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Sample records for 5-phosphate reductoisomerase mep

  1. Inhibition of green tea and the catechins against 1-deoxy-d-xylulose 5-phosphate reductoisomerase, the key enzyme of the MEP terpenoid biosynthetic pathway.

    Science.gov (United States)

    Hui, Xian; Liu, Hui; Tian, Fang-Lin; Li, Fei-Fei; Li, Heng; Gao, Wen-Yun

    2016-09-01

    1-Deoxy-d-xylulose 5-phosphate reductoisomerase (DXR) is the first committed enzyme in the MEP terpenoid biosynthetic pathway and also a validated antimicrobial target. Green tea which is rich in polyphenolic components such as the catechins, possesses a plenty of pharmacological activities, in particular an antibacterial effect. To uncover the antibacterial mechanism of green tea and to seek new DXR inhibitors from natural sources, the DXR inhibitory activity of green tea and its main antimicrobial catechins were investigated in this study. The results show that the raw extract of green tea and its ethyl acetate fraction are able to suppress DXR activity explicitly. Further determination of the DXR inhibitory capacity of eight catechin compounds demonstrates that the most active compound is gallocatechin gallate that is able to inhibit around 50% activity of DXR at 25μM. Based on these data, the primary structure-activity relationship of the catechins against DXR is discussed. This study would be very helpful to elucidate the antimicrobial mechanism of green tea and the catechins and also would be very useful to direct the rational utilization of them as food additives.

  2. 1-deoxy-D-xylulose-5-phosphate reductoisomerases, and methods of use

    Energy Technology Data Exchange (ETDEWEB)

    Croteau, Rodney B. (Pullman, WA); Lange, Bernd M. (Pullman, WA)

    2002-07-16

    The present invention relates to isolated DNA sequences which code for the expression of plant 1-deoxy-D-xylulose-5-phosphate reductoisomerase protein, such as the sequence presented in SEQ ID NO:1 which encodes a 1-deoxy-D-xylulose-5-phosphate reductoisomerase protein from peppermint (Mentha x piperita). Additionally, the present invention relates to isolated plant 1-deoxy-D-xylulose-5-phosphate reductoisomerase protein. In other aspects, the present invention is directed to replicable recombinant cloning vehicles comprising a nucleic acid sequence which codes for a plant 1-deoxy-D-xylulose-5-phosphate reductoisomerase, to modified host cells transformed, transfected, infected and/or injected with a recombinant cloning vehicle and/or DNA sequence of the invention.

  3. 1-deoxy-d-xylulose-5-phosphate reductoisomerases and method of use

    Energy Technology Data Exchange (ETDEWEB)

    Croteau, Rodney B. (Pullman, WA); Lange, Bernd M. (Pullman, WA)

    2001-01-01

    The present invention relates to isolated DNA sequences which code for the expression of plant 1-deoxy-D-xylulose-5-phosphate reductoisomerase protein, such as the sequence presented in SEQ ID NO:1 which encodes a 1-deoxy-D-xylulose-5-phosphate reductoisomerase protein from peppermint (Mentha x piperita). Additionally, the present invention relates to isolated plant 1-deoxy-D-xylulose-5-phosphate reductoisomerase protein. In other aspects, the present invention is directed to replicable recombinant cloning vehicles comprising a nucleic acid sequence which codes for a plant 1-deoxy-D-xylulose-5-phosphate reductoisomerase, to modified host cells transformed, transfected, infected and/or injected with a recombinant cloning vehicle and/or DNA sequence of the invention.

  4. Deoxyxylulose 5-phosphate reductoisomerase is not a rate-determining enzyme for essential oil production in spike lavender.

    Science.gov (United States)

    Mendoza-Poudereux, Isabel; Muñoz-Bertomeu, Jesús; Arrillaga, Isabel; Segura, Juan

    2014-11-01

    Spike lavender (Lavandula latifolia) is an economically important aromatic plant producing essential oils, whose components (mostly monoterpenes) are mainly synthesized through the plastidial methylerythritol 4-phosphate (MEP) pathway. 1-Deoxy-D-xylulose-5-phosphate (DXP) synthase (DXS), that catalyzes the first step of the MEP pathway, plays a crucial role in monoterpene precursors biosynthesis in spike lavender. To date, however, it is not known whether the DXP reductoisomerase (DXR), that catalyzes the conversion of DXP into MEP, is also a rate-limiting enzyme for the biosynthesis of monoterpenes in spike lavender. To investigate it, we generated transgenic spike lavender plants constitutively expressing the Arabidopsis thaliana DXR gene. Although two out of the seven transgenic T0 plants analyzed accumulated more essential oils than the controls, this is hardly imputable to the DXR transgene effect since a clear correlation between transcript accumulation and monoterpene production could not be established. Furthermore, these increased essential oil phenotypes were not maintained in their respective T1 progenies. Similar results were obtained when total chlorophyll and carotenoid content in both T0 transgenic plants and their progenies were analyzed. Our results then demonstrate that DXR enzyme does not play a crucial role in the synthesis of plastidial monoterpene precursors, suggesting that the control flux of the MEP pathway in spike lavender is primarily exerted by the DXS enzyme.

  5. Enhanced flux through the methylerythritol 4-phosphate pathway in Arabidopsis plants overexpressing deoxyxylulose 5-phosphate reductoisomerase.

    Science.gov (United States)

    Carretero-Paulet, Lorenzo; Cairó, Albert; Botella-Pavía, Patricia; Besumbes, Oscar; Campos, Narciso; Boronat, Albert; Rodríguez-Concepción, Manuel

    2006-11-01

    The methylerythritol 4-phosphate (MEP) pathway synthesizes the precursors for an astonishing diversity of plastid isoprenoids, including the major photosynthetic pigments chlorophylls and carotenoids. Since the identification of the first two enzymes of the pathway, deoxyxylulose 5-phoshate (DXP) synthase (DXS) and DXP reductoisomerase (DXR), they both were proposed as potential control points. Increased DXS activity has been shown to up-regulate the production of plastid isoprenoids in all systems tested, but the relative contribution of DXR to the supply of isoprenoid precursors is less clear. In this work, we have generated transgenic Arabidopsis thaliana plants with altered DXS and DXR enzyme levels, as estimated from their resistance to clomazone and fosmidomycin, respectively. The down-regulation of DXR resulted in variegation, reduced pigmentation and defects in chloroplast development, whereas DXR-overexpressing lines showed an increased accumulation of MEP- derived plastid isoprenoids such as chlorophylls, carotenoids, and taxadiene in transgenic plants engineered to produce this non-native isoprenoid. Changes in DXR levels in transgenic plants did not result in changes in DXS gene expression or enzyme accumulation, confirming that the observed effects on plastid isoprenoid levels in DXR-overexpressing lines were not an indirect consequence of altering DXS levels. The results indicate that the biosynthesis of MEP (the first committed intermediate of the pathway) limits the production of downstream isoprenoids in Arabidopsis chloroplasts, supporting a role for DXR in the control of the metabolic flux through the MEP pathway.

  6. Crystal structure of 1-deoxy-d-xylulose 5-phosphate reductoisomerase from the hyperthermophile Thermotoga maritima for insights into the coordination of conformational changes and an inhibitor binding.

    Science.gov (United States)

    Takenoya, Mihoko; Ohtaki, Akashi; Noguchi, Keiichi; Endo, Kiwamu; Sasaki, Yasuyuki; Ohsawa, Kanju; Yajima, Shunsuke; Yohda, Masafumi

    2010-06-01

    Isopentenyl diphosphate is a precursor of various isoprenoids and is produced by the 2-C-methyl-d-erythritol 4-phosphate (MEP) pathway in plastids of plants, protozoa and many eubacteria. A key enzyme in the MEP pathway, 1-deoxy-d-xylulose 5-phosphate reductoisomerase (DXR), has been shown to be the target of fosmidomycin, which works as an antimalarial, antibacterial and herbicidal compound. In this paper, we report studies of kinetics and the crystal structures of the thermostable DXR from the hyperthermophile Thermotoga maritima. Unlike the mesophilic DXRs, Thermotoga DXR (tDXR) showed activity only with Mg(2+) at its growth temperature. We solved the crystal structures of tDXR with and without fosmidomycin. The structure without fosmidomycin but unexpectedly bound with 2-methyl-2,4-pentanediol (MPD), revealing a new extra space available for potential drug design. This structure adopted the closed form by rigid domain rotation but without the flexible loop over the active site, which was considered as a novel conformation. Further, the conserved Asp residue responsible for cation binding seemed to play an important role in adjusting the position of fosmidomycin. Taken together, our kinetic and the crystal structures illustrate the binding mode of fosmidomycin that leads to its slow, tight binding according to the conformational changes of DXR.

  7. Molecular cloning, characterization and expression analysis of the gene encoding 1-deoxy-D-xylulose 5-phosphate reductoisomerase from Aquilaria sinensis (Lour.) Gilg

    Indian Academy of Sciences (India)

    Juan Liu; Yanhong Xu; Liang Liang; Jianhe Wei

    2015-06-01

    The major constituents of agarwood oils are sesquiterpenes that are obtained from isoprenoid precursors through the plastidial methylerythritol phosphate (MEP) pathway and the cytosolic mevalonate pathway. In this study, a novel full-length cDNA of 1-deoxy-D-xylulose 5-phosphate reductoisomerase (DXR), which was the second key enzyme in the plastid MEP pathway of sesquiterpenes biosynthesis was isolated from the stem of Aquilaria sinensis (Lour.) Gilg by the methods of reverse transcription polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE) technique for the first time, and named as AsDXR. The full-length cDNA of AsDXR was 1768 bp, containing a 1437 bp open reading frame (ORF) encoding a polypeptide of 478 amino acids with a molecular weight of 51.859 kD and the theoretical isoelectric point of 6.29. Comparative and bioinformatic analysis of the deduced AsDXR protein showed extensive homology with DXRs from other plant species, especially Theobroma cacao and Gossypium barbadense, and contained a conserved transit peptide for plastids, and extended pro-rich region and a highly conserved NADPH-binding motif owned by all plant DXRs. Southern blot analysis indicated that AsDXR belonged to a small gene family. Tissue expression pattern analysis revealed that AsDXR expressed strongly in root and stem, but weakly in leaf. Additionally, AsDXR expression was found to be activated by exogenous elicitor of MeJA (methyl jasmonate). The contents of three sesquiterpenes ($\\alpha$-guaiene, $\\alpha$-humulene and $\\delta$-guaiene) were significantly induced by MeJA. This study enables us to further elucidate the role of AsDXR in the biosynthesis of agarwood sesquiterpenes in A. sinensis at the molecular level.

  8. Structure of 1-deoxy-d-xylulose 5-phosphate reductoisomerase in a quaternary complex with a magnesium ion, NADPH and the antimalarial drug fosmidomycin

    Energy Technology Data Exchange (ETDEWEB)

    Yajima, Shunsuke, E-mail: yshun@nodai.ac.jp; Hara, Kodai; Iino, Daisuke; Sasaki, Yasuyuki [Department of Bioscience, Tokyo University of Agriculture, Setagaya-ku, Tokyo 156-8502 (Japan); Kuzuyama, Tomohisa [Biotechnology Research Center, University of Tokyo, Bunkyo-ku, Tokyo 113-8657 (Japan); Ohsawa, Kanju [Department of Bioscience, Tokyo University of Agriculture, Setagaya-ku, Tokyo 156-8502 (Japan); Seto, Haruo [Department of Applied Biology and Chemistry, Tokyo University of Agriculture, Setagaya-ku, Tokyo 156-8502 (Japan); Department of Bioscience, Tokyo University of Agriculture, Setagaya-ku, Tokyo 156-8502 (Japan)

    2007-06-01

    The crystal structure of 1-deoxy-d-xylulose 5-phosphate reductoisomerase (DXR) from Escherichia coli complexed with Mg{sup 2+}, NADPH and fosmidomycin was determined at 2.2 Å resolution. The structure showed a well defined loop conformation at the active site of DXR. The crystal structure of 1-deoxy-d-xylulose 5-phosphate reductoisomerase (DXR) from Escherichia coli complexed with Mg{sup 2+}, NADPH and fosmidomycin was solved at 2.2 Å resolution. DXR is the key enzyme in the 2-C-methyl-d-erythritol 4-phosphate pathway and is an effective target of antimalarial drugs such as fosmidomycin. In the crystal structure, electron density for the flexible loop covering the active site was clearly observed, indicating the well ordered conformation of DXR upon substrate binding. On the other hand, no electron density was observed for the nicotinamide-ribose portion of NADPH and the position of Asp149 anchoring Mg{sup 2+} was shifted by NADPH in the active site.

  9. Cloning, Characterization, and Immunolocalization of a Mycorrhiza-Inducible 1-Deoxy-D-Xylulose 5-Phosphate Reductoisomerase in Arbuscule-Containing Cells of Maize1

    Science.gov (United States)

    Hans, Joachim; Hause, Bettina; Strack, Dieter; Walter, Michael H.

    2004-01-01

    Colonization of plant roots by symbiotic arbuscular mycorrhizal fungi frequently leads to the accumulation of several apocarotenoids. The corresponding carotenoid precursors originate from the plastidial 2-C-methyl-d-erythritol 4-phosphate pathway. We have cloned and characterized 1-deoxy-d-xylulose 5-phosphate reductoisomerase (DXR), catalyzing the first committed step of the pathway, from maize (Zea mays). Functional identification was accomplished by heterologous expression of sequences coding for the mature protein in Escherichia coli. DXR is up-regulated in maize roots during mycorrhization as shown at transcript and protein levels, but is also abundant in leaves and young seedlings. Inspection of sequenced genomes and expressed sequence tag (EST) databases argue for a single-copy DXR gene. Immunolocalization studies in mycorrhizal roots using affinity-purified antibodies revealed a DXR localization in plastids around the main symbiotic structures, the arbuscules. DXR protein accumulation is tightly correlated with arbuscule development. The highest level of DXR protein is reached around maturity and initial senescence of these structures. We further demonstrate the formation of a DXR-containing plastidial network around arbuscules, which is highly interconnected in the mature, functional state of the arbuscules. Our findings imply a functional role of a still unknown nature for the apocarotenoids or their respective carotenoid precursors in the arbuscular life cycle. PMID:14764905

  10. HOMOLOGY MODELLING AND BINDING SITE IDENTIFICATION OF 1DEOXY D-XYLULOSE 5 PHOSPHATE REDUCTOISOMERASE OF PLASMODIUM FALCIPARUM: NEW DRUG TARGET FOR PLSMODIUM FALCIPARUM

    Directory of Open Access Journals (Sweden)

    JYOTSNA CHOUBEY

    2010-08-01

    Full Text Available Malaria is major global health problem. Malaria parasite had developed resistance to the drug being used till date. It implies the development of new effective drug with different mode of action. Apicoplast in malaria and related parasite offer various new target for drug therapy[1]. Apicoplast contains various metabolic pathways that differ from those of host thereby presenting ideal strategies for drug therapy. Plasmodium falciparum 1deoxy- Dxylulose 5- phosphate reductoisomerase (pfDXR is a potential target for antimalarial chemotherapy. The three dimentional model (3D of this enzyme was determined by means of homology modeling through multiplealignment followed by intensive optimization and validation. The comparative modeling of pfDXPR was performed by using comparative modeling program MODELLER, Swiss Model, 3Djigsaw, and Geno3D.The modelling of the three dimensional structure of pfDXPR shows that models generated by Modeller were more acceptable in comparison to that by 3Djigsaw, Geno3D and Swiss Model. The obtained models were verified with the structure validation programs like, PROCHECK & Swiss pdb viewer was used for energy refinement of the model. SelfOptimized Prediction Method with Alignment (SOPMA is employed for calculating the secondary structural features of pfDXR protein sequences considered for this study. The secondary structure indicates whether a given amino acid lies in a helix, strand or coil. The results revealed that alpha helix dominated among secondary structure elements followed by random coils, extended strand and beta turns for all sequences. Active site determination through CASTp suggests that this protein can acts as potential drug target.

  11. Increased accumulation of the cardio-cerebrovascular disease treatment drug tanshinone in Salvia miltiorrhiza hairy roots by the enzymes 3-hydroxy-3-methylglutaryl CoA reductase and 1-deoxy-D-xylulose 5-phosphate reductoisomerase.

    Science.gov (United States)

    Shi, Min; Luo, Xiuqin; Ju, Guanhua; Yu, Xiaohong; Hao, Xiaolong; Huang, Qiang; Xiao, Jianbo; Cui, Lijie; Kai, Guoyin

    2014-09-01

    Tanshinone is widely used for treatment of cardio-cerebrovascular diseases with increasing demand. Herein, key enzyme genes SmHMGR (3-hydroxy-3-methylglutaryl CoA reductase) and SmDXR (1-deoxy-D-xylulose 5-phosphate reductoisomerase) involved in the tanshinone biosynthetic pathway were introduced into Salvia miltiorrhiza (Sm) hairy roots to enhance tanshinone production. Over-expression of SmHMGR or SmDXR in hairy root lines can significantly enhance the yield of tanshinone. Transgenic hairy root lines co-expressing HMGR and DXR (HD lines) produced evidently higher levels of total tanshinone (TT) compared with the control and single gene transformed lines. The highest tanshinone production was observed in HD42 with the concentration of 3.25 mg g(-1) DW. Furthermore, the transgenic hairy roots showed higher antioxidant activity than control. In addition, transgenic hairy root harboring HMGR and DXR (HD42) exhibited higher tanshinone content after elicitation by yeast extract and/or Ag(+) than before. Tanshinone can be significantly enhanced to 5.858, 6.716, and 4.426 mg g(-1) DW by YE, Ag(+), and YE-Ag(+) treatment compared with non-induced HD42, respectively. The content of cryptotanshinone and dihydrotanshinone was effectively elevated upon elicitor treatments, whereas there was no obvious promotion effect for the other two compounds tanshinone I and tanshinone IIA. Our results provide a useful strategy to improve tanshinone content as well as other natural active products by combination of genetic engineering with elicitors.

  12. Cloning and expression regulation of 1-deoxy-D-xylulose-5-phosphate reductoisomerase cDNA from Alpinia officinarum%高良姜1-脱氧-D-木酮糖5-磷酸还原异构酶cDNA克隆与表达调控

    Institute of Scientific and Technical Information of China (English)

    张春荣; 杨全; 陈虎彪; 庞玉新; 唐晓敏; 程轩轩; 吴文雅; 陈诗敏

    2012-01-01

    The rhizome of Alpinia officinarum is a widely used Chinese herbal medicine. The essential oil in A. officinarum rhizome is mainly composed of 1 , 8-cineole and other monoterpenes, as the major bioactive ingredients. In plants, monoterpenes are synthesized through the methylerythritol phosphate ( MEP) pathway in the plastids, and 1-deoxy-D-xylulose 5-phosphate reductoisomerase ( DXR) is an enzyme catalyzing a committed step of the MEP pathway. In the present study, the full-length cDNA encoding DXR was cloned from the rhizome of A. officinarum, using homology-based RT-PCR and rapid amplification of cDNA ends (RACE) techniques. The new cDNA was designated as AoDXR and submitted to GenBank to be assigned with an accession number HQ874658. The full-length cDNA of AoDXR was 1 670 bp containing a 1 419 bp open reading frame encoding a polypeptide of 472 amino acids with a calculated molecular mass of 51. 48 kDa and an isoelectric point of 6. 15. Bioinformatic analyses revealed that AoDXR showed extensive homology with DXRs from other plant species and contained a conserved plastids transit peptide, a Pro-rich region and two highly conserved NADPH-binding motifs in its N-terminal region characterized by all plant DXRs. The phylogenetic analysis revealed that AoDXR belonged to angiosperm DXRs. The structural modeling of AoDXR showed that AoDXR had the typical V-shaped structure of DXR proteins. The tissue expression pattern analysis indicated that AoDXR expressed strongly in leaves, weak in rhizomes of A. officinarum. Exogenous methyl jasmonate ( MeJA) could enhance the expression of AoDXR and the production of 1, 8-cineole in A. officinarum rhizomes. The cloning and characterization of AoDXR will be helpful to reveal the molecular regulation mechanism of monoterpene biosynthesis in A. officinarum and provides a candidate gene for metabolic engineering in improving the medicinal quality of A. officinarum rhizome.%目的:克隆高良姜1-脱氧-D-木酮糖5-磷酸还原

  13. Cloning and characterization of the 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway genes of a natural-rubber producing plant, Hevea brasiliensis.

    Science.gov (United States)

    Sando, Tomoki; Takeno, Shinya; Watanabe, Norie; Okumoto, Hiroshi; Kuzuyama, Tomohisa; Yamashita, Atsushi; Hattori, Masahira; Ogasawara, Naotake; Fukusaki, Eiichiro; Kobayashi, Akio

    2008-11-01

    Natural rubber is synthesized as rubber particles in the latex, the fluid cytoplasm of laticifers, of Hevea brasiliensis. Although it has been found that natural rubber is biosynthesized through the mevalonate pathway, the involvement of an alternative 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway is uncertain. We obtained all series of the MEP pathway candidate genes by analyzing expressed sequence tag (EST) information and degenerate PCR in H. brasiliensis. Complementation experiments with Escherichia coli mutants were performed to confirm the functions of the MEP pathway gene products of H. brasiliensis together with those of Arabidopsis thaliana, and it was found that 1-deoxy-D-xylulose-5-phosphate reductoisomerase, 2-C-methyl-D-erythritol 4-phosphate cytidylyltransferase, and 2-C-methyl-D-erythritol 2,4-cyclodiphosphate synthase of H. brasiliensis were functionally active in the E. coli mutants. Gene expression analysis revealed that the expression level of the HbDXS2 gene in latex was relatively high as compared to those of other MEP pathway genes. However, a feeding experiment with [1-(13)C] 1-deoxy-D-xylulose triacetate, an intermediate derivative of the MEP pathway, indicated that the MEP pathway is not involved in rubber biosynthesis, but is involved in carotenoids biosynthesis in H. brasiliensis.

  14. 烟草5-磷酸脱氧木酮糖还原异构酶基因(dxr)的克隆和表达分析%Cloning and Expression Analysis of 1-deoxy-D-xylulose-5-phosphate Reductoisomerases Gene (dxr) in Nicotina tabacum

    Institute of Scientific and Technical Information of China (English)

    朱晓宇; 王景; 赵二卫; 姚姗姗; 崔红

    2011-01-01

    以烟草(Nicotiana tabacum)栽培品种K326为材料,采用RT-PCR技术,克隆了萜类代谢关键酶烟草5-磷酸脱氧木酮糖还原异构酶(dxr)的cDNA片段.该基因编码区长1422 bp,编码473个氨基酸残基.利用Clustal W(1.82)和Bioedit软件,对烟草与番茄(Lycopersicon esculentum)、长春花(Catharanthus roseus)、金鱼草(A ntirrhinum majus)、薄荷(Mentha piperita)、玉米(Zea mays)、拟南芥(A rabidopsis thaliana)、念珠藻(Nostoc sp.)等物种dar基因的同源性进行分析,其氨基酸同源性分别达到93.6%、87.9%、86.3%、84.6%、84.2%、82.9%和53.5%.原核表达结果证明,该基因编码蛋白的分子量约为50 kD,与氨基酸序列估算相符合.组织表达特异性分析表明,dxr基因在烟草组织中的表达强弱为花>叶>茎>腺毛>种子>根,在花和叶片中的表达量占优势.该结果对烟草萜类代谢的分子调控和品质改良具有重要的参考价值.%Isoprenoid biosynthesis via mvalonate-independent pathway is very important to tobacco resistance and leaf quality. 1-deoxy-D-Xylulose-5-phosphate Reductoisomerases (dxr) is a key enzyme in biosynthesis of isopentenyl diphosphate, which is the precusor for monoterpenoid, diterpenoid and tetratepenoid compounds. To regulate the terpenoid metabolism pathway for tobacco improvement, some important genes such as dxr should be studied firstly. In this paper, dxr gene was cloned successfully from tobacco (Nicotiana tabacum) cultivar K326 leaf by RT-PCR. The cDNA code region was 1 422 bp long and encoding 437 amino acids. Sequence analysis by Clustal W declared that this fragment was highly homologous to dxr gene of other species. It shared 93.6% amino acid homologous to Lycopersicon esculentum, 87.9% to Catharanthus roseus, 86.3% to Antirrhinum majus,84.6% to Mentha piperita, 84.2% to Zea mays, 82.9% to Arabidopsis thaliana, and 53.5% to Nostoc sp.PCC7120. The expression vector pET21b-dxr was constructed and expressed in

  15. Differential Contribution of the First Two Enzymes of the MEP Pathway to the Supply of Metabolic Precursors for Carotenoid and Chlorophyll Biosynthesis in Carrot (Daucus carota)

    Science.gov (United States)

    Simpson, Kevin; Quiroz, Luis F.; Rodriguez-Concepción, Manuel; Stange, Claudia R.

    2016-01-01

    Carotenoids and chlorophylls are photosynthetic pigments synthesized in plastids from metabolic precursors provided by the methylerythritol 4-phosphate (MEP) pathway. The first two steps in the MEP pathway are catalyzed by the deoxyxylulose 5-phosphate synthase (DXS) and reductoisomerase (DXR) enzymes. While DXS has been recently shown to be the main flux-controlling step of the MEP pathway, both DXS and DXR enzymes have been proven to be able to promote an increase in MEP-derived products when overproduced in diverse plant systems. Carrot (Daucus carota) produces photosynthetic pigments (carotenoids and chlorophylls) in leaves and in light-exposed roots, whereas only carotenoids (mainly α- and β-carotene) accumulate in the storage root in darkness. To evaluate whether DXS and DXR activities influence the production of carotenoids and chlorophylls in carrot leaves and roots, the corresponding Arabidopsis thaliana genes were constitutively expressed in transgenic carrot plants. Our results suggest that DXS is limiting for the production of both carotenoids and chlorophylls in roots and leaves, whereas the regulatory role of DXR appeared to be minor. Interestingly, increased levels of DXS (but not of DXR) resulted in higher transcript abundance of endogenous carrot genes encoding phytoene synthase, the main rate-determining enzyme of the carotenoid pathway. These results support a central role for DXS on modulating the production of MEP-derived precursors to synthesize carotenoids and chlorophylls in carrot, confirming the pivotal relevance of this enzyme to engineer healthier, carotenoid-enriched products. PMID:27630663

  16. Metabolic engineering of essential oil yield and composition in mint by altering expression of deoxyxylulose phosphate reductoisomerase and menthofuran synthase

    OpenAIRE

    Mahmoud, Soheil S.; Croteau, Rodney B.

    2001-01-01

    Peppermint (Mentha × piperita L.) was independently transformed with a homologous sense version of the 1-deoxy-d-xylulose-5-phosphate reductoisomerase cDNA and with a homologous antisense version of the menthofuran synthase cDNA, both driven by the CaMV 35S promoter. Two groups of transgenic plants were regenerated in the reductoisomerase experiments, one of which remained normal in appearance and development; another was deficient in chlorophyll production and grew slowly. Transgenic plants ...

  17. Enzyme inhibitor studies reveal complex control of methyl-D-erythritol 4-phosphate (MEP pathway enzyme expression in Catharanthus roseus.

    Directory of Open Access Journals (Sweden)

    Mei Han

    Full Text Available In Catharanthus roseus, the monoterpene moiety exerts a strong flux control for monoterpene indole alkaloid (MIA formation. Monoterpene synthesis depends on the methyl-D-erythritol 4-phosphate (MEP pathway. Here, we have explored the regulation of this pathway in response to developmental and environmental cues and in response to specific enzyme inhibitors. For the MEP pathway entry enzyme 1-deoxy-D-xylulose 5-phosphate synthase (DXS, a new (type I DXS isoform, CrDXS1, has been cloned, which, in contrast to previous reports on type II CrDXS, was not transcriptionally activated by the transcription factor ORCA3. Regulation of the MEP pathway in response to metabolic perturbations has been explored using the enzyme inhibitors clomazone (precursor of 5-ketochlomazone, inhibitor of DXS and fosmidomycin (inhibitor of deoxyxylulose 5-phosphate reductoisomerase (DXR, respectively. Young leaves of non-flowering plants were exposed to both inhibitors, adopting a non-invasive in vivo technique. Transcripts and proteins of DXS (3 isoforms, DXR, and hydroxymethylbutenyl diphosphate synthase (HDS were monitored, and protein stability was followed in isolated chloroplasts. Transcripts for DXS1 were repressed by both inhibitors, whereas transcripts for DXS2A&B, DXR and HDS increased after clomazone treatment but were barely affected by fosmidomycin treatment. DXS protein accumulated in response to both inhibitors, whereas DXR and HDS proteins were less affected. Fosmidomycin-induced accumulation of DXS protein indicated substantial posttranscriptional regulation. Furthermore, fosmidomycin effectively protected DXR against degradation in planta and in isolated chloroplasts. Thus our results suggest that DXR protein stability may be affected by substrate binding. In summary, the present results provide novel insight into the regulation of DXS expression in C. roseus in response to MEP-pathway perturbation.

  18. Enzyme inhibitor studies reveal complex control of methyl-D-erythritol 4-phosphate (MEP) pathway enzyme expression in Catharanthus roseus.

    Science.gov (United States)

    Han, Mei; Heppel, Simon C; Su, Tao; Bogs, Jochen; Zu, Yuangang; An, Zhigang; Rausch, Thomas

    2013-01-01

    In Catharanthus roseus, the monoterpene moiety exerts a strong flux control for monoterpene indole alkaloid (MIA) formation. Monoterpene synthesis depends on the methyl-D-erythritol 4-phosphate (MEP) pathway. Here, we have explored the regulation of this pathway in response to developmental and environmental cues and in response to specific enzyme inhibitors. For the MEP pathway entry enzyme 1-deoxy-D-xylulose 5-phosphate synthase (DXS), a new (type I) DXS isoform, CrDXS1, has been cloned, which, in contrast to previous reports on type II CrDXS, was not transcriptionally activated by the transcription factor ORCA3. Regulation of the MEP pathway in response to metabolic perturbations has been explored using the enzyme inhibitors clomazone (precursor of 5-ketochlomazone, inhibitor of DXS) and fosmidomycin (inhibitor of deoxyxylulose 5-phosphate reductoisomerase (DXR)), respectively. Young leaves of non-flowering plants were exposed to both inhibitors, adopting a non-invasive in vivo technique. Transcripts and proteins of DXS (3 isoforms), DXR, and hydroxymethylbutenyl diphosphate synthase (HDS) were monitored, and protein stability was followed in isolated chloroplasts. Transcripts for DXS1 were repressed by both inhibitors, whereas transcripts for DXS2A&B, DXR and HDS increased after clomazone treatment but were barely affected by fosmidomycin treatment. DXS protein accumulated in response to both inhibitors, whereas DXR and HDS proteins were less affected. Fosmidomycin-induced accumulation of DXS protein indicated substantial posttranscriptional regulation. Furthermore, fosmidomycin effectively protected DXR against degradation in planta and in isolated chloroplasts. Thus our results suggest that DXR protein stability may be affected by substrate binding. In summary, the present results provide novel insight into the regulation of DXS expression in C. roseus in response to MEP-pathway perturbation.

  19. Metabolic engineering of essential oil yield and composition in mint by altering expression of deoxyxylulose phosphate reductoisomerase and menthofuran synthase.

    Science.gov (United States)

    Mahmoud, S S; Croteau, R B

    2001-07-17

    Peppermint (Mentha x piperita L.) was independently transformed with a homologous sense version of the 1-deoxy-d-xylulose-5-phosphate reductoisomerase cDNA and with a homologous antisense version of the menthofuran synthase cDNA, both driven by the CaMV 35S promoter. Two groups of transgenic plants were regenerated in the reductoisomerase experiments, one of which remained normal in appearance and development; another was deficient in chlorophyll production and grew slowly. Transgenic plants of normal appearance and growth habit expressed the reductoisomerase transgene strongly and constitutively, as determined by RNA blot analysis and direct enzyme assay, and these plants accumulated substantially more essential oil (about 50% yield increase) without change in monoterpene composition compared with wild-type. Chlorophyll-deficient plants did not afford detectable reductoisomerase mRNA or enzyme activity and yielded less essential oil than did wild-type plants, indicating cosuppression of the reductoisomerase gene. Plants transformed with the antisense version of the menthofuran synthase cDNA were normal in appearance but produced less than half of this undesirable monoterpene oil component than did wild-type mint grown under unstressed or stressed conditions. These experiments demonstrate that essential oil quantity and quality can be regulated by metabolic engineering. Thus, alteration of the committed step of the mevalonate-independent pathway for supply of terpenoid precursors improves flux through the pathway that leads to increased monoterpene production, and antisense manipulation of a selected downstream monoterpene biosynthetic step leads to improved oil composition.

  20. Liberia MEP WMS

    Data.gov (United States)

    US Agency for International Development — L-MEP WMS provides USAID, Implementing Partners, and L-MEP Staff the ability to view M view sector specific trend or base information; and answer questions about...

  1. Ketol-acid reductoisomerase enzymes and methods of use

    Energy Technology Data Exchange (ETDEWEB)

    Govindarajan, Sridhar; Li, Yougen; Liao, Der-Ing; O' Keefe, Daniel P.; Minshull, Jeremy Stephen; Rothman, Steven Cary; Tobias, Alexander Vincent

    2015-10-27

    Provided herein are polypeptides having ketol-aid reductoisomerase activity as well as microbial host cells comprising such polypeptides. Polypeptides provided herein may be used in biosynthetic pathways, including, but not limited to, isobutanol biosynthetic pathways.

  2. 1-Deoxy-D-xylulose-5-phosphate synthase, a limiting enzyme for plastidic isoprenoid biosynthesis in plants.

    Science.gov (United States)

    Estévez, J M; Cantero, A; Reindl, A; Reichler, S; León, P

    2001-06-22

    The initial step of the plastidic 2C-methyl-D-erythritol 4-phosphate (MEP) pathway that produces isopentenyl diphosphate is catalyzed by 1-deoxy-d-xylulose-5-phosphate synthase. To investigate whether or not 1-deoxy-d-xylulose-5-phosphate synthase catalyzes a limiting step in the MEP pathway in plants, we produced transgenic Arabidopsis plants that over- or underexpress this enzyme. Compared with non-transgenic wild-type plants, the transgenic plants accumulate different levels of various isoprenoids such as chlorophylls, tocopherols, carotenoids, abscisic acid, and gibberellins. Phenotypically, the transgenic plants had slight alterations in growth and germination rates. Because the levels of several plastidic isoprenoids correlate with changes in 1-deoxy-D-xylulose-5-phosphate synthase levels, we conclude that this enzyme catalyzes one of the rate-limiting steps of the MEP biosynthetic pathway. Furthermore, since the product of the MEP pathway is isopentenyl diphosphate, our results suggest that in plastids the pool of isopentenyl diphosphate is limiting to isprenoid production.

  3. Genetics Home Reference: pyridoxal 5'-phosphate-dependent epilepsy

    Science.gov (United States)

    ... 5'-phosphate-dependent epilepsy pyridoxal 5'-phosphate-dependent epilepsy Enable Javascript to view the expand/collapse boxes. ... All Close All Description Pyridoxal 5'-phosphate-dependent epilepsy is a condition that involves seizures beginning soon ...

  4. Regulation of resin acid synthesis in Pinus densiflora by differential transcription of genes encoding multiple 1-deoxy-D-xylulose 5-phosphate synthase and 1-hydroxy-2-methyl-2-(E)-butenyl 4-diphosphate reductase genes.

    Science.gov (United States)

    Kim, Yeon-Bok; Kim, Sang-Min; Kang, Min-Kyoung; Kuzuyama, Tomohisa; Lee, Jong Kyu; Park, Seung-Chan; Shin, Sang-Chul; Kim, Soo-Un

    2009-05-01

    Pinus densiflora Siebold et Zucc. is the major green canopy species in the mountainous area of Korea. To assess the response of resin acid biosynthetic genes to mechanical and chemical stimuli, we cloned cDNAs of genes encoding enzymes involved in the 2-C-methyl-d-erythritol 4-phosphate (MEP) pathway (1-deoxy-d-xylulose 5-phosphate synthase (PdDXS), 1-deoxy-d-xylulose 5-phosphate reductoisomerase (PdDXR) and 1-hydroxy-2-methyl-2-(E)-butenyl 4-diphosphate reductase (PdHDR)) by the rapid amplification of cDNA ends (RACE) technique. In addition, we cloned the gene encoding abietadiene synthase (PdABS) as a marker for the site of pine resin biosynthesis. PdHDR and PdDXS occurred as two gene families. In the phylogenetic trees, PdDXSs, PdDXR and PdHDRs each formed a separate clade from their respective angiosperm homologs. PdDXS2, PdHDR2 and PdDXR were most actively transcribed in stem wood, whereas PdABS was specifically transcribed. The abundance of PdDXS2 transcripts in wood in the resting state was generally 50-fold higher than the abundance of PdDXS1 transcripts, and PdHDR2 transcripts were more abundant by an order of magnitude in wood than in other tissues, with the ratio of PdHDR2 to PdHDR1 transcripts in wood being about 1. Application of 1 mM methyl jasmonate (MeJA) selectively enhanced the transcript levels of PdDXS2 and PdHDR2 in wood. The ratios of PdDXS2 to PdDXS1 and PdHDR2 to PdHDR1 reached 900 and 20, respectively, on the second day after MeJA treatment, whereas the transcript level of PdABS increased twofold by 3 days after MeJA treatment. Wounding of the stem differentially enhanced the transcript ratios of PdDXS2 to PdDXS1 and PdHDR2 to PdHDR1 to 300 and 70, respectively. The increase in the transcript levels of the MEP pathway genes in response to wounding was accompanied by two orders of magnitude increase in PdABS transcripts. These observations indicated that resin acid biosynthesis activity, represented by PdABS transcription, was correlated

  5. 21 CFR 582.5697 - Riboflavin-5-phosphate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Riboflavin-5-phosphate. 582.5697 Section 582.5697 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5697 Riboflavin-5-phosphate. (a) Product. Riboflavin-5-phosphate. (b) Conditions of...

  6. Pyridoxal-5'-phosphate-dependent catalytic antibodies.

    Science.gov (United States)

    Gramatikova, Svetlana; Mouratou, Barbara; Stetefeld, Jörg; Mehta, Perdeep K; Christen, Philipp

    2002-11-01

    Strategies for expanding the catalytic scope of antibodies include the incorporation of inorganic or organic cofactors into their binding sites. An obvious choice is pyridoxal-5'-phosphate (PLP), which is probably the most versatile organic cofactor of enzymes. Monoclonal antibodies against the hapten N(alpha)-(5'-phosphopyridoxyl)-L-lysine, a stable analog of the covalent coenzyme-substrate adducts were screened by a competition ELISA for binding of the PLP-amino acid Schiff base adduct. The Schiff base with its C4'-N alpha double bond is, in contrast to the hapten, a planar compound and is an obligatory intermediate in all PLP-dependent reactions of amino acids. This highly discriminating screening step eliminated all but 5 of 24 hapten-binding antibodies. The five remaining antibodies were tested for catalysis of the PLP-dependent alpha,beta-elimination reaction of beta-chloroalanine. Antibody 15A9 complied with this selection criterion and catalyzed in addition the cofactor-dependent transamination reaction of hydrophobic D-amino acids and oxo acids (k(cat)'=0.42 min(-1) with D-alanine at 25 degrees C). Homology modeling together with alanine scanning yielded a 3D model of Fab 15A9. The striking analogy between antibody 15A9 and PLP-dependent enzymes includes the following features: (1) The binding sites accommodate the planar coenzyme-amino acid adduct. (2) The bond at C alpha to be broken lies together with the C alpha-N bond in a plane orthogonal to the plane of coenzyme and imine bond. (3) The alpha-carboxylate group of the substrate is bound by an arginine residue. (4) The coenzyme-substrate adduct assumes a cisoid conformation. (5) PLP markedly contributes to catalytic efficiency, being a 10(4) times more efficient amino group acceptor than pyruvate. The protein moiety, however, ensures reaction as well as substrate specificity, and further accelerates the reaction (in 15A9 k(cat (Ab x PLP))'/k(cat (PLP))'=5 x 10(3)). The analogies of antibody 15A9 with

  7. 3-substituted anilines as scaffolds for the construction of glutamine synthetase and DXP-reductoisomerase inhibitors

    CSIR Research Space (South Africa)

    Mutorwa, M

    2009-01-01

    Full Text Available -1 Synthetic Communications Volume 39, Issue 15, 2009 3-Substituted Anilines as Scaffolds for the Construction of Glutamine Synthetase and DXP-Reductoisomerase Inhibitors Marius Mutorwaa, Sheriff Salisua, Gregory L. Blatchbc, Colin Kenyond & Perry T...

  8. Mathematical modelling of the diurnal regulation of the MEP pathway in Arabidopsis.

    Science.gov (United States)

    Pokhilko, Alexandra; Bou-Torrent, Jordi; Pulido, Pablo; Rodríguez-Concepción, Manuel; Ebenhöh, Oliver

    2015-05-01

    Isoprenoid molecules are essential elements of plant metabolism. Many important plant isoprenoids, such as chlorophylls, carotenoids, tocopherols, prenylated quinones and hormones are synthesised in chloroplasts via the 2-C-methyl-d-erythritol 4-phosphate (MEP) pathway. Here we develop a mathematical model of diurnal regulation of the MEP pathway in Arabidopsis thaliana. We used both experimental and theoretical approaches to integrate mechanisms potentially involved in the diurnal control of the pathway. Our data show that flux through the MEP pathway is accelerated in light due to the photosynthesis-dependent supply of metabolic substrates of the pathway and the transcriptional regulation of key biosynthetic genes by the circadian clock. We also demonstrate that feedback regulation of both the activity and the abundance of the first enzyme of the MEP pathway (1-deoxy-D-xylulose 5-phosphate synthase, DXS) by pathway products stabilizes the flux against changes in substrate supply and adjusts the flux according to product demand under normal growth conditions. These data illustrate the central relevance of photosynthesis, the circadian clock and feedback control of DXS for the diurnal regulation of the MEP pathway.

  9. Development of Antibacterials Targeting the MEP Pathway of Select Agents

    Science.gov (United States)

    2015-03-01

    both MEP synthase and MEP cytidylyltransferase. 15. SUBJECT TERMS Enzymology, MEP pathway, bacteria, isoprene, drug discovery , antibiotics, screening ...Figure 2. Schematic of the approach to performing the high - throughput screen with IspC. 6 recombinant Mycobacterium tuberculosis MEP Synthase and the...underway. MEP Cytidylyltransferase (IspD) As illustrated in Figure 4, we have also performed a high - throughput screen with the Francisella tularensis MEP

  10. Reconciling Medical Expenditure Estimates from the MEPS...

    Data.gov (United States)

    U.S. Department of Health & Human Services — Reconciling Medical Expenditure Estimates from the MEPS and NHEA, 2007, published in Volume 2, Issue 4 of the Medicare and Medicaid Research Review, provides a...

  11. SDE Plus, SDE and MEP. Annual review 2012; SDE+, SDE en MEP. Jaarbericht 2012

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-05-15

    This annual report describes the applications for SDE subsidy (renewable energy support scheme) in the period 2008-2012, the new SDE Plus which starts in 2013, and the MEP transition scheme (MEP stands for 'Environmental quality of electricity production', predecessor of SDE for the period 2003-2006) and applications from the MEP scheme [Dutch] Het jaarbericht 2012 voor de SDE+, SDE en MEP presenteert de resultaten van de regeling Stimulering Duurzame Energieproductie (SDE+ vanaf 2013 en SDE, 2008-2012) en de voorganger van de SDE, de subsidieregeling Milieukwaliteit van de Elektriciteitsproductie.

  12. SDE Plus, SDE and MEP. Annual review 2012; SDE+, SDE en MEP. Jaarbericht 2012

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-05-15

    This annual report describes the applications for SDE subsidy (renewable energy support scheme) in the period 2008-2012, the new SDE Plus which starts in 2013, and the MEP transition scheme (MEP stands for 'Environmental quality of electricity production', predecessor of SDE for the period 2003-2006) and applications from the MEP scheme [Dutch] Het jaarbericht 2012 voor de SDE+, SDE en MEP presenteert de resultaten van de regeling Stimulering Duurzame Energieproductie (SDE+ vanaf 2013 en SDE, 2008-2012) en de voorganger van de SDE, de subsidieregeling Milieukwaliteit van de Elektriciteitsproductie.

  13. Ribose 5-Phosphate Isomerase Investigations for the Undergraduate Biochemistry Laboratory

    Science.gov (United States)

    Jewett, Kathy; Sandwick, Roger K.

    2011-01-01

    The enzyme ribose 5-phosphate isomerase (RpiA) has many features that make it attractive as a focal point of a semester-long, advanced biochemistry laboratory for undergraduate students. The protein can easily and inexpensively be isolated from spinach using traditional purification techniques. Characterization of RpiA enzyme activity can be…

  14. Four Thruster Microfluidic Electrospray Propulsion (MEP) Cubesat Board Demonstration Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Cubesat Microfluidic Electrospray Propulsion (MEP) system module prototype will be designed, built and tested to demonstrate that a four MEP thruster system can...

  15. Morton's foot and pyridoxal 5'-phosphate deficiency: genetically linked traits.

    Science.gov (United States)

    Nichols, Trent W; Gaiteri, Christopher

    2014-12-01

    Vitamin B6 is an essential vitamin needed for many chemical reactions in the human body. It exists as several vitamins forms but pyridoxal 5'-phosphate (PLP) is the phosphorylated form needed for transamination, deamination, and decarboxylation. PLP is important in the production of neurotransmitters, acts as a Schiff base and is essential in the metabolism of homocysteine, a toxic amino acid involved in cardiovascular disease, stroke, thrombotic and Alzheimer's disease. This report announces the connection between a deficit of PLP with a genetically linked physical foot form known as the Morton's foot. Morton's foot has been associated with fibromyalgia/myofascial pain syndrome. Another gene mutation methylenetetrahydrofolate reductase (MTHFr) is now being recognized much commonly than previous with chronic fatigue, chronic Lyme diseases and as "the missing link" in other chronic diseases. PLP deficiency also plays a role in impaired glucose tolerance and may play a much bigger role in the obesity, diabetes, fatty liver and metabolic syndrome. Without the Schiff-base of PLP acting as an electron sink, storing electrons and dispensing them in the mitochondria, free radical damage occurs! The recognition that a phenotypical expression (Morton's foot) of a gene resulting in deficiency of an important cofactor enzyme pyridoxal 5'-phosphate will hopefully alert physicians and nutritionist to these phenomena. Supplementation with PLP, L5-MTHF, B12 and trimethylglycine should be used in those patients with hyperhomocysteinemia and/or MTHFR gene mutation.

  16. Inactive mutants of human pyridoxine 5'-phosphate oxidase: a possible role for a noncatalytic pyridoxal 5'-phosphate tight binding site.

    Science.gov (United States)

    Ghatge, Mohini S; Karve, Sayali S; David, Tanya M S; Ahmed, Mostafa H; Musayev, Faik N; Cunningham, Kendra; Schirch, Verne; Safo, Martin K

    2016-05-01

    Pyridoxal 5'-phosphate (PLP) is a cofactor for many vitamin B6-requiring enzymes that are important for the synthesis of neurotransmitters. Pyridoxine 5'-phosphate oxidase (PNPO) is one of two enzymes that produce PLP. Some 16 known mutations in human PNPO (hPNPO), including R95C and R229W, lead to deficiency of PLP in the cell and have been shown to cause neonatal epileptic encephalopathy (NEE). This disorder has no effective treatment, and is often fatal unless treated with PLP. In this study, we show that R95C hPNPO exhibits a 15-fold reduction in affinity for the FMN cofactor, a 71-fold decrease in affinity for the substrate PNP, a 4.9-fold decrease in specific activity, and a 343-fold reduction in catalytic activity, compared to the wild-type enzyme. We have reported similar findings for R229W hPNPO. This report also shows that wild-type, R95C and R229W hPNPO bind PLP tightly at a noncatalytic site and transfer it to activate an apo-B6 enzyme into the catalytically active holo-form. We also show for the first time that hPNPO forms specific interactions with several B6 enzymes with dissociation constants ranging from 0.3 to 12.3 μm. Our results suggest a possible in vivo role for the tight binding of PLP in hPNPO, whether wild-type or variant, by protecting the very reactive PLP, and transferring this PLP directly to activate apo-B6 enzymes.

  17. Molecular design, synthesis and biological activities of amidines as new ketol-acid reductoisomerase inhibitors

    Institute of Scientific and Technical Information of China (English)

    Bao Lei Wang; Yong Hong Li; Jian Guo Wang; Yi Ma; Zheng Ming Li

    2008-01-01

    Diamidine (A) was identified in our in vitro bio-assay as a possible inhibitor of ketol-acid reductoisomerase (KARI) from the ACD database search based on the known three-dimensional crystal structure of KARI. An investigation on interaction of A on KARI active sites, led to the design and synthesis of 15 novel monoamidines. Some of those showed better biological activity than A on rice KARI (in vitro) and in greenhouse herbicidal tests (in vivo). The structure-biological activity relationship was investigated, which provides valuable information to further study of potential KARI inhibitors.

  18. Development of Antibacterials Targeting the MEP Pathway of Select Agents

    Science.gov (United States)

    2014-05-01

    chemical class of antimicrobial drugs targeting MEP synthase. Additionally, our screening has highlighted a rationally designed bisubstrate inhibitor of...identify top compounds. • Mode of inhibition studies to determine the mechanism of action for the top hit compounds. • Identification of a...chemical class of antimicrobial drugs targeting MEP synthase. Additionally, our screening has highlighted a rationally designed bisubstrate inhibitor of

  19. A MEPS is a MEPS is a MEPS. Comparing Ecodesign and Top Runner schemes for setting product efficiency standards

    Energy Technology Data Exchange (ETDEWEB)

    Siderius, P.J.S. [NL Agency, Croeselaan 15, P.O. Box 8242, 3503 RE Utrecht (Netherlands); Nakagami, H. [Jyukankyo Research Institute, 3-29, Kioi-cho, Chiyoda-ku Tokyo, 102-0094 (Japan)

    2013-02-15

    Both Top Runner in Japan and Ecodesign in the European Union are schemes to set requirements on the energy efficiency (minimum efficiency performance standards, MEPS) of a variety of products. This article provides an overview of the main characteristics and results of both schemes and gives recommendations for improving them. Both schemes contribute significantly to the energy efficiency targets set by the European Commission and the Japanese government. Although it is difficult to compare the absolute levels of the requirements, comparison of the relative improvements and of the savings on household electricity consumption (11 % in Japan, 16 % in the EU) suggest they are in the same range. Furthermore, the time needed to set or review requirements is in both schemes considerable (between 5 and 6 years on average) and the manageability increasingly will become a challenge. The appeal of the Top Runner approach is that the most efficient product (Top Runner) sets the standard for all products at the next target year. Although the Ecodesign scheme includes the elements for a Top Runner approach, it could exploit this principle more explicitly. On the other hand, the Top Runner scheme could benefit by using a real minimum efficiency performance standard instead of a fleet average. This would make the monitoring and enforcement more simple and transparent, and would open the scheme for products where the market situation is less clear.

  20. Molecular cloning, functional characterization and expression of potato (Solanum tuberosum) 1-deoxy-d-xylulose 5-phosphate synthase 1 (StDXS1) in response to Phytophthora infestans.

    Science.gov (United States)

    Henriquez, Maria Antonia; Soliman, Atta; Li, Genyi; Hannoufa, Abdelali; Ayele, Belay T; Daayf, Fouad

    2016-02-01

    1-Deoxy-D-xylulose 5-phosphate synthase (DXS) catalyzes the initial step of the plastidial 2C-methyl-D-erythritol-4-phosphate (DOXP-MEP) pathway involved in isoprenoid biosynthesis. In this study, we cloned the complete cDNA of potato DXS gene that was designated StDXS1. StDXS1 cDNA encodes for 719 amino acid residues, with MW of 77.8 kDa, and is present in one copy in the potato genome. Phylogenetic analysis and protein sequence alignments assigned StDXS1 to a group with DXS homologues from closely related species and exhibited homodomain identity with known DXS proteins from other plant species. Late blight symptoms occurred in parallel with a reduction in StDXS1 transcript levels, which may be associated with the levels of isoprenoids that contribute to plant protection against pathogens. Subcellular localization indicated that StDXS1 targets the chloroplasts where isoprenoids are synthesized. Arabidopsis expressing StDXS1 showed a higher accumulation of carotenoids and chlorophyll as compared to wild type controls. Lower levels of ABA and GA were detected in the transgenic DXS lines as compared to control plants, which reflected on higher germination rates of the transgenic DXS lines. No changes were detected in JA or SA contents. Selected downstream genes in the DOXP-MEP pathway, especially GGPPS genes, were up-regulated in the transgenic lines.

  1. Conversion of D-ribulose 5-phosphate to D-xylulose 5-phosphate : new insights from structural and biochemical studies on human RPE.

    Energy Technology Data Exchange (ETDEWEB)

    Liang, W.; Ouyang, S.; Shaw, N.; Joachimiak, A.; Zhang, R.; Liu, Z.; Biosciences Division; Chinese Academy of Sciences

    2011-02-01

    The pentose phosphate pathway (PPP) confers protection against oxidative stress by supplying NADPH necessary for the regeneration of glutathione, which detoxifies H{sub 2}O{sub 2} into H{sub 2}O and O{sub 2}. RPE functions in the PPP, catalyzing the reversible conversion of D-ribulose 5-phosphate to D-xylulose 5-phosphate and is an important enzyme for cellular response against oxidative stress. Here, using structural, biochemical, and functional studies, we show that human D-ribulose 5-phosphate 3-epimerase (hRPE) uses Fe{sup 2+} for catalysis. Structures of the binary complexes of hRPE with D-ribulose 5-phosphate and D-xylulose 5-phosphate provide the first detailed molecular insights into the binding mode of physiological ligands and reveal an octahedrally coordinated Fe{sup 2+} ion buried deep inside the active site. Human RPE folds into a typical ({beta}/{alpha}){sub 8} triosephosphate isomerase (TIM) barrel with a loop regulating access to the active site. Two aspartic acids are well positioned to carry out the proton transfers in an acid-base type of reaction mechanism. Interestingly, mutating Ser-10 to alanine almost abolished the enzymatic activity, while L12A and M72A mutations resulted in an almost 50% decrease in the activity. The binary complexes of hRPE reported here will aid in the design of small molecules for modulating the activity of the enzyme and altering flux through the PPP.

  2. Conversion of D-ribulose 5-phosphate to D-xylulose 5-phosphate: new insights from structural and biochemical studies on human RPE.

    Science.gov (United States)

    Liang, Wenguang; Ouyang, Songying; Shaw, Neil; Joachimiak, Andrzej; Zhang, Rongguang; Liu, Zhi-Jie

    2011-02-01

    The pentose phosphate pathway (PPP) confers protection against oxidative stress by supplying NADPH necessary for the regeneration of glutathione, which detoxifies H(2)O(2) into H(2)O and O(2). RPE functions in the PPP, catalyzing the reversible conversion of D-ribulose 5-phosphate to D-xylulose 5-phosphate and is an important enzyme for cellular response against oxidative stress. Here, using structural, biochemical, and functional studies, we show that human D-ribulose 5-phosphate 3-epimerase (hRPE) uses Fe(2+) for catalysis. Structures of the binary complexes of hRPE with D-ribulose 5-phosphate and D-xylulose 5-phosphate provide the first detailed molecular insights into the binding mode of physiological ligands and reveal an octahedrally coordinated Fe(2+) ion buried deep inside the active site. Human RPE folds into a typical (β/α)(8) triosephosphate isomerase (TIM) barrel with a loop regulating access to the active site. Two aspartic acids are well positioned to carry out the proton transfers in an acid-base type of reaction mechanism. Interestingly, mutating Ser-10 to alanine almost abolished the enzymatic activity, while L12A and M72A mutations resulted in an almost 50% decrease in the activity. The binary complexes of hRPE reported here will aid in the design of small molecules for modulating the activity of the enzyme and altering flux through the PPP.

  3. Ribose 5-phosphate isomerase B knockdown compromises Trypanosoma brucei bloodstream form infectivity.

    Science.gov (United States)

    Loureiro, Inês; Faria, Joana; Clayton, Christine; Macedo-Ribeiro, Sandra; Santarém, Nuno; Roy, Nilanjan; Cordeiro-da-Siva, Anabela; Tavares, Joana

    2015-01-01

    Ribose 5-phosphate isomerase is an enzyme involved in the non-oxidative branch of the pentose phosphate pathway, and catalyzes the inter-conversion of D-ribose 5-phosphate and D-ribulose 5-phosphate. Trypanosomatids, including the agent of African sleeping sickness namely Trypanosoma brucei, have a type B ribose-5-phosphate isomerase. This enzyme is absent from humans, which have a structurally unrelated ribose 5-phosphate isomerase type A, and therefore has been proposed as an attractive drug target waiting further characterization. In this study, Trypanosoma brucei ribose 5-phosphate isomerase B showed in vitro isomerase activity. RNAi against this enzyme reduced parasites' in vitro growth, and more importantly, bloodstream forms infectivity. Mice infected with induced RNAi clones exhibited lower parasitaemia and a prolonged survival compared to control mice. Phenotypic reversion was achieved by complementing induced RNAi clones with an ectopic copy of Trypanosoma cruzi gene. Our results present the first functional characterization of Trypanosoma brucei ribose 5-phosphate isomerase B, and show the relevance of an enzyme belonging to the non-oxidative branch of the pentose phosphate pathway in the context of Trypanosoma brucei infection.

  4. Complexes of vitamin B6XX: equilibrium and mechanistic studies of the reaction of pyridoxal-5'-phosphate with pyridoxamine-5'-phosphate in the presence of copper(II).

    Science.gov (United States)

    Marafie, H M; el-Ezaby, M S; Fareed, S

    1989-09-01

    The interaction of Cu(II) with pyridoxamine-5'-phosphate (PMP) and pyridoxal-5'-phosphate (PLP) was studied potentiometrically. The titration data were assessed by MINIQUAD program. Several protonated and nonprotonated complexes have been found to exist in solution. The reaction of PLP with Cu(II)-PMP has been studied kinetically, using the stopped-flow technique. Two rate steps have been observed. The first step has been attributed to the formation of a Schiff's base metal complex. The second step may be due to the formation of a ternary complex formation. A mechanism was suggested.

  5. Medical Expenditure Panel Survey (MEPS) Summary Data Tables

    Data.gov (United States)

    U.S. Department of Health & Human Services — Summary Data Tables Data collected through MEPS are used to generate tables with frequently used summary statistics. These tables are available here for both the...

  6. Rv2607 from Mycobacterium tuberculosis is a pyridoxine 5'-phosphate oxidase with unusual substrate specificity.

    Directory of Open Access Journals (Sweden)

    Ellene H Mashalidis

    Full Text Available Despite intensive effort, the majority of the annotated Mycobacterium tuberculosis genome consists of genes encoding proteins of unknown or poorly understood function. For example, there are seven conserved hypothetical proteins annotated as homologs of pyridoxine 5'-phosphate oxidase (PNPOx, an enzyme that oxidizes pyridoxine 5'-phosphate (PNP or pyridoxamine 5'-phosphate (PMP to form pyridoxal 5'-phosphate (PLP. We have characterized the function of Rv2607 from Mycobacterium tuberculosis H37Rv and shown that it encodes a PNPOx that oxidizes PNP to PLP. The k(cat and K(M for this reaction were 0.01 s(-1 and 360 µM, respectively. Unlike many PNPOx enzymes, Rv2607 does not recognize PMP as a substrate.

  7. Host cells and methods for producing 1-deoxyxylulose 5-phosphate (DXP) and/or a DXP derived compound

    Science.gov (United States)

    Kirby, James; Fortman, Jeffrey L.; Nishimoto, Minobu; Keasling, Jay D.

    2016-07-05

    The present invention provides for a genetically modified host cell capable of producing 1-deoxyxylulose 5-phosphate or 1-deoxy-D-xylulose 5-phosphate (DXP) (12), and optionally one or more DXP derived compounds, comprising: (a) a mutant RibB, or functional variant thereof, capable of catalyzing xylulose 5-phosphate and/or ribulose 5-phosphate to DXP, or (b) a YajO, or functional variant thereof, and a XylB, or functional variant thereof.

  8. Identification of a d-Arabinose-5-Phosphate Isomerase in the Gram-Positive Clostridium tetani.

    Science.gov (United States)

    Cech, David L; Markin, Katherine; Woodard, Ronald W

    2017-09-01

    d-Arabinose-5-phosphate (A5P) isomerases (APIs) catalyze the interconversion of d-ribulose-5-phosphate and d-arabinose-5-phosphate. Various Gram-negative bacteria, such as the uropathogenic Escherichia coli strain CFT073, contain multiple API paralogs (KdsD, GutQ, KpsF, and c3406) that have been assigned various cellular functions. The d-arabinose-5-phosphate formed by these enzymes seems to play important roles in the biosynthesis of lipopolysaccharide (LPS) and group 2 K-antigen capsules, as well as in the regulation of the cellular d-glucitol uptake and uropathogenic infectivity/virulence. The genome of a Gram-positive pathogenic bacterium, Clostridium tetani, contains a gene encoding a putative API, C. tetani API (CtAPI), even though C. tetani lacks both LPS and capsid biosynthetic genes. To better understand the physiological role of d-arabinose-5-phosphate in this Gram-positive organism, recombinant CtAPI was purified and characterized. CtAPI displays biochemical characteristics similar to those of APIs from Gram-negative organisms and complements the API deficiency of an E. coli API knockout strain. Thus, CtAPI represents the first d-arabinose-5-phosphate isomerase to be identified and characterized from a Gram-positive bacterium.IMPORTANCE The genome of Clostridium tetani, a pathogenic Gram-positive bacterium and the causative agent of tetanus, contains a gene (the CtAPI gene) that shares high sequence similarity with those of genes encoding d-arabinose-5-phosphate isomerases. APIs play an important role within Gram-negative bacteria in d-arabinose-5-phosphate production for lipopolysaccharide biosynthesis, capsule formation, and regulation of cellular d-glucitol uptake. The significance of our research is in identifying and characterizing CtAPI, the first Gram-positive API. Our findings show that CtAPI is specific to the interconversion of arabinose-5-phosphate and ribulose-5-phosphate while having no activity with the other sugars and sugar phosphates

  9. Structural basis for Mep2 ammonium transceptor activation by phosphorylation.

    Science.gov (United States)

    van den Berg, Bert; Chembath, Anupama; Jefferies, Damien; Basle, Arnaud; Khalid, Syma; Rutherford, Julian C

    2016-04-18

    Mep2 proteins are fungal transceptors that play an important role as ammonium sensors in fungal development. Mep2 activity is tightly regulated by phosphorylation, but how this is achieved at the molecular level is not clear. Here we report X-ray crystal structures of the Mep2 orthologues from Saccharomyces cerevisiae and Candida albicans and show that under nitrogen-sufficient conditions the transporters are not phosphorylated and present in closed, inactive conformations. Relative to the open bacterial ammonium transporters, non-phosphorylated Mep2 exhibits shifts in cytoplasmic loops and the C-terminal region (CTR) to occlude the cytoplasmic exit of the channel and to interact with His2 of the twin-His motif. The phosphorylation site in the CTR is solvent accessible and located in a negatively charged pocket ∼30 Å away from the channel exit. The crystal structure of phosphorylation-mimicking Mep2 variants from C. albicans show large conformational changes in a conserved and functionally important region of the CTR. The results allow us to propose a model for regulation of eukaryotic ammonium transport by phosphorylation.

  10. The malarial drug target Plasmodium falciparum 1-deoxy-D-xylulose-5-phosphate reductoisomerase (PfDXR): development of a 3-D model for identification of novel, structural and functional features and for inhibitor screening.

    Science.gov (United States)

    Goble, Jessica L; Adendorff, Matthew R; de Beer, Tjaart A P; Stephens, Linda L; Blatch, Gregory L

    2010-01-01

    A three-dimensional model of the malarial drug target protein PfDXR was generated, and validated using structure-checking programs and protein docking studies. Structural and functional features unique to PfDXR were identified using the model and comparative sequence analyses with apicomplexan and non-apicomplexan DXR proteins. Furthermore, we have used the model to develop an efficient approach to screen for potential tool compounds for use in the rational design of novel DXR inhibitors.

  11. Engineering of Recombinant Poplar Deoxy-D-Xylulose-5-Phosphate Synthase (PtDXS) by Site-Directed Mutagenesis Improves Its Activity

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    Banerjee, Aparajita; Preiser, Alyssa L.

    2016-01-01

    Deoxyxylulose 5-phosphate synthase (DXS), a thiamine diphosphate (ThDP) dependent enzyme, plays a regulatory role in the methylerythritol 4-phosphate (MEP) pathway. Isopentenyl diphosphate (IDP) and dimethylallyl diphosphate (DMADP), the end products of this pathway, inhibit DXS by competing with ThDP. Feedback inhibition of DXS by IDP and DMADP constitutes a significant metabolic regulation of this pathway. The aim of this work was to experimentally test the effect of key residues of recombinant poplar DXS (PtDXS) in binding both ThDP and IDP. This work also described the engineering of PtDXS to improve the enzymatic activity by reducing its inhibition by IDP and DMADP. We have designed and tested modifications of PtDXS in an attempt to reduce inhibition by IDP. This could possibly be valuable by removing a feedback that limits the usefulness of the MEP pathway in biotechnological applications. Both ThDP and IDP use similar interactions for binding at the active site of the enzyme, however, ThDP being a larger molecule has more anchoring sites at the active site of the enzyme as compared to the inhibitors. A predicted enzyme structure was examined to find ligand-enzyme interactions, which are relatively more important for inhibitor-enzyme binding than ThDP-enzyme binding, followed by their modifications so that the binding of the inhibitors can be selectively affected compared to ThDP. Two alanine residues important for binding ThDP and the inhibitors were mutated to glycine. In two of the cases, both the IDP inhibition and the overall activity were increased. In another case, both the IDP inhibition and the overall activity were reduced. This provides proof of concept that it is possible to reduce the feedback from IDP on DXS activity. PMID:27548482

  12. Molecular basis of reduced pyridoxine 5'-phosphate oxidase catalytic activity in neonatal epileptic encephalopathy disorder.

    Science.gov (United States)

    Musayev, Faik N; Di Salvo, Martino L; Saavedra, Mario A; Contestabile, Roberto; Ghatge, Mohini S; Haynes, Alexina; Schirch, Verne; Safo, Martin K

    2009-11-06

    Mutations in pyridoxine 5'-phosphate oxidase are known to cause neonatal epileptic encephalopathy. This disorder has no cure or effective treatment and is often fatal. Pyridoxine 5'-phosphate oxidase catalyzes the oxidation of pyridoxine 5'-phosphate to pyridoxal 5'-phosphate, the active cofactor form of vitamin B(6) required by more than 140 different catalytic activities, including enzymes involved in amino acid metabolism and biosynthesis of neurotransmitters. Our aim is to elucidate the mechanism by which a homozygous missense mutation (R229W) in the oxidase, linked to neonatal epileptic encephalopathy, leads to reduced oxidase activity. The R229W variant is approximately 850-fold less efficient than the wild-type enzyme due to an approximately 192-fold decrease in pyridoxine 5'-phosphate affinity and an approximately 4.5-fold decrease in catalytic activity. There is also an approximately 50-fold reduction in the affinity of the R229W variant for the FMN cofactor. A 2.5 A crystal structure of the R229W variant shows that the substitution of Arg-229 at the FMN binding site has led to a loss of hydrogen-bond and/or salt-bridge interactions between FMN and Arg-229 and Ser-175. Additionally, the mutation has led to an alteration of the configuration of a beta-strand-loop-beta-strand structure at the active site, resulting in loss of two critical hydrogen-bond interactions involving residues His-227 and Arg-225, which are important for substrate binding and orientation for catalysis. These results provide a molecular basis for the phenotype associated with the R229W mutation, as well as providing a foundation for understanding the pathophysiological consequences of pyridoxine 5'-phosphate oxidase mutations.

  13. Direct and indirect effects of RNA interference against pyridoxal kinase and pyridoxine 5'-phosphate oxidase genes in Bombyx mori.

    Science.gov (United States)

    Huang, ShuoHao; Yao, LiLi; Zhang, JianYun; Huang, LongQuan

    2016-08-01

    Vitamin B6 comprises six interconvertible pyridine compounds (vitamers), among which pyridoxal 5'-phosphate is a coenzyme involved in a high diversity of biochemical reactions. Humans and animals obtain B6 vitamers from diet, and synthesize pyridoxal 5'-phosphate by pyridoxal kinase and pyridoxine 5'-phosphate oxidase. Currently, little is known on how pyridoxal 5'-phosphate biosynthesis is regulated, and pyridoxal 5'-phosphate is supplied to meet their requirement in terms of cofactor. Bombyx mori is a large silk-secreting insect, in which protein metabolism is most active, and the vitamin B6 demand is high. In this study, we successfully down-regulated the gene expression of pyridoxal kinase and pyridoxine 5'-phosphate oxidase by body cavity injection of synthesized double-stranded small interfering RNA to 5th instar larvae of Bombyx mori, and analyzed the gene transcription levels of pyridoxal 5'-phosphate dependent enzymes, phosphoserine aminotransferase and glutamic-oxaloacetic transaminase. Results show that the gene expression of pyridoxal kinase and pyridoxine 5'-phosphate oxidase has a greater impact on the gene transcription of enzymes using pyridoxal 5'-phosphate as a cofactor in Bombyx mori. Our study suggests that pyridoxal 5'-phosphate biosynthesis and dynamic balance may be regulated by genetic networks.

  14. LuxS-independent formation of AI-2 from ribulose-5-phosphate

    Directory of Open Access Journals (Sweden)

    Hardie Kim R

    2008-06-01

    Full Text Available Abstract Background In many bacteria, the signal molecule AI-2 is generated from its precursor S-ribosyl-L-homocysteine in a reaction catalysed by the enzyme LuxS. However, generation of AI-2-like activity has also been reported for organisms lacking the luxS gene and the existence of alternative pathways for AI-2 formation in Escherichia coli has recently been predicted by stochastic modelling. Here, we investigate the possibility that spontaneous conversion of ribulose-5-phosphate could be responsible for AI-2 generation in the absence of luxS. Results Buffered solutions of ribulose-5-phosphate, but not ribose-5-phosphate, were found to contain high levels of AI-2 activity following incubation at concentrations similar to those reported in vivo. To test whether this process contributes to AI-2 formation by bacterial cells in vivo, an improved Vibrio harveyi bioassay was used. In agreement with previous studies, culture supernatants of E. coli and Staphylococcus aureus luxS mutants were found not to contain detectable levels of AI-2 activity. However, low activities were detected in an E. coli pgi-eda-edd-luxS mutant, a strain which degrades glucose entirely via the oxidative pentose phosphate pathway, with ribulose-5-phosphate as an obligatory intermediate. Conclusion Our results suggest that LuxS-independent formation of AI-2, via spontaneous conversion of ribulose-5-phosphate, may indeed occur in vivo. It does not contribute to AI-2 formation in wildtype E. coli and S. aureus under the conditions tested, but may be responsible for the AI-2-like activities reported for other organisms lacking the luxS gene.

  15. Albino T-DNA tomato mutant reveals a key function of 1-deoxy-D-xylulose-5-phosphate synthase (DXS1) in plant development and survival

    Science.gov (United States)

    García-Alcázar, Manuel; Giménez, Estela; Pineda, Benito; Capel, Carmen; García-Sogo, Begoña; Sánchez, Sibilla; Yuste-Lisbona, Fernando J.; Angosto, Trinidad; Capel, Juan; Moreno, Vicente; Lozano, Rafael

    2017-01-01

    Photosynthetic activity is indispensable for plant growth and survival and it depends on the synthesis of plastidial isoprenoids as chlorophylls and carotenoids. In the non-mevalonate pathway (MEP), the 1-deoxy-D-xylulose-5-phosphate synthase 1 (DXS1) enzyme has been postulated to catalyze the rate-limiting step in the formation of plastidial isoprenoids. In tomato, the function of DXS1 has only been studied in fruits, and hence its functional relevance during plant development remains unknown. Here we report the characterization of the wls-2297 tomato mutant, whose severe deficiency in chlorophylls and carotenoids promotes an albino phenotype. Additionally, growth of mutant seedlings was arrested without developing vegetative organs, which resulted in premature lethality. Gene cloning and silencing experiments revealed that the phenotype of wls-2297 mutant was caused by 38.6 kb-deletion promoted by a single T-DNA insertion affecting the DXS1 gene. This was corroborated by in vivo and molecular complementation assays, which allowed the rescue of mutant phenotype. Further characterization of tomato plants overexpressing DXS1 and comparative expression analysis indicate that DXS1 may play other important roles besides to that proposed during fruit carotenoid biosynthesis. Taken together, these results demonstrate that DXS1 is essentially required for the development and survival of tomato plants. PMID:28350010

  16. Space weather forecasting with a Multimodel Ensemble Prediction System (MEPS)

    Science.gov (United States)

    Schunk, R. W.; Scherliess, L.; Eccles, V.; Gardner, L. C.; Sojka, J. J.; Zhu, L.; Pi, X.; Mannucci, A. J.; Butala, M.; Wilson, B. D.; Komjathy, A.; Wang, C.; Rosen, G.

    2016-07-01

    The goal of the Multimodel Ensemble Prediction System (MEPS) program is to improve space weather specification and forecasting with ensemble modeling. Space weather can have detrimental effects on a variety of civilian and military systems and operations, and many of the applications pertain to the ionosphere and upper atmosphere. Space weather can affect over-the-horizon radars, HF communications, surveying and navigation systems, surveillance, spacecraft charging, power grids, pipelines, and the Federal Aviation Administration (FAA's) Wide Area Augmentation System (WAAS). Because of its importance, numerous space weather forecasting approaches are being pursued, including those involving empirical, physics-based, and data assimilation models. Clearly, if there are sufficient data, the data assimilation modeling approach is expected to be the most reliable, but different data assimilation models can produce different results. Therefore, like the meteorology community, we created a Multimodel Ensemble Prediction System (MEPS) for the Ionosphere-Thermosphere-Electrodynamics (ITE) system that is based on different data assimilation models. The MEPS ensemble is composed of seven physics-based data assimilation models for the ionosphere, ionosphere-plasmasphere, thermosphere, high-latitude ionosphere-electrodynamics, and middle to low latitude ionosphere-electrodynamics. Hence, multiple data assimilation models can be used to describe each region. A selected storm event that was reconstructed with four different data assimilation models covering the middle and low latitude ionosphere is presented and discussed. In addition, the effect of different data types on the reconstructions is shown.

  17. Pyridoxal 5'-phosphate (PLP) deficiency might contribute to the onset of type I diabetes.

    Science.gov (United States)

    Rubí, B

    2012-01-01

    The incidence of type I diabetes is rising worldwide, particularly in young children. Type I diabetes is considered a multifactorial disease with genetic predisposition and environmental factors participating. Currently, despite years of research, there is no consensus regarding the factors that initiate the autoimmune response. Type I diabetes is preceded by autoimmunity to islet antigens, among them the protein glutamic acid decarboxylase, GAD-65. Pyridoxal 5'-phosphate (PLP) is formed from vitamin B6 by the action of pyridoxal kinase. Interaction of GAD65 with PLP is necessary for GAD65-mediated synthesis of the neurotransmitter γ-aminobutyric acid (GABA). PLP is also a required cofactor for dopamine synthesis by L-aromatic decarboxylase (L-AADC). Both GAD65 and L-AADC are expressed in pancreatic islets. Here it is proposed that lack of the vitamin B6 derivative pyridoxal 5'-phosphate might contribute to the appearance of pancreatic islet autoimmunity and type I diabetes onset.

  18. Structure of ribose 5-phosphate isomerase from the probiotic bacterium Lactobacillus salivarius UCC118.

    Science.gov (United States)

    Lobley, Carina M C; Aller, Pierre; Douangamath, Alice; Reddivari, Yamini; Bumann, Mario; Bird, Louise E; Nettleship, Joanne E; Brandao-Neto, Jose; Owens, Raymond J; O'Toole, Paul W; Walsh, Martin A

    2012-12-01

    The structure of ribose 5-phosphate isomerase from the probiotic bacterium Lactobacillus salivarius UCC188 has been determined at 1.72 Å resolution. The structure was solved by molecular replacement, which identified the functional homodimer in the asymmetric unit. Despite only showing 57% sequence identity to its closest homologue, the structure adopted the typical α and β D-ribose 5-phosphate isomerase fold. Comparison to other related structures revealed high homology in the active site, allowing a model of the substrate-bound protein to be proposed. The determination of the structure was expedited by the use of in situ crystallization-plate screening on beamline I04-1 at Diamond Light Source to identify well diffracting protein crystals prior to routine cryocrystallography.

  19. Effect of exogenous hormones on transcription levels of pyridoxal 5'-phosphate biosynthetic enzymes in the silkworm (Bombyx mori).

    Science.gov (United States)

    Huang, ShuoHao; Yang, HuanHuan; Yao, LiLi; Zhang, JianYun; Huang, LongQuan

    2016-01-01

    Vitamin B6 includes 6 pyridine derivatives, among which pyridoxal 5'-phosphate is a coenzyme for over 140 enzymes. Animals acquire their vitamin B6 from food. Through a salvage pathway, pyridoxal 5'-phosphate is synthesized from pyridoxal, pyridoxine or pyridoxamine, in a series of reactions catalyzed by pyridoxal kinase and pyridoxine 5'-phosphate oxidase. The regulation of pyridoxal 5'-phospahte biosynthesis and pyridoxal 5'-phospahte homeostasis are at the center of study for vitamin B6 nutrition. How pyridoxal 5'-phosphate biosynthesis is regulated by hormones has not been reported so far. Our previous studies have shown that pyridoxal 5'-phosphate level in silkworm larva displays cyclic developmental changes. In the current study, effects of exogenous juvenile hormone and molting hormone on the transcription level of genes coding for the enzymes involved in the biosynthesis of pyridoxal 5'-phospahte were examined. Results show that pyridoxal kinase and pyridoxine 5'-phosphate oxidase are regulated at the transcription level by development and are responsive to hormones. Molting hormone stimulates the expression of genes coding for pyridoxal kinase and pyridoxine 5'-phosphate oxidase, and juvenile hormone appears to work against molting hormone. Whether pyridoxal 5'-phosphate biosynthesis is regulated by hormones in general is an important issue for further studies.

