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Sample records for acc synthase acs

  1. A type III ACC synthase, ACS7, is involved in root gravitropism in Arabidopsis thaliana

    PubMed Central

    Chang, Ing-Feng

    2013-01-01

    Ethylene is an important plant hormone that regulates developmental processes in plants. The ethylene biosynthesis pathway is a highly regulated process at both the transcriptional and post-translational level. The transcriptional regulation of these ethylene biosynthesis genes is well known. However, post-translational modifications of the key ethylene biosynthesis enzyme 1-aminocyclopropane-1-carboxylate (ACC) synthase (ACS) are little understood. In vitro kinase assays were conducted on the type III ACS, AtACS7, fusion protein and peptides to determine whether the AtACS7 protein can be phosphorylated by calcium-dependent protein kinase (CDPK). AtACS7 was phosphorylated at Ser216, Thr296, and Ser299 by AtCDPK16 in vitro. To investigate further the function of the ACS7 gene in Arabidopsis, an acs7-1 loss-of-function mutant was isolated. The acs7-1 mutant exhibited less sensitivity to the inhibition of root gravitropism by treatment with the calcium chelator ethylene glycol tetraacetic acid (EGTA). Seedlings were treated with gradient concentrations of ACC. The results showed that a certain concentration of ethylene enhanced the gravity response. Moreover, the acs7-1 mutant was less sensitive to inhibition of the gravity response by treatment with the auxin polar transport inhibitor 1-naphthylphthalamic acid, but exogenous ACC application recovered root gravitropism. Altogether, the results indicate that AtACS7 is involved in root gravitropism in a calcium-dependent manner in Arabidopsis. PMID:23943848

  2. C-terminal phosphorylation is essential for regulation of ethylene synthesizing ACC synthase enzyme.

    PubMed

    Choudhury, Swarup Roy; Roy, Sujit; Sengupta, Dibyendu N

    2013-02-01

    The genetic and molecular biological studies mainly in Arabidopsis and in some other plants have begun to uncover the various components of ripening signaling pathway in plants. Although transcriptional regulation of major ripening genes have been studied in detail, information on role of phosphorylation in regulating the activity and stability of core ripening pathway associated proteins in relation to ethylene biosynthesis during fruit ripening is still limited. Recently we have demonstrated the evidence for post-translational regulation of MA-ACS1 (Musa acuminata ACC synthase 1), the rate limiting step enzyme regulating ripening ethylene production in banana, through phosphorylation at the C-terminal Ser 476 and 479 residues by a 41-kDa Ser/Thr protein kinase. (1) Here we have further discussed role of protein phosphorylation in regulation of stability and activity of ACS enzymes and the mechanistic and evolutionary perspective of phosphorylation pattern of Type I ACC synthase enzymes. PMID:23221778

  3. Heterologous over-expression of ACC SYNTHASE8 (ACS8) in Populus tremula x P. alba clone 717-1B4 results in elevated levels of ethylene and induces stem dwarfism and reduced leaf size through separate genetic pathways.

    PubMed

    Plett, Jonathan M; Williams, Martin; LeClair, Gaetan; Regan, Sharon; Beardmore, Tannis

    2014-01-01

    Plant height is an important agronomic and horticultural trait that impacts plant productivity, durability and esthetic appeal. A number of the plant hormones such as gibberellic acid (GA), auxin and ethylene have been linked to control of plant architecture and size. Reduction in GA synthesis and auxin transport result in dwarfism while ethylene may have a permissive or repressive effect on tissue growth depending upon the age of plant tissues or the environmental conditions considered. We describe here an activation-tagged mutant of Populus tremula x P. alba clone 717-1B4 identified from 2000 independent transgenic lines due to its significantly reduced growth rate and smaller leaf size. Named dwarfy, the phenotype is due to increased expression of PtaACC SYNTHASE8, which codes for an enzyme in the first committed step in the biosynthesis of ethylene. Stems of dwarfy contain fiber and vessel elements that are reduced in length while leaves contain fewer cells. These morphological differences are linked to PtaACS8 inducing different transcriptomic programs in the stem and leaf, with genes related to auxin diffusion and sensing being repressed in the stem and genes related to cell division found to be repressed in the leaves. Altogether, our study gives mechanistic insight into the genetics underpinning ethylene-induced dwarfism in a perennial model organism. PMID:25414707

  4. Heterologous over-expression of ACC SYNTHASE8 (ACS8) in Populus tremula x P. alba clone 717-1B4 results in elevated levels of ethylene and induces stem dwarfism and reduced leaf size through separate genetic pathways

    PubMed Central

    Plett, Jonathan M.; Williams, Martin; LeClair, Gaetan; Regan, Sharon; Beardmore, Tannis

    2014-01-01

    Plant height is an important agronomic and horticultural trait that impacts plant productivity, durability and esthetic appeal. A number of the plant hormones such as gibberellic acid (GA), auxin and ethylene have been linked to control of plant architecture and size. Reduction in GA synthesis and auxin transport result in dwarfism while ethylene may have a permissive or repressive effect on tissue growth depending upon the age of plant tissues or the environmental conditions considered. We describe here an activation-tagged mutant of Populus tremula x P. alba clone 717-1B4 identified from 2000 independent transgenic lines due to its significantly reduced growth rate and smaller leaf size. Named dwarfy, the phenotype is due to increased expression of PtaACC SYNTHASE8, which codes for an enzyme in the first committed step in the biosynthesis of ethylene. Stems of dwarfy contain fiber and vessel elements that are reduced in length while leaves contain fewer cells. These morphological differences are linked to PtaACS8 inducing different transcriptomic programs in the stem and leaf, with genes related to auxin diffusion and sensing being repressed in the stem and genes related to cell division found to be repressed in the leaves. Altogether, our study gives mechanistic insight into the genetics underpinning ethylene-induced dwarfism in a perennial model organism. PMID:25414707

  5. Ozone stress induces the expression of ACC synthase in potato plants

    SciTech Connect

    Schlagnhaufer, C.D.; Arteca, R.N.; Pell, E.J. )

    1993-05-01

    When potato plants (Solanum tuberosum L. cv Norland) are subjected to oxone stress ethylene is emitted. Increases in ethylene production are often the result of increased expression of the enzyme ACC synthase. We used the polymerase chain reaction (PCR) to clone a cDNA encoding an ozone-induced ACC synthase. After treating potato plants with 300 ppb ozone for 4 h, RNA was extracted using a guanidinium isothiocyanate method. Using degenerate oligonucleotides corresponding to several conserved regions of ACC synthase sequences reported from different plant tissues as primers, we were able to reverse transcribe the RNA and amplify a cDNA for ACC synthase. The clone is 1098 bp in length encoding for 386 amino acids comprising [approximately]80% of the protein. Computer analysis of the deduced amino acid sequence showed that our clone is 50-70% homologous with ACC synthase genes cloned from other plant tissues. Using the cDNA as a probe in northern analysis we found that there is little or no expression in control tissue: however there is a large increase in the expression of the ACC synthase message in response to ozone treatment.

  6. ACCE/ACS National Educator and Leader of the Year Winners: AEC Congratulates These Outstanding Educators

    ERIC Educational Resources Information Center

    Australian Educational Computing, 2012

    2012-01-01

    This article presents the ACCE/ACS National Educator and Leader of the Year winners. Anne Mirtschin is the recipient of the ACCE/ACS 2012 Educator of the Year Award. Mirtschin is an innovative teacher at Hawkesdale P-12 College a small rural school that is isolated culturally and geographically. She uses online tools and technology to create…

  7. Differential regulation of genes encoding 1-aminocyclopropane-1-carboxylate (ACC) synthase in etiolated pea seedlings: effects of indole-3-acetic acid, wounding, and ethylene.

    PubMed

    Peck, S C; Kende, H

    1998-12-01

    Treatment of 5- to 6-day-old etiolated pea (Pisum sativum L.) seedlings with indole-3-acetic acid (IAA) induced within 15 min an increase in the transcript levels of two genes encoding 1-aminocyclopropane-1-carboxylate (ACC) synthase, Ps-ACS1 and Ps-ACS2. Simultaneous treatment with ethylene inhibited this increase and also caused a decrease in ACC synthase enzyme activity as compared to that of seedlings treated with IAA alone. These results indicate that ethylene inhibits its own biosynthesis by decreasing ACC synthase transcript levels via a negative feedback loop. Wounding of pea stems had no effect on the expression of Ps-ACS1, but led within 10 min to an increase in the mRNA levels of Ps-ACS2. This increase was also inhibited by ethylene. The wound signal was transmitted over a distance of at least 4 cm through the stem with no delay in induction or response intensity. The rapid transmission of the wound response is consistent with the possibility that a hydraulic or electric signal is responsible for the spread of the wound response. PMID:9869404

  8. Expression characteristics of CS-ACS1, CS-ACS2 and CS-ACS3, three members of the 1-aminocyclopropane-1-carboxylate synthase gene family in cucumber (Cucumis sativus L.) fruit under carbon dioxide stress.

    PubMed

    Mathooko, F M; Mwaniki, M W; Nakatsuka, A; Shiomi, S; Kubo, Y; Inaba, A; Nakamura, R

    1999-02-01

    We investigated the expression pattern of three 1-aminocyclopropane-1-carboxylate (ACC) synthase genes, CS-ACS1, CS-ACS2 and CS-ACS3 in cucumber (Cucumis sativus L.) fruit under CO2 stress. CO2 stress-induced ethylene production paralleled the accumulation of only CS-ACS1 transcripts which disappeared upon withdrawal of CO2. Cycloheximide inhibited the CO2 stress-induced ethylene production but superinduced the accumulation of CS-ACS1 transcript. At higher concentrations, cycloheximide also induced the accumulation of CS-ACS2 and CS-ACS3 transcripts. In the presence of CO2 and cycloheximide, the accumulation of CS-ACS2 transcript occurred within 1 h, disappeared after 3 h and increased greatly upon withdrawal of CO2. Inhibitors of protein kinase and types 1 and 2A protein phosphatases which inhibited and stimulated, respectively, CO2 stress-induced ethylene production had little effect on the expression of these genes. The results presented here identify CS-ACS1 as the main ACC synthase gene responsible for the increased ethylene biosynthesis in cucumber fruit under CO2 stress and suggest that this gene is a primary response gene and its expression is under negative control since it is expressed by treatment with cycloheximide. The results further suggest that the regulation of CO2 stress-induced ethylene biosynthesis by reversible protein phosphorylation does not result from enhanced ACC synthase transcription. PMID:10202812

  9. The promoter of LE-ACS7, an early flooding-induced 1-aminocyclopropane-1-carboxylate synthase gene of the tomato, is tagged by a Sol3 transposon

    PubMed Central

    Shiu, Oi Yin; Oetiker, Jürg H.; Yip, Wing Kin; Yang, Shang Fa

    1998-01-01

    Many terrestrial plants respond to flooding with enhanced ethylene production. The roots of flooded plants produce 1-aminocyclopropane-1-carboxylic acid (ACC), which is transported from the root to the shoot, where it is converted to ethylene. In the roots, ACC is synthesized by ACC synthase, which is encoded by a multigene family. Previously, we identified two ACC synthase genes of tomato that are involved in flooding-induced ethylene production. Here, we report the cloning of LE-ACS7, a new tomato ACC synthase with a role early during flooding but also in the early wound response of leaves. The promoter of LE-ACS7 is tagged by a Sol3 transposon. A Sol3 transposon is also present in the tomato polygalacturonase promoter to which it conferred regulatory elements. Thus, Sol3 transposons may affect the regulation of LE-ACS7 and may be involved in the communication between the root and the shoot of waterlogged tomato plants. PMID:9707648

  10. The formation of ACC and competition between polyamines and ethylene for SAM

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ethylene biosynthesis involves the conversion of S-adenosylmethionine (SAM) to 1-aminocyclopropane-1-carboxylic acid (ACC) by ACC synthase (ACS). ACC is then converted to ethylene. The genes that encode enzymes in this pathway all belong to a family of genes. Differential transcriptional regulation ...

  11. ACLY and ACC1 Regulate Hypoxia-Induced Apoptosis by Modulating ETV4 via α-ketoglutarate

    PubMed Central

    Keenan, Melissa M.; Liu, Beiyu; Tang, Xiaohu; Wu, Jianli; Cyr, Derek; Stevens, Robert D.; Ilkayeva, Olga; Huang, Zhiqing; Tollini, Laura A.; Murphy, Susan K.; Lucas, Joseph; Muoio, Deborah M.; Kim, So Young; Chi, Jen-Tsan

    2015-01-01

    In order to propagate a solid tumor, cancer cells must adapt to and survive under various tumor microenvironment (TME) stresses, such as hypoxia or lactic acidosis. To systematically identify genes that modulate cancer cell survival under stresses, we performed genome-wide shRNA screens under hypoxia or lactic acidosis. We discovered that genetic depletion of acetyl-CoA carboxylase (ACACA or ACC1) or ATP citrate lyase (ACLY) protected cancer cells from hypoxia-induced apoptosis. Additionally, the loss of ACLY or ACC1 reduced levels and activities of the oncogenic transcription factor ETV4. Silencing ETV4 also protected cells from hypoxia-induced apoptosis and led to remarkably similar transcriptional responses as with silenced ACLY or ACC1, including an anti-apoptotic program. Metabolomic analysis found that while α-ketoglutarate levels decrease under hypoxia in control cells, α-ketoglutarate is paradoxically increased under hypoxia when ACC1 or ACLY are depleted. Supplementation with α-ketoglutarate rescued the hypoxia-induced apoptosis and recapitulated the decreased expression and activity of ETV4, likely via an epigenetic mechanism. Therefore, ACC1 and ACLY regulate the levels of ETV4 under hypoxia via increased α-ketoglutarate. These results reveal that the ACC1/ACLY-α-ketoglutarate-ETV4 axis is a novel means by which metabolic states regulate transcriptional output for life vs. death decisions under hypoxia. Since many lipogenic inhibitors are under investigation as cancer therapeutics, our findings suggest that the use of these inhibitors will need to be carefully considered with respect to oncogenic drivers, tumor hypoxia, progression and dormancy. More broadly, our screen provides a framework for studying additional tumor cell stress-adaption mechanisms in the future. PMID:26452058

  12. AcsA-AcsB: The core of the cellulose synthase complex from Gluconacetobacter hansenii ATCC23769.

    PubMed

    McManus, John B; Deng, Ying; Nagachar, Nivedita; Kao, Teh-hui; Tien, Ming

    2016-01-01

    The gram-negative bacterium, Gluconacetobacter hansenii, produces cellulose of exceptionally high crystallinity in comparison to the cellulose of higher plants. This bacterial cellulose is synthesized and extruded into the extracellular medium by the cellulose synthase complex (CSC). The catalytic component of this complex is encoded by the gene AcsAB. However, several other genes are known to encode proteins critical to cellulose synthesis and are likely components of the bacterial CSC. We have purified an active heterodimer AcsA-AcsB from G. hansenii ATCC23769 to homogeneity by two different methods. With the purified protein, we have determined how it is post-translationally processed, forming the active heterodimer AcsA-AcsB. Additionally, we have performed steady-state kinetic studies on the AcsA-AcsB complex. Finally through mutagenesis studies, we have explored the roles of the postulated CSC proteins AcsC, AcsD, and CcpAx. PMID:26672449

  13. Identification of a second cellulose synthase gene (acsAII) in Acetobacter xylinum.

    PubMed Central

    Saxena, I M; Brown, R M

    1995-01-01

    A second cellulose synthase gene (acsAII) coding for a 175-kDa polypeptide that is similar in size and sequence to the acsAB gene product has been identified in Acetobacter xylinum AY201. Evidence for the presence of this gene was obtained during analysis of A. xylinum mutants in which the acsAB gene was disrupted (I.M. Saxena, K. Kudlicka, K. Okuda, and R.M. Brown, Jr., J. Bacteriol. 176:5735-5752, 1994). Although these mutants produced no detectable cellulose, they exhibited significant cellulose synthase activity in vitro. The acsAII gene was isolated by using an acsAB gene fragment as a probe. The acsAII gene coded for cellulose synthase activity as determined from sequence analysis and study of mutants in which this gene was disrupted. A mutant in which only the acsAII gene was disrupted showed no significant differences in either the in vivo cellulose production or the in vitro cellulose synthase activity compared with wild-type cells. Mutants in which both the acsAII and acsAB genes were disrupted produced no cellulose in vivo and exhibited negligible cellulose synthase activity in vitro, thus confirming that the cellulose synthase activity observed in the acsAB mutants was coded by the acsAII gene. These results establish the presence of an additional gene for cellulose synthase expressed in cells of A. xylinum, yet this gene is not required for cellulose production when cells are grown under laboratory conditions. PMID:7665515

  14. Three 1-Aminocyclopropane-1-Carboxylate Synthase Genes Regulated by Primary and Secondary Pollination Signals in Orchid Flowers1

    PubMed Central

    Bui, Anhthu Q.; Neill, Sharman D. O'

    1998-01-01

    The temporal and spatial expression patterns of three 1-aminocyclopropane-1-carboxylate (ACC) synthase genes were investigated in pollinated orchid (Phalaenopsis spp.) flowers. Pollination signals initiate a cascade of development events in multiple floral organs, including the induction of ethylene biosynthesis, which coordinates several postpollination developmental responses. The initiation and propagation of ethylene biosynthesis is regulated by the coordinated expression of three distinct ACC synthase genes in orchid flowers. One ACC synthase gene (Phal-ACS1) is regulated by ethylene and participates in amplification and interorgan transmission of the pollination signal, as we have previously described in a related orchid genus. Two additional ACC synthase genes (Phal-ACS2 and Phal-ACS3) are expressed primarily in the stigma and ovary of pollinated orchid flowers. Phal-ACS2 mRNA accumulated in the stigma within 1 h after pollination, whereas Phal-ACS1 mRNA was not detected until 6 h after pollination. Similar to the expression of Phal-ACS2, the Phal-ACS3 gene was expressed within 2 h after pollination in the ovary. Exogenous application of auxin, but not ACC, mimicked pollination by stimulating a rapid increase in ACC synthase activity in the stigma and ovary and inducing Phal-ACS2 and Phal-ACS3 mRNA accumulation in the stigma and ovary, respectively. These results provide the basis for an expanded model of interorgan regulation of three ACC synthase genes that respond to both primary (Phal-ACS2 and Phal-ACS3) and secondary (Phal-ACS1) pollination signals. PMID:9449850

  15. Three 1-aminocyclopropane-1-carboxylate synthase genes regulated by primary and secondary pollination signals in orchid flowers.

    PubMed

    Bui, A Q; O'Neill, S D

    1998-01-01

    The temporal and spatial expression patterns of three 1-aminocyclopropane-1-carboxylate (ACC) synthase genes were investigated in pollinated orchid (Phalaenopsis spp.) flowers. Pollination signals initiate a cascade of development events in multiple floral organs, including the induction of ethylene biosynthesis, which coordinates several postpollination developmental responses. The initiation and propagation of ethylene biosynthesis is regulated by the coordinated expression of three distinct ACC synthase genes in orchid flowers. One ACC synthase gene (Phal-ACS1) is regulated by ethylene and participates in amplification and interorgan transmission of the pollination signal, as we have previously described in a related orchid genus. Two additional ACC synthase genes (Phal-ACS2 and Phal-ACS3) are expressed primarily in the stigma and ovary of pollinated orchid flowers. Phal-ACS2 mRNA accumulated in the stigma within 1 h after pollination, whereas Phal-ACS1 mRNA was not detected until 6 h after pollination. Similar to the expression of Phal-ACS2, the Phal-ACS3 gene was expressed within 2 h after pollination in the ovary. Exogenous application of auxin, but not ACC, mimicked pollination by stimulating a rapid increase in ACC synthase activity in the stigma and ovary and inducing Phal-ACS2 and Phal-ACS3 mRNA accumulation in the stigma and ovary, respectively. These results provide the basis for an expanded model of interorgan regulation of three ACC synthase genes that respond to both primary (Phal-ACS2 and Phal-ACS3) and secondary (Phal-ACS1) pollination signals. PMID:9449850

  16. Arabidopsis protein phosphatase 2C ABI1 interacts with type I ACC synthases and is involved in the regulation of ozone-induced ethylene biosynthesis.

    PubMed

    Ludwików, Agnieszka; Cieśla, Agata; Kasprowicz-Maluśki, Anna; Mituła, Filip; Tajdel, Małgorzata; Gałgański, Łukasz; Ziółkowski, Piotr A; Kubiak, Piotr; Małecka, Arleta; Piechalak, Aneta; Szabat, Marta; Górska, Alicja; Dąbrowski, Maciej; Ibragimow, Izabela; Sadowski, Jan

    2014-06-01

    Ethylene plays a crucial role in various biological processes and therefore its biosynthesis is strictly regulated by multiple mechanisms. Posttranslational regulation, which is pivotal in controlling ethylene biosynthesis, impacts 1-aminocyclopropane 1-carboxylate synthase (ACS) protein stability via the complex interplay of specific factors. Here, we show that the Arabidopsis thaliana protein phosphatase type 2C, ABI1, a negative regulator of abscisic acid signaling, is involved in the regulation of ethylene biosynthesis under oxidative stress conditions. We found that ABI1 interacts with ACS6 and dephosphorylates its C-terminal fragment, a target of the stress-responsive mitogen-activated protein kinase, MPK6. In addition, ABI1 controls MPK6 activity directly and by this means also affects the ACS6 phosphorylation level. Consistently with this, ozone-induced ethylene production was significantly higher in an ABI1 knockout strain (abi1td) than in wild-type plants. Importantly, an increase in stress-induced ethylene production in the abi1td mutant was compensated by a higher ascorbate redox state and elevated antioxidant activities. Overall, the results of this study provide evidence that ABI1 restricts ethylene synthesis by affecting the activity of ACS6. The ABI1 contribution to stress phenotype underpins its role in the interplay between the abscisic acid (ABA) and ethylene signaling pathways. PMID:24637173

  17. Management of Patients With NSTE-ACS: A Comparison of the Recent AHA/ACC and ESC Guidelines.

    PubMed

    Rodriguez, Fatima; Mahaffey, Kenneth W

    2016-07-19

    Non-ST-segment elevation acute coronary syndromes (NSTE-ACS) are the leading cause of morbidity and mortality from cardiovascular disease worldwide. The American Heart Association/American College of Cardiology and the European Society of Cardiology periodically release practice guidelines to guide clinicians in the management of NSTE-ACS, most recently in in 2014 and 2015, respectively. The present review compares and contrasts the 2 guidelines, with a focus on the strength of recommendation and level of evidence in the approach to initial presentation and diagnosis of NSTE-ACS, risk assessment, treatments, and systems of care. Important differences include the use of a rapid rule-out protocol with high-sensitivity troponin assays, a preference for prasugrel/ticagrelor and fondaparinux for anticoagulation therapy, and a preference for radial arterial access in the European Society of Cardiology guidelines compared with the American Heart Association/American College of Cardiology guidelines. We also highlight the similarities and differences in the guidelines for special patient populations and suggest areas of further study. PMID:27417010

  18. 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.

    PubMed

    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. PMID:20689184

  19. Synthesis and biological evaluation of several dephosphonated analogues of CMP-Neu5Ac as inhibitors of GM3-synthase.

    PubMed

    Rota, Paola; Cirillo, Federica; Piccoli, Marco; Gregorio, Antonio; Tettamanti, Guido; Allevi, Pietro; Anastasia, Luigi

    2015-10-01

    Previous studies demonstrated that reducing the GM3 content in myoblasts increased the cell resistance to hypoxic stress, suggesting that a pharmacological inhibition of the GM3 synthesis could be instrumental for the development of new treatments for ischemic diseases. Herein, the synthesis of several dephosphonated CMP-Neu5Ac congeners and their anti-GM3-synthase activity is reported. Biological activity testes revealed that some inhibitors almost completely blocked the GM3-synthase activity in vitro and reduced the GM3 content in living embryonic kidney 293A cells, eventually activating the epidermal growth factor receptor (EGFR) signaling cascade. PMID:26397189

  20. Mutation in the gene encoding 1-aminocyclopropane-1-carboxylate synthase 4 (CitACS4) led to andromonoecy in watermelon.

    PubMed

    Ji, Gaojie; Zhang, Jie; Zhang, Haiying; Sun, Honghe; Gong, Guoyi; Shi, Jianting; Tian, Shouwei; Guo, Shaogui; Ren, Yi; Shen, Huolin; Gao, Junping; Xu, Yong

    2016-09-01

    Although it has been reported previously that ethylene plays a critical role in sex determination in cucurbit species, how the andromonoecy that carries both the male and hermaphroditic flowers is determined in watermelon is still unknown. Here we showed that the watermelon gene 1-aminocyclopropane-1-carboxylate synthase 4 (CitACS4), expressed specifically in carpel primordia, determines the andromonoecy in watermelon. Among four single nucleotide polymorphism (SNPs) and one InDel identified in the coding region of CitACS4, the C364W mutation located in the conserved box 6 was co-segregated with andromonoecy. Enzymatic analyses showed that the C364W mutation caused a reduced activity in CitACS4. We believe that the reduced CitACS4 activity may hamper the programmed cell death in stamen primordia, leading to the formation of hermaphroditic flowers. PMID:26839981

  1. Adaptive Cruise Control (ACC)

    NASA Astrophysics Data System (ADS)

    Reif, Konrad

    Die adaptive Fahrgeschwindigkeitsregelung (ACC, Adaptive Cruise Control) ist eine Weiterentwicklung der konventionellen Fahrgeschwindigkeitsregelung, die eine konstante Fahrgeschwindigkeit einstellt. ACC überwacht mittels eines Radarsensors den Bereich vor dem Fahrzeug und passt die Geschwindigkeit den Gegebenheiten an. ACC reagiert auf langsamer vorausfahrende oder einscherende Fahrzeuge mit einer Reduzierung der Geschwindigkeit, sodass der vorgeschriebene Mindestabstand zum vorausfahrenden Fahrzeug nicht unterschritten wird. Hierzu greift ACC in Antrieb und Bremse ein. Sobald das vorausfahrende Fahrzeug beschleunigt oder die Spur verlässt, regelt ACC die Geschwindigkeit wieder auf die vorgegebene Sollgeschwindigkeit ein (Bild 1). ACC steht somit für eine Geschwindigkeitsregelung, die sich dem vorausfahrenden Verkehr anpasst.

  2. An ACC Oxidase Gene Essential for Cucumber Carpel Development.

    PubMed

    Chen, Huiming; Sun, Jinjing; Li, Shuai; Cui, Qingzhi; Zhang, Huimin; Xin, Fengjiao; Wang, Huaisong; Lin, Tao; Gao, Dongli; Wang, Shenhao; Li, Xia; Wang, Donghui; Zhang, Zhonghua; Xu, Zhihong; Huang, Sanwen

    2016-09-01

    Sex determination in plants gives rise to unisexual flowers that facilitate outcrossing and enhance genetic diversity. In cucumber and melon, ethylene promotes carpel development and arrests stamen development. Five sex-determination genes have been identified, including four encoding 1-aminocyclopropane-1-carboxylate (ACC) synthase that catalyzes the rate-limiting step in ethylene biosynthesis, and a transcription factor gene CmWIP1 that corresponds to the Mendelian locus gynoecious in melon and is a negative regulator of femaleness. ACC oxidase (ACO) converts ACC into ethylene; however, it remains elusive which ACO gene in the cucumber genome is critical for sex determination and how CmWIP1 represses development of female flowers. In this study, we discovered that mutation in an ACO gene, CsACO2, confers androecy in cucumber that bears only male flowers. The mutation disrupts the enzymatic activity of CsACO2, resulting in 50% less ethylene emission from shoot tips. CsACO2 was expressed in the carpel primordia and its expression overlapped with that of CsACS11 in female flowers at key stages for sex determination, presumably providing sufficient ethylene required for proper CsACS2 expression. CmACO3, the ortholog of CsACO2, showed a similar expression pattern in the carpel region, suggesting a conserved function of CsACO2/CmACO3. We demonstrated that CsWIP1, the ortholog of CmWIP1, could directly bind the promoter of CsACO2 and repress its expression. Taken together, we propose a presumably conserved regulatory module consisting of WIP1 transcription factor and ACO controls unisexual flower development in cucumber and melon. PMID:27403533

  3. Identification of a 1-aminocyclopropane-1-carboxylic acid synthase gene linked to the female (F) locus that enhances female sex expression in cucumber.

    PubMed Central

    Trebitsh, T; Staub, J E; O'Neill, S D

    1997-01-01

    Sex determination in cucumber (Cucumis sativus L.) is controlled largely by three genes: F, m, and a. The F and m loci interact to produce monoecious (M_f_) or gynoecious (M_f_) sex phenotypes. Ethylene and factors that induce ethylene biosynthesis, such as 1-aminocyclopropane-1-carboxylate (ACC) and auxin, also enhance female sex expression. A genomic sequence (CS-ACS1) encoding ACC synthase was amplified from genomic DNA by a polymerase chain reaction using degenerate oligonucleotide primers. Expression of CS-ACS1 is induced by auxin, but not by ACC, in wounded and intact shoot apices. Southern blo hybridization analysis of near-isogenic gynoecious (MMFF) and monoecious (MMff) lines derived from divers genetic backgrounds revealed the existence of an additional ACC synthase (CS-ACS1G) genomic sequence in the gynoecious lines. Sex phenotype analysis of a segregating F2 population detected a 100% correlation between the CS-ACS1G marker and the presence of the F locus. The CS-ACS1G gene is located in linkage group B coincident with the F locus, and in the population tested there was no recombination between the CS-ACS1G gene and the F locus. Collectively, these data suggest that CS-ACS1G is closely linked to the F locus and may play a pivotal role in the determination of sex in cucumber flowers. PMID:9085580

  4. AcsF Catalyzes the ATP-dependent Insertion of Nickel into the Ni,Ni-[4Fe4S] Cluster of Acetyl-CoA Synthase.

    PubMed

    Gregg, Christina M; Goetzl, Sebastian; Jeoung, Jae-Hun; Dobbek, Holger

    2016-08-26

    Acetyl-CoA synthase (ACS) catalyzes the reversible condensation of CO, CoA, and a methyl-cation to form acetyl-CoA at a unique Ni,Ni-[4Fe4S] cluster (the A-cluster). However, it was unknown which proteins support the assembly of the A-cluster. We analyzed the product of a gene from the cluster containing the ACS gene, cooC2 from Carboxydothermus hydrogenoformans, named AcsFCh, and showed that it acts as a maturation factor of ACS. AcsFCh and inactive ACS form a stable 2:1 complex that binds two nickel ions with higher affinity than the individual components. The nickel-bound ACS-AcsFCh complex remains inactive until MgATP is added, thereby converting inactive to active ACS. AcsFCh is a MinD-type ATPase and belongs to the CooC protein family, which can be divided into homologous subgroups. We propose that proteins of one subgroup are responsible for assembling the Ni,Ni-[4Fe4S] cluster of ACS, whereas proteins of a second subgroup mature the [Ni4Fe4S] cluster of carbon monoxide dehydrogenases. PMID:27382049

  5. Cadmium-induced ethylene production and responses in Arabidopsis thaliana rely on ACS2 and ACS6 gene expression

    PubMed Central

    2014-01-01

    Background Anthropogenic activities cause metal pollution worldwide. Plants can absorb and accumulate these metals through their root system, inducing stress as a result of excess metal concentrations inside the plant. Ethylene is a regulator of multiple plant processes, and is affected by many biotic and abiotic stresses. Increased ethylene levels have been observed after exposure to excess metals but it remains unclear how the increased ethylene levels are achieved at the molecular level. In this study, the effects of cadmium (Cd) exposure on the production of ethylene and its precursor 1-aminocyclopropane-1-carboxylic acid (ACC), and on the expression of the ACC Synthase (ACS) and ACC Oxidase (ACO) multigene families were investigated in Arabidopsis thaliana. Results Increased ethylene release after Cd exposure was directly measurable in a system using rockwool-cultivated plants; enhanced levels of the ethylene precursor ACC together with higher mRNA levels of ethylene responsive genes: ACO2, ETR2 and ERF1 also indicated increased ethylene production in hydroponic culture. Regarding underlying mechanisms, it was found that the transcript levels of ACO2 and ACO4, the most abundantly expressed members of the ACO multigene family, were increased upon Cd exposure. ACC synthesis is the rate-limiting step in ethylene biosynthesis, and transcript levels of both ACS2 and ACS6 showed the highest increase and became the most abundant isoforms after Cd exposure, suggesting their importance in the Cd-induced increase of ethylene production. Conclusions Cadmium induced the biosynthesis of ACC and ethylene in Arabidopsis thaliana plants mainly via the increased expression of ACS2 and ACS6. This was confirmed in the acs2-1acs6-1 double knockout mutants, which showed a decreased ethylene production, positively affecting leaf biomass and resulting in a delayed induction of ethylene responsive gene expressions without significant differences in Cd contents between wild-type and

  6. A Ser/Thr protein kinase phosphorylates MA-ACS1 (Musa acuminata 1-aminocyclopropane-1-carboxylic acid synthase 1) during banana fruit ripening.

    PubMed

    Choudhury, Swarup Roy; Roy, Sujit; Sengupta, Dibyendu N

    2012-08-01

    1-Aminocyclopropane-1-carboxylic acid synthase (ACS) catalyzes the rate-limiting step in ethylene biosynthesis during ripening. ACS isozymes are regulated both transcriptionally and post-translationally. However, in banana, an important climacteric fruit, little is known about post-translational regulation of ACS. Here, we report the post-translational modification of MA-ACS1 (Musa acuminata ACS1), a ripening inducible isozyme in the ACS family, which plays a key role in ethylene biosynthesis during banana fruit ripening. Immunoprecipitation analyses of phospholabeled protein extracts from banana fruit using affinity-purified anti-MA-ACS1 antibody have revealed phosphorylation of MA-ACS1, particularly in ripe fruit tissue. We have identified the induction of a 41-kDa protein kinase activity in pulp at the onset of ripening. The 41-kDa protein kinase has been identified as a putative protein kinase by MALDI-TOF/MS analysis. Biochemical analyses using partially purified protein kinase fraction from banana fruit have identified the protein kinase as a Ser/Thr family of protein kinase and its possible involvement in MA-ACS1 phosphorylation during ripening. In vitro phosphorylation analyses using synthetic peptides and site-directed mutagenized recombinant MA-ACS1 have revealed that serine 476 and 479 residues at the C-terminal region of MA-ACS1 are phosphorylated. Overall, this study provides important novel evidence for in vivo phosphorylation of MA-ACS1 at the molecular level as a possible mechanism of post-translational regulation of this key regulatory protein in ethylene signaling pathway in banana fruit during ripening. PMID:22419220

  7. Effects of feeding transgenic corn with mCry1Ac or maroACC gene to laying hens for 12 weeks on growth, egg quality and organ health.

    PubMed

    Zhong, R Q; Chen, L; Gao, L X; Zhang, L L; Yao, B; Yang, X G; Zhang, H F

    2016-08-01

    The objective of the present study was to investigate the effect of feeding two transgenic corn lines containing the mCry1Ac gene from Bacillus thuringiensis strain (BT-799) and the maroACC gene from Agrobacterium tumefaciens strain (CC-2), respectively, on growth, egg quality and organ health indicators. Expression of the mCry1Ac gene confers resistance to Pyrausta nubilalis and the maroACC gene confers tolerance to herbicides. Healthy hens (n=96 placed in cages; 3 hens/cage) were randomly assigned to one of four corn-soybean meal dietary treatments (8 cages/treatment) formulated with the following corn: non-transgenic near-isoline control corn (control), BT-799 corn, CC-2 corn and commercially available non-transgenic reference corn (reference). The experiment was divided into three 4-week phases (week 1 to 4, week 5 to 8 and week 9 to 12), during which hens were fed mash diets. Performance (BW, feed intake and egg production) and egg quality were determined. Following slaughter at the end of 12 weeks of feeding (n=8/treatment), carcass yield and organ weights (heart, liver, spleen, lung, kidneys, stomach and ovary) were recorded; organs and intestines were sampled for histological analysis. Analysis of serum biochemistry parameters to assess the liver and kidney function were performed. No differences in BW, egg production and production efficiency were observed between hens consuming the control diet and hens consuming the BT-799 or CC-2 diet. Haugh unit measures and egg component weights were similar between the control and test groups. Carcass yield was not affected by the diet treatment. Similar organosomatic indices and serum parameters did not indicate the characteristics of organ dysfunction. All observed values of the BT-799 and CC-2 groups were within the calculated tolerance intervals. This research indicates that the performance, egg quality, organ health and carcass yield of laying hens fed diets containing the BT-799 or CC-2 corn line were similar

  8. Assessing the allelotypic effect of two aminocyclopropane carboxylic acid synthase-encoding genes MdACS1 and MdACS3a on fruit ethylene production and softening in Malus

    PubMed Central

    Dougherty, Laura; Zhu, Yuandi; Xu, Kenong

    2016-01-01

    Phytohormone ethylene largely determines apple fruit shelf life and storability. Previous studies demonstrated that MdACS1 and MdACS3a, which encode 1-aminocyclopropane-1-carboxylic acid synthases (ACS), are crucial in apple fruit ethylene production. MdACS1 is well-known to be intimately involved in the climacteric ethylene burst in fruit ripening, while MdACS3a has been regarded a main regulator for ethylene production transition from system 1 (during fruit development) to system 2 (during fruit ripening). However, MdACS3a was also shown to have limited roles in initiating the ripening process lately. To better assess their roles, fruit ethylene production and softening were evaluated at five time points during a 20-day post-harvest period in 97 Malus accessions and in 34 progeny from 2 controlled crosses. Allelotyping was accomplished using an existing marker (ACS1) for MdACS1 and two markers (CAPS866 and CAPS870) developed here to specifically detect the two null alleles (ACS3a-G289V and Mdacs3a) of MdACS3a. In total, 952 Malus accessions were allelotyped with the three markers. The major findings included: The effect of MdACS1 was significant on fruit ethylene production and softening while that of MdACS3a was less detectable; allele MdACS1–2 was significantly associated with low ethylene and slow softening; under the same background of the MdACS1 allelotypes, null allele Mdacs3a (not ACS3a-G289V) could confer a significant delay of ethylene peak; alleles MdACS1–2 and Mdacs3a (excluding ACS3a-G289V) were highly enriched in M. domestica and M. hybrid when compared with those in M. sieversii. These findings are of practical implications in developing apples of low and delayed ethylene profiles by utilizing the beneficial alleles MdACS1-2 and Mdacs3a. PMID:27231553

  9. Assessing the allelotypic effect of two aminocyclopropane carboxylic acid synthase-encoding genes MdACS1 and MdACS3a on fruit ethylene production and softening in Malus.

    PubMed

    Dougherty, Laura; Zhu, Yuandi; Xu, Kenong

    2016-01-01

    Phytohormone ethylene largely determines apple fruit shelf life and storability. Previous studies demonstrated that MdACS1 and MdACS3a, which encode 1-aminocyclopropane-1-carboxylic acid synthases (ACS), are crucial in apple fruit ethylene production. MdACS1 is well-known to be intimately involved in the climacteric ethylene burst in fruit ripening, while MdACS3a has been regarded a main regulator for ethylene production transition from system 1 (during fruit development) to system 2 (during fruit ripening). However, MdACS3a was also shown to have limited roles in initiating the ripening process lately. To better assess their roles, fruit ethylene production and softening were evaluated at five time points during a 20-day post-harvest period in 97 Malus accessions and in 34 progeny from 2 controlled crosses. Allelotyping was accomplished using an existing marker (ACS1) for MdACS1 and two markers (CAPS866 and CAPS870) developed here to specifically detect the two null alleles (ACS3a-G289V and Mdacs3a) of MdACS3a. In total, 952 Malus accessions were allelotyped with the three markers. The major findings included: The effect of MdACS1 was significant on fruit ethylene production and softening while that of MdACS3a was less detectable; allele MdACS1-2 was significantly associated with low ethylene and slow softening; under the same background of the MdACS1 allelotypes, null allele Mdacs3a (not ACS3a-G289V) could confer a significant delay of ethylene peak; alleles MdACS1-2 and Mdacs3a (excluding ACS3a-G289V) were highly enriched in M. domestica and M. hybrid when compared with those in M. sieversii. These findings are of practical implications in developing apples of low and delayed ethylene profiles by utilizing the beneficial alleles MdACS1-2 and Mdacs3a. PMID:27231553

  10. Identification and preliminary characterization of acsF, a Putative Ni-insertase used in the biosynthesis of acetyl-CoA synthase from Clostridium thermoaceticum

    SciTech Connect

    Huay-Keng Loke; Paul A. Lindahl

    2003-01-01

    OAK-B135 The acsABCDE genes in the Clostridium thermoaceticum genome are used for autotrophic acetyl-CoA synthesis using the Wood/Ljungdahl pathway. A 2.8 kb region between acsC and acsD was cloned and sequenced. Two open reading frames, orf7 ({approx} 1.9 kb) and acsF ({approx} 0.7 kb) were identified. orf7 appears to encode an Fe-S protein, in that it contains 5 conserved cysteine residues, 3 of which are present in a motif (CXXXXXCXXC) commonly used to coordinate Fe-S clusters. However, Orf7 is probably not involved in autotrophic acetyl-CoA synthesis, as homologous genes are present in organisms that do not utilize this pathway and are absent in many that do. In contrast, acsF is probably involved in this pathway. Sequence alignment of AcsF and 11 homologs reveals a number of conserved regions, including a P-loop that binds nucleoside triphosphates and catalyzes their hydrolysis. One homolog is CooC, an ATPase/GTPase that inserts Ni into a precursor form of the C-cluster of the carbon monoxide dehydrogenase (CODH) from Rhodospirillum rubrum. Purified AcsF lacked Ni and Fe, and slowly catalyzed the hydrolysis of ATP. Such similarities to CooC suggest that AcsF may function to insert Ni into a Ni-deficient form of the bifunctional acetyl-CoA synthase/CODH from C. thermoaceticum (ACSCt). However, this could not be established, as expression of acsF did not effect activation of recombinant AcsAB expressed in E. coli. Also, E. coli cells defective in hypB retained the ability to synthesize active recombinant AcsAB. Rather, the concentration of extracellular Ni2+ ions was critical to activation.

  11. ACC Study Guide Series.

    ERIC Educational Resources Information Center

    Austin Community Coll., TX. Rio Grande Campus.

    Ten one-page instructional guides designed to assist Austin Community College (ACC) students in using the library and in writing research papers are presented in this series. The titles of the guides are: (1) "The Media Collection (We have more than books in the LRC)"; (2) "Encyclopedias"; (3) "Finding Books"; (4) "Finding a Dictionary or…

  12. Molecular cloning and expression analysis of an 1-aminocyclopropane-1-carboxylate synthase gene from Oncidium Gower Ramsey.

    PubMed

    Shi, Le-Song; Liu, Jin-Ping

    2016-01-01

    1-aminocyclopropane-1-carboxylic acid (ACC) synthase (ACS) is a rate-limiting enzyme in the biosynthesis of ethylene which regulates many aspects of the plant development and responses to biotic and abiotic stresses. In this study, a full-length cDNA of ACC synthase, OnACS2, was cloned from the senescing flower of Oncidium Gower Ramsey by RACE. The full-length cDNA of OnACS2 (GenBank accession no. JQ822087) was 1557 bp in length with an open reading frame (ORF) of 1308 bp encoding for a protein of 435 amino acid residues. The predicted OnACS2 protein had a molecular mass of 49.1 kDa with pI value of 7.51. Phylogenetic analysis indicated its evolutionary relationships with corresponding orthologous sequences in orchids, Hosta ventricosa and monocots. Real-time PCR assay demonstrated that OnACS2 was constitutively expressed in all tested organs with the highest transcript level in the gynandria. Differential expression pattern of OnACS2 gene correlated to the ethylene production and the subsequent occurrence of senescent symptoms in flower suggested that OnACS2 probably played an important role in the initiation of flower senescence. PMID:26631967

  13. The binuclear nickel center in the A-cluster of acetyl-CoA synthase (ACS) and two biomimetic dinickel complexes studied by X-ray absorption and emission spectroscopy

    NASA Astrophysics Data System (ADS)

    Schrapers, P.; Mebs, S.; Ilina, Y.; Warner, D. S.; Wörmann, C.; Schuth, N.; Kositzki, R.; Dau, H.; Limberg, C.; Dobbek, H.; Haumann, M.

    2016-05-01

    Acetyl-CoA synthase (ACS) is involved in the bacterial carbon oxide conversion pathway. The binuclear nickel sites in ACS enzyme and two biomimetic synthetic compounds containing a Ni(II)Ni(II) unit (1 and 2) were compared using XAS/XES. EXAFS analysis of ACS proteins revealed similar Ni-N/O/S bond lengths and Ni-Ni/Fe distances as in the crystal structure in oxidized ACS, but elongated Ni-ligand bonds in reduced ACS, suggesting more reduced nickel species. The XANES spectra of ACS and the dinickel complexes showed overall similar shapes, but less resolved pre-edge and edge features in ACS, attributed to more distorted square-planar nickel sites in particular in reduced ACS. DFT calculation of pre-edge absorption and Kβ2,5 emission features reproduced the experimental spectra of the synthetic complexes, was sensitive even to the small geometry differences in 1 and 2, and indicated low-spin Ni(II) sites. Comparison of nickel sites in proteins and biomimetic compounds is valuable for deducing structural and electronic differences in response to ligation and redox changes.

  14. Evaluating Performance Portability of OpenACC

    SciTech Connect

    Sabne, Amit J; Sakdhnagool, Putt; Lee, Seyong; Vetter, Jeffrey S

    2015-01-01

    Accelerator-based heterogeneous computing is gaining momentum in High Performance Computing arena. However, the increased complexity of the accelerator architectures demands more generic, high-level programming models. OpenACC is one such attempt to tackle the problem. While the abstraction endowed by OpenACC offers productivity, it raises questions on its portability. This paper evaluates the performance portability obtained by OpenACC on twelve OpenACC programs on NVIDIA CUDA, AMD GCN, and Intel MIC architectures. We study the effects of various compiler optimizations and OpenACC program settings on these architectures to provide insights into the achieved performance portability.

  15. Tomato ACS4 is necessary for timely start of and progression through the climacteric phase of fruit ripening

    PubMed Central

    Hoogstrate, Suzanne W.; van Bussel, Lambertus J. A.; Cristescu, Simona M.; Cator, Eric; Mariani, Celestina; Vriezen, Wim H.; Rieu, Ivo

    2014-01-01

    Climacteric fruit ripening, as it occurs in many fruit crops, depends on a rapid, autocatalytic increase in ethylene production. This agriculturally important process has been studied extensively, with tomato simultaneously acting both as a model species and target crop for modification. In tomato, the ethylene biosynthetic genes ACC SYNTHASE2 (ACS2) and ACS4 are highly expressed during fruit ripening, with a combined loss of both ACS2 and ACS4 activity preventing generation of the ethylene burst necessary for fruit ripening. However, the individual roles and importance of ACS2 and ACS4 have not been determined. In this study, we examined specifically the role of ACS4 by comparing the phenotype of an acs4 mutant firstly with that of the wild-type, and secondly with two novel ripening-inhibitor (rin) mutants. Ethylene production during ripening was significantly reduced in both acs4-1, and rin lines, with rin genotypes showing the weaker ethylene burst. Also i) the time between anthesis and the start of fruit ripening and ii) the time required to progress through ripening were significantly longer in acs4-1 than in the wild type, but shorter than in the strongest rin mutant. The delay in ripening was reflected in the lower expression of ripening-related transcripts during the mature green and light red ripening stages. Furthermore, expression of ACS2 and ACS4 was strongly dependent on a functional RIN gene, while ACS2 expression was largely independent of ACS4. Altogether, we show that ACS4 is necessary for normal progression of tomato fruit ripening and that mutation of this gene may provide a useful means for altering ripening traits. PMID:25278945

  16. Airborne Cloud Computing Environment (ACCE)

    NASA Technical Reports Server (NTRS)

    Hardman, Sean; Freeborn, Dana; Crichton, Dan; Law, Emily; Kay-Im, Liz

    2011-01-01

    Airborne Cloud Computing Environment (ACCE) is JPL's internal investment to improve the return on airborne missions. Improve development performance of the data system. Improve return on the captured science data. The investment is to develop a common science data system capability for airborne instruments that encompasses the end-to-end lifecycle covering planning, provisioning of data system capabilities, and support for scientific analysis in order to improve the quality, cost effectiveness, and capabilities to enable new scientific discovery and research in earth observation.

  17. Differential expression of two genes for 1-aminocyclopropane-1-carboxylate synthase in tomato fruits.

    PubMed Central

    Olson, D C; White, J A; Edelman, L; Harkins, R N; Kende, H

    1991-01-01

    1-Aminocyclopropane-1-carboxylate synthase (ACC synthase; S-adenosyl-L-methionine methylthioadenosine-lyase, EC 4.4.1.14) is the regulated enzyme in the biosynthetic pathway of the plant hormone ethylene. A full-length cDNA encoding this enzyme has been cloned from tomato fruits [Van Der Straeten, D., Van Wiemeersch, L., Goodman, H. M. & Van Montagu, M. Proc. Natl. Acad. Sci. USA (1990) 87, 4859-4863]. We report here the complete nucleotide and derived amino acid sequences of a cDNA encoding a second isoform of ACC synthase from tomato fruits. The cDNAs coding for both isoforms contain highly conserved regions that are surrounded by regions of low homology, especially at the 5' and 3' ends. Gene-specific probes were constructed to examine the expression of transcripts encoding the two ACC synthase isoforms under two conditions of enhanced ethylene formation--namely, during fruit ripening and in response to mechanical stress (wounding). The level of mRNA encoding both isoforms, ACC synthase 1 and 2, increased during ripening. In contrast, wounding caused an increase in only the level of mRNA coding for ACC synthase 1. Blot analysis of genomic DNA digested with restriction enzymes confirmed that ACC synthase 1 and 2 are encoded by different genes. Images PMID:1711229

  18. ACC Effectiveness Review, 1999-2002.

    ERIC Educational Resources Information Center

    Wallace, Roslyn, Ed.

    2002-01-01

    These newsletters on Institutional Effectiveness (IE) at Austin Community College (ACC) in Texas include the following articles: (1) "The 'Fast Track'...Students Say It Works!" (2) "Are Students Successfully Completing Distance Learning Courses at ACC?" (3) "Tracking Transfers"; (4) "Math Pilot: Study Skills Attached Labs"; (5)…

  19. Effect of dexamethasone and ACC on bacteria-induced mucin expression in human airway mucosa.

    PubMed

    Hauber, Hans-Peter; Goldmann, Torsten; Vollmer, Ekkehard; Wollenberg, Barbara; Zabel, Peter

    2007-11-01

    Gram-negative bacteria can stimulate mucin production, but excessive mucus supports bacterial infection and consequently leads to airway obstruction. Therefore, the effect of dexamethasone (DEX) and the antioxidant acetyl-cysteine (ACC) on bacteria-induced mucus expression was investigated. Explanted human airway mucosa and mucoepidermoid cells (Calu-3) were stimulated with lipopolysaccharide (LPS) or PAM3 (a synthetic lipoprotein). DEX or ACC were added to either LPS- or PAM3-stimulated airway mucosa or Calu-3 cells. Mucin mRNA expression (MUC5AC) and total mucus glycoconjugates (mucin protein) were quantified using real-time PCR and periodic acid Schiff staining. LPS and PAM3 significantly increased mucin expression in airway mucosa and Calu-3 cells (P < 0.05). DEX alone had no significant effect on mucin expression in airway mucosa or Calu-3 cells (P > 0.05). In contrast, DEX significantly reduced LPS- and PAM3-induced mucin expression in explanted mucosal tissue and mucin expression in Calu-3 cells (P < 0.05). In explanted human airway mucosa ACC alone significantly increased mucin expression (P < 0.05). In contrast, ACC significantly decreased LPS- and PAM3-induced mucin expression (P < 0.05). In Calu-3 cells ACC alone had no significant effect on mucin expression (P > 0.05). ACC decreased LPS- and PAM3-induced mucin expression, but this effect was not significant (P > 0.05). These data suggest that DEX can effectively reduce bacteria-induced mucin expression in the airways. ACC alone may increase mucin expression in noninfected mucosa, but it decreased bacteria-induced mucin expression. Further studies are warranted to evaluate whether the effect of DEX or ACC is clinically relevant. PMID:17600317

  20. Perspectives of bacterial ACC deaminase in phytoremediation.

    PubMed

    Arshad, Muhammad; Saleem, Muhammad; Hussain, Sarfraz

    2007-08-01

    Phytoremediation of contaminated soil and water environments is regulated and coordinated by the plant root system, yet root growth is often inhibited by pollutant-induced stress. Prolific root growth could maximize rates of hyperaccumulation of inorganic contaminants or rhizodegradation of organic pollutants, and thus accelerate phytoremediation. Accelerated ethylene production in response to stress induced by contaminants is known to inhibit root growth and is considered as a major limitation in improving phytoremediation efficiency. Recent work shows that bacterial 1-aminocyclopropane-1-carboxylate (ACC) deaminase regulates ethylene levels in plants by metabolizing its precursor ACC into alpha-ketobutyric acid and ammonia. Plants inoculated with ACC deaminase bacteria or transgenic plants that express bacterial ACC deaminase genes can regulate their ethylene levels and consequently contribute to a more extensive root system. Such proliferation of roots in contaminated soil can lead to enhanced uptake of heavy metals or rhizodegradation of xenobiotics. PMID:17573137

  1. ACC interleukin-10 gene promoter haplotype as a breast cancer risk factor predictor among Jordanian females

    PubMed Central

    Atoum, Manar Fayiz

    2016-01-01

    Introduction Interleukin-10 (IL-10) is a multifactorial cytokine with a complex biological role in breast cancer. The aims of this study were to investigate any association between IL-10 gene promoter polymorphisms, 1082A>/G, −819T>C, and −592A>C, or haplotypes and breast cancer risk among Jordanian women and to evaluate any association between the most common haplotype with clinicopathological features of breast cancer. Patients and methods A total of 202 breast cancer patients and 210 age-matched healthy control subjects were genotyped for −1082A/G, −819T/C, and −592A/C single nucleotide polymorphisms in the promoter region of the IL-10 gene by polymerase chain reaction-restriction fragment length polymorphism. Study patients and control subjects were recruited from Prince Hamzah Hospital, Amman, Jordan (2012–2013). Ethical approval and signed consent forms were signed by all participants. DNA was extracted, and polymerase chain reaction fragments were amplified and restriction digested by MnII, MaeIII, and RsaI. Results This study showed no statistically significant difference between −1082A/G, −819T/C, and −592A/C IL-10 genotypes or alleles among breast cancer patients or controls. Four different haplotypes ATA, ACC, GTA, and ACA within the IL-10 promoter gene were determined among both breast cancer and control groups. The most frequent haplotype was ACC among breast cancer patients and controls (41.6% and 40.7%, respectively). No statistical differences in these haplotypes among breast cancer patients or controls were determined. Analysis of the most common ACC haplotype showed statistical difference in positive estrogen receptor (P=0.022), positive progesterone receptor (P=0.004), cancer grade (P=0.0001), and cancer stage (P=0.009) among the ACC haplotype compared to non-ACC haplotype. Conclusion To our knowledge, this is the first report studying the association of IL-10 haplotype with breast cancer risk events among Jordanian females. The

  2. Molecular evolution and sequence divergence of plant chalcone synthase and chalcone synthase-Like genes.

    PubMed

    Han, Yingying; Zhao, Wenwen; Wang, Zhicui; Zhu, Jingying; Liu, Qisong

    2014-06-01

    Plant chalcone synthase (CHS) and CHS-Like (CHSL) proteins are polyketide synthases. In this study, we evaluated the molecular evolution of this gene family using representative types of CHSL genes, including stilbene synthase (STS), 2-pyrone synthase (2-PS), bibenzyl synthase (BBS), acridone synthase (ACS), biphenyl synthase (BIS), benzalacetone synthase, coumaroyl triacetic acid synthase (CTAS), and benzophenone synthase (BPS), along with their CHS homologs from the same species of both angiosperms and gymnosperms. A cDNA-based phylogeny indicated that CHSLs had diverse evolutionary patterns. STS, ACS, and 2-PS clustered with CHSs from the same species (late diverged pattern), while CTAS, BBS, BPS, and BIS were distant from their CHS homologs (early diverged pattern). The amino-acid phylogeny suggested that CHS and CHSL proteins formed clades according to enzyme function. The CHSs and CHSLs from Polygonaceae and Arachis had unique evolutionary histories. Synonymous mutation rates were lower in late diverged CHSLs than in early diverged ones, indicating that gene duplications occurred more recently in late diverged CHSLs than in early diverged ones. Relative rate tests proved that late diverged CHSLs had unequal rates to CHSs from the same species when using fatty acid synthase, which evolved from the common ancestor with the CHS superfamily, as the outgroup, while the early diverged lineages had equal rates. This indicated that late diverged CHSLs experienced more frequent mutation than early diverged CHSLs after gene duplication, allowing obtaining new functions in relatively short period of time. PMID:24849013

  3. ACC Study Guide Series (Revised Edition).

    ERIC Educational Resources Information Center

    Staples, Katherine; And Others

    Designed for the beginning college student who needs to search for information, prepare written assignments, or take tests, the ACC (Austin Community College) Study Guide Series comprises 17 one-page study guides. Printed on card stock with colored headings, the guides are highlighted with cartoon illustrations and are intended to provide…

  4. 1-MCP EFFECTS ON ANTIOXIDANT ACTIVITY AND GENE EXPRESSION OF ACC-SYNTHASE AND ACC-OXIDASE IN COTTON FLOWERS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cotton remains an important cash crop for farmers in the southern United States. When temperatures rise above 32oC the in vivo fertilization efficiency of cotton is reduced resulting in decreased seed production and potentially decreased yields. Under stress, the plant hormone ethylene is manufact...

  5. Pleiotropic Effect of AccD5 and AccE5 Depletion in Acyl-Coenzyme A Carboxylase Activity and in Lipid Biosynthesis in Mycobacteria

    PubMed Central

    Bazet Lyonnet, Bernardo; Diacovich, Lautaro; Cabruja, Matías; Bardou, Fabienne; Quémard, Annaïk; Gago, Gabriela; Gramajo, Hugo

    2014-01-01

    Mycobacteria contain a large variety of fatty acids which are used for the biosynthesis of several complex cell wall lipids that have been implicated in the ability of the organism to resist host defenses. The building blocks for the biosynthesis of all these lipids are provided by a fairly complex set of acyl-CoA carboxylases (ACCases) whose subunit composition and roles within these organisms have not yet been clearly established. Previous biochemical and structural studies provided strong evidences that ACCase 5 from Mycobacterium tuberculosis is formed by the AccA3, AccD5 and AccE5 subunits and that this enzyme complex carboxylates acetyl-CoA and propionyl-CoA with a clear substrate preference for the latest. In this work we used a genetic approach to unambiguously demonstrate that the products of both accD5 and accE5 genes are essential for the viability of Mycobacterium smegmatis. By obtaining a conditional mutant on the accD5-accE5 operon, we also demonstrated that the main physiological role of this enzyme complex was to provide the substrates for fatty acid and mycolic acid biosynthesis. Furthermore, enzymatic and biochemical analysis of the conditional mutant provided strong evidences supporting the notion that AccD5 and/or AccE5 have an additional role in the carboxylation of long chain acyl-CoA prior to mycolic acid condensation. These studies represent a significant step towards a better understanding of the roles of ACCases in mycobacteria and confirm ACCase 5 as an interesting target for the development of new antimycobacterial drugs. PMID:24950047

  6. Cloning and sequence of two different cDNAs encoding 1-aminocyclopropane-1-carboxylate synthase in tomato.

    PubMed

    Van der Straeten, D; Van Wiemeersch, L; Goodman, H M; Van Montagu, M

    1990-06-01

    1-Aminocyclopropane-1-carboxylate synthase (ACC synthase; S-adenosyl-L-methionine methylthioadenosine-lyase, EC 4.4.1.14), the key enzyme in ethylene biosynthesis, was purified 5000-fold from induced tomato pericarp. ACC synthase activity was unambiguously correlated with a 45-kDa protein by two independent methods. Peptide sequences were obtained both from the N terminus after electroblotting and from tryptic peptides separated by reversed-phase chromatography. Mixed oligonucleotide probes were used to screen a lambda gt11 library prepared from RNA of induced pericarp tissue. Putative ACC synthase clones were isolated with a frequency of 0.01%. One of these contained a 1.9-kilobase insert with a single open reading frame encoding a polypeptide of 55 kDa. A second, partial cDNA clone was found that differed from the first one in 18% of its bases. Genomic Southern blotting suggests possible tandem organization of the two genes in tomato. The entire coding region was expressed in Escherichia coli and the denatured recombinant polypeptide was used to raise polyclonal antibodies. The antibody preparation both immunoinhibits and immunoprecipitates ACC synthase activity from an enriched tomato extract, confirming the identity of the clone. Northern blot analysis demonstrates that the ACC synthase messenger accumulation is coordinated with fruit ripening. PMID:2191304

  7. ATP synthase.

    PubMed

    Junge, Wolfgang; Nelson, Nathan

    2015-01-01

    Oxygenic photosynthesis is the principal converter of sunlight into chemical energy. Cyanobacteria and plants provide aerobic life with oxygen, food, fuel, fibers, and platform chemicals. Four multisubunit membrane proteins are involved: photosystem I (PSI), photosystem II (PSII), cytochrome b6f (cyt b6f), and ATP synthase (FOF1). ATP synthase is likewise a key enzyme of cell respiration. Over three billion years, the basic machinery of oxygenic photosynthesis and respiration has been perfected to minimize wasteful reactions. The proton-driven ATP synthase is embedded in a proton tight-coupling membrane. It is composed of two rotary motors/generators, FO and F1, which do not slip against each other. The proton-driven FO and the ATP-synthesizing F1 are coupled via elastic torque transmission. Elastic transmission decouples the two motors in kinetic detail but keeps them perfectly coupled in thermodynamic equilibrium and (time-averaged) under steady turnover. Elastic transmission enables operation with different gear ratios in different organisms. PMID:25839341

  8. 5th International ACC Symposium: Hereditary Predisposition to Childhood ACC and the Associated Molecular Phenotype: 5th International ACC Symposium Session: Not Just for Kids!

    PubMed

    Else, Tobias; Rodriguez-Galindo, Carlos

    2016-02-01

    Adrenocortical carcinoma (ACC) affects children and adults. Roughly 50% of very early onset ACCs occur in children with germline TP53 mutations. Several recent studies have extended our understanding in basic, clinical, and translational genetics with regard to TP53 germline predisposition in ACC patients. The recent description of the molecular landscape of pediatric ACCs provided insight into differences of tumors arising in patients with and without TP53 germline mutation. Another recent important finding is that not all TP53 mutations are equal in their tumor suppressing potential. It has now been shown that family histories as well as molecular characteristics of preserved TP53 functions vary greatly between mutations. It also has become clear that adult patients with ACC often harbor germline mutations causing hereditary syndromes, including Li-Fraumeni syndrome (LFS), Lynch syndrome, and multiple endocrine neoplasia type 1 (MEN1). PMID:26660147

  9. 24 CFR 982.154 - ACC reserve account.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 4 2010-04-01 2010-04-01 false ACC reserve account. 982.154... and PHA Administration of Program § 982.154 ACC reserve account. (a) HUD may establish and maintain an unfunded reserve account for the PHA program from available budget authority under the consolidated...

  10. Acc homoeoloci and the evolution of wheat genomes

    PubMed Central

    Chalupska, D.; Lee, H. Y.; Faris, J. D.; Evrard, A.; Chalhoub, B.; Haselkorn, R.; Gornicki, P.

    2008-01-01

    The DNA sequences of wheat Acc-1 and Acc-2 loci, encoding the plastid and cytosolic forms of the enzyme acetyl-CoA carboxylase, were analyzed with a view to understanding the evolution of these genes and the origin of the three genomes in modern hexaploid wheat. Acc-1 and Acc-2 loci from each of the wheats Triticum urartu (A genome), Aegilops tauschii (D genome), Triticum turgidum (AB genome), and Triticum aestivum (ABD genome), as well as two Acc-2-related pseudogenes from T. urartu were sequenced. The 2.3–2.4 Mya divergence time calculated here for the three homoeologous chromosomes, on the basis of coding and intron sequences of the Acc-1 genes, is at the low end of other estimates. Our clock was calibrated by using 60 Mya for the divergence between wheat and maize. On the same time scale, wheat and barley diverged 11.6 Mya, based on sequences of Acc and other genes. The regions flanking the Acc genes are not conserved among the A, B, and D genomes. They are conserved when comparing homoeologous genomes of diploid, tetraploid, and hexaploid wheats. Substitution rates in intergenic regions consisting primarily of repetitive sequences vary substantially along the loci and on average are 3.5-fold higher than the Acc intron substitution rates. The composition of the Acc homoeoloci suggests haplotype divergence exceeding in some cases 0.5 Mya. Such variation might result in a significant overestimate of the time since tetraploid wheat formation, which occurred no more than 0.5 Mya. PMID:18599450

  11. Acc homoeoloci and the evolution of wheat genomes.

    PubMed

    Chalupska, D; Lee, H Y; Faris, J D; Evrard, A; Chalhoub, B; Haselkorn, R; Gornicki, P

    2008-07-15

    The DNA sequences of wheat Acc-1 and Acc-2 loci, encoding the plastid and cytosolic forms of the enzyme acetyl-CoA carboxylase, were analyzed with a view to understanding the evolution of these genes and the origin of the three genomes in modern hexaploid wheat. Acc-1 and Acc-2 loci from each of the wheats Triticum urartu (A genome), Aegilops tauschii (D genome), Triticum turgidum (AB genome), and Triticum aestivum (ABD genome), as well as two Acc-2-related pseudogenes from T. urartu were sequenced. The 2.3-2.4 Mya divergence time calculated here for the three homoeologous chromosomes, on the basis of coding and intron sequences of the Acc-1 genes, is at the low end of other estimates. Our clock was calibrated by using 60 Mya for the divergence between wheat and maize. On the same time scale, wheat and barley diverged 11.6 Mya, based on sequences of Acc and other genes. The regions flanking the Acc genes are not conserved among the A, B, and D genomes. They are conserved when comparing homoeologous genomes of diploid, tetraploid, and hexaploid wheats. Substitution rates in intergenic regions consisting primarily of repetitive sequences vary substantially along the loci and on average are 3.5-fold higher than the Acc intron substitution rates. The composition of the Acc homoeoloci suggests haplotype divergence exceeding in some cases 0.5 Mya. Such variation might result in a significant overestimate of the time since tetraploid wheat formation, which occurred no more than 0.5 Mya. PMID:18599450

  12. Single phosphorylation sites in Acc1 and Acc2 regulate lipid homeostasis and the insulin–sensitizing effects of metformin

    PubMed Central

    Fullerton, Morgan D.; Galic, Sandra; Marcinko, Katarina; Sikkema, Sarah; Pulinilkunnil, Thomas; Chen, Zhi–Ping; O’Neill, Hayley M.; Ford, Rebecca J.; Palanivel, Rengasamy; O’Brien, Matthew; Hardie, D. Grahame; Macaulay, S. Lance; Schertzer, Jonathan D.; Dyck, Jason R. B.; van Denderen, Bryce J.; Kemp, Bruce E.; Steinberg, Gregory R.

    2016-01-01

    The obesity epidemic has led to an increased incidence of non–alcoholic fatty liver disease (NAFLD) and type 2 diabetes. AMP–activated protein kinase (Ampk) regulates energy homeostasis and is activated by cellular stress, hormones and the widely prescribed anti–type 2 diabetic drug metformin1,2. Ampk phosphorylates murine acetyl–CoA carboxylase3,4 (Acc) 1 at Ser79 and Acc2 at Ser212, inhibiting the conversion of acetyl–CoA to malonyl–CoA, a precursor in fatty acid synthesis5 as well as an allosteric inhibitor of fatty acid transport into mitochondria for oxidation6. To test the physiological impact of these phosphorylation events we generated mice with alanine knock–in mutations in both Acc1 (Ser79) and Acc2 (Ser212) (Acc double knock–in, AccDKI). These mice have elevated lipogenesis and lower fatty acid oxidation compared to wild–type (WT) mice, which contribute to the progression of insulin resistance, glucose intolerance and NAFLD, but not obesity. Remarkably, AccDKI mice made obese by high–fat feeding, are refractory to the lipid–lowering and insulin–sensitizing effects of metformin. These findings establish that inhibitory phosphorylation of Acc by Ampk is essential for the control of lipid metabolism, and in the setting of obesity, for metformin–induced improvements in insulin action. PMID:24185692

  13. Characterization of transcriptional profiles of MA-ACS1 and MA-ACO1 genes in response to ethylene, auxin, wounding, cold and different photoperiods during ripening in banana fruit.

    PubMed

    Choudhury, Swarup Roy; Roy, Sujit; Sengupta, Dibyendu N

    2008-12-01

    The ripening-specific genes MA-ACS1 (Musa acuminata ACC synthase1) and MA-ACO1 (M. acuminata ACC oxidase 1) are regulated in response to a wide variety of factors. Here, we have studied the differential transcript accumulation pattern and protein levels of MA-ACS1 and MA-ACO1 genes in response to ethylene, auxin, wounding and low temperature in preclimacteric banana fruit. We have shown that exogenous application of ethylene and auxin induced the expression of MA-ACS1, while MA-ACO1 showed marginal expression following ethylene treatment in preclimacteric stage. Auxin did not induce MA-ACO1 expression. Thus, auxin-treated banana fruits showed lower ethylene production rate as compared to ethylene-treated fruits. Conversely, wounding and cold treatment down-regulated the expression of both the genes and thus inhibited ethylene production. Furthermore, we have detected a GCC-box putative ethylene-responsive element (ERE)- and an auxin-responsive element (ARE)-specific DNA-binding activity in the banana pulp and studied the ethylene and auxin responsive characteristics of the GCC-box and ARE (TGTCTC) containing synthetic promoter fragments. In addition, we have detected an enhanced ethylene production rate and expression level of MA-ACS1 and MA-ACO1 genes along with a strong GCC-box-specific DNA-binding activity following exposure to constant dark period for 8d at the preclimacteric stage. Together, our study provides interesting information about the regulation of expression of MA-ACS1 and MA-ACO1 genes in response to various factors during ripening in banana fruit, which may have physiological relevance concerning ethylene biosynthesis during post-harvest conditions. PMID:18554749

  14. Adrenocortical cancer (ACC) - literature overview and own experience.

    PubMed

    Dworakowska, Dorota; Drabarek, Agata; Wenzel, Ingrid; Babińska, Anna; Świątkowska-Stodulska, Renata; Sworczak, Krzysztof

    2014-01-01

    Adrenocortical carcinoma (ACC) is a malignant endocrine tumour. The rarity of the disease has stymied therapeutic development. Age distribution shows two peaks: the first and fifth decades of life, with children and women more frequently affected. Although 60-70% of ACCs are biochemically found to overproduce hormones, it is not clinically apparent in many cases. If present, endocrine symptoms include signs of hypercortisolaemia, virilisation or gynaecomastia. ACC carries a poor prognosis, and a cure can be achieved only by complete surgical resection. Mitotane is used both as an adjuvant treatment and also in non-operative patients. The role of radio- and chemotherapy is still controversial. The post-operative disease free survival is low and oscillates around 30% due to high tumour recurrence rate. The diagnosis is based on tumour histological assessment with the use of the Weiss score, however urinary steroid profiling (if available) can serve to differentiate between ACC and other adrenal tumours. Conventional prognostic markers in ACC include stage and grade of disease, and, as currently reported, the presence of hypercortisolaemia. Molecular analysis has had a significant impact on the understanding of the pathogenetic mechanism of ACC development and the evaluation of prognostic and predictive markers, among which alterations of the IGF system, the Wnt pathway, p53 and molecules involved in cancer cell invasion properties and angiogenesis seem to be very promising. We here summarise our own experience related to the management of ACC and present a literature overview. We have not aimed to include a detailed summary of the molecular alterations biology described in ACC, as this has already been addressed in other papers. PMID:25554619

  15. Effects of bacterial ACC deaminase on Brassica napus gene expression.

    PubMed

    Stearns, Jennifer C; Woody, Owen Z; McConkey, Brendan J; Glick, Bernard R

    2012-05-01

    Plants in association with plant growth-promoting rhizobacteria can benefit from lower plant ethylene levels through the action of the bacterial enzyme 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase. This enzyme cleaves the immediate biosynthetic precursor of ethylene, ACC. Ethylene is responsible for many aspects of plant growth and development but, under stressful conditions, it exacerbates stress symptoms. The ACC deaminase-containing bacterium Pseudomonas putida UW4 is a potent plant growth-promoting strain and, as such, was used to elaborate the detailed role of bacterial ACC deaminase in Brassica napus (canola) plant growth promotion. Transcriptional changes in bacterially treated canola plants were investigated with the use of an Arabidopsis thaliana oligonucleotide microarray. A heterologous approach was necessary because there are few tools available at present to measure global expression changes in nonmodel organisms, specifically with the sensitivity of microarrays. The results indicate that the transcription of genes involved in plant hormone regulation, secondary metabolism, and stress response was altered in plants by the presence of the bacterium, whereas the upregulation of genes for auxin response factors and the downregulation of stress response genes was observed only in the presence of bacterial ACC deaminase. These results support the suggestion that there is a direct link between ethylene and the auxin response, which has been suggested from physiological studies, and provide more evidence for the stress-reducing benefits of ACC deaminase-expressing plant growth-promoting bacteria. PMID:22352713

  16. Stilbene Synthase and Chalcone Synthase 1

    PubMed Central

    Rolfs, Claus-Henning; Kindl, Helmut

    1984-01-01

    Cultured cells of Picea excelsa capable of forming stilbenes and flavanoids have been established. Unlike needles of intact plants containing piceatannol (3,3′,4′,5-tetrahydroxystilbene) and stilbene glycosides the cultured cells converted phenylalanine and p-coumaric acid primarily into resveratrol monomethyl ether (3,4′-dihydroxy-5-methoxystilbene) and naringenin. Partially purified enzyme preparations were assayed for chalcone synthase as well as for stilbene synthase activity converting malonyl-CoA plus p-coumaroyl-CoA into 3,4′,5-trihydroxystilbene (resveratrol). Although stilbene synthase and chalcone synthase use the same substrates and exhibit similar molecular properties, i.e. molecular weight and subunit molecular weight, they are two different proteins. This difference was demonstrated by gel electrophoresis and by means of monospecific antibodies. PMID:16663649

  17. Expression of apple 1-aminocyclopropane-1-carboxylate synthase in Escherichia coli: kinetic characterization of wild-type and active-site mutant forms.

    PubMed Central

    White, M F; Vasquez, J; Yang, S F; Kirsch, J F

    1994-01-01

    The pyridoxal phosphate-dependent enzyme 1-aminocyclopropane-1-carboxylate synthase (ACC synthase; S-adenosyl-L-methionine methylthioadenosine-lyase, EC 4.4.1.14) catalyzes the conversion of S-adenosylmethionine (AdoMet) to ACC and 5'-methylthioadenosine, the committed step in ethylene biosynthesis in plants. Apple ACC synthase was overexpressed in Escherichia coli (3 mg/liter) and purified to near homogeneity. A continuous assay was developed by coupling the ACC synthase reaction to the deamination of 5'-methylthioadenosine by adenosine deaminase (adenosine aminohydrolase, EC 3.5.4.4) from Aspergillus oryzae. The enzyme is dimeric, with kcat = 9s-1 per monomer and Km = 12 microM for AdoMet. The pyridoxal phosphate-binding site of ACC synthase appears to be highly homologous to that of aspartate aminotransferase, suggesting similar roles for corresponding residues. Site-directed mutagenesis of Lys-273, Arg-407, and Tyr-233 (corresponding to residues 258, 386, and 225 in aspartate aminotransferase) and kinetic analyses of the mutants confirms their importance in the ACC synthase mechanism. The Lys-273 to Ala mutant has no detectable activity, supporting the identification of this residue as the base catalyzing C alpha proton abstraction. Mutation of Arg-407 to Lys results in a precipitous drop in kcat/Km and an increase in Km for AdoMet of at least 20-fold, in accordance with its proposed role as principal ligand for the substrate alpha-carboxylate group. Replacement of Tyr-233 with Phe causes a 24-fold increase in the Km for AdoMet and no change in kcat, suggesting that this residue plays a role in orienting the pyridoxal phosphate cofactor in the active site. Images Fig. 4 PMID:7809054

  18. Cellulose synthase interacting protein

    PubMed Central

    Somerville, Chris

    2010-01-01

    Cellulose is the most abundant biopolymer on earth. The great abundance of cellulose places it at the forefront as a primary source of biomass for renewable biofuels. However, the knowledge of how plant cells make cellulose remains very rudimentary. Cellulose microfibrils are synthesized at the plasma membrane by hexameric protein complexes, also known as cellulose synthase complexes. The only known components of cellulose synthase complexes are cellulose synthase (CESA) proteins until the recent identification of a novel component. CSI1, which encodes CESA interacting protein 1 (CSI1) in Arabidopsis. CSI1, as the first non-CESA proteins associated with cellulose synthase complexes, opens up many opportunities. PMID:21150290

  19. Discovery and optimization of antibacterial AccC inhibitors

    SciTech Connect

    Cheng, Cliff C.; Shipps, Jr., Gerald W.; Yang, Zhiwei; Sun, Binyuan; Kawahata, Noriyuki; Soucy, Kyle A.; Soriano, Aileen; Orth, Peter; Xiao, Li; Mann, Paul; Black, Todd

    2010-09-17

    The biotin carboxylase (AccC) is part of the multi-component bacterial acetyl coenzyme-A carboxylase (ACCase) and is essential for pathogen survival. We describe herein the affinity optimization of an initial hit to give 2-(2-chlorobenzylamino)-1-(cyclohexylmethyl)-1H-benzo[d]imidazole-5-carboxamide (1), which was identified using our proprietary Automated Ligand Identification System (ALIS). The X-ray co-crystal structure of 1 was solved and revealed several key interactions and opportunities for further optimization in the ATP site of AccC. Structure Based Drug Design (SBDD) and parallel synthetic approaches resulted in a novel series of AccC inhibitors, exemplified by (R)-2-(2-chlorobenzylamino)-1-(2,3-dihydro-1H-inden-1-yl)-1H-imidazo[4,5-b]pyridine-5-carboxamide (40). This compound is a potent and selective inhibitor of bacterial AccC with an IC{sub 50} of 20 nM and a MIC of 0.8 {micro}g/mL against a sensitized strain of Escherichia coli (HS294 E. coli).

  20. The ACCE 2012 Study Tour: Reflections on Reoccurring Themes

    ERIC Educational Resources Information Center

    Clements, Di; Grover, David; Grover, Pam; Hearne, Dominic; Knipe, Steven; Martin, Kim; Pazzi, Georgina; Pollard, Edward; Prestridge, Sarah

    2012-01-01

    Transformational leadership is essential in education as it empowers educators to make positive changes to the way they think, feel and act in improving learning for all. Reflection is a vital element of leading the change process. In relation to participating in the ACCE study tour experience, reflection allows one to sit and think about the…

  1. Southern blight disease of tomato control by 1-aminocyclopropane-1-carboxylate (ACC) deaminase producing Paenibacillus lentimorbus B-30488.

