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Sample records for rhizobium etli pyruvate

  1. Interaction Between the Biotin Carboxyl Carrier Domain and the Biotin Carboxylase Domain in Pyruvate Carboxylase from Rhizobium etli†

    Science.gov (United States)

    Lietzan, Adam D.; Menefee, Ann L.; Zeczycki, Tonya N.; Kumar, Sudhanshu; Attwood, Paul V.; Wallace, John C.; Cleland, W. Wallace; Maurice, Martin St.

    2011-01-01

    Pyruvate carboxylase (PC) catalyzes the ATP-dependent carboxylation of pyruvate to oxaloacetate, an important anaplerotic reaction in mammalian tissues. To effect catalysis, the tethered biotin of PC must gain access to active sites in both the biotin carboxylase domain and the carboxyl transferase domain. Previous studies have demonstrated that a mutation of threonine 882 to alanine in PC from Rhizobium etli renders the carboxyl transferase domain inactive and favors the positioning of biotin in the biotin carboxylase domain. We report the 2.4 Å resolution X-ray crystal structure of the Rhizobium etli PC T882A mutant which reveals the first high-resolution description of the domain interaction between the biotin carboxyl carrier protein domain and the biotin carboxylase domain. The overall quaternary arrangement of Rhizobium etli PC remains highly asymmetrical and is independent of the presence of allosteric activator. While biotin is observed in the biotin carboxylase domain, its access to the active site is precluded by the interaction between Arg353 and Glu248, revealing a mechanism for regulating carboxybiotin access to the BC domain active site. The binding location for the biotin carboxyl carrier protein domain demonstrates that tethered biotin cannot bind in the biotin carboxylase domain active site in the same orientation as free biotin, helping to explain the difference in catalysis observed between tethered biotin and free biotin substrates in biotin carboxylase enzymes. Electron density located in the biotin carboxylase domain active site is assigned to phosphonoacetate, offering a probable location for the putative carboxyphosphate intermediate formed during biotin carboxylation. The insights gained from the T882A Rhizobium etli PC crystal structure provide a new series of catalytic snapshots in PC and offer a revised perspective on catalysis in the biotin-dependent enzyme family. PMID:21958016

  2. Effet de la co-inoculation du rhizobium et de mycorhizes sur les ...

    African Journals Online (AJOL)

    SARAH

    30 déc. 2013 ... RÉSUMÉ. Objectif : Les sols sahéliens se caractérisent par une faible fertilité dont l'amélioration se fait par la pratique de la jachère ou l'apport du fumier. La fixation de l'azote atmosphérique par certaines légumineuses est peu performante voir inefficace. De nos jours, l'inoculation de rhizobium et de ...

  3. Interaction of an IHF-like protein with the Rhizobium etli nifA promoter.

    Science.gov (United States)

    Benhassine, Traki; Fauvart, Maarten; Vanderleyden, Jos; Michiels, Jan

    2007-06-01

    The nifA gene fulfills an essential role in the regulation of nitrogen fixation genes in Rhizobium etli. Transcription analysis of the nifA gene, assessed using promoter deletions, indicated an oxygen-independent expression, threefold higher during symbiosis as compared with free-living conditions. Electrophoretic mobility shift assays using those nifA promoter deletion fragments, which were actively transcribed, demonstrated the specific interaction with R. etli cellular protein(s) resulting in the formation of two DNA-protein complexes. An interacting protein was purified by liquid chromatography on Heparin Sepharose and Mono S columns. The purified 12 kDa R. etli protein cross-reacted with antibodies directed against Escherichia coli integration host factor (IHF). Furthermore, purified E. coli IHF was able to specifically bind to the R. etli nifA promoter region. These results point to an as yet undisclosed function of IHF in the regulation of R. etli nifA expression.

  4. The extracellular proteome of Rhizobium etli CE3 in exponential and stationary growth phase

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    Mendoza-Hernández Guillermo

    2010-10-01

    Full Text Available Abstract Background The extracellular proteome or secretome of symbiotic bacteria like Rhizobium etli is presumed to be a key element of their infection strategy and survival. Rhizobia infect the roots of leguminous plants and establish a mutually beneficial symbiosis. To find out the possible role of secreted proteins we analyzed the extracellular proteome of R. etli CE3 in the exponential and stationary growth phases in minimal medium, supplemented with succinate-ammonium. Results The extracellular proteins were obtained by phenol extraction and identified by LC-ESI MS/MS. We identified 192 and 191 proteins for the exponential and stationary phases respectively. Using the software Signal P, we predicted signal peptides for 12.95% and 35.60% of the proteins identified in the exponential and stationary phases, respectively, which could therefore be secreted by the Sec pathway. For the exponential growth phase, we found in abundance proteins like the ribosomal proteins, toxins and proteins belonging to the group "defence mechanisms". For the stationary growth phase, we found that the most abundant proteins were those with unknown function, and in many of these we identified characteristic domains of proteases and peptidases. Conclusions Our study provided the first dataset of the secretome of R. etli and its modifications, which may lead to novel insights into the adaptive response of different stages of growth. In addition, we found a high number of proteins with unknown function; these proteins could be analyzed in future research to elucidate their role in the extracellular proteome of R. etli.

  5. Differential regulation of Rhizobium etli rpoN2 gene expression during symbiosis and free-living growth.

    Science.gov (United States)

    Michiels, J; Moris, M; Dombrecht, B; Verreth, C; Vanderleyden, J

    1998-07-01

    The Rhizobium etli rpoN1 gene, encoding the alternative sigma factor sigma54 (RpoN), was recently characterized and shown to be involved in the assimilation of several nitrogen and carbon sources during free-living aerobic growth (J. Michiels, T. Van Soom, I. D'hooghe, B. Dombrecht, T. Benhassine, P. de Wilde, and J. Vanderleyden, J. Bacteriol. 180:1729-1740, 1998). We identified a second rpoN gene copy in R. etli, rpoN2, encoding a 54.0-kDa protein which displays 59% amino acid identity with the R. etli RpoN1 protein. The rpoN2 gene is cotranscribed with a short open reading frame, orf180, which codes for a protein with a size of 20.1 kDa that is homologous to several prokaryotic and eukaryotic proteins of similar size. In contrast to the R. etli rpoN1 mutant strain, inactivation of the rpoN2 gene did not produce any phenotypic defects during free-living growth. However, symbiotic nitrogen fixation was reduced by approximately 90% in the rpoN2 mutant, whereas wild-type levels of nitrogen fixation were observed in the rpoN1 mutant strain. Nitrogen fixation was completely abolished in the rpoN1 rpoN2 double mutant. Expression of rpoN1 was negatively autoregulated during aerobic growth and was reduced during microaerobiosis and symbiosis. In contrast, rpoN2-gusA and orf180-gusA fusions were not expressed aerobically but were strongly induced at low oxygen tensions or in bacteroids. Expression of rpoN2 and orf180 was abolished in R. etli rpoN1 rpoN2 and nifA mutants under all conditions tested. Under free-living microaerobic conditions, transcription of rpoN2 and orf180 required the RpoN1 protein. In symbiosis, expression of rpoN2 and orf180 occurred independently of the rpoN1 gene, suggesting the existence of an alternative symbiosis-specific mechanism of transcription activation.

  6. Lipopolysaccharides of Rhizobium etli strain G12 act in potato roots as an inducing agent of systemic resistance to infection by the cyst nematode Globodera pallida.

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    Reitz, M; Rudolph, K; Schröder, I; Hoffmann-Hergarten, S; Hallmann, J; Sikora, R A

    2000-08-01

    Recent studies have shown that living and heat-killed cells of the rhizobacterium Rhizobium etli strain G12 induce in potato roots systemic resistance to infection by the potato cyst nematode Globodera pallida. To better understand the mechanisms of induced resistance, we focused on identifying the inducing agent. Since heat-stable bacterial surface carbohydrates such as exopolysaccharides (EPS) and lipopolysaccharides (LPS) are essential for recognition in the symbiotic interaction between Rhizobium and legumes, their role in the R. etli-potato interaction was studied. EPS and LPS were extracted from bacterial cultures, applied to potato roots, and tested for activity as an inducer of plant resistance to the plant-parasitic nematode. Whereas EPS did not affect G. pallida infection, LPS reduced nematode infection significantly in concentrations as low as 1 and 0.1 mg ml(-1). Split-root experiments, guaranteeing a spatial separation of inducing agent and challenging pathogen, showed that soil treatments of one half of the root system with LPS resulted in a highly significant (up to 37%) systemic induced reduction of G. pallida infection of potato roots in the other half. The results clearly showed that LPS of R. etli G12 act as the inducing agent of systemic resistance in potato roots.

  7. Biostimulation of soil polluted 10000 ppm of waste motor oil and phytoremediation with Cicer arietinum improved by Bacillus cereus/Rhizobium etli

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    Juárez-Cisneros Gladys

    2016-08-01

    Full Text Available Soil pollution by waste motor oil (WMO is reducing its productivity. An alternative for removing WMO from soil is by biostimulation (BIS applying animal manure and then phytoremediation (PR by legume improving with plant growth promoting bacteria (PGPB to reduce WMO concentration at level below 4400 ppm limit permit for the NOM-138-SEMARNAT/SSA1-2012 (NOM-138. The aims of this re-search were: i to analyze soil biostimulation polluted by 10000 ppm of WMO applying vermicompost, then subsequent soil phytoremediation with Cicer arietinum inoculated by Bacillus cereus and/or Rhizo-bium etli. In soil after applying BS by VC was measured WMO soil concentration and ii for PR was regarded phenology and biomass of C. arietinum and WMO concentration remaining at the end of this step. The results showed that soil biostimulated by VC, WMO was reduced at 1370 ppm, subsequent PR sowing C. arietinum with R. etli, WMR was reduced at 30 ppm concentration both values below to maxi-mum value accepted by NOM-138. Those data indicate that in soil polluted by WMO the best way to biorecovery soil was to integrate strategy BS/PR the last one improved by genus of PGPB.

  8. Biorestauration of soil polluted by waste motor oil by biostimulation with vermicompost and phytoremediation with Sorghum vulgare inoculated by Bacillus cereus and Rhizobium etli

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    Juárez-Cisneros Gladys

    2014-11-01

    Full Text Available Soil pollution by waste motor oil (WMO caused soil´s lost fertility. The aims of this research where a bioremediation of soil polluted by 10000 ppm of WMO for biostimulation with vermicompost (VC at 3 and 6 % (w/w follow by b phytoremediation (PR of the same soil to eliminate remaining WMO with Sorghum vulgare inoculated with Bacillus cereus and/or Rhizobium etli or Promoting Growth Plant Bacteria (PGPB. At the first step of assay WMO concentration was measured before and after bioremediation. At the second step the same soil phytoremediation was applied for remaining WHO sowing S. vulgare inoculated with PGPB, then at flowering stage its biomass and WHO final concentration was determined. Results showed that soil impacted by WMO biostimulated with VC at 3% was eliminated 8630 ppm of WMO. At the second phase in the same soil PR applied for remaining WMO which was reduced until 210 ppm. Soil polluted by remaining WMO applied PR using S. vulgare plus R. etli WMO was decreased at 260 ppm. While S. vulgare´s biomass inoculated with PGPB was higher compared to S. vulgare grown in soil not polluted by WMO according by ANOVA - Tukey (p > 0.05. These results suggested that soil polluted by WMO could be recovering by applying integrated BR and PR better than just using one type.

  9. The Rhizobium etli rpoN locus: DNA sequence analysis and phenotypical characterization of rpoN, ptsN, and ptsA mutants.

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    Michiels, J; Van Soom, T; D'hooghe, I; Dombrecht, B; Benhassine, T; de Wilde, P; Vanderleyden, J

    1998-04-01

    The rpoN region of Rhizobium etli was isolated by using the Bradyrhizobium japonicum rpoN1 gene as a probe. Nucleotide sequence analysis of a 5,600-bp DNA fragment of this region revealed the presence of four complete open reading frames (ORFs), ORF258, rpoN, ORF191, and ptsN, coding for proteins of 258, 520, 191, and 154 amino acids, respectively. The gene product of ORF258 is homologous to members of the ATP-binding cassette-type permeases. ORF191 and ptsN are homologous to conserved ORFs found downstream from rpoN genes in other bacterial species. Unlike in most other microorganisms, rpoN and ORF191 are separated by approximately 1.6 kb. The R. etli rpoN gene was shown to control in free-living conditions the production of melanin, the activation of nifH, and the metabolism of C4-dicarboxylic acids and several nitrogen sources (ammonium, nitrate, alanine, and serine). Expression of the rpoN gene was negatively autoregulated and occurred independently of the nitrogen source. Inactivation of the ptsN gene resulted in a decrease of melanin synthesis and nifH expression. In a search for additional genes controlling the synthesis of melanin, an R. etli mutant carrying a Tn5 insertion in ptsA, a gene homologous to the Escherichia coli gene coding for enzyme I of the phosphoenolpyruvate:sugar phosphotransferase system, was obtained. The R. etli ptsA mutant also displayed reduced expression of nifH. The ptsN and ptsA mutants also displayed increased sensitivity to the toxic effects of malate and succinate. Growth of both mutants was inhibited by these C4-dicarboxylates at 20 mM at pH 7.0, while wild-type cells grow normally under these conditions. The effect of malate occurred independently of the nitrogen source used. Growth inhibition was decreased by lowering the pH of the growth medium. These results suggest that ptsN and ptsA are part of the same regulatory cascade, the inactivation of which renders the cells sensitive to toxic effects of elevated concentrations of

  10. The Micro-RNA172c-APETALA2-1 Node as a Key Regulator of the Common Bean-Rhizobium etli Nitrogen Fixation Symbiosis1[OPEN

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    Nova-Franco, Bárbara; Íñiguez, Luis P.; Valdés-López, Oswaldo; Leija, Alfonso; Fuentes, Sara I.; Ramírez, Mario; Paul, Sujay

    2015-01-01

    Micro-RNAs are recognized as important posttranscriptional regulators in plants. The relevance of micro-RNAs as regulators of the legume-rhizobia nitrogen-fixing symbiosis is emerging. The objective of this work was to functionally characterize the role of micro-RNA172 (miR172) and its conserved target APETALA2 (AP2) transcription factor in the common bean (Phaseolus vulgaris)-Rhizobium etli symbiosis. Our expression analysis revealed that mature miR172c increased upon rhizobial infection and continued increasing during nodule development, reaching its maximum in mature nodules and decaying in senescent nodules. The expression of AP2-1 target showed a negative correlation with miR172c expression. A drastic decrease in miR172c and high AP2-1 mRNA levels were observed in ineffective nodules. Phenotypic analysis of composite bean plants with transgenic roots overexpressing miR172c or a mutated AP2-1 insensitive to miR172c cleavage demonstrated the pivotal regulatory role of the miR172 node in the common bean-rhizobia symbiosis. Increased miR172 resulted in improved root growth, increased rhizobial infection, increased expression of early nodulation and autoregulation of nodulation genes, and improved nodulation and nitrogen fixation. In addition, these plants showed decreased sensitivity to nitrate inhibition of nodulation. Through transcriptome analysis, we identified 114 common bean genes that coexpressed with AP2-1 and proposed these as being targets for transcriptional activation by AP2-1. Several of these genes are related to nodule senescence, and we propose that they have to be silenced, through miR172c-induced AP2-1 cleavage, in active mature nodules. Our work sets the basis for exploring the miR172-mediated improvement of symbiotic nitrogen fixation in common bean, the most important grain legume for human consumption. PMID:25739700

  11. Symbiotic and phenotypic diversity of Rhizobium leguminosarum bv ...

    African Journals Online (AJOL)

    Administrator

    2011-05-23

    May 23, 2011 ... root nodule bacteria known as Rhizobium leguminosarum bv. viciae. ... nodules, as before by streaking on Yeast-extract mannitol agar medium ... Colony morphology was characterized on YEMA according to. (Ahmed et al.

  12. The micro-RNA72c-APETALA2-1 node as a key regulator of the common bean-Rhizobium etli nitrogen fixation symbiosis.

    Science.gov (United States)

    Nova-Franco, Bárbara; Íñiguez, Luis P; Valdés-López, Oswaldo; Alvarado-Affantranger, Xochitl; Leija, Alfonso; Fuentes, Sara I; Ramírez, Mario; Paul, Sujay; Reyes, José L; Girard, Lourdes; Hernández, Georgina

    2015-05-01

    Micro-RNAs are recognized as important posttranscriptional regulators in plants. The relevance of micro-RNAs as regulators of the legume-rhizobia nitrogen-fixing symbiosis is emerging. The objective of this work was to functionally characterize the role of micro-RNA172 (miR172) and its conserved target APETALA2 (AP2) transcription factor in the common bean (Phaseolus vulgaris)-Rhizobium etli symbiosis. Our expression analysis revealed that mature miR172c increased upon rhizobial infection and continued increasing during nodule development, reaching its maximum in mature nodules and decaying in senescent nodules. The expression of AP2-1 target showed a negative correlation with miR172c expression. A drastic decrease in miR172c and high AP2-1 mRNA levels were observed in ineffective nodules. Phenotypic analysis of composite bean plants with transgenic roots overexpressing miR172c or a mutated AP2-1 insensitive to miR172c cleavage demonstrated the pivotal regulatory role of the miR172 node in the common bean-rhizobia symbiosis. Increased miR172 resulted in improved root growth, increased rhizobial infection, increased expression of early nodulation and autoregulation of nodulation genes, and improved nodulation and nitrogen fixation. In addition, these plants showed decreased sensitivity to nitrate inhibition of nodulation. Through transcriptome analysis, we identified 114 common bean genes that coexpressed with AP2-1 and proposed these as being targets for transcriptional activation by AP2-1. Several of these genes are related to nodule senescence, and we propose that they have to be silenced, through miR172c-induced AP2-1 cleavage, in active mature nodules. Our work sets the basis for exploring the miR172-mediated improvement of symbiotic nitrogen fixation in common bean, the most important grain legume for human consumption. © 2015 American Society of Plant Biologists. All Rights Reserved.

  13. Effets de la fertilisation azotée, de l'inoculation par Rhizobium sp. et du régime des pluies sur la production de la biomasse et la teneur en azote du pois chiche

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    Lachaâl M.

    2009-01-01

    Full Text Available Effect of nitrogen fertilization, inoculation with Rhizobium sp. and precipitation on the biomass production and nitrogen content of chickpea. Water availability and soil fertility (especially soil N content are the major factors affecting chickpea yield in Mediterranean regions, characterized by low rainfall, poorly distributed and rapid mineralization of organic matter. In order to study the effect of N-fertilization and inoculation with Rhizobium on chickpea biomass production and N-content, field experiment were carried out at two stations of INRAT in northern Tunisia during two consecutive years, 2000-2001 and 2001-2002. Results showed that N-fertilization significantly increased shoot biomass and N-content while decreasing nodule mass. Inoculation with both the two Rhizobium strains resulted in nodule mass increase but the shoot N-content was not significantly affected. Regardless of the stations and treatments, rainfall decrease between the two years of the experiment significantly reduced shoot and root biomass while improving nodulation, especially at Oued Beja. However, the nodule developed under water deficit conditions was correlated with a very high decrease of the nitrogen fixed. Nevertheless, the mineral nitrogen apply in soil improved the N-content of aerial parts in the two stations, especially in waterless season.

  14. Denitrification by Rhizobium meliloti

    Energy Technology Data Exchange (ETDEWEB)

    Rosen, A

    1996-10-01

    Rhizobium meliloti strains were investigated for their denitrification activity as free-living cells and in nodules on lucerne (Medicago sativa) roots. They were also investigated for presence of nitrous oxide reductase (nos) activity and for genes using a nosZ probe derived from the Pseudomonas stutzeri. To decide whether R. meliloti strains used as inoculants contribute to the total denitrification activity in a lucerne ley, strains with different denitrifying capacities were used in field and laboratory experiments. The nitrate reduction activity of R. meliloti during anaerobic respiration was compared with that of a strain of Pseudomonas aeruginosa. A great diversity in the denitrification activity was found within strains of R. meliloti, and four of thirteen investigated strains showed an obvious denitrification activity. Two denitrifying bacteria were used as references, one strain each of Bradyrhizobium japonicum and P. aeruginosa. All but one of the R. meliloti strains hybridized to the PstI-fragment of the nosZ-gene from P. stutzeri. Two sizes of the hybridizing fragment, 5 and 7 kb, were noticed. Nos activity was only shown in three R. meliloti strains, and these were all characterized by a high denitrification activity. The potential denitrification activity was about 20, 40, and 80 times higher than the actual denitrification activity for lucerne, fallow, and grass, respectively. The potential denitrification activity was almost the same in lucerne and grass planted soils. Compared with the unplanted soil, the presence of lucerne roots in the soil increased the actual denitrification activity, while roots of both plant species, grass and lucerne, increased the potential denitrification activity in the soil. 32 refs, 7 figs, 1 tab

  15. Chemical characterization of the gels produced by the diazotrophic bacteria Rhizobium tropici and Mesorhizobium sp; Caracterizacao quimica dos geis produzidos pelas bacterias diazotroficas Rhizobium tropici e Mesorhizobium sp.

    Energy Technology Data Exchange (ETDEWEB)

    Monteiro, Nilson Kobori [Departamento de Engenharia e Tecnologia de Alimentos, Instituto de Biociencias, Letras e Ciencias Exatas, Universidade Estadual Paulista, Sao Jose do Rio Preto - SP (Brazil); Aranda-Selverio, Gabriel; Exposti, Diego Tadeu Degli; Silva, Maria de Lourdes Corradi da [Departamento de Fisica, Quimica e Biologia, Faculdade de Ciencias e Tecnologia, Universidade Estadual Paulista, Presidente Prudente - SP (Brazil); Lemos, Eliana Gertrudes Macedo; Campanharo, Joao Carlos [Departamento de Tecnologia, Faculdade de Ciencias Agrarias e Veterinaria, Universidade Estadual Paulista, Jaboticabal - SP (Brazil); Silveira, Joana Lea Meira [Departamento de Bioquimica e Biologia Molecular, Universidade Federal do Parana, Curitiba - PR (Brazil)

    2012-07-01

    The exopolysaccharides with characteristics of gel produced by Rhizobium tropici (EPSRT) and Mesorhizobium sp (EPSMR) are acidic heteropolysaccharide composed mainly of glucose and galactose in a molar ratio of 4:1 and 5:1 respectively, with traces of mannose ({approx} 1%). Chemical analysis showed the presence of uronic acid, pyruvate and acetyl-substituents in the structures of both polymers. Experiments of gel permeation chromatography and polyacrylamide gel electrophoresis showed that EPSRT and EPSMR are homogeneous molecules with low grade of polydispersity. The EPS were characterized using spectroscopic techniques of FT-IR, {sup 1}H and {sup 13}C-NMR. (author)

  16. Insights into the carboxyltransferase reaction of pyruvate carboxylase from the structures of bound product and intermediate analogues

    Science.gov (United States)

    Lietzan, Adam D.; St. Maurice, Martin

    2014-01-01

    Pyruvate carboxylase (PC) is a biotin-dependent enzyme that catalyzes the MgATP- and bicarbonate-dependent carboxylation of pyruvate to oxaloacetate, an important anaplerotic reaction in central metabolism. The carboxyltransferase (CT) domain of PC catalyzes the transfer of a carboxyl group from carboxybiotin to the accepting substrate, pyruvate. It has been hypothesized that the reactive enolpyruvate intermediate is stabilized through a bidentate interaction with the metal ion in the CT domain active site. Whereas bidentate ligands are commonly observed in enzymes catalyzing reactions proceeding through an enolpyruvate intermediate, no bidentate interaction has yet been observed in the CT domain of PC. Here, we report three X-ray crystal structures of the Rhizobium etli PC CT domain with the bound inhibitors oxalate, 3-hydroxypyruvate, and 3-bromopyruvate. Oxalate, a stereoelectronic mimic of the enolpyruvate intermediate, does not interact directly with the metal ion. Instead, oxalate is buried in a pocket formed by several positively charged amino acid residues and the metal ion. Furthermore, both 3-hydroxypyruvate and 3-bromopyruvate, analogs of the reaction product oxaloacetate, bind in an identical manner to oxalate suggesting that the substrate maintains its orientation in the active site throughout catalysis. Together, these structures indicate that the substrates, products and intermediates in the PC-catalyzed reaction are not oriented in the active site as previously assumed. The absence of a bidentate interaction with the active site metal appears to be a unique mechanistic feature among the small group of biotin-dependent enzymes that act on α-keto acid substrates. PMID:24157795

  17. Pyruvate kinase blood test

    Science.gov (United States)

    ... medlineplus.gov/ency/article/003357.htm Pyruvate kinase blood test To use the sharing features on this page, ... energy when oxygen levels are low. How the Test is Performed A blood sample is needed. In the laboratory, white blood ...

  18. Chemical characterization of the gels produced by the diazotrophic bacteria Rhizobium tropici and Mesorhizobium sp

    International Nuclear Information System (INIS)

    Monteiro, Nilson Kobori; Aranda-Selverio, Gabriel; Exposti, Diego Tadeu Degli; Silva, Maria de Lourdes Corradi da; Lemos, Eliana Gertrudes Macedo; Campanharo, Joao Carlos; Silveira, Joana Lea Meira

    2012-01-01

    The exopolysaccharides with characteristics of gel produced by Rhizobium tropici (EPSRT) and Mesorhizobium sp (EPSMR) are acidic heteropolysaccharide composed mainly of glucose and galactose in a molar ratio of 4:1 and 5:1 respectively, with traces of mannose (∼ 1%). Chemical analysis showed the presence of uronic acid, pyruvate and acetyl-substituents in the structures of both polymers. Experiments of gel permeation chromatography and polyacrylamide gel electrophoresis showed that EPSRT and EPSMR are homogeneous molecules with low grade of polydispersity. The EPS were characterized using spectroscopic techniques of FT-IR, 1 H and 13 C-NMR. (author)

  19. Rhizobium metallidurans sp. nov., a symbiotic heavy metal resistant bacterium isolated from the Anthyllis vulneraria Zn-hyperaccumulator.

    Science.gov (United States)

    Grison, Claire M; Jackson, Stephen; Merlot, Sylvain; Dobson, Alan; Grison, Claude

    2015-05-01

    A Gram-stain-negative, aerobic, rod-shaped, non-spore-forming bacterium (ChimEc512(T)) was isolated from 56 host seedlings of the hyperaccumulating Anthyllis vulneraria legume, which was on an old zinc mining site at Les Avinières, Saint-Laurent-Le-Minier, Gard, South of France. On the basis of 16S rRNA gene sequence similarities, strain ChimEc512(T) was shown to belong to the genus Rhizobium and to be most closely related to Rhizobium endophyticum CCGE 2052(T) (98.4%), Rhizobium tibeticum CCBAU 85039(T) (98.1%), Rhizobium grahamii CCGE 502(T) (98.0%) and Rhizobium mesoamericanum CCGE 501(T) (98.0%). The phylogenetic relationships of ChimEc512(T) were confirmed by sequencing and analyses of recA and atpD genes. DNA-DNA relatedness values of strain ChimEc512(T) with R. endophyticum CCGE 2052(T), R. tibeticum CCBAU 85039(T), R. mesoamericanum CCGE 52(T), Rhizobium grahamii CCGE 502(T), Rhizobium etli CCBAU 85039(T) and Rhizobium radiobacter KL09-16-8-2(T) were 27, 22, 16, 18, 19 and 11%, respectively. The DNA G+C content of strain ChimEc512(T) was 58.9 mol%. The major cellular fatty acid was C18 : 1ω7c, characteristic of the genus Rhizobium . The polar lipid profile included phosphatidylethanolamine, phosphatidylmonomethylethanolamine, phosphatidylglycerol and phosphatidylcholine and moderate amounts of aminolipids, phospholipid and sulfoquinovosyl diacylglycerol. Although ChimEc512(T) was able to nodulate A. vulneraria, the nodC and nifH genes were not detected by PCR. The rhizobial strain was tolerant to high concentrations of heavy metals: up to 35 mM Zn and up to 0.5 mM Cd and its growth kinetics was not impacted by Zn. The results of DNA-DNA hybridizations and physiological tests allowed genotypic and phenotypic differentiation of strain ChimEc512(T) from species of the genus Rhizobium with validly published names. Strain ChimEc512(T), therefore, represents a novel species, for which the name Rhizobium metallidurans sp. nov. is proposed, with the type strain

  20. Response of Arbuscular mycorrhizal fungi and Rhizobium ...

    African Journals Online (AJOL)

    The aim of the present study was to investigate the effect ofRhizobium and Arbuscular mycorrhizal fungi inoculation, both individually and in combination on growth and chlorophyll content of economically important plant Vigna unguiculata L. A significant (p < 0.05) increase over control in root length (45.6 cm), shoot height ...

  1. Response of Phaseolus vulgaris cv. Mantequilla to inoculation of Rhizobium native strains of the Ecuador in greenhouse native races of the Ecuador

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    Klever Iván Granda Mora

    2016-10-01

    Full Text Available The development of biofertilizers based on Rhizobium strains for common bean (Phaseolus vulgaris L. requires studies about bacterial interaction with target cultivars. For these reason, the aim of this paper was to determine the effect of the inoculation of Rhizobium native strains, isolated from southern Ecuador, on P. vulgaris cultivar Mantequilla. An assay was performed in greenhouse. It were evaluated the parameters of nodulation, biomass, nitrogen fixation and efficiency of the symbiosis. All inoculated strains were able to nodulate bean seedlings. The total number of nodules, nodular biomass and plant biomass, were favourably affected by inoculation of Rhizobium strains. The best results were obtained with R. mesoamericanum NAM1, R. leguminosarum COL 6 and R. etli PIN 1 strains. The experimental evidences shows the potential of native strains of Rhizobium for it use as biofertilizers because they are able to raise the rates of nitrogen fixation in common bean in southern Ecuador.

  2. Biofertilisasi bakteri rhizobium pada tanaman kedelai (Glycine max (L MERR.

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    Tini Surtiningsih

    2012-02-01

    Full Text Available The aim of this research want to know the influence of the addition Rhizobium bacteria species, dose and combination both ofthem, on growth and production of soybean plant (Glycine max (L Merr.. The experimental design of this research was factorial design4×2, 4 species of Rhizobium are R1 = Rhizobium japonicum, R2 = R. phaseoli, R3 = R. leguminosarum, R4 = mixture of R1, R2 andR3, and 2 dose of inoculan Rhizobium (D1 = 5 m/plant, and D2 = 10 ml/plant with 1010 sel bacteria/ml and 5 replications. Independentvariable is species of Rhizobium, dose of inoculan Rhizobium and combination both of them. Dependent variable is dry matter, weightof nodules and dry weight of seeds. The harvest data was analyzed by Kruskal-Wallis Test using 5% level (a = 0.05 followed by Mann-Whitney Test. The result of this research show that species of Rhizobium, dose of inoculan Rhizobium and combination both of thempresent insignificant result (a > 0.05 on soybean growth and production, but the mixture of Rhizobium species with high level doseof bacteria, present better result than single species with low dose of bacteria.