  20. Structural characterization of a ribose-5-phosphate isomerase B from the pathogenic fungus Coccidioides immitis

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    Leibly David J

    2011-10-01

    Full Text Available Abstract Background Ribose-5-phosphate isomerase is an enzyme that catalyzes the interconversion of ribose-5-phosphate and ribulose-5-phosphate. This family of enzymes naturally occurs in two distinct classes, RpiA and RpiB, which play an important role in the pentose phosphate pathway and nucleotide and co-factor biogenesis. Results Although RpiB occurs predominantly in bacteria, here we report crystal structures of a putative RpiB from the pathogenic fungus Coccidioides immitis. A 1.9 Å resolution apo structure was solved by combined molecular replacement and single wavelength anomalous dispersion (SAD phasing using a crystal soaked briefly in a solution containing a high concentration of iodide ions. RpiB from C. immitis contains modest sequence and high structural homology to other known RpiB structures. A 1.8 Å resolution phosphate-bound structure demonstrates phosphate recognition and charge stabilization by a single positively charged residue whereas other members of this family use up to five positively charged residues to contact the phosphate of ribose-5-phosphate. A 1.7 Å resolution structure was obtained in which the catalytic base of C. immitis RpiB, Cys76, appears to form a weakly covalent bond with the central carbon of malonic acid with a bond distance of 2.2 Å. This interaction may mimic that formed by the suicide inhibitor iodoacetic acid with RpiB. Conclusion The C. immitis RpiB contains the same fold and similar features as other members of this class of enzymes such as a highly reactive active site cysteine residue, but utilizes a divergent phosphate recognition strategy and may recognize a different substrate altogether.

  1. It takes two to tango: defining an essential second active site in pyridoxal 5'-phosphate synthase.

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    Cyril Moccand

    Full Text Available The prevalent de novo biosynthetic pathway of vitamin B6 involves only two enzymes (Pdx1 and Pdx2 that form an ornate multisubunit complex functioning as a glutamine amidotransferase. The synthase subunit, Pdx1, utilizes ribose 5-phosphate and glyceraldehyde 3-phosphate, as well as ammonia derived from the glutaminase activity of Pdx2 to directly form the cofactor vitamer, pyridoxal 5'-phosphate. Given the fact that a single enzyme performs the majority of the chemistry behind this reaction, a complicated mechanism is anticipated. Recently, the individual steps along the reaction co-ordinate are beginning to be unraveled. In particular, the binding of the pentose substrate and the first steps of the reaction have been elucidated but it is not known if the latter part of the chemistry, involving the triose sugar, takes place in the same or a disparate site. Here, we demonstrate through the use of enzyme assays, enzyme kinetics, and mutagenesis studies that indeed a second site is involved in binding the triose sugar and moreover, is the location of the final vitamin product, pyridoxal 5'-phosphate. Furthermore, we show that product release is triggered by the presence of a PLP-dependent enzyme. Finally, we provide evidence that a single arginine residue of the C terminus of Pdx1 is responsible for coordinating co-operativity in this elaborate protein machinery.

  2. Novel Method of Synthesis of 5''-Phosphate 2'-O-ribosyl-ribonucleosides and Their 3'-Phosphoramidites

    Directory of Open Access Journals (Sweden)

    Marcin K. Chmielewski

    2013-11-01

    Full Text Available Synthesis of 5''-phosphate 2'-O-ribosylribonucleosides [Nr(p] of four common ribonucleosides, and 3'-phosphoramidites of 5''-phosphate 2'-O-ribosyladenosine and 2'-O-ribosylguanosine using the H-phosphonate chemistry is described. An additional ring protected by benzoyl groups was incorporated into the main ribosyl ring in the reaction with 1-O-acetyl-2,3,5-tri-O-benzoyl-β-d-ribofuranose in the presence of SnCl4. The obtained 2'-O-ribosylribonucleosides (Nr were applied in the subsequent transformations with selective deprotection. Ethanolamine was applied as a very convenient reagent for selective removal of benzoyl groups. Additionally, the tetraisopropyldisiloxane-1,3-diyl (TIPDSi group was found to be stable under these deprotection conditions. Thus, the selectively deprotected 5''-hydroxyl group of Nr was transformed into an H-phosphonate monoester which was found to be stable under the following conditions: the removal of the TIPDSi group with triethylammonium fluoride and the dimethoxytritylation of the 5''-hydroxyl function. The 5''-H-phosphonate of Nr precursors was easily transformed to the corresponding dicyanoethyl 5''-O-phosphotriesters before phosphitylation, which gave 3'-phosphoramidite units of Nr(p in high yield. The derived phosphoramidite units were used in an automated oligonucleotide synthesizer to produce dimer Ar(pT via the phosphoramidite approach. The obtained products were fully deprotected under standard deprotection conditions giving dimers with a 5''-phosphate monoester function. Application of an alkaline phosphatase to prove the presence of an additional phosphate group was described.

  3. Acetate selective fluorescent turn-on sensors derived using vitamin B6 cofactor pyridoxal-5-phosphate

    Science.gov (United States)

    Sharma, Darshna; Kuba, Aman; Thomas, Rini; Ashok Kumar, S. K.; Kuwar, Anil; Choi, Heung-Jin; Sahoo, Suban K.

    2016-03-01

    Two new Schiff base receptors have been synthesized by condensation of pyridoxal-5-phosphate with 2-aminophenol (L1) or aniline (L2). In DMSO, the receptors showed both chromogenic and 'turn-on' fluorescence responses selectively in the presence of AcO- and F-. However, in mixed DMSO-H2O medium, the receptors showed AcO- selective 'turn-on' fluorescence without any interference from other tested anions including F-. The detection limit for AcO- was found to be 7.37 μM and 22.9 μM using the receptors L1 and L2, respectively.

  4. Pcal_1127, a highly stable and efficient ribose-5-phosphate pyrophosphokinase from Pyrobaculum calidifontis.

    Science.gov (United States)

    Bibi, Tahira; Perveen, Sumera; Aziz, Iram; Bashir, Qamar; Rashid, Naeem; Imanaka, Tadayuki; Akhtar, Muhammad

    2016-11-01

    Analysis of the genome sequence of Pyrobaculum calidifontis revealed the presence of an open reading frame Pcal_1127 annotated as ribose-5-phosphate pyrophosphokinase. To examine the properties of Pcal_1127 the coding gene was cloned, expressed in Escherichia coli, and the purified gene product was characterized. Pcal_1127 exhibited higher activity when ATP was replaced by dATP as pyrophosphate donor. Phosphate and EDTA activated the enzyme activity and equivalent amount of activity was detected with ATP and dATP in their presence. Recombinant Pcal_1127 could utilize all the four nucleotides as pyrophosphate donors with a marked preference for ATP. Optimum temperature and pH for the enzyme activity were 55 °C and 10.5, respectively. A unique feature of Pcal_1127 was its stability against temperature as well as denaturants. Pcal_1127 exhibited more than 95 % residual activity after heating for 4 h at 90 °C and a half-life of 15 min in the boiling water. The enzyme activity was not affected by the presence of 8 M urea or 4 M guanidinium chloride. Pcal_1127 was a highly efficient enzyme with a catalytic efficiency of 5183 mM(-1) s(-1). These features make Pcal_1127, a novel and unique ribose-5-phosphate pyrophosphokinase.

  5. Electroencephalographic and seizure manifestations of pyridoxal 5'-phosphate-dependent epilepsy.

    Science.gov (United States)

    Veerapandiyan, Aravindhan; Winchester, Sara A; Gallentine, William B; Smith, Edward C; Kansagra, Sujay; Hyland, Keith; Mikati, Mohamad A

    2011-03-01

    We describe the electroencephalographic and clinical seizure manifestations of pyridoxal 5'-phosphate-dependent epilepsy (PLP-DE) in two patients [diagnosis confirmed by low cerebrospinal fluid (CSF) PLP, complete resolution of previously intractable seizures with PLP supplementation, negative pyridoxine-dependent epilepsy CSF biomarkers, and/or positive disease causing pyridox(am)ine 5'-phosphate oxidase gene mutation] along with a comprehensive review of the literature. One patient presented with neonatal tonic status epilepticus with subsequent generalized tonic-clonic seizures, and the second, with refractory complex partial seizures starting at 2 years of age. The pretreatment EEG revealed, interictally, burst suppression, multifocal independent sharp waves, and electrical status epilepticus in sleep. Ictally and interictally, it revealed runs of unilateral spike/slow waves. Previously reported features include burst suppression, myoclonus, tonic seizures, clonic seizures, and spasms. In the appropriate clinical scenario, the aforementioned features should raise the possibility of PLP-DE and appropriate treatment should be initiated. The first late-onset case (at 2 years) of PLP-DE is reported.

  6. Synthesis of acylamino acid esters of nucleoside 5'-phosphates and their investigation with PMR and CD spectra.

    Science.gov (United States)

    Azhayev, A V; Popovkina, S V; Tarussova, N B; Kirpichnikov, M P; Florentiev, V L; Krayevsky, A A; Kukhanova, M K; Gottikh, B P

    1977-01-01

    The acylamino acid esters of nucleoside 5'-phosphates are synthesized via condensation of N-(N'-acylaminoacyl) imidazoles with nucleoside 5'-phosphates. The PMR and CD spectra of the esters obtained are studied. The 3'-isomers of the substances under study are observed to have a shift in the conformational N in equilibrium S equilibrium of the carbohydrate moiety in favour of the S-form as compared to the initial nucleosides and their 2'-acyl esters. PMID:909771

  7. Functional and evolutionary analysis of DXL1, a non-essential gene encoding a 1-deoxy-D-xylulose 5-phosphate synthase like protein in Arabidopsis thaliana.

    Science.gov (United States)

    Carretero-Paulet, Lorenzo; Cairó, Albert; Talavera, David; Saura, Andreu; Imperial, Santiago; Rodríguez-Concepción, Manuel; Campos, Narciso; Boronat, Albert

    2013-07-15

    The synthesis of 1-deoxy-D-xylulose 5-phosphate (DXP), catalyzed by the enzyme DXP synthase (DXS), represents a key regulatory step of the 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway for isoprenoid biosynthesis. In plants DXS is encoded by small multigene families that can be classified into, at least, three specialized subfamilies. Arabidopsis thaliana contains three genes encoding proteins with similarity to DXS, including the well-known DXS1/CLA1 gene, which clusters within subfamily I. The remaining proteins, initially named DXS2 and DXS3, have not yet been characterized. Here we report the expression and functional analysis of A. thaliana DXS2. Unexpectedly, the expression of DXS2 failed to rescue Escherichia coli and A. thaliana mutants defective in DXS activity. Coherently, we found that DXS activity was negligible in vitro, being renamed as DXL1 following recent nomenclature recommendation. DXL1 is targeted to plastids as DXS1, but shows a distinct expression pattern. The phenotypic analysis of a DXL1 defective mutant revealed that the function of the encoded protein is not essential for growth and development. Evolutionary analyses indicated that DXL1 emerged from DXS1 through a recent duplication apparently specific of the Brassicaceae lineage. Divergent selective constraints would have affected a significant fraction of sites after diversification of the paralogues. Furthermore, amino acids subjected to divergent selection and likely critical for functional divergence through the acquisition of a novel, although not yet known, biochemical function, were identified. Our results provide with the first evidences of functional specialization at both the regulatory and biochemical level within the plant DXS family.

  8. Prerequisite for highly efficient isoprenoid production by cyanobacteria discovered through the over-expression of 1-deoxy-d-xylulose 5-phosphate synthase and carbon allocation analysis.

    Science.gov (United States)

    Kudoh, Kai; Kawano, Yusuke; Hotta, Shingo; Sekine, Midori; Watanabe, Takafumi; Ihara, Masaki

    2014-07-01

    Cyanobacteria have recently been receiving considerable attention owing to their potential as photosynthetic producers of biofuels and biomaterials. Here, we focused on the production of isoprenoids by cyanobacteria, and aimed to provide insight into metabolic engineering design. To this end, we examined the over-expression of a key enzyme in 2-C-methyl-d-erythritol 4-phosphate (MEP) pathway, 1-deoxy-d-xylulose 5-phosphate synthase (DXS) in the cyanobacterium Synechocystis sp. PCC6803. In the DXS-over-expression strain (Dxs_ox), the mRNA and protein levels of DXS were 4-times and 1.5-times the levels in the wild-type (WT) strain, respectively. The carotenoid content of the Dxs_ox strain (8.4 mg/g dry cell weight [DCW]) was also up to 1.5-times higher than that in the WT strain (5.6 mg/g DCW), whereas the glycogen content dramatically decreased to an undetectable level. These observations suggested that the carotenoid content in the Dxs_ox strain was increased by consuming glycogen, which is a C-storage compound in cyanobacteria. We also quantified the total sugar (145 and 104 mg/g DCW), total fatty acids (31 and 24 mg/g DCW) and total protein (200 and 240 mg/g DCW) content in the WT and Dxs_ox strains, respectively, which were much higher than the carotenoid content. In particular, approximately 54% of the proteins were phycobiliproteins. This study demonstrated the major destinations of carbon flux in cyanobacteria, and provided important insights into metabolic engineering. Target yield can be improved through optimization of gene expression, the DXS protein stabilization, cell propagation depression and restriction of storage compound synthesis.

  9. Identification of GutQ from Escherichia coli as a D-arabinose 5-phosphate isomerase.

    Science.gov (United States)

    Meredith, Timothy C; Woodard, Ronald W

    2005-10-01

    The glucitol operon (gutAEBDMRQ) of Escherichia coli encodes a phosphoenolpyruvate:sugar phosphotransferase system that metabolizes the hexitol D-glucitol (sorbitol). The functions for all but the last gene, gutQ, have been previously assigned. The high sequence similarity between GutQ and KdsD, a D-arabinose 5-phosphate isomerase (API) from the 3-deoxy-D-manno-octulosonate (KDO)-lipopolysaccharide (LPS) biosynthetic pathway, suggested a putative activity, but its role within the context of the gut operon remained unclear. Accordingly, the enzyme was cloned, overexpressed, and characterized. Recombinant GutQ was shown to indeed be a second copy of API from the E. coli K-12 genome with biochemical properties similar to those of KdsD, catalyzing the reversible aldol-ketol isomerization between D-ribulose 5-phosphate (Ru5P) and D-arabinose 5-phosphate (A5P). Genomic disruptions of each API gene were constructed in E. coli K-12. TCM11[(deltakdsD)] was capable of sustaining essential LPS synthesis at wild-type levels, indicating that GutQ functions as an API inside the cell. The gut operon remained inducible in TCM7[(deltagutQ)], suggesting that GutQ is not directly involved in d-glucitol catabolism. The conditional mutant TCM15[(deltagutQdeltakdsD)] was dependent on exogenous A5P both for LPS synthesis/growth and for upregulation of the gut operon. The phenotype was suppressed by complementation in trans with a plasmid encoding a functional copy of GutQ or by increasing the amount of A5P in the medium. As there is no obvious obligatory role for GutQ in the metabolism of d-glucitol and there is no readily apparent link between D-glucitol metabolism and LPS biosynthesis, it is suggested that A5P is not only a building block for KDO biosynthesis but also may be a regulatory molecule involved in expression of the gut operon.

  10. A nutritional conditional lethal mutant due to pyridoxine 5'-phosphate oxidase deficiency in Drosophila melanogaster.

    Science.gov (United States)

    Chi, Wanhao; Zhang, Li; Du, Wei; Zhuang, Xiaoxi

    2014-04-16

    The concept of auxotrophic complementation has been proposed as an approach to identify genes in essential metabolic pathways in Drosophila melanogaster. However, it has achieved limited success to date, possibly due to the low probability of finding mutations fit with the chemically defined profile. Instead of using the chemically defined culture media lacking specific nutrients, we used bare minimum culture medium, i.e., 4% sucrose, for adult Drosophila. We identified a nutritional conditional lethal mutant and localized a c.95C > A mutation in the Drosophila pyridoxine 5'-phosphate oxidase gene [dPNPO or sugarlethal (sgll)] using meiotic recombination mapping, deficiency mapping, and whole genome sequencing. PNPO converts dietary vitamin B6 such as pyridoxine to its active form pyridoxal 5'-phosphate (PLP). The missense mutation (sgll(95)) results in the substitution of alanine to aspartate (p.Ala32Asp). The sgll(95) flies survive well on complete medium but all die within 6 d on 4% sucrose only diet, which can be rescued by pyridoxine or PLP supplement, suggesting that the mutation does not cause the complete loss of PNPO activity. The sgll knockdown further confirms its function as the Drosophila PNPO. Because better tools for positional cloning and cheaper whole genome sequencing have made the identification of point mutations much easier than before, alleviating the necessity to pinpoint specific metabolic pathways before gene identification, we propose that nutritional conditional screens based on bare minimum growth media like ours represent promising approaches for discovering important genes and mutations in metabolic pathways, thereby accelerating the establishment of in vivo models that recapitulate human metabolic diseases.

  11. 76 FR 43264 - Proposed Information Collection; Comment Request; NIST MEP Client Impact Survey

    Science.gov (United States)

    2011-07-20

    ..., profitability, and enhance their economic competitiveness. The information collected will provide the MEP with..., 292, and H.R. 1274--section 2). The information collected will include MEP customer inputs regarding their sales, costs, investments, ] employment, and exports. Customers will only be surveyed...

  12. 77 FR 12041 - Applications for New Awards; Migrant Education Program (MEP) Consortium Incentive Grants Program

    Science.gov (United States)

    2012-02-28

    ... Applications for New Awards; Migrant Education Program (MEP) Consortium Incentive Grants Program AGENCY: Office...: Migrant Education Program (MEP) Consortium Incentive Grants Program; Notice inviting applications for new... appropriate entities to improve the delivery of services to migrant children whose education is...

  13. MESA/MEP at American River College: Year One Evaluation Report.

    Science.gov (United States)

    Lee, Beth S.; And Others

    In 1989, the Mathematics, Engineering, and Science Achievement (MESA)/Minority Engineering Program (MEP) was initiated at American River College. The MESA/MEP program recruits Black, Hispanic, and Native American students and provides assistance, encouragement, and enrichment programs to help them succeed in the fields of mathematics, engineering,…

  14. 34 CFR 200.89 - MEP allocations; Re-interviewing; Eligibility documentation; and Quality control.

    Science.gov (United States)

    2010-07-01

    ... THE ACADEMIC ACHIEVEMENT OF THE DISADVANTAGED Migrant Education Program § 200.89 MEP allocations; Re...-interviewing; (iv) Determine and document in writing whether the child eligibility determination and the... determining and documenting child eligibility under the MEP. (2) Supervision and annual review and evaluation...

  15. Clinical Value of the Assessment of Changes in MEP Duration with Voluntary Contraction.

    Science.gov (United States)

    Brum, Marisa; Cabib, Christopher; Valls-Solé, Josep

    2015-01-01

    Transcranial magnetic stimulation (TMS) gives rise to muscle responses, known as motor evoked potentials (MEP), through activation of the motor pathways. Voluntary contraction causes facilitation of MEPs, which consists of shortening MEP latency, increasing MEP amplitude and widening MEP duration. While an increase in excitability of alpha motorneurons and the corticospinal tract can easily explain latency shortening and amplitude increase, other mechanisms have to be accounted for to explain the increase in duration. We measured the increase in duration of the MEP during contraction with respect to rest in a group of healthy volunteers and retrospectively assessed this parameter in patients who were examined in a standardized fashion during the past 5 years. We included 25 healthy subjects, 21 patients with multiple sclerosis, 33 patients with acute stroke, 5 patients with hereditary spastic paraparesis, and 5 patients with signs suggesting psychogenic paresis. We found already significant differences among groups in the MEP duration at rest, patients with MS had a significantly longer duration, and patients with stroke had significantly shorter duration, than the other two groups. The increase in MEP duration during voluntary contraction was different in patients and in healthy subjects. It was significantly shorter in MS and significantly longer in stroke patients. It was absent in the five patients with suspected psychogenic weakness. In patients with HSP, an abnormally increase in duration occurred only in leg muscles. Our results suggest that the increase in duration of the MEP during contraction may reveal the contribution of propriospinal interneurons to the activation of alpha motorneurons. This mechanism may be altered in some diseases and, therefore, the assessment proposed in this work may have clinical applicability for the differential diagnosis of weakness.

  16. Clinical value of the assessment of changes in MEP duration with voluntary contraction

    Directory of Open Access Journals (Sweden)

    Josep eValls-Sole

    2016-01-01

    Full Text Available Transcranial magnetic stimulation (TMS gives rise to muscle responses, known as motor evoked potentials (MEP, through activation of the motor pathways. Voluntary contraction causes facilitation of MEPs, which consists of shortening MEP latency, increasing MEP amplitude and widening MEP duration. While an increase in excitability of alpha motorneurons and the corticospinal tract can easily explain latency shortening and amplitude increase, other mechanisms have to be accounted for to explain the increase in duration. We measured the extent of the increase in duration that adds at the end of the MEP during contraction with respect to rest in a group of healthy volunteers and retrospectively assessed this parameter in patients who were examined in a standardized fashion during the past 5 years. We included 25 healthy subjects, 21 patients with multiple sclerosis, 33 patients with acute stroke, 5 patients with hereditary spastic paraparesis and 5 patients with signs suggesting psychogenic paresis. We found already significant differences among groups in the MEP duration at rest, patients with MS had a significantly longer duration, and patients with stroke had significantly shorter duration, than the other two groups. The increase in MEP duration during voluntary contraction was different in patients and in healthy subjects. It was significantly shorter in MS and significantly longer in stroke patients. It was absent in the 5 patients with suspected psychogenic weakness. In patients with HSP, an abnormally increase in duration occurred only in leg muscles. Our results suggest that the increase in duration of the MEP during contraction may reveal the contribution of propriospinal interneurons to the activation of alpha motorneurons. This mechanism may be altered in some diseases and, therefore, the assessment proposed in this work may have clinical applicability for the differential diagnosis of weakness.

  17. Engineering a functional 1-deoxy-D-xylulose 5-phosphate (DXP) pathway in Saccharomyces cerevisiae

    Energy Technology Data Exchange (ETDEWEB)

    Kirby, James [Univ. of California, Berkeley, CA (United States). California Institute of Quantitative Biosciences (QB3); Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Dietzel, Kevin L. [Amyris, inc., Emeryville, CA (United States); Wichmann, Gale [Amyris, inc., Emeryville, CA (United States); Chan, Rossana [Univ. of California, Berkeley, CA (United States). California Institute of Quantitative Biosciences (QB3); Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Antipov, Eugene [Amyris, inc., Emeryville, CA (United States); Moss, Nathan [Amyris, inc., Emeryville, CA (United States); Baidoo, Edward E. K. [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Jackson, Peter [Amyris, inc., Emeryville, CA (United States); Gaucher, Sara P. [Amyris, inc., Emeryville, CA (United States); Gottlieb, Shayin [Amyris, inc., Emeryville, CA (United States); LaBarge, Jeremy [Amyris, inc., Emeryville, CA (United States); Mahatdejkul, Tina [Amyris, inc., Emeryville, CA (United States); Hawkins, Kristy M. [Amyris, inc., Emeryville, CA (United States); Muley, Sheela [Amyris, inc., Emeryville, CA (United States); Newman, Jack D. [Amyris, inc., Emeryville, CA (United States); Liu, Pinghua [Boston Univ., MA (United States). Dept. of Chemistry; Keasling, Jay D. [Univ. of California, Berkeley, CA (United States). California Institute of Quantitative Biosciences (QB3); Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Univ. of California, Berkeley, CA (United States). Depts. of Chemical & Biomolecular Engineering and Bioengineering; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Biological Systems & Engineering Div.; Technical Univ. of Denmark, Hoesholm (Denmark). Novo Nodisk Foundation Center for Biosustainability; Zhao, Lishan [Amyris, inc., Emeryville, CA (United States)

    2016-10-27

    Isoprenoids are made by all free-living organisms and range from essential metabolites like sterols and quinones to more complex compounds like pinene and rubber. They are used in many commercial applications and much work has gone into engineering microbial hosts for their production. Isoprenoids are produced either from acetyl-CoA via the mevalonate pathway or from pyruvate and glyceraldehyde 3-phosphate via the 1-deoxy-D-xylulose 5-phosphate (DXP) pathway. Saccharomyces cerevisiae exclusively utilizes the mevalonate pathway to synthesize native isoprenoids and in fact the alternative DXP pathway has never been found or successfully reconstructed in the eukaryotic cytosol. There are, however, several advantages to isoprenoid synthesis via the DXP pathway, such as a higher theoretical yield, and it has long been a goal to transplant the pathway into yeast. In this work, we investigate and address barriers to DXP pathway functionality in S. cerevisiae using a combination of synthetic biology, biochemistry and metabolomics. We report, for the first time, functional expression of the DXP pathway in S. cerevisiae. Under low aeration conditions, an engineered strain relying solely on the DXP pathway for isoprenoid biosynthesis achieved an endpoint biomass 80% of that of the same strain using the mevalonate pathway.

  18. Potential role of pyridoxal-5'-phosphate phosphatase/chronopin in epilepsy.

    Science.gov (United States)

    Kim, Ji-Eun; Kim, Dae-Won; Kwak, Sung-Eun; Kwon, Oh-Shin; Choi, Soo-Young; Kang, Tae-Cheon

    2008-05-01

    Changes in actin dynamics and pyridoxal-5'-phosphate (PLP) metabolisms are closely related to the pathophysiological profiles of the epileptic hippocampus. Recently, it has been reported that PLP phosphatase/chronophin (PLPP/CIN) directly dephosphorylates actin-depolymerizing factor (ADF)/cofilin as well as PLP. In the present study, therefore, we have investigated whether PLPP/CIN is linked to the dynamics of actin filament assembly and the excitability in the rat hippocampus. In control animals, pyridoxine chloride (PNP) treatment increased PLPP/CIN immunoreactivity only in astrocytes, which did not affect electrophysiological properties. Following status epilepticus, the PLPP/CIN protein level increased in granule cells and reactive astrocytes. These changes in PLPP/CIN protein level showed an inverse correlation with phospho-ADF (pADF)/cofilin levels and F-actin content. These changes were also accompanied by alterations in the excitability ratio and paired-pulse inhibition. Transduction of PLPP/CIN by Tat-PLPP/CIN showed similar effects on pADF/cofilin levels, F-actin content and excitability ratio in normal animals. These findings suggest that PLPP/CIN-mediated actin dynamics may play an important role in the changes of morphological properties and excitability of the epileptic hippocampus.

  19. Pyridoxal 5'-phosphate is a slow tight binding inhibitor of E. coli pyridoxal kinase.

    Directory of Open Access Journals (Sweden)

    Mohini S Ghatge

    Full Text Available Pyridoxal 5'-phosphate (PLP is a cofactor for dozens of B(6 requiring enzymes. PLP reacts with apo-B(6 enzymes by forming an aldimine linkage with the ε-amino group of an active site lysine residue, thus yielding the catalytically active holo-B(6 enzyme. During protein turnover, the PLP is salvaged by first converting it to pyridoxal by a phosphatase and then back to PLP by pyridoxal kinase. Nonetheless, PLP poses a potential toxicity problem for the cell since its reactive 4'-aldehyde moiety forms covalent adducts with other compounds and non-B(6 proteins containing thiol or amino groups. The regulation of PLP homeostasis in the cell is thus an important, yet unresolved issue. In this report, using site-directed mutagenesis, kinetic, spectroscopic and chromatographic studies we show that pyridoxal kinase from E. coli forms a complex with the product PLP to form an inactive enzyme complex. Evidence is presented that, in the inhibited complex, PLP has formed an aldimine bond with an active site lysine residue during catalytic turnover. The rate of dissociation of PLP from the complex is very slow, being only partially released after a 2-hour incubation with PLP phosphatase. Interestingly, the inactive pyridoxal kinase•PLP complex can be partially reactivated by transferring the tightly bound PLP to an apo-B(6 enzyme. These results open new perspectives on the mechanism of regulation and role of pyridoxal kinase in the Escherichia coli cell.

  20. Engineering a functional 1-deoxy-D-xylulose 5-phosphate (DXP) pathway in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Kirby, James; Dietzel, Kevin L.; Wichmann, Gale;

    2016-01-01

    Isoprenoids are used in many commercial applications and much work has gone into engineering microbial hosts for their production. Isoprenoids are produced either from acetyl-CoA via the mevalonate pathway or from pyruvate and glyceraldehyde 3-phosphate via the 1-deoxy-D-xylulose 5-phosphate (DXP...

  1. 78 FR 21109 - Manufacturing Extension Partnership (MEP) Center for Nebraska; Availability of Funds

    Science.gov (United States)

    2013-04-09

    ... National Institute of Standards and Technology Manufacturing Extension Partnership (MEP) Center for... applicants for funding projects that provide manufacturing extension services to primarily small- and medium... obtained by contacting Diane Henderson, National Institute of Standards and Technology,...

  2. 77 FR 12563 - Manufacturing Extension Partnership (MEP) Centers for South Dakota and Kentucky; Availability of...

    Science.gov (United States)

    2012-03-01

    ... National Institute of Standards and Technology Manufacturing Extension Partnership (MEP) Centers for South... eligible proposers for funding projects to provide manufacturing extension services to primarily small- and... Diane Henderson, National Institute of Standards and Technology, Manufacturing Extension...

  3. 75 FR 33769 - Manufacturing Extension Partnership (MEP) Availability of Funds for Projects To Develop and...

    Science.gov (United States)

    2010-06-15

    ... with the NIST MEP Program's five Strategic Growth Areas (Supply Chain, Sustainability, Technology... focus are: Supply Chain, Sustainability, Technology Acceleration, Workforce and Continuous Improvement... Growth Areas (Supply Chain, Sustainability, Technology Acceleration, Workforce and Continuous Improvement...

  4. The Percentage of Amplitude Decrease Warning Criteria for Transcranial MEP Monitoring.

    Science.gov (United States)

    Journée, Henricus L; Berends, Hanneke I; Kruyt, Moyo C

    2017-01-01

    Muscle motor evoked potentials (MEPs) from transcranial electrical stimulation (TES) became a standard technique for monitoring the motor functions of the brain and spinal cord at risk during spinal and brain surgery. However, a wide range of criteria based on the percentage of amplitude decrease is used in practice. A survey of the current literature on clinical outcome parameters reveals a variety of percentages in a range of 30% to 100% (50% to 100% spinal procedures) with no consensus. The interpretation of muscle MEPs is hampered by their sensitivity to many interfering factors. Trial-to-trial MEP variations may partly be reduced by controllable parameters of which TES parameters are in the hands of the neuromonitorist. We propose an operational model based on basic neurophysiologic knowledge to interpret the characteristics of MEP-TES voltage curves and predict the influences of the location on the sigmoid voltage curve on spontaneous MEP-variations and influences of factors affecting the voltage curve. The model predicts a correlation between the slope, expressed by a gain, and variations of muscle MEP amplitudes. This complies with two case examples. The limited specificity/sensitivity of warning criteria based on the percentage of amplitude reduction can possibly be improved by developing standards for set-up procedures of TES paradigms. These procedures include strategies for desensitizing MEPs for variations of controllable parameters. The TES voltage or current is a feasible controlling parameter and should be related to the motor threshold and the onset of the supramaximal level being landmarks of MEP-voltage functions. These parameters may offer a valuable addition to multicenter outcome studies.

  5. Prevention of the immune agglutination of methyl acetimidate-reacted sickle erythrocytes by prior reaction with pyridoxal 5'-phosphate.

    Science.gov (United States)

    Chao, T L; Berenfeld, M R

    1981-06-10

    The appearance of an immune response in some sickle cell anemia patients to reinfused autologous erythrocytes which had been treated with methyl acetimidate (Gabuzda, T. G., Chao, T. L., Berenfeld, M. R., and Gelbart, T. (1980) Blood 56, 1041--1047) was a serious impediment to the clinical application of this reagent as an extracorporeal antisickling agent. The immune reaction was doubtlessly due to acetamidination of membrane protein amino groups. Protection of these amino groups with a reversible reagent prior to treatment of the cells with methyl acetimidate should prevent the antigenic reaction. This result was realized by preequilibration of erythrocytes with pyridoxal 5'-phosphate prior to addition of methyl acetimidate. Subsequent washing of the cells to remove excess reagents and to hydrolyze the pyridoxal 5'-phosphate/membrane protein Schiff base adduct regenerates native protein amino groups of the erythrocyte membrane.

  6. Pyridox(am)ine-5-Phosphate Oxidase Deficiency Treatable Cause of Neonatal Epileptic Encephalopathy With Burst Suppression: Case Report and Review of the Literature.

    Science.gov (United States)

    Guerin, Andrea; Aziz, Aly S; Mutch, Carly; Lewis, Jillian; Go, Cristina Y; Mercimek-Mahmutoglu, Saadet

    2015-08-01

    Pyridox(am)ine-5-phosphate oxidase deficiency is an autosomal recessive disorder of pyridoxine metabolism. Intractable neonatal epileptic encephalopathy is the classical presentation. Pyridoxal-5-phosphate or pyridoxine supplementation improves symptoms. We report a patient with myoclonic and tonic seizures at the age of 1 hour. Pyridoxal-5-phosphate was started on the first day of life and seizures stopped at the age of 3 days, but encephalopathy persisted for 4 weeks. She had normal neurodevelopmental outcome at the age of 12 months on pyridoxal-5-phosphate monotherapy. She had novel homozygous pathogenic frameshift mutation (c.448_451del;p.Pro150Argfs*27) in the PNPO gene. Long-lasting encephalopathy despite well-controlled clinical seizures does neither confirm nor exclude pyridox(am)ine-5-phosphate oxidase deficiency. Normal neurodevelopmental outcome of our patient emphasizes the importance of pyridoxal-5-phosphate treatment. Pyridox(am)ine-5-phosphate oxidase deficiency should be included in the differential diagnosis of Ohtahara syndrome and neonatal myoclonic encephalopathy as a treatable underlying cause. In addition, we reviewed the literature for pyridox(am)ine-5-phosphate oxidase deficiency and summarized herein all confirmed cases.

  7. Phosphoinositide 5-Phosphate and Phosphoinositide 4-Phosphate Trigger Distinct Specific Responses of Arabidopsis Genes: Genome-Wide Expression Analyses

    OpenAIRE

    2006-01-01

    Phosphoinositide phosphates, PtdInsP, are important components of the cell lipid pool that can function as messengers in diverse cellular processes. Lack of information on downstream targets, however, has impeded our understanding of the potential of lipid-signaling to influence gene activity. Our goals here were to identify genes that altered expression in the presence of two isomeric monophosphate lipid messengers (Phosphoinositide 5-Phosphate, PtdIns(5)P, and Phosphoinositide 4-Phosphate, ...

  8. Experimental Evidence for a Revision in the Annotation of Putative Pyridoxamine 5'-Phosphate Oxidases P(N/MP from Fungi.

    Directory of Open Access Journals (Sweden)

    Tatiana Domitrovic

    Full Text Available Pyridoxinamine 5'-phosphate oxidases (P(N/MP oxidases that bind flavin mononucleotide (FMN and oxidize pyridoxine 5'-phosphate or pyridoxamine 5'-phosphate to form pyridoxal 5'-phosphate (PLP are an important class of enzymes that play a central role in cell metabolism. Failure to generate an adequate supply of PLP is very detrimental to most organisms and is often clinically manifested as a neurological disorder in mammals. In this study, we analyzed the function of YLR456W and YPR172W, two homologous genes of unknown function from S. cerevisiae that have been annotated as putative P(N/MP oxidases based on sequence homology. Different experimental approaches indicated that neither protein catalyzes PLP formation nor binds FMN. On the other hand, our analysis confirmed the enzymatic activity of Pdx3, the S. cerevisiae protein previously implicated in PLP biosynthesis by genetic and structural characterization. After a careful sequence analysis comparing the putative and confirmed P(N/MP oxidases, we found that the protein domain (PF01243 that led to the YLR456W and YPR172W annotation is a poor indicator of P(N/MP oxidase activity. We suggest that a combination of two Pfam domains (PF01243 and PF10590 present in Pdx3 and other confirmed P(N/MP oxidases would be a stronger predictor of this molecular function. This work exemplifies the importance of experimental validation to rectify genome annotation and proposes a revision in the annotation of at least 400 sequences from a wide variety of fungal species that are homologous to YLR456W and are currently misrepresented as putative P(N/MP oxidases.

  9. A unique arabinose 5-phosphate isomerase found within a genomic island associated with the uropathogenicity of Escherichia coli CFT073.

    Science.gov (United States)

    Mosberg, Joshua A; Yep, Alejandra; Meredith, Timothy C; Smith, Sara; Wang, Pan-Fen; Holler, Tod P; Mobley, Harry L T; Woodard, Ronald W

    2011-06-01

    Previous studies showed that deletion of genes c3405 to c3410 from PAI-metV, a genomic island from Escherichia coli CFT073, results in a strain that fails to compete with wild-type CFT073 after a transurethral cochallenge in mice and is deficient in the ability to independently colonize the mouse kidney. Our analysis of c3405 to c3410 suggests that these genes constitute an operon with a role in the internalization and utilization of an unknown carbohydrate. This operon is not found in E. coli K-12 but is present in a small number of pathogenic E. coli and Shigella boydii strains. One of the genes, c3406, encodes a protein with significant homology to the sugar isomerase domain of arabinose 5-phosphate isomerases but lacking the tandem cystathionine beta-synthase domains found in the other arabinose 5-phosphate isomerases of E. coli. We prepared recombinant c3406 protein, found it to possess arabinose 5-phosphate isomerase activity, and characterized this activity in detail. We also constructed a c3406 deletion mutant of E. coli CFT073 and demonstrated that this deletion mutant was still able to compete with wild-type CFT073 in a transurethral cochallenge in mice and could colonize the mouse kidney. These results demonstrate that the presence of c3406 is not essential for a pathogenic phenotype.

  10. Why Do MEPs Defect? An Analysis of Party Group Cohesion in the 5 th European Parliament

    Directory of Open Access Journals (Sweden)

    Thorsten Faas

    2002-03-01

    Full Text Available This study analyses party group cohesion and patterns of defections of national party delegations from party group lines in the present European Parliament, using a total of 1,370 roll call votes. The study confirms previous findings according to which party groups in the EP show (surprisingly high levels of cohesion. In addition and notwithstanding that, it reveals the circumstances under which MEPs and their national delegations are more likely to defect. Among other factors, it was analysed how the nature of the candidate selection process, the electoral system, and the relationships between MEPs and their home parties influence these defections. Assuming that MEPs have three different goals (re-election, office, and policy and want to first of all secure re-election, one can theoretically expect that those MEPs whose chances of re-election are more dependent on national parties than others’ (due to their specific candidate selection process or their relationship to their home party are more willing to vote against the party group line, if a conflict between party group and national party emerges. Empirically, this is confirmed. In other words, MEPs in general are very well aware of their specific situation. They know who deserves their primary attention and they act accordingly.

  11. The yield of essential oils in Melaleuca alternifolia (Myrtaceae is regulated through transcript abundance of genes in the MEP pathway.

    Directory of Open Access Journals (Sweden)

    Hamish Webb

    Full Text Available Medicinal tea tree (Melaleuca alternifolia leaves contain large amounts of an essential oil, dominated by monoterpenes. Several enzymes of the chloroplastic methylerythritol phosphate (MEP pathway are hypothesised to act as bottlenecks to the production of monoterpenes. We investigated, whether transcript abundance of genes encoding for enzymes of the MEP pathway were correlated with foliar terpenes in M. alternifolia using a population of 48 individuals that ranged in their oil concentration from 39 -122 mg x g DM(-1. Our study shows that most genes in the MEP pathway are co-regulated and that the expression of multiple genes within the MEP pathway is correlated with oil yield. Using multiple regression analysis, variation in expression of MEP pathway genes explained 87% of variation in foliar monoterpene concentrations. The data also suggest that sesquiterpenes in M. alternifolia are synthesised, at least in part, from isopentenyl pyrophosphate originating from the plastid via the MEP pathway.

  12. MEP solution for a minimal climate model: success and limitation of a variational problem

    Directory of Open Access Journals (Sweden)

    S. Pascale

    2011-05-01

    Full Text Available Maximum Entropy Production conjecture (MEP is applied to a minimal four-box model of climate which accounts for both horizontal and vertical material heat fluxes. It is shown that, under condition of fixed insolation, a MEP solution is found with reasonably realistic temperature and heat fluxes, thus generalising results from independent two-box horizontal or vertical models. It is also shown that the meridional and the vertical entropy production terms are independently involved in the maximisation and thus MEP can be applied to each subsystem with fixed boundary conditions. We then extend the four-box model by increasing its number of degrees of freedom, and test its realism by comparing it with a GCM output. An order-of-magnitude evaluation of contributions to the material entropy production (≈50 mW m−2 K−1 due to horizontal and vertical processes within the climate system is carried out by using ad hoc temperature fields. It turns out that approximately 40 mW m−2 K−1 is the entropy production due to vertical heat transport and 5–7 mW m−2 K−1 to horizontal heat transport. A MEP solution is found which is fairly realistic as far as the horizontal large scale organisation of the surface climate is concerned whereas the vertical structure looks to be unrealistic and presents seriously unstable features. Finally a more general problem is investigated in which the longwave transmissivity is varied simultaneously with the temperature. This leads to a MEP solution characterised by a much warmer climate, with very vigorous vertical heat fluxes, in which the atmosphere is opaque to longwave radiation. A critical discussion about how to interpret MEP and how to apply it in a physically correct way concludes the paper.

  13. Characterization of three putative xylulose 5-phosphate/fructose 6-phosphate phosphoketolases in the cyanobacterium Anabaena sp. PCC 7120.

    Science.gov (United States)

    Moriyama, Takashi; Tajima, Naoyuki; Sekine, Kohsuke; Sato, Naoki

    2015-01-01

    Xylulose 5-phosphate/fructose 6-phosphate phosphoketolase (Xfp) is a key enzyme in the central carbohydrate metabolism in heterofermentative bacteria, in which enzymatic property of Xfps is well characterized. This is not the case in other microbes. The cyanobacterium Anabaena sp. PCC 7120 possesses three putative genes encoding Xfp, all1483, all2567, and alr1850. We purified three putative Xfps as recombinant proteins. The results of gel filtration indicated that these proteins form homomultimer complex. All1483 and All2567 showed phosphoketolase activity, whereas Alr1850 did not show the activity. Kinetic analyses demonstrated that substrates, fructose 6-phosphate and inorganic phosphate, are cooperatively bound to enzymes positively and negatively, respectively.

  14. Cloning and Expression Analysis of MEP Pathway Enzyme-encoding Genes in Osmanthus fragrans

    Directory of Open Access Journals (Sweden)

    Chen Xu

    2016-09-01

    Full Text Available The 2-C-methyl-d-erythritol 4-phosphate (MEP pathway is responsible for the biosynthesis of many crucial secondary metabolites, such as carotenoids, monoterpenes, plastoquinone, and tocopherols. In this study, we isolated and identified 10 MEP pathway genes in the important aromatic plant sweet osmanthus (Osmanthus fragrans. Multiple sequence alignments revealed that 10 MEP pathway genes shared high identities with other reported proteins. The genes showed distinctive expression profiles in various tissues, or at different flower stages and diel time points. The qRT-PCR results demonstrated that these genes were highly expressed in inflorescences, which suggested a tissue-specific transcript pattern. Our results also showed that OfDXS1, OfDXS2, and OfHDR1 had a clear diurnal oscillation pattern. The isolation and expression analysis provides a strong foundation for further research on the MEP pathway involved in gene function and molecular evolution, and improves our understanding of the molecular mechanism underlying this pathway in plants.

  15. Combination of Entner-Doudoroff pathway with MEP increases isoprene production in engineered Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Huaiwei Liu

    Full Text Available Embden-Meyerhof pathway (EMP in tandem with 2-C-methyl-D-erythritol 4-phosphate pathway (MEP is commonly used for isoprenoid biosynthesis in E. coli. However, this combination has limitations as EMP generates an imbalanced distribution of pyruvate and glyceraldehyde-3-phosphate (G3P. Herein, four glycolytic pathways-EMP, Entner-Doudoroff Pathway (EDP, Pentose Phosphate Pathway (PPP and Dahms pathway were tested as MEP feeding modules for isoprene production. Results revealed the highest isoprene production from EDP containing modules, wherein pyruvate and G3P were generated simultaneously; isoprene titer and yield were more than three and six times higher than those of the EMP module, respectively. Additionally, the PPP module that generates G3P prior to pyruvate was significantly more effective than the Dahms pathway, in which pyruvate production precedes G3P. In terms of precursor generation and energy/reducing-equivalent supply, EDP+PPP was found to be the ideal feeding module for MEP. These findings may launch a new direction for the optimization of MEP-dependent isoprenoid biosynthesis pathways.

  16. Central European MEPs as Agents of Two Principals Party Cohesion in the European Parliament after Enlargement

    Directory of Open Access Journals (Sweden)

    Bíró-Nagy, András

    2016-10-01

    Full Text Available This paper investigates the impact of Central European MEPs on party cohesion in the European Parliament. By applying the principal-agent theory, it is also analyzed how loyal are the MEPs of the Czech Republic, Hungary, Poland, Slovakia and Slovenia to their European political groups and national parties. The empirical research carried out in this study demonstrates that the Central European MEPs have not brought more division to their political groups, but have been loyal members of their European parties. The Central European MEPs have not weakened the cohesion of the EP party groups, but party cohesion was even further strengthened between 2004 and 2014. Cohesion is the strongest in the biggest parliamentary groups. EPP and S&D set the direction for most politicians on most occasions. Clear ’rebel’ cases, when national parties as a whole went against their European political groups are not more than 2-3 percent of all votes in the two biggest European political families. National parties have a bigger room of maneuver in the smaller political groups. In ECR and GUE-NGL the difference between loyalty to the national party and the European party group is significantly higher than in EPP and S&D.

  17. 75 FR 33766 - Manufacturing Extension Partnership (MEP) Availability of Funds for Projects To Develop Client...

    Science.gov (United States)

    2010-06-15

    ... business models and deployment strategies that integrate two or more of the MEP Strategic Growth Areas. The... Funds for Projects To Develop Client Engagement or Business Models and Deployment Strategies That... develop client engagement or business models and deployment strategies that integrate two or more of...

  18. How Reproducible Are Transcranial Magnetic Stimulation-Induced MEPs in Subacute Stroke?

    NARCIS (Netherlands)

    Hoonhorst, Maurits H. W. J.; Kollen, Boudewijn J.; van den Berg, Peter S. P.; Emmelot, Cornelis H.; Kwakkel, Gert

    2014-01-01

    Purpose: Motor evoked potentials (MEPs) and total motor conduction time (TMCT) induced by transcranial magnetic stimulation (TMS) are used to make assumptions about the prognosis of motor outcome after stroke. Understanding the different sources of variability is fundamental to the concept of reliab

  19. Conserved YjgF protein family deaminates reactive enamine/imine intermediates of pyridoxal 5'-phosphate (PLP)-dependent enzyme reactions

    National Research Council Canada - National Science Library

    Lambrecht, Jennifer A; Flynn, Jeffrey M; Downs, Diana M

    2012-01-01

    .... Our data support the conclusion that YjgF proteins have enamine/imine deaminase activity and accelerate the release of ammonia from reactive enamine/imine intermediates of the pyridoxal 5'-phosphate...

  20. Effect of medium acidity on the thermodynamics and kinetics of the reaction of pyridoxal 5'-phosphate with isoniazid in an aqueous solution

    Science.gov (United States)

    Gamov, G. A.; Zavalishin, M. N.; Usacheva, T. R.; Sharnin, V. A.

    2017-05-01

    Thermodynamic characteristics of the formation of the Schiff base between isoniazid and pyridoxal 5'-phosphate in an aqueous solution at different pH values of a medium are determined by means of spectrophotometry and calorimetric titration. The process kinetics is studied spectrophotometrically, and the reaction rate constants for the formation of the imine at different acidities of a medium are determined. Biochemical aspects of the binding of pyridoxal 5'-phosphate into stable compounds are discussed.

  1. Intraoperative tractography and motor evoked potential (MEP) monitoring in surgery for gliomas around the corticospinal tract.

    Science.gov (United States)

    Maesawa, Satoshi; Fujii, Masazumi; Nakahara, Norimoto; Watanabe, Tadashi; Wakabayashi, Toshihiko; Yoshida, Jun

    2010-07-01

    Our goal is to indicate the importance of combining intraoperative tractography with motor-evoked potential (MEP) monitoring for glioma surgery in motor eloquent areas. Tumor removal was performed in 28 patients with gliomas in and around the corticospinal tract (CST), in an operation theater equipped with an integrated high-field intraoperative magnetic resonance imaging and a neuronavigation system. Diffusion-tensor imaging-based tractography of the CST was implemented preoperatively and intraoperatively. When the surgically manipulated area came close to the corticospinal pathway, MEP responses were elicited by subcortical stimulation. Responsive areas were compared with the locations of fibers traced by preoperative and intraoperative tractography. Imaging and functional outcomes were reviewed. Intraoperative tractography demonstrated significant inward or outward shift during surgery. MEP responses were observed around the tract at various intensities, and the distance between MEP responsive sites and intraoperative tractography was significantly correlated with the stimulation intensity (P < 0.01). The distance from preoperative tractography was not correlated. A more than subtotal resection was achieved in 24 patients (85.7%). Transient motor deterioration was seen in 12 patients (42.8%), and a permanent deficit was seen in 1 patient (3.5%). We found that intraoperative tractography demonstrated the location of the CST more accurately than preoperative tractography. The results of the linear regression between distance and stimulation intensity were informative for guiding approaches to tumor remnants without impinging on the CST. The combination of intraoperative tractography and MEP monitoring can enhance the quality of surgery for gliomas in motor eloquent areas. Copyright © 2010 Elsevier Inc. All rights reserved.

  2. Facilitation of motor evoked potentials (MEPs) in first dorsal interosseous (FDI) muscle is dependent on different motor images.

    Science.gov (United States)

    Yahagi, S; Kasai, T

    1998-10-01

    We investigated changes in motor evoked potentials (MEPs) to explain why mental practice can improve motor performance. MEPs were recorded from right and left first dorsal interosseous (FDI) muscles of 9 normal, right-handed subjects during different motor images of index finger movement: (1) rest, (2) flexion, (3) abduction, (4) extension. A paired t test was used to compare differences of stimulus intensities and MEP amplitudes among conditions. MEP amplitudes significantly increased in both FDI muscles during motor images of flexion and abduction but not of extension. Moreover, MEP amplitudes were larger in flexion than in abduction. These differences were proportional to the amount of real EMG discharge of FDI muscle in the selected direction of index finger movement. With regard to right-left differences, MEP amplitudes in the right FDI muscle were larger than those in the left. The primary motor cortex plays a role in the mental representation of motor acts. Furthermore, the amount of corticomotoneuronal cell activity is affected by the different motor images utilizing the same muscle. Right-left difference of MEP amplitude supports the view of left-hemisphere dominance for motor programming as an aspect of normal brain function among right-handers.

  3. Looking at Ankara from Strasbourg: An Empirical Assessment of MEPs' Voting on and Framing of Turkey

    OpenAIRE

    2013-01-01

    this article examines the way in which the Members of the European Parliament (MEPS) frame Turkey and how this affects their voting stance towards Ankara in the parliamentary debates. Recent studies (Baldwin and Widgrén 2005; Braghiroli 2012; Canan-Sokullu 2011) have demonstrated that the debate on Turkey’s European Union (EU) membership produces a very divisive impact on the voting dynamics and voting alignments in the European Parliament (EP) in the light of its nationa...

  4. Prior history of FDI muscle contraction: different effect on MEP amplitude and muscle activity.

    Science.gov (United States)

    Talis, V L; Kazennikov, O V; Castellote, J M; Grishin, A A; Ioffe, M E

    2014-03-01

    Motor evoked potentials (MEPs) in the right first dorsal interosseous (FDI) muscle elicited by transcranial magnetic stimulation of left motor cortex were assessed in ten healthy subjects during maintenance of a fixed FDI contraction level. Subjects maintained an integrated EMG (IEMG) level with visual feedback and reproduced this level by memory afterwards in the following tasks: stationary FDI muscle contraction at the level of 40 ± 5 % of its maximum voluntary contraction (MVC; 40 % task), at the level of 20 ± 5 % MVC (20 % task), and also when 20 % MVC was preceded by either no contraction (0-20 task), by stronger muscle contraction (40-20 task) or by no contraction with a previous strong contraction (40-0-20 task). The results show that the IEMG level was within the prescribed limits when 20 and 40 % stationary tasks were executed with and without visual feedback. In 0-20, 40-20, and 40-0-20 tasks, 20 % IEMG level was precisely controlled in the presence of visual feedback, but without visual feedback the IEMG and force during 20 % IEMG maintenance were significantly higher in the 40-0-20 task than those in 0-20 and 40-20 tasks. That is, without visual feedback, there were significant variations in muscle activity due to different prehistory of contraction. In stationary tasks, MEP amplitudes in 40 % task were higher than in 20 % task. MEPs did not differ significantly during maintenance of the 20 % level in tasks with different prehistory of muscle contraction with and without visual feedback. Thus, in spite of variations in muscle background activity due to different prehistory of contraction MEPs did not vary significantly. This dissociation suggests that the voluntary maintenance of IEMG level is determined not only by cortical mechanisms, as reflected by corticospinal excitability, but also by lower levels of CNS, where afferent signals and influences from other brain structures and spinal cord are convergent.

  5. Reconstruction and evaluation of the synthetic bacterial MEP pathway in Saccharomyces cerevisiae.

    Directory of Open Access Journals (Sweden)

    Siavash Partow

    Full Text Available Isoprenoids, which are a large group of natural and chemical compounds with a variety of applications as e.g. fragrances, pharmaceuticals and potential biofuels, are produced via two different metabolic pathways, the mevalonate (MVA pathway and the 2-C-methyl-D-erythritol 4-phosphate (MEP pathway. Here, we attempted to replace the endogenous MVA pathway in Saccharomyces cerevisiae by a synthetic bacterial MEP pathway integrated into the genome to benefit from its superior properties in terms of energy consumption and productivity at defined growth conditions. It was shown that the growth of a MVA pathway deficient S. cerevisiae strain could not be restored by the heterologous MEP pathway even when accompanied by the co-expression of genes erpA, hISCA1 and CpIscA involved in the Fe-S trafficking routes leading to maturation of IspG and IspH and E. coli genes fldA and fpr encoding flavodoxin and flavodoxin reductase believed to be responsible for electron transfer to IspG and IspH.

  6. The Integration of MEPs from Central and Eastern Europe into the European Parliament

    Directory of Open Access Journals (Sweden)

    Radko Hokovský

    2012-04-01

    Full Text Available This article evaluates the level of integration of Members of the European Parliament from Central and Eastern Europe in the European Parliament after the EU enlargements of 2004 and 2007. The main objective is to address the puzzle of how the European Parliament’s political groups could maintain or even increase their voting cohesion after the influx of a significantly large number of new MEPs coming from countries with different historical experience, socio-economic characteristics, and political and party systems. Three indicators of MEP integration are defined: integration into parliamentary leadership, integration into parliamentary work, and integration into voting patterns. The article uses data from the VoteWatch.eu website on MEPs’ activities and voting between the years 2004-2011, as well as data from official documents of the European Parliament and its political groups. Analysis of the data reveals that the new member states’ MEPs were significantly under-represented in parliamentary leadership and key legislative activities, despite the fact that their voting loyalty to their political groups was greater than that of their colleagues from older member states.

  7. Advances and Application of Microextraction by Packed Sorbent (MEPS)%填充吸着剂微萃取(MEPS)的发展及应用

    Institute of Scientific and Technical Information of China (English)

    傅若农

    2016-01-01

    目标物样品的制备在复杂基体分离和测定中是一个极为重要的步骤.近年来,样品制备的发展方向是小型化、自动化和高效化,最近10年出现了填充吸着剂微萃取(Microextraction by packed sorbent,MEPS),这是一种简单的快速在线进样技术,只需要少量样品和少量洗脱溶剂.简单介绍了MEPS技术,包括其构型、应用场合以及所使用的吸着剂.

  8. Molecular cloning and enzymological characterization of pyridoxal 5'-phosphate independent aspartate racemase from hyperthermophilic archaeon Thermococcus litoralis DSM 5473.

    Science.gov (United States)

    Washio, Tsubasa; Kato, Shiro; Oikawa, Tadao

    2016-09-01

    We succeeded in expressing the aspartate racemase homolog gene from Thermococcus litoralis DSM 5473 in Escherichia coli Rosetta (DE3) and found that the gene encodes aspartate racemase. The aspartate racemase gene consisted of 687 bp and encoded 228 amino acid residues. The purified enzyme showed aspartate racemase activity with a specific activity of 1590 U/mg. The enzyme was a homodimer with a molecular mass of 56 kDa and did not require pyridoxal 5'-phosphate as a coenzyme. The enzyme showed aspartate racemase activity even at 95 °C, and the activation energy of the enzyme was calculated to be 51.8 kJ/mol. The enzyme was highly thermostable, and approximately 50 % of its initial activity remained even after incubation at 90 °C for 11 h. The enzyme showed a maximum activity at a pH of 7.5 and was stable between pH 6.0 and 7.0. The enzyme acted on L-cysteic acid and L-cysteine sulfinic acid in addition to D- and L-aspartic acids, and was strongly inhibited by iodoacetic acid. The site-directed mutagenesis of the enzyme showed that the essential cysteine residues were conserved as Cys83 and Cys194. D-Forms of aspartic acid, serine, alanine, and valine were contained in T. litoralis DSM 5473 cells.

  9. Decrease in pyridoxal-5'-phosphate concentration and increase in pyridoxal concentration in rat plasma by 4'-O-methylpyridoxine administration.

    Science.gov (United States)

    Kobayashi, Daisuke; Yoshimura, Teruki; Johno, Atsushi; Ishikawa, Mika; Sasaki, Keiko; Wada, Keiji

    2015-07-01

    Food poisoning from Ginkgo biloba seeds can cause epilepsy because of a decrease in γ-aminobutyric acid (GABA) concentrations in the brain. We previously demonstrated that 4'-O-methylpyridoxine (MPN) is responsible for this observed toxicity of G biloba seeds; however, the mechanism for the decrease in GABA and plasma concentration profile of MPN has not been clarified. Our hypothesis is that MPN induces a decrease in vitamin B6 concentrations, resulting in a decrease in GABA concentration. This study aimed to characterize the plasma concentration profile of MPN and intrinsic vitamin B6 concentrations (pyridoxal [PL], PL-5'-phosphate [PLP], and 4-pyridoxic acid) using a rat model. Plasma concentrations of B6 vitamers after intravenous MPN administration (5 mg/kg) were determined using high-performance liquid chromatography with a fluorescence detector. The half-life of MPN (0.91 ± 0.05 hours) was shorter in rats than the previously reported value in humans. We found a significant decrease in the plasma concentration of PLP, an active form of vitamin B6, after MPN administration. We also observed an increase in plasma PL and 4-pyridoxic acid concentrations; the increase in PL concentration may be caused by either metabolism of MPN to PL or by MPN-mediated inhibition of PL kinase. The present study is the first in vivo study showing relatively rapid elimination of MPN in rats and a decrease in plasma PLP concentration caused by MPN. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Biosynthesis of ribose-5-phosphate and erythrose-4-phosphate in archaea: a phylogenetic analysis of archaeal genomes

    Directory of Open Access Journals (Sweden)

    Tim Soderberg

    2005-01-01

    Full Text Available A phylogenetic analysis of the genes encoding enzymes in the pentose phosphate pathway (PPP, the ribulose monophosphate (RuMP pathway, and the chorismate pathway of aromatic amino acid biosynthesis, employing data from 13 complete archaeal genomes, provides a potential explanation for the enigmatic phylogenetic patterns of the PPP genes in archaea. Genomic and biochemical evidence suggests that three archaeal species (Methanocaldococcus jannaschii, Thermoplasma acidophilum and Thermoplasma volcanium produce ribose-5-phosphate via the nonoxidative PPP (NOPPP, whereas nine species apparently lack an NOPPP but may employ a reverse RuMP pathway for pentose synthesis. One species (Halobacterium sp. NRC-1 lacks both the NOPPP and the RuMP pathway but may possess a modified oxidative PPP (OPPP, the details of which are not yet known. The presence of transketolase in several archaeal species that are missing the other two NOPPP genes can be explained by the existence of differing requirements for erythrose-4-phosphate (E4P among archaea: six species use transketolase to make E4P as a precursor to aromatic amino acids, six species apparently have an alternate biosynthetic pathway and may not require the ability to make E4P, and one species (Pyrococcus horikoshii probably does not synthesize aromatic amino acids at all.

  11. Large-Scale Domain Motions and Pyridoxal-5'-Phosphate Assisted Radical Catalysis in Coenzyme B12-Dependent Aminomutases

    Directory of Open Access Journals (Sweden)

    Amarendra Nath Maity

    2014-02-01

    Full Text Available Lysine 5,6-aminomutase (5,6-LAM and ornithine 4,5-aminomutase (4,5-OAM are two of the rare enzymes that use assistance of two vitamins as cofactors. These enzymes employ radical generating capability of coenzyme B12 (5'-deoxyadenosylcobalamin, dAdoCbl and ability of pyridoxal-5'-phosphate (PLP, vitamin B6 to stabilize high-energy intermediates for performing challenging 1,2-amino rearrangements between adjacent carbons. A large-scale domain movement is required for interconversion between the catalytically inactive open form and the catalytically active closed form. In spite of all the similarities, these enzymes differ in substrate specificities. 4,5-OAM is highly specific for D-ornithine as a substrate while 5,6-LAM can accept D-lysine and L-β-lysine. This review focuses on recent computational, spectroscopic and structural studies of these enzymes and their implications on the related enzymes. Additionally, we also discuss the potential biosynthetic application of 5,6-LAM.

  12. The effect of pyridoxal-5-phosphate on serum alanine aminotransferase activity in dogs suffering from canine babesiosis

    Directory of Open Access Journals (Sweden)

    E.C. Myburgh

    2009-09-01

    Full Text Available Accurate measurements of serum aminotransferase (ALT activity in dogs relies on the endogenous pro-enzyme pyridoxal 5-phosphate (P5P. The purpose of this study was to determine whether the exclusion of P5P from the analytical method causes an underestimation of serum ALT activity in dogs suffering from babesiosis and in those manifesting evidence of hepatocellular damage, and to determine if anorexia causes sufficient P5P depletion to affect in vitro serum ALT activity. One-hundred-and-twenty healthy control dogs and 105 Babesia-infected dogs were included in the study. Two methods for ALT measurement were used: Method 1 included P5P, and Method 2 excluded P5P from the reaction mixture. Higher serum ALT activity was measured with Method 1 in the Babesia-infected dogs (P < 0.001, as well as in 14 dogs with suspected hepatocellular damage (P = 0.03. Duration of anorexia had no effect, irrespective of the method used. Although inclusion of P5P to the reaction mixture consistently resulted in higher measured serum ALT activity, the differences were too small to have led to incorrect diagnoses in the Babesia-infected dogs suspected of liver disease.

  13. Application of a Colorimetric Assay to Identify Putative Ribofuranosylaminobenzene 5'-Phosphate Synthase Genes Expressed with Activity in Escherichia coli

    Directory of Open Access Journals (Sweden)

    Bechard Matthew E.

    2003-01-01

    Full Text Available Tetrahydromethanopterin (H4MPT is a tetrahydrofolate analog originally discovered in methanogenic archaea, but later found in other archaea and bacteria. The extent to which H4MPT occurs among living organisms is unknown. The key enzyme which distinguishes the biosynthetic pathways of H4MPT and tetrahydrofolate is ribofuranosylaminobenzene 5'-phosphate synthase (RFAP synthase. Given the importance of RFAP synthase in H4MPT biosynthesis, the identification of putative RFAP synthase genes and measurement of RFAP synthase activity would provide an indication of the presence of H4MPT in untested microorganisms. Investigation of putative archaeal RFAP synthase genes has been hampered by the tendency of the resulting proteins to form inactive inclusion bodies in Escherichia coli. The current work describes a colorimetric assay for measuring RFAP synthase activity, and two modified procedures for expressing recombinant RFAP synthase genes to produce soluble, active enzyme. By lowering the incubation temperature during expression, RFAP synthase from Archaeoglobus fulgidus was produced in E. coli and purified to homogeneity. The production of active RFAP synthase from Methanothermobacter thermautotrophicus was achieved by coexpression of the gene MTH0830 with a molecular chaperone. This is the first direct biochemical identification of a methanogen gene that codes for an active RFAP synthase.

  14. Religion in European multi-level parliamentary politics: the policy preferences of British and Irish MEPs

    OpenAIRE

    Steven, Martin

    2013-01-01

    The United Kingdom (UK) and Republic of Ireland provide two distinctive cases for those investigating the role of religion in the politics and government of the European Union (EU). In particular, we can examine the relevance of faith-based values to the policy preferences of British and Irish Members of the European Parliament (MEPs) via an analysis of the responses to a Europe-wide survey questionnaire – the first of its kind, generating a representative cross-section of elite opinion. Acro...

  15. Efficient second strand cleavage during Holliday junction resolution by RuvC requires both increased junction flexibility and an exposed 5' phosphate.

    Directory of Open Access Journals (Sweden)

    Fekret Osman

    Full Text Available BACKGROUND: Holliday junction (HJ resolution is a critical step during homologous recombination. In Escherichia coli this job is performed by a member of the RNase H/Integrase superfamily called RuvC, whereas in Schizosaccharomyces pombe it has been attributed to the XPF family member Mus81-Eme1. HJ resolution is achieved through the sequential cleavage of two strands of like polarity at or close to the junction crossover point. RuvC functions as a dimer, whereas Mus81-Eme1 is thought to function as a dimer of heterodimers. However, in both cases the multimer contains two catalytic sites, which act independently and sequentially during the resolution reaction. To ensure that both strands are cleaved before the nuclease dissociates from the junction, the rate of second strand cleavage is greatly enhanced compared to that of the first. The enhancement of second strand cleavage has been attributed to the increased flexibility of the nicked HJ, which would facilitate rapid engagement of the second active site and scissile bond. Here we have investigated whether other properties of the nicked HJ are important for enhancing second strand cleavage. PRINCIPAL FINDINGS: A comparison of the efficiency of cleavage of nicked HJs with and without a 5' phosphate at the nick site shows that a 5' phosphate is required for most of the enhancement of second strand cleavage by RuvC. In contrast Mus81-Eme1 cleaves nicked HJs with and without a 5' phosphate with equal efficiency, albeit there are differences in cleavage site selection. CONCLUSIONS: Our data show that efficient HJ resolution by RuvC depends on the 5' phosphate revealed by incision of the first strand. This is a hitherto unappreciated factor in promoting accelerated second strand cleavage. However, a 5' phosphate is not a universal requirement since efficient cleavage by Mus81-Eme1 appears to depend solely on the increased junction flexibility that is developed by the first incision.

  16. Efficient second strand cleavage during Holliday junction resolution by RuvC requires both increased junction flexibility and an exposed 5' phosphate.

    Science.gov (United States)

    Osman, Fekret; Gaskell, Louise; Whitby, Matthew C

    2009-01-01

    Holliday junction (HJ) resolution is a critical step during homologous recombination. In Escherichia coli this job is performed by a member of the RNase H/Integrase superfamily called RuvC, whereas in Schizosaccharomyces pombe it has been attributed to the XPF family member Mus81-Eme1. HJ resolution is achieved through the sequential cleavage of two strands of like polarity at or close to the junction crossover point. RuvC functions as a dimer, whereas Mus81-Eme1 is thought to function as a dimer of heterodimers. However, in both cases the multimer contains two catalytic sites, which act independently and sequentially during the resolution reaction. To ensure that both strands are cleaved before the nuclease dissociates from the junction, the rate of second strand cleavage is greatly enhanced compared to that of the first. The enhancement of second strand cleavage has been attributed to the increased flexibility of the nicked HJ, which would facilitate rapid engagement of the second active site and scissile bond. Here we have investigated whether other properties of the nicked HJ are important for enhancing second strand cleavage. A comparison of the efficiency of cleavage of nicked HJs with and without a 5' phosphate at the nick site shows that a 5' phosphate is required for most of the enhancement of second strand cleavage by RuvC. In contrast Mus81-Eme1 cleaves nicked HJs with and without a 5' phosphate with equal efficiency, albeit there are differences in cleavage site selection. Our data show that efficient HJ resolution by RuvC depends on the 5' phosphate revealed by incision of the first strand. This is a hitherto unappreciated factor in promoting accelerated second strand cleavage. However, a 5' phosphate is not a universal requirement since efficient cleavage by Mus81-Eme1 appears to depend solely on the increased junction flexibility that is developed by the first incision.

  17. The role of 1-deoxy-d-xylulose-5-phosphate synthase and phytoene synthase gene family in citrus carotenoid accumulation.

    Science.gov (United States)

    Peng, Gang; Wang, Chunyan; Song, Song; Fu, Xiumin; Azam, Muhammad; Grierson, Don; Xu, Changjie

    2013-10-01

    Three 1-deoxy-D-xylulose-5-phosphate synthases (DXS) and three phytoene synthases (PSY) were identified in citrus, from Affymetrix GeneChip Citrus Genome Array, GenBank and public orange genome databases. Tissue-specific expression analysis of these genes was carried out on fruit peel and flesh, flower and leaf of Satsuma mandarin (Citrus unshiu Marc.) in order to determine their roles in carotenoid accumulation in different tissues. Expression of CitDXS1 and CitPSY1 was highest in all test tissues, while that of CitDXS2 and CitPSY2 was lower, and that of CitDXS3 and CitPSY3 undetectable. The transcript profiles of CitDXS1 and CitPSY1 paralleled carotenoid accumulation in flesh of Satsuma mandarin and orange (Citrus sinensis Osbeck) during fruit development, and CitPSY1 expression was also associated with carotenoid accumulation in peel, while the CitDXS1 transcript level was only weakly correlated with carotenoid accumulation in peel. Similar results were obtained following correlation analysis between expression of CitDXS1 and CitPSY1 and carotenoid accumulation in peel and flesh of 16 citrus cultivars. These findings identify CitPSY1 and CitDXS1 as the main gene members controlling carotenoid biosynthesis in citrus fruit. Furthermore, chromoplasts were extracted from flesh tissue of these citrus, and chromoplasts of different shape (spindle or globular), different size, and color depth were observed in different cultivars, indicating chromoplast abundance, number per gram tissue, size and color depth were closely correlated with carotenoid content in most cultivars. The relationship between carotenoid biosynthesis and chromoplast development was discussed. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  18. Interaction of thymidylate synthase with pyridoxal 5'-phosphate as studied by UV/visible difference spectroscopy and molecular modeling.

    Science.gov (United States)

    Santi, D V; Ouyang, T M; Tan, A K; Gregory, D H; Scanlan, T; Carreras, C W

    1993-11-09

    Pyridoxal 5'-phosphate (PLP) is an effective inhibitor of Lactobacillus casei thymidylate synthase (TS), competitive with respect to the nucleotide substrate dUMP (Chen et al., 1989). The UV/vis difference spectra of TS-PLP complexes show lambda max at 328 nm due to the specific interaction between Cys 198 of TS and PLP to form a thiohemiacetal, and lambda min at 388 nm due to depletion of free PLP. At high concentrations of PLP a new absorbance at 430 nm forms due to nonspecific Schiff base formation between PLP and lysine residues of the enzyme. Using spectral titration at 328 nm, the binding constant of the specific TS-PLP complex was determined to be 0.5 microM, and the stoichiometry was 2 mol of PLP/mol of TS dimer. The 328-nm absorbance of the TS-PLP complex can be competitively and completely eliminated by addition of dUMP or dTMP; this serves as a convenient binding assay for molecules which bind to the active site of TS. Analogs of PLP which do not contain the phosphate or the aldehyde moieties of PLP bound poorly to the enzyme, thus demonstrating the importance of these functional groups for binding. When treated with PLP, C244T TS, which contains the active site Cys 198 as the sole cysteine residue, showed the same properties as the wild-type enzyme. Treatment of the C198A and C198S mutants with PLP did not produce the absorbance at 328 nm assigned to thiohemiacetal formation.(ABSTRACT TRUNCATED AT 250 WORDS)

  19. MEP Latencies Predict the Neuromodulatory Effect of cTBS Delivered to the Ipsilateral and Contralateral Sensorimotor Cortex.

    Directory of Open Access Journals (Sweden)

    Gan Huang

    Full Text Available Recently, it was shown that the highly variable after-effect of continuous theta-burst stimulation (cTBS of the primary motor cortex (M1 can be predicted by the latency of motor-evoked potentials (MEPs recorded before cTBS. This suggests that at least part of this inter-individual variability is driven by differences in the neuronal populations preferentially activated by transcranial magnetic stimulation (TMS.Here, we recorded MEPs, TMS-evoked brain potentials (TEPs and somatosensory-evoked potentials (SEPs to investigate the effects of cTBS delivered over the primary sensorimotor cortex on both the ipsilateral and contralateral M1, and the ipsilateral and contralateral primary somatosensory cortex (S1.We confirm that the after-effects of cTBS can be predicted by the latency of MEPs recorded before cTBS. Over the hemisphere onto which cTBS was delivered, short-latency MEPs at baseline were associated with an increase of MEP magnitude (i.e. an excitatory effect of cTBS whereas late-latency MEPs were associated with reduced MEPs (i.e. an inhibitory effect of cTBS. This relationship was reversed over the contralateral hemisphere, indicating opposite effects of cTBS on the responsiveness of the ipsilateral and contralateral M1. Baseline MEP latencies also predicted changes in the magnitude of the N100 wave of TEPs elicited by stimulation of the ipsilateral and contralateral hemisphere, indicating that this TEP component is specifically dependent on the state of M1. Finally, there was a reverse relationship between MEP latency and the effects of cTBS on the SEP waveforms (50-130 ms, indicating that after-effects of cTBS on S1 are opposite to those on M1.Taken together, our results confirm that the variable after-effects of cTBS can be explained by differences in the neuronal populations activated by TMS. Furthermore, our results show that this variability also determines remote effects of cTBS in S1 and the contralateral hemisphere, compatible with

  20. Type I pyridoxal 5'-phosphate dependent enzymatic domains embedded within multimodular nonribosomal peptide synthetase and polyketide synthase assembly lines.

    Science.gov (United States)

    Milano, Teresa; Paiardini, Alessandro; Grgurina, Ingeborg; Pascarella, Stefano

    2013-10-23

    Pyridoxal 5'-phosphate (PLP)-dependent enzymes of fold type I, the most studied structural class of the PLP-dependent enzyme superfamily, are known to exist as stand-alone homodimers or homotetramers. These enzymes have been found also embedded in multimodular and multidomain assembly lines involved in the biosynthesis of polyketides (PKS) and nonribosomal peptides (NRPS). The aim of this work is to provide a proteome-wide view of the distribution and characteristics of type I domains covalently integrated in these assemblies in prokaryotes. An ad-hoc Hidden Markov profile was calculated using a sequence alignment derived from a multiple structural superposition of distantly related PLP-enzymes of fold type I. The profile was utilized to scan the sequence databank and to collect the proteins containing at least one type I domain linked to a component of an assembly line in bacterial genomes. The domains adjacent to a carrier protein were further investigated. Phylogenetic analysis suggested the presence of four PLP-dependent families: Aminotran_3, Beta_elim_lyase and Pyridoxal_deC, occurring mainly within mixed NRPS/PKS clusters, and Aminotran_1_2 found mainly in PKS clusters. Sequence similarity to the reference PLP enzymes with solved structures ranged from 24 to 42% identity. Homology models were built for each representative type I domain and molecular docking simulations with putative substrates were carried out. Prediction of the protein-protein interaction sites evidenced that the surface regions of the type I domains embedded within multienzyme assemblies were different from those of the self-standing enzymes; these structural features appear to be required for productive interactions with the adjacent domains in a multidomain context. This work provides a systematic view of the occurrence of type I domain within NRPS and PKS assembly lines and it predicts their structural characteristics using computational methods. Comparison with the corresponding stand

  1. Association of MEP1A gene variants with insulin metabolism in central European women with polycystic ovary syndrome.

    Science.gov (United States)

    Lam, Uyen D P; Lerchbaum, Elisabeth; Schweighofer, Natascha; Trummer, Olivia; Eberhard, Katharina; Genser, Bernd; Pieber, Thomas R; Obermayer-Pietsch, Barbara

    2014-03-10

    Polycystic ovary syndrome (PCOS) shows not only hyperandrogenemia, hirsutism and fertility problems, but also metabolic disturbances including obesity, cardiovascular events and type-2 diabetes. Accumulating evidence suggests some degree of inflammation associated with prominent aspects of PCOS. We aimed to investigate the association of genetic variants 3'UTR rs17468190 (G/T) of the inflammation-associated gene MEP1A (GenBank ID: NM_005588.2) with metabolic disturbances in PCOS and healthy control women. Genetic variants rs17468190 (G/T) of MEP1A gene were analyzed in 576 PCOS women and 206 controls by using the Taqman fluorogenic 5'-exonuclease assay. This polymorphism was tested for association with anthropometric, metabolic, hormonal, and functional parameters of PCOS. There was a borderline significant difference in genotype distribution between PCOS and control women (p=0.046). In overweight/obese PCOS patients, the variants rs17468190 (G/T) in the MEP1A gene are associated with glucose and insulin metabolism. In a dominant model, the GG genotype of the MEP1A gene was more strongly associated with insulin metabolism in overweight/obese PCOS women (body mass index, BMI>25 kg/m(2)), than in GT+TT genotypes. The MEP1A GG-carriers showed a significantly increased homeostatic model assessment - insulin resistance (HOMA-IR) (p=0.003), elevation of fasting insulin (p=0.004) and stimulated insulin (30 min, p<0.001; 60 min, p=0.009; 120 min, p=0.009) as well as triglyceride (p=0.032) levels. MEP1A is a possible target gene for disease modification in PCOS. It might contribute to the abnormalities of glucose metabolism and insulin sensitivity and serve as a diagnostic or therapeutic target gene for PCOS. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. TNF-α-induced down-regulation of CDX2 suppresses MEP1A expression in colitis

    DEFF Research Database (Denmark)

    Coskun, Mehmet; Olsen, Anders Krüger; Holm, Thomas Lindebo

    2012-01-01

    High levels of pro-inflammatory cytokines are linked to inflammatory bowel disease (IBD). The transcription factor Caudal-related homeobox transcription factor 2 (CDX2) plays a crucial role in differentiation of intestinal epithelium and regulates IBD-susceptibility genes, including meprin 1A (ME......A). The aim was to investigate the expression of CDX2 and MEP1A in colitis; to assess if they are regulated by tumor necrosis factor-α (TNF-α), and finally to reveal if CDX2 is involved in a TNF-α-induced down-regulation of MEP1A....