    PubMed

    Dixit, Ritu; Agrawal, Lalit; Gupta, Swati; Kumar, Manoj; Yadav, Sumit; Chauhan, Puneet Singh; Nautiyal, Chandra Shekhar

    2016-01-01

    Tomato cultivation is highly susceptible for soil born diseases and among them southern blight disease caused by Scelerotium rolfsii is very common. For its management use of chemical fungicides is not very successful as their spores are able to survive for many years in the soil. As an alternative eco-friendly approach to control the disease antagonistic microbes are being characterized.Among them plant growth promoting rhizobacteria Paenibacillus lentimorbus B-30488 (B-30488) with antagonistic properties, multiple PGP attributes stress tolerance and ACC deaminase enzyme activity is characterized to decipher its mode of action against S. rolfsii under in vitro and in vivo conditions. In vitro results obtained from this study clearly demonstrate that B-30488 has ability to show antagonistic properties under different abiotic stresses against S. rolfsii. Similar results were also obtained from in vivo experiments where B-30488 inoculation has efficiently controlled the disease caused by S. rolfsii and improve the plant growth. Deleterious enhanced ethylene level in S. rolfsii infected plants was also ameliorated by inoculation of ACC deaminase producing B-30488. The ACC accumulation, ACO and ACS activities were also modulated in S. rolfsii infected plants. Results from defense enzymes and other biochemical attributes were also support the role of B-30488 inoculation in ameliorating the biotic stress caused by S. rolfsii in tomato plants. These results were further validated by pathogen related gene expression analysis by real time PCR. Overall results from the present study may be concluded that ACC deaminase producing B-30488 has ability to control the southern blight disease caused by S. rolfsii and commercial bioinoculant package may be developed. PMID:26825539

  2. Southern blight disease of tomato control by 1-aminocyclopropane-1-carboxylate (ACC) deaminase producing Paenibacillus lentimorbus B-30488

    PubMed Central

    Dixit, Ritu; Agrawal, Lalit; Gupta, Swati; Kumar, Manoj; Yadav, Sumit; Chauhan, Puneet Singh; Nautiyal, Chandra Shekhar

    2016-01-01

    abstract Tomato cultivation is highly susceptible for soil born diseases and among them southern blight disease caused by Scelerotium rolfsii is very common. For its management use of chemical fungicides is not very successful as their spores are able to survive for many years in the soil. As an alternative eco-friendly approach to control the disease antagonistic microbes are being characterized.Among them plant growth promoting rhizobacteria Paenibacillus lentimorbus B-30488 (B-30488) with antagonistic properties, multiple PGP attributes stress tolerance and ACC deaminase enzyme activity is characterized to decipher its mode of action against S. rolfsii under in vitro and in vivo conditions. In vitro results obtained from this study clearly demonstrate that B-30488 has ability to show antagonistic properties under different abiotic stresses against S. rolfsii. Similar results were also obtained from in vivo experiments where B-30488 inoculation has efficiently controlled the disease caused by S. rolfsii and improve the plant growth. Deleterious enhanced ethylene level in S. rolfsii infected plants was also ameliorated by inoculation of ACC deaminase producing B-30488. The ACC accumulation, ACO and ACS activities were also modulated in S. rolfsii infected plants. Results from defense enzymes and other biochemical attributes were also support the role of B-30488 inoculation in ameliorating the biotic stress caused by S. rolfsii in tomato plants. These results were further validated by pathogen related gene expression analysis by real time PCR. Overall results from the present study may be concluded that ACC deaminase producing B-30488 has ability to control the southern blight disease caused by S. rolfsii and commercial bioinoculant package may be developed. PMID:26825539

  3. Isolation and molecular characterization of 1-aminocyclopropane-1-carboxylic acid synthase genes in Hevea brasiliensis.

    PubMed

    Zhu, Jia-Hong; Xu, Jing; Chang, Wen-Jun; Zhang, Zhi-Li

    2015-01-01

    Ethylene is an important factor that stimulates Hevea brasiliensis to produce natural rubber. 1-Aminocyclopropane-1-carboxylic acid synthase (ACS) is a rate-limiting enzyme in ethylene biosynthesis. However, knowledge of the ACS gene family of H. brasiliensis is limited. In this study, nine ACS-like genes were identified in H. brasiliensis. Sequence and phylogenetic analysis results confirmed that seven isozymes (HbACS1-7) of these nine ACS-like genes were similar to ACS isozymes with ACS activity in other plants. Expression analysis results showed that seven ACS genes were differentially expressed in roots, barks, flowers, and leaves of H. brasiliensis. However, no or low ACS gene expression was detected in the latex of H. brasiliensis. Moreover, seven genes were differentially up-regulated by ethylene treatment. These results provided relevant information to help determine the functions of the ACS gene in H. brasiliensis, particularly the functions in regulating ethylene stimulation of latex production. PMID:25690030

  4. 1-aminocyclopropane-1-carboxylic acid (ACC) concentration and ACC synthase expression in soybean roots and root tips and soybean cyst nematode (Heterodera glycines) colonized root pieces

    Technology Transfer Automated Retrieval System (TEKTRAN)

    It's fairly well established that a functional ethylene response path is important to root knot and cyst nematode colonization of plant roots. However, ethylene plays many roles in root development and the role of ethylene in nematode colonization of roots may be indirect, e.g. lateral root initiati...

  5. An Open Letter to the Professional Communities of Australian Council for Computers in Education (ACCE)

    ERIC Educational Resources Information Center

    Williams, Michelle

    2005-01-01

    This article presents an open letter to the Professional Communities of Australian Council for Computers in Education (ACCE). In preparing for this article, the author looked back over the contributions of other fellows in publications and ACCE Minutes, and recognized that each had led the ACCE family in this endeavor. Creating direction was the…

  6. In vitro synthesis and stabilization of amorphous calcium carbonate (ACC) nanoparticles within liposomes

    SciTech Connect

    Tester, Chantel C.; Brock, Ryan E.; Wu, Ching-Hsuan; Krejci, Minna R.; Weigand, Steven; Joester, Derk

    2012-02-07

    We show that amorphous calcium carbonate (ACC) can be synthesized in phospholipid bilayer vesicles (liposomes). Liposome-encapsulated ACC nanoparticles are stable against aggregation, do not crystallize for at least 20 h, and are ideally suited to investigate the influence of lipid chemistry, particle size, and soluble additives on ACC in situ.

  7. Direct observations of the ACC transport across the Kerguelen Plateau

    NASA Astrophysics Data System (ADS)

    Park, Young-Hyang; Vivier, Frédéric; Roquet, Fabien; Kestenare, Elodie

    2009-09-01

    Major pathways and transport of the Antarctic Circumpolar Current (ACC) crossing the Kerguelen Plateau were directly observed during the 2009 Track cruise. The net eastward transport to the south of the Heard/McDonald Islands is estimated as 56 Sv (1 Sv = 106 m3 s-1), 43 Sv of which is tightly channelled into the Fawn Trough that appears as a predominant cross-plateau gateway of circumpolar flow associated with the Southern ACC Front (SACCF). There are also two secondary passages, with one (6 Sv) being attached to the nearshore slope just south of the Heard/McDonald Islands and the other (7 Sv) passing through the northern Princess Elizabeth Trough. With an additional 2 Sv inferred just south of the Kerguelen Islands, the transport across the entire plateau amounts to 58 Sv, accounting for ˜40% of the total ACC transport transiting through the region, 147-152 Sv, quantities consistent with other independent estimates in the Indian sector of the Southern Ocean.

  8. Reward salience and risk aversion underlie differential ACC activity in substance dependence

    PubMed Central

    Alexander, William H.; Fukunaga, Rena; Finn, Peter; Brown, Joshua W.

    2015-01-01

    The medial prefrontal cortex, especially the dorsal anterior cingulate cortex (ACC), has long been implicated in cognitive control and error processing. Although the association between ACC and behavior has been established, it is less clear how ACC contributes to dysfunctional behavior such as substance dependence. Evidence from neuroimaging studies investigating ACC function in substance users is mixed, with some studies showing disengagement of ACC in substance dependent individuals (SDs), while others show increased ACC activity related to substance use. In this study, we investigate ACC function in SDs and healthy individuals performing a change signal task for monetary rewards. Using a priori predictions derived from a recent computational model of ACC, we find that ACC activity differs between SDs and controls in factors related to reward salience and risk aversion between SDs and healthy individuals. Quantitative fits of a computational model to fMRI data reveal significant differences in best fit parameters for reward salience and risk preferences. Specifically, the ACC in SDs shows greater risk aversion, defined as concavity in the utility function, and greater attention to rewards relative to reward omission. Furthermore, across participants risk aversion and reward salience are positively correlated. The results clarify the role that ACC plays in both the reduced sensitivity to omitted rewards and greater reward valuation in SDs. Clinical implications of applying computational modeling in psychiatry are also discussed. PMID:26106528

  9. ACC2 Is Expressed at High Levels Human White Adipose and Has an Isoform with a Novel N-Terminus

    PubMed Central

    Raymond, Christopher K.; Garrett-Engele, Philip; Ohwaki, Kenji; Kan, Zhengyan; Kusunoki, Jun; Johnson, Jason M.

    2009-01-01

    Acetyl-CoA carboxylases ACC1 and ACC2 catalyze the carboxylation of acetyl-CoA to malonyl-CoA, regulating fatty-acid synthesis and oxidation, and are potential targets for treatment of metabolic syndrome. Expression of ACC1 in rodent lipogenic tissues and ACC2 in rodent oxidative tissues, coupled with the predicted localization of ACC2 to the mitochondrial membrane, have suggested separate functional roles for ACC1 in lipogenesis and ACC2 in fatty acid oxidation. We find, however, that human adipose tissue, unlike rodent adipose, expresses more ACC2 mRNA relative to the oxidative tissues muscle and heart. Human adipose, along with human liver, expresses more ACC2 than ACC1. Using RT-PCR, real-time PCR, and immunoprecipitation we report a novel isoform of ACC2 (ACC2.v2) that is expressed at significant levels in human adipose. The protein generated by this isoform has enzymatic activity, is endogenously expressed in adipose, and lacks the N-terminal sequence. Both ACC2 isoforms are capable of de novo lipogenesis, suggesting that ACC2, in addition to ACC1, may play a role in lipogenesis. The results demonstrate a significant difference in ACC expression between human and rodents, which may introduce difficulties for the use of rodent models for development of ACC inhibitors. PMID:19190759

  10. An Arabidopsis callose synthase.

    PubMed

    Ostergaard, Lars; Petersen, Morten; Mattsson, Ole; Mundy, John

    2002-08-01

    Beta-1,3-glucan polymers are major structural components of fungal cell walls, while cellulosic beta-1,4-glucan is the predominant polysaccharide in plant cell walls. Plant beta-1,3-glucan, called callose, is produced in pollen and in response to pathogen attack and wounding, but it has been unclear whether callose synthases can also produce cellulose and whether plant cellulose synthases may also produce beta-1,3-glucans. We describe here an Arabidopsis gene, AtGsl5, encoding a plasma membrane-localized protein homologous to yeast beta-1,3-glucan synthase whose expression partially complements a yeast beta-1,3-glucan synthase mutant. AtGsl5 is developmentally expressed at highest levels in flowers, consistent with flowers having high beta-1,3-glucan synthase activities for deposition of callose in pollen. A role for AtGsl5 in callose synthesis is also indicated by AtGsl5 expression in the Arabidopsis mpk4 mutant which exhibits systemic acquired resistance (SAR), elevated beta-1,3-glucan synthase activity, and increased callose levels. In addition, AtGsl5 is a likely target of salicylic acid (SA)-dependent SAR, since AtGsl5 mRNA accumulation is induced by SA in wild-type plants, while expression of the nahG salicylate hydroxylase reduces AtGsl5 mRNA levels in the mpk4 mutant. These results indicate that AtGsl5 is likely involved in callose synthesis in flowering tissues and in the mpk4 mutant. PMID:12081364

  11. Geranyl diphosphate synthase from mint

    SciTech Connect

    Croteau, Rodney Bruce; Wildung, Mark Raymond; Burke, Charles Cullen; Gershenzon, Jonathan

    1999-01-01

    A cDNA encoding geranyl diphosphate synthase from peppermint has been isolated and sequenced, and the corresponding amino acid sequence has been determined. Accordingly, an isolated DNA sequence (SEQ ID No:1) is provided which codes for the expression of geranyl diphosphate synthase (SEQ ID No:2) from peppermint (Mentha piperita). In other aspects, replicable recombinant cloning vehicles are provided which code for geranyl diphosphate synthase or for a base sequence sufficiently complementary to at least a portion of the geranyl diphosphate synthase DNA or RNA to enable hybridization therewith (e.g., antisense geranyl diphosphate synthase RNA or fragments of complementary geranyl diphosphate synthase DNA which are useful as polymerase chain reaction primers or as probes for geranyl diphosphate synthase or related genes). 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 geranyl diphosphate synthase. Thus, systems and methods are provided for the recombinant expression of geranyl diphosphate synthase that may be used to facilitate the production, isolation and purification of significant quantities of recombinant geranyl diphosphate synthase for subsequent use, to obtain expression or enhanced expression of geranyl diphosphate synthase in plants in order to enhance the production of monoterpenoids, to produce geranyl diphosphate in cancerous cells as a precursor to monoterpenoids having anti-cancer properties or may be otherwise employed for the regulation or expression of geranyl diphosphate synthase or the production of geranyl diphosphate.

  12. Geranyl diphosphate synthase from mint

    SciTech Connect

    Croteau, R.B.; Wildung, M.R.; Burke, C.C.; Gershenzon, J.

    1999-03-02

    A cDNA encoding geranyl diphosphate synthase from peppermint has been isolated and sequenced, and the corresponding amino acid sequence has been determined. Accordingly, an isolated DNA sequence (SEQ ID No:1) is provided which codes for the expression of geranyl diphosphate synthase (SEQ ID No:2) from peppermint (Mentha piperita). In other aspects, replicable recombinant cloning vehicles are provided which code for geranyl diphosphate synthase or for a base sequence sufficiently complementary to at least a portion of the geranyl diphosphate synthase DNA or RNA to enable hybridization therewith (e.g., antisense geranyl diphosphate synthase RNA or fragments of complementary geranyl diphosphate synthase DNA which are useful as polymerase chain reaction primers or as probes for geranyl diphosphate synthase or related genes). 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 geranyl diphosphate synthase. Thus, systems and methods are provided for the recombinant expression of geranyl diphosphate synthase that may be used to facilitate the production, isolation and purification of significant quantities of recombinant geranyl diphosphate synthase for subsequent use, to obtain expression or enhanced expression of geranyl diphosphate synthase in plants in order to enhance the production of monoterpenoids, to produce geranyl diphosphate in cancerous cells as a precursor to monoterpenoids having anti-cancer properties or may be otherwise employed for the regulation or expression of geranyl diphosphate synthase or the production of geranyl diphosphate. 5 figs.

  13. Further studies of auxin and ACC induced feminization in the cucumber plant using ethylene inhibitors

    NASA Technical Reports Server (NTRS)

    Takahashi, H.; Jaffe, M. J.

    1984-01-01

    The present study was designed to establish the role of an essential hormone controlling sex expression in cucumber. A potent anti-ethylene agent, AgNO3, completely inhibited pistillate flower formation caused by IAA, ACC or ethephon. Inhibitors of ethylene biosynthesis, AVG and CoCl2 also suppressed feminization due to exogenous IAA or ACC. Though AVG also suppressed ethephon-induced feminization, this may be due to the second effect of AVG rather than the effect on ACC biosynthesis. These results confirm that ethylene is a major factor regulating feminization and that exogenous auxin induces pistillate flower formation through its stimulation of ethylene production, rather than ACC production.

  14. Expression Patterns, Activities and Carbohydrate-Metabolizing Regulation of Sucrose Phosphate Synthase, Sucrose Synthase and Neutral Invertase in Pineapple Fruit during Development and Ripening

    PubMed Central

    Zhang, Xiu-Mei; Wang, Wei; Du, Li-Qing; Xie, Jiang-Hui; Yao, Yan-Li; Sun, Guang-Ming

    2012-01-01

    Differences in carbohydrate contents and metabolizing-enzyme activities were monitored in apical, medial, basal and core sections of pineapple (Ananas comosus cv. Comte de paris) during fruit development and ripening. Fructose and glucose of various sections in nearly equal amounts were the predominant sugars in the fruitlets, and had obvious differences until the fruit matured. The large rise of sucrose/hexose was accompanied by dramatic changes in sucrose phosphate synthase (SPS) and sucrose synthase (SuSy) activities. By contrast, neutral invertase (NI) activity may provide a mechanism to increase fruit sink strength by increasing hexose concentrations. Furthermore, two cDNAs of Ac-sps (accession no. GQ996582) and Ac-ni (accession no. GQ996581) were first isolated from pineapple fruits utilizing conserved amino-acid sequences. Homology alignment reveals that the amino acid sequences contain some conserved function domains. Transcription expression analysis of Ac-sps, Ac-susy and Ac-ni also indicated distinct patterns related to sugar accumulation and composition of pineapple fruits. It suggests that differential expressions of multiple gene families are necessary for sugar metabolism in various parts and developmental stages of pineapple fruit. A cycle of sucrose breakdown in the cytosol of sink tissues could be mediated through both Ac-SuSy and Ac-NI, and Ac-NI could be involved in regulating crucial steps by generating sugar signals to the cells in a temporally and spatially restricted fashion. PMID:22949808

  15. Elevated expression of fatty acid synthase and nuclear localization of carnitine palmitoyltransferase 1C are common among human gliomas.

    PubMed

    Wakamiya, Tomihiro; Suzuki, Satoshi O; Hamasaki, Hideomi; Honda, Hiroyuki; Mizoguchi, Masahiro; Yoshimoto, Koji; Iwaki, Toru

    2014-10-01

    Fatty acid synthase (FASN) and carnitine palmitoyltransferase 1C (CPT1C), a brain-specific isoform of the CPT1 family, are upregulated in certain types of cancers, including gliomas. Acetyl-CoA carboxylase (ACC) catalyzes the carboxylation of acetyl-CoA to malonyl-CoA, the rate-limiting step in fatty acid synthesis, and its phosphorylated form inhibits lipid synthesis. We examined the expression and subcellular localization of these fatty acid metabolism-related molecules in human gliomas. We performed immunostaining of two glioma cell lines (U373MG and U87MG) and 41 surgical specimens of diffuse gliomas with various histological grades (21 with the isocitrate dehydrogenase 1(IDH1) R132H mutation and 20 without the mutation). In the cultured glioma cells, CPT1C and phosphorylated ACC (p-ACC) were mainly localized to the nuclei, whereas FASN localized to the cytoplasm. In the surgical specimens, most glioma tissues showed nuclear staining for CPT1C and p-ACC, and cytoplasmic staining for FASN, regardless of the genetic status of IDH1 and the histological grade. Therefore, elevated cytoplasmic expression of FASN and nuclear localization of CPT1C are common among human diffuse gliomas, which may be regulated by the differential phosphorylation status of ACC in the cellular compartment. PMID:24984811

  16. Hybrid polyketide synthases

    DOEpatents

    Fortman, Jeffrey L.; Hagen, Andrew; Katz, Leonard; Keasling, Jay D.; Poust, Sean; Zhang, Jingwei; Zotchev, Sergey

    2016-05-10

    The present invention provides for a polyketide synthase (PKS) capable of synthesizing an even-chain or odd-chain diacid or lactam or diamine. The present invention also provides for a host cell comprising the PKS and when cultured produces the even-chain diacid, odd-chain diacid, or KAPA. The present invention also provides for a host cell comprising the PKS capable of synthesizing a pimelic acid or KAPA, and when cultured produces biotin.

  17. 24 CFR 985.109 - Default under the Annual Contributions Contract (ACC).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... § 985.109 Default under the Annual Contributions Contract (ACC). HUD may determine that an PHA's failure... 24 Housing and Urban Development 4 2010-04-01 2010-04-01 false Default under the Annual Contributions Contract (ACC). 985.109 Section 985.109 Housing and Urban Development Regulations Relating...

  18. 24 CFR 985.109 - Default under the Annual Contributions Contract (ACC).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... § 985.109 Default under the Annual Contributions Contract (ACC). HUD may determine that an PHA's failure... 24 Housing and Urban Development 4 2011-04-01 2011-04-01 false Default under the Annual Contributions Contract (ACC). 985.109 Section 985.109 Housing and Urban Development REGULATIONS RELATING...

  19. Active intermediates of polyhydroxyalkanoate synthase from Aeromonas caviae in polymerization reaction.

    PubMed

    Numata, Keiji; Motoda, Yoko; Watanabe, Satoru; Tochio, Naoya; Kigawa, Takanori; Doi, Yoshiharu

    2012-11-12

    Polyhydroxyalkanoate (PHA) synthase from Aeromonas caviae FA440 (PhaC(Ac), BAA21815) is one of the most valuable PHA synthase, because of its function to synthesize a practical bioplastic, poly[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyhexanoate] [P(3HB-co-3HHx)]. However, biochemical activity and active intermediates of PhaC(Ac) have not been clarified until now. In the present study, a gene of PhaC(Ac) was cloned and overexpressed by a cell-free protein expression system. Both the polymerization activity and oligomerization behavior of the purified PhaC(Ac) were characterized in order to clarify the active intermediates of PhaC(Ac) based on the hydrodynamic diameters and specific activities of PhaC(Ac). The influences of a substrate, (R)-3-hydroxybutyryl-CoA (3HB-CoA), on the oligomerization of PhaC(Ac) (7.5 μM) were also investigated, and then the Hill coefficient (n = 2.6 ± 0.4) and the microscopic dissociation constant (K(m) = 77 ± 5 μM) were determined. Based on the results, the active intermediate of PhaC(Ac) was concluded to be the dimeric PhaC(Ac) containing 3HB-CoA as an activator for its dimerization. This information is critical for revealing the relationships between its dimerization and function in PHA synthesis. PMID:23043466

  20. Increased expression of fatty acid synthase and acetyl-CoA carboxylase in the prefrontal cortex and cerebellum in the valproic acid model of autism

    PubMed Central

    Chen, Jianling; Wu, Wei; Fu, Yingmei; Yu, Shunying; Cui, Donghong; Zhao, Min; Du, Yasong; Li, Jijun; Li, Xiaohong

    2016-01-01

    The primary aim of the present study was to investigate alterations in enzymes associated with fatty acid synthesis, namely fatty acid synthase (FASN) and acetyl-CoA carboxylase (ACC), in the prefrontal cortex and cerebellum of the valproic acid (VPA)-induced animal model of autism. In this model, pregnant rats were given a single intraperitoneal injection of VPA, and prefrontal cortex and cerebellum samples from their pups were analyzed. The results of western blotting and reverse transcription-quantitative polymerase chain reaction analyses demonstrated that the protein and mRNA expression levels of FASN, ACC and phospho-ACC (pACC) were increased in the prefrontal cortex and cerebellum of the VPA model of autism. Furthermore, in the prefrontal cortex and cerebellum of the VPA model of autism, AMPK expression is increased, whereas PI3K and Akt expression are unchanged. This suggests that disorder of the phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K)/Akt/FASN and/or adenosine 5′-monophosphate-activated protein kinase (AMPK)/ACC pathway may be involved in the pathogenesis of autism. It is hypothesized that fatty acid synthesis participates in autism through PI3K/Akt/FASN and AMPK/ACC pathways. PMID:27602061

  1. New Insights into 1-Aminocyclopropane-1-Carboxylate (ACC) Deaminase Phylogeny, Evolution and Ecological Significance

    PubMed Central

    Nascimento, Francisco X.; Rossi, Márcio J.; Soares, Cláudio R. F. S.; McConkey, Brendan J.; Glick, Bernard R.

    2014-01-01

    The main objective of this work is the study of the phylogeny, evolution and ecological importance of the enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase, the activity of which represents one of the most important and studied mechanisms used by plant growth–promoting microorganisms. The ACC deaminase gene and its regulatory elements presence in completely sequenced organisms was verified by multiple searches in diverse databases, and based on the data obtained a comprehensive analysis was conducted. Strain habitat, origin and ACC deaminase activity were taken into account when analyzing the results. In order to unveil ACC deaminase origin, evolution and relationships with other closely related pyridoxal phosphate (PLP) dependent enzymes a phylogenetic analysis was also performed. The data obtained show that ACC deaminase is mostly prevalent in some Bacteria, Fungi and members of Stramenopiles. Contrary to previous reports, we show that ACC deaminase genes are predominantly vertically inherited in various bacterial and fungal classes. Still, results suggest a considerable degree of horizontal gene transfer events, including interkingdom transfer events. A model for ACC deaminase origin and evolution is also proposed. This study also confirms the previous reports suggesting that the Lrp-like regulatory protein AcdR is a common mechanism regulating ACC deaminase expression in Proteobacteria, however, we also show that other regulatory mechanisms may be present in some Proteobacteria and other bacterial phyla. In this study we provide a more complete view of the role for ACC deaminase than was previously available. The results show that ACC deaminase may not only be related to plant growth promotion abilities, but may also play multiple roles in microorganism's developmental processes. Hence, exploring the origin and functioning of this enzyme may be the key in a variety of important agricultural and biotechnological applications. PMID:24905353

  2. Minimal impact of age and housing temperature on the metabolic phenotype of Acc2-/- mice.

    PubMed

    Brandon, Amanda E; Stuart, Ella; Leslie, Simon J; Hoehn, Kyle L; James, David E; Kraegen, Edward W; Turner, Nigel; Cooney, Gregory J

    2016-03-01

    An important regulator of fatty acid oxidation (FAO) is the allosteric inhibition of CPT-1 by malonyl-CoA produced by the enzyme acetyl-CoA carboxylase 2 (ACC2). Initial studies suggested that deletion of Acc2 (Acacb) increased fat oxidation and reduced adipose tissue mass but in an independently generated strain of Acc2 knockout mice we observed increased whole-body and skeletal muscle FAO and a compensatory increase in muscle glycogen stores without changes in glucose tolerance, energy expenditure or fat mass in young mice (12-16 weeks). The aim of the present study was to determine whether there was any effect of age or housing at thermoneutrality (29 °C; which reduces total energy expenditure) on the phenotype of Acc2 knockout mice. At 42-54 weeks of age, male WT and Acc2(-/-) mice had similar body weight, fat mass, muscle triglyceride content and glucose tolerance. Consistent with younger Acc2(-/-) mice, aged Acc2(-/-) mice showed increased whole-body FAO (24 h average respiratory exchange ratio=0.95±0.02 and 0.92±0.02 for WT and Acc2(-/-) mice respectively, P<0.05) and skeletal muscle glycogen content (+60%, P<0.05) without any detectable change in whole-body energy expenditure. Hyperinsulinaemic-euglycaemic clamp studies revealed no difference in insulin action between groups with similar glucose infusion rates and tissue glucose uptake. Housing Acc2(-/-) mice at 29 °C did not alter body composition, glucose tolerance or the effects of fat feeding compared with WT mice. These results confirm that manipulation of Acc2 may alter FAO in mice, but this has little impact on body composition or insulin action. PMID:26668208

  3. Monoterpene synthases from common sage (Salvia officinalis)

    DOEpatents

    Croteau, Rodney Bruce; Wise, Mitchell Lynn; Katahira, Eva Joy; Savage, Thomas Jonathan

    1999-01-01

    cDNAs encoding (+)-bornyl diphosphate synthase, 1,8-cineole synthase and (+)-sabinene synthase from common sage (Salvia officinalis) have been isolated and sequenced, and the corresponding amino acid sequences has been determined. Accordingly, isolated DNA sequences (SEQ ID No:1; SEQ ID No:3 and SEQ ID No:5) are provided which code for the expression of (+)-bornyl diphosphate synthase (SEQ ID No:2), 1,8-cineole synthase (SEQ ID No:4) and (+)-sabinene synthase SEQ ID No:6), respectively, from sage (Salvia officinalis). In other aspects, replicable recombinant cloning vehicles are provided which code for (+)-bornyl diphosphate synthase, 1,8-cineole synthase or (+)-sabinene synthase, or for a base sequence sufficiently complementary to at least a portion of (+)-bornyl diphosphate synthase, 1,8-cineole synthase or (+)-sabinene 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 (+)-bornyl diphosphate synthase, 1,8-cineole synthase or (+)-sabinene synthase. Thus, systems and methods are provided for the recombinant expression of the aforementioned recombinant monoterpene synthases that may be used to facilitate their production, isolation and purification in significant amounts. Recombinant (+)-bornyl diphosphate synthase, 1,8-cineole synthase and (+)-sabinene synthase may be used to obtain expression or enhanced expression of (+)-bornyl diphosphate synthase, 1,8-cineole synthase and (+)-sabinene synthase in plants in order to enhance the production of monoterpenoids, or may be otherwise employed for the regulation or expression of (+)-bornyl diphosphate synthase, 1,8-cineole synthase and (+)-sabinene synthase, or the production of their products.

  4. New synthetic AICAR derivatives with enhanced AMPK and ACC activation.

    PubMed

    Scudiero, Olga; Nigro, Ersilia; Monaco, Maria Ludovica; Oliviero, Giorgia; Polito, Rita; Borbone, Nicola; D'Errico, Stefano; Mayol, Luciano; Daniele, Aurora; Piccialli, Gennaro

    2016-10-01

    5-Aminoimidazole-4-carboxamide riboside (AICAR) has an important role in the regulation of the cellular metabolism showing a broad spectrum of therapeutic activities against different metabolic processes. Due to these proven AICAR properties, we have designed, synthesized and tested the biological activity of two ribose-modified AICAR derivatives, named A3 and A4, in comparison to native AICAR and its 5'-phosphorylated counterpart ZMP. Our findings have shown that A3 and A4 derivatives induce the phosphorylation of 5'-AMP activated protein kinase α (AMPKα), which leads to the inhibition of acetyl-CoA carboxylase (ACC), and down-regulate the activity of the extracellular signal-regulated kinases (ERK1/2). Cytotoxicity tests demonstrated that A3 and A4 do not significantly reduce cell viability up to 24 h. Taken together our results indicate that A3 and A4 have a comparable activity to AICAR and ZMP at 0.5 and 1 mM suggesting their potential use in future pharmacological strategies relating to metabolic diseases. PMID:26446934

  5. Astronomical Image Compression Techniques Based on ACC and KLT Coder

    NASA Astrophysics Data System (ADS)

    Schindler, J.; Páta, P.; Klíma, M.; Fliegel, K.

    This paper deals with a compression of image data in applications in astronomy. Astronomical images have typical specific properties -- high grayscale bit depth, size, noise occurrence and special processing algorithms. They belong to the class of scientific images. Their processing and compression is quite different from the classical approach of multimedia image processing. The database of images from BOOTES (Burst Observer and Optical Transient Exploring System) has been chosen as a source of the testing signal. BOOTES is a Czech-Spanish robotic telescope for observing AGN (active galactic nuclei) and the optical transient of GRB (gamma ray bursts) searching. This paper discusses an approach based on an analysis of statistical properties of image data. A comparison of two irrelevancy reduction methods is presented from a scientific (astrometric and photometric) point of view. The first method is based on a statistical approach, using the Karhunen-Loève transform (KLT) with uniform quantization in the spectral domain. The second technique is derived from wavelet decomposition with adaptive selection of used prediction coefficients. Finally, the comparison of three redundancy reduction methods is discussed. Multimedia format JPEG2000 and HCOMPRESS, designed especially for astronomical images, are compared with the new Astronomical Context Coder (ACC) coder based on adaptive median regression.

  6. 1-aminocyclopropane-1-carboxylic acid (ACC) in plants: more than just the precursor of ethylene!

    PubMed Central

    Van de Poel, Bram; Van Der Straeten, Dominique

    2014-01-01

    Ethylene is a simple two carbon atom molecule with profound effects on plants. There are quite a few review papers covering all aspects of ethylene biology in plants, including its biosynthesis, signaling and physiology. This is merely a logical consequence of the fascinating and pleiotropic nature of this gaseous plant hormone. Its biochemical precursor, 1-aminocyclopropane-1-carboxylic acid (ACC) is also a fairly simple molecule, but perhaps its role in plant biology is seriously underestimated. This triangularly shaped amino acid has many more features than just being the precursor of the lead-role player ethylene. For example, ACC can be conjugated to three different derivatives, but their biological role remains vague. ACC can also be metabolized by bacteria using ACC-deaminase, favoring plant growth and lowering stress susceptibility. ACC is also subjected to a sophisticated transport mechanism to ensure local and long-distance ethylene responses. Last but not least, there are now a few exciting studies where ACC has been reported to function as a signal itself, independently from ethylene. This review puts ACC in the spotlight, not to give it the lead-role, but to create a picture of the stunning co-production of the hormone and its precursor. PMID:25426135

  7. OpenARC: Extensible OpenACC Compiler Framework for Directive-Based Accelerator Programming Study

    SciTech Connect

    Lee, Seyong; Vetter, Jeffrey S

    2014-01-01

    Directive-based, accelerator programming models such as OpenACC have arisen as an alternative solution to program emerging Scalable Heterogeneous Computing (SHC) platforms. However, the increased complexity in the SHC systems incurs several challenges in terms of portability and productivity. This paper presents an open-sourced OpenACC compiler, called OpenARC, which serves as an extensible research framework to address those issues in the directive-based accelerator programming. This paper explains important design strategies and key compiler transformation techniques needed to implement the reference OpenACC compiler. Moreover, this paper demonstrates the efficacy of OpenARC as a research framework for directive-based programming study, by proposing and implementing OpenACC extensions in the OpenARC framework to 1) support hybrid programming of the unified memory and separate memory and 2) exploit architecture-specific features in an abstract manner. Porting thirteen standard OpenACC programs and three extended OpenACC programs to CUDA GPUs shows that OpenARC performs similarly to a commercial OpenACC compiler, while it serves as a high-level research framework.

  8. Report of the American College of Cardiology (ACC) Scientific Sessions 2016, Chicago.

    PubMed

    Mano, Toshiaki; Yamamoto, Kazuhiro

    2016-05-25

    The 65(th)Annual Scientific Sessions of the American College of Cardiology (ACC) were held at McCormick Place, Chicago, from April 2-4, 2016. The ACC Scientific Sessions are one of the 2 major scientific cardiology meetings in the USA and one of the major scientific meetings of cardiology in the world. It had an attendance of 18,769 and over 2,000 oral and poster abstracts, including 8 late-breaking clinical trials. This report presents the key presentations and the highlights from the ACC Scientific Sessions 2016 in Chicago. (Circ J 2016; 80: 1308-1313). PMID:27151567

  9. Report of the American College of Cardiology (ACC) Scientific Sessions 2015, San Diego.

    PubMed

    Murohara, Toyoaki

    2015-01-01

    The 64th Annual Scientific Sessions and Exposition of the American College of Cardiology (ACC) were held at the San Diego Convention Center from March 14-16, 2015. The ACC Scientific Sessions are 1 of 2 major scientific cardiology meetings in the United States, with nearly 20,000 attendees, including 15,000 cardiovascular professionals. There were over 2,100 oral and poster abstracts, and more than 15 late-breaking clinical trials (LBCTs) abstructs. This report presents the highlights and several key presentations, especially the LBCTs, from the ACC Scientific Sessions 2015. I hope this review will help cardiologists update to the latest information. PMID:25959559

  10. Technology Awareness Workshop on Active Combustion Control (ACC) in Propulsion Systems: JANNAF Combustion Subcommittee Workshop

    NASA Technical Reports Server (NTRS)

    Fry, Ronald S. (Editor); Gannaway, Mary T. (Editor)

    1997-01-01

    A JANNAF Combustion Subcommittee Technology Awareness Seminar on Active Combustion Control (ACC) in Propulsion Systems' was held 12 November 1997 at the NASA Lewis Research Center (LeRC), Cleveland, Ohio. The objectives of the seminar were: 1) Define the need and potential of ACC to meet future requirements for gas turbines and ramjets; 2) Explain general principles of ACC and discuss recent successes to suppress combustion instabilities, increase combustion efficiency, reduce emission, and extend flammability limits; 3) Identify R&D barriers/needs for practical implementation of ACC; 4) Explore potential for improving coordination of future R&D activities funded by various government agencies. Over 40 individuals representing senior management from over 20 industry and government organizations participated. This document summarizes the presentations and findings of this seminar.

  11. IMPACC: A Tightly Integrated MPI+OpenACC Framework Exploiting Shared Memory Parallelism

    SciTech Connect

    Lee, Seyong; Vetter, Jeffrey S

    2016-01-01

    We propose IMPACC, an MPI+OpenACC framework for heterogeneous accelerator clusters. IMPACC tightly integrates MPI and OpenACC, while exploiting the shared memory parallelism in the target system. IMPACC dynamically adapts the input MPI+OpenACC applications on the target heterogeneous accelerator clusters to fully exploit target system-specific features. IMPACC provides the programmers with the unified virtual address space, automatic NUMA-friendly task-device mapping, efficient integrated communication routines, seamless streamlining of asynchronous executions, and transparent memory sharing. We have implemented IMPACC and evaluated its performance using three heterogeneous accelerator systems, including Titan supercomputer. Results show that IMPACC can achieve easier programming, higher performance, and better scalability than the current MPI+OpenACC model.

  12. OpenACC programs of the Swendsen-Wang multi-cluster spin flip algorithm

    NASA Astrophysics Data System (ADS)

    Komura, Yukihiro

    2015-12-01

    We present sample OpenACC programs of the Swendsen-Wang multi-cluster spin flip algorithm. OpenACC is a directive-based programming model for accelerators without requiring modification to the underlying CPU code itself. In this paper, we deal with the classical spin models as with the sample CUDA programs (Komura and Okabe, 2014), that is, two-dimensional (2D) Ising model, three-dimensional (3D) Ising model, 2D Potts model, 3D Potts model, 2D XY model and 3D XY model. We explain the details of sample OpenACC programs and compare the performance of the present OpenACC implementations with that of the CUDA implementations for the 2D and 3D Ising models and the 2D and 3D XY models.

  13. Effectiveness of rhizobacteria containing ACC deaminase for growth promotion of peas (Pisum sativum) under drought conditions.

    PubMed

    Zahir, Z A; Munir, A; Asghar, H N; Shaharoona, B; Arshad, M

    2008-05-01

    A series of experiments were conducted to assess the effectiveness of rhizobacteria containing 1-aminocyclopropane- 1-carboxylate (ACC) deaminase for growth promotion of peas under drought conditions. Ten rhizobacteria isolated from the rhizosphere of different crops (peas, wheat, and maize) were screened for their growth promoting ability in peas under axenic condition. Three rhizobacterial isolates, Pseudomonas fluorescens biotype G (ACC-5), P. fluorescens (ACC-14), and P. putida biotype A (Q-7), were selected for pot trial on the basis of their source, ACC deaminase activity, root colonization, and growth promoting activity under axenic conditions. Inoculated and uninoculated (control) seeds of pea cultivar 2000 were sown in pots (4 seeds/pot) at different soil moisture levels (25, 50, 75, and 100% of field capacity). Results revealed that decreasing the soil moisture levels from 100 to 25% of field capacity significantly decreased the growth of peas. However, inoculation of peas with rhizobacteria containing ACC deaminase significantly decreased the "drought stress imposed effects" on growth of peas, although with variable efficacy at different moisture levels. At the lowest soil moisture level (25% field capacity), rhizobacterial isolate Pseudomonas fluorescens biotype G (ACC-5) was found to be more promising compared with the other isolates, as it caused maximum increases in fresh weight, dry weight, root length, shoot length, number of leaves per plant, and water use efficiency on fresh and dry weight basis (45, 150, 92, 45, 140, 46, and 147%, respectively) compared with respective uninoculated controls. It is highly likely that rhizobacteria containing ACC deaminase might have decreased the drought-stress induced ethylene in inoculated plants, which resulted in better growth of plants even at low moisture levels. Therefore, inoculation with rhizobacteria containing ACC deaminase could be helpful in eliminating the inhibitory effects of drought stress on the

  14. Mechanisms of placebo analgesia: rACC recruitment of a subcortical antinociceptive network.

    PubMed

    Bingel, U; Lorenz, J; Schoell, E; Weiller, C; Büchel, C

    2006-01-01

    Placebo analgesia is one of the most striking examples of the cognitive modulation of pain perception and the underlying mechanisms are finally beginning to be understood. According to pharmacological studies, the endogenous opioid system is essential for placebo analgesia. Recent functional imaging data provides evidence that the rostral anterior cingulate cortex (rACC) represents a crucial cortical area for this type of endogenous pain control. We therefore hypothesized that placebo analgesia recruits other brain areas outside the rACC and that interactions of the rACC with these brain areas mediate opioid-dependent endogenous antinociception as part of a top-down mechanism. Nineteen healthy subjects received and rated painful laser stimuli to the dorsum of both hands, one of them treated with a fake analgesic cream (placebo). Painful stimulation was preceded by an auditory cue, indicating the side of the next laser stimulation. BOLD-responses to the painful laser-stimulation during the placebo and no-placebo condition were assessed using event-related fMRI. After having confirmed placebo related activity in the rACC, a connectivity analysis identified placebo dependent contributions of rACC activity with bilateral amygdalae and the periaqueductal gray (PAG). This finding supports the view that placebo analgesia depends on the enhanced functional connectivity of the rACC with subcortical brain structures that are crucial for conditioned learning and descending inhibition of nociception. PMID:16364549

  15. Structure of the Cellulose Synthase Complex of Gluconacetobacter hansenii at 23.4 Å Resolution

    PubMed Central

    Du, Juan; Vepachedu, Venkata; Cho, Sung Hyun; Kumar, Manish; Nixon, B. Tracy

    2016-01-01

    Bacterial crystalline cellulose is used in biomedical and industrial applications, but the molecular mechanisms of synthesis are unclear. Unlike most bacteria, which make non-crystalline cellulose, Gluconacetobacter hansenii extrudes profuse amounts of crystalline cellulose. Its cellulose synthase (AcsA) exists as a complex with accessory protein AcsB, forming a 'terminal complex' (TC) that has been visualized by freeze-fracture TEM at the base of ribbons of crystalline cellulose. The catalytic AcsAB complex is embedded in the cytoplasmic membrane. The C-terminal portion of AcsC is predicted to form a translocation channel in the outer membrane, with the rest of AcsC possibly interacting with AcsD in the periplasm. It is thus believed that synthesis from an organized array of TCs coordinated with extrusion by AcsC and AcsD enable this bacterium to make crystalline cellulose. The only structural data that exist for this system are the above mentioned freeze-fracture TEM images, fluorescence microscopy images revealing that TCs align in a row, a crystal structure of AcsD bound to cellopentaose, and a crystal structure of PilZ domain of AcsA. Here we advance our understanding of the structural basis for crystalline cellulose production by bacterial cellulose synthase by determining a negative stain structure resolved to 23.4 Å for highly purified AcsAB complex that catalyzed incorporation of UDP-glucose into β-1,4-glucan chains, and responded to the presence of allosteric activator cyclic diguanylate. Although the AcsAB complex was functional in vitro, the synthesized cellulose was not visible in TEM. The negative stain structure revealed that AcsAB is very similar to that of the BcsAB synthase of Rhodobacter sphaeroides, a non-crystalline cellulose producing bacterium. The results indicate that the crystalline cellulose producing and non-crystalline cellulose producing bacteria share conserved catalytic and membrane translocation components, and support the

  16. Structure of the cellulose synthase complex of Gluconacetobacter hansenii at 23.4 Å resolution

    DOE PAGESBeta

    Du, Juan; Vepachedu, Venkata; Cho, Sung Hyun; Kumar, Manish; Nixon, B. Tracy; Lai, Hsin -Chih

    2016-05-23

    Bacterial crystalline cellulose is used in biomedical and industrial applications, but the molecular mechanisms of synthesis are unclear. Unlike most bacteria, which make non-crystalline cellulose, Gluconacetobacter hansenii extrudes profuse amounts of crystalline cellulose. Its cellulose synthase (AcsA) exists as a complex with accessory protein AcsB, forming a 'terminal complex' (TC) that has been visualized by freeze-fracture TEM at the base of ribbons of crystalline cellulose. The catalytic AcsAB complex is embedded in the cytoplasmic membrane. The C-terminal portion of AcsC is predicted to form a translocation channel in the outer membrane, with the rest of AcsC possibly interacting with AcsDmore » in the periplasm. It is thus believed that synthesis from an organized array of TCs coordinated with extrusion by AcsC and AcsD enable this bacterium to make crystalline cellulose. The only structural data that exist for this system are the above mentioned freeze-fracture TEM images, fluorescence microscopy images revealing that TCs align in a row, a crystal structure of AcsD bound to cellopentaose, and a crystal structure of PilZ domain of AcsA. Here we advance our understanding of the structural basis for crystalline cellulose production by bacterial cellulose synthase by determining a negative stain structure resolved to 23.4 angstrom for highly purified AcsAB complex that catalyzed incorporation of UDP-glucose into β-1,4-glucan chains, and responded to the presence of allosteric activator cyclic diguanylate. Although the AcsAB complex was functional in vitro, the synthesized cellulose was not visible in TEM. The negative stain structure revealed that AcsAB is very similar to that of the BcsAB synthase of Rhodobacter sphaeroides, a non-crystalline cellulose producing bacterium. Furthermore, the results indicate that the crystalline cellulose producing and non-crystalline cellulose producing bacteria share conserved catalytic and membrane translocation

  17. Structure of the Cellulose Synthase Complex of Gluconacetobacter hansenii at 23.4 Å Resolution.

    PubMed

    Du, Juan; Vepachedu, Venkata; Cho, Sung Hyun; Kumar, Manish; Nixon, B Tracy

    2016-01-01

    Bacterial crystalline cellulose is used in biomedical and industrial applications, but the molecular mechanisms of synthesis are unclear. Unlike most bacteria, which make non-crystalline cellulose, Gluconacetobacter hansenii extrudes profuse amounts of crystalline cellulose. Its cellulose synthase (AcsA) exists as a complex with accessory protein AcsB, forming a 'terminal complex' (TC) that has been visualized by freeze-fracture TEM at the base of ribbons of crystalline cellulose. The catalytic AcsAB complex is embedded in the cytoplasmic membrane. The C-terminal portion of AcsC is predicted to form a translocation channel in the outer membrane, with the rest of AcsC possibly interacting with AcsD in the periplasm. It is thus believed that synthesis from an organized array of TCs coordinated with extrusion by AcsC and AcsD enable this bacterium to make crystalline cellulose. The only structural data that exist for this system are the above mentioned freeze-fracture TEM images, fluorescence microscopy images revealing that TCs align in a row, a crystal structure of AcsD bound to cellopentaose, and a crystal structure of PilZ domain of AcsA. Here we advance our understanding of the structural basis for crystalline cellulose production by bacterial cellulose synthase by determining a negative stain structure resolved to 23.4 Å for highly purified AcsAB complex that catalyzed incorporation of UDP-glucose into β-1,4-glucan chains, and responded to the presence of allosteric activator cyclic diguanylate. Although the AcsAB complex was functional in vitro, the synthesized cellulose was not visible in TEM. The negative stain structure revealed that AcsAB is very similar to that of the BcsAB synthase of Rhodobacter sphaeroides, a non-crystalline cellulose producing bacterium. The results indicate that the crystalline cellulose producing and non-crystalline cellulose producing bacteria share conserved catalytic and membrane translocation components, and support the

  18. Thymidylate synthase inhibitors.

    PubMed

    Danenberg, P V; Malli, H; Swenson, S

    1999-12-01

    Thymidylate synthase (TS) is a critical enzyme for DNA replication and cell growth because it is the only de novo source of thymine nucleotide precursors for DNA synthesis. TS is the primary target of 5-fluorouracil (5-FU), which has been used for cancer treatment for more than 40 years. However, dissatisfaction with the overall activity of 5-FU against the major cancers, and the recognition that TS still remains an attractive target for anticancer drugs because of its central position in the pathway of DNA synthesis, led to a search for new inhibitors of TS structurally analogous to 5,10-methylenetetrahydrofolate, the second substrate of TS. TS inhibitory antifolates developed to date that are in various stages of clinical evaluation are ZD 1694 and ZD9331 (Astra-Zeneca, London, UK), (Eli Lilly, Indianapolis, IN), LY231514 (BW1843U89 (Glaxo-Wellcome, Research Triangle Park, NC), and AG337 and AG331 (Agouron, La Jolla, CA). Although each of these compounds has TS as its major intracellular site of action, they differ in propensity for polyglutamylation and for transport by the reduced folate carrier. LY231514 also has secondary target enzymes. As a result, each compound is likely to have a different spectrum of antitumor activity and toxicity. This review will summarize the development and properties of this new class of TS inhibitors. PMID:10606255

  19. ACS Quicklook PDF products

    NASA Astrophysics Data System (ADS)

    Suchkov, Anatoly

    1999-12-01

    This report details the features of the ACS quicklook PDF products produced by the HST data pipeline. The requirements closely follow the design of paper products recommended by the Data Quality Committee, with appropriate changes required to fully support ACS.

  20. OpenACC to FPGA: A Framework for Directive-based High-Performance Reconfigurable Computing

    SciTech Connect

    Lee, Seyong; Vetter, Jeffrey S

    2016-01-01

    This paper presents a directive-based, high-level programming framework for high-performance reconfigurable computing. It takes a standard, portable OpenACC C program as input and generates a hardware configuration file for execution on FPGAs. We implemented this prototype system using our open-source OpenARC compiler; it performs source-to-source translation and optimization of the input OpenACC program into an OpenCL code, which is further compiled into a FPGA program by the backend Altera Offline OpenCL compiler. Internally, the design of OpenARC uses a high- level intermediate representation that separates concerns of program representation from underlying architectures, which facilitates portability of OpenARC. In fact, this design allowed us to create the OpenACC-to-FPGA translation framework with minimal extensions to our existing system. In addition, we show that our proposed FPGA-specific compiler optimizations and novel OpenACC pragma extensions assist the compiler in generating more efficient FPGA hardware configuration files. Our empirical evaluation on an Altera Stratix V FPGA with eight OpenACC benchmarks demonstrate the benefits of our strategy. To demonstrate the portability of OpenARC, we show results for the same benchmarks executing on other heterogeneous platforms, including NVIDIA GPUs, AMD GPUs, and Intel Xeon Phis. This initial evidence helps support the goal of using a directive-based, high-level programming strategy for performance portability across heterogeneous HPC architectures.

  1. Positive coping styles and perigenual ACC volume: two related mechanisms for conferring resilience?

    PubMed

    Holz, Nathalie E; Boecker, Regina; Jennen-Steinmetz, Christine; Buchmann, Arlette F; Blomeyer, Dorothea; Baumeister, Sarah; Plichta, Michael M; Esser, Günter; Schmidt, Martin; Meyer-Lindenberg, Andreas; Banaschewski, Tobias; Brandeis, Daniel; Laucht, Manfred

    2016-05-01

    Stress exposure has been linked to increased rates of depression and anxiety in adults, particularly in females, and has been associated with maladaptive changes in the anterior cingulate cortex (ACC), which is an important brain structure involved in internalizing disorders. Coping styles are important mediators of the stress reaction by establishing homeostasis, and may thus confer resilience to stress-related psychopathology. Anatomical scans were acquired in 181 healthy participants at age 25 years. Positive coping styles were determined using a self-report questionnaire (German Stress Coping Questionnaire, SVF78) at age 22 years. Adult anxiety and depression symptoms were assessed at ages 22, 23 and 25 years with the Young Adult Self-Report. Information on previous internalizing diagnoses was obtained by diagnostic interview (2-19 years). Positive coping styles were associated with increased ACC volume. ACC volume and positive coping styles predicted anxiety and depression in a sex-dependent manner with increased positive coping and ACC volume being related to lower levels of psychopathology in females, but not in males. These results remained significant when controlled for previous internalizing diagnoses. These findings indicate that positive coping styles and ACC volume are two linked mechanisms, which may serve as protective factors against internalizing disorders. PMID:26743466

  2. Atypical expression of mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase in subcutaneous adipose tissue of male rats.

    PubMed

    Thumelin, S; Kohl, C; Girard, J; Pégorier, J P

    1999-06-01

    The mRNAs encoding mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase (mtHMG-CoA synthase), the rate limiting enzyme in ketone body production, are highly expressed in subcutaneous (SC) and, to a lesser extent, in peri-epididymal (PE) rat adipose tissues. This atypical mtHMG-CoA synthase gene expression is dependent on the age (from 9 weeks of age) and sex (higher in male than in female) of the rats. In contrast, the expression of mtHMG-CoA synthase in SC adipose deposit is independent of the nutritional state (fed versus starved) or of the thermic environment (24 degrees C versus 4 degrees C). The expression of mtHMG-CoA synthase is suppressed in SC fat pads of castrated male rats whereas treatment of castrated rats with testosterone restores a normal level of expression. Moreover, testosterone injection induces the expression mtHMG-CoA synthase in SC adipose tissue of age-matched females. The presence of the mtHMG-CoA synthase immunoreactive protein confers to mitochondria isolated from SC adipose deposits, the capacity to produce ketone bodies at a rate similar to that found in liver mitochondria (SC = 13.7 +/- 0.7, liver = 16.4 +/- 1.4 nmol/min/mg prot). mtHMG-CoA synthase is expressed in the stromal vascular fraction (SVF) whatever the adipose deposit considered. While acetyl-CoA carboxylase (ACC) is only expressed in mature adipocytes, the other lipogenic enzymes, fatty acid synthase (FAS) and citrate cleavage enzyme (CCE), are expressed both in SVF cells and mature adipocytes. The expression of lipogenic enzyme genes is markedly reduced in adipocytes but not in SVF cells isolated from 48-h starved male rats. When SVF is subfractionated, mtHMG-CoA synthase mRNAs are mainly recovered in two fractions containing poorly digested structures such as microcapillaries whereas the lowest expression is found in the pre-adipocyte fraction. Interestingly, FAS and CCE mRNAs co-segregate with mtHMG-CoA synthase mRNA. The possible physiological relevance of such

  3. Kinetic and Chemical Mechanisms of Homocitrate Synthase from Thermus thermophilus*

    PubMed Central

    Kumar, Vidya Prasanna; West, Ann H.; Cook, Paul F.

    2011-01-01

    The homocitrate synthase from Thermus thermophilus (TtHCS) is a metal-activated enzyme with either Mg2+ or Mn2+ capable of serving as the divalent cation. The enzyme exhibits a sequential kinetic mechanism. The mechanism is steady state ordered with α-ketoglutarate (α-Kg) binding prior to acetyl-CoA (AcCoA) with Mn2+, whereas it is steady state random with Mg2+, suggesting a difference in the competence of the E·Mn·α-Kg·AcCoA and E·Mg·α-Kg·AcCoA complexes. The mechanism is supported by product and dead-end inhibition studies. The primary isotope effect obtained with deuterioacetylCoA (AcCoA-d3) in the presence of Mg2+ is unity (value 1.0) at low concentrations of AcCoA, whereas it is 2 at high concentrations of AcCoA. Data suggest the presence of a slow conformational change induced by binding of AcCoA that accompanies deprotonation of the methyl group of AcCoA. The solvent kinetic deuterium isotope effect is also unity at low AcCoA, but is 1.7 at high AcCoA, consistent with the proposed slow conformational change. The maximum rate is pH independent with either Mg2+ or Mn2+ as the divalent metal ion, whereas V/Kα-Kg (with Mn2+) decreases at low and high pH giving pK values of about 6.5 and 8.0. Lysine is a competitive inhibitor that binds to the active site of TtHCS, and shares some of the same binding determinants as α-Kg. Lysine binding exhibits negative cooperativity, indicating cross-talk between the two monomers of the TtHCS dimer. Data are discussed in terms of the overall mechanism of TtHCS. PMID:21733842

  4. Precipitation of ACC in liposomes-a model for biomineralization in confined volumes

    SciTech Connect

    Tester, Chantel C; Wu, Ching-Hsuan; Weigand, Steven; Joester, Derk

    2013-01-10

    Biomineralizing organisms frequently precipitate minerals in small phospholipid bilayer-delineated compartments. We have established an in vitro model system to investigate the effect of confinement in attoliter to femtoliter volumes on the precipitation of calcium carbonate. In particular, we analyze the growth and stabilization of liposome-encapsulated amorphous calcium carbonate (ACC) nanoparticles using a combination of in situ techniques, cryo-transmission electron microscopy (Cryo-TEM), and small angle X-ray scattering (SAXS). Herein, we discuss ACC nanoparticle growth rate as a function of liposome size, carbon dioxide flux across the liposome membrane, pH, and osmotic pressure. Based on these experiments, we argue that the stabilization of ACC nanoparticles in liposomes is a consequence of a low nucleation rate (high activation barrier) of crystalline polymorphs of calcium carbonate.

  5. A feasibility study on porting the community land model onto accelerators using OpenACC

    DOE PAGESBeta

    Wang, Dali; Wu, Wei; Winkler, Frank; Ding, Wei; Hernandez, Oscar R.

    2014-01-01

    As environmental models (such as Accelerated Climate Model for Energy (ACME), Parallel Reactive Flow and Transport Model (PFLOTRAN), Arctic Terrestrial Simulator (ATS), etc.) became more and more complicated, we are facing enormous challenges regarding to porting those applications onto hybrid computing architecture. OpenACC appears as a very promising technology, therefore, we have conducted a feasibility analysis on porting the Community Land Model (CLM), a terrestrial ecosystem model within the Community Earth System Models (CESM)). Specifically, we used automatic function testing platform to extract a small computing kernel out of CLM, then we apply this kernel into the actually CLM dataflowmore » procedure, and investigate the strategy of data parallelization and the benefit of data movement provided by current implementation of OpenACC. Even it is a non-intensive kernel, on a single 16-core computing node, the performance (based on the actual computation time using one GPU) of OpenACC implementation is 2.3 time faster than that of OpenMP implementation using single OpenMP thread, but it is 2.8 times slower than the performance of OpenMP implementation using 16 threads. On multiple nodes, MPI_OpenACC implementation demonstrated very good scalability on up to 128 GPUs on 128 computing nodes. This study also provides useful information for us to look into the potential benefits of “deep copy” capability and “routine” feature of OpenACC standards. In conclusion, we believe that our experience on the environmental model, CLM, can be beneficial to many other scientific research programs who are interested to porting their large scale scientific code using OpenACC onto high-end computers, empowered by hybrid computing architecture.« less

  6. A feasibility study on porting the community land model onto accelerators using OpenACC

    SciTech Connect

    Wang, Dali; Wu, Wei; Winkler, Frank; Ding, Wei; Hernandez, Oscar R.

    2014-01-01

    As environmental models (such as Accelerated Climate Model for Energy (ACME), Parallel Reactive Flow and Transport Model (PFLOTRAN), Arctic Terrestrial Simulator (ATS), etc.) became more and more complicated, we are facing enormous challenges regarding to porting those applications onto hybrid computing architecture. OpenACC appears as a very promising technology, therefore, we have conducted a feasibility analysis on porting the Community Land Model (CLM), a terrestrial ecosystem model within the Community Earth System Models (CESM)). Specifically, we used automatic function testing platform to extract a small computing kernel out of CLM, then we apply this kernel into the actually CLM dataflow procedure, and investigate the strategy of data parallelization and the benefit of data movement provided by current implementation of OpenACC. Even it is a non-intensive kernel, on a single 16-core computing node, the performance (based on the actual computation time using one GPU) of OpenACC implementation is 2.3 time faster than that of OpenMP implementation using single OpenMP thread, but it is 2.8 times slower than the performance of OpenMP implementation using 16 threads. On multiple nodes, MPI_OpenACC implementation demonstrated very good scalability on up to 128 GPUs on 128 computing nodes. This study also provides useful information for us to look into the potential benefits of “deep copy” capability and “routine” feature of OpenACC standards. In conclusion, we believe that our experience on the environmental model, CLM, can be beneficial to many other scientific research programs who are interested to porting their large scale scientific code using OpenACC onto high-end computers, empowered by hybrid computing architecture.

  7. Frontal and rostral anterior cingulate (rACC) theta EEG in depression: implications for treatment outcome?

    PubMed

    Arns, Martijn; Etkin, Amit; Hegerl, Ulrich; Williams, Leanne M; DeBattista, Charles; Palmer, Donna M; Fitzgerald, Paul B; Harris, Anthony; deBeuss, Roger; Gordon, Evian

    2015-08-01

    In major depressive disorder (MDD), elevated theta current density in the rostral anterior cingulate (rACC), as estimated by source localization of scalp-recorded electroencenphalogram (EEG), has been associated with response to antidepressant treatments, whereas elevated frontal theta has been linked to non-response. This study used source localization to attempt to integrate these apparently opposite results and test, whether antidepressant response is associated with elevated rACC theta and non-response with elevated frontal theta and whether theta activity is a differential predictor of response to different types of commonly used antidepressants. In the international Study to Predict Optimized Treatment in Depression (iSPOT-D), a multi-center, international, randomized, prospective practical trial, 1008 MDD participants were randomized to escitalopram, sertraline or venlafaxine-XR. The study also recruited 336 healthy controls. Treatment response and remission were established after eight weeks using the 17-item Hamilton Rating Scale for Depression (HRSD17). The resting-state EEG was assessed at baseline with eyes closed and source localization (eLORETA) was employed to extract theta from the rACC and frontal cortex. Patients with MDD had elevated theta in both frontal cortex and rACC, with small effect sizes. High frontal and rACC theta were associated with treatment non-response, but not with non-remission, and this effect was most pronounced in a subgroup with previous treatment failures. Low theta in frontal cortex and rACC are found in responders to antidepressant treatments with a small effect size. Future studies should investigate in more detail the role of previous treatment (failure) in the association between theta and treatment outcome. PMID:25936227

  8. Cloning and Structure-Function Analyses of Quinolone- and Acridone-producing Novel Type III Polyketide Synthases from Citrus microcarpa*

    PubMed Central

    Mori, Takahiro; Shimokawa, Yoshihiko; Matsui, Takashi; Kinjo, Keishi; Kato, Ryohei; Noguchi, Hiroshi; Sugio, Shigetoshi; Morita, Hiroyuki; Abe, Ikuro

    2013-01-01

    Two novel type III polyketide synthases, quinolone synthase (QNS) and acridone synthase (ACS), were cloned from Citrus microcarpa (Rutaceae). The deduced amino acid sequence of C. microcarpa QNS is unique, and it shared only 56–60% identities with C. microcarpa ACS, Medicago sativa chalcone synthase (CHS), and the previously reported Aegle marmelos QNS. In contrast to the quinolone- and acridone-producing A. marmelos QNS, C. microcarpa QNS produces 4-hydroxy-N-methylquinolone as the “single product” by the one-step condensation of N-methylanthraniloyl-CoA and malonyl-CoA. However, C. microcarpa ACS shows broad substrate specificities and produces not only acridone and quinolone but also chalcone, benzophenone, and phloroglucinol from 4-coumaroyl-CoA, benzoyl-CoA, and hexanoyl-CoA, respectively. Furthermore, the x-ray crystal structures of C. microcarpa QNS and ACS, solved at 2.47- and 2.35-Å resolutions, respectively, revealed wide active site entrances in both enzymes. The wide active site entrances thus provide sufficient space to facilitate the binding of the bulky N-methylanthraniloyl-CoA within the catalytic centers. However, the active site cavity volume of C. microcarpa ACS (760 Å3) is almost as large as that of M. sativa CHS (750 Å3), and ACS produces acridone by employing an active site cavity and catalytic machinery similar to those of CHS. In contrast, the cavity of C. microcarpa QNS (290 Å3) is significantly smaller, which makes this enzyme produce the diketide quinolone. These results as well as mutagenesis analyses provided the first structural bases for the anthranilate-derived production of the quinolone and acridone alkaloid by type III polyketide synthases. PMID:23963450

  9. An OpenACC-Based Unified Programming Model for Multi-accelerator Systems

    SciTech Connect

    Kim, Jungwon; Lee, Seyong; Vetter, Jeffrey S

    2015-01-01

    This paper proposes a novel SPMD programming model of OpenACC. Our model integrates the different granularities of parallelism from vector-level parallelism to node-level parallelism into a single, unified model based on OpenACC. It allows programmers to write programs for multiple accelerators using a uniform programming model whether they are in shared or distributed memory systems. We implement a prototype of our model and evaluate its performance with a GPU-based supercomputer using three benchmark applications.

  10. Genetics Home Reference: GM3 synthase deficiency

    MedlinePlus

    ... GM3 synthase deficiency is characterized by recurrent seizures (epilepsy) and problems with brain development. Within the first ... diagnosis or management of GM3 synthase deficiency: American Epilepsy Society: Find a Doctor Clinic for Special Children ( ...

  11. Mycocerosic acid synthase exemplifies the architecture of reducing polyketide synthases.

    PubMed

    Herbst, Dominik A; Jakob, Roman P; Zähringer, Franziska; Maier, Timm

    2016-03-24

    Polyketide synthases (PKSs) are biosynthetic factories that produce natural products with important biological and pharmacological activities. Their exceptional product diversity is encoded in a modular architecture. Modular PKSs (modPKSs) catalyse reactions colinear to the order of modules in an assembly line, whereas iterative PKSs (iPKSs) use a single module iteratively as exemplified by fungal iPKSs (fiPKSs). However, in some cases non-colinear iterative action is also observed for modPKSs modules and is controlled by the assembly line environment. PKSs feature a structural and functional separation into a condensing and a modifying region as observed for fatty acid synthases. Despite the outstanding relevance of PKSs, the detailed organization of PKSs with complete fully reducing modifying regions remains elusive. Here we report a hybrid crystal structure of Mycobacterium smegmatis mycocerosic acid synthase based on structures of its condensing and modifying regions. Mycocerosic acid synthase is a fully reducing iPKS, closely related to modPKSs, and the prototype of mycobacterial mycocerosic acid synthase-like PKSs. It is involved in the biosynthesis of C20-C28 branched-chain fatty acids, which are important virulence factors of mycobacteria. Our structural data reveal a dimeric linker-based organization of the modifying region and visualize dynamics and conformational coupling in PKSs. On the basis of comparative small-angle X-ray scattering, the observed modifying region architecture may be common also in modPKSs. The linker-based organization provides a rationale for the characteristic variability of PKS modules as a main contributor to product diversity. The comprehensive architectural model enables functional dissection and re-engineering of PKSs. PMID:26976449

  12. 24 CFR 969.105 - Extension of ACC upon payment of operating subsidy.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... are subject to the Consolidated ACC (see 24 CFR part 990). Accordingly, if a PHA, before submitting a..., under 24 CFR part 990, for determination of the total amount of Operating Subsidy payable under the... HOUSING AND URBAN DEVELOPMENT PHA-OWNED PROJ- ECTS-CONTINUED OPERATION AS LOW-INCOME HOUSING...

  13. Mentoring in 2 + 2 Programs: LISD/ACC 2 + 2 Articulation Project.

    ERIC Educational Resources Information Center

    Center for Occupational Research and Development, Inc., Waco, TX.

    The role of mentoring in the 2 + 2 Instrumentation and Control (I&C) articulation project between the Leander Independent School District (LISD) and Austin Community College (ACC) is discussed in this document. Following a brief history of the origin and function of the mentor, the paper explains the need for the mentoring system in the I&C…

  14. ACCE Study Tour to ISTE2011 (San Francisco, New York, Washington, Philadelphia)

    ERIC Educational Resources Information Center

    Gronn, Donna; Romeo, Geoff

    2011-01-01

    In June/July this year a group of 28 educators from across Australia travelled to the US on the 2011 ACCE ISTE Study Tour. The group comprised a very broad section of educators--primary, secondary and tertiary classroom teachers, ICT coordinators, managers, private consultants and regional office managers. The government, catholic and independent…

  15. GPER agonist G-1 decreases adrenocortical carcinoma (ACC) cell growth in vitro and in vivo

    PubMed Central

    Zolea, Fabiana; Rizza, Pietro; Avena, Paola; Malivindi, Rocco; De Luca, Arianna; Campana, Carmela; Martire, Emilia; Domanico, Francesco; Fallo, Francesco; Carpinelli, Giulia; Cerquetti, Lidia; Amendola, Donatella; Stigliano, Antonio; Pezzi, Vincenzo

    2015-01-01

    We have previously demonstrated that estrogen receptor (ER) alpha (ESR1) increases proliferation of adrenocortical carcinoma (ACC) through both an estrogen-dependent and -independent (induced by IGF-II/IGF1R pathways) manner. Then, the use of tamoxifen, a selective estrogen receptor modulator (SERM), appears effective in reducing ACC growth in vitro and in vivo. However, tamoxifen not only exerts antiestrogenic activity, but also acts as full agonist on the G protein-coupled estrogen receptor (GPER). Aim of this study was to investigate the effect of a non-steroidal GPER agonist G-1 in modulating ACC cell growth. We found that G-1 is able to exert a growth inhibitory effect on H295R cells both in vitro and, as xenograft model, in vivo. Treatment of H295R cells with G-1 induced cell cycle arrest, DNA damage and cell death by the activation of the intrinsic apoptotic mechanism. These events required sustained extracellular regulated kinase (ERK) 1/2 activation. Silencing of GPER by a specific shRNA partially reversed G-1-mediated cell growth inhibition without affecting ERK activation. These data suggest the existence of G-1 activated but GPER-independent effects that remain to be clarified. In conclusion, this study provides a rational to further study G-1 mechanism of action in order to include this drug as a treatment option to the limited therapy of ACC. PMID:26131713

  16. GPER agonist G-1 decreases adrenocortical carcinoma (ACC) cell growth in vitro and in vivo.

    PubMed

    Chimento, Adele; Sirianni, Rosa; Casaburi, Ivan; Zolea, Fabiana; Rizza, Pietro; Avena, Paola; Malivindi, Rocco; De Luca, Arianna; Campana, Carmela; Martire, Emilia; Domanico, Francesco; Fallo, Francesco; Carpinelli, Giulia; Cerquetti, Lidia; Amendola, Donatella; Stigliano, Antonio; Pezzi, Vincenzo

    2015-08-01

    We have previously demonstrated that estrogen receptor (ER) alpha (ESR1) increases proliferation of adrenocortical carcinoma (ACC) through both an estrogen-dependent and -independent (induced by IGF-II/IGF1R pathways) manner. Then, the use of tamoxifen, a selective estrogen receptor modulator (SERM), appears effective in reducing ACC growth in vitro and in vivo. However, tamoxifen not only exerts antiestrogenic activity, but also acts as full agonist on the G protein-coupled estrogen receptor (GPER). Aim of this study was to investigate the effect of a non-steroidal GPER agonist G-1 in modulating ACC cell growth. We found that G-1 is able to exert a growth inhibitory effect on H295R cells both in vitro and, as xenograft model, in vivo. Treatment of H295R cells with G-1 induced cell cycle arrest, DNA damage and cell death by the activation of the intrinsic apoptotic mechanism. These events required sustained extracellular regulated kinase (ERK) 1/2 activation. Silencing of GPER by a specific shRNA partially reversed G-1-mediated cell growth inhibition without affecting ERK activation. These data suggest the existence of G-1 activated but GPER-independent effects that remain to be clarified. In conclusion, this study provides a rational to further study G-1 mechanism of action in order to include this drug as a treatment option to the limited therapy of ACC. PMID:26131713

  17. Waste management facility accident analysis (WASTE ACC) system: software for analysis of waste management alternatives

    SciTech Connect

    Kohout, E.F.; Folga, S.; Mueller, C.; Nabelssi, B.

    1996-03-01

    This paper describes the Waste Management Facility Accident Analysis (WASTE{underscore}ACC) software, which was developed at Argonne National Laboratory (ANL) to support the US Department of Energy`s (DOE`s) Waste Management (WM) Programmatic Environmental Impact Statement (PEIS). WASTE{underscore}ACC is a decision support and database system that is compatible with Microsoft{reg_sign} Windows{trademark}. It assesses potential atmospheric releases from accidents at waste management facilities. The software provides the user with an easy-to-use tool to determine the risk-dominant accident sequences for the many possible combinations of process technologies, waste and facility types, and alternative cases described in the WM PEIS. In addition, its structure will allow additional alternative cases and assumptions to be tested as part of the future DOE programmatic decision-making process. The WASTE{underscore}ACC system demonstrates one approach to performing a generic, systemwide evaluation of accident risks at waste management facilities. The advantages of WASTE{underscore}ACC are threefold. First, the software gets waste volume and radiological profile data that were used to perform other WM PEIS-related analyses directly from the WASTE{underscore}MGMT system. Second, the system allows for a consistent analysis across all sites and waste streams, which enables decision makers to understand more fully the trade-offs among various policy options and scenarios. Third, the system is easy to operate; even complex scenario runs are completed within minutes.

  18. A Comparative Analysis of the Integration of Faith and Learning between ACSI and ACCS Accredited Schools

    ERIC Educational Resources Information Center

    Peterson, Daniel Carl

    2012-01-01

    The purpose of this descriptive quantitative study was to analyze and compare the integration of faith and learning occurring in Christian schools accredited by the Association of Christian Schools International (ACSI) and classical Christian schools accredited by the Association of Classical and Christian Schools (ACCS). ACSI represents the…

  19. National Computing Studies Summit: Open Learning Approaches to Computing Studies--An ACCE Discussion Paper

    ERIC Educational Resources Information Center

    Webb, Ian

    2008-01-01

    In 2005 the Australian Council for Computers in Education (ACCE) was successful in obtaining a grant from National Centre of Science, Information and Communication Technology and Mathematics Education for Rural and Regional Australia (SiMERR) to undertake the Computing Studies Teachers Network Rural and Regional Focus Project. The project had five…

  20. Usability of AcceSS for Web Site Accessibility. Research Report

    ERIC Educational Resources Information Center

    Hackett, Stephanie; Parmanto, Bambang

    2006-01-01

    The standard display of web pages is inadequate for users who are visually impaired. Most visually impaired people obtain information from a web page in a linear fashion via a screen reader, whereas sighted users can immediately obtain a bird's-eye view of a web page's organization and content by quickly scanning the page. AcceSS (which stands for…

  1. 24 CFR 969.107 - HUD approval of demolition or disposition before ACC expiration.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 4 2010-04-01 2010-04-01 false HUD approval of demolition or disposition before ACC expiration. 969.107 Section 969.107 Housing and Urban Development Regulations Relating to Housing and Urban Development (Continued) OFFICE OF ASSISTANT SECRETARY FOR PUBLIC AND INDIAN HOUSING, DEPARTMENT OF HOUSING AND...

  2. 24 CFR 969.107 - HUD approval of demolition or disposition before ACC expiration.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... expiration. This part is not intended to preclude or restrict the demolition or disposition of a project pursuant to HUD approval in accordance with 24 CFR part 970. Subject to the requirements of 24 CFR part 970... disposition before ACC expiration. 969.107 Section 969.107 Housing and Urban Development REGULATIONS...

  3. 24 CFR 969.107 - HUD approval of demolition or disposition before ACC expiration.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... expiration. This part is not intended to preclude or restrict the demolition or disposition of a project pursuant to HUD approval in accordance with 24 CFR part 970. Subject to the requirements of 24 CFR part 970... disposition before ACC expiration. 969.107 Section 969.107 Housing and Urban Development REGULATIONS...

  4. 24 CFR 969.107 - HUD approval of demolition or disposition before ACC expiration.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... expiration. This part is not intended to preclude or restrict the demolition or disposition of a project pursuant to HUD approval in accordance with 24 CFR part 970. Subject to the requirements of 24 CFR part 970... disposition before ACC expiration. 969.107 Section 969.107 Housing and Urban Development REGULATIONS...

  5. Sucrose Synthase: Expanding Protein Function

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sucrose synthase (SUS: EC 2.4.1.13), a key enzyme in plant sucrose catabolism, is uniquely able to mobilize sucrose into multiple pathways involved in metabolic, structural, and storage functions. Our research indicates that the biological function of SUS may extend beyond its catalytic activity. Th...

  6. Modifying the determinants of α-ketoacid substrate selectivity in mycobacterium tuberculosis α-isopropylmalate synthase.

    PubMed

    Hunter, Michael F C; Parker, Emily J

    2014-05-01

    α-Isopropylmalate synthase (IPMS) catalyses the reaction between α-ketoisovalerate and acetyl coenzyme A (AcCoA) in the first step of leucine biosynthesis. IPMS is closely related to homocitrate synthase, which catalyses the reaction between AcCoA and the unbranched α-ketoacid α-ketoglutarate. Analysis of these enzymes suggests that several differently conserved key residues are responsible for the different substrate selectivity. These residues were systematically substituted in the Mycobacterium tuberculosis IPMS, resulting in changes in substrate specificity. A variant of IPMS was constructed with a preference for the unbranched α-ketoacids α-ketobutyrate and pyruvate over the natural branched substrate α-ketoisovalerate. PMID:24613923

  7. Characterization of α-humulene synthases responsible for the production of sesquiterpenes induced by methyl jasmonate in Aquilaria cell culture.

    PubMed

    Kumeta, Yukie; Ito, Michiho

    2016-07-01

    The resinous portions of Aquilaria and Gyrinops plants are known as 'agarwood' and have a distinctive fragrance. To examine the biosynthesis of these fragrant compounds, we previously established cell cultures of Aquilaria crassna in which the production of three sesquiterpenes (α-guaiene, α-humulene, and δ-guaiene) could be induced by methyl jasmonate (MJ), and showed that cloned δ-guaiene synthase from MJ-treated cells is involved in the synthesis of these three compounds, although only very small amounts of α-humulene are produced. In the present study, cDNAs encoding α-humulene synthases were also isolated. Three putative sesquiterpene synthase clones (AcHS1-3) isolated from the MJ-treated cells had very similar amino acid sequences and shared 52 % identity with δ-guaiene synthases. The recombinant enzymes catalyzed the formation of α-humulene as a major product. Expression of transcripts of the α-humulene synthase and δ-guaiene synthase genes in cultured cells increased after treatment with MJ. These results revealed that these α-humulene and δ-guaiene synthases are involved in the synthesis of three sesquiterpenes induced by MJ treatment. PMID:27180085

  8. Isoprene synthase genes form a monophyletic clade of acyclic terpene synthases in the TPS-B terpene synthase family.

    PubMed

    Sharkey, Thomas D; Gray, Dennis W; Pell, Heather K; Breneman, Steven R; Topper, Lauren

    2013-04-01

    Many plants emit significant amounts of isoprene, which is hypothesized to help leaves tolerate short episodes of high temperature. Isoprene emission is found in all major groups of land plants including mosses, ferns, gymnosperms, and angiosperms; however, within these groups isoprene emission is variable. The patchy distribution of isoprene emission implies an evolutionary pattern characterized by many origins or many losses. To better understand the evolution of isoprene emission, we examine the phylogenetic relationships among isoprene synthase and monoterpene synthase genes in the angiosperms. In this study we identify nine new isoprene synthases within the rosid angiosperms. We also document the capacity of a myrcene synthase in Humulus lupulus to produce isoprene. Isoprene synthases and (E)-β-ocimene synthases form a monophyletic group within the Tps-b clade of terpene synthases. No asterid genes fall within this clade. The chemistry of isoprene synthase and ocimene synthase is similar and likely affects the apparent relationships among Tps-b enzymes. The chronology of rosid evolution suggests a Cretaceous origin followed by many losses of isoprene synthase over the course of evolutionary history. The phylogenetic pattern of Tps-b genes indicates that isoprene emission from non-rosid angiosperms likely arose independently. PMID:23550753

  9. Towards a multi-node OpenACC Implementation of the ICON Model

    NASA Astrophysics Data System (ADS)

    Sawyer, Will; Zaengl, Guenther; Linardakis, Leonidas

    2014-05-01

    We have ported the Icosahedral Non-hydrostatic (ICON) model's dynamics solver to Graphical Processing Units (GPUs), which is a task within the Partnership for Advanced Computing in Europe (PRACE) Second Implementation Phase (2IP) Work Package 8 (WP8). Initial single-node OpenCL and CUDA-Fortran implementations of ICON's non-hydrostatic dynamical core (NHDC) resulted in a maximum factor of two speedup over the latest CPU nodes, e.g., a dual-socket Intel Sandybridge. While this performance was promising, ICON developers viewed neither OpenCL nor CUDA-Fortran as viable programming paradigms for the actual production code, and suggested instead the OpenACC standard as the proper paradigm for the multi-node GPU implementation, which was then undertaken in WP8. We will present the results of the multi-node OpenACC implementation of the ICON NHDC for hybrid multicore platforms. The code baseline is the ICON "DSL" (Domain Specific Language) testbed code, which is essentially a stripped-down version of the ICON model for dynamics simulations only. We will discuss on the OpenACC directives used for the port of the computational as well as the communication code to GPUs, and report the resulting GPU performance on NVIDIA K20x as compared to contemporary CPU architectures. In addition, the future roadmap for an accelerated ICON version will be presented. As a first step, we are now incorporating the OpenACC directives into the ICON development trunk, based on the feedback given to us from the ICON developers at the Max Planck Institute for Meteorology (MPI-M) and the German Weather Service (DWD). Moreover, we plan to port the ICON Climate physical parameterizations stemming from the ECHAM model to OpenACC. This step should enable the full ICON on many core platforms which support OpenACC. The resulting model should benefit climate researchers world-wide who plan to transition from ECHAM to ICON in the coming years.