  3. Phylogenetic relationships and host range of Rhizobium spp. that nodulate Phaseolus vulgaris L.

    Science.gov (United States)

    Hernandez-Lucas, I; Segovia, L; Martinez-Romero, E; Pueppke, S G

    1995-07-01

    We determined the nucleotide sequences of 16S rRNA gene segments from five Rhizobium strains that have been isolated from tropical legume species. All share the capacity to nodulate Phaseolus vulgaris L., the common bean. Phylogenetic analysis confirmed that these strains are of two different chromosomal lineages. We defined the host ranges of two strains of Rhizobium etli and three strains of R. tropici, comparing them with those of the two most divergently related new strains. Twenty-two of the 43 tested legume species were nodulated by three or more of these strains. All seven strains have broad host ranges that include woody species such as Albizia lebbeck, Gliricidia maculata, and Leucaena leucocephala.

  4. Isolated tumoral pyruvate dehydrogenase can synthesize acetoin which inhibits pyruvate oxidation as well as other aldehydes.

    Science.gov (United States)

    Baggetto, L G; Lehninger, A L

    1987-05-29

    Oxidation of 1 mM pyruvate by Ehrlich and AS30-D tumor mitochondria is inhibited by acetoin, an unusual and important metabolite of pyruvate utilization by cancer cells, by acetaldehyde, methylglyoxal and excess pyruvate. The respiratory inhibition is reversed by other substrates added to pyruvate and also by 0.5 mM ATP. Kinetic properties of pyruvate dehydrogenase complex isolated from these tumor mitochondria have been studied. This complex appears to be able to synthesize acetoin from acetaldehyde plus pyruvate and is competitively inhibited by acetoin. The role of a new regulatory pattern for tumoral pyruvate dehydrogenase is presented.

  5. Draft Genome Sequence of Rhizobium sp. Strain TBD182, an Antagonist of the Plant-Pathogenic Fungus Fusarium oxysporum, Isolated from a Novel Hydroponics System Using Organic Fertilizer.

    Science.gov (United States)

    Iida, Yuichiro; Fujiwara, Kazuki; Someya, Nobutaka; Shinohara, Makoto

    2017-03-16

    Rhizobium sp. strain TBD182, isolated from a novel hydroponics system, is an antagonistic bacterium that inhibits the mycelial growth of Fusarium oxysporum but does not eliminate the pathogen. We report the draft genome sequence of TBD182, which may contribute to elucidation of the molecular mechanisms of its fungistatic activity. Copyright © 2017 Iida et al.

  6. Characterization of Rhizobium strain isolated from the roots of ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-10-20

    Oct 20, 2008 ... The Rhizobium species isolated from fenugreek roots have the potential to produce industrially important ... growth of leguminous crops (Dilworth and Parker, 1969). ..... events, such as chemotaxis and root hair colonization,.

  7. Genetic and phenotypic diversity of Rhizobium isolates from Southern Ecuador

    Directory of Open Access Journals (Sweden)

    Roldán Torres-Gutiérrez

    Full Text Available ABSTRACT Rhizobium-legume symbioses play relevant roles in agriculture but have not been well studied in Ecuador. The aim of this study was to characterize the genetic and phenotypic diversity of Rhizobium isolates associated with Phaseolus vulgaris from southern Ecuador. Morpho-cultural characterization, biochemical tests and physiological analyses were conducted to authenticate and determine the diversity of bacteria Rhizobium-like isolates. The genetic diversity of the isolates was determined by molecular techniques, which consisted of bacteria DNA extraction and amplification and sequencing of the 16S rRNA gene. The nodulation parameters and nitrogen fixation for P. vulgaris under greenhouse conditions were also assessed to determine the phenotypic diversity among isolates. Furthermore, bacteria indole-acetic-acid production was evaluated by the colorimetric method. Morpho-cultural and biochemical characteristic assessments demonstrated that Rhizobium-like bacteria was associated with the P. vulgaris nodules. The diversity among the isolates, as determined by physiological analyses, revealed the potential of several isolates to grow at different pH values, salinity conditions and temperatures. Partial sequencing of the 16S rRNA gene identified the Rhizobium genus in every sampling site. From a total of 20 aligned sequences, nine species of Rhizobium were identified. Nodule formation and biomass, as well as nitrogen fixation, showed an increase in plant phenotypic parameters, which could be influenced by IAA production, especially for the strains R. mesoamericanum NAM1 and R. leguminosarum bv. viciae COL6. These results demonstrated the efficiency of native symbiotic diazotrophic strains inoculants for legume production. This work can serve as the basis for additional studies of native Rhizobium strains and to help spread the use of biofertilizers in Ecuadorian fields.

  8. Analysis of synonymous codon usage patterns in the genus Rhizobium.

    Science.gov (United States)

    Wang, Xinxin; Wu, Liang; Zhou, Ping; Zhu, Shengfeng; An, Wei; Chen, Yu; Zhao, Lin

    2013-11-01

    The codon usage patterns of rhizobia have received increasing attention. However, little information is available regarding the conserved features of the codon usage patterns in a typical rhizobial genus. The codon usage patterns of six completely sequenced strains belonging to the genus Rhizobium were analysed as model rhizobia in the present study. The relative neutrality plot showed that selection pressure played a role in codon usage in the genus Rhizobium. Spearman's rank correlation analysis combined with correspondence analysis (COA) showed that the codon adaptation index and the effective number of codons (ENC) had strong correlation with the first axis of the COA, which indicated the important role of gene expression level and the ENC in the codon usage patterns in this genus. The relative synonymous codon usage of Cys codons had the strongest correlation with the second axis of the COA. Accordingly, the usage of Cys codons was another important factor that shaped the codon usage patterns in Rhizobium genomes and was a conserved feature of the genus. Moreover, the comparison of codon usage between highly and lowly expressed genes showed that 20 unique preferred codons were shared among Rhizobium genomes, revealing another conserved feature of the genus. This is the first report of the codon usage patterns in the genus Rhizobium.

  9. Pyruvate reduces 4-aminophenol in vitro toxicity

    International Nuclear Information System (INIS)

    Harmon, R. Christopher; Kiningham, Kinsley K.; Valentovic, Monica A.

    2006-01-01

    Pyruvate has been observed to reduce the nephrotoxicity of some agents by maintaining glutathione status and preventing lipid peroxidation. This study examined the mechanism for pyruvate protection of p-aminophenol (PAP) nephrotoxicity. Renal cortical slices from male Fischer 344 rats were incubated for 30-120 min with 0, 0.1, 0.25 or 0.5 mM PAP in oxygenated Krebs buffer containing 0 or 10 mM pyruvate or glucose (1.28 or 5.5 mM). LDH leakage was increased above control by 0.25 and 0.5 mM PAP beginning at 60 min and by 0.1 mM PAP at 120 min. Pyruvate prevented an increase in LDH leakage at 60- and 120-min exposure to 0.1 and 0.25 mM PAP. Pyruvate also prevented a decline in ATP levels. Glucose (1.28 and 5.5 mM) provided less protection than pyruvate from PAP toxicity. Total glutathione levels were diminished by 0.1 and 0.25 mM PAP within 60 and 30 min, respectively. Pyruvate prevented the decline in glutathione by 0.1 mM PAP at both time periods and at 30 min for 0.25 mM PAP. Pyruvate reduced the magnitude of glutathione depletion by 0.25 mM PAP following a 60-min incubation. Glutathione disulfide (GSSG) levels in renal slices were increased at 60 min by exposure to 0.25 mM PAP, while pyruvate prevented increased GSSG levels by PAP. Pyruvate also reduced the extent of 4-hydroxynonenal (4-HNE)-adducted proteins present after a 90-min incubation with PAP. These results indicate that pyruvate provided protection for PAP toxicity by providing an energy substrate and reducing oxidative stress

  10. Respon Akasia mangium dan Paraserianthes palcataria (Leguminocae terhadap inokulasi Rhizobium dalam hubungannya dengan kepadatan populasi Rhizobium tanah

    Directory of Open Access Journals (Sweden)

    Suliasih Suliasih

    1997-12-01

    Full Text Available The research aimed to discover the response of the fast growing tree legume to Rhizobium inoculation in relation to the population density of soil Rhizobium (indigenous rhizobia. The density of soil Rhizobium bacteria was predicted based on a plant infection test by using the most probable number (MPN of soil bacteria. The experimental design used in this work was Completely Randomized Design with factorial provided and 4 replicates. The first factor of treatment were inoculation and uninoculation, and the second factor was soil taken from 5 locations in Cigaru and Jampang-Sukabumi villages. The response of the plant was marked by the increase of dry weigh of leaf, root, and number of root nodules. The result of this study showed that the plants planted in the soil media with 40 bacteria / gram soil.

  11. Draft Genome Sequence of the Nitrogen-Fixing Rhizobium sullae Type Strain IS123T Focusing on the Key Genes for Symbiosis with its Host Hedysarum coronarium L.

    Directory of Open Access Journals (Sweden)

    Gaurav Sablok

    2017-07-01

    Full Text Available The prominent feature of rhizobia is their molecular dialogue with plant hosts. Such interaction is enabled by the presence of a series of symbiotic genes encoding for the synthesis and export of signals triggering organogenetic and physiological responses in the plant. The genome of the Rhizobium sullae type strain IS123T nodulating the legume Hedysarum coronarium, was sequenced and resulted in 317 scaffolds for a total assembled size of 7,889,576 bp. Its features were compared with those of genomes from rhizobia representing an increasing gradient of taxonomical distance, from a conspecific isolate (Rhizobium sullae WSM1592, to two congeneric cases (Rhizobium leguminosarum bv. viciae and Rhizobium etli and up to different genera within the legume-nodulating taxa. The host plant is of agricultural importance, but, unlike the majority of other domesticated plant species, it is able to survive quite well in the wild. Data showed that that the type strain of R. sullae, isolated from a wild host specimen, is endowed with a richer array of symbiotic genes in comparison to other strains, species or genera of rhizobia that were rescued from domesticated plant ecotypes. The analysis revealed that the bacterium by itself is incapable of surviving in the extreme conditions that its host plant can tolerate. When exposed to drought or alkaline condition, the bacterium depends on its host to survive. Data are consistent with the view of the plant phenotype as the primary factor enabling symbiotic nitrogen fixing bacteria to survive in otherwise limiting environments.

  12. Molecular markers to study competition and diversity of Rhizobium

    NARCIS (Netherlands)

    Sessitsch, A.

    1997-01-01

    The research described in this thesis was directed to the development of molecular identification and detection techniques for studying the ecology of Rhizobium, a nitrogen- fixing bacterium of agricultural importance. Competition of inoculant strains with indigenous

  13. Determination of effectiveness of native rhizobium on nodulation ...

    African Journals Online (AJOL)

    KARACA

    2012-05-08

    May 8, 2012 ... SINET: Ethiopian J. Sci. 24: 197-211. Beck DP, Materon LA, Afandi F (1993). Practical Rhizobium sp. legume technology manual. Int. Center Agric. Res. Dry Areas. Aleppo, Syria. pp. 1-54. Bouyoucos CA (1951). Hidrometer method improved for making particle size analysis of Soil. Agron. J. 54(5): 464-465.

  14. The rhizobium-pea symbiosis as affected by high temperatures

    NARCIS (Netherlands)

    Frings, J.F.J.

    1976-01-01

    A study has been made concerning the effect of high temperatures on the symbiosis of Rhizobium leguminosarum and pea plants (Pisum sativum). At 30°C, no nodules were found on the roots of plants growing in nutrient solution after inoculation with

  15. Dissecting hormonal pathways in nitrogen-fixing rhizobium symbioses

    NARCIS (Netherlands)

    Zeijl, van Arjan

    2017-01-01

    Nitrogen is a key element for plant growth. To meet nitrogen demands, some plants establish an endosymbiotic relationship with nitrogen-fixing rhizobium or Frankia bacteria. This involves formation of specialized root lateral organs, named nodules. These nodules are colonized

  16. effect of tillage, rhizobium inoculation in maize-soybean- based ...

    African Journals Online (AJOL)

    main plot, four rhizobium inoculation in soybean-maize-based cropping systems ... production systems, such as cropping systems, ... of commercial inoculants. Studies ... and distributed by IITA business incubation ... sowing, while the remaining part (2/3) was done as ...... biological nitrogen fixation potential and grain yield.

  17. Strain identification in Rhizobium by starch gel electrophoresis of isoenzymes

    DEFF Research Database (Denmark)

    Engvild, Kjeld Christensen; Nielsen, G.

    1985-01-01

    Sonieated extracts of rhizobia, especiaUy Rhizobium leguminosarum from pea and vetch, were run in horizontal starch gel electrophoresis in the cold. The rhizobia were grown on agar on a slime suppressing substrate of tryptone-yeast extract-CaCl2 with small amounts of mannitol, sorbitol...

  18. Cost effective pilot scale production of biofertilizer using Rhizobium ...

    African Journals Online (AJOL)

    We standardized the protocol for pilot scale production of Rhizobium and Azotobacter biofertilizer technology using region specific and environmental stress compatible strains isolated from various agro climatic regions of Odisha, India. The cost benefit of biofertilizer production through a cottage industry is also presented.

  19. Dynamics of pyruvate metabolism in Lactococcus lactis

    DEFF Research Database (Denmark)

    Melchiorsen, Claus Rix; Jensen, Niels B.S.; Christensen, Bjarke

    2001-01-01

    The pyruvate metabolism in the lactic acid bacterium Lactococcus lactis was studied in anaerobic cultures under transient conditions. During growth of L. lactis in continuous culture at high dilution rate, homolactic product formation was observed, i.e., lactate was produced as the major end...... product. At a lower dilution rate, the pyruvate metabolism shifted towards mixed acid-product formation where formate, acetate, and ethanol were produced in addition to lactate. The regulation of the shift in pyruvate metabolism was investigated by monitoring the dynamic behavior of L. lactis...

  20. Cultivation of parasitic leptospires: effect of pyruvate.

    Science.gov (United States)

    Johnson, R C; Walby, J; Henry, R A; Auran, N E

    1973-07-01

    Sodium pyruvate (100 mug/ml) is a useful addition to the Tween 80-albumin medium for the cultivation of parasitic serotypes. It is most effective in promoting growth from small inocula and growth of the nutritionally fastidious serotypes.

  1. Pyruvate transport by thermogenic-tissue mitochondria.

    OpenAIRE

    Proudlove, M O; Beechey, R B; Moore, A L

    1987-01-01

    1. Mitochondria isolated from the thermogenic spadices of Arum maculatum and Sauromatum guttatum plants oxidized external NADH, succinate, citrate, malate, 2-oxoglutarate and pyruvate without the need to add exogenous cofactors. 2. Oxidation of substrates was virtually all via the alternative oxidase, the cytochrome pathway constituting only 10-20% of the total activity, depending on the stage of spadix development. 3. During later stages of spadix development, pyruvate oxidation was enhanced...

  2. Phosphorylation site on yeast pyruvate dehydrogenase complex

    International Nuclear Information System (INIS)

    Uhlinger, D.J.

    1986-01-01

    The pyruvate dehydrogenase complex was purified to homogeneity from baker's yeast (Saccharomyces cerevisiae). Yeast cells were disrupted in a Manton-Gaulin laboratory homogenizer. The pyruvate dehydrogenase complex was purified by fractionation with polyethylene glycol, isoelectric precipitation, ultracentrifugation and chromatography on hydroxylapatite. Final purification of the yeast pyruvate dehydrogenase complex was achieved by cation-exchange high pressure liquid chromatography (HPLC). No endogenous pyruvate dehydrogenase kinase activity was detected during the purification. However, the yeast pyruvate dehydrogenase complex was phosphorylated and inactivated with purified pyruvate dehydrogenase kinase from bovine kidney. Tryptic digestion of the 32 P-labeled complex yielded a single phosphopeptide which was purified to homogeniety. The tryptic digest was subjected to chromatography on a C-18 reverse phase HPLC column with a linear gradient of acetonitrile. Radioactive fractions were pooled, concentrated, and subjected to anion-exchange HPLC. The column was developed with a linear gradient of ammonium acetate. Final purification of the phosphopeptide was achieved by chromatography on a C-18 reverse phase HPLC column developed with a linear gradient of acetonitrile. The amino acid sequence of the homogeneous peptide was determined by manual modified Edman degradation

  3. Crystal structure of Cryptosporidium parvum pyruvate kinase.

    Directory of Open Access Journals (Sweden)

    William J Cook

    Full Text Available Pyruvate kinase plays a critical role in cellular metabolism of glucose by serving as a major regulator of glycolysis. This tetrameric enzyme is allosterically regulated by different effector molecules, mainly phosphosugars. In response to binding of effector molecules and substrates, significant structural changes have been identified in various pyruvate kinase structures. Pyruvate kinase of Cryptosporidium parvum is exceptional among known enzymes of protozoan origin in that it exhibits no allosteric property in the presence of commonly known effector molecules. The crystal structure of pyruvate kinase from C. parvum has been solved by molecular replacement techniques and refined to 2.5 Å resolution. In the active site a glycerol molecule is located near the γ-phosphate site of ATP, and the protein structure displays a partially closed active site. However, unlike other structures where the active site is closed, the α6' helix in C. parvum pyruvate kinase unwinds and assumes an extended conformation. In the crystal structure a sulfate ion is found at a site that is occupied by a phosphate of the effector molecule in many pyruvate kinase structures. A new feature of the C. parvum pyruvate kinase structure is the presence of a disulfide bond cross-linking the two monomers in the asymmetric unit. The disulfide bond is formed between cysteine residue 26 in the short N-helix of one monomer with cysteine residue 312 in a long helix (residues 303-320 of the second monomer at the interface of these monomers. Both cysteine residues are unique to C. parvum, and the disulfide bond remained intact in a reduced environment. However, the significance of this bond, if any, remains unknown at this time.

  4. Molecular and Physiological Logics of the Pyruvate-Induced Response of a Novel Transporter in Bacillus subtilis.

    Science.gov (United States)

    Charbonnier, Teddy; Le Coq, Dominique; McGovern, Stephen; Calabre, Magali; Delumeau, Olivier; Aymerich, Stéphane; Jules, Matthieu

    2017-10-03

    /export system specific for pyruvate, PftAB, which defines a novel class of transporter. In this bacterium, extracellular pyruvate acts as the signal molecule for the LytST two-component system (TCS), which in turn induces expression of PftAB. However, when the pyruvate influx is high, LytST activity is drastically retroinhibited. Such a retroinhibition challenges the rational design of novel nature-inspired sensors and synthetic switches but undoubtedly offers new possibilities for the development of integrated sensor/controller circuitry. Copyright © 2017 Charbonnier et al.

  5. Rhizobium pongamiae sp. nov. from Root Nodules of Pongamia pinnata

    Directory of Open Access Journals (Sweden)

    Vigya Kesari

    2013-01-01

    Full Text Available Pongamia pinnata has an added advantage of N2-fixing ability and tolerance to stress conditions as compared with other biodiesel crops. It harbours “rhizobia” as an endophytic bacterial community on its root nodules. A gram-negative, nonmotile, fast-growing, rod-shaped, bacterial strain VKLR-01T was isolated from root nodules of Pongamia that grew optimal at 28°C, pH 7.0 in presence of 2% NaCl. Isolate VKLR-01 exhibits higher tolerance to the prevailing adverse conditions, for example, salt stress, elevated temperatures and alkalinity. Strain VKLR-01T has the major cellular fatty acid as C18:1  ω7c (65.92%. Strain VKLR-01T was found to be a nitrogen fixer using the acetylene reduction assay and PCR detection of a nifH gene. On the basis of phenotypic, phylogenetic distinctiveness and molecular data (16S rRNA, recA, and atpD gene sequences, G + C content, DNA-DNA hybridization etc., strain VKLR-01T = (MTCC 10513T = MSCL 1015T is considered to represent a novel species of the genus Rhizobium for which the name Rhizobium pongamiae sp. nov. is proposed. Rhizobium pongamiae may possess specific traits that can be transferred to other rhizobia through biotechnological tools and can be directly used as inoculants for reclamation of wasteland; hence, they are very important from both economic and environmental prospects.

  6. Coevolutionary genetic variation in the legume-rhizobium transcriptome.

    Science.gov (United States)

    Heath, Katy D; Burke, Patricia V; Stinchcombe, John R

    2012-10-01

    Coevolutionary change requires reciprocal selection between interacting species, where the partner genotypes that are favoured in one species depend on the genetic composition of the interacting species. Coevolutionary genetic variation is manifested as genotype × genotype (G × G) interactions for fitness in interspecific interactions. Although quantitative genetic approaches have revealed abundant evidence for G × G interactions in symbioses, the molecular basis of this variation remains unclear. Here we study the molecular basis of G × G interactions in a model legume-rhizobium mutualism using gene expression microarrays. We find that, like quantitative traits such as fitness, variation in the symbiotic transcriptome may be partitioned into additive and interactive genetic components. Our results suggest that plant genetic variation had the largest influence on nodule gene expression and that plant genotype and the plant genotype × rhizobium genotype interaction determine global shifts in rhizobium gene expression that in turn feedback to influence plant fitness benefits. Moreover, the transcriptomic variation we uncover implicates regulatory changes in both species as drivers of symbiotic gene expression variation. Our study is the first to partition genetic variation in a symbiotic transcriptome and illuminates potential molecular routes of coevolutionary change. © 2012 Blackwell Publishing Ltd.

  7. Microorganisms and methods for producing pyruvate, ethanol, and other compounds

    Energy Technology Data Exchange (ETDEWEB)

    Reed, Jennifer L.; Zhang, Xiaolin

    2017-12-26

    Microorganisms comprising modifications for producing pyruvate, ethanol, and other compounds. The microorganisms comprise modifications that reduce or ablate activity of one or more of pyruvate dehydrogenase, 2-oxoglutarate dehydrogenase, phosphate acetyltransferase, acetate kinase, pyruvate oxidase, lactate dehydrogenase, cytochrome terminal oxidase, succinate dehydrogenase, 6-phosphogluconate dehydrogenase, glutamate dehydrogenase, pyruvate formate lyase, pyruvate formate lyase activating enzyme, and isocitrate lyase. The microorganisms optionally comprise modifications that enhance expression or activity of pyruvate decarboxylase and alcohol dehydrogenase. The microorganisms are optionally evolved in defined media to enhance specific production of one or more compounds. Methods of producing compounds with the microorganisms are provided.

  8. Preliminary data on some correlations of Rhizobium and radio-stimulation seed treatments

    International Nuclear Information System (INIS)

    Soos, T.; Toth, J.; Manninger, E.

    1979-01-01

    The seeds of peas, beans, soy-beans and lucerne were treated with 60 Co-irradiation (4-10 Gray). The size of the roots and the quantity of seed-crop were measured. Irradiation by itself had no significant effect. Treatment with Rhizobium bacteria and with Rhizobium plus irradiation had considerable positive effects. (L.E.)

  9. Effects of nano-TiO2 on the agronomically-relevant Rhizobium-legume symbiosis

    Science.gov (United States)

    The impact of nano-TiO2 on Rhizobium-legume symbiosis was studied using garden peas and the compatible bacterial partner Rhizobium leguminosarum bv. viciae 3841. Exposure to nano-TiO2 did not affect the germination of peas grown aseptically, nor did it impact the gross root structure. However, nano-...

  10. Identification and characterization of symbiotic genes on the Rhizobium leguminosarum pre sym-plasmid

    NARCIS (Netherlands)

    Schetgens, T.M.P.

    1986-01-01

    Bacteria of the genera Rhizobium and Bradyrhizobium are unique in their quality to form nitrogen-fixing root nodules in symbiosis with leguminous plants. In fast-growing Rhizobium bacteria the genes involved in host recognition and nodule

  11. Studies on the expression of plasmid-borne genes in the endosymbiotic state of Rhizobium leguminosarum

    NARCIS (Netherlands)

    Krol, A.J.M.

    1982-01-01

    The subject matter of the research reported in this thesis is the role of plasmid-borne genes of Rhizobium in symbiosis and nitrogen fixation. Plasmid DNA was isolated from Rhizobium leguminosarum strain PRE and the expression of plasmid DNA in nitrogen

  12. Effects of nano-ZnO on the agronomically relevant Rhizobium-legume symbiosis

    Science.gov (United States)

    The impact of nano-ZnO (nZnO) on Rhizobium-legume symbiosis was studied with garden pea and its compatible bacterial partner Rhizobium leguminosarum bv. viciae 3841. Exposure of peas to nZnO had no impact on germination, but significantly affected root length. Chronic exposure of plant to nZnO impac...

  13. LysM-Type Mycorrhizal Receptor Recruited for Rhizobium Symbiosis in Nonlegume Parasponia

    NARCIS (Netherlands)

    Camp, Op den R.H.M.; Streng, A.J.; Mita, De S.; Cao, Q.; Polone, E.; Liu, W.; Ammiraju, J.S.S.; Kudrna, D.; Wing, R.; Untergasser, A.; Bisseling, T.; Geurts, R.

    2011-01-01

    Rhizobium root nodule symbiosis is generally considered to be unique for legumes. However, there is one exception and that is Parasponia. In this nonlegume, the rhizobial nodule symbiosis evolved independently and is, like in legumes, induced by rhizobium Nod factors. We used Parasponia to identify

  14. Modeling of the pyruvate production with Escherichia coli: comparison of mechanistic and neural networks-based models.

    Science.gov (United States)

    Zelić, B; Bolf, N; Vasić-Racki, D

    2006-06-01

    Three different models: the unstructured mechanistic black-box model, the input-output neural network-based model and the externally recurrent neural network model were used to describe the pyruvate production process from glucose and acetate using the genetically modified Escherichia coli YYC202 ldhA::Kan strain. The experimental data were used from the recently described batch and fed-batch experiments [ Zelić B, Study of the process development for Escherichia coli-based pyruvate production. PhD Thesis, University of Zagreb, Faculty of Chemical Engineering and Technology, Zagreb, Croatia, July 2003. (In English); Zelić et al. Bioproc Biosyst Eng 26:249-258 (2004); Zelić et al. Eng Life Sci 3:299-305 (2003); Zelić et al Biotechnol Bioeng 85:638-646 (2004)]. The neural networks were built out of the experimental data obtained in the fed-batch pyruvate production experiments with the constant glucose feed rate. The model validation was performed using the experimental results obtained from the batch and fed-batch pyruvate production experiments with the constant acetate feed rate. Dynamics of the substrate and product concentration changes was estimated using two neural network-based models for biomass and pyruvate. It was shown that neural networks could be used for the modeling of complex microbial fermentation processes, even in conditions in which mechanistic unstructured models cannot be applied.

  15. Cultivation of Parasitic Leptospires: Effect of Pyruvate

    Science.gov (United States)

    Johnson, R. C.; Walby, J.; Henry, R. A.; Auran, N. E.

    1973-01-01

    Sodium pyruvate (100 μg/ml) is a useful addition to the Tween 80-albumin medium for the cultivation of parasitic serotypes. It is most effective in promoting growth from small inocula and growth of the nutritionally fastidious serotypes. Images PMID:4580191

  16. Assessment of Qualitative and Quantitative Characters of Two Persian Clover Ecotypes Inoculated by Rhizobium leguminosarum biovartrifoli and Pesudomonas putida Bacteria

    Directory of Open Access Journals (Sweden)

    R Azamei

    2016-02-01

    the powder used for inoculum was 5 gram from every bacterium seed (Containing 108 × 5 bacteria per gram for 100 kg seed. For better adhesion of the bacteria on the surface of seed, water with 20% sugar solution was used. (2 Sampling performed by harvesting 2 meter of every plot and 2 kg of fresh yield was transferred to oven (48 hours with (72 °C to determine dry matter. The crude protein content was determined by multiplying nitrogen content by the correction factor (6.25. At the end of the season a few plants from each plot were selected, and the number of nodules formed on the roots were counted and secondary roots with the highest penetration depth were measured by ruler. Analysis of variance and the means of treatments were performed using SAS software. Average interaction MSTAT- C treatments were performed using the software and the treatments were compared based on Duncan method. Results and Discussion The results showed that the qualitative factors have not been affected by Rhizobium and Pseudomonas bacteria so that the differences between treated plots with control were not significant. The quantitative factors except for depth of root penetration were affected by inoculation with Rhizobium and Pseudomonas bacteria and a significant difference between treated plots and control was obtained. Roberts et al. (3 reported that delay in planting caused plant growth exposure to high temperatures and long days, thus cell walls were stimulated to increase fiber and protein content and consequently digestibility was extremely reduced. The results indicated that inoculation by both bacteria (Rhizobium and Pseudomonas has affected quantitative indicators of growth significantly and increased fresh and dry yield, plant height, leaf/stem ratio and the number of nodes on roots. However the results showed that the qualitative characteristics and root infiltration did not change significantly by inoculation of both bacteria. Plant growth promoting rhizobacteria (PGPR leaded

  17. Studies to enhance the hyperpolarization level in PHIP-SAH-produced C13-pyruvate

    Science.gov (United States)

    Cavallari, Eleonora; Carrera, Carla; Aime, Silvio; Reineri, Francesca

    2018-04-01

    The use of [1-13C]pyruvate, hyperpolarized by dissolution-Dynamic Nuclear Polarization (d-DNP), in in vivo metabolic studies has developed quickly, thanks to the imaging probe's diagnostic relevance. Nevertheless, the cost of a d-DNP polarizer is quite high and the speed of hyperpolarization process is relatively slow, meaning that its use is limited to few research laboratories. ParaHydrogen Induced Polarization Side Arm Hydrogenation (PHIP-SAH) (Reineri et al., 2015) is a cost effective and easy-to-handle method that produces 13C-MR hyperpolarization in [1-13C]pyruvate and other metabolites. This work aims to identify the main determinants of the hyperpolarization levels observed in C13-pyruvate using this method. By dissecting the various steps of the PHIP-SAH procedure, it has been possible to assess the role of several experimental parameters whose optimization must be pursued if this method is to be made suitable for future translational steps. The search for possible solutions has led to improvements in the polarization of sodium [1-13C]pyruvate from 2% to 5%. Moreover, these results suggest that observed polarization levels could be increased considerably by an automatized procedure which would reduce the time required for the work-up passages that are currently carried out manually. The results reported herein mean that the attainment of polarization levels suitable for the metabolic imaging applications of these hyperpolarized substrates show significant promise.

