Structure-based prediction and identification of 4-epimerization activity of phosphate sugars in class II aldolases.

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Lee, Seon-Hwa; Hong, Seung-Hye; An, Jung-Ung; Kim, Kyoung-Rok; Kim, Dong-Eun; Kang, Lin-Woo; Oh, Deok-Kun

2017-05-16

Sugar 4-epimerization reactions are important for the production of rare sugars and their derivatives, which have various potential industrial applications. For example, the production of tagatose, a functional sweetener, from fructose by sugar 4-epimerization is currently constrained because a fructose 4-epimerase does not exist in nature. We found that class II D-fructose-1,6-bisphosphate aldolase (FbaA) catalyzed the 4-epimerization of D-fructose-6-phosphate (F6P) to D-tagatose-6-phosphate (T6P) based on the prediction via structural comparisons with epimerase and molecular docking and the identification of the condensed products of C3 sugars. In vivo, the 4-epimerization activity of FbaA is normally repressed. This can be explained by our results showing the catalytic efficiency of D-fructose-6-phosphate kinase for F6P phosphorylation was significantly higher than that of FbaA for F6P epimerization. Here, we identified the epimerization reactions and the responsible catalytic residues through observation of the reactions of FbaA and L-rhamnulose-1-phosphate aldolases (RhaD) variants with substituted catalytic residues using different substrates. Moreover, we obtained detailed potential epimerization reaction mechanism of FbaA and a general epimerization mechanism of the class II aldolases L-fuculose-1-phosphate aldolase, RhaD, and FbaA. Thus, class II aldolases can be used as 4-epimerases for the stereo-selective synthesis of valuable carbohydrates.

Production and application of a rare disaccharide using sucrose phosphorylase from Leuconostoc mesenteroides.

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Morimoto, Kenji; Yoshihara, Akihide; Furumoto, Toshio; Takata, Goro

2015-06-01

Sucrose phosphorylase (SPase) from Leuconostoc mesenteroides exhibited activity towards eight ketohexoses, which behaved as D-glucosyl acceptors, and α-D-glucose-1-phosphate (G1P), which behaved as a donor. All eight of these ketohexoses were subsequently transformed into the corresponding d-glucosyl-ketohexoses. Of the eight ketohexoses evaluated in the current study, d-allulose behaved as the best substrate for SPase, and the resulting d-glucosyl-d-alluloside product was found to be a non-reducing sugar with a specific optical rotation of [α]D(20) + 74.36°. D-Glucosyl-D-alluloside was identified as α-D-glucopyranosyl-(1→2)-β-D-allulofuranoside by NMR analysis. D-Glucosyl-D-alluloside exhibited an inhibitory activity towards an invertase from yeast with a Km value of 50 mM, where it behaved as a competitive inhibitor with a Ki value of 9.2 mM. D-Glucosyl-D-alluloside was also successfully produced from sucrose using SPase and D-tagatose 3-epimerase. This process also allowed for the production of G1P from sucrose and d-allulose from D-fructose, which suggested that this method could be used to prepare d-glucosyl-d-alluloside without the need for expensive reagents such as G1P and d-allulose. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Co-expression of D-glucose isomerase and D-psicose 3-epimerase: development of an efficient one-step production of D-psicose.

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Men, Yan; Zhu, Yueming; Zeng, Yan; Izumori, Ken; Sun, Yuanxia; Ma, Yanhe

2014-10-01

D-Psicose has been attracting attention in recent years because of its alimentary activities and is used as an ingredient in a range of foods and dietary supplements. To develop a one-step enzymatic process of D-psicose production, thermoactive D-glucose isomerase and the D-psicose 3-epimerase obtained from Bacillus sp. and Ruminococcus sp., respectively, were successfully co-expressed in Escherichia coli BL21 strain. The substrate of one-step enzymatic process was D-glucose. The co-expression system exhibited maximum activity at 65 °C and pH 7.0. Mg(2+) could enhance the output of D-psicose by 2.32 fold to 1.6 g/L from 10 g/L of D-glucose. When using high-fructose corn syrup (HFCS) as substrate, 135 g/L D-psicose was produced under optimum conditions. The mass ratio of D-glucose, D-fructose, and D-psicose was almost 3.0:2.7:1.0, when the reaction reached equilibrium after an 8h incubation time. This co-expression system approaching to produce D-psicose has potential application in food and beverage products, especially softdrinks. Copyright © 2014 Elsevier Inc. All rights reserved.

Biochemical characterization of a D-psicose 3-epimerase from Treponema primitia ZAS-1 and its application on enzymatic production of D-psicose.

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Zhang, Wenli; Zhang, Tao; Jiang, Bo; Mu, Wanmeng

2016-01-15

The rare sugar D-psicose is a hexoketose monosaccharide and a C-3 epimer of D-fructose. D-Psicose is a novel functional sweetener with 70% of the sweetness but only 0.3% of the energy content of sucrose. Generally, the industrial production of D-psicose involves a bioconversion from D-fructose induced by ketose 3-epimerases. The D-psicose 3-epimerase (DPEase) gene from Treponema primitia ZAS-1 (Trpr-DPEase) was cloned and overexpressed in Escherichia coli BL21 (DE3). The recombinant enzyme was purified with a molecular mass of 33 kDa. Trpr-DPEase exhibited optimal activity at pH 8.0 and 70 °C and was sensitive to temperature, with relative thermal stability below 50 °C. It was strictly metal-dependent and displayed maximum catalytic activity with 450 µmol L(-1) Co(2+). The Km values of the enzyme for D-psicose and D-fructose were 209 and 279 mmol L(-1) respectively. The D-psicose/D-fructose equilibrium ratio of Trpr-DPEase was 28:72. A novel DPEase from T. primitia ZAS-1 was characterized that could catalyze the formation of D-psicose from D-fructose. D-Psicose was produced at a yield of 137.5 g L(-1) from 500 g L(-1) D-fructose, suggesting that Trpr-DPEase might be appropriate for the industrial production of D-psicose. © 2015 Society of Chemical Industry.

Purification, crystallization and preliminary crystallographic study of an IDS-epimerase from Agrobacterium tumefaciens BY6

International Nuclear Information System (INIS)

Bäuerle, Bettina; Sandalova, Tatyana; Schneider, Gunter; Rieger, Paul-Gerhard

2006-01-01

This is the first report of the crystallization of an IDS-epimerase from A. tumefaciens BY6 and its l-selenomethionine derivative. The initial degradation of all stereoisomers of the complexing agent iminodisuccinate (IDS) is enabled by an epimerase in the bacterial strain Agrobacterium tumefaciens BY6. This protein was produced in Escherichia coli, purified and crystallized by the hanging-drop vapour-diffusion method. Crystals of IDS-epimerase were obtained under several conditions. The best diffracting crystals were grown in 22% PEG 3350, 0.2 M (NH 4 ) 2 SO 4 and 0.1 M bis-Tris propane pH 7.2 at 293 K. These crystals belong to the monoclinic space group P2 1 , with unit-cell parameters a = 55.4, b = 104.2, c = 78.6 Å, β = 103.3°, and diffracted to 1.7 Å resolution. They contain two protein molecules per asymmetric unit. In order to solve the structure using the MAD phasing method, crystals of the l-selenomethionine-substituted epimerase were grown in the presence of 20% PEG 3350, 0.2 M Na 2 SO 4 and 0.1 M bis-Tris propane pH 8.5

Directed divergent evolution of a thermostable D-tagatose epimerase towards improved activity for two hexose substrates.

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Bosshart, Andreas; Hee, Chee Seng; Bechtold, Matthias; Schirmer, Tilman; Panke, Sven

2015-03-02

Functional promiscuity of enzymes can often be harnessed as the starting point for the directed evolution of novel biocatalysts. Here we describe the divergent morphing of an engineered thermostable variant (Var8) of a promiscuous D-tagatose epimerase (DTE) into two efficient catalysts for the C3 epimerization of D-fructose to D-psicose and of L-sorbose to L-tagatose. Iterative single-site randomization and screening of 48 residues in the first and second shells around the substrate-binding site of Var8 yielded the eight-site mutant IDF8 (ninefold improved kcat for the epimerization of D-fructose) and the six-site mutant ILS6 (14-fold improved epimerization of L-sorbose), compared to Var8. Structure analysis of IDF8 revealed a charged patch at the entrance of its active site; this presumably facilitates entry of the polar substrate. The improvement in catalytic activity of variant ILS6 is thought to relate to subtle changes in the hydration of the bound substrate. The structures can now be used to select additional sites for further directed evolution of the ketohexose epimerase. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Crystal structures of D-tagatose 3-epimerase from Pseudomonas cichorii and its complexes with D-tagatose and D-fructose.

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Yoshida, Hiromi; Yamada, Mitsugu; Nishitani, Takeyori; Takada, Goro; Izumori, Ken; Kamitori, Shigehiro

2007-11-23

Pseudomonas cichoriiid-tagatose 3-epimerase (P. cichoriid-TE) can efficiently catalyze the epimerization of not only d-tagatose to d-sorbose, but also d-fructose to d-psicose, and is used for the production of d-psicose from d-fructose. The crystal structures of P. cichoriid-TE alone and in complexes with d-tagatose and d-fructose were determined at resolutions of 1.79, 2.28, and 2.06 A, respectively. A subunit of P. cichoriid-TE adopts a (beta/alpha)(8) barrel structure, and a metal ion (Mn(2+)) found in the active site is coordinated by Glu152, Asp185, His211, and Glu246 at the end of the beta-barrel. P. cichoriid-TE forms a stable dimer to give a favorable accessible surface for substrate binding on the front side of the dimer. The simulated omit map indicates that O2 and O3 of d-tagatose and/or d-fructose coordinate Mn(2+), and that C3-O3 is located between carboxyl groups of Glu152 and Glu246, supporting the previously proposed mechanism of deprotonation/protonation at C3 by two Glu residues. Although the electron density is poor at the 4-, 5-, and 6-positions of the substrates, substrate-enzyme interactions can be deduced from the significant electron density at O6. The O6 possibly interacts with Cys66 via hydrogen bonding, whereas O4 and O5 in d-tagatose and O4 in d-fructose do not undergo hydrogen bonding to the enzyme and are in a hydrophobic environment created by Phe7, Trp15, Trp113, and Phe248. Due to the lack of specific interactions between the enzyme and its substrates at the 4- and 5-positions, P. cichoriid-TE loosely recognizes substrates in this region, allowing it to efficiently catalyze the epimerization of d-tagatose and d-fructose (C4 epimer of d-tagatose) as well. Furthermore, a C3-O3 proton-exchange mechanism for P. cichoriid-TE is suggested by X-ray structural analysis, providing a clear explanation for the regulation of the ionization state of Glu152 and Glu246.

Purification, crystallization and preliminary crystallographic study of an IDS-epimerase from Agrobacterium tumefaciens BY6

Energy Technology Data Exchange (ETDEWEB)

Bäuerle, Bettina [Institute of Microbiology, University of Stuttgart, 70569 Stuttgart (Germany); Sandalova, Tatyana; Schneider, Gunter [Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 17177 Stockholm (Sweden); Rieger, Paul-Gerhard, E-mail: pg.rieger@imb.uni-stuttgart.de [Institute of Microbiology, University of Stuttgart, 70569 Stuttgart (Germany)

2006-08-01

This is the first report of the crystallization of an IDS-epimerase from A. tumefaciens BY6 and its l-selenomethionine derivative. The initial degradation of all stereoisomers of the complexing agent iminodisuccinate (IDS) is enabled by an epimerase in the bacterial strain Agrobacterium tumefaciens BY6. This protein was produced in Escherichia coli, purified and crystallized by the hanging-drop vapour-diffusion method. Crystals of IDS-epimerase were obtained under several conditions. The best diffracting crystals were grown in 22% PEG 3350, 0.2 M (NH{sub 4}){sub 2}SO{sub 4} and 0.1 M bis-Tris propane pH 7.2 at 293 K. These crystals belong to the monoclinic space group P2{sub 1}, with unit-cell parameters a = 55.4, b = 104.2, c = 78.6 Å, β = 103.3°, and diffracted to 1.7 Å resolution. They contain two protein molecules per asymmetric unit. In order to solve the structure using the MAD phasing method, crystals of the l-selenomethionine-substituted epimerase were grown in the presence of 20% PEG 3350, 0.2 M Na{sub 2}SO{sub 4} and 0.1 M bis-Tris propane pH 8.5.

Direct production of D-arabinose from D-xylose by a coupling reaction using D-xylose isomerase, D-tagatose 3-epimerase and D-arabinose isomerase.

Science.gov (United States)

Sultana, Ishrat; Mizanur, Rahman Md; Takeshita, Kei; Takada, Goro; Izumori, Ken

2003-01-01

Klebsiella pneumoniae 40bXX, a mutant strain that constitutively produces D-arabinose isomerase (D-AI), was isolated through a series of repeated subcultures from the parent strain on a mineral salt medium supplemented with L-Xylose as the sole carbon source. D-AI could be efficiently immobilized on chitopearl beads. The optimum temperature for the activity of the immobilized enzyme was 40 degrees C and the enzyme was stable up to 50 degrees C. The D-Al was active at pH 10.0 and was stable in the range of pH 6.0-11.0. The enzyme required manganese ions for maximum activity. Three immobilized enzymes, D-xylose isomerase (D-XI), D-tagatose 3-epimerase (D-TE and D-AI were used for the preparation of D-arabinose from D-xylose in a coupling reaction. After completion of the reaction, degradation of D-xylulose was carried out by Saccharomyces cerevisiae. The reaction mixture containing D-Xylose, D-ribulose and the product was then separated by ion exchange column chromatography. After crystallization, the product was checked by HPLC, IR spectroscopy, NMR spectroscopy and optical rotation measurements. Finally, 2.0 g of D-arabinose could be obtained from 5 g of the substrate.

Purification, crystallization and preliminary X-ray crystallographic analysis of diaminopimelate epimerase from Acinetobacter baumannii

International Nuclear Information System (INIS)

Park, Jeong Soon; Lee, Woo Cheol; Song, Jung Hyun; Kim, Seung Il; Lee, Je Chul; Cheong, Chaejoon; Kim, Hye-Yeon

2012-01-01

The crystallization and preliminary X-ray crystallographic analysis of diaminopimelate epimerase from A. baumannii are reported. The meso isomer of diaminopimelate (meso-DAP) is a biosynthetic precursor of l-lysine in bacteria and plants, and is a key component of the peptidoglycan layer in the cell walls of Gram-negative and some Gram-positive bacteria. Diaminopimelate epimerase (DapF) is a pyridoxal-5′-phosphate-independent racemase which catalyses the interconversion of (6S,2S)-2,6-diaminopimelic acid (ll-DAP) and meso-DAP. In this study, DapF from Acinetobacter baumannii was overexpressed in Escherichia coli strain SoluBL21, purified and crystallized using a vapour-diffusion method. A native crystal diffracted to a resolution of 1.9 Å and belonged to space group P3 1 or P3 2 , with unit-cell parameters a = b = 74.91, c = 113.35 Å, α = β = 90, γ = 120°. There were two molecules in the asymmetric unit

Cloning, expression and purification of d-tagatose 3-epimerase gene from Escherichia coli JM109.

Science.gov (United States)

He, Xiaoliang; Zhou, Xiaohui; Yang, Zi; Xu, Le; Yu, Yuxiu; Jia, Lingling; Li, Guoqing

2015-10-01

An unknown d-tagatose 3-epimerase (DTE) containing a IoIE domain was identified and cloned from Escherichia coli. This gene was subcloned into the prokaryotic expression vector pET-15b, and induced by IPTG in E. coli BL21 expression system. Through His-select gel column purification and fast-protein liquid chromatography, highly purified and stable DTE protein was produced. The molecular weight of the DTE protein was estimated to be 29.8kDa. The latest 83 DTE sequences from public database were selected and analyzed by molecular clustering, multi-sequence alignment. DTEs were roughly divided into five categories. Copyright © 2015 Elsevier Inc. All rights reserved.

Effects of rare sugar d-allulose on heat-induced gelation of surimi prepared from marine fish.

Science.gov (United States)

Ogawa, Masahiro; Inoue, Masaki; Hayakawa, Shigeru; O'Charoen, Siwaporn; Ogawa, Makiko

2017-11-01

d-Allulose (Alu), the C3-epimer of d-fructose, is a non-caloric sweetener (0.39 kcal g -1 ) with a suppressive effect on postprandial blood glucose elevation. The aim of this study was to investigate the effects of Alu used as a sweetener and gel improver instead of sucrose on heat-induced gelation of surimi. The puncture test of a heat-induced surimi gel showed that with 50 g kg -1 Alu the gel had 15% and 6% higher gel strength than the corresponding gel with sucrose (Suc) and with sorbitol (Sor), respectively. In addition, Alu-gel had 26% and 25% higher water-holding capacity (WHC) than Suc- and Sor-gel. Heating of myofibrillar protein with Alu, unlike Suc and Sor, facilitated the formation of both disulfide and non-disulfide crosslinks that might be associated with the mechanical properties and WHC of Alu-gel. Alu improves the mechanical properties and WHC of the heat-induced surimi gel. Furthermore, Alu is low in calories compared with Suc (4.0 kcal g -1 ) and Sor (3.0 kcal g -1 ). Thus Alu will be an alternative of Suc or Sor for developing surimi-based products with health benefits. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

3D printing of octacalcium phosphate bone substitutes

Directory of Open Access Journals (Sweden)

Vladimir S. Komlev

2015-06-01

Full Text Available Biocompatible calcium phosphate ceramic grafts are able of supporting new bone formation in appropriate environment. The major limitation of these materials usage for medical implants is the absence of accessible methods for their patient-specific fabrication. 3D printing methodology is an excellent approach to overcome the limitation supporting effective and fast fabrication of individual complex bone substitutes. Here we proposed a relatively simple route for 3D printing of octacalcium phosphates in complexly shaped structures by the combination of inkjet printing with post-treatment methodology. The printed octacalcium phosphate blocks were further implanted in the developed cranial bone defect followed by histological evaluation. The obtained result confirmed the potential of the developed octacalcium phosphates bone substitutes, which allowed 2.5-time reducing of defect’s diameter at 6.5 months in a region where native bone repair is extremely inefficient.

Crystal Structure and Substrate Specificity of D-Galactose-6-Phosphate Isomerase Complexed with Substrates

Science.gov (United States)

Lee, Jung-Kul; Pan, Cheol-Ho

2013-01-01

D-Galactose-6-phosphate isomerase from Lactobacillus rhamnosus (LacAB; EC 5.3.1.26), which is encoded by the tagatose-6-phosphate pathway gene cluster (lacABCD), catalyzes the isomerization of D-galactose-6-phosphate to D-tagatose-6-phosphate during lactose catabolism and is used to produce rare sugars as low-calorie natural sweeteners. The crystal structures of LacAB and its complex with D-tagatose-6-phosphate revealed that LacAB is a homotetramer of LacA and LacB subunits, with a structure similar to that of ribose-5-phosphate isomerase (Rpi). Structurally, LacAB belongs to the RpiB/LacAB superfamily, having a Rossmann-like αβα sandwich fold as has been identified in pentose phosphate isomerase and hexose phosphate isomerase. In contrast to other family members, the LacB subunit also has a unique α7 helix in its C-terminus. One active site is distinctly located at the interface between LacA and LacB, whereas two active sites are present in RpiB. In the structure of the product complex, the phosphate group of D-tagatose-6-phosphate is bound to three arginine residues, including Arg-39, producing a different substrate orientation than that in RpiB, where the substrate binds at Asp-43. Due to the proximity of the Arg-134 residue and backbone Cα of the α6 helix in LacA to the last Asp-172 residue of LacB with a hydrogen bond, a six-carbon sugar-phosphate can bind in the larger pocket of LacAB, compared with RpiB. His-96 in the active site is important for ring opening and substrate orientation, and Cys-65 is essential for the isomerization activity of the enzyme. Two rare sugar substrates, D-psicose and D-ribulose, show optimal binding in the LacAB-substrate complex. These findings were supported by the results of LacA activity assays. PMID:24015281

Crystal structure and substrate specificity of D-galactose-6-phosphate isomerase complexed with substrates.

Directory of Open Access Journals (Sweden)

Woo-Suk Jung

Full Text Available D-Galactose-6-phosphate isomerase from Lactobacillus rhamnosus (LacAB; EC 5.3.1.26, which is encoded by the tagatose-6-phosphate pathway gene cluster (lacABCD, catalyzes the isomerization of D-galactose-6-phosphate to D-tagatose-6-phosphate during lactose catabolism and is used to produce rare sugars as low-calorie natural sweeteners. The crystal structures of LacAB and its complex with D-tagatose-6-phosphate revealed that LacAB is a homotetramer of LacA and LacB subunits, with a structure similar to that of ribose-5-phosphate isomerase (Rpi. Structurally, LacAB belongs to the RpiB/LacAB superfamily, having a Rossmann-like αβα sandwich fold as has been identified in pentose phosphate isomerase and hexose phosphate isomerase. In contrast to other family members, the LacB subunit also has a unique α7 helix in its C-terminus. One active site is distinctly located at the interface between LacA and LacB, whereas two active sites are present in RpiB. In the structure of the product complex, the phosphate group of D-tagatose-6-phosphate is bound to three arginine residues, including Arg-39, producing a different substrate orientation than that in RpiB, where the substrate binds at Asp-43. Due to the proximity of the Arg-134 residue and backbone Cα of the α6 helix in LacA to the last Asp-172 residue of LacB with a hydrogen bond, a six-carbon sugar-phosphate can bind in the larger pocket of LacAB, compared with RpiB. His-96 in the active site is important for ring opening and substrate orientation, and Cys-65 is essential for the isomerization activity of the enzyme. Two rare sugar substrates, D-psicose and D-ribulose, show optimal binding in the LacAB-substrate complex. These findings were supported by the results of LacA activity assays.

Crystal structures of D-psicose 3-epimerase from Clostridium cellulolyticum H10 and its complex with ketohexose sugars.

Science.gov (United States)

Chan, Hsiu-Chien; Zhu, Yueming; Hu, Yumei; Ko, Tzu-Ping; Huang, Chun-Hsiang; Ren, Feifei; Chen, Chun-Chi; Ma, Yanhe; Guo, Rey-Ting; Sun, Yuanxia

2012-02-01

D-psicose 3-epimerase (DPEase) is demonstrated to be useful in the bioproduction of D-psicose, a rare hexose sugar, from D-fructose, found plenty in nature. Clostridium cellulolyticum H10 has recently been identified as a DPEase that can epimerize D-fructose to yield D-psicose with a much higher conversion rate when compared with the conventionally used DTEase. In this study, the crystal structure of the C. cellulolyticum DPEase was determined. The enzyme assembles into a tetramer and each subunit shows a (β/α)(8) TIM barrel fold with a Mn(2+) metal ion in the active site. Additional crystal structures of the enzyme in complex with substrates/products (D-psicose, D-fructose, D-tagatose and D-sorbose) were also determined. From the complex structures of C. cellulolyticum DPEase with D-psicose and D-fructose, the enzyme has much more interactions with D-psicose than D-fructose by forming more hydrogen bonds between the substrate and the active site residues. Accordingly, based on these ketohexose-bound complex structures, a C3-O3 proton-exchange mechanism for the conversion between D-psicose and D-fructose is proposed here. These results provide a clear idea for the deprotonation/protonation roles of E150 and E244 in catalysis.

Synthesis and modifications of heterocyclic derivatives of D-arabinose: potential inhibitors of glucose-6-phosphate isomerase and glucosamine-6-phosphate synthase

International Nuclear Information System (INIS)

Viana, Renato Marcio Ribeiro; Prado, Maria Auxiliadora Fontes; Alves, Ricardo Jose

2008-01-01

The synthesis of -5-(D-arabino-1,2,3,4-tetrahydroxybutyl)tetrazole and -2-(d-arabino-1,2,3,4-tetra-acetoxybutyl)-5-methyl-1,3,4-oxadiazole from d-arabinose is described. Attempts at removing the protecting groups of the oxadiazole derivative were unsuccessful, leading to products resulting from the opening of the oxadiazole ring. The unprotected tetrazole derivative was selectively phosphorylated at the primary hydroxyl group with diethyl phosphoryl chloride. The resulting 5-[d-arabino-4-(diethylphosphoryloxy)-1,2,3-trihydroxybutyl]tetrazole is a protected form of a potential inhibitor of the enzymes glucose-6-phosphate isomerase and glucosamine synthase. (author)

Sensitive, specific radioisotope assay for L-glutamine-D-fructose-6- phosphat aminotransferase

International Nuclear Information System (INIS)

Callahan, M.; Tourian, A.; Hung, W.Y.

1981-01-01

A sensitive and specific radioassay for L-glutamine-D-fructose-6-phosphate aminotransferase (EC 5.3.1.19) activity is presented. Picomoles of product are measurable, and the assay can be applied to systems having limited quantities of available protein, particularly in extracts of either cell or organ cultures. The assay is at least 10,000 times more sensitive under K 1 concentrations of fructose 6-phosphate than the modified Elson-Morgan colorimetric assay and 20 times more sensitive under saturating conditions of fructose 6-phosphate. As little as 0.5 μg of cell-extract protein will yield measurable product. In contrast, 280 μg of crude-extract protein from colon is required with the modified Elson-Morgan colorimetric assay

Genetic Evidence for the Physiological Significance of the d-Tagatose 6-Phosphate Pathway of Lactose and d-Galactose Degradation in Staphylococcus aureus1

Science.gov (United States)

Bissett, Donald L.; Anderson, Richard L.

1974-01-01

Mutants of Staphylococcus aureus were isolated which were unable to utilize d-galactose or lactose, but which were able to utilize all other carbohydrates tested. Growth of the mutants on a peptone-containing medium was inhibited by d-galactose. Of those mutants selected for further study, one (tagI2) was missing d-galactose 6-phosphate isomerase, one (tagK3) was missing d-tagatose 6-phosphate kinase, and one (tagA4) was missing d-tagatose 1, 6-diphosphate aldolase. Each of these mutants accumulated the substrate of the missing enzyme intracellularly. Spontaneous revertants of each of the mutants simultaneously regained their ability to utilize d-galactose and lactose, lost their sensitivity to d-galactose, regained the missing enzymatic activities, and no longer accumulated intermediates of the d-tagatose 6-phosphate pathway. These data support our previous contention that the physiologically significant route for the metabolism of d-galactose and the d-galactosyl moiety of lactose in S. aureus is the d-tagatose 6-phosphate pathway. Furthermore, a mutant constitutive for all three enzymes of this pathway was isolated, indicating that the products of the tagI, tagK, and tagA genes are under common genetic control. This conclusion was supported by the demonstration that d-galactose 6-phosphate isomerase, d-tagatose 6-phosphate kinase, and d-tagatose 1, 6-diphosphate aldolase are coordinately induced in the parental strain. PMID:4277494

Overexpression of an alfalfa GDP-mannose 3, 5-epimerase gene enhances acid, drought and salt tolerance in transgenic Arabidopsis by increasing ascorbate accumulation.

Science.gov (United States)

Ma, Lichao; Wang, Yanrong; Liu, Wenxian; Liu, Zhipeng

2014-11-01

GDP-mannose 3', 5'-epimerase (GME) catalyses the conversion of GDP-D-mannose to GDP-L-galactose, an important step in the ascorbic acid (ascorbic acid) biosynthetic pathway in higher plants. In this study, a novel cDNA fragment (MsGME) encoding a GME protein was isolated and characterised from alfalfa (Medicago sativa). An expression analysis confirmed that MsGME expression was induced by salinity, PEG and acidity stresses. MsGME overexpression in Arabidopsis enhanced tolerance of the transgenic plants to salt, drought and acid. Real-time PCR analysis revealed that the transcript levels of GDP-D-mannose pyrophosphorylase (GMP), L-galactose-phosphate 1-P phosphatase (GP) and GDP-L-galactose phosphorylase (GGP) were increased in transgenic Arabidopsis (T3 generation). Moreover, the ascorbate content was increased in transgenic Arabidopsis. Our results suggest that MsGME can effectively enhance tolerance of transgenic Arabidopsis to acid, drought and salt by increasing ascorbate accumulation.

D-glucose-6-phosphate dehydrogenase (Entner-Doudoroff enzyme) from Pseudomonas fluorescens

International Nuclear Information System (INIS)

Lessmann, D.; Schimz, K.L.; Kurz, G.

1975-01-01

The existence of two different D-glucose-6-phosphate dehydrogenases in Pseudomonas fluorescens has been demonstrated. Based on their different specificity and their different metabolic regulation one enzyme is appointed to the Entner-Doudoroff pathway and the other to the hexose monophosphate pathway. A procedure is described for the isolation of that D-glucose-6-phosphate dehydrogenase which forms part of the Entner-Doudoroff pathway (Entner-Doudoroff enzyme). A 950-fold purification was achieved with an overall yield of 44%. The final preparation, having a specific activity of about 300μmol NADH formed per min per mg protein, was shown to be homogeneous. The molecular weight of the Entner-Doudoroff enzyme has been determined to be 220,000 by gel permeation chromatography, and that of the other enzyme (Zwischenferment) has been shown to be 265,000. The pI of the Entner-Doudoroff enzyme has been shown to be 5.24 and that of the Zwischenferment 4.27. The Entner-Doudoroff enzyme is stable in the range of pH 6 to 10.5 and shows its maximal acivity at pH 8.9. The Entner-Doudoroff enzyme showed specificity for NAD + as well as for NADP + and exhibited homotropic effects for D-glucose 6-phosphate. It is inhibited by ATP which acts as a negative allosteric effector. Other nucleoside triphosphates as well as ADP are also inhibitory. The enzyme catalyzes the transfer of the axial hydrogen at carbon-1 of β-D-glucopyranose 6-phosphate to the si face of carbon-4 of the nicotinamide ring and must be classified as B-side stereospecific dehydrogenase. (orig.) [de

An integrated bio-process for production of functional biomolecules utilizing raw and by-products from dairy and sugarcane industries.

Science.gov (United States)

Lata, Kusum; Sharma, Manisha; Patel, Satya Narayan; Sangwan, Rajender S; Singh, Sudhir P

2018-04-21

The study investigated an integrated bioprocessing of raw and by-products from sugarcane and dairy industries for production of non-digestible prebiotic and functional ingredients. The low-priced feedstock, whey, molasses, table sugar, jaggery, etc., were subjected to transglucosylation reactions catalyzed by dextransucrase from Leuconostoc mesenteroides MTCC 10508. HPLC analysis approximated production of about 11-14 g L -1 trisaccharide i.e. 2-α-D-glucopyranosyl-lactose (4-galactosyl-kojibiose) from the feedstock prepared from table sugar, jaggery, cane molasses and liquid whey, containing about 30 g L -1 sucrose and lactose each. The trisaccharide was hydrolysed into the prebiotic disaccharide, kojibiose, by employing recombinant β-galactosidase from Escherichia coli. The enzyme β-galactosidase achieved about 90% conversion of 2-α-D-glucopyranosyl-lactose into kojibiose. The D-fructose generated by catalytic reactions of dextransucrase was targeted for catalytic transformation into rare sugar, D-allulose (or D-psicose), by treating the samples with Smt3-D-psicose 3-epimerase. The catalytic reactions resulted in the conversion of ~ 25% D-fructose to D-allulose. These bioactive compounds are known to exert a plethora of benefits to human health, and therefore, are preferred ingredients for making functional foods.

Betaine Phosphate (CH3)3N+CH2COO-.H3PO4 Modification Using D2O

International Nuclear Information System (INIS)

Saryati; Ridwan; Deswita; Sugiantoro, Sugik

2002-01-01

Betaine fosfate (CH 3 ) 3 N + CH 2 COO - .H 3 PO 4 modification by using D 2 O has been studied. This modification was carried out by slowly evaporation the saturated Betaine phosphat in the D 2 O solution in the dry box at 40 o C, until the dry crystal were formed. Based on the NMR data, can be concluded that the exchange process with D has been runed well and Betaine phosphate-D (CH 3 ) 3 N + CH 2 COO - .H 3 PO 4 has been resulted. From the X-ray diffraction pattern data can be concluded that there are a deference in the crystal structure between Betaine phosphate and Betaine phosphate modification result. From the Differential Scanning Colorimeter (DSC) diagram at the range temperature from 30 o C to 250 o C, can be shown that the Betaine phosphate-H has two endothermic transition phase, at 99 o C with a very little adsorbed calor and at 221.50 o C with -26.75 cal/g. Modified Betaine phosphate has also two endothermic transition phase, at 99.86 o C with -1.94 cal/g and at 171.01 o C with -3.48 cal/g. It can be conclosed that the D atom substitution on the H atoms in Betaine phosphate, to change the crystal and the endothermic fase temperature and energy

Galactose Epimerase Deficiency: Expanding the Phenotype

NARCIS (Netherlands)

Dias Costa, Filipa; Ferdinandusse, Sacha; Pinto, Carla; Dias, Andrea; Keldermans, Liesbeth; Quelhas, Dulce; Matthijs, Gert; Mooijer, Petra A.; Diogo, Luísa; Jaeken, Jaak; Garcia, Paula

2017-01-01

Galactose epimerase deficiency is an inborn error of metabolism due to uridine diphosphate-galactose-4'-epimerase (GALE) deficiency. We report the clinical presentation, genetic and biochemical studies in two siblings with generalized GALE deficiency.Patient 1: The first child was born with a

Thermodynamics of the hydrolysis reactions of α-D-galactose 1-phosphate, sn-glycerol 3-phosphate, 4-nitrophenyl phosphate, phosphocreatine, and 3-phospho-D-glycerate

International Nuclear Information System (INIS)

Goldberg, Robert N.; Lang, Brian E.; Lo, Catherine; Ross, David J.; Tewari, Yadu B.

2009-01-01

Microcalorimetry, high-performance liquid chromatography (h.p.l.c.), and an enzymatic assay have been used to conduct a thermodynamic investigation of five phosphate hydrolysis reactions: {α-D-galactose 1-phosphate(aq) + H 2 O(l) = D-galactose(aq) + orthophosphate(aq)} (1), {sn-glycerol 3-phosphate(aq) + H 2 O(l) = glycerol(aq) + orthophosphate(aq)} (2), {4-nitrophenyl phosphate(aq) + H 2 O(l) = 4-nitrophenol(aq) + orthophosphate(aq)} (3), {phosphocreatine(aq) + H 2 O(l) = creatine(aq) + orthophosphate(aq)} (4), and {3-phospho-D-glycerate(aq) + H 2 O(l) = D-glycerate(aq) + orthophosphate(aq)} (5). Calorimetrically determined enthalpies of reaction Δ r H(cal) were measured for reactions (1)-(5) and the apparent equilibrium constant K' was measured for reaction (2). The pKs and standard enthalpies of reaction Δ r H 0 for the H + and Mg 2+ binding reactions of the reactants and products in the aforementioned reactions were obtained either from the literature or by estimation. A chemical equilibrium model was then used to calculate standard equilibrium constants K and standard enthalpies of reaction Δ r H 0 for chemical reference reactions that correspond to the overall biochemical reactions that were studied experimentally. Property values from the literature and thermodynamic network calculations were used to obtain values of the equilibrium constants for the chemical reference reactions that correspond to the overall biochemical reactions (1). These values were compared with other results from the literature and also correlated with structural features. The results obtained in this study can be used in the chemical equilibrium model to calculate values of K', the standard apparent Gibbs free energy changes Δ r G '0 , the standard apparent enthalpy changes Δ r H '0 , changes in binding of the proton Δ r N(H + ), and the position of equilibrium for the overall biochemical reactions considered in this study over a reasonably wide range of temperature, pH, p

Crystallization and preliminary X-ray diffraction analysis of diaminopimelate epimerase from Escherichia coli

International Nuclear Information System (INIS)

Hor, Lilian; Dobson, Renwick C. J.; Dogovski, Con; Hutton, Craig A.; Perugini, Matthew A.

2009-01-01

Diaminopimelate (DAP) epimerase, an enzyme in the lysine-biosynthetic pathway, is a promising target for antibiotic development against pathogenic bacteria. Here, the cloning, expression, purification, crystallization and preliminary diffraction analysis of DAP epimerase from E. coli are reported. Diaminopimelate (DAP) epimerase (EC 5.1.1.7) catalyzes the penultimate step of lysine biosynthesis in bacteria and plants, converting l,l-diaminopimelate to meso-diaminopimelate. Here, the cloning, expression, purification, crystallization and preliminary X-ray diffraction analysis of DAP epimerase from Escherichia coli are presented. Crystals were obtained in space group P4 1 2 1 2 and diffracted to 2.0 Å resolution, with unit-cell parameters a = b = 89.4, c = 179.6 Å. Molecular replacement was conducted using Bacillus anthracis DAP epimerase as a search model and showed the presence of two molecules in the asymmetric unit, with an initial R free of 0.456 and R work of 0.416

Plasmid linkage of the D-tagatose 6-phosphate pathway in Streptococcus lactis: effect on lactose and galactose metabolism.

Science.gov (United States)

Crow, V L; Davey, G P; Pearce, L E; Thomas, T D

1983-01-01

The three enzymes of the D-tagatose 6-phosphate pathway (galactose 6-phosphate isomerase, D-tagatose 6-phosphate kinase, and tagatose 1,6-diphosphate aldolase) were absent in lactose-negative (Lac-) derivatives of Streptococcus lactis C10, H1, and 133 grown on galactose. The lactose phosphoenolpyruvate-dependent phosphotransferase system and phospho-beta-galactosidase activities were also absent in Lac- derivatives of strains H1 and 133 and were low (possibly absent) in C10 Lac-. In all three Lac- derivatives, low galactose phosphotransferase system activity was found. On galactose, Lac- derivatives grew more slowly (presumably using the Leloir pathway) than the wild-type strains and accumulated high intracellular concentrations of galactose 6-phosphate (up to 49 mM); no intracellular tagatose 1,6-diphosphate was detected. The data suggest that the Lac phenotype is plasmid linked in the three strains studied, with the evidence being more substantial for strain H1. A Lac- derivative of H1 contained a single plasmid (33 megadaltons) which was absent from the Lac- mutant. We suggest that the genes linked to the lactose plasmid in S. lactis are more numerous than previously envisaged, coding for all of the enzymes involved in lactose metabolism from initial transport to the formation of triose phosphates via the D-tagatose 6-phosphate pathway. Images PMID:6294064

Highly efficient production of rare sugars D-psicose and L-tagatose by two engineered D-tagatose epimerases.

Science.gov (United States)

Bosshart, Andreas; Wagner, Nina; Lei, Lei; Panke, Sven; Bechtold, Matthias

2016-02-01

Rare sugars are monosaccharides that do not occur in nature in large amounts. However, many of them demonstrate high potential as low-calorie sweetener, chiral building blocks or active pharmaceutical ingredients. Their production by enzymatic means from broadly abundant epimers is an attractive alternative to synthesis by traditional organic chemical means, but often suffers from low space-time yields and high enzyme costs due to rapid enzyme degradation. Here we describe the detailed characterization of two variants of d-tagatose epimerase under operational conditions that were engineered for high stability and high catalytic activity towards the epimerization of d-fructose to d-psicose and l-sorbose to l-tagatose, respectively. A variant optimized for the production of d-psicose showed a very high total turnover number (TTN) of up to 10(8) catalytic events over a catalyst's lifetime, determined under operational conditions at high temperatures in an enzyme-membrane reactor (EMR). Maximum space-time yields as high as 10.6 kg L(-1) d(-1) were obtained with a small laboratory-scale EMR, indicating excellent performance. A variant optimized for the production of l-tagatose performed less stable in the same setting, but still showed a very good TTN of 5.8 × 10(5) and space-time yields of up to 478 g L(-1) d(-1) . Together, these results confirm that large-scale enzymatic access to rare sugars is feasible. © 2015 Wiley Periodicals, Inc.

Crystallization and preliminary X-ray diffraction analysis of the putative aldose 1-epimerase YeaD from Escherichia coli

International Nuclear Information System (INIS)

You, Weijie; Qiu, Xiaoting; Zhang, Yujie; Ma, Jinming; Gao, Yongxiang; Zhang, Xiao; Niu, Liwen; Teng, Maikun

2010-01-01

The putative aldose 1-epimerase YeaD from Escherichia coli was crystallized and diffraction data were collected to a resolution of 1.9 Å. Escherichia coli YeaD (ecYeaD) is suggested to be a member of the galactose mutarotase-like superfamily. Galactose mutarotase is an enzyme that converts α-galactose to β-galactose. The known structures of these galactose mutarotase-like proteins are similar to those of galactose mutarotases, with the catalytic residues being conserved, but there are some differences between them in the substrate-binding pocket. In order to reveal the specificity of ecYeaD, a three-dimensional structure is essential. Full-length ecYeaD with an additional 6×His tag at the C-terminus was crystallized by the hanging-drop vapour-diffusion method using polyethylene glycol 4000 as a precipitant at 283 K. An X-ray diffraction data set was collected to a resolution of 1.9 Å from a single flash-cooled crystal that belonged to space group P2 1 2 1 2 1

Reaction of uridine diphosphate galactose 4-epimerase with a suicide inactivator

International Nuclear Information System (INIS)

Flentke, G.R.; Frey, P.A.

1990-01-01

UDPgalactose 4-epimerase from Escherichia coli is rapidly inactivated by the compounds uridine 5'-diphosphate chloroacetol (UDC) and uridine 5'-diphosphate bromoacetol (UCB). Both UDC and UDB inactivate the enzyme in neutral solution concomitant with the appearance of chromophores absorbing maximally at 325 and 328 nm, respectively. The reaction of UDC with the enzyme follows saturation kinetics characterized by a K D of 0.110 mM and k inact of 0.84 min -1 at pH 8.5 and ionic strength 0.2 M. The inactivation by UDC is competitively inhibited by competitive inhibitors of UDPgalactose 4-epimerase, and it is accompanied by the tight but noncovalent binding of UDC to the enzyme in a stoichiometry of 1 mol of UDC/mol of enzyme dimer, corresponding to 1 mol of UDC/mol of enzyme-bound NAD + . The inactivation of epimerase by uridine 5'-diphosphate [ 2 H 2 ]chloroacetol proceeds with a primary kinetic isotope effect (k H /k D ) of 1.4. The inactivation mechanism is proposed to involve a minimum of three steps: (a) reversible binding of UDC to the active site of UDPgalactose 4-epimerase; (b) enolization of the chloroacetol moiety of enzyme-bound UDC, catalyzed by an enzymic general base at the active site; (c) alkylation of the nicotinamide ring of NAD + at the active site by the chloroacetol enolate. The resulting adduct between UDC and NAD + is proposed to be the chromophore with λ max at 325 nm. The enzymic general base required to facilitate proton transfer in redox catalysis by this enzyme may be the general base that facilitates enolization of the chloroacetol moiety of UDC in the inactivation reaction

Novel mode of inhibition by D-tagatose 6-phosphate through a Heyns rearrangement in the active site of transaldolase B variants.

Science.gov (United States)

Stellmacher, Lena; Sandalova, Tatyana; Schneider, Sarah; Schneider, Gunter; Sprenger, Georg A; Samland, Anne K

2016-04-01

Transaldolase B (TalB) and D-fructose-6-phosphate aldolase A (FSAA) from Escherichia coli are C-C bond-forming enzymes. Using kinetic inhibition studies and mass spectrometry, it is shown that enzyme variants of FSAA and TalB that exhibit D-fructose-6-phosphate aldolase activity are inhibited covalently and irreversibly by D-tagatose 6-phosphate (D-T6P), whereas no inhibition was observed for wild-type transaldolase B from E. coli. The crystal structure of the variant TalB(F178Y) with bound sugar phosphate was solved to a resolution of 1.46 Å and revealed a novel mode of covalent inhibition. The sugar is bound covalently via its C2 atom to the ℇ-NH2 group of the active-site residue Lys132. It is neither bound in the open-chain form nor as the closed-ring form of D-T6P, but has been converted to β-D-galactofuranose 6-phosphate (D-G6P), a five-membered ring structure. The furanose ring of the covalent adduct is formed via a Heyns rearrangement and subsequent hemiacetal formation. This reaction is facilitated by Tyr178, which is proposed to act as acid-base catalyst. The crystal structure of the inhibitor complex is compared with the structure of the Schiff-base intermediate of TalB(E96Q) formed with the substrate D-fructose 6-phosphate determined to a resolution of 2.20 Å. This comparison highlights the differences in stereochemistry at the C4 atom of the ligand as an essential determinant for the formation of the inhibitor adduct in the active site of the enzyme.

Hydrocortisone and Vitamin D3 stimulation of 32Psub(i)-phosphate accumulation by organ-cultured chick embryo duodenum

International Nuclear Information System (INIS)

Corradino, R.A.

1979-01-01

Either vitamin D 3 (or 1 α,25-(OH) 2 -D 3 ) or hydrocortisone (HC) stimulated phosphate accumulation by organ-cultured embryonic chick duodenum. In combination, these two steroids stimulated phosphate uptake synergistically. Phosphate accumulation appeared to be independent of other vitamin D 3 -stimulated processes: CaBP concentration, cAMP concentration, or alkaline phosphataseactivity. L-phenylalanine, a reported alkaline phosphate inhibitor, when added to the culture medium progressively inhibited either D 3 - or HC-stimulated phosphate uptake subsequent to culture, but did not inhibit the synergistic action under these conditions L-phenylalanine had no consistent effect on alkaline phosphotase activity but unexpectedly, greatly inhibited vitamin D 3 - stimulated CaBP concentration, but only in the absence of HC. Some limited suggestion of an intestinal phosphoprotein sensitve to either vitamin D 3 or HC was observed. (orig.) [de

Heterogeneity of d-glucuronyl C5-epimerase expression and epigenetic regulation in prostate cancer

International Nuclear Information System (INIS)

Prudnikova, Tatiana Y; Soulitzis, Nikolaos; Kutsenko, Olesya S; Mostovich, Lyudmila A; Haraldson, Klas; Ernberg, Ingemar; Kashuba, Vladimir I; Spandidos, Demetrios A; Zabarovsky, Eugene R; Grigorieva, Elvira V

2013-01-01

Heparansulfate proteoglycans (HSPG) play an important role in cell–cell and cell–matrix interactions and signaling, and one of the key enzymes in heparansulfate biosynthesis is d-glucuronyl C5-epimerase (GLCE). A tumor suppressor function has been demonstrated for GLCE in breast and lung carcinogenesis; however, no data are available as to the expression and regulation of the gene in prostate cancer. In this study, decreased GLCE expression was observed in 10% of benign prostate hyperplasia (BPH) tissues and 53% of prostate tumors, and increased GLCE mRNA levels were detected in 49% of BPH tissues and 21% of tumors. Statistical analysis showed a positive correlation between increased GLCE expression and Gleason score, TNM staging, and prostate-specific antigen (PSA) level in the prostate tumors (Pearson correlation coefficients GLCE/Gleason = 0.56, P < 0.05; GLCE/TNM = 0.62, P < 0.05; and GLCE/PSA = 0.88, P < 0.01), suggesting GLCE as a candidate molecular marker for advanced prostate cancer. Immunohistochemical analysis revealed an intratumoral heterogeneity of GLCE protein levels both in BPH and prostate cancer cells, resulting in a mixed population of GLCE-expressing and nonexpressing epithelial cells in vivo. A model experiment on normal (PNT2) and prostate cancer (LNCaP, PC3, DU145) cell lines in vitro showed a 1.5- to 2.5-fold difference in GLCE expression levels between the cancer cell lines and an overall decrease in GLCE expression in cancer cells. Methyl-specific polymerase chain reaction (PCR), bisulfite sequencing, and deoxy-azacytidin (aza-dC) treatment identified differential GLCE promoter methylation (LNCaP 70–72%, PC3 32–35%, DU145, and PNT2 no methylation), which seems to contribute to heterogeneous GLCE expression in prostate tumors. The obtained results reveal the complex deregulation of GLCE expression in prostatic diseases compared with normal prostate tissue and suggest that GLCE may be used as a potential model to study the functional

TM0416, a Hyperthermophilic Promiscuous Nonphosphorylated Sugar Isomerase, Catalyzes Various C5 and C6 Epimerization Reactions.

Science.gov (United States)

Shin, Sun-Mi; Cao, Thinh-Phat; Choi, Jin Myung; Kim, Seong-Bo; Lee, Sang-Jae; Lee, Sung Haeng; Lee, Dong-Woo

2017-05-15

There is currently little information on nonphosphorylated sugar epimerases, which are of potential interest for producing rare sugars. We found a gene (the TM0416 gene) encoding a putative d-tagatose-3-epimerase-related protein from the hyperthermophilic bacterium Thermotoga maritima We overexpressed the TM0416 gene in Escherichia coli and purified the resulting recombinant protein for detailed characterization. Amino acid sequence alignment and a structural similarity search revealed that TM0416 is a putative nonphosphorylated sugar epimerase. The recombinant enzyme exhibited maximal C-3 epimerization of l-ribulose to l-xylulose at ∼80°C and pH 7 in the presence of 1 mM Mn 2+ In addition, this enzyme showed unusually high activity for the epimerization of d-tagatose to d-sorbose, with a conversion yield of 20% after 6 h at 80°C. Remarkably, the enzyme catalyzed the isomerization of d-erythrose or d-threose to d-erythrulose significantly, with conversion yields of 71% and 54.5%, respectively, after 6 h at 80°C at pH 7. To further investigate the substrate specificity of TM0416, we determined its crystal structures in complex with divalent metal ions and l-erythrulose at resolutions of 1.5 and 1.6 Å. Detailed inspection of the structural features and biochemical data clearly demonstrated that this metalloenzyme, with a freely accessible substrate-binding site and neighboring hydrophobic residues, exhibits different and promiscuous substrate preferences, compared with its mesophilic counterparts. Therefore, this study suggests that TM0416 can be functionally classified as a novel type of l-ribulose 3-epimerase (R3E) with d-erythrose isomerase activity. IMPORTANCE Rare sugars, which occur naturally in small amounts, have attracted considerable attention in the food and drug industries. However, there is little information on nonphosphorylated sugar epimerases, which might potentially be applied for the production of rare sugars. This study describes the

Discovery of a Dipeptide Epimerase Enzymatic Function Guided by Homology Modeling and Virtual Screening

Energy Technology Data Exchange (ETDEWEB)

Kalyanaraman, C.; Imker, H; Fedorov, A; Fedorov, E; Glasner, M; Babbitt, P; Almo, S; Gerlt, J; Jacobson, M

2008-01-01

We have developed a computational approach to aid the assignment of enzymatic function for uncharacterized proteins that uses homology modeling to predict the structure of the binding site and in silico docking to identify potential substrates. We apply this method to proteins in the functionally diverse enolase superfamily that are homologous to the characterized L-Ala-D/L-Glu epimerase from Bacillus subtilis. In particular, a protein from Thermotoga martima was predicted to have different substrate specificity, which suggests that it has a different, but as yet unknown, biological function. This prediction was experimentally confirmed, resulting in the assignment of epimerase activity for L-Ala-D/L-Phe, L-Ala-D/L-Tyr, and L-Ala-D/L-His, whereas the enzyme is annotated incorrectly in GenBank as muconate cycloisomerase. Subsequently, crystal structures of the enzyme were determined in complex with three substrates, showing close agreement with the computational models and revealing the structural basis for the observed substrate selectivity.

Structure, kinetic characterization and subcellular localization of the two ribulose 5-phosphate epimerase isoenzymes from Trypanosoma cruzi.