  3. Synthesis and biological evaluation with plant cells of new fosmidomycin analogues containing a benzoxazolone or oxazolopyridinone ring.

    Science.gov (United States)

    Courtois, Martine; Mincheva, Zoia; Andreu, Françoise; Rideau, Marc; Viaud-Massuard, Marie-Claude

    2004-12-01

    Fosmidomycin, 3-(N-formyl-N-hydroxyamido) propylphosphonic acid sodium salt, is an efficient inhibitor of 1-deoxy-D-xylulose-5-phosphate (DOXP) reductoisomerase, the second enzyme of the 2C-methyl-D-erythritol-4-phosphate (MEP) pathway notably present in Plasmodium species. We have synthesized a new series of analogues of fosmidomycin, containing a benzoxazolone, benzoxazolethione or oxazolopyridinone ring. As the MEP pathway is involved in the biosynthesis of all isoprenoids, accumulation of ajmalicine in Catharanthus roseus cells was chosen as a marker of monoterpenoid indole alkaloid (MIA) production. None of the twelve studied phosphonic esters 3 and phosphonic acids 4 affected periwinkle cell growth, but some of them (3c, 3e, 3g and 3h) showed a significant inhibition of ajmalicine accumulation: 45-85% at 125 microM. Surprisingly, this effect disappeared by conversion of 3c and 3g into the corresponding acids 4c and 4g, respectively.

  4. Microcomputer Materials from MEP. An Annotated Directory of Packages of Interest to Further Education. An Occasional Paper.

    Science.gov (United States)

    Gilbert, Leslie

    Designed to disseminate information to the post-school sector of United Kingdom education, this directory provides information on 50 microcomputer software packages developed by the Microelectronics Education Program (MEP) and available through educational publishers. Subject areas represented include accountancy, biology, business education,…

  5. The TORC1 effector kinase Npr1 fine tunes the inherent activity of the Mep2 ammonium transport protein.

    Science.gov (United States)

    Boeckstaens, Mélanie; Llinares, Elisa; Van Vooren, Pascale; Marini, Anna Maria

    2014-01-01

    The TORC1 complex controls cell growth upon integrating nutritional signals including amino-acid availability. TORC1 notably adapts the plasma membrane protein content by regulating arrestin-mediated endocytosis of amino-acid transporters. Here we demonstrate that TORC1 further fine tunes the inherent activity of the ammonium transport protein, Mep2, a yeast homologue of mammalian Rhesus factors, independently of arrestin-mediated endocytosis. The TORC1 effector kinase Npr1 and the upstream TORC1 regulator Npr2 control Mep2 transport activity by phospho-silencing a carboxy-terminal autoinhibitory domain. Under poor nitrogen supply, Npr1 enables Mep2 S457 phosphorylation and thus ammonium transport activity. Supplementation of the preferred nitrogen source glutamine leads to Mep2 inactivation and instant S457 dephosphorylation via plasma membrane Psr1 and Psr2 redundant phosphatases. This study underscores that TORC1 also adjusts nutrient permeability to regulate cell growth in a fast and flexible response to environmental perturbation, establishing a hierarchy in the transporters to be degraded, inactivated or maintained active at the plasma membrane.

  6. Microcomputer Materials from MEP. An Annotated Directory of Packages of Interest to Further Education. An Occasional Paper.

    Science.gov (United States)

    Gilbert, Leslie

    Designed to disseminate information to the post-school sector of United Kingdom education, this directory provides information on 50 microcomputer software packages developed by the Microelectronics Education Program (MEP) and available through educational publishers. Subject areas represented include accountancy, biology, business education,…

  7. Synthesis of C5 Phosphate Salt%阿朴酯关键中间体 C5磷盐的合成

    Institute of Scientific and Technical Information of China (English)

    刘笑; 吕国锋; 黄国东

    2016-01-01

    β-阿朴-8’-胡萝卜素的应用越来越广,诸多的合成方法各有优缺点,采用C25+C5的合成路线,其关键中体间C5磷盐的合成是一个瓶颈,本文以2-乙烯基丙腈为原料经乙醇为溶剂氰基醇解酯化,溴代后与亚磷酸三乙酯成盐得到C5磷盐纯度达98.70%,总收率达49.80%,具有工艺路线短、原料易得、反应条件温和、收率高的优点。%β-Apo-8 ’-Carotenoic Acid Ethyl Ester has been more widely used today .There are many methods for synthesis of it and each has its advantages and disadvantages.One way is employing C25+C5 to prepare.However, as the key intermediate , the synthesis of C5 phosphate salt is still a bottle-neck issue.C5 phosphate salt was prepared as follows: cyano alcoholysis esterification first took place with 2-ethyl-3-butenenitril as the reactant and ethyl alcohol as the solvent, after bromination, it went to react with triethyl phosphate to produce C5 phosphate salt.It turned out that the purity of the product reached as high as 98.70% and total yield exceeded 49.80%. This approach was characterized by short process.The raw material had the advantages of easy to get , mild reaction conditions and high yield.

  8. [Properties of 2,5-diamino-4-oxy-6-ribosylaminopyrimidine-5'- phosphate reductase, a enzyme of the second stage of flavinogenesis in Pichia guilliermondii yeasts].

    Science.gov (United States)

    Logvinenko, E M; Shavlovskiĭ, G M; Zakal'skiĭ, A E; Kontorovskaia, N Iu

    1989-01-01

    2,5-Diamino-4-oxy-6-ribosylaminopyrimidine-5'-phosphate reductase has been isolated from cells of Pichia guilliermondii and subjected to 20-fold purification by treating extracts with streptomycin sulphate, frationating proteins (NH4)2SO4 at 45-75% of saturation and chromatography on blue sepharose CL-6B. The use of gel filtration through Sephadex G-150 and chromatography on DEAE-cellulose proved to be less effective for the enzyme purification. It has been established that it is 2,5-diamino-4-oxy-6-ribosylaminopyrimidine-5-phosphate but not its dephosphorylated form that is the substrate of the given reductase; Km is equal to 7.10(-5) M. The reaction proceeds in the presence of NADPH or NADH. The enzyme affinity to NADPH (Km = 4.7.10(-5) M) is approximately one order higher than that to NADPH (Km = 5.5.10(-4) M). The enzyme manifests the optimum of action at pH 7.2 and the temperature of 37 degrees C; the molecular weight is 140 kD. EDTA as well as flavins in the concentration of 1.10(-3) M exert no effect on the reductase activity. The enzyme is labile at 4 degrees C and is inactivated in the frozen state at -15 degrees C. The 2.5-diamino-4-oxy-6-ribosylaminopyrimidine-5'-phosphate reductase has been also revealed in Torulopsis candida, Debaryomyces klöckeri, Schwanniomyces occidentalis, Eremothecium ashbyii (flavinogenic species) and Candida utilis. Aspergillus nidulans, Neurospora crassa (nonflavinogenic species). The synthesis of this enzyme contrary to other enzymes of the riboflavin biosynthesis is not regulated in flavinogenic yeast by iron ions.

  9. Perinatal hypophosphatasia presenting as neonatal epileptic encephalopathy with abnormal neurotransmitter metabolism secondary to reduced co-factor pyridoxal-5'-phosphate availability.

    Science.gov (United States)

    Balasubramaniam, Shanti; Bowling, Frank; Carpenter, Kevin; Earl, John; Chaitow, Jeffrey; Pitt, James; Mornet, Etienne; Sillence, David; Ellaway, Carolyn

    2010-12-01

    We describe two neonates presenting with perinatal hypophosphatasia and severe epileptic encephalopathy resulting in death. Both had increased levels of urinary vanillactate, indicating functional deficiency of aromatic amino acid decarboxylase, a pyridoxal-5-phosphate (PLP)-dependent enzyme required for dopamine and serotonin biosynthesis. Clinical findings and results of subsequent metabolic investigations were consistent with secondary pyridoxine-deficient encephalopathy. These patients highlight the importance of tissue non-specific alkaline phosphatase in the neuronal PLP-dependent metabolism of neurotransmitters. In addition, the disturbance of PLP metabolism appears to underlie the predominant neurological presentation in our patients. We recommend the measurement of serum alkaline phosphatase (ALP) during the assessment of perinatal seizures.

  10. Looking at Ankara from Strasbourg: An Empirical Assessment of MEPs' Voting on and Framing of Turkey

    Directory of Open Access Journals (Sweden)

    Stefano Braghiroli

    2013-12-01

    Full Text Available this article examines the way in which the Members of the European Parliament (MEPS frame Turkey and how this affects their voting stance towards Ankara in the parliamentary debates. Recent studies (Baldwin and Widgrén 2005; Braghiroli 2012; Canan-Sokullu 2011 have demonstrated that the debate on Turkey’s European Union (EU membership produces a very divisive impact on the voting dynamics and voting alignments in the European Parliament (EP in the light of its national and political significance. The parliamentary positions on the ‘Turkey discourse’ range from enthusiastic support to open Turkophobia. What is even more striking is the wide variety of individual positions generally identifiable within the same political/ideological area. To what extent are meps’ different perceptions and representations of Turkey reflected in the way they vote when Turkey is at stake in the EP? And, what is the impact of this state of things on groups’ internal cohesion? This study addresses these two fundamental questions using two different sources of data. Elite survey data is used in order to capture MEPS’ perceptions of Turkey, while meps’ voting behavior is assessed in the light of the expressed votes.

  11. Expression and function of androgen receptor coactivator p44/Mep50/WDR77 in ovarian cancer.

    Directory of Open Access Journals (Sweden)

    Martin Ligr

    Full Text Available Hormones, including estrogen and progesterone, and their receptors play an important role in the development and progression of ovarian carcinoma. Androgen, its receptor and coactivators have also been implicated in these processes. p44/Mep50/WDR77 was identified as a subunit of the methylosome complex and lately characterized as a steroid receptor coactivator that enhances androgen receptor as well as estrogen receptor-mediated transcriptional activity in a ligand-dependent manner. We previously described distinct expression and function of p44 in prostate, testis, and breast cancers. In this report, we examined the expression and function of p44 in ovarian cancer. In contrast to findings in prostate and testicular cancer and similar to breast cancer, p44 shows strong cytoplasmic localization in morphologically normal ovarian surface and fallopian tube epithelia, while nuclear p44 is observed in invasive ovarian carcinoma. We observed that p44 can serve as a coactivator of both androgen receptor (AR and estrogen receptor (ER in ovarian cells. Further, overexpression of nuclear-localized p44 stimulates proliferation and invasion in ovarian cancer cells in the presence of estrogen or androgen. These findings strongly suggest that p44 plays a role in mediating the effects of hormones during ovarian tumorigenesis.

  12. Enhanced pyridoxal 5'-phosphate synthetic enzyme immunoreactivities do not contribute to GABAergic inhibition in the rat hippocampus following pilocarpine-induced status epilepticus.

    Science.gov (United States)

    Kwak, S-E; Kim, J-E; Kim, D-W; Kwon, O-S; Choi, S-Y; Kang, T-C

    2009-03-31

    To comprehend the role of pyridoxal 5'-phosphate (PLP) in epilepsy or seizure, we investigated whether the expressions of two PLP synthetic enzymes (pyridoxal kinase, PLK; pyridoxine-5'-phosphate oxidase, PNPO) are altered in the hippocampus and whether changes in paired-pulse responses in the hippocampus are associated with altered PLP synthetic enzyme expressions following status epilepticus (SE). PLK and PNPO immunoreactivities were significantly increased in the rat hippocampus accompanied by reductions in paired-pulse inhibition at 1 day and 1 week after SE. Four weeks after SE, PLK and PNPO immunoreactivities in dentate granule cells were similar to those in control animals, while their immunoreactivities were markedly reduced in Cornu Ammonis 1 (CA1) pyramidal cells due to neuronal loss. Linear regression analysis identified a direct proportional relationship between PLK/PNPO immunoreactivity and normalized population spike amplitude ratio in the dentate gyrus and the CA1 region as excluded the data obtained from 4 weeks after SE. These findings indicate that the upregulation of PLK and PNPO immunoreactivities in principal neurons may not be involved in gamma-aminobutyric acid (GABA)ergic inhibition, but rather in enhanced excitability during epileptogenic periods.

  13. Preincubation of serum aspartate aminotransferase with pyridoxal 5'-phosphate in the SMAC: comparison with revised DuPont aca method and recommended IFCC method.

    Science.gov (United States)

    Garber, C C; Feldbruegge, D H; Hoessel, M

    1981-04-01

    The method for continuous-flow assay of aspartate aminotransferase with the Technicon SMAC was modified to include preincubation of the serum enzyme with pyridoxal 5'-phosphate, to be consistent with the recommendations of IFCC and the Standards Committee of AACC. Preliminary estimates of the imprecision of the modified method on SMAC gave day-to-day standard deviations of 5.3 U/L at mean of 48 U/L (n = 66) and 6.2 U/L at 155 U/L (n = 61). Added bilirubin, sodium pyruvate, ascorbic acid, and endogenous lipids did not interfere. Comparison of results for 50 samples by this method with those by the manual IFCC method gave y = 1.1113x - 0.3 U/L, Sy/x = 4.4 U/L, and r = 0.997. Similar data are presented for the revised AST method for the DuPont aca discrete analyzer. Clinical data show that AST activities increase by as much as 200% when the serum is preincubated with pyridoxal 5'-phosphate.

  14. Identifying Episodes of Back Pain Using Medical Expenditures Panel Survey (MEPS) Data: Patient Experience, Use of Services, and Chronicity

    Science.gov (United States)

    Monica, Smith

    2010-01-01

    Objective To explore the correspondence between “episodes of pain” and “episodes of care” for individuals with back pain. Data Source Secondary analysis of Medical Expenditures Panel Survey (MEPS) 2-year longitudinal data. Study Design Individual use and utilization of back pain services were examined across ambulatory settings and providers, and linked to MEPS medical condition data to identify individuals with back pain who do not use, or who delay or discontinue utilization of health services for back pain. Data Collection/Extraction Methods Episodes-of-care and episodes-of-pain were approximated through round-by-round temporal mapping of MEPS back pain utilization events data and medical conditions data. Principal Findings Of 10,193 individuals with back pain, approximately one fifth did not actively seek care for their back pain. Utilization of services for back pain (episodes-of-care) does not always correspond with an individual’s full experience of back pain (episodes-of-pain). Upwards of 20% of MEPS respondents who use services for some back pain episodes, reported additional episodes for which they do not use services. Conclusions These findings suggest that other longitudinal studies based only on data that reflect service use, e.g., claims data, may incorrectly infer the nature of back pain and back pain episodes. Many individuals report ongoing back pain that continues beyond their episodes-of-care, and many individuals with persistent back pain may use prescription drugs, medical services, and other health services only intermittently. PMID:21036278

  15. Structural modeling and docking studies of ribose 5-phosphate isomerase from Leishmania major and Homo sapiens: a comparative analysis for Leishmaniasis treatment.

    Science.gov (United States)

    Capriles, Priscila V S Z; Baptista, Luiz Phillippe R; Guedes, Isabella A; Guimarães, Ana Carolina R; Custódio, Fabio L; Alves-Ferreira, Marcelo; Dardenne, Laurent E

    2015-02-01

    Leishmaniases are caused by protozoa of the genus Leishmania and are considered the second-highest cause of death worldwide by parasitic infection. The drugs available for treatment in humans are becoming ineffective mainly due to parasite resistance; therefore, it is extremely important to develop a new chemotherapy against these parasites. A crucial aspect of drug design development is the identification and characterization of novel molecular targets. In this work, through an in silico comparative analysis between the genomes of Leishmania major and Homo sapiens, the enzyme ribose 5-phosphate isomerase (R5PI) was indicated as a promising molecular target. R5PI is an important enzyme that acts in the pentose phosphate pathway and catalyzes the interconversion of d-ribose-5-phosphate (R5P) and d-ribulose-5-phosphate (5RP). R5PI activity is found in two analogous groups of enzymes called RpiA (found in H. sapiens) and RpiB (found in L. major). Here, we present the first report of the three-dimensional (3D) structures and active sites of RpiB from L. major (LmRpiB) and RpiA from H. sapiens (HsRpiA). Three-dimensional models were constructed by applying a hybrid methodology that combines comparative and ab initio modeling techniques, and the active site was characterized based on docking studies of the substrates R5P (furanose and ring-opened forms) and 5RP. Our comparative analyses show that these proteins are structural analogs and that distinct residues participate in the interconversion of R5P and 5RP. We propose two distinct reaction mechanisms for the reversible isomerization of R5P to 5RP, which is catalyzed by LmRpiB and HsRpiA. We expect that the present results will be important in guiding future molecular modeling studies to develop new drugs that are specially designed to inhibit the parasitic form of the enzyme without significant effects on the human analog.

  16. A higher number of TMS-elicited MEP from a combined hotspot improves intra- and inter-session reliability of the upper limb muscles in healthy individuals.

    Science.gov (United States)

    Bastani, Andisheh; Jaberzadeh, Shapour

    2012-01-01

    We aimed to determine, using transcranial magnetic stimulation (TMS), the number of elicited motor evoked potentials (MEPs) that induces the highest intra- and inter-sessions reliability for the extensor carpi radialis (ECR) and first dorsal interosseus (FDI) muscles. Twelve healthy subjects participated in this study on two separate days. Single pulse magnetic stimuli were triggered with Magstim 200(2) to obtain MEPs from the muscles of interest, with the subjects in a relaxed position. Reliability of MEP responses was investigated in three blocks of 5, 10 and 15 trials. The intra- and inter-session reliability of the MEPs' amplitudes and latencies were assessed using intraclass correlation coefficients (ICCs). Repeated measures ANOVA and paired t-tests revealed no significant time effect in the MEP amplitude and latency measurements (P>0.05). The ICCs indicated high intra-session reliability in the MEPs' amplitudes for the ECR and FDI muscles (0.77 to 0.99, 0.90 to 0.99, respectively) and latency (0.80 to 1.00, 0.75 to 0.97, respectively). The MEPs' amplitudes also had high inter-session reliability (0.84 to 0.97, 0.88 to 0.93, respectively), as did their latency (0.80 to 0.90, 0.75 to 0.97, respectively). Highest intra- and inter-session reliability was achieved for blocks of 10 and 15 trials. Our data suggest that intra- and inter-session comparisons should be performed using at least 10 MEPs in "combined hotspot" stimulation technique to ensure highest reliability.

  17. A higher number of TMS-elicited MEP from a combined hotspot improves intra- and inter-session reliability of the upper limb muscles in healthy individuals.

    Directory of Open Access Journals (Sweden)

    Andisheh Bastani

    Full Text Available We aimed to determine, using transcranial magnetic stimulation (TMS, the number of elicited motor evoked potentials (MEPs that induces the highest intra- and inter-sessions reliability for the extensor carpi radialis (ECR and first dorsal interosseus (FDI muscles. Twelve healthy subjects participated in this study on two separate days. Single pulse magnetic stimuli were triggered with Magstim 200(2 to obtain MEPs from the muscles of interest, with the subjects in a relaxed position. Reliability of MEP responses was investigated in three blocks of 5, 10 and 15 trials. The intra- and inter-session reliability of the MEPs' amplitudes and latencies were assessed using intraclass correlation coefficients (ICCs. Repeated measures ANOVA and paired t-tests revealed no significant time effect in the MEP amplitude and latency measurements (P>0.05. The ICCs indicated high intra-session reliability in the MEPs' amplitudes for the ECR and FDI muscles (0.77 to 0.99, 0.90 to 0.99, respectively and latency (0.80 to 1.00, 0.75 to 0.97, respectively. The MEPs' amplitudes also had high inter-session reliability (0.84 to 0.97, 0.88 to 0.93, respectively, as did their latency (0.80 to 0.90, 0.75 to 0.97, respectively. Highest intra- and inter-session reliability was achieved for blocks of 10 and 15 trials. Our data suggest that intra- and inter-session comparisons should be performed using at least 10 MEPs in "combined hotspot" stimulation technique to ensure highest reliability.

  18. Induction of apoptosis in HepG2 cells by polysaccharide MEP-II from the fermentation broth of Morchella esculenta.

    Science.gov (United States)

    Hu, Meili; Chen, Yan; Wang, Cui; Cui, Huali; Duan, Peilu; Zhai, Tianlong; Yang, Yuling; Li, Shaofei

    2013-01-01

    A novel polysaccharide, MEP-II, isolated from the fermentation broth of Morchella esculenta inhibited the proliferation of human hepatoma cell line (HepG2) through an apoptotic pathway. After HepG2 cells were treated with 150-600 μg MEP-II/ml, typical apoptotic characteristics including externalization of phosphatidylserine residues on the cell surface, nuclear fragmentation, chromatin condensation and cytoplasm shrinkage were observed. Furthermore, reactive oxygen species (ROS) burst and the collapse of mitochondrial membrane potential (Δψm) also occurred in HepG2 cells after incubation of 150-600 μg MEP-II/ml. The antioxidant, 1 mM N-acetyl-L-cysteine inhibited MEP-II-induced apoptosis, suggesting that ROS are the key mediators for MEP-II-induced apoptosis. MEP-II is therefore a potential anti-tumor agent that induces apoptosis of HepG2 cells through ROS generation.

  19. Investigating the cortical regions involved in MEP modulation in tDCS

    Directory of Open Access Journals (Sweden)

    Ricardo eSalvador

    2015-10-01

    Full Text Available Transcranial magnetic stimulation (TMS is used in several studies to evaluate cortical excitability changes induced by transcranial direct current stimulation (tDCS of the primary motor cortex. Interpretation of these results, however, is hindered by the very different spatial distribution of the electric field (E-field induced by the two techniques and by the different target neurons that they might act upon. In this study we used the finite element method to calculate the E-field distribution induced by TMS and tDCS in a realistically shaped model of a human head. A model of a commercially available figure-8 coil was placed over a position above the identified hand knob (HK region. We also modelled two configurations of bipolar tDCS montages with one of the electrodes placed over the HK and a return electrode over the contralateral orbital region. The electrodes over the HK were either rectangular in shape, with an area of 35cm2 or cylindrical with an area of π cm2 (1 cm radius. To compare the E-field distribution in TMS and the two tDCS models, average values of the E-field’s magnitude as well as the polar and azimuthal angle were investigated in the HK region and premotor areas. The results show that both techniques induce fields with different magnitudes and directions in the HK: the field in tDCS is predominantly perpendicular to the cortical surface, contrary to what happens in TMS where the field is mostly parallel to it. In the premotor areas, the magnitude of the E-field induced in TMS was well below the accepted threshold for MEP generation, 100 V/m. In tDCS, the magnitude of the field in these areas was comparable to that induced at the HK with a significant component perpendicular to the cortical surface. These results indicate that tDCS and TMS target preferentially different neuronal structures at the HK. Besides, they show that premotor areas may play a role in the tDCS-induced after effects on motor cortex excitability.

  20. Different Roles of the Mevalonate and Methylerythritol Phosphate Pathways in Cell Growth and Tanshinone Production of Salvia miltiorrhiza Hairy Roots

    Science.gov (United States)

    Yang, Dongfeng; Du, Xuhong; Liang, Xiao; Han, Ruilian; Liang, Zongsuo; Liu, Yan; Liu, Fenghua; Zhao, Jianjun

    2012-01-01

    Salvia miltiorrhiza has been widely used in the treatment of coronary heart disease. Tanshinones, a group of diterpenoids are the main active ingredients in S. miltiorrhiza. Two biosynthetic pathways were involved in tanshinone biosynthesis in plants: the mevalonate (MVA) pathway in the cytosol and the methylerythritol phosphate (MEP) pathway in the plastids. The 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) is the rate-limiting enzyme of the MVA pathway. The 1-deoxy-D-xylulose 5-phosphate synthase (DXS) and 1-deoxy-D-xylulose 5-phosphate reductoisomerase (DXR) are the key enzymes of the MEP pathway. In this study, to reveal roles of the MVA and the MEP pathways in cell growth and tanshinone production of S. miltiorrhiza hairy roots, specific inhibitors of the two pathways were used to perturb metabolic flux. The results showed that the MVA pathway inhibitor (mevinolin, MEV) was more powerful to inhibit the hairy root growth than the MEP pathway inhibitor (fosmidomycin, FOS). Both MEV and FOS could significantly inhibit tanshinone production, and FOS was more powerful than MEV. An inhibitor (D, L-glyceraldehyde, DLG) of IPP translocation strengthened the inhibitory effects of MEV and FOS on cell growth and tanshinone production. Application of MEV resulted in a significant increase of expression and activity of HMGR at 6 h, and a sharp decrease at 24 h. FOS treatment resulted in a significant increase of DXR and DXS expression and DXS activity at 6 h, and a sharp decrease at 24 h. Our results suggested that the MVA pathway played a major role in cell growth, while the MEP pathway was the main source of tanshinone biosynthesis. Both cell growth and tanshinone production could partially depend on the crosstalk between the two pathways. The inhibitor-mediated changes of tanshinone production were reflected in transcript and protein levels of genes of the MVA and MEP pathways. PMID:23209548

  1. Different roles of the mevalonate and methylerythritol phosphate pathways in cell growth and tanshinone production of Salvia miltiorrhiza hairy roots.

    Directory of Open Access Journals (Sweden)

    Dongfeng Yang

    Full Text Available Salvia miltiorrhiza has been widely used in the treatment of coronary heart disease. Tanshinones, a group of diterpenoids are the main active ingredients in S. miltiorrhiza. Two biosynthetic pathways were involved in tanshinone biosynthesis in plants: the mevalonate (MVA pathway in the cytosol and the methylerythritol phosphate (MEP pathway in the plastids. The 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR is the rate-limiting enzyme of the MVA pathway. The 1-deoxy-D-xylulose 5-phosphate synthase (DXS and 1-deoxy-D-xylulose 5-phosphate reductoisomerase (DXR are the key enzymes of the MEP pathway. In this study, to reveal roles of the MVA and the MEP pathways in cell growth and tanshinone production of S. miltiorrhiza hairy roots, specific inhibitors of the two pathways were used to perturb metabolic flux. The results showed that the MVA pathway inhibitor (mevinolin, MEV was more powerful to inhibit the hairy root growth than the MEP pathway inhibitor (fosmidomycin, FOS. Both MEV and FOS could significantly inhibit tanshinone production, and FOS was more powerful than MEV. An inhibitor (D, L-glyceraldehyde, DLG of IPP translocation strengthened the inhibitory effects of MEV and FOS on cell growth and tanshinone production. Application of MEV resulted in a significant increase of expression and activity of HMGR at 6 h, and a sharp decrease at 24 h. FOS treatment resulted in a significant increase of DXR and DXS expression and DXS activity at 6 h, and a sharp decrease at 24 h. Our results suggested that the MVA pathway played a major role in cell growth, while the MEP pathway was the main source of tanshinone biosynthesis. Both cell growth and tanshinone production could partially depend on the crosstalk between the two pathways. The inhibitor-mediated changes of tanshinone production were reflected in transcript and protein levels of genes of the MVA and MEP pathways.

  2. 植物MEP途径的代谢调控机制%Multiple Regulation Mechanisms of MEP Pathway in Plant

    Institute of Scientific and Technical Information of China (English)

    张松涛; 陈红丽; 崔红; 杨惠娟; 刘国顺

    2012-01-01

    Terpenoids metabolism is one of the most important pathways of secondary metabolism in plant. The regulatory mechanisms that modulate this metabolic route will determine plant growth and development, resistance, quality and other aspects. The terpene precursors are synthesized by the 2-C-Methyl-D-E-rythritol-4-Phosphate (MEP) pathway in plant plastids. Recent studies have shown that, many genes involved in MEP pathway are not only regulated by multiple genes encoding and the transcript level,but also by post-transcriptional mechanism. Post-transcriptional regulation is a novel regulation mechanism described recently for this way and the mechanism is not clear. We review here various regulatory mechanisms of MEP pathway in plant, especially the mechanism and signal molecular that may be involved in post-transcriptional regulation,which may provide the theory basis for the research of regulation in this pathway.%萜类代谢途径是植物中最重要的次生代谢途径之一,对其有效的调控决定着植物的生长发育、抗性及品质等各个方面.植物中类萜合成的前体物在质体中是由2-C-甲基-D-赤藓糖醇-4-磷酸(2-C-Methyl-D-Erythritol-4-Phosphate,MEP)途径合成的,MEP途径中的许多基因除了受到多基因编码和转录水平的调节外,还受到转录后调节机制的调节,而转录后调节是一种新发现的调节方式,其机制还不是很清楚.该文重点对近年来国内外有关植物MEP途径的多种调节方式,尤其是转录后调节的调节机制及其可能参与的信号分子方面的研究进展进行综述,为植物的MEP途径的代谢调控提供参考.

  3. Check-Testing of Manufacturer Self Reported Labeling Data& Compliance with MEPS

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Nan; Zhou, Nan; Zheng, Nina; Fridley, David; Wang, Ruohong; Egan, Christine

    2008-03-01

    China first adopted minimum energy performance standards (MEPS) in 1989. Today, there are standards for a wide range of domestic, commercial and selected industrial equipment. In 1999, China launched a voluntary endorsement label, which has grown to cover over 40 products including water-saving products. Further, in 2005, China started a mandatory energy information label that initially covered two products and in 2007 was extended to cover four products total including: air conditioners; household refrigerators; clothes washers; and unitary air conditioners. These programs have had an important impact in reducing the energy consumption of appliances in China. China has built up a strong infrastructure to develop and implement standards. Historically, however, the government's primary focus has been on the technical requirements for specifying efficiency performance. Less attention has been paid to monitoring and enforcement with a minimal commitment of resources and little expansion of administrative capacity in this area. Thus, market compliance with both mandatory standard and labeling programs has been questionable. Furthermore, actual energy savings have quite possibly been undermined as a result. The establishment of a regularized monitoring system for tracking compliance with the mandatory standard and energy information label programs in China is a major area for program improvement. Over the years, the Collaborative Labeling and Appliance Standards Program (CLASP) has partnered with several Chinese institutions to promote energy-efficient products in China. CLASP, together with its implementing partner Lawrence Berkeley National Laboratory (LBNL), has assisted China in developing and updating the above-mentioned standards and labeling programs. Because of the increasing need for the development of a monitoring system to track compliance with the standard, CLASP, with support from Japan's Ministry of Economy, Trade and Industry (METI) and the

  4. D-Ribulose 5-Phosphate 3-Epimerase: Functional and Structural Relationships to Members of the Ribulose-Phosphate Binding (beta/alpha)8-Barrel Superfamily

    Energy Technology Data Exchange (ETDEWEB)

    Akana,J.; Federov, A.; Federov, E.; Novak, W.; Babbitt, P.; Almo, S.; Gerlt, J.

    2006-01-01

    The 'ribulose phosphate binding' superfamily defined by the Structural Classification of Proteins (SCOP) database is considered the result of divergent evolution from a common ({beta}/{alpha}){sub 8}-barrel ancestor. The superfamily includes D-ribulose 5-phosphate 3-epimerase (RPE), orotidine 5'-monophosphate decarboxylase (OMPDC), and 3-keto-L-gulonate 6-phosphate decarboxylase (KGPDC), members of the OMPDC suprafamily, as well as enzymes involved in histidine and tryptophan biosynthesis that utilize phosphorylated metabolites as substrates. We now report studies of the functional and structural relationships of RPE to the members of the superfamily. As suggested by the results of crystallographic studies of the RPEs from rice and Plasmodium falciparum, the RPE from Streptococcus pyogenes is activated by Zn{sup 2+} which binds with a stoichiometry of one ion per polypeptide. Although wild type RPE has a high affinity for Zn{sup 2+} and inactive apoenzyme cannot be prepared, the affinity for Zn{sup 2+} is decreased by alanine substitutions for the two histidine residues that coordinate the Zn{sup 2+} ion (H34A and H67A); these mutant proteins can be prepared in an inactive, metal-free form and activated by exogenous Zn{sup 2+}. The crystal structure of the RPE was solved at 1.8 Angstroms resolution in the presence of D-xylitol 5-phosphate, an inert analogue of the D-xylulose 5-phosphate substrate. This structure suggests that the 2,3-enediolate intermediate in the 1,1-proton transfer reaction is stabilized by bidentate coordination to the Zn{sup 2+} that also is liganded to His 34, Asp 36, His 67, and Asp 176; the carboxylate groups of the Asp residues are positioned also to function as the acid/base catalysts. Although the conformation of the bound analogue resembles those of ligands bound in the active sites of OMPDC and KGPDC, the identities of the active site residues that coordinate the essential Zn{sup 2+} and participate as acid/base catalysts

  5. Phosphatidylinositol 5-phosphate 4-kinase type II beta is required for vitamin D receptor-dependent E-cadherin expression in SW480 cells

    Energy Technology Data Exchange (ETDEWEB)

    Kouchi, Zen, E-mail: zkouchi@toyaku.ac.jp [Laboratory of Genome and Biosignals, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji-city, Tokyo 192-0392 (Japan); Fujiwara, Yuki [Laboratory of Genome and Biosignals, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji-city, Tokyo 192-0392 (Japan); Yamaguchi, Hideki [Division of Metastasis and Invasion Signaling, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045 (Japan); PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi-city, Saitama 332-0012 (Japan); Nakamura, Yoshikazu; Fukami, Kiyoko [Laboratory of Genome and Biosignals, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji-city, Tokyo 192-0392 (Japan)

    2011-05-20

    Highlights: {yields} We analyzed Phosphatidylinositol 5-phosphate kinase II{beta} (PIPKII{beta}) function in cancer. {yields} PIPKII{beta} is required for vitamin D receptor-mediated E-cadherin upregulation in SW480. {yields} PIPKII{beta} suppresses cellular motility through E-cadherin induction in SW480 cells. {yields} Nuclear PIP{sub 2} but not plasma membrane-localized PIP{sub 2} mediates E-cadherin upregulation. -- Abstract: Numerous epidemiological data indicate that vitamin D receptor (VDR) signaling induced by its ligand or active metabolite 1{alpha},25-dihydroxyvitamin D{sub 3} (1{alpha},25(OH){sub 2}D{sub 3}) has anti-cancer activity in several colon cancers. 1{alpha},25(OH){sub 2}D{sub 3} induces the epithelial differentiation of SW480 colon cancer cells expressing VDR (SW480-ADH) by upregulating E-cadherin expression; however, its precise mechanism remains unknown. We found that phosphatidylinositol-5-phosphate 4-kinase type II beta (PIPKII{beta}) but not PIPKII{alpha} is required for VDR-mediated E-cadherin induction in SW480-ADH cells. The syntenin-2 postsynaptic density protein/disc large/zona occludens (PDZ) domain and pleckstrin homology domain of phospholipase C-delta1 (PLC{delta}1 PHD) possess high affinity for phosphatidylinositol-4,5-bisphosphate (PI(4,5)P{sub 2}) mainly localized to the nucleus and plasma membrane, respectively. The expression of syntenin-2 PDZ but not PLC{delta}1 PHD inhibited 1{alpha},25(OH){sub 2}D{sub 3}-induced E-cadherin upregulation, suggesting that nuclear PI(4,5)P{sub 2} production mediates E-cadherin expression through PIPKII{beta} in a VDR-dependent manner. PIPKII{beta} is also involved in the suppression of the cell motility induced by 1{alpha},25(OH){sub 2}D{sub 3}. These results indicate that PIPKII{beta}-mediated PI(4,5)P{sub 2} signaling is important for E-cadherin upregulation and inhibition of cellular motility induced by VDR activation.

  6. Purification, crystallization and X-ray crystallographic studies of a Bacillus cereus MepR-like transcription factor, BC0657.

    Science.gov (United States)

    Cho, Min Uk; Kim, Meong Il; Hong, Minsun

    2015-06-01

    Transcription factors of the MarR family respond to internal and external changes and regulate a variety of biological functions through ligand association with microorganisms. MepR belongs to the MarR family, and its mutations are associated with the development of multidrug resistance in Staphylococcus aureus, which has caused a growing health problem. In this study, a Bacillus cereus MepR-like transcription regulator, BC0657, was crystallized. The BC0657 crystals diffracted to 2.05 Å resolution and belonged to either space group P6(2)22 or P6(4)22, with unit-cell parameters a = 110.57, b = 110.57, c = 67.29 Å. There was one molecule per asymmetric unit. Future comparative structural studies on BC0657 would extend knowledge of ligand-induced transcriptional regulatory mechanisms in the MarR family and would make a significant contribution to the design of antibiotic drugs against multidrug-resistant bacteria.

  7. An insight into the sequential, structural and phylogenetic properties of banana 1-aminocyclopropane-1-carboxylate synthase 1 and study of its interaction with pyridoxal-5'-phosphate and aminoethoxyvinylglycine.

    Science.gov (United States)

    Choudhury, Swarup Roy; Singh, Sanjay Kumar; Roy, Sujit; Sengupta, Dibyendu N

    2010-06-01

    In banana, ethylene production for ripening is accompanied by a dramatic increase in 1-aminocyclopropane-1-carboxylate (ACC) content, transcript level of Musa acuminata ACC synthase 1 (MA-ACS1) and the enzymatic activity of ACC synthase 1 at the onset of the climacteric period. MA-ACS1 catalyses the conversion of S-adenosyl-L-methionine (SAM) to ACC, the key regulatory step in ethylene biosynthesis. Multiple sequence alignments of 1-aminocyclopropane-1-carboxylate synthase (ACS) amino acid sequences based on database searches have indicated that MA-ACS1 is a highly conserved protein across the plant kingdom. This report describes an in silico analysis to provide the first important insightful information about the sequential, structural and phylogenetic characteristics of MA-ACS1. The three-dimensional structure of MA-ACS1, constructed based on homology modelling, in combination with the available data enabled a comparative mechanistic analysis of MA-ACS1 to explain the catalytic roles of the conserved and non-conserved active site residues. We have further demonstrated that, as in apple and tomato, banana- ACS1 (MA-ACS1) forms a homodimer and a complex with cofactor pyridoxal-5'-phosphate (PLP) and inhibitor aminoethoxyvinylglycine (AVG). We have also predicted that the residues from the PLP-binding pocket, essential for ligand binding, are mostly conserved across the MA-ACS1 structure and the competitive inhibitor AVG binds at a location adjacent to PLP.

  8. Efficient production of a thermophilic 2-deoxyribose-5-phosphate aldolase in glucose-limited fed-batch cultivations of Escherichia coli by continuous lactose induction strategy.

    Science.gov (United States)

    Pei, Xiao-Lin; Wang, Qiu-Yan; Li, Cheng-Lu; Qiu, Xiao-Feng; Xie, Kai-Lin; Huang, Li-Feng; Wang, An-Ming; Zeng, Zhao-Wu; Xie, Tian

    2011-09-01

    The production of a thermophilic 2-deoxyribose-5-phosphate aldolases (DERA) in Escherichia coli BL21 under continuous lactose induction strategy was investigated. The process was combined with the exponential feeding method, controlling the feeding rate to maintain the specific growth rate at 0.15 h(-1). The results indicate that the lactose concentration in the feed medium affected directly the expression of the target protein. The use of 50 g/L in the feed medium resulted in the biomass concentration of 39.3 g DCW/L, and an expression level of above 30%, and the maximum final DERA concentration of 16,200 U/L. Furthermore, the acetate concentration remained at a low level in the fed-batch phase, less than 0.5 g/L. In conclusion, combining glucose feeding with lactose induction is a more powerful way to achieve high cell density cultures and to efficiently produce the thermophilic DERA. The results also indicate the potential industrial utility in the scale production of other recombinant proteins.

  9. [Reconstruction of muscle glycogen phosphorylase b from an apoenzyme and pyridoxal-5'-phosphate and its analogs. Interaction of apophosphorylase and the reconstructed enzyme with specific ligands].

    Science.gov (United States)

    Chebotareva, N A; Sugrobova, N P; Bulanova, L N; Poznanskaia, A A; Kurganov, B I; Gunar, V I

    1995-12-01

    Sedimentation methods were used to study the effects of modification of the pyridoxal-5'-phosphate (PLP) molecule at the 5th position on the affinity of reconstituted muscle glycogen phosphorylase b for the substrate (glycogen) and the allosteric inhibitor (FMN) as well as on the enzyme capacity to association induced by AMP. Reconstituted phosphorylase b was obtained with PLP analogs containing at the 5th position -CH2-CH2-COOH (analog I), trans-CH=CH-COOH (analog II) or -C identical to COOH (analog III) residues. Reconstitution of phosphorylase b is accompanied by the recovery of the enzyme quaternary structure. Phosphorylase b reconstituted with PLP or analogs I, II and III is not distinguished practically from the native enzyme in its affinity for glycogen. Substitution of the native coenzyme in the phosphorylase molecule with any tested PLP analog leads to lower enzyme affinity for FMN. Microscopic dissociation constants of the FMN-enzyme complexes increase in the following order: enzyme.I < enzyme.II < enzyme.III. Phosphorylase b reconstituted with analogs I, II and III differs substantially from the native enzyme in its capacity to association in the presence of 1 mM AMP: the reconstituted enzyme is represented practically by only the tetrameric form.

  10. Formation of Schiff bases of O-phosphorylethanolamine and O-phospho-D,L-serine with pyridoxal 5'-phosphate. experimental and theoretical studies.

    Science.gov (United States)

    Vilanova, Bartolomé; Gallardo, Jessica M; Caldés, Catalina; Adrover, Miquel; Ortega-Castro, Joaquín; Muñoz, Francisco; Donoso, Josefa

    2012-03-01

    Pyridoxal 5'-phosphate (PLP) is a B(6) vitamer acting as an enzyme cofactor in various reactions of aminoacid metabolism and inhibiting glycation of biomolecules. Nonenzymatic glycation of aminophospholipids alters the stability of lipid bilayers and cell function as a result. Similarly to protein glycation, aminophospholipid glycation initially involves the formation of a Schiff base. In this work, we studied the formation of Schiff bases between PLP and two compounds mimicking the polar head of natural aminophospholipids, namely: O-phosphorylethanolamine and O-phospho-D,L-serine. Based on the results, the pH-dependence of the microscopic constants of the two PLP-aminophosphate systems studied is identical with that for PLP-aminoacid systems. However, the rate and equilibrium formation constants for the Schiff bases of the aminophosphates are low relative to those for the aminoacids. A theoretical study by density functional theory of the formation mechanism for the Schiff bases of PLP with the two aminophospholipid analogues confirmed that the activation energy of formation of the Schiff bases is greater with aminophosphates; on the other hand, that of hydrolysis is essentially similar with aminoacids and aminophosphates.

  11. Structure-Based Optimization of Pyridoxal 5'-Phosphate-Dependent Transaminase Enzyme (BioA) Inhibitors that Target Biotin Biosynthesis in Mycobacterium tuberculosis.

    Science.gov (United States)

    Liu, Feng; Dawadi, Surendra; Maize, Kimberly M; Dai, Ran; Park, Sae Woong; Schnappinger, Dirk; Finzel, Barry C; Aldrich, Courtney C

    2017-07-13

    The pyridoxal 5'-phosphate (PLP)-dependent transaminase BioA catalyzes the second step in the biosynthesis of biotin in Mycobacterium tuberculosis (Mtb) and is an essential enzyme for bacterial survival and persistence in vivo. A promising BioA inhibitor 6 containing an N-aryl, N'-benzoylpiperazine scaffold was previously identified by target-based whole-cell screening. Here, we explore the structure-activity relationships (SAR) through the design, synthesis, and biological evaluation of a systematic series of analogues of the original hit using a structure-based drug design strategy, which was enabled by cocrystallization of several analogues with BioA. To confirm target engagement and discern analogues with off-target activity, each compound was evaluated against wild-type (WT) Mtb in biotin-free and -containing medium as well as BioA under- and overexpressing Mtb strains. Conformationally constrained derivative 36 emerged as the most potent analogue with a KD of 76 nM against BioA and a minimum inhibitory concentration of 1.7 μM (0.6 μg/mL) against Mtb in biotin-free medium.

  12. Properties of immobilized flavodoxin from Peptostreptococcus elsdenii. An affinity ligand for the purification of riboflavin 5'-phosphate (FMN) and its analogues.

    Science.gov (United States)

    Mayhew, S G; Strating, M J

    1975-11-15

    The small flavoprotein, flavodoxin, isolated from Peptostreptococcus elsdenii, has been covalently coupled to CNBr-activated Sepharose 4B. The immobilized protein replaces ferredoxin as an electron carrier in hydrogen production from dithionite or pyruvate in the presence of ferredoxin-free extracts of P. elsdenii; compared with soluble flavodoxin, its activities in these systems are 13% and 3.5% respectively. Acid treatment reversibly dissociates FMN from the immobilized protein. The dissociation constant of the complex with FMN, determined by fluorimetric titration, is 1.5 (+/- 0.4) nM, and is therefore very little different from that of soluble flavodoxin. Like soluble apoflavodoxin, the immobilized apoprotein is highly specific for flavins with an N-10 side-chain of 5 carbon atoms and a C-5' phosphate group. Approximately half of the flavin impurity in commercial preparations of FMN (12-15% of the total flavin), and similar impurity in synthetic analogues of FMN, is not separated by conventional purification procedures, but it is readily and conveniently removed by affinity chromatography with apoflavodoxin as the immobilized ligand. The immobilized protein is stable for long periods; its capacity for FMN decreases by only 20% after 15 cycles of flavin dissociation and reassociation during several months.

  13. Influence of pyridoxal 5'-phosphate alone and in combination with vigabatrin on brain GABA measured by 1H-NMR-spectroscopy.

    Science.gov (United States)

    Mueller, S G; Weber, O M; Boesiger, P; Wieser, H G

    2001-07-01

    Both iso-forms of the gamma-aminobutyric acid (GABA) synthesising enzyme and also the GABA degrading enzyme need pyridoxal 5'-phosphate (PP) as co-enzyme. The aim of the study was to investigate the influence of PP alone and in combination with various doses of vigabatrin (VGB) on brain GABA levels. In eight healthy subjects 300 mg/d PP and various doses of VGB (range, 1000 mg/d to 4000 mg/d) were given alone or in combination. The GABA+/creatine (Cr) signals in both occipital lobes were measured before treatment, during monotherapy with PP or VGB, and during combination of both using 1H-NMR-spectroscopy (1H-NMRS). PP alone did not change the GABA+/Cr signals. VGB alone increased the GABA+/Cr signals in both hemispheres. The combination PP and low-medium dosed VGB (1000-2000 mg/d) did not increase the GABA+/Cr signals. The effects of the combination of PP and high dosed (3000-4000 mg/d) VGB on the GABA+/Cr signals varied depending on the sequence of the drugs and dose of VGB. PP alone has no effect on the GABA+/Cr signals in healthy volunteers. The combination of PP and low-high dosed VGB had inconsistent effects on the GABA+/Cr signals compared to a VGB monotherapy because PP activates also the GABA-degrading enzyme GABA-transaminase.

  14. Method for Assaying the Lipid Kinase Phosphatidylinositol-5-phosphate 4-kinase α in Quantitative High-Throughput Screening (qHTS) Bioluminescent Format

    Science.gov (United States)

    Davis, Mindy I.; Sasaki, Atsuo T.; Simeonov, Anton

    2015-01-01

    Summary ipid kinases are important regulators of a variety of cellular processes and their dysregulation causes diseases such as cancer and metabolic diseases. Distinct lipid kinases regulate the seven different phosphorylated forms of phosphatidylinositol (PtdIns). Some lipid kinases utilize long-chain lipid substrates that have limited solubility in aqueous solutions, which can lead to difficulties in developing a robust and miniaturizable biochemical assay. The ability to prepare the lipid substrate and develop assays to identify modulators of lipid kinases is important and is the focus of this methods chapter. Herein, we describe a method to prepare a DMSO-based lipid mixture that enables the 1536-well screening of the lipid kinase phosphatidylinositol-5-phosphate 4-kinase α (PI5P4Kα) utilizing the D-myo-di16-PtIns(5)P substrate in quantitative high-throughput screening (qHTS) format using the ADP-Glo™ technology to couple the production of ADP to a bioluminescent readout. PMID:26552670

  15. Quantum mechanics/molecular mechanics studies on the mechanism of action of cofactor pyridoxal 5'-phosphate in ornithine 4,5-aminomutase.

    Science.gov (United States)

    Pang, Jiayun; Scrutton, Nigel S; Sutcliffe, Michael J

    2014-09-01

    A computational study was performed on the experimentally elusive cyclisation step in the cofactor pyridoxal 5'-phosphate (PLP)-dependent D-ornithine 4,5-aminomutase (OAM)-catalysed reaction. Calculations using both model systems and a combined quantum mechanics/molecular mechanics approach suggest that regulation of the cyclic radical intermediate is achieved through the synergy of the intrinsic catalytic power of cofactor PLP and the active site of the enzyme. The captodative effect of PLP is balanced by an enzyme active site that controls the deprotonation of both the pyridine nitrogen atom (N1) and the Schiff-base nitrogen atom (N2). Furthermore, electrostatic interactions between the terminal carboxylate and amino groups of the substrate and Arg297 and Glu81 impose substantial "strain" energy on the orientation of the cyclic intermediate to control its trajectory. In addition the "strain" energy, which appears to be sensitive to both the number of carbon atoms in the substrate/analogue and the position of the radical intermediates, may play a key role in controlling the transition of the enzyme from the closed to the open state. Our results provide new insights into several aspects of the radical mechanism in aminomutase catalysis and broaden our understanding of cofactor PLP-dependent reactions.

  16. Reaction mechanism of Zn2+-dependent d-serine dehydratase: role of a conserved tyrosine residue interacting with pyridine ring nitrogen of pyridoxal 5'-phosphate.

    Science.gov (United States)

    Ito, Tomokazu; Matsuoka, Mai; Koga, Kazushi; Hemmi, Hisashi; Yoshimura, Tohru

    2014-09-01

    d-Serine dehydratase from Saccharomyces cerevisiae (Dsd1p) is a pyridoxal 5'-phosphate (PLP)- and Zn(2+)-dependent enzyme that catalyzes the dehydration of d-serine to yield pyruvate and ammonia. Dsd1p uses the Tyr residue (Y203) to interact with the pyridine nitrogen of PLP, which is a unique feature of PLP enzymes. To investigate the role of Y203 in catalysis, a series of Y203 mutants was constructed and studied. Mutant enzymes possessing a non-polar or a basic residue instead of Y203 (Y203F, A, S and R) exhibited substantial levels of catalytic activity, and among these, the Y203F mutant had the least impact on catalytic activity. The Y203D exhibited a 10(5)-fold decrease in enzyme activity, and unlike wild-type enzyme, the mutant enzyme favoured the Cα reprotonation before hydroxyl group protonation. Our data show that the Y203 does not participate in the protonation of the pyridine nitrogen (N1) of PLP, and Dsd1p uses the cofactor in an N1-unprotonated state. The unprotonated N1 promotes elimination of the leaving group and evades Cα reprotonation before hydroxyl group protonation.

  17. Mutations in Escherichia coli aceE and ribB genes allow survival of strains defective in the first step of the isoprenoid biosynthesis pathway.

    Directory of Open Access Journals (Sweden)

    Jordi Perez-Gil

    Full Text Available A functional 2-C-methyl-D-erythritol 4-phosphate (MEP pathway is required for isoprenoid biosynthesis and hence survival in Escherichia coli and most other bacteria. In the first two steps of the pathway, MEP is produced from the central metabolic intermediates pyruvate and glyceraldehyde 3-phosphate via 1-deoxy-D-xylulose 5-phosphate (DXP by the activity of the enzymes DXP synthase (DXS and DXP reductoisomerase (DXR. Because the MEP pathway is absent from humans, it was proposed as a promising new target to develop new antibiotics. However, the lethal phenotype caused by the deletion of DXS or DXR was found to be suppressed with a relatively high efficiency by unidentified mutations. Here we report that several mutations in the unrelated genes aceE and ribB rescue growth of DXS-defective mutants because the encoded enzymes allowed the production of sufficient DXP in vivo. Together, this work unveils the diversity of mechanisms that can evolve in bacteria to circumvent a blockage of the first step of the MEP pathway.

  18. Mutations in Escherichia coli aceE and ribB genes allow survival of strains defective in the first step of the isoprenoid biosynthesis pathway.

    Science.gov (United States)

    Perez-Gil, Jordi; Uros, Eva Maria; Sauret-Güeto, Susanna; Lois, L Maria; Kirby, James; Nishimoto, Minobu; Baidoo, Edward E K; Keasling, Jay D; Boronat, Albert; Rodriguez-Concepcion, Manuel

    2012-01-01

    A functional 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway is required for isoprenoid biosynthesis and hence survival in Escherichia coli and most other bacteria. In the first two steps of the pathway, MEP is produced from the central metabolic intermediates pyruvate and glyceraldehyde 3-phosphate via 1-deoxy-D-xylulose 5-phosphate (DXP) by the activity of the enzymes DXP synthase (DXS) and DXP reductoisomerase (DXR). Because the MEP pathway is absent from humans, it was proposed as a promising new target to develop new antibiotics. However, the lethal phenotype caused by the deletion of DXS or DXR was found to be suppressed with a relatively high efficiency by unidentified mutations. Here we report that several mutations in the unrelated genes aceE and ribB rescue growth of DXS-defective mutants because the encoded enzymes allowed the production of sufficient DXP in vivo. Together, this work unveils the diversity of mechanisms that can evolve in bacteria to circumvent a blockage of the first step of the MEP pathway.

  19. Study of the factors affecting the performance of microextraction by packed sorbent (MEPS) using liquid scintillation counter and liquid chromatography-tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Altun, Zeki [Karlstad University, Faculty of Technology and Science, SE-651 88 Karlstad (Sweden); Abdel-Rehim, Mohamed [Karlstad University, Faculty of Technology and Science, SE-651 88 Karlstad (Sweden); Clinical Pharmacology and DMPK, AstraZeneca R and D Soedertaelje, SE-151 85 Soedertaelje (Sweden)], E-mail: Mohamed.Abdel-Rehim@Astrazeneca.com

    2008-12-23

    Microextraction by packed sorbent (MEPS) is a new technique for sample preparation that can be connected on-line with LC or GC. In MEPS, approximately 1-2 mg of the solid packing material is inserted into a syringe (100-250 {mu}L) as a plug. Sample preparation takes place on the packed bed. The bed can be packed or coated to provide selective and suitable sampling conditions. The new method is very promising for extraction of drugs and metabolites from biological samples. In this paper, some factors affecting the performance of MEPS such as recovery, carry-over, leakage, washing volume and elution volume were studied using C18 and hydroxylated polystyrene-divinylbenzene copolymer (ENV+) as sorbents. Radioactively labelled bupivacaine in plasma samples was used as test analyte. For the extraction of this drug, using methanol/water 95:5 (v/v) (0.25% ammonium hydroxide) was used as elution solvent. The analyte response increased with increasing the elution volume and it was linear upp up to 100 {mu}L utilizing liquid scintillation counter. Further, for concentrating the sample, we found that MEPS may be used such that the sample can be drawn through the needle, up and down, several times. The analyte leakage increases as the volume washing increases, though higher washing volumes may also result in cleaner extracts. To eliminate analyte carry-over, the sorbents were washed first with 3 x 250 {mu}L elution solution and then with 3 x 250 {mu}L washing solution. In addition, the reproducibility measurements show relatively good relative standard deviation (RSD) % values concerning analyte recovery and analyte leakage. The present study provides an understanding of basic aspects when optimizing methods for MEPS. In this study, MEPS was used off-line with liquid scintillation counter and on-line with LC-MS/MS.

  20. 2-substituted derivatives of adenosine and inosine cyclic 3',5'-phosphate. Synthesis, enzymic activity, and analysis of the structural requirements of the binding locale of the 2-substituent on bovine brain protein kinase.

    Science.gov (United States)

    Meyer, R B; Uno, H; Robins, R K; Simon, L N; Miller, J P

    1975-07-29

    A number of 2-substituted cyclic nucleotide derivatives were synthesized and investigated as activators of cAMP-dependent protein kinase and as substrates for and inhibitors of cAMP phosphodiesterase. Ring closure of 5-amino-1-beta-D-ribofuranosylimidazol-4-carboxamide cyclic 3',5'-phosphate (1) with various aldehydes according to a new procedure (Meyer, R. B., Jr., Shuman, D.A., and Robins, R. K. (1974), J. Am. Chem. Soc. 96, 4962) gave new derivatives of adenosine cyclic 3',5'-phosphate with the following 2-substituents: n-propyl, n-hexl, n-octyl, n-decyl, styryl, o-methoxyphenyl, and 2-thienyl. Alkylation of 2-mercaptoadenosine cyclic 3',5'-phosphate (20, Meyer et al., 1974) gave new cAMP derivatives with the following 2-substituent: ethylthio, n-propylthio, isopropylthio, allylthio, n-decylthio, and benzylthio. Deamination of 2-methyl-,2-n-butyl-, and 2-ethylthioadenosine cyclic 3',5'-phosphate. Using multiple regression analysis, a striking relationship was found between the relative potency of the compounds as activators of bovine brain cAMP-dependent protein kinase and parameters describing the hydrophobic, steric, and electronic character of the substituents on these compounds. All compounds were substrates for a cyclic nucleotide phosphodiesterase preparation from rabbit kidney. Additionally, the compounds were as a group, good inhibitors of the hydrolysis of cAMP by phosphodiesterase preparations from rabbit lung, beef heart, and dog heart.

  1. Properties and inhibition of the first two enzymes of the non-mevalonate pathway of isoprenoid biosynthesis.

    Science.gov (United States)

    Mueller, C; Schwender, J; Zeidler, J; Lichtenthaler, H K

    2000-12-01

    Enzymes of the 1-deoxy-D-xylulose 5-phosphate/2-C-methylerythritol 4-phosphate (DOXP/MEP) pathway are targets for new herbicides and antibacterial drugs. Until now, no inhibitors for the DOXP synthase have been known of. We show that one of the breakdown products of the herbicide clomazone affects the DOXP synthase. One inhibitor of the non-mevalonate pathway, fosmidomycin, blocks the DOXP reductoisomerase (DXR) of plants and bacteria. The I(50) values of plants are, however, higher than those found for the DXR of Escherichia coli. The DXR of plants, isolated from barley seedlings, shows a pH optimum of 8.1, which is typical for enzymes active in the chloroplast stroma.

  2. Structure of L-Xylulose-5-Phosphate 3-Epimerase (UlaE) from the Anaerobic L-Ascorbate Utilization Pathway of Escherichia coli: Identification of a Novel Phosphate Binding Motif within a TIM Barrel Fold

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Rong; Pineda, Marco; Ajamian, Eunice; Cui, Qizhi; Matte, Allan; Cygler, Miroslaw (McGill); (NRC-Canada)

    2009-01-15

    Three catabolic enzymes, UlaD, UlaE, and UlaF, are involved in a pathway leading to fermentation of L-ascorbate under anaerobic conditions. UlaD catalyzes a {beta}-keto acid decarboxylation reaction to produce L-xylulose-5-phosphate, which undergoes successive epimerization reactions with UlaE (L-xylulose-5-phosphate 3-epimerase) and UlaF (L-ribulose-5-phosphate 4-epimerase), yielding D-xylulose-5-phosphate, an intermediate in the pentose phosphate pathway. We describe here crystallographic studies of UlaE from Escherichia coli O157:H7 that complete the structural characterization of this pathway. UlaE has a triosephosphate isomerase (TIM) barrel fold and forms dimers. The active site is located at the C-terminal ends of the parallel {beta}-strands. The enzyme binds Zn{sup 2+}, which is coordinated by Glu155, Asp185, His211, and Glu251. We identified a phosphate-binding site formed by residues from the {beta}1/{alpha}1 loop and {alpha}3' helix in the N-terminal region. This site differs from the well-characterized phosphate-binding motif found in several TIM barrel superfamilies that is located at strands {beta}7 and {beta}8. The intrinsic flexibility of the active site region is reflected by two different conformations of loops forming part of the substrate-binding site. Based on computational docking of the L-xylulose 5-phosphate substrate to UlaE and structural similarities of the active site of this enzyme to the active sites of other epimerases, a metal-dependent epimerization mechanism for UlaE is proposed, and Glu155 and Glu251 are implicated as catalytic residues. Mutation and activity measurements for structurally equivalent residues in related epimerases supported this mechanistic proposal.

  3. Comparative studies on the properties of tryptophanase and tyrosine phenol-lyase immobilized directly on Sepharose or by use of Sepharose-bound pyridoxal 5'-phosphate.

    Science.gov (United States)

    Fukui, S; Ikeda, S; Fujimura, M; Yamada, H; Kumagai, H

    1975-02-01

    Tryptophanase from Escherichia coli B/qt 7-A and tyrosine phenol-lyase (beta-tyrosinase) from Escherichia intermedia were immobilized on Sepharose 4B by several direct coupling reactions or through pyridoxal 5'-phosphate previously bound to Sepharose. The most active preparation of immobilized tryptophanase was obtained by coupling tetrameric apoenzyme to pyridoxal-P bound on Sepharose at the 6-position through a diazo linkage. This immobilization procedure involves the formation to Schiff base linkage between 4-formyl group of Sepharose-bound pyridoxal-P and the epsilon-amino group of the lysine residue at the active center of one subunit of tetrameric apo-tryptophanase, followed by the fixation of the Schiff base linkage by reduction with NaBH4. In the case of beta-tyrosinase having two catalytic centers, however, this method was not so suitable as the case of tryptophanase. Direct coupling of the apoenzyme to CNBr-activated Sepharose or to a bromoacetyl derivative of Sepharose gave better results. In each case, the affinity for substrate or coenzyme was scarcely influenced by the immobilization. When used repeatedly in a batch system or continuously in a flow system in the absence of added pyridoxal-P, immobilized holo-tryptophanase of holo-beta-tyrosinase gradually lost its original activity; however, supplement of pyridoxal-P to the reaction system restored its initial activity. From the kinetic analyses of these phenomena, the rate constants of coenzyme dissociation from immobilized tryptophanase and beta-tyrosinase were calculated. Upon immobilization, the pH optima of both enzymes shifted 0.5 to 1.0 pH unit to the alkaline side. Both immobilized enzymes showed higher thermal stability and resistance to a denaturing agent such as guinidine-HCl than their free counterpart. Furthermore, the reactivity of sulfhydryl group of beta-tyrosinase, in connection with its coenzyme-binding property, was conveniently studied by use of the immobilized enzyme.

  4. Systems-Wide Prediction of Enzyme Promiscuity Reveals a New Underground Alternative Route for Pyridoxal 5'-Phosphate Production in E. coli.

    Directory of Open Access Journals (Sweden)

    Matthew A Oberhardt

    2016-01-01

    Full Text Available Recent insights suggest that non-specific and/or promiscuous enzymes are common and active across life. Understanding the role of such enzymes is an important open question in biology. Here we develop a genome-wide method, PROPER, that uses a permissive PSI-BLAST approach to predict promiscuous activities of metabolic genes. Enzyme promiscuity is typically studied experimentally using multicopy suppression, in which over-expression of a promiscuous 'replacer' gene rescues lethality caused by inactivation of a 'target' gene. We use PROPER to predict multicopy suppression in Escherichia coli, achieving highly significant overlap with published cases (hypergeometric p = 4.4e-13. We then validate three novel predicted target-replacer gene pairs in new multicopy suppression experiments. We next go beyond PROPER and develop a network-based approach, GEM-PROPER, that integrates PROPER with genome-scale metabolic modeling to predict promiscuous replacements via alternative metabolic pathways. GEM-PROPER predicts a new indirect replacer (thiG for an essential enzyme (pdxB in production of pyridoxal 5'-phosphate (the active form of Vitamin B6, which we validate experimentally via multicopy suppression. We perform a structural analysis of thiG to determine its potential promiscuous active site, which we validate experimentally by inactivating the pertaining residues and showing a loss of replacer activity. Thus, this study is a successful example where a computational investigation leads to a network-based identification of an indirect promiscuous replacement of a key metabolic enzyme, which would have been extremely difficult to identify directly.

  5. Bimetallic magnetic nanoparticle as a new platform for fabrication of pyridoxine and pyridoxal-5'-phosphate imprinted polymer modified high throughput electrochemical sensor.

    Science.gov (United States)

    Patra, Santanu; Roy, Ekta; Das, Ranajit; Karfa, Paramita; Kumar, Sunil; Madhuri, Rashmi; Sharma, Prashant K

    2015-11-15

    The present work describes the fabrication of a selective and sensitive molecularly imprinted polymer (MIP)-based electrochemical sensor using a combination of surface imprinting and nanotechnology. The fabricated sensor was used for the detection of two major components of vitamin B6 i.e. pyridoxine (Py) and pyridoxal-5'-phosphate (PLP) using the same MIP format. Herein, acrylic acid modified zero valent iron nanoparticles were combined with the copper nanoparticle, resulting in vinyl groups modified bimetallic Fe/Cu magnetic nanoparticles (BMNPs). These BMNPs have high surface to volume ratios, higher electro-catalytic activity, and are therefore, a suitable platform to synthesize specific MIP cavities for Py and PLP. Herein, two different MIP formats (for Py and PLP) were synthesized on the surface of vinyl silane modified pencil graphite electrodes by activator regenerated by an electron transfer-atom transfer radical polymerization (ARGET-ATRP) method. The sensor shows a good analytical performance for the detection of Py and PLP by a square wave stripping voltammetric technique (SWSV). The limit of detection (LOD) was calculated to be 0.040 µg L(-1) and 0.043 µg L(-1) for Py and PLP, respectively, at signal to noise ratio of 3. The sensors are highly selective for the templates and can detect them from multivitamin tablets, corn flakes, energy drinks, cerebrospinal fluid (CSF) and blood samples (serum, plasma and whole blood) without any interfering effect, suggesting the clinical applicability of the fabricated sensor. The sensor can also be used as better alternative to the commercially available ELISA kits which are rather complex, less sensitive and difficult to handle.

  6. Development of inhibitors of the 2C-methyl-D-erythritol 4-phosphate (MEP) pathway enzymes as potential anti-infective agents

    NARCIS (Netherlands)

    Masini, Tiziana; Hirsch, Anna K H

    2014-01-01

    Important pathogens such as Mycobacterium tuberculosis and Plasmodium falciparum, the causative agents of tuberculosis and malaria, respectively, and plants, utilize the 2C-methyl-D-erythritol 4-phosphate (MEP, 5) pathway for the biosynthesis of isopentenyl diphosphate (1) and dimethylallyl

  7. Novel bioassay for the discovery of inhibitors of the 2-C-methyl-D-erythritol 4-phosphate (MEP and terpenoid pathways leading to carotenoid biosynthesis.

    Directory of Open Access Journals (Sweden)

    Natália Corniani

    Full Text Available The 2-C-methyl-D-erythritol 4-phosphate (MEP pathway leads to the synthesis of isopentenyl diphosphate in plastids. It is a major branch point providing precursors for the synthesis of carotenoids, tocopherols, plastoquinone and the phytyl chain of chlorophylls, as well as the hormones abscisic acid and gibberellins. Consequently, disruption of this pathway is harmful to plants. We developed an in vivo bioassay that can measure the carbon flow through the carotenoid pathway. Leaf cuttings are incubated in the presence of a phytoene desaturase inhibitor to induce phytoene accumulation. Any compound reducing the level of phytoene accumulation is likely to interfere with either one of the steps in the MEP pathway or the synthesis of geranylgeranyl diphosphate. This concept was tested with known inhibitors of steps of the MEP pathway. The specificity of this in vivo bioassay was also verified by testing representative herbicides known to target processes outside of the MEP and carotenoid pathways. This assay enables the rapid screen of new inhibitors of enzymes preceding the synthesis of phytoene, though there are some limitations related to the non-specific effect of some inhibitors on this assay.

  8. Novel bioassay for the discovery of inhibitors of the 2-C-Methyl-D-Erythritol 4-Phosphate (MEP) and terpenoid pathways leading to carotenoid biosynthesis

    Science.gov (United States)

    The 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway leads to the synthesis of isopentenyl-phosphate (IPP) in plastids. It is a major branch point providing precursors for the synthesis of carotenoids, tocopherols, plastoquinone and the phytyl chain of chlorophylls, as well as the hormones abscisi...

  9. Molecular evolution of B6 enzymes: Binding of pyridoxal-5'-phosphate and Lys41Arg substitution turn ribonuclease A into a model B6 protoenzyme

    Directory of Open Access Journals (Sweden)

    Marra Ersilia

    2008-06-01

    Full Text Available Abstract Background The pyridoxal-5'-phosphate (PLP-dependent or vitamin B6-dependent enzymes that catalyze manifold reactions in the metabolism of amino acids belong to no fewer than four evolutionarily independent protein families. The multiple evolutionary origin and the essential mechanistic role of PLP in these enzymes argue for the cofactor having arrived on the evolutionary scene before the emergence of the respective apoenzymes and having played a dominant role in the molecular evolution of the B6 enzyme families. Here we report on an attempt to re-enact the emergence of a PLP-dependent protoenzyme. The starting protein was pancreatic ribonuclease A (RNase, in which active-site Lys41 or Lys7 readily form a covalent adduct with PLP. Results We screened the PLP adduct of wild-type RNase and two variant RNases (K7R and K41R for catalytic effects toward L- and D-amino acids. RNase(K41R-PLP, in which the cofactor is bound through an imine linkage to Lys7, qualifies for a model proto-B6 enzyme by the following criteria: (1 covalent linkage of PLP (internal aldimine; (2 catalytic activity toward amino acids that depends on formation of an imine linkage with the substrate (external aldimine; (3 adjoining binding sites for the cofactor and amino acid moiety that facilitate the transimination reaction of the internal to the external aldimine and stabilize the resulting noncovalent complex of the coenzyme-substrate adduct with the protein; (4 reaction specificity, the only detectable reactions being racemization of diverse amino acids and β-decarboxylation of L-aspartate; (5 acceleration factors for racemization and β-decarboxylation of >103 over and above that of PLP alone; (6 ribonuclease activity that is 103-fold lower than that of wild-type RNase, attenuation of a pre-existing biological activity being indispensable for the further evolution as a PLP-dependent protoenzyme. Conclusion A single amino acid substitution (Lys41Arg and covalent

  10. Spectroscopic investigation, vibrational assignments, HOMO-LUMO, NBO, MEP analysis and molecular docking studies of oxoaporphine alkaloid liriodenine

    Science.gov (United States)

    Costa, Renyer A.; Pitt, Priscilla Olliveira; Pinheiro, Maria Lucia B.; Oliveira, Kelson M. T.; Salomé, Kahlil Schwanka; Barison, Andersson; Costa, Emmanoel Vilaça

    2017-03-01

    A combined experimental and theoretical DFT study of the structural, vibrational and electronic properties of liriodenine is presented using B3LYP function with 6-311G (2d, p) basis set. The theoretical geometry optimization data were compared with the X-ray data for a similar structure in the associated literature, showing similar values. In addition, natural bond orbitals (NBOs), HOMO-LUMO energy gap, mapped molecular Electrostatic Potential (MEP) surface calculation, first and second order hyperpolarizabilities were also performed with the same calculation level. Theoretical UV spectrum agreed well with the measured experimental data, with transitions assigned. The molecular electrostatic potential map shows opposite potentials regions that forms hydrogen bonds that stabilize the dimeric form, which were confirmed by the close values related to the C dbnd O bond stretching between the dimeric form and the experimental IR spectra (1654 cm- 1 for the experimental, 1700 cm- 1 for the dimer form). Calculated HOMO/LUMO gaps shows the excitation energy for Liriodenine, justifying its stability and kinetics reaction. Molecular docking studies with Candida albicans dihydrofolate reductase (DHFR) and Candida albicans secreted aspartic protease (SAP) showed binding free energies values of - 8.5 and - 8.3 kcal/mol, suggesting good affinity between the liriodenine and the target macromolecules.

  11. Map-Based Cloning of zb7 Encoding an IPP and DMAPP Synthase in the MEP Pathway of Maize

    Institute of Scientific and Technical Information of China (English)

    Xiao-Min Lu; Jin-Sheng Lai; Xiao-Jiao Hu; Yuan-Zeng Zhao; Wei-Bin Song; Mei Zhang; Zong-Liang Chen; Wei Chen; Yong-Bin Dong; Zhen-Hua Wang

    2012-01-01

    IspH is a key enzyme in the last step of the methyI-D-erythritol-4-phosphate (MEP) pathway.Loss of function of IspH can often result in complete yellow or albino phenotype in many plants.Here,we report the characterization of a recessive mutant of maize,zebra7 (zb7),showing transverse green/yellow striped leaves in young plants.The yellow bands of the mutant have decreased levels of chlorophylls and carotenoids with delayed chloroplast development.Low temperature suppressed mutant phenotype,while alternate light/dark cycle or high temperature enlarged the yellow section.Map-based cloning demonstrated that zb7 encodes the IspH protein with a mis-sense mutation in a conserved region.Transgenic silencing of Zb7 in maize resulted in complete albino plantlets that are aborted in a few weeks,confirming that Zb7 is important in the early stages of maize chloroplast development.Zb7 is constitutively expressed and its expression subject to a 16-h light/8-h dark cycle regulation.Our results suggest that the less effective or unstable IspH in zb7 mutant,together with its diurnal expression,are mechanistically accounted for the zebra phenotype.The increased IspH mRNA in the leaves of zb7 at the late development stage may explain the restoration of mutant phenotype in mature stages.

  12. Elicitor induced activation of the methylerythritol phosphate pathway toward phytoalexins biosynthesis in rice.

    Science.gov (United States)

    Okada, Atsushi; Shimizu, Takafumi; Okada, Kazunori; Kuzuyama, Tomohisa; Koga, Jinichiro; Shibuya, Naoto; Nojiri, Hideaki; Yamane, Hisakazu

    2007-09-01

    Diterpenoid phytoalexins such as momilactones and phytocassanes are produced via geranylgeranyl diphosphate in suspension-cultured rice cells after treatment with a chitin elicitor. We have previously shown that the production of diterpene hydrocarbons leading to phytoalexins and the expression of related biosynthetic genes are activated in suspension-cultured rice cells upon elicitor treatment. To better understand the elicitor-induced activation of phytoalexin biosynthesis, we conducted microarray analysis using suspension-cultured rice cells collected at various times after treatment with chitin elicitor. Hierarchical cluster analysis revealed two types of early-induced expression (EIE-1, EIE-2) nodes and a late-induced expression (LIE) node that includes genes involved in phytoalexins biosynthesis. The LIE node contains genes that may be responsible for the methylerythritol phosphate (MEP) pathway, a plastidic biosynthetic pathway for isopentenyl diphosphate, an early precursor of phytoalexins. The elicitor-induced expression of these putative MEP pathway genes was confirmed by quantitative reverse-transcription PCR. 1-Deoxy-D: -xylulose 5-phosphate synthase (DXS), 1-deoxy-D: -xylulose 5-phosphate reductoisomerase (DXR), and 4-(cytidine 5'-diphospho)-2-C-methyl-D: -erythritol synthase (CMS), which catalyze the first three committed steps in the MEP pathway, were further shown to have enzymatic activities that complement the growth of E. coli mutants disrupted in the corresponding genes. Application of ketoclomazone and fosmidomycin, inhibitors of DXS and DXR, respectively, repressed the accumulation of diterpene-type phytoalexins in suspension cells treated with chitin elicitor. These results suggest that activation of the MEP pathway is required to supply sufficient terpenoid precursors for the production of phytoalexins in infected rice plants.

  13. 变异链球菌核糖-5-磷酸异构酶A的表达、纯化与鉴定%Expression, purification and characterization of ribose 5-phosphate isomerase A from Streptococcus mutans

    Institute of Scientific and Technical Information of China (English)

    武文琦; 丛旭珍; 殷爱红; 胡家; 翟方丽; 李慎涛

    2012-01-01

    目的 在大肠杆菌中高效表达变异链球菌核糖-5-磷酸异构酶A( ribose 5-phosphate isomerase A,rpiA ),并对表达产物进行纯化和鉴定.方法 根据GenBank中变异链球菌UA159株基因组rpiA的DNA编码序列,设计PCR引物,扩增变异链球菌核糖-5-磷酸异构酶A的DNA编码序列,将其克隆至pGEX-6p-1载体中,构建重组质粒,将测序正确的重组质粒转化入大肠杆菌BL21 (DE3)中,用异丙基-β-D-硫代吡喃半乳糖苷(isopropyl β-D-1-thiogalactopyranoside,IPTG)诱导表达;对培养温度、IPTG用量、诱导时间等条件进行了优化;用亲和层析、离子交换层析纯化目标蛋白;用SDS-PAGE和质谱对目标蛋白进行鉴定.结果 变异链球菌核糖-5-磷酸异构酶A在大肠杆菌中高效、可溶性表达,经质谱鉴定及SDS-PAGE分析,表达产物为变异链球菌核糖-5-磷酸异构酶A蛋白.经过纯化,得到纯度高达95%的变异链球菌核糖-5-磷酸异构酶A.结论 成功地在大肠杆菌中高效表达了变异链球菌核糖-5-磷酸异构酶A蛋白,并建立了纯化工艺,得到高纯度的重组蛋白,为进一步研究变异链球菌属核糖-5-磷酸异构酶蛋白的生物学活性及功能奠定了基础.%Objective To express, purify and characterize the ribose 5-phosphate isomerase A(rpiA) from Streptococcus muians. Methods A DNA fragment encoding S. mutans ribose 5-phosphate isomerase A was amplified by PCR using the genomic DNA of Streptococcus mutans UA159 as a template. The PCR product was cloned into vector pGEX-6p-l. The construct carrying the coding DNA sequence of rpiA fused with GST was transformed into E. coli BL21 (DE3) , and the fusion protein was expressed by induction with IPTG. The recombinant protein was purified by affinity chromatography and ion exchange chromatography. The purified target protein was identified by SDS-PAGE and MALDI-TOF MS. Results S. mutans ribose 5-phosphate isomerase A was successfully expressed in E. coli in

  14. Histone H2A and H4 N-terminal tails are positioned by the MEP50 WD repeat protein for efficient methylation by the PRMT5 arginine methyltransferase.