  18. Compartmented pyruvate in perfused working heart

    International Nuclear Information System (INIS)

    Buenger, R.

    1985-01-01

    Pyruvate compartmentation and lactate dehydrogenase (LDH) were studied in isolated perfused working guinea pig hearts. The mean intracellular pyruvate (Pyr) contents increased with perfusate Pyr (0-2 mM) but varied only slightly with glucose (0-10 mM) and additional insulin (0.04-5 U/l), respectively. With 5-10 mM glucose plus 5 U/l insulin, but not with Pyr or lactate (Lac) as substrates, a near equilibrium between the LDH and the glycerol-3-phosphate dehydrogenase seemed to exist. Evidence for an inhibitory effect of Pyr on the activity of the LDH system of the perfused hearts was not obtained. With [U- 14 C]glucose as sole substrate, the specific activity of coronary venous Lac was near half that of precursor glucose. 14 CO 2 production was thus in quantitative agreement with rates of pyruvate oxidation that were determined as glucose uptake minus (Pyr + Lac) release. In contrast, with 0.2 mM [1- 14 C]Pyr plus 5 mM glucose, the ratio of 14 CO 2 production to specific activity of Lac overestimated Pyr oxidation judged from myocardial substrate balances and O 2 uptake, respectively; here, at least three pools of [ 14 C]HCO-3 and [ 14 C]lac, respectively, were kinetically demonstrable during washout of trace amounts of 14 C-labeled Pyr. Evidently, the specific activity of Lac was equivalent to that of mitochondrial oxidized Pyr provided [ 14 C]glucose was the sole or major precursor of cellular pyruvate. However, exogenously applied [1- 14 C]Pyr of high specific activity seemed to induce intracellular formation of both a highly and lowly labeled Pyr; the latter Pyr compartment did not seem in ready equilibrium with the cell physiologically prevailing highly labeled Pyr pool

  19. Loss of Mitochondrial Pyruvate Carrier 2 in Liver Leads to Defects in Gluconeogenesis and Compensation via Pyruvate-Alanine Cycling

    Science.gov (United States)

    McCommis, Kyle S.; Chen, Zhouji; Fu, Xiaorong; McDonald, William G.; Colca, Jerry R.; Kletzien, Rolf F.; Burgess, Shawn C.; Finck, Brian N.

    2015-01-01

    SUMMARY Pyruvate transport across the inner mitochondrial membrane is believed to be a prerequisite step for gluconeogenesis in hepatocytes, which is important for maintenance of normoglycemia during prolonged food deprivation, but also contributes to hyperglycemia in diabetes. To determine the requirement for mitochondrial pyruvate import in gluconeogenesis, mice with liver-specific deletion of mitochondrial pyruvate carrier 2 (LS-Mpc2−/−) were generated. Loss of MPC2 impaired, but did not completely abolish, hepatocyte pyruvate metabolism, labelled pyruvate conversion to TCA cycle intermediates and glucose, and glucose production from pyruvate. Unbiased metabolomic analyses of livers from fasted LS-Mpc2−/− mice suggested that alterations in amino acid metabolism, including pyruvate-alanine cycling, might compensate for loss of MPC2. Indeed, inhibition of pyruvate-alanine transamination further reduced mitochondrial pyruvate metabolism and glucose production by LS-Mpc2−/− hepatocytes. These data demonstrate an important role for MPC2 in controlling hepatic gluconeogenesis and illuminate a compensatory mechanism for circumventing a block in mitochondrial pyruvate import. PMID:26344101

  20. Entrapment of Rhizobium sp. by fluidized bed technique using polymers as coating materials

    Directory of Open Access Journals (Sweden)

    Diego Rivera

    2016-04-01

    Full Text Available The spray-drying technique was applied for the development of three solid formulations of Rhizobium. Sodium alginate and hydroxypropyl methylcellulose (HPMC with concentrations of 0.5 % were used as polymers. Results showed that none of the solid formulations had negative effects in vitro on the growth-promoting capacities of Rhizobium sp. G58 (p < 0.05. PCA´s first three components explained 84.5 % of the total variance. This analysis concluded that the solid formulation had not negative effects on the biological nitrogen fixation activity in vitro or on the process of nodulation in greenhouse experiments. Symbiosis between Rhizobium and the plant was effective, which suggested that, under controlled conditions, the coating process with the polymers had allowed a controlled release of the bacteria and a proper transfer of Rhizobium sp. from the microparticles to the root of the plant.

  1. Permanent draft genome of the malachite-green-tolerant bacterium Rhizobium sp. MGL06.

    Science.gov (United States)

    Liu, Yang; Wang, Runping; Zeng, Runying

    2014-12-01

    Rhizobium sp. MGL06, the first Rhizobium isolate from a marine environment, is a malachite-green-tolerant bacterium with a broader salinity tolerance (range: 0.5% to 9%) than other rhizobia. This study sequences and annotates the draft genome sequence of this strain. Genome sequence information provides a basis for analyzing the malachite green tolerance, broad salinity adaptation, nitrogen fixation properties, and taxonomic classification of the isolate. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Influence of arbuscular mycorrhizal fungi, rhizobium inoculation and rock phosphate on growth and quality of lentil

    International Nuclear Information System (INIS)

    Yaseen, T.; Ali, K.

    2016-01-01

    Effective inoculation of legumes has the ability not only to ensure nutrients availability to plants particularly in N and P-limiting (due to improvement in nutrients fixation) environments but also can manipulate the environmental hazards associated with over inorganic fertilization. To support this view, the current experiment was conducted to study the influence of rock phosphorus fertilization, Arbuscular Mycorrhizae (AM) and Rhizobium inoculation on growth and yield parameters of Lens culinaris (NARC.2008-4). In addition, the current experiments aimed to evaluate the effect of different inoculation practices on crop quality in comparison with control (no inoculation).The experiment was laid out in randomized complete block design with four replications during winter (2010-11 and 2012-13) at the Department of Botany University of Peshawar Pakistan. Overall, inoculated plant performed superior in terms of plant growth and quality over control. All plants measured parameters (Leaf chlorophyll content, seed protein, fiber and ash content, plant height, number of seed pod-1, leaves plant-1, flowers plant-1, pods plant-1, pod length and thousand seed weight) were highest in plant samples inoculated with VAM and Rhizobium in combination as compared to sole application of VAM or Rhizobium. Combined inoculation of VAM and Rhizobium caused 10, 24, 17, 21 and 14% increase in seed protein content, leaf chlorophyll content, seed fiber content, seed ash content and number of seed pod-1 over sole application of VAM and Rhizobium when averaged over two years. Combined application of Rhizobium + VAM enhanced seed yield plant-1 by 45% over control and 24% and 28% over sole inoculation of VAM and Rhizobium respectively. It is therefore concluded that dual inoculation of VAM + Rhizobium and rock phosphate may be of only limited consequence in high input agricultural systems. (author)

  3. Differences between strains of Rhizobium in sensitivity to canavanine

    Energy Technology Data Exchange (ETDEWEB)

    Weaks, T E [Marshall Univ., Huntingdon, West Virginia (USA). Dept. of Biological Sciences

    1977-11-01

    Four strains of rhizobia that nodulate canavanine-synthesizing legumes and four strains that nodulate noncanavanine-synthesizing legumes were tested for sensitivity to L-canavanine. The effect of canavanine on growth depends upon the strain of Rhizobium tested rather than the canavanine synthesizing capability of the host legume. In both groups of rhizobia, some strains were inhibited in growth by canavanine. Canavanine enhancement of growth was observed in rhizobia that nodulate noncanavanine-synthesizing legumes. Canavanine was found to enhance the incorporation of /sup 3/H-uridine and /sup 3/H-L-leucine into trichloroacetic acid insoluble fractions of starved cells of two strains of rhizobia tested. This demonstrated that under certain conditions, some rhizobia can detoxify canavanine and utilize it in synthetic processes.

  4. Ethyl pyruvate protects colonic anastomosis from ischemia-reperfusion injury.

    Science.gov (United States)

    Unal, B; Karabeyoglu, M; Huner, T; Canbay, E; Eroglu, A; Yildirim, O; Dolapci, M; Bilgihan, A; Cengiz, O

    2009-03-01

    Ethyl pyruvate is a simple derivative in Ca(+2)- and K(+)-containing balanced salt solution of pyruvate to avoid the problems associated with the instability of pyruvate in solution. It has been shown to ameliorate the effects of ischemia-reperfusion (I/R) injury in many organs. It has also been shown that I/R injury delays the healing of colonic anastomosis. In this study, the effect of ethyl pyruvate on the healing of colon anastomosis and anastomotic strength after I/R injury was investigated. Anastomosis of the colon was performed in 32 adult male Wistar albino rats divided into 4 groups of 8 individuals: (1) sham-operated control group (group 1); (2) 30 minutes of intestinal I/R by superior mesenteric artery occlusion (group 2); (3) I/R+ ethyl pyruvate (group 3), ethyl pyruvate was administered as a 50-mg/kg/d single dose; and (4) I/R+ ethyl pyruvate (group 4), ethyl pyruvate administration was repeatedly (every 6 hours) at the same dose (50 mg/kg). On the fifth postoperative day, animals were killed. Perianastomotic tissue hydroxyproline contents and anastomotic bursting pressures were measured in all groups. When the anastomotic bursting pressures and tissue hydroxyproline contents were compared, it was found that they were decreased in group 2 when compared with groups 1, 3, and 4 (P .05). Ethyl pyruvate significantly prevents the delaying effect of I/R injury on anastomotic strength and healing independent from doses of administration.

  5. Pyruvate carboxylase is expressed in human skeletal muscle

    DEFF Research Database (Denmark)

    Minet, Ariane D; Gaster, Michael

    2010-01-01

    Pyruvate carboxylase (PC) is a mitochondrial enzyme that catalyses the carboxylation of pyruvate to oxaloacetate thereby allowing supplementation of citric acid cycle intermediates. The presence of PC in skeletal muscle is controversial. We report here, that PC protein is easily detectable...

  6. Production and Recovery of Pyruvic Acid: Recent Advances

    Science.gov (United States)

    Pal, Dharm; Keshav, Amit; Mazumdar, Bidyut; Kumar, Awanish; Uslu, Hasan

    2017-12-01

    Pyruvic acid is an important keto-carboxylic acid and can be manufactured by both chemical synthesis and biotechnological routes. In the present paper an overview of recent developments and challenges in various existing technique for the production and recovery of pyruvic acid from fermentation broth or from waste streams has been presented. The main obstacle in biotechnological production of pyruvic acid is development of suitable microorganism which can provide high yield and selectivity. On the other hand, technical limitation in recovery of pyruvic acid from fermentation broth is that, it could not be separated as other carboxylic acid in the form of salts by addition of alkali. Besides, pyruvic acid cannot be crystallized. Commercial separation by distillation is very expensive because pyruvic acid decomposes at higher temperature. It is also chemically reactive due to its peculiar molecular structure and has tendency to polymerize. Thus, at high concentration the various type of reaction leads to lower yield of the product, and hence, conventional methods are not favorable. Alternate separation technologies viable to both synthetic and biological routes are the current research areas. Latest techniques such as reactive extraction is new to the field of recovery of pyruvic acid. Recent development and future prospects in downstream processing of biochemically produced pyruvic acids has been discussed in this review article.

  7. The use of mycorrhiza and Rhizobium in the growth of three months saga seedling (Adenanthera pavonina

    Directory of Open Access Journals (Sweden)

    Rina Kurniaty

    2017-03-01

    Full Text Available Abstrak. Kurniaty R. 2016. The use of mycorrhiza and Rhizobium in the growth of three months saga seedling (Adenanthera pavonina. Pros Sem Nas Masy Biodiv Indon 2: 6-9. Plants saga tree (Adenanthera pavonina having benefits versatile because almost all parts of crop can be used so that economically valuable high. Wood saga can be used as building material and furniture . Seeds saga have the potential who has a promising as renewable energy source of them because the seeds his containing 14-28% fatty oil who could be classified as non food . In addition oil derived from the seeds of the saga is also very good to treat a disease in, scurvy, injuries, making candles, batik industry, and materials making soap. Research aims to understand the influence of the use of mycorrhizal and Rhizobium in growth seedlings saga age 3 months. Inoculating Rhizobium liquid as many as 1 mL by means of injecting on roots and plants surrounding the hole . The provision of mycorrhizal done by entering 2 g mycorrhizal (Glomus sp into a hole plant at the same time as Rhizobium. Design used is a random factorials consisting of two factors treatment. The first is Rhizobium (A namely: A1 = control and A2= Rhizobium sp. The second factor is mycorrhizal (B consisting of two the standard: B1 = control and B2 = Glomus sp (2 g/ polybag. The results showed that the treatment A2B2 (Rhizobium + mycorrhizal put a value colonization roots highest namely 68,88% with live percent 99,26%, height 10,08 cm, diameter 1.67mm, biomass 0,56 g, TR ratio 2.01 and IMB 0,06 . Nutrient absorption, treatment A2B2 is the nutrient in N 60,30% compared to control, the nutrient P 66,66% compared to control and the nutrient K 123,17% compared to control.

  8. The Role of Pyruvate Dehydrogenase Kinase in Diabetes and Obesity

    Directory of Open Access Journals (Sweden)

    In-Kyu Lee

    2014-06-01

    Full Text Available The pyruvate dehydrogenase complex (PDC is an emerging target for the treatment of metabolic syndrome. To maintain a steady-state concentration of adenosine triphosphate during the feed-fast cycle, cells require efficient utilization of fatty acid and glucose, which is controlled by the PDC. The PDC converts pyruvate, coenzyme A (CoA, and oxidized nicotinamide adenine dinucleotide (NAD+ into acetyl-CoA, reduced form of nicotinamide adenine dinucleotide (NADH, and carbon dioxide. The activity of the PDC is up- and down-regulated by pyruvate dehydrogenase kinase and pyruvate dehydrogenase phosphatase, respectively. In addition, pyruvate is a key intermediate of glucose oxidation and an important precursor for the synthesis of glucose, glycerol, fatty acids, and nonessential amino acids.

  9. An improved method for the assay of platelet pyruvate dehydrogenase

    International Nuclear Information System (INIS)

    Schofield, P.J.; Griffiths, L.R.; Rogers, S.H.

    1980-01-01

    An improved method for the assay of human platelet pyruvate dehydrogenase is described. By generating the substrate [1- 14 C]pyruvate in situ from [1- 14 C]lactate plus L-lactate dehydrogenase, the rate of spontaneous decarboxylation is dramatically reduced, allowing far greater sensitivity in the assay of low activities of pyruvate dehydrogenase. In addition, no special precautions are required for the storage and use of [1- 14 C]lactate, in contrast to those for [1- 14 C]pyruvate. These factors allow a 5-10-fold increase in sensitivity compared with current methods. The pyruvate dehydrogenase activity of normal subjects as determined by the [1- 14 C]lactate system was 215+-55 pmol min -1 mg -1 protein (n=18). The advantages of this assay system are discussed. (Auth.)

  10. Maize growth in response to Azospirillum brasilense, Rhizobium tropici, molybdenum and nitrogen

    Directory of Open Access Journals (Sweden)

    Angelita A. C. Picazevicz

    Full Text Available ABSTRACT The objective of this research was to evaluate the effect of Azospirillum brasilense, Rhizobium tropici, nitrogen (N and molybdenum (Mo fertilization on maize growth. The experiment was carried out in a greenhouse from October to November 2015, in a completely randomized design, in 2 x 2 x 2 x 5 factorial scheme, with 5 replicates, corresponding to the absence and presence of Azospirillum brasilense, Rhizobium tropici, N (30 kg ha-1 and five Mo doses (0, 7.5, 15.0, 22.5 and 30.0 g ha-1. The analyzed variables were: plant height, basal stem diameter, dry biomass of shoots, roots, total and N accumulated in the shoots. There was double or triple interaction between N fertilization, Azospirillum brasilense and Rhizobium tropici for the evaluated variables. However, isolated and/or combined effect of Mo was not observed. Seed inoculation with Azospirillum brasilense as well as their co-inoculation with Rhizobium tropici in the absence of N fertilization was efficient to increase plant growth. Soil N fertilization at sowing was less efficient in promoting plant growth than when it was combined with seed inoculation with Rhizobium tropici.

  11. Mapping the genetic basis of symbiotic variation in legume-rhizobium interactions in Medicago truncatula.

    Science.gov (United States)

    Gorton, Amanda J; Heath, Katy D; Pilet-Nayel, Marie-Laure; Baranger, Alain; Stinchcombe, John R

    2012-11-01

    Mutualisms are known to be genetically variable, where the genotypes differ in the fitness benefits they gain from the interaction. To date, little is known about the loci that underlie such genetic variation in fitness or whether the loci influencing fitness are partner specific, and depend on the genotype of the interaction partner. In the legume-rhizobium mutualism, one set of potential candidate genes that may influence the fitness benefits of the symbiosis are the plant genes involved in the initiation of the signaling pathway between the two partners. Here we performed quantitative trait loci (QTL) mapping in Medicago truncatula in two different rhizobium strain treatments to locate regions of the genome influencing plant traits, assess whether such regions are dependent on the genotype of the rhizobial mutualist (QTL × rhizobium strain), and evaluate the contribution of sequence variation at known symbiosis signaling genes. Two of the symbiotic signaling genes, NFP and DMI3, colocalized with two QTL affecting average fruit weight and leaf number, suggesting that natural variation in nodulation genes may potentially influence plant fitness. In both rhizobium strain treatments, there were QTL that influenced multiple traits, indicative of either tight linkage between loci or pleiotropy, including one QTL with opposing effects on growth and reproduction. There was no evidence for QTL × rhizobium strain or genotype × genotype interactions, suggesting either that such interactions are due to small-effect loci or that more genotype-genotype combinations need to be tested in future mapping studies.

  12. 3-Bromopyruvate antagonizes effects of lactate and pyruvate, synergizes with citrate and exerts novel anti-glioma effects.

    Science.gov (United States)

    El Sayed, S M; El-Magd, R M Abou; Shishido, Y; Chung, S P; Diem, T H; Sakai, T; Watanabe, H; Kagami, S; Fukui, K

    2012-02-01

    Oxidative stress-energy depletion therapy using oxidative stress induced by D-amino acid oxidase (DAO) and energy depletion induced by 3-bromopyruvate (3BP) was reported recently (El Sayed et al., Cancer Gene Ther., 19, 1-18, 2012). Even in the presence of oxygen, cancer cells oxidize glucose preferentially to produce lactate (Warburg effect) which seems vital for cancer microenvironment and progression. 3BP is a closely related structure to lactate and pyruvate and may antagonize their effects as a novel mechanism of its action. Pyruvate exerted a potent H(2)O(2) scavenging effect to exogenous H(2)O(2), while lactate had no scavenging effect. 3BP induced H(2)O(2) production. Pyruvate protected against H(2)O(2)-induced C6 glioma cell death, 3BP-induced C6 glioma cell death but not against DAO/D-serine-induced cell death, while lactate had no protecting effect. Lactate and pyruvate protected against 3BP-induced C6 glioma cell death and energy depletion which were overcome with higher doses of 3BP. Lactate and pyruvate enhanced migratory power of C6 glioma which was blocked by 3BP. Pyruvate and lactate did not protect against C6 glioma cell death induced by other glycolytic inhibitors e.g. citrate (inhibitor of phosphofructokinase) and sodium fluoride (inhibitor of enolase). Serial doses of 3BP were synergistic with citrate in decreasing viability of C6 glioma cells and spheroids. Glycolysis subjected to double inhibition using 3BP with citrate depleted ATP, clonogenic power and migratory power of C6 glioma cells. 3BP induced a caspase-dependent cell death in C6 glioma. 3BP was powerful in decreasing viability of human glioblastoma multiforme cells (U373MG) and C6 glioma in a dose- and time-dependent manner.

  13. Genetic Factors in Rhizobium Affecting the Symbiotic Carbon Costs of N2 Fixation and Host Plant Biomass Production

    DEFF Research Database (Denmark)

    Skøt, L.; Hirsch, P. R.; Witty, J. F.

    1986-01-01

    The effect of genetic factors in Rhizobium on host plant biomass production and on the carbon costs of N2 fixation in pea root nodules was studied. Nine strains of Rhizobium leguminosarum were constructed, each containing one of three symbiotic plasmids in combination with one of three different ...

  14. Cerebrospinal fluid lactate and pyruvate concentrations and their ratio.

    Science.gov (United States)

    Zhang, Wan-Ming; Natowicz, Marvin R

    2013-05-01

    Determinations of cerebrospinal fluid (CSF) lactate and pyruvate concentrations and CSF lactate:pyruvate (L/P) ratios are important in several clinical settings, yet published normative data have significant limitations. We sought to determine a large dataset of stringently-defined normative data for CSF lactate and pyruvate concentrations and CSF L/P ratios. We evaluated data from 627 patients who had determinations of CSF lactate and/or CSF pyruvate from 2001 to 2011 at the Cleveland Clinic. Inclusion in the normal reference population required normal CSF cell counts, glucose and protein and routine serum chemistries and absence of progressive brain disorder, epilepsy, or seizure within 24h. Brain MRI, if done, showed no evidence of tumor, acute changes or basal ganglia abnormality. CSF cytology, CSF alanine and immunoglobulin levels, and oligoclonal band analysis were required to be normal, if done. Various inclusion/exclusion criteria were compared. 92 patients fulfilled inclusion/exclusion criteria for a reference population. The 95% central intervals (2.5%-97.5%) for CSF lactate and pyruvate levels were 1.01-2.09mM and 0.03-0.15mM, respectively, and 9.05-26.37 for CSF L/P. There were no significant gender-related differences of CSF lactate or pyruvate concentrations or of CSF L/P. Weak positive correlations between the concentration of CSF lactate or pyruvate and age were noted. Using stringent inclusion/exclusion criteria, we determined normative data for CSF lactate and pyruvate concentrations and CSF L/P ratios in a large, well-characterized reference population. Normalcy of routine CSF and blood analytes are the most important parameters in determining reference intervals for CSF lactate and pyruvate. Copyright © 2012 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

  15. Effect of Rhizobium and Mycorhiza inoculation on the nursery growth of Acacia and Teline monspessulana

    International Nuclear Information System (INIS)

    Layton, G; Lozano de Yunda, A; Chaparro, H

    1999-01-01

    In an experiment accomplished in the tree nursery Tisquesusa located in Madrid (Cundinamarca) was evaluated the effect of the inoculation with strains selected of foreign and Indigenous rhizobium and Arbuscular mycorrhizal fungi am (Glomus folescutolum) on the growth, nitrogen fixation, and micorrization of Acacia (Acacia decurrens) and Retamo (Teline monspessulana) that they are used In soils recovery by the Corporacion Autonoma Regional de Cundinamarca CAR. The studied species presented positive response to the inoculation with rhizobium; the indigenous strain DQ6-09, isolated in Guatavita (Cundinamarca), presented the better results in Retamo and also in Acacia alone and in mixture with the foreign strain T1881. The inoculation with fungi AM increased the heights, dry weights, phosphorus content and percentage of micorrization in Acacia and Retamo. The double inoculation with fungi ma and rhizobium it did not increase the nitrogen fixing of Acacia while in Retamo was presented a positive effect with the strain DQ6-09

  16. The isolation, enumeration, and characterization of Rhizobium bacteria of the soil in Wamena Biological Garden

    Directory of Open Access Journals (Sweden)

    SRI PURWANINGSIH

    2005-04-01

    Full Text Available The eleven soil samples have been isolated and characterized. The aims of the study were to get the pure culture and some data which described about enumeration and especially their characters in relation to the acids and bases reaction in their growth. The isolation of the bacteria use Yeast Extract Mannitol Agar medium (YEMA while the characterization by using YEMA medium mixed with Brom Thymol Blue and Congo Red indicators respectively. The results showed that eighteen isolates have been isolated which consisted of three low growing and fifteen fast growing bacteria. Two isolates were not indicated Rhizobium and sixteen were Rhizobium. Density of Rhizobium enumeration was varied which related to soil organic matter content. The enumeration bacteria in YEMA medium were in the range of 0.6 x 105 and 11.6 x 105 CFU /g soil. The highest population was found in soil sample of Wieb vegetation.

  17. Rhizobium pusense sp. nov., isolated from the rhizosphere of chickpea (Cicer arietinum L.).

    Science.gov (United States)

    Panday, Digvijay; Schumann, Peter; Das, Subrata K

    2011-11-01

    A novel bacterial strain, designated NRCPB10(T), was isolated from rhizosphere soil of chickpea (Cicer arietinum L.) in Pusa, New Delhi, India. The 16S rRNA gene sequence of strain NRCPB10(T) showed highest similarity (98.9 %) to that of Rhizobium radiobacter NCPPB 2437(T), followed by Rhizobium larrymoorei AF3-10(T) (97.7 %) and Rhizobium rubi IFO 13261(T) (97.4 %). Phylogenetic analysis of strain NRCPB10(T) based on the housekeeping genes recA and atpD confirmed its position as distinct from recognized Rhizobium species. Levels of DNA-DNA relatedness between strain NRCPB10(T) and R. radiobacter ICMP 5785(T), R. larrymoorei LMG 21410(T) and R. rubi ICMP 6428(T) were 51.0, 32.6 and 27.3 %, respectively. Cellular fatty acids of strain NRCPB10(T) were C(18 : 1)ω7c (58.9 %), C(16 : 0) (15.5 %), C(19 : 0) cyclo ω8c (11.5 %), iso-C(16 : 1) (5.8 %), C(16 : 0) 3-OH (4.5 %), C(16 : 1)ω7c (2.1 %) and C(18 : 0) (1.3 %). The G+C content of the genomic DNA of strain NRCPB10(T) was 59.0 mol%. Strain NRCPB10(T) did not nodulate chickpea plants or induce tumours in tobacco plants. Phenotypic and physiological properties along with SDS-PAGE of whole-cell soluble proteins differentiated strain NRCPB10(T) from its closest phylogenetic neighbours. On the basis of data from the present polyphasic taxonomic study, strain NRCPB10(T) is considered to represent a novel species of the genus Rhizobium, for which the name Rhizobium pusense sp. nov. is proposed. The type strain is NRCPB10(T) ( = LMG 25623(T) = JCM 16209(T) = NCIMB 14639(T)).

  18. Influence of carbofuran on certain metabolic and symbiotic activities of a cowpea Rhizobium

    International Nuclear Information System (INIS)

    Palaniappan, S.; Balasubramanian, A.

    1983-01-01

    Using carbon 14 radioisotope an in-vitro study of the effect of insecticides, carbofuran, on the metabolic and symbiotic activities of Rhizobium sp. cowpea group, was carried out. The study indicated that at 10 ppm carbofuran inhibited the in-vitro growth of the bacterium, suppressed the oxidation of all the Trichloroacetic acid (TCA) cycle intermediates, significantly reduced glucose oxidation and translocation and affected the growth and symbiotic activities of the cowpea as reflected by a reduction in the dry matter production and total nitrogen content. The insecticide was itself degraded by the Rhizobium sp. within 30 days of incubation

  19. Phenotypic and molecular genetic analysis of Pyruvate Kinase ...

    African Journals Online (AJOL)

    Jaouani Mouna

    2015-09-26

    Sep 26, 2015 ... to several mutations at the Pyruvate Kinase gene (PKLR) located on chromosome .... Tunisians (Fig. 2) [21]. The screening of whole PKLR gene revealed the presence of ..... newborns: the pitfalls of diagnosis. J Pediatr 2007 ...

  20. Phenotypic and molecular genetic analysis of Pyruvate Kinase ...

    African Journals Online (AJOL)

    Phenotypic and molecular genetic analysis of Pyruvate Kinase deficiency in a Tunisian family. Jaouani Mouna, Hamdi Nadia, Chaouch Leila, Kalai Miniar, Mellouli Fethi, Darragi Imen, Boudriga Imen, Chaouachi Dorra, Bejaoui Mohamed, Abbes Salem ...

  1. Rhizobium altiplani sp. nov., isolated from effective nodules on Mimosa pudica growing in untypically alkaline soil in central Brazil.

    Science.gov (United States)

    Baraúna, Alexandre C; Rouws, Luc F M; Simoes-Araujo, Jean L; Dos Reis Junior, Fábio B; Iannetta, Pietro P M; Maluk, Marta; Goi, Silvia R; Reis, Veronica M; James, Euan K; Zilli, Jerri E

    2016-10-01

    Root nodule bacteria were isolated from nodules on Mimosa pudica L. growing in neutral-alkaline soils from the Distrito Federal in central Brazil. The 16S rRNA gene sequence analysis of 10 strains placed them into the genus Rhizobium with the closest neighbouring species (each with 99 % similarity) being Rhizobium grahamii, Rhizobium cauense, Rhizobium mesoamericanum and Rhizobium tibeticum. This high similarity, however, was not confirmed by multi-locus sequence analysis (MLSA) using three housekeeping genes (recA, glnII and rpoB), which revealed R. mesoamericanum CCGE 501T to be the closest type strain (92 % sequence similarity or less). Chemotaxonomic data, including fatty acid profiles [with majority being C19 : 0 cyclo ω8c and summed feature 8 (C18 : 1ω7c/C18 : 1ω6c)], DNA G+C content (57.6 mol%), and carbon compound utilization patterns supported the placement of the novel strains in the genus Rhizobium. Results of average nucleotide identity (ANI) differentiated the novel strains from the closest species of the genus Rhizobium, R. mesoamericanum, R. grahamii and R. tibeticum with 89.0, 88.1 and 87.8 % similarity, respectively. The symbiotic genes essential for nodulation (nodC) and nitrogen fixation (nifH) were most similar (99-100 %) to those of R. mesoamericanum, another Mimosa-nodulating species. Based on the current data, these 10 strains represent a novel species of the genus Rhizobium for which the name Rhizobium altiplani sp. nov. is proposed. The type strain is BR 10423T (=HAMBI 3664T).