Directory of Open Access Journals (Sweden)

Soledad Natalia Gonzalez

Full Text Available The enzyme of the pentose phosphate pathway (PPP ribulose-5-phosphate-epimerase (RPE is encoded by two genes present in the genome of Trypanosoma cruzi CL Brener clone: TcRPE1 and TcRPE2. Despite high sequence similarity at the amino acid residue level, the recombinant isoenzymes show a strikingly different kinetics. Whereas TcRPE2 follows a typical michaelian behavior, TcRPE1 shows a complex kinetic pattern, displaying a biphasic curve, suggesting the coexistence of -at least- two kinetically different molecular forms. Regarding the subcellular localization in epimastigotes, whereas TcRPE1 is a cytosolic enzyme, TcRPE2 is localized in glycosomes. To our knowledge, TcRPE2 is the first PPP isoenzyme that is exclusively localized in glycosomes. Over-expression of TcRPE1, but not of TcRPE2, significantly reduces the parasite doubling time in vitro, as compared with wild type epimastigotes. Both TcRPEs represent single domain proteins exhibiting the classical α/β TIM-barrel fold, as expected for enzymes with this activity. With regard to the architecture of the active site, all the important amino acid residues for catalysis -with the exception of M58- are also present in both TcRPEs models. The superimposition of the binding pocket of both isoenzyme models shows that they adopt essentially identical positions in the active site with a residue specific RMSD < 2Å, with the sole exception of S12, which displays a large deviation (residue specific RMSD: 11.07 Å. Studies on the quaternary arrangement of these isoenzymes reveal that both are present in a mixture of various oligomeric species made up of an even number of molecules, probably pointing to the dimer as their minimal functional unit. This multiplicity of oligomeric species has not been reported for any of the other RPEs studied so far and it might bear implications for the regulation of TcRPEs activity, although further investigation will be necessary to unravel the physiological

Crystal structure of β-d,l-psicose

Directory of Open Access Journals (Sweden)

Tomohiko Ishii

2015-05-01

Full Text Available The title compound, C6H12O6, a C-3 position epimer of fructose, was crystallized from an aqueous solution of equimolar mixture of d- and l-psicose (1,3,4,5,6-pentahydroxyhexan-2-one, ribo-2-hexulose, allulose, and it was confirmed that d-psicose (or l-psicose formed β-pyranose with a 2C5 (or 5C2 conformation. In the crystal, an O—H...O hydrogen bond between the hydroxy groups at the C-3 and C-2 positions connects homochiral molecules into a column along the b axis. The columns are linked by other O—H...O hydrogen bonds between d- and l-psicose molecules, forming a three-dimensional network. An intramolecular O—H...O hydrogen bond is also observed. The cell volume of racemic β-d,l-psicose [763.21 (6 Å3] is almost the same as that of chiral β-d-psicose [753.06 Å3].

Studies of alkaline mediated phosphate migration in synthetic phosphoethanolamine l-glycero-d-manno-heptoside derivatives

International Nuclear Information System (INIS)

Stewart, A.; Martin, A.; Richards, J.C.; Bernlind, C.; Oscarson, S.; Schweda, E.K.H.

1998-01-01

Synthetic 2-, 3-, 4- and 6-monophosphate derivatives of methyl α-d-mannopyranosides, the 4-, 6- and 7-monophosphate derivatives of methyl l-glycero-α-d-manno-heptopyranosides and the corresponding phosphoethanolamine derivatives and a 6,7-cyclic phosphate analogue of methyl l-glycero-α-d-manno-heptopyranoside were used to study phosphate migration and hydrolysis when subjected to strong alkaline conditions (4 M KOH, 120 C, 18 h). The resulting products were analyzed by 1 H NMR spectroscopy and electrospray mass spectrometry. It was found that phosphate substituents were stable under these conditions and neither migration nor hydrolysis was observed except for the heptose 7-phosphate, which gave a substantial amount of phosphate hydrolysis. In phosphoethanolamine-substituted compounds migration to adjacent positions with concomitant loss of ethanolamine was found together with hydrolysis. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

D-6-Deoxy-myo-inositol 1,3,4,5-tetrakisphosphate, a mimic of D-myo-inositol 1,3,4,5-tetrakisphosphate: biological activity and pH-dependent conformational properties

International Nuclear Information System (INIS)

Horne, Graeme; Maechling, Clarisse; Fleig, Andrea; Hirata, Masato; Penner, Reinhold; Spiess, Bernard; Potter, Barry V.L.

2004-01-01

D-6-Deoxy-myo-inositol 1,3,4,5-tetrakisphosphate [D-6-deoxy-Ins(1,3,4,5)P 4 ] 3 is a novel deoxygenated analogue of D-myo-inositol 1,3,4,5-tetrakisphosphate [Ins(1,3,4,5)P 4 ] 2, a central and enigmatic molecule in the polyphosphoinositide pathway of cellular signalling. D-6-Deoxy-Ins(1,3,4,5)P 4 is a moderate inhibitor of Ins(1,4,5)P 3 5-phosphatase [1.8 μM] compared to Ins(1,3,4,5)P 4 [0.15 μM] and similar to that of L-Ins(1,3,4,5)P 4 [1.8 μM]. In displacement of [ 3 H] Ins(1,4,5)P 3 from the rat cerebellar Ins(1,4,5)P 3 receptor, while slightly weaker [IC 50 =800 nM] than that of D-Ins(1,3,4,5)P 4 [IC 50 =220 nM], 3 is less markedly different and again similar to that of L-Ins(1,3,4,5)P 4 [IC 50 =660 nM]. 3 is an activator of I CRAC when inward currents are measured in RBL-2H3-M1 cells using patch-clamp electrophysiological techniques with a facilitation curve different to that of Ins(1,3,4,5)P 4 . Physicochemical properties were studied by potentiometric 31 P and 1 H NMR titrations and were similar to those of Ins(1,3,4,5)P 4 apart from the observation of a biphasic titration curve for the P1 phosphate group. A novel vicinal phosphate charge-induced conformational change of the inositol ring above pH 10 was observed for D-6-deoxy-Ins(1,3,4,5)P 4 that would normally be hindered because of the central stabilising role played by the 6-OH group in Ins(1,3,4,5)P 4 . We conclude that the 6-OH group in Ins(1,3,4,5)P 4 is crucial for its physicochemical behaviour and biological properties of this key inositol phosphate

Structural Diversity Within the Mononuclear and Binuclear Active Sites of N-Acetyl-D-Glucosamine-6-Phosphate Deacetylase

Energy Technology Data Exchange (ETDEWEB)

Hall,R.; Brown, S.; Fedorov, A.; Fedorov, E.; Xu, C.; Babbitt, P.; Almo, S.; Raushel, F.

2007-01-01

NagA catalyzes the hydrolysis of N-acetyl-D-glucosamine-6-phosphate to D-glucosamine-6-phosphate and acetate. X-ray crystal structures of NagA from Escherichia coli were determined to establish the number and ligation scheme for the binding of zinc to the active site and to elucidate the molecular interactions between the protein and substrate. The three-dimensional structures of the apo-NagA, Zn-NagA, and the D273N mutant enzyme in the presence of a tight-binding N-methylhydroxyphosphinyl-D-glucosamine-6-phosphate inhibitor were determined. The structure of the Zn-NagA confirms that this enzyme binds a single divalent cation at the beta-position in the active site via ligation to Glu-131, His-195, and His-216. A water molecule completes the ligation shell, which is also in position to be hydrogen bonded to Asp-273. In the structure of NagA bound to the tight binding inhibitor that mimics the tetrahedral intermediate, the methyl phosphonate moiety has displaced the hydrolytic water molecule and is directly coordinated to the zinc within the active site. The side chain of Asp-273 is positioned to activate the hydrolytic water molecule via general base catalysis and to deliver this proton to the amino group upon cleavage of the amide bond of the substrate. His-143 is positioned to help polarize the carbonyl group of the substrate in conjunction with Lewis acid catalysis by the bound zinc. The inhibitor is bound in the {alpha}-configuration at the anomeric carbon through a hydrogen bonding interaction of the hydroxyl group at C-1 with the side chain of His-251. The phosphate group of the inhibitor attached to the hydroxyl at C-6 is ion paired with Arg-227 from the adjacent subunit. NagA from Thermotoga maritima was shown to require a single divalent cation for full catalytic activity.

GDP-D-mannose epimerase regulates male gametophyte development, plant growth and leaf senescence in Arabidopsis.

Science.gov (United States)

Qi, Tiancong; Liu, Zhipeng; Fan, Meng; Chen, Yan; Tian, Haixia; Wu, Dewei; Gao, Hua; Ren, Chunmei; Song, Susheng; Xie, Daoxin

2017-09-04

Plant GDP-D-mannose epimerase (GME) converts GDP-D-mannose to GDP-L-galactose, a precursor of both L-ascorbate (vitamin C) and cell wall polysaccharides. However, the genetic functions of GME in Arabidopsis are unclear. In this study, we found that mutations in Arabidopsis GME affect pollen germination, pollen tube elongation, and transmission and development of the male gametophyte through analysis of the heterozygous GME/gme plants and the homozygous gme plants. Arabidopsis gme mutants also exhibit severe growth defects and early leaf senescence. Surprisingly, the defects in male gametophyte in the gme plants are not restored by L-ascorbate, boric acid or GDP-L-galactose, though boric acid rescues the growth defects of the mutants, indicating that GME may regulate male gametophyte development independent of L-ascorbate and GDP-L-galactose. These results reveal key roles for Arabidopsis GME in reproductive development, vegetative growth and leaf senescence, and suggest that GME regulates plant growth and controls male gametophyte development in different manners.

Synthesis and Physicochemical Characterization of D-Tagatose-1-phosphate: The Substrate of the Tagatose-1-Phosphate Kinase TagK in the PTS-mediated D-Tagatose Catabolic Pathway of Bacillus licheniformis

Science.gov (United States)

Van der Heiden, Edwige; Delmarcelle, Michaël; Simon, Patricia; Counson, Melody; Galleni, Moreno; Freedberg, Darón I.; Thompson, John; Joris, Bernard; Battistel, Marcos D.

2015-01-01

We report the first enzymatic synthesis of D-tagatose-1-phosphate (Tag-1P) by the multi-component PEP-dependent:tag-PTS present in tagatose-grown cells of Klebsiella pneumoniae. Physicochemical characterization by 31P and 1H NMR spectroscopy reveals that, in solution, this derivative is primarily in the pyranose form. Tag-1P was used to characterize the putative tagatose-1-phosphate kinase (TagK) of the Bacillus licheniformis PTS-mediated D-Tagatose catabolic Pathway (Bli-TagP). For this purpose, a soluble protein fusion was obtained with the 6 His-tagged trigger factor (TFHis6) of Escherichia coli. The active fusion enzyme was named TagK-TFHis6. Tag-1P and D-fructose-1-phosphate (Fru-1P) are substrates for the TagK-TFHis6 enzyme, whereas the isomeric derivatives D-tagatose-6-phosphate (Tag-6P) and D-fructose-6-phosphate (Fru-6P) are inhibitors. Studies of catalytic efficiency (kcat/Km) reveal that the enzyme specificity is markedly in favor of Tag-1P as substrate. Importantly, we show in vivo that the transfer of the phosphate moiety from PEP to the B. licheniformis tagatose-specific enzyme II (EIITag) in E.coli is inefficient. The capability of the PTS general cytoplasmic components of B. subtilis, HPr and EI, to restore the phosphate transfer is demonstrated. PMID:26159072

Synthesis and Physicochemical Characterization of D-Tagatose-1-Phosphate: The Substrate of the Tagatose-1-Phosphate Kinase in the Phosphotransferase System-Mediated D-Tagatose Catabolic Pathway of Bacillus licheniformis.

Science.gov (United States)

Van der Heiden, Edwige; Delmarcelle, Michaël; Simon, Patricia; Counson, Melody; Galleni, Moreno; Freedberg, Darón I; Thompson, John; Joris, Bernard; Battistel, Marcos D

2015-01-01

We report the first enzymatic synthesis of D-tagatose-1-phosphate (Tag-1P) by the multicomponent phosphoenolpyruvate:sugar phosphotransferase system (PEP-PTS) present in tagatose-grown cells of Klebsiella pneumoniae. Physicochemical characterization by (31)P and (1)H nuclear magnetic resonance spectroscopy reveals that, in solution, this derivative is primarily in the pyranose form. Tag-1P was used to characterize the putative tagatose-1-phosphate kinase (TagK) of the Bacillus licheniformis PTS-mediated D-tagatose catabolic pathway (Bli-TagP). For this purpose, a soluble protein fusion was obtained with the 6 His-tagged trigger factor (TF(His6)) of Escherichia coli. The active fusion enzyme was named TagK-TF(His6). Tag-1P and D-fructose-1-phosphate are substrates for the TagK-TF(His6) enzyme, whereas the isomeric derivatives D-tagatose-6-phosphate and D-fructose-6-phosphate are inhibitors. Studies of catalytic efficiency (kcat/Km) reveal that the enzyme specificity is markedly in favor of Tag-1P as the substrate. Importantly, we show in vivo that the transfer of the phosphate moiety from PEP to the B. licheniformis tagatose-specific Enzyme II in E. coli is inefficient. The capability of the PTS general cytoplasmic components of B. subtilis, HPr and Enzyme I to restore the phosphate transfer is demonstrated. © 2015 S. Karger AG, Basel.

Physicochemical and osteoplastic characteristics of 3D printed bone grafts based on synthetic calcium phosphates and natural polymers

Science.gov (United States)

Nezhurina, E. K.; Karalkin, P. A.; Komlev, V. S.; Sviridova, I. K.; Kirsanova, V. A.; Akhmedova, S. A.; Shanskiy, Ya D.; Fedotov, A. Yu; Barinov, S. M.; Sergeeva, N. S.

2018-04-01

A creation of personalized implants for regeneration of bone tissue seems to be a very promising biomedical technological approach. We have studied the physicochemical characteristics, cyto- and biocompatibility of three-dimensional constructs based on sodium alginate and gelatin in combination with 2 types of calcium phosphate (tricalcium phosphate or octacalcium phosphate) obtained by inkjet 3D printing. In our experiments, we have studied the physical and chemical properties of the constructs – their porosity, chemical composition, microarchitecture of the surface and mechanical elasticity. The cytocompatibility of 3D constructs and matrix-for-cell properties were investigated in vitro on a model of human osteosarcoma MG-63 cell line by means of MTT assay. The biocompatibility of 3D constructs was studied on the model of subcutaneous implantation in mice up to 12 weeks. All types of 3D constructs were cytocompatible in vitro, demonstrated good matrix-for-cells properties, and had supported cell proliferation for 2 weeks. In results of subcutaneous in vivo test all constructs demonstrated biocompatibility with slow bioresorption of organic and inorganic components. Osteogenesis proceeded more actively in rat tibia model defects (marginal excision), substituted by 3D printed 3-component implants based on alginate, gelatin and octacalcium phosphate.

Preliminary X-ray crystallographic analysis of the d-xylulose 5-phosphate phosphoketolase from Lactococcus lactis

International Nuclear Information System (INIS)

Petrareanu, Georgiana; Balasu, Mihaela C.; Zander, Ulrich; Scheidig, Axel J.; Szedlacsek, Stefan E.

2010-01-01

The expression, purification, preliminary crystallization and crystallographic analysis of phosphoketolase from L. lactis ssp. lactis (strain IL 1403) are reported. Phosphoketolases are thiamine diphosphate-dependent enzymes which play a central role in the pentose-phosphate pathway of heterofermentative lactic acid bacteria. They belong to the family of aldehyde-lyases and in the presence of phosphate ion cleave the carbon–carbon bond of the specific substrate d-xylulose 5-phosphate (or d-fructose 6-phosphate) to give acetyl phosphate and d-glyceraldehyde 3-phosphate (or d-erythrose 4-phosphate). Structural information about phosphoketolases is particularly important in order to fully understand their mechanism as well as the steric course of phosphoketolase-catalyzed reactions. Here, the purification, preliminary crystallization and crystallographic characterization of d-xylulose 5-phosphate phosphoketolase from Lactococcus lactis are reported. The presence of thiamine diphosphate during purification was essential for the enzymatic activity of the purified protein. The crystals belonged to the monoclinic space group P2 1 . Diffraction data were obtained to a resolution of 2.2 Å

Mechanistic studies of 3-deoxy-D-manno-octulosonic acid 8-phosphate synthase

International Nuclear Information System (INIS)

Dotson, G.D.; Woodard, R.W.

1994-01-01

The enzyme 3-deOXY-D-manno-octulosonic acid 8-phosphate synthase (KDO 8-P synthase) catalyses the condensation of arabinose 5-phosphate (A 5-P) with phosphoenolpyruvate (PEP) to give the unique eight-carbon acidic sugar 3-deoxy-D-nianno-octulosonic acid 8-phosphate (KDO 8-P) found only in gram-negative bacteria and required for lipid A maturation and cellular growth. The E. coli gene kdsA that encodes KDO 8-P synthase has been amplified by standard PCR methodologies. The synthetic gene, subcloned into the expression vector pT7-7 was used to infect E. coli BL 21 (DE 3). Purification of crude supernatant from this transformant on Q Sepharose yields >200 mg of near-homogeneous KDO 8-P synthase per liter of cell culture. To explore the mechanism of KDO 8-P synthase, we prepared (E)- and (Z)-(3 2 H)PEP, (2- 13 C)PEP, and (2- 13 C, 18 O)PEP chemically from the appropriately labeled 3-bromopyruvates by reaction with trimethylphosphite under Perkow reaction conditions. Our 1 H-NMR analysis of the stereochemistry at C3 of the KDO 8-Ps, obtained by separate incubation of (E)- and (Z)-(3- 2 H)PEP with A 5-P in the presence of KDO 8-P synthase, demonstrated that the reaction is stereospecific with respect to both the C3 of PEP and the C1 carbonyl of A 5-P. (Z)-(3- 2 H)PEP gave predominantly (3S)-(3 2 H)KDO 8-P and (E)-(3- 2 H)PEP gave predominantly (3R)-(3 2 H)KDO-8P, which indicates condensation of the si face of PEP upon the re face of A 5-P-an orientation analogous to that seen with the similar aldehyde Iyase DAH 7-P synthase. The fate of the enolic oxygen of (2- 13 C, 18 O)PEP, during the course of the KDO 8-P synthase-catalyzed reaction as monitored by both 13 C- and 31 P-NMR spectroscopy demonstrated that the inorganic phosphate (Pi) and not the KDO 8-P contained the 18 O

Mechanistic studies of 3-deoxy-D-manno-octulosonic acid 8-phosphate synthase

Energy Technology Data Exchange (ETDEWEB)

Dotson, G.D.; Woodard, R.W. [Univ. of Michigan, Ann Arbor, MI (United States)

1994-12-01

The enzyme 3-deOXY-D-manno-octulosonic acid 8-phosphate synthase (KDO 8-P synthase) catalyses the condensation of arabinose 5-phosphate (A 5-P) with phosphoenolpyruvate (PEP) to give the unique eight-carbon acidic sugar 3-deoxy-D-nianno-octulosonic acid 8-phosphate (KDO 8-P) found only in gram-negative bacteria and required for lipid A maturation and cellular growth. The E. coli gene kdsA that encodes KDO 8-P synthase has been amplified by standard PCR methodologies. The synthetic gene, subcloned into the expression vector pT7-7 was used to infect E. coli BL 21 (DE 3). Purification of crude supernatant from this transformant on Q Sepharose yields >200 mg of near-homogeneous KDO 8-P synthase per liter of cell culture. To explore the mechanism of KDO 8-P synthase, we prepared (E)- and (Z)-(3{sup 2}H)PEP, (2-{sup 13}C)PEP, and (2-{sup 13}C,{sup 18}O)PEP chemically from the appropriately labeled 3-bromopyruvates by reaction with trimethylphosphite under Perkow reaction conditions. Our {sup 1}H-NMR analysis of the stereochemistry at C3 of the KDO 8-Ps, obtained by separate incubation of (E)- and (Z)-(3-{sup 2}H)PEP with A 5-P in the presence of KDO 8-P synthase, demonstrated that the reaction is stereospecific with respect to both the C3 of PEP and the C1 carbonyl of A 5-P. (Z)-(3-{sup 2}H)PEP gave predominantly (3S)-(3{sup 2}H)KDO 8-P and (E)-(3-{sup 2}H)PEP gave predominantly (3R)-(3{sup 2}H)KDO-8P, which indicates condensation of the si face of PEP upon the re face of A 5-P-an orientation analogous to that seen with the similar aldehyde Iyase DAH 7-P synthase. The fate of the enolic oxygen of (2-{sup 13}C, {sup 18}O)PEP, during the course of the KDO 8-P synthase-catalyzed reaction as monitored by both {sup 13}C- and {sup 31}P-NMR spectroscopy demonstrated that the inorganic phosphate (Pi) and not the KDO 8-P contained the {sup 18}O.

Homology models guide discovery of diverse enzyme specificities among dipeptide epimerases in the enolase superfamily

Science.gov (United States)

Lukk, Tiit; Sakai, Ayano; Kalyanaraman, Chakrapani; Brown, Shoshana D.; Imker, Heidi J.; Song, Ling; Fedorov, Alexander A.; Fedorov, Elena V.; Toro, Rafael; Hillerich, Brandan; Seidel, Ronald; Patskovsky, Yury; Vetting, Matthew W.; Nair, Satish K.; Babbitt, Patricia C.; Almo, Steven C.; Gerlt, John A.; Jacobson, Matthew P.

2012-01-01

The rapid advance in genome sequencing presents substantial challenges for protein functional assignment, with half or more of new protein sequences inferred from these genomes having uncertain assignments. The assignment of enzyme function in functionally diverse superfamilies represents a particular challenge, which we address through a combination of computational predictions, enzymology, and structural biology. Here we describe the results of a focused investigation of a group of enzymes in the enolase superfamily that are involved in epimerizing dipeptides. The first members of this group to be functionally characterized were Ala-Glu epimerases in Eschericiha coli and Bacillus subtilis, based on the operon context and enzymological studies; these enzymes are presumed to be involved in peptidoglycan recycling. We have subsequently studied more than 65 related enzymes by computational methods, including homology modeling and metabolite docking, which suggested that many would have divergent specificities;, i.e., they are likely to have different (unknown) biological roles. In addition to the Ala-Phe epimerase specificity reported previously, we describe the prediction and experimental verification of: (i) a new group of presumed Ala-Glu epimerases; (ii) several enzymes with specificity for hydrophobic dipeptides, including one from Cytophaga hutchinsonii that epimerizes D-Ala-D-Ala; and (iii) a small group of enzymes that epimerize cationic dipeptides. Crystal structures for certain of these enzymes further elucidate the structural basis of the specificities. The results highlight the potential of computational methods to guide experimental characterization of enzymes in an automated, large-scale fashion. PMID:22392983

3D WO3 /BiVO4 /Cobalt Phosphate Composites Inverse Opal Photoanode for Efficient Photoelectrochemical Water Splitting.

Science.gov (United States)

Zhang, Haifeng; Zhou, Weiwei; Yang, Yaping; Cheng, Chuanwei

2017-04-01

A novel 3D WO 3 /BiVO 4 /cobalt phosphate composite inverse opal is designed for photoeletrochemical (PEC) water splitting, yielding a significantly improved PEC performance. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Radical-induced dephosphorylation of fructose phosphates in aqueous solution

International Nuclear Information System (INIS)

Zegota, H.; Sonntag, C. von

1981-01-01

Oxygen free N 2 O-saturated aqueous solutions of D-fructose-1-phosphate and D-fructose-6-phosphate were γ-irradiated. Inorganic phosphate and phosphate free sugars (containing four to six carbon atoms) were identified and their G-values measured. D-Fructose-1-phosphate yields (G-values in parentheses) inorganic phosphate (1.6), hexos-2-ulose (0.12), 6-deoxy-2,5-hexodiulose (0.16), tetrulose (0.05) and 3-deoxytetrulose (0.15). D-Fructose-6-phosphate yields inorganic phosphate (1.7), hexos-5-ulose (0.1), 6-deoxy-2,5-hexodiulose (0.36), 3-deoxy-2,5-hexodiulose and 2-deoxyhexos-5-ulose (together 0.18). On treatment with alkaline phosphatase further deoxy sugars were recognized and in fructose-1-phosphate G(6-deoxy-2,5-hexodiulose) was increased to a G-value of 0.4. Dephosphorylation is considered to occur mainly after OH attack at C-5 and C-1 in fructose-1-phosphate and at C-5 and C-6 in fructose-6-phosphate. Reaction mechanisms are discussed. (orig.)

ORF Alignment: NC_000117 [GENIUS II[Archive

Lifescience Database Archive (English)

Full Text Available sphate 3-epimerase (Pentose-5-phosphate ... 3-epimerase) (PPE) (R5P3E) ... Length = 216 ... Query: 1 ... MREEAMKKQGVLVAPSIM...GADLACIGREARNIEESGADLIHIDVMDGHFVPNITFGPGVV 60 ... MREEAMKKQGVLVAPSIMGADLACIGR...EARNIEESGADLIHIDVMDGHFVPNITFGPGVV Sbjct: 1 ... MREEAMKKQGVLVAPSIMGADLACIGREARNIEESG

ORF Alignment: NC_002620 [GENIUS II[Archive

Lifescience Database Archive (English)

Full Text Available hosphate 3-epimerase (Pentose-5-phosphate ... 3-epimerase) (PPE) (R5P3E) ... Length = 205 ... Query: 7 ... LIAPSIM...GADLACLGDAARNIEESGANLIHIDVMDGHFVPNITFGPGIIAAINRSTDLFL 66 ... LIAPSIMGADLACLGDAARNIEESG...ANLIHIDVMDGHFVPNITFGPGIIAAINRSTDLFL Sbjct: 1 ... LIAPSIMGADLACLGDAARNIEESGANLIHIDVM

Glucose and fructose 6-phosphate cycle in humans

International Nuclear Information System (INIS)

Karlander, S.; Roovete, A.; Vranic, M.; Efendic, S.

1986-01-01

We have determined the rate of glucose cycling by comparing turnovers of [2- 3 H]- and [6- 3 H]glucose under basal conditions and during a glucose infusion. Moreover, the activity of the fructose 6-phosphate cycle was assessed by comparing [3- 3 H]- and [6- 3 H]glucose. The study included eight lean subjects with normal glucose tolerance. They participated in two randomly performed investigations. In one experiment [2- 3 H]- and [6- 3 H]glucose were given simultaneously, while in the other only [3- 3 H]glucose was given. The basal rate of glucose cycling was 0.32 +/- 0.08 mg X kg-1 X min-1 or 17% of basal glucose production (P less than 0.005). During glucose infusion the activity of endogenous glucose cycling did not change but since glucose production was suppressed it amounted to 130% of glucose production. The basal fructose 6-phosphate cycle could be detected only in three subjects and was suppressed during glucose infusion. In conclusion, the glucose cycle is active in healthy humans both in basal conditions and during moderate hyperglycemia. In some subjects, the fructose 6-phosphate cycle also appears to be active. Thus it is preferable to use [6- 3 H]glucose rather than [3- 3 H]glucose when measuring glucose production and particularly when assessing glucose cycle

Time course of radiolabeled 2-deoxy-D-glucose 6-phosphate turnover in cerebral cortex of goats

International Nuclear Information System (INIS)

Pelligrino, D.A.; Miletich, D.J.; Albrecht, R.F.

1987-01-01

The vivo dephosphorylation rate of 2-deoxy-D-glucose 6-phosphate (DGP) in the cerebral cortex of goats injected intravenously with radiolabeled 2-deoxy-D-glucose (DG) was investigated. Serial rapidly frozen samples of parietal cortical gray tissue were obtained at regular intervals over time periods from 45 min to 3 h in awake goats or in paralyzed and artificially ventilated goats maintained under 70% N 2 O or pentobarbital sodium anesthesia. The samples were analyzed for glucose content and separate DG and DGP activities. The rate parameters for phosphorylation (k/sup */ 4 ) and dephosphorylation (k/sup */ 4 ) were estimated in each animal. The glucose phosphorylation rate (PR) was calculated over the intervals 3-5 (or 6), 3-10, 3-20, 3-30, and 3-45 min, assuming k/sup */ 4 = O. As the evaluation period was extended beyond 10 min, the calculated PR became increasingly less when compared with that calculated over the 3- to 5- (or 6) min interval (PR/sub i/). Furthermore, as metabolic activity decreased, the magnitude of the error increased such that at 45 min pentobarbital-anesthetize goats underestimated the PR/sub i/ by 46.5% compared with only 23.1 in N 2 O-anesthetized goats. This was also reflected in the >twofold higher k/sup */ 4 /k/sup */ 3 ratio in the pentobarbital vs. N 2 O-anesthetized group. It is concluded that when using the DG method in the goat, DGP dephosphorylation cannot be ignored when employing >10-min evaluation periods

Structures of Staphylococcus aureus D-tagatose-6-phosphate kinase implicate domain motions in specificity and mechanism.

Science.gov (United States)

Miallau, Linda; Hunter, William N; McSweeney, Sean M; Leonard, Gordon A

2007-07-06

High resolution structures of Staphylococcus aureus d-tagatose-6-phosphate kinase (LacC) in two crystal forms are herein reported. The structures define LacC in apoform, in binary complexes with ADP or the co-factor analogue AMP-PNP, and in a ternary complex with AMP-PNP and D-tagatose-6-phosphate. The tertiary structure of the LacC monomer, which is closely related to other members of the pfkB subfamily of carbohydrate kinases, is composed of a large alpha/beta core domain and a smaller, largely beta "lid." Four extended polypeptide segments connect these two domains. Dimerization of LacC occurs via interactions between lid domains, which come together to form a beta-clasp structure. Residues from both subunits contribute to substrate binding. LacC adopts a closed structure required for phosphoryl transfer only when both substrate and co-factor are bound. A reaction mechanism similar to that used by other phosphoryl transferases is proposed, although unusually, when both substrate and co-factor are bound to the enzyme two Mg(2+) ions are observed in the active site. A new motif of amino acid sequence conservation common to the pfkB subfamily of carbohydrate kinases is identified.

Cloning, expression, purification, crystallization and preliminary X-ray crystallographic analysis of the mannose 6-phosphate isomerase from Salmonella typhimurium

Energy Technology Data Exchange (ETDEWEB)

Gowda, Giri; Sagurthi, Someswar Rao [Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012 (India); Savithri, H. S. [Department of Biochemistry, Indian Institute of Science, Bangalore 560 012 (India); Murthy, M. R. N., E-mail: mrn@mbu.iisc.ernet.in [Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012 (India)

2008-02-01

The cloning, expression, purification, crystallization and preliminary X-ray crystallographic studies of mannose 6-phosphate isomerase from S. typhimurium are reported. Mannose 6-phosphate isomerase (MPI; EC 5.3.1.8) catalyzes the reversible isomerization of d-mannose 6-phosphate (M6P) and d-fructose 6-phosphate (F6P). In the eukaryotes and prokaryotes investigated to date, the enzyme has been reported to play a crucial role in d-mannose metabolism and supply of the activated mannose donor guanosine diphosphate d-mannose (GDP-d-mannose). In the present study, MPI was cloned from Salmonella typhimurium, overexpressed in Escherichia coli and purified using Ni–NTA affinity column chromatography. Purified MPI crystallized in space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 36.03, b = 92.2, c = 111.01 Å. A data set extending to 1.66 Å resolution was collected with 98.8% completeness using an image-plate detector system mounted on a rotating-anode X-ray generator. The asymmetric unit of the crystal cell was compatible with the presence of a monomer of MPI. A preliminary structure solution of the enzyme has been obtained by molecular replacement using Candida albicans MPI as the phasing model and the program Phaser. Further refinement and model building are in progress.

Erythrocyte glucose-6-phosphate dehydrogenase from Brazilian opossum Didelphis marsupialis

Directory of Open Access Journals (Sweden)

Barretto O.C. de O.

2006-01-01

Full Text Available In a comparative study of erythrocyte metabolism of vertebrates, the specific activity of glucose-6-phosphate dehydrogenase (G6PD of the Brazilian opossum Didelphis marsupialis in a hemolysate was shown to be high, 207 ± 38 IU g-1 Hb-1 min-1 at 37ºC, compared to the human erythrocyte activity of 12 ± 2 IU g-1 Hb-1 min-1 at 37ºC. The apparent high specific activity of the mixture led us to investigate the physicochemical properties of the opossum enzyme. We report that reduced glutathione (GSH in the erythrocytes was only 50% higher than in human erythrocytes, a value lower than expected from the high G6PD activity since GSH is maintained in a reduced state by G6PD activity. The molecular mass, determined by G-200 Sephadex column chromatography at pH 8.0, was 265 kDa, which is essentially the same as that of human G6PD (260 kDa. The Michaelis-Menten constants (Km: 55 µM for glucose-6-phosphate and nicotinamide adenine dinucleotide phosphate (Km: 3.3 µM were similar to those of the human enzyme (Km: 50-70 and Km: 2.9-4.4, respectively. A 450-fold purification of the opossum enzyme was achieved and the specific activity of the purified enzyme, 90 IU/mg protein, was actually lower than the 150 IU/mg protein observed for human G6PD. We conclude that G6PD after purification from the hemolysate of D. marsupialis does not have a high specific activity. Thus, it is quite probable that the red cell hyperactivity reported may be explained by increased synthesis of G6PD molecules per unit of hemoglobin or to reduced inactivation in the RBC hemolysate.

Low temperature fabrication of magnesium phosphate cement scaffolds by 3D powder printing.

Science.gov (United States)

Klammert, Uwe; Vorndran, Elke; Reuther, Tobias; Müller, Frank A; Zorn, Katharina; Gbureck, Uwe

2010-11-01

Synthetic bone replacement materials are of great interest because they offer certain advantages compared with organic bone grafts. Biodegradability and preoperative manufacturing of patient specific implants are further desirable features in various clinical situations. Both can be realised by 3D powder printing. In this study, we introduce powder-printed magnesium ammonium phosphate (struvite) structures, accompanied by a neutral setting reaction by printing farringtonite (Mg(3)(PO(4))(2)) powder with ammonium phosphate solution as binder. Suitable powders were obtained after sintering at 1100°C for 5 h following 20-40 min dry grinding in a ball mill. Depending on the post-treatment of the samples, compressive strengths were found to be in the range 2-7 MPa. Cytocompatibility was demonstrated in vitro using the human osteoblastic cell line MG63.

Molecular And 3D-Structural Characterization Of Fructose-1,6-Bisphosphate Aldolase Derived From Metroxylon Sagu

Directory of Open Access Journals (Sweden)

Hairul Azman Roslan

2017-06-01

Full Text Available ABSTRACT Fructose-1,6-bisphosphate aldolase (FBAld is an enzyme that catalyzes the cleavage of D-fructose-1,6-phosphate (FBP to D-glyceraldehyde-3-phosphate (G3P and dihydroxyacetone phosphate (DHAP, and plays vital role in glycolysis and gluconeogenesis. However, molecular characterization and functional roles of FBAld remain unknown in sago palm. Here we report a modified CTAB-RNA extraction method was developed for the isolation of good quality RNA (RIN>8 from sago leaves and the isolation of FBAld cDNA from sago palm. The isolated sago FBAld (msFBAld cDNA has total length of 1288 bp with an open reading frame of 1020 bp and a predicted to encode for a protein of 340 amino acid resides. The predicted protein shared a high degree of homology with Class-I FBAld from other plants. Meanwhile, the msFBAld gene spanned 2322 bp and consisted of five exons. Conserved domain search identified fifteen catalytically important amino acids at the active site and phylogenetic tree revealed localization of msFBAld in the chloroplast. A molecular 3D-structure of msFBAld was generated by homology modeling and a Ramachandran plot with 86.7% of the residues in the core region, 13.4% in the allowed region with no residues in the disallowed region. The modeled structure is a homotetramer containing an (/(-TIM-barrel at the center. Superimposition of the model with Class-I aldolases identified a catalytic dyad, Lys209-Glu167, which could be involved in the Schiff's base formation and aldol condensation. Apart from that, overproduction of the recombinant msFBAld in Escherichia coli resulted in increased tolerance towards salinity.

Cloning and Expression of Three New Azotobacter vinelandii Genes Closely Related to a Previously Described Gene Family Encoding Mannuronan C-5-Epimerases

OpenAIRE

Svanem, Britt Iren Glærum; Skjåk-Bræk, Gudmund; Ertesvåg, Helga; Valla, Svein

1999-01-01

The cloning and expression of a family of five modular-type mannuronan C-5-epimerase genes from Azotobacter vinelandii (algE1 to -5) has previously been reported. The corresponding proteins catalyze the Ca2+-dependent polymer-level epimerization of β-d-mannuronic acid to α-l-guluronic acid (G) in the commercially important polysaccharide alginate. Here we report the identification of three additional structurally similar genes, designated algE6, algE7, and algY. All three genes were sequenced...

Design and production of sintered β-tricalcium phosphate 3D scaffolds for bone tissue regeneration

International Nuclear Information System (INIS)

Santos, Carlos F.L.; Silva, Abílio P.; Lopes, Luís; Pires, Inês; Correia, Ilidio J.

2012-01-01

The characteristics of sintered β-tricalcium phosphate (β-TCP) scaffolds produced by 3D printing were studied by means of X-ray diffraction, Scanning Electron Microscopy, Fourier transform infrared spectroscopy, uniaxial compression tests and cytotoxicity tests, using human osteoblast cells. The results reported include details of the β-TCP scaffolds' porosity, density, phase stability, mechanical behavior and cytotoxic profile. Collectively, these properties are fundamental for the future application of these scaffolds as bone substitutes for individualized therapy. Highlights: ► β-Tricalcium phosphate (β-TCP) 3D scaffolds were produced by rapid prototyping. ► Scaffold properties were assessed by SEM, FTIR, XRD and by mechanical tests. ► The cytotoxic profile of the scaffolds was characterized by in vitro assays. ► Scaffolds have good properties for its application as bone substitutes for individualized therapy.

Trehalose 6-phosphate phosphatases of Pseudomonas aeruginosa.

Science.gov (United States)

Cross, Megan; Biberacher, Sonja; Park, Suk-Youl; Rajan, Siji; Korhonen, Pasi; Gasser, Robin B; Kim, Jeong-Sun; Coster, Mark J; Hofmann, Andreas

2018-04-24

The opportunistic bacterium Pseudomonas aeruginosa has been recognized as an important pathogen of clinical relevance and is a leading cause of hospital-acquired infections. The presence of a glycolytic enzyme in Pseudomonas, which is known to be inhibited by trehalose 6-phosphate (T6P) in other organisms, suggests that these bacteria may be vulnerable to the detrimental effects of intracellular T6P accumulation. In the present study, we explored the structural and functional properties of trehalose 6-phosphate phosphatase (TPP) in P. aeruginosa in support of future target-based drug discovery. A survey of genomes revealed the existence of 2 TPP genes with either chromosomal or extrachromosomal location. Both TPPs were produced as recombinant proteins, and characterization of their enzymatic properties confirmed specific, magnesium-dependent catalytic hydrolysis of T6P. The 3-dimensional crystal structure of the chromosomal TPP revealed a protein dimer arising through β-sheet expansion of the individual monomers, which possess the overall fold of halo-acid dehydrogenases.-Cross, M., Biberacher, S., Park, S.-Y., Rajan, S., Korhonen, P., Gasser, R. B., Kim, J.-S., Coster, M. J., Hofmann, A. Trehalose 6-phosphate phosphatases of Pseudomonas aeruginosa.

Hydrogels based on polysaccharide-calcium phosphate with antibacterial / antitumor activity for 3D printing

Science.gov (United States)

Teterina, A. Yu; Fedotov, A. Yu; Zobkov, Yu V.; Sergeeva, N. S.; Sviridova, I. K.; Kirsanova, V. A.; Karalkin, P. A.; Komlev, V. S.

2018-04-01

The purpose of this study was to develop hydrogels for 3D printing of sodium alginate/gelatin/octacalcium phosphate-based constructs with antibacterial and antitumor activity intended for bone defects replacement in patients with malignant diseases. In this work, we evaluated the drug release kinetic and physico-chemical characteristics of constructs, as well as their specific activity, biocompatibility and osteoplastic properties by means of in vitro and in vivo tests. The principal possibility of creating the biocompatible bone substitutes with antibacterial/antitumor activity and osteoconductive-retaining properties of 3D printing method was demonstrated.

Design and production of sintered {beta}-tricalcium phosphate 3D scaffolds for bone tissue regeneration

Energy Technology Data Exchange (ETDEWEB)

Santos, Carlos F.L. [CICS-UBI - Centro de Investigacao em Ciencias da Saude, Universidade da Beira Interior, Covilha (Portugal); Silva, Abilio P. [Centro de Ciencia e Tecnologia Aeroespaciais, Universidade da Beira Interior, Covilha (Portugal); Lopes, Luis [CICS-UBI - Centro de Investigacao em Ciencias da Saude, Universidade da Beira Interior, Covilha (Portugal); Pires, Ines [Instituto de Engenharia Mecanica - Lisboa (IDMEC Lisboa/IST/UTL), Avenida Rovisco Pais, 1049-001 Lisboa (Portugal); Correia, Ilidio J., E-mail: icorreia@ubi.pt [CICS-UBI - Centro de Investigacao em Ciencias da Saude, Universidade da Beira Interior, Covilha (Portugal)

2012-07-01

The characteristics of sintered {beta}-tricalcium phosphate ({beta}-TCP) scaffolds produced by 3D printing were studied by means of X-ray diffraction, Scanning Electron Microscopy, Fourier transform infrared spectroscopy, uniaxial compression tests and cytotoxicity tests, using human osteoblast cells. The results reported include details of the {beta}-TCP scaffolds' porosity, density, phase stability, mechanical behavior and cytotoxic profile. Collectively, these properties are fundamental for the future application of these scaffolds as bone substitutes for individualized therapy. Highlights: Black-Right-Pointing-Pointer {beta}-Tricalcium phosphate ({beta}-TCP) 3D scaffolds were produced by rapid prototyping. Black-Right-Pointing-Pointer Scaffold properties were assessed by SEM, FTIR, XRD and by mechanical tests. Black-Right-Pointing-Pointer The cytotoxic profile of the scaffolds was characterized by in vitro assays. Black-Right-Pointing-Pointer Scaffolds have good properties for its application as bone substitutes for individualized therapy.

Heparan sulfate C5-epimerase is essential for heparin biosynthesis in mast cells.

Science.gov (United States)

Feyerabend, Thorsten B; Li, Jin-Ping; Lindahl, Ulf; Rodewald, Hans-Reimer

2006-04-01

Biosynthesis of heparin, a mast cell-derived glycosaminoglycan with widespread importance in medicine, has not been fully elucidated. In biosynthesis of heparan sulfate (HS), a structurally related polysaccharide, HS glucuronyl C5-epimerase (Hsepi) converts D-glucuronic acid (GlcA) to L-iduronic acid (IdoA) residues. We have generated Hsepi-null mouse mutant mast cells, and we show that the same enzyme catalyzes the generation of IdoA in heparin and that 'heparin' lacking IdoA shows a distorted O-sulfation pattern.

Equilibriums of sorption of impurities of 3 d - cations by inorganic sorbents from phosphate and arsenate solutions

International Nuclear Information System (INIS)

Filatova, L.N.; Kurdyumova, T.N.; Bagrov, V.M.; Blyum, G.Z.

1986-01-01

Present article is devoted to equilibriums of sorption of impurities of 3 d - cations by inorganic sorbents from phosphate and arsenate solutions. Equilibriums of sorption of microquantities of iron, scandium, zink, copper, cobalt and manganese by inorganic sorbents on the basis of titanium and aluminium oxides from phosphate and arsenate solutions are studied. The influence of structural and chemical properties of matrix on sorption properties of oxides in phosphate and arsenate solutions is studied as well. It is defined that in concentrated solutions the sorption value of trace contaminant depends on a character of cation of alkaline metal.

3D surface topography study of the biofunctionalized nanocrystalline Ti–6Zr–4Nb/Ca–P

International Nuclear Information System (INIS)

Jakubowicz, J.; Adamek, G.; Jurczyk, M.U.; Jurczyk, M.

2012-01-01

In this work surface of the sintered Ti–6Zr–4Nb nanocrystalline alloy was electrochemically biofunctionalized. The porous surface was produced by anodic oxidation in 1 M H 3 PO 4 + 2%HF electrolyte at 10 V for 30 min. Next the calcium–phosphate (Ca–P) layer was deposited, onto the formed porous surface, using cathodic potential − 5 V kept for 60 min in 0.042 M Ca(NO 3 ) 2 + 0.025 M (NH 4 ) 2 HPO 4 + 0.1 M HCl electrolyte. The deposited Ca–P layer anchored in the pores. The biofunctionalized surface was studied by XRD, SEM and EDS. In vitro tests culture of normal human osteoblast (NHOst) cells showed very good cells proliferation, colonization and multilayering. Using optical profiler, roughness and hybrid 3D surface topography parameters were estimated. Correlation between surface composition, morphology, roughness and biocompatibility results was done. It has been shown by us that surface with appropriate chemical composition and topography, after combined electrochemical anodic and cathodic surface treatment, supports osteoblast adhesion and proliferation. 3D topography measurements using optical profiler play a key role in the biomaterials surface analysis. - Highlights: ► Nanocrystalline Ti–6Zr–4Nb/Ca–P material was produced for hard tissue implant applications. ► Calcium-phosphate results in surface biofunctionalization. ► The biofunctionalized surface shows good in-vitro behavior.

Effects of 3D-Printed Polycaprolactone/?-Tricalcium Phosphate Membranes on Guided Bone Regeneration

OpenAIRE

Shim, Jin-Hyung; Won, Joo-Yun; Park, Jung-Hyung; Bae, Ji-Hyeon; Ahn, Geunseon; Kim, Chang-Hwan; Lim, Dong-Hyuk; Cho, Dong-Woo; Yun, Won-Soo; Bae, Eun-Bin; Jeong, Chang-Mo; Huh, Jung-Bo

2017-01-01

This study was conducted to compare 3D-printed polycaprolactone (PCL) and polycaprolactone/β-tricalcium phosphate (PCL/β-TCP) membranes with a conventional commercial collagen membrane in terms of their abilities to facilitate guided bone regeneration (GBR). Fabricated membranes were tested for dry and wet mechanical properties. Fibroblasts and preosteoblasts were seeded into the membranes and rates and patterns of proliferation were analyzed using a kit-8 assay and by scanning electron micro...

Metabolic engineering of the pentose phosphate pathway for enhanced limonene production in the cyanobacterium Synechocysti s sp. PCC 6803.

Science.gov (United States)

Lin, Po-Cheng; Saha, Rajib; Zhang, Fuzhong; Pakrasi, Himadri B

2017-12-13

Isoprenoids are diverse natural compounds, which have various applications as pharmaceuticals, fragrances, and solvents. The low yield of isoprenoids in plants makes them difficult for cost-effective production, and chemical synthesis of complex isoprenoids is impractical. Microbial production of isoprenoids has been considered as a promising approach to increase the yield. In this study, we engineered the model cyanobacterium Synechocystis sp. PCC 6803 for sustainable production of a commercially valuable isoprenoid, limonene. Limonene synthases from the plants Mentha spicata and Citrus limon were expressed in cyanobacteria for limonene production. Production of limonene was two-fold higher with limonene synthase from M. spicata than that from C. limon. To enhance isoprenoid production, computational strain design was conducted by applying the OptForce strain design algorithm on Synechocystis 6803. Based on the metabolic interventions suggested by this algorithm, genes (ribose 5-phosphate isomerase and ribulose 5-phosphate 3-epimerase) in the pentose phosphate pathway were overexpressed, and a geranyl diphosphate synthase from the plant Abies grandis was expressed to optimize the limonene biosynthetic pathway. The optimized strain produced 6.7 mg/L of limonene, a 2.3-fold improvement in productivity. Thus, this study presents a feasible strategy to engineer cyanobacteria for photosynthetic production of isoprenoids.

Elucidation of substrate specificity in Aspergillus nidulans UDP-galactose-4-epimerase.

Directory of Open Access Journals (Sweden)

Sean A Dalrymple

Full Text Available The frequency of invasive fungal infections has rapidly increased in recent years. Current clinical treatments are experiencing decreased potency due to severe host toxicity and the emergence of fungal drug resistance. As such, new targets and their corresponding synthetic pathways need to be explored for drug development purposes. In this context, galactofuranose residues, which are employed in fungal cell wall construction, but are notably absent in animals, represent an appealing target. Herein we present the structural and biochemical characterization of UDP-galactose-4-epimerase from Aspergillus nidulans which produces the precursor UDP-galactopyranose required for galactofuranose synthesis. Examination of the structural model revealed both NAD(+ and UDP-glucopyranose were bound within the active site cleft in a near identical fashion to that found in the Human epimerase. Mutational studies on the conserved catalytic motif support a similar mechanism to that established for the Human counterpart is likely operational within the A. nidulans epimerase. While the K m and k cat for the enzyme were determined to be 0.11 mM and 12.8 s(-1, respectively, a single point mutation, namely L320C, activated the enzyme towards larger N-acetylated substrates. Docking studies designed to probe active site affinity corroborate the experimentally determined activity profiles and support the kinetic inhibition results.

Genetics Home Reference: glucose-6-phosphate dehydrogenase deficiency

Science.gov (United States)

... deficiency Encyclopedia: Glucose-6-phosphate dehydrogenase test Encyclopedia: Hemolytic anemia Encyclopedia: Newborn jaundice Health Topic: Anemia Health Topic: G6PD Deficiency Health Topic: Newborn Screening Genetic and Rare Diseases Information Center (1 link) Glucose-6-phosphate dehydrogenase ...

3D printing of mineral-polymer bone substitutes based on sodium alginate and calcium phosphate.

Science.gov (United States)

Egorov, Aleksey A; Fedotov, Alexander Yu; Mironov, Anton V; Komlev, Vladimir S; Popov, Vladimir K; Zobkov, Yury V

2016-01-01

We demonstrate a relatively simple route for three-dimensional (3D) printing of complex-shaped biocompatible structures based on sodium alginate and calcium phosphate (CP) for bone tissue engineering. The fabrication of 3D composite structures was performed through the synthesis of inorganic particles within a biopolymer macromolecular network during 3D printing process. The formation of a new CP phase was studied through X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy. Both the phase composition and the diameter of the CP particles depend on the concentration of a liquid component (i.e., the "ink"). The 3D printed structures were fabricated and found to have large interconnected porous systems (mean diameter ≈800 μm) and were found to possess compressive strengths from 0.45 to 1.0 MPa. This new approach can be effectively applied for fabrication of biocompatible scaffolds for bone tissue engineering constructions.

3D Powder Printed Bioglass and β-Tricalcium Phosphate Bone Scaffolds

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Michael Seidenstuecker

2017-12-01

Full Text Available The use of both bioglass (BG and β tricalcium phosphate (β-TCP for bone replacement applications has been studied extensively due to the materials’ high biocompatibility and ability to resorb when implanted in the body. 3D printing has been explored as a fast and versatile technique for the fabrication of porous bone scaffolds. This project investigates the effects of using different combinations of a composite BG and β-TCP powder for 3D printing of porous bone scaffolds. Porous 3D powder printed bone scaffolds of BG, β-TCP, 50/50 BG/β-TCP and 70/30 BG/β-TCP compositions were subject to a variety of characterization and biocompatibility tests. The porosity characteristics, surface roughness, mechanical strength, viability for cell proliferation, material cytotoxicity and in vitro bioactivity were assessed. The results show that the scaffolds can support osteoblast-like MG-63 cells growth both on the surface of and within the scaffold material and do not show alarming cytotoxicity; the porosity and surface characteristics of the scaffolds are appropriate. Of the two tested composite materials, the 70/30 BG/β-TCP scaffold proved to be superior in terms of biocompatibility and mechanical strength. The mechanical strength of the scaffolds makes them unsuitable for load bearing applications. However, they can be useful for other applications such as bone fillers.

3D printing of mineral–polymer bone substitutes based on sodium alginate and calcium phosphate

Directory of Open Access Journals (Sweden)

Aleksey A. Egorov

2016-11-01

Full Text Available We demonstrate a relatively simple route for three-dimensional (3D printing of complex-shaped biocompatible structures based on sodium alginate and calcium phosphate (CP for bone tissue engineering. The fabrication of 3D composite structures was performed through the synthesis of inorganic particles within a biopolymer macromolecular network during 3D printing process. The formation of a new CP phase was studied through X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy. Both the phase composition and the diameter of the CP particles depend on the concentration of a liquid component (i.e., the “ink”. The 3D printed structures were fabricated and found to have large interconnected porous systems (mean diameter ≈800 μm and were found to possess compressive strengths from 0.45 to 1.0 MPa. This new approach can be effectively applied for fabrication of biocompatible scaffolds for bone tissue engineering constructions.