    Science.gov (United States)

    Burgos, Emmanuel S; Wilczek, Carola; Onikubo, Takashi; Bonanno, Jeffrey B; Jansong, Janina; Reimer, Ulf; Shechter, David

    2015-04-10

    The protein arginine methyltransferase PRMT5 is complexed with the WD repeat protein MEP50 (also known as Wdr77 or androgen coactivator p44) in vertebrates in a tetramer of heterodimers. MEP50 is hypothesized to be required for protein substrate recruitment to the catalytic domain of PRMT5. Here we demonstrate that the cross-dimer MEP50 is paired with its cognate PRMT5 molecule to promote histone methylation. We employed qualitative methylation assays and a novel ultrasensitive continuous assay to measure enzyme kinetics. We demonstrate that neither full-length human PRMT5 nor the Xenopus laevis PRMT5 catalytic domain has appreciable protein methyltransferase activity. We show that histones H4 and H3 bind PRMT5-MEP50 more efficiently compared with histone H2A(1-20) and H4(1-20) peptides. Histone binding is mediated through histone fold interactions as determined by competition experiments and by high density histone peptide array interaction studies. Nucleosomes are not a substrate for PRMT5-MEP50, consistent with the primary mode of interaction via the histone fold of H3-H4, obscured by DNA in the nucleosome. Mutation of a conserved arginine (Arg-42) on the MEP50 insertion loop impaired the PRMT5-MEP50 enzymatic efficiency by increasing its histone substrate Km, comparable with that of Caenorhabditis elegans PRMT5. We show that PRMT5-MEP50 prefers unmethylated substrates, consistent with a distributive model for dimethylation and suggesting discrete biological roles for mono- and dimethylarginine-modified proteins. We propose a model in which MEP50 and PRMT5 simultaneously engage the protein substrate, orienting its targeted arginine to the catalytic site.

  15. Cross-talk between the cytosolic mevalonate and the plastidial methylerythritol phosphate pathways in tobacco bright yellow-2 cells.

    Science.gov (United States)

    Hemmerlin, Andréa; Hoeffler, Jean-François; Meyer, Odile; Tritsch, Denis; Kagan, Isabelle A; Grosdemange-Billiard, Catherine; Rohmer, Michel; Bach, Thomas J

    2003-07-18

    In plants, two pathways are utilized for the synthesis of isopentenyl diphosphate, the universal precursor for isoprenoid biosynthesis. The key enzyme of the cytoplasmic mevalonic acid (MVA) pathway is 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR). Treatment of Tobacco Bright Yellow-2 (TBY-2) cells by the HMGR-specific inhibitor mevinolin led to growth reduction and induction of apparent HMGR activity, in parallel to an increase in protein representing two HMGR isozymes. Maximum induction was observed at 24 h. 1-Deoxy-d-xylulose (DX), the dephosphorylated first precursor of the plastidial 2-C-methyl-d-erythritol 4-phosphate (MEP) pathway, complemented growth inhibition by mevinolin in the low millimolar concentration range. Furthermore, DX partially re-established feedback repression of mevinolin-induced HMGR activity. Incorporation studies with [1,1,1,4-2H4]DX showed that sterols, normally derived from MVA, in the presence of mevinolin are synthesized via the MEP pathway. Fosmidomycin, an inhibitor of 1-deoxy-d-xylulose-5-phosphate reductoisomerase, the second enzyme of the MEP pathway, was utilized to study the reverse complementation. Growth inhibition by fosmidomycin of TBY-2 cells could be partially overcome by MVA. Chemical complementation was further substantiated by incorporation of [2-13C]MVA into plastoquinone, representative of plastidial isoprenoids. Best rates of incorporation of exogenous stably labeled precursors were observed in the presence of both inhibitors, thereby avoiding internal isotope dilution.

  16. Diffusion tensor tractography of pyramidal tracts in patients with brainstem and intramedullary spinal cord tumors: Relationship with motor deficits and intraoperative MEP changes.

    Science.gov (United States)

    Czernicki, Tomasz; Maj, Edyta; Podgórska, Anna; Kunert, Przemysław; Prokopienko, Marek; Nowak, Arkadiusz; Cieszanowski, Andrzej; Marchel, Andrzej

    2017-09-01

    To evaluate whether pyramidal tracts course alterations observed in diffusion tensor tractography (DTT) in cases of brainstem and intramedullary spinal cord tumors reflect patient clinical status and prognosis. For this purpose, we assessed in 17 patients relationships between pyramidal tracts course alterations observed in DTT (classified into four categories: unaffected; displaced or interspaced; partially disintegrated and completely disintegrated) performed on a 1.5 Tesla scanner and the presence of preoperative motor deficits, changes observed in motor evoked potentials (MEPs) records at the beginning of the operation, deterioration of the MEPs records during the operation, and perioperative deterioration of muscle strength. We found that, if the picture of pyramidal tracts in DTT was worse, motor deficit was more common (P = 0.062). This observation was even more evident (P = 0.027), when cases with at least partially destroyed pyramidal tracts were compared with cases with normal or at most displaced or interspaced by tumor but still preserved pyramidal tracts. Significant relationships were also found between changes in DTT and abnormal MEP records at the beginning of the operation (P = 0.032) and perioperative deterioration of muscle strength (P = 0.0058). A close relationship was found between pyramidal tracts course alterations in DTT imaging and preoperative motor status and especially with changes in the MEP records at the beginning of the operation. DTT may be a method that allows the better planning of brainstem and intramedullary spinal cord tumors operations and may help in the risk assessment of postoperative motor deficits. 3 Technical Efficacy: Stage 4 J. MAGN. RESON. IMAGING 2017;46:715-723. © 2017 International Society for Magnetic Resonance in Medicine.

  17. Spared Primary Motor Cortex and the Presence of MEP in Cerebral Palsy Dictate the Responsiveness to tDCS During Gait Training

    Directory of Open Access Journals (Sweden)

    Luanda Collange Grecco

    2016-07-01

    Full Text Available The current priority of investigations involving transcranial direct current stimulation (tDCS and neurorehabilitation is to identify biomarkers associated with the positive results of the interventions such that respondent and non-respondent patients can be identified in the early phases of treatment. The aims were to determine whether; 1 present motor evoked potential (MEP and, 2 injuries involving the primary motor cortex, are associated with tDCS-enhancement in functional outcome following gait training in children with cerebral palsy (CP. We reviewed the data from our parallel, randomized, sham-controlled, double-blind studies. Fifty-six children with spastic CP received gait training (either treadmill training or virtual reality training and tDCS (active or sham. Univariate and multivariate logistic regression analyses were employed to identify clinical, neurophysiologic and neuroanatomic predictors associated with the responsiveness to treatment with tDCS. MEP presence during the initial evaluation and the subcortical injury were associated with positive effects in the functional results. The logistic regression revealed that present MEP was a significant predictor for the six-minute walk test (p=0.003 and gait speed (p=0.028, whereas the subcortical injury was a significant predictor of gait kinematics (p=0.013 and gross motor function (p = 0.021. In this preliminary study involving children with CP, two important prediction factors of good responses to anodal tDCS combined with gait training were identified. Apparently, MEP (integrity of the corticospinal tract and subcortical location of the brain injury exerted different influences on aspects related to gait, such as velocity and kinematics.

  18. Draft Genome Sequence of Highly Virulent Race 4/Biovar 3 of Ralstonia solanacearum CaRs_Mep Causing Bacterial Wilt in Zingiberaceae Plants in India

    Science.gov (United States)

    Munjal, Vibhuti; Sheoran, Neelam; Prameela, Thekkan Puthiyaveedu; Suseelabhai, Rajamma; Aggarwal, Rashmi; Jain, Rakesh Kumar; Eapen, Santhosh J.

    2017-01-01

    ABSTRACT The genome of Ralstonia solanacearum CaRs_Mep, a race 4/biovar 3/phylotype I bacterium causing wilt in small cardamom and other Zingiberaceae plants, was sequenced. Analysis of the 5.7-Mb genome sequence will aid in better understanding of the genetic determinants of host range, host jump, survival, pathogenicity, and virulence of race 4 of R. solanacearum. PMID:28057749

  19. Protein arginine methyltransferase Prmt5-Mep50 methylates histones H2A and H4 and the histone chaperone nucleoplasmin in Xenopus laevis eggs.

    Science.gov (United States)

    Wilczek, Carola; Chitta, Raghu; Woo, Eileen; Shabanowitz, Jeffrey; Chait, Brian T; Hunt, Donald F; Shechter, David

    2011-12-01

    Histone proteins carry information contained in post-translational modifications. Eukaryotic cells utilize this histone code to regulate the usage of the underlying DNA. In the maturing oocytes and eggs of the frog Xenopus laevis, histones are synthesized in bulk in preparation for deposition during the rapid early developmental cell cycles. During this key developmental time frame, embryonic pluripotent chromatin is established. In the egg, non-chromatin-bound histones are complexed with storage chaperone proteins, including nucleoplasmin. Here we describe the identification and characterization of a complex of the protein arginine methyltransferase 5 (Prmt5) and the methylosome protein 50 (Mep50) isolated from Xenopus eggs that specifically methylates predeposition histones H2A/H2A.X-F and H4 and the histone chaperone nucleoplasmin on a conserved motif (GRGXK). We demonstrate that nucleoplasmin (Npm), an exceedingly abundant maternally deposited protein, is a potent substrate for Prmt5-Mep50 and is monomethylated and symmetrically dimethylated at Arg-187. Furthermore, Npm modulates Prmt5-Mep50 activity directed toward histones, consistent with a regulatory role for Npm in vivo. We show that H2A and nucleoplasmin methylation appears late in oogenesis and is most abundant in the laid egg. We hypothesize that these very abundant arginine methylations are constrained to pre-mid blastula transition events in the embryo and therefore may be involved in the global transcriptional repression found in this developmental time frame.

  20. Increasing diterpene yield with a modular metabolic engineering system in E. coli: comparison of MEV and MEP isoprenoid precursor pathway engineering.

    Science.gov (United States)

    Morrone, Dana; Lowry, Luke; Determan, Mara K; Hershey, David M; Xu, Meimei; Peters, Reuben J

    2010-02-01

    Engineering biosynthetic pathways in heterologous microbial host organisms offers an elegant approach to pathway elucidation via the incorporation of putative biosynthetic enzymes and characterization of resulting novel metabolites. Our previous work in Escherichia coli demonstrated the feasibility of a facile modular approach to engineering the production of labdane-related diterpene (20 carbon) natural products. However, yield was limited (engineering system. With MEP pathway enhancement, it was found that pyruvate supplementation of rich media and simultaneous overexpression of three genes (idi, dxs, and dxr) resulted in the greatest increase in diterpene yield, indicating distributed metabolic control within this pathway. Incorporation of a heterologous MEV pathway in bioreactor grown cultures resulted in significantly higher yields than MEP pathway enhancement. We have established suitable growth conditions for diterpene production levels ranging from 10 to >100 mg/L of E. coli culture. These amounts are sufficient for nuclear magnetic resonance analyses, enabling characterization of enzymatic products and hence, pathway elucidation. Furthermore, these results represent an up to >1,000-fold improvement in diterpene production from our facile, modular platform, with MEP pathway enhancement offering a cost effective alternative with reasonable yield. Finally, we reiterate here that this modular approach is expandable and should be easily adaptable to the production of any terpenoid natural product.

  1. Spectroscopic (infrared, Raman, UV and NMR) analysis, Gaussian hybrid computational investigation (MEP maps/HOMO and LUMO) on cyclohexanone oxime

    Science.gov (United States)

    Ramalingam, S.; Karabacak, M.; Periandy, S.; Puviarasan, N.; Tanuja, D.

    2012-10-01

    In the present analysis, FT-IR/FT-Raman spectra of the cyclohexanone oxime (CHO, C6H11NO) are recorded. The observed vibrational frequencies are assigned and the computational calculations are carried out by HF and DFT (B3LYP and B3PW91) methods with 6-311++G(d,p) basis set and the corresponding results are tabulated. In order to yield good coherence with observed values, the calculated frequencies are scaled by appropriate scale factors. The complete assignments are performed on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method. The alternation of structure of cyclohexanone due to the substitution of NOH is investigated. The vibrational sequence pattern of the molecule related to the substitutions is analyzed. Comparison of the observed fundamental vibrational frequencies of CHO and calculated results by density functional (B3LYP and B3PW91) and HF methods indicates that B3LYP is superior to the scaled HF and B3PW91 approach for molecular vibrational problems. Moreover, 13C NMR and 1H NMR chemical shifts are calculated by using the gauge independent atomic orbital (GIAO) method with HF/B3LYP/B3PW91 methods and the same basis set. A study on the electronic properties; absorption wavelengths, excitation energy, dipole moment and frontier molecular orbital energies, are performed by HF and DFT methods. The calculated HOMO and LUMO energies show that charge transfer occurs within the molecule. Besides frontier molecular orbitals (FMO), molecular electrostatic potential (MEP) was performed. NLO properties and Mulliken charges of the CHO was also calculated and interpreted. The thermodynamic properties (heat capacity, entropy, and enthalpy) of the title compound at different temperatures are calculated in gas phase.

  2. Effects of mutagenesis of aspartic acid residues in the putative phosphoribosyl diphosphate binding site of Escherichia coli phosphoribosyl diphosphate synthetase on metal ion specificity and ribose 5-phosphate binding

    DEFF Research Database (Denmark)

    Willemoës, Martin; Nilsson, Dan; Hove-Jensen, Bjarne

    1996-01-01

    an increase in KM for ribose 5-phosphate in the presence of at least one of the divalent metal ions Mg2+, Mn2+, Co2+, or Cd2+, with the most dramatic changes revealed by the D220E and D220F enzymes in the presence of Co2+ and the D221A enzyme in the presence of Mn2+ or Co2+. The D220F and D221A enzymes both...... showed large decreases in Vapp in the presence of the various divalent metal ions, except for the D221A enzyme in the presence of Co2+. Vapp of the D220E enzyme was similar to that of the wild-type enzyme in the presence of Mg2+, Mn2+, or Cd2+, whereas the Vapp was increased in the presence of Co2+. Vapp...... enzymes were dependent on the metal ion present, suggesting a function of the investigated aspartic acid residues both in the binding of ribose 5-phosphate, possibly via a divalent metal ion, and in the interaction with a divalent metal ion during catalysis...

  3. Homology of pyridoxal-5'-phosphate-dependent aminotransferases with the cobC (cobalamin synthesis), nifS (nitrogen fixation), pabC (p-aminobenzoate synthesis) and malY (abolishing endogenous induction of the maltose system) gene products.

    Science.gov (United States)

    Mehta, P K; Christen, P

    1993-01-15

    Bacterial deletion mutants have indicated that the gene products of cobC, nifS, pabC and malY participate in important metabolic pathways, i.e. cobalamin synthesis, nitrogen fixation, synthesis of p-aminobenzoate and the regulation of the maltose system, respectively. However, the proteins themselves and their specific functions have not yet been identified. In the course of our studies on the evolutionary relationships among aminotransferases, we have found that the above gene products are homologous to aminotransferases. Profile analysis [Gribskov, M., Lüthy, R. & Eisenberg, D. (1990) Methods Enzymol. 183, 146-159] based on the amino acid sequences of certain subgroups of aminotransferases as probes attributed significant Z scores in the range 5-20 SD to the deduced amino acid sequences of the above gene products as included in the protein data base. Reciprocal profile analyses confirmed the homologies. All known aminotransferases are pyridoxal-5'-phosphate-dependent enzymes and catalyze the reversible transfer of amino groups from amino acids to oxo acids. The sequence homologies suggest that the above gene products are aminotransferases or other closely related pyridoxal-5'-phosphate-dependent enzymes probably catalyzing transformations of amino acids involving cleavage of a bond at C alpha.

  4. Overexpression of SrUGT85C2 from Stevia reduced growth and yield of transgenic Arabidopsis by influencing plastidial MEP pathway.

    Science.gov (United States)

    Guleria, Praveen; Masand, Shikha; Yadav, Sudesh Kumar

    2014-04-15

    The transcript expression of a gene SrUGT85C2 has been documented for direct relation with steviol glycoside content in Stevia plant. Steviol glycoside and gibberellin biosynthetic routes are divergent branches of methyl erythritol-4 phosphate (MEP) pathway. So, SrUGT85C2 might be an influencing gibberellin content. Hence in the present study, transgenic Arabidopsis thaliana overexpressing SrUGT85C2 cDNA from Stevia rebaudiana was developed to check its effect on gibberellin accumulation and related plant growth parameters. The developed transgenics showed a noteworthy decrease of 78-83% in GA3 content. Moreover, the transgenics showed a gibberellin deficient phenotype comprising stunted hypocotyl length, reduced shoot growth and a significant fall in relative water content. Transgenics also showed 17-37 and 64-76% reduction in chlorophyll a and chlorophyll b contents, respectively. Reduction in photosynthetic pigments could be responsible for the noticed significant decrease in plant biomass. Like steviol glycoside and gibberellin biosynthesis, chlorophyll biosynthesis also occurs from the precursors isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP) of MEP pathway in the plastids. The observed downregulated expression of genes encoding MEP pathway enzymes geranyl geranyl diphosphate synthase (GGDPS), copalyl diphosphate synthase (CDPS), kaurenoic acid oxidase (KAO), chlorophyll synthetase and chlorophyll a oxygenase in transgenics overexpressing SrUGT85C2 might be responsible for the reduction in gibberellins as well as chlorophyll. This study has documented for the first time the regulatory role of SrUGT85C2 in the biosynthesis of steviol glycoside, gibberellins and chlorophyll.

  5. Dft Study on 4(5-Imidazole-Carbaldehyde-N(5-Phenylthiosemicarbazone (Imtph: Nmr Shielding Tensors, Thermodynamic Parameters, Nbo Analysis, Molecular Electrostatic Potential (Mep, Homo and Lumo Studies

    Directory of Open Access Journals (Sweden)

    Masoome Sheikhi

    2014-03-01

    Full Text Available The density functional theory (DFT calculations at the level of B3LYP/6-31G was carried out on the structure 4(5-Imidazole-carbaldehyde-N(5-phenylthiosemicarbazone (ImTPh in gas phase using Gaussian 03. Dipole moment (Debye, energy of structure formation (HF; kcal/mol and point group, NMR parameters such as isotropic shielding (σiso and anisotropic shielding (σaniso, σ11, σ22 and σ33 obtained. Also thermodynamic properties and natural bond orbitals (NBO were calculated. Besides, the frontier molecular orbital (FMO analysis and the molecular electrostatic potential (MEP of the compound were investigated by theoretical calculations.

  6. Purification and characterization of pyridoxal-5'-phosphate hydrolase from tobacco%烟草磷酸吡哆醛水解酶的分离纯化与表征

    Institute of Scientific and Technical Information of China (English)

    马娅萍; 黄龙全; 张剑韵

    2012-01-01

    Pyridoxal-5'-phosphate hydrolase was purified from tobacco by ammonium sulfate,DEAE-Sepharose Fast Flow ion exchange chromatography,Sephadex G-100 gel filtration,SP Sephadex C-25 ion exchange chromatography. Further investigations of pyridoxal-5'-phosphate hydrolase, reported herein, lead to the conclusion that this enzyme was purified approximately 119. 6-fold, the recovery of 28. 49% activity, Sephadex G-100 gel filtration and SDS-PAGE showed that the molecular weight of the enzyme was 49. 6 kDa,and the molecular weight of subunit was approximately 25 kDa; The enzyme had an optimal temperature and pH at 50℃ and 5. 5, respectively. It was enhanced by Mg2+ ,Ca2+ and Mn2+ , yet inhibited by chelating agent EDTA , which inhibited effect was relieved after added Mg2+; under optimal conditions, the Km values for pyridoxal-5'-phosphate (PLP) and pyridoxamine-5 -phos-phate (PMP) were 0. 23 mmol/L,0. 56 mmol/L,respectively.%采用硫酸铵沉淀、DEAE-Sepharose Fast Flow阴离子交换、Sephadex G-100凝胶过滤和SP Sephadex C-25阳离子交换柱层析等步骤,对烟草磷酸吡哆醛水解酶进行了分离纯化.结果表明:该酶被纯化了119.6倍,得率为28.49%,经凝胶过滤和SDS-PAGE测得该酶的全分子量为49.6 kDa,亚基分子量约为25 kDa;该酶最适温度为50℃,最适反应pH为5.5;Mg2+、Ca2+、Mn2+等对该酶有激活作用,金属离子螯合剂EDTA对酶有抑制作用,加入Mg2+后抑制作用得到解除;在最适反应条件下,测得反应底物磷酸吡哆醛(PLP)和磷酸吡哆胺(PMP)的Km值分别为0.23 mmol/L和0.56 mmol/L.

  7. Re-exploring the high-throughput potential of microextraction techniques, SPME and MEPS, as powerful strategies for medical diagnostic purposes. Innovative approaches, recent applications and future trends.

    Science.gov (United States)

    Pereira, Jorge; Silva, Catarina Luís; Perestrelo, Rosa; Gonçalves, João; Alves, Vera; Câmara, José S

    2014-03-01

    The human population continues to grow exponentially in the fast developing and most populated countries, whereas in Western Europe it is getting older and older each year. This inevitably raises the demand for better and more efficient medical services without increasing the economic burden in the same proportion. To meet these requirements, improvement of medical diagnosis is certainly a key aspect to consider. Therefore, we need powerful analytical methodologies able to go deeper and further in the characterization of human metabolism and identification of disease biomarkers and endogenous molecules in body fluids and tissues. The ultimate goal is to have a reliable and early medical diagnosis, mitigating the disease complications as much as possible. Microextraction techniques (METs) represent a key step in these analytical methodologies by providing samples in the suitable volumes and purification levels necessary for the characterization of the target analytes. In this aspect, solid-phase microextraction (SPME) and, more recently, microextraction by packed sorbent (MEPS), are powerful sample preparation techniques, characterized by their reduced time of analysis, low solvent consumption, and broad application. Moreover, as miniaturized techniques, they can be easily automatized to have a high-throughput performance in the clinical environment. In this review, we explore some of the most interesting MEPS and SPME applications, focusing on recent trends and applications to medical diagnostic, particularly the in vivo and near real time applications.

  8. 顶复门原虫类异戊二烯生物合成途径及其关键酶的研究进展%Advance in Isoprenoids Biosynthesis Pathway and DOXP Reductoisomerase in Apicomplexa

    Institute of Scientific and Technical Information of China (English)

    廖申权; 吴彩艳; 戚南山; 吕敏娜; 覃宗华; 孙铭飞

    2012-01-01

    顶复门原虫包括疟原虫(Plasmodium spp.)、刚地弓形虫(Toxoplasma gondii)、艾美耳球虫(Eimeria spp.)、锥虫(Trypanosoma spp.)、泰勒虫(Theileria spp.)及巴贝斯虫(Babesia spp.)等一大类引起严重人畜疾病的寄生性原虫.顶复门原虫利用2C-甲基-D-赤藓糖醇-4-磷酸(MEP)途径合成类异戊二烯前体物质,这些化合物对于维持顶复门原虫的生存具有十分重要的作用.1-脱氧-D-木酮糖-5-磷酸(DOXP)还原异构酶是MEP途径的关键酶,对其作用机理及抑制剂的筛选研究已取得重要进展.论文对顶复门原虫类异戊二烯的MEP途径,DOXP还原异构酶的作用机理及靶标研究进展进行综述.

  9. Lipophilic prodrugs of FR900098 are antimicrobial against Francisella novicida in vivo and in vitro and show GlpT independent efficacy.

    Directory of Open Access Journals (Sweden)

    Elizabeth S McKenney

    Full Text Available Bacteria, plants, and algae produce isoprenoids through the methylerythritol phosphate (MEP pathway, an attractive pathway for antimicrobial drug development as it is present in prokaryotes and some lower eukaryotes but absent from human cells. The first committed step of the MEP pathway is catalyzed by 1-deoxy-D-xylulose 5-phosphate reductoisomerase (DXR/MEP synthase. MEP pathway genes have been identified in many biothreat agents, including Francisella, Brucella, Bacillus, Burkholderia, and Yersinia. The importance of the MEP pathway to Francisella is demonstrated by the fact that MEP pathway mutations are lethal. We have previously established that fosmidomycin inhibits purified MEP synthase (DXR from F. tularensis LVS. FR900098, the acetyl derivative of fosmidomycin, was found to inhibit the activity of purified DXR from F. tularensis LVS (IC(50=230 nM. Fosmidomycin and FR900098 are effective against purified DXR from Mycobacterium tuberculosis as well, but have no effect on whole cells because the compounds are too polar to penetrate the thick cell wall. Fosmidomycin requires the GlpT transporter to enter cells, and this is absent in some pathogens, including M. tuberculosis. In this study, we have identified the GlpT homologs in F. novicida and tested transposon insertion mutants of glpT. We showed that FR900098 also requires GlpT for full activity against F. novicida. Thus, we synthesized several FR900098 prodrugs that have lipophilic groups to facilitate their passage through the bacterial cell wall and bypass the requirement for the GlpT transporter. One compound, that we termed "compound 1," was found to have GlpT-independent antimicrobial activity. We tested the ability of this best performing prodrug to inhibit F. novicida intracellular infection of eukaryotic cell lines and the caterpillar Galleria mellonella as an in vivo infection model. As a lipophilic GlpT-independent DXR inhibitor, compound 1 has the potential to be a broad

  10. Improving peppermint essential oil yield and composition by metabolic engineering.

    Science.gov (United States)

    Lange, Bernd Markus; Mahmoud, Soheil Seyed; Wildung, Mark R; Turner, Glenn W; Davis, Edward M; Lange, Iris; Baker, Raymond C; Boydston, Rick A; Croteau, Rodney B

    2011-10-11

    Peppermint (Mentha × piperita L.) was transformed with various gene constructs to evaluate the utility of metabolic engineering for improving essential oil yield and composition. Oil yield increases were achieved by overexpressing genes involved in the supply of precursors through the 2C-methyl-D-erythritol 4-phosphate (MEP) pathway. Two-gene combinations to enhance both oil yield and composition in a single transgenic line were assessed as well. The most promising results were obtained by transforming plants expressing an antisense version of (+)-menthofuran synthase, which is critical for adjusting the levels of specific undesirable oil constituents, with a construct for the overexpression of the MEP pathway gene 1-deoxy-D-xylulose 5-phosphate reductoisomerase (up to 61% oil yield increase over wild-type controls with low levels of the undesirable side-product (+)-menthofuran and its intermediate (+)-pulegone). Elite transgenic lines were advanced to multiyear field trials, which demonstrated consistent oil yield increases of up to 78% over wild-type controls and desirable effects on oil composition under commercial growth conditions. The transgenic expression of a gene encoding (+)-limonene synthase was used to accumulate elevated levels of (+)-limonene, which allows oil derived from transgenic plants to be recognized during the processing of commercial formulations containing peppermint oil. Our study illustrates the utility of metabolic engineering for the sustainable agricultural production of high quality essential oils at a competitive cost.

  11. Effection of Pyridoxal- 5 '- phosphate on Determination of Alanine Aminotransferase activities%5'-磷酸吡哆醛对血清丙氨酸氨基转移酶活性测定的影响

    Institute of Scientific and Technical Information of China (English)

    朱柏林

    2012-01-01

    目的 研究丙氨酸氨基转移酶(Alanine Aminotraasferase,ALT) 检测试剂中 5'- 磷酸吡哆醛(Pyrldoxal - 5'-phosphate,PLP )的添加对血清ALT活性测定的影响.方法 以山东潍坊康华生物技术有限公司生产的丙氨酸氨基转移酶试剂(按照IFCC推荐方法配制,不含PLP)和在该品牌试剂中加入5'-磷酸吡哆醛溶液,分别用这两种试剂测定相同的新鲜临床标本280例,并对检测结果进行统计学比较.结果 使用含PLP的IFCC配方试剂较不含 PLP试剂的检测结果明显增高.结论 康华公司生产的丙氨酸氨基转移酶试剂添加PLP比较不添加PLP ALT活性增加近5%-40%,且两种试剂的ALT检测结果不能通过简单系数实现转换.

  12. Effects of mutagenesis of aspartic acid residues in the putative phosphoribosyl diphosphate binding site of Escherichia coli phosphoribosyl diphosphate synthetase on metal ion specificity and ribose-5-phosphate binding

    DEFF Research Database (Denmark)

    Willemoës, Martin; Nilsson, Dan; Hove-Jensen, Bjarne

    1996-01-01

    The three conserved aspartic acid residues of the 5-phospho-d-ribosyl a-1-diphosphate binding site (213-GRDCVLVDDMIDTGGT-228) of Escherichia coli phosphoribosyl diphosphate synthetase were studied by analysis of the mutant enzymes D220E, D220F, D221A, D224A, and D224S. The mutant enzymes showed...... an increase in KM for ribose 5-phosphate in the presence of at least one of the divalent metal ions Mg2+, Mn2+, Co2+, or Cd2+, with the most dramatic changes revealed by the D220E and D220F enzymes in the presence of Co2+ and the D221A enzyme in the presence of Mn2+ or Co2+. The D220F and D221A enzymes both...... showed large decreases in Vapp in the presence of the various divalent metal ions, except for the D221A enzyme in the presence of Co2+. Vapp of the D220E enzyme was similar to that of the wild-type enzyme in the presence of Mg2+, Mn2+, or Cd2+, whereas the Vapp was increased in the presence of Co2+. Vapp...

  13. Effects of mutagenesis of aspartic acid residues in the putative phosphoribosyl diphosphate binding site of Escherichia coli phosphoribosyl diphosphate synthetase on metal ion specificity and ribose 5-phosphate binding

    DEFF Research Database (Denmark)

    Willemoës, Martin; Nilsson, Dan; Hove-Jensen, Bjarne

    1996-01-01

    The three conserved aspartic acid residues of the 5-phospho-D-ribosyl α-1-diphosphate binding site (213-GRDCVLVDDMIDTGGT-228) of Escherichia coli phosphoribosyl diphosphate synthetase were studied by analysis of the mutant enzymes D220E, D220F, D221A, D224A, and D224S. The mutant enzymes showed...... an increase in KM for ribose 5-phosphate in the presence of at least one of the divalent metal ions Mg2+, Mn2+, Co2+, or Cd2+, with the most dramatic changes revealed by the D220E and D220F enzymes in the presence of Co2+ and the D221A enzyme in the presence of Mn2+ or Co2+. The D220F and D221A enzymes both...... showed large decreases in Vapp in the presence of the various divalent metal ions, except for the D221A enzyme in the presence of Co2+. Vapp of the D220E enzyme was similar to that of the wild-type enzyme in the presence of Mg2+, Mn2+, or Cd2+, whereas the Vapp was increased in the presence of Co2+. Vapp...

  14. Expression of the xylulose 5-phosphate phosphoketolase gene, xpkA, from Lactobacillus pentosus MD363 is induced by sugars that are fermented via the phosphoketolase pathway and is repressed by glucose mediated by CcpA and the mannose phosphoenolpyruvate phosphotransferase system

    NARCIS (Netherlands)

    Posthuma, C.C.; Bader, R.; Engelmann, R.; Postma, P.W.; Hengstenberg, W.; Pouwels, P.H.

    2002-01-01

    Purification of xylulose 5-phosphate phosphoketolase (XpkA), the central enzyme of the phosphoketolase pathway (PKP) in lactic acid bacteria, and cloning and sequence analysis of the encoding gene, xpkA, from Lactobacillus pentosus MD363 are described, xpkA encodes a 788-amino-acid protein with a ca

  15. 番茄dxs基因的克隆及在大肠杆菌中的颜色互补%Cloning of Deoxyoxylulose-5-phosphate Synthase Gene from Tomato and Its Color Complementation in E. coli

    Institute of Scientific and Technical Information of China (English)

    潘夕春; 陈敏; 刘颜; 廖志华

    2007-01-01

    用RT-PCR(反转录-聚合酶链式反应)的方法从番茄中克隆到5-磷酸脱氧木酮糖合成酶(Deoxyoxylulose-5-phosphate synthase, DXS)基因编码区(记为ledxs),并构建了ledxs原核表达载体pTrcLeDXS.将携带番茄红素生物合成途径上香叶基香叶基焦磷酸合成酶(geranylgeranyl pyrophosphate synthase,crtE),八氢番茄红素合成酶 (phytoene synthase,crtB),八氢番茄红素脱饱和酶(phytoene desaturase,crtI)3个关键酶基因的原核表达载体pAC-LYC转入大肠杆菌XL1-Blue.将pTrcLeDXS转入该重组工程菌,获得番茄红素工程菌.将该菌用于构建颜色互补平板,并进行发酵培养以检测番茄红素表达量.颜色互补平板上的菌斑呈现鲜艳的红色.经过21 h的培养番茄红素的产量达到605.25 μg·L-1.结果显示:ledxs能明显推动类胡萝卜素途径向番茄红素合成的方向流动.

  16. An animal homolog of plant Mep/Amt transporters promotes ammonia excretion by the anal papillae of the disease vector mosquito Aedes aegypti.

    Science.gov (United States)

    Chasiotis, Helen; Ionescu, Adrian; Misyura, Lidiya; Bui, Phuong; Fazio, Kimberly; Wang, Jason; Patrick, Marjorie; Weihrauch, Dirk; Donini, Andrew

    2016-05-01

    The transcripts of three putative ammonia (NH3/NH4 (+)) transporters, Rhesus-like glycoproteins AeRh50-1, AeRh50-2 and Amt/Mep-like AeAmt1 were detected in the anal papillae of larval Aedes aegypti Quantitative PCR studies revealed 12-fold higher transcript levels of AeAmt1 in anal papillae relative to AeRh50-1, and levels of AeRh50-2 were even lower. Immunoblotting revealed AeAmt1 in anal papillae as a pre-protein with putative monomeric and trimeric forms. AeAmt1 was immunolocalized to the basal side of the anal papillae epithelium where it co-localized with Na(+)/K(+)-ATPase. Ammonium concentration gradients were measured adjacent to anal papillae using the scanning ion-selective electrode technique (SIET) and used to calculate ammonia efflux by the anal papillae. dsRNA-mediated reductions in AeAmt1 decreased ammonia efflux at larval anal papillae and significantly increased ammonia levels in hemolymph, indicating a principal role for AeAmt1 in ammonia excretion. Pharmacological characterization of ammonia transport mechanisms in the anal papillae suggests that, in addition to AeAmt1, the ionomotive pumps V-type H(+)-ATPase and Na(+)/K(+)-ATPase as well as NHE3 are involved in ammonia excretion at the anal papillae.

  17. Molecular structure, vibrational, UV, NMR, HOMO-LUMO, MEP, NLO, NBO analysis of 3,5 di tert butyl 4 hydroxy benzoic acid

    Science.gov (United States)

    Mathammal, R.; Sangeetha, K.; Sangeetha, M.; Mekala, R.; Gadheeja, S.

    2016-09-01

    In this study, we report a combined experimental and theoretical study on molecular structure and vibrational spectra of 3,5 di tert butyl 4 hydroxy benzoic acid. The properties of title compound have been evaluated by quantum chemical calculation (DFT) using B3LYP functional and 6-31 + G (d, p) as basis set. IR Spectra has been recorded using Fourier transform infrared spectroscopy (FT-IR) in the region 4000-400 cm-1. The vibrational assignment of the calculated normal modes has been made on the basis set. The isotropic chemical shifts computed by 13C and 1H NMR (Nuclear Magnetic Resonance) analyses also show good agreement with experimental observations. The theoretical UV-Vis spectrum of the compound are used to study the visible absorption maxima (λ max). The structure activity relationship have been interpreted by mapping electrostatic potential surface (MEP), which is valuable information for the quality control of medicines and drug receptor interactions. The Mullikan charges, HOMO (Highest Occupied Molecular Orbital) - LUMO (Lowest Unoccupied Molecular Orbital) energy are analyzed. HOMO-LUMO energy gap and other related molecular properties are also calculated. The Natural Bond Orbital (NBO) analysis is carried out to investigate the various intra and inter molecular interactions of molecular system. The Non-linear optical properties such as dipole moment (μ), polarizability (αtot) and molecular first order hyperpolarizability (β) of the title compound are computed with B3LYP/6-31 + G (d,p) level of theory.

  18. Analytical Profiling of Bioactive Phenolic Compounds in Argan (Argania spinosa) Leaves by Combined Microextraction by Packed Sorbent (MEPS) and LC-DAD-MS/MS.

    Science.gov (United States)

    Mercolini, Laura; Protti, Michele; Saracino, Maria Addolorata; Mandrone, Manuela; Antognoni, Fabiana; Poli, Ferruccio

    2016-01-01

    The argan tree (Argania spinosa) is an endemic species from south-western Morocco. Argan-based preparations have been widely used in Moroccan traditional medicine for their biological properties, as well as for several cosmetic purposes. Whereas kernel, pulp of fruit and trunk have been extensively studied for their nutritional and pharmacological effects, relatively little is known about argan tree leaves. The main purpose of the present study is to investigate and characterise the bioactive phenolic fractions in both crude and aqueous extracts derived from argan tree leaves. A qualitative profile of the antioxidant phenolic compounds in argan leaves was obtained by means of structural hypothesis based on UV spectra and mass spectrometric fragmentation patterns. Moreover, selected phenolics were quantified in argan leaves by using a fully validated method based on liquid chromatography coupled to diode array detection and tandem mass spectrometry (LC-DAD-MS/MS). All the extracts were purified by a fast and reliable microextraction by packed sorbent (MEPS) procedure, before analysing them by LC-MS/MS. Based on retention times, mass spectrometric fragmentation and UV spectra, 13 phenolic compounds were identified or tentatively elucidated from crude and aqueous extracts derived from Argania spinosa leaves, while seven compounds were quantified in both extracts. The obtained results could represent a first step towards a complete characterisation of the argan plant, its bioactive profiling and the valorisation of its by-products as a source of potentially beneficial bioactive molecules. Copyright © 2015 John Wiley & Sons, Ltd.

  19. Molecular structure, vibrational spectra, NLO and MEP analysis of bis[2-hydroxy-кO-N-(2-pyridyl)-1-naphthaldiminato-кN]zinc(II).

    Science.gov (United States)

    Tanak, Hasan; Toy, Mehmet

    2013-11-01

    The molecular geometry and vibrational frequencies of bis[2-hydroxy-кO-N-(2-pyridyl)-1-naphthaldiminato-кN]zinc(II) in the ground state have been calculated by using the Hartree-Fock (HF) and density functional method (B3LYP) with 6-311G(d,p) basis set. The results of the optimized molecular structure are presented and compared with the experimental X-ray diffraction. The energetic and atomic charge behavior of the title compound in solvent media has been examined by applying the Onsager and the polarizable continuum model. To investigate second order nonlinear optical properties of the title compound, the electric dipole (μ), linear polarizability (α) and first-order hyperpolarizability (β) were computed using the density functional B3LYP and CAM-B3LYP methods with the 6-31+G(d) basis set. According to our calculations, the title compound exhibits nonzero (β) value revealing second order NLO behavior. In addition, DFT calculations of the title compound, molecular electrostatic potential (MEP), frontier molecular orbitals, and thermodynamic properties were performed at B3LYP/6-311G(d,p) level of theory. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. Molecular structure, vibrational spectra, NLO and MEP analysis of bis[2-hydroxy-кO-N-(2-pyridyl)-1-naphthaldiminato-кN]zinc(II)

    Science.gov (United States)

    Tanak, Hasan; Toy, Mehmet

    2013-11-01

    The molecular geometry and vibrational frequencies of bis[2-hydroxy-кO-N-(2-pyridyl)-1-naphthaldiminato-кN]zinc(II) in the ground state have been calculated by using the Hartree-Fock (HF) and density functional method (B3LYP) with 6-311G(d,p) basis set. The results of the optimized molecular structure are presented and compared with the experimental X-ray diffraction. The energetic and atomic charge behavior of the title compound in solvent media has been examined by applying the Onsager and the polarizable continuum model. To investigate second order nonlinear optical properties of the title compound, the electric dipole (μ), linear polarizability (α) and first-order hyperpolarizability (β) were computed using the density functional B3LYP and CAM-B3LYP methods with the 6-31+G(d) basis set. According to our calculations, the title compound exhibits nonzero (β) value revealing second order NLO behavior. In addition, DFT calculations of the title compound, molecular electrostatic potential (MEP), frontier molecular orbitals, and thermodynamic properties were performed at B3LYP/6-311G(d,p) level of theory.

  1. Bisphosphonate inhibitors reveal a large elasticity of plastidic isoprenoid synthesis pathway in isoprene-emitting hybrid aspen.

    Science.gov (United States)

    Rasulov, Bahtijor; Talts, Eero; Kännaste, Astrid; Niinemets, Ülo

    2015-06-01

    Recently, a feedback inhibition of the chloroplastic 1-deoxy-D-xylulose 5-phosphate (DXP)/2-C-methyl-D-erythritol 4-phosphate (MEP) pathway of isoprenoid synthesis by end products dimethylallyl diphosphate (DMADP) and isopentenyl diphosphate (IDP) was postulated, but the extent to which DMADP and IDP can build up is not known. We used bisphosphonate inhibitors, alendronate and zoledronate, that inhibit the consumption of DMADP and IDP by prenyltransferases to gain insight into the extent of end product accumulation and possible feedback inhibition in isoprene-emitting hybrid aspen (Populus tremula × Populus tremuloides). A kinetic method based on dark release of isoprene emission at the expense of substrate pools accumulated in light was used to estimate the in vivo pool sizes of DMADP and upstream metabolites. Feeding with fosmidomycin, an inhibitor of DXP reductoisomerase, alone or in combination with bisphosphonates was used to inhibit carbon input into DXP/MEP pathway or both input and output. We observed a major increase in pathway intermediates, 3- to 4-fold, upstream of DMADP in bisphosphonate-inhibited leaves, but the DMADP pool was enhanced much less, 1.3- to 1.5-fold. In combined fosmidomycin/bisphosphonate treatment, pathway intermediates accumulated, reflecting cytosolic flux of intermediates that can be important under strong metabolic pull in physiological conditions. The data suggested that metabolites accumulated upstream of DMADP consist of phosphorylated intermediates and IDP. Slow conversion of the huge pools of intermediates to DMADP was limited by reductive energy supply. These data indicate that the DXP/MEP pathway is extremely elastic, and the presence of a significant pool of phosphorylated intermediates provides an important valve for fine tuning the pathway flux.

  2. Resistance of Francisella novicida to Fosmidomycin Associated with Mutations in the Glycerol-3-Phosphate Transporter

    Directory of Open Access Journals (Sweden)

    Ryan S Mackie

    2012-08-01

    Full Text Available The methylerythritol phosphate (MEP pathway is essential in most prokaryotes and some lower eukaryotes but absent from human cells, and is a validated target for antimicrobial drug development. The formation of MEP is catalyzed by 1-deoxy-D-xylulose 5-phosphate reductoisomerase (DXR. MEP pathway genes have been identified in many Category A and B biothreat agents, including Francisella tularensis, which causes the zoonosis tularemia. Fosmidomycin inhibits purified Francisella DXR. This compound also inhibits the growth of F. tularensis NIH B38, F. novicida and F. tularensis subsp. holarctica LVS bacteria. Related compounds such as FR900098 and lipophilic prodrugs of FR900098 have been developed to improve the bioavailability of these DXR inhibitors. In disc-inhibition assays with these compounds, we observed breakthrough colonies of F. novicida in the presence of fosmidomycin, suggesting spontaneous development of fosmidomycin resistance (FosR. FosR bacteria had decreased sensitivity to both fosmidomycin and FR900098. The two most likely targets for the development of mutants would be the DXR enzyme or the glycerol-3-phosphate transporter (GlpT that allows entry of fosmidomycin into the bacteria. Sensitivity of FosR F. novicida bacteria to compound 1 was not abated suggesting that spontaneous resistance is not due to mutation of DXR. We thus predicted that the glpT transporter may be mutated leading to this resistant phenotype. Supporting this, transposon insertion mutants at the glpT locus were also found to be resistant to fosmidomycin. DNA sequencing of four different spontaneous FosR colonies demonstrated a variety of deletions in the glpT coding region. The overall frequency of FosR mutations in F. novicida was determined to be 6.3 x 10-8. Thus we conclude that one mechanism of resistance of F. novicida to fosmidomycin is caused by mutations in GlpT. This is the first description of mutations in Francisella leading to fosmidomycin

  3. A new and fast methodology to assess oxidative damage in cardiovascular diseases risk development through eVol-MEPS-UHPLC analysis of four urinary biomarkers.

    Science.gov (United States)

    Mendes, Berta; Silva, Pedro; Mendonça, Isabel; Pereira, Jorge; Câmara, José S

    2013-11-15

    In this work, a new, fast and reliable methodology using a digitally controlled microextraction by packed sorbent (eVol(®)-MEPS) followed by ultra-high pressure liquid chromatography (UHPLC) analysis with photodiodes (PDA) detection, was developed to establish the urinary profile levels of four putative oxidative stress biomarkers (OSBs) in healthy subjects and patients evidencing cardiovascular diseases (CVDs). This data was used to verify the suitability of the selected OSBs (uric acid-UAc, malondialdehyde-MDA, 5-(hydroxymethyl)uracil-5-HMUra and 8-hydroxy-2'-deoxyguanosine-8-oxodG) as potential biomarkers of CVDs progression. Important parameters affecting the efficiency of the extraction process were optimized, particularly stationary phase selection, pH influence, sample volume, number of extraction cycles and washing and elution volumes. The experimental conditions that allowed the best extraction efficiency, expressed in terms of total area of the target analytes and data reproducibility, includes a 10 times dilution and pH adjustment of the urine samples to 6.0, followed by a gradient elution through the C8 adsorbent with 5 times 50 µL of 0.01% formic acid and 3×50 µL of 20% methanol in 0.01% formic acid. The chromatographic separation of the target analytes was performed with a HSS T3 column (100 mm × 2.1 mm, 1.7 µm in particle size) using 0.01% formic acid 20% methanol at 250 µL min(-1). The methodology was validated in terms of selectivity, linearity, instrumental limit of detection (LOD), method limit of quantification (LOQ), matrix effect, accuracy and precision (intra-and inter-day). Good results were obtained in terms of selectivity and linearity (r(2)>0.9906), as well as the LOD and LOQ, whose values were low, ranging from 0.00005 to 0.72 µg mL(-1) and 0.00023 to 2.31 µg mL(-1), respectively. The recovery results (91.1-123.0%), intra-day (1.0-8.3%), inter-day precision (4.6-6.3%) and the matrix effect (60.1-110.3%) of eVol(®)-MEPS

  4. The effect of MEP pathway and other inhibitors on the intracellular localization of a plasma membrane-targeted, isoprenylable GFP reporter protein in tobacco BY-2 cells [v1; ref status: indexed, http://f1000r.es/yx

    Directory of Open Access Journals (Sweden)

    Michael Hartmann

    2013-08-01

    Full Text Available We have established an in vivo visualization system for the geranylgeranylation of proteins in a stably transformed tobacco BY-2 cell line, based on the expression of a dexamethasone-inducible GFP fused to the carboxy-terminal basic domain of the rice calmodulin CaM61, which naturally bears a CaaL geranylgeranylation motif (GFP-BD-CVIL. By using pathway-specific inhibitors it was demonstrated that inhibition of the methylerythritol phosphate (MEP pathway with known inhibitors like oxoclomazone and fosmidomycin, as well as inhibition of the protein geranylgeranyltransferase type 1 (PGGT-1, shifted the localization of the GFP-BD-CVIL protein from the membrane to the nucleus. In contrast, the inhibition of the mevalonate (MVA pathway with mevinolin did not affect the localization. During the present work, this test system has been used to examine the effect of newly designed inhibitors of the MEP pathway and inhibitors of sterol biosynthesis such as squalestatin, terbinafine and Ro48-8071. In addition, we also studied the impact of different post-prenylation inhibitors or those suspected to affect the transport of proteins to the plasma membrane on the localization of the geranylgeranylable fusion protein GFP-BD-CVIL.

  5. 经颅磁刺激运动诱发电位对脊髓损伤的评价及法医学意义%The Evaluation of SCI by TMS-MEP and Its Forensic Significance

    Institute of Scientific and Technical Information of China (English)

    杨蕾; 刘兴本; 朱镕霆; 徐晓明; 郑传斐; 周禹鑫

    2013-01-01

    目的 为脊髓损伤(spinal cord injury,SCI)的法医临床学鉴定寻找客观且准确的检查方法.方法 采用经颅磁刺激运动诱发电位(transcranial magnetic stimulation-motor evoked potential,TMS-MEP)测定68例SCI患者(颈段损伤23例,胸腰段损伤45例)拇短展肌和胫前肌的皮层起始潜伏期、N1峰潜伏期、中枢运动传导时间(central motor conduction time,CMCT)和波宽,并以30例正常人作为对照,比较两组差异. 结果 实验组随拇短展肌、胫前肌肌力下降或消失,皮层起始潜伏期、N1峰潜伏期、CMCT延长,波宽增宽,且实验组中的2、3级肌力者上述指标均高于对照组(P<0.05).结论 TMS-MEP检测可以直接、客观地反映脊髓锥体束的运动功能状态,为法医学鉴定提供更客观、准确的依据.%Objective To find an objective and accurate examination for evaluation of spinal cord injury (SCI) in forensic clinical medicine.Methods The onset latency of cortex,peak latency of N1,central motor conduction time (CMCT) and wave width of the abductor pollicis brevis and the anterior tibialis were calculated by transcranial magnetic stimulation-motor evoked potential (TMS-MEP).The data of 68 patients suffered from SCI including 23 cervical levels and 45 thoracolumbar levels were collected and compared with that of 30 normal controls.Results In experimental group,when the muscle strength of the abductor pollicis brevis or the anterior tibialis decreased or disappeared,the onset latency of cortex,the peak latency of N1,and CMCT prolonged and the wave width broadened.And these indexes of grade 2 and 3 muscle strength in experimental group were higher than that in the control group (P<0.05).Conclusion The TMS-MEP can determine directly and objectively the motor functional status of pyramidal tract of spinal cord in order to provide more accurate and objective evidences in forensic medicine.

  6. Development of an image-based screening system for inhibitors of the plastidial MEP pathway and of protein geranylgeranylation [v2; ref status: indexed, http://f1000r.es/5p9

    Directory of Open Access Journals (Sweden)

    Michael Hartmann

    2015-08-01

    Full Text Available In a preceding study we have recently established an in vivo visualization system for the geranylgeranylation of proteins in a stably transformed tobacco BY-2 cell line, which involves expressing a dexamethasone-inducible GFP fused to the prenylable, carboxy-terminal basic domain of the rice calmodulin CaM61, which naturally bears a CaaL geranylgeranylation motif (GFP-BD-CVIL. By using pathway-specific inhibitors it was there demonstrated that inhibition of the methylerythritol phosphate (MEP pathway with oxoclomazone and fosmidomycin, as well as inhibition of protein geranylgeranyl transferase type 1 (PGGT-1, shifted the localization of the GFP-BD-CVIL protein from the membrane to the nucleus. In contrast, the inhibition of the mevalonate (MVA pathway with mevinolin did not affect this localization. Furthermore, in this initial study complementation assays with pathway-specific intermediates confirmed that the precursors for the cytosolic isoprenylation of this fusion protein are predominantly provided by the MEP pathway. In order to optimize this visualization system from a more qualitative assay to a statistically trustable medium or a high-throughput screening system, we established now new conditions that permit culture and analysis in 96-well microtiter plates, followed by fluorescence microscopy. For further refinement, the existing GFP-BD-CVIL cell line was transformed with an estradiol-inducible vector driving the expression of a RFP protein, C-terminally fused to a nuclear localization signal (NLS-RFP. We are thus able to quantify the total number of viable cells versus the number of inhibited cells after various treatments. This approach also includes a semi-automatic counting system, based on the freely available image processing software. As a result, the time of image analysis as well as the risk of user-generated bias is reduced to a minimum. Moreover, there is no cross-induction of gene expression by dexamethasone and estradiol

  7. Development of an image-based screening system for inhibitors of the plastidial MEP pathway and of protein geranylgeranylation [v1; ref status: indexed, http://f1000r.es/4vt

    Directory of Open Access Journals (Sweden)

    Michael Hartmann

    2015-01-01

    Full Text Available We have recently established an in vivo visualization system for the geranylgeranylation of proteins in a stably transformed tobacco BY-2 cell line, which involves expressing a dexamethasone-inducible GFP fused to the prenylable, carboxy-terminal basic domain of the rice calmodulin CaM61, which naturally bears a CaaL geranylgeranylation motif (GFP-BD-CVIL. By using pathway-specific inhibitors it was demonstrated that inhibition of the methylerythritol phosphate (MEP pathway with oxoclomazone and fosmidomycin, as well as inhibition of protein geranylgeranyl transferase type 1 (PGGT-1, shifted the localization of the GFP-BD-CVIL protein from the membrane to the nucleus. In contrast, the inhibition of the mevalonate (MVA pathway with mevinolin did not affect this localization. Furthermore, complementation assays with pathway-specific intermediates confirmed that the precursors for the cytosolic isoprenylation of this fusion protein are predominantly provided by the MEP pathway. In order to optimize this visualization system from a more qualitative assay to a statistically trustable medium or a high-throughput screening system, we established new conditions that permit culture and analysis in 96-well microtiter plates, followed by fluorescence microscopy. For further refinement, the existing GFP-BD-CVIL cell line was transformed with an estradiol-inducible vector driving the expression of a RFP protein, C-terminally fused to a nuclear localization signal (NLS-RFP. We are thus able to quantify the total number of viable cells versus the number of inhibited cells after various treatments. This approach also includes a semi-automatic counting system, based on the freely available image processing software. As a result, the time of image analysis as well as the risk of user-generated bias is reduced to a minimum. Moreover, there is no cross-induction of gene expression by dexamethasone and estradiol, which is an important prerequisite for this test

  8. Evolutionary diversification and characterization of the eubacterial gene family encoding DXR type II, an alternative isoprenoid biosynthetic enzyme.

    Science.gov (United States)

    Carretero-Paulet, Lorenzo; Lipska, Agnieszka; Pérez-Gil, Jordi; Sangari, Félix J; Albert, Victor A; Rodríguez-Concepción, Manuel

    2013-09-03

    Isoprenoids constitute a vast family of natural compounds performing diverse and essential functions in all domains of life. In most eubacteria, isoprenoids are synthesized through the methylerythritol 4-phosphate (MEP) pathway. The production of MEP is usually catalyzed by deoxyxylulose 5-phosphate reductoisomerase (DXR-I) but a few organisms use an alternative DXR-like enzyme (DXR-II). Searches through 1498 bacterial complete proteomes detected 130 sequences with similarity to DXR-II. Phylogenetic analysis identified three well-resolved clades: the DXR-II family (clustering 53 sequences including eleven experimentally verified as functional enzymes able to produce MEP), and two previously uncharacterized NAD(P)-dependent oxidoreductase families (designated DLO1 and DLO2 for DXR-II-like oxidoreductases 1 and 2). Our analyses identified amino acid changes critical for the acquisition of DXR-II biochemical function through type-I functional divergence, two of them mapping onto key residues for DXR-II activity. DXR-II showed a markedly discontinuous distribution, which was verified at several levels: taxonomic (being predominantly found in Alphaproteobacteria and Firmicutes), metabolic (being mostly found in bacteria with complete functional MEP pathways with or without DXR-I), and phenotypic (as no biological/phenotypic property was found to be preferentially distributed among DXR-II-containing strains, apart from pathogenicity in animals). By performing a thorough comparative sequence analysis of GC content, 3:1 dinucleotide frequencies, codon usage and codon adaptation indexes (CAI) between DXR-II sequences and their corresponding genomes, we examined the role of horizontal gene transfer (HGT), as opposed to an scenario of massive gene loss, in the evolutionary origin and diversification of the DXR-II subfamily in bacteria. Our analyses support a single origin of the DXR-II family through functional divergence, in which constitutes an exceptional model of

  9. FT-IR, HOMO-LUMO, NBO, MEP analysis and molecular docking study of 3-Methyl-4-{(E)-[4-(methylsulfanyl)-benzylidene]amino}1H-1,2,4-triazole-5(4H)-thione.

    Science.gov (United States)

    Panicker, C Yohannan; Varghese, Hema Tresa; Manjula, P S; Sarojini, B K; Narayana, B; War, Javeed Ahamad; Srivastava, S K; Van Alsenoy, C; Al-Saadi, Abdulaziz A

    2015-01-01

    FT-IR spectrum of 3-Methyl-4-{(E)-[4-(methylsulfanyl)-benzylidene]amino}1H-1,2,4-triazole-5(4H)-thione was recorded and analysed. The vibrational wavenumbers were computed and at HF and DFT levels of theory. The data obtained from wavenumber calculations are used to assign the vibrational bands obtained in the IR spectrum. The NH stretching wavenumber is red shifted in the IR spectrum from the computed value, which indicates the weakening of the NH bond. The geometrical parameters of the title compound are in agreement with the XRD results. NBO analysis, HOMO-LUMO, first and second order hyperpolarizability and molecular electrostatic potential results are also reported. From the MEP map it is evident that the negative regions are localized over the sulphur atoms and N3 atom of triazole ring and the maximum positive region is localized on NH group, indicating a possible site for nucleophilic attack. Prediction of Activity Spectra analysis of the title compound predicts anti-tuberculostic activity with probability to be active value of 0.543. Molecular docking studies reveal that the triazole nitrogen atoms and the thione sulphur atom play vital role in bonding and results draw us to the conclusion that the compound might exhibit anti-tuberculostic activity.

  10. FT-IR, molecular structure, HOMO-LUMO, MEP, NBO analysis and first order hyperpolarizability of Methyl 4,4″-difluoro-5";-methoxy-1,1";:3";,1″-terphenyl-4";-carboxylate

    Science.gov (United States)

    Sheena Mary, Y.; Yohannan Panicker, C.; Narayana, B.; Samshuddin, S.; Sarojini, B. K.; Van Alsenoy, C.

    2014-12-01

    Methyl 4,4″-difluoro-5";-methoxy-1,1";:3";,1″-terphenyl-4";-carboxylate was prepared by the aromatization of a cyclohexenone derivative, Methyl 4,6-bis(4-fluorophenyl)-2-oxocyclohex-3-ene-1-carboxylate using iodine and methanol at reflux conditions. The structure of the compound was confirmed by IR and single crystal X-ray diffraction studies. FT-IR spectrum was recorded and analyzed. The crystal structure is also described. The vibrational wavenumbers are calculated using HF and DFT methods and are assigned with the help of potential energy distribution. The geometrical parameters of the title compound obtained from XRD studies are in agreement with the calculated (DFT) values. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. According to the MEP analysis, negative region (red) is mainly over the carbonyl group showing large activity. The calculated hyperpolarizability of the title compound is greater than that of the standard NLO material urea and the title compound is an attractive object for future studies of nonlinear optical properties.

  11. Identification and Characterization of a 1-Deoxy-D-xylulose 5-phosphate Synthase Gene From Pinus kesiya var.langbianensis%思茅松1-脱氧-D-木酮糖-5-磷酸合酶(DXS)基因的克隆及功能分析

    Institute of Scientific and Technical Information of China (English)

    王毅; 周旭; 毕玮; 杨宇明; 李江; 王娟

    2015-01-01

    1-脱氧-D-木酮糖-5-磷酸合酶(DXS)是甲基-D-赤藓醇-4-磷酸(MEP)途径中的第一个酶,也是限速酶.本文根据思茅松(Pinus kesiya var.langbianensis (A.Chev.)Gaussen)树皮转录组数据分析结果,获得思茅松DXS基因片段,然后根据获得的基因片段设计特异引物,运用RT-PCR和RACE技术从思茅松树皮中克隆得到完整的DXS基因(PkDXS1).PkDXS1基因的cDNA全长序列2 888 bp,含有1个2 223 bp的开放阅读框(ORF),编码740个氨基酸,该基因推断的蛋白与赤松(Pinus densiflora Siebold&Zucc)DXS蛋白的相似性为99%,与欧洲云杉(Piceaabies (L.)H.Karst.)DXS的相似性为97%;经氨基酸序列比对,推断思茅松DXS具有高等植物DXS酶特有的叶绿体转运肽,二磷酸硫胺结合位点和转酮醇酶结构域.半定量RT-PCR检测表明树皮的创伤促进DXS基因的表达.

  12. Medical Expenditure Panel Survey (MEPS) Query Tool

    Data.gov (United States)

    U.S. Department of Health & Human Services — MEPSnet HC Query Tool MEPSnet/Household Component provides easy access to nationally representative statistics of health care use, expenditures, sources of payment,...

  13. MEPs : ban hammer, sickle and swastika

    Index Scriptorium Estoniae

    2005-01-01

    Europarlamendi liikmete Vytautas Landsbergise ja Jozsef Szajeri avalduse kohaselt tuleks Euroopa Liidus ettevalmistatava seaduse raames, mis keelustaks natsisümboli - haakristi - kasutamise, keelata ka kommunismi sümboolika kasutamine

  14. MEPs : ban hammer, sickle and swastika

    Index Scriptorium Estoniae

    2005-01-01

    Europarlamendi liikmete Vytautas Landsbergise ja Jozsef Szajeri avalduse kohaselt tuleks Euroopa Liidus ettevalmistatava seaduse raames, mis keelustaks natsisümboli - haakristi - kasutamise, keelata ka kommunismi sümboolika kasutamine

  15. Site-directed mutation of pyridoxine 5'-phosphate oxidase from Bombyx mori and activity assay of the mutants in vitro%家蚕磷酸吡哆醇氧化酶的体外定点突变及其活性鉴定

    Institute of Scientific and Technical Information of China (English)

    童宁; 张剑韵; 黄龙全

    2011-01-01

    [目的]研究家蚕Bombyx mori磷酸吡哆醇氧化酶(pyridoxine 5’-phosphate oxidase,PNPO)个别保守氨基酸残基对PNPO酶活性的影响.[方法]用重叠延伸法把氨基酸残基Lys111 (AAA)突变为Glu (GAA),Ser160(AGC)定点突变为Ala(GCC);构建重组表达载体,在大肠杆菌Escherichia coli Rosetta中诱导表达,经亲和纯化后进行酶活鉴定.[结果]重组蛋白的分子量约为45.0 kDa.体外酶活分析发现,家蚕氨基酸残基Lys111突变体K11lE活性降低了约78.0%,Ser160突变体S160A的活性降低了67.4%.[结论]结果提示氨基酸残基Lys111和Ser160对维持家蚕PNPO的酶活性有重要作用.本研究明确了家蚕磷酸吡哆醇氧化酶个别保守氨基酸残基的酶学功能.%[Aim] To study the effects of single conserved amino acid residue of pyridoxine 5'-phosphate oxidase (PNPO) from Bombyx mori on its activity. [Methods] Lys111 (AAA) and Ser160 (AGC) , two of the most conserved residues, were mutated to Glu ( GAA) and Ala ( GCC ) by using over-lap extension, respectively. The obtained expression plasmids were over-expressed in Escherichia coli Rosetta by IPTG induction, and then the expressed products were purified with affinity chromatography and the activity of the purified PNPO were determined. [ Results ] The molecular mass of the target recombinant protein was ~45.0 kDa. Compared with the wild type PNPO, the activities of the mutants K111E and S160A were reduced by 78.0% and 67.4% , respectively. [ Conclusion] The results suggest that the residues Lys and Ser are important to maintain the activity of PNPO. This study confirms the significance of single conserved amino acid residues on the catalytic function of PNPO of B. Mori.

  16. The effect of MEP pathway and other inhibitors on the intracellular localization of a plasma membrane-targeted, isoprenylable GFP reporter protein in tobacco BY-2 cells [v2; ref status: indexed, http://f1000r.es/2af

    Directory of Open Access Journals (Sweden)

    Michael Hartmann

    2013-11-01

    Full Text Available We have established an in vivo visualization system for the geranylgeranylation of proteins in a stably transformed tobacco BY-2 cell line, based on the expression of a dexamethasone-inducible GFP fused to the carboxy-terminal basic domain of the rice calmodulin CaM61, which naturally bears a CaaL geranylgeranylation motif (GFP-BD-CVIL. By using pathway-specific inhibitors it was demonstrated that inhibition of the methylerythritol phosphate (MEP pathway with known inhibitors like oxoclomazone and fosmidomycin, as well as inhibition of the protein geranylgeranyltransferase type 1 (PGGT-1, shifted the localization of the GFP-BD-CVIL protein from the membrane to the nucleus. In contrast, the inhibition of the mevalonate (MVA pathway with mevinolin did not affect the localization. During the present work, this test system has been used to examine the effect of newly designed inhibitors of the MEP pathway and inhibitors of sterol biosynthesis such as squalestatin, terbinafine and Ro48-8071. In addition, we also studied the impact of different post-prenylation inhibitors or those suspected to affect the transport of proteins to the plasma membrane on the localization of the geranylgeranylable fusion protein GFP-BD-CVIL.

  17. Intracellular adenosine 3',5'-phosphate formation is essential for down-regulation of surface adenosine 3',5'-phosphate receptors in Dictyostelium

    NARCIS (Netherlands)

    Haastert, Peter J.M. van

    1994-01-01

    Dictyostelium discoideum cells contain cell surface cyclic AMP (cAMP) receptors that bind cAMP as a first messenger and intracellular cAMP receptors that bind cAMP as a second messenger. Prolonged incubation of Dictyostelium cells with cAMP induces a sequential process of phosphorylation, sequestrat

  18. Comparability study of ALT detection by three biochemistry analyzer systems and the influence to ALT activity with the existence of coenzyme pyridoxal-5-phosphate.%辅酶磷酸吡哆醛的存在对三种生化检测系统测定丙氨酸氨基转移酶活性的影响及其可比性研究

    Institute of Scientific and Technical Information of China (English)

    张建忠; 沈春燕

    2011-01-01

    To study the difference and comparability of alanine aminotransferase (ALT) results detected by three biochemistry analyzer systems. Methods The ALT activities of 164 cases of patients and 152 cases of healthy adults were detected by DADE Dimension RXL system, Johnson Vitros-350 system that containing pyridoxal-5-phosphate in their reagents and HITACHI7170 system that not containing pyridoxal-5-phosphate in its reagents,respectively. According to the document EP9-A described by the NCCLS, two group parallel contrast tests had being established: In the first group, ALT detected by HITACHI7170 system was selected as the standard method and DADE Dimension RXL system as the empirical method. In the other group, ALT detected by DADE Dimension RXL system was selected as the standard method and Johnson Vitros-350 system as the empirical method. Results The assay resuits of ALT activity detected by DADE Dimension RXL and Johnson Vitros-350 systems were higher(20.2%~56.5%)than that detected by HITACHI7170 system and there was no significant difference between DADE Dimension RXL system and Johnson Vitros-350 system. The parallel contrast tests also showed that there was an obvious systematic error between HITACHI7170 system and DADE Dimension RXL system, but there was a good correlation between DADE Dimension RXL system and Vitros-350 system. Conclusion Because of the difference of methodology the results of ALT activity detected by DADE Dimension RXL and Johnson Vitros-350 biochemistry analyzer systems couldn't obtain consistency with those by HITACHI7170 system, but there was a higher consistency between DADE Dimension RXL system and Vitros-350 system.%目的 探讨不同生化检测系统间测定丙氨酸氨基转移酶(ALT)活性结果的差异及其可比性.方法 使用ALT试剂中含有磷酸吡哆醛的DADE Dimension RXL检测系统、强生Vitros-350检测系统以及ALT试剂中未含有磷酸吡哆醛HITACHI7170检测系统同时测试164例患者和152例

  19. Transcription profiling data set of different states of Mycoplasma gallisepticum

    Directory of Open Access Journals (Sweden)

    Tatiana A. Semashko

    2017-03-01

    Here we present the data for transcription profiling of M. gallisepticum under different types of exposures: genetic knock-out mutants, cell culture exposed to sublethal concentrations of antibiotics and well-characterized heat stress effect. Mutants have transposon insertion to hypothetical membrane protein, lactate dehydrogenase, helicase with unknown function, 1-deoxy-d-xylulose 5-phosphate reductoisomerase or potential sigma factor. For inhibition of important cell systems, treatment with carbonyl cyanide m-chlorophenylhydrazone (CCCP, novobiocin or tetracycline were chosen. Data are available via NCBI Gene Expression Omnibus (GEO with the accession number GSE85777 (http://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE85777

  20. Lithuanian MEP loses his immunity / Rokas M. Tracevskis

    Index Scriptorium Estoniae

    Tracevskis, Rokas M.

    2010-01-01

    7. septembril otsustas Euroopa Parlament parlamendisaadiku Viktor Uspaskihhi puutumatuse ära võtta, kuna teda kahtlustatakse Tööerakonna raamatupidamise võltsimises. Viktor Uspaskihhi poliitilisest tegevusest

  1. Switching substrate specificity of AMT/MEP/ Rh proteins

    Science.gov (United States)

    Neuhäuser, Benjamin; Dynowski, Marek; Ludewig, Uwe

    2014-01-01

    In organisms from all kingdoms of life, ammonia and its conjugated ion ammonium are transported across membranes by proteins of the AMT/Rh family. Efficient and successful growth often depends on sufficient ammonium nutrition. The proteins mediating this transport, the so called Ammonium Transporter (AMT) or Rhesus like (Rh) proteins, share a very similar trimeric overall structure and a high sequence similarity even throughout the kingdoms. Even though structural components of the transport mechanism, like an external substrate recruitment site, an essential twin histidine pore motif, a phenylalanine gate and the hydrophobic pore are strongly conserved and have been analyzed in detail by molecular dynamic simulations and mutational studies, the substrate(s), which pass the central pores of the AMT/Rh subunits, NH4+, NH3 + H+, NH4+ + H+ or NH3, are still a matter of debate for most proteins, including the best characterized AmtB protein from Escherichia coli. The lack of a robust expression system for functional analysis has hampered proof of structural and mutational studies, although the NH3 transport function for Rh-like proteins is rarely disputed. In plant transporters belonging to the subfamily AMT1, transport is associated with electrical currents, while some plant transporters, notably of the AMT2 type, were suggested to transport NH3 across the membrane, without associated ionic currents. Here we summarize data in favor of each substrate for the distinct AMT/Rh classes, discuss mutants and how they differ in structure and functionality. A common mechanism with deprotonation and subsequent NH3 transport through the central subunit pore is suggested. PMID:25483282

  2. Microelectronics and Special Education. CET/MEP Information Sheet.

    Science.gov (United States)

    Council for Educational Technology, London (England).

    Used as an additional aid by the teacher, microelectronics can assist mentally and physically handicapped children to meet educational objectives that have been specifically agreed upon for the individual child. Microelectronics can help deaf children develop speech production, communication skills, and grammar and sentence construction;…

  3. MEP : Political parties funded by bribes / Steven Paulikas

    Index Scriptorium Estoniae

    Paulikas, Steven

    2004-01-01

    Leedu Sotsiaaldemokraatliku Partei liikme, Euroopa Parlamendi saadiku Aloyzas Sakalase hinnangul finantseeritakse Leedu parteisid altkäemaksudest ja korruptsioonis süüdistatavad parlamendiliikmed tegutsesid oma parteide nimel

  4. Medical Expenditure Panel Survey (MEPS) Restricted Data Files

    Data.gov (United States)

    U.S. Department of Health & Human Services — Restricted Data Files Available at the Data Centers Researchers and users with approved research projects can access restricted data files that have not been...

  5. Lithuanian MEP loses his immunity / Rokas M. Tracevskis

    Index Scriptorium Estoniae

    Tracevskis, Rokas M.

    2010-01-01

    7. septembril otsustas Euroopa Parlament parlamendisaadiku Viktor Uspaskihhi puutumatuse ära võtta, kuna teda kahtlustatakse Tööerakonna raamatupidamise võltsimises. Viktor Uspaskihhi poliitilisest tegevusest

  6. The Role of the Phosphatidylinositol-5-Phosphate 4-Kinases in p53-Null Breast Cancers

    Science.gov (United States)

    2015-10-01

    mouse   model,   which   develop   triple   negative  basal  breast  cancers  rapidly  (~3  months),  and  the  MMTV...Cre  HER2/neu   transgenic   mouse   model   that   develop   mammary   carcinomas   with   100%   penetrance   by   six

  7. 基于2-C-甲基-D-赤藓糖醇-4磷酸途径的产紫槐二烯大肠杆菌构建及其补糖策略优化%Engineering MEP pathway in Escherichia coli for amorphadiene production and optimizing the bioprocess through glucose feeding control

    Institute of Scientific and Technical Information of China (English)

    汪建峰; 熊智强; 张嗣良; 王勇

    2014-01-01

    2-C-甲基-D-赤藻糖醇-4-磷酸(2-methyl-D-erythritol-4-phosphate,MEP)途径是大肠杆菌Escherichia coli唯一的萜类前体合成途径,研究表明它比甲羟戊酸(Mevalonate,MVA)途径具有更高的理论产率.但目前有关MEP途径的调控所知非常有限,故单独强化MEP途径对萜类异源合成产量的提高效果并不理想.研究中通过引入外源MEP途径基因强化E.coli萜类合成的遗传改造策略和发酵过程补糖控制优化,尝试更有效地释放MEP途径的潜力,建立青蒿素前体——紫槐二烯的高密度发酵过程.研究结果表明共表达阿维链霉菌Streptomyces avermitilis dxs2基因和枯草芽胞杆菌Bacillus subtilis idi基因可使紫槐二烯的摇瓶发酵产量比野生菌株提高12.2倍.随后针对该菌株建立了高密度发酵过程,发现稳定期的中前期(24-72 h)是产物合成的关键期,通过稳定期补糖速率的调整,明显改善了产物合成速度,使紫槐二烯的产量从2.5 g/L提高到了4.85 g/L,但不影响产物积累的周期.考虑到72 h后菌体老化可能会影响产物合成,进一步采取了调整对数期的补糖速率控制菌体生长的策略,使紫槐二烯的产量达到6.1 g/L.研究结果为基于MEP途径的萜类异源合成工程菌构建及其发酵工艺的建立奠定了基础.

  8. De novo fragment-based design of inhibitors of DXS guided by spin-diffusion-based NMR spectroscopy

    NARCIS (Netherlands)

    Masini, T.; Pilger, J.; Kroezen, B. S.; Illarionov, B.; Lottmann, P.; Fischer, M.; Griesinger, C.; Hirsch, A. K. H.

    2014-01-01

    We applied for the first time an innovative ligand-based NMR methodology (STI) to a medicinal-chemistry project aimed at the development of inhibitors for the enzyme 1-deoxy-D-xylulose-5-phosphate synthase (DXS). DXS is the first enzyme of the 2C-methyl-D-erythritol-4-phosphate (MEP) pathway, presen

  9. The non-mevalonate isoprenoid biosynthesis of plants as a test system for drugs against malaria and pathogenic bacteria.

    Science.gov (United States)

    Zeidler, J; Schwender, J; Mueller, C; Lichtenthaler, H K

    2000-12-01

    Two plant test systems are presented in the search for new inhibitors of the non-mevalonate isoprenoid pathway. A derivative of clomazone appears to be an inhibitor of the deoxyxylulose 5-phosphate/methylerythritol 4-phosphate (DOXP/MEP) pathway of isoprenoid formation.

  10. A homogeneous, high-throughput assay for phosphatidylinositol 5-phosphate 4-kinase with a novel, rapid substrate preparation.

    Directory of Open Access Journals (Sweden)

    Mindy I Davis

    Full Text Available Phosphoinositide kinases regulate diverse cellular functions and are important targets for therapeutic development for diseases, such as diabetes and cancer. Preparation of the lipid substrate is crucial for the development of a robust and miniaturizable lipid kinase assay. Enzymatic assays for phosphoinositide kinases often use lipid substrates prepared from lyophilized lipid preparations by sonication, which result in variability in the liposome size from preparation to preparation. Herein, we report a homogeneous 1536-well luciferase-coupled bioluminescence assay for PI5P4Kα. The substrate preparation is novel and allows the rapid production of a DMSO-containing substrate solution without the need for lengthy liposome preparation protocols, thus enabling the scale-up of this traditionally difficult type of assay. The Z'-factor value was greater than 0.7 for the PI5P4Kα assay, indicating its suitability for high-throughput screening applications. Tyrphostin AG-82 had been identified as an inhibitor of PI5P4Kα by assessing the degree of phospho transfer of γ-(32P-ATP to PI5P; its inhibitory activity against PI5P4Kα was confirmed in the present miniaturized assay. From a pilot screen of a library of bioactive compounds, another tyrphostin, I-OMe tyrphostin AG-538 (I-OMe-AG-538, was identified as an ATP-competitive inhibitor of PI5P4Kα with an IC(50 of 1 µM, affirming the suitability of the assay for inhibitor discovery campaigns. This homogeneous assay may apply to other lipid kinases and should help in the identification of leads for this class of enzymes by enabling high-throughput screening efforts.

  11. Interaction of muscle glycogen phosphorylase b reconstituted from apoenzyme and analogs of pyridoxal-5'-phosphate with specific ligands.

    Science.gov (United States)

    Chebotareva, N A; Sugrobova, N P; Bulanova, L N; Poznanskaya, A A; Kurganov, B I; Gunar, V I

    1996-04-01

    Phosphorylase b from rabbit skeletal muscles was reconstituted with analogs of PLP containing residues -CH(2)-CH(2)-COOH, trans-CH=CH-COOH or -C=-COOH at position 5. Replacing native coenzyme in the phosphorylase molecule with any PLP analog tested leads to the decrease in the enzyme affinity for the allosteric inhibitor, FMN. Phosphorylase b reconstituted with analogs of PLP shows the greater ability for association in tetramers in the presence of 1 mM AMP than native enzyme.