  10. Classification of fungal chitin synthases.

    PubMed Central

    Bowen, A R; Chen-Wu, J L; Momany, M; Young, R; Szaniszlo, P J; Robbins, P W

    1992-01-01

    Comparison of the chitin synthase genes of Saccharomyces cerevisiae CHS1 and CHS2 with the Candida albicans CHS1 gene (UDP-N-acetyl-D-glucosamine:chitin 4-beta-N-acetylglucosaminyltransferase, EC 2.4.1.16) revealed two small regions of complete amino acid sequence conservation that were used to design PCR primers. Fragments homologous to chitin synthase (approximately 600 base pairs) were amplified from the genomic DNA of 14 fungal species. These fragments were sequenced, and their deduced amino acid sequences were aligned. With the exception of S. cerevisiae CHS1, the sequences fell into three distinct classes, which could represent separate functional groups. Within each class phylogenetic analysis was performed. Although not the major purpose of the investigation, this analysis tends to confirm some relationships consistent with current taxonomic groupings. Images PMID:1731323

  11. Analysis of gene expression profiles for cell wall modifying proteins and ACC synthases in soybean cyst nematode colonized roots, adventitious rooting hypocotyls, root tips, flooded roots, and IBA and ACC treatment roots

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We hypothesized that soybean cyst nematode (SCN) co-opts a part or all of one or more innate developmental process in soybean to establish its feeding structure, syncytium, in soybean roots. The syncytium in soybean roots is formed in a predominantly lateral direction within the vascular bundle by ...

  12. Regulation of the activities of African cassava mosaic virus promoters by the AC1, AC2, and AC3 gene products.

    PubMed

    Haley, A; Zhan, X; Richardson, K; Head, K; Morris, B

    1992-06-01

    DNA fragments comprising each of the promoter regions from the geminivirus African cassava mosaic virus (ACMV) were cloned into the pUC18-based vector, pG1, producing transcriptional fusions with the beta-glucuronidase gene (GUS) and nopaline synthase terminator sequence. The relative activity of each promoter construct was analyzed by a GUS expression assay of extracts from Nicotiana clevelandii protoplasts coelectroporated with the GUS reporter constructs and constructs in which individual ACMV open reading frames (ORFs) were placed under control of a cauliflower mosaic virus 35 S promoter. Results suggest repression of the AC1 gene by its gene product, which is required for ACMV DNA synthesis. The promoter activity observed for the single promoter for the DNA A genes encoding functions of spread and the regulation of replication (AC2 and AC3 ORFs) was unaffected by coelectroporation with any of the ACMV ORF constructs. Promoters for the AV1 (coat protein) gene and the two DNA B genes (BV1 and BC1) were activated by electroporation of the AC2 ORF construct. To a lesser extent promoters for the AV1 and BV1 genes were activated with the AC3 ORF construct. The same pattern of promoter repression and activation was observed when transgenic N. benthamiana plants expressing the GUS reporter constructions were inoculated with ACMV DNA A. PMID:1585657

  13. 5th International ACC Symposium: Future and Current Therapeutic Trials in Adrenocortical Carcinoma.

    PubMed

    Hoff, Ana O; Berruti, Alfredo

    2016-02-01

    Adrenocortical carcinoma (ACC) is a rare and complex disease associated with a high mortality rate. Despite intensive translational and clinical research, prognosis remains poor. Over the past decade, a significant effort has been made to develop multinational, collaborative studies to better understand the pathogenesis and clinical features of this rare disease in attempt to improve the therapeutic strategies and patient outcome. The results of both standard and newer treatments are discussed in this review as well as the recent discovery of pathways involved in ACC pathogenesis that provide the rationale to introduce new molecular target therapies. Finally, remaining issues regarding how to improve available therapies in adjuvant setting are raised and addressed. PMID:26728470

  14. Microfabricated AC impedance sensor

    DOEpatents

    Krulevitch, Peter; Ackler, Harold D.; Becker, Frederick; Boser, Bernhard E.; Eldredge, Adam B.; Fuller, Christopher K.; Gascoyne, Peter R. C.; Hamilton, Julie K.; Swierkowski, Stefan P.; Wang, Xiao-Bo

    2002-01-01

    A microfabricated instrument for detecting and identifying cells and other particles based on alternating current (AC) impedance measurements. The microfabricated AC impedance sensor includes two critical elements: 1) a microfluidic chip, preferably of glass substrates, having at least one microchannel therein and with electrodes patterned on both substrates, and 2) electrical circuits that connect to the electrodes on the microfluidic chip and detect signals associated with particles traveling down the microchannels. These circuits enable multiple AC impedance measurements of individual particles at high throughput rates with sufficient resolution to identify different particle and cell types as appropriate for environmental detection and clinical diagnostic applications.

  15. Biochemistry and genetics of ACC deaminase: a weapon to “stress ethylene” produced in plants

    PubMed Central

    Singh, Rajnish P.; Shelke, Ganesh M.; Kumar, Anil; Jha, Prabhat N.

    2015-01-01

    1-aminocyclopropane-1-carboxylate deaminase (ACCD), a pyridoxal phosphate-dependent enzyme, is widespread in diverse bacterial and fungal species. Owing to ACCD activity, certain plant associated bacteria help plant to grow under biotic and abiotic stresses by decreasing the level of “stress ethylene” which is inhibitory to plant growth. ACCD breaks down ACC, an immediate precursor of ethylene, to ammonia and α-ketobutyrate, which can be further metabolized by bacteria for their growth. ACC deaminase is an inducible enzyme whose synthesis is induced in the presence of its substrate ACC. This enzyme encoded by gene AcdS is under tight regulation and regulated differentially under different environmental conditions. Regulatory elements of gene AcdS are comprised of the regulatory gene encoding LRP protein and other regulatory elements which are activated differentially under aerobic and anaerobic conditions. The role of some additional regulatory genes such as AcdB or LysR may also be required for expression of AcdS. Phylogenetic analysis of AcdS has revealed that distribution of this gene among different bacteria might have resulted from vertical gene transfer with occasional horizontal gene transfer (HGT). Application of bacterial AcdS gene has been extended by developing transgenic plants with ACCD gene which showed increased tolerance to biotic and abiotic stresses in plants. Moreover, distribution of ACCD gene or its homolog's in a wide range of species belonging to all three domains indicate an alternative role of ACCD in the physiology of an organism. Therefore, this review is an attempt to explore current knowledge of bacterial ACC deaminase mediated physiological effects in plants, mode of enzyme action, genetics, distribution among different species, ecological role of ACCD and, future research avenues to develop transgenic plants expressing foreign AcdS gene to cope with biotic and abiotic stressors. Systemic identification of regulatory circuits

  16. Adolescent neighborhood quality predicts adult dACC response to social exclusion

    PubMed Central

    Beckes, Lane; Chango, Joanna; Allen, Joseph P.; Coan, James A.

    2015-01-01

    Neuroimaging studies using the social-exclusion paradigm Cyberball indicate increased dorsal anterior cingulate cortex (dACC) and right insula activity as a function of exclusion. However, comparatively less work has been done on how social status factors may moderate this finding. This study used the Cyberball paradigm with 85 (45 females) socio-economically diverse participants from a larger longitudinal sample. We tested whether neighborhood quality during adolescence would predict subsequent neural responding to social exclusion in young adulthood. Given previous behavioral studies indicating greater social vigilance and negative evaluation as a function of lower status, we expected that lower adolescent neighborhood quality would predict greater dACC activity during exclusion at young adulthood. Our findings indicate that young adults who lived in low-quality neighborhoods in adolescence showed greater dACC activity to social exclusion than those who lived in higher quality neighborhoods. Lower neighborhood quality also predicted greater prefrontal activation in the superior frontal gyrus, dorsal medial prefrontal cortex and the middle frontal gyrus, possibly indicating greater regulatory effort. Finally, this effect was not driven by subsequent ratings of distress during exclusion. In sum, adolescent neighborhood quality appears to potentiate neural responses to social exclusion in young adulthood, effects that are independent of felt distress. PMID:25349459

  17. Estrogen related receptor α (ERRα) a promising target for the therapy of adrenocortical carcinoma (ACC).

    PubMed

    Casaburi, Ivan; Avena, Paola; De Luca, Arianna; Chimento, Adele; Sirianni, Rosa; Malivindi, Rocco; Rago, Vittoria; Fiorillo, Marco; Domanico, Francesco; Campana, Carmela; Cappello, Anna Rita; Sotgia, Federica; Lisanti, Michael P; Pezzi, Vincenzo

    2015-09-22

    The pathogenesis of the adrenocortical cancer (ACC) involves integration of molecular signals and the interplay of different downstream pathways (i.e. IGFII/IGF1R, β-catenin, Wnt, ESR1). This tumor is characterized by limited therapeutic options and unsuccessful treatments. A useful strategy to develop an effective therapy for ACC is to identify a common downstream target of these multiple pathways. A good candidate could be the transcription factor estrogen-related receptor alpha (ERRα) because of its ability to regulate energy metabolism, mitochondrial biogenesis and signalings related to cancer progression. In this study we tested the effect of ERRα inverse agonist, XCT790, on the proliferation of H295R adrenocortical cancer cell line. Results from in vitro and in vivo experiments showed that XCT790 reduced H295R cell growth. The inhibitory effect was associated with impaired cell cycle progression which was not followed by any apoptotic event. Instead, incomplete autophagy and cell death by a necrotic processes, as a consequence of the cell energy failure, induced by pharmacological reduction of ERRα was evidenced. Our results indicate that therapeutic strategies targeting key factors such as ERRα that control the activity and signaling of bioenergetics processes in high-energy demanding tumors could represent an innovative/alternative therapy for the treatment of ACC. PMID:26312764

  18. Estrogen related receptor α (ERRα) a promising target for the therapy of adrenocortical carcinoma (ACC)

    PubMed Central

    Chimento, Adele; Sirianni, Rosa; Malivindi, Rocco; Rago, Vittoria; Fiorillo, Marco; Domanico, Francesco; Campana, Carmela; Cappello, Anna Rita; Sotgia, Federica; Lisanti, Michael P.; Pezzi, Vincenzo

    2015-01-01

    The pathogenesis of the adrenocortical cancer (ACC) involves integration of molecular signals and the interplay of different downstream pathways (i.e. IGFII/IGF1R, β-catenin, Wnt, ESR1). This tumor is characterized by limited therapeutic options and unsuccessful treatments. A useful strategy to develop an effective therapy for ACC is to identify a common downstream target of these multiple pathways. A good candidate could be the transcription factor estrogen-related receptor alpha (ERRα) because of its ability to regulate energy metabolism, mitochondrial biogenesis and signalings related to cancer progression. In this study we tested the effect of ERRα inverse agonist, XCT790, on the proliferation of H295R adrenocortical cancer cell line. Results from in vitro and in vivo experiments showed that XCT790 reduced H295R cell growth. The inhibitory effect was associated with impaired cell cycle progression which was not followed by any apoptotic event. Instead, incomplete autophagy and cell death by a necrotic processes, as a consequence of the cell energy failure, induced by pharmacological reduction of ERRα was evidenced. Our results indicate that therapeutic strategies targeting key factors such as ERRα that control the activity and signaling of bioenergetics processes in high-energy demanding tumors could represent an innovative/alternative therapy for the treatment of ACC. PMID:26312764

  19. WASTE-ACC: A computer model for analysis of waste management accidents

    SciTech Connect

    Nabelssi, B.K.; Folga, S.; Kohout, E.J.; Mueller, C.J.; Roglans-Ribas, J.

    1996-12-01

    In support of the U.S. Department of Energy`s (DOE`s) Waste Management Programmatic Environmental Impact Statement, Argonne National Laboratory has developed WASTE-ACC, a computational framework and integrated PC-based database system, to assess atmospheric releases from facility accidents. WASTE-ACC facilitates the many calculations for the accident analyses necessitated by the numerous combinations of waste types, waste management process technologies, facility locations, and site consolidation strategies in the waste management alternatives across the DOE complex. WASTE-ACC is a comprehensive tool that can effectively test future DOE waste management alternatives and assumptions. The computational framework can access several relational databases to calculate atmospheric releases. The databases contain throughput volumes, waste profiles, treatment process parameters, and accident data such as frequencies of initiators, conditional probabilities of subsequent events, and source term release parameters of the various waste forms under accident stresses. This report describes the computational framework and supporting databases used to conduct accident analyses and to develop source terms to assess potential health impacts that may affect on-site workers and off-site members of the public under various DOE waste management alternatives.

  20. The ACC strategy in biomineralization: the case of earthworm's amorphous spherulites

    NASA Astrophysics Data System (ADS)

    Briones, Maria J. I.; Alvarez-Otero, Rosa; Méndez, Jesús; Gago Duport, Luis

    2010-05-01

    The occurrence of amorphous calcium carbonate (ACC), an hydrated and highly soluble form of solid CaCO3, seems to be a common feature in all carbonate forming organisms such as mollusks, corals, echinoderms and crustaceans. The ubiquity of ACC in these Ca-carbonate biomineralizing systems, as a precursor of further crystalline phases, has recently open the interesting question about if the formation of an amorphous phase is a necessary step in the calcification process of all organisms and consequently, whether it would be possible to define the "amorphous precursor estategy" as a general mechanism in biomineralization. Neverthelees, although ACC appears to be widespread in these organisms very little is known about its particular role in the biomineralization scheme of the different phyla. The formation of CaCO3 spherulites in the calciferous glands of earthworms is a particular case of calcareous biomineralization involving the presence of ACC as a transient precursor phase [2]. Interestingly, the formation of crystalline carbonates via ACC in these organisms is not connected with skeleton building so it must play another functional role. In addition, the transient transformation stages can be followed by in situ spectrometric techniques and therefore, earthworms provide and adequate model to analyse the mutual interactions between ACC-solvent-and crystalline phases. In this study, we have analysed the morphological and structural transformations from the initial ACC spherulites until the formation of the crystalline phases: vaterite (and/or aragonite) and finally calcite, is accomplished. The characterization of ACC was done by performing in situ FT-IR, together with and HREM and Debye scherrer -XRD. The structural results were interpreted in the light of the histological study of the gland. The geometry of the secretory epithelium of the calciferous gland, as evidenced by TEM [2], shows the presence of irregulary shaped cells with their apical surface

  1. Trait impulsivity is related to ventral ACC and amygdala activity during primary reward anticipation

    PubMed Central

    Kerr, Kara L.; Avery, Jason A.; Barcalow, Joel C.; Moseman, Scott E.; Bodurka, Jerzy; Bellgowan, Patrick S. F.

    2015-01-01

    Trait impulsivity is characterized by behavioral disinhibition and rash decision-making that contribute to many maladaptive behaviors. Previous research demonstrates that trait impulsivity is related to the activity of brain regions underlying reward sensitivity and emotion regulation, but little is known about this relationship in the context of immediately available primary reward. This is unfortunate, as impulsivity in these contexts can lead to unhealthy behaviors, including poor food choices, dangerous drug use and risky sexual practices. In addition, little is known about the relationship between integration of reward and affective neurocircuitry, as measured by resting-state functional connectivity, and trait impulsivity in everyday life, as measured with a commonly used personality inventory. We therefore asked healthy adults to undergo a functional magnetic resonance imaging task in which they saw cues indicating the imminent oral administration of rewarding taste, as well as a resting-state scan. Trait impulsivity was associated with increased activation during anticipation of primary reward in the anterior cingulate cortex (ACC) and amygdala. Additionally, resting-state functional connectivity between the ACC and the right amygdala was negatively correlated with trait impulsivity. These findings demonstrate that trait impulsivity is related not only to ACC-amygdala activation but also to how tightly coupled these regions are to one another. PMID:24526181

  2. Trait impulsivity is related to ventral ACC and amygdala activity during primary reward anticipation.

    PubMed

    Kerr, Kara L; Avery, Jason A; Barcalow, Joel C; Moseman, Scott E; Bodurka, Jerzy; Bellgowan, Patrick S F; Simmons, W Kyle

    2015-01-01

    Trait impulsivity is characterized by behavioral disinhibition and rash decision-making that contribute to many maladaptive behaviors. Previous research demonstrates that trait impulsivity is related to the activity of brain regions underlying reward sensitivity and emotion regulation, but little is known about this relationship in the context of immediately available primary reward. This is unfortunate, as impulsivity in these contexts can lead to unhealthy behaviors, including poor food choices, dangerous drug use and risky sexual practices. In addition, little is known about the relationship between integration of reward and affective neurocircuitry, as measured by resting-state functional connectivity, and trait impulsivity in everyday life, as measured with a commonly used personality inventory. We therefore asked healthy adults to undergo a functional magnetic resonance imaging task in which they saw cues indicating the imminent oral administration of rewarding taste, as well as a resting-state scan. Trait impulsivity was associated with increased activation during anticipation of primary reward in the anterior cingulate cortex (ACC) and amygdala. Additionally, resting-state functional connectivity between the ACC and the right amygdala was negatively correlated with trait impulsivity. These findings demonstrate that trait impulsivity is related not only to ACC-amygdala activation but also to how tightly coupled these regions are to one another. PMID:24526181

  3. A functional cellulose synthase from ascidian epidermis

    PubMed Central

    Matthysse, Ann G.; Deschet, Karine; Williams, Melanie; Marry, Mazz; White, Alan R.; Smith, William C.

    2004-01-01

    Among animals, urochordates (e.g., ascidians) are unique in their ability to biosynthesize cellulose. In ascidians cellulose is synthesized in the epidermis and incorporated into a protective coat know as the tunic. A putative cellulose synthase-like gene was first identified in the genome sequences of the ascidian Ciona intestinalis. We describe here a cellulose synthase gene from the ascidian Ciona savignyi that is expressed in the epidermis. The predicted C. savignyi cellulose synthase amino acid sequence showed conserved features found in all cellulose synthases, including plants, but was most similar to cellulose synthases from bacteria, fungi, and Dictyostelium discoidium. However, unlike other known cellulose synthases, the predicted C. savignyi polypeptide has a degenerate cellulase-like region near the carboxyl-terminal end. An expression construct carrying the C. savignyi cDNA was found to restore cellulose biosynthesis to a cellulose synthase (CelA) minus mutant of Agrobacterium tumefaciens, showing that the predicted protein has cellulose synthase activity. The lack of cellulose biosynthesis in all other groups of metazoans and the similarity of the C. savignyi cellulose synthase to enzymes from cellulose-producing organisms support the hypothesis that the urochordates acquired the cellulose biosynthetic pathway by horizontal transfer. PMID:14722352

  4. Efficient heterocyclisation by (di)terpene synthases.

    PubMed

    Mafu, S; Potter, K C; Hillwig, M L; Schulte, S; Criswell, J; Peters, R J

    2015-09-11

    While cyclic ether forming terpene synthases are known, the basis for such heterocyclisation is unclear. Here it is reported that numerous (di)terpene synthases, particularly including the ancestral ent-kaurene synthase, efficiently produce isomers of manoyl oxide from the stereochemically appropriate substrate. Accordingly, such heterocyclisation is easily accomplished by terpene synthases. Indeed, the use of single residue changes to induce production of the appropriate substrate in the upstream active site leads to efficient bifunctional enzymes producing isomers of manoyl oxide, representing novel enzymatic activity. PMID:26214384

  5. AC magnetohydrodynamic microfluidic switch

    SciTech Connect

    Lemoff, A V; Lee, A P

    2000-03-02

    A microfluidic switch has been demonstrated using an AC Magnetohydrodynamic (MHD) pumping mechanism in which the Lorentz force is used to pump an electrolytic solution. By integrating two AC MHD pumps into different arms of a Y-shaped fluidic circuit, flow can be switched between the two arms. This type of switch can be used to produce complex fluidic routing, which may have multiple applications in {micro}TAS.

  6. ACS Symposium Support

    SciTech Connect

    Kenneth D. Jordan

    2010-02-20

    The funds from this DOE grant were used to help cover the travel costs of five students and postdoctoral fellows who attended a symposium on 'Hydration: From Clusters to Aqueous Solutions' held at the Fall 2007 American Chemical Society Meeting in Boston, MA, August 19-23. The Symposium was sponsored by the Physical Chemistry Division, ACS. The technical program for the meeting is available at http://phys-acs.org/fall2007.html.

  7. On the representation of the ACC circulation around the Kerguelen Plateau in an OGCM

    NASA Astrophysics Data System (ADS)

    Roquet, F.; Park, Y. H.; Madek, G.

    2009-04-01

    Due to its great meridional extent and relatively shallow depths, the Kerguelen Plateau constitutes a major barrier to the eastward flowing Antarctic Circumpolar Current (ACC) in the Indian sector of the Southern Ocean. While most of the ACC transport is deflected north of the Kerguelen Islands, the remainder (~50 x 106 m3 s-1) must pass south of the islands, most probably through the Fawn Trough (56°S, 77°E, 2650m) and Princess Elizabeth Trough (64°S, 82°E, 3650 m). Yet, lack of observations in this area still hampers our knowledge on the exact partitioning and its temporal variability of the circumpolar flow through the abovementioned three passages. We have developed a regional configuration of the Southern Indian Ocean using the eddy-permitting (1/4°) global ocean/sea-ice model NEMO. A 20-year long simulation has been performed, using the open boundary conditions derived from the KAB001 interannual experiment. The KAB001 experiment is characterized by a slight 3D TS restoring in polar areas, which allows the continuous maintaining of adequate bottom properties around Antarctica, and thus yielding a realistic and stable ACC transport (~150 x 106 m3 s-1 at Drake Passage). The main ACC veins detected from satellite and in situ observations are consistently well represented in our regional model. In particular, the presence of a strong topographically controlled northeastward current through the Fawn Trough channelling most of the Enderby Basin water has been confirmed. The lagrangian diagnostic tool ARIANE has been used on the model velocity field to show the ACC circulation splitting into several branches. It also allows a precise diagnostic of the temporal variability of these branches as well as the transformation of water masses along their trajectories. We verified that the area just downstream of the Fawn Trough in the Australian-Antarctic Basin is an outstanding region of enhanced water mass transformation where waters of different origins collide and

  8. Producing biofuels using polyketide synthases

    DOEpatents

    Katz, Leonard; Fortman, Jeffrey L; Keasling, Jay D

    2013-04-16

    The present invention provides for a non-naturally occurring polyketide synthase (PKS) capable of synthesizing a carboxylic acid or a lactone, and a composition such that a carboxylic acid or lactone is included. The carboxylic acid or lactone, or derivative thereof, is useful as a biofuel. The present invention also provides for a recombinant nucleic acid or vector that encodes such a PKS, and host cells which also have such a recombinant nucleic acid or vector. The present invention also provides for a method of producing such carboxylic acids or lactones using such a PKS.

  9. Assessing the effects of heavy metals in ACC deaminase and IAA production on plant growth-promoting bacteria.

    PubMed

    Carlos, Mendoza-Hernández José; Stefani, Perea-Vélez Yazmin; Janette, Arriola-Morales; Melani, Martínez-Simón Sara; Gabriela, Pérez-Osorio

    2016-01-01

    This study poses a methodology in order to simultaneously quantify ACC deaminase and IAA levels in the same culture medium. Ten bacterial strains isolated from plant rhizosphere naturally settled in mining residues were chosen. These bacterial strains were characterized as PGPB, and all of them showed at least three characteristics (indole-3 acetic acid and siderophore production, ACC deaminase enzyme activity, and inorganic phosphate solubilization). Taxonomic identification showed that the strains belong to Enterobacter, Serratia, Klebsiella, and Escherichia genera. Similarly, both the ACC deaminase enzyme activity and the IAA synthesis in the presence of Cu, As, Pb, Ni, Cd, and Mn were measured. The results showed that both the ACC deaminase enzyme activity and the IAA synthesis were higher with the Pb, As, and Cu treatments than with the Escherichia N16, Enterobacter K131, Enterobacter N9, and Serratia K120 control treatments. On the other hand, Ni, Cd, and Mn negatively affected both the ACC deaminase enzyme activity and the IAA production on every bacterium except on the Klebsiella Mc173 strain. Serratia K120 bacterium got a positive correlation between ACC deaminase and IAA in the presence of every heavy metal, and it also promoted Helianthus annuus plant growth, showing a potential use in phytoremediation systems. PMID:27296962

  10. Molecular cloning, expression, and stress response of the estrogen-related receptor gene (AccERR) from Apis cerana cerana

    NASA Astrophysics Data System (ADS)

    Zhang, Weixing; Zhu, Ming; Zhang, Ge; Liu, Feng; Wang, Hongfang; Guo, Xingqi; Xu, Baohua

    2016-04-01

    Estrogen-related receptor (ERR), which belongs to the nuclear receptor superfamily, has been implicated in diverse physiological processes involving the estrogen signaling pathway. However, little information is available on ERR in Apis cerana cerana. In this report, we isolated the ERR gene and investigated its involvement in antioxidant defense. Quantitative real-time polymerase chain reaction (qPCR) revealed that the highest mRNA expression occurred in eggs during different developmental stages. The expression levels of AccERR were highest in the muscle, followed by the rectum. The predicted transcription factor binding sites in the promoter of AccERR suggested that AccERR potentially functions in early development and in environmental stress responses. The expression of AccERR was induced by cold (4 °C), heat (42 °C), ultraviolet light (UV), HgCl2, and various types of pesticides (phoxim, deltamethrin, triadimefon, and cyhalothrin). Western blot was used to measure the expression levels of AccERR protein. These data suggested that AccERR might play a vital role in abiotic stress responses.

  11. The human ACC2 CT-domain C-terminus is required for full functionality and has a novel twist

    SciTech Connect

    Madauss, Kevin P.; Burkhart, William A.; Consler, Thomas G.; Cowan, David J.; Gottschalk, William K.; Miller, Aaron B.; Short, Steven A.; Tran, Thuy B.; Williams, Shawn P.

    2009-05-01

    The use of biophysical assays permitted the identification of a specific human ACC2 carboxyl transferase (CT) domain mutant that binds inhibitors and crystallizes in their presence. This mutant led to determination of the human ACC2 CT domain–CP-640186 complex crystal structure, which revealed differences in the inhibitor conformation from the yeast protein complex that are caused by differing residues in the binding pocket. Inhibition of acetyl-CoA carboxylase (ACC) may prevent lipid-induced insulin resistance and type 2 diabetes, making the enzyme an attractive pharmaceutical target. Although the enzyme is highly conserved amongst animals, only the yeast enzyme structure is available for rational drug design. The use of biophysical assays has permitted the identification of a specific C-terminal truncation of the 826-residue human ACC2 carboxyl transferase (CT) domain that is both functionally competent to bind inhibitors and crystallizes in their presence. This C-terminal truncation led to the determination of the human ACC2 CT domain–CP-640186 complex crystal structure, which revealed distinctions from the yeast-enzyme complex. The human ACC2 CT-domain C-terminus is comprised of three intertwined α-helices that extend outwards from the enzyme on the opposite side to the ligand-binding site. Differences in the observed inhibitor conformation between the yeast and human structures are caused by differing residues in the binding pocket.

  12. Molecular cloning, expression and antioxidant characterisation of a typical thioredoxin gene (AccTrx2) in Apis cerana cerana.

    PubMed

    Yao, Pengbo; Hao, Lili; Wang, Fang; Chen, Xiaobo; Yan, Yan; Guo, Xingqi; Xu, Baohua

    2013-09-15

    Thioredoxins (Trxs) are a family of small, highly conserved and ubiquitous proteins that are involved in protecting organisms against toxic reactive oxygen species (ROS). In this study, a typical thioredoxin 2 gene was isolated from Apis cerana cerana, AccTrx2. The full-length cDNA sequence of AccTrx2 was composed of 407 bp containing a 318 bp open reading frame (ORF) that encodes a predicted protein of 105 amino acids, 11.974 kDa and an isoelectric point of 4.45. Expression profile of AccTrx2 as determined by a quantitative real-time PCR (qRT-PCR) analysis was higher in brain than in other tissues, with its highest transcript occurring on the 15day post-emergence adult and upregulated by such abiotic stresses as 4 °C, 16 °C, 25 °C, H2O2, cyhalothrin, acaricide, paraquat, phoxime and mercury (HgCl2) treatments. However, AccTrx2 was slightly repressed when exposed to 42 °C treatment. Characterisation of the recombinant protein showed that the purified AccTrx2 had insulin disulfide reductase activity and could protect DNA from ROS damage. These results indicate that AccTrx2 functions as an antioxidant that plays an important role in response to oxidative stress. PMID:23747404

  13. Molecular cloning, expression, and stress response of the estrogen-related receptor gene (AccERR) from Apis cerana cerana.

    PubMed

    Zhang, Weixing; Zhu, Ming; Zhang, Ge; Liu, Feng; Wang, Hongfang; Guo, Xingqi; Xu, Baohua

    2016-04-01

    Estrogen-related receptor (ERR), which belongs to the nuclear receptor superfamily, has been implicated in diverse physiological processes involving the estrogen signaling pathway. However, little information is available on ERR in Apis cerana cerana. In this report, we isolated the ERR gene and investigated its involvement in antioxidant defense. Quantitative real-time polymerase chain reaction (qPCR) revealed that the highest mRNA expression occurred in eggs during different developmental stages. The expression levels of AccERR were highest in the muscle, followed by the rectum. The predicted transcription factor binding sites in the promoter of AccERR suggested that AccERR potentially functions in early development and in environmental stress responses. The expression of AccERR was induced by cold (4 °C), heat (42 °C), ultraviolet light (UV), HgCl2, and various types of pesticides (phoxim, deltamethrin, triadimefon, and cyhalothrin). Western blot was used to measure the expression levels of AccERR protein. These data suggested that AccERR might play a vital role in abiotic stress responses. PMID:26922780

  14. Polyester synthases: natural catalysts for plastics.

    PubMed Central

    Rehm, Bernd H A

    2003-01-01

    Polyhydroxyalkanoates (PHAs) are biopolyesters composed of hydroxy fatty acids, which represent a complex class of storage polyesters. They are synthesized by a wide range of different Gram-positive and Gram-negative bacteria, as well as by some Archaea, and are deposited as insoluble cytoplasmic inclusions. Polyester synthases are the key enzymes of polyester biosynthesis and catalyse the conversion of (R)-hydroxyacyl-CoA thioesters to polyesters with the concomitant release of CoA. These soluble enzymes turn into amphipathic enzymes upon covalent catalysis of polyester-chain formation. A self-assembly process is initiated resulting in the formation of insoluble cytoplasmic inclusions with a phospholipid monolayer and covalently attached polyester synthases at the surface. Surface-attached polyester synthases show a marked increase in enzyme activity. These polyester synthases have only recently been biochemically characterized. An overview of these recent findings is provided. At present, 59 polyester synthase structural genes from 45 different bacteria have been cloned and the nucleotide sequences have been obtained. The multiple alignment of the primary structures of these polyester synthases show an overall identity of 8-96% with only eight strictly conserved amino acid residues. Polyester synthases can been assigned to four classes based on their substrate specificity and subunit composition. The current knowledge on the organization of the polyester synthase genes, and other genes encoding proteins related to PHA metabolism, is compiled. In addition, the primary structures of the 59 PHA synthases are aligned and analysed with respect to highly conserved amino acids, and biochemical features of polyester synthases are described. The proposed catalytic mechanism based on similarities to alpha/beta-hydrolases and mutational analysis is discussed. Different threading algorithms suggest that polyester synthases belong to the alpha/beta-hydrolase superfamily, with

  15. ACC2 gene polymorphisms, metabolic syndrome, and gene-nutrient interactions with dietary fat

    PubMed Central

    Phillips, Catherine M.; Goumidi, Louisa; Bertrais, Sandrine; Field, Martyn R.; Cupples, L. Adrienne; Ordovas, Jose M.; McMonagle, Jolene; Defoort, Catherine; Lovegrove, Julie A.; Drevon, Christian A.; Blaak, Ellen E.; Kiec-Wilk, Beata; Riserus, Ulf; Lopez-Miranda, Jose; McManus, Ross; Hercberg, Serge; Lairon, Denis; Planells, Richard; Roche, Helen M.

    2010-01-01

    Acetyl-CoA carboxylase β (ACC2) plays a key role in fatty acid synthesis and oxidation pathways. Disturbance of these pathways is associated with impaired insulin responsiveness and metabolic syndrome (MetS). Gene-nutrient interactions may affect MetS risk. This study determined the relationship between ACC2 polymorphisms (rs2075263, rs2268387, rs2284685, rs2284689, rs2300453, rs3742023, rs3742026, rs4766587, and rs6606697) and MetS risk, and whether dietary fatty acids modulate this in the LIPGENE-SU.VI.MAX study of MetS cases and matched controls (n = 1754). Minor A allele carriers of rs4766587 had increased MetS risk (OR 1.29 [CI 1.08, 1.58], P = 0.0064) compared with the GG homozygotes, which may in part be explained by their increased body mass index (BMI), abdominal obesity, and impaired insulin sensitivity (P < 0.05). MetS risk was modulated by dietary fat intake (P = 0.04 for gene-nutrient interaction), where risk conferred by the A allele was exacerbated among individuals with a high-fat intake (>35% energy) (OR 1.62 [CI 1.05, 2.50], P = 0.027), particularly a high intake (>5.5% energy) of n-6 polyunsaturated fat (PUFA) (OR 1.82 [CI 1.14, 2.94], P = 0.01; P = 0.05 for gene-nutrient interaction). Saturated and monounsaturated fat intake did not modulate MetS risk. Importantly, we replicated some of these findings in an independent cohort. In conclusion, the ACC2 rs4766587 polymorphism influences MetS risk, which was modulated by dietary fat, suggesting novel gene-nutrient interactions. PMID:20855566

  16. Capteurs monopodes pour mesures accélérométriques

    NASA Astrophysics Data System (ADS)

    Delaite, R.; Valentin, J.-P.

    1993-08-01

    A new design for accelerometric measurements sensors is described. It uses a plate vibrating in thickness shear mode, maintained by the means of a single holder located at the crystal edge. This mounting does cancel the mechanical and thermal stresses which generally modify the sensor output signal. So the ratio signal/noise of a thickness shear accelerometer is improved and the intrinsic sensitivity is multiplied by a factor 40, by comparison with the sensitivity of a thickness shear plate bonded by the means of two opposite holders. Un nouveau dispositif destiné aux mesures d'accélération est présenté. Il met en œuvre une lame vibrant en cisaillement d'épaisseur, fixée à sa structure de maintien par l'intermédiaire d'une unique liaison. Ce montage permet d'éliminer les contraintes mécaniques et thermiques qui perturbent habituellement le signal de mesure, et qui sont liées soit au montage des éléments du capteur, soit aux variations rapides de température qui interviennent lors de la mise en fonctionnement du capteur. Le rapport signal/bruit d'un accéléromètre à lame vibrant en cisaillement d'épaisseur s'en trouve amélioré et la sensibilité à l'accélération est multipliée par un facteur 40, comparée à celle d'un capteur qui serait constitué d'une lame vibrant en cisaillement d'épaisseur, fixée par deux liaisons diamétralement opposées.

  17. Tevatron AC dipole system

    SciTech Connect

    Miyamoto, R.; Kopp, S.E.; Jansson, A.; Syphers, M.J.; /Fermilab

    2007-06-01

    The AC dipole is an oscillating dipole magnet which can induce large amplitude oscillations without the emittance growth and decoherence. These properties make it a good tool to measure optics of a hadron synchrotron. The vertical AC dipole for the Tevatron is powered by an inexpensive high power audio amplifier since its operating frequency is approximately 20 kHz. The magnet is incorporated into a parallel resonant system to maximize the current. The use of a vertical pinger magnet which has been installed in the Tevatron made the cost relatively inexpensive. Recently, the initial system was upgraded with a more powerful amplifier and oscillation amplitudes up to 2-3{sigma} were achieved with the 980 GeV proton beam. This paper discusses details of the Tevatron AC dipole system and also shows its test results.

  18. Higher Order Modes HOM___s in Coupled Cavities of the Flash Module ACC39

    SciTech Connect

    Shinton, I.R.R.; Jones, R.M.; Li, Z.; Zhang, P.; /Manchester U. /Cockcroft Inst. Accel. Sci. Tech. /DESY

    2012-09-14

    We analyse the higher order modes (HOM's) in the 3.9GHz bunch shaping cavities installed in the FLASH facility at DESY. A suite of finite element computer codes (including HFSS and ACE3P) and globalised scattering matrix calculations (GSM) are used to investigate the modes in these cavities. This study is primarily focused on the dipole component of the multiband expansion of the wakefield, with the emphasis being on the development of a HOM-based BPM system for ACC39. Coupled inter-cavity modes are simulated together with a limited band of trapped modes.

  19. BACCHUS: Brussels Automatic Code for Characterizing High accUracy Spectra

    NASA Astrophysics Data System (ADS)

    Masseron, Thomas; Merle, Thibault; Hawkins, Keith

    2016-05-01

    BACCHUS (Brussels Automatic Code for Characterizing High accUracy Spectra) derives stellar parameters (Teff, log g, metallicity, microturbulence velocity and rotational velocity), equivalent widths, and abundances. The code includes on the fly spectrum synthesis, local continuum normalization, estimation of local S/N, automatic line masking, four methods for abundance determinations, and a flagging system aiding line selection. BACCHUS relies on the grid of MARCS model atmospheres, Masseron's model atmosphere thermodynamic structure interpolator, and the radiative transfer code Turbospectrum (ascl:1205.004).

  20. ac bidirectional motor controller

    NASA Technical Reports Server (NTRS)

    Schreiner, K.

    1988-01-01

    Test data are presented and the design of a high-efficiency motor/generator controller at NASA-Lewis for use with the Space Station power system testbed is described. The bidirectional motor driver is a 20 kHz to variable frequency three-phase ac converter that operates from the high-frequency ac bus being designed for the Space Station. A zero-voltage-switching pulse-density-modulation technique is used in the converter to shape the low-frequency output waveform.

  1. Crystal structure of riboflavin synthase

    SciTech Connect

    Liao, D.-I.; Wawrzak, Z.; Calabrese, J.C.; Viitanen, P.V.; Jordan, D.B.

    2010-03-05

    Riboflavin synthase catalyzes the dismutation of two molecules of 6,7-dimethyl-8-(1'-D-ribityl)-lumazine to yield riboflavin and 4-ribitylamino-5-amino-2,6-dihydroxypyrimidine. The homotrimer of 23 kDa subunits has no cofactor requirements for catalysis. The enzyme is nonexistent in humans and is an attractive target for antimicrobial agents of organisms whose pathogenicity depends on their ability to biosynthesize riboflavin. The first three-dimensional structure of the enzyme was determined at 2.0 {angstrom} resolution using the multiwavelength anomalous diffraction (MAD) method on the Escherichia coli protein containing selenomethionine residues. The homotrimer consists of an asymmetric assembly of monomers, each of which comprises two similar {beta} barrels and a C-terminal {alpha} helix. The similar {beta} barrels within the monomer confirm a prediction of pseudo two-fold symmetry that is inferred from the sequence similarity between the two halves of the protein. The {beta} barrels closely resemble folds found in phthalate dioxygenase reductase and other flavoproteins. The three active sites of the trimer are proposed to lie between pairs of monomers in which residues conserved among species reside, including two Asp-His-Ser triads and dyads of Cys-Ser and His-Thr. The proposed active sites are located where FMN (an analog of riboflavin) is modeled from an overlay of the {beta} barrels of phthalate dioxygenase reductase and riboflavin synthase. In the trimer, one active site is formed, and the other two active sites are wide open and exposed to solvent. The nature of the trimer configuration suggests that only one active site can be formed and be catalytically competent at a time.

  2. AC/RF Superconductivity

    SciTech Connect

    Ciovati, Gianluigi

    2015-02-01

    This contribution provides a brief introduction to AC/RF superconductivity, with an emphasis on application to accelerators. The topics covered include the surface impedance of normal conductors and superconductors, the residual resistance, the field dependence of the surface resistance, and the superheating field.

  3. AC solar cell

    SciTech Connect

    Schutten, H.P.; Benjamin, J.A.; Lade, R.W.

    1986-03-18

    An AC solar cell is described comprising: a pair of PN junction type solar cells connected in antiparallel between a pair of main terminals; and means for electrically directing light alternatingly without mechanical movement on the PN junctions to generate an alternating potential across the main terminals.

  4. AC 67 Launch Video

    NASA Technical Reports Server (NTRS)

    1987-01-01

    Live footage of the Unmanned Atlas Centaur (AC) 67 launch is presented on March 26, 1987 at the WESH television station in Florida. Lightning is shown after 49 seconds into the flight. The vehicle is totally destroyed due to a cloud-to-ground lightning flash.

  5. ACC Synthase Genes are Polymorphic in Watermelon (Citrullus spp.) and Differentially Expressed in Flowers and in Response to Auxin and Gibberellin

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The flowering pattern of watermelon species (Citrullus) is either monoecious or andromonoecious. In watermelon (Citrullus lanatus L.), ethylene promotes male flower development while inhibitors of ethylene promote pistillate (pistil-bearing) flower formation. This is opposite to the feminizing effec...

  6. ACC deaminase and IAA producing growth promoting bacteria from the rhizosphere soil of tropical rice plants.

    PubMed

    Bal, Himadri Bhusan; Das, Subhasis; Dangar, Tushar K; Adhya, Tapan K

    2013-12-01

    Beneficial plant-associated bacteria play a key role in supporting and/or promoting plant growth and health. Plant growth promoting bacteria present in the rhizosphere of crop plants can directly affect plant metabolism or modulate phytohormone production or degradation. We isolated 355 bacteria from the rhizosphere of rice plants grown in the farmers' fields in the coastal rice field soil from five different locations of the Ganjam district of Odisha, India. Six bacteria producing both ACC deaminase (ranging from 603.94 to 1350.02 nmol α-ketobutyrate mg(-1)  h(-1) ) and indole acetic acid (IAA; ranging from 10.54 to 37.65 μM ml(-1) ) in pure cultures were further identified using polyphasic taxonomy including BIOLOG((R)) , FAME analysis and the 16S rRNA gene sequencing. Phylogenetic analyses of the isolates resulted into five major clusters to include members of the genera Bacillus, Microbacterium, Methylophaga, Agromyces, and Paenibacillus. Seed inoculation of rice (cv. Naveen) by the six individual PGPR isolates had a considerable impact on different growth parameters including root elongation that was positively correlated with ACC deaminase activity and IAA production. The cultures also had other plant growth attributes including ammonia production and at least two isolates produced siderophores. Study indicates that presence of diverse rhizobacteria with effective growth-promoting traits, in the rice rhizosphere, may be exploited for a sustainable crop management under field conditions. PMID:23681643

  7. The 2013 ACC/AHA Cholesterol Treatment Guidelines: Applicability to Patients with Diabetes.

    PubMed

    Ziaeian, Boback; Dinkler, John; Guo, Yuanlin; Watson, Karol

    2016-02-01

    Atherosclerotic cardiovascular disease (ASCVD) is the leading cause of death worldwide and the management of blood cholesterol is a cornerstone of medical therapy for the primary and secondary prevention of cardiovascular disease. Patients with diabetes represent an important high-risk group in whom clinicians should advocate the use of statins and lifestyle modification for the reduction of ASCVD. The recent 2013 ACC/AHA guidelines on managing blood cholesterol provide an important framework for the effective implementation of this important risk reduction strategy. The guidelines identify four groups of individuals who have been shown to benefit from statin therapy and update the dosing and monitoring recommendations based on evidence from published, large-scale randomized controlled trials (RCTs) with clinical hard endpoints. Primary care physicians and specialists play key roles in identifying populations at elevated ASCVD risk and providing effective care for patients, especially those with diabetes. This article will summarize the 2013 ACC/AHA guidelines on managing blood cholesterol and provide a practical management overview in order to facilitate implementation of these guidelines for patients with diabetes. PMID:26803649

  8. Various effects of fluorescent bacteria of the genus Pseudomonas containing ACC deaminase on wheat seedling growth.

    PubMed

    Magnucka, Elżbieta G; Pietr, Stanisław J

    2015-12-01

    The study evaluates the effect of rhizobacteria having 1-aminocyclopropane-1-carboxylate deaminase (ACCd) on the development of wheat seedlings. This enzyme has been proposed to play a key role in microbe-plant association. Three fluorescent pseudomonads containing this deaminase were selected from 70 strains of pseudomonads isolated from rhizosphere of wheat (Triticum aestivum L.) and rape (Brassica napus L.). These bacteria, varied significantly in the ability to both biosynthesize auxins and hydrolyze ACC. Among them, Pseudomonas brassicacearum subsp. brassicacearum strain RZ310 presented the highest activities of ACC deaminase during 96h of growth in liquid Dworkin and Foster (DF) salt medium. Additionally, this rape rhizosphere strain did not produce indoles. Two other isolates, Pseudomonas sp. PO283 and Pseudomonas sp. PO366, secreted auxins only in the presence of their precursor. Phylogenetic analysis of the 16S rRNA gene and four other protein-encoding genes indicated that these wheat rhizosphere isolates belonged to the fluorescent Pseudomonas group. Moreover, the effects of these strains on wheat seedling growth under in vitro conditions were markedly dependent on both their cell suspensions used to grain inoculation and nutrient conditions. Strains tested had beneficial influence on wheat seedlings mainly at low cell densities. In addition, access to nutrients markedly changed bacteria action on cereal growth. Their presence generally favored the positive effects of pseudomonads on length and the estimated biomasses of wheat coleoptiles. Despite these general rules, impacts of each isolate on the growth parameters of cereal seedlings were unique. PMID:25983132

  9. 5th International ACC Symposium: Classification of Adrenocortical Cancers from Pathology to Integrated Genomics: Real Advances or Lost in Translation?

    PubMed

    de Krijger, Ronald E; Bertherat, Jérôme

    2016-02-01

    For the clinician, despite its rarity, adrenocortical cancer is a heterogeneous tumor both in term of steroid excess and tumor evolution. For patient management, it is crucial to have an accurate vision of this heterogeneity, in order to use a correct tumor classification. Pathology is the best way to classify operated adrenocortical tumors: to recognize their adrenocortical nature and to differentiate benign from malignant tumors. Among malignant tumors pathology also aims at prognosis assessment. Although progress has being made for prognosis assessment, there is still a need for improvement. Recent studies have established the value of Ki67 for adrenocortical cancer (ACC) prognostication, aiming also at standardization to reduce variability. The use of genomics to study adrenocortical tumors gives a very new insight in their pathogenesis and molecular classification. Genomics studies of ACC give now a clear description of the mRNA (transcriptome) and miRNA expression profile, as well as chromosomal and methylation alterations. Exome sequencing also established firmly the list of the main ACC driver genes. Interestingly, genomics study of ACC also revealed subtypes of malignant tumors with different pattern of molecular alterations, associated with different outcome. This leads to a new vision of adrenocortical tumors classification based on molecular analysis. Interestingly, these molecular classifications meet also the results of pathological analysis. This opens new perspectives on the development and use of various molecular tools to classify, along with pathological analysis, ACC, and guides patient management at the area of precision medicine. PMID:26676358

  10. Monitoring apoptosis of TK-GFP-expressing ACC-M cells induced by ACV using FRET technique

    NASA Astrophysics Data System (ADS)

    Xiong, Tao; Zhang, Zhihong; Lin, Juqiang; Yang, Jie; Zeng, Shaoqun; Luo, Qingming

    2006-05-01

    Apoptosis is an evolutionary conserved cellular process that plays an important role during development, but it is also involved in tissue homeostasis and in many diseases. To study the characteristics of suicide gene system of the herpes simplex virus thymidine kinase (HSV-tk) gene in tumor cells and explore the apoptosis phenomena in this system and its effect on the human adenoid cystic carcinoma line ACC-M cell, we detected apoptosis of CD3- (ECFP-CRS-DsRed) and TK-GFP-expressing ACC-M (ACC-M-TK-GFP-CD3) cells induced by acyclovir (ACV) using fluorescence resonance energy transfer (FRET) technique. CD3 is a FRET-based indicator for activity of caspase-3, which is composed of an enhanced cyan fluorescent protein, a caspase-3 sensitive linker, and a red fluorescent protein from Discosoma with efficient maturation property. FRET from ECFP to DsRed could be detected in normal ACC-M-TK-GFP-CD3 cells, and the FRET efficient was remarkably decreased and then disappeared during the cells apoptosis induced by ACV. It was due to the activated caspase-3 cleaved the CD3 fusion protein. In this study, the results suggested that the ACV-induced apoptosis of ACC-M-TK-GFP-CD3 cells was through caspase-3 pathway.

  11. Monitoring apoptosis of TK-GFP-expressing ACC-M cells induced by ACV using FRET technique

    NASA Astrophysics Data System (ADS)

    Xiong, Tao; Zhang, Zhihong; Lin, Juqiang; Yang, Jie; Zeng, Shaoqun; Luo, Qingming

    2006-09-01

    Apoptosis is an evolutionary conserved cellular process that plays an important role during development, but it is also involved in tissue homeostasis and in many diseases. To study the characteristics of suicide gene system of the herpes simplex virus thymidine kinase (HSV-tk) gene in tumor cells and explore the apoptosis phenomena in this system and its effect on the human adenoid cystic carcinoma line ACC-M cell, we detected apoptosis of CD3- (ECFP-CRS-DsRed) and TK-GFP-expressing ACC-M (ACC-M-TK-GFP-CD3) cells induced by acyclovir (ACV) using fluorescence resonance energy transfer (FRET) technique. CD3 is a FRET-based indicator for activity of caspase-3, which is composed of an enhanced cyan fluorescent protein, a caspase-3 sensitive linker, and a red fluorescent protein from Discosoma with efficient maturation property. FRET from ECFP to DsRed could be detected in normal ACC-M-TK-GFP-CD3 cells, and the FRET efficient was remarkably decreased and then disappeared during the cells apoptosis induced by ACV. It was due to the activated caspase-3 cleaved the CD3 fusion protein. In this study, the results suggested that the AVC-induced apoptosis of ACC-M-TK-GFP-CD3 cells was through caspase-3 pathway.

  12. Identification and characterization of an Apis cerana cerana Delta class glutathione S-transferase gene (AccGSTD) in response to thermal stress.

    PubMed

    Yan, Huiru; Jia, Haihong; Wang, Xiuling; Gao, Hongru; Guo, Xingqi; Xu, Baohua

    2013-02-01

    Glutathione S-transferases (GSTs) are members of a multifunctional enzyme super family that plays a pivotal role in both insecticide resistance and protection against oxidative stress. In this study, we identified a single-copy gene, AccGSTD, as being a Delta class GST in the Chinese honey bee (Apis cerana cerana). A predicted antioxidant response element, CREB, was found in the 1,492-bp 5'-flanking region, suggesting that AccGSTD may be involved in oxidative stress response pathways. Real-time PCR and immunolocalization studies demonstrated that AccGSTD exhibited both developmental- and tissue-specific expression patterns. During development, AccGSTD transcript was increased in adults. The AccGSTD expression level was the highest in the honey bee brain. Thermal stress experiments demonstrated that AccGSTD could be significantly upregulated by temperature changes in a time-dependent manner. It is hypothesized that high expression levels might be due to the increased levels of oxidative stress caused by the temperature challenges. Additionally, functional assays of the recombinant AccGSTD protein revealed that AccGSTD has the capability to protect DNA from oxidative damage. Taken together, these data suggest that AccGSTD may be responsible for antioxidant defense in adult honey bees. PMID:23275971

  13. Identification and characterization of an Apis cerana cerana Delta class glutathione S-transferase gene ( AccGSTD) in response to thermal stress

    NASA Astrophysics Data System (ADS)

    Yan, Huiru; Jia, Haihong; Wang, Xiuling; Gao, Hongru; Guo, Xingqi; Xu, Baohua

    2013-02-01

    Glutathione S-transferases (GSTs) are members of a multifunctional enzyme super family that plays a pivotal role in both insecticide resistance and protection against oxidative stress. In this study, we identified a single-copy gene, AccGSTD, as being a Delta class GST in the Chinese honey bee ( Apis cerana cerana). A predicted antioxidant response element, CREB, was found in the 1,492-bp 5'-flanking region, suggesting that AccGSTD may be involved in oxidative stress response pathways. Real-time PCR and immunolocalization studies demonstrated that AccGSTD exhibited both developmental- and tissue-specific expression patterns. During development, AccGSTD transcript was increased in adults. The AccGSTD expression level was the highest in the honey bee brain. Thermal stress experiments demonstrated that AccGSTD could be significantly upregulated by temperature changes in a time-dependent manner. It is hypothesized that high expression levels might be due to the increased levels of oxidative stress caused by the temperature challenges. Additionally, functional assays of the recombinant AccGSTD protein revealed that AccGSTD has the capability to protect DNA from oxidative damage. Taken together, these data suggest that AccGSTD may be responsible for antioxidant defense in adult honey bees.

  14. Coexistence of Two Forms of LTP in ACC Provides a Synaptic Mechanism for the Interactions between Anxiety and Chronic Pain

    PubMed Central

    Koga, Kohei; Descalzi, Giannina; Chen, Tao; Ko, Hyoung-Gon; Lu, Jinshan; Li, Shermaine; Son, Junehee; Kim, TaeHyun; Kwak, Chuljung; Huganir, Richard L.; Zhao, Ming-gao; Kaang, Bong-Kiun; Collingridge, Graham L.; Zhuo, Min

    2015-01-01

    SUMMARY Chronic pain can lead to anxiety and anxiety can enhance the sensation of pain. Unfortunately, little is known about the synaptic mechanisms that mediate these re-enforcing interactions. Here we characterized two forms of long-term potentiation (LTP) in the anterior cingulate cortex (ACC); a presynaptic form (pre-LTP) that requires kainate receptors and a postsynaptic form (post-LTP) that requires N-methyl-D-aspartate receptors. Pre-LTP also involves adenylyl cyclase and protein kinase A and is expressed via a mechanism involving hyperpolarization-activated cyclic nucleotide-gated (HCN) channels. Interestingly, chronic pain and anxiety both result in selective occlusion of pre-LTP. Significantly, microinjection of the HCN blocker ZD7288 into the ACC in vivo produces both anxiolytic and analgesic effects. Our results provide a mechanism by which two forms of LTP in the ACC may converge to mediate the interaction between anxiety and chronic pain. PMID:25556835

  15. Increased ability of transgenic plants expressing the bacterial enzyme ACC deaminase to accumulate Cd, Co, Cu, Ni, Pb, and Zn.

    PubMed

    Grichko, V P; Filby, B; Glick, B R

    2000-07-28

    Transgenic tomato plants Lycopersicon esculentum (Solanaceae) cv. Heinz 902 expressing the bacterial gene 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase, under the transcriptional control of either two tandem 35S cauliflower mosaic virus promoters (constitutive expression), the rolD promoter from Agrobacterium rhizogenes (root specific expression) or the pathogenesis related PRB-1b promoter from tobacco, were compared to non-transgenic tomato plants in their ability to grow in the presence of Cd, Co, Cu, Mg, Ni, Pb, or Zn and to accumulate these metals. Parameters that were examined include metal concentration and ACC deaminase activity in both plant shoots and roots; root and shoot development; and leaf chlorophyll content. In general, transgenic tomato plants expressing ACC deaminase, especially those controlled by the PRB-1b promoter, acquired a greater amount of metal within the plant tissues, and were less subject to the deleterious effects of the metals on plant growth than were non-transgenic plants. PMID:10936659

  16. Transport of sup 14 C-IAA and sup 14 C-ACC within floral organs of Ipomoea nil

    SciTech Connect

    Kiss, H.G. ); Maurice, H.R. ); Koning, R.E. ); Daie, J. )

    1989-04-01

    The transport of {sup 14}C-IAA {sup 14}C-ACC from agarose donor blocks applied to I. nil filaments their recovery as {sup 14}C-accumulation into floral organs was examined. The accumulation of the isotopes in the corolla tissue was greater when {sup 14}C-ACC was applied than {sup 14}C-IAA in intact isolated flower buds. Greater levels of the isotopes accumulated in the pistil, with minimal levels in receptacle and calyx tissues from isolated buds. With intact buds, greater levels of the isotopes were recovered in pistil, calyx receptacle tissues. This study provides further evidence for the role of the filaments as transport vectors for IAA ACC for the production of ethylene.

  17. The effect of native and ACC deaminase-containing Azospirillum brasilense Cd1843 on the rooting of carnation cuttings.

    PubMed

    Li, Qiaosi; Saleh-Lakha, Saleema; Glick, Bernard R

    2005-06-01

    Carnation cuttings treated with non-transformed and 1-aminocyclopropane (ACC) deaminase-containing Azospirillum brasilense Cd1843 produced significantly more roots than untreated controls and fewer roots than cuttings treated with 0.1% indolebutyric acid (IBA). The roots produced by cuttings treated with ACC deaminase-containing Azospirillum brasilense Cd1843 were the longest roots resulting from any of the treatments, followed by non-transformed Azospirillum brasilense Cd1843, 0.1% IBA, and treatment with water. The results are interpreted in terms of a previously proposed model of bacterial promotion of plant growth by ACC deaminase and indoleacetic acid, and may have implications for the use of plant growth-promoting bacteria in the flower industry. PMID:16121231

  18. Characterization and expression profiles of MaACS and MaACO genes from mulberry (Morus alba L.)*

    PubMed Central

    Liu, Chang-ying; Lü, Rui-hua; Li, Jun; Zhao, Ai-chun; Wang, Xi-ling; Diane, Umuhoza; Wang, Xiao-hong; Wang, Chuan-hong; Yu, Ya-sheng; Han, Shu-mei; Lu, Cheng; Yu, Mao-de

    2014-01-01

    1-Aminocyclopropane-1-carboxylic acid synthase (ACS) and 1-aminocyclopropane-1-carboxylic acid oxidase (ACO) are encoded by multigene families and are involved in fruit ripening by catalyzing the production of ethylene throughout the development of fruit. However, there are no reports on ACS or ACO genes in mulberry, partly because of the limited molecular research background. In this study, we have obtained five ACS gene sequences and two ACO gene sequences from Morus Genome Database. Sequence alignment and phylogenetic analysis of MaACO1 and MaACO2 showed that their amino acids are conserved compared with ACO proteins from other species. MaACS1 and MaACS2 are type I, MaACS3 and MaACS4 are type II, and MaACS5 is type III, with different C-terminal sequences. Quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) expression analysis showed that the transcripts of MaACS genes were strongly expressed in fruit, and more weakly in other tissues. The expression of MaACO1 and MaACO2 showed different patterns in various mulberry tissues. MaACS and MaACO genes demonstrated two patterns throughout the development of mulberry fruit, and both of them were strongly up-regulated by abscisic acid (ABA) and ethephon. PMID:25001221

  19. Inducible nitric oxide synthase and inflammation.

    PubMed

    Salvemini, D; Marino, M H

    1998-01-01

    Nitric oxide (NO), derived from L-arginine (L-Arg) by the enzyme nitric oxide synthase (NOS), is involved in acute and chronic inflammatory events. In view of the complexity associated with the inflammatory response, the dissection of possible mechanisms by which NO modulates this response will be profitable in designing novel and more efficacious NOS inhibitors. In this review we describe the consequences associated with the induction of inducible nitric oxide synthase (iNOS) and its therapeutic implications. PMID:15991919

  20. Zonal Variations of Eddy Diffusivities in an ACC-like Channel: Discrete Transport Corridors.

    NASA Astrophysics Data System (ADS)

    Lazar, A.; Thompson, A. F.

    2014-12-01

    The meridional overturning circulation in a wind-driven re-entrant channel arises from a balance between an Eulerian mean overturning and an eddy overturning. These cancel to leading order in the Southern Ocean's Antarctic Circumpolar Current (ACC). An ACC-like flow, with realistic stratification, zonal transport and distributions of eddy kinetic energy, develops even when these two overturning components cancel completely. Many studies have noted that an enhancement of the Eulerian overturning circulation, which tends to steepen isopycnals, is balanced in part by an enhancement of the eddy circulation that relaxes isopycnal tilt. Thus the domain-averaged isopycnal slope and zonal transport are relatively insensitive to changes in wind forcing. However, the response of the system's mesoscale variability and eddy fluxes is not uniform throughout the domain. We present a process study of an idealized eddy-resolving ACC-like channel with negligible residual overturning to explore how the along-stream distribution of eddy characteristics establishes a balance between wind and eddy overturning circulations. For each simulation, we decompose the overturning circulation into mean, standing and transient components. As the surface wind stress increases, the standing component balances a larger portion of the mean overturning. This in turn leads to an increasing departure from zonally-symmetric eddy characteristics. A zonal-mean, or net, eddy diffusivity Κnet is defined as the eddy diffusivity required to exactly balance the mean overturning based on the zonal-mean isopycnal slope, s. This gives Κnet=τ/ρ0fs, where τ is the wind stress, ρ0 is a reference density and f is the Coriolis parameter. Κnet is compared to local eddy diffusivities, Κlocal, diagnosed directly from the divergent component of the eddy buoyancy flux divided by the local isopycnal slope. We find that with a simple topographic ridge and moderate wind forcing, along-stream averages of

  1. Acceleration of a Particle-in-Cell Code for Space Plasma Simulations with OpenACC

    NASA Astrophysics Data System (ADS)

    Peng, Ivy Bo; Markidis, Stefano; Vaivads, Andris; Vencels, Juris; Deca, Jan; Lapenta, Giovanni; Hart, Alistair; Laure, Erwin

    2015-04-01

    We simulate space plasmas with the Particle-in-cell (PIC) method that uses computational particles to mimic electrons and protons in solar wind and in Earth magnetosphere. The magnetic and electric fields are computed by solving the Maxwell's equations on a computational grid. In each PIC simulation step, there are four major phases: interpolation of fields to particles, updating the location and velocity of each particle, interpolation of particles to grids and solving the Maxwell's equations on the grid. We use the iPIC3D code, which was implemented in C++, using both MPI and OpenMP, for our case study. By November 2014, heterogeneous systems using hardware accelerators such as Graphics Processing Unit (GPUs) and the Many Integrated Core (MIC) coprocessors for high performance computing continue growth in the top 500 most powerful supercomputers world wide. Scientific applications for numerical simulations need to adapt to using accelerators to achieve portability and scalability in the coming exascale systems. In our work, we conduct a case study of using OpenACC to offload the computation intensive parts: particle mover and interpolation of particles to grids, in a massively parallel Particle-in-Cell simulation code, iPIC3D, to multi-GPU systems. We use MPI for inter-node communication for halo exchange and communicating particles. We identify the most promising parts suitable for GPUs accelerator by profiling using CrayPAT. We implemented manual deep copy to address the challenges of porting C++ classes to GPU. We document the necessary changes in the exiting algorithms to adapt for GPU computation. We present the challenges and findings as well as our methodology for porting a Particle-in-Cell code to multi-GPU systems using OpenACC. In this work, we will present the challenges, findings and our methodology of porting a Particle-in-Cell code for space applications as follows: We profile the iPIC3D code by Cray Performance Analysis Tool (CrayPAT) and identify

  2. AC power systems handbook

    SciTech Connect

    Whitaker, J.

    1991-01-01

    Transient disturbances are what headaches are made of. Whatever you call them-spikes, surges, are power bumps-they can take your equipment down and leave you with a complicated and expensive repair job. Protection against transient disturbances is a science that demands attention to detail. This book explains how the power distribution system works, what can go wrong with it, and how to protect a facility against abnormalities. system grounding and shielding are covered in detail. Each major method of transient protection is analyzed and its relative merits discussed. The book provides a complete look at the critical elements of the ac power system. Provides a complete look at the ac power system from generation to consumption. Discusses the mechanisms that produce transient disturbances and how to protect against them. Presents diagrams to facilitate system design. Covers new areas, such as the extent of the transient disturbance problem, transient protection options, and stand-by power systems.

  3. Unique animal prenyltransferase with monoterpene synthase activity

    NASA Astrophysics Data System (ADS)

    Gilg, Anna B.; Tittiger, Claus; Blomquist, Gary J.

    2009-06-01

    Monoterpenes are structurally diverse natural compounds that play an essential role in the chemical ecology of a wide array of organisms. A key enzyme in monoterpene biosynthesis is geranyl diphosphate synthase (GPPS). GPPS is an isoprenyl diphosphate synthase that catalyzes a single electrophilic condensation reaction between dimethylallyl diphosphate (C5) and isopentenyl diphosphate (C5) to produce geranyl diphosphate (GDP; C10). GDP is the universal precursor to all monoterpenes. Subsequently, monoterpene synthases are responsible for the transformation of GDP to a variety of acyclic, monocyclic, and bicyclic monoterpene products. In pheromone-producing male Ips pini bark beetles (Coleoptera: Scolytidae), the acyclic monoterpene myrcene is required for the production of the major aggregation pheromone component, ipsdienol. Here, we report monoterpene synthase activity associated with GPPS of I. pini. Enzyme assays were performed on recombinant GPPS to determine the presence of monoterpene synthase activity, and the reaction products were analyzed by coupled gas chromatography-mass spectrometry. The functionally expressed recombinant enzyme produced both GDP and myrcene, making GPPS of I. pini a bifunctional enzyme. This unique insect isoprenyl diphosphate synthase possesses the functional plasticity that is characteristic of terpene biosynthetic enzymes of plants, contributing toward the current understanding of product specificity of the isoprenoid pathway.

  4. Functional copper at the acetyl-CoA synthase active site

    PubMed Central

    Seravalli, Javier; Gu, Weiwei; Tam, Annie; Strauss, Erick; Begley, Tadhg P.; Cramer, Stephen P.; Ragsdale, Stephen W.

    2003-01-01

    The bifunctional CO dehydrogenase/acetyl-CoA synthase (CODH/ACS) plays a central role in the Wood–Ljungdahl pathway of autotrophic CO2 fixation. A recent structure of the Moorella thermoacetica enzyme revealed that the ACS active site contains a [4Fe-4S] cluster bridged to a binuclear Cu-Ni site. Here, biochemical and x-ray absorption spectroscopic (XAS) evidence is presented that the copper ion at the M. thermoacetica ACS active site is essential. Depletion of copper correlates with reduction in ACS activity and in intensity of the “NiFeC” EPR signal without affecting either the activity or the EPR spectroscopic properties associated with CODH. In contrast, Zn content is negatively correlated with ACS activity without any apparent relationship to CODH activity. Cu is also found in the methanogenic CODH/ACS from Methanosarcina thermophila. XAS studies are consistent with a distorted Cu(I)–S3 site in the fully active enzyme in solution. Cu extended x-ray absorption fine structure analysis indicates an average Cu–S bond length of 2.25 Å and a metal neighbor at 2.65 Å, consistent with the Cu–Ni distance observed in the crystal structure. XAS experiments in the presence of seleno-CoA reveal a Cu–S3Se environment with a 2.4-Å Se–Cu bond, strongly implicating a Cu–SCoA intermediate in the mechanism of acetyl-CoA synthesis. These results indicate an essential and functional role for copper in the CODH/ACS from acetogenic and methanogenic organisms. PMID:12589021

  5. Ceramide synthases in biomedical research.

    PubMed

    Cingolani, Francesca; Futerman, Anthony H; Casas, Josefina

    2016-05-01

    Sphingolipid metabolism consists of multiple metabolic pathways that converge upon ceramide, one of the key molecules among sphingolipids (SLs). In mammals, ceramide synthesis occurs via N-acylation of sphingoid backbones, dihydrosphingosine (dhSo) or sphingosine (So). The reaction is catalyzed by ceramide synthases (CerS), a family of enzymes with six different isoforms, with each one showing specificity towards a restricted group of acyl-CoAs, thus producing ceramides (Cer) and dihydroceramides (dhCer) with different fatty acid chain lengths. A large body of evidence documents the role of both So and dhSo as bioactive molecules, as well as the involvement of dhCer and Cer in physiological and pathological processes. In particular, the fatty acid composition of Cer has different effects in cell biology and in the onset and progression of different diseases. Therefore, modulation of CerS activity represents an attractive target in biomedical research and in finding new treatment modalities. In this review, we discuss functional, structural and biochemical features of CerS and examine CerS inhibitors that are currently available. PMID:26248326

  6. [2013 Guidelines ACC/AHA cardiovascular risk. Incomplete evidence and failed attempt at simplification].

    PubMed

    Corral, Pablo

    2015-01-01

    After almost a decade, finally Guidelines for the management of hypercholesterolemia in adults by the AHA/ACC were published. The substantial change in the paradigm of this new recommendation is the treatment decision basically statin, based on a recalculation of cardiovascular risk. Four groups were identified and based on them different statins indication, according to the power applied. As is apparent, have been used only randomized clinical trials (RCT) as the sole basis for the drafting of these new guidelines. Two basic issues are reviewed and revised in the following article: leaving aside other types of evidence to generate the recommendation and on the other hand the attempt to simplify the interpretation and management of this condition. We stress the need for any recommendation to clinical reasoning to interpret different scenarios involved in each patient. PMID:25496959

  7. Reward sensitivity modulates brain activity in the prefrontal cortex, ACC and striatum during task switching.

    PubMed

    Fuentes-Claramonte, Paola; Ávila, César; Rodríguez-Pujadas, Aina; Ventura-Campos, Noelia; Bustamante, Juan C; Costumero, Víctor; Rosell-Negre, Patricia; Barrós-Loscertales, Alfonso

    2015-01-01

    Current perspectives on cognitive control acknowledge that individual differences in motivational dispositions may modulate cognitive processes in the absence of reward contingencies. This work aimed to study the relationship between individual differences in Behavioral Activation System (BAS) sensitivity and the neural underpinnings involved in processing a switching cue in a task-switching paradigm. BAS sensitivity was hypothesized to modulate brain activity in frontal regions, ACC and the striatum. Twenty-eight healthy participants underwent fMRI while performing a switching task, which elicited activity in fronto-striatal regions during the processing of the switch cue. BAS sensitivity was negatively associated with activity in the lateral prefrontal cortex, anterior cingulate cortex and the ventral striatum. Combined with previous results, our data indicate that BAS sensitivity modulates the neurocognitive processes involved in task switching in a complex manner depending on task demands. Therefore, individual differences in motivational dispositions may influence cognitive processing in the absence of reward contingencies. PMID:25875640

  8. Reward Sensitivity Modulates Brain Activity in the Prefrontal Cortex, ACC and Striatum during Task Switching

    PubMed Central

    Fuentes-Claramonte, Paola; Ávila, César; Rodríguez-Pujadas, Aina; Ventura-Campos, Noelia; Bustamante, Juan C.; Costumero, Víctor; Rosell-Negre, Patricia; Barrós-Loscertales, Alfonso

    2015-01-01

    Current perspectives on cognitive control acknowledge that individual differences in motivational dispositions may modulate cognitive processes in the absence of reward contingencies. This work aimed to study the relationship between individual differences in Behavioral Activation System (BAS) sensitivity and the neural underpinnings involved in processing a switching cue in a task-switching paradigm. BAS sensitivity was hypothesized to modulate brain activity in frontal regions, ACC and the striatum. Twenty-eight healthy participants underwent fMRI while performing a switching task, which elicited activity in fronto-striatal regions during the processing of the switch cue. BAS sensitivity was negatively associated with activity in the lateral prefrontal cortex, anterior cingulate cortex and the ventral striatum. Combined with previous results, our data indicate that BAS sensitivity modulates the neurocognitive processes involved in task switching in a complex manner depending on task demands. Therefore, individual differences in motivational dispositions may influence cognitive processing in the absence of reward contingencies. PMID:25875640

  9. Sequencing of allotetraploid cotton (Gossypium hirsutum L. acc. TM-1) provides a resource for fiber improvement.

    PubMed

    Zhang, Tianzhen; Hu, Yan; Jiang, Wenkai; Fang, Lei; Guan, Xueying; Chen, Jiedan; Zhang, Jinbo; Saski, Christopher A; Scheffler, Brian E; Stelly, David M; Hulse-Kemp, Amanda M; Wan, Qun; Liu, Bingliang; Liu, Chunxiao; Wang, Sen; Pan, Mengqiao; Wang, Yangkun; Wang, Dawei; Ye, Wenxue; Chang, Lijing; Zhang, Wenpan; Song, Qingxin; Kirkbride, Ryan C; Chen, Xiaoya; Dennis, Elizabeth; Llewellyn, Danny J; Peterson, Daniel G; Thaxton, Peggy; Jones, Don C; Wang, Qiong; Xu, Xiaoyang; Zhang, Hua; Wu, Huaitong; Zhou, Lei; Mei, Gaofu; Chen, Shuqi; Tian, Yue; Xiang, Dan; Li, Xinghe; Ding, Jian; Zuo, Qiyang; Tao, Linna; Liu, Yunchao; Li, Ji; Lin, Yu; Hui, Yuanyuan; Cao, Zhisheng; Cai, Caiping; Zhu, Xiefei; Jiang, Zhi; Zhou, Baoliang; Guo, Wangzhen; Li, Ruiqiang; Chen, Z Jeffrey

    2015-05-01

    Upland cotton is a model for polyploid crop domestication and transgenic improvement. Here we sequenced the allotetraploid Gossypium hirsutum L. acc. TM-1 genome by integrating whole-genome shotgun reads, bacterial artificial chromosome (BAC)-end sequences and genotype-by-sequencing genetic maps. We assembled and annotated 32,032 A-subgenome genes and 34,402 D-subgenome genes. Structural rearrangements, gene loss, disrupted genes and sequence divergence were more common in the A subgenome than in the D subgenome, suggesting asymmetric evolution. However, no genome-wide expression dominance was found between the subgenomes. Genomic signatures of selection and domestication are associated with positively selected genes (PSGs) for fiber improvement in the A subgenome and for stress tolerance in the D subgenome. This draft genome sequence provides a resource for engineering superior cotton lines. PMID:25893781

  10. The tomato terpene synthase gene family.

    PubMed

    Falara, Vasiliki; Akhtar, Tariq A; Nguyen, Thuong T H; Spyropoulou, Eleni A; Bleeker, Petra M; Schauvinhold, Ines; Matsuba, Yuki; Bonini, Megan E; Schilmiller, Anthony L; Last, Robert L; Schuurink, Robert C; Pichersky, Eran

    2011-10-01

    Compounds of the terpenoid class play numerous roles in the interactions of plants with their environment, such as attracting pollinators and defending the plant against pests. We show here that the genome of cultivated tomato (Solanum lycopersicum) contains 44 terpene synthase (TPS) genes, including 29 that are functional or potentially functional. Of these 29 TPS genes, 26 were expressed in at least some organs or tissues of the plant. The enzymatic functions of eight of the TPS proteins were previously reported, and here we report the specific in vitro catalytic activity of 10 additional tomato terpene synthases. Many of the tomato TPS genes are found in clusters, notably on chromosomes 1, 2, 6, 8, and 10. All TPS family clades previously identified in angiosperms are also present in tomato. The largest clade of functional TPS genes found in tomato, with 12 members, is the TPS-a clade, and it appears to encode only sesquiterpene synthases, one of which is localized to the mitochondria, while the rest are likely cytosolic. A few additional sesquiterpene synthases are encoded by TPS-b clade genes. Some of the tomato sesquiterpene synthases use z,z-farnesyl diphosphate in vitro as well, or more efficiently than, the e,e-farnesyl diphosphate substrate. Genes encoding monoterpene synthases are also prevalent, and they fall into three clades: TPS-b, TPS-g, and TPS-e/f. With the exception of two enzymes involved in the synthesis of ent-kaurene, the precursor of gibberellins, no other tomato TPS genes could be demonstrated to encode diterpene synthases so far. PMID:21813655

  11. Terpene synthases are widely distributed in bacteria

    PubMed Central

    Yamada, Yuuki; Kuzuyama, Tomohisa; Komatsu, Mamoru; Shin-ya, Kazuo; Omura, Satoshi; Cane, David E.; Ikeda, Haruo

    2015-01-01

    Odoriferous terpene metabolites of bacterial origin have been known for many years. In genome-sequenced Streptomycetaceae microorganisms, the vast majority produces the degraded sesquiterpene alcohol geosmin. Two minor groups of bacteria do not produce geosmin, with one of these groups instead producing other sesquiterpene alcohols, whereas members of the remaining group do not produce any detectable terpenoid metabolites. Because bacterial terpene synthases typically show no significant overall sequence similarity to any other known fungal or plant terpene synthases and usually exhibit relatively low levels of mutual sequence similarity with other bacterial synthases, simple correlation of protein sequence data with the structure of the cyclized terpene product has been precluded. We have previously described a powerful search method based on the use of hidden Markov models (HMMs) and protein families database (Pfam) search that has allowed the discovery of monoterpene synthases of bacterial origin. Using an enhanced set of HMM parameters generated using a training set of 140 previously identified bacterial terpene synthase sequences, a Pfam search of 8,759,463 predicted bacterial proteins from public databases and in-house draft genome data has now revealed 262 presumptive terpene synthases. The biochemical function of a considerable number of these presumptive terpene synthase genes could be determined by expression in a specially engineered heterologous Streptomyces host and spectroscopic identification of the resulting terpene products. In addition to a wide variety of terpenes that had been previously reported from fungal or plant sources, we have isolated and determined the complete structures of 13 previously unidentified cyclic sesquiterpenes and diterpenes. PMID:25535391

  12. Properties of phosphorylated thymidylate synthase.

    PubMed

    Frączyk, Tomasz; Ruman, Tomasz; Wilk, Piotr; Palmowski, Paweł; Rogowska-Wrzesinska, Adelina; Cieśla, Joanna; Zieliński, Zbigniew; Nizioł, Joanna; Jarmuła, Adam; Maj, Piotr; Gołos, Barbara; Wińska, Patrycja; Ostafil, Sylwia; Wałajtys-Rode, Elżbieta; Shugar, David; Rode, Wojciech

    2015-12-01

    Thymidylate synthase (TS) may undergo phosphorylation endogenously in mammalian cells, and as a recombinant protein expressed in bacterial cells, as indicated by the reaction of purified enzyme protein with Pro-Q® Diamond Phosphoprotein Gel Stain (PGS). With recombinant human, mouse, rat, Trichinella spiralis and Caenorhabditis elegans TSs, expressed in Escherichia coli, the phosphorylated, compared to non-phosphorylated recombinant enzyme forms, showed a decrease in Vmax(app), bound their cognate mRNA (only rat enzyme studied), and repressed translation of their own and several heterologous mRNAs (human, rat and mouse enzymes studied). However, attempts to determine the modification site(s), whether endogenously expressed in mammalian cells, or recombinant proteins, did not lead to unequivocal results. Comparative ESI-MS/analysis of IEF fractions of TS preparations from parental and FdUrd-resistant mouse leukemia L1210 cells, differing in sensitivity to inactivation by FdUMP, demonstrated phosphorylation of Ser(10) and Ser(16) in the resistant enzyme only, although PGS staining pointed to the modification of both L1210 TS proteins. The TS proteins phosphorylated in bacterial cells were shown by (31)P NMR to be modified only on histidine residues, like potassium phosphoramidate (KPA)-phosphorylated TS proteins. NanoLC-MS/MS, enabling the use of CID and ETD peptide fragmentation methods, identified several phosphohistidine residues, but certain phosphoserine and phosphothreonine residues were also implicated. Molecular dynamics studies, based on the mouse TS crystal structure, allowed one to assess potential of several phosphorylated histidine residues to affect catalytic activity, the effect being phosphorylation site dependent. PMID:26315778

  13. The human ACC2 CT-domain C-terminus is required for full functionality and has a novel twist

    SciTech Connect

    Madauss, Kevin P.; Burkhart, William A.; Consler, Thomas G.; Cowan, David J.; Gottschalk, William K.; Miller, Aaron B; Short, Steven A.; Tran, Thuy B.; Williams, Shawn P.