Dinuclear copper(II) complexes with {Cu2(mu-hydroxo)bis(mu-carboxylato)}+ cores and their reactions with sugar phosphate esters: A substrate binding model of fructose-1,6-bisphosphatase.

Science.gov (United States)

Kato, Merii; Tanase, Tomoaki; Mikuriya, Masahiro

2006-04-03

Reactions of CuX2.nH2O with the biscarboxylate ligand XDK (H2XDK = m-xylenediamine bis(Kemp's triacid imide)) in the presence of N-donor auxiliary ligands yielded a series of dicopper(II) complexes, [Cu2(mu-OH)(XDK)(L)2]X (L = N,N,N',N'-tetramethylethylenediamine (tetmen), X = NO3 (1a), Cl (1b); L = N,N,N'-trimethylethylenediamine (tmen), X = NO3 (2a), Cl (2b); L =2,2'-bipyridine (bpy), X = NO3 (3); L = 1,10-phenanthroline (phen), X = NO3 (4); L = 4,4'-dimethyl-2,2'-bipyridine (Me2bpy), X = NO3 (5); L = 4-methyl-1,10-phenanthroline (Mephen), X = NO3 (6)). Complexes 1-6 were characterized by X-ray crystallography (Cu...Cu = 3.1624(6)-3.2910(4) A), and the electrochemical and magnetic properties were also examined. Complexes 3 and 4 readily reacted with diphenyl phosphoric acid (HDPP) or bis(4-nitrophenyl) phosphoric acid (HBNPP) to give [Cu2(mu-phosphate)(XDK)(L)2]NO3 (L = bpy, phosphate = DPP (11); L = phen, phosphate = DPP (12), BNPP (13)), where the phsophate diester bridges the two copper ions in a mu-1,3-O,O' bidentate fashion (Cu...Cu = 4.268(3)-4.315(1) A). Complexes 4 and 6 with phen and Mephen have proven to be good precursors to accommodate a series of sugar monophosphate esters (Sugar-P) onto the biscarboxylate-bridged dicopper centers, yielding [Cu2(mu-Sugar-P)(XDK)(L)2] (Sugar-P = alpha-D-Glc-1-P (23a and b), D-Glc-6-P (24a and b), D-Man-6-P (25a), D-Fru-6-P (26a and b); L = phen (a), Mephen (b)) and [Cu2(mu-Gly-n-P)(XDK)(Mephen)2] (Gly-n-P = glycerol n-phosphate; n = 2 (21), 3 (22)), where Glc, Man, and Fru are glucose, mannose, and fructose, respectively. The structure of [Cu2(mu-MNPP)(XDK)(phen)2(CH3OH)] (20) was characterized as a reference compound (H2MNPP = 4-nitrophenyl phosphoric acid). Complexes 4 and 6 also reacted with d-fructose 1,6-bisphosphate (D-Fru-1,6-P2) to afford the tetranuclear copper(II) complexes formulated as [Cu4(mu-D-Fru-1,6-P2)(XDK)2(L)4] (L = phen (27a), Mephen (27b)). The detailed structure of 27a was determined by X

Structural and mutational characterization of the catalytic A-module of the mannuronan C-5-epimerase AlgE4 from Azotobacter vinelandii

NARCIS (Netherlands)

Rozeboom, Henriette J.; Bjerkan, Tonje M.; Kalk, Kor H.; Ertesvag, Helga; Holtan, Synnove; Aachmann, Finn L.; Valla, Svein; Dijkstra, Bauke W.; Ertesvåg, Helga; Holtan, Synnøve

2008-01-01

Alginate is a family of linear copolymers of (1 -> 4)-linked beta-D-mannuronic acid and its C-5 epimer alpha-L-guluronic acid. The polymer is first produced as polymannuronic acid and the guluronic acid residues are then introduced at the polymer level by mannuronan C-5-epimerases. The structure of

Effects of 3D-Printed Polycaprolactone/β-Tricalcium Phosphate Membranes on Guided Bone Regeneration.

Science.gov (United States)

Shim, Jin-Hyung; Won, Joo-Yun; Park, Jung-Hyung; Bae, Ji-Hyeon; Ahn, Geunseon; Kim, Chang-Hwan; Lim, Dong-Hyuk; Cho, Dong-Woo; Yun, Won-Soo; Bae, Eun-Bin; Jeong, Chang-Mo; Huh, Jung-Bo

2017-04-25

This study was conducted to compare 3D-printed polycaprolactone (PCL) and polycaprolactone/β-tricalcium phosphate (PCL/β-TCP) membranes with a conventional commercial collagen membrane in terms of their abilities to facilitate guided bone regeneration (GBR). Fabricated membranes were tested for dry and wet mechanical properties. Fibroblasts and preosteoblasts were seeded into the membranes and rates and patterns of proliferation were analyzed using a kit-8 assay and by scanning electron microscopy. Osteogenic differentiation was verified by alizarin red S and alkaline phosphatase (ALP) staining. An in vivo experiment was performed using an alveolar bone defect beagle model, in which defects in three dogs were covered with different membranes. CT and histological analyses at eight weeks after surgery revealed that 3D-printed PCL/β-TCP membranes were more effective than 3D-printed PCL, and substantially better than conventional collagen membranes in terms of biocompatibility and bone regeneration and, thus, at facilitating GBR.

Effects of 3D-Printed Polycaprolactone/β-Tricalcium Phosphate Membranes on Guided Bone Regeneration

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Jin-Hyung Shim

2017-04-01

Full Text Available This study was conducted to compare 3D-printed polycaprolactone (PCL and polycaprolactone/β-tricalcium phosphate (PCL/β-TCP membranes with a conventional commercial collagen membrane in terms of their abilities to facilitate guided bone regeneration (GBR. Fabricated membranes were tested for dry and wet mechanical properties. Fibroblasts and preosteoblasts were seeded into the membranes and rates and patterns of proliferation were analyzed using a kit-8 assay and by scanning electron microscopy. Osteogenic differentiation was verified by alizarin red S and alkaline phosphatase (ALP staining. An in vivo experiment was performed using an alveolar bone defect beagle model, in which defects in three dogs were covered with different membranes. CT and histological analyses at eight weeks after surgery revealed that 3D-printed PCL/β-TCP membranes were more effective than 3D-printed PCL, and substantially better than conventional collagen membranes in terms of biocompatibility and bone regeneration and, thus, at facilitating GBR.

3D Printing of Calcium Phosphate Ceramics for Bone Tissue Engineering and Drug Delivery

Science.gov (United States)

Trombetta, Ryan; Inzana, Jason A.; Schwarz, Edward M.; Kates, Stephen L.; Awad, Hani A.

2016-01-01

Additive manufacturing, also known as 3D printing, has emerged over the past 3 decades as a disruptive technology for rapid prototyping and manufacturing. Vat polymerization, powder bed fusion, material extrusion, and binder jetting are distinct technologies of additive manufacturing, which have been used in a wide variety of fields, including biomedical research and tissue engineering. The ability to print biocompatible, patient-specific geometries with controlled macro- and micropores, and to incorporate cells, drugs and proteins has made 3D-printing ideal for orthopaedic applications, such as bone grafting. Herein, we performed a systematic review examining the fabrication of calcium phosphate (CaP) ceramics by 3D printing, their biocompatibility in vitro, and their bone regenerative potential in vivo, as well as their use in localized delivery of bioactive molecules or cells. Understanding the advantages and limitations of the different 3D printing approaches, CaP materials, and bioactive additives through critical evaluation of in vitro and in vivo evidence of efficacy is essential for developing new classes of bone graft substitutes that can perform as well as autografts and allografts or even surpass the performance of these clinical standards. PMID:27324800

3D Printing of Calcium Phosphate Ceramics for Bone Tissue Engineering and Drug Delivery.

Science.gov (United States)

Trombetta, Ryan; Inzana, Jason A; Schwarz, Edward M; Kates, Stephen L; Awad, Hani A

2017-01-01

Additive manufacturing, also known as 3D printing, has emerged over the past 3 decades as a disruptive technology for rapid prototyping and manufacturing. Vat polymerization, powder bed fusion, material extrusion, and binder jetting are distinct technologies of additive manufacturing, which have been used in a wide variety of fields, including biomedical research and tissue engineering. The ability to print biocompatible, patient-specific geometries with controlled macro- and micro-pores, and to incorporate cells, drugs and proteins has made 3D-printing ideal for orthopaedic applications, such as bone grafting. Herein, we performed a systematic review examining the fabrication of calcium phosphate (CaP) ceramics by 3D printing, their biocompatibility in vitro, and their bone regenerative potential in vivo, as well as their use in localized delivery of bioactive molecules or cells. Understanding the advantages and limitations of the different 3D printing approaches, CaP materials, and bioactive additives through critical evaluation of in vitro and in vivo evidence of efficacy is essential for developing new classes of bone graft substitutes that can perform as well as autografts and allografts or even surpass the performance of these clinical standards.

Trehalose-6-Phosphate: connecting plant metabolism and development

Directory of Open Access Journals (Sweden)

Jathish ePonnu

2011-11-01

Full Text Available Beyond their metabolic roles, sugars can also act as messengers in signal transduction. Trehalose, a sugar found in many species of plants and animals, is a non-reducing disaccharide composed of two glucose moieties. Its synthesis in plants is a two-step process, involving the production of trehalose-6-phosphate (T6P catalyzed by TREHALOSE-6-PHOSPHATE SYNTHASE (TPS and its consecutive dephosphorylation to trehalose, catalyzed by TREHALOSE-6-PHOSPHATE PHOSPHATASE (TPP. T6P has recently emerged as an important signaling metabolite, regulating carbon assimilation and sugar status in plants. In addition, T6P has also been demonstrated to play an essential role in plant development. This review recapitulates the recent advances in our understanding the role of T6P in coordinating diverse metabolic and developmental processes.

Comparative Efficacies of Collagen-Based 3D Printed PCL/PLGA/?-TCP Composite Block Bone Grafts and Biphasic Calcium Phosphate Bone Substitute for Bone Regeneration

OpenAIRE

Hwang, Kyoung-Sub; Choi, Jae-Won; Kim, Jae-Hun; Chung, Ho Yun; Jin, Songwan; Shim, Jin-Hyung; Yun, Won-Soo; Jeong, Chang-Mo; Huh, Jung-Bo

2017-01-01

The purpose of this study was to compare bone regeneration and space maintaining ability of three-dimensional (3D) printed bone grafts with conventional biphasic calcium phosphate (BCP). After mixing polycaprolactone (PCL), poly (lactic-co-glycolic acid) (PLGA), and ?-tricalcium phosphate (?-TCP) in a 4:4:2 ratio, PCL/PLGA/?-TCP particulate bone grafts were fabricated using 3D printing technology. Fabricated particulate bone grafts were mixed with atelocollagen to produce collagen-based PCL/P...

Biosynthesis of a 3,6-dideoxyhexose: crystallization and X-ray diffraction of CDP-6-deoxy-l-threo-d-glycero-4-hexulose-3-dehydrase (E1) for ascarylose biosynthesis

International Nuclear Information System (INIS)

Smith, Peter; Lin, Ava; Szu, Ping-hui; Liu, Hung-wen; Tsai, Shiou-Chuan

2006-01-01

E 1 dehydrase, which is important in the biosynthesis of the 3,6-dideoxy sugar ascarylose and is the only known PMP-containing enzyme to carry out one-electron chemistry, has been crystallized and diffracted to 1.9 Å. CDP-6-deoxy-l-threo-d-glycero-4-hexulose-3-dehydrase (E 1 ), along with its reductase (E 3 ), catalyzes the unusual C-3 deoxygenation of CDP-6-deoxy-l-threo-d-glycero-4-hexulose to form CDP-3,6-dideoxy-l-threo-d-glycero-4-hexulose in CDP-ascarylose biosynthesis [Chen et al. (1996 ▶), Biochemistry, 35, 16412–16420]. This dimeric [2Fe–2S] protein, cloned from the bacteria Yersinia pseudotuberculosis, is currently the only known example of an enzyme that uses a vitamin B 6 -derived pyridoxamine 5′-phosphate (PMP) cofactor to carry out one-electron chemistry [Agnihotri & Liu (2001 ▶), Bioorg. Chem.29, 234–257]. It also exhibits a [2Fe–2S] cluster-binding motif (C-X 57 -C-X 1 -C-X 7 -C) which has not been observed previously [Agnihotri et al. (2004 ▶), Biochemistry, 43, 14265–14274] The recombinant 97.7 kDa dimer was crystallized in the trigonal space group P3 2 , with unit-cell parameters a = b = 97.37, c = 142.2 Å, α = β = 90, γ = 120°. A data set has been collected to 1.9 Å resolution. A full MAD data set was also collected at the iron absorption edge that diffracted to 2.0 Å

Complex formation between uranium(VI) and α-D-glucose 1-phosphate

International Nuclear Information System (INIS)

Koban, A.; Geipel, G.; Bernhard, G.

2003-01-01

The complex formation of uranium(VI) with α-D-glucose 1-phosphate (C 6 H 11 O 6 PO 3 2- , G1P) was determined by time-resolved laser-induced fluorescence spectroscopy (TRLFS) at pH 4 and potentiometric titration in the pH range from 3 to 10. Both measurements show the formation of a 1 : 1 complex at lower pH values. The formation constant of UO 2 (C 6 H 11 O 6 PO 3 ) was calculated from TRLFS measurements to be log β 11 = 5.72±0.12, and from potentiometric titration log β 11 = 5.40±0.25, respectively. It was found by potentiometric titration that at higher pH values the complexation changes to a 1 : 2 complex. The stability constant for this complex was calculated to be log β 12 = 8.96±0.18. (orig.)

Influence of phosphates when uranium in solutions obtained by attacking Forez with sulfuric acid is precipitated by the action of lime; Influence des phosphates, lors de la precipitation par la chaux, de l'uranium contenu dans les solutions d'attaque sulfurique du Forez

Energy Technology Data Exchange (ETDEWEB)

Brebec, G

1959-03-01

Influence of phosphates when uranium in solutions obtained by attacking Forez with sulfuric acid is precipitated by the action of lime was studied. Most of the phosphates were eliminated in the form of ferric phosphates without noticeable losses of uranium: for this it is only necessary to add sufficient ferric sulfate to the solution to be treated so that [Po{sub 4}{sup 3-}]/[Fe{sup 3+}] {approx} 0,4. In these conditions, the preparation of a calcium concentrate rich in uranium takes place in two stages. The first is neutralization at pH 2,7 to 2,8 with elimination of phosphates, sulfates and iron; the second is precipitation of the concentrate at pH 6,5. (author) [French] Nous avons reussi a eliminer la majeure partie des phosphates sous forme de phosphates ferriques, sans pertes sensibles d'uranium. Pour cela, il suffit d'ajouter a la solution a traiter, du sulfate ferrique en quantite telle que: (Po{sub 4}{sup 3-}]/[Fe{sup 3+}] {approx} 0,4. Dans ces conditions, la preparation du concentre calcique, riche en uranium, s'effectue normalement en deux temps: 1) preneutralisation a pH 2,7-2,8: elimination des sulfates, phosphates et fer; 2) precipitation du concentre a pH 6,5. (auteur)

Reduction of nucleotides by ionizing radiation: uridine 5' phosphate, and cytidine 3' phosphate

International Nuclear Information System (INIS)

Box, H.C.; Potter, W.R.; Budzinski, E.E.

1974-01-01

Anions formed by the addition of an electron to the uracil base were observed in single crystals of the barium salt of uridine 5' phosphate x irradiated at 4.2 0 K. The hyperfine coupling tensor for the C 6 -H proton was deduced from ENDOR measurements; the principal values are -59.12, -32.92 and -16.24 MHz. Similar measurements were made on single crystals of cytidine 3' phosphate. The principal values for the C 6 -H proton hyperfine coupling in the anion formed on the cytosine base are -59.26, -33.98 and -14.68 MHz. (U.S.)

miRNA778 and SUVH6 are involved in phosphate homeostasis in Arabidopsis.

Science.gov (United States)

Wang, Lei; ZengJ, Hou Qing; Song, Jun; Feng, Sheng Jun; Yang, Zhi Min

2015-09-01

microRNAs (miRNAs) play an important role in plant adaptation to phosphate (Pi) starvation. Histone methylation can remodel chromatin structure and mediate gene expression. This study identified Arabidopsis miR778, a Pi-responsive miRNA, and its target gene Su(var) 3-9 homologs 6 (SUVH6) encoding a histone H3 lysine 9 (H3K9) methyltransferase. Overexpression of miR778 moderately enhanced primary and lateral root growth, free phosphate accumulation in shoots, and accumulation of anthocyanin under Pi deficient conditions. miR778 overexpression relieved the arrest of columella cell development under Pi starvation. Conversely, transgenic plants overexpressing a miR778-target mimic (35S::MIM778), that act as a sponge and sequesters miR778, showed opposite phenotypes of 35S::miR778 plants under Pi deficiency. Expression of several Pi deficiency-responsive genes such as miR399, Phosphate Transporter (PHT1;4), Low Phosphate-Resistant1 (LPR1) and Production of Anthocyanin Pigment 1 (PAP1) were elevated in the miR778 overexpressing plants, suggesting that both miR778 and SUVH6 are involved in phosphate homeostasis in plants. This study has provided a basis for further investigation on how SUVH6 regulates its downstream genes through chromatin remodeling and DNA methylation in plants stressed by Pi deficiency. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Syntheses of 24R,25-dihydroxy-[6,19,19-3H]vitamin D3 and 24R,25-dihydroxy-[6,19,19-2H]vitamin D3

International Nuclear Information System (INIS)

Yamada, S.; Shimizu, M.; Fukushima, K.; Niimura, K.; Maeda, Y.

1989-01-01

24R,25-Dihydroxy-[6,19,19-3H]vitamin D3 with a specific activity of 54 Ci/mmol and 24R,25-dihydroxy-[6,19,19-2H]vitamin D3 with 2.6 deuterium atoms/mol were synthesized in four steps starting from 24R,25-Dihydroxyvitamin D3 via its sulfur dioxide adduct

Direct 3D powder printing of biphasic calcium phosphate scaffolds for substitution of complex bone defects

International Nuclear Information System (INIS)

Castilho, Miguel; Pires, Inês; Moseke, Claus; Ewald, Andrea; Gbureck, Uwe; Groll, Jürgen; Teßmar, Jörg; Vorndran, Elke

2014-01-01

The 3D printing technique based on cement powders is an excellent method for the fabrication of individual and complex bone substitutes even in the case of large defects. The outstanding bone remodeling capacity of biphasic calcium phosphates (BCPs) containing hydroxyapatite (HA) as well as tricalcium phosphate (TCP) in varying ratios makes the adaption of powder systems resulting in BCP materials to this fabrication technique a desirable aim. This study presents the synthesis and characterization of a novel powder system for the 3D printing process, intended for the production of complexly shaped BCP scaffolds by a hydraulic setting reaction of calcium carbonate and TCP with phosphoric acid. The HA/TCP ratio in the specimens could be tailored by the calcium/phosphate ratio of the starting powder. The scaffolds could be fabricated with a dimensional accuracy of >96.5% and a minimal macro pore size of 300 µm. Independent of the phase composition the printed specimens showed a microporosity of approximately 68%, while the compressive strength strongly depended on the chemical composition and increased with rising TCP content in the scaffolds to a maximum of 1.81 MPa. Post-treatment of the scaffolds with a polylactic-co-glycolic acid-solution enhanced the mechanical properties by a factor of 8. In vitro studies showed that all BCP scaffolds were cytocompatible and enhanced the cell viability as well as the cell proliferation, as compared with pure TCP. Cell proliferation is even better on BCP when compared to HA and cell viability is in a similar range on these materials. (paper)

Thermodynamic and microscopic equilibrium constants of molecular species formed from pyridoxal 5'-phosphate and 2-amino-3-phosphonopropionic acid in aqueous and D2O solution

International Nuclear Information System (INIS)

Szpoganicz, B.; Martell, A.E.

1984-01-01

Schiff base formation between pyridoxal 5'-phosphate (PLP) and 2-amino-3-phosphonopropionic acid (APP) has been investigated by measurement of the corresponding NMR and electronic absorption spectra. A value of 0.26 was found for the formation constant of the completely deprotonated Schiff base species, and is much smaller than the values reported for pyridoxal-β-chloroalanine and pyridoxal-O-phosphoserine. The protonation constants for the aldehyde and hydrate forms of PLP were determined in D 2 O by measurement of the variation of chemical shifts with pD (pH in D 2 O). The hydration constants of PLP were determined in a pD range 2-12, and species distributions were calculated. The protonation constants of the APP-PLP Schiff base determined by NMR in D 2 O were found to have the log values 12.54, 8.10, 6.70, and 5.95, and the species distributions were calculated for a range of pD values. Evidence is reported for hydrogen bonding involving the phosphate and phosphonate groups of the diprotonated Schiff base. The cis and trans forms of the Schiff bases were distinguished with the aid of the nuclear Overhauser effect. 43 references, 9 figures, 3 tables

Rv3634c from Mycobacterium tuberculosis H37Rv encodes an enzyme with UDP-Gal/Glc and UDP-GalNAc 4-epimerase activities.

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Peehu Pardeshi

Full Text Available A bioinformatics study revealed that Mycobacterium tuberculosis H37Rv (Mtb contains sequence homologs of Campylobacter jejuni protein glycosylation enzymes. The ORF Rv3634c from Mtb was identified as a sequence homolog of C. jejuni UDP-Gal/GalNAc 4-epimerase. This study reports the cloning of Rv3634c and its expression as an N-terminal His-tagged protein. The recombinant protein was shown to have UDP-Gal/Glc 4-epimerase activity by GOD-POD assay and by reverse phase HPLC. This enzyme was shown to have UDP-GalNAc 4-epimerase activity also. Residues Ser121, Tyr146 and Lys150 were shown by site-directed mutagenesis to be important for enzyme activity. Mutation of Ser121 and Tyr146 to Ala and Phe, respectively, led to complete loss of activity whereas mutation of Lys150 to Arg led to partial loss of activity. There were no gross changes in the secondary structures of any of these three mutants. These results suggest that Ser121 and Tyr146 are essential for epimerase activity of Rv3634c. UDP-Gal/Glc 4-epimerases from other organisms also have a catalytic triad consisting of Ser, Tyr and Lys. The triad carries out proton transfer from nucleotide sugar to NAD+ and back, thus effecting the epimerization of the substrate. Addition of NAD+ to Lys150 significantly abrogates the loss of activity, suggesting that, as in other epimerases, NAD+ is associated with Rv3634c.

N-acetylglucosamine 2-Epimerase from Pedobacter heparinus: First Experimental Evidence of a Deprotonation/Reprotonation Mechanism

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Su-Yan Wang

2016-12-01

Full Text Available The control of cellular N-acetylmannosamine (ManNAc levels has been postulated to be an effective way to modulate the decoration of cell surfaces with sialic acid. N-acetylglucosamine 2-epimerase catalyzes the interconversion of N-acetylglucosamine (GlcNAc and ManNAc. Herein, we describe the cloning, expression, purification and biochemical characterization of an unstudied N-acetylglucosamine 2-epimerase from Pedobacter heparinus (PhGn2E. To further characterize the enzyme, several N-acylated glucosamine derivatives were chemically synthesized, and subsequently used to test the substrate specificity of PhGn2E. Furthermore, NMR studies of deuterium/hydrogen exchange at the anomeric hydroxy group and C-2 positions of the substrate in the reaction mixture confirmed for the first time the postulated epimerization reaction via ring-opening/enolate formation. Site-directed mutagenesis of key residues in the active site showed that Arg63 and Glu314 are directly involved in proton abstraction and re-incorporation onto the substrate. As all mechanistically relevant active site residues also occur in all mammalian isoforms, PhGn2E can serve as a model N-acetylglucosamine 2-epimerase for further elucidation of the active site mechanism in these enzymes.

Concentration dependent spectroscopic properties of Dy3+ ions doped boro-phosphate glasses

Science.gov (United States)

Mariyappan, M.; Marimuthu, K.

2016-05-01

Dy3+ ions doped boro-phosphate glasses have been synthesized by melt quenching method and characterized through FTIR, absorption and luminescence spectral measurements. The presence of various stretching and bending vibrations of different borate and phosphate groups were identified from the FTIR spectra. In order to examine the electronic band structure of the studied glasses, Optical energy gap (Eopt) and Urbach energy (ΔE) values were estimated from the absorption spectra. The Judd-Ofelt (JO) intensity parameters were calculated to examine the symmetry of the ligand environment around the Dy3+ ions site. The emission spectra exhibit two intense emission bands at around 482 nm (blue) and 574 nm (yellow) corresponding to the 4F9/2→6H15/2 and 4F9/2→6H13/2 transitions respectively. The emission spectra were characterized through Commission International d'Eclairage (CIE) 1931 chromaticity diagram to explore its suitability for WLED applications.

Concentration effect on the spectroscopic behavior of Tb3+ ions in zinc phosphate glasses

International Nuclear Information System (INIS)

Kesavulu, C.R.; Almeida Silva, Anielle Christine; Dousti, M.R.; Dantas, Noelio Oliveira; Camargo, A.S.S. de; Catunda, Tomaz

2015-01-01

Zinc phosphate glasses (PZABPTb) in the compositional system: P 2 O 5 –ZnO–Al 2 O 3 –BaO–PbO doped with variable Tb 3+ concentrations (1–5 wt% Tb 2 O 3 ) were prepared and characterized through absorption, excitation, emission and intensity decay rate measurements. The Judd–Ofelt model has been adopted to evaluate the radiative properties of the 5 D 4 → 7 F 6–3 emission transitions. The effect of Tb 3+ ion concentration on the emissions from the 5 D 3,4 excited levels is discussed in detail. Analysis of the intensity decay curves corresponding to blue and green emissions from levels 5 D 3 and 5 D 4 , respectively, allowed determination of effective lifetimes, which confirmed the Tb 3+ ion concentration quenching of the blue emission in these glasses. The decay curves for the 5 D 3 level are found to be non-exponential in nature for all the studied concentrations due to ion–ion energy transfer through cross-relaxation. In an attempt to identify the origin of the energy transfer mechanism, the decay curves were well fitted to the Inokuti–Hirayama model for S=6, which indicates that the energy transfer process is of dipole–dipole type. The optical band gap energy (E opt ) has been evaluated taking into account the ultraviolet edge of absorption spectra. - Highlights: • Tb 3+ -doped zinc phosphate glasses have been prepared by melt quenching technique. • Spectroscopic parameters were evaluated using the Judd–Ofelt theory. • Effects of Tb 3+ concentration on luminescence of the glasses were studied. • Strong intense laser transition for Tb 3+ ion in PZABPTb glasses is 5 D 4 → 7 F 5 (0.54 μm). • PZABPTb glasses could be used in the development of green color display devices and solid state visible lasers

Improved Xylitol Production from D-Arabitol by Enhancing the Coenzyme Regeneration Efficiency of the Pentose Phosphate Pathway in Gluconobacter oxydans.

Science.gov (United States)

Li, Sha; Zhang, Jinliang; Xu, Hong; Feng, Xiaohai

2016-02-10

Gluconobacter oxydans is used to produce xylitol from D-arabitol. This study aims to improve xylitol production by increasing the coenzyme regeneration efficiency of the pentose phosphate pathway in G. oxydans. Glucose-6-phosphate dehydrogenase (G6PDH) and 6-phosphogluconate dehydrogenase (6PGDH) were overexpressed in G. oxydans. Real-time PCR and enzyme activity assays revealed that G6PDH/6PGDH activity and coenzyme regeneration efficiency increased in the recombinant G. oxydans strains. Approximately 29.3 g/L xylitol was obtained, with a yield of 73.2%, from 40 g/L d-arabitol in the batch biotransformation with the G. oxydans PZ strain. Moreover, the xylitol productivity (0.62 g/L/h) was 3.26-fold of the wild type strain (0.19 g/L/h). In repetitive batch biotransformation, the G. oxydans PZ cells were used for five cycles without incurring a significant loss in productivity. These results indicate that the recombinant G. oxydans PZ strain is economically feasible for xylitol production in industrial bioconversion.

Synthesis, crystal structure and spectroscopy properties of Na 3AZr(PO 4) 3 ( A=Mg, Ni) and Li 2.6Na 0.4NiZr(PO 4) 3 phosphates

Science.gov (United States)

Chakir, M.; El Jazouli, A.; de Waal, D.

2006-06-01

Na 3AZr(PO 4) 3 ( A=Mg, Ni) phosphates were prepared at 750 °C by coprecipitation route. Their crystal structures have been refined at room temperature from X-ray powder diffraction data using Rietveld method. Li 2.6Na 0.4NiZr(PO 4) 3 was synthesized through ion exchange from the sodium analog. These materials belong to the Nasicon-type structure. Raman spectra of Na 3AZr(PO 4) 3 ( A=Mg, Ni) phosphates present broad peaks in favor of the statistical distribution in the sites around PO 4 tetrahedra. Diffuse reflectance spectra indicate the presence of octahedrally coordinated Ni 2+ ions.

The reduction of nucleotides by ionizing radiation: uridine 5' phosphate and cytidine 3' phosphate

International Nuclear Information System (INIS)

Box, H.C.; Potter, W.R.; Budzinski, E.E.

1975-01-01

Anions formed by the addition of an electron to the uracil base were observed in single crystals of the barium salt of uridine 5' phosphate x-irradiated at 4.2 degreeK. The hyperfine coupling tensor for the C 6 --H proton was deduced from ENDOR measurements; the principal values are -59.12, -32.92, and -16.24 MHz. Similar measurements were made on single crystals of cytidine 3' phosphate. The principal values for the C 6 --H proton hyperfine coupling in the anion formed on the cytosine base are -59.26, -33.98, and -14.68 MHz

Isolation and Characterization of D-Myo-Inositol-3-Phosphate Synthase Gene Family Members in Soybean

OpenAIRE

Good, Laura Lee

2001-01-01

The objective of this research was to isolate genes encoding isoforms of the enzyme D-myo-inositol 3-phosphate synthase (MIPS, E.C. 5.5.1.4) from soybean and to characterize their expression, especially with respect to their involvement in phytic acid biosynthesis. A MIPS-homologous cDNA, designated GmMIPS1, was isolated via PCR using total RNA from developing seeds. Southern blot analysis and examination of MIPS-homologous soybean EST sequences suggested that GmMIPS1 is part of a multigene...

Glucose-6-Phosphate Dehydrogenase (G6PD) deficiency in patients ...

African Journals Online (AJOL)

This is a study of Glucose-6-phosphate dehydrogenase(G6PD) deficiency in sickle cell anaemia patients attending the haematology clinic of the Jos University Teaching Hospital (JUTH), Jos- Nigeria. The prevalence of G6PD deficiency among the 130 sickle cell anaemia patients studied was found to be 18.5%. G6PD ...

Characterization and molecular modeling of Inositol 1,3,4 tris phosphate 5/6 kinase-2 from Glycine max (L) Merr.: comprehending its evolutionary conservancy at functional level.

Science.gov (United States)

Marathe, Ashish; Krishnan, Veda; Mahajan, Mahesh M; Thimmegowda, Vinutha; Dahuja, Anil; Jolly, Monica; Praveen, Shelly; Sachdev, Archana

2018-01-01

Soybean genome encodes a family of four inositol 1,3,4 trisphosphate 5/6 kinases which belong to the ATP-GRASP group of proteins. Inositol 1,3,4 trisphosphate kinase-2 ( GmItpk2 ), catalyzing the ATP-dependent phosphorylation of Inositol 1,3,4 trisphosphate (IP3) to Inositol 1,3,4,5 tetra phosphate or Inositol 1,3,4,6 tetra phosphate, is a key enzyme diverting the flux of inositol phosphate pool towards phytate biosynthesis. Although considerable research on characterizing genes involved in phytate biosynthesis is accomplished at genomic and transcript level, characterization of the proteins is yet to be explored. In the present study, we report the isolation and expression of single copy Itpk 2 (948 bp) from Glycine max cv Pusa-16 predicted to encode 315 amino acid protein with an isoelectric point of 5.9. Sequence analysis revealed that Gm ITPK2 shared highest similarity (80%) with Phaseolus vulgaris. The predicted 3D model confirmed 12 α helices and 14 β barrel sheets with ATP-binding site close to β sheet present towards the C-terminus of the protein molecule. Spatio-temporal transcript profiling signified GmItpk2 to be seed specific, with higher transcript levels in the early stage of seed development. The present study using various molecular and bio-computational tools could, therefore, help in improving our understanding of this key enzyme and prove to be a potential target towards generating low phytate trait in nutritionally rich crop like soybean.

Thermostability enhancement of cellobiose 2-epimerase from Caldicellulosiruptor saccharolyticus by site-directed mutagenesis

Science.gov (United States)

Cellobiose 2-epimerase from the thermophile Caldicellulosiruptor saccharolyticus (CsCE) catalyzes the isomerization of lactose into lactulose, a non-digestible disaccharide widely used in food and pharmaceutical industries. Semi-rational approaches were applied to enhance the thermostability of CsCE...

Glucose 6-phosphate dehydrogenase variants in Japan.

Science.gov (United States)

Miwa, S

1980-01-01

Fifty-four cases of glucose 6-phosphate dehydrogenase (G6PD) deficiency have so far been reported in Japan. Among them, 21 G6PD variants have been characterized. Nineteen out of the 21 variants were characterized in our laboratory and G6PD Heian and "Kyoto" by others. G6PD Tokyo, Tokushima, Ogikubo, Kurume, Fukushima, Yokohama, Yamaguchi, Wakayama, Akita, Heian and "Kyoto" were classified as Class 1, because all these cases showed chronic hemolytic anemia and severe enzyme deficiency. All these variants showed thermal instability. G6PD Mediterranean-like, Ogori, Gifu and Fukuoka were classified as Class 2, whereas G6PD Hofu, B(-) Chinese, Ube, Konan, Kamiube and Kiwa belonged to Class 3. All the 6 Class 3 variants were found as the results of the screening tests. The incidence of the deficiency in Japanese seems to be 0.1-0.5% but that of the cases which may slow drug-induced hemolysis would be much less. G6PD Ube and Konan appear to be relatively common in Japan.

Three new d10 transition metal selenites containing PO4 tetrahedron: Cd7(HPO4)2(PO4)2(SeO3)2, Cd6(PO4)1.34(SeO3)4.66 and Zn3(HPO4)(SeO3)2(H2O)

Science.gov (United States)

Ma, Yun-Xiang; Gong, Ya-Ping; Hu, Chun-li; Mao, Jiang-Gao; Kong, Fang

2018-06-01

Three new d10 transition metal selenites containing PO4 tetrahedron, namely, Cd7(HPO4)2(PO4)2(SeO3)2 (1), Cd6(PO4)1.34(SeO3)4.66 (2) and Zn3(HPO4)(SeO3)2(H2O) (3), have been synthesized by hydrothermal reaction. They feature three different structural types. Compound 1 exhibits a novel 3D network composed of 3D cadmium selenite open framework with phosphate groups filled in the 1D helical tunnels. The structure of compound 2 displays a new 3D framework consisted of 2D cadmium oxide layers bridged by SeO3 and PO4 groups. Compound 3 is isostructural with the reported solids of Co3(SeO3)3-x(PO3OH)x(H2O) when x is equal to 1.0. Its structure could be viewed as a 3D zinc oxide open skeleton with SeO3 and HPO4 polyhedra attached on the wall of the tunnels. They represent the only examples in metal selenite phosphates in addition to the above cobalt compounds. Optical diffuse reflectance spectra revealed that these solids are insulators, which are consistent with the results of band structure computations based on DFT algorithm.

Synthesis and crystal structure of 4-fluorobenzylammonium dihydrogen phosphate, [FC6H4CH2NH3]H2PO4

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Ali Rayes

2016-12-01

Full Text Available The asymmetric unit of the title salt, [p-FC6H4CH2NH3]+·H2PO4−, contains one 4-fluorobenzylammonium cation and one dihydrogen phosphate anion. In the crystal, the H2PO4− anions are linked by O—H...O hydrogen bonds to build corrugated layers extending parallel to the ab plane. The FC6H4CH2NH3+ cations lie between these anionic layers to maximize the electrostatic interactions and are linked to the H2PO4− anions through N—H...O hydrogen bonds, forming a three-dimensional supramolecular network. Two hydrogen atoms belonging to the dihydrogen phosphate anion are statistically occupied due to disorder along the OH...HO direction.

Two tomato GDP-D-mannose epimerase isoforms involved in ascorbate biosynthesis play specific roles in cell wall biosynthesis and development.

Science.gov (United States)

Mounet-Gilbert, Louise; Dumont, Marie; Ferrand, Carine; Bournonville, Céline; Monier, Antoine; Jorly, Joana; Lemaire-Chamley, Martine; Mori, Kentaro; Atienza, Isabelle; Hernould, Michel; Stevens, Rebecca; Lehner, Arnaud; Mollet, Jean Claude; Rothan, Christophe; Lerouge, Patrice; Baldet, Pierre

2016-08-01

GDP-D-mannose epimerase (GME, EC 5.1.3.18) converts GDP-D-mannose to GDP-L-galactose, and is considered to be a central enzyme connecting the major ascorbate biosynthesis pathway to primary cell wall metabolism in higher plants. Our previous work demonstrated that GME is crucial for both ascorbate and cell wall biosynthesis in tomato. The aim of the present study was to investigate the respective role in ascorbate and cell wall biosynthesis of the two SlGME genes present in tomato by targeting each of them through an RNAi-silencing approach. Taken individually SlGME1 and SlGME2 allowed normal ascorbate accumulation in the leaf and fruits, thus suggesting the same function regarding ascorbate. However, SlGME1 and SlGME2 were shown to play distinct roles in cell wall biosynthesis, depending on the tissue considered. The RNAi-SlGME1 plants harbored small and poorly seeded fruits resulting from alterations of pollen development and of pollination process. In contrast, the RNAi-SlGME2 plants exhibited vegetative growth delay while fruits remained unaffected. Analysis of SlGME1- and SlGME2-silenced seeds and seedlings further showed that the dimerization state of pectin rhamnogalacturonan-II (RG-II) was altered only in the RNAi-SlGME2 lines. Taken together with the preferential expression of each SlGME gene in different tomato tissues, these results suggest sub-functionalization of SlGME1 and SlGME2 and their specialization for cell wall biosynthesis in specific tomato tissues. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

The pentose phosphate pathway in Trypanosoma cruzi: a potential target for the chemotherapy of Chagas disease

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Mariana Igoillo-Esteve

2007-12-01

Full Text Available Trypanosoma cruzi is highly sensitive to oxidative stress caused by reactive oxygen species. Trypanothione, the parasite's major protection against oxidative stress, is kept reduced by trypanothione reductase, using NADPH; the major source of the reduced coenzyme seems to be the pentose phosphate pathway. Its seven enzymes are present in the four major stages in the parasite's biological cycle; we have cloned and expressed them in Escherichia coli as active proteins. Glucose 6-phosphate dehydrogenase, which controls glucose flux through the pathway by its response to the NADP/NADPH ratio, is encoded by a number of genes per haploid genome, and is induced up to 46-fold by hydrogen peroxide in metacyclic trypomastigotes. The genes encoding 6-phosphogluconolactonase, 6-phosphogluconate dehydrogenase, transaldolase and transketolase are present in the CL Brener clone as a single copy per haploid genome. 6-phosphogluconate dehydrogenase is very unstable, but was stabilized introducing two salt bridges by site-directed mutagenesis. Ribose-5-phosphate isomerase belongs to Type B; genes encoding Type A enzymes, present in mammals, are absent. Ribulose-5-phosphate epimerase is encoded by two genes. The enzymes of the pathway have a major cytosolic component, although several of them have a secondary glycosomal localization, and also minor localizations in other organelles.Trypanosoma cruzi é altamente sensível ao estresse oxidativo causado por espécies reativas do oxigênio. Tripanotiona, o principal protetor do parasita contra o estresse oxidativo, é mantido reduzido pela tripanotiona redutase, pela presença deNADPH; a principal fonte da coenzima reduzida parece ser a via da pentose fosfato. As sete enzimas dessa via estão presentes nos quatro principais estágios do ciclo biológico do parasita; nós clonamos e expressamos as enzimas em Escherichia coli como proteínas ativas. Glucose 6-fosfato desidrogenase, que controla o fluxo da glucose da

Post-translational modification of ribosomally synthesized peptides by a radical SAM epimerase in Bacillus subtilis

Science.gov (United States)

Benjdia, Alhosna; Guillot, Alain; Ruffié, Pauline; Leprince, Jérôme; Berteau, Olivier

2017-07-01

Ribosomally synthesized peptides are built out of L-amino acids, whereas D-amino acids are generally the hallmark of non-ribosomal synthetic processes. Here we show that the model bacterium Bacillus subtilis is able to produce a novel type of ribosomally synthesized and post-translationally modified peptide that contains D-amino acids, and which we propose to call epipeptides. We demonstrate that a two [4Fe-4S]-cluster radical S-adenosyl-L-methionine (SAM) enzyme converts L-amino acids into their D-counterparts by catalysing Cα-hydrogen-atom abstraction and using a critical cysteine residue as the hydrogen-atom donor. Unexpectedly, these D-amino acid residues proved to be essential for the activity of a peptide that induces the expression of LiaRS, a major component of the bacterial cell envelope stress-response system. Present in B. subtilis and in several members of the human microbiome, these epipeptides and radical SAM epimerases broaden the landscape of peptidyl structures accessible to living organisms.

Catalytic Mechanism and Mode of Action of the Periplasmic Alginate Epimerase AlgG

NARCIS (Netherlands)

Wolfram, Francis; Kitova, Elena N.; Robinson, Howard; Walvoort, Marthe T. C.; Codee, Jeroen D. C.; Klassen, John S.; Howell, P. Lynne

2014-01-01

Background: The alginate epimerase AlgG converts mannuronate to its C5 epimer guluronate at the polymer level. Results: The structure of Pseudomonas syringae AlgG has been determined, and the protein has been functionally characterized. Conclusion: His(319) acts as the catalytic base, whereas

Dephosphorylation of 2-deoxyglucose 6-phosphate and 2-deoxyglucose export from cultured astrocytes.

Science.gov (United States)

Forsyth, R J; Bartlett, K; Eyre, J

1996-03-01

Neurotransmitter-stimulated mobilization of astrocyte glycogen has been proposed as a basis for local energy homeostasis in brain. However, uncertainty remains over the fate of astrocyte glycogen. Upon transfer of cultured astrocytes pre-loaded with [2-3H]2-deoxyglucose 6-phosphate at non-tracer concentrations to a glucose-free, 2-deoxyglucose-free medium, rapid dephosphorylation of a proportion of the intracellular 2-deoxyglucose 6-phosphate pool and export of 2-deoxyglucose to the extracellular fluid occurs. Astrocytes show very low, basal rates of gluconeogenesis from pyruvate (approx. 1 nmol mg protein-1 h-1). Astrocytes in vivo may be capable of physiologically significant glucose export from glucose-6-phosphate. The low gluconeogenic activity in astrocytes suggests that the most likely source of glucose-6-phosphate may be glycogen. These findings support the hypothesis that export, as glucose, to adjacent neurons may be one of the possible fate(s) of astrocytic glycogen. Such export of glycogen as glucose occurring in response to increases in neuronal activity could contribute to energy homeostasis on a paracrine scale within brain.

SLC37A1 and SLC37A2 are phosphate-linked, glucose-6-phosphate antiporters.

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Chi-Jiunn Pan

Full Text Available Blood glucose homeostasis between meals depends upon production of glucose within the endoplasmic reticulum (ER of the liver and kidney by hydrolysis of glucose-6-phosphate (G6P into glucose and phosphate (P(i. This reaction depends on coupling the G6P transporter (G6PT with glucose-6-phosphatase-α (G6Pase-α. Only one G6PT, also known as SLC37A4, has been characterized, and it acts as a P(i-linked G6P antiporter. The other three SLC37 family members, predicted to be sugar-phosphate:P(i exchangers, have not been characterized functionally. Using reconstituted proteoliposomes, we examine the antiporter activity of the other SLC37 members along with their ability to couple with G6Pase-α. G6PT- and mock-proteoliposomes are used as positive and negative controls, respectively. We show that SLC37A1 and SLC37A2 are ER-associated, P(i-linked antiporters, that can transport G6P. Unlike G6PT, neither is sensitive to chlorogenic acid, a competitive inhibitor of physiological ER G6P transport, and neither couples to G6Pase-α. We conclude that three of the four SLC37 family members are functional sugar-phosphate antiporters. However, only G6PT/SLC37A4 matches the characteristics of the physiological ER G6P transporter, suggesting the other SLC37 proteins have roles independent of blood glucose homeostasis.

An homolog of the Frz Phosphoenolpyruvate:carbohydrate phosphoTransferase System of extraintestinal pathogenic Escherichia coli is encoded on a genomic island in specific lineages of Streptococcus agalactiae.

Science.gov (United States)

Patron, Kévin; Gilot, Philippe; Camiade, Emilie; Mereghetti, Laurent

2015-06-01

We identified a Streptococcus agalactiae metabolic region (fru2) coding for a Phosphoenolpyruvate:carbohydrate phosphoTransferase System (PTS) homologous to the Frz system of extraintestinal pathogenic Escherichia coli strains. The Frz system is involved in environmental sensing and regulation of the expression of adaptation and virulence genes in E. coli. The S. agalactiae fru2 region codes three subunits of a PTS transporter of the fructose-mannitol family, a transcriptional activator of PTSs of the MtlR family, an allulose-6 phosphate-3-epimerase, a transaldolase and a transketolase. We demonstrated that all these genes form an operon. The fru2 operon is present in a 17494-bp genomic island. We analyzed by multilocus sequence typing a population of 492 strains representative of the S. agalactiae population and we showed that the presence of the fru2 operon is linked to the phylogeny of S. agalactiae. The fru2 operon is always present within strains of clonal complexes CC 1, CC 7, CC 10, CC 283 and singletons ST 130 and ST 288, but never found in other CCs and STs. Our results indicate that the fru2 operon was acquired during the evolution of the S. agalactiae species from a common ancestor before the divergence of CC 1, CC 7, CC 10, CC 283, ST 130 and ST 288. As S. agalactiae strains of CC 1 and CC 10 are frequently isolated from adults with invasive disease, we hypothesize that the S. agalactiae Fru2 system senses the environment to allow the bacterium to adapt to new conditions encountered during the infection of adults. Copyright © 2015 Elsevier B.V. All rights reserved.

Synthesis and characterization of niobium and iron phosphate glasses for U3O8 immobilization

International Nuclear Information System (INIS)

Ghussn, Luciana

2005-01-01

Niobium and iron phosphate glasses were produced by melting inorganic compound mixtures in electric furnaces and microwave ovens. The chemical durability was compared among niobium phosphate glasses produced by both processes, and equivalent results were obtained. Leaching tests were also performed to compare the chemical durability among monolithic glass blocks and sintered glasses. The glass transition, crystallization and melting temperatures as well the Hruby parameter (K H ) and the activation energy for crystallization were determined from differential thermal analysis of niobium phosphate glasses produced in electric furnaces. Niobium phosphate glasses are thermally more stable (K H =0.82 +- 0.04) than iron phosphate glasses (K H = 0.42 +- 0.03). Sintered glasses were produced from particles with different particle size distributions and sintering temperatures in the range of 720 - 800 deg C for niobium phosphate and 530 - 680 deg C for iron phosphate glasses. The sintering process was suitable because a glass with composition 37P 2 O 5 -23K 2 O-40Nb 2 O 5 showing leaching rate of 10 -6 g.cm -2 .d -1 , 99 % of the monolithic density and none crystalline phases was obtained. This glass only crystallizes itself after re heating at temperatures above 800 deg C , showing two crystalline phases identified as KNb 3 O 8 e K 3 NbP 2 O 9 . The activation energies for crystallization are 496 +- 7 kJ/mol and 513 +- 14 kJ/mol. Niobium phosphate sintered glasses are better densified than sintered iron phosphate glasses. The leaching rate of sintered glasses that show open porosity is higher than monolithic glass blocks. This effect is related to an increase of the surface area associated to open porous and, a correction of the value of the surface area used to calculate the leaching rate is required. A model was proposed based on the surface area of spherical porous to take in account that effect. Even after correcting the surface area, the leaching rates of sintered

Chemical Genetic Analysis and Functional Characterization of Staphylococcal Wall Teichoic Acid 2-Epimerases Reveals Unconventional Antibiotic Drug Targets

Energy Technology Data Exchange (ETDEWEB)

Mann, Paul A.; Müller, Anna; Wolff, Kerstin A.; Fischmann, Thierry; Wang, Hao; Reed, Patricia; Hou, Yan; Li, Wenjin; Müller, Christa E.; Xiao, Jianying; Murgolo, Nicholas; Sher, Xinwei; Mayhood, Todd; Sheth, Payal R.; Mirza, Asra; Labroli, Marc; Xiao, Li; McCoy, Mark; Gill, Charles J.; Pinho, Mariana G.; Schneider, Tanja; Roemer, Terry (Merck); (Bonn); (FCT/UNL)

2016-05-04

Here we describe a chemical biology strategy performed in Staphylococcus aureus and Staphylococcus epidermidis to identify MnaA, a 2-epimerase that we demonstrate interconverts UDP-GlcNAc and UDP-ManNAc to modulate substrate levels of TarO and TarA wall teichoic acid (WTA) biosynthesis enzymes. Genetic inactivation of mnaA results in complete loss of WTA and dramatic in vitro β-lactam hypersensitivity in methicillin-resistant S. aureus (MRSA) and S. epidermidis (MRSE). Likewise, the β-lactam antibiotic imipenem exhibits restored bactericidal activity against mnaA mutants in vitro and concomitant efficacy against 2-epimerase defective strains in a mouse thigh model of MRSA and MRSE infection. Interestingly, whereas MnaA serves as the sole 2-epimerase required for WTA biosynthesis in S. epidermidis, MnaA and Cap5P provide compensatory WTA functional roles in S. aureus. We also demonstrate that MnaA and other enzymes of WTA biosynthesis are required for biofilm formation in MRSA and MRSE. We further determine the 1.9Å crystal structure of S. aureus MnaA and identify critical residues for enzymatic dimerization, stability, and substrate binding. Finally, the natural product antibiotic tunicamycin is shown to physically bind MnaA and Cap5P and inhibit 2-epimerase activity, demonstrating that it inhibits a previously unanticipated step in WTA biosynthesis. In summary, MnaA serves as a new Staphylococcal antibiotic target with cognate inhibitors predicted to possess dual therapeutic benefit: as combination agents to restore β-lactam efficacy against MRSA and MRSE and as non-bioactive prophylactic agents to prevent Staphylococcal biofilm formation.

Structure of glycerol-3-phosphate dehydrogenase, an essential monotopic membrane enzyme involved in respiration and metabolism

International Nuclear Information System (INIS)

Yeh, Joanne I.; Chinte, Unmesh; Du, Shoucheng

2008-01-01

Sn-glycerol-3-phosphate dehydrogenase (GlpD) is an essential membrane enzyme, functioning at the central junction of respiration, glycolysis, and phospholipid biosynthesis. Its critical role is indicated by the multitiered regulatory mechanisms that stringently controls its expression and function. Once expressed, GlpD activity is regulated through lipid-enzyme interactions in Escherichia coli. Here, we report seven previously undescribed structures of the fully active E. coli GlpD, up to 1.75 (angstrom) resolution. In addition to elucidating the structure of the native enzyme, we have determined the structures of GlpD complexed with substrate analogues phosphoenolpyruvate, glyceric acid 2-phosphate, glyceraldehyde-3-phosphate, and product, dihydroxyacetone phosphate. These structural results reveal conformational states of the enzyme, delineating the residues involved in substrate binding and catalysis at the glycerol-3-phosphate site. Two probable mechanisms for catalyzing the dehydrogenation of glycerol-3-phosphate are envisioned, based on the conformational states of the complexes. To further correlate catalytic dehydrogenation to respiration, we have additionally determined the structures of GlpD bound with ubiquinone analogues menadione and 2-n-heptyl-4-hydroxyquinoline N-oxide, identifying a hydrophobic plateau that is likely the ubiquinone-binding site. These structures illuminate probable mechanisms of catalysis and suggest how GlpD shuttles electrons into the respiratory pathway. Glycerol metabolism has been implicated in insulin signaling and perturbations in glycerol uptake and catabolism are linked to obesity in humans. Homologs of GlpD are found in practically all organisms, from prokaryotes to humans, with >45% consensus protein sequences, signifying that these structural results on the prokaryotic enzyme may be readily applied to the eukaryotic GlpD enzymes.

