fear a bad death in their future and allow for a predictable response for the few whose suffering becomes intolerable in spite of optimal palliative care.

  8. Cp*Co(III) Catalyzed Site-Selective C-H Activation of Unsymmetrical O-Acyl Oximes: Synthesis of Multisubstituted Isoquinolines from Terminal and Internal Alkynes.

    Science.gov (United States)

    Sun, Bo; Yoshino, Tatsuhiko; Kanai, Motomu; Matsunaga, Shigeki

    2015-10-26

    The synthesis of isoquinolines by site-selective C-H activation of O-acyl oximes with a Cp*Co(III) catalyst is described. In the presence of this catalyst, the C-H activation of various unsymmetrically substituted O-acyl oximes selectively occurred at the sterically less hindered site, and reactions with terminal as well as internal alkynes afforded the corresponding products in up to 98 % yield. Whereas the reactions catalyzed by the Cp*Co(III) system proceeded with high site selectivity (15:1 to 20:1), use of the corresponding Cp*Rh(III) catalysts led to low selectivities and/or yields when unsymmetrical O-acyl oximes and terminal alkynes were used. Deuterium labeling studies indicate a clear difference in the site selectivity of the C-H activation step under Cp*Co(III) and Cp*Rh(III) catalysis. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. 4-alkyl-L-(Dehydro)proline biosynthesis in actinobacteria involves N-terminal nucleophile-hydrolase activity of γ-glutamyltranspeptidase homolog for C-C bond cleavage

    Science.gov (United States)

    Zhong, Guannan; Zhao, Qunfei; Zhang, Qinglin; Liu, Wen

    2017-07-01

    γ-Glutamyltranspeptidases (γ-GTs), ubiquitous in glutathione metabolism for γ-glutamyl transfer/hydrolysis, are N-terminal nucleophile (Ntn)-hydrolase fold proteins that share an autoproteolytic process for self-activation. γ-GT homologues are widely present in Gram-positive actinobacteria where their Ntn-hydrolase activities, however, are not involved in glutathione metabolism. Herein, we demonstrate that the formation of 4-Alkyl-L-(dehydro)proline (ALDP) residues, the non-proteinogenic α-amino acids that serve as vital components of many bioactive metabolites found in actinobacteria, involves unprecedented Ntn-hydrolase activity of γ-GT homologue for C-C bond cleavage. The related enzymes share a key Thr residue, which acts as an internal nucleophile for protein hydrolysis and then as a newly released N-terminal nucleophile for carboxylate side-chain processing likely through the generation of an oxalyl-Thr enzyme intermediate. These findings provide mechanistic insights into the biosynthesis of various ALDP residues/associated natural products, highlight the versatile functions of Ntn-hydrolase fold proteins, and particularly generate interest in thus far less-appreciated γ-GT homologues in actinobacteria.

  10. [The importance of C-terminal aspartic acid residue (D141) to the antirestriction activity of the ArdB (R64) protein].

    Science.gov (United States)

    Kudryavtseva, A A; Osetrova, M S; Livinyuk, V Ya; Manukhov, I V; Zavilgelsky, G B

    2017-01-01

    Antirestriction proteins of the ArdB/KlcA family are specific inhibitors of restriction (endonuclease) activity of type-I restriction/modification enzymes. The effect of conserved amino acid residues on the antirestriction activity of the ArdB protein encoded by the transmissible R64 (IncI1) plasmid has been investigated. An analysis of the amino acid sequences of ArdB homologues demonstrated the presence of four groups of conserved residues ((1) R16, E32, and W51; (2) Y46 and G48; (3) S81, D83 and E132, and (4) N77, L(I)140, and D141) on the surface of the protein globule. Amino acid residues of the fourth group showed a unique localization pattern with the terminal residue protruding beyond the globule surface. The replacement of two conserved amino acids (D141 and N77) located in the close vicinity of each other on the globule surface showed that the C-terminal D141 is essential for the antirestriction activity of ArdB. The deletion of this residue, as well as replacement by a hydrophobic threonine residue (D141T), completely abolished the antirestriction activity of ArdB. The synonymous replacement of D141 by a glutamic acid residue (D141E) caused an approximately 30-fold decrease of the antirestriction activity of ArdB, and the point mutation N77A caused an approximately 20-fold decrease in activity. The residues D141 and N77 located on the surface of the protein globule are presumably essential for the formation of a contact between ArdB and a currently unknown factor that modulates the activity of type-I restriction/modification enzymes.

  11. Method of making a cyanate ester foam

    Science.gov (United States)

    Celina, Mathias C.; Giron, Nicholas Henry

    2014-08-05

    A cyanate ester resin mixture with at least one cyanate ester resin, an isocyanate foaming resin, other co-curatives such as polyol or epoxy compounds, a surfactant, and a catalyst/water can react to form a foaming resin that can be cured at a temperature greater than 50.degree. C. to form a cyanate ester foam. The cyanate ester foam can be heated to a temperature greater than 400.degree. C. in a non-oxidative atmosphere to provide a carbonaceous char foam.

  12. Pharmacological analysis of the activation and receptor properties of the tonic GABA(CR current in retinal bipolar cell terminals.

    Directory of Open Access Journals (Sweden)

    Stefanie M Jones

    Full Text Available GABAergic inhibition in the central nervous system (CNS can occur via rapid, transient postsynaptic currents and via a tonic increase in membrane conductance, mediated by synaptic and extrasynaptic GABA(A receptors (GABA(ARs respectively. Retinal bipolar cells (BCs exhibit a tonic current mediated by GABA(CRs in their axon terminal, in addition to synaptic GABA(AR and GABA(CR currents, which strongly regulate BC output. The tonic GABA(CR current in BC terminals (BCTs is not dependent on vesicular GABA release, but properties such as the alternative source of GABA and the identity of the GABA(CRs remain unknown. Following a recent report that tonic GABA release from cerebellar glial cells is mediated by Bestrophin 1 anion channels, we have investigated their role in non-vesicular GABA release in the retina. Using patch-clamp recordings from BCTs in goldfish retinal slices, we find that the tonic GABA(CR current is not reduced by the anion channel inhibitors NPPB or flufenamic acid but is reduced by DIDS, which decreases the tonic current without directly affecting GABA(CRs. All three drugs also exhibit non-specific effects including inhibition of GABA transporters. GABA(CR ρ subunits can form homomeric and heteromeric receptors that differ in their properties, but BC GABA(CRs are thought to be ρ1-ρ2 heteromers. To investigate whether GABA(CRs mediating tonic and synaptic currents may differ in their subunit composition, as is the case for GABA(ARs, we have examined the effects of two antagonists that show partial ρ subunit selectivity: picrotoxin and cyclothiazide. Tonic and synaptic GABA(CR currents were differentially affected by both drugs, suggesting that a population of homomeric ρ1 receptors contributes to the tonic current. These results extend our understanding of the multiple forms of GABAergic inhibition that exist in the CNS and contribute to visual signal processing in the retina.

  13. The C-terminal tail of CRTH2 is a key molecular determinant that constrains GalphaI- and downstream-signaling cascade activation

    DEFF Research Database (Denmark)

    Schroeder, Ralf; Merten, Nicole; Mathiesen, Jesper Mosolff

    2009-01-01

    Prostaglandin D(2) activation of the seven transmembrane receptor CRTH2 regulates numerous cell functions that are important in inflammatory diseases such as asthma. Despite its disease implication, no studies to date aimed at identifying receptor domains governing signaling and surface expression......2 at the plasma membrane, presence of this domain confers a signaling-compromised conformation onto the receptor. Indeed, a mutant receptor lacking the major portion of its C-terminal tail displays paradoxically enhanced Galphai and ERK1/2 activation in spite of enhanced constitutive and agonist......-mediated internalization. Enhanced activation of Galphai proteins and downstream signaling cascades is likely due to the inability of the tail-truncated receptor to recruit beta-arrestin2 and undergo homologous desensitization. Unexpectedly, CRTH2 is not phosphorylated upon agonist-stimulation, a primary mechanism...

  14. Structural characterization of saturated branched chain fatty acid methyl esters by collisional dissociation of molecular ions generated by electron ionization.

    Science.gov (United States)

    Ran-Ressler, Rinat R; Lawrence, Peter; Brenna, J Thomas

    2012-01-01

    Saturated branched chain fatty acids (BCFA) are present as complex mixtures in numerous biological samples. The traditional method for structure elucidation, electron ionization (EI) mass spectrometry, sometimes does not unambiguously enable assignment of branching in isomeric BCFA. Zirrolli and Murphy (Zirrolli , J. A. , and R. A. Murphy. 1993. Low-energy tandem mass spectrometry of the molecular ion derived from fatty acid methyl esters: a novel method for analysis of branched-chain fatty acids. J. Am. Soc. Mass Spectrom. 4: 223-229.) showed that the molecular ions of four BCFA methyl ester (BCFAME) yield highly characteristic fragments upon collisional dissociation using a triple quadrupole instrument. Here, we confirm and extend these results by analysis using a tabletop 3-D ion trap for activated molecular ion EI-MS/MS to 30 BCFAME. iso-BCFAME produces a prominent ion (30-100% of base peak) for [M-43] (M-C₃H₇), corresponding to the terminal isopropyl moiety in the original iso-BCFAME. Anteiso-FAME yield prominent ions (20-100% of base peak) corresponding to losses on both side of the methyl branch, [M-29] and [M-57], and tend to produce more prominent m/z 115 peaks corresponding to a cyclization product around the ester. Dimethyl and tetramethyl FAME, with branches separated by at least one methylene group, yield fragment on both sides of the sites of methyl branches that are more than 6 C away from the carboxyl carbon. EI-MS/MS yields uniquely specific ions that enable highly confident structural identification and quantification of BCFAME.

  15. New Insights on Degumming and Bleaching Process Parameters on The Formation of 3-Monochloropropane-1,2-Diol Esters and Glycidyl Esters in Refined, Bleached, Deodorized Palm Oil.

    Science.gov (United States)

    Sim, Biow Ing; Muhamad, Halimah; Lai, Oi Ming; Abas, Faridah; Yeoh, Chee Beng; Nehdi, Imededdine Arbi; Khor, Yih Phing; Tan, Chin Ping

    2018-04-01

    This paper examines the interactions of degumming and bleaching processes as well as their influences on the formation of 3-monochloropropane-1,2-diol esters (3-MCPDE) and glycidyl esters in refined, bleached and deodorized palm oil by using D-optimal design. Water degumming effectively reduced the 3-MCPDE content up to 50%. Acid activated bleaching earth had a greater effect on 3-MCPDE reduction compared to natural bleaching earth and acid activated bleaching earth with neutral pH, indicating that performance and adsorption capacities of bleaching earth are the predominant factors in the removal of esters, rather than its acidity profile. The combination of high dosage phosphoric acid during degumming with the use of acid activated bleaching earth eliminated almost all glycidyl esters during refining. Besides, the effects of crude palm oil quality was assessed and it was found that the quality of crude palm oil determines the level of formation of 3-MCPDE and glycidyl esters in palm oil during the high temperature deodorization step of physical refining process. Poor quality crude palm oil has strong impact towards 3-MCPDE and glycidyl esters formation due to the intrinsic components present within. The findings are useful to palm oil refining industry in choosing raw materials as an input during the refining process.

