Crystallization and preliminary X-ray characterization of phosphoglucose isomerase from Mycobacterium tuberculosis H37Rv

International Nuclear Information System (INIS)

Mathur, Divya; Anand, Kanchan; Mathur, Deepika; Jagadish, Nirmala; Suri, Anil; Garg, Lalit C.

2007-01-01

The phosphoglucose isomerase from Mycobacterium tuberculosis H37Rv was crystallized and diffraction data were collected to 2.8 Å resolution. Phosphoglucose isomerase is a ubiquitous enzyme that catalyzes the isomerization of d-glucopyranose-6-phosphate to d-fructofuranose-6-phosphate. The present investigation reports the expression, purification, crystallization and preliminary crystallographic studies of the phosphoglucose isomerase from Mycobacterium tuberculosis H37Rv, which shares 46% sequence identity with that of its human host. The recombinant protein, which was prepared using an Escherichia coli expression system, was crystallized by the hanging-drop vapour-diffusion method. The crystals diffracted to a resolution of 2.8 Å and belonged to the orthorhombic space group I2 1 2 1 2 1 , with unit-cell parameters a = 109.0, b = 119.8, c = 138.9 Å

Discovery of ebselen as an inhibitor of Cryptosporidium parvum glucose-6-phosphate isomerase (CpGPI by high-throughput screening of existing drugs

Directory of Open Access Journals (Sweden)

Rana Eltahan

2018-04-01

Full Text Available Cryptosporidium parvum is a water-borne and food-borne apicomplexan pathogen. It is one of the top four diarrheal-causing pathogens in children under the age of five in developing countries, and an opportunistic pathogen in immunocompromised individuals. Unlike other apicomplexans, C. parvum lacks Kreb's cycle and cytochrome-based respiration, thus relying mainly on glycolysis to produce ATP. In this study, we characterized the primary biochemical features of the C. parvum glucose-6-phosphate isomerase (CpGPI and determined its Michaelis constant towards fructose-6-phosphate (Km = 0.309 mM, Vmax = 31.72 nmol/μg/min. We also discovered that ebselen, an organoselenium drug, was a selective inhibitor of CpGPI by high-throughput screening of 1200 known drugs. Ebselen acted on CpGPI as an allosteric noncompetitive inhibitor (IC50 = 8.33 μM; Ki = 36.33 μM, while complete inhibition of CpGPI activity was not achieved. Ebselen could also inhibit the growth of C. parvum in vitro (EC50 = 165 μM at concentrations nontoxic to host cells, albeit with a relatively small in vitro safety window of 4.2 (cytotoxicity TC50 on HCT-8 cells = 700 μM. Additionally, ebselen might also target other enzymes in the parasite, leading to the parasite growth reduction. Therefore, although ebselen is useful in studying the inhibition of CpGPI enzyme activity, further proof is needed to chemically and/or genetically validate CpGPI as a drug target. Keywords: Apicomplexan, Cryptosporidium parvum, Glucose-6-phosphate isomerase (GPI, Ebselen

Crystal structure of conjugated polyketone reductase (CPR-C1) from Candida parapsilosis IFO 0708 complexed with NADPH.

Science.gov (United States)

Qin, Hui-Min; Yamamura, Akihiro; Miyakawa, Takuya; Kataoka, Michihiko; Maruoka, Shintaro; Ohtsuka, Jun; Nagata, Koji; Shimizu, Sakayu; Tanokura, Masaru

2013-11-01

Conjugated polyketone reductase (CPR-C1) from Candida parapsilosis IFO 0708 is a member of the aldo-keto reductase (AKR) superfamily and reduces ketopantoyl lactone to d-pantoyl lactone in a NADPH-dependent and stereospecific manner. We determined the crystal structure of CPR-C1.NADPH complex at 2.20 Å resolution. CPR-C1 adopted a triose-phosphate isomerase (TIM) barrel fold at the core of the structure in which Thr25 and Lys26 of the GXGTX motif bind uniquely to the adenosine 2'-phosphate group of NADPH. This finding provides a novel structural basis for NADPH binding of the AKR superfamily. Copyright © 2013 Wiley Periodicals, Inc.

Triosephosphate isomerase: energetics of the reaction catalyzed by the yeast enzyme expressed in Escherichia coli

International Nuclear Information System (INIS)

Nickbarg, E.B.; Knowles, J.R.

1988-01-01

Triosephosphate isomerase from bakers' yeast, expressed in Escherichia coli strain DF502(p12), has been purified to homogeneity. The kinetics of the reaction in each direction have been determined at pH 7.5 and 30 degrees C. Deuterium substitution at the C-2 position of substrate (R)-glyceraldehyde phosphate and at the 1-pro-R position of substrate dihydroxyacetone phosphate results in kinetic isotope effects on kcat of 1.6 and 3.4, respectively. The extent of transfer of tritium from [1(R)- 3 H]dihydroxyacetone phosphate to product (R)-glyceraldehyde phosphate during the catalyzed reaction is only 3% after 66% conversion to product, indicating that the enzymic base that mediates proton transfer is in rapid exchange with solvent protons. When the isomerase-catalyzed reaction is run in tritiated water in each direction, radioactivity is incorporated both into the remaining substrate and into the product. In the exchange-conversion experiment with dihydroxyacetone phosphate as substrate, the specific radioactivity of remaining dihydroxyacetone phosphate rises as a function of the extent of reaction with a slope of about 0.3, while the specific radioactivity of the products is 54% that of the solvent. In the reverse direction with (R)-glyceraldehyde phosphate as substrate, the specific radioactivity of the product formed is only 11% that of the solvent, while the radioactivity incorporated into the remaining substrate (R)-glyceraldehyde phosphate also rises as a function of the extent of reaction with a slope of 0.3. These results have been analyzed according to the protocol described earlier to yield the free energy profile of the reaction catalyzed by the yeast isomerase

Bioproduction of D-Tagatose from D-Galactose Using Phosphoglucose Isomerase from Pseudomonas aeruginosa PAO1.

Science.gov (United States)

Patel, Manisha J; Patel, Arti T; Akhani, Rekha; Dedania, Samir; Patel, Darshan H

2016-07-01

Pseudomonas aeruginosa PAO1 phosphoglucose isomerase was purified as an active soluble form by a single-step purification using Ni-NTA chromatography that showed homogeneity on SDS-PAGE with molecular mass ∼62 kDa. The optimum temperature and pH for the maximum isomerization activity with D-galactose were 60 °C and 7.0, respectively. Generally, sugar phosphate isomerases show metal-independent activity but PA-PGI exhibited metal-dependent isomerization activity with aldosugars and optimally catalyzed the D-galactose isomerization in the presence of 1.0 mM MnCl2. The apparent Km and Vmax for D-galactose under standardized conditions were calculated to be 1029 mM (±31.30 with S.E.) and 5.95 U/mg (±0.9 with S.E.), respectively. Equilibrium reached after 180 min with production of 567.51 μM D-tagatose from 1000 mM of D-galactose. Though, the bioconversion ratio is low but it can be increased by immobilization and enzyme engineering. Although various L-arabinose isomerases have been characterized for bioproduction of D-tagatose, P. aeruginosa glucose phosphate isomerase is distinguished from the other L-arabinose isomerases by its optimal temperature (60 °C) for D-tagatose production being mesophilic bacteria, making it an alternate choice for bulk production.

Affinity labeling and characterization of the active site histidine of glucosephosphate isomerase

International Nuclear Information System (INIS)

Gibson, D.R.; Gracy, R.W.; Hartman, F.C.

1980-01-01

N-bromoacetylethanolamine phosphate was found to act as a specific affinity label for the active center of glucosephosphate isomerase. The inactivation process followed pseudo-first order kinetics, was irreversible, and exhibited rate saturation kinetics with minimal half-lives of inactivation of 4.5 and 6.3 min for the enzyme isolated from human placenta and rabbit muscle, respectively. The pH dependence of the inactivation process closely paralleled the pH dependence of the overall catalytic process with pK/sub a/ values at pH 6.4 and 9.0. The stoichiometry of labeling of either enzyme, as determined with N-bromo[ 14 C 2 ]acetylethanolamine phosphate, was 1 eq of the affinity label/subunit of enzyme. After acid hydrolysis and amino acid analysis of the radioactive affinity-labeled human enzyme, only radioactive 3-carboxymethyl histidine was found. In the case of the rabbit enzyme, the only radioactive derivative obtained was 1-carboxymethyl histidine. Active site tryptic peptides were isolated by solvent extraction, thin layer peptide fingerprinting, and ion exchange chromatography before and after removal of the phosphate from the active site peptide. Amino acid analysis of the labeled peptides from the two species were very similar. Using high sensitivity methods for sequence analysis, the primary structure of the active site was established as Val-Leu-His-Ala-Glu-Asn-Val-Asp (Gly,Thr,Ser) Glu-Ile (Thr-Gly-His-Lys-Glx)-Tyr-Phe. Apparent sequence homology between the catalytic center of glucosephosphate isomerase and triosephosphate isomerase suggest that the two enzymes may have evolved from a common ancestral gene

Genetics Home Reference: glucose phosphate isomerase deficiency

Science.gov (United States)

... glycolytic pathway; in this step, a molecule called glucose-6-phosphate is converted to another molecule called fructose-6-phosphate. When GPI remains a single molecule (a monomer) it is involved in the development and maintenance of nerve cells ( neurons ). In this context, it is often known as ...

Brønsted acid ionic liquid catalyzed formation of pyruvaldehyde dimethylacetal from triose sugars

DEFF Research Database (Denmark)

Shunmugavel, Saravanamurugan; Riisager, Anders

2013-01-01

A series of sulfonic acid functionalized ionic liquids (SO3H-ILs) have been synthesized, characterized and investigated as catalysts for the conversion of the triose sugars, 1,3-dihydroxyacetone (DHA) and glyceraldehyde (GLA), to pyruvaldehyde dimethylacetal (PADA) in methanol. Depending on the r......A series of sulfonic acid functionalized ionic liquids (SO3H-ILs) have been synthesized, characterized and investigated as catalysts for the conversion of the triose sugars, 1,3-dihydroxyacetone (DHA) and glyceraldehyde (GLA), to pyruvaldehyde dimethylacetal (PADA) in methanol. Depending...

Changes in cod muscle proteins during frozen storage revealed by proteome analysis and multivariate data analysis

DEFF Research Database (Denmark)

Kjærsgård, Inger Vibeke Holst; Nørrelykke, M.R.; Jessen, Flemming

2006-01-01

Multivariate data analysis has been combined with proteomics to enhance the recovery of information from 2-DE of cod muscle proteins during different storage conditions. Proteins were extracted according to 11 different storage conditions and samples were resolved by 2-DE. Data generated by 2-DE...... was subjected to principal component analysis (PCA) and discriminant partial least squares regression (DPLSR). Applying PCA to 2-DE data revealed the samples to form groups according to frozen storage time, whereas differences due to different storage temperatures or chilled storage in modified atmosphere...... light chain 1, 2 and 3, triose-phosphate isomerase, glyceraldehyde-3-phosphate dehydrogenase, aldolase A and two ?-actin fragments, and a nuclease diphosphate kinase B fragment to change in concentration, during frozen storage. Application of proteomics, multivariate data analysis and MS/MS to analyse...

Control analysis of the role of triosephosphate isomerase in glucose metabolism in Lactococcus lactis

DEFF Research Database (Denmark)

Solem, Christian; Købmann, Brian Jensen; Jensen, Peter Ruhdal

2008-01-01

Triosephosphate isomerase (TPI), which catalyses the conversion of dihydroxyacetone phosphate (DHAP) to glyceraldehyde-3-phosphate (G3P), was studied for its control on glycolysis and mixed acid production in L. lactis subspecies lactis IL1403 and L. lactis subspecies cremoris MG1363. Strains...... metabolites glucose-6-phosphate, fructose-1,6-bisphosphate and DHAP in the IL1403 derivatives were essentially unchanged for TPI activities from 26% to 225%. At a TPI activity of 3%, the level of DHAP increased four times. The finding that an increased level of DHAP coincides with an increase in formate...

Down-regulation of triose phosphate isomerase in Vineristine-resistant gastric cancer SGC7901 cell line identified by immobilized pH gradient two-dimensional gel electrophoresis and mierosequencing

Institute of Scientific and Technical Information of China (English)

无

2002-01-01

Objective:To exkplore new multidrug-resistance-related proteins in gastric SC7901 cells and clarify their mechanisms.Methods:Two-dimensional(2-D) polyacrylamide gel electrophoresis with immobilized pH gradients(IPG) was applied to compare the differential expression of multidrug-resistance-related proteins in gastric cancer SGC7901 cells and Vineristine-resistant SGC7901 cells (SGC7901/VCR) induced by vincristine sulfate.The 2-D gels were silver-stained.Then,preparative 2-D PAGE was performed.The differential proteins of PVDF membranes were cxcised and identified by N-terminal microsequencing.The mRNA expressions of differential proteins were detected in SGC 7901 cells and SGC7901/VCR cells by RT-PCR.Results:Approximatedly 680 protein sports were resolved on each 2-D gel by silver staining.Most protein spots showed no difference in composition,shape or density.25 proteins differed in abundance (6 higher in SGC7901/VCR cells;19 higher in 7901 cells);5 proteins were unique to one kind of cell or the othe(3 in SGC7901/VRC cells,2 in 7901 cells).One drug-resistance-related protein,which was down-regulated in SGC7901/VCR cells,was identified as trisephosphate isomerase(TPI),a glycolytic pathway enzyme.Conclusions:the results suggest that these differential proteins including TPI may be related to the Vincristine-resistant mechanism in human gastric cancer SGC7901/VCR cell line.

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

Directory of Open Access Journals (Sweden)

Cyril Moccand

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

Ribose catabolism of Escherichia coli: characterization of the rpiB gene encoding ribose phosphate isomerase B and of the rpiR gene, which is involved in regulation of rpiB expression

DEFF Research Database (Denmark)

Sørensen, Kim I.; Hove-Jensen, Bjarne

1996-01-01

. The rpiB gene resided on a 4.6-kbp HindIII-EcoRV DNA fragment from phage lambda 10H5 (642) of the Kohara gene library and mapped at 92.85 min. Consistent with this map position, the cloned DNA fragment contained two divergent open reading frames of 149 and 296 codons, encoding ribose phosphate isomerase B...

Investigation on the Metabolic Regulation of pgi gene knockout Escherichia coli by Enzyme Activities and Intracellular Metabolite Concentrations

Directory of Open Access Journals (Sweden)

Nor ‘Aini, A. R.

2006-01-01

Full Text Available An integrated analysis of the cell growth characteristics, enzyme activities, intracellular metabolite concentrations was made to investigate the metabolic regulation of pgi gene knockout Escherichia coli based on batch culture and continuous culture which was performed at the dilution rate of 0.2h-1. The enzymatic study identified that pathways of pentose phosphate, ED pathway and glyoxylate shunt were all active in pgi mutant. The glycolysis enzymes i.e glyceraldehyde-3-phosphate dehydrogenase, fructose diphosphatase, pyruvate kinase, triose phosphate isomerase were down regulated implying that the inactivation of pgi gene reduced the carbon flux through glycolytic pathway. Meanwhile, the pentose phosphate pathway was active as a major route for intermediary carbohydrate metabolism instead of glycolysis. The pentose phosphate pathway generates most of the major reducing co-factor NADPH as shown by the increased of NADPH/NADP+ ratio in the mutant when compared with the parent strain. The fermentative enzymes such as acetate kinase and lactate dehydrogenase were down regulated in the mutant. Knockout of pgi gene results in the significant increase in the intracellular concentration of glucose-6-phosphate and decrease in the concentration of oxaloacetate. The slow growth rate of the mutant was assumed to be affected by the accumulation of glucose-6-phosphate and imbalance of NADPH reoxidation.

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

Science.gov (United States)

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

2015-02-01

Leishmaniases are caused by protozoa of the genus Leishmania and are considered the second-highest cause of death worldwide by parasitic infection. The drugs available for treatment in humans are becoming ineffective mainly due to parasite resistance; therefore, it is extremely important to develop a new chemotherapy against these parasites. A crucial aspect of drug design development is the identification and characterization of novel molecular targets. In this work, through an in silico comparative analysis between the genomes of Leishmania major and Homo sapiens, the enzyme ribose 5-phosphate isomerase (R5PI) was indicated as a promising molecular target. R5PI is an important enzyme that acts in the pentose phosphate pathway and catalyzes the interconversion of d-ribose-5-phosphate (R5P) and d-ribulose-5-phosphate (5RP). R5PI activity is found in two analogous groups of enzymes called RpiA (found in H. sapiens) and RpiB (found in L. major). Here, we present the first report of the three-dimensional (3D) structures and active sites of RpiB from L. major (LmRpiB) and RpiA from H. sapiens (HsRpiA). Three-dimensional models were constructed by applying a hybrid methodology that combines comparative and ab initio modeling techniques, and the active site was characterized based on docking studies of the substrates R5P (furanose and ring-opened forms) and 5RP. Our comparative analyses show that these proteins are structural analogs and that distinct residues participate in the interconversion of R5P and 5RP. We propose two distinct reaction mechanisms for the reversible isomerization of R5P to 5RP, which is catalyzed by LmRpiB and HsRpiA. We expect that the present results will be important in guiding future molecular modeling studies to develop new drugs that are specially designed to inhibit the parasitic form of the enzyme without significant effects on the human analog. Copyright © 2014 Elsevier Inc. All rights reserved.

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

Distinguishing two types of gray mullet, Mugil cephalus L. (Mugiliformes: Mugilidae), by using glucose-6-phosphate isomerase (GPI) allozymes with special reference to enzyme activities.

Science.gov (United States)

Huang, C S; Weng, C F; Lee, S C

2001-06-01

The resident and migratory types of gray mullet, Mugil cephalus, on the coast of Taiwan can not be separated morphologically. Allozyme analysis was applied to estimate genetic variation between the two types of gray mullet and to test whether they belong to different populations. After starch gel electrophoresis, different allelic frequency spectra of glucose-6-phosphate isomerase-A (GPI-A) between stocks was observed. The resident stock contained Gpi-A(135) and Gpi-A(100), whereas the migratory type contained Gpi-A(100) only. In addition, GPI activities of locus A showed two distinct profiles between the two alleles. The results broadly revealed that Gpi-A allelic frequency was not regulated by temperature changes even after 6 months of thermal acclimation. This suggests that natural selection may play a role in shaping the allelic frequency change during the migratory journey. These findings suggest that the Gpi-A allelic difference can be used for population discrimination.

Glucose (xylose) isomerase production from thermotolerant and ...

African Journals Online (AJOL)

Owner

2012-11-13

Nov 13, 2012 ... in the production of the high fructose corn syrup (HFCS) from corn starch. ... Key words: Glucose isomerase, xylose isomerase, enzyme activity, Klebsiella, ... Soil, water, and manure (five samples each) were collected from.

Structure of conjugated polyketone reductase from Candida parapsilosis IFO 0708 reveals conformational changes for substrate recognition upon NADPH binding.

Science.gov (United States)

Qin, Hui-Min; Yamamura, Akihiro; Miyakawa, Takuya; Kataoka, Michihiko; Nagai, Takahiro; Kitamura, Nahoko; Urano, Nobuyuki; Maruoka, Shintaro; Ohtsuka, Jun; Nagata, Koji; Shimizu, Sakayu; Tanokura, Masaru

2014-01-01

Conjugated polyketone reductase C2 (CPR-C2) from Candida parapsilosis IFO 0708, identified as a nicotinamide adenine dinucleotide phosphate (NADPH)-dependent ketopantoyl lactone reductase, belongs to the aldo-keto reductase superfamily. This enzyme reduces ketopantoyl lactone to D-pantoyl lactone in a strictly stereospecific manner. To elucidate the structural basis of the substrate specificity, we determined the crystal structures of the apo CPR-C2 and CPR-C2/NADPH complex at 1.70 and 1.80 Å resolutions, respectively. CPR-C2 adopted a triose-phosphate isomerase barrel fold at the core of the structure. Binding with the cofactor NADPH induced conformational changes in which Thr27 and Lys28 moved 15 and 5.0 Å, respectively, in the close vicinity of the adenosine 2'-phosphate group of NADPH to form hydrogen bonds. Based on the comparison of the CPR-C2/NADPH structure with 3-α-hydroxysteroid dehydrogenase and mutation analyses, we constructed substrate binding models with ketopantoyl lactone, which provided insight into the substrate specificity by the cofactor-induced structure. The results will be useful for the rational design of CPR-C2 mutants targeted for use in the industrial manufacture of ketopantoyl lactone.

Discovery of ebselen as an inhibitor of Cryptosporidium parvum glucose-6-phosphate isomerase (CpGPI) by high-throughput screening of existing drugs.

Science.gov (United States)

Eltahan, Rana; Guo, Fengguang; Zhang, Haili; Xiang, Lixin; Zhu, Guan

2018-04-01

Cryptosporidium parvum is a water-borne and food-borne apicomplexan pathogen. It is one of the top four diarrheal-causing pathogens in children under the age of five in developing countries, and an opportunistic pathogen in immunocompromised individuals. Unlike other apicomplexans, C. parvum lacks Kreb's cycle and cytochrome-based respiration, thus relying mainly on glycolysis to produce ATP. In this study, we characterized the primary biochemical features of the C. parvum glucose-6-phosphate isomerase (CpGPI) and determined its Michaelis constant towards fructose-6-phosphate (K m  = 0.309 mM, V max  = 31.72 nmol/μg/min). We also discovered that ebselen, an organoselenium drug, was a selective inhibitor of CpGPI by high-throughput screening of 1200 known drugs. Ebselen acted on CpGPI as an allosteric noncompetitive inhibitor (IC 50  = 8.33 μM; K i  = 36.33 μM), while complete inhibition of CpGPI activity was not achieved. Ebselen could also inhibit the growth of C. parvum in vitro (EC 50  = 165 μM) at concentrations nontoxic to host cells, albeit with a relatively small in vitro safety window of 4.2 (cytotoxicity TC 50 on HCT-8 cells = 700 μM). Additionally, ebselen might also target other enzymes in the parasite, leading to the parasite growth reduction. Therefore, although ebselen is useful in studying the inhibition of CpGPI enzyme activity, further proof is needed to chemically and/or genetically validate CpGPI as a drug target. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

New procedures to measure synthase and phosphatase activities of bis-phosphoglycerate mutase. Interest for development of therapeutic drugs

International Nuclear Information System (INIS)

Ravel, P.; Garel, M.C.; Toullec, D.

1997-01-01

In red blood cells, a modulation of the level of the allosteric effector of hemoglobin, 2,3-diphosphoglycerate (2,3-DPG) would have implications in the treatment of ischemia and sickle cell anemia. Its concentrations is determined by the relative activities of the synthase and phosphatase reactions of the multifunctional bis-phosphoglycerate mutase (BPGM). In this report we develop first a more direct synthase assay which uses glyceraldehyde phosphate to suppress the aldolase and triose phosphate isomerase reactions. Secondly we propose a radioactive phosphatase assay coupled to chromatographic separation and identification of the reaction products by paper electrophoresis. Such identification of these products allows us to show that the multifunctional BPGM expresses its mutase instead of its phosphatase activity in conditions of competition between the 3-phosphoglycerate and the 2-phospho-glycolate activator in the phosphatase reaction. These two more precise procedures could be used to study the effects of substrate and cofactor analogues regarding potential therapeutic approaches and could be used for clinical analyses to detect deficiency of BPGM. (author)

Purification and characterization of the d-xylose isomerase gene from Escherichia coli

Energy Technology Data Exchange (ETDEWEB)

Ho, N W.Y.; Rosenfeld, S; Stevis, P; Tsao, G T

1983-11-01

A DNA fragment containing both the Escherichia coli D-xylose isomerase (D-xylose ketol-isomerase, EC 5.3.1.5) gene and the D-xylulokinase (ATP: D-xylulose 5-phosphotransferase, EC 2.7.1.17) gene has been cloned on an E. coli plasmid. The D-xylose isomerase gene was separated from the D-xylulokinase gene by the construction of a new deletion plasmid, pLX7. The D-xylose isomerase gene cloned on pLX7 was found still to be an intact gene. The precise location of the D-xylose isomerase gene on the plasmid pLX7 was further determined by the construction of two more plasmids, pLX8 and pLX9. This is believed to be the first D-xylose isomerase gene that has been isolated and extensively purified from any organism. D-Xylose isomerase, the enzyme product of the D-xylose isomerase gene, is responsible for the conversion of D-xylose to D-xylulose, as well as D-glucose to D-fructose. It is widely believed that yeast cannot ferment D-xylose to ethanol primarily because of the lack of D-xylose isomerase in yeast. D-Xylose isomerase (also known as D-glucose isomerase) is also used for the commercial production of high-fructose syrups. The purification of the D-xylose isomerase gene may lead to the following industrial applications: (1) cloning and expression of the gene in yeast to make the latter organism capable of directly fermenting D-xylose to ethanol, and (2) cloning of the gene on a high-copy-number plasmid in a proper host to overproduce the enzyme, which should have a profound impact on the high-fructose syrup technology. 14 references.

Construction of phosphomannose isomerase (PMI) transformation vectors and evaluation of the effectiveness of vectors in tobacco (Nicotiana tabacum L).

Science.gov (United States)

Bahariah, Bohari; Parveez, Ghulam Kadir Ahmad; Masani, Mat Yunus Abdul; Khalid, Norzulaani

2012-01-01

Phosphomannose isomerase (pmi) gene isolated from Escherichia coli allows transgenic plants carrying it to convert mannose-6- phosphate (from mannose), a carbon source that could not be naturally utilized by plants into fructose-6-phosphate which can be utilized by plants as a carbon source. This conversion ability provides energy source to allow the transformed cells to survive on the medium containing mannose. In this study, four transformation vectors carrying the pmi gene alone or in combination with the β-glucuronidase (gusA) gene were constructed and driven by either the maize ubiquitin (Ubi1) or the cauliflower mosaic virus (CaMV35S) promoter. Restriction digestion, PCR amplification and sequencing were carried out to ensure sequence integrity and orientation. Tobacco was used as a model system to study the effectiveness of the constructs and selection system. PMI11G and pMI3G, which carry gusA gene, were used to study the gene transient expression in tobacco. PMI3 construct, which only carries the pmi gene driven by CaMV35S promoter, was stably transformed into tobacco using biolistics after selection on 30 g 1(-1) mannose without sucrose. Transgenic plants were verified using PCR analysis. PMI/pmi - Phosphomannose isomerase, Ubi1 - Maize ubiquitin promoter, CaMV35S - Cauliflower mosaic virus 35S promoter, gusA - β-glucuronidase GUS reporter gene.

Aspects scanographiques de l'endométriose digestive: à propos de 11 cas

OpenAIRE

Paris , Marie

2000-01-01

Non disponible / Not available; L'endométriose digestive est une pathologie touchant les femmes en période d'activité génitale, et dont les localisations les plus fréquentes sont rectosigmoïdiennes. Elle est responsable d'épaississements pariétaux intestinaux à forte composante fibreuse, pouvant être sténosants. Le diagnostic en est souvent difficile, surtout lorsque la rythmicité des symptômes digestifs n'est pas évoquée, et en l'absence de la classique triade stérilité-dysménorrhée-dyspareu...

Molecular identification, immunolocalization, and characterization of Clonorchis sinensis triosephosphate isomerase.

Science.gov (United States)

Zhou, Juanjuan; Liao, Hua; Li, Shan; Zhou, Chenhui; Huang, Yan; Li, Xuerong; Liang, Chi; Yu, Xinbing

2015-08-01

Clonorchis sinensis triosephosphate isomerase (CsTIM) is a key regulatory enzyme of glycolysis and gluconeogenesis, which catalyzes the interconversion of glyceraldehyde 3-phosphate to dihydroxyacetone phosphate. In this study, the biochemical characterizations of CsTIM have been examined. A full-length complementary DNA (cDNA; Cs105350) sequence encoding CsTIM was obtained from our C. sinensis cDNA library. The open reading frame of CsTIM contains 759 bp which encodes 252 amino acids. The amino acid sequence of CsTIM shares 60-65% identity with other species. Western blot analysis displayed that recombinant CsTIM (rCsTIM) can be probed by anti-rCsTIM rat serum and anti-C. sinensis excretory/secretory products (anti-CsESPs) rat serum. Quantitative reverse transcription (RT)-PCR and western blotting analysis revealed that CsTIM messenger RNA (mRNA) and protein were differentially expressed in development cycle stages of the parasite, including adult worm, metacercaria, excysted metacercaria, and egg. In addition, immunolocalization assay showed that CsTIM was located in the seminal vesicle, eggs, and testicle. Moreover, rCsTIM exhibited active enzyme activity in catalytic reactions. The Michaelis constant (K m) of rCsTIM was 0.33 mM, when using glyceraldehyde 3-phosphate as the substrate. The optimal temperature and pH of CsTIM were 37 °C and 7.5-9.5, respectively. Collectively, these results suggest that CsTIM is an important protein involved in glycometabolism, and CsTIM possibly take part in many biological functions in the growth and development of C. sinensis.

A single and two step isomerization process for d-tagatose and l-ribose bioproduction using l-arabinose isomerase and d-lyxose isomerase.

Science.gov (United States)

Patel, Manisha J; Akhani, Rekha C; Patel, Arti T; Dedania, Samir R; Patel, Darshan H

2017-02-01

l-ribose and d-tagatose are biochemically synthesized using sugar isomerases. The l-arabinose isomerase gene from Shigella flexneri (Sf-AI) was cloned and expressed in Escherichia coli BL-21. Sf-AI was applied for the bioproduction of d-tagatose from d-galactose. l-ribose synthesis was performed by two step isomerization using Sf-AI and d-lyxose/ribose isomerase from Cohnella laevoribosii. The overall 22.3% and 25% conversion rate were observed for d-tagatose and l-ribose production from d-galactose and l-arabinose respectively. In the present manuscript, synthesis of rare sugars from naturally available sugars is discussed along with the biochemical characterization of Sf-AI and its efficiency. Copyright © 2016 Elsevier Inc. All rights reserved.

An operon encoding three glycolytic enzymes in Lactobacillus delbrueckii subsp. bulgaricus: glyceraldehyde-3-phosphate dehydrogenase, phosphoglycerate kinase and triosephosphate isomerase.

Science.gov (United States)

Branny, P; de la Torre, F; Garel, J R

1998-04-01

The structural genes gap, pgk and tpi encoding three glycolytic enzymes, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), 3-phosphoglycerate kinase (PGK) and triosephosphate isomerase (TPI), respectively, have been cloned and sequenced from Lactobacillus delbrueckii subsp. bulgaricus (L. bulgaricus). The genes were isolated after screening genomic sublibraries with specific gap and pgk probes obtained by PCR amplification of chromosomal DNA with degenerate primers corresponding to amino acid sequences highly conserved in GAPDHs and PGKs. Nucleotide sequencing revealed that the three genes were organized in the order gap-pgk-tpi. The translation start codons of the three genes were identified by alignment of the N-terminal sequences. These genes predicted polypeptide chains of 338, 403 and 252 amino acids for GAPDH, PGK and TPI, respectively, and they were separated by 96 bp between gap and pgk, and by only 18 bp between pgk and tpi. The codon usage in gap, pgk, tpi and three other glycolytic genes from L. bulgaricus differed, noticeably from that in other chromosomal genes. The site of transcriptional initiation was located by primer extension, and a probable promoter was identified for the gap-pgk-tpi operon. Northern hybridization of total RNA with specific probes showed two transcripts, an mRNA of 1.4 kb corresponding to the gap gene, and a less abundant mRNA of 3.4 kb corresponding to the gap-pgk-tpi cluster. The absence of a visible terminator in the 3'-end of the shorter transcript and the location of this 3'-end inside the pgk gene indicated that this shorter transcript was produced by degradation of the longer one, rather than by an early termination of transcription after the gap gene.

L'endométriose de la paroi abdominale: à propos d'un cas rare

Science.gov (United States)

Jayi, Sofia; Laadioui, Meriem; Bouguern, Hakima; Chaara, Hikmat; Melhouf, Aabdelilah

2013-01-01

L'endométriose de la paroi est une entité clinique rare, dont la physiopathologie demeure imprécise. Elle survient le plus souvent après une intervention chirurgicale gynécologique ou obstétricale. Nous rapportons le cas d'une patiente présentant une douleur cyclique, au niveau de la cicatrice de césarienne. Avec à l'examen clinique une masse de 3 cm localisée au niveau de la fosse iliaque droite. L'échographie-doppler a objectivé une image d'allure tissulaire, polylobée, à vascularisation centrale, mesurant 32/16 mm, évoquent une masse endométriosique ou une tumeur des parties molles. D'où la décision d'excision de la lésion, au cours de laquelle on a découvert une masse dure de 3/2 cm, en sous aponévrotique accolée au muscle grand droit de l'abdomen. L'étude anatomopathologique a confirmé le diagnostic d'endométriose pariétale. Les suites postopératoires étaient simples avec un recul de 2 ans et demie sans récidive de la masse ni de la douleur. A travers notre cas, nous insisterons sur les caractéristiques de cette pathologie notamment pronostic, ce qui permettra au praticien de comprendre l'intérêt du diagnostic et prise en charge précoce de cette entité - pour laquelle on ne pense jamais assez devant une masse pariétale - et de sa prévention au cours de chaque chirurgie gynécologique ou obstétricale. PMID:24171068

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

Triosephosphate isomerase is a common crystallization contaminant of soluble His-tagged proteins produced in Escherichia coli

International Nuclear Information System (INIS)

Kozlov, Guennadi; Vinaik, Roohi; Gehring, Kalle

2013-01-01

Crystals of E. coli triosephosphate isomerase were obtained as a contaminant and its structure was determined to 1.85 Å resolution. Attempts to crystallize several mammalian proteins overexpressed in Escherichia coli revealed a common contaminant, triosephosphate isomerase, a protein involved in glucose metabolism. Even with triosephosphate isomerase present in very small amounts, similarly shaped crystals appeared in the crystallization drops in a number of polyethylene glycol-containing conditions. All of the target proteins were His-tagged and their purification involved immobilized metal-affinity chromatography (IMAC), a step that was likely to lead to triosephosphate isomerase contamination. Analysis of the triosephosphate isomerase crystals led to the structure of E. coli triosephosphate isomerase at 1.85 Å resolution, which is a significant improvement over the previous structure

Immobilization of Recombinant Glucose Isomerase for Efficient Production of High Fructose Corn Syrup.

Science.gov (United States)

Jin, Li-Qun; Xu, Qi; Liu, Zhi-Qiang; Jia, Dong-Xu; Liao, Cheng-Jun; Chen, De-Shui; Zheng, Yu-Guo

2017-09-01

Glucose isomerase is the important enzyme for the production of high fructose corn syrup (HFCS). One-step production of HFCS containing more than 55% fructose (HFCS-55) is receiving much attention for its industrial applications. In this work, the Escherichia coli harboring glucose isomerase mutant TEGI-W139F/V186T was immobilized for efficient production of HFCS-55. The immobilization conditions were optimized, and the maximum enzyme activity recovery of 92% was obtained. The immobilized glucose isomerase showed higher pH, temperature, and operational stabilities with a K m value of 272 mM and maximum reaction rate of 23.8 mM min -1 . The fructose concentration still retained above 55% after the immobilized glucose isomerase was reused for 10 cycles, and more than 85% of its initial activity was reserved even after 15 recycles of usage at temperature of 90 °C. The results highlighted the immobilized glucose isomerase as a potential biocatalyst for HFCS-55 production.

Multifaceted roles of metabolic enzymes of the Paracoccidioides species complex

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Caroline Maria Marcos

2014-12-01

Full Text Available Paracoccidioides species are dimorphic fungi, and are the etiologic agents of paracoccidioidomycosis (PCM, a serious disease of multiple organs. The large number of tissues colonized by this fungus suggests the presence of a variety of surface molecules involved in adhesion. A surprising finding is that the majority of enzymes in the glycolytic pathway, tricarboxylic acid (TCA cycle and glyoxylate cycle in Paracoccidioides spp. has adhesive properties that aid in the interaction with the host extracellular matrix, and so act as ‘moonlighting’ proteins. Moonlighting proteins have multiple functions and add another dimension to cellular complexity, while benefiting cells in several ways. This phenomenon occurs in both eukaryotes and prokaryotes. For example, moonlighting proteins from the glycolytic pathway or TCA cycle can play roles in bacterial pathogens, either by acting as proteins secreted in a conventional pathway or not and/or as cell surface component that facilitate adhesion or adherence . This review outlines the multifuncionality exposed by a variety of Paracoccidioides spp. enzymes including aconitase, aldolase, glyceraldehyde-3-phosphate dehydrogenase, isocitrate lyase, malate synthase, triose phosphate isomerase, fumarase and enolase. The roles that moonlighting activities play in the virulence characteristics of this fungus and several other human pathogens during their interactions with the host are discussed.

L'endométriose pariétale cicatricielle après césarienne: une entité rare

Science.gov (United States)

El Fahssi, Mohammed; Lomdo, Massama; Bounaim, Ahmed; Ali, Abdelmounaim Ait; Sair, Khalid

2016-01-01

L'endométriose de la paroi est une entité clinique rare, dont la physiopathologie demeure imprécise. Elle survient le plus souvent après une intervention chirurgicale gynécologique ou obstétricale. Nous rapportons le cas d'une patiente présentant une douleur cyclique, au niveau de la cicatrice de césarienne, Avec à l'examen clinique une masse de 5cm localisée au niveau de la fosse iliaque droite. la tomodensitométrie montre une masse de densité tissulaire de 45mm de grand axe. D'où la décision d'excision large de la lésion dont l’étude anatomopathologique confirme le diagnostic d'endométriose pariétale. Les suites postopératoires étaient simples avec un recul de 20 mois sans récidive de la masse ni de la douleur. A travers notre cas, nous insisterons sur les caractéristiques de cette pathologie, ce qui permettra au praticien de comprendre l'intérêt du diagnostic et de la prise en charge précoce de cette affection ainsi que la possibilité de sa prévention au cours de chaque chirurgie gynécologique ou obstétricale. PMID:27642418

Neurological findings in triosephosphate isomerase deficiency

NARCIS (Netherlands)

Poll-The, B. T.; Aicardi, J.; Girot, R.; Rosa, R.

1985-01-01

Two siblings with hemolytic anemia caused by triosephosphate isomerase deficiency developed a progressive neurological syndrome featuring dystonic movements, tremor, pyramidal tract signs, and evidence of spinal motor neuron involvement. Intelligence was unaffected. The findings in these patients

Using intron sequence comparisons in the triose-phosphate isomerase gene to study the divergence of the fall armyworm host strains

Science.gov (United States)

The Noctuid moth, Spodoptera frugiperda (the fall armyworm), is endemic to the Western Hemisphere and appears to be undergoing sympatric speciation to produce two subpopulations that differ in their choice of host plants. The diverging “rice strain” and “corn strain” are morphologically indistinguis...

Overexpression, purification, crystallization and preliminary X-ray crystal analysis of Bacillus pallidusd-arabinose isomerase

International Nuclear Information System (INIS)

Takeda, Kosei; Yoshida, Hiromi; Takada, Goro; Izumori, Ken; Kamitori, Shigehiro

2008-01-01

Recombinant B. pallidusd-arabinose isomerase was crystallized and diffraction data were collected to 2.3 Å resolution. d-Arabinose isomerase catalyzes the isomerization of d-arabinose to d-ribulose. Bacillus pallidusd-arabinose isomerase has broad substrate specificity and can catalyze the isomerization of d-arabinose, l-fucose, l-xylose, l-galactose and d-altrose. Recombinant B. pallidusd-arabinose isomerase was overexpressed, purified and crystallized. A crystal of the enzyme was obtained by the sitting-drop method at room temperature and belonged to the orthorhombic space group P2 1 2 1 2, with unit-cell parameters a = 144.9, b = 127.9, c = 109.5 Å. Diffraction data were collected to 2.3 Å resolution

Polyphyly and gene flow between non-sibling Heliconius species

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Jiggins Chris D

2006-04-01

Full Text Available Abstract Background The view that gene flow between related animal species is rare and evolutionarily unimportant largely antedates sensitive molecular techniques. Here we use DNA sequencing to investigate a pair of morphologically and ecologically divergent, non-sibling butterfly species, Heliconius cydno and H. melpomene (Lepidoptera: Nymphalidae, whose distributions overlap in Central and Northwestern South America. Results In these taxa, we sequenced 30–45 haplotypes per locus of a mitochondrial region containing the genes for cytochrome oxidase subunits I and II (CoI/CoII, and intron-spanning fragments of three unlinked nuclear loci: triose-phosphate isomerase (Tpi, mannose-6-phosphate isomerase (Mpi and cubitus interruptus (Ci genes. A fifth gene, dopa decarboxylase (Ddc produced sequence data likely to be from different duplicate loci in some of the taxa, and so was excluded. Mitochondrial and Tpi genealogies are consistent with reciprocal monophyly, whereas sympatric populations of the species in Panama share identical or similar Mpi and Ci haplotypes, giving rise to genealogical polyphyly at the species level despite evidence for rapid sequence divergence at these genes between geographic races of H. melpomene. Conclusion Recent transfer of Mpi haplotypes between species is strongly supported, but there is no evidence for introgression at the other three loci. Our results demonstrate that the boundaries between animal species can remain selectively porous to gene flow long after speciation, and that introgression, even between non-sibling species, can be an important factor in animal evolution. Interspecific gene flow is demonstrated here for the first time in Heliconius and may provide a route for the transfer of switch-gene adaptations for Müllerian mimicry. The results also forcefully demonstrate how reliance on a single locus may give an erroneous picture of the overall genealogical history of speciation and gene flow.

Screening and selection of wild strains for L-arabinose isomerase production

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R. M. Manzo

2013-12-01

Full Text Available The majority of L-arabinose isomerases have been isolated by recombinant techniques, but this methodology implies a reduced technological application. For this reason, 29 bacterial strains, some of them previously characterized as L-arabinose isomerase producers, were assayed as L-arabinose fermenting strains by employing conveniently designed culture media with 0.5% (w/v L-arabinose as main carbon source. From all evaluated bacterial strains, Enterococcus faecium DBFIQ ID: E36, Enterococcus faecium DBFIQ ID: ETW4 and Pediococcus acidilactici ATCC ID: 8042 were, in this order, the best L-arabinose fermenting strains. Afterwards, to assay L-arabinose metabolization and L-arabinose isomerase activity, cell-free extract and saline precipitated cell-free extract of the three bacterial cultures were obtained and the production of ketoses was determined by the cysteine carbazole sulfuric acid method. Results showed that the greater the L-arabinose metabolization ability, the higher the enzymatic activity achieved, so Enterococcus faecium DBFIQ ID: E36 was selected to continue with production, purification and characterization studies. This work thus describes a simple microbiological method for the selection of L-arabinose fermenting bacteria for the potential production of the enzyme L-arabinose isomerase.

Metabolic engineering for high glycerol production by the anaerobic cultures of Saccharomyces cerevisiae.

Science.gov (United States)

Semkiv, Marta V; Dmytruk, Kostyantyn V; Abbas, Charles A; Sibirny, Andriy A

2017-06-01

Glycerol is used by the cosmetic, paint, automotive, food, and pharmaceutical industries and for production of explosives. Currently, glycerol is available in commercial quantities as a by-product from biodiesel production, but the purity and the cost of its purification are prohibitive. The industrial production of glycerol by glucose aerobic fermentation using osmotolerant strains of the yeasts Candida sp. and Saccharomyces cerevisiae has been described. A major drawback of the aerobic process is the high cost of production. For this reason, the development of yeast strains that effectively convert glucose to glycerol anaerobically is of great importance. Due to its ability to grow under anaerobic conditions, the yeast S. cerevisiae is an ideal system for the development of this new biotechnological platform. To increase glycerol production and accumulation from glucose, we lowered the expression of TPI1 gene coding for triose phosphate isomerase; overexpressed the fused gene consisting the GPD1 and GPP2 parts coding for glycerol-3-phosphate dehydrogenase and glycerol-3-phosphate phosphatase, respectively; overexpressed the engineered FPS1 gene that codes for aquaglyceroporin; and overexpressed the truncated gene ILV2 that codes for acetolactate synthase. The best constructed strain produced more than 20 g of glycerol/L from glucose under micro-aerobic conditions and 16 g of glycerol/L under anaerobic conditions. The increase in glycerol production led to a drop in ethanol and biomass accumulation.

Xylose isomerase improves growth and ethanol production rates from biomass sugars for both Saccharomyces pastorianus and Saccharomyces cerevisiae.

Science.gov (United States)

Miller, Kristen P; Gowtham, Yogender Kumar; Henson, J Michael; Harcum, Sarah W

2012-01-01

The demand for biofuel ethanol made from clean, renewable nonfood sources is growing. Cellulosic biomass, such as switch grass (Panicum virgatum L.), is an alternative feedstock for ethanol production; however, cellulosic feedstock hydrolysates contain high levels of xylose, which needs to be converted to ethanol to meet economic feasibility. In this study, the effects of xylose isomerase on cell growth and ethanol production from biomass sugars representative of switch grass were investigated using low cell density cultures. The lager yeast species Saccharomyces pastorianus was grown with immobilized xylose isomerase in the fermentation step to determine the impact of the glucose and xylose concentrations on the ethanol production rates. Ethanol production rates were improved due to xylose isomerase; however, the positive effect was not due solely to the conversion of xylose to xylulose. Xylose isomerase also has glucose isomerase activity, so to better understand the impact of the xylose isomerase on S. pastorianus, growth and ethanol production were examined in cultures provided fructose as the sole carbon. It was observed that growth and ethanol production rates were higher for the fructose cultures with xylose isomerase even in the absence of xylose. To determine whether the positive effects of xylose isomerase extended to other yeast species, a side-by-side comparison of S. pastorianus and Saccharomyces cerevisiae was conducted. These comparisons demonstrated that the xylose isomerase increased ethanol productivity for both the yeast species by increasing the glucose consumption rate. These results suggest that xylose isomerase can contribute to improved ethanol productivity, even without significant xylose conversion. Copyright © 2012 American Institute of Chemical Engineers (AIChE).

21 CFR 862.1570 - Phosphohexose isomerase test system.

Science.gov (United States)

2010-04-01

.... Measurements of phosphohexose isomerase are used in the diagnosis and treatment of muscle diseases such as muscular dystrophy, liver diseases such as hepatitis or cirrhosis, and metastatic carcinoma. (b...

The secreted l-arabinose isomerase displays anti-hyperglycemic effects in mice

OpenAIRE

Rhimi, Moez; Bermudez-Humaran, Luis G.; Huang, Yuan; Boudebbouze, Samira; Gaci, Nadia; Garnier, Alexandrine; Gratadoux, Jean-Jacques; Mkaouar, H?la; Langella, Philippe; Maguin, Emmanuelle

2015-01-01

Background The l-arabinose isomerase is an intracellular enzyme which converts l-arabinose into l-ribulose in living systems and d-galactose into d-tagatose in industrial processes and at industrial scales. d-tagatose is a natural ketohexose with potential uses in pharmaceutical and food industries. The d-galactose isomerization reaction is thermodynamically equilibrated, and leads to secondary subproducts at high pH. Therefore, an attractive l-arabinose isomerase should be thermoactive and a...

L-Arabinose isomerase and its use for biotechnological production of rare sugars.

Science.gov (United States)

Xu, Zheng; Li, Sha; Feng, Xiaohai; Liang, Jinfeng; Xu, Hong

2014-11-01

L-Arabinose isomerase (AI), a key enzyme in the microbial pentose phosphate pathway, has been regarded as an important biological catalyst in rare sugar production. This enzyme could isomerize L-arabinose into L-ribulose, as well as D-galactose into D-tagatose. Both the two monosaccharides show excellent commercial values in food and pharmaceutical industries. With the identification of novel AI family members, some of them have exhibited remarkable potential in industrial applications. The biological production processes for D-tagatose and L-ribose (or L-ribulose) using AI have been developed and improved in recent years. Meanwhile, protein engineering techniques involving rational design has effectively enhanced the catalytic properties of various AIs. Moreover, the crystal structure of AI has been disclosed, which sheds light on the understanding of AI structure and catalytic mechanism at molecular levels. This article reports recent developments in (i) novel AI screening, (ii) AI-mediated rare sugar production processes, (iii) molecular modification of AI, and (iv) structural biology study of AI. Based on previous reports, an analysis of the future development has also been initiated.

Preparation of fluorescence quenched libraries containing interchain disulphide bonds for studies of protein disulphide isomerases

DEFF Research Database (Denmark)

Spetzler, J C; Westphal, V; Winther, Jakob R.

1998-01-01

Protein disulphide isomerase is an enzyme that catalyses disulphide redox reactions in proteins. In this paper, fluorogenic and interchain disulphide bond containing peptide libraries and suitable substrates, useful in the study of protein disulphide isomerase, are described. In order to establish...... the quenching chromophore (Tyr(NO2)) and Cys(pNpys) activated for reaction with a second thiol. The formation and cleavage of the interchain disulphide bonds in the library were monitored under a fluorescence microscope. Substrates to investigate the properties of protein disulphide isomerase in solution were...

Functional differences in yeast protein disulfide isomerases

DEFF Research Database (Denmark)

Nørgaard, P; Westphal, V; Tachibana, C

2001-01-01

PDI1 is the essential gene encoding protein disulfide isomerase in yeast. The Saccharomyces cerevisiae genome, however, contains four other nonessential genes with homology to PDI1: MPD1, MPD2, EUG1, and EPS1. We have investigated the effects of simultaneous deletions of these genes. In several...

Comparing the xylose reductase/xylitol dehydrogenase and xylose isomerase pathways in arabinose and xylose fermenting Saccharomyces cerevisiae strains

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Hahn-Hägerdal Bärbel

2008-10-01

Full Text Available Abstract Background Ethanolic fermentation of lignocellulosic biomass is a sustainable option for the production of bioethanol. This process would greatly benefit from recombinant Saccharomyces cerevisiae strains also able to ferment, besides the hexose sugar fraction, the pentose sugars, arabinose and xylose. Different pathways can be introduced in S. cerevisiae to provide arabinose and xylose utilisation. In this study, the bacterial arabinose isomerase pathway was combined with two different xylose utilisation pathways: the xylose reductase/xylitol dehydrogenase and xylose isomerase pathways, respectively, in genetically identical strains. The strains were compared with respect to aerobic growth in arabinose and xylose batch culture and in anaerobic batch fermentation of a mixture of glucose, arabinose and xylose. Results The specific aerobic arabinose growth rate was identical, 0.03 h-1, for the xylose reductase/xylitol dehydrogenase and xylose isomerase strain. The xylose reductase/xylitol dehydrogenase strain displayed higher aerobic growth rate on xylose, 0.14 h-1, and higher specific xylose consumption rate in anaerobic batch fermentation, 0.09 g (g cells-1 h-1 than the xylose isomerase strain, which only reached 0.03 h-1 and 0.02 g (g cells-1h-1, respectively. Whereas the xylose reductase/xylitol dehydrogenase strain produced higher ethanol yield on total sugars, 0.23 g g-1 compared with 0.18 g g-1 for the xylose isomerase strain, the xylose isomerase strain achieved higher ethanol yield on consumed sugars, 0.41 g g-1 compared with 0.32 g g-1 for the xylose reductase/xylitol dehydrogenase strain. Anaerobic fermentation of a mixture of glucose, arabinose and xylose resulted in higher final ethanol concentration, 14.7 g l-1 for the xylose reductase/xylitol dehydrogenase strain compared with 11.8 g l-1 for the xylose isomerase strain, and in higher specific ethanol productivity, 0.024 g (g cells-1 h-1 compared with 0.01 g (g cells-1 h-1

Characterization of a mutated Geobacillus stearothermophilus L-arabinose isomerase that increases the production rate of D-tagatose.

Science.gov (United States)

Kim, H-J; Kim, J-H; Oh, H-J; Oh, D-K

2006-07-01

Characterization of a mutated Geobacillus stearothermophilus L-arabinose isomerase used to increase the production rate of D-tagatose. A mutated gene was obtained by an error-prone polymerase chain reaction using L-arabinose isomerase gene from G. stearothermophilus as a template and the gene was expressed in Escherichia coli. The expressed mutated L-arabinose isomerase exhibited the change of three amino acids (Met322-->Val, Ser393-->Thr, and Val408-->Ala), compared with the wild-type enzyme and was then purified to homogeneity. The mutated enzyme had a maximum galactose isomerization activity at pH 8.0, 65 degrees C, and 1.0 mM Co2+, while the wild-type enzyme had a maximum activity at pH 8.0, 60 degrees C, and 1.0-mM Mn2+. The mutated L-arabinose isomerase exhibited increases in D-galactose isomerization activity, optimum temperature, catalytic efficiency (kcat/Km) for D-galactose, and the production rate of D-tagatose from D-galactose. The mutated L-arabinose isomerase from G. stearothermophilus is valuable for the commercial production of D-tagatose. This work contributes knowledge on the characterization of a mutated L-arabinose isomerase, and allows an increased production rate for D-tagatose from D-galactose using the mutated enzyme.

Proteomic and biochemical basis for enhanced growth yield of Enterobacter sp. LCR1 on insoluble phosphate medium.

Science.gov (United States)

Kumar, Arvind; Rai, Lal Chand

2015-01-01

Proteomics and biochemical analyses were used to unravel the basis for higher growth yield of Enterobacter sp. LCR1 on insoluble phosphate medium compared to soluble. Proteomic analysis using 2-DE, MALDI-TOF/MS and LC-MS revealed the involvement of nine proteins. Down-regulation of fructose bisphosphate aldolase with decreased concentrations of glucose-6-phosphate and fructose-6-phosphate indicated diminished glycolysis. However, up-regulation of phosphoglycerate mutase, increase in the activities of 6-phosphogluconate dehydratase, 2-keto-3-deoxy-6-phosphogluconate aldolase and 6-phosphogluconate dehydrogenase suggested induction of Entner-Doudoroff and pentose phosphate pathways. These pathways generate sufficient energy from gluconic acid, which is also used for biosynthesis as indicated by up-regulation of elongation factor Tu, elongation factor G and protein disulfide isomerase. Increased reactive oxygen species (ROS) formation resulting from organic acid oxidation leads to overexpressed manganese superoxide dismutase and increased activities of catalase and ascorbate peroxidase. Thus the organism uses gluconate instead of glucose for energy, while alleviating extra ROS formation by oxidative defense enzymes. Copyright © 2014 Elsevier GmbH. All rights reserved.

Changes in muscle cell metabolism and mechanotransduction are associated with myopathic phenotype in a mouse model of collagen VI deficiency.

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Sara De Palma

Full Text Available This study identifies metabolic and protein phenotypic alterations in gastrocnemius, tibialis anterior and diaphragm muscles of Col6a1(-/- mice, a model of human collagen VI myopathies. All three muscles of Col6a1(-/- mice show some common changes in proteins involved in metabolism, resulting in decreased glycolysis and in changes of the TCA cycle fluxes. These changes lead to a different fate of α-ketoglutarate, with production of anabolic substrates in gastrocnemius and tibialis anterior, and with lipotoxicity in diaphragm. The metabolic changes are associated with changes of proteins involved in mechanotransduction at the myotendineous junction/costameric/sarcomeric level (TN-C, FAK, ROCK1, troponin I fast and in energy metabolism (aldolase, enolase 3, triose phosphate isomerase, creatine kinase, adenylate kinase 1, parvalbumin, IDH1 and FASN. Together, these change may explain Ca(2+ deregulation, impaired force development, increased muscle-relaxation-time and fiber damage found in the mouse model as well as in patients. The severity of these changes differs in the three muscles (gastrocnemius

Structural and Thermodynamic Insights into Chitooligosaccharide Binding to Human Cartilage Chitinase 3-like Protein 2 (CHI3L2 or YKL-39)*

Science.gov (United States)

Ranok, Araya; Wongsantichon, Jantana; Robinson, Robert C.; Suginta, Wipa

2015-01-01

Four crystal structures of human YKL-39 were solved in the absence and presence of chitooligosaccharides. The structure of YKL-39 comprises a major (β/α)8 triose-phosphate isomerase barrel domain and a small α + β insertion domain. Structural analysis demonstrates that YKL-39 interacts with chitooligosaccharides through hydrogen bonds and hydrophobic interactions. The binding of chitin fragments induces local conformational changes that facilitate tight binding. Compared with other GH-18 members, YKL-39 has the least extended chitin-binding cleft, containing five subsites for sugars, namely (−3)(−2)(−1)(+1)(+2), with Trp-360 playing a prominent role in the sugar-protein interactions at the center of the chitin-binding cleft. Evaluation of binding affinities obtained from isothermal titration calorimetry and intrinsic fluorescence spectroscopy suggests that YKL-39 binds to chitooligosaccharides with Kd values in the micromolar concentration range and that the binding energies increase with the chain length. There were no significant differences between the Kd values of chitopentaose and chitohexaose, supporting the structural evidence for the five binding subsite topology. Thermodynamic analysis indicates that binding of chitooligosaccharide to YKL-39 is mainly driven by enthalpy. PMID:25477513

A Practical Quantum Mechanics Molecular Mechanics Method for the Dynamical Study of Reactions in Biomolecules.

Science.gov (United States)

Mendieta-Moreno, Jesús I; Marcos-Alcalde, Iñigo; Trabada, Daniel G; Gómez-Puertas, Paulino; Ortega, José; Mendieta, Jesús

2015-01-01

Quantum mechanics/molecular mechanics (QM/MM) methods are excellent tools for the modeling of biomolecular reactions. Recently, we have implemented a new QM/MM method (Fireball/Amber), which combines an efficient density functional theory method (Fireball) and a well-recognized molecular dynamics package (Amber), offering an excellent balance between accuracy and sampling capabilities. Here, we present a detailed explanation of the Fireball method and Fireball/Amber implementation. We also discuss how this tool can be used to analyze reactions in biomolecules using steered molecular dynamics simulations. The potential of this approach is shown by the analysis of a reaction catalyzed by the enzyme triose-phosphate isomerase (TIM). The conformational space and energetic landscape for this reaction are analyzed without a priori assumptions about the protonation states of the different residues during the reaction. The results offer a detailed description of the reaction and reveal some new features of the catalytic mechanism. In particular, we find a new reaction mechanism that is characterized by the intramolecular proton transfer from O1 to O2 and the simultaneous proton transfer from Glu 165 to C2. Copyright © 2015 Elsevier Inc. All rights reserved.

Diversity of antisense and other non-coding RNAs in Archaea revealed by comparative small RNA sequencing in four Pyrobaculum species

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David L Bernick

2012-07-01

Full Text Available A great diversity of small, non-coding RNA molecules with roles in gene regulation and RNA processing have been intensely studied in eukaryotic and bacterial model organisms, yet our knowledge of possible parallel roles for small RNAs in archaea is limited. We employed RNA-seq to identify novel small RNA across multiple species of the hyperthermophilic genus Pyrobaculum, known for unusual RNA gene characteristics. By comparing transcriptional data collected in parallel among four species, we were able to identify conserved RNA genes fitting into known and novel families. Among our findings, we highlight three novel cis-antisense small RNAs encoded opposite to key regulatory (ferric uptake regulator, metabolic (triose-phosphate isomerase, and core transcriptional apparatus genes (transcription factor B. We also found a large increase in the number of conserved C/D box small RNA genes over what had been previously recognized; many of these genes are encoded antisense to protein coding genes. The conserved opposition to orthologous genes across the Pyrobaculum genus suggests similarities to other cis-antisense regulatory systems. Furthermore, the genus-specific nature of these small RNAs indicates they are relatively recent, stable adaptations.

Comparative proteomics of extracellular proteins in vitro and in planta from the pathogenic fungus Fusarium graminearum.

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Paper, Janet M; Scott-Craig, John S; Adhikari, Neil D; Cuomo, Christina A; Walton, Jonathan D

2007-09-01

High-throughput MS/MS was used to identify proteins secreted by Fusarium graminearum (Gibberella zeae) during growth on 13 media in vitro and in planta during infection of wheat heads. In vitro secreted proteins were collected from the culture filtrates, and in planta proteins were collected by vacuum infiltration. A total of 289 proteins (229 in vitro and 120 in planta) were identified with high statistical confidence. Forty-nine of the in planta proteins were not found in any of the in vitro conditions. The majority (91-100%) of the in vitro proteins had predicted signal peptides, but only 56% of the in planta proteins. At least 13 of the nonsecreted proteins found only in planta were single-copy housekeeping enzymes, including enolase, triose phosphate isomerase, phosphoglucomutase, calmodulin, aconitase, and malate dehydrogenase. The presence of these proteins in the in planta but not in vitro secretome might indicate that significant fungal lysis occurs during pathogenesis. On the other hand, several of the proteins lacking signal peptides that were found in planta have been reported to be potent immunogens secreted by animal pathogenic fungi, and therefore could be important in the interaction between F. graminearum and its host plants.

High production of D-tagatose, a potential sugar substitute, using immobilized L-arabinose isomerase.

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Kim, P; Yoon, S H; Roh, H J; Choi, J H

2001-01-01

An L-arabinose isomerase of Escherichia coli was immobilized using covalent binding to agarose to produce D-tagatose, a bulking sweetener that can be economically used as a sugar substitute. The immobilized L-arabinose isomerase stably produced an average of 7.5 g-tagatose/L.day for 7 days with a productivity exceeding that of the free enzyme (0.47 vs 0.30 mg/U.day). Using a scaled-up immobilized enzyme system, 99.9 g-tagatose/L was produced from galactose with 20% equilibrium in 48 h. The process was repeated two more times with production of 104.1 and 103.5 g-tagatose/L. D-Tagatose production using an immobilized L-arabinose isomerase has a high potential for commercial application.

Bacterial L-arabinose isomerases: industrial application for D-tagatose production.

Science.gov (United States)

Boudebbouze, Samira; Maguin, Emmanuelle; Rhimi, Moez

2011-12-01

D-tagatose is a natural monosaccharide with a low caloric value and has an anti-hyperglycemiant effect. This hexose has potential applications both in pharmaceutical and agro-food industries. However, the use of D-tagatose remains limited by its production cost. Many production procedures including chemical and biological processes were developed and patented. The most profitable production way is based on the use of L-arabinose isomerase which allows the manufacture of D-tagatose with an attractive rate. Future developments are focused on the generation of L-arabinose isomerases having biochemical properties satisfying the industrial applications. This report provides a brief review of the most recent patents that have been published relating to this area.

Directed evolution of xylose isomerase for improved xylose catabolism and fermentation in the yeast Saccharomyces cerevisiae.

Science.gov (United States)

Lee, Sun-Mi; Jellison, Taylor; Alper, Hal S

2012-08-01

The heterologous expression of a highly functional xylose isomerase pathway in Saccharomyces cerevisiae would have significant advantages for ethanol yield, since the pathway bypasses cofactor requirements found in the traditionally used oxidoreductase pathways. However, nearly all reported xylose isomerase-based pathways in S. cerevisiae suffer from poor ethanol productivity, low xylose consumption rates, and poor cell growth compared with an oxidoreductase pathway and, additionally, often require adaptive strain evolution. Here, we report on the directed evolution of the Piromyces sp. xylose isomerase (encoded by xylA) for use in yeast. After three rounds of mutagenesis and growth-based screening, we isolated a variant containing six mutations (E15D, E114G, E129D, T142S, A177T, and V433I) that exhibited a 77% increase in enzymatic activity. When expressed in a minimally engineered yeast host containing a gre3 knockout and tal1 and XKS1 overexpression, the strain expressing this mutant enzyme improved its aerobic growth rate by 61-fold and both ethanol production and xylose consumption rates by nearly 8-fold. Moreover, the mutant enzyme enabled ethanol production by these yeasts under oxygen-limited fermentation conditions, unlike the wild-type enzyme. Under microaerobic conditions, the ethanol production rates of the strain expressing the mutant xylose isomerase were considerably higher than previously reported values for yeast harboring a xylose isomerase pathway and were also comparable to those of the strains harboring an oxidoreductase pathway. Consequently, this study shows the potential to evolve a xylose isomerase pathway for more efficient xylose utilization.

Methods of measuring Protein Disulfide Isomerase activity: a critical overview

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Watanabe, Monica; Laurindo, Francisco; Fernandes, Denise

2014-09-01

Protein disulfide isomerase is an essential redox chaperone from the endoplasmic reticulum (ER) and is responsible for correct disulfide bond formation in nascent proteins. PDI is also found in other cellular locations in the cell, particularly the cell surface. Overall, PDI contributes to ER and global cell redox homeostasis and signaling. The knowledge about PDI structure and function progressed substantially based on in vitro studies using recombinant PDI and chimeric proteins. In these experimental scenarios, PDI reductase and chaperone activities are readily approachable. In contrast, assays to measure PDI isomerase activity, the hallmark of PDI family, are more complex. Assessment of PDI roles in cells and tissues mainly relies on gain- or loss-of-function studies. However, there is limited information regarding correlation of experimental readouts with the distinct types of PDI activities. In this mini-review, we evaluate the main methods described for measuring the different kinds of PDI activity: thiol reductase, thiol oxidase, thiol isomerase and chaperone. We emphasize the need to use appropriate controls and the role of critical interferents (e.g., detergent, presence of reducing agents). We also discuss the translation of results from in vitro studies with purified recombinant PDI to cellular and tissue samples, with critical comments on the interpretation of results.

Effect of pH on simultaneous saccharification and isomerization by glucoamylase and glucose isomerase.