Separative recovery with lime of phosphate and fluoride from an acidic effluent containing H3PO4, HF and/or H2SiF6.

Science.gov (United States)

Gouider, Mbarka; Feki, Mongi; Sayadi, Sami

2009-10-30

Fluoride content and flow-rate of fertilizer plant wastewater from phosphoric acid and/or triple superphosphate (TSP) production lead to the discharge of several thousand tons of fluoride (F(-)) per year and even more for phosphate (PO4(3-)). Since sustainability is an important environmental concern, the removal methods should allow phosphorus and fluoride to be recycled as a sustainable products for use as raw materials either in agricultural or industrial applications. In the present work, separative recovery with lime of these two target species was investigated. A preliminary speciation study, carried out on the crude effluent, showed that two forms of fluoride: HF and H2SiF6 are present in a highly acidic medium (pH approximately 2). Evidence that fluoride is present under both free (HF) and combined (H2SiF6) forms, in the phosphate-containing effluent, was provided by comparing potentiometric titration curves of a crude wastewater sample and synthetic acid mixtures containing H3PO4, HF and H2SiF6. In a second step synthetic effluent containing mixtures of the following acids: HF, H2SiF6 and H3PO4, were treated with lime. The behaviour of these compounds under lime treatment was analysed. The data showed that fluoride has a beneficial effect on phosphate removal. Moreover, by acting on the precipitation pH, a "selective" recovery of fluoride and phosphate ions was possible either from phosphoric acid/hydrofluoric acid or phosphoric acid/hexafluorosilicic acid mixtures. Indeed, the first stage of the separative recovery, led to a fluoride removal efficiency of 97-98% from phosphoric acid/hydrofluoric acid mixture. It was of 93-95% from phosphoric acid/hexafluorosilicic acid mixture. During the second stage, the phosphate precipitation reached 99.8% from both acidic mixtures whereas it did not exceed 82% from a solution containing H3PO4 alone. The XRD and IR analyses showed that during lime treatment, a H2SiF6 hydrolysis occurred, instead of CaSiF6 solid

Glucose-6-phosphate mediates activation of the carbohydrate responsive binding protein (ChREBP)

International Nuclear Information System (INIS)

Li, Ming V.; Chen, Weiqin; Harmancey, Romain N.; Nuotio-Antar, Alli M.; Imamura, Minako; Saha, Pradip; Taegtmeyer, Heinrich; Chan, Lawrence

2010-01-01

Carbohydrate response element binding protein (ChREBP) is a Mondo family transcription factor that activates a number of glycolytic and lipogenic genes in response to glucose stimulation. We have previously reported that high glucose can activate the transcriptional activity of ChREBP independent of the protein phosphatase 2A (PP2A)-mediated increase in nuclear entry and DNA binding. Here, we found that formation of glucose-6-phosphate (G-6-P) is essential for glucose activation of ChREBP. The glucose response of GAL4-ChREBP is attenuated by D-mannoheptulose, a potent hexokinase inhibitor, as well as over-expression of glucose-6-phosphatase (G6Pase); kinetics of activation of GAL4-ChREBP can be modified by exogenously expressed GCK. Further metabolism of G-6-P through the two major glucose metabolic pathways, glycolysis and pentose-phosphate pathway, is not required for activation of ChREBP; over-expression of glucose-6-phosphate dehydrogenase (G6PD) diminishes, whereas RNAi knockdown of the enzyme enhances, the glucose response of GAL4-ChREBP, respectively. Moreover, the glucose analogue 2-deoxyglucose (2-DG), which is phosphorylated by hexokinase, but not further metabolized, effectively upregulates the transcription activity of ChREBP. In addition, over-expression of phosphofructokinase (PFK) 1 and 2, synergistically diminishes the glucose response of GAL4-ChREBP. These multiple lines of evidence support the conclusion that G-6-P mediates the activation of ChREBP.

Evaluation of synthase and hemisynthase activities of glucosamine-6-phosphate synthase by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

Science.gov (United States)

Gaucher-Wieczorek, Florence; Guérineau, Vincent; Touboul, David; Thétiot-Laurent, Sophie; Pelissier, Franck; Badet-Denisot, Marie-Ange; Badet, Bernard; Durand, Philippe

2014-08-01

Glucosamine-6-phosphate synthase (GlmS, EC 2.6.1.16) catalyzes the first and rate-limiting step in the hexosamine biosynthetic pathway, leading to the synthesis of uridine-5'-diphospho-N-acetyl-D-glucosamine, the major building block for the edification of peptidoglycan in bacteria, chitin in fungi, and glycoproteins in mammals. This bisubstrate enzyme converts D-fructose-6-phosphate (Fru-6P) and L-glutamine (Gln) into D-glucosamine-6-phosphate (GlcN-6P) and L-glutamate (Glu), respectively. We previously demonstrated that matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) allows determination of the kinetic parameters of the synthase activity. We propose here to refine the experimental protocol to quantify Glu and GlcN-6P, allowing determination of both hemisynthase and synthase parameters from a single assay kinetic experiment, while avoiding interferences encountered in other assays. It is the first time that MALDI-MS is used to survey the activity of a bisubstrate enzyme. Copyright © 2014 Elsevier Inc. All rights reserved.

Screening of Glucose-6-Phosphate Dehydrogenase Deficiency in Cord Blood

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Can Acipayam

2014-02-01

Aim: Glucose-6-phosphate dehydrogenase deficiency is an important factor in etiology of pathologic neonatal jaundice. The aim of this study was to indicate the significance of screening glucose-6-phosphate dehydrogenase deficiency in the cord blood of neonates and the frequency of this deficiency in the etiology of neonatal hyperbilirubinemia. Material and Method: The study was performed consecutive 1015 neonates were included. Five hundred fifty six (54.8% of them were male and 459 (45.2% were female. The following parameters were recorded: Gender, birth weight, birth height, head circumference and gestational age. The glucose-6-phosphate dehydrogenase level of neonates were measured with quantitative method in cord blood. Also, hemoglobine, hematocrite, red blood cell count and blood group were measured. The following parameters were recorded in cases with jaundice: exchange transfusion, phototherapy, physiologic and pathologic jaundice, peak bilirubin day, maximum bilirubin level, total bilirubin level at the first day of jaundice, beginning time of jaundice. Results: Enzyme deficiency was detected in 133 (13.1% of neonates and 76 (57% of them were male, 57 (43% were female. Significant difference was detected in low glucose-6-phosphate dehydrogenase enzyme level with jaundice group for total bilirubin level at the first day of jaundice, maximum total bilirubin level and pathologic jaundice (p<0.05. Discussion: The ratio of glucose-6-phosphate dehydrogenase deficiency was found in Edirne in this study and this ratio was higher than other studies conducted in our country. For this reason, glucose-6-phosphate dehydrogenase enzyme level in cord blood of neonates should be measured routinely and high risk neonates should be followed up for hyperbilirubinemia and parents should be informed in our region.

Enhanced In Vivo Bone and Blood Vessel Formation by Iron Oxide and Silica Doped 3D Printed Tricalcium Phosphate Scaffolds.

Science.gov (United States)

Bose, Susmita; Banerjee, Dishary; Robertson, Samuel; Vahabzadeh, Sahar

2018-05-04

Calcium phosphate (CaP) ceramics show significant promise towards bone graft applications because of the compositional similarity to inorganic materials of bone. With 3D printing, it is possible to create ceramic implants that closely mimic the geometry of human bone and can be custom-designed for unusual injuries or anatomical sites. The objective of the study was to optimize the 3D-printing parameters for the fabrication of scaffolds, with complex geometry, made from synthesized tricalcium phosphate (TCP) powder. This study was also intended to elucidate the mechanical and biological effects of the addition of Fe +3 and Si +4 in TCP implants in a rat distal femur model for 4, 8, and 12 weeks. Doped with Fe +3 and Si +4 TCP scaffolds with 3D interconnected channels were fabricated to provide channels for micronutrients delivery and improved cell-material interactions through bioactive fixation. Addition of Fe +3 into TCP enhanced early-stage new bone formation by increasing type I collagen production. Neovascularization was observed in the Si +4 doped samples after 12 weeks. These findings emphasize that the additive manufacturing of scaffolds with complex geometry from synthesized ceramic powder with modified chemistry is feasible and may serve as a potential candidate to introduce angiogenic and osteogenic properties to CaPs, leading to accelerated bone defect healing.

Cyclic-2,3-diphosphoglycerate levels in Methanobacterium thermoautotrophicum reflect inorganic phosphate availability.

Science.gov (United States)

Seely, R J; Krueger, R D; Fahrney, D E

1983-11-15

Methanobacterium thermoautotrophicum was grown in phosphate-limited chemostat cultures at a dilution rate corresponding to a doubling time of 13.2 h. The cyclic-2,3-diphospho-D-glycerate content of these cells was 8 to 10-fold lower than that of cells grown in batch cultures having a doubling time of 11.5 h. This metabolite accounted for 5% of cell dry weight during batch growth on 2 mM phosphate. In the chemostat the steady-state concentration of phosphate was 4 microM, showing that this methanogen is adapted to highly efficient growth at low phosphate concentrations. Since growth rates were similar in both cultures, the growth rate clearly does not depend on intracellular levels of cyclic-2,3-diphosphoglycerate.

Concentration effect on the spectroscopic behavior of Tb{sup 3+} ions in zinc phosphate glasses

Energy Technology Data Exchange (ETDEWEB)

Kesavulu, C.R., E-mail: crkesavulu2005@gmail.com [Instituto de Fisica de São Carlos, Universidade de São Paulo, Avenida Trabalhador Sãocarlense 400, São Carlos, SP (Brazil); Almeida Silva, Anielle Christine [Laboratorio de Novos Materials Isolantes e Semicondutores (LNMIS), Instituto de Física, Universidade Federal de Uberândia, MG (Brazil); Dousti, M.R. [Instituto de Fisica de São Carlos, Universidade de São Paulo, Avenida Trabalhador Sãocarlense 400, São Carlos, SP (Brazil); Dantas, Noelio Oliveira [Laboratorio de Novos Materials Isolantes e Semicondutores (LNMIS), Instituto de Física, Universidade Federal de Uberândia, MG (Brazil); Camargo, A.S.S. de; Catunda, Tomaz [Instituto de Fisica de São Carlos, Universidade de São Paulo, Avenida Trabalhador Sãocarlense 400, São Carlos, SP (Brazil)

2015-09-15

Zinc phosphate glasses (PZABPTb) in the compositional system: P{sub 2}O{sub 5}–ZnO–Al{sub 2}O{sub 3}–BaO–PbO doped with variable Tb{sup 3+} concentrations (1–5 wt% Tb{sub 2}O{sub 3}) were prepared and characterized through absorption, excitation, emission and intensity decay rate measurements. The Judd–Ofelt model has been adopted to evaluate the radiative properties of the {sup 5}D{sub 4}→{sup 7}F{sub 6–3} emission transitions. The effect of Tb{sup 3+} ion concentration on the emissions from the {sup 5}D{sub 3,4} excited levels is discussed in detail. Analysis of the intensity decay curves corresponding to blue and green emissions from levels {sup 5}D{sub 3} and {sup 5}D{sub 4}, respectively, allowed determination of effective lifetimes, which confirmed the Tb{sup 3+} ion concentration quenching of the blue emission in these glasses. The decay curves for the {sup 5}D{sub 3} level are found to be non-exponential in nature for all the studied concentrations due to ion–ion energy transfer through cross-relaxation. In an attempt to identify the origin of the energy transfer mechanism, the decay curves were well fitted to the Inokuti–Hirayama model for S=6, which indicates that the energy transfer process is of dipole–dipole type. The optical band gap energy (E{sub opt}) has been evaluated taking into account the ultraviolet edge of absorption spectra. - Highlights: • Tb{sup 3+}-doped zinc phosphate glasses have been prepared by melt quenching technique. • Spectroscopic parameters were evaluated using the Judd–Ofelt theory. • Effects of Tb{sup 3+} concentration on luminescence of the glasses were studied. • Strong intense laser transition for Tb{sup 3+} ion in PZABPTb glasses is {sup 5}D{sub 4}→{sup 7}F{sub 5} (0.54 μm). • PZABPTb glasses could be used in the development of green color display devices and solid state visible lasers.

Correlation of viral RNA biosynthesis with glucose-6-phosphate dehydrogenase activity and host resistance

Czech Academy of Sciences Publication Activity Database

Šindelář, Luděk; Šindelářová, Milada

2002-01-01

Roč. 215, - (2002), s. 862-869 ISSN 0032-0935 R&D Projects: GA ČR GA522/99/1264 Institutional research plan: CEZ:AV0Z5038910 Keywords : Glucose 6 phosphate dehydrogenase * Nicotiana (viral infection) * Plant viruses Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.960, year: 2002

Sm3+ and Eu3+ sorption in mixed phosphates of Zr

International Nuclear Information System (INIS)

Contreras R, A.

2011-01-01

The storage of high level radioactive waste in deep geological repositories is an issue of international research in countries with nuclear reactors. A major risk is the groundwater infiltration, which can cause degradation of the containers and leaching the radioactive waste through the different barriers. The study of materials for use as engineered barriers is fundamental, because if dissolution is present, the elements can be captured, ensuring that radioactive materials do not disperse off. The work is divided in four parts, the first describes the techniques developed for the synthesis of phosphates: NaZr 2 (PO 4 ) [NZP] and τ-Zr(Na 0.06 H 0.94 PO 4 ) 2 [TZP-Na], their chemical and morphological characterization, thermal stability and surface area. The obtained NZP shows a diffraction diagram similar to the Jcpds pattern, it has a surface area of 4.9±0.1 m 2 ·g -1 . There are not reports of diffraction patterns for TZP-Na, which has a surface area of 22.9±0.40 m 2 ·g -1 . The hydrogenphosphate obtained, τ-Zr(HPO 4 ) 2 , shows a diffraction diagram similar to that reported by Nor by. The second part presents the physicochemical characterization of the phosphates surface. The constants of formation of surface sites and their distribution were calculated using FITEQL 4.0. The sites surface density (d s ) were determined from potentiometric titration curves of phosphate, hydrogen phosphate and NaClO 4 0.5 M; d s were 3.2 sites nm -2 for NZP and 2.1 sites·nm -2 for TZP-Na. The values of curves formation constants for surface sites were, for NZP: K 1P-O =2, K 2P-O =-7, K 1Zr-O =6.11, K 1Zr-O =7.94, and for TZP-Na: K 1P-O =5.14, K 2P-O =-7.03, K 1Zr-O =2.60, K 1Zr-O =-9.85. The third part of the work reports the samarium and europium sorption curves on phosphate and on hydrogenphosphate at different ph values. The values of the curves were fed on FITEQL 4.0 program and NZP surface complexation constants were obtained. The results for the NZP show, for both

Modulation of agonist-induced inositol phosphate metabolism by cyclic adenosine 3',5'-monophosphate in adrenal glomerulosa cells

International Nuclear Information System (INIS)

Baukal, A.J.; Hunyady, L.; Balla, T.; Ely, J.A.; Catt, K.J.

1990-01-01

Activation of the cAMP messenger system was found to cause specific changes in angiotensin-II (All)-induced inositol phosphate production and metabolism in bovine adrenal glomerulosa cells. Pretreatment of [3H]inositol-labeled glomerulosa cells with 8-bromo-cAMP (8Br-cAMP) caused both short and long term changes in the inositol phosphate response to stimulation by All. Exposure to 8Br-cAMP initially caused dose-dependent enhancement (ED50 = 0.7 microM) of the stimulatory action of All (50 nM; 10 min) on the formation of D-myo-inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] and its immediate metabolites. This effect of 8Br-cAMP was also observed in permeabilized [3H]inositol-labeled glomerulosa cells in which degradation of Ins(1,4,5)P3 was inhibited, consistent with increased activity of phospholipase-C. Continued exposure to 8Br-cAMP for 5-16 h caused selective enhancement of the All-induced increases in D-myo-inositol 1,3,4,6-tetrakisphosphate [Ins(1,3,4,6)P4] and myo-inositol 1,4,5,6-tetrakisphosphate. The long term effect of 8Br-cAMP on the 6-phosphorylated InsP4 isomers, but not the initial enhancement of Ins(1,4,5)P3 formation, was inhibited by cycloheximide. The characteristic biphasic kinetics of All-induced Ins(1,4,5)P3 formation were also changed by prolonged treatment with 8Br-cAMP to a monophasic response in which Ins(1,4,5)P3 increased rapidly and remained elevated during All stimulation. In permeabilized glomerulosa cells treated with 8Br-cAMP for 16 h, the conversion of D-myo-inositol 1,3,4-trisphosphate [Ins(1,3,4)P3] to Ins(1,3,4,6)P4 was consistently increased, whereas dephosphorylation of Ins(1,4,5)P3 to D-myo-inositol 1,4-bisphosphate and of D-myo-inositol 1,3,4,5-tetrakisphosphate to Ins(1,3,4)P3, was reduced

Analysis of the spectrum six times ionized zinc (Zn VII): the 3d6-3d54p transition array

International Nuclear Information System (INIS)

Hof, G.H. van het; Joshi, Y.N.; Raassen, A.J.J.; Ryabtsev, A.N.

1993-01-01

The spectrum of zinc was photographed in the 100-300 A region on a 10.7 m grazing incidence spectrograph using a triggered spark light source. 335 lines were classified in the Zn VII 3d 6 -3d 5 4p transition array, resulting in the establishment of 30 of the 34 levels of the 3d 6 configuration and 103 of the 214 levels of the 3d 5 4p. The ground configuration 3d 6 was described by a generalized least-squares fit (GLSF) involving orthogonal operators to a set of 3d N configurations. This yielded a mean error of 3 cm -1 for its level values. The excited configruation was described by the conventional Slater Condon parameter set, giving a mean error of 105 cm -1 . (orig.)

Purification and investigation of some kinetic properties of glucose-6-phosphate dehydrogenase from parsley (Petroselinum hortense) leaves.

Science.gov (United States)

Coban, T Abdül Kadir; Ciftçi, Mehmet; Küfrevioğlu, O Irfan

2002-05-01

In this study, glucose-6-phosphate dehydrogenase (D-glucose-6-phosphate: NADP+ oxidoreductase, EC 1.1.1.49; G6PD) was purified from parsley (Petroselinum hortense) leaves, and analysis of the kinetic behavior and some properties of the enzyme were investigated. The purification consisted of three steps: preparation of homogenate, ammonium sulfate fractionation, and DEAE-Sephadex A50 ion exchange chromatography. The enzyme was obtained with a yield of 8.79% and had a specific activity of 2.146 U (mg protein)(-1). The overall purification was about 58-fold. Temperature of +4 degrees C was maintained during the purification process. Enzyme activity was spectrophotometrically measured according to the Beutler method, at 340 nm. In order to control the purification of enzyme, SDS-polyacrylamide gel electrophoresis was carried out in 4% and 10% acrylamide for stacking and running gel, respectively. SDS-polyacrylamide gel electrophoresis showed a single band for enzyme. The molecular weight was found to be 77.6 kDa by Sephadex G-150 gel filtration chromatography. A protein band corresponding to a molecular weight of 79.3 kDa was obtained on SDS-polyacrylamide gel electrophoresis. For the enzymes, the stable pH, optimum pH, and optimum temperature were found to be 6.0, 8.0, and 60 degrees C, respectively. Moreover, KM and Vmax values for NADP+ and G6-P at optimum pH and 25 degrees C were determined by means of Lineweaver-Burk graphs. Additionally, effects of streptomycin sulfate and tetracycline antibiotics were investigated for the enzyme activity of glucose-6-phosphate dehydrogenase in vitro.

Prevalence of glucose-6-phosphate dehydrogenase deficiency in ...

African Journals Online (AJOL)

Background: Glucose-6-phosphate dehydrogenase (G6PD) is a house keeping enzyme which catalyzes the first step in the hexose monophosphate pathway of glucose metabolism. G6PD deficiency is the commonest hemolytic X-linked genetic disease, which affects approximately 400 million people worldwide.

Inhibition of the pentose phosphate shunt by 2,3-diphosphoglycerate in erythrocyte pyruvate kinase deficiency.

Science.gov (United States)

Tomoda, A; Lachant, N A; Noble, N A; Tanaka, K R

1983-07-01

Pentose phosphate shunt activity was studied by the release of 14CO2 from 14C-1-glucose and 14C-2-glucose in the red cells of five patients with pyruvate kinase deficiency and found to be significantly decreased after new methylene blue stimulation when compared to high reticulocyte controls. Incubated Heinz body formation was increased and the ascorbate cyanide test was positive in blood from these patients. The activity of glucose-6-phosphate dehydrogenase (G6PD) as well as that of 6-phosphogluconate dehydrogenase (6PGD) was inhibited to 20% of baseline in normal red cell haemolysate by 4 mM 2,3-diphosphoglycerate at pH 7.1. 2,3-Diphosphoglycerate was a competitive inhibitor with 6-phosphogluconate (Ki=1.05 mM) and a noncompetitive inhibitor with NADP (Ki=3.3 mM) for 6PGD. Since the intracellular concentrations of glucose-6-phosphate, 6-phosphogluconate and NADP are below their Kms for G6PD and 6PGD, the kinetic data suggest that increased concentrations of 2,3-diphosphoglycerate in pyruvate kinase deficient red cells are sufficiently high to suppress pentose phosphate shunt activity. This suppression may be an additional factor contributing to the haemolytic anaemia of pyruvate kinase deficiency, particularly during periods of infection or metabolic stress.

Weighted f-values, A-values, and line strengths for the E1 transitions among 3d6, 3d54s, and 3d54p levels of Fe III

International Nuclear Information System (INIS)

Deb, Narayan C.; Hibbert, Alan

2009-01-01

Weighted oscillator strengths, weighted radiative rates, and line strengths for all the E1 transitions between 285 fine-structure levels belonging to the 3d 6 , 3d 5 4s, and 3d 5 4p configurations of Fe III are presented, in ascending order of wavelength. Calculations have been undertaken using the general configuration interaction (CI) code CIV3. The large configuration set is constructed by allowing single and double replacements from any of 3d 6 , 3d 5 4s, 3d 5 4p, and 3d 5 4d configurations to nl orbitals with n≤5,l≤3 as well as 6p. Additional selective promotions from 3s and 3p subshells are also included in the CI expansions to incorporate the important correlation effects in the n=3 shell. Results of some strong transitions between levels of 3d 6 , 3d 5 4s, and 3d 5 4p configurations are also presented and compared with other available calculations. It is found that large disagreements occur in many transitions among the existing calculations

Data for analysis of mannose-6-phosphate glycans labeled with fluorescent tags.

Science.gov (United States)

Kang, Ji-Yeon; Kwon, Ohsuk; Gil, Jin Young; Oh, Doo-Byoung

2016-06-01

Mannose-6-phosphate (M-6-P) glycan plays an important role in lysosomal targeting of most therapeutic enzymes for treatment of lysosomal storage diseases. This article provides data for the analysis of M-6-P glycans by high-performance liquid chromatography (HPLC) and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. The identities of M-6-P glycan peaks in HPLC profile were confirmed by measuring the masses of the collected peak eluates. The performances of three fluorescent tags (2-aminobenzoic acid [2-AA], 2-aminobenzamide [2-AB], and 3-(acetyl-amino)-6-aminoacridine [AA-Ac]) were compared focusing on the analysis of bi-phosphorylated glycan (containing two M-6-Ps). The bi-phosphorylated glycan analysis is highly affected by the attached fluorescent tag and the hydrophilicity of elution solvent used in HPLC. The data in this article is associated with the research article published in "Comparison of fluorescent tags for analysis of mannose-6-phosphate glycans" (Kang et al., 2016 [1]).

Comparison of Anti-Obesity Effect between Two Types of Syrup Containing Rare Sugars in Wistar Rats.

Science.gov (United States)

Ochiai, Masaru; Misaki, Kohei; Yamada, Takako; Iida, Tetsuo; Okuma, Kazuhiro; Matsuo, Tatsuhiro

2017-01-01

D-Allulose-containing rare sugar sweeteners have been categorized into two types, rare sugar syrup (RSS), consisting of 4 rare monosaccharides, and modified glucose syrup (MGS), rich in D-allulose, which was previously referred to D-psicose. The anti-obesity effect of RSS and D-allulose has been already clarified, but that of rare monosaccharides other than D-allulose in RSS has not yet been well understood. Here, we investigated and compared the anti-obesity effect of RSS and MGS in rats. Male Wistar rats were divided into 4 dietary groups: a high-sucrose control diet group (S), a high-fructose corn syrup diet group (HFCS), an RSS diet group (RSS), and an MGS diet group (MGS). RSS significantly suppressed abdominal adipose tissue weight and total body fat accumulation in comparison to sucrose. On the other hand, MGS reduced body weight gain, but not abdominal fat accumulation, relative to sucrose. The weight of the liver and kidneys was significantly higher in the RSS and MGS groups than in the S and HFCS groups, but serum biochemical parameters and hepatic lipids contents were not significantly different among the groups. The present study shows that two types of D-allulose-containing rare sugar sweeteners can suppress body fat accumulation or weight gain in a different manner and that RSS could be used as more effective sweeteners in place of sucrose and HFCS to maintain healthy body weight.

Metabolic engineering of Corynebacterium glutamicum to produce GDP-L-fucose from glucose and mannose.

Science.gov (United States)

Chin, Young-Wook; Park, Jin-Byung; Park, Yong-Cheol; Kim, Kyoung Heon; Seo, Jin-Ho

2013-06-01

Wild-type Corynebacterium glutamicum was metabolically engineered to convert glucose and mannose into guanosine 5'-diphosphate (GDP)-L-fucose, a precursor of fucosyl-oligosaccharides, which are involved in various biological and pathological functions. This was done by introducing the gmd and wcaG genes of Escherichia coli encoding GDP-D-mannose-4,6-dehydratase and GDP-4-keto-6-deoxy-D-mannose-3,5-epimerase-4-reductase, respectively, which are known as key enzymes in the production of GDP-L-fucose from GDP-D-mannose. Coexpression of the genes allowed the recombinant C. glutamicum cells to produce GDP-L-fucose in a minimal medium containing glucose and mannose as carbon sources. The specific product formation rate was much higher during growth on mannose than on glucose. In addition, the specific product formation rate was further increased by coexpressing the endogenous phosphomanno-mutase gene (manB) and GTP-mannose-1-phosphate guanylyl-transferase gene (manC), which are involved in the conversion of mannose-6-phosphate into GDP-D-mannose. However, the overexpression of manA encoding mannose-6-phosphate isomerase, catalyzing interconversion of mannose-6-phosphate and fructose-6-phosphate showed a negative effect on formation of the target product. Overall, coexpression of gmd, wcaG, manB and manC in C. glutamicum enabled production of GDP-L-fucose at the specific rate of 0.11 mg g cell(-1) h(-1). The specific GDP-L-fucose content reached 5.5 mg g cell(-1), which is a 2.4-fold higher than that of the recombinant E. coli overexpressing gmd, wcaG, manB and manC under comparable conditions. Well-established metabolic engineering tools may permit optimization of the carbon and cofactor metabolisms of C. glutamicum to further improve their production capacity.

Efficient regeneration of NADPH in a 3-enzyme cascade reaction by in situ generation of glucose 6-phosphate from glucose and pyrophosphate

NARCIS (Netherlands)

Hartog, A.F.; van Herk, T.; Wever, R.

2011-01-01

We report here a promising method to regenerate NADPH (nicotinamide adenine dinucleotide phosphate) using the intermediate formation of glucose 6-phosphate (G6P) from glucose and pyrophosphate (PPi) catalyzed by the acid phosphatase from Shigella flexneri (PhoN-Sf). The G6P formed is used in turn by

Synthesis of 6-O-(5-acetamido-3,5-dideoxy-α-D-glycero-D-galacto-2-nonulopyranosylonic acid)-D-galactose [6-O-(N-acetyl-α-D-neuraminyl)-D-galactose

NARCIS (Netherlands)

Vliegenthart, J.F.G.; Vleugel, D.J.M. van der; Wassenburg, F.R.; Zwikker, J.W.

1982-01-01

Condensation of methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-2-chloro-2,3,5-trideoxy-beta-D-glycero-D-galacto-2-nonulopyranosonate with benzyl 2,3,4-tri-O-benzyl-beta-D-galactopyranoside, using silver salicylate as promoter, gave benzyl 2,3,4-tri-O-benzyl-6-O-(methyl

Overexpression, crystallization and preliminary X-ray analysis of xylulose-5-phosphate/fructose-6-phosphate phosphoketolase from Bifidobacterium breve

International Nuclear Information System (INIS)

Suzuki, Ryuichiro; Kim, Byung-Jun; Shibata, Tsuyoshi; Iwamoto, Yuki; Katayama, Takane; Ashida, Hisashi; Wakagi, Takayoshi; Shoun, Hirofumi; Fushinobu, Shinya; Yamamoto, Kenji

2010-01-01

Xylulose-5-phosphate/fructose-6-phosphate phosphoketolase from B. breve was overexpressed and crystallized. The crystals belonged to the tetragonal space group I422 and diffracted to beyond 1.7 Å resolution. The xylulose-5-phosphate/fructose-6-phosphate phosphoketolase gene from Bifidobacterium breve was cloned and overexpressed in Escherichia coli. The enzyme was purified to homogeneity and crystallized by the sitting-drop vapour-diffusion method. Crystals were obtained at 293 K using 0.05 mM thiamine diphosphate, 0.25 mM MgCl 2 , 24%(w/v) PEG 6000 and 0.1 M Bicine pH 9.0. The crystals belonged to the tetragonal space group I422, with unit-cell parameters a = b = 174.8, c = 163.8 Å, and diffracted to beyond 1.7 Å resolution

Glucose 6 phosphate dehydrogenase deficiency in adults

International Nuclear Information System (INIS)

Khan, M.

2004-01-01

Objective: To determine the frequency of glucose-6-phosphate dehydrogenase (G6PD) deficiency in adults presented with anemia. Subjects and Methods: Eighteen months admission data was reviewed for G6PD deficiency as a cause of anemia. Anemia was defined by world health organization (WHO) criteria as haemoglobin less than 11.3 gm%. G6PD activity was measured by Sigma dye decolorisation method. All patients were screened for complications of hemolysis and its possible cause. Patients with more than 13 years of age were included in the study. Results: Out of 3600 patients admitted, 1440 were found anaemic and 49 as G6PD deficient. So the frequency of G6PD deficiency in anaemic patients was 3.4% and the overall frequency is 1.36%. G6PD deficiency among males and females was three and six percent respectively. Antimalarials and antibiotics containing sulphonamide group were the most common precipitating factors for hemolysis. Anemia and jaundice were the most common presentations while malaria was the most common associated disease. Acute renal failure was the most severe complication occurring in five patients with two deaths. Conclusion: G6PD deficiency is a fairly common cause of anemia with medicine as common precipitating factor for hemolysis. Such complications can be avoided with early recognition of the disease and avoiding indiscriminate use of medicine. (author)

A study of luminescence from Eu"3"+, Ce"3"+, Tb"3"+ and Ce"3"+/Tb"3"+ in new potassium gadolinium phosphate K_3Gd_5(PO_4)_6

International Nuclear Information System (INIS)

Meng, Fangui; Zhang, Hongzhi; Chen, Cuili; Kim, Sun Il; Seo, Hyo Jin; Zhang, Xinmin

2016-01-01

New potassium gadolinium phosphate [K_3Gd_5(PO_4)_6] doped with Eu"3"+, Ce"3"+, Tb"3"+ and co-doped with Ce"3"+ and Tb"3"+ phosphors were prepared by high temperature solid state synthesis. Phase purity of the powders was checked by X-ray powder diffraction. Luminescence and excitation spectra of samples were reported. In particular, the interaction mechanism between Eu"3"+ ions was investigated in terms of the Inokuti–Hirayama model; it was found that the interactions between Eu"3"+ can be assigned to dipole–dipole interaction. K_3Gd_5(PO_4)_6:Eu"3"+ could act as a candidate for solid state lighting due to its strong absorption band in the near-UV region (350–400 nm). The energy transfer from Ce"3"+ to Tb"3"+ was confirmed and the mechanism was studied using Dexter's theory; it is concluded that electric dipole–dipole interaction predominates in the energy transfer process from Ce"3"+ to Tb"3"+ in the K_3Gd_5(PO_4)_6 host. The energy transfer efficiency and critical distance were also investigated. - Highlights: • Optical properties of K_3Gd_5(PO_4)_6:RE"3"+ are investigated for the first time. • The interaction mechanism between Eu"3"+ ions is attributed to dipole–dipole type. • K_3Eu_5(PO_4)_6 is a candidate phosphor for application to solid state lighting. • There exists an efficient energy transfer from Ce"3"+ to Tb"3"+ (η is up to 95%). • The mechanism of energy transfer process is electric dipole–dipole interaction.

UDP-galactose 4'-epimerase activities toward UDP-Gal and UDP-GalNAc play different roles in the development of Drosophila melanogaster.

Directory of Open Access Journals (Sweden)

Jennifer M I Daenzer

Full Text Available In both humans and Drosophila melanogaster, UDP-galactose 4'-epimerase (GALE catalyzes two distinct reactions, interconverting UDP-galactose (UDP-gal and UDP-glucose (UDP-glc in the final step of the Leloir pathway of galactose metabolism, and also interconverting UDP-N-acetylgalactosamine (UDP-galNAc and UDP-N-acetylglucosamine (UDP-glcNAc. All four of these UDP-sugars serve as vital substrates for glycosylation in metazoans. Partial loss of GALE in humans results in the spectrum disorder epimerase deficiency galactosemia; partial loss of GALE in Drosophila melanogaster also results in galactose-sensitivity, and complete loss in Drosophila is embryonic lethal. However, whether these outcomes in both humans and flies result from loss of one GALE activity, the other, or both has remained unknown. To address this question, we uncoupled the two activities in a Drosophila model, effectively replacing the endogenous dGALE with prokaryotic transgenes, one of which (Escherichia coli GALE efficiently interconverts only UDP-gal/UDP-glc, and the other of which (Plesiomonas shigelloides wbgU efficiently interconverts only UDP-galNAc/UDP-glcNAc. Our results demonstrate that both UDP-gal and UDP-galNAc activities of dGALE are required for Drosophila survival, although distinct roles for each activity can be seen in specific windows of developmental time or in response to a galactose challenge. By extension, these data also suggest that both activities might play distinct and essential roles in humans.

Glucose-6-phosphate reduces calcium accumulation in rat brain endoplasmic reticulum

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Jeffrey Thomas Cole

2012-04-01

Full Text Available Brain cells expend large amounts of energy sequestering calcium (Ca2+, while loss of Ca2+ compartmentalization leads to cell damage or death. Upon cell entry, glucose is converted to glucose-6-phosphate (G6P, a parent substrate to several metabolic major pathways, including glycolysis. In several tissues, G6P alters the ability of the endoplasmic reticulum to sequester Ca2+. This led to the hypothesis that G6P regulates Ca2+ accumulation by acting as an endogenous ligand for sarco-endoplasmic reticulum calcium ATPase (SERCA. Whole brain ER microsomes were pooled from adult male Sprague-Dawley rats. Using radio-isotopic assays, 45Ca2+ accumulation was quantified following incubation with increasing amounts of G6P, in the presence or absence of thapsigargin, a potent SERCA inhibitor. To qualitatively assess SERCA activity, the simultaneous release of inorganic phosphate (Pi coupled with Ca2+ accumulation was quantified. Addition of G6P significantly and decreased Ca2+ accumulation in a dose-dependent fashion (1-10 mM. The reduction in Ca2+ accumulation was not significantly different that seen with addition of thapsigargin. Addition of glucose-1-phosphate or fructose-6-phosphate, or other glucose metabolic pathway intermediates, had no effect on Ca2+ accumulation. Further, the release of Pi was markedly decreased, indicating G6P-mediated SERCA inhibition as the responsible mechanism for reduced Ca2+ uptake. Simultaneous addition of thapsigargin and G6P did decrease inorganic phosphate in comparison to either treatment alone, which suggests that the two treatments have different mechanisms of action. Therefore, G6P may be a novel, endogenous regulator of SERCA activity. Additionally, pathological conditions observed during disease states that disrupt glucose homeostasis, may be attributable to Ca2+ dystasis caused by altered G6P regulation of SERCA activity

Identification of glucose 6 phosphate dehydrogenase mutations by ...

African Journals Online (AJOL)

Identification of glucose 6 phosphate dehydrogenase mutations by single strand conformation polymorphism and gene sequencing analysis. ... Subject: Six DNA samples from Turkish males confirmed to have G-6-PD deficiency where available for the study. Results: One subject was found to have an abnormal mobility shift ...

Oral antibodies to human intestinal alkaline phosphatase reduce dietary phytate phosphate bioavailability in the presence of dietary 1α-hydroxycholecalciferol.

Science.gov (United States)

Bobeck, Elizabeth A; Hellestad, Erica M; Helvig, Christian F; Petkovich, P Martin; Cook, Mark E

2016-03-01

While it is well established that active vitamin D treatment increases dietary phytate phosphate utilization, the mechanism by which intestinal alkaline phosphatase (IAP) participates in phytate phosphate use is less clear. The ability of human IAP (hIAP) oral antibodies to prevent dietary phytate phosphate utilization in the presence of 1α-hydroxycholecalciferol (1α-(OH) D3) in a chick model was investigated. hIAP specific chicken immunoglobulin Y (IgY) antibodies were generated by inoculating laying hens with 17 synthetic peptides derived from the human IAP amino acid sequence and harvesting egg yolk. Western blot analysis showed all antibodies recognized hIAP and 6 of the 8 antibodies selected showed modest inhibition of hIAP activity in vitro (6 to 33% inhibition). In chicks where dietary phosphate was primarily in the form of phytate, 4 selected hIAP antibodies inhibited 1α-(OH) D3-induced increases in blood phosphate, one of which, generated against selected peptide (MFPMGTPD), was as effective as sevelamer hydrochloride in preventing the 1α-(OH) D3-induced increase in blood phosphate, but ineffective in preventing an increase in body weight gain and bone ash induced by 1α-(OH) D3. These studies demonstrated that orally-delivered antibodies to IAP limit dietary phytate-phosphate utilization in chicks treated with 1α-(OH) D3, and implicate IAP as an important host enzyme in increasing phytate phosphate bioavailability in 1α-(OH) D3 fed chicks. © 2015 Poultry Science Association Inc.

Activation of PLC by an endogenous cytokine (GBP) in Drosophila S3 cells and its application as a model for studying inositol phosphate signalling through ITPK1.

Science.gov (United States)

Zhou, Yixing; Wu, Shilan; Wang, Huanchen; Hayakawa, Yoichi; Bird, Gary S; Shears, Stephen B

2012-12-01

Using immortalized [3H]inositol-labelled S3 cells, we demonstrated in the present study that various elements of the inositol phosphate signalling cascade are recruited by a Drosophila homologue from a cytokine family of so-called GBPs (growth-blocking peptides). HPLC analysis revealed that dGBP (Drosophila GBP) elevated Ins(1,4,5)P3 levels 9-fold. By using fluorescent Ca2+ probes, we determined that dGBP initially mobilized Ca2+ from intracellular pools; the ensuing depletion of intracellular Ca2+ stores by dGBP subsequently activated a Ca2+ entry pathway. The addition of dsRNA (double-stranded RNA) to knock down expression of the Drosophila Ins(1,4,5)P3 receptor almost completely eliminated mobilization of intracellular Ca2+ stores by dGBP. Taken together, the results of the present study describe a classical activation of PLC (phospholipase C) by dGBP. The peptide also promoted increases in the levels of other inositol phosphates with signalling credentials: Ins(1,3,4,5)P4, Ins(1,4,5,6)P4 and Ins(1,3,4,5,6)P5. These results greatly expand the regulatory repertoire of the dGBP family, and also characterize S3 cells as a model for studying the regulation of inositol phosphate metabolism and signalling by endogenous cell-surface receptors. We therefore created a cell-line (S3ITPK1) in which heterologous expression of human ITPK (inositol tetrakisphosphate kinase) was controlled by an inducible metallothionein promoter. We found that dGBP-stimulated S3ITPK1 cells did not synthesize Ins(3,4,5,6)P4, contradicting a hypothesis that the PLC-coupled phosphotransferase activity of ITPK1 [Ins(1,3,4,5,6)P5+Ins(1,3,4)P3→Ins(3,4,5,6)P4+Ins(1,3,4,6)P4] is driven solely by the laws of mass action [Chamberlain, Qian, Stiles, Cho, Jones, Lesley, Grabau, Shears and Spraggon (2007) J. Biol. Chem. 282, 28117-28125]. This conclusion represents a fundamental breach in our understanding of ITPK1 signalling.

Data for analysis of mannose-6-phosphate glycans labeled with fluorescent tags

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Ji-Yeon Kang

2016-06-01

Full Text Available Mannose-6-phosphate (M-6-P glycan plays an important role in lysosomal targeting of most therapeutic enzymes for treatment of lysosomal storage diseases. This article provides data for the analysis of M-6-P glycans by high-performance liquid chromatography (HPLC and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF mass spectrometry. The identities of M-6-P glycan peaks in HPLC profile were confirmed by measuring the masses of the collected peak eluates. The performances of three fluorescent tags (2-aminobenzoic acid [2-AA], 2-aminobenzamide [2-AB], and 3-(acetyl-amino-6-aminoacridine [AA-Ac] were compared focusing on the analysis of bi-phosphorylated glycan (containing two M-6-Ps. The bi-phosphorylated glycan analysis is highly affected by the attached fluorescent tag and the hydrophilicity of elution solvent used in HPLC. The data in this article is associated with the research article published in “Comparison of fluorescent tags for analysis of mannose-6-phosphate glycans” (Kang et al., 2016 [1].

Glucose-6-phosphate dehydrogenase deficiency; the single most ...

African Journals Online (AJOL)

Introduction: Glucose- 6-phosphate dehydrogenase deficiency is the most common enzymatic disorder of the red cell and an important risk factor for neonatal jaundice. Methodology: The aim of the study was to determine the incidence of G-6-PD deficiency among jaundiced neonates, and describe the associated morbidity ...

Glucose-6-phosphate dehydrogenase protects Escherichia coli from tellurite-mediated oxidative stress.

Directory of Open Access Journals (Sweden)

Juan M Sandoval

Full Text Available The tellurium oxyanion tellurite induces oxidative stress in most microorganisms. In Escherichia coli, tellurite exposure results in high levels of oxidized proteins and membrane lipid peroxides, inactivation of oxidation-sensitive enzymes and reduced glutathione content. In this work, we show that tellurite-exposed E. coli exhibits transcriptional activation of the zwf gene, encoding glucose 6-phosphate dehydrogenase (G6PDH, which in turn results in augmented synthesis of reduced nicotinamide adenine dinucleotide phosphate (NADPH. Increased zwf transcription under tellurite stress results mainly from reactive oxygen species (ROS generation and not from a depletion of cellular glutathione. In addition, the observed increase of G6PDH activity was paralleled by accumulation of glucose-6-phosphate (G6P, suggesting a metabolic flux shift toward the pentose phosphate shunt. Upon zwf overexpression, bacterial cells also show increased levels of antioxidant molecules (NADPH, GSH, better-protected oxidation-sensitive enzymes and decreased amounts of oxidized proteins and membrane lipids. These results suggest that by increasing NADPH content, G6PDH plays an important role in E. coli survival under tellurite stress.

Glucose-6-phosphate dehydrogenase deficiency in Singapore.

Science.gov (United States)

Quak, S H; Saha, N; Tay, J S

1996-01-01

Glucose-6-phosphate dehydrogenase (G6PD) in man is an X-linked enzyme. The deficiency of this enzyme is one of the most common inherited metabolic disorders in man. In Singapore, three clinical syndromes associated with G6PD deficiency had been described: severe haemolysis in neonates with kernicterus, haemoglobinuria and "viral hepatitis"-like syndrome. The human G6PD monomer consists of 515 amino acids. Only the tetrameric or dimeric forms composed of a single type subunit are catylitically active. The complete amino acid sequence of G6PD had been elucidated in man and various other animals. The region of high homology among the enzymes of various animals is presumably functionally active. Among the Chinese in Singapore, three common molecular variants had been identified: Canton (nt 1376 G --> T), Kaiping (nt 1388 G --> A) and Mediterranean (nt 563 C --> T) in frequencies of 24%, 21% and 10% respectively. In addition, two common mutants (Gaozhou, nt 95 A --> G and Chinese 5, nt 1024 C --> T) have been detected in Singapore Chinese in low frequencies. In Malays, 6 different deficient variants are known in Singapore (3 new, 1 Mahidol, 1 Indonesian and 1 Mediterranean).

Down-shifting by energy transfer in Tb{sup 3+}/Dy{sup 3+} co-doped zinc phosphate glasses

Energy Technology Data Exchange (ETDEWEB)

Caldiño, U., E-mail: cald@xanum.uam.mx [Departamento de Física, Universidad Autónoma Metropolitana-Iztapalapa, P.O. Box 55-534, México, D.F. 09340 (Mexico); Muñoz H, G.; Camarillo, I. [Departamento de Física, Universidad Autónoma Metropolitana-Iztapalapa, P.O. Box 55-534, México, D.F. 09340 (Mexico); Speghini, A. [Dipartimento di Biotecnologie, Università di Verona, and INSTM, UdR Verona, Strada Le Grazie 15, I-37314 Verona (Italy); IFAC CNR, Nello Carrara Institute of Applied Physics, MDF Lab, I-50019 Sesto Fiorentino, FI (Italy); Bettinelli, M. [Dipartimento di Biotecnologie, Università di Verona, and INSTM, UdR Verona, Strada Le Grazie 15, I-37314 Verona (Italy)

2015-05-15

An optical spectroscopy investigation of zinc phosphate glasses activated with Tb{sup 3+}/Dy{sup 3+} ions is carried out through photoluminescence spectra and decay time measurements. The emission color can be adjusted from yellow–green light, with CIE1931 chromaticity coordinates (0.36,0.44), toward the white light region (0.35,0.39) by decreasing the Tb{sup 3+} content from 1.0 to 0.1 mol% of Tb(PO{sub 3}){sub 3} upon Dy{sup 3+} excitation at 423 nm. Such visible region luminescence is generated by {sup 5}D{sub 4}→{sup 7}F{sub 5} and {sup 5}D{sub 4}→{sup 7}F{sub 3} emissions of Tb{sup 3+} in addition to {sup 4}I{sub 15/2}→{sup 6}H{sub 15/2}, {sup 4}F{sub 9/2}→{sup 6}H{sub 15/2}, {sup 4}F{sub 9/2}→{sup 6}H{sub 13/2} and {sup 4}F{sub 9/2}→{sup 6}H{sub 11/2} emissions of Dy{sup 3+}, so that Tb{sup 3+} emission is sensitized by Dy{sup 3+} through a non-radiative resonant energy transfer. A dominant {sup 5}D{sub 4}→{sup 7}F{sub 5} green emission is observed in detriment of the {sup 5}D{sub 3}→{sup 7}F{sub J} blue emissions upon 282 nm excitation, as well as an extended excitation range (280–500 nm), due to multiple Dy{sup 3+} and Tb{sup 3+} transitions, which might contribute to enhance the spectral response of solar photovoltaic cells by down-shifting of the incident solar spectrum. - Highlights: • Zn(PO{sub 3}){sub 2} glasses are optically activated with Tb{sup 3+}/Dy{sup 3+} (ZPTbDy). • Non-radiative resonant energy transfer takes place between Tb{sup 3+} and Dy{sup 3+}. • Luminescence can be adjusted from yellow–green light toward the white light region. • ZPTbDy phosphor exhibits spectroscopic properties for photovoltaic applications.

Tetranuclear copper(II) complexes bridged by alpha-D-glucose-1-phosphate and incorporation of sugar acids through the Cu4 core structural changes.

Science.gov (United States)

Kato, Merii; Sah, Ajay Kumar; Tanase, Tomoaki; Mikuriya, Masahiro

2006-08-21

Tetranuclear copper(II) complexes containing alpha-D-glucose-1-phosphate (alpha-D-Glc-1P), [Cu4(mu-OH){mu-(alpha-D-Glc-1P)}2(bpy)4(H2O)2]X3 [X = NO3 (1a), Cl (1b), Br (1c)], and [Cu4(mu-OH){mu-(alpha-D-Glc-1P)}2(phen)4(H2O)2](NO3)3 (2) were prepared by reacting the copper(II) salt with Na2[alpha-D-Glc-1P] in the presence of diimine ancillary ligands, and the structure of 2 was characterized by X-ray crystallography to comprise four {Cu(phen)}2+ fragments connected by the two sugar phosphate dianions in 1,3-O,O' and 1,1-O mu4-bridging fashion as well as a mu-hydroxo anion. The crystal structure of 2 involves two chemically independent complex cations in which the C2 enantiomeric structure for the trapezoidal tetracopper(II) framework is switched according to the orientation of the alpha-D-glucopyranosyl moieties. Temperature-dependent magnetic susceptibility data of 1a indicated that antiferromagnetic spin coupling is operative between the two metal ions joined by the hydroxo bridge (J = -52 cm(-1)) while antiferromagnetic interaction through the Cu-O-Cu sugar phosphate bridges is weak (J = -13 cm(-1)). Complex 1a readily reacted with carboxylic acids to afford the tetranuclear copper(II) complexes, [Cu4{mu-(alpha-D-Glc-1P)}2(mu-CA)2(bpy)4](NO3)2 [CA = CH3COO (3), o-C6H4(COO)(COOH) (4)]. Reactions with m-phenylenediacetic acid [m-C6H4(CH2COOH)2] also gave the discrete tetracopper(II) cationic complex [Cu4{mu-(alpha-D-Glc-1P)}2(mu-m-C6H4(CH2COO)(CH2COOH))2(bpy)4](NO3)2 (5a) as well as the cluster polymer formulated as {[Cu4{mu-(alpha-D-Glc-1P)}2(mu-m-C6H4(CH2COO)2)(bpy)4](NO3)2}n (5b). The tetracopper structure of 1a is converted into a symmetrical rectangular core in complexes 3, 4, and 5b, where the hydroxo bridge is dissociated and, instead, two carboxylate anions bridge another pair of Cu(II) ions in a 1,1-O monodentate fashion. The similar reactions were applied to incorporate sugar acids onto the tetranuclear copper(II) centers. Reactions of 1a with delta-D

Phosphate attenuates the anti-proteinuric effect of very low-protein diet in CKD patients.

Science.gov (United States)

Di Iorio, Biagio R; Bellizzi, Vincenzo; Bellasi, Antonio; Torraca, Serena; D'Arrigo, Graziella; Tripepi, Giovanni; Zoccali, Carmine

2013-03-01

High phosphate levels attenuate nephroprotection through angiotensin-converting enzyme inhibition in patients with proteinuric chronic kidney disease (CKD). Whether this phenomenon holds true for other nephroprotective interventions like very-low-protein diet (VLPD) is unknown. We tested the hypothesis that phosphate interferes with the anti-proteinuric response to VLPD in a non-randomized, sequential study in 99 proteinuric CKD patients who sequentially underwent low-protein diet (LPD; 0.6 g/kg) and VLPD (0.3 g/kg) supplemented with keto-analogues, each for periods longer than 1 year. Serum phosphate significantly reduced during VLPD (3.2 ± 0.6 mg/dL) when compared with LPD (3.7 ± 0.6 mg/dL, P diet periods. In linear mixed models including the diagnosis of renal disease, eGFR, 24-h urine sodium and urea and other potential confounders, there was a strong interaction between serum phosphate (P = 0.04) and phosphaturia (P < 0.001) with the anti-proteinuric response to VLPD. Accordingly, 24-h proteinuria reduced modestly in patients who maintained relatively higher serum phosphate levels or relatively higher phosphaturia to be maximal in those who achieved the lowest level of serum and urine phosphate. Phosphate is an important modifier of the anti-proteinuric response to VLPD. Reducing phosphate burden may decrease proteinuria and slow the progression of renal disease in CKD patients, an issue that remains to be tested in specific clinical trials.