  16. In vitro antitumor activity, metal uptake and reactivity with ascorbic acid and BSA of some gold(III) complexes with N,N'-ethylenediamine bidentate ester ligands.

    Science.gov (United States)

    Pantelić, Nebojša; Zmejkovski, Bojana B; Kolundžija, Branka; Crnogorac, Marija Đorđić; Vujić, Jelena M; Dojčinović, Biljana; Trifunović, Srećko R; Stanojković, Tatjana P; Sabo, Tibor J; Kaluđerović, Goran N

    2017-07-01

    Four novel gold(III) complexes of general formulae [AuCl 2 {(S,S)-R 2 eddl}]PF 6 (R 2 eddl=O,O'-dialkyl-(S,S)-ethylenediamine-N,N'-di-2-(4-methyl)pentanoate, R=n-Pr, n-Bu, n-Pe, i-Bu; 1-4, respectively), were synthesized and characterized by elemental analysis, UV/Vis, IR, and NMR spectroscopy, as well as high resolution mass spectrometry. Density functional theory calculations pointed out that (R,R)-N,N'-configuration diastereoisomers were energetically the most favorable. Duo to high cytotoxic activity complex 3 was chosen for stability study in DMSO, no decomposition occurs within 24h, and for the reaction with ascorbic acid in which was reduced immediately. Additionally, 3 interacts with bovine serum albumin (BSA) as proven by UV/Vis spectroscopy. In vitro antitumor activity was determined against human cervix adenocarcinoma (HeLa), human myelogenous leukemia (K562), and human melanoma (Fem-x) cancer cell lines, as well as against non-cancerous human embryonic lung fibroblast cells MRC-5. The highest activity was observed against K562 cells (IC 50 : 5.04-6.51μM). Selectivity indices showed that these complexes are less toxic than cisplatin. 3 had a similar viability kinetics on HeLa cells as cisplatin. Drug accumulation studies in HeLa cells showed that the total gold uptake increased much faster than that of cisplatin pointing out that 3 more efficiently enters the cells than cisplatin. Furthermore, morphological and cell cycle analysis reveal that gold(III) complexes induced apoptosis in time- and dose-dependent manner. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Scandium Terminal Imido Chemistry.

    Science.gov (United States)

    Lu, Erli; Chu, Jiaxiang; Chen, Yaofeng

    2018-02-20

    of two p-d π bonds between the scandium ion and the nitrogen atom of the imido ligand and showed that the dianionic [NR] 2- imido ligand acts as a 2σ,4π electron donor. Subsequent studies of the scandium terminal imides revealed highly versatile and intriguing reactivity of the Sc═N bond. This included cycloaddition toward various unsaturated bonds, C-H/Si-H/B-H bond activations and catalytic hydrosilylation, dehydrofluorination of fluoro-substituted benzenes/alkanes, CO 2 and H 2 activations, activation of elemental selenium, coordination with other transition metal halides, etc. Since our initial success in 2010, and with contributions from us and across the community, this young, vibrant research field has rapidly flourished into one of the most active frontiers of rare-earth metal chemistry. The prospect of extending Ln═N chemistry to other rare-earth metals and/or different metal oxidation states, as well as exploiting their stoichiometric and catalytic reactivities, continues to attract research effort. Herein we present an account of our investigations into scandium terminal imido chemistry as a timely summary, in the hope that our studies will be of interest to this readership.

  18. N-terminal prodomain of Pfs230 synthesized using a cell-free system is sufficient to induce complement-dependent malaria transmission-blocking activity.

    Science.gov (United States)

    Tachibana, Mayumi; Wu, Yimin; Iriko, Hideyuki; Muratova, Olga; MacDonald, Nicholas J; Sattabongkot, Jetsumon; Takeo, Satoru; Otsuki, Hitoshi; Torii, Motomi; Tsuboi, Takafumi

    2011-08-01

    The aim of a malaria transmission-blocking vaccine is to block the development of malaria parasites in the mosquito and thus prevent subsequent infection of the human host. Previous studies have demonstrated that the gametocyte/gamete surface protein Pfs230 can induce transmission-blocking immunity and have evaluated Escherichia coli-produced Pfs230 as a transmission-blocking vaccine candidate. In this study, we used the wheat germ cell-free expression system to produce N-terminal fragments of Pfs230 and evaluated the transmission-blocking activity of antisera raised against the recombinant Pfs230 protein. The rabbit antisera reacted to the surface of cultured gametocytes and gametes of the Plasmodium falciparum NF54 line, recognized the 360-kDa form of parasite-produced Pfs230 by Western blot assay, and reduced the infectivity of NF54 parasites to Anopheles stefensi mosquitoes in the presence of complement in a standard membrane feeding assay. Thus, our data demonstrate that the N-terminal pro domain of Pfs230 is sufficient to induce complement-dependent transmission-blocking activity against P. falciparum.

  19. Standardization process for pipeline right-of-way activities: the case of TRANSPETRO's Oil Pipeline and Terminals Business Unit

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Kassandra Senra de Morais M.; Goncalves, Bruno Martins [TRANSPETRO - PETROBRAS Transporte S.A., Rio de Janeiro, RJ (Brazil). Diretoria de Terminais e Oleodutos; Almeida, Maria Fatima Ludovico de [Pontificia Universidade Catolica do Rio de Janeiro (PUC-Rio/ITUC), Rio de Janeiro, RJ (Brazil). Instituto Tecnologico

    2009-07-01

    This paper describes the experience of PETROBRAS Transporte S.A. concerning the standardization process for its pipeline right-of-way (ROW) activities. This standardization initiative has been carried out within the Oil Pipelines and Terminals Standardization Program (PRONOT), focusing on planning, standardization and implementation of all norms and corporate procedures referring to TRANSPETRO's right-of-way activities. The process promoted the integration of isolated regional initiatives, a sense of unity and the creation of a learning network consisting of 60 employees. This paper presents the last phase's results concerning implementation of corporate standards, based upon achievements of previous phases. It covers the following topics: a general view of the whole process by way of introduction; the potential of integration of recent standardization results with TRANSPETRO's corporate management tools and information systems; definition of four performance indicators and their metrics related to pipeline right-of-way management, as well as a corporate standard for the requirements for contracting services related to rights-of-way inspection, maintenance and communication; challenges, barriers and benefits perceived by the team responsible for formulating and implementing standards and procedures in TRANSPETRO's Oil Pipelines and Terminals Unit. (author)

  20. Improvement of Fructanohydrolase Production in Aspergillus niger SL-09 by Sucrose Ester

    Directory of Open Access Journals (Sweden)

    Xiang-Yang Ge

    2006-01-01

    Full Text Available The influence of carbon sources, nitrogen sources, and the addition of sucrose ester on fructanohydrolase production was investigated. The enzyme production varied depending on the carbon source. Apart from that, it was found that the enzyme activities formed by Aspergillus niger SL-09 were enhanced dramatically by the addition of sucrose ester S-770 to the medium. The effect of sucrose ester on enzyme production was also studied on molecular level, and it was confirmed that the transcription was activated by the addition of sucrose ester to the medium. The response surface methodology (RSM was used to optimize the composition for the production of fructanohydrolase, and the enzyme activities were enhanced more than 7-fold than those obtained in the basal medium.

  1. Cell-induced potentiation of the plasminogen activation system is abolished by a monoclonal antibody that recognizes the NH2-terminal domain of the urokinase receptor

    DEFF Research Database (Denmark)

    Rønne, E; Behrendt, N; Ellis, V

    1991-01-01

    We have raised four monoclonal antibodies recognizing different epitopes within the human cell-surface receptor for urokinase-type plasminogen activator (u-PA). One of these antibodies completely abolishes the potentiation of plasmin generation observed upon incubation of the zymogens pro......-u-PA and plasminogen with U937 cells. This antibody, which is also the only one to completely inhibit the binding of DFP-inactivated [125I]-u-PA to U937 cells, is directed against the u-PA binding NH2-terminal domain of u-PAR, a well-defined fragment formed by limited chymotrypsin digestion of purified u......-PAR, demonstrating the functional independence of the u-PA binding domain as well as the critical role of u-PAR in the assembly of the cell-surface plasminogen activation system....

  2. Structure-activity correlations for interactions of bicyclophosphorus esters and some polychlorocycloalkane and pyrethroid insecticides with the brain-specific t-butylbicyclophosphorothionate receptor

    International Nuclear Information System (INIS)

    Casida, J.E.; Lawrence, L.J.

    1985-01-01

    [ 35 S]t-Butylbicyclophosphorothionate or [ 35 S]TBPS is an improved radioligand for the picrotoxinin binding site in rat brain synaptic membranes. The toxic isomers of the hexachlorocyclohexanes, polychlorobornanes, and chlorinated cyclodienes displace [ 35 S]TBPS with a stereospecificity and potency generally correlated with their mammalian toxicity. In a few cases this correlation is improved by correction for metabolic activation or detoxification on using a coupled brain receptor/liver microsomal oxidase system. The alpha-cyano-3-phenoxybenzyl pyrethroids, although less potent, inhibit [ 35 S]TBPS binding in a stereospecific manner correlated with their toxicity. Scatchard analyses indicate that these three classes of polychlorocycloalkane insecticides act at the TBPS binding site within the gamma-aminobutyric acid (GABA) receptor-ionophore complex whereas the alpha-cyano pyrethroids interact with a closely associated site. These insecticides and TBPS analogs may serve as useful probes further to elucidate the topography of the TBPS binding site and its relationship to the chloride channel. 46 references

  3. Preparation of Spirocyclic β-Proline Esters

    DEFF Research Database (Denmark)

    Fjelbye, Kasper; Marigo, Mauro; Clausen, Rasmus Prætorius

    2017-01-01

    A series of novel N-Bn-protected spirocyclic β-proline esters were prepared using [3+2] cycloaddition and subsequently converted into their corresponding aldehydes. In addition, two novel N-Cbz-protected spirocyclic β-proline esters were prepared using intramolecular cyclization starting from...

  4. Dissociation Behavior of a TEMPO-Active Ester Cross-Linker for Peptide Structure Analysis by Free Radical Initiated Peptide Sequencing (FRIPS) in Negative ESI-MS.