  12. Structure-activity relationships of compounds targeting mycobacterium tuberculosis 1-deoxy-D-xylulose 5-phosphate synthase.

    Science.gov (United States)

    Mao, Jialin; Eoh, Hyungjin; He, Rong; Wang, Yuehong; Wan, Baojie; Franzblau, Scott G; Crick, Dean C; Kozikowski, Alan P

    2008-10-01

    We report on a target-based approach to identify possible Mycobacterium tuberculosis DXS inhibitors from the structure of a known transketolase inhibitor. A small focused library of analogs was assembled in order to begin elucidating some meaningful structure-activity relationships of 3-(4-chloro-phenyl)-5-benzyl-4H-pyrazolo[1,5-a]pyrimidin-7-one. Ultimately we found that 2-methyl-3-(4-fluorophenyl)-5-(4-methoxy-phenyl)-4H-pyrazolo[1,5-a]pyrimidin-7-one, although still weak, was able to inhibit M. tuberculosis DXS with an IC(50) of 10.6 microM.

  13. Structure–activity relationships of compounds targeting mycobacterium tuberculosis 1-deoxy-D-xylulose 5-phosphate synthase

    Science.gov (United States)

    Mao, Jialin; Eoh, Hyungjin; He, Rong; Wang, Yuehong; Wan, Baojie; Franzblau, Scott G.; Crick, Dean C.; Kozikowski, Alan P.

    2016-01-01

    We report on a target-based approach to identify possible Mycobacterium tuberculosis DXS inhibitors from the structure of a known transketolase inhibitor. A small focused library of analogs was assembled in order to begin elucidating some meaningful structure–activity relationships of 3-(4-chloro-phenyl)-5-benzyl-4H-pyrazolo[1,5-a]pyrimidin-7-one. Ultimately we found that 2-methyl-3-(4-fluorophenyl)-5-(4-meth-oxy-phenyl)-4H-pyrazolo[1,5-a]pyrimidin-7-one, although still weak, was able to inhibit M. tuberculosis DXS with an IC50 of 10.6 μM. PMID:18783951

  14. Septin 9 induces lipid droplets growth by a phosphatidylinositol-5-phosphate and microtubule-dependent mechanism hijacked by HCV

    Science.gov (United States)

    Akil, Abdellah; Peng, Juan; Omrane, Mohyeddine; Gondeau, Claire; Desterke, Christophe; Marin, Mickaël; Tronchère, Hélène; Taveneau, Cyntia; Sar, Sokhavuth; Briolotti, Philippe; Benjelloun, Soumaya; Benjouad, Abdelaziz; Maurel, Patrick; Thiers, Valérie; Bressanelli, Stéphane; Samuel, Didier; Bréchot, Christian; Gassama-Diagne, Ama

    2016-01-01

    The accumulation of lipid droplets (LD) is frequently observed in hepatitis C virus (HCV) infection and represents an important risk factor for the development of liver steatosis and cirrhosis. The mechanisms of LD biogenesis and growth remain open questions. Here, transcriptome analysis reveals a significant upregulation of septin 9 in HCV-induced cirrhosis compared with the normal liver. HCV infection increases septin 9 expression and induces its assembly into filaments. Septin 9 regulates LD growth and perinuclear accumulation in a manner dependent on dynamic microtubules. The effects of septin 9 on LDs are also dependent on binding to PtdIns5P, which, in turn, controls the formation of septin 9 filaments and its interaction with microtubules. This previously undescribed cooperation between PtdIns5P and septin 9 regulates oleate-induced accumulation of LDs. Overall, our data offer a novel route for LD growth through the involvement of a septin 9/PtdIns5P signalling pathway. PMID:27417143

  15. Crystal Structure Analyses of the Fosmidomycin-Target Enzyme from Plasmodium Falciparum

    Science.gov (United States)

    Umeda, Tomonobu; Kusakabe, Yoshio; Tanaka, Nobutada

    The human malaria parasite Plasmodium falciparum is responsible for the death of more than a million people each year. Fosmidomycin has proved to be efficient in the treatment of P. falciparum malaria through the inhibition of 1-deoxy-D-xylulose 5-phosphate reductoisomerase (DXR), an enzyme of the non-mevalonate pathway of isoprenoid biosynthesis, which is absent in humans. Crystal structure analyses of P. falciparum DXR (PfDXR) revealed that (i) an intrinsic flexibility of the PfDXR molecule accounts for the induced-fit movement to accommodate the bound inhibitor in the active site, and (ii) a cis arrangement of the oxygen atoms of the hydroxamate group of the bound inhibitor is essential for tight binding of the inhibitor to the active site metal. We believe that our study will serve as a useful guide to develop more potent PfDXR inhibitors.

  16. MEPS 2.0? EUROPARLIAMENTARIANS TALKING TO VOTERS IN THE INTERNET ERA

    Directory of Open Access Journals (Sweden)

    Stefano Braghiroli

    2010-09-01

    Full Text Available This paper systematically looks at the nature of MEPs’ internet-based “web tools” in the past EP legislature and at the extent to which their features reflect the complex nature of the EP environment (“Europeanization of communication”. To conduct this operation, a variety of structural and graphic features of MEPs’ websites have been identified, which have been made statistically analyzable, following a process of standardization and categorization, and were finally collected into a unique dataset. The preliminary figures obtained have been then controlled for a wide array of pluri-dimensional factors, operating both at micro-/individual-level and at macro-/country-level. Conceived as an explorative study towards clearer and more accurate understanding of MEPs’ internet-based communication styles and political strategies, our analysis aims at providing a stepping stone for further investigation in this direction.

  17. Multi-matrix assay of cortisol, cortisone and corticosterone using a combined MEPS-HPLC procedure.

    Science.gov (United States)

    Saracino, Maria A; Iacono, Corrado; Somaini, Lorenzo; Gerra, Gilberto; Ghedini, Nadia; Raggi, Maria A

    2014-01-01

    The development and validation of a bioanalytical assay for the simultaneous determination of cortisol, cortisone and corticosterone levels in several matrices, such as saliva, plasma, blood and urine samples have been described. The method is based on a rapid test which combines a microextraction by packed sorbent procedure and liquid chromatography-diode array technique. Chromatographic separation of the analytes (cortisol, cortisone and corticosterone) and the internal standard (methylprednisolone) was achieved in less than 10min on a reversed-phase pentafluorophenyl column using a mobile phase composed of phosphate buffer and acetonitrile. The assay was performed after an innovative microextraction procedure by means of C8 sorbent which guaranteed good clean-up of the matrices and satisfactory extraction yield of the analytes. Moreover, the method gave linear results over a range of 5-100ngmL(-1) and showed good selectivity and precision. This method was successfully applied for quantifying corticosteroids in specific matrices derived from some healthy volunteers in comparison to two socially diversified groups, namely former heroin addicts undergoing opioid replacement therapy and poly-drug abusers. Copyright © 2013 Elsevier B.V. All rights reserved.

  18. Performance analysis of endoreversible combined Carnot cycles based on new maximum efficient power (MEP) approach

    National Research Council Canada - National Science Library

    Maheshwari, Govind; Chaudhary, S; Somani, S.K

    2010-01-01

    The efficient power, defined as the product of power output and efficiency of the engine, is taken as the objective for performance analysis and optimization of an endoreversible combined Carnot heat...

  19. 78 FR 34346 - Proposed Information Collection; Comment Request; NIST MEP Advanced Manufacturing Jobs and...

    Science.gov (United States)

    2013-06-07

    ... Advanced Manufacturing Jobs and Innovation Accelerator Challenge (AMJIAC) Client Impact Survey AGENCY... information collection. The purpose of the Advanced Manufacturing Jobs and Innovation Accelerator Challenge... to support job creation, encourage economic development, and enhance the competitiveness of...

  20. Study to Develop Unified Investigative Capability and Policy Among the CVS, MEP, PSS, and RBS Programs.

    Science.gov (United States)

    1979-12-01

    43 0 -TOTAL PERSONNEL INVESTIGATIOMS................. 5. OISPOSITM Of PIRUL MESTMIATMS DCK ENINE RADIO LICEM OTHER A. Revoked...file accessed by a unique report generation language package developed specifically for use by PIRS. This software package provides data retrieval

  1. Advanced In-Space Propulsion (AISP): Micro Electrospray Propulsion (MEP) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Propulsion technology is often critical for space missions. High-value missions could be done with very small spacecraft, even CubeSats, but these...

  2. Enhanced C30 carotenoid production in Bacillus subtilis by systematic overexpression of MEP pathway genes

    NARCIS (Netherlands)

    Xue, Dan; Abdallah, Ingy I.; de Haan, Ilse E.M.; Sibbald, Mark J.J.B.; Quax, Wim J.

    2015-01-01

    Creating novel biosynthetic pathways and modulating the synthesis of important compounds are one of the hallmarks of synthetic biology. Understanding the key parameters controlling the flux of chemicals throughout a metabolic pathway is one of the challenges ahead. Isoprenoids are the most functiona

  3. An Application of Motor Evoked Potential (MEP) Method to Analyzing Human Motor Learning

    OpenAIRE

    志村, 邦義; 矢作, 晋; 笠井,達哉

    1996-01-01

    Until recently, drastic approach of motor learning in intact humans was not possible. The introduction of noninvasive techniques to stimulate the motor cortex in the present review permitted the testing and investigation of cortical motor outflow related to mechanisms in human motor learning. Human mapping studies, previously performed only during surgical procedures on patients with neurological disorders, can now be done with minimal discomfort. In the present brief review, therefore, we ha...

  4. Enhanced C30 carotenoid production in Bacillus subtilis by systematic overexpression of MEP pathway genes

    NARCIS (Netherlands)

    Xue, Dan; Abdallah, Ingy I.; de Haan, Ilse E.M.; Sibbald, Mark J.J.B.; Quax, Wim J.

    2015-01-01

    Creating novel biosynthetic pathways and modulating the synthesis of important compounds are one of the hallmarks of synthetic biology. Understanding the key parameters controlling the flux of chemicals throughout a metabolic pathway is one of the challenges ahead. Isoprenoids are the most

  5. Monitoring- and Evaluation Program Near Shore Wind farm (MEP-NSW): Fish community

    NARCIS (Netherlands)

    Hal, van R.; Couperus, A.S.; Fassler, S.M.M.; Gastauer, S.; Griffioen, B.; Hintzen, N.T.; Teal, L.R.; Keeken, van O.A.; Winter, H.V.

    2012-01-01

    In 2006, the first Dutch offshore wind farm was built 10-18 km from the shore of Egmond aan Zee by a joint venture of Nuon and Shell Windenergy. A Monitoring and Evaluation Program accompanied the plans for the construction and exploitation of this farm. The program contained plans for the monitorin

  6. New insight in isoprenoids biosynthesis process and future prospects for drug designing in Plasmodium

    Directory of Open Access Journals (Sweden)

    Gagandeep Singh Saggu

    2016-09-01

    Full Text Available The MEP (Methyl Erythritol Phosphate isoprenoids biosynthesis pathway is an attractive drug target to combat malaria, due to its uniqueness and indispensability for the parasite. It is functional in the apicoplast of Plasmodium and its products get transported to the cytoplasm, where they participate in glycoprotein synthesis, electron transport chain, tRNA modification and several other biological processes. Several compounds have been tested against the enzymes involved in this pathway and amongst them Fosmidomycin, targeted against IspC (DXP reductoisomerase enzyme and MMV008138 targeted against IspD enzyme have shown good anti-malarial activity in parasite cultures. Fosmidomycin is now-a-days prescribed clinically, however, less absorption, shorter half-life, and toxicity at higher doses, limits its use as an anti-malarial. The potential of other enzymes of the pathway as candidate drug targets has also been determined. This review details the various drug molecules tested against these targets with special emphasis to Plasmodium. We corroborate that MEP pathway functional within the apicoplast of Plasmodium is a major drug target, especially during erythrocytic stages. However, the major bottlenecks, bioavailability and toxicity of the new molecules needs to be addressed, before considering any new molecule as a potent antimalarial.

  7. Characterization of the Arabidopsis clb6 mutant illustrates the importance of posttranscriptional regulation of the methyl-D-erythritol 4-phosphate pathway.

    Science.gov (United States)

    Guevara-García, Arturo; San Román, Carolina; Arroyo, Analilia; Cortés, María Elena; de la Luz Gutiérrez-Nava, María; León, Patricia

    2005-02-01

    The biosynthesis of isopentenyl diphosphate and dimethylallyl diphosphate, the two building blocks for isoprenoid biosynthesis, occurs by two independent pathways in plants. The mevalonic pathway operates in the cytoplasm, and the methyl-d-erythritol 4-phosphate (MEP) pathway operates in plastids. Plastidic isoprenoids play essential roles in plant growth and development. Plants must regulate the biosynthesis of isoprenoids to fulfill metabolic requirements in specific tissues and developmental conditions. The regulatory events that modulate the plant MEP pathway are not well understood. In this article, we demonstrate that the CHLOROPLAST BIOGENESIS6 (CLB6) gene, previously shown to be required for chloroplast development, encodes 1-hydroxy-2-methyl-butenyl 4-diphosphate reductase, the last-acting enzyme of the MEP pathway. Comparative analysis of the expression levels of all MEP pathway gene transcripts and proteins in the clb6-1 mutant background revealed that posttranscriptional control modulates the levels of different proteins in this central pathway. Posttranscriptional regulation was also found during seedling development and during fosmidomycin inhibition of the pathway. Our results show that the first enzyme of the pathway, 1-deoxy-d-xylulose 5-phosphate synthase, is feedback regulated in response to the interruption of the flow of metabolites through the MEP pathway.

  8. Unraveling Massive Crocins Transport and Accumulation through Proteome and Microscopy Tools during the Development of Saffron Stigma

    Directory of Open Access Journals (Sweden)

    Lourdes Gómez-Gómez

    2017-01-01

    Full Text Available Crocins, the glucosides of crocetin, are present at high concentrations in saffron stigmas and accumulate in the vacuole. However, the biogenesis of the saffron chromoplast, the changes during the development of the stigma and the transport of crocins to the vacuole, are processes that remain poorly understood. We studied the process of chromoplast differentiation in saffron throughout stigma development by means of transmission electron microscopy. Our results provided an overview of a massive transport of crocins to the vacuole in the later developmental stages, when electron dense drops of a much greater size than plastoglobules (here defined “crocinoplast” were observed in the chromoplast, connected to the vacuole with a subsequent transfer of these large globules inside the vacuole. A proteome analysis of chromoplasts from saffron stigma allowed the identification of several well-known plastid proteins and new candidates involved in crocetin metabolism. Furthermore, expressions throughout five developmental stages of candidate genes responsible for carotenoid and apocarotenoid biogenesis, crocins transport to the vacuole and starch metabolism were analyzed. Correlation matrices and networks were exploited to identify a series of transcripts highly associated to crocetin (such as 1-Deoxy-d-xylulose 5-phosphate synthase (DXS, 1-Deoxy-d-xylulose 5-phosphate reductoisomerase (DXR, carotenoid isomerase (CRTISO, Crocetin glucosyltransferase 2 (UGT2, etc. and crocin (e.g., ζ-carotene desaturase (ZDS and plastid-lipid-associated proteins (PLAP2 accumulation; in addition, candidate aldehyde dehydrogenase (ADH genes were highlighted.

  9. Unraveling Massive Crocins Transport and Accumulation through Proteome and Microscopy Tools during the Development of Saffron Stigma

    Science.gov (United States)

    Gómez-Gómez, Lourdes; Parra-Vega, Verónica; Rivas-Sendra, Alba; Seguí-Simarro, Jose M.; Molina, Rosa Victoria; Pallotti, Claudia; Rubio-Moraga, Ángela; Diretto, Gianfranco; Prieto, Alicia; Ahrazem, Oussama

    2017-01-01

    Crocins, the glucosides of crocetin, are present at high concentrations in saffron stigmas and accumulate in the vacuole. However, the biogenesis of the saffron chromoplast, the changes during the development of the stigma and the transport of crocins to the vacuole, are processes that remain poorly understood. We studied the process of chromoplast differentiation in saffron throughout stigma development by means of transmission electron microscopy. Our results provided an overview of a massive transport of crocins to the vacuole in the later developmental stages, when electron dense drops of a much greater size than plastoglobules (here defined “crocinoplast”) were observed in the chromoplast, connected to the vacuole with a subsequent transfer of these large globules inside the vacuole. A proteome analysis of chromoplasts from saffron stigma allowed the identification of several well-known plastid proteins and new candidates involved in crocetin metabolism. Furthermore, expressions throughout five developmental stages of candidate genes responsible for carotenoid and apocarotenoid biogenesis, crocins transport to the vacuole and starch metabolism were analyzed. Correlation matrices and networks were exploited to identify a series of transcripts highly associated to crocetin (such as 1-Deoxy-d-xylulose 5-phosphate synthase (DXS), 1-Deoxy-d-xylulose 5-phosphate reductoisomerase (DXR), carotenoid isomerase (CRTISO), Crocetin glucosyltransferase 2 (UGT2), etc.) and crocin (e.g., ζ-carotene desaturase (ZDS) and plastid-lipid-associated proteins (PLAP2)) accumulation; in addition, candidate aldehyde dehydrogenase (ADH) genes were highlighted. PMID:28045431

  10. Synthesis and enzymic activity of various substituted pyrazolo[1,5-a]-1,3,5-triazines as adenosine cyclic 3',5'-phosphate phosphodiesterase inhibitors.

    Science.gov (United States)

    Senga, K; O'Brien, D E; Scholten, M B; Novinson, T; Miller, J P; Robins, R K

    1982-03-01

    A series of various pyrazolo[1,5-a]-1,3,5-triazines have been prepared and studied as inhibitors of cAMP phosphodiesterase isolated from bovine brain, bovine heart, and rabbit lung. A number of compounds were found to be superior to theophylline. 2-Ethyl-7-phenylpyrazolo[1,5-a]-1,3,5-triazine (35) was found to be 97 times more potent than theophylline as an inhibitor of bovine brain PDE. 8-Bromo-2,4-dimethyl-7-phenylpyrazolo[1,5-a]-1,3,5-triazine (52) showed alpha lung = 40 compared to alpha heart = 3.0. Thus, various substituents could increase or decrease the inhibition relative to the type and source of tissue from which the PDE was isolated. The most active compound was 8-bromo-4-(diethylamino)-7-phenylpyrazolo[1,3-a]-1,3,5-triazine (25), which was 185 times more potent than theophylline as an inhibitor of PDE isolated from rabbit lung. The stepwise synthesis via ring-closure procedures of requisite pyrazole intermediates, followed by electrophilic substitution in the pyrazole ring and/or nucleophilic substitution in the 1,3,5-triazine moiety, resulted in the various pyrazolo[1,5-a]1,3,5-triazines listed in Tables I and II. Structure-activity relationships are reviewed.

  11. An insight into the sequential, structural and phylogenetic properties of banana 1-aminocyclopropane-1-carboxylate synthase 1 and study of its interaction with pyridoxal-5'-phosphate and aminoethoxyvinylglycine

    Indian Academy of Sciences (India)

    Swarup Roy Choudhury; Sanjay Kumar Singh; Sujit Roy; Dibyendu N Sengupta

    2010-06-01

    In banana, ethylene production for ripening is accompanied by a dramatic increase in 1-aminocyclopropane-1-carboxylate (ACC) content, transcript level of Musa acuminata ACC synthase 1 (MA-ACS1) and the enzymatic activity of ACC synthase 1 at the onset of the climacteric period. MA-ACS1 catalyses the conversion of -adenosyl-L-methionine (SAM) to ACC, the key regulatory step in ethylene biosynthesis. Multiple sequence alignments of 1-aminocyclopropane-1-carboxylate synthase (ACS) amino acid sequences based on database searches have indicated that MA-ACS1 is a highly conserved protein across the plant kingdom. This report describes an in silico analysis to provide the first important insightful information about the sequential, structural and phylogenetic characteristics of MA-ACS1. The three-dimensional structure of MA-ACS1, constructed based on homology modelling, in combination with the available data enabled a comparative mechanistic analysis of MA-ACS1 to explain the catalytic roles of the conserved and non-conserved active site residues. We have further demonstrated that, as in apple and tomato, banana-ACS1 (MA-ACS1) forms a homodimer and a complex with cofactor pyridoxal-5′-phosphate (PLP) and inhibitor aminoethoxyvinylglycine (AVG). We have also predicted that the residues from the PLP-binding pocket, essential for ligand binding, are mostly conserved across the MA-ACS1 structure and the competitive inhibitor AVG binds at a location adjacent to PLP.

  12. Differential incorporation of 1-deoxy-D-xylulose into (3S)-linalool and geraniol in grape berry exocarp and mesocarp.

    Science.gov (United States)

    Luan, Fang; Wüst, Matthias

    2002-07-01

    In vivo feeding experiments with [5,5-(2)H(2)]mevalonic acid lactone (MVL) and [5,5-(2)H(2)]-1-deoxy-D-xylulose (DOX) indicate that the novel mevalonate-independent 1-deoxy- D-xylulose 5-phosphate/2C-methyl- D-erythritol 4-phosphate (DOXP/MEP) pathway is the dominant metabolic route for monoterpene biosynthesis in grape berry exocarp and mesocarp and in grape leaves. The highly uneven distribution of the monoterpene alcohols (3S)-linalool and geraniol between leaves, berry exocarp and berry mesocarp can be attributed to a compartmentation of monoterpene metabolism. In grape berries incorporation of [5,5-(2)H(2)]-DOX into geraniol is mainly restricted to the exocarp, whereas (3S)-linalool biosynthesis can be detected in exocarp as well as in mesocarp tissue. The results demonstrate that grape berries exhibit an autonomic monoterpene biosynthesis via the novel DOXP/MEP route throughout the ripening process.

  13. Recovery of TES-MEPs During Surgical Decompression of the Spine : A Case Series of Eight Patients

    NARCIS (Netherlands)

    Visser, Jetze; Verra, Wiebe C.; Kuijlen, Jos M.; Horsting, Philip P.; Journee, Henricus L.

    2014-01-01

    Purpose: This study aimed to illustrate the recovery of transcranial electrical stimulation motor evoked potentials during surgical decompression of the spinal cord in patients with impaired motor function preoperatively. Specific attention was paid to the duration of neurologic symptoms before surg

  14. Caracterización de las combustiones anómalas producidas en un MEP-H2

    OpenAIRE

    Villar Olano, Santiago del

    2014-01-01

    El objetivo de este trabajo es analizar el proceso de combustión en un motor de combustión interna alternativo, MCIA, de encendido provocado y usando hidrógeno como combustible. Un óptimo proceso de combustión es la llave que abre la puerta a un idóneo funcionamiento del motor. Por tanto, analizaremos los diversos fenómenos, combustiones anómalas, que se producen en el proceso de combustión debido al aumento del dosado. En concreto estos sucesos limitan el rendimiento máximo cr...

  15. Guangxi Nanguo Copper’s150,000 t/a Copper Smelting Project was Approval by the MEP

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    <正>In the middle of August,the environmental impact report for 150,000 t/a copper smelting project of Guangxi Nanguo Copper Industry Co.,Ltd received formal approval from the Ministry of Environmental Protection,signaling that this project’s environmental impact

  16. Up-to-Date on Preventive Care Services Under Affordable Care Act: A Trend Analysis From MEPS 2007-2014.

    Science.gov (United States)

    Hong, Young-Rock; Jo, Ara; Mainous, Arch G

    2017-08-01

    The utilization of preventive care services has been less than optimal. As part of an effort to address this, the Affordable Care Act (ACA) mandated that private health insurance plans cover evidence-based preventive services. To evaluate whether the provisions of ACA have increased being up-to-date on recommended preventive care services among privately insured individuals aged 18-64. Multivariate linear regression models were used to examine trends in prevalence of being up-to-date on selected preventive services, diagnosis of health conditions, and health expenditures between pre-ACA (2007-2010) and post-ACA (2011-2014). Adjusted difference-in-difference analyses were used to estimate changes in those outcomes in the privately insured that differed from changes in the uninsured (control group). After the passage of ACA, up-to-date rates of routine checkup (2.7%; 95% confidence interval, 0.8%-4.7%; P=0.007) and flu vaccination (5.9%; 95% confidence interval, 4.2%-7.6%; Pup-to-date on selected preventive care services. Additional efforts may be required to take full advantage of the elimination of cost-sharing under the ACA.

  17. Organ- and Growing Stage-Specific Expression of Solanesol Biosynthesis Genes in Nicotiana tabacum Reveals Their Association with Solanesol Content

    Directory of Open Access Journals (Sweden)

    Ning Yan

    2016-11-01

    Full Text Available Solanesol is a noncyclic terpene alcohol that is composed of nine isoprene units and mainly accumulates in solanaceous plants, especially tobacco (Nicotiana tabacum L.. In the present study, RNA-seq analyses of tobacco leaves, stems, and roots were used to identify putative solanesol biosynthesis genes. Six 1-deoxy-d-xylulose 5-phosphate synthase (DXS, two 1-deoxy-d-xylulose 5-phosphate reductoisomerase (DXR, two 2-C-methyl-d-erythritol 4-phosphate cytidylyltransferase (IspD, four 4-diphosphocytidyl-2-C-methyl-d-erythritol kinase (IspE, two 2-C-methyl-d-erythritol 2,4-cyclo-diphosphate synthase (IspF, four 1-hydroxy-2-methyl-2-(E-butenyl 4-diphosphate synthase (IspG, two 1-hydroxy-2-methyl-2-(E-butenyl 4-diphosphate reductase (IspH, six isopentenyl diphosphate isomerase (IPI, and two solanesyl diphosphate synthase (SPS candidate genes were identified in the solanesol biosynthetic pathway. Furthermore, the two N. tabacum SPS proteins (NtSPS1 and NtSPS2, which possessed two conserved aspartate-rich DDxxD domains, were highly homologous with SPS enzymes from other solanaceous plant species. In addition, the solanesol contents of three organs and of leaves from four growing stages of tobacco plants corresponded with the distribution of chlorophyll. Our findings provide a comprehensive evaluation of the correlation between the expression of different biosynthesis genes and the accumulation of solanesol, thus providing valuable insight into the regulation of solanesol biosynthesis in tobacco.

  18. Predicted essential proteins ofPlasmodium falciparum for potential drug targets

    Institute of Scientific and Technical Information of China (English)

    Qing-Feng He; Li Deng; Qin-Ying Xu; Zheng Shao

    2012-01-01

    ABSTRACT Objective:To identify novel drug targets for treatment ofPlasmodium falciparum.Methods:LocalBLASTP were used to find the proteins non-homologous to human essential proteins as novel drug targets. Functional domains of novel drug targets were identified by InterPro and Pfam,3D structures of potential drug targets were predicated by theSWISS-MODELworkspace. Ligands and ligand-binding sites of the proteins were searched byEf-seek.Results:Three essential proteins were identified that might be considered as potential drug targets.AAN37254.1 belonged to1-deoxy-D-xylulose5-phosphate reductoisomerase,CAD50499.1 belonged to chorismate synthase,CAD51220.1 belonged toFAD binging3 family, but the function of CAD51220.1 was unknown. The3D structures, ligands and ligand-binding sites ofAAN37254.1 andCAD50499.1 were successfully predicated.Conclusions:Two of these potential drug targets are key enzymes in2-C-methyl-d-erythritol4-phosphate pathway and shikimate pathway, which are absent in humans, so these two essential proteins are good potential drug targets. The function and3D structures ofCAD50499.1 is still unknown, it still need further study.

  19. Expression of carotenoid biosynthetic pathway genes and changes in carotenoids during ripening in tomato (Lycopersicon esculentum).

    Science.gov (United States)

    Namitha, Kanakapura Krishnamurthy; Archana, Surya Narayana; Negi, Pradeep Singh

    2011-04-01

    To study the expression pattern of carotenoid biosynthetic pathway genes, changes in their expression at different stages of maturity in tomato fruit (cv. Arka Ahuti) were investigated. The genes regulating carotenoid production were quantified by a dot blot method using a DIG (dioxigenin) labelling and detection kit. The results revealed that there was an increase in the levels of upstream genes of the carotenoid biosynthetic pathway such as 1-deoxy-d-xylulose-5-phosphate reductoisomerase (DXR), 4-hydroxy-3-methyl-but-2-enyl diphosphate reductase (Lyt B), phytoene synthase (PSY), phytoene desaturase (PDS) and ζ-carotene desaturase (ZDS) by 2-4 fold at the breaker stage as compared to leaf. The lycopene and β-carotene content was analyzed by HPLC at different stages of maturity. The lycopene (15.33 ± 0.24 mg per 100 g) and β-carotene (10.37 ± 0.46 mg per 100 g) content were found to be highest at 5 days post-breaker and 10 days post-breaker stage, respectively. The lycopene accumulation pattern also coincided with the color values at different stages of maturity. These studies may provide insight into devising gene-based strategies for enhancing carotenoid accumulation in tomato fruits.

  20. Metabolic engineering by plastid transformation as a strategy to modulate isoprenoid yield in plants.

    Science.gov (United States)

    Hasunuma, Tomohisa; Kondo, Akihiko; Miyake, Chikahiro

    2010-01-01

    Plants synthesize a large number of isoprenoid compounds that have diverse structures and functions. All isoprenoids are synthesized through consecutive condensation of five-carbon precursors, isopentenyl diphosphate (IPP) and its allyl isomer dimethylallyl diphosphate (DMAPP). With recent success in the cloning of genes that encode the enzymes of isoprenoid biosynthesis, genetic engineering strategies for the improvement of plant isoprenoid metabolism have emerged. Plastid transformation technology offers attractive features in plant genetic engineering. It has many advantages over nuclear genome transformation: high-level foreign protein expression, no need for a transit peptide, absence of gene silencing, and convenient transgene stacking in operons. We demonstrated that this technology is a remarkable tool for the production of isoprenoids in plants through metabolic engineering. The expression of bacterial genes encoding CrtW (beta-carotene ketolase) and CrtZ (beta-carotene hydroxylase) or cyanobacterial genes encoding DXR (1-deoxy-D-xylulose-5-phosphate reductoisomerase) in the plastid genome leads to alteration in isoprenoid content of tobacco leaves.

  1. Transition-state-guided drug design for treatment of parasitic neglected tropical diseases.

    Science.gov (United States)

    Murkin, A S; Moynihan, M M

    2014-01-01

    Many of the deadliest neglected tropical diseases are caused by protozoan and helminthic parasites. These organisms have evolved several enzymes to exploit their host's metabolic resources and evade immune responses. Because these essential proteins are absent in humans, they are targets for antiparasitic drug development. Despite decades of investigation, no therapy has been successful in the eradication of these diseases, so new approaches are desired. Chemically stable analogues of the transition states of enzymatic reactions are often potent inhibitors, and several examples of clinically effective compounds are known for other diseases. The design of transition-state analogues is aided by structural models of the transition state, which are obtained by complementing experimental measurement of kinetic isotope effects with theoretical calculations. Such transition-state-guided inhibitor design has been demonstrated for human, bovine, malarial, and trypanosomal enzymes of the purine salvage pathway, including purine nucleoside phosphorylase, nucleoside hydrolases, and adenosine deaminase. Cysteine proteases, trans-sialidase, 1-deoxy-d-xylulose-5-phosphate reductoisomerase, and trypanothione synthetase are presented as additional candidates for application of transition-state analysis with the goal of identifying new leads for the treatment of parasitic neglected tropical diseases.

  2. Proteomics analysis of UV-irradiated Lonicera japonica Thunb. with bioactive metabolites enhancement.

    Science.gov (United States)

    Zhang, Lin; Li, Ximin; Zheng, Wen; Fu, Zhirong; Li, Wenting; Ma, Luyu; Li, Ke; Sun, Lianli; Tian, Jingkui

    2013-12-01

    A previous study showed that the contents of caffeoylquinic acids and iridoids, the major bioactive components in the postharvest Lonicera japonica Thunb., were induced by enhanced ultraviolet (UV)-A or UV-B irradiation. To clarify the UV-responsive key enzymes in the bioactive metabolites biosynthetic pathway and the related plant defense mechanism in L. japonica, 2DE in combination with MALDI-TOF/TOF MS was employed. Seventy-five out of 196 differential proteins were positively identified. Based on the functions, these proteins were grouped into nine categories, covering a wide range of molecular processes including the secondary metabolites (caffeoylquinic acids and iridoids) biosynthetic-related proteins, photosynthesis, carbohydrate and energy metabolism, stress, DNA, transport-related proteins, lipid metabolism, amino acid metabolism, cell wall. Of note is the increasing expression of 1-deoxy-d-xylulose 5-phosphate reductoisomerase and 5-enol-pyruvylshikimate-phosphate synthase, which was crucial to supply more precursor for the secondary metabolites including caffeoylquinic acids and iridoids. Thus, this study provides both the clues at the protein level for the increase of the two bioactive components upon UV irradiation and the profile of UV-responsive proteins in L. japonica.

  3. Molecular cloning and characterisation of two calmodulin isoforms of the Madagascar periwinkle Catharanthus roseus.

    Science.gov (United States)

    Poutrain, P; Guirimand, G; Mahroug, S; Burlat, V; Melin, C; Ginis, O; Oudin, A; Giglioli-Guivarc'h, N; Pichon, O; Courdavault, V

    2011-01-01

    Involvement of Ca(2+) signalling in regulation of the biosynthesis of monoterpene indole alkaloids (MIA) in Catharanthus roseus has been extensively studied in recent years, albeit no protein of this signalling pathway has been isolated. Using a PCR strategy, two C. roseus cDNAs encoding distinct calmodulin (CAM) isoforms were cloned and named CAM1 and CAM2. The deduced 149 amino acid sequences possess four Ca(2+) binding domains and exhibit a close identity with Arabidopsis CAM isoforms (>91%). The ability of CAM1 and CAM2 to bind Ca(2+) was demonstrated following expression of the corresponding recombinant proteins. Furthermore, transient expression of CAM1-GFP and CAM2-GFP in C. roseus cells showed a typical nucleo-cytoplasm localisation of both CAMs, in agreement with the wide distribution of CAM target proteins. Using RNA blot analysis, we showed that CAM1 and CAM2 genes had a broad pattern of expression in C. roseus organs and are constitutively expressed during a C. roseus cell culture cycle, with a slight inhibitory effect of auxin for CAM1. Using RNA in situ hybridisation, we also detected CAM1 and CAM2 mRNA in the vascular bundle region of young seedling cotyledons. Finally, using specific inhibitors, we also showed that CAMs are required for MIA biosynthesis in C. roseus cells by acting on regulation of expression of genes encoding enzymes that catalyse early steps of MIA biosynthesis, such as 1-deoxy-d-xylulose 5-phosphate reductoisomerase and geraniol 10-hydroxylase.

  4. Molecular cloning of allelopathy related genes and their relation to HHO in Eupatorium adenophorum.

    Science.gov (United States)

    Guo, Huiming; Pei, Xixiang; Wan, Fanghao; Cheng, Hongmei

    2011-10-01

    In this study, conserved sequence regions of HMGR, DXR, and CHS (encoding 3-hydroxy-3-methylglutaryl-CoA reductase, 1-deoxyxylulose-5-phosphate reductoisomerase and chalcone synthase, respectively) were amplified by reverse transcriptase (RT)-PCR from Eupatorium adenophorum. Quantitative real-time PCR showed that the expression of CHS was related to the level of HHO, an allelochemical isolated from E. adenophorum. Semi-quantitative RT-PCR showed that there was no significant difference in expression of genes among three different tissues, except for CHS. Southern blotting indicated that at least three CHS genes are present in the E. adenophorum genome. A full-length cDNA from CHS genes (named EaCHS1, GenBank ID: FJ913888) was cloned. The 1,455 bp cDNA contained an open reading frame (1,206 bp) encoding a protein of 401 amino acids. Preliminary bioinformatics analysis of EaCHS1 revealed that EaCHS1 was a member of CHS family, the subcellular localization predicted that EaCHS1 was a cytoplasmic protein. To the best of our knowledge, this is the first report of conserved sequences of these genes and of a full-length EaCHS1 gene in E. adenophorum. The results indicated that CHS gene is related to allelopathy of E. adenophorum.

  5. The Plastidial 2-C-Methyl-d-Erythritol 4-Phosphate Pathway Provides the Isoprenyl Moiety for Protein Geranylgeranylation in Tobacco BY-2 Cells[C][W

    Science.gov (United States)

    Gerber, Esther; Hemmerlin, Andréa; Hartmann, Michael; Heintz, Dimitri; Hartmann, Marie-Andrée; Mutterer, Jérôme; Rodríguez-Concepción, Manuel; Boronat, Albert; Van Dorsselaer, Alain; Rohmer, Michel; Crowell, Dring N.; Bach, Thomas J.

    2009-01-01

    Protein farnesylation and geranylgeranylation are important posttranslational modifications in eukaryotic cells. We visualized in transformed Nicotiana tabacum Bright Yellow-2 (BY-2) cells the geranylgeranylation and plasma membrane localization of GFP-BD-CVIL, which consists of green fluorescent protein (GFP) fused to the C-terminal polybasic domain (BD) and CVIL isoprenylation motif from the Oryza sativa calmodulin, CaM61. Treatment with fosmidomycin (Fos) or oxoclomazone (OC), inhibitors of the plastidial 2-C-methyl-d-erythritol 4-phosphate (MEP) pathway, caused mislocalization of the protein to the nucleus, whereas treatment with mevinolin, an inhibitor of the cytosolic mevalonate pathway, did not. The nuclear localization of GFP-BD-CVIL in the presence of MEP pathway inhibitors was completely reversed by all-trans-geranylgeraniol (GGol). Furthermore, 1-deoxy-d-xylulose (DX) reversed the effects of OC, but not Fos, consistent with the hypothesis that OC blocks 1-deoxy-d-xylulose 5-phosphate synthesis, whereas Fos inhibits its conversion to 2-C-methyl-d-erythritol 4-phosphate. By contrast, GGol and DX did not rescue the nuclear mislocalization of GFP-BD-CVIL in the presence of a protein geranylgeranyltransferase type 1 inhibitor. Thus, the MEP pathway has an essential role in geranylgeranyl diphosphate (GGPP) biosynthesis and protein geranylgeranylation in BY-2 cells. GFP-BD-CVIL is a versatile tool for identifying pharmaceuticals and herbicides that interfere either with GGPP biosynthesis or with protein geranylgeranylation. PMID:19136647

  6. Expression of Bombyx mori Pyridoxine-5'-phosphate Oxidase in E. coli and Assay of Enzymological Characters%家蚕磷酸吡哆醇氧化酶在E.coli中的表达及酶学特征研究

    Institute of Scientific and Technical Information of China (English)

    王振; 张剑韵; 黄龙全

    2010-01-01

    磷酸吡哆醇氧化酶(pyridoxine-5′-phosphate oxidase, PNPO)是维生素B6(VB6)代谢的关键酶.采用重组质粒pET32a(+)-PNPO原核表达家蚕(Bombyx mori)PNPO,经Ni2+亲和层析纯化后对其基本酶学性质进行分析.结果表明,纯化后的家蚕重组PNPO经SDS-PAGE鉴定为单一条带,比活力为529.81 nmol/(min·mg)蛋白,纯化倍数为7.1倍;该酶的最适反应温度为40 ℃,在50 ℃以下稳定;在pH 8.0~9.0之间酶活力最高,pH 6.0~10.0之间活力保持稳定.该结果有助于进一步开展家蚕PNPO的催化作用和表达调控机制的研究.

  7. 高效液相色谱分析法测定磷酸-5'-吡哆醛质量分数%Determination of Pyridoxal-5'-phosphate by High Performance Liquid Chromatography

    Institute of Scientific and Technical Information of China (English)

    胡鸣; 凌芳; 郑琦; 陈浩云; 干海平

    2016-01-01

    建立了磷酸-5'-吡哆醛的高效液相色谱定量检测方法.实验采用C18反相色谱柱(5μm,250 mm×4.6mm);流动相为乙腈-水,二者体积比为(10~30):(70~90);流速为1.0 mL/min;柱温为30℃;检测波长为388 nm;进样量为10.0 μL(将测定主成分质量分数的进样样品用水溶解并稀释成0.2 g/L).实验结果表明,磷酸-5'-吡哆醛的线性方程为y=7575.6x+4801.8,r=0.99995,检出限为0.2 g/L.

  8. 磷酸吡哆醛补救途径两个关键酶的研究进展%Research advance in two key enzymes involved in the pyridoxal 5'-phosphate salvage pathway

    Institute of Scientific and Technical Information of China (English)

    黄龙全; 张剑韵

    2015-01-01

    维生素B6(VB6)包括6个可相互转换的吡啶衍生物.其中,磷酸吡哆醛(PLP)作为140多种细胞酶的辅酶,在生物体内发挥重要作用.动物从食物中获得VB6,通过由吡哆醛激酶和磷酸吡哆醇氧化酶构成的补救途径合成PLP.PLP依赖酶的正常功能乃至人体最佳健康状态,依赖于细胞中PLP的平衡供给.然而,就PLP的动态平衡和调节机制以及PLP合成后的转移机制而言,目前还知之甚少,是一个富有挑战性的研究领域.为此,综述PLP补救途径两个关键酶的研究进展.

  9. Alanyl-lipid synthesis with microwave-induced organic reaction and its interaction with pyridoxal -5-phosphate on lipid surface%丙氨酰类脂的微波合成及其功能

    Institute of Scientific and Technical Information of China (English)

    石太德; 刘宝全; 王剑锋; 范圣第

    2009-01-01

    利用微波合成仪制备双十六烷基胺,通过DCC交联反应,得到叔丁氧甲酰丙氨酰双十六烷基胺,再通过酸水解制备出丙氨酰类脂.利用丙氨酰类脂的季铵盐衍生物(丙氨酰肽脂质)构建人工二分子膜,研究了磷酸吡哆醛(PLP)与丙氨酰类脂的相互作用.紫外-可见光谱检测发现,在330 nm 及415 nm 处有亚胺的特征吸收峰,表明PLP可以识别人工二分子膜上的丙氨酰类脂,丙氨酰类脂可以用作人工细胞信号转导的受体.

  10. 5'-磷酸吡哆醛影响血清丙氨酸氨基转移酶测定的研究%Effection of Pyridoxal -5'-phosphate on Determination of Alanine Aminotransferase activities

    Institute of Scientific and Technical Information of China (English)

    张宗彬; 鲍杰; 陈龙泉; 李传胜; 马洪波

    2007-01-01

    目的 研究丙氨酸氨基转移酶(Alanine Aminotraasferase,ALT)检测试剂中5'-磷酸吡哆醛(Pyrldoxal-5'-phos-phate,PLP)的添加对血清ALT活力测定的影响.方法 按IFCC推荐方法,自配ALT检测试剂(含PLP)和相应不添加PLP的检测试剂,分别用这两种试剂测定相同的新鲜临床标本,并对检测结果进行统计学比较.结果 使用含PLP的IFCC配方试剂较不含PLP试剂的检测结果明显增高.结论 健康人群和不同疾病人群由于个体差异,体内PLP含量不一,各组数据表明不含PLP配方试剂较IFCC配方检测结果明显偏低,因此两种配方的检测结果不能通过简单系数实现转换.

  11. The 2-C-methylerythritol 4-phosphate pathway in melon is regulated by specialized isoforms for the first and last steps.

    Science.gov (United States)

    Saladié, Montserrat; Wright, Louwrance P; Garcia-Mas, Jordi; Rodriguez-Concepcion, Manuel; Phillips, Michael A

    2014-09-01

    The 2-C-methyl-d-erythritol-4-phosphate (MEP) pathway provides the precursors for the biosynthesis of plastidial isoprenoids, which include the carotenoid pigments of many fruits. We have analysed the genes encoding the seven enzymes of the MEP pathway in melon (Cucumis melo L.) and determined that the first one, 1-deoxyxylulose 5-phosphate synthase (DXS), and the last one, 1-hydroxy-2-methyl-2-(E)-butenyl 4-diphosphate reductase (HDR), are represented in the genome as a small gene family and paralogous pair, respectively. In the case of DXS, three genes encode functional DXS activities which fall into previously established type I (CmDXS1) and II (CmDXS2a and CmDXS2b) categories, while a fourth DXS-like gene belonging to the type III group did not encode a protein with DXS activity. Their expression patterns and phylogenies suggest that CmDXS1 is functionally specialized for developmental and photosynthetic processes, while CmDXS2a and CmDXS2b are induced in flowers and ripening fruit of orange- (but not white-) fleshed varieties, coinciding with β-carotene accumulation. This is the first instance connecting type II DXS genes to specialized isoprenoid biosynthesis in the fruit of an agronomically important species. Two HDR paralogues were shown to encode functional enzymes, although only CmHDR1 was highly expressed in the tissues and developmental stages tested. Phylogenetic analysis showed that in cucurbits such as melon, these HDR paralogues probably arose through individual gene duplications in a common angiosperm ancestor, mimicking a prior division in gymnosperms, while other flowering plants, including apple, soy, canola, and poplar, acquired HDR duplicates recently as homoeologues through large-scale genome duplications. We report the influence of gene duplication history on the regulation of the MEP pathway in melon and the role of specialized MEP-pathway isoforms in providing precursors for β-carotene production in orange-fleshed melon varieties.

  12. AcEST: BP920759 [AcEST

    Lifescience Database Archive (English)

    Full Text Available nit a OS=Rubrobacter xylan... 33 0.46 sp|Q11I83|ILVC_MESSB Ketol-acid reductoisomerase OS=Mesorhizobiu... 30...YPVTSNISFTATLALFTFVLTQYEGVRRNGL 148 >sp|Q11I83|ILVC_MESSB Ketol-acid reductoisomerase OS=Mesorhizobium sp. (

  13. A combination of whey protein and potassium bicarbonate supplements during head-down-tilt bed rest: Presentation of a multidisciplinary randomized controlled trial (MEP study)

    Science.gov (United States)

    Buehlmeier, Judith; Mulder, Edwin; Noppe, Alexandra; Frings-Meuthen, Petra; Angerer, Oliver; Rudwill, Floriane; Biolo, Gianni; Smith, Scott M.; Blanc, Stéphane; Heer, Martina

    2014-02-01

    Inactivity, as it appears during space flight and in bed rest, induces reduction of lean body and bone mass, glucose intolerance, and weakening of the cardiovascular system. Increased protein intake, whey protein in particular, has been proposed to counteract some of these effects, but has also been associated with negative effects on bone, likely caused by a correspondingly high ratio of acid to alkali precursors in the diet.

  14. LOS TEXTOS LITERARIOS QUE ASIGNA EL MEP PARA EL TERCER CICLO DE LA EDUCACIÓN GENERAL BÁSICA EN COSTA RICA: ALGUNAS REFLEXIONES AL RESPECTO

    Directory of Open Access Journals (Sweden)

    Grettel Arias Orozco

    2016-01-01

    Full Text Available En el presente artículo se detallan y analizan las principales modificaciones que presenta la lista de lecturas obligatorias propuesta en el año 2010 e implementada por el Ministerio de Educación Pública a partir del año 2011, en el Tercer Ciclo de la Educación General Básica costarricense. El estudio fue realizado a partir de la búsqueda bibliográfica de revistas especializadas, tesis de grado, libros, los Planes de Estudios de Español del 2005 y del año 2009, la lista de lecturas obligatorias implementada en el 2011, así como también gracias a entrevistas a especialistas en el área de la educación costarricense. Se concluye que las principales modificaciones responden a la dosificación, la categorización y la flexibilidad del listado de lecturas, pues la cantidad de textos y los géneros literarios que se estudian por nivel se modifican, así como también ahora se le brinda una gama de opciones al docente para que elija qué leer con su grupo estudiantil; no obstante, también se evidencia que ninguno de estos cambios ha sido debidamente fundamentado en la nueva propuesta. Finalmente, se destaca la incorporación de un corpus significativo de textos literarios que hacen referencia al personaje del presidente Juan Mora Porras, cuyo fin se vislumbra de carácter identitario e ideológico, pues su propósito es contrarrestar el desencanto político que ha aumentado en los últimos años e instaurarse como el nuevo referente del héroe nacional.

  15. Enhanced production of steviol glycosides in mycorrhizal plants: a concerted effect of arbuscular mycorrhizal symbiosis on transcription of biosynthetic genes.

    Science.gov (United States)

    Mandal, Shantanu; Upadhyay, Shivangi; Singh, Ved Pal; Kapoor, Rupam

    2015-04-01

    Stevia rebaudiana (Bertoni) produces steviol glycosides (SGs)--stevioside (stev) and rebaudioside-A (reb-A) that are valued as low calorie sweeteners. Inoculation with arbuscular mycorrhizal fungi (AMF) augments SGs production, though the effect of this interaction on SGs biosynthesis has not been studied at molecular level. In this study transcription profiles of eleven key genes grouped under three stages of the SGs biosynthesis pathway were compared. The transcript analysis showed upregulation of genes encoding 2-C-methyl-D-erythritol-4-phosphate (MEP) pathway enzymes viz.,1-deoxy-D-xylulose 5-phospate synthase (DXS), 1-deoxy-D-xylulose 5-phospate reductoisomerase (DXR) and 2-C-methyl-D-erytrithol 2,4-cyclodiphosphate synthase (MDS) in mycorrhizal (M) plants. Zn and Mn are imperative for the expression of MDS and their enhanced uptake in M plants could be responsible for the increased transcription of MDS. Furthermore, in the second stage of SGs biosynthesis pathway, mycorrhization enhanced the transcription of copalyl diphosphate synthase (CPPS) and kaurenoic acid hydroxylase (KAH). Their expression is decisive for SGs biosynthesis as CPPS regulates flow of metabolites towards synthesis of kaurenoid precursors and KAH directs these towards steviol synthesis instead of gibberellins. In the third stage glucosylation of steviol to reb-A by four specific uridine diphosphate (UDP)-dependent glycosyltransferases (UGTs) occurs. While higher transcription of all the three characterized UGTs in M plants explains augmented production of SGs; higher transcript levels of UGT76G1, specifically improved reb-A to stev ratio implying increased sweetness. The work signifies that AM symbiosis upregulates the transcription of all eleven SGs biosynthesis genes as a result of improved nutrition and enhanced sugar concentration due to increased photosynthesis in M plants.

  16. [Roles of reactive oxygen species in Streptomyces pactum Act12-induced tanshinone production in Salvia miltiorrhiza hairy roots].

    Science.gov (United States)

    Yan, Yan; Zhao, Xin; Zhang, Shun-Cang; Liu, Yan; Liang, Zong-Suo

    2014-06-01

    Our previous research indicated that the Streptomyces pactum Act12 (Act12) had a certain promotional effect on tanshinone accumulation and up-regulated the expression of genes 3-hydroxy-3-methyglutaryl-CoA reductase (HMGR) and 1-deoxy-d-xylulose-5-phosphate reductoisomerase (DXR) in Salvia miltiorrhiza hairy roots. This study focuses on the roles of reactive oxygen species in S. pactum Act12-induced tanshinone production in S. miltiorrhiza hairy roots. The 4% Act12, 4% Act12 + CAT and 4% Act12 + SOD were added to S. miltiorrhiza hairy root and subcultured for 21 days, the dry weight, contents of reactive oxygen species, contents of tanshinones and expression of HMGR and DXR were determined at different harvest-time. The generation of reactive oxygen species (ROS) in S. miltiorrhiza hairy roots was triggered by 4% Act12 treatment. The relative expressions of genes HMGR and DXR in 4% Act12 treatment were 32.4 and 4.8-fold higher than those in the control. And the total tanshinone in the hairy roots was 10.2 times higher than that of the control. The CAT and SOD could significantly inhibit the ROS accumulation and relative expressions of genes HMGR and DXR in 4% Act12 treatment, which induced the total tanshinone content was decreased by 74.6% comparing with the 4% Act12 treatment. ROS mediated Act12-induced tanshinone production. The Act12 may be via the ROS signal channel to activate the tanshinone biosynthesis pathways. Thereby the tanshinon content in hairy roots was increased.

  17. Enzymatic production and emission of floral scent volatiles in Jasminum sambac.

    Science.gov (United States)

    Bera, Paramita; Mukherjee, Chiranjit; Mitra, Adinpunya

    2017-03-01

    Floral scent composed of low molecular weight volatile organic compounds. The sweet fragrance of any evening blooming flower is dominated by benzenoid and terpenoid volatile compounds. Floral scent of Jasminum sambac (Oleaceae) includes three major benzenoid esters - benzylacetate, methylbenzoate, and methylsalicylate and three major terpene compounds viz. (E)-β-ocimene, linalool and α-farnesene. We analyzed concentrations and emission rates of benzenoids and terpenoids during the developmental stages of J. sambac flower. In addition to spatial emission from different floral parts, we studied the time-course mRNA accumulations of phenylalanine ammonia-lyase (PAL) and the two representative genes of terpenoid pathway, namely 1-deoxy-d-xylulose 5-phosphate reductoisomerase (DXR) and terpene synthase (TPS). Further, in vitro activities of several enzymes of phenylpropanoid/benzenoid pathway viz., PAL and acetyl-coenzyme A: benzylalcohol acetyltransferase (BEAT), S-adenosyl-l-methionine: benzoic acid carboxyl methyl transferase (BAMT) and S-adenosyl-l-methionine: salicylic acid carboxyl methyltransferase (SAMT) were studied. All the above enzyme activities along with the in vitro activities of DXR and TPS were found to follow a certain rhythm as observed in the emission of different benzenoid and terpenoid compounds. Linalool emission peaked after petal opening and coincided with maximal expression of JsTPS gene as evidenced from RT-PCR analyses (semi-quantitative). The maximum transcript accumulation of this gene was observed in flower petals, indicating that the petals of J. sambac flower play an important role as a major contributor of volatile precursors. The transcripts accumulation of JsDXR and JsTPS in different developmental stages and in different floral part showed that emissions of terpenoid volatiles in J. sambac flower are partially regulated at transcription levels. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  18. Relative expression of genes of terpene metabolism in different tissues of Artemisia annua L

    Directory of Open Access Journals (Sweden)

    Lundgren Anneli

    2011-03-01

    Full Text Available Abstract Background Recently, Artemisia annua L. (annual or sweet wormwood has received increasing attention due to the fact that the plant produces the sesquiterpenoid endoperoxide artemisinin, which today is widely used for treatment of malaria. The plant produces relatively small amounts of artemisinin and a worldwide shortage of the drug has led to intense research in order to increase the yield of artemisinin. In order to improve our understanding of terpene metabolism in the plant and to evaluate the competition for precursors, which may influence the yield of artemisinin, we have used qPCR to estimate the expression of 14 genes of terpene metabolism in different tissues. Results The four genes of the artemisinin biosynthetic pathway (amorpha-4,11-diene synthase, amorphadiene-12-hydroxylase, artemisinic aldehyde ∆11(13 reductase and aldehyde dehydrogenase 1 showed remarkably higher expression (between ~40- to ~500-fold in flower buds and young leaves compared to other tissues (old leaves, stems, roots, hairy root cultures. Further, dihydroartemisinic aldehyde reductase showed a very high expression only in hairy root cultures. Germacrene A and caryophyllene synthase were mostly expressed in young leaves and flower buds while epi-cedrol synthase was highly expressed in old leaves. 3-Hydroxy-3-methyl-glutaryl coenzyme A reductase exhibited lower expression in old leaves compared to other tissues. Farnesyldiphosphate synthase, squalene synthase, and 1-deoxy-D-xylulose-5-phosphate reductoisomerase showed only modest variation in expression in the different tissues, while expression of 1-deoxy-D-xylulose-5-phosphate synthase was 7-8-fold higher in flower buds and young leaves compared to old leaves. Conclusions Four genes of artemisinin biosynthesis were highly expressed in flower buds and young leaves (tissues showing a high density of glandular trichomes. The expression of dihydroartemisinic aldehyde reductase has been suggested to have a

  19. Effects of Gibberellic Acid on Primary Terpenoids and △9-Tetrahydrocannabinol in Cannabis sativa at Flowering Stage

    Institute of Scientific and Technical Information of China (English)

    Hakimeh Mansouri; Zahra Asrar; Mitra Mehrabani

    2009-01-01

    Plants synthesize an astonishing diversity of isoprenoids, some of which play essential roles in photosynthesis, respiration,and the regulation of growth and development. Two independent pathways for the biosynthesis of isoprenoid precursors coexist within the plant cell: the cytosolic mevalonic acid (MVA) pathway and the plastidial methylerythritol phosphate (MEP)pathway. However, little is known about the effects of plant hormones on the regulation of these pathways. In the present study we investigated the effect of gibberellic acid (GA3) on changes in the amounts of many produced terpenoids and the activity of the key enzymes, 1-deoxy-D-xylulose 5-phosphate synthase (DXS) and 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR), in these pathways. Our results showed GA3 caused a decrease in DXS activity in both sexes that it wasaccompanied by a decrease in chlorophylls, carotenoids and △9-tetrahydrocannabinol (THC) contents and an increase in α-tocopherol content. The treated plants with GA3 showed an increase in HMGR activity. This increase in HMGR activity was followed by accumulation of stigmasterol and β-sitosterol in male and female plants and campestrol in male plants.The pattern of the changes in the amounts of sterols was exactly similar to the changes in the HMGR activity. These data suggest that GA3 can probably influence the MEP and MVA pathways oppositely, with stimulatory and inhibitory effects on the produced primary terpenoids in MVA and DXS pathways, respectively.

  20. 75 FR 51449 - Notice of Proposed Information Collection Requests

    Science.gov (United States)

    2010-08-20

    ... Secondary Education Type of Review: Revision. Title: Migrant Education Program (MEP) Migrant Student... are collected and transferred between State migrant education programs (MEPs) as part of a larger mandated Migrant Student Information Exchange (MSIX). State educational agencies (SEAs) with MEPs...

  1. 75 FR 71675 - Notice of Submission for OMB Review

    Science.gov (United States)

    2010-11-24

    ... Review: Revision. Title of Collection: Migrant Education Program (MEP) Migrant Student Information... transferred between State migrant education programs (MEPs) as part of a larger mandated Migrant...

  2. Interaction between new synthesized derivative of (E,E)-azomethines and BN(6,6-7) nanotube for medical applications: Geometry optimization, molecular structure, spectroscopic (NMR, UV/Vis, excited state), FMO, MEP and HOMO-LUMO investigations

    Science.gov (United States)

    Sheikhi, Masoome; Shahab, Siyamak; Filippovich, Liudmila; Khaleghian, Mehrnoosh; Dikusar, Evgenij; Mashayekhi, Mahsa

    2017-10-01

    In this present work, first time interaction between new synthesized derivative of the 4-((E)-((4-((E)-phenyldiazenyl)phenyl)imino)methyl)benzoic acid (E-PABA) and the BN(6,6-7) Nanotube for medical applications were studied. The geometries of the compounds E-PABA, the BN(6,6-7) Nanotube and the Complex BN(6,6-7)/E-PABA were optimized by Density Functional Theory (DFT) in the gas phase. The adsorption effect of the compound E-PABA on the electronic properties, chemical shift tensors and natural charge of the BN(6,6-7) Nanotube was investigated and discussed. The electronic spectra of the E-PABA and the Complex BN(6,6-7)/E-PABA in the gas phase carried out by Time Dependent Density Functional Theory (TD-DFT) for the foundation adsorption effect on maximum wavelength of the E-PABA.

  3. Los textos literarios que asigna el MEP para el tercer ciclo de la educación general básica en Costa Rica: algunas reflexiones al respecto

    Directory of Open Access Journals (Sweden)

    Arias Orozco, Grettel

    2016-05-01

    Full Text Available En el presente artículo se detallan y analizan las principales modificaciones que presenta la lista de lecturas obligatorias propuesta en el año 2010 e implementada por el Ministerio de Educación Pública a partir del año 2011, en el Tercer Ciclo de la Educación General Básica costarricense. El estudio fue realizado a partir de la búsqueda bibliográfica de revistas especializadas, tesis de grado, libros, los Planes de Estudios de Español del 2005 y del año 2009, la lista de lecturas obligatorias implementada en el 2011, así como también gracias a entrevistas a especialistas en el área de la educación costarricense. Se concluye que las principales modificaciones responden a la dosificación, la categorización y la flexibilidad del listado de lecturas, pues la cantidad de textos y los géneros literarios que se estudian por nivel se modifican, así como también ahora se le brinda una gama de opciones al docente para que elija qué leer con su grupo estudiantil; no obstante, también se evidencia que ninguno de estos cambios ha sido debidamente fundamentado en la nueva propuesta. Finalmente, se destaca la incorporación de un corpus significativo de textos literarios que hacen referencia al personaje del presidente Juan Mora Porras, cuyo fin se vislumbra de carácter identitario e ideológico, pues su propósito es contrarrestar el desencanto político que ha aumentado en los últimos años e instaurarse como el nuevo referente del héroe nacional.

  4. Synthesis, growth, structural and HOMO and LUMO, MEP analysis of a new stilbazolium derivative crystal: A enhanced third-order NLO properties with a high laser-induced damage threshold for NLO applications

    Science.gov (United States)

    Senthil, K.; Kalainathan, S.; Hamada, F.; Yamada, M.; Aravindan, P. G.

    2015-08-01

    A new organic third-order nonlinear optical crystal from stilbazolium family 2-[2-(4-methoxy-phenyl) vinyl]-1-methyl-pyridinium tetrafluoroborate (4MSTB) has been synthesized and grown by slow evaporation method for the first time. The grown crystal structure was confirmed by single crystal X-ray diffraction analysis, and it is revealed that the grown crystal crystallized in a triclinic crystal system with centrosymmetric space group P 1 bar . The HOMO and LUMO energies were calculated for the grown crystal explains charge transfer takes place within the molecule and confirms the suitability of the title crystal for NLO applications. The presence of various vibration modes of expected functional groups was identified by FT-IR analysis. The transmittance ability of the grown crystal was also analyzed by using UV-Vis-NIR spectral studies and shows that the crystal has no absorption of light in the entire Vis-NIR region. The thermal stability of the title crystal has been investigated by TGA/DTA studies and revealed that the material was thermally stable up to the melting point, 193 °C. The hardness number, Meyer index, yield strength, and elastic stiffness constant has been estimated for the grown 4MSTB crystal using Vickers microhardness tester. Photoluminescence excitation studies showed green emission radiation occurred at 517 nm. The dielectric properties of the grown crystal have been analyzed as a function of temperature over a wide range of frequency (50 Hz-5 MHz) by using LCR meter. The result of ac electrical conductivity of 4MSTB was found to be 5.25 × 10-5 (Ω m)-1. The laser damage threshold (LDT) energy for the grown crystal has been measured by using a Q-switched Nd:YAG laser as a source in single-shot mode (1064 nm, 10 Hz, 420 mJ). The result of LDT indicates that grown title crystal has excellent resistance to laser radiation than those of known some inorganic NLO materials. The chemical etching studies were carried out to assess the perfection of the grown crystals. Its third-order nonlinear optical properties were investigated by Z-scan technique and proved that the 4MSTB crystal possesses two-photon absorptions (TPA) and the self-defocusing effect. The second-order molecular hyperpolarizability (γ) value at 632.8 nm is calculated to be 3.555 × 10-34 esu. The photoconductivity study of 4MSTB reveals that the negative photoconducting nature. The obtained all the results in the present work are making a 4MSTB promising candidate for the possible applications in optical switches, optical power limiter, and non-linear optical applications.

  5. FT-IR, NBO, HOMO-LUMO, MEP analysis and molecular docking study of Methyl N-({[2-(2-methoxyacetamido)-4-(phenylsulfanyl)phenyl]amino}[(methoxycarbonyl) imino]methyl)carbamate

    Science.gov (United States)

    Panicker, C. Yohannan; Varghese, Hema Tresa; Narayana, B.; Divya, K.; Sarojini, B. K.; War, Javeed Ahmad; Van Alsenoy, C.; Fun, H. K.

    2015-09-01

    The optimized molecular structure, vibrational frequencies, corresponding vibrational assignments of Methyl N-({[2-(2-methoxyacetamido)-4-(phenylsulfanyl) phenyl]amino} [(methoxycarbonyl)imino]methyl)carbamate have been investigated using HF and DFT levels of calculations. The geometrical parameters are in agreement with XRD data. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. The HOMO and LUMO analysis is used to determine the charge transfer within the molecule. Molecular electrostatic potential study was also performed. The first and second hyperpolarizability was calculated in order to find its role in nonlinear optics. Molecular docking studies are also reported. Prediction of Activity Spectra analysis of the title compound predicts anthelmintic and antiparasitic activity as the most probable activity with Pa (probability to be active) value of 0.808 and 0.797, respectively. Molecular docking studies show that both the phenyl groups and the carbonyl oxygens of the molecule are crucial for bonding and these results draw us to the conclusion that the compound might exhibit pteridine reductase inhibitory activity.

  6. Vibrational (FT-IR, FT-Raman) and UV-Visible spectroscopic studies, HOMO-LUMO, NBO, NLO and MEP analysis of Benzyl (imino (1H-pyrazol-1-yl) methyl) carbamate using DFT calculaions

    Science.gov (United States)

    Shankar Rao, Y. B.; Prasad, M. V. S.; Udaya Sri, N.; Veeraiah, V.

    2016-03-01

    This paper contains a combined experimental and theoretical study of vibrational and electronic properties of Benzyl(imino(1H-pyrazol-1-yl)methyl)carbamate (BPMC) molecule. The FT-IR and FT-Raman spectra of the title molecule in solid phase were recorded in the region 4000-400 cm-1 and 4000-50 cm-1, respectively. The UV absorption spectrum of the studied compound dissolved in ethanol was recorded in the range of 180-400 nm. The molecular geometries calculated using density functional theory (DFT) was compared with available experimental data. The vibrational spectra calculated at the B3LYP/6-31G(d,p) level were compared with the experimental spectra and assignment to each vibrational frequency was assigned on the basis of potential energy distribution (PED). The calculated electronic and nonlinear optical properties of the title molecule were reported. Furthermore, the thermodynamic properties of the molecule were discussed.

  7. Biosynthesis of sesquiterpenes in grape berry exocarp of Vitis vinifera L.: evidence for a transport of farnesyl diphosphate precursors from plastids to the cytosol.

    Science.gov (United States)

    May, Bianca; Lange, B Markus; Wüst, Matthias

    2013-11-01

    The participation of the mevalonic acid (MVA) and 1-deoxy-d-xylulose 5-phosphate/2-C-methyl-d-erythritol-4-phosphate (DOXP/MEP) pathways in sesquiterpene biosynthesis of grape berries was investigated. There is an increasing interest in this class of terpenoids, since the oxygenated sesquiterpene rotundone was identified as the peppery aroma impact compound in Australian Shiraz wines. To investigate precursor supply pathway utilization, in vivo feeding experiments were performed with the deuterium labeled, pathway specific, precursors [5,5-(2)H2]-1-deoxy-d-xylulose and [5,5-(2)H2]-mevalonic acid lactone. Head Space-Solid Phase Micro Extraction-Gas Chromatography-Mass Spectrometry (HS-SPME-GC-MS) analysis of the generated volatile metabolites demonstrated that de novo sesquiterpene biosynthesis is mainly located in the grape berry exocarp (skin), with no detectable activity in the mesocarp (flesh) of the Lemberger variety. Interestingly, precursors from both the (primarily) cytosolic MVA and plastidial DOXP/MEP pathways were incorporated into grape sesquiterpenes in the varieties Lemberger, Gewürztraminer and Syrah. Our labeling data provide evidence for a homogenous, cytosolic pool of precursors for sesquiterpene biosynthesis, indicating that a transport of precursors occurs mostly from plastids to the cytosol. The labeling patterns of the sesquiterpene germacrene D were in agreement with a cyclization mechanism analogous to that of a previously cloned enantioselective (R)-germacrene D synthase from Solidago canadensis. This observation was subsequently confirmed by enantioselective GC-MS analysis demonstrating the exclusive presence of (R)-germacrene D, and not the (S)-enantiomer, in grape berries.

  8. Changes in the transcriptional levels of pyridoxal kinase and pyridoxine-5'-phosphate oxidase post exogenous hormone treatment in the silkworm,Bombyx mori%外源激素处理后家蚕吡哆醛激酶和磷酸吡哆醇氧化酶转录水平的变化

    Institute of Scientific and Technical Information of China (English)

    杨欢欢; 姚丽丽; 张剑韵; 黄龙全

    2015-01-01

    [目的] 研究家蚕Bombyx mori经蜕皮激素(20-hydroxyecdysone,20-E)和保幼激素类似物(juvenile hormone analogue,JHA)处理后引起吡哆醛激酶(pyridoxal kinase,PLK)和磷酸吡哆醇氧化酶(pyridoxine-5'-phosphateoxidase,PNPO)的转录水平变化,为进一步研究激素对蚕体营养代谢等工作奠定基础.[方法]以20-E和JHA分别喂食不同发育时期(5龄第1,3和5天)的家蚕幼虫,以喂食蒸馏水的家蚕为对照,采用实时荧光定量PCR(real-time quantitative PCR)方法在处理后24和48 h对各组幼虫后部丝腺中PLP合成酶PLK和PNPO的转录水平进行分析.[结果]5龄第1天幼虫经20-E处理24和48 h后,PLK和PNPO的转录水平出现上调且与对照的差异达到极显著(P<0.01);5龄第3天幼虫经20-E处理,PLK的转录水平在48 h出现下调且与对照的差异达到显著(P<0.05),PNPO的转录水平在24和48 h均出现上调且与对照的差异达到极显著(P<0.01);5龄第5天幼虫经20-E处理后PLK和PNPO的转录水平无变化.5龄第1天幼虫经JHA处理后PLK和PNPO的转录水平未受到影响;5龄第3天幼虫经JHA处理后,PLK的转录水平在48 h出现显著下调且与对照的差异达到显著(P<0.05),PNPO的转录水平在24和48 h后均出现显著下调且与对照的差异达到极显著(P<0.05);5龄第5天幼虫经JHA处理24和48 h后,PLK和PNPO的转录水平出现下调且与对照的差异达到极显著(P<0.01).[结论]20-E和JHA显著影响家蚕5龄幼虫PLK和PNPO的转录水平,20-E提高5龄前期家蚕PLK和PNPO的转录水平,JHA降低5龄后期它们的转录水平,为深入研究激素对VB6的调控奠定基础.

  9. 家蚕酸吡哆醇氧化酶cDNA克隆、鉴定及基因结构分析%Cloning,Identification and Genomic Organization of the cDNA Encoding Pyridoxine 5'-phosphate Oxidase in Bombyx mori

    Institute of Scientific and Technical Information of China (English)

    张剑韵; 石瑞君; 黄硕豪; 黄龙全

    2008-01-01

    [目的]了解家蚕维生素B6关键代谢酶磷酸吡哆醇氧化酶(PNP0)的基因结构.[方法]利用生物信息学原理和PeR方法,克隆出编码家蚕(Bombyx mori)PNPO的cDNA(GenBank登录号:DQ452398);采用T7启动子/T7 RNA聚合酶原核表达系统对cDNA进行体外表达,并通过酶活检测进行表达产物的功能鉴定;依据家蚕基因组数据库信息和得到的cDNA,对家蚕PNPO基因结构进行分析.[结果]克隆到的cDNA含有771 bp的完整可读框,编码一条分子量为29.86 kD、含257个氨基酸残基的蛋白质.序列比对显示此蛋白质与人类PNPO具有51.44%的同源性,包含PNPO家族共有的保守序列,但在人和大肠杆菌PNPO中具有重要作用的几个氨基酸残基在此蛋白质中被替换.在以磷酸吡哆醇(PNP)为底物时,表达产物Pro-PNPO的酶活力约为17 nmol·min-1·mg-1.家蚕PNPO基因包含5个外显子和4个内含子,跨越3.5 kb DNA序列,所有外显子/内含子交接点都遵从gt/ag剪接规则,基因的5'端启动子调控区发现有TATA-box和CAAT-box保守基序.[结论]获得家蚕PNPO基因,可利用该基因在分子水平上研究家蚕的VB6代谢特征,弄清PNPO家族的特征及其在生物进化过程中的演变规律.

  10. Clinical characteristics and genetic analysis of 2 children with pyridox (am)ine-5'-phosphate oxidase deficiency%磷酸吡哆醇(胺)氧化酶缺乏症2例的临床特征及基因突变分析

    Institute of Scientific and Technical Information of China (English)

    薛姣; 杨志仙; 张月华; 姜玉武

    2016-01-01

    目的 分析2例磷酸吡哆醇(胺)氧化酶(PNPO)缺乏症患儿的临床特征及PNPO基因突变特征.方法 患儿为2016年2月于北京大学第一医院儿科确诊的同卵双生兄弟,对其临床表现、诊治过程、血液生化、代谢筛查、脑电图、头颅磁共振成像(MRI)、癫痫相关基因(包括PNPO基因)检测结果等进行分析.结果 2例患儿为35+5周早产,有出生窒息史.均于出生24h内出现癫痫发作,多种抗癫痫药效不佳.EEG显示不典型高度失律或多灶性癫痫样放电;MRI均显示非特异性异常.病程中曾应用维生素B6单药或添加多种抗癫痫药物治疗,维生素B6单药治疗过程中最长1个月未出现发作.5岁左右时,在发作仍持续存在过程中逐渐停用所有抗癫痫药物,近1年仅口服维生素B6治疗,至6岁4个月时仍均有发作.血代谢筛查示精氨酸、天门冬氨酸、蛋氨酸水平降低;尿代谢筛查示香草酸水平明显升高,2例分别为正常值的49.78倍、36.60倍.患儿基因分析证实均携带PNPO基因复合杂合变异:c.445_448del(p.P150RfsX27)和c.481C> T(p.R161C),均为国际上尚未报道的位点.确诊后,换用磷酸吡哆醛(PLP)治疗,短暂随访中,发作先略增多,后逐渐减少至完全控制.智力运动发育情况均为重度落后.结论 2例患儿均以新生儿期难治性癫痫起病,维生素B6对癫痫发作有一定疗效.血、尿代谢筛查提示了PNPO缺乏症的可能,最终经基因检测首次在国内确诊了此症,应用PLP单药治疗后发作控制.

  11. 77 FR 35399 - Proposed Collection; Comment Request

    Science.gov (United States)

    2012-06-13

    ... collection project: ``Medical Expenditure Panel Survey (MEPS) Household Component and the MEPS Medical... public to comment on this proposed information collection. DATES: Comments on this notice must be... Project Medical Expenditure Panel Survey (MEPS) Household Component and the MEPS Medical Provider...

  12. Enhanced Diterpene Tanshinone Accumulation and Bioactivity of Transgenic Salvia miltiorrhiza Hairy Roots by Pathway Engineering.

    Science.gov (United States)

    Shi, Min; Luo, Xiuqin; Ju, Guanhua; Li, Leilei; Huang, Shengxiong; Zhang, Tong; Wang, Huizhong; Kai, Guoyin

    2016-03-30

    Tanshinones are health-promoting diterpenoids found in Salvia miltiorrhiza and have wide applications. Here, SmGGPPS (geranylgeranyl diphosphate synthase) and SmDXSII (1-deoxy-D-xylulose-5-phosphate synthase) were introduced into hairy roots of S. miltiorrhiza. Overexpression of SmGGPPS and SmDXSII in hairy roots produces higher levels of tanshinone than control and single-gene transformed lines; tanshinone production in the double-gene transformed line GDII10 reached 12.93 mg/g dry weight, which is the highest tanshinone content that has been achieved through genetic engineering. Furthermore, transgenic hairy root lines showed higher antioxidant and antitumor activities than control lines. In addition, contents of chlorophylls, carotenoids, indoleacetic acid, and gibberellins were significantly elevated in transgenic Arabidopsis thaliana plants. These results demonstrate a promising method to improve the production of diterpenoids including tanshinone as well as other natural plastid-derived isoprenoids in plants by genetic manipulation of the 2-C-methyl-D-erythritol-4-phosphate (MEP) pathway.

  13. AcEST: DK948626 [AcEST

    Lifescience Database Archive (English)

    Full Text Available DTIQAD 129 >sp|Q72M00|ILVC_LEPIC Ketol-acid reductoisomerase OS=Leptospira interrogans serogroup Icterohaemorrhagiae serovar copenhag...eni GN=ilvC PE=3 SV=1 Length = 374 Score = 59.3 bits (14

  14. Host cells and methods for production of isobutanol

    Energy Technology Data Exchange (ETDEWEB)

    Anthony, Larry Cameron; He, Hongxian; Huang, Lixuan Lisa; Okeefe, Daniel P.; Kruckeberg, Arthur Leo; Li, Yougen; Maggio-Hall, Lori Ann; McElvain, Jessica; Nelson, Mark J.; Patnaik, Ranjan; Rothman, Steven Cary

    2016-08-23

    Provided herein are recombinant yeast host cells and methods for their use for production of isobutanol. Yeast host cells provided comprise an isobutanol biosynthetic pathway and at least one of reduced or eliminated aldehyde dehydrogenase activity, reduced or eliminated acetolactate reductase activity; or a heterologous polynucleotide encoding a polypeptide having ketol-acid reductoisomerase activity.

  15. Mars Technology Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA’s Mars Exploration Program (MEP) calls for a series of highly ambitious missions over the next decade and beyond. The overall goals of the MEP must be...

  16. Sequence Classification: 776671 [

    Lifescience Database Archive (English)

    Full Text Available ar zinc finger protein, Mog interacting, Ectopic P granules MEP-1, GEX (Gut on EXterior) Interacting protein GEI-2 (97.4 kD) (mep-1) || http://www.ncbi.nlm.nih.gov/protein/25152712 ...

  17. Navigated Transcranial Magnetic Stimulation: A Biologically Based Assay of Lower Extremity Impairment and Gait Velocity

    Science.gov (United States)

    Dunning, Kari; Ying, Jun; Laine, Jarmo; Page, Stephen J.