  2. Pyruvate Dehydrogenase and Pyruvate Dehydrogenase Kinase Expression in Non Small Cell Lung Cancer and Tumor-Associated Stroma

    Directory of Open Access Journals (Sweden)

    Michael I. Koukourakis

    2005-01-01

    Full Text Available Pyruvate dehydrogenase (PDH catalyzes the conversion of pyruvate to acetyl-coenzyme A, which enters into the Krebs cycle, providing adenosine triphosphate (ATP to the cell. PDH activity is under the control of pyruvate dehydrogenase kinases (PDKs. Under hypoxic conditions, conversion of pyruvate to lactate occurs, a reaction catalyzed by lactate dehydrogenase 5 (LDH5. In cancer cells, however, pyruvate is transformed to lactate occurs, regardless of the presence of oxygen (aerobic glycolysis/Warburg effect. Although hypoxic intratumoral conditions account for HIFia stabilization and induction of anaerobic metabolism, recent data suggest that high pyruvate concentrations also result in HIFia stabilization independently of hypoxia. In the present immunohistochemical study, we provide evidence that the PDH/PDK pathway is repressed in 73% of non small cell lung carcinomas, which may be a key reason for HIFia stabilization and “aerobic glycolysis.” However, about half of PDHdeficient carcinomas are not able to switch on the HIF pathway, and patients harboring these tumors have an excellent postoperative outcome. A small subgroup of clinically aggressive tumors maintains a coherent PDH and HIF/LDH5 expression. In contrast to cancer cells, fibroblasts in the tumor-supporting stroma exhibit an intense PDH but reduced PDK1 expression favoring maximum PDH activity. This means that stroma may use lactic acid produced by tumor cells, preventing the creation of an intolerable intratumoral acidic environment at the same time.

  3. First case report of sepsis caused by Rhizobium pusense in Japan.

    Science.gov (United States)

    Kuchibiro, Tomokazu; Hirayama, Katsuhisa; Houdai, Katsuyuki; Nakamura, Tatsuya; Ohnuma, Kenichirou; Tomida, Junko; Kawamura, Yoshiaki

    2018-01-01

    Species of the genus Rhizobium are opportunistic, usually saprophytic, glucose-non-fermenting, Gram-negative bacilli found in agricultural soil. Rhizobium pusense infections are the least common Rhizobium infections and have low incidence. Herein, we report the first case of sepsis with R. pusense in Japan in a 67-year-old Japanese woman with a history of hyperlipidaemia, hypertension, diabetes, hypothyroidism and osteoporosis. She had undergone cerebrovascular treatment because she was diagnosed with a subarachnoid haemorrhage. The results of postoperative blood culture showed oxidase-positive, urease-positive, non-lactose-fermenting Gram-stain-negative rods. Using the Vitek2 system, the isolate was distinctly identified as Rhizobium radiobacter . However, 16S rRNA gene sequencing showed 99.93 % similarity with the type strain of R. pusense and 99.06 % similarity with the type strain of R. radiobacter . Additional gene sequencing analysis using recA (97.2 %) and atpD (96.2 %) also showed that the isolated strain is most closely related to R. pusense . The patient was cured by treatment using intravenous meropenem (3 g/d) for 4 weeks and was discharged safely. The definite source of sepsis was unknown. However, the possibility of having been infected through the catheter during the cerebrovascular operation was speculated.

  4. Competitive Advantage Provided by Bacterial Motility in the Formation of Nodules by Rhizobium meliloti

    Science.gov (United States)

    Ames, Peter; Bergman, Kostia

    1981-01-01

    The effect of motility on the competitive success of Rhizobium meliloti in nodule production was investigated. A motile strain formed more nodules than expected when mixed at various unfavorable ratios with either flagellated or nonflagellated nonmotile derivatives. We conclude that motility confers a selective advantage on rhizobia when competing with nonmotile strains. PMID:7298580

  5. Populasi Bakteri Rhizobium di Tanah pada beberapa Tanaman dari Pulau Buton, Kabupaten Muna, Propinsi Sulawesi Tenggara

    Directory of Open Access Journals (Sweden)

    Sri Purwaningsih

    2009-01-01

    Full Text Available The research was conducted in order to know population of Rhizobium bacteria in the soil at several plant from Buton island, Muna regency, Southeast Sulawesi. The purpose of the study was to get the population data and pure cultures of Rhizobium bacteria. Rhizobium bacteria were isolated from 13 sample from rhizosphere of fruit plant, 14 sample soil from rhizosphere of yield plant, 5 sample soil from rhizosphere of horticulture plant, and 8 samples soil was from forest plant. Isolation was conducted in standard medium of Yeast Extract Mannitol Agar (YEMA, the inoculation at (27-280C, and the population was counted by plate count methods. The growth characteristic of strain was observed by using YEMA medium mixed respectively with Brom Thymol Blue and Congo Red as an indicators. The population of Rhizobium bacteria was in the range of 7-115 × 105 CFU g-1 soil, and the highest population was found from the sample soil from rhizosphere with Ipomea batatas plant. Forty nine gave of pure culture, thirty five isolates can be grouped as fast growing, while fourteen can be grouped as slow growing.

  6. Visualization of Nodulation Gene Activity on the Early Stages of Rhizobium leguminosarum bv. viciae Symbiosis

    Czech Academy of Sciences Publication Activity Database

    Chovanec, Pavel; Novák, Karel

    2005-01-01

    Roč. 50, č. 4 (2005), s. 323-331 ISSN 0015-5632 R&D Projects: GA ČR GA521/03/0192 Institutional research plan: CEZ:AV0Z50200510 Keywords : nodulation * rhizobium leguminosarum * vicia tetrasperma Subject RIV: EE - Microbiology, Virology Impact factor: 0.918, year: 2005

  7. Effect of combined inoculations of Rhizobium-Arbuscular Mycorrhiza in Leucaena leucocephala CV: Perú

    Directory of Open Access Journals (Sweden)

    Lázaro Jesús Ojeda Quintana

    2014-07-01

    Full Text Available The work was conducted at the Experimental Station of Soil and Fertilizer “Escambray” land of farmers and associated rural extension. The experimental design was randomized blocks, and treatments: Rizhobium loti V-4033 (Research Institute of Pastures and Forages, mycorrhizal fungi trainers, Rhizobium +mycorrhiza fungi trainers, nitrogen and total control. Inoculation with my corrhiza forming fungi was performed at 10 g/bag Certificate MicoFert Strain the Institute of Ecology and Systematics-3: Glomus spurcum, Topes de Collantes, 85 % colonization of rootlets, while the Rhizobium was inoculated in a dose of 50 g/kg of seed. Variant was nitrogen at 25 kg/ha of urea. The plots occupied 18m2 , with an area of 9 m2 evaluable. When the plants reached 7.5 months and an average height of 143.4 cm proceeded to make the Court of establishment and then four foliage cuts were made every 90 days. Each cut dry biomass yield, and phosphorus content was determined crude protein. The combined inoculation of Rhizobium and mycorrhiza fungi Makers increased the yield of dry biomass, and phosphorus content of crude protein. We conclude proposing the adoption of an alternative methodology using mycorrhiza formers Fungi and Rhizobium in Leucaena leucocephala as a way to increase the yield of dry biomass, decreasing mineral fertilization and contribute to environmental protection

  8. Cultivar and Rhizobium Strain Effects on the Symbiotic Performance of Pea (Pisum sativum)

    DEFF Research Database (Denmark)

    Skøt, Leif

    1983-01-01

    The symbiotic performance of four pea (Pisum sativum L.) cultivars in combination with each of four strains of Rhizobium leguminosarum was studied in growth chamber experiments in order to estimate the effects of cultivars, strains and cultivar × strain interaction on the variation in dry weight, N...

  9. The symbiosis between Rhizobium leguminosarum and Pisum sativum : regulation of the nitrogenase activity

    NARCIS (Netherlands)

    Appels, M.A.

    1989-01-01

    Bacteria of the genus Rhizobium can form a symbiosis with plants of the family Leguminosae. Both bacteria and plant show considerable biochemical and morphological changes in order to develop and carry out the symbiosis. The Rhizobia

  10. Rhizoplane colonisation of peas by Rhizobium leguminosarum bv. viceae and a deleterious Pseudomonas putida

    NARCIS (Netherlands)

    Berggren, I.; Alstrom, S.; Vuurde, van J.W.L.; Martensson, A.M.

    2005-01-01

    Pseudomonas putida strain angstrom 313, a deleterious rhizosphere bacterium, reduced pea nitrogen content when inoculated alone or in combination with Rhizobium leguminosarum bv. viceae on plants in the presence of soil under greenhouse conditions. When plants were grown gnotobiotically in liquid

  11. Biodegradation pathway of L-glutamatediacetate by Rhizobium radiobacter strain BG-1

    NARCIS (Netherlands)

    Ginkel, van C.G.; Geerts, R.; Nguyen, P.D.; Plugge, C.M.

    2008-01-01

    An aerobic bacterium was isolated from activated sludge in a medium containing l-glutamate-N,N-diacetate (l-GLDA) as sole carbon and energy source. The isolate was identified as a Rhizobium radiobacter species. Besides l-GLDA, the strain utilized nitrilotriacetate (NTA) and proposed intermediates in

  12. Energy supply for dinitrogen fixation by Azotobacter vinelandii and by bacteroids of Rhizobium leguminosarum

    NARCIS (Netherlands)

    Laane, N.C.M.

    1980-01-01

    The central issue of this thesis is how obligate aerobes, such as Rhizobium leguminosarum bacteroids and Azotobacter vinelandii, generate and regulate the energy supply (in the form of ATP and reducing equivalents) for nitrogenase.
    In an effective

  13. Effects of Rhizobium inoculation on Trifolium resupinatum antioxidant system under sulfur dioxide pollution

    Directory of Open Access Journals (Sweden)

    Ladan Bayat

    2014-01-01

    Full Text Available Introduction: Plant growth stimulating rhizobacteria are beneficial bacteria that can cause resistance to various stresses in plants. One of these stresses is SO2 air pollution. SO2 is known as a strong damaging air pollutant that limits growth of plants. The aim of this study is evaluation of the effects of bacterial inoculation with native and standard Rhizobium on Persian clover root growth and antioxidants activity and capacity under air SO2 pollution. Materials and methods: In this study, 31 days plants (no-inoculated and inoculated with two strains of Rhizobium exposed to the different concentrations of SO2 (0 as a control, 0.5, 1, 1.5 and 2 ppm for 5 consecutive days and 2 hours per day. Results: Results showed different concentrations of SO2 had a significant effect on Persian clover root weight and antioxidant system. Increasing SO2 stress decreased root fresh and dry weight and antioxidant capacities (IC50 and increased antioxidant activities (I% of Persian clover leaves significantly in comparison to the control plants (under 0 ppm and increased SOD, CAT and GPX activity. Inoculation of Persian clover plants with native and standard Rhizobium increased root weight and did not show a significant effect on antioxidants activity and capacity, but interaction between Rhizobium inoculation and SO2 treatment reduced significantly the stress effects of high concentration of SO2 on root growth and antioxidants activity and capacity. In fact, level of this change of root growth and antioxidant system under SO2 pollution stress in inoculated plants was lower than in the non-inoculated plants. Discussion and conclusion: As a result, an increase in SO2 concentration caused a decrease in root weight, increase in antioxidants activity and capacity of Persian clover. Inoculation with Rhizobium strains could alleviate the effect of SO2 pollution on antioxidant system by effects on root growth.

  14. Carbohydrate metabolism during prolonged exercise and recovery: interactions between pyruvate dehydrogenase, fatty acids, and amino acids

    DEFF Research Database (Denmark)

    Mourtzakis, Marina; Saltin, B.; Graham, T.

    2006-01-01

    During prolonged exercise, carbohydrate oxidation may result from decreased pyruvate production and increased fatty acid supply and ultimately lead to reduced pyruvate dehydrogenase (PDH) activity. Pyruvate also interacts with the amino acids alanine, glutamine, and glutamate, whereby the decline...... amino acid taken up during exercise and recovery. Alanine and glutamine were also associated...... with pyruvate metabolism, and they comprised 68% of total amino-acid release during exercise and recovery. Thus reduced pyruvate production was primarily associated with reduced carbohydrate oxidation, whereas the greatest production of pyruvate was related to glutamate, glutamine, and alanine metabolism...

  15. Ethyl Pyruvate Emerges as a Safe and Fast Acting Agent against Trypanosoma brucei by Targeting Pyruvate Kinase Activity.

    Directory of Open Access Journals (Sweden)

    Netsanet Worku

    Full Text Available Human African Trypanosomiasis (HAT also called sleeping sickness is an infectious disease in humans caused by an extracellular protozoan parasite. The disease, if left untreated, results in 100% mortality. Currently available drugs are full of severe drawbacks and fail to escape the fast development of trypanosoma resistance. Due to similarities in cell metabolism between cancerous tumors and trypanosoma cells, some of the current registered drugs against HAT have also been tested in cancer chemotherapy. Here we demonstrate for the first time that the simple ester, ethyl pyruvate, comprises such properties.The current study covers the efficacy and corresponding target evaluation of ethyl pyruvate on T. brucei cell lines using a combination of biochemical techniques including cell proliferation assays, enzyme kinetics, phasecontrast microscopic video imaging and ex vivo toxicity tests. We have shown that ethyl pyruvate effectively kills trypanosomes most probably by net ATP depletion through inhibition of pyruvate kinase (Ki = 3.0±0.29 mM. The potential of ethyl pyruvate as a trypanocidal compound is also strengthened by its fast acting property, killing cells within three hours post exposure. This has been demonstrated using video imaging of live cells as well as concentration and time dependency experiments. Most importantly, ethyl pyruvate produces minimal side effects in human red cells and is known to easily cross the blood-brain-barrier. This makes it a promising candidate for effective treatment of the two clinical stages of sleeping sickness. Trypanosome drug-resistance tests indicate irreversible cell death and a low incidence of resistance development under experimental conditions.Our results present ethyl pyruvate as a safe and fast acting trypanocidal compound and show that it inhibits the enzyme pyruvate kinase. Competitive inhibition of this enzyme was found to cause ATP depletion and cell death. Due to its ability to easily cross

  16. Anaplerotic roles of pyruvate carboxylase in mammalian tissues.

    Science.gov (United States)

    Jitrapakdee, S; Vidal-Puig, A; Wallace, J C

    2006-04-01

    Pyruvate carboxylase (PC) catalyzes the ATP-dependent carboxylation of pyruvate to oxaloacetate. PC serves an anaplerotic role for the tricarboxylic acid cycle, when intermediates are removed for different biosynthetic purposes. In liver and kidney, PC provides oxaloacetate for gluconeogenesis. In adipocytes PC is involved in de novo fatty acid synthesis and glyceroneogenesis, and is regulated by the peroxisome proliferator-activated receptor-gamma, suggesting that PC is involved in the metabolic switch controlling fuel partitioning toward lipogenesis. In islets, PC is necessary for glucose-induced insulin secretion by providing oxaloacetate to form malate that participates in the 'pyruvate/malate cycle' to shuttle 3C or 4C between mitochondria and cytoplasm. Hyperglycemia and hyperlipidemia impair this cycle and affect glucose-stimulated insulin release. In astrocytes, PC is important for de novo synthesis of glutamate, an important excitatory neurotransmitter supplied to neurons. Transcriptional studies of the PC gene pinpoint some transcription factors that determine tissue-specific expression.

  17. Exogenous pyruvate facilitates cancer cell adaptation to hypoxia by serving as an oxygen surrogate.

    Science.gov (United States)

    Yin, Chengqian; He, Dan; Chen, Shuyang; Tan, Xiaoling; Sang, Nianli

    2016-07-26

    Molecular oxygen is the final electron acceptor in cellular metabolism but cancer cells often become adaptive to hypoxia, which promotes resistance to chemotherapy and radiation. The reduction of endogenous glycolytic pyruvate to lactate is known as an adaptive strategy for hypoxic cells. Whether exogenous pyruvate is required for hypoxic cell proliferation by either serving as an electron acceptor or a biosynthetic substrate remains unclear. By using both hypoxic and ρ0 cells defective in electron transfer chain, we show that exogenous pyruvate is required to sustain proliferation of both cancer and non-cancer cells that cannot utilize oxygen. Particularly, we show that absence of pyruvate led to glycolysis inhibition and AMPK activation along with decreased NAD+ levels in ρ0 cells; and exogenous pyruvate increases lactate yield, elevates NAD+/NADH ratio and suppresses AMPK activation. Knockdown of lactate dehydrogenase significantly inhibits the rescuing effects of exogenous pyruvate. In contrast, none of pyruvate-derived metabolites tested (including acetyl-CoA, α-ketoglutarate, succinate and alanine) can replace pyruvate in supporting ρ0 cell proliferation. Knockdown of pyruvate carboxylase, pyruvate dehydrogenase and citrate synthase do not impair exogenous pyruvate to rescue ρ0 cells. Importantly, we show that exogenous pyruvate relieves ATP insufficiency and mTOR inhibition and promotes proliferation of hypoxic cells, and that well-oxygenated cells release pyruvate, providing a potential in vivo source of pyruvate. Taken together, our data support a novel pyruvate cycle model in which oxygenated cells release pyruvate for hypoxic cells as an oxygen surrogate. The pyruvate cycle may be targeted as a new therapy of hypoxic cancers.

  18. Pyruvate decarboxylases from the petite-negative yeast Saccharomyces kluyveri

    DEFF Research Database (Denmark)

    Møller, Kasper; Langkjær, Rikke Breinhold; Nielsen, Jens

    2004-01-01

    was controlled by variations in the amount of mRNA. The mRNA level and the pyruvate decarboxylase activity responded to anaerobiosis and growth on different carbon sources in essentially the same fashion as in S. cerevisiae. This indicates that the difference in ethanol formation between these two yeasts...... is not due to differences in the regulation of pyruvate decarboxylase(s), but rather to differences in the regulation of the TCA cycle and the respiratory machinery. However, the PDC genes of Saccharomyces/Kluyveromyces yeasts differ in their genetic organization and phylogenetic origin. While S. cerevisiae...

  19. Transformation of pWWO in Rhizobium leguminosarum DPT to Engineer Toluene Degrading Ability for Rhizoremediation

    OpenAIRE

    Goel, Garima; Pandey, Piyush; Sood, Anchal; Bisht, Sandeep; Maheshwari, D. K.; Sharma, G. D.

    2011-01-01

    Rhizoremediation of organic xenobiotics is based on interactions between plants and their associated micro-organisms. The present work was designed to engineer a bacterial system having toluene degradation ability along with plant growth promoting characteristics for effective rhizoremediation. pWWO harboring the genes responsible for toluene breakdown was isolated from Pseudomonas putida MTCC 979 and successfully transformed in Rhizobium DPT. This resulted in a bacterial strain (DPTT) which ...

  20. Novel mutations associated with pyruvate kinase deficiency in Brazil

    Directory of Open Access Journals (Sweden)

    Maria Carolina Costa Melo Svidnicki

    2018-01-01

    Full Text Available Background: Pyruvate kinase deficiency is a hereditary disease that affects the glycolytic pathway of the red blood cell, causing nonspherocytic hemolytic anemia. The disease is transmitted as an autosomal recessive trait and shows a marked variability in clinical expression. This study reports on the molecular characterization of ten Brazilian pyruvate kinase-deficient patients and the genotype–phenotype correlations. Method: Sanger sequencing and in silico analysis were carried out to identify and characterize the genetic mutations. A non-affected group of Brazilian individuals were also screened for the most commonly reported variants (c.1456C>T and c.1529G>A. Results: Ten different variants were identified in the PKLR gene, of which three are reported here for the first time: p.Leu61Gln, p.Ala137Val and p.Ala428Thr. All the three missense variants involve conserved amino acids, providing a rationale for the observed enzyme deficiency. The allelic frequency of c.1456C>T was 0.1% and the 1529G>A variant was not found. Conclusion: This is the first comprehensive report on molecular characterization of pyruvate kinase deficiency from South America. The results allowed us to correlate the severity of the clinical phenotype with the identified variants. Keywords: Red cell disorder, Pyruvate kinase, Mutation, Hemolytic anemia, PKLR gene

  1. Characterization of a C 4 maize pyruvate orthophosphate dikinase ...

    African Journals Online (AJOL)

    Pyruvate orthophosphate dikinase (PPDK) is a key enzyme in plants that utilize the C4 photosynthetic pathway to fix CO2. The enzymatic reaction catalyzed by PPDK is critically controlled by light and is one of the rate-limiting steps of the C4 pathway. The intact maize (Zea mays) C4-PPDK gene, containing its own promoter, ...

  2. DEVELOPMENT OF PIGEON PEA INOCULATED WITH RHIZOBIUM ISOLATED FROM COWPEA TRAP HOST PLANTS

    Directory of Open Access Journals (Sweden)

    SALOMÃO LIMA GUIMARÃES

    2016-01-01

    Full Text Available Pigeon pea is an important protein source grown in several tropical and sub - tropical countries, and is considered a multi - purpose plant that is resistant to the conditions of the Brazilian Cerrado. Among the possible uses for cowpea, its use as a green manure, increasing soil nitrogen content through the association with diazotrophic bacteria, generically known as rhizobia, is noteworthy. The present work aimed to evaluate the efficiency of Rhizobium strains isolated from cowpea plants in the development of pigeon peas cultured in Red Latosol. The experiment was conducted in a greenhouse, using a completely randomized design with seven treatments and four replications. Treatments consisted of inoculation with four Rhizobium strains (MT8, MT15, MT16, and MT23 and one commercial inoculant comprising Bradyrhizobium spp. strains BR 2801 and BR 2003. There were two controls, one absolute (without inoculation or nitrogen fertilization and the other with nitrogen fertilization. Each experimental plot consisted of an 8 - dm 3 vase containing three plants. Analyzed variables included plant height, SPAD index, number and dry weight of nodules, and shoot and root dry masses. Pigeon peas responded significantly to inoculation treatment, since all the plants inoculated with Rhizobium strains isolated from cowpea strains showed results similar to plants in the nitrogen control and commercial inoculant treatments. This demonstrates a favorable plant – bacteria interaction, which can be utilized as an alternative nitrogen source for pigeon peas.

  3. NPR1 protein regulates pathogenic and symbiotic interactions between Rhizobium and legumes and non-legumes.

    Directory of Open Access Journals (Sweden)

    Smadar Peleg-Grossman

    Full Text Available BACKGROUND: Legumes are unique in their ability to establish symbiotic interaction with rhizobacteria from Rhizobium genus, which provide them with available nitrogen. Nodulation factors (NFs produced by Rhizobium initiate legume root hair deformation and curling that entrap the bacteria, and allow it to grow inside the plant. In contrast, legumes and non-legumes activate defense responses when inoculated with pathogenic bacteria. One major defense pathway is mediated by salicylic acid (SA. SA is sensed and transduced to downstream defense components by a redox-regulated protein called NPR1. METHODOLOGY/PRINCIPAL FINDINGS: We used Arabidopsis mutants in SA defense pathway to test the role of NPR1 in symbiotic interactions. Inoculation of Sinorhizobium meliloti or purified NF on Medicago truncatula or nim1/npr1 A. thaliana mutants induced root hair deformation and transcription of early and late nodulins. Application of S. meliloti or NF on M. truncatula or A. thaliana roots also induced a strong oxidative burst that lasted much longer than in plants inoculated with pathogenic or mutualistic bacteria. Transient overexpression of NPR1 in M. truncatula suppressed root hair curling, while inhibition of NPR1 expression by RNAi accelerated curling. CONCLUSIONS/SIGNIFICANCE: We show that, while NPR1 has a positive effect on pathogen resistance, it has a negative effect on symbiotic interactions, by inhibiting root hair deformation and nodulin expression. Our results also show that basic plant responses to Rhizobium inoculation are conserved in legumes and non-legumes.

  4. Co-inoculation with Glomus intraradices and Rhizobium tropici ...

    African Journals Online (AJOL)

    dell

    2012-07-19

    Jul 19, 2012 ... Beans play an important role in the enhancement of the level of nourishment ..... quantities of P to the plants from remote zones (Jansa et al., 2003). Also, the .... metabolic monitoring (NMR), and molecular analyses with in-situ ...

  5. Pré-seleção de estirpes de Rhizobium sp. para amendoim Preliminary selection of peanut Rhizobium sp. strains

    Directory of Open Access Journals (Sweden)

    Antonio Roberto Giardini

    1984-01-01

    Full Text Available Um ensaio foi conduzido em casa de vegetação, com solução nutritiva isenta de N, com o objetivo de selecionar estirpes de Rhizobium eficientes fixadoras de N2, quando associadas com amendoim (Arachis hypogaea L. cultivar Tatu. Foram testadas 35 estirpes de Rhizobium sp., isoladas de quinze diferentes espécies de leguminosas tropicais, e incluído um tratamento de inoculação com solo previamente cultivado com amendoim. Das 35 estirpes testadas, doze formaram nódulos e, entre essas, sete foram eficientes fixadoras de nitrogênio. Das doze estirpes que nodularam, sete foram isoladas de leguminosas da tribo Hedysareae (à qual pertence o género Arachis e, destas, apenas quatro foram eficientes fixadoras de nitrogênio. O peso e o número de nódulos não se mostraram como critérios adequados para avaliação da eficiência.An experiment was carried out in Leonard jars, in the greenhouse, with nitrogen-free nutrient solution to test the efficiency of 35 strains of rhizobia isolated from 15 species of tropical legumes. Twelve of the tested strains were capable of nodule formation in peanut. Seven of those strains were isolated from the trible Hedysareae, which includes the genus Arachis. Only four of the rhizobia strains with inducing nodulation were effective. Dry weight and number of nodules were not good criteria for evaluating effectiveness.

  6. Amperometric pyruvate sensor based on a pyruvate dehydrogenase-immobilized carbon paste electrode containing vitamin K3 as a mediator

    Energy Technology Data Exchange (ETDEWEB)

    Miki, K. [Nara National College of Technology, Nara (Japan); Kinoshita, H. [Kawassui Women`s College, Nagasaki (Japan); Yamamoto, Y. [Kyoto Municipal Junior College of Nursing, Kyoto (Japan); Taniguchi, N. [Kyoto Research Center for Hygiene, Kyoto (Japan); Ikeda, T. [Kyoto University, Kyoto (Japan). Faculty of Agriculture

    1995-12-05

    Pyruvate dehydrogenase (PDH) was immobilized on the surface of a carbon paste electrode containing vitamin K3 (2-Methyl-1,4-naphthoquinone, VK), and the electrode surface was covered with a dialysis membrane. The enzyme electrode produced an anodic current starting from -0.2 V to reach a limiting current at +0.1 V vs. Ag/AgCl due to the enzyme-catalyzed oxidation of pyruvate in a phosphate buffer solution of pH 7.0. The current response to pyruvate depended on the amounts of both the immobilized-PDH and VK mixed in the carbon paste electrode at low amount of the enzyme and VK, and became independent at above 0.15 mg PDH and 0.65% (w/w) VK. The electrode with 0.15mg PDH and 0.65% (w/w) VK could be used as a pyruvate sensor to measure in the range of 2 ,{mu}M to 3mM. The response time was about 60 sec, and the current was independent of pH in the range of 5.7 - 7.2. The presence of L-ascorbic acid didn`t interfere with this measurement. Phosphate ion could also be determined with this electrode in a citrate buffer solution. 14 refs., 6 figs., 1 tab.

  7. Comparative effectiveness of different Rhizobium sp. for improving growth and yield of maize (Zea mays L.

    Directory of Open Access Journals (Sweden)

    Ijaz Mehboob, Zahir Ahmad Zahir, Muhammad Arshad, Muhammad Khalid

    2012-05-01

    Full Text Available During the last couple of decades, it has been demonstrated that rhizobia can associate with roots of non-legumes also without forming true nodules, and can promote their growth by using one or more of the direct or indirect mechanisms of actions. This work examines the growth and yield responses of maize to inoculation with different species of rhizobia, isolated from the root nodules of chickpea (Cicer arietinum L., lentil (Lens culinaris M. and mung bean (Vigna radiata L. in pots and fields. Twenty isolates of rhizobia were isolated from root nodules each of mung bean, lentil and chickpea and were screened under axenic conditions. On the basis of their promising performance under axenic conditions, nine most efficient isolates (three from each legume host were selected, characterized and further evaluated for their growth promoting activities by conducting pot and field experiments. Results of pot experiment revealed that maximum increase in grain yield, 1000 grain weight, N, P and K uptake (up to 47.89, 54.52, 73.46, 84.66 and 59.19% by CRI28, respectively, over un-inoculated control was produced by the isolate of Mesorhizobium ciceri. Whereas, maximum improvement in rest of the parameters was caused by the isolates of Rhizobium phaseoli (i.e. fresh biomass, straw yield and root length up to 36.30% by A18, 25.46% by S6 and 81.89% by A18, respectively over un-inoculated control. Rhizobium leguminosarum isolates came out to be the least effective among the species tested. Similarly, all the selected isolates improved the growth and yield attributing parameters in fields as well but with varying capacity compared with un-inoculated control. The selected isolates of Mesorhizobium ciceri and Rhizobium phaseoli again remained superior compared to the isolates of Rhizobium leguminosarum under field conditions. The results of this study imply that rhizobium species had potential to promote growth and yield of maize but this technology should be

  8. Enzymatic synthesis of 11C-pyruvic acid and 11C-L-lactic acid

    International Nuclear Information System (INIS)

    Cohen, M.B.; Spolter, L.; Chang, C.C.; Cook, J.S.; Macdonald, N.S.