    2009-06-15

    Inhibition of acetyl-CoA carboxylase (ACC) may prevent lipid-induced insulin resistance and type 2 diabetes, making the enzyme an attractive pharmaceutical target. Although the enzyme is highly conserved amongst animals, only the yeast enzyme structure is available for rational drug design. The use of biophysical assays has permitted the identification of a specific C-terminal truncation of the 826-residue human ACC2 carboxyl transferase (CT) domain that is both functionally competent to bind inhibitors and crystallizes in their presence. This C-terminal truncation led to the determination of the human ACC2 CT domain-CP-640186 complex crystal structure, which revealed distinctions from the yeast-enzyme complex. The human ACC2 CT-domain C-terminus is comprised of three intertwined -helices that extend outwards from the enzyme on the opposite side to the ligand-binding site. Differences in the observed inhibitor conformation between the yeast and human structures are caused by differing residues in the binding pocket.

  14. Improved Performance of an Air Cooled Condenser (ACC) Using SPX Wind Guide Technology at Coal-Based Thermoelectric Power Plants

    SciTech Connect

    Ken Mortensen

    2010-12-31

    This project added a new airflow enhancement technology to an existing ACC cooling process at a selected coal power plant. Airflow parameters and efficiency improvement for the main plant cooling process using the applied technology were determined and compared with the capabilities of existing systems. The project required significant planning and pre-test execution in order to reach the required Air Cooled Condenser system configuration for evaluation. A host Power Plant ACC system had to be identified, agreement finalized, and addition of the SPX ACC Wind Guide Technology completed on that site. Design of the modification, along with procurement, fabrication, instrumentation, and installation of the new airflow enhancement technology were executed. Baseline and post-modification cooling system data was collected and evaluated. The improvement of ACC thermal performance after SPX wind guide installation was clear. Testing of the improvement indicates there is a 5% improvement in heat transfer coefficient in high wind conditions and 1% improvement at low wind speed. The benefit increased with increasing wind speed. This project was completed on schedule and within budget.

  15. 24 CFR 982.102 - Allocation of budget authority for renewal of expiring consolidated ACC funding increments.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 24 Housing and Urban Development 4 2013-04-01 2013-04-01 false Allocation of budget authority for renewal of expiring consolidated ACC funding increments. 982.102 Section 982.102 Housing and Urban Development REGULATIONS RELATING TO HOUSING AND URBAN DEVELOPMENT (CONTINUED) OFFICE OF ASSISTANT...

  16. 24 CFR 982.102 - Allocation of budget authority for renewal of expiring consolidated ACC funding increments.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 4 2014-04-01 2014-04-01 false Allocation of budget authority for renewal of expiring consolidated ACC funding increments. 982.102 Section 982.102 Housing and Urban Development REGULATIONS RELATING TO HOUSING AND URBAN DEVELOPMENT (CONTINUED) OFFICE OF ASSISTANT...

  17. 24 CFR 982.102 - Allocation of budget authority for renewal of expiring consolidated ACC funding increments.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 24 Housing and Urban Development 4 2012-04-01 2012-04-01 false Allocation of budget authority for renewal of expiring consolidated ACC funding increments. 982.102 Section 982.102 Housing and Urban Development REGULATIONS RELATING TO HOUSING AND URBAN DEVELOPMENT (CONTINUED) OFFICE OF ASSISTANT...

  18. 24 CFR 982.102 - Allocation of budget authority for renewal of expiring consolidated ACC funding increments.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 4 2011-04-01 2011-04-01 false Allocation of budget authority for renewal of expiring consolidated ACC funding increments. 982.102 Section 982.102 Housing and Urban Development REGULATIONS RELATING TO HOUSING AND URBAN DEVELOPMENT (CONTINUED) OFFICE OF ASSISTANT...

  19. 24 CFR 982.102 - Allocation of budget authority for renewal of expiring consolidated ACC funding increments.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 4 2010-04-01 2010-04-01 false Allocation of budget authority for renewal of expiring consolidated ACC funding increments. 982.102 Section 982.102 Housing and Urban Development Regulations Relating to Housing and Urban Development (Continued) OFFICE OF ASSISTANT...

  20. Characterization of ACC deaminase gene in Pseudomonas entomophila strain PS-PJH isolated from the rhizosphere soil.

    PubMed

    Kamala-Kannan, Seralathan; Lee, Kui-Jae; Park, Seung-Moon; Chae, Jong-Chan; Yun, Bong-Sik; Lee, Yong Hoon; Park, Yool-Jin; Oh, Byung-Taek

    2010-04-01

    The enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase cleaves the ethylene precursor ACC into alpha-ketobutyrate and ammonia. The decreased level of ethylene allows the plant to be more resistant to a wide environmental stress including plant pathogens. In the present study, we characterized the ACC deaminase activity of a Pseudomonas entomophila strain PS-PJH isolated from the red pepper rhizosphere region of red pepper grown at Jinan, Korea. The isolate produced 23.8 +/- 0.4 micromol of alpha-ketobutyrate/mg of protein/h during ACC deamination under in vitro conditions. Polymerase chain reaction for acdS gene showed that the isolated P. entomophila strain PS-PJH carry sequences similar to the known acdS genes. Results of the multiple sequence alignment revealed >99% identity (nucleotide and amino acid) with acdS gene of Pseudomonas putida strains AM15 and UW4. The isolated bacteria promoted 43.3 and 34.1% of growth in Raphanus sativus and Lactuca sativa plants, respectively. Based on the 16S-23S internal transcribed spacer region sequences, the isolate was identified as P. entomophila. To the best of our knowledge this is the first study to report the acdS gene in P. entomophila. PMID:20082369

  1. Basement membrane heparan sulfate proteoglycan (perlecan) synthesized by ACC3, adenoid cystic carcinoma cells of human salivary gland origin.

    PubMed

    Kimura, S; Cheng, J; Toyoshima, K; Oda, K; Saku, T

    1999-02-01

    The biosynthesis of basement membrane heparan sulfate proteoglycan (HSPG), known as perlecan, in ACC3 cells established from a adenoid cystic carcinoma of the human salivary gland was studied using metabolic labeling and immunoprecipitation with discriminative antibodies specific for HSPG core protein. Treatment of immunoprecipitated HSPG with HNO2, heparitinase, and chondroitinase ABC revealed that ACC3 cells synthesized HSPG molecules composed of 470-kDa core protein and heparan sulfate but not of chondroitin sulfate. The core protein was shown to contain complex type N-linked oligosaccharides by digestion with N-glycanase and endoglycosidase H. Pulse-chase experiments showed that the mature form of HSPG was formed in the cells in 30 min and released into the medium thereafter. Degradation of HSPG was also found in the chase period of 3 h. In time course experiments, HSPG was found to be synthesized maximally at day 4 after plating, deposited in the cell layer maximally at day 6, and secreted maximally at day 8. This was also confirmed by immunofluorescence, Northern blotting, and in-situ hybridization. The results indicate that ACC3 cells synthesize, secrete and degrade basement membrane type HSPG, which is analogous to those produced by other cell types, and that the biosynthesis and secretion of HSPG in ACC3 cells are strictly regulated by the cell growth, that may be reflected in the characteristic histology of adenoid cystic carcinomas. PMID:9990141

  2. Implementation and efficiency analysis of parallel computation using OpenACC: a case study using flow field simulations

    NASA Astrophysics Data System (ADS)

    Zhang, Shanghong; Yuan, Rui; Wu, Yu; Yi, Yujun

    2016-01-01

    The Open Accelerator (OpenACC) application programming interface is a relatively new parallel computing standard. In this paper, particle-based flow field simulations are examined as a case study of OpenACC parallel computation. The parallel conversion process of the OpenACC standard is explained, and further, the performance of the flow field parallel model is analysed using different directive configurations and grid schemes. With careful implementation and optimisation of the data transportation in the parallel algorithm, a speedup factor of 18.26× is possible. In contrast, a speedup factor of just 11.77× was achieved with the conventional Open Multi-Processing (OpenMP) parallel mode on a 20-kernel computer. These results demonstrate that optimised feature settings greatly influence the degree of speedup, and models involving larger numbers of calculations exhibit greater efficiency and higher speedup factors. In addition, the OpenACC parallel mode is found to have good portability, making it easy to implement parallel computation from the original serial model.

  3. Sound the Alarm: The Effect of Narcissism on Retaliatory Aggression Is Moderated by dACC Reactivity to Rejection.

    PubMed

    Chester, David S; DeWall, C Nathan

    2016-06-01

    Narcissists behave aggressively when their egos are threatened by interpersonal insults. This effect has been explained in terms of narcissists' motivation to reduce the discrepancy between their grandiose self and its threatened version, though no research has directly tested this hypothesis. If this notion is true, the link between narcissism and retaliatory aggression should be moderated by neural structures that subserve discrepancy detection, such as the dorsal anterior cingulate cortex (dACC). This study tested the hypothesis that narcissism would only predict greater retaliatory aggression in response to social rejection when the dACC was recruited by the threat. Thirty participants (15 females; Mage  = 18.86, SD = 1.25; 77% White) completed a trait narcissism inventory, were socially accepted and then rejected while undergoing fMRI, and then could behave aggressively toward one of the rejecters by blasting him or her with unpleasant noise. When narcissists displayed greater dACC activation during rejection, they behaved aggressively. But there was only a weak or nonsignificant relation between narcissism and aggression among participants with a blunted dACC response. Narcissism's role in aggressive retaliation to interpersonal threats is likely determined by the extent to which the brain's discrepancy detector registers the newly created gap between the grandiose and threatened selves. PMID:25564936

  4. Expression of recombinant AccMRJP1 protein from royal jelly of Chinese honeybee in Pichia pastoris and its proliferation activity in an insect cell line

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Main royal jelly protein 1 (MRJP1) is the most abundant member of the main royal jelly protein (MRJP) family among honeybees. Mature MRJP1 cDNA of the Chinese honeybee (Apis cerana cerana MRJP1, or AccMRJP1) was expressed in Pichia pastoris. SDS-PAGE showed that recombinant AccMRJP1 was identical in...

  5. Aromatic Polyketide Synthases (Purification, Characterization, and Antibody Development to Benzalacetone Synthase from Raspberry Fruits).

    PubMed Central

    Borejsza-Wysocki, W.; Hrazdina, G.

    1996-01-01

    p-Hydroxyphenylbutan-2-one, the characteristic aroma compound of raspberries (Rubus idaeus L.), is synthesized from p-coumaryl-coenzyme A and malonyl-coenzyme A in a two-step reaction sequence that is catalyzed by benzalacetone synthase and benzalacetone reductase (W. Borejsza-Wysocki and G. Hrazdina [1994] Phytochemistry 35: 623-628). Benzalacetone synthase condenses one malonate with p-coumarate to form the pathway intermediate p-hydroxyphenylbut-3-ene-2-one (p-hydroxybenzalacetone) in a reaction that is similar to those catalyzed by chalcone and stilbene synthases. We have obtained an enzyme preparation from ripe raspberries that was preferentially enriched in benzalacetone synthase (approximately 170-fold) over chalcone synthase (approximately 14-fold) activity. This preparation was used to characterize benzalacetone synthase and to develop polyclonal antibodies in rabbits. Benzalacetone synthase showed similarity in its molecular properties to chalcone synthase but differed distinctly in its substrate specificity, response to 2-mercaptoethanol and ethylene glycol, and induction in cell-suspension cultures. The product of the enzyme, p-hydroxybenzalacetone, inhibited mycelial growth of the raspberry pathogen Phytophthora fragariae var rubi at 250 [mu]M. We do not know whether the dual activity in the benzalacetone synthase preparation is the result of a bifunctional enzyme or is caused by contamination with chalcone synthase that was also present. The rapid induction of the enzyme in cell-suspension cultures upon addition of yeast extract and the toxicity of its product, p-hydroxybenzalacetone, to phytopathogenic fungi also suggest that the pathway may be part of a plant defense response. PMID:12226219

  6. Distribution of Callose Synthase, Cellulose Synthase, and Sucrose Synthase in Tobacco Pollen Tube Is Controlled in Dissimilar Ways by Actin Filaments and Microtubules1[W

    PubMed Central

    Cai, Giampiero; Faleri, Claudia; Del Casino, Cecilia; Emons, Anne Mie C.; Cresti, Mauro

    2011-01-01

    Callose and cellulose are fundamental components of the cell wall of pollen tubes and are probably synthesized by distinct enzymes, callose synthase and cellulose synthase, respectively. We examined the distribution of callose synthase and cellulose synthase in tobacco (Nicotiana tabacum) pollen tubes in relation to the dynamics of actin filaments, microtubules, and the endomembrane system using specific antibodies to highly conserved peptide sequences. The role of the cytoskeleton and membrane flow was investigated using specific inhibitors (latrunculin B, 2,3-butanedione monoxime, taxol, oryzalin, and brefeldin A). Both enzymes are associated with the plasma membrane, but cellulose synthase is present along the entire length of pollen tubes (with a higher concentration at the apex) while callose synthase is located in the apex and in distal regions. In longer pollen tubes, callose synthase accumulates consistently around callose plugs, indicating its involvement in plug synthesis. Actin filaments and endomembrane dynamics are critical for the distribution of callose synthase and cellulose synthase, showing that enzymes are transported through Golgi bodies and/or vesicles moving along actin filaments. Conversely, microtubules appear to be critical in the positioning of callose synthase in distal regions and around callose plugs. In contrast, cellulose synthases are only partially coaligned with cortical microtubules and unrelated to callose plugs. Callose synthase also comigrates with tubulin by Blue Native-polyacrylamide gel electrophoresis. Membrane sucrose synthase, which expectedly provides UDP-glucose to callose synthase and cellulose synthase, binds to actin filaments depending on sucrose concentration; its distribution is dependent on the actin cytoskeleton and the endomembrane system but not on microtubules. PMID:21205616

  7. An investigation into eukaryotic pseudouridine synthases.

    PubMed

    King, Ross D; Lu, Chuan

    2014-08-01

    A common post-transcriptional modification of RNA is the conversion of uridine to its isomer pseudouridine. We investigated the biological significance of eukaryotic pseudouridine synthases using the yeast Saccharomyces cerevisiae. We conducted a comprehensive statistical analysis on growth data from automated perturbation (gene deletion) experiments, and used bi-logistic curve analysis to characterise the yeast phenotypes. The deletant strains displayed different alteration in growth properties, including in some cases enhanced growth and/or biphasic growth curves not seen in wild-type strains under matched conditions. These results demonstrate that disrupting pseudouridine synthases can have a significant qualitative effect on growth. We further investigated the significance of post-transcriptional pseudouridine modification through investigation of the scientific literature. We found that (1) In Toxoplasma gondii, a pseudouridine synthase gene is critical in cellular differentiation between the two asexual forms: Tachyzoites and bradyzoites; (2) Mutation of pseudouridine synthase genes has also been implicated in human diseases (mitochondrial myopathy and sideroblastic anemia (MLASA); dyskeratosis congenita). Taken together, these results are consistent with pseudouridine synthases having a Gene Ontology function of "biological regulation". PMID:25152040

  8. Doctors’ knowledge, attitudes, and compliance with 2013 ACC/AHA guidelines for prevention of atherosclerotic cardiovascular disease in Singapore

    PubMed Central

    Setia, Sajita; Fung, Selwyn Sze-Wang; Waters, David D

    2015-01-01

    Purpose There is an unmet need for strategies to prevent atherosclerotic cardiovascular disease in Singapore. The main objective of this study was to investigate Singapore physicians’ response to the 2013 American College of Cardiology and American Heart Association (ACC/AHA) guidelines for treatment of cholesterol and their impact on clinical practice. Methods This survey was conducted in two stages, qualitative and quantitative. Physicians were initially screened on the basis of an initial screener questionnaire, and eligible physicians were then included in the study. Results Qualitative (n=19) and quantitative (n=66) surveys were completed by eligible physicians from Singapore. Physicians were less familiar with the 2013 ACC/AHA guidelines (35%) as compared with the Singapore Ministry of Health (MoH) lipid guidelines 2006 (49%). Of the physicians whose opinion was sought on the ACC/AHA guidelines, more than 50% disagreed with the definition of high-, moderate-, and low-intensity statin therapy; recommendation of atorvastatin 40–80 mg and rosuvastatin 20–40 mg as medications for high-intensity statin therapy; and classification of individuals who would benefit from moderate- to high-intensity statin therapy. Most physicians assumed that Asians may be intolerant to high-intensity statin therapy. Conclusion Although embracing the 2013 ACC/AHA guidelines in clinical practice is expected to provide better clinical care to patients, our study revealed high reluctance by physicians, especially in the use of high-dose statins. However, ACC/AHA guidelines can be easily adopted in Asia as there is a wealth of data available for atorvastatin in primary and secondary prevention of atherosclerotic cardiovascular disease with similar efficacy and safety profiles in the white and Asian populations. PMID:26082642

  9. {alpha}-Lipoic acid prevents lipotoxic cardiomyopathy in acyl CoA-synthase transgenic mice

    SciTech Connect

    Lee, Young; Naseem, R. Haris; Park, Byung-Hyun; Garry, Daniel J.; Richardson, James A.; Schaffer, Jean E.; Unger, Roger H. . E-mail: roger.unger@utsouthwestern.edu

    2006-05-26

    {alpha}-Lipoic acid ({alpha}-LA) mimics the hypothalamic actions of leptin on food intake, energy expenditure, and activation of AMP-activated protein kinase (AMPK). To determine if, like leptin, {alpha}-LA protects against cardiac lipotoxicity, {alpha}-LA was fed to transgenic mice with cardiomyocyte-specific overexpression of the acyl CoA synthase (ACS) gene. Untreated ACS-transgenic mice died prematurely with increased triacylglycerol content and dilated cardiomyopathy, impaired systolic function and myofiber disorganization, apoptosis, and interstitial fibrosis on microscopy. In {alpha}-LA-treated ACS-transgenic mice heart size, echocardiogram and TG content were normal. Plasma TG fell 50%, hepatic-activated phospho-AMPK rose 6-fold, sterol regulatory element-binding protein-1c declined 50%, and peroxisome proliferator-activated receptor-{gamma} cofactor-1{alpha} mRNA rose 4-fold. Since food restriction did not prevent lipotoxicity, we conclude that {alpha}-LA treatment, like hyperleptinemia, protects the heart of ACS-transgenic mice from lipotoxicity.

  10. Transcriptional modulation of squalene synthase genes in barley treated with PGPR

    PubMed Central

    Yousaf, Anam; Qadir, Abdul; Anjum, Tehmina; Ahmad, Aqeel

    2015-01-01

    Phytosterol contents and food quality of plant produce is directly associated with transcription of gene squalene synthase (SS). In current study, barley plants were treated with different rhizobacterial strains under semi controlled (27 ± 3°C) greenhouse conditions in order to modulate expression of SS gene. Plant samples were analyzed through semi-quantitative PCR to evaluate effect of rhizobacterial application on transcriptional status of SS. Results revealed that among four SS genes (i.e., SSA, SS1, SS2, and SS3), the most expressive gene was SSA; while, SS2 was screened out as the second best induced gene due to Acetobacter aceti. The most efficient bacterial strain which recorded maximum gene expression was A. aceti AC8. Moreover, AC7 was reported as the least efficient bacterial species for inducing SS gene expression. AC8 enhanced the share of SSA and SS2 up to 43 and 31%, respectively. The study also described ribosomal sequence of the most efficient bacterial strain AC8, which was used to determine its phylogenetic relationships with other microbial strains. The study would be helpful to improve quality of plant produce by modulating transcription of SS genes. PMID:26388880

  11. Transcriptional modulation of squalene synthase genes in barley treated with PGPR.

    PubMed

    Yousaf, Anam; Qadir, Abdul; Anjum, Tehmina; Ahmad, Aqeel

    2015-01-01

    Phytosterol contents and food quality of plant produce is directly associated with transcription of gene squalene synthase (SS). In current study, barley plants were treated with different rhizobacterial strains under semi controlled (27 ± 3°C) greenhouse conditions in order to modulate expression of SS gene. Plant samples were analyzed through semi-quantitative PCR to evaluate effect of rhizobacterial application on transcriptional status of SS. Results revealed that among four SS genes (i.e., SSA, SS1, SS2, and SS3), the most expressive gene was SSA; while, SS2 was screened out as the second best induced gene due to Acetobacter aceti. The most efficient bacterial strain which recorded maximum gene expression was A. aceti AC8. Moreover, AC7 was reported as the least efficient bacterial species for inducing SS gene expression. AC8 enhanced the share of SSA and SS2 up to 43 and 31%, respectively. The study also described ribosomal sequence of the most efficient bacterial strain AC8, which was used to determine its phylogenetic relationships with other microbial strains. The study would be helpful to improve quality of plant produce by modulating transcription of SS genes. PMID:26388880

  12. Effects of wintertime fasting and seasonal adaptation on AMPK and ACC in hypothalamus, adipose tissue and liver of the raccoon dog (Nyctereutes procyonoides).

    PubMed

    Kinnunen, Sanni; Mänttäri, Satu; Herzig, Karl-Heinz; Nieminen, Petteri; Mustonen, Anne-Mari; Saarela, Seppo

    2016-02-01

    The raccoon dog (Nyctereutes procyonoides) is a canid with autumnal fattening and passive wintering strategy. We examined the effects of wintertime fasting and seasonality on AMP-activated protein kinase (AMPK), a regulator of metabolism, and its target, acetyl-CoA carboxylase (ACC) on the species. Twelve farmed raccoon dogs (eleven females/one male) were divided into two groups: half were fasted for ten weeks in December-March (winter fasted) and the others were fed ad libitum (winter fed). A third group (autumn fed, eight females) was fed ad libitum and sampled in December. Total AMPK, ACC and their phosphorylated forms (pAMPK, pACC) were measured from hypothalamus, liver, intra-abdominal (iWAT) and subcutaneous white adipose tissues (sWAT). The fasted animals lost 32% and the fed 20% of their body mass. Hypothalamic AMPK expression was lower and pACC levels higher in the winter groups compared to the autumn fed group. Liver pAMPK was lower in the winter fasted group, with consistently decreased ACC and pACC. AMPK and pAMPK were down-regulated in sWAT and iWAT of both winter groups, with a parallel decline in pACC in sWAT. The responses of AMPK and ACC to fasting were dissimilar to the effects observed previously in non-seasonal mammals and hibernators. Differences between the winter fed and autumn fed groups indicate that the functions of AMPK and ACC could be regulated in a season-dependent manner. Furthermore, the distinctive effects of prolonged fasting and seasonal adaptation on AMPK-ACC pathway could contribute to the wintering strategy of the raccoon dog. PMID:26603554

  13. Successful treatment of c-kit-positive metastatic Adenoid Cystic Carcinoma (ACC) with a combination of curcumin plus imatinib: A case report.

    PubMed

    Demiray, M; Sahinbas, H; Atahan, S; Demiray, H; Selcuk, D; Yildirim, I; Atayoglu, A T

    2016-08-01

    Adenoid cystic carcinoma (ACC) is an aggressive malignant neoplasm of the secretory glands. Conventional chemotherapy has poor effectiveness against metastatic ACC. Thus, a novel effective therapy is needed against metastatic ACC. A majority of ACCs (up to 94%) express c-kit. Imatinib is monoclonal antibody with specific activity against c-kit but has not been found to be effective in treating patients with ACC in which c-kit is overexpressed and activated. The NF-κB and mTOR pathways have been shown that ubiquitously and concurrently activated, indicating that the inhibition of these pathways may represent a novel treatment approach for patients with ACC. Curcumin has been shown to inhibit NF-κB and NF-κB-related pathways. 43-year-old patient was diagnosed ACC from submandibular salivary gland. After complete resection of tumor adjuvant radiotherapy was initiated. Seven years later multiple lung metastases were detected and ACC was confirmed by re-biopsy. First-line chemotherapy failed. NF-κB and c-kit were overexpressed in the metastatic specimens. Therefore, we treated the patient with metastatic chemoresistant ACC with imatinib 400mg/day and intravenous curcumin 225mg/m(2) twice a week plus oral bioavailable curcumin Arantal(®) 2×84mg/day. At 24 months, we observed near complete anatomic and complete metabolic response. To our knowledge, this is the first report of a patient with a c-kit-positive ACC that is successfully treated with the combination of imatinib and curcumin in an integrative approach. PMID:27515884

  14. Identification of /sup 233/Ac

    SciTech Connect

    Chu, Y.Y.; Zhou, M.L.

    1983-09-01

    We report in this paper identification of the new isotope /sup 233/Ac. Uranium targets were irradiated with 28 GeV protons; after rapid retrieval of the target and separation of actinium from thorium, /sup 233/Ac was allowed to decay into the known /sup 233/Th daughter. Exhaustive chemical purification was employed to permit the identification of /sup 233/Th via its characteristic ..gamma.. radiations. The half-life derived for /sup 233/Ac from several experiments is 2.3 +- 0.3 min. The production cross section for /sup 233/Ac is 100 ..mu..b.

  15. AC resistance measuring instrument

    DOEpatents

    Hof, P.J.

    1983-10-04

    An auto-ranging AC resistance measuring instrument for remote measurement of the resistance of an electrical device or circuit connected to the instrument includes a signal generator which generates an AC excitation signal for application to a load, including the device and the transmission line, a monitoring circuit which provides a digitally encoded signal representing the voltage across the load, and a microprocessor which operates under program control to provide an auto-ranging function by which range resistance is connected in circuit with the load to limit the load voltage to an acceptable range for the instrument, and an auto-compensating function by which compensating capacitance is connected in shunt with the range resistance to compensate for the effects of line capacitance. After the auto-ranging and auto-compensation functions are complete, the microprocessor calculates the resistance of the load from the selected range resistance, the excitation signal, and the load voltage signal, and displays of the measured resistance on a digital display of the instrument. 8 figs.

  16. AC Resistance measuring instrument

    DOEpatents

    Hof, Peter J.

    1983-01-01

    An auto-ranging AC resistance measuring instrument for remote measurement of the resistance of an electrical device or circuit connected to the instrument includes a signal generator which generates an AC excitation signal for application to a load, including the device and the transmission line, a monitoring circuit which provides a digitally encoded signal representing the voltage across the load, and a microprocessor which operates under program control to provide an auto-ranging function by which range resistance is connected in circuit with the load to limit the load voltage to an acceptable range for the instrument, and an auto-compensating function by which compensating capacitance is connected in shunt with the range resistance to compensate for the effects of line capacitance. After the auto-ranging and auto-compensation functions are complete, the microprocessor calculates the resistance of the load from the selected range resistance, the excitation signal, and the load voltage signal, and displays of the measured resistance on a digital display of the instrument.

  17. Chitin synthase homologs in three ectomycorrhizal truffles.

    PubMed

    Lanfranco, L; Garnero, L; Delpero, M; Bonfante, P

    1995-12-01

    Degenerate PCR primers were used to amplify a conserved gene portion coding chitin synthase from genomic DNA of six species of ectomycorrhizal truffles. DNA was extracted from both hypogeous fruitbodies and in vitro growing mycelium of Tuber borchii. A single fragment of about 600 bp was amplified for each species. The amplification products from Tuber magnatum, T. borchii and T. ferrugineum were cloned and sequenced, revealing a high degree of identity (91.5%) at the nucleotide level. On the basis of the deduced amino acid sequences these clones were assigned to class II chitin synthase. Southern blot experiments performed on genomic DNA showed that the amplification products derive from a single copy gene. Phylogenetic analysis of the nucleotide sequences of class II chitin synthase genes confirmed the current taxonomic position of the genus Tuber, and suggested a close relationship between T. magnatum and T. uncinatum. PMID:8593947

  18. Functional Characterization of Cucurbitadienol Synthase and Triterpene Glycosyltransferase Involved in Biosynthesis of Mogrosides from Siraitia grosvenorii.

    PubMed

    Dai, Longhai; Liu, Can; Zhu, Yueming; Zhang, Jiangsheng; Men, Yan; Zeng, Yan; Sun, Yuanxia

    2015-06-01

    Mogrosides, the major bioactive components isolated from the fruits of Siraitia grosvenorii, are a family of cucurbitane-type tetracyclic triterpenoid saponins that are used worldwide as high-potency sweeteners and possess a variety of notable pharmacological activities. Mogrosides are synthesized from 2,3-oxidosqualene via a series of reactions catalyzed by cucurbitadienol synthase (CbQ), Cyt P450s (P450s) and UDP glycosyltransferases (UGTs) in vivo. However, the relevant genes have not been characterized to date. In this study, we report successful identification of SgCbQ and UGT74AC1, which were previously predicted via RNA-sequencing (RNA-seq) and digital gene expression (DGE) profile analysis of the fruits of S. grosvenorii. SgCbQ was functionally characterized by expression in the lanosterol synthase-deficient yeast strain GIL77 and was found to accumulate cucurbitadienol as the sole product. UGT74AC1 was heterologously expressed in Escherichia coli as a His-tag protein and it showed specificity for mogrol by transfer of a glucose moiety to the C-3 hydroxyl to form mogroside IE by in vitro enzymatic activity assays. This study reports the identification of CbQ and glycosyltransferase from S. grosvenorii for the first time. The results also suggest that RNA-seq, combined with DGE profile analysis, is a promising approach for discovery of candidate genes involved in biosynthesis of triterpene saponins. PMID:25759326

  19. Homology study of two polyhydroxyalkanoate (PHA) synthases from Pseudomonas aureofaciens.

    PubMed

    Umeda, F; Nishikawa, T; Miyasaka, H; Maeda, I; Kawase, M; Yagi, K

    2001-11-01

    Recently, we have cloned and analyzed two polyhydroxyalkanoate (PHA) synthase genes (phaC1 and phaC2 in the pha cluster) from Pseudomonas aureofaciens. In this report, the deduced amino acid (AA) sequences of PHA synthase 1 and PHA synthase 2 from P. aureofaciens are compared with those from three other bacterial strains (Pseudomonas sp. 61-3, P. oleovorans and P. aeruginosa) containing the homologous pha cluster. The level of homology of either PHA synthase 1 or PHA synthase 2 was high with each enzyme from these three bacterial strains. Furthermore, multialignment of PHA synthase AA sequences implied that both enzymes of PHA synthase 1 and PHA synthase 2 were highly conserved in the four strains including P. aureofaciens. PMID:11916262

  20. Cooling Floor AC Systems

    NASA Astrophysics Data System (ADS)

    Jun, Lu; Hao, Ding; Hong, Zhang; Ce, Gao Dian

    The present HVAC equipments for the residential buildings in the Hot-summer-and-Cold-winter climate region are still at a high energy consuming level. So that the high efficiency HVAC system is an urgently need for achieving the preset government energy saving goal. With its advantage of highly sanitary, highly comfortable and uniform of temperature field, the hot-water resource floor radiation heating system has been widely accepted. This paper has put forward a new way in air-conditioning, which combines the fresh-air supply unit and such floor radiation system for the dehumidification and cooling in summer or heating in winter. By analyze its advantages and limitations, we found that this so called Cooling/ Heating Floor AC System can improve the IAQ of residential building while keep high efficiency quality. We also recommend a methodology for the HVAC system designing, which will ensure the reduction of energy cost of users.

  1. Digital ac monitor

    DOEpatents

    Hart, George W.; Kern, Jr., Edward C.

    1987-06-09

    An apparatus and method is provided for monitoring a plurality of analog ac circuits by sampling the voltage and current waveform in each circuit at predetermined intervals, converting the analog current and voltage samples to digital format, storing the digitized current and voltage samples and using the stored digitized current and voltage samples to calculate a variety of electrical parameters; some of which are derived from the stored samples. The non-derived quantities are repeatedly calculated and stored over many separate cycles then averaged. The derived quantities are then calculated at the end of an averaging period. This produces a more accurate reading, especially when averaging over a period in which the power varies over a wide dynamic range. Frequency is measured by timing three cycles of the voltage waveform using the upward zero crossover point as a starting point for a digital timer.

  2. Thermionic triode generates ac power

    NASA Technical Reports Server (NTRS)

    Kniazzeh, A. G. F.; Scharz, F. C.

    1970-01-01

    Electrostatic grid controls conduction cycle of thermionic diode to convert low dc output voltages to high ac power without undesirable power loss. An ac voltage applied to the grid of this new thermionic triode enables it to convert heat directly into high voltage electrical power.

  3. Automated ac galvanomagnetic measurement system

    NASA Technical Reports Server (NTRS)

    Szofran, F. R.; Espy, P. N.

    1985-01-01

    An automated, ac galvanomagnetic measurement system is described. Hall or van der Pauw measurements in the temperature range 10-300 K can be made at a preselected magnetic field without operator attendance. Procedures to validate sample installation and correct operation of other system functions, such as magnetic field and thermometry, are included. Advantages of ac measurements are discussed.

  4. Improving production of malonyl coenzyme A-derived metabolites by abolishing Snf1-dependent regulation of Acc1.

    PubMed

    Shi, Shuobo; Chen, Yun; Siewers, Verena; Nielsen, Jens

    2014-01-01

    ABSTRACT Acetyl coenzyme A (acetyl-CoA) carboxylase (ACCase) plays a central role in carbon metabolism and has been the site of action for the development of therapeutics or herbicides, as its product, malonyl-CoA, is a precursor for production of fatty acids and other compounds. Control of Acc1 activity in the yeast Saccharomyces cerevisiae occurs mainly at two levels, i.e., regulation of transcription and repression by Snf1 protein kinase at the protein level. Here, we demonstrate a strategy for improving the activity of ACCase in S. cerevisiae by abolishing posttranslational regulation of Acc1 via site-directed mutagenesis. It was found that introduction of two site mutations in Acc1, Ser659 and Ser1157, resulted in an enhanced activity of Acc1 and increased total fatty acid content. As Snf1 regulation of Acc1 is particularly active under glucose-limited conditions, we evaluated the effect of the two site mutations in chemostat cultures. Finally, we showed that our modifications of Acc1 could enhance the supply of malonyl-CoA and therefore successfully increase the production of two industrially important products derived from malonyl-CoA, fatty acid ethyl esters and 3-hydroxypropionic acid. IMPORTANCE ACCase is responsible for carboxylation of acetyl-CoA to produce malonyl-CoA, which is a crucial step in the control of fatty acid metabolism. ACCase opened the door for pharmaceutical treatments of obesity and diabetes as well as the development of new herbicides. ACCase is also recognized as a promising target for developing cell factories, as its malonyl-CoA product serves as a universal precursor for a variety of high-value compounds in white biotechnology. Yeast ACCase is a good model in understanding the enzyme's catalysis, regulation, and inhibition. The present study describes the importance of protein phosphorylation in regulation of yeast ACCase and identifies potential regulation sites. This study led to the generation of a more efficient ACCase, which

  5. Anatomically shaped cranial collimation (ACC) for lateral cephalometric radiography: a technical report.

    PubMed

    Hoogeveen, R C; van der Stelt, P F; Berkhout, W E R

    2014-01-01

    Lateral cephalograms in orthodontic practice display an area cranial of the base of the skull that is not required for diagnostic evaluation. Attempts have been made to reduce the radiation dose to the patient using collimators combining the shielding of the areas above the base of the skull and below the mandible. These so-called "wedge-shaped" collimators have not become standard equipment in orthodontic offices, possibly because these collimators were not designed for today's combination panoramic-cephalometric imaging systems. It also may be that the anatomical variability of the area below the mandible makes this area unsuitable for standardized collimation. In addition, a wedge-shaped collimator shields the cervical vertebrae; therefore, assessment of skeletal maturation, which is based on the stage of development of the cervical vertebrae, cannot be performed. In this report, we describe our investigations into constructing a collimator to be attached to the cephalostat and shield the cranial area of the skull, while allowing the visualization of diagnostically relevant structures and markedly reducing the size of the irradiated area. The shape of the area shielded by this "anatomically shaped cranial collimator" (ACC) was based on mean measurements of cephalometric landmarks of 100 orthodontic patients. It appeared that this collimator reduced the area of irradiation by almost one-third without interfering with the imaging system or affecting the quality of the image. Further research is needed to validate the clinical efficacy of the collimator. PMID:24170799

  6. Identification of novel sesterterpene/triterpene synthase from Bacillus clausii.

    PubMed

    Sato, Tsutomu; Yamaga, Hiroaki; Kashima, Shoji; Murata, Yusuke; Shinada, Tetsuro; Nakano, Chiaki; Hoshino, Tsutomu

    2013-05-10

    Basic enzyme: The tetraprenyl-β-curcumene synthase homologue from the alkalophilic Bacillus clausii catalyses conversions of a geranylfarnesyl diphosphate and a hexaprenyl diphosphate into novel head-to-tail acyclic sesterterpene and triterpene. Tetraprenyl-β-curcumene synthase homologues represent a new family of terpene synthases that form not only sesquarterpene but also sesterterpene and triterpene. PMID:23554321

  7. Overexpression of ACC gene from oleaginous yeast Lipomyces starkeyi enhanced the lipid accumulation in Saccharomyces cerevisiae with increased levels of glycerol 3-phosphate substrates.

    PubMed

    Wang, Jiancai; Xu, Ronghua; Wang, Ruling; Haque, Mohammad Enamul; Liu, Aizhong

    2016-06-01

    The conversion of acetyl-CoA to malonyl-CoA by acetyl-CoA carboxylase (ACC) is the rate-limiting step in fatty acid biosynthesis. In this study, a gene coding for ACC was isolated and characterized from an oleaginous yeast, Lipomyces starkeyi. Real-time quantitative PCR (qPCR) analysis of L. starkeyi acetyl-CoA carboxylase gene (LsACC1) showed that the expression levels were upregulated with the fast accumulation of lipids. The LsACC1 was co-overexpressed with the glycerol 3-phosphate dehydrogenase gene (GPD1), which regulates lipids biosynthesis by supplying another substrates glycerol 3-phosphate for storage lipid assembly, in the non-oleaginous yeast Saccharomyces cerevisiae. Further, the S. cerevisiae acetyl-CoA carboxylase (ScACC1) was transferred with GPD1 and its function was analyzed in comparison with LsACC1. The results showed that overexpressed LsACC1 and GPD1 resulted in a 63% increase in S. cerevisiae. This study gives new data in understanding of the molecular mechanisms underlying the regulation of fatty acids and lipid biosynthesis in yeasts. PMID:26865376

  8. Characterization of a Decapentapletic Gene (AccDpp) from Apis cerana cerana and Its Possible Involvement in Development and Response to Oxidative Stress

    PubMed Central

    Wang, Hongfang; Guo, Xulei; Guo, Xingqi; Sun, Qinghua; Xu, Baohua

    2016-01-01

    To tolerate many acute and chronic oxidative stress-producing agents that exist in the environment, organisms have evolved many classes of signal transduction pathways, including the transforming growth factor β (TGFβ) signal pathway. Decapentapletic gene (Dpp) belongs to the TGFβ superfamily, and studies on Dpp have mainly focused on its role in the regulation of development. No study has investigated the response of Dpp to oxidative pressure in any organism, including Apis cerana cerana (A. cerana cerana). In this study, we identified a Dpp gene from A. cerana cerana named AccDpp. The 5΄ flanking region of AccDpp had many transcription factor binding sites that relevant to development and stress response. AccDpp was expressed at all stages of A. cerana cerana, with its highest expression in 15-day worker bees. The mRNA level of AccDpp was higher in the poison gland and midgut than other tissues. Furthermore, the transcription of AccDpp could be repressed by 4°C and UV, but induced by other treatments, according to our qRT-PCR analysis. It is worth noting that the expression level of AccDpp protein was increased after a certain time when A. cerana cerana was subjected to all simulative oxidative stresses, a finding that was not completely consistent with the result from qRT-PCR. It is interesting that recombinant AccDpp restrained the growth of Escherichia coli, a function that might account for the role of the antimicrobial peptides of AccDpp. In conclusion, these results provide evidence that AccDpp might be implicated in the regulation of development and the response of oxidative pressure. The findings may lay a theoretical foundation for further genetic studies of Dpp. PMID:26881804

  9. Lessons from 455 Fusarium polyketide synthases

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In fungi, polyketide synthases (PKSs) synthesize a structurally diverse array of secondary metabolites (SMs) with a range of biological activities. The most studied SMs are toxic to animals and/or plants, alter plant growth, have beneficial pharmaceutical activities, and/or are brightly colored pigm...

  10. Producing dicarboxylic acids using polyketide synthases

    SciTech Connect

    Katz, Leonard; Fortman, Jeffrey L; Keasling, Jay D

    2013-10-29

    The present invention provides for a polyketide synthase (PKS) capable of synthesizing a dicarboxylic acid (diacid). Such diacids include diketide-diacids and triketide-diacids. The invention includes recombinant nucleic acid encoding the PKS, and host cells comprising the PKS. The invention also includes methods for producing the diacids.

  11. Producing dicarboxylic acids using polyketide synthases

    SciTech Connect

    Katz, Leonard; Fortman, Jeffrey L.; Keasling, Jay D.

    2015-05-26

    The present invention provides for a polyketide synthase (PKS) capable of synthesizing a dicarboxylic acid (diacid). Such diacids include diketide-diacids and triketide-diacids. The invention includes recombinant nucleic acid encoding the PKS, and host cells comprising the PKS. The invention also includes methods for producing the diacids.

  12. Lanosterol Synthase Gene Polymorphisms and Changes in Endogenous Ouabain in the Response to Low Sodium Intake.

    PubMed

    Lanzani, Chiara; Gatti, Guido; Citterio, Lorena; Messaggio, Elisabetta; Delli Carpini, Simona; Simonini, Marco; Casamassima, Nunzia; Zagato, Laura; Brioni, Elena; Hamlyn, John M; Manunta, Paolo

    2016-02-01

    Circulating levels of endogenous ouabain (EO), a vasopressor hormone of adrenocortical origin, are increased by sodium depletion. Furthermore, lanosterol synthase, an enzyme involved in cholesterol biosynthesis, has a missense polymorphism (rs2254524 V642L) that affects EO biosynthesis in adrenocortical cells. Here, we investigated the hypothesis that lanosterol synthase rs2254524 alleles in vivo impact the blood pressure (BP) and EO responses evoked by a low dietary Na intake (<100 mEq/d, 2 weeks) among patients with mild essential hypertension. During the low salt diet, the declines in both systolic BP (SBP: -8.7±1.7 versus -3.0±1.5; P=0.013) and diastolic BP (DBP: -5.1±0.98 versus -1.4±0.94 mm Hg; P<0.05), and the slope of the long-term pressure-natriuresis relationship affected significantly the presence of the lanosterol synthase rs2254524 A variant (AA: 0.71±0.22, AC 0.09±0.13, and CC 0.04±0.11 mEq/mm Hg/24 h; P=0.028). In addition, BP rose in ≈25% of the patients in response to the low salt diet and this was associated with increased circulating EO. Lanosterol synthase gene polymorphisms influence both the salt sensitivity of BP and changes in circulating EO in response to a low salt diet. The response of BP and EO to the low salt diet is markedly heterogeneous. Approximately 25% of patients experienced adverse effects, that is, increased BP and EO when salt intake was reduced and may be at increased long-term risk. The augmented response of EO to the low salt diet further supports the view that adrenocortical function is abnormal in some essential hypertensives. PMID:26667413

  13. BIOGENESIS FACTOR REQUIRED FOR ATP SYNTHASE 3 Facilitates Assembly of the Chloroplast ATP Synthase Complex.

    PubMed

    Zhang, Lin; Duan, Zhikun; Zhang, Jiao; Peng, Lianwei

    2016-06-01

    Thylakoid membrane-localized chloroplast ATP synthases use the proton motive force generated by photosynthetic electron transport to produce ATP from ADP. Although it is well known that the chloroplast ATP synthase is composed of more than 20 proteins with α3β3γ1ε1δ1I1II1III14IV1 stoichiometry, its biogenesis process is currently unclear. To unravel the molecular mechanisms underlying the biogenesis of chloroplast ATP synthase, we performed extensive screening for isolating ATP synthase mutants in Arabidopsis (Arabidopsis thaliana). In the recently identified bfa3 (biogenesis factors required for ATP synthase 3) mutant, the levels of chloroplast ATP synthase subunits were reduced to approximately 25% of wild-type levels. In vivo labeling analysis showed that assembly of the CF1 component of chloroplast ATP synthase was less efficient in bfa3 than in the wild type, indicating that BFA3 is required for CF1 assembly. BFA3 encodes a chloroplast stromal protein that is conserved in higher plants, green algae, and a few species of other eukaryotic algae, and specifically interacts with the CF1β subunit. The BFA3 binding site was mapped to a region in the catalytic site of CF1β. Several residues highly conserved in eukaryotic CF1β are crucial for the BFA3-CF1β interaction, suggesting a coevolutionary relationship between BFA3 and CF1β. BFA3 appears to function as a molecular chaperone that transiently associates with unassembled CF1β at its catalytic site and facilitates subsequent association with CF1α during assembly of the CF1 subcomplex of chloroplast ATP synthase. PMID:27208269

  14. Studies on acetyl-CoA carboxylase and fatty acid synthase from rat mammary gland and mammary tumours.

    PubMed Central

    Ahmad, P M; Feltman, D S; Ahmad, F

    1982-01-01

    The activities of two lipogenic enzymes, acetyl-CoA carboxylase and fatty acid synthase, were determined in two transplantable mammary adenocarcinomas (13762 and R3230AC) carried by non-pregnant, pregnant and lactating rats, and in mammary tissue of control animals (non-tumour-carrying) of comparable physiological states. During mammary-gland differentiation of control or tumour-carrying animals, the activities of acetyl-CoA carboxylase and fatty acid synthase in the lactating gland increased by about 40--50-fold over the values found in non-pregnant animals. On the other hand, in tumours carried by lactating dams there were only modest increases (1.5--2-fold) in acetyl-CoA carboxylase and fatty acid synthase compared with the neoplasms carried by non-pregnant animals. On the basis of the Km values for different substrates and immunodiffusion and immunotitration data, the fatty acid synthase of neoplastic tissues appeared to be indistinguishable from the control mammary-gland enzyme. However, a comparison of the immunotitration and immunodiffusion experiments indicated that the mammary-gland acetyl-CoA carboxylase might differ from the enzyme present in mammary neoplasms. Images Fig. 1. Fig. 2. PMID:6130760

  15. 2016 ESC and ACC/AHA/HFSA heart failure guideline update - what is new and why is it important?

    PubMed

    Jessup, Mariell; Marwick, Thomas H; Ponikowski, Piotr; Voors, Adriaan A; Yancy, Clyde W

    2016-09-14

    Heart failure (HF) is a global epidemic affecting millions of individuals worldwide. Although important progress has been made in the management of HF, this condition remains a common cause of morbidity and death. Since the publication of the previous sets of guidelines for the management of HF, new diagnostic and therapeutic options for HF have emerged. Now, both the ESC and the ACC/AHA/HFSA have simultaneously published an update of their guidelines incorporating, among others, recommendations for the use of new pharmacological therapies for the treatment of HF. For this Viewpoint article, we have asked the chairs of the ESC Task Force, the chairs of the ACC/AHA/HFSA Writing Committee, and an independent opinion leader in the field to offer their expert insight into the new guidelines, highlighting what is new, what the main differences are between the two sets of guidelines, and what steps should be taken to improve the guidelines in future updates. PMID:27625120

  16. Trichinella pseudospiralis vs. T. spiralis thymidylate synthase gene structure and T. pseudospiralis thymidylate synthase retrogene sequence

    PubMed Central

    2014-01-01

    Background Thymidylate synthase is a housekeeping gene, designated ancient due to its role in DNA synthesis and ubiquitous phyletic distribution. The genomic sequences were characterized coding for thymidylate synthase in two species of the genus Trichinella, an encapsulating T. spiralis and a non-encapsulating T. pseudospiralis. Methods Based on the sequence of parasitic nematode Trichinella spiralis thymidylate synthase cDNA, PCR techniques were employed. Results Each of the respective gene structures encompassed 6 exons and 5 introns located in conserved sites. Comparison with the corresponding gene structures of other eukaryotic species revealed lack of common introns that would be shared among selected fungi, nematodes, mammals and plants. The two deduced amino acid sequences were 96% identical. In addition to the thymidylate synthase gene, the intron-less retrocopy, i.e. a processed pseudogene, with sequence identical to the T. spiralis gene coding region, was found to be present within the T. pseudospiralis genome. This pseudogene, instead of the gene, was confirmed by RT-PCR to be expressed in the parasite muscle larvae. Conclusions Intron load, as well as distribution of exon and intron phases in thymidylate synthase genes from various sources, point against the theory of gene assembly by the primordial exon shuffling and support the theory of evolutionary late intron insertion into spliceosomal genes. Thymidylate synthase pseudogene expressed in T. pseudospiralis muscle larvae is designated a retrogene. PMID:24716800

  17. A comparison of native GPU computing versus OpenACC for implementing flow-routing algorithms in hydrological applications

    NASA Astrophysics Data System (ADS)

    Rueda, Antonio J.; Noguera, José M.; Luque, Adrián

    2016-02-01

    In recent years GPU computing has gained wide acceptance as a simple low-cost solution for speeding up computationally expensive processing in many scientific and engineering applications. However, in most cases accelerating a traditional CPU implementation for a GPU is a non-trivial task that requires a thorough refactorization of the code and specific optimizations that depend on the architecture of the device. OpenACC is a promising technology that aims at reducing the effort required to accelerate C/C++/Fortran code on an attached multicore device. Virtually with this technology the CPU code only has to be augmented with a few compiler directives to identify the areas to be accelerated and the way in which data has to be moved between the CPU and GPU. Its potential benefits are multiple: better code readability, less development time, lower risk of errors and less dependency on the underlying architecture and future evolution of the GPU technology. Our aim with this work is to evaluate the pros and cons of using OpenACC against native GPU implementations in computationally expensive hydrological applications, using the classic D8 algorithm of O'Callaghan and Mark for river network extraction as case-study. We implemented the flow accumulation step of this algorithm in CPU, using OpenACC and two different CUDA versions, comparing the length and complexity of the code and its performance with different datasets. We advance that although OpenACC can not match the performance of a CUDA optimized implementation (×3.5 slower in average), it provides a significant performance improvement against a CPU implementation (×2-6) with by far a simpler code and less implementation effort.

  18. Operation Method for AC Motor Control during Power Interruption in Direct AC/AC Converter System

    NASA Astrophysics Data System (ADS)

    Shizu, Keiichiro; Azuma, Satoshi

    Direct AC/AC converters have been studied due to their potential use in power converters with no DC-link capacitor, which can contribute to the miniaturization of power converters. However, the absence of a DC-link capacitor makes it difficult to control the AC motor during power interruption. First, this paper proposes a system that realizes AC motor control during power interruption by utilizing a clamp capacitor. In general, direct AC/AC converters have a clamp circuit consisting of a rectifier diode(s) and a clamp capacitor in order to avoid over-voltages. In the proposed system, there is an additional semiconductor switch reverse-parallel to the rectifier diode(s), and the clamp capacitor voltage can be utilized for AC motor control by turning on the additional switch. Second, this paper discusses an operation method for AC motor control and clamp capacitor voltage control during power interruption. In the proposed method “DC-link voltage control”, the kinetic energy in the AC motor is transformed into electrical energy and stored in the clamp capacitor; the clamp capacitor is therefore charged and the capacitor voltage is controlled to remain constant at an instruction value. Third, this paper discusses a switching operation during power interruption. A dead-time is introduced between the operation of turning off all switches on the rectifier side and the operation of turning on the additional switch, which prevents the occurrence of a short circuit between the interrupted power source and the clamp capacitor. Finally, experimental results are presented. During power interruptions, an output current was continuously obtained and the clamp capacitor voltage was maintained to be equal to the instruction value of the capacitor voltage. These results indicate that both AC motor control and capacitor voltage control were successfully achieved by using the proposed system.

  19. Role of cystathionine beta synthase in lipid metabolism in ovarian cancer

    PubMed Central

    Chakraborty, Prabir K.; Xiong, Xunhao; Mustafi, Soumyajit Banerjee; Saha, Sounik; Dhanasekaran, Danny; Mandal, Nawajes A.; McMeekin, Scott; Bhattacharya, Resham; Mukherjee, Priyabrata

    2015-01-01

    Elevated lipid metabolism is implicated in poor survival in ovarian cancer (OC) and other cancers; however, current lipogenesis-targeting strategies lack cancer cell specificity. Here, we identify a novel role of cystathionine beta-synthase (CBS), a sulphur amino acid metabolizing enzyme highly expressed in several ovarian cancer cell lines, in driving deregulated lipid metabolism in OC. We examined the role of CBS in regulation of triglycerides, cholesterol and lipogenic enzymes via the lipogenic transcription factors SREBP1 and SREBP2. CBS silencing attenuated the expression of number of key enzymes involved in lipid synthesis (FASN and ACC1). Additionally CBS abrogates lipid uptake in OC cells. Gene silencing of CBS or SREBPs abrogated cellular migration and invasion in OC, while ectopic expression of SREBPs can rescue phenotypic effects of CBS silencing by restoring cell migration and invasion. Mechanistically, CBS represses SREBP1 and SREBP2 at the transcription levels by modulating the transcription factor Sp1. We further established the roles of both CBS and SREBPs in regulating ovarian tumor growth in vivo. In orthotopic tumor models, CBS or SREBP silencing resulted in reduced tumor cells proliferation, blood vessels formation and lipid content. Hence, cancer-selective disruption of the lipid metabolism pathway is possible by targeting CBS and, at least for OC, promises a profound benefit. PMID:26452259

  20. Reduced AMPK-ACC and mTOR signaling in muscle from older men, and effect of resistance exercise.

    PubMed

    Li, Mengyao; Verdijk, Lex B; Sakamoto, Kei; Ely, Brian; van Loon, Luc J C; Musi, Nicolas

    2012-01-01

    AMP-activated protein kinase (AMPK) is a key energy-sensitive enzyme that controls numerous metabolic and cellular processes. Mammalian target of rapamycin (mTOR) is another energy/nutrient-sensitive kinase that controls protein synthesis and cell growth. In this study we determined whether older versus younger men have alterations in the AMPK and mTOR pathways in skeletal muscle, and examined the effect of a long term resistance type exercise training program on these signaling intermediaries. Older men had decreased AMPKα2 activity and lower phosphorylation of AMPK and its downstream signaling substrate acetyl-CoA carboxylase (ACC). mTOR phosphylation also was reduced in muscle from older men. Exercise training increased AMPKα1 activity in older men, however, AMPKα2 activity, and the phosphorylation of AMPK, ACC and mTOR, were not affected. In conclusion, older men have alterations in the AMPK-ACC and mTOR pathways in muscle. In addition, prolonged resistance type exercise training induces an isoform-selective up regulation of AMPK activity. PMID:23000302

  1. AC photovoltaic module magnetic fields

    SciTech Connect

    Jennings, C.; Chang, G.J.; Reyes, A.B.; Whitaker, C.M.

    1997-12-31

    Implementation of alternating current (AC) photovoltaic (PV) modules, particularly for distributed applications such as PV rooftops and facades, may be slowed by public concern about electric and magnetic fields (EMF). This paper documents magnetic field measurements on an AC PV module, complementing EMF research on direct-current PV modules conducted by PG and E in 1993. Although not comprehensive, the PV EMF data indicate that 60 Hz magnetic fields (the EMF type of greatest public concern) from PV modules are comparable to, or significantly less than, those from household appliances. Given the present EMF research knowledge, AC PV module EMF may not merit considerable concern.

  2. Geranyl diphosphate synthase large subunit, and methods of use

    DOEpatents

    Croteau, Rodney B.; Burke, Charles C.; Wildung, Mark R.

    2001-10-16

    A cDNA encoding geranyl diphosphate synthase large subunit from peppermint has been isolated and sequenced, and the corresponding amino acid sequence has been determined. Replicable recombinant cloning vehicles are provided which code for geranyl diphosphate synthase large subunit). In another aspect, modified host cells are provided that have been transformed, transfected, infected and/or injected with a recombinant cloning vehicle and/or DNA sequence encoding geranyl diphosphate synthase large subunit. In yet another aspect, the present invention provides isolated, recombinant geranyl diphosphate synthase protein comprising an isolated, recombinant geranyl diphosphate synthase large subunit protein and an isolated, recombinant geranyl diphosphate synthase small subunit protein. Thus, systems and methods are provided for the recombinant expression of geranyl diphosphate synthase.

  3. Circumpolar Estimates of Isopycnal Mixing in the ACC from Argo Floats

    NASA Astrophysics Data System (ADS)

    Roach, C. J.; Balwada, D.; Speer, K. G.

    2015-12-01

    There are few direct observations of cross-stream isopycnal mixing in the interior of the Southern Ocean, yet such measurements are needed to determine the role of eddies transporting properties across the ACC, and key to progress toward testing theories of meridional overturning. In light of this we examine if it is possible to obtain estimates of mixing from Argo float trajectories. We divided the Southern Ocean into overlapping 15ο longitude bins before estimating mixing. Resulting diffusivities ranged from 300 to 3000 m2s-1, with peaks corresponding to the Scotia Sea; Kerguelen and Campbell Plateaus. Comparison of our diffusivities with previous regional studies demonstrated good agreement. Tests of the methodology in the DIMES region found that mixing from Argo floats agreed closely with mixing from RAFOS floats. To further test the method we used the Southern Ocean State Estimate velocity fields to advect particles with Argo and RAFOS float like behaviours. Stirring estimates from the particles agreed well with each other in the Kerguelen Island region, South Pacific and Scotia Sea, despite the differences in the imposed behaviour. Finally, these estimates were compared to mixing length suppression theory presented in Ferrari and Nikurashin 2010. This mixing length suppression theory quantifies horizontal diffusivity similar to Prandtl (1925), but the mixing length is suppressed in the presence of mean flows and eddy phase speeds. Our results suggest that the theory can explain both the structure and magnitude of mixing using mean flow data. An exception is near the Kerguelen and Campbell Plateaus where theory under-estimates mixing relative to our results.

  4. Characterization of genes in the cellulose-synthesizing operon (acs operon) of Acetobacter xylinum: implications for cellulose crystallization.

    PubMed Central

    Saxena, I M; Kudlicka, K; Okuda, K; Brown, R M

    1994-01-01

    The synthesis of an extracellular ribbon of cellulose in the bacterium Acetobacter xylinum takes place from linearly arranged, membrane-localized, cellulose-synthesizing and extrusion complexes that direct the coupled steps of polymerization and crystallization. To identify the different components involved in this process, we isolated an Acetobacter cellulose-synthesizing (acs) operon from this bacterium. Analysis of DNA sequence shows the presence of three genes in the acs operon, in which the first gene (acsAB) codes for a polypeptide with a molecular mass of 168 kDa, which was identified as the cellulose synthase. A single base change in the previously reported DNA sequence of this gene, resulting in a frameshift and synthesis of a larger protein, is described in the present paper, along with the sequences of the other two genes (acsC and acsD). The requirement of the acs operon genes for cellulose production was determined using site-determined TnphoA/Kanr GenBlock insertion mutants. Mutant analysis showed that while the acsAB and acsC genes were essential for cellulose production in vivo, the acsD mutant produced reduced amounts of two cellulose allomorphs (cellulose I and cellulose II), suggesting that the acsD gene is involved in cellulose crystallization. The role of the acs operon genes in determining the linear array of intramembranous particles, which are believed to be sites of cellulose synthesis, was investigated for the different mutants; however, this arrangement was observed only in cells that actively produced cellulose microfibrils, suggesting that it may be influenced by the crystallization of the nascent glucan chains. Images PMID:8083166

  5. Direct observations of the ACC transport across the Kerguelen Plateau from the 2009-2010 TRACK cruises

    NASA Astrophysics Data System (ADS)

    Hyang Park, Young; Vivier, Frédéric; Roquet, Fabien; Kestenare, Elodie; Sekma, Hela; Durand, Isabelle

    2010-05-01

    The Kerguelen Plateau is considered as a major barrier to the eastward flowing Antarctic Circumpolar Current (ACC), diverting about 2/3 of its transport to the north of the plateau and the remaining transport across the vast plateau developed between the Kerguelen Islands and Antarctica. However, due to the lack of systematic high-quality observations especially across the Fawn Trough, our knowledge of ACC branches and associated transports across the Kerguelen Plateau has been largely indirect and debated, with previous transport estimates ranging from 30 to 100 Sv. In order to fill this knowledge gap, we undertook full-depth CTD and LADCP measurements in the Fawn Trough area and moored three lines of a total of 9 current-meters across the Fawn Trough in February-March 2009 during the TRACK-1 cruise. The TRACK-1 data have permitted us to document for the first time a detailed vertical current structure especially across the Fawn Trough as well as the Deep Western Boundary Current (DWBC) on the eastern flank of the Kerguelen Plateau at 58°S. The Fawn Trough Current appears as a principal across-plateau jet associated with the Southern ACC Front, concentrating the majority (43 Sv) of the eastward transport passing to the south of the Kerguelen Islands (58 Sv), compared to ~92 Sv at the Subantarctic Front as estimated previously to the north of the islands. This yields a total transport of ~150 Sv for the ACC transiting through the Kerguelen longitude, consistent with other independent estimates in the other sectors of the Southern Ocean, but with an up-to-date partition of ~60% of the transport passing to the north of the Kerguelen Plateau and ~40% across the plateau. The DWBC transport at 58°S is estimated as 43 Sv, of which 36 Sv come from the northward turning of the westward flowing Antarctic Slope Current and the rest (7 Sv) originates from the southernmost branch of the ACC passing through the northern Princess Elizabeth Trough. Two other transport branches

  6. The cellulose synthase companion proteins act non-redundantly with CELLULOSE SYNTHASE INTERACTING1/POM2 and CELLULOSE SYNTHASE 6

    PubMed Central

    Endler, Anne; Schneider, Rene; Kesten, Christopher; Lampugnani, Edwin R.; Persson, Staffan

    2016-01-01

    ABSTRACT Cellulose is a cell wall constituent that is essential for plant growth and development, and an important raw material for a range of industrial applications. Cellulose is synthesized at the plasma membrane by massive cellulose synthase (CesA) complexes that track along cortical microtubules in elongating cells of Arabidopsis through the activity of the protein CELLULOSE SYNTHASE INTERACTING1 (CSI1). In a recent study we identified another family of proteins that also are associated with the CesA complex and microtubules, and that we named COMPANIONS OF CELLULOSE SYNTHASE (CC). The CC proteins protect the cellulose synthesising capacity of Arabidopsis seedlings during exposure to adverse environmental conditions by enhancing microtubule dynamics. In this paper we provide cell biology and genetic evidence that the CSI1 and the CC proteins fulfil distinct functions during cellulose synthesis. We also show that the CC proteins are necessary to aid cellulose synthesis when components of the CesA complex are impaired. These data indicate that the CC proteins have a broad role in aiding cellulose synthesis during environmental changes and when core complex components are non-functional. PMID:26829351

  7. Ac traction gets on track

    SciTech Connect

    O`Connor, L.

    1995-09-01

    This article describes inverter-based ac traction systems which give freight locomotives greater adhesion, pulling power, and braking capacity. In the 1940s, dc traction replaced the steam engine as a source of train propulsion, and it has ruled the freight transportation industry ever since. But now, high-performance ac-traction systems, with their unprecedented levels of pulling power and adhesion, are becoming increasingly common on America`s freight railroads. In thousands of miles of demonstration tests, today`s ac-traction systems have outperformed traditional dc-motor driven systems. Major railroad companies are convinced enough of the benefits of ac traction to have integrated it into their freight locomotives.

  8. Cardiac-specific deletion of acetyl CoA carboxylase 2 (ACC2) prevents metabolic remodeling during pressure-overload hypertrophy

    PubMed Central

    Kolwicz, Stephen C.; Olson, David P.; Marney, Luke C.; Garcia-Menendez, Lorena; Synovec, Robert E.; Tian, Rong

    2012-01-01

    Rationale Decreased fatty acid oxidation (FAO) with increased reliance on glucose are hallmarks of metabolic remodeling that occurs in pathological cardiac hypertrophy and is associated with decreased myocardial energetics and impaired cardiac function. To date, it has not been tested whether prevention of the metabolic switch that occurs during the development of cardiac hypertrophy has unequivocal benefits on cardiac function and energetics. Objectives Since malonyl CoA production via acetyl CoA carboxylase 2 (ACC2) inhibits mitochondrial fatty acid transport, we hypothesized that mice with a cardiac-specific deletion of ACC2 (ACC2H−/−) would maintain cardiac fatty acid oxidation (FAO) and improve function and energetics during the development of pressure-overload hypertrophy. Methods and Results ACC2 deletion led to a significant reduction in cardiac malonyl CoA levels. In isolated perfused heart experiments, left ventricular (LV) function and oxygen consumption were similiar in ACC2H−/− mice despite an ~60% increase in FAO compared to controls (CON). After 8 weeks of pressure-overload via transverse aortic constriction (TAC), ACC2H−/− mice exhibited a substrate utilization profile similar to sham animals while CON-TAC hearts had decreased FAO with increased glycolysis and anaplerosis. Myocardial energetics, assessed by 31P NMR spectroscopy, and cardiac function were maintained in ACC2H−/− after 8 weeks of TAC. Furthermore, ACC2H−/−-TAC demonstrated an attenuation of cardiac hypertrophy with a significant reduction in fibrosis relative to CON-TAC. Conclusions These data suggest that reversion to the fetal metabolic profile in chronic pathological hypertrophy is associated with impaired myocardial function and energetics and maintenance of the inherent cardiac metabolic profile and mitochondrial oxidative capacity is a viable therapeutic strategy. PMID:22730442

  9. Structural Evidence for Direct Interactions Between the BRCT Domains of Human BRCA1 and a Phospho-Peptide from Human ACC1

    SciTech Connect

    Shen,Y.; Tong, L.

    2008-01-01

    The tandem BRCA1 C-terminal (BRCT) domains are phospho-serine/threonine recognition modules essential for the function of BRCA1. Recent studies suggest that acetyl-CoA carboxylase 1 (ACC1), an enzyme with crucial roles in de novo fatty acid biosynthesis and lipogenesis and essential for cancer cell survival, may be a novel binding partner for BRCA1, through interactions with its BRCT domains. We report here the crystal structure at 3.2 Angstroms resolution of human BRCA1 BRCT domains in complex with a phospho-peptide from human ACC1 (p-ACC1 peptide, with the sequence 1258-DSPPQ-pS-PTFPEAGH-1271), which provides molecular evidence for direct interactions between BRCA1 and ACC1. The p-ACC1 peptide is bound in an extended conformation, located in a groove between the tandem BRCT domains. There are recognizable and significant structural differences to the binding modes of two other phospho-peptides to these domains, from BACH1 and CtIP, even though they share a conserved pSer-Pro-(Thr/Val)-Phe motif. Our studies establish a framework for understanding the regulation of lipid biosynthesis by BRCA1 through its inhibition of ACC1 activity, which could be a novel tumor suppressor function of BRCA1.

  10. Cloning, expression patterns, and preliminary characterization of AccCPR24, a novel RR-1 type cuticle protein gene from Apis cerana cerana.

    PubMed

    Chu, Xiaoqian; Lu, Wenjing; Zhang, Yuanying; Guo, Xingqi; Sun, Rujiang; Xu, Baohua

    2013-11-01

    Cuticular proteins (CPs) are key components of insect cuticle, a structure that plays a pivotal role in insect development and defense. In this study, we cloned the full-length cDNA of a CP gene from Apis cerana cerana (AccCPR24). An amino acid sequence alignment indicated that AccCPR24 contains the conserved Rebers and Riddiford consensus sequence and shares high similarity with the genes from other hymenopteran insects. We then isolated the genomic DNA and found that the first intron, which is present in other CP genes, is absent in AccCPR24. Real-time quantitative polymerase chain reaction (qPCR) analysis revealed that AccCPR24 is highly expressed in the late pupal stage and midgut. Expression was inhibited by an exogenous ecdysteroid in vitro but was enhanced by this hormone in vivo; environmental stressors, such as heavy metals and pesticides, also influenced gene expression. In addition, a disc diffusion assay showed that AccCPR24 enhanced the ability of bacterial cells to resist multiple stresses. We infer from our results that AccCPR24 acts in honeybee development and in protecting these insects from abiotic stresses. PMID:24115354

  11. A novel 1-Cys thioredoxin peroxidase gene in Apis cerana cerana: characterization of AccTpx4 and its role in oxidative stresses.

    PubMed

    Huaxia, Yifeng; Wang, Fang; Yan, Yan; Liu, Feng; Wang, Hongfang; Guo, Xingqi; Xu, Baohua

    2015-07-01

    Thioredoxin peroxidase (Tpx), also named peroxiredoxin (Prx), is an important peroxidase that can protect organisms against stressful environments. AccTpx4, a 1-Cys thioredoxin peroxidase gene from the Chinese honey bee Apis cerana cerana, was cloned and characterized. The AccTpx4 gene encodes a protein that is predicted to contain the conserved PVCTTE motif from 1-Cys peroxiredoxin. Quantitative real-time PCR (Q-PCR) and Western blotting revealed that AccTpx4 was induced by various oxidative stresses, such as cold, heat, insecticides, H(2)O(2), and HgCl(2). The in vivo peroxidase activity assay showed that recombinant AccTpx4 protein could efficiently degrade H(2)O(2) in the presence of DL-dithiothreitol (DTT). In addition, disc fusion assays revealed that AccTpx4 could function to protect cells against oxidative stresses. These results indicate that AccTpx4 plays an important role in oxidative stress responses and may contribute to the conservation of honeybees. PMID:25971604

  12. (R)-citramalate synthase in methanogenic archaea.

    PubMed

    Howell, D M; Xu, H; White, R H

    1999-01-01

    The Methanococcus jannaschii gene MJ1392 was cloned, and its protein product was hyperexpressed in Escherichia coli. The resulting protein was purified and shown to catalyze the condensation of pyruvate and acetyl coenzyme A, with the formation of (R)-citramalate. Thus, this gene (cimA) encodes an (R)-citramalate synthase (CimA). This is the first identification of this enzyme, which is likely involved in the biosynthesis of isoleucine. PMID:9864346

  13. Chrysanthemyl Diphosphate Synthase Operates in Planta as a Bifunctional Enzyme with Chrysanthemol Synthase Activity*

    PubMed Central

    Yang, Ting; Gao, Liping; Hu, Hao; Stoopen, Geert; Wang, Caiyun; Jongsma, Maarten A.

    2014-01-01

    Chrysanthemyl diphosphate synthase (CDS) is the first pathway-specific enzyme in the biosynthesis of pyrethrins, the most widely used plant-derived pesticide. CDS catalyzes c1′-2-3 cyclopropanation reactions of two molecules of dimethylallyl diphosphate (DMAPP) to yield chrysanthemyl diphosphate (CPP). Three proteins are known to catalyze this cyclopropanation reaction of terpene precursors. Two of them, phytoene and squalene synthase, are bifunctional enzymes with both prenyltransferase and terpene synthase activity. CDS, the other member, has been reported to perform only the prenyltransferase step. Here we show that the NDXXD catalytic motif of CDS, under the lower substrate conditions prevalent in plants, also catalyzes the next step, converting CPP into chrysanthemol by hydrolyzing the diphosphate moiety. The enzymatic hydrolysis reaction followed conventional Michaelis-Menten kinetics, with a Km value for CPP of 196 μm. For the chrysanthemol synthase activity, DMAPP competed with CPP as substrate. The DMAPP concentration required for half-maximal activity to produce chrysanthemol was ∼100 μm, and significant substrate inhibition was observed at elevated DMAPP concentrations. The N-terminal peptide of CDS was identified as a plastid-targeting peptide. Transgenic tobacco plants overexpressing CDS emitted chrysanthemol at a rate of 0.12–0.16 μg h−1 g−1 fresh weight. We propose that CDS should be renamed a chrysanthemol synthase utilizing DMAPP as substrate. PMID:25378387

  14. Chrysanthemyl diphosphate synthase operates in planta as a bifunctional enzyme with chrysanthemol synthase activity.

    PubMed

    Yang, Ting; Gao, Liping; Hu, Hao; Stoopen, Geert; Wang, Caiyun; Jongsma, Maarten A

    2014-12-26

    Chrysanthemyl diphosphate synthase (CDS) is the first pathway-specific enzyme in the biosynthesis of pyrethrins, the most widely used plant-derived pesticide. CDS catalyzes c1'-2-3 cyclopropanation reactions of two molecules of dimethylallyl diphosphate (DMAPP) to yield chrysanthemyl diphosphate (CPP). Three proteins are known to catalyze this cyclopropanation reaction of terpene precursors. Two of them, phytoene and squalene synthase, are bifunctional enzymes with both prenyltransferase and terpene synthase activity. CDS, the other member, has been reported to perform only the prenyltransferase step. Here we show that the NDXXD catalytic motif of CDS, under the lower substrate conditions prevalent in plants, also catalyzes the next step, converting CPP into chrysanthemol by hydrolyzing the diphosphate moiety. The enzymatic hydrolysis reaction followed conventional Michaelis-Menten kinetics, with a Km value for CPP of 196 μm. For the chrysanthemol synthase activity, DMAPP competed with CPP as substrate. The DMAPP concentration required for half-maximal activity to produce chrysanthemol was ∼100 μm, and significant substrate inhibition was observed at elevated DMAPP concentrations. The N-terminal peptide of CDS was identified as a plastid-targeting peptide. Transgenic tobacco plants overexpressing CDS emitted chrysanthemol at a rate of 0.12-0.16 μg h(-1) g(-1) fresh weight. We propose that CDS should be renamed a chrysanthemol synthase utilizing DMAPP as substrate. PMID:25378387

  15. CTP synthase forms cytoophidia in the cytoplasm and nucleus

    SciTech Connect

    Gou, Ke-Mian; Chang, Chia-Chun; Shen, Qing-Ji; Sung, Li-Ying; Liu, Ji-Long

    2014-04-15

    CTP synthase is an essential metabolic enzyme responsible for the de novo synthesis of CTP. Multiple studies have recently showed that CTP synthase protein molecules form filamentous structures termed cytoophidia or CTP synthase filaments in the cytoplasm of eukaryotic cells, as well as in bacteria. Here we report that CTP synthase can form cytoophidia not only in the cytoplasm, but also in the nucleus of eukaryotic cells. Both glutamine deprivation and glutamine analog treatment promote formation of cytoplasmic cytoophidia (C-cytoophidia) and nuclear cytoophidia (N-cytoophidia). N-cytoophidia are generally shorter and thinner than their cytoplasmic counterparts. In mammalian cells, both CTP synthase 1 and CTP synthase 2 can form cytoophidia. Using live imaging, we have observed that both C-cytoophidia and N-cytoophidia undergo multiple rounds of fusion upon glutamine analog treatment. Our study reveals the coexistence of cytoophidia in the cytoplasm and nucleus, therefore providing a good opportunity to investigate the intracellular compartmentation of CTP synthase. - Highlights: • CTP synthase forms cytoophidia not only in the cytoplasm but also in the nucleus. • Glutamine deprivation and Glutamine analogs promotes cytoophidium formation. • N-cytoophidia exhibit distinct morphology when compared to C-cytoophidia. • Both CTP synthase 1 and CTP synthase 2 form cytoophidia in mammalian cells. • Fusions of cytoophidia occur in the cytoplasm and nucleus.

  16. Oligosaccharide Binding in Escherichia coli Glycogen Synthase

    SciTech Connect

    Sheng, Fang; Yep, Alejandra; Feng, Lei; Preiss, Jack; Geiger, James H.

    2010-11-17

    Glycogen/starch synthase elongates glucan chains and is the key enzyme in the synthesis of glycogen in bacteria and starch in plants. Cocrystallization of Escherichia coli wild-type glycogen synthase (GS) with substrate ADPGlc and the glucan acceptor mimic HEPPSO produced a closed form of GS and suggests that domain-domain closure accompanies glycogen synthesis. Cocrystallization of the inactive GS mutant E377A with substrate ADPGlc and oligosaccharide results in the first oligosaccharide-bound glycogen synthase structure. Four bound oligosaccharides are observed, one in the interdomain cleft (G6a) and three on the N-terminal domain surface (G6b, G6c, and G6d). Extending from the center of the enzyme to the interdomain cleft opening, G6a mostly interacts with the highly conserved N-terminal domain residues lining the cleft of GS. The surface-bound oligosaccharides G6c and G6d have less interaction with enzyme and exhibit a more curled, helixlike structural arrangement. The observation that oligosaccharides bind only to the N-terminal domain of GS suggests that glycogen in vivo probably binds to only one side of the enzyme to ensure unencumbered interdomain movement, which is required for efficient, continuous glucan-chain synthesis.

  17. Thermostable malate synthase of Streptomyces thermovulgaris.

    PubMed

    Goh, L L; Koh, R; Loke, P; Sim, T S

    2003-10-01

    The gene, encoding malate synthase (MS), aceB, was cloned from the thermophilic bacterium Streptomyces thermovulgaris by homology-based PCR. The 1,626-bp cloned fragment encodes a protein consisting of 541 amino acids. S. thermovulgaris malate synthase (stMS) gene was over-expressed in Escherichia coli using a glutathione-S transferase (GST) fusion vector (pGEX-6P-1), purified by affinity chromatography, and subsequently cleaved from its GST fusion partner. The purified stMS was characterized and compared to a mesophilic malate synthase (scMS) from Streptomyces coelicolor. stMS exhibited higher temperature optima (40-60 degrees C) than those of scMS (28-37 degrees C). It was more thermostable and very resistant to the chemical denaturant urea. Amino acid sequence comparison of stMS with four mesophilic streptomycete MSs indicated that they share 70.9-91.4% amino acid identities, with stMS possessing slightly more charged residues (approximately 31%) than its mesophilic counterparts (approximately 28-29%). Seven charged residues (E85, R187, R209, H239, H364, R382 and K520) that were unique to stMS may be selectively and strategically placed to support its peculiar characteristics. PMID:13680388

  18. Structure of a modular polyketide synthase

    PubMed Central

    Dutta, Somnath; Whicher, Jonathan R.; Hansen, Douglas A.; Hale, Wendi A.; Chemler, Joseph A.; Congdon, Grady R.; Narayan, Alison R.; Håkansson, Kristina; Sherman, David H.; Smith, Janet L.