    Science.gov (United States)

    Hage, Christoph; Ihling, Christian H; Götze, Michael; Schäfer, Mathias; Sinz, Andrea

    2017-01-01

    We have synthesized a homobifunctional amine-reactive cross-linking reagent, containing a TEMPO (2,2,6,6-tetramethylpiperidine-1-oxy) and a benzyl group (Bz), termed TEMPO-Bz-linker, to derive three-dimensional structural information of proteins. The aim for designing this novel cross-linker was to facilitate the mass spectrometric analysis of cross-linked products by free radical initiated peptide sequencing (FRIPS). In an initial study, we had investigated the fragmentation behavior of TEMPO-Bz-derivatized peptides upon collision activation in (+)-electrospray ionization collision-induced dissociation tandem mass spectrometry (ESI-CID-MS/MS) experiments. In addition to the homolytic NO-C bond cleavage FRIPS pathway delivering the desired odd-electron product ions, an alternative heterolytic NO-C bond cleavage, resulting in even-electron product ions mechanism was found to be relevant. The latter fragmentation route clearly depends on the protonation of the TEMPO-Bz-moiety itself, which motivated us to conduct (-)-ESI-MS, CID-MS/MS, and MS 3 experiments of TEMPO-Bz-cross-linked peptides to further clarify the fragmentation behavior of TEMPO-Bz-peptide molecular ions. We show that the TEMPO-Bz-linker is highly beneficial for conducting FRIPS in negative ionization mode as the desired homolytic cleavage of the NO-C bond is the major fragmentation pathway. Based on characteristic fragments, the isomeric amino acids leucine and isoleucine could be discriminated. Interestingly, we observed pronounced amino acid side chain losses in cross-linked peptides if the cross-linked peptides contain a high number of acidic amino acids. Graphical Abstract ᅟ.

  5. Stanol esters attenuate the aggravating effect of dietary cholesterol on atherosclerosis in homozygous Watanabe rabbits

    DEFF Research Database (Denmark)

    Schrøder, Malene; Husche, Constanze; Pilegaard, Kirsten

    2009-01-01

    Plant stanols are marketed as natural means to lower blood cholesterol in humans; hence the effect on combined familial hyperlipidemia is not known. The objective was to investigate the effect of stanol esters on blood lipids and aortic atherosclerosis in homozygous WHHL rabbits challenged...... with dietary cholesterol. A total of 36 rabbits, 6 weeks of age, with initial plasma cholesterol of 22.5 mmol/L were assigned to two treatment groups fed a standard rabbit chow with 1 g/kg cholesterol or this diet added 34 g/kg stanol ester, respectively, for 16 weeks. Plasma cholesterol was measured initially...... and at termination, also in lipoproteins. Aortic atherosclerosis was evaluated as cholesterol content and area covered by plaque. Plasma cholesterol was not significantly different between the groups at termination (35.7 mmol/L vs. 35.5 mmol/L). A significant increase in LDL was seen (13.1 mmol/L vs. 16.5 mmol...

  6. Voltage-sensing domain mode shift is coupled to the activation gate by the N-terminal tail of hERG channels.

    Science.gov (United States)

    Tan, Peter S; Perry, Matthew D; Ng, Chai Ann; Vandenberg, Jamie I; Hill, Adam P

    2012-09-01

    Human ether-a-go-go-related gene (hERG) potassium channels exhibit unique gating kinetics characterized by unusually slow activation and deactivation. The N terminus of the channel, which contains an amphipathic helix and an unstructured tail, has been shown to be involved in regulation of this slow deactivation. However, the mechanism of how this occurs and the connection between voltage-sensing domain (VSD) return and closing of the gate are unclear. To examine this relationship, we have used voltage-clamp fluorometry to simultaneously measure VSD motion and gate closure in N-terminally truncated constructs. We report that mode shifting of the hERG VSD results in a corresponding shift in the voltage-dependent equilibrium of channel closing and that at negative potentials, coupling of the mode-shifted VSD to the gate defines the rate of channel closure. Deletion of the first 25 aa from the N terminus of hERG does not alter mode shifting of the VSD but uncouples the shift from closure of the cytoplasmic gate. Based on these observations, we propose the N-terminal tail as an adaptor that couples voltage sensor return to gate closure to define slow deactivation gating in hERG channels. Furthermore, because the mode shift occurs on a time scale relevant to the cardiac action potential, we suggest a physiological role for this phenomenon in maximizing current flow through hERG channels during repolarization.

  7. The C'-terminal interaction domain of the thyroid hormone receptor confers the ability of the DNA site to dictate positive or negative transcriptional activity

    International Nuclear Information System (INIS)

    Holloway, J.M.; Glass, C.K.; Adler, S.; Nelson, C.A.; Rosenfeld, M.G.

    1990-01-01

    To investigate mechanisms responsible for positive and negative transcriptional control, the authors have utilized two types of promoters that are diffferentially regulated by thyroid hormone (T 3 ) receptors. Promoters containing the palindromic T 3 response element TCAGGTCA TGACCTGA are positively regulated by the T 3 receptor after the administration of T 3 , whereas otherwise identical promoters containing the estrogen response element TCAGGTCA CTG TGACCTGA can be regulated negatively; converse effects are observed with the estrogen receptor. They describe evidence that the transcriptional inhibitory effects of the T 3 or estrogen receptors on the estrogen or T 3 response elements, respectively, are imposed by amino acid sequences in the C'-terminal region that colocalize with dimerization and hormone-binding domains and that these sequences can transfer inhibitory functions to other classes of transcription factors. Removal of the C'-terminal dimerization and hormone-binding domains of either the αT 3 or estrogen receptors permits each receptor to act constitutively to enhance transcription on both T 3 and estrogen response elements. It is, therefore, suggested that protein-protein interactions between receptor C' termini limit the subset of DNA binding sites on which transcriptional activation occurs

  8. Transforming activity and therapeutic targeting of C-terminal-binding protein 2 in Apc-mutated neoplasia.

    Science.gov (United States)

    Sumner, E T; Chawla, A T; Cororaton, A D; Koblinski, J E; Kovi, R C; Love, I M; Szomju, B B; Korwar, S; Ellis, K C; Grossman, S R

    2017-08-17

    Overexpression of the transcriptional coregulators C-terminal binding proteins 1 and 2 (CtBP1 and 2) occurs in many human solid tumors and is associated with poor prognosis. CtBP modulates oncogenic gene expression programs and is an emerging drug target, but its oncogenic role is unclear. Consistent with this oncogenic potential, exogenous CtBP2 transformed primary mouse and human cells to anchorage independence similarly to mutant H-Ras. To investigate CtBP's contribution to in vivo tumorigenesis, Apc min/+ mice, which succumb to massive intestinal polyposis, were bred to Ctbp2 +/- mice. CtBP interacts with adenomatous polyposis coli (APC) protein, and is stabilized in both APC-mutated human colon cancers and Apc min/+ intestinal polyps. Ctbp2 heterozygosity increased the median survival of Apc min/+ mice from 21 to 48 weeks, and reduced polyp formation by 90%, with Ctbp2 +/- polyps exhibiting reduced levels of β-catenin and its oncogenic transcriptional target, cyclin D1. CtBP's potential as a therapeutic target was studied by treating Apc min/+ mice with the CtBP small-molecule inhibitors 4-methylthio-2-oxobutyric acid and 2-hydroxy-imino phenylpyruvic acid, both of which reduced polyposis by more than half compared with vehicle treatment. Phenocopying Ctbp2 deletion, both Ctbp inhibitors caused substantial decreases in the protein level of Ctbp2, as well its oncogenic partner β-catenin, and the effects of the inhibitors on CtBP and β-catenin levels could be modeled in an APC-mutated human colon cancer cell line. CtBP2 is thus a druggable transforming oncoprotein critical for the evolution of neoplasia driven by Apc mutation.

  9. Crystal Structure of Full-length Mycobacterium tuberculosis H37Rv Glycogen Branching Enzyme; Insights of N-Terminal [beta]-Sandwich in Sustrate Specifity and Enzymatic Activity

    Energy Technology Data Exchange (ETDEWEB)

    Pal, Kuntal; Kumar, Shiva; Sharma, Shikha; Garg, Saurabh Kumar; Alam, Mohammad Suhail; Xu, H. Eric; Agrawal, Pushpa; Swaminathan, Kunchithapadam (NU Sinapore); (Van Andel); (IMT-India)

    2010-07-13

    The open reading frame Rv1326c of Mycobacterium tuberculosis (Mtb) H37Rv encodes for an {alpha}-1,4-glucan branching enzyme (MtbGlgB, EC 2.4.1.18, Uniprot entry Q10625). This enzyme belongs to glycoside hydrolase (GH) family 13 and catalyzes the branching of a linear glucose chain during glycogenesis by cleaving a 1 {yields} 4 bond and making a new 1 {yields} 6 bond. Here, we show the crystal structure of full-length MtbGlgB (MtbGlgBWT) at 2.33-{angstrom} resolution. MtbGlgBWT contains four domains: N1 {beta}-sandwich, N2 {beta}-sandwich, a central ({beta}/{alpha}){sub 8} domain that houses the catalytic site, and a C-terminal {beta}-sandwich. We have assayed the amylase activity with amylose and starch as substrates and the glycogen branching activity using amylose as a substrate for MtbGlgBWT and the N1 domain-deleted (the first 108 residues deleted) Mtb{Delta}108GlgB protein. The N1 {beta}-sandwich, which is formed by the first 105 amino acids and superimposes well with the N2 {beta}-sandwich, is shown to have an influence in substrate binding in the amylase assay. Also, we have checked and shown that several GH13 family inhibitors are ineffective against MtbGlgBWT and Mtb{Delta}108GlgB. We propose a two-step reaction mechanism, for the amylase activity (1 {yields} 4 bond breakage) and isomerization (1 {yields} 6 bond formation), which occurs in the same catalytic pocket. The structural and functional properties of MtbGlgB and Mtb{Delta}108GlgB are compared with those of the N-terminal 112-amino acid-deleted Escherichia coli GlgB (EC{Delta}112GlgB).

  10. Investigations on the transport and metabolism of high density lipoprotein cholesteryl esters in African green monkeys

    International Nuclear Information System (INIS)

    Sorci-Thomas, M.G.