    1980-01-01

    L-Lactic acid is formed as the end product of glycolysis under anaerobic conditions in all cells, but this reaction is of special significance in the myocardium. L-Lactic acid is reversibly formed from and is in equilibrium with myocardial pyruvic acid, which is its sole metabolic pathway. 11 C-Pyruvic acid is synthesized from 11 C carbon dioxide using pyruvate-ferredoxin oxidoreductase and coenzymes. The 11 C-pyruvic acid is then converted to 11 -L-lactic acid by lactic acid dehydrogenase. The availability of 11 C-pyruvic acid and 11 C-L-lactic acid will permit the in vivo investigation of lactate metabolism. (author)

  9. Diversity of Rhizobium-Phaseolus vulgaris symbiosis: Overview and perspectives

    International Nuclear Information System (INIS)

    Martinez-Romero, Esperanza

    2001-01-01

    Common bean (Phaseolus vulgaris) has become a cosmopolitan crop, but was originally domesticated in the Americas and has been grown in Latin America for several thousand years. Consequently an enormous diversity of bean nodulating bacteria have developed and in the centers of origin the predominant species in bean nodules is R. etli. In some areas of Latin America, inoculation, which normally promotes nodulation and nitrogen fixation is hampered by the prevalence of native strains. Many other species in addition to R. etli have been found in bean nodules in regions where bean has been introduced. Some of these species such as R. leguminosarum bv. phaseoli, R. gallicum bv. phaseoli and R. giardinii bv. phaseoli might have arisen by acquiring the phaseoli plasmid from R. etli. Others, like R. trap id, are well adapted to acid soils and high temperatures and are good inoculants for bean under these conditions. The large number of rhizobia species capable of nodulating bean supports that bean is a promiscuous host and a diversity of bean-rhizobia interactions exists. Large ranges of dinitrogen fixing capabilities have been documented among bean cultivars and commercial beans have the lowest values among legume crops. Knowledge on bean symbiosis is still incipient but could help to improve bean biological nitrogen fixation. (author)

  10. Effects of salt and pH stress on temperature-tolerant Rhizobium sp. NBRI330 nodulating Prosopis juliflora.

    Science.gov (United States)

    Kulkarni, S; Nautiyal, C S

    2000-04-01

    A study was conducted to examine the growth response of a rhizobial strain Rhizobium sp. NBRI330 isolated from root nodules of Prosopis juliflora growing in alkaline soil. The strain had the ability to nodulate P. juliflora. Nursery grown plants inoculated with Rhizobium sp. NBRI330 had 60.6% higher plant dry weight, as compared with uninoculated plants. The individual stress survival limit of a rhizobial strain Rhizobium sp. NBRI330 isolated from alkaline soil in a medium containing 32% (wt/vol) salt was 8 h, and at 55 degrees C up to 3 h. The length of Rhizobium sp. NBRI330 in salt-stressed cells increased significantly to 3.04 microm from 1.75 microm of non-stressed control cells. On the contrary, the length of pH-stressed cells declined to 1.40 microm. Compared with non-stressed control rod-shaped cells, the shape of temperature-stressed cells changed to spherical, of 0.42 microm diameter. High temperature (45 degrees C) was tolerated efficiently by Rhizobium sp. NBRI330 in the presence of salt at pH 12, as compared with pH 7.

  11. Data regarding the growth of Lactobacillus acidophilus NCFM on different carbohydrates and recombinant production of elongation factor G and pyruvate kinase

    Directory of Open Access Journals (Sweden)

    Hasan Ufuk Celebioglu

    2017-10-01

    Full Text Available The present study describes the growth of the very well-known probiotic bacterium Lactobacillus acidophilus NCFM on different carbohydrates. Furthermore, recombinant production of putative moonlighting proteins elongation factor G and pyruvate kinase from this bacterium is described. For further and detailed interpretation of the data presented here, please see the research article “Mucin- and carbohydrate-stimulated adhesion and subproteome changes of the probiotic bacterium Lactobacillus acidophilus NCFM” (Celebioglu et al., 2017 [1].

  12. omega-Amino acid:pyruvate transaminase from Alcaligenes denitrificans Y2k-2: a new catalyst for kinetic resolution of beta-amino acids and amines.

    Science.gov (United States)

    Yun, Hyungdon; Lim, Seongyop; Cho, Byung-Kwan; Kim, Byung-Gee

    2004-04-01

    Alcaligenes denitrificans Y2k-2 was obtained by selective enrichment followed by screening from soil samples, which showed omega-amino acid:pyruvate transaminase activity, to kinetically resolve aliphatic beta-amino acid, and the corresponding structural gene (aptA) was cloned. The gene was functionally expressed in Escherichia coli BL21 by using an isopropyl-beta-D-thiogalactopyranoside (IPTG)-inducible pET expression system (9.6 U/mg), and the recombinant AptA was purified to show a specific activity of 77.2 U/mg for L-beta-amino-n-butyric acid (L-beta-ABA). The enzyme converts various beta-amino acids and amines to the corresponding beta-keto acids and ketones by using pyruvate as an amine acceptor. The apparent K(m) and V(max) for L-beta-ABA were 56 mM and 500 U/mg, respectively, in the presence of 10 mM pyruvate. In the presence of 10 mM L-beta-ABA, the apparent K(m) and V(max) for pyruvate were 11 mM and 370 U/mg, respectively. The enzyme exhibits high stereoselectivity (E > 80) in the kinetic resolution of 50 mM D,L-beta-ABA, producing optically pure D-beta-ABA (99% enantiomeric excess) with 53% conversion.

  13. ω-Amino Acid:Pyruvate Transaminase from Alcaligenes denitrificans Y2k-2: a New Catalyst for Kinetic Resolution of β-Amino Acids and Amines

    Science.gov (United States)

    Yun, Hyungdon; Lim, Seongyop; Cho, Byung-Kwan; Kim, Byung-Gee

    2004-01-01

    Alcaligenes denitrificans Y2k-2 was obtained by selective enrichment followed by screening from soil samples, which showed ω-amino acid:pyruvate transaminase activity, to kinetically resolve aliphatic β-amino acid, and the corresponding structural gene (aptA) was cloned. The gene was functionally expressed in Escherichia coli BL21 by using an isopropyl-β-d-thiogalactopyranoside (IPTG)-inducible pET expression system (9.6 U/mg), and the recombinant AptA was purified to show a specific activity of 77.2 U/mg for l-β-amino-n-butyric acid (l-β-ABA). The enzyme converts various β-amino acids and amines to the corresponding β-keto acids and ketones by using pyruvate as an amine acceptor. The apparent Km and Vmax for l-β-ABA were 56 mM and 500 U/mg, respectively, in the presence of 10 mM pyruvate. In the presence of 10 mM l-β-ABA, the apparent Km and Vmax for pyruvate were 11 mM and 370 U/mg, respectively. The enzyme exhibits high stereoselectivity (E > 80) in the kinetic resolution of 50 mM d,l-β-ABA, producing optically pure d-β-ABA (99% enantiomeric excess) with 53% conversion. PMID:15066855

  14. Increased superoxide accumulation in pyruvate dehydrogenase complex deficient fibroblasts.

    Science.gov (United States)

    Glushakova, Lyudmyla G; Judge, Sharon; Cruz, Alex; Pourang, Deena; Mathews, Clayton E; Stacpoole, Peter W

    2011-11-01

    The pyruvate dehydrogenase complex (PDC) oxidizes pyruvate to acetyl CoA and is critically important in maintaining normal cellular energy homeostasis. Loss-of-function mutations in PDC give rise to congenital lactic acidosis and to progressive cellular energy failure. However, the subsequent biochemical consequences of PDC deficiency that may contribute to the clinical manifestations of the disorder are poorly understood. We postulated that altered flux through PDC would disrupt mitochondrial electron transport, resulting in oxidative stress. Compared to cells from 4 healthy subjects, primary cultures of skin fibroblasts from 9 patients with variable mutations in the gene encoding the alpha subunit (E1α) of pyruvate dehydrogenase (PDA1) demonstrated reduced growth and viability. Superoxide (O(2)(.-)) from the Qo site of complex III of the electron transport chain accumulated in these cells and was associated with decreased activity of manganese superoxide dismutase. The expression of uncoupling protein 2 was also decreased in patient cells, but there were no significant changes in the expression of cellular markers of protein or DNA oxidative damage. The expression of hypoxia transcription factor 1 alpha (HIF1α) also increased in PDC deficient fibroblasts. We conclude that PDC deficiency is associated with an increase in O(2)(.-) accumulation coupled to a decrease in mechanisms responsible for its removal. Increased HIF1α expression may contribute to the increase in glycolytic flux and lactate production in PDC deficiency and, by trans-activating pyruvate dehydrogenase kinase, may further suppress residual PDC activity through phosphorylation of the E1α subunit. Copyright © 2011 Elsevier Inc. All rights reserved.

  15. Optic neuropathy in a patient with pyruvate dehydrogenase deficiency

    Energy Technology Data Exchange (ETDEWEB)

    Small, Juan E. [Massachusetts General Hospital and Harvard Medical School, Department of Radiology, Boston, MA (United States); Gonzalez, Guido E. [Massachusetts Eye and Ear Infirmary and Harvard Medical School, Department of Radiology, Boston, MA (United States); Clinica Alemana de Santiago, Departmento de Imagenes, Santiago (Chile); Nagao, Karina E.; Walton, David S. [Massachusetts Eye and Ear Infirmary and Harvard Medical School, Department of Ophthalmology, Boston, MA (United States); Caruso, Paul A. [Massachusetts Eye and Ear Infirmary and Harvard Medical School, Department of Radiology, Boston, MA (United States)

    2009-10-15

    Pyruvate dehydrogenase (PDH) deficiency is a genetic disorder of mitochondrial metabolism. The clinical manifestations range from severe neonatal lactic acidosis to chronic neurodegeneration. Optic neuropathy is an uncommon clinical sequela and the imaging findings of optic neuropathy in these patients have not previously been described. We present a patient with PDH deficiency with bilateral decreased vision in whom MRI demonstrated bilateral optic neuropathy and chiasmopathy. (orig.)

  16. Optic neuropathy in a patient with pyruvate dehydrogenase deficiency

    International Nuclear Information System (INIS)

    Small, Juan E.; Gonzalez, Guido E.; Nagao, Karina E.; Walton, David S.; Caruso, Paul A.

    2009-01-01

    Pyruvate dehydrogenase (PDH) deficiency is a genetic disorder of mitochondrial metabolism. The clinical manifestations range from severe neonatal lactic acidosis to chronic neurodegeneration. Optic neuropathy is an uncommon clinical sequela and the imaging findings of optic neuropathy in these patients have not previously been described. We present a patient with PDH deficiency with bilateral decreased vision in whom MRI demonstrated bilateral optic neuropathy and chiasmopathy. (orig.)

  17. Influence of a carbamate pesticide on growth, respiration (/sup 14/C)-carbon metabolism and symbiosis of a Rhizobium sp

    Energy Technology Data Exchange (ETDEWEB)

    Sekar, T; Balasubramanian, A [Tamil Nadu Agricultural Univ., Coimbatore (India)

    1979-04-01

    Addition of aldicarb (2 methyl-2(methyl thio) propionaldehyde-O-methyl carbamoyl oxime) in the growth medium enhanced the growth of Rhizobium sp. (cowpea group) at 2ppm level while an inhibition was observed at the normal (5 ppm) and higher (10 ppm) concentrations. Respiration of the cells was also inhibited by 5 and 10 ppm levels of the chemical eventhough a stimulation was observed at 2 ppm (lower) concentration. The insecticide, when incorporated at 5 and 10 ppm levels in the medium increased the /sup 14/C-glucose incorporation and considerably altered the assimilation of the radioactive carbon in different fractions of rhizobium cells. Soil application of this insecticide (Temik 10 G) reduced the number of nodules formed and the total nitrogen content in cowpea plants inoculated with the Rhizobium sp. but enhanced the dry matter production of cowpea plants.

  18. Inoculation of the nonlegume Capsicum annuum (L.) with Rhizobium strains. 1. Effect on bioactive compounds, antioxidant activity, and fruit ripeness.

    Science.gov (United States)

    Silva, Luís R; Azevedo, Jessica; Pereira, Maria J; Carro, Lorena; Velazquez, Encarna; Peix, Alvaro; Valentão, Patrícia; Andrade, Paula B

    2014-01-22

    Pepper (Capsicum annuum L.) is an economically important agricultural crop and an excellent dietary source of natural colors and antioxidant compounds. The levels of these compounds can vary according to agricultural practices, like inoculation with plant growth-promoting rhizobacteria. In this work we evaluated for the first time the effect of the inoculation of two Rhizobium strains on C. annuum metabolites and bioactivity. The results revealed a decrease of organic acids and no effect on phenolics and capsaicinoids of leaves from inoculated plants. In the fruits from inoculated plants organic acids and phenolic compounds decreased, showing that fruits from inoculated plants present a higher ripeness stage than those from uninoculated ones. In general, the inoculation with Rhizobium did not improve the antioxidant activity of pepper fruits and leaves. Considering the positive effect on fruit ripening, the inoculation of C. annuum with Rhizobium is a beneficious agricultural practice for this nonlegume.

  19. PDK4 Inhibits Cardiac Pyruvate Oxidation in Late Pregnancy.

    Science.gov (United States)

    Liu, Laura X; Rowe, Glenn C; Yang, Steven; Li, Jian; Damilano, Federico; Chan, Mun Chun; Lu, Wenyun; Jang, Cholsoon; Wada, Shogo; Morley, Michael; Hesse, Michael; Fleischmann, Bernd K; Rabinowitz, Joshua D; Das, Saumya; Rosenzweig, Anthony; Arany, Zoltan

    2017-12-08

    Pregnancy profoundly alters maternal physiology. The heart hypertrophies during pregnancy, but its metabolic adaptations, are not well understood. To determine the mechanisms underlying cardiac substrate use during pregnancy. We use here 13 C glucose, 13 C lactate, and 13 C fatty acid tracing analyses to show that hearts in late pregnant mice increase fatty acid uptake and oxidation into the tricarboxylic acid cycle, while reducing glucose and lactate oxidation. Mitochondrial quantity, morphology, and function do not seem altered. Insulin signaling seems intact, and the abundance and localization of the major fatty acid and glucose transporters, CD36 (cluster of differentiation 36) and GLUT4 (glucose transporter type 4), are also unchanged. Rather, we find that the pregnancy hormone progesterone induces PDK4 (pyruvate dehydrogenase kinase 4) in cardiomyocytes and that elevated PDK4 levels in late pregnancy lead to inhibition of PDH (pyruvate dehydrogenase) and pyruvate flux into the tricarboxylic acid cycle. Blocking PDK4 reverses the metabolic changes seen in hearts in late pregnancy. Taken together, these data indicate that the hormonal environment of late pregnancy promotes metabolic remodeling in the heart at the level of PDH, rather than at the level of insulin signaling. © 2017 American Heart Association, Inc.

  20. Cloning of affecting pyruvate decarboxylase gene in the production bioethanol of agricultural waste in the E.coli bacteria

    Directory of Open Access Journals (Sweden)

    Masome Zeinali

    2016-09-01

    Full Text Available Introduction: Ethanol made by a biomass is one of the useful strategies in terms of economic and environmental and as a clean and safe energy to replace fossil fuels considered and examined. Materials and methods: In this study, key enzyme in the production of ethanol (Pyruvate decarboxylase from Zymomonas mobilis bacteria was isolated and cloned at E. coli bacteria by freeze and thaw method. For gene cloning, we used specific primers of pdc and PCR reaction and then pdc gene isolated and pET 28a plasmid double digested with (Sal I and Xho I enzymes. Digestion Products were ligated by T4 DNA ligase in 16 °C for 16 hours. Results: Results of bacteria culture showed that a few colonies containing pET 28a plasmid could grow. Result of colony pcr of pdc gene with specific primers revealed 1700 bp bands in 1% agarose gel electrophoresis. The results of PCR with T7 promotor forward primer and pdc revers primer have proved the accurate direction of integration of pdc gene into plasmid and revealed 1885 bp band. Double digestion of recombinant plasmid with SalI and XhoI enzymes revealed same bands. Finally, RT showed the expected band of 1700 bp that implies the desired gene expression in the samples. Discussion and conclusion: Due to the increased production of ethanol via pyruvate decarboxylase gene cloning in expression plasmids with a strong promoter upstream of the cloning site can conclude that, pyruvate decarboxylase cloning as a key gene would be useful and according to beneficial properties of E. coli bacteria, transfering the gene to bacteria appears to be reasonable.

  1. Production of nodulation factors by Rhizobium meliloti: fermentation, purification and characterization of glycolipids.

    Science.gov (United States)

    Kohring, B; Baier, R; Niehaus, K; Pühler, A; Flaschel, E

    1997-12-01

    Lipooligosaccharides, synthesized by soil bacteria of the genera Rhizobium, are known to have multifunctional effects on a wide variety of plants as signal substances in symbiosis initiation, cell response elicitation and growth regulation. These so called nodulation (Nod-) factors represent interesting biotechnological products with respect to fundamental studies of symbiotic interactions as well as for potential applications. Therefore, a batch fermentation process on a scale of 30 l has been developed by means of the Rhizobium meliloti strain R.m. 1021 (pEK327) strongly overexpressing the genes for the synthesis of Nod factors. Induction by the flavone luteolin led to growth associated production of the lipooligosaccharides. Ultrafiltration was used for separating the biomass from the filtrate containing the extracellular Nod factors. Simultaneously, ultrafiltration reduced the amount of lipophilic substances, which would otherwise interfere with processes downstream. The second separation step consisted in adsorption on XAD-2, a nonspecific hydrophobic adsorptive resin. Adsorption of Nod factors was carried out by batch operation of a stirred tank. Desorption was performed by elution with methanol in a fixed bed column. A semi-preparative reversed phase HPLC (Polygoprep 100-30 C18) was chosen as the final purification step. The Nod factors were obtained after evaporation and lyophilization. Thus, about 600 mg of Nod factors were produced from 20 l of fermentation broth. The Nod factors produced by Rhizobium meliloti R.m. 1021 (pEK327) were identified by liquid secondary ion mass spectrometry and by reversed-phase HPLC as fluorescent derivatives of 2-aminobenzamide. The biological activity of the products was demonstrated by means of the root hair deformation (HAD-) assay.

  2. A Legume TOR Protein Kinase Regulates Rhizobium Symbiosis and Is Essential for Infection and Nodule Development.

    Science.gov (United States)

    Nanjareddy, Kalpana; Blanco, Lourdes; Arthikala, Manoj-Kumar; Alvarado-Affantranger, Xóchitl; Quinto, Carmen; Sánchez, Federico; Lara, Miguel

    2016-11-01

    The target of rapamycin (TOR) protein kinase regulates metabolism, growth, and life span in yeast, animals, and plants in coordination with nutrient status and environmental conditions. The nutrient-dependent nature of TOR functionality makes this kinase a putative regulator of symbiotic associations involving nutrient acquisition. However, TOR's role in these processes remains to be understood. Here, we uncovered the role of TOR during the bean (Phaseolus vulgaris)-Rhizobium tropici (Rhizobium) symbiotic interaction. TOR was expressed in all tested bean tissues, with higher transcript levels in the root meristems and senesced nodules. We showed TOR promoter expression along the progressing infection thread and in the infected cells of mature nodules. Posttranscriptional gene silencing of TOR using RNA interference (RNAi) showed that this gene is involved in lateral root elongation and root cell organization and also alters the density, size, and number of root hairs. The suppression of TOR transcripts also affected infection thread progression and associated cortical cell divisions, resulting in a drastic reduction of nodule numbers. TOR-RNAi resulted in reduced reactive oxygen species accumulation and altered CyclinD1 and CyclinD3 expression, which are crucial factors for infection thread progression and nodule organogenesis. Enhanced expression of TOR-regulated ATG genes in TOR-RNAi roots suggested that TOR plays a role in the recognition of Rhizobium as a symbiont. Together, these data suggest that TOR plays a vital role in the establishment of root nodule symbiosis in the common bean. © 2016 American Society of Plant Biologists. All Rights Reserved.

  3. Interacción micorriza vesiculo-arbuscular, Rhizobium leguminosa en un oxisol de los Llanos Orientales de Colombia

    Directory of Open Access Journals (Sweden)

    Satizabal E. Jorge H.

    1987-03-01

    Full Text Available En los dos primeros trabajos (la y lb, se evaluó la interacción entre cepas seleccionadas de Rhizobium (apropiadas para la leguminosa forrajera tropical Centrosema macrocarpum y especies (Entrophospora colombiana, Acaulospora longula, Glomus manihotis de micorriza vesiculo arbuscular (MVA, en un suelo esterilizado, fijador de P. Los experimentos se diferenciaron por las fuentes de P utilizadas. Por su mayor producción de materia seca, absorción de minerales, nodulación y infección por MVA, se destacaron las plantas inoculadas con cuales quiera de las cepas de FIlizobiumy Glomus manihotis (Experimento la o Acaulospora longula (Experimento lb. En la tercera investigación (Experimento II, se evalúo en Centrosema la interacción MVA, Rhizobiumo N-químico (niveles equivalentes a 0, 30,55, 105,0 + Rhiz. y 30 + Rhiz. kg N ha-1 y dosis de P (0, 20, 40 y 80 kg ha-1. Es aconsejable aplicar pequeñas dosis (30 kg ha-1 de N al momento de la siembra e inocular con Rhizobium. Plantas inoculadas con MVA presentaron su óptimo crecimiento con 40 kg P ha-1. Dosis de 80 kg P ha-1 favoreció la eficiencia de la bacteria más no la del hongo.In the first two works (la and lb we evaluated the interation between selected stumps of Rhizobium (appropiate for the tropical forage legumes Centrosema macrocarpum and species (Entrophospora colombiana, Acaulospora longula, Glomus manihotis of vesicular-arbuscular mycorrhiza (MVA, in a sterelize soil fixer of P. The two experiments are different because we used different P sources. For the best production of dry matter, absorption of minerals, nodulation and infection for MVA; rebounded the plants with the inoculation with any of the Rhizobium´s stumps and Glomus manihotis (Experiment la of Acaulospora longula (Experiment lb. In the third investigation (Experiment II we evaluated in Centrosema the interaction MVA. Rhizobium and chemical N (levels equivalent to 0,30. 55, 105, O + Rhizobium and 30 + Rhizobium kg N ha

  4. The roles of plant phenolics in defence and communication during Agrobacterium and Rhizobium infection.

    Science.gov (United States)

    Bhattacharya, Amita; Sood, Priyanka; Citovsky, Vitaly

    2010-09-01

    Phenolics are aromatic benzene ring compounds with one or more hydroxyl groups produced by plants mainly for protection against stress. The functions of phenolic compounds in plant physiology and interactions with biotic and abiotic environments are difficult to overestimate. Phenolics play important roles in plant development, particularly in lignin and pigment biosynthesis. They also provide structural integrity and scaffolding support to plants. Importantly, phenolic phytoalexins, secreted by wounded or otherwise perturbed plants, repel or kill many microorganisms, and some pathogens can counteract or nullify these defences or even subvert them to their own advantage. In this review, we discuss the roles of phenolics in the interactions of plants with Agrobacterium and Rhizobium.

  5. [Effect of indolylacetic acid on formation of bacteroid forms of Rhizobium leguminosarum].

    Science.gov (United States)

    Lobanok, E V; Bakanchikova, T I

    1979-01-01

    The purpose of this work was to study the effect of indolylacetic acid (IAA) on the strains of Rhizobium leguminosarum, effective and noneffective with respect to symbiotic nitrogen fixation (L4 and 245a, and 14--73, respectively). IAA at a concentration of 50 mcg/ml and higher inhibited the growth of the bacterium, temporarily delayed celular division, and induced intensive formation of elongated bacteroid-like cells, predominantly Y-shaped or having a clavate shape. Many bacteroid-like cells were capable of division after a certain delay.

  6. Catalytic-site mapping of pyruvate formate lyase. Hypophosphite reaction on the acetyl-enzyme intermediate affords carbon-phosphorus bond synthesis (1-hydroxyethylphosphonate).

    Science.gov (United States)

    Plaga, W; Frank, R; Knappe, J

    1988-12-15

    Pyruvate formate-lyase of Escherichia coli cells, a homodimeric protein of 2 x 85 kDa, is distinguished by the property of containing a stable organic free radical (g = 2.0037) in its resting state. The enzyme (E-SH) achieves pyruvate conversion to acetyl-CoA via two distinct half-reactions (E-SH + pyruvate in equilibrium E-S-acetyl + formate; E-S-acetyl + CoA in equilibrium E-SH + acetyl-CoA), the first of which has been proposed to involve reversible homolytic carbon-carbon bond cleavage [J. Knappe et al. (1984) Proc. Natl Acad. Sci. USA 81, 1332-1335]. Present studies identified Cys-419 as the covalent-catalytic cysteinyl residue via CNBr fragmentation of E-S-[14C]acetyl and radio-sequencing of the isolated peptide CB-Ac (amino acid residues 406-423). Reaction of the formate analogue hypophosphite with E-S-acetyl was investigated and found to produce 1-hydroxyethylphosphonate with a thioester linkage to the adjacent Cys-418. The structure was determined from the chymotryptic peptide CH-P (amino acid residues 415-425), using 31P-NMR spectroscopy (delta = 44 ppm) and by chemical characterisation through degradation into 1-hydroxyethylphosphonate with phosphodiesterase or bromine. This novel P-C-bond synthesis involves the enzyme-based free radical and is proposed to resemble the physiological C-C-bond synthesis (pyruvate production) from formate and E-S-acetyl. These findings are interpreted as proof of a radical mechanism for the action of pyruvate formate-lyase. The central Cys-418/Cys-419 pair of the active site shows a distinctive thiolate property even in the inactive (nonradical) form of the enzyme, as determined using an iodoacetate probe.

  7. Embryonic Lethality of Mitochondrial Pyruvate Carrier 1 Deficient Mouse Can Be Rescued by a Ketogenic Diet

    OpenAIRE

    Vanderperre, Beno?t; Herzig, S?bastien; Krznar, Petra; H?rl, Manuel; Ammar, Zeinab; Montessuit, Sylvie; Pierredon, Sandra; Zamboni, Nicola; Martinou, Jean-Claude

    2016-01-01

    Mitochondrial import of pyruvate by the mitochondrial pyruvate carrier (MPC) is a central step which links cytosolic and mitochondrial intermediary metabolism. To investigate the role of the MPC in mammalian physiology and development, we generated a mouse strain with complete loss of MPC1 expression. This resulted in embryonic lethality at around E13.5. Mouse embryonic fibroblasts (MEFs) derived from mutant mice displayed defective pyruvate-driven respiration as well as perturbed metabolic p...

  8. An ancestral role for the mitochondrial pyruvate carrier in glucose-stimulated insulin secretion

    OpenAIRE

    McCommis, Kyle S.; Hodges, Wesley T.; Bricker, Daniel K.; Wisidagama, Dona R.; Compan, Vincent; Remedi, Maria S.; Thummel, Carl S.; Finck, Brian N.

    2016-01-01

    Objective: Transport of pyruvate into the mitochondrial matrix by the Mitochondrial Pyruvate Carrier (MPC) is an important and rate-limiting step in its metabolism. In pancreatic β-cells, mitochondrial pyruvate metabolism is thought to be important for glucose sensing and glucose-stimulated insulin secretion. Methods: To evaluate the role that the MPC plays in maintaining systemic glucose homeostasis, we used genetically-engineered Drosophila and mice with loss of MPC activity in insulin-prod...

  9. The mitochondrial pyruvate carrier mediates high fat diet-induced increases in hepatic TCA cycle capacity

    OpenAIRE

    Rauckhorst, Adam J.; Gray, Lawrence R.; Sheldon, Ryan D.; Fu, Xiaorong; Pewa, Alvin D.; Feddersen, Charlotte R.; Dupuy, Adam J.; Gibson-Corley, Katherine N.; Cox, James E.; Burgess, Shawn C.; Taylor, Eric B.

    2017-01-01

    Objective: Excessive hepatic gluconeogenesis is a defining feature of type 2 diabetes (T2D). Most gluconeogenic flux is routed through mitochondria. The mitochondrial pyruvate carrier (MPC) transports pyruvate from the cytosol into the mitochondrial matrix, thereby gating pyruvate-driven gluconeogenesis. Disruption of the hepatocyte MPC attenuates hyperglycemia in mice during high fat diet (HFD)-induced obesity but exerts minimal effects on glycemia in normal chow diet (NCD)-fed conditions. T...

  10. Study on rhizobium interaction with osmoprotectant rhizobacteria for improving mung bean yield

    Science.gov (United States)

    Maryani, Y.; Sudadi; Dewi, W. S.; Yunus, A.

    2018-03-01

    Gunungkidul has calcareous soil with limitations including calcareous stone, mostly hilly terrain, and shallow cultivated layer. Furthermore, nowadays we face the disadvantages climates such as long dry seasons, a short rainy season and high temperatures caused by climate change. Climate change leads to irregular rainwater availability for microbes and crops. Research in this field is currently needed as climate change affected directly on crop production, while we need to find the strategy to keep high productivity of the plant. This research aimed to determine the ability of osmoprotectant rhizobacteria and rhizobium to support mung bean yield. Osmoprotectant rhizobacteria were isolated and screened from the calcareous soil in Gunungkidul with disadvantageous climates such as a long dry season, a short rainy season and high temperature. This research was arranged in Completely Randomized Design. The result showed that osmoprotectant rhizobacteria isolate of strain Al24-k and Ver5-k can produce 9.6306 mg g‑1 cell of glycine betaine in a soil density 1.7667 x 107 CFU g‑1 and 11.4870 mg g‑1 cell of glycine betaine in a soil density 1.9667 x 107 CFU g‑1. Inoculation of isolates osmoprotectant rhizobacteria can support mung bean yield. Osmoprotectant rhizobacteria isolate did not effect rhizobium in mung bean rhizosphere.

  11. Phenotypic and molecular characterization of Rhizobium vitis strains from vineyards in Turkey

    Directory of Open Access Journals (Sweden)

    Didem CANIK OREL

    2016-05-01

    Full Text Available Crown gall-affected grapevine samples were collected during 2009–2010 from major vineyards, located in different Turkish provinces. One hundred and three bacterial strains were obtained from 88 vineyards and 18 grapevine varieties; they were tumorigenic when inoculated in tobacco, sunflower and Datura stramonium plants and were identified as Rhizobium vitis using biochemical and physiological tests as well as PCR and specific primers. Nineteen R. vitis strains presented a number of anomalous biochemical and physiological characters. PCR and opine-specific primers revealed the presence of octopine/cucumopine-type plasmid in 82 R. vitis strains, nopaline-type plasmids in 18 strains and vitopine-type plasmids in three strains. Clonal relationship of strains was determined using Pulsed Field Gel Electrophoresis following digestion of genomic DNA with the restriction endonuclease PmeI. The greatest genetic diversity was found for the strains from Denizli, Ankara and Nevşehir provinces. Nopaline and vitopine-types of Rhizobium vitis were detected for the first time in Turkey.

  12. Transcriptomic characterization of soybean (Glycine max) roots in response to rhizobium infection by RNA sequencing

    International Nuclear Information System (INIS)

    He, Q.; Li, Z.; Wang, S.; Huang, S.; Yang, H.