    2017-01-01

    Objectives. (a) To determine associations among motor evoked potential (MEP) amplitude, MEP latency, lower extremity (LE) impairment, and gait velocity and (b) determine the association between the presence of a detectable MEP signal with LE impairment and with gait velocity. Method. 35 subjects with chronic, stable LE hemiparesis were undergone TMS, the LE section of the Fugl-Meyer Impairment Scale (LE FM), and 10-meter walk test. We recorded presence, amplitude, and latency of MEPs in the affected tibialis anterior (TA) and soleus (SO). Results. MEP presence was associated with higher LEFM scores in both the TA and SO. MEP latency was larger in subjects with lower LEFM and difficulty walking. Conclusion. MEP latency appears to be an indicator of LE impairment and gait. Significance. Our results support the precept of using TMS, particularly MEP latency, as an adjunctive LE outcome measurement and prognostic technique. PMID:28243474

  18. 78 FR 9908 - Notice of Availability of the Draft Issuance of the Small Municipal Separate Storm Sewer System...

    Science.gov (United States)

    2013-02-12

    ... sewer systems in municipalities such as systems at military bases, large hospital or prison complexes... meet the MEP standard. The iterative process of MEP consists of a municipality developing a...

  19. 茶树挥发性萜类物质及其糖苷化合物生物合成的研究进展%Progress in the Research of Biosynthesis of Volatile Terpenoids and Their Glycosides in Tea Plant

    Institute of Scientific and Technical Information of China (English)

    贺志荣; 项威; 徐燕; 高丽萍; 夏涛; 魏书

    2012-01-01

    挥发性单萜(C10)与倍半萜(C15),常具有宜人的花果香气.茶鲜叶中此类物质的种类及其糖苷化合物的含量和水解对成品茶的香气香型有重要影响.就可能影响茶树挥发性萜类物质及其糖苷化合物合成途径中的限速反应和相关的酶进行综述,认为1-脱氧-D-木酮糖-5-磷酸还原异构酶(DXR)和羟甲基戊二酰辅酶A还原酶(HMGR)是影响萜类代谢前体异戊烯基焦磷酸(IPP)及二甲烯丙基焦磷酸(DMAPP)的限速酶.单萜和倍半萜合成酶是挥发性萜类化合物生物合成途径中的关键酶.此外,糖基转移酶可能与茶鲜叶中糖苷态萜类香气化合物的合成和积累有关.糖苷水解酶则催化茶鲜叶中糖苷态香气物质的水解,导致香气物质的释放.调节相关基因的表达,将有可能控制萜类代谢流向挥发性萜类合成分支.本文还讨论了影响茶叶香气品质的其他因素,如茶树品种、栽培环境,以及加工方法等.%Tea aromatic quality is largely dependent on the spectrum and abundance of volatile terpenoids and their glycosides produced and accumulated in tea leaves. Very often, the compounds of monoterpenes (C10) and sesquinterpene (C15) possess pleasant floral scent, contributing significantly to tea aromatic quality. However, studying on the biosynthesis pathway of these volatile terpenoids and their glycosides in tea plant is just at beginning. In this review, speed-limiting biosynthetic steps and related enzymes in plant volatile terpenoid biosynthesis pathways are summarized. The genes encoding 1-deoxy-D-xylulose-5 -phosphate reductoisomerase (DXR) and 3-hydroxyl-3-methylglutaryl-CoA reductase (HMGR) as well as terpenoid synthases are proposed as key enzymes for volatile terpenoid biosynthesis. Uridine diphosphate-glycosyltransferase may affect biosynthesis and accumulation of glycosides of volatile terpenoids in tea plant while glycosidase play a key role in the glycoside hydrolysis and release of

  20. Motor-evoked potential gain is a helpful test for the detection of corticospinal tract dysfunction in amyotrophic lateral sclerosis.

    Science.gov (United States)

    Duclos, Y; Grapperon, A M; Jouve, E; Truillet, R; Zemmour, C; Verschueren, A; Pouget, J; Attarian, S

    2017-02-01

    The detection of upper motor neuron (UMN) dysfunction is necessary for the diagnosis of amyotrophic lateral sclerosis (ALS). However, signs of UMN dysfunction may be difficult to establish. This study aimed to determine whether motor-evoked potential (MEP) gain (MEP area/background electromyographic activity) represents an efficient alternative to assess UMN dysfunction. MEP area, MEP/compound muscle action potential (CMAP) area ratio, and MEP gain were tested at different force levels in healthy control subjects and ALS patients. Receiver operating characteristic (ROC) curve analyses was used to determine the diagnostic utility of MEP gain and compare it to alternative techniques, namely, diffusion tensor imaging (DTI) and the triple stimulation technique (TST). MEP gain revealed a significant difference between the patients and healthy control subjects in contrast to MEP area and MEP/CMAP area ratio. The diagnostic utility of MEP gain was comparable with that of TST and superior to that of DTI. MEP gain can distinguish ALS patients from control subjects and may be helpful for the diagnosis of ALS. MEP gain appears to be a useful adjunct test and noninvasive method for the assessment of corticospinal dysfunction. Copyright © 2016 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

  1. The Carotenogenesis Pathway via the Isoprenoid-β-carotene Interference Approach in a New Strain of Dunaliella salina Isolated from Baja California Mexico

    Directory of Open Access Journals (Sweden)

    Luis Enrique Gutierrez-Millan

    2009-02-01

    Full Text Available D. salina is one of the recognized natural sources to produce β-carotene, and an useful model for studying the role of inhibitors and enhancers of carotenogenesis. However there is little information in D. salina regarding whether the isoprenoid substrate can be influenced by stress factors (carotenogenic or selective inhibitors which in turn may further contribute to elucidate the early steps of carotenogenesis and biosynthesis of β-carotene. In this study,Dunaliella salina (BC02 isolated from La Salina BC Mexico, was subjected to the method of isoprenoids-β-carotene interference in order to promote the interruption or accumulation of the programmed biosynthesis of carotenoids. When Carotenogenic and non-carotenogenic cells of D. salina BC02 were grown under photoautotrophicgrowth conditions in the presence of 200 µM fosmidomycin, carotenogenesis and the synthesis of β-carotene were interrupted after two days in cultured D. salina cells. This result is an indirect consequence of the inhibition of the synthesis of isoprenoids and activity of the recombinant DXR enzyme thereby preventing the conversionof 1-deoxy-D-xylulose 5-phosphate (DXP to 2-C-methyl-D-erythritol (MEP and consequently interrupts the early steps of carotenogenesis in D. salina. The effect at the level of proteins and RNA was not evident. Mevinolin treated D. salina cells exhibited carotenogenesis and β-carotene levels very similar to those of control cell cultures indicating that mevinolin not pursued any indirect action in the biosynthesis of isoprenoids and had no effect at the level of the HMG-CoA reductase, the key enzyme of the Ac/MVA pathway.

  2. Direct cortical stimulation but not transcranial electrical stimulation motor evoked potentials detect brain ischemia during brain tumor resection.

    Science.gov (United States)

    Li, Fenghua; Deshaies, Eric M; Allott, Geoffrey; Canute, Gregory; Gorji, Reza

    2011-09-01

    Motor evoked potentials (MEPs) elicited by both direct cortical stimulation (DCS) and transcranial electrical stimulation are used during brain tumor resection. Parallel use of direct cortical stimulation motor evoked potentials (DCS-MEPs) and transcranial electrical stimulation motor evoked potentials (TCeMEPs) has been practiced during brain tumor resection. We report that DCS-MEPs elicited by direct subdural grid stimulation, but not TCeMEPs, detected brain ischemia during brain tumor resection. Following resection of a brainstem high-grade glioma in a 21-year-old, the threshold of cortical motor-evoked-potentials (cMEPs) increased from 13 mA to 20 mA while amplitudes decreased. No changes were noted in transcranial motor evoked potentials (TCMEPs), somatosensory evoked potentials (SSEPs), auditory evoked potentials (AEPs), anesthetics, or hemodynamic parameters. Our case showed the loss of cMEPs and SSEPs, but not TCeMEPs. Permanent loss of DCS-MEPs and SSEPs was correlated with permanent left hemiplegia in our patient even when appropriate action was taken. Parallel use of DCS- and TCeMEPs with SSEPs improves sensitivity of intraoperative detection of motor impairment. DCS may be superior to TCeMEPs during brain tumor resection.

  3. Different Effects of Implicit and Explicit Motor Sequence Learning on Latency of Motor Evoked Potential Evoked by Transcranial Magnetic Stimulation on the Primary Motor Cortex

    Science.gov (United States)

    Hirano, Masato; Kubota, Shinji; Koizume, Yoshiki; Tanaka, Shinya; Funase, Kozo

    2017-01-01

    Motor training induces plastic changes in the primary motor cortex (M1). However, it is unclear whether and how the latency of motor-evoked potentials (MEP) and MEP amplitude are affected by implicit and/or explicit motor learning. Here, we investigated the changes in M1 excitability and MEP latency induced by implicit and explicit motor learning. The subjects performed a serial reaction time task (SRTT) with their five fingers. In this task, visual cues were lit up sequentially along with a predetermined order. Through training, the subjects learned the order of sequence implicitly and explicitly. Before and after the SRTT, we recorded MEP at 25 stimulation points around the hot spot for the flexor pollicis brevis (FPB) muscle. Although no changes in MEP amplitude were observed in either session, we found increases in MEP latency and changes in histogram of MEP latency after implicit learning. Our results suggest that reorganization across the motor cortices occurs during the acquisition of implicit knowledge. In contrast, acquisition of explicit knowledge does not appear to induce the reorganization based on the measures we recorded. The fact that the above mentioned increases in MEP latency occurred without any alterations in MEP amplitude suggests that learning has different effects on different physiological signals. In conclusion, our results propose that analyzing a combination of some indices of M1 excitability, such as MEP amplitude and MEP latency, is encouraged in order to understand plasticity across motor cortices. PMID:28101014

  4. NEW APPROACH FOR RELIABILITY-BASED DESIGN OPTIMIZATION: MINIMUM ERROR POINT

    Institute of Scientific and Technical Information of China (English)

    LIU Deshun; YUE Wenhui; ZHU Pingyu; DU Xiaoping

    2006-01-01

    Conventional reliability-based design optimization (RBDO) requires to use the most probable point (MPP) method for a probabilistic analysis of the reliability constraints. A new approach is presented, called as the minimum error point (MEP) method or the MEP based method,for reliability-based design optimization, whose idea is to minimize the error produced by approximating performance functions. The MEP based method uses the first order Taylor's expansion at MEP instead of MPP. Examples demonstrate that the MEP based design optimization can ensure product reliability at the required level, which is very imperative for many important engineering systems. The MEP based reliability design optimization method is feasible and is considered as an alternative for solving reliability design optimization problems. The MEP based method is more robust than the commonly used MPP based method for some irregular performance functions.

  5. Prospective Evaluation of the Energy and CO2 Emissions Impact of China’s 2010 – 2013 Efficiency Standards for Products

    Energy Technology Data Exchange (ETDEWEB)

    Khanna, Nina [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Technologies Area. China Energy Group; Zhou, Nan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Technologies Area. China Energy Group; Fridley, David [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Technologies Area. China Energy Group; McNeil, Michael [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). International Energy Studies Group

    2016-07-01

    Since China introduced its first mandatory minimum energy performance standards (MEPS) for eight major household products in 1989, its MEPS program has expanded significantly to cover nearly 60 residential, industrial and commercial products. In June of 2012, the pace of standards development for new and revised standards was further accelerated with the launch of the national “100 Energy Efficiency Standards.” Initiatives. An unprecedented 21 MEPS were adopted by China from 2012 to 2013, compared to only 7 MEPS adopted from 2010 to 2011. The Chinese MEPS program now covers 15 products in the residential sector, 15 types of commercial and office equipment, 14 types of industrial equipment and 13 lighting products, making it one of the most comprehensive MEPS program in the world. This study provides an updated prospective evaluation of the potential energy and CO2 impact of 23 of the 28 MEPS adopted by China from 2010 to 2013. This study updates a previous analysis (Zhou et al. 2011) by quantifying the additional potential energy and CO2 reductions from the newest standards that have been adopted since 2010. The most recent actual and projected sales, usage, and efficiency data were collected for 14 product categories covered under 23 MEPS adopted between 2010 and 2013. Three scenarios are then used to quantify the energy and CO2 reduction potential of the one-time implementation of these 23 MEPS, including a baseline counterfactual scenario, the actual MEPS scenario and a best available technologies efficiency scenario. The setting of the baseline efficiency is crucial to determining the savings potential of the new and revised MEPS and international best available technology efficiency levels, as it reflects the market average in the absence of MEPS. For this study, the average baseline is based on either the reported 2010 market-average efficiency if sales-weighted efficiency data is available for new product MEPS and

  6. The Maximum Entropy Production Principle: Its Theoretical Foundations and Applications to the Earth System

    OpenAIRE

    J. G. Dyke; Kleidon, A.

    2010-01-01

    The Maximum Entropy Production (MEP) principle has been remarkably successful in producing accurate predictions for non-equilibrium states. We argue that this is because the MEP principle is an effective inference procedure that produces the best predictions from the available information. Since all Earth system processes are subject to the conservation of energy, mass and momentum, we argue that in practical terms the MEP principle should be applied to Earth system processes in terms of the ...

  7. AcEST: DK954114 [AcEST

    Lifescience Database Archive (English)

    Full Text Available GN=Ncl PE=1 SV=3 35 0.36 sp|Q61SK8|MEP1_CAEBR MOG interacting and ectopic P-granules prot... 34 0.47 sp|Q9BY...>sp|Q61SK8|MEP1_CAEBR MOG interacting and ectopic P-granules protein 1 OS=Caenorhabditis briggsae GN=mep-1 P

  8. Characterization of dengue virus 2 growth in megakaryocyte–erythrocyte progenitor cells

    Energy Technology Data Exchange (ETDEWEB)

    Clark, Kristina B. [Division of Microbiology and Immunology, Yerkes National Primate Research Center, Emory University, Atlanta, GA (United States); Hsiao, Hui-Mien; Bassit, Leda [Center for AIDS Research, Department of Pediatrics, Emory University School of Medicine and Veterans Affairs Medical Center, Atlanta, GA (United States); Crowe, James E. [Departments of Pediatrics, Pathology, Microbiology, and Immunology, Vanderbilt University, Nashville, TN (United States); Schinazi, Raymond F. [Center for AIDS Research, Department of Pediatrics, Emory University School of Medicine and Veterans Affairs Medical Center, Atlanta, GA (United States); Perng, Guey Chuen [Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan (China); Villinger, Francois [Division of Microbiology and Immunology, Yerkes National Primate Research Center, Emory University, Atlanta, GA (United States); New Iberia Research Center, University of Louisiana at Lafayette, New Iberia, LA (United States)

    2016-06-15

    Megakaryocyte–erythrocyte progenitor (MEP) cells are potential in vivo targets of dengue virus (DENV); the virus has been found associated with megakaryocytes ex vivo and platelets during DENV-induced thrombocytopenia. We report here that DENV serotype 2 (DENV2) propagates well in human nondifferentiated MEP cell lines (Meg01 and K562). In comparison to virus propagated in Vero cells, viruses from MEP cell lines had similar structure and buoyant density. However, differences in MEP-DENV2 stability and composition were suggested by distinct protein patterns in western blot analysis. Also, antibody neutralization of envelope domain I/II on MEP-DENV2 was reduced relative to that on Vero-DENV2. Infectious DENV2 was produced at comparable kinetics and magnitude in MEP and Vero cells. However, fewer virion structures appeared in electron micrographs of MEP cells. We propose that DENV2 infects and produces virus efficiently in megakaryocytes and that megakaryocyte impairment might contribute to dengue disease pathogenesis. - Highlights: • DenV replicates efficiently in undifferentiated megakaryocyte–erythrocyte progenitors. • MEP produced DenV differs in protein content from Vero produced DenV. • MEP produced DenV may be more difficult to neutralize relative to Vero DenV.

  9. The European Parliament's Rejection of the Take-over Directive Proposal

    DEFF Research Database (Denmark)

    Steen Knudsen, Jette

    2003-01-01

    This article examines why Members of the European Parliament (MEPs) in 2001 turneddown a proposal for an EU take-over directive? The first explanation focuses on partyideology. However, MEPs overwhelmingly voted according to national rather than partylines. Two additional explanations emphasise...... national characteristics: labour marketlegislation (national schemes to protect employees against dismissals) and corporategovernance issues. Labour market legislation can explain the UK and German MEP votesbut not the Swedish and French MEPs votes. These votes can be explained byemphasising measures...... against take-overs such as a high level of market capitalisation andunequal voting rights....

  10. Screening and determination of drugs in human saliva utilizing microextraction by packed sorbent and liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Abdel-Rehim, Abbi; Abdel-Rehim, Mohamed

    2013-09-01

    This study presents a new method for collecting and handling saliva samples using an automated analytical microsyringe and microextraction by packed syringe (MEPS). The screening and determination of lidocaine in human saliva samples utilizing MEPS and liquid chromatography-tandem mass spectrometry (LC-MS/MS) were carried out. An exact volume of saliva could be collected. The MEPS C8 -cartridge could be used for 50 extractions before it was discarded. The extraction recovery was about 60%. The pharmacokinetic curve of lidocaine in saliva using MEPS-LC-MS/MS is reported.

  11. Multiplication of an ancestral gene encoding secreted fungalysin preceded species differentiation in the dermatophytes Trichophyton and Microsporum.

    Science.gov (United States)

    Jousson, Olivier; Léchenne, Barbara; Bontems, Olympia; Capoccia, Sabrina; Mignon, Bernard; Barblan, Jachen; Quadroni, Manfredo; Monod, Michel

    2004-02-01

    Dermatophytes are human and animal pathogenic fungi which cause cutaneous infections and grow exclusively in the stratum corneum, nails and hair. In a culture medium containing soy proteins as sole nitrogen source a substantial proteolytic activity was secreted by Trichophyton rubrum, Trichophyton mentagrophytes and Microsporum canis. This proteolytic activity was 55-75 % inhibited by o-phenanthroline, attesting that metalloproteases were secreted by all three species. Using a consensus probe constructed on previously characterized genes encoding metalloproteases (MEP) of the M36 fungalysin family in Aspergillus fumigatus, Aspergillus oryzae and M. canis, a five-member MEP family was isolated from genomic libraries of T. rubrum, T. mentagrophytes and M. canis. A phylogenetic analysis of genomic and protein sequences revealed a robust tree consisting of five main clades, each of them including a MEP sequence type from each dermatophyte species. Each MEP type was remarkably conserved across species (72-97 % amino acid sequence identity). The tree topology clearly indicated that the multiplication of MEP genes in dermatophytes occurred prior to species divergence. In culture medium containing soy proteins as a sole nitrogen source secreted Meps accounted for 19-36 % of total secreted protein extracts; characterization of protein bands by proteolysis and mass spectrometry revealed that the three dermatophyte species secreted two Meps (Mep3 and Mep4) encoded by orthologous genes.

  12. Antigenotoxic potencies of a lichen species, Evernia prunastri.

    Science.gov (United States)

    Alpsoy, Lokman; Orhan, Furkan; Nardemir, Gokce; Agar, Guleray; Gulluce, Medine; Aslan, Ali

    2015-02-01

    In this article, the genotoxic and antigenotoxic effects of methanol extract of Evernia prunastri (Huds.) Willd. (MEP) were studied using WP2, Ames (TA1535 and TA1537) and sister chromatid exchange (SCE) test systems. The results obtained from bacterial test systems demonstrated that MEP has strong antimutagenic potencies on TA1537 and WP2 strains. The highest inhibition rates for MEP on TA1537 and WP2 strains were 37.70% and 69.70%, respectively. According to the SCE test system, MEP reduced the genotoxic effects of aflatoxin. In order to clarify the mechanism underlying the antigenotoxic effects of MEP, the antioxidants were determined. Cotreatments of 5, 10 and 20 µg/mL concentrations of MEP with aflatoxin B1 decreased the frequencies of SCE and the malondialdehyde level and increased amount of superoxide dismutase, glutathione and glutathione peroxidase which were decreased by aflatoxin. The data obtained from this work have clearly shown that MEP has significant antigenotoxic effects which are thought to be partly due to the antioxidant activities and antioxidant inducing capability of MEP. This is the first report indicating the antigenotoxic activities of MEP against several mutagen agents such as N-methyl-N'-nitro-N-nitrosoguanidine, acridin and aflatoxin. © The Author(s) 2012.

  13. Evaluating the Association between Acute and Chronic Pain after Surgery

    DEFF Research Database (Denmark)

    Gilron, Ian; Vandenkerkhof, Elizabeth; Katz, Joel

    2017-01-01

    /7 reported an association for PAR only and 1/7 reported an association for MEP only. Six of another 7 studies reporting only the association for MEP found a significant relationship. Three of the 5 studies that did not specify whether acute pain outcomes were PAR or MEP reported a significant relationship....... Another 3 studies reporting a relationship with CPSP did not specify whether this was for PAR, MEP or both. All investigations incorporating severity of CPSP in their analyses (n=7) demonstrated a significant relationship, whereas only 10 of the 15 studies that dichotomized CPSP outcome as "no pain...

  14. 78 FR 41185 - Denial of Exemption Applications; Epilepsy and Seizure Disorders

    Science.gov (United States)

    2013-07-09

    ... epilepsy or any other condition which is likely to cause a loss of consciousness or any loss of ability to... or any other condition which is likely to cause the loss of consciousness or any loss of ability to... notice. MEP Criteria for Evaluation On October 15, 2007, the MEP issued the following...

  15. Stimulus-response characteristics of motor evoked potentials and silent periods in proximal and distal upper-extremity muscles.

    NARCIS (Netherlands)

    Kuijk, A.A. van; Anker, L.C.; Pasman, J.W.; Hendriks, J.C.M.; Elswijk, G.A.F. van; Geurts, A.C.H.

    2009-01-01

    OBJECTIVE: To compare stimulus-response characteristics of both motor evoked potentials (MEP) and silent periods (SP) induced by transcranial magnetic stimulation (TMS) in proximal and distal upper-extremity muscles. METHODS: Stimulus-response curves of MEPs and SPs were obtained from the biceps bra

  16. 78 FR 79613 - Final Requirement-Migrant Education Program Consortium Incentive Grant Program

    Science.gov (United States)

    2013-12-31

    ... Education Program (MEP) Consortium Incentive Grant (CIG) Program. This final requirement changes the maximum project period of grants awarded to State educational agencies (SEAs) under the MEP CIG program from two... established in their approved CIG program application. DATES: Effective Date: This requirement is effective...

  17. Microelectronics in Education--A Changing Future.

    Science.gov (United States)

    Humphries, Chris

    1985-01-01

    Describes major program activities of Microelectronics Education Programme (MEP) for England, Wales, and Northern Ireland, which is designed to help schools prepare children for society with microelectronics. The core elements and potential consequences of the Microelectronics Support Unit, a follow-up to MEP which will conclude activities in…

  18. Psychometric properties of the Mayo Elbow Performance Score.

    Science.gov (United States)

    Celik, Derya

    2015-06-01

    To translate and culturally adapt the Mayo Elbow Performance Score (MEPS), a widely used instrument for evaluating disability associated with elbow injuries, into Turkish (MEPS-T) and to determine psychometric properties of the translated version. The MEPS was translated into Turkish using published methodological guidelines. The measurement properties of the MEPS-T (construct validity and floor and ceiling effects) were tested in 91 patients with elbow pathology. The reproducibility of the MEPS-T was tested in 59 patients over 7-14 days. The responsiveness of the MEPS-T was tested in a subgroup of 46 patients diagnosed with lateral epicondylitis and who received conservative treatment for 6 weeks. The interclass correlation coefficient (ICC) was used to estimate the test-retest reliability. The construct validity was analyzed with the disabilities of the arm, shoulder and hand (DASH), Visual Analog Scale (VAS) and the Short Form 36 (SF-36). Effect size (ES) was used to assess the responsiveness. The distribution of floor and ceiling effects was determined. The MEPS-T showed very good test-retest reliability (ICC 0.89). The correlation coefficients between the MEPS-T and DASH and VAS were -0.61 and -0.53, respectively (p elbow disease.

  19. Wideband energy reflectance measurements: effects of negative middle ear pressure and application of a pressure compensation procedure.

    Science.gov (United States)

    Shaver, Mark D; Sun, Xiao-Ming

    2013-07-01

    The wideband energy reflectance (ER) technique has become popular as a tool for evaluating middle ear function. Negative middle ear pressure (MEP) is a prevalent form of middle ear dysfunction, which may impact application of ER measurements in differential diagnosis. A negative MEP may be countervailed by application of an equivalent negative ear canal pressure. The present study examined ER in the same ears under normal and experimentally induced negative MEP conditions. Thirty-five subjects produced at least one negative MEP each (-40 to -225 daPa). Negative MEP significantly altered ER in a frequency-specific manner that varied with MEP magnitude. ER increased for low- to mid-frequencies with the largest change (~0.20 to 0.40) occurring between 1 and 1.5 kHz. ER decreased for frequencies above 3 kHz with the largest change (~-0.10 to -0.25) observed between 4.5 and 5.5 kHz. Magnitude of changes increased as MEP became more negative, as did the frequencies at which maximum changes occurred, and the frequency at which enhancement transitioned to reduction. Ear canal pressure compensation restored ER to near baseline values. This suggests that the compensation procedure adequately mitigates the effects of negative MEP on ER. Theoretical issues and clinical implications are discussed.

  20. 27 May 2010 - Members of the Scientific and Technological Options Assessment Panel (STOA), European Parliament, visiting the LHC superconducting magnet test hall (SM18) with Technology Deputy Department Head L. Rossi and accompanied by CERN Head of the EU Project Office S. Stavrev and CERN EU Projects for Accelerator Technology and Coordinator of FP7 EuCRAD J.-P. Koutchouk.

    CERN Multimedia

    Jean-Claude Gadmer

    2010-01-01

    CERN-HI-1005086 tirage 16: The delegation was led by STOA Vice Chairman and Member of IMCO Committee A. F. Correia de Campos MEP and STOA Vice Chairman and IMCO Committee Chairman M. Harbour MEP (2nd and 3rd on this photograph).

  1. Recovery time of motor evoked potentials following lengthening and shortening muscle action in the tibialis anterior

    NARCIS (Netherlands)

    Tallent, J.; Goodall, S.; Hortobagyi, T.; Gibson, A. St Clair; French, D. N.; Howatson, G.

    2012-01-01

    Motor evoked potentials (MEP) at rest remain facilitated following an isometric muscle contraction. Because the pre-synaptic and post-synaptic control of shortening (SHO) and lengthening (LEN) contractions differs, the possibility exists that the recovery of the MEP is also task specific. The time c

  2. Prevalence and Costs of Five Chronic Conditions in Children

    Science.gov (United States)

    Miller, Gabrielle F.; Coffield, Edward; Leroy, Zanie; Wallin, Robin

    2016-01-01

    The objective is to examine the prevalence and health-care costs associated with asthma, epilepsy, hypertension, food allergies, and diabetes in children aged 0-18 years. Prevalence was calculated using 2005-2012 Medical Expenditure Panel Survey (MEPS) data, a population-based, nationally representative sample. Using MEPS, two-part models…

  3. Simplifying Contracts for Commercial Systems. A Case Study of DoD acquisition of Commercial Systems and Components. Volume 1

    Science.gov (United States)

    1980-01-01

    80 User Needs ...................................... .......... . 80 Market Research and Analysis .............................. 81...a strong consideration. Market Research and Analysis To conduct service testing of MEP generators other than the standard family of generators...MEP generators were bailed from each of the two manufacturers of the commercial generators. Service testing, as a part of t:,e market research and analysis to

  4. Stimulus-response characteristics of motor evoked potentials and silent periods in proximal and distal upper-extremity muscles.

    NARCIS (Netherlands)

    Kuijk, A.A. van; Anker, L.C.; Pasman, J.W.; Hendriks, J.C.M.; Elswijk, G.A.F. van; Geurts, A.C.H.

    2009-01-01

    OBJECTIVE: To compare stimulus-response characteristics of both motor evoked potentials (MEP) and silent periods (SP) induced by transcranial magnetic stimulation (TMS) in proximal and distal upper-extremity muscles. METHODS: Stimulus-response curves of MEPs and SPs were obtained from the biceps bra

  5. Sensory evoked potentials to predict short-term progression of disability in multiple sclerosis.

    Science.gov (United States)

    Margaritella, N; Mendozzi, L; Garegnani, M; Colicino, E; Gilardi, E; Deleonardis, L; Tronci, F; Pugnetti, L

    2012-08-01

    To devise a multivariate parametric model for short-term prediction of disability using the Expanded Disability Status Scale (EDSS) and multimodal sensory EP (mEP). A total of 221 multiple sclerosis (MS) patients who underwent repeated mEP and EDSS assessments at variable time intervals over a 20-year period were retrospectively analyzed. Published criteria were used to compute a cumulative score (mEPS) of abnormalities for each of 908 individual tests. Data of a statistically balanced sample of 58 patients were fed to a parametrical regression analysis using time-lagged EDSS and mEPS along with other clinical variables to estimate future EDSS scores at 1 year. Whole sample cross-sectional mEPS were moderately correlated with EDSS, whereas longitudinal mEPS were not. Using the regression model, lagged mEPS and lagged EDSS along with clinical variables provided better future EDSS estimates. The R (2) measure of fit was significant and 72% of EDSS estimates showed an error value of ±0.5. A parametrical regression model combining EDSS and mEPS accurately predicts short-term disability in MS patients and could be used to optimize decisions concerning treatment.

  6. AcEST: BP916380 [AcEST

    Lifescience Database Archive (English)

    Full Text Available 8|MEP1_CAEBR MOG interacting and ectopic P-granules prot... 31 2.9 sp|P15539|C11B2_MOUSE Cytochrome P450 11B...bjct: 117 QALIPQGADILPNPTGTAPGIIWEPRPDMTIFTFPGVPSE-MHRM 160 >sp|Q61SK8|MEP1_CAEBR MOG interacting and ectopic

  7. Botulinum Toxin Type A Injections in the Psoas Muscle of Children with Cerebral Palsy: Muscle Atrophy after Motor End Plate-Targeted Injections

    Science.gov (United States)

    Van Campenhout, Anja; Verhaegen, Ann; Pans, Steven; Molenaers, Guy

    2013-01-01

    MEP targeting during BoNT-A injections has been demonstrated to improve outcome. Two injection techniques of the psoas muscle--proximal MEP targeting versus a widely used more distal injection technique--are compared using muscle volume assessment by digital MRI segmentation as outcome measure. Method: 7 spastic diplegic children received…

  8. Botulinum Toxin Type A Injections in the Psoas Muscle of Children with Cerebral Palsy: Muscle Atrophy after Motor End Plate-Targeted Injections

    Science.gov (United States)

    Van Campenhout, Anja; Verhaegen, Ann; Pans, Steven; Molenaers, Guy

    2013-01-01

    MEP targeting during BoNT-A injections has been demonstrated to improve outcome. Two injection techniques of the psoas muscle--proximal MEP targeting versus a widely used more distal injection technique--are compared using muscle volume assessment by digital MRI segmentation as outcome measure. Method: 7 spastic diplegic children received…

  9. Heterologous expression and characterization of bacterial 2-C-methyl-d-erythritol-4-phosphate pathway in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Carlsen, Simon; Ajikumar, Parayil Kumaran; Formenti, Luca Riccardo;

    2013-01-01

    the engineering of Escherichia coli genes encoding the 2-C-methyl-d-erythritol-4-phosphate (MEP) pathway into the genome of Saccharomyces cerevisiae and the characterization of intermediate metabolites synthesized by the MEP pathway in yeast. Our UPLC-MS analysis of the MEP pathway metabolites from engineered...... yeast showed that the pathway is active until the synthesis of 2-C-methyl-d-erythritol-2,4-cyclodiphosphate, but appears to lack functionality of the last two steps of the MEP pathway, catalyzed by the [4Fe–4S] iron sulfur cluster proteins encoded by ispG and ispH. In order to functionalize the last two...... steps of the MEP pathway, we co-expressed the genes for the E. coli iron sulfur cluster (ISC) assembly machinery. By deleting ERG13, thereby incapacitating the mevalonate pathway, in conjunction with labeling experiments with U–13C6 glucose and growth experiments, we found that the ISC assembly...

  10. Using Transcranial Magnetic Stimulation to Evaluate the Motor Pathways After an Intraoperative Spinal Cord Injury and to Predict the Recovery of Intraoperative Transcranial Electrical Motor Evoked Potentials: A Case Report.

    Science.gov (United States)

    Grover, Helen J; Thornton, Rachel; Lutchman, Lennel N; Blake, Julian C

    2016-06-01

    The authors report a case of unilateral loss of intraoperative transcranial electrical motor evoked potentials (TES MEP) associated with a spinal cord injury during scoliosis correction and the subsequent use of extraoperative transcranial magnetic stimulation to monitor the recovery of spinal cord function. The authors demonstrate the absence of TES MEPs and absent transcranial magnetic stimulation responses in the immediate postoperative period, and document the partial recovery of transcranial magnetic stimulation responses, which corresponded to partial recovery of TES MEPs. Intraoperative TES MEPs were enhanced using spatial facilitation technique, which enabled the patient to undergo further surgery to stabilize the spine and correct her scoliosis. This case report supports evidence of the use of extraoperative transcranial magnetic stimulation to predict the presence of intraoperative TES responses and demonstrates the usefulness of spatial facilitation to monitor TES MEPs in a patient with a preexisting spinal cord injury.

  11. Francisella tularensis 2-C-methyl-D-erythritol 4-phosphate cytidylyltransferase: kinetic characterization and phosphoregulation.

    Directory of Open Access Journals (Sweden)

    Arthur Tsang

    Full Text Available Deliberate and natural outbreaks of infectious disease, the prevalence of antibiotic resistant strains, and the ease by which antibiotic resistant bacteria can be intentionally engineered all underscore the necessity of effective vaccines and continued development of novel antimicrobial/antiviral therapeutics. Isoprenes, a group of molecules fundamentally involved in a variety of crucial biological functions, are derived from either the mevalonic acid (MVA or methylerythritol phosphate (MEP pathway. While mammals utilize the MVA pathway, many bacteria utilize the MEP pathway, highlighting the latter as an attractive target for antibiotic development. In this report we describe the cloning and characterization of Francisella tularensis MEP cytidylyltransferase, a MEP pathway enzyme and potential target for antibiotic development. Size exclusion chromatography indicates the protein exists as a dimer in solution. Enzyme assays produced an apparentK(MEP(M = 178 μM, K(CTP(M = 73 μM , k(MEP(cat = 1(s-1, k(CTP(cat = 0.8( s-1, and a k(MEP(cat/ K(MEP(M = 3.4 x 10(5 M(-1 min(-1. The enzyme exhibits a strict preference for Mg(+2 as a divalent cation and CTP as the nucleotide. Titanium dioxide chromatography-tandem mass spectrometry identified Thr141 as a site of phosphorylation. T141D and T141E site-directed mutants are catalytically inactive, suggesting a mechanism for post-translational control of metabolic flux through the F. tularensis MEP pathway. Overall, our study suggests that MEP cytidylyltransferase is an excellent target for the development of novel antibiotics against F. tularensis.

  12. Dissociation of the pathways mediating ipsilateral and contralateral motor-evoked potentials in human hand and arm muscles

    Science.gov (United States)

    Ziemann, Ulf; Ishii, Kenji; Borgheresi, Alessandra; Yaseen, Zaneb; Battaglia, Fortunato; Hallett, Mark; Cincotta, Massimo; Wassermann, Eric M

    1999-01-01

    Growing evidence points toward involvement of the human motor cortex in the control of the ipsilateral hand. We used focal transcranial magnetic stimulation (TMS) to examine the pathways of these ipsilateral motor effects.Ipsilateral motor-evoked potentials (MEPs) were obtained in hand and arm muscles of all 10 healthy adult subjects tested. They occurred in the finger and wrist extensors and the biceps, but no response or inhibitory responses were observed in the opponens pollicis, finger and wrist flexors and the triceps.The production of ipsilateral MEPs required contraction of the target muscle. The threshold TMS intensity for ipsilateral MEPs was on average 1.8 times higher, and the onset was 5.7 ms later (in the wrist extensor muscles) compared with size-matched contralateral MEPs.The corticofugal pathways of ipsilateral and contralateral MEPs could be dissociated through differences in cortical map location and preferred stimulating current direction.Both ipsi- and contralateral MEPs in the wrist extensors increased with lateral head rotation toward, and decreased with head rotation away from, the side of the TMS, suggesting a privileged input of the asymmetrical tonic neck reflex to the pathway of the ipsilateral MEP.Large ipsilateral MEPs were obtained in a patient with complete agenesis of the corpus callosum.The dissociation of the pathways for ipsilateral and contralateral MEPs indicates that corticofugal motor fibres other than the fast-conducting crossed corticomotoneuronal system can be activated by TMS. Our data suggest an ipsilateral oligosynaptic pathway, such as a corticoreticulospinal or a corticopropriospinal projection as the route for the ipsilateral MEP. Other pathways, such as branching of corticomotoneuronal axons, a transcallosal projection or a slow-conducting monosynaptic ipsilateral pathway are very unlikely or can be excluded. PMID:10420023

  13. NCBI nr-aa BLAST: CBRC-LAFR-01-1256 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-LAFR-01-1256 ref|ZP_01754413.1| cobalamin 5'-phosphate synthase [Roseobacter s...p. SK209-2-6] gb|EBA16605.1| cobalamin 5'-phosphate synthase [Roseobacter sp. SK209-2-6] ZP_01754413.1 2.2 36% ...

  14. NCBI nr-aa BLAST: CBRC-LAFR-01-1256 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-LAFR-01-1256 ref|ZP_01056432.1| cobalamin 5'-phosphate synthase [Roseobacter s...p. MED193] gb|EAQ45647.1| cobalamin 5'-phosphate synthase [Roseobacter sp. MED193] ZP_01056432.1 1.00 32% ...

  15. Binding of divalent magnesium by Escherichia coli phosphoribosyl diphosphate synthetase

    DEFF Research Database (Denmark)

    Willemoës, Martin; Hove-Jensen, Bjarne

    1997-01-01

    The mechanism of binding of the substrates Mg x ATP and ribose 5-phosphate as well as Mg2+ to the enzyme 5-phospho-D-ribosyl (alpha-1-diphosphate synthetase from Escherichia coli has been analyzed. By use of the competive inhibitors of ATP and ribose 5-phosphate binding, alpha,beta-methylene ATP ...

  16. NCBI nr-aa BLAST: CBRC-RMAC-09-0015 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-RMAC-09-0015 ref|ZP_01522583.1| cobalamin-5-phosphate synthase CobS [Comamonas... testosteroni KF-1] gb|EAV12997.1| cobalamin-5-phosphate synthase CobS [Comamonas testosteroni KF-1] ZP_01522583.1 0.46 40% ...

  17. Synthesis, Structure and Biological Activities of Some Novel N-(4,6-Disubstituted-pyrimidin-2-yl)-N'-(trifluoromethylphenyl)-guanidine Derivatives

    Institute of Scientific and Technical Information of China (English)

    HE Feng-Qi; LIU Xing-Hai; WANG Bao-Lei; LI Yong-Hong; LI Zheng-Ming

    2008-01-01

    A novel series of guanidine derivatives were designed, synthesized and confirmed by FTIR, MS, 1H NMR and elemental analysis. The single crystal structure of 11b was determined by X-ray diffraction. Herbicidal activities of these guanidine derivatives were evaluated through barnyardgrass and rape cup tests, among which compounds lla, lib, and lie against Brassica campestris reached 71.2%, 86.7%, and 86.9% at 100 μg·mL-1 respectively. The preliminary ketol-acid reductoisomerase test showed that the synthesized compounds had weak activities.

  18. Methods for library-scale computational protein design.

    Science.gov (United States)

    Johnson, Lucas B; Huber, Thaddaus R; Snow, Christopher D

    2014-01-01

    Faced with a protein engineering challenge, a contemporary researcher can choose from myriad design strategies. Library-scale computational protein design (LCPD) is a hybrid method suitable for the engineering of improved protein variants with diverse sequences. This chapter discusses the background and merits of several practical LCPD techniques. First, LCPD methods suitable for delocalized protein design are presented in the context of example design calculations for cellobiohydrolase II. Second, localized design methods are discussed in the context of an example design calculation intended to shift the substrate specificity of a ketol-acid reductoisomerase Rossmann domain from NADPH to NADH.

  19. Nucleic and amino acid sequences relating to a novel transketolase, and methods for the expression thereof

    Energy Technology Data Exchange (ETDEWEB)

    Croteau, Rodney Bruce (Pullman, WA); Wildung, Mark Raymond (Colfax, WA); Lange, Bernd Markus (Pullman, WA); McCaskill, David G. (Pullman, WA)

    2001-01-01

    cDNAs encoding 1-deoxyxylulose-5-phosphate synthase from peppermint (Mentha piperita) have been isolated and sequenced, and the corresponding amino acid sequences have been determined. Accordingly, isolated DNA sequences (SEQ ID NO:3, SEQ ID NO:5, SEQ ID NO:7) are provided which code for the expression of 1-deoxyxylulose-5-phosphate synthase from plants. In another aspect the present invention provides for isolated, recombinant DXPS proteins, such as the proteins having the sequences set forth in SEQ ID NO:4, SEQ ID NO:6 and SEQ ID NO:8. In other aspects, replicable recombinant cloning vehicles are provided which code for plant 1-deoxyxylulose-5-phosphate synthases, or for a base sequence sufficiently complementary to at least a portion of 1-deoxyxylulose-5-phosphate synthase DNA or RNA to enable hybridization therewith. In yet other aspects, modified host cells are provided that have been transformed, transfected, infected and/or injected with a recombinant cloning vehicle and/or DNA sequence encoding a plant 1-deoxyxylulose-5-phosphate synthase. Thus, systems and methods are provided for the recombinant expression of the aforementioned recombinant 1-deoxyxylulose-5-phosphate synthase that may be used to facilitate its production, isolation and purification in significant amounts. Recombinant 1-deoxyxylulose-5-phosphate synthase may be used to obtain expression or enhanced expression of 1-deoxyxylulose-5-phosphate synthase in plants in order to enhance the production of 1-deoxyxylulose-5-phosphate, or its derivatives such as isopentenyl diphosphate (BP), or may be otherwise employed for the regulation or expression of 1-deoxyxylulose-5-phosphate synthase, or the production of its products.

  20. TMS-induced motor evoked potentials in Wilson's disease: a systematic literature review.

    Science.gov (United States)

    Bembenek, Jan P; Kurczych, Katarzyna; Członkowska, Anna

    2015-04-01

    Wilson's disease (WD) is a metabolic brain disease resulting from improper copper metabolism. Although pyramidal symptoms are rarely observed, subclinical injury is highly possible as copper accumulates in all brain structures. The usefulness of motor evoked potentials (MEPs) in pyramidal tracts damage evaluation still appears to be somehow equivocal. We searched for original papers assessing the value of transcranial magnetic stimulation elicited MEPs with respect to motor function of upper and lower extremity in WD. We searched PubMed for original papers evaluating use of MEPs in WD using key words: "motor evoked potentials Wilson's disease" and "transcranial magnetic stimulation Wilson's disease." We found six articles using the above key words. One additional article and one case report were found while viewing the references lists. Therefore, we included eight studies. Number of patients in studies was low and their clinical characteristic was variable. There were also differences in methodology. Abnormal MEPs were confirmed in 20-70% of study participants. MEPs were not recorded in 7.6-66.7% of patients. Four studies reported significantly increased cortical excitability (up to 70% of patients). Prolonged central motor conduction time was observed in four studies (30-100% of patients). One study reported absent or prolonged central motor latency in 66.7% of patients. Although MEPs may be abnormal in WD, this has not been thoroughly assessed. Hence, further studies are indispensable to evaluate MEPs' usefulness in assessing pyramidal tract damage in WD.

  1. Comparison of Diffusion Tensor Tractography and Motor Evoked Potentials for the Estimation of Clinical Status in Subacute Stroke.

    Science.gov (United States)

    Chun, Kwang-Soo; Lee, Yong-Taek; Park, Jong-Wan; Lee, Joon-Youn; Park, Chul-Hyun; Yoon, Kyung Jae

    2016-02-01

    To compare diffusion tensor tractography (DTT) and motor evoked potentials (MEPs) for estimation of clinical status in patients in the subacute stage of stroke. Patients with hemiplegia due to stroke who were evaluated using both DTT and MEPs between May 2012 and April 2015 were recruited. Clinical assessments investigated upper extremity motor and functional status. Motor status was evaluated using Medical Research Council grading and the Fugl-Meyer Assessment of upper limb and hand (FMA-U and FMA-H). Functional status was measured using the Modified Barthel Index (MBI). Patients were classified into subgroups according to DTT findings, MEP presence, fractional anisotropy (FA) value, FA ratio (rFA), and central motor conduction time (CMCT). Correlations of clinical assessments with DTT parameters and MEPs were estimated. Fifty-five patients with hemiplegia were recruited. In motor assessments (FMA-U), MEPs had the highest sensitivity and negative predictive value (NPV) as well as the second highest specificity and positive predictive value (PPV). CMCT showed the highest specificity and PPV. Regarding functional status (MBI), FA showed the highest sensitivity and NPV, whereas CMCT had the highest specificity and PPV. Correlation analysis showed that the resting motor threshold (RMT) ratio was strongly associated with motor status of the upper limb, and MEP parameters were not associated with MBI. DTT and MEPs could be suitable complementary modalities for analyzing the motor and functional status of patients in the subacute stage of stroke. The RMT ratio was strongly correlated with motor status.

  2. Influence of sodium hypochlorite treatment of electropolished and magnetoelectropolished nitinol surfaces on adhesion and proliferation of MC3T3 pre-osteoblast cells.

    Science.gov (United States)

    Rokicki, Ryszard; Haider, Waseem; Hryniewicz, Tadeusz

    2012-09-01

    The influence of 6 % sodium hypochlorite (NaClO) treatment on adhesion and proliferation of MC3T3 pre-osteoblast cells seeded on electropolished (EP) and magnetoelectropolished (MEP) nitinol surfaces were investigated. The chemistry, topography, roughness, surface energy, wettability of EP and MEP nitinol surfaces before and after NaClO treatment were studied with X-ray photoelectron spectroscopy (XPS), profilometry, and contact angle meter. In vitro interaction of osteoblast cell and NaClO treated EP and MEP nitinol surfaces were assessed after 3 days of incubation by scanning electron microscopy. The XPS analysis shows that NaClO treatment increases oxygen content especially in subsurface oxide layer of EP and MEP nitinol. The changes of both basic components of nitinol, namely nickel and titanium in oxide layer, were negligible. The NaClO treatment did not influence physico-morphological surface properties of EP and MEP nitinol to a big extent. The osteoblast cells show remarkable adherence and proliferation improvement on NaClO treated EP and MEP nitinol surfaces. After 3 days of incubation they show almost total confluence on both NaClO treated surfaces. The present study shows that NaClO treatment of EP and MEP nitinol surfaces alters oxide layer by enriching it in oxygen and by this improves bone cell-nitinol interaction.

  3. APPLICATION OF MAXIMUM ENTROPY PRINCIPLE METHOD TO THE STUDY OF WAVE CLIMATE STATISTICAL CHARACTERISTICS

    Institute of Scientific and Technical Information of China (English)

    XU Fu-min; XUE Hong-chao

    2004-01-01

    The Maximum Entropy Principle (MEP) method is elaborated, and the corresponding probability density evaluation method for the random fluctuation system is introduced, the goal of the article is to find the best fitting method for the wave climate statistical distribution. For the first time, a kind of new maximum entropy probability distribution (MEP distribution) expression is deduced in accordance with the second order moment of a random process. Different from all the fitting methods in the past, the MEP distribution can describe the probability distribution of any random fluctuation system conveniently and reasonably. If the moments of the random signal is limited to the second order, that is, the ratio of the root-mean-square value to the mean value of the random variable is obtained from the random sample, the corresponding MEP distribution can be computed according to the deduced expression in this essay. The concept of the wave climate is introduced here, and the MEP distribution is applied to fit the probability density distributions of the significant wave height and spectral peak period. Take the Mexico Gulf as an example, three stations at different locations, depths and wind wave strengths are chosen in the half-closed gulf, the significant wave height and spectral peak period distributions at each station are fitted with the MEP distribution, the Weibull distribution and the Log-normal distribution respectively, the fitted results are compared with the field observations, the results show that the MEP distribution is the best fitting method, and the Weibull distribution is the worst one when applied to the significant wave height and spectral peak period distributions at different locations, water depths and wind wave strengths in the Gulf. The conclusion shows the feasibility and reasonability of fitting wave climate statistical distributions with the deduced MEP distributions in this essay, and furthermore proves the great potential of MEP method to

  4. Middle Ear Pressure Regulation - Complementary Action of the Mastoid and Eustachian Tube

    DEFF Research Database (Denmark)

    Gaihede, Michael; Dirckx, Joris J J; Jacobsen, Henrik

    2010-01-01

    HYPOTHESIS:: Middle ear pressure (MEP) is actively regulated by both the Eustachian tube and the mastoid air cell system. BACKGROUND:: MEP is a highly significant factor involved in many clinical conditions related to otitis media. Basic knowledge on its overall regulation remains insufficient...... of these distinct mechanisms were found. CONCLUSION:: The human mastoid as well as the Eustachian tube was capable of active counter-regulation of the MEP in short-term experimental pressure changes in healthy ears. Thus, these 2 systems seemed to function in a complementary way, where the mastoid was related...

  5. Sensory modulation of voluntary and TMS-induced activation in hand muscles.

    Science.gov (United States)

    Kofler, Markus; Valls-Solé, Josep; Fuhr, Peter; Schindler, Christian; Zaccaria, Barbara R; Saltuari, Leopold

    2008-07-01

    Nociceptive suppression of tonic voluntary electromyographic (EMG) activity in human hand muscles (cutaneous silent period, CSP) is in its functional organization consistent with a spinal protective reflex. Motoneuronal excitability and its modulation may also be investigated by conditioned motor evoked potentials (MEPs). To date, effects of exteroceptive stimuli on tonic EMG and on MEPs have been compared mainly using innocuous stimuli, while noxious stimuli have not been studied in great detail. In ten subjects, we recorded CSPs induced in volitionally activated flexor pollicis brevis muscle (FPB) by noxious digit II (D2) stimulation, and in first dorsal interosseous muscle (FDI) following noxious D2 and digit V (D5) stimulation. Then, transcranial magnetic stimulation (TMS) was used to evoke MEPs in the same hand muscles at rest--conditioned by equal noxious D2 or D5 stimulation and individually delayed--so that the MEPs occurred at times corresponding to immediately before, during, and immediately after the CSP in each subject. Immediately before the CSP, there was no significant difference between nociceptive MEP modulation and tonic EMG modulation in any muscle-finger-combination. In the middle of the CSP, noxious finger stimulation exerted suppression of TMS-induced MEPs in all the three muscle-finger-combinations, but less so as compared to corresponding tonic EMG levels. After the CSP, MEPs remained suppressed when corresponding tonic EMG levels were significantly enhanced. Notably, MEPs were also suppressed in cases when occurring at times corresponding to the excitatory long-loop reflex. Incomplete MEP suppression during the CSP may allow for an "emergency grip" even during noxious stimulation. MEP suppression outlasting the CSP is compatible with a "passive" re-synchronization of volitionally activated motor units rather than an "active" reflex involving recruitment of corticospinal motoneurons. The differences in tonic EMG and MEP modulation favors an

  6. Steady state kinetic model for the binding of substrates and allosteric effectors to Escherichia coli phosphoribosyl-diphosphate synthase

    DEFF Research Database (Denmark)

    Willemoës, Martin; Hove-Jensen, Bjarne; Larsen, Sine

    2000-01-01

    saturation with ribose 5-phosphate leads to the binding of Mg2+ and substrates via a slow pathway where Pi binds to the enzyme last. The random mechanism for Pi binding was further supported by studies with competitive inhibitors of Mg2+, MgATP, and ribose 5-phosphate that all appeared noncompetitive when...... varying Pi at either saturating or unsaturating ribose 5-phosphate concentrations. Furthermore, none of the inhibitors induced inhibition at increasing Pi concentrations. Results from ADP inhibition of Pi activation suggest that these effectors compete for binding to a common regulatory site....

  7. Reduced Quadriceps Motor-Evoked Potentials in an Individual with Unilateral Knee Osteoarthritis: A Case Report

    Directory of Open Access Journals (Sweden)

    Michael A. Hunt

    2011-01-01

    Full Text Available One male with unilateral osteoarthritis (OA of the knee underwent testing of corticospinal (CS excitability (as quantified from motor-evoked potentials (MEPs in the rectus femoris (RF using transcranial magnetic stimulation and quadriceps muscle strength. Baseline data indicated reduced MEP amplitudes in the RF of the affected limb compared to the unaffected limb. Increases in RF MEP amplitudes from both limbs were observed immediately following a 30-minute exercise session focusing on muscle strengthening. Following an 8-week muscle strengthening intervention, the participant exhibited increased MEP amplitudes and muscle strength in the affected limb. These findings suggest that alterations in peripheral muscle function found in patients with knee OA may have an origin centrally within the motor cortex and that interlimb differences may be evident in those with unilateral disease. These findings also suggest that CS excitability may be improved following a muscle strengthening intervention.

  8. Startle stimuli exert opposite effects on human cortical and spinal motor system excitability in leg muscles

    DEFF Research Database (Denmark)

    Ilic, T V; Pötter-Nerger, M; Holler, I

    2011-01-01

    Increased excitability of the spinal motor system has been observed after loud and unexpected acoustic stimuli (AS) preceding H-reflexes. The paradigm has been proposed as an electrophysiological marker of reticulospinal tract activity in humans. The brainstem reticular formation also maintains...... (ISI) varied between 20 to 160 ms. When given alone, the test stimulus evoked a MEP amplitude of approximately 0.5 mV in the slightly preinervated soleus muscle (SOL). In the second experiment, the startling AS was used to condition the size of the H-reflex in SOL muscle. Mean MEP amplitude...... was calculated for each ISI. The conditioning AS suppressed MEP amplitude at ISIs of 30-80 ms. By contrast, H-reflex amplitude was augmented at ISIs of 100-200 ms. In conclusions, acoustic stimulation exerts opposite and ISI-specific effects on the amplitude of MEPs and H-reflex in the SOL muscle, indicating...

  9. Connectivity analysis of suggestive brain areas involved in middle ear pressure regulation in humans

    DEFF Research Database (Denmark)

    SA, Sami; Gaihede, Michael

    2010-01-01

    , MEP counter-regulation presented as Eustachian tube openings with steep and fast pressure changes toward 0 Pa, whereas in others, gradual and slow pressure changes presented related to the mastoid; these changes sometimes crossed 0 Pa into opposite pressures. In many cases, combinations......HYPOTHESIS:: Middle ear pressure (MEP) is actively regulated by both the Eustachian tube and the mastoid air cell system. BACKGROUND:: MEP is a highly significant factor involved in many clinical conditions related to otitis media. Basic knowledge on its overall regulation remains insufficient...... of these distinct mechanisms were found. CONCLUSION:: The human mastoid as well as the Eustachian tube was capable of active counter-regulation of the MEP in short-term experimental pressure changes in healthy ears. Thus, these 2 systems seemed to function in a complementary way, where the mastoid was related...

  10. Master environmental plan for Fort Devens, Massachusetts

    Energy Technology Data Exchange (ETDEWEB)

    Biang, C.A.; Peters, R.W.; Pearl, R.H.; Tsai, S.Y. (Argonne National Lab., IL (United States). Energy Systems Div.)

    1991-11-01

    Argonne National Laboratory has prepared a master environmental plan (MEP) for Fort Devens, Massachusetts, for the US Army Toxic and Hazardous Materials Agency. The MEP is an assessment based on environmental laws and regulations of both the federal government and the Commonwealth of Massachusetts. The MEP assess the physical and environmental status of 58 potential hazardous waste sites, including 54 study areas (SAs) that pose a potential for releasing contamination into the environment and 4 areas of concern (AOCs) that are known to have substantial contamination. For each SA or AOC, this MEP describes the known history and environment, identifies additional data needs, and proposes possible response actions. Most recommended response actions consist of environmental sampling and monitoring and other characterization studies. 74 refs., 63 figs., 50 tabs.

  11. 75 FR 19941 - Manufacturing Extension Partnership Advisory Board

    Science.gov (United States)

    2010-04-16

    ... National Institute of Standards and Technology Manufacturing Extension Partnership Advisory Board AGENCY... announces that the Manufacturing Extension Partnership (MEP) Advisory Board, National Institute of Standards..., 2010. FOR FURTHER INFORMATION CONTACT: Karen Lellock, Manufacturing Extension Partnership,...

  12. 77 FR 20790 - Manufacturing Extension Partnership Advisory Board

    Science.gov (United States)

    2012-04-06

    ... National Institute of Standards and Technology Manufacturing Extension Partnership Advisory Board AGENCY... announces that the Manufacturing Extension Partnership (MEP) Advisory Board, National Institute of Standards... INFORMATION section below. FOR FURTHER INFORMATION CONTACT: Karen Lellock, Manufacturing Extension...

  13. 76 FR 22674 - Manufacturing Extension Partnership Advisory Board

    Science.gov (United States)

    2011-04-22

    ... National Institute of Standards and Technology Manufacturing Extension Partnership Advisory Board AGENCY... announces that the Manufacturing Extension Partnership (MEP) Advisory Board, National Institute of Standards... than May 2, 2011. FOR FURTHER INFORMATION CONTACT: Karen Lellock, Manufacturing Extension...

  14. 75 FR 50749 - Manufacturing Extension Partnership Advisory Board

    Science.gov (United States)

    2010-08-17

    ... National Institute of Standards and Technology Manufacturing Extension Partnership Advisory Board AGENCY... announces that the Manufacturing Extension Partnership (MEP) Advisory Board, National Institute of Standards... INFORMATION CONTACT: Karen Lellock, Manufacturing Extension Partnership, National Institute of Standards...

  15. Nanoindentation Studies of TNZ and Ti2448 Biomaterials After Magnetoelectropolishing

    Directory of Open Access Journals (Sweden)

    Hryniewicz T.

    2014-10-01

    Full Text Available This work presents the nanoindentation results of two newly developed titanium alloy biomaterials, TNZ and Ti2448, after different surface treatments. The investigations were performed on the samples, AR – as received, MP – after abrasive polishing, EP – after a standard electropolshing, and MEP – after magnetoelectropolishing. The electropolishing processes, both EP and MEP, were conducted in the same proprietary electrolyte based on concentrated sulfuric acid. The mechanical properties of the titanium alloys biomaterials demonstrated an evident dependence on the surface treatment method, with MEP samples revealing extremely different behaviour and mechanical properties. Such a different mechanical behaviour may mean completely different composition and thickness of the surface film formed on the studied samples after MEP

  16. 15 CFR 291.2 - Environmental integration projects.

    Science.gov (United States)

    2010-01-01

    ... technical assistance to manufacturers. The partnership would lead to greater integration of service delivery... activity, and “customer satisfaction” measures of performance. (5) Management experience and plans... assistance, for smaller manufacturers into the broader services provided by existing MEP...

  17. Medical Expenditure Panel Survey Household Component

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Medical Expenditure Panel Survey (MEPS) Household Component (HC) collects data from a sample of families and individuals in selected communities across the...

  18. Medical Expenditure Panel Survey MEPSnet Insurance Component (MEPSnet/IC)

    Data.gov (United States)

    U.S. Department of Health & Human Services — The MEPS-IC is an annual survey of establishments that collects information about employer-sponsored health insurance offerings in the United States. With MEPSnet/IC...

  19. Bilateral sensory deprivation of trigeminal afferent fibers on corticomotor control of human tongue musculature: A preliminary study

    DEFF Research Database (Denmark)

    Kothari, Mohit; Baad-Hansen, Lene; Svensson, Peter

    2016-01-01

    nerve affects the excitability of the tongue motor cortex (MI) as measured by TMS. Methods: The effect on MEPs after bilateral LA of the lingual nerve was studied, while the first dorsal interosseous (FDI) muscle served as a control in ten healthy participants. MEPs were measured on the right side...... of the tongue dorsum in four different conditions: (1) immediately prior to anaesthesia (baseline), (2) during bilateral LA block of the lingual nerve, (3) after anaesthesia had subjectively subsided (recovery) and (4) 3 hrs after bilateral lingual block injection. MEPs were assessed using stimulus......–response curves in steps of 10% of motor threshold (T). Eight stimuli were given at each stimulus level. Results: The amplitudes of the tongue MEPs were significantly influenced by the stimulus intensity (P

  20. Corticospinal state variability and hemispheric asymmetries in motivational tendencies

    NARCIS (Netherlands)

    Schutter, D.J.L.G.; Hofman, D.; Hoppenbrouwers, S.S.; Kenemans, J.L.

    2011-01-01

    This transcranial magnetic stimulation (TMS) study examined interrelations between asymmetrical hemispheric differences in the degree of variability of corticospinal excitability levels and motivational tendencies. The relative standard deviation in motor evoked potentials (MEP) to single pulse TMS

  1. Gclust Server: 93355 [Gclust Server

    Lifescience Database Archive (English)

    Full Text Available 93355 SCE_YPR138C=MEP3 Cluster Sequences Related Sequences(238) 489 Ammonium permease of high capacity...s(238) Sequence length 489 Representative annotation Ammonium permease of high capacity

  2. Green Supplier Network Manufacturer Commitment Form

    Science.gov (United States)

    Online form expressing interest in committing to be a Green Supplier; this form expresses your intent to participate in a confidential Green Suppliers Network assessment, implement recommended environmental improvements and complete a NIST MEP follow-up.

  3. Present and Last Glacial Maximum climates as states of maximum entropy production

    CERN Document Server

    Herbert, Corentin; Kageyama, Masa; Dubrulle, Berengere

    2011-01-01

    The Earth, like other planets with a relatively thick atmosphere, is not locally in radiative equilibrium and the transport of energy by the geophysical fluids (atmosphere and ocean) plays a fundamental role in determining its climate. Using simple energy-balance models, it was suggested a few decades ago that the meridional energy fluxes might follow a thermodynamic Maximum Entropy Production (MEP) principle. In the present study, we assess the MEP hypothesis in the framework of a minimal climate model based solely on a robust radiative scheme and the MEP principle, with no extra assumptions. Specifically, we show that by choosing an adequate radiative exchange formulation, the Net Exchange Formulation, a rigorous derivation of all the physical parameters can be performed. The MEP principle is also extended to surface energy fluxes, in addition to meridional energy fluxes. The climate model presented here is extremely fast, needs very little empirical data and does not rely on ad hoc parameterizations. We in...

  4. Motor skill training and strength training are associated with different plastic changes in the central nervous system

    DEFF Research Database (Denmark)

    Jensen, Jesper Lundbye; Marstrand, Peter C.D.; Nielsen, Jens Bo

    2005-01-01

    performing skill training. With repeated skill training three times per week for 4 wk, MEPmax increased and the minimal stimulation intensity required to elicit MEPs decreased significantly at rest and during contraction (P

  5. Recurrent rearrangement during adaptive evolution in an interspecific yeast hybrid suggests a model for rapid introgression.

    Directory of Open Access Journals (Sweden)

    Barbara Dunn

    2013-03-01

    Full Text Available Genome rearrangements are associated with eukaryotic evolutionary processes ranging from tumorigenesis to speciation. Rearrangements are especially common following interspecific hybridization, and some of these could be expected to have strong selective value. To test this expectation we created de novo interspecific yeast hybrids between two diverged but largely syntenic Saccharomyces species, S. cerevisiae and S. uvarum, then experimentally evolved them under continuous ammonium limitation. We discovered that a characteristic interspecific genome rearrangement arose multiple times in independently evolved populations. We uncovered nine different breakpoints, all occurring in a narrow ~1-kb region of chromosome 14, and all producing an "interspecific fusion junction" within the MEP2 gene coding sequence, such that the 5' portion derives from S. cerevisiae and the 3' portion derives from S. uvarum. In most cases the rearrangements altered both chromosomes, resulting in what can be considered to be an introgression of a several-kb region of S. uvarum into an otherwise intact S. cerevisiae chromosome 14, while the homeologous S. uvarum chromosome 14 experienced an interspecific reciprocal translocation at the same breakpoint within MEP2, yielding a chimaeric chromosome; these events result in the presence in the cell of two MEP2 fusion genes having identical breakpoints. Given that MEP2 encodes for a high-affinity ammonium permease, that MEP2 fusion genes arise repeatedly under ammonium-limitation, and that three independent evolved isolates carrying MEP2 fusion genes are each more fit than their common ancestor, the novel MEP2 fusion genes are very likely adaptive under ammonium limitation. Our results suggest that, when homoploid hybrids form, the admixture of two genomes enables swift and otherwise unavailable evolutionary innovations. Furthermore, the architecture of the MEP2 rearrangement suggests a model for rapid introgression, a

  6. Evidence for two concurrent inhibitory mechanisms during response preparation

    OpenAIRE

    Duque, Julie; Lew, David; Mazzocchio, Riccardo; Olivier, Etienne; Ivry, Richard B.

    2010-01-01

    Inhibitory mechanisms are critically involved in goal-directed behaviors. To gain further insight into how such mechanisms shape motor representations during response preparation, motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS) and H-reflexes were recorded from left hand muscles during choice reaction time tasks. The imperative signal, which indicated the required response, was always preceded by a preparatory cue. During the post-cue delay period, left MEPs...

  7. Differences in motor evoked potentials induced in rats by transcranial magnetic stimulation under two separate anesthetics: implications for plasticity studies

    Directory of Open Access Journals (Sweden)

    Matthew Sykes

    2016-10-01

    Full Text Available Repetitive transcranial magnetic stimulation (rTMS is primarily used in humans to change the state of corticospinal excitability. To assess the efficacy of different rTMS stimulation protocols, motor evoked potentials (MEPs are used as a readout due to their non-invasive nature. Stimulation of the motor cortex produces a response in a targeted muscle, and the amplitude of this twitch provides an indirect measure of the current state of the cortex. When applied to the motor cortex, rTMS can alter MEP amplitude, however results are variable between participants and across studies. In addition, the mechanisms underlying any change and its locus are poorly understood. In order to better understand these effects, MEPs have been investigated in vivo in animal models, primarily in rats. One major difference in protocols between rats and humans is the use of general anesthesia in animal experiments. Anesthetics are known to affect plasticity-like mechanisms and so may contaminate the effects of an rTMS protocol. In the present study, we explored the effect of anesthetic on MEP amplitude, recorded before and after intermittent theta burst stimulation (iTBS, a patterned rTMS protocol with reported facilitatory effects. MEPs were assessed in the brachioradialis muscle of the upper forelimb under two anesthetics: a xylazine/zoletil combination and urethane. We found MEPs could be induced under both anesthetics, with no differences in the resting motor threshold or the average baseline amplitudes. However, MEPs were highly variable between animals under both anesthetics, with the xylazine/zoletil combination showing higher variability and most prominently a rise in amplitude across the baseline recording period. Interestingly, application of iTBS did not facilitate MEP amplitude under either anesthetic condition. Although it is important to underpin human application of TMS with mechanistic examination of effects in animals, caution must be taken when

  8. Building Information Modeling (BIM) Primer. Report 1: Facility Life-Cycle Process and Technology Innovation

    Science.gov (United States)

    2012-08-01

    there plans to maintain the delivered BIM c. What format are the BIM in (Revit, AutoCAD , Bentley) d. What standards are in place for BIM...tively. The solution is to integrate design Web format (DWF) capabilities with AutoCAD software to give customers access to spatial information contained...Structure, Autodesk Revit MEP, Autodesk Navisworks Manage, AutoCAD MEP, Autodesk Civil 3D Project Budget Reasonable, able to achieve by using student

  9. Analysis of Rotary Aircraft Alternatives for NATO SOF Organic Air Wing

    Science.gov (United States)

    2012-06-01

    the Guidelines for NATO SOF Helicopter Operations,41 the primary skill sets include: (a) Advanced Night Vision Goggle ( NVG ) flying, including NVG ... Helicopter MA Military Assistance MEP(s) Mission Essential Package(s) MFP Multiple Futures Project MTTR Mean Time To Repair NATO North Atlantic...NATO Special Operations Coordination Center NVG Night Vision Goggle O&S Operation and Support OMB Office of Management and Budget SACEUR

  10. National Airspace Review Benefits and Costs.

    Science.gov (United States)

    1984-04-01

    engine The APO study describes the following costs.’ 5 piston (MEP) and turboprop (TP), respectively. Furthermore, FAA estimates the value of time Task...aircraft flown by these operators, the average "On the basis of previously provided Stage Ill weighted GA operator value of time per hour TRSA services, it...engine The APO study describes the following costs.15 piston (MEP) and turboprop (TP), respectively. Furthermore, FAA estimates the value of time Task

  11. Counterintelligence Screening Needed lo Reduce Security Threat That Unscreened Local National Linguists Pose to U.S. Forces (REDACTED)

    Science.gov (United States)

    2012-12-07

    Logistics Civil Augmentation Program MEP Mission Essential Personnel MFR Memorandum for Record OCI Organizational Conflict of Interest OCONUS Outside...reports would draw conclusions and recollllllel1dations on the retention, hir.ing, or threat posed by the LNs. MEP would send thjl MFRs to tlie...office responsible for issning badges on the local installations if the MFRs had no negative CI infonnation. If the MFRs had CI exploitable information

  12. Visualization of the electric field evoked by transcranial electric stimulation during a craniotomy using the finite element method.

    Science.gov (United States)

    Tomio, Ryosuke; Akiyama, Takenori; Horikoshi, Tomo; Ohira, Takayuki; Yoshida, Kazunari

    2015-12-30

    Transcranial MEP (tMEP) monitoring is more readily performed than cortical MEP (cMEP), however, tMEP is considered as less accurate than cMEP. The craniotomy procedure and changes in CSF levels must affect current spread. These changes can impair the accuracy. The aim of this study was to investigate the influence of skull deformation and cerebrospinal fluid (CSF) decrease on tMEP monitoring during frontotemporal craniotomy. We used the finite element method to visualize the electric field in the brain, which was generated by transcranial electric stimulation, using realistic 3-dimensional head models developed from T1-weighted images. Surfaces of 5 layers of the head were separated as accurately as possible. We created 3 brain types and 5 craniotomy models. The electric field in the brain radiates out from the cortex just below the electrodes. When the CSF layer is thick, a decrease in CSF volume and depression of CSF surface level during the craniotomy has a major impact on the electric field. When the CSF layer is thin and the distance between the skull and brain is short, the craniotomy has a larger effect on the electric field than the CSF decrease. So far no report in the literature the electric field during intraoperative tMEP using a 3-dimensional realistic head model. Our main finding was that the intensity of the electric field in the brain is most affected by changes in the thickness and volume of the CSF layer. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Estimate of Technical Potential for Minimum Efficiency Performance Standards in 13 Major World Economies

    Energy Technology Data Exchange (ETDEWEB)

    Letschert, Virginie [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Desroches, Louis-Benoit [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Ke, Jing [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); McNeil, Michael [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2012-07-01

    As part of the ongoing effort to estimate the foreseeable impacts of aggressive minimum efficiency performance standards (MEPS) programs in the world’s major economies, Lawrence Berkeley National Laboratory (LBNL) has developed a scenario to analyze the technical potential of MEPS in 13 major economies around the world1 . The “best available technology” (BAT) scenario seeks to determine the maximum potential savings that would result from diffusion of the most efficient available technologies in these major economies.

  14. Change in Excitability of Corticospinal Pathway and GABA-Mediated Inhibitory Circuits of Primary Motor Cortex Induced by Contraction of Adjacent Hand Muscle.

    Science.gov (United States)

    Jono, Yasutomo; Iwata, Yasuyuki; Mizusawa, Hiroki; Hiraoka, Koichi

    2016-11-01

    The present study examined whether the excitability of the corticospinal pathway and the GABA-mediated inhibitory circuits of the primary motor cortex that project onto the corticospinal neurons in the tonically contracting hand muscle are changed by tonic contraction of the adjacent hand muscle. The motor evoked potential (MEP) and cortical silent period (CSP) in the tonically contracting hand muscle were obtained while the adjacent hand muscle was either tonically contracting or at rest. The MEP and CSP of the first dorsal interosseous (FDI) muscle elicited across the scalp sites where the MEP is predominantly elicited in the FDI muscle were decreased by tonic contraction of the abductor digiti minimi (ADM) muscle. The centers of the area of the MEP and the duration of the CSP in the FDI muscle elicited across the sites where the MEP is predominantly elicited in the FDI muscle were lateral to those in the FDI muscle elicited across the sites where the MEP is elicited in both the FDI and ADM muscles. They were also lateral to those in the ADM muscle elicited either across the sites where the MEP is predominantly elicited in the ADM muscle, or across the sites where the MEP is elicited in both the FDI and ADM muscles. The decrease in the corticospinal excitability and the excitability of the GABA-mediated inhibitory circuits of the primary motor cortex that project onto the corticospinal neurons in the FDI muscle may be due either to (1) the interaction between the activity of the lateral area of the FDI representation and the descending drive to the ADM muscle, or (2) the decreased susceptibility of the primary motor area that predominantly projects onto the corticospinal neurons in the FDI muscle, which also plays a role in independent finger movement when both the FDI and ADM muscles act together as synergists.

  15. Relaxation from a voluntary contraction is preceded by increased excitability of motor cortical inhibitory circuits.

    Science.gov (United States)

    Buccolieri, Alessandro; Abbruzzese, Giovanni; Rothwell, John C

    2004-07-15

    Termination of a muscle contraction is as important a part of movement as muscle activation yet the mechanisms responsible are less well understood. In the present experiments we examined the possible role of intracortical inhibitory circuits in terminating a 20% maximum isometric contraction of the first dorsal interosseous muscle (FDI) in eight healthy subjects. Subjects performed the task simultaneously with both hands and received single or pairs (at an interstimulus interval of 3 ms to evaluate short interval intracortical inhibition, SICI) of transcranial magnetic stimuli (TMS) via a focal coil over the motor hand area of the left hemisphere at different times before and after the onset of relaxation. The amplitude of the motor-evoked potential (MEP) following a single or a pair of TMS pulses was measured in the right FDI and plotted relative to the onset of relaxation as estimated from the surface electromyogram (EMG) of the left FDI. MEPs were larger during contraction than after relaxation whereas SICI was absent during contraction and reappeared after relaxation. We found that in all subjects, the time course of MEP changes during relaxation was closely fitted by a Boltzmann sigmoidal curve which allowed us to estimate the mean MEP amplitudes as well as the ratio of the amplitudes after single or pairs of TMS pulses (i.e.%SICI) at any time in the task. The data showed that the amplitude of MEPs to single pulse TMS had started to decline at about the same time as the onset of EMG silence. Furthermore, the size of the MEPs evoked by paired pulses decreased up to 30 ms beforehand. The latter suggests that an increase in SICI occurs prior to the onset of MEP changes, and hence that increased cortical inhibition may play a role in suppressing corticospinal excitability during relaxation. A subsidiary experiment showed that the time relations of changes in SICI and MEP were unchanged by a period of 10 min training on the task.

  16. Estimate of Technical Potential for Minimum Efficiency Performance Standards in 13 Major World Economies

    Energy Technology Data Exchange (ETDEWEB)

    Letschert, Virginie [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Desroches, Louis-Benoit [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Ke, Jing [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); McNeil, Michael [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2012-07-01

    As part of the ongoing effort to estimate the foreseeable impacts of aggressive minimum efficiency performance standards (MEPS) programs in the world’s major economies, Lawrence Berkeley National Laboratory (LBNL) has developed a scenario to analyze the technical potential of MEPS in 13 major economies around the world1 . The “best available technology” (BAT) scenario seeks to determine the maximum potential savings that would result from diffusion of the most efficient available technologies in these major economies.

  17. Cortical Reorganization Is Associated with Surgical Decompression of Cervical Spondylotic Myelopathy

    Directory of Open Access Journals (Sweden)

    Andrew Green

    2015-01-01

    Full Text Available Background. Cervical spondylotic myelopathy (CSM results in sensorimotor limb deficits, bladder, and bowel dysfunction, but mechanisms underlying motor plasticity changes before and after surgery are unclear. Methods. We studied 24 patients who underwent decompression surgery and 15 healthy controls. Patients with mixed upper and lower limb dysfunction (Group A and only lower limb dysfunction (Group B were then analysed separately. Results. The sum amplitude of motor evoked potentials sMEP (p<0.01 and number of focal points where MEPs were elicited (N (p<0.001 were significantly larger in CSM patients compared with controls. For Group A (16 patients, sMEP (p<0.01 and N (p<0.001 showed similar findings. However, for Group B (8 patients, only N (p=0.03 was significantly larger in patients than controls. Group A had significantly increased grip strength (p=0.02 and reduced sMEP (p=0.001 and N (p=0.003 after surgery. Changes in sMEP (cMEP significantly correlated inversely with improved feeding (p=0.03 and stacking (p=0.04 times as was the change in number of focal points (NDiff with improved writing times (p=0.03. Group B did not show significant reduction in sMEP or N after surgery, or significant correlation of cMEP or NDiff with all hand function tests. No significant differences in H reflex parameters obtained from the flexor carpi radialis, or central motor conduction time changes, were noted after surgery. Discussion. Compensatory expansion of motor cortical representation occurs largely at cortical rather than spinal levels, with a tendency to normalization after surgery. These mirrored improvements in relevant tasks requiring utilization of intrinsic hand muscles.

  18. Comparative Sensitivity of Intraoperative Motor Evoked Potential Monitoring in Predicting Postoperative Neurologic Deficits: Nondegenerative versus Degenerative Myelopathy.