Science.gov (United States)

Mishra, Abha; Debnath Das, Meera

2002-01-01

pH and temperature play critical roles in multistep enzymatic conversions. In such conversions, the optimal pH for individual steps differs greatly. In this article, we describe the production of glucoamylase (from Aspergillus oryzae MTCC152 in solid-state fermentation) and glucose isomerase (from Streptomyces griseus NCIM2020 in submerged fermentation), used in industries for producing high-fructose syrup. Optimum pH for glucoamylase was found to be 5.0. For glucose isomerase, the optimum pH ranged between 7.0 and 8.5, depending on the type of buffer used. Optimum temperature for glucoamylase and glucose isomerase was 50 and 60 degrees C, respectively. When both the enzymatic conversions were performed simultaneously at a compromised pH of 6.5, both the enzymes showed lowered activity. We also studied the kinetics at different pHs, which allows the two-step reaction to take place simultaneously. This was done by separating two steps by a thin layer of urease. Ammonia generated by the hydrolysis of urea consumed the hydrogen ions, thereby allowing optimal activity of glucose isomerase at an acidic pH of 5.0.

The secreted L-arabinose isomerase displays anti-hyperglycemic effects in mice.

Science.gov (United States)

Rhimi, Moez; Bermudez-Humaran, Luis G; Huang, Yuan; Boudebbouze, Samira; Gaci, Nadia; Garnier, Alexandrine; Gratadoux, Jean-Jacques; Mkaouar, Héla; Langella, Philippe; Maguin, Emmanuelle

2015-12-21

The L-arabinose isomerase is an intracellular enzyme which converts L-arabinose into L-ribulose in living systems and D-galactose into D-tagatose in industrial processes and at industrial scales. D-tagatose is a natural ketohexose with potential uses in pharmaceutical and food industries. The D-galactose isomerization reaction is thermodynamically equilibrated, and leads to secondary subproducts at high pH. Therefore, an attractive L-arabinose isomerase should be thermoactive and acidotolerant with high catalytic efficiency. While many reports focused on the set out of a low cost process for the industrial production of D-tagatose, these procedures remain costly. When compared to intracellular enzymes, the production of extracellular ones constitutes an interesting strategy to increase the suitability of the biocatalysts. The L-arabinose isomerase (L-AI) from Lactobacillus sakei was expressed in Lactococcus lactis in fusion with the signal peptide of usp45 (SP(Usp45)). The L-AI protein and activity were detected only in the supernatant of the induced cultures of the recombinant L. lactis demonstrating the secretion in the medium of the intracellular L. sakei L-AI in an active form. Moreover, we showed an improvement in the enzyme secretion using either (1) L. lactis strains deficient for their two major proteases, ClpP and HtrA, or (2) an enhancer of protein secretion in L. lactis fused to the recombinant L-AI with the SP(Usp45). Th L-AI enzyme secreted by the recombinant L. lactis strains or produced intracellularly in E. coli, showed the same functional properties than the native enzyme. Furthermore, when mice are fed with the L. lactis strain secreting the L-AI and galactose, tagatose was produced in vivo and reduced the glycemia index. We report for the first time the secretion of the intracellular L-arabinose isomerase in the supernatant of food grade L. lactis cultures with hardly display other secreted proteins. The secreted L-AI originated from the food

Structural and Biochemical Characterization of the Human Cyclophilin Family of Peptidyl-Prolyl Isomerases

Energy Technology Data Exchange (ETDEWEB)

Davis, Tara L.; Walker, John R.; Campagna-Slater, Valérie; Finerty, Jr., Patrick J.; Paramanathan, Ragika; Bernstein, Galina; MacKenzie, Farrell; Tempel, Wolfram; Ouyang, Hui; Lee, Wen Hwa; Eisenmesser, Elan Z.; Dhe-Paganon, Sirano (Toronto); (Colorado)

2011-12-14

Peptidyl-prolyl isomerases catalyze the conversion between cis and trans isomers of proline. The cyclophilin family of peptidyl-prolyl isomerases is well known for being the target of the immunosuppressive drug cyclosporin, used to combat organ transplant rejection. There is great interest in both the substrate specificity of these enzymes and the design of isoform-selective ligands for them. However, the dearth of available data for individual family members inhibits attempts to design drug specificity; additionally, in order to define physiological functions for the cyclophilins, definitive isoform characterization is required. In the current study, enzymatic activity was assayed for 15 of the 17 human cyclophilin isomerase domains, and binding to the cyclosporin scaffold was tested. In order to rationalize the observed isoform diversity, the high-resolution crystallographic structures of seven cyclophilin domains were determined. These models, combined with seven previously solved cyclophilin isoforms, provide the basis for a family-wide structure:function analysis. Detailed structural analysis of the human cyclophilin isomerase explains why cyclophilin activity against short peptides is correlated with an ability to ligate cyclosporin and why certain isoforms are not competent for either activity. In addition, we find that regions of the isomerase domain outside the proline-binding surface impart isoform specificity for both in vivo substrates and drug design. We hypothesize that there is a well-defined molecular surface corresponding to the substrate-binding S2 position that is a site of diversity in the cyclophilin family. Computational simulations of substrate binding in this region support our observations. Our data indicate that unique isoform determinants exist that may be exploited for development of selective ligands and suggest that the currently available small-molecule and peptide-based ligands for this class of enzyme are insufficient for isoform

Role of Loop-Clamping Side Chains in Catalysis by Triosephosphate Isomerase.

Science.gov (United States)

Zhai, Xiang; Amyes, Tina L; Richard, John P

2015-12-09

The side chains of Y208 and S211 from loop 7 of triosephosphate isomerase (TIM) form hydrogen bonds to backbone amides and carbonyls from loop 6 to stabilize the caged enzyme-substrate complex. The effect of seven mutations [Y208T, Y208S, Y208A, Y208F, S211G, S211A, Y208T/S211G] on the kinetic parameters for TIM catalyzed reactions of the whole substrates dihydroxyacetone phosphate and d-glyceraldehyde 3-phosphate [(k(cat)/K(m))(GAP) and (k(cat)/K(m))DHAP] and of the substrate pieces glycolaldehyde and phosphite dianion (k(cat)/K(HPi)K(GA)) are reported. The linear logarithmic correlation between these kinetic parameters, with slope of 1.04 ± 0.03, shows that most mutations of TIM result in an identical change in the activation barriers for the catalyzed reactions of whole substrate and substrate pieces, so that the transition states for these reactions are stabilized by similar interactions with the protein catalyst. The second linear logarithmic correlation [slope = 0.53 ± 0.16] between k(cat) for isomerization of GAP and K(d)(⧧) for phosphite dianion binding to the transition state for wildtype and many mutant TIM-catalyzed reactions of substrate pieces shows that ca. 50% of the wildtype TIM dianion binding energy, eliminated by these mutations, is expressed at the wildtype Michaelis complex, and ca. 50% is only expressed at the wildtype transition state. Negative deviations from this correlation are observed when the mutation results in a decrease in enzyme reactivity at the catalytic site. The main effect of Y208T, Y208S, and Y208A mutations is to cause a reduction in the total intrinsic dianion binding energy, but the effect of Y208F extends to the catalytic site.

Characteristics of chalcone isomerase promoter in crabapple leaves ...

African Journals Online (AJOL)

Anthocyanins are secondary metabolites found in higher plants that contribute to the colors of plants and chalcone isomerase (CHI) is one of the key enzymes in anthocyanin biosynthetic pathway. What characteristic is CHI promoter known as the regulation sequence of CHI gene, has been rarely investigated. We isolated A ...

Interaction of p53 with prolyl isomerases: Healthy and unhealthy relationships.

Science.gov (United States)

Mantovani, Fiamma; Zannini, Alessandro; Rustighi, Alessandra; Del Sal, Giannino

2015-10-01

The p53 protein family, comprising p53, p63 and p73, is primarily involved in preserving genome integrity and preventing tumor onset, and also affects a range of physiological processes. Signal-dependent modifications of its members and of other pathway components provide cells with a sophisticated code to transduce a variety of stress signaling into appropriate responses. TP53 mutations are highly frequent in cancer and lead to the expression of mutant p53 proteins that are endowed with oncogenic activities and sensitive to stress signaling. p53 family proteins have unique structural and functional plasticity, and here we discuss the relevance of prolyl-isomerization to actively shape these features. The anti-proliferative functions of the p53 family are carefully activated upon severe stress and this involves the interaction with prolyl-isomerases. In particular, stress-induced stabilization of p53, activation of its transcriptional control over arrest- and cell death-related target genes and of its mitochondrial apoptotic function, as well as certain p63 and p73 functions, all require phosphorylation of specific S/T-P motifs and their subsequent isomerization by the prolyl-isomerase Pin1. While these functions of p53 counteract tumorigenesis, under some circumstances their activation by prolyl-isomerases may have negative repercussions (e.g. tissue damage induced by anticancer therapies and ischemia-reperfusion, neurodegeneration). Moreover, elevated Pin1 levels in tumor cells may transduce deregulated phosphorylation signaling into activation of mutant p53 oncogenic functions. The complex repertoire of biological outcomes induced by p53 finds mechanistic explanations, at least in part, in the association between prolyl-isomerases and the p53 pathway. This article is part of a Special Issue entitled Proline-directed foldases: Cell signaling catalysts and drug targets. Copyright © 2015 Elsevier B.V. All rights reserved.

Kinase-dead ATM protein is highly oncogenic and can be preferentially targeted by Topo-isomerase I inhibitors.

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Yamamoto, Kenta; Wang, Jiguang; Sprinzen, Lisa; Xu, Jun; Haddock, Christopher J; Li, Chen; Lee, Brian J; Loredan, Denis G; Jiang, Wenxia; Vindigni, Alessandro; Wang, Dong; Rabadan, Raul; Zha, Shan

2016-06-15

Missense mutations in ATM kinase, a master regulator of DNA damage responses, are found in many cancers, but their impact on ATM function and implications for cancer therapy are largely unknown. Here we report that 72% of cancer-associated ATM mutations are missense mutations that are enriched around the kinase domain. Expression of kinase-dead ATM (Atm(KD/-)) is more oncogenic than loss of ATM (Atm(-/-)) in mouse models, leading to earlier and more frequent lymphomas with Pten deletions. Kinase-dead ATM protein (Atm-KD), but not loss of ATM (Atm-null), prevents replication-dependent removal of Topo-isomerase I-DNA adducts at the step of strand cleavage, leading to severe genomic instability and hypersensitivity to Topo-isomerase I inhibitors. Correspondingly, Topo-isomerase I inhibitors effectively and preferentially eliminate Atm(KD/-), but not Atm-proficientor Atm(-/-) leukemia in animal models. These findings identify ATM kinase-domain missense mutations as a potent oncogenic event and a biomarker for Topo-isomerase I inhibitor based therapy.

Cloning and characterization of peptidylprolyl isomerase B in the ...

African Journals Online (AJOL)

Peptidylprolyl isomerases (PPIases) play essential roles in protein folding and are implicated in immune response and cell cycle control. Our previous proteomic analysis indicated that Bombyx mori PPIases may be involved in anti- Bombyx mori nucleopolyhedrovirus (BmNPV) response. To help investigate this mechanism, ...

MTH1745, a protein disulfide isomerase-like protein from thermophilic archaea, Methanothermobacter thermoautotrophicum involving in stress response.

Science.gov (United States)

Ding, Xia; Lv, Zhen-Mei; Zhao, Yang; Min, Hang; Yang, Wei-Jun

2008-01-01

MTH1745 is a putative protein disulfide isomerase characterized with 151 amino acid residues and a CPAC active-site from the anaerobic archaea Methanothermobacter thermoautotrophicum. The potential functions of MTH1745 are not clear. In the present study, we show a crucial role of MTH1745 in protecting cells against stress which may be related to its functions as a disulfide isomerase and its chaperone properties. Using real-time polymerase chain reaction analyses, the level of MTH1745 messenger RNA (mRNA) in the thermophilic archaea M. thermoautotrophicum was found to be stress-induced in that it was significantly higher under low (50 degrees C) and high (70 degrees C) growth temperatures than under the optimal growth temperature for the organism (65 degrees C). Additionally, the expression of MTH1745 mRNA was up-regulated by cold shock (4 degrees C). Furthermore, the survival of MTH1745 expressing Escherichia coli cells was markedly higher than that of control cells in response to heat shock (51.0 degrees C). These results indicated that MTH1745 plays an important role in the resistance of stress. By assay of enzyme activities in vitro, MTH1745 also exhibited a chaperone function by promoting the functional folding of citrate synthase after thermodenaturation. On the other hand, MTH1745 was also shown to function as a disulfide isomerase on the refolding of denatured and reduced ribonuclease A. On the basis of its single thioredoxin domain, function as a disulfide isomerase, and its chaperone activity, we suggest that MTH1745 may be an ancient protein disulfide isomerase. These studies may provide clues to the understanding of the function of protein disulfide isomerase in archaea.

Biosynthesis of rare ketoses through constructing a recombination pathway in an engineered Corynebacterium glutamicum.

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Yang, Jiangang; Zhu, Yueming; Li, Jitao; Men, Yan; Sun, Yuanxia; Ma, Yanhe

2015-01-01

Rare sugars have various known biological functions and potential for applications in pharmaceutical, cosmetics, and food industries. Here we designed and constructed a recombination pathway in Corynebacterium glutamicum, in which dihydroxyacetone phosphate (DHAP), an intermediate of the glycolytic pathway, and a variety of aldehydes were condensed to synthesize rare ketoses sequentially by rhamnulose-1-phosphate aldolase (RhaD) and fructose-1-phosphatase (YqaB) obtained from Escherichia coli. A wild-type strain harboring this artificial pathway had the ability to produce D-sorbose and D-psicose using D-glyceraldehyde and glucose as the substrates. The tpi gene, encoding triose phosphate isomerase was further deleted, and the concentration of DHAP increased to nearly 20-fold relative to that of the wild-type. After additional optimization of expression levels from rhaD and yqaB genes and of the fermentation conditions, the engineered strain SY6(pVRTY) exhibited preferable performance for rare ketoses production. Its yield increased to 0.59 mol/mol D-glyceraldehyde from 0.33 mol/mol D-glyceraldehyde and productivity to 2.35 g/L h from 0.58 g/L h. Moreover, this strain accumulated 19.5 g/L of D-sorbose and 13.4 g/L of D-psicose using a fed-batch culture mode under the optimal conditions. In addition, it was verified that the strain SY6(pVRTY) meanwhile had the ability to synthesize C4, C5, C6, and C7 rare ketoses when a range of representative achiral and homochiral aldehydes were applied as the substrates. Therefore, the platform strain exhibited the potential for microbial production of rare ketoses and deoxysugars. © 2014 Wiley Periodicals, Inc.

Light dependence of carboxylation capacity for C3 photosynthesis models

Science.gov (United States)

Photosynthesis at high light is often modelled by assuming limitation by the maximum capacity of Rubisco carboxylation at low carbon dioxide concentrations, by electron transport capacity at higher concentrations, and sometimes by triose-phosphate utilization rate at the highest concentrations. Pho...

Obtaining mutants of Streptomyces griseoflavus strain 1339, producers of glucose isomerase, following gamma irradiation

International Nuclear Information System (INIS)

Dzhedzheva, G.; Stoeva, N.; Stojchev, M.

1990-01-01

A water suspension of Streptomyces griseoflavus strain 1339 spores of a density of 8.7.10 6 spores/cm 3 is gamma irradiated ( 60 Co, RHM-γ-20, 30.3 Gy/min). The survival of Streptomyces griseoflavus strain 1339 spores was determined depending on radiation doses, exposure times and incubation temperature. Five major morphological types of colonies were isolated, characterized by different levels of glucose isomerase activity. Maximum specific glucose isomerase activity (GIU/g) was attained after the third gamma irradiation step using a dose of 3000 Gy. 2 tabs., 3 figs., 7 refs

Structural and thermodynamic insights into chitooligosaccharide binding to human cartilage chitinase 3-like protein 2 (CHI3L2 or YKL-39).

Science.gov (United States)

Ranok, Araya; Wongsantichon, Jantana; Robinson, Robert C; Suginta, Wipa

2015-01-30

Four crystal structures of human YKL-39 were solved in the absence and presence of chitooligosaccharides. The structure of YKL-39 comprises a major (β/α)8 triose-phosphate isomerase barrel domain and a small α + β insertion domain. Structural analysis demonstrates that YKL-39 interacts with chitooligosaccharides through hydrogen bonds and hydrophobic interactions. The binding of chitin fragments induces local conformational changes that facilitate tight binding. Compared with other GH-18 members, YKL-39 has the least extended chitin-binding cleft, containing five subsites for sugars, namely (-3)(-2)(-1)(+1)(+2), with Trp-360 playing a prominent role in the sugar-protein interactions at the center of the chitin-binding cleft. Evaluation of binding affinities obtained from isothermal titration calorimetry and intrinsic fluorescence spectroscopy suggests that YKL-39 binds to chitooligosaccharides with Kd values in the micromolar concentration range and that the binding energies increase with the chain length. There were no significant differences between the Kd values of chitopentaose and chitohexaose, supporting the structural evidence for the five binding subsite topology. Thermodynamic analysis indicates that binding of chitooligosaccharide to YKL-39 is mainly driven by enthalpy. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

L'endométriose périnéale profonde sur cicatrice d’épisiotomie: à propos d'un cas rare

OpenAIRE

Laadioui, Meriem; Alaoui, Fdili; Jayi, Sofia; Bouguern, Hakima; Chaara, Hikmat; Melhouf, Moulay Aabdelilah

2013-01-01

Parmi les localisations rares de l'endométriose sur cicatrice, celle du périnée demeure exceptionnelle, l'origine en est souvent iatrogène (épisiotomie). Nous rapportons le cas d'une patiente présentant une douleur cyclique, au niveau de la cicatrice d’épisiotomie. Avec à l'examen clinique une masse de 3,5 cm de grand diamètre au niveau de la cicatrice d’épisiotomie. L’écho périnéale a objectivé une image hypoéchgène hétérogène non vascularisée en regard de la cicatrice d’épisiotomie faisant ...

D-Tagatose production in the presence of borate by resting Lactococcus lactis cells harboring Bifidobacterium longum L-arabinose isomerase.

Science.gov (United States)

Salonen, Noora; Salonen, Kalle; Leisola, Matti; Nyyssölä, Antti

2013-04-01

Bifidobacterium longum NRRL B-41409 L-arabinose isomerase (L-AI) was overexpressed in Lactococcus lactis using a phosphate depletion inducible expression system. The resting L. lactis cells harboring the B. longum L-AI were used for production of D-tagatose from D-galactose in the presence of borate buffer. Multivariable analysis suggested that high pH, temperature and borate concentration favoured the conversion of D-galactose to D-tagatose. Almost quantitative conversion (92 %) was achieved at 20 g L⁻¹ substrate and at 37.5 °C after 5 days. The D-tagatose production rate of 185 g L⁻¹ day ⁻¹ was obtained at 300 g L⁻¹ galactose, at 1.15 M borate, and at 41 °C during 10 days when the production medium was changed every 24 h. There was no significant loss in productivity during ten sequential 24 h batches. The initial D-tagatose production rate was 290 g L⁻¹ day⁻¹ under these conditions.

Genomic analysis of a xylose operon and characterization of novel xylose isomerase and xylulokinase from Bacillus coagulans NL01.

Science.gov (United States)

Zheng, Zhaojuan; Lin, Xi; Jiang, Ting; Ye, Weihua; Ouyang, Jia

2016-08-01

To investigate the xylose operon and properties of xylose isomerase and xylulokinase in Bacillus coagulans that can effectively ferment xylose to lactic acid. The xylose operon is widely present in B. coagulans. It is composed of four putative ORFs. Novel xylA and xylB from B. coagulans NL01 were cloned and expressed in Escherichia coli. Sequence of xylose isomerase was more conserved than that of xylulokinase. Both the enzymes exhibited maximum activities at pH 7-8 but with a high temperature maximum of 80-85 °C, divalent metal ion was prerequisite for their activation. Xylose isomerase and xylulokinase were most effectively activated by Ni(2+) and Co(2+), respectively. Genomic analysis of xylose operon has contributed to understanding xylose metabolism in B. coagulans and the novel xylose isomerase and xylulokinase might provide new alternatives for metabolic engineering of other strains to improve their fermentation performance on xylose.

The drug ornidazole inhibits photosynthesis in a different mechanism described for protozoa and anaerobic bacteria.

Science.gov (United States)

Marcus, Yehouda; Tal, Noam; Ronen, Mordechai; Carmieli, Raanan; Gurevitz, Michael

2016-12-01

Ornidazole of the 5-nitroimidazole drug family is used to treat protozoan and anaerobic bacterial infections via a mechanism that involves preactivation by reduction of the nitro group, and production of toxic derivatives and radicals. Metronidazole, another drug family member, has been suggested to affect photosynthesis by draining electrons from the electron carrier ferredoxin, thus inhibiting NADP + reduction and stimulating radical and peroxide production. Here we show, however, that ornidazole inhibits photosynthesis via a different mechanism. While having a minute effect on the photosynthetic electron transport and oxygen photoreduction, ornidazole hinders the activity of two Calvin cycle enzymes, triose-phosphate isomerase (TPI) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Modeling of ornidazole's interaction with ferredoxin of the protozoan Trichomonas suggests efficient electron tunneling from the iron-sulfur cluster to the nitro group of the drug. A similar docking site of ornidazole at the plant-type ferredoxin does not exist, and the best simulated alternative does not support such efficient tunneling. Notably, TPI was inhibited by ornidazole in the dark or when electron transport was blocked by dichloromethyl diphenylurea, indicating that this inhibition was unrelated to the electron transport machinery. Although TPI and GAPDH isoenzymes are involved in glycolysis and gluconeogenesis, ornidazole's effect on respiration of photoautotrophs is moderate, thus raising its value as an efficient inhibitor of photosynthesis. The scarcity of Calvin cycle inhibitors capable of penetrating cell membranes emphasizes on the value of ornidazole for studying the regulation of this cycle. © 2016 The Author(s); published by Portland Press Limited on behalf of the Biochemical Society.

[Deficiency of triosephosphate isomerase. Apropos of 2 new cases].

Science.gov (United States)

Delso Martínez, M C; Uriel Miñana, P; Pérez Lugmus, G; Giménez Mas, J A; Baldellou Vázquez, A

1983-08-01

Two siblings, born of a no consanguineous couple, a female and a male, affected by a severe and progressive neurological disease and chronic hemolytic anemia are presented. Their clinical, hematological, biochemical and pathological studies are discussed. One of the patients showed a triosephosphate isomerase deficiency and the carrier condition of their parents was tested. Commentaries about physiopathology of this disease are made.

Demonstration of glycosomes (microbodies) in the Bodonid flagellate Trypanoplasma borelli (Protozoa, Kinetoplastida)

NARCIS (Netherlands)

Opperdoes, Fred R.; Nohynkova, Eva; Schaftingen, Emile Van; Lambeir, Anne-Marie; Veenhuis, Marten; Roy, Joris Van

1988-01-01

Homogenates of Trypanoplasma borelli were subjected to subcellular fractionation by sequential differential and isopycnic centrifugation in sucrose. Glycerol-3-phosphate dehydrogenase and the glycolytic enzymes, glucosephosphate isomerase and triosephosphate isomerase, as well as the peroxisomal

Physiological and Pathogenic Roles of Prolyl Isomerase Pin1 in Metabolic Regulations via Multiple Signal Transduction Pathway Modulations

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Yusuke Nakatsu

2016-09-01

Full Text Available Prolyl isomerases are divided into three groups, the FKBP family, Cyclophilin and the Parvulin family (Pin1 and Par14. Among these isomerases, Pin1 is a unique prolyl isomerase binding to the motif including pSer/pThr-Pro that is phosphorylated by kinases. Once bound, Pin1 modulates the enzymatic activity, protein stability or subcellular localization of target proteins by changing the cis- and trans-formations of proline. Several studies have examined the roles of Pin1 in the pathogenesis of cancers and Alzheimer’s disease. On the other hand, recent studies have newly demonstrated Pin1 to be involved in regulating glucose and lipid metabolism. Interestingly, while Pin1 expression is markedly increased by high-fat diet feeding, Pin1 KO mice are resistant to diet-induced obesity, non-alcoholic steatohepatitis and diabetic vascular dysfunction. These phenomena result from the binding of Pin1 to several key factors regulating metabolic functions, which include insulin receptor substrate-1, AMPK, Crtc2 and NF-κB p65. In this review, we focus on recent advances in elucidating the physiological roles of Pin1 as well as the pathogenesis of disorders involving this isomerase, from the viewpoint of the relationships between signal transductions and metabolic functions.

SAXS-WAXS studies of the low-resolution structure in solution of xylose/glucose isomerase from Streptomyces rubiginosus

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Kozak, Maciej; Taube, Michał

2009-10-01

The structure and conformation of molecule of xylose/glucose isomerase from Streptomyces rubiginosus in solution (at pH 6 and 7.6; with and without the substrate) has been studied by small- and wide-angle scattering of synchrotron radiation (SAXS-WAXS). On the basis of the SAXS-WAXS data, the low-resolution structure in solution has been reconstructed using ab inito methods. A comparison of the models of glucose isomerase shows only small differences between the model in solution and the crystal structure.

A zebrafish model of congenital disorders of glycosylation with phosphomannose isomerase deficiency reveals an early opportunity for corrective mannose supplementation

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Jaime Chu

2013-01-01

Individuals with congenital disorders of glycosylation (CDG have recessive mutations in genes required for protein N-glycosylation, resulting in multi-systemic disease. Despite the well-characterized biochemical consequences in these individuals, the underlying cellular defects that contribute to CDG are not well understood. Synthesis of the lipid-linked oligosaccharide (LLO, which serves as the sugar donor for the N-glycosylation of secretory proteins, requires conversion of fructose-6-phosphate to mannose-6-phosphate via the phosphomannose isomerase (MPI enzyme. Individuals who are deficient in MPI present with bleeding, diarrhea, edema, gastrointestinal bleeding and liver fibrosis. MPI-CDG patients can be treated with oral mannose supplements, which is converted to mannose-6-phosphate through a minor complementary metabolic pathway, restoring protein glycosylation and ameliorating most symptoms, although liver disease continues to progress. Because Mpi deletion in mice causes early embryonic lethality and thus is difficult to study, we used zebrafish to establish a model of MPI-CDG. We used a morpholino to block mpi mRNA translation and established a concentration that consistently yielded 13% residual Mpi enzyme activity at 4 days post-fertilization (dpf, which is within the range of MPI activity detected in fibroblasts from MPI-CDG patients. Fluorophore-assisted carbohydrate electrophoresis detected decreased LLO and N-glycans in mpi morphants. These deficiencies resulted in 50% embryonic lethality by 4 dpf. Multi-systemic abnormalities, including small eyes, dysmorphic jaws, pericardial edema, a small liver and curled tails, occurred in 82% of the surviving larvae. Importantly, these phenotypes could be rescued with mannose supplementation. Thus, parallel processes in fish and humans contribute to the phenotypes caused by Mpi depletion. Interestingly, mannose was only effective if provided prior to 24 hpf. These data provide insight into treatment efficacy

Studies on the production of glucose isomerase by Bacillus licheniformis

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Nwokoro Ogbonnaya

2015-09-01

Full Text Available This work reports the effects of some culture conditions on the production of glucose isomerase by Bacillus licheniformis. The bacterium was selected based on the release of 3.62 mg/mL fructose from the fermentation of glucose. Enzyme was produced using a variety of carbon substrates but the highest enzyme activity was detected in a medium containing 0.5% xylose and 1% glycerol (specific activity = 6.88 U/mg protein. Media containing only xylose or glucose gave lower enzyme productivies (specific activities= 4.60 and 2.35 U/mg protein respectively. The effects of nitrogen substrates on glucose isomerase production showed that yeast extract supported maximum enzyme activity (specific activity = 5.24 U/mg protein. Lowest enzyme activity was observed with sodium trioxonitrate (specific activity = 2.44 U/mg protein. In general, organic nitrogen substrates supported higher enzyme productivity than inorganic nitrogen substrates. Best enzyme activity was observed in the presence of Mg2+ (specific activity = 6.85 U/mg protein while Hg2+ was inhibitory (specific activity = 1.02 U/mg protein. The optimum pH for best enzyme activity was 6.0 while optimum temperature for enzyme production was 50ºC.

Glucose(xylose isomerase production by Streptomyces sp. CH7 grown on agricultural residues

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Kankiya Chanitnun

2012-09-01

Full Text Available Streptomyces sp. CH7 was found to efficiently produce glucose(xylose isomerase when grown on either xylan or agricultural residues. This strain produced a glucose(xylose isomerase activity of roughly 1.8 U/mg of protein when it was grown in medium containing 1% xylose as a carbon source. Maximal enzymatic activities of about 5 and 3 U/mg were obtained when 1% xylan and 2.5% corn husks were used, respectively. The enzyme was purified from a mycelial extract to 16-fold purity with only two consecutive column chromatography steps using Macro-prep DEAE and Sephacryl-300, respectively. The approximate molecular weight of the purified enzyme is 170 kDa, and it has four identical subunits of 43.6 kDa as estimated by SDS-PAGE. Its Km values for glucose and xylose were found to be 258.96 and 82.77 mM, respectively, and its Vmax values are 32.42 and 63.64 μM/min/mg, respectively. The purified enzyme is optimally active at 85ºC and pH 7.0. It is stable at pH 5.5-8.5 and at temperatures up to 60ºC after 30 min. These findings indicate that glucose(xylose isomerase from Streptomyces sp. CH7 has the potential for industrial applications, especially for high-fructose syrup production and bioethanol fermentation from hemicellulosic hydrolysates by Saccharomyces cerevisiae.

Biomimicry enhances sequential reactions of tethered glycolytic enzymes, TPI and GAPDHS.

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Chinatsu Mukai

Full Text Available Maintaining activity of enzymes tethered to solid interfaces remains a major challenge in developing hybrid organic-inorganic devices. In nature, mammalian spermatozoa have overcome this design challenge by having glycolytic enzymes with specialized targeting domains that enable them to function while tethered to a cytoskeletal element. As a step toward designing a hybrid organic-inorganic ATP-generating system, we implemented a biomimetic site-specific immobilization strategy to tether two glycolytic enzymes representing different functional enzyme families: triose phosphoisomerase (TPI; an isomerase and glyceraldehyde 3-phosphate dehydrogenase (GAPDHS; an oxidoreductase. We then evaluated the activities of these enzymes in comparison to when they were tethered via classical carboxyl-amine crosslinking. Both enzymes show similar surface binding regardless of immobilization method. Remarkably, specific activities for both enzymes were significantly higher when tethered using the biomimetic, site-specific immobilization approach. Using this biomimetic approach, we tethered both enzymes to a single surface and demonstrated their function in series in both forward and reverse directions. Again, the activities in series were significantly higher in both directions when the enzymes were coupled using this biomimetic approach versus carboxyl-amine binding. Our results suggest that biomimetic, site-specific immobilization can provide important functional advantages over chemically specific, but non-oriented attachment, an important strategic insight given the growing interest in recapitulating entire biological pathways on hybrid organic-inorganic devices.

Biomimicry enhances sequential reactions of tethered glycolytic enzymes, TPI and GAPDHS.

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Mukai, Chinatsu; Gao, Lizeng; Bergkvist, Magnus; Nelson, Jacquelyn L; Hinchman, Meleana M; Travis, Alexander J

2013-01-01

Maintaining activity of enzymes tethered to solid interfaces remains a major challenge in developing hybrid organic-inorganic devices. In nature, mammalian spermatozoa have overcome this design challenge by having glycolytic enzymes with specialized targeting domains that enable them to function while tethered to a cytoskeletal element. As a step toward designing a hybrid organic-inorganic ATP-generating system, we implemented a biomimetic site-specific immobilization strategy to tether two glycolytic enzymes representing different functional enzyme families: triose phosphoisomerase (TPI; an isomerase) and glyceraldehyde 3-phosphate dehydrogenase (GAPDHS; an oxidoreductase). We then evaluated the activities of these enzymes in comparison to when they were tethered via classical carboxyl-amine crosslinking. Both enzymes show similar surface binding regardless of immobilization method. Remarkably, specific activities for both enzymes were significantly higher when tethered using the biomimetic, site-specific immobilization approach. Using this biomimetic approach, we tethered both enzymes to a single surface and demonstrated their function in series in both forward and reverse directions. Again, the activities in series were significantly higher in both directions when the enzymes were coupled using this biomimetic approach versus carboxyl-amine binding. Our results suggest that biomimetic, site-specific immobilization can provide important functional advantages over chemically specific, but non-oriented attachment, an important strategic insight given the growing interest in recapitulating entire biological pathways on hybrid organic-inorganic devices.

Prevalence of Selected Zoonotic and Vector-Borne Agents in Dogs and Cats on the Pine Ridge Reservation

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A. Valeria Scorza

2017-09-01

Full Text Available The prevalence of intestinal parasites and vector-borne agents of dogs and cats in the Pine Ridge Reservation, South Dakota were determined. Fecal samples (84 dogs, 9 cats were examined by centrifugal floatation and by immunofluorescence assay (FA for Giardia and Cryptosporidium. PCR was performed on Giardia [beta-giardin (bg, triose phosphate isomerase (tpi, glutamate dehydrogenase genes (gdh] and Cryptosporidium [heat shock protein-70 gene (hsp] FA positive samples. Cat sera (n = 32 were tested for antibodies against Bartonella spp., Toxoplasma gondii, and FIV, and antigens of FeLV and Dirofilaria immitis. Dog sera (n = 82 were tested for antibodies against T. gondii, Borrelia burgdorferi, Ehrlichia canis, and Anaplasma phagocytophilum and D. immitis antigen. Blood samples (92 dogs, 39 cats were assessed by PCR for amplification of DNA of Bartonella spp., Ehrlichia spp., Anaplasma spp., haemoplasmas, and Babesia spp. (dogs only. The most significant results were Giardia spp. (32% by FA, Taenia spp. (17.8% and Cryptosporidium spp. (7.1%. The Giardia isolates typed as the dog-specific assemblages C or D and four Cryptosporidium isolates typed as C. canis. Antibodies against T. gondii were detected in 15% of the dogs. Antibodies against Bartonella spp. and against T. gondii were detected in 37.5% and 6% of the cats respectively. FeLV antigen was detected in 10% of the cats.

Multilocus genotyping of Giardia duodenalis in captive non-human primates in Sichuan and Guizhou provinces, Southwestern China.

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Zhijun Zhong

Full Text Available Giardia duodenalis is a common human and animal pathogen. It has been increasingly reported in wild and captive non-human primates (NHPs in recent years. However, multilocus genotyping information for G. duodenalis infecting NHPs in southwestern China is limited. In the present study, the prevalence and multilocus genotypes (MLGs of G. duodenalis in captive NHPs in southwestern China were determined. We examined 207 fecal samples from NHPs in Sichuan and Guizhou provinces, and 16 specimens were positive for G. duodenalis. The overall infection rate was 7.7%, and only assemblage B was identified. G. duodenalis was detect positive in northern white-cheeked gibbon (14/36, 38.9%, crab-eating macaque (1/60, 1.7% and rhesus macaques (1/101, 0.9%. Multilocus sequence typing based on beta-giardin (bg, triose phosphate isomerase (tpi and glutamate dehydrogenase (gdh revealed nine different assemblage B MLGs (five known genotypes and four novel genotypes. Based on a phylogenetic analysis, one potentially zoonotic genotype of MLG SW7 was identified in a northern white-cheeked gibbon. A high degree of genetic diversity within assemblage B was observed in captive northern white-cheeked gibbons in Southwestern China, including a potentially zoonotic genotype, MLG SW7. To the best of our knowledge, this is the first report using a MLGs approach to identify G. duodenalis in captive NHPs in Southwestern China.

Prevalence of Clostridium difficile toxinotypes in infected patients at a tertiary care center in Lebanon.

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Moukhaiber, Romy; Araj, George F; Kissoyan, Kohar Annie B; Cheaito, Katia A; Matar, Ghassan M

2015-07-30

Due to the increase in the incidence of Clostridium difficile associated diseases at a tertiary care center in Lebanon, this study was undertaken to determine the prevalent C. difficile toxinotypes. The immunocard method was used to test for toxins A and B in 88 collected stool samples, followed with API 20A to confirm for C. difficile. PCR amplification of the triose phosphate isomerase (tpi) gene, the toxin encoding genes tcdA, and tcdB, followed by toxinotyping, were performed on recovered isolates and stool specimens. Out of the 88 stool samples obtained, 30 (65.2%) were Immunocard positive, culture and or tpi positive for C. difficile. Of the 30 isolates, 4 were PCR negative for the tcdA and tcdB genes (A-B-), and 26 were PCR positive for the tcdA and / or tcdB genes with 4 being A+B+, 1 A+B-, and 21 A-B+. The results of toxinotyping showed that 2 isolates belonged to toxinotype 0, 4 to toxinotype XI, 2 to toxinotype XII, 1 to toxinotype XVI, 1(A+B-) and twenty (A-B+) designated as toxinotype 0-like. C. difficile was detected in 65.2% of patients' stools with prevalence of toxinotype 0-like. Identification of toxinotypes of C. difficile is important to determine the virulence potential of strains and control their spread.

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

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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.

Bioconversion of D-galactose into D-tagatose by expression of L-arabinose isomerase.

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Roh, H J; Kim, P; Park, Y C; Choi, J H

2000-02-01

D-Tagatose is a potential bulking agent in food as a non-calorific sweetener. To produce D-tagatose from cheaper resources, plasmids harbouring the L-arabinose isomerase gene (araA) from Escherichia coli, Bacillus subtilis and Salmonella typhimurium were constructed because L-arabinose isomerase was suggested previously as an enzyme that mediates the bioconversion of galactose into tagatose as well as that of arabinose to ribulose. The constructed plasmids were named pTC101, pTC105 and pTC106, containing araA from E. coli, B. subtilis and S. typhimurium respectively. In the cultures of recombinant E. coli with pTC101, pTC105 and pTC106, tagatose was produced from galactose in 9.9, 7.1 and 6.9% yields respectively. The enzyme extract of E. coli with the plasmid pTC101 also converted galactose into tagatose with a 96.4% yield.

Open reading frame 176 in the photosynthesis gene cluster of Rhodobacter capsulatus encodes idi, a gene for isopentenyl diphosphate isomerase.

OpenAIRE

Hahn, F M; Baker, J A; Poulter, C D

1996-01-01

Isopentenyl diphosphate (IPP) isomerase catalyzes an essential activation step in the isoprenoid biosynthetic pathway. A database search based on probes from the highly conserved regions in three eukaryotic IPP isomerases revealed substantial similarity with ORF176 in the photosynthesis gene cluster in Rhodobacter capsulatus. The open reading frame was cloned into an Escherichia coli expression vector. The encoded 20-kDa protein, which was purified in two steps by ion exchange and hydrophobic...

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

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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.

Binding of 5-phospho-D-arabinonohydroxamate and 5-phospho-D-arabinonate inhibitors to zinc phosphomannose isomerase from Candida albicans studied by polarizable molecular mechanics and quantum mechanics.

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Roux, Celine; Gresh, Nohad; Perera, Lalith E; Piquemal, Jean-Philip; Salmon, Laurent

2007-04-15

Type I phosphomannose isomerase (PMI) is a Zn-dependent metalloenzyme involved in the isomerization of D-fructose 6-phosphate to D-mannose 6-phosphate. One of our laboratories has recently designed and synthesized 5-phospho-D-arabinonohydroxamate (5PAH), an inhibitor endowed with a nanomolar affinity for PMI (Roux et al., Biochemistry 2004, 43, 2926). By contrast, the 5-phospho-D-arabinonate (5PAA), in which the hydroxamate moiety is replaced by a carboxylate one, is devoid of inhibitory potency. Subsequent biochemical studies showed that in its PMI complex, 5PAH binds Zn(II) through its hydroxamate moiety rather than through its phosphate. These results have stimulated the present theoretical investigation in which we resort to the SIBFA polarizable molecular mechanics procedure to unravel the structural and energetical aspects of 5PAH and 5PAA binding to a 164-residue model of PMI. Consistent with the experimental results, our theoretical studies indicate that the complexation of PMI by 5PAH is much more favorable than by 5PAA, and that in the 5PAH complex, Zn(II) ligation by hydroxamate is much more favorable than by phosphate. Validations by parallel quantum-chemical computations on model of the recognition site extracted from the PMI-inhibitor complexes, and totaling up to 140 atoms, showed the values of the SIBFA intermolecular interaction energies in such models to be able to reproduce the quantum-chemistry ones with relative errors < 3%. On the basis of the PMI-5PAH SIBFA energy-minimized structure, we report the first hypothesis of a detailed view of the active site of the zinc PMI complexed to the high-energy intermediate analogue inhibitor, which allows us to identify active site residues likely involved in the proton transfer between the two adjacent carbons of the substrates. (c) 2007 Wiley Periodicals, Inc.

Enzymatic conversion of D-galactose to D-tagatose: heterologous expression and characterisation of a thermostable L-arabinose isomerase from Thermoanaerobacter mathranii.

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Jørgensen, F; Hansen, O C; Stougaard, P

2004-06-01

The ability to convert D-galactose into D-tagatose was compared among a number of bacterial L-arabinose isomerases ( araA). One of the most efficient enzymes, from the anaerobic thermophilic bacterium Thermoanaerobacter mathranii, was produced heterologously in Escherichia coli and characterised. Amino acid sequence comparisons indicated that this enzyme is only distantly related to the group of previously known araA sequences in which the sequence similarity is evident. The substrate specificity and the Michaelis-Menten constants of the enzyme determined with L-arabinose, D-galactose and D-fucose also indicated that this enzyme is an unusual, versatile L-arabinose isomerase which is able to isomerise structurally related sugars. The enzyme was immobilised and used for production of D-tagatose at 65 degrees C. Starting from a 30% solution of D-galactose, the yield of D-tagatose was 42% and no sugars other than D-tagatose and D-galactose were detected. Direct conversion of lactose to D-tagatose in a single reactor was demonstrated using a thermostable beta-galactosidase together with the thermostable L-arabinose isomerase. The two enzymes were also successfully combined with a commercially available glucose isomerase for conversion of lactose into a sweetening mixture comprising lactose, glucose, galactose, fructose and tagatose.

A library of fluorescent peptides for exploring the substrate specificities of prolyl isomerases

NARCIS (Netherlands)

Zoldak, G.; Aumuller, T.; Lucke, C.; Hritz, J.; Oostenbrink, C.; Fischer, G.; Schmid, F.X.

2009-01-01

To fully explore the substrate specificities of prolyl isomerases, we synthesized a library of 20 tetrapeptides that are labeled with a 2-aminobenzoyl (Abz) group at the amino terminus and a p-nitroanilide (pNA) group at the carboxy terminus. In this peptide library of the general formula

Crystallization and preliminary X-ray diffraction studies of l-rhamnose isomerase from Pseudomonas stutzeri

International Nuclear Information System (INIS)

Yoshida, Hiromi; Wayoon, Poonperm; Takada, Goro; Izumori, Ken; Kamitori, Shigehiro

2006-01-01

Recombinant l-rhamnose isomerase from P. stutzeri has been crystallized. Diffraction data have been collected to 2.0 Å resolution. l-Rhamnose isomerase from Pseudomonas stutzeri (P. stutzeril-RhI) catalyzes not only the reversible isomerization of l-rhamnose to l-rhamnulose, but also isomerization between various rare aldoses and ketoses. Purified His-tagged P. stutzeril-RhI was crystallized by the hanging-drop vapour-diffusion method. The crystals belong to the monoclinic space group P2 1 , with unit-cell parameters a = 74.3, b = 104.0, c = 107.0 Å, β = 106.8°. Diffraction data have been collected to 2.0 Å resolution. The molecular weight of the purified P. stutzeril-RhI with a His tag at the C-terminus was confirmed to be 47.7 kDa by MALDI–TOF mass-spectrometric analysis and the asymmetric unit is expected to contain four molecules

Structural, kinetic and proteomic characterization of acetyl phosphate-dependent bacterial protein acetylation.

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Misty L Kuhn

Full Text Available The emerging view of Nε-lysine acetylation in eukaryotes is of a relatively abundant post-translational modification (PTM that has a major impact on the function, structure, stability and/or location of thousands of proteins involved in diverse cellular processes. This PTM is typically considered to arise by the donation of the acetyl group from acetyl-coenzyme A (acCoA to the ε-amino group of a lysine residue that is reversibly catalyzed by lysine acetyltransferases and deacetylases. Here, we provide genetic, mass spectrometric, biochemical and structural evidence that Nε-lysine acetylation is an equally abundant and important PTM in bacteria. Applying a recently developed, label-free and global mass spectrometric approach to an isogenic set of mutants, we detected acetylation of thousands of lysine residues on hundreds of Escherichia coli proteins that participate in diverse and often essential cellular processes, including translation, transcription and central metabolism. Many of these acetylations were regulated in an acetyl phosphate (acP-dependent manner, providing compelling evidence for a recently reported mechanism of bacterial Nε-lysine acetylation. These mass spectrometric data, coupled with observations made by crystallography, biochemistry, and additional mass spectrometry showed that this acP-dependent acetylation is both non-enzymatic and specific, with specificity determined by the accessibility, reactivity and three-dimensional microenvironment of the target lysine. Crystallographic evidence shows acP can bind to proteins in active sites and cofactor binding sites, but also potentially anywhere molecules with a phosphate moiety could bind. Finally, we provide evidence that acP-dependent acetylation can impact the function of critical enzymes, including glyceraldehyde-3-phosphate dehydrogenase, triosephosphate isomerase, and RNA polymerase.

Carbohydrate metabolism of Xylella fastidiosa: Detection of glycolytic and pentose phosphate pathway enzymes and cloning and expression of the enolase gene

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Facincani Agda Paula

2003-01-01

Full Text Available The objective of this work was to assess the functionality of the glycolytic pathways in the bacterium Xylella fastidiosa. To this effect, the enzymes phosphoglucose isomerase, aldolase, glyceraldehyde-3-phosphate dehydrogenase and pyruvate kinase of the glycolytic pathway, and glucose 6-phosphate dehydrogenase of the Entner-Doudoroff pathway were studied, followed by cloning and expression studies of the enolase gene and determination of its activity. These studies showed that X. fastidiosa does not use the glycolytic pathway to metabolize carbohydrates, which explains the increased duplication time of this phytopatogen. Recombinant enolase was expressed as inclusion bodies and solubilized with urea (most efficient extractor, Triton X-100, and TCA. Enolase extracted from X. fastidiosa and from chicken muscle and liver is irreversibly inactivated by urea. The purification of enolase was partial and resulted in a low yield. No enzymatic activity was detected for either recombinant and native enolases, aldolase, and glyceraldehyde-3-phosphate dehydrogenase, suggesting that X. fastidiosa uses the Entner-Doudoroff pathway to produce pyruvate. Evidence is presented supporting the idea that the regulation of genes and the presence of isoforms with regulation patterns might make it difficult to understand the metabolism of carbohydrates in X. fastidiosa.

Reconstruction of Oryza sativa indica Genome Scale Metabolic Model and Its Responses to Varying RuBisCO Activity, Light Intensity, and Enzymatic Cost Conditions

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Ankita Chatterjee

2017-11-01

Full Text Available To combat decrease in rice productivity under different stresses, an understanding of rice metabolism is needed. Though there are different genome scale metabolic models (GSMs of Oryza sativa japonica, no GSM with gene-protein-reaction association exist for Oryza sativa indica. Here, we report a GSM, OSI1136 of O.s. indica, which includes 3602 genes and 1136 metabolic reactions and transporters distributed across the cytosol, mitochondrion, peroxisome, and chloroplast compartments. Flux balance analysis of the model showed that for varying RuBisCO activity (Vc/Vo (i the activity of the chloroplastic malate valve increases to transport reducing equivalents out of the chloroplast under increased photorespiratory conditions and (ii glyceraldehyde-3-phosphate dehydrogenase and phosphoglycerate kinase can act as source of cytosolic ATP under decreased photorespiration. Under increasing light conditions we observed metabolic flexibility, involving photorespiration, chloroplastic triose phosphate and the dicarboxylate transporters of the chloroplast and mitochondrion for redox and ATP exchanges across the intracellular compartments. Simulations under different enzymatic cost conditions revealed (i participation of peroxisomal glutathione-ascorbate cycle in photorespiratory H2O2 metabolism (ii different modes of the chloroplastic triose phosphate transporters and malate valve, and (iii two possible modes of chloroplastic Glu–Gln transporter which were related with the activity of chloroplastic and cytosolic isoforms of glutamine synthetase. Altogether, our results provide new insights into plant metabolism.

The acid-tolerant L-arabinose isomerase from the mesophilic Shewanella sp. ANA-3 is highly active at low temperatures

Science.gov (United States)

2011-01-01

Background L-arabinose isomerases catalyse the isomerization of L-arabinose into L-ribulose at insight biological systems. At industrial scale of this enzyme is used for the bioconversion of D-galactose into D-tagatose which has many applications in pharmaceutical and agro-food industries. The isomerization reaction is thermodynamically equilibrated, and therefore the bioconversion rates is shifted towards tagatose when the temperature is increased. Moreover, to prevent secondary reactions it will be of interest to operate at low pH. The profitability of this D-tagatose production process is mainly related to the use of lactose as cheaper raw material. In many dairy products it will be interesting to produce D-tagatose during storage. This requires an efficient L-arabinose isomerase acting at low temperature and pH values. Results The gene encoding the L-arabinose isomerase from Shewanella sp. ANA-3 was cloned and overexpressed in Escherichia coli. The purified protein has a tetrameric arrangement composed by four identical 55 kDa subunits. The biochemical characterization of this enzyme showed that it was distinguishable by its maximal activity at low temperatures comprised between 15-35°C. Interestingly, this biocatalyst preserves more than 85% of its activity in a broad range of temperatures from 4.0 to 45°C. Shewanella sp. ANA-3 L-arabinose isomerase was also optimally active at pH 5.5-6.5 and maintained over 80% of its activity at large pH values from 4.0 to 8.5. Furthermore, this enzyme exhibited a weak requirement for metallic ions for its activity evaluated at 0.6 mM Mn2+. Stability studies showed that this protein is highly stable mainly at low temperature and pH values. Remarkably, T268K mutation clearly enhances the enzyme stability at low pH values. Use of this L-arabinose isomerase for D-tagatose production allows the achievement of attractive bioconversion rates of 16% at 4°C and 34% at 35°C. Conclusions Here we reported the purification and the

The acid-tolerant L-arabinose isomerase from the mesophilic Shewanella sp. ANA-3 is highly active at low temperatures

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Rhimi Moez

2011-11-01

Full Text Available Abstract Background L-arabinose isomerases catalyse the isomerization of L-arabinose into L-ribulose at insight biological systems. At industrial scale of this enzyme is used for the bioconversion of D-galactose into D-tagatose which has many applications in pharmaceutical and agro-food industries. The isomerization reaction is thermodynamically equilibrated, and therefore the bioconversion rates is shifted towards tagatose when the temperature is increased. Moreover, to prevent secondary reactions it will be of interest to operate at low pH. The profitability of this D-tagatose production process is mainly related to the use of lactose as cheaper raw material. In many dairy products it will be interesting to produce D-tagatose during storage. This requires an efficient L-arabinose isomerase acting at low temperature and pH values. Results The gene encoding the L-arabinose isomerase from Shewanella sp. ANA-3 was cloned and overexpressed in Escherichia coli. The purified protein has a tetrameric arrangement composed by four identical 55 kDa subunits. The biochemical characterization of this enzyme showed that it was distinguishable by its maximal activity at low temperatures comprised between 15-35°C. Interestingly, this biocatalyst preserves more than 85% of its activity in a broad range of temperatures from 4.0 to 45°C. Shewanella sp. ANA-3 L-arabinose isomerase was also optimally active at pH 5.5-6.5 and maintained over 80% of its activity at large pH values from 4.0 to 8.5. Furthermore, this enzyme exhibited a weak requirement for metallic ions for its activity evaluated at 0.6 mM Mn2+. Stability studies showed that this protein is highly stable mainly at low temperature and pH values. Remarkably, T268K mutation clearly enhances the enzyme stability at low pH values. Use of this L-arabinose isomerase for D-tagatose production allows the achievement of attractive bioconversion rates of 16% at 4°C and 34% at 35°C. Conclusions Here we

Differential response of aspen and birch trees to heat stress under elevated carbon dioxide

Energy Technology Data Exchange (ETDEWEB)

Darbah, Joseph N.T., E-mail: darbah@ohio.ed [School of Forest Resources and Environmental Science, Michigan Technological University, Houghton, MI 49931 (United States); Department of Environmental and Plant Biology, Ohio University, 315 Porter Hall, Athens, OH 45701 (United States); Sharkey, Thomas D. [Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824 (United States); Calfapietra, Carlo [Institute of Agro-Environmental and Forest Biology (IBAF), National Research Council (CNR), Via Salaria km 29300, 00016 Monterotondo Scalo, Roma (Italy); Karnosky, David F. [School of Forest Resources and Environmental Science, Michigan Technological University, Houghton, MI 49931 (United States)

2010-04-15

The effect of high temperature on photosynthesis of isoprene-emitting (aspen) and non-isoprene-emitting (birch) trees were measured under elevated CO{sub 2} and ambient conditions. Aspen trees tolerated heat better than birch trees and elevated CO{sub 2} protected photosynthesis of both species against moderate heat stress. Elevated CO{sub 2} increased carboxylation capacity, photosynthetic electron transport capacity, and triose phosphate use in both birch and aspen trees. High temperature (36-39 deg. C) decreased all of these parameters in birch regardless of CO{sub 2} treatment, but only photosynthetic electron transport and triose phosphate use at ambient CO{sub 2} were reduced in aspen. Among the two aspen clones tested, 271 showed higher thermotolerance than 42E possibly because of the higher isoprene-emission, especially under elevated CO{sub 2}. Our results indicate that isoprene-emitting trees may have a competitive advantage over non-isoprene emitting ones as temperatures rise, indicating that biological diversity may be affected in some ecosystems because of heat tolerance mechanisms. - We report that elevated CO{sub 2} confers increased thermotolerance on both aspen and birch trees while isoprene production in aspen confers further thermotolerance in aspen.

Differential response of aspen and birch trees to heat stress under elevated carbon dioxide

International Nuclear Information System (INIS)

Darbah, Joseph N.T.; Sharkey, Thomas D.; Calfapietra, Carlo; Karnosky, David F.

2010-01-01

The effect of high temperature on photosynthesis of isoprene-emitting (aspen) and non-isoprene-emitting (birch) trees were measured under elevated CO 2 and ambient conditions. Aspen trees tolerated heat better than birch trees and elevated CO 2 protected photosynthesis of both species against moderate heat stress. Elevated CO 2 increased carboxylation capacity, photosynthetic electron transport capacity, and triose phosphate use in both birch and aspen trees. High temperature (36-39 deg. C) decreased all of these parameters in birch regardless of CO 2 treatment, but only photosynthetic electron transport and triose phosphate use at ambient CO 2 were reduced in aspen. Among the two aspen clones tested, 271 showed higher thermotolerance than 42E possibly because of the higher isoprene-emission, especially under elevated CO 2 . Our results indicate that isoprene-emitting trees may have a competitive advantage over non-isoprene emitting ones as temperatures rise, indicating that biological diversity may be affected in some ecosystems because of heat tolerance mechanisms. - We report that elevated CO 2 confers increased thermotolerance on both aspen and birch trees while isoprene production in aspen confers further thermotolerance in aspen.

Novel therapeutic and prevention approaches for schistosomiasis: review.

Science.gov (United States)

El Ridi, Rashika A F; Tallima, Hatem A-M

2013-09-01

Schistosomiasis is a debilitating disease affecting approximately 600 million people in 74 developing countries, with 800 million, mostly children at risk. To circumvent the threat of having praziquantel (PZQ) as the only drug used for treatment, several PZQ derivatives were synthesized, and drugs destined for other parasites were used with success. A plethora of plant-derived oils and extracts were found to effectively kill juvenile and adult schistosomes, yet none was progressed to pre- and clinical studies except an oleo-gum resin extracted from the stem of Commiphora molmol, myrrh, which action was challenged in several trials. We have proposed an essential fatty acid, a component of our diet and cells, the polyunsaturated fatty acid arachidonic acid (ARA) as a remedy for schistosomiasis, due to its ability to activate the parasite tegument-bound neutral sphingomyelinase, with subsequent hydrolysis of the apical lipid bilayer sphingomyelin molecules, allowing access of specific antibody molecules, and eventual worm attrition. This concept was convincingly supported using larval and adult Schistosoma mansoni and Schistosoma haematobium worms in in vitro experiments, and in vivo studies in inbred mice and outbred hamsters. Even if ARA proves to be an entirely effective and safe therapy for schistosomiasis, it will not prevent reinfection, and accordingly, the need for developing an effective vaccine remains an urgent priority. Our studies have supported the status of S. mansoni calpain, glutathione-S-transferase, aldolase, triose phosphate isomerase, glyceraldehyde 3-phosphate dehydrogenase, enolase, and 2-cys peroxiredoxin as vaccine candidates, as they are larval excreted-secreted products and, contrary to the surface membrane molecules, are entirely accessible to the host immune system effector elements. We have proposed that the use of these molecules, in conjunction with Th2 cytokines-inducing adjuvants for recruiting and activating eosinophils and basophils

Novel Therapeutic and Prevention Approaches for Schistosomiasis: Review

Directory of Open Access Journals (Sweden)

Rashika A.F. El Ridi

2013-09-01

Full Text Available Schistosomiasis is a debilitating disease affecting approximately 600 million people in 74 developing countries, with 800 million, mostly children at risk. To circumvent the threat of having praziquantel (PZQ as the only drug used for treatment, several PZQ derivatives were synthesized, and drugs destined for other parasites were used with success. A plethora of plant-derived oils and extracts were found to effectively kill juvenile and adult schistosomes, yet none was progressed to pre- and clinical studies except an oleo-gum resin extracted from the stem of Commiphora molmol, myrrh, which action was challenged in several trials. We have proposed an essential fatty acid, a component of our diet and cells, the polyunsaturated fatty acid arachidonic acid (ARA as a remedy for schistosomiasis, due to its ability to activate the parasite tegument-bound neutral sphingomyelinase, with subsequent hydrolysis of the apical lipid bilayer sphingomyelin molecules, allowing access of specific antibody molecules, and eventual worm attrition. This concept was convincingly supported using larval and adult Schistosoma mansoni and Schistosoma haematobium worms in in vitro experiments, and in vivo studies in inbred mice and outbred hamsters. Even if ARA proves to be an entirely effective and safe therapy for schistosomiasis, it will not prevent reinfection, and accordingly, the need for developing an effective vaccine remains an urgent priority. Our studies have supported the status of S. mansoni calpain, glutathione-S-transferase, aldolase, triose phosphate isomerase, glyceraldehyde 3-phosphate dehydrogenase, enolase, and 2-cys peroxiredoxin as vaccine candidates, as they are larval excreted-secreted products and, contrary to the surface membrane molecules, are entirely accessible to the host immune system effector elements. We have proposed that the use of these molecules, in conjunction with Th2 cytokines-inducing adjuvants for recruiting and activating

Effects of polybrominated diphenyl ethers (PBDEs) and their derivatives on protein disulfide isomerase activity and growth hormone release of GH3 cells.

Science.gov (United States)

Hashimoto, Shoko; Yoshimura, Hiromi; Okada, Kazushi; Uramaru, Naoto; Sugihara, Kazumi; Kitamura, Shigeyuki; Imaoka, Susumu

2012-03-19

Polybrominated diphenyl ethers (PBDEs) have been used in a variety of consumer products such as flame retardants and recently have been known to be widespread environmental pollutants, which probably affect biological functions of mammalian cells. However, the risk posed by PBDE metabolites has not been clarified. Our previous study suggested that bisphenol A (BPA), an endocrine-disrupting chemical, binds to protein disulfide isomerase (PDI) and inhibits its activity. PDI is an isomerase enzyme in the endoplasmic reticulum and facilitates the formation or cleavage of disulfide bonds. PDI consists of a, b, b', and a' domains and the c region, with the a and a' domains having isomerase active sites. In the present study, we tested the effects of 10 kinds of PBDE compounds and their metabolites on PDI. OH-PBDEs specifically inhibited the isomerase activity of PDI, with 4'-OH-PBDE more effective than 2' (or 2)-OH-PBDEs. 4'-OH-PBDE inhibited the isomerase activity of the b'a'c fragment but not that of ab and a'c, suggesting that the b' domain of PDI is essential for the inhibition by 4'-OH-PBDE. We also investigated the effects of these chemicals on the production of growth hormone (GH) in GH3 cells. In GH3 cells, levels of mRNA and protein of GH stimulated by T(3) were reduced by 4'-OH-PBDE and 4'-MeO-PBDE. The reduction in GH expression caused by these compounds was not changed by the overexpression or knockdown of PDI in GH3 cells, while these manipulations of PDI levels significantly suppressed the expression of GH. These results suggest that the biological effects of PBDEs differed depending on their brominated and hydroxylated positions. © 2011 American Chemical Society

[Genetic profiling of Giardia intestinalis by polimerase chain in human and dogs samples of Colombian Caribean Coast].

Science.gov (United States)

Arroyo-Salgado, Bárbara; Buelvas-Montes, Yaleyvis; Villalba-Vizcaíno, Vivian; Salomón-Arzuza, Octavio

2014-01-01

Giardia intestinalis (G. Intestinalis) is a protozoan that causes diarrheal disease and malabsorption syndrome in humans and other mammals. It presents a high genetic diversity evidenced in the recognition of 7 genotypes (A-G). Genotypes A and B are commonly associated to humans and domestic animals such as dogs. The aim of this study was to conduct a preliminary genetic characterization of G. intestinalis in humans and dogs from two cities on the Caribbean coast of Colombia. Sampling areas were selected according to the highest numbers of acute diarrheal disease. Stool samples were collected from children under 7 years old, with positive medical tests for G. intestinalis. Cysts were purified by sucrose gradient and DNA samples were isolated by extraction with organic solvents. Molecular characterization was performed by amplifying the gene triose phosphate isomerase (tpi) by using a semi-nested PCR. A total of 202 samples of DNA were obtained; of these, 111 were positive in coproparasitological analysis (13 dogs and 98 children). Genotype distribution in positive samples was: 5.1% belonged to genotype A and 92.3% to genotype B. Genotype B was present in humans and animals. The most common genotype in both human and animal samples was genotype B, suggesting a zoonotic transmission cycle. Copyright © 2012 Elsevier España, S.L.U. y Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.

Search for gene mutations affecting protein structure in children of A-bomb survivors, 2

International Nuclear Information System (INIS)

Satoh, Chiyoko; Fujita, Mikio; Goriki, Kazuaki; Asakawa, Jun-ichi; Takahashi, Norio; Hamilton, H.B.; Hazama, Ryuji; Neel, J.V.

1984-01-01

Children who were born between May 1, 1946 and April 1, 1971 to survivor(s) exposed to A-bombing within 2,000 m from the hypocenter in Hiroshima and Nagasaki were selected as exposed group; their sex- and age-matched children born to survivor(s) who were exposed at 2,500 m or farther were selected as control group. When these children were in junior high school, mutation of protein structure was examined by using electrophoresis and by determining red cell enzymes with decreased activity and heat-unstable red cell enzymes. Electrophoretic study revealed a ''rare type of protein mutation'' in 635 of 12,242 individuals in the exposed group and in 448 of 10,154 individuals in the control group. The number of locuses in all proteins examined was calculated. The number of locuses per protein was corrected using the rate of parents' mutation type, and relative number of locuses were obtained. As a result, there was no difference in the mutation frequency per locus and generation between the exposed and control groups. Among children having red cell enzymes with decreased activity, mutant in triose phosphate isomerase was detected in one child in the exposed group, in whom electrophoretic pattern was normal and red cell enzymes were stable to heat. Heat-unstable red cell enzymes were seen in 9 children and their parents. However, family survey revealed genetic mutation in all instances irrespective of A-bombing. (Namekawa, K.)

The Path of Carbon in Photosynthesis. XXI. The Cyclic Regenerationof Carbon Dioxide Acceptor

Energy Technology Data Exchange (ETDEWEB)

Bassham, J.A.; Benson, A.A.; Kay, Lorel D.; Harris, Anne Z.; Wilson, A.T.; Calvin, M.

1953-10-01

Photosynthesizing plants have been exposed to C{sup 14}O{sub 2} for short periods of time (0.4 to 15 sec.) and the products of carbon dioxide reduction analyzed by paper chromatography and radio autography. Methods have been developed for the degradation of ribulose and sedoheptulose. These sugars, obtained as their phosphate esters from the above C{sup 14}O{sub 2} exposures and from other experiments, have been degraded and their distribution of radiocarbon determined. The distribution of radiocarbon in these sugars, and other data, indicate that sedoheptulose phosphate and ribulose diphosphates are formed during photosynthesis from triose and hexose phosphates, the latter being synthesized, in turn, by the reduction of 3-phosphoglyceric acid.