    2018-01-01

    Legumes interacting with rhizobium to convert N2 into ammonia for plant use has attracted worldwide interest. However, the plant basal nitrogen fixation mechanisms induced in response to Rhizobium, giving differential gene expression of plants, have not yet been fully realized. The differential expressed genes of soybean between inoculated and mock-inoculated were analyzed by a RNA-Seq. The results of the sequencing were aligned against the Williams 82 genome sequence, which contain 55787 transcripts; 280 and 316 transcripts were found to be up- and down-regulated, respectively, for inoculated and mock-inoculated soybean roots at stage V1. Gene ontology (GO) analyses detected 104, 182 and 178 genes associated with the cell component category, molecular function category and biological process category, respectively. Pathway analysis revealed that 98 differentially expressed genes (115 transcripts) were involved in 169 biological pathways. We selected 19 differentially expressed genes and analyzed their expressions in mock-inoculated, inoculated USDA110 and CCBAU45436 using qRT-PCR. The results were in accordance with those obtained from rhizobia infected RNA-Seq data. These showed that the results of RNA-Seq had reliability and universality. Additionally, this study showed some novel genes associated with the nitrogen fixation process in comparison to previously identified QTLs. (author)

  13. Effectiveness and competing capacity of native Rhizobium strains evaluated in IX Region soils

    International Nuclear Information System (INIS)

    Barrientos D, Leticia; Mendez A, Edith; Pino N, Ines

    1995-01-01

    Symbiotic nitrogen fixation in legumes reaches its optimum when the host plants are nodulated by highly competitive and effective Rhizobium strains. With the purpose of assessing competition and nitrogen fixing capacity of native Rhizobium leguminosarum bio-var trifolii strains, a greenhouse test was carried out using white clover (Trifolium re-pens) and four kinds of soils, which represent the main agroecological areas of the IX Region. Eleven strains were evaluated, they were both native and collected and were streptomycin sulphate antibiotic resistant. A nitrogen and a nitrogen-less without inoculation testers were used as controls. All pots received a solution of ammonium sulphate marked with 10% 15 N a.e, equivalent to 10 kg ha -1 of N. Rye-grass was used as reference crop, cv. Nu-i. In general, the evaluated strains were very efficient. After three or four cuts they became the only source of nitrogen for the plants. They were also very competitive, getting to over 70% of root infection with regard to those present in soils. In Curacautin and Tolten soils, biological nitrogen fixation begins later than other soils evaluated, which is coincident with soils having a higher nitrogen content. Symbiosis occurs when the soil nitrogen content exhausts or diminishes. (author)

  14. Revegetating fly ash landfills with Prosopis juliflora L.: impact of different amendments and Rhizobium inoculation.

    Science.gov (United States)

    Rai, U N; Pandey, K; Sinha, S; Singh, A; Saxena, R; Gupta, D K

    2004-05-01

    A revegetation trial was conducted to evaluate the feasibility of growing a legume species, Prosopis juliflora L., on fly ash ameliorated with combination of various organic amendments, blue-green algal biofertilizer and Rhizobium inoculation. Significant enhancements in plant biomass, photosynthetic pigments, protein content and in vivo nitrate reductase activity were found in the plants grown on ameliorated fly ash in comparison to the plants growing in unamended fly ash or garden soil. Higher growth was obtained in fly ash amended with blue-green algae (BGA) than farmyard manure or press mud (PM), a waste from sugar-processing industry, due to the greater contribution of plant nutrients, supply of fixed nitrogen and increased availability of phosphorus. Nodulation was suppressed in different amendments of fly ash with soil in a concentration-duration-dependent manner, but not with other amendments. Plants accumulated higher amounts of Fe, Mn, Cu, Zn and Cr in various fly ash amendments than in garden soil. Further, inoculation of the plant with a fly ash tolerant Rhizobium strain conferred tolerance for the plant to grow under fly ash stress conditions with more translocation of metals to the above ground parts. The results showed the potential of P. juliflora to grow in plantations on fly ash landfills and to reduce the metal contents of fly ash by bioaccumulation in its tissues.

  15. The Effects of Seed Inoculation with Rhizobium and Nitrogen Application on Yield and some Agronomi Characterstics of Soybean (Glycine max L. under Ardabil Condition

    Directory of Open Access Journals (Sweden)

    M.N Seiedi

    2014-03-01

    Full Text Available In order to study the effects of seed inoculation with rhizobium and nitrogen application on yield and some agronomic characterstics of soybean (Glycine max L., a spilt plot experiment based on randomized complete block design with three replications was conducted in 2011 at the research farm of the Islamic Azad University, Ardabil Branch. Factors were inorganic nitrogen fertilizer urea at four levels (0, 30, 60 and 90 kg urea/ha in the main plot and two levels of inoculation with Rhizobium japanicum bacteria (with and without inoculation assigned to the sub plots. Study the growth indices showed that the maximum total dry matter (435.4 gr/m2 , crop growth rate (6.75 gr/m2.day and relative growth rate (0.1003 gr/gr.day were obtained from compound of treatments high levels of urea application × inoculation with rhizobium while, the minimum values of these indices recorded in without nitrogen application×non inoculation with rhizobium. The highest plant height, number of pod per plant and grain yield were obtained from the highest level of nitrogen fertilizer (90 kg/ha urea and seed inoculation with rhizobium. Number and dry weight of nodules per plant increased significantly with increasing nitrogen application till 60 kg/ha in seed inoculation with rhizobium. The lowest values of these traits recorded in non application of urea×non inoculation with rhizobium. Inoculation with rhizobium bacteria increased the number and dry weight of nodules per plant. Thus, it can be suggested that in order to increasing of grain yield, seed can be inoculated with rhizobium bacteria × application of 60 kg urea/ha in conditions of Ardabil region.

  16. Binding of ethyl pyruvate to bovine serum albumin: Calorimetric, spectroscopic and molecular docking studies

    Energy Technology Data Exchange (ETDEWEB)

    Pathak, Mallika [Department of Chemistry, Miranda House, University of Delhi, Delhi 11007 (India); Mishra, Rashmi; Agarwala, Paban K. [Department of Radiation Genetics and Epigenetics, Division of Radioprotective Drug Development Research, Institute of Nuclear Medicine and Allied Sciences, Delhi 110054 (India); Ojha, Himanshu, E-mail: himanshu.drdo@gmail.com [Department of Radiation Genetics and Epigenetics, Division of Radioprotective Drug Development Research, Institute of Nuclear Medicine and Allied Sciences, Delhi 110054 (India); Singh, Bhawna [Department of Radiation Genetics and Epigenetics, Division of Radioprotective Drug Development Research, Institute of Nuclear Medicine and Allied Sciences, Delhi 110054 (India); Singh, Anju; Kukreti, Shrikant [Nucleic Acid Research Laboratory, Department of Chemistry, University of Delhi, Delhi 11007 (India)

    2016-06-10

    Highlights: • ITC study showed binding of ethyl pyruvate with BSA with high binding affinity. • Ethyl pyruvate binding caused conformation alteration of BSA. • Fluorescence quenching mechanism is static in nature. • Electrostatic, hydrogen bonding and hydrophobic forces involved in binding. • Docking confirmed role of electrostatic, hydrogen bonding and hydrophobic forces. - Abstract: Various in vitro and in vivo studies have shown the anti-inflammatory and anticancer potential role of ethyl pyruvate. Bio-distribution of drugs is significantly influenced by the drug-serum protein binding. Therefore, the binding mechanism of the ethyl pyruvate with bovine serum albumin was investigated using UV–vis absorption, fluorescence, circular dichroism, isothermal titration calorimetry and molecular docking techniques. Absorption and fluorescence quenching studies indicated the binding of ethyl pyruvate with protein. Circular dichroism spectra of bovine serum albumin confirmed significant change in the conformation of protein upon binding. Thermodynamic data confirmed that ethyl pyruvate binds to bovine serum albumin at the two different sites with high affinity. Binding of ethyl pyruvate to bovine serum albumin involves hydrogen bonding, van der Waal and hydrophobic interactions. Further, docking studies indicated that ethyl pyruvate could bind significantly at the three binding sites. The results will definitely contribute to the development of ethyl pyruvate as drug.

  17. Pyruvate Dehydrogenase Kinase as a Novel Therapeutic Target in Oncology

    Directory of Open Access Journals (Sweden)

    Gopinath eSutendra

    2013-03-01

    Full Text Available Current drug development in oncology is non-selective as it typically focuses on pathways essential for the survival of all dividing cells. The unique metabolic profile of cancer, which is characterized by increased glycolysis and suppressed mitochondrial glucose oxidation provides cancer cells with a proliferative advantage, conducive with apoptosis resistance and even increased angiogenesis. Recent evidence suggests that targeting the cancer-specific metabolic and mitochondrial remodeling may offer selectivity in cancer treatment. Pyruvate dehydrogenase kinase (PDK is a mitochondrial enzyme that is activated in a variety of cancers and results in the selective inhibition of pyruvate dehydrogenase (PDH, a complex of enzymes that converts cytosolic pyruvate to mitochondrial acetyl-CoA, the substrate for the Krebs’ cycle. Inhibition of PDK with either small interfering RNAs or the orphan drug dichloroacetate (DCA shifts the metabolism of cancer cells from glycolysis to glucose oxidation and reverses the suppression of mitochondria-dependent apoptosis. In addition, this therapeutic strategy increases the production of diffusible Krebs’ cycle intermediates and mitochondria-derived reactive oxygen species (mROS, activating p53 or inhibiting pro-proliferative and pro-angiogenic transcription factors like nuclear factor of activated T-cells (NFAT and hypoxia-inducible factor 1α (HIF1α. These effects result in decreased tumor growth and angiogenesis in a variety of cancers with high selectivity. In a small but mechanistic clinical trial in patients with glioblastoma, a highly aggressive and vascular form of brain cancer, DCA decreased tumor angiogenesis and tumor growth, suggesting that metabolic targeting therapies can be translated directly to patients. Therefore, reversing the mitochondrial suppression with metabolic-modulating drugs, like PDK inhibitors holds promise in the rapidly expanding field of metabolic oncology.

  18. Pyruvate carboxylase deficiency: An underestimated cause of lactic acidosis

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    F. Habarou

    2015-03-01

    Full Text Available Pyruvate carboxylase (PC is a biotin-containing mitochondrial enzyme that catalyzes the conversion of pyruvate to oxaloacetate, thereby being involved in gluconeogenesis and in energy production through replenishment of the tricarboxylic acid (TCA cycle with oxaloacetate. PC deficiency is a very rare metabolic disorder. We report on a new patient affected by the moderate form (the American type A. Diagnosis was nearly fortuitous, resulting from the revision of an initial diagnosis of mitochondrial complex IV (C IV defect. The patient presented with severe lactic acidosis and pronounced ketonuria, associated with lethargy at age 23 months. Intellectual disability was noted at this time. Amino acids in plasma and organic acids in urine did not show patterns of interest for the diagnostic work-up. In skin fibroblasts PC showed no detectable activity whereas biotinidase activity was normal. We had previously reported another patient with the severe form of PC deficiency and we show that she also had secondary C IV deficiency in fibroblasts. Different anaplerotic treatments in vivo and in vitro were tested using fibroblasts of both patients with 2 different types of PC deficiency, type A (patient 1 and type B (patient 2. Neither clinical nor biological effects in vivo and in vitro were observed using citrate, aspartate, oxoglutarate and bezafibrate. In conclusion, this case report suggests that the moderate form of PC deficiency may be underdiagnosed and illustrates the challenges raised by energetic disorders in terms of diagnostic work-up and therapeutical strategy even in a moderate form.

  19. Pyruvate kinase M2: a potential target for regulating inflammation

    Directory of Open Access Journals (Sweden)

    Jose Carlos eAlves-Filho

    2016-04-01

    Full Text Available Pyruvate kinase (PK is the enzyme responsible for catalyzing the last step of glycolysis. Of the four PK isoforms expressed in mammalian cells, PKM2 has generated the most interest due to its impact on changes in cellular metabolism observed in cancer as well as in activated immune cells. As our understanding of dysregulated metabolism in cancer develops, and in light of the growing field of immunometabolism, intense efforts are in place to define the mechanism by which PKM2 regulates the metabolic profile of cancer as well as of immune cells. The enzymatic activity of PKM2 is heavily regulated by endogenous allosteric effectors as well as by intracellular signalling pathways, affecting both the enzymatic activity of PKM2 as a pyruvate kinase and the regulation of the recently described non-canonical nuclear functions of PKM2. We here review the current literature on PKM2 and its regulation, and discuss the potential for PKM2 as a therapeutic target in inflammatory and metabolic disorders.

  20. Directed evolution of pyruvate decarboxylase-negative Saccharomyces cerevisiae, yielding a C2-independent, glucose-tolerant, and pyruvate-hyperproducing yeast

    NARCIS (Netherlands)

    A.J. van Maris; J.M. Geertman; A. Vermeulen; M.K. Groothuizen; A.A. Winkler; M.D. Piper; J.P. van Dijken; J.T. Pronk

    2004-01-01

    textabstractThe absence of alcoholic fermentation makes pyruvate decarboxylase-negative (Pdc(-)) strains of Saccharomyces cerevisiae an interesting platform for further metabolic engineering of central metabolism. However, Pdc(-) S. cerevisiae strains have two growth defects:

  1. Field dependence of T1 for hyperpolarized [1-13C]pyruvate

    DEFF Research Database (Denmark)

    Chattergoon, N.; Martnez-Santiesteban, F.; Handler, W. B.

    2013-01-01

    conformation and properties of the dissolution media such as buffer composition, solution pH, temperature and magnetic field. We have measured the magnetic field dependence of the spin–lattice relaxation time of hyperpolarized [1-13C]pyruvate using field-cycled relaxometry. [1-13C]pyruvate was hyperpolarized...

  2. Relations between fatty acid synthesis, pyruvate concentration and cell concentration of suspensions of isolated rat hepatocytes

    NARCIS (Netherlands)

    Beynen, A.C.; Geelen, M.J.H.

    1984-01-01

    1. 1. The cell concentration of suspensions of isolated rat hepatocytes affects both the rate of pyruvate accumulation in the incubation medium and the rate of fatty acid synthesis. 2. 2. At low cell concentrations pyruvate accumulation is directly related to the cell concentration but levels off

  3. Apparent rate constant mapping using hyperpolarized [1-(13) C]pyruvate

    DEFF Research Database (Denmark)

    Khegai, O.; Schulte, R. F.; Janich, M. A.

    2014-01-01

    Hyperpolarization of [1-13C]pyruvate in solution allows real-time measurement of uptake and metabolism using MR spectroscopic methods. After injection and perfusion, pyruvate is taken up by the cells and enzymatically metabolized into downstream metabolites such as lactate, alanine, and bicarbona...

  4. A Patient With Pyruvate Carboxylase Deficiency and Nemaline Rods on Muscle Biopsy

    DEFF Research Database (Denmark)

    Unal, Ozlem; Orhan, Diclehan; Ostergaard, Elsebet

    2013-01-01

    Nemaline rods are the pathologic hallmark of nemaline myopathy, but they have also been described as a secondary phenomenon in a variety of other disorders. Nemaline rods have not been reported in pyruvate carboxylase deficiency before. Here we present a patient with pyruvate carboxylase deficiency...

  5. The moonlighting function of pyruvate carboxylase resides in the non-catalytic end of the TIM barrel.

    NARCIS (Netherlands)

    Huberts, D.H.; Venselaar, H.; Vriend, G.; Veenhuis, M.; Klei, I.J. van der

    2010-01-01

    Pyruvate carboxylase is a highly conserved enzyme that functions in replenishing the tricarboxylic acid cycle with oxaloacetate. In the yeast Hansenulapolymorpha, the pyruvate carboxylase protein is also required for import and assembly of the peroxisomal enzyme alcohol oxidase. This additional

  6. Detection of myocardial ischemia before infarction, based on accumulation of labeled pyruvate

    International Nuclear Information System (INIS)

    Goldstein, R.A.; Klein, M.S.; Sobel, B.E.

    1980-01-01

    To determine whether ischemic, but not irreversibly injured myocardium, can be differentiated from normal tissue based on accumulation of labeled pyruvate, isolated hearts were perfused with buffer containing [ 14 C]pyruvate under conditions of normal or low flow. Fifteen minutes after the hearts were exposed to labeled material, myocardial radioactivity was fourfold greater in ischemic compared to control hearts, due to accumulation of label in sequestered lactate produced from the pyruvate. Open-chest rabbits subjected to coronary occlusion exhibited a 1.73:1 ratio of radioactivity in ischemic compared with normal myocardium 15 min after systemic injection of [ 14 C]pyruvate. The results obtained suggest that zones of myocardial ischemia should be detectable in vivo by positron tomography after systemic administration of [ 11 C]pyruvate as well

  7. Synergy between Rhizobium phaseoli and Acidithiobacillus ferrooxidans in the Bioleaching Process of Copper

    Directory of Open Access Journals (Sweden)

    Xuecheng Zheng

    2016-01-01

    Full Text Available This study investigates the synergy of Rhizobium phaseoli and Acidithiobacillus ferrooxidans in the bioleaching process of copper. The results showed that additional R. phaseoli could increase leaching rate and cell number of A. ferrooxidans. When the initial cell number ratio between A. ferrooxidans and R. phaseoli was 2 : 1, A. ferrooxidans attained the highest final cell number of approximately 2 × 108 cells/mL and the highest copper leaching rate of 29%, which is 7% higher than that in the group with A. ferrooxidans only. R. phaseoli may use metabolized polysaccharides from A. ferrooxidans, and organic acids could chelate or precipitate harmful heavy metals to reduce their damage on A. ferrooxidans and promote its growth. Organic acids could also damage the mineral lattice to increase the leaching effect.

  8. Synergy between Rhizobium phaseoli and Acidithiobacillus ferrooxidans in the Bioleaching Process of Copper

    Science.gov (United States)

    Zheng, Xuecheng; Li, Dongwei

    2016-01-01

    This study investigates the synergy of Rhizobium phaseoli and Acidithiobacillus ferrooxidans in the bioleaching process of copper. The results showed that additional R. phaseoli could increase leaching rate and cell number of A. ferrooxidans. When the initial cell number ratio between A. ferrooxidans and R. phaseoli was 2 : 1, A. ferrooxidans attained the highest final cell number of approximately 2 × 108 cells/mL and the highest copper leaching rate of 29%, which is 7% higher than that in the group with A. ferrooxidans only. R. phaseoli may use metabolized polysaccharides from A. ferrooxidans, and organic acids could chelate or precipitate harmful heavy metals to reduce their damage on A. ferrooxidans and promote its growth. Organic acids could also damage the mineral lattice to increase the leaching effect. PMID:26942203

  9. Rhizobium laguerreae is the main nitrogen-fixing symbiont of cultivated lentil (Lens culinaris) in Morocco.

    Science.gov (United States)

    Taha, Kaoutar; Berraho, El Bekkay; El Attar, Imane; Dekkiche, Samia; Aurag, Jamal; Béna, Gilles

    2018-03-01

    Genetic diversity and population structure of 268 Lens culinaris symbiotic rhizobia collected from 40 cultivated fields in the main lentil production regions in Morocco were estimated. Three chromosomal housekeeping genes (recA, glnII and atpD) and one common symbiotic gene (nodC) were sequenced and analyzed in order to identify the local symbionts of lentil. The molecular phylogeny of the concatenated housekeeping genes clustered more than 95% of the isolates in one main clade together with Rhizobium laguerreae species. R. laguerreae represents the main symbiont of cultivated lentil in Morocco and, for the first time, a large sample of individuals is obtained for this species. There is a significant and high genetic differentiation of bacterial populations among the four regions for their symbiotic gene, and much lower for their housekeeping genes. The reasons why R. laguerreae is so frequently recovered in our study is discussed. Copyright © 2018 Elsevier GmbH. All rights reserved.

  10. Mekanisme Penambatan Nitrogen Udara oleh Bakteri Rhizobium Menginspirasi Perkembangan Teknologi Pemupukan Organik yang Ramah Lingkungan

    Directory of Open Access Journals (Sweden)

    GEDE MENAKA ADNYANA

    2014-01-01

    Full Text Available Interaction of microbes with human living in the nature are able to seen from their capabilitiesimproving the environmental by composting waste of agriculture to become organic fertilizer. In thecontrary, the epidemic and infectious phatogens are also its contribution. In agriculture sector, the livingof microbes has been explored to keep the soil fertile, and to improve growth and plant production.The symbiosis of Rhizobium bacteria with the specific host plant from legumes is able to run because ofboth side giving a signal, where host plant give an organic molecoles called inducer. From the bacteriaside, also give an organic materials called nod factor. The step of nitrogen fixation mechanism can bedescribed from infection of root legume as the first step, followed by the nitrogen fixation by thebacteroid and synthesis of the nitrogen organic by host plant as the last step. These natural processesinspire finding and development of the ecologically organic fertilizer technology.

  11. Potential of the Galega – Rhizobium galegae System for Bioremediation of Oil-Contaminated Soil

    Directory of Open Access Journals (Sweden)

    Minna M. Jussila

    2003-01-01

    Full Text Available Bioremediation potential of the nitrogen-fixing leguminous plant Galega orientalis Lam. and its microsymbiont Rhizobium galegae was evaluated in microcosm and mesocosm scale in oil and BTEX (benzene, toluene, ethylbenzene, xylene contaminated soils, with m-toluate serving as a model for the latter group. G. orientalis and Rhizobium galegae remained viable in m-toluate fractions up to 3000 ppm. Plant growth and nodulation were inhibited in 500 ppm m-toluate, but were restored when plants were transferred to clean medium. In soil, G. orientalis nodulated and showed good growth in 2000 ppm m-toluate as well as in diesel-contaminated soil in the field, where the plant was stimulating bacterial growth in the rhizosphere. A collection of 52 indigenous m-toluate-tolerating bacteria isolated from oil-contaminated rhizosphere of G. orientalis was characterised and identified by classical and molecular biological methods. 16SrDNA PCR-RFLP and (GTG5-PCR genomic fingerprinting combined with partial sequencing indicated the presence of five major lineages of the Bacteria domain. A TOL plasmid-specific xylE-PCR was developed in order to detect both active and potential degraders of m-toluate. The ability to degrade m-toluate in the presence of the gene xylE was detected only within the genus Pseudomonas. The isolates were tested for capacity to grow on m-toluate as their sole carbon and energy source. In laboratory experiments, the best rhizosphere isolates performed equally well to the positive control strain and are good candidates for inoculant production in the future. They have been tagged with marker genes for further studies on colonisation and persistence.

  12. Effect of chickpea in association with Rhizobium to crop productivity and soil fertility

    Directory of Open Access Journals (Sweden)

    Botir Khaitov

    2016-04-01

    Full Text Available The growth, development and yield of chickpea (Cicer ariеtinum L. is strongly influenced by abiotic factors such as salinity and drought in the arid conditions. The use of efficient plant growth promoting bacteria in chickpea production is the best solution to overcome those stresses. In the present study, 10 chickpea rhizobial strains were isolated and purified from the nodules of chickpea genotype grown on middle salinated soils with different chickpea cultivation histories, 3 of them were more efficient in salt tolerance and showed higher nodulation abilities. Local chickpea genotype Uzbekistan-32 was inoculated with selected Rhizobium bacterial strains before planting them to the field condition. Inoculation of plants with strains Rhizobium sp. R4, R6 and R9 significantly increased shoot, root dry matter, and nodule number by 17, 12, and 20% above the uninoculated plants, respectively. The shoot length increased by 52%, root length by 43%, shoot dry weight by 36%, and root dry weight by 64%. Inoculation significantly increased the pod number by 28% and yield up to 55% as compared to control plant. The effective indigenous rhizobial strains isolated in this study from chickpeas on middle salinated soils of Uzbekistan have the characters of broad host range, high nodulation efficiency, efficient N fixation, great salt tolerance. Soil nitrogen, phosphorus and carbon content of the soil at the end of experiments were positive in all the treatments compare control. In this study, we are focused with consideration of the relationship between chickpea and its symbiotic nitrogen-fixing root nodule bacterial strains and how it functions to influence plant productivity and soil fertility.

  13. Effect of Rhizobium inoculation of seeds and foliar fertilization on productivity of Pisum sativum L.

    Directory of Open Access Journals (Sweden)

    Tadeusz Zając

    2013-07-01

    Full Text Available Pea (Pisum sativum L. is the second most important grain legume crop in the world which has a wide array of uses for human food and fodder. One of the major factors that determines the use of field pea is the yield potential of cultivars. Presently, pre-sowing inoculation of pea seeds and foliar application of microelement fertilizers are prospective solutions and may be reasonable agrotechnical options. This research was undertaken because of the potentially high productivity of the 'afila' morphotype in good wheat complex soils. The aim of the study was to determine the effect of vaccination with Rhizobium and foliar micronutrient fertilization on yield of the afila pea variety. The research was based on a two-year (2009–2010 controlled field experiment, conducted in four replicates and carried out on the experimental field of the Bayer company located in Modzurów, Silesian region. experimental field soil was Umbrisol – slightly degraded chernozem, formed from loess. Nitragina inoculant, as a source of symbiotic bacteria, was applied before sowing seeds. Green area index (GAI of the canopy, photosynthetically active radiation (PAR, and normalized difference vegetation index (NDVI were determined at characteristic growth stages. The presented results of this study on symbiotic nitrogen fixation by leguminous plants show that the combined application of Nitragina and Photrel was the best combination for productivity. Remote measurements of the pea canopy indexes indicated the formation of the optimum leaf area which effectively used photosynthetically active radiation. The use of Nitragina as a donor of effective Rhizobium for pea plants resulted in slightly higher GAI values and the optimization of PAR and NDVI. It is not recommended to use foliar fertilizers or Nitragina separately due to the slowing of pea productivity.

  14. Effectiveness of halo-tolerant, auxin producing Pseudomonas and Rhizobium strains to improve osmotic stress tolerance in mung bean (Vigna radiata L.

    Directory of Open Access Journals (Sweden)

    Maqshoof Ahmad

    2013-12-01

    Full Text Available Halo-tolerant, auxin producing bacteria could be used to induce salt tolerance in plants. A number of Rhizobium and auxin producing rhizobacterial strains were assessed for their ability to tolerate salt stress by conducting osmoadaptation assay. The selected strains were further screened for their ability to induce osmotic stress tolerance in mung bean seedlings under salt-stressed axenic conditions in growth pouch/jar trials. Three most effective strains of Rhizobium and Pseudomonas containing ACC-deaminase were evaluated in combination, for their ability to induce osmotic stress tolerance in mung bean at original, 4, and 6 dS m-1 under axenic conditions. Results showed that sole inoculation of Rhizobium and Pseudomonas strains improved the total dry matter up to 1.4, and 1.9 fold, respectively, while the increase in salt tolerance index was improved up to 1.3 and 2.0 fold by the Rhizobium and Pseudomonas strains, respectively. However, up to 2.2 fold increase in total dry matter and salt tolerance index was observed due to combined inoculation of Rhizobium and Pseudomonas strains. So, combined application of Rhizobium and Pseudomonas strains could be explored as an effective strategy to induce osmotic stress tolerance in mung bean.

  15. An arsenate-reducing and alkane-metabolizing novel bacterium, Rhizobium arsenicireducens sp. nov., isolated from arsenic-rich groundwater.

    Science.gov (United States)

    Mohapatra, Balaram; Sarkar, Angana; Joshi, Swati; Chatterjee, Atrayee; Kazy, Sufia Khannam; Maiti, Mrinal Kumar; Satyanarayana, Tulasi; Sar, Pinaki

    2017-03-01

    A novel arsenic (As)-resistant, arsenate-respiring, alkane-metabolizing bacterium KAs 5-22 T , isolated from As-rich groundwater of West Bengal was characterized by physiological and genomic properties. Cells of strain KAs 5-22 T were Gram-stain-negative, rod-shaped, motile, and facultative anaerobic. Growth occurred at optimum of pH 6.0-7.0, temperature 30 °C. 16S rRNA gene affiliated the strain KAs 5-22 T to the genus Rhizobium showing maximum similarity (98.4 %) with the type strain of Rhizobium naphthalenivorans TSY03b T followed by (98.0 % similarity) Rhizobium selenitireducens B1 T . The genomic G + C content was 59.4 mol%, and DNA-DNA relatedness with its closest phylogenetic neighbors was 50.2 %. Chemotaxonomy indicated UQ-10 as the major quinone; phosphatidylethanolamine, phosphatidylglycerol, and diphosphatidylglycerol as major polar lipids; C 16:0 , C 17:0 , 2-OH C 10:0 , 3-OH C 16:0 , and unresolved C 18:1 ɷ7C/ɷ9C as predominant fatty acids. The cells were found to reduce O 2 , As 5+ , NO 3 - , SO 4 2- and Fe 3+ as alternate electron acceptors. The strain's ability to metabolize dodecane or other alkanes as sole carbon source using As 5+ as terminal electron acceptor was supported by the presence of genes encoding benzyl succinate synthase (bssA like) and molybdopterin-binding site (mopB) of As 5+ respiratory reductase (arrA). Differential phenotypic, chemotaxonomic, genotypic as well as physiological properties revealed that the strain KAs 5-22 T is separated from its nearest recognized Rhizobium species. On the basis of the data presented, strain KAs 5-22 T is considered to represent a novel species of the genus Rhizobium, for which the name Rhizobium arsenicireducens sp. nov. is proposed as type strain (=LMG 28795 T =MTCC 12115 T ).