    1984-01-01

    The metabolic fate of circulating high density lipoprotein cholesteryl esters was studied in African green monkeys to determine the significance of the lipid transfer reaction on the catabolism of lipoprotein cholesteryl esters. A method of doubly labeling both moieties of lipoprotein cholesteryl esters with [ 3 He]cholesteryl oleate and cholesteryl [ 14 C]oleate was developed for the purpose of studying plasma cholesteryl ester metabolism in vivo. In these studies the total plasma [ 3 He]cholesterol turnover resulted in production rates, which ranged from 10-17 mg/kg day, similar to previously reported values in African green monkeys and in normal lipoproteinemic humans. In contrast to the production rates calculated from the decay of plasma 3 He-radioactivity, the production rates calculated from lipoproteins labeled with cholesteryl [ 14 C]oleate were approximately 2-3 times greater. In addition to these studies, a plasma cholesteryl ester transacylation activity was demonstrated in vitro when HDL containing doubly labeled cholesteryl esters were incubated with fresh plasma. These results demonstrated that high density lipoprotein cholesteryl esters undergo transacylation in vitro, resulting in release and reesterification of free [ 3 H]cholesterol

  11. New and extended parameterization of the thermodynamic model AIOMFAC: calculation of activity coefficients for organic-inorganic mixtures containing carboxyl, hydroxyl, carbonyl, ether, ester, alkenyl, alkyl, and aromatic functional groups

    Directory of Open Access Journals (Sweden)

    A. Zuend

    2011-09-01

    Full Text Available We present a new and considerably extended parameterization of the thermodynamic activity coefficient model AIOMFAC (Aerosol Inorganic-Organic Mixtures Functional groups Activity Coefficients at room temperature. AIOMFAC combines a Pitzer-like electrolyte solution model with a UNIFAC-based group-contribution approach and explicitly accounts for interactions between organic functional groups and inorganic ions. Such interactions constitute the salt-effect, may cause liquid-liquid phase separation, and affect the gas-particle partitioning of aerosols. The previous AIOMFAC version was parameterized for alkyl and hydroxyl functional groups of alcohols and polyols. With the goal to describe a wide variety of organic compounds found in atmospheric aerosols, we extend here the parameterization of AIOMFAC to include the functional groups carboxyl, hydroxyl, ketone, aldehyde, ether, ester, alkenyl, alkyl, aromatic carbon-alcohol, and aromatic hydrocarbon. Thermodynamic equilibrium data of organic-inorganic systems from the literature are critically assessed and complemented with new measurements to establish a comprehensive database. The database is used to determine simultaneously the AIOMFAC parameters describing interactions of organic functional groups with the ions H+, Li+, Na+, K+, NH4+, Mg2+, Ca2+, Cl, Br, NO3, HSO4, and SO42−. Detailed descriptions of different types of thermodynamic data, such as vapor-liquid, solid-liquid, and liquid-liquid equilibria, and their use for the model parameterization are provided. Issues regarding deficiencies of the database, types and uncertainties of experimental data, and limitations of the model, are discussed. The challenging parameter optimization problem is solved with a novel combination of powerful global minimization

  12. Influence of Dimerization of Lipopeptide Laur-Orn-Orn-Cys-NH2 and an N-terminal Peptide of Human Lactoferricin on Biological Activity.

    Science.gov (United States)

    Kamysz, Elżbieta; Sikorska, Emilia; Dawgul, Małgorzata; Tyszkowski, Rafał; Kamysz, Wojciech

    Lactoferrin (LF) is a naturally occurring antimicrobial peptide that is cleaved by pepsin to lactoferricin (LFcin). LFcin has an enhanced antimicrobial activity as compared to that of LF. Recently several hetero- and homodimeric antimicrobial peptides stabilized by a single disulfide bond linking linear polypeptide chains have been discovered. We have demonstrated that the S-S bond heterodimerization of lipopeptide Laur-Orn-Orn-Cys-NH 2 (peptide III) and the synthetic N -terminal peptide of human lactoferricin (peptide I) yields a dimer (peptide V), which is almost as microbiologically active as the more active monomer and at the same time it is much less toxic. Furthermore, it has been found that the S-S bond homodimerization of both peptide I and peptide III did not affect antimicrobial and haemolytic activity of the compounds. The homo- and heterodimerization of peptides I and III resulted in either reduction or loss of antifungal activity. This work suggests that heterodimerization of antimicrobial lipopeptides via intermolecular disulfide bond might be a powerful modification deserving consideration in the design of antimicrobial peptides.

  13. Structure-activity relationships of the antimicrobial peptide arasin 1 - and mode of action studies of the N-terminal, proline-rich region.

    Directory of Open Access Journals (Sweden)

    Victoria S Paulsen

    Full Text Available Arasin 1 is a 37 amino acid long proline-rich antimicrobial peptide isolated from the spider crab, Hyas araneus. In this work the active region of arasin 1 was identified through structure-activity studies using different peptide fragments derived from the arasin 1 sequence. The pharmacophore was found to be located in the proline/arginine-rich NH(2 terminus of the peptide and the fragment arasin 1(1-23 was almost equally active to the full length peptide. Arasin 1 and its active fragment arasin 1(1-23 were shown to be non-toxic to human red blood cells and arasin 1(1-23 was able to bind chitin, a component of fungal cell walls and the crustacean shell. The mode of action of the fully active N-terminal arasin 1(1-23 was explored through killing kinetic and membrane permeabilization studies. At the minimal inhibitory concentration (MIC, arasin 1(1-23 was not bactericidal and had no membrane disruptive effect. In contrast, at concentrations of 5×MIC and above it was bactericidal and interfered with membrane integrity. We conclude that arasin 1(1-23 has a different mode of action than lytic peptides, like cecropin P1. Thus, we suggest a dual mode of action for arasin 1(1-23 involving membrane disruption at peptide concentrations above MIC, and an alternative mechanism of action, possibly involving intracellular targets, at MIC.

  14. Uncaria rhynchophylla and Rhynchophylline inhibit c-Jun N-terminal kinase phosphorylation and nuclear factor-kappaB activity in kainic acid-treated rats.

    Science.gov (United States)

    Hsieh, Ching-Liang; Ho, Tin-Yun; Su, Shan-Yu; Lo, Wan-Yu; Liu, Chung-Hsiang; Tang, Nou-Ying

    2009-01-01

    Our previous studies have shown that Uncaria rhynchophylla (UR) can reduce epileptic seizures. We hypothesized that UR and its major component rhynchophylline (RH), reduce epileptic seizures in rats treated with kainic acid (KA) by inhibiting nuclear factor-kappaB (NF-kappaB) and activator-protein-1 (AP-1) activity, and by eliminating superoxide anions. Therefore, the level of superoxide anions and the DNA binding activities of NF-kappaB and AP-1 were measured. Sprague-Dawley (SD) rats were pre-treated with UR (1.0 g/kg, i.p.), RH (0.25 mg/kg, i.p.), or valproic acid (VA, 250 mg/kg, i.p.) for 3 days and then KA was administered intra-peritoneal (i.p.). The results indicated that UR, RH, and VA can reduce epileptic seizures and the level of superoxide anions in the blood. Furthermore, KA was demonstrated to induce the DNA binding activities of NF-kappaB and AP-1. However, these inductions were inhibited by pre-treatment with UR, RH, or VA for 3 days. Moreover, UR and RH were shown to be involved in the suppression of c-Jun N-terminal kinase (JNK) phosphorylation. This study suggested that UR and RH have antiepileptic effects in KA-induced seizures and are associated with the regulation of the innate immune system via a reduction in the level of superoxide anions, JNK phosphorylation, and NF-kappaB activation.

  15. Ubiquitin C-terminal electrophiles are activity-based probes for identification and mechanistic study of ubiquitin conjugating machinery.

    Science.gov (United States)

    Love, Kerry Routenberg; Pandya, Renuka K; Spooner, Eric; Ploegh, Hidde L

    2009-04-17

    Protein modification by ubiquitin (Ub) and ubiquitin-like modifiers (Ubl) requires the action of activating (E1), conjugating (E2), and ligating (E3) enzymes and is a key step in the specific destruction of proteins. Deubiquitinating enzymes (DUBs) deconjugate substrates modified with Ub/Ubl's and recycle Ub inside the cell. Genome mining based on sequence homology to proteins with known function has assigned many enzymes to this pathway without confirmation of either conjugating or DUB activity. Function-dependent methodologies are still the most useful for rapid identification or assessment of biological activity of expressed proteins from cells. Activity-based protein profiling uses chemical probes that are active-site-directed for the classification of protein activities in complex mixtures. Here we show that the design and use of an expanded set of Ub-based electrophilic probes allowed us to recover and identify members of each enzyme class in the ubiquitin-proteasome system, including E3 ligases and DUBs with previously unverified activity. We show that epitope-tagged Ub-electrophilic probes can be used as activity-based probes for E3 ligase identification by in vitro labeling and activity studies of purified enzymes identified from complex mixtures in cell lysate. Furthermore, the reactivity of our probe with the HECT domain of the E3 Ub ligase ARF-BP1 suggests that multiple cysteines may be in the vicinity of the E2-binding site and are capable of the transfer of Ub to self or to a substrate protein.

  16. Mechanisms of DNA replication termination.

    Science.gov (United States)

    Dewar, James M; Walter, Johannes C

    2017-08-01

    Genome duplication is carried out by pairs of replication forks that assemble at origins of replication and then move in opposite directions. DNA replication ends when converging replication forks meet. During this process, which is known as replication termination, DNA synthesis is completed, the replication machinery is disassembled and daughter molecules are resolved. In this Review, we outline the steps that are likely to be common to replication termination in most organisms, namely, fork convergence, synthesis completion, replisome disassembly and decatenation. We briefly review the mechanism of termination in the bacterium Escherichia coli and in simian virus 40 (SV40) and also focus on recent advances in eukaryotic replication termination. In particular, we discuss the recently discovered E3 ubiquitin ligases that control replisome disassembly in yeast and higher eukaryotes, and how their activity is regulated to avoid genome instability.

  17. Inhibition of spinal astrocytic c-Jun N-terminal kinase (JNK activation correlates with the analgesic effects of ketamine in neuropathic pain

    Directory of Open Access Journals (Sweden)

    Wang Wen

    2011-01-01

    Full Text Available Abstract Background We have previously reported that inhibition of astrocytic activation contributes to the analgesic effects of intrathecal ketamine on spinal nerve ligation (SNL-induced neuropathic pain. However, the underlying mechanisms are still unclear. c-Jun N-terminal kinase (JNK, a member of mitogen-activated protein kinase (MAPK family, has been reported to be critical for spinal astrocytic activation and neuropathic pain development after SNL. Ketamine can decrease lipopolysaccharide (LPS-induced phosphorylated JNK (pJNK expression and could thus exert its anti-inflammatory effect. We hypothesized that inhibition of astrocytic JNK activation might be involved in the suppressive effect of ketamine on SNL-induced spinal astrocytic activation. Methods Immunofluorescence histochemical staining was used to detect SNL-induced spinal pJNK expression and localization. The effects of ketamine on SNL-induced mechanical allodynia were confirmed by behavioral testing. Immunofluorescence histochemistry and Western blot were used to quantify the SNL-induced spinal pJNK expression after ketamine administration. Results The present study showed that SNL induced ipsilateral pJNK up-regulation in astrocytes but not microglia or neurons within the spinal dorsal horn. Intrathecal ketamine relieved SNL-induced mechanical allodynia without interfering with motor performance. Additionally, intrathecal administration of ketamine attenuated SNL-induced spinal astrocytic JNK activation in a dose-dependent manner, but not JNK protein expression. Conclusions The present results suggest that inhibition of JNK activation may be involved in the suppressive effects of ketamine on SNL-induced spinal astrocyte activation. Therefore, inhibition of spinal JNK activation may be involved in the analgesic effects of ketamine on SNL-induced neuropathic pain.