    2014-01-01

    Polyketide natural products constitute a broad class of compounds with diverse structural features and biological activities. Their biosynthetic machinery, represented by type I polyketide synthases, has an architecture in which successive modules catalyze two-carbon linear extensions and keto group processing reactions on intermediates covalently tethered to carrier domains. We employed electron cryo-microscopy to visualize a full-length module and determine sub-nanometer resolution 3D reconstructions that revealed an unexpectedly different architecture compared to the homologous dimeric mammalian fatty acid synthase. A single reaction chamber provides access to all catalytic sites for the intra-module carrier domain. In contrast, the carrier from the preceding module uses a separate entrance outside the reaction chamber to deliver the upstream polyketide intermediate for subsequent extension and modification. This study reveals for the first time the structural basis for both intra-module and inter-module substrate transfer in polyketide synthases, and establishes a new model for molecular dissection of these multifunctional enzyme systems. PMID:24965652

  19. Genomic organization of plant terpene synthases and molecular evolutionary implications.

    PubMed Central

    Trapp, S C; Croteau, R B

    2001-01-01

    Terpenoids are the largest, most diverse class of plant natural products and they play numerous functional roles in primary metabolism and in ecological interactions. The first committed step in the formation of the various terpenoid classes is the transformation of the prenyl diphosphate precursors, geranyl diphosphate, farnesyl diphosphate, and geranylgeranyl diphosphate, to the parent structures of each type catalyzed by the respective monoterpene (C(10)), sesquiterpene (C(15)), and diterpene synthases (C(20)). Over 30 cDNAs encoding plant terpenoid synthases involved in primary and secondary metabolism have been cloned and characterized. Here we describe the isolation and analysis of six genomic clones encoding terpene synthases of conifers, [(-)-pinene (C(10)), (-)-limonene (C(10)), (E)-alpha-bisabolene (C(15)), delta-selinene (C(15)), and abietadiene synthase (C(20)) from Abies grandis and taxadiene synthase (C(20)) from Taxus brevifolia], all of which are involved in natural products biosynthesis. Genome organization (intron number, size, placement and phase, and exon size) of these gymnosperm terpene synthases was compared to eight previously characterized angiosperm terpene synthase genes and to six putative terpene synthase genomic sequences from Arabidopsis thaliana. Three distinct classes of terpene synthase genes were discerned, from which assumed patterns of sequential intron loss and the loss of an unusual internal sequence element suggest that the ancestral terpenoid synthase gene resembled a contemporary conifer diterpene synthase gene in containing at least 12 introns and 13 exons of conserved size. A model presented for the evolutionary history of plant terpene synthases suggests that this superfamily of genes responsible for natural products biosynthesis derived from terpene synthase genes involved in primary metabolism by duplication and divergence in structural and functional specialization. This novel molecular evolutionary approach focused

  20. Austrian Carbon Calculator (ACC) - modelling soil carbon dynamics in Austrian soils

    NASA Astrophysics Data System (ADS)

    Sedy, Katrin; Freudenschuss, Alexandra; Zethner, Gehard; Spiegel, Heide; Franko, Uwe; Gründling, Ralf; Xaver Hölzl, Franz; Preinstorfer, Claudia; Haslmayr, Hans Peter; Formayer, Herbert

    2014-05-01

    Austrian Carbon Calculator (ACC) - modelling soil carbon dynamics in Austrian soils. The project funded by the Klima- und Energiefonds, Austrian Climate Research Programme, 4th call Authors: Katrin Sedy, Alexandra Freudenschuss, Gerhard Zethner (Environment Agency Austria), Heide Spiegel (Austrian Agency for Health and Food Safety), Uwe Franko, Ralf Gründling (Helmholtz Centre for Environmental Research) Climate change will affect plant productivity due to weather extremes. However, adverse effects could be diminished and satisfying production levels may be maintained with proper soil conditions. To sustain and optimize the potential of agricultural land for plant productivity it will be necessary to focus on preserving and increasing soil organic carbon (SOC). Carbon sequestration in agricultural soils is strongly influenced by management practice. The present management is affected by management practices that tend to speed up carbon loss. Crop rotation, soil cultivation and the management of crop residues are very important measures to influence carbon dynamics and soil fertility. For the future it will be crucial to focus on practical measures to optimize SOC and to improve soil structure. To predict SOC turnover the existing humus balance model the application of the "Carbon Candy Balance" was verified by results from Austrian long term field experiments and field data of selected farms. Thus the main aim of the project is to generate a carbon balancing tool box that can be applied in different agricultural production regions to assess humus dynamics due to agricultural management practices. The toolbox will allow the selection of specific regional input parameters for calculating the C-balance at field level. However farmers or other interested user can also apply their own field data to receive the result of C-dynamics under certain management practises within the next 100 years. At regional level the impact of predefined changes in agricultural management

  1. Identification and characterization of the polyketide synthase involved in ochratoxin A biosynthesis in Aspergillus carbonarius

    SciTech Connect

    Gallo, Antonia; Knox, Benjamin P.; Bruno, Kenneth S.; Solfrizzo, Michele; Baker, Scott E.; Perrone, Giancarlo

    2014-06-02

    Ochratoxin A (OTA) is a potent mycotoxin produced by Aspergillus and Penicillium species and is a common contaminant of a wide variety of food commodities, with Aspergillus carbonarius being the main producer of OTA contamination in grapes and wine. The molecular structure of OTA is composed of a dihydroisocoumarin ring linked to phenylalanine and, as shown in different producing fungal species, a polyketide synthase (PKS) is a component of the OTA biosynthetic pathway. Similar to observations in other filamentous ascomycetes, the genome sequence of A. carbonarius contains a large number of genes predicted to encode PKSs. In this work a pks gene identified within the putative OTA cluster of A. carbonarius, designated as AcOTApks, was inactivated and the resulting mutant strain was unable to produce OTA, confirming the role of AcOTApks in this biosynthetic pathway. AcOTApks protein is characteristic of the highly reduced (HR)-PKS family, and also contains a putative methyltransferase domain likely responsible for the addition of the methyl group to the OTA polyketide structure. AcOTApks is different from the ACpks protein that we previously described which showed an expression profile compatible with OTA production. We performed phylogenetic analyses of the β-ketosynthase and acyl-transferase domains of the OTA PKSs which had been identified and characterized in different OTA producing fungal species. The phylogenetic results were similar for both the two domains analyzed and showed that OTA PKS of A. carbonarius, Aspergillus niger, and Aspergillus ochraceus clustered in a monophyletic group with 100% bootstrap support suggesting a common origin, while the other OTA PKSs analyzed were phylogenetically distant. A qRT-PCR assay monitored AcOTApks expression during fungal growth and concomitant production of OTA by A. carbonarius in synthetic grape medium. A clear correlation between the expression profile of AcOTApks and kinetics of OTA production was observed with

  2. Identification and characterization of the polyketide synthase involved in ochratoxin A biosynthesis in Aspergillus carbonarius.

    PubMed

    Gallo, Antonia; Knox, Benjamin P; Bruno, Kenneth S; Solfrizzo, Michele; Baker, Scott E; Perrone, Giancarlo

    2014-06-01

    Ochratoxin A (OTA) is a potent mycotoxin produced by Aspergillus and Penicillium species and is a common contaminant of a wide variety of food commodities, with Aspergillus carbonarius being the main producer of OTA contamination in grapes and wine. The molecular structure of OTA comprises a dihydroisocoumarin ring linked to phenylalanine and, as shown in different producing fungal species, a polyketide synthase (PKS) is a component of the OTA biosynthetic pathway. Similar to observations in other filamentous ascomycetes, the genome sequence of A. carbonarius contains a large number of genes predicted to encode PKSs. In this work a pks gene identified within the putative OTA cluster of A. carbonarius, designated as AcOTApks, was inactivated and the resulting mutant strain was unable to produce OTA, confirming the role of AcOTApks in this biosynthetic pathway. AcOTApks protein is characteristic of the highly reduced (HR)-PKS family, and also contains a putative methyltransferase domain likely responsible for the addition of the methyl group to the OTA polyketide structure. AcOTApks is different from the ACpks protein that we previously described in A. carbonarius, which showed an expression profile compatible with OTA production. We performed phylogenetic analyses of the β-ketosynthase and acyl-transferase domains of the OTA PKSs that had been identified and characterized in different OTA producing fungal species. The phylogenetic results were similar for both domains analyzed and showed that OTA PKS of A. carbonarius, Aspergillus niger and Aspergillus ochraceus clustered in a monophyletic group with 100% bootstrap support suggesting a common origin, while the other OTA PKSs analyzed were phylogenetically distant. A quantitative RT-PCR assay monitored AcOTApks expression during fungal growth and concomitant production of OTA by A. carbonarius in synthetic grape medium. A clear correlation between the expression profile of AcOTApks and kinetics of OTA production was

  3. Geranyl diphosphate synthase molecules, and nucleic acid molecules encoding same

    SciTech Connect

    Croteau, Rodney Bruce; Burke, Charles Cullen

    2008-06-24

    In one aspect, the present invention provides isolated nucleic acid molecules that each encode a geranyl diphosphate synthase protein, wherein each isolated nucleic acid molecule hybridizes to a nucleic acid molecule consisting of the sequence set forth in SEQ ID NO:1 under conditions of 5.times.SSC at 45.degree. C. for one hour. The present invention also provides isolated geranyl diphosphate synthase proteins, and methods for altering the level of expression of geranyl diphosphate synthase protein in a host cell.

  4. Divinyl ether synthase gene and protein, and uses thereof

    DOEpatents

    Howe, Gregg A.; Itoh, Aya

    2011-09-13

    The present invention relates to divinyl ether synthase genes, proteins, and methods of their use. The present invention encompasses both native and recombinant wild-type forms of the synthase, as well as mutants and variant forms, some of which possess altered characteristics relative to the wild-type synthase. The present invention also relates to methods of using divinyl ether synthase genes and proteins, including in their expression in transgenic organisms and in the production of divinyl ether fatty acids, and to methods of suing divinyl ether fatty acids, including in the protection of plants from pathogens.

  5. Divinyl ether synthase gene, and protein and uses thereof

    DOEpatents

    Howe, Gregg A.; Itoh, Aya

    2006-12-26

    The present invention relates to divinyl ether synthase genes, proteins, and methods of their use. The present invention encompasses both native and recombinant wild-type forms of the synthase, as well as mutants and variant forms, some of which possess altered characteristics relative to the wild-type synthase. The present invention also relates to methods of using divinyl ether synthase genes and proteins, including in their expression in transgenic organisms and in the production of divinyl ether fatty acids, and to methods of suing divinyl ether fatty acids, including in the protection of plants from pathogens.

  6. Evolutinoary Consideration on 5-Aminolevulinate Synthase in Nature

    NASA Astrophysics Data System (ADS)

    Oh-Hama, Tamiko

    1997-08-01

    5-Aminolevulinic acid (ALA), a universal precursor of tetrapyrrole compounds can be synthesized by two pathways: the C5 (glutamate) pathway and ALA synthase. From the phylogenetic distribution it is shown that distribution of ALA synthase is restricted to the α subclass of purple bacteria in prokaryotes, and further distributed to mitochondria of eukaryotes. The monophyletic origin of bacterial and eukaryotic ALA synthase is shown by sequence analysis of the enzyme. Evolution of ALA synthase in the α subclass of purple bacteria is discussed in relation to the energy-generating and biosynthetic devices in subclasses of this bacteria.

  7. Vitis vinifera terpenoid cyclases: functional identification of two sesquiterpene synthase cDNAs encoding (+)-valencene synthase and (-)-germacrene D synthase and expression of mono- and sesquiterpene synthases in grapevine flowers and berries.

    PubMed

    Lücker, Joost; Bowen, Pat; Bohlmann, Jörg

    2004-10-01

    Valencene is a volatile sesquiterpene emitted from flowers of grapevine, Vitis vinifera L. A full-length cDNA from the cultivar Gewürztraminer was functionally expressed in Escherichia coli and found to encode valencene synthase (VvVal). The two major products formed by recombinant VvVal enzyme activity with farnesyl diphosphate (FPP) as substrate are (+)-valencene and (-)-7-epi-alpha-selinene. Grapevine valencene synthase is closely related to a second sesquiterpene synthase from this species, (-)-germacrene D synthase (VvGerD). VvVal and VvGerD cDNA probes revealed strong signals in Northern hybridizations with RNA isolated from grapevine flower buds. Transcript levels were lower in open pre-anthesis flowers, flowers after anthesis, or at early onset of fruit development. Similar results were obtained using a third probe, (-)-alpha-terpineol synthase, a monoterpenol synthase. Sesquiterpene synthase and monoterpene synthase transcripts were not detected in the mesocarp and exocarp during early stages of fruit development, but transcripts hybridizing with VvVal appeared during late ripening of the berries. Sesquiterpene synthase transcripts were also detected in young seeds. PMID:15464152

  8. Functional Prostacyclin Synthase Promoter Polymorphisms. Impact in Pulmonary Arterial Hypertension

    PubMed Central

    Cornelius, Amber R.; Lu, Xiao; Conklin, David S.; Del Rosario, Mark J.; Lowe, Anita M.; Elos, Mihret T.; Fettig, Lynsey M.; Wong, Randall E.; Hara, Naoko; Cogan, Joy D.; Phillips, John A.; Taylor, Matthew R.; Graham, Brian B.; Tuder, Rubin M.; Loyd, James E.; Geraci, Mark W.

    2014-01-01

    Rationale: Pulmonary arterial hypertension (PAH) is a progressive disease characterized by elevated pulmonary artery pressure, vascular remodeling, and ultimately right ventricular heart failure. PAH can have a genetic component (heritable PAH), most often through mutations of bone morphogenetic protein receptor 2, and idiopathic and associated forms. Heritable PAH is not completely penetrant within families, with approximately 20% concurrence of inactivating bone morphogenetic protein receptor 2 mutations and delayed onset of PAH disease. Because one of the treatment options is using prostacyclin analogs, we hypothesized that prostacyclin synthase promoter sequence variants associated with increased mRNA expression may play a protective role in the bone morphogenetic protein receptor 2 unaffected carriers. Objectives: To characterize the range of prostacyclin synthase promoter variants and assess their transcriptional activities in PAH-relevant cell types. To determine the distribution of prostacyclin synthase promoter variants in PAH, unaffected carriers in heritable PAH families, and control populations. Methods: Polymerase chain reaction approaches were used to genotype prostacyclin synthase promoter variants in more than 300 individuals. Prostacyclin synthase promoter haplotypes’ transcriptional activities were determined with luciferase reporter assays. Measurements and Main Results: We identified a comprehensive set of prostacyclin synthase promoter variants and tested their transcriptional activities in PAH-relevant cell types. We demonstrated differences of prostacyclin synthase promoter activities dependent on their haplotype. Conclusions: Prostacyclin synthase promoter sequence variants exhibit a range of transcriptional activities. We discovered a significant bias for more active prostacyclin synthase promoter variants in unaffected carriers as compared with affected patients with PAH. PMID:24605778

  9. Characterization of an Apis cerana cerana cytochrome P450 gene (AccCYP336A1) and its roles in oxidative stresses responses.

    PubMed

    Zhu, Ming; Zhang, Weixing; Liu, Feng; Chen, Xiaobo; Li, Han; Xu, Baohua

    2016-06-15

    Cytochrome P450 monooxygenases (P450), widely distributed multifunctional enzymes, that play an important role in the oxidative metabolism of endogenous compounds and xenobiotics. Studies have found that these enzymes show peroxidase-like activity and may thus be involved in protecting organisms against reactive oxygen species (ROS). In this work, Apis cerana cerana was used to investigate the molecular mechanisms of P450 family genes in resisting ROS damage. A cytochrome P450 gene was isolated, AccCYP336A1. The open reading frame (ORF) of AccCYP336A1 is 1491bp in length and encodes a predicted protein of 496 amino acids. The obtained amino acid sequence of AccCYP336A1 shared a high sequence identity with homologous proteins and contained the highly conserved features of this protein family. Quantitative real-time PCR (qRT-PCR) analysis showed that AccCYP336A1 was present in some fast developmental stages and had a higher expression in the epidermis than in other tissues. Additionally, the expression levels of AccCYP336A1 were up-regulated by cold (4°C), heat (42°C), ultraviolet (UV) radiation, H2O2 and pesticide (thiamethoxam, deltamethrin, methomyl and phoxim) treatments. These results were confirmed by the western blot assays. Furthermore, the recombinant AccCYP336A1 protein acted as an antioxidant that resisted paraquat-induced oxidative stress. Taken together, these results suggest that AccCYP336A1 may play a very significant role in antioxidant defense against ROS damage. PMID:26877110

  10. Mechanism of arginine regulation of acetylglutamate synthase, the first enzyme of arginine synthesis.

    PubMed

    Sancho-Vaello, Enea; Fernández-Murga, María L; Rubio, Vicente

    2009-01-01

    N-acetyl-L-glutamate synthase (NAGS), the first enzyme of arginine biosynthesis in bacteria/plants and an essential urea cycle activator in animals, is, respectively, arginine-inhibited and activated. Arginine binds to the hexameric ring-forming amino acid kinase (AAK) domain of NAGS. We show that arginine inhibits Pseudomonas aeruginosa NAGS by altering the functions of the distant, substrate binding/catalytic GCN5-related N-acetyltransferase (GNAT) domain, increasing K(m)(Glu), decreasing V(max) and triggering substrate inhibition by AcCoA. These effects involve centrally the interdomain linker, since we show that linker elongation or two-residue linker shortening hampers and mimics, respectively, arginine inhibition. We propose a regulatory mechanism in which arginine triggers the expansion of the hexameric NAGS ring, altering AAK-GNAT domain interactions, and the modulation by these interactions of GNAT domain functions, explaining arginine regulation. PMID:19084009

  11. Molecular characterization of the homo-phytochelatin synthase of soybean Glycine max: relation to phytochelatin synthase.

    PubMed

    Oven, Matjaz; Page, Jonathan E; Zenk, Meinhart H; Kutchan, Toni M

    2002-02-15

    The phytochelatin homologs homo-phytochelatins are heavy metal-binding peptides present in many legumes. To study the biosynthesis of these compounds, we have isolated and functionally expressed a cDNA GmhPCS1 encoding homo-phytochelatin synthase from Glycine max, a plant known to accumulate homo-phytochelatins rather than phytochelatins upon the exposure to heavy metals. The catalytic properties of GmhPCS1 were compared with the phytochelatin synthase AtPCS1 from Arabidopsis thaliana. When assayed only in the presence of glutathione, both enzymes catalyzed phytochelatin formation. GmhPCS1 accepted homoglutathione as the sole substrate for the synthesis of homo-phytochelatins whereas AtPCS1 did not. Homo-phytochelatin synthesis activity of both recombinant enzymes was significantly higher when glutathione was included in the reaction mixture. The incorporation of both glutathione and homoglutathione into homo-phytochelatin, n = 2, was demonstrated using GmhPCS1 and AtPCS1. In addition to bis(glutathionato)-metal complexes, various other metal-thiolates were shown to contribute to the activation of phytochelatin synthase. These complexes were not accepted as substrates by the enzyme, thereby suggesting that a recently proposed model of activation cannot fully explain the catalytic mechanism of phytochelatin synthase (Vatamaniuk, O. K., Mari, S., Lu, Y. P., and Rea, P. A. (2000) J. Biol. Chem. 275, 31451-31459). PMID:11706029

  12. Thymidylate synthase gene of herpesvirus ateles.

    PubMed Central

    Richter, J; Puchtler, I; Fleckenstein, B

    1988-01-01

    The putative thymidylate synthase (TS) gene of herpesvirus ateles, a T-lymphotropic tumor virus of New World primates, has a single large open reading frame encoding a polypeptide of 32.9 kilodaltons. The gene is transcribed into an unspliced 2.4-kilobase mRNA that is abundantly expressed late in virus replication. The AT-rich 5' untranslated leader sequence of TS mRNA in herpesvirus ateles-infected cells is remarkable in length (1,184 nucleotides), containing 29 minicistrons; this may indicate a role in translation regulation. Images PMID:3404583

  13. Engineering of chimeric class II polyhydroxyalkanoate synthases.

    PubMed

    Niamsiri, Nuttawee; Delamarre, Soazig C; Kim, Young-Rok; Batt, Carl A

    2004-11-01

    PHA synthase is a key enzyme involved in the biosynthesis of polyhydroxyalkanoates (PHAs). Using a combinatorial genetic strategy to create unique chimeric class II PHA synthases, we have obtained a number of novel chimeras which display improved catalytic properties. To engineer the chimeric PHA synthases, we constructed a synthetic phaC gene from Pseudomonas oleovorans (phaC1Po) that was devoid of an internal 540-bp fragment. Randomly amplified PCR products (created with primers based on conserved phaC sequences flanking the deleted internal fragment) were generated using genomic DNA isolated from soil and were substituted for the 540-bp internal region. The chimeric genes were expressed in a PHA-negative strain of Ralstonia eutropha, PHB(-)4 (DSM 541). Out of 1,478 recombinant clones screened for PHA production, we obtained five different chimeric phaC1Po genes that produced more PHA than the native phaC1Po. Chimeras S1-71, S4-8, S5-58, S3-69, and S3-44 exhibited 1.3-, 1.4-, 2.0-, 2.1-, and 3.0-fold-increased levels of in vivo activity, respectively. All of the mutants mediated the synthesis of PHAs with a slightly increased molar fraction of 3-hydroxyoctanoate; however, the weight-average molecular weights (Mw) of the PHAs in all cases remained almost the same. Based upon DNA sequence analyses, the various phaC fragments appear to have originated from Pseudomonas fluorescens and Pseudomonas aureofaciens. The amino acid sequence analyses showed that the chimeric proteins had 17 to 20 amino acid differences from the wild-type phaC1Po, and these differences were clustered in the same positions in the five chimeric clones. A threading model of PhaC1Po, developed based on homology of the enzyme to the Burkholderia glumae lipase, suggested that the amino acid substitutions found in the active chimeras were located mostly on the protein model surface. Thus, our combinatorial genetic engineering strategy proved to be broadly useful for improving the catalytic

  14. Appropriate antiplatelet and antithrombotic therapy in patients with acute coronary syndromes: recent updates to the ACC/AHA guidelines.

    PubMed

    Mehta, Shamir R

    2002-12-01

    Thrombosis is the most important pathological mechanism of acute coronary syndromes (ACS). In addition to standard antithrombotic treatment with aspirin and heparin, clopidogrel, glycoprotein IIb/IIIa inhibitors, and low-molecular-weight have a therapeutic benefit in ACS patients. Updated American College of Cardiology/American Heart Association guidelines for the management of ACS patients were published in mid-2002, and this article summarizes the rationale for the recommendations outlined in these guidelines for the use of antithrombotic and antiplatelet therapies. PMID:12668860

  15. Dose reduction in orthodontic lateral cephalography: dosimetric evaluation of a novel cephalographic thyroid protector (CTP) and anatomical cranial collimation (ACC)

    PubMed Central

    Rottke, D; van der Stelt, P F; Berkhout, W E R

    2015-01-01

    Objectives: To test the dose-reducing capabilities of a novel thyroid protection device and a recently introduced cranial collimator to be used in orthodontic lateral cephalography. Methods: Cephalographic thyroid protector (CTP) was designed to shield the thyroid while leaving the cervical vertebrae depicted. Using a RANDO® head phantom (The Phantom Laboratory, Salem, NY) equipped with dosemeters and a Proline XC (Planmeca, Helsinki, Finland) cephalograph, lateral cephalograms were taken, and the effective dose (ED) was calculated for four protocols: (1) without shielding; (2) with CTP; (3) with CTP and anatomical cranial collimator (ACC); and (4) with a thyroid collar (TC). Results: The ED for the respective protocols was (1) 8.51; (2) 5.39; (3) 3.50; and (4) 4.97 µSv. The organ dose for the thyroid was reduced from 30.17 to 4.50 µSv in Protocols 2 and 3 and to 3.33 µSv in Protocol 4. Conclusions: The use of just the CTP (Protocol 2) resulted in a 36.8% reduction of the ED of a lateral cephalogram. This was comparable to the classical TC (Protocol 4). A 58.8% reduction of the ED was obtained when combining CTP and ACC (Protocol 3). The dose to the radiosensitive thyroid gland was reduced by 85% in Protocols 2 and 3 and by 89% in Protocol 4. PMID:25564885

  16. Reward Sensitivity of ACC as an Intermediate Phenotype between DRD4-521T and Substance Misuse.

    PubMed

    Baker, Travis E; Stockwell, Tim; Barnes, Gordon; Haesevoets, Roderick; Holroyd, Clay B

    2016-03-01

    The development and expression of the midbrain dopamine system is determined in part by genetic factors that vary across individuals such that dopamine-related genes are partly responsible for addiction vulnerability. However, a complete account of how dopamine-related genes predispose individuals to drug addiction remains to be developed. Adopting an intermediate phenotype approach, we investigated whether reward-related electrophysiological activity of ACC-a cortical region said to utilize dopamine reward signals to learn the value of extended, context-specific sequences of goal-directed behaviors-mediates the influence of multiple dopamine-related functional polymorphisms over substance use. We used structural equation modeling to examine whether two related electrophysiological phenomena associated with the control and reinforcement learning functions of ACC-theta power and the reward positivity-mediated the relationship between the degree of substance misuse and genetic polymorphisms that regulate dopamine processing in frontal cortex. Substance use data were collected from 812 undergraduate students. One hundred ninety-six returned on a subsequent day to participate in an electrophysiological experiment and to provide saliva samples for DNA analysis. We found that these electrophysiological signals mediated a relationship between the DRD4-521T dopamine receptor genotype and substance misuse. Our results provide a theoretical framework that bridges the gap between genes and behavior in drug addiction and illustrate how future interventions might be individually tailored for specific genetic and neurocognitive profiles. PMID:26601911

  17. OpenACC acceleration of an unstructured CFD solver based on a reconstructed discontinuous Galerkin method for compressible flows

    DOE PAGESBeta

    Xia, Yidong; Lou, Jialin; Luo, Hong; Edwards, Jack; Mueller, Frank

    2015-02-09

    Here, an OpenACC directive-based graphics processing unit (GPU) parallel scheme is presented for solving the compressible Navier–Stokes equations on 3D hybrid unstructured grids with a third-order reconstructed discontinuous Galerkin method. The developed scheme requires the minimum code intrusion and algorithm alteration for upgrading a legacy solver with the GPU computing capability at very little extra effort in programming, which leads to a unified and portable code development strategy. A face coloring algorithm is adopted to eliminate the memory contention because of the threading of internal and boundary face integrals. A number of flow problems are presented to verify the implementationmore » of the developed scheme. Timing measurements were obtained by running the resulting GPU code on one Nvidia Tesla K20c GPU card (Nvidia Corporation, Santa Clara, CA, USA) and compared with those obtained by running the equivalent Message Passing Interface (MPI) parallel CPU code on a compute node (consisting of two AMD Opteron 6128 eight-core CPUs (Advanced Micro Devices, Inc., Sunnyvale, CA, USA)). Speedup factors of up to 24× and 1.6× for the GPU code were achieved with respect to one and 16 CPU cores, respectively. The numerical results indicate that this OpenACC-based parallel scheme is an effective and extensible approach to port unstructured high-order CFD solvers to GPU computing.« less

  18. OpenACC acceleration of an unstructured CFD solver based on a reconstructed discontinuous Galerkin method for compressible flows

    SciTech Connect

    Xia, Yidong; Lou, Jialin; Luo, Hong; Edwards, Jack; Mueller, Frank

    2015-02-09

    Here, an OpenACC directive-based graphics processing unit (GPU) parallel scheme is presented for solving the compressible Navier–Stokes equations on 3D hybrid unstructured grids with a third-order reconstructed discontinuous Galerkin method. The developed scheme requires the minimum code intrusion and algorithm alteration for upgrading a legacy solver with the GPU computing capability at very little extra effort in programming, which leads to a unified and portable code development strategy. A face coloring algorithm is adopted to eliminate the memory contention because of the threading of internal and boundary face integrals. A number of flow problems are presented to verify the implementation of the developed scheme. Timing measurements were obtained by running the resulting GPU code on one Nvidia Tesla K20c GPU card (Nvidia Corporation, Santa Clara, CA, USA) and compared with those obtained by running the equivalent Message Passing Interface (MPI) parallel CPU code on a compute node (consisting of two AMD Opteron 6128 eight-core CPUs (Advanced Micro Devices, Inc., Sunnyvale, CA, USA)). Speedup factors of up to 24× and 1.6× for the GPU code were achieved with respect to one and 16 CPU cores, respectively. The numerical results indicate that this OpenACC-based parallel scheme is an effective and extensible approach to port unstructured high-order CFD solvers to GPU computing.

  19. 2013 ACC/AHA guideline recommends fixed-dose strategies instead of targeted goals to lower blood cholesterol.

    PubMed

    Smith, Sidney C; Grundy, Scott M

    2014-08-12

    The American College of Cardiology (ACC)/American Heart Association (AHA) Task Force on Practice Guidelines recently issued the 2013 ACC/AHA Guideline on the Treatment of Blood Cholesterol to Reduce Atherosclerotic Cardiovascular Risk in Adults. This new guideline endorses a paradigm shift in strategies for reducing atherosclerotic cardiovascular disease (ASCVD) events by lowering blood cholesterol. Whereas previous guidelines focused on therapy to decrease low-density lipoprotein and non-high-density lipoprotein cholesterol to specific target levels, the new guideline instead proposes implementation of cholesterol-lowering treatment using evidenced-based intensity of statin therapy without such targets. The guideline also provides a new risk estimator for primary prevention decisions, including stroke outcomes and data on African Americans, which will significantly increase the number of patients recommended for outcome-related benefits of cholesterol-lowering therapy. The first section of this paper reviews the process by which the task force developed the new evidence-based guideline, the major findings and recommendations, and their implications. The second section primarily focuses on the question of how much low-density lipoprotein cholesterol should be lowered and on additional considerations in risk assessment. PMID:25104531

  20. Novel family of terpene synthases evolved from trans-isoprenyl diphosphate synthases in a flea beetle

    PubMed Central

    Beran, Franziska; Rahfeld, Peter; Luck, Katrin; Nagel, Raimund; Vogel, Heiko; Wielsch, Natalie; Irmisch, Sandra; Ramasamy, Srinivasan; Gershenzon, Jonathan; Heckel, David G.; Köllner, Tobias G.

    2016-01-01

    Sesquiterpenes play important roles in insect communication, for example as pheromones. However, no sesquiterpene synthases, the enzymes involved in construction of the basic carbon skeleton, have been identified in insects to date. We investigated the biosynthesis of the sesquiterpene (6R,7S)-himachala-9,11-diene in the crucifer flea beetle Phyllotreta striolata, a compound previously identified as a male-produced aggregation pheromone in several Phyllotreta species. A (6R,7S)-himachala-9,11-diene–producing sesquiterpene synthase activity was detected in crude beetle protein extracts, but only when (Z,E)-farnesyl diphosphate [(Z,E)-FPP] was offered as a substrate. No sequences resembling sesquiterpene synthases from plants, fungi, or bacteria were found in the P. striolata transcriptome, but we identified nine divergent putative trans-isoprenyl diphosphate synthase (trans-IDS) transcripts. Four of these putative trans-IDSs exhibited terpene synthase (TPS) activity when heterologously expressed. Recombinant PsTPS1 converted (Z,E)-FPP to (6R,7S)-himachala-9,11-diene and other sesquiterpenes observed in beetle extracts. RNAi-mediated knockdown of PsTPS1 mRNA in P. striolata males led to reduced emission of aggregation pheromone, confirming a significant role of PsTPS1 in pheromone biosynthesis. Two expressed enzymes showed genuine IDS activity, with PsIDS1 synthesizing (E,E)-FPP, whereas PsIDS3 produced neryl diphosphate, (Z,Z)-FPP, and (Z,E)-FPP. In a phylogenetic analysis, the PsTPS enzymes and PsIDS3 were clearly separated from a clade of known coleopteran trans-IDS enzymes including PsIDS1 and PsIDS2. However, the exon–intron structures of IDS and TPS genes in P. striolata are conserved, suggesting that this TPS gene family evolved from trans-IDS ancestors. PMID:26936952

  1. Novel family of terpene synthases evolved from trans-isoprenyl diphosphate synthases in a flea beetle.

    PubMed

    Beran, Franziska; Rahfeld, Peter; Luck, Katrin; Nagel, Raimund; Vogel, Heiko; Wielsch, Natalie; Irmisch, Sandra; Ramasamy, Srinivasan; Gershenzon, Jonathan; Heckel, David G; Köllner, Tobias G

    2016-03-15

    Sesquiterpenes play important roles in insect communication, for example as pheromones. However, no sesquiterpene synthases, the enzymes involved in construction of the basic carbon skeleton, have been identified in insects to date. We investigated the biosynthesis of the sesquiterpene (6R,7S)-himachala-9,11-diene in the crucifer flea beetle Phyllotreta striolata, a compound previously identified as a male-produced aggregation pheromone in several Phyllotreta species. A (6R,7S)-himachala-9,11-diene-producing sesquiterpene synthase activity was detected in crude beetle protein extracts, but only when (Z,E)-farnesyl diphosphate [(Z,E)-FPP] was offered as a substrate. No sequences resembling sesquiterpene synthases from plants, fungi, or bacteria were found in the P. striolata transcriptome, but we identified nine divergent putative trans-isoprenyl diphosphate synthase (trans-IDS) transcripts. Four of these putative trans-IDSs exhibited terpene synthase (TPS) activity when heterologously expressed. Recombinant PsTPS1 converted (Z,E)-FPP to (6R,7S)-himachala-9,11-diene and other sesquiterpenes observed in beetle extracts. RNAi-mediated knockdown of PsTPS1 mRNA in P. striolata males led to reduced emission of aggregation pheromone, confirming a significant role of PsTPS1 in pheromone biosynthesis. Two expressed enzymes showed genuine IDS activity, with PsIDS1 synthesizing (E,E)-FPP, whereas PsIDS3 produced neryl diphosphate, (Z,Z)-FPP, and (Z,E)-FPP. In a phylogenetic analysis, the PsTPS enzymes and PsIDS3 were clearly separated from a clade of known coleopteran trans-IDS enzymes including PsIDS1 and PsIDS2. However, the exon-intron structures of IDS and TPS genes in P. striolata are conserved, suggesting that this TPS gene family evolved from trans-IDS ancestors. PMID:26936952

  2. 1-Aminocyclopropane-1-carboxylic acid (ACC) deaminase-containing rhizobacteria protect Ocimum sanctum plants during waterlogging stress via reduced ethylene generation.

    PubMed

    Barnawal, Deepti; Bharti, Nidhi; Maji, Deepamala; Chanotiya, Chandan Singh; Kalra, Alok

    2012-09-01

    Ocimum sanctum grown as rain-fed crop, is known to be poorly adapted to waterlogged conditions. Many a times the crop suffers extreme damages because of anoxia and excessive ethylene generation due to waterlogging conditions present under heavy rain. The usefulness of 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase-containing plant growth promoting rhizobacteria was investigated under waterlogging stress. The comparison of herb yield and stress induced biochemical changes of waterlogged and non-waterlogged plants with and without ACC deaminase-containing microbiological treatments were monitored in this study. Ten plant growth promoting rhizobacteria strains containing ACC-deaminase were isolated and characterized. Four selected isolates Fd2 (Achromobacter xylosoxidans), Bac5 (Serratia ureilytica), Oci9 (Herbaspirillum seropedicae) and Oci13 (Ochrobactrum rhizosphaerae) had the potential to protect Ocimum plants from flood induced damage under waterlogged glass house conditions. Pot experiments were conducted to evaluate the potential of these ACC deaminase-containing selected strains for reducing the yield losses caused by waterlogging conditions. Bacterial treatments protected plants from waterlogging induced detrimental changes like stress ethylene production, reduced chlorophyll concentration, higher lipid peroxidation, proline concentration and reduced foliar nutrient uptake. Fd2 (A. xylosoxidans) induced maximum waterlogging tolerance as treated waterlogged plants recorded maximum growth and herb yield (46.5% higher than uninoculated waterlogged plants) with minimum stress ethylene levels (53% lower ACC concentration as compared to waterlogged plants without bacterial inoculation) whereas under normal non-waterlogged conditions O. rhizosphaerae was most effective in plant growth promotion. PMID:22846334

  3. The ac53, ac78, ac101, and ac103 Genes Are Newly Discovered Core Genes in the Family Baculoviridae

    PubMed Central

    Garavaglia, Matías Javier; Miele, Solange Ana Belén; Iserte, Javier Alonso; Belaich, Mariano Nicolás

    2012-01-01

    The family Baculoviridae is a large group of insect viruses containing circular double-stranded DNA genomes of 80 to 180 kbp, which have broad biotechnological applications. A key feature to understand and manipulate them is the recognition of orthology. However, the differences in gene contents and evolutionary distances among the known members of this family make it difficult to assign sequence orthology. In this study, the genome sequences of 58 baculoviruses were analyzed, with the aim to detect previously undescribed core genes because of their remote homology. A routine based on Multi PSI-Blast/tBlastN and Multi HaMStR allowed us to detect 31 of 33 accepted core genes and 4 orthologous sequences in the Baculoviridae which were not described previously. Our results show that the ac53, ac78, ac101 (p40), and ac103 (p48) genes have orthologs in all genomes and should be considered core genes. Accordingly, there are 37 orthologous genes in the family Baculoviridae. PMID:22933288

  4. Simple Equipment for Imaging AC.

    ERIC Educational Resources Information Center

    Kamata, Masahiro; Anayama, Takayuki

    2003-01-01

    Presents an effective way to demonstrate the difference between direct current and alternating current using red and green LEDs. Describes how to make a tool that shows how an AC voltage changes with time using the afterimage effect of the LEDs. (Author/NB)

  5. Semiconductor ac static power switch

    NASA Technical Reports Server (NTRS)

    Vrancik, J.

    1968-01-01

    Semiconductor ac static power switch has long life and high reliability, contains no moving parts, and operates satisfactorily in severe environments, including high vibration and shock conditions. Due to their resistance to shock and vibration, static switches are used where accidental switching caused by mechanical vibration or shock cannot be tolerated.

  6. Energy saving in ac generators

    NASA Technical Reports Server (NTRS)

    Nola, F. J.

    1980-01-01

    Circuit cuts no-load losses, without sacrificing full-load power. Phase-contro circuit includes gate-controlled semiconductor switch that cuts off applied voltage for most of ac cycle if generator idling. Switch "on" time increases when generator is in operation.

  7. Torque generation mechanism of ATP synthase

    NASA Astrophysics Data System (ADS)

    Miller, John; Maric, Sladjana; Scoppa, M.; Cheung, M.

    2010-03-01

    ATP synthase is a rotary motor that produces adenosine triphosphate (ATP), the chemical currency of life. Our proposed electric field driven torque (EFT) model of FoF1-ATP synthase describes how torque, which scales with the number of c-ring proton binding sites, is generated by the proton motive force (pmf) across the mitochondrial inner membrane. When Fo is coupled to F1, the model predicts a critical pmf to drive ATP production. In order to fully understand how the electric field resulting from the pmf drives the c-ring to rotate, it is important to examine the charge distributions in the protonated c-ring and a-subunit containing the proton channels. Our calculations use a self-consistent field approach based on a refinement of reported structural data. The results reveal changes in pKa for key residues on the a-subunit and c-ring, as well as titration curves and protonation state energy diagrams. Health implications will be briefly discussed.

  8. ATP synthase: a tentative structural model.

    PubMed

    Engelbrecht, S; Junge, W

    1997-09-15

    Adenosine triphosphate (ATP) synthase produces ATP from ADP and inorganic phosphate at the expense of proton- or sodium-motive force across the respective coupling membrane in Archaea, Bacteria and Eucarya. Cation flow through the intrinsic membrane portion of this enzyme (Fo, subunits ab2c9-12) and substrate turnover in the headpiece (F1, subunits alpha3beta3 gammadeltaepsilon) are mechanically coupled by the rotation of subunit gamma in the center of the catalytic hexagon of subunits (alphabeta)3 in F1. ATP synthase is the smallest rotatory engine in nature. With respect to the headpiece alone, it probably operates with three steps. Partial structures of six out of its at least eight different subunits have been published and a 3-dimensional structure is available for the assembly (alphabeta)3gamma. In this article, we review the available structural data and build a tentative topological model of the holoenzyme. The rotor portion is proposed to consist of a wheel of at least nine copies of subunits c, epsilon and a portion of gamma as a spoke, and another portion of gamma as a crankshaft. The stator is made up from a, the transmembrane portion of b2, delta and the catalytic hexagon of (alphabeta)3. As an educated guess, the model may be of heuristic value for ongoing studies on this fascinating electrochemical-to-mechanical-to-chemical transducer. PMID:9323021

  9. Loss of LRPPRC causes ATP synthase deficiency.

    PubMed

    Mourier, Arnaud; Ruzzenente, Benedetta; Brandt, Tobias; Kühlbrandt, Werner; Larsson, Nils-Göran

    2014-05-15

    Defects of the oxidative phosphorylation system, in particular of cytochrome-c oxidase (COX, respiratory chain complex IV), are common causes of Leigh syndrome (LS), which is a rare neurodegenerative disorder with severe progressive neurological symptoms that usually present during infancy or early childhood. The COX-deficient form of LS is commonly caused by mutations in genes encoding COX assembly factors, e.g. SURF1, SCO1, SCO2 or COX10. However, other mutations affecting genes that encode proteins not directly involved in COX assembly can also cause LS. The leucine-rich pentatricopeptide repeat containing protein (LRPPRC) regulates mRNA stability, polyadenylation and coordinates mitochondrial translation. In humans, mutations in Lrpprc cause the French Canadian type of LS. Despite the finding that LRPPRC deficiency affects the stability of most mitochondrial mRNAs, its pathophysiological effect has mainly been attributed to COX deficiency. Surprisingly, we show here that the impaired mitochondrial respiration and reduced ATP production observed in Lrpprc conditional knockout mouse hearts is caused by an ATP synthase deficiency. Furthermore, the appearance of inactive subassembled ATP synthase complexes causes hyperpolarization and increases mitochondrial reactive oxygen species production. Our findings shed important new light on the bioenergetic consequences of the loss of LRPPRC in cardiac mitochondria. PMID:24399447

  10. Activities and regulation of peptidoglycan synthases

    PubMed Central

    Egan, Alexander J. F.; Biboy, Jacob; van't Veer, Inge; Breukink, Eefjan; Vollmer, Waldemar

    2015-01-01

    Peptidoglycan (PG) is an essential component in the cell wall of nearly all bacteria, forming a continuous, mesh-like structure, called the sacculus, around the cytoplasmic membrane to protect the cell from bursting by its turgor. Although PG synthases, the penicillin-binding proteins (PBPs), have been studied for 70 years, useful in vitro assays for measuring their activities were established only recently, and these provided the first insights into the regulation of these enzymes. Here, we review the current knowledge on the glycosyltransferase and transpeptidase activities of PG synthases. We provide new data showing that the bifunctional PBP1A and PBP1B from Escherichia coli are active upon reconstitution into the membrane environment of proteoliposomes, and that these enzymes also exhibit DD-carboxypeptidase activity in certain conditions. Both novel features are relevant for their functioning within the cell. We also review recent data on the impact of protein–protein interactions and other factors on the activities of PBPs. As an example, we demonstrate a synergistic effect of multiple protein–protein interactions on the glycosyltransferase activity of PBP1B, by its cognate lipoprotein activator LpoB and the essential cell division protein FtsN. PMID:26370943

  11. Discovery of DF-461, a Potent Squalene Synthase Inhibitor

    PubMed Central

    2013-01-01

    We report the development of a new trifluoromethyltriazolobenzoxazepine series of squalene synthase inhibitors. Structure–activity studies and pharmacokinetics optimization on this series led to the identification of compound 23 (DF-461), which exhibited potent squalene synthase inhibitory activity, high hepatic selectivity, excellent rat hepatic cholesterol synthesis inhibitory activity, and plasma lipid lowering efficacy in nonrodent repeated dose studies. PMID:24900587

  12. Probing myo-inositol 1-phosphate synthase with multisubstrate adducts

    PubMed Central

    Deranieh, Rania M.; Greenberg, Miriam L.; Le Calvez, Pierre-B.; Mooney, Maura C.; Migaud, Marie E.

    2015-01-01

    The synthesis of a series of carbohydrate-nucleotide hybrids, designed to be multisubstrate adducts mimicking myo-inositol 1-phosphate synthase first oxidative transition state, is reported. Their ability to inhibit the synthase has been assessed and results have been rationalised computationally to estimate their likely binding mode. PMID:23132282

  13. Ubiquitination and filamentous structure of cytidine triphosphate synthase.

    PubMed

    Pai, Li-Mei; Wang, Pei-Yu; Lin, Wei-Cheng; Chakraborty, Archan; Yeh, Chau-Ting; Lin, Yu-Hung

    2016-07-01

    Living organisms respond to nutrient availability by regulating the activity of metabolic enzymes. Therefore, the reversible post-translational modification of an enzyme is a common regulatory mechanism for energy conservation. Recently, cytidine-5'-triphosphate (CTP) synthase was discovered to form a filamentous structure that is evolutionarily conserved from flies to humans. Interestingly, induction of the formation of CTP synthase filament is responsive to starvation or glutamine depletion. However, the biological roles of this structure remain elusive. We have recently shown that ubiquitination regulates CTP synthase activity by promoting filament formation in Drosophila ovaries during endocycles. Intriguingly, although the ubiquitination process was required for filament formation induced by glutamine depletion, CTP synthase ubiquitination was found to be inversely correlated with filament formation in Drosophila and human cell lines. In this article, we discuss the putative dual roles of ubiquitination, as well as its physiological implications, in the regulation of CTP synthase structure. PMID:27116391

  14. pACC1 peptide loaded chitosan nanoparticles induces apoptosis via reduced fatty acid synthesis in MDA-MB-231 cells

    NASA Astrophysics Data System (ADS)

    Kaliaperumal, Jagatheesh; Hari, Natarajan; Pavankumar, Padarthi; Elangovan, Namasivayam

    2015-06-01

    The development of formulations with therapeutic peptides has been restricted to poor cell penetration and in this attempt; we developed pACC1 peptide loaded chitosan nanoparticles. The prepared nanoparticles were characterized with FT-IR, XRD, SEM and TEM. In addition, the suitable formulation was evaluated for hemocompatibility, plasma stability and embryo toxicity using Danio rerio embryo model. The results showed that pACC1 peptide loaded chitosan nanoparticles were compatible with plasma. They possess sustained release pattern and also found to be safe up to 300 mg/L in embryo toxicity tests. Cytotoxicity assays with MDA-MB-231 cell lines suggested that, pACC1 peptide loaded chitosan nanoparticles were capable of enhanced cellular penetration and reduced palmitic acid content, which was confirmed by H1 NMR. Hence, these nanoparticles could be employed as excellent adjuvant therapeutics while treating solid tumors with multi-drug resistance.

  15. pACC1 peptide loaded chitosan nanoparticles induces apoptosis via reduced fatty acid synthesis in MDA-MB-231 cells

    NASA Astrophysics Data System (ADS)

    Kaliaperumal, Jagatheesh; Hari, Natarajan; Pavankumar, Padarthi; Elangovan, Namasivayam

    2016-06-01

    The development of formulations with therapeutic peptides has been restricted to poor cell penetration and in this attempt; we developed pACC1 peptide loaded chitosan nanoparticles. The prepared nanoparticles were characterized with FT-IR, XRD, SEM and TEM. In addition, the suitable formulation was evaluated for hemocompatibility, plasma stability and embryo toxicity using Danio rerio embryo model. The results showed that pACC1 peptide loaded chitosan nanoparticles were compatible with plasma. They possess sustained release pattern and also found to be safe up to 300 mg/L in embryo toxicity tests. Cytotoxicity assays with MDA-MB-231 cell lines suggested that, pACC1 peptide loaded chitosan nanoparticles were capable of enhanced cellular penetration and reduced palmitic acid content, which was confirmed by H1 NMR. Hence, these nanoparticles could be employed as excellent adjuvant therapeutics while treating solid tumors with multi-drug resistance.

  16. Voltage controller/current limiter for ac

    NASA Technical Reports Server (NTRS)

    Wu, T. T.

    1980-01-01

    Circuit protects ac power systems for overload failures, limits power surge and short-circuit currents to 150 percent of steady state level, regulates ac output voltage, and soft starts loads. Limiter generates dc error signal in response to line fluctuations and dumps power when overload is reached. Device is inserted between ac source and load.

  17. A Comparison of the Effects of Neuronal Nitric Oxide Synthase and Inducible Nitric Oxide Synthase Inhibition on Cartilage Damage

    PubMed Central

    Gokay, Nevzat Selim; Yilmaz, Ibrahim; Demiroz, Ahu Senem; Gokce, Alper; Dervisoglu, Sergülen; Gokay, Banu Vural

    2016-01-01

    The objective of this study was to investigate the effects of selective inducible nitric oxide synthase and neuronal nitric oxide synthase inhibitors on cartilage regeneration. The study involved 27 Wistar rats that were divided into five groups. On Day 1, both knees of 3 rats were resected and placed in a formalin solution as a control group. The remaining 24 rats were separated into 4 groups, and their right knees were surgically damaged. Depending on the groups, the rats were injected with intra-articular normal saline solution, neuronal nitric oxide synthase inhibitor 7-nitroindazole (50 mg/kg), inducible nitric oxide synthase inhibitor amino-guanidine (30 mg/kg), or nitric oxide precursor L-arginine (200 mg/kg). After 21 days, the right and left knees of the rats were resected and placed in formalin solution. The samples were histopathologically examined by a blinded evaluator and scored on 8 parameters. Although selective neuronal nitric oxide synthase inhibition exhibited significant (P = 0.044) positive effects on cartilage regeneration following cartilage damage, it was determined that inducible nitric oxide synthase inhibition had no statistically significant effect on cartilage regeneration. It was observed that the nitric oxide synthase activation triggered advanced arthrosis symptoms, such as osteophyte formation. The fact that selective neuronal nitric oxide synthase inhibitors were observed to have mitigating effects on the severity of the damage may, in the future, influence the development of new agents to be used in the treatment of cartilage disorders. PMID:27382570

  18. Light/Dark Profiles of Sucrose Phosphate Synthase, Sucrose Synthase, and Acid Invertase in Leaves of Sugar Beets

    PubMed Central

    Vassey, Terry L.

    1989-01-01

    The activity of sucrose phosphate synthase, sucrose synthase, and acid invertase was monitored in 1- to 2-month-old sugar beet (Beta vulgaris L.) leaves. Sugar beet leaves achieve full laminar length in 13 days. Therefore, leaves were harvested at 2-day intervals for 15 days. Sucrose phosphate synthase activity was not detectable for 6 days in the dark-grown leaves. Once activity was measurable, sucrose phosphate synthase activity never exceeded half that observed in the light-grown leaves. After 8 days in the dark, leaves which were illuminated for 30 minutes showed no significant change in sucrose phosphate synthase activity. Leaves illuminated for 24 hours after 8 days in darkness, however, recovered sucrose phosphate synthase activity to 80% of that of normally grown leaves. Sucrose synthase and acid invertase activity in the light-grown leaves both increased for the first 7 days and then decreased as the leaves matured. In contrast, the activity of sucrose synthase oscillated throughout the growth period in the dark-grown leaves. Acid invertase activity in the dark-grown leaves seemed to be the same as the activity found in the light-grown leaves. PMID:16666537

  19. Functional Contribution of Chorismate Synthase, Anthranilate Synthase, and Chorismate Mutase to Penetration Resistance in Barley-Powdery Mildew Interactions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plant processes resulting from primary or secondary metabolism have been hypothesized to contribute to defense against microbial attack. Barley chorismate synthase (HvCS), anthranilate synthase alpha subunit 2 (HvASa2) and chorismate mutase 1 (HvCM1) occupy pivotal branch-points downstream of the s...

  20. Studies on Plant Growth Promoting Properties of Fruit-Associated Bacteria from Elettaria cardamomum and Molecular Analysis of ACC Deaminase Gene.

    PubMed

    Jasim, B; Anish, Mathew Chacko; Shimil, Vellakudiyan; Jyothis, Mathew; Radhakrishnan, E K

    2015-09-01

    Endophytic microorganisms have been reported to have diverse plant growth promoting mechanisms including phosphate solubilization, N2 fixation, production of phyto-hormones and ACC (1-aminocyclopropane-1-carboxylate) deaminase and antiphyto-pathogenic properties. Among these, ACC deaminase production is very important because of its regulatory effect on ethylene which is a stress hormone with precise role in the control of fruit development and ripening. However, distribution of these properties among various endophytic bacteria associated with fruit tissue and its genetic basis is least investigated. In the current study, 11 endophytic bacteria were isolated and identified from the fruit tissue of Elettaria cardamomum and were studied in detail for various plant growth promoting properties especially ACC deaminase activity using both culture-based and PCR-based methods. PCR-based screening identified the isolates EcB 2 (Pantoea sp.), EcB 7 (Polaromonas sp.), EcB 9 (Pseudomonas sp.), EcB 10 (Pseudomonas sp.) and EcB 11 (Ralstonia sp.) as positive for ACC deaminase. The PCR products were further subjected to sequence analysis which proved the similarity of the sequences identified in the study with ACC deaminase sequences reported from other sources. The detailed bioinformatic analysis of the sequence including homology-based modelling and molecular docking confirmed the sequences to have ACC deaminase activity. The docking of the modelled proteins was done using patch dock, and the detailed scrutiny of the protein ligand interaction revealed conservation of key amino acids like Lys51, Ser78, Tyr268 and Tyr294 which play important role in the enzyme activity. These suggest the possible regulatory effect of these isolates on fruit physiology. PMID:26164855

  1. Expression of potato S-adenosyl-L-methionine synthase (SbSAMS) gene altered developmental characteristics and stress responses in transgenic Arabidopsis plants.

    PubMed

    Kim, Sun Hee; Kim, Sang Hyon; Palaniyandi, Sasikumar Arunachalam; Yang, Seung Hwan; Suh, Joo-Won

    2015-02-01

    S-adenosyl-L-methionine (SAM) synthase (SAMS) catalyze the biosynthesis of SAM, which is a precursor for ethylene and polyamines, and a methyl donor for a number of biomolecules. A full-length cDNA of SAMS from Solanum brevidens was expressed in Arabidopsis thaliana to study its physiological function. RT-PCR analysis showed that SbSAMS expression was enhanced significantly in S. brevidens leaves upon treatment with salt, mannitol, ethephon, IAA and ABA. The transgenic SbSAMS overexpression lines accumulated higher levels S-adenosyl homocysteine (SAHC) and ethylene concomitantly with increased SAM level. Expression levels of genes related to ethylene biosynthesis such as ACC synthase, but not polyamine biosynthesis genes were enhanced in SbSAMS overexpressing Arabidopsis lines. In addition, ABA responsive, wound and pathogen-inducible genes were upregulated in SbSAMS transgenic Arabidopsis plants. Transgenic Arabidopsis lines exhibited higher salt and drought stress tolerance compared to those of vector control. Based on these results we conclude that SbSAMS is expressed under abiotic stress to produce SAM as a broad-spectrum signal molecule to upregulate stress-related genes including ethylene and ABA biosynthetic pathway genes responsible for ABA, pathogen and wound responses. PMID:25559387

  2. Chalcone synthase as a reporter in virus-induced gene silencing studies of flower senescence.

    PubMed

    Chen, Jen-Chih; Jiang, Cai-Zhong; Gookin, Timothy E; Hunter, Donald A; Clark, David G; Reid, Michael S

    2004-07-01

    Agrobacterium-mediated infection of petunia (Petunia hybrida) plants with tobacco rattle virus (TRV) bearing fragments of Petunia genes resulted in systemic infection and virus-induced gene silencing (VIGS) of the homologous host genes. Infection with TRV containing a phytoene desaturase (PDS) fragment resulted in reduced abundance of PDS transcripts and typical photobleaching of photosynthetic tissues. Infection with TRV containing a chalcone synthase (CHS) fragment resulted in silencing of anthocyanin production in infected flowers. The silencing phenotype ranged from scattered white spots on the normal purple background to entirely white flowers. Symptoms in the V26 cultivar were a diffuse mosaic, but infection of some purple-flowered commercial cultivars resulted in large white sectors and even entirely white flowers. Abundance of CHS transcripts in the white flowers was less than 4% of that in purple flowers on the same plant. Infection with TRV containing a tandem construct of PDS and CHS resulted in leaf photobleaching and white patterns on the flowers. Transcripts of CHS and PDS were reduced both in leaves and in flowers confirming simultaneous silencing of both genes by the tandem construct. We tested the effects of infection with TRV containing CHS and a fragment of a petunia gene encoding for 1-aminocyclopropane-1-carboxylate oxidase (ACO4) Abundance of transcripts encoding ACO4 and ACO1 were reduced (by 5% and 20%, respectively) in infected flowers. Whether the flowers were treated with ACC or pollinated, the white (silenced) flowers or flower sectors produced less ethylene and senesced later than purple (non-silenced) tissues. These results indicate the value of VIGS with tandem constructs containing CHS as reporter and a target gene as a tool for examining the function of floral-associated genes. PMID:15604697

  3. Identification of sucrose synthase in nonphotosynthetic bacteria and characterization of the recombinant enzymes.

    PubMed

    Diricks, Margo; De Bruyn, Frederik; Van Daele, Paul; Walmagh, Maarten; Desmet, Tom

    2015-10-01

    Sucrose synthase (SuSy) catalyzes the reversible conversion of sucrose and a nucleoside diphosphate into fructose and nucleotide (NDP)-glucose. To date, only SuSy's from plants and cyanobacteria, both photosynthetic organisms, have been characterized. Here, four prokaryotic SuSy enzymes from the nonphotosynthetic organisms Nitrosomonas Europaea (SuSyNe), Acidithiobacillus caldus (SuSyAc), Denitrovibrio acetiphilus (SusyDa), and Melioribacter roseus (SuSyMr) were recombinantly expressed in Escherichia coli and thoroughly characterized. The purified enzymes were found to display high-temperature optima (up to 80 °C), high activities (up to 125 U/mg), and high thermostability (up to 15 min at 60 °C). Furthermore, SuSyAc, SuSyNe, and SuSyDa showed a clear preference for ADP as nucleotide, as opposed to plant SuSy's which prefer UDP. A structural and mutational analysis was performed to elucidate the difference in NDP preference between eukaryotic and prokaryotic SuSy's. Finally, the physiological relevance of this enzyme specificity is discussed in the context of metabolic pathways and genomic organization. PMID:25846332

  4. Hyaluronan synthases and hyaluronidases in nasal polyps.

    PubMed

    Panogeorgou, T; Tserbini, E; Filou, S; Vynios, D H; Naxakis, S S; Papadas, T A; Goumas, P D; Mastronikolis, N S

    2016-07-01

    Nasal polyps (NPs) are benign lesions of nasal and paranasal sinuses mucosa affecting 1-4 % of all adults. Nasal polyposis affects the quality of patient's life as it causes nasal obstruction, postnasal drainage, purulent nasal discharge, hyposmia or anosmia, chronic sinusitis, facial pain and snoring. Without treatment, the disease can alter the craniofacial skeleton in cases of extended growth of polyps. The development of NPs is caused by the hyperplasia of nasal or paranasal sinuses mucosa, and edema of extracellular matrix. This is usually the result of high concentration of high molecular mass hyaluronan (HA) which is either overproduced or accumulated from blood supply. The size of HA presents high diversity and, especially in pathologic conditions, chains of low molecular mass can be observed. In NPs, chains of about 200 kDa have been identified and considered to be responsible for the inflammation. The purpose of the present study was the investigation, in NPs and normal nasal mucosa (NM), of the expression of the wild-type and alternatively spliced forms of hyaluronidases, their immunolocalization, and the expression of HA synthases to examine the isoform(s) responsible for the increased amounts of HA in NPs. Hyaluronidases' presence was examined on mRNA (RT-PCR analysis) and protein (immunohistochemistry) levels. Hyaluronan synthases' presence was examined on mRNA levels. Hyaluronidases were localized in the cytoplasm of epithelial and inflammatory cells, as well as in the matrix. On mRNA level, it was found that hyal-1-wt was decreased in NPs compared to NM and hyal-1-v3, -v4 and -v5 were substantially increased. Moreover, HAS2 and HAS3 were the only hyaluronan synthases detected, the expression of which was almost similar in NPs and NM. Overall, the results of the present study support that hyaluronidases are the main enzymes responsible for the decreased size of hyaluronan observed in NPs; thus they behave as inflammatory agents. Therefore, they

  5. Heterologous expression in Saccharopolyspora erythraea of a pentaketide synthase derived from the spinosyn polyketide synthase.

    PubMed

    Martin, Christine J; Timoney, Máire C; Sheridan, Rose M; Kendrew, Steven G; Wilkinson, Barrie; Staunton, James C; Leadlay, Peter F

    2003-12-01

    A truncated version of the spinosyn polyketide synthase comprising the loading module and the first four extension modules fused to the erythromycin thioesterase domain was expressed in Saccharopolyspora erythraea. A novel pentaketide lactone product was isolated, identifying cryptic steps of spinosyn biosynthesis and indicating the potential of this approach for the biosynthetic engineering of spinosyn analogues. A pathway for the formation of the tetracyclic spinosyn aglycone is proposed. PMID:14685317

  6. Simultaneous distribution of AC and DC power

    DOEpatents

    Polese, Luigi Gentile

    2015-09-15

    A system and method for the transport and distribution of both AC (alternating current) power and DC (direct current) power over wiring infrastructure normally used for distributing AC power only, for example, residential and/or commercial buildings' electrical wires is disclosed and taught. The system and method permits the combining of AC and DC power sources and the simultaneous distribution of the resulting power over the same wiring. At the utilization site a complementary device permits the separation of the DC power from the AC power and their reconstruction, for use in conventional AC-only and DC-only devices.

  7. ac-resistance-measuring instrument

    SciTech Connect

    Hof, P.J.

    1981-04-22

    An auto-ranging ac resistance measuring instrument for remote measurement of the resistance of an electrical device or circuit connected to the instrument includes a signal generator which generates an ac excitation signal for application to a load, including the device and the transmission line, a monitoring circuit which provides a digitally encoded signal representing the voltage across the load, and a microprocessor which operates under program control to provide an auto-ranging function by which range resistance is connected in circuit with the load to limit the load voltage to an acceptable range for the instrument, and an auto-compensating function by which compensating capacitance is connected in shunt with the range resistance to compensate for the effects of line capacitance.

  8. Substrate Controlled Divergence in Polyketide Synthase Catalysis

    PubMed Central

    2015-01-01

    Biochemical characterization of polyketide synthases (PKSs) has relied on synthetic substrates functionalized as electrophilic esters to acylate the enzyme and initiate the catalytic cycle. In these efforts, N-acetylcysteamine thioesters have typically been employed for in vitro studies of full PKS modules as well as excised domains. However, substrate engineering approaches to control the catalytic cycle of a full PKS module harboring multiple domains remain underexplored. This study examines a series of alternatively activated native hexaketide substrates on the catalytic outcome of PikAIV, the sixth and final module of the pikromycin (Pik) pathway. We demonstrate the ability to control product formation with greater than 10:1 selectivity for either full module catalysis, leading to a 14-membered macrolactone, or direct cyclization to a 12-membered ring. This outcome was achieved through modifying the type of hexaketide ester employed, demonstrating the utility of substrate engineering in PKS functional studies and biocatalysis. PMID:25730816

  9. Endothelial nitric oxide synthase in the microcirculation.

    PubMed

    Shu, Xiaohong; Keller, T C Stevenson; Begandt, Daniela; Butcher, Joshua T; Biwer, Lauren; Keller, Alexander S; Columbus, Linda; Isakson, Brant E

    2015-12-01

    Endothelial nitric oxide synthase (eNOS, NOS3) is responsible for producing nitric oxide (NO)--a key molecule that can directly (or indirectly) act as a vasodilator and anti-inflammatory mediator. In this review, we examine the structural effects of regulation of the eNOS enzyme, including post-translational modifications and subcellular localization. After production, NO diffuses to surrounding cells with a variety of effects. We focus on the physiological role of NO and NO-derived molecules, including microvascular effects on vessel tone and immune response. Regulation of eNOS and NO action is complicated; we address endogenous and exogenous mechanisms of NO regulation with a discussion of pharmacological agents used in clinical and laboratory settings and a proposed role for eNOS in circulating red blood cells. PMID:26390975

  10. SCAI/AATS/ACC/STS operator and institutional requirements for transcatheter valve repair and replacement, Part III: Pulmonic valve.

    PubMed

    Hijazi, Ziyad M; Ruiz, Carlos E; Zahn, Evan; Ringel, Richard; Aldea, Gabriel S; Bacha, Emile A; Bavaria, Joseph; Bolman, R Morton; Cameron, Duke E; Dean, Larry S; Feldman, Ted; Fullerton, David; Horlick, Eric; Mack, Michael J; Miller, D Craig; Moon, Marc R; Mukherjee, Debabrata; Trento, Alfredo; Tommaso, Carl L

    2015-07-01

    With the evolution of transcatheter valve replacement, an important opportunity has arisen for cardiologists and surgeons to collaborate in identifying the criteria for performing these procedures. Therefore, The Society for Cardiovascular Angiography and Interventions (SCAI), American Association for Thoracic Surgery (AATS), American College of Cardiology (ACC), and The Society of Thoracic Surgeons (STS) have partnered to provide recommendations for institutions to assess their potential for instituting and/or maintaining a transcatheter valve program. This article concerns transcatheter pulmonic valve replacement (tPVR). tPVR procedures are in their infancy with few reports available on which to base an expert consensus statement. Therefore, many of these recommendations are based on expert consensus and the few reports available. As the procedures evolve, technology advances, experience grows, and more data accumulate, there will certainly be a need to update this consensus statement. The writing committee and participating societies believe that the recommendations in this report serve as appropriate requisites. In some ways, these recommendations apply to institutions more than to individuals. There is a strong consensus that these new valve therapies are best performed using a Heart Team approach; thus, these credentialing criteria should be applied at the institutional level. Partnering societies used the ACC's policy on relationships with industry (RWI) and other entities to author this document (http://www.acc.org/guidelines/about-guidelines-and-clinical-documents). To avoid actual, potential, or perceived conflicts of interest due to industry relationships or personal interests, all members of the writing committee, as well as peer reviewers of the document, were asked to disclose all current healthcare-related relationships including those existing 12 months before the initiation of the writing effort. A committee of interventional cardiologists and

  11. Removal of Asbestos-Containing Coatings (ACC) from gas transmission pipelines. Final report, January 1991-October 1993

    SciTech Connect

    Petersen, L.E.; Blackburn, M.L.

    1994-01-01

    Corrosion control coatings on transmission pipelines may contain asbestos as a secondary component of the coating. Current environmental and health regulations require a wet removal process for asbestos materials that provides close control of airborne emissions and asbestos fibers in effluent water. Modification of current line-traveling, water jet equipment was successfully completed in developing an economic removal process for asbestos-containing coatings (ACC). Materials handling components were added in yard experiments that permitted water jet removal, slurry filtration, and residue containerization meeting emission control levels, while providing pipe cleanliness suitable for recoating. Field evaluations under in-the-ditch and over-the-ditch conditions on 16-, 26- and 30-inch pipelines verified the achievement of design coating removal rates and asbestos emission control that meets current regulations.

  12. Bacterial phytoene synthase: molecular cloning, expression, and characterization of Erwinia herbicola phytoene synthase.

    PubMed

    Iwata-Reuyl, Dirk; Math, Shivanand K; Desai, Shrivallabh B; Poulter, C Dale

    2003-03-25

    Phytoene synthase (PSase) catalyzes the condensation of two molecules of geranylgeranyl diphosphate (GGPP) to give prephytoene diphosphate (PPPP) and the subsequent rearrangement of the cyclopropylcarbinyl intermediate to phytoene. These reactions constitute the first pathway specific step in carotenoid biosynthesis. The crtB gene encoding phytoene synthase was isolated from a plasmid containing the carotenoid gene cluster in Erwinia herbicola and cloned into an Escherichia coli expression system. Upon induction, recombinant phytoene synthase constituted 5-10% of total soluble protein. To facilitate purification of the recombinant enzyme, the structural gene for PSase was modified by site-directed mutagenesis to incorporate a C-terminal Glu-Glu-Phe (EEF) tripepetide to allow purification by immunoaffinity chromatography on an immobilized monoclonal anti-alpha-tubulin antibody YL1/2 column. Purified recombinant PSase-EEF gave a band at 34.5 kDa upon SDS-PAGE. Recombinant PSase-EEF was then purified to >90% homogeneity in two steps by ion-exchange and immunoaffinity chromatography. The enzyme required Mn(2+) for activity, had a pH optimum of 8.2, and was strongly stimulated by detergent. The concentration of GGPP needed for half-maximal activity was approximately 35 microM, and a significant inhibition of activity was seen at GGPP concentrations above 100 microM. The sole product of the reaction was 15,15'-Z-phytoene. PMID:12641468

  13. CLYBL is a polymorphic human enzyme with malate synthase and β-methylmalate synthase activity

    PubMed Central

    Strittmatter, Laura; Li, Yang; Nakatsuka, Nathan J.; Calvo, Sarah E.; Grabarek, Zenon; Mootha, Vamsi K.

    2014-01-01

    CLYBL is a human mitochondrial enzyme of unknown function that is found in multiple eukaryotic taxa and conserved to bacteria. The protein is expressed in the mitochondria of all mammalian organs, with highest expression in brown fat and kidney. Approximately 5% of all humans harbor a premature stop polymorphism in CLYBL that has been associated with reduced levels of circulating vitamin B12. Using comparative genomics, we now show that CLYBL is strongly co-expressed with and co-evolved specifically with other components of the mitochondrial B12 pathway. We confirm that the premature stop polymorphism in CLYBL leads to a loss of protein expression. To elucidate the molecular function of CLYBL, we used comparative operon analysis, structural modeling and enzyme kinetics. We report that CLYBL encodes a malate/β-methylmalate synthase, converting glyoxylate and acetyl-CoA to malate, or glyoxylate and propionyl-CoA to β-methylmalate. Malate synthases are best known for their established role in the glyoxylate shunt of plants and lower organisms and are traditionally described as not occurring in humans. The broader role of a malate/β-methylmalate synthase in human physiology and its mechanistic link to vitamin B12 metabolism remain unknown. PMID:24334609

  14. Structure and Function of Fusicoccadiene Synthase, a Hexameric Bifunctional Diterpene Synthase.

    PubMed

    Chen, Mengbin; Chou, Wayne K W; Toyomasu, Tomonobu; Cane, David E; Christianson, David W

    2016-04-15

    Fusicoccin A is a diterpene glucoside phytotoxin generated by the fungal pathogen Phomopsis amygdali that causes the plant disease constriction canker, first discovered in New Jersey peach orchards in the 1930s. Fusicoccin A is also an emerging new lead in cancer chemotherapy. The hydrocarbon precursor of fusicoccin A is the tricyclic diterpene fusicoccadiene, which is generated by a bifunctional terpenoid synthase. Here, we report X-ray crystal structures of the individual catalytic domains of fusicoccadiene synthase: the C-terminal domain is a chain elongation enzyme that generates geranylgeranyl diphosphate, and the N-terminal domain catalyzes the cyclization of geranylgeranyl diphosphate to form fusicoccadiene. Crystal structures of each domain complexed with bisphosphonate substrate analogues suggest that three metal ions and three positively charged amino acid side chains trigger substrate ionization in each active site. While in vitro incubations reveal that the cyclase domain can utilize farnesyl diphosphate and geranyl diphosphate as surrogate substrates, these shorter isoprenoid diphosphates are mainly converted into acyclic alcohol or hydrocarbon products. Gel filtration chromatography and analytical ultracentrifugation experiments indicate that full-length fusicoccadiene synthase adopts hexameric quaternary structure, and small-angle X-ray scattering data yield a well-defined molecular envelope illustrating a plausible model for hexamer assembly. PMID:26734760

  15. Biosynthetic potential of sesquiterpene synthases: product profiles of Egyptian Henbane premnaspirodiene synthase and related mutants.

    PubMed

    Koo, Hyun Jo; Vickery, Christopher R; Xu, Yi; Louie, Gordon V; O'Maille, Paul E; Bowman, Marianne; Nartey, Charisse M; Burkart, Michael D; Noel, Joseph P

    2016-07-01

    The plant terpene synthase (TPS) family is responsible for the biosynthesis of a variety of terpenoid natural products possessing diverse biological functions. TPSs catalyze the ionization and, most commonly, rearrangement and cyclization of prenyl diphosphate substrates, forming linear and cyclic hydrocarbons. Moreover, a single TPS often produces several minor products in addition to a dominant product. We characterized the catalytic profiles of Hyoscyamus muticus premnaspirodiene synthase (HPS) and compared it with the profile of a closely related TPS, Nicotiana tabacum 5-epi-aristolochene synthase (TEAS). The profiles of two previously studied HPS and TEAS mutants, each containing nine interconverting mutations, dubbed HPS-M9 and TEAS-M9, were also characterized. All four TPSs were compared under varying temperature and pH conditions. In addition, we solved the X-ray crystal structures of TEAS and a TEAS quadruple mutant complexed with substrate and products to gain insight into the enzymatic features modulating product formation. These informative structures, along with product profiles, provide new insight into plant TPS catalytic promiscuity. PMID:27328867

  16. 2015 ACC Health Policy Statement on Cardiovascular Team-Based Care and the Role of Advanced Practice Providers.

    PubMed

    Brush, John E; Handberg, Eileen M; Biga, Cathleen; Birtcher, Kim K; Bove, Alfred A; Casale, Paul N; Clark, Michael G; Garson, Arthur; Hines, Jerome L; Linderbaum, Jane A; Rodgers, George P; Shor, Robert A; Thourani, Vinod H; Wyman, Janet F

    2015-05-19

    The mission of the American College of Cardiology is "to transform cardiovascular care and improve heart health." Cardiovascular team-based care is a paradigm for practice that can transform care, improve heart health, and help meet the demands of the future. One strategic goal of the College is to help members successfully transition their clinical practices to the future, with all its complexity, challenges, and opportunities. The ACC's strategic plan is aligned with the triple aim of improved care, improved population health, and lower costs per capita. The traditional understanding of quality, access, and cost is that you cannot improve one component without diminishing the others. With cardiovascular team-based care, it is possible to achieve the triple aim of improving quality, access, and cost simultaneously to also improve cardiovascular health. Striving to serve the best interests of patients is the true north of our guiding principles. Cardiovascular team-based care is a model that can improve care coordination and communication and allow each team member to focus more on the quality of care. In addition, the cardiovascular team-based care model increases access to cardiovascular care and allows expansion of services to populations and geographic areas that are currently underserved. This document will increase awareness of the important components of cardiovascular team-based care and create an opportunity for more discussion about the most creative and effective means of implementing it. We hope that this document will stimulate further discussions and activities within the ACC and beyond about team-based care. We have identified areas that need improvement, specifically in APP education and state regulation. The document encourages the exploration of collaborative care models that should enable team members to optimize their education, training, experience, and talent. Improved team leadership, coordination, collaboration, engagement, and efficiency

  17. PKMiner: a database for exploring type II polyketide synthases

    PubMed Central

    2012-01-01

    Background Bacterial aromatic polyketides are a pharmacologically important group of natural products synthesized by type II polyketide synthases (type II PKSs) in actinobacteria. Isolation of novel aromatic polyketides from microbial sources is currently impeded because of the lack of knowledge about prolific taxa for polyketide synthesis and the difficulties in finding and optimizing target microorganisms. Comprehensive analysis of type II PKSs and the prediction of possible polyketide chemotypes in various actinobacterial genomes will thus enable the discovery or synthesis of novel polyketides in the most plausible microorganisms. Description We performed a comprehensive computational analysis of type II PKSs and their gene clusters in actinobacterial genomes. By identifying type II PKS subclasses from the sequence analysis of 280 known type II PKSs, we developed highly accurate domain classifiers for these subclasses and derived prediction rules for aromatic polyketide chemotypes generated by different combinations of type II PKS domains. Using 319 available actinobacterial genomes, we predicted 231 type II PKSs from 40 PKS gene clusters in 25 actinobacterial genomes, and polyketide chemotypes corresponding to 22 novel PKS gene clusters in 16 genomes. These results showed that the microorganisms capable of producing aromatic polyketides are specifically distributed within a certain suborder of Actinomycetales such as Catenulisporineae, Frankineae, Micrococcineae, Micromonosporineae, Pseudonocardineae, Streptomycineae, and Streptosporangineae. Conclusions We could identify the novel candidates of type II PKS gene clusters and their polyketide chemotypes in actinobacterial genomes by comprehensive analysis of type II PKSs and prediction of aromatic polyketides. The genome analysis results indicated that the specific suborders in actinomycetes could be used as prolific taxa for polyketide synthesis. The chemotype-prediction rules with the suggested type II PKS

  18. Cellulose in Cyanobacteria. Origin of Vascular Plant Cellulose Synthase?

    PubMed Central

    Nobles, David R.; Romanovicz, Dwight K.; Brown, R. Malcolm

    2001-01-01

    Although cellulose biosynthesis among the cyanobacteria has been suggested previously, we present the first conclusive evidence, to our knowledge, of the presence of cellulose in these organisms. Based on the results of x-ray diffraction, electron microscopy of microfibrils, and cellobiohydrolase I-gold labeling, we report the occurrence of cellulose biosynthesis in nine species representing three of the five sections of cyanobacteria. Sequence analysis of the genomes of four cyanobacteria revealed the presence of multiple amino acid sequences bearing the DDD35QXXRW motif conserved in all cellulose synthases. Pairwise alignments demonstrated that CesAs from plants were more similar to putative cellulose synthases from Anabaena sp. Pasteur Culture Collection 7120 and Nostoc punctiforme American Type Culture Collection 29133 than any other cellulose synthases in the database. Multiple alignments of putative cellulose synthases from Anabaena sp. Pasteur Culture Collection 7120 and N. punctiforme American Type Culture Collection 29133 with the cellulose synthases of other prokaryotes, Arabidopsis, Gossypium hirsutum, Populus alba × Populus tremula, corn (Zea mays), and Dictyostelium discoideum showed that cyanobacteria share an insertion between conserved regions U1 and U2 found previously only in eukaryotic sequences. Furthermore, phylogenetic analysis indicates that the cyanobacterial cellulose synthases share a common branch with CesAs of vascular plants in a manner similar to the relationship observed with cyanobacterial and chloroplast 16s rRNAs, implying endosymbiotic transfer of CesA from cyanobacteria to plants and an ancient origin for cellulose synthase in eukaryotes. PMID:11598227

  19. Class IV polyhydroxyalkanoate (PHA) synthases and PHA-producing Bacillus.

    PubMed

    Tsuge, Takeharu; Hyakutake, Manami; Mizuno, Kouhei

    2015-08-01

    This review highlights the recent investigations of class IV polyhydroxyalkanoate (PHA) synthases, the newest classification of PHA synthases. Class IV synthases are prevalent in organisms of the Bacillus genus and are composed of a catalytic subunit PhaC (approximately 40 kDa), which has a PhaC box sequence ([GS]-X-C-X-[GA]-G) at the active site, and a second subunit PhaR (approximately 20 kDa). The representative PHA-producing Bacillus strains are Bacillus megaterium and Bacillus cereus; the nucleotide sequence of phaC and the genetic organization of the PHA biosynthesis gene locus are somewhat different between these two strains. It is generally considered that class IV synthases favor short-chain-length monomers such as 3-hydroxybutyrate (C4) and 3-hydroxyvalerate (C5) for polymerization, but can polymerize some unusual monomers as minor components. In Escherichia coli expressing PhaRC from B. cereus YB-4, the biosynthesized PHA undergoes synthase-catalyzed alcoholytic cleavage using endogenous and exogenous alcohols. This alcoholysis is thought to be shared among class IV synthases, and this reaction is useful not only for the regulation of PHA molecular weight but also for the modification of the PHA carboxy terminus. The novel properties of class IV synthases will open up the possibility for the design of new PHA materials. PMID:26135986

  20. Acetolactate Synthase Activity in Developing Maize (Zea mays L.) Kernels

    PubMed Central

    Muhitch, Michael J.