  16. Evaluation of SinoRhizobium meliloti Efficiency and Qualitative Traits of Alfalfa under Application of Molybdenum

    Directory of Open Access Journals (Sweden)

    F Ahmadi Dana

    2017-12-01

    Full Text Available Introduction Agriculture depends heavily on nitrogen which is biologically fixed through the symbiotic association between rhizobia and legume plants in nodules located on plant roots. Alfalfa is a legume that should fix most of its own N requirement if it is sufficiently nodulated by viable Rhizobium meliloti inoculums. The process of nitrogen fixation is done by the help of an enzyme called nitrogenase and molybdenum which is an important element in the formation of this compound. Molybdenum is required by plants for protein synthesis and is especially important for legumes as it is needed for nitrogen fixation by rhizobia. Therefore the following research was done aimed on studying the effect of different amount of molybdenum and S. rhizobium bacteria on alfalfa’s yield. Material and Methods Alfalfa (Medicago sativa were grown in a field. The experiment was conducted at Karaj in 2013 in split plot arrangement based on completely randomized block design (RCBD, including 2 caring S. rhizobium inoculated seed and non-inoculated as the main plot factorand 3 levels of Molybdenum (0,5,10 kg ha-1 from ammonium molybdate (as the sub plot factor in three replications. Sinorhizobium meliloti bacteria were cultured on plates. Then half of the seeds were inoculated by Sinorhizobium meliloti. Nitrogen fertilizer was added only in one stage before planting up to 50 kg per hectare. Plants were grown until flowering. The data were analyzed by the SAS (9.1 software and mean comparisons were done by Duncan's MRT at the 1% and 5% probability level. Results and Discussion The results showed the effect of different levels of molybdenum and S. Rhizobium bacteria on dry matter yield, molybdenum concentrations in shoots and roots and the number of root nodules was significant. This treatment was significant in comparison to the control treatment with the14.27 ton per hectare. Increasing of molybdenum application, led to increasing of root nodules and showed a

  17. The crystal structure of Toxoplasma gondii pyruvate kinase 1.

    Directory of Open Access Journals (Sweden)

    Rebecca Bakszt

    2010-09-01

    Full Text Available Pyruvate kinase (PK, which catalyzes the final step in glycolysis converting phosphoenolpyruvate to pyruvate, is a central metabolic regulator in most organisms. Consequently PK represents an attractive therapeutic target in cancer and human pathogens, like Apicomplexans. The phylum Aplicomplexa, a group of exclusively parasitic organisms, includes the genera Plasmodium, Cryptosporidium and Toxoplasma, the etiological agents of malaria, cryptosporidiosis and toxoplasmosis respectively. Toxoplasma gondii infection causes a mild illness and is a very common infection affecting nearly one third of the world's population.We have determined the crystal structure of the PK1 enzyme from T. gondii, with the B domain in the open and closed conformations. We have also characterized its enzymatic activity and confirmed glucose-6-phosphate as its allosteric activator. This is the first description of a PK enzyme in a closed inactive conformation without any bound substrate. Comparison of the two tetrameric TgPK1 structures indicates a reorientation of the monomers with a concomitant change in the buried surface among adjacent monomers. The change in the buried surface was associated with significant B domain movements in one of the interacting monomers.We hypothesize that a loop in the interface between the A and B domains plays an important role linking the position of the B domain to the buried surface among monomers through two α-helices. The proposed model links the catalytic cycle of the enzyme with its domain movements and highlights the contribution of the interface between adjacent subunits. In addition, an unusual ordered conformation was observed in one of the allosteric binding domains and it is related to a specific apicomplexan insertion. The sequence and structural particularity would explain the atypical activation by a mono-phosphorylated sugar. The sum of peculiarities raises this enzyme as an emerging target for drug discovery.

  18. The crystal structure of Toxoplasma gondii pyruvate kinase 1.

    Science.gov (United States)

    Bakszt, Rebecca; Wernimont, Amy; Allali-Hassani, Abdellah; Mok, Man Wai; Hills, Tanya; Hui, Raymond; Pizarro, Juan C

    2010-09-14

    Pyruvate kinase (PK), which catalyzes the final step in glycolysis converting phosphoenolpyruvate to pyruvate, is a central metabolic regulator in most organisms. Consequently PK represents an attractive therapeutic target in cancer and human pathogens, like Apicomplexans. The phylum Aplicomplexa, a group of exclusively parasitic organisms, includes the genera Plasmodium, Cryptosporidium and Toxoplasma, the etiological agents of malaria, cryptosporidiosis and toxoplasmosis respectively. Toxoplasma gondii infection causes a mild illness and is a very common infection affecting nearly one third of the world's population. We have determined the crystal structure of the PK1 enzyme from T. gondii, with the B domain in the open and closed conformations. We have also characterized its enzymatic activity and confirmed glucose-6-phosphate as its allosteric activator. This is the first description of a PK enzyme in a closed inactive conformation without any bound substrate. Comparison of the two tetrameric TgPK1 structures indicates a reorientation of the monomers with a concomitant change in the buried surface among adjacent monomers. The change in the buried surface was associated with significant B domain movements in one of the interacting monomers. We hypothesize that a loop in the interface between the A and B domains plays an important role linking the position of the B domain to the buried surface among monomers through two α-helices. The proposed model links the catalytic cycle of the enzyme with its domain movements and highlights the contribution of the interface between adjacent subunits. In addition, an unusual ordered conformation was observed in one of the allosteric binding domains and it is related to a specific apicomplexan insertion. The sequence and structural particularity would explain the atypical activation by a mono-phosphorylated sugar. The sum of peculiarities raises this enzyme as an emerging target for drug discovery.

  19. The Crystal Structure of Toxoplasma gondii Pyruvate Kinase 1

    Energy Technology Data Exchange (ETDEWEB)

    Bakszt, R.; Wernimont, A; Allali-Hassani, A; Mok, M; Hills, T; Hui, R; Pizarro, J

    2010-01-01

    Pyruvate kinase (PK), which catalyzes the final step in glycolysis converting phosphoenolpyruvate to pyruvate, is a central metabolic regulator in most organisms. Consequently PK represents an attractive therapeutic target in cancer and human pathogens, like Apicomplexans. The phylum Aplicomplexa, a group of exclusively parasitic organisms, includes the genera Plasmodium, Cryptosporidium and Toxoplasma, the etiological agents of malaria, cryptosporidiosis and toxoplasmosis respectively. Toxoplasma gondii infection causes a mild illness and is a very common infection affecting nearly one third of the world's population. We have determined the crystal structure of the PK1 enzyme from T. gondii, with the B domain in the open and closed conformations. We have also characterized its enzymatic activity and confirmed glucose-6-phosphate as its allosteric activator. This is the first description of a PK enzyme in a closed inactive conformation without any bound substrate. Comparison of the two tetrameric TgPK1 structures indicates a reorientation of the monomers with a concomitant change in the buried surface among adjacent monomers. The change in the buried surface was associated with significant B domain movements in one of the interacting monomers. We hypothesize that a loop in the interface between the A and B domains plays an important role linking the position of the B domain to the buried surface among monomers through two {alpha}-helices. The proposed model links the catalytic cycle of the enzyme with its domain movements and highlights the contribution of the interface between adjacent subunits. In addition, an unusual ordered conformation was observed in one of the allosteric binding domains and it is related to a specific apicomplexan insertion. The sequence and structural particularity would explain the atypical activation by a mono-phosphorylated sugar. The sum of peculiarities raises this enzyme as an emerging target for drug discovery.

  20. Brain Glycogenolysis, Adrenoceptors, Pyruvate Carboxylase, Na+,K+-ATPase and Marie E. Gibbs’ Pioneering Learning Studies

    Directory of Open Access Journals (Sweden)

    Leif eHertz

    2013-04-01

    Full Text Available The involvement of glycogenolysis, occurring in astrocytes but not in neurons, in learning is undisputed (Duran et al., JCBFM, in press. According to one school of thought the role of astrocytes for learning is restricted to supply of substrate for neuronal oxidative metabolism. The present ‘perspective’ suggests a more comprehensive and complex role, made possible by lack of glycogen degradation, unless specifically induced by either i activation of astrocytic receptors, perhaps especially beta-adrenergic, or ii even small increases in extracellular K+ concentration above its normal resting level. It discusses i the known importance of glycogenolysis for glutamate formation, requiring pyruvate carboxylation; ii the established role of K+-stimulated glycogenolysis for K+ uptake in cultured astrocytes, which probably indicates that astrocytes are an integral part of cellular K+ homeostasis in the brain in vivo; and iii the plausible role of transmitter-induced glycogenolysis, stimulating Na+,K+-ATPase/NKCC1 activity and thereby contributing both to the post-excitatory undershoot in extracellular K+ concentration and the memory-enhancing effect of transmitter-mediated reduction of slow neuronal afterhyperpolarization (sAHP.

  1. Dual inoculation with an Aarbuscular Mycorrhizal fungus and Rhizobium to facilitate the growth of alfalfa on coal mine substrates

    Energy Technology Data Exchange (ETDEWEB)

    Wu, F.Y.; Bi, Y.L.; Wong, M.H. [China University of Mining & Technology, Beijing (China)

    2009-07-01

    A pot experiment was conducted to investigate the effects of Glomus mosseae and Rhizobium on Medicago sativa grown on three types of coal mine substrates, namely a mixture of coal wastes and sands (CS), coal wastes and fly ash (CF), and fly ash (FA). Inoculation with Rhizobium alone did not result in any growth response but G. mosseae alone displayed a significant effect on plant growth. G. mosseae markedly increased the survival rate of M. sativa in CS substrate. In CF and FA substrates the respective oven dry weights of M. sativa inoculated with G. mosseae were 1.8 and 5.1 times higher than those without inoculation. Based on nitrogen (N), phosphorus (P) and potassium (K) uptake and legume growth, the results also show that dual inoculation in CS and CF substrates elicited a synergistic effect. This indicates that inoculation with arbuscular mycorrhizal (AM) fungi may be a promising approach for revegetation of coal mine substrates.

  2. The beneficial effect of dual inoculation of vesicular-arbuscular mycorrhizae + rhizobium on growth of white clover

    Directory of Open Access Journals (Sweden)

    Lin, XG.

    1993-01-01

    Full Text Available Investigation on the effect of phosphorus on vesicular-arbuscular mycorrhizal infection, and dual inoculation of vesicular-arbuscular mycorrhizae + rhizobium on growth of white clover under field microplots and pot experiments was conducted on fluvo-aquic soils of semi-arid region in north China. The results showed that 60 kg P205 ha in form of superphosphate was the most favorable phosphorus level for vesicular-arbuscular mycorrhizal infection ; mycorrhizal infection, nodulation, dry weight of shoots and roots, total uptake of nitrogen, phosphorus and other elements, the final yields and recovery of phosphorus of white clover were significantly increased by vesicular-arbuscular mycorrhizal inoculation and dual inoculation with vesicular-arbuscular mycorrhizal fungi and rhizobium. The highest response of inoculation was obtained by adding fertilizer phosphorus at the level of 60 kg P205 ha in form of superphosphate.

  3. Inoculation of the nonlegume Capsicum annuum L. with Rhizobium strains. 2. Changes in sterols, triterpenes, fatty acids, and volatile compounds.

    Science.gov (United States)

    Silva, Luís R; Azevedo, Jessica; Pereira, Maria J; Carro, Lorena; Velazquez, Encarna; Peix, Alvaro; Valentão, Patrícia; Andrade, Paula B

    2014-01-22

    Peppers (Capsicum spp.) are consumed worldwide, imparting flavor, aroma, and color to foods, additionally containing high concentrations of biofunctional compounds. This is the first report about the effect of the inoculation of two Rhizobium strains on sterols, triterpenes, fatty acids, and volatile compounds of leaves and fruits of pepper (Capsicum annuum L.) plants. Generally, inoculation with strain TVP08 led to the major changes, being observed a decrease of sterols and triterpenes and an increase of fatty acids, which are related to higher biomass, growth, and ripening of pepper fruits. The increase of volatile compounds may reflect the elicitation of plant defense after inoculation, since the content on methyl salicylate was significantly increased in inoculated material. The findings suggest that inoculation with Rhizobium strains may be employed to manipulate the content of interesting metabolites in pepper leaves and fruits, increasing potential health benefits and defense abilities of inoculated plants.

  4. Pyruvate metabolism: A therapeutic opportunity in radiation-induced skin injury

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Hyun; Kang, Jeong Wook [Department of Radiation Oncology, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Lee, Dong Won [Department of Plastic Surgery, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Oh, Sang Ho [Department of Dermatology, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Lee, Yun-Sil [College of Pharmacy & Division of Life and Pharmaceutical Sciences, Ewah Womans University, Seoul 120-750 (Korea, Republic of); Lee, Eun-Jung [Department of Radiation Oncology, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Cho, Jaeho, E-mail: jjhmd@yuhs.ac [Department of Radiation Oncology, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752 (Korea, Republic of)

    2015-05-08

    Ionizing radiation is used to treat a range of cancers. Despite recent technological progress, radiation therapy can damage the skin at the administration site. The specific molecular mechanisms involved in this effect have not been fully characterized. In this study, the effects of pyruvate, on radiation-induced skin injury were investigated, including the role of the pyruvate dehydrogenase kinase 2 (PDK2) signaling pathway. Next generation sequencing (NGS) identified a wide range of gene expression differences between the control and irradiated mice, including reduced expression of PDK2. This was confirmed using Q-PCR. Cell culture studies demonstrated that PDK2 overexpression and a high cellular pyruvate concentration inhibited radiation-induced cytokine expression. Immunohistochemical studies demonstrated radiation-induced skin thickening and gene expression changes. Oral pyruvate treatment markedly downregulated radiation-induced changes in skin thickness and inflammatory cytokine expression. These findings indicated that regulation of the pyruvate metabolic pathway could provide an effective approach to the control of radiation-induced skin damage. - Highlights: • The effects of radiation on skin thickness in mice. • Next generation sequencing revealed that radiation inhibited pyruvate dehydrogenase kinase 2 expression. • PDK2 inhibited irradiation-induced cytokine gene expression. • Oral pyruvate treatment markedly downregulated radiation-induced changes in skin thickness.

  5. Improved sake metabolic profile during fermentation due to increased mitochondrial pyruvate dissimilation.

    Science.gov (United States)

    Agrimi, Gennaro; Mena, Maria C; Izumi, Kazuki; Pisano, Isabella; Germinario, Lucrezia; Fukuzaki, Hisashi; Palmieri, Luigi; Blank, Lars M; Kitagaki, Hiroshi

    2014-03-01

    Although the decrease in pyruvate secretion by brewer's yeasts during fermentation has long been desired in the alcohol beverage industry, rather little is known about the regulation of pyruvate accumulation. In former studies, we developed a pyruvate under-secreting sake yeast by isolating a strain (TCR7) tolerant to ethyl α-transcyanocinnamate, an inhibitor of pyruvate transport into mitochondria. To obtain insights into pyruvate metabolism, in this study, we investigated the mitochondrial activity of TCR7 by oxigraphy and (13) C-metabolic flux analysis during aerobic growth. While mitochondrial pyruvate oxidation was higher, glycerol production was decreased in TCR7 compared with the reference. These results indicate that mitochondrial activity is elevated in the TCR7 strain with the consequence of decreased pyruvate accumulation. Surprisingly, mitochondrial activity is much higher in the sake yeast compared with CEN.PK 113-7D, the reference strain in metabolic engineering. When shifted from aerobic to anaerobic conditions, sake yeast retains a branched mitochondrial structure for a longer time than laboratory strains. The regulation of mitochondrial activity can become a completely novel approach to manipulate the metabolic profile during fermentation of brewer's yeasts. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  6. Mitochondrial Pyruvate Carrier 2 Hypomorphism in Mice Leads to Defects in Glucose-Stimulated Insulin Secretion

    Directory of Open Access Journals (Sweden)

    Patrick A. Vigueira

    2014-06-01

    Full Text Available Carrier-facilitated pyruvate transport across the inner mitochondrial membrane plays an essential role in anabolic and catabolic intermediary metabolism. Mitochondrial pyruvate carrier 2 (Mpc2 is believed to be a component of the complex that facilitates mitochondrial pyruvate import. Complete MPC2 deficiency resulted in embryonic lethality in mice. However, a second mouse line expressing an N-terminal truncated MPC2 protein (Mpc2Δ16 was viable but exhibited a reduced capacity for mitochondrial pyruvate oxidation. Metabolic studies demonstrated exaggerated blood lactate concentrations after pyruvate, glucose, or insulin challenge in Mpc2Δ16 mice. Additionally, compared with wild-type controls, Mpc2Δ16 mice exhibited normal insulin sensitivity but elevated blood glucose after bolus pyruvate or glucose injection. This was attributable to reduced glucose-stimulated insulin secretion and was corrected by sulfonylurea KATP channel inhibitor administration. Collectively, these data are consistent with a role for MPC2 in mitochondrial pyruvate import and suggest that Mpc2 deficiency results in defective pancreatic β cell glucose sensing.

  7. The beneficial effect of dual inoculation of vesicular-arbuscular mycorrhizae + rhizobium on growth of white clover

    OpenAIRE

    Lin, XG.; Hao, WY.; Wu, TH.

    1993-01-01

    Investigation on the effect of phosphorus on vesicular-arbuscular mycorrhizal infection, and dual inoculation of vesicular-arbuscular mycorrhizae + rhizobium on growth of white clover under field microplots and pot experiments was conducted on fluvo-aquic soils of semi-arid region in north China. The results showed that 60 kg P205 ha in form of superphosphate was the most favorable phosphorus level for vesicular-arbuscular mycorrhizal infection ; mycorrhizal infection, nodulation, dry weight ...

  8. Single pyruvate intake induces blood alkalization and modification of resting metabolism in humans.

    Science.gov (United States)

    Olek, Robert A; Luszczyk, Marcin; Kujach, Sylwester; Ziemann, Ewa; Pieszko, Magdalena; Pischel, Ivo; Laskowski, Radoslaw

    2015-03-01

    Three separate studies were performed with the aim to 1) determine the effect of a single sodium pyruvate intake on the blood acid-base status in males and females; 2) compare the effect of sodium and calcium pyruvate salts and establish their role in the lipolysis rate; and 3) quantify the effect of single pyruvate intake on the resting energy metabolism. In all, 48 individuals completed three separate studies. In all the studies, participants consumed a single dose of pyruvate 0.1 g/kg 60 min before commencing the measurements. The whole blood pH, bicarbonate concentration, base excess or plasma glycerol, free fatty acids, glucose concentrations, or resting energy expenditure and calculated respiratory exchange ratio were determined. The analysis of variance for repeated measurements was performed to examine the interaction between treatment and time. The single dose of sodium pyruvate induced blood alkalization, which was more marked in the male than in the female participants. Following the ingestion of sodium or calcium pyruvate, the blood acid-base parameters were higher than in the placebo trial. Furthermore, 3-h postingestion glycerol was lower in both pyruvate trials than in placebo. Resting energy expenditure did not differ between the trials; however, carbohydrate oxidation was increased after sodium pyruvate ingestion. Pyruvate intake induced mild alkalization in a sex-dependent fashion. Moreover, it accelerated carbohydrate metabolism and delayed the rate of glycerol appearance in the blood, but had no effect on the resting energy expenditure. Furthermore, sodium salt seems to have had a greater effect on the blood buffering level than calcium salt. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. VARIATION IN RHIZOBIUM GROWTH DUE TO SEED AND ROOT EXUDATES RELEASED FROM GAMMA IRRADIATED GLYCINE MAX SEEDS

    International Nuclear Information System (INIS)

    KAMEL, H.A.; ASKER, M.M.S

    2008-01-01

    In this study, seeds of Glycine max Giza 122 were irradiated with gamma rays from 60 Co source at various doses (10 to 200 Gy), sterilized and soaked into an aerated solution of CaSO 4 (1 mmol and pH 6.5). The capacities of the released seed exudates (SEs) and root exudates (REs) to promote Rhizobium leguminosarum growth were investigated as well as biochemical analysis of the exudates was carried out. SE of both control and gamma irradiated seeds resulted in a higher Rhizobium population and polysaccharide production than RE. Relative to control, the highly effective doses in Rhizobium growth and polysaccharide production were 25 and 200 Gy; the former was a promoter while the later was an inhibitor. HPLC analysis of soluble carbohydrates revealed the presence of glucose (Glu), rhamnose (Rha) and fructose (Fru) in the SE and RE. Protein content in SE was lower than that in RE; the highest values were due to 10 Gy and 25 Gy in SE and RE, respectively. Free amino acids content in SE was increased up to 25 Gy then decreased while RE was increased by increasing gamma doses from 10 to 200 Gy

  10. Symbiont effect of Rhizobium bacteria and vesicular arbuscular mycorrhizal fungi on Pisum sativum in recultivated mine spoils

    Energy Technology Data Exchange (ETDEWEB)

    Biro, B.; Voros, I.; Kovespechy, K.; Szegi, J. (Hungarian Academy of Sciences, Budapest (Hungary). Soil Science and Agricultural Chemistry Research Institute)

    The frequency (F%) of spontaneous endomycorrhizal fungal infection (AMF) and the root modulation of Pisum sativum L, was studied after 8 and 15 years of recultivation in 4 soils (andesitic tuff yellow sand, yellow clay, and grey clay) disturbed by mining activities. The effects of Rhizobium inoculation and the interaction of both microsymbionts with plant production were also examined along with humus content and the humus stability coefficient, in the following variations: control, NPK fertilizer, NPK+lignite, NPK+straw and sewage sludge. Dump spoils originating from deep geological layers were poor in organic materials. After 12 years of recultivation, the humus content increased significantly. No such increase was noted in grey clay and the natural, brown forest soil used as an undisturbed (control) sample. The degradation of soils by mining brings about a decrease in the rhizobial and mycorrhizal population, so the number of spontaneous Rhizobium nodules is relatively low and does not influence the yield of peas. Inoculation with a selected effective strain of Rhizobium leguminosarum bv. viceae, however, enhanced dry matter production in these microbiologically degraded soils. Although the frequency of AMF infection was also higher after rhizobial inoculation, no positive correlation was found between dry matter production of peas and the F% of AMF. Spoils treated with lignite, straw, and sewage sludge had an especially high level of spontaneous mycorrhizal populations, indicating that organic materials had a favorable effect on the recultivation processes and fertility of mine spoils.

  11. A Legume TOR Protein Kinase Regulates Rhizobium Symbiosis and Is Essential for Infection and Nodule Development1[OPEN

    Science.gov (United States)

    Blanco, Lourdes; Quinto, Carmen

    2016-01-01

    The target of rapamycin (TOR) protein kinase regulates metabolism, growth, and life span in yeast, animals, and plants in coordination with nutrient status and environmental conditions. The nutrient-dependent nature of TOR functionality makes this kinase a putative regulator of symbiotic associations involving nutrient acquisition. However, TOR’s role in these processes remains to be understood. Here, we uncovered the role of TOR during the bean (Phaseolus vulgaris)-Rhizobium tropici (Rhizobium) symbiotic interaction. TOR was expressed in all tested bean tissues, with higher transcript levels in the root meristems and senesced nodules. We showed TOR promoter expression along the progressing infection thread and in the infected cells of mature nodules. Posttranscriptional gene silencing of TOR using RNA interference (RNAi) showed that this gene is involved in lateral root elongation and root cell organization and also alters the density, size, and number of root hairs. The suppression of TOR transcripts also affected infection thread progression and associated cortical cell divisions, resulting in a drastic reduction of nodule numbers. TOR-RNAi resulted in reduced reactive oxygen species accumulation and altered CyclinD1 and CyclinD3 expression, which are crucial factors for infection thread progression and nodule organogenesis. Enhanced expression of TOR-regulated ATG genes in TOR-RNAi roots suggested that TOR plays a role in the recognition of Rhizobium as a symbiont. Together, these data suggest that TOR plays a vital role in the establishment of root nodule symbiosis in the common bean. PMID:27698253

  12. Rhizobium Impacts on Seed Productivity, Quality, and Protection of Pisum sativum upon Disease Stress Caused by Didymella pinodes: Phenotypic, Proteomic, and Metabolomic Traits

    Directory of Open Access Journals (Sweden)

    Nima Ranjbar Sistani

    2017-11-01

    Full Text Available In field peas, ascochyta blight is one of the most common fungal diseases caused by Didymella pinodes. Despite the high diversity of pea cultivars, only little resistance has been developed until to date, still leading to significant losses in grain yield. Rhizobia as plant growth promoting endosymbionts are the main partners for establishment of symbiosis with pea plants. The key role of Rhizobium as an effective nitrogen source for legumes seed quality and quantity improvement is in line with sustainable agriculture and food security programs. Besides these growth promoting effects, Rhizobium symbiosis has been shown to have a priming impact on the plants immune system that enhances resistance against environmental perturbations. This is the first integrative study that investigates the effect of Rhizobium leguminosarum bv. viceae (Rlv on phenotypic seed quality, quantity and fungal disease in pot grown pea (Pisum sativum cultivars with two different resistance levels against D. pinodes through metabolomics and proteomics analyses. In addition, the pathogen effects on seed quantity components and quality are assessed at morphological and molecular level. Rhizobium inoculation decreased disease severity by significant reduction of seed infection level. Rhizobium symbiont enhanced yield through increased seed fresh and dry weights based on better seed filling. Rhizobium inoculation also induced changes in seed proteome and metabolome involved in enhanced P. sativum resistance level against D. pinodes. Besides increased redox and cell wall adjustments light is shed on the role of late embryogenesis abundant proteins and metabolites such as the seed triterpenoid Soyasapogenol. The results of this study open new insights into the significance of symbiotic Rhizobium interactions for crop yield, health and seed quality enhancement and reveal new metabolite candidates involved in pathogen resistance.

  13. Perturabation of nodular operation under salt and water deficit stress in rhizobium common bean symbiosis

    International Nuclear Information System (INIS)

    Harzalli Jebara, Salwa

    2006-01-01

    This work aims at the search for markers of tolerance to the osmotic stress and nodular efficiency of symbiosis Haricot Rhizobium. Thus, after having fixed the best period of hydroponic culture, we showed that a severe salt treatment generated an inhibition of the parameters of growth and nodulation. These inhibitions are accompanied by an inhibition of the enzymatic activities: ascorbate peroxidase (APX) and catalase (CAT), but an activation of peroxidase (POX) and superoxide dismutase (SOD), suggesting that these two antioxydants can be biochemical markers of the tolerance to salinity. To check the validity of these markers and to see the participation of the vegetable genotype in the response to the stress, we compared the effect of two concentrations salt 25 and 50 mM NaCe at two contrasting genotypes BAT477 tolerant and sensitive COCOT. This study illustrates the role of the vegetable genotype in the tolerance and efficiency and emphasize a significant result that SOD and POX constitute biochemical markers of tolerance to salinity. In order to ensure itself of the validity of this assumption in the event of water deficit stress, a treatment of 50 mM mannitol is applied to 16 symbioses formed by four genotypes of bean BAT477, COCOT, Flamingo and BRB17 inoculated by four strains of rhizobium CIAT899, 12 to 3, 1 to 6 and 8 to 3. This study permits us to make a screening of these symbioses according to their efficiency and their tolerance based on parameters of growth, of fixing and extent of the antioxydant enzymatic activities. It gets clear that the response of enzymatic antioxydants is in relation to the intrinsic potentialities of the partners of symbioses and appears to act as of the first stages of recognition plants bacterium. It will be retained that activities POX and SOD are markers of nodular tolerance. The CAT is the enzyme most connected to each partner of symbiosis and the APX would play a rather functional role. The heterogeneity of found answer

  14. Effects of pyruvate dose on in vivo metabolism and quantification of hyperpolarized 13C spectra

    DEFF Research Database (Denmark)

    Janich, M. A.; Menzel, M. I.; Wiesinger, F.

    2012-01-01

    Real‐time in vivo measurements of metabolites are performed by signal enhancement of [1‐13C]pyruvate using dynamic nuclear polarization, rapid dissolution and intravenous injection, acquisition of free induction decay signals and subsequent quantification of spectra. The commonly injected dose...... uptake and metabolic conversion. The goal of this study was to examine the effects of a [1‐13C]pyruvate bolus on metabolic conversion in vivo. Spectra were quantified by three different methods: frequency‐domain fitting with LCModel, time‐domain fitting with AMARES and simple linear least‐squares fitting...... in the time domain. Since the simple linear least‐squares approach showed bleeding artifacts and LCModel produced noisier time signals. AMARES performed best in the quantification of in vivo hyperpolarized pyruvate spectra. We examined pyruvate doses of 0.1–0.4 mmol/kg (body mass) in male Wistar rats...

  15. A pyruvate-buffered dialysis fluid induces less peritoneal angiogenesis and fibrosis than a conventional solution

    NARCIS (Netherlands)

    van Westrhenen, Roos; Zweers, Machteld M.; Kunne, Cindy; de Waart, Dirk R.; van der Wal, Allard C.; Krediet, Raymond T.

    2008-01-01

    BACKGROUND: Conventional lactate-buffered peritoneal dialysis (PD) fluids containing glucose and glucose degradation products are believed to contribute to the development of fibrosis and angiogenesis in the dialyzed peritoneum. To reduce potential negative effects of lactate, pyruvate was

  16. Molecular structure of the pyruvate dehydrogenase complex from Escherichia coli K-12.

    Science.gov (United States)

    Vogel, O; Hoehn, B; Henning, U

    1972-06-01

    The pyruvate dehydrogenase core complex from E. coli K-12, defined as the multienzyme complex that can be obtained with a unique polypeptide chain composition, has a molecular weight of 3.75 x 10(6). All results obtained agree with the following numerology. The core complex consists of 48 polypeptide chains. There are 16 chains (molecular weight = 100,000) of the pyruvate dehydrogenase component, 16 chains (molecular weight = 80,000) of the dihydrolipoamide dehydrogenase component, and 16 chains (molecular weight = 56,000) of the dihydrolipoamide dehydrogenase component. Usually, but not always, pyruvate dehydrogenase complex is produced in vivo containing at least 2-3 mol more of dimers of the pyruvate dehydrogenase component than the stoichiometric ratio with respect to the core complex. This "excess" component is bound differently than are the eight dimers in the core complex.

  17. Effect of hexoses on the levels of pyruvate decarboxylase in Mucor rouxii.

    OpenAIRE

    Barrera, C R; Corral, J

    1980-01-01

    Pyruvate decarboxylase activity in the dimorphic fungus Mucor rouxii increased 25- to 35-fold in yeastlike and mycelial cells grown in the presence of glucose as compared to the activity observed in mycelial cultures grown in the absence of glucose.

  18. Changes in myocardial lactate, pyruvate and lactate-pyruvate ratio during cardiopulmonary bypass for elective adult cardiac surgery: Early indicator of morbidity

    Directory of Open Access Journals (Sweden)

    P M Kapoor

    2011-01-01

    Full Text Available Background: Myocardial lactate assays have been established as a standard method to compare various myocardial protection strategies. This study was designed to test whether coronary sinus (CS lactates, pyruvate and lactate-pyruvate (LP ratio correlates with myocardial dysfunction and predict postoperative outcomes. Materials and Methods: This prospective observational study was conducted on 40 adult patients undergoing elective cardiac surgery with the aid of cardiopulmonary bypass (CPB. CS blood sampling was done for estimation of myocardial lactate (ML, pyruvate (MP and lactate-pyruvate ratio (MLPR namely: pre-CPB (T 1 , after removal of aortic cross clamp (T 2 and 30 minutes post-CPB (T 3 . Results: Baseline myocardial LPR strongly correlated with Troponin-I at T1 (s: 0.6. Patients were sub grouped according to the median value of myocardial lactate (2.9 at baseline T1 into low myocardial lactate (LML group, mean (2.39±0.4 mmol/l, n=19 and a high myocardial lactate (HML group, mean (3.65±0.9 mmol/l, n=21. A significant increase in PL, ML, MLPR and TropI occurred in both groups as compared to baseline. Patients in HML group had significant longer period of ICU stay. Patients with higher inotrope score had significantly higher ML (T2, T3. ML with a baseline value of 2.9 mmol/l had 70.83% sensitivity and 62.5% specificity (ROC area: 0.7109 Std error: 0.09 while myocardial pyruvate with a baseline value of 0.07 mmol/l has 79.17% sensitivity and 68.75% specificity (ROC area: 0.7852, Std error: 0.0765 for predicting inotrope requirement after CPB. Conclusion: CS lactate, pyruvate and LP ratio correlate with myocardial function and can predict postoperative outcome.