Structural Basis for Redox Regulation of Cytoplasmic and Chloroplastic Triosephosphate Isomerases from Arabidopsis thaliana

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Laura Margarita López-Castillo

2016-12-01

Full Text Available In plants triosephosphate isomerase (TPI interconverts glyceraldehyde 3-phosphate (G3P and dihydroxyacetone phosphate (DHAP during glycolysis, gluconeogenesis, and the Calvin-Benson cycle. The nuclear genome of land plants encodes two tpi genes, one gene product is located in the cytoplasm and the other is imported into the chloroplast. Herein we report the crystal structures of the TPIs from the vascular plant Arabidopsis thaliana (AtTPIs and address their enzymatic modulation by redox agents. Cytoplasmic TPI (cTPI and chloroplast TPI (pdTPI share more than 60% amino acid identity and assemble as (β-α8 dimers with high structural homology. cTPI and pdTPI harbor two and one accessible thiol groups per monomer respectively. cTPI and pdTPI present a cysteine at an equivalent structural position (C13 and C15 respectively and cTPI also contains a specific solvent accessible cysteine at residue 218 (cTPI-C218. Site directed mutagenesis of residues pdTPI-C15, cTPI-C13 and cTPI-C218 to serine substantially decreases enzymatic activity, indicating that the structural integrity of these cysteines is necessary for catalysis. AtTPIs exhibit differential responses to oxidative agents, cTPI is susceptible to oxidative agents such as diamide and H2O2, whereas pdTPI is resistant to inhibition. Incubation of AtTPIs with the sulfhydryl conjugating reagents methylmethane thiosulfonate (MMTS and glutathione inhibits enzymatic activity. However, the concentration necessary to inhibit pdTPI is at least two orders of magnitude higher than the concentration needed to inhibit cTPI. Western-blot analysis indicates that residues cTPI-C13, cTPI-C218, and pdTPI-C15 conjugate with glutathione. In summary, our data indicate that AtTPIs could be redox regulated by the derivatization of specific AtTPI cysteines (cTPI-C13 and pdTPI-C15 and cTPI-C218. Since AtTPIs have evolved by gene duplication, the higher resistance of pdTPI to redox agents may be an adaptive consequence to

Phospho-carboxyl-terminal domain binding and the role of a prolyl isomerase in pre-mRNA 3'-End formation.

Science.gov (United States)

Morris, D P; Phatnani, H P; Greenleaf, A L

1999-10-29

A phospho-carboxyl-terminal domain (CTD) affinity column created with yeast CTD kinase I and the CTD of RNA polymerase II was used to identify Ess1/Pin1 as a phospho-CTD-binding protein. Ess1/Pin1 is a peptidyl prolyl isomerase involved in both mitotic regulation and pre-mRNA 3'-end formation. Like native Ess1, a GSTEss1 fusion protein associates specifically with the phosphorylated but not with the unphosphorylated CTD. Further, hyperphosphorylated RNA polymerase II appears to be the dominant Ess1 binding protein in total yeast extracts. We demonstrate that phospho-CTD binding is mediated by the small WW domain of Ess1 rather than the isomerase domain. These findings suggest a mechanism in which the WW domain binds the phosphorylated CTD of elongating RNA polymerase II and the isomerase domain reconfigures the CTD though isomerization of proline residues perhaps by a processive mechanism. This process may be linked to a variety of pre-mRNA maturation events that use the phosphorylated CTD, including the coupled processes of pre-mRNA 3'-end formation and transcription termination.

Nucleotide sequence of the triosephosphate isomerase gene from Macaca mulatta

Energy Technology Data Exchange (ETDEWEB)

Old, S.E.; Mohrenweiser, H.W. (Univ. of Michigan, Ann Arbor (USA))

1988-09-26

The triosephosphate isomerase gene from a rhesus monkey, Macaca mulatta, charon 34 library was sequenced. The human and chimpanzee enzymes differ from the rhesus enzyme at ASN 20 and GLU 198. The nucleotide sequence identity between rhesus and human is 97% in the coding region and >94% in the flanking regions. Comparison of the rhesus and chimp genes, including the intron and flanking sequences, does not suggest a mechanism for generating the two TPI peptides of proliferating cells from hominoids and a single peptide from the rhesus gene.

l-Arabinose Isomerase and d-Xylose Isomerase from Lactobacillus reuteri: Characterization, Coexpression in the Food Grade Host Lactobacillus plantarum, and Application in the Conversion of d-Galactose and d-Glucose

Science.gov (United States)

2014-01-01

The l-arabinose isomerase (l-AI) and the d-xylose isomerase (d-XI) encoding genes from Lactobacillus reuteri (DSMZ 17509) were cloned and overexpressed in Escherichia coli BL21 (DE3). The proteins were purified to homogeneity by one-step affinity chromatography and characterized biochemically. l-AI displayed maximum activity at 65 °C and pH 6.0, whereas d-XI showed maximum activity at 65 °C and pH 5.0. Both enzymes require divalent metal ions. The genes were also ligated into the inducible lactobacillal expression vectors pSIP409 and pSIP609, the latter containing a food grade auxotrophy marker instead of an antibiotic resistance marker, and the l-AI- and d-XI-encoding sequences/genes were coexpressed in the food grade host Lactobacillus plantarum. The recombinant enzymes were tested for applications in carbohydrate conversion reactions of industrial relevance. The purified l-AI converted d-galactose to d-tagatose with a maximum conversion rate of 35%, and the d-XI isomerized d-glucose to d-fructose with a maximum conversion rate of 48% at 60 °C. PMID:24443973

Biochemical properties of L-arabinose isomerase from Clostridium hylemonae to produce D-tagatose as a functional sweetener.

Science.gov (United States)

Nguyen, Tien-Kieu; Hong, Moon-Gi; Chang, Pahn-Shick; Lee, Byung-Hoo; Yoo, Sang-Ho

2018-01-01

d-Tagatose has gained substantial interest due to its potential functionalities as a sucrose substitute. In this study, the gene araA, encoding l-arabinose isomerase (l-AI) from Clostridium hylemonae (DSM 15053), was cloned and expressed in Escherichia coli BL21 (DE3). This gene consists of 1,506 nucleotides and encodes a protein of 501 amino acid residues with a calculated molecular mass of 56,554 Da. Since l-AI was expressed as an intracellular inclusion body, this enzyme was solubilized with guanidine hydrochloride, refolded, and activated with a descending concentration gradient of urea. The purified enzyme exhibited the greatest activity at 50°C, pH 7-7.5, and required 1 mM of Mg2+ as a cofactor. Notably, the catalytic efficiency (3.69 mM-1sec-1) of l-AI from C. hylemonae on galactose was significantly greater than that of other previously reported enzymes. The bioconversion yield of d-tagatose using the C. hylemonae l-arabinose isomerase at 60°C reached approximately 46% from 10 mM of d-galactose after 2 h. From these results, it is suggested that the l-arabinose isomerase from C. hylemonae could be utilized as a potential enzyme for d-tagatose production due to its high conversion yield at an industrially competitive temperature.

Rational design of Bacillus stearothermophilus US100 L-arabinose isomerase: potential applications for D-tagatose production.

Science.gov (United States)

Rhimi, Moez; Aghajari, Nushin; Juy, Michel; Chouayekh, Hichem; Maguin, Emmanuelle; Haser, Richard; Bejar, Samir

2009-05-01

L-arabinose isomerases catalyze the bioconversion of D-galactose into D-tagatose. With the aim of producing an enzyme optimized for D-tagatose production, three Bacillus stearothermophilus US100 L-arabinose isomerase mutants were constructed, purified and characterized. Our results indicate that mutant Q268K was significantly more acidotolerant and more stable at acidic pH than the wild-type enzyme. The N175H mutant has a broad optimal temperature range from 50 to 65 degrees C. With the aim of constructing an acidotolerant mutant working at relatively low temperatures we generated the Q268K/N175H construct. This double mutant displays an optimal pH in the range 6.0-7.0 and an optimal activity around 50-65 degrees C, temperatures at which the enzyme was stable without addition of metal ions.

Theileria parasites secrete a prolyl isomerase to maintain host leukocyte transformation.

Science.gov (United States)

Marsolier, J; Perichon, M; DeBarry, J D; Villoutreix, B O; Chluba, J; Lopez, T; Garrido, C; Zhou, X Z; Lu, K P; Fritsch, L; Ait-Si-Ali, S; Mhadhbi, M; Medjkane, S; Weitzman, J B

2015-04-16

Infectious agents develop intricate mechanisms to interact with host cell pathways and hijack their genetic and epigenetic machinery to change host cell phenotypic states. Among the Apicomplexa phylum of obligate intracellular parasites, which cause veterinary and human diseases, Theileria is the only genus that transforms its mammalian host cells. Theileria infection of bovine leukocytes induces proliferative and invasive phenotypes associated with activated signalling pathways, notably JNK and AP-1 (ref. 2). The transformed phenotypes are reversed by treatment with the theilericidal drug buparvaquone. We used comparative genomics to identify a homologue of the peptidyl-prolyl isomerase PIN1 in T. annulata (TaPIN1) that is secreted into the host cell and modulates oncogenic signalling pathways. Here we show that TaPIN1 is a bona fide prolyl isomerase and that it interacts with the host ubiquitin ligase FBW7, leading to its degradation and subsequent stabilization of c-JUN, which promotes transformation. We performed in vitro and in silico analysis and in vivo zebrafish xenograft experiments to demonstrate that TaPIN1 is directly inhibited by the anti-parasite drug buparvaquone (and other known PIN1 inhibitors) and is mutated in a drug-resistant strain. Prolyl isomerization is thus a conserved mechanism that is important in cancer and is used by Theileria parasites to manipulate host oncogenic signalling.

Inhibiting prolyl isomerase activity by hybrid organic-inorganic molecules containing rhodium(II) fragments.

Science.gov (United States)

Coughlin, Jane M; Kundu, Rituparna; Cooper, Julian C; Ball, Zachary T

2014-11-15

A small molecule containing a rhodium(II) tetracarboxylate fragment is shown to be a potent inhibitor of the prolyl isomerase FKBP12. The use of small molecules conjugates of rhodium(II) is presented as a general strategy for developing new protein inhibitors based on distinct structural and sequence features of the enzyme active site. Copyright © 2014 Elsevier Ltd. All rights reserved.

Ethanol production from lignocellulosic hydrolysates using engineered Saccharomyces cerevisiae harboring xylose isomerase-based pathway.

Science.gov (United States)

Ko, Ja Kyong; Um, Youngsoon; Woo, Han Min; Kim, Kyoung Heon; Lee, Sun-Mi

2016-06-01

The efficient co-fermentation of glucose and xylose is necessary for the economically feasible bioethanol production from lignocellulosic biomass. Even with xylose utilizing Saccharomyces cerevisiae, the efficiency of the lignocellulosic ethanol production remains suboptimal mainly due to the low conversion yield of xylose to ethanol. In this study, we evaluated the co-fermentation performances of SXA-R2P-E, a recently engineered isomerase-based xylose utilizing strain, in mixed sugars and in lignocellulosic hydrolysates. In a high-sugar fermentation with 70g/L of glucose and 40g/L of xylose, SXA-R2P-E produced 50g/L of ethanol with an yield of 0.43gethanol/gsugars at 72h. From dilute acid-pretreated hydrolysates of rice straw and hardwood (oak), the strain produced 18-21g/L of ethanol with among the highest yield of 0.43-0.46gethanol/gsugars ever reported. This study shows a highly promising potential of a xylose isomerase-expressing strain as an industrially relevant ethanol producer from lignocellulosic hydrolysates. Copyright © 2016 Elsevier Ltd. All rights reserved.

In-house SIRAS phasing of the polyunsaturated fatty-acid isomerase from Propionibacterium acnes

International Nuclear Information System (INIS)

Liavonchanka, Alena; Hornung, Ellen; Feussner, Ivo; Rudolph, Markus

2006-01-01

Low iodide concentrations were sufficient to allow SAD and SIRAS phasing of cubic crystals of a novel fatty acid isomerase using Cu Kα radiation. The polyenoic fatty-acid isomerase from Propionibacterium acnes (PAI) catalyzes the double-bond isomerization of linoleic acid to conjugated linoleic acid, which is a dairy- or meat-derived fatty acid in the human diet. PAI was overproduced in Escherichia coli and purified to homogeneity as a yellow-coloured protein. The nature of the bound cofactor was analyzed by absorption and fluorescence spectroscopy. Single crystals of PAI were obtained in two crystal forms. Cubic shaped crystals belong to space group I2 1 3, with a unit-cell parameter of 160.4 Å, and plate-like crystals belong to the monoclinic space group C2, with unit-cell parameters a = 133.7, b = 60.8, c = 72.2 Å, β = 115.8°. Both crystal forms contain one molecule per asymmetric unit and diffract to a resolution of better than 2.0 Å. Initial phases were obtained by SIRAS from in-house data from a cubic crystal that was soaked with an unusually low KI concentration of 0.25 M

A Protein Disulfide Isomerase Gene Fusion Expression System That Increases the Extracellular Productivity of Bacillus brevis

Science.gov (United States)

Kajino, Tsutomu; Ohto, Chikara; Muramatsu, Masayoshi; Obata, Shusei; Udaka, Shigezo; Yamada, Yukio; Takahashi, Haruo

2000-01-01

We have developed a versatile Bacillus brevis expression and secretion system based on the use of fungal protein disulfide isomerase (PDI) as a gene fusion partner. Fusion with PDI increased the extracellular production of heterologous proteins (light chain of immunoglobulin G, 8-fold; geranylgeranyl pyrophosphate synthase, 12-fold). Linkage to PDI prevented the aggregation of the secreted proteins, resulting in high-level accumulation of fusion proteins in soluble and biologically active forms. We also show that the disulfide isomerase activity of PDI in a fusion protein is responsible for the suppression of the aggregation of the protein with intradisulfide, whereas aggregation of the protein without intradisulfide was prevented even when the protein was fused to a mutant PDI whose two active sites were disrupted, suggesting that another PDI function, such as chaperone-like activity, synergistically prevented the aggregation of heterologous proteins in the PDI fusion expression system. PMID:10653729

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

Directory of Open Access Journals (Sweden)

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

The basic tilted helix bundle domain of the prolyl isomerase FKBP25 is a novel double-stranded RNA binding module

Science.gov (United States)

Dilworth, David; Bonnafous, Pierre; Edoo, Amiirah Bibi; Bourbigot, Sarah; Pesek-Jardim, Francy; Gudavicius, Geoff; Serpa, Jason J.; Petrotchenko, Evgeniy V.; Borchers, Christoph H.

2017-01-01

Abstract Prolyl isomerases are defined by a catalytic domain that facilitates the cis–trans interconversion of proline residues. In most cases, additional domains in these enzymes add important biological function, including recruitment to a set of protein substrates. Here, we report that the N-terminal basic tilted helix bundle (BTHB) domain of the human prolyl isomerase FKBP25 confers specific binding to double-stranded RNA (dsRNA). This binding is selective over DNA as well as single-stranded oligonucleotides. We find that FKBP25 RNA-association is required for its nucleolar localization and for the vast majority of its protein interactions, including those with 60S pre-ribosome and early ribosome biogenesis factors. An independent mobility of the BTHB and FKBP catalytic domains supports a model by which the N-terminus of FKBP25 is anchored to regions of dsRNA, whereas the FKBP domain is free to interact with neighboring proteins. Apart from the identification of the BTHB as a new dsRNA-binding module, this domain adds to the growing list of auxiliary functions used by prolyl isomerases to define their primary cellular targets. PMID:29036638

Structural insights from a novel invertebrate triosephosphate isomerase from Litopenaeus vannamei

Science.gov (United States)

Lopez-Zavala, Alonso A.; Carrasco-Miranda, Jesus S.; Ramirez-Aguirre, Claudia D.; López-Hidalgo, Marisol; Benitez-Cardoza, Claudia G.; Ochoa-Leyva, Adrian; Cardona-Felix, Cesar S.; Diaz-Quezada, Corina; Rudiño-Piñera, Enrique; Sotelo-Mundo, Rogerio R.; Brieba, Luis G.

2016-01-01

Triosephosphate isomerase (TIM; EC 5.3.1.1) is a key enzyme involved in glycolysis and gluconeogenesis. Glycolysis is one of the most regulated metabolic pathways, however little is known about the structural mechanisms for its regulation in non-model organisms, like crustaceans. To understand the structure and function of this enzyme in invertebrates, we obtained the crystal structure of triosephosphate isomerase from the marine Pacific whiteleg shrimp (Litopenaeus vannamei, LvTIM) in complex with its inhibitor 2-phosphogyceric acid (2-PG) at 1.7 Å resolution. LvTIM assembles as a homodimer with residues 166-176 covering the active site and residue Glu166 interacting with the inhibitor. We found that LvTIM is the least stable TIM characterized to date, with the lowest range of melting temperatures, and with the lowest activation enthalpy associated with the thermal unfolding process reported. In TIMs dimer stabilization is maintained by an interaction of loop 3 by a set of hydrophobic contacts between subunits. Within these contacts, the side chain of a hydrophobic residue of one subunit fits into a cavity created by a set of hydrophobic residues in the neighboring subunit, via a "ball and socket" interaction. LvTIM presents a Cys47 at the "ball" inter-subunit contact indicating that the character of this residue is responsible for the decrease in dimer stability. Mutational studies show that this residue plays a role in dimer stability but is not a solely determinant for dimer formation. PMID:27614148

Effect of gamma irradiation on whole-cell glucose isomerase. Pt.1

International Nuclear Information System (INIS)

Bachman, S.; Gebicka, L.

1984-01-01

Gamma-rays induced inactivation of Actinoplanes missouriensis and Streptomyces olivaceus glucose isomerase has been studied. This enzyme exhibits high resistance against ionizing radiation. The D 37 value was found to be equal to 131 kGy for Actinoplanes missouriensis cells and 88 kGy for Streptomyces olivaceus cells when irradiated in the dry state in the presence of air. Mg 2+ ions do not affect the radiosensitivity of the enzyme in cells, while the addition of Co 2+ ions to the cell suspension increases its stability against ionizing radiation. (orig.) [de

Production of D-tagatose, a low caloric sweetener during milk fermentation using L-arabinose isomerase.

Science.gov (United States)

Rhimi, Moez; Chouayekh, Hichem; Gouillouard, Isabelle; Maguin, Emmanuelle; Bejar, Samir

2011-02-01

Lactobacillusdelbrueckii subsp. bulgaricus and Streptococcus thermophilus are used for the biotransformation of milk in yoghurt. During milk fermentation, these lactic acid bacteria (LAB) hydrolyze lactose producing a glucose moiety that is further metabolized and a galactose moiety that they are enable to metabolize. We investigated the ability of L. bulgaricus and S. thermophilus strains expressing a heterologous L-arabinose isomerase to convert residual D-galactose to D-tagatose. The Bacillus stearothermophilus US100l-arabinose isomerase (US100l-AI) was expressed in both LAB, using a new shuttle vector where the araA US100 gene is under the control of the strong and constitutive promoter of the L. bulgaricus ATCC 11842 hlbA gene. The production of L-AI by these LAB allowed the bioconversion of D-galactose to D-tagatose during fermentation in laboratory media and milk. We also established that the addition of L-AI to milk also allowed the conversion of D-galactose into D-tagatose during the fermentation process. Copyright © 2010 Elsevier Ltd. All rights reserved.

Compact conformations of human protein disulfide isomerase.

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Shang Yang

Full Text Available Protein disulfide isomerase (PDI composed of four thioredoxin-like domains a, b, b', and a', is a key enzyme catalyzing oxidative protein folding in the endoplasmic reticulum. Large scale molecular dynamics simulations starting from the crystal structures of human PDI (hPDI in the oxidized and reduced states were performed. The results indicate that hPDI adopts more compact conformations in solution than in the crystal structures, which are stabilized primarily by inter-domain interactions, including the salt bridges between domains a and b' observed for the first time. A prominent feature of the compact conformations is that the two catalytic domains a and a' can locate close enough for intra-molecular electron transfer, which was confirmed by the characterization of an intermediate with a disulfide between the two domains. Mutations, which disrupt the inter-domain interactions, lead to decreased reductase activity of hPDI. Our molecular dynamics simulations and biochemical experiments reveal the intrinsic conformational dynamics of hPDI and its biological impact.

The crystal structure of a multifunctional protein: Phosphoglucose isomerase/autocrine motility factor/neuroleukin

OpenAIRE

Sun, Yuh-Ju; Chou, Chia-Cheng; Chen, Wei-Shone; Wu, Rong-Tsun; Meng, Menghsiao; Hsiao, Chwan-Deng

1999-01-01

Phosphoglucose isomerase (PGI) plays a central role in both the glycolysis and the gluconeogenesis pathways. We present here the complete crystal structure of PGI from Bacillus stearothermophilus at 2.3-Å resolution. We show that PGI has cell-motility-stimulating activity on mouse colon cancer cells similar to that of endogenous autocrine motility factor (AMF). PGI can also enhance neurite outgrowth on neuronal progenitor cells similar to that observed for neuroleukin. The results confirm tha...

The Path of Carbon in Photosynthesis XVIII. The Identification of Nucleotide Coenzymes

Science.gov (United States)

Buchanan, J. G.; Lynch, V. H.; Benson, A. A.; Calvin, M.; Bradley, D. F.

1953-01-19

The radioactive compounds to be observed when algae or green leaves are allowed to photosynthesize in C{sup 14}O{sub 2} for short periods are almost all phosphorylated derivatives of sugars. Of these, phosphate esters of trioses, sedoheptulose and fructose are the first to incorporate C{sup 14} followed closely by ribulose diphosphate, glucose-6-phosphate and a phosphate of mannose. It has been noted, in earlier papers of this series, that on radiograms of the products of photosynthesis, a dark area appeared in a position occupied by no known sugar phosphate and which gave glucose on acid hydrolysis or on treatment with a phosphatase preparation. This has hitherto been referred to as an 'unknown glucose phosphate'. It was found that this substance was more labile to acid than glucose-l-phosphate, itself a readily hydrolysable phosphate, and furthermore that other labile glucose derivatives were formed as intermediates during the acid hydrolysis. Accumulation of labeled glucose in this area precedes that in sucrose and suggests its synthetic relationship to sucrose phosphate synthesis.

Crystallization and preliminary X-ray crystallographic analysis of l-rhamnose isomerase with a novel high thermostability from Bacillus halodurans

International Nuclear Information System (INIS)

Doan, Thi-Ngoc-Thanh; Prabhu, Ponnandy; Kim, Jin-Kwang; Ahn, Yeh-Jin; Natarajan, Sampath; Kang, Lin-Woo; Park, Geon Tae; Lim, Sang-Boem; Lee, Jung-Kul

2010-01-01

l-Rhamnose isomerase (l-RhI) from B. halodurans has been purified and crystallized. The crystals of l-RhI belonged to the monoclinic space group P2 1 , with unit-cell parameters a = 83.2, b = 164.9, c = 92.0 Å, β = 116.0°, and diffracted to 2.5 Å resolution. l-Rhamnose isomerases catalyze isomerization between l-rhamnose (6-deoxy-l-mannose) and l-rhamnulose (6-deoxy-l-fructose), which is the first step in rhamnose catabolism. l-Rhamnose isomerase from Bacillus halodurans ATCC BAA-125 (BHRI) exhibits interesting characteristics such as high thermostability and selective substrate specificity. BHRI fused with an HHHHHH sequence was purified and crystallized in order to elucidate the molecular basis of its unique enzymatic properties. The crystals were grown by the hanging-drop vapour-diffusion method and belonged to the monoclinic space group P2 1 , with unit-cell parameters a = 83.2, b = 164.9, c = 92.0 Å, β = 116.0°. Diffraction data were collected to 2.5 Å resolution. According to a Matthews coefficient calculation, there are four monomers in the asymmetric unit with a V M of 3.0 Å 3 Da −1 and a solvent content of 59.3%. The initial structure of BHRI has been determined by the molecular-replacement method

Pnp gene modification for improved xylose utilization in Zymomonas

Science.gov (United States)

Caimi, Perry G G; Qi, Min; Tao, Luan; Viitanen, Paul V; Yang, Jianjun

2014-12-16

The endogenous pnp gene encoding polynucleotide phosphorylase in the Zymomonas genome was identified as a target for modification to provide improved xylose utilizing cells for ethanol production. The cells are in addition genetically modified to have increased expression of ribose-5-phosphate isomerase (RPI) activity, as compared to cells without this genetic modification, and are not limited in xylose isomerase activity in the absence of the pnp modification.

The peptidyl prolyl cis/trans isomerase Pin1/Ess1 inhibits phosphorylation and toxicity of tau in a yeast model for Alzheimer’s disease

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Ann De Vos

2015-04-01

Full Text Available Since hyperphosphorylation of protein tau is a crucial event in Alzheimer’s disease, additional mechanisms besides the interplay of kinase and phosphatase activities are investigated, such as the effect of the peptidyl prolyl cis/trans isomerase Pin1. This isomerase was shown to bind and isomerize phosphorylated protein tau, thereby restoring the microtubule associated protein function of tau as well as promoting the dephosphorylation of the protein by the trans-dependent phosphatase PP2A. In this study we used models based on Saccharomyces cerevisiae to further elucidate the influence of Pin1 and its yeast ortholog Ess1 on tau phosphorylation and self-assembly. We could demonstrate that in yeast, a lack of Pin1 isomerase activity leads to an increase in phosphorylation of tau at Thr231, comparable to AD brain and consistent with earlier findings in other model organisms. However, we could also distinguish an effect by Pin1 on other residues of tau, i.e. Ser235 and Ser198/199/202. Furthermore, depletion of Pin1 isomerase activity results in reduced growth of the yeast cells, which is enhanced upon expression of tau. This suggests that the accumulation of hyperphosphorylated and aggregation-prone tau causes cytotoxicity in yeast. This study introduces yeast as a valuable model organism to characterize in detail the effect of Pin1 on the biochemical characteristics of protein tau, more specifically its phosphorylation and aggregation.

Mechanism of ultraviolet light induced catabolite repression of L-arabinose isomerase

Energy Technology Data Exchange (ETDEWEB)

Bhatnagar, D; Bhattacharya, A K [Banaras Hindu Univ. (India). Inst. of Medical Sciences

1982-12-01

An attempt has been made to find out how U.V. irradiation of E.coli B/r cells causes catabolite repression to inhibit L-arabinose isomerase synthesis. The results presented show that U.V. irradiation leads to a lowering of the cellular cyclic AMP level and of the cyclic AMP binding activity. Unlike catabolite repression by glucose, no small molecular weight compound is involved in U.V. light induced inhibition of the binding activity. It is therefore concluded that the mechanism of catabolite repression induced by U.V. appears to be different from that of the catabolite repression by glucose.

Occurrence and molecular characterization of Giardia duodenalis and Cryptosporidium spp. in sheep and goats reared under dairy husbandry systems in Greece☆

Science.gov (United States)

Tzanidakis, Nikolaos; Sotiraki, Smaragda; Claerebout, Edwin; Ehsan, Amimul; Voutzourakis, Nikolaos; Kostopoulou, Despoina; Stijn, Casaert; Vercruysse, Jozef; Geurden, Thomas

2014-01-01

Giardia duodenalis and Cryptosporidium spp. are gastro-intestinal protozoa known to infect small ruminants. Both protozoa are also considered as a potential public health concern. The objective of this study was to determine their prevalence in lambs and goat kids kept under common Mediterranean dairy husbandry systems and to identify the species and genotypes infecting these small ruminants. In total, 684 faecal samples (429 from lambs and 255 from goat kids) were collected on 21 farms in Greece and examined using a quantitative immunofluorescence assay. G. duodenalis was detected in 37.3% of the lambs and 40.4% of the goat kids. On all but one of the farms G. duodenalis was detected. Most samples were typed as a mono-infection with G. duodenalis assemblage E, both on the β-giardin gene and the triose phosphate isomerase gene. Only 10% of samples were typed as mixed assemblage A and E infections. The prevalence of Cryptosporidium spp. was 5.1% in lambs and 7.1% in goat kids. In total, 8 out of the 14 farms with a sheep flock and 7 out of the 14 farms with a goat flock were positive. Cryptosporidium parvum (subtype IId), C. ubiquitum and C. xiaoi were identified, the latter especially in goat kids. In conclusion, the results of the present study illustrate that G. duodenalis and Cryptosporidium spp. occur frequently on both sheep and goats farms. The prevalence of zoonotic genotypes or species was low, indicating a limited but existing risk for zoonotic infections. PMID:25187088

Characterization of a monoclonal antibody that specifically inhibits triosephosphate isomerase activity of Taenia solium.

Science.gov (United States)

Víctor, Sanabria-Ayala; Yolanda, Medina-Flores; Araceli, Zavala-Carballo; Lucía, Jiménez; Abraham, Landa

2013-08-01

In the present study, we obtained and characterized partially a monoclonal antibody (4H11D10B11 mAb) against triosephosphate isomerase from Taenia solium (TTPI). This antibody recognized the enzyme by both ELISA and western blot and was able to inhibit its enzymatic activity in 74%. Moreover, the antigen-binding fragments (Fabs), products of digestion of the monoclonal antibody with papain, retained almost the same inhibitory effect. We determined the binding site by ELISA; synthetic peptides containing sequences from different non-conserved regions of the TTPI were confronted to the 4H11D10B11 mAb. The epitope recognized by the monoclonal antibody was located on peptide TTPI-56 (ATPAQAQEVHKVVRDWIRKHVDAGIADKARI), and an analysis of mimotopes, obtained with the 4H11D10B11 mAb, suggests that the epitope spans the sequence WIRKHVDAGIAD, residues 193-204 of the enzyme. This epitope is located within helix 6, next to loop 6, an essential active loop during catalysis. The antibody did not recognize triosephosphate isomerase from man and pig, definitive and intermediary hosts of T. solium, respectively. Furthermore, it did not bind to the catalytic site, since kinetic analysis demonstrated that inhibition had a non-competitive profile. Copyright © 2013 Elsevier Inc. All rights reserved.

A dual inhibitor against prolyl isomerase Pin1 and cyclophilin discovered by a novel real-time fluorescence detection method

International Nuclear Information System (INIS)

Mori, Tadashi; Hidaka, Masafumi; Lin, Yi-Chin; Yoshizawa, Ibuki; Okabe, Takayoshi; Egashira, Shinichiro; Kojima, Hirotatsu; Nagano, Tetsuo; Koketsu, Mamoru; Takamiya, Mari; Uchida, Takafumi

2011-01-01

Research highlights: → A Pin1 (prolyl isomerase) inhibitor, TME-001, has been discovered by using a new established high-throughput screening method. → The TME-001 showed a cell-active inhibition with lower cytotoxic effect than known Pin1 inhibitors. → Kinetic analyses revealed that the TME-001 is the first compound that exhibits dual inhibition of Pin1 and another type of prolyl isomerase, cyclophilin. → Thus, similarities of structure and reaction mechanism between Pin1 and cyclophilin are proposed. -- Abstract: Pin1, a peptidyl prolyl cis/trans isomerase (PPIase), is a potential target molecule for cancer, infectious disease, and Alzheimer's disease. We established a high-throughput screening method for Pin1 inhibitors, which employs a real-time fluorescence detector. This screening method identified 66 compounds that inhibit Pin1 out of 9756 compounds from structurally diverse chemical libraries. Further evaluations of surface plasmon resonance methods and a cell proliferation assay were performed. We discovered a cell-active inhibitor, TME-001 (2-(3-chloro-4-fluoro-phenyl)-isothiazol-3-one). Surprisingly, kinetic analyses revealed that TME-001 is the first compound that exhibits dual inhibition of Pin1 (IC 50 = 6.1 μM) and cyclophilin, another type of PPIase, (IC 50 = 13.7 μM). This compound does not inhibit FKBP. This finding suggests the existence of similarities of structure and reaction mechanism between Pin1 and cyclophilin, and may lead to a more complete understanding of the active sites of PPIases.

ORF Alignment: NC_000913 [GENIUS II[Archive

Lifescience Database Archive (English)

Full Text Available amine-6-Phosphate ... Deaminase From E.Coli, T Conformer, At 1.9a Resolution ... pdb|1FS6|A Ch...ain A, Glucosamine-6-Phosphate Deaminase ... From E.Coli, T Conformer, At ...phate Isomerase pdb|1FRZ|B Chain B, ... Glucosamine-6-Phosphate Deaminase From E.Coli, R ... C...lution ... pdb|1FRZ|A Chain A, Glucosamine-6-Phosphate Deaminase ... From E.Coli, R Conformer....hate At 2.2 A ... Resolution pdb|1CD5|A Chain A, Glucosamine-6-Phosphate ... Deaminase From E.Coli

Association of a multi-synthetase complex with translating ribosomes in the archaeon Thermococcus kodakarensis

DEFF Research Database (Denmark)

Raina, Medha; Elgamal, Sara; Santangelo, Thomas J

2012-01-01

-dependent methyltransferase 144, GTP cyclohydrolase 398, DNA topoisomerase VI subunit A 209, DNA topoisomerase VI subunit B 192, Type A Flavoprotein 911, NAD(P)H:rubredoxin oxidoreductase (Fatty acid metabolism) 120, NAD(P)H:rubredoxin oxidoreductase 120, cofactor-independent phosphoglycerate mutase 909, bis(5'-adenosyl...... subunit 2 255, glycerol kinase 257, phosphomannomutase-related protein 321, ribose-5-phosphate isomerase A 107, phosphate transport regulator 193, isopentenyl pyrophosphate isomerase (mevanolate Pathway) 500, amino acid kinase 203, NADH:polysulfide oxidoreductase 203, 5'-methylthioadenosine phosphorylase......, cysteine desulfurase 521, hydrogenase maturation protein HypF 235, iron-molybdenum cofactor-binding protein 192, ATPase 260, 4Fe-4S cluster-binding protein 254, phosphopyruvate hydratase 650, fructose-1,6-bisphosphatase 140, aspartate carbamoyltransferase catalytic subunit 158, Bipolar DNA helicase 448...

The multidrug resistance IncA/C transferable plasmid encodes a novel domain-swapped dimeric protein-disulfide isomerase.

Science.gov (United States)

Premkumar, Lakshmanane; Kurth, Fabian; Neyer, Simon; Schembri, Mark A; Martin, Jennifer L

2014-01-31

The multidrug resistance-encoding IncA/C conjugative plasmids disseminate antibiotic resistance genes among clinically relevant enteric bacteria. A plasmid-encoded disulfide isomerase is associated with conjugation. Sequence analysis of several IncA/C plasmids and IncA/C-related integrative and conjugative elements (ICE) from commensal and pathogenic bacteria identified a conserved DsbC/DsbG homolog (DsbP). The crystal structure of DsbP reveals an N-terminal domain, a linker region, and a C-terminal catalytic domain. A DsbP homodimer is formed through domain swapping of two DsbP N-terminal domains. The catalytic domain incorporates a thioredoxin-fold with characteristic CXXC and cis-Pro motifs. Overall, the structure and redox properties of DsbP diverge from the Escherichia coli DsbC and DsbG disulfide isomerases. Specifically, the V-shaped dimer of DsbP is inverted compared with EcDsbC and EcDsbG. In addition, the redox potential of DsbP (-161 mV) is more reducing than EcDsbC (-130 mV) and EcDsbG (-126 mV). Other catalytic properties of DsbP more closely resemble those of EcDsbG than EcDsbC. These catalytic differences are in part a consequence of the unusual active site motif of DsbP (CAVC); substitution to the EcDsbC-like (CGYC) motif converts the catalytic properties to those of EcDsbC. Structural comparison of the 12 independent subunit structures of DsbP that we determined revealed that conformational changes in the linker region contribute to mobility of the catalytic domain, providing mechanistic insight into DsbP function. In summary, our data reveal that the conserved plasmid-encoded DsbP protein is a bona fide disulfide isomerase and suggest that a dedicated oxidative folding enzyme is important for conjugative plasmid transfer.

Genome sequence of carboxylesterase, carboxylase and xylose isomerase producing alkaliphilic haloarchaeon Haloterrigena turkmenica WANU15

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Samy Selim

2016-03-01

Full Text Available We report draft genome sequence of Haloterrigena turkmenica strain WANU15, isolated from Soda Lake. The draft genome size is 2,950,899 bp with a G + C content of 64% and contains 49 RNA sequence. The genome sequence can be accessed at DDBJ/EMBL/GenBank under the accession no. LKCV00000000. Keywords: Soda Lake, Haloterrigena turkmenica, Carboxylesterase, Carboxylase, Xylose isomerase, Whole genome sequencing

Revisiting the mechanistic basis of the French Paradox: red wine inhibits the activity of protein disulfide isomerase in vitro

Science.gov (United States)

Galinski, Christine N.; Zwicker, Jeffrey I.; Kennedy, Daniel R.

2015-01-01

Introduction Although epidemiologic evidence points to cardioprotective activity of red wine, the mechanistic basis for antithrombotic activity has not been established. Quercetin and related flavonoids are present in high concentrations in red but not white wine. Quercetin-glycosides were recently shown to prevent thrombosis in animal models through the inhibition of extracellular protein disulfide isomerase (PDI). We evaluated whether red or white wine inhibited PDI activity in vitro. Methods Quercetin levels in red and white wines were measured by HPLC analysis. Inhibition of PDI activity by red and white wines was assessed by an insulin reduction turbidity assay at various concentrations of wine. PDI inhibition was confirmed using a reduced peptide that contained a disulfide containing peptide as a substrate. The inhibition of PDI related thiol isomerases ERp5 and ERp57 was also assessed. Results We observed a dose-dependent decrease of PDI activity for a variety of red but not white wines. Red wine diluted to 3% final concentration resulted in over 80% inhibition of PDI activity by insulin reductase assay for all varieties tested. This inhibition was also observed in the peptide based assay. Red grape juice yielded similar results but ethanol alone did not affect PDI activity. Interestingly, red wine also inhibited the PDI related thiol isomerases ERp5 and ERp57, albeit to a lesser degree than PDI. Conclusions PDI activity is inhibited by red wine and grape juice, identifying a potentially novel mechanism underlying the cardiovascular benefits attributed to wine consumption. PMID:26585763

Crystal Structure of Escherichia coli L-Arabinose Isomerase (ECAI), The Putative Target of Biological Tagatose Production

Energy Technology Data Exchange (ETDEWEB)

Manjasetty,B.; Chance, M.

2006-01-01

Escherichia coli L-arabinose isomerase (ECAI; EC 5.3.1.4) catalyzes the isomerization of L-arabinose to L-ribulose in vivo. This enzyme is also of commercial interest as it catalyzes the conversion of D-galactose to D-tagatose in vitro. The crystal structure of ECAI was solved and refined at 2.6 Angstroms resolution. The subunit structure of ECAI is organized into three domains: an N-terminal, a central and a C-terminal domain. It forms a crystallographic trimeric architecture in the asymmetric unit. Packing within the crystal suggests the idea that ECAI can form a hexameric assembly. Previous electron microscopic and biochemical studies supports that ECAI is hexameric in solution. A comparison with other known structures reveals that ECAI adopts a protein fold most similar to E. coli fucose isomerase (ECFI) despite very low sequence identity 9.7%. The structural similarity between ECAI and ECFI with regard to number of domains, overall fold, biological assembly, and active site architecture strongly suggests that the enzymes have functional similarities. Further, the crystal structure of ECAI forms a basis for identifying molecular determinants responsible for isomerization of arabinose to ribulose in vivo and galactose to tagatose in vitro.

Domain architecture of protein-disulfide isomerase facilitates its dual role as an oxidase and an isomerase in Ero1p-mediated disulfide formation

DEFF Research Database (Denmark)

Kulp, M. S.; Frickel, E. M.; Ellgaard, Lars

2006-01-01

reduction/rearrangement of non-native disulfides is poorly understood. We analyzed the role of individual PDI domains in disulfide bond formation in a reaction driven by their natural oxidant, Ero1p. We found that Ero1p oxidizes the isolated PDI catalytic thioredoxin domains, A and A' at the same rate......Native disulfide bond formation in eukaryotes is dependent on protein-disulfide isomerase (PDI) and its homologs, which contain varying combinations of catalytically active and inactive thioredoxin domains. However, the specific contribution of PDI to the formation of new disulfides versus...... catalytic (A) domain. The specific order of thioredoxin domains in PDI is important in establishing the asymmetry in the rate of oxidation of the two active sites thus allowing A and A', two thioredoxin domains that are similar in sequence and structure, to serve opposing functional roles as a disulfide...

Overexpression, purification, crystallization and preliminary diffraction studies of the Protaminobacter rubrum sucrose isomerase SmuA

International Nuclear Information System (INIS)

Ravaud, Stéphanie; Watzlawick, Hildegard; Haser, Richard; Mattes, Ralf; Aghajari, Nushin

2005-01-01

The P. rubrum sucrose isomerase SmuA, a key enzyme in the industrial production of isomaltulose, was crystallized and diffraction data were collected to 1.95 Å resolution. Palatinose (isomaltulose, α-d-glucosylpyranosyl-1,6-d-fructofuranose), a nutritional and acariogenic reducing sugar, is industrially obtained from sucrose by using immobilized cells of Protaminobacter rubrum that produce the sucrose isomerase SmuA. The isomerization of sucrose catalyzed by this enzyme also results in the formation of trehalulose (α-d-glucosylpyranosyl-1,1-d-fructofuranose) in smaller amounts and glucose, fructose and eventually isomaltose as by-products, which lower the yield of the reaction and complicate the recovery of palatinose. The determination of the three-dimensional structure of SmuA will provide a basis for rational protein-engineering studies in order to optimize the industrial production of palatinose. A recombinant form of the 67.3 kDa SmuA enzyme has been crystallized in the native state by the vapour-diffusion method. Crystals belong to the orthorhombic space group P2 1 2 1 2 1 , with unit-cell parameters a = 61.6, b = 81.4, c = 135.6 Å, and diffract to 1.95 Å resolution on a synchrotron-radiation source

Characterization of an L-arabinose isomerase from Bacillus thermoglucosidasius for D-tagatose production.

Science.gov (United States)

Seo, Myung-Ji

2013-01-01

L-Arabinose isomerase from Bacillus thermoglucosidasius KCTC 1828 (BTAI) was expressed in Escherichia coli. The optimal temperature and pH for the activity of the purified BTAI were 40 °C and pH 7.0. The Mn(2+) ion was an activator of BTAI activity. The kinetic parameters of BTAI for D-galactose were a K(m) of 175 mM and a k(cat)/K(m) of 2.8 mM(-1)min(-1). The conversion ratio by BTAI to D-tagatose reached 45.6% at 40 °C.

Protein Disulfide Isomerase and Host-Pathogen Interaction

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Beatriz S. Stolf

2011-01-01

Full Text Available Reactive oxygen species (ROS production by immunological cells is known to cause damage to pathogens. Increasing evidence accumulated in the last decade has shown, however, that ROS (and redox signals functionally regulate different cellular pathways in the host-pathogen interaction. These especially affect (i pathogen entry through protein redox switches and redox modification (i.e., intra- and interdisulfide and cysteine oxidation and (ii phagocytic ROS production via Nox family NADPH oxidase enzyme and the control of phagolysosome function with key implications for antigen processing. The protein disulfide isomerase (PDI family of redox chaperones is closely involved in both processes and is also implicated in protein unfolding and trafficking across the endoplasmic reticulum (ER and towards the cytosol, a thiol-based redox locus for antigen processing. Here, we summarise examples of the cellular association of host PDI with different pathogens and explore the possible roles of pathogen PDIs in infection. A better understanding of these complex regulatory steps will provide insightful information on the redox role and coevolutional biological process, and assist the development of more specific therapeutic strategies in pathogen-mediated infections.

ORF Alignment: NC_000962 [GENIUS II[Archive

Lifescience Database Archive (English)

Full Text Available NC_000962 gi|57116993 >1uslC 1 158 13 170 3e-65 ... pdb|2BET|E Chain E, Structure Of Mycobacterium Tuberculosi...-D- ... Erythronate. pdb|2BET|D Chain D, Structure Of ... Mycobacterium Tuberculosis Ribose-5-...ronate. ... pdb|2BET|C Chain C, Structure Of Mycobacterium ... Tuberculosis Ribose-5-Phosphate...B, Structure Of Mycobacterium ... Tuberculosis Ribose-5-Phosphate Isomeras...ure Of Mycobacterium ... Tuberculosis Ribose-5-Phosphate Isomerase, Rpib, ... Rv2465c, In Comp

ORF Alignment: NC_002945 [GENIUS II[Archive

Lifescience Database Archive (English)

Full Text Available NC_002945 gi|31793646 >1uslC 1 158 13 170 3e-65 ... pdb|2BET|E Chain E, Structure Of Mycobacterium Tuberculosi...-D- ... Erythronate. pdb|2BET|D Chain D, Structure Of ... Mycobacterium Tuberculosis Ribose-5-...ronate. ... pdb|2BET|C Chain C, Structure Of Mycobacterium ... Tuberculosis Ribose-5-Phosphate...B, Structure Of Mycobacterium ... Tuberculosis Ribose-5-Phosphate Isomeras...ure Of Mycobacterium ... Tuberculosis Ribose-5-Phosphate Isomerase, Rpib, ... Rv2465c, In Comp

Enhanced pest resistance and increased phenolic production in maize callus transgenically expressing a maize chalcone isomerase -3 like gene

Science.gov (United States)

Significant losses in maize production are due to damage by insects and ear rot fungi. A gene designated as chalcone-isomerase-like, located in a quantitative trait locus for resistance to Fusarium ear rot fungi, was cloned from a Fusarium ear rot resistant inbred and transgenically expressed in mai...

Coexpression of β-D-galactosidase and L-arabinose isomerase in the production of D-tagatose: a functional sweetener.

Science.gov (United States)

Zhan, Yijing; Xu, Zheng; Li, Sha; Liu, Xiaoliu; Xu, Lu; Feng, Xiaohai; Xu, Hong

2014-03-19

The functional sweetener, d-tagatose, is commonly transformed from galactose by l-arabinose isomerase. To make use of a much cheaper starting material, lactose, hydrolization, and isomerization are required to take place collaboratively. Therefore, a single-step method involving β-d-galactosidase was explored for d-tagatose production. The two vital genes, β-d-galactosidase gene (lacZ) and l-arabinose isomerase mutant gene (araA') were extracted separately from Escherichia coli strains and incorporated into E. coli simultaneously. This gave us E. coli-ZY, a recombinant producing strain capable of coexpressing the two key enzymes. The resulted cells exhibited maximum d-tagatose producing activity at 34 °C and pH 6.5 and in the presence of borate, 10 mM Fe(2+), and 1 mM Mn(2+). Further monitoring showed that the recombinant cells could hydrolyze more than 95% lactose and convert 43% d-galactose into d-tagatose. This research has verified the feasibility of single-step d-tagatose fermentation, thereby laying down the foundation for industrial usage of lactose.

L-Rhamnose isomerase and its use for biotechnological production of rare sugars.

Science.gov (United States)

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

2016-04-01

L-Rhamnose isomerase (L-RI, EC 5.3.1.14), catalyzing the isomerization between L-rhamnose and L-rhamnulose, plays an important role in microbial L-rhamnose metabolism and thus occurs in a wide range of microorganisms. It attracts more and more attention because of its broad substrate specificity and its great potential in enzymatic production of various rare sugars. In this article, the enzymatic properties of various reported L-RIs were compared in detail, and their applications in the production of L-rhamnulose and various rare sugars including D-allose, D-gulose, L-lyxose, L-mannose, L-talose, and L-galactose were also reviewed.

Molecular Characterization and Analysis of a Novel Protein Disulfide Isomerase-Like Protein of Eimeria tenella

OpenAIRE

Han, Hongyu; Dong, Hui; Zhu, Shunhai; Zhao, Qiping; Jiang, Lianlian; Wang, Yange; Li, Liujia; Wu, Youlin; Huang, Bing

2014-01-01

Protein disulfide isomerase (PDI) and PDI-like proteins are members of the thioredoxin superfamily. They contain thioredoxin-like domains and catalyze the physiological oxidation, reduction and isomerization of protein disulfide bonds, which are involved in cell function and development in prokaryotes and eukaryotes. In this study, EtPDIL, a novel PDI-like gene of Eimeria tenella, was cloned using rapid amplification of cDNA ends (RACE) according to the expressed sequence tag (EST). The EtPDI...

Thermoinactivation Mechanism of Glucose Isomerase

Science.gov (United States)

Lim, Leng Hong; Saville, Bradley A.

In this article, the mechanisms of thermoinactivation of glucose isomerase (GI) from Streptomyces rubiginosus (in soluble and immobilized forms) were investigated, particularly the contributions of thiol oxidation of the enzyme's cysteine residue and a "Maillard-like" reaction between the enzyme and sugars in high fructose corn syrup (HFCS). Soluble GI (SGI) was successfully immobilized on silica gel (13.5 μm particle size), with an activity yield between 20 and 40%. The immobilized GI (IGI) has high enzyme retention on the support during the glucose isomerization process. In batch reactors, SGI (half-life =145 h) was more stable than IGI (half-life=27 h) at 60°C in HFCS, whereas at 80°C, IGI (half-life=12 h) was more stable than SGI (half-life=5.2 h). IGI was subject to thiol oxidation at 60°C, which contributed to the enzyme's deactivation. IGI was subject to thiol oxidation at 80°C, but this did not contribute to the deactivation of the enzyme. SGI did not undergo thiol oxidation at 60°C, but at 80°C SGI underwent severe precipitation and thiol oxidation, which caused the enzyme to deactivate. Experimental results show that immobilization suppresses the destablizing effect of thiol oxidation on GI. A "Maillard-like" reaction between SGI and the sugars also caused SGI thermoinactivation at 60, 70, and 80°C, but had minimal effect on IGI. At 60 and 80°C, IGI had higher thermostability in continuous reactors than in batch reactors, possibily because of reduced contact with deleterious compounds in HFCS.

Characterization of the triple-component linoleic acid isomerase in Lactobacillus plantarum ZS2058 by genetic manipulation.

Science.gov (United States)

Yang, B; Qi, H; Gu, Z; Zhang, H; Chen, W; Chen, H; Chen, Y Q

2017-11-01

To assess the mechanism for conjugated linoleic acid (CLA) production in Lactobacillus plantarum ZS2058. CLA has attracted great interests for decades due to its health-associated benefits including anticancer, anti-atherogenic, anti-obesity and modulation of the immune system. A number of microbial CLA producers were widely reported including lactic acid bacteria. Lactobacillus plantarum ZS2058, an isolate from Chinese traditional fermented food, could convert LA to CLA with various intermediates. To characterize the genetic determinants for generating CLA, a cre-lox-based system was utilized to delete the genes encoding myosin cross-reactive antigen (MCRA), short-chain dehydrogenase/oxidoreductase (DH) and acetoacetate decarboxylase (DC) in Lact. plantarum ZS2058, respectively. Neither intermediate was detected in the corresponding gene deletion mutant. Meanwhile all those mutants could recover the ability to convert linoleic acid to CLA when the corresponding gene was completed. The results indicated that CLA production was a multiple-step reaction catalysed by triple-component linoleate isomerase system encoded by mcra, dh and dc. Multicomponent linoleic acid isomerase provided important results for illustration unique mechanism for CLA production in Lact. plantarum ZS2058. Lactobacilli with CLA production ability offer novel opportunities for functional food development. © 2017 The Society for Applied Microbiology.

Transmutation of human glutathione transferase A2-2 with peroxidase activity into an efficient steroid isomerase.

Science.gov (United States)

Pettersson, Par L; Johansson, Ann-Sofie; Mannervik, Bengt

2002-08-16

A major goal in protein engineering is the tailor-making of enzymes for specified chemical reactions. Successful attempts have frequently been based on directed molecular evolution involving libraries of random mutants in which variants with desired properties were identified. For the engineering of enzymes with novel functions, it would be of great value if the necessary changes of the active site could be predicted and implemented. Such attempts based on the comparison of similar structures with different substrate selectivities have previously met with limited success. However, the present work shows that the knowledge-based redesign restricted to substrate-binding residues in human glutathione transferase A2-2 can introduce high steroid double-bond isomerase activity into the enzyme originally characterized by glutathione peroxidase activity. Both the catalytic center activity (k(cat)) and catalytic efficiency (k(cat)/K(m)) match the values of the naturally evolved glutathione transferase A3-3, the most active steroid isomerase known in human tissues. The substrate selectivity of the mutated glutathione transferase was changed 7000-fold by five point mutations. This example demonstrates the functional plasticity of the glutathione transferase scaffold as well as the potential of rational active-site directed mutagenesis as a complement to DNA shuffling and other stochastic methods for the redesign of proteins with novel functions.

Pairwise contact energy statistical potentials can help to find probability of point mutations.

Science.gov (United States)

Saravanan, K M; Suvaithenamudhan, S; Parthasarathy, S; Selvaraj, S

2017-01-01

To adopt a particular fold, a protein requires several interactions between its amino acid residues. The energetic contribution of these residue-residue interactions can be approximated by extracting statistical potentials from known high resolution structures. Several methods based on statistical potentials extracted from unrelated proteins are found to make a better prediction of probability of point mutations. We postulate that the statistical potentials extracted from known structures of similar folds with varying sequence identity can be a powerful tool to examine probability of point mutation. By keeping this in mind, we have derived pairwise residue and atomic contact energy potentials for the different functional families that adopt the (α/β) 8 TIM-Barrel fold. We carried out computational point mutations at various conserved residue positions in yeast Triose phosphate isomerase enzyme for which experimental results are already reported. We have also performed molecular dynamics simulations on a subset of point mutants to make a comparative study. The difference in pairwise residue and atomic contact energy of wildtype and various point mutations reveals probability of mutations at a particular position. Interestingly, we found that our computational prediction agrees with the experimental studies of Silverman et al. (Proc Natl Acad Sci 2001;98:3092-3097) and perform better prediction than i Mutant and Cologne University Protein Stability Analysis Tool. The present work thus suggests deriving pairwise contact energy potentials and molecular dynamics simulations of functionally important folds could help us to predict probability of point mutations which may ultimately reduce the time and cost of mutation experiments. Proteins 2016; 85:54-64. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Prevalence of Giardia and Cryptosporidium species in dog park attending dogs compared to non-dog park attending dogs in one region of Colorado.

Science.gov (United States)

Wang, Andrea; Ruch-Gallie, Rebecca; Scorza, Valeria; Lin, Philip; Lappin, Michael R

2012-03-23

Dog parks are very popular in urban areas, but there are no current studies attempting to correlate visits to dog parks and risk of colonization by enteric parasites. The purpose of this study was to determine whether dog park visitation is associated with an increased prevalence of enteric parasites or an increase in prevalence of gastrointestinal signs in dogs in northern Colorado. Feces from dogs owned by veterinary students or Veterinary Teaching Hospital staff members were submitted with a completed survey form detailing dog park attendance rates, fecal character scores, and other clinical information. Feces were examined microscopically for parasites after sugar centrifugation, for Giardia spp. cysts and Cryptosporidium spp. oocysts by a commercially available immunofluorescence assay (FA) and the FA positive samples were genotyped after PCR amplification. The Giardia assemblages were determined using the glutamate dehydrogenase (GDH) β-giardin and triose phosphate isomerase (TPI) genes and the Cryptosporidium species were determined using the heat shock protein-70 gene. A total of 129 fecal samples were assayed; 66 were from dog park attending dogs and 63 were from non-dog park-attending dogs. The overall parasite prevalence rate was 7.0% (9 of 129 samples). Dog park attending dogs were more likely to be positive for Giardia or Cryptosporidium than non-dog park-attending dogs (p=0.0279), but there was no association of gastrointestinal signs with dog park attendance or with fecal flotation or FA results. The five Giardia isolates were assemblage C and/or D and the one Cryptosporidium isolate was Ctenocephalides canis. Copyright © 2011 Elsevier B.V. All rights reserved.

Comparison of the xylose reductase-xylitol dehydrogenase and the xylose isomerase pathways for xylose fermentation by recombinant Saccharomyces cerevisiae

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Hahn-Hägerdal Bärbel

2007-02-01

Full Text Available Abstract Background Two heterologous pathways have been used to construct recombinant xylose-fermenting Saccharomyces cerevisiae strains: i the xylose reductase (XR and xylitol dehydrogenase (XDH pathway and ii the xylose isomerase (XI pathway. In the present study, the Pichia stipitis XR-XDH pathway and the Piromyces XI pathway were compared in an isogenic strain background, using a laboratory host strain with genetic modifications known to improve xylose fermentation (overexpressed xylulokinase, overexpressed non-oxidative pentose phosphate pathway and deletion of the aldose reductase gene GRE3. The two isogenic strains and the industrial xylose-fermenting strain TMB 3400 were studied regarding their xylose fermentation capacity in defined mineral medium and in undetoxified lignocellulosic hydrolysate. Results In defined mineral medium, the xylose consumption rate, the specific ethanol productivity, and the final ethanol concentration were significantly higher in the XR- and XDH-carrying strain, whereas the highest ethanol yield was achieved with the strain carrying XI. While the laboratory strains only fermented a minor fraction of glucose in the undetoxified lignocellulose hydrolysate, the industrial strain TMB 3400 fermented nearly all the sugar available. Xylitol was formed by the XR-XDH-carrying strains only in mineral medium, whereas in lignocellulose hydrolysate no xylitol formation was detected. Conclusion Despite by-product formation, the XR-XDH xylose utilization pathway resulted in faster ethanol production than using the best presently reported XI pathway in the strain background investigated. The need for robust industrial yeast strains for fermentation of undetoxified spruce hydrolysates was also confirmed.

Regulation of plant cytosolic glyceraldehyde 3-phosphate dehydrogenase isoforms by thiol modifications.

Science.gov (United States)

Holtgrefe, Simone; Gohlke, Jochen; Starmann, Julia; Druce, Samantha; Klocke, Susanne; Altmann, Bianca; Wojtera, Joanna; Lindermayr, Christian; Scheibe, Renate

2008-06-01

Cytosolic NAD-dependent glyceraldehyde 3-P dehydrogenase (GAPDH; GapC; EC 1.2.1.12) catalyzes the oxidation of triose phosphates during glycolysis in all organisms, but additional functions of the protein has been put forward. Because of its reactive cysteine residue in the active site, it is susceptible to protein modification and oxidation. The addition of GSSG, and much more efficiently of S-nitrosoglutathione, was shown to inactivate the enzymes from Arabidopsis thaliana (isoforms GapC1 and 2), spinach, yeast and rabbit muscle. Inactivation was fully or at least partially reversible upon addition of DTT. The incorporation of glutathione upon formation of a mixed disulfide could be shown using biotinylated glutathione ethyl ester. Furthermore, using the biotin-switch assay, nitrosylated thiol groups could be shown to occur after treatment with nitric oxide donors. Using mass spectrometry and mutant proteins with one cysteine lacking, both cysteines (Cys-155 and Cys-159) were found to occur as glutathionylated and as nitrosylated forms. In preliminary experiments, it was shown that both GapC1 and GapC2 can bind to a partial gene sequence of the NADP-dependent malate dehydrogenase (EC 1.2.1.37; At5g58330). Transiently expressed GapC-green fluorescent protein fusion proteins were localized to the nucleus in A. thaliana protoplasts. As nuclear localization and DNA binding of GAPDH had been shown in numerous systems to occur upon stress, we assume that such mechanism might be part of the signaling pathway to induce increased malate-valve capacity and possibly other protective systems upon overreduction and initial formation of reactive oxygen and nitrogen species as well as to decrease and protect metabolism at the same time by modification of essential cysteine residues.

Formation of xylitol and xylitol-5-phosphate and its impact on growth of d-xylose-utilizing Corynebacterium glutamicum strains.

Science.gov (United States)

Radek, Andreas; Müller, Moritz-Fabian; Gätgens, Jochem; Eggeling, Lothar; Krumbach, Karin; Marienhagen, Jan; Noack, Stephan

2016-08-10

Wild-type Corynebacterium glutamicum has no endogenous metabolic activity for utilizing the lignocellulosic pentose d-xylose for cell growth. Therefore, two different engineering approaches have been pursued resulting in platform strains harbouring a functional version of either the Isomerase (ISO) or the Weimberg (WMB) pathway for d-xylose assimilation. In a previous study we found for C. glutamicum WMB by-product formation of xylitol during growth on d-xylose and speculated that the observed lower growth rates are due to the growth inhibiting effect of this compound. Based on a detailed phenotyping of the ISO, WMB and the wild-type strain of C. glutamicum, we here show that this organism has a natural capability to synthesize xylitol from d-xylose under aerobic cultivation conditions. We furthermore observed the intracellular accumulation of xylitol-5-phosphate as a result of the intracellular phosphorylation of xylitol, which was particularly pronounced in the C. glutamicum ISO strain. Interestingly, low amounts of supplemented xylitol strongly inhibit growth of this strain on d-xylose, d-glucose and d-arabitol. These findings demonstrate that xylitol is a suitable substrate of the endogenous xylulokinase (XK, encoded by xylB) and its overexpression in the ISO strain leads to a significant phosphorylation of xylitol in C. glutamicum. Therefore, in order to circumvent cytotoxicity by xylitol-5-phosphate, the WMB pathway represents an interesting alternative route for engineering C. glutamicum towards efficient d-xylose utilization. Copyright © 2016 Elsevier B.V. All rights reserved.

Helicobacter pylori Peptidyl Prolyl Isomerase Expression Is Associated with the Severity of Gastritis.

Science.gov (United States)

Oghalaie, Akbar; Saberi, Samaneh; Esmaeili, Maryam; Ebrahimzadeh, Fatemeh; Barkhordari, Farzaneh; Ghamarian, Abdolreza; Tashakoripoor, Mohammad; Abdirad, Afshin; Eshagh Hosseini, Mahmoud; Khalaj, Vahid; Mohammadi, Marjan

2016-12-01

Helicobacter pylori secretory peptidyl prolyl isomerase, HP0175, is progressively identified as a pro-inflammatory and pro-carcinogenic protein, which serves to link H. pylori infection to its more severe clinical outcomes. Here, we have analyzed host HP0175-specific antibody responses in relation to the severity of gastritis. The HP0175 gene fragment was PCR-amplified, cloned, expressed and purified by Ni-NTA affinity chromatography. Serum antigen-specific antibody responses of non-ulcer dyspeptic patients (N = 176) against recombinant HP0175 were detected by western blotting. The infection status of these subjects was determined by rapid urease test, culture, histology, and serology. The grade of inflammation and stage of atrophy were scored blindly according to the OLGA staging system. The recombinant HP0175 (rHP0175) was expressed as a ~35 kDa protein and its identity was confirmed by western blotting using anti-6X His tag antibody and pooled H. pylori-positive sera. Serum IgG antibodies against rHP0175 segregated our patients into two similar-sized groups of sero-positives (90/176, 51.1 %) and sero-negatives (86/176, 48.9 %). The former presented with higher grades of gastric inflammation (OR = 4.4, 95 % CI = 1.9-9.9, P = 0.001) and stages of gastric atrophy (OR = 18.3, 95 %CI = 1.4-246.6, P = 0.028). Our findings lend further support to the pro-inflammatory nature of H. pylori peptidyl prolyl isomerase (HP0175) and recommends this antigen as a non-invasive serum biomarker of the severity of H. pylori-associated gastritis.

Kinetic analysis of the mechanism and specificity of protein-disulfide isomerase using fluorescence-quenched peptides

DEFF Research Database (Denmark)

Westphal, V; Spetzler, J C; Meldal, M

1998-01-01

Protein-disulfide isomerase (PDI) is an abundant folding catalyst in the endoplasmic reticulum of eukaryotic cells. PDI introduces disulfide bonds into newly synthesized proteins and catalyzes disulfide bond isomerizations. We have synthesized a library of disulfide-linked fluorescence......-quenched peptides, individually linked to resin beads, for two purposes: 1) to probe PDI specificity, and 2) to identify simple, sensitive peptide substrates of PDI. Using this library, beads that became rapidly fluorescent by reduction by human PDI were selected. Amino acid sequencing of the bead-linked peptides...

Glucose isomerization in simulated moving bed reactor by Glucose isomerase

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Eduardo Alberto Borges da Silva

2006-05-01

Full Text Available Studies were carried out on the production of high-fructose syrup by Simulated Moving Bed (SMB technology. A mathematical model and numerical methodology were used to predict the behavior and performance of the simulated moving bed reactors and to verify some important aspects for application of this technology in the isomerization process. The developed algorithm used the strategy that considered equivalences between simulated moving bed reactors and true moving bed reactors. The kinetic parameters of the enzymatic reaction were obtained experimentally using discontinuous reactors by the Lineweaver-Burk technique. Mass transfer effects in the reaction conversion using the immobilized enzyme glucose isomerase were investigated. In the SMB reactive system, the operational variable flow rate of feed stream was evaluated to determine its influence on system performance. Results showed that there were some flow rate values at which greater purities could be obtained.Neste trabalho a tecnologia de Leito Móvel Simulado (LMS reativo é aplicada no processo de isomerização da glicose visando à produção de xarope concentrado de frutose. É apresentada a modelagem matemática e uma metodologia numérica para predizer o comportamento e o desempenho de unidades reativas de leito móvel simulado para verificar alguns aspectos importantes para o emprego desta tecnologia no processo de isomerização. O algoritmo desenvolvido utiliza a abordagem que considera as equivalências entre as unidades reativas de leito móvel simulado e leito móvel verdadeiro. Parâmetros cinéticos da reação enzimática são obtidos experimentalmente usando reatores em batelada pela técnica Lineweaver-Burk. Efeitos da transferência de massa na conversão de reação usando a enzima imobilizada glicose isomerase são verificados. No sistema reativo de LMS, a variável operacional vazão da corrente de alimentação é avaliada para conhecer o efeito de sua influência no

Mechanisms of Neuroprotection by Protein Disulphide Isomerase in Amyotrophic Lateral Sclerosis

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Adam K. Walker

2011-01-01

Full Text Available Amyotrophic lateral sclerosis (ALS is a devastating neurodegenerative disease characterised by the progressive loss of motor neurons, leading to paralysis and death within several years of onset. Although protein misfolding is a key feature of ALS, the upstream triggers of disease remain elusive. Recently, endoplasmic reticulum (ER stress was identified as an early and central feature in ALS disease models as well as in human patient tissues, indicating that ER stress could be an important process in disease pathogenesis. One important chaperone induced by ER stress is protein disulphide isomerase (PDI, which is both upregulated and posttranslationally inhibited by S-nitrosylation in ALS. In this paper, we present evidence from studies of genetics, model organisms, and patient tissues which indicate an active role for PDI and ER stress in ALS disease processes.