    1988-01-01

    Acetolactate synthase (EC 4.1.3.18) activity was examined in maize (Zea mays L.) endosperm and embryos as a function of kernel development. When assayed using unpurified homogenates, embryo acetolactate synthase activity appeared less sensitive to inhibition by leucine + valine and by the imidazolinone herbicide imazapyr than endosperm acetolactate synthase activity. Evidence is presented to show that pyruvate decarboxylase contributes to apparent acetolactate synthase activity in crude embryo extracts and a modification of the acetolactate synthase assay is proposed to correct for the presence of pyruvate decarboxylase in unpurified plant homogenates. Endosperm acetolactate synthase activity increased rapidly during early kernel development, reaching a maximum of 3 micromoles acetoin per hour per endosperm at 25 days after pollination. In contrast, embryo activity was low in young kernels and steadily increased throughout development to a maximum activity of 0.24 micromole per hour per embryo by 45 days after pollination. The sensitivity of both endosperm and embryo acetolactate synthase activities to feedback inhibition by leucine + valine did not change during kernel development. The results are compared to those found for other enzymes of nitrogen metabolism and discussed with respect to the potential roles of the embryo and endosperm in providing amino acids for storage protein synthesis. PMID:16665871

  1. Expression, purification and activity assay of a patchoulol synthase cDNA variant fused to thioredoxin in Escherichia coli.

    PubMed

    Hartwig, S; Frister, T; Alemdar, S; Li, Z; Krings, U; Berger, R G; Scheper, T; Beutel, S

    2014-05-01

    Probing a cDNA library extracted from Pogostemon cablin (Indian Patchouli) with gene specific primers, a variant of patchoulol synthase PTS (GenBank acc. No.: AY508730) was amplified, cloned, and sequenced. The amino acid sequence deduced from the cloned cDNA exhibited a sequence variation of 3.4% compared to the annotated sequence. The enzyme variant tended to form inclusion bodies when expressed in Escherichia coli. The coding sequence was fused to the T7-tag, His-tag and to thioredoxin. Constructs were expressed in three different E. coli expression strains, with several strain/construct combinations yielding soluble enzyme. By fusion to thioredoxin and careful codon optimization of the eukaryotic sequence, soluble expression could be improved on average by 42% in comparison to an unoptimized, His-tagged construct. The thioredoxin-fused protein was successfully purified using a one-step Co(2+)-IMAC purification procedure. Bioactivity assays using prepared farnesyl diphosphate (FDP) in milliliter-scale batch reactions, showed activity of the fused enzyme even with thioredoxin attached. The product spectrum of the enzyme was compared to patchouli oil standards by GC-MS and the main products were identified. Interestingly, the variant showed a shift in product spectrum with germacrene A being the most abundant product instead of patchouli alcohol. In silico structural modeling shows a possible chemical and structural change in the active site of the enzyme, which might be responsible for the shift in product composition. PMID:24576659

  2. Xenon in And at the End of the Tunnel of Bifunctional Carbon Monoxide Dehydrogenase/Acetyl-CoA Synthase

    SciTech Connect

    Doukov, T.I.; Blasiak, L.C.; Seravalli, J.; Ragsdale, S.W.; Drennan, C.L.; /MIT /SLAC, SSRL /Nebraska U.

    2009-05-11

    A fascinating feature of some bifunctional enzymes is the presence of an internal channel or tunnel to connect the multiple active sites. A channel can allow for a reaction intermediate generated at one active site to be used as a substrate at a second active site, without the need for the intermediate to leave the safety of the protein matrix. One such bifunctional enzyme is carbon monoxide dehydrogenase/acetyl-CoA synthase from Moorella thermoacetica (mtCODH/ACS). A key player in the global carbon cycle, CODH/ACS uses a Ni-Fe-S center called the C-cluster to reduce carbon dioxide to carbon monoxide and uses a second Ni-Fe-S center, called the A-cluster, to assemble acetyl-CoA from a methyl group, coenzyme A, and C-cluster-generated CO. mtCODH/ACS has been proposed to contain one of the longest enzyme channels (138 A long) to allow for intermolecular CO transport. Here, we report a 2.5 A resolution structure of xenon-pressurized mtCODH/ACS and examine the nature of gaseous cavities within this enzyme. We find that the cavity calculation program CAVENV accurately predicts the channels connecting the C- and A-clusters, with 17 of 19 xenon binding sites within the predicted regions. Using this X-ray data, we analyze the amino acid composition surrounding the 19 Xe sites and consider how the protein fold is utilized to carve out such an impressive interior passageway. Finally, structural comparisons of Xe-pressurized mtCODH/ACS with related enzyme structures allow us to study channel design principles, as well as consider the conformational flexibility of an enzyme that contains a cavity through its center.

  3. Parasite Killing in Malaria Non-Vector Mosquito Anopheles culicifacies Species B: Implication of Nitric Oxide Synthase Upregulation

    PubMed Central

    Vijay, Sonam; Rawat, Manmeet; Adak, Tridibes; Dixit, Rajnikant; Nanda, Nutan; Srivastava, Harish; Sharma, Joginder K.; Prasad, Godavarthi B. K. S.; Sharma, Arun

    2011-01-01

    Background Anopheles culicifacies, the main vector of human malaria in rural India, is a complex of five sibling species. Despite being phylogenetically related, a naturally selected subgroup species B of this sibling species complex is found to be a poor vector of malaria. We have attempted to understand the differences between vector and non-vector Anopheles culicifacies mosquitoes in terms of transcriptionally activated nitric oxide synthase (AcNOS) physiologies to elucidate the mechanism of refractoriness. Identification of the differences between genes and gene products that may impart refractory phenotype can facilitate development of novel malaria transmission blocking strategies. Methodology/Principal Findings We conducted a study on phylogenetically related susceptible (species A) and refractory (species B) sibling species of An. culicifacies mosquitoes to characterize biochemical and molecular differences in AcNOS gene and gene elements and their ability to inhibit oocyst growth. We demonstrate that in species B, AcNOS specific activity and nitrite/nitrates in mid-guts and haemolymph were higher as compared to species A after invasion of the mid-gut by P. vivax at the beginning and during the course of blood feeding. Semiquantitative RT-PCR and real time PCR data of AcNOS concluded that this gene is more abundantly expressed in midgut of species B than in species A and is transcriptionally upregulated post blood meals. Dietary feeding of L-NAME along with blood meals significantly inhibited midgut AcNOS activity leading to an increase in oocyst production in An. culicifacies species B. Conclusions/Significance We hypothesize that upregulation of mosquito innate cytotoxicity due to NOS in refractory strain to Plasmodium vivax infection may contribute to natural refractoriness in An. culicifacies mosquito population. This innate capacity of refractory mosquitoes could represent the ancestral function of the mosquito immune system against the parasite and

  4. Generation and Functional Evaluation of Designer Monoterpene Synthases.

    PubMed

    Srividya, N; Lange, I; Lange, B M

    2016-01-01

    Monoterpene synthases are highly versatile enzymes that catalyze the first committed step in the pathways toward terpenoids, the structurally most diverse class of plant natural products. Recent advancements in our understanding of the reaction mechanism have enabled engineering approaches to develop mutant monoterpene synthases that produce specific monoterpenes. In this chapter, we are describing protocols to introduce targeted mutations, express mutant enzyme catalysts in heterologous hosts, and assess their catalytic properties. Mutant monoterpene synthases have the potential to contribute significantly to synthetic biology efforts aimed at producing larger amounts of commercially attractive monoterpenes. PMID:27480686

  5. The Pseudouridine Synthases Proceed through a Glycal Intermediate

    PubMed Central

    2016-01-01

    The pseudouridine synthases isomerize (U) in RNA to pseudouridine (Ψ), and the mechanism that they follow has long been a question of interest. The recent elucidation of a product of the mechanistic probe 5-fluorouridine that had been epimerized to the arabino isomer suggested that the Ψ synthases might operate through a glycal intermediate formed by deprotonation of C2′. When that position in substrate U is deuterated, a primary kinetic isotope effect is observed, which indisputably indicates that the proposed deprotonation occurs during the isomerization of U to Ψ and establishes the mechanism followed by the Ψ synthases. PMID:27292228

  6. Computational design and selections for an engineered, thermostable terpene synthase

    PubMed Central

    Diaz, Juan E; Lin, Chun-Shi; Kunishiro, Kazuyoshi; Feld, Birte K; Avrantinis, Sara K; Bronson, Jonathan; Greaves, John; Saven, Jeffery G; Weiss, Gregory A

    2011-01-01

    Terpenoids include structurally diverse antibiotics, flavorings, and fragrances. Engineering terpene synthases for control over the synthesis of such compounds represents a long sought goal. We report computational design, selections, and assays of a thermostable mutant of tobacco 5-epi-aristolochene synthase (TEAS) for the catalysis of carbocation cyclization reactions at elevated temperatures. Selection for thermostability included proteolytic digestion followed by capture of intact proteins. Unlike the wild-type enzyme, the mutant TEAS retains enzymatic activity at 65°C. The thermostable terpene synthase variant denatures above 80°C, approximately twice the temperature of the wild-type enzyme. PMID:21739507

  7. The Pseudouridine Synthases Proceed through a Glycal Intermediate.

    PubMed

    Veerareddygari, Govardhan Reddy; Singh, Sanjay K; Mueller, Eugene G

    2016-06-29

    The pseudouridine synthases isomerize (U) in RNA to pseudouridine (Ψ), and the mechanism that they follow has long been a question of interest. The recent elucidation of a product of the mechanistic probe 5-fluorouridine that had been epimerized to the arabino isomer suggested that the Ψ synthases might operate through a glycal intermediate formed by deprotonation of C2'. When that position in substrate U is deuterated, a primary kinetic isotope effect is observed, which indisputably indicates that the proposed deprotonation occurs during the isomerization of U to Ψ and establishes the mechanism followed by the Ψ synthases. PMID:27292228

  8. Geranylfarnesyl diphosphate synthase from Methanosarcina mazei: Different role, different evolution

    SciTech Connect

    Ogawa, Takuya; Yoshimura, Tohru; Hemmi, Hisashi

    2010-02-26

    The gene of (all-E) geranylfarnesyl diphosphate synthase that is responsible for the biosynthesis of methanophenazine, an electron carrier utilized for methanogenesis, was cloned from a methanogenic archaeon Methanosarcina mazei Goe1. The properties of the recombinant enzyme and the results of phylogenetic analysis suggest that the enzyme is closely related to (all-E) prenyl diphosphate synthases that are responsible for the biosynthesis of respiratory quinones, rather than to the enzymes involved in the biosynthesis of archaeal membrane lipids, including (all-E) geranylfarnesyl diphosphate synthase from a thermophilic archaeon.

  9. Differential Expression of 1-Aminocyclopropane-1-Carboxylate Synthase Genes during Orchid Flower Senescence Induced by the Protein Phosphatase Inhibitor Okadaic Acid1

    PubMed Central

    Wang, Ning Ning; Yang, Shang Fa; Charng, Yee-yung

    2001-01-01

    Applying 10 pmol of okadaic acid (OA), a specific inhibitor of type 1 or type 2A serine/threonine protein phosphatases, to the orchid (Phalaenopsis species) stigma induced a dramatic increase in ethylene production and an accelerated senescence of the whole flower. Aminoethoxyvinylglycine or silver thiosulfate, inhibitors of ethylene biosynthesis or action, respectively, effectively inhibited the OA-induced ethylene production and retarded flower senescence, suggesting that the protein phosphatase inhibitor induced orchid flower senescence through an ethylene-mediated signaling pathway. OA treatment induced a differential expression pattern for the 1-aminocyclopropane-1-carboxylic acid synthase multigene family. Accumulation of Phal-ACS1 transcript in the stigma, labelum, and ovary induced by OA were higher than those induced by pollination as determined by “semiquantitative” reverse transcriptase-polymerase chain reaction. In contrast, the transcript levels of Phal-ACS2 and Phal-ACS3 induced by OA were much lower than those induced by pollination. Staurosporine, a protein kinase inhibitor, on the other hand, inhibited the OA-induced Phal-ACS1 expression in the stigma and delayed flower senescence. Our results suggest that a hyper-phosphorylation status of an unidentified protein(s) is involved in up-regulating the expression of Phal-ACS1 gene resulting in increased ethylene production and accelerated the senescence process of orchid flower. PMID:11351088

  10. The glossyhead1 Allele of ACC1 Reveals a Principal Role for Multidomain Acetyl-Coenzyme A Carboxylase in the Biosynthesis of Cuticular Waxes by Arabidopsis

    SciTech Connect

    Lu, S.; Xu, C.; Zhao, H.; Parsons, E. P.; Kosma, D. K.; Xu, X.; Chao, D.; Lohrey, G.; Bangarusamy, D. K.; Wang, G.; Bressan, R. A.; Jenks, M. A.

    2011-11-01

    A novel mutant of Arabidopsis (Arabidopsis thaliana), having highly glossy inflorescence stems, postgenital fusion in floral organs, and reduced fertility, was isolated from an ethyl methanesulfonate-mutagenized population and designated glossyhead1 (gsd1). The gsd1 locus was mapped to chromosome 1, and the causal gene was identified as a new allele of Acetyl-Coenzyme A Carboxylase1 (ACC1), a gene encoding the main enzyme in cytosolic malonyl-coenzyme A synthesis. This, to our knowledge, is the first mutant allele of ACC1 that does not cause lethality at the seed or early germination stage, allowing for the first time a detailed analysis of ACC1 function in mature tissues. Broad lipid profiling of mature gsd1 organs revealed a primary role for ACC1 in the biosynthesis of the very-long-chain fatty acids (C{sub 20:0} or longer) associated with cuticular waxes and triacylglycerols. Unexpectedly, transcriptome analysis revealed that gsd1 has limited impact on any lipid metabolic networks but instead has a large effect on environmental stress-responsive pathways, especially senescence and ethylene synthesis determinants, indicating a possible role for the cytosolic malonyl-coenzyme A-derived lipids in stress response signaling.

  11. Transformation of Brassica napus canola cultivars with Arabidopsis thaliana acetohydroxyacid synthase genes and analysis of herbicide resistance.

    PubMed

    Miki, B L; Labbé, H; Hattori, J; Ouellet, T; Gabard, J; Sunohara, G; Charest, P J; Iyer, V N

    1990-10-01

    A survey of selected crop species and weeds was conducted to evaluate the inhibition of the enzyme acetohydroxyacid synthase (AHAS) and seedling growth in vitro by the sulfonylurea herbicides chlorsulfuron, DPX A7881, DPX L5300, DPX M6316 and the imidazolinone herbicides AC243,997, AC263,499, AC252,214. Particular attention was given to the Brassica species including canola cultivars and cruciferous weeds such as B. kaber (wild mustard) and Thlaspi arvense (stinkweed). Transgenic lines of B. napus cultivars Westar and Profit, which express the Arabidopsis thaliana wild-type AHAS gene or the mutant gene csr1-1 at levels similar to the resident AHAS genes, were generated and compared. The mutant gene was essential for resistance to the sulfonylurea chlorsulfuron but not to DPX A7881, which appeared to be tolerated by certain Brassica species. Cross-resistance to the imidazolinones did not occur. The level of resistance to chlorsulfuron in transgenic canola greatly exceeded the levels that were toxic to the Brassica species or cruciferous weeds. Direct selection of transgenic lines with chlorsulfuron sprayed at field levels under greenhouse conditions was achieved. PMID:24221001

  12. Dimer ribbons of ATP synthase shape the inner mitochondrial membrane

    PubMed Central

    Strauss, Mike; Hofhaus, Götz; Schröder, Rasmus R; Kühlbrandt, Werner

    2008-01-01

    ATP synthase converts the electrochemical potential at the inner mitochondrial membrane into chemical energy, producing the ATP that powers the cell. Using electron cryo-tomography we show that the ATP synthase of mammalian mitochondria is arranged in long ∼1-μm rows of dimeric supercomplexes, located at the apex of cristae membranes. The dimer ribbons enforce a strong local curvature on the membrane with a 17-nm outer radius. Calculations of the electrostatic field strength indicate a significant increase in charge density, and thus in the local pH gradient of ∼0.5 units in regions of high membrane curvature. We conclude that the mitochondrial cristae act as proton traps, and that the proton sink of the ATP synthase at the apex of the compartment favours effective ATP synthesis under proton-limited conditions. We propose that the mitochondrial ATP synthase organises itself into dimer ribbons to optimise its own performance. PMID:18323778

  13. Thymoquinone Inhibits Escherichia coli ATP Synthase and Cell Growth

    PubMed Central

    Ahmad, Zulfiqar; Laughlin, Thomas F.; Kady, Ismail O.

    2015-01-01

    We examined the thymoquinone induced inhibition of purified F1 or membrane bound F1FO E. coli ATP synthase. Both purified F1 and membrane bound F1FO were completely inhibited by thymoquinone with no residual ATPase activity. The process of inhibition was fully reversible and identical in both membrane bound F1Fo and purified F1 preparations. Moreover, thymoquinone induced inhibition of ATP synthase expressing wild-type E. coli cell growth and non-inhibition of ATPase gene deleted null control cells demonstrates that ATP synthase is a molecular target for thymoquinone. This also links the beneficial dietary based antimicrobial and anticancer effects of thymoquinone to its inhibitory action on ATP synthase. PMID:25996607

  14. Possible Role of 1-Aminocyclopropane-1-Carboxylate (ACC) Deaminase Activity of Sinorhizobium sp. BL3 on Symbiosis with Mung Bean and Determinate Nodule Senescence

    PubMed Central

    Tittabutr, Panlada; Sripakdi, Sudarat; Boonkerd, Nantakorn; Tanthanuch, Waraporn; Minamisawa, Kiwamu; Teaumroong, Neung

    2015-01-01

    Sinorhizobium sp. BL3 forms symbiotic interactions with mung bean (Vigna radiata) and contains lrpL-acdS genes, which encode the 1-aminocyclopropane-1-carboxylate (ACC) deaminase enzyme that cleaves ACC, a precursor of plant ethylene synthesis. Since ethylene interferes with nodule formation in some legumes and plays a role in senescence in plant cells, BL3-enhancing ACC deaminase activity (BL3+) and defective mutant (BL3−) strains were constructed in order to investigate the effects of this enzyme on symbiosis and nodule senescence. Nodulation competitiveness was weaker in BL3− than in the wild-type, but was stronger in BL3+. The inoculation of BL3− into mung bean resulted in less plant growth, a lower nodule dry weight, and smaller nodule number than those in the wild-type, whereas the inoculation of BL3+ had no marked effects. However, similar nitrogenase activity was observed with all treatments; it was strongly detected 3 weeks after the inoculation and gradually declined with time, indicating senescence. The rate of plant nodulation by BL3+ increased in a time-dependent manner. Nodules occupied by BL3− formed smaller symbiosomes, and bacteroid degradation was more prominent than that in the wild-type 7 weeks after the inoculation. Changes in biochemical molecules during nodulation were tracked by Fourier Transform Infrared (FT-IR) microspectroscopy, and the results obtained confirmed that aging processes differed in nodules occupied by BL3 and BL3−. This is the first study to show the possible role of ACC deaminase activity in senescence in determinate nodules. Our results suggest that an increase in ACC deaminase activity in this strain does not extend the lifespan of nodules, whereas the lack of this activity may accelerate nodule senescence. PMID:26657304

  15. Ac electrode diagnostics in ac-operated metal halide lamps

    NASA Astrophysics Data System (ADS)

    Luijks, G. M. J. F.; van Esveld, H. A.; Nijdam, S.; Weerdesteijn, P. A. M.

    2008-07-01

    A diagnostic technique is presented to determine the electrode work function in ac-operated metal halide lamps. The heart of the experimental set-up is a high-speed photodiode array detector, which is able to follow real-time variations of electrode tip temperature and near-electrode plasma emissions in ac-operated experimental YAG lamps, enabling discrimination between the anode and cathode effects. Electrode tip temperature ripples have been measured for 100 Hz square wave operation and simulated with an existing electrode model. By using the electrode work function as main fit parameter for the simulations it is found that the measured cooling effect of the electrode tip in a NaTlDy-iodide lamp is caused by a gas-phase emitter effect of Dy. It is concluded that Dy coverage of the electrode tip causes an effective work function reduction of 0.3 eV at 100 Hz square wave operation, considerably less than the 1.0 eV reduction measured earlier for dc operation.

  16. Biosynthesis of riboflavin: an unusual riboflavin synthase of Methanobacterium thermoautotrophicum.

    PubMed Central

    Eberhardt, S; Korn, S; Lottspeich, F; Bacher, A

    1997-01-01

    Riboflavin synthase was purified by a factor of about 1,500 from cell extract of Methanobacterium thermoautotrophicum. The enzyme had a specific activity of about 2,700 nmol mg(-1) h(-1) at 65 degrees C, which is relatively low compared to those of riboflavin synthases of eubacteria and yeast. Amino acid sequences obtained after proteolytic cleavage had no similarity with known riboflavin synthases. The gene coding for riboflavin synthase (designated ribC) was subsequently cloned by marker rescue with a ribC mutant of Escherichia coli. The ribC gene of M. thermoautotrophicum specifies a protein of 153 amino acid residues. The predicted amino acid sequence agrees with the information gleaned from Edman degradation of the isolated protein and shows 67% identity with the sequence predicted for the unannotated reading frame MJ1184 of Methanococcus jannaschii. The ribC gene is adjacent to a cluster of four genes with similarity to the genes cbiMNQO of Salmonella typhimurium, which form part of the cob operon (this operon contains most of the genes involved in the biosynthesis of vitamin B12). The amino acid sequence predicted by the ribC gene of M. thermoautotrophicum shows no similarity whatsoever to the sequences of riboflavin synthases of eubacteria and yeast. Most notably, the M. thermoautotrophicum protein does not show the internal sequence homology characteristic of eubacterial and yeast riboflavin synthases. The protein of M. thermoautotrophicum can be expressed efficiently in a recombinant E. coli strain. The specific activity of the purified, recombinant protein is 1,900 nmol mg(-1) h(-1) at 65 degrees C. In contrast to riboflavin synthases from eubacteria and fungi, the methanobacterial enzyme has an absolute requirement for magnesium ions. The 5' phosphate of 6,7-dimethyl-8-ribityllumazine does not act as a substrate. The findings suggest that riboflavin synthase has evolved independently in eubacteria and methanobacteria. PMID:9139911

  17. The AC photovoltaic module is here!

    NASA Astrophysics Data System (ADS)

    Strong, Steven J.; Wohlgemuth, John H.; Wills, Robert H.

    1997-02-01

    This paper describes the design, development, and performance results of a large-area photovoltaic module whose electrical output is ac power suitable for direct connection to the utility grid. The large-area ac PV module features a dedicated, integrally mounted, high-efficiency dc-to-ac power inverter with a nominal output of 250 watts (STC) at 120 Vac, 60 H, that is fully compatible with utility power. The module's output is connected directly to the building's conventional ac distribution system without need for any dc wiring, string combiners, dc ground-fault protection or additional power-conditioning equipment. With its advantages, the ac photovoltaic module promises to become a universal building block for use in all utility-interactive PV systems. This paper discusses AC Module design aspects and utility interface issues (including islanding).

  18. Nitric oxide synthase in ferret brain: localization and characterization.

    PubMed Central

    Matsumoto, T.; Mitchell, J. A.; Schmidt, H. H.; Kohlhaas, K. L.; Warner, T. D.; Förstermann, U.; Murad, F.

    1992-01-01

    1. In the present study, we have investigated the distribution of nitric oxide synthase in the ferret brain. Nitric oxide synthase was determined biochemically and immunochemically. 2. In the rat brain, the highest nitric oxide synthase activity has been detected in the cerebellum. However, in the ferret brain, the highest activity was found in the striatum and the lowest in the cerebellum and cerebral cortex. The enzymatic activity was localized predominantly in the cytosolic fractions, it was dependent on NADPH and Ca2+, and inhibited by NG-nitro-L-arginine or NG-methyl-L-arginine. 3. Western blot analysis revealed that all regions of the ferret brain contained a 160 kD protein crossreacting with an antibody to nitric oxide synthase purified from the rat cerebellum, and the levels of relative intensity of staining by the antibody correlated with the distribution of nitric oxide synthase activity. 4. These results indicate that the ferret brain contains a nitric oxide synthase similar to the rat brain, but the distribution of enzymatic activity in the ferret brain differs markedly from the rat brain. Images Figure 1 PMID:1282076

  19. Understanding structure, function, and mutations in the mitochondrial ATP synthase

    PubMed Central

    Xu, Ting; Pagadala, Vijayakanth; Mueller, David M.

    2015-01-01

    The mitochondrial ATP synthase is a multimeric enzyme complex with an overall molecular weight of about 600,000 Da. The ATP synthase is a molecular motor composed of two separable parts: F1 and Fo. The F1 portion contains the catalytic sites for ATP synthesis and protrudes into the mitochondrial matrix. Fo forms a proton turbine that is embedded in the inner membrane and connected to the rotor of F1. The flux of protons flowing down a potential gradient powers the rotation of the rotor driving the synthesis of ATP. Thus, the flow of protons though Fo is coupled to the synthesis of ATP. This review will discuss the structure/function relationship in the ATP synthase as determined by biochemical, crystallographic, and genetic studies. An emphasis will be placed on linking the structure/function relationship with understanding how disease causing mutations or putative single nucleotide polymorphisms (SNPs) in genes encoding the subunits of the ATP synthase, will affect the function of the enzyme and the health of the individual. The review will start by summarizing the current understanding of the subunit composition of the enzyme and the role of the subunits followed by a discussion on known mutations and their effect on the activity of the ATP synthase. The review will conclude with a summary of mutations in genes encoding subunits of the ATP synthase that are known to be responsible for human disease, and a brief discussion on SNPs. PMID:25938092

  20. Glutathione Regulates 1-Aminocyclopropane-1-Carboxylate Synthase Transcription via WRKY33 and 1-Aminocyclopropane-1-Carboxylate Oxidase by Modulating Messenger RNA Stability to Induce Ethylene Synthesis during Stress.

    PubMed

    Datta, Riddhi; Kumar, Deepak; Sultana, Asma; Hazra, Saptarshi; Bhattacharyya, Dipto; Chattopadhyay, Sharmila

    2015-12-01

    Glutathione (GSH) plays a fundamental role in plant defense-signaling network. Recently, we have established the involvement of GSH with ethylene (ET) to combat environmental stress. However, the mechanism of GSH-ET interplay still remains unexplored. Here, we demonstrate that GSH induces ET biosynthesis by modulating the transcriptional and posttranscriptional regulations of its key enzymes, 1-aminocyclopropane-1-carboxylate synthase (ACS) and 1-aminocyclopropane-1-carboxylate oxidase (ACO). Transgenic Arabidopsis (Arabidopsis thaliana) plants with enhanced GSH content (AtECS) exhibited remarkable up-regulation of ACS2, ACS6, and ACO1 at transcript as well as protein levels, while they were down-regulated in the GSH-depleted phytoalexin deficient2-1 (pad2-1) mutant. We further observed that GSH induced ACS2 and ACS6 transcription in a WRKY33-dependent manner, while ACO1 transcription remained unaffected. On the other hand, the messenger RNA stability for ACO1 was found to be increased by GSH, which explains our above observations. In addition, we also identified the ACO1 protein to be a subject for S-glutathionylation, which is consistent with our in silico data. However, S-glutathionylation of ACS2 and ACS6 proteins was not detected. Further, the AtECS plants exhibited resistance to necrotrophic infection and salt stress, while the pad2-1 mutant was sensitive. Exogenously applied GSH could improve stress tolerance in wild-type plants but not in the ET-signaling mutant ethylene insensitive2-1, indicating that GSH-mediated resistance to these stresses occurs via an ET-mediated pathway. Together, our investigation reveals a dual-level regulation of ET biosynthesis by GSH during stress. PMID:26463088

  1. Protein preparation, crystallization and preliminary X-ray analysis of Polygonum cuspidatum bifunctional chalcone synthase/benzalacetone synthase.

    PubMed

    Lu, Heshu; Yang, Mingfeng; Liu, Chunmei; Lu, Ping; Cang, Huaixing; Ma, Lanqing

    2013-08-01

    The chalcone synthase (CHS) superfamily of type III polyketide synthases (PKSs) generate the backbones of a variety of plant secondary metabolites. An active bifunctional chalcone synthase/benzalacetone synthase (CHS/BAS) from Polygonum cuspidatum was overexpressed in Escherichia coli as a C-terminally polyhistidine-tagged fusion protein, purified to homogeneity and crystallized using polyethylene glycol 4000 as a precipitant. The production of well shaped crystals of the complex between PcPKS1 and benzalacetone was dependent on the presence of sorbitol and barium chloride as additives. The crystals belonged to the orthorhombic space group P2₁2₁2₁, with unit-cell parameters a = 80.23, b = 81.01, c = 122.89 Å, and diffracted X-rays to at least 2.0 Å resolution. PMID:23908031

  2. Nitric Oxide Synthases in Heart Failure

    PubMed Central

    Carnicer, Ricardo; Crabtree, Mark J.; Sivakumaran, Vidhya

    2013-01-01

    Abstract Significance: The regulation of myocardial function by constitutive nitric oxide synthases (NOS) is important for the maintenance of myocardial Ca2+ homeostasis, relaxation and distensibility, and protection from arrhythmia and abnormal stress stimuli. However, sustained insults such as diabetes, hypertension, hemodynamic overload, and atrial fibrillation lead to dysfunctional NOS activity with superoxide produced instead of NO and worse pathophysiology. Recent Advances: Major strides in understanding the role of normal and abnormal constitutive NOS in the heart have revealed molecular targets by which NO modulates myocyte function and morphology, the role and nature of post-translational modifications of NOS, and factors controlling nitroso-redox balance. Localized and differential signaling from NOS1 (neuronal) versus NOS3 (endothelial) isoforms are being identified, as are methods to restore NOS function in heart disease. Critical Issues: Abnormal NOS signaling plays a key role in many cardiac disorders, while targeted modulation may potentially reverse this pathogenic source of oxidative stress. Future Directions: Improvements in the clinical translation of potent modulators of NOS function/dysfunction may ultimately provide a powerful new treatment for many hearts diseases that are fueled by nitroso-redox imbalance. Antioxid. Redox Signal. 18, 1078–1099. PMID:22871241

  3. Human Isoprenoid Synthase Enzymes as Therapeutic Targets

    NASA Astrophysics Data System (ADS)

    Park, Jaeok; Matralis, Alexios; Berghuis, Albert; Tsantrizos, Youla

    2014-07-01

    The complex biochemical network known as the mevalonate pathway is responsible for the biosynthesis of all isoprenoids in the human body, which consists of a vast array of metabolites that are vital for proper cellular functions. Two key isoprenoids, farnesyl pyrophosphate (FPP) and geranylgeranyl pyrophosphate (GGPP) are responsible for the post-translational prenylation of small GTP-binding proteins, and serve as the biosynthetic precursors to numerous other biomolecules. The down-stream metabolite of FPP and GGPP is squalene, the precursor to steroids, bile acids, lipoproteins and vitamin D. In the past, interest in prenyl synthase inhibitors focused mainly on the role of the FPP in lytic bone diseases. More recently, pre-clinical and clinical studies have strongly implicated high levels of protein prenylation in a plethora of human diseases, including non-skeletal cancers, the progression of neurodegenerative diseases and cardiovascular diseases. In this review, we focus mainly on the potential therapeutic value of down-regulating the biosynthesis of FPP, GGPP and squalene. We summarize the most recent drug discovery efforts and the structural data available that support the current on-going studies.

  4. Human isoprenoid synthase enzymes as therapeutic targets

    PubMed Central

    Park, Jaeok; Matralis, Alexios N.; Berghuis, Albert M.; Tsantrizos, Youla S.

    2014-01-01

    In the human body, the complex biochemical network known as the mevalonate pathway is responsible for the biosynthesis of all isoprenoids, which consists of a vast array of metabolites that are vital for proper cellular functions. Two key isoprenoids, farnesyl pyrophosphate (FPP) and geranylgeranyl pyrophosphate (GGPP) are responsible for the post-translational prenylation of small GTP-binding proteins, and serve as the biosynthetic precursors to numerous other biomolecules. The down-stream metabolite of FPP and GGPP is squalene, the precursor to steroids, bile acids, lipoproteins, and vitamin D. In the past, interest in prenyl synthase inhibitors focused mainly on the role of the FPP in lytic bone diseases. More recently pre-clinical and clinical studies have strongly implicated high levels of protein prenylation in a plethora of human diseases, including non-skeletal cancers, the progression of neurodegenerative diseases and cardiovascular diseases. In this review, we focus mainly on the potential therapeutic value of down-regulating the biosynthesis of FPP, GGPP, and squalene. We summarize the most recent drug discovery efforts and the structural data available that support the current on-going studies. PMID:25101260

  5. Tapentadol and nitric oxide synthase systems.

    PubMed

    Bujalska-Zadrożny, Magdalena; Wolińska, Renata; Gąsińska, Emilia; Nagraba, Łukasz

    2015-04-01

    Tapentadol, a new analgesic drug with a dual mechanism of action (μ-opioid receptor agonism and norepinephrine reuptake inhibition), is indicated for the treatment of moderate to severe acute and chronic pain. In this paper, the possible additional involvement of the nitric oxide synthase (NOS) system in the antinociceptive activity of tapentadol was investigated using an unspecific inhibitor of NOS, L-NOArg, a relatively specific inhibitor of neuronal NOS, 7-NI, a relatively selective inhibitor of inducible NOS, L-NIL, and a potent inhibitor of endothelial NOS, L-NIO. Tapentadol (1-10 mg/kg, intraperitoneal) increased the threshold for mechanical (Randall-Selitto test) and thermal (tail-flick test) nociceptive stimuli in a dose-dependent manner. All four NOS inhibitors, administered intraperitoneally in the dose range 0.1-10 mg/kg, potentiated the analgesic action of tapentadol at a low dose of 2 mg/kg in both models of pain. We conclude that NOS systems participate in tapentadol analgesia. PMID:25485639

  6. Undecaprenyl diphosphate synthase inhibitors: antibacterial drug leads.

    PubMed

    Sinko, William; Wang, Yang; Zhu, Wei; Zhang, Yonghui; Feixas, Ferran; Cox, Courtney L; Mitchell, Douglas A; Oldfield, Eric; McCammon, J Andrew

    2014-07-10

    There is a significant need for new antibiotics due to the rise in drug resistance. Drugs such as methicillin and vancomycin target bacterial cell wall biosynthesis, but methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococci (VRE) have now arisen and are of major concern. Inhibitors acting on new targets in cell wall biosynthesis are thus of particular interest since they might also restore sensitivity to existing drugs, and the cis-prenyl transferase undecaprenyl diphosphate synthase (UPPS), essential for lipid I, lipid II, and thus, peptidoglycan biosynthesis, is one such target. We used 12 UPPS crystal structures to validate virtual screening models and then assayed 100 virtual hits (from 450,000 compounds) against UPPS from S. aureus and Escherichia coli. The most promising inhibitors (IC50 ∼2 μM, Ki ∼300 nM) had activity against MRSA, Listeria monocytogenes, Bacillus anthracis, and a vancomycin-resistant Enterococcus sp. with MIC or IC50 values in the 0.25-4 μg/mL range. Moreover, one compound (1), a rhodanine with close structural similarity to the commercial diabetes drug epalrestat, exhibited good activity as well as a fractional inhibitory concentration index (FICI) of 0.1 with methicillin against the community-acquired MRSA USA300 strain, indicating strong synergism. PMID:24827744

  7. Electric Field Driven Torque in ATP Synthase

    PubMed Central

    Miller, John H.; Rajapakshe, Kimal I.; Infante, Hans L.; Claycomb, James R.

    2013-01-01

    FO-ATP synthase (FO) is a rotary motor that converts potential energy from ions, usually protons, moving from high- to low-potential sides of a membrane into torque and rotary motion. Here we propose a mechanism whereby electric fields emanating from the proton entry and exit channels act on asymmetric charge distributions in the c-ring, due to protonated and deprotonated sites, and drive it to rotate. The model predicts a scaling between time-averaged torque and proton motive force, which can be hindered by mutations that adversely affect the channels. The torque created by the c-ring of FO drives the γ-subunit to rotate within the ATP-producing complex (F1) overcoming, with the aid of thermal fluctuations, an opposing torque that rises and falls with angular position. Using the analogy with thermal Brownian motion of a particle in a tilted washboard potential, we compute ATP production rates vs. proton motive force. The latter shows a minimum, needed to drive ATP production, which scales inversely with the number of proton binding sites on the c-ring. PMID:24040370

  8. Catalytic site interactions in yeast OMP synthase.

    PubMed

    Hansen, Michael Riis; Barr, Eric W; Jensen, Kaj Frank; Willemoës, Martin; Grubmeyer, Charles; Winther, Jakob R

    2014-01-15

    The enigmatic kinetics, half-of-the-sites binding, and structural asymmetry of the homodimeric microbial OMP synthases (orotate phosphoribosyltransferase, EC 2.4.2.10) have been proposed to result from an alternating site mechanism in these domain-swapped enzymes [R.W. McClard et al., Biochemistry 45 (2006) 5330-5342]. This behavior was investigated in the yeast enzyme by mutations in the conserved catalytic loop and 5-phosphoribosyl-1-diphosphate (PRPP) binding motif. Although the reaction is mechanistically sequential, the wild-type (WT) enzyme shows parallel lines in double reciprocal initial velocity plots. Replacement of Lys106, the postulated intersubunit communication device, produced intersecting lines in kinetic plots with a 2-fold reduction of kcat. Loop (R105G K109S H111G) and PRPP-binding motif (D131N D132N) mutant proteins, each without detectable enzymatic activity and ablated ability to bind PRPP, complemented to produce a heterodimer with a single fully functional active site showing intersecting initial velocity plots. Equilibrium binding of PRPP and orotidine 5'-monophosphate showed a single class of two binding sites per dimer in WT and K106S enzymes. Evidence here shows that the enzyme does not follow half-of-the-sites cooperativity; that interplay between catalytic sites is not an essential feature of the catalytic mechanism; and that parallel lines in steady-state kinetics probably arise from tight substrate binding. PMID:24262852

  9. RHIC spin flipper AC dipole controller

    SciTech Connect

    Oddo, P.; Bai, M.; Dawson, C.; Gassner, D.; Harvey, M.; Hayes, T.; Mernick, K.; Minty, M.; Roser, T.; Severino, F.; Smith, K.

    2011-03-28

    The RHIC Spin Flipper's five high-Q AC dipoles which are driven by a swept frequency waveform require precise control of phase and amplitude during the sweep. This control is achieved using FPGA based feedback controllers. Multiple feedback loops are used to and dynamically tune the magnets. The current implementation and results will be presented. Work on a new spin flipper for RHIC (Relativistic Heavy Ion Collider) incorporating multiple dynamically tuned high-Q AC-dipoles has been developed for RHIC spin-physics experiments. A spin flipper is needed to cancel systematic errors by reversing the spin direction of the two colliding beams multiple times during a store. The spin flipper system consists of four DC-dipole magnets (spin rotators) and five AC-dipole magnets. Multiple AC-dipoles are needed to localize the driven coherent betatron oscillation inside the spin flipper. Operationally the AC-dipoles form two swept frequency bumps that minimize the effect of the AC-dipole dipoles outside of the spin flipper. Both AC bumps operate at the same frequency, but are phase shifted from each other. The AC-dipoles therefore require precise control over amplitude and phase making the implementation of the AC-dipole controller the central challenge.

  10. ac electroosmosis in rectangular microchannels.

    PubMed

    Campisi, Michele; Accoto, Dino; Dario, Paolo

    2005-11-22

    Motivated by the growing interest in ac electroosmosis as a reliable no moving parts strategy to control fluid motion in microfluidic devices for biomedical applications, such as lab-on-a-chip, we study transient and steady-state electrokinetic phenomena (electroosmosis and streaming currents) in infinitely extended rectangular charged microchannels. With the aid of Fourier series and Laplace transforms we provide a general formal solution of the problem, which is used to study the time-dependent response to sudden ac applied voltage differences in case of finite electric double layer. The Debye-Huckel approximation has been adopted to allow for an algebraic solution of the Poisson-Boltzmann problem in Fourier space. We obtain the expressions of flow velocity profiles, flow rates, streaming currents, as well as expressions of the complex hydraulic and electrokinetic conductances. We analyze in detail the dependence of the electrokinetic conductance on the extension of linear dimensions relative to the Debye length, with an eye on finite electric double layer effects. PMID:16351310

  11. Single event AC - DC electrospraying

    NASA Astrophysics Data System (ADS)

    Stachewicz, U.; Dijksman, J. F.; Marijnissen, J. C. M.

    2008-12-01

    Electrospraying is an innovative method to deposit very small amounts of, for example, biofluids (far less than 1 p1) that include DNA or protein molecules. An electric potential is applied between a nozzle filled with liquid and a counter electrode placed at 1-2 millimeter distance from the nozzle. In our set-up we use an AC field superposed on a DC field to control the droplet generation process. Our approach is to create single events of electrospraying triggered by one single AC pulse. During this pulse, the equilibrium meniscus (determined by surface tension, static pressure and the DC field) of the liquid changes rapidly into a cone and subsequently into a jet formed at the cone apex. Next, the jet breaks-up into fine droplets and the spraying stops. The meniscus returns to its equilibrium shape again. So far we obtained a stable and reproducible single event process for ethanol and ethylene glycol with water using glass pipettes. The results will be used to generate droplets on demand in a controlled way and deposit them on a pre-defined place on the substrate.

  12. Binding Modes of Zaragozic Acid A to Human Squalene Synthase and Staphylococcal Dehydrosqualene Synthase*

    PubMed Central

    Liu, Chia-I; Jeng, Wen-Yih; Chang, Wei-Jung; Ko, Tzu-Ping; Wang, Andrew H.-J.

    2012-01-01

    Zaragozic acids (ZAs) belong to a family of fungal metabolites with nanomolar inhibitory activity toward squalene synthase (SQS). The enzyme catalyzes the committed step of sterol synthesis and has attracted attention as a potential target for antilipogenic and antiinfective therapies. Here, we have determined the structure of ZA-A complexed with human SQS. ZA-A binding induces a local conformational change in the substrate binding site, and its C-6 acyl group also extends over to the cofactor binding cavity. In addition, ZA-A effectively inhibits a homologous bacterial enzyme, dehydrosqualene synthase (CrtM), which synthesizes the precursor of staphyloxanthin in Staphylococcus aureus to cope with oxidative stress. Size reduction at Tyr248 in CrtM further increases the ZA-A binding affinity, and it reveals a similar overall inhibitor binding mode to that of human SQS/ZA-A except for the C-6 acyl group. These structures pave the way for further improving selectivity and development of a new generation of anticholesterolemic and antimicrobial inhibitors. PMID:22474324

  13. Binding modes of zaragozic acid A to human squalene synthase and staphylococcal dehydrosqualene synthase.

    PubMed

    Liu, Chia-I; Jeng, Wen-Yih; Chang, Wei-Jung; Ko, Tzu-Ping; Wang, Andrew H-J

    2012-05-25

    Zaragozic acids (ZAs) belong to a family of fungal metabolites with nanomolar inhibitory activity toward squalene synthase (SQS). The enzyme catalyzes the committed step of sterol synthesis and has attracted attention as a potential target for antilipogenic and antiinfective therapies. Here, we have determined the structure of ZA-A complexed with human SQS. ZA-A binding induces a local conformational change in the substrate binding site, and its C-6 acyl group also extends over to the cofactor binding cavity. In addition, ZA-A effectively inhibits a homologous bacterial enzyme, dehydrosqualene synthase (CrtM), which synthesizes the precursor of staphyloxanthin in Staphylococcus aureus to cope with oxidative stress. Size reduction at Tyr(248) in CrtM further increases the ZA-A binding affinity, and it reveals a similar overall inhibitor binding mode to that of human SQS/ZA-A except for the C-6 acyl group. These structures pave the way for further improving selectivity and development of a new generation of anticholesterolemic and antimicrobial inhibitors. PMID:22474324

  14. A Combinatorial Interplay Among the 1-Aminocyclopropane-1-carboxylate Isoforms Regulates Ethylene Biosynthesis in Arabidopsis thaliana

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ethylene (C2H4) is a unique plant-signaling molecule that regulates numerous developmental processes. The key enzyme in the two-step biosynthetic pathway of ethylene is 1-aminocyclopropane-1-carboxylate synthase (ACS), which catalyzes the conversion of Sadenosyl-methionine (AdoMet) to ACC, the precu...

  15. Characterisation of the tryptophan synthase alpha subunit in maize

    PubMed Central

    Kriechbaumer, Verena; Weigang, Linda; Fießelmann, Andreas; Letzel, Thomas; Frey, Monika; Gierl, Alfons; Glawischnig, Erich

    2008-01-01

    Background In bacteria, such as Salmonella typhimurium, tryptophan is synthesized from indole-3-glycerole phosphate (IGP) by a tryptophan synthase αββα heterotetramer. Plants have evolved multiple α (TSA) and β (TSB) homologs, which have probably diverged in biological function and their ability of subunit interaction. There is some evidence for a tryptophan synthase (TS) complex in Arabidopsis. On the other hand maize (Zea mays) expresses the TSA-homologs BX1 and IGL that efficiently cleave IGP, independent of interaction with TSB. Results In order to clarify, how tryptophan is synthesized in maize, two TSA homologs, hitherto uncharacterized ZmTSA and ZmTSAlike, were functionally analyzed. ZmTSA is localized in plastids, the major site of tryptophan biosynthesis in plants. It catalyzes the tryptophan synthase α-reaction (cleavage of IGP), and forms a tryptophan synthase complex with ZmTSB1 in vitro. The catalytic efficiency of the α-reaction is strongly enhanced upon complex formation. A 160 kD tryptophan synthase complex was partially purified from maize leaves and ZmTSA was identified as native α-subunit of this complex by mass spectrometry. ZmTSAlike, for which no in vitro activity was detected, is localized in the cytosol. ZmTSAlike, BX1, and IGL were not detectable in the native tryptophan synthase complex in leaves. Conclusion It was demonstrated in vivo and in vitro that maize forms a tryptophan synthase complex and ZmTSA functions as α-subunit in this complex. PMID:18430213

  16. The Tomato Terpene Synthase Gene Family1[W][OA

    PubMed Central

    Falara, Vasiliki; Akhtar, Tariq A.; Nguyen, Thuong T.H.; Spyropoulou, Eleni A.; Bleeker, Petra M.; Schauvinhold, Ines; Matsuba, Yuki; Bonini, Megan E.; Schilmiller, Anthony L.; Last, Robert L.; Schuurink, Robert C.; Pichersky, Eran

    2011-01-01

    Compounds of the terpenoid class play numerous roles in the interactions of plants with their environment, such as attracting pollinators and defending the plant against pests. We show here that the genome of cultivated tomato (Solanum lycopersicum) contains 44 terpene synthase (TPS) genes, including 29 that are functional or potentially functional. Of these 29 TPS genes, 26 were expressed in at least some organs or tissues of the plant. The enzymatic functions of eight of the TPS proteins were previously reported, and here we report the specific in vitro catalytic activity of 10 additional tomato terpene synthases. Many of the tomato TPS genes are found in clusters, notably on chromosomes 1, 2, 6, 8, and 10. All TPS family clades previously identified in angiosperms are also present in tomato. The largest clade of functional TPS genes found in tomato, with 12 members, is the TPS-a clade, and it appears to encode only sesquiterpene synthases, one of which is localized to the mitochondria, while the rest are likely cytosolic. A few additional sesquiterpene synthases are encoded by TPS-b clade genes. Some of the tomato sesquiterpene synthases use z,z-farnesyl diphosphate in vitro as well, or more efficiently than, the e,e-farnesyl diphosphate substrate. Genes encoding monoterpene synthases are also prevalent, and they fall into three clades: TPS-b, TPS-g, and TPS-e/f. With the exception of two enzymes involved in the synthesis of ent-kaurene, the precursor of gibberellins, no other tomato TPS genes could be demonstrated to encode diterpene synthases so far. PMID:21813655

  17. The distribution of acetohydroxyacid synthase in soil bacteria.

    PubMed

    Nelson, Darryl R; Duxbury, Trevor

    2008-01-01

    Most bacteria possess the enzyme acetohydroxyacid synthase, which is used to produce branched-chain amino acids. Enteric bacteria contain several isozymes suited to different conditions, but the distribution of acetohydroxyacid synthase in soil bacteria is largely unknown. Growth experiments confirmed that Escherichia coli, Salmonella enterica serotype Typhimurium, and Enterobacter aerogenes contain isozymes of acetohydroxyacid synthase, allowing the bacteria to grow in the presence of valine (which causes feedback inhibition of AHAS I) or the sulfonylurea herbicide triasulfuron (which inhibits AHAS II) although a slight lag phase was observed in growth in the latter case. Several common soil isolates were inhibited by triasulfuron, but Pseudomonas fluorescens and Rhodococcus erythropolis were not inhibited by any combination of triasulfuron and valine. The extent of sulfonylurea-sensitive acetohydroxyacid synthase in soil was revealed when 21 out of 27 isolated bacteria in pure culture were inhibited by triasulfuron, the addition of isoleucine and/or valine reversing the effect in 19 cases. Primers were designed to target the genes encoding the large subunits (ilvB, ilvG and ilvI) of acetohydroxyacid synthase from available sequence data and a approximately 355 bp fragment in Bacillus subtilis, Arthrobacter globiformis, E. coli and S. enterica was subsequently amplified. The primers were used to create a small clone library of sequences from an agricultural soil. Phylogenetic analysis revealed significant sequence variation, but all 19 amino acid sequences were most closely related to published large subunit acetohydroxyacid synthase amino acid sequences within several phyla including the Proteobacteria and Actinobacteria. The results suggested the majority of soil microorganisms contain only one functional acetohydroxyacid synthase enzyme sensitive to sulfonylurea herbicides. PMID:17624809

  18. Characterization of Lipoyl Synthase from Mycobacterium tuberculosis.

    PubMed

    Lanz, Nicholas D; Lee, Kyung-Hoon; Horstmann, Abigail K; Pandelia, Maria-Eirini; Cicchillo, Robert M; Krebs, Carsten; Booker, Squire J

    2016-03-01

    The prevalence of multiple and extensively drug-resistant strains of Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis, is on the rise, necessitating the identification of new targets to combat an organism that has infected one-third of the world's population, according to the World Health Organization. The biosynthesis of the lipoyl cofactor is one possible target, given its critical importance in cellular metabolism and the apparent lack of functional salvage pathways in Mtb that are found in humans and many other organisms. The lipoyl cofactor is synthesized de novo in two committed steps, involving the LipB-catalyzed transfer of an octanoyl chain derived from fatty acid biosynthesis to a lipoyl carrier protein and the LipA-catalyzed insertion of sulfur atoms at C6 and C8 of the octanoyl chain. A number of in vitro studies of lipoyl synthases from Escherichia coli, Sulfolobus solfataricus, and Thermosynechococcus elongatus have been conducted, but the enzyme from Mtb has not been characterized. Herein, we show that LipA from Mtb contains two [4Fe-4S] clusters and converts an octanoyl peptide substrate to the corresponding lipoyl peptide product via the same C6-monothiolated intermediate as that observed in the E. coli LipA reaction. In addition, we show that LipA from Mtb forms a complex with the H protein of the glycine cleavage system and that the strength of association is dependent on the presence of S-adenosyl-l-methionine. We also show that LipA from Mtb can complement a lipA mutant of E. coli, demonstrating the commonalities of the two enzymes. Lastly, we show that the substrate for LipA, which normally acts on a post-translationally modified protein, can be reduced to carboxybenzyl-octanoyllysine. PMID:26841001

  19. Nitric oxide synthases: structure, function and inhibition.

    PubMed Central

    Alderton, W K; Cooper, C E; Knowles, R G

    2001-01-01

    This review concentrates on advances in nitric oxide synthase (NOS) structure, function and inhibition made in the last seven years, during which time substantial advances have been made in our understanding of this enzyme family. There is now information on the enzyme structure at all levels from primary (amino acid sequence) to quaternary (dimerization, association with other proteins) structure. The crystal structures of the oxygenase domains of inducible NOS (iNOS) and vascular endothelial NOS (eNOS) allow us to interpret other information in the context of this important part of the enzyme, with its binding sites for iron protoporphyrin IX (haem), biopterin, L-arginine, and the many inhibitors which interact with them. The exact nature of the NOS reaction, its mechanism and its products continue to be sources of controversy. The role of the biopterin cofactor is now becoming clearer, with emerging data implicating one-electron redox cycling as well as the multiple allosteric effects on enzyme activity. Regulation of the NOSs has been described at all levels from gene transcription to covalent modification and allosteric regulation of the enzyme itself. A wide range of NOS inhibitors have been discussed, interacting with the enzyme in diverse ways in terms of site and mechanism of inhibition, time-dependence and selectivity for individual isoforms, although there are many pitfalls and misunderstandings of these aspects. Highly selective inhibitors of iNOS versus eNOS and neuronal NOS have been identified and some of these have potential in the treatment of a range of inflammatory and other conditions in which iNOS has been implicated. PMID:11463332

  20. Tertiary model of a plant cellulose synthase

    PubMed Central

    Sethaphong, Latsavongsakda; Haigler, Candace H.; Kubicki, James D.; Zimmer, Jochen; Bonetta, Dario; DeBolt, Seth; Yingling, Yaroslava G.

    2013-01-01

    A 3D atomistic model of a plant cellulose synthase (CESA) has remained elusive despite over forty years of experimental effort. Here, we report a computationally predicted 3D structure of 506 amino acids of cotton CESA within the cytosolic region. Comparison of the predicted plant CESA structure with the solved structure of a bacterial cellulose-synthesizing protein validates the overall fold of the modeled glycosyltransferase (GT) domain. The coaligned plant and bacterial GT domains share a six-stranded β-sheet, five α-helices, and conserved motifs similar to those required for catalysis in other GT-2 glycosyltransferases. Extending beyond the cross-kingdom similarities related to cellulose polymerization, the predicted structure of cotton CESA reveals that plant-specific modules (plant-conserved region and class-specific region) fold into distinct subdomains on the periphery of the catalytic region. Computational results support the importance of the plant-conserved region and/or class-specific region in CESA oligomerization to form the multimeric cellulose–synthesis complexes that are characteristic of plants. Relatively high sequence conservation between plant CESAs allowed mapping of known mutations and two previously undescribed mutations that perturb cellulose synthesis in Arabidopsis thaliana to their analogous positions in the modeled structure. Most of these mutation sites are near the predicted catalytic region, and the confluence of other mutation sites supports the existence of previously undefined functional nodes within the catalytic core of CESA. Overall, the predicted tertiary structure provides a platform for the biochemical engineering of plant CESAs. PMID:23592721

  1. The multiphoton AC Stark effect

    NASA Astrophysics Data System (ADS)

    Rudolph, T. G.; Ficek, Z.; Freedhoff, H. S.

    1998-02-01

    We study the interaction of a two-level atom with two intense lasers: a strong laser of Rabi frequency 2Ω on resonance with the atomic transition, and a weaker laser detuned by 2Ω/n, i.e. by a subharmonic of the Rabi frequency of the first. The second laser "dresses" the dressed states created by the first in an n-photon process. We calculate the energy levels and eigenstates of this "doubly-dressed" atom, and find a new phenomenon: the splitting of the energy levels due to an n-photon coupling between them, resulting in a multiphoton AC Stark effect. We illustrate this effect in the fluorescence spectrum, and show that the spectrum contains triplets at the subharmonic as well as harmonic resonance frequencies with a clear dependence on the order n of the resonance and the ratio α of the Rabi frequencies of the lasers

  2. Protection of superconducting AC windings

    SciTech Connect

    Verhaege, T.; Agnoux, C.; Tavergnier, J.P. ); Lacaze, A. ); Collet, M. )

    1992-01-01

    Recent progresses on multifilamentary wires open new prospects of 50-60 Hz applications for superconductivity. The problem of AC windings protection is more critical than that of DC windings, because of high current densities, and of high matrix resistivity: one should not allow the quenched wire to carry it nominal current for longer than a few milliseconds, otherwise permanent damage could occur. After a quench initiation, the protection system therefore has to switch off or drastically reduce the current very rapidly. In this paper, the authors propose various schemes, applicable when the conductor is made of several wires: active protection involves an ultra-rapid quench detection. It is based on the measurement of the current passing through the central resistive wire, and/or of unbalanced currents in the different superconducting wires. About 20 milliseconds after detection, a fast circuit-breaker switched off the current. A complementary passive protection is provided by the resistance developing during normal phase propagation.

  3. Highly Divergent Mitochondrial ATP Synthase Complexes in Tetrahymena thermophila

    PubMed Central

    Balabaskaran Nina, Praveen; Dudkina, Natalya V.; Kane, Lesley A.; van Eyk, Jennifer E.; Boekema, Egbert J.; Mather, Michael W.; Vaidya, Akhil B.

    2010-01-01

    The F-type ATP synthase complex is a rotary nano-motor driven by proton motive force to synthesize ATP. Its F1 sector catalyzes ATP synthesis, whereas the Fo sector conducts the protons and provides a stator for the rotary action of the complex. Components of both F1 and Fo sectors are highly conserved across prokaryotes and eukaryotes. Therefore, it was a surprise that genes encoding the a and b subunits as well as other components of the Fo sector were undetectable in the sequenced genomes of a variety of apicomplexan parasites. While the parasitic existence of these organisms could explain the apparent incomplete nature of ATP synthase in Apicomplexa, genes for these essential components were absent even in Tetrahymena thermophila, a free-living ciliate belonging to a sister clade of Apicomplexa, which demonstrates robust oxidative phosphorylation. This observation raises the possibility that the entire clade of Alveolata may have invented novel means to operate ATP synthase complexes. To assess this remarkable possibility, we have carried out an investigation of the ATP synthase from T. thermophila. Blue native polyacrylamide gel electrophoresis (BN-PAGE) revealed the ATP synthase to be present as a large complex. Structural study based on single particle electron microscopy analysis suggested the complex to be a dimer with several unique structures including an unusually large domain on the intermembrane side of the ATP synthase and novel domains flanking the c subunit rings. The two monomers were in a parallel configuration rather than the angled configuration previously observed in other organisms. Proteomic analyses of well-resolved ATP synthase complexes from 2-D BN/BN-PAGE identified orthologs of seven canonical ATP synthase subunits, and at least 13 novel proteins that constitute subunits apparently limited to the ciliate lineage. A mitochondrially encoded protein, Ymf66, with predicted eight transmembrane domains could be a substitute for the subunit a

  4. Argininosuccinate synthase: at the center of arginine metabolism

    PubMed Central

    Haines, Ricci J.; Pendleton, Laura C.; Eichler, Duane C.

    2011-01-01

    The levels of L-arginine, a cationic, semi-essential amino acid, are often controlled within a cell at the level of local availability through biosynthesis. The importance of this temporal and spatial control of cellular L-arginine is highlighted by the tissue specific roles of argininosuccinate synthase (argininosuccinate synthetase) (EC 6.3.4.5), as the rate-limiting step in the conversion of L-citrulline to L-arginine. Since its discovery, the function of argininosuccinate synthase has been linked almost exclusively to hepatic urea production despite the fact that alternative pathways involving argininosuccinate synthase were defined, such as its role in providing arginine for creatine and for polyamine biosynthesis. However, it was the discovery of nitric oxide that meaningfully extended our understanding of the metabolic importance of non-hepatic argininosuccinate synthase. Indeed, our knowledge of the number of tissues that manage distinct pools of arginine under the control of argininosuccinate synthase has expanded significantly. PMID:21494411

  5. Sucrose Phosphate Synthase and Sucrose Accumulation at Low Temperature 1

    PubMed Central

    Guy, Charles L.; Huber, Joan L. A.; Huber, Steven C.

    1992-01-01

    The influence of growth temperature on the free sugar and sucrose phosphate synthase content and activity of spinach (Spinacia oleracea) leaf tissue was studied. When plants were grown at 25°C for 3 weeks and then transferred to a constant 5°C, sucrose, glucose, and fructose accumulated to high levels during a 14-d period. Predawn sugar levels increased from 14- to 20-fold over the levels present at the outset of the low-temperature treatment. Sucrose was the most abundant free sugar before, during, and after exposure to 5°C. Leaf sucrose phosphate synthase activity was significantly increased by the low-temperature treatment, whereas sucrose synthase and invertases were not. Synthesis of the sucrose phosphate synthase subunit was increased during and after low-temperature exposure and paralleled an increase in the steady-state level of the subunit. The increases in sucrose and its primary biosynthetic enzyme, sucrose phosphate synthase, are discussed in relation to adjustment of metabolism to low nonfreezing temperature and freezing stress tolerance. Images Figure 1 Figure 2 Figure 3 PMID:16652990

  6. Plasticity and Evolution of (+)-3-Carene Synthase and (−)-Sabinene Synthase Functions of a Sitka Spruce Monoterpene Synthase Gene Family Associated with Weevil Resistance*

    PubMed Central

    Roach, Christopher R.; Hall, Dawn E.; Zerbe, Philipp; Bohlmann, Jörg

    2014-01-01

    The monoterpene (+)-3-carene is associated with resistance of Sitka spruce against white pine weevil, a major North American forest insect pest of pine and spruce. High and low levels of (+)-3-carene in, respectively, resistant and susceptible Sitka spruce genotypes are due to variation of (+)-3-carene synthase gene copy number, transcript and protein expression levels, enzyme product profiles, and enzyme catalytic efficiency. A family of multiproduct (+)-3-carene synthase-like genes of Sitka spruce include the three (+)-3-carene synthases, PsTPS-3car1, PsTPS-3car2, PsTPS-3car3, and the (−)-sabinene synthase PsTPS-sab. Of these, PsTPS-3car2 is responsible for the relatively higher levels of (+)-3-carene in weevil-resistant trees. Here, we identified features of the PsTPS-3car1, PsTPS-3car2, PsTPS-3car3, and PsTPS-sab proteins that determine different product profiles. A series of domain swap and site-directed mutations, supported by structural comparisons, identified the amino acid in position 596 as critical for product profiles dominated by (+)-3-carene in PsTPS-3car1, PsTPS-3car2, and PsTPS-3car3, or (−)-sabinene in PsTPS-sab. A leucine in this position promotes formation of (+)-3-carene, whereas phenylalanine promotes (−)-sabinene. Homology modeling predicts that position 596 directs product profiles through differential stabilization of the reaction intermediate. Kinetic analysis revealed position 596 also plays a role in catalytic efficiency. Mutations of position 596 with different side chain properties resulted in a series of enzymes with different product profiles, further highlighting the inherent plasticity and potential for evolution of alternative product profiles of these monoterpene synthases of conifer defense against insects. PMID:25016016

  7. An active site–tail interaction in the structure of hexahistidine-tagged Thermoplasma acidophilum citrate synthase

    SciTech Connect

    Murphy, Jesse R.; Donini, Stefano; Kappock, T. Joseph

    2015-09-23

    Citrate synthase from the thermophilic euryarchaeon T. acidophilum fused to a hexahistidine tag was purified and biochemically characterized. The structure of the unliganded enzyme at 2.2 Å resolution contains tail–active site contacts in half of the active sites. Citrate synthase (CS) plays a central metabolic role in aerobes and many other organisms. The CS reaction comprises two half-reactions: a Claisen aldol condensation of acetyl-CoA (AcCoA) and oxaloacetate (OAA) that forms citryl-CoA (CitCoA), and CitCoA hydrolysis. Protein conformational changes that ‘close’ the active site play an important role in the assembly of a catalytically competent condensation active site. CS from the thermoacidophile Thermoplasma acidophilum (TpCS) possesses an endogenous Trp fluorophore that can be used to monitor the condensation reaction. The 2.2 Å resolution crystal structure of TpCS fused to a C-terminal hexahistidine tag (TpCSH6) reported here is an ‘open’ structure that, when compared with several liganded TpCS structures, helps to define a complete path for active-site closure. One active site in each dimer binds a neighboring His tag, the first nonsubstrate ligand known to occupy both the AcCoA and OAA binding sites. Solution data collectively suggest that this fortuitous interaction is stabilized by the crystalline lattice. As a polar but almost neutral ligand, the active site–tail interaction provides a new starting point for the design of bisubstrate-analog inhibitors of CS.

  8. Uncovering a dynamically formed substrate access tunnel in carbon monoxide dehydrogenase/acetyl-CoA synthase.

    PubMed

    Wang, Po-hung; Bruschi, Maurizio; De Gioia, Luca; Blumberger, Jochen

    2013-06-26

    The transport of small ligands to active sites of proteins is the basis of vital processes in biology such as enzymatic catalysis and cell signaling, but also of more destructive ones including enzyme inhibition and oxidative damage. Here, we show how a diffusion-reaction model solved by means of molecular dynamics and density functional theory calculations provides novel insight into the transport of small ligands in proteins. In particular, we unravel the existence of an elusive, dynamically formed gas channel, which CO2 takes to diffuse from the solvent to the active site (C-cluster) of the bifunctional multisubunit enzyme complex carbon monoxide dehydrogenase/acetyl-CoA synthase (CODH/ACS). Two cavities forming this channel are temporarily created by protein fluctuations and are not apparent in the X-ray structures. The ligand transport is controlled by two residues at the end of this tunnel, His113 and His116, and occurs on the same time scale on which chemical binding to the active site takes place (0.1-1 ms), resulting in an overall binding rate on the second time scale. We find that upon reduction of CO2 to CO, the newly formed Fe-hydroxy ligand greatly strengthens the hydrogen-bond network, preventing CO from exiting the protein through the same way that CO2 takes to enter the protein. This is the basis for directional transport of CO from the production site (C-cluster of CODH subunit) to the utilization site (A-cluster of ACS subunit). In view of these results, a general picture emerges of how large proteins guide small ligands toward their active sites. PMID:23713976

  9. Asymmetric Total Synthesis of (+)- and (−)-Clusianone and (+)- and (−)Clusianone Methyl Enol Ether via ACC Alkylation and Evaluation of their Anti-HIV Activity

    PubMed Central

    Garnsey, Michelle R.; Matous, James A.; Kwiek, Jesse J.; Coltart, Don M.

    2011-01-01

    The total asymmetric synthesis of (+)- and (−)-clusianone and (+)- and (−)-clusianone methyl enol ether is reported. Asymmetric induction is achieved through the use of ACC alkylation, providing the key intermediates with an er of 99:1. The four synthetic compounds were evaluated for their anti-HIV activity. Both (+)- and (−)-clusianone displayed significant anti-HIV activity. PMID:21414776

  10. Support for a history-dependent predictive model of dACC activity in producing the bivalency effect: an event-related potential study.

    PubMed

    Grundy, John G; Shedden, Judith M

    2014-05-01

    In the present study, we examine electrophysiological correlates of factors influencing an adjustment in cognitive control known as the bivalency effect. During task-switching, the occasional presence of bivalent stimuli in a block of univalent trials is enough to elicit a response slowing on all subsequent univalent trials. Bivalent stimuli can be congruent or incongruent with respect to the response afforded by the irrelevant stimulus feature. Here we show that the incongruent bivalency effect, the congruent bivalency effect, and an effect of a simple violation of expectancy are captured at a frontal ERP component (between 300 and 550ms) associated with ACC activity, and that the unexpectedness effect is distinguished from both congruent and incongruent bivalency effects at an earlier component (100-120ms) associated with the temporal parietal junction. We suggest that the frontal component reflects the dACC's role in predicting future cognitive load based on recent history. In contrast, the posterior component may index early visual feature extraction in response to bivalent stimuli that cue currently ongoing tasks; dACC activity may trigger the temporal parietal activity only when specific task cueing is involved and not for simple violations of expectancy. PMID:24686093

  11. Subcellular localization of dinoflagellate polyketide synthases and fatty acid synthase activity.

    PubMed

    Van Dolah, Frances M; Zippay, Mackenzie L; Pezzolesi, Laura; Rein, Kathleen S; Johnson, Jillian G; Morey, Jeanine S; Wang, Zhihong; Pistocchi, Rossella

    2013-12-01

    Dinoflagellates are prolific producers of polyketide secondary metabolites. Dinoflagellate polyketide synthases (PKSs) have sequence similarity to Type I PKSs, megasynthases that encode all catalytic domains on a single polypeptide. However, in dinoflagellate PKSs identified to date, each catalytic domain resides on a separate transcript, suggesting multiprotein complexes similar to Type II PKSs. Here, we provide evidence through coimmunoprecipitation that single-domain ketosynthase and ketoreductase proteins interact, suggesting a predicted multiprotein complex. In Karenia brevis (C.C. Davis) Gert Hansen & Ø. Moestrup, previously observed chloroplast localization of PKSs suggested that brevetoxin biosynthesis may take place in the chloroplast. Here, we report that PKSs are present in both cytosol and chloroplast. Furthermore, brevetoxin is not present in isolated chloroplasts, raising the question of what chloroplast-localized PKS enzymes might be doing. Antibodies to K. brevis PKSs recognize cytosolic and chloroplast proteins in Ostreopsis cf. ovata Fukuyo, and Coolia monotis Meunier, which produce different suites of polyketide toxins, suggesting that these PKSs may share common pathways. Since PKSs are closely related to fatty acid synthases (FAS), we sought to determine if fatty acid biosynthesis colocalizes with either chloroplast or cytosolic PKSs. [(3) H]acetate labeling showed fatty acids are synthesized in the cytosol, with little incorporation in chloroplasts, consistent with a Type I FAS system. However, although 29 sequences in a K. brevis expressed sequence tag database have similarity (BLASTx e-value <10(-10) ) to PKSs, no transcripts for either Type I (cytosolic) or Type II (chloroplast) FAS are present. Further characterization of the FAS complexes may help to elucidate the functions of the PKS enzymes identified in dinoflagellates. PMID:27007632

  12. Understanding Plant Cellulose Synthases through a Comprehensive Investigation of the Cellulose Synthase Family Sequences

    PubMed Central

    Carroll, Andrew; Specht, Chelsea D.

    2011-01-01

    The development of cellulose as an organizing structure in the plant cell wall was a key event in both the initial colonization and the subsequent domination of the terrestrial ecosystem by vascular plants. A wealth of experimental data has demonstrated the complicated genetic interactions required to form the large synthetic complex that synthesizes cellulose. However, these results are lacking an extensive analysis of the evolution, specialization, and regulation of the proteins that compose this complex. Here we perform an in-depth analysis of the sequences in the cellulose synthase (CesA) family. We investigate the phylogeny of the CesA family, with emphasis on evolutionary specialization. We define specialized clades and identify the class-specific regions within the CesA sequence that may explain this specialization. We investigate changes in regulation of CesAs by looking at the conservation of proposed phosphorylation sites. We investigate the conservation of sites where mutations have been documented that impair CesA function, and compare these sites to those observed in the closest cellulose synthase-like (Csl) families to better understand what regions may separate the CesAs from other Csls. Finally we identify two positions with strong conservation of the aromatic trait, but lacking conservation of amino acid identity, which may represent residues important for positioning the sugar substrate for catalysis. These analyses provide useful tools for understanding characterized mutations and post-translational modifications, and for informing further experiments to probe CesA assembly, regulation, and function through site-directed mutagenesis or domain swapping experiments. PMID:22629257

  13. Deprotonations in the Reaction of Flavin-Dependent Thymidylate Synthase.

    PubMed

    Stull, Frederick W; Bernard, Steffen M; Sapra, Aparna; Smith, Janet L; Zuiderweg, Erik R P; Palfey, Bruce A

    2016-06-14

    Many microorganisms use flavin-dependent thymidylate synthase (FDTS) to synthesize the essential nucleotide 2'-deoxythymidine 5'-monophosphate (dTMP) from 2'-deoxyuridine 5'-monophosphate (dUMP), 5,10-methylenetetrahydrofolate (CH2THF), and NADPH. FDTSs have a structure that is unrelated to the thymidylate synthase used by humans and a very different mechanism. Here we report nuclear magnetic resonance evidence that FDTS ionizes N3 of dUMP using an active-site arginine. The ionized form of dUMP is largely responsible for the changes in the flavin absorbance spectrum of FDTS upon dUMP binding. dUMP analogues also suggest that the phosphate of dUMP acts as the base that removes the proton from C5 of the dUMP-methylene intermediate in the FDTS-catalyzed reaction. These findings establish additional differences between the mechanisms of FDTS and human thymidylate synthase. PMID:27214228

  14. Evolutionary history of the chitin synthases of eukaryotes.

    PubMed

    Morozov, Alexey A; Likhoshway, Yelena V

    2016-06-01

    Chitin synthases are widespread among eukaryotes and known to have a complex evolutionary history in some of the groups. We have reconstructed the chitin synthase phylogeny using the most taxonomically comprehensive dataset currently available and have shown the presence of independently formed paralogous groups in oomycetes, ciliates, fungi, and all diatoms except raphid pennates. There were also two cases of horizontal gene transfer (HGT): transfer from fungus to early diatoms gave rise to diatom paralogous group, while transfer from raphid pennate diatom to Acantamoeba ancestor is, to our knowledge, restricted to a single gene in amoeba. Early evolution of chitin synthases is heavily obscured by paralogy, and further sequencing effort is necessary. PMID:26887391

  15. Divergence of multimodular polyketide synthases revealed by a didomain structure.

    PubMed

    Zheng, Jianting; Gay, Darren C; Demeler, Borries; White, Mark A; Keatinge-Clay, Adrian T

    2012-07-01

    The enoylreductase (ER) is the final common enzyme from modular polyketide synthases (PKSs) to be structurally characterized. The 3.0 Å-resolution structure of the didomain comprising the ketoreductase (KR) and ER from the second module of the spinosyn PKS reveals that ER shares an ∼600-Å(2) interface with KR distinct from that of the related mammalian fatty acid synthase (FAS). In contrast to the ER domains of the mammalian FAS, the ER domains of the second module of the spinosyn PKS do not make contact across the two-fold axis of the synthase. This monomeric organization may have been necessary in the evolution of multimodular PKSs to enable acyl carrier proteins to access each of their cognate enzymes. The isolated ER domain showed activity toward a substrate analog, enabling us to determine the contributions of its active site residues. PMID:22634636

  16. Divergence of multimodular polyketide synthases revealed by a didomain structure

    PubMed Central

    Zheng, Jianting; Gay, Darren C.; Demeler, Borries; White, Mark A.; Keatinge-Clay, Adrian T.

    2012-01-01

    The enoylreductase (ER) is the final common enzyme from modular polyketide synthases (PKSs) to be structurally characterized. The 3.0 Å resolution structure of the didomain comprised of the ketoreductase (KR) and ER from the second module of the spinosyn PKS reveals that ER shares an ~600 Å2 interface with KR distinct from that of the related mammalian fatty acid synthase (FAS). In contrast to the ER domains of the mammalian FAS, the ER domains of the second module of the spinosyn PKS do not make contact across the twofold axis of the synthase. This monomeric organization may have been necessary in the evolution of multimodular PKSs to enable acyl carrier proteins (ACPs) to access each of their cognate enzymes. The isolated ER domain showed activity towards a substrate analog, enabling the contributions of its active site residues to be determined. PMID:22634636

  17. Plant terpenoid synthases: Molecular biology and phylogenetic analysis

    PubMed Central

    Bohlmann, Jörg; Meyer-Gauen, Gilbert; Croteau, Rodney

    1998-01-01

    This review focuses on the monoterpene, sesquiterpene, and diterpene synthases of plant origin that use the corresponding C10, C15, and C20 prenyl diphosphates as substrates to generate the enormous diversity of carbon skeletons characteristic of the terpenoid family of natural products. A description of the enzymology and mechanism of terpenoid cyclization is followed by a discussion of molecular cloning and heterologous expression of terpenoid synthases. Sequence relatedness and phylogenetic reconstruction, based on 33 members of the Tps gene family, are delineated, and comparison of important structural features of these enzymes is provided. The review concludes with an overview of the organization and regulation of terpenoid metabolism, and of the biotechnological applications of terpenoid synthase genes. PMID:9539701

  18. Synthase-dependent exopolysaccharide secretion in Gram-negative bacteria

    PubMed Central

    Whitney, J.C.; Howell, P.L.

    2014-01-01

    The biosynthesis and export of bacterial cell-surface polysaccharides is known to occur through several distinct mechanisms. Recent advances in the biochemistry and structural biology of several proteins in synthase-dependent polysaccharide secretion systems have identified key conserved components of this pathway in Gram-negative bacteria. These components include an inner-membrane-embedded polysaccharide synthase, a periplasmic tetratricopeptide repeat (TPR)-containing scaffold protein, and an outer-membrane β-barrel porin. There is also increasing evidence that many synthase-dependent systems are post-translationally regulated by the bacterial second messenger bis-(3′-5′)-cyclic dimeric guanosine monophosphate (c-di-GMP). Here, we compare these core proteins in the context of the alginate, cellulose, and poly-β-D-N-acetylglucosamine (PNAG) secretion systems. PMID:23117123

  19. Deep sea water modulates blood pressure and exhibits hypolipidemic effects via the AMPK-ACC pathway: an in vivo study.