    Science.gov (United States)

    Clark, Aaron J; Safaee, Michael; Chou, Dean; Weinstein, Philip R; Molinaro, Annette M; Clark, John P; Mummaneni, Praveen V

    2016-08-01

    Retrospective review. Intraoperative motor evoked potential (MEP) monitoring in spine surgery may assist surgeons in taking corrective measures to prevent neurologic deficits. The efficacy of monitoring MEPs intraoperatively in patients with myelopathy from nondegenerative causes has not been quantified. We compared the sensitivity and specificity of intraoperative MEP monitoring in patients with myelopathy caused by nondegenerative processes to patients with degenerative cervicothoracic spondylotic myelopathy (CSM). We retrospectively reviewed our myelopathy surgical cases during a 1-year period to identify patients with degenerative CSM and CSM of nondegenerative causes and collected data on intraoperative MEP changes and postoperative new deficits. Categorical variables were analyzed by Fisher exact test. Receiver operator curves assessed intraoperative MEP monitoring performance in the two groups. In all, 144 patients were identified: 102 had degenerative CSM and 42 had CSM of nondegenerative causes (24 extra-axial tumors, 12 infectious processes, 5 traumatic fractures, and 1 rheumatoid arthritis). For degenerative CSM, there were 11 intraoperative MEP alerts and 7 new deficits (p sensitivity was 71% and the specificity was 94%. In the nondegenerative group, there were 11 intraoperative MEP alerts and 3 deficits, which was not significant (p > 0.99). The sensitivity (33%) and specificity (74%) were lower. Among patients with degenerative CSM, the model performed well for predicting postoperative deficits (area under the curve [AUC] 0.826), which appeared better than the nondegenerative group, although it did not reach statistical significance (AUC 0.538, p = 0.16). Based on this large retrospective analysis, intraoperative MEP monitoring in surgery for nondegenerative CSM cases appears to be less sensitive to cord injury and less predictive of postoperative deficits when compared with degenerative CSM cases.

  19. Excitability of the Primary Motor Cortex Increases More Strongly with Slow- than with Normal-Speed Presentation of Actions

    OpenAIRE

    Takefumi Moriuchi; Naoki Iso; Akira Sagari; Kakuya Ogahara; Eiji Kitajima; Koji Tanaka; Takayuki Tabira; Toshio Higashi

    2014-01-01

    Introduction: The aim of the present study was to investigate how the speed of observed action affects the excitability of the primary motor cortex (M1), as assessed by the size of motor evoked potentials (MEPs) induced by transcranial magnetic stimulation (TMS). Copyright: Methods: Eighteen healthy subjects watched a video clip of a person catching a ball, played at three different speeds (normal-, half-, and quarter-speed). MEPs were induced by TMS when the model's hand had opened to the...

  20. Analysis of facial motor evoked potentials for assessing a central mechanism in hemifacial spasm.

    Science.gov (United States)

    Wilkinson, Marshall F; Chowdhury, Tumul; Mutch, W Alan; Kaufmann, Anthony M

    2017-02-01

    OBJECTIVE Hemifacial spasm (HFS) is a cranial nerve hyperactivity disorder characterized by unique neurophysiological features, although the underlying pathophysiology remains disputed. In this study, the authors compared the effects of desflurane on facial motor evoked potentials (MEPs) from the spasm and nonspasm sides of patients who were undergoing microvascular decompression (MVD) surgery to test the hypothesis that HFS is associated with a central elevation of facial motor neuron excitability. METHODS Facial MEPs were elicited in 31 patients who were undergoing MVD for HFS and were administered total intravenous anesthesia (TIVA) with or without additional desflurane, an inhaled anesthetic known to centrally suppress MEPs. All measurements were completed before dural opening while a consistent mean arterial blood pressure was maintained and electroencephalography was performed. The activation threshold voltage and mean amplitudes of the MEPs from both sides of the face were compared. RESULTS There was a significantly lower mean activation threshold of facial MEPs on the spasm side than on the nonspasm side (mean ± SD 162.9 ± 10.1 vs 198.3 ± 10.1 V, respectively; p = 0.01). In addition, MEPs were also elicited more readily when single-pulse transcranial electrical stimulation was used on the spasm side (74% vs 31%, respectively; p = 0.03). Although desflurane (1 minimum alveolar concentration) suppressed facial MEPs on both sides, the suppressive effects of desflurane were less on the spasm side than on the nonspasm side (59% vs 79%, respectively; p = 0.03), and M waves recorded from the mentalis muscle remained unchanged, which indicates that desflurane did not affect the peripheral facial nerve or neuromuscular junction. CONCLUSIONS Centrally acting inhaled anesthetic agents can suppress facial MEPs and therefore might interfere with intraoperative monitoring. The elevated motor neuron excitability and differential effects of desflurane between the spasm

  1. HIGH-VOLUME RESISTANCE TRAINING SESSION ACUTELY DIMINISHES RESPIRATORY MUSCLE STRENGTH

    Directory of Open Access Journals (Sweden)

    Daniel A. Hackett

    2012-03-01

    Full Text Available This study investigated the effect of a high-volume compared to a low-volume resistance training session on maximal inspiratory pressure (MIP and maximal expiratory pressure (MEP. Twenty male subjects with resistance training experience (6.2 ± 3.2 y, in a crossover trial, completed two resistance training protocols (high-volume: 5 sets per exercise; low-volume: 2 sets per exercise and a control session (no exercise on 3 separate occasions. MIP and MEP decreased by 13.6% (p < 0.01 and 14.7% (p < 0.01 respectively from pre-session MIP and MEP, following the high-volume session. MIP and MEP were unaffected following the low-volume or the control sessions. MIP returned to pre-session values after 40 minutes, whereas MEP remained significantly reduced after 60 minutes post-session by 9.2% compared to pre-session (p < 0.01. The findings suggest that the high-volume session significantly decreased MIP and MEP post-session, implicating a substantially increased demand on the respiratory muscles and that adequate recovery is mandatory following this mode of training.

  2. Differentiation of sensorimotor neuronal structures responsible for induction of motor evoked potentials, attenuation in detection of somatosensory stimuli, and induction of sensation of movement by mapping of optimal current directions.

    Science.gov (United States)

    Pascual-Leone, A; Cohen, L G; Brasil-Neto, J P; Valls-Solé, J; Hallett, M

    1994-06-01

    Transcranial magnetic stimulation (TMS) of the sensorimotor cortex can evoke motor evoked potentials (MEPs), attenuation in detection of somatosensory stimuli (ADSS), and sensation of movement (SOM) referred to the same body part. In this study we tried to differentiate the substrates responsible for these effects. In 6 normal volunteers, TMS was applied with a nearly monopolar Dantec stimulator and a butterfly coil. Optimal scalp location and current direction were determined for induction of MEPs in abductor pollicis brevis (APB), first dorsal interosseous (FDI), and adductor digiti minimi (ADM); SOM in digits 2 and 5 in an ischemically paralyzed hand; and ADSS applied to digits 2 and 5. All 3 muscles' MEPs and SOM and ADSS in both digits were optimally activated from a single scalp position. In all subjects, optimal current directions for MEPs pointed anteriorly; those for ADSS and SOM pointed posteriorly. Optimal current directions showed the same progression in all subjects for MEPs (ADM, FDI, and APB from antero-lateral to antero-medial), ADSS (digit 5 postero-medial, 2 postero-lateral), and SOM (digit 1 through 5 postero-lateral to postero-medial). We conclude that neuronal networks targeting corticospinal neurons responsible for MEPs are different from those leading to SOM and ADSS (which could not be differentiated).

  3. Scaling of motor cortical excitability during unimanual force generation.

    Science.gov (United States)

    Perez, Monica A; Cohen, Leonardo G

    2009-10-01

    During performance of a unimanual force generation task primary motor cortices (M1s) experience clear functional changes. Here, we evaluated the way in which M1s interact during parametric increases in right wrist flexion force in healthy volunteers. We measured the amplitude and the slope of motor evoked potentials (MEP) recruitment curves to transcranial magnetic stimulation (TMS) in the left and right flexor carpi radialis (FCR) muscles at rest and during 10%, 30% and 70% of maximal wrist flexion force. At rest, no differences were observed in the amplitude and slope of MEP recruitment curves in the left and right FCR muscles. With increasing right wrist flexion force, MEP amplitudes increased in both FCR muscles, with larger amplitudes in the right FCR. We found a significant correlation between the left and right MEP amplitudes across conditions. The slope of right and left FCR MEP recruitment curve was significantly steeper at 70% of force compared to rest and 10% of force. A significant correlation between the slope of left and right FCR MEP amplitudes was found at 70% of force only. Our results indicate a differential scaling of excitability in the corticospinal system controlling right and left FCR muscles at increasing levels of unimanual force generation. Specifically, these data highlights that at strong levels of unimanual force the increases in motor cortical excitability with increasing TMS stimulus intensities follow a similar pattern in both M1s, while at low levels of force they do not.

  4. Maximum entropy production and the fluctuation theorem

    Energy Technology Data Exchange (ETDEWEB)

    Dewar, R C [Unite EPHYSE, INRA Centre de Bordeaux-Aquitaine, BP 81, 33883 Villenave d' Ornon Cedex (France)

    2005-05-27

    Recently the author used an information theoretical formulation of non-equilibrium statistical mechanics (MaxEnt) to derive the fluctuation theorem (FT) concerning the probability of second law violating phase-space paths. A less rigorous argument leading to the variational principle of maximum entropy production (MEP) was also given. Here a more rigorous and general mathematical derivation of MEP from MaxEnt is presented, and the relationship between MEP and the FT is thereby clarified. Specifically, it is shown that the FT allows a general orthogonality property of maximum information entropy to be extended to entropy production itself, from which MEP then follows. The new derivation highlights MEP and the FT as generic properties of MaxEnt probability distributions involving anti-symmetric constraints, independently of any physical interpretation. Physically, MEP applies to the entropy production of those macroscopic fluxes that are free to vary under the imposed constraints, and corresponds to selection of the most probable macroscopic flux configuration. In special cases MaxEnt also leads to various upper bound transport principles. The relationship between MaxEnt and previous theories of irreversible processes due to Onsager, Prigogine and Ziegler is also clarified in the light of these results. (letter to the editor)

  5. Ipsilesional motor-evoked potential absence in pediatric hemiparesis impacts tracking accuracy of the less affected hand.

    Science.gov (United States)

    Cassidy, Jessica M; Carey, James R; Lu, Chiahao; Krach, Linda E; Feyma, Tim; Durfee, William K; Gillick, Bernadette T

    2015-12-01

    This study analyzed the relationship between electrophysiological responses to transcranial magnetic stimulation (TMS), finger tracking accuracy, and volume of neural substrate in children with congenital hemiparesis. Nineteen participants demonstrating an ipsilesional motor-evoked potential (MEP) were compared with eleven participants showing an absent ipsilesional MEP response. Comparisons of finger tracking accuracy from the affected and less affected hands and ipsilesional/contralesional (I/C) volume ratio for the primary motor cortex (M1) and posterior limb of internal capsule (PLIC) were done using two-sample t-tests. Participants showing an ipsilesional MEP response demonstrated superior tracking performance from the less affected hand (p=0.016) and significantly higher I/C volume ratios for M1 (p=0.028) and PLIC (p=0.005) compared to participants without an ipsilesional MEP response. Group differences in finger tracking accuracy from the affected hand were not significant. These results highlight differentiating factors amongst children with congenital hemiparesis showing contrasting MEP responses: less affected hand performance and preserved M1 and PLIC volume. Along with MEP status, these factors pose important clinical implications in pediatric stroke rehabilitation. These findings may also reflect competitive developmental processes associated with the preservation of affected hand function at the expense of some function in the less affected hand. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. ‘Normal Parliament’: Exploring the Organisation of Everyday Political Life in an MEP’s Office

    Directory of Open Access Journals (Sweden)

    Amy Busby

    2013-02-01

    Full Text Available The Lisbon Treaty has again enhanced the role and powers of the European Parliament [EP] and therefore increased the workload of individual MEPs. However many citizens remain unaware of what MEPs do and how they represent them. This paper reviews the academic literature and argues that we need to know more about how individual MEPs practise European politics inside this institution. Throughout, it argues that ethnography can play a key role in opening up this institutional black-box and enhancing our understanding of this profession by focusing on daily activities and backstage processes. It begins by exploring the working environment of MEPs, which is characterised by shortage of time, constant travelling, information overload, and highly technical issues. Secondly, it describes strategies MEPs employ to pursue their aims here, namely: specialisation, filtering, employing assistants, and information management. Thirdly, it draws comparisons with other professional fields to remind us the EP is a normal professional work environment. The contributions are twofold: the article provides a deeper, more nuanced, and more holistic understanding of (individual MEP behaviour; and also helps to demystify the profession and thus help alleviate the democratic deficit by beginning to close the gap between politicians and citizens.

  7. Selective proliferation of human γδ T cells in vitro

    Institute of Scientific and Technical Information of China (English)

    CHENSONGHUA; AKINORIOKI; 等

    1996-01-01

    The effect of monoethylphosphate (MEP,commercial available or synthesized) together with IL-2 on the selective proliferation of human γδT cells in vitro from peripheral blood mononuclear cells (PBMC) of healthy donors and of cancer patients was investigated.The γδT cells were stimulated by MEP to proliferate in a dose-dependent manner.The effect of synthesized MEP was 10 times greater than that of commercial MEP.When the PBMCs of healthy donors were cultured for 25 d in the medium containing different concentrations of MEP,the total cell number increased about 1000-3000 fold;and the ratio of γδT cells reached to 70-80%.The selective expansion of γδT cells depended on the synergic action of MEP and IL-2.The bulk cultured γδT cells exhibited obvious cytotoxic activities against allogenic tumor cell lines (SQ-5,K562 and Daudi) and autologous tumor cells.The culture system described here not only offers a simple method for obtaining a large number of γδT cells which may become a new effector in the adoptive immunotherapy,but also provides a useful model for the further studies of the structure and function of γδT cells in vitro.

  8. Updated U.S. population standard for the Veterans RAND 12-item Health Survey (VR-12).

    Science.gov (United States)

    Selim, Alfredo J; Rogers, William; Fleishman, John A; Qian, Shirley X; Fincke, Benjamin G; Rothendler, James A; Kazis, Lewis E

    2009-02-01

    The purpose of this project was to develop an updated U.S. population standard for the Veterans RAND 12-item Health Survey (VR-12). We used a well-defined and nationally representative sample of the U.S. population from 52,425 responses to the Medical Expenditure Panel Survey (MEPS) collected between 2000 and 2002. We applied modified regression estimates to update the non-proprietary 1990 scoring algorithms. We applied the updated standard to the Medicare Health Outcomes Survey (HOS) to compute the VR-12 physical (PCS((MEPS standard))) and mental (MCS((MEPS standard))) component summaries based on the MEPS. We compared these scores to PCS and MCS based on the 1990 U.S. population standard. Using the updated U.S. population standard, the average VR-12 PCS((MEPS standard)) and MCS((MEPS standard)) scores in the Medicare HOS were 39.82 (standard deviation [SD] = 12.2) and 50.08 (SD = 11.4), respectively. For the same Medicare HOS, the average PCS and MCS scores based on the 1990 standard were 1.40 points higher and 0.99 points lower in comparison to VR-12 PCS and MCS, respectively. Changes in the U.S. population between 1990 and today make the old standard obsolete for the VR-12, so the updated standard developed here is widely available to serve as such a contemporary standard for future applications for health-related quality of life (HRQoL) assessments.

  9. Repeated tongue lift movement induces neuroplasticity in corticomotor control of tongue and jaw muscles in humans.

    Science.gov (United States)

    Komoda, Yoshihiro; Iida, Takashi; Kothari, Mohit; Komiyama, Osamu; Baad-Hansen, Lene; Kawara, Misao; Sessle, Barry; Svensson, Peter

    2015-11-19

    This study investigated the effect of repeated tongue lift training (TLT) on the excitability of the corticomotor representation of the human tongue and jaw musculature. Sixteen participants performed three series of TLT for 41 min on each of 5 consecutive days. Each TLT series consisted of two pressure levels (5 kPa and 10 kPa). All participants underwent transcranial magnetic stimulation (TMS) and electromyographic (EMG) recordings of motor evoked potentials (MEPs) in four sessions: (1) before TLT on Day 1 (baseline), (2) after TLT on Day 1, (3) before TLT on Day 5, and (4) after TLT on Day 5. EMG recordings from the left and right tongue dorsum and masseter muscles were made at three pressure levels (5 kPa, 10 kPa, 100% tongue lift), and tongue, masseter, and first dorsal interosseous (FDI) MEPs were measured. There were no significant day-to-day differences in the tongue pressure during maximum voluntary contractions. The amplitudes and thresholds of tongue and masseter MEPs after TLT on Day 5 were respectively higher and lower than before TLT on Day 1 (Ptongue and masseter MEP areas; no significant changes occurred in MEP onset latencies. FDI MEP parameters (amplitude, threshold, area, latency) were not significantly different between the four sessions. Our findings suggest that repeated TLT can trigger neuroplasticity reflected in increased excitability of the corticomotor representation of not only the tongue muscles but also the masseter muscles.

  10. Proposal Intensity Adequacy of Expiratory Effort and Heart Rate Behavior During the Valsalva Maneuver in Preadolescents

    Directory of Open Access Journals (Sweden)

    Mario Augusto Paschoal

    2014-08-01

    Full Text Available Background: When performing the Valsalva maneuver (VM, adults and preadolescents produce the same expiratory resistance values. Objective: To analyze heart rate (HR in preadolescents performing VM, and propose a new method for selecting expiratory resistance. Method: The maximal expiratory pressure (MEP was measured in 45 sedentary children aged 9-12 years who subsequently performed VM for 20 s using an expiratory pressure of 60%, 70%, or 80% of MEP. HR was measured before, during, and after VM. These procedures were repeated 30 days later, and the data collected in the sessions (E1, E2 were analyzed and compared in periods before, during (0-10 and 10-20 s, and after VM using nonparametric tests. Results: All 45 participants adequately performed VM in E1 and E2 at 60% of MEP. However, only 38 (84.4% and 25 (55.5% of the participants performed the maneuver at 70% and 80% of MEP, respectively. The HR delta measured during 0-10 s and 10-20 s significantly increased as the expiratory effort increased, indicating an effective cardiac autonomic response during VM. However, our findings suggest the VM should not be performed at these intensities. Conclusion: HR increased with all effort intensities tested during VM. However, 60% of MEP was the only level of expiratory resistance that all participants could use to perform VM. Therefore, 60% of MEP may be the optimal expiratory resistance that should be used in clinical practice.

  11. The role of cutaneous inputs during magnetic transcranial stimulation.

    Science.gov (United States)

    Rossini, P M; Tecchio, F; Sabato, A; Finazzi-Agrò, A; Pasqualetti, P; Rossi, S

    1996-10-01

    Latency and amplitude characteristics of motor evoked potentials (MEPs) from abductor digiti minimi (ADM) and first dorsal interosseus (FDI) muscles were evaluated in 7 healthy volunteers via magnetic transcranial stimulation of the hemiscalp overlying contralateral motor areas. MEPs in complete relaxation and during contraction were recorded in two different experimental conditions: before and following anesthesia of median (sensory + motor) and radial (sensory) nerve fibers at wrist. This procedure induced a complete loss of skin sensation from dorsal and palmar aspects of the hand area "enveloping" the FDI muscle. On the other hand, the skin overlying the ADM muscle, as well as the strength of ulnar nerve supplied muscles were spared. This selective sensory deprivation lead to the following short-term changes: the physiological latency "jump" toward shorter values in contracted MEPs vs. relaxation was partially lost in the FDI (3.0 +/- 1.4 ms in basal condition, 1.8 +/- 1.1 ms after anesthesia, P = 0.028), while it was still clearly evident in the ADM (3.7 +/- 0.9 ms and 3.3 +/- 1.0 ms, respectively). Moreover, minor amplitude changes of MEPs during active contraction in the two muscles were detected: MEPs recorded from the FDI muscle were less potentiated during voluntary contraction than those recorded from the ADM muscle. The role of the cutaneous input in governing latency/amplitude characteristics of MEPs is discussed.

  12. Protein: MPA5 [TP Atlas

    Lifescience Database Archive (English)

    Full Text Available MPA5 Pyrimidine biosynthesis Tb927.5.3810 Orotidine-5-phosphate decarboxylase/orota...te phosphoribosyltransferase, putative 999953 Trypanosoma brucei brucei (strain 927/4 GUTat10.1) 3657490 Q57U85 ...

  13. Protein: MPA5 [TP Atlas

    Lifescience Database Archive (English)

    Full Text Available MPA5 Pyrimidine biosynthesis Tc00.1047053507059.60 Orotidine-5-phosphate decarboxyl...ase/orotate phosphoribosyltransferase, putative 353153 Trypanosoma cruzi (strain CL Brener) 3542677 Q4DBC5 ...

  14. Department of Che

    African Journals Online (AJOL)

    USER

    2015-03-26

    Mar 26, 2015 ... The average concentrations of zinc, iron, copper and chromium were 0.153 mg ... Hardness, TS, TDS, SS, Alkalinity, acidity, DO, BOD5, phosphate, chloride and sulphate concentrations ... textiles are produced. These explain ...

  15. Allosteric regulation and communication between subunits in uracil phosphoribosyltransferase from Sulfolobus solfataricus

    DEFF Research Database (Denmark)

    Arent, Susan; Harris, Pernille; Jensen, Kaj Frank

    2005-01-01

    Uracil phosphoribosyltransferase (UPRTase) catalyzes the conversion of 5-phosphate-alpha-1-diphosphate (PRPP) and uracil to uridine 5'-monophosphate (UMP) and diphosphate. The UPRTase from Sulfolobus solfataricus has a unique regulation by nucleoside triphosphates compared to UPRTases from other...

  16. Synthesis of 2'(3')-O-DL-alanyl hexainosinic acid using T4 RNA ligase: suppression of the enzymic reverse transfer reaction by alkaline phosphatase.

    Science.gov (United States)

    Profy, A T; Lo, K M; Usher, D A

    1983-03-11

    2'(3')-O-DL-Alanyl (Ip)5I was synthesized by a new method. An alanine ortho ester of inosine 5'-phosphate was added to (Ip)4I using the ATP-independent reaction of T4 RNA ligase, and the product was converted smoothly to the desired ester. The enzymic reverse transfer reaction was conveniently suppressed by the dephosphorylation of the adenosine 5'-phosphate coproduct, catalyzed in situ by alkaline phosphatase.

  17. Pyridoxal phosphate-dependent neonatal epileptic encephalopathy.

    Science.gov (United States)

    Bagci, S; Zschocke, J; Hoffmann, G F; Bast, T; Klepper, J; Müller, A; Heep, A; Bartmann, P; Franz, A R

    2008-03-01

    Pyridox(am)ine-5'-phosphate oxidase converts pyridoxine phosphate and pyridoxamine phosphate to pyridoxal phosphate, a cofactor in many metabolic reactions, including neurotransmitter synthesis. A family with a mutation in the pyridox(am)ine-5'-phosphate oxidase gene presenting with neonatal seizures unresponsive to pyridoxine and anticonvulsant treatment but responsive to pyridoxal phosphate is described. Pyridoxal phosphate should be considered in neonatal epileptic encephalopathy unresponsive to pyridoxine.

  18. Typical and atypical phenotypes of PNPO deficiency with elevated CSF and plasma pyridoxamine on treatment.

    Science.gov (United States)

    Ware, Tyson L; Earl, John; Salomons, Gajja S; Struys, Eduard A; Peters, Heidi L; Howell, Katherine B; Pitt, James J; Freeman, Jeremy L

    2014-05-01

    Pyridox(am)ine phosphate oxidase (PNPO) deficiency causes severe early infantile epileptic encephalopathy and has been characterized as responding to pyridoxal-5'-phosphate but not to pyridoxine. Two males with PNPO deficiency and novel PNPO mutations are reported and their clinical, metabolic, and video-electroencephalographic (EEG) findings described. The first child showed electro-clinical responses to pyridoxine and deterioration when pyridoxine was withheld. At last review, he has well-controlled epilepsy with pyridoxal-5'-phosphate monotherapy and an autism spectrum disorder. The second child had a perinatal middle cerebral artery infarct and a myoclonic encephalopathy. He failed to respond to pyridoxine but responded well to pyridoxal-5'-phosphate. At the age of 21 months he has global developmental delay and hemiparesis but is seizure-free with pyridoxal-5'-phosphate monotherapy. Plasma and cerebrospinal fluid pyridoxamine levels were increased in both children during treatment with pyridoxine or pyridoxal-5'-phosphate. These observations indicate that differential responses to pyridoxine and pyridoxal-5'-phosphate treatment cannot be relied upon to diagnose PNPO deficiency.

  19. Diagnostic accuracy of motor evoked potentials to detect neurological deficit during idiopathic scoliosis correction: a systematic review.

    Science.gov (United States)

    Thirumala, Parthasarathy D; Crammond, Donald J; Loke, Yoon K; Cheng, Hannah L; Huang, Jessie; Balzer, Jeffrey R

    2017-03-01

    OBJECTIVE The goal of this study was to evaluate the efficacy of intraoperative transcranial motor evoked potential (TcMEP) monitoring in predicting an impending neurological deficit during corrective spinal surgery for patients with idiopathic scoliosis (IS). METHODS The authors searched the PubMed and Web of Science database for relevant lists of retrieved reports and/or experiments published from January 1950 through October 2014 for studies on TcMEP monitoring use during IS surgery. The primary analysis of this review fit the operating characteristic into a hierarchical summary receiver operating characteristic curve model to determine the efficacy of intraoperative TcMEP-predicted change. RESULTS Twelve studies, with a total of 2102 patients with IS were included. Analysis found an observed incidence of neurological deficits of 1.38% (29/2102) in the sample population. Of the patients who sustained a neurological deficit, 82.8% (24/29) also had irreversible TcMEP change, whereas 17.2% (5/29) did not. The pooled analysis using the bivariate model showed TcMEP change with sensitivity (mean 91% [95% CI 34%-100%]) and specificity (mean 96% [95% CI 92-98%]). The diagnostic odds ratio indicated that it is 250 times more likely to observe significant TcMEP changes in patients who experience a new-onset motor deficit immediately after IS correction surgery (95% CI 11-5767). TcMEP monitoring showed high discriminant ability with an area under the curve of 0.98. CONCLUSIONS A patient with a new neurological deficit resulting from IS surgery was 250 times more likely to have changes in TcMEPs than a patient without new deficit. The authors' findings from 2102 operations in patients with IS show that TcMEP monitoring is a highly sensitive and specific test for detecting new spinal cord injuries in patients undergoing corrective spinal surgery for IS. They could not assess the value of TcMEP monitoring as a therapeutic adjunct owing to the limited data available and their

  20. Simultaneous Determination of Underivatized Vitamin B1 and B6 in Whole Blood by Reversed Phase Ultra High Performance Liquid Chromatography Tandem Mass Spectrometry.

    Directory of Open Access Journals (Sweden)

    Johan Puts

    Full Text Available Vitamin B1 (thiamine-diphosphate and B6 (pyridoxal-5'phosphate are micronutrients. Analysis of these micronutrients is important to diagnose potential deficiency which often occurs in elderly people due to malnutrition, in severe alcoholism and in gastrointestinal compromise due to bypass surgery or disease. Existing High Performance Liquid Chromatography (HPLC based methods include the need for derivatization and long analysis time. We developed an Ultra High Performance Liquid Chromatography Tandem Mass spectrometry (UHPLC-MS/MS assay with internal standards for simultaneous measurement of underivatized thiamine-diphosphate and pyridoxal-5'phosphate without use of ion pairing reagent.Whole blood, deproteinized with perchloric acid, containing deuterium labelled internal standards thiamine-diphosphate(thiazole-methyl-D3 and pyridoxal-5'phosphate(methyl-D3, was analyzed by UHPLC-MS/MS. The method was validated for imprecision, linearity, recovery and limit of quantification. Alternate (quantitative method comparisons of the new versus currently used routine HPLC methods were established with Deming regression.Thiamine-diphosphate and pyridoxal-5'phosphate were measured within 2.5 minutes instrumental run time. Limits of detection were 2.8 nmol/L and 7.8 nmol/L for thiamine-diphosphate and pyridoxal-5'phosphate respectively. Limit of quantification was 9.4 nmol/L for thiamine-diphosphate and 25.9 nmol/L for pyridoxal-5'phosphate. The total imprecision ranged from 3.5-7.7% for thiamine-diphosphate (44-157 nmol/L and 6.0-10.4% for pyridoxal-5'phosphate (30-130 nmol/L. Extraction recoveries were 101-102% ± 2.5% (thiamine-diphosphate and 98-100% ± 5% (pyridoxal-5'phosphate. Deming regression yielded slopes of 0.926 and 0.990 in patient samples (n = 282 and national proficiency testing samples (n = 12 respectively, intercepts of +3.5 and +3 for thiamine-diphosphate (n = 282 and n = 12 and slopes of 1.04 and 0.84, intercepts of -2.9 and +20 for

  1. Comparison of Motor Inhibition in Variants of the Instructed-Delay Choice Reaction Time Task.

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    Quoilin, Caroline; Lambert, Julien; Jacob, Benvenuto; Klein, Pierre-Alexandre; Duque, Julie

    2016-01-01

    Using instructed-delay choice reaction time (RT) paradigms, many previous studies have shown that the motor system is transiently inhibited during response preparation: motor-evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS) over the primary motor cortex are typically suppressed during the delay period. This effect has been observed in both selected and non-selected effectors, although MEP changes in selected effectors have been more inconsistent across task versions. Here, we compared changes in MEP amplitudes in three different variants of an instructed-delay choice RT task. All variants required participants to choose between left and right index finger movements but the responses were either provided "in the air" (Variant 1), on a regular keyboard (Variant 2), or on a response device designed to control from premature responses (Variant 3). The task variants also differed according to the visual layout (more concrete in Variant 3) and depending on whether participants received a feedback of their performance (absent in Variant 1). Behavior was globally comparable between the three variants of the task although the propensity to respond prematurely was highest in Variant 2 and lowest in Variant 3. MEPs elicited in a non-selected hand were similarly suppressed in the three variants of the task. However, significant differences emerged when considering MEPs elicited in the selected hand: these MEPs were suppressed in Variants 1 and 3 whereas they were often facilitated in Variant 2, especially in the right dominant hand. In conclusion, MEPs elicited in selected muscles seem to be more sensitive to small variations to the task design than those recorded in non-selected effectors, probably because they reflect a complex combination of inhibitory and facilitatory influences on the motor output system. Finally, the use of a standard keyboard seems to be particularly inappropriate because it encourages participants to respond promptly with no

  2. Age and gender effects on submental motor-evoked potentials.

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    Sella, Oshrat; Jones, Richard D; Huckabee, Maggie-Lee

    2014-01-01

    It is not known whether there are age- and/or gender-related differences in magnitude of motor-evoked potentials (MEPs) of the submental muscles. Knowledge of this is important in investigations of neurophysiological aspects of swallowing. Forty healthy participants (20 males, 20 females; 20 young [21-35 years], 20 old [53-88 years]) were recruited. Surface electromyography (EMG) electrodes were placed at midline underlying the submental muscle group. Age- and gender-related differences were evaluated in two neurophysiologic measures of swallowing: MEPs stimulated by single-pulse transcranial magnetic stimulation (TMS) over the motor cortex and surface electromyography (sEMG) recorded from the same submental muscle group during non-stimulated swallows. The older participants had larger MEPs during saliva swallowing than the young participants (p = 0.04, d = 0.86). Conversely, the older participants had lower amplitude submental EMG activity during non-stimulated swallows (p = 0.045, d = 0.67). Gender had no significant effect on MEP magnitude and on submental activity during saliva swallowing. There were no effects of age or gender on MEP latencies. These findings suggest deterioration in muscle function with age in a sample of healthy adults presenting with functional swallowing. We speculate that muscular decline is partially ameliorated by increased cortical activity-i.e., increased submental MEPs-so as to preserve swallowing function in healthy older subjects. These findings emphasize the need for different reference points for evaluation of submental MEPs of different age groups.

  3. A microcalorimetric study of molecular interactions between immunoglobulin G and hydrophobic charge-induction ligand.

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    Yuan, Xiao-Ming; Lin, Dong-Qiang; Zhang, Qi-Lei; Gao, Dong; Yao, Shan-Jing

    2016-04-22

    Hydrophobic charge-induction chromatography (HCIC) with 4-mercaptoethyl-pyridine (MEP) as the ligand is a novel technology for antibody purification. In this study, isothermal titration calorimetry (ITC) was used to evaluate the molecular interactions between MEP ligand and immunoglobulin G (IgG). Three types of IgG molecules including human IgG (hIgG), bovine IgG (bIgG) and a monoclonal antibody (mAb) were investigated with human serum albumins (HSA) and bovine serum albumin (BSA) as the comparison. The thermodynamic parameters obtained from ITC were compared with the adsorption data. The results indicated that MEP binding to protein at neutral pH was entropy driven and induced by multimodal molecular interactions that was dominated by hydrophobic forces. The interactions between MEP and IgGs were stronger than that of albumins, which resulted in high binding affinity of IgGs. Moreover, the effects of pH and salt addition on MEP-hIgG binding were studied. The change of enthalpy increased obviously with the decrease of pH, which revealed that the electrostatic forces dominated the MEP-hIgG interactions at acidic condition and caused typical charge-induced elution of HCIC. Salt addition influenced both hydrophobic and electrostatic interactions. With the increase of salt concentration, the hydrophobic interactions decreased first and then increased, while the electrostatic interactions showed the opposite trend. This resulted in trade-off between the multimodal interactions, which caused the salt-tolerant property of MEP resin. In general, ITC studies revealed the molecular mechanism of three critical characteristics of HCIC, multimodal interactions, pH-dependent and salt-tolerant properties.

  4. Augmentation of motor evoked potentials using multi-train transcranial electrical stimulation in intraoperative neurophysiologic monitoring during spinal surgery.

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    Tsutsui, Shunji; Iwasaki, Hiroshi; Yamada, Hiroshi; Hashizume, Hiroshi; Minamide, Akihito; Nakagawa, Yukihiro; Nishi, Hideto; Yoshida, Munehito

    2015-02-01

    Transcranial motor evoked potentials (TcMEPs) are widely used to monitor motor function during spinal surgery. Improvements in transcranial stimulation techniques and general anesthesia have made it possible to record reliable and reproducible potentials. However, TcMEPs are much smaller in amplitude compared with compound muscle action potentials (CMAPs) evoked by maximal peripheral nerve stimulation. In this study, multi-train transcranial electrical stimulation (mt-TES) was introduced to enhance TcMEPs, and the optimal setting of mt-TES was investigated. In 30 patients undergoing surgical correction of spinal deformities (4 males and 26 females with normal motor status; age range 11-75 years), TcMEPs from the abductor hallucis (AH) and quadriceps femoris (QF) were analyzed. A multipulse (train) stimulus with an individual pulse width of 0.5 ms and an inter-pulse interval of 2 ms was delivered repeatedly (2-7 times) at different rates (2, 5, and 10 Hz). TcMEP amplitudes increased with the number of train stimuli for AH, with the strongest facilitation observed at 5 Hz. The response amplitude increased 6.1 times on average compared with single-train transcranial electrical stimulation (st-TES). This trend was also observed in the QF. No adverse events (e.g., seizures, cardiac arrhythmias, scalp burns, accidental injury resulting from patient movement) were observed in any patients. Although several facilitative techniques using central or peripheral stimuli, preceding transcranial electrical stimulation, have been recently employed to augment TcMEPs during surgery, responses are still much smaller than CMAPs. Changing from conventional st-TES to mt-TES has potential to greatly enhance TcMEP responses.

  5. Design,Synthesis and Biological Activity of Ethyl 2-(N-Substituted-arylsulfonamido)-2-oxoacetate

    Institute of Scientific and Technical Information of China (English)

    WANG Bao-lei; WU Jing; HE Feng-qi; LI Yon-ghong; LI Zheng-ming

    2008-01-01

    Thirteen new ethyl 2-(N-substituted-arylsulfonamido)-2-oxoacetates(3a-3m),based on the structure of Ketol-acid reductoisomerase(KARI) inhibitor IpOHA,were designed and synthesized,Their structures were established on the basis of 1H NMR,IR,MS,and elemental analyses,The bioassay result reveals that the structural changes from hydroxyl group on the N atom of IpOHA to arylsulfonyl groups does not enhance the inhibitory activity of the compounds to KARI in vitro,Compounds 3c,3h,3k,and 3m are more effective than IpOHA against the monocotyledonous barnygrass at 100 μg/mL in herbicidal tests.

  6. Production of 2-butanol from crude glycerol by a genetically-engineered Klebsiella pneumoniae strain.

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    Oh, Baek-Rock; Heo, Sun-Yeon; Lee, Sung-Mok; Hong, Won-Kyung; Park, Jang Min; Jung, You Ree; Kim, Dae-Hyuk; Sohn, Jung-Hoon; Seo, Jeong-Woo; Kim, Chul Ho

    2014-01-01

    Klebsiella pneumoniae was engineered to produce 2-butanol from crude glycerol as a sole carbon source by expressing acetolactate synthase (ilvIH), keto-acid reducto-isomerase (ilvC) and dihydroxy-acid dehydratase (ilvD) from K. pneumoniae, and α-ketoisovalerate decarboxylase (kivd) and alcohol dehydrogenase (adhA) from Lactococcus lactis. Engineered K. pneumonia, ∆ldhA/pBR-iBO (ilvIH–ilvC–ilvD–kivd–adhA), produced 2-butanol (160 mg l−1) from crude glycerol. To increase the yield of 2-butanol, we eliminated the 2,3-butanediol pathway from the recombinant strain by inactivating α-acetolactate decarboxylase (adc). This further engineering step improved the yield of 2-butanol from 160 to 320 mg l−1. This represents the first successful attempt to produce 2-butanol from crude glycerol.

  7. 低频电刺激对健康成年人体感和运动诱发电位的影响%Effects of Low-frequency Electrical Stimulation on Sense and Motor Evoked Potentials of Healthy Adult Human

    Institute of Scientific and Technical Information of China (English)

    向云; 尉洋

    2013-01-01

    Objective: to observe the effects of low-frequency electrical stimulation (LES) on healthy adult with somatosensory evoked potential (SEP) and motor evoked potential (MEP). Method: 25 healthy adults (thirteen males and twelve females, with a mean age of 42.9 and a standard deviation of 5.7) participated in the study. SEP and MEP were measured before and after the LES stimulation. Results: After LES, the latency of SEP and MEP for the stimulated side became shorter and the amplitude became greater. These changes in latency and amplitude were statistically significant (P<0.05). For the unstimulated side, the changes of SEP and MEP did not show statistically significant difference. Conclusion: The SEP and MEP parameters, especially the amplitude, can be used to evaluate the effect of LES on central nervous system (CNS).%  目的:观察低频电刺激(Low-frequency Electrical Stimulation,LES)对健康成年人体感诱发电位(Somatosensory Evoked Potential,SEP)及运动诱发电位(Motor Evoked Potential,MEP)的影响。方法:入选25例健康成年人(男13例,女12例,平均年龄42.9±5.7岁),采用经颅磁刺激仪(TMS)及肌电图仪,分别测量 LES 刺激前后 SEP 值及 MEP 值。结果:健康成年人 LES 刺激后 SEP 及 MEP 值的潜伏期缩短、波幅增高,与刺激前比较,差异有统计学意义(P<0.05);非刺激侧无明显变化。结论:健康成年人 LES 刺激前后 SEP 及 MEP 参数值均有显著性变化,尤以波幅明显,提示电刺激对中枢神经系统存在作用。

  8. Dosimetric impact of mixed-energy volumetric modulated arc therapy plans for high-risk prostate cancer

    Directory of Open Access Journals (Sweden)

    Shyam Pokharel

    2013-10-01

    Full Text Available Purpose: This study investigated the dosimetric impact of mixing low and high energy treatment plans for prostate cancer treated with volumetric modulated arc therapy (VMAT technique in the form of RapidArc.Methods: A cohort of 12 prostate cases involving proximal seminal vesicles and lymph nodes was selected for this retrospective study. For each prostate case, the single-energy plans (SEPs and mixed-energy plans (MEPs were generated.  First, the SEPs were created using 6 mega-voltage (MV energy for both the primary and boost plans. Second, the MEPs were created using 16 MV energy for the primary plan and 6 MV energy for the boost plan. The primary and boost MEPs used identical beam parameters and same dose optimization values as in the primary and boost SEPs for the corresponding case. The dosimetric parameters from the composite plans (SEPs and MEPs were evaluated. Results: The dose to the target volume was slightly higher (on average <1% in the SEPs than in the MEPs. The conformity index (CI and homogeneity index (HI values between the SEPs and MEPs were comparable. The dose to rectum and bladder was always higher in the SEPs (average difference up to 3.7% for the rectum and up to 8.4% for the bladder than in the MEPs. The mean dose to femoral heads was higher by about 0.8% (on average in the MEPs than in the SEPs. The number of monitor units and integral dose were higher in the SEPs compared to the MEPs by average differences of 9.1% and 5.5%, respectively.Conclusion: The preliminary results from this study suggest that use of mixed-energy VMAT plan for high-risk prostate cancer could potentially reduce the integral dose and minimize the dose to rectum and bladder, but for the higher femoral head dose.-----------------------------------------------Cite this article as:Pokharel S. Dosimetric impact of mixed-energy volumetric modulated arc therapy plans for high-risk prostate cancer. Int J Cancer Ther Oncol 2013;1(1:01011.DOI: http

  9. Genomewide association study of methane emissions in Angus beef cattle with validation in dairy cattle.

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    Manzanilla-Pech, C I V; De Haas, Y; Hayes, B J; Veerkamp, R F; Khansefid, M; Donoghue, K A; Arthur, P F; Pryce, J E

    2016-10-01

    Methane (CH) is a product of enteric fermentation in ruminants, and it represents around 17% of global CH emissions. There has been substantial effort from the livestock scientific community toward tools that can help reduce this percentage. One approach is to select for lower emitting animals. To achieve this, accurate genetic parameters and identification of the genomic basis of CH traits are required. Therefore, the objectives of this study were 1) to perform a genomewide association study to identify SNP associated with several CH traits in Angus beef cattle (1,020 animals) and validate them in a lactating Holstein population (population 1 [POP1]; 205 animals); 2) to validate significant SNP for DMI and weight at test (WT) from a second Holstein population, from a previous study (population 2 [POP2]; 903 animals), in an Angus population; and 3) to evaluate 2 different residual CH traits and determine if the genes associated with CH also control residual CH traits. Phenotypes calculated for the genotyped Angus population included CH production (MeP), CH yield (MeY), CH intensity (MI), DMI, and WT. The Holstein population (POP1) was multiparous, with phenotypes on CH traits (MeP, MeY, and MI) plus genotypes. Additionally, 2 CH traits, residual genetic CH (RGM) and residual phenotypic CH (RPM), were calculated by adjusting MeP for DMI and WT. Estimated heritabilities in the Angus population were 0.30, 0.19, and 0.15 for MeP, RGM, and RPM, respectively, and genetic correlations of MeP with DMI and WT were 0.83 and 0.80, respectively. Estimated heritabilities in Holstein POP1 were 0.23, 0.30, and 0.42 for MeP, MeY, and MI, respectively. Strong associations with MeP were found on chromosomes 4, 12, 14, 20, and 30 at Angus population, the number of significant SNP for MeP at Angus population was used to estimate genetic parameters for MeP and MeY in Holstein POP1, the genetic variance and, consequently, the heritability slightly increased, meaning that most of the

  10. Development of a brief multidisciplinary education programme for patients with osteoarthritis

    Directory of Open Access Journals (Sweden)

    Moe Rikke H

    2011-11-01

    Full Text Available Abstract Background Osteoarthritis (OA is a prevalent progressive musculoskeletal disorder, leading to pain and disability. Patient information and education are considered core elements in treatment guidelines for OA; however, there is to our knowledge no evidence-based recommendation on the best approach, content or length on educational programmes in OA. Objective: to develop a brief, patient oriented disease specific multidisciplinary education programme (MEP to enhance self-management in patients with OA. Method Twelve persons (80% female mean age 59 years diagnosed with hand, hip or knee OA participated in focus group interviews. In the first focus group, six participants were interviewed about their educational needs, attitudes and expectations for the MEP. The interviews were transcribed verbatim and thereafter condensed. Based on results from focus group interviews, current research evidence, clinical knowledge and patients' experience, a multidisciplinary OA team (dietist, nurse, occupational therapist, pharmacist, physical therapist and rheumatologist and a patient representative developed a pilot-MEP after having attended a work-shop in health pedagogics. Finally, the pilot-MEP was evaluated by a second focus group consisting of four members from the first focus group and six other experienced patients, before final adjustments were made. Results The focus group interviews revealed four important themes: what is OA, treatment options, barriers and coping strategies in performing daily activities, and how to live with osteoarthritis. Identified gaps between patient expectations and experience with the pilot-programme were discussed and adapted into a final MEP. The final MEP was developed as a 3.5 hour educational programme provided in groups of 6-9 patients. All members from the multidisciplinary team are involved in the education programme, including a facilitator who during the provision of the programme ensures that the individual

  11. A comparison of the effects of desflurane versus propofol on transcranial motor-evoked potentials in pediatric patients.

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    Holdefer, Robert N; Anderson, Corrie; Furman, Michele; Sangare, Yoro; Slimp, Jefferson C

    2014-12-01

    The aim was to compare the effects of propofol and desflurane anesthesia on transcranial motor evoked potentials (MEPs) from pediatric patients undergoing surgery for spinal deformities. Desflurane and propofol cohorts (25 patients each) were obtained retrospectively and matched for patient characteristics and surgical approach. MEPs from the thenar eminence and abductor hallucis were compared during maintenance anesthesia on desflurane (0.6-0.8 MAC) or propofol infusion (150-300 μg/kg/min). MEP amplitudes and durations were obtained for successive 30-min intervals for 150 min, beginning 60 min after maintenance anesthesia. Mean peak to peak amplitudes of MEPs under desflurane anesthesia from the thenar eminence (419 μV) and abductor hallucis (386 μv) were not significantly different from those under propofol (608 μV, 343 μV, thenar, and abductor hallucis, respectively). Stimulation was greater by 42 V and 136 mA, and trains were slightly longer in the desflurane compared to the propofol group (p propofol cohorts remained the same or increased (71 % of cases) when those after 150 min were compared to those in the first 30-min interval. MEPs with good amplitudes were obtained under desflurane only anesthesia that were comparable to propofol only anesthesia in pediatric patients during surgery for spinal deformities. There was no evidence for anesthetic fade over the time period examined. When used by itself, desflurane can be considered a viable alternative to propofol anesthesia.

  12. Task-dependent differences in corticobulbar excitability of the submental motor projections: Implications for neural control of swallowing.

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    Doeltgen, Sebastian H; Ridding, Michael C; Dalrymple-Alford, John; Huckabee, Maggie-Lee

    2011-01-15

    It has been suggested that the primary motor cortex plays a substantial role in the neural circuitry that controls swallowing. Although its role in the voluntary oral phase of swallowing is undisputed, its precise role in motor control of the more reflexive, pharyngeal phase of swallowing is unclear. The contribution of the primary motor cortex to the pharyngeal phase of swallowing was examined using transcranial magnetic stimulation (TMS) to evoke motor evoked potentials (MEPs) in the anterior hyomandibular muscle group during either volitional submental muscle contraction or contraction during the pharyngeal phase of both volitionally, and reflexively, initiated swallowing. For each subject, in all three conditions, TMS was triggered when submental surface EMG (sEMG) reached 75% of the mean maximal submental sEMG amplitude measured during 10 volitional swallows. MEPs recorded during volitional submental muscle contraction were elicited in 22 of the 35 healthy subjects examined (63%). Only 16 of these 22 subjects (45.7%) also displayed MEPs recorded during volitional swallowing, but their MEP amplitudes were larger when triggered by submental muscle contraction than when triggered by volitional swallowing. Additionally, only 7 subjects (of 19 tested) showed MEPs triggered by submental muscle contraction during a reflexively triggered pharyngeal swallow. These differences indicate differing levels of net M1 excitability during execution of the investigated tasks, possibly brought about by task-dependent changes in the balance of excitatory and inhibitory neural activity. Copyright © 2010 Elsevier Inc. All rights reserved.

  13. Can the hydrophilicity of functional monomers affect chemical interaction?

    Science.gov (United States)

    Feitosa, V P; Ogliari, F A; Van Meerbeek, B; Watson, T F; Yoshihara, K; Ogliari, A O; Sinhoreti, M A; Correr, A B; Cama, G; Sauro, S

    2014-02-01

    The number of carbon atoms and/or ester/polyether groups in spacer chains may influence the interaction of functional monomers with calcium and dentin. The present study assessed the chemical interaction and bond strength of 5 standard-synthesized phosphoric-acid ester functional monomers with different spacer chain characteristics, by atomic absorption spectroscopy (AAS), ATR-FTIR, thin-film x-ray diffraction (TF-XRD), scanning electron microscopy (SEM), and microtensile bond strength (μTBS). The tested functional monomers were 2-MEP (two-carbon spacer chain), 10-MDP (10-carbon), 12-MDDP (12-carbon), MTEP (more hydrophilic polyether spacer chain), and CAP-P (intermediate hydrophilicity ester spacer). The intensity of monomer-calcium salt formation measured by AAS differed in the order of 12-MDDP=10-MDP>CAP-P>MTEP>2-MEP. FTIR and SEM analyses of monomer-treated dentin surfaces showed resistance to rinsing for all monomer-dentin bonds, except with 2-MEP. TF-XRD confirmed the weaker interaction of 2-MEP. Highest µTBS was observed for 12-MDDP and 10-MDP. A shorter spacer chain (2-MEP) of phosphate functional monomers induced formation of unstable monomer-calcium salts, and lower chemical interaction and dentin bond strength. The presence of ester or ether groups within longer spacer carbon chains (CAP-P and MTEP) may affect the hydrophilicity, μTBS, and also the formation of monomer-calcium salts.

  14. HIGHLIGHTS OF MAGNETOELECTROPOLISHING

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    Tadeusz eHryniewicz

    2014-05-01

    Full Text Available The research work has been concerned on the studies and development of electrochemical polishing in the magnetic field (MEP in comparison with the standard electropolishing methods performed without stirring (EP and the process with the forced electrolyte mixing (MIX. Advanced techniques were used in the studies, to measure the effects of the surface treatment. They are as follows: scanning electron microscopy (SEM/EDS, X-ray Photoelectron Spectroscopy (XPS, Secondary Ion Mass Spectroscopy (SIMS, surface roughness, and nanoindentation measurements. For the corrosion studies, the electrochemical methods were used, such as: open circuit potential OCP, potentiodynamic curves PC, and electrochemical impedance spectroscopy EIS measurements. The MEP process is advised mainly due to the opportunity to enrich the surface layer with the chromium compounds (austenitic stainless steels, or titanium compounds (CP Ti Grade 2, Nitinol. The surface layers of biomaterials after MEP process contain much lower amount of carcinogenic compounds, like chromium VI oxidation stage (Cr6+ (austenitic stainless steels and nickel compounds (austenitic stainless steel & Nitinol versus those ones obtained after EP & MIX treatments. It is interesting that apart from the significant modification of the surface layer obtained after MEP, also mechanical properties, such as nanohardness, modulus of elasticity, and mechanical resistance to bending and torsion, undergo considerable advantageous changes. All they make the MEP process very promising for application in many clean industries, such as medical equipment and devices, electronics, food industry, etc.

  15. Determination of parabens in urine samples by microextraction using packed sorbent and ultra-performance liquid chromatography coupled to tandem mass spectrometry.

    Science.gov (United States)

    Cristina Jardim, Valeria; de Paula Melo, Lidervan; Soares Domingues, Diego; Costa Queiroz, Maria Eugênia

    2015-01-01

    A simple, sensitive, and selective method using ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) was developed and validated for simultaneous determination of parabens [methyl paraben (MeP), ethyl paraben (EtP), propyl paraben (PrP), butyl paraben (BuP), and benzyl paraben (BzP)] in human urine samples. After microextraction by packed sorbent (MEPS) using a C18 phase, the parabens were separated on a Kinetex C18 column (100 mm × 2.1 mm × 1.7 μm) within 4.6 min using isocratic elution. These compounds were detected on a triple quadrupole tandem mass spectrometer using the multiple reactions monitoring (MRM) mode via an electrospray ionization source operating in the negative ionization mode. Important factors that influence MEPS performance were evaluated, such as the sample pH, draw-eject sample volume, clean-up step, and desorption conditions. The proposed MEPS/UPLC-MS/MS method presented a linear range from 0.5 ng mL(-1) (limit of quantification - LOQ) to 50 ng mL(-1), and interassay precision with coefficients of variation lower than 15%, and relative standard error values of the accuracy ranged from -8.8% to 15%. The MEPS/UPLC-MS/MS method was applied successfully to determine parabens in urine samples from 30 postpartum volunteers, enabling assessment of human exposure to these compounds. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Differential activation of ammonium transporters during the accumulation of ammonia by Colletotrichum gloeosporioides and its effect on appressoria formation and pathogenicity.

    Science.gov (United States)

    Shnaiderman, Chen; Miyara, Itay; Kobiler, Ilana; Sherman, Amir; Prusky, Dov

    2013-03-01

    Ammonium secreted by the post-harvest pathogen Colletotrichum gloeosporioides during host colonization accumulates in the host environment due to enhanced fungal nitrogen metabolism. Two types of ammonium transporter-encoding genes, AMET and MEP, are expressed during pathogenicity. Gene disruption of AMET, a gene modulating ammonia secretion, showed twofold reduced ammonia secretion and 45% less colonization on avocado fruit, suggesting a contribution to pathogenicity. MEPB, a gene modulating ammonium transport, is expressed by C. gloeosporioides during pathogenicity and starvation conditions in culture. Gene disruption of MEPB, the most highly expressed gene of the MEP family, resulted in twofold overexpression of MEPA and MEPC but reduced colonization, suggesting MEPB expression's contribution to pathogenicity. Analysis of internal and external ammonia accumulation by ΔmepB strains in mycelia and germinated spores showed rapid uptake and accumulation, and reduced secretion of ammonia in the mutant versus wild-type (WT) strains. Ammonia uptake by the WT germinating spores but not by the ΔmepB strain with compromised ammonium transport activated cAMP and transcription of PKA subunits PKAR and PKA2. ΔmepB mutants showed 75% less appressorium formation and colonization than the WT, which was partially restored by 10 mM exogenous ammonia. Thus, whereas both AMET and MEPB genes modulate ammonia secretion, only MEPB contributes to ammonia accumulation by mycelia and germinating spores that activate the cAMP pathways, inducing the morphogenetic processes contributing to C. gloeosporioides pathogenicity.

  17. Development of an analytical method coupling cell membrane chromatography with gas chromatography-mass spectrometry via microextraction by packed sorbent and its application in the screening of volatile active compounds in natural products.

    Science.gov (United States)

    Li, Miao; Wang, Sicen; He, Langchong

    2015-01-01

    Natural products (NPs) are important sources of lead compounds in modern drug discovery. To facilitate the screening of volatile active compounds in NPs, we have developed a new biochromatography method that uses rat vascular smooth muscle cells (VSMC), which are rich in L-type calcium channels (LCC), to prepare the stationary phase. This integrated method, which couples cell membrane chromatography (CMC) with gas chromatography-mass spectrometry (GC-MS) via microextraction by packed sorbent (MEPS) technology, has been termed VSMC/CMC-MEPS-GC-MS. Methodological validation confirmed its specificity, reliability and convenience. Screening results for Radix Angelicae Dahuricae and Fructus Cnidii obtained using VSMC/CMC-MEPS-GC-MS were consistent with those obtained using VSMC/CMC-offline-GC-MS. MEPS connection plays as simplified solid-phase extraction and replaces the uncontrollable evaporation operation in reported offline connections, so our new method is supposed to be more efficient and reliable than the offline ones, especially for compounds that are volatile, thermally unstable or difficult to purify. In application, senkyunolide A and ligustilide were preliminary identified as the volatile active components in Rhizoma Chuanxiong. We have thus confirmed the suitability of VSMC/CMC-MEPS-GC-MS for volatile active compounds screening in NP. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Soil Moisture and Vegetation Controls on Surface Energy Balance Using the Maximum Entropy Production Model of Evapotranspiration

    Science.gov (United States)

    Wang, J.; Parolari, A.; Huang, S. Y.

    2014-12-01

    The objective of this study is to formulate and test plant water stress parameterizations for the recently proposed maximum entropy production (MEP) model of evapotranspiration (ET) over vegetated surfaces. . The MEP model of ET is a parsimonious alternative to existing land surface parameterizations of surface energy fluxes from net radiation, temperature, humidity, and a small number of parameters. The MEP model was previously tested for vegetated surfaces under well-watered and dry, dormant conditions, when the surface energy balance is relatively insensitive to plant physiological activity. Under water stressed conditions, however, the plant water stress response strongly affects the surface energy balance. This effect occurs through plant physiological adjustments that reduce ET to maintain leaf turgor pressure as soil moisture is depleted during drought. To improve MEP model of ET predictions under water stress conditions, the model was modified to incorporate this plant-mediated feedback between soil moisture and ET. We compare MEP model predictions to observations under a range of field conditions, including bare soil, grassland, and forest. The results indicate a water stress function that combines the soil water potential in the surface soil layer with the atmospheric humidity successfully reproduces observed ET decreases during drought. In addition to its utility as a modeling tool, the calibrated water stress functions also provide a means to infer ecosystem influence on the land surface state. Challenges associated with sampling model input data (i.e., net radiation, surface temperature, and surface humidity) are also discussed.

  19. Maternal meta-emotion philosophy and socialization of adolescent affect: The moderating role of adolescent temperament.

    Science.gov (United States)

    Yap, Marie B H; Allen, Nicholas B; Leve, Craig; Katz, Lynn Fainsilber

    2008-10-01

    This study explored the associations between maternal meta-emotion philosophy (MEP) and maternal socialization of preadolescents' positive and negative affect. It also investigated whether adolescent temperament and gender moderated this association. MEP involves parental awareness and acceptance of their own and their child's emotions and their coaching of child emotions. Event-planning (EPI) and problem-solving (PSI) interactions were observed in 163 mother-adolescent dyads, and maternal behaviors were coded to provide indices of socialization responses to adolescent emotion. In addition, maternal MEP was assessed via interview, and preadolescents provided self-reports of temperament on 2 occasions. Maternal MEP that is higher in awareness and acceptance was associated with reduced likelihood of negative socialization behaviors during the EPI. Moreover, preadolescents' temperamental negative emotionality (NEM) and effortful control (EC) moderated some of these MEP-socialization associations. During the positive EPI task, greater maternal awareness and acceptance is associated with reduced likelihood of negative socialization toward preadolescents with "easy" temperaments, that is, low NEM or high EC. However, during the conflict task, greater maternal awareness is associated with reduced likelihood of negative socialization among preadolescents with "difficult" temperaments. Some male-specific associations were also found. Copyright 2008 APA, all rights reserved.

  20. Eating tools in hand activate the brain systems for eating action: a transcranial magnetic stimulation study.

    Science.gov (United States)

    Yamaguchi, Kaori; Nakamura, Kimihiro; Oga, Tatsuhide; Nakajima, Yasoichi

    2014-07-01

    There is increasing neuroimaging evidence suggesting that visually presented tools automatically activate the human sensorimotor system coding learned motor actions relevant to the visual stimuli. Such crossmodal activation may reflect a general functional property of the human motor memory and thus can be operating in other, non-limb effector organs, such as the orofacial system involved in eating. In the present study, we predicted that somatosensory signals produced by eating tools in hand covertly activate the neuromuscular systems involved in eating action. In Experiments 1 and 2, we measured motor evoked response (MEP) of the masseter muscle in normal humans to examine the possible impact of tools in hand (chopsticks and scissors) on the neuromuscular systems during the observation of food stimuli. We found that eating tools (chopsticks) enhanced the masseter MEPs more greatly than other tools (scissors) during the visual recognition of food, although this covert change in motor excitability was not detectable at the behavioral level. In Experiment 3, we further observed that chopsticks overall increased MEPs more greatly than scissors and this tool-driven increase of MEPs was greater when participants viewed food stimuli than when they viewed non-food stimuli. A joint analysis of the three experiments confirmed a significant impact of eating tools on the masseter MEPs during food recognition. Taken together, these results suggest that eating tools in hand exert a category-specific impact on the neuromuscular system for eating.

  1. Different corticospinal control between discrete and rhythmic movement of the ankle

    Directory of Open Access Journals (Sweden)

    Yumeno eGoto

    2014-07-01

    Full Text Available We investigated differences in corticospinal and spinal control between discrete and rhythmic ankle movements. Motor evoked potentials (MEPs in the tibialis anterior and soleus muscles and soleus H-reflex were elicited in the middle of the plantar flexion phase during discrete ankle movement or in the initial or later cycles of rhythmic ankle movement. The H-reflex was evoked at an intensity eliciting a small M-wave and MEPs were elicited at an intensity of 1.2 times the motor threshold of the soleus MEPs. Only trials in which background EMG level, ankle angle, and ankle velocity were similar among the movement conditions were included for data analysis. In addition, only trials with a similar M-wave were included for data analysis in the experiment evoking H-reflexes. Results showed that H reflex and MEP amplitudes in the soleus muscle during discrete movement were not significantly different from those during rhythmic movement. MEP amplitude in the tibialis anterior muscle during the later cycles of rhythmic movement was significantly larger than that during the initial cycle of the rhythmic movement or during discrete movement. Higher corticospinal excitability in the tibialis anterior muscle during the later cycles of rhythmic movement may reflect changes in corticospinal control from the initial cycle to the later cycles of rhythmic movement.

  2. Phase- and Workload-Dependent Changes in Corticospinal Excitability to the Biceps and Triceps Brachii during Arm Cycling

    Directory of Open Access Journals (Sweden)

    Alyssa-Joy Spence

    2016-12-01

    Full Text Available This is the first study to examine corticospinal excitability (CSE to antagonistic muscle groups during arm cycling. Transcranial magnetic stimulation (TMS of the motor cortex and transmastoid electrical stimulation (TMES of the corticospinal tract were used to assess changes in supraspinal and spinal excitability, respectively. TMS induced motor evoked potentials (MEPs and TMES induced cervicomedullary evoked potentials (CMEPs were recorded from the biceps and triceps brachii at two positions, mid-elbow flexion and extension, while cycling at 5% and 15% of peak power output. While phase-dependent modulation of MEP and CMEP amplitudes occurred in the biceps brachii, there was no difference between flexion and extension for MEP amplitudes in the triceps brachii and CMEP amplitudes were higher during flexion than extension. Furthermore, MEP amplitudes in both biceps and triceps brachii increased with increased workload. CMEP amplitudes increased with higher workloads in the triceps brachii, but not biceps brachii, though the pattern of change in CMEPs was similar to MEPs. Differences between changes in CSE between the biceps and triceps brachii suggest that these antagonistic muscles may be under different neural control during arm cycling. Putative mechanisms are discussed.

  3. Different stimulation frequencies alter synchronous fluctuations in motor evoked potential amplitude of intrinsic hand muscles – a TMS study.

    Directory of Open Access Journals (Sweden)

    Martin Victor Sale

    2016-03-01

    Full Text Available The amplitude of motor-evoked potentials (MEPs elicited with transcranial magnetic stimulation (TMS varies from trial-to-trial. Synchronous oscillations in cortical neuronal excitability contribute to this variability, however it is not known how different frequencies of stimulation influence MEP variability, and whether these oscillations are rhythmic or aperiodic. We stimulated the motor cortex with TMS at different regular (i.e., rhythmic rates, and compared this with pseudo-random (aperiodic timing. In 18 subjects, TMS was applied at three regular frequencies (0.05 Hz, 0.2 Hz, 1 Hz and one aperiodic frequency (mean 0.2 Hz. MEPs (n = 50 were recorded from three intrinsic hand muscles of the left hand with different functional and anatomical relations. MEP amplitude correlation was highest for the functionally related muscle pair, less for the anatomically related muscle pair and least for the functionally- and anatomically-unrelated muscle pair. MEP correlations were greatest with 1 Hz, and least for stimulation at 0.05 Hz. Corticospinal neuron synchrony is higher with shorter TMS intervals. Further, corticospinal neuron synchrony is similar irrespective of whether the stimulation is periodic or aperiodic. These findings suggest TMS frequency is a crucial consideration for studies using TMS to probe correlated activity between muscle pairs.

  4. The Number of Pulses Needed to Measure Corticospinal Excitability by Navigated Transcranial Magnetic Stimulation: Eyes Open vs. Close Condition

    Science.gov (United States)

    Bashir, Shahid; Yoo, Woo-Kyoung; Kim, Hyoung Seop; Lim, Hyun Sun; Rotenberg, Alexander; Abu Jamea, Abdullah

    2017-01-01

    Objective: Motor evoked potentials (MEPs) obtained by transcranial magnetic stimulation (TMS) enable measures of the corticospinal excitability (CSE). However the reliability of TMS-derived CSE measures is suboptimal due to appreciable pulse-to-pulse MEP amplitude variability. We thus calculated how many TMS–derived MEPs will be needed to obtain a reliable CSE measure in awake adult subjects, in the eyes open (EO) and eyes closed (EC) conditions. Methods: Twenty healthy adults (70% male) received 40 consecutive navigated TMS pulses (120% resting motor threshold, RMT) in the EO or EC conditions on two separate days in randomized order. Results: For either the EO or EC condition, the probability that the 95% confidence interval (CI) derived from consecutive MEP amplitude measured included the true CSE, increased when the number of consecutive stimuli increased (EO: p = 0.05; EC: p = 0.001). No significant effect of RMT, Mini-Mental State Examination (MMSE) score, or gender on the CSE estimates was identified. At least 34 consecutive stimuli were required to obtain a most reliable CSE estimate in the EO condition and 31 in the EC condition. Conclusion: Our findings indicate that >30 consecutive MEPs may be necessary in order to obtain a CSE measure in healthy adults.

  5. Further insights into post-exercise effects on H-reflexes and motor evoked potentials of the flexor carpi radialis muscles.

    Science.gov (United States)

    Kato, Takashi; Takeda, Yusaku; Tsuji, Toshio; Kasai, Tatsuya

    2003-01-01

    The present study investigated the relative contribution of the cortical and spinal mechanisms for post-exercise excitability changes in human motoneurons. Seven healthy right-handed adults with no known neuromuscular disabilities performed an isometric voluntary wrist flexion at submaximum continuous exertion. After the subjects continued muscle contraction until volitional fatigue, the H-reflexes induced by an electric stimulation and motor evoked potentials (MEPs) induced by a transcranial magnetic stimulation (TMS) from a flexor carpi radialis (FCR) muscle were recorded 7 times every 20 s. The H-reflex was used to assess excitability changes at the spinal level, and the MEP was used to study excitability changes at the cortical level. Hreflexes showed a depression (30% of control value) soon after the cessation of wrist flexion and recovered with time thereafter. On the other hand, an early (short latency) MEP showed facilitation immediately after the cessation of wrist flexion (50% of control value) and thereafter decreased. A possible mechanism for the contradictory results of the 2 tests, in spite of focusing on the same motoneuron pool, might be the different test potential sizes between them. In addition, a late (long latency) MEP response appeared with increasing exercise. With regard to the occurrence of late MEP response, a central mechanism may be proposed to explain the origin-that is, neural pathways with a high threshold that do not participate under normal circumstances might respond to an emergency level of muscle exercise, probably reflecting central effects of fatigue.

  6. Verification and intercomparison of mesoscale ensemble prediction systems in the Beijing 2008 Olympics Research and Development Project

    Science.gov (United States)

    Kunii, Masaru; Saito, Kazuo; Seko, Hiromu; Hara, Masahiro; Hara, Tabito; Yamaguchi, Munehiko; Gong, Jiandong; Charron, Martin; Du, Jun; Wang, Yong; Chen, Dehui

    2011-05-01

    During the period around the Beijing 2008 Olympic Games, the Beijing 2008 Olympics Research and Development Project (B08RDP) was conducted as part of the World Weather Research Program short-range weather forecasting research project. Mesoscale ensemble prediction (MEP) experiments were carried out by six organizations in near-real time, in order to share their experiences in the development of MEP systems. The purpose of this study is to objectively verify these experiments and to clarify the problems associated with the current MEP systems through the same experiences. Verification was performed using the MEP outputs interpolated into a common verification domain with a horizontal resolution of 15 km. For all systems, the ensemble spreads grew as the forecast time increased, and the ensemble mean improved the forecast errors compared with individual control forecasts in the verification against the analysis fields. However, each system exhibited individual characteristics according to the MEP method. Some participants used physical perturbation methods. The significance of these methods was confirmed by the verification. However, the mean error (ME) of the ensemble forecast in some systems was worse than that of the individual control forecast. This result suggests that it is necessary to pay careful attention to physical perturbations.

  7. Comparison of electrostatic potential around proteins calculated from Amber and AM1 charges: application to mutants of prion protein

    Science.gov (United States)

    Zuegg, Johannes; Bliznyuk, Andrey A.; Gready, Jill E.

    On the basis of arguments of complementary fit of shape and charge polarity or hydrophobicity, molecular electrostatic potentials (MEPs) around proteins are commonly used to deduce likely sites for interaction with ligands or other proteins, including for variations such as mutations. But protein MEPs calculated classically from fixed force field descriptions, including those with implicit solvent models such as in Delphi, do not allow for repolarization of protein residues within the protein system; hence, their representations are likely to be variably inaccurate. Linear-scaling methods now allow calculation of MEPs quantum mechanically for systems as large as proteins, and can account for polarization explicitly. Here we compare MEPs derived from AM1 charge distributions calculated by Mopac2000 with those from the classical Amber force field. Our models are mutants of prion protein (PrP), a protein with an unusually high number of charged residues. The results demonstrate that static point charges, as used in most current force fields, cannot reproduce the MEP of macromolecules. Also, it is not sufficient to account for the influence of nearby atoms connected by chemical bonds; the influence of nearby atoms in space is at least as important. Thus, further progress in the accuracy and wider applicability of force fields requires proper accounting for polarization. Mopac2000 calculations can provide the necessary data for checking new force fields and/or parameter fitting.

  8. Immediate increases in quadriceps corticomotor excitability during an electromyography biofeedback intervention.

    Science.gov (United States)

    Pietrosimone, Brian; McLeod, Michelle M; Florea, David; Gribble, Phillip A; Tevald, Michael A

    2015-04-01

    The purpose of the study was to determine the effects of EMG-BF on vastus lateralis corticomotor excitability, measured via motor evoked potential (MEP) amplitudes elicited using Transcranial Magnetic Stimulation (TMS) during a maximal voluntary isometric contraction (MVIC). We also determined the effect of EMG-BF on isometric knee extensor strength. Fifteen healthy participants volunteered for this crossover study with two sessions held one-week apart. Participants were randomly assigned to condition order, during which five intervention MVICs were performed with or without EMG-BF. MEP amplitudes were collected with TMS during five knee extension contractions (5% of MVIC) at baseline and again during intervention MVICs within each session. During the control condition, participants were instructed to perform the same number of MVICs without any EMG-BF. Percent change scores were used to calculate the change in peak-to-peak MEP amplitudes that occurred during EMG-BF and Control MVICs compared to the baseline MEPs. Peak knee extension torque was recorded during MVICs prior to TMS for each condition. EMG-BF produced significantly increased MEP change scores and significantly greater torque than the control condition. The results of the current study suggest that EMG-BF may be a viable clinical method for targeting corticomotor excitability.

  9. Synthesis and structures of two cobalt compounds of 2-amino-2-methyl-1-propanol

    Indian Academy of Sciences (India)

    YONGJIE QIN; SHANSHAN YANG; LONG LIU; YUNING LIANG; ZILU CHEN

    2017-01-01

    The reactions of 2-amino-2-methyl-1-propanol (MepH) with Co(ClO₄) ₂•6H₂O in the presence of acetic acid gave [Co₂ (Mep) ₃ (OAc)(MepH)](ClO₄) ₂•MepH (1) and [CoIII ₄ CoII ₂ (Mep)8(μ₃-OH) ₂ (OAc) ₄](ClO₄) ₂• 2EtOH•2H₂O (2). They were characterized by elemental analysis, IR and single crystal X-ray diffraction analysis. Compound 1 presents a dinuclear structure with its two Co atoms linked by two Mep⁻ ligands and one acetate ligand. The two Co(II) and four Co(III) centers in 2 are held together by eight Mep⁻ ligands, two μ₃-OH⁻ ions and four acetate ligands to form a hexanuclear skeleton which contains a defected face-shared dicubane core. Their discrete polynuclear units are further linked into double-layered and mono-layered two-dimensional H-bonded framework, respectively.

  10. Synthesis, fluorescence properties of Eu(Ⅲ) complexes with novel carbazolefunctionalized β-diketone ligand

    Institute of Scientific and Technical Information of China (English)

    TANG Ruiren; ZHANG Wei; LUO Yiming; LI Jun

    2009-01-01

    A novel carbazole functionalized β-diketone, methyl 6-(9-ethylcarbazole-3-yl)-oxoacetyl-2-pyridinecarboxylate (MEP), and its Corresponding Corresponding binary Eu(Ⅲ) complexes Eu(MEP)32H2O and ternary complex Eu(MEP)3Phen with 1,10-Phenanthroline (Phen) were pre-pared. The ligand was characterized based on elemental analysis, FT-IR, and 1H NMR, and the complexes were characterized with elemental analysis, FT-IR and thermogravimetric and differential thermal analysis (TG-DTA). The investigation of fluorescence properties of the com-plexes Eu(MEP)32H2O and Eu(MEP)3Phen showed that the Eu(Ⅲ) ion could be sensitized efficiently by the ligand to some extent, in par-titular, in the ternary system, the secondary ligand Phen acting as a light-harvesting center was involved in the highly efficient energy transfer process, and the emission was stronger than the binary complex. In addition, the introduction of the carbazole moiety enlarged the π-conjugated system of the ligand and enhanced the luminescent intensity of the complexes.

  11. Maximal respiratory static pressures in patients with different stages of COPD severity

    Directory of Open Access Journals (Sweden)

    Ricci Alberto

    2008-01-01

    Full Text Available Abstract Background In this study, we analyzed maximal inspiratory pressure (MIP and maximal expiratory pressure (MEP values in a stable COPD population compared with normal subjects. We evaluated the possible correlation between functional maximal respiratory static pressures and functional and anthropometric parameters at different stages of COPD. Furthermore, we considered the possible correlation between airway obstruction and MIP and MEP values. Subject and methods 110 patients with stable COPD and 21 age-matched healthy subjects were enrolled in this study. Patients were subdivided according to GOLD guidelines: 31 mild, 39 moderate and 28 severe. Results Both MIP and MEP were lower in patients with severe airway impairment than in normal subjects. Moreover, we found a correlation between respiratory muscle function and some functional and anthropometric parameters: FEV1 (forced expiratory volume in one second, FVC (forced vital capacity, PEF (peak expiratory flow, TLC (total lung capacity and height. MIP and MEP values were lower in patients with severe impairment than in patients with a slight reduction of FEV1. Conclusion The measurement of MIP and MEP indicates the state of respiratory muscles, thus providing clinicians with a further and helpful tool in monitoring the evolution of COPD.

  12. Surface modification of Ni–Ti alloys for stent application after magnetoelectropolishing

    Energy Technology Data Exchange (ETDEWEB)

    Gill, Puneet; Musaramthota, Vishal; Munroe, Norman [Department of Mechanical and Materials Engineering, Florida International University, Miami, FL 33174 (United States); Datye, Amit [Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN 37916 (United States); Dua, Rupak [Department of Biomedical Engineering, Florida International University, Miami, FL 33174 (United States); Haider, Waseem [Mechanical Engineering, University of Texas-Pan American, TX (United States); McGoron, Anthony [Department of Biomedical Engineering, Florida International University, Miami, FL 33174 (United States); Rokicki, Ryszard [Electrobright, Macungie, PA 18062 (United States)

    2015-05-01

    The constant demand for new implant materials and the multidisciplinary design approaches for stent applications have expanded vastly over the past decade. The biocompatibility of these implant materials is a function of their surface characteristics such as morphology, surface chemistry, roughness, surface charge and wettability. These surface characteristics can directly influence the material's corrosion resistance and biological processes such as endothelialization. Surface morphology affects the thermodynamic stability of passivating oxides, which renders corrosion resistance to passivating alloys. Magnetoelectropolishing (MEP) is known to alter the morphology and composition of surface films, which assist in improving corrosion resistance of Nitinol alloys. This work aims at analyzing the surface characteristics of MEP Nitinol alloys by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The wettability of the alloys was determined by contact angle measurements and the mechanical properties were assessed by Nanoindentation. Improved mechanical properties were observed with the addition of alloying elements. Cyclic potentiodynamic polarization tests were performed to determine the corrosion susceptibility. Further, the alloys were tested for their cytotoxicity and cellular growth with endothelial cells. Improved corrosion resistance and cellular viability were observed with MEP surface treated alloys. - Highlights: • Magnetoelectropolishing (MEP) reduces the surface asperities of Nitinol alloys and formed stable oxides on the surface. • Improved corrosion resistance and reduced Nickel ion leaching were observed for MEP surfaces. • Ni–Ti alloyed with Cr showed improved mechanical properties. • Enhanced endothelial cell proliferation on ternary Nitinol alloys.

  13. Different Stimulation Frequencies Alter Synchronous Fluctuations in Motor Evoked Potential Amplitude of Intrinsic Hand Muscles-a TMS Study.

    Science.gov (United States)

    Sale, Martin V; Rogasch, Nigel C; Nordstrom, Michael A

    2016-01-01

    The amplitude of motor-evoked potentials (MEPs) elicited with transcranial magnetic stimulation (TMS) varies from trial-to-trial. Synchronous oscillations in cortical neuronal excitability contribute to this variability, however it is not known how different frequencies of stimulation influence MEP variability, and whether these oscillations are rhythmic or aperiodic. We stimulated the motor cortex with TMS at different regular (i.e., rhythmic) rates, and compared this with pseudo-random (aperiodic) timing. In 18 subjects, TMS was applied at three regular frequencies (0.05 Hz, 0.2 Hz, 1 Hz) and one aperiodic frequency (mean 0.2 Hz). MEPs (n = 50) were recorded from three intrinsic hand muscles of the left hand with different functional and anatomical relations. MEP amplitude correlation was highest for the functionally related muscle pair, less for the anatomically related muscle pair and least for the functionally- and anatomically-unrelated muscle pair. MEP correlations were greatest with 1 Hz, and least for stimulation at 0.05 Hz. Corticospinal neuron synchrony is higher with shorter TMS intervals. Further, corticospinal neuron synchrony is similar irrespective of whether the stimulation is periodic or aperiodic. These findings suggest TMS frequency is a crucial consideration for studies using TMS to probe correlated activity between muscle pairs.