Phosphorus release from phosphate rock and iron phosphate by low-molecular-weight organic acids.

Science.gov (United States)

Xu, Ren-kou; Zhu, Yong-guan; Chittleborough, David

2004-01-01

Low-molecular-weight(LMW) organic acids widely exist in soils, particularly in the rhizosphere. A series of batch experiments were carried out to investigate the phosphorus release from rock phosphate and iron phosphate by low-molecular-weight organic acids. Results showed that citric acid had the highest capacity to solubilize P from both rock and iron phosphate. P solubilization from rock phosphate and iron phosphate resulted in net proton consumption. P release from rock phosphate was positively correlated with the pKa values. P release from iron phosphate was positively correlated with Fe-organic acid stability constants except for aromatic acids, but was notcorrelated with pKa. Increase in the concentrations of organic acids enhanced P solubilization from both rock and iron phosphate almost linearly. Addition of phenolic compounds further increased the P release from iron phosphate. Initial solution pH had much more substantial effect on P release from rock phosphate than from iron phosphate.

Identification and characterization of a novel L-arabinose isomerase from Anoxybacillus flavithermus useful in D-tagatose production.

Science.gov (United States)

Li, Yanjun; Zhu, Yueming; Liu, Anjun; Sun, Yuanxia

2011-05-01

D-Tagatose is a highly functional rare ketohexose and many attempts have been made to convert D-galactose into the valuable D-tagatose using L-arabinose isomerase (L-AI). In this study, a thermophilic strain possessing L-AI gene was isolated from hot spring sludge and identified as Anoxybacillus flavithermus based on its physio-biochemical characterization and phylogenetic analysis of its 16s rRNA gene. Furthermore, the gene encoding L-AI from A. flavithermus (AFAI) was cloned and expressed at a high level in E. coli BL21(DE3). L-AI had a molecular weight of 55,876 Da, an optimum pH of 10.5 and temperature of 95°C. The results showed that the conversion equilibrium shifted to more D-tagatose from D-galactose by raising the reaction temperatures and adding borate. A 60% conversion of D-galactose to D-tagatose was observed at an isomerization temperature of 95°C with borate. The catalytic efficiency (k (cat) /K (m)) for D-galactose with borate was 9.47 mM(-1) min(-1), twice as much as that without borate. Our results indicate that AFAI is a novel hyperthermophilic and alkaliphilic isomerase with a higher catalytic efficiency for D-galactose, suggesting its great potential for producing D-tagatose.

Human cyclophilin B: A second cyclophilin gene encodes a peptidyl-prolyl isomerase with a signal sequence

International Nuclear Information System (INIS)

Price, E.R.; Zydowsky, L.D.; Jin, Mingjie; Baker, C.H.; McKeon, F.D.; Walsh, C.T.

1991-01-01

The authors report the cloning and characterization of a cDNA encoding a second human cyclosporin A-binding protein (hCyPB). Homology analyses reveal that hCyPB is a member of the cyclophilin B (CyPB) family, which includes yeast CyPB, Drosophila nina A, and rat cyclophilin-like protein. This family is distinguished from the cyclophilin A (CyPA) family by the presence of endoplasmic reticulum (ER)-directed signal sequences. hCyPB has a hydrophobic leader sequence not found in hCyPA, and its first 25 amino acids are removed upon expression in Escherichia coli. Moreover, they show that hCyPB is a peptidyl-prolyl cis-trans isomerase which can be inhibited by cyclosporin A. These observations suggest that other members of the CyPB family will have similar enzymatic properties. Sequence comparisons of the CyPB proteins show a central, 165-amino acid peptidyl-prolyl isomerase and cyclosprorin A-binding domain, flanked by variable N-terminal and C-terminal domains. These two variable regions may impart compartmental specificity and regulation to this family of cyclophilin proteins containing the conserved core domain. Northern blot analyses show that hCyPB mRNA is expressed in the Jurkat T-cell line, consistent with its possible target role in cyclosporin A-mediated immunosuppression

Xylose utilization in recombinant zymomonas

Science.gov (United States)

Caimi, Perry G; McCole, Laura; Tao, Luan; Tomb, Jean-Francois; Viitanen, Paul V

2014-03-25

Xylose-utilizing Zymomonas strains studied were found to accumulate ribulose when grown in xylose-containing media. Engineering these strains to increase ribose-5-phosphate isomerase activity led to reduced ribulose accumulation, improved growth, improved xylose utilization, and increased ethanol production.

Rapid expansion of the protein disulfide isomerase gene family facilitates the folding of venom peptides

DEFF Research Database (Denmark)

Safavi-Hemami, Helena; Li, Qing; Jackson, Ronneshia L.

2016-01-01

Formation of correct disulfide bonds in the endoplasmic reticulum is a crucial step for folding proteins destined for secretion. Protein disulfide isomerases (PDIs) play a central role in this process. We report a previously unidentified, hypervariable family of PDIs that represents the most...... diverse gene family of oxidoreductases described in a single genus to date. These enzymes are highly expressed specifically in the venom glands of predatory cone snails, animals that synthesize a remarkably diverse set of cysteine-rich peptide toxins (conotoxins). Enzymes in this PDI family, termed...

The Expression of Millettia pinnata Chalcone Isomerase in Saccharomyces cerevisiae Salt-Sensitive Mutants Enhances Salt-Tolerance

OpenAIRE

Wang, Hui; Hu, Tangjin; Huang, Jianzi; Lu, Xiang; Huang, Baiqu; Zheng, Yizhi

2013-01-01

The present study demonstrates a new Millettia pinnata chalcone isomerase (MpCHI) whose transcription level in leaf was confirmed to be enhanced after being treated by seawater or NaCl (500 mM) via transcriptome sequencing and Real-Time Quantitative Reverse Transcription PCR (QRT-PCR) analyses. Its full length cDNA (666 bp) was obtained by 3'-end and 5'-end Rapid Amplification of cDNA Ends (RACE). The analysis via NCBI BLAST indicates that both aminoacid sequence and nucleotide sequ...

Production of D-tagatose at high temperatures using immobilized Escherichia coli cells expressing L-arabinose isomerase from Thermotoga neapolitana.

Science.gov (United States)

Hong, Young-Ho; Lee, Dong-Woo; Lee, Sang-Jae; Choe, Eun-Ah; Kim, Seong-Bo; Lee, Yoon-Hee; Cheigh, Chan-Ick; Pyun, Yu-Ryang

2007-04-01

Escherichia coli cells expressing L-arabinose isomerase from Thermotoga neapolitana (TNAI) were immobilized in calcium alginate beads. The resulting cell reactor (2.4 U, t (1/2) = 43 days at 70 degrees C) in a continuous recycling mode at 70 degrees C produced 49 and 38 g D-tagatose/l from 180 and 90 g D-galactose/l, respectively, within 12 h.

Removal of phosphate from solution by adsorption and precipitation of calcium phosphate onto monohydrocalcite.

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Yagi, Shintaro; Fukushi, Keisuke

2012-10-15

The sorption behavior and mechanism of phosphate on monohydrocalcite (CaCO(3)·H(2)O: MHC) were examined using batch sorption experiments as a function of phosphate concentrations, ionic strengths, temperatures, and reaction times. The mode of PO(4) sorption is divisible into three processes depending on the phosphate loading. At low phosphate concentrations, phosphate is removed by coprecipitation of phosphate during the transformation of MHC to calcite. The sorption mode at the low-to-moderate phosphate concentrations is most likely an adsorption process because the sorption isotherm at the conditions can be fitted reasonably with the Langmuir equation. The rapid sorption kinetics at the conditions is also consistent with the adsorption reaction. The adsorption of phosphate on MHC depends strongly on ionic strength, but slightly on temperature. The maximum adsorption capacities of MHC obtained from the regression of the experimental data to the Langmuir equation are higher than those reported for stable calcium carbonate (calcite or aragonite) in any conditions. At high phosphate concentrations, the amount of sorption deviates from the Langmuir isotherm, which can fit the low-to-moderate phosphate concentrations. Speciation-saturation analyses of the reacted solutions at the conditions indicated that the solution compositions which deviate from the Langmuir equation are supersaturated with respect to a certain calcium phosphate. The obtained calcium phosphate is most likely amorphous calcium phosphate (Ca(3)(PO(4))(2)·xH(2)O). The formation of the calcium phosphate depends strongly on ionic strength, temperature, and reaction times. The solubility of MHC is higher than calcite and aragonite because of its metastability. Therefore, the higher solubility of MHC facilitates the formation of the calcium phosphates more than with calcite and aragonite. Copyright © 2012 Elsevier Inc. All rights reserved.

From dirt to industrial applications: Pseudomonas putida as a Synthetic Biology chassis for hosting harsh biochemical reactions.

Science.gov (United States)

Nikel, Pablo I; Chavarría, Max; Danchin, Antoine; de Lorenzo, Víctor

2016-10-01

The soil bacterium Pseudomonas putida is endowed with a central carbon metabolic network capable of fulfilling high demands of reducing power. This situation arises from a unique metabolic architecture that encompasses the partial recycling of triose phosphates to hexose phosphates-the so-called EDEMP cycle. In this article, the value of P. putida as a bacterial chassis of choice for contemporary, industrially-oriented metabolic engineering is addressed. The biochemical properties that make this bacterium adequate for hosting biotransformations involving redox reactions as well as toxic compounds and intermediates are discussed. Finally, novel developments and open questions in the continuous quest for an optimal microbial cell factory are presented at the light of current and future needs in the area of biocatalysis. Copyright © 2016 Elsevier Ltd. All rights reserved.

The first case of a complete deficiency of diphosphoglycerate mutase in human erythrocytes.

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Rosa, R; Prehu, M O; Beuzard, Y; Rosa, J

1978-11-01

An inherited and complete deficiency of diphosphoglycerate mutase was discovered in the erythrocytes of a 42-yr-old man of French origin whose blood hemoglobin concentration was 19.0 g/dl. Upon physical examination he was normal with the exception of a ruddy cyanosis. The morphology of his erythrocytes was also normal and there was no evidence of hemolysis. The erythrocyte 2,3-diphosphoglycerate level was below 3% of normal values and, as a consequence, the affinity of the cells for oxygen was increased. Diphosphoglycerate mutase activity was undetectable in erythrocytes as was that of diphosphoglycerate phosphatase. The activities of all the other erythrocyte enzymes that were tested were normal except for nomophosphoglycerate mutase which was diminished to 50% of the normal value. The levels of reduced glutathione, ATP, fructose 1,6-diphosphate, and of triose phosphates were elevated, whereas those of glucose 6-phosphate and fructose 6-phosphate were decreased. This report sheds new light on the role of diphosphoglycerate mutase in the metabolism of erythrocytes.

The human protein disulfide isomerase gene family

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Galligan James J

2012-07-01

Full Text Available Abstract Enzyme-mediated disulfide bond formation is a highly conserved process affecting over one-third of all eukaryotic proteins. The enzymes primarily responsible for facilitating thiol-disulfide exchange are members of an expanding family of proteins known as protein disulfide isomerases (PDIs. These proteins are part of a larger superfamily of proteins known as the thioredoxin protein family (TRX. As members of the PDI family of proteins, all proteins contain a TRX-like structural domain and are predominantly expressed in the endoplasmic reticulum. Subcellular localization and the presence of a TRX domain, however, comprise the short list of distinguishing features required for gene family classification. To date, the PDI gene family contains 21 members, varying in domain composition, molecular weight, tissue expression, and cellular processing. Given their vital role in protein-folding, loss of PDI activity has been associated with the pathogenesis of numerous disease states, most commonly related to the unfolded protein response (UPR. Over the past decade, UPR has become a very attractive therapeutic target for multiple pathologies including Alzheimer disease, Parkinson disease, alcoholic and non-alcoholic liver disease, and type-2 diabetes. Understanding the mechanisms of protein-folding, specifically thiol-disulfide exchange, may lead to development of a novel class of therapeutics that would help alleviate a wide range of diseases by targeting the UPR.

Phosphate Recovery From Sewage Sludge Containing Iron Phosphate

NARCIS (Netherlands)

Wilfert, P.K.

2018-01-01

The scope of this thesis was to lay the basis for a phosphate recovery technology that can be applied on sewage sludge containing iron phosphate. Such a technology should come with minimal changes to the existing sludge treatment configuration while keeping the use of chemicals or energy as small as

Effects of peptidyl-prolyl isomerase 1 depletion in animal models of prion diseases.

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Legname, Giuseppe; Virgilio, Tommaso; Bistaffa, Edoardo; De Luca, Chiara Maria Giulia; Catania, Marcella; Zago, Paola; Isopi, Elisa; Campagnani, Ilaria; Tagliavini, Fabrizio; Giaccone, Giorgio; Moda, Fabio

2018-04-20

Pin1 is a peptidyl-prolyl isomerase that induces the cis-trans conversion of specific Ser/Thr-Pro peptide bonds in phosphorylated proteins, leading to conformational changes through which Pin1 regulates protein stability and activity. Since down-regulation of Pin1 has been described in several neurodegenerative disorders, including Alzheimer's Disease (AD), Parkinson's Disease (PD) and Huntington's Disease (HD), we investigated its potential role in prion diseases. Animals generated on wild-type (Pin1 +/+ ), hemizygous (Pin1 +/- ) or knock-out (Pin1 -/- ) background for Pin1 were experimentally infected with RML prions. The study indicates that, neither the total depletion nor reduced levels of Pin1 significantly altered the clinical and neuropathological features of the disease.

A method for the production of D-tagatose using a recombinant Pichia pastoris strain secreting β-D-galactosidase from Arthrobacter chlorophenolicus and a recombinant L-arabinose isomerase from Arthrobacter sp. 22c

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Wanarska Marta

2012-08-01

Full Text Available Abstract Background D-Tagatose is a natural monosaccharide which can be used as a low-calorie sugar substitute in food, beverages and pharmaceutical products. It is also currently being tested as an anti-diabetic and obesity control drug. D-Tagatose is a rare sugar, but it can be manufactured by the chemical or enzymatic isomerization of D-galactose obtained by a β-D-galactosidase-catalyzed hydrolysis of milk sugar lactose and the separation of D-glucose and D-galactose. L-Arabinose isomerases catalyze in vitro the conversion of D-galactose to D-tagatose and are the most promising enzymes for the large-scale production of D-tagatose. Results In this study, the araA gene from psychrotolerant Antarctic bacterium Arthrobacter sp. 22c was isolated, cloned and expressed in Escherichia coli. The active form of recombinant Arthrobacter sp. 22c L-arabinose isomerase consists of six subunits with a combined molecular weight of approximately 335 kDa. The maximum activity of this enzyme towards D-galactose was determined as occurring at 52°C; however, it exhibited over 60% of maximum activity at 30°C. The recombinant Arthrobacter sp. 22c L-arabinose isomerase was optimally active at a broad pH range of 5 to 9. This enzyme is not dependent on divalent metal ions, since it was only marginally activated by Mg2+, Mn2+ or Ca2+ and slightly inhibited by Co2+ or Ni2+. The bioconversion yield of D-galactose to D-tagatose by the purified L-arabinose isomerase reached 30% after 36 h at 50°C. In this study, a recombinant Pichia pastoris yeast strain secreting β-D-galactosidase Arthrobacter chlorophenolicus was also constructed. During cultivation of this strain in a whey permeate, lactose was hydrolyzed and D-glucose was metabolized, whereas D-galactose was accumulated in the medium. Moreover, cultivation of the P. pastoris strain secreting β-D-galactosidase in a whey permeate supplemented with Arthrobacter sp. 22c L-arabinose isomerase resulted in a 90% yield

A method for the production of D-tagatose using a recombinant Pichia pastoris strain secreting β-D-galactosidase from Arthrobacter chlorophenolicus and a recombinant L-arabinose isomerase from Arthrobacter sp. 22c.

Science.gov (United States)

Wanarska, Marta; Kur, Józef

2012-08-23

D-Tagatose is a natural monosaccharide which can be used as a low-calorie sugar substitute in food, beverages and pharmaceutical products. It is also currently being tested as an anti-diabetic and obesity control drug. D-Tagatose is a rare sugar, but it can be manufactured by the chemical or enzymatic isomerization of D-galactose obtained by a β-D-galactosidase-catalyzed hydrolysis of milk sugar lactose and the separation of D-glucose and D-galactose. L-Arabinose isomerases catalyze in vitro the conversion of D-galactose to D-tagatose and are the most promising enzymes for the large-scale production of D-tagatose. In this study, the araA gene from psychrotolerant Antarctic bacterium Arthrobacter sp. 22c was isolated, cloned and expressed in Escherichia coli. The active form of recombinant Arthrobacter sp. 22c L-arabinose isomerase consists of six subunits with a combined molecular weight of approximately 335 kDa. The maximum activity of this enzyme towards D-galactose was determined as occurring at 52°C; however, it exhibited over 60% of maximum activity at 30°C. The recombinant Arthrobacter sp. 22c L-arabinose isomerase was optimally active at a broad pH range of 5 to 9. This enzyme is not dependent on divalent metal ions, since it was only marginally activated by Mg2+, Mn2+ or Ca2+ and slightly inhibited by Co2+ or Ni2+. The bioconversion yield of D-galactose to D-tagatose by the purified L-arabinose isomerase reached 30% after 36 h at 50°C. In this study, a recombinant Pichia pastoris yeast strain secreting β-D-galactosidase Arthrobacter chlorophenolicus was also constructed. During cultivation of this strain in a whey permeate, lactose was hydrolyzed and D-glucose was metabolized, whereas D-galactose was accumulated in the medium. Moreover, cultivation of the P. pastoris strain secreting β-D-galactosidase in a whey permeate supplemented with Arthrobacter sp. 22c L-arabinose isomerase resulted in a 90% yield of lactose hydrolysis, the complete utilization

Phosphate-a poison for humans?

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Komaba, Hirotaka; Fukagawa, Masafumi

2016-10-01

Maintenance of phosphate balance is essential for life, and mammals have developed a sophisticated system to regulate phosphate homeostasis over the course of evolution. However, due to the dependence of phosphate elimination on the kidney, humans with decreased kidney function are likely to be in a positive phosphate balance. Phosphate excess has been well recognized as a critical factor in the pathogenesis of mineral and bone disorders associated with chronic kidney disease, but recent investigations have also uncovered toxic effects of phosphate on the cardiovascular system and the aging process. Compelling evidence also suggests that increased fibroblastic growth factor 23 and parathyroid hormone levels in response to a positive phosphate balance contribute to adverse clinical outcomes. These insights support the current practice of managing serum phosphate in patients with advanced chronic kidney disease, although definitive evidence of these effects is lacking. Given the potential toxicity of excess phosphate, the general population may also be viewed as a target for phosphate management. However, the widespread implementation of dietary phosphate intervention in the general population may not be warranted due to the limited impact of increased phosphate intake on mineral metabolism and clinical outcomes. Nonetheless, the increasing incidence of kidney disease or injury in our aging society emphasizes the potential importance of this issue. Further work is needed to more completely characterize phosphate toxicity and to establish the optimal therapeutic strategy for managing phosphate in patients with chronic kidney disease and in the general population. Copyright © 2016 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.

Triphenyl phosphate allergy from spectacle frames

DEFF Research Database (Denmark)

Carlsen, L; Andersen, K E; Egsgaard, Helge

1986-01-01

A case of triphenyl phosphate allergy from spectacle frames is reported. Patch tests with analytical grade triphenyl phosphate, tri-m-cresyl phosphate, and tri-p-cresyl phosphate in the concentrations 5%, 0.5% and 0.05% pet. showed positive reactions to 0.05% triphenyl phosphate and 0.5% tri......-m-cresyl phosphate, but no reaction to tri-p-cresyl phosphate. Gas chromatography of the tricresyl phosphate 5% pet. patch test material supplied from Trolab showed that it contained a mixture of a wide range of triaryl phosphates, including 0.08% triphenyl phosphate which is above the threshold for detecting...

Performance of pineapple slips inoculated with diazotrophic phosphate-solubilizing bacteria and rock phosphate

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Lílian Estrela Borges Baldotto

2014-06-01

Full Text Available Besides fixing N2, some diazotrophic bacteria or diazotrophs, also synthesize organic acids and are able to solubilize rock phosphates, increasing the availability of P for plants. The application of these bacteria to pineapple leaf axils in combination with rock phosphate could increase N and P availability for the crop, due to the bacterial activity of biological nitrogen fixation and phosphate solubilization. The objectives of this study were: (i to select and characterize diazotrophs able to solubilize phosphates in vitro and (ii evaluate the initial performance of the pineapple cultivars Imperial and Pérola in response to inoculation with selected bacteria in combination with rock phosphate. The experiments were conducted at Universidade Estadual do Norte Fluminense Darcy Ribeiro, in 2009. In the treatments with bacteria the leaf contents of N, P and K were higher than those of the controls, followed by an increase in plant growth. These results indicate that the combined application of diazotrophic phosphate-solubilizing bacteria Burkholderia together with Araxá rock phosphate can be used to improve the initial performance of pineapple slips.

How do arbuscular mycorrhizal fungi handle phosphate? New insight into fine-tuning of phosphate metabolism.

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Ezawa, Tatsuhiro; Saito, Katsuharu

2018-04-27

Contents Summary I. Introduction II. Foraging for phosphate III. Fine-tuning of phosphate homeostasis IV. The frontiers: phosphate translocation and export V. Conclusions and outlook Acknowledgements References SUMMARY: Arbuscular mycorrhizal fungi form symbiotic associations with most land plants and deliver mineral nutrients, in particular phosphate, to the host. Therefore, understanding the mechanisms of phosphate acquisition and delivery in the fungi is critical for full appreciation of the mutualism in this association. Here, we provide updates on physical, chemical, and biological strategies of the fungi for phosphate acquisition, including interactions with phosphate-solubilizing bacteria, and those on the regulatory mechanisms of phosphate homeostasis based on resurveys of published genome sequences and a transcriptome with reference to the latest findings in a model fungus. For the mechanisms underlying phosphate translocation and export to the host, which are major research frontiers in this field, not only recent advances but also testable hypotheses are proposed. Lastly, we briefly discuss applicability of the latest tools to gene silencing in the fungi, which will be breakthrough techniques for comprehensive understanding of the molecular basis of fungal phosphate metabolism. © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

Prevalence and genetic characterization of Cryptosporidium species and Giardia duodenalis in lambs in Oromia Special Zone, Central Ethiopia.

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Wegayehu, Teklu; Karim, Md Robiul; Li, Junqiang; Adamu, Haileeyesus; Erko, Berhanu; Zhang, Longxian; Tilahun, Getachew

2017-01-17

Cryptosporidium and Giardia duodenalis are gastro-intestinal parasites that infect human and animals worldwide. Both parasites share a broad host range and are believed to be zoonosis. The aim of this study was to identify the species of Cryptosporidium and assemblages of G. duodenalis in lambs and to elucidate their role in zoonotic transmission. A total of 389 fecal samples were collected from lambs and screened by microscopy and nested PCR targeting the small-subunit ribosomal RNA for Cryptosporidium; and the small-subunit ribosomal RNA, triose phosphate isomerase, β-giardin, and glutamate dehydrogenase genes for G. duodenalis. The prevalence of Cryptosporidium and G. duodenalis was 2.1% (8/389) and 2.6% (10/389), respectively. The infection rate at the three study sites ranged from 1.3 to 3.1% for Cryptosporidium and 1.6 to 3.9% for G. duodenalis; but variation was not statistically significant (p > 0.05). The finding also showed that there is no sex and age group associated difference in the occurrence of Cryptosporidium and G. duodenalis infections in lambs. Sequence analysis revealed that lambs were mono-infection with C. ubiquitum and G. duodenalis assemblage E. The analysis also indicated the presence of genetic variation within isolates of assemblage E; with 4 of them are novel genotypes at the small-subunit ribosomal RNA, β-giardin, and glutamate dehydrogenase genes. The findings of the current study showed that lambs are capable of harboring C. ubiquitum and G. duodenalis assemblage E. This finding suggests that lambs might be sources for potentially zoonotic Cryptosporidium species. This was first molecular study in lambs and contributes to a better understanding of the epidemiology of Cryptosporidium and G. duodenalis in central Ethiopia.

Molecular systematics of the parasitic protozoan Giardia intestinalis.

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Monis, P T; Andrews, R H; Mayrhofer, G; Ey, P L

1999-09-01

The long-standing controversy regarding whether Giardia intestinalis is a single species prevalent in both human and animal hosts or a species complex consisting of morphologically similar organisms that differ in host range and other biotypic characteristics is an issue with important medical, veterinary, and environmental management implications. In the past decade, highly distinct genotypes (some apparently confined to particular host groups) have been identified by genetic analysis of samples isolated from different host species. The aim of this study was to undertake a phylogenetic analysis of G. intestinalis that were representative of all known major genetic groups and compare them with other Giardia species, viz. G. ardeae, G. muris, and G. microti. Segments from four "housekeeping" genes (specifying glutamate dehydrogenase, triose phosphate isomerase, elongation factor 1 alpha, and 18S ribosomal RNA) were examined by analysis of 0.48-0.69-kb nucleotide sequences determined from DNA amplified in polymerase chain reactions from each locus. In addition, isolates were compared by allozymic analysis of electrophoretic data obtained for 21 enzymes representing 23 gene loci. The results obtained from these independent techniques and different loci were essentially congruous. Analyses using G. ardeae and/or G. muris as outgroups supported the monophyly of G. intestinalis and also showed that this species includes genotypes that represent at least seven deeply rooted lineages, herein designated assemblages A-G. Inclusion of G. microti in the analysis of 18S rRNA sequence data demonstrated the monophyly of Giardia with the same median body morphology but did not support the monophyly of G. intestinalis, instead placing G. microti within G. intestinalis. The findings support the hypothesis that G. intestinalis is a species complex and suggest that G. microti is a member of this complex.

Molecular characterization of Cryptosporidium and Giardia in farmers and their ruminant livestock from the Coastal Savannah zone of Ghana.

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Squire, Sylvia Afriyie; Yang, Rongchang; Robertson, Ian; Ayi, Irene; Ryan, Una

2017-11-01

Cryptosporidium and Giardia are major causes of diarrhoea in developing countries including Ghana, however, nothing is known about the species and subtypes of Cryptosporidium and Giardia in farmers and their ruminant livestock in this country. A total of 925 faecal samples from humans (n=95), cattle (n=328), sheep (n=217) and goats (n=285), were screened for Cryptosporidium and Giardia by quantitative PCR (qPCR) at the 18S rRNA and glutamate dehydrogenase (gdh) loci respectively. Cryptosporidium positives were typed by sequence analysis of 18S and 60kDa glycoprotein (gp60) loci amplicons. Giardia positives were typed at the triose phosphate isomerase (tpi), beta-giardin (bg) and gdh loci. The prevalence of Cryptosporidium and Giardia by qPCR was 8.4% and 10.5% in humans, 26.5% and 8.5% in cattle, 34.1% and 12.9% in sheep, and 33.3% and 12.3% in goat faecal samples, respectively. G. duodenalis assemblages A and B were detected in humans and assemblage E was detected in livestock. Cryptosporidium parvum was the only species identified in humans; C. andersoni, C. bovis, C. ryanae and C. ubiquitum were identified in cattle; C. xiaoi, C. ubiquitum and C. bovis in sheep; and C. xiaoi, C. baileyi and C. parvum in goats. This is the first molecular study of Cryptosporidium and Giardia in livestock in Ghana. The identification of zoonotic species and the identification of C. parvum subtype IIcA5G3q in livestock, which has previously been identified in children in Ghana, suggests potential zoonotic transmission. Further studies on larger numbers of human and animal samples, and on younger livestock are required to better understand the epidemiology and transmission of Cryptosporidium and Giardia in Ghana. Copyright © 2017 Elsevier B.V. All rights reserved.

Formulation of single super phosphate fertilizer from rock phosphate of Hazara, Pakistan

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Matiullah Khan

2012-05-01

Full Text Available Phosphorus deficiency is wide spread in soils of Pakistan. It is imperative to explore the potential and economics of indigenous Hazara rock phosphate for preparation of single super phosphate fertilizer. For the subject study rock phosphate was collected from Hazara area ground at 160 mesh level with 26% total P2O5 content for manual preparation of single super phosphate fertilizer. The rock phosphate was treated with various concentrations of sulfuric acid (98.9%, diluted or pure in the field. The treatments comprised of 20 and 35% pure acid and diluted with acid-water ratios of 1:5, 1:2, 1:1 and 2:1 v/v for acidulation at the rate of 60 liters 100 kg-1 rock phosphate. The amount was prior calculated in the laboratory for complete wetting of rock phosphate. A quantity of 150 kg rock phosphate was taken as treatment. The respective amount of acid was applied with the spray pump of stainless steel or poured with bucket. After proper processing, chemical analysis of the products showed a range of available P2O5 content from 9.56 to 19.24% depending upon the amount of acid and its dilution. The results reveal at that 1:1 dilutions gave the highest P2O5 content (19.24%, lowest free acid (6 % and 32% weight increase. The application of acid beyond or below this combination either pure or diluted gave hygroscopic product and higher free acids. The cost incurred upon the manual processing was almost half the prevailing rates in the market. These results lead to conclude that application of sulfuric acid at the rate of 60 liters 100 kg-1 with the dilution of 50% (v/v can yield better kind of SSP from Hazara rock phosphate at lower prices.

Gaseous environment of plants and activity of enzymes of carbohydrate catabolism

International Nuclear Information System (INIS)

Ivanov, B.F.; Zemlyanukhin, A.A.; Igamberdiev, A.U.; Salam, A.M.M.

1989-01-01

The authors investigated the action of hypoxia and high CO 2 concentration in the atmosphere on activity of phosphofructokinase, aldolase, glucose phosphate isomerase, glucose-6-phosphate dehydrogenase, lactate dehydrogenase, alcohol dehydrogenase, and isocitrate lyase in pea seedlings (Pisum sativum L.), corn scutella (Zea mays L.), and hemp cotyledons (Cannabis sativa L.). The first 4-12h of hypoxia witnessed suppression of enzymes of the initial stages of glycolysis (glucose-6-phosphate isomerase, phosphofructokinase)and activation of enzymes of its final stages (alcohol dehydrogenase and lactate dehydrogenase) and enzymes linking glycolysis and the pentose phosphate pathway (aldolase and glucose-6-phosphate dehydrogenase). An excess of CO 2 in the environment accelerated and amplified this effect. At the end of a 24-h period of anaerobic incubation, deviations of enzyme activity from the control were leveled in both gaseous environments. An exception was observed in the case of phosphofructokinase, whose activity increased markedly at this time in plants exposed to CO 2 . Changes in activity of the enzymes were coupled with changes in their kinetic parameters (apparent K m and V max values). The activity of isocitrate lyase was suppressed in both variants of hypoxic gaseous environments, a finding that does not agree with the hypothesis as to participation of the glyoxylate cycle in the metabolic response of plants to oxygen stress. Thus, temporary inhibition of the system of glycolysis and activation of the pentose phosphate pathway constituted the initial response of the plants to O 2 stress, and CO 2 intensified this metabolic response

Integrated assessment of the phosphate industry

International Nuclear Information System (INIS)

Ryan, M.T.; Cotter, S.J.

1980-05-01

The phosphate industry in the United States includes three major activities, namely, mining and milling of phosphate rock, phosphate product manufacture, and phosphate product use. Phosphatic materials contain uranium, thorium, and their decay products in greater than background amounts. This assessment of the radiological impacts associated with the redistribution of radioactive components of phosphate materials may provide insight into the effects of uranium extraction from phosphate materials for use in the nuclear fuel cycle

Role of Phosphate Transport System Component PstB1 in Phosphate Internalization by Nostoc punctiforme.

Science.gov (United States)

Hudek, L; Premachandra, D; Webster, W A J; Bräu, L

2016-11-01

In bacteria, limited phosphate availability promotes the synthesis of active uptake systems, such as the Pst phosphate transport system. To understand the mechanisms that facilitate phosphate accumulation in the cyanobacterium Nostoc punctiforme, phosphate transport systems were identified, revealing a redundancy of Pst phosphate uptake systems that exists across three distinct operons. Four separate PstB system components were identified. pstB1 was determined to be a suitable target for creating phenotypic mutations that could result in the accumulation of excessive levels of phosphate through its overexpression or in a reduction of the capacity to accumulate phosphate through its deletion. Using quantitative real-time PCR (qPCR), it was determined that pstB1 mRNA levels increased significantly over 64 h in cells cultured in 0 mM added phosphate and decreased significantly in cells exposed to high (12.8 mM) phosphate concentrations compared to the level in cells cultured under normal (0.8 mM) conditions. Possible compensation for the loss of PstB1 was observed when pstB2, pstB3, and pstB4 mRNA levels increased, particularly in cells starved of phosphate. The overexpression of pstB1 increased phosphate uptake by N. punctiforme and was shown to functionally complement the loss of PstB in E. coli PstB knockout (PstB - ) mutants. The knockout of pstB1 in N. punctiforme did not have a significant effect on cellular phosphate accumulation or growth for the most part, which is attributed to the compensation for the loss of PstB1 by alterations in the pstB2, pstB3, and pstB4 mRNA levels. This study provides novel in vivo evidence that PstB1 plays a functional role in phosphate uptake in N. punctiforme IMPORTANCE: Cyanobacteria have been evolving over 3.5 billion years and have become highly adept at growing under limiting nutrient levels. Phosphate is crucial for the survival and prosperity of all organisms. In bacteria, limited phosphate availability promotes the

Increase in D-tagatose production rate by site-directed mutagenesis of L-arabinose isomerase from Geobacillus thermodenitrificans.

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Oh, Hyo-Jung; Kim, Hye-Jung; Oh, Deok-Kun

2006-02-01

Among single-site mutations of L-arabinose isomerase derived from Geobacillus thermodenitrificans, two mutants were produced having the lowest and highest activities of D-tagatose production. Site-directed mutagenesis at these sites showed that the aromatic ring at amino acid 164 and the size of amino acid 475 were important for D-tagatose production. Among double-site mutations, one mutant converted D-galactose into D-tagatose with a yield of 58% whereas the wild type gave 46% D-tagatose conversion after 300 min at 65 degrees C.

Effects of education on low-phosphate diet and phosphate binder intake to control serum phosphate among maintenance hemodialysis patients: A randomized controlled trial

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Eunsoo Lim

2018-03-01

Full Text Available Background : For phosphate control, patient education is essential due to the limited clearance of phosphate by dialysis. However, well-designed randomized controlled trials about dietary and phosphate binder education have been scarce. Methods : We enrolled maintenance hemodialysis patients and randomized them into an education group (n = 48 or a control group (n = 22. We assessed the patients' drug compliance and their knowledge about the phosphate binder using a questionnaire. Results : The primary goal was to increase the number of patients who reached a calcium-phosphorus product of lower than 55. In the education group, 36 (75.0% patients achieved the primary goal, as compared with 16 (72.7% in the control group (P = 0.430. The education increased the proportion of patients who properly took the phosphate binder (22.9% vs. 3.5%, P = 0.087, but not to statistical significance. Education did not affect the amount of dietary phosphate intake per body weight (education vs. control: -1.18 ± 3.54 vs. -0.88 ± 2.04 mg/kg, P = 0.851. However, the dietary phosphate-to-protein ratio tended to be lower in the education group (-0.64 ± 2.04 vs. 0.65 ± 3.55, P = 0.193. The education on phosphate restriction affected neither the Patient-Generated Subjective Global Assessment score (0.17 ± 4.58 vs. -0.86 ± 3.86, P = 0.363 nor the level of dietary protein intake (-0.03 ± 0.33 vs. -0.09 ± 0.18, P = 0.569. Conclusion : Education did not affect the calcium-phosphate product. Education on the proper timing of phosphate binder intake and the dietary phosphate-to-protein ratio showed marginal efficacy.

Zinc phosphate conversion coatings

Science.gov (United States)

Sugama, Toshifumi

1997-01-01

Zinc phosphate conversion coatings for producing metals which exhibit enhanced corrosion prevention characteristics are prepared by the addition of a transition-metal-compound promoter comprising a manganese, iron, cobalt, nickel, or copper compound and an electrolyte such as polyacrylic acid, polymethacrylic acid, polyitaconic acid and poly-L-glutamic acid to a phosphating solution. These coatings are further improved by the incorporation of Fe ions. Thermal treatment of zinc phosphate coatings to generate .alpha.-phase anhydrous zinc phosphate improves the corrosion prevention qualities of the resulting coated metal.

Cyclophilin40 isomerase activity is regulated by a temperature-dependent allosteric interaction with Hsp90.

Science.gov (United States)

Blackburn, Elizabeth A; Wear, Martin A; Landré, Vivian; Narayan, Vikram; Ning, Jia; Erman, Burak; Ball, Kathryn L; Walkinshaw, Malcolm D

2015-09-01

Cyclophilin 40 (Cyp40) comprises an N-terminal cyclophilin domain with peptidyl-prolyl isomerase (PPIase) activity and a C-terminal tetratricopeptide repeat (TPR) domain that binds to the C-terminal-EEVD sequence common to both heat shock protein 70 (Hsp70) and Hsp90. We show in the present study that binding of peptides containing the MEEVD motif reduces the PPIase activity by ∼30%. CD and fluorescence assays show that the TPR domain is less stable than the cyclophilin domain and is stabilized by peptide binding. Isothermal titration calorimetry (ITC) shows that the affinity for the-MEEVD peptide is temperature sensitive in the physiological temperature range. Results from these biophysical studies fit with the MD simulations of the apo and holo (peptide-bound) structures which show a significant reduction in root mean square (RMS) fluctuation in both TPR and cyclophilin domains when-MEEVD is bound. The MD simulations of the apo-protein also highlight strong anti-correlated motions between residues around the PPIase-active site and a band of residues running across four of the seven helices in the TPR domain. Peptide binding leads to a distortion in the shape of the active site and a significant reduction in these strongly anti-correlated motions, providing an explanation for the allosteric effect of ligand binding and loss of PPIase activity. Together the experimental and MD results suggest that on heat shock, dissociation of Cyp40 from complexes mediated by the TPR domain leads to an increased pool of free Cyp40 capable of acting as an isomerase/chaperone in conditions of cellular stress. © 2015 Authors.

D-Allose catabolism of Escherichia coli

DEFF Research Database (Denmark)

Poulsen, Tim S.; Chang, Ying-Ying; Hove-Jensen, Bjarne

1999-01-01

Genes involved in allose utilization of Escherichia coli K-12 are organized in at least two operons, alsRBACE and alsI, located next to each other on the chromosome but divergently transcribed. Mutants defective in alsI (allose 6-phosphate isomerase gene) and alsE (allulose 6-phosphate epimerase...... gene) were Als-. Transcription of the two allose operons, measured as β-galactosidase activity specified by alsI-lacZ+ or alsE-lacZ+ operon fusions, was induced by allose. Ribose also caused derepression of expression of the regulon under conditions in which ribose phosphate catabolism was impaired....

Hemodialysis for near-fatal sodium phosphate toxicity in a child receiving sodium phosphate enemas.

Science.gov (United States)

Becknell, Brian; Smoyer, William E; O'Brien, Nicole F

2014-11-01

This study aimed to demonstrate the importance of considering hemodialysis as a treatment option in the management of sodium phosphate toxicity. This is a case report of a 4-year-old who presented to the emergency department with shock, decreased mental status, seizures, and tetany due to sodium phosphate toxicity from sodium phosphate enemas. Traditional management of hyperphosphatemia with aggressive hydration and diuretics was insufficient to reverse the hemodynamic and neurological abnormalities in this child. This is the first report of the use of hemodialysis in a child without preexisting renal failure for the successful management of near-fatal sodium phosphate toxicity. Hemodialysis can safely be used as an adjunctive therapy in sodium phosphate toxicity to rapidly reduce serum phosphate levels and increase serum calcium levels in children not responding to conventional management.

Continuous D-tagatose production by immobilized thermostable L-arabinose isomerase in a packed-bed bioreactor.

Science.gov (United States)

Ryu, Se-Ah; Kim, Chang Sup; Kim, Hye-Jung; Baek, Dae Heoun; Oh, Deok-Kun

2003-01-01

D-Tagatose was continuously produced using thermostable L-arabinose isomerase immobilized in alginate with D-galactose solution in a packed-bed bioreactor. Bead size, L/D (length/diameter) of reactor, dilution rate, total loaded enzyme amount, and substrate concentration were found to be optimal at 0.8 mm, 520/7 mm, 0.375 h(-1), 5.65 units, and 300 g/L, respectively. Under these conditions, the bioreactor produced about 145 g/L tagatose with an average productivity of 54 g tagatose/L x h and an average conversion yield of 48% (w/w). Operational stability of the immobilized enzyme was demonstrated, with a tagatose production half-life of 24 days.

Phosphate transporter mediated lipid accumulation in Saccharomyces cerevisiae under phosphate starvation conditions.

Science.gov (United States)

James, Antoni W; Nachiappan, Vasanthi

2014-01-01

In the current study, when phosphate transporters pho88 and pho86 were knocked out they resulted in significant accumulation (84% and 43%) of triacylglycerol (TAG) during phosphate starvation. However in the presence of phosphate, TAG accumulation was only around 45% in both pho88 and pho86 mutant cells. These observations were confirmed by radio-labeling, fluorescent microscope and RT-PCR studies. The TAG synthesizing genes encoding for acyltransferases namely LRO1 and DGA1 were up regulated. This is the first report for accumulation of TAG in pho88Δ and pho86Δ cells under phosphate starvation conditions. Copyright © 2013. Published by Elsevier Ltd.

21 CFR 137.175 - Phosphated flour.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Phosphated flour. 137.175 Section 137.175 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Related Products § 137.175 Phosphated flour. Phosphated flour, phosphated white flour, and phosphated...

Single zymomonas mobilis strain for xylose and arabinose fermentation

Science.gov (United States)

Zhang, Min; Chou, Yat-Chen; Picataggio, Stephen K.; Finkelstein, Mark

1998-01-01

This invention relates to single microorganisms which normally do not ferment pentose sugars which are genetically altered to ferment the pentose sugars, xylose and arabinose, to produce ethanol, and a fermentation process utilizing the same. Examples include Zymomonas mobilis which has been transformed with a combination of E. coli genes for xylose isomerase, xylulokinase, L-arabinose isomerase, L-ribulokinase, L-ribulose 5-phosphate 4-epimerase, transaldolase and transketolase. Expression of added genes are under the control of Z. mobilis promoters. These newly created microorganisms are useful for fermenting glucose, xylose and arabinose, produced by hydrolysis of hemicellulose and cellulose or starch, to produce ethanol.

Optimization of ATP synthase function in mitochondria and chloroplasts via the adenylate kinase equilibrium

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Abir U Igamberdiev

2015-01-01

Full Text Available The bulk of ATP synthesis in plants is performed by ATP synthase, the main bioenergetics engine of cells, operating both in mitochondria and in chloroplasts. The reaction mechanism of ATP synthase has been studied in detail for over half a century; however, its optimal performance depends also on the steady delivery of ATP synthase substrates and the removal of its products. For mitochondrial ATP synthase, we analyze here the provision of stable conditions for (i the supply of ADP and Mg2+, supported by adenylate kinase (AK equilibrium in the intermembrane space, (ii the supply of phosphate via membrane transporter in symport with H+, and (iii the conditions of outflow of ATP by adenylate transporter carrying out the exchange of free adenylates. We also show that, in chloroplasts, AK equilibrates adenylates and governs Mg2+ contents in the stroma, optimizing ATP synthase and Calvin cycle operation, and affecting the import of inorganic phosphate in exchange with triose phosphates. It is argued that chemiosmosis is not the sole component of ATP synthase performance, which also depends on AK-mediated equilibrium of adenylates and Mg2+, adenylate transport and phosphate release and supply.

FabQ, a Dual-Function Dehydratase/Isomerase, Circumvents the Last Step of the Classical Fatty Acid Synthesis Cycle

OpenAIRE

Bi, Hongkai; Wang, Haihong; Cronan, John E.

2013-01-01

In the classical anaerobic pathway of unsaturated fatty acid biosynthesis, that of Escherichia coli, the double bond is introduced into the growing acyl chain by the FabA dehydratase/isomerase. Another dehydratase, FabZ, functions in the chain elongation cycle. In contrast, Aerococcus viridans has only a single FabA/FabZ homolog we designate FabQ. FabQ can not only replace the function of E. coli FabZ in vivo, but it also catalyzes the isomerization required for unsaturated fatty acid biosynt...

Inhibition of d-xylose isomerase by polyols: atomic details by joint X-ray/neutron crystallography

Energy Technology Data Exchange (ETDEWEB)

Kovalevsky, Andrey, E-mail: ayk@lanl.gov [Los Alamos National Laboratory, PO Box 1663, MS M888, Los Alamos, NM 87545 (United States); Hanson, B. Leif [University of Toledo, 2801 West Bancroft Street, Toledo, OH 43606 (United States); Mason, Sax A. [Institut Laue–Langevin, 6 Rue Jules Horowitz, 38042 Grenoble (France); Forsyth, V. Trevor [Institut Laue–Langevin, 6 Rue Jules Horowitz, 38042 Grenoble (France); Keele University, Staffordshire (United Kingdom); Fisher, Zoe [Los Alamos National Laboratory, PO Box 1663, MS M888, Los Alamos, NM 87545 (United States); Mustyakimov, Marat [Los Alamos National Laboratory, PO Box 1663, MS M888, Los Alamos, NM 87545 (United States); Oak Ridge National Laboratory, PO Box 2008, MS 6475, Oak Ridge, TN 37831 (United States); Blakeley, Matthew P. [Institut Laue–Langevin, 6 Rue Jules Horowitz, 38042 Grenoble (France); Keen, David A. [Harwell Science and Innovation Campus, Didcot, Oxon OX11 0QX (United Kingdom); Langan, Paul [Oak Ridge National Laboratory, PO Box 2008, MS 6475, Oak Ridge, TN 37831 (United States); Los Alamos National Laboratory, PO Box 1663, MS M888, Los Alamos, NM 87545 (United States)

2012-09-01

A joint X-ray/neutron structure of d-xylose isomerase in complex with the inhibitor sorbitol was determined at room temperature at an acidic pH of 5.9. Protonation of the O5 O atom of the sugar was directly observed in the nuclear density maps. Under acidic conditions sorbitol gains a water-mediated interaction with the enzyme active site, which may explain the increased potency of the inhibitor at low pH. d-Xylose isomerase (XI) converts the aldo-sugars xylose and glucose to their keto analogs xylulose and fructose, but is strongly inhibited by the polyols xylitol and sorbitol, especially at acidic pH. In order to understand the atomic details of polyol binding to the XI active site, a 2.0 Å resolution room-temperature joint X-ray/neutron structure of XI in complex with Ni{sup 2+} cofactors and sorbitol inhibitor at pH 5.9 and a room-temperature X-ray structure of XI containing Mg{sup 2+} ions and xylitol at the physiological pH of 7.7 were obtained. The protonation of oxygen O5 of the inhibitor, which was found to be deprotonated and negatively charged in previous structures of XI complexed with linear glucose and xylulose, was directly observed. The Ni{sup 2+} ions occupying the catalytic metal site (M2) were found at two locations, while Mg{sup 2+} in M2 is very mobile and has a high B factor. Under acidic conditions sorbitol gains a water-mediated interaction that connects its O1 hydroxyl to Asp257. This contact is not found in structures at basic pH. The new interaction that is formed may improve the binding of the inhibitor, providing an explanation for the increased affinity of the polyols for XI at low pH.

The first case of a complete deficiency of diphosphoglycerate mutase in human erythrocytes.

Science.gov (United States)

Rosa, R; Prehu, M O; Beuzard, Y; Rosa, J

1978-01-01

An inherited and complete deficiency of diphosphoglycerate mutase was discovered in the erythrocytes of a 42-yr-old man of French origin whose blood hemoglobin concentration was 19.0 g/dl. Upon physical examination he was normal with the exception of a ruddy cyanosis. The morphology of his erythrocytes was also normal and there was no evidence of hemolysis. The erythrocyte 2,3-diphosphoglycerate level was below 3% of normal values and, as a consequence, the affinity of the cells for oxygen was increased. Diphosphoglycerate mutase activity was undetectable in erythrocytes as was that of diphosphoglycerate phosphatase. The activities of all the other erythrocyte enzymes that were tested were normal except for nomophosphoglycerate mutase which was diminished to 50% of the normal value. The levels of reduced glutathione, ATP, fructose 1,6-diphosphate, and of triose phosphates were elevated, whereas those of glucose 6-phosphate and fructose 6-phosphate were decreased. This report sheds new light on the role of diphosphoglycerate mutase in the metabolism of erythrocytes. Images PMID:152321

Radioactivity of phosphate ores from Karatas-Mazidag phosphate deposit of Turkey

International Nuclear Information System (INIS)

Akyuez, T.; Varinlioglu, A.; Kose, A.; Akyuez, S.

2000-01-01

The specific activities of 238 U, 226 Ra, 232 Th and 40 K in the composite samples of phosphate ores of type I (grey-coloured ore, with high P 2 O 5 (21-35%) and low calcite content) and of type II (grey coloured calcite ore, with low P 2 O 5 content (5-17%)) of Karatas-Mazidag phosphate deposit, Turkey, have been determined by gamma spectrometry together with phosphatic animal feed ingredients. The concentrations of 238 U, 226 Ra, 232 Th and 40 K were found to be up to 557, 625, 26 and 297 Bq x kg -1 , respectively. Radium equivalent activities of samples were calculated and compared with those given in the literature. Uranium concentration of the individual phosphate samples, from which composite samples of ores of type I and II have been prepared, were found to show and increasing trend with increasing P 2 O 5 and F concentrations. (author)

Phosphate application to firing range soils for Pb immobilization: The unclear role of phosphate

International Nuclear Information System (INIS)

Chrysochoou, Maria; Dermatas, Dimitris; Grubb, Dennis G.

2007-01-01

Phosphate treatment has emerged as a widely accepted approach to immobilize Pb in contaminated soils and waste media, relying on the formation of the highly insoluble mineral pyromorphite as solubility-controlling phase for Pb. As such, phosphate treatment has been proposed as a Best Management Practice (BMP) for firing ranges where Pb occurs in its metallic forms and several other phases (carbonates, oxides). While pyromorphite thermodynamically has the potential to control Pb solubility at low levels, its formation is kinetically controlled by pH, the solubility of the phosphate source, and the solubility of Pb species. Treatability studies have shown that excess quantities of soluble and acidic phosphate sources, such as phosphoric acid, are necessary for successful in situ treatment. Even under these conditions, Extended X-ray Absorption Fine Structure (EXAFS), the only reliable method to identify and quantify Pb speciation, showed that Pb conversion to pyromorphite in in situ treated soils was less than 45% after 32 months. Furthermore, the use of lime (CaO) to restore soil pH in acidified soil treatments inhibited further conversion. Additionally, phosphate treatment is known to reduce bioavailability through pyromorphite formation in the intestinal tract, and the phytoaccumulation of Pb; both desirable effects for Pb-impacted areas. Given the costs of phosphate treatment, the use of biogenic phosphate sources, such as bone meal, may be a more environmentally sustainable approach toward this end. In the many studies focusing on phosphate treatment, the attendant P leaching and eutrophication have been largely overlooked, along with other issues such as the enhanced leaching of oxyanionic contaminants, such as Se, As and W. The success and sustainability of applying phosphate as a BMP in firing range soils therefore remain questionable

Method of stripping plutonium from tributyl phosphate solution which contains dibutyl phosphate-plutonium stable complexes

International Nuclear Information System (INIS)

Ochsenfeld, W.; Schmieder, H.

1976-01-01

Fast breeder fuel elements which have been highly burnt-up are reprocessed by extracting uranium and plutonium into an organic solution containing tributyl phosphate. The tributyl phosphate degenerates at least partially into dibutyl phosphate and monobutyl phosphate, which form stable complexes with tetravalent plutonium in the organic solution. This tetravalent plutonium is released from its complexed state and stripped into aqueous phase by contacting the organic solution with an aqueous phase containing tetravalent uranium. 6 claims, 1 drawing figure

Phosphate control in dialysis

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Cupisti A

2013-10-01

Full Text Available Adamasco Cupisti,1 Maurizio Gallieni,2 Maria Antonietta Rizzo,2 Stefania Caria,3 Mario Meola,4 Piergiorgio Bolasco31Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy; 2Nephrology and Dialysis Unit, San Carlo Borromeo Hospital, Milan, Italy; 3Territorial Department of Nephrology and Dialysis, ASL Cagliari, Italy; 4Sant'Anna School of Advanced Studies, University of Pisa, Pisa, ItalyAbstract: Prevention and correction of hyperphosphatemia is a major goal of chronic kidney disease–mineral and bone disorder (CKD–MBD management, achievable through avoidance of a positive phosphate balance. To this aim, optimal dialysis removal, careful use of phosphate binders, and dietary phosphate control are needed to optimize the control of phosphate balance in well-nourished patients on a standard three-times-a-week hemodialysis schedule. Using a mixed diffusive–convective hemodialysis tecniques, and increasing the number and/or the duration of dialysis tecniques are all measures able to enhance phosphorus (P mass removal through dialysis. However, dialytic removal does not equal the high P intake linked to the high dietary protein requirement of dialysis patients; hence, the use of intestinal P binders is mandatory to reduce P net intestinal absorption. Unfortunately, even a large dose of P binders is able to bind approximately 200–300 mg of P on a daily basis, so it is evident that their efficacy is limited in the case of an uncontrolled dietary P load. Hence, limitation of dietary P intake is needed to reach the goal of neutral phosphate balance in dialysis, coupled to an adequate protein intake. To this aim, patients should be informed and educated to avoid foods that are naturally rich in phosphate and also processed food with P-containing preservatives. In addition, patients should preferentially choose food with a low P-to-protein ratio. For example, patients could choose egg white or protein from a vegetable source

Performance of pineapple slips inoculated with diazotrophic phosphate-solubilizing bacteria and rock phosphate

OpenAIRE

Lílian Estrela Borges Baldotto; Marihus Altoé Baldotto; Fábio Lopes Olivares; Adriane Nunes de Souza

2014-01-01

Besides fixing N2, some diazotrophic bacteria or diazotrophs, also synthesize organic acids and are able to solubilize rock phosphates, increasing the availability of P for plants. The application of these bacteria to pineapple leaf axils in combination with rock phosphate could increase N and P availability for the crop, due to the bacterial activity of biological nitrogen fixation and phosphate solubilization. The objectives of this study were: (i) to select and characterize diazotrophs abl...

Cloning, expression and characterization of L-arabinose isomerase from Thermotoga neapolitana: bioconversion of D-galactose to D-tagatose using the enzyme.

Science.gov (United States)

Kim, Byoung-Chan; Lee, Yoon-Hee; Lee, Han-Seung; Lee, Dong-Woo; Choe, Eun-Ah; Pyun, Yu-Ryang

2002-06-18

Gene araA encoding an L-arabinose isomerase (AraA) from the hyperthermophile, Thermotoga neapolitana 5068 was cloned, sequenced, and expressed in Escherichia coli. The gene encoded a polypeptide of 496 residues with a calculated molecular mass of 56677 Da. The deduced amino acid sequence has 94.8% identical amino acids compared with the residues in a putative L-arabinose isomerase of Thermotoga maritima. The recombinant enzyme expressed in E. coli was purified to homogeneity by heat treatment, ion exchange chromatography and gel filtration. The thermophilic enzyme had a maximum activity of L-arabinose isomerization and D-galactose isomerization at 85 degrees C, and required divalent cations such as Co(2+) and Mn(2+) for its activity and thermostability. The apparent K(m) values of the enzyme for L-arabinose and D-galactose were 116 mM (v(max), 119 micromol min(-1) mg(-1)) and 250 mM (v(max), 14.3 micromol min(-1) mg(-1)), respectively, that were determined in the presence of both 1 mM Co(2+) and 1 mM Mn(2+). A 68% conversion of D-galactose to D-tagatose was obtained using the recombinant enzyme at the isomerization temperature of 80 degrees C.

On the structure and function of the phytoene desaturase CRTI from Pantoea ananatis, a membrane-peripheral and FAD-dependent oxidase/isomerase.

Directory of Open Access Journals (Sweden)

Patrick Schaub

Full Text Available CRTI-type phytoene desaturases prevailing in bacteria and fungi can form lycopene directly from phytoene while plants employ two distinct desaturases and two cis-tans isomerases for the same purpose. This property renders CRTI a valuable gene to engineer provitamin A-formation to help combat vitamin A malnutrition, such as with Golden Rice. To understand the biochemical processes involved, recombinant CRTI was produced and obtained in homogeneous form that shows high enzymatic activity with the lipophilic substrate phytoene contained in phosphatidyl-choline (PC liposome membranes. The first crystal structure of apo-CRTI reveals that CRTI belongs to the flavoprotein superfamily comprising protoporphyrinogen IX oxidoreductase and monoamine oxidase. CRTI is a membrane-peripheral oxidoreductase which utilizes FAD as the sole redox-active cofactor. Oxygen, replaceable by quinones in its absence, is needed as the terminal electron acceptor. FAD, besides its catalytic role also displays a structural function by enabling the formation of enzymatically active CRTI membrane associates. Under anaerobic conditions the enzyme can act as a carotene cis-trans isomerase. In silico-docking experiments yielded information on substrate binding sites, potential catalytic residues and is in favor of single half-site recognition of the symmetrical C(40 hydrocarbon substrate.

Insights into the evolution of enzyme substrate promiscuity after the discovery of (βα)₈ isomerase evolutionary intermediates from a diverse metagenome.

Science.gov (United States)

Noda-García, Lianet; Juárez-Vázquez, Ana L; Ávila-Arcos, María C; Verduzco-Castro, Ernesto A; Montero-Morán, Gabriela; Gaytán, Paul; Carrillo-Tripp, Mauricio; Barona-Gómez, Francisco

2015-06-10

Current sequence-based approaches to identify enzyme functional shifts, such as enzyme promiscuity, have proven to be highly dependent on a priori functional knowledge, hampering our ability to reconstruct evolutionary history behind these mechanisms. Hidden Markov Model (HMM) profiles, broadly used to classify enzyme families, can be useful to distinguish between closely related enzyme families with different specificities. The (βα)8-isomerase HisA/PriA enzyme family, involved in L-histidine (HisA, mono-substrate) biosynthesis in most bacteria and plants, but also in L-tryptophan (HisA/TrpF or PriA, dual-substrate) biosynthesis in most Actinobacteria, has been used as model system to explore evolutionary hypotheses and therefore has a considerable amount of evolutionary, functional and structural knowledge available. We searched for functional evolutionary intermediates between the HisA and PriA enzyme families in order to understand the functional divergence between these families. We constructed a HMM profile that correctly classifies sequences of unknown function into the HisA and PriA enzyme sub-families. Using this HMM profile, we mined a large metagenome to identify plausible evolutionary intermediate sequences between HisA and PriA. These sequences were used to perform phylogenetic reconstructions and to identify functionally conserved amino acids. Biochemical characterization of one selected enzyme (CAM1) with a mutation within the functionally essential N-terminus phosphate-binding site, namely, an alanine instead of a glycine in HisA or a serine in PriA, showed that this evolutionary intermediate has dual-substrate specificity. Moreover, site-directed mutagenesis of this alanine residue, either backwards into a glycine or forward into a serine, revealed the robustness of this enzyme. None of these mutations, presumably upon functionally essential amino acids, significantly abolished its enzyme activities. A truncated version of this enzyme (CAM2

Uranium-phosphate relationship in phosphated chalks of the Mons and Picardie Bassins

Energy Technology Data Exchange (ETDEWEB)

Quinif, Y; Charlet, J M; Dupuis, C; Robaszynski, F [Faculte Polytechnique de Mons (Belgium)

1981-11-30

The lithological and geochemical conditions relative to the ''Senonian'' phosphatic chalks are relatively simple in the Basins of Mons (Belgium) and of Picardy (France). Their characteristics permit us to study chiefly the uranium-phosphate relation. It appears a very good linear correlation between the phosphate and the uranium. The coefficient U/P/sub 2/O/sub 5/ remains a constant from the bottom to the top of the same section, but changes in space for synchronic formations (lateral variation of geochemical facies) and in time for two separated basins.

Uranium abundance in some sudanese phosphate ores

International Nuclear Information System (INIS)

Adam, A.A.; Eltayeb, M.A.H.

2009-01-01

This work was carried out mainly to analysis of some Sudanese phosphate ores, for their uranium abundance and total phosphorus content measured as P 2 O 5 %. For this purpose, 30 samples of two types of phosphate ore from Eastern Nuba Mountains, in Sudan namely, Kurun and Uro areas were examined. In addition, the relationship between uranium and major, and trace elements were obtained, also, the natural radioactivity of the phosphate samples was measured, in order to characterize and differentiate between the two types of phosphate ores. The uranium abundance in Uro phosphate with 20.3% P 2 O 5 is five time higher than in Kurun phosphate with 26.7% P 2 O 5 . The average of uranium content was found to be 56.6 and 310 mg/kg for Kurun and Uro phosphate ore, respectively. The main elements in Kurun and Uro phosphate ore are silicon, aluminum, and phosphorus, while the most abundant trace elements in these two ores are titanium, strontium and barium. Pearson correlation coefficient revealed that uranium in Kurun phosphate shows strong positive correlation with P 2 O 5 , and its distribution is essentially controlled by the variations of P2O5 concentration, whereas uranium in Uro phosphate shows strong positive correlation with strontium, and its distribution is controlled by the variations of Sr concentration. Uranium behaves in different ways in Kurun phosphate and in Uro phosphate. Uro phosphate shows higher concentrations of all the estimated radionuclides than Kurun phosphate. According to the obtained results, it can be concluded that Uro phosphate is consider as secondary uranium source, and is more suitable for uranium recovery, because it has high uranium abundance and low P 2 O 5 %, than Kurun phosphate. (authors) [es

Uranium from phosphate ores

International Nuclear Information System (INIS)

Hurst, F.J.

1983-01-01

The following topics are described briefly: the way phosphate fertilizers are made; how uranium is recovered in the phosphate industry; and how to detect covert uranium recovery operations in a phsophate plant

Electrochemical Reduction of Zinc Phosphate

International Nuclear Information System (INIS)

Kim, Chang Hwan; Lee, Jung Hyun; Shin, Woon Sup

2010-01-01

We demonstrated first that the electrochemical reduction of zinc phosphate in neutral phosphate buffer is possible and potentially applicable to bio-compatible rechargeable battery. The actual redox component is Zn(s)/Zn phosphate(s) and the future research about the control of crystal formation for the better cyclability is required. In lead-acid battery, the electrochemical redox reaction of Pb (s) /PbSO 4(s) is used by reducing Pb(II) and oxidizing Pb(0) in sulfate rich solution. Since both reduced form and oxidized form are insoluble, they cannot diffuse to the opposite electrodes and react. It is a very common strategy to make a stable battery electrode that a metal element is reduced and oxidized in solution containing an abundance of anion readily precipitating with the metal ion. For the application of this strategy to construction of rechargeable battery using bio-compatible electrode materials and electrolytes, the use of phosphate ion can be considered as anion readily precipitating with metal ions. If phosphate buffer with neutral pH is used as electrolyte, the better bio-compatibility will be achieved than most of rechargeable battery using strong acid, strong base or organic solvent as electrolyte solution. There are many metal ions readily precipitating with phos-phate ion, and zinc is one of them

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.

The effects of disruption of phosphoglucose isomerase gene on carbon utilisation and cellulase production in Trichoderma reesei Rut-C30

Science.gov (United States)

2011-01-01

Background Cellulase and hemicellulase genes in the fungus Trichoderma reesei are repressed by glucose and induced by lactose. Regulation of the cellulase genes is mediated by the repressor CRE1 and the activator XYR1. T. reesei strain Rut-C30 is a hypercellulolytic mutant, obtained from the natural strain QM6a, that has a truncated version of the catabolite repressor gene, cre1. It has been previously shown that bacterial mutants lacking phosphoglucose isomerase (PGI) produce more nucleotide precursors and amino acids. PGI catalyzes the second step of glycolysis, the formation of fructose-6-P from glucose-6-P. Results We deleted the gene pgi1, encoding PGI, in the T. reesei strain Rut-C30 and we introduced the cre1 gene in a Δpgi1 mutant. Both Δpgi1 and cre1+Δpgi1 mutants showed a pellet-like and growth as well as morphological alterations compared with Rut-C30. None of the mutants grew in media with fructose, galactose, xylose, glycerol or lactose but they grew in media with glucose, with fructose and glucose, with galactose and fructose or with lactose and fructose. No growth was observed in media with xylose and glucose. On glucose, Δpgi1 and cre1+Δpgi1 mutants showed higher cellulase activity than Rut-C30 and QM6a, respectively. But in media with lactose, none of the mutants improved the production of the reference strains. The increase in the activity did not correlate with the expression of mRNA of the xylanase regulator gene, xyr1. Δpgi1 mutants were also affected in the extracellular β-galactosidase activity. Levels of mRNA of the glucose 6-phosphate dehydrogenase did not increase in Δpgi1 during growth on glucose. Conclusions The ability to grow in media with glucose as the sole carbon source indicated that Trichoderma Δpgi1 mutants were able to use the pentose phosphate pathway. But, they did not increase the expression of gpdh. Morphological characteristics were the result of the pgi1 deletion. Deletion of pgi1 in Rut-C30 increased cellulase

Effect of combined gamma-irradiation and storage on biochemical changes in sweet potato

International Nuclear Information System (INIS)

Ajlouni, S.; Hamdy, M.K.