    PubMed

    Sheu, Ming-Jyh; Chou, Pei-Yu; Lin, Wen-Hsin; Pan, Chun-Hsu; Chien, Yi-Chung; Chung, Yun-Lung; Liu, Fon-Chang; Wu, Chieh-Hsi

    2013-06-01

    Deep sea water (DSW), originally pumped from the Pacific Rim off the coast of Hualien County (Taiwan), and its mineral constituents, were concentrated by a low-temperature vacuum evaporation system to produce a hardness of approximately 400,000 mg/L of seawater mineral concentrate. The primary composition of this seawater mineral concentrate was ionic magnesium (Mg²⁺), which was approximately 96,000 mg/L. Referring to the human recommended daily allowance (RDA) of magnesium, we diluted the mineral concentrate to three different dosages: 0.1 × DSW (equivalent to 3.75 mg Mg²⁺/kg DSW); 1 × DSW (equivalent to 37.5 mg Mg²⁺/kg DSW); and 2 × DSW (equivalent to 75 mg Mg²⁺/kg DSW). Additionally, a magnesium chloride treatment was conducted for comparison with the DSW supplement. The study indicated that 0.1 × DSW, 1 × DSW and 2 × DSW decreased the systolic and diastolic pressures in spontaneous hypertensive rats in an eight-week experiment. DSW has been shown to reduce serum lipids and prevent atherogenesis in a hypercholesterolemic rabbit model. Our results demonstrated that 1 × DSW and 2 × DSW significantly suppressed the serum cholesterol levels, reduced the lipid accumulation in liver tissues, and limited aortic fatty streaks. These findings indicated that the antiatherogenic effects of DSW are associated with 5'-adenosine monophosphate-activated protein kinase (AMPK) stimulation and the consequent inhibition of phosphorylation of acetyl-CoA carboxylase (ACC) in atherosclerotic rabbits. We hypothesize that DSW could potentially be used as drinking water because it modulates blood pressure, reduces lipids, and prevents atherogenesis. PMID:23774889

  20. Mapping a kingdom-specific functional domain of squalene synthase.

    PubMed

    Linscott, Kristin B; Niehaus, Thomas D; Zhuang, Xun; Bell, Stephen A; Chappell, Joe

    2016-09-01

    Squalene synthase catalyzes the first committed step in sterol biosynthesis and consists of both an amino-terminal catalytic domain and a carboxy-terminal domain tethering the enzyme to the ER membrane. While the overall architecture of this enzyme is identical in eukaryotes, it was previously shown that plant and animal genes cannot complement a squalene synthase knockout mutation in yeast unless the carboxy-terminal domain is swapped for one of fungal origin. This implied a unique component of the fungal carboxy-terminal domain was responsible for the complementation phenotype. To identify this motif, we used Saccharomyces cerevisiae with a squalene synthase knockout mutation, and expressed intact and chimeric squalene synthases originating from fungi, plants, and animals. In contrast to previous observations, all enzymes tested could partially complement the knockout mutation when the genes were weakly expressed. However, when highly expressed, non-fungal squalene synthases could not complement the yeast mutation and instead led to the accumulation of a toxic intermediate(s) as defined by mutations of genes downstream in the ergosterol pathway. Restoration of the complete complementation phenotype was mapped to a 26-amino acid hinge region linking the catalytic and membrane-spanning domains specific to fungal squalene synthases. Over-expression of the C-terminal domain containing a hinge domain from fungi, not from animals or plants, led to growth inhibition of wild-type yeast. Because this hinge region is unique to and highly conserved within each kingdom of life, the data suggests that the hinge domain plays an essential functional role, such as assembly of ergosterol multi-enzyme complexes in fungi. PMID:27320012

  1. Twisting and subunit rotation in single FOF1-ATP synthase

    PubMed Central

    Sielaff, Hendrik; Börsch, Michael

    2013-01-01

    FOF1-ATP synthases are ubiquitous proton- or ion-powered membrane enzymes providing ATP for all kinds of cellular processes. The mechanochemistry of catalysis is driven by two rotary nanomotors coupled within the enzyme. Their different step sizes have been observed by single-molecule microscopy including videomicroscopy of fluctuating nanobeads attached to single enzymes and single-molecule Förster resonance energy transfer. Here we review recent developments of approaches to monitor the step size of subunit rotation and the transient elastic energy storage mechanism in single FOF1-ATP synthases. PMID:23267178

  2. Exploiting the Biosynthetic Potential of Type III Polyketide Synthases.

    PubMed

    Lim, Yan Ping; Go, Maybelle K; Yew, Wen Shan

    2016-01-01

    Polyketides are structurally and functionally diverse secondary metabolites that are biosynthesized by polyketide synthases (PKSs) using acyl-CoA precursors. Recent studies in the engineering and structural characterization of PKSs have facilitated the use of target enzymes as biocatalysts to produce novel functionally optimized polyketides. These compounds may serve as potential drug leads. This review summarizes the insights gained from research on type III PKSs, from the discovery of chalcone synthase in plants to novel PKSs in bacteria and fungi. To date, at least 15 families of type III PKSs have been characterized, highlighting the utility of PKSs in the development of natural product libraries for therapeutic development. PMID:27338328

  3. Analysis of the cercosporin polyketide synthase CTB1 reveals a new fungal thioesterase function

    PubMed Central

    Newman, Adam G.; Vagstad, Anna L.; Belecki, Katherine; Scheerer, Jonathan R.

    2012-01-01

    The polyketide synthase CTB1 is demonstrated to catalyze pyrone formation thereby expanding the known biosynthetic repertoire of thioesterase domains in iterative, non-reducing polyketide synthases. PMID:23108075

  4. Superconductor coil geometry and ac losses

    NASA Technical Reports Server (NTRS)

    Pierce, T. V., Jr.; Zapata, R. N.

    1976-01-01

    An empirical relation is presented which allows simple computation of volume-averaged winding fields from central fields for coils of small rectangular cross sections. This relation suggests that, in certain applications, ac-loss minimization can be accomplished by use of low winding densities, provided that hysteresis losses are independent of winding density. The ac-loss measurements on coils wound of twisted multifilamentary composite superconductors show no significant dependence on ac losses on winding density, thus permitting the use of winding density as an independent design parameter in loss minimization.

  5. Circulating Fatty Acid Synthase in pregnant women: Relationship to blood pressure, maternal metabolism and newborn parameters

    PubMed Central

    Carreras-Badosa, Gemma; Prats-Puig, Anna; Puig, Teresa; Vázquez-Ruíz, Montserrat; Bruel, Monserrat; Mendoza, Ericka; de Zegher, Francis; Ibáñez, Lourdes; López-Bermejo, Abel; Bassols, Judit

    2016-01-01

    The enzyme FASN (fatty acid synthase) is potentially related with hypertension and metabolic dysfunction. FASN is highly expressed in the human placenta. We aimed to investigate the relationship circulating FASN has with blood pressure, maternal metabolism and newborn parameters in healthy pregnant women. Circulating FASN was assessed in 115 asymptomatic pregnant women in the second trimester of gestation along with C-peptide, fasting glucose and insulin, post-load glucose lipids, HMW-adiponectin and blood pressure (the latter was assessed in each trimester of gestation). At birth, newborns and placentas were weighed. FASN expression was also able to be assessed in 80 placentas. Higher circulating FASN was associated with lower systolic blood pressure (SBP), with a more favourable metabolic phenotype (lower fasting glucose and insulin, post load glucose, HbAc1, HOMA-IR and C-peptide), and with lower placental and birth weight (all p < 0.05 to p < 0.001). Placental FASN expression related positively to circulating FASN (p < 0.005) and negatively to placental weight (p < 0.05). Our observations suggest a physiological role of placental FASN in human pregnancy. Future studies will clarify whether circulating FASN of placental origin does actually regulate placental and fetal growth, and (thereby) has a favourable influence on the pregnant mother’s insulin sensitivity and blood pressure. PMID:27090298

  6. P300 acetyltransferase regulates fatty acid synthase expression, lipid metabolism and prostate cancer growth.

    PubMed

    Gang, Xiaokun; Yang, Yinhui; Zhong, Jian; Jiang, Kui; Pan, Yunqian; Karnes, R Jeffrey; Zhang, Jun; Xu, Wanhai; Wang, Guixia; Huang, Haojie

    2016-03-22

    De novo fatty acid (FA) synthesis is required for prostate cancer (PCa) survival and progression. As a key enzyme for FA synthesis fatty acid synthase (FASN) is often overexpressed in human prostate cancers and its expression correlates with worse prognosis and poor survival. P300 is an acetyltransferase that acts as a transcription co-activator. Increasing evidence suggests that P300 is a major PCa promoter, although the underlying mechanism remains poorly understood. Here, we demonstrated that P300 binds to and increases histone H3 lysine 27 acetylation (H3K27Ac) in the FASN gene promoter. We provided evidence that P300 transcriptionally upregulates FASN expression and promotes lipid accumulation in human PCa cells in culture and Pten knockout prostate tumors in mice. Pharmacological inhibition of P300 decreased FASN expression and lipid droplet accumulation in PCa cells. Immunohistochemistry analysis revealed that expression of P300 protein positively correlates with FASN protein levels in a cohort of human PCa specimens. We further showed that FASN is a key mediator of P300-induced growth of PCa cells in culture and in mice. Together, our findings demonstrate P300 as a key factor that regulates FASN expression, lipid accumulation and cell growth in PCa. They also suggest that this regulatory pathway can serve as a new therapeutic target for PCa treatment. PMID:26934656

  7. P300 acetyltransferase regulates fatty acid synthase expression, lipid metabolism and prostate cancer growth

    PubMed Central

    Zhong, Jian; Jiang, Kui; Pan, Yunqian; Karnes, R. Jeffrey; Zhang, Jun; Xu, Wanhai; Wang, Guixia; Huang, Haojie

    2016-01-01

    De novo fatty acid (FA) synthesis is required for prostate cancer (PCa) survival and progression. As a key enzyme for FA synthesis fatty acid synthase (FASN) is often overexpressed in human prostate cancers and its expression correlates with worse prognosis and poor survival. P300 is an acetyltransferase that acts as a transcription co-activator. Increasing evidence suggests that P300 is a major PCa promoter, although the underlying mechanism remains poorly understood. Here, we demonstrated that P300 binds to and increases histone H3 lysine 27 acetylation (H3K27Ac) in the FASN gene promoter. We provided evidence that P300 transcriptionally upregulates FASN expression and promotes lipid accumulation in human PCa cells in culture and Pten knockout prostate tumors in mice. Pharmacological inhibition of P300 decreased FASN expression and lipid droplet accumulation in PCa cells. Immunohistochemistry analysis revealed that expression of P300 protein positively correlates with FASN protein levels in a cohort of human PCa specimens. We further showed that FASN is a key mediator of P300-induced growth of PCa cells in culture and in mice. Together, our findings demonstrate P300 as a key factor that regulates FASN expression, lipid accumulation and cell growth in PCa. They also suggest that this regulatory pathway can serve as a new therapeutic target for PCa treatment. PMID:26934656

  8. Identification of a cryptic type III polyketide synthase (1,3,6,8-tetrahydroxynaphthalene synthase) from Streptomyces peucetius ATCC 27952.

    PubMed

    Ghimire, Gopal Prasad; Oh, Tae-Jin; Liou, Kwangkyoung; Sohng, Jae Kyung

    2008-10-31

    We identified a 1,134-bp putative type III polyketide synthase from the sequence analysis of Streptomyces peucetius ATCC 27952, named Sp-RppA, which is characterized as 1,3,6,8-tetrahydroxynaphthalene synthase and shares 33% identity with SCO1206 from S. coelicolor A3(2) and 32% identity with RppA from S. griseus. The 1,3,6,8-tetrahydroxynaphthalene synthase is known to catalyze the sequential decarboxylative condensation, intramolecular cyclization, and aromatization of an oligoketide derived from five units of malonyl-CoA to give 1,3,6,8-tetrahydroxynaphthalene, which spontaneously oxidizes to form 2,5,7-trihydroxy-1,4-naphthoquinone (flaviolin). In this study, we report the in vivo expression and in vitro synthesis of flaviolin from purified gene product (Sp-RppA). PMID:18612244

  9. Benzophenone Synthase and Chalcone Synthase Accumulate in the Mesophyll of Hypericum perforatum Leaves at Different Developmental Stages.

    PubMed

    Belkheir, Asma K; Gaid, Mariam; Liu, Benye; Hänsch, Robert; Beerhues, Ludger

    2016-01-01

    The active medicinal constituents in Hypericum perforatum, used to treat depression and skin irritation, include flavonoids and xanthones. The carbon skeletons of these compounds are formed by chalcone synthase (CHS) and benzophenone synthase (BPS), respectively. Polyclonal antisera were raised against the polyketide synthases from Hypericum androsaemum and their IgG fractions were isolated. Immunoblotting and immunotitration were used to test the IgGs for crossreactivity and monospecificity in H. perforatum leaf protein extract. Immunofluorescence localization revealed that both CHS and BPS are located in the mesophyll. The maximum fluorescence levels were observed in approx. 0.5 and 1 cm long leaves, respectively. The fluorescence intensity observed for CHS significantly exceeded that for BPS. Using histochemical staining, flavonoids were detected in the mesophyll, indicating that the sites of biosynthesis and accumulation coincide. Our results help understand the biosynthesis and underlying regulation of active H. perforatum constituents. PMID:27446151

  10. Benzophenone Synthase and Chalcone Synthase Accumulate in the Mesophyll of Hypericum perforatum Leaves at Different Developmental Stages

    PubMed Central

    Belkheir, Asma K.; Gaid, Mariam; Liu, Benye; Hänsch, Robert; Beerhues, Ludger

    2016-01-01

    The active medicinal constituents in Hypericum perforatum, used to treat depression and skin irritation, include flavonoids and xanthones. The carbon skeletons of these compounds are formed by chalcone synthase (CHS) and benzophenone synthase (BPS), respectively. Polyclonal antisera were raised against the polyketide synthases from Hypericum androsaemum and their IgG fractions were isolated. Immunoblotting and immunotitration were used to test the IgGs for crossreactivity and monospecificity in H. perforatum leaf protein extract. Immunofluorescence localization revealed that both CHS and BPS are located in the mesophyll. The maximum fluorescence levels were observed in approx. 0.5 and 1 cm long leaves, respectively. The fluorescence intensity observed for CHS significantly exceeded that for BPS. Using histochemical staining, flavonoids were detected in the mesophyll, indicating that the sites of biosynthesis and accumulation coincide. Our results help understand the biosynthesis and underlying regulation of active H. perforatum constituents. PMID:27446151

  11. Three phase AC motor controller

    DOEpatents

    Vuckovich, Michael; Wright, Maynard K.; Burkett, John P.

    1984-03-20

    A motor controller for a three phase AC motor (10) which is adapted to operate bidirectionally from signals received either from a computer (30) or a manual control (32). The controller is comprised of digital logic circuit means which implement a forward and reverse command signal channel (27, 29) for the application of power through the forward and reverse power switching relays (16, 18, 20, 22). The digital logic elements are cross coupled to prevent activation of both channels simultaneously and each includes a plugging circuit (65, 67) for stopping the motor upon the removal of control signal applied to one of the two channels (27, 29) for a direction of rotation desired. Each plugging circuit (65, 67) includes a one-shot pulse signal generator (88, 102) which outputs a single pulse signal of predetermined pulsewidth which is adapted to inhibit further operation of the application of power in the channel which is being activated and to apply a reversal command signal to the other channel which provides a reversed phase application of power to the motor for a period defined by the pulse-width output of the one-shot signal generator to plug the motor (10) which will then be inoperative until another rotational command signal is applied to either of the two channels.

  12. Structure and mechanism of the diterpene cyclase ent-copalyl diphosphate synthase

    SciTech Connect

    Köksal, Mustafa; Hu, Huayou; Coates, Robert M.; Peters, Reuben J.; Christianson, David W.

    2011-09-20

    The structure of ent-copalyl diphosphate synthase reveals three {alpha}-helical domains ({alpha}, {beta} and {gamma}), as also observed in the related diterpene cyclase taxadiene synthase. However, active sites are located at the interface of the {beta}{gamma} domains in ent-copalyl diphosphate synthase but exclusively in the {alpha} domain of taxadiene synthase. Modular domain architecture in plant diterpene cyclases enables the evolution of alternative active sites and chemical strategies for catalyzing isoprenoid cyclization reactions.

  13. Loop residues and catalysis in OMP synthase.

    PubMed

    Wang, Gary P; Hansen, Michael Riis; Grubmeyer, Charles

    2012-06-01

    Residue-to-alanine mutations and a two-amino acid deletion have been made in the highly conserved catalytic loop (residues 100-109) of Salmonella typhimurium OMP synthase (orotate phosphoribosyltransferase, EC 2.4.2.10). As described previously, the K103A mutant enzyme exhibited a 10(4)-fold decrease in k(cat)/K(M) for PRPP; the K100A enzyme suffered a 50-fold decrease. Alanine mutations at His105 and Glu107 produced 40- and 7-fold decreases in k(cat)/K(M), respectively, and E101A, D104A, and G106A were slightly faster than the wild-type (WT) in terms of k(cat), with minor effects on k(cat)/K(M). Equilibrium binding of OMP or PRPP in binary complexes was affected little by loop mutation, suggesting that the energetics of ground-state binding have little contribution from the catalytic loop, or that a favorable binding energy is offset by costs of loop reorganization. Pre-steady-state kinetics for mutants showed that K103A and E107A had lost the burst of product formation in each direction that indicated rapid on-enzyme chemistry for WT, but that the burst was retained by H105A. Δ102Δ106, a loop-shortened enzyme with Ala102 and Gly106 deleted, showed a 10(4)-fold reduction of k(cat) but almost unaltered K(D) values for all four substrate molecules. The 20% (i.e., 1.20) intrinsic [1'-(3)H]OMP kinetic isotope effect (KIE) for WT is masked because of high forward and reverse commitment factors. K103A failed to express intrinsic KIEs fully (1.095 ± 0.013). In contrast, H105A, which has a smaller catalytic lesion, gave a [1'-(3)H]OMP KIE of 1.21 ± 0.0005, and E107A (1.179 ± 0.0049) also gave high values. These results are interpreted in the context of the X-ray structure of the complete substrate complex for the enzyme [Grubmeyer, C., Hansen, M. R., Fedorov, A. A., and Almo, S. C. (2012) Biochemistry 51 (preceding paper in this issue, DOI 10.1021/bi300083p )]. The full expression of KIEs by H105A and E107A may result from a less secure closure of the catalytic loop

  14. Natural variation in monoterpene synthesis in kiwifruit: transcriptional regulation of terpene synthases by NAC and ETHYLENE-INSENSITIVE3-like transcription factors.

    PubMed

    Nieuwenhuizen, Niels J; Chen, Xiuyin; Wang, Mindy Y; Matich, Adam J; Perez, Ramon Lopez; Allan, Andrew C; Green, Sol A; Atkinson, Ross G

    2015-04-01

    Two kiwifruit (Actinidia) species with contrasting terpene profiles were compared to understand the regulation of fruit monoterpene production. High rates of terpinolene production in ripe Actinidia arguta fruit were correlated with increasing gene and protein expression of A. arguta terpene synthase1 (AaTPS1) and correlated with an increase in transcript levels of the 2-C-methyl-D-erythritol 4-phosphate pathway enzyme 1-deoxy-D-xylulose-5-phosphate synthase (DXS). Actinidia chinensis terpene synthase1 (AcTPS1) was identified as part of an array of eight tandemly duplicated genes, and AcTPS1 expression and terpene production were observed only at low levels in developing fruit. Transient overexpression of DXS in Nicotiana benthamiana leaves elevated monoterpene synthesis by AaTPS1 more than 100-fold, indicating that DXS is likely to be the key step in regulating 2-C-methyl-D-erythritol 4-phosphate substrate flux in kiwifruit. Comparative promoter analysis identified potential NAC (for no apical meristem [NAM], Arabidopsis transcription activation factor [ATAF], and cup-shaped cotyledon [CUC])-domain transcription factor) and ETHYLENE-INSENSITIVE3-like transcription factor (TF) binding sites in the AaTPS1 promoter, and cloned members of both TF classes were able to activate the AaTPS1 promoter in transient assays. Electrophoretic mobility shift assays showed that AaNAC2, AaNAC3, and AaNAC4 bind a 28-bp fragment of the proximal NAC binding site in the AaTPS1 promoter but not the A. chinensis AcTPS1 promoter, where the NAC binding site was mutated. Activation could be restored by reintroducing multiple repeats of the 12-bp NAC core-binding motif. The absence of NAC transcriptional activation in ripe A. chinensis fruit can account for the low accumulation of AcTPS1 transcript, protein, and monoterpene volatiles in this species. These results indicate the importance of NAC TFs in controlling monoterpene production and other traits in ripening fruits. PMID:25649633

  15. Genetic Construction of Truncated and Chimeric Metalloproteins Derived from the Alpha Subunit of Acetyl-CoA Synthase from Clostridium thermoaceticum

    SciTech Connect

    Huay-Keng Loke; Xiangshi Tan; Paul A. Lindahl

    2002-06-28

    In this study, a genetics-based method is used to truncate acetyl-coenzyme A synthase from Clostridium thermoaceticum (ACS), an alpha2beta2 tetrameric 310 kda bifunctional enzyme. ACS catalyzes the reversible reduction of CO2 to CO and the synthesis of acetyl-CoA from CO (or CO2 in the presence of low-potential reductants), CoA, and a methyl group bound to a corrinoid-iron sulfur protein (CoFeSP). ACS contains 7 metal-sulfur clusters of 4 different types called A, B, C, and D. The B, C, and D clusters are located in the 72 kda beta subunit while the A-cluster, a Ni-X-Fe4S4 cluster that serves as the active site for acetyl-CoA synthase activity, is located in the 82 kda alpha subunit. The extent to which the essential properties of the cluster, including catalytic, redox, spectroscopic, and substrate-binding properties, were retained as ACS was progressively truncated was determined. Acetyl-CoA synthase catalytic activity remained when the entire alpha subunit was removed, as long as CO, rather than CO2 and a low-potential reductant, was used as a substrate. Truncating an {approx} 30 kda region from the N-terminus of the alpha subunit yielded a 49 kda protein that lacked catalytic activity but exhibited A-cluster-like spectroscopic, redox, and CO binding properties. Further truncation afforded a 23 kda protein that lacked recognizable A-cluster properties except for UV-vis spectra typical of [Fe4S4]2+ clusters. Two chimeric proteins were constructed by fusing the gene encoding a ferredoxin from Chromatium vinosum to genes encoding the 49 kda and 82 kda fragments of the alpha subunit. The chimeric proteins exhibited EPR signals that were not the simple sum of the signals from the separate proteins, suggesting magnetic interactions between clusters. This study highlights the potential for using genetics to simplify the study of complex multi-centered metalloenzymes and to generate new complex metalloenzymes with interesting properties.

  16. Natural Variation in Monoterpene Synthesis in Kiwifruit: Transcriptional Regulation of Terpene Synthases by NAC and ETHYLENE-INSENSITIVE3-Like Transcription Factors1

    PubMed Central

    Nieuwenhuizen, Niels J.; Chen, Xiuyin; Wang, Mindy Y.; Matich, Adam J.; Perez, Ramon Lopez; Allan, Andrew C.; Green, Sol A.; Atkinson, Ross G.

    2015-01-01

    Two kiwifruit (Actinidia) species with contrasting terpene profiles were compared to understand the regulation of fruit monoterpene production. High rates of terpinolene production in ripe Actinidia arguta fruit were correlated with increasing gene and protein expression of A. arguta terpene synthase1 (AaTPS1) and correlated with an increase in transcript levels of the 2-C-methyl-d-erythritol 4-phosphate pathway enzyme 1-deoxy-d-xylulose-5-phosphate synthase (DXS). Actinidia chinensis terpene synthase1 (AcTPS1) was identified as part of an array of eight tandemly duplicated genes, and AcTPS1 expression and terpene production were observed only at low levels in developing fruit. Transient overexpression of DXS in Nicotiana benthamiana leaves elevated monoterpene synthesis by AaTPS1 more than 100-fold, indicating that DXS is likely to be the key step in regulating 2-C-methyl-d-erythritol 4-phosphate substrate flux in kiwifruit. Comparative promoter analysis identified potential NAC (for no apical meristem [NAM], Arabidopsis transcription activation factor [ATAF], and cup-shaped cotyledon [CUC])-domain transcription factor) and ETHYLENE-INSENSITIVE3-like transcription factor (TF) binding sites in the AaTPS1 promoter, and cloned members of both TF classes were able to activate the AaTPS1 promoter in transient assays. Electrophoretic mobility shift assays showed that AaNAC2, AaNAC3, and AaNAC4 bind a 28-bp fragment of the proximal NAC binding site in the AaTPS1 promoter but not the A. chinensis AcTPS1 promoter, where the NAC binding site was mutated. Activation could be restored by reintroducing multiple repeats of the 12-bp NAC core-binding motif. The absence of NAC transcriptional activation in ripe A. chinensis fruit can account for the low accumulation of AcTPS1 transcript, protein, and monoterpene volatiles in this species. These results indicate the importance of NAC TFs in controlling monoterpene production and other traits in ripening fruits. PMID:25649633

  17. SUGARBEET ROOT SUCROSE SYNTHASE ISOFORMS DIFFER IN DEVELOPMENTAL EXPRESSION, SUBUNIT COMPOSITION AND RESPONSE TO PH.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two sucrose synthase isoforms have been identified by activity stained isoelectric focused polyacrylamide electrophoresis in developing sugarbeet (Beta vulgaris L.) root. Sucrose synthase isoform I (SuSyI) was present from the early stages of development to maturity. Sucrose synthase isoform II (S...

  18. Tevatron optics measurements using an AC dipole

    SciTech Connect

    Miyamoto, R.; Kopp, S.E.; Jansson, A.; Syphers, M.J.; /Fermilab

    2007-06-01

    The AC dipole is a device to study beam optics of hadron synchrotrons. It can produce sustained large amplitude oscillations with virtually no emittance growth. A vertical AC dipole for the Tevatron is recently implemented and a maximum oscillation amplitude of 2{sigma} (4{sigma}) at 980 GeV (150 GeV) is achieved [1]. When such large oscillations are measured with the BPM system of the Tevatron (20 {micro}m resolution), not only linear but even nonlinear optics can be directly measured. This paper shows how to measure {beta} function using an AC dipole and the result is compared to the other measurement. The paper also shows a test to detect optics changes when small changes are made in the Tevatron. Since an AC dipole is nondestructive, it allows frequent measurements of the optics which is necessary for such an test.

  19. The AC-120: The advanced commercial transport

    NASA Technical Reports Server (NTRS)

    Duran, David; Griffin, Ernest; Mendoza, Saul; Nguyen, Son; Pickett, Tim; Noernberg, Clemm

    1993-01-01

    The main objective of this design was to fulfill a need for a new airplane to replace the aging 100 to 150 passenger, 1500 nautical mile range aircraft such as the Douglas DC9 and Boeing 737-100 airplanes. After researching the future aircraft market, conducting extensive trade studies, and analysis on different configurations, the AC-120 Advanced Commercial Transport final design was achieved. The AC-120's main design features include the incorporation of a three lifting surface configuration which is powered by two turboprop engines. The AC-120 is an economically sensitive aircraft which meets the new FM Stage Three noise requirements, and has lower NO(x) emissions than current turbofan powered airplanes. The AC-120 also improves on its contemporaries in passenger comfort, manufacturing, and operating cost.

  20. New ACS Guidelines Approved by CPT

    NASA Astrophysics Data System (ADS)

    Polik, William F.; Larive, Cynthia K.

    2008-04-01

    The American Chemical Society (ACS) Guidelines for Bachelor's Degree Programs have been revised in 2008 by the Committee on Professional Training (CPT) to reflect changes that are occurring in the chemistry profession and chemistry education. The goals of these changes are to promote modern and innovative chemistry curricula, encourage pedagogical innovation that enhances student learning and success, define faculty and infrastructure attributes of excellent chemistry programs, and streamline the procedures for program approval and review by ACS. The curriculum guidelines for an ACS-certified bachelor's degree are described in terms of foundation coursework, in-depth coursework, and laboratory requirements. Chemistry departments are encouraged to develop degree tracks to target emerging areas of interest within chemistry. The importance of developing student skills and regular program self-evaluation is emphasized. Finally, the procedures for approving and reviewing chemistry programs by ACS are summarized.

  1. An active site-tail interaction in the structure of hexahistidine-tagged Thermoplasma acidophilum citrate synthase.

    PubMed

    Murphy, Jesse R; Donini, Stefano; Kappock, T Joseph

    2015-10-01

    Citrate synthase (CS) plays a central metabolic role in aerobes and many other organisms. The CS reaction comprises two half-reactions: a Claisen aldol condensation of acetyl-CoA (AcCoA) and oxaloacetate (OAA) that forms citryl-CoA (CitCoA), and CitCoA hydrolysis. Protein conformational changes that `close' the active site play an important role in the assembly of a catalytically competent condensation active site. CS from the thermoacidophile Thermoplasma acidophilum (TpCS) possesses an endogenous Trp fluorophore that can be used to monitor the condensation reaction. The 2.2 Å resolution crystal structure of TpCS fused to a C-terminal hexahistidine tag (TpCSH6) reported here is an `open' structure that, when compared with several liganded TpCS structures, helps to define a complete path for active-site closure. One active site in each dimer binds a neighboring His tag, the first nonsubstrate ligand known to occupy both the AcCoA and OAA binding sites. Solution data collectively suggest that this fortuitous interaction is stabilized by the crystalline lattice. As a polar but almost neutral ligand, the active site-tail interaction provides a new starting point for the design of bisubstrate-analog inhibitors of CS. PMID:26457521

  2. X-ray Crystallographic Studies of Substrate Binding to Aristolochene Synthase Suggest a Metal Ion Binding Sequence for Catalysis

    SciTech Connect

    Shishova,E.; Yu, F.; Miller, D.; Faraldos, J.; Zhao, Y.; Coates, R.; Allemann, R.; Cane, D.; Christianson, D.

    2008-01-01

    The universal sesquiterpene precursor, farnesyl diphosphate (FPP), is cyclized in an Mg2+-dependent reaction catalyzed by the tetrameric aristolochene synthase from Aspergillus terreus to form the bicyclic hydrocarbon aristolochene and a pyrophosphate anion (PPi) coproduct. The 2.1- Angstroms resolution crystal structure determined from crystals soaked with FPP reveals the binding of intact FPP to monomers A-C, and the binding of PPi and Mg2+B to monomer D. The 1.89- Angstroms resolution structure of the complex with 2-fluorofarnesyl diphosphate (2F-FPP) reveals 2F-FPP binding to all subunits of the tetramer, with Mg2+Baccompanying the binding of this analogue only in monomer D. All monomers adopt open activesite conformations in these complexes, but slight structural changes in monomers C and D of each complex reflect the very initial stages of a conformational transition to the closed state. Finally, the 2.4- Angstroms resolution structure of the complex with 12,13-difluorofarnesyl diphosphate (DF-FPP) reveals the binding of intact DF-FPP to monomers A-C in the open conformation and the binding of PPi, Mg2+B, and Mg2+C to monomer D in a predominantly closed conformation. Taken together, these structures provide 12 independent 'snapshots' of substrate or product complexes that suggest a possible sequence for metal ion binding and conformational changes required for catalysis.

  3. An active site–tail interaction in the structure of hexahistidine-tagged Thermoplasma acidophilum citrate synthase

    PubMed Central

    Murphy, Jesse R.; Donini, Stefano; Kappock, T. Joseph

    2015-01-01

    Citrate synthase (CS) plays a central metabolic role in aerobes and many other organisms. The CS reaction comprises two half-reactions: a Claisen aldol condensation of acetyl-CoA (AcCoA) and oxaloacetate (OAA) that forms citryl-CoA (CitCoA), and CitCoA hydrolysis. Protein conformational changes that ‘close’ the active site play an important role in the assembly of a catalytically competent condensation active site. CS from the thermoacidophile Thermoplasma acidophilum (TpCS) possesses an endogenous Trp fluorophore that can be used to monitor the condensation reaction. The 2.2 Å resolution crystal structure of TpCS fused to a C-terminal hexahistidine tag (TpCSH6) reported here is an ‘open’ structure that, when compared with several liganded TpCS structures, helps to define a complete path for active-site closure. One active site in each dimer binds a neighboring His tag, the first nonsubstrate ligand known to occupy both the AcCoA and OAA binding sites. Solution data collectively suggest that this fortuitous interaction is stabilized by the crystalline lattice. As a polar but almost neutral ligand, the active site–tail interaction provides a new starting point for the design of bisubstrate-analog inhibitors of CS. PMID:26457521

  4. Malate Synthase Activity in Cotton and Other Ungerminated Oilseeds

    PubMed Central

    Miernyk, Jan A.; Trelease, Richard N.; Choinski, John S.

    1979-01-01

    Extracts from several species and varieties of ungerminated cotton seeds plus homogenates from 18 other oilseeds (representing 11 different families) were examined for malate synthase and isocitrate lyase activity. Malate synthase activities in the various cotton seeds ranged from 35 to 129% of the units per dry seed weight found in Deltapine 16 cotton. For other oilseeds, the range was from 0.3 to 58% of Deltapine 16 cotton. Castor bean (Ricinus communis L.) had the least activity per mg dry weight (12-fold lower than the next lowest species), while Pima cotton (Gossypium barbadense L.) had the highest level (8.53 units). On a per seed basis, these values were 15 and 747 nanomoles per minute. Malate synthase activity was measurable in all seed types examined, whereas isocitrate lyase could not be detected in any of the seeds. We suggest that synthesis of malate synthase during seed development is universal among oilseeds in the absence of glyoxylate-cycle-associated isocitrate lyase activity. PMID:16660858

  5. Subcellular targeting and trafficking of nitric oxide synthases

    PubMed Central

    Oess, Stefanie; Icking, Ann; Fulton, David; Govers, Roland; Müller-Esterl, Werner

    2006-01-01

    Unlike most other endogenous messengers that are deposited in vesicles, processed on demand and/or secreted in a regulated fashion, NO (nitric oxide) is a highly active molecule that readily diffuses through cell membranes and thus cannot be stored inside the producing cell. Rather, its signalling capacity must be controlled at the levels of biosynthesis and local availability. The importance of temporal and spatial control of NO production is highlighted by the finding that differential localization of NO synthases in cardiomyocytes translates into distinct effects of NO in the heart. Thus NO synthases belong to the most tightly controlled enzymes, being regulated at transcriptional and translational levels, through co- and post-translational modifications, by substrate availability and not least via specific sorting to subcellular compartments, where they are in close proximity to their target proteins. Considerable efforts have been made to elucidate the molecular mechanisms that underlie the intracellular targeting and trafficking of NO synthases, to ultimately understand the cellular pathways controlling the formation and function of this powerful signalling molecule. In the present review, we discuss the mechanisms and triggers for subcellular routing and dynamic redistribution of NO synthases and the ensuing consequences for NO production and action. PMID:16722822

  6. Genetics Home Reference: N-acetylglutamate synthase deficiency

    MedlinePlus

    ... of reactions that occurs in liver cells. This cycle processes excess nitrogen, generated when protein is used by the body, to make a compound called urea that is excreted by the kidneys. The ... cycle. In people with N-acetylglutamate synthase deficiency , N- ...

  7. Incremental truncation of PHA synthases results in altered product specificity.

    PubMed

    Wang, Qian; Xia, Yongzhen; Chen, Quan; Qi, Qingsheng

    2012-05-10

    PHA synthase is the key enzyme involved in the biosynthesis of microbial polymers, polyhydroxyalkanoates (PHA). In this study, we created a hybrid library of PHA synthase gene with different crossover points by an incremental truncation method between the C-terminal fragments of the phaC(Cn) (phaC from Cupriavidus necator) and the N-terminal fragments of the phaC1(Pa) (phaC from Pseudomonas aeruginosa). As the truncation of the hybrid enzyme increased, the in vivo PHB synthesis ability of the hybrids declined gradually. PHA synthase PhaC(Cn) with a deletion on N-terminal up to 83 amino acid residues showed no synthase activity. While with the removal of up to 270 amino acids from the N-terminus, the activity of the truncated PhaC(Cn) could be complemented by the N-terminus of PhaC1(Pa). Three of the hybrid enzymes W188, W235 and W272 (named by the deleted nucleic acid number) were found to have altered product specificities. PMID:22500895

  8. Polyhydroyxalkanoate synthase fusions as a strategy for oriented enzyme immobilisation.

    PubMed

    Hooks, David O; Venning-Slater, Mark; Du, Jinping; Rehm, Bernd H A

    2014-01-01

    Polyhydroxyalkanoate (PHA) is a carbon storage polymer produced by certain bacteria in unbalanced nutrient conditions. The PHA forms spherical inclusions surrounded by granule associate proteins including the PHA synthase (PhaC). Recently, the intracellular formation of PHA granules with covalently attached synthase from Ralstonia eutropha has been exploited as a novel strategy for oriented enzyme immobilisation. Fusing the enzyme of interest to PHA synthase results in a bifunctional protein able to produce PHA granules and immobilise the active enzyme of choice to the granule surface. Functionalised PHA granules can be isolated from the bacterial hosts, such as Escherichia coli, and maintain enzymatic activity in a wide variety of assay conditions. This approach to oriented enzyme immobilisation has produced higher enzyme activities and product levels than non-oriented immobilisation techniques such as protein inclusion based particles. Here, enzyme immobilisation via PHA synthase fusion is reviewed in terms of the genetic designs, the choices of enzymes, the control of enzyme orientations, as well as their current and potential applications. PMID:24962396

  9. A geraniol-synthase gene from Cinnamomum tenuipilum.

    PubMed

    Yang, Tao; Li, Jing; Wang, Hao-Xin; Zeng, Ying

    2005-02-01

    Geraniol may accumulate up to 86-98% of the leaf essential oils in geraniol chemotypes of the evergreen camphor tree Cinnamomum tenuipilum. A similarity-based cloning strategy yielded a cDNA clone that appeared to encode a terpene synthase and which could be phylogenetically grouped within the angiosperm monoterpene synthase/subfamily. After its expression in Escherichia coli and enzyme assay with prenyl diphosphates as substrates, the enzyme encoded by the putative C. tenuipilum monoterpene synthase gene was shown to specifically convert geranyl diphosphate to geraniol as a single product by GC-MS analysis. Biochemical characterization of the partially purified recombinant protein revealed a strong dependency for Mg2+ and Mn2+, and an apparent Michaelis constant of 55.8 microM for geranyl diphosphate. Thus, a new member of the monoterpene synthase family was identified and designated as CtGES. The genome contains a single copy of CtGES gene. Expression of CtGES was exclusively observed in the geraniol chemotype of C. tenuipilum. Furthermore, in situ hybridization analysis demonstrated that CtGES mRNA was localized in the oil cells of the leaves. PMID:15680985

  10. A particular phenotype in a girl with aldosterone synthase deficiency.

    PubMed

    Williams, Tracy A; Mulatero, Paolo; Bosio, Maurizio; Lewicka, Sabina; Palermo, Mario; Veglio, Franco; Armanini, Decio

    2004-07-01

    Aldosterone synthase deficiency (ASD) usually presents in infancy as a life-threatening electrolyte imbalance. A 4-wk-old child of unrelated parents was examined for failure to thrive and salt-wasting. Notable laboratory findings were hyperkalemia, high plasma renin, and low-normal aldosterone levels. Urinary metabolite ratios of corticosterone/18-hydroxycorticosterone and 18-hydroxycorticosterone/aldosterone were intermediate between ASD type I and type II. Sequence analysis of CYP11B2, the gene encoding aldosterone synthase (P450c11AS), revealed that the patient was a compound heterozygote carrying a previously described mutation located in exon 4 causing a premature stop codon (E255X) and a further, novel mutation in exon 5 that also causes a premature stop codon (Q272X). The patient's unaffected father was a heterozygous carrier of the E255X mutation, whereas the unaffected mother was a heterozygous carrier of the Q272X mutation. Therefore, the patient's CYP11B2 encodes two truncated forms of aldosterone synthase predicted to be inactive because they lack critical active site residues as well as the heme-binding site. This case of ASD is of particular interest because despite the apparent lack of aldosterone synthase activity, the patient displays low-normal aldosterone levels, thus raising the question of its source. PMID:15240589

  11. Abietadiene synthase from grand fir (Abies grandis). cDNA isolation, characterization, and bacterial expression of a bifunctional diterpene cyclase involved in resin acid biosynthesis.

    PubMed

    Vogel, B S; Wildung, M R; Vogel, G; Croteau, R

    1996-09-20

    (-)-Abietic acid, the principal diterpenoid resin acid of the wound-induced oleoresin secreted by grand fir (Abies grandis), is synthesized by the cyclization of geranylgeranyl diphosphate to (-)-abieta-7(8),13(14)-diene, followed by sequential three-step oxidation of the C-18 methyl group of the olefin to a carboxyl function. The enzyme catalyzing the cyclization reaction, abietadiene synthase, was purified from stems of wounded grand fir saplings and was digested with trypsin. Amino acid sequence information from the resulting peptides allowed construction of degenerate oligonucleotide primers, which amplified a 551-base pair fragment from a wound-induced stem cDNA library. This hybridization probe was then utilized to screen the wound-induced stem cDNA library, from which three cDNA clones were isolated that were functionally expressed in Escherichia coli, thereby confirming that a single protein catalyzes the complex, multistep cyclization of geranylgeranyl diphosphate to abietadiene. cDNA isolate Ac22.1, which yielded the highest expressed level of cyclase activity, was 2861 base pairs in length and encoded an 868-amino acid open reading frame that included a putative plastidial transit peptide. Deduced amino acid sequence comparison to other terpene cyclases revealed an amino-terminal region of the abietadiene synthase, which resembles those of enzymes that employ substrate double bond protonation to initiate the carbocationic reaction cascade, and a carboxyl-terminal region of the synthase, which resembles those of enzymes that employ ionization of the substrate allylic diphosphate ester function to initiate the cyclization reaction. This apparent fusion of segments of the two distinct terpenoid cyclase types is consistent with the novel mechanism of the bifunctional abietadiene synthase in catalyzing both protonation-initiated and ionization-initiated cyclization steps. PMID:8798524

  12. High rate GPS positioning , JASON altimetry and marine gravimetry : monitoring the Antarctic Circumpolar Current (ACC) through the DRAKE campaigns.

    NASA Astrophysics Data System (ADS)

    Melachroinos, S. A.; Biancale, R.; Menard, Y.; Sarrailh, M.

    2008-12-01

    The Drake campaign which took place from Jan 14, 2006 - 08 Feb, 2006 has been a very successful mission in collecting a wide range of GPS and marine gravity data all along JASON altimetry ground track n° 104. The same campaign will be repeated in 2009 along 028 and 104 JASON-2 ground track. The Drake Passage (DP) chokepoint is not only well suited geographically, as the Antarctic Circumpolar Current (ACC) is constricted to its narrowest extent of 700 km, but observations and models suggest that dynamical balances are particular effective in this area. Furthermore the space geodesy observations and their products provided from several altimetry missions (currently operating ENVISAT, JASON 1 and 2, GFO, ERS and other plannified for the future such as Altika, SWOT) require the cross comparison with independent geodetic techniques at the DP. The current experiment comprises a kinematic GPS and marine gravimetry Cal/Val geodetic approach and it aims to : validate with respect to altimetry data and surface models such a kinematic high frequency GPS technique for measuring sea state and sea surface height (SSH), compare the GPS SSH profiles with altimetry mean dynamic topography (MDT) and mean sea surface (MSS) models, give recommendations for future "offshore" Cal/Val activities on the ground tracks of altimeter satellites such as JASON-2, GFO, Altika using the GNSS technology etc. The GPS observations are collected from GPS antennas installed on a wave-rider buoy , aboard the R/V "Polarstern" and from continuous geodetic reference stations in the proximity. We also analyse problems related to the ship's attitude variations in roll, pitch and yaw and a way to correct them. We also give emphasis on the impact of the ship's acceleration profiles on the so called "squat effect" and ways to deal with it. The project will in particular benefit the GOCE mission by proposing to integrate GOCE in the ocean circulation study and validate GOCE products with our independent

  13. 21 CFR 886.4440 - AC-powered magnet.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false AC-powered magnet. 886.4440 Section 886.4440 Food... DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4440 AC-powered magnet. (a) Identification. An AC-powered magnet is an AC-powered device that generates a magnetic field intended to find and...

  14. 21 CFR 886.4440 - AC-powered magnet.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false AC-powered magnet. 886.4440 Section 886.4440 Food... DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4440 AC-powered magnet. (a) Identification. An AC-powered magnet is an AC-powered device that generates a magnetic field intended to find and...

  15. 21 CFR 886.4440 - AC-powered magnet.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false AC-powered magnet. 886.4440 Section 886.4440 Food... DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4440 AC-powered magnet. (a) Identification. An AC-powered magnet is an AC-powered device that generates a magnetic field intended to find and...

  16. 21 CFR 886.4440 - AC-powered magnet.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false AC-powered magnet. 886.4440 Section 886.4440 Food... DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4440 AC-powered magnet. (a) Identification. An AC-powered magnet is an AC-powered device that generates a magnetic field intended to find and...

  17. 21 CFR 886.4440 - AC-powered magnet.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false AC-powered magnet. 886.4440 Section 886.4440 Food... DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4440 AC-powered magnet. (a) Identification. An AC-powered magnet is an AC-powered device that generates a magnetic field intended to find and...

  18. Siro(haem)amide in Allochromatium vinosum and relevance of DsrL and DsrN, a homolog of cobyrinic acid a,c-diamide synthase, for sulphur oxidation.

    PubMed

    Lübbe, Yvonne J; Youn, Hyung-Sun; Timkovich, Russell; Dahl, Christiane

    2006-08-01

    In the purple sulphur bacterium Allochromatium vinosum, the prosthetic group of dissimilatory sulphite reductase (DsrAB) was identified as siroamide, an amidated form of the classical sirohaem. The genes dsrAB are the first two of a large cluster of genes necessary for the oxidation of sulphur globules stored intracellularly during growth on sulphide and thiosulphate. DsrN is homologous to cobyrinic acid a,c diamide synthase and may therefore catalyze glutamine-dependent amidation of sirohaem. Indeed, an A. vinosumDeltadsrN in frame deletion mutant showed a significantly reduced sulphur oxidation rate that was fully restored upon complementation with dsrN in trans. Sulphite reductase was still present in the DeltadsrN mutant. DsrL is a homolog of the small subunits of bacterial glutamate synthases and was proposed to deliver glutamine for sirohaem amidation. However, recombinant DsrL does not exhibit glutamate synthase activity nor does the gene complement a glutamate synthase-deficient Escherichia coli strain. Deletion of dsrL showed that the encoded protein is absolutely essential for sulphur oxidation in A. vinosum. PMID:16907720

  19. Inhibition of ATP Synthase by Chlorinated Adenosine Analogue

    PubMed Central

    Chen, Lisa S.; Nowak, Billie J.; Ayres, Mary L.; Krett, Nancy L.; Rosen, Steven T.; Zhang, Shuxing; Gandhi, Varsha

    2009-01-01

    8-Chloroadenosine (8-Cl-Ado) is a ribonucleoside analogue that is currently in clinical trial for chronic lymphocytic leukemia. Based on the decline in cellular ATP pool following 8-Cl-Ado treatment, we hypothesized that 8-Cl-ADP and 8-Cl-ATP may interfere with ATP synthase, a key enzyme in ATP production. Mitochondrial ATP synthase is composed of two major parts; FO intermembrane base and F1 domain, containing α and β subunits. Crystal structures of both α and β subunits that bind to the substrate, ADP, are known in tight binding (αdpβdp) and loose binding (αtpβtp) states. Molecular docking demonstrated that 8-Cl-ADP/8-Cl-ATP occupied similar binding modes as ADP/ATP in the tight and loose binding sites of ATP synthase, respectively, suggesting that the chlorinated nucleotide metabolites may be functional substrates and inhibitors of the enzyme. The computational predictions were consistent with our whole cell biochemical results. Oligomycin, an established pharmacological inhibitor of ATP synthase, decreased both ATP and 8-Cl-ATP formation from exogenous substrates, however, did not affect pyrimidine nucleoside analogue triphosphate accumulation. Synthesis of ATP from ADP was inhibited in cells loaded with 8-Cl-ATP. These biochemical studies are in consent with the computational modeling; in the αtpβtp state 8-Cl-ATP occupies similar binding as ANP, a non-hydrolyzable ATP mimic that is a known inhibitor. Similarly, in the substrate binding site (αdpβdp) 8-Cl-ATP occupies a similar position as ATP mimic ADP-BeF3 −. Collectively, our current work suggests that 8-Cl-ADP may serve as a substrate and the 8-Cl-ATP may be an inhibitor of ATP synthase. PMID:19477165

  20. Cannabidiolic-acid synthase, the chemotype-determining enzyme in the fiber-type Cannabis sativa.

    PubMed

    Taura, Futoshi; Sirikantaramas, Supaart; Shoyama, Yoshinari; Yoshikai, Kazuyoshi; Shoyama, Yukihiro; Morimoto, Satoshi

    2007-06-26

    Cannabidiolic-acid (CBDA) synthase is the enzyme that catalyzes oxidative cyclization of cannabigerolic-acid into CBDA, the dominant cannabinoid constituent of the fiber-type Cannabis sativa. We cloned a novel cDNA encoding CBDA synthase by reverse transcription and polymerase chain reactions with degenerate and gene-specific primers. Biochemical characterization of the recombinant enzyme demonstrated that CBDA synthase is a covalently flavinylated oxidase. The structural and functional properties of CBDA synthase are quite similar to those of tetrahydrocannabinolic-acid (THCA) synthase, which is responsible for the biosynthesis of THCA, the major cannabinoid in drug-type Cannabis plants. PMID:17544411

  1. Transgene silencing of sucrose synthase in alfalfa stem vascular tissue by a truncated phosphoenolpyruvate carboxylase: sucrose synthase construct

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An important role of sucrose synthase (SUS, EC 2.4.1.13) in plants is to provide UDP-glucose needed for cellulose synthesis in cell walls. We examined if over-expressing SUS in alfalfa (Medicago sativa L.) would increase cellulose content of stem cell walls. Alfalfa plants were transformed with two ...

  2. Identifying the catalytic components of cellulose synthase and the maize mixed-linkage beta-glucan synthase

    SciTech Connect

    Nicholas C Carpita

    2009-04-20

    Five specific objectives of this project are to develop strategies to identify the genes that encode the catalytic components of "mixed-linkage" (1→3),(1→4)-beta-D-glucans in grasses, to determine the protein components of the synthase complex, and determine the biochemical mechanism of synthesis. We have used proteomic approaches to define intrinsic and extrinsic polypeptides of Golgi membranes that are associated with polysaccharide synthesis and trafficking. We were successful in producing recombinant catalytic domains of cellulose synthase genes and discovered that they dimerize upon concentration, indicating that two CesA proteins form the catalytic unit. We characterized a brittle stalk2 mutant as a defect in a COBRA-like protein that results in compromised lignin-cellulose interactions that decrease tissue flexibility. We used virus-induced gene silencing of barley cell wall polysaccharide synthesis by BSMV in an attempt to silence specific members of the cellulose synthase-like gene family. However, we unexpectedly found that regardless of the specificity of the target gene, whole gene interaction networks were silenced. We discovered the cause to be an antisense transcript of the cellulose synthase gene initiated small interfering RNAs that spread silencing to related genes.

  3. Experimental AC (Asphalt Concrete) overlays of PCC pavement

    NASA Astrophysics Data System (ADS)

    Smith, R. D.

    1983-11-01

    A series of experimental asphalt concrete (AC) overlays was constructed over an existing distressed portland cement concrete pavement on Interstate 80 near Boca, California. The experimental overlays included rubberized dense-graded AC, rubberized open-graded AC, a rubber flush coat interlayer, dense-graded AC with short polyester fibers and Bituthene interlayer strips. The report presents a description and discussion of AC mix batching, construction observations, laboratory testing, overlay covering, and initial performance evaluation.

  4. The three tricarboxylate synthase activities of Corynebacterium glutamicum and increase of L-lysine synthesis.

    PubMed

    Radmacher, Eva; Eggeling, Lothar

    2007-09-01

    Corynebacterium glutamicum owns a citrate synthase and two methylcitrate synthases. Characterization of the isolated enzymes showed that the two methylcitrate synthases have comparable catalytic efficiency, k (cat)/K (m), as the citrate synthase with acetyl-CoA as substrate, although these enzymes are only synthesized during growth on propionate-containing media. Thus, the methylcitrate synthases have a relaxed substrate specifity, as also demonstrated by their activity with butyryl-CoA, whereas the citrate synthase does not accept acyl donors other than acetyl-CoA. A double mutant deleted of the citrate synthase gene gltA and one of the methylcitrate synthase genes, prpC1, was made unable to grow on glucose. From this mutant, a collection of suppressor mutants could be isolated which were demonstrated to have regained citrate synthase activity due to the relaxed specificity of the methylcitrate synthase PrpC2. Molecular characterization of these mutants showed that the regulator PrpR (Cg0800) located downstream of prpC1 is mutated with mutations likely to effect the secondary structure of the regulator, thus, resulting in expression of prpC2. This expression results in a citrate synthase activity, which is lower than that due to gltA in the original strain and results in increased L-lysine accumulation. PMID:17653710

  5. Measurement of annexin V uptake and lactadherin labeling for the quantification of apoptosis in adherent Tca8113 and ACC-2 cells.

    PubMed

    Hu, T; Shi, J; Jiao, X; Zhou, J; Yin, X

    2008-09-01

    Phosphatidylserine (PS) exposure occurs during the cell death program and fluorescein-labeled lactadherin permits the detection of PS exposure earlier than annexin V in suspended cell lines. Adherent cell lines were studied for this apoptosis-associated phenomenon to determine if PS probing methods are reliable because specific membrane damage may occur during harvesting. Apoptosis was induced in the human tongue squamous carcinoma cell line (Tca8113) and the adenoid cystic carcinoma cell line (ACC-2) by arsenic trioxide. Cells were harvested with a modified procedure and labeled with lactadherin and/or annexin V. PS exposure was localized by confocal microscopy and apoptosis was quantified by flow cytometry. The detachment procedure without trypsinization did not induce cell damage. In competition binding experiments, phospholipid vesicles competed for more than 95 and 90% of lactadherin but only about 75 and 70% of annexin V binding to Tca8113 and ACC-2 cells. These data indicate that PS exposure occurs in three stages during the cell death program and that fluorescein-labeled lactadherin permitted the detection of early PS exposure. A similar pattern of PS exposure has been observed in two malignant cell lines with different adherence, suggesting that this pattern of PS exposure is common in adherent cells. Both lactadherin and annexin V could be used in adherent Tca8113 and ACC-2 cell lines when an appropriate harvesting procedure was used. Lactadherin is more sensitive than annexin V for the detection of PS exposure as the physical structure of PS in these blebs and condensed apoptotic cell surface may be more conducive to binding lactadherin than annexin V. PMID:18820763

  6. Complete plastid genome sequence of Primula sinensis (Primulaceae): structure comparison, sequence variation and evidence for accD transfer to nucleus

    PubMed Central

    Liu, Tong-Jian; Zhang, Cai-Yun; Yan, Hai-Fei; Zhang, Lu

    2016-01-01

    Species-rich genus Primula L. is a typical plant group with which to understand genetic variance between species in different levels of relationships. Chloroplast genome sequences are used to be the information resource for quantifying this difference and reconstructing evolutionary history. In this study, we reported the complete chloroplast genome sequence of Primula sinensis and compared it with other related species. This genome of chloroplast showed a typical circular quadripartite structure with 150,859 bp in sequence length consisting of 37.2% GC base. Two inverted repeated regions (25,535 bp) were separated by a large single-copy region (82,064 bp) and a small single-copy region (17,725 bp). The genome consists of 112 genes, including 78 protein-coding genes, 30 tRNA genes and four rRNA genes. Among them, seven coding genes, seven tRNA genes and four rRNA genes have two copies due to their locations in the IR regions. The accD and infA genes lacking intact open reading frames (ORF) were identified as pseudogenes. SSR and sequence variation analyses were also performed on the plastome of Primula sinensis, comparing with another available plastome of P. poissonii. The four most variable regions, rpl36–rps8, rps16–trnQ, trnH–psbA and ndhC–trnV, were identified. Phylogenetic relationship estimates using three sub-datasets extracted from a matrix of 57 protein-coding gene sequences showed the identical result that was consistent with previous studies. A transcript found from P. sinensis transcriptome showed a high similarity to plastid accD functional region and was identified as a putative plastid transit peptide at the N-terminal region. The result strongly suggested that plastid accD has been functionally transferred to the nucleus in P. sinensis. PMID:27375965

  7. Determination of ACC-induced cell-programmed death in roots of Vicia faba ssp. minor seedlings by acridine orange and ethidium bromide staining.

    PubMed

    Byczkowska, Anna; Kunikowska, Anita; Kaźmierczak, Andrzej

    2013-02-01

    Fluorescence staining with acridine orange (AO) and ethidium bromide (EB) showed that nuclei of cortex root cells of 1-aminocyclopropane-1-carboxylic acid (ACC)-treated Vicia faba ssp. minor seedlings differed in color. Measurement of resultant fluorescence intensity (RFI) showed that it increased when the color of nuclear chromatin was changed from green to red, indicating that EB moved to the nuclei via the cell membrane which lost its integrity and stained nuclei red. AO/EB staining showed that changes in color of the nuclear chromatin were accompanied by DNA condensation, nuclei fragmentation, and chromatin degradation which were also shown after 4,6-diamidino-2-phenylindol staining. These results indicate that ACC induced programmed cell death. The increasing values of RFI together with the corresponding morphological changes of nuclear chromatin were the basis to prepare the standard curve; cells with green unchanged nuclear chromatin were alive while those with dark orange and bright red nuclei were dead. The cells with nuclei with green-yellow, yellow-orange, and bright orange chromatin with or without their condensation and fragmentation chromatin were dying. The prepared curve has became the basis to draw up the digital method for detection and determination of the number of living, dying, and dead cells in an in planta system and revealed that ACC induced death in about 20% of root cortex cells. This process was accompanied by increase in ion leakage, shortening of cells and whole roots, as well as by increase in weight and width of the apical part of roots and appearance of few aerenchymatic spaces while not by internucleosomal DNA degradation. PMID:22350735

  8. Enhancement of heavy metal accumulation by tissue specific co-expression of iaaM and ACC deaminase genes in plants.

    PubMed

    Zhang, Yong; Zhao, Lihong; Wang, Yao; Yang, Baoyu; Chen, Shiyun

    2008-06-01

    1-Aminocyclopropane deaminase (ACC) and tryptophan monooxygenase are two enzymes involved in plant senescence-inhibiting and growth-promoting regulation, respectively. In this study, two binary vectors were constructed in which the Agrobacterium iaaM gene was under the transcriptional control of a xylem-specific glycine-rich protein promoter alone, or co-expressed with the bacterial ACC deaminase gene, which was driven by the constitutive CaMV 35S promoter. Transgenic petunia shoots co-expressing both genes were able to root on medium supplemented with 7.5 mg l(-1) CoCl2. When T1 transgenic tobacco plants were grown in sand supplemented with Cu2+ and Co2+, tissue specific co-expression of both iaaM and ACC deaminase genes showed faster growth with larger biomass with a more extensive root system, and accumulated a greater amount of heavy metals than the empty vector control plants. When T1 transgenic tobacco plants were grown in soil watered with different concentrations of CuSO4, xylem specific expression of the iaaM gene caused the accumulation of more Cu2+ than the empty vector control at lower CuSO4 concentrations, but showed severe toxic symptoms at concentration of 100 mg l(-1) CuSO4. T1 transgenic plants co-expressing both genes accumulated more heavy metals into the plant shoots and can tolerate CuSO4 at 150 mg l(-1). In addition, plants co-expressing these two genes can grow well in a complex contaminated soil containing both inorganic and organic pollutants, while the growth of the control plants was greatly inhibited. PMID:18471863

  9. Characterization of ethylene biosynthesis associated with ripening in banana fruit.

    PubMed

    Liu, X; Shiomi, S; Nakatsuka, A; Kubo, Y; Nakamura, R; Inaba, A

    1999-12-01

    We investigated the characteristics of ethylene biosynthesis associated with ripening in banana (Musa sp. [AAA group, Cavendish subgroup] cv Grand Nain) fruit. MA-ACS1 encoding 1-aminocyclopropane-1-carboxylic acid (ACC) synthase in banana fruit was the gene related to the ripening process and was inducible by exogenous ethylene. At the onset of the climacteric period in naturally ripened fruit, ethylene production increased greatly, with a sharp peak concomitant with an increase in the accumulation of MA-ACS1 mRNA, and then decreased rapidly. At the onset of ripening, the in vivo ACC oxidase activity was enhanced greatly, followed by an immediate and rapid decrease. Expression of the MA-ACO1 gene encoding banana ACC oxidase was detectable at the preclimacteric stage, increased when ripening commenced, and then remained high throughout the later ripening stage despite of a rapid reduction in the ACC oxidase activity. This discrepancy between enzyme activity and gene expression of ACC oxidase could be, at least in part, due to reduced contents of ascorbate and iron, cofactors for the enzyme, during ripening. Addition of these cofactors to the incubation medium greatly stimulated the in vivo ACC oxidase activity during late ripening stages. The results suggest that ethylene production in banana fruit is regulated by transcription of MA-ACS1 until climacteric rise and by reduction of ACC oxidase activity possibly through limited in situ availability of its cofactors once ripening has commenced, which in turn characterizes the sharp peak of ethylene production. PMID:10594112

  10. Characterization of Ethylene Biosynthesis Associated with Ripening in Banana Fruit1

    PubMed Central

    Liu, Xuejun; Shiomi, Shinjiro; Nakatsuka, Akira; Kubo, Yasutaka; Nakamura, Reinosuke; Inaba, Akitsugu

    1999-01-01

    We investigated the characteristics of ethylene biosynthesis associated with ripening in banana (Musa sp. [AAA group, Cavendish subgroup] cv Grand Nain) fruit. MA-ACS1 encoding 1-aminocyclopropane-1-carboxylic acid (ACC) synthase in banana fruit was the gene related to the ripening process and was inducible by exogenous ethylene. At the onset of the climacteric period in naturally ripened fruit, ethylene production increased greatly, with a sharp peak concomitant with an increase in the accumulation of MA-ACS1 mRNA, and then decreased rapidly. At the onset of ripening, the in vivo ACC oxidase activity was enhanced greatly, followed by an immediate and rapid decrease. Expression of the MA-ACO1 gene encoding banana ACC oxidase was detectable at the preclimacteric stage, increased when ripening commenced, and then remained high throughout the later ripening stage despite of a rapid reduction in the ACC oxidase activity. This discrepancy between enzyme activity and gene expression of ACC oxidase could be, at least in part, due to reduced contents of ascorbate and iron, cofactors for the enzyme, during ripening. Addition of these cofactors to the incubation medium greatly stimulated the in vivo ACC oxidase activity during late ripening stages. The results suggest that ethylene production in banana fruit is regulated by transcription of MA-ACS1 until climacteric rise and by reduction of ACC oxidase activity possibly through limited in situ availability of its cofactors once ripening has commenced, which in turn characterizes the sharp peak of ethylene production. PMID:10594112

  11. A fifth member of the tomato 1-aminocyclopropane-1-carboxylic acid (ACC) oxidase gene family harbours a leucine zipper and is anaerobically induced.

    PubMed

    Sell, Simone; Hehl, Reinhard

    2005-02-01

    Using the leucine zipper domain of a small anaerobically induced bZIP transcription factor in a yeast two hybrid screen, anaerobically induced genes were identified. One peptide corresponds to an anaerobically induced IDS4-like protein that maybe involved in G-protein signaling. Surprisingly, another interacting peptide corresponds to a novel anaerobically induced 1-aminocyclopropane-1-carboxylic acid (ACC) oxidase, designated ACO5. ACO5 harbours a leucine zipper and transcription is mainly induced in fruits and to a lesser extend in leaves. The role of ACO5 in the low oxygen response of tomato is discussed. PMID:16040352

  12. Synthesis of delta-aminolaevulinate synthase by isolated liver polyribosomes.

    PubMed Central

    Whiting, M J

    1976-01-01

    1. Postmitochondrial supernatants were prepared from the livers of chick embryos and were incubated under conditions that supported protein synthesis. delta-Aminolaevulinate synthase (EC 2.3.1.37) was synthesized by supernatants from livers treated with the porphyrinogenic drugs 2-allyl-2-isopropylacetamide and/or 3,5-diethoxycarbonyl-1,4-dihydrocollidine, but synthesis by supernatants from normal livers could not be detected. Synthesis of enzyme released from polyribosomes was measured by immunoprecipitation with specific antibody to the mitochondrial enzyme, and the specificity of the reaction was established by electrophoresis of dissociated immunoprecipitates on sodium dodecyl sulphate/polyacrylamide gels. 2. The relative synthesis of delta-aminolaevulinate synthase in vitro was comparable with that previously measured in vivo, and was correlated with the enzyme activity of the liver. 3. Enzyme synthesis in vitro occurred predominantly on free rather than membrane-bound polyribosomes. 4. The mol.wt. of the product synthesized in vitro was 7000 +/- 7000 by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. However, pulse-labelling of the enzyme in vivo confirmed its mol.wt. to be 49000 +/- 5000 when isolated from the mitochondrion. A small amount of immunoprecipitable enzyme of mol.wt. 70000 was detected in the cytosol in vivo. In chick embryo liver, delta-aminolaevulinate synthase therefore appears to be synthesized on cytoplasmic polyribosomes as a polypeptide of mol.wt. 70000, which in vivo is rapidly incorporated into the mitochondrion, and is then extracted as a lower-molecular-weight form. 5. Haemin added to the postmitochondrial supernatant-containing incubation mixture at concentrations up to 10 muM had no effect on general protein synthesis or the synthesis of delta-aminolaevulinate synthase. On the other hand, haemin treatment of induced chick embryo livers in vivo for 3h markedly decreased the relative synthesis of delta

  13. Mechanism of Germacradien-4-ol Synthase-Controlled Water Capture.

    PubMed

    Grundy, Daniel J; Chen, Mengbin; González, Verónica; Leoni, Stefano; Miller, David J; Christianson, David W; Allemann, Rudolf K

    2016-04-12

    The sesquiterpene synthase germacradiene-4-ol synthase (GdolS) from Streptomyces citricolor is one of only a few known high-fidelity terpene synthases that convert farnesyl diphosphate (FDP) into a single hydroxylated product. Crystals of unliganded GdolS-E248A diffracted to 1.50 Å and revealed a typical class 1 sesquiterpene synthase fold with the active site in an open conformation. The metal binding motifs were identified as D(80)DQFD and N(218)DVRSFAQE. Some bound water molecules were evident in the X-ray crystal structure, but none were obviously positioned to quench a putative final carbocation intermediate. Incubations in H2(18)O generated labeled product, confirming that the alcohol functionality arises from nucleophilic capture of the final carbocation by water originating from solution. Site-directed mutagenesis of amino acid residues from both within the metal binding motifs and without identified by sequence alignment with aristolochene synthase from Aspergillus terreus generated mostly functional germacradien-4-ol synthases. Only GdolS-N218Q generated radically different products (∼50% germacrene A), but no direct evidence of the mechanism of incorporation of water into the active site was obtained. Fluorinated FDP analogues 2F-FDP and 15,15,15-F3-FDP were potent noncompetitive inhibitors of GdolS. 12,13-DiF-FDP generated 12,13-(E)-β-farnesene upon being incubated with GdolS, suggesting stepwise formation of the germacryl cation during the catalytic cycle. Incubation of GdolS with [1-(2)H2]FDP and (R)-[1-(2)H]FDP demonstrated that following germacryl cation formation a [1,3]-hydride shift generates the final carbocation prior to nucleophilic capture. The stereochemistry of this shift is not defined, and the deuteron in the final product was scrambled. Because no clear candidate residue for binding of a nucleophilic water molecule in the active site and no significant perturbation of product distribution from the replacement of active site residues

  14. Immunoaffinity purification and characterization of thromboxane synthase from porcine lung.

    PubMed

    Shen, R F; Tai, H H

    1986-09-01

    Thromboxane synthase has been purified 620-fold from porcine lung microsomes by a three-step purification procedure including Lubrol-PX solubilization, reactive blue-agarose chromatography, and immunoaffinity chromatography. The purified enzyme exhibited a single protein band (53,000 daltons) on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Rabbit antiserum raised against the purified enzyme immunoprecipitated thromboxane synthase activity from crude enzyme preparations of porcine lung, cow lung, and human platelets, indicating the existence of structural homology of the enzyme in these species. Immunoblotting experiment identified the same polypeptide (53,000 daltons) in porcine lung and a polypeptide of 50,000 daltons in human platelets, confirming the identity of the enzyme and the specificity of the antiserum. Purified thromboxane synthase is a hemoprotein with a Soret-like absorption peak at 418 nm. The enzyme reaction has a Km for 15-hydroxy-9 alpha, 11 alpha-peroxidoprosta-5, 13-dienoic acid of 12 microM, an optimal pH of 7.5, and an optimal temperature of reaction at 30 degrees C. Purified thromboxane synthase catalyzed the formation of both thromboxane B2 and 12-hydroxy-5,8,10-heptadecatrienoic acid (HHT). The ratios of HHT to thromboxane B2 varied from 1.6 to 2.1 dependent on the reaction conditions. Except that HHT was formed at a greater rate, the formation of HHT and that of thromboxane responded identically to pH, temperature, substrate concentration, kinetics of formation, metal ions, and inhibitors suggesting that the two products are probably formed at the same active site via a common intermediate. Thromboxane synthase was irreversibly inactivated by 15-hydroxy-9 alpha, 11 alpha-peroxidoprosta-5,13-dienoic acid during catalysis and by treatment of 15-hydroperoxyeicosatetraenoic acid. The irreversible inactivation, however, could be protected by reversible inhibitors such as sodium (E)-3-[4-(1-imidazolylmethyl)phenyl]-2-propenoate and

  15. Mechanism of Germacradien-4-ol Synthase-Controlled Water Capture

    PubMed Central

    2016-01-01

    The sesquiterpene synthase germacradiene-4-ol synthase (GdolS) from Streptomyces citricolor is one of only a few known high-fidelity terpene synthases that convert farnesyl diphosphate (FDP) into a single hydroxylated product. Crystals of unliganded GdolS-E248A diffracted to 1.50 Å and revealed a typical class 1 sesquiterpene synthase fold with the active site in an open conformation. The metal binding motifs were identified as D80DQFD and N218DVRSFAQE. Some bound water molecules were evident in the X-ray crystal structure, but none were obviously positioned to quench a putative final carbocation intermediate. Incubations in H218O generated labeled product, confirming that the alcohol functionality arises from nucleophilic capture of the final carbocation by water originating from solution. Site-directed mutagenesis of amino acid residues from both within the metal binding motifs and without identified by sequence alignment with aristolochene synthase from Aspergillus terreus generated mostly functional germacradien-4-ol synthases. Only GdolS-N218Q generated radically different products (∼50% germacrene A), but no direct evidence of the mechanism of incorporation of water into the active site was obtained. Fluorinated FDP analogues 2F-FDP and 15,15,15-F3-FDP were potent noncompetitive inhibitors of GdolS. 12,13-DiF-FDP generated 12,13-(E)-β-farnesene upon being incubated with GdolS, suggesting stepwise formation of the germacryl cation during the catalytic cycle. Incubation of GdolS with [1-2H2]FDP and (R)-[1-2H]FDP demonstrated that following germacryl cation formation a [1,3]-hydride shift generates the final carbocation prior to nucleophilic capture. The stereochemistry of this shift is not defined, and the deuteron in the final product was scrambled. Because no clear candidate residue for binding of a nucleophilic water molecule in the active site and no significant perturbation of product distribution from the replacement of active site residues were

  16. Cyclotron and linac production of Ac-225.

    PubMed

    Melville, Graeme; Allen, Barry J

    2009-04-01

    Radium needles that were once implanted into tumours as a cancer treatment are now obsolete and constitute a radioactive waste problem, as their half-life is 1600 years. The reduction of radium by photonuclear transmutation by bombarding Ra-226 with high-energy photons from a medical linear accelerator (linac) has been investigated. A linac dose of 2800 Gy produced about 2.4 MBq (64 microCi) of Ra-225, which decays to Ac-225 and can then be used for 'Targeted Alpha Therapy' (TAT) of cancer. This result, while consistent with theoretical calculations, is far too low to be of practical use unless much larger quantities of radium are irradiated. The increasing application of Ac-225 for cancer therapy indicates the potential need for its increased production and availability. This paper investigates the possibility of producing of Ac-225 in commercial quantities, which could potentially reduce obsolete radioactive material and displace the need for expensive importation of Ac-225 from the USA and Russia in the years ahead. Scaled up production of Ac-225 could theoretically be achieved by the use of a high current cyclotron or linac. Production specifications are determined for a linac in terms of current, pulse length and frequency, as well as an examination of other factors such as radiation issues and radionuclei separation. Yields are compared with those calculated for the Australian National Cyclotron in Sydney. PMID:19135381

  17. Deficiency of sphingomyelin synthase-1 but not sphingomyelin synthase-2 causes hearing impairments in mice.

    PubMed

    Lu, Mei-Hong; Takemoto, Makoto; Watanabe, Ken; Luo, Huan; Nishimura, Masataka; Yano, Masato; Tomimoto, Hidekazu; Okazaki, Toshiro; Oike, Yuichi; Song, Wen-Jie

    2012-08-15

    Sphingomyelin (SM) is a sphingolipid reported to function as a structural component of plasma membranes and to participate in signal transduction. The role of SM metabolism in the process of hearing remains controversial. Here, we examined the role of SM synthase (SMS), which is subcategorized into the family members SMS1 and SMS2, in auditory function. Measurements of auditory brainstem response (ABR) revealed hearing impairment in SMS1−/− mice in a low frequency range (4–16 kHz). As a possible mechanism of this impairment, we found that the stria vascularis (SV) in these mice exhibited atrophy and disorganized marginal cells. Consequently, SMS1−/− mice exhibited significantly smaller endocochlear potentials (EPs). As a possible mechanism for EP reduction, we found altered expression patterns and a reduced level of KCNQ1 channel protein in the SV of SMS1−/− mice. These mice also exhibited reduced levels of distortion product otoacoustic emissions. Quantitative comparison of the SV atrophy, KCNQ1 expression, and outer hair cell density at the cochlear apical and basal turns revealed no location dependence, but more macrophage invasion into the SV was observed in the apical region than the basal region, suggesting a role of cochlear location-dependent oxidative stress in producing the frequency dependence of hearing loss in SMS1−/− mice. Elevated ABR thresholds, decreased EPs, and abnormal KCNQ1 expression patterns in SMS1−/− mice were all found to be progressive with age. Mice lacking SMS2, however, exhibited neither detectable hearing loss nor changes in their EPs. Taken together, our results suggest that hearing impairments occur in SMS1−/− but not SMS2−/− mice. Defects in the SV with subsequent reductions in EPs together with hair cell dysfunction may account, at least partially, for hearing impairments in SMS1−/− mice. PMID:22641779

  18. Hematopoetic prostaglandin D synthase: an ESR1-dependent oviductal epithelial cell synthase.

    PubMed

    Bridges, Phillip J; Jeoung, Myoungkun; Shim, Sarah; Park, Ji Yeon; Lee, Jae Eun; Sapsford, Lindsay A; Trudgen, Kourtney; Ko, Chemyong; Gye, Myung Chan; Jo, Misung

    2012-04-01

    Oviductal disease is a primary cause of infertility, a problem that largely stems from excessive inflammation of this key reproductive organ. Our poor understanding of the mechanisms regulating oviductal inflammation restricts our ability to diagnose, treat, and/or prevent oviductal disease. Using mice, our objective was to determine the spatial localization, regulatory mechanism, and functional attributes of a hypothesized regulator of oviductal inflammation, the hematopoietic form of prostaglandin D synthase (HPGDS). Immunohistochemistry revealed specific localization of HPGDS to the oviduct's epithelium. In the isthmus, expression of HPGDS was consistent. In the ampulla, expression of HPGDS appeared dependent upon stage of the estrous cycle. HPGDS was expressed in the epithelium of immature and cycling mice but not in the oviducts of estrogen receptor α knockouts. Two receptor subtypes bind PGD₂: PGD₂ receptor and G protein-coupled receptor 44. Expression of mRNA for Ptgdr was higher in the epithelial cells (EPI) than in the stroma (P < 0.05), whereas mRNA for Gpr44 was higher in the stroma than epithelium (P < 0.05). Treatment of human oviductal EPI with HQL-79, an inhibitor of HPGDS, decreased cell viability (P < 0.05). Treatment of mice with HQL-79 increased mRNA for chemokine (C-C motif) ligands 3, 4, and 19; chemokine (C-X-C motif) ligands 11 and 12; IL-13 and IL-17B; and TNF receptor superfamily, member 1b (P < 0.02 for each mRNA). Overall, these results suggest that HPGDS may play a role in the regulation of inflammation and EPI health within the oviduct. PMID:22374975

  19. Phasin proteins activate Aeromonas caviae polyhydroxyalkanoate (PHA) synthase but not Ralstonia eutropha PHA synthase.

    PubMed

    Ushimaru, Kazunori; Motoda, Yoko; Numata, Keiji; Tsuge, Takeharu

    2014-05-01

    In this study, we performed in vitro and in vivo activity assays of polyhydroxyalkanoate (PHA) synthases (PhaCs) in the presence of phasin proteins (PhaPs), which revealed that PhaPs are activators of PhaC derived from Aeromonas caviae (PhaCAc). In in vitro assays, among the three PhaCs tested, PhaCAc was significantly activated when PhaPs were added at the beginning of polymerization (prepolymerization PhaCAc), whereas the prepolymerization PhaCRe (derived from Ralstonia eutropha) and PhaCDa (Delftia acidovorans) showed reduced activity with PhaPs. The PhaP-activated PhaCAc showed a slight shift of substrate preference toward 3-hydroxyhexanoyl-CoA (C6). PhaPAc also activated PhaCAc when it was added during polymerization (polymer-elongating PhaCAc), while this effect was not observed for PhaCRe. In an in vivo assay using Escherichia coli TOP10 as the host strain, the effect of PhaPAc expression on PHA synthesis by PhaCAc or PhaCRe was examined. As PhaPAc expression increased, PHA production was increased by up to 2.3-fold in the PhaCAc-expressing strain, whereas it was slightly increased in the PhaCRe-expressing strain. Taken together, this study provides evidence that PhaPs function as activators for PhaCAc both in vitro and in vivo but do not activate PhaCRe. This activating effect may be attributed to the new role of PhaPs in the polymerization reaction by PhaCAc. PMID:24584238

  20. Endothelial Nitric Oxide Synthase (-786T>C) and Endothelin-1 (5665G>T) Gene Polymorphisms as Vascular Dysfunction Risk Factors in Sickle Cell Anemia.

    PubMed

    Vilas-Boas, Wendell; Figueiredo, Camylla V B; Pitanga, Thassila N; Carvalho, Magda O S; Santiago, Rayra P; Santana, Sânzio S; Guarda, Caroline C; Zanette, Angela M D; Cerqueira, Bruno A V; Gonçalves, Marilda S

    2016-01-01

    Sickle cell anemia (SCA) patients have vascular complications, and polymorphisms in endothelin-1 (ET-1) and endothelial nitric oxide synthase (eNOS) genes were associated with ET-1 and nitric oxide disturbance. We investigate the association of ET-1 5665G>T and eNOS -786T>C polymorphisms with soluble adhesion molecules (sVCAM-1 and sICAM-1), biochemical markers, and medical history. We studied 101 SCA patients; carriers of eNOS minor allele (C) had the highest levels of sVCAM-1, and carriers of ET-1 minor allele had more occurrence of acute chest syndrome (ACS). The multivariate analysis suggested the influence of the ET-1 gene on ACS outcome and an association of the eNOS gene with upper respiratory tract infection. We suggest that eNOS and ET-1 gene polymorphisms can influence SCA pathophysiology and that eNOS variant in SCA patients might be important to nitric oxide activity and vascular alteration. We found an association of the ET-1 minor allele in ACS, showing the importance of genetic screening in SCA. PMID:27486304

  1. Novel domain arrangement in the crystal structure of a truncated acetyl-CoA synthase fromMoorella thermoacetica†‡

    PubMed Central

    Volbeda, Anne; Darnault, Claudine; Tan, Xiangshi; Lindahl, Paul A.; Fontecilla-Camps, Juan C.