  14. The Thermodynamics of Marine Biogeochemical Cycles: Lotka Revisited.

    Science.gov (United States)

    Vallino, Joseph J; Algar, Christopher K

    2016-01-01

    Nearly 100 years ago, Alfred Lotka published two short but insightful papers describing how ecosystems may organize. Principally, Lotka argued that ecosystems will grow in size and that their cycles will spin faster via predation and nutrient recycling so as to capture all available energy, and that evolution and natural selection are the mechanisms by which this occurs and progresses. Lotka's ideas have often been associated with the maximum power principle, but they are more consistent with recent developments in nonequilibrium thermodynamics, which assert that complex systems will organize toward maximum entropy production (MEP). In this review, we explore Lotka's hypothesis within the context of the MEP principle, as well as how this principle can be used to improve marine biogeochemistry models. We need to develop the equivalent of a climate model, as opposed to a weather model, to understand marine biogeochemistry on longer timescales, and adoption of the MEP principle can help create such models.

  15. Chaotic motif sampler: detecting motifs from biological sequences by using chaotic neurodynamics

    Science.gov (United States)

    Matsuura, Takafumi; Ikeguchi, Tohru

    Identification of a region in biological sequences, motif extraction problem (MEP) is solved in bioinformatics. However, the MEP is an NP-hard problem. Therefore, it is almost impossible to obtain an optimal solution within a reasonable time frame. To find near optimal solutions for NP-hard combinatorial optimization problems such as traveling salesman problems, quadratic assignment problems, and vehicle routing problems, chaotic search, which is one of the deterministic approaches, has been proposed and exhibits better performance than stochastic approaches. In this paper, we propose a new alignment method that employs chaotic dynamics to solve the MEPs. It is called the Chaotic Motif Sampler. We show that the performance of the Chaotic Motif Sampler is considerably better than that of the conventional methods such as the Gibbs Site Sampler and the Neighborhood Optimization for Multiple Alignment Discovery.

  16. Adjusting ammonium uptake via phosphorylation.

    Science.gov (United States)

    Lanquar, Viviane; Frommer, Wolf B

    2010-06-01

    In plants, AMT/MEP/Rh superfamily mediates high affinity ammonium uptake. AMT/MEP transporters form a trimeric complex, which requires a productive interaction between subunits in order to be functional. The AMT/MEP C-terminal domain is highly conserved in more than 700 AMT homologs from cyanobacteria to higher plants with no cases found to be lacking this domain. AMT1;1 exists in active and inactive states, probably controlled by the spatial positioning of the C-terminus. Ammonium triggers the phosphorylation of a conserved threonine residue (T460) in the C-terminus of AMT1;1 in a time- and concentration-dependent manner. The T460 phosphorylation level correlates with a decrease of root ammonium uptake. We propose that ammonium-induced phosphorylation modulates ammonium uptake as a general mechanism to protect against ammonium toxicity.

  17. Removing External Degrees of Freedom from Transition-State Search Methods using Quaternions

    CERN Document Server

    Melander, Marko; Jonsson, Hannes

    2015-01-01

    In finite systems, such as nanoparticles and gas-phase molecules, calculations of minimum energy paths (MEPs) connecting initial and final states of transitions as well as searches for saddle points are complicated by the presence of external degrees of freedom, such as overall translation and rotation. A method based on quaternion algebra for removing the external degrees of freedom is described here and applied in calculations using two commonly used methods: the nudged elastic band (NEB) method for MEPs and the DIMER method for finding the minimum mode in minimum mode following searches of first-order saddle points. With the quaternion approach, fewer images in the NEB are needed to represent MEPs accurately. In both NEB and DIMER calculations of finite systems, the number of iterations required to reach convergence is significantly reduced. The algorithms have been implemented in the Atomic Simulation Environment (ASE) open source software.

  18. A simple Chain-of-States method in acceleration space for the efficient location of Minimum Energy Paths

    CERN Document Server

    Hernandez, E R; Soler, J M

    2015-01-01

    We describe a robust and efficient chain-of-states method for computing Minimum Energy Paths~(MEPs) associated to barrier-crossing events in poly-atomic systems. The path is parametrized in terms of a continuous variable $t \\in [0,1]$ that plays the role of time. In contrast to previous chain-of-states algorithms such as the Nudged Elastic Band or String methods, where the positions of the states in the chain are taken as variational parameters in the search for the MEP, our strategy is to formulate the problem in terms of the second derivatives of the coordinates with respect to $t$, {\\em i.e.\\/} the state {\\em accelerations\\/}. We show this to result in a very transparent and efficient method for determining the MEP. We describe the application of the method in a series of test cases, including two low-dimensional problems and the Stone-Wales transformation in $\\mbox{C}_{60}$.

  19. Explaining reaction mechanisms using the dual descriptor: a complementary tool to the molecular electrostatic potential.

    Science.gov (United States)

    Martínez-Araya, Jorge Ignacio

    2013-07-01

    The intrinsic reactivity of cyanide when interacting with a silver cation was rationalized using the dual descriptor (DD) as a complement to the molecular electrostatic potential (MEP) in order to predict interactions at the local level. It was found that DD accurately explains covalent interactions that cannot be explained by MEP, which focuses on essentially ionic interactions. This allowed the rationalization of the reaction mechanism that yields silver cyanide in the gas phase. Other similar reaction mechanisms involving a silver cation interacting with water, ammonia, and thiosulfate were also explained by the combination of MEP and DD. This analysis provides another example of the usefulness of DD as a tool for gaining a deeper understanding of any reaction mechanism that is mainly governed by covalent interactions.

  20. Detoxification of methyl-parathion pesticide in aqueous solutions by electrochemical oxidation.

    Science.gov (United States)

    Arapoglou, D; Vlyssides, A; Israilides, C; Zorpas, A; Karlis, P

    2003-03-17

    Commercial methyl-parathion (MeP) was detoxified using an electrochemical method that employed a Ti/Pt anode and stainless steel 304 as cathode. Sodium chloride was added as electrolyte and the mixture was passed through an electrolytic cell for 2 h. Due to the strong oxidizing potential of the produced chemicals, the organic pollutants were wet oxidized to carbon dioxide and water. A number of experiments were run at laboratory scale. Reductions of COD and BOD(5) were both over 80% and the mean energy consumption was 18-8 kWh per kg(-1) COD reduced (COD(r)). The degradation of MeP was more effective when the pH of the brine solution was in the acid range than when it was in the alkaline range. From the results it can be concluded that electrolysis could be used as an oxidation pre-treatment stage for detoxification of toxic wastes with MeP.

  1. Phase-dependent modulation of corticospinal excitability during the observation of the initial phase of gait.

    Science.gov (United States)

    Takahashi, Makoto; Uchida, Natsuko; Yoshida, Mami; Liang, Nan; Nakazawa, Kimitaka; Sekikawa, Kiyokazu; Inamizu, Tsutomu; Hamada, Hironobu

    2014-12-01

    This study was undertaken to identify the temporal characteristics of corticospinal excitability of tibialis anterior muscle during the observation of the initial phase of gait. For this purpose, using transcranial magnetic stimulation, we recorded motor evoked potentials (MEPs) during the observation of the second step of an actor's first three steps of gait initiation with (complex gait) or without (normal gait) an obstacle and unstable surface. The results demonstrate that (1) MEPs during the observation of the initial phase of normal gait were significantly increased only at early swing phase, but not other phases (mid-swing, heel contact, mid-stance, and heel off) and (2) MEPs during the observation of the initial phase of complex gait were significantly increased at early swing and also at mid-swing and heel contact phases. These findings provide the first evidence that corticospinal excitability during the observation of gait, especially the initial phase, is modulated in phase- and motor-demanded-dependent manners.

  2. How multiplicity determines entropy and the derivation of the maximum entropy principle for complex systems

    CERN Document Server

    Hanel, Rudolf; Gell-Mann, Murray

    2014-01-01

    The maximum entropy principle (MEP) is a method for obtaining the most likely distribution functions of observables from statistical systems, by maximizing entropy under constraints. The MEP has found hundreds of applications in ergodic and Markovian systems in statistical mechanics, information theory, and statistics. For several decades there exists an ongoing controversy whether the notion of the maximum entropy principle can be extended in a meaningful way to non-extensive, non-ergodic, and complex statistical systems and processes. In this paper we start by reviewing how Boltzmann-Gibbs-Shannon entropy is related to multiplicities of independent random processes. We then show how the relaxation of independence naturally leads to the most general entropies that are compatible with the first three Shannon-Khinchin axioms, the (c,d)-entropies. We demonstrate that the MEP is a perfectly consistent concept for non-ergodic and complex statistical systems if their relative entropy can be factored into a general...

  3. Urinary excretion of phthalates and paraben after repeated whole-body topical application in humans

    DEFF Research Database (Denmark)

    Janjua, Nadeem Rezaq; Frederiksen, Hanne; Skakkebaek, Niels E

    2008-01-01

    were given a whole body topical application of basic cream 2 mg/cm(2) (control week) and then a cream containing 2% (w/w) of DEP, DBP and BP each (treatment week) daily. Twenty-four-hour urine samples were collected. Urinary total, and unconjugated BP, monoethyl phthalate (MEP) and monobutyl phthalate...... through dermal absorption, but there are no published data on absorption, metabolism, and excretion after dermal application. This study investigates urinary concentrations of BP and metabolites of DEP and DBP after topical application. In a 2-week single-blinded study, 26 healthy Caucasian male subjects...... (MBP) metabolites were analysed by Liquid Chromatography-Tandem Mass Spectroscopy (LC-MS/MS). All 26 subjects showed increased excretion of MEP, MBP and BP following topical application. Total MEP, MBP and BP (mean +/- SEM) excreted in urine in the treatment week were, respectively, 41 +/- 1.9, 11...

  4. Suppression of EMG activity by transcranial magnetic stimulation in human subjects during walking

    DEFF Research Database (Denmark)

    Petersen, Nicolas Caesar; Butler, Jane E; Marchand-Pauvert, Veronique

    2001-01-01

    1. The involvement of the motor cortex during human walking was evaluated using transcranial magnetic stimulation (TMS) of the motor cortex at a variety of intensities. Recordings of EMG activity in tibialis anterior (TA) and soleus muscles during walking were rectified and averaged. 2. TMS of low...... intensity (below threshold for a motor-evoked potential, MEP) produced a suppression of ongoing EMG activity during walking. The average latency for this suppression was 40.0 +/- 1.0 ms. At slightly higher intensities of stimulation there was a facilitation of the EMG activity with an average latency of 29.......5 +/- 1.0 ms. As the intensity of the stimulation was increased the facilitation increased in size and eventually a MEP was clear in individual sweeps. 3. In three subjects TMS was replaced by electrical stimulation over the motor cortex. Just below MEP threshold there was a clear facilitation at short...

  5. Corticospinal contribution to arm muscle activity during human walking

    DEFF Research Database (Denmark)

    Barthélemy, Dorothy; Nielsen, Jens Bo

    2010-01-01

    potentials (MEPs) elicited in the posterior deltoid muscle (PD) by transcranial magnetic stimulation (TMS) were modulated during the gait cycle in parallel with changes in the background EMG activity. There was no significant difference in the size of the MEPs at a comparable level of background EMG during...... walking and during static PD contraction. Short latency intracortical inhibition (SICI; 2 ms interval) studied by paired-pulse TMS was diminished during bursts of PD EMG activity. This could not be explained only by changes in background EMG activity and/or control MEP size, since SICI showed...... no correlation to the level of background EMG activity during static PD contraction. Finally, TMS at intensity below the threshold for activation of corticospinal tract fibres elicited a suppression of the PD EMG activity during walking. Since TMS at this intensity is likely to only activate intracortical...

  6. Comparison of clinical, magnetic resonance and evoked potentials data in a case of valproic-acid-related hyperammonemic coma

    Energy Technology Data Exchange (ETDEWEB)

    Hantson, Philippe [Universite Catholique de Louvain, Department of Intensive Care, Cliniques Saint-Luc, Brussels (Belgium); Grandin, Cecile; Duprez, Thierry [Universite Catholique de Louvain, Department of Neuroradiology, Cliniques Saint-Luc, Brussels (Belgium); Nassogne, Marie-Cecile [Universite Catholique de Louvain, Department of Pediatric Neurology, Cliniques Saint-Luc, Brussels (Belgium); Guerit, Jean-Michel [Universite Catholique de Louvain, Laboratory of Neurophysiology, Cliniques Saint-Luc, Brussels (Belgium)

    2005-01-01

    Magnetic resonance (MR) multimodality evoked potentials (MEPs) and clinical findings were correlated in a 47-year-old epileptic man in whom parenteral valproic acid (VPA) therapy induced severe comatose hyperammonemic encephalopathy without biological signs of hepatotoxicity (or hepatocytic dysfunction). Although the plasma VPA level remained within a normal therapeutic range, the ammoniemia increased to a toxic peak level at 411 {mu}mol/l 24 h after symptom onset, requiring VPA therapy discontinuation. Brain MR monitoring demonstrated early cytotoxic edema evolving into delayed vasogenic edema and final brain atrophy. Concomitantly to abnormalities within the brainstem on MR images, an increase in brainstem conduction at MEPs and clinical disturbance of brainstem reflexes were observed at the initial phase of the disease course. Later, the resolution of the MR and MEPs abnormalities paralleled the clinical recovery of the reflexes. (orig.)

  7. Nudged-elastic band method with two climbing images: finding transition states in complex energy landscapes

    CERN Document Server

    Zarkevich, Nikolai A

    2014-01-01

    The nudged-elastic band (NEB) method is modified with concomitant two climbing images (C2-NEB) to find a transition state (TS) in complex energy landscapes, such as those with serpentine minimal energy path (MEP). If a single climbing image (C1-NEB) successfully finds the TS, C2-NEB finds it with higher stability and accuracy. However, C2-NEB is suitable for more complex cases, where C1-NEB misses the TS because the MEP and NEB directions near the saddle point are different. Generally, C2-NEB not only finds the TS but guarantees that the climbing images approach it from the opposite sides along the MEP, and it estimates accuracy from the three images: the highest-energy one and its climbing neighbors. C2-NEB is suitable for fixed-cell NEB and the generalized solid-state NEB (SS-NEB).

  8. Terpenoids and Their Biosynthesis in Cyanobacteria

    Directory of Open Access Journals (Sweden)

    Bagmi Pattanaik

    2015-01-01

    Full Text Available Terpenoids, or isoprenoids, are a family of compounds with great structural diversity which are essential for all living organisms. In cyanobacteria, they are synthesized from the methylerythritol-phosphate (MEP pathway, using glyceraldehyde 3-phosphate and pyruvate produced by photosynthesis as substrates. The products of the MEP pathway are the isomeric five-carbon compounds isopentenyl diphosphate and dimethylallyl diphosphate, which in turn form the basic building blocks for formation of all terpenoids. Many terpenoid compounds have useful properties and are of interest in the fields of pharmaceuticals and nutrition, and even potentially as future biofuels. The MEP pathway, its function and regulation, and the subsequent formation of terpenoids have not been fully elucidated in cyanobacteria, despite its relevance for biotechnological applications. In this review, we summarize the present knowledge about cyanobacterial terpenoid biosynthesis, both regarding the native metabolism and regarding metabolic engineering of cyanobacteria for heterologous production of non-native terpenoids.

  9. The Thermodynamics of Marine Biogeochemical Cycles: Lotka Revisited

    Science.gov (United States)

    Vallino, Joseph J.; Algar, Christopher K.

    2016-01-01

    Nearly 100 years ago, Alfred Lotka published two short but insightful papers describing how ecosystems may organize. Principally, Lotka argued that ecosystems will grow in size and that their cycles will spin faster via predation and nutrient recycling so as to capture all available energy, and that evolution and natural selection are the mechanisms by which this occurs and progresses. Lotka's ideas have often been associated with the maximum power principle, but they are more consistent with recent developments in nonequilibrium thermodynamics, which assert that complex systems will organize toward maximum entropy production (MEP). In this review, we explore Lotka's hypothesis within the context of the MEP principle, as well as how this principle can be used to improve marine biogeochemistry models. We need to develop the equivalent of a climate model, as opposed to a weather model, to understand marine biogeochemistry on longer timescales, and adoption of the MEP principle can help create such models.

  10. Utility of magneto-electropolished ternary nitinol alloys for blood contacting applications.

    Science.gov (United States)

    Pulletikurthi, Chandan; Munroe, Norman; Stewart, Danique; Haider, Waseem; Amruthaluri, Sushma; Rokicki, Ryszard; Dugrot, Manuel; Ramaswamy, Sharan

    2015-10-01

    The thrombogenicity of a biomaterial is mainly dependent on its surface characteristics, which dictates its interactions with blood. Surface properties such as composition, roughness wettability, surface free energy, and morphology will affect an implant material's hemocompatibility. Additionally, in the realm of metallic biomaterials, the specific composition of the alloy and its surface treatment are important factors that will affect the surface properties. The utility of magneto-electropolished (MEP) ternary Nitinol alloys, NiTiTa, and NiTiCr as blood contacting materials was investigated. The hemcompatibility of these alloys were compared to mechanically polished (MP) metallic biomaterial counterparts. In vitro thrombogenicity tests revealed significantly less platelet adherence on ternary MEP Nitinol, especially MEP NiTi10Ta as compared to the MP metals (p Nitinol alloys can potentially be utilized for blood-contacting devices where, complications resulting from thrombogenicity can be minimized.

  11. Methanolic extract of Pterocarpus santalinus induces apoptosis in HeLa cells.

    Science.gov (United States)

    Kwon, H J; Hong, Y K; Kim, K H; Han, C H; Cho, S H; Choi, J S; Kim, Byung-Woo

    2006-04-21

    Ptercarpus santalinus (Fabaceae) has been used as a folk remedy in Korea, and it has been shown to exhibit antiinflammations, antiulcers and anticancer effects. In this study, therefore, we report the cytotoxic activity and the mechanism of cell death exhibited by the methanol extract of Ptercarpus santalinus (MEPS) against human cervical adenocarcinoma cell line, HeLa. Treatment of HeLa cells with various concentrations of MEPS resulted in growth inhibition and induction of apoptosis in a dose-dependent manner as determined by cell viability, chromatin condensation, DNA fragmentation and sub-G1 phase accumulation. In Western blot analysis, apoptosis in the HeLa cells was associated with the release of cytochrome C from mitochondria into the cytosol, activation of caspases-3, -8, -9 and proteolytic cleavage of PARP. These results suggest that MEPS exhibits antiproliferative effect on HeLa cells via apoptosis, and it may be a potential candidate in field of anticancer drug discovery.

  12. Female exposure to phthalates and time to pregnancy

    DEFF Research Database (Denmark)

    Ladehoff, Anne Marie; Riis, Anders H; Olsen, Jørn

    2017-01-01

    with prospective data based on 229 women from a Danish cohort of 430 first pregnancy planning couples enrolled in 1992-1994. In 2009, urinary analyses of phthalate metabolites were performed on stored urine samples from this cohort. PARTICIPANTS/MATERIALS, SETTING AND METHODS: We analyzed MEP, MBP, MBzP and MEHP......STUDY QUESTION: Is female exposure to phthalate metabolites associated with reduced fecundity, as estimated by prolonged time to pregnancy (TTP)? SUMMARY ANSWER: Female exposure to monoethyl phthalate (MEP) but not monobutyl phthalate (MBP), monobenzyl phthalate (MBzP) and monoethylhexyl phthalate...... to estimate fecundability ratios (FRs) and 95% CI in relation to the average urine metabolite concentration exposure level, controlled for age and BMI, and the time-varying variables smoking and alcohol. MAIN RESULT AND ROLE OF CHANCE: Urinary concentration of MEP was associated with a decreased fecundity...

  13. Pharmacokinetic Effects of Cinnamic Acid, Amygdalin, Glycyrrhizic Acid and Liquiritin on Ephedra Alkaloids in Rats.

    Science.gov (United States)

    Tang, Yinghong; Zheng, Mengkai; Chen, Yu-Lin; Chen, Jianzhen; He, Yu

    2017-06-01

    Ephedra alkaloids, including ephedrine (EP), pseudoephedrine (PEP) and methylephedrine (MEP), are sympathomimetic compounds with known toxicities but many Ephedra (Ephedrae herba) preparations, such as Ephedra decoction, have been clinically applied for centuries. In order to explore the possible detoxification mechanism of Ephedra alkaloids, four representative compounds in Ephedra decoction (cinnamic acid, amygdalin, glycyrrhizic acid and liquiritin) were studied for their pharmacokinetic effects on Ephedra alkaloids in Sprague-Dawley rats. Animals were randomly divided into six groups, with six rats in each. Rats were treated orally with EP-PEP-MEP (20 mg/kg EP + 20 mg/kg PEP + 20 mg/kg MEP) and different combinations of cinnamic acid (3.03 mg/kg), amygdalin (56.97 mg/kg), glycyrrhizic acid (12.42 mg/kg), liquiritin (3.79 mg/kg) with EP-PEP-MEP, and 20 mg/kg EP + 20 mg/kg PEP + 20 mg/kg MEP + 3.03 mg/kg cinnamic acid + 56.97 mg/kg amygdalin + 12.42 mg/kg glycyrrhizic acid + 3.79 mg/kg liquiritin. Blood samples (0.5 mL) were taken from the orbital sinus venous plexus into heparinized tubes at 5, 10, 20, 30, 45, 60, 90, 120, 180, 240, 300 and 360 min (6 rats per time point in each group) following single administration. The concentrations of Ephedra alkaloids in rat plasma were determined using a validated high performance liquid chromatography method. Area under the concentration-time curve from 0 to 360 min (AUC0-t ) of EP, PEP and MEP were 666.99, 650.76 and 632.37 µg·min/mL, respectively. Maximum plasma concentration (C max) of EP, PEP and MEP were 4.15, 4.08 and 3.59 μg/mL, respectively. Mean residence time (MRT) of EP, PEP and MEP were 197.00, 173.97 and 183.87 min, respectively, when the rats were treated with EP-PEP-MEP. Cinnamic acid increased the AUC0-t of EP while decreased C max of EP, amygdalin and glycyrrhizic acid increased C max and AUC0-t of EP and PEP, while liquiritin decreased AUC0-t of EP and PEP. The

  14. Maximum Entropy Production Modeling of Evapotranspiration Partitioning on Heterogeneous Terrain and Canopy Cover: advantages and limitations.

    Science.gov (United States)

    Gutierrez-Jurado, H. A.; Guan, H.; Wang, J.; Wang, H.; Bras, R. L.; Simmons, C. T.

    2015-12-01

    Quantification of evapotranspiration (ET) and its partition over regions of heterogeneous topography and canopy poses a challenge using traditional approaches. In this study, we report the results of a novel field experiment design guided by the Maximum Entropy Production model of ET (MEP-ET), formulated for estimating evaporation and transpiration from homogeneous soil and canopy. A catchment with complex terrain and patchy vegetation in South Australia was instrumented to measure temperature, humidity and net radiation at soil and canopy surfaces. Performance of the MEP-ET model to quantify transpiration and soil evaporation was evaluated during wet and dry conditions with independently and directly measured transpiration from sapflow and soil evaporation using the Bowen Ratio Energy Balance (BREB). MEP-ET transpiration shows remarkable agreement with that obtained through sapflow measurements during wet conditions, but consistently overestimates the flux during dry periods. However, an additional term introduced to the original MEP-ET model accounting for higher stomatal regulation during dry spells, based on differences between leaf and air vapor pressure deficits and temperatures, significantly improves the model performance. On the other hand, MEP-ET soil evaporation is in good agreement with that from BREB regardless of moisture conditions. The experimental design allows a plot and tree scale quantification of evaporation and transpiration respectively. This study confirms for the first time that the MEP-ET originally developed for homogeneous open bare soil and closed canopy can be used for modeling ET over heterogeneous land surfaces. Furthermore, we show that with the addition of an empirical function simulating the plants ability to regulate transpiration, and based on the same measurements of temperature and humidity, the method can produce reliable estimates of ET during both wet and dry conditions without compromising its parsimony.

  15. Transcutaneous spinal direct current stimulation modulates human corticospinal system excitability.

    Science.gov (United States)

    Bocci, Tommaso; Marceglia, Sara; Vergari, Maurizio; Cognetto, Valeria; Cogiamanian, Filippo; Sartucci, Ferdinando; Priori, Alberto

    2015-07-01

    This study aimed to assess the effects of thoracic anodal and cathodal transcutaneous spinal direct current stimulation (tsDCS) on upper and lower limb corticospinal excitability. Although there have been studies assessing how thoracic tsDCS influences the spinal ascending tract and reflexes, none has assessed the effects of this technique over upper and lower limb corticomotor neuronal connections. In 14 healthy subjects we recorded motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS) from abductor hallucis (AH) and hand abductor digiti minimi (ADM) muscles before (baseline) and at different time points (0 and 30 min) after anodal or cathodal tsDCS (2.5 mA, 20 min, T9-T11 level). In 8 of the 14 subjects we also tested the soleus H reflex and the F waves from AH and ADM before and after tsDCS. Both anodal and cathodal tsDCS left the upper limb MEPs and F wave unchanged. Conversely, while leaving lower limb H reflex unchanged, they oppositely affected lower limb MEPs: whereas anodal tsDCS increased resting motor threshold [(mean ± SE) 107.33 ± 3.3% increase immediately after tsDCS and 108.37 ± 3.2% increase 30 min after tsDCS compared with baseline] and had no effects on MEP area and latency, cathodal tsDCS increased MEP area (139.71 ± 12.9% increase immediately after tsDCS and 132.74 ± 22.0% increase 30 min after tsDCS compared with baseline) without affecting resting motor threshold and MEP latency. Our results show that tsDCS induces polarity-specific changes in corticospinal excitability that last for >30 min after tsDCS offset and selectively affect responses in lower limb muscles innervated by lumbar and sacral motor neurons.

  16. Task-concurrent anodal tDCS modulates bilateral plasticity in the human suprahyoid motor cortex

    Directory of Open Access Journals (Sweden)

    Shaofeng eZhao

    2015-06-01

    Full Text Available Transcranial direct current stimulation (tDCS is a non-invasive method to modulate cortical excitability in humans. Here, we examined the effects of anodal tDCS on suprahyoid motor evoked potentials (MEP when applied over the hemisphere with stronger and weaker suprahyoid/submental projections, respectively, while study participants performed a swallowing task. 30 healthy volunteers were invited to two experimental sessions and randomly assigned to one of two different groups. While in the first group stimulation was targeted over the hemisphere with stronger suprahyoid projections, the second group received stimulation over the weaker suprahyoid projections. tDCS was applied either as anodal or sham stimulation in a random cross-over design. Suprahyoid MEPs were assessed immediately before intervention, as well as 5, 30, 60, and 90 min after discontinuation of stimulation from both the stimulated and non-stimulated contralateral hemisphere. We found that anodal tDCS (a-tDCS had long-lasting effects on suprahyoid MEPs on the stimulated side in both groups (tDCS targeting the stronger projections: F(1,14 = 96.2, p < 0.001; tDCS targeting the weaker projections: F(1,14 = 37.45, p < 0.001. While MEPs did not increase when elicited from the non-targeted hemisphere after stimulation of the stronger projections (F(1,14 = 0.69, p = 0.42, we found increased MEPs elicited from the non-targeted hemisphere after stimulating the weaker projections (at time points 30 to 90 min (F(1,14 = 18.26, p = 0.001. We conclude that anodal tDCS has differential effects on suprahyoid MEPs elicited from the targeted and non-targeted hemisphere depending on the site of stimulation. This finding may be important for the application of a-tDCS in patients with dysphagia, for example after stroke.

  17. Real-time changes in corticospinal excitability related to motor imagery of a force control task.

    Science.gov (United States)

    Tatemoto, Tsuyoshi; Tsuchiya, Junko; Numata, Atsuki; Osawa, Ryuji; Yamaguchi, Tomofumi; Tanabe, Shigeo; Kondo, Kunitsugu; Otaka, Yohei; Sugawara, Kenichi

    2017-09-29

    To investigate real-time excitability changes in corticospinal pathways related to motor imagery in a changing force control task, using transcranial magnetic stimulation (TMS). Ten healthy volunteers learnt to control the contractile force of isometric right wrist dorsiflexion in order to track an on-screen sine wave form. Participants performed the trained task 40 times with actual muscle contraction in order to construct the motor image. They were then instructed to execute the task without actual muscle contraction, but by imagining contraction of the right wrist in dorsiflexion. Motor evoked potentials (MEPs), induced by TMS in the right extensor carpi radialis muscle (ECR) and flexor carpi radialis muscle (FCR), were measured during motor imagery. MEPs were induced at five time points: prior to imagery, during the gradual generation of the imaged wrist dorsiflexion (Increasing phase), the peak value of the sine wave, during the gradual reduction (Decreasing phase), and after completion of the task. The MEP ratio, as the ratio of imaged MEPs to resting-state, was compared between pre- and post-training at each time point. In the ECR muscle, the MEP ratio significantly increased during the Increasing phase and at the peak force of dorsiflexion imagery after training. Moreover, the MEP ratio was significantly greater in the Increasing phase than in the Decreasing phase. In the FCR, there were no significant consistent changes. Corticospinal excitability during motor imagery in an isometric contraction task was modulated in relation to the phase of force control after image construction. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Hemocompatibility Improvement of Chromium-Bearing Bare-Metal Stent Platform After Magnetoelectropolishing

    Science.gov (United States)

    Rokicki, Ryszard; Haider, Waseem; Maffi, Shivani Kaushal

    2015-01-01

    Research was undertaken to determine the influence of the increased content of chromium in the outermost passive layer of magneto-electrochemically refined Co-Cr alloy L-605 surface on its hemocompatibility. The chemistry, roughness, surface energy, and wettability of conventionally electropolished (EP) and magnetoelectropolished (MEP) samples were studied with x-ray photoelectron spectroscopy (XPS), open circuit potential, atomic force microscopy, and contact angle meter. In vitro hemocompatibility of tested material surfaces was assessed using two important indicators of vascular responses to biomaterial, namely endothelialization and platelets adhesion. The endothelialization was assessed by seeding and incubating samples with human umbilical vein endothelial cells (HUVEC) for 3 days before counting and observing them under a fluorescent microscope. The platelet (rich plasma blood) adhesion and activation test on EP and MEP L-605 alloy surfaces was assessed using a laser scanning confocal microscope. The XPS analysis of MEP samples showed significant enrichment of the passive layer with Cr and O when compared with the EP one. The amount of other elements in the passive layer did not show a significant difference between EP and MEP treatments. The adhesion of HUVEC cells shows remarkable affinity to surfaces enriched in Cr (MEP) with almost 100% confluency. In addition, the number of platelets that adhered to standard EP surfaces was higher compared to the MEP surface. The present study shows that the chromium-enriched surface of cobalt-chromium alloy L-605 by the magnetoelectropolishing process tremendously improves surface hemocompatibility with regard to stent functionality by enhanced endothelialization and lower platelet adhesion and should be taken under consideration as an alternative surface of biodegradable polymer drug-eluting stents, polymer-free drug-eluting stents as well as bare-metal stents.

  19. Counteracting negative venous line pressures to avoid arterial air bubbles: an experimental study comparing two different types of miniaturized extracorporeal perfusion systems.

    Science.gov (United States)

    Aboud, Anas; Mederos-Dahms, Hendrikje; Liebing, Kai; Zittermann, Armin; Schubert, Harald; Murray, Edward; Renner, Andre; Gummert, Jan; Börgermann, Jochen

    2015-05-29

    Because of its low rate of clinical complications, miniaturized extracorporeal perfusion systems (MEPS) are frequently used in heart centers worldwide. However, many recent studies refer to the higher probability of gaseous microemboli formation by MEPS, caused by subzero pressure values. This is the main reason why various de-airing devices were developed for today's perfusion systems. In the present study, we investigated the potential benefits of a simple one-way-valve connected to a volume replacement reservoir (OVR) for volume and pressure compensation. In an experimental study on 26 pigs, we compared MEPS (n = 13) with MEPS plus OVR (n = 13). Except OVR, perfusion equipment was identical in both groups. Primary endpoints were pressure values in the venous line and the right atrium as well as the number and volume of air bubbles. Secondary endpoints were biochemical parameters of systemic inflammatory response, ischemia, hemodilution and hemolysis. One animal was lost in the MEPS + OVR group. In the MEPS + OVR group no pressure values below -150 mmHg in the venous line and no values under -100 mmHg in right atrium were noticed. On the contrary, nearly 20% of venous pressure values in the MEPS group were below -150 and approximately 10% of right atrial pressure values were below -100 mmHg. Compared with the MEPS group, the bubble counter device showed lower numbers of arterial air bubbles in the MEPS + OVR group (mean ± SD: 13444 ± 5709 vs. 1 ± 2, respectively; p system with a volume replacement reservoir is able to counteract excessive negative venous line pressures and to reduce the number and volume of arterial air bubbles. This approach may lead to a lower rate of neurological complications.

  20. Combined monitoring of evoked potentials during microsurgery for lesions adjacent to the brainstem and intracranial aneurysms

    Institute of Scientific and Technical Information of China (English)

    KANG De-zhi; WU Zan-yi; LAN Qing; YU Liang-hong; LIN Zhang-ya; WANG Chen-yang; LIN Yuan-xiang

    2007-01-01

    Background Neurophysiologic monitoring during surgery is to prevent permanent neurological injury resulting from surgical manipulation. To improve the accuracy and sensitivity of intraoperative neuromonitoring, combined monitoring of transcranial electrical stimulation motor evoked potentials (TES-MEPs), somatosensory evoked potentials (SSEPs) and brainstem auditory evoked potentials (BAEPs) was attempted in microsurgery for lesions adjacent to the brainstem and intracranial aneurysms.Methods Monitoring of combined TES-MEPs with SSEPs was attempted in 68 consecutive patients with lesions adjacent to the brainstem as well as intracranial aneurysms. Among them, 31 patients (31 operations, 28 of posterior cranial fossa tumors, 3 of posterior circulation aneurysms) were also subjected to monitoring of BAEPs. The correlation of monitoring results and clinical outcome was studied prospectively.Results Combined monitoring of evoked potentials (EPs) was done in 64 (94.1%) of the 68 patients. MEPs monitoring was impossible for 4 patients (5.9%). No complication was observed during the combined monitoring in all the patients. In 45 (66.2%) of the 68 patients, EPs were stable, and they were neurologically intact. Motor dysfunction was detected by MEPs in 8 patients, SSEPs in 5, and BAEPs in 4, respectively.Conclusions A close relationship exists between postoperative motor function and the results of TES-MEPs monitoring.TES-MEPs are superior to SSEPs and BAEPs in detecting motor dysfunction, but combined EPs serve as a safe,effective and invasive method for intraoperative monitoring of the function of the motor nervous system. Monitoring of combined EPs during microsurgery for lesions adjacent to the brainstem and intracranial aneurysms may detect potentially hazardous maneuvers and improve the safety of subsequent procedures.

  1. Optimization of the IPP precursor supply for the production of lycopene, decaprenoxanthin and astaxanthin by Corynebacterium glutamicum

    Directory of Open Access Journals (Sweden)

    Sabine A.E. Heider

    2014-08-01

    Full Text Available The biotechnologically relevant bacterium C. glutamicum, currently used for the million ton-scale production of amino acids for the food and feed industries, is pigmented due to synthesis of the rare cyclic C50 carotenoid decaprenoxanthin and its glucosides. The precursors of carotenoid biosynthesis, isopenthenyl pyrophosphate (IPP and its isomer dimethylallyl pyrophosphate (DMAPP, are synthesized in this organism via the methylerythritol phosphate (MEP or non-mevalonate pathway. Terminal pathway engineering in recombinant C. glutamicum permitted the production of various nonnative C50 and C40 carotenoids. Here, the role of engineering isoprenoid precursor supply for lycopene production by C. glutamicum was characterized. Overexpression of dxs encoding the enzyme that catalyzes the first committed step of the MEP-pathway by chromosomal promoter exchange in a prophage-cured, genome-reduced C. glutamicum strain improved lycopene formation. Similarly, an increased IPP supply was achieved by chromosomal integration of two artificial operons comprising MEP pathway genes under the control of a constitutive promoter. Combined overexpression of dxs and the other six MEP pathways genes in C. glutamicum strain LYC3-MEP was not synergistic with respect to improving lycopene accumulation. Based on C. glutamicum strain LYC3-MEP astaxanthin could be produced in the mg per g cell dry weight range when the endogenous genes crtE, crtB and crtI for conversion of geranylgeranyl pyrophosphate to lycopene were coexpressed with the genes for lycopene cyclase and β-carotene hydroxylase from Pantoea ananatis and carotene C(4 oxygenase from Brevundimonas aurantiaca.

  2. Aberrant crossed corticospinal facilitation in muscles distant from a spinal cord injury.

    Directory of Open Access Journals (Sweden)

    Karen L Bunday

    Full Text Available Crossed facilitatory interactions in the corticospinal pathway are impaired in humans with chronic incomplete spinal cord injury (SCI. The extent to which crossed facilitation is affected in muscles above and below the injury remains unknown. To address this question we tested 51 patients with neurological injuries between C2-T12 and 17 age-matched healthy controls. Using transcranial magnetic stimulation we elicited motor evoked potentials (MEPs in the resting first dorsal interosseous, biceps brachii, and tibialis anterior muscles when the contralateral side remained at rest or performed 70% of maximal voluntary contraction (MVC into index finger abduction, elbow flexion, and ankle dorsiflexion, respectively. By testing MEPs in muscles with motoneurons located at different spinal cord segments we were able to relate the neurological level of injury to be above, at, or below the location of the motoneurons of the muscle tested. We demonstrate that in patients the size of MEPs was increased to a similar extent as in controls in muscles above the injury during 70% of MVC compared to rest. MEPs remained unchanged in muscles at and within 5 segments below the injury during 70% of MVC compared to rest. However, in muscles beyond 5 segments below the injury the size of MEPs increased similar to controls and was aberrantly high, 2-fold above controls, in muscles distant (>15 segments from the injury. These aberrantly large MEPs were accompanied by larger F-wave amplitudes compared to controls. Thus, our findings support the view that corticospinal degeneration does not spread rostral to the lesion, and highlights the potential of caudal regions distant from an injury to facilitate residual corticospinal output after SCI.

  3. Abnormal motor cortex excitability during linguistic tasks in adductor-type spasmodic dysphonia.

    Science.gov (United States)

    Suppa, A; Marsili, L; Giovannelli, F; Di Stasio, F; Rocchi, L; Upadhyay, N; Ruoppolo, G; Cincotta, M; Berardelli, A

    2015-08-01

    In healthy subjects (HS), transcranial magnetic stimulation (TMS) applied during 'linguistic' tasks discloses excitability changes in the dominant hemisphere primary motor cortex (M1). We investigated 'linguistic' task-related cortical excitability modulation in patients with adductor-type spasmodic dysphonia (ASD), a speech-related focal dystonia. We studied 10 ASD patients and 10 HS. Speech examination included voice cepstral analysis. We investigated the dominant/non-dominant M1 excitability at baseline, during 'linguistic' (reading aloud/silent reading/producing simple phonation) and 'non-linguistic' tasks (looking at non-letter strings/producing oral movements). Motor evoked potentials (MEPs) were recorded from the contralateral hand muscles. We measured the cortical silent period (CSP) length and tested MEPs in HS and patients performing the 'linguistic' tasks with different voice intensities. We also examined MEPs in HS and ASD during hand-related 'action-verb' observation. Patients were studied under and not-under botulinum neurotoxin-type A (BoNT-A). In HS, TMS over the dominant M1 elicited larger MEPs during 'reading aloud' than during the other 'linguistic'/'non-linguistic' tasks. Conversely, in ASD, TMS over the dominant M1 elicited increased-amplitude MEPs during 'reading aloud' and 'syllabic phonation' tasks. CSP length was shorter in ASD than in HS and remained unchanged in both groups performing 'linguistic'/'non-linguistic' tasks. In HS and ASD, 'linguistic' task-related excitability changes were present regardless of the different voice intensities. During hand-related 'action-verb' observation, MEPs decreased in HS, whereas in ASD they increased. In ASD, BoNT-A improved speech, as demonstrated by cepstral analysis and restored the TMS abnormalities. ASD reflects dominant hemisphere excitability changes related to 'linguistic' tasks; BoNT-A returns these excitability changes to normal.

  4. Transcranial magnetic stimulation with a half-sine wave pulse elicits direction-specific effects in human motor cortex

    Directory of Open Access Journals (Sweden)

    Jung Nikolai H

    2012-11-01

    Full Text Available Abstract Background Transcranial magnetic stimulation (TMS commonly uses so-called monophasic pulses where the initial rapidly changing current flow is followed by a critically dampened return current. It has been shown that a monophasic TMS pulse preferentially excites different cortical circuits in the human motor hand area (M1-HAND, if the induced tissue current has a posterior-to-anterior (PA or anterior-to-posterior (AP direction. Here we tested whether similar direction-specific effects could be elicited in M1-HAND using TMS pulses with a half-sine wave configuration. Results In 10 young participants, we applied half-sine pulses to the right M1-HAND which elicited PA or AP currents with respect to the orientation of the central sulcus. Measurements of the motor evoked potential (MEP revealed that PA half-sine stimulation resulted in lower resting motor threshold (RMT than AP stimulation. When stimulus intensity (SI was gradually increased as percentage of maximal stimulator output, the stimulus–response curve (SRC of MEP amplitude showed a leftward shift for PA as opposed to AP half-sine stimulation. Further, MEP latencies were approximately 1 ms shorter for PA relative to AP half-sine stimulation across the entire SI range tested. When adjusting SI to the respective RMT of PA and AP stimulation, the direction-specific differences in MEP latencies persisted, while the gain function of MEP amplitudes was comparable for PA and AP stimulation. Conclusions Using half-sine pulse configuration, single-pulse TMS elicits consistent direction-specific effects in M1-HAND that are similar to TMS with monophasic pulses. The longer MEP latency for AP half-sine stimulation suggests that PA and AP half-sine stimulation preferentially activates different sets of cortical neurons that are involved in the generation of different corticospinal descending volleys.

  5. Direct motor evoked potentials and cortical mapping using the NIM® nerve monitoring system: A technical note.

    Science.gov (United States)

    Bharadwaj, Suparna; Haji, Faizal; Hebb, Matthew; Chui, Jason

    2017-04-01

    Motor evoked potentials (MEPs) are commonly used to prevent neurological injury when operating in close proximity to the motor cortex or corticospinal pathway. We report a novel application of the NIM® nerve monitoring system (Medtronic@ NIM response 3.0) for intraoperative direct cortical (dc)-MEPs monitoring. A 69-year-old female patient presented with a 4month history of progressive left hemiparesis resulting from a large right sided posterior frontal meningioma that abutted and compressed the motor cortex. Motor cortical mapping and MEPs were indicated. The patient was anesthetized and maintained on total intravenous anesthetics. Compound muscle action potentials (CMAP) of the right upper limb were monitored using the NIM system. After a craniotomy was performed, we first used the Ojemann stimulator (monopolar) for dc-stimulation and then switched to use the monopolar nerve stimulator probe of the NIM system. The CMAP response was successfully elicited using the NIM stimulating probe (pulse width=250s, train frequency=7pulses/s, current=20mA). A gross total resection of the tumor was achieved with intermittent cortical mapping of MEPs. There were no intraoperative complications and the patient's motor function was preserved after the surgery. In this case, we reported the successful use of the NIM nerve monitoring system to elicit dc-MEPs under general anesthesia. The advantages of using this system include a simple set up and application, neurosurgeon familiarity, wide availability and lower cost. dc-MEPs can be achieved using the NIM system. We conclude that the NIM nerve monitoring system is a feasible alternative to standard neurophysiological monitoring systems. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Differences in supraspinal and spinal excitability during various force outputs of the biceps brachii in chronic- and non-resistance trained individuals.

    Directory of Open Access Journals (Sweden)

    Gregory E P Pearcey

    Full Text Available Motor evoked potentials (MEP and cervicomedullary evoked potentials (CMEP may help determine the corticospinal adaptations underlying chronic resistance training-induced increases in voluntary force production. The purpose of the study was to determine the effect of chronic resistance training on corticospinal excitability (CE of the biceps brachii during elbow flexion contractions at various intensities and the CNS site (i.e. supraspinal or spinal predominantly responsible for any training-induced differences in CE. Fifteen male subjects were divided into two groups: 1 chronic resistance-trained (RT, (n = 8 and 2 non-RT, (n = 7. Each group performed four sets of ∼5 s elbow flexion contractions of the dominant arm at 10 target forces (from 10%-100% MVC. During each contraction, subjects received 1 transcranial magnetic stimulation, 2 transmastoid electrical stimulation and 3 brachial plexus electrical stimulation, to determine MEP, CMEP and compound muscle action potential (Mmax amplitudes, respectively, of the biceps brachii. All MEP and CMEP amplitudes were normalized to Mmax. MEP amplitudes were similar in both groups up to 50% MVC, however, beyond 50% MVC, MEP amplitudes were lower in the chronic RT group (p<0.05. CMEP amplitudes recorded from 10-100% MVC were similar for both groups. The ratio of MEP amplitude/absolute force and CMEP amplitude/absolute force were reduced (p<0.012 at all contraction intensities from 10-100% MVC in the chronic-RT compared to the non-RT group. In conclusion, chronic resistance training alters supraspinal and spinal excitability. However, adaptations in the spinal cord (i.e. motoneurone seem to have a greater influence on the altered CE.

  7. Brain-robot interface driven plasticity: Distributed modulation of corticospinal excitability.

    Science.gov (United States)

    Kraus, Dominic; Naros, Georgios; Bauer, Robert; Leão, Maria Teresa; Ziemann, Ulf; Gharabaghi, Alireza

    2016-01-15

    Brain-robot interfaces (BRI) are studied as novel interventions to facilitate functional restoration in patients with severe and persistent motor deficits following stroke. They bridge the impaired connection in the sensorimotor loop by providing brain-state dependent proprioceptive feedback with orthotic devices attached to the hand or arm of the patients. The underlying neurophysiology of this BRI neuromodulation is still largely unknown. We investigated changes of corticospinal excitability with transcranial magnetic stimulation in thirteen right-handed healthy subjects who performed 40min of kinesthetic motor imagery receiving proprioceptive feedback with a robotic orthosis attached to the left hand contingent to event-related desynchronization of the right sensorimotor cortex in the β-band (16-22Hz). Neural correlates of this BRI intervention were probed by acquiring the stimulus-response curve (SRC) of both motor evoked potential (MEP) peak-to-peak amplitudes and areas under the curve. In addition, a motor mapping was obtained. The specificity of the effects was studied by comparing two neighboring hand muscles, one BRI-trained and one control muscle. Robust changes of MEP amplitude but not MEP area occurred following the BRI intervention, but only in the BRI-trained muscle. The steep part of the SRC showed an MEP increase, while the plateau of the SRC showed an MEP decrease. MEP mapping revealed a distributed pattern with a decrease of excitability in the hand area of the primary motor cortex, which controlled the BRI, but an increase of excitability in the surrounding somatosensory and premotor cortex. In conclusion, the BRI intervention induced a complex pattern of modulated corticospinal excitability, which may boost subsequent motor learning during physiotherapy.

  8. Bilateral sensory deprivation of trigeminal afferent fibres on corticomotor control of human tongue musculature: a preliminary study.

    Science.gov (United States)

    Kothari, M; Baad-Hansen, L; Svensson, P

    2016-09-01

    Transcranial magnetic stimulation (TMS) has demonstrated changes in motor evoked potentials (MEPs) in human limb muscles following modulation of sensory afferent inputs. The aim of this study was to determine whether bilateral local anaesthesia (LA) of the lingual nerve affects the excitability of the tongue motor cortex (MI) as measured by TMS. The effect on MEPs after bilateral LA of the lingual nerve was studied, while the first dorsal interosseous (FDI) muscle served as a control in ten healthy participants. MEPs were measured on the right side of the tongue dorsum in four different conditions: (i) immediately prior to anaesthesia (baseline), (ii) during bilateral LA block of the lingual nerve, (iii) after anaesthesia had subjectively subsided (recovery) and (iv) 3 h after bilateral lingual block injection. MEPs were assessed using stimulus-response curves in steps of 10% of motor threshold (T). Eight stimuli were given at each stimulus level. The amplitudes of the tongue MEPs were significantly influenced by the stimulus intensity (P < 0·001) but not by condition (P = 0·186). However, post hoc tests showed that MEPS were statistically significantly higher during bilateral LA block condition compared with baseline at T + 40%, T + 50% and T + 60% (P < 0·028) and also compared with recovery at T + 60% (P = 0·010) as well as at 3 h after injection at T + 50% and T + 60% (P < 0·029). Bilateral LA block of the lingual nerve seems to be associated with a facilitation of the corticomotor pathways related to the tongue musculature.

  9. Theory of using magnetic deflections to combine charged particle beams

    Energy Technology Data Exchange (ETDEWEB)

    Steckbeck, Mackenzie K. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Doyle, Barney Lee [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-09-01

    Several radiation effects projects in the Ion Beam Lab (IBL) have recently required two disparate charged particle beams to simultaneously strike a single sample through a single port of the target chamber. Because these beams have vastly different mass–energy products (MEP), the low-MEP beam requires a large angle of deflection toward the sample by a bending electromagnet. A second electromagnet located further upstream provides a means to compensate for the small angle deflection experienced by the high-MEP beam during its path through the bending magnet. This paper derives the equations used to select the magnetic fields required by these two magnets to achieve uniting both beams at the target sample. A simple result was obtained when the separation of the two magnets was equivalent to the distance from the bending magnet to the sample, and the equation is given by: Bs= 1/2(rc/rs) Bc, where Bs and Bc are the magnetic fields in the steering and bending magnet and rc/rs is the ratio of the radii of the bending magnet to that of the steering magnet. This result is not dependent upon the parameters of the high MEP beam, i.e. energy, mass, charge state. Therefore, once the field of the bending magnet is set for the low-MEP beam, and the field in the steering magnet is set as indicted in the equation, the trajectory path of any high-MEP beam will be directed into the sample.

  10. Pre-stimulus Alpha Oscillations and Inter-subject Variability of Motor Evoked Potentials in Single- and Paired-Pulse TMS Paradigms

    Science.gov (United States)

    Iscan, Zafer; Nazarova, Maria; Fedele, Tommaso; Blagovechtchenski, Evgeny; Nikulin, Vadim V.

    2016-01-01

    Inter- and intra-subject variability of the motor evoked potentials (MEPs) to TMS is a well-known phenomenon. Although a possible link between this variability and ongoing brain oscillations was demonstrated, the results of the studies are not consistent with each other. Exploring this topic further is important since the modulation of MEPs provides unique possibility to relate oscillatory cortical phenomena to the state of the motor cortex probed with TMS. Given that alpha oscillations were shown to reflect cortical excitability, we hypothesized that their power and variability might explain the modulation of subject-specific MEPs to single- and paired-pulse TMS (spTMS, ppTMS, respectively). Neuronal activity was recorded with multichannel electroencephalogram. We used spTMS and two ppTMS conditions: intracortical facilitation (ICF) and short-interval intracortical inhibition (SICI). Spearman correlations were calculated within and across subjects between MEPs and the pre-stimulus power of alpha oscillations in low (8–10 Hz) and high (10–12 Hz) frequency bands. Coefficient of quartile variation was used to measure variability. Across-subject analysis revealed no difference in the pre-stimulus alpha power among the TMS conditions. However, the variability of high-alpha power in spTMS condition was larger than in the SICI condition. In ICF condition pre-stimulus high-alpha power variability correlated positively with MEP amplitude variability. No correlation has been observed between the pre-stimulus alpha power and MEP responses in any of the conditions. Our results show that the variability of the alpha oscillations can be more predictive of TMS effects than the commonly used power of oscillations and we provide further support for the dissociation of high and low-alpha bands in predicting responses produced by the stimulation of the motor cortex. PMID:27774060

  11. Reference: 86 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available es. Analysis of mutants during embryogenesis allows differentiation between CLB genes that act nonce...erved in embryos, and those that act cell autonomously, where complementation during embryogenesis is not ob...served. Molecular characterization of the noncell autonomous clb4 mutant established that the CLB4 gene enco...the last enzyme of the methylerythritol 4-phosphate (MEP) pathway for the synthesis of plastidic isoprenoids. The nonce...een tissues, and provides in vivo evidence that some movement of MEP intermediate

  12. Measurably evolving populations

    DEFF Research Database (Denmark)

    Drummond, Alexei James; Pybus, Oliver George; Rambaut, Andrew

    2003-01-01

    processes through time. Populations for which such studies are possible � measurably evolving populations (MEPs) � are characterized by sufficiently long or numerous sampled sequences and a fast mutation rate relative to the available range of sequence sampling times. The impact of sequences sampled through...... time has been most apparent in the disciplines of RNA viral evolution and ancient DNA, where they enable us to estimate divergence times without paleontological calibrations, and to analyze temporal changes in population size, population structure and substitution rates. Thus, MEPs could increase our...

  13. The two-box model of climate: limitations and applications to planetary habitability and maximum entropy production studies.

    Science.gov (United States)

    Lorenz, Ralph D

    2010-05-12

    The 'two-box model' of planetary climate is discussed. This model has been used to demonstrate consistency of the equator-pole temperature gradient on Earth, Mars and Titan with what would be predicted from a principle of maximum entropy production (MEP). While useful for exposition and for generating first-order estimates of planetary heat transports, it has too low a resolution to investigate climate systems with strong feedbacks. A two-box MEP model agrees well with the observed day : night temperature contrast observed on the extrasolar planet HD 189733b.

  14. Effect of surfactants on the morphology of FeSe films fabricated from a single source precursor by aerosol assisted chemical vapour deposition

    Indian Academy of Sciences (India)

    Raja Azadar Hussain; Amin Badshah; Naghma Haider; Malik Dilshad Khan; Bhajan Lal

    2015-03-01

    This article presents the fabrication of FeSe thin films from a single source precursor namely (1-(2-fluorobenzoyl)-3-(4-ferrocenyl-3-methylphenyl)selenourea (MeP2F)) by aerosol assisted chemical vapour deposition (AACVD). All the films were prepared via similar experimental conditions (temperature, flow rate, concentration, solvent system and reactor type) except the use of three different concentrations of two different surfactants i.e., triton and span. Seven thin films were characterized with PXRD, SEM, AFM, EDS and EDS mapping. The mechanism of the interaction of surfactant with MeP2F was determined with cyclic voltammetry (CV) and UV-Vis spectroscopy.

  15. Reference: 507 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available Keiko et al. 2007 Feb. Plant Cell Physiol. 48(2):322-31. Higher plants have two metabolic pathways for isopr...espite the compartmentalization of these two pathways, metabolic flow occurs betw...een them. However, little is known about the mechanisms that regulate the two pathways and the metabolic cro...lomazone, inhibitors of the MVA and MEP pathways, respectively. The accumulation of the major products of these pathways...be involved in isoprenoid biosynthesis in both the MVA and MEP pathways. Lovastatin insensitive 1, a Novel p

  16. Confronting Regulatory Cost and Quality Expectations. An Exploration of Technical Change in Minimum Efficiency Performance Standards

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Margaret [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Stanford Univ., CA (United States); Spurlock, C. Anna [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Yang, Hung-Chia [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2015-09-21

    The dual purpose of this project was to contribute to basic knowledge about the interaction between regulation and innovation and to inform the cost and benefit expectations related to technical change which are embedded in the rulemaking process of an important area of national regulation. The area of regulation focused on here is minimum efficiency performance standards (MEPS) for appliances and other energy-using products. Relevant both to U.S. climate policy and energy policy for buildings, MEPS remove certain product models from the market that do not meet specified efficiency thresholds.

  17. Offsite Source Recovery Program (OSRP) Workshop Module: Tianjin, China, July 16-July 17, 2012

    Energy Technology Data Exchange (ETDEWEB)

    Houlton, Robert J. [Los Alamos National Laboratory

    2012-07-11

    Recovering and disposal of radioactive sources that are no longer in service in their intended capacity is an area of high concern Globally. A joint effort to recover and dispose of such sources was formed between the US Department of Energy and the Chinese Ministry of Environmental Protection (MEP), in preparation for the 2008 Beijing Olympics. LANL involvement in this agreement continues today under the DOE-Global Threat Reduction Initiative (GTRI) program. LANL will be presenting overview information on their Offsite Source Recovery (OSRP) and Source Disposal programs, in a workshop for the Ministry of Environmental Protection (MEP) at Tianjin, China, on July 16 and 17, 2012.

  18. Mesoscale hydrological ensemble forecasting for water resources management

    Energy Technology Data Exchange (ETDEWEB)

    Fortin, V. [Meteorological Research Div., Environment Canada, Dorval, Quebec (Canada); Turcotte, R. [Government of Quebec, Centre of Quebec' s Water Expertise, Quebec (Canada); Anctil, F. [Univ. Laval, Dept. of Civil Engineering, Laval, Quebec (Canada); Favre, A.-C. [INRS, Water Earth and Environment, Quebec (Canada); Petit, Th. [Univ. Laval, Dept. of Civil Engineering, Laval, Quebec (Canada)

    2008-07-01

    This poster discusses meso-scale hydrological ensemble forecasting for water resources management. Environment Canada will produce a 20 member meso-scale (35 km), short range (48 h) meteorological ensemble prediction system (M-EPS). Each of the 20 members of the global EPS will be dynamically down scaled from 100 to 35 km over North America using limited area model GEM-LAM. Preliminary tests have been conducted on Lie'vre watershed to assess the impact of using short range M-EPS for hydrological forecasting.

  19. Delayed focal involvement of upper motor neurons in the Madras pattern of motor neuron disease.

    Science.gov (United States)

    Massa, R; Scalise, A; Iani, C; Palmieri, M G; Bernardi, G

    1998-12-01

    We report the case of a young man from the south of India, initially presenting the typical signs of benign monomelic amyotrophy (BMA) in the left upper limb. After several years, the involvement of other limbs and the appearance of bulbar signs suggested the possible diagnosis of the Madras pattern of motor neuron disease (MMND). Serial motor evoked potential (MEP) recordings allowed detection of the onset of a focal involvement of upper motor neurons (UMN) controlling innervation in the originally amyotrophic limb. Therefore, serial MEP recordings can be useful for the early detection of sub-clinical UMN damage in motor neuron disease presenting with pure lower motor neuron (LMN) signs.

  20. Comparison of Test Procedures and Energy Efficiency Criteria in Selected International Standards & Labeling Programs for Copy Machines, External Power Supplies, LED Displays, Residential Gas Cooktops and Televisions

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Nina [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Zhou, Nan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Fridley, David [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2012-03-01

    This report presents a technical review of international minimum energy performance standards (MEPS), voluntary and mandatory energy efficiency labels and test procedures for five products being considered for new or revised MEPS in China: copy machines, external power supply, LED displays, residential gas cooktops and flat-screen televisions. For each product, an overview of the scope of existing international standards and labeling programs, energy values and energy performance metrics and description and detailed summary table of criteria and procedures in major test standards are presented.

  1. Voluntary activation of ankle muscles is accompanied by subcortical facilitation of their antagonists

    DEFF Research Database (Denmark)

    Geertsen, Svend Sparre; Zuur, Abraham T.; Nielsen, Jens Bo

    2010-01-01

    Flexion and extension movements are organized reciprocally, so that extensor motoneurones in the spinal cord are inhibited when flexor muscles are active and vice versa. During and just prior to dorsiflexion of the ankle, soleus motoneurones are thus inhibited as evidenced by a depression...... MEPs were also facilitated (although to a lesser extent) at a similar time in relation to the onset of dorsiflexion. TA MEPs were facilitated 50 ms prior to onset of dorsiflexion and neither depressed nor facilitated prior to plantar flexion. No difference was found between the facilitation...

  2. Effect of Enzyme Inhibitors on Terpene Trilactones Biosynthesis and Gene Expression Profiling in Ginkgo biloba Cultured Cells.

    Science.gov (United States)

    Chen, Lijia; Tong, Hui; Wang, Mingxuan; Zhu, Jianhua; Zi, Jiachen; Song, Liyan; Yu, Rongmin

    2015-12-01

    The biosynthetic pathway of terpene trilactones of Ginkgo biloba is unclear. In this present study, suspension cultured cells of G. biloba were used to explore the regulation of the mevalonic acid (MVA) and methylerythritol 4-phosphate (MEP) pathways in response to specific enzyme inhibitors (lovastatin and clomazone). The results showed that the biosynthesis of bilobalide was more highly correlated with the MVA pathway, and the biosynthesis of ginkgolides was more highly correlated with the MEP pathway. Meanwhile, according to the results, it could be speculated that bilobalide might be a product of ginkgolide metabolism.

  3. [Fragment reaction catalyzed by E. coli ribosomes].

    Science.gov (United States)

    Kotusov, V V; Kukhanova, M K; Sal'nikova, N E; Nikolaeva, L V; Kraevskiĭ, A A

    1977-01-01

    It has been shown that 50S subunits of E. coli MRE-600 ribosomes catalyze the reaction of N-(formyl)-methionyl ester of adenosine 5'-phosphate acting as peptide donor, with Phe-tRNA or CACCA-Phe serving as a peptide acceptor. The reaction is stimulated by cytidine 5'phosphate and inhibited by lincomycin, puromycin and chloramphenicol. The obtained results show that the structure of the donor site of peptidyltransferase is completely assembled on the 50S subunit and 30S subunit is not required for its formation.

  4. Structure of dimeric, recombinant Sulfolobus solfataricus phosphoribosyl diphosphate synthase

    DEFF Research Database (Denmark)

    Andersen, Rune W.; Lo Leggio, Leila; Hove-Jensen, Bjarne

    2015-01-01

    The enzyme 5-phosphoribosyl-1-α-diphosphate (PRPP) synthase (EC 2.7.6.1) catalyses the Mg2+-dependent transfer of a diphosphoryl group from ATP to the C1 hydroxyl group of ribose 5-phosphate resulting in the production of PRPP and AMP. A nucleotide sequence specifying Sulfolobus solfataricus PRPP...... PRPP synthase as a search model. The two amino acid sequences share 35 % identity. The resulting asymmetric unit consists of three separated dimers. The protein was co-crystallised in the presence of AMP and ribose 5-phosphate, but in the electron density map of the active site only AMP and a sulphate...

  5. Labor Supply of Politicians

    DEFF Research Database (Denmark)

    Fisman, Raymond; Harmon, Nikolaj Arpe; Kamenica, Emir

    Using data on Members of the European Parliament (MEPs), we examine the impact of salaries on the composition and the behavior of legislators. Employing a differences-in-differences approach, we exploit the introduction of a law that equalized MEPs’ salaries which had previously differed by as much...

  6. Labor Supply of Politicians

    DEFF Research Database (Denmark)

    Fisman, Raymond; Harmon, Nikolaj Arpe; Kamenica, Emir

    2015-01-01

    Using data on Members of the European Parliament (MEPs), we examine the impact of salaries on the composition and the behavior of legislators. Employing a differences-in-differences approach, we exploit the introduction of a law that equalized MEPs’ salaries which had previously differed by as much...

  7. Respiratory muscle strength and aerobic performance of wheelchair basketball players

    Directory of Open Access Journals (Sweden)

    Raphael N. Pereira

    Full Text Available Abstract The respiratory system has been described as a limiting factor in the performance of athletes. Therefore, the objective of this study was to evaluate the relationship between the respiratory muscle strength (RMS and aerobic performance of wheelchair basketball players (WCBPs. We evaluated 19 male WCBPs who were divided into two groups: trunk control group (TCG and without trunk control group (WTCG. All participants underwent a pulmonary function test, evaluation of maximal inspiratory (MIP and expiratory (MEP pressures, and an aerobic performance test. The MIP of both groups and the MEP values of TCG exceeded the predicted values for age and gender. No differences were observed in the MIP and aerobic performance between the groups although a difference was observed in the MEP values. Positive correlations were observed between MIP/MEP and the aerobic performance for both groups. These results suggested that the overall RMS of this group of WCBPs fell within or above the predicted values. Hence, the study concluded that RMS can positively influence the aerobic performance of WCBP.

  8. Characteristics and Antitumor Activity of Morchella esculenta Polysaccharide Extracted by Pulsed Electric Field

    Directory of Open Access Journals (Sweden)

    Chao Liu

    2016-06-01

    Full Text Available Polysaccharides from Morchella esculenta have been proven to be functional and helpful for humans. The purpose of this study was to investigate the chemical structure and anti-proliferating and antitumor activities of a Morchella esculenta polysaccharide (MEP extracted by pulsed electric field (PEF in submerged fermentation. The endo-polysaccharide was separated and purified by column chromatography and Gel permeation chromatography, and analyzed by gas chromatography. The MEP with an average molecular weight of 81,835 Da consisted of xylose, glucose, mannose, rhamnose and galactose at the ratio of 5.4:5.0:6.5:7.8:72.3. Structure of MEP was further analyzed by Fourier-transform infrared spectroscopy and 1H and 13C liquid-state nuclear magnetic resonance spectroscopy. Apoptosis tests proved that MEP could inhibit the proliferation and growth of human colon cancer HT-29 cells in a time- and dose-dependent manner within 48 h. This study provides more information on chemical structure of anti-proliferating polysaccharides isolated from Morchella esculenta.

  9. Characteristics and Antitumor Activity of Morchella esculenta Polysaccharide Extracted by Pulsed Electric Field.

    Science.gov (United States)

    Liu, Chao; Sun, Yonghai; Mao, Qian; Guo, Xiaolei; Li, Peng; Liu, Yang; Xu, Na

    2016-06-22

    Polysaccharides from Morchella esculenta have been proven to be functional and helpful for humans. The purpose of this study was to investigate the chemical structure and anti-proliferating and antitumor activities of a Morchella esculenta polysaccharide (MEP) extracted by pulsed electric field (PEF) in submerged fermentation. The endo-polysaccharide was separated and purified by column chromatography and Gel permeation chromatography, and analyzed by gas chromatography. The MEP with an average molecular weight of 81,835 Da consisted of xylose, glucose, mannose, rhamnose and galactose at the ratio of 5.4:5.0:6.5:7.8:72.3. Structure of MEP was further analyzed by Fourier-transform infrared spectroscopy and ¹H and (13)C liquid-state nuclear magnetic resonance spectroscopy. Apoptosis tests proved that MEP could inhibit the proliferation and growth of human colon cancer HT-29 cells in a time- and dose-dependent manner within 48 h. This study provides more information on chemical structure of anti-proliferating polysaccharides isolated from Morchella esculenta.

  10. Screening for Attrition and Performance with Non-Cognitive Measures

    Science.gov (United States)

    2010-01-27

    including: – - – Even-tempered – Intellectual efficiency – – Attention seeking Which of these statements TAPAS is most like you? • I like roller ... coasters . • I enjoy parties. • Computer-adaptive test delivered on the CAT-ASVAB platform at MEPS • Paired forced choice self descriptors • TAPAS

  11. Klippel-Feil syndrome for scoliosis surgery: management of a ...

    African Journals Online (AJOL)

    2011-05-23

    May 23, 2011 ... cervical motion from fusion and cervical instability renders intubation difficult ... MEP, resulting in postoperative paraplegia. Case report ... Blood investigations were within normal limits, with ... After adequate depth of anaesthesia was achieved, IV fentanyl 2 .... features and current understanding of etiology.

  12. Modulation of sensory inhibition of motor evoked potentials elicited by TMS prior to movement?

    DEFF Research Database (Denmark)

    Leukel, Christian; Lundbye-Jensen, Jesper; Nielsen, Jens Bo

    Short latency afferent inhibition (SAI) refers to a decrement of the size of a motor evoked potential (MEP) by transcranial magnetic stimulation (TMS) after electrical stimulation of a peripheral afferent nerve (PNS) (Tokimura et al. 2000). Since SAI occurs when TMS is applied at the time...

  13. Changes of evoked potential and expression of nestin in subventricular zones in rats after focal cerebral ischemia

    Institute of Scientific and Technical Information of China (English)

    GAO Jie; WANG Yong-tang; WANG Li-li; ZENG Ling; WU Ya-min; SHAO Yang

    2007-01-01

    Objective:To study the characteristics of latency of somatosensory evoked potential (SEP)and motor evoked potential (MEP) and the expression of nestin in subventricular zones (SVZ) after persistent focal cerebral ischemia in rats. Methods: The model of cerebral ischemia in rats was made by middle cerebral artery occlusion (MCAO). All animals of ischemia were sacrificed after 12 h, 1 d, 3 d, 7 d,and 14 d to observe the changes of latency of SEP and MEP and to detect the expression of nestin, with an immunohistochemical approach. Results: The latencies of P1 (positive wave 1), N1 (negative wave 1) and P2 (positive wave 2) in SEP were significantly prolonged after MCAO. The latencies of N1 and N2 waves in MEP were postponed gradually and no statistical difference of latency of N1 wave was found in rats at 7d and 14 d after MCAO. The expression of nestin increased at 12 h, and showed a significant augmentation at 3 d and peaked at 7 d, then declined slightly at 14 d after MCAO. Conclusion: The cerebral ischemia prolonged the latency of EP waves and the expression of nestin was up-regulated and reached the peak at 7d, showing the ischemia induced the proliferation of nervous stem cells. The SEP and MEP may evaluate the proliferation in SVZ after brain ischemia.

  14. Reliability of surface electromyography measurements from the suprahyoid muscle complex.

    Science.gov (United States)

    Kothari, M; Stubbs, P W; Pedersen, A R; Jensen, J; Nielsen, J F

    2017-09-01

    Assessment of swallowing musculature using motor evoked potentials (MEPs) can be used to evaluate neural pathways. However, recording of the swallowing musculature is often invasive, uncomfortable and unrealistic in normal clinical practice. To investigate the possibility of using the suprahyoid muscle complex (SMC) using surface electromyography (sEMG) to assess changes to neural pathways by determining the reliability of measurements in healthy participants over days. Seventeen healthy participants were recruited. Measurements were performed twice with one week between sessions. Single-pulse (at 120% and 140% of the resting motor threshold (rMT)) and paired-pulse (2 ms and 15 ms paired pulse) transcranial magnetic stimulation (TMS) were used to elicit MEPs in the SMC which were recorded using sEMG. ≈50% of participants (range: 42-58%; depending on stimulus type/intensity) had significantly different MEP values between day 1 and day 2 for single-pulse and paired-pulse TMS. A large stimulus artefact resulted in MEP responses that could not be assessed in four participants. The assessment of the SMC using sEMG following TMS was poorly reliable for ≈50% of participants. Although using sEMG to assess swallowing musculature function is easier to perform clinically and more comfortable to patients than invasive measures, as the measurement of muscle activity using TMS is unreliable, the use of sEMG for this muscle group is not recommended and requires further research and development. © 2017 John Wiley & Sons Ltd.

  15. 75 FR 67960 - Notice of Availability of Draft National Pollutant Discharge Elimination System (NPDES) General...

    Science.gov (United States)

    2010-11-04

    ... military bases, large hospital or prison complexes, and highways or other thoroughfares. The term does not... as an iterative process. MEP should continually adapt to current conditions and BMP effectiveness... permit requirements, implementing the program, evaluating the effectiveness of the BMPs included as...

  16. Analysis of Potential Energy Saving and CO2 Emission Reduction of Home Appliances and Commercial Equipments in China

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Nan; Fridley, David; McNeil, Michael; Zheng, Nina; Letschert, Virginie; Ke, Jing

    2011-04-01

    China has implemented a series of minimum energy performance standards (MEPS) for over 30 appliances, voluntary energy efficiency label for 40 products and a mandatory energy information label that covers 19 products to date. However, the impact of these programs and their savings potential has not been evaluated on a consistent basis. This paper uses modeling to estimate the energy saving and CO{sub 2} emission reduction potential of the appliances standard and labeling program for products for which standards are currently in place, under development or those proposed for development in 2010 under three scenarios that differ in the pace and stringency of MEPS development. In addition to a baseline 'Frozen Efficiency' scenario at 2009 MEPS level, the 'Continued Improvement Scenario' (CIS) reflects the likely pace of post-2009 MEPS revisions, and the likely improvement at each revision step. The 'Best Practice Scenario' (BPS) examined the potential of an achievement of international best practice efficiency in broad commercial use today in 2014. This paper concludes that under 'CIS', cumulative electricity consumption could be reduced by 9503 TWh, and annual CO{sub 2} emissions of energy used for all 37 products would be 16% lower than in the frozen efficiency scenario. Under a 'BPS' scenario for a subset of products, cumulative electricity savings would be 5450 TWh and annual CO{sub 2} emissions reduction of energy used for 11 appliances would be 35% lower.

  17. Maximum entropy production and plant optimization theories.

    Science.gov (United States)

    Dewar, Roderick C

    2010-05-12

    Plant ecologists have proposed a variety of optimization theories to explain the adaptive behaviour and evolution of plants from the perspective of natural selection ('survival of the fittest'). Optimization theories identify some objective function--such as shoot or canopy photosynthesis, or growth rate--which is maximized with respect to one or more plant functional traits. However, the link between these objective functions and individual plant fitness is seldom quantified and there remains some uncertainty about the most appropriate choice of objective function to use. Here, plants are viewed from an alternative thermodynamic perspective, as members of a wider class of non-equilibrium systems for which maximum entropy production (MEP) has been proposed as a common theoretical principle. I show how MEP unifies different plant optimization theories that have been proposed previously on the basis of ad hoc measures of individual fitness--the different objective functions of these theories emerge as examples of entropy production on different spatio-temporal scales. The proposed statistical explanation of MEP, that states of MEP are by far the most probable ones, suggests a new and extended paradigm for biological evolution--'survival of the likeliest'--which applies from biomacromolecules to ecosystems, not just to individuals.

  18. Maximum entropy production in environmental and ecological systems.

    Science.gov (United States)

    Kleidon, Axel; Malhi, Yadvinder; Cox, Peter M

    2010-05-12

    The coupled biosphere-atmosphere system entails a vast range of processes at different scales, from ecosystem exchange fluxes of energy, water and carbon to the processes that drive global biogeochemical cycles, atmospheric composition and, ultimately, the planetary energy balance. These processes are generally complex with numerous interactions and feedbacks, and they are irreversible in their nature, thereby producing entropy. The proposed principle of maximum entropy production (MEP), based on statistical mechanics and information theory, states that thermodynamic processes far from thermodynamic equilibrium will adapt to steady states at which they dissipate energy and produce entropy at the maximum possible rate. This issue focuses on the latest development of applications of MEP to the biosphere-atmosphere system including aspects of the atmospheric circulation, the role of clouds, hydrology, vegetation effects, ecosystem exchange of energy and mass, biogeochemical interactions and the Gaia hypothesis. The examples shown in this special issue demonstrate the potential of MEP to contribute to improved understanding and modelling of the biosphere and the wider Earth system, and also explore limitations and constraints to the application of the MEP principle.

  19. Alternative Methods for Defining Osteoarthritis and the Impact on Estimating Prevalence in a US Population-Based Survey

    Science.gov (United States)

    Cisternas, Miriam G.; Murphy, Louise; Sacks, Jeffrey J.; Solomon, Daniel H.; Pasta, David J.; Helmick, Charles G.

    2015-01-01

    Objective Provide a contemporary estimate of osteoarthritis (OA) by comparing accuracy and prevalence of alternative definitions of OA. Methods The Medical Expenditure Panel Survey (MEPS) household component (HC) records respondent-reported medical conditions as open-ended responses; professional coders translate these responses into ICD-9-CM codes for the medical conditions files. Using these codes and other data from the MEPS-HC medical conditions files, we constructed three case definitions of OA and assessed them against medical provider diagnoses of ICD-9-CM 715 [osteoarthrosis and allied disorders] in a MEPS subsample. The three definitions were: 1) strict = ICD-9-CM 715; 2) expanded = ICD-9-CM 715, 716 [other and unspecified arthropathies], OR 719 [other and unspecified disorders of joint]); and 3) probable = strict OR expanded + respondent-reported prior diagnosis of OA or other arthritis excluding rheumatoid arthritis (RA). Results Sensitivity and specificity of the three definitions were: strict – 34.6% and 97.5%; expanded – 73.8% and 90.5%; and probable – 62.9% and 93.5%. Conclusion The strict definition for OA (ICD-9-CM 715) excludes many individuals with OA. The probable definition of OA has the optimal combination of sensitivity and specificity relative to the two other MEPS-based definitions and yields a national annual estimate of 30.8 million adults with OA (13.4% of US adult population) for 2008 – 2011. PMID:26315529

  20. Identification of the pyramidal tract by neuronavigation based on intraoperative magnetic resonance tractography: correlation with subcortical stimulation

    Energy Technology Data Exchange (ETDEWEB)

    Bozzao, Alessandro; Romano, Andrea; Calabria, Luigi Fausto; Coppola, Valeria; Fantozzi, Luigi Maria [University of Rome Sapienza, Department of Neuroradiology, Rome (Italy); Angelini, Albina; D' Andrea, Giancarlo; Mastronardi, Luciano; Ferrante, Luigi [University of Rome Sapienza, Department of Neurosurgery, Rome (Italy)

    2010-10-15

    To demonstrate the accuracy of magnetic resonance tractography (MRT) in localizing the cortical spinal tract (CST) close to brain tumours by using intraoperative electric subcortical stimulation. Nine patients with intra-axial brain tumours underwent neurosurgery. Planning was based on analysis of the course of streamlines compatible with the CST. After tumour removal, intraoperative MRT was reacquired. Sites at various distance from the CST were repeatedly stimulated to assess whether registered motor evoked potential (MEP) could be elicited. All patients were assessed clinically both pre- and postoperatively. The motor function was preserved in all patients. In all patients intraoperative MRT demonstrated shift of the bundle position caused by the surgical procedure. The distance between the estimated intraoperative CST and the point of elicited MEP was 1 cm or less in all nine patients. At distances greater than 2 cm, no patient reported positive MEP. Intraoperative MRT is a reliable technique for localization of CST. In all patients MEP were elicited by direct subcortical electrical stimulation at a distance below 1 cm from the CST as represented by MRT. Brain shifting might impact this evaluation since CST position may change during surgery in the range of 8 mm. (orig.)