  18. Inhibition of spinal astrocytic c-Jun N-terminal kinase (JNK) activation correlates with the analgesic effects of ketamine in neuropathic pain

    Science.gov (United States)

    2011-01-01

    Background We have previously reported that inhibition of astrocytic activation contributes to the analgesic effects of intrathecal ketamine on spinal nerve ligation (SNL)-induced neuropathic pain. However, the underlying mechanisms are still unclear. c-Jun N-terminal kinase (JNK), a member of mitogen-activated protein kinase (MAPK) family, has been reported to be critical for spinal astrocytic activation and neuropathic pain development after SNL. Ketamine can decrease lipopolysaccharide (LPS)-induced phosphorylated JNK (pJNK) expression and could thus exert its anti-inflammatory effect. We hypothesized that inhibition of astrocytic JNK activation might be involved in the suppressive effect of ketamine on SNL-induced spinal astrocytic activation. Methods Immunofluorescence histochemical staining was used to detect SNL-induced spinal pJNK expression and localization. The effects of ketamine on SNL-induced mechanical allodynia were confirmed by behavioral testing. Immunofluorescence histochemistry and Western blot were used to quantify the SNL-induced spinal pJNK expression after ketamine administration. Results The present study showed that SNL induced ipsilateral pJNK up-regulation in astrocytes but not microglia or neurons within the spinal dorsal horn. Intrathecal ketamine relieved SNL-induced mechanical allodynia without interfering with motor performance. Additionally, intrathecal administration of ketamine attenuated SNL-induced spinal astrocytic JNK activation in a dose-dependent manner, but not JNK protein expression. Conclusions The present results suggest that inhibition of JNK activation may be involved in the suppressive effects of ketamine on SNL-induced spinal astrocyte activation. Therefore, inhibition of spinal JNK activation may be involved in the analgesic effects of ketamine on SNL-induced neuropathic pain. PMID:21255465

  19. Synthesis and in vitro and in vivo activity of analogs of growth hormone-releasing hormone (GH-RH) with C-terminal agmatine.

    Science.gov (United States)

    Zarandi, M; Csernus, V; Bokser, L; Bajusz, S; Groot, K; Schally, A V

    1990-12-01

    In the search for more active analogs of human growth hormone-releasing hormone (GH-RH), 37 new compounds were synthesized by solid phase methodology, purified, and tested biologically. Most of the analogs contained a sequence of 27 amino acids and N-terminal desaminotyrosine (Dat) and C-terminal agmatine (Agm), which are not amino acids. In addition to Dat in position 1 and Agm in position 29, the majority of the analogs had Ala15 and Nle27 substitutions and one or more additional L- or D-amino acid modifications. [Dat1, Ala15, Nle27]GH-RH(1-28)Agm (MZ-2-51) was the most active analog. Its in vitro GH-releasing potency was 10.5 times higher than that of GH-RH(1-29)NH2 and in the i.v. in vivo assay, MZ-2-51 was 4-5 times more active than the standard. After s.c. administration to rats. MZ-2-51 showed an activity 34 times higher at 15 min and 179 times greater at 30 min than GH-RH(1-29)NH2 and also displayed a prolonged activity. D-Tyr10, D-Lys12, and D-Lys21 homologs of MZ-2-51 also showed enhanced activities. Thus, [Dat1, D-Tyr10, Ala15, Nle27]GH-RH(1-28)Agm (MZ-2-159), [Dat1, D-Lys12, Ala15, Nle27]GH-RH(1-28)AGM (MZ-2-57), and [Dat1, Ala15, D-Lys21, Nle27]GH-RH(1-28)Agm (MZ-2-75) were 4-6 times more active in vitro than GH-RH(1-29)NH2. In vivo, after i.v. administration, analog MZ-2-75 was equipotent and analogs MZ-2-159 and MZ-2-57 about twice as potent as the standard.(ABSTRACT TRUNCATED AT 250 WORDS)

  20. Mutations that abrogate transactivational activity of the feline leukemia virus long terminal repeat do not affect virus replication

    International Nuclear Information System (INIS)

    Abujamra, Ana L.; Faller, Douglas V.; Ghosh, Sajal K.

    2003-01-01

    The U3 region of the LTR of oncogenic Moloney murine leukemia virus (Mo-MuLV) and feline leukemia viruses (FeLV) have been previously reported to activate expression of specific cellular genes in trans, such as MHC class I, collagenase IV, and MCP-1, in an integration-independent manner. It has been suggested that transactivation of these specific cellular genes by leukemia virus U3-LTR may contribute to the multistage process of leukemogenesis. The U3-LTR region, necessary for gene transactivational activity, also contains multiple transcription factor-binding sites that are essential for normal virus replication. To dissect the promoter activity and the gene transactivational activity of the U3-LTR, we conducted mutational analysis of the U3-LTR region of FeLV-A molecular clone 61E. We identified minimal nucleotide substitution mutants on the U3 LTR that did not disturb transcription factor-binding sites but abrogated its ability to transactivate the collagenase gene promoter. To determine if these mutations actually have altered any uncharacterized important transcription factor-binding site, we introduced these U3-LTR mutations into the full-length infectious molecular clone 61E. We demonstrate that the mutant virus was replication competent but could not transactivate cellular gene expression. These results thus suggest that the gene transactivational activity is a distinct property of the LTR and possibly not related to its promoter activity. The cellular gene transactivational activity-deficient mutant FeLV generated in this study may also serve as a valuable reagent for testing the biological significance of LTR-mediated cellular gene activation in the tumorigenesis caused by leukemia viruses

  1. DFT Mechanistic Study of the Selective Terminal C-H Activation of n-Pentane with a Tungsten Allyl Nitrosyl Complex

    KAUST Repository

    Lee, Richmond

    2017-01-17

    Mechanistic insights into the selective C-H terminal activation of n-pentane with tungsten allyl nitrosyl complex reported by Legzdins were gained by employing density functional theory with B3LYP hybrid functional. Using Bader’s atom in molecules (AIM) analysis on the elementary steps of the hydrogen transfer process, TS1 and TS2, it was observed that the calculated H-transfer models were closely similar to Hall’s metal-assisted σ-bond metathesis through bond critical point (BCP) comparisons. One distinguishable feature was the fact that the formal oxidation state of the W changed in the concerted H-transfer process. To better differentiate, we term these processes as ‘Formal Reductive Hydrogen Transfer’ (FRHT) for TS1 and ‘Formal Oxidative Hydrogen Transfer’ (FOHT) for TS2.

  2. DFT Mechanistic Study of the Selective Terminal C-H Activation of n-Pentane with a Tungsten Allyl Nitrosyl Complex

    KAUST Repository

    Lee, Richmond; Tan, Davin; Liu, Chaoli; Li, Huaifeng; Guo, Hao; Shyue, Jing-Jong; Huang, Kuo-Wei

    2017-01-01

    Mechanistic insights into the selective C-H terminal activation of n-pentane with tungsten allyl nitrosyl complex reported by Legzdins were gained by employing density functional theory with B3LYP hybrid functional. Using Bader’s atom in molecules (AIM) analysis on the elementary steps of the hydrogen transfer process, TS1 and TS2, it was observed that the calculated H-transfer models were closely similar to Hall’s metal-assisted σ-bond metathesis through bond critical point (BCP) comparisons. One distinguishable feature was the fact that the formal oxidation state of the W changed in the concerted H-transfer process. To better differentiate, we term these processes as ‘Formal Reductive Hydrogen Transfer’ (FRHT) for TS1 and ‘Formal Oxidative Hydrogen Transfer’ (FOHT) for TS2.

  3. Layer by layer assembly of catalase and amine-terminated ionic liquid onto titanium nitride nanoparticles modified glassy carbon electrode: Study of direct voltammetry and bioelectrocatalytic activity

    International Nuclear Information System (INIS)

    Saadati, Shagayegh; Salimi, Abdollah; Hallaj, Rahman; Rostami, Amin

    2012-01-01

    Highlights: ► Catalase and amine-terminated ionic liquid were immobilized to GC/TiNnp with LBL assembly method. ► First a thin layer of NH 2 -IL is covalently attached to GC/TiNnp electrode using electro-oxidation. ► With alternative assemble of IL and catalase with positive and negative charged, multilayer was formed. ► Immobilized catalase shows excellent electrocatalytic activity toward H 2 O 2 reduction. ► Biosensor response is directly correlated to the number of bilayers. - Abstract: A novel, simple and facile layer by layer (LBL) approach is used for modification of glassy carbon (GC) electrode with multilayer of catalase and nanocomposite containing 1-(3-Aminopropyl)-3-methylimidazolium bromide (amine terminated ionic liquid (NH 2 -IL)) and titanium nitride nanoparticles (TiNnp). First a thin layer of NH 2 -IL is covalently attached to GC/TiNnp electrode using electro-oxidation method. Then, with alternative self assemble positively charged NH 2 -IL and negatively charged catalase a sensitive H 2 O 2 biosensor is constructed, whose response is directly correlated to the number of bilayers. The surface coverage of active catalase per bilayer, heterogeneous electron transfer rate constant (k s ) and Michaelis–Menten constant (K M ) of immobilized catalase were 3.32 × 10 −12 mol cm −2 , 5.28 s −1 and 1.1 mM, respectively. The biosensor shows good stability, high reproducibility, long life-time, and fast amperometric response with the high sensitivity of 380 μA mM −1 cm −2 and low detection limit of 100 nM at concentration range up to 2.1 mM.

  4. Layer by layer assembly of catalase and amine-terminated ionic liquid onto titanium nitride nanoparticles modified glassy carbon electrode: Study of direct voltammetry and bioelectrocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Saadati, Shagayegh [Department of Chemistry, University of Kurdistan, P.O. Box 416, Sanandaj (Iran, Islamic Republic of); Salimi, Abdollah, E-mail: absalimi@uok.ac.ir [Department of Chemistry, University of Kurdistan, P.O. Box 416, Sanandaj (Iran, Islamic Republic of); Research Center for Nanotechnology, University of Kurdistan, P.O. Box 416, Sanandaj (Iran, Islamic Republic of); Hallaj, Rahman; Rostami, Amin [Department of Chemistry, University of Kurdistan, P.O. Box 416, Sanandaj (Iran, Islamic Republic of)

    2012-11-13

    Highlights: Black-Right-Pointing-Pointer Catalase and amine-terminated ionic liquid were immobilized to GC/TiNnp with LBL assembly method. Black-Right-Pointing-Pointer First a thin layer of NH{sub 2}-IL is covalently attached to GC/TiNnp electrode using electro-oxidation. Black-Right-Pointing-Pointer With alternative assemble of IL and catalase with positive and negative charged, multilayer was formed. Black-Right-Pointing-Pointer Immobilized catalase shows excellent electrocatalytic activity toward H{sub 2}O{sub 2} reduction. Black-Right-Pointing-Pointer Biosensor response is directly correlated to the number of bilayers. - Abstract: A novel, simple and facile layer by layer (LBL) approach is used for modification of glassy carbon (GC) electrode with multilayer of catalase and nanocomposite containing 1-(3-Aminopropyl)-3-methylimidazolium bromide (amine terminated ionic liquid (NH{sub 2}-IL)) and titanium nitride nanoparticles (TiNnp). First a thin layer of NH{sub 2}-IL is covalently attached to GC/TiNnp electrode using electro-oxidation method. Then, with alternative self assemble positively charged NH{sub 2}-IL and negatively charged catalase a sensitive H{sub 2}O{sub 2} biosensor is constructed, whose response is directly correlated to the number of bilayers. The surface coverage of active catalase per bilayer, heterogeneous electron transfer rate constant (k{sub s}) and Michaelis-Menten constant (K{sub M}) of immobilized catalase were 3.32 Multiplication-Sign 10{sup -12} mol cm{sup -2}, 5.28 s{sup -1} and 1.1 mM, respectively. The biosensor shows good stability, high reproducibility, long life-time, and fast amperometric response with the high sensitivity of 380 {mu}A mM{sup -1} cm{sup -2} and low detection limit of 100 nM at concentration range up to 2.1 mM.