    2009-01-01

    Ni-dependent Acetyl-CoA synthase (ACS) and CO dehydrogenase (CODH) constitute the central enzyme complex of the Wood-Ljungdahl pathway of acetyl-CoA formation. The crystal structure of a recombinant bacterial ACS lacking the N-terminal domain that interacts with CODH shows a large reorganization of the remaining two globular domains, producing a narrow cleft of suitable size, shape and nature to bind CoA. Sequence comparisons with homologous archaeal enzymes that naturally lack the N-terminal domain show that many amino acids lining this cleft are conserved. Besides the typical [4Fe-4S] center, the A-cluster contains only one proximal metal ion that, according to anomalous scattering data, is most likely Cu or Zn. Incorporation of a functional Ni2Fe4S4 A-cluster would require only minor structural rearrangements. Using available structures, a plausible model of the interaction between CODH and the smaller ACS in archaeal multi-enzyme complexes is presented, along with a discussion of evolutionary relationships of the archaeal and bacterial enzymes. PMID:19650626

  2. Endothelial Nitric Oxide Synthase (−786T>C) and Endothelin-1 (5665G>T) Gene Polymorphisms as Vascular Dysfunction Risk Factors in Sickle Cell Anemia

    PubMed Central

    Vilas-Boas, Wendell; Figueiredo, Camylla V. B.; Pitanga, Thassila N.; Carvalho, Magda O. S.; Santiago, Rayra P.; Santana, Sânzio S.; Guarda, Caroline C.; Zanette, Angela M. D.; Cerqueira, Bruno A. V.; Gonçalves, Marilda S.

    2016-01-01

    Sickle cell anemia (SCA) patients have vascular complications, and polymorphisms in endothelin-1 (ET-1) and endothelial nitric oxide synthase (eNOS) genes were associated with ET-1 and nitric oxide disturbance. We investigate the association of ET-1 5665G>T and eNOS −786T>C polymorphisms with soluble adhesion molecules (sVCAM-1 and sICAM-1), biochemical markers, and medical history. We studied 101 SCA patients; carriers of eNOS minor allele (C) had the highest levels of sVCAM-1, and carriers of ET-1 minor allele had more occurrence of acute chest syndrome (ACS). The multivariate analysis suggested the influence of the ET-1 gene on ACS outcome and an association of the eNOS gene with upper respiratory tract infection. We suggest that eNOS and ET-1 gene polymorphisms can influence SCA pathophysiology and that eNOS variant in SCA patients might be important to nitric oxide activity and vascular alteration. We found an association of the ET-1 minor allele in ACS, showing the importance of genetic screening in SCA. PMID:27486304

  3. ac propulsion system for an electric vehicle

    NASA Technical Reports Server (NTRS)

    Geppert, S.

    1980-01-01

    It is pointed out that dc drives will be the logical choice for current production electric vehicles (EV). However, by the mid-80's, there is a good chance that the price and reliability of suitable high-power semiconductors will allow for a competitive ac system. The driving force behind the ac approach is the induction motor, which has specific advantages relative to a dc shunt or series traction motor. These advantages would be an important factor in the case of a vehicle for which low maintenance characteristics are of primary importance. A description of an EV ac propulsion system is provided, taking into account the logic controller, the inverter, the motor, and a two-speed transmission-differential-axle assembly. The main barrier to the employment of the considered propulsion system in EV is not any technical problem, but inverter transistor cost.

  4. ACS Data Handbook v.6.0

    NASA Astrophysics Data System (ADS)

    Gonzaga, S.; et al.

    2011-03-01

    ACS was designed to provide a deep, wide-field survey capability from the visible to near-IR using the Wide Field Camera (WFC), high resolution imaging from the near-UV to near-IR with the now-defunct High Resolution Camera (HRC), and solar-blind far-UV imaging using the Solar Blind Camera (SBC). The discovery efficiency of ACS's Wide Field Channel (i.e., the product of WFC's field of view and throughput) is 10 times greater than that of WFPC2. The failure of ACS's CCD electronics in January 2007 brought a temporary halt to CCD imaging until Servicing Mission 4 in May 2009, when WFC functionality was restored. Unfortunately, the high-resolution optical imaging capability of HRC was not recovered.

  5. Defining the Product Chemical Space of Monoterpenoid Synthases

    PubMed Central

    Tian, Boxue; Poulter, C. Dale; Jacobson, Matthew P.

    2016-01-01

    Terpenoid synthases create diverse carbon skeletons by catalyzing complex carbocation rearrangements, making them particularly challenging for enzyme function prediction. To begin to address this challenge, we have developed a computational approach for the systematic enumeration of terpenoid carbocations. Application of this approach allows us to systematically define a nearly complete chemical space for the potential carbon skeletons of products from monoterpenoid synthases. Specifically, 18758 carbocations were generated, which we cluster into 74 cyclic skeletons. Five of the 74 skeletons are found in known natural products; some of the others are plausible for new functions, either in nature or engineered. This work systematizes the description of function for this class of enzymes, and provides a basis for predicting functions of uncharacterized enzymes. To our knowledge, this is the first computational study to explore the complete product chemical space of this important class of enzymes. PMID:27517297

  6. Defining the Product Chemical Space of Monoterpenoid Synthases.

    PubMed

    Tian, Boxue; Poulter, C Dale; Jacobson, Matthew P

    2016-08-01

    Terpenoid synthases create diverse carbon skeletons by catalyzing complex carbocation rearrangements, making them particularly challenging for enzyme function prediction. To begin to address this challenge, we have developed a computational approach for the systematic enumeration of terpenoid carbocations. Application of this approach allows us to systematically define a nearly complete chemical space for the potential carbon skeletons of products from monoterpenoid synthases. Specifically, 18758 carbocations were generated, which we cluster into 74 cyclic skeletons. Five of the 74 skeletons are found in known natural products; some of the others are plausible for new functions, either in nature or engineered. This work systematizes the description of function for this class of enzymes, and provides a basis for predicting functions of uncharacterized enzymes. To our knowledge, this is the first computational study to explore the complete product chemical space of this important class of enzymes. PMID:27517297

  7. S-sulfocysteine synthase function in sensing chloroplast redox status

    PubMed Central

    Gotor, Cecilia; Romero, Luis C.

    2013-01-01

    The minor chloroplastic O-acetylserine(thiol)lyase isoform encoded by the CS26 gene in Arabidopsis thaliana has been described as an S-sulfocysteine synthase enzyme that plays an important role in chloroplast function. This enzyme is located in the thylakoid lumen, and its S-sulfocysteine activity is essential for the proper photosynthetic performance of the chloroplast under long-day growth conditions. Based on the present knowledge of this enzyme, we suggest that S-sulfocysteine synthase functions as a protein sensor to detect the accumulation of thiosulfate as a result of the inadequate detoxification of reactive oxygen species generated under conditions of excess light to produce the S-sulfocysteine molecule that triggers protection mechanisms of the photosynthetic apparatus. PMID:23333972

  8. Visualization of cellulose synthases in Arabidopsis secondary cell walls.

    PubMed

    Watanabe, Y; Meents, M J; McDonnell, L M; Barkwill, S; Sampathkumar, A; Cartwright, H N; Demura, T; Ehrhardt, D W; Samuels, A L; Mansfield, S D

    2015-10-01

    Cellulose biosynthesis in plant secondary cell walls forms the basis of vascular development in land plants, with xylem tissues constituting the vast majority of terrestrial biomass. We used plant lines that contained an inducible master transcription factor controlling xylem cell fate to quantitatively image fluorescently tagged cellulose synthase enzymes during cellulose deposition in living protoxylem cells. The formation of secondary cell wall thickenings was associated with a redistribution and enrichment of CESA7-containing cellulose synthase complexes (CSCs) into narrow membrane domains. The velocities of secondary cell wall-specific CSCs were faster than those of primary cell wall CSCs during abundant cellulose production. Dynamic intracellular of endomembranes, in combination with increased velocity and high density of CSCs, enables cellulose to be synthesized rapidly in secondary cell walls. PMID:26450210

  9. Use of linalool synthase in genetic engineering of scent production

    DOEpatents

    Pichersky, Eran

    1998-01-01

    A purified S-linalool synthase polypeptide from Clarkia breweri is disclosed as is the recombinant polypeptide and nucleic acid sequences encoding the polypeptide. Also disclosed are antibodies immunoreactive with the purified peptide and with recombinant versions of the polypeptide. Methods of using the nucleic acid sequences, as well as methods of enhancing the smell and the flavor of plants expressing the nucleic acid sequences are also disclosed.

  10. Inhibition of Escherichia coli ATP synthase by amphibian antimicrobial peptides.

    PubMed

    Laughlin, Thomas F; Ahmad, Zulfiqar

    2010-04-01

    Previously melittin, the alpha-helical basic honey bee venom peptide, was shown to inhibit F(1)-ATPase by binding at the beta-subunit DELSEED motif of F(1)F(o)-ATP synthase. Herein, we present the inhibitory effects of the basic alpha-helical amphibian antimicrobial peptides, ascaphin-8, aurein 2.2, aurein 2.3, carein 1.8, carein 1.9, citropin 1.1, dermaseptin, maculatin 1.1, maganin II, MRP, or XT-7, on purified F(1) and membrane bound F(1)F(0)Escherichia coli ATP synthase. We found that the extent of inhibition by amphibian peptides is variable. Whereas MRP-amide inhibited ATPase essentially completely (approximately 96% inhibition), carein 1.8 did not inhibit at all (0% inhibition). Inhibition by other peptides was partial with a range of approximately 13-70%. MRP-amide was also the most potent inhibitor on molar scale (IC(50) approximately 3.25 microM). Presence of an amide group at the c-terminal of peptides was found to be critical in exerting potent inhibition of ATP synthase ( approximately 20-40% additional inhibition). Inhibition was fully reversible and found to be identical in both F(1)F(0) membrane preparations as well as in isolated purified F(1). Interestingly, growth of E. coli was abrogated in the presence of ascaphin-8, aurein 2.2, aurein 2.3, citropin 1.1, dermaseptin, magainin II-amide, MRP, MRP-amide, melittin, or melittin-amide but was unaffected in the presence of carein 1.8, carein 1.9, maculatin 1.1, magainin II, or XT-7. Hence inhibition of F(1)-ATPase and E. coli cell growth by amphibian antimicrobial peptides suggests that their antimicrobial/anticancer properties are in part linked to their actions on ATP synthase. PMID:20100509

  11. Structure and Mechanistic Implications of a Tryptophan Synthase Quinonoid Intermediate

    SciTech Connect

    Barends,T.; Domratcheva, T.; Kulik, V.; Blumenstein, L.; Niks, D.; Dunn, M.; Schlichting, I.

    2008-01-01

    Quinonoid intermediates play a key role in the catalytic mechanism of pyridoxal 5'-phosphate (PLP)-dependent enzymes. Whereas structures of other PLP-bound reaction intermediates have been determined, a high-quality structure of a quinonoid species has not been reported. We present the crystal structure of the indoline quinonoid intermediate of tryptophan synthase (see figure) and discuss its implications for the enzymatic mechanism and allosteric regulation.

  12. Purification of geranylgeranyl diphosphate synthase from bovine brain.

    PubMed

    Sagami, H; Morita, Y; Korenaga, T; Ogura, K

    1994-01-01

    Geranylgeranyl diphosphate (GGPP) synthase was purified to homogeneity from bovine brain in a one-step affinity column procedure. For the construction of the affinity column, a farnesyl diphosphate (FPP) analog, O-(6-amino-1-hexyl)-P-farnesylmethyl phosphonophosphate, was synthesized and linked to the spacer of the matrix of Affigel 10 via the amino group. The native enzyme appeared to be homooligomer (150-195 kDa) with a molecular mass of the monomer of 37.5 kDa. The pI for the enzyme was 6.2. The Km values for dimethylallyl diphosphate (DMAPP), geranyl diphosphate (GPP) and FPP were estimated to be 33 microM, 0.80 microM and 0.74 microM, respectively. The Km value for isopentenyl diphosphate (IPP) in the presence of both IPP and FPP mixture was 2 microM. The ratio of the reaction velocity for formation of GGPP from DMAPP, GPP or FPP was 0.004:0.145:1. The intermediate FPP was formed in the reaction with GPP as an allylic primer. FPP synthase catalyzing the formation of FPP from DMAPP and IPP was also purified to homogeneity from the same organ by a similar affinity chromatography procedure using a GPP analog, O-(6-amino-1-hexyl)-P-geranylmethyl phosphonophosphate as a ligand. The enzyme was a homodimer with a monomeric molecular mass of 40.0 kDa. These results indicate that GGPP, a lipid precursor for the biosynthesis of a majority of prenylated proteins, is synthesized from DMAPP and IPP by the action of FPP synthase catalyzing the reactions C5-->C15 followed by the action of GGPP synthase catalyzing the reaction C15-->C20. PMID:7856400

  13. Use of linalool synthase in genetic engineering of scent production

    DOEpatents

    Pichersky, E.

    1998-12-15

    A purified S-linalool synthase polypeptide from Clarkia breweri is disclosed as is the recombinant polypeptide and nucleic acid sequences encoding the polypeptide. Also disclosed are antibodies immunoreactive with the purified peptide and with recombinant versions of the polypeptide. Methods of using the nucleic acid sequences, as well as methods of enhancing the smell and the flavor of plants expressing the nucleic acid sequences are also disclosed. 5 figs.

  14. Expression of prostaglandin E synthases in the bovine oviduct.

    PubMed

    Gauvreau, D; Moisan, V; Roy, M; Fortier, M A; Bilodeau, J-F

    2010-01-01

    The oviduct is a specialized organ responsible for the storage and the transport of male and female gametes. It also provides an optimal environment for final gamete maturation, fertilization, and early embryo development. Prostaglandin (PG) E(2) is involved in many female reproductive functions, including ovulation, fertilization, implantation, and parturition. However, the control of its synthesis in the oviduct is not fully understood. Cyclooxygenases (COXs) are involved in the first step of the transformation of arachidonic acid to PGH(2.) The prostaglandin E synthases (PGESs) constitute a family of enzymes that catalyze the conversion of PGH(2) to PGE(2), the terminal step in the formation of this bioactive prostaglandin. Quantitative real-time PCR was used to determine the expression of COX-1, COX-2, microsomal prostaglandin E synthase-1 (mPGES-1), microsomal prostaglandin E synthase-2 (mPGES-2), and cytosolic prostaglandin E synthase (cPGES) mRNA in various sections of the oviduct, both ipsilateral and contralateral (to the ovary on which ovulation occurred) at various stages of the estrous cycle. Furthermore, protein expression and localization of cPGES, mPGES-1, and mPGES-2 were determined by Western blot and immunohistochemistry. All three PGESs were detected at both mRNA and protein levels in the oviduct. These PGESs were mostly concentrated in the oviductal epithelial layer and primarily expressed in the ampulla section of the oviduct and to a lesser extent in the isthmus and the isthmic-ampullary junction. The mPGES-1 protein was highly expressed in the contralateral oviduct, which contrasted with mPGES-2 mostly expressed in the ipsilateral oviduct. This is apparently the first report documenting that the three PGESs involved in PGE(2) production were present in the Bos taurus oviduct. PMID:19875162

  15. Piriformospora indica requires kaurene synthase activity for successful plant colonization.

    PubMed

    Li, Liang; Chen, Xi; Ma, Chaoyang; Wu, Hongqing; Qi, Shuting

    2016-05-01

    Ent-kaurene (KS) synthases and ent-kaurene-like (KSL) synthases are involved in the biosynthesis of phytoalexins and/or gibberellins which play a role in plant immunity and development. The relationship between expression of five synthase genes (HvKSL1, HvKS2, HvKS4, HvKS5, HvKSL4) and plant colonization by the endophytic fungus Piriformospora indica was assessed in barley (Hordeum vulgare). The KS gene family is differently up-regulated at 1, 3 and 7 day after P. indica inoculation. By comparison, the HvKSL4 gene expression pattern is more significantly affected by UV irradiation and P. indica colonization. The characterizations of two silencing lines (HvKSL1-RNAi, HvKSL4-RNAi) also were analyzed. HvKSL1-RNAi and HvKSL4-RNAi lines in the first generation lead to less dark green leaves and slower plant development. Further, reduced spikelet fertility in progenies of RNAi plants heterozygous for HvKSL1 were observed, but not for HvKSL4. T2 generation of HvKSL1-RNAi line showed semi-dwarf phenotype while the wild type phenotype could be restored by applying GA3. Silencing of HvKSL4 and HvKSL1 resulted in reduced colonization by P. indica especially in the HvKSL1-RNAi line. These results probably suggest the presence of two ent-KS synthase in barley, one (HvKSL1) that participates in the biosynthesis of GAs and another (HvKSL4) that is involved in the biosynthesis of phytoalexins. PMID:26943021

  16. Inhibition of Escherichia coli ATP synthase by amphibian antimicrobial peptides

    PubMed Central

    Laughlin, Thomas F.; Ahmad, Zulfiqar

    2010-01-01

    Previously melittin, the α-helical basic honey bee venom peptide, was shown to inhibit F1-ATPase by binding at the β-subunit DELSEED motif of F1Fo ATP synthase. Herein, we present the inhibitory effects of the basic α-helical amphibian antimicrobial peptides, ascaphin-8, aurein 2.2, aurein 2.3, carein 1.8, carein 1.9, citropin 1.1, dermaseptin, maculatin 1.1, maganin II, MRP, or XT-7, on purified F1 and membrane bound F1Fo E. coli ATP synthase. We found that the extent of inhibition by amphibian peptides is variable. Whereas MRP-amide inhibited ATPase essentially completely (~96% inhibition), carein 1.8 did not inhibit at all (0% inhibition). Inhibition by other peptides was partial with a range of ~13% to 70%. MRP-amide was also the most potent inhibitor on molar scale (IC50 ~3.25 µM). Presence of an amide group at the c-terminal of peptides was found to be critical in exerting potent inhibition of ATP synthase (~20–40% additional inhibition). Inhibition was fully reversible and found to be identical in both F1Fo membrane preparations as well as in isolated purified F1. Interestingly, growth of Escherichia coli was abrogated in the presence of ascaphin-8, aurein 2.2, aurein 2.3, citropin 1.1, dermaseptin, magainin II-amide, MRP, MRP-amide, melittin, or melittin-amide but was unaffected in the presence of carein 1.8, carein 1.9, maculatin 1.1, magainin II, or XT-7. Hence inhibition of F1-ATPase and E. coli cell growth by amphibian antimicrobial peptides suggests that their antimicrobial/anticancer properties are in part linked to their actions on ATP synthase. PMID:20100509

  17. AC loss in superconducting tapes and cables

    NASA Astrophysics Data System (ADS)

    Oomen, Marijn Pieter

    High-temperature superconductors are developed for use in power-transmission cables, transformers and motors. The alternating magnetic field in these devices causes AC loss, which is a critical factor in the design. The study focuses on multi-filament Bi-2223/Ag tapes exposed to a 50-Hz magnetic field at 77 K. The AC loss is measured with magnetic, electric and calorimetric methods. The results are compared to theoretical predictions based mainly on the Critical-State Model. The loss in high- temperature superconductors is affected by their characteristic properties: increased flux creep, high aspect ratio and inhomogeneties. Filament intergrowths and a low matrix resistivity cause a high coupling-current loss especially when the filaments are fully coupled. When the wide side of the tape is parallel to the external magnetic field, the filaments are decoupled by twisting. In a perpendicular field the filaments can be decoupled only by combining a short twist pitch with a transverse resistivity much higher than that of silver. The arrangement of the inner filaments determines the transverse resistivity. Ceramic barriers around the filaments cause partial decoupling in perpendicular magnetic fields at power frequencies. The resultant decrease in AC loss is greater than the accompanying decrease in critical current. With direct transport current in alternating magnetic field, the transport-current loss is well described with a new model for the dynamic resistance. The Critical- State Model describes well the magnetisation and total AC loss in parallel magnetic fields, at transport currents up to 0.7 times the critical current. When tapes are stacked face-to-face in a winding, the AC-loss density in perpendicular fields is greatly decreased due to the mutual shielding of the tapes. Coupling currents between the tapes in a cable cause an extra AC loss, which is reduced by a careful cable design. The total AC loss in complex devices with many tapes is generally well

  18. Suites of Terpene Synthases Explain Differential Terpenoid Production in Ginger and Turmeric Tissues

    PubMed Central

    Koo, Hyun Jo; Gang, David R.

    2012-01-01

    The essential oils of ginger (Zingiber officinale) and turmeric (Curcuma longa) contain a large variety of terpenoids, some of which possess anticancer, antiulcer, and antioxidant properties. Despite their importance, only four terpene synthases have been identified from the Zingiberaceae family: (+)-germacrene D synthase and (S)-β-bisabolene synthase from ginger rhizome, and α-humulene synthase and β-eudesmol synthase from shampoo ginger (Zingiber zerumbet) rhizome. We report the identification of 25 mono- and 18 sesquiterpene synthases from ginger and turmeric, with 13 and 11, respectively, being functionally characterized. Novel terpene synthases, (−)-caryolan-1-ol synthase and α-zingiberene/β-sesquiphellandrene synthase, which is responsible for formation of the major sesquiterpenoids in ginger and turmeric rhizomes, were also discovered. These suites of enzymes are responsible for formation of the majority of the terpenoids present in these two plants. Structures of several were modeled, and a comparison of sets of paralogs suggests how the terpene synthases in ginger and turmeric evolved. The most abundant and most important sesquiterpenoids in turmeric rhizomes, (+)-α-turmerone and (+)-β-turmerone, are produced from (−)-α-zingiberene and (−)-β-sesquiphellandrene, respectively, via α-zingiberene/β-sesquiphellandrene oxidase and a still unidentified dehydrogenase. PMID:23272109

  19. [BIOINFORMATIC SEARCH AND PHYLOGENETIC ANALYSIS OF THE CELLULOSE SYNTHASE GENES OF FLAX (LINUM USITATISSIMUM)].

    PubMed

    Pydiura, N A; Bayer, G Ya; Galinousky, D V; Yemets, A I; Pirko, Ya V; Podvitski, T A; Anisimova, N V; Khotyleva, L V; Kilchevsky, A V; Blume, Ya B

    2015-01-01

    A bioinformatic search of sequences encoding cellulose synthase genes in the flax genome, and their comparison to dicots orthologs was carried out. The analysis revealed 32 cellulose synthase gene candidates, 16 of which are highly likely to encode cellulose synthases, and the remaining 16--cellulose synthase-like proteins (Csl). Phylogenetic analysis of gene products of cellulose synthase genes allowed distinguishing 6 groups of cellulose synthase genes of different classes: CesA1/10, CesA3, CesA4, CesA5/6/2/9, CesA7 and CesA8. Paralogous sequences within classes CesA1/10 and CesA5/6/2/9 which are associated with the primary cell wall formation are characterized by a greater similarity within these classes than orthologous sequences. Whereas the genes controlling the biosynthesis of secondary cell wall cellulose form distinct clades: CesA4, CesA7, and CesA8. The analysis of 16 identified flax cellulose synthase gene candidates shows the presence of at least 12 different cellulose synthase gene variants in flax genome which are represented in all six clades of cellulose synthase genes. Thus, at this point genes of all ten known cellulose synthase classes are identify in flax genome, but their correct classification requires additional research. PMID:26638491

  20. Potential Functional Replacement of the Plastidic Acetyl-CoA Carboxylase Subunit (accD) Gene by Recent Transfers to the Nucleus in Some Angiosperm Lineages1[W][OA

    PubMed Central

    Rousseau-Gueutin, Mathieu; Huang, Xun; Higginson, Emily; Ayliffe, Michael; Day, Anil; Timmis, Jeremy N.

    2013-01-01

    Eukaryotic cells originated when an ancestor of the nucleated cell engulfed bacterial endosymbionts that gradually evolved into the mitochondrion and the chloroplast. Soon after these endosymbiotic events, thousands of ancestral prokaryotic genes were functionally transferred from the endosymbionts to the nucleus. This process of functional gene relocation, now rare in eukaryotes, continues in angiosperms. In this article, we show that the chloroplastic acetyl-CoA carboxylase subunit (accD) gene that is present in the plastome of most angiosperms has been functionally relocated to the nucleus in the Campanulaceae. Surprisingly, the nucleus-encoded accD transcript is considerably smaller than the plastidic version, consisting of little more than the carboxylase domain of the plastidic accD gene fused to a coding region encoding a plastid targeting peptide. We verified experimentally the presence of a chloroplastic transit peptide by showing that the product of the nuclear accD fused to green fluorescent protein was imported in the chloroplasts. The nuclear gene regulatory elements that enabled the erstwhile plastidic gene to become functional in the nuclear genome were identified, and the evolution of the intronic and exonic sequences in the nucleus is described. Relocation and truncation of the accD gene is a remarkable example of the processes underpinning endosymbiotic evolution. PMID:23435694

  1. Multi-Substrate Terpene Synthases: Their Occurrence and Physiological Significance.

    PubMed

    Pazouki, Leila; Niinemets, Ülo

    2016-01-01

    Terpene synthases are responsible for synthesis of a large number of terpenes in plants using substrates provided by two distinct metabolic pathways, the mevalonate-dependent pathway that is located in cytosol and has been suggested to be responsible for synthesis of sesquiterpenes (C15), and 2-C-methyl-D-erythritol-4-phosphate pathway located in plastids and suggested to be responsible for the synthesis of hemi- (C5), mono- (C10), and diterpenes (C20). Recent advances in characterization of genes and enzymes responsible for substrate and end product biosynthesis as well as efforts in metabolic engineering have demonstrated existence of a number of multi-substrate terpene synthases. This review summarizes the progress in the characterization of such multi-substrate terpene synthases and suggests that the presence of multi-substrate use might have been significantly underestimated. Multi-substrate use could lead to important changes in terpene product profiles upon substrate profile changes under perturbation of metabolism in stressed plants as well as under certain developmental stages. We therefore argue that multi-substrate use can be significant under physiological conditions and can result in complicate modifications in terpene profiles. PMID:27462341

  2. Kinetic Characterization of Spinach Leaf Sucrose-Phosphate Synthase 1

    PubMed Central

    Amir, Jacob; Preiss, Jack

    1982-01-01

    The spinach (Spinacia oleracea) leaf sucrose-phosphate synthase was partially purified via DEAE-cellulose chromatography, and its kinetic properties were studied. Fructose-6-phosphate saturation curves were sigmoidal, while UDPglucose saturation curves were hyperbolic. At subsaturating concentrations of fructose-6-phosphate, 1,5 anhydroglucitol-6-phosphate had a stimulatory effect on enzyme activity, suggesting multiple and interacting fructose-6-phosphate sites on sucrose-phosphate synthase. The concentrations required for 50% of maximal activity were 3.0 millimolar and 1.3 millimolar, respectively, for fructose-6-phosphate and UDPglucose. The enzyme was not stimulated by divalent cations. Inorganic phosphate proved to be a potent inhibitor, particularly at low concentrations of substrate. Phosphate inhibition was competitive with UDPglucose, and its Ki was determined to be 1.75 millimolar. Sucrose phosphate, the product of the reaction, was also shown to be a competitive inhibitor towards UDPglucose concentration and had Ki of 0.4 millimolar. The kinetic results suggest that spinach leaf sucrose-phospahte synthase is a regulatory enzyme and that its activity is modulated by the concentrations of phosphate, fructose-6-phosphate, and UDPglucose occurring in the cytoplasm of the leaf cell. PMID:16662338

  3. Dexmedetomidine inhibits vasoconstriction via activation of endothelial nitric oxide synthase.

    PubMed

    Nong, Lidan; Ma, Jue; Zhang, Guangyan; Deng, Chunyu; Mao, Songsong; Li, Haifeng; Cui, Jianxiu

    2016-09-01

    Despite the complex vascular effects of dexmedetomidine (DEX), its actions on human pulmonary resistance arteries remain unknown. The present study tested the hypothesis that DEX inhibits vascular tension in human pulmonary arteries through the endothelial nitric oxide synthase (eNOS) mediated production of nitric oxide (NO). Pulmonary artery segments were obtained from 62 patients who underwent lung resection. The direct effects of DEX on human pulmonary artery tension and changes in vascular tension were determined by isometric force measurements recorded on a myograph. Arterial contractions caused by increasing concentrations of serotonin with DEX in the presence or absence of L-NAME (endothelial nitric oxide synthase inhibitor), yohimbine (α2-adrenoceptor antagonist) and indomethacin (cyclooxygenase inhibitor) as antagonists were also measured. DEX had no effect on endothelium-intact pulmonary arteries, whereas at concentrations of 10(-8)~10(-6) mol/L, it elicited contractions in endothelium-denuded pulmonary arteries. DEX (0.3, 1, or 3×10(-9) mmol/L) inhibited serotonin-induced contraction in arteries with intact endothelium in a dose-dependent manner. L-NAME and yohimbine abolished DEX-induced inhibition, whereas indomethacin had no effect. No inhibitory effect was observed in endothelium-denuded pulmonary arteries. DEX-induced inhibition of vasoconstriction in human pulmonary arteries is mediated by NO production induced by the activation of endothelial α2-adrenoceptor and nitric oxide synthase. PMID:27610030

  4. [Preparation and crystallization of Polygonum cuspidatum benzalacetone synthase].

    PubMed

    Ma, Wenrui; Liu, Chunmei; Yang, Mingfeng; Xue, Feiyan; Chen, Qing; Ma, Lanqing; Lü, Heshu

    2016-02-01

    The chalcone synthase (CHS) superfamily of the type III polyketide synthases (PKSs) generates backbones of a variety of plant secondary metabolites. Benzalacetone synthase (BAS) catalyzes a condensation reaction of decarboxylation between the substrates of 4-coumaric coenzyme A and malonyl coenzyme A to generate benzylidene acetone, whose derivatives are series of compounds with various biological activities. A BAS gene Pcpks2 and a bifunctional CHS/BAS PcPKSI were isolated from medicinal plant P. cuspidatum. Crystallographic and structure-based mutagenesis studies indicate that the functional diversity of the CHS-superfamily enzymes is principally derived from small modifications of the active site architecture. In order to obtain an understanding of the biosynthesis of polyketides in P. cuspidatum, which has been poorly described, as well as of its activation mechanism, PcPKS2 was overexpressed in Escherichia coli as a C-terminally poly-His-tagged fusion protein, purified to homogeneity and crystallized, which is helpful for the clarification of the catalytic mechanism of the enzyme and lays the foundation for its genetic engineering manipulation. PMID:27382775

  5. Dexmedetomidine inhibits vasoconstriction via activation of endothelial nitric oxide synthase

    PubMed Central

    Nong, Lidan; Ma, Jue; Zhang, Guangyan; Deng, Chunyu; Mao, Songsong; Li, Haifeng

    2016-01-01

    Despite the complex vascular effects of dexmedetomidine (DEX), its actions on human pulmonary resistance arteries remain unknown. The present study tested the hypothesis that DEX inhibits vascular tension in human pulmonary arteries through the endothelial nitric oxide synthase (eNOS) mediated production of nitric oxide (NO). Pulmonary artery segments were obtained from 62 patients who underwent lung resection. The direct effects of DEX on human pulmonary artery tension and changes in vascular tension were determined by isometric force measurements recorded on a myograph. Arterial contractions caused by increasing concentrations of serotonin with DEX in the presence or absence of L-NAME (endothelial nitric oxide synthase inhibitor), yohimbine (α2-adrenoceptor antagonist) and indomethacin (cyclooxygenase inhibitor) as antagonists were also measured. DEX had no effect on endothelium-intact pulmonary arteries, whereas at concentrations of 10–8~10–6 mol/L, it elicited contractions in endothelium-denuded pulmonary arteries. DEX (0.3, 1, or 3×10–9 mmol/L) inhibited serotonin-induced contraction in arteries with intact endothelium in a dose-dependent manner. L-NAME and yohimbine abolished DEX-induced inhibition, whereas indomethacin had no effect. No inhibitory effect was observed in endothelium-denuded pulmonary arteries. DEX-induced inhibition of vasoconstriction in human pulmonary arteries is mediated by NO production induced by the activation of endothelial α2-adrenoceptor and nitric oxide synthase. PMID:27610030

  6. Resistance Phenotypes Mediated by Aminoacyl-Phosphatidylglycerol Synthases

    PubMed Central

    Arendt, Wiebke; Hebecker, Stefanie; Jäger, Sonja; Nimtz, Manfred

    2012-01-01

    The specific aminoacylation of the phospholipid phosphatidylglycerol (PG) with alanine or with lysine catalyzed by aminoacyl-phosphatidylglycerol synthases (aaPGS) was shown to render various organisms less susceptible to antibacterial agents. This study makes use of Pseudomonas aeruginosa chimeric mutant strains producing lysyl-phosphatidylglycerol (L-PG) instead of the naturally occurring alanyl-phosphatidylglycerol (A-PG) to study the resulting impact on bacterial resistance. Consequences of such artificial phospholipid composition were studied in the presence of an overall of seven antimicrobials (β-lactams, a lipopeptide antibiotic, cationic antimicrobial peptides [CAMPs]) to quantitatively assess the effect of A-PG substitution (with L-PG, L-PG and A-PG, increased A-PG levels). For the employed Gram-negative P. aeruginosa model system, an exclusive charge repulsion mechanism does not explain the attenuated antimicrobial susceptibility due to PG modification. Additionally, the specificity of nine orthologous aaPGS enzymes was experimentally determined. The newly characterized protein sequences allowed for the establishment of a significant group of A-PG synthase sequences which were bioinformatically compared to the related group of L-PG synthesizing enzymes. The analysis revealed a diverse origin for the evolution of A-PG and L-PG synthases, as the specificity of an individual enzyme is not reflected in terms of a characteristic sequence motif. This finding is relevant for future development of potential aaPGS inhibitors. PMID:22267511

  7. Mechanism of Action and Inhibition of dehydrosqualene Synthase

    SciTech Connect

    F Lin; C Liu; Y Liu; Y Zhang; K Wang; W Jeng; T Ko; R Cao; A Wang; E Oldfield

    2011-12-31

    'Head-to-head' terpene synthases catalyze the first committed steps in sterol and carotenoid biosynthesis: the condensation of two isoprenoid diphosphates to form cyclopropylcarbinyl diphosphates, followed by ring opening. Here, we report the structures of Staphylococcus aureus dehydrosqualene synthase (CrtM) complexed with its reaction intermediate, presqualene diphosphate (PSPP), the dehydrosqualene (DHS) product, as well as a series of inhibitors. The results indicate that, on initial diphosphate loss, the primary carbocation so formed bends down into the interior of the protein to react with C2,3 double bond in the prenyl acceptor to form PSPP, with the lower two-thirds of both PSPP chains occupying essentially the same positions as found in the two farnesyl chains in the substrates. The second-half reaction is then initiated by the PSPP diphosphate returning back to the Mg{sup 2+} cluster for ionization, with the resultant DHS so formed being trapped in a surface pocket. This mechanism is supported by the observation that cationic inhibitors (of interest as antiinfectives) bind with their positive charge located in the same region as the cyclopropyl carbinyl group; that S-thiolo-diphosphates only inhibit when in the allylic site; activity results on 11 mutants show that both DXXXD conserved domains are essential for PSPP ionization; and the observation that head-to-tail isoprenoid synthases as well as terpene cyclases have ionization and alkene-donor sites which spatially overlap those found in CrtM.

  8. From bacterial to human dihydrouridine synthase: automated structure determination

    SciTech Connect

    Whelan, Fiona Jenkins, Huw T.; Griffiths, Samuel C.; Byrne, Robert T.; Dodson, Eleanor J.; Antson, Alfred A.

    2015-06-30

    The crystal structure of a human dihydrouridine synthase, an enzyme associated with lung cancer, with 18% sequence identity to a T. maritima enzyme, has been determined at 1.9 Å resolution by molecular replacement after extensive molecular remodelling of the template. The reduction of uridine to dihydrouridine at specific positions in tRNA is catalysed by dihydrouridine synthase (Dus) enzymes. Increased expression of human dihydrouridine synthase 2 (hDus2) has been linked to pulmonary carcinogenesis, while its knockdown decreased cancer cell line viability, suggesting that it may serve as a valuable target for therapeutic intervention. Here, the X-ray crystal structure of a construct of hDus2 encompassing the catalytic and tRNA-recognition domains (residues 1–340) determined at 1.9 Å resolution is presented. It is shown that the structure can be determined automatically by phenix.mr-rosetta starting from a bacterial Dus enzyme with only 18% sequence identity and a significantly divergent structure. The overall fold of the human Dus2 is similar to that of bacterial enzymes, but has a larger recognition domain and a unique three-stranded antiparallel β-sheet insertion into the catalytic domain that packs next to the recognition domain, contributing to domain–domain interactions. The structure may inform the development of novel therapeutic approaches in the fight against lung cancer.

  9. Cellulose Microfibril Formation by Surface-Tethered Cellulose Synthase Enzymes.

    PubMed

    Basu, Snehasish; Omadjela, Okako; Gaddes, David; Tadigadapa, Srinivas; Zimmer, Jochen; Catchmark, Jeffrey M

    2016-02-23

    Cellulose microfibrils are pseudocrystalline arrays of cellulose chains that are synthesized by cellulose synthases. The enzymes are organized into large membrane-embedded complexes in which each enzyme likely synthesizes and secretes a β-(1→4) glucan. The relationship between the organization of the enzymes in these complexes and cellulose crystallization has not been explored. To better understand this relationship, we used atomic force microscopy to visualize cellulose microfibril formation from nickel-film-immobilized bacterial cellulose synthase enzymes (BcsA-Bs), which in standard solution only form amorphous cellulose from monomeric BcsA-B complexes. Fourier transform infrared spectroscopy and X-ray diffraction techniques show that surface-tethered BcsA-Bs synthesize highly crystalline cellulose II in the presence of UDP-Glc, the allosteric activator cyclic-di-GMP, as well as magnesium. The cellulose II cross section/diameter and the crystal size and crystallinity depend on the surface density of tethered enzymes as well as the overall concentration of substrates. Our results provide the correlation between cellulose microfibril formation and the spatial organization of cellulose synthases. PMID:26799780

  10. Rotation and structure of FoF1-ATP synthase.

    PubMed

    Okuno, Daichi; Iino, Ryota; Noji, Hiroyuki

    2011-06-01

    F(o)F(1)-ATP synthase is one of the most ubiquitous enzymes; it is found widely in the biological world, including the plasma membrane of bacteria, inner membrane of mitochondria and thylakoid membrane of chloroplasts. However, this enzyme has a unique mechanism of action: it is composed of two mechanical rotary motors, each driven by ATP hydrolysis or proton flux down the membrane potential of protons. The two molecular motors interconvert the chemical energy of ATP hydrolysis and proton electrochemical potential via the mechanical rotation of the rotary shaft. This unique energy transmission mechanism is not found in other biological systems. Although there are other similar man-made systems like hydroelectric generators, F(o)F(1)-ATP synthase operates on the nanometre scale and works with extremely high efficiency. Therefore, this enzyme has attracted significant attention in a wide variety of fields from bioenergetics and biophysics to chemistry, physics and nanoscience. This review summarizes the latest findings about the two motors of F(o)F(1)-ATP synthase as well as a brief historical background. PMID:21524994

  11. Multi-Substrate Terpene Synthases: Their Occurrence and Physiological Significance

    PubMed Central

    Pazouki, Leila; Niinemets, Ülo

    2016-01-01

    Terpene synthases are responsible for synthesis of a large number of terpenes in plants using substrates provided by two distinct metabolic pathways, the mevalonate-dependent pathway that is located in cytosol and has been suggested to be responsible for synthesis of sesquiterpenes (C15), and 2-C-methyl-D-erythritol-4-phosphate pathway located in plastids and suggested to be responsible for the synthesis of hemi- (C5), mono- (C10), and diterpenes (C20). Recent advances in characterization of genes and enzymes responsible for substrate and end product biosynthesis as well as efforts in metabolic engineering have demonstrated existence of a number of multi-substrate terpene synthases. This review summarizes the progress in the characterization of such multi-substrate terpene synthases and suggests that the presence of multi-substrate use might have been significantly underestimated. Multi-substrate use could lead to important changes in terpene product profiles upon substrate profile changes under perturbation of metabolism in stressed plants as well as under certain developmental stages. We therefore argue that multi-substrate use can be significant under physiological conditions and can result in complicate modifications in terpene profiles. PMID:27462341

  12. Characterization and expression of human bifunctional 3'-phosphoadenosine 5'-phosphosulphate synthase isoforms.

    PubMed Central

    Fuda, Hirotoshi; Shimizu, Chikara; Lee, Young C; Akita, Harukuni; Strott, Charles A

    2002-01-01

    Sulphonation, a fundamental process essential for normal growth and development, requires the sulphonate donor molecule 3'-phosphoadenosine 5'-phosphosulphate (PAPS), which is produced from ATP and inorganic sulphate by the bifunctional enzyme PAPS synthase. In humans, two genes encode isoenzymes that are 77% identical at the amino acid level, and alternative splicing creates two subtypes of PAPS synthase 2. The question as to whether distinctions in amino acid composition are reflected in differences in activity has been examined. The specific activity of the PAPS synthase 2 subtypes is 10- to 15-fold higher than that for PAPS synthase 1. The greater catalytic efficiency of the PAPS synthase 2 subtypes is demonstrated further by the 3- to 6-fold higher k(cat)/K(m) ratios for ATP and inorganic sulphate as compared with the ratios for PAPS synthase 1. In humans, PAPS synthase 1 is expressed ubiquitously, and is the dominant isoform in most tissues, whereas expression of the PAPS synthase 2 subtypes is variable and tissue-specific. It is noteworthy that, similar to other human tissues, PAPS synthase 1 also appears to be the dominant isoform expressed in cartilage. The latter finding initially created a conundrum, since there is a specific human dwarfing disorder that is known to be caused by a mutation in the PAPS synthase 2 gene. This apparent enigma would seem to be resolved by examination of cartilage from guinea-pigs as an animal model. Similar to humans, cartilage from mature animals predominantly expresses PAPS synthase 1. In contrast, expression of PAPS synthase 1 is relatively low in the cartilage of immature guinea-pigs, including the growth plate of long bones, whereas PAPS synthase 2 is the highly expressed isoenzyme. PMID:11931637

  13. Glutathione Regulates 1-Aminocyclopropane-1-Carboxylate Synthase Transcription via WRKY33 and 1-Aminocyclopropane-1-Carboxylate Oxidase by Modulating Messenger RNA Stability to Induce Ethylene Synthesis during Stress1[OPEN

    PubMed Central

    Kumar, Deepak; Hazra, Saptarshi; Chattopadhyay, Sharmila

    2015-01-01

    Glutathione (GSH) plays a fundamental role in plant defense-signaling network. Recently, we have established the involvement of GSH with ethylene (ET) to combat environmental stress. However, the mechanism of GSH-ET interplay still remains unexplored. Here, we demonstrate that GSH induces ET biosynthesis by modulating the transcriptional and posttranscriptional regulations of its key enzymes, 1-aminocyclopropane-1-carboxylate synthase (ACS) and 1-aminocyclopropane-1-carboxylate oxidase (ACO). Transgenic Arabidopsis (Arabidopsis thaliana) plants with enhanced GSH content (AtECS) exhibited remarkable up-regulation of ACS2, ACS6, and ACO1 at transcript as well as protein levels, while they were down-regulated in the GSH-depleted phytoalexin deficient2-1 (pad2-1) mutant. We further observed that GSH induced ACS2 and ACS6 transcription in a WRKY33-dependent manner, while ACO1 transcription remained unaffected. On the other hand, the messenger RNA stability for ACO1 was found to be increased by GSH, which explains our above observations. In addition, we also identified the ACO1 protein to be a subject for S-glutathionylation, which is consistent with our in silico data. However, S-glutathionylation of ACS2 and ACS6 proteins was not detected. Further, the AtECS plants exhibited resistance to necrotrophic infection and salt stress, while the pad2-1 mutant was sensitive. Exogenously applied GSH could improve stress tolerance in wild-type plants but not in the ET-signaling mutant ethylene insensitive2-1, indicating that GSH-mediated resistance to these stresses occurs via an ET-mediated pathway. Together, our investigation reveals a dual-level regulation of ET biosynthesis by GSH during stress. PMID:26463088

  14. Brazilian Angiostrongylus cantonensis haplotypes, ac8 and ac9, have two different biological and morphological profiles

    PubMed Central

    Monte, Tainá CC; Gentile, Rosana; Garcia, Juberlan; Mota, Ester; Santos, Jeannie N; Maldonado, Arnaldo

    2014-01-01

    Angiostrongylus cantonensis is the etiologic agent of eosinophilic meningoencephalitis in humans. Cases have been recorded in many parts of the world, including Brazil. The aim of this study was to compare the differences in the biology and morphology of two different Brazilian haplotypes of A. : ac8 and ac9. A significantly larger number of L1 larvae eliminated in the faeces of rodents at the beginning of the patent period was observed for ac9 haplotype and compared to the total of L1 larvae eliminated, there was a significant difference between the two haplotypes. The ac9 haplotype showed a significant difference in the proportion of female and male specimens (0.6:1), but the same was not observed for ac8 (1.2:1). The morphometric analysis showed that male and female specimens isolated from ac8 haplotype were significantly larger with respect to body length, oesophagus length, spicule length (male) and distance from the anus to the rear end (female) compared to specimens from ac9. The morphological analysis by light microscopy showed little variation in the level of bifurcations at the lateral rays in the right lobe of the copulatory bursa between the two haplotypes. The biological, morphological and morphometric variations observed between the two haplotypes agree with the observed variation at the molecular level using the cytochrome oxidase subunit I marker and reinforce the possible influence of geographical isolation on the development of these haplotypes. PMID:25591110

  15. Brassica juncea HMG-CoA synthase: localization of mRNA and protein.

    PubMed

    Nagegowda, Dinesh A; Ramalingam, Sathishkumar; Hemmerlin, Andréa; Bach, Thomas J; Chye, Mee-Len

    2005-08-01

    3-Hydroxy-3-methylglutaryl-coenzyme-A (HMG-CoA) synthase (HMGS; EC 2.3.3.10) synthesizes HMG-CoA, a substrate for mevalonate biosynthesis in the isoprenoid pathway. It catalyzes the condensation of acetyl-CoA with acetoacetyl-CoA (AcAc-CoA) to yield S-HMG-CoA and HS-CoA. In Brassica juncea (Indian mustard), HMGS is encoded by four isogenes (BjHMGS1-BjHMGS4). We have already enzymatically characterized recombinant BjHMGS1 expressed in Escherichia coli, and have identified its residues that are significant in catalysis. To further study HMGS mRNA expression that is developmentally regulated in flowers and seedlings, we have examined its mRNA distribution by in situ hybridization and reverse transcriptase-polymerase chain reaction (RT-PCR). We observed predominant localization of HMGS mRNA in the stigmas and ovules of flower buds and in the piths of seedling hypocotyls. RT-PCR analysis revealed that BjHMGS1 and BjHMGS2 but not BjHMGS3 and BjHMGS4were expressed in floral buds. To investigate the subcellular localization of BjHMGS1, we fused BjHMGS1 translationally in-frame either to the N- or C-terminus of green fluorescent protein (GFP). BjHMGS1-GFP and GFP-BjHMGS1 fusions were used in particle gun bombardment of onion epidermal cells and tobacco BY-2 cells. The GFP-BjHMGS1 construct was also used in agroinfiltration of tobacco leaves. Both GFP-fusion proteins were observed transiently expressed in the cytosol on confocal microscopy of onion epidermal cells, tobacco BY-2 cells, and agroinfiltrated tobacco leaves. Further, subcellular fractionation of total proteins from transgenic plants expressing GFP-BjHMGS1 derived from Agrobacterium-mediated transformation confirmed that BjHMGS1 is a cytosolic enzyme. We suggest that the presence of BjHMGS isoforms is likely related to the specialization of each in different cellular and metabolic processes rather than to a different intracellular compartmentation of the enzyme. PMID:15770484

  16. Chloropropionyl-CoA: a mechanism-based inhibitor of HMG-CoA synthase and fatty acid synthase

    SciTech Connect

    Miziorko, H.M.; Ahmad, F.; Behnke, C.E.

    1986-05-01

    Recent work on the mechanisms of inactivation of HMG-CoA synthase and fatty acid synthase by chloropropionyl-CoA (Cl-prop-CoA) suggests that this analog is a mechanism-based (suicide) inhibitor; the acyl group is enzymatically converted to an acrylyl derivative prior to alkylation of the target proteins. When Cl-(/sup 3/H)prop-CoA is incubated with the target enzymes, /sup 3/H/sub 2/O is produced concomitantly with enzyme inactivation; this suggests that deprotonation and chloride elimination to form an acrylyl moiety occurs. Difficulty in cleanly synthesizing acrylyl-CoA complicates direct demonstration of the intermediacy of this species. However, synthesis of a functionally equivalent reactive substrate analog, S-acrylyl-N-acetylcysteamine has been accomplished. This analog irreversibly inhibits both HMG-CoA synthase and fatty acid synthase in a site directed fashion. Concentrations required for effective inhibition (K/sub i/ values of 1.9 mM and 3.6 mM, respectively) are much higher than observed with Cl-prop-CoA. Maximal rates of inactivation (as vertical bar ..-->.. infinity) are comparable to those measured with Cl-prop-CoA, indicating that an acrylyl derivative is kinetically competent to function as an intermediate, as required if Cl-prop-CoA is a mechanism-based inhibitor. S-acrylyl-N-acetylcysteamine also inactivates HMG-CoA lyase. In this case, kinetic studies indicate that a bimolecular process is involved (k/sub 2/ = 86.7M/sup -1/min/sup -1/ at 30/sup 0/, pH 7.0).

  17. A novel N-acetylglutamate synthase architecture revealed by the crystal structure of the bifunctional enzyme from Maricaulis maris.

    PubMed

    Shi, Dashuang; Li, Yongdong; Cabrera-Luque, Juan; Jin, Zhongmin; Yu, Xiaolin; Zhao, Gengxiang; Haskins, Nantaporn; Allewell, Norma M; Tuchman, Mendel

    2011-01-01

    Novel bifunctional N-acetylglutamate synthase/kinases (NAGS/K) that catalyze the first two steps of arginine biosynthesis and are homologous to vertebrate N-acetylglutamate synthase (NAGS), an essential cofactor-producing enzyme in the urea cycle, were identified in Maricaulis maris and several other bacteria. Arginine is an allosteric inhibitor of NAGS but not NAGK activity. The crystal structure of M. maris NAGS/K (mmNAGS/K) at 2.7 Å resolution indicates that it is a tetramer, in contrast to the hexameric structure of Neisseria gonorrhoeae NAGS. The quaternary structure of crystalline NAGS/K from Xanthomonas campestris (xcNAGS/K) is similar, and cross-linking experiments indicate that both mmNAGS/K and xcNAGS are tetramers in solution. Each subunit has an amino acid kinase (AAK) domain, which is likely responsible for N-acetylglutamate kinase (NAGK) activity and has a putative arginine binding site, and an N-acetyltransferase (NAT) domain that contains the putative NAGS active site. These structures and sequence comparisons suggest that the linker residue 291 may determine whether arginine acts as an allosteric inhibitor or activator in homologous enzymes in microorganisms and vertebrates. In addition, the angle of rotation between AAK and NAT domains varies among crystal forms and subunits within the tetramer. A rotation of 26° is sufficient to close the predicted AcCoA binding site, thus reducing enzymatic activity. Since mmNAGS/K has the highest degree of sequence homology to vertebrate NAGS of NAGS and NAGK enzymes whose structures have been determined, the mmNAGS/K structure was used to develop a structural model of human NAGS that is fully consistent with the functional effects of the 14 missense mutations that were identified in NAGS-deficient patients. PMID:22174908

  18. A Novel N-Acetylglutamate Synthase Architecture Revealed by the Crystal Structure of the Bifunctional Enzyme from Maricaulis maris

    PubMed Central

    Shi, Dashuang; Li, Yongdong; Cabrera-Luque, Juan; Jin, Zhongmin; Yu, Xiaolin; Zhao, Gengxiang; Haskins, Nantaporn; Allewell, Norma M.; Tuchman, Mendel

    2011-01-01

    Novel bifunctional N-acetylglutamate synthase/kinases (NAGS/K) that catalyze the first two steps of arginine biosynthesis and are homologous to vertebrate N-acetylglutamate synthase (NAGS), an essential cofactor-producing enzyme in the urea cycle, were identified in Maricaulis maris and several other bacteria. Arginine is an allosteric inhibitor of NAGS but not NAGK activity. The crystal structure of M. maris NAGS/K (mmNAGS/K) at 2.7 Å resolution indicates that it is a tetramer, in contrast to the hexameric structure of Neisseria gonorrhoeae NAGS. The quaternary structure of crystalline NAGS/K from Xanthomonas campestris (xcNAGS/K) is similar, and cross-linking experiments indicate that both mmNAGS/K and xcNAGS are tetramers in solution. Each subunit has an amino acid kinase (AAK) domain, which is likely responsible for N-acetylglutamate kinase (NAGK) activity and has a putative arginine binding site, and an N-acetyltransferase (NAT) domain that contains the putative NAGS active site. These structures and sequence comparisons suggest that the linker residue 291 may determine whether arginine acts as an allosteric inhibitor or activator in homologous enzymes in microorganisms and vertebrates. In addition, the angle of rotation between AAK and NAT domains varies among crystal forms and subunits within the tetramer. A rotation of 26° is sufficient to close the predicted AcCoA binding site, thus reducing enzymatic activity. Since mmNAGS/K has the highest degree of sequence homology to vertebrate NAGS of NAGS and NAGK enzymes whose structures have been determined, the mmNAGS/K structure was used to develop a structural model of human NAGS that is fully consistent with the functional effects of the 14 missense mutations that were identified in NAGS-deficient patients. PMID:22174908

  19. Subunit Asa1 spans all the peripheral stalk of the mitochondrial ATP synthase of the chlorophycean alga Polytomella sp.

    PubMed

    Colina-Tenorio, Lilia; Miranda-Astudillo, Héctor; Cano-Estrada, Araceli; Vázquez-Acevedo, Miriam; Cardol, Pierre; Remacle, Claire; González-Halphen, Diego

    2016-04-01

    Mitochondrial F1FO-ATP synthase of chlorophycean algae is dimeric. It contains eight orthodox subunits (alpha, beta, gamma, delta, epsilon, OSCP, a and c) and nine atypical subunits (Asa1 to 9). These subunits build the peripheral stalk of the enzyme and stabilize its dimeric structure. The location of the 66.1kDa subunit Asa1 has been debated. On one hand, it was found in a transient subcomplex that contained membrane-bound subunits Asa1/Asa3/Asa5/Asa8/a (Atp6)/c (Atp9). On the other hand, Asa1 was proposed to form the bulky structure of the peripheral stalk that contacts the OSCP subunit in the F1 sector. Here, we overexpressed and purified the recombinant proteins Asa1 and OSCP and explored their interactions in vitro, using immunochemical techniques and affinity chromatography. Asa1 and OSCP interact strongly, and the carboxy-terminal half of OSCP seems to be instrumental for this association. In addition, the algal ATP synthase was partially dissociated at relatively high detergent concentrations, and an Asa1/Asa3/Asa5/Asa8/a/c10 subcomplex was identified. Furthermore, Far-Western analysis suggests an Asa1-Asa8 interaction. Based on these results, a model is proposed in which Asa1 spans the whole peripheral arm of the enzyme, from a region close to the matrix-exposed side of the mitochondrial inner membrane to the F1 region where OSCP is located. 3D models show elongated, helix-rich structures for chlorophycean Asa1 subunits. Asa1 subunit probably plays a scaffolding role in the peripheral stalk analogous to the one of subunit b in orthodox mitochondrial enzymes. PMID:26657474

  20. A Novel N-Acetylglutamate Synthase Architecture Revealed by the Crystal Structure of the Bifunctional Enzyme from Maricaulis maris

    SciTech Connect

    Shi, Dashuang; Li, Yongdong; Cabrera-Luque, Juan; Jin, Zhongmin; Yu, Xiaolin; Zhao, Gengxiang; Haskins, Nantaporn; Allewell, Norma M.; Tuchman, Mendel

    2012-05-24

    Novel bifunctional N-acetylglutamate synthase/kinases (NAGS/K) that catalyze the first two steps of arginine biosynthesis and are homologous to vertebrate N-acetylglutamate synthase (NAGS), an essential cofactor-producing enzyme in the urea cycle, were identified in Maricaulis maris and several other bacteria. Arginine is an allosteric inhibitor of NAGS but not NAGK activity. The crystal structure of M. maris NAGS/K (mmNAGS/K) at 2.7 {angstrom} resolution indicates that it is a tetramer, in contrast to the hexameric structure of Neisseria gonorrhoeae NAGS. The quaternary structure of crystalline NAGS/K from Xanthomonas campestris (xcNAGS/K) is similar, and cross-linking experiments indicate that both mmNAGS/K and xcNAGS are tetramers in solution. Each subunit has an amino acid kinase (AAK) domain, which is likely responsible for N-acetylglutamate kinase (NAGK) activity and has a putative arginine binding site, and an N-acetyltransferase (NAT) domain that contains the putative NAGS active site. These structures and sequence comparisons suggest that the linker residue 291 may determine whether arginine acts as an allosteric inhibitor or activator in homologous enzymes in microorganisms and vertebrates. In addition, the angle of rotation between AAK and NAT domains varies among crystal forms and subunits within the tetramer. A rotation of 26{sup o} is sufficient to close the predicted AcCoA binding site, thus reducing enzymatic activity. Since mmNAGS/K has the highest degree of sequence homology to vertebrate NAGS of NAGS and NAGK enzymes whose structures have been determined, the mmNAGS/K structure was used to develop a structural model of human NAGS that is fully consistent with the functional effects of the 14 missense mutations that were identified in NAGS-deficient patients.

  1. Identification of core 1 O-glycan T-synthase from Caenorhabditis elegans.

    PubMed

    Ju, Tongzhong; Zheng, Qinlong; Cummings, Richard D

    2006-10-01

    The common O-glycan core structure in animal glycoproteins is the core 1 disaccharide Galbeta1-3GalNAcalpha1-Ser/Thr, which is generated by the addition of Gal to GalNAcalpha1-Ser/Thr by core 1 UDP-alpha-galactose (UDP-Gal):GalNAcalpha1-Ser/Thr beta1,3-galactosyltransferase (core 1 beta3-Gal-T or T-synthase, EC2.4.1.122). Although O-glycans play important roles in vertebrates, much remains to be learned from model organisms such as the free-living nematode Caenorhabditis elegans, which offer many advantages in exploring O-glycan structure/function. Here, we report the cloning and enzymatic characterization of T-synthase from C. elegans (Ce-T-synthase). A putative C. elegans gene for T-synthase, C38H2.2, was identified in GenBank by a BlastP search using the human T-synthase protein sequence. The full-length cDNA for Ce-T-synthase, which was generated by polymerase chain reaction using a C. elegans cDNA library as the template, contains 1170 bp including the stop TAA. The cDNA encodes a protein of 389 amino acids with typical type II membrane topology and a remarkable 42.7% identity to the human T-synthase. Ce-T-synthase has seven Cys residues in the lumenal domain including six conserved Cys residues in all orthologs. The Ce-T-synthase has four potential N-glycosylation sequons, whereas the mammalian orthologs lack N-glycosylation sequons. Only one gene for Ce-T-synthase was identified in the genome-wide search, and it contains eight exons. Promoter analysis of the Ce-T-synthase using green fluorescent protein (GFP) constructs shows that the gene is expressed at all developmental stages and appears to be in all cells. Unexpectedly, only minimal activity was recovered in the recombinant, soluble Ce-T-synthase secreted from a wide variety of mammalian cell lines, whereas robust enzyme activity was recovered in the soluble Ce-T-synthase expressed in Hi-5 insect cells. Vertebrate T-synthase requires the molecular chaperone Cosmc, but our results show that Ce-T-synthase

  2. Spectroscopic Evidence for the Two C-H-Cleaving Intermediates of Aspergillus nidulans Isopenicillin N Synthase.

    PubMed

    Tamanaha, Esta; Zhang, Bo; Guo, Yisong; Chang, Wei-Chen; Barr, Eric W; Xing, Gang; St Clair, Jennifer; Ye, Shengfa; Neese, Frank; Bollinger, J Martin; Krebs, Carsten

    2016-07-20

    The enzyme isopenicillin N synthase (IPNS) installs the β-lactam and thiazolidine rings of the penicillin core into the linear tripeptide l-δ-aminoadipoyl-l-Cys-d-Val (ACV) on the pathways to a number of important antibacterial drugs. A classic set of enzymological and crystallographic studies by Baldwin and co-workers established that this overall four-electron oxidation occurs by a sequence of two oxidative cyclizations, with the β-lactam ring being installed first and the thiazolidine ring second. Each phase requires cleavage of an aliphatic C-H bond of the substrate: the pro-S-CCys,β-H bond for closure of the β-lactam ring, and the CVal,β-H bond for installation of the thiazolidine ring. IPNS uses a mononuclear non-heme-iron(II) cofactor and dioxygen as cosubstrate to cleave these C-H bonds and direct the ring closures. Despite the intense scrutiny to which the enzyme has been subjected, the identities of the oxidized iron intermediates that cleave the C-H bonds have been addressed only computationally; no experimental insight into their geometric or electronic structures has been reported. In this work, we have employed a combination of transient-state-kinetic and spectroscopic methods, together with the specifically deuterium-labeled substrates, A[d2-C]V and AC[d8-V], to identify both C-H-cleaving intermediates. The results show that they are high-spin Fe(III)-superoxo and high-spin Fe(IV)-oxo complexes, respectively, in agreement with published mechanistic proposals derived computationally from Baldwin's founding work. PMID:27193226

  3. Molecular and biochemical characterization of benzalacetone synthase and chalcone synthase genes and their proteins from raspberry (Rubus idaeus L.).

    PubMed

    Zheng, Desen; Hrazdina, Geza

    2008-02-15

    Two new members of the polyketide synthase (PKS) gene family (RiPKS4 and RiPKS5) were cloned from raspberry fruits (Rubus idaeus L., cv Royalty) and expressed in Escherichia coli. Characterization of the recombinant enzyme products indicated that RiPKS4 is a bifunctional polyketide synthase producing both 4-hydroxybenzalacetone and naringenin chalcone. The recombinant RiPKS4 protein, like the native protein from raspberry fruits [W. Borejsza-Wysocki, G. Hrazdina, Plant Physiol. 1996;110: 791-799] accepted p-coumaryl-CoA and ferulyl-CoA as starter substrates and catalyzed the formation of both naringenin chalcone, 4-hydroxy-benzalacetone and 3-methoxy-4-hydroxy-benzalacetone. Although activity of RiPKS4 was higher with ferulyl-CoA than with p-coumaryl-CoA, the corresponding product, 3-methoxy-4-hydroxy phenylbutanone could not be detected in raspberries to date. Sequence analysis of the genes and proteins suggested that this feature of RiPKS4 was created by variation in the C-terminus due to DNA recombination at the 3' region of its coding sequence. RiPKS5 is a typical chalcone synthase (CHS) that uses p-coumaryl-CoA only as starter substrate and produces naringenin chalcone exclusively as the reaction product. PMID:18068110

  4. Manipulating Flames with AC Electric Fields

    NASA Astrophysics Data System (ADS)

    Bishop, Kyle

    2013-11-01

    Time-oscillating electric fields applied to plasmas present in flames create steady flows of gas capable of shaping, directing, enhancing, or even extinguishing flames. Interestingly, electric winds induced by AC electric fields can be stronger that those due to static fields of comparable magnitude. Furthermore, unlike static fields, the electric force due to AC fields is localized near the surface of the flame. Consequently, the AC response depends only on the local field at the surface of the flame - not on the position of the electrodes used to generate the field. These results suggest that oscillating electric fields can be used to manipulate and control combustion processes at a distance. To characterize and explain these effects, we investigate a simple experimental system comprising a laminar methane-air flame positioned between two parallel-plate electrodes. We quantify both the electric and hydrodynamic response of the flame as a function of frequency and magnitude of the applied field. A theoretical model shows how steady gas flows emerge from the time-averaged electrical force due to the field-induced motion of ions generated within the flame and by their disappearance by recombination. These results provide useful insights into the application of AC fields to direct combustion processes.

  5. AC electric trapping of neutral atoms

    NASA Astrophysics Data System (ADS)

    Marian, Adela; Schlunk, Sophie; Schoellkopf, Wieland; Meijer, Gerard

    2008-05-01

    We have demonstrated trapping of ultracold ground-state ^87Rb atoms in a macroscopic ac electric trap [1]. Trapping by ac electric fields has been previously achieved for polar molecules [2], as well as Sr atoms on a chip [3], and recently for Rb atoms in a three-phase electric trap [4]. Similar to trapping of ions in a Paul trap, three-dimensional confinement in an ac electric trap is obtained by switching between two saddle-point configurations of the electric field. For the first time, this dynamic confinement is directly visualized with absorption images taken at different phases of the ac switching cycle. Stable electric trapping is observed in a narrow range of switching frequencies around 60 Hz, in agreement with trajectory calculations. In a typical experiment, about 3 x 10^5 Rb atoms are trapped with lifetimes on the order of 9 s and trap depths of about 10 μK. Additionally, we show that the atoms can be used to sensitively probe the electric fields in the trap by imaging the cloud while the fields are still on. References: 1. S. Schlunk et al., PRL 98, 223002 (2007) 2. H. L. Bethlem et al., PRA 74, 063403 (2006) 3. T. Kishimoto et al., PRL 96, 123001 (2006) 4. T. Rieger et al., PRL 99, 063001 (2007)

  6. Ac-dc converter firing error detection

    SciTech Connect

    Gould, O.L.

    1996-07-15

    Each of the twelve Booster Main Magnet Power Supply modules consist of two three-phase, full-wave rectifier bridges in series to provide a 560 VDC maximum output. The harmonic contents of the twelve-pulse ac-dc converter output are multiples of the 60 Hz ac power input, with a predominant 720 Hz signal greater than 14 dB in magnitude above the closest harmonic components at maximum output. The 720 Hz harmonic is typically greater than 20 dB below the 500 VDC output signal under normal operation. Extracting specific harmonics from the rectifier output signal of a 6, 12, or 24 pulse ac-dc converter allows the detection of SCR firing angle errors or complete misfires. A bandpass filter provides the input signal to a frequency-to-voltage converter. Comparing the output of the frequency-to-voltage converter to a reference voltage level provides an indication of the magnitude of the harmonics in the ac-dc converter output signal.

  7. AC power generation from microbial fuel cells

    NASA Astrophysics Data System (ADS)

    Lobo, Fernanda Leite; Wang, Heming; Forrestal, Casey; Ren, Zhiyong Jason

    2015-11-01

    Microbial fuel cells (MFCs) directly convert biodegradable substrates to electricity and carry good potential for energy-positive wastewater treatment. However, the low and direct current (DC) output from MFC is not usable for general electronics except small sensors, yet commercial DC-AC converters or inverters used in solar systems cannot be directly applied to MFCs. This study presents a new DC-AC converter system for MFCs that can generate alternating voltage in any desired frequency. Results show that AC power can be easily achieved in three different frequencies tested (1, 10, 60 Hz), and no energy storage layer such as capacitors was needed. The DC-AC converter efficiency was higher than 95% when powered by either individual MFCs or simple MFC stacks. Total harmonic distortion (THD) was used to investigate the quality of the energy, and it showed that the energy could be directly usable for linear electronic loads. This study shows that through electrical conversion MFCs can be potentially used in household electronics for decentralized off-grid communities.

  8. AC magnetic susceptibility of Bi2223-system

    NASA Astrophysics Data System (ADS)

    Kimishima, Y.; Inagaki, K.; Tanabe, K.; Nagata, N.; Ichiyanagi, Y.

    1998-01-01

    The AC magnetic susceptibilities χ AC of a Bi2223 sintered sample were measured by the Hartshorn bridge method. The linear AC χ' 0 showed the two-steps behavior at T C1 and T C2, where T C1 > T C2. The χ'0-data between T C1 and T C2 has no H AC-dependence and agreed well with those of powder specimen, and they can be regarded as the intragrain magnetic susceptibility. Below the inter-grain transition temperature T C2 the χ″ 0 showed a positive peak. The temperature dependence of χ' 0 and χ″ 0 were analyzed by the Bean's critical-state model. As a result, the temperature dependence of critical current density J C ∝ (1 - T/T C2) β was obtained with β = 2.3-2.6. The non-linear χ' 2 and χ″ 2 below T C2 resemble the behaviors derived from the Bean model, but the negative divergence of χ' 2 may show the evidence of d-wave paring in the present Bi2223-system.

  9. 76 FR 65633 - RIN 1904-AC43

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-24

    ... FR 56678 (September 14, 2011) to make available and invite comments on the framework document for... Part 430 RIN 1904-AC43 Energy Conservation Program: Framework Document for General Service Fluorescent... general service fluorescent lamps and incandescent reflector lamps energy conservation standards in...

  10. ACS Task Force Frames Recommendations on Education.

    ERIC Educational Resources Information Center

    Chemical and Engineering News, 1984

    1984-01-01

    Discusses findings and recommendations of an American Chemical Society (ACS) task force study on the status of chemical education in the United States. Recommendations relate to national concerns; all educational levels; elementary, secondary, university, college, and two-year college chemistry and science; chemistry careers; and industry and…

  11. Surrogate Splicing for Functional Analysis of Sesquiterpene Synthase Genes1[w

    PubMed Central

    Wu, Shuiqin; Schoenbeck, Mark A.; Greenhagen, Bryan T.; Takahashi, Shunji; Lee, Sungbeom; Coates, Robert M.; Chappell, Joseph

    2005-01-01

    A method for the recovery of full-length cDNAs from predicted terpene synthase genes containing introns is described. The approach utilizes Agrobacterium-mediated transient expression coupled with a reverse transcription-polydeoxyribonucleotide chain reaction assay to facilitate expression cloning of processed transcripts. Subsequent expression of intronless cDNAs in a suitable prokaryotic host provides for direct functional testing of the encoded gene product. The method was optimized by examining the expression of an intron-containing β-glucuronidase gene agroinfiltrated into petunia (Petunia hybrida) leaves, and its utility was demonstrated by defining the function of two previously uncharacterized terpene synthases. A tobacco (Nicotiana tabacum) terpene synthase-like gene containing six predicted introns was characterized as having 5-epi-aristolochene synthase activity, while an Arabidopsis (Arabidopsis thaliana) gene previously annotated as a terpene synthase was shown to possess a novel sesquiterpene synthase activity for α-barbatene, thujopsene, and β-chamigrene biosynthesis. PMID:15965019

  12. High voltage AC/AC electrochemical capacitor operating at low temperature in salt aqueous electrolyte

    NASA Astrophysics Data System (ADS)

    Abbas, Qamar; Béguin, François

    2016-06-01

    We demonstrate that an activated carbon (AC)-based electrochemical capacitor implementing aqueous lithium sulfate electrolyte in 7:3 vol:vol water/methanol mixture can operate down to -40 °C with good electrochemical performance. Three-electrode cell investigations show that the faradaic contributions related with hydrogen chemisorption in the negative AC electrode are thermodynamically unfavored at -40 °C, enabling the system to work as a typical electrical double-layer (EDL) capacitor. After prolonged floating of the AC/AC capacitor at 1.6 V and -40°C, the capacitance, equivalent series resistance and efficiency remain constant, demonstrating the absence of ageing related with side redox reactions at this temperature. Interestingly, when temperature is increased back to 24 °C, the redox behavior due to hydrogen storage reappears and the system behaves as a freshly prepared one.

  13. 48 CFR Appendixes A-C to Chapter 7 - [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false A Appendixes A-C to Chapter 7 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL DEVELOPMENT Appendixes A-C to Chapter 7...

  14. 48 CFR Appendixes A-C to Chapter 7 - [Reserved

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 5 2014-10-01 2014-10-01 false A Appendixes A-C to Chapter 7 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL DEVELOPMENT Appendixes A-C to Chapter 7...

  15. Ectopic ATP synthase in endothelial cells: a novel cardiovascular therapeutic target.

    PubMed

    Fu, Yi; Zhu, Yi

    2010-01-01

    Adenosine triphosphate (ATP) synthase produces ATP in cells and is found on the inner membrane of mitochondria or the cell plasma membrane (ectopic ATP synthase). Here, we summarize the functions of ectopic ATP synthase in vascular endothelial cells (ECs). Ectopic ATP synthase is involved in adenosine metabolism on the cell surface through its ATP generation or hydrolysis activity. The ATP/ADP generated by the enzyme on the plasma membrane can bind to P2X/P2Y receptors and activate the related signalling pathways to regulate endothelial function. The β-chain of ectopic ATP synthase on the EC surface can recruit inflammatory cells and activate cytotoxic activity to damage ECs and induce vascular inflammation. Angiostatin and other angiogenesis inhibitors can have anti-angiogenic functions by inhibiting ectopic ATP synthase on ECs. Moreover, ectopic ATP synthase on ECs is a receptor for apoA-I, the acceptor of cholesterol efflux, which implies that endothelial ectopic ATP synthase is involved in cholesterol metabolism. Coupling factor 6 (CF6), a part of ectopic ATP synthase, is released from ECs and can inhibit prostacyclin synthesis and promote nitric oxide (NO) degradation to enhance NO bioactivity. Because ATP/ADP generated by ectopic ATP synthase can induce NO production, substances such as CF6 can inhibit NO generation by inhibiting surface ATP/ADP production. Thus, the components of ectopic ATP synthase are associated with regulation of vascular tone. Through these functions, ectopic ATP synthase on ECs is considered a potential and novel therapeutic target for atherosclerosis, hypertension and lipid disorders. PMID:21247400

  16. Potential therapeutic target for malignant paragangliomas: ATP synthase on the surface of paraganglioma cells

    PubMed Central

    Fliedner, Stephanie MJ; Yang, Chunzhang; Thompson, Eli; Abu-Asab, Mones; Hsu, Chang-Mei; Lampert, Gary; Eiden, Lee; Tischler, Arthur S; Wesley, Robert; Zhuang, Zhengping; Lehnert, Hendrik; Pacak, Karel

    2015-01-01

    F1FoATP synthase (ATP synthase) is a ubiquitous enzyme complex in eukaryotes. In general it is localized to the mitochondrial inner membrane and serves as the last step in the mitochondrial oxidative phosphorylation of ADP to ATP, utilizing a proton gradient across the inner mitochondrial membrane built by the complexes of the electron transfer chain. However some cell types, including tumors, carry ATP synthase on the cell surface. It was suggested that cell surface ATP synthase helps tumor cells thriving on glycolysis to survive their high acid generation. Angiostatin, aurovertin, resveratrol, and antibodies against the α and β subunits of ATP synthase were shown to bind and selectively inhibit cell surface ATP synthase, promoting tumor cell death. Here we show that ATP synthase β (ATP5B) is present on the cell surface of mouse pheochromocytoma cells as well as tumor cells of human SDHB-derived paragangliomas (PGLs), while being virtually absent on chromaffin primary cells from bovine adrenal medulla by confocal microscopy. The cell surface location of ATP5B was verified in the tissue of an SDHB-derived PGL by immunoelectron microscopy. Treatment of mouse pheochromocytoma cells with resveratrol as well as ATP5B antibody led to statistically significant proliferation inhibition. Our data suggest that PGLs carry ATP synthase on their surface that promotes cell survival or proliferation. Thus, cell surface ATP synthase may present a novel therapeutic target in treating metastatic or inoperable PGLs. PMID:26101719

  17. The type I fatty acid and polyketide synthases: a tale of two megasynthases

    PubMed Central

    Tsai, Shiou-Chuan

    2008-01-01

    This review chronicles the synergistic growth of the fields of fatty acid and polyketide synthesis over the last century. In both animal fatty acid synthases and modular polyketide synthases, similar catalytic elements are covalently linked in the same order in megasynthases. Whereas in fatty acid synthases the basic elements of the design remain immutable, guaranteeing the faithful production of saturated fatty acids, in the modular polyketide synthases, the potential of the basic design has been exploited to the full for the elaboration of a wide range of secondary metabolites of extraordinary structural diversity. PMID:17898897

  18. Salmonella typhimurium mutants defective in acetohydroxy acid synthases I and II.

    PubMed

    Shaw, K J; Berg, C M; Sobol, T J

    1980-03-01

    An analysis of transposon-induced mutants shows that Salmonella typhimurium possesses two major isozymes of acetohydroxy acid synthase, the enzymes which mediate the first common step in isoleucine and valine biosynthesis. A third (minor) acetohydroxy acid synthase is present, but its significance in isoleucine and valine synthesis may be negligible. Mutants defective in acetohydroxy acid synthase II (ilvG::Tn10) require isoleucine, alpha-ketobutyrate, or threonine for growth, a mutant defective in acetohydroxy acid synthase I (ilvB::Tn5) is a prototroph, and a double mutant (ilvG::Tn10 ilvB::Tn5) requires isoleucine plus valine for growth. PMID:6245063

  19. Detection of the Messenger RNA Encoding for the Ferredoxin-Dependent Glutamate Synthase in Maize Leaf

    PubMed Central

    Commere, Bernard; Vidal, Jean; Suzuki, Akira; Gadal, Pierre; Caboche, Michel

    1986-01-01

    Ferredoxin-dependent glutamate synthase (EC 1.4.7.1), glutamate oxoglutarate aminotransferase (glutamate synthase) (GOGAT) messenger RNA was extracted from maize (Zea mays L.) leaves and partially purified through oligo(dT)-cellulose chromatography and ultracentrifugation in a sucrose gradient. mRNA were translated in vitro using a reticulocyte system. The glutamate synthase subunit was characterized by immunoprecipitation with antibodies raised against the rice (Oryza sativa L.) ferredoxin-glutamate synthase. The in vitro synthesized protein and the 145 kilodaltons genuine maize leaf subunit of GOGAT were found to comigrate in sodium dodecyl sulfate-polyacrylamide gel electrophoresis experiments. Images Fig. 1 Fig. 2 Fig. 3 PMID:16664732

  20. Expeditions INDIEN-SUD-1 &2 : Variations of the Antarctic Circumpolar Current (ACC) and of the Austral ocean in the Kerguelen sector during the Deglaciation and the last Climatic Cycles

    NASA Astrophysics Data System (ADS)

    Mazaud, Alain; Michel, Elisabeth; Crosta, Xavier; Eynaud, Frederique; Paterne, Martine; Bout-Roumazeilles, Viviane; Jaccard, Samuel

    2015-04-01

    IndienSud-1 and 2 expeditions aboard the RV Marion-Dufresne were conducted in 2011 and 2012 in the Kerguelen sector of the South Indian Ocean. Objectives are to document past ocean circulation changes, in particular the variations of the Antarctic Circumpolar Current (ACC), as well as oceanic temperature variability and frontal movement, during the last climatic cycles, with a focus on the last deglaciation. Sedimentary archives collected with the Casq and Calypso coring systems of the RV Marion-Dufresne allow producing high-resolution, well-dated sedimentary records. Comparaisons with exisiting records from other ocean-continental-glaciological archives allow examining the mechanisms involved, with a close attention paid to the temporal phasing between ocean and atmosphere proxy records, at both regional- and hemispheric scales. Past Changes in the intensity of the ACC are investigated using environmental magnetism methods, which trace amount and size of sedimentary magnetic grains. Oxygen isotopes and foraminifera faunal assemblages trace hydrological and temperature changes, while vertical mixing is documented by δ13C. A precise age scale will be derived from 14C ages determinations, augmented by regional correlations (magnetic susceptibility) to well-dated cores in the same area, thanks to a tephrochronological study of the marine cores and peat cores from the Kerguelen archipelago. Results document a stronger ACC current during glacial intervals than during interglacials over at least the last 600 kyrs. This pattern is opposite to observations of flow of the NADW branch (WBUC) south of Greenland in the North Atlantic Ocean. It suggests an inter-hemispheric antiphasing between ACC and NADW at Milankovitch timescales, with a strong circulation in the deep North Atlantic when the ACC is weak, and vice versa (thus with an ACC correlated with the GNAIW intensity). During the last deglaciation, temperature and vertical mixing increased prior to changes in the ACC