GATA4-mediated cardiac hypertrophy induced by D-myo-inositol 1,4,5-tris-phosphate

International Nuclear Information System (INIS)

Zhu Zhiming; Zhu Shanjun; Liu Daoyan; Yu Zengping; Yang Yongjian; Giet, Markus van der; Tepel, Martin

2005-01-01

We evaluated the effects of D-myo-inositol 1,4,5-tris-phosphate on cardiac hypertrophy. D-myo-inositol 1,4,5-tris-phosphate augmented cardiac hypertrophy as evidenced by its effects on DNA synthesis, protein synthesis, and expression of immediate-early genes c-myc and c-fos, β-myosin heavy chain, and α-actin. The administration of D-myo-inositol 1,4,5-tris-phosphate increased the expression of nuclear factor of activated T-cells and cardiac-restricted zinc finger transcription factor (GATA4). Real-time quantitative RT-PCR showed that D-myo-inositol 1,4,5-tris-phosphate-induced GATA4 mRNA was significantly enhanced even in the presence of the calcineurin inhibitor, cyclosporine A. The effect of D-myo-inositol 1,4,5-tris-phosphate was blocked after inhibition of inositol-trisphosphate receptors but not after inhibition of c-Raf/mitogen-activated protein kinase kinase (MEK)/mitogen-activated protein kinase (ERK) or p38 mitogen-activated protein kinase pathways. The study shows that D-myo-inositol 1,4,5-tris-phosphate-induced cardiac hypertrophy is mediated by GATA4 but independent from the calcineurin pathway

Electron collisions with Fe-peak elements: Forbidden transitions between the low lying valence states 3d6, 3d54s, and 3d54p of Fe III

International Nuclear Information System (INIS)

McLaughlin, B.M.; Scott, M.P.; Sunderland, A.G.; Noble, C.J.; Burke, V.M.; Ramsbottom, C.A.; Reid, R.H.G.; Hibbert, A.; Bell, K.L.; Burke, P.G.

2007-01-01

Effective collision strengths are presented for the Fe-peak element Fe III at electron temperatures (T e in degrees Kelvin) in the range 2 x 10 3 to 1 x 10 6 . Forbidden transitions results are given between the 3d 6 , 3d 5 4s, and the 3d 5 4p manifolds applicable to the modeling of laboratory and astrophysical plasmas

Contribution to the study of uranyl salts in butyl phosphate solutions; Contribution a l'etude des solutions de sels d'uranyle dans les phosphates butyliques

Energy Technology Data Exchange (ETDEWEB)

Coulon, A [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

1965-06-01

A spectroscopic study in the normal infrared region and involving the following associations: tri-alkyl phosphates (tri-butyl, tri-ethyl, tri-methyl), uranyl salts (nitrate, chloride, acetate) has confirmed the existence of an interaction between the phosphoryl group and the uranium atom, as shown by a movement of absorption band for the valency P = 0 from {approx} 1270 cm{sup -1} to {approx} 1180 cm{sup -1}. A study of the preparation, analysis and spectroscopy of the solids obtained by the precipitation of uranyl salts by acid butyl phosphates has been carried out. By infrared spectrophotometry it has been shown that the tri-butyl and di-butyl phosphates are associated in non-polar diluents even before the uranium is introduced. The extraction of uranyl salts from acid aqueous solutions by a diluted mixture of tri-butyl and di-butyl phosphates proceeds by different mechanisms according to the nature of the ion (nitrate or chloride). (author) [French] Une etude spectroscopique dans l'infrarouge moyen portant sur les associations: - phosphates trialcoyliques (tributylique - triethylique - trimethylique) - sels d'uranyle (nitrate, chlorure, acetate) a confirme l'existence d'une interaction entre le groupement phosphoryle et l'atome d'uranium, se manifestant par un deplacement de la bande d'absorption de la vibration de valence P = 0 de {approx} 1270 cm{sup -1} a {approx} 1180 cm{sup -1}. Une etude preparative, analytique et spectroscopique des solides obtenus par precipitation de sels d'uranyle par les phosphates butyliques acides a ete effectuee. La spectrophotomerie infrarouge met en evidence l'association, anterieure a toute introduction d'uranium, des phosphates tributylique et dibutylique dans des diluants non polaires. L'extraction de sels d'uranyle, d'une solution aqueuse acide par un melange dilue de phosphates tributylique et dibutylique, s'effectue suivant des processus differents a la nature de l'anion (nitrate ou chlorure). (auteur)

Sphingomyelinase D activity in model membranes: structural effects of in situ generation of ceramide-1-phosphate.

Directory of Open Access Journals (Sweden)

Roberto P Stock

Full Text Available The toxicity of Loxosceles spider venom has been attributed to a rare enzyme, sphingomyelinase D, which transforms sphingomyelin to ceramide-1-phosphate. The bases of its inflammatory and dermonecrotic activity, however, remain unclear. In this work the effects of ceramide-1-phosphate on model membranes were studied both by in situ generation of this lipid using a recombinant sphingomyelinase D from the spider Loxosceles laeta and by pre-mixing it with sphingomyelin and cholesterol. The systems of choice were large unilamellar vesicles for bulk studies (enzyme kinetics, fluorescence spectroscopy and dynamic light scattering and giant unilamellar vesicles for fluorescence microscopy examination using a variety of fluorescent probes. The influence of membrane lateral structure on the kinetics of enzyme activity and the consequences of enzyme activity on the structure of target membranes containing sphingomyelin were examined. The findings indicate that: 1 ceramide-1-phosphate (particularly lauroyl ceramide-1-phosphate can be incorporated into sphingomyelin bilayers in a concentration-dependent manner and generates coexistence of liquid disordered/solid ordered domains, 2 the activity of sphingomyelinase D is clearly influenced by the supramolecular organization of its substrate in membranes and, 3 in situ ceramide-1-phosphate generation by enzymatic activity profoundly alters the lateral structure and morphology of the target membranes.

Kinetic and thermodynamic study of the reaction catalyzed by glucose-6-phosphate dehydrogenase with nicotinamide adenine dinucleotide

International Nuclear Information System (INIS)

Martin del Campo, Julia S.; Patino, Rodrigo

2011-01-01

Research highlights: → The reaction catalyzed by one enzyme of the pentose phosphate pathway was studied. → A spectrophotometric method is proposed for kinetic and thermodynamic analysis. → The pH and the temperature influences are reported on physical chemical properties. → Relative concentrations of substrates are also important in the catalytic process. - Abstract: The enzyme glucose-6-phosphate dehydrogenase (G6PD, EC 1.1.1.49) from Leuconostoc mesenteroides has a dual coenzyme specificity with oxidized nicotinamide adenine dinucleotide (NAD ox ) and oxidized nicotinamide adenine dinucleotide phosphate as electron acceptors. The G6PD coenzyme selection is determined by the metabolic cellular prevailing conditions. In this study a kinetic and thermodynamic analysis is presented for the reaction catalyzed by G6PD from L. mesenteroides with NAD ox as coenzyme in phosphate buffer. For this work, an in situ spectrophotometric technique was employed based on the detection of one product of the reaction. Substrate and coenzyme concentrations as well as temperature and pH effects were evaluated. The apparent equilibrium constant, the Michaelis constant, and the turnover number were determined as a function of each experimental condition. The standard transformed Gibbs energy of reaction was determined from equilibrium constants at different initial conditions. For the product 6-phospho-D-glucono-1,5-lactone, a value of the standard Gibbs energy of formation is proposed, Δ f G o = -1784 ± 5 kJ mol -1 .

Kinetic and thermodynamic study of the reaction catalyzed by glucose-6-phosphate dehydrogenase with nicotinamide adenine dinucleotide

Energy Technology Data Exchange (ETDEWEB)

Martin del Campo, Julia S. [Departamento de Fisica Aplicada, Centro de Investigacion y de Estudios Avanzados - Unidad Merida, Carretera antigua a Progreso Km. 6, A.P. 73 Cordemex, 97310, Merida, Yucatan (Mexico); Patino, Rodrigo, E-mail: rtarkus@mda.cinvestav.mx [Departamento de Fisica Aplicada, Centro de Investigacion y de Estudios Avanzados - Unidad Merida, Carretera antigua a Progreso Km. 6, A.P. 73 Cordemex, 97310, Merida, Yucatan (Mexico)

2011-04-20

Research highlights: {yields} The reaction catalyzed by one enzyme of the pentose phosphate pathway was studied. {yields} A spectrophotometric method is proposed for kinetic and thermodynamic analysis. {yields} The pH and the temperature influences are reported on physical chemical properties. {yields} Relative concentrations of substrates are also important in the catalytic process. - Abstract: The enzyme glucose-6-phosphate dehydrogenase (G6PD, EC 1.1.1.49) from Leuconostoc mesenteroides has a dual coenzyme specificity with oxidized nicotinamide adenine dinucleotide (NAD{sub ox}) and oxidized nicotinamide adenine dinucleotide phosphate as electron acceptors. The G6PD coenzyme selection is determined by the metabolic cellular prevailing conditions. In this study a kinetic and thermodynamic analysis is presented for the reaction catalyzed by G6PD from L. mesenteroides with NAD{sub ox} as coenzyme in phosphate buffer. For this work, an in situ spectrophotometric technique was employed based on the detection of one product of the reaction. Substrate and coenzyme concentrations as well as temperature and pH effects were evaluated. The apparent equilibrium constant, the Michaelis constant, and the turnover number were determined as a function of each experimental condition. The standard transformed Gibbs energy of reaction was determined from equilibrium constants at different initial conditions. For the product 6-phospho-D-glucono-1,5-lactone, a value of the standard Gibbs energy of formation is proposed, {Delta}{sub f}G{sup o} = -1784 {+-} 5 kJ mol{sup -1}.

Eu{sup 3+} emission in phosphate glasses with high UV transparency

Energy Technology Data Exchange (ETDEWEB)

Silva, G.H. [Laboratório de Espectroscopia de Materiais (LEM), Departamento de Física, Universidade Federal de Juiz de Fora, CEP 36036-900 Juiz de Fora, MG (Brazil); Anjos, V., E-mail: virgilio@fisica.ufjf.br [Laboratório de Espectroscopia de Materiais (LEM), Departamento de Física, Universidade Federal de Juiz de Fora, CEP 36036-900 Juiz de Fora, MG (Brazil); Bell, M.J.V. [Laboratório de Espectroscopia de Materiais (LEM), Departamento de Física, Universidade Federal de Juiz de Fora, CEP 36036-900 Juiz de Fora, MG (Brazil); Carmo, A.P. [Instituto Federal Fluminense-Campus Cabo Frio, CP 112015, CEP 28909-971 Cabo Frio, RJ (Brazil); Pinheiro, A.S.; Dantas, N.O. [Laboratório de Novos Materiais Isolantes e Semicondutores (LNMIS), Instituto de Física, Universidade Federal de Uberlândia, CP 593, CEP 38400-902 Uberlândia, MG (Brazil)

2014-10-15

We report a study of the phosphate glass PZABP (P{sub 2}O{sub 5}–ZnO–Al{sub 2}O{sub 3}–BaO–PbO) doped with europium (Eu{sup 3+}) in different concentrations. Absorption, photoluminescence and time resolved photoluminescence were used to investigate the influence of increasing Eu{sup 3+} concentrations. The present glass exhibits Eu{sup 3+} absorption bands in the ultraviolet region (about 300 nm) due to the high transparency of the system compared to other phosphate glasses. In this way, it was possible to obtain the Judd–Ofelt parameters from the emission and absorption spectra. Moreover, a strong red emission attributed to the transition {sup 5}D{sub 0}→{sup 7}F{sub 2} of Eu{sup 3+} (611 nm) was observed. It was found that the radiative lifetime and the quantum efficiency of the Eu{sup 3+} level, {sup 5}D{sub 0}, do not suffer a significant change as the concentration of Eu{sup 3+} ions increases. - Highlights: • UV transparent glass matrix is used for Eu{sup 3+} doping. • Judd–Ofelt parameters from the emission and absorption spectra were obtained. • Red emission attributed to the transition {sup 5}D{sub 0}→{sup 7}F{sub 2} of Eu{sup 3+} (611 nm) was observed.

Neonatal jaundice and glucose-6-phosphate dehydrogenase

OpenAIRE

Leite, Amauri Antiquera [UNESP

2010-01-01

A deficiência de glicose-6-fosfato desidrogenase em neonatos pode ser a responsável pela icterícia neonatal. Este comentário científico é decorrente do relato sobre o tema publicado neste fascículo e que preocupa diversos autores de outros países em relação às complicações em neonatos de hiperbilirrubinemia, existindo inclusive proposições de alguns autores em incluir o teste para identificar a deficiência de glicose-6-fosfato desidrogenase nos recém-nascidos.Glucose-6-phosphate dehydrogenase...

Born-Infeld-Goldstone superfield actions for gauge-fixed D5- and D3-branes in 6d

International Nuclear Information System (INIS)

Ketov, Sergei V.

1999-01-01

The supersymmetric Born-Infeld actions describing gauge-fixed D-5- and D3-branes in ambient six-dimensional (6d) space-time are constructed in superspace. A new 6d action is the (1,0) supersymmetric extension of the 6d Born-Infeld action. It is related via dimensional reduction to another remarkable 4d action describing the N = 2 supersymmetric extension of the Born-Infeld-Nambu-Goto action with two real scalats. Both actions are the Goldstone actions associated with partial (((1)/(2))) spontaneous breaking of extended supersymmetry having 16 supercharges down to 8 supercharges. Both actions can be put into the 'non-linear sigma-model' form by using certain non-linear superfield constraints. The unbroken supersymmetry is always linearly realised in our construction

Intensive Hemodialysis, Mineral and Bone Disorder, and Phosphate Binder Use.

Science.gov (United States)

Copland, Michael; Komenda, Paul; Weinhandl, Eric D; McCullough, Peter A; Morfin, Jose A

2016-11-01

Mineral and bone disorder is a common complication of end-stage renal disease. Notably, hyperphosphatemia likely promotes calcification of the myocardium, valves, and arteries. Hyperphosphatemia is associated with higher risk for cardiovascular mortality and morbidity along a gradient beginning at 5.0mg/dL. Among contemporary hemodialysis (HD) patients, mean serum phosphorus level is 5.2mg/dL, although 25% of patients have serum phosphorus levels of 5.5 to 6.9mg/dL; and 13%, >7.0mg/dL. Treatment of hyperphosphatemia is burdensome. Dialysis patients consume a mean of 19 pills per day, half of which are phosphate binders. Medicare Part D expenditures on binders for dialysis patients approached $700 million in 2013. Phosphorus removal with thrice-weekly HD (4 hours per session) is ∼3,000mg/wk. However, clearance is unlikely to counterbalance dietary intake, which varies around a mean of 7,000mg/wk. Dietary restriction and phosphate binders are important interventions, but each has limitations. Dietary control is complicated by limited access to healthy food choices and unclear labeling. Meanwhile, adherence to phosphate binders is poor, especially in younger patients and those with high pill burden. Multiple randomized clinical trials show that intensive HD reduces serum phosphorus levels. In the Frequent Hemodialysis Network (FHN) trial, short daily and nocturnal schedules reduced serum phosphorus levels by 0.6 and 1.6mg/dL, respectively, relative to 3 sessions per week. A similar effect of nocturnal HD was observed in an earlier trial. In the daily arm of the FHN trial, intensive HD significantly lowered estimated phosphate binder dose per day, whereas in the nocturnal arm, intensive HD led to binder discontinuation in 75% of patients. However, intensive HD appears to have no meaningful effects on serum calcium and parathyroid hormone concentrations. In conclusion, intensive HD, especially nocturnal HD, lowers serum phosphorus levels and decreases the need for

A third-generation dispersion and third-generation hydrogen bonding corrected PM6 method: PM6-D3H+

Directory of Open Access Journals (Sweden)

Jimmy C. Kromann

2014-06-01

Full Text Available We present new dispersion and hydrogen bond corrections to the PM6 method, PM6-D3H+, and its implementation in the GAMESS program. The method combines the DFT-D3 dispersion correction by Grimme et al. with a modified version of the H+ hydrogen bond correction by Korth. Overall, the interaction energy of PM6-D3H+ is very similar to PM6-DH2 and PM6-DH+, with RMSD and MAD values within 0.02 kcal/mol of one another. The main difference is that the geometry optimizations of 88 complexes result in 82, 6, 0, and 0 geometries with 0, 1, 2, and 3 or more imaginary frequencies using PM6-D3H+ implemented in GAMESS, while the corresponding numbers for PM6-DH+ implemented in MOPAC are 54, 17, 15, and 2. The PM6-D3H+ method as implemented in GAMESS offers an attractive alternative to PM6-DH+ in MOPAC in cases where the LBFGS optimizer must be used and a vibrational analysis is needed, e.g., when computing vibrational free energies. While the GAMESS implementation is up to 10 times slower for geometry optimizations of proteins in bulk solvent, compared to MOPAC, it is sufficiently fast to make geometry optimizations of small proteins practically feasible.

Molecular association of glucose-6-phosphate isomerase and pyruvate kinase M2 with glyceraldehyde-3-phosphate dehydrogenase in cancer cells

International Nuclear Information System (INIS)

Das, Mahua R.; Bag, Arup K.; Saha, Shekhar; Ghosh, Alok; Dey, Sumit K.; Das, Provas; Mandal, Chitra; Ray, Subhankar; Chakrabarti, Saikat; Ray, Manju; Jana, Siddhartha S.

2016-01-01

For a long time cancer cells are known for increased uptake of glucose and its metabolization through glycolysis. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a key regulatory enzyme of this pathway and can produce ATP through oxidative level of phosphorylation. Previously, we reported that GAPDH purified from a variety of malignant tissues, but not from normal tissues, was strongly inactivated by a normal metabolite, methylglyoxal (MG). Molecular mechanism behind MG mediated GAPDH inhibition in cancer cells is not well understood. GAPDH was purified from Ehrlich ascites carcinoma (EAC) cells based on its enzymatic activity. GAPDH associated proteins in EAC cells and 3-methylcholanthrene (3MC) induced mouse tumor tissue were detected by mass spectrometry analysis and immunoprecipitation (IP) experiment, respectively. Interacting domains of GAPDH and its associated proteins were assessed by in silico molecular docking analysis. Mechanism of MG mediated GAPDH inactivation in cancer cells was evaluated by measuring enzyme activity, Circular dichroism (CD) spectroscopy, IP and mass spectrometry analyses. Here, we report that GAPDH is associated with glucose-6-phosphate isomerase (GPI) and pyruvate kinase M2 (PKM2) in Ehrlich ascites carcinoma (EAC) cells and also in 3-methylcholanthrene (3MC) induced mouse tumor tissue. Molecular docking analyses suggest C-terminal domain preference for the interaction between GAPDH and GPI. However, both C and N termini of PKM2 might be interacting with the C terminal domain of GAPDH. Expression of both PKM2 and GPI is increased in 3MC induced tumor compared with the normal tissue. In presence of 1 mM MG, association of GAPDH with PKM2 or GPI is not perturbed, but the enzymatic activity of GAPDH is reduced to 26.8 ± 5 % in 3MC induced tumor and 57.8 ± 2.3 % in EAC cells. Treatment of MG to purified GAPDH complex leads to glycation at R399 residue of PKM2 only, and changes the secondary structure of the protein complex. PKM2

Prevalence of Sickle Cell Trait and Glucose 6 Phosphate ...

African Journals Online (AJOL)

Blood donation from sickle cell trait (SCT) and glucose-6-phosphate dehydrogenase (G6PD)-deficient donors might alter the quality of the donated blood during processing, storage or in the recipients' circulatory system. The aim of this study was to determine the prevalence of SCT and G6PD deficiency among blood ...

EFFECTS OF SODIUM PHOSPHATE LOADING ON AEROBIC POWER AND CAPACITY IN OFF ROAD CYCLISTS

Directory of Open Access Journals (Sweden)

Scott Woska

2009-12-01

Full Text Available The main aim of this paper was to evaluate the effects of short- term (6 days phosphate loading, as well as prolonged (21 days intake of sodium phosphate on aerobic capacity in off-road cyclists. Nineteen well-trained cyclists were randomly divided into a supplemental (S and control group (C. Group S was supplemented for 6 days with tri-sodium phosphate, in a dose of 50 mg·kg-1 of FFM/d, while a placebo was provided for the C group. Additionally, group S was further subjected to a 3-week supplementation of 25 mg·kg-1 FFM/d, while group C received 2g of glucose. The results indicate a significant (p < 0.05 increase in VO2max, VEmax, and O2/HR, due to sodium phosphate intake over 6 days. Also a significant (p < 0.05 decrease in HRrest and HRmax occurred. The supplementation procedure caused a significant increase (p < 0.05 in Pmax and a shift of VAT towards higher loads. There were no significant changes in the concentration of 2,3-DPG, acid-base balance and lactate concentration, due to phosphate salt intake

In Situ Wire Drawing of Phosphate Glass in Polymer Matrices for Material Extrusion 3D Printing

Directory of Open Access Journals (Sweden)

J. Gilberto Siqueiros

2017-01-01

Full Text Available A strategy to increase the amount of materials available for additive manufacturing platforms such as material extrusion 3D printing (ME3DP is the creation of printable thermoplastic composites. Potential limiters to the incorporation of filler materials into a thermoplastic resin include agglomeration of the filler materials, which can compromise the mechanical properties of the material system and a static morphology of the filler material. A potential solution to these issues is the use of filler materials with low glass transition temperatures allowing for a change in morphology during the extrusion process. Here, we successfully demonstrate the drawing of phosphate glass particles into a wire-like morphology within two polymeric systems: (1 a rubberized acrylonitrile butadiene styrene (ABS blend and (2 polylactic acid (PLA. After applying a normalization process to account for the effect of air gap within the 3D printed test specimens, an enhancement in the mechanical properties was demonstrated where an increase in strength was as high as 21% over baseline specimens. Scanning electron microanalysis was used to characterize the fracture surface and wire drawing efficacy. Factors affecting the ability to achieve wire drawing such as polymer viscosity and print temperature are also highlighted.

Triiodothyronine (T3)-associated upregulation and downregulation of nuclear T3 binding in the human fibroblast cell (MRC-5)--stimulation of malic enzyme, glucose-6-phosphate-dehydrogenase, and 6-phosphogluconate-dehydrogenase by insulin, but not by T3

DEFF Research Database (Denmark)

Matzen, L E; Kristensen, S R; Kvetny, J

1991-01-01

The specific nuclear binding of triiodothyronine (T3) (NBT3) and the activity of malic enzyme (ME), glucose-6-phosphate-dehydrogenase (G6PD), and 6-phosphogluconate-dehydrogenase (6PGD) were studied in the human fibroblast cell (MRC-5). The overall apparent binding affinity (Ka) was 2.7 x 10(9) L.......mol-1 estimated from kinetic studies of nuclear T3 binding, and 2.5 x 10(9) L.mol-1 estimated from equilibrium studies. The scatchard plots were curvilinear and composed of a high-affinity binding site with Ka1 3.4 +/- 0.7 x 10(9) L.mol-1 and maximal binding capacity (MBC) MBC1 57.0 +/- 11.9 fmol/mg DNA...... and a low-affinity binding site with Ka2 2.9 +/- 1.1 x 10(8) L.mol-1 and MBC2 124.7 +/- 22.1 fmol/mg DNA (n = 6). Incubation of cells with 6 nmol/L T3 for 20 hours reduced NBT3 to 62.2% +/- 15.7% (P less than .01, n = 11). The Ka estimated from kinetic studies was reduced to 6.7 x 10(7) L.mol-1...

Inhibition of mitochondrial glycerol-3-phosphate dehydrogenase by alpha-tocopheryl succinate

Czech Academy of Sciences Publication Activity Database

Rauchová, Hana; Vokurková, Martina; Drahota, Zdeněk

2014-01-01

Roč. 53, AUG (2014), s. 409-413 ISSN 1357-2725 R&D Projects: GA ČR(CZ) GAP304/12/0259 Institutional support: RVO:67985823 Keywords : brown adipose tissue mitochondria * oxygen consumption * glycerol-3-phosphate * succinate * reactive oxygen species Subject RIV: ED - Physiology Impact factor: 4.046, year: 2014

Basic hydrolysis of 1, 3, 4, 6-tetra-O-acetyl-2-[18F] fluoro-D-glucose on solid phase extraction

International Nuclear Information System (INIS)

Zhang Jinming; Tian Jiahe; He Yijie; Huan Dingcai; Liu Boli

2003-01-01

A new base hydrolysis method are used for 1, 3, 4, 6-tetra-O-acetyl-2-[ 18 F] fluoro-D-glucose on solid phase extraction. The labeled intermediate is trapped on an active C-18 solid phase extraction cartridge, and hydrolyzed in cartridge with 1 mL 2 mol/L NaOH at room temperature. The results show that there are over 99% of the labeled intermediate being turned into 18 F-FDG within 2 min. It is easy to get 18 F-FDG after neutralized with phosphate buffer, purified by C-18 and Alumina cartridge. The basic hydrolysis on solid extraction is a simple method for preparation of 18 F-FDG

Comparison of fluorescent tags for analysis of mannose-6-phosphate glycans.

Science.gov (United States)

Kang, Ji-Yeon; Kwon, Ohsuk; Gil, Jin Young; Oh, Doo-Byoung

2016-05-15

Mannose-6-phosphate (M-6-P) glycan analysis is important for quality control of therapeutic enzymes for lysosomal storage diseases. Here, we found that the analysis of glycans containing two M-6-Ps was highly affected by the hydrophilicity of the elution solvent used in high-performance liquid chromatography (HPLC). In addition, the performances of three fluorescent tags--2-aminobenzoic acid (2-AA), 2-aminobenzamide (2-AB), and 3-(acetyl-amino)-6-aminoacridine (AA-Ac)--were compared with each other for M-6-P glycan analysis using HPLC and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The best performance for analyzing M-6-P glycans was shown by 2-AA labeling in both analyses. Copyright © 2016 Elsevier Inc. All rights reserved.

Design, synthesis and in vitro evaluation on glucosamine-6P synthase of aromatic analogs of 2-Aminohexitols-6P

Energy Technology Data Exchange (ETDEWEB)

Dias, Danielle F.; Alves, Ricardo J., E-mail: ricardodylan@farmacia.ufmg.b [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Faculdade de Farmacia; Roux, Celine; Durand, Philippe; Iorga, Bogdan; Badet-Denisot, Marie A.; Badet, Bernard [Centre National de la Recherche Scientifique (CNRS), Gif-sur-Yvette (France). Inst. de Chimie des Substances Naturelles

2010-07-01

The aminosugars are very important structural components of bacterial and fungi cell walls. Glucosamine-6-phosphate synthase (GlmS), which catalyses the first step of the aminosugar biosynthetic pathway i.e. the formation of D-glucosamine-6-phosphate from D-fructose-6-phosphate, is therefore an interesting target in the fight against microorganisms. In this work is described the synthesis of aromatic analogs of 2-amino-2-deoxy-D-glucitol-6-phosphate (ADGP) and its epimer 2-amino-2-deoxy-D-manitol-6-phosphate (ADMP), two important inhibitors of GlmS. The aromatic analogs displayed modest inhibitory activity against GlmS, with IC{sub 50} in the mmol L{sup -1} range. (author)

Breaking the Dogma of Aldolase Specificity: Simple Aliphatic Ketones and Aldehydes are Nucleophiles for Fructose-6-phosphate Aldolase.

Science.gov (United States)

Roldán, Raquel; Sanchez-Moreno, Israel; Scheidt, Thomas; Hélaine, Virgil; Lemaire, Marielle; Parella, Teodor; Clapés, Pere; Fessner, Wolf-Dieter; Guérard-Hélaine, Christine

2017-04-11

d-Fructose-6-phosphate aldolase (FSA) was probed for extended nucleophile promiscuity by using a series of fluorogenic substrates to reveal retro-aldol activity. Four nucleophiles ethanal, propanone, butanone, and cyclopentanone were subsequently confirmed to be non-natural substrates in the synthesis direction using the wild-type enzyme and its D6H variant. This exceptional widening of the nucleophile substrate scope offers a rapid entry, in good yields and high stereoselectivity, to less oxygenated alkyl ketones and aldehydes, which was hitherto impossible. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Engineering the donor selectivity of D-fructose-6-phosphate aldolase for biocatalytic asymmetric cross-aldol additions of glycolaldehyde.

Science.gov (United States)

Szekrenyi, Anna; Soler, Anna; Garrabou, Xavier; Guérard-Hélaine, Christine; Parella, Teodor; Joglar, Jesús; Lemaire, Marielle; Bujons, Jordi; Clapés, Pere

2014-09-22

D-Fructose-6-phosphate aldolase (FSA) is a unique catalyst for asymmetric cross-aldol additions of glycolaldehyde. A combination of a structure-guided approach of saturation mutagenesis, site-directed mutagenesis, and computational modeling was applied to construct a set of FSA variants that improved the catalytic efficiency towards glycolaldehyde dimerization up to 1800-fold. A combination of mutations in positions L107, A129, and A165 provided a toolbox of FSA variants that expand the synthetic possibilities towards the preparation of aldose-like carbohydrate compounds. The new FSA variants were applied as highly efficient catalysts for cross-aldol additions of glycolaldehyde to N-carbobenzyloxyaminoaldehydes to furnish between 80-98 % aldol adduct under optimized reaction conditions. Donor competition experiments showed high selectivity for glycolaldehyde relative to dihydroxyacetone or hydroxyacetone. These results demonstrate the exceptional malleability of the active site in FSA, which can be remodeled to accept a wide spectrum of donor and acceptor substrates with high efficiency and selectivity. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simion 3D Version 6.0 User`s Manual

Energy Technology Data Exchange (ETDEWEB)

Dahl, D.A.

1995-11-01

The original SIMION was an electrostatic lens analysis and design program developed by D.C. McGilvery at Latrobe University, Bundoora Victoria, Australia, 1977. SIMION for the PC, developed at the Idaho National Engineering Laboratory, shares little more than its name with the original McGilvery version. INEL`s fifth major SIMION release, version 6.0, represents a quantum improvement over previous versions. This C based program can model complex problems using an ion optics workbench that can hold up to 200 2D and/or 3D electrostatic/magnetic potential arrays. Arrays can have up to 10,000,000 points. SIMION 3D`s 32 bit virtual Graphics User Interface provides a highly interactive advanced user environment. All potential arrays are visualized as 3D objects that the user can cut away to inspect ion trajectories and potential energy surfaces. User programs have been greatly extended in versatility and power. A new geometry file option supports the definition of highly complex array geometry. Extensive algorithm modifications have dramatically improved this version`s computational speed and accuracy.

Evaluation of Glucose-6-Phosphate Dehydrogenase stability in stored blood samples.

Science.gov (United States)

Jalil, Norunaluwar; Azma, Raja Zahratul; Mohamed, Emida; Ithnin, Azlin; Alauddin, Hafiza; Baya, Siti Noor; Othman, Ainoon

2016-01-01

Glucose-6-Phosphate Dehydrogenase (G6PD) deficiency is the commonest cause of neonatal jaundice in Malaysia. Recently, OSMMR2000-D G6PD Assay Kit has been introduced to quantitate the level of G6PD activity in newborns delivered in Universiti Kebangsaan Malaysia Medical Centre (UKMMC). As duration of sample storage prior to analysis is one of the matters of concern, this study was conducted to identify the stability of G6PD enzyme during storage. A total of 188 cord blood samples from normal term newborns delivered at UKMMC were selected for this study. The cord bloods samples were collected in ethylene-diamine-tetra-acetic acid (EDTA) tubes and refrigerated at 2-8 °C. In addition, 32 out of 188 cord blood samples were spotted on chromatography paper, air-dried and stored at room temperature. G6PD enzyme activities were measured daily for 7 days using the OSMMR2000-D G6PD Assay Kit on both the EDTA blood and dried blood samples. The mean value for G6PD activity was compared between days of analysis using Student Paired T-Test. In this study, 172 out of 188 cord blood samples showed normal enzyme levels while 16 had levels corresponding to severe enzyme deficiency. The daily mean G6PD activity for EDTA blood samples of newborns with normal G6PD activity showed a significant drop on the fourth day of storage (p samples with severely deficient G6PD activity, significant drop was seen on third day of storage (p = 0.002). Analysis of dried cord blood showed a significant reduction in enzyme activity as early as the second day of storage (p = 0.001). It was also noted that mean G6PD activity for spotted blood samples were lower compared to those in EDTA tubes for all days (p = 0.001). Thus, EDTA blood samples stored at 2-8 °C appeared to have better stability in terms of their G6PD enzyme level as compared to dried blood samples on filter paper, giving a storage time of up to 3 days.

Phosphate Tether-Mediated Ring-Closing Metathesis for the Generation of P-Stereogenic, Z-Configured Bicyclo[7.3.1]- and Bicyclo[8.3.1]phosphates.

Science.gov (United States)

Markley, Jana L; Maitra, Soma; Hanson, Paul R

2016-02-05

A phosphate tether-mediated ring-closing metathesis (RCM) study to the synthesis of Z-configured, P-stereogenic bicyclo[7.3.1]- and bicyclo[8.3.1]phosphates is reported. Investigations suggest that C3-substitution, olefin substitution, and proximity of the forming olefin to the bridgehead carbon of the bicyclic affect the efficiency and stereochemical outcome of the RCM event. This study demonstrates the utility of phosphate tether-mediated desymmetrization of C2-symmetric, 1,3-anti-diol-containing dienes in the generation of macrocyclic phosphates with potential synthetic and biological utility.

4,2':6',4"- and 3,2':6',3"-Terpyridines: The Conflict between Well-Defined Vectorial Properties and Serendipity in the Assembly of 1D-, 2D- and 3D-Architectures.

Science.gov (United States)

Klein, Y Maximilian; Prescimone, Alessandro; Constable, Edwin C; Housecroft, Catherine E

2017-06-30

A comparative investigation of the coordination assemblies formed between Co(NCS)₂ and two monotopic 4,2':6',4''-terpyridine (4,2':6',4"-tpy) ligands or two related ditopic ligands is reported. Crystals were grown by layering MeOH solutions of Co(NCS)₂ over a CHCl₃ or 1,2-C₆H₄Cl₂ solution of the respective ligand at room temperature. With 4'-(2-methylpyrimidin-5-yl)-4,2':6',4"-terpyridine ( 6 ), the 1D-coordination polymer {[Co₂(NCS)₄(MeOH)₄( 6 )₂]∙2MeOH∙8H₂O} n assembles with 6 coordinating only through the outer N-donors of the 4,2':6',4"-tpy unit; coordination by the MeOH solvent blocks two cobalt coordination sites preventing propagation in a higher-dimensional network. A combination of Co(NCS)₂ and 1-(4,2':6',4"-terpyridin-4'-yl)ferrocene ( 7 ) leads to {[Co(NCS)₂( 7 )₂]∙4CHCl₃} n which contains a (4,4) net; the 2D-sheets associate through π-stacking interactions between ferrocenyl and pyridyl units. A 3D-framework is achieved through use of the ditopic ligand 1,4-bis( n propoxy)-2,5-bis(4,2':6',4"-terpyridin-4'-yl)benzene ( 8 ) which acts as a 4-connecting node in {[Co(NCS)₂( 8 )₂] . 2C₆H₄Cl₂} n ; the combination of metal and ligand planar 4-connecting nodes results in a {6⁵.8} cds net. For a comparison with the coordinating abilities of the previously reported 1,4-bis( n octoxy)-2,5-bis(4,2':6',4"-terpyridin-4'-yl)benzene ( 3 ), a more flexible analogue 9 was prepared. {[Co(NCS)₂( 9 )]∙2CHCl₃} n contains a (4,4) net defined by both metal and ligand planar 4-connecting nodes. The n octoxy tails of 9 protrude from each side of the (4,4) net and thread through adjacent sheets; the arene-attached n octoxy chains associate through a combination of van der Waals and C-H...π interactions.

Polimorfisme Enzim Glucose-6-Phosphate Isomerase pada Tiga Populasi Tuna Sirip Kuning (Thunnus albacares)

OpenAIRE

Permana, Gusti Ngurah; Hutapea, Jhon H.; Moria, Sari Budi; Haryanti, Haryanti

2006-01-01

Samples of yellowfin tuna (Thunnus albacares) were taken from three locations Bali, North Sulawesi and North Maluku. The glucose-6-phosphate isomerase (GPI) was analyzed from liver using allozyme electrophoresis method. Polymorphism of GPI enzyme was observed and four alleles (A, B ,C, D) were found in Bali population, three alleles (A,B,C) were found in North Maluku and North Sulawesi populations. Heterozygosity values, from Bali, North Maluku and North Sulawesi were 0.419; 0.417; 0.143 resp...

Contribution to the study of uranyl salts in butyl phosphate solutions; Contribution a l'etude des solutions de sels d'uranyle dans les phosphates butyliques

Energy Technology Data Exchange (ETDEWEB)

Coulon, A. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

1965-06-01

A spectroscopic study in the normal infrared region and involving the following associations: tri-alkyl phosphates (tri-butyl, tri-ethyl, tri-methyl), uranyl salts (nitrate, chloride, acetate) has confirmed the existence of an interaction between the phosphoryl group and the uranium atom, as shown by a movement of absorption band for the valency P = 0 from {approx} 1270 cm{sup -1} to {approx} 1180 cm{sup -1}. A study of the preparation, analysis and spectroscopy of the solids obtained by the precipitation of uranyl salts by acid butyl phosphates has been carried out. By infrared spectrophotometry it has been shown that the tri-butyl and di-butyl phosphates are associated in non-polar diluents even before the uranium is introduced. The extraction of uranyl salts from acid aqueous solutions by a diluted mixture of tri-butyl and di-butyl phosphates proceeds by different mechanisms according to the nature of the ion (nitrate or chloride). (author) [French] Une etude spectroscopique dans l'infrarouge moyen portant sur les associations: - phosphates trialcoyliques (tributylique - triethylique - trimethylique) - sels d'uranyle (nitrate, chlorure, acetate) a confirme l'existence d'une interaction entre le groupement phosphoryle et l'atome d'uranium, se manifestant par un deplacement de la bande d'absorption de la vibration de valence P = 0 de {approx} 1270 cm{sup -1} a {approx} 1180 cm{sup -1}. Une etude preparative, analytique et spectroscopique des solides obtenus par precipitation de sels d'uranyle par les phosphates butyliques acides a ete effectuee. La spectrophotomerie infrarouge met en evidence l'association, anterieure a toute introduction d'uranium, des phosphates tributylique et dibutylique dans des diluants non polaires. L'extraction de sels d'uranyle, d'une solution aqueuse acide par un melange dilue de phosphates tributylique et dibutylique, s'effectue suivant des processus differents a la

Physiological role of glucose-6-phosphate dehydrogenase in cold acclimation of strawberry (Fragaria × ananassa)

Science.gov (United States)

Zhang, Yong; Yu, Dingqun; Luo, Ya; Wang, Xiaorong; Chen, Qing; Sun, Bo; Wang, Yan; Liu, Zejing; Tang, Haoru

2018-04-01

In recent years, there has been an increasing interest in study of new resistance mechanism in fruit trees. All these regard the climate change and subsequent fruit production. Glucose-6-phosphate dehydrogenase (G6PDH) catalyzes the first and rate-limiting step of the oxidative pentose phosphate pathway (OPPP), and the expression of this enzyme is related to different biotic and abiotic stresses. Under accumulation of low temperature stress, the significant increase in G6PDH activity was found to be closely correlated to the levels of antioxidant enzymes, malondialdehyde (MDA) contents, sugar contents as well as changes of superoxide (O2•-). It is suggested that the enhancement of cold resistance of strawberry, which induced by cold acclimation, related to the significant increase in G6PDH activity. On one hand, G6PDH activates NADPH oxidase to generate reactive oxygen species (ROS); on the other hand, it may be involved in the activation of antioxidant enzymes, and accelerates many other important NADPH-dependent enzymatic reactions. Then further result in the elevation of membrane stability and cold resistance of strawberry. Interestingly, even though the plants were placed again under a temperature of 25°C for 1 d, the higher cold resistance, enzyme activities and soluble sugar content acquired.

Phosphate Metabolism in CKD Stages 3–5: Dietary and Pharmacological Control

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Markus Ketteler

2011-01-01

Full Text Available When compared to the available information for patients on dialysis (CKD stage 5D, data on the epidemiology and appropriate treatment of calcium and phosphate metabolism in the predialysis stages of chronic kidney disease (CKD are quite limited. Perceptible derangements of calcium and phosphate levels start to become apparent when GFR falls below 30 mL/min in some, but not all, patients. However, hyperphosphatemia may be a significant morbidity and mortality risk predictor in predialysis CKD stages. The RIND study, evaluating progression of coronary artery calcification in incident hemodialysis patients, indirectly demonstrated that vascular calcification processes start to manifest in CKD patients prior to the dialysis stage, which may be closely linked to early and invisible derangements in calcium and phosphate homeostasis. Novel insights into the pathophysiology of calcium and phosphate handling such as the discovery of FGF23 and other phosphatonins suggest that a more complex assessment of phosphate balance is warranted, possibly including measurements of fractional phosphate excretion and phosphatonin levels in order to appropriately evaluate disordered metabolism in earlier stages of kidney disease. As a consequence, early and preventive treatment approaches may have to be developed for patients in CKD stages 3-5 to halt progression of CKD-MBD.

Spectroscopic properties of highly Nd-doped lead phosphate glass

Energy Technology Data Exchange (ETDEWEB)

Novais, A.L.F. [Instituto de Física, Universidade Federal de Alagoas, Grupo de Fotônica e Fluidos Complexos, 57072-970 Maceió, AL (Brazil); Dantas, N.O. [Laboratório de Novos Materiais Isolantes e Semicondutores (LNMIS), Instituto de Física, Universidade Federal de Uberlândia, 38400-902 Uberlândia, MG (Brazil); Guedes, I. [Departamento de Física, Universidade Federal do Ceará, Campus do PICI, Caixa Postal 6030, 60455-760 Fortaleza, CE (Brazil); Vermelho, M.V.D., E-mail: vermelho@fis.ufal.br [Instituto de Física, Universidade Federal de Alagoas, Grupo de Fotônica e Fluidos Complexos, 57072-970 Maceió, AL (Brazil)

2015-11-05

The spectroscopic characteristics of highly Nd{sup 3+}-doped lead phosphate glasses (xNd:Pb{sub 3}(PO{sub 4}){sub 2}) have been investigated. The X-ray spectra show that the matrices are glassy up to 25 wt% of Nd{sup 3+} doping. From the Judd–Ofelt analysis we observe that while the Ω{sub (2)} parameter remains constant indicating that the 4f{sup N} and 4f{sup N−1}5 d{sup 1} configurations are not affected by the Nd{sup 3+} doping, the behavior of both Ω{sub (4)} and Ω{sub (6)} changes for 15 wt% of Nd{sup 3+} doping. The reduction of the Ω{sub (6)} parameter is related to the increase of the covalence bonding between the ligands and the Nd{sup 3+} ions. At this particular concentration, the radiative lifetime has a four-fold enhancement. Such behaviors are likely to be related to a modification in the glass structure for high Nd{sup 3+} concentrations. - Graphical abstract: Highly doped lead-phosphate glass matrix, with nominal concentration of up to 25 wt%, maintain the spectroscopic properties without deterioration. The analysis concerning the point of view of Nd{sup 3+} ions showed that high concentrations only affects the rare earth electronic charge density distribution. - Highlights: • Spectroscopic characterization of Nd{sub 2}O{sub 3} highly doped lead phosphate glasses. • Phosphate glass doped with Nd{sup 3+} for applications in photonic devices. • Judd–Ofelt analysis in phosphate glasses doped with Neodymium.

Co-Deposition of a Hydrogel/Calcium Phosphate Hybrid Layer on 3D Printed Poly(Lactic Acid Scaffolds via Dip Coating: Towards Automated Biomaterials Fabrication

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Matthias Schneider

2018-03-01

Full Text Available The article describes the surface modification of 3D printed poly(lactic acid (PLA scaffolds with calcium phosphate (CP/gelatin and CP/chitosan hybrid coating layers. The presence of gelatin or chitosan significantly enhances CP co-deposition and adhesion of the mineral layer on the PLA scaffolds. The hydrogel/CP coating layers are fairly thick and the mineral is a mixture of brushite, octacalcium phosphate, and hydroxyapatite. Mineral formation is uniform throughout the printed architectures and all steps (printing, hydrogel deposition, and mineralization are in principle amenable to automatization. Overall, the process reported here therefore has a high application potential for the controlled synthesis of biomimetic coatings on polymeric biomaterials.

TRPV6 determines the effect of vitamin D3 on prostate cancer cell growth.

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V'yacheslav Lehen'kyi

Full Text Available Despite remarkable advances in the therapy and prevention of prostate cancer it is still the second cause of death from cancer in industrialized countries. Many therapies initially shown to be beneficial for the patients were abandoned due to the high drug resistance and the evolution rate of the tumors. One of the prospective therapeutical agents even used in the first stage clinical trials, 1,25-dihydroxyvitamin D3, was shown to be either unpredictable or inefficient in many cases. We have already shown that TRPV6 calcium channel, which is the direct target of 1,25-dihydroxyvitamin D3 receptor, positively controls prostate cancer proliferation and apoptosis resistance (Lehen'kyi et al., Oncogene, 2007. However, how the known 1,25-dihydroxyvitamin D3 antiproliferative effects may be compatible with the upregulation of pro-oncogenic TRPV6 channel remains a mystery. Here we demonstrate that in low steroid conditions 1,25-dihydroxyvitamin D3 upregulates the expression of TRPV6, enhances the proliferation by increasing the number of cells entering into S-phase. We show that these pro-proliferative effects of 1,25-dihydroxyvitamin D3 are directly mediated via the overexpression of TRPV6 channel which increases calcium uptake into LNCaP cells. The apoptosis resistance of androgen-dependent LNCaP cells conferred by TRPV6 channel is drastically inversed when 1,25-dihydroxyvitamin D3 effects were combined with the successful TRPV6 knockdown. In addition, the use of androgen-deficient DU-145 and androgen-insensitive LNCaP C4-2 cell lines allowed to suggest that the ability of 1,25-dihydroxyvitamin D3 to induce the expression of TRPV6 channel is a crucial determinant of the success or failure of 1,25-dihydroxyvitamin D3-based therapies.

Metabolism of tritiated D-glucose in rat erythrocytes

International Nuclear Information System (INIS)

Manuel y Keenoy, B.; Malaisse-Lagae, F.; Malaisse, W.J.

1991-01-01

The metabolism of D-[U-14C]glucose, D-[1-14C]glucose, D-[6-14C]glucose, D-[1-3H]glucose, D-[2-3H]glucose, D-[3-3H]glucose, D-[3,4-3H]glucose, D-[5-3H]glucose, and D-[6-3H]glucose was examined in rat erythrocytes. There was a fair agreement between the rate of 3HOH production from either D-[3-3H]glucose and D-[5-3H]glucose, the decrease in the 2,3-diphosphoglycerate pool, its fractional turnover rate, the production of 14C-labeled lactate from D-[U-14C]glucose, and the total lactate output. The generation of both 3HOH and tritiated acidic metabolites from D-[3,4-3H]glucose indicated incomplete detritiation of the C4 during interconversion of fructose-1,6-bisphosphate and triose phosphates. Erythrocytes unexpectedly generated 3HOH from D-[6-3H]glucose, a phenomenon possibly attributable to the detritiation of [3-3H]pyruvate in the reaction catalyzed by glutamate pyruvate transaminase. The production of 3HOH from D-[2-3H]glucose was lower than that from D-[5-3H]glucose, suggesting enzyme-to-enzyme tunneling of glycolytic intermediates in the hexokinase/phosphoglucoisomerase/phosphofructokinase sequence. The production of 3HOH from D-[1-3H]glucose largely exceeded that of 14CO2 from D-[1-14C]glucose, a situation tentatively ascribed to the generation of 3HOH in the phosphomannoisomerase reaction. It is further speculated that the adjustment in specific radioactivity of D-[1-3H]glucose-6-phosphate cannot simultaneously match the vastly different degrees of isotopic discrimination in velocity at the levels of the reactions catalyzed by either glucose-6-phosphate dehydrogenase or phosphoglucoisomerase. The interpretation of the present findings thus raises a number of questions, which are proposed as a scope for further investigations

Kernicterus by glucose-6-phosphate dehydrogenase deficiency: a case report and review of the literature

Directory of Open Access Journals (Sweden)

Cossio de Gurrola Gladys

2008-05-01

Full Text Available Abstract Introduction Glucose-6-phosphate dehydrogenase deficiency is an X-linked recessive disease that causes acute or chronic hemolytic anemia and potentially leads to severe jaundice in response to oxidative agents. This deficiency is the most common human innate error of metabolism, affecting more than 400 million people worldwide. Case presentation Here, we present the first documented case of kernicterus in Panama, in a glucose-6-phosphate dehydrogenase-deficient newborn clothed in naphthalene-impregnated garments, resulting in reduced psychomotor development, neurosensory hypoacousia, absence of speech and poor reflex of the pupil to light. Conclusion Mutational analysis revealed the glucose-6-phosphate dehydrogenase Mediterranean polymorphic variant, which explained the development of kernicterus after exposition of naphthalene. As the use of naphthalene in stored clothes is a common practice, glucose-6-phosphate dehydrogenase testing in neonatal screening could prevent severe clinical consequences.

Dietary phosphate restriction normalizes biochemical and skeletal abnormalities in a murine model of tumoral calcinosis.

Science.gov (United States)

Ichikawa, Shoji; Austin, Anthony M; Gray, Amie K; Allen, Matthew R; Econs, Michael J

2011-12-01

Mutations in the GALNT3 gene cause tumoral calcinosis characterized by ectopic calcifications due to persistent hyperphosphatemia. We recently developed Galnt3 knockout mice in a mixed background, which had hyperphosphatemia with increased bone mineral density (BMD) and infertility in males. To test the effect of dietary phosphate intake on their phenotype, Galnt3 knockout mice were generated in the C57BL/6J strain and fed various phosphate diets: 0.1% (low), 0.3% (low normal), 0.6% (normal), and 1.65% (high). Sera were analyzed for calcium, phosphorus, alkaline phosphatase, creatinine, blood urine nitrogen, 1,25-dihydroxyvitamin D, osteocalcin, tartrate-resistant acid phosphatase 5b, and fibroblast growth factor 23 (Fgf23). Femurs were evaluated by dual-energy x-ray absorptiometry, dynamic histomorphometry, and/or microcomputed tomography. Galnt3 knockout mice in C57BL/6J had the same biochemical phenotype observed in our previous study: hyperphosphatemia, inappropriately normal 1,25-dihydroxyvitamin D level, decreased alkaline phosphatase activity, and low intact Fgf23 concentration but high Fgf23 fragments. Skeletal analyses of their femurs revealed significantly high BMD with increased cortical bone area and trabecular bone volume. On all four phosphate diets, Galnt3 knockout mice had consistently higher phosphorus levels and lower alkaline phosphatase and intact Fgf23 concentrations than littermate controls. The low-phosphate diet normalized serum phosphorus, alkaline phosphatase, and areal BMD but failed to correct male infertility in Galnt3 knockout mice. The high-phosphate diet did not increase serum phosphorus concentration in either mutant or control mice due to a compensatory increase in circulating intact Fgf23 levels. In conclusion, dietary phosphate restriction normalizes biochemical and skeletal phenotypes of Galnt3 knockout mice and, thus, can be an effective therapy for tumoral calcinosis.