1988-01-01

Sucrose of uncured Red Jewel sweet potato increased from 3.8% to 10.7% after a combined treatment of a 300 Krad dose ( 60 Co) and 4 days storage at 24 0 C post-irradiation (PI). Starch decreased from 16.8% to 6.1% after 16 days following a 500 Krad treatment. Phosphorylase, phosphoglucomutase and sucrose phosphate synthase enzyme specific activities increase 2.4-, 1.8- and 1.3-fold, respectively, after 3 days PI following 200 Krad exposures compared to nonirradiated roots. The beta-Amylase, phosphoglucose isomerase and sucrose synthase specific activities increased 1.2-fold. Sucrose synthesis in the irradiated sweet potato was attributed to beta-amylase, phosphorylase, phosphoglucomutase, phosphoglucose isomerase and sucrose synthase

Calcium phosphates: what is the evidence?

Science.gov (United States)

Larsson, Sune

2010-03-01

A number of different calcium phosphate compounds such as calcium phosphate cements and solid beta-tricalcium phosphate products have been introduced during the last decade. The chemical composition mimics the mineral phase of bone and as a result of this likeness, the materials seem to be remodeled as for normal bone through a cell-mediated process that involves osteoclastic activity. This is a major difference when compared with, for instance, calcium sulphate compounds that after implantation dissolve irrespective of the new bone formation rate. Calcium phosphates are highly biocompatible and in addition, they act as synthetic osteoconductive scaffolds after implantation in bone. When placed adjacent to bone, osteoid is formed directly on the surface of the calcium phosphate with no soft tissue interposed. Remodeling is slow and incomplete, but by adding more and larger pores, like in ultraporous beta-tricalcium phosphate, complete or nearly complete resorption can be achieved. The indications explored so far include filling of metaphyseal fracture voids or bone cysts, a volume expander in conjunction with inductive products, and as a carrier for various growth factors and antibiotics. Calcium phosphate compounds such as calcium phosphate cement and beta-tricalcium phosphate will most certainly be part of the future armamentarium when dealing with fracture treatment. It is reasonable to believe that we have so far only seen the beginning when it comes to clinical applications.

Roles of Prolyl Isomerases in RNA-Mediated Gene Expression

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Roopa Thapar

2015-05-01

Full Text Available The peptidyl-prolyl cis-trans isomerases (PPIases that include immunophilins (cyclophilins and FKBPs and parvulins (Pin1, Par14, Par17 participate in cell signaling, transcription, pre-mRNA processing and mRNA decay. The human genome encodes 19 cyclophilins, 18 FKBPs and three parvulins. Immunophilins are receptors for the immunosuppressive drugs cyclosporin A, FK506, and rapamycin that are used in organ transplantation. Pin1 has also been targeted in the treatment of Alzheimer’s disease, asthma, and a number of cancers. While these PPIases are characterized as molecular chaperones, they also act in a nonchaperone manner to promote protein-protein interactions using surfaces outside their active sites. The immunosuppressive drugs act by a gain-of-function mechanism by promoting protein-protein interactions in vivo. Several immunophilins have been identified as components of the spliceosome and are essential for alternative splicing. Pin1 plays roles in transcription and RNA processing by catalyzing conformational changes in the RNA Pol II C-terminal domain. Pin1 also binds several RNA binding proteins such as AUF1, KSRP, HuR, and SLBP that regulate mRNA decay by remodeling mRNP complexes. The functions of ribonucleoprotein associated PPIases are largely unknown. This review highlights PPIases that play roles in RNA-mediated gene expression, providing insight into their structures, functions and mechanisms of action in mRNP remodeling in vivo.

Cloning of araA Gene Encoding L-Arabinose Isomerase from Marine Geobacillus stearothermophilus Isolated from Tanjung Api, Poso, Indonesia

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DEWI FITRIANI

2010-06-01

Full Text Available L-arabinose isomerase is an enzyme converting D-galactose to D-tagatose. D-tagatose is a potential sweetener-sucrose substitute which has low calorie. This research was to clone and sequence araA gene from marine bacterial strain Geobacillus stearothermophilus isolated from Tanjung Api Poso Indonesia. The amplified araA gene consisted of 1494 bp nucleotides encoding 497 amino acids. DNA alignment analysis showed that the gene had high homology with that of G. stearothermophilus T6. The enzyme had optimum activity at high temperature and alkalin condition.

Phosphate additives in food--a health risk.

Science.gov (United States)

Ritz, Eberhard; Hahn, Kai; Ketteler, Markus; Kuhlmann, Martin K; Mann, Johannes

2012-01-01

Hyperphosphatemia has been identified in the past decade as a strong predictor of mortality in advanced chronic kidney disease (CKD). For example, a study of patients in stage CKD 5 (with an annual mortality of about 20%) revealed that 12% of all deaths in this group were attributable to an elevated serum phosphate concentration. Recently, a high-normal serum phosphate concentration has also been found to be an independent predictor of cardiovascular events and mortality in the general population. Therefore, phosphate additives in food are a matter of concern, and their potential impact on health may well have been underappreciated. We reviewed pertinent literature retrieved by a selective search of the PubMed and EU databases (www.zusatzstoffe-online.de, www.codexalimentarius.de), with the search terms "phosphate additives" and "hyperphosphatemia." There is no need to lower the content of natural phosphate, i.e. organic esters, in food, because this type of phosphate is incompletely absorbed; restricting its intake might even lead to protein malnutrition. On the other hand, inorganic phosphate in food additives is effectively absorbed and can measurably elevate the serum phosphate concentration in patients with advanced CKD. Foods with added phosphate tend to be eaten by persons at the lower end of the socioeconomic scale, who consume more processed and "fast" food. The main pathophysiological effect of phosphate is vascular damage, e.g. endothelial dysfunction and vascular calcification. Aside from the quality of phosphate in the diet (which also requires attention), the quantity of phosphate consumed by patients with advanced renal failure should not exceed 1000 mg per day, according to the guidelines. Prospective controlled trials are currently unavailable. In view of the high prevalence of CKD and the potential harm caused by phosphate additives to food, the public should be informed that added phosphate is damaging to health. Furthermore, calls for labeling

Phosphate analysis of natural sausage casings preserved in brines with phosphate additives as inactivating agent - Method validation.

Science.gov (United States)

Wijnker, J J; Tjeerdsma-van Bokhoven, J L M; Veldhuizen, E J A

2009-01-01

Certain phosphates have been identified as suitable additives for the improvement of the microbial and mechanical properties of processed natural sausage casings. When mixed with NaCl (sodium chloride) and used under specific treatment and storage conditions, these phosphates are found to prevent the spread of foot-and-mouth disease and classical swine fever via treated casings. The commercially available Quantichrom™ phosphate assay kit has been evaluated as to whether it can serve as a reliable and low-tech method for routine analysis of casings treated with phosphate. The outcome of this study indicates that this particular assay kit has sufficient sensitivity to qualitatively determine the presence of phosphate in treated casings without interference of naturally occurring phosphate in salt used for brines in which casings are preserved.

Characterization of a calcium phosphate cement based on alpha-tricalcium phosphate obtained by wet precipitation process

International Nuclear Information System (INIS)

Thurmer, M.B.; Diehl, C.E.; Vieira, R.S.; Coelho, W.T.G.; Santos, L.A.

2012-01-01

There are several systems of calcium phosphate cements being studied. Those based on alpha-tricalcium phosphate are of particular interest. After setting they produce calcium deficient hydroxyapatite similar to bone like hydroxyapatite. This work aims to obtain alpha-tricalcium phosphate powders by the wet precipitation process, using calcium nitrate and phosphoric acid as reagents. This powder was characterized by infrared spectroscopy, X-ray diffraction and particle size distribution. In order to prepare the calcium phosphate cement, the powder was mixed with an accelerator in an aqueous solution. The mechanical properties of the cement were assessed and it was evaluated by means of apparent density, X-ray diffraction and scanning electron microscopy. The described method produced crystalline alpha-tricalcium phosphate as the major phase. The calcium phosphate cement showed high values of compression strength (50 MPa). The soaking of the cement in a simulated body fluid (SBF) formed a layer of hydroxyapatite like crystals in the surface of the samples. (author)

Phosphate solubilization and multiple plant growth promoting ...

African Journals Online (AJOL)

Phosphate solubilizing efficiencies of the strains were analyzed using different insoluble phosphorus sources and the results show that most isolates released a substantial amount of soluble phosphate from tricalcium phosphate, rock phosphate and bone meal. Screening for multiple plant growth promoting attributes ...

Evaluation of intestinal phosphate binding to improve the safety profile of oral sodium phosphate bowel cleansing.

Directory of Open Access Journals (Sweden)

Stef Robijn

Full Text Available Prior to colonoscopy, bowel cleansing is performed for which frequently oral sodium phosphate (OSP is used. OSP results in significant hyperphosphatemia and cases of acute kidney injury (AKI referred to as acute phosphate nephropathy (APN; characterized by nephrocalcinosis are reported after OSP use, which led to a US-FDA warning. To improve the safety profile of OSP, it was evaluated whether the side-effects of OSP could be prevented with intestinal phosphate binders. Hereto a Wistar rat model of APN was developed. OSP administration (2 times 1.2 g phosphate by gavage with a 12h time interval induced bowel cleansing (severe diarrhea and significant hyperphosphatemia (21.79 ± 5.07 mg/dl 6h after the second OSP dose versus 8.44 ± 0.97 mg/dl at baseline. Concomitantly, serum PTH levels increased fivefold and FGF-23 levels showed a threefold increase, while serum calcium levels significantly decreased from 11.29 ± 0.53 mg/dl at baseline to 8.68 ± 0.79 mg/dl after OSP. OSP administration induced weaker NaPi-2a staining along the apical proximal tubular membrane. APN was induced: serum creatinine increased (1.5 times baseline and nephrocalcinosis developed (increased renal calcium and phosphate content and calcium phosphate deposits on Von Kossa stained kidney sections. Intestinal phosphate binding (lanthanum carbonate or aluminum hydroxide was not able to attenuate the OSP induced side-effects. In conclusion, a clinically relevant rat model of APN was developed. Animals showed increased serum phosphate levels similar to those reported in humans and developed APN. No evidence was found for an improved safety profile of OSP by using intestinal phosphate binders.

Phosphate and phosphate fertilizer sector: structure and future prospects. [Uranium recovery

Energy Technology Data Exchange (ETDEWEB)

Zenaidi, B

1981-12-01

A statement of the past evolution of this sector's structure is given. Various prospective studies which have been made are reviewed and lead to the precision of the phosphate requirement in the year 2000 which is between 200 and 250 Mt. Only a small section p. 696-697 is devoted to recovery of uranium contained in phosphate and prospects in this field are given.

Better prospects for phosphate production

Energy Technology Data Exchange (ETDEWEB)

1980-06-01

The extraction of uranium as a by product of phosphate production is discussed. Techniques being commercially developed are described. The trend towards the wet process, in which sulphuric acid is used to dissolve the phosphate, producing phosphoric acid, is also the preferred method for uranium recovery. Recovery from a wet process phosphoric acid stream, integrated with phosphate fertilizer manufacture, is becoming increasingly commercially viable for the production of yellow-cake.

The Oxygen Isotopic Composition of Phosphate: A Tracer for Phosphate Sources and Cycling

Energy Technology Data Exchange (ETDEWEB)

Mclaughlin, K. [Southern California Coastal Water Research Project, Costa Mesa, University of California, CA (United States); Young, M. B.; Paytan, A.; Kendall, C. [U.S. Geological Survey, University of California, CA (United States)

2013-05-15

Phosphorus (P) is a limiting macro-nutrient for primary productivity and anthropogenic P-loading to aquatic ecosystems is one of the leading causes of eutrophication in many ecosystems throughout the world. Because P has only one stable isotope, traditional isotope techniques are not possible for tracing sources and cycling of P in aquatic systems. However, much of the P in nature is bonded to four oxygen (O) atoms as orthophosphate (PO{sub 4}{sup 3-}). The P-O bonds in orthophosphate are strongly resistant to inorganic hydrolysis and do not exchange oxygen with water without biological mediation (enzyme-mediated recycling). Thus, the oxygen isotopic composition of dissolved inorganic phosphate ({delta}{sup 18}O{sub p}) may be used as a tracer for phosphate sources and cycling in aquatic ecosystems. Recently, several studies have been conducted utilizing {delta}{sup 18}O{sub p} as a tracer for phosphate sources and cycling in various aquatic environments. Specifically, work to date indicates that {delta}{sup 18}O{sub p} is useful for determining sources of phosphate to aquatic systems if these sources have unique isotopic signatures and phosphate cycling within the system is limited compared to input fluxes. In addition, because various processes imprint specific fractionation effects, the {delta}{sup 18}O{sub p} tracer can be utilized to determine the degree of phosphorous cycling and processing through the biomass. This chapter reviews several of these studies and discusses the potential to utilize the {delta}{sup 18}O{sub p} of phosphate in rivers and streams. (author)

Occurrence and functioning of phosphate solubilizing ...

African Journals Online (AJOL)

Occurrence and functioning of phosphate solubilizing microorganisms from oil palm tree ( Elaeis guineensis ) rhizosphere in Cameroon. ... While the use of soluble mineral phosphate fertilizers is the obvious best means to combat phosphate ... in order to improve agricultural production, using low inputs technology. Isolates ...

Enhanced activity and stability of L-arabinose isomerase by immobilization on aminopropyl glass.

Science.gov (United States)

Zhang, Ye-Wang; Jeya, Marimuthu; Lee, Jung-Kul

2011-03-01

Immobilization of Bacillus licheniformis L: -arabinose isomerase (BLAI) on aminopropyl glass modified with glutaraldehyde (4 mg protein g support⁻¹) was found to enhance the enzyme activity. The immobilization yield of BLAI was proportional to the quantity of amino groups on the surface of support. Reducing particle size increased the adsorption capacity (q(m)) and affinity (k(a)). The pH and temperature for immobilization were optimized to be pH 7.1 and 33 °C using response surface methodology (RSM). The immobilized enzyme was characterized and compared to the free enzyme. There is no change in optimal pH and temperature before and after immobilization. However, the immobilized BLAI enzyme achieved 145% of the activity of the free enzyme. Correspondingly, the catalytic efficiency (k(cat)/K(m)) was improved 1.47-fold after immobilization compared to the free enzyme. The thermal stability was improved 138-fold (t₁/₂) increased from 2 to 275 h) at 50 °C following immobilization.

The crystal structure of a multifunctional protein: phosphoglucose isomerase/autocrine motility factor/neuroleukin.

Science.gov (United States)

Sun, Y J; Chou, C C; Chen, W S; Wu, R T; Meng, M; Hsiao, C D

1999-05-11

Phosphoglucose isomerase (PGI) plays a central role in both the glycolysis and the gluconeogenesis pathways. We present here the complete crystal structure of PGI from Bacillus stearothermophilus at 2.3-A resolution. We show that PGI has cell-motility-stimulating activity on mouse colon cancer cells similar to that of endogenous autocrine motility factor (AMF). PGI can also enhance neurite outgrowth on neuronal progenitor cells similar to that observed for neuroleukin. The results confirm that PGI is neuroleukin and AMF. PGI has an open twisted alpha/beta structural motif consisting of two globular domains and two protruding parts. Based on this substrate-free structure, together with the previously published biological, biochemical, and modeling results, we postulate a possible substrate-binding site that is located within the domains' interface for PGI and AMF. In addition, the structure provides evidence suggesting that the top part of the large domain together with one of the protruding loops might participate in inducing the neurotrophic activity.

PHOSPHATE CRYSTALLURIA IN VARIOUS FORMS OF UROLITHIASIS AND POSSIBILITIES OF ITS PROGNOSTICATION IN PATIENTS WITH PHOSPHATE STONES

Directory of Open Access Journals (Sweden)

O. V. Konstantinova

2017-01-01

Full Text Available Purpose. Definition of types of crystalluria in various forms of urolithiasis and biochemical signs of phosphate crystals in the urine, while phosphate urolithiasis (infectious origin.Patients and methods. The study involved 144 patients with recurrent urolithiasis — 75 women and 69 men. Of these, 46 — diagnosed calculi with uric acid, 44 — calcium oxalate or mixed with a prevalence of calcium oxalate, in 54 — phosphate rocks (carbonate-apatite and/or struvite. The age of patients ranged from 21 to 74 years. 93 people have been under long-term, within 2–15 years, outpatient observation. The examination included the collection of anamnesis, general and microbiological analysis of urine, biochemical blood serum and urine on 10 indicators, reflecting renal function, state of the protein, water and electrolyte metabolism, uric acid metabolism, the chemical composition of the stone analysis.Results. It was found that in patients with calcium oxalate stones phosphaturia has been diagnosed in 2% of cases. And, along with calcium phosphate crystals they had oxalate crystals. In patients with phosphate urolithiasis phosphaturia observed in 96% of patients, in two patients (4% they determined except phosphates also oxalate salt in urine sediment. Patients with phosphate urolithiasis at occurrence of phosphate crystalluria have metabolic state changes: increased serum uric acid concentration from 0.322 ± 0.009 to 0.367 ± 0.018 mmol/l daily renal excretion of inorganic phosphate 23.94 ± 2.93 mmol/day to 32.12 ± 4.39 mmol/day, and reduced total calcium content in urine 6.61 ± 0.94 mmol/day to 3.37 ± 0.89 mmol/day. The results led to the following conclusion.Conclusion. Biochemical signs of occurrence of phosphate crystalluria in patients with stones of infectious origin can be: the approaching level of excretion in the urine of inorganic phosphates to 32,12 ± 4,39 mmol/day, serum uric acid concentration to 0,367 ± 0,018 mmol/l, and the

on association of trialkyl phosphates

International Nuclear Information System (INIS)

Petkovic, D.M.; Maksimovic, Z.B.

1976-01-01

The association constants of tri-n-butyl (TBP), tri-n-propyl (TPP) and triethyl phosphate (TEP) with chloroform, carbon tetrachloride and benzene were determined by dielectric constant, proton magnetic resonance and vapor pressure measurements. Correlation of the trialkyl phosphate-chloroform association constants, using the Hammett equation, showed their increase with the number of carbon atoms in the aliphatic radicals. The change of trialkyl phosphate reactivity with temperature was used to determine the thermodynamic quantities. (author)

Bio-treatment of phosphate from synthetic wastewater using ...

African Journals Online (AJOL)

In this study, the efficient phosphate utilizing isolates were used to remove phosphate from synthetic phosphate wastewater was tested using batch scale process. Hence the objective of the present study was to examine the efficiency of bacterial species individually for the removal of phosphate from synthetic phosphate ...

Infrared-spectroscopy analysis of zinc phosphate and nickel and manganese modified zinc phosphate coatings on electrogalvanized steel

International Nuclear Information System (INIS)

Fernandes, Kirlene Salgado; Alvarenga, Evandro de Azevedo; Lins, Vanessa de Freitas Cunha

2011-01-01

Hopeite-type phosphate coatings in which zinc is partially replaced by other metals like manganese and nickel are of great interest for the automotive and home appliance industries. Such industries use phosphate conversion coatings on galvanized steels in association with cataphoretic electro painting. Zinc phosphates modified with manganese and nickel are isomorphic with the hopeite, and the phase identification using X-ray diffraction is difficult. In this paper, the phosphate coatings are identified using the Fourier transform infrared spectroscopy (FTIR). (author)

Application of Calcium Phosphate Materials in Dentistry

Directory of Open Access Journals (Sweden)

Jabr S. Al-Sanabani

2013-01-01

Full Text Available Calcium phosphate materials are similar to bone in composition and in having bioactive and osteoconductive properties. Calcium phosphate materials in different forms, as cements, composites, and coatings, are used in many medical and dental applications. This paper reviews the applications of these materials in dentistry. It presents a brief history, dental applications, and methods for improving their mechanical properties. Notable research is highlighted regarding (1 application of calcium phosphate into various fields in dentistry; (2 improving mechanical properties of calcium phosphate; (3 biomimetic process and functionally graded materials. This paper deals with most common types of the calcium phosphate materials such as hydroxyapatite and tricalcium phosphate which are currently used in dental and medical fields.

Whole cell immobilization of refractory glucose isomerase using tris(hydroxymethyl)phosphine as crosslinker for preparation of high fructose corn syrup at elevated temperature.

Science.gov (United States)

Jia, Dong-Xu; Wang, Teng; Liu, Zi-Jian; Jin, Li-Qun; Li, Jia-Jia; Liao, Cheng-Jun; Chen, De-Shui; Zheng, Yu-Guo

2018-04-04

Glucose isomerase (GI) responsible for catalyzing the isomerization from d-glucose to d-fructose, was an important enzyme for producing high fructose corn syrup (HFCS). In a quest to prepare HFCS at elevated temperature and facilitate enzymatic recovery, an effective procedure for whole cell immobilization of refractory Thermus oshimai glucose isomerase (ToGI) onto Celite 545 using tris(hydroxymethyl)phosphine (THP) as crosslinker was established. The immobilized biocatalyst showed an activity of approximate 127.3 U/(g·immobilized product) via optimization in terms of cells loading, crosslinker concentration and crosslinking time. The pH optimum of the immobilized biocatalyst was displaced from pH 8.0 of native enzyme to neutral pH 7.0. Compared with conventional glutaraldehyde (GLU)-immobilized cells, it possessed the enhanced thermostability with 70.1% residual activity retaining after incubation at 90°C for 72 h. Moreover, the THP-immobilized biocatalyst exhibited superior operational stability, in which it retained 85.8% of initial activity after 15 batches of bioconversion at 85°C. This study paved a way for reducing catalysis cost for upscale preparation of HFCS with higher d-fructose concentration. Copyright © 2018 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Phosphate acquisition efficiency and phosphate starvation tolerance ...

Indian Academy of Sciences (India)

3Department of Genetics and Plant Breeding, College of Agriculture, Lembucherra, Tripura 799 ... vated in soil like red and lateritic or acid, with low soluble phosphate content. ..... activation of genes involved in the adaptation of Arabidopsis to.

Most consumed processed foods by patients on hemodialysis: Alert for phosphate-containing additives and the phosphate-to-protein ratio.

Science.gov (United States)

Watanabe, Marcela T; Araujo, Raphael M; Vogt, Barbara P; Barretti, Pasqual; Caramori, Jacqueline C T

2016-08-01

Hyperphosphatemia is common in patients with chronic kidney disease (CKD) stages IV and V because of decreased phosphorus excretion. Phosphatemia is closely related to dietary intake. Thus, a better understanding of sources of dietary phosphate consumption, absorption and restriction, particularly inorganic phosphate found in food additives, is key to prevent consequences of this complication. Our aims were to investigate the most commonly consumed processed foods by patients with CKD on hemodialysis, to analyze phosphate and protein content of these foods using chemical analysis and to compare these processed foods with fresh foods. We performed a cross-sectional descriptive analytical study using food frequency questionnaires to rank the most consumed industrialized foods and beverages. Total phosphate content was determined by metavanadate colorimetry, and nitrogen content was determined by the Kjeldahl method. Protein amounts were estimated from nitrogen content. The phosphate-to-protein ratio (mg/g) was then calculated. Processed meat protein and phosphate content were compared with the nutritional composition of fresh foods using the Brazilian Food Composition Table. Phosphate measurement results were compared with data from the Food Composition Table - Support for Nutritional Decisions. An α level of 5% was considered significant. Food frequency questionnaires were performed on 100 patients (mean age, 59 ± 14 years; 57% male). Phosphate additives were mentioned on 70% of the product labels analyzed. Proteins with phosphate-containing additives provided approximately twice as much phosphate per gram of protein compared with that of fresh foods (p processed foods are higher than those of fresh foods, as well as phosphate-to-protein ratio. A better understanding of phosphate content in foods, particularly processed foods, may contribute to better control of phosphatemia in patients with CKD. Copyright © 2016 European Society for Clinical Nutrition and

31P-Nuclear Magnetic Resonance Determination of Phosphate Compartmentation in Leaves of Reproductive Soybeans (Glycine max L.) as Affected by Phosphate Nutrition 1

Science.gov (United States)

Lauer, Michael J.; Blevins, Dale G.; Sierzputowska-Gracz, Hanna

1989-01-01

Most leaf phosphorus is remobilized to the seed during reproductive development in soybean. We determined, using 31P-NMR, the effect phosphorus remobilization has on vacuolar inorganic phosphate pool size in soybean (Glycine max [L.] Merr.) leaves with respect to phosphorus nutrition and plant development. Phosphate compartmentation between cytoplasmic and vacuolar pools was observed and followed in intact tissue grown hydroponically, at the R2, R4, and R6 growth stages. As phosphorus in the nutrient solution decreased from 0.45 to 0.05 millimolar, the vacuolar phosphate peak became less prominent relative to cytoplasmic phosphate and hexose monophosphate peaks. At a nutrient phosphate concentration of 0.05 millimolar, the vacuolar phosphate peak was not detectable. At higher levels of nutrient phosphate, as plants progressed from the R2 to the R6 growth stage, the vacuolar phosphate peak was the first to disappear, suggesting that storage phosphate was remobilized to a greater extent than metabolic phosphate. Under suboptimal phosphate nutrition (≤ 0.20 millimolar), the hexose monophosphate and cytoplasmic phosphate peaks declined earlier in reproductive development than when phosphate was present in optimal amounts. Under low phosphate concentrations (0.05 millimolar) cytoplasmic phosphate was greatly reduced. Carbon metabolism was coincidently disrupted under low phosphate nutrition as shown by the appearance of large, prominent starch grains in the leaves. Cytoplasmic phosphate, and leaf carbon metabolism dependent on it, are buffered by vacuolar phosphate until late stages of reproductive growth. Images Figure 4 PMID:16666705

Pentose phosphates in nucleoside interconversion and catabolism.

Science.gov (United States)

Tozzi, Maria G; Camici, Marcella; Mascia, Laura; Sgarrella, Francesco; Ipata, Piero L

2006-03-01

Ribose phosphates are either synthesized through the oxidative branch of the pentose phosphate pathway, or are supplied by nucleoside phosphorylases. The two main pentose phosphates, ribose-5-phosphate and ribose-1-phosphate, are readily interconverted by the action of phosphopentomutase. Ribose-5-phosphate is the direct precursor of 5-phosphoribosyl-1-pyrophosphate, for both de novo and 'salvage' synthesis of nucleotides. Phosphorolysis of deoxyribonucleosides is the main source of deoxyribose phosphates, which are interconvertible, through the action of phosphopentomutase. The pentose moiety of all nucleosides can serve as a carbon and energy source. During the past decade, extensive advances have been made in elucidating the pathways by which the pentose phosphates, arising from nucleoside phosphorolysis, are either recycled, without opening of their furanosidic ring, or catabolized as a carbon and energy source. We review herein the experimental knowledge on the molecular mechanisms by which (a) ribose-1-phosphate, produced by purine nucleoside phosphorylase acting catabolically, is either anabolized for pyrimidine salvage and 5-fluorouracil activation, with uridine phosphorylase acting anabolically, or recycled for nucleoside and base interconversion; (b) the nucleosides can be regarded, both in bacteria and in eukaryotic cells, as carriers of sugars, that are made available though the action of nucleoside phosphorylases. In bacteria, catabolism of nucleosides, when suitable carbon and energy sources are not available, is accomplished by a battery of nucleoside transporters and of inducible catabolic enzymes for purine and pyrimidine nucleosides and for pentose phosphates. In eukaryotic cells, the modulation of pentose phosphate production by nucleoside catabolism seems to be affected by developmental and physiological factors on enzyme levels.

Effect of combined gamma-irradiation and storage on biochemical changes in sweet potato

International Nuclear Information System (INIS)

Ajlouni, S.; Handy, M.K.

1992-01-01

Sucrose of uncured red jewel sweet potato increased from 3.8% to 10.7% after a combined treatment of a 300 Krad dose and 4 days storage at 24 C o post-irradiation (PI). Starch decreased from 16.8% to 6.1% after 16 days following a 500 Krad treatment. Phosphorylase, phosphoglucomutase and sucrose phosphate synthase enzyme specific activities increased 2.4-, 1.8- and 1.3-fold, respectively, after 3 days PI following 200 Krad exposures compared to nonirradiated roots. The beta-Amylase, phospho glucose isomerase and sucrose synthase specific activities increased 1.2-fold. Sucrose synthesis in the irradiated sweet potato was attributed to beta-amylase, phosphorylase, phosphoglucomutase, phospho glucose isomerase and sucrose synthase. (author). 28 refs., 3 figs., 2 tabs

Meal phosphate variability does not support fixed dose phosphate binder schedules for patients treated with peritoneal dialysis: a prospective cohort study.

Science.gov (United States)

Leung, Simon; McCormick, Brendan; Wagner, Jessica; Biyani, Mohan; Lavoie, Susan; Imtiaz, Rameez; Zimmerman, Deborah

2015-12-09

Removal of phosphate by peritoneal dialysis is insufficient to maintain normal serum phosphate levels such that most patients must take phosphate binders with their meals. However, phosphate 'counting' is complicated and many patients are simply prescribed a specific dose of phosphate binders with each meal. Therefore, our primary objective was to assess the variability in meal phosphate content to determine the appropriateness of this approach. In this prospective cohort study, adult patients with ESRD treated with peritoneal dialysis and prescribed phosphate binder therapy were eligible to participate. Participants were excluded from the study if they were unable to give consent, had hypercalcemia, were visually or hearing impaired or were expected to receive a renal transplant during the time of the study. After providing informed consent, patients kept a 3-day diet diary that included all foods and beverages consumed in addition to portion sizes. At the same time, patients documented the amount of phosphate binders taken with each meal. The phosphate content of the each meal was estimated using ESHA Food Processor SQL Software by a registered dietitian. Meal phosphate and binder variability were estimated by the Intra Class Correlation Coefficient (ICC) where 0 indicates maximal variability and 1 indicates no variability. Seventy-eight patients consented to participate in the study; 18 did not complete the study protocol. The patients were 60 (± 17) years, predominately male (38/60) and Caucasian (51/60). Diabetic nephropathy was the most common cause of end stage kidney disease. The daily phosphate intake including snacks ranged from 959 ± 249 to 1144 ± 362 mg. The phosphate ICC by meal: breakfast 0.63, lunch 0.16; supper 0.27. The phosphate binder ICC by meal: breakfast 0.68, lunch 0.73, supper 0.67. The standard prescription of a set number of phosphate binders with each meal is not supported by the data; patients do not appear to be adjusting their

Comparative study on in vitro biocompatibility of synthetic octacalcium phosphate and calcium phosphate ceramics used clinically.

Science.gov (United States)

Morimoto, Shinji; Anada, Takahisa; Honda, Yoshitomo; Suzuki, Osamu

2012-08-01

The present study was designed to investigate the extent to which calcium phosphate bone substitute materials, including osteoconductive octacalcium phosphate (OCP), display cytotoxic and inflammatory responses based on their dissolution in vitro. Hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) ceramics, which are clinically used, as well as dicalcium phosphate dihydrate (DCPD) and synthesized OCP were compared. The materials were well characterized by chemical analysis, x-ray diffraction and Fourier transform infrared spectroscopy. Calcium and phosphate ion concentrations and the pH of culture media after immersion of the materials were determined. The colony forming rate of Chinese hamster lung fibroblasts was estimated with extraction of the materials. Proliferation of bone marrow stromal ST-2 cells and inflammatory cytokine TNF-α production by THP-1 cells grown on the material-coated plates were examined. The materials had characteristics that corresponded to those reported. DCPD was shown to dissolve the most in the culture media, with a marked increase in phosphate ion concentration and a reduction in pH. ST-2 cells proliferated well on the materials, with the exception of DCPD, which markedly inhibited cellular growth. The colony forming capacity was the lowest on DCPD, while that of the other calcium phosphates was not altered. In contrast, TNF-α was not detected even in cells grown on DCPD, suggesting that calcium phosphate materials are essentially non-inflammatory, while the solubility of the materials can affect osteoblastic and fibroblastic cellular attachment. These results indicate that OCP is biocompatible, which is similar to the materials used clinically, such as HA. Therefore, OCP could be clinically used as a biocompatible bone substitute material.

Analyses of uranium in some phosphate commercial products

International Nuclear Information System (INIS)

Kamel, N.H.M.; Sohsah, M.; Mohammad, H.M.; Sadek, M.

2005-01-01

The raw materials used in manufacturing of phosphate fertilizer products were derived from rocks. Rocks contain a remarkable of natural radioactivity. Uranium and phosphorous were originally initiated at the same time of the initiated rocks. The purpose of this research is to investigate solubility of uranium phosphate species at the phosphate fertilizer samples, samples including; raw phosphate material, single super phosphates (SSP) granules and powdered, triple super phosphates (TSP) and phosphogypsum samples were obtained from Abu-Zabal factory in Egypt. Solubility of uranium phosphate species was estimated. It was found that, less than half of the uranium phosphate species are soluble in water. The soluble uranium may be enter into the food chains by plant. Therefore, restriction should be done in order to limit contamination of land and the public

Phosphate Reduction in Emulsified Meat Products: Impact of Phosphate Type and Dosage on Quality Characteristics.

Science.gov (United States)

Glorieux, Seline; Goemaere, Olivier; Steen, Liselot; Fraeye, Ilse

2017-09-01

Phosphate reduction is of important industrial relevance in the manufacturing of emulsified meat products because it may give rise to a healthier product. The effect of seven different phosphate types was tested on the physicochemical and quality characteristics to select the most promising phosphate type for further cooked sausage manufacturing. Next, phosphate mass fraction was gradually reduced. Tetrasodium di- or pyrophosphate (TSPP) and sodium tripolyphosphate (STPP) increased pH, reduced structural properties, resulted in the highest emulsion stability, lowest cooking loss and had little effect on hardness. Based on the viscoelastic properties, a minimum mass fraction of 0.06% TSPP was sufficient to obtain an acceptable quality product. Rheology proved to be a very useful tool to evaluate the quality of meat products, as it gives insight in the structure of the meat product and especially the functional properties of meat proteins. Based on the obtained results, it can be concluded that the current amount of phosphate added to emulsified meat products can be significantly reduced with minimal loss of product quality.

[Phosphate-solubilizing activity of aerobic methylobacteria].

Science.gov (United States)

Agafonova, N V; Kaparullina, E N; Doronina, N V; Trotsenko, Iu A

2014-01-01

Phosphate-solubilizing activity was found in 14 strains of plant-associated aerobic methylobacteria belonging to the genera Methylophilus, Methylobacillus, Methylovorus, Methylopila, Methylobacterium, Delftia, and Ancyclobacter. The growth of methylobacteria on medium with methanol as the carbon and energy source and insoluble tricalcium phosphate as the phosphorus source was accompanied by a decrease in pH due to the accumulation of up to 7 mM formic acid as a methanol oxidation intermediate and by release of 120-280 μM phosphate ions, which can be used by both bacteria and plants. Phosphate-solubilizing activity is a newly revealed role of methylobacteria in phytosymbiosis.

Isolation and identification of a phosphate solubilising fungus from soil of a phosphate mine in Chaluse, Iran

Directory of Open Access Journals (Sweden)

Raheleh Jamshidi

2016-07-01

Full Text Available Microbial solubilisation of phosphorus from insoluble phosphates is an environmental friendly and cost effective approach in sustainable soil management. Introducing the indigenous microorganisms to soil requires shorter adaptation period and causes fewer ecological distortions than exogenous microorganisms. This study was conducted to isolate and identify the indigenous fungi for phosphate solubilisation in Mazandaran, Iran. A potent phosphate solubilising fungus was isolated from an Iranian phosphate mine and selected for solubilisation of rock phosphate (RP. The identified fungus was characterised by calmodulin-based polymerase chain reaction method as Aspergillus tubingensis SANRU (Sari Agricultural Sciences and Natural Resources University. The phosphate solubilisation ability of the fungal strain was carried out in shake-flask leaching experiments containing various concentrations of RP (1%, 2%, 4%, or 8% w/v. The maximum P solubilisation rate of 347 mg/l was achieved at 1% of RP concentration on day 9. The regression analysis indicated that the P solubilised mainly through acidification. This study shows the possibility of using A. tubingensis SANRU for application in the management of P fertilisation.

Translocation of metal phosphate via the phosphate inorganic transport system of Escherichia coli

NARCIS (Netherlands)

van Veen, H.W; Abee, T.; Kortstee, G.J J; Konings, W.N; Zehnder, A.J B

1994-01-01

P-i transport via the phosphate inorganic transport system (Pit) of Escherichia coil was studied in natural and artificial membranes. P-i uptake via Pit is dependent on the presence of divalent cations, like Mg2+, Ca2+, Co2+, or Mn2+, which form a soluble, neutral metal phosphate (MeHPO(4)) complex.

Co-precipitation of phosphate and iron limits mitochondrial phosphate availability in Saccharomyces cerevisiae lacking the yeast frataxin homologue (YFH1).

Science.gov (United States)

Seguin, Alexandra; Santos, Renata; Pain, Debkumar; Dancis, Andrew; Camadro, Jean-Michel; Lesuisse, Emmanuel

2011-02-25

Saccharomyces cerevisiae cells lacking the yeast frataxin homologue (Δyfh1) accumulate iron in the mitochondria in the form of nanoparticles of ferric phosphate. The phosphate content of Δyfh1 mitochondria was higher than that of wild-type mitochondria, but the proportion of mitochondrial phosphate that was soluble was much lower in Δyfh1 cells. The rates of phosphate and iron uptake in vitro by isolated mitochondria were higher for Δyfh1 than wild-type mitochondria, and a significant proportion of the phosphate and iron rapidly became insoluble in the mitochondrial matrix, suggesting co-precipitation of these species after oxidation of iron by oxygen. Increasing the amount of phosphate in the medium decreased the amount of iron accumulated by Δyfh1 cells and improved their growth in an iron-dependent manner, and this effect was mostly transcriptional. Overexpressing the major mitochondrial phosphate carrier, MIR1, slightly increased the concentration of soluble mitochondrial phosphate and significantly improved various mitochondrial functions (cytochromes, [Fe-S] clusters, and respiration) in Δyfh1 cells. We conclude that in Δyfh1 cells, soluble phosphate is limiting, due to its co-precipitation with iron.

Uranium production from phosphates

International Nuclear Information System (INIS)

Ketzinel, Z.; Folkman, Y.

1979-05-01

According to estimates of the world's uranium consumption, exploitation of most rich sources is expected by the 1980's. Forecasts show that the rate of uranium consumption will increase towards the end of the century. It is therefore desirable to exploit poor sources not yet in use. In the near future, the most reasonable source for developing uranium is phosphate rock. Uranium reserves in phosphates are estimated at a few million tons. Production of uranium from phosphates is as a by-product of phosphate rock processing and phosphoric acid production; it will then be possible to save the costs incurred in crushing and dissolving the rock when calculating uranium production costs. Estimates show that the U.S. wastes about 3,000 tons of uranium per annum in phosphoric acid based fertilisers. Studies have also been carried out in France, Yugoslavia and India. In Israel, during the 1950's, a small plant was operated in Haifa by 'Chemical and Phosphates'. Uranium processes have also been developed by linking with the extraction processes at Arad. Currently there is almost no activity on this subject because there are no large phosphoric acid plants which would enable production to take place on a reasonable scale. Discussions are taking place about the installation of a plant for phosphoric acid production utilising the 'wet process', producing 200 to 250,000 tons P 2 O 5 per annum. It is necessary to combine these facilities with uranium production plant. (author)

Electrical properties of phosphate glasses

International Nuclear Information System (INIS)

Mogus-Milankovic, A; Santic, A; Reis, S T; Day, D E

2009-01-01

Investigation of the electrical properties of phosphate glasses where transition metal oxide such as iron oxide is the network former and network modifier is presented. Phosphate glasses containing iron are electronically conducting glasses where the polaronic conduction is due to the electron hopping from low to high iron valence state. The identification of structural defects caused by ion/polaron migration, the analysis of dipolar states and electrical conductivity in iron phosphate glasses containing various alkali and mixed alkali ions was performed on the basis of the impedance spectroscopy (IS). The changes in electrical conductivity from as-quenched phosphate glass to fully crystallized glass (glass-ceramics) by IS are analyzed. A change in the characteristic features of IS follows the changes in glass and crystallized glass network. Using IS, the contribution of glass matrix, crystallized grains and grain boundary to the total electrical conductivity for iron phosphate glasses was analyzed. It was shown that decrease in conductivity is caused by discontinuities in the conduction pathways as a result of the disruption of crystalline network where two or more crystalline phases are formed. Also, phosphate-based glasses offer a unique range of biomaterials, as they form direct chemical bonding with hard/soft tissue. The surface charges of bioactive glasses are recognized to be the most important factors in determining biological responses. The improved bioactivity of the bioactive glasses as a result of the effects of the surface charges generated by electrical polarization is discussed.

Hydrogen permeation resistant phosphate coatings

International Nuclear Information System (INIS)

McGuire, J.C.

1979-01-01

A method for reducing hydrogen diffusion through metal wherein the metal is coated with a phosphate-radical-containing, phosphate-glass-forming material on at least one surface thereof. The coating is then heated to at least 350 0 C to form a phosphate glass. This method is especially applicable to nuclear reactors to minimize tritium diffusion. The coating is preferably formed with a solution of phosphoric acid which may also contain compounds such as MnSO 4 , SiO 2 and Na 2 Cr 2 0 7 . (author)

Hydrogen permeation resistant phosphate coatings

International Nuclear Information System (INIS)

McGuire, J.C.

1979-01-01

A method for reducing hydrogen diffusion through metal is described. The metal is coated with a phosphate-radical-containing, phosphate-glass-forming material on at least one surface. The coating is then heated to at least 350 0 C to form a phosphate glass. This method is especially applicable to nuclear reactors to minimize tritium diffusion. The coating is preferably formed with a solution of phosphoric acid which may also contain compounds such as MnSO 4 , SiO 2 and Na 2 Cr 2 O 7 . (author)

Transfer of Some Major and Trace Elements From Phosphate Rock to Super-Phosphate Fertilizers

International Nuclear Information System (INIS)

El-Reefya, H.I.; Bin-Jaz, A.A.; Zaied, M.E.; Badran, H.M.; Badran, H.M.

2014-01-01

This study assesses the transfer of some major and trace elements from phosphate rock (PR) to single (SSP) and triple (TSP) superphosphate fertilizers. Samples from a fertilizer plant and local market were collected and analyzed using inductively coupled plasma spectrometer. Cluster analysis indicated that the inner-relationship among the concentration of the elements in PR, SSP, and TSP are different. Only one element (Mo) has concentration in SSP higher than phosphate rock. The production process of these two types of superphosphate leads to transfer higher portion of Mn, B, Cu, Mo, Sr, and V present in the phosphate rock to SSP than TSP. The potentially hazardous element Cd is also transmitted more to SSP than TSP, and Cr is equally transferred to both types. The mean elemental concentrations normalized to the percentage of P 2 O 5 demonstrate that for most elements they are the higher concentrations in SSP are linked to the phosphate contents

Phosphate vibrations as reporters of DNA hydration

Science.gov (United States)

Corcelli, Steven

The asymmetric phosphate stretch vibrational frequency is extraordinarily sensitive to its local solvent environment. Using density functional theory calculations on the model compound dimethyl phosphate, the asymmetric phosphate stretch vibrational frequency was found to shift linearly with the magnitude of an electric field along the symmetry axis of the PO2 moiety (i.e. the asymmetric phosphate stretch is an excellent linear vibrational Stark effect probe). With this linear relationship established, asymmetric phosphate stretch vibrational frequencies were computed during the course of a molecular dynamics simulation of fully hydrated DNA. Moreover, contributions to shifts in the frequencies from subpopulations of water molecules (e.g. backbone, minor groove, major groove, etc.) were calculated to reveal how phosphate vibrations report the onset of DNA hydration in experiments that vary the relative humidity of non-condensing (dry) DNA samples.

Sonochemical precipitation of amorphous uranium phosphates from trialkyl phosphate solutions and their thermal conversion to UP2O7

Czech Academy of Sciences Publication Activity Database

Doroshenko, I.; Žurková, J.; Moravec, Z.; Bezdička, Petr; Pinkas, J.

2015-01-01

Roč. 26, SEP (2015), s. 157-162 ISSN 1350-4177 Institutional support: RVO:61388980 Keywords : Uranium * Phosphates * Sonochemistry * Nuclear waste * Trimethyl phosphate * Triethyl phosphate Subject RIV: CA - Inorganic Chemistry Impact factor: 4.556, year: 2015

Cerebrospinal Fluid Phosphate in Delirium after Hip Fracture

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Ane-Victoria Idland

2017-09-01

Full Text Available Aims: Phosphate is essential for neuronal activity. We aimed to investigate whether delirium is associated with altered phosphate concentrations in cerebrospinal fluid (CSF and serum. Methods: Seventy-seven patients with hip fracture were assessed for delirium before and after acute surgery. Prefracture dementia was diagnosed by an expert panel. Phosphate was measured in CSF obtained immediately before spinal anesthesia (n = 77 and in serum (n = 47. CSF from 23 cognitively healthy elderly patients undergoing spinal anesthesia was also analyzed. Results: Hip fracture patients with prevalent delirium had higher CSF phosphate concentrations than those without delirium (median 0.63 vs. 0.55 mmol/L, p = 0.001. In analyses stratified on dementia status, this difference was only significant in patients with dementia. Serum phosphate was ∼1 mmol/L; there was no association between serum phosphate concentration and delirium status. CSF phosphate did not correlate with serum levels. Conclusion: Patients with delirium superimposed on dementia have elevated phosphate levels.

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.)

Iron phosphate glass containing simulated fast reactor waste: Characterization and comparison with pristine iron phosphate glass

International Nuclear Information System (INIS)

Joseph, Kitheri; Asuvathraman, R.; Venkata Krishnan, R.; Ravindran, T.R.; Govindaraj, R.; Govindan Kutty, K.V.; Vasudeva Rao, P.R.

2014-01-01

Detailed characterization was carried out on an iron phosphate glass waste form containing 20 wt.% of a simulated nuclear waste. High temperature viscosity measurement was carried out by the rotating spindle method. The Fe 3+ /Fe ratio and structure of this waste loaded iron phosphate glass was investigated using Mössbauer and Raman spectroscopy respectively. Specific heat measurement was carried out in the temperature range of 300–700 K using differential scanning calorimeter. Isoconversional kinetic analysis was employed to understand the crystallization behavior of the waste loaded iron phosphate glass. The glass forming ability and glass stability of the waste loaded glass were also evaluated. All the measured properties of the waste loaded glass were compared with the characteristics of pristine iron phosphate glass

Functional Role of the Disulfide Isomerase ERp57 in Axonal Regeneration.

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Valentina Castillo

Full Text Available ERp57 (also known as grp58 and PDIA3 is a protein disulfide isomerase that catalyzes disulfide bonds formation of glycoproteins as part of the calnexin and calreticulin cycle. ERp57 is markedly upregulated in most common neurodegenerative diseases downstream of the endoplasmic reticulum (ER stress response. Despite accumulating correlative evidence supporting a neuroprotective role of ERp57, the contribution of this foldase to the physiology of the nervous system remains unknown. Here we developed a transgenic mouse model that overexpresses ERp57 in the nervous system under the control of the prion promoter. We analyzed the susceptibility of ERp57 transgenic mice to undergo neurodegeneration. Unexpectedly, ERp57 overexpression did not affect dopaminergic neuron loss and striatal denervation after injection of a Parkinson's disease-inducing neurotoxin. In sharp contrast, ERp57 transgenic animals presented enhanced locomotor recovery after mechanical injury to the sciatic nerve. These protective effects were associated with enhanced myelin removal, macrophage infiltration and axonal regeneration. Our results suggest that ERp57 specifically contributes to peripheral nerve regeneration, whereas its activity is dispensable for the survival of a specific neuronal population of the central nervous system. These results demonstrate for the first time a functional role of a component of the ER proteostasis network in peripheral nerve regeneration.

Calcium phosphates for biomedical applications

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Maria Canillas

2017-05-01

Full Text Available The history of calcium phosphates in the medicine field starts in 1769 when the first evidence of its existence in the bone tissue is discovered. Since then, the interest for calcium phosphates has increased among the scientific community. Their study has been developed in parallel with new advances in materials sciences, medicine or tissue engineering areas. Bone tissue engineering is the field where calcium phosphates have had a great importance. While the first bioceramics are selected according to bioinert, biocompatibility and mechanical properties with the aim to replace bone tissue damaged, calcium phosphates open the way to the bone tissue regeneration challenge. Nowadays, they are present in the majority of commercial products directed to repair or regenerate damaged bone tissue. Finally, in the last few decades, they have been suggested and studied as drug delivering devices and as vehicles of DNA and RNA for the future generation therapies.

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)

Calcium phosphates for biomedical applications

Energy Technology Data Exchange (ETDEWEB)

Canillas, M.; Pena, P.; Aza, A.H. de; Rodriguez, M.A.

2017-07-01

The history of calcium phosphates in the medicine field starts in 1769 when the first evidence of its existence in the bone tissue is discovered. Since then, the interest for calcium phosphates has increased among the scientific community. Their study has been developed in parallel with new advances in materials sciences, medicine or tissue engineering areas. Bone tissue engineering is the field where calcium phosphates have had a great importance. While the first bioceramics are selected according to bioinert, biocompatibility and mechanical properties with the aim to replace bone tissue damaged, calcium phosphates open the way to the bone tissue regeneration challenge. Nowadays, they are present in the majority of commercial products directed to repair or regenerate damaged bone tissue. Finally, in the last few decades, they have been suggested and studied as drug delivering devices and as vehicles of DNA and RNA for the future generation therapies. (Author)

Conditions promoting and restraining agronomic effectiveness of water-insoluble phosphate sources, in particular phosphate rock (PR): I. Indices of phosphate rock use opportunity (PRUOIS) and of phosphate rock suitability for direct use (PRSIDU)

International Nuclear Information System (INIS)

Borlan, Z.; Gavriluta, I.; Soare, M.; Stefanescu, D.; Alexandrescu, A.

2002-01-01

Several issues of phosphate rock (PR) use are discussed in this paper. Maize for green fodder (Zea mays L) and ryegrass (Lolium multiflorum Lam.) were grown in 7 kg of dry soil and in small pots of 1.25 kg dry soil capacity, respectively, on several base unsaturated soils belonging to Hapludoll and Hapludalf soil groups. The amount of phosphate rock (PR) to apply was based on experimental data considering soil adsorbed acidity (Ah), humus content (H 2 ), cation exchange capacity (T), sum of exchangeable bases (SEB) and mobile (easily soluble) phosphate content (P A L) in the soil. The factors were combined in a rock phosphate use, opportunity index of the soil (PRUOIS): PRUOIS=(A h *H 2 *100)/SEB*10 0.0245*P AL Rock phosphate suitability for direct use was evaluated by means of the rate of PR-P dissolution (PRPRS) in a 0.6% ammonium heptamolybdate in 0.01M calcium chloride solution (ppm P) and by carbonate content (%CaCO 3 ) in PR. Both of these parameters combined provided a phosphate rock suitability index for direct use (PRSIDU): PRSIDU [ppmP/min]=PRPRS*(1-0.03*CaCO 3 ) Water insoluble P sources studied were PR from Kola-Russia, Morocco, Kneifiss-Siria, El Hassa-Jordan, Gafsa- Tunisia, North-Carolina (USA), and Arad-Israel. All PRs were compared with TSP applied at the same rate of P. Neither PRUOIS or PRSIDU considered separately could satisfactorily explain the variance of PR efficiency. An index obtained by multiplicative combination of PRUOIS x PRSIDU did correlate significantly with indices on the agronomic efficiency of PR. (author)

Impaired Phosphate Tolerance Revealed With an Acute Oral Challenge.

Science.gov (United States)

Turner, Mandy E; White, Christine A; Hopman, Wilma M; Ward, Emilie C; Jeronimo, Paul S; Adams, Michael A; Holden, Rachel M

2018-01-01

Elevated serum phosphate is consistently linked with cardiovascular disease (CVD) events and mortality in the setting of normal and impaired kidney function. However, serum phosphate does not often exceed the upper limit of normal until glomerular filtration rate (GFR) falls below 30 mL/min/m 2 . It was hypothesized that the response to an oral, bioavailable phosphate load will unmask impaired phosphate tolerance, a maladaptation not revealed by baseline serum phosphate concentrations. In this study, rats with varying kidney function as well as normo-phosphatemic human subjects, with inulin-measured GFR (13.2 to 128.3mL/min), received an oral phosphate load. Hormonal and urinary responses were evaluated over 2 hours. Results revealed that the more rapid elevation of serum phosphate was associated with subjects and rats with higher levels of kidney function, greater responsiveness to acute changes in parathyroid hormone (PTH), and significantly more urinary phosphate at 2 hours. In humans, increases in urinary phosphate to creatinine ratio did not correlate with baseline serum phosphate concentrations but did correlate strongly to early increase of serum phosphate. The blunted rise in serum phosphate in rats with CKD was not the result of altered absorption. This result suggests acute tissue deposition may be altered in the setting of kidney function impairment. Early recognition of impaired phosphate tolerance could translate to important interventions, such as dietary phosphate restriction or phosphate binders, being initiated at much higher levels of kidney function than is current practice. © 2017 American Society for Bone and Mineral Research. © 2017 American Society for Bone and Mineral Research.

Phosphate Reduction in Emulsifi ed Meat Products: Impact of Phosphate Type and Dosage on Quality Characteristics

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Seline Glorieux

2017-01-01

Full Text Available Phosphate reduction is of important industrial relevance in the manufacturing of emulsifi ed meat products because it may give rise to a healthier product. The eff ect of seven diff erent phosphate types was tested on the physicochemical and quality characteristics to select the most promising phosphate type for further cooked sausage manufacturing. Next, phosphate mass fraction was gradually reduced. Tetrasodium di- or pyrophosphate (TSPP and sodium tripolyphosphate (STPP increased pH, reduced structural properties, resulted in the highest emulsion stability, lowest cooking loss and had litt le eff ect on hardness. Based on the viscoelastic properties, a minimum mass fraction of 0.06 % TSPP was suffi cient to obtain an acceptable quality product. Rheology proved to be a very useful tool to evaluate the quality of meat products, as it gives insight in the structure of the meat product and especially the functional properties of meat proteins. Based on the obtained results, it can be concluded that the current amount of phosphate added to emulsifi ed meat products can be signifi cantly reduced with minimal loss of product quality.

A Role of a Newly Identified Isomerase From Yarrowia lipolytica in Erythritol Catabolism

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Aleksandra M. Mirończuk

2018-05-01

Full Text Available Erythritol is a natural sweetener produced by microorganisms as an osmoprotectant. It belongs to the group of polyols and it can be utilized by the oleaginous yeast Yarrowia lipolytica. Despite the recent identification of the transcription factor of erythritol utilization (EUF1, the metabolic pathway of erythritol catabolism remains unknown. In this study we identified a new gene, YALI0F01628g, involved in erythritol assimilation. In silico analysis showed that YALI0F01628g is a putative isomerase and it is localized in the same region as EUF1. qRT-PCR analysis of Y. lipolytica showed a significant increase in YALI0F01628g expression during growth on erythritol and after overexpression of EUF1. Moreover, the deletion strain ΔF01628 showed significantly impaired erythritol assimilation, whereas synthesis of erythritol remained unchanged. The results showed that YALI0F1628g is involved in erythritol assimilation; thus we named the gene EYI1. Moreover, we suggest the metabolic pathway of erythritol assimilation in yeast Y. lipolytica.

Biotemplate synthesis of monodispersed iron phosphate hollow microspheres

International Nuclear Information System (INIS)

Cao Feng; Li Dongxu

2010-01-01

Monodispersed iron phosphate hollow microspheres with a high degree of crystallization were prepared through a facile in situ deposition method using rape pollen grains as a biotemplate. The functional group on the surface of the pollen grains could adsorb Fe 3+ , which provided the nucleation sites for growth of iron phosphate nanoparticles. After being sintered at 600 deg. C for 10 h, the pollen grains were removed and iron phosphate hollow microspheres were obtained. A scanning electron microscope and x-ray diffraction were applied to characterize the morphology and crystalline structure of the pollen grains, iron phosphate-coated pollen grains and iron phosphate hollow microspheres. Differential scanning calorimetry and thermogravity analyses were performed to investigate the thermal behavior of the iron phosphate-coated pollen grains during the calcinations. Energy dispersive spectroscopy and Fourier transform infrared spectroscopy were utilized to investigate the interaction between the pollen grains and iron phosphate. The effect of the pollen wall on the surface morphology of these iron phosphate hollow microspheres was also proven in this work.

Biotemplate synthesis of monodispersed iron phosphate hollow microspheres

Energy Technology Data Exchange (ETDEWEB)

Cao Feng; Li Dongxu, E-mail: dongxuli@njut.edu.c [College of Materials Science and Engineering, Nanjing University of Technology, Jiangsu Nanjing 210009 (China)

2010-03-15

Monodispersed iron phosphate hollow microspheres with a high degree of crystallization were prepared through a facile in situ deposition method using rape pollen grains as a biotemplate. The functional group on the surface of the pollen grains could adsorb Fe{sup 3+}, which provided the nucleation sites for growth of iron phosphate nanoparticles. After being sintered at 600 deg. C for 10 h, the pollen grains were removed and iron phosphate hollow microspheres were obtained. A scanning electron microscope and x-ray diffraction were applied to characterize the morphology and crystalline structure of the pollen grains, iron phosphate-coated pollen grains and iron phosphate hollow microspheres. Differential scanning calorimetry and thermogravity analyses were performed to investigate the thermal behavior of the iron phosphate-coated pollen grains during the calcinations. Energy dispersive spectroscopy and Fourier transform infrared spectroscopy were utilized to investigate the interaction between the pollen grains and iron phosphate. The effect of the pollen wall on the surface morphology of these iron phosphate hollow microspheres was also proven in this work.

The Effect of Moderate Dietary Protein and Phosphate Restriction on Calcium-Phosphate Homeostasis in Healthy Older Cats.

Science.gov (United States)

Geddes, R F; Biourge, V; Chang, Y; Syme, H M; Elliott, J

2016-09-01

Dietary phosphate and protein restriction decreases plasma PTH and FGF-23 concentrations and improves survival time in azotemic cats, but has not been examined in cats that are not azotemic. Feeding a moderately protein- and phosphate-restricted diet decreases PTH and FGF-23 in healthy older cats and thereby slows progression to azotemic CKD. A total of 54 healthy, client-owned cats (≥ 9 years). Prospective double-blinded randomized placebo-controlled trial. Cats were assigned to test diet (protein 76 g/Mcal and phosphate 1.6 g/Mcal) or control diet (protein 86 g/Mcal and phosphate 2.6 g/Mcal) and monitored for 18 months. Changes in variables over time and effect of diet were assessed by linear mixed models. A total of 26 cats ate test diet and 28 cats ate control diet. There was a significant effect of diet on urinary fractional excretion of phosphate (P = 0.045), plasma PTH (P = 0.005), and ionized calcium concentrations (P = 0.018), but not plasma phosphate, FGF-23, or creatinine concentrations. Plasma PTH concentrations did not significantly change in cats fed the test diet (P = 0.62) but increased over time in cats fed the control diet (P = 0.001). There was no significant treatment effect of the test diet on development of azotemic CKD (3 of 26 (12%) test versus 3 of 28 (11%) control, odds ratio 1.09 (95% CI 0.13-8.94), P = 0.92). Feeding a moderately protein- and phosphate-restricted diet has effects on calcium-phosphate homeostasis in healthy older cats and is well tolerated. This might have an impact on renal function and could be useful in early chronic kidney disease. Copyright © 2016 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

Isolation of phosphatase-producing phosphate solubilizing bacteria from Loriya hot spring: Investigation of phosphate solubilizing in the presence of different parameters

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Maryam Parhamfar

2014-04-01

Full Text Available Introduction: Biofertilizers are the microorganisms that can convert useless nutrient to usable compounds. Unlike fertilizer, cost of biofertilizer production is low and doesn’t produce ecosystem pollution. Phosphate fertilizers can be replaced by phosphate biofertilizer to produce improvement. So, it is necessary to screen the climate-compatible phosphate solubilizing bacteria. Materials and methods: In this project samples were picked up from Loriya hot spring, which are located in Jiroft. Samples were incubated in PKV medium for 3 days. Screening of phosphate solubilizing bacteria was performed on the specific media, based on clear area diameter. The best bacterium was identified based on 16s rDNA gene. Phosphate solubilizing activity of this strain was considered in different carbon, nitrogen, phosphate and pH sources. Results: Sequence alignment and phylogenetic tree results show that B. sp. LOR033 is closely related to Bacillus licheniformis, with 97% homology. In addition, results show that maximum enzyme production was performed after 2 days that incubation pH was decreased simultaneously when the time was increased. Carbon sources investigation show that glucose is the most appropriate in enzyme production and phosphate releasing. Furthermore, results show that the optimum initial pH for phytase production was pH5.0. Different phosphate sources show that tricalcium phosphate has the suitable effect on enzyme activity in three days of incubation. Discussion and conclusion: Phosphatase enzyme production capacity, growth in acidic pH and phosphate solubilizing potential in different salt and phosphate sources show that this strain has considerable importance as biofertilizers.

Aqueous phosphate removal using nanoscale zero-valent iron

International Nuclear Information System (INIS)

Almeelbi, Talal; Bezbaruah, Achintya

2012-01-01

Nanoscale zero-valent iron (NZVI) particles have been used for the remediation of a wide variety of contaminants. NZVI particles have high reactivity because of high reactive surface area. In this study, NZVI slurry was successfully used for phosphate removal and recovery. Batch studies conducted using different concentrations of phosphate (1, 5, and 10 mg PO 4 3− -P/L with 400 mg NZVI/L) removed ∼96 to 100 % phosphate in 30 min. Efficacy of the NZVI in phosphate removal was found to 13.9 times higher than micro-ZVI (MZVI) particles with same NZVI and MZVI surface area concentrations used in batch reactors. Ionic strength, sulfate, nitrate, and humic substances present in the water affected in phosphate removal by NZVI but they may not have any practical significance in phosphate removal in the field. Phosphate recovery batch study indicated that better recovery is achieved at higher pH and it decreased with lowering of the pH of the aqueous solution. Maximum phosphate recovery of ∼78 % was achieved in 30 min at pH 12. The successful rapid removal of phosphate by NZVI from aqueous solution is expected to have great ramification for cleaning up nutrient rich waters.

Research and engineering assessment of biological solubilization of phosphate

Energy Technology Data Exchange (ETDEWEB)

Rogers, R.D.; McIlwain, M.E.; Losinski, S.J.; Taylor, D.D.

1993-03-01

This research and engineering assessment examined a microbial phosphate solubilization process as a method of recovering phosphate from phosphorus containing ore compared to the existing wet acid and electric arc methods. A total of 860 microbial isolates, collected from a range of natural environments were tested for their ability to solubilize phosphate from rock phosphate. A bacterium (Pseudomonas cepacia) was selected for extensive characterization and evaluation of the mechanism of phosphate solubilization and of process engineering parameters necessary to recover phosphate from rock phosphate. These studies found that concentration of hydrogen ion and production of organic acids arising from oxidation of the carbon source facilitated microbial solubilization of both pure chemical insoluble phosphate compounds and phosphate rock. Genetic studies found that phosphate solubilization was linked to an enzyme system (glucose dehydrogenase). Process-related studies found that a critical solids density of 1% by weight (ore to liquid) was necessary for optimal solubilization. An engineering analysis evaluated the cost and energy requirements for a 2 million ton per year sized plant, whose size was selected to be comparable to existing wet acid plants.

21 CFR 582.1781 - Sodium aluminum phosphate.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Sodium aluminum phosphate. 582.1781 Section 582.1781 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Additives § 582.1781 Sodium aluminum phosphate. (a) Product. Sodium aluminum phosphate. (b) Conditions of...

21 CFR 182.1781 - Sodium aluminum phosphate.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium aluminum phosphate. 182.1781 Section 182.1781 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Food Substances § 182.1781 Sodium aluminum phosphate. (a) Product. Sodium aluminum phosphate. (b...

Removal mechanism of phosphate from aqueous solution by fly ash.

Science.gov (United States)

Lu, S G; Bai, S Q; Zhu, L; Shan, H D

2009-01-15

This work studied the effectiveness of fly ash in removing phosphate from aqueous solution and its related removal mechanism. The adsorption and precipitation of phosphate by fly ash were investigated separately in order to evaluate their role in the removal of phosphate. Results showed that the removal of phosphate by fly ash was rapid. The removal percentage of phosphate in the first 5min reached 68-96% of the maximum removal of phosphate by fly ash. The removal processes of phosphate by fly ash included a fast and large removal representing precipitation, then a slower and longer removal due to adsorption. The adsorption of phosphate on fly ash could be described well by Freundlich isotherm equation. The pH and Ca2+ concentration of fly ash suspension were decreased with the addition of phosphate, which suggests that calcium phosphate precipitation is a major mechanism of the phosphate removal. Comparison of the relative contribution of the adsorption and precipitation to the total removal of phosphate by fly ash showed that the adsorption accounted for 30-34% of the total removal of phosphate, depending on the content of CaO in fly ash. XRD patterns of the fly ash before and after phosphate adsorption revealed that phosphate salt (CaHPO4 x 2H2O) was formed in the adsorption process. Therefore, the removal of phosphate by fly ash can be attributed to the formation of phosphate precipitation as a brushite and the adsorption on hydroxylated oxides. The results suggested that the use of fly ash could be a promising solution to the removal of phosphate in the wastewater treatment and pollution control.