  5. Chimeric RXFP1 and RXFP2 receptors highlight the similar mechanism of activation utilizing their N-terminal low density lipoprotein class A modules

    Directory of Open Access Journals (Sweden)

    Shoni eBruell

    2013-11-01

    Full Text Available Relaxin family peptide (RXFP receptors 1 and 2 are unique G-protein coupled receptors in that they contain an N-terminal low density lipoprotein type A (LDLa module which is necessary for receptor activation. The current hypothesis suggests that upon ligand binding the LDLa module interacts with the transmembrane (TM domain of a homodimer partner receptor to induce the active receptor conformations. We recently demonstrated that three residues in the N-terminus of the RXFP1 LDLa module are potentially involved in hydrophobic interactions with the receptor to drive activation. RXFP2 shares two out of three of the residues implicated, suggesting that the two LDLa modules could be interchanged without adversely affecting activity. However, in 2007 it was shown that a chimera consisting of the RXFP1 receptor with its LDLa swapped for that of RXFP2 did not signal. We noticed this construct also contained the RXFP2 region linking the LDLa to the leucine-rich repeats. We therefore constructed chimeric RXFP1 and RXFP2 receptors with their LDLa modules swapped immediately C-terminally to the final cysteine residue of the module, retaining the native linker. In addition, we exchanged the TM domains of the chimeras to explore if matching the LDLa module with the TM domain of its native receptor altered activity. All of the chimeras were expressed at the surface of HEK293T cells with ligand binding profiles similar to the wild-type receptors. Importantly, as predicted, ligand binding was able to induce cAMP based signalling. Chimeras of RXFP1 with the LDLa of RXFP2 demonstrated reduced H2 relaxin potency with the pairing of the RXFP2 TM with the RXFP2 LDLa necessary for full ligand efficacy. In contrast the ligand mediated potencies and efficacies on the RXFP2 chimeras were similar suggesting the RXFP1 LDLa module has similar efficacy on the RXFP2 TM domain. Our studies demonstrate the LDLa modules of RXFP1 and RXFP2 modulate receptor activation via a

  6. The biological activity of the human epidermal growth factor receptor is positively regulated by its C-terminal tyrosines

    DEFF Research Database (Denmark)

    Helin, K; Velu, T; Martin, P

    1991-01-01

    mutants in the full length receptor. EGF-dependent transforming ability of the single point mutants is similar to that of the wild type, while that of double mutants is decreased and an even lower activity is present in the triple mutant. In each bioassay, including EGF-dependent focal transformation...... biologically. The EGF-R kinase activity is affected by tyrosine substitution since in vitro phosphorylation of exogenous substrates is reduced in the double and triple mutants. Autophosphorylation, in vivo and in vitro, is also reduced, but not totally abolished in the triple point mutant and Dc123 indicating......The epidermal growth factor receptor (EGF-R) C-terminus contains three conserved tyrosines (Y-1068, Y-1148, Y-1173) which are phosphorylated upon EGF activation. To clarify the functional role of these tyrosines, each has been mutated to phenylalanine and studied as single, double and triple...

  7. Lupeol and its esters: NMR, powder XRD data and in vitro evaluation of cancer cell growth

    Directory of Open Access Journals (Sweden)

    Aline Teixeira Maciel e Silva

    2018-02-01

    Full Text Available ABSTRACT The triterpene lupeol (1 and some of its esters are secondary metabolites produced by species of Celastraceae family, which have being associated with cytotoxic activity. We report herein the isolation of 1, the semi-synthesis of eight lupeol esters and the evaluation of their in vitro activity against nine strains of cancer cells. The reaction of carboxylic acids with 1 and DIC/DMAP was used to obtain lupeol stearate (2, lupeol palmitate (3 lupeol miristate (4, and the new esters lupeol laurate (5, lupeol caprate (6, lupeol caprilate (7, lupeol caproate (8 and lupeol 3’,4’-dimethoxybenzoate (9, with high yields. Compounds 1-9 were identified using FT-IR, 1H, 13C-NMR, CHN analysis and XRD data and were tested in vitro for proliferation of human cancer cell activity. In these assays, lupeol was inactive (GI50> 250µg/mL while lupeol esters 2 -4 and 7 - 9 showed a cytostatic effect. The XRD method was a suitable tool to determine the structure of lupeol and its esters in solid state. Compound 3 showed a selective growth inhibition effect on erythromyeloblastoid leukemia (K-562 cells in a concentration-dependent way. Lupeol esters 4 and 9 showed a selective cytostatic effect with low GI50 values representing promising prototypes for the development of new anticancer drugs.

  8. The C-terminal N-glycosylation sites of the human α1,3/4-fucosyltransferase III, -V and -VI (hFucTIII, -V and -VI) are necessary for the expression of full enzyme activity

    DEFF Research Database (Denmark)

    Christensen, Lise Lotte; Jensen, Uffe Birk; Bross, Peter Gerd

    2000-01-01

    FucTIII enzyme activity to approximately 40% of the activity of the native enzyme. To further analyze the role of the conserved N-glycosylation sites in hFucTIII, -V, and -VI, we made a series of mutant genomic DNAs in which the asparagine residues in the potential C-terminal N-glycosylation sites were replaced...

  9. Monosodium Urate in the Presence of RANKL Promotes Osteoclast Formation through Activation of c-Jun N-Terminal Kinase

    Directory of Open Access Journals (Sweden)

    Jung-Yoon Choe

    2015-01-01

    Full Text Available The aim of this study was to clarify the role of monosodium urate (MSU crystals in receptor activator of nuclear factor kB ligand- (RANKL- RANK-induced osteoclast formation. RAW 264.7 murine macrophage cells were incubated with MSU crystals or RANKL and differentiated into osteoclast-like cells as confirmed by staining for tartrate-resistant acid phosphatase (TRAP and actin ring, pit formation assay, and TRAP activity assay. MSU crystals in the presence of RANKL augmented osteoclast differentiation, with enhanced mRNA expression of NFATc1, cathepsin K, carbonic anhydrase II, and matrix metalloproteinase-9 (MMP-9, in comparison to RAW 264.7 macrophages incubated in the presence of RANKL alone. Treatment with both MSU crystals and RANKL induced osteoclast differentiation by activating downstream molecules in the RANKL-RANK pathway including tumor necrosis factor receptor-associated factor 6 (TRAF-6, JNK, c-Jun, and NFATc1. IL-1b produced in response to treatment with both MSU and RANKL is involved in osteoclast differentiation in part through the induction of TRAF-6 downstream of the IL-1b pathway. This study revealed that MSU crystals contribute to enhanced osteoclast formation through activation of RANKL-mediated pathways and recruitment of IL-1b. These findings suggest that MSU crystals might be a pathologic causative agent of bone destruction in gout.

  10. Termination of Vernakalant-Resistant Atrial Fibrillation by Inhibition of Small-Conductance Ca2+-Activated K+ Channels in Pigs

    DEFF Research Database (Denmark)

    Diness, Jonas Goldin; Skibsbye, Lasse; Simó-Vicens, Rafel

    2017-01-01

    Background Evidence has emerged that small-conductance Ca2+-activated K+ (SK) channels constitute a new target for treatment of atrial fibrillation (AF). SK channels are predominantly expressed in the atria as compared with the ventricles. Various marketed antiarrhythmic drugs are limited by vent...

  11. Actividad de la proteína transportadora de ésteres de colesterol. Polimorfismos del gen en pacientes colombianos con enfermedad coronaria Activity of cholesteryl ester transfer protein. Gene polymorphism in colombian patients with coronary artery disease

    Directory of Open Access Journals (Sweden)

    Alejandra M Giraldo

    2012-08-01

    Full Text Available Introducción: la literatura relaciona la actividad de la proteína transportadora de ésteres de colesterol (CETP con enfermedad coronaria, por reducir el colesterol en las lipoproteínas de alta densidad. Adicionalmente, estudios recientes han identificado variaciones en el gen de la CETP, aunque el papel funcional de algunas de estas variantes sobre la actividad enzimática y la enfermedad coronaria, es desconocido. Objetivos: examinar la asociación de los polimorfismos TaqIB, MspI y RsaI del gen de la CETP y la actividad de la enzima con enfermedad coronaria. Métodos: se evaluó la asociación entre la actividad de la enzima y los polimorfismos TaqIB, MspI y RsaI, en pacientes con obstrucción coronaria documentada por angiografía. Resultados: la angiografía permitió clasificar a los pacientes en dos grupos: uno (213 individuos con obstrucción coronaria no significativa (OC 50%. La edad fue significantemente mayor en el último grupo en comparación con el primero. La actividad de la CETP fue 95,8 y 94,7 pmol/μL.h, para los grupos OC 50%, respectivamente. Solo se encontró diferencia significativa entre los alelos M1 y M2 en la población general. Conclusión: no se halló asociación entre la actividad de la CETP, los polimorfismos TaqBI, MspI, Rsal y la obstrucción coronaria. En este trabajo se describen por primera vez los niveles de CETP en los polimorfismos TaqIB, MspI, Rsal para un grupo de pacientes colombianos. Se debe refinar la descripción del evento coronario, el contexto metabólico de los pacientes y el estudio de haplotipos para encontrar relaciones con enfermedad coronaria.Introduction: literature links the activity of cholesteryl ester transfer protein (CETP with coronary heart disease by lowering cholesterol in high density lipoproteins. Additionally, recent studies have identified variations in the CETP gene, although the functional role of some of these variants on enzyme activity and coronary heart disease is

  12. Phenyl Saligenin Phosphate Induced Caspase-3 and c-Jun N-Terminal Kinase Activation in Cardiomyocyte-Like Cells.

    Science.gov (United States)

    Felemban, Shatha G; Garner, A Christopher; Smida, Fathi A; Boocock, David J; Hargreaves, Alan J; Dickenson, John M