Crystal structure of a photolysis product of vitamin B6: A pyridodihydrofuran-condensed skeleton compound of pyridoxal 5‧-phosphate

Science.gov (United States)

Aoki, Katsuyuki; Nakamura, Hideyuki; Hattori, Toshiaki; Hu, Ning-Hai; Onishi, Masayoshi

2017-11-01

An aqueous solution dissolving pyridoxal 5‧-phosphate (PLP) was exposed to sun-light at room temperature to yield a photolysis product, 4b,9b-dihydro-4b,9b-dihydroxy-1,6-dimethyl-4,9-bis(phosphonooxymethyl){pyrido[3‧,4‧:2,3]furo[4,5-b]}pyrido[4,3-d]furan (1), whose structure was crystallographically determined. The product 1 was found to be a novel C(sp3)-C(sp3) side-sharing pyridodihydrofuran-condensed skeleton compound with the two pyridodihydrofuran planes taking a 'V-shape'-like molecular configuration. Hydrogen bonding patterns of molecules of 1 in the crystal lattice are analyzed by the graph set approach. The most probable mechanism for the formation of 1 is described.

Analysis of the 3d9ns (n = 5, 6), 3d95p, 3d94f and 3d84s4p configurations of five times ionized arsenic (As VI)

International Nuclear Information System (INIS)

Ryabtsev, A.N.; Gayasov, R.R.; Joshi, Y.N.; Van het Hof, G.J.

1993-01-01

The spectrum of arsenic was photographed in the 100-1250 A region on grazing and normal incidence spectrographs. The spectrum of As VI was extended. Seven out of eight levels of the 3d 9 5s and 6s configurations, 12 out of 12 levels of the 3d 9 5p configuration, 13 out of 20 levels of the 3d 9 4f configuration and 35 levels belonging to the 3d 9 4s4p configuration have been established. Least-Square-Fitted parametric calculations involving configuration interactions both in even and odd parity systems were carried out to adequately interpret the spectrum. One hundred and thirty-two additional lines were classified in the As VI spectrum. A new value of the ionization limit was obtained. Thus, the 3d 9 2 D 5/2 ground level in As VII lies 977500 cm -1 (121.17 eV) above the As VI ground state. (orig.)

3D organic Na4C6O6/graphene architecture for fast sodium storage with ultralong cycle life.

Science.gov (United States)

Gu, Jianan; Gu, Yue; Yang, Shubin

2017-11-23

Sodium-ion batteries (SIBs) have aroused increasing interest as one of the most promising replacements for lithium-ion batteries (LIBs). Here, a novel organic-inorganic 3D Na 4 C 6 O 6 -graphene architecture was successfully fabricated from commercial Na 2 C 6 O 6 and for the first time applied for sodium storage. Hence, the 3D Na 4 C 6 O 6 -graphene architecture exhibits a high reversible capacity, good cyclic performance and high-rate capability for sodium storage.

3-D Image Encryption Based on Rubik's Cube and RC6 Algorithm

Science.gov (United States)

Helmy, Mai; El-Rabaie, El-Sayed M.; Eldokany, Ibrahim M.; El-Samie, Fathi E. Abd

2017-12-01

A novel encryption algorithm based on the 3-D Rubik's cube is proposed in this paper to achieve 3D encryption of a group of images. This proposed encryption algorithm begins with RC6 as a first step for encrypting multiple images, separately. After that, the obtained encrypted images are further encrypted with the 3-D Rubik's cube. The RC6 encrypted images are used as the faces of the Rubik's cube. From the concepts of image encryption, the RC6 algorithm adds a degree of diffusion, while the Rubik's cube algorithm adds a degree of permutation. The simulation results demonstrate that the proposed encryption algorithm is efficient, and it exhibits strong robustness and security. The encrypted images are further transmitted over wireless Orthogonal Frequency Division Multiplexing (OFDM) system and decrypted at the receiver side. Evaluation of the quality of the decrypted images at the receiver side reveals good results.

Phosphorylation and 14-3-3 binding of Arabidopsis trehalose-phosphate synthase 5 in response to 2-deoxyglucose

DEFF Research Database (Denmark)

Harthill, Jean E; Meek, Sarah E M; Morrice, Nick

2006-01-01

Trehalose-6-phosphate is a 'sugar signal' that regulates plant metabolism and development. The Arabidopsis genome encodes trehalose-6-phosphate synthase (TPS) and trehalose-6-phosphatase (TPP) enzymes. It also encodes class II proteins (TPS isoforms 5-11) that contain both TPS-like and TPP...

Acinetobacter baumannii K11 and K83 capsular polysaccharides have the same 6-deoxy-l-talose-containing pentasaccharide K units but different linkages between the K units.

Science.gov (United States)

Kenyon, Johanna J; Shashkov, Alexander S; Senchenkova, Sof'ya N; Shneider, Mikhail M; Liu, Bin; Popova, Anastasiya V; Arbatsky, Nikolay P; Miroshnikov, Konstantin A; Wang, Lei; Knirel, Yuriy A; Hall, Ruth M

2017-10-01

Acinetobacter baumannii produces a variety of capsular polysaccharides (CPS) via genes located at the chromosomal K locus and some KL gene clusters include genes for the synthesis of specific sugars. The structures of K11 and K83 CPS produced by isolates LUH5545 and LUH5538, which carry related KL11a and KL83 gene clusters, respectively, were established by sugar analysis and one- and two-dimensional 1 H and 13 C NMR spectroscopy. Both CPS contain l-rhamnose (l-Rha) and 6-deoxy-l-talose (l-6dTal), and both KL gene clusters include genes for dTDP-l-Rhap synthesis and a tle (talose epimerase) gene encoding an epimerase that converts dTDP-l-Rhap to dTDP-l-6dTalp. The K11 and K83 repeat units are the same pentasaccharide, consisting of d-glucose, l-Rha, l-6dTal, and N-acetyl-d-glucosamine, except that l-6dTal is 2-O-acetylated in K83. However, the K units are linked differently, with l-Rha in the main chain in K11, but as a side-branch in K83. KL11 and KL83 encode unrelated Wzy polymerases that link the K units together and different acetyltransferases, though only Atr8 from KL83 is active. The substrate specificity of each Wzy polymerase was assigned, and the functions of all glycosyltransferases were predicted. The CPS structures produced by three closely related K loci, KL29, KL105 and KL106, were also predicted. Copyright © 2017 Elsevier B.V. All rights reserved.

Study of multicomponent fluoro-phosphate based glasses: Ho3+ as a luminescence center

International Nuclear Information System (INIS)

Babu, S.; Seshadri, M.; Balakrishna, A.; Reddy Prasad, V.; Ratnakaram, Y.C.

2015-01-01

The multicomponent 49.5P 2 O 5 –10AlF 3 –10BaF 2 –10SrF 2 –10PbO–10M (M=Li 2 O, Na 2 O, K 2 O, ZnO and Bi 2 O 3 ) glasses doped with 0.5 mol% holmium were prepared by melt quenching technique. Their thermal behavior was examined from differential scanning calorimetry (DSC). It is found that bismuth fluoro-phosphate glass matrix has good thermal stability. Their structures were characterized by the X-ray diffraction with SEM analysis, fourier transform infrared (FTIR), Raman spectroscopy and magic angle spinning (MAS) nuclear magnetic resonance (NMR) techniques. It was found that the phosphate network of these glasses was composed mainly of Q 2 and Q 3 phosphate tetrahedral units. The Judd–Ofelt parameters (J–O) (Ω 2 , Ω 4 and Ω 6 ) were evaluated from the intensities of the energy levels through optical absorption spectra. The most intense transitions are observed in the visible region of the spectrum. It is observed that the transition 5 I 8 → 5 G 6 is the hypersensitive transition for Ho 3+ ion. With these J–O parameters, various radiative properties like the probabilities of radiative transitions, radiative lifetimes and branching ratios have been calculated for different fluoro-phosphate glasses. The luminescence kinetics from excited holmium levels have been studied upon selective excitation through photoluminescence measurements. Holmium produces two visible laser emissions i.e. one is green ( 5 F 4 ( 5 S 2 )→ 5 I 8 ) and another one is red ( 5 F 5 → 5 I 8 ). The lifetimes of these levels have been experimentally determined through decay profile studies. The above results suggest that the prepared bismuth fluoro-phosphate glass system could be a suitable candidate for using it as a green laser source ( 5 F 4 ( 5 S 2 )→ 5 I 8 ) in the visible region of the spectrum. - Highlights: • Holmium doped different fluoro-phosphate glasses were prepared and characterized. • Structural, thermal and spectroscopic properties have been studied

Natural Rosin-based Phosphate Diester Surfactant Assisted One-step Synthesis of 3D Flowerlikeβ-Ni(OH)2/γ-Ni(OH)2 Composite Nano-microspheres

Institute of Scientific and Technical Information of China (English)

BoShi Wu; Juan Li; ChunRui Han; Feng Xu

2018-01-01

Self-assembled uniform 3Dflowerlikeβ-Ni(OH)2/g-Ni(OH)2composite nano-microspheres with hollow interiors were successfully synthesized via a facile aqueous-ethanol mixed solvothermal method, using nickel sulfate as a precursor, urea as a precipitant, and dehydroabietic based phosphate diester sodium (DDPDS) as a surfactant. The prepared 3D flowerlikeβ-Ni(OH)2/g-Ni(OH)2composite nano-microspheres were tested as supercapacitors in a two-electrode cell with 6 mol/L KOH electrolyte. In addition, the influence of DDPDS concentration on the morphology and size of 3Dflowerlikeβ-Ni(OH)2/g-Ni(OH)2composite nano-microspheres was studied at 180℃. X-ray diffraction (XRD), scanning electron microscopy (SEM), BET(Brunauer, Emmett and Teller)techniques, and equity default swap (EDS) were used to characterize the structure, morphology, and size of the as-prepared samples. Moreover, a possible formation mechanism of the 3Dflowerlikeβ-Ni(OH)2/g-Ni(OH)2composite nano-microspheres was proposed based on the effects of DDPDS concentrationand reaction time. The surfactant micelles were used as soft templates to induce the self-assembly of nanosheets. The crystallinity of the 3D flowerlikeβ-Ni(OH)2/g-Ni(OH)2composite nano-microspheres improved with the increase of DDPDS concentration, and the morphology and size of synthetic nano-microspheres could be controlled.

(1S-1,2-O-Benzylidene-α-d-glucurono-6,3-lactone

Directory of Open Access Journals (Sweden)

David J. Watkin

2009-02-01

Full Text Available X-ray crystallographic analysis has established that the major product from the protection of d-glucoronolactone with benzaldehyde is (1S-1,2-O-benzylidene-α-d-glucurono-6,3-lactone, C13H12O6, rather than the R epimer. The crystal structure exists as O—H...O hydrogen-bonded chains of molecules lying parallel to the a axis. The absolute configuration was determined by the use of d-glucuronolactone as the starting material.

Glucose-6-Phosphate Dehydrogenase: Update and Analysis of New Mutations around the World

Science.gov (United States)

Gómez-Manzo, Saúl; Marcial-Quino, Jaime; Vanoye-Carlo, America; Serrano-Posada, Hugo; Ortega-Cuellar, Daniel; González-Valdez, Abigail; Castillo-Rodríguez, Rosa Angélica; Hernández-Ochoa, Beatriz; Sierra-Palacios, Edgar; Rodríguez-Bustamante, Eduardo; Arreguin-Espinosa, Roberto

2016-01-01

Glucose-6-phosphate dehydrogenase (G6PD) is a key regulatory enzyme in the pentose phosphate pathway which produces nicotinamide adenine dinucleotide phosphate (NADPH) to maintain an adequate reducing environment in the cells and is especially important in red blood cells (RBC). Given its central role in the regulation of redox state, it is understandable that mutations in the gene encoding G6PD can cause deficiency of the protein activity leading to clinical manifestations such as neonatal jaundice and acute hemolytic anemia. Recently, an extensive review has been published about variants in the g6pd gene; recognizing 186 mutations. In this work, we review the state of the art in G6PD deficiency, describing 217 mutations in the g6pd gene; we also compile information about 31 new mutations, 16 that were not recognized and 15 more that have recently been reported. In order to get a better picture of the effects of new described mutations in g6pd gene, we locate the point mutations in the solved three-dimensional structure of the human G6PD protein. We found that class I mutations have the most deleterious effects on the structure and stability of the protein. PMID:27941691

Layered ordering of vacancies of lead iron phosphate Pb{sub 3}Fe{sub 2}(PO{sub 4}){sub 4}

Energy Technology Data Exchange (ETDEWEB)

Malakho, A.P. [Moscow State Univ., Dept. of Material Science (Russian Federation); Morozov, V.A.; Pokholok, V.; Lazoryak, B.I. [Moscow State Univ., Dept. of Chemisty (Russian Federation); Morozov, V.A.; Van Tendeloo, G. [Antwerp Univ., EMAT (Belgium)

2005-07-01

Lead iron phosphate Pb{sub 3}Fe{sub 2}(PO{sub 4}){sub 4} has been synthesized by solid state method and characterized by X-ray powder and electron diffraction, differential scanning calorimetry, Moessbauer and infrared spectroscopy. A structural model for Pb{sub 3}Fe{sub 2}(PO{sub 4}){sub 4} is proposed and is refined by the Rietveld method. The compound crystallizes in the monoclinic space group P2{sub 1}/c with a=9.0065(6) Angstroms, b=9.0574(6) Angstroms, c=9.3057(6) Angstroms, {beta}=116.880(4) degrees, V=677.10(8) (Angstroms){sup 3}, Z=2, R{sub wp}=3.52%, R{sub p}=2.66%. It exhibits a structure with a three-dimensional open framework. The 3D framework is formed by PO{sub 4} tetrahedra and FeO{sub 6} octahedra connected via common vertices. 3/4 of cavities in the framework are occupied by lead and 1/4 are vacant. (authors)

Structural and spectroscopic characteristics of Eu3+-doped tungsten phosphate glasses

Science.gov (United States)

Dousti, M. Reza; Poirier, Gael Yves; de Camargo, Andrea Simone Stucchi

2015-07-01

Tungsten based phosphate glasses are interesting non-crystalline materials, commonly known for photochromic and electrochromic effects, but also promising hosts for luminescent trivalent rare earth ions. Despite very few reports in the literature, association of the host´s functionalities with the efficient emissions of the dopant ions in the visible and near-infrared spectra could lead to novel applications. This work reports the preparation and characterization of glasses with the new composition 4(Sb2O3)96-x(50WO3 50NaPO3)xEu2O3 where x = 0, 0.1, 0.25, 0.5 and 1.0 mol%, obtained by the melt quenching technique. The glasses present large density (∼4.6 g cm-3), high glass transition temperature (∼480 °C) and high thermal stability against crystallization. Upon excitation at 464 nm, the characteristic emissions of Eu3+ ions in the red spectral region are observed with high intensity. The Judd-Ofelt intensity parameters Ω2 = 6.86 × 10-20, Ω4 = 3.22 × 10-20 and Ω6 = 8.2 × 10-20 cm2 were calculated from the emission spectra and found to be higher than those reported for other phosphate glass compositions. An average excited state lifetime value of 1.2 ms, was determined by fitting the luminescence decay curves with single exponential functions and it is comparable or higher than those of other oxide glasses.

The Effects of Fenarimol and Methyl Parathion on Glucose 6-Phosphate Dehydrogenase Enzyme Activity in Rats

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Ferda ARI

2017-10-01

Full Text Available Fenarimol and methyl parathion are pesticides that have been used in agriculture for several years. These pesticides have significant effects on environmental and human health. Therefore, we investigated the effects of methyl parathion and fenarimol on glucose 6-phosphate dehydrogenase (EC 1.1.1.49 enzyme activity in rats. The glucose 6- phosphate dehydrogenase is the first enzyme of the pentose phosphate pathway and it is important in detoxifying reactions by NADPH generated. In this study, wistar albino rats administrated with methyl parathion (7 mg kg–1 and fenarimol (200 mg kg−1 by intraperitoneally for different periods (2, 4, 8, 16, 32, 64, and 72 h. The glucose 6-phosphate dehydrogenase enzyme activity was assayed in liver, kidney, brain, and small intestine in male and female rats. The exposure of fenarimol and methyl parathion caused increase of glucose 6-phosphate dehydrogenase enzyme activity in rat tissues, especially at last periods. We suggest that this increment of enzyme activity may be the reason of toxic effects of fenarimol and methyl parathion.

Intravenous immunoglobulin to treat hyperbilirubinemia in neonates with isolated Glucose-6-Phosphate dehydrogenase deficiency

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Wadah Khriesat

2017-04-01

Full Text Available Background Glucose-6-phosphate dehydrogenase deficiency alone or concomitant with ABO isoimmunisation is a widespread indication for neonatal exchange transfusion. Aims To evaluate the effectiveness of Intravenous Immunoglobulin in the treatment of neonatal hyperbilirubinemia due to glucose-6-phosphate dehydrogenase deficiency. Methods A retrospective cohort study was conducted between 2006 and 2014 at the Jordan University of Science and technology. The medical records of 43 infants admitted to the neonatal intensive care unit for isolated glucose-6- phosphate dehydrogenase deficiency hemolytic disease of the newborns were reviewed. Patients were divided into two groups. Group I, a historical cohort, included newborns born between 2006 and 2010, Treatment included phototherapy and exchange transfusion. Group II included newborns born between 2011 and 2014, where, in addition to phototherapy, intravenous immunoglobulin was administered. The duration of phototherapy and number of exchange transfusions were evaluated. Results Of 412 newborns that were admitted with neonatal hyperbilirubinemia, Glucose-6-phosphate dehydrogenase deficiency was present in 43. Of these, 22, did not receive intravenous immunoglobulin and served as a control group. The other 21 newborns received intravenous immunoglobulin. There was no difference in the demographic characteristics between the two groups. Infants in the control group were significantly more likely to receive exchange blood transfusion than infants in the immunoglobulin treatment group, but were significantly less likely to need phototherapy. Conclusion Intravenous immunoglobulin is an effective alternative to exchange transfusion in infants with glucose-6-phosphate dehydrogenase deficiency hemolytic disease of the newborn. It is suggested that intravenous immunoglobulin may be beneficial as a prophylaxis for infants with hyperbilirubinemia.

The characteristics of pyrophosphate: D-fructose-6-phosphate 1-phosphotransferases from Sansevieria trifasciata leaves and Phaseolus coccineus stems.

Science.gov (United States)

Kowalczyk, S

1987-01-01

Three different molecular forms of pyrophosphate-dependent phosphofructokinase have been isolated: one from Sansevieria trifasciata leaves and two from Phaseolus coccineus stems. The form isolated from S. trifasciata has the molecular weight of about 115,000. The apparent molecular weights for the two forms from mung bean were approximately 220,000 and 450,000. All three forms have the same pH optima, an absolute requirement for Mg2+ ions both in the forward and reverse reaction, but differ in their sensitivity toward fructose 2,6-bisphosphate. Kinetic properties of the partially purified enzymes have been investigated in the presence and absence of fructose 2,6-bisphosphate. Pyrophosphate-dependent phosphofructokinase from S. trifasciata exhibited hyperbolic kinetics with all substrates tested. The saturation curves of the enzyme (form A) from mung bean for pyrophosphate, fructose 6-phosphate and fructose 1,6-bisphosphate were sigmoidal in the absence of fructose 2,6-bisphosphate. In the presence of fructose 2,6-bisphosphate these kinetics became hyperbolic.

Insight into the local magnetic environments and deuteron mobility in jarosite (AFe3(SO4)2(OD)6, A = K, Na, D3O) and hydronium alunite ((D3O)Al3(SO4)2(OD,OD2)6), from variable temperature 2H MAS NMR spectroscopy

DEFF Research Database (Denmark)

Nielsen, Ulla Gro; Heinmaa, Ivo; Samoson, Ago

2011-01-01

to the different temperature dependence of their isotropic shifts. An activation energy of 6.3(4) kJ/mol is determined for the D3O+ motion in the isostructural compound D3OAl3(SO4)2(OD)6. Our NMR results support theories that ascribes the spin glass behavior of (H3O)Fe3(SO4)2(OD)6 is to disorder of the D3O+ ion...... and/or a less distorted Fe coordination environment. No sign of proton transfer reactions from the D3O+ ion to the framework is observed....

2-O-α-D-glucosylglycerol phosphorylase from Bacillus selenitireducens MLS10 possessing hydrolytic activity on β-D-glucose 1-phosphate.

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Takanori Nihira

Full Text Available The glycoside hydrolase family (GH 65 is a family of inverting phosphorylases that act on α-glucosides. A GH65 protein (Bsel_2816 from Bacillus selenitireducens MLS10 exhibited inorganic phosphate (Pi-dependent hydrolysis of kojibiose at the rate of 0.43 s(-1. No carbohydrate acted as acceptor for the reverse phosphorolysis using β-D-glucose 1-phosphate (βGlc1P as donor. During the search for a suitable acceptor, we found that Bsel_2816 possessed hydrolytic activity on βGlc1P with a k cat of 2.8 s(-1; moreover, such significant hydrolytic activity on sugar 1-phosphate had not been reported for any inverting phosphorylase. The H2 (18O incorporation experiment and the anomeric analysis during the hydrolysis of βGlc1P revealed that the hydrolysis was due to the glucosyl-transferring reaction to a water molecule and not a phosphatase-type reaction. Glycerol was found to be the best acceptor to generate 2-O-α-D-glucosylglycerol (GG at the rate of 180 s(-1. Bsel_2816 phosphorolyzed GG through sequential Bi-Bi mechanism with a k cat of 95 s(-1. We propose 2-O-α-D-glucopyranosylglycerol: phosphate β-D-glucosyltransferase as the systematic name and 2-O-α-D-glucosylglycerol phosphorylase as the short name for Bsel_2816. This is the first report describing a phosphorylase that utilizes polyols, and not carbohydrates, as suitable acceptor substrates.

The Effect of 3% Phosphate Ascorbyl Gel on Bond Strength of Composite Resin to Enamel treated with 35% Hydrogen Peroxide.

Science.gov (United States)

de Castro, Milena de Fátima Schalcher; Silva, Alice Carvalho; Franco, Marcela Mayana Pereira; Silva, Ana Paula Brito; Bramante, Fausto da Silva; da Silva, Monica Barros; Lima, Darlon Martins; Pereira, Adriana de Fátima Vasconcelos

2015-05-01

To evaluate the effect of 3% phosphate ascorbyl gel (PA) in different times onto the microshear bond strength of composite resin (CR) to bovine enamel treated with 35% hydrogen peroxide (HP). Thirty enamel blocks of bovine incisors were made and divided into 5 groups (n = 6) with three specimens per group (n = 18), according to treatment: G1= No bleaching + CR; G2 = HP + CR after 15d; G3 = HP + CR after 24 hours; G4 = HP + PA (15 min) + CR after 24 hours; G5 = HP + PA (2 hours) + CR after 24 hours. The resin cylinders were made by Tygon matrices. Microshear bond strength test was performed using universal testing machine with a 50N load at a speed of 0.5 mm/min. Fracture modes were assessed by a stereomicroscope 40 ×. Microshear bond strength values were submitted to the analysis of variance (ANOVA) one-way and Tukey test (p 0.05). Failure modes were categorized into adhesive (90%) and mixed (10%). The use of 3% phosphate ascorbyl gel for 15 minutes was able to improve bond strength of composite resin to bleached bovine enamel, but when 3% phosphate ascorbyl gel was applied during 40 minutes it negatively interfered in the adhesion of the resin to bleached bovine enamel.

Posttranslational regulation of glucose-6-phosphate dehydrogenase activity in tongue epithelium

NARCIS (Netherlands)

Biagiotti, E.; Bosch, K. S.; Ninfali, P.; Frederiks, W. M.; van Noorden, C. J.

2000-01-01

Expression of glucose-6-phosphate dehydrogenase (G6PD) activity is high in tongue epithelium, but its exact function is still unknown, it may be related;either to the high proliferation rate of this tissue or to protection against oxidative stress. To elucidate its exact role, we localized

Mutual effects of copper and phosphate on their interaction with γ-Al2O3: combined batch macroscopic experiments with DFT calculations.

Science.gov (United States)

Ren, Xuemei; Yang, Shitong; Tan, Xiaoli; Chen, Changlun; Sheng, Guodong; Wang, Xiangke

2012-10-30

The mutual effects of Cu(II) and phosphate on their interaction with γ-Al(2)O(3) are investigated by using batch experiments combined with density functional theory (DFT) calculations. The results of batch experiments show that coexisting phosphate promotes the retention of Cu(II) on γ-Al(2)O(3), whereas phosphate retention is not affected by coexisting Cu(II) at low initial phosphate concentrations (≤ 3.6 mg P/L). Cu-phosphate aqueous complexes control Cu(II) retention through the formation of type B ternary surface complexes (where phosphate bridges γ-Al(2)O(3) and Cu(II)) at pH 5.5. This deduction is further supported by the results of DFT calculations. More specifically, the DFT calculation results indicate that the type B ternary surface complexes prefer to form outer-sphere or monodentate inner-sphere binding mode under our experimental conditions. The enhancement of phosphate retention on γ-Al(2)O(3) in the presence of Cu(II) at high initial phosphate concentrations (>3.6 mg P/L) may be attributed to the formation of 1:2 Cu(II)-phosphate species and/or surface precipitates. Understanding the mutual effects of phosphate and Cu(II) on their mobility and transport in mineral/water environments is more realistic to design effective remediation strategies for reducing their negative impacts on aquatic/terrestrial environments. Copyright © 2012 Elsevier B.V. All rights reserved.

The overexpressed human 46-kDa mannose 6-phosphate receptor mediates endocytosis and sorting of β-glucuronidase

International Nuclear Information System (INIS)

Watanabe, H.; Grubb, J.H.; Sly, W.S.

1990-01-01

The authors studied the function of the human small (46-kDa) mannose 6-phosphate receptor (SMPR) in transfected mouse L cells that do not express the larger insulin-like growth factor II/mannose 6-phosphate receptor. Cells overexpressing human SMPR were studied for enzyme binding to cell surface receptors, for binding to intracellular receptors in permeabilized cells, and for receptor-mediated endocytosis of recombinant human β-glucuronidase. Specific binding to human SMPR in permeabilized cells showed a pH optimum between pH 6.0 and pH 6.5. Binding was significant in the present of EDTA but was enhanced by added divalent cations. Up to 2.3% of the total functional receptor could be detected on the cell surface by enzyme binding. They present experiments showing that at very high levels of overexpression, and at pH 6.5, human SMPR mediated the endocytosis of β-glucuronidase. At pH 7.5, the rate of endocytosis was only 14% the rate seen at pH 6.5. Cells overexpressing human SMPR also showed reduced secretion of newly synthesized β-glucuronidase when compared to cells transfected with vector only, suggesting that overexpressed human SMPR can participate in sorting of newly synthesized β-glucuronidase and partially correct the sorting defect in mouse L cells that do not express the insulin-like growth factor II/mannose 6-phosphate receptor

4,2’:6’,4”- and 3,2’:6’,3”-Terpyridines: The Conflict between Well-Defined Vectorial Properties and Serendipity in the Assembly of 1D-, 2D- and 3D-Architectures

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Y. Maximilian Klein

2017-06-01

Full Text Available A comparative investigation of the coordination assemblies formed between Co(NCS2 and two monotopic 4,2’:6’,4’’-terpyridine (4,2’:6’,4”-tpy ligands or two related ditopic ligands is reported. Crystals were grown by layering MeOH solutions of Co(NCS2 over a CHCl3 or 1,2-C6H4Cl2 solution of the respective ligand at room temperature. With 4’-(2-methylpyrimidin-5-yl-4,2’:6’,4”-terpyridine (6, the 1D-coordination polymer {[Co2(NCS4(MeOH4(62]∙2MeOH∙8H2O}n assembles with 6 coordinating only through the outer N-donors of the 4,2’:6’,4”-tpy unit; coordination by the MeOH solvent blocks two cobalt coordination sites preventing propagation in a higher-dimensional network. A combination of Co(NCS2 and 1-(4,2‘:6’,4”-terpyridin-4’-ylferrocene (7 leads to {[Co(NCS2(72]∙4CHCl3}n which contains a (4,4 net; the 2D-sheets associate through π-stacking interactions between ferrocenyl and pyridyl units. A 3D-framework is achieved through use of the ditopic ligand 1,4-bis(npropoxy-2,5-bis(4,2’:6’,4”-terpyridin-4’-ylbenzene (8 which acts as a 4-connecting node in {[Co(NCS2(82].2C6H4Cl2}n; the combination of metal and ligand planar 4-connecting nodes results in a {65.8} cds net. For a comparison with the coordinating abilities of the previously reported 1,4-bis(noctoxy-2,5-bis(4,2’:6’,4”-terpyridin-4’-ylbenzene (3, a more flexible analogue 9 was prepared. {[Co(NCS2(9]∙2CHCl3}n contains a (4,4 net defined by both metal and ligand planar 4-connecting nodes. The noctoxy tails of 9 protrude from each side of the (4,4 net and thread through adjacent sheets; the arene-attached noctoxy chains associate through a combination of van der Waals and C–H...π interactions.

Cytophotometry of glucose-6-phosphate dehydrogenase activity in individual cells

NARCIS (Netherlands)

van Noorden, C. J.; Tas, J.; Vogels, I. M.

1983-01-01

With the aid of thin films of polyacrylamide gel containing purified glucose-6-phosphate dehydrogenase subjected to cytochemical procedures for the enzyme using tetranitro blue tetrazolium, arbitrary units of integrated absorbance obtained with a Barr & Stroud GN5 cytophotometer were converted into

Microstructure and properties of FeSiCr/PA6 composites by injection molding using FeSiCr powders by phosphating and coupling treatment

Science.gov (United States)

Wang, Lulu; Qiao, Liang; Zheng, Jingwu; Cai, Wei; Ying, Yao; Li, Wangchang; Che, Shenglei; Yu, Jing

2018-04-01

FeSiCr/PA6 composites were prepared by injection molding using the FeSiCr powders modified by different phosphating agents and KH550 coupling agent. The resistivity, impact strength, magnetic permeability and magnetic loss of the FeSiCr/PA6 composites were measured. The morphologies of different FeSiCr powders and the FeSiCr/PA6 composites were also observed by scanning electron microscope (SEM). The results showed that 1-Hydroxyethylidene-1,1-diphosphonic acid, phytic acid and H3PO4 could improve the electrical resistivity of FeSiCr powders by forming the dense phosphating layer except diphenylphosphinic acid. However, the resistivity of FeSiCr/PA6 composites using the FeSiCr powders treated by all the four phosphating agents had no obvious increase though the phosphating layer on the surface of FeSiCr powder came into being. The nylon insulation layer had much stronger influence than the phosphating layer on electrical resistivity of the composites. After adding appropriate KH550 coupling agent, the impact strengths of FeSiCr/PA6 composites were significantly improved, which may be associated with the tiny gap between FeSiCr powder and PA6 matrix. The effects of the phosphating agents on the magnetic permeability and loss of the FeSiCr/PA6 were small and the mechanism were also discussed.

Prevalence of thalassaemia, iron-deficiency anaemia and glucose-6-phosphate dehydrogenase deficiency among Arab migrating nomad children, southern Islamic Republic of Iran.

Science.gov (United States)

Pasalar, M; Mehrabani, D; Afrasiabi, A; Mehravar, Z; Reyhani, I; Hamidi, R; Karimi, M

2014-12-17

This study investigated the prevalence of iron-deficiency anaemia, glucose-6-phosphate dehydrogenase (G6PD) deficiency and β-thalassaemia trait among Arab migrating nomad children in southern Islamic Republic of Iran. Blood samples were analysed from 134 schoolchildren aged child had G6PD deficiency. A total of 9.7% of children had HbA2 ≥ 3.5 g/dL, indicating β-thalassaemia trait (10.8% in females and 7.8% in males). Mean serum iron, serum ferritin and total iron binding capacity were similar in males and females. Serum ferritin index was as accurate as Hb index in the diagnosis of iron-deficiency anaemia. A high prevalence of β-thalassaemia trait was the major potential risk factor in this population.

Simultaneous Determination of Ciprofloxacin Hydrochloride and Dexamethasone Sodium Phosphate in Eye Drops by HPLC

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Prakash Katakam

2012-01-01

Full Text Available A liquid chromatographic method was developed and validated for the simultaneous determination of ciprofloxacin hydrochloride and dexamethasone sodium phosphate in bulk and pharmaceutical formulations. Optimum separation was achieved in less than 5 min using a C18 column (250 mmx4.6 mm i.d, 5μ particle size by isocratic elution. The mobile phase consisting of a mixture of mixed phosphate buffer (pH 4 and acetonitrile (65:35, v/v was used. Column effluents were monitored at 254 nm at a flow rate of 1ml/min. Retention times of ciprofloxacin hydrochloride and dexamethasone sodium phosphate were 2.0 and 3.16 min respectively. The linearity of ciprofloxacin hydrochloride and dexamethasone sodium phosphate was in the range of 3-18 μg/ml and 1-6 μg/ml respectively. Developed method was economical in terms of the time taken and amount of solvent consumed for each analysis. The method was validated and successfully applied to the simultaneous determination of ciprofloxacin hydrochloride and dexamethasone sodium phosphate in bulk and pharmaceutical formulations.

A new three-dimensional cobalt phosphate: Co5(OH2)4(HPO4)2(PO4)2

International Nuclear Information System (INIS)

Han Zhangang; Tian Aixiang; Peng Jun; Zhai Xueliang

2006-01-01

A three-dimensional (3D) cobalt phosphate: Co 5 (OH 2 ) 4 (HPO 4 ) 2 (PO 4 ) 2 (1), has been synthesized by hydrothermal reaction and characterized by single-crystal X-ray diffraction, thermogravimetric analysis, and magnetic techniques. The title compound is a template free cobalt phosphate. Compound 1 exhibits a complex net architecture based on edge- and corner-sharing of CoO 6 and PO 4 polyhedra. The magnetic susceptibility measurements indicated that the title compound obeys Curie-Weiss behavior down to a temperature of 17 K at which an antiferromagnetic phase transition occurs. - Graphical abstract: A 3D cobalt phosphate with a neutral framework: Co 5 (OH 2 ) 4 (HPO 4 ) 2 (PO 4 ) 2 (1), has been synthesized and characterized. Compound 1 exhibits a complex net architecture based on edge- and corner-sharing of CoO 6 and PO 4 polyhedra. Its magnetic property was researched

Methodology to reduce 6D patient positional shifts into a 3D linear shift and its verification in frameless stereotactic radiotherapy

Science.gov (United States)

Sarkar, Biplab; Ray, Jyotirmoy; Ganesh, Tharmarnadar; Manikandan, Arjunan; Munshi, Anusheel; Rathinamuthu, Sasikumar; Kaur, Harpreet; Anbazhagan, Satheeshkumar; Giri, Upendra K.; Roy, Soumya; Jassal, Kanan; Kalyan Mohanti, Bidhu

2018-04-01

The aim of this article is to derive and verify a mathematical formulation for the reduction of the six-dimensional (6D) positional inaccuracies of patients (lateral, longitudinal, vertical, pitch, roll and yaw) to three-dimensional (3D) linear shifts. The formulation was mathematically and experimentally tested and verified for 169 stereotactic radiotherapy patients. The mathematical verification involves the comparison of any (one) of the calculated rotational coordinates with the corresponding value from the 6D shifts obtained by cone beam computed tomography (CBCT). The experimental verification involves three sets of measurements using an ArcCHECK phantom, when (i) the phantom was not moved (neutral position: 0MES), (ii) the position of the phantom shifted by 6D shifts obtained from CBCT (6DMES) from neutral position and (iii) the phantom shifted from its neutral position by 3D shifts reduced from 6D shifts (3DMES). Dose volume histogram and statistical comparisons were made between ≤ft and ≤ft . The mathematical verification was performed by a comparison of the calculated and measured yaw (γ°) rotation values, which gave a straight line, Y  =  1X with a goodness of fit as R 2  =  0.9982. The verification, based on measurements, gave a planning target volume receiving 100% of the dose (V100%) as 99.1  ±  1.9%, 96.3  ±  1.8%, 74.3  ±  1.9% and 72.6  ±  2.8% for the calculated treatment planning system values TPSCAL, 0MES, 3DMES and 6DMES, respectively. The statistical significance (p-values: paired sample t-test) of V100% were found to be 0.03 for the paired sample ≤ft and 0.01 for ≤ft . In this paper, a mathematical method to reduce 6D shifts to 3D shifts is presented. The mathematical method is verified by using well-matched values between the measured and calculated γ°. Measurements done on the ArcCHECK phantom also proved that the proposed methodology is correct. The post-correction of the

Glucose-6-phosphate dehydrogenase deficiency in Nigerian children.

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Olatundun Williams

Full Text Available Glucose-6-phosphate dehydrogenase (G6PD deficiency is the most common human enzymopathy and in Sub-Saharan Africa, is a significant cause of infection- and drug-induced hemolysis and neonatal jaundice. Our goals were to determine the prevalence of G6PD deficiency among Nigerian children of different ethnic backgrounds and to identify predictors of G6PD deficiency by analyzing vital signs and hematocrit and by asking screening questions about symptoms of hemolysis. We studied 1,122 children (561 males and 561 females aged 1 month to 15 years. The mean age was 7.4 ± 3.2 years. Children of Yoruba ethnicity made up the largest group (77.5% followed by those Igbo descent (10.6% and those of Igede (10.2% and Tiv (1.8% ethnicity. G6PD status was determined using the fluorescent spot method. We found that the overall prevalence of G6PD deficiency was 15.3% (24.1% in males, 6.6% in females. Yoruba children had a higher prevalence (16.9% than Igede (10.5%, Igbo (10.1% and Tiv (5.0% children. The odds of G6PD deficiency were 0.38 times as high in Igbo children compared to Yoruba children (p=0.0500. The odds for Igede and Tiv children were not significantly different from Yoruba children (p=0.7528 and 0.9789 respectively. Mean oxygen saturation, heart rate and hematocrit were not significantly different in G6PD deficient and G6PD sufficient children. The odds of being G6PD deficient were 2.1 times higher in children with scleral icterus than those without (p=0.0351. In conclusion, we determined the prevalence of G6PD deficiency in Nigerian sub-populations. The odds of G6PD deficiency were decreased in Igbo children compared to Yoruba children. There was no association between vital parameters or hematocrit and G6PD deficiency. We found that a history of scleral icterus may increase the odds of G6PD deficiency, but we did not exclude other common causes of icterus such as sickle cell disease or malarial infection.

ROS generation and multiple forms of mammalian mitochondrial glycerol-3-phosphate dehydrogenase

Czech Academy of Sciences Publication Activity Database

Mráček, Tomáš; Holzerová, Eliška; Drahota, Zdeněk; Kovářová, Nikola; Vrbacký, Marek; Ješina, Pavel; Houštěk, Josef

2014-01-01

Roč. 1837, č. 1 (2014), s. 98-111 ISSN 0005-2728 R&D Projects: GA ČR(CZ) GPP303/10/P227; GA MŠk(CZ) LL1204 Grant - others:Univerzita Karlova(CZ) 750213 Institutional support: RVO:67985823 Keywords : mitochondrial glycerol-3-phosphate dehydrogenase * ROS production * supercomplex * in-gel ROS detection Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 5.353, year: 2014

Kinetic studies of the acylation of pig muscle–d-glyceraldehyde 3-phosphate dehydrogenase by 1,3-diphosphoglycerate and of proton uptake and release in the overall enzyme mechanism

Science.gov (United States)

Harrigan, P. J.; Trentham, D. R.

1973-01-01

In the presence of NAD+ the acylation by 1,3-diphosphoglycerate of the four active sites of pig muscle d-glyceraldehyde 3-phosphate dehydrogenase can be monitored at 365nm by the disappearance of the absorption band present in the binary complex of NAD+ and the enzyme. A non-specific salt effect decreased the acylation rate 25-fold when the ionic strength was increased from 0.10 to 1.0. This caused acylation to be the rate-limiting process in the enzyme-catalysed reductive dephosphorylation of 1,3-diphosphoglycerate at high ionic strength at pH8. The salt effect permitted investigation of the acylation over a wide range of conditions. Variation of pH from 5.4 to 8.6 produced at most a two-fold change in the acylation rate. One proton was taken up per site acylated at pH8.0. By using a chromophoric H+ indicator the rate of proton uptake could be monitored during the acylation and was also almost invariant in the pH range 5.5–8.5. Transient kinetic studies of the overall enzyme-catalysed reaction indicated that acylation was the process involving proton uptake at pH8.0. The enzyme mechanism is discussed in the light of these results. PMID:4360248

Bi–Mn mixed metal organic oxide: A novel 3d-6p mixed metal coordination network

International Nuclear Information System (INIS)

Shi, Fa-Nian; Rosa Silva, Ana; Bian, Liang

2015-01-01

A new terminology of metal organic oxide (MOO) was given a definition as a type of coordination polymers which possess the feature of inorganic connectivity between metals and the direct bonded atoms and show 1D, 2D or 3D inorganic sub-networks. One such compound was shown as an example. A 3d-6p (Mn–Bi. Named MOOMnBi) mixed metals coordination network has been synthesized via hydrothermal method. The new compound with the molecular formula of [MnBi 2 O(1,3,5-BTC) 2 ] n (1,3,5-BTC stands for benzene-1,3,5-tricarboxylate) was characterized via single crystal X-ray diffraction technique that revealed a very interesting 3-dimensional (3D) framework with Bi 4 O 2 (COO) 12 clusters which are further connected to Mn(COO) 6 fragments into a 2D MOO. The topology study indicates an unprecedented topological type with the net point group of (4 13 .6 2 )(4 13 .6 8 )(4 16 .6 5 )(4 18 .6 10 )(4 22 .6 14 )(4 3 ) corresponding to 3,6,7,7,8,9-c hexa-nodal net. MOOMnBi shows catalytic activity in the synthesis of (E)-α,β-unsaturated ketones. - Graphical abstract: This metal organic framework (MOF) is the essence of a 2D metal organic oxide (MOO). - Highlights: • New concept of metal organic oxide (MOO) was defined and made difference from metal organic framework. • New MOO of MOOMnBi was synthesized by hydrothermal method. • Crystal structure of MOOMnBi was determined by single crystal X-ray analysis. • The catalytic activity of MOOMnBi was studied showing reusable after 2 cycles

21 CFR 864.7360 - Erythrocytic glucose-6-phosphate dehydrogenase assay.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Erythrocytic glucose-6-phosphate dehydrogenase assay. 864.7360 Section 864.7360 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Hematology Kits and Packages...

Forward absolute cross-section of the reaction 2H(d,n)3He for Esub(d) = (3/6)MeV

International Nuclear Information System (INIS)

Pavan, P.; Toniolo, D.; Zago, G.; Zannoni, R.; Galeazzi, G.

1981-01-01

The zero-degree differential cross-section of the reaction 2 H(d,n) 3 He was measured, by means of a recoil-proton neutron counter telescope, with an accuracy of 2%, in the incident-deuteron energy interval from 3 to 6 MeV. (author)

Novel cellobiose 2-epimerases for the production of epilactose from milk ultrafiltrate containing lactose.

Science.gov (United States)

Krewinkel, Manuel; Kaiser, Jana; Merz, Michael; Rentschler, Eva; Kuschel, Beatrice; Hinrichs, Jörg; Fischer, Lutz

2015-06-01

A selected number of enzymes have recently been assigned to the emerging class of cellobiose 2-epimerases (CE). All CE convert lactose to the rare sugar epilactose, which is regarded as a new prebiotic. Within this study, the gene products of 2 potential CE genes originating from the mesophilic bacteria Cellulosilyticum lentocellum and Dysgonomonas gadei were recombinantly produced in Escherichia coli and purified by chromatography. The enzymes have been identified as novel CE by sequence analysis and biochemical characterizations. The biochemical characterizations included the determination of the molecular weight, the substrate spectrum, and the kinetic parameters, as well as the pH and temperature profiles in buffer and food matrices. Both identified CE epimerize cellobiose and lactose into the C2 epimerization products glucosylmannose and epilactose, respectively. The epimerization activity for lactose was maximal at pH 8.0 or 7.5 and 40°C in defined buffer systems for the CE from C. lentocellum and the CE from D. gadei, respectively. In addition, biotransformations of the foodstuff milk ultrafiltrate containing lactose were demonstrated. The CE from D. gadei was produced in a stirred-tank reactor (12 L) and purified using an automatic system. Enzyme production and purification in this scale indicates that a future upscaling of CE production is possible. The bioconversions of lactose in milk ultrafiltrate were carried out either in a batch process or in a continuously operated enzyme membrane reactor (EMR) process. Both processes ran at an industrially relevant low temperature of 8°C to reduce undesirable microbial growth. The enzyme was reasonably active at the low process temperature because the CE originated from a mesophilic organism. An epilactose yield of 29.9% was achieved in the batch process within 28 h of operation time. In the continuous EMR process, the epilactose yield in the product stream was lower, at 18.5%. However, the enzyme productivity

Synthesis and Spectral Analysis of 3,4,5-trichloro-6-(dibenzo[d,f][1,3]diazepin-5-yl-[1,2]-benzoquinones

Directory of Open Access Journals (Sweden)

Mohsen A. M. Gomaa

2011-01-01

Full Text Available Reaction of N1,N2-di-(4-methoxyphenyl- or N1,N2-di-(4-hydroxyphenyl -amidines (1a-d with 3,4,5,6-tetrachloro-1,2-benzoquinone (2 in ethyl acetate at room temperature led to formation of new 3,4,5-trichloro-6-(2-hydroxy-6-methyldibenzo[d,f][1,3]diazepin-5-yl[1,2]-benzoquinones (3a-d in addition to N-aryl-N'-(6,7,8,9-tetrachloro-4-hydroxydibenzo-[1,4]dioxin-2-ylacetamidines (4a,b. The rational of formation of products 3a-d and 4a,b was discussed and structures were confirmed on the basis of elemental analysis and spectral data.

Crystal structure and Mössbauer spectroscopy of a new iron phosphate Mg{sub 2.88}Fe{sub 4.12}(PO{sub 4}){sub 6}

Energy Technology Data Exchange (ETDEWEB)

Saad, Y. [UR Matériaux Inorganiques, Faculté des Sciences, 5019 Monastir (Tunisia); Hidouri, M., E-mail: mourad_hidouri@yahoo.fr [UR Matériaux Inorganiques, Faculté des Sciences, 5019 Monastir (Tunisia); Álvarez-Serrano, I.; Veiga, M.L. [Departamento de Química Inorgánica I, Facultad de Ciencias Químicas, Universidad Complutense, 28040 Madrid (Spain); Wattiaux, A. [Institut de Chimie de la Matière Condensée de Bordeaux, CNRS, Université de Bordeaux I, 87 Avenue du Dr. A. Schweitzer, 33608 Pessac-Cedex (France); Amara, Mongi B. [UR Matériaux Inorganiques, Faculté des Sciences, 5019 Monastir (Tunisia)

2014-01-25

Highlights: • This study reports the synthesis and characterization of a new iron phosphate. • The cationic distribution is supported by a Mössbauer spectroscopy study. • The magnetic susceptibility results are discussed. -- Abstract: A new mixed valence iron phosphate Mg{sub 2.88}Fe{sub 4.12}(PO{sub 4}){sub 6} has been prepared as single crystals by the flux method and as a powder by solid state reaction and its crystal structure has been determined by X-ray diffraction. This compound crystallises in the triclinic system with space group P1{sup ¯} and a = 6.325(5) Å, b = 7.911(3) Å, c = 9.271(3) Å, α = 104.62(1)°, β = 108.41(1)° and γ = 101.24(1)° and Z = 1. Its structure is similar to that of the mineral howardevansite. It consists of Fe{sub 2}O{sub 10} bioctahedral units and MgO{sub 5} trigonal bipyramids sharing edges to form infinite zigzag chains. Such chains are linked to each other by MO{sub 6} (0.88 Mg{sup 2+} + 0.12 Fe{sup 2+}) octahedra and PO{sub 4} tetrahedra resulting in a 3D covalent framework. Magnetic measurements indicated two successive transitions at 46 K and 22 K. Mössbauer spectroscopy confirmed the mixed valence of iron and gave accurate information about its local environment.

Bi–Mn mixed metal organic oxide: A novel 3d-6p mixed metal coordination network

Energy Technology Data Exchange (ETDEWEB)

Shi, Fa-Nian, E-mail: fshi@ua.pt [School of Science, Shenyang University of Technology, 110870 Shenyang (China); Department of Chemistry, CICECO, University of Aveiro, 3810-193 Aveiro (Portugal); Rosa Silva, Ana [Department of Chemistry, CICECO, University of Aveiro, 3810-193 Aveiro (Portugal); Bian, Liang [Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi 830011, Xinjiang (China)

2015-05-15

A new terminology of metal organic oxide (MOO) was given a definition as a type of coordination polymers which possess the feature of inorganic connectivity between metals and the direct bonded atoms and show 1D, 2D or 3D inorganic sub-networks. One such compound was shown as an example. A 3d-6p (Mn–Bi. Named MOOMnBi) mixed metals coordination network has been synthesized via hydrothermal method. The new compound with the molecular formula of [MnBi{sub 2}O(1,3,5-BTC){sub 2}]{sub n} (1,3,5-BTC stands for benzene-1,3,5-tricarboxylate) was characterized via single crystal X-ray diffraction technique that revealed a very interesting 3-dimensional (3D) framework with Bi{sub 4}O{sub 2}(COO){sub 12} clusters which are further connected to Mn(COO){sub 6} fragments into a 2D MOO. The topology study indicates an unprecedented topological type with the net point group of (4{sup 13}.6{sup 2})(4{sup 13}.6{sup 8})(4{sup 16}.6{sup 5})(4{sup 18}.6{sup 10})(4{sup 22}.6{sup 14})(4{sup 3}) corresponding to 3,6,7,7,8,9-c hexa-nodal net. MOOMnBi shows catalytic activity in the synthesis of (E)-α,β-unsaturated ketones. - Graphical abstract: This metal organic framework (MOF) is the essence of a 2D metal organic oxide (MOO). - Highlights: • New concept of metal organic oxide (MOO) was defined and made difference from metal organic framework. • New MOO of MOOMnBi was synthesized by hydrothermal method. • Crystal structure of MOOMnBi was determined by single crystal X-ray analysis. • The catalytic activity of MOOMnBi was studied showing reusable after 2 cycles.