Isolation and screening phosphate solubilizers from composts as biofertilizer

International Nuclear Information System (INIS)

Phua Choo Kwai Hoe; Khairuddin Abdul Rahim; Latiffah Norddin; Abdul Razak Ruslan

2006-01-01

Phosphate solubilizers are miroorganisms that able to solubilize insoluble inorganic phosphate compounds or hydrolyze organic phosphate to inorganic P. Therefore make the P to be available for plant and consequently enhance plant growth and yield. Recently, phosphate solubilizing microorganisms has been shown to play an important role in the biofertilizer industry. Fifty-one bacterial were isolated from eleven composts. Most of the phosphate solubilizers were isolated from natural farming composted compost and normal composting compost. This shows that both of these composts are more suitable to use for phosphate solubilizer isolation compare commercial composts. Fourteen of the isolates were found to be phosphate solubilizers. These isolates produced a clear zone on the phosphate agar plates, showing their potential as biofertilizer. AP3 was significantly produced the largest clear zone compared with other isolates. This indicates that isolate AP 3 could be a good phosphate solubilizer. Thus, their effectiveness in the greenhouse and field should be evaluated. (Author)

Ser46 phosphorylation and prolyl-isomerase Pin1-mediated isomerization of p53 are key events in p53-dependent apoptosis induced by mutant huntingtin.

Science.gov (United States)

Grison, Alice; Mantovani, Fiamma; Comel, Anna; Agostoni, Elena; Gustincich, Stefano; Persichetti, Francesca; Del Sal, Giannino

2011-11-01

Huntington disease (HD) is a neurodegenerative disorder caused by a CAG repeat expansion in the gene coding for huntingtin protein. Several mechanisms have been proposed by which mutant huntingtin (mHtt) may trigger striatal neurodegeneration, including mitochondrial dysfunction, oxidative stress, and apoptosis. Furthermore, mHtt induces DNA damage and activates a stress response. In this context, p53 plays a crucial role in mediating mHtt toxic effects. Here we have dissected the pathway of p53 activation by mHtt in human neuronal cells and in HD mice, with the aim of highlighting critical nodes that may be pharmacologically manipulated for therapeutic intervention. We demonstrate that expression of mHtt causes increased phosphorylation of p53 on Ser46, leading to its interaction with phosphorylation-dependent prolyl isomerase Pin1 and consequent dissociation from the apoptosis inhibitor iASPP, thereby inducing the expression of apoptotic target genes. Inhibition of Ser46 phosphorylation by targeting homeodomain-interacting protein kinase 2 (HIPK2), PKCδ, or ataxia telangiectasia mutated kinase, as well as inhibition of the prolyl isomerase Pin1, prevents mHtt-dependent apoptosis of neuronal cells. These results provide a rationale for the use of small-molecule inhibitors of stress-responsive protein kinases and Pin1 as a potential therapeutic strategy for HD treatment.

Uranium endowments in phosphate rock

Energy Technology Data Exchange (ETDEWEB)

Ulrich, Andrea E., E-mail: andrea.ulrich@env.ethz.ch [Institute for Environmental Decisions (IED), Natural and Social Science Interface, ETH Zurich Universitässtrasse 22, 8092 Zurich (Switzerland); Institute for Agricultural Sciences, Plant Nutrition, ETH Zurich, Eschikon 33, 8315 Lindau (Switzerland); Schnug, Ewald, E-mail: e.schnug@tu-braunschweig.de [Department of Life Sciences, Technical University of Braunschweig, Pockelsstraße 14, D-38106 Braunschweig (Germany); Prasser, Horst-Michael, E-mail: prasser@lke.mavt.ethz.ch [Institute of Energy Technology, Laboratory of Nuclear Energy Systems, ETH Zurich, Sonneggstrasse 3, 8092 Zurich (Switzerland); Frossard, Emmanuel, E-mail: emmanuel.frossard@usys.ethz.ch [Institute for Agricultural Sciences, Plant Nutrition, ETH Zurich, Eschikon 33, 8315 Lindau (Switzerland)

2014-04-01

This study seeks to identify and specify the components that make up the prospects of U recovery from phosphate rock. A systems approach is taken. The assessment includes i) reviewing past recovery experience and lessons learned; ii) identifying factors that determine recovery; and iii) establishing a contemporary evaluation of U endowments in phosphate rock reserves, as well as the available and recoverable amounts from phosphate rock and phosphoric acid production. We find that in the past, recovery did not fulfill its potential and that the breakup of the Soviet Union worsened then-favorable recovery market conditions in the 1990s. We find that an estimated 5.7 million tU may be recoverable from phosphate rock reserves. In 2010, the recoverable tU from phosphate rock and phosphoric acid production may have been 15,000 tU and 11,000 tU, respectively. This could have filled the world U supply-demand gap for nuclear energy production. The results suggest that the U.S., Morocco, Tunisia, and Russia would be particularly well-suited to recover U, taking infrastructural considerations into account. We demonstrate future research needs, as well as sustainability orientations. We conclude that in order to promote investment and production, it seems necessary to establish long-term contracts at guaranteed prices, ensuring profitability for phosphoric acid producers. - Highlights: • We identify components that underlie the recovery of uranium from phosphate rock. • We estimate that 11,000 tU may have been recoverable from phosphoric acid in 2010. • Recovery is a resource conservation and environmental pollution control strategy. • To ensure investment in recovery technology, profitability needs to be secured.

Uranium endowments in phosphate rock

International Nuclear Information System (INIS)

Ulrich, Andrea E.; Schnug, Ewald; Prasser, Horst-Michael; Frossard, Emmanuel

2014-01-01

This study seeks to identify and specify the components that make up the prospects of U recovery from phosphate rock. A systems approach is taken. The assessment includes i) reviewing past recovery experience and lessons learned; ii) identifying factors that determine recovery; and iii) establishing a contemporary evaluation of U endowments in phosphate rock reserves, as well as the available and recoverable amounts from phosphate rock and phosphoric acid production. We find that in the past, recovery did not fulfill its potential and that the breakup of the Soviet Union worsened then-favorable recovery market conditions in the 1990s. We find that an estimated 5.7 million tU may be recoverable from phosphate rock reserves. In 2010, the recoverable tU from phosphate rock and phosphoric acid production may have been 15,000 tU and 11,000 tU, respectively. This could have filled the world U supply-demand gap for nuclear energy production. The results suggest that the U.S., Morocco, Tunisia, and Russia would be particularly well-suited to recover U, taking infrastructural considerations into account. We demonstrate future research needs, as well as sustainability orientations. We conclude that in order to promote investment and production, it seems necessary to establish long-term contracts at guaranteed prices, ensuring profitability for phosphoric acid producers. - Highlights: • We identify components that underlie the recovery of uranium from phosphate rock. • We estimate that 11,000 tU may have been recoverable from phosphoric acid in 2010. • Recovery is a resource conservation and environmental pollution control strategy. • To ensure investment in recovery technology, profitability needs to be secured

Phosphate Salts

Science.gov (United States)

... body. They are involved in cell structure, energy transport and storage, vitamin function, and numerous other processes ... Phosphate-containing foods and beverages include cola, wine, beer, whole grain cereals, nuts, dairy products and some ...

Synthesis of amorphous acid iron phosphate nanoparticles

International Nuclear Information System (INIS)

Palacios, E.; Leret, P.; Fernández, J. F.; Aza, A. H. De; Rodríguez, M. A.

2012-01-01

A simple method to precipitate nanoparticles of iron phosphate with acid character has been developed in which the control of pH allows to obtain amorphous nanoparticles. The acid aging of the precipitated amorphous nanoparticles favored the P–O bond strength that contributes to the surface reordering, the surface roughness and the increase of the phosphate acid character. The thermal behavior of the acid iron phosphate nanoparticles has been also studied and the phosphate polymerization at 400 °C produces strong compacts of amorphous nanoparticles with interconnected porosity.

Are Polyphosphates or Phosphate Esters Prebiotic Reagents?

Science.gov (United States)

Keefe, Anthony D.; Miller, Stanley L.

1995-01-01

It is widely held that there was a phosphate compound in prebiotic chemistry that played the role of adenosine triphosphate and that the first living organisms had ribose-phosphate in the backbone of their genetic material. However, there are no known efficient prebiotic synthesis of high-energy phosphates or phosphate esters. We review the occurrence of phosphates in nature, the efficiency of the volcanic synthesis of P4O10, the efficiency of polyphosphate synthesis by heating phosphate minerals under geological conditions, and the use of high-energy organic compounds such as cyanamide or hydrogen cyanide. These are shown to be inefficient processes especially when the hydrolysis of the polyphosphates is taken into account. For example, if a whole atmosphere of methane or carbon monoxide were converted to cyanide which somehow synthesized polyphosphates quantitatively, the polyphosphate concentration in the ocean would still have been insignificant. We also attempted to find more efficient high-energy polymerizing agents by spark discharge syntheses, but without success. There may still be undiscovered robust prebiotic syntheses of polyphosphates, or mechanisms for concentrating them, but we conclude that phosphate esters may not have been constituents of the first genetic material. Phosphoanhydrides are also unlikely as prebiotic energy sources.

21 CFR 582.5697 - Riboflavin-5-phosphate.

Science.gov (United States)

2010-04-01

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

Structural Basis for Substrate Specificity in Phosphate Binding (beta/alpha)8-Barrels: D-Allulose 6-Phosphate 3-Epimerase from Escherichia coli K-12

Energy Technology Data Exchange (ETDEWEB)

Chan,K.; Fedorov, A.; Almo, S.; Gerlt, J.

2008-01-01

Enzymes that share the ({beta}/{alpha})8-barrel fold catalyze a diverse range of reactions. Many utilize phosphorylated substrates and share a conserved C-terminal ({beta}/a)2-quarter barrel subdomain that provides a binding motif for the dianionic phosphate group. We recently reported functional and structural studies of d-ribulose 5-phosphate 3-epimerase (RPE) from Streptococcus pyogenes that catalyzes the equilibration of the pentulose 5-phosphates d-ribulose 5-phosphate and d-xylulose 5-phosphate in the pentose phosphate pathway [J. Akana, A. A. Fedorov, E. Fedorov, W. R. P. Novack, P. C. Babbitt, S. C. Almo, and J. A. Gerlt (2006) Biochemistry 45, 2493-2503]. We now report functional and structural studies of d-allulose 6-phosphate 3-epimerase (ALSE) from Escherichia coli K-12 that catalyzes the equilibration of the hexulose 6-phosphates d-allulose 6-phosphate and d-fructose 6-phosphate in a catabolic pathway for d-allose. ALSE and RPE prefer their physiological substrates but are promiscuous for each other's substrate. The active sites (RPE complexed with d-xylitol 5-phosphate and ALSE complexed with d-glucitol 6-phosphate) are superimposable (as expected from their 39% sequence identity), with the exception of the phosphate binding motif. The loop following the eighth {beta}-strand in ALSE is one residue longer than the homologous loop in RPE, so the binding site for the hexulose 6-phosphate substrate/product in ALSE is elongated relative to that for the pentulose 5-phosphate substrate/product in RPE. We constructed three single-residue deletion mutants of the loop in ALSE, ?T196, ?S197 and ?G198, to investigate the structural bases for the differing substrate specificities; for each, the promiscuity is altered so that d-ribulose 5-phosphate is the preferred substrate. The changes in kcat/Km are dominated by changes in kcat, suggesting that substrate discrimination results from differential transition state stabilization. In both ALSE and RPE, the

Mineral phosphate solubilizing bacterial community in agro-ecosystem

African Journals Online (AJOL)

STORAGESEVER

2009-12-15

Dec 15, 2009 ... patterns. Four insoluble phosphate sources; purulia rock phosphate (PRP), mussourie rock phosphate. (MRP) ... community composition analysis (Garland, 1996a) and ..... the threshold level that enabled only a few species to.

[Phosphate solubilization of Aureobasidium pullulan F4 and its mechanism].

Science.gov (United States)

Wang, Dan; Zhan, Jing; Sun, Qing-Ye

2014-07-01

The Aureobasidium pullulans F4 was isolated from the rhizosphere of Hippochaete ramosissimum in Tongguanshan mine wasteland in Tongling City, Anhui Province. Liquid culture was conducted with four kinds of phosphorus sources, calcium phosphate, aluminum phosphate, ferric phosphate and rock phosphate to determine the pH, dissolved phosphorus, phosphorus in the bacteria and organic acid in the solution. The results showed that the phosphate solubilization by A. pullulans F4 varied with phosphorus sources, which decreased in order of aluminum phosphate > ferric phosphate, calcium phosphate > rock phosphate. The amounts of dissolved phosphorus in the different treatments were all higher than 200 mg x L(-1). The pH of the medium dropped immediately in 48 h, and the aluminum phosphate and ferric phosphate treatments showed a greater decrease in pH than the calcium phosphate and rock phosphate treatments. The organic acid synthesized by A. pullulans F4 included oxalic acid, citric acid and tartaric acid, and oxalic acid, among which oxalic acid was the dominated component. The phosphate dissolving capacity of A. pullulans F4 showed no significant correlation with organic acid, but significantly correlated with the pH. The available phosphorus was significantly improved with the combined application of A. pullulans F4 and glucose, suggesting A. pullulans F4 was a potent candidate for remediation of copper mine wastelands.

Hanford phosphate precipitation filtration process evaluation

International Nuclear Information System (INIS)

Walker, B.W.; McCabe, D.J.

1997-01-01

The purpose of this filter study was to evaluate cross-flow filtration as effective solid-liquid separation technology for treating Hanford wastes, outline operating conditions for equipment, examine the expected filter flow rates, and determine proper cleaning. A proposed Hanford waste pre-treatment process uses sodium hydroxide at high temperature to remove aluminum from sludge. This process also dissolves phosphates. Upon cooling to 40 degrees centigrade the phosphates form a Na7(PO4)2F9H2O precipitate which must be removed prior to further treatment. Filter studies were conducted with a phosphate slurry simulant to evaluate whether 0.5 micron cross-flow sintered metal Mott filters can separate the phosphate precipitate from the wash solutions. The simulant was recirculated through the filters at room temperature and filtration performance data was collected

Biosynthesis and characterization of layered iron phosphate

International Nuclear Information System (INIS)

Zhou Weijia; He Wen; Wang Meiting; Zhang Xudong; Yan Shunpu; Tian Xiuying; Sun Xianan; Han Xiuxiu; Li Peng

2008-01-01

Layered iron phosphate with uniform morphology has been synthesized by a precipitation method with yeast cells as a biosurfactant. The yeast cells are used to regulate the nucleation and growth of layered iron phosphate. The uniform layered structure is characterized by small-angle x-ray diffraction (SAXD), scanning electron microscopy (SEM) and atomic force microscopy (AFM) analyses. Fourier transform infrared spectroscopy (FT-IR) is used to analyze the chemical bond linkages in organic–inorganic hybrid iron phosphate. The likely synthetic mechanism of nucleation and oriented growth is discussed. The electrical conductivity of hybrid iron phosphate heat-treated at different temperatures is presented

Sorption of cesium on titanium and zirconium phosphates

International Nuclear Information System (INIS)

Lebedev, V.N.; Mel'nik, N.A.; Rudenko, A.V.

2003-01-01

Titanium and zirconium phosphates were prepared from mineral raw materials of the Kola Peninsula. Their capability to recover cesium cations from the model solutions and liquid radioactive waste (LRW) was studied. Titanium phosphate prepared from solutions formed by titanite breakdown demonstrates greater distribution coefficients of cesium as compared to zirconium phosphate. Titanium phosphate as a cheaper agent featuring greater sorption capacity was recommended for treatment of LRW to remove cesium [ru

PDILT, a divergent testis-specific protein disulfide isomerase with a non-classical SXXC motif that engages in disulfide-dependent interactions in the endoplasmic reticulum.

Science.gov (United States)

van Lith, Marcel; Hartigan, Nichola; Hatch, Jennifer; Benham, Adam M

2005-01-14

Protein disulfide isomerase (PDI) is the archetypal enzyme involved in the formation and reshuffling of disulfide bonds in the endoplasmic reticulum (ER). PDI achieves its redox function through two highly conserved thioredoxin domains, and PDI can also operate as an ER chaperone. The substrate specificities and the exact functions of most other PDI family proteins remain important unsolved questions in biology. Here, we characterize a new and striking member of the PDI family, which we have named protein disulfide isomerase-like protein of the testis (PDILT). PDILT is the first eukaryotic SXXC protein to be characterized in the ER. Our experiments have unveiled a novel, glycosylated PDI-like protein whose tissue-specific expression and unusual motifs have implications for the evolution, catalytic function, and substrate selection of thioredoxin family proteins. We show that PDILT is an ER resident glycoprotein that liaises with partner proteins in disulfide-dependent complexes within the testis. PDILT interacts with the oxidoreductase Ero1alpha, demonstrating that the N-terminal cysteine of the CXXC sequence is not required for binding of PDI family proteins to ER oxidoreductases. The expression of PDILT, in addition to PDI in the testis, suggests that PDILT performs a specialized chaperone function in testicular cells. PDILT is an unusual PDI relative that highlights the adaptability of chaperone and redox function in enzymes of the endoplasmic reticulum.

Method of decomposing treatment for radioactive organic phosphate wastes

International Nuclear Information System (INIS)

Uki, Kazuo; Ichihashi, Toshio; Hasegawa, Akira; Sato, Tatsuaki

1985-01-01

Purpose: To decompose the organic phosphoric-acid ester wastes containing radioactive material, which is produced from spent fuel reprocessing facilities, into inorganic materials using a simple device, under moderate conditions and at high decomposing ratio. Method: Radioactive organic phosphate wates are oxidatively decomposed by H 2 O 2 in an aqueous phosphoric-acid solution of metal phosphate salts. Copper phosphates are used as the metal phosphate salts and the decomposed solution of the radioactive organic phosphate wastes is used as the aqueous solution of the copper phosphate. The temperature used for the oxidizing decomposition ranges from 80 to 100 0 C. (Ikeda, J.)

Monte Carlo Simulations of Phosphate Polyhedron Connectivity in Glasses

Energy Technology Data Exchange (ETDEWEB)

ALAM,TODD M.

1999-12-21

Monte Carlo simulations of phosphate tetrahedron connectivity distributions in alkali and alkaline earth phosphate glasses are reported. By utilizing a discrete bond model, the distribution of next-nearest neighbor connectivities between phosphate polyhedron for random, alternating and clustering bonding scenarios was evaluated as a function of the relative bond energy difference. The simulated distributions are compared to experimentally observed connectivities reported for solid-state two-dimensional exchange and double-quantum NMR experiments of phosphate glasses. These Monte Carlo simulations demonstrate that the polyhedron connectivity is best described by a random distribution in lithium phosphate and calcium phosphate glasses.

The effect of different phosphate ion concentrations and ph of the phosphate buffer on lipase bioproduction by rhizopus oligosporus

International Nuclear Information System (INIS)

Haq, I.; Ali, S.; Awan, U.F.; Javed, W.; Mirza, S.

2005-01-01

In the present investigation, we report the effect of phosphate ion concentration and different ph of the phosphate buffer (as diluent) on lipase bioproduction by Rhizopus oligosporus. For this purpose, solid state fermentation was employed. Different agricultural by-products such as wheat bran, rice husk, almond meal, soybean meal and sunflower meal were used as substrate. The maximum lipase activity (72.60 U/g) was observed with the almond meal. Addition of phosphate ions (K/sub 2/HPO/sub 4/) influenced the lipase production. The ph of the phosphate buffer (7.0) was found to be effective for higher yield of lipase. (author)

In silico cloning and B/T cell epitope prediction of triosephosphate isomerase from Echinococcus granulosus.

Science.gov (United States)

Wang, Fen; Ye, Bin

2016-10-01

Cystic echinococcosis is a worldwide zoonosis caused by Echinococcus granulosus. Because the methods of diagnosis and treatment for cystic echinococcosis were limited, it is still necessary to screen target proteins for the development of new anti-hydatidosis vaccine. In this study, the triosephosphate isomerase gene of E. granulosus was in silico cloned. The B cell and T cell epitopes were predicted by bioinformatics methods. The cDNA sequence of EgTIM was composition of 1094 base pairs, with an open reading frame of 753 base pairs. The deduced amino acid sequences were composed of 250 amino acids. Five cross-reactive epitopes, locating on 21aa-35aa, 43aa-57aa, 94aa-107aa, 115-129aa, and 164aa-183aa, could be expected to serve as candidate epitopes in the development of vaccine against E. granulosus. These results could provide bases for gene cloning, recombinant expression, and the designation of anti-hydatidosis vaccine.

The EIS investigation of powder polyester coatings on phosphated low carbon steel: The effect of NaNO2 in the phosphating bath

International Nuclear Information System (INIS)

Jegdic, B.V.; Bajat, J.B.; Popic, J.P.; Stevanovic, S.I.; Miskovic-Stankovic, V.B.

2011-01-01

Highlights: → The effect of NaNO 2 on surface morphology of iron-phosphate coatings were determined. → Better corrosion stability of polyester coating on phosphated steel without NaNO 2 . → EIS results and microscopic examinations correlate well with adhesion measurements. - Abstract: The effect of different type of iron-phosphate coatings on corrosion stability and adhesion characteristic of top powder polyester coating on steel was investigated. Iron-phosphate coatings were deposited on steel in the novel phosphating bath with or without NaNO 2 as an accelerator. The corrosion stability of the powder polyester coating was evaluated by electrochemical impedance spectroscopy (EIS), adhesion by pull-off and NMP test, while surface morphology of phosphate coatings were investigated by atomic force microscopy (AFM). The adhesion and corrosion stability of powder polyester coatings were improved with pretreatment based on iron-phosphate coating deposited from NaNO 2 -free bath.

Radiological impact of use of phosphate fertilizers

International Nuclear Information System (INIS)

Shukla, V.K.; Chinnaesakki, S.; Sartandel, S.J.; Shanbhag, A.A.; Puranik, V.D.

2003-01-01

The paper describes the results of gamma spectrometric measurements of 238 U, 233 Th, 226 Ra and 40 K in rock phosphates and various types of phosphate fertilizers and by-products. The increase in soil natural radioactivity has been assessed for major Indian crops. No significant increase in soil natural radioactivity is expected due to the application of phosphate fertilizers for agricultural productions. (author)

Exploring plant factors for increasing phosphorus utilization from rock phosphates and native soil phosphates in acidic soils

International Nuclear Information System (INIS)

Feng Guanglin; Xiong Liming

2002-01-01

Six plant species with contrasting capacity in utilizing rock phosphates were compared with regard to their responses to phosphorus starvation in hydroponic cultures. Radish, buckwheat and oil rapeseed are known to have strong ability to use rock phosphates while ryegrass, wheat and sesbania are less efficient. Whereas other plants acidified their culture solution under P starvation (-P), radish plants make alkaline the solution. When neutralizing the pH of the solutions cultured with plants under either -P or + P conditions, solutions with P starved buckwheat, rapeseed, and radish had a higher ability to solubilize Al and Fe phosphates than did those cultured with sesbania, ryegrass and wheat. Characterization of organic ligands in the solutions identified that citrate and malate were the major organic anions exuded by rapeseed and radish. Besides citrate and malate, buckwheat exuded a large amount of tartrate under P starvation. In contrast, ryegrass, wheat and sesbania secreted only a limited amount of oxalic acid, regardless of P status. Changes in activities of phosphoenolpyruvate carboxylase, acid phosphatase, and nitrate reductase in these plants were also compared under P- sufficient or -deficient conditions. The results indicated that plant ability to use rock phosphates or soil phosphates is closely related to their responses toward P starvation. The diversity of P starvation responses was discussed in the context of co-evolution between plants and their environment. Approaches to use plant factors to enhance the effectiveness of rock phosphates were also discussed. (author)

The phosphate balance : current developments and future outlook

NARCIS (Netherlands)

Enk, van R.J.; Vee, van der G.; Acera, L.K.; Schuiling, R.; Ehlert, P.A.I.

2011-01-01

Phosphate is essential for agricultural production and therefore plays a key role in the global production of food and biofuels. There are no agricultural alternatives for phosphate, and a substantial fraction of our annual phosphate consumption is dispersed into the environment where it is largely

The phosphate balance : Current developments and future outlook

NARCIS (Netherlands)

Enk, R.J. van; Acera, L.K.; Schuiling, R.D.; Ehlert, P.; de Wilt, J.G.; van Haren, R.J.F.

2011-01-01

Phosphate is essential for agricultural production and therefore plays a key role in the global production of food and biofuels. There are no agricultural alternatives for phosphate, and a substantial fraction of our annual phosphate consumption is dispersed into the environment where it is largely

Engineering the l-Arabinose Isomerase from Enterococcus Faecium for d-Tagatose Synthesis.

Science.gov (United States)

de Sousa, Marylane; Manzo, Ricardo M; García, José L; Mammarella, Enrique J; Gonçalves, Luciana R B; Pessela, Benevides C

2017-12-06

l-Arabinose isomerase (EC 5.3.1.4) (l-AI) from Enterococcus faecium DBFIQ E36 was overproduced in Escherichia coli by designing a codon-optimized synthetic araA gene. Using this optimized gene, two N- and C-terminal His-tagged-l-AI proteins were produced. The cloning of the two chimeric genes into regulated expression vectors resulted in the production of high amounts of recombinant N -His-l-AI and C -His-l-AI in soluble and active forms. Both His-tagged enzymes were purified in a single step through metal-affinity chromatography and showed different kinetic and structural characteristics. Analytical ultracentrifugation revealed that C -His-l-AI was preferentially hexameric in solution, whereas N -His-l-AI was mainly monomeric. The specific activity of the N -His-l-AI at acidic pH was higher than that of C -His-l-AI and showed a maximum bioconversion yield of 26% at 50 °C for d-tagatose biosynthesis, with Km and Vmax parameters of 252 mM and 0.092 U mg -1 , respectively. However, C -His-l-AI was more active and stable at alkaline pH than N -His-l-AI. N -His-l-AI follows a Michaelis-Menten kinetic, whereas C -His-l-AI fitted to a sigmoidal saturation curve.

Radiological impacts of uranium recovery in the phosphate industry

International Nuclear Information System (INIS)

Ryan, M.T.

1981-01-01

This article characterizes the occupational and public radiological health impacts associated with phosphate mining and milling. These impacts are related to the phosphate industry's uranium production potential and are compared with those associated with conventional uranium mining and milling. The radiological impacts resulting from occupational and nonoccupational exposures are assessed. Occupational exposures in phosphate facilities are compared to background exposures and radiological population dose assessments, which characterize important radionuclides and exposure pathways. The following conclusions were reached: (1) public consequences of phosphate mining will occur whether or not uranium is recovered as a by-product, (2) radiological consequences of phosphate mining may be comparable to those associated with uranium mining and milling per unit uranium production, (3) radiological impacts via surface waterways and crops fertilized with uranium-bearing phosphates are of minor consequence, and (4) major radiological public health problems associated with phosphate mining are related to radon and radon progeny exposures in structures built on reclaimed lands or with phosphate mining residues, although the magnitudes of these impacts are difficult to evaluate with current data

Physico-chemical characterization of Ogun and Sokoto phosphate ...

African Journals Online (AJOL)

Gypsum, calcite and lime were associated with both rock phosphates indicating their liming potential in the soil. ORP was more soluble in water, probably because it ... fertilizers and direct application in crop production. Keywords: Phosphorus, apatite, crop production, fertilizer, Ogun rock phosphate, Sokoto rock phosphate ...

Fourier transform Raman spectroscopy of synthetic and biological calcium phosphates.

Science.gov (United States)

Sauer, G R; Zunic, W B; Durig, J R; Wuthier, R E

1994-05-01

Fourier-transform (FT) Raman spectroscopy was used to characterize the organic and mineral components of biological and synthetic calcium phosphate minerals. Raman spectroscopy provides information on biological minerals that is complimentary to more widely used infrared methodologies as some infrared-inactive vibrational modes are Raman-active. The application of FT-Raman technology has, for the first time, enabled the problems of high sample fluorescence and low signal-to-noise that are inherent in calcified tissues to be overcome. Raman spectra of calcium phosphates are dominated by a very strong band near 960 cm-1 that arises from the symmetric stretching mode (v1) of the phosphate group. Other Raman-active phosphate vibrational bands are seen at approximately 1075 (v3), 590 (v4), and 435 cm-1 (v2). Minerals containing acidic phosphate groups show additional vibrational modes. The different calcium phosphate mineral phases can be distinguished from one another by the relative positions and shapes of these bands in the Raman spectra. FT-Raman spectra of nascent, nonmineralized matrix vesicles (MV) show a distinct absence of the phosphate v1 band even though these structures are rich in calcium and phosphate. Similar results were seen with milk casein and synthetic Ca-phosphatidyl-serine-PO4 complexes. Hence, the phosphate and/or acidic phosphate ions in these noncrystalline biological calcium phosphates is in a molecular environment that differs from that in synthetic amorphous calcium phosphate. In MV, the first distinct mineral phase to form contained acidic phosphate bands similar to those seen in octacalcium phosphate. The mineral phase present in fully mineralized MV was much more apatitic, resembling that found in bones and teeth.(ABSTRACT TRUNCATED AT 250 WORDS)

Bioconversion of D-galactose to D-tagatose: continuous packed bed reaction with an immobilized thermostable L-arabinose isomerase and efficient purification by selective microbial degradation.

Science.gov (United States)

Liang, Min; Chen, Min; Liu, Xinying; Zhai, Yafei; Liu, Xian-wei; Zhang, Houcheng; Xiao, Min; Wang, Peng

2012-02-01

The continuous enzymatic conversion of D-galactose to D-tagatose with an immobilized thermostable L-arabinose isomerase in packed-bed reactor and a novel method for D-tagatose purification were studied. L-arabinose isomerase from Thermoanaerobacter mathranii (TMAI) was recombinantly overexpressed and immobilized in calcium alginate. The effects of pH and temperature on D-tagatose production reaction catalyzed by free and immobilized TMAI were investigated. The optimal condition for free enzyme was pH 8.0, 60°C, 5 mM MnCl(2). However, that for immobilized enzyme was pH 7.5, 75°C, 5 mM MnCl(2). In addition, the catalytic activity of immobilized enzyme at high temperature and low pH was significantly improved compared with free enzyme. The optimum reaction yield with immobilized TMAI increased by four percentage points to 43.9% compared with that of free TMAI. The highest productivity of 10 g/L h was achieved with the yield of 23.3%. Continuous production was performed at 70°C; after 168 h, the reaction yield was still above 30%. The resultant syrup was then incubated with Saccharomyces cerevisiae L1 cells. The selective degradation of D-galactose was achieved, obtaining D-tagatose with the purity above 95%. The established production and separation methods further potentiate the industrial production of D-tagatose via bioconversion and biopurification processes.

Phosphate recycling in the phosphorus industry

NARCIS (Netherlands)

Schipper, W.J.; Klapwijk, A.; Potjer, B.; Rulkens, W.H.; Temmink, B.G.; Kiestra, F.D.G.; Lijmbach, A.C.M.

2004-01-01

The article describes the potential and limitations for recovery of phosphate from secondary materials in the production process for white phosphorus. This thermal process involves the feeding of phosphate rock, cokes and pebbles to a furnace. The reducing conditions in the furnace promote the

Standard characterization of phosphate rock samples from the FAO/IAEA phosphate project

International Nuclear Information System (INIS)

Binh, Truong; Zapata, F.

2002-01-01

Phosphate rocks (PR) are phosphate-bearing minerals that vary widely in their inherent characteristics and consequently their agronomic potential. In the framework of a FAO/IAEA networked research project, the evaluation of the agronomic effectiveness of natural and modified PR products under a variety of soil climate and crop management conditions was carried out. The characterization of phosphate rocks is the first and essential step in evaluating their suitability for direct application. If several PR sources are utilized, standardized methods should be used for comparison purposes to determine their agronomic potential. This paper describes the standard characterization of phosphate rock products utilized in the project, in particular the mineralogical and crystallographic analyses, physical analyses, chemical composition and solubility in conventional reagents. A total of 28 phosphate rock samples from 15 countries were collected and analyzed in specialized laboratories. The data on mineralogy, chemical composition and solubility in conventional reagents are closely interrelated. An arbitrary classification of the reactivity of the PR samples was made based on the solubility indices in conventional reagents. On another hand, the results of the crystallographic parameters, calculated indices of absolute solubility, specific surface and porosity reflect the variability of the physical state and the sample pre-conditioning treatment of the analyzed products. A proper characterization of phosphate rock samples should provide the maximum of basic information that can be obtained in a cost-effective manner in normal chemical laboratories. Based on the results of this characterization, the following determinations are recommended: a description of the sample, major elemental (total P, Ca, Mg) composition, solubility in conventional reagents (neutral ammonium citrate, citric and formic acid) and particle size analysis. The classification of PR samples for direct

Heterologous expression and characterization of Bacillus coagulans L-arabinose isomerase.

Science.gov (United States)

Zhou, Xingding; Wu, Jin Chuan

2012-05-01

Bacillus coagulans has been of great commercial interest over the past decade owing to its strong ability of producing optical pure L: -lactic acid from both hexose and pentose sugars including L: -arabinose with high yield, titer and productivity under thermophilic conditions. The L: -arabinose isomerase (L-AI) from Bacillus coagulans was heterologously over-expressed in Escherichia coli. The open reading frame of the L-AI has 1,422 nucleotides encoding a protein with 474 amino acid residues. The recombinant L-AI was purified to homogeneity by one-step His-tag affinity chromatography. The molecular mass of the enzyme was estimated to be 56 kDa by SDS-PAGE. The enzyme was most active at 70°C and pH 7.0. The metal ion Mn(2+) was shown to be the best activator for enzymatic activity and thermostability. The enzyme showed higher activity at acidic pH than at alkaline pH. The kinetic studies showed that the K (m), V (max) and k (cat)/K (m) for the conversion of L: -arabinose were 106 mM, 84 U/mg and 34.5 mM(-1)min(-1), respectively. The equilibrium ratio of L: -arabinose to L: -ribulose was 78:22 under optimal conditions. L: -ribulose (97 g/L) was obtained from 500 g/l of L: -arabinose catalyzed by the enzyme (8.3 U/mL) under the optimal conditions within 1.5 h, giving at a substrate conversion of 19.4% and a production rate of 65 g L(-1) h(-1).

Radio phosphorus kinetics in the blood of sheep supplemented with dicalcium phosphate, mono ammonium phosphate, triple superphosphate and Tapira rock phosphate

International Nuclear Information System (INIS)

Abdalla, A.L.

1992-01-01

With the aim to study the kinetics of radio phosphorus ( 32 P) in the blood of animals supplemented with dicalcium phosphate (BIC), mono ammonium phosphate (MAP), triple superphosphate (SPT) and Tapira rock phosphate (TAP), 32 male sheep were kept in metabolic cages at the Animal Science Section / CENA - USP. Plasma was obtained by centrifugation and the specific activity, rate of disappearance and half life of 32 P in plasma were determined. In the red blood cells were determined the uptake rate of the radioisotope, the rate of disappearance and half life of 32 P up taken. It was observed a statistical significant difference (p 32 P in the plasma and erythrocytes. The specific activity and half life of 32 P in the plasma were statistically different (p<0,10) among sheep receiving the different phosphorus sources; the same was observed in respect to the red blood cells. It was concluded that the supplemented phosphorus source given in the diet of sheep may affect the kinetics of the radio phosphorus in the blood after been intravenously injected. (author)

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

Vanadate influence on metabolism of sugar phosphates in fungus Phycomyces blakesleeanus.

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Milan Žižić

Full Text Available The biological and chemical basis of vanadium action in fungi is relatively poorly understood. In the present study, we investigate the influence of vanadate (V5+ on phosphate metabolism of Phycomyces blakesleeanus. Addition of V5+ caused increase of sugar phosphates signal intensities in 31P NMR spectra in vivo. HPLC analysis of mycelial phosphate extracts demonstrated increased concentrations of glucose 6 phosphate, fructose 6 phosphate, fructose 1, 6 phosphate and glucose 1 phosphate after V5+ treatment. Influence of V5+ on the levels of fructose 2, 6 phosphate, glucosamine 6 phosphate and glucose 1, 6 phosphate (HPLC, and polyphosphates, UDPG and ATP (31P NMR was also established. Increase of sugar phosphates content was not observed after addition of vanadyl (V4+, indicating that only vanadate influences its metabolism. Obtained results from in vivo experiments indicate catalytic/inhibitory vanadate action on enzymes involved in reactions of glycolysis and glycogenesis i.e., phosphoglucomutase, phosphofructokinase and glycogen phosphorylase in filamentous fungi.

Issues of natural radioactivity in phosphates

International Nuclear Information System (INIS)

Schnug, E.; Haneklaus, S.; Schnier, C.; Scholten, L.C.

1996-01-01

The fertilization of phosphorus (P) fertilizers is essential in agricultural production, but phosphates contain in dependence on their origin different amounts of trace elements. The problem of cadmium (Cd) loads and other heavy metals is well known. However, only a limited number of investigations examined the contamination of phosphates with the two heaviest metals, uranium (U) and thorium (Th), which are radioactive. Also potassium (K) is lightly radioactive. Measurements are done n the radioactivity content of phosphates, P fertilizers and soils. The radiation doses to workers and public as well as possible contamination of soils from phosphate rock or fertilizer caused by these elements or their daughter products is of interest with regard to radiation protection. The use of P fertilizers is necessary for a sustainable agriculture, but it involves radioactive contamination of soils. The consequences of the use of P fertilizers is discussed, also with regard to existing and proposed legislation. 11 refs., 2 figs., 7 tabs

A phosphate-starvation-inducible outermembrane protein of Pseudomonas fluorescens Ag1 as an immunological phosphate-starvation marker

DEFF Research Database (Denmark)

Leopold, Kristine; Jacobsen, Susanne; Nybroe, Ole

1997-01-01

A phosphate-starvation-inducible outer-membrane protein of Pseudomonas fluorescens Ag1, expressed at phosphate concentrations below0.08-0.13 mM, was purified and characterized. The purification method involved separation of outer-membrane proteins by SDS-PAGE andextraction of the protein from...... nitrocellulose or PVDF membranes after electrotransfer of proteins to the membranes. The N-terminal amino acidsequence of the purified protein, called Psi1, did not show homology to any known proteins, and in contrast to the phosphate-specific porin OprP ofP. aeruginosa its mobility in SDS-PAGE was not affected...

Isolation of phosphate solubiliser fungi from Araza rhizosphere

International Nuclear Information System (INIS)

Vera, Diana Fernanda; Perez, Hernando; Valencia Hernando

2002-01-01

Araza is an eatable plant, original from the Amazon region, which has been described as a promising species for commercialization (Quevedo 1995). This plant has high productivity even in low content phosphate soil but the presence of phosphate solubilizing microorganisms may contribute to increase this element availability. In this study we report the isolation and characterization of solubilizing fungi processed using the soil washing method, from soil samples were araza is cultivated at two regions in Guaviare, Colombia. Eighteen isolates of fungi capable of solubilizing phosphate were obtained from 2 different sources. The most important species that solubilized phosphate from calcium were Trichoderma aureoviride, Aspergillus aculeatus, Trichoderma strain 1 y Trichoderma strain 2 and for phosphate from iron: Aspergillus oryzae, Paecilomyces strain 3, Gongronella butleri and Fusarium oxysporum

Dielectric aluminium phosphate thin films. Couches minces dielectriques de phosphate d'aluminium

Energy Technology Data Exchange (ETDEWEB)

Daviero, S. (Lab. Physicochimie des Materiaux Solides, 34 - Montpellier (France)); Avinens, C. (Lab. Physicochimie des Materiaux Solides, 34 - Montpellier (France)); Ibanez, A. (Lab. Physicochimie des Materiaux Solides, 34 - Montpellier (France)); Giuntini, J.C. (Lab. Physicochimie des Materiaux Solides, 34 -Montpellier (France)); Philippot, E. (Lab. Physicochimie des Materiaux Solides, 34 - Montpellier (France))

1993-04-01

Aluminium phosphate thin films on silicium substrate have been carried out from tributylphosphate and aluminium acetylacetonate precursors in solution through the ''pyrosol'' process. It can be observed a large range of chemical analysis in terms of experimental conditions. These thin films have been characterized by X-ray diffraction and infrared spectrometry. Their electrical characteristics, defined from direct current and alternative current measurements, are quite different to those of the crystallized phosphate and can be explained by P-O and Al-O ''dangling bond'' existence. (orig.).

Phosphate recycling in the phosphorus industry

NARCIS (Netherlands)

Schipper, W.J.; Klapwijk, A.; Potjer, A.; Rulkens, W.H.; Temmink, B.G.; Kiestra, F.D.G.; Lijmbach, A.C.M.

2001-01-01

The feasibility of phosphate recycling in the white phosphorus production process is discussed. Several types of materials may be recycled, provided they are dry inorganic materials, low in iron, copper and zinc. Sewage sludge ash may be used if no iron is used for phosphate precipitation in the

Application of Potential Phosphate-Solubilizing Bacteria and Organic Acids on Phosphate Solubilization from Phosphate Rock in Aerobic Rice

Directory of Open Access Journals (Sweden)

Qurban Ali Panhwar

2013-01-01

Full Text Available A study was conducted at Universiti Putra Malaysia to determine the effect of phosphate-solubilizing bacteria (PSB and organic acids (oxalic & malic on phosphate (P solubilization from phosphate rock (PR and growth of aerobic rice. Four rates of each organic acid (0, 10, 20, and 30 mM, and PSB strain (Bacillus sp. were applied to aerobic rice. Total bacterial populations, amount of P solubilization, P uptake, soil pH, and root morphology were determined. The results of the study showed significantly high P solubilization in PSB with organic acid treatments. Among the two organic acids, oxalic acid was found more effective compared to malic acid. Application of oxalic acid at 20 mM along with PSB16 significantly increased soluble soil P (28.39 mg kg−1, plant P uptake (0.78 P pot−1, and plant biomass (33.26 mg. Addition of organic acids with PSB and PR had no influence on soil pH during the planting period. A higher bacterial population was found in rhizosphere (8.78 log10 cfu g−1 compared to the nonrhizosphere and endosphere regions. The application of organic acids along with PSB enhanced soluble P in the soil solution, improved root growth, and increased plant biomass of aerobic rice seedlings without affecting soil pH.

Effectiveness and cost-efficiency of phosphate binders in hemodialysis

Directory of Open Access Journals (Sweden)

Zsifkovits, Johannes

2009-06-01

Full Text Available Health political background: In 2006, the prevalence of chronic renal insufficiency in Germany was 91,718, of which 66,508 patients were on dialysis. The tendency is clearly growing. Scientific background: Chronic renal insufficiency results in a disturbance of the mineral balance. It leads to hyperphosphataemia, which is the strongest independent risk factor for mortality in renal patients. Usually, a reduction in the phosphate intake through nutrition and the amount of phosphate filtered out during dialysis are not sufficient to reduce the serum phosphate values to the recommended value. Therefore, phosphate binders are used to bind ingested phosphate in the digestive tract in order to lower the phosphate concentration in the serum. Four different groups of phosphate binders are available: calcium- and aluminium salts are the traditional therapies. Sevelamer and Lanthanum are recent developments on the market. In varying doses, all phosphate binders are able to effectively lower phosphate concentrations. However, drug therapies have achieved recommended phosphate levels in only 50 percent of patients during the last years. Research questions: How effective and efficient are the different phosphate binders in chronic renal insufficient patients? Methods: The systematic literature search yielded 1,251 abstracts. Following a two-part selection process with predefined criteria 18 publications were included in the assessment. Results: All studies evaluated conclude that serum phosphate, serum calcium and intact parathyroid hormone can be controlled effectively with all phosphate binders. Only the number of episodes of hypercalcaemia is higher when using calcium-containing phosphatebinders compared to Sevelamer and Lanthanum. Regarding the mortality rate, the cardiovascular artery calcification and bone metabolism no definite conclusions can be drawn. In any case, the amount of calcification at study start seems to be crucial for the further

Functional and structural studies of the disulfide isomerase DsbC from the plant pathogen Xylella fastidiosa reveals a redox-dependent oligomeric modulation in vitro.

Science.gov (United States)

Santos, Clelton A; Toledo, Marcelo A S; Trivella, Daniela B B; Beloti, Lilian L; Schneider, Dilaine R S; Saraiva, Antonio M; Crucello, Aline; Azzoni, Adriano R; Souza, Alessandra A; Aparicio, Ricardo; Souza, Anete P

2012-10-01

Xylella fastidiosa is a Gram-negative bacterium that grows as a biofilm inside the xylem vessels of susceptible plants and causes several economically relevant crop diseases. In the present study, we report the functional and low-resolution structural characterization of the X. fastidiosa disulfide isomerase DsbC (XfDsbC). DsbC is part of the disulfide bond reduction/isomerization pathway in the bacterial periplasm and plays an important role in oxidative protein folding. In the present study, we demonstrate the presence of XfDsbC during different stages of X. fastidiosa biofilm development. XfDsbC was not detected during X. fastidiosa planktonic growth; however, after administering a sublethal copper shock, we observed an overexpression of XfDsbC that also occurred during planktonic growth. These results suggest that X. fastidiosa can use XfDsbC in vivo under oxidative stress conditions similar to those induced by copper. In addition, using dynamic light scattering and small-angle X-ray scattering, we observed that the oligomeric state of XfDsbC in vitro may be dependent on the redox environment. Under reducing conditions, XfDsbC is present as a dimer, whereas a putative tetrameric form was observed under nonreducing conditions. Taken together, our findings demonstrate the overexpression of XfDsbC during biofilm formation and provide the first structural model of a bacterial disulfide isomerase in solution. © 2012 The Authors Journal compilation © 2012 FEBS.

Phosphate Framework Electrode Materials for Sodium Ion Batteries.

Science.gov (United States)

Fang, Yongjin; Zhang, Jiexin; Xiao, Lifen; Ai, Xinping; Cao, Yuliang; Yang, Hanxi

2017-05-01

Sodium ion batteries (SIBs) have been considered as a promising alternative for the next generation of electric storage systems due to their similar electrochemistry to Li-ion batteries and the low cost of sodium resources. Exploring appropriate electrode materials with decent electrochemical performance is the key issue for development of sodium ion batteries. Due to the high structural stability, facile reaction mechanism and rich structural diversity, phosphate framework materials have attracted increasing attention as promising electrode materials for sodium ion batteries. Herein, we review the latest advances and progresses in the exploration of phosphate framework materials especially related to single-phosphates, pyrophosphates and mixed-phosphates. We provide the detailed and comprehensive understanding of structure-composition-performance relationship of materials and try to show the advantages and disadvantages of the materials for use in SIBs. In addition, some new perspectives about phosphate framework materials for SIBs are also discussed. Phosphate framework materials will be a competitive and attractive choice for use as electrodes in the next-generation of energy storage devices.

Photoelectron spectroscopy of phosphites and phosphates

Energy Technology Data Exchange (ETDEWEB)

Chattopadhyay, S.; Findley, G.L.; McGlynn, S.P.

1981-01-01

The ultraviolet photoelectron spectra (UPS) of trimethyl and triethyl phosphite, trimethyl and triethyl phosphate and four substituted phosphates are presented. Assignments are based on analogies to the UPS of phosphorus trichloride and phosphoryl trichloride and are substantiated by CNDO/2 computations. The mechanisms of P-O (axial) bond formation is discussed.

Phosphate uptake kinetics for four species of submerged freshwater macrophytes measured by a 33P phosphate radioisotope technique

DEFF Research Database (Denmark)

Christiansen, Nina Høj; Andersen, Frede Østergaard; Jensen, Henning S.

2016-01-01

Phosphate (Pi) uptake kinetics were determined in shoot and root tissues for four freshwater macrophyte species, Littorella uniflora, Potamogeton perfoliatus, Myriophyllum alterniflorum and Elodea canadensis, using a radioactive 33P phosphate technique. Collection of plant material in the oligotr...

The variable charge of andisols as affected by nanoparticles of rock phosphate and phosphate solubilizing bacteria

Science.gov (United States)

Arifin, M.; Nurlaeny, N.; Devnita, R.; Fitriatin, B. N.; Sandrawati, A.; Supriatna, Y.

2018-02-01

Andisols has a great potential as agriculture land, however, it has a high phosphorus retention, variable charge characteristics and high value of zero net charge or pH0. The research is aimed to study the effects of nanoparticles of rock phosphate (NPRP) and biofertilizer (phosphate solubilizing bacteria/PSB) on soil pH, pHo (zero point of charge, ZPC) and organic-C in one subgroup of Andisols, namely Acrudoxic Durudands, Ciater Region West Java. The research was conducted from October 2016 to February 2017 in Soil Physics Laboratory and Laboratory of Soil Chemistry and Fertility, Soil Science Department, Faculty of Agriculture, Universitas Padjadjaran. This experiment used a completely randomized factorial design, consisting of two factors and three replications. The first factor was nanoparticles of rock phosphate consist of 4 doses 0; 25; 50 and 75 g/1 kg soil and the second factor was biofertilizer dose consist of g/1 kg soil and without biofertilizer. Total treatment combinations were 8 with 3 replications, so there were 24 experimental plots. The results showed that in general NPRR and biofertilizer will decrease the value of soil pH throughout the incubation periods. There is an interaction between nanoparticles of rock phosphate and biofertilizer in decreasing pHo in the first month of incubation, but after 4-month incubation period, NPRP increased. Interaction between 75 g nanoparticles of rock phosphate with 1 g biofertilizer/1 kg soil in fourth months of incubation decreased soil organic-C to 3.35%.

Uranium and heavy metals in phosphate fertilizers

International Nuclear Information System (INIS)

Khater, A.E.M.

2008-01-01

Agricultural applications of chemical fertilizers are a worldwide practice. The specific activity of uranium-238 and heavy metals in phosphate fertilizers depends on the phosphate ore from which the fertilizer produced and on the chemical processing of the ore. Composite phosphate fertilizers samples where collected and the uranium-238 specific activity, in Bq/kg, and As, Cd, Cu, Pb, Se concentration, in ppm, were measured. The annual addition of these elements in soil due to fertilization were calculated and discussed. (author)(tk)

Uranium and heavy metals in phosphate fertilizers

International Nuclear Information System (INIS)

Khater, Ashraf E.M.; King Saud University, Riyadh

2008-01-01

Full text: Agricultural applications of chemical fertilizers are a worldwide practice. The specific activity of uranium-238 and heavy metals in phosphate fertilizers depends on the phosphate ore from which the fertilizer produced and on the chemical processing of the ore. Composite phosphate fertilizers samples were collected and the uranium-238 specific activity, in Bq/kg, and As, Cd, Cu, Pb, Se concentration were measured. The annual addition of these elements in soil due to soil fertilization were calculated and discussed. (author)

Mapping Soluble Guanylyl Cyclase and Protein Disulfide Isomerase Regions of Interaction.

Directory of Open Access Journals (Sweden)

Erin J Heckler

Full Text Available Soluble guanylyl cyclase (sGC is a heterodimeric nitric oxide (NO receptor that produces cyclic GMP. This signaling mechanism is a key component in the cardiovascular system. NO binds to heme in the β subunit and stimulates the catalytic conversion of GTP to cGMP several hundred fold. Several endogenous factors have been identified that modulate sGC function in vitro and in vivo. In previous work, we determined that protein disulfide isomerase (PDI interacts with sGC in a redox-dependent manner in vitro and that PDI inhibited NO-stimulated activity in cells. To our knowledge, this was the first report of a physical interaction between sGC and a thiol-redox protein. To characterize this interaction between sGC and PDI, we first identified peptide linkages between sGC and PDI, using a lysine cross-linking reagent and recently developed mass spectrometry analysis. Together with Flag-immunoprecipitation using sGC domain deletions, wild-type (WT and mutated PDI, regions of sGC involved in this interaction were identified. The observed data were further explored with computational modeling to gain insight into the interaction mechanism between sGC and oxidized PDI. Our results indicate that PDI interacts preferentially with the catalytic domain of sGC, thus providing a mechanism for PDI inhibition of sGC. A model in which PDI interacts with either the α or the β catalytic domain is proposed.

Creation of metal-independent hyperthermophilic L-arabinose isomerase by homologous recombination.

Science.gov (United States)

Hong, Young-Ho; Lee, Dong-Woo; Pyun, Yu-Ryang; Lee, Sung Haeng

2011-12-28

Hyperthermophilic L-arabinose isomerases (AIs) are useful in the commercial production of D-tagatose as a low-calorie bulk sweetener. Their catalysis and thermostability are highly dependent on metals, which is a major drawback in food applications. To study the role of metal ions in the thermostability and catalysis of hyperthermophilic AI, four enzyme chimeras were generated by PCR-based hybridization to replace the variable N- and C-terminal regions of hyperthermophilic Thermotoga maritima AI (TMAI) and thermophilic Geobacillus stearothermophilus AI (GSAI) with those of the homologous mesophilic Bacillus halodurans AI (BHAI). Unlike Mn(2+)-dependent TMAI, the GSAI- and TMAI-based hybrids with the 72 C-terminal residues of BHAI were not metal-dependent for catalytic activity. By contrast, the catalytic activities of the TMAI- and GSAI-based hybrids containing the N-terminus (residues 1-89) of BHAI were significantly enhanced by metals, but their thermostabilities were poor even in the presence of Mn(2+), indicating that the effects of metals on catalysis and thermostability involve different structural regions. Moreover, in contrast to the C-terminal truncate (Δ20 residues) of GSAI, the N-terminal truncate (Δ7 residues) exhibited no activity due to loss of its native structure. The data thus strongly suggest that the metal dependence of the catalysis and thermostability of hyperthermophilic AIs evolved separately to optimize their activity and thermostability at elevated temperatures. This may provide effective target regions for engineering, thereby meeting industrial demands for the production of d-tagatose.

Identification of triosephosphate isomerase as a novel allergen in Octopus fangsiao.

Science.gov (United States)

Yang, Yang; Chen, Zhong-Wei; Hurlburt, Barry K; Li, Gui-Ling; Zhang, Yong-Xia; Fei, Dan-Xia; Shen, Hai-Wang; Cao, Min-Jie; Liu, Guang-Ming

2017-05-01

Octopus is an important mollusk in human dietary for its nutritional value, however it also causes allergic reactions in humans. Major allergens from octopus have been identified, while the knowledge of novel allergens remains poor. In the present study, a novel allergen with molecular weight of 28kDa protein was purified from octopus (Octopus fangsiao) and identified as triosephosphate isomerase (TIM) by mass spectrometry. TIM aggregated beyond 45°C, and its IgE-binding activity was affected under extreme pH conditions due to the altered secondary structure. In simulated gastric fluid digestion, TIM can be degraded into small fragments, while retaining over 80% of the IgE-binding activity. The full-length cDNA of O. fangsiao TIM (1140bp) was cloned, which encodes 247 amino acid residues, and the entire recombinant TIM was successfully expressed in Escherichia coli BL21, which showed similar immunoreactivity to the native TIM. Different intensity of cross-reactivity among TIM from related species revealed the complexity of its epitopes. Eight linear epitopes of TIM were predicted following bioinformatic analysis. Furthermore, a conformational epitope (A 71 G 74 S 69 D 75 T 73 F 72 V 67 ) was confirmed by the phage display technology. The results revealed the physicochemical and immunological characteristics of TIM, which is significant in the development of hyposensitivity food and allergy diagnosis. Copyright © 2017 Elsevier Ltd. All rights reserved.

Availability of native and added phosphates for the soil

International Nuclear Information System (INIS)

Scivittaro, W.B.; Boaretto, A.E.; Muraoka, T.

1995-01-01

In superficial composite samples of two Red-Yellow Latosols with different physical and chemical properties, analyses were carried out on inorganic form of phosphorus as well as the availability of native and added phosphates. The method applied was soil phosphorus fractionation associated with isotopic dilution technique ( 32 P). The samples were taken from pots containing soils incubated for a month with fluid phosphatic fertilizers (phosphoric acid and 10-30-00 suspension) and solid phosphatic fertilizers (mono ammonium phosphate and triple superphosphate), at the rate of 210 mg P 2 O 5 /kg of soil. A control treatment was included. In both soils the availability of inorganic phosphorus fractions decreased at the following order: H 2 O-P > Al-P > Fe-P > CA-P > occluded-P. The water soluble and aluminium phosphates represented the main source of available P for the newly fertilizer, the iron phosphates were also an important source of available phosphorus. The soil phosphorus fixing capacity influenced the availability of native and added phosphates. (author). 17 refs, 3 tabs

Regularities in Low-Temperature Phosphatization of Silicates

Science.gov (United States)

Savenko, A. V.

2018-01-01

The regularities in low-temperature phosphatization of silicates are defined from long-term experiments on the interaction between different silicate minerals and phosphate-bearing solutions in a wide range of medium acidity. It is shown that the parameters of the reaction of phosphatization of hornblende, orthoclase, and labradorite have the same values as for clayey minerals (kaolinite and montmorillonite). This effect may appear, if phosphotization proceeds, not after silicate minerals with a different structure and composition, but after a secondary silicate phase formed upon interaction between silicates and water and stable in a certain pH range. Variation in the parameters of the reaction of phosphatization at pH ≈ 1.8 is due to the stability of the silicate phase different from that at higher pH values.

Alpha-tocopheryl phosphate: a novel, natural form of vitamin E.

Science.gov (United States)

Gianello, Robert; Libinaki, Roksan; Azzi, Angelo; Gavin, Paul D; Negis, Yesim; Zingg, Jean-Marc; Holt, Phillip; Keah, Hooi-Hong; Griffey, Annike; Smallridge, Andrew; West, Simon M; Ogru, Esra

2005-10-01

We have detected alpha-tocopheryl phosphate in biological tissues including liver and adipose tissue, as well as in a variety of foods, suggesting a ubiquitous presence in animal and plant tissue. Alpha-tocopheryl phosphate is a water-soluble molecule that is resistant to both acid and alkaline hydrolysis, making it undetectable using standard assays for vitamin E. A new method was therefore developed to allow the extraction of both alpha-tocopheryl phosphate and alpha-tocopherol from a single specimen. We used ESMS to detect endogenous alpha-tocopheryl phosphate in biological samples that also contained alpha-tocopherol. Due to the significance of these findings, further proof was required to unequivocally demonstrate the presence of endogenous alpha-tocopheryl phosphate in biological samples. Four independent methods of analysis were examined: HPLC, LCMS, LCMS/MS, and GCMS. Alpha-tocopherol phosphate was identified in all instances by comparison between standard alpha-tocopheryl phosphate and extracts of biological tissues. The results show that alpha-tocopheryl phosphate is a natural form of vitamin E. The discovery of endogenous alpha-tocopheryl phosphate has implications for the expanding knowledge of the roles of alpha-tocopherol in biological systems.

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)

Nano zinc phosphate coatings for enhanced corrosion resistance of mild steel

International Nuclear Information System (INIS)

Tamilselvi, M.; Kamaraj, P.; Arthanareeswari, M.; Devikala, S.

2015-01-01

Highlights: • Nano zinc phosphate coating on mild steel was developed. • Nano zinc phosphate coatings on mild steel showed enhanced corrosion resistance. • The nano ZnO increases the number of nucleating sites for phosphating. • Faster attainment of steady state during nano zinc phosphating. - Abstract: Nano crystalline zinc phosphate coatings were developed on mild steel surface using nano zinc oxide particles. The chemical composition and morphology of the coatings were analyzed by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). The particles size of the nano zinc phosphate coating developed was also characterized by TEM analysis. Potentiodynamic polarization and electrochemical impedance studies were carried out in 3.5% NaCl solution. Significant variations in the coating weight, morphology and corrosion resistance were observed as nano ZnO concentrations were varied from 0.25 to 2 g/L in the phosphating baths. The results showed that nano ZnO particles in the phosphating solution yielded phosphate coatings of higher coating weight, greater surface coverage and enhanced corrosion resistance than the normal zinc phosphate coatings (developed using normal ZnO particles in the phosphating baths). Better corrosion resistance was observed for coatings derived from phosphating bath containing 1.5 g/L nano ZnO. The activation effect brought about by the nano ZnO reduces the amount of accelerator (NaNO 2 ) required for phosphating

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.)

Magnesium-phosphate-glass cements with ceramic-type properties

Science.gov (United States)

Sugama, T.; Kukacka, L.E.

1982-09-23

Rapid setting magnesium phosphate (Mg glass) cementitious materials consisting of magnesium phosphate cement paste, polyborax and water-saturated aggregate, exhibits rapid setting and high early strength characteristics. The magnesium glass cement is prepared from a cation-leachable powder and a bivalent metallic ion-accepting liquid such as an aqueous solution of diammonium phosphate and ammonium polyphosphate. The cation-leachable powder includes a mixture of two different magnesium oxide powders processed and sized differently which when mixed with the bivalent metallic ion-accepting liquid provides the magnesium glass cement consisting primarily of magnesium ortho phosphate tetrahydrate, with magnesium hydroxide and magnesium ammonium phosphate hexahydrate also present. The polyborax serves as a set-retarder. The resulting magnesium mono- and polyphosphate cements are particularly suitable for use as a cementing matrix in rapid repair systems for deteriorated concrete structures as well as construction materials and surface coatings for fireproof structures.

Magnesium phosphate glass cements with ceramic-type properties

Science.gov (United States)

Sugama, Toshifumi; Kukacka, Lawrence E.

1984-03-13

Rapid setting magnesium phosphate (Mg glass) cementitious materials consisting of magnesium phosphate cement paste, polyborax and water-saturated aggregate exhibiting rapid setting and high early strength characteristics. The magnesium glass cement is prepared from a cation-leachable powder and a bivalent metallic ion-accepting liquid such as an aqueous solution of diammonium phosphate and ammonium polyphosphate. The cation-leachable powder includes a mixture of two different magnesium oxide powders processed and sized differently which when mixed with the bivalent metallic ion-accepting liquid provides the magnesium glass cement consisting primarily of magnesium ortho phosphate tetrahydrate, with magnesium hydroxide and magnesium ammonium phosphate hexahydrate also present. The polyborax serves as a set-retarder. The resulting magnesium mono- and polyphosphate cements are particularly suitable for use as a cementing matrix in rapid repair systems for deteriorated concrete structures as well as construction materials and surface coatings for fireproof structures.

A Phosphate Starvation-Inducible Ribonuclease of Bacillus licheniformis.

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Nguyen, Thanh Trung; Nguyen, Minh Hung; Nguyen, Huy Thuan; Nguyen, Hoang Anh; Le, Thi Hoi; Schweder, Thomas; Jürgen, Britta

2016-08-28

The BLi03719 protein of Bacillus licheniformis DSM13 belongs to the most abundant extracellular proteins under phosphate starvation conditions. In this study, the function of this phosphate starvation inducible protein was determined. An amino-acid sequence analysis of the BLi03719-encoding gene showed a high similarity with genes encoding the barnase of Bacillus amyloliquefaciens FZB42 and binase-like RNase of Bacillus pumilus SARF-032. The comparison of the control strain and a BLi03719-deficient strain revealed a strongly reduced extracellular ribonuclease activity of the mutant. Furthermore, this knockout mutant exhibited delayed growth with yeast RNA as an alternative phosphate and carbon source. These results suggest that BLi03719 is an extracellular ribonuclease expressed in B. licheniformis under phosphate starvation conditions. Finally, a BLi03719 mutant showed an advantageous effect on the overexpression of the heterologous amyE gene under phosphate-limited growth conditions.

Phosphate rock costs, prices and resources interaction.

Science.gov (United States)

Mew, M C

2016-01-15

This article gives the author's views and opinions as someone who has spent his working life analyzing the international phosphate sector as an independent consultant. His career spanned two price hike events in the mid-1970's and in 2008, both of which sparked considerable popular and academic interest concerning adequacy of phosphate rock resources, the impact of rising mining costs and the ability of mankind to feed future populations. An analysis of phosphate rock production costs derived from two major industry studies performed in 1983 and 2013 shows that in nominal terms, global average cash production costs increased by 27% to $38 per tonne fob mine in the 30 year period. In real terms, the global average cost of production has fallen. Despite the lack of upward pressure from increasing costs, phosphate rock market prices have shown two major spikes in the 30 years to 2013, with periods of less volatility in between. These price spike events can be seen to be related to the escalating investment cost required by new mine capacity, and as such can be expected to be repeated in future. As such, phosphate rock price volatility is likely to have more impact on food prices than rising phosphate rock production costs. However, as mining costs rise, recycling of P will also become increasingly driven by economics rather than legislation. Copyright © 2015 Elsevier B.V. All rights reserved.

Metal cation controls phosphate release in the myosin ATPase.

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Ge, Jinghua; Huang, Furong; Nesmelov, Yuri E

2017-11-01

Myosin is an enzyme that utilizes ATP to produce a conformational change generating a force. The kinetics of the myosin reverse recovery stroke depends on the metal cation complexed with ATP. The reverse recovery stroke is slow for MgATP and fast for MnATP. The metal ion coordinates the γ phosphate of ATP in the myosin active site. It is accepted that the reverse recovery stroke is correlated with the phosphate release; therefore, magnesium "holds" phosphate tighter than manganese. Magnesium and manganese are similar ions in terms of their chemical properties and the shell complexation; hence, we propose to use these ions to study the mechanism of the phosphate release. Analysis of octahedral complexes of magnesium and manganese show that the partial charge of magnesium is higher than that of manganese and the slightly larger size of manganese ion makes its ionic potential smaller. We hypothesize that electrostatics play a role in keeping and releasing the abstracted γ phosphate in the active site, and the stronger electric charge of magnesium ion holds γ phosphate tighter. We used stable myosin-nucleotide analog complex and Raman spectroscopy to examine the effect of the metal cation on the relative position of γ phosphate analog in the active site. We found that in the manganese complex, the γ phosphate analog is 0.01 nm further away from ADP than in the magnesium complex. We conclude that the ionic potential of the metal cation plays a role in the retention of the abstracted phosphate. © 2017 The Protein Society.