    2015-11-16

    At present, little is known about the effect(s) of organophosphorous compounds (OPs) on cardiomyocytes. In this study, we have investigated the effects of phenyl saligenin phosphate (PSP), two organophosphorothioate insecticides (diazinon and chlorpyrifos), and their acutely toxic metabolites (diazoxon and chlorpyrifos oxon) on mitotic and differentiated H9c2 cardiomyoblasts. OP-induced cytotoxicity was assessed by monitoring MTT reduction, LDH release, and caspase-3 activity. Cytotoxicity was not observed with diazinon, diazoxon, or chlorpyrifos oxon (48 h exposure; 200 μM). Chlorpyrifos-induced cytotoxicity was only evident at concentrations >100 μM. In marked contrast, PSP displayed pronounced cytotoxicity toward mitotic and differentiated H9c2 cells. PSP triggered the activation of JNK1/2 but not ERK1/2, p38 MAPK, or PKB, suggesting a role for this pro-apoptotic protein kinase in PSP-induced cell death. The JNK1/2 inhibitor SP 600125 attenuated PSP-induced caspase-3 and JNK1/2 activation, confirming the role of JNK1/2 in PSP-induced cytotoxicity. Fluorescently labeled PSP (dansylated PSP) was used to identify novel PSP binding proteins. Dansylated PSP displayed cytotoxicity toward differentiated H9c2 cells. 2D-gel electrophoresis profiles of cells treated with dansylated PSP (25 μM) were used to identify proteins fluorescently labeled with dansylated PSP. Proteomic analysis identified tropomyosin, heat shock protein β-1, and nucleolar protein 58 as novel protein targets for PSP. In summary, PSP triggers cytotoxicity in differentiated H9c2 cardiomyoblasts via JNK1/2-mediated activation of caspase-3. Further studies are required to investigate whether the identified novel protein targets of PSP play a role in the cytotoxicity of this OP, which is usually associated with the development of OP-induced delayed neuropathy.

  13. 21 CFR 172.854 - Polyglycerol esters of fatty acids.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Polyglycerol esters of fatty acids. 172.854 Section... HUMAN CONSUMPTION Multipurpose Additives § 172.854 Polyglycerol esters of fatty acids. Polyglycerol esters of fatty acids, up to and including the decaglycerol esters, may be safely used in food in...

  14. Cobalt-catalyzed hydrogenation of esters to alcohols: unexpected reactivity trend indicates ester enolate intermediacy.

    Science.gov (United States)

    Srimani, Dipankar; Mukherjee, Arup; Goldberg, Alexander F G; Leitus, Gregory; Diskin-Posner, Yael; Shimon, Linda J W; Ben David, Yehoshoa; Milstein, David

    2015-10-12

    The atom-efficient and environmentally benign catalytic hydrogenation of carboxylic acid esters to alcohols has been accomplished in recent years mainly with precious-metal-based catalysts, with few exceptions. Presented here is the first cobalt-catalyzed hydrogenation of esters to the corresponding alcohols. Unexpectedly, the evidence indicates the unprecedented involvement of ester enolate intermediates. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Fatty acid methyl esters production: chemical process variables

    Directory of Open Access Journals (Sweden)

    Paulo César Narváez Rincón

    2004-05-01

    Full Text Available The advantages of fatty acid methyl esters as basic oleochemicals over fatty acids, the seventies world energy crisis and the use of those oleochemicals as fuels, have increased research interest on fats and oils trans-esterification. In this document, a review about basic aspects, uses, process variables and problems associated to the production process of fatty acid methyl esters is presented. A global view of recent researches, most of them focused in finding a new catalyst with same activity as the alcohol-soluble hydroxides (NaOH, KOH, and suitable to be used in transforming fats and oils with high levels of free fatty acids and water avoiding separation problems and reducing process costs, is also discussed.

  16. Sulfur deactivation of fatty ester hydrogenolysis catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Brands, D.S.; U-A-Sai, G.; Poels, E.K.; Bliek, A. [Univ. of Amsterdam (Netherlands). Dept. of Chemical Engineering

    1999-08-15

    Trace organosulfur compounds present as natural impurities in oleochemical feedstocks may lead to activation of copper-containing catalysts applied for hydrogenolysis of esters toward fatty alcohols. In this paper, the sulfur deactivation of Cu/SiO{sub 2} and Cu/ZnO/SiO{sub 2} catalysts was studied in the liquid-phase hydrogenolysis of methyl palmitate. The rate of deactivation is fast and increases as a function of the sulfur-containing compound present: octadecanethiol {approx} dihexadecyl disulfide < benzyl isothiocyanate < methyl p-toluene sulfonate < dihexadecyl sulfide < dibenzothiophene. The rapid deactivation is caused by the fact that sulfur is quantitatively removed from the reaction mixture and because mainly surface sulfides are formed under hydrogenolysis conditions. The life time of a zinc-promoted catalyst is up to two times higher than that of the Cu/SiO{sub 2} catalyst, most likely due to zinc surface sulfide formation. The maximum sulfur coverage obtained after full catalyst deactivation with dibenzothiophene and dihexadecyl sulfide--the sulfur compounds that cause the fastest deactivation--may be as low as 0.07. This is due to the fact that decomposition of these compounds as well as the hydrogenolysis reaction itself proceeds on ensembles of copper atoms. Catalyst regeneration studies reveal that activity cannot be regained by reduction or combined oxidation/reduction treatments. XRD, TPR, and TPO results confirm that no distinct bulk copper or zinc sulfide or sulfate phases are present.

  17. Gamma-aminobutyric acid esters. 1. Synthesis, brain uptake, and pharmacological studies of aliphatic and steroid esters of gamma-aminobutyric acid

    International Nuclear Information System (INIS)

    Shashoua, V.E.; Jacob, J.N.; Ridge, R.; Campbell, A.; Baldessarini, R.J.

    1984-01-01

    Labeled and unlabeled aliphatic and steroid esters of gamma-amino[U- 14 C]butyric acid (GABA) were synthesized and tested for their capacity to penetrate the blood-brain barrier and for evidence of central neuropharmacological activity in rodents. The uptake of the labeled 9,12,15-octadecatrienyl (linolenyl), 3-cholesteryl, 1-butyl, and the 9-fluoro-11 beta,17-dihydroxy-16 alpha-methyl-3,20-dioxopregna -1,4-dien-21-yl (dexamethasone) esters of GABA into mouse brain increased 2-, 25-, 74-, and 81-fold over GABA, respectively. The cholesteryl ester of GABA depressed the general motor activity of mice and rats in a dose-dependent manner, whereas the 1-butyl, linolenyl, and dexamethasone esters were inactive by this test. Studies of the rates of hydrolysis, GABA receptor binding capacity, and octanol/water partition coefficients indicated that pharmacological activity of the esters after entry into the central nervous system (CNS) was dependent on their capacity to release GABA by enzymatic hydrolysis and their lipid solubility

  18. The C-terminal region of the non-structural protein 2B from Hepatitis A Virus demonstrates lipid-specific viroporin-like activity

    Science.gov (United States)

    Shukla, Ashutosh; Dey, Debajit; Banerjee, Kamalika; Nain, Anshu; Banerjee, Manidipa

    2015-10-01

    Viroporins are virally encoded, membrane-active proteins, which enhance viral replication and assist in egress of viruses from host cells. The 2B proteins in the picornaviridae family are known to have viroporin-like properties, and play critical roles during virus replication. The 2B protein of Hepatitis A Virus (2B), an unusual picornavirus, is somewhat dissimilar from its analogues in several respects. HAV 2B is approximately 2.5 times the length of other 2B proteins, and does not disrupt calcium homeostasis or glycoprotein trafficking. Additionally, its membrane penetrating properties are not yet clearly established. Here we show that the membrane interacting activity of HAV 2B is localized in its C-terminal region, which contains an alpha-helical hairpin motif. We show that this region is capable of forming small pores in membranes and demonstrates lipid specific activity, which partially rationalizes the intracellular localization of full-length 2B. Using a combination of biochemical assays and molecular dynamics simulation studies, we also show that HAV 2B demonstrates a marked propensity to dimerize in a crowded environment, and probably interacts with membranes in a multimeric form, a hallmark of other picornavirus viroporins. In sum, our study clearly establishes HAV 2B as a bona fide viroporin in the picornaviridae family.

  19. Lipase catalyzed ester synthesis for food processing industries

    Directory of Open Access Journals (Sweden)

    Aravindan Rajendran

    2009-02-01

    Full Text Available Lipases are one of the most important industrial biocatalyst which catalyzes the hydrolysis of lipids. It can also reverse the reaction at minimum water activity. Because of this pliable nature, it is widely exploited to catalyze the diverse bioconversion reactions, such as hydrolysis, esterification, interesterification, alcoholysis, acidolysis and aminolysis. The property to synthesize the esters from the fatty acids and glycerol promotes its use in various ester synthesis. The esters synthesized by lipase finds applications in numerous fields such as biodiesel production, resolution of the recemic drugs, fat and lipid modification, flavour synthesis, synthesis of enantiopure pharmaceuticals and nutraceuticals. It plays a crucial role in the food processing industries since the process is unaffected by the unwanted side products. Lipase modifications such as the surfactant coating, molecular imprinting to suit for the non-aqueous ester synthesis have also been reported. This review deals with lipase catalyzed ester synthesis, esterification strategies, optimum conditions and their applications in food processing industries.Lipases são catalizadores industriais dos mais importantes, os quais catalizam a hidrólise de lipídeos. Também podem reverter a reação a um mínimo de atividade de água. Devido sua natureza flexível, é amplamente explorada para catalizar uma diversidade de reações de bioconversão como hidrólise, esterificação, interesterificação, alcoólise, acidólise e aminólise. A propriedade de síntese de esteres a partir de ácidos graxos e glicerol promoveu seu uso em várias sínteses de esteres. Os esteres sintetizados por lipases encontram aplicação em numerosos campos como a produção de biodiesel, resolução de drogas racêmicas, modificação de gorduras e lipídios, sintese de aromas, síntese de produtos farmacêuticos enantiopuro e nutracêuticos. As lipases possuem um papel crucial nas indústrias de

  20. C-terminal β9-strand of the cyclic nucleotide-binding homology domain stabilizes activated states of Kv11.1 channels.

    Directory of Open Access Journals (Sweden)

    Chai Ann Ng

    Full Text Available Kv11.1 potassium channels are important for regulation of the normal rhythm of the heartbeat. Reduced activity of Kv11.1 channels causes long QT syndrome type 2, a disorder that increases the risk of cardiac arrhythmias and sudden cardiac arrest. Kv11.1 channels are members of the KCNH subfamily of voltage-gated K(+ channels. However, they also share many similarities with the cyclic nucleotide gated ion channel family, including having a cyclic nucleotide-binding homology (cNBH domain. Kv11.1 channels, however, are not directly regulated by cyclic nucleotides. Recently, crystal structures of the cNBH domain from mEAG and zELK channels, both members of the KCNH family of voltage-gated potassium channels, revealed that a C-terminal β9-strand in the cNBH domain occupied the putative cyclic nucleotide-binding site thereby precluding binding of cyclic nucleotides. Here we show that mutations to residues in the β9-strand affect the stability of the open state relative to the closed state of Kv11.1 channels. We also show that disrupting the structure of the β9-strand reduces the stability of the inactivated state relative to the open state. Clinical mutations located in this β9-strand result in reduced trafficking efficiency, which suggests that binding of the C-terminal β9-strand to the putative cyclic nucleotide-binding pocket is also important for assembly and trafficking of Kv11.1 channels.