New greenish-yellow and yellowish-green emitting glass phosphors: Tb{sup 3+}/Eu{sup 3+} and Ce{sup 3+}/Tb{sup 3+}/Eu{sup 3+} in zinc phosphate glasses

Energy Technology Data Exchange (ETDEWEB)

Caldino, U., E-mail: cald@xanum.uam.mx [Departamento de Fisica, Universidad Autonoma Metropolitana-Iztapalapa, P.O. Box 55-534, 09340 Mexico D.F. (Mexico); Alvarez, E. [Departamento de Fisica, Universidad de Sonora (UNISON), Boulevard Luis Encinas y Rosales s/n, Hermosillo, Sonora 83000, Mexico (Mexico); Speghini, A. [Dipartimento di Biotecnologie, Universita di Verona, and INSTM, UdR Verona, Strada Le Grazie 15, I-37314 Verona (Italy); IFAC CNR, Nello Carrara Institute of Applied Physics, MDF Lab, I-50019 Sesto Fiorentino, FI (Italy); Bettinelli, M. [Dipartimento di Biotecnologie, Universita di Verona, and INSTM, UdR Verona, Strada Le Grazie 15, I-37314 Verona (Italy)

2013-03-15

A spectroscopic investigation of zinc phosphate glasses activated with Eu{sup 3+}, Tb{sup 3+}/Eu{sup 3+} and Ce{sup 3+}/Tb{sup 3+}/Eu{sup 3+} ions is performed through photoluminescence spectra and decay time measurements. Greenish-yellow light emission, with x=0.42 and y=0.50 CIE1931 chromaticity coordinates, is obtained in the 5.0% Tb(PO{sub 3}){sub 3}-2.0% Eu(PO{sub 3}){sub 3} codoped zinc phosphate glass upon Tb{sup 3+} excitation at 340 nm. Such greenish-yellow luminescence is generated mainly by the {sup 5}D{sub 4}{yields}{sup 7}F{sub 6,5} and {sup 5}D{sub 0}{yields}{sup 7}F{sub 1,2} emissions of Tb{sup 3+} and Eu{sup 3+}, respectively, europium being sensitized by terbium through a non-radiative energy transfer. By codoping with 0.1 Ce(PO{sub 3}){sub 3} in addition to Tb{sup 3+}/Eu{sup 3+} yellowish-green light emission with CIE1931 chromaticity coordinates, x=0.33 and y=0.48, is achieved through non-radiative energy transfer from Ce{sup 3+} to Tb{sup 3+} and from Ce{sup 3+} via Tb{sup 3+} to Eu{sup 3+} upon 280 nm excitation (peak emission wavelength of AlGaN-based LEDs). - Highlights: Black-Right-Pointing-Pointer Zn(PO{sub 3}){sub 2} glasses are optically activated with Tb{sup 3+}/Eu{sup 3+} (ZPO5Tb2Eu) and Ce{sup 3+}/Eu{sup 3+}/Tb{sup 3+} (ZPOCe5Tb2Eu). Black-Right-Pointing-Pointer Non-radiative energy transfer Tb{sup 3+}{yields}Eu{sup 3+} takes place in ZPO5Tb2Eu. Black-Right-Pointing-Pointer Greenish-yellow light is generated by ZPO5Tb2Eu pumped with 340 nm-UV light. Black-Right-Pointing-Pointer Non-radiative energy transfer Ce{sup 3+}{yields}Tb{sup 3+} and Ce{sup 3+}{yields}Eu{sup 3+} via Tb{sup 3+} takes place in ZPOCe5Tb2Eu. Black-Right-Pointing-Pointer Yellowish-green light is generated by ZPOCe5Tb2Eu pumped with 280 nm-UV light (AlGaN-LEDs).

Biochemical and cytochemical evaluation of heterozygote individuals with glucose-6-phosphate dehydrogenase deficiency

NARCIS (Netherlands)

Gurbuz, Nilgun; Aksu, Tevfik Aslan; van Noorden, Cornelis J. F.

2005-01-01

The aim of this study was to diagnose heterozygous glucose-6-phosphate dehydrogenase (G6PD) deficient females by an inexpensive cytochemical G6PD staining method that is easy to perform, allowing diagnosis of G6PD deficiency without cumbersome genetic analysis. Three subject groups were included in

Praseodymium ion doped phosphate glasses for integrated broadband ion-exchanged waveguide amplifier

Energy Technology Data Exchange (ETDEWEB)

Shen, L.F. [School of Textile and Material Engineering, Dalian Polytechnic University, Dalian 116034 (China); Department of Electronic Engineering, City University of Hong Kong, Kowloon, Hong Kong (China); Chen, B.J. [Department of Electronic Engineering, City University of Hong Kong, Kowloon, Hong Kong (China); Lin, H., E-mail: lhai8686@yahoo.com [School of Textile and Material Engineering, Dalian Polytechnic University, Dalian 116034 (China); Department of Electronic Engineering, City University of Hong Kong, Kowloon, Hong Kong (China); Pun, E.Y.B. [Department of Electronic Engineering, City University of Hong Kong, Kowloon, Hong Kong (China)

2015-02-15

Highlights: • Effective near-infrared emission (1380-1525 nm) is observed in Pr{sup 3+}-doped phosphate glasses. • Effective bandwidth of {sup 1}D{sub 2} → {sup 1}G{sub 4} transition emission is obtained to be 124 nm. • Channel waveguides have been fabricated by K{sup +}-Na{sup +} ion-exchange method. • Pr{sup 3+}-doped phosphate glasses are promising in developing integrated broadband waveguide amplifier. - Abstract: Effective near-infrared emission covering the fifth optical telecommunication window (1380-1525 nm) has been observed in Pr{sup 3+}-doped phosphate (NMAP) glasses. Judd-Ofelt parameters Ω{sub 2} (6.38 × 10{sup −20} cm{sup 2}), Ω{sub 4} (20.30 × 10{sup −20} cm{sup 2}) and Ω{sub 6} (0.40 × 10{sup −20} cm{sup 2}) indicate a high inversion asymmetrical and strong covalent environment in the optical glasses. The effective bandwidth (Δλ{sub eff}) of the corresponding {sup 1}D{sub 2} → {sup 1}G{sub 4} transition emission is obtained to be 124 nm, and the maximum stimulated emission cross-section (σ{sub em-max}) at 1468 nm is derived to be 1.14 × 10{sup −20} cm{sup 2}. Channel waveguide was fabricated successfully by K{sup +}-Na{sup +} ion-exchange method with mode field diameter of 8.8 μm in the horizontal direction and 6.7 μm in the vertical direction. Broad effective bandwidth, large emission cross-section and perfect thermal ion-exchangeability indicate that Pr{sup 3+}-doped NMAP phosphate glasses are promising in developing integrated broadband waveguide amplifier, especially operating at E- and S-bands which belong to the fifth optical telecommunication window.

Synthesis and physico-chemical properties of (R,S)-6-ditrideuteriomethylamino-4,4-diphenylheptan-3-one hydrochloride (methadone-d6)

International Nuclear Information System (INIS)

Gerardy, B.M.; Poupaert, J.H.; Vandervorst, D.; Dumont, P.; Declerq, J.-P.; Meerssche, M. van; Portoghese, P.S.

1985-01-01

A reaction sequence is described to synthesize (R,S)-6-ditrideuteriomethylamino-4,4-diphenylheptan-3-one hydrochloride (methado-ne-d 6 .HC1) in 10.5% overall yield starting from dimethylamine-d 6 hydrochloride. While methadone-d 6 .HC1 had rather similar physicochemical properties compared to methadone.HC1 in the solid phase, a divergent behaviour was observed in solution (pKa, chromatographic and 13 C-NMR data). A higher basicity along with a more important hydrophilicity were observed for the d 6 -derivative. A 13 C-NMR study showed significant differences in the 13 C chemical shifts, which were attributed in part to the intrinsic nature of D itself and in part to a conformational perturbation. The longer duration of antinociceptive action, along with higher tsub(1/2) and clearance, and the depression of the metabolic N-demethylation process were the only biological properties modified by the deuteration. (author)

Reagentless phosphate ion sensor system for environmental monitoring

Energy Technology Data Exchange (ETDEWEB)

Suzuki, M.; Kurata, H.; Inoue, Y.; Shin, H. [Kyushu Institute of Technology, Fukuoka (Japan). Faculty of computer Science and Systems; Kubo, I. [Soka University, Tokyo (Japan). Faculty of Engineering; Nakamura, H.; Ikebukuro, K.; Karube, I. [The University of Tokyo, Tokyo (Japan). Research Center for Advanced Science and Technology

1998-06-05

Phosphate ion sensor system using an electrochemical detector was developed by the use of recombinant pyruvate oxidase (PyOD) from Lactobacillus plantarum, which needs no addition of thiamine pyrophosphate and flavin adenine dinucleotide for reaction. This system could detect 2 nM hydrogen peroxide. Response time for phosphate ion was 80 s and total measurement time for one sample was 3 min. Citrate buffer solution (pH 6.3) was most suitable for the measurement and optimum flow rate was 0.6 ml/min. Under these optimum conditions minimum detection limit of phosphate ion was 15 nM, which was enough for the determination of phosphate ion in dam-lake. 6 refs., 5 figs., 1 tab.

Aminopropyl-functionalized mesoporous carbon (APTMS-CMK-3) as effective phosphate adsorbent

Science.gov (United States)

Yang, Yanju; Wang, Juanjuan; Qian, Xiaoqing; Shan, Yuhua; Zhang, Haipeng

2018-01-01

Excess phosphate discharge into water bodies can lead to severe eutrophication. Adsorption has been considered as one of the most effective approaches for phosphate removal and recovery. A new aminopropyl-functionalized mesoporous carbon CMK-3 (denoted as APTMS-CMK-3) was prepared and the materials were used as adsorbents for the removal of phosphate in water. The structure, functional groups and surface charge of the materials were characterized by X-ray powder diffraction, transmission electron microscope, N2 adsorption-desorption, elemental analysis, Fourier transform infrared spectra, X-ray photoelectron spectroscopy and zeta potential measurements. The effects of contact time, initial phosphate concentration, solution pH, coexisting anions and dissolved humic acid were studied. The adsorption capacity of APTMS-CMK-3 was 38.09 mg g-1 at the equilibrium concentration of 49.06 mg L-1, and the adsorption data were well fitted with the Freundlich model. As for the reuse of APTMS-CMK-3, a relatively stable adsorption performance was observed after five adsorption-desorption cycles. Therefore, the way of grafting aminopropyl groups on the CMK-3 efficiently enhanced the capability for phosphate adsorption, indicating that it could be used as potential adsorbents for the removal of phosphate in water.

Concentration dependent spectroscopic properties of Dy{sup 3+} ions doped boro-phosphate glasses

Energy Technology Data Exchange (ETDEWEB)

Mariyappan, M.; Marimuthu, K., E-mail: mari-ram2000@yahoo.com [Department of Physics, Gandhigram Rural Institute - Deemed University, Gandhigram – 624 302 (India)

2016-05-23

Dy{sup 3+} ions doped boro-phosphate glasses have been synthesized by melt quenching method and characterized through FTIR, absorption and luminescence spectral measurements. The presence of various stretching and bending vibrations of different borate and phosphate groups were identified from the FTIR spectra. In order to examine the electronic band structure of the studied glasses, Optical energy gap (E{sub opt}) and Urbach energy (ΔE) values were estimated from the absorption spectra. The Judd-Ofelt (JO) intensity parameters were calculated to examine the symmetry of the ligand environment around the Dy{sup 3+} ions site. The emission spectra exhibit two intense emission bands at around 482 nm (blue) and 574 nm (yellow) corresponding to the {sup 4}F{sub 9/2}→{sup 6}H{sub 15/2} and {sup 4}F{sub 9/2}→{sup 6}H{sub 13/2} transitions respectively. The emission spectra were characterized through Commission International d’Eclairage (CIE) 1931 chromaticity diagram to explore its suitability for WLED applications.

Convenient large-scale synthesis of D-glucaro-1,4:6,3-dilactone.

Science.gov (United States)

Gehret, Troy C; Frobese, A Stephen; Zerbe, James S; Chenault, H Keith

2009-11-06

Calcium D-glucarate was converted into D-glucaro-1,4:6,3-dilactone on 32-g, 1-kg, and 22-kg scale, using azeotropic distillation with methyl isobutyl ketone to drive the dehydration. The crystalline product was > or = 99.5% pure by GC and NMR, and overall yield was as high as 72%.

A study of luminescence from Eu{sup 3+}, Ce{sup 3+}, Tb{sup 3+} and Ce{sup 3+}/Tb{sup 3+} in new potassium gadolinium phosphate K{sub 3}Gd{sub 5}(PO{sub 4}){sub 6}

Energy Technology Data Exchange (ETDEWEB)

Meng, Fangui; Zhang, Hongzhi [School of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha 410004 (China); Chen, Cuili; Kim, Sun Il [Department of Physics and Interdisciplinary Program of Biomedical, Mechanical & Electrical Engineering, Pukyong National University, Busan 608-737 (Korea, Republic of); Seo, Hyo Jin, E-mail: hjseo@pknu.ac.kr [Department of Physics and Interdisciplinary Program of Biomedical, Mechanical & Electrical Engineering, Pukyong National University, Busan 608-737 (Korea, Republic of); Zhang, Xinmin, E-mail: xmzhuga@163.com [School of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha 410004 (China)

2016-06-25

New potassium gadolinium phosphate [K{sub 3}Gd{sub 5}(PO{sub 4}){sub 6}] doped with Eu{sup 3+}, Ce{sup 3+}, Tb{sup 3+} and co-doped with Ce{sup 3+} and Tb{sup 3+} phosphors were prepared by high temperature solid state synthesis. Phase purity of the powders was checked by X-ray powder diffraction. Luminescence and excitation spectra of samples were reported. In particular, the interaction mechanism between Eu{sup 3+} ions was investigated in terms of the Inokuti–Hirayama model; it was found that the interactions between Eu{sup 3+} can be assigned to dipole–dipole interaction. K{sub 3}Gd{sub 5}(PO{sub 4}){sub 6}:Eu{sup 3+} could act as a candidate for solid state lighting due to its strong absorption band in the near-UV region (350–400 nm). The energy transfer from Ce{sup 3+} to Tb{sup 3+} was confirmed and the mechanism was studied using Dexter's theory; it is concluded that electric dipole–dipole interaction predominates in the energy transfer process from Ce{sup 3+} to Tb{sup 3+} in the K{sub 3}Gd{sub 5}(PO{sub 4}){sub 6} host. The energy transfer efficiency and critical distance were also investigated. - Highlights: • Optical properties of K{sub 3}Gd{sub 5}(PO{sub 4}){sub 6}:RE{sup 3+} are investigated for the first time. • The interaction mechanism between Eu{sup 3+} ions is attributed to dipole–dipole type. • K{sub 3}Eu{sub 5}(PO{sub 4}){sub 6} is a candidate phosphor for application to solid state lighting. • There exists an efficient energy transfer from Ce{sup 3+} to Tb{sup 3+} (η is up to 95%). • The mechanism of energy transfer process is electric dipole–dipole interaction.

Recognition of mannose 6-phosphate ligands by dystrophic rat retinal pigment epithelium

International Nuclear Information System (INIS)

Tarnowski, B.; Shepherd, V.; McLaughlin, B.

1986-01-01

Retinal pigment epithelium (RPE) phagocytize discarded rod outer segments (ROS) during normal eye function. In the dystrophic rat, an animal model for retinitis pigmentosa in humans, ROS phagocytosis is defective. Dystrophic RPE can phagocytize particles other than ROS, suggesting that the defect may be in the RPE phagocytic recognition. They are currently investigating the recognition markers on RPE in dystrophic rats. In studies using ligand-coated latex beads, no uptake of mannose-coated beads was found in dystrophic rat RPE. They found that dystrophic RPE could specifically phagocytize phosphomannan-coated beads. Studies were begun to examine the presence and function of a phosphomannan receptor (PMR) on dystrophic RPE. α-Mannosidase, isolated from D. discoideum has been shown to be an efficient ligand for the PMR in fibroblasts and macrophages. It is also recognized by the macrophage mannose receptor. Dystrophic rat RPE and retina explants were placed in culture dishes (5-7/well). 125 I-Labelled α-mannosidase was added to each well in the presence or absence of 10 mM mannose 6-phosphate (M6P) or yeast mannan (lmg/ml). Explants were incubated at 37 0 for 2 hr., washed and bound 125 I-mannosidase quantitated. Approximately 2-3% of total counts added were bound to the RPE via a M6P-inhibitable recognition process. The binding to RPE was not blocked by mannan. No mannan or M6P-specific binding was found in retina explants. These results support the findings of specific uptake of phosphomannan-coated beads and demonstrate the presence of a specific PMR on dystrophic RPE phagocytic membranes

Modulation of nuclear T3 binding by T3 in a human hepatocyte cell-line (Chang-liver) - T3 stimulation of cell growth but not of malic enzyme, glucose-6-phosphatdehydrogenase or 6-phosphogluconate-dehydrogenase

DEFF Research Database (Denmark)

Matzen, L E; Kristensen, S R; Kvetny, J

1991-01-01

The T3 modulation of nuclear T3 binding (NBT3), the T3 effect on cell growth, and the T3 and insulin effects on malic enzyme (ME), glucose-6-phosphat-dehydrogenase (G6PD) and 6-phosphogluconat-dehydrogenase (G6PD) were studied in a human hepatocyte cell-line (Chang-liver). T3 was bound to a high ...

Glucose-6-phosphate dehydrogenase activity decreases during storage of leukoreduced red blood cells

NARCIS (Netherlands)

Peters, Anna L.; van Bruggen, Robin; de Korte, Dirk; van Noorden, Cornelis J. F.; Vlaar, Alexander P. J.

2016-01-01

During storage, the activity of the red blood cell (RBC) antioxidant system decreases. Glucose-6-phosphate dehydrogenase (G6PD) is essential for protection against oxidative stress by producing NADPH. G6PD function of RBC transfusion products is reported to remain stable during storage, but activity

Characterization of D-myo-inositol 3-phosphate synthase gene expression in two soybean low phytate mutants

International Nuclear Information System (INIS)

Yuan Fengjie; Dong Dekun; Li Baiquan; Yu Xiaomin; Fu Xujun; Zhu Danhua; Zhu Shenlong; Yang Qinghua

2013-01-01

1D-myo-inositol 3-phosphate synthase (MIPS) gene plays a significant role in phytic acid biosynthesis. In this study, we used two low phytic acid mutants Gm-lpa-TW-1, Gm-lpa-ZC-2 and their respective wild type parents Taiwan75 and Zhechun No.3 to analyze the expression pattern and characterization of MIPS1 gene. The results showed that there was a common expression pattern of MIPS1 in soybean developing seeds. Expression was weak as detected by RT-PCR in initial stage, increased in the following stages, and the peak expression was appeared in 22 day after flowering (DAF). The expression of MIPS1 gene of non-seed tissues in mutant Gm-lpa-TW-1 and its wildtype Taiwan75 was very weak. In the developing seeds, the MIPS1 expression by qRT-PCR revealed a significant reduction in 22 DAF in mutant Gm-lpa-TW-1 as compared with the wildtype. Similarly, the expression of MIPS1 gene in non-seed tissue of Zhenchun No.3 and Gm-lpa-ZC-2 was very weak. However, stronger expression in developing seeds of the mutant Gm-lpa-ZC-2 than Zhechun No.3 was found. We concluded that the MIPS1 gene expression in the developing seed exhibited an up-regulation pattern in mutant Gm-lpa-ZC-2, but a down-regulation pattern in the mutant Gm-lpa-TW-1. (authors)

The 4p-5d, 6d and 4p-6s, 7s transitions of Mo IX

International Nuclear Information System (INIS)

Khatoon, S.; Chaghtai, M.S.Z.; Rahimullah, K.

1979-01-01

The transitions 4p-5d, 6d and 4p-6s, 7s have been studied for the first time in Mo IX. The authors have identified 42 4p-5d, 36 4p-6d, 22 4p-6s and 22 4p-7s transitions, establishing 16 4p 3 5d, 14 4p 3 6d and all the ten 4p 3 6s, 7s levels of the spectrum concerned. The ionization energy is estimated to be (1 323 700 +- 700)cm -1 or (164.11 +- 0.09)eV. The spectrum was recorded in sliding and open spark discharges with a 5 m grazing incidence spectrograph of Lund University (Sweden) from about 40 A to 440 A. (Auth.)

Application of 6D Building Information Model (6D BIM) for Business-storage Building in Slovenia

Science.gov (United States)

Pučko, Zoran; Vincek, Dražen; Štrukelj, Andrej; Šuman, Nataša

2017-10-01

The aim of this paper is to present an application of 6D building information modelling (6D BIM) on a real business-storage building in Slovenia. First, features of building maintenance in general are described according to the current Slovenian legislation, and also a general principle of BIM is given. After that, step-by-step activities for modelling 6D BIM are exposed, namely from Element list for maintenance, determination of their lifetime and service measures, cost analysing and time analysing to 6D BIM modelling. The presented 6D BIM model is designed in a unique way in which cost analysis is performed as 5D BIM model with linked data to use BIM Construction Project Management Software (Vico Office), integrated with 3D BIM model, whereas time analysis as 4D BIM model is carried out as non-linked data with the help of Excel (without connection to 3D BIM model). The paper is intended to serve as a guide to the building owners to prepare 6D BIM and to provide an insight into the relevant dynamic information about intervals and costs for execution of maintenance works in the whole building lifecycle.

P contribution derived from phosphate solubilizing microorganism activity, rock phosphate and SP-36 determination by isotope "3"2P technique

International Nuclear Information System (INIS)

Anggi Nico Flatian; Iswandi Anas; Atang Sutandi; Ishak

2016-01-01

The "3"2P isotope technique has been used to trace P nutrients in the soil and soil-plant systems. The use of the isotope "3"2P has made it possible to differentiate the P contribution derived from phosphate solubilizing microorganism activity and the fertilizer P in the soil. The aims of the study were to obtain the quantitative data of P contribution derived from phosphate-solubilizing microorganism activity (Aspergillus niger and Burkholderia cepacia), rock phosphate and SP-36 through P uptake by the plants using isotope "3"2P technique and also to study the effects on growth and production of corn plants. The results were showed that phosphate-solubilizing microorganism, rock phosphate and SP-36 was produced specific activity ("3"2P) lower than control. The results were indicated that all treatments could contribute P for the plants. The lower specific activity was caused by supply P from rock phosphate and SP-36, and also was caused by solubilized of unavailable "3"1P from PSM activity, which decreased specific activity on labeled soil. The combination of phosphate-solubilizing microorganism and SP-36 treatments produced the highest P contribution, significantly higher than control and SP-36 only. Phosphate derived from combination of microorganism and SP-36 treatments ranging from 56.06% - 68.54% after 50 days planting, after 35 days planting, 51.96% - 59.65% on stover, 46.33% - 47.70% on grain and 53.02% - 59.87% on corn cob. In addition, the treatments could significantly support the plant growth and yield. It is expressed by increased number of leave at 35 days after planting, dry weight of leave at 35 days after planting and dry weight of grain. (author)

Co-sequestration of Zn(II) and phosphate by γ-Al{sub 2}O{sub 3}: From macroscopic to microscopic investigation

Energy Technology Data Exchange (ETDEWEB)

Ren, Xuemei [School of Environment and Chemical Engineering, North China Electric Power University, Beijing 102206 (China); Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, 230031, Hefei (China); Tan, Xiaoli [Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, 230031, Hefei (China); Hayat, Tasawar [Department of Mathematics, Quaid-I-Azam University, Islamabad 44000 (Pakistan); NAAM Research Group, Faculty of Science, King Abdulaziz University, Jeddah 21589 (Saudi Arabia); Alsaedi, Ahmed [NAAM Research Group, Faculty of Science, King Abdulaziz University, Jeddah 21589 (Saudi Arabia); Wang, Xiangke, E-mail: xkwang@ipp.ac.cn [School of Environment and Chemical Engineering, North China Electric Power University, Beijing 102206 (China); NAAM Research Group, Faculty of Science, King Abdulaziz University, Jeddah 21589 (Saudi Arabia); Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions (China)

2015-10-30

Highlights: • How the Zn and phosphate behave in each other’s presence is elucidated. • Surface speciation of Zn(II) is affected by the presence of phosphate. • Combining macroscopic study with EXAFS can determine the Zn(II) surface speciation. • The enhanced Zn(II) sorption is mainly due to ternary surface complexation at 0.19 mmol P/L and pH 6.5. • Phosphate ions prevent the formation of an Zn–Al LDH phase at pH 8.0. - Abstract: Little information is available concerning co-sorbing oxyanion and metal contaminants in the environment, yet in most metal-contaminated areas, co-contamination by phosphate is common. In this study, the mutual effects of phosphate and Zn(II) on their interaction with γ-Al{sub 2}O{sub 3} are investigated by batch experiments and X-ray absorption fine structure spectroscopy (XAFS) technique. The results show that the co-sorption of phosphate on γ-Al{sub 2}O{sub 3} modifies both the extent of Zn(II) sorption and the local atomic structures of sorbed Zn(II) ions. Multiple mechanisms are involved in Zn(II) retention in the presence of phosphate, including electrostatic interaction, binary and ternary surface complexation, and the formation of Zn(II)-phosphate polynuclear complexes. At pH 6.5, type III ternary surface complexation occurs concurrently with binary Zn-alumina surface complexation at low phosphate concentrations, whereas the formation of type III ternary surface complexes is promoted as the phosphate concentration increases. With further increasing phosphate concentration, Zn(II)-phosphate polynuclear complexes are formed. At pH 8.0, Zn dominantly forms type III ternary surface complexes in the presence of phosphate. The results of this study indicate the variability of Zn complexation on oxide surface and the importance of combining macroscopic observations with XAFS capable of determining metal complex formation mechanism for ternary system.

Icterícia neonatal e deficiência de glicose-6-fosfato desidrogenase Neonatal jaundice and glucose-6-phosphate dehydrogenase

Directory of Open Access Journals (Sweden)

Amauri Antiquera Leite

2010-01-01

Full Text Available A deficiência de glicose-6-fosfato desidrogenase em neonatos pode ser a responsável pela icterícia neonatal. Este comentário científico é decorrente do relato sobre o tema publicado neste fascículo e que preocupa diversos autores de outros países em relação às complicações em neonatos de hiperbilirrubinemia, existindo inclusive proposições de alguns autores em incluir o teste para identificar a deficiência de glicose-6-fosfato desidrogenase nos recém-nascidos.Glucose-6-phosphate dehydrogenase in newborn babies may be responsible for neonatal jaundice. There is a concern of many authors from other countries in respect to complications in neonates with hyperbilirubinemia; some authors even propose screening for glucose-6-phosphate dehydrogenase deficiency in newborn babies. A scientific report on this subject is published in this issue.

Synthesis of methyl 3-O-{alpha}-d-glucopyranosyl-C{sub 6}{sup 14}-{beta}-d-xylopyranoside and methyl 2-O-{alpha}-d-Glucopyranosyl-C{sub 6}{sup 14}-l-noviopyranoside; Synthese de methyl-3-O-alpha-D-glucopyranosyl-C{sup 14}-beta-D-xylophranoside et methyl-2-O-alpha-D-glucopyranosyl-C{sub 6}{sup 14}-L-noviopyranoside; Sintez metil-3-O-{alpha}-D-glyukopiranozila-C{sub 6}{sup 14}-{beta}-D-ksilopiranozid i metil 2-O-{alpha}-D-glyukopiranozil-C{sub 6}{sup 14}-L-noviopiranozid; Sintesis de la metil 3-O-{alpha}-D-glucopiranosil-{sup 14}C{sub 6}-{beta}-D-xilopiranosido y de la metil 2-O-{alpha}-D-glucopiranosil-{sup 14}C{sub 6}-L-noviopiranosido

Energy Technology Data Exchange (ETDEWEB)

Barker, S A; Keith, M C; Stacey, M; Stroud, D B.E. [Chemistry Department, University of Birmingham (United Kingdom)

1962-03-15

Where difficulty is encountered in the chemical synthesis of a disaccharide glycoside labelled with C{sub 6}{sup 14} specifically in only one of its sugar moieties it is often convenient to resort to a synthesis catalysed by microbial transglycosylases. Two examples of the application of this technique are reported; the syntheses: Maltose-C{sub 12}{sup 14} + Methyl {beta}-d-xylopyranoside Penicillium lilacinum/transglucosylase {yields} Methyl 3-0-{alpha}-d-Glucopyranosyl-C{sub 6}{sup 14}-{beta}-d-xylopyranoside (I) + Glucose-C{sub 6}{sup 14} Maltose-C{sub 12}{sup 14} + Methyl l-noviopyranoside Fusarium moniliforme/transglucosylase Methyl-2-0-{alpha}d-Glucopyranosyl-C{sub 6}{sup 14}-l-noviopyranoside (II) + Glucose-C{sub 6}{sup 14}. In such syntheses, it is predictable that the anomeric character of the glycosidic linkage of the donor disaccharide will be retained in the disaccharide synthezised and that the glycosyl residue transferred will be attached, through its reducing group, to the receptor monosaccharide glycoside. By using either a C{sup 14}-labelled donor disaccharide or a C{sup 14}-labelled receptor glycoside, a disaccharide can be synthesized with only one of its sugar moieties labelled. In the synthesis of II the only hydroxyl group free in the receptor methyl novioside is on C{sub 2} and the transferred glucosyl residue can only be attached here. In the synthesis of I the methyl xyloside has free hydroxyls on C{sub 2}, C{sub 3} and C{sub 4} and the microbial enzyme has been found to transfer the glucosyl residue specifically to the hydroxyl on C{sub 3}. The structures of I and I I have been established by the results of elemental analysis, optical rotation, infrared spectra together with an examination of the products of acid hydrolysis and periodate oxidation. (author) [French] Lorsqu'on se heurte a des difficultes dans la synthese chimique d'un glucoside de disaccharide marque au carbone-14 specifiquement dans un seul des deux sucres qui le

Preparation of calcium phosphate paste

International Nuclear Information System (INIS)

Mohd Reusmaazran Yusof; Norzita Yaacob; Idris Besar; Che Seman Mahmood; Rusnah Mustafa

2010-01-01

Calcium phosphate paste were prepared by mixing between calcium sodium potassium phosphate, Ca 2 NaK (PO 4 ) 2 (CSPP) and monocalcium phosphate monohydrate, Ca(H 2 PO 4 ) 2 .H 2 O (MCPM). CSPP were obtained by reaction between calcium hydrogen phosphate (CaHPO 4 ), potassium carbonate (K 2 CO 3 ) and sodium carbonate (Na 2 CO 3 ) in solid state sintering process followed by quenching in air at 1000 degree Celsius. The paste was aging in simulated body fluid (SBF) for 0.5, 1, 3, 6, 12, 24, 48 hrs, 3, 7 and 14 days. The morphological investigation indicated the formation of apatite crystal were first growth after 24 hours. The obvious growth of apatite crystal was shown at 3 days. The obvious growth of apatite crystal was shown in 7 and 14 days indicated the prediction of paste would have rapid reaction with bone after implantation. (author)

Overexpression, crystallization and preliminary X-ray crystallographic analysis of erythronate-4-phosphate dehydrogenase from Pseudomonas aeruginosa.

Science.gov (United States)

Ha, Jun Yong; Lee, Ji Hyun; Kim, Kyoung Hoon; Kim, Do Jin; Lee, Hyung Ho; Kim, Hye-Kyung; Yoon, Hye-Jin; Suh, Se Won

2006-02-01

The enzyme erythronate-4-phosphate dehydrogenase catalyses the conversion of erythronate-4-phosphate to 3-hydroxy-4-phospho-hydroxy-alpha-ketobutyrate. It belongs to the D-isomer-specific 2-hydroxyacid dehydrogenase family. It is essential for de novo biosynthesis of vitamin B6 (pyridoxine). Erythronate-4-phosphate dehydrogenase from Pseudomonas aeruginosa, a homodimeric enzyme consisting of two identical 380-residue subunits, has been overexpressed in Escherichia coli with a C-terminal purification tag and crystallized at 297 K using 0.7 M ammonium dihydrogen phosphate, 0.4 M ammonium tartrate, 0.1 M sodium citrate pH 5.6 and 10 mM cupric chloride. X-ray diffraction data were collected to 2.20 A from a crystal grown in the presence of NADH. The crystals belong to the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 84.77, b = 101.28, c = 142.58 A. A dimeric molecule is present in the asymmetric unit, giving a crystal volume per protein weight (VM) of 3.64 A3 Da(-1) and a solvent content of 66%.

Expression, purification, crystallization and preliminary X-ray analysis of an NADP-dependent glyceraldehyde-3-phosphate dehydrogenase from Helicobacter pylori

Energy Technology Data Exchange (ETDEWEB)

Elliott, Paul R.; Evans, Daniel; Greenwood, Jacqueline A.; Moody, Peter C. E., E-mail: pcem1@leicester.ac.uk [Henry Wellcome Laboratories for Structural Biology, Department of Biochemistry, University of Leicester, Leicester LE1 9HN (United Kingdom)

2008-08-01

Glyceraldehyde-3-phosphate dehydrogenase A has been cloned, expressed and purified. Apoprotein crystals have been grown which diffracted to 1.75 Å resolution and belonged to space group P2{sub 1}; holo crystals were grown in the presence of NADP, diffracted to 2.6 Å resolution and belonged to space group P3{sub 2}. The classical glycolytic pathway contains an NAD-dependent glyceraldehyde-3-phosphate dehydrogenase, with NADP-dependent forms reserved for photosynthetic organisms and archaea. Here, the cloning, expression, purification, crystallization and preliminary X-ray analysis of an NADP-dependent glyceraldehyde-3-phosphate dehydrogenase from Helicobacter pylori is reported; crystals of the protein were grown both in the presence and the absence of NADP.

Expression, purification, crystallization and preliminary X-ray analysis of an NADP-dependent glyceraldehyde-3-phosphate dehydrogenase from Helicobacter pylori

International Nuclear Information System (INIS)

Elliott, Paul R.; Evans, Daniel; Greenwood, Jacqueline A.; Moody, Peter C. E.

2008-01-01

Glyceraldehyde-3-phosphate dehydrogenase A has been cloned, expressed and purified. Apoprotein crystals have been grown which diffracted to 1.75 Å resolution and belonged to space group P2 1 ; holo crystals were grown in the presence of NADP, diffracted to 2.6 Å resolution and belonged to space group P3 2 . The classical glycolytic pathway contains an NAD-dependent glyceraldehyde-3-phosphate dehydrogenase, with NADP-dependent forms reserved for photosynthetic organisms and archaea. Here, the cloning, expression, purification, crystallization and preliminary X-ray analysis of an NADP-dependent glyceraldehyde-3-phosphate dehydrogenase from Helicobacter pylori is reported; crystals of the protein were grown both in the presence and the absence of NADP

Identification of the transition arrays 3d74s-3d74p in Br X and 3d64s-3d64p in Br XI

International Nuclear Information System (INIS)

Zeng, X.T.; Jupen, C.; Bengtsson, P.; Engstroem, L.; Westerlind, M.; Martinson, I.

1991-01-01

We report a beam-foil study of multiply ionized bromine in the region 400-1300A, performed with 6 and 8 MeV Br ions from a tandem accelerator. At these energies transitions belonging to Fe-like Br X and Mn-like Br XI are expected to be prominent. We have identified 31 lines as 3d 7 4s-3d 7 4p transitions in Br X, from which 16 levels of the previously unknown 3d 7 4s configuration could be established. We have also added 6 new 3d 7 4p levels to the 99 previously known. For Br XI we have classified 9 lines as 3d 6 4s-3d 6 4p combinations. The line identifications have been corroborated by isoelectronic comparisons and theoretical calculations using the superposition-of-configurations technique. (orig.)

Fluorometric determination of free glucose and glucose 6-phosphate in cows' milk and other opaque matrices

DEFF Research Database (Denmark)

Larsen, Torben

2015-01-01

Analyses of free glucose and glucose 6-phosphate in milk have until now been dependent upon several time consuming and troublesome procedures. This has limited investigations in the area. The present article presents a new, reliable, analytical procedure, based on enzymatic degradation and fluoro......Analyses of free glucose and glucose 6-phosphate in milk have until now been dependent upon several time consuming and troublesome procedures. This has limited investigations in the area. The present article presents a new, reliable, analytical procedure, based on enzymatic degradation...... and fluorometric detection. Standards and control materials were based on milk that was stripped of intrinsic glucose and glucose 6-phosphate in order to obtain standards and samples based on the same matrix. The analysis works without pre-treatment of the samples, e.g. without centrifugation and precipitation...

Analysis of trehalose-6-phosphate control over carbon allocation and growth in plants

NARCIS (Netherlands)

Aghdasi, M.

2007-01-01

Trehalose is the non-reducing alpha-alpha-1, 1-linked glucose disaccharide. The biosynthesic precursor of trehalose, trehalose-6-phosphate (T6P), is essential for plant development, growth, carbon utilization and alters photosynthetic capacity but its mode of action is not underestood. This thesis

Erbium-doped phosphate glass waveguide on silicon with 4.1 dB/cm gain at 1.535 µm

Science.gov (United States)

Yan, Y. C.; Faber, A. J.; de Waal, H.; Kik, P. G.; Polman, A.

1997-11-01

Erbium-doped multicomponent phosphate glass waveguides were deposited by rf sputtering techniques. The Er concentration was 5.3×1020cm-3. By pumping the waveguide at 980 nm with a power of ˜21 mW, a net optical gain of 4.1 dB at 1.535 μm was achieved. This high gain per unit length at low pump power could be achieved because the Er-Er cooperative upconversion interactions in this heavily Er-doped phosphate glass are very weak [the upconversion coefficient is (2.0±0.5)×10-18 cm3/s], presumably due to the homogeneous distribution of Er in the glass and due to the high optical mode confinement in the waveguide which leads to high pump power density at low pump power.

Hexose-6-phosphate dehydrogenase contributes to skeletal muscle homeostasis independent of 11β-hydroxysteroid dehydrogenase type 1.

LENUS (Irish Health Repository)

Semjonous, Nina M

2011-01-01

Glucose-6-phosphate (G6P) metabolism by the enzyme hexose-6-phosphate dehydrogenase (H6PDH) within the sarcoplasmic reticulum lumen generates nicotinamide adenine dinucleotide phosphate (reduced) to provide the redox potential for the enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) to activate glucocorticoid (GC). H6PDH knockout (KO) mice have a switch in 11β-HSD1 activity, resulting in GC inactivation and hypothalamic-pituitary-adrenal axis activation. Importantly, H6PDHKO mice develop a type II fiber myopathy with abnormalities in glucose metabolism and activation of the unfolded protein response (UPR). GCs play important roles in muscle physiology, and therefore, we have examined the importance of 11β-HSD1 and GC metabolism in mediating aspects of the H6PDHKO myopathy. To achieve this, we examined 11β-HSD1\\/H6PDH double-KO (DKO) mice, in which 11β-HSD1 mediated GC inactivation is negated. In contrast to H6PDHKO mice, DKO mice GC metabolism and hypothalamic-pituitary-adrenal axis set point is similar to that observed in 11β-HSD1KO mice. Critically, in contrast to 11β-HSD1KO mice, DKO mice phenocopy the salient features of the H6PDHKO, displaying reduced body mass, muscle atrophy, and vacuolation of type II fiber-rich muscle, fasting hypoglycemia, increased muscle glycogen deposition, and elevated expression of UPR genes. We propose that muscle G6P metabolism through H6PDH may be as important as changes in the redox environment when considering the mechanism underlying the activation of the UPR and the ensuing myopathy in H6PDHKO and DKO mice. These data are consistent with an 11β-HSD1-independent function for H6PDH in which sarcoplasmic reticulum G6P metabolism and nicotinamide adenine dinucleotide phosphate-(oxidized)\\/nicotinamide adenine dinucleotide phosphate (reduced) redox status are important for maintaining muscle homeostasis.

Thermodynamics of the localized D2-D6 system

International Nuclear Information System (INIS)

Gomez-Reino, Marta; Naculich, Stephen G.; Schnitzer, Howard J.

2005-01-01

An exact fully-localized extremal supergravity solution for N 2 D2-branes and N 6 D6-branes, which is dual to 3-dimensional supersymmetric SU(N 2 ) gauge theory with N 6 fundamentals, was found by Cherkis and Hashimoto. In order to consider the thermal properties of the gauge theory we present the non-extremal extension of this solution to first order in an expansion near the core of the D6-branes. We compute the Hawking temperature and the black-brane horizon area/entropy. The leading-order entropy, which is proportional to N 2 3/2 N 6 1/2 T H 2 , is not corrected to first order in the expansion. This result is consistent with the analogous weak-coupling result at the correspondence point N 2 similar to N 6

Forward absolute cross-section of the reaction /sup 2/H(d,n)/sup 3/He for Esub(d) = (3/6)MeV

Energy Technology Data Exchange (ETDEWEB)

Pavan, P.; Toniolo, D.; Zago, G.; Zannoni, R. (Padua Univ. (Italy). Ist. di Fisica); Galeazzi, G.

1981-12-01

The zero-degree differential cross-section of the reaction /sup 2/H(d,n)/sup 3/He was measured, by means of a recoil-proton neutron counter telescope, with an accuracy of 2%, in the incident-deuteron energy interval from 3 to 6 MeV.

Forward absolute cross-section of the reaction /sup 2/H(d,n)/sup 3/He for Esub(d)=(3/6)MeV

Energy Technology Data Exchange (ETDEWEB)

Pavan, P.; Toniolo, D.; Zago, G.; Zannoni, R. (Padua Univ. (Italy). Ist. di Fisica; Istituto Nazionale di Fisica Nucleare, Padua (Italy)); Galeazzi, G. (Istituto Nazionale di Fisica Nucleare, Padua (Italy). Lab. di Legnaro)

1981-12-01

The zero-degree differential cross-section of the reaction /sup 2/H(d,n)/sup 3/He was measured, by means of a recoil-proton neutron counter telescope, with an accuracy of 2%, in the incident deuteron energy interval form 3 to 6 MeV.

Preparation of butadiene D{sub 6} -1-1-2-3-4-4; Preparation du butadiene D{sub 6} -1-1-2-3-4-4

Energy Technology Data Exchange (ETDEWEB)

Pichat, L; Chatelain, G [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

1959-07-01

A description of the preparation of butadiene D{sub 6} by dehalogenation of perchlorobutadiene by zinc and heavy water in dioxane. (author) [French] Description de la preparation du butadiene D{sub 6} par reduction deshalogenante du perchlorobutadiene par le zinc et l'eau lourde dans le dioxane. (auteur)

A laboratory study of ikaite (CaCO3·6H2O) precipitation as a function of pH, salinity, temperature and phosphate concentration

OpenAIRE

Hu, Yu-Bin; Wolf-Gladrow, Dieter A.; Dieckmann, Gerhard S.; Völker, Christoph; Nehrke, Gernot

2014-01-01

Ikaite (CaCO3·6H2O) has only recently been discovered in sea ice, in a study that also provided first direct evidence of CaCO3 precipitation in sea ice. However, little is as yet known about the impact of physico-chemical processes on ikaite precipitation in sea ice. Our study focused on how the changes in pH, salinity, temperature and phosphate (PO4) concentration affect the precipitation of ikaite. Experiments were set up at pH from 8.5 to 10.0, salinities from 0 to 105 (in both artificial ...

Lithium-aluminum-zinc phosphate glasses activated with Tb3+ and Tb3+/Eu3+ for green laser medium, reddish-orange and white phosphor applications

Science.gov (United States)

Francisco-Rodriguez, H. I.; Lira, A.; Soriano-Romero, O.; Meza-Rocha, A. N.; Bordignon, S.; Speghini, A.; Lozada-Morales, R.; Caldiño, U.

2018-05-01

A spectroscopic analysis of Tb3+ and Tb3+/Eu3+ doped lithium-aluminum-zinc phosphate glasses is performed through their absorbance and photoluminescence spectra, and decay time profiles. Laser parameter values (stimulated emission cross section, effective bandwidth, gain bandwidth and optical gain) were obtained for the terbium 5D4 → 7F5 green emission from the Tb3+ singly-doped glass (LAZT) excited at 350 nm to judge the suitability of the glass phosphor for fiber lasers. A quantum yield of (47.68 ± 0.49)% was measured for the 5D4 level luminescence. Upon 350 nm excitation the LAZT glass phosphor emits green light with a color purity of 65.6% and chromaticity coordinates (0.285, 0.585) very close to those (0.29, 0.60) of European Broadcasting Union illuminant green. The Tb3+/Eu3+codoped glass emission color can be tuned from reddish-orange of 1865 K upon 318 nm excitation to warm white of 3599 K and neutral white of 4049 K upon 359 and 340 nm excitations, respectively. Upon Tb3+ excitation at 340 nm Eu3+ is sensitized by Tb3+ through a non-radiative energy transfer with an efficiency of 0.23-0.26. An electric dipole-dipole interaction might be the dominant mechanism in the Tb3+ to Eu3+ energy transfer taking place into Tb3+ - Eu3+ clusters.

Luminescence studies on Dy3+ and Dy3+:Eu3+ co-doped boro-phosphate glasses for WLED applications

Science.gov (United States)

Vijayakumar, M.; Uma, V.; Arunkumar, S.; Marimuthu, K.

2015-06-01

Dy3+ and Dy3+:Eu3+ co-doped boro-phosphate glasses have been prepared and optically characterized using absorption, luminescence and decay measurements. The Nephelauxetic ratios (β), Bonding parameters (δ) and Judd-Ofelt (JO) intensity parameters Ωλ (λ = 2, 4 and 6) were calculated to study the nature of the environment around the RE3+ ions in the prepared glasses. The yellow to blue (Y/B) intensity ratio and the chromaticity color coordinates were calculated from the luminescence measurements. The lifetimes of the 4F9/2 excited level were measured using decay curves and is found to decrease in the Dy3+:Eu3+ co-doped glass due to the occurrence of resonant energy transfer between Dy3+-Eu3+ ions and the non-exponential decay rates have been fitted with Inokuti-Hirayama (IH) model. The decay curves are well fitted for S= 6 suggesting that the interaction between active ions for the energy transfer is of dipole-dipole nature.

He I D3 OBSERVATIONS OF THE 1984 MAY 22 M6.3 SOLAR FLARE

Energy Technology Data Exchange (ETDEWEB)

Liu Chang; Xu Yan; Deng Na; Lee, Jeongwoo; Zhang Jifeng; Wang Haimin [Space Weather Research Laboratory, Center for Solar-Terrestrial Research, New Jersey Institute of Technology, University Heights, Newark, NJ 07102-1982 (United States); Prasad Choudhary, Debi, E-mail: chang.liu@njit.edu [Physics and Astronomy Department, California State University Northridge, 18111 Nordhoff Street, Northridge, CA 91330-0001 (United States)

2013-09-01

The He I D3 line has a unique response to a flare impact on the low solar atmosphere and can be a powerful diagnostic tool for energy transport processes. Using images obtained from the recently digitized films of the Big Bear Solar Observatory, we report D3 observations of the M6.3 flare on 1984 May 22, which occurred in an active region with a circular magnetic polarity inversion line (PIL). The impulsive phase of the flare starts with a main elongated source that darkens in D3, inside of which bright emission kernels appear at the time of the initial small peak in hard X-rays (HXRs). These flare cores subsequently evolve into a sharp emission strand lying within the dark halo; this evolution occurs at the same time as the main peak in HXRs, reversing the overall source contrast from -5% to 5%. The radiated energy in D3 during the main peak is estimated to be about 10{sup 30} erg, which is comparable to that carried by nonthermal electrons above 20 keV. Afterward, the flare proceeds along the circular PIL in the counterclockwise direction to form a dark circular ribbon in D3, which apparently mirrors the bright ribbons in H{alpha} and He I 10830 A. All of these ribbons last for over one hour in the late gradual phase. We suggest that the present event resembles the so-called black-light flare that was proposed based on continuum images, and that D3 darkening and brightening features herein may be due to thermal conduction heating and the direct precipitation of high-energy electrons, respectively.

Phosphate regulates chondrogenesis in a biphasic and maturation-dependent manner.

Science.gov (United States)

Wu, Biming; Durisin, Emily K; Decker, Joseph T; Ural, Evran E; Shea, Lonnie D; Coleman, Rhima M

Inorganic phosphate (Pi) has been recognized as an important signaling molecule that modulates chondrocyte maturation and cartilage mineralization. However, conclusive experimental evidence for its involvement in early chondrogenesis is still lacking. Here, using high-density monolayer (2D) and pellet (3D) culture models of chondrogenic ATDC5 cells, we demonstrate that the cell response to Pi does not correlate with the Pi concentration in the culture medium but is better predicted by the availability of Pi on a per cell basis (Pi abundance). Both culture models were treated with ITS+, 10mM β-glycerophosphate (βGP), or ITS+/10mM βGP, which resulted in three levels of Pi abundance in cultures: basal (Pi/DNA 60ng/µg). In chondrogenic medium alone, the abundance levels were at the basal level in 2D culture and moderate in 3D cultures. The addition of 10mM βGP resulted in moderate abundance in 2D and high abundance in 3D cultures. Moderate Pi abundance enhanced early chondrogenesis and production of aggrecan and type II collagen whereas high Pi abundance inhibited chondrogenic differentiation and induced rapid mineralization. Inhibition of sodium phosphate transporters reduced phosphate-induced expression of chondrogenic markers. When 3D ITS+/βGP cultures were treated with levamisole to reduce ALP activity, Pi abundance was decreased to moderate levels, which resulted in significant upregulation of chondrogenic markers, similar to the response in 2D cultures. Delay of phosphate delivery until after early chondrogenesis occurs (7 days) no longer enhanced chondrogenesis, but instead accelerated hypertrophy and mineralization. Together, our data highlights the dependence of chondroprogenitor cell response to Pi on its availability to individual cells and the chondrogenic maturation stage of these cells and suggest that appropriate temporal delivery of phosphate to ATDC5 cells in 3D cultures represents a rapid model for mechanistic studies into the effects of

An unexpected phosphate binding site in Glyceraldehyde 3-Phosphate Dehydrogenase: Crystal structures of apo, holo and ternary complex of Cryptosporidium parvum enzyme

Energy Technology Data Exchange (ETDEWEB)

Cook, William J; Senkovich, Olga; Chattopadhyay, Debasish; (UAB)

2009-06-08

The structure, function and reaction mechanism of glyceraldehyde 3-phosphate dehydrogenase (GAPDH) have been extensively studied. Based on these studies, three anion binding sites have been identified, one 'Ps' site (for binding the C-3 phosphate of the substrate) and two sites, 'Pi' and 'new Pi', for inorganic phosphate. According to the original flip-flop model, the substrate phosphate group switches from the 'Pi' to the 'Ps' site during the multistep reaction. In light of the discovery of the 'new Pi' site, a modified flip-flop mechanism, in which the C-3 phosphate of the substrate binds to the 'new Pi' site and flips to the 'Ps' site before the hydride transfer, was proposed. An alternative model based on a number of structures of B. stearothermophilus GAPDH ternary complexes (non-covalent and thioacyl intermediate) proposes that in the ternary Michaelis complex the C-3 phosphate binds to the 'Ps' site and flips from the 'Ps' to the 'new Pi' site during or after the redox step. We determined the crystal structure of Cryptosporidium parvum GAPDH in the apo and holo (enzyme + NAD) state and the structure of the ternary enzyme-cofactor-substrate complex using an active site mutant enzyme. The C. parvum GAPDH complex was prepared by pre-incubating the enzyme with substrate and cofactor, thereby allowing free movement of the protein structure and substrate molecules during their initial encounter. Sulfate and phosphate ions were excluded from purification and crystallization steps. The quality of the electron density map at 2{angstrom} resolution allowed unambiguous positioning of the substrate. In three subunits of the homotetramer the C-3 phosphate group of the non-covalently bound substrate is in the 'new Pi' site. A concomitant movement of the phosphate binding loop is observed in these three subunits. In the fourth subunit the C-3 phosphate

An unexpected phosphate binding site in Glyceraldehyde 3-Phosphate Dehydrogenase: Crystal structures of apo, holo and ternary complex of Cryptosporidium parvum enzyme

Directory of Open Access Journals (Sweden)

Chattopadhyay Debasish

2009-02-01

Full Text Available Abstract Background The structure, function and reaction mechanism of glyceraldehyde 3-phosphate dehydrogenase (GAPDH have been extensively studied. Based on these studies, three anion binding sites have been identified, one 'Ps' site (for binding the C-3 phosphate of the substrate and two sites, 'Pi' and 'new Pi', for inorganic phosphate. According to the original flip-flop model, the substrate phosphate group switches from the 'Pi' to the 'Ps' site during the multistep reaction. In light of the discovery of the 'new Pi' site, a modified flip-flop mechanism, in which the C-3 phosphate of the substrate binds to the 'new Pi' site and flips to the 'Ps' site before the hydride transfer, was proposed. An alternative model based on a number of structures of B. stearothermophilus GAPDH ternary complexes (non-covalent and thioacyl intermediate proposes that in the ternary Michaelis complex the C-3 phosphate binds to the 'Ps' site and flips from the 'Ps' to the 'new Pi' site during or after the redox step. Results We determined the crystal structure of Cryptosporidium parvum GAPDH in the apo and holo (enzyme + NAD state and the structure of the ternary enzyme-cofactor-substrate complex using an active site mutant enzyme. The C. parvum GAPDH complex was prepared by pre-incubating the enzyme with substrate and cofactor, thereby allowing free movement of the protein structure and substrate molecules during their initial encounter. Sulfate and phosphate ions were excluded from purification and crystallization steps. The quality of the electron density map at 2Å resolution allowed unambiguous positioning of the substrate. In three subunits of the homotetramer the C-3 phosphate group of the non-covalently bound substrate is in the 'new Pi' site. A concomitant movement of the phosphate binding loop is observed in these three subunits. In the fourth subunit the C-3 phosphate occupies an unexpected site not seen before and the phosphate binding loop remains in

Overexpression, crystallization and preliminary X-ray crystallographic analysis of erythronate-4-phosphate dehydrogenase from Pseudomonas aeruginosa

Energy Technology Data Exchange (ETDEWEB)

Ha, Jun Yong; Lee, Ji Hyun; Kim, Kyoung Hoon; Kim, Do Jin; Lee, Hyung Ho; Kim, Hye-Kyung; Yoon, Hye-Jin; Suh, Se Won, E-mail: sewonsuh@snu.ac.kr [Department of Chemistry, College of Natural Sciences, Seoul National University, Seoul 151-742 (Korea, Republic of)

2006-02-01

Erythronate-4-phosphate dehydrogenase from P. aeruginosa was crystallized and X-ray diffraction data were collected to 2.20 Å resolution. The enzyme erythronate-4-phosphate dehydrogenase catalyses the conversion of erythronate-4-phosphate to 3-hydroxy-4-phospho-hydroxy-α-ketobutyrate. It belongs to the d-isomer-specific 2-hydroxyacid dehydrogenase family. It is essential for de novo biosynthesis of vitamin B{sub 6} (pyridoxine). Erythronate-4-phosphate dehydrogenase from Pseudomonas aeruginosa, a homodimeric enzyme consisting of two identical 380-residue subunits, has been overexpressed in Escherichia coli with a C-terminal purification tag and crystallized at 297 K using 0.7 M ammonium dihydrogen phosphate, 0.4 M ammonium tartrate, 0.1 M sodium citrate pH 5.6 and 10 mM cupric chloride. X-ray diffraction data were collected to 2.20 Å from a crystal grown in the presence of NADH. The crystals belong to the orthorhombic space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 84.77, b = 101.28, c = 142.58 Å. A dimeric molecule is present in the asymmetric unit, giving a crystal volume per protein weight (V{sub M}) of 3.64 Å{sup 3} Da{sup −1} and a solvent content of 66%.