Engineering the l-Arabinose Isomerase from Enterococcus Faecium for d-Tagatose Synthesis

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Marylane de Sousa

2017-12-01

Full Text Available l-Arabinose isomerase (EC 5.3.1.4 (l-AI from Enterococcus faecium DBFIQ E36 was overproduced in Escherichia coli by designing a codon-optimized synthetic araA gene. Using this optimized gene, two N- and C-terminal His-tagged-l-AI proteins were produced. The cloning of the two chimeric genes into regulated expression vectors resulted in the production of high amounts of recombinant N-His-l-AI and C-His-l-AI in soluble and active forms. Both His-tagged enzymes were purified in a single step through metal-affinity chromatography and showed different kinetic and structural characteristics. Analytical ultracentrifugation revealed that C-His-l-AI was preferentially hexameric in solution, whereas N-His-l-AI was mainly monomeric. The specific activity of the N-His-l-AI at acidic pH was higher than that of C-His-l-AI and showed a maximum bioconversion yield of 26% at 50 °C for d-tagatose biosynthesis, with Km and Vmax parameters of 252 mM and 0.092 U mg−1, respectively. However, C-His-l-AI was more active and stable at alkaline pH than N-His-l-AI. N-His-l-AI follows a Michaelis-Menten kinetic, whereas C-His-l-AI fitted to a sigmoidal saturation curve.

Comparison between serum levels of carcinoembryonic antigen, sialic acid and phosphohexose isomerase in lung cancer

International Nuclear Information System (INIS)

Patel, P.S.; Raval, G.N.; Rawal, R.M.; Balar, D.B.; Patel, G.H.; Shah, P.M.; Patel, D.D.

1995-01-01

The identification and application of quantifiable tumor markers as adjuncts to clinical care is a story of both success and failure. The present study compared serum levels of carcinoembryogenic antigen (CEA) with total sialic acid/total protein (TSA/TP) ration and phosphohexose isomerase (PHI) in 192 untreated lung cancer patients as well as 80 age and sex matched controls (44 non-smokers). CEA values were significantly raised (p < 0.001) in smokers as compared to the non-smokers; whereas, TSA/TP and PHI values were comparable between the groups of the groups of the controls. All the bio-markers were significantly elevated (p < 0.00.1) in untreated lung cancer patients as compared to the controls. Receiver operating characteristic curve analysis revealed higher sensitivities of TSA/TP and PHI as compared to CEA at different specificity levels between 60% and 95%. Mean values of CEA, TSA/TP and PHI were higher in non-responders compared to the responders. The results indicate that TSA/TP and PHI are superior tumor markers than CEA for lung cancer patients. (author)

Cyanotoxins: a poison that frees phosphate.

Science.gov (United States)

Raven, John A

2010-10-12

Autotrophic organisms obtain phosphorus from the environment by secreting alkaline phosphatases that act on esters, resulting in inorganic phosphate that is then taken up. New work shows that the cyanobacterium Aphanizomenon ovalisporum obtains inorganic phosphate by secreting the cyanotoxin cylindrospermopsin, which induces alkaline phosphatase in other phytoplankton species. Copyright © 2010 Elsevier Ltd. All rights reserved.

Phosphate coating on stainless steel 304 sensitized

International Nuclear Information System (INIS)

Cruz V, J. P.; Vite T, J.; Castillo S, M.; Vite T, M.

2009-01-01

The stainless steel 304 can be sensitized when welding processes are applied, that causes the precipitation of chromium carbide in the grain limits, being promoted in this way the formation of galvanic cells and consequently the corrosion process. Using a phosphate coating is possible to retard the physiochemical damages that can to happen in the corrosion process. The stainless steel 304 substrate sensitized it is phosphate to base of Zn-Mn, in a immersion cell very hot. During the process was considered optimization values, for the characterization equipment of X-rays diffraction and scanning electron microscopy was used. The XRD technique confirmed the presence of the phases of manganese phosphate, zinc phosphate, as well as the phase of the stainless steel 304. When increasing the temperature from 60 to 90 C in the immersion process a homogeneous coating is obtained. (Author)

Corrosion inhibition by lithium zinc phosphate pigment

International Nuclear Information System (INIS)

Alibakhshi, E.; Ghasemi, E.; Mahdavian, M.

2013-01-01

Highlights: •Synthesis of lithium zinc phosphate (LZP) by chemical co-precipitation method. •Corrosion inhibition activity of pigments compare with zinc phosphate (ZP). •LZP showed superior corrosion inhibition effect in EIS measurements. •Evaluation of adhesion strength and dispersion stability. -- Abstract: Lithium zinc phosphate (LZP) has been synthesized through a co-precipitation process and characterized by XRD and IR spectroscopy. The inhibitive performances of this pigment for corrosion of mild steel have been discussed in comparison with the zinc phosphate (ZP) in the pigment extract solution by means of EIS and in the epoxy coating by means of salt spray. The EIS and salt spray results revealed the superior corrosion inhibitive effect of LZP compared to ZP. Moreover, adhesion strength and dispersion stability of the pigmented epoxy coating showed the advantage of LZP compared to ZP

Global radiological impact of the phosphate fertilizers

International Nuclear Information System (INIS)

Morales, Rudnei Karam; Alves, Rex Nazare

1996-01-01

About ninety percent of the products obtained in the phosphate industry are directly used in agriculture as fertilizers. The uranium, thorium and radium content in phosphate fertilizers pollute the soil, water and air, creating risks due to associated natural radiation. This work shows the concentration of radionuclides present in various products of the national and American phosphate fertilizers industry, and compared them with worldwide mean values. The radiological impact of the products on the environment is evaluated and suggestions are presented in order to minimize the risks due to radioactivity. (author)

Determination of radioactivity in Chinese phosphate rock and fertilizer

International Nuclear Information System (INIS)

Chen Jingjian; Zhu Yongyi; Yang Juncheng

1993-01-01

The presented paper reported the radioactivity of U-238, Ra-226, Th-232 and K-40 in Chinese phosphate rocks by gamma spectrographic analysis during 1985-1990. The results showed that the decay chain of U-238-Ra-226 was the main source of radionuclides in phosphate rocks. The radionuclides in phosphate fertilizer differed from the forms of phosphate fertilizer. U-238 was the most important radionuclide in phosphoric compound fertilizer. The transfer rate of radionuclides was also estimated. (2 figs., 1 tab.)

Engineering Potato Starch with a Higher Phosphate Content.

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Xuan Xu

Full Text Available Phosphate esters are responsible for valuable and unique functionalities of starch for industrial applications. Also in the cell phosphate esters play a role in starch metabolism, which so far has not been well characterized in storage starch. Laforin, a human enzyme composed of a carbohydrate-binding module and a dual-specificity phosphatase domain, is involved in the dephosphorylation of glycogen. To modify phosphate content and better understand starch (dephosphorylation in storage starch, laforin was engineered and introduced into potato (cultivar Kardal. Interestingly, expression of an (engineered laforin in potato resulted in significantly higher phosphate content of starch, and this result was confirmed in amylose-free potato genetic background (amf. Modified starches exhibited altered granule morphology and size compared to the control. About 20-30% of the transgenic lines of each series showed red-staining granules upon incubation with iodine, and contained higher phosphate content than the blue-stained starch granules. Moreover, low amylose content and altered gelatinization properties were observed in these red-stained starches. Principle component and correlation analysis disclosed a complex correlation between starch composition and starch physico-chemical properties. Ultimately, the expression level of endogenous genes involved in starch metabolism was analysed, revealing a compensatory response to the decrease of phosphate content in potato starch. This study provides a new perspective for engineering starch phosphate content in planta by making use of the compensatory mechanism in the plant itself.

Phosphate and Cardiovascular Disease beyond Chronic Kidney Disease and Vascular Calcification

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Sinee Disthabanchong

2018-01-01

Full Text Available Phosphate is essential for life but its accumulation can be detrimental. In end-stage renal disease, widespread vascular calcification occurs as a result of chronic phosphate load. The accumulation of phosphate is likely to occur long before the rise in serum phosphate above the normal range since several observational studies in both general population and early-stage CKD patients have identified the relationship between high-normal serum phosphate and adverse cardiovascular outcomes. Consumption of food high in phosphate increases both fasting and postprandial serum phosphate and habitual intake of high phosphate diet is associated with aging, cardiac hypertrophy, endothelial dysfunction, and subclinical atherosclerosis. The decline in renal function and dietary phosphate load can increase circulating fibroblast growth factor-23 (FGF-23 which may have a direct impact on cardiomyocytes. Increased FGF-23 levels in both CKD and general populations are associated with left ventricular hypertrophy, congestive heart failure, atrial fibrillation, and mortality. Increased extracellular phosphate directly affects endothelial cells causing cell apoptosis and vascular smooth muscle cells (VSMCs causing transformation to osteogenic phenotype. Excess of calcium and phosphate in the circulation can promote the formation of protein-mineral complex called calciprotein particles (CPPs. In CKD, these CPPs contain less calcification inhibitors, induce inflammation, and promote VSMC calcification.

An efficient method for qualitative screening of phosphate-solubilizing bacteria.

Science.gov (United States)

Mehta, S; Nautiyal, C S

2001-07-01

An efficient protocol was developed for qualitative screening of phosphate-solubilizing bacteria, based upon visual observation. Our results indicate that, by using our formulation containing bromophenol blue, it is possible to quickly screen on a qualitative basis the phosphate-solubilizing bacteria. Qualitative analysis of the phosphate solubilized by various groups correlated well with grouping based upon quantitative analysis of bacteria isolated from soil, effect of carbon, nitrogen, salts, and phosphate solubilization-defective transposon mutants. However, unlike quantitative analysis methods that involve time-consuming biochemical procedures, the time for screening phosphate-solubilizing bacteria is significantly reduced by using our simple protocol. Therefore, it is envisaged that usage of this formulation based upon qualitative analysis will be salutary for the quick screening of phosphate-solubilizing bacteria. Our results indicate that the formulation can also be used as a quality control test for expeditiously screening the commercial bioinoculant preparations, based on phosphate solubilizers.

Progranulin, a glycoprotein deficient in frontotemporal dementia, is a novel substrate of several protein disulfide isomerase family proteins.

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Sandra Almeida

Full Text Available The reduced production or activity of the cysteine-rich glycoprotein progranulin is responsible for about 20% of cases of familial frontotemporal dementia. However, little is known about the molecular mechanisms that govern the level and secretion of progranulin. Here we show that progranulin is expressed in mouse cortical neurons and more prominently in mouse microglia in culture and is abundant in the endoplasmic reticulum (ER and Golgi. Using chemical crosslinking, immunoprecipitation, and mass spectrometry, we found that progranulin is bound to a network of ER Ca(2+-binding chaperones including BiP, calreticulin, GRP94, and four members of the protein disulfide isomerase (PDI family. Loss of ERp57 inhibits progranulin secretion. Thus, progranulin is a novel substrate of several PDI family proteins and modulation of the ER chaperone network may be a therapeutic target for controlling progranulin secretion.

Influence of protonation or alkylation of the phosphate group on the e. s. r. spectra and on the rate of phosphate elimination from 2-methoxyethyl phosphate 2-yl radicals. [. gamma. rays

Energy Technology Data Exchange (ETDEWEB)

Behrens, G; Koltzenburg, G; Ritter, A; Schulte-Frohlinde, D [Max-Planck-Institut fuer Kohlenforschung, Muelheim an der Ruhr (Germany, F.R.). Inst. fuer Strahlenchemie

1978-02-01

The e.s.r. spectra of l-yl, 2-yl and 3'-yl methoxethyl phosphate radicals derived from CH/sub 3/OCH/sub 2/CH/sub 2/-OPO/sub 3/H/sub 2/ by hydrogen abstraction have been measured in aqueous solutions and the hyperfine constants determined. The coupling constants vary strongly with protonation or alkylation of the phosphate group. The 2-yl radicals eliminate phosphate. The rate-constants for the elimination (ksub(e)) have been estimated by e.s.r. measurements and by product studies as a function of pH using /sup 60/Co ..gamma..-radiolysis. The ksub(e) values vary from approximately 0.3 s/sup -1/ for the CH/sub 3/OCHCH/sub 2/OPO/sub 3//sup - -/ radical and approximately 10/sup 3/s/sup -1/ for CH/sub 3/OCHCH/sub 2/OPO/sub 3/H/sup -/, to approximately 3 x 10/sup 6/s/sup -1/ for CH/sub 3/OCHCH/sub 2/OPO/sub 3/H/sub 2/. Alkylation of the phosphate group increased the elimination rate-constant to a similar extent as protonation. The results support a recent mechanism which described the OH-radical-induced single-strand breaks of DNA in aqueous solution starting from the C-4' radical of the sugar moiety. It is further concluded the C-4' radical of DNA eliminates the 3'-phosphate group faster than the 5'-phosphate group.

Final Report - Assessment of Potential Phosphate Ion-Cementitious Materials Interactions

International Nuclear Information System (INIS)

Naus, Dan J.; Mattus, Catherine H.; Dole, Leslie Robert

2007-01-01

The objectives of this limited study were to: (1) review the potential for degradation of cementitious materials due to exposure to high concentrations of phosphate ions; (2) provide an improved understanding of any significant factors that may lead to a requirement to establish exposure limits for concrete structures exposed to soils or ground waters containing high levels of phosphate ions; (3) recommend, as appropriate, whether a limitation on phosphate ion concentration in soils or ground water is required to avoid degradation of concrete structures; and (4) provide a 'primer' on factors that can affect the durability of concrete materials and structures in nuclear power plants. An assessment of the potential effects of phosphate ions on cementitious materials was made through a review of the literature, contacts with concrete research personnel, and conduct of a 'bench-scale' laboratory investigation. Results of these activities indicate that: no harmful interactions occur between phosphates and cementitious materials unless phosphates are present in the form of phosphoric acid; phosphates have been incorporated into concrete as set retarders, and phosphate cements have been used for infrastructure repair; no standards or guidelines exist pertaining to applications of reinforced concrete structures in high-phosphate environments; interactions of phosphate ions and cementitious materials has not been a concern of the research community; and laboratory results indicate similar performance of specimens cured in phosphate solutions and those cured in a calcium hydroxide solution after exposure periods of up to eighteen months. Relative to the 'primer,' a separate NUREG report has been prepared that provides a review of pertinent factors that can affect the durability of nuclear power plant reinforced concrete structures

Final Report - Assessment of Potential Phosphate Ion-Cementitious Materials Interactions

Energy Technology Data Exchange (ETDEWEB)

Naus, Dan J [ORNL; Mattus, Catherine H [ORNL; Dole, Leslie Robert [ORNL

2007-06-01

The objectives of this limited study were to: (1) review the potential for degradation of cementitious materials due to exposure to high concentrations of phosphate ions; (2) provide an improved understanding of any significant factors that may lead to a requirement to establish exposure limits for concrete structures exposed to soils or ground waters containing high levels of phosphate ions; (3) recommend, as appropriate, whether a limitation on phosphate ion concentration in soils or ground water is required to avoid degradation of concrete structures; and (4) provide a "primer" on factors that can affect the durability of concrete materials and structures in nuclear power plants. An assessment of the potential effects of phosphate ions on cementitious materials was made through a review of the literature, contacts with concrete research personnel, and conduct of a "bench-scale" laboratory investigation. Results of these activities indicate that: no harmful interactions occur between phosphates and cementitious materials unless phosphates are present in the form of phosphoric acid; phosphates have been incorporated into concrete as set retarders, and phosphate cements have been used for infrastructure repair; no standards or guidelines exist pertaining to applications of reinforced concrete structures in high-phosphate environments; interactions of phosphate ions and cementitious materials has not been a concern of the research community; and laboratory results indicate similar performance of specimens cured in phosphate solutions and those cured in a calcium hydroxide solution after exposure periods of up to eighteen months. Relative to the "primer," a separate NUREG report has been prepared that provides a review of pertinent factors that can affect the durability of nuclear power plant reinforced concrete structures.

Serum phosphate and cognitive function in older men.

Science.gov (United States)

Slinin, Yelena; Vo, Tien; Taylor, Brent C; Murray, Anne M; Schousboe, John; Langsetmo, Lisa; Ensrud, Kristine

2018-01-01

Determine whether serum phosphate is associated with concurrent cognitive impairment and subsequent cognitive decline in older men independent of demographic covariates and atherosclerotic risk factors. In a prospective study of 5529 men enrolled in the Osteoporotic Fractures in Men study, we measured baseline serum phosphate, baseline cognitive function, and change in cognitive function between baseline and follow-up exams an average of 4.6 years later using the Modified Mini-Mental State (3MS) Examination and Trails B. There was no association between serum phosphate and odds of cognitive impairment as assessed by baseline 3MS score or risk of cognitive decline as assessed by longitudinal change in 3MS score. Higher baseline serum phosphate was associated with higher odds of poor executive function as assessed by Trails B with fully adjusted odds ratios 1.12 (95% confidence interval: 0.83-1.52), 1.31 (0.97-1.77), and 1.45 (1.08-1.94) for men in the second, third, and fourth versus the bottom quartile (referent group) of serum phosphate (p-trend 0.007). However, higher phosphate level was not associated with risk of decline in executive function as assessed by longitudinal change in Trails B score with fully adjusted odds ratios 0.94 (95% confidence interval 0.69-1.28), 0.96 (0.70-1.32), and 1.21 (0.89-1.66) for men in the second, third, and fourth versus the bottom quartile (referent group) of serum phosphate (p-trend 0.22). Higher serum phosphate in older men was associated with a higher likelihood of poor executive function, but not with impaired global cognitive function or decline in executive or global cognition. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

EFFECT OF SODIUM PHOSPHATES ON SELECTED FOOD GRADE BACTERIA

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Stanislav Kráčmar

2011-04-01

Full Text Available The aim of this study was to examine the inhibitory effect in vitro of selected sodium phosphates (under the corporate names Hexa 68, Hexa 70, Trikrystal, FST, Pyro 52, KPS, Didi on selected gram-positive and gram-negative bacteria. Seven different concentrations of each phosphate were used. Sensitivity of the bacterial strains to phosphates was observed in broth supplemented with salts. In vitro was showed a negative effect of various phosphates on growth of selected gram-positive bacteria. Orthophosphates and diphosphates (pyrophosphates did not have significant inhibitory effect on tested bacteria at neutral pH. With the exception of phosphate Trikrystal has not been found in vitro significant inhibitory effects on gram-negative bacteria.doi:10.5219/141

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.

Thermo-tolerant phosphate-solubilizing microbes for multi-functional biofertilizer preparation.

Science.gov (United States)

Chang, Cheng-Hsiung; Yang, Shang-Shyng

2009-02-01

In order to prepare the multi-functional biofertilizer, thermo-tolerant phosphate-solubilizing microbes including bacteria, actinomycetes, and fungi were isolated from different compost plants and biofertilizers. Except Streptomycesthermophilus J57 which lacked pectinase, all isolates possessed amylase, CMCase, chitinase, pectinase, protease, lipase, and nitrogenase activities. All isolates could solubilize calcium phosphate and Israel rock phosphate; various isolates could solubilize aluminum phosphate, iron phosphate, and hydroxyapatite. During composting, biofertilizers inoculated with the tested microbes had a significantly higher temperature, ash content, pH, total nitrogen, soluble phosphorus content, and germination rate than non-inoculated biofertilizer; total organic carbon and carbon-to-nitrogen ratio showed the opposite pattern. Adding these microbes can shorten the period of maturity, improve the quality, increase the soluble phosphorus content, and enhance the populations of phosphate-solubilizing and proteolytic microbes in biofertilizers. Therefore, inoculating thermo-tolerant phosphate-solubilizing microbes into agricultural and animal wastes represents a practical strategy for preparing multi-functional biofertilizer.

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

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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

Preparation and Characterization of Porous Calcium Phosphate Bioceramics

Institute of Scientific and Technical Information of China (English)

Honglian Dai; Xinyu Wang; Yinchao Han; Xin Jiang; Shipu Li

2011-01-01

β-tricalcium phosphate (β-TCP) powder and Na2O-CaO-MgO-P2O5 glass binder were synthesized and mixed, and then the biodegradable porous calcium phosphate ceramics were successfully prepared by foaming and sintering at 850℃. The as-prepared ceramics possess a high porosity with partial three-dimension interconnected macro- and micro-pores. As in vitro experiment testified, the calcium phosphate ceramics (CPCs) has good degradability.

Titrimetric determination of uranium in tributyl phosphate

International Nuclear Information System (INIS)

Sobkowska, A.

1978-01-01

The titrimetric method involving the reduction of U(VI) to uranium(IV) by iron(II) in phosphoric acid, selective oxidation of the excess of iron(II) and potentiometric titration with dichromate was directly used for the determination of uranium in tributyl phosphate mixtures. The procedure was applied to solutions containing more than 2 mg of uranium in the sample but the highest precision and accuracy were obtained in the range from 20 to 200 mg of uranium. Dibutyl phosphate and monobutyl phosphate as well as the other radiolysis products of TBP had no influence on the results of determinations. (author)

Fibroblast Growth Factor 23 (FGF23 and Disorders of Phosphate Metabolism

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Tasuku Saito

2009-01-01

Full Text Available Derangements in serum phosphate level result in rickets/osteomalacia or ectopic calcification indicating that healthy people without these abnormalities maintain serum phosphate within certain ranges. These results indicate that there must be a regulatory mechanism of serum phosphate level. Fibroblast growth factor 23 (FGF23 was identified as the last member of FGF family. FGF23 is produced by bone and reduces serum phosphate level by suppressing phosphate reabsorption in proximal tubules and intestinal phosphate absorption through lowering 1,25-dihydroxyvitamin D level. It has been shown that excess and deficient actions of FGF23 result in hypophosphatemic rickets/osteomalacia and hyperphosphatemic tumoral calcinosis, respectively. These results indicate that FGF23 works as a hormone, and several disorders of phosphate metabolism can be viewed as endocrine diseases. It may become possible to treat patients with abnormal phosphate metabolism by pharmacologically modifying the activity of FGF23.

Phosphate limitation induces sporulation in the chytridiomycete Blastocladiella emersonii.

Science.gov (United States)

Bongiorno, Vagner Alexandre; Ferreira da Cruz, Angela; Nunis da Silva, Antonio; Corrêa, Luiz Carlos

2012-09-01

The cell cycle is controlled by numerous mechanisms that ensure correct cell division. If growth is not possible, cells may eventually promote autophagy, differentiation, or apoptosis. Microorganisms interrupt their growth and differentiate under general nutrient limitation. We analyzed the effects of phosphate limitation on growth and sporulation in the chytridiomycete Blastocladiella emersonii using kinetic data, phase-contrast, and laser confocal microscopy. Under phosphate limitation, zoospores germinated and subsequently formed 2-4 spores, regardless of the nutritional content of the medium. The removal of phosphate at any time during growth induced sporulation of vegetative cells. If phosphate was later added to the same cultures, growth was restored if the cells were not yet committed to sporulation. The cycles of addition and withdrawal of phosphate from growth medium resulted in cycles of germination-growth, germination-sporulation, or germination-growth-sporulation. These results show that phosphate limitation is sufficient to interrupt cell growth and to induce complete sporulation in B. emersonii. We concluded that the determination of growth or sporulation in this microorganism is linked to phosphate availability when other nutrients are not limiting. This result provides a new tool for the dissection of nutrient-energy and signal pathways in cell growth and differentiation.

A study of the inhibiton of copper corrosion by triethyl phosphate and triphenyl phosphate self-assembled monolayers

Directory of Open Access Journals (Sweden)

HOUYI MA

2006-02-01

Full Text Available Two kinds of phosphates, triethyl phosphate (TEP and triphenyl phosphate (TPP, were used to form self-assembled monolayers for the inhibition of the corrosion of copper in 0.2 mol dm–3 NaCl solution. Electrochemical impedance spectroscopy (EIS was applied to investigate the inhibition effects. The results showed that their inhibition ability first increased with increasing immersion time in ethanolic solutions of the corresponding compounds. However, when the immersion time was increased over some critical point, the inhibition effect decreased. For the same immersion time, the inhibition effect of the TPP monolayer was more pronounced than that of the TEP monolayer. Thus, ab initio calculations were used to interpret the relationship between the inhibition effects and the structures of the compounds.

Lanthanum-modified bentonite: potential for efficient removal of phosphates from fishpond effluents.

Science.gov (United States)

Kurzbaum, Eyal; Raizner, Yasmin; Cohen, Oded; Rubinstein, Guy; Bar Shalom, Oded

2017-06-01

Adsorption has been suggested as an effective method for removing phosphates from agricultural wastewater effluents that contain relatively high phosphate concentrations. The present study focused on the use of a bentonite-lanthanum clay (Phoslock ® ) for reducing the dissolved phosphate concentration in fishpond effluents. Batch experiments with synthetic phosphate-spiked solutions and with fishpond effluents were performed in order to determine adsorption equilibrium isotherms and kinetics as well as to determine the efficiency of Phoslock ® in removing phosphate from these solutions. In the synthetic phosphate-spiked solution, the mean maximum phosphate adsorption capacity was 92 mg Phoslock ® /mg phosphate removal. A ratio of 50, 100, and 200 mg Phoslock ® /mg phosphate removal was found for complete phosphate removal from the fishpond effluents, where higher doses of Phoslock ® led to a faster removal rate (94% removal within the first 150 min). These results show that bentonite-lanthanum clay can be employed for designing a treatment process for efficient phosphate removal from fishpond effluents.

Prevention of radioactive contamination in the manufacture of phosphate fertilizers

International Nuclear Information System (INIS)

Romero G, E.T.

1995-01-01

In this work was studied the separation of uranium from the phosphate rock to decrease the level of radioactivity in the phosphate fertilizers, this prevents the redistribution of uranium in the environment. The uranium leaching conditions from phosphate rock were estimated using alkaline solutions. The changes in the natural phosphate rock after leaching were studied. The amenability to separate the uranium from phosphate rock with ammonium carbonate / bicarbonate solution was determined. The uranium extraction was approximately 40%. The leaching conditions showed high selectivity for uranium without changes in the ore structure. The bulk ore was not dissolved. (Author)

Phosphate removal from digested sludge supernatant using modified fly ash.

Science.gov (United States)

Xu, Ke; Deng, Tong; Liu, Juntan; Peng, Weigong

2012-05-01

The removal of phosphate in digested sludge supernatant by modified coal fly ash was investigated in this study. Modification of the fly ash by the addition of sulfuric acid could significantly enhance its immobilization ability. The experimental results also showed that adsorption of phosphate by the modified fly ash was rapid with the removal percentage of phosphate reaching an equilibrium of 98.62% in less than 5 minutes. The optimum pH for phosphate removal was 9 and the removal percentage increased with increasing adsorbent dosage. The effect of temperature on phosphate removal efficiency was not significant from 20 to 40 degrees C. X-ray diffraction and scanning electron microscope analyses showed that phosphate formed an amorphous precipitate with water-soluble calcium, aluminum, and iron ions in the modified fly ash.

A study of phosphate absorption by magnesium iron hydroxycarbonate.

Science.gov (United States)

Du, Yi; Rees, Nicholas; O'Hare, Dermot

2009-10-21

A study of the mechanism of phosphate adsorption by magnesium iron hydroxycarbonate, [Mg(2.25)Fe(0.75)(OH)(6)](CO(3))(0.37).0.65H(2)O over a range of pH has been carried out. The efficiency of the phosphate removal from aqueous solution has been investigated between pH 3-9 and the resulting solid phases have been studied by elemental analysis, XRD, FT-IR, Raman, HRTEM, EDX and solid-state MAS (31)P NMR. The analytical and spectroscopic data suggest that phosphate removal from solution occurs not by anion intercalation of the relevant phosphorous oxyanion (H(2)PO(4)(-) or HPO(4)(2-)) into the LDH but by the precipitation of either an insoluble iron hydrogen phosphate hydrate and/or a magnesium phosphate hydrate.

Evaluation methods used for phosphate-solubilizing bacteria ...

African Journals Online (AJOL)

This work aimed to evaluate the different selection methods and select inorganic phosphorus-solubilizing bacteria as potential plant-growth promoters. Bacterial isolates obtained from sugarcane roots and soil were tested using solid growth media containing bicalcium phosphate and Irecê Apatite ground rock phosphate as ...

Effect of Casein Phosphopeptide-Amorphous Calcium Phosphate and Three Calcium Phosphate on Enamel Microhardness.

Science.gov (United States)

Haghgou, En Hr; Haghgoo, Roza; Roholahi, Mohamad R; Ghorbani, Zahra

2017-07-01

This study aims to investigate the effect of casein phos-phopeptide-amorphous calcium phosphate and three calcium phosphate (CPP-ACP and TCP) on increasing the microhardness of human enamel after induction of erosion. A total of 26 healthy human-impacted third molar teeth were chosen, and their hardness measured using a microhardness testing machine. The samples were immersed in Coca Cola (pH = 4.7) for 8 minutes. Then, micro-hardness was measured again, and these samples were randomly divided into four groups (two control groups and two experimental groups). (1) Negative control group: Artificial saliva was used for 10 minutes, (2) positive control group: Fluoride gel was used for 10 minutes, (3) β-TCP group: TCP was used for 10 minutes, (4) CCP-ACP group: CCP-ACP was used for 10 minutes. The final microhardness of those samples was measured, and the changes in microhardness of teeth within group and between groups were analyzed using the paired and analysis of variance tests respectively. Results were considered statistically significant at a level of p < 0.05. No significant difference was observed in microhard-ness between CPP-ACP group and TCP group (p = 0.368) during the time microhardness significantly dropped after soaking in soda. Casein phosphopeptide-amorphous calcium phosphate and TCP increased the microhardness of teeth. The increase in hardness in the TCP group was higher than in the CPP-ACP group, but this difference was not significant (p = 0.36). Casein phosphopeptide-amorphous calcium phosphate and TCP can affect the remineralization of erosive lesions.

Preparation and Characterization of Apatitic Biphasic Calcium Phosphate

International Nuclear Information System (INIS)

Thin Thin Nwe; Kyaw Naing; Khin Mar Tun; Nyunt Wynn

2005-09-01

The apatitic biphasic calcium phosphate (ABcp) consisting of hydroxyapatite (HA) and -tricalcium phosphate ( -Tcp) has been prepared by precipitation technique using slaked lime and orthophosphoric acid. The X-ray diffraction analysis of the product I (hydroxyapatite) revealed that ABcp was partially crystalline state. However, on heating at 800 C for 8 hrs, XRD pattern indicated a perfectly crystalline form of ABcp. This observation was supported by FT-IR measurement. The change in morphology regarding in the functional nature was infered by the shift in the FT-IR frequency. The optimization of the apatitic biphasic calcium phosphate was done by the variation of disodium hydrogen phosphate concentration, setting time, hardening time as well as compressive strength. The perpared cement may be used as an artificial substitution bone

Characterization of cement calcium phosphate for use dental

International Nuclear Information System (INIS)

Barros, C.M.B.; Oliveira, S.V.; Silva, M.C.; Marques, J.B.; Fook, M.V.L.

2011-01-01

Calcium phosphates are interesting biological and medical attention due to its occurrence in different animal species and humans. Ceramics based on calcium phosphate in the form of implants or porous particulate materials, have proven to be suitable replacements for bone tissue when they are only subjected to small mechanical stresses. Was obtained research laboratory DEMA/UFCG a calcium phosphate phase. The goal is to characterize the material by X-ray diffraction (XRD) in order to analyze what the phases and infrared spectroscopy (FTIR) to identify the absorption bands of the bonding characteristic. Was identified by XRD phase present in the sample is hydroxyapatite Ca/P 1.67. In infrared spectroscopy has absorption bands characteristic of the phosphate group at 1032 cm1 region. (author)

Metal Phosphates as Intermediate Temperature Proton Conducting Electrolytes

DEFF Research Database (Denmark)

Huang, Yunjie; Li, Q.F.; Pan, Chao

2012-01-01

A series of metal phosphates were synthesized and screened as potential proton conductor electrolytes for fuel cells and electrolysers operational at intermediate temperatures. Among the selected, niobium and bismuth phosphates exhibited a proton conductivity of 10-2 and 10-7 S cm-1, respectively......, under the anhydrous atmosphere at 250 °C, showing close correlation with the presence of hydroxyl groups in the phosphate phases. At the water partial pressure of above 0.6 atm, both phosphates possessed a proton conductivity to a level of above 3 x 10-2 S cm-1. Reasonable stability of the proton...... conductivity was observed under either a constant low water partial pressure or under a humidity cycling test within a period of more than 80 hours....

Immobilization of fission products in phosphate ceramic waste forms

Energy Technology Data Exchange (ETDEWEB)

Singh, D.; Wagh, A. [Argonne National Lab., IL (United States)

1997-10-01

Chemically bonded phosphate ceramics (CBPCs) have several advantages that make them ideal candidates for containing radioactive and hazardous wastes. In general, phosphates have high solid-solution capacities for incorporating radionuclides, as evidenced by several phosphates (e.g., monazites and apatites) that are natural analogs of radioactive and rare-earth elements. The phosphates have high radiation stability, are refractory, and will not degrade in the presence of internal heating by fission products. Dense and hard CBPCs can be fabricated inexpensively and at low temperature by acid-base reactions between an inorganic oxide/hydroxide powder and either phosphoric acid or an acid-phosphate solution. The resulting phosphates are extremely insoluble in aqueous media and have excellent long-term durability. CBPCs offer the dual stabilization mechanisms of chemical fixation and physical encapsulation, resulting in superior waste forms. The goal of this task is develop and demonstrate the feasibility of CBPCs for S/S of wastes containing fission products. The focus of this work is to develop a low-temperature CBPC immobilization system for eluted {sup 99}Tc wastes from sorption processes.

A novel biphasic calcium phosphate derived from fish otoliths

Science.gov (United States)

Montañez-Supelano, N. D.; Sandoval-Amador, A.; Estupiñan-Durán, H. A.; Y Peña-Ballesteros, D.

2017-12-01

Calcium phosphates are bioceramics that have been widely used as bone substitutes because they encourage the formation of bone on their surface and can improve the healing of the bone. Hydroxyapatite HA (calcium/phosphorus ratio of 1.67) and tricalcium phosphate TCP (calcium/phosphorus ratio of 1.50) are the most common calcium phosphates. Natural materials have begun to be tested to make HA or TCP such as shells of cardiidae (family of mollusks) and eggshells. The calcium phosphate obtained has a high ability to precipitate apatite. In this work, the mixed phase ceramic of beta-Tri-calcium phosphate / hydroxyapatite (β-TCP/HA) was synthesized by aqueous precipitation from fish otoliths, which are monomineralic species composed of aragonite. Otoliths of the specie Plagioscion squamosissimus, commonly called the river croaker, were used. Techniques such as DRX, Raman spectroscopy and SEM-EDS were used to characterize the raw material and the obtained material. X-ray diffraction analysis revealed the presence of two crystalline phases of calcium phosphates with 86.2% crystallinity. SEM micrographs showed agglomeration of particles with porous structure and submicron particle sizes.

Metal complex derivatives of hydrogen uranyl phosphate

International Nuclear Information System (INIS)

Grohol, D.; Blinn, E.L.

1994-01-01

Derivatives of hydrogen uranyl phosphate were prepared by incorporating transition metal complexes into the uranyl phosphate matrix. The transition metal complexes employed include bis(ethylenediamine)copper(II), bis(1,3-propanediamine)copper(II) chloride, (triethylenetetramine)copper(II), (1,4,8,11-tetraazacyclotetradecane)copper(II), (1,4,8,12-tetraazacyclopentadecane)copper(II), (1,4,8,11-tetraazacyclotetradecane)nickel(II) chloride, (triethylenetetramine)nickel(II) and others. The chemical analyses of these derivatives indicated that the incorporation of the transition metal complexes into the uranyl phosphate matrix via ion exchange was not stoichiometric. The extent of ion exchange is dependent on the size and structure of the transition metal complex. All complexes were characterized by X-ray powder diffractometry, electronic and infrared spectra, thermal analyses and chemical analysis. An attempt was made to correlate the degree of quenching of the luminescence of the uranyl ion to the spacing between the uranyl phosphate layers in the derivatives

From energy-rich phosphate compounds to warfare agents: A review on the chemistry of organic phosphate compounds

Directory of Open Access Journals (Sweden)

Luciano Albino Giusti

2008-12-01

Full Text Available The chemistry of the phosphorus-oxygen bond is widely used in biological systems in many processes, such as energy transduction and the storage, transmission and expression of genetic information, which are essential to living beings in relation to a wide variety of functions. Compounds containing this bond have been designed for many purposes, ranging from agricultural defense systems, in order to increase food production, to nerve agents, for complaining use in warfare. In this review, features related to the chemistry of organic phosphate compounds are discussed, with particular emphasis on the role of phosphate compounds in biochemical events and in nerve agents. To this aim, the energy-rich phosphate compounds are focused, particularly the mode of their use as energy currency in cells. Historical and recent studies carried out by research groups have tried to elucidate the mechanism of action of enzymes responsible for energy transduction through the use of biochemical studies, enzyme models, and artificial enzymes. Finally, recent studies on the detoxification of nerve agents based on phosphorous esters are presented, and on the utilization of chromogenic and fluorogenic chemosensors for the detection of these phosphate species.

TUCS/phosphate mineralization of actinides

Energy Technology Data Exchange (ETDEWEB)

Nash, K.L. [Argonne National Lab., IL (United States)

1997-10-01

This program has as its objective the development of a new technology that combines cation exchange and mineralization to reduce the concentration of heavy metals (in particular actinides) in groundwaters. The treatment regimen must be compatible with the groundwater and soil, potentially using groundwater/soil components to aid in the immobilization process. The delivery system (probably a water-soluble chelating agent) should first concentrate the radionuclides then release the precipitating anion, which forms thermodynamically stable mineral phases, either with the target metal ions alone or in combination with matrix cations. This approach should generate thermodynamically stable mineral phases resistant to weathering. The chelating agent should decompose spontaneously with time, release the mineralizing agent, and leave a residue that does not interfere with mineral formation. For the actinides, the ideal compound probably will release phosphate, as actinide phosphate mineral phases are among the least soluble species for these metals. The most promising means of delivering the precipitant would be to use a water-soluble, hydrolytically unstable complexant that functions in the initial stages as a cation exchanger to concentrate the metal ions. As it decomposes, the chelating agent releases phosphate to foster formation of crystalline mineral phases. Because it involves only the application of inexpensive reagents, the method of phosphate mineralization promises to be an economical alternative for in situ immobilization of radionuclides (actinides in particular). The method relies on the inherent (thermodynamic) stability of actinide mineral phases.

Cloning and expression of pineapple sucrose- phosphate synthase ...

African Journals Online (AJOL)

hope&shola

2010-12-06

Dec 6, 2010 ... phosphate; EDTA, ethylene diamine tetraacetic acid; Ivr, invertase; SS .... phenolics, tannins and artifacts due to differences of tissue composition ..... Banana sucrose-phosphate synthase gene expression during fruit ripening.

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

Towards Phosphate Detection in Hydroponics Using Molecularly Imprinted Polymer Sensors.

Science.gov (United States)

Storer, Christopher S; Coldrick, Zachary; Tate, Daniel J; Donoghue, Jack Marsden; Grieve, Bruce

2018-02-10

An interdigitated electrode sensor was designed and microfabricated for measuring the changes in the capacitance of three phosphate selective molecularly imprinted polymer (MIP) formulations, in order to provide hydroponics users with a portable nutrient sensing tool. The MIPs investigated were synthesised using different combinations of the functional monomers methacrylic acid (MAA) and N -allylthiourea, against the template molecules diphenyl phosphate, triethyl phosphate, and trimethyl phosphate. A cross-interference study between phosphate, nitrate, and sulfate was carried out for the MIP materials using an inductance, capacitance, and resistance (LCR) meter. Capacitance measurements were taken by applying an alternating current (AC) with a potential difference of 1 V root mean square (RMS) at a frequency of 1 kHz. The cross-interference study demonstrated a strong binding preference to phosphate over the other nutrient salts tested for each formulation. The size of template molecule and length of the functional monomer side groups also determined that a short chain functional monomer in combination with a template containing large R-groups produced the optimal binding site conditions when synthesising a phosphate selective MIP.

Immobilization of radioactive strontium in contaminated soils by phosphate treatment

International Nuclear Information System (INIS)

Kim, K.H.; Ammons, J.T.

1990-01-01

The feasibility of in situ phosphate- and metal- (calcium, aluminum, and iron) solution treatment for 90 Sr immobilization was investigated. Batch and column experiments were performed to find optimum conditions for coprecipitation of 90 Sr with Ca-, Al-, and Fe-phosphate compounds in contaminated soils. Separate columns were packed with artificially 85 Sr-contaminated acid soil as well as 90 Sr-contaminated soil from the Oak Ridge Reservation. After metal-phosphate treatment, the columns were then leached successively with either tapwater or 0.001 M CaCl 2 solution. Most of the 85 Sr coprecipitated with the metal phosphate compounds. Immobilization of 85 Sr and 90 Sr was affected by such factors as solution pH, metal and phosphate concentration, metal-to-phosphate ratio, and soil characteristics. Equilibration time after treatments also affected 85 Sr immobilization. Many technology aspects still need to be investigated before field applications are feasible, but these experiments indicate that phosphate-based in situ immobilization should prevent groundwater contamination and will be useful as a treatment technology for 90 Sr-contaminated sites. 15 refs., 3 figs., 1 tab

Phosphate-rich sedimentary rocks: significance for organic facies and petroleum exploration

Energy Technology Data Exchange (ETDEWEB)

Waples, D W

1982-03-01

Phosphorus-bearing rocks and sediments can be divided into two genetically distinct classes: phosphatic shales or limestones and phosphorites. Phosphatic shales are primary sediments in which phosphate nodules or micronodules have formed diagenetically by precipitation of calcium phosphates derived mainly from organic phosphorus. The nodules form in reducing environments at shallow depths within the sediments, where loss of phosphate by diffusion to the overlying water column is minimized. Highly biogenic sediments containing large amounts of organic matter and some fine clastic debris provide ideal environments for the formation of phosphate nodules. Phosphorites, in contrast, represent concentrated accumulations of reworked phosphate nodules which originated in phosphatic shales or limestones. Currents, wave action, recrystallization, and erosion and resedimentation are important mechanisms in the concentration process. Phosphatic shales and limestones may become excellent oil source rocks if thermal maturity is achieved. They are useful facies indicators for anoxic or nearly anoxic depositional environments, and are often associated with restricted basins, or, during certain geologic periods, with broad shelves developed during transgressions. Phosphorites, in contrast, are often correlated with sea-level regressions or uplifts. They are modest source rocks because of their low organic carbon contents and the fact that they were reworked under oxidizing conditions. Nevertheless, because phosphorites are derived from, and often grade into, phosphatic shales, they also are of potential utility in the search for oil source beds.

Dental Composites with Calcium / Strontium Phosphates and Polylysine.

Directory of Open Access Journals (Sweden)

Piyaphong Panpisut

Full Text Available This study developed light cured dental composites with added monocalcium phosphate monohydrate (MCPM, tristrontium phosphate (TSrP and antimicrobial polylysine (PLS. The aim was to produce composites that have enhanced water sorption induced expansion, can promote apatite precipitation and release polylysine.Experimental composite formulations consisted of light activated dimethacrylate monomers combined with 80 wt% powder. The powder phase contained a dental glass with and without PLS (2.5 wt% and/or reactive phosphate fillers (15 wt% TSrP and 10 wt% MCPM. The commercial composite, Z250, was used as a control. Monomer conversion and calculated polymerization shrinkage were assessed using FTIR. Subsequent mass or volume changes in water versus simulated body fluid (SBF were quantified using gravimetric studies. These were used, along with Raman and SEM, to assess apatite precipitation on the composite surface. PLS release was determined using UV spectroscopy. Furthermore, biaxial flexural strengths after 24 hours of SBF immersion were obtained.Monomer conversion of the composites decreased upon the addition of phosphate fillers (from 76 to 64% but was always higher than that of Z250 (54%. Phosphate addition increased water sorption induced expansion from 2 to 4% helping to balance the calculated polymerization shrinkage of ~ 3.4%. Phosphate addition promoted apatite precipitation from SBF. Polylysine increased the apatite layer thickness from ~ 10 to 20 μm after 4 weeks. The novel composites showed a burst release of PLS (3.7% followed by diffusion-controlled release irrespective of phosphate addition. PLS and phosphates decreased strength from 154 MPa on average by 17% and 18%, respectively. All formulations, however, had greater strength than the ISO 4049 requirement of > 80 MPa.The addition of MCPM with TSrP promoted hygroscopic expansion, and apatite formation. These properties are expected to help compensate polymerization shrinkage and

Impact of xylose and mannose on central metabolism of yeast Saccharomyces cerevisiae

Energy Technology Data Exchange (ETDEWEB)

Pitkaenen, J.P.

2005-07-01

In this study, understanding of the central metabolism was improved by quantification of metabolite concentrations, enzyme activities, protein abundances, and gene transcript concentrations. Intracellular fluxes were estimated by applying stoichiometric models of metabolism. The methods were applied in the study of yeast Saccharomyces cerevisiae in two separate projects. A xylose project aimed at improved utilization of D- xylose as a substrate for, e.g., producing biomaterial- based fuel ethanol. A mannose project studied the production of GDP-mannose from D-mannose in a strain lacking the gene for phosphomannose isomerase (PMI40 deletion). Hexose, D-glucose is the only sugar more abundant than pentose D-xylose. D-xylose is common in hardwoods (e.g. birch) and crop residues (ca. 25% of dry weight). However, S. cerevisiae is unable to utilize D- xylose without a recombinant pathway where D-xylose is converted to Dxylulose. In this study D-xylose was converted in two steps via xylitol: by D-xylose reductase and xylitol dehydrogenase encoded by XYL1 and XYL2 from Pichia stipitis, respectively. Additionally, endogenous xylulokinase (XKS1) was overexpressed in order to increase the consumption of D-xylose by enhancing the phosphorylation of D-xylulose. Despite of the functional recombinant pathway the utilization rates of D xylose still remained low. This study proposes a set of limitations that are responsible for the low utilization rates of D-xylose under microaerobic conditions. Cells compensated for the cofactor imbalance, caused by the conversion of D-xylose to D- xylulose, by increasing the flux through the oxidative pentose phosphate pathway and by shuttling NADH redox potential to mitochondrion to be oxidized in oxidative phosphorylation. However, mitochondrial NADH inhibits citrate synthase in citric acid cycle, and consequently lower flux through citric acid cycle limits oxidative phosphorylation. Further, limitations in the uptake of D- xylose, in the

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

Effect of submarine groundwater discharge containing phosphate on coral calcification

Science.gov (United States)

Yasumoto, J.; Yasumoto, K.; Iijima, M.; Nozaki, M.; Asai, K.; Yasumoto, M. H.

2017-12-01

It is well known that the anthropogenic eutrophication enriched with various substances including phosphate in coastal waters has resulted in coral degradation. However, to the best of our knowledge, the phosphate threshold value to inhibit the coral calcification has been unclear, due to the unknown mechanisms involved in the inhibition of the calcification by phosphate. In island regions, groundwater is one of the most important clues to transport the nutrients contained in livestock or agricultural wastewaters. However, the actual conditions of coastal pollution with such nutrients have not been understood because of unperceived submarine groundwater discharge (SGD). In this study, to quantify of extremely rapid and localized SGD from Ryukyu limestone aquifer, we investigated the rate and concentration of phosphate of SGD using automated seepage mater in Yoron Island, which is located southern part of Japan. And, to elucidate the inhibition mechanisms for phosphate against coral calcification, we examined its effect on the bottom skeleton formation in primary polyps of Acropora digitifera by using the fluorescence derivatizing reagent having phosphate group (FITC-AA). As a result, the SGD was found to contain 1 to 2 µM of phosphate as much as the concentration in the coastal ground water under agricultural land. Moreover, the amount of phosphate contained in the surface layers of bottom calcareous sands close to the region of SGD were about 5 µmol/g. When the primary polyps were treated with 50 µM of FITC-AA, the bottom skeleton of the primary polyps showed the fluorescence from FITC-AA within a few minutes, suggesting the phosphate binding. Furthermore, when the polyps were treated with 10 µM of FITC-AA, irregular patterns of the elongated skeleton were observed. These results led us to conclude that phosphate is transported via a paracellular pathway to the subcalicoblastic extracellular calcifying medium. These results indicate that the phosphate adsorbed

Unsymmetrical phosphate as extractant for the extraction of nitric acid

International Nuclear Information System (INIS)

Gaikwad, R.H.; Jayaram, R.V.

2016-01-01

Tri-n-butyl phosphate (TBP) was first used as an extractant in 1944, during Manhattan project for the separation of actinides and further explored by Warf in 1949 for the extraction of Ce(IV) from aqueous nitric acid. TBP was further used as an extractant in the Plutonium Uranium Recovery by Extraction (PUREX) process. To meet the stringent requirements of the nuclear industry TBP has been extensively investigated. In spite of its wide applicability, TBP suffers from various disadvantages such as high aqueous solubility, third phase formation, chemical and radiation degradation leading to the formation of undesired products. It also suffers from incomplete decontamination of the actinides from fission products. Various attempts have been made to overcome the problems associated with TBP by way of using higher homologues of TBP such as Tri-iso amyl phosphate (TiAP), Tri-secondary butyl phosphate (TsBP), Tri amyl phosphate (TAP). It was found that in some cases the results were considerably better than those obtained with TBP for uranium/thorium extraction. The extraction of nitric acid by TBP and its higher homologues which are symmetrical are well documented. However, no solvent has emerged clearly superior than TBP. Here in we report the extraction of nitric acid with neutral unsymmetrical phosphates and study them as extractants for the extraction of nitric acid. Dibutyl secbutyl phosphate, dibutyl pentyl phosphate and dibutyl heptyl phosphate were synthesised for this purpose and the extraction of nitric acid was studied in n-dodecane. The results indicate that the substitution of one of the alkyl groups of the symmetrical phosphate adjacent to the phosphoryl (P=O) group of the phosphate does not have any pronounced effect on the extraction capacity of nitric acid. (author)

(13)C metabolic flux analysis in neurons utilizing a model that accounts for hexose phosphate recycling within the pentose phosphate pathway.

Science.gov (United States)

Gebril, Hoda M; Avula, Bharathi; Wang, Yan-Hong; Khan, Ikhlas A; Jekabsons, Mika B

2016-02-01

Glycolysis, mitochondrial substrate oxidation, and the pentose phosphate pathway (PPP) are critical for neuronal bioenergetics and oxidation-reduction homeostasis, but quantitating their fluxes remains challenging, especially when processes such as hexose phosphate (i.e., glucose/fructose-6-phosphate) recycling in the PPP are considered. A hexose phosphate recycling model was developed which exploited the rates of glucose consumption, lactate production, and mitochondrial respiration to infer fluxes through the major glucose consuming pathways of adherent cerebellar granule neurons by replicating [(13)C]lactate labeling from metabolism of [1,2-(13)C2]glucose. Flux calculations were predicated on a steady-state system with reactions having known stoichiometries and carbon atom transitions. Non-oxidative PPP activity and consequent hexose phosphate recycling, as well as pyruvate production by cytoplasmic malic enzyme, were optimized by the model and found to account for 28 ± 2% and 7.7 ± 0.2% of hexose phosphate and pyruvate labeling, respectively. From the resulting fluxes, 52 ± 6% of glucose was metabolized by glycolysis, compared to 19 ± 2% by the combined oxidative/non-oxidative pentose cycle that allows for hexose phosphate recycling, and 29 ± 8% by the combined oxidative PPP/de novo nucleotide synthesis reactions. By extension, 62 ± 6% of glucose was converted to pyruvate, the metabolism of which resulted in 16 ± 1% of glucose oxidized by mitochondria and 46 ± 6% exported as lactate. The results indicate a surprisingly high proportion of glucose utilized by the pentose cycle and the reactions synthesizing nucleotides, and exported as lactate. While the in vitro conditions to which the neurons were exposed (high glucose, no lactate or other exogenous substrates) limit extrapolating these results to the in vivo state, the approach provides a means of assessing a number of metabolic fluxes within the context of hexose phosphate recycling in the PPP from a

The Changes of P-fractions and Solubility of Phosphate Rock in Ultisol Treated by Organic Matter and Phosphate Rock

Directory of Open Access Journals (Sweden)

Heru Bagus Pulunggono

2012-09-01

Full Text Available Phosphorus (P is one of the essential elements for plant, however, its availability is mostly very low in acid soils. It is well documented that application of phosphate rock and organic matter are able to change the level of availability of P-form in acid soils. The objective of the research were to evaluate the changes of P-fractions ( resin-P, NaHCO3-Pi, and NaHCO3-Po and phosphate rock dissolution which were induced by application of organic matter (Imperata cylindrica, Pueraria javanica, dan Colopogonium mucunoides and phosphate rock in Utisol Lampung. The experiment was designed in a completely randomized design with three factors and three replications. The first factor was the types of organic matter (I. cylindrica, P. javanica, and C. mucunoides, the second factor was the rate of organic matter (0, 2.5, and 5%, and the third factor was the rate of phosphate rock (0, 40, and 80 mg P kg-1. The results showed that in the rate of 0 and 1% organic matter, the type of organic matter did not affect P-fraction of NaHCO3-Pi, but in the rate of 2.5 and 5%, NaHCO3-Pi due to application of P. javanica, and C. mucunoides higher than due to application of I. cylindrica. However, the increasing rate of organic matter increased NaHCO3-Pi. Then, P-fraction of Resin-Pi was affected by the type of organic matter, the rate of organic matter, and the rate of phosphate rock, respectively. P-fraction of resin-Pi due to application of P. javanica, and C. mucunoides was higher than due to application of I. cylindrica, but the effect of P. javanica, and C. mucunoides was not different. Increasing the rate of organic matter and phosphate rock increased P-fraction of resin-Pi and NaHCO3-Pi, but P-fraction of NaHCO3-Po was not affected by all treatments. Meanwhile, dissolution of phosphate rock was affected by the kind of organic matter and soil reaction. In the rate of 5% organic matter, dissolution of phosphate rock by application of I. cylindrica (70% was higher

Polyhexamethylene guanidine phosphate aerosol particles induce pulmonary inflammatory and fibrotic responses.

Science.gov (United States)

Kim, Ha Ryong; Lee, Kyuhong; Park, Chang We; Song, Jeong Ah; Shin, Da Young; Park, Yong Joo; Chung, Kyu Hyuck

2016-03-01

Polyhexamethylene guanidine (PHMG) phosphate was used as a disinfectant for the prevention of microorganism growth in humidifiers, without recognizing that a change of exposure route might cause significant health effects. Epidemiological studies reported that the use of humidifier disinfectant containing PHMG-phosphate can provoke pulmonary fibrosis. However, the pulmonary toxicity of PHMG-phosphate aerosol particles is unknown yet. This study aimed to elucidate the toxicological relationship between PHMG-phosphate aerosol particles and pulmonary fibrosis. An in vivo nose-only exposure system and an in vitro air-liquid interface (ALI) co-culture model were applied to confirm whether PHMG-phosphate induces inflammatory and fibrotic responses in the respiratory tract. Seven-week-old male Sprague-Dawley rats were exposed to PHMG-phosphate aerosol particles for 3 weeks and recovered for 3 weeks in a nose-only exposure chamber. In addition, three human lung cells (Calu-3, differentiated THP-1 and HMC-1 cells) were cultured at ALI condition for 12 days and were treated with PHMG-phosphate at set concentrations and times. The reactive oxygen species (ROS) generation, airway barrier injuries and inflammatory and fibrotic responses were evaluated in vivo and in vitro. The rats exposed to PHMG-phosphate aerosol particles in nanometer size showed pulmonary inflammation and fibrosis including inflammatory cytokines and fibronectin mRNA increase, as well as histopathological changes. In addition, PHMG-phosphate triggered the ROS generation, airway barrier injuries and inflammatory responses in a bronchial ALI co-culture model. Those results demonstrated that PHMG-phosphate aerosol particles cause pulmonary inflammatory and fibrotic responses. All features of fibrogenesis by PHMG-phosphate aerosol particles closely resembled the pathology of fibrosis that was reported in epidemiological studies. Finally, we expected that PHMG-phosphate infiltrated into the lungs in the form of

A phosphate transporter from the mycorrhizal fungus Glomus versiforme.

Science.gov (United States)

Harrison, M J; van Buuren, M L

1995-12-07

Vesicular-arbuscular (VA) mycorrhizal fungi form symbiotic associations with the roots of most terrestrial plants, including many agriculturally important crop species. The fungi colonize the cortex of the root to obtain carbon from their plant host, while assisting the plant with the uptake of phosphate and other mineral nutrients from the soil. This association is beneficial to the plant, because phosphate is essential for plant growth and development, especially during growth under nutrient-limiting conditions. Molecular genetic studies of these fungi and their interaction with plants have been limited owing to the obligate symbiotic nature of the VA fungi, so the molecular mechanisms underlying fungal-mediated uptake and translocation of phosphate from the soil to the plant remain unknown. Here we begin to investigate this process by identifying a complementary DNA that encodes a transmembrane phosphate transporter (GvPT) from Glomus versiforme, a VA mycorrhizal fungus. The function of the protein encoded by GvPT was confirmed by complementation of a yeast phosphate transport mutant. Expression of GvPT was localized to the external hyphae of G. versiforme during mycorrhizal associations, these being the initial site of phosphate uptake from the soil.

Iron-phosphate-based chemically bonded phosphate ceramics for mixed waste stabilization

International Nuclear Information System (INIS)

Wagh, A.S.; Jeong, S.Y.; Singh, D.

1997-01-01

In an effort to develop chemically bonded phosphate ceramics for mixed waste stabilization, a collaborative project to develop iron-phosphate based ceramics has been initiated between Argonne National Laboratory and the V. G. Khlopin Radium Institute in St. Petersburg, Russia. The starter powders are oxides of iron that are generated as inexpensive byproduct materials in the iron and steel industry. They contain iron oxides as a mixture of magnetite (Fe 3 O 4 ) and haematite (Fe 2 O 3 ). In this initial phase of this project, both of these compounds were investigated independently. Each was reacted with phosphoric acid solution to form iron phosphate ceramics. In the case of magnetite, the reaction was rapid. Adding ash as the waste component containing hazardous contaminants resulted in a dense and hard ceramic rich in glassy phase. On the other hand, the reaction of phosphoric acid solution with a mixture of haematite and ash waste contaminated with cesium and americium was too slow. Samples had to be molded under pressure. They were cured for 2-3 weeks and then hardened by heating at 350 degrees C for 3 h. The resulting ceramics in both cases were subjected to physical tests for measurement of density, open porosity, compression strength, phase analyses using X-ray diffraction and differential thermal analysis, and leaching tests using toxicity characteristic leaching procedure (TCLP) and ANS 16.1 with 7 days of leaching. Using the preliminary information obtained from these tests, we evaluated these materials for stabilization of Department of Energy's mixed waste streams

Effect of humic substances on the precipitation of calcium phosphate

Institute of Scientific and Technical Information of China (English)

SONG Yong-hui; Hermann H. HAHN; Erhard HOFFMANN; Peter G. WEIDLER

2006-01-01

For phosphorus (P) recovery from wastewater, the effect of humic substances (HS) on the precipitation of calcium phosphate was studied. Batch experiments of calcium phosphate precipitation were undertaken with synthetic water that contained 20 mg/L phosphate (as P) and 20 mg/L HS (as dissolved organic carbon, DOC) at a constant pH value in the range of 8.0-10.0. The concentration variations of phosphate, calcium (Ca) and HS were measured in the precipitation process; the crystalline state and compositions of the precipitates were analysed by powder X-ray diffraction (XRD) and chemical methods, respectively. It showed that at solution pH 8.0, the precipitation rate and removal efficiency of phosphate were greatly reduced by HS, but at solution pH ≥9.0,the effect of HS was very small. The Ca consumption for the precipitation of phosphate increased when HS was added; HS was also removed from solution with the precipitation of calcium phosphate. At solution pH 8.0 and HS concentrations ≤ 3.5 mg/L, and at pH ≥ 9.0 and HS concentrations ≤ 10 mg/L, the final precipitates were proved to be hydroxyapatite (HAP) by XRD. The increases of solution pH value and initial Ca/P ratio helped reduce the influence of HS on the precipitation of phosphate.

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.

Characterization of a thermostable recombinant l-rhamnose isomerase from Caldicellulosiruptor obsidiansis OB47 and its application for the production of l-fructose and l-rhamnulose.

Science.gov (United States)

Chen, Ziwei; Xu, Wei; Zhang, Wenli; Zhang, Tao; Jiang, Bo; Mu, Wanmeng

2018-04-01

l-Hexoses are rare sugars that are important components and precursors in the synthesis of biological compounds and pharmaceutical drugs. l-Rhamnose isomerase (L-RI, EC 5.3.1.14) is an aldose-ketose isomerase that plays a significant role in the production of l-sugars. In this study, a thermostable, l-sugar-producing L-RI from the hyperthermophile Caldicellulosiruptor obsidiansis OB47 was characterized. The recombinant L-RI displayed maximal activity at pH 8.0 and 85 °C and was significantly activated by Co 2+ . It exhibited a relatively high thermostability, with measured half-lives of 24.75, 11.55, 4.15 and 3.30 h in the presence of Co 2+ at 70, 75, 80 and 85 °C, respectively. Specific activities of 277.6, 57.9, 13.7 and 9.6 U mg -1 were measured when l-rhamnose, l-mannose, d-allose and l-fructose were used as substrates, respectively. l-Rhamnulose was produced with conversion ratios of 44.0% and 38.6% from 25 and 50 g L -1 l-rhamnose, respectively. l-Fructose was also efficiently produced by the L-RI, with conversion ratios of 67.0% and 58.4% from 25 and 50 g L -1 l-mannose, respectively. The recombinant L-RI could effectively catalyze the formation of l-rhamnulose and l-fructose, suggesting that it was a promising candidate for industrial production of l-rhamnulose and l-fructose. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Rock phosphate solubilization by the ectomycorrhizal fungus ...

African Journals Online (AJOL)

SAM

2014-06-18

Jun 18, 2014 ... To evaluate phosphate solubilization of ... and MHB had the potential to solubilize these phosphates by decreasing the pH and confirmed that ... Minerals like N, P, K, Ca, S, Zn, Cu and Sr are ... sterile distilled water, chopped, homogenized in 10 ml sterile .... The role of carbon source is important in mineral.

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 ...

Thermochemical investigations on uranyl phosphates and arsenates

International Nuclear Information System (INIS)

Barten, H.

1986-01-01

Results are described of a study of the thermochemical stability of anhydrous phosphates and arsenates. The results of phase studies deal with compound formation and characterization, coexisting phases and limiting physical or chemical properties. The uranyl phosphates evolve oxygen at higher temperatures and the arsenates lose arsenic oxide vapour. These phenomena give the possibility to describe their thermodynamic stabilities. Thus oxygen pressures of uranyl phosphates have been measured using a static, non-isothermal method. Having made available the pure anhydrous compounds in the course of this investigation, molar thermodynamic quantities have been measured as well. These include standard enthalpies of formation from solution calorimetry and high-temperature heat-capacity functions derived from enthalpy increments measured. Some attention is given to compounds with uranium in valencies lower than six which have been met during the investigation. An evaluation is made of the thermodynamics of the compounds studied, to result in tabulized high-temperature thermodynamic functions. Relative stabilities within the systems are discussed and comparisons of the uranyl phosphates and the arsenates are made. (Auth.)

[Tetany secondary to phosphate enema toxicity, case report].

Science.gov (United States)

Núñez Sánchez, María José; Leighton Swaneck, Sofía; Díaz, Franco

2017-06-01

Phosphate enemas are frequently used in the treatment of constipation. Errors in dosage and administration can lead to severe complications. To report a case of severe toxicity of phosphate enemas in a child with no risk factors. 2 years old female, with functional constipation, was brought to emergency department because abdominal pain. She was diagnosed with fecal impaction and received half a bottle of Fleet Adult® (Laboratorio Synthon, Chile) two times, with no clinical resolution, deciding to start proctoclisis in pediatric ward. Soon after admission, she presented painful tetany, but alert and oriented. Patient was transferred to PICU where severe hyperphosphatemia and secondary hypocalcemia were confirmed. Her treatment included electrolyte correction; removal of residual phosphate enema and hyperhydration. Tetany resolved over 2 hours after admission and no other complications. Proctoclisis was performed and patient was discharged three days after admission with pharmacological management of constipation. Phosphate enemas may cause serious complications in children with no risk factors. Errors in dosage, administration and removal of the enema are causes of toxicity in this group. Pediatricians and health personnel must be aware of risks and signs of toxicity of phosphate enema.