  1. Regulator of differentiation 1 (ROD1) binds to the amphipathic C-terminal peptide of thrombospondin-4 and is involved in its mitogenic activity.

    Science.gov (United States)

    Sadvakassova, Gulzhakhan; Dobocan, Monica C; Difalco, Marcos R; Congote, Luis F

    2009-09-01

    The matrix protein thrombospondin-4 has an acidic amphipathic C-terminal peptide (C21) which stimulates erythroid cell proliferation. Here we show that C21 stimulates red cell formation in anemic mice in vivo. In vitro experiments indicated that the peptide-mediated increase of erythroid colony formation in cultures of human CD34+ hematopoietic progenitor cells was possible only under continuous presence of erythropoietin. In the absence of this cytokine, C21 stimulated exclusively myeloid colony formation. Therefore, the peptide is not a specific erythroid differentiation factor. In fact, it is mitogenic in non-erythroid cells, such as skin fibroblasts and kidney epithelial cells. In erythroleukemic TF-1 cells, it actually decreased the production of the erythroid differentiation marker glycophorin A. C21-affinity chromatography revealed regulator of differentiation 1 (ROD1) as a major C21-binding protein. ROD1 is the hematopoietic cell paralog of polypyrimidine tract binding proteins (PTBs), RNA splice regulators which regulate differentiation by repressing tissue-specific exons. ROD1 binding to C21 was strongly inhibited by synthetic RNAs in the order poly A > poly U > poly G = poly C and was weakly inhibited by a synthetic phosphorylated peptide mimicking the C-terminal domain of RNA polymerase II. Cellular overexpression or knockdown experiments of ROD1 suggest a role for this protein in the mitogenic activity of C21. Since the nuclear proteins ROD1 and PTBs regulate differentiation at a posttranscriptional level and there is a fast nuclear uptake of C21, we put forward the idea that the peptide is internalized, goes to the nucleus and maintains cells in a proliferative state by supporting ROD1-mediated inhibition of differentiation.

  2. Simplified Fiber-Wireless Distribution of HD Video in Passive and Active W-band Close Proximity Terminals

    DEFF Research Database (Denmark)

    Lebedev, Alexander; Rodes Lopez, Roberto; Yu, Xianbin

    2012-01-01

    We experimentally demonstrate uncompressed high-definition (HD) video distribution at 84 GHz Radio over Fiber link achieving up to 3 meters of wireless transmission. We experimentally emulate Metro-Access architecture by deploying single/multimode fibers. Passive and active approaches for remote...... antenna unit (RAU) are experimentally investigated. The bit error rate (BER) performance of the optical and wireless channels is reported. A successful transmission of uncompressed HD video in the W-band wireless channel is demonstrated with prospects to pave the way for application-focused fiber-wireless...

  3. Enhancement of the Enterocin CRL35 Activity by a Synthetic Peptide Derived from the NH2-Terminal Sequence

    Science.gov (United States)

    Saavedra, Lucila; Minahk, Carlos; de Ruiz Holgado, Aída P.; Sesma, Fernando

    2004-01-01

    The enterocin CRL35 biosynthetic gene cluster was cloned and sequenced. The sequence was revealed to be highly identical to that of the mundticin KS gene cluster (S. Kawamoto, J. Shima, R. Sato, T. Eguchi, S. Ohmomo, J. Shibato, N. Horikoshi, K. Takeshita, and T. Sameshima, Appl. Environ. Microbiol. 68:3830-3840, 2002). Short synthetic peptides were designed based on the bacteriocin sequence and were evaluated in antimicrobial competitive assays. The peptide KYYGNGVSCNKKGCS produced an enhancement of enterocin CRL35 antimicrobial activity in a buffer system. PMID:15215149

  4. Intrinsic terminators in Mycoplasma hyopneumoniae transcription.

    Science.gov (United States)

    Fritsch, Tiago Ebert; Siqueira, Franciele Maboni; Schrank, Irene Silveira

    2015-04-08

    Mycoplasma hyopneumoniae, an important pathogen of swine, exhibits a low guanine and cytosine (GC) content genome. M. hyopneumoniae genome is organised in long transcriptional units and promoter sequences have been mapped upstream of all transcription units. These analysis provided insights into the gene organisation and transcription initiation at the genome scale. However, the presence of transcriptional terminator sequences in the M. hyopneumoniae genome is poorly understood. In silico analyses demonstrated the presence of putative terminators in 82% of the 33 monocistronic units (mCs) and in 74% of the 116 polycistronic units (pCs) considering different classes of terminators. The functional activity of 23 intrinsic terminators was confirmed by RT-PCR and qPCR. Analysis of all terminators found by three software algorithms, combined with experimental results, allowed us to propose a pattern of RNA hairpin formation during the termination process and to predict the location of terminators in the M. hyopneumoniae genome sequence. The stem-loop structures of intrinsic terminators of mycoplasma diverge from the pattern of terminators found in other bacteria due the low content of guanine and cytosine. In M. hyopneumoniae, transcription can end after a transcriptional unit and before its terminator sequence and can also continue past the terminator sequence with RNA polymerases gradually releasing the RNA.

  5. Synthesis of a new energetic nitrate ester

    Energy Technology Data Exchange (ETDEWEB)

    Chavez, David E [Los Alamos National Laboratory

    2008-01-01

    Nitrate esters have been known as useful energetic materials since the discovery of nitroglycerin by Ascanio Sobrero in 1846. The development of methods to increase the safety and utility of nitroglycerin by Alfred Nobel led to the revolutionary improvement in the utility of nitroglycerin in explosive applications in the form of dynamite. Since then, many nitrate esters have been prepared and incorporated into military applications such as double-based propellants, detonators and as energetic plasticizers. Nitrate esters have also been shown to have vasodilatory effects in humans and thus have been studied and used for treatments of ailments such as angina. The mechanism of the biological response towards nitrate esters has been elucidated recently. Interestingly, many of the nitrate esters used for military purposes are liquids (ethylene glycol dinitrate, propylene glycol dinitrate, etc). Pentaerythritol tetranitrate (PETN) is one of the only solid nitrate esters, besides nitrocellulose, that is used in any application. Unfortunately, PETN melting point is above 100 {sup o}C, and thus must be pressed as a solid for detonator applications. A more practical material would be a melt-castable explosive, for potential simplification of manufacturing processes. Herein we describe the synthesis of a new energetic nitrate ester (1) that is a solid at ambient temperatures, has a melting point of 85-86 {sup o}C and has the highest density of any known nitrate ester composed only of carbon, hydrogen, nitrogen and oxygen. We also describe the chemical, thermal and sensitivity properties of 1 as well as some preliminary explosive performance data.

  6. Disruption of Trichoderma reesei cre2, encoding an ubiquitin C-terminal hydrolase, results in increased cellulase activity

    Science.gov (United States)

    2011-01-01

    Background The filamentous fungus Trichoderma reesei (Hypocrea jecorina) is an important source of cellulases for use in the textile and alternative fuel industries. To fully understand the regulation of cellulase production in T. reesei, the role of a gene known to be involved in carbon regulation in Aspergillus nidulans, but unstudied in T. reesei, was investigated. Results The T. reesei orthologue of the A. nidulans creB gene, designated cre2, was identified and shown to be functional through heterologous complementation of a creB mutation in A. nidulans. A T. reesei strain was constructed using gene disruption techniques that contained a disrupted cre2 gene. This strain, JKTR2-6, exhibited phenotypes similar to the A. nidulans creB mutant strain both in carbon catabolite repressing, and in carbon catabolite derepressing conditions. Importantly, the disruption also led to elevated cellulase levels. Conclusions These results demonstrate that cre2 is involved in cellulase expression. Since the disruption of cre2 increases the amount of cellulase activity, without severe morphological affects, targeting creB orthologues for disruption in other industrially useful filamentous fungi, such as Aspergillus oryzae, Trichoderma harzianum or Aspergillus niger may also lead to elevated hydrolytic enzyme activity in these species. PMID:22070776

  7. Disruption of Trichoderma reesei cre2, encoding an ubiquitin C-terminal hydrolase, results in increased cellulase activity

    Directory of Open Access Journals (Sweden)

    Denton Jai A

    2011-11-01

    Full Text Available Abstract Background The filamentous fungus Trichoderma reesei (Hypocrea jecorina is an important source of cellulases for use in the textile and alternative fuel industries. To fully understand the regulation of cellulase production in T. reesei, the role of a gene known to be involved in carbon regulation in Aspergillus nidulans, but unstudied in T. reesei, was investigated. Results The T. reesei orthologue of the A. nidulans creB gene, designated cre2, was identified and shown to be functional through heterologous complementation of a creB mutation in A. nidulans. A T. reesei strain was constructed using gene disruption techniques that contained a disrupted cre2 gene. This strain, JKTR2-6, exhibited phenotypes similar to the A. nidulans creB mutant strain both in carbon catabolite repressing, and in carbon catabolite derepressing conditions. Importantly, the disruption also led to elevated cellulase levels. Conclusions These results demonstrate that cre2 is involved in cellulase expression. Since the disruption of cre2 increases the amount of cellulase activity, without severe morphological affects, targeting creB orthologues for disruption in other industrially useful filamentous fungi, such as Aspergillus oryzae, Trichoderma harzianum or Aspergillus niger may also lead to elevated hydrolytic enzyme activity in these species.

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    Data.gov (United States)

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    Data.gov (United States)

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    Data.gov (United States)

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    Data.gov (United States)

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    Data.gov (United States)

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    Data.gov (United States)

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    Data.gov (United States)

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    Data.gov (United States)

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    Data.gov (United States)

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    Data.gov (United States)

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    Data.gov (United States)

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  7. Organizational Relationship Termination Competence

    DEFF Research Database (Denmark)

    Ritter, Thomas; Geersbro, Jens

    2011-01-01

    termination are found to significantly affect a firm's relationship termination competence. The findings suggest that managers should regard termination as a legitimate option in customer relationship management. In order to decrease the number of unwanted customers, managers must accept termination......Most firms are involved in a number of customer relationships that drain the firm's resources. However, many firms are hesitant to address this problem. This paper investigates customer relationship termination at the organizational level. We develop and analyze the organizational dimensions...... of organizational termination in order to improve our understanding of the management of termination. The impact of these termination dimensions on the percentage of unwanted customers is developed and tested using PLS on data gathered from a cross-sectional survey of more than 800 sales representatives. We find...

  8. kink Terminal Aerodrome Forecast

    Data.gov (United States)

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    Data.gov (United States)

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