Overexpression, crystallization and preliminary X-ray crystallographic analysis of erythronate-4-phosphate dehydrogenase from Pseudomonas aeruginosa

International Nuclear Information System (INIS)

Ha, Jun Yong; Lee, Ji Hyun; Kim, Kyoung Hoon; Kim, Do Jin; Lee, Hyung Ho; Kim, Hye-Kyung; Yoon, Hye-Jin; Suh, Se Won

2006-01-01

Erythronate-4-phosphate dehydrogenase from P. aeruginosa was crystallized and X-ray diffraction data were collected to 2.20 Å resolution. The enzyme erythronate-4-phosphate dehydrogenase catalyses the conversion of erythronate-4-phosphate to 3-hydroxy-4-phospho-hydroxy-α-ketobutyrate. It belongs to the d-isomer-specific 2-hydroxyacid dehydrogenase family. It is essential for de novo biosynthesis of vitamin B 6 (pyridoxine). Erythronate-4-phosphate dehydrogenase from Pseudomonas aeruginosa, a homodimeric enzyme consisting of two identical 380-residue subunits, has been overexpressed in Escherichia coli with a C-terminal purification tag and crystallized at 297 K using 0.7 M ammonium dihydrogen phosphate, 0.4 M ammonium tartrate, 0.1 M sodium citrate pH 5.6 and 10 mM cupric chloride. X-ray diffraction data were collected to 2.20 Å from a crystal grown in the presence of NADH. The crystals belong to the orthorhombic space group P2 1 2 1 2 1 , with unit-cell parameters a = 84.77, b = 101.28, c = 142.58 Å. A dimeric molecule is present in the asymmetric unit, giving a crystal volume per protein weight (V M ) of 3.64 Å 3 Da −1 and a solvent content of 66%

Complex formation of uranium(VI) with fructose and glucose phosphates

International Nuclear Information System (INIS)

Koban, A.; Geipel, G.; Bernhard, G.; Fanghaenel, T.

2002-01-01

The uptake of heavy metals into plants is commonly quantified by the soil-plant transfer factor. Up to now little is known about the chemical speciation of actinides in plants. To compare the obtained spectroscopic data of uranium complexes in plants with model compounds, we investigate the complexation of uranium with relevant bioligands of various functionalities. A very important class of ligands consists of phosphate esters, which serve as phosphate group and energy transmitters as well as energy storage media in biological systems. Heavy metal ions bound to the phosphate esters can be transported into living cells and then deposited. Therefore, in our study we present the results of uranium complexation with glucose-6-phosphate (G6P), and fructose-6-phosphate (F6P) obtained by time-resolved laser-induced fluorescence spectroscopy (TRLFS). The experiments were performed at a fixed uranyl concentration (10 -5 M) as a function of the ligand concentrations (10 -5 to 10 -3 M) in a pH range from 2 to 4.5. For the glucose phosphate system we observed, using increasing ligand concentrations, a decrease in the fluorescence intensity and a small red shift of the emission bands. From this we conclude that the complexed uranyl glucose phosphate species show only minor or no fluorescence properties. The TRLFS spectra of the glucose phosphate samples indicated the presence of a single species with fluorescence properties. This species has a lifetime of approximately 1.5 μs and was identified as the free uranyl ion. An opposite phenomenon was observed for the fructose phosphate system: there was no decrease in fluorescence intensity. However, a strong red shift of the spectra was observed, illustrating the fluorescence properties of the uranyl fructose phosphate complex. The TRLFS spectra of the fructose phosphate system showed a second lifetime ( 2 2+ UO 2 (lig) x (2-y)+ + y H + (lig = sugar phosphate). Applying the mass action law and transformation to the logarithmic

Research into releasing inorganic phosphate and base from 5'-dTMP irradiated by a low energy ion beam

International Nuclear Information System (INIS)

Shao Chunlin; Yu Zengliang

1994-01-01

Research into radiation damage of nucleotide is an important area in radiation biology. In this paper, the yield of inorganic phosphate and base released from 5'-dTMP irradiated by a 30 keV N + ion beam was investigated in several aspects. The effect of particle fluence on yield and the influence of treatment with 0.1 N NaOH was deduced. By analysis, it is known that the alkali treatment not only increases the yield of inorganic phosphate, but also damages and splits the base released from irradiated 5'-dTMP. When the irradiated samples are treated by 0.1 N NaOH immediately, the yield of inorganic phosphate is increased by a factor of 1.7 and the concentration of base decreased to half of the original value. But the yield of inorganic phosphate could be increased by a factor of 2.8 after 40 min of alkali treatment. On the other hand, when 5'dTMP was irradiated by the ion beam, the G(Pi) obtained was above 0.44, higher than with γ-radiation. (Author)

Awakening sleeping beauty: production of propionic acid in Escherichia coli through the sbm operon requires the activity of a methylmalonyl-CoA epimerase.

Science.gov (United States)

Gonzalez-Garcia, Ricardo Axayacatl; McCubbin, Tim; Wille, Annalena; Plan, Manuel; Nielsen, Lars Keld; Marcellin, Esteban

2017-07-17

Propionic acid is used primarily as a food preservative with smaller applications as a chemical building block for the production of many products including fabrics, cosmetics, drugs, and plastics. Biological production using propionibacteria would be competitive against chemical production through hydrocarboxylation of ethylene if native producers could be engineered to reach near-theoretical yield and good productivity. Unfortunately, engineering propionibacteria has proven very challenging. It has been suggested that activation of the sleeping beauty operon in Escherichia coli is sufficient to achieve propionic acid production. Optimising E. coli production should be much easier than engineering propionibacteria if tolerance issues can be addressed. Propionic acid is produced in E. coli via the sleeping beauty mutase operon under anaerobic conditions in rich medium via amino acid degradation. We observed that the sbm operon enhances amino acids degradation to propionic acid and allows E. coli to degrade isoleucine. However, we show here that the operon lacks an epimerase reaction that enables propionic acid production in minimal medium containing glucose as the sole carbon source. Production from glucose can be restored by engineering the system with a methylmalonyl-CoA epimerase from Propionibacterium acidipropionici (0.23 ± 0.02 mM). 1-Propanol production was also detected from the promiscuous activity of the native alcohol dehydrogenase (AdhE). We also show that aerobic conditions are favourable for propionic acid production. Finally, we increase titre 65 times using a combination of promoter engineering and process optimisation. The native sbm operon encodes an incomplete pathway. Production of propionic acid from glucose as sole carbon source is possible when the pathway is complemented with a methylmalonyl-CoA epimerase. Although propionic acid via the restored succinate dissimilation pathway is considered a fermentative process, the engineered pathway

Radiological impact of natural radioactivity in Egyptian phosphate rocks, phosphogypsum and phosphate fertilizers

International Nuclear Information System (INIS)

El-Bahi, S.M.; Sroor, A.; Mohamed, Gehan Y.; El-Gendy, N.S.

2017-01-01

In this study, the activity concentrations of the natural radionuclides in phosphate rocks and its products were measured using a high- purity germanium detector (HPGe). The obtained activity results show remarkable wide variation in the radioactive contents for the different phosphate samples. The average activity concentration of "2"3"5U, "2"3"8U, "2"2"6Ra, "2"3"2Th and "4"0K was found as (45, 1031, 786, 85 and 765 Bq/kg) for phosphate rocks, (28, 1234, 457, 123 and 819 Bq/kg) for phosphate fertilizers, (47, 663, 550, 79 and 870 Bq/kg) for phosphogypsum and (25, 543, 409, 54 and 897 Bq/kg) for single super phosphate respectively. Based on the measured activities, the radiological parameters (activity concentration index, absorbed gamma dose rate in outdoor and indoor and the corresponding annual effective dose rates and total excess lifetime cancer risk) were estimated to assess the radiological hazards. The total excess lifetime cancer risk (ELCR) has been calculated and found to be high in all samples, which related to high radioactivity, representing radiological risk for the health of the population. - Highlights: • Level of radioactivity of phosphate rocks and by-products samples. • The radiological health hazard parameters. • Radiological risk to the health of the population. • The excess lifetime cancer risk factor.

Thermodynamics of the localized D2-D6 system

Energy Technology Data Exchange (ETDEWEB)

Gomez-Reino, Marta [Martin Fisher School of Physics, Brandeis University, Waltham, MA 02454 (United States)]. E-mail: marta@brandeis.edu; Naculich, Stephen G. [Department of Physics, Bowdoin College, Brunswick, ME 04011 (United States)]. E-mail: naculich@bowdoin.edu; Schnitzer, Howard J. [Martin Fisher School of Physics, Brandeis University, Waltham, MA 02454 (United States)]. E-mail: schnitzer@brandeis.edu

2005-05-02

An exact fully-localized extremal supergravity solution for N{sub 2} D2-branes and N{sub 6} D6-branes, which is dual to 3-dimensional supersymmetric SU(N{sub 2}) gauge theory with N{sub 6} fundamentals, was found by Cherkis and Hashimoto. In order to consider the thermal properties of the gauge theory we present the non-extremal extension of this solution to first order in an expansion near the core of the D6-branes. We compute the Hawking temperature and the black-brane horizon area/entropy. The leading-order entropy, which is proportional to N{sub 2}{sup 3/2}N{sub 6}{sup 1/2}T{sub H}{sup 2}, is not corrected to first order in the expansion. This result is consistent with the analogous weak-coupling result at the correspondence point N{sub 2} similar to N{sub 6}.

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

DEFF Research Database (Denmark)

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

2016-01-01

Isoprenoids are used in many commercial applications and much work has gone into engineering microbial hosts for their production. Isoprenoids are produced either from acetyl-CoA via the mevalonate pathway or from pyruvate and glyceraldehyde 3-phosphate via the 1-deoxy-D-xylulose 5-phosphate (DXP......) pathway. Saccharomyces cerevisiae exclusively utilizes the mevalonate pathway to synthesize native isoprenoids and in fact the alternative DXP pathway has never been found or successfully reconstructed in the eukaryotic cytosol. There are, however, several advantages to isoprenoid synthesis via the DXP...... time, functional expression of the DXP pathway in S. cerevisiae. Under low aeration conditions, an engineered strain relying solely on the DXP pathway for isoprenoid biosynthesis achieved an endpoint biomass 80% of that of the same strain using the mevalonate pathway....

Third-order nonlinearity of Er3+-doped lead phosphate glass

Energy Technology Data Exchange (ETDEWEB)

Santos, C. C. [Universidade Federal do Ceara, Ceara, Brazil; Guedes Da Silva, Ilde [ORNL; Siqueira, J. P. [Instituto de Física de São Carlos, Universidade de São Paulo, Brazil; Misoguti, L. [Instituto de Física de São Carlos, Universidade de São Paulo, Brazil; Zilio, S. C. [Instituto de Física de São Carlos, Universidade de São Paulo, Brazil; Boatner, Lynn A [ORNL

2010-01-01

The third-order optical susceptibility and dispersion of the linear refractive index of Er3+-doped lead phosphate glass were measured in the wavelength range between 400 and 1940 nm by using the spectrally resolved femtosecond Maker fringes technique. The nonlinear refractive index obtained from the third-order susceptibility was found to be five times higher than that of silica, indicating that Er3+-doped lead phosphate glass is a potential candidate to be used as the base component for the fabrication of photonic devices. For comparison purposes, the Z-scan technique was also employed to obtain the values of the nonlinear refractive index of E-doped lead phosphate glass at several wavelengths, and the values obtained using the two techniques agree to within 15%.

Component on-shell actions of supersymmetric 3-branes: I. 3-brane in D = 6

International Nuclear Information System (INIS)

Bellucci, S; Sutulin, A; Kozyrev, N; Krivonos, S

2015-01-01

In the present and accompanying papers we explicitly construct the on-shell supersymmetric component actions for 3-branes moving in D = 6 and D = 8 within the nonlinear realizations framework. In the first paper we apply our scheme to construct the action of supersymmetric 3-brane in D = 6. It turns out that all ingredients entering the component action can be obtained almost algorithmically by using the nonlinear realizations approach. Within this approach, properly adapted to the construction of the on-shell component actions, we pay much attention to broken supersymmetry. Doing so, we were able to write the action in terms of purely geometric objects (vielbeins and covariant derivatives of the physical bosonic components), covariant with respect to broken supersymmetry. It turns out that all terms of the higher orders in the fermions are hidden inside these covariant derivatives and vielbeins. Moreover, the main part of the component action just mimics its bosonic cousin in which the ordinary space–time derivatives and the bosonic worldvolume are replaced by their covariant supersymmetric analogs. The Wess–Zumino term in the action, which does not exist in the bosonic case, can be also easily constructed in terms of reduced Cartan forms. Keeping the broken supersymmetry almost explicit, one may write the ansatz for the component action, fully defined up to two constant parameters. The role of the unbroken supersymmetry is just to fix these parameters. (paper)

Prevalence of glucose-6-phosphate dehydrogenase (G6PD) deficiency among malaria patients in Upper Myanmar.

Science.gov (United States)

Lee, Jinyoung; Kim, Tae Im; Kang, Jung-Mi; Jun, Hojong; Lê, Hương Giang; Thái, Thị Lam; Sohn, Woon-Mok; Myint, Moe Kyaw; Lin, Khin; Kim, Tong-Soo; Na, Byoung-Kuk

2018-03-16

Glucose-6-phosphate dehydrogenase (G6PD; EC 1.1.1.49) deficiency is one of the most common X-linked recessive hereditary disorders in the world. Primaquine (PQ) has been used for radical cure of P. vivax to prevent relapse. Recently, it is also used to reduce P. falciparum gametocyte carriage to block transmission. However, PQ metabolites oxidize hemoglobin and generate excessive reactive oxygen species which can trigger acute hemolytic anemia in malaria patients with inherited G6PD deficiency. A total of 252 blood samples collected from malaria patients in Myanmar were used in this study. G6PD variant was analysed by a multiplex allele specific PCR kit, DiaPlexC™ G6PD Genotyping Kit [Asian type]. The accuracy of the multiplex allele specific PCR was confirmed by sequencing analysis. Prevalence and distribution of G6PD variants in 252 malaria patients in Myanmar were analysed. Six different types of G6PD allelic variants were identified in 50 (7 females and 43 males) malaria patients. The predominant variant was Mahidol (68%, 34/50), of which 91.2% (31/34) and 8.8% (3/34) were males and females, respectively. Other G6PD variants including Kaiping (18%, 9/50), Viangchan (6%, 3/50), Mediterranean (4%, 2/50), Union (2%, 1/50) and Canton (2%, 1/50) were also observed. Results of this study suggest that more concern for proper and safe use of PQ as a radical cure of malaria in Myanmar is needed by combining G6PD deficiency test before PQ prescription. Establishment of a follow-up system to monitor potential PQ toxicity in malaria patients who are given PQ is also required.

Glyceraldehyde-3-phosphate Dehydrogenase (GAPDH) Is Pyruvylated during 3-Bromopyruvate Mediated Cancer Cell Death

Science.gov (United States)

Ganapathy-Kanniappan, Shanmugasundaram; Geschwind, Jean-Francois H.; Kunjithapatham, Rani; Buijs, Manon; Vossen, Josephina A.; Tchernyshyov, Irina; Cole, Robert N.; Syed, Labiq H.; Rao, Pramod P.; Ota, Shinichi; Vali, Mustafa

2013-01-01

Background The pyruvic acid analog 3-bromopyruvate (3BrPA) is an alkylating agent known to induce cancer cell death by blocking glycolysis. The anti-glycolytic effect of 3BrPA is considered to be the inactivation of glycolytic enzymes. Yet, there is a lack of experimental documentation on the direct interaction of 3BrPA with any of the suggested targets during its anticancer effect. Methods and Results In the current study, using radiolabeled (14C) 3BrPA in multiple cancer cell lines, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was identified as the primary intracellular target of 3BrPA, based on two-dimensional (2D) gel electrophoretic autoradiography, mass spectrometry and immunoprecipitation. Furthermore, in vitro enzyme kinetic studies established that 3BrPA has marked affinity to GAPDH. Finally, Annexin V staining and active caspase-3 immunoblotting demonstrated that apoptosis was induced by 3BrPA. Conclusion GAPDH pyruvylation by 3BrPA affects its enzymatic function and is the primary intracellular target in 3BrPA mediated cancer cell death. PMID:20044597

Phospholipid composition and a polybasic motif determine D6 PROTEIN KINASE polar association with the plasma membrane and tropic responses.

Science.gov (United States)

Barbosa, Inês C R; Shikata, Hiromasa; Zourelidou, Melina; Heilmann, Mareike; Heilmann, Ingo; Schwechheimer, Claus

2016-12-15

Polar transport of the phytohormone auxin through PIN-FORMED (PIN) auxin efflux carriers is essential for the spatiotemporal control of plant development. The Arabidopsis thaliana serine/threonine kinase D6 PROTEIN KINASE (D6PK) is polarly localized at the plasma membrane of many cells where it colocalizes with PINs and activates PIN-mediated auxin efflux. Here, we show that the association of D6PK with the basal plasma membrane and PINs is dependent on the phospholipid composition of the plasma membrane as well as on the phosphatidylinositol phosphate 5-kinases PIP5K1 and PIP5K2 in epidermis cells of the primary root. We further show that D6PK directly binds polyacidic phospholipids through a polybasic lysine-rich motif in the middle domain of the kinase. The lysine-rich motif is required for proper PIN3 phosphorylation and for auxin transport-dependent tropic growth. Polybasic motifs are also present at a conserved position in other D6PK-related kinases and required for membrane and phospholipid binding. Thus, phospholipid-dependent recruitment to membranes through polybasic motifs might not only be required for D6PK-mediated auxin transport but also other processes regulated by these, as yet, functionally uncharacterized kinases. © 2016. Published by The Company of Biologists Ltd.

Mixed phosphates of the Na3PO4 - LnPO4 systems

International Nuclear Information System (INIS)

Slivko, T.A.; Smirnova, I.N.; Zimina, G.V.; Spiridonov, F.M.; Chudinova, N.N.

2002-01-01

The phase relationships in the systems Na 3 PO 4 - LnPO 4 (subsolidus 950 Deg C cross-sections), where Ln=Sm, Eu, Tb, Dy, Ho, Tm, Yb, Lu, were studied by X-ray analysis. Reactions of the components were deduced, formed phases were separated and identified. The Na 6 Ln 3 (PO 4 ) 5 (Ln=Dy, Ho, Tm), Na 3 Ln 2 (PO 4 ) 3 (Ln=Tm, Yb, Lu) compounds and phases of the unstable composition Na 6+x Ln 3-x/3 (PO 4 ) 5 (Ln=Yb, Lu, 0 ≤ x ≤ 1.5) were detected for the first time. In all systems the existence of the Na 3-x Ln x/3 PO 4 unstable composition phase on the basis of the high temperature modification of sodium phosphate (sp. gr. Fm3m) is established, suggesting that stabilization of this modification by rare earth ions is possible [ru

Kinetic study of Tb/sup 3 +/(/sup 5/D/sub 3/) luminescence in phosphate glasses

Energy Technology Data Exchange (ETDEWEB)

Anisimov, V.A.; Dmitryuk, A.V.; Karapetyan, G.O.

1986-01-01

This paper presents precise determinations of the kinetics of terbium luminescence over a broad dynamic range, in order to refine the mechanism of concentration quenching of the Tb/sup 3 +/(/sup 5/D/sub 3/) luminescence in glasses. After establishing the mechanism of Tb/sup 3 +/(/sup 5/D/sub 3/) luminescence quenching by the iteration method, the authors determine the value of the parameter for an arbitrary concentration of the activator. Results of this study show that the mechanism of concentration quenching of luminescence is static dipole-dipole interaction of terbium ions.

Methadone inhibits CYP2D6 and UGT2B7/2B4 in vivo: a study using codeine in methadone- and buprenorphine-maintained subjects

Science.gov (United States)

Gelston, Eloise A; Coller, Janet K; Lopatko, Olga V; James, Heather M; Schmidt, Helmut; White, Jason M; Somogyi, Andrew A

2012-01-01

AIMS To compare the O-demethylation (CYP2D6-mediated), N-demethylation (CYP3A4-mediated) and 6-glucuronidation (UGT2B4/7-mediated) metabolism of codeine between methadone- and buprenorphine-maintained CYP2D6 extensive metabolizer subjects. METHODS Ten methadone- and eight buprenorphine-maintained subjects received a single 60 mg dose of codeine phosphate. Blood was collected at 3 h and urine over 6 h and assayed for codeine, norcodeine, morphine, morphine-3- and -6-glucuronides and codeine-6-glucuronide. RESULTS The urinary metabolic ratio for O-demethylation was significantly higher (P = 0.0044) in the subjects taking methadone (mean ± SD, 2.8 ± 3.1) compared with those taking buprenorphine (0.60 ± 0.43), likewise for 6-glucuronide formation (0.31 ± 0.24 vs. 0.053 ± 0.027; P D6 and UGTs 2B4 and 2B7 reactions in vivo, even though it is not a substrate for these enzymes. Plasma morphine was not altered, owing to the opposing effects of inhibition of both formation and elimination; however, morphine-6-glucuronide (analgesically active) concentrations were substantially reduced. Drug interactions with methadone are likely to include drugs metabolized by various UGTs and CYP2D6. PMID:22092298

Synthesis of 3-aminopropyl β-(1 → 6)-d-glucotetraoside and its biotinylated derivative.

Science.gov (United States)

Yashunsky, Dmitry V; Karelin, Alexander A; Tsvetkov, Yury E; Nifantiev, Nikolay E

2018-01-02

3-Aminopropyl β-(1 → 6)-d-glucotetraoside has been synthesized from 3-benzyloxycarbonylaminopropanol and 6-O-acetyl-2,3,4-tri-O-benzoyl-d-glucopyranosyl trichloroacetimidate by successive attachment of one monosaccharide unit in total yield of 22%. Free aminopropyl glycoside was converted into a biotin derivative that can be used for controlled immobilization of the oligosaccharide on streptavidin-coated ELISA plates and for tracing carbohydrate binding molecules. Copyright © 2017 Elsevier Ltd. All rights reserved.

Hydrothermal synthesis and characterization of a two-dimensional piperazinium cobalt–zinc phosphate via a metastable one-dimensional phase

International Nuclear Information System (INIS)

Torre-Fernández, Laura; Khainakova, Olena A.; Espina, Aránzazu; Amghouz, Zakariae; Khainakov, Sergei A.; Alfonso, Belén F.; Blanco, Jesús A.; García, José R.; García-Granda, Santiago

2015-01-01

A two-dimensional piperazinium cobalt–zinc phosphate, formulated as (C 4 N 2 H 12 ) 1.5 (Co 0.6 Zn 0.4 ) 2 (HPO 4 ) 2 (PO 4 )·H 2 O (2D), was synthesized under hydrothermal conditions. The crystal structure was determined using single-crystal X-ray diffraction data (monoclinic P2 1 /c, a=8.1165(3) Å, b=26.2301(10) Å, c=8.3595(4) Å, and β=110.930(5)°) and the hydrogen atom positions were optimized by DFT calculations. A single-crystal corresponding to one-dimensional metastable phase, (C 4 N 2 H 12 )Co 0.3 Zn 0.7 (HPO 4 ) 2 ·H 2 O (1D), was also isolated and the crystal structure was determined (monoclinic P2 1 /c, a=8.9120(6) Å, b=14.0290(1) Å, c=12.2494(5) Å, and β=130.884(6)°). The bulk was characterized by chemical (C–H–N) analysis, powder X-ray diffraction (PXRD), powder X-ray thermodiffractometry (HT-XRD), transmission electron microscopy (STEM(DF)-EDX and EFTEM), and thermal analysis (TG/SDTA-MS), including activation energy data of its thermal decomposition. The magnetic susceptibility and magnetization measurements show no magnetic ordering down to 4 K. - Graphical abstract: Hydrothermal synthesis and structural characterization of a two-dimensional piperazinium cobalt–zinc phosphate, (C 4 N 2 H 12 ) 1.5 (Co 0.6 Zn 0.4 ) 2 (HPO 4 ) 2 (PO 4 )·H 2 O (2D), have been reported. The crystal structure of a one-dimensional piperazinium cobalt–zinc phosphate, (C 4 N 2 H 12 )Co 0.3 Zn 0.7 (HPO 4 ) 2 ·H 2 O (1D) a metastable phase during the hydrothermal synthesis, was also determined. The thermal behavior of 2D compound is strongly dependent on the selected heating rate and the magnetic susceptibility and magnetization measurements show no magnetic ordering down to 4 K. - Highlights: • A 2D piperazinium cobalt–zinc phosphate has been synthesized and characterized. • Crystal structure of 1D metastable phase was also determined. • Thermal behavior of 2D compound is strongly dependent on the selected heating rate. • Magnetic

Balancing mechanical strength with bioactivity in chitosan-calcium phosphate 3D microsphere scaffolds for bone tissue engineering: air- vs. freeze-drying processes.

Science.gov (United States)

Nguyen, D T; McCanless, J D; Mecwan, M M; Noblett, A P; Haggard, W O; Smith, R A; Bumgardner, J D

2013-01-01

The objective of this study was to evaluate the potential benefit of 3D composite scaffolds composed of chitosan and calcium phosphate for bone tissue engineering. Additionally, incorporation of mechanically weak lyophilized microspheres within those air-dried (AD) was considered for enhanced bioactivity. AD microsphere, alone, and air- and freeze-dried microsphere (FDAD) 3D scaffolds were evaluated in vitro using a 28-day osteogenic culture model with the Saos-2 cell line. Mechanical testing, quantitative microscopy, and lysozyme-driven enzymatic degradation of the scaffolds were also studied. FDAD scaffold showed a higher concentration (p < 0.01) in cells per scaffold mass vs. AD constructs. Collagen was ∼31% greater (p < 0.01) on FDAD compared to AD scaffolds not evident in microscopy of microsphere surfaces. Alternatively, AD scaffolds demonstrated a superior threefold increase in compressive strength over FDAD (12 vs. 4 MPa) with minimal degradation. Inclusion of FD spheres within the FDAD scaffolds allowed increased cellular activity through improved seeding, proliferation, and extracellular matrix production (as collagen), although mechanical strength was sacrificed through introduction of the less stiff, porous FD spheres.

Synthesis of C-glycosyl-bis-1,2,3-triazole derivatives from 3,4,6-tri-O-acetyl-D-glucal.

Science.gov (United States)

Shamim, Anwar; Souza, Frederico B; Trossini, Gustavo H G; Gatti, Fernando M; Stefani, Hélio A

2015-08-01

We have developed an efficient, CuI-catalyzed, microwave-assisted method for the synthesis of bis-1,2,3-triazole derivatives starting from a 3,4,6-tri-O-acetyl-D-glucal-derived mesylate. This mesylate was obtained from 3,4,6-tri-O-acetyl-D-glucal through C-glycosidation, deprotection of acetate groups to alcohols, and selective mesylation of the primary alcohol. This mesylate moiety was then converted to an azide through a microwave-assisted method with good yield. The azide, once synthesized, was then treated with different terminal alkynes in the presence of CuI to synthesize various bis-triazoles in high yields and short reaction times.

Ph effect on tricalcium phosphate (Ca3(PO4)2) thermoluminescence

International Nuclear Information System (INIS)

Barrera V, A.; Zarate M, J.; Lemus R, J.; Sanchez, A.; Rivera M, T.

2015-10-01

The study of the ph effect is presented on thermoluminescent response of calcium phosphates synthesized by precipitation process. For the synthesis by precipitation, were used: calcium nitrate (Ca(NO 3 ) 2 and ammonium phosphate dibasic ((NH 4 ) 2 HPO 4 ) as precursors. Samples were obtained at ph 7, 8, 9 and 10 and subjected to a calcination s temperature of 1100 C. Samples were also irradiated with X rays of 6 MV to a dose of 2 Gy. Samples prior to irradiation showed no luminescence, the irradiated samples displayed a luminescent curve which is due to the X-ray response. Powders synthesized at ph 7 showed a well-defined peak centered at 267 grades C. The rest of the prepared samples showed a luminescent curve composed of several peaks. By analyzing the curve at ph 7 by the method of the shape of the curve, was found to have an order of 1.7, with an activation energy, E = 1.44 ± 0.04 eV. (Author)

Processes of the excitation energy migration and transfer in Ce3+-doped alkali gadolinium phosphates studied with time-resolved photoluminescence spectroscopy technique

International Nuclear Information System (INIS)

Stryganyuk, G.; Shalapska, T.; Voloshinovskii, A.; Gektin, A.; Krasnikov, A.; Zazubovich, S.

2011-01-01

Spectral-kinetic characteristics of Gd 3+ and Ce 3+ luminescence from a series of Ce 3+ -doped alkali gadolinium phosphates of MGdP 4 O 12 type (M=Li, Na, Cs) have been studied within 4.2-300 K temperature range using time-resolved luminescence spectroscopy techniques. The processes of energy migration along the Gd 3+ sub-lattice and energy transfer between the Gd 3+ and Ce 3+ ions have been investigated. Peculiarities of these processes have been compared for MGdP 4 O 12 phosphate hosts with different alkali metal ions. A contribution of different levels from the 6 P j multiplet of the lowest Gd 3+ excited state into the energy migration and transfer processes has been clarified. The phonon-assisted occupation of high-energy 6 P 5/2,3/2 levels by Gd 3+ in the excited 6 P j state has been revealed as a shift of Gd 3+6 P j → 8 S 7/2 emission into the short-wavelength spectral range upon the temperature increase. The relaxation of excited Gd 3+ via phonon-assisted population of Gd 3+6 P 5/2 level (next higher one to the lowest excited 6 P 7/2 ) is supposed to be responsible for the rise in probability of energy migration within the Gd 3+ sub-lattice initiating the Gd 3+ →Ce 3+ energy transfer at T 3+ →Ce 3+ energy transfer at T>150 K is explained by the increase in probability of Gd 3+ relaxation into the highest 6 P 3/2 level of the 6 P j multiplet. An efficient reversed Ce 3+ →Gd 3+ energy transfer has been revealed for the studied phosphates at 4.2 K. - Highlights: →We investigate the Gd 3+ -Ce 3+ energy transfer in alkali gadolinium phosphates. → Thermal population of Gd 3+6 P 5/2 level improves migration along the Gd sub-lattice. → Increasing overlap of Gd 3+ and Ce 3+ states enhances the Gd 3+ -Ce 3+ energy transfer. → In LiGdP 4 O 12 :Ce and NaGdP 4 O 12 :Ce an efficient Ce 3+ -Gd 3+ transfer occurs at 4-300 K. → An effective reverse Gd 3+ -Ce 3+ energy transfer becomes possible at T>150 K.

Importance of glucose-6-phosphate dehydrogenase (G6PDH) for vanillin tolerance in Saccharomyces cerevisiae.

Science.gov (United States)

Nguyen, Trinh Thi My; Kitajima, Sakihito; Izawa, Shingo

2014-09-01

Vanillin is derived from lignocellulosic biomass and, as one of the major biomass conversion inhibitors, inhibits yeast growth and fermentation. Vanillin was recently shown to induce the mitochondrial fragmentation and formation of mRNP granules such as processing bodies and stress granules in Saccharomyces cerevisiae. Furfural, another major biomass conversion inhibitor, also induces oxidative stress and is reduced in an NAD(P)H-dependent manner to its less toxic alcohol derivative. Therefore, the pentose phosphate pathway (PPP), through which most NADPH is generated, plays a role in tolerance to furfural. Although vanillin also induces oxidative stress and is reduced to vanillyl alcohol in a NADPH-dependent manner, the relationship between vanillin and PPP has not yet been investigated. In the present study, we examined the importance of glucose-6-phosphate dehydrogenase (G6PDH), which catalyzes the rate-limiting NADPH-producing step in PPP, for yeast tolerance to vanillin. The growth of the null mutant of G6PDH gene (zwf1Δ) was delayed in the presence of vanillin, and vanillin was efficiently reduced in the culture of wild-type cells but not in the culture of zwf1Δ cells. Furthermore, zwf1Δ cells easily induced the activation of Yap1, an oxidative stress responsive transcription factor, mitochondrial fragmentation, and P-body formation with the vanillin treatment, which indicated that zwf1Δ cells were more susceptible to vanillin than wild type cells. These findings suggest the importance of G6PDH and PPP in the response of yeast to vanillin. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Overexpression, crystallization and preliminary X-­ray crystallographic analysis of erythronate-4-phosphate dehydrogenase from Pseudomonas aeruginosa

Science.gov (United States)

Ha, Jun Yong; Lee, Ji Hyun; Kim, Kyoung Hoon; Kim, Do Jin; Lee, Hyung Ho; Kim, Hye-Kyung; Yoon, Hye-Jin; Suh, Se Won

2006-01-01

The enzyme erythronate-4-phosphate dehydrogenase catalyses the conversion of erythronate-4-phosphate to 3-hydroxy-4-phospho-hydroxy-α-ketobutyrate. It belongs to the d-isomer-specific 2-hydroxyacid dehydrogenase family. It is essential for de novo biosynthesis of vitamin B6 (pyridoxine). Erythronate-4-­phosphate dehydrogenase from Pseudomonas aeruginosa, a homodimeric enzyme consisting of two identical 380-residue subunits, has been overexpressed in Escherichia coli with a C-terminal purification tag and crystallized at 297 K using 0.7 M ammonium dihydrogen phosphate, 0.4 M ammonium tartrate, 0.1 M sodium citrate pH 5.6 and 10 mM cupric chloride. X-ray diffraction data were collected to 2.20 Å from a crystal grown in the presence of NADH. The crystals belong to the orthorhombic space group P212121, with unit-cell parameters a = 84.77, b = 101.28, c = 142.58 Å. A dimeric molecule is present in the asymmetric unit, giving a crystal volume per protein weight (V M) of 3.64 Å3 Da−1 and a solvent content of 66%. PMID:16511285

Molecular magnetism of M6 hexagon ring in D(3d) symmetric [(MCl)6(XW9O33)2](12-) (M = Cu(II) and Mn(II), X = Sb(III) and As(III)).

Science.gov (United States)

Yamase, Toshihiro; Ishikawa, Hirofumi; Abe, Hiroko; Fukaya, Keisuke; Nojiri, Hiroyuki; Takeuchi, Hideo

2012-04-16

Ferromagnetic [n-BuNH(3)](12)[(CuCl)(6)(SbW(9)O(33))(2)]·6H(2)O (1) and antiferromagnetic [n-BuNH(3)](12)[(MnCl)(6)(AsW(9)O(33))(2)]·6H(2)O (4) have been synthesized and structurally and magnetically characterized. Two complexes are structural analogues of [n-BuNH(3)](12)[(CuCl)(6)(AsW(9)O(33))(2)]·6H(2)O (2) and [n-BuNH(3)](12)[(MnCl)(6)(SbW(9)O(33))(2)]·6H(2)O (3) with their ferromagnetic interactions, first reported by us in 2006. (1) When variable temperature (T) direct current (dc) magnetic susceptibility (χ(M)) data are analyzed with the isotropic exchange Hamiltonian for the magnetic exchange interactions, χ(M)T vs T curves fitted by a full matrix diagonalization (for 1) and by the Kambe vector coupling method/Van Vleck's approximation (for 4) yield J = +29.5 and -0.09 cm(-1) and g = 2.3 and 1.9, respectively. These J values were significantly distinguished from +61.0 and +0.14 cm(-1) for 2 and 3, respectively. The magnetization under the pulsed field (up to 10(3) T/s) at 0.5 K exhibits hysteresis loops in the adiabatic process, and the differential magnetization (dM/dB) plots against the pulsed field display peaks characteristic of resonant quantum tunneling of magnetization (QTM) at Zeeman crossed fields, indicating single-molecule magnets for 1-3. High-frequency ESR (HFESR) spectroscopy on polycrystalline samples provides g(∥) = 2.30, g(⊥) = 2.19, and D = -0.147 cm(-1) for 1 (S = 3 ground state), g(∥) = 2.29, g(⊥) = 2.20, and D = -0.145 cm(-1) for 2 (S = 3), and g(∥) = 2.03 and D = -0.007 cm(-1) for 3 (S = 15). An attempt to rationalize the magnetostructural correlation among 1-4, the structurally and magnetically modified D(3d)-symmetric M (=Cu(II) and Mn(II))(6) hexagons sandwiched by two diamagnetic α-B-[XW(9)O(33)](9-) (X = Sb(III) and As(III)) ligands through M-(μ(3)-O)-W linkages, is made. The strongest ferromagnetic coupling for the Cu(6) hexagon of 2, the structure of which approximately provides the Cu(6)(μ(3)-O)(12

Synthesis of cefepime-d3 and cefepime-d8

International Nuclear Information System (INIS)

Kamachi, Hajime; Okita, Takaaki; Tsuno, Takashi; Naito, Takayuki

1990-01-01

Synthesis of cefepime-d 3 (6a) and cefepime-d 8 (6b) is described. Diphenylmethyl 7-benzylideneamino-3-chloromethyl-3-cephem-4-carboxylate (2) was treated with sodium iodide to afford the iodide 3, which was without isolation, allowed to react with N-methyl-d 3 -pyrrolidine to give the quaternary salt 4a. Deblocking of 4a with HCO 2 H and HCl gave 7-amino-3-(N-methyl-d3-pyrrolidinio)methyl-3-cephem-4-carboxylate hydrochloride (5a). Acylation of 5a with benzotriazol-1-yl (Z)-2-(2-aminothiazol-4-yl)-2-methoxyiminoacetate followed by treatment with dil. H 2 SO 4 afforded 6a sulfate. In the same way, 6b was synthesized using N-methyl-pyrrolidine-d 8 . (author)

1α,25 dihydroxi-vitamin D3 modulates CDK4 and CDK6 expression and localization

International Nuclear Information System (INIS)

Irazoqui, Ana P.; Heim, Nadia B.; Boland, Ricardo L.; Buitrago, Claudia G.

2015-01-01

We recently reported that the vitamin D receptor (VDR) and p38 MAPK participate in pro-differentiation events triggered by 1α,25(OH) 2 -vitamin D 3 [1,25D] in skeletal muscle cells. Specifically, our studies demonstrated that 1,25D promotes G0/G1 arrest of cells inducing cyclin D3 and cyclin dependent kinases inhibitors (CKIs) p21 Waf1/Cip1 and p27 Kip1 expression in a VDR and p38 MAPK dependent manner. In this work we present data indicating that cyclin-dependent kinases (CDKs) 4 and 6 also play a role in the mechanism by which 1,25D stimulates myogenesis. To investigate VDR involvement in hormone regulation of CDKs 4 and 6, we significantly reduced its expression by the use of a shRNA against mouse VDR, generating the skeletal muscle cell line C2C12-VDR. Investigation of changes in cellular cycle regulating proteins by immunoblotting showed that the VDR is involved in the 1,25D –induced CDKs 4 and 6 protein levels at 6 h of hormone treatment. CDK4 levels remains high during S phase peak and G0/G1 arrest while CDK6 expression decreases at 12 h and increases again al 24 h. The up-regulation of CDKs 4 and 6 by 1,25D (6 h) was abolished in C2C12 cells pre-treated with the ERK1/2 inhibitor, UO126. Moreover, CDKs 4 and 6 expression induced by the hormone nor was detected when α and β isoforms of p38 MAPK were inhibited by compound SB203580. Confocal images show that there is not co-localization between VDR and CDKs at 6 h of hormone treatment, however CDK4 and VDR co-localizates in nucleus after 12 h of 1,25D exposure. Of relevance, at this time 1,25D promotes CDK6 localization in a peri-nuclear ring. Our data demonstrate that the VDR, ERK1/2 and p38 MAPK are involved in the control of CDKs 4 and 6 by 1,25D in skeletal muscle cells sustaining the operation of a VDR and MAPKs –dependent mechanism in hormone modulation of myogenesis. - Highlights: • 1,25D modulates CDKs 4 and 6 expression in skeletal muscle cells. • CDK4 co-localizates with VDR after 1

Plasma and milk concentrations of vitamin D3 and 25-hydroxy vitamin D3 following intravenous injection of vitamin D3 or 25-hydroxy vitamin D3.

OpenAIRE

Hidiroglou, M; Knipfel, J E

1984-01-01

Plasma levels of vitamin D3 or 25-hydroxyvitamin D3 in ewes after administration of a single massive intravenous dose of vitamin D3 (2 X 10(6) IU) or 25-hydroxy vitamin D3 (5 mg) were determined at zero, one, two, three, five, ten and 20 days postinjection. In six ewes injected with vitamin D3 conversion of vitamin D3 to 25-hydroxy vitamin D3 resulted in a six-fold increase in the plasma 25-hydroxy vitamin D3 level within one day. Elevated levels were maintained until day 10 but by day 20 a s...

ORF Alignment: NC_004337 [GENIUS II[Archive

Lifescience Database Archive (English)

Full Text Available NC_004337 gi|24113675 >1nbuA 1 118 5 120 2e-19 ... ref|NP_708185.1| D-erythro-7,8-dihydrone...opterin triphosphate epimerase [Shigella ... flexneri 2a str. 301] gb|AAN43892.1| ... D-erythro-7,8-dihydrone....1| ... D-erythro-7,8-dihydroneopterin triphosphate epimerase ... [...Shigella flexneri 2a str. 2457T] ref|NP_754732.1| ... D-erythro-7,8-dihydroneopterin triphosphate epi...merase ... [Escherichia coli CFT073] gb|AAP17710.1| ... D-erythro-7,8-dihydroneopterin triphos

ORF Alignment: NC_002655 [GENIUS II[Archive

Lifescience Database Archive (English)

Full Text Available NC_002655 gi|15802850 >1nbuA 1 118 5 120 2e-19 ... ref|NP_708185.1| D-erythro-7,8-dihydrone...opterin triphosphate epimerase [Shigella ... flexneri 2a str. 301] gb|AAN43892.1| ... D-erythro-7,8-dihydrone....1| ... D-erythro-7,8-dihydroneopterin triphosphate epimerase ... [...Shigella flexneri 2a str. 2457T] ref|NP_754732.1| ... D-erythro-7,8-dihydroneopterin triphosphate epi...merase ... [Escherichia coli CFT073] gb|AAP17710.1| ... D-erythro-7,8-dihydroneopterin triphos

ORF Alignment: NC_004431 [GENIUS II[Archive

Lifescience Database Archive (English)

Full Text Available NC_004431 gi|26248692 >1nbuA 1 118 5 120 2e-19 ... ref|NP_708185.1| D-erythro-7,8-dihydrone...opterin triphosphate epimerase [Shigella ... flexneri 2a str. 301] gb|AAN43892.1| ... D-erythro-7,8-dihydrone....1| ... D-erythro-7,8-dihydroneopterin triphosphate epimerase ... [...Shigella flexneri 2a str. 2457T] ref|NP_754732.1| ... D-erythro-7,8-dihydroneopterin triphosphate epi...merase ... [Escherichia coli CFT073] gb|AAP17710.1| ... D-erythro-7,8-dihydroneopterin triphos

ORF Alignment: NC_004741 [GENIUS II[Archive

Lifescience Database Archive (English)

Full Text Available NC_004741 gi|30063729 >1nbuA 1 118 5 120 2e-19 ... ref|NP_708185.1| D-erythro-7,8-dihydrone...opterin triphosphate epimerase [Shigella ... flexneri 2a str. 301] gb|AAN43892.1| ... D-erythro-7,8-dihydrone....1| ... D-erythro-7,8-dihydroneopterin triphosphate epimerase ... [...Shigella flexneri 2a str. 2457T] ref|NP_754732.1| ... D-erythro-7,8-dihydroneopterin triphosphate epi...merase ... [Escherichia coli CFT073] gb|AAP17710.1| ... D-erythro-7,8-dihydroneopterin triphos

The Mycobacterium tuberculosis Complex has a Pathway for the Biosynthesis of 4-Formamido-4,6-Dideoxy-d-Glucose.

Science.gov (United States)

Brown, Haley A; Vinogradov, Evgeny; Gilbert, Michel; Holden, Hazel M

2018-05-15

Recent studies have demonstrated that the O-antigens of some pathogenic bacteria such as Brucella abortus, Francisella tularensis, and Campylobacter jejuni contain quite unusual N-formylated sugars (3-formamido-3,6-dideoxy-d-glucose or 4-formamido-4,6-dideoxy-d-glucose). Typically, four enzymes are required for the formation of such sugars: a thymidylyltransferase, a 4,6-dehydratase, a pyridoxal 5'-phosphate or PLP-dependent aminotransferase, and an N-formyltransferase. To date, there have been no published reports of N-formylated sugars associated with Mycobacterium tuberculosis. A recent investigation from our laboratories, however, has demonstrated that one gene product from M. tuberculosis, Rv3404c, functions as a sugar N-formyltransferase. Given that M. tuberculosis produces l-rhamnose, both a thymidylyltransferase (Rv0334) and a 4,6-dehydratase (Rv3464) required for its formation have been identified. Thus, there is one remaining enzyme needed for the production of an N-formylated sugar in M. tuberculosis, namely a PLP-dependent aminotransferase. Here we demonstrate that the M. tuberculosis rv3402c gene encodes such an enzyme. Our data prove that M. tuberculosis contains all of the enzymatic activities required for the formation of dTDP-4-formamido-4,6-dideoxy-d-glucose. Indeed, the rv3402c gene product likely contributes to virulence or persistence during infection, though its temporal expression and location remain to be determined. This article is protected by copyright. All rights reserved. © 2018 The Protein Society.

Analysis of phosphate esters in plant material. Extraction and purification.

Science.gov (United States)

Isherwood, F A; Barrett, F C

1967-09-01

1. A critical study was made of the quantitative extraction of nucleotide and sugar phosphates from plant tissue by either boiling aqueous ethanol or cold trichloroacetic acid. The effect of the extraction technique on the inactivation of the enzymes in the plant tissue and the possibility of adsorption of the phosphate esters on the cell wall were especially considered. 2. In the recommended method the plant tissue was frozen in liquid nitrogen, ground to a powder and then blended with cold aqueous trichloroacetic acid containing 8-hydroxyquinoline to prevent adsorption. 3. The extract contained large amounts of trichloroacetic acid, cations, chloride, sugars, amino acids, hydroxy organic acids, phytic acid, orthophosphoric acid and high-molecular-weight material including some phosphorus-containing compounds. All of these were removed as they were liable to interfere with the chromatographic or enzymic assay of the individual nucleotide or sugar phosphates. 4. The procedure was as follows: the last traces of trichloroacetic acid were extracted with ether after the solution had been passed through a column of Dowex AG 50 in the hydrogen form to remove all cations. High-molecular-weight compounds were removed by ultrafiltration and low-molecular-weight solutes by a two-stage chromatography on cellulose columns with organic solvents. In the first stage, sugars, amino acids, chloride and phytic acid were separated by using a basic solvent (propan-1-ol-water-aqueous ammonia) and, in the second stage, the organic acids and orthophosphoric acid were separated by using an acidic solvent (di-isopropyl ether-formic acid-2-methylpropan-2-ol-water). The final solution of nucleotide and sugar phosphates was substantially free from other solutes and was suitable for the detection of individual phosphate esters by either chromatography or enzymic assay. 5. The recovery of d-glucose 6-phosphate or adenosine 5'-triphosphate added to a trichloroacetic acid extract simulating that

Acid indium strontium phosphate SrIn2[PO3(OH)]4: synthesis and crystal structure

International Nuclear Information System (INIS)

Rusakov, D.A.; Bobylev, A.P.; Komissarova, L.N.; Filaretov, A.A.; Danilov, V.P.

2007-01-01

Acid indium-strontium phosphate SrIn 2 [PO 3 (OH)] 4 is synthesized and characterized. Crystal structure and lattice parameters ate determined. In atoms in SrIn 2 [PO 3 (OH)] 4 structure are in distorted InO 6 octahedrons and form with PO 3 (OH) tetrahedrons mixed paraskeleton {In 2 [PO 3 (OH)] 4 } 3∞ 2- with emptinesses occupied by big Sr 2+ cations. The compound is thermally stable up to 400 Deg C [ru

Measurement of "2"2"6Ra and "2"2"8Ra in Brazilian and Israeli Phosphates

International Nuclear Information System (INIS)

Ferreira, W.; Canella Avelar, A.; Menezes, M.

2014-01-01

Since the 1970s, the IAEA recognizes that phosphoric acid presents an alternate source of uranium, but given the status of both phosphate and uranium markets the potential of recovering uranium from phosphoric acid still marginal. New technologies for the recovery of uranium from phosphoric acid, national and global interests and environment barriers could shape this market in the medium and long-term scenarios. On the other hand, the use of phosphates is the major source of phosphorus in agriculture and livestock. Beyond phosphorus and calcium, phosphate is also source of some hazardous elements, such: arsenic, cadmium, thorium and uranium, including a variety of radioisotopes as well. This radioactivity is sure to be released in the environment, contributing to the background. The risk is not recognized for some of the players in this market, mainly workers who apply phosphate fertilizers in the farmland, in some cases manipulating phosphates with their bare hands, and without any respiratory protection equipment (RPE) as well. This paper deals with the radioactivity from "2"2"6Ra and "2"2"8Ra in four phosphates often used in Brazilian agriculture. Three Brazilian and an Israeli phosphate were analysed and compared with international criteria. The specific activities of "2"2"6Ra (from the uranium decay series) and "2"2"8Ra (from the thorium decay series) were taken into consideration to ensure an adequate risk assessment. Specific activities were determined by high-resolution gamma spectroscopy with germanium detector and Genie® software from Canberra in the Centre of Nuclear Technology Development (CDTN/CNEN). The concentration of "2"2"6Ra was measured using the 186.2 keV energy peak, the concentration of "2"2"8Ra through "2"2"8Ac. The system was calibrated using a set of standard materials from IAEA. The measured samples were crushed and sieved to a grain (98% at least) size as small as 75 μm. Stable mass was achieved grinding, drying at 105°C and mixing