Degradation processes of reinforced concretes by combined sulfate–phosphate attack

Energy Technology Data Exchange (ETDEWEB)

Secco, Michele, E-mail: michele.secco@unipd.it [Inter-Departmental Research Center for the Study of Cement Materials and Hydraulic Binders (CIRCe), University of Padova, Via Gradenigo 6, 35131 Padova (Italy); Department of Civil, Environmental and Architectural Engineering (ICEA), University of Padova, Via Marzolo 9, 35131 Padova (Italy); Lampronti, Giulio Isacco, E-mail: gil21@cam.ac.uk [Department of Earth Sciences, University of Cambridge, Downing Street, CB2 3EQ Cambridge (United Kingdom); Schlegel, Moritz-Caspar, E-mail: moritz-caspar.schlegel@helmholtz-berlin.de [BAM Federal Institute for Materials Research and Testing, Unter den Eichen 87, 12205 Berlin (Germany); Helmholtz-Zentrum Berlin fürMaterialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Maritan, Lara, E-mail: lara.maritan@unipd.it [Department of Geosciences, University of Padova, Via Gradenigo 6, 35131 Padova (Italy); Zorzi, Federico, E-mail: federico.zorzi@unipd.it [Department of Geosciences, University of Padova, Via Gradenigo 6, 35131 Padova (Italy)

2015-02-15

A novel form of alteration due to the interaction between hydrated cement phases and sulfate and phosphate-based pollutants is described, through the characterization of concrete samples from an industrial reinforced concrete building. Decalcification of the cement matrices was observed, with secondary sulfate and phosphate-based mineral formation, according to a marked mineralogical and textural zoning. Five alteration layers may be detected: the two outermost layers are characterized by the presence of gypsum–brushite solid solution phases associated with anhydrous calcium sulfates and phosphates, respectively, while a progressive increase in apatite and ammonium magnesium phosphates is observable in the three innermost layers, associated with specific apatite precursors (brushite, octacalcium phosphate and amorphous calcium phosphate, respectively). The heterogeneous microstructural development of secondary phases is related to the chemical, pH and thermal gradients in the attacked cementitious systems, caused by different sources of pollutants and the exposure to the sun's radiation.

Occupational radiation risks in conveyance of bulk phosphate and potash

International Nuclear Information System (INIS)

Grof, Y.; Even, O.; Schlesinger, T.; Margaliot, M.

1996-01-01

The issue of occupational ionizing radiation risks encountered in the conveyance and storage of Phosphates and Potash as loose cargo got very minor attention from the national health and occupational safety authorities in the world. In Israel, the Phosphates include an average 100- 150 ppm of Uranium in equilibrium with its daughters, while in Phosphates produced in most other countries the inaction reaches regularly only few ppm up to 50 ppm. Because of the high content of the Uranium in the Phosphate in Israel we must take into consideration the radiological implications involved in the handling of this mineral. The radiological implications of handling Potash are less significant but can not be neglected as we demonstrate bellow In this presentation we will estimate the occupational radiological risks involved in the storing and transportation of Phosphate and Potash. Note, that the main risk in working with Phosphate and Potash is the risk from the dust itself (authors)

Occupational radiation risks in conveyance of bulk phosphate and potash

Energy Technology Data Exchange (ETDEWEB)

Grof, Y; Even, O; Schlesinger, T; Margaliot, M [Israel Atomic Energy Commission, Yavne (Israel). Soreq Nuclear Research Center

1996-12-01

The issue of occupational ionizing radiation risks encountered in the conveyance and storage of Phosphates and Potash as loose cargo got very minor attention from the national health and occupational safety authorities in the world. In Israel, the Phosphates include an average 100- 150 ppm of Uranium in equilibrium with its daughters, while in Phosphates produced in most other countries the inaction reaches regularly only few ppm up to 50 ppm. Because of the high content of the Uranium in the Phosphate in Israel we must take into consideration the radiological implications involved in the handling of this mineral. The radiological implications of handling Potash are less significant but can not be neglected as we demonstrate bellow In this presentation we will estimate the occupational radiological risks involved in the storing and transportation of Phosphate and Potash. Note, that the main risk in working with Phosphate and Potash is the risk from the dust itself (authors).

Reducing the cadmium content of crude phosphates and mineral fertilizers

Energy Technology Data Exchange (ETDEWEB)

Plessen, H von; Schimmel, G

1987-10-01

Crude sedimentary phosphates generally contain cadmium together with traces of other heavy metals. These Cd traces generally end up in fertilizers produced from the crude phosphates. Processes have therefore been developed to separate the Cd from the crude phosphate or from the crude phosphoric acids arising therefrom as intermediates. In this way, the Cd content of the crude phosphate can be reduced to less the 10% of its original value, and to 50% thereof by extractive treatment with acidic calcium nitrate solution. Older calcination processes for crude phosphate have been improved to give residual Cd contents of 10 to 50% at temperatures of 800 to 1000/sup 0/C. Cadmium can be removed almost quantitatively from crude phosphate by means of dialkyl dithiophosphoric acid esters by extraction, binding to adsorbents, or ion flotation. Cadmium can be extracted from crude acids in high yield by long-chained amines. After partial neutralization of the crude acids, precipitation as cadmium sulphide is also possible.

Degradation processes of reinforced concretes by combined sulfate–phosphate attack

International Nuclear Information System (INIS)

Secco, Michele; Lampronti, Giulio Isacco; Schlegel, Moritz-Caspar; Maritan, Lara; Zorzi, Federico

2015-01-01

A novel form of alteration due to the interaction between hydrated cement phases and sulfate and phosphate-based pollutants is described, through the characterization of concrete samples from an industrial reinforced concrete building. Decalcification of the cement matrices was observed, with secondary sulfate and phosphate-based mineral formation, according to a marked mineralogical and textural zoning. Five alteration layers may be detected: the two outermost layers are characterized by the presence of gypsum–brushite solid solution phases associated with anhydrous calcium sulfates and phosphates, respectively, while a progressive increase in apatite and ammonium magnesium phosphates is observable in the three innermost layers, associated with specific apatite precursors (brushite, octacalcium phosphate and amorphous calcium phosphate, respectively). The heterogeneous microstructural development of secondary phases is related to the chemical, pH and thermal gradients in the attacked cementitious systems, caused by different sources of pollutants and the exposure to the sun's radiation

Calcium-phosphate-osteopontin particles for caries control

DEFF Research Database (Denmark)

Schlafer, Sebastian; Birkedal, Henrik; Olsen, Jakob

2016-01-01

Caries is caused by acid production in biofilms on dental surfaces. Preventing caries therefore involves control of microorganisms and/or the acid produced. Here, calcium-phosphate-osteopontin particles are presented as a new approach to caries control. The particles are made by co......-precipitation and designed to bind to bacteria in biofilms, impede biofilm build-up without killing the microflora, and release phosphate ions to buffer bacterial acid production if the pH decreases below 6. Analysis of biofilm formation and pH in a five-species biofilm model for dental caries showed that treatment......H always remained above 5.5. Hence, calcium-phosphate-osteopontin particles show potential for applications in caries control....

Determination of carbon-reduction-cycle intermediates in leaves of Arbutus unedo L. suffering depressions in photosynthesis after application of abscisic acid or exposure to dry air.

Science.gov (United States)

Loske, D; Raschke, K

1988-02-01

Gas exchange and contents of photosynthetic intermediates of leaves of Arbutus unedo L. were determined with the aim of recognizing the mechanisms of inhibition that were responsible for the "midday depression" of photosynthesis following exposure to dry air, and the decline in photosynthetic capacity following application of abscisic acid (ABA). Rapidly killed (<0.1 s) leaf samples were taken when gas analysis showed reduced CO2 assimilation. Determination of the contents of 3-phosphoglyceric acid (PGA), ribulose 1,5-bisphosphate (RuBP), triose phosphates, fructose 1,6-bisphosphate and hexose phosphates in the samples showed that significant variation occurred only in the level of PGA. As a result, the ratio PGA/RuBP decreased with increasing inhibition of photosynthesis, particularly when application of ABA had been the cause. A comparison of metabolite patterns did not bring out qualitative differences that would have indicated that effects of ABA and of dry air had been caused by separate mechanisms. Depression of photosynthesis occurred in the presence of sufficient RuBP which indicated that the carboxylation reaction of the carbon-reduction-cycle was inhibited after application of ABA or exposure to dry air.

Iron phosphate materials as cathodes for lithium batteries

CERN Document Server

Prosini, Pier Paolo

2011-01-01

""Iron Phosphate Materials as Cathodes for Lithium Batteries"" describes the synthesis and the chemical-physical characteristics of iron phosphates, and presents methods of making LiFePO4 a suitable cathode material for lithium-ion batteries. The author studies carbon's ability to increase conductivity and to decrease material grain size, as well as investigating the electrochemical behaviour of the materials obtained. ""Iron Phosphate Materials as Cathodes for Lithium Batteries"" also proposes a model to explain lithium insertion/extraction in LiFePO4 and to predict voltage profiles at variou

Regulation of dual glycolytic pathways for fructose metabolism in heterofermentative Lactobacillus panis PM1.

Science.gov (United States)

Kang, Tae Sun; Korber, Darren R; Tanaka, Takuji

2013-12-01

Lactobacillus panis PM1 belongs to the group III heterofermentative lactobacilli that use the 6-phosphogluconate/phosphoketolase (6-PG/PK) pathway as their central metabolic pathway and are reportedly unable to grow on fructose as a sole carbon source. We isolated a variant PM1 strain capable of sporadic growth on fructose medium and observed its distinctive characteristics of fructose metabolism. The end product pattern was different from what is expected in typical group III lactobacilli using the 6-PG/PK pathway (i.e., more lactate, less acetate, and no mannitol). In addition, in silico analysis revealed the presence of genes encoding most of critical enzymes in the Embden-Meyerhof (EM) pathway. These observations indicated that fructose was metabolized via two pathways. Fructose metabolism in the PM1 strain was influenced by the activities of two enzymes, triosephosphate isomerase (TPI) and glucose 6-phosphate isomerase (PGI). A lack of TPI resulted in the intracellular accumulation of dihydroxyacetone phosphate (DHAP) in PM1, the toxicity of which caused early growth cessation during fructose fermentation. The activity of PGI was enhanced by the presence of glyceraldehyde 3-phosphate (GAP), which allowed additional fructose to enter into the 6-PG/PK pathway to avoid toxicity by DHAP. Exogenous TPI gene expression shifted fructose metabolism from heterolactic to homolactic fermentation, indicating that TPI enabled the PM1 strain to mainly use the EM pathway for fructose fermentation. These findings clearly demonstrate that the balance in the accumulation of GAP and DHAP determines the fate of fructose metabolism and the activity of TPI plays a critical role during fructose fermentation via the EM pathway in L. panis PM1.

21 CFR 184.1697 - Riboflavin-5′-phosphate (sodium).

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Riboflavin-5â²-phosphate (sodium). 184.1697 Section... SAFE Listing of Specific Substances Affirmed as GRAS § 184.1697 Riboflavin-5′-phosphate (sodium). (a) Riboflavin-5′-phosphate (sodium) (C17H20N4O9PNa·2H2O, CAS Reg. No 130-40-5) occurs as the dihydrate in yellow...

40 CFR 422.40 - Applicability; description of the defluorinated phosphate rock subcategory.

Science.gov (United States)

2010-07-01

... defluorinated phosphate rock subcategory. 422.40 Section 422.40 Protection of Environment ENVIRONMENTAL... Defluorinated Phosphate Rock Subcategory § 422.40 Applicability; description of the defluorinated phosphate rock... phosphate rock by application of high temperature treatment along with wet process phosphoric acid, silica...

Structural basis for phosphatidylinositol-phosphate biosynthesis

Science.gov (United States)

Clarke, Oliver B.; Tomasek, David; Jorge, Carla D.; Dufrisne, Meagan Belcher; Kim, Minah; Banerjee, Surajit; Rajashankar, Kanagalaghatta R.; Shapiro, Lawrence; Hendrickson, Wayne A.; Santos, Helena; Mancia, Filippo

2015-10-01

Phosphatidylinositol is critical for intracellular signalling and anchoring of carbohydrates and proteins to outer cellular membranes. The defining step in phosphatidylinositol biosynthesis is catalysed by CDP-alcohol phosphotransferases, transmembrane enzymes that use CDP-diacylglycerol as donor substrate for this reaction, and either inositol in eukaryotes or inositol phosphate in prokaryotes as the acceptor alcohol. Here we report the structures of a related enzyme, the phosphatidylinositol-phosphate synthase from Renibacterium salmoninarum, with and without bound CDP-diacylglycerol to 3.6 and 2.5 Å resolution, respectively. These structures reveal the location of the acceptor site, and the molecular determinants of substrate specificity and catalysis. Functional characterization of the 40%-identical ortholog from Mycobacterium tuberculosis, a potential target for the development of novel anti-tuberculosis drugs, supports the proposed mechanism of substrate binding and catalysis. This work therefore provides a structural and functional framework to understand the mechanism of phosphatidylinositol-phosphate biosynthesis.

Phosphate Phosphors for Solid-State Lighting

CERN Document Server

Shinde, Kartik N; Swart, H C; Park, Kyeongsoon

2012-01-01

The idea for this book arose out of the realization that, although excellent surveys and a phosphor handbook are available, there is no single source covering the area of phosphate based phosphors especially for lamp industry. Moreover, as this field gets only limited attention in most general books on luminescence, there is a clear need for a book in which attention is specifically directed toward this rapidly growing field of solid state lighting and its many applications. This book is aimed at providing a sound introduction to the synthesis and optical characterization of phosphate phosphor for undergraduate and graduate students as well as teachers and researchers. The book provides guidance through the multidisciplinary field of solid state lighting specially phosphate phosphors for beginners, scientists and engineers from universities, research organizations, and especially industry. In order to make it useful for a wide audience, both fundamentals and applications are discussed, together.

Biosolubilization of poorly soluble rock phosphates by Aspergillus tubingensis and Aspergillus niger

Energy Technology Data Exchange (ETDEWEB)

Reddy, M.S.; Kumar, S.; Babita, K. [Thapar Institute of Engineering and Technology, Patiala (India). School of Biotechnology; Reddy, M.S. [Auburn University, AL (United States). Department of Entomology and Plant Pathology

2002-09-01

Three isolates of Aspergillus tubingensis and two isolates of Aspergillus niger isolated from rhizospheric soils were tested on solubilization of different rock phosphates. All the isolates of Aspergillus were capable of solubilizing all the natural rock phosphates. A. tubingensis (AT1) showed maximum percent solubilization in all the rock phosphates tested in this study when compared to other isolates. This isolate also showed highest phosphorus (P) solubilization when grown in the presence of 2% of rock phosphate. A. tubingensis (AT1) seems to be more efficient in solubilization of rock phosphates compared to other isolates reported elsewhere. This is the first report of rock phosphate solubilization by A. tubingensis and might provide an efficient large scale biosolubilization of rock phosphates intended for P fertilizer. (author)

Comparative analysis of inflamed and non-inflamed colon biopsies reveals strong proteomic inflammation profile in patients with ulcerative colitis

DEFF Research Database (Denmark)

Poulsen, Nina Aagaard; Andersen, Vibeke; Moller, Jens Christian

2012-01-01

colonic biopsies were characterized using 2D-gel electrophoresis, and peptide mass fingerprinting using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was applied for identification of differently expressed protein spots. Results: A total of 597 spots were...... mucosa with acute UC is strong. Totally, 43 individual protein spots were identified, including proteins involved in energy metabolism (triosephosphate isomerase, glycerol-3-phosphate-dehydrogenase, alpha enolase and L-lactate dehydrogenase B-chain) and in oxidative stress (superoxide dismutase...

The radiological impact of the Belgian phosphate industry

Energy Technology Data Exchange (ETDEWEB)

Vanmarcke, H.; Paridaens, J. [Belgian Nuclear Research Centre, SCK.CEN, Boeretang 200, 2400 Mol (Belgium)

2006-07-01

The Belgian phosphate industry processes huge amounts of phosphate ore (1.5 to 2 Mton/year) for a wide range of applications, the most important being the production of phosphoric acid, fertilizers and cattle food. Marine phosphate ores show high specific activities of the natural uranium decay series (usually indicated by Ra-226) (e.g. 1200 to 1500 Bq/kg for Moroccan ore). Ores of magmatic origin generally contain less of the uranium and more of the thorium decay series (up to 500 Bq/kg). These radionuclides turn up in by-products, residues or product streams depending on the processing method and the acid used for the acidulation of the phosphate rock. Sulfuric acid is the most widely used, but also hydrochloric acid and nitric acid are applied in Belgium. For Flanders, the northern part of Belgium, we already have a clear idea of the production processes and waste streams. The five Flemish phosphate plants, from 1920 to 2000, handled 54 million ton of phosphate ore containing 65 TBq of radium-226 and 2.7 TBq of thorium- 232. The total surface area of the phosphogypsum and calcium fluoride sludge deposits amounts to almost 300 ha. There is also environmental contamination along two small rivers receiving the waste waters of the hydrochloric production process: the Winterbeek (> 200 ha) and the Grote Laak (12 ha). The data on the impact of the phosphate industry in the Walloon provinces in Belgium is less complete. A large plant produced in 2004 0.8 Mton of phosphogypsum, valorizing about 70 % of the gypsum in building materials (plaster, cement), in fertilizers, and in other products such as paper. The remainder was stored on a local disposal site. The radiological impact of the Belgian phosphate industry on the local population will be discussed. At present most contaminated areas are still recognizable as waste deposits and inaccessible to the population. However as gypsum deposits and other contaminated areas quickly blend in with the landscape, it is

Volumetric, acoustic and viscometric behaviour of dipotassium hydrogen phosphate and disodium hydrogen phosphate in aqueous solution of N-acetyl glycine at different temperatures

International Nuclear Information System (INIS)

Kumar, Harsh; Singla, Meenu; Mittal, Heena

2016-01-01

Highlights: • Densities, speeds of sound, viscosities of phosphate salts in aqueous N-acetyl glycine. • Large values of partial molar volume for dipotassium hydrogen phosphate. • Partial molar volume of transfer are positive for phosphate salts. • Positive B-coefficient values indicate ion–solvent interactions. - Abstract: Densities, speeds of sound and viscosities of dipotassium hydrogen phosphate (DPHP) and disodium hydrogen phosphate (DSHP) in aqueous solutions of N-acetyl glycine (AcGly) are reported at different temperatures. Densities and speeds of sound have been used to calculate apparent molar volume, apparent molar isentropic compression, partial molar volume, partial molar isentropic compression, partial molar volume of transfer, partial molar isentropic compression of transfer and partial molar expansivity. Pair and triplet interaction coefficients have also been calculated. Experimental viscosities have been used to determine B-coefficients. Further pair and triplet interaction coefficients have also been calculated. The results are discussed in terms of solute–solvent interactions.

Preferable adsorption of phosphate using lanthanum-incorporated porous zeolite: Characteristics and mechanism

Science.gov (United States)

He, Yinhai; Lin, Hai; Dong, Yingbo; Wang, Liang

2017-12-01

The adsorbent, where lanthanum oxide was incorporated onto porous zeolite (La-Z), of preferable adsorption towards phosphate was prepared by hydrothermal synthesis. Based on pH effect results, La-Z would effectively sequestrate phosphate over wider pH range of 3.0-7.0, alkaline conditions were unfavorable for phosphate. The adsorption of phosphate was not significantly influenced by ionic strength and by coexisting anions of chloride, nitrate and sulfate but bicarbonate showed slightly greater negative effects, indicating La-Z possessed highly selectivity to phosphate. Adsorption of phosphate could be well fitted by pseudo-second-order model and the process was mainly controlled by intra-particle diffusion. Equilibrium adsorption demonstrated that Langmuir model was more suitable than Freundlich model for description phosphate adsorption and the adsorption capacity was 17.2 mg P g-1, which exhibited 95% utilization of incorporated La. Over 95% phosphate was eliminated in real effluent treatment when the dose was 2 g L-1. The underlying mechanism for phosphate capture was probed with Zeta potential and X-ray photoelectron spectroscope analysis, and the formation of La-P inner-sphere complexation was testified to be the dominant pathway. All the results suggested that the porous zeolite-supported lanthanum oxide can serve as a promising adsorbent for phosphate removal in realistic application.

Synthesis and Characterization of Metal Phosphates for Photocatalytic Applications

KAUST Repository

Al-Sabban, Bedour

2012-07-01

Solar energy is the most abundant efficient and important source of renewable energy. The objective of this study is to develop highly efficient visible light responsive photocatalysts for overall water splitting. This is done by using silver or copper containing materials. Phosphate compounds have caught much attention due to their rigid structure, thermal stability and resistance to chemical attacks. Solid phosphates can be prepared by direct solid-state reaction between metal cations and phosphate anions at high temperatures. Double metal phosphates of the Nasion-type structure had shown further technological importance. It has been reported that well-crystallized double metal phosphate particles have excellent ordering and cationic conduction channels in the Nasicon framework. In this study, several Nasion-type structured materials have been synthesized by solid-state method (e.g. CuTi2(PO4)3 and AgTi2(PO4)3) heated up under different temperatures (400–1100C) in N2 or air atmosphere. These materials were characterized by XRD, SEM, DR-UV-Vis spectroscopy and tested for photocatalytic applications. A new method for direct synthesis of photoelectrode on Ti Plate had been demonstrated. Further investigations on controlling the size and morphology for better performance of single and double metal phosphates will be done.

Effect of Phosphate levels on vegetables irrigated with wastewater

Science.gov (United States)

Oladeji, S. O.; Saeed, M. D.

2018-04-01

This study examined accumulation of phosphate ions in wastewater and vegetables through man-made activities. Phosphate level was determined in wastewater and vegetables collected on seasonal basis along Kubanni stream in Zaria using UV/Visible and Smart Spectro Spectrophotometers for their analyses. Results obtained show that phosphate concentrations ranged from 3.85 – 42.33 mg/L in the first year and 15.60 – 72.80 mg/L in the second year for wastewater whereas the vegetable had levels of 3.80 – 23.65 mg/kg in the year I and 7.48 – 27.15 mg/kg in the year II. Further statistical tests indicated no significant difference in phosphate levels across the locations and seasons for wastewater and vegetables evaluated. Correlation results for these two years indicated negative (r = -0.062) relationship for wastewater while low (r = 0.339) relationship noticed for vegetables planted in year I to that of year II. Phosphate concentrations obtained in this study was higher than Maximum Contaminant Levels set by Standard Organization such as WHO and FAO for wastewater whereas vegetables of the sampling sites were not contaminated with phosphate ions. Irrigating farmland with untreated wastewater has negative consequence on the crops grown with it.

Metal Phosphides and Phosphates-based Electrodes for Electrochemical Supercapacitors.

Science.gov (United States)

Li, Xin; Elshahawy, Abdelnaby M; Guan, Cao; Wang, John

2017-10-01

Phosphorus compounds, such as metal phosphides and phosphates have shown excellent performances and great potential in electrochemical energy storage, which are demonstrated by research works published in recent years. Some of these metal phosphides and phosphates and their hybrids compare favorably with transition metal oxides/hydroxides, which have been studied extensively as a class of electrode materials for supercapacitor applications, where they have limitations in terms of electrical and ion conductivity and device stability. To be specific, metal phosphides have both metalloid characteristics and good electric conductivity. For metal phosphates, the open-framework structures with large channels and cavities endow them with good ion conductivity and charge storage capacity. In this review, we present the recent progress on metal phosphides and phosphates, by focusing on their advantages/disadvantages and potential applications as a new class of electrode materials in supercapacitors. The synthesis methods to prepare these metal phosphides/phosphates are looked into, together with the scientific insights involved, as they strongly affect the electrochemical energy storage performance. Particular attentions are paid to those hybrid-type materials, where strong synergistic effects exist. In the summary, the future perspectives and challenges for the metal phosphides, phosphates and hybrid-types are proposed and discussed. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A chalcone isomerase-like protein enhances flavonoid production and flower pigmentation.

Science.gov (United States)

Morita, Yasumasa; Takagi, Kyoko; Fukuchi-Mizutani, Masako; Ishiguro, Kanako; Tanaka, Yoshikazu; Nitasaka, Eiji; Nakayama, Masayoshi; Saito, Norio; Kagami, Takashi; Hoshino, Atsushi; Iida, Shigeru

2014-04-01

Flavonoids are major pigments in plants, and their biosynthetic pathway is one of the best-studied metabolic pathways. Here we have identified three mutations within a gene that result in pale-colored flowers in the Japanese morning glory (Ipomoea nil). As the mutations lead to a reduction of the colorless flavonoid compound flavonol as well as of anthocyanins in the flower petal, the identified gene was designated enhancer of flavonoid production (EFP). EFP encodes a chalcone isomerase (CHI)-related protein classified as a type IV CHI protein. CHI is the second committed enzyme of the flavonoid biosynthetic pathway, but type IV CHI proteins are thought to lack CHI enzymatic activity, and their functions remain unknown. The spatio-temporal expression of EFP and structural genes encoding enzymes that produce flavonoids is very similar. Expression of both EFP and the structural genes is coordinately promoted by genes encoding R2R3-MYB and WD40 family proteins. The EFP gene is widely distributed in land plants, and RNAi knockdown mutants of the EFP homologs in petunia (Petunia hybrida) and torenia (Torenia hybrida) had pale-colored flowers and low amounts of anthocyanins. The flavonol and flavone contents in the knockdown petunia and torenia flowers, respectively, were also significantly decreased, suggesting that the EFP protein contributes in early step(s) of the flavonoid biosynthetic pathway to ensure production of flavonoid compounds. From these results, we conclude that EFP is an enhancer of flavonoid production and flower pigmentation, and its function is conserved among diverse land plant species. © 2014 The Authors The Plant Journal © 2014 John Wiley & Sons Ltd.

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.

Biodegradation of tert-butylphenyl diphenyl phosphate

International Nuclear Information System (INIS)

Heitkamp, M.A.; Freeman, J.P.; Cerniglia, C.E.

1986-01-01

The biodegradation of tert-butylphenyl diphenyl phosphate (BPDP) was examined in microcosms containing sediment and water from five different ecosystems as part of studies to elucidate the environmental fate of phosphate ester flame retardants. Biodegradation of [ 14 C]BPDP was monitored in the environmental microcosms by measuring the evolution of 14 CO 2 . Over 37% of BPDP was mineralized after 8 weeks in microcosms from an ecosystem which had chronic exposure to agricultural chemicals. In contrast, only 1.7% of BPDP was degraded to 14 CO 2 in samples collected from a noncontaminated site. The exposure concentration of BPDP affected the percentage which was degraded to 14 CO 2 in microcosms from the two most active ecosystems. Mineralization was highest at a concentration of 0.1 mg of BPDP and was inhibited with 10- and 100-fold higher concentrations of BPDP. The authors observed adaptive increases in both microbial populations and phosphoesterase enzymes in some sediments acclimated to BPDP. Chemical analyses of the residues in the microcosms indicated undegraded BPDP and minor amounts of phenol, tert-butylphenol, diphenyl phosphate, and triphenyl phosphate as biodegradation products. These data suggest that the microbial degradation of BPDP results from at least three catabolic processes and is highest when low concentrations of BPDP are exposed to sediment microorganisms of eutrophic ecosystems which have high phosphotri- and diesterase activities and previous exposure to anthropogenic chemicals

Immobilization of transition metal ions on zirconium phosphate monolayers

International Nuclear Information System (INIS)

Melezhik, A.V.; Brej, V.V.

1998-01-01

It is shown that ions of transition metals (copper, iron, vanadyl, titanium) are adsorbed on zirconium phosphate monolayers. The zirconium phosphate threshold capacity corresponds to substitution of all protons of hydroxyphosphate groups by equivalent amounts of copper, iron or vanadyl. Adsorption of polynuclear ions is possible in case of titanium. The layered substance with specific surface up to 300 m 2 /g, wherein ultradispersed titanium dioxide particles are intercalirated between zirconium-phosphate layers, is synthesized

Effect of humic acid preloading on phosphate adsorption onto zirconium-modified zeolite.

Science.gov (United States)

Lin, Jianwei; Zhang, Zhe; Zhan, Yanhui

2017-05-01

A zirconium-modified zeolite (ZrMZ) was prepared, and then, humic acid (HA) was immobilized on the ZrMZ surface to prepare HA-loaded ZrMZ (HA-ZrMZ). The obtained ZrMZ and HA-ZrMZ were characterized by energy dispersive X-ray spectroscopy, elemental analyzer, N 2 adsorption/desorption isotherms, pH at the point of zero charge, and X-ray photoelectron spectroscopy. The adsorption characteristics of phosphate on ZrMZ and HA-ZrMZ were comparatively investigated in batch mode. The adsorption mechanism of phosphate on ZrMZ and HA-ZrMZ was investigated by ionic strength effect and 31 P nuclear magnetic resonance. The mechanism for phosphate adsorption onto ZrMZ was the formation of inner-sphere phosphate complexes at the solid/solution interface. The preloading of HA on ZrMZ reduced the phosphate adsorption capacity, and the more the HA loading amount, the lower the phosphate adsorption capacity. However, the preloading of HA on ZrMZ did not change the phosphate adsorption mechanism; i.e., the formation of inner-sphere phosphate surface complexes was still responsible for the adsorption of phosphate on HA-ZrMZ. The decreased phosphate adsorption capacity for ZrMZ after HA coating could be attributed to the fact that the coating of HA on ZrMZ reduced the amount of binding active sites available for phosphate adsorption, changed the adsorbent surface charges, and reduced the specific surface areas and pore volumes of ZrMZ.

[Screening of food-grade microorganisms for biotransformation of D-tagatose and cloning and expression of L-arabinose isomerase].

Science.gov (United States)

Men, Yan; Zhu, Yueming; Guan, Yuping; Zhang, Tongcun; Izumori, Ken; Sun, Yuanxia

2012-05-01

L-Arabinose isomerase (L-AI) is an intracellular enzyme that catalyzes the reversible isomerization of D-galactose and D-tagatose. Given the widespread use of D-tagatose in the food industry, food-grade microorganisms and the derivation of L-AI for the production of D-tagatose is gaining increased attention. In the current study, food-grade strains from different foods that can convert D-galactose to D-tagatose were screened. According to physiological, biochemical, and 16S rDNA gene analyses, the selected strain was found to share 99% identity with Pediococcus pentosaceus, and was named as Pediococcus pentosaceus PC-5. The araA gene encoding L-AI from Pediococcus pentosaceus PC-5 was cloned and overexpressed in E. coli BL21. The yield of D-tagatose using D-galactose as the substrate catalyzed by the crude enzyme in the presence of Mn2+ was found to be 33% at 40 degrees C.

Multivariate statistical analysis of radioactive variables in two phosphate ores from Sudan

International Nuclear Information System (INIS)

Adam, Abdel Majid A.; Eltayeb, Mohamed Ahmed H.

2012-01-01

Multivariate statistical techniques are efficient ways to display complex relationships among many objects. An attempt was made to study the radioactive data in two types of Sudanese phosphate deposits; Kurun and Uro phosphate, using several multivariate statistical methods. Pearson correlation coefficient revealed that a U-238 distribution in Kurun phosphate is controlled by the variation of K-40 concentration, whereas in Uro phosphate it is controlled by the variation of U-235 and U-234 concentration. Histograms and normal Q–Q plots clearly show that the radioactive variables did not follow a normal distribution. This non-normality feature observed may be attributed to complicating influence of geological factors. The principal components analysis (PCA) gives a model of five components for representing the acquired data from Kurun phosphate, where 89.5% of the total variance is explained. A model of four components was sufficient to represent the acquired data from Uro phosphate, where 87.5% of the total data variance is explained. The hierarchical cluster analysis (HCA) indicates that U-238 behaves in the same manner in the two types of phosphates; it associated with a group of four radionuclides; U-234, Po-210, Ra-226, Th-230, which the most abundant radionuclides, and all belong to the uranium-238 decay series. Two parameters have been adapted for the direct differentiate between the two phosphates. Firstly, U-238 in Uro phosphate have shown higher degree of mobility (CV% = 82.6) than that in Kurun phosphate (CV% = 64.7), and secondly, the activity ratio of Th-230/Th-232 in Uro phosphate is nine times than that in Kurun phosphate. - Highlights: ► Multivariate statistical techniques were used to characterize radioactive data. ► U-238 in Uro phosphate shows higher degree of mobility (CV% = 82.6). ► U-238 in Kurun phosphate shows lower degree of mobility (CV% = 64.7). ► The radioactive variables did not follow a normal distribution. ► The ratio of Th

Preparation of Edible Corn Starch Phosphate with Highly Reactive ...

African Journals Online (AJOL)

1Food & Bioengineering Department, Henan University of Science and Technology, Luoyang, Henan 471003 ... Purpose: To prepare edible corn starch phosphate under optimized experimental conditions. ... In food industry, starch phosphate.

Characterisation of Phosphate Accumulating Organisms and Techniques for Polyphosphate Detection: A Review

Directory of Open Access Journals (Sweden)

Cédric Tarayre

2016-05-01

Full Text Available Phosphate minerals have long been used for the production of phosphorus-based chemicals used in many economic sectors. However, these resources are not renewable and the natural phosphate stocks are decreasing. In this context, the research of new phosphate sources has become necessary. Many types of wastes contain non-negligible phosphate concentrations, such as wastewater. In wastewater treatment plants, phosphorus is eliminated by physicochemical and/or biological techniques. In this latter case, a specific microbiota, phosphate accumulating organisms (PAOs, accumulates phosphate as polyphosphate. This molecule can be considered as an alternative phosphate source, and is directly extracted from wastewater generated by human activities. This review focuses on the techniques which can be applied to enrich and try to isolate these PAOs, and to detect the presence of polyphosphate in microbial cells.

Sorption of phosphate onto calcite; results from batch experiments and surface complexation modeling

DEFF Research Database (Denmark)

Sø, Helle Ugilt; Postma, Dieke; Jakobsen, Rasmus

2011-01-01

The adsorption of phosphate onto calcite was studied in a series of batch experiments. To avoid the precipitation of phosphate-containing minerals the experiments were conducted using a short reaction time (3h) and low concentrations of phosphate (⩽50μM). Sorption of phosphate on calcite was stud......The adsorption of phosphate onto calcite was studied in a series of batch experiments. To avoid the precipitation of phosphate-containing minerals the experiments were conducted using a short reaction time (3h) and low concentrations of phosphate (⩽50μM). Sorption of phosphate on calcite...... of a high degree of super-saturation with respect to hydroxyapatite (SIHAP⩽7.83). The amount of phosphate adsorbed varied with the solution composition, in particular, adsorption increases as the CO32- activity decreases (at constant pH) and as pH increases (at constant CO32- activity). The primary effect...... of ionic strength on phosphate sorption onto calcite is its influence on the activity of the different aqueous phosphate species. The experimental results were modeled satisfactorily using the constant capacitance model with >CaPO4Ca0 and either >CaHPO4Ca+ or >CaHPO4- as the adsorbed surface species...

Engineering potato starch with a higher phosphate content

NARCIS (Netherlands)

Xu, Xuan; Huang, Xing Feng; Visser, Richard G.F.; Trindade, Luisa M.

2017-01-01

Phosphate esters are responsible for valuable and unique functionalities of starch for industrial applications. Also in the cell phosphate esters play a role in starch metabolism, which so far has not been well characterized in storage starch. Laforin, a human enzyme composed of a

Development of a fully injectable calcium phosphate cement

Indian Academy of Sciences (India)

Permanent link: https://www.ias.ac.in/article/fulltext/boms/026/04/0415-0422. Keywords. Calcium phosphate cements; hydroxyapatite; bioceramics; bone substitute; orthopedic; dental. Abstract. A study on the development of a fully injectable calcium phosphate cement for orthopedic and dental applications is presented.

Mineral phosphate solubilizing bacterial community in agro-ecosystem

African Journals Online (AJOL)

Mineral phosphate solubilizing bacterial community in agro-ecosystem. N Saha, S Biswas. Abstract. The present communication deals with the assessment of phosphate solubilizing bacterial community structure across artificially created fertility gradient with regards to N, P and K status of soil in the experimental site.

Potential for phosphate mitigation from agricultural runoff by three aquatic macrophytes

Science.gov (United States)

Phosphate from agricultural runoff is considered a contributor to eutrophication. Three aquatic macrophyte species, Leersia oryzoides, Typha latifolia, and Sparganium americanum, were investigated for their phosphate mitigation ability. Mesocosms were exposed to flowing phosphate enriched water (1...

Investigation of calcium phosphate coatings for biomedical applications

International Nuclear Information System (INIS)

Yusof Abdullah; Idris Besar; Muhammad Jamal Md Isa; Mohamad Abd Razak; Hyzan Mohd Yusof

1999-01-01

Calcium phosphate is the main constituent of our bone and tooth minerals. The use of this bioactive material for coating implant such as artificial joint prosthesis, therefore, can promote biological fixation and enhance biocompatibility. Our initial work has been focused on the evaluation of experimental conditions of coating preparation and the effects of post-deposition calcium phosphate coatings on stainless steel substrates. The coating layers were produced by the precipitation technique and coatings were carried out in sol-gel by the dipping method. For comparison purposes a wet method was used to obtain a fine calcium phosphate ceramic powder for fabrication of microcrystal suspension used as a coating material. Scanning electron microscopy (SEM), energy dispersive microanalysis (EDS), energy dispersive x-ray fluorescence (EDXRF) and x-ray diffraction (XRD) were used to characterise the morphology, chemical composition and structure of the coatings. The results showed that the dip coating of stainless steel substrates using viscous solutions lead to the formation of porous calcium phosphate layers. These results suggested that fabrication of bioactive calcium phosphate coatings using this route offers significant advantages over the currently used methods due to considerably lower temperature process involved and may produce better result for substrates with complex shapes

Lar mountain phosphate ore processing using flotation approach

International Nuclear Information System (INIS)

Gharabaghi, M.; Noaparast, M.; Shafaei Tonkaboni, S. Z.

2007-01-01

The sample of Lar Mountain Phosphate deposit which is located in the southwest of Iran, was studied to upgrade its phosphate grade. The results obtained from mineralogical studies showed the presence of apatite, CaO, Al 2 O 3 , Fe 2 O 3 and SiO 2 , in which carbonate was detected as the main gangue. Two sets of direct and reverse flotation tests were performed using samples from this deposit with 10% P 2 O 5 . In phosphate flotation (direct approach), the samples were conditioned with sodium silica, oleic acid-fuel oil and Armac T-fuel oil. The direct flotation at pH=9.2 yielded a product with 23.2% of P 2 O 5 and 75.16% recovery. The reverse flotation tests were carried out at pH=5.2, with floating carbonate and pulp de-oiling, using H 2 SO 4 and wash water, and phosphate was then floated from siliceous gangue. In the second sets of the reverse approach, depressing the phosphate and floating silica with Amines in natural pH were done. However the best concentrate assay was 31.2% P 2 O 5 with a 71.12% recovery, which was obtained from reverse tests

Optimization of calcium phosphate fine ceramic powders preparation

Science.gov (United States)

Sezanova, K.; Tepavitcharova, S.; Rabadjieva, D.; Gergulova, R.; Ilieva, R.

2013-12-01

The effect of biomimetic synthesis method, reaction medium and further precursor treatments on the chemical and phase composition, crystal size and morphology of calcium phosphates was examined. Nanosized calcium phosphate precursors were biomimetically precipitated by the method of continuous precipitation in three types of reaction media at pH 8: (i) SBF as an inorganic electrolyte system; (ii) organic (glycerine) modified SBF (volume ratio of 1:1); (iii) polymer (10 g/l xanthan gum or 10 g/l guar gum) modified SBF (volume ratio of 1:1). After maturation (24 h) the samples were lyophilized, calcinated at 300°C for 3 hours, and washed with water, followed by new gelation, lyophilization and step-wise (200, 400, 600, 800, and 1000°C, each for 3 hours) sintering. The reaction medium influenced the chemical composition and particle size but not the morphology of the calcium phosphate powders. In all studied cases bi-phase calcium phosphate fine powders with well-shaped spherical grains, consisting of β-tricalcium phosphate (β-TCP) and hydroxyapatite (HA) with a Ca/P ratio of 1.3 - 1.6 were obtained. The SBF modifiers decreased the particle size of the product in the sequence guar gum ˜ xanthan gum < glycerin < SBF medium.

Uranium Extraction from Phosphates: - Background, Opportunities, Process Overview & Way Forward for Commercialisation

International Nuclear Information System (INIS)

Tulsidas, Harikrishnan; Hilton, Julian; Kumar Haldar, Tapan

2014-01-01

Uranium Extraction from Phosphate - an attractive proposition: • Uranium is co-product of phosphate Industry and makes phosphate Industry economically viable & socially more acceptable; • Enable utilisation of mineral deposits having low Phosphate value through economic co-production of Phosphatic fertiliser & Uranium; • Bring new countries in global map of Uranium resources; • Enables socio-economic up-gradation of major part of global population by achieving Energy, food & Environmental security - so important in today’s scenario

Phosphate, urea and creatinine clearances: haemodialysis adequacy assessed by weekly monitoring.

Science.gov (United States)

Debowska, Malgorzata; Wojcik-Zaluska, Alicja; Ksiazek, Andrzej; Zaluska, Wojciech; Waniewski, Jacek

2015-01-01

The specific distribution of phosphate and the control mechanisms for its plasma level makes phosphate kinetics during haemodialysis (HD) considerably different from those of urea and creatinine and makes the quantitative evaluation of adequacy of phosphate removal difficult. We propose the application of equivalent continuous clearance (ECC) as a phosphate adequacy parameter and compare it with ECC for creatinine and urea. Three consecutive dialysis sessions were evaluated for 25 patients on maintenance HD. Concentrations of phosphate, urea and creatinine in plasma were measured every 1h during the treatment and 45 min after, and every 30 min in dialysate. ECC was calculated using the removed solute mass assessed in dialysate and weekly solute profile in plasma. Similar calculations were performed also for the midweek dialysis session only. Different versions of the reference concentration for ECC were applied. ECC with peak average reference concentration was 5.4 ± 1.0 for phosphate, 7.0 ± 1.0 for urea and 4.7 ± 1.0 mL/min for creatinine. ECC for urea and creatinine were well correlated in contrast to the correlations of ECC for phosphate versus urea and creatinine. Midweek ECC were higher than weekly ECC, but they were well correlated for urea and creatinine, but only weakly for phosphate. HD adequacy monitoring for phosphate may be performed using ECC, but it is less predictable than similar indices for urea and creatinine. The values of ECC for phosphate are within the range expected for its molecular size compared with those for urea and creatinine. © The Author 2014. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.

Synthesis of β-tricalcium phosphate.

Science.gov (United States)

Chaair, H; Labjar, H; Britel, O

2017-09-01

Ceramics play a key role in several biomedical applications. One of them is bone grafting, which is used for treating bone defects caused by injuries or osteoporosis. Calcium-phosphate based ceramic are preferred as bone graft biomaterials in hard tissue surgery because their chemical composition is close to the composition of human bone. They also have a marked bioresorbability and bioactivity. In this work, we have developed methods for synthesis of β-tricalcium phosphate apatite (β-TCP). These products were characterized by different techniques such as X-ray diffraction, infrared spectroscopy, scanning electron microscopy and chemical analysis. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Development of zirconium/magnesium phosphate composites for immobilization of fission products

International Nuclear Information System (INIS)

Singh, D.; Tlustochowicz, M.; Wagh, A.S.

1999-01-01

Novel chemically bonded phosphate ceramics have been investigated for the capture and stabilization of volatile fission-product radionuclides. The authors have used low-temperature processing to fabricate zirconium phosphate and zirconium/magnesium phosphate composites. A zirconium/magnesium phosphate composite has been developed and shown to stabilize ash waste that has been contaminated with a radioactive surrogate of the 137 Cs and 90 Sr species. Excellent retention of cesium in the phosphate matrix system was observed in both short- and long-term leaching tests. The retention factor determined by the USEPA Toxicity Characteristic Leaching Procedure was one order of magnitude better for cesium that for strontium. The effective diffusivity, at room temperature, for cesium and strontium in the waste forms was estimated to be as low as 2.4 x 10 -13 and 1.2 x 10 -11 m 2 /s, respectively. This behavior was attributed to the capture of cesium in the layered zirconium phosphate structure via an intercalation ion-exchange reaction, followed by microencapsulation. However, strontium is believed to be precipitated out in its phosphate form and subsequently microencapsulated in the phosphate ceramic. The performance of these final waste forms, as indicated by the compression strength and the durability in aqueous environments, satisfies the regulatory criteria

Distinct generation, pharmacology, and distribution of sphingosine 1-phosphate and dihydro-sphingosine 1-phosphate in human neural progenitor cells

Science.gov (United States)

In-vivo and in-vitro studies suggest a crucial role for Sphingosine 1-phosphate (S1P) and its receptors in the development of the nervous system. Dihydrosphingosine 1-phosphate (dhS1P), a reduced form of S1P, is an active ligand at S1P receptors, but the pharmacology and physiology of dhS1P has not...

Stimulation of Suicidal Erythrocyte Death by Increased Extracellular Phosphate Concentrations

Directory of Open Access Journals (Sweden)

Jakob Voelkl

2014-02-01

Full Text Available Background/Aim: Anemia in renal insufficiency results in part from impaired erythrocyte formation due to erythropoietin and iron deficiency. Beyond that, renal insufficiency enhances eryptosis, the suicidal erythrocyte death characterized by phosphatidylserine-exposure at the erythrocyte surface. Eryptosis may be stimulated by increase of cytosolic Ca2+-activity ([Ca2+]i. Several uremic toxins have previously been shown to stimulate eryptosis. Renal insufficiency is further paralleled by increase of plasma phosphate concentration. The present study thus explored the effect of phosphate on erythrocyte death. Methods: Cell volume was estimated from forward scatter, phosphatidylserine-exposure from annexin V binding, and [Ca2+]i from Fluo3-fluorescence. Results: Following a 48 hours incubation, the percentage of phosphatidylserine exposing erythrocytes markedly increased as a function of extracellular phosphate concentration (from 0-5 mM. The exposure to 2 mM or 5 mM phosphate was followed by slight but significant hemolysis. [Ca2+]i did not change significantly up to 2 mM phosphate but significantly decreased at 5 mM phosphate. The effect of 2 mM phosphate on phosphatidylserine exposure was significantly augmented by increase of extracellular Ca2+ to 1.7 mM, and significantly blunted by nominal absence of extracellular Ca2+, by additional presence of pyrophosphate as well as by presence of p38 inhibitor SB203580. Conclusion: Increasing phosphate concentration stimulates erythrocyte membrane scrambling, an effect depending on extracellular but not intracellular Ca2+ concentration. It is hypothesized that suicidal erythrocyte death is triggered by complexed CaHPO4.

Nuclear waste immobilization in iron phosphate glasses

International Nuclear Information System (INIS)

Garcia, D.A.; Rodriguez, Diego A.; Menghini, Jorge E.; Bevilacqua, Arturo

2007-01-01

Iron-phosphate glasses have become important in the nuclear waste immobilization area because they have some advantages over silicate-based glasses, such as a lower processing temperature and a higher nuclear waste load without losing chemical and mechanical properties. Structure and chemical properties of iron-phosphate glasses are determined in terms of the main components, in this case, phosphate oxide along with the other oxides that are added to improve some of the characteristics of the glasses. For example, Iron oxide improves chemical durability, lead oxide lowers fusion temperature and sodium oxide reduces viscosity at high temperature. In this work a study based on the composition-property relations was made. We used different techniques to characterize a series of iron-lead-phosphate glasses with uranium and aluminium oxide as simulated nuclear waste. We used the Arquimedes method to determine the bulk density, differential temperature analysis (DTA) to determine both glass transition temperature and crystallization temperature, dilatometric analysis to calculate the linear thermal expansion coefficient, chemical durability (MCC-1 test) and X-ray diffraction (XRD). We also applied some theoretic models to calculate activation energies associated with the glass transition temperature and crystallization processes. (author)

Molecular appraisal of intestinal parasitic infection in transplant recipients

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Pooja Yadav

2016-01-01

Full Text Available Background & objectives: Diarrhoea is the main clinical manifestation caused by intestinal parasitic infections in patients, with special reference to transplant recipients who require careful consideration to reduce morbidity and mortality. Further, molecular characterization of some important parasites is necessary to delineate the different modes of transmission to consider appropriate management strategies. We undertook this study to investigate the intestinal parasitic infections in transplant recipients with or without diarrhoea, and the genotypes of the isolated parasites were also determined. Methods: Stool samples from 38 transplant recipients comprising 29 post-renal, two liver and seven bone marrow transplant (BMT recipients presenting with diarrhoea and 50 transplant recipients (42 post-renal transplant, eight BMT without diarrhoea were examined for the presence of intestinal parasites by light microscopy using wet mount, modified Ziehl-Neelsen staining for intestinal coccidia and modified trichrome staining for microsporidia. Genotypes of Cryptosporidium species were determined by multilocus genotyping using small subunit ribosomal (SSUrRNA, Cryptosporidium oocyst wall protein (COWP and dihydrofolate reductase (DHFR as the target genes. Assemblage study for Giardia lamblia was performed using triose phosphate isomerase (TPI as the target gene. Samples were also screened for bacterial, fungal and viral pathogens. Results: The parasites that were detected included Cryptosporidium species (21%, 8/38, Cystoisospora (Isospora belli (8%, 3, Cyclospora cayetanensis (5%, 2, G. lamblia (11%, 4, Hymenolepis nana (11%, 4, Strongyloides stercoralis (3%, 1 and Blastocystis hominis (3%, 1. Multilocus genotyping of Cryptosporidium species at SSUrRNA, COWP and DHFR loci could detect four isolates of C. hominis; two of C. parvum, one of mixed genotype and one could not be genotyped. All the C. hominis isolates were detected in adult post

The antimicrobial activity of as-prepared silver-loaded phosphate glasses and zirconium phosphate

International Nuclear Information System (INIS)

Jing, Wang; Jiang, Ji Zhi; Yang, Yang; Yan, Zhao Chun; Yan, Wang Xiao; He, Shui Zhong

2016-01-01

The antimicrobial activities of silver-loaded zirconium phosphate (JDG) and silver-loaded phosphate glasses (ZZB) against Escherichia coli were studied. Although the silver content in JDG was higher than that in ZZB, ZZB suspensions showed better antimicrobial property than JDG suspensions, especially at low concentrations. The antimicrobial activity was analyzed using minimum inhibitory concentrations, bacterial inhibition ring tests, and detection of silver ions in the suspensions. Furthermore, the amounts of silver ions in suspensions with/without bacterial cells were analyzed. Results revealed that only a portion of released silver ions could be adsorbed by E. coli cells, which are critical to cell death. The damaged microstructures of E. coli cells observed by transmission electron microscopy may further prove that the adsorbed silver ions play an important role in the antimicrobial process.

Interaction between calcium and phosphate adsorption on goethite

NARCIS (Netherlands)

Rietra, R.P.J.J.; Hiemstra, T.; Riemsdijk, van W.H.

2001-01-01

Quantitatively, little is known about the ion interaction processes that are responsible for the binding of phosphate in soil, water, and sediment, which determine the bioavailability and mobility of phosphate. Studies have shown that metal hydroxides are often responsible for the binding of PO4 in

Consortium inoculum of five thermo-tolerant phosphate solubilizing Actinomycetes for multipurpose biofertilizer preparation.

Science.gov (United States)

Nandimath, Arusha P; Karad, Dilip D; Gupta, Shantikumar G; Kharat, Arun S

2017-10-01

Alkaline pH of the soil facilitates the conversion of phosphate present in phosphate fertilizer applied in the field to insoluble phosphate which is not available to plants. Problem of soluble phosphate deficiency arises, primarily due to needless use of phosphate fertilizer. We sought to biofertilizer with the thermo-tolerant phosphate solubilizing actinomycetes consortium that could convert insoluble phosphate to soluble phosphate at wider temperature range. In the present investigation consortium of five thermo-tolerant phosphate solubilizing actinomycetes was applied for preparation of inoculum to produce multipurpose bio-fertilizer. Phosphates solubilizing thermo-tolerant 32 actinomycetes strains were processed for identification with the use of PIBWIN software and were screened for phosphate solubilizing activity. Amongst these five actinomycetes were selected on the basis of their ability to produce cellulase, chitinase, pectinase, protease, lipase, amylase and phosphate solubilizing enzymes. Ability to produce these enzymes at 28°C and 50°C were examined. Biofertilizer was prepared by using agricultural waste as a raw material. While preparation of bio-fertilizer the pH decreased from 7.5 to 4.3 and temperature increased up to 74°C maximum at the end of 4 th week and in subsequent week it started to decline gradually till it reached around 50°C, which was found to be stable up to eighth week. This thermo-tolerant actinomycetes consortium released soluble phosphate of up to 46.7 μg ml -1 . As the mesophilic organisms die out at high temperature of composting hence thormo-tolerant actinomycetes would be the better substitute for preparation of phosphate solubilizing bio-fertilizer with added potential to degrade complex macromolecules in composting.

Origin of Life and the Phosphate Transfer Catalyst

Science.gov (United States)

Piast, Radosław W.; Wieczorek, Rafał M.

2017-03-01

In this paper, we revisit several issues relevant to origin-of-life research and propose a Phosphate Transfer Catalyst hypothesis that furthers our understanding of some of the key events in prebiotic chemical evolution. In the Phosphate Transfer Catalyst hypothesis, we assume the existence of hypothetical metallopeptides with phosphate transfer activity that use abundant polyphosphates as both substrates and energy sources. Nonspecific catalysis by this phosphate transfer catalyst would provide a variety of different products such as phosphoryl amino acids, nucleosides, polyphosphate nucleotides, nucleic acids, and aminoacylated nucleic acids. Moreover, being an autocatalytic set and metabolic driver at the same time, it could possibly replicate itself and produce a collective system of two polymerases; a nucleic acid able to catalyze peptide bond formation and a peptide able to polymerize nucleic acids. The genetic code starts at first as a system that reduces the energy barrier by bringing substrates (2'/3' aminoacyl-nucleotides) together, an ancestral form of the catalysis performed by modern ribosomes.

Inorganic phosphate inhibits sympathetic neurotransmission in canine saphenous veins

International Nuclear Information System (INIS)

Edoute, Y.; Vanhoutte, P.M.; Shepherd, J.T.

1987-01-01

Inorganic phosphate has been proposed as the initiator of metabolic vasodilatation in active skeletal muscle. The present study was primarily designed to determine if this substance has an inhibitory effect on adrenergic neurotransmission. Rings of canine saphenous veins were suspended for isometric tension recording in organ chambers. A comparison was made of the ability of inorganic phosphate (3 to 14 mM) to relax rings contracted to the same degree by electrical stimulation, exogenous norepinephrine, and prostaglandin F/sub 2α/. The relaxation during electrical stimulation was significantly greater at all concentrations of phosphate. In strips of saphenous veins previously incubated with [ 3 H]norepinephrine, the depression of the contractile response caused by phosphate during electrical stimulated was accompanied by a significant reduction in the overflow of labeled neurotransmitter. Thus inorganic phosphate inhibits sympathetic neurotransmission and hence may have a key role in the sympatholysis in the active skeletal muscles during exercise. By contrast, in this preparation, it has a modest direct relaxing action on the vascular smooth muscle

Uranium traps in the phosphate bearing sudr chalk, in northeastern sinai, Egypt

International Nuclear Information System (INIS)

Hussein, H.A.; El-Aassy, I.E.; Mahdy, M.A.; Dabbour, G.A.; Mansour, M.Gh.; Morsy, A.M.

1998-01-01

The maastrichtian sudr formation in northeastern sinai is composed of three members, the lower chalk, the middle phosphate and chart-bearing and the upper chalk members. Lemon yellow secondary uranium mineralization, distributed in the lower chalk member and in some phosphate beds from the middle phosphate member are observed. The XRD analyses of some samples from the uranium bearing chalk and the phosphate beds showed the presence of the secondary uranium minerals carnotite, bergenite and upalite. The mode of uranium occurrences could be interpreted as a result of the phosphatic beds decomposition and their subjection to later diagenetic processes. Uranium leaching circulation from phosphate rocks led to the liberation of uranium from the phosphates, and vanadium from the bituminous material and clay minerals. These migrated and were deposited locally and within the underlying chalk beds which acted as a lithologic trap

Recovery of uranium and the lanthanides from phosphate rock

Energy Technology Data Exchange (ETDEWEB)

Habashi, F; Awadalla, F T; Zailaf, M

1986-06-01

A process is proposed for the treatment of phosphate rock for the recovery of uranium and lanthanides. The process assures the production of phosphatic fertilisers without polluting the environment with radioactive material.

Radiation exposure due to agricultural uses of phosphate fertilizers

International Nuclear Information System (INIS)

Khater, Ashraf E.M.; AL-Sewaidan, H.A.

2008-01-01

Radiological impacts of phosphate rocks mining and manufacture could be significant due to the elevated radioactivity contents of the naturally occurring radioactive materials (NORM), such as 238 U series, 232 Th series and 40 K, in some phosphate deposits. Over the last decades, the land reclamation and agriculture activities in Saudi Arabia and other countries have been widely expanded. Therefore, the usage of chemical fertilizers is increased. Selected phosphate fertilizers samples were collected and the specific activities of NORM were measured using a gamma ray spectrometer based on a hyper pure germanium detector and alpha spectrometer based on surface barrier detector. The obtained results show remarkable wide variations in the radioactivity contents of the different phosphate fertilizer samples. The mean (ranges) of specific activities for 226 Ra, 210 Po, 232 Th and 40 K, and radium equivalent activity are 75 (3-283), 25 (0.5-110), 23 (2-74), 2818 (9-6501) Bq/kg and 283 (7-589) Bq/kg, respectively. Based on dose calculations, the increment of the public radiation exposure due to the regular agricultural usage of phosphate fertilizers is negligible. Its average value 1 m above the ground is about 0.12 nGy/h where the world average value due to the NORM in soil is 51 nGy/h. Direct radiation exposures of the farmers due to phosphate fertilizers application was not considered in our study

Uptake of 15N-labelled urea and 32P-labelled phosphate from acid-based urea phosphate and granular fertilizers

International Nuclear Information System (INIS)

Bole, J.B.

1986-01-01

The availability of nitrogen and phosphorus in fertilizer products labelled with both 32 P and 15 N was measured in a growth chamber experiment. The uptake of N and P by soft white spring wheat (Triticum aestivum L.) from a solution of acid urea phosphate fertilizer did not differ significantly from that of a mixture of granular urea and monammonium phosphate fertilizer. The fertilizer-P uptake efficiency of both sources was higher in a neutral soil than in acid or calcareous soils. Banding either fertilizer increased the uptake of fertilizer P compared with sources mixed with the soil, but did not significantly affect fertilizer-N uptake. The increase in fertilizer-P efficiency due to banding was significantly greater for the urea-monammonium phosphate than for the acid urea phosphate solution. Banding fertilizer did not increase the uptake of fertilizer P in the calcareous soil, and decreased the uptake of fertilizer N in that soil compared with mixed treatments. It is suggested that soluble Ca formed from the reaction of acid with naturally occurring lime may have reduced the availability of fertilizer P in the band

The disulfide isomerase ERp57 is required for fibrin deposition in vivo.

Science.gov (United States)

Zhou, J; Wu, Y; Wang, L; Rauova, L; Hayes, V M; Poncz, M; Essex, D W

2014-11-01

ERp57 is required for platelet function; however, whether ERp57 contributes to fibrin generation is unknown. Using an inhibitory anti-ERp57 antibody (mAb1), Pf4-Cre/ERp57(fl/fl) mice, Tie2-Cre/ERp57(fl/fl) mice, and mutants of ERp57, we analyzed the function of ERp57 in laser-induced thrombosis. Fibrin deposition was decreased in Pf4-Cre/ERp57(fl/fl) mice, consistent with a role for platelet ERp57 in fibrin generation. Fibrin deposition was further decreased with infusion of mAb1 and in Tie2-Cre/ERp57(fl/fl) mice, consistent with endothelial cells also contributing to fibrin deposition. Infusion of eptibifatide inhibited platelet and fibrin deposition, confirming a role for platelets in fibrin deposition. Infusion of recombinant ERp57 corrected the defect in fibrin deposition but not platelet accumulation, suggesting a direct effect of ERp57 on coagulation. mAb1 inhibited thrombin generation in vitro, consistent with a requirement for ERp57 in coagulation. Platelet accumulation was decreased to similar extents in Pf4-Cre/ERp57(fl/fl) mice, Tie2-Cre/ERp57(fl/fl) mice and normal mice infused with mAb1. Infusion of completely inactivated ERp57 or ERp57 with a non-functional second active site inhibited fibrin deposition and platelet accumulation, indicating that the isomerase activity of the second active site is required for these processes. ERp57 regulates thrombosis via multiple targets. © 2014 International Society on Thrombosis and Haemostasis.

Phosphate adsorption using modified iron oxide-based sorbents

Science.gov (United States)

Phosphate RemovalThis dataset is associated with the following publication:Lalley , J., C. Han , G. RamMohan , T. Speth , J. Garland , M. Nadagouda , and D. Dionysiou. Phosphate Removal using Modified Bayoxide®E33 Adsorption Media. WATER RESEARCH. Elsevier Science Ltd, New York, NY, USA, issue}: 96-107, (2015).

Characterization of iron phosphate glasses prepared by microwave heating

International Nuclear Information System (INIS)

Almeida, Fabio Jesus Moreira de

2006-01-01

Phosphate glasses have been investigated since the fifties, because they are relatively easy to prepare, have low melting temperatures (1000 deg C - 1200 deg C and low glass transition. However, these glasses were very sensitive to humidity, showing a very low chemical durability. Iron phosphate glasses have been prepared by melting inorganic precursors in conventional electric furnaces and induction furnaces. By adding iron, phosphate glasses became chemical resistant and were thought to be used as nuclear waste forms or mechanical resistance fibers. The use of microwaves has been investigated because it makes possible a fast and homogeneous heating of the materials. Microwave promotes the self-heating of the material by the interaction of the external electromagnetic field with the molecules and ions of the material. Niobium phosphate glasses was also produced already through the heating of precursors in microwave ovens. Other glasses containing iron in theirs structure was produced by conventional furnaces and they had your structures analyzed. But even so, it was not still published synthesis of iron phosphate glasses starting from the melting of precursors materials in microwave ovens. In the present work mixtures of (NH 4 ) 2 HPO 4 and Fe 3 O 4 or (NH 4 ) 2 HPO 4 and Fe 2 O 3 were exposed to microwave energy with electromagnetic waves of 2,45 GHz. It was proposed that the absorption of this radiation for the material causes the heating from room temperature to melting temperature. The obtained iron phosphate glasses was analyzed by X-ray diffraction, Moessbauer spectroscopy, and Differential Thermal Analysis. Iron phosphate glasses were also produced in electrical furnaces for comparison. (author)

Characterization of iron phosphate glasses prepared by microwave heating

International Nuclear Information System (INIS)

Almeida, Fabio Jesus Moreira de

2006-01-01

Phosphate glasses have been investigated since the fifties, because they are relatively easy to prepare, have low melting temperatures (1000 deg C - 1200 deg C), and low glass transition. However, these glasses were very sensitive to humidity, showing a very low chemical durability. Iron phosphate glasses have been prepared by melting inorganic precursors in conventional electric furnaces and induction furnaces. By adding iron, phosphate glasses became chemical resistant and were thought to be used as nuclear waste forms or mechanical resistance fibers. The use of microwaves has been investigated because it makes possible a fast and homogeneous heating of the materials. Microwave promotes the self-heating of the material by the interaction of the external electromagnetic field with the molecules and ions of the material. Niobium phosphate glasses was also produced already through the heating of precursors in microwave ovens. Other glasses containing iron in theirs structure was produced by conventional furnaces and they had your structures analyzed. But even so, it was not still published synthesis of iron phosphate glasses starting from the melting of precursors materials in microwave ovens. In the present work mixtures of (NH 4 ) 2 HPO 4 and Fe 3 O 4 or (NH 4 ) 2 HPO 4 and Fe 2 O 3 were exposed to microwave energy with electromagnetic waves of 2,45 GHz. It was proposed that the absorption of this radiation for the material causes the heating from room temperature to melting temperature. The obtained iron phosphate glasses was analyzed by X-ray diffraction, Moessbauer spectroscopy, and Differential Thermal Analysis. Iron phosphate glasses were also produced in electrical furnaces for comparison. (author)

Iron phosphate glasses: Bulk properties and atomic scale structure

Energy Technology Data Exchange (ETDEWEB)

Joseph, Kitheri; Stennett, Martin C.; Hyatt, Neil C.; Asuvathraman, R.; Dube, Charu L.; Gandy, Amy S.; Govindan Kutty, K. V.; Jolley, Kenny; Vasudeva Rao, P. R.; Smith, Roger

2017-10-01

Bulk properties such as glass transition temperature, density and thermal expansion of iron phosphate glass compositions, with replacement of Cs by Ba, are investigated as a surrogate for the transmutation of 137Cs to 137Ba, relevant to the immobilisation of Cs in glass. These studies are required to establish the appropriate incorporation rate of 137Cs in iron phosphate glass. Density and glass transition temperature increases with the addition of BaO indicating the shrinkage and reticulation of the iron phosphate glass network. The average thermal expansion coefficient reduces from 19.8 × 10-6 K-1 to 13.4 × 10-6 K-1, when 25 wt. % of Cs2O was replaced by 25 wt. % of BaO in caesium loaded iron phosphate glass. In addition to the above bulk properties, the role of Ba as a network modifier in the structure of iron phosphate glass is examined using various spectroscopic techniques. The FeII content and average coordination number of iron in the glass network was estimated using Mössbauer spectroscopy. The FeII content in the un-doped iron phosphate glass and barium doped iron phosphate glasses was 20, 21 and 22 ± 1% respectively and the average Fe coordination varied from 5.3 ± 0.2 to 5.7 ± 0.2 with increasing Ba content. The atomic scale structure was further probed by Fe K-edge X-ray absorption spectroscopy. The average coordination number provided by extended X-ray absorption fine structure spectroscopy and X-ray absorption near edge structure was in good agreement with that given by the Mössbauer data.