  19. Cancer metabolism meets systems biology: Pyruvate kinase isoform PKM2 is a metabolic master regulator

    OpenAIRE

    Fabian V Filipp

    2013-01-01

    Pyruvate kinase activity is controlled by a tightly woven regulatory network. The oncofetal isoform of pyruvate kinase (PKM2) is a master regulator of cancer metabolism. PKM2 engages in parallel, feed-forward, positive and negative feedback control contributing to cancer progression. Besides its metabolic role, non-metabolic functions of PKM2 as protein kinase and transcriptional coactivator for c-MYC and hypoxia-inducible factor 1-alpha are essential for epidermal growth factor receptor acti...

  20. Pyruvate incubation enhances glycogen stores and sustains neuronal function during subsequent glucose deprivation.

    Science.gov (United States)

    Shetty, Pavan K; Sadgrove, Matthew P; Galeffi, Francesca; Turner, Dennis A

    2012-01-01

    The use of energy substrates, such as lactate and pyruvate, has been shown to improve synaptic function when administered during glucose deprivation. In the present study, we investigated whether prolonged incubation with monocarboxylate (pyruvate or lactate) prior rather than during glucose deprivation can also sustain synaptic and metabolic function. Pyruvate pre-incubation(3-4h) significantly prolonged (>25 min) the tolerance of rat hippocampal slices to delayed glucose deprivation compared to control and lactate pre-incubated slices, as revealed by field excitatory post synaptic potentials (fEPSPs); pre-incubation with pyruvate also reduced the marked decrease in NAD(P)H fluorescence resulting from glucose deprivation. Moreover, pyruvate exposure led to the enhancement of glycogen stores with time, compared to glucose alone (12 μmol/g tissue at 4h vs. 3.5 μmol/g tissue). Prolonged resistance to glucose deprivation following exogenous pyruvate incubation was prevented by glycogenolysis inhibitors, suggesting that enhanced glycogen mediates the delay in synaptic activity failure. The application of an adenosine A1 receptor antagonist enhanced glycogen utilization and prolonged the time to synaptic failure, further confirming this hypothesis of the importance of glycogen. Moreover, tissue levels of ATP were also significantly maintained during glucose deprivation in pyruvate pretreated slices compared to control and lactate. In summary, these experiments indicate that pyruvate exposure prior to glucose deprivation significantly increased the energy buffering capacity of hippocampal slices, particularly by enhancing internal glycogen stores, delaying synaptic failure during glucose deprivation by maintaining ATP levels, and minimizing the decrease in the levels of NAD(P)H. Copyright © 2011 Elsevier Inc. All rights reserved.

  1. Selection of Rhizobium strain from Wonogiri, Central Java on the growth of soybean (Glycine max L. on the sand sterile medium in greenhouse

    Directory of Open Access Journals (Sweden)

    SRI PURWANINGSIH

    2005-07-01

    Full Text Available An experiment on the selection of Rhizobium strain from Wonogiri, Central Java on the growth of soybean (Glycine max L. on the sand sterile medium in green house. The aim of the experiment the selection and potency of the Rhizobium strain to increase the growth of soybean. The experiment was carried out in green house condition in Microbiology Division, Research Center for Biology-LIPI with sterile sand medium. The research design was Completely Randomized Design with three replications for each treatment. The Rhizobium strains used were 1 W (isolated from bean, Vigna radiata, 2 W (isolated from soybean, 3 W (isolated from bean, 4 W (isolated from soybean, 5 W (isolated from soybean, 6 W (isolated from peanut, Arachis hypogaea, 7 W (isolated from peanut, 8 W (isolated from peanut, the controls were uninoculated with Rhizobium strain and without urea fertilizer (K1, uninoculated and with urea fertilizer equal 100 kg/ha (K2. The plants were harvested after 50 days, the variable of investigation were the dry weight of canopy, roots, nodules root, total plants, number of nodules and ‘symbiotic capacity”. The results showed that all of experiment plant which be inoculated with Rhizobium able to form nodule. Strain of 2 W (isolated from soybean has given the best effects on the growth of soybean.

  2. Pyruvate Decarboxylase Activity Assay in situ of Different Industrial Yeast Strains

    Directory of Open Access Journals (Sweden)

    Dorota Kręgiel

    2009-01-01

    Full Text Available Cytoplasmic pyruvate decarboxylase (PDC, EC 4.1.1.1 is one of the key enzymes of yeast fermentative metabolism. PDC is the first enzyme which, under anaerobic conditions, leads to decarboxylation of pyruvate with acetaldehyde as the end product. The aim of this study is to develop a suitable method for PDC activity assay in situ for different industrial yeast strains. Saccharomyces sp. and Debaryomyces sp. yeast strains grew in fermentative medium with 12 % of glucose. Enzymatic assay was conducted in cell suspension treated with digitonin as permeabilisation agent, and with sodium pyruvate as a substrate, at temperature of 30 °C. Metabolites of PDC pathway were detected using gas chromatographic (GC technique. Various parameters like type and molar concentration of the substrate, minimal effective mass fraction of digitonin, cell concentration, reaction time and effect of pyrazole (alcohol dehydrogenase inhibitor were monitored to optimize PDC enzymatic assay in situ. In the concentration range of yeast cells from 1⋅10^7 to 1⋅10^8 per mL, linear correlation between the produced acetaldehyde and cell density was noticed. Only pyruvate was the specific substrate for pyruvate decarboxylase. In the presence of 0.05 M sodium pyruvate and 0.05 % digitonin, the enzymatic reaction was linear up to 20 min of the assay. During incubation, there was no formation of ethanol and, therefore, pyrazole was not necessary for the assay.

  3. Pyruvate dehydrogenase kinase inhibition: Reversing the Warburg effect in cancer therapy

    Directory of Open Access Journals (Sweden)

    Hayden Bell

    2016-06-01

    Full Text Available The poor efficacy of many cancer chemotherapeutics, which are often non-selective and highly toxic, is attributable to the remarkable heterogeneity and adaptability of cancer cells. The Warburg effect describes the up regulation of glycolysis as the main source of adenosine 5’-triphosphate in cancer cells, even under normoxic conditions, and is a unique metabolic phenotype of cancer cells. Mitochondrial suppression is also observed which may be implicated in apoptotic suppression and increased funneling of respiratory substrates to anabolic processes, conferring a survival advantage. The mitochondrial pyruvate dehydrogenase complex is subject to meticulous regulation, chiefly by pyruvate dehydrogenase kinase. At the interface between glycolysis and the tricarboxylic acid cycle, the pyruvate dehydrogenase complex functions as a metabolic gatekeeper in determining the fate of glucose, making pyruvate dehydrogenase kinase an attractive candidate in a bid to reverse the Warburg effect in cancer cells. The small pyruvate dehydrogenase kinase inhibitor dichloroacetate has, historically, been used in conditions associated with lactic acidosis but has since gained substantial interest as a potential cancer chemotherapeutic. This review considers the Warburg effect as a unique phenotype of cancer cells in-line with the history of and current approaches to cancer therapies based on pyruvate dehydrogenase kinase inhibition with particular reference to dichloroacetate and its derivatives.

  4. Decarboxylation of oxalacetate to pyruvate by purified avian liver phosphoenolpyruvate carboxykinase

    Energy Technology Data Exchange (ETDEWEB)

    Noce, P S; Utter, M F

    1975-01-01

    Phosphoenolpyruvate carboxykinase, which has been isolated from chicken liver mitochondria in essentially homogenous form, carries out the irreversible decarboxylation of oxalacetate to pyruvate in the presence of catalytic amounts of GDP or IDP, as well as the reversible decarboxylation of oxalacetate to phosphoenolpyruvate in the presence of substrate amounts of GTP or ITP. The pyruvate- and phosphoenolpyruvate-forming reactions are similar in their nucleoside specificity and appear to be carried out by the same protein. However, the two activities vary markedly in their response to added metal ions and sulfhydryl reagents. Phosphoenolpyruvate formation is completely dependent on the presence of a divalent metal ion, with Mn/sup 2 +/ the most effective species. This reaction is also stimulated by sulfhydryl reagents such as 2-mercaptoethanol. In contrast, the pyruvate-forming reaction is strongly inhibited by divalent metal ions, including Mn/sup 2 +/, and also by moderate concentrations of sulfhydryl reagents. These observations and the demonstration that pyruvate kinase-like activity is very low or absent make it unlikely that pyruvate formation proceeds via phosphoenolpyruvate as an intermediate. Although the pyruvate-forming reaction is inhibited by added metal ions, the reaction is also inhibited by metal-chelating agents such as 8-hydroxyquinoline and o-phenanthroline, suggesting that the reaction is dependent on the presence of a metal ion. It has not been possible, however, to demonstrate that the enzyme is a metalloprotein.

  5. Supplementation of pyruvate prevents palmitate-induced impairment of glucose uptake in C2 myotubes.

    Science.gov (United States)

    Jung, Jong Gab; Choi, Sung-E; Hwang, Yoon-Jung; Lee, Sang-A; Kim, Eun Kyoung; Lee, Min-Seok; Han, Seung Jin; Kim, Hae Jin; Kim, Dae Jung; Kang, Yup; Lee, Kwan-Woo

    2011-10-15

    Elevated fatty acid levels have been thought to contribute to insulin resistance. Repression of the glucose transporter 4 (GLUT4) gene as well as impaired GLUT4 translocation may be a mediator for fatty acid-induced insulin resistance. This study was initiated to determine whether palmitate treatment repressed GLUT4 expression, whether glucose/fatty acid metabolism influenced palmitate-induced GLUT4 gene repression (PIGR), and whether attempts to prevent PIGR restored palmitate-induced impairment of glucose uptake (PIIGU) in C2 myotubes. Not only stimulators of fatty acid oxidation, such as bezafibrate, AICAR, and TOFA, but also TCA cycle substrates, such as pyruvate, leucine/glutamine, and α-ketoisocaproate/monomethyl succinate, significantly prevented PIGR. In particular, supplementing with pyruvate through methyl pyruvate resulted in nearly complete prevention of PIIGU, whereas palmitate treatment reduced the intracellular pyruvate level. These results suggest that pyruvate depletion plays a critical role in PIGR and PIIGU; thus, pyruvate supplementation may help prevent obesity-induced insulin resistance in muscle cells. Crown Copyright © 2011. Published by Elsevier Ireland Ltd. All rights reserved.

  6. Transformation of pWWO in Rhizobium leguminosarum DPT to Engineer Toluene Degrading Ability for Rhizoremediation.

    Science.gov (United States)

    Goel, Garima; Pandey, Piyush; Sood, Anchal; Bisht, Sandeep; Maheshwari, D K; Sharma, G D

    2012-06-01

    Rhizoremediation of organic xenobiotics is based on interactions between plants and their associated micro-organisms. The present work was designed to engineer a bacterial system having toluene degradation ability along with plant growth promoting characteristics for effective rhizoremediation. pWWO harboring the genes responsible for toluene breakdown was isolated from Pseudomonas putida MTCC 979 and successfully transformed in Rhizobium DPT. This resulted in a bacterial strain (DPT(T)) which had the ability to degrade toluene as well as enhance growth of host plant. The frequency of transformation was recorded 5.7 × 10(-6). DPT produced IAA, siderophore, chitinase, HCN, ACC deaminase, solubilized inorganic phosphate, fixed atmospheric nitrogen and inhibited the growth of Fusarium oxysporum and Macrophomina phaseolina in vitro. During pot assay, 50 ppm toluene in soil was found to inhibit the germination of Cajanus cajan seeds. However when the seeds bacterized with toluene degrading P. putida or R. leguminosarum DPT were sown in pots, again no germination was observed. Non-bacterized as well as bacterized seeds germinated successfully in toluene free soil as control. The results forced for an alternative mode of application of bacteria for rhizoremediation purpose. Hence bacterial suspension was mixed with soil having 50 ppm of toluene. Germination index in DPT treated soil was 100% while in P. putida it was 50%. Untreated soil with toluene restricted the seeds to germinate.

  7. Rhizobium Strain Effects on Yield and Bleeding Sap Amino Compounds in Pisum sativum

    DEFF Research Database (Denmark)

    Rosendahl, Lis

    1984-01-01

    Bleeding sap composition, dry matter production and N distribution in pea (P. sativum L. cv. Bodil) grown with and without nitrate and nodulated with either R. leguminosarum strain 128c53 or strain 1044 were compared. Nitrate increased the total dry matter production of both symbioses, but decrea......Bleeding sap composition, dry matter production and N distribution in pea (P. sativum L. cv. Bodil) grown with and without nitrate and nodulated with either R. leguminosarum strain 128c53 or strain 1044 were compared. Nitrate increased the total dry matter production of both symbioses...... relative to the total N-accumulation was greater with strain 128c53 due to a higher production of nodule tissue. The root bleeding sap of the symbiosis with the greater yield (strain 1044) contained high levels of asparagine and aspartic acid. In the 128c53 symbiosis, glutamine plus homoserine accounted...... for a higher percentage of the organic solutes transporting newly assimilated N from the root system than in the association with 1044. The Rhizobium strain effect on amino compound composition of the bleeding sap may indicate an influence of the bacteroids on either the N-assimilatory enzyme system...

  8. Effect of different substrates on growth of Mimosa bimucronata seedlings inoculate with rhizobium

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    Juliana Müller Freire

    2017-06-01

    Full Text Available The objective of this study was to evaluate the growth response of Mimosa bimucronata (DC O. Kuntze seedlings in nursery conditions to inoculation with rhizobium strains previously selected using different substrates. An experimental design of randomized blocks with split plots was used, testing three substrates (pure organic-containing clay, sand and manure in 1: 1: 1 v: v: v ratio; organomineral mixed with 30% straw and sand with vermiculite in 1: 1 v: v and four N sources (inoculation with strains BR 3461 and BR 3470, control with N fertilization and control without fertilization, totalizing 12 treatments. Height and stem diameter were evaluate after 90 days and shoot, root and nodules dry mass were evaluate after 120 days. Organomineral substrates provided better seedling growth. However, only organic-substrate with straw and sand with vermiculite showed positive responses of plants inoculated with BR3470 strain. The performance of the inoculated seedlings was not higher than that of seedlings fertilized with N. The rate of N applied stimulated nodulation rather than inhibit it.

  9. Rhizobium radiobacter Endocarditis in an Intravenous Drug User: Clinical Presentation, Diagnosis, and Treatment.

    Science.gov (United States)

    Zahoor, Bilal A

    2016-08-01

    Rhizobium radiobacter, a soil-based organism, is not, usually, pathogenic unless in the immunecompromised. Endocarditis, in the immunocompromised, is a typical presentation generally as a result of catheter-based infections. We describe the presentation of R. radiobacter prosthetic valve endocarditis and the inherent challenges in its presentation and diagnosis. A patient presented with acute limb ischemia secondary to R. radiobacter-mediated endocarditis and subsequent thromboembolization of the distal superior femoral and proximal popliteal arteries in the left lower limb. He underwent an uneventful thrombolectomy that restored blood flow distal to the occlusion and restored the patency of the affected arteries. Postoperatively, the patient maintained several unexplained febrile episodes. Blood cultures remained negative for infection. A cardiac work-up demonstrated the presence of vegetative growth on the prosthetic mitral and native aortic valves. Histopathologic analysis of the extracted thrombus confirmed the presence of R. radiobacter. On further history, it was elucidated that the patient was an intravenous drug user who routinely stored drug paraphernalia in plant beds. The patient recovered uneventfully after Piptazobactam was administered. R. radiobacter, and similarly other soil-based pathogens, should be considered as a potential source of endocarditic infection and thromboembolization in patients who similarly describe a history of intravenous drug use. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Genomic basis of broad host range and environmental adaptability of Rhizobium tropici CIAT 899 and Rhizobium sp. PRF 81 which are used in inoculants for common bean (Phaseolus vulgaris L.

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    Ormeño-Orrillo Ernesto

    2012-12-01

    Full Text Available Abstract Background Rhizobium tropici CIAT 899 and Rhizobium sp. PRF 81 are α-Proteobacteria that establish nitrogen-fixing symbioses with a range of legume hosts. These strains are broadly used in commercial inoculants for application to common bean (Phaseolus vulgaris in South America and Africa. Both strains display intrinsic resistance to several abiotic stressful conditions such as low soil pH and high temperatures, which are common in tropical environments, and to several antimicrobials, including pesticides. The genetic determinants of these interesting characteristics remain largely unknown. Results Genome sequencing revealed that CIAT 899 and PRF 81 share a highly-conserved symbiotic plasmid (pSym that is present also in Rhizobium leucaenae CFN 299, a rhizobium displaying a similar host range. This pSym seems to have arisen by a co-integration event between two replicons. Remarkably, three distinct nodA genes were found in the pSym, a characteristic that may contribute to the broad host range of these rhizobia. Genes for biosynthesis and modulation of plant-hormone levels were also identified in the pSym. Analysis of genes involved in stress response showed that CIAT 899 and PRF 81 are well equipped to cope with low pH, high temperatures and also with oxidative and osmotic stresses. Interestingly, the genomes of CIAT 899 and PRF 81 had large numbers of genes encoding drug-efflux systems, which may explain their high resistance to antimicrobials. Genome analysis also revealed a wide array of traits that may allow these strains to be successful rhizosphere colonizers, including surface polysaccharides, uptake transporters and catabolic enzymes for nutrients, diverse iron-acquisition systems, cell wall-degrading enzymes, type I and IV pili, and novel T1SS and T5SS secreted adhesins. Conclusions Availability of the complete genome sequences of CIAT 899 and PRF 81 may be exploited in further efforts to understand the interaction of tropical

  11. Assessing the transport rate of hyperpolarized pyruvate and lactate from the intra- to the extracellular space.

    Science.gov (United States)

    Reineri, Francesca; Daniele, Valeria; Cavallari, Eleonora; Aime, Silvio

    2016-08-01

    The use of [1-(13) C]pyruvate hyperpolarized by means of dynamic nuclear polarization provides a direct way to track the metabolic transformations of this metabolite in vivo and in cell cultures. The identification of the intra- and extracellular contributions to the (13) C NMR resonances is not straightforward. In order to obtain information about the rate of pyruvate and lactate transport through the cellular membrane, we set up a method that relies on the sudden 'quenching' of the extracellular metabolites' signal. The paramagnetic Gd-tetraazacyclododecane triacetic acid (Gd-DO3A) complex was used to dramatically decrease the longitudinal relaxation time constants of the (13) C-carboxylate resonances of both pyruvate and lactate. When Gd-DO3A was added to an MCF-7 cellular culture, which had previously received a dose of hyperpolarized [1-(13) C]pyruvate, the contributions of the extracellular pyruvate and lactate signals were deleted. From the analysis of the decay curves of the (13) C-carboxylate resonances of pyruvate and lactate it was possible to extract information about the exchange rate of the two metabolites across the cellular membrane. In particular, it was found that, in the reported experimental conditions, the lactate transport from the intra- to the extracellular space is not much lower than the rate of lactate formation. The method reported herein is non-destructive and it could be translated to in vivo studies. It opens a route for the use of hyperpolarized pyruvate to assess altered activity of carboxylate transporter proteins that may occur in pathological conditions. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  12. Ethyl Pyruvate Ameliorates Hepatic Ischemia-Reperfusion Injury by Inhibiting Intrinsic Pathway of Apoptosis and Autophagy

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    Miao Shen

    2013-01-01

    Full Text Available Background. Hepatic ischemia-reperfusion (I/R injury is a pivotal clinical problem occurring in many clinical conditions such as transplantation, trauma, and hepatic failure after hemorrhagic shock. Apoptosis and autophagy have been shown to contribute to cell death in hepatic I/R injury. Ethyl pyruvate, a stable and simple lipophilic ester, has been shown to have anti-inflammatory properties. In this study, the purpose is to explore both the effect of ethyl pyruvate on hepatic I/R injury and regulation of intrinsic pathway of apoptosis and autophagy. Methods. Three doses of ethyl pyruvate (20 mg/kg, 40 mg/kg, and 80 mg/kg were administered 1 h before a model of segmental (70% hepatic warm ischemia was established in Balb/c mice. All serum and liver tissues were obtained at three different time points (4 h, 8 h, and 16 h. Results. Alanine aminotransferase (ALT, aspartate aminotransferase (AST, and pathological features were significantly ameliorated by ethyl pyruvate (80 mg/kg. The expression of Bcl-2, Bax, Beclin-1, and LC3, which play an important role in the regulation of intrinsic pathway of apoptosis and autophagy, was also obviously decreased by ethyl pyruvate (80 mg/kg. Furthermore, ethyl pyruvate inhibited the HMGB1/TLR4/ NF-κb axis and the release of cytokines (TNF-α and IL-6. Conclusion. Our results showed that ethyl pyruvate might attenuate to hepatic I/R injury by inhibiting intrinsic pathway of apoptosis and autophagy, mediated partly through downregulation of HMGB1/TLR4/ NF-κb axis and the competitive interaction with Beclin-1 of HMGB1.

  13. [Diagnostic value of detection of blood levels of lactate, pyruvate and 2,3-diphosphoglycerate in children with diabetes mellitus].

    Science.gov (United States)

    Marchenko, L F; Baturin, A A; Terent'eva, E A

    1991-01-01

    Measurements were made of lactate, pyruvate and 2,3-diphosphoglycerate in 69 children admitted to the hospital in a state of diabetic ketoacidosis of different intensity. Depending on the intensity of metabolic abnormalities, the content of lactate and pyruvate was found to be increased, whereas that of 2,3-diphosphoglycerate to be lowered. Measurements of the content of lactate and the lactate/pyruvate ratio enables carrying out differential diagnosis between the ketoacidotic and lactacidotic varieties of diabetic coma.

  14. Identificación y Caracterización de Cepas Nativas de Rhizobium en la Provincia de Santa Elena.

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    Javier Soto

    2015-10-01

    Full Text Available En los sistemas agrícolas de subsistencia, el nitrógeno es un macronutriente esencial para el buen desarrollo de las plantas; es utilizado en forma de nitrato o amonio. Las bacterias del género Rhizobium poseen la capacidad de fijar el nitrógeno, mediante una relación de simbiosis con leguminosas e influyen en la producción de sustancias promotoras de crecimiento en las plantas no leguminosas. En la península de Santa Elena no existen evidencias del uso y aplicación de biofertilizantes de origen microbiano nativo, por lo que el presente trabajo tuvo como objetivo caracterizar y seleccionar cepas del género Rhizobium procedentes de los nódulos de leguminosas de dos zonas de la provincia de Santa Elena. Los experimentos Aislamiento, identificación y caracterización bioquímica de cepas de Rhizobium encontradas en diferentes zonas de la península de Santa Elena comprende: a Estudio de la morfología nodular de leguminosas; b Presencia de la enzima Leghemoglobina en los nódulos, c Aislamiento de microorganismos de los nódulos de leguminosas, d Respuesta de la enzima catalasa ante el peróxido de hidrógeno, e Crecimiento en diferentes fuentes de carbono , f Crecimiento en tres porcentajes cloruro de sodio; y e Producción de 3-ketolactasa en agar LLA para descartar contaminantes frecuentes como Agrobacterium.

  15. Phosphate-Catalyzed Hydrogen Peroxide Formation from Agar, Gellan, and κ-Carrageenan and Recovery of Microbial Cultivability via Catalase and Pyruvate.

    Science.gov (United States)

    Kawasaki, Kosei; Kamagata, Yoichi

    2017-11-01

    Previously, we reported that when agar is autoclaved with phosphate buffer, hydrogen peroxide (H 2 O 2 ) is formed in the resulting medium (PT medium), and the colony count on the medium inoculated with environmental samples becomes much lower than that on a medium in which agar and phosphate are autoclaved separately (PS medium) (T. Tanaka et al., Appl Environ Microbiol 80:7659-7666, 2014, https://doi.org/10.1128/AEM.02741-14). However, the physicochemical mechanisms underlying this observation remain largely unknown. Here, we determined the factors affecting H 2 O 2 formation in agar. The H 2 O 2 formation was pH dependent: H 2 O 2 was formed at high concentrations in an alkaline or neutral phosphate buffer but not in an acidic buffer. Ammonium ions enhanced H 2 O 2 formation, implying the involvement of the Maillard reaction catalyzed by phosphate. We found that other gelling agents (e.g., gellan and κ-carrageenan) also produced H 2 O 2 after being autoclaved with phosphate. We then examined the cultivability of microorganisms from a fresh-water sample to test whether catalase and pyruvate, known as H 2 O 2 scavengers, are effective in yielding high colony counts. The colony count on PT medium was only 5.7% of that on PS medium. Catalase treatment effectively restored the colony count of PT medium (to 106% of that on PS medium). In contrast, pyruvate was not as effective as catalase: the colony count on sodium pyruvate-supplemented PT medium was 58% of that on PS medium. Given that both catalase and pyruvate can remove H 2 O 2 from PT medium, these observations indicate that although H 2 O 2 is the main cause of reduced colony count on PT medium, other unknown growth-inhibiting substances that cannot be removed by pyruvate (but can be by catalase) may also be involved. IMPORTANCE The majority of bacteria in natural environments are recalcitrant to laboratory culture techniques. Previously, we demonstrated that one reason for this is the formation of high H 2 O

  16. [Signaling Systems of Rhizobia (Rhizobiaceae) and Leguminous Plants (Fabaceae) upon the Formation of a Legume-Rhizobium Symbiosis (Review)].

    Science.gov (United States)

    Glyan'ko, A K

    2015-01-01

    Data from the literature and our own data on the participation and interrelation of bacterial signaling Nod-factors and components of the calcium, NADPH-oxidase, and NO-synthase signaling systems of a plant at the preinfection and infectious stages of the formation of a legume-rhizobium symbiosis are summarized in this review. The physiological role of Nod-factors, reactive oxygen species (ROS), calcium (Ca2+), NADPH-oxidase, nitric oxide (NO), and their cross influence on the processes determining the formation of symbiotic structures on the roots of the host plant is discussed.

  17. Role of O2 in the Growth of Rhizobium leguminosarum bv. viciae 3841 on Glucose and Succinate

    OpenAIRE

    Wheatley, Rachel M.; Ramachandran, Vinoy K.; Geddes, Barney A.; Perry, Benjamin J.; Yost, Chris K.; Poole, Philip S.

    2016-01-01

    Insertion sequencing (INSeq) analysis of Rhizobium leguminosarum bv. viciae 3841 (Rlv3841) grown on glucose or succinate at both 21% and 1% O2 was used to understand how O2 concentration alters metabolism. Two transcriptional regulators were required for growth on glucose (pRL120207 [eryD] and RL0547 [phoB]), five were required on succinate (pRL100388, RL1641, RL1642, RL3427, and RL4524 [ecfL]), and three were required on 1% O2 (pRL110072, RL0545 [phoU], and RL4042). A novel toxin-antitoxin s...

  18. Induction of fungal disease resistance in Vicia faba by dual inoculation with Rhizobium leguminosarum and vesicular-arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Rabie, G H

    1998-01-01

    Infection of Vicia faba with Bothytis fabae causes significant decreases in growth vigour, total nitrogen content, number of nodules and nutrient accumulation. Na-uptake and phenolics concentration increased compared to that of noninfected plants. In contrast, dual inoculation of Rhizobium and VA mycorrhizae increased all above parameters suggesting a distinct improvement of the plants. The results also revealed that an inverse correlation may exist between phenolic, calcium, magnesium and zinc concentrations in mycorrhizal plant tissues grown in presence of rhizobial bacteria and the disease severity. From these findings we conclude a possible role of both VA mycorrhizal fungi and rhizobial bacteria in the decrease of susceptibility of plants.

  19. Chronic pyruvate supplementation increases exploratory activity and brain energy reserves in young and middle-aged mice

    DEFF Research Database (Denmark)

    Koivisto, Hennariikka; Leinonen, Henri; Puurula, Mari

    2016-01-01

    to brain and thereby attenuate aging- or AD-related cognitive impairment. Mice received ~800 mg/kg/day Na-pyruvate in their chow for 2-6 months. In middle-aged wild-type mice and in 6.5-month-old APP/PS1 mice, pyruvate facilitated spatial learning and increased exploration of a novel odor. However......, in passive avoidance task for fear memory, the treatment group was clearly impaired. Independent of age, long-term pyruvate increased explorative behavior, which likely explains the paradoxical impairment in passive avoidance. We also assessed pyruvate effects on body weight, muscle force, and endurance...

  20. Improvement of Faba Bean Yield Using Rhizobium/Agrobacterium Inoculant in Low-Fertility Sandy Soil

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    Sameh H. Youseif

    2017-01-01

    Full Text Available Soil fertility is one of the major limiting factors for crop’s productivity in Egypt and the world in general. Biological nitrogen fixation (BNF has a great importance as a non-polluting and a cost-effective way to improve soil fertility through supplying N to different agricultural systems. Faba bean (Vicia faba L. is one of the most efficient nitrogen-fixing legumes that can meet all of their N needs through BNF. Therefore, understanding the impact of rhizobial inoculation and contrasting soil rhizobia on nodulation and N2 fixation in faba bean is crucial to optimize the crop yield, particularly under low fertility soil conditions. This study investigated the symbiotic effectiveness of 17 Rhizobium/Agrobacterium strains previously isolated from different Egyptian governorates in improving the nodulation and N2 fixation in faba bean cv. Giza 843 under controlled greenhouse conditions. Five strains that had a high nitrogen-fixing capacity under greenhouse conditions were subsequently tested in field trials as faba bean inoculants at Ismaillia Governorate in northeast Egypt in comparison with the chemical N-fertilization treatment (96 kg N·ha−1. A starter N-dose (48 kg N·ha−1 was applied in combination with different Rhizobium inoculants. The field experiments were established at sites without a background of inoculation under low fertility sandy soil conditions over two successive winter growing seasons, 2012/2013 and 2013/2014. Under greenhouse conditions, inoculated plants produced significantly higher nodules dry weight, plant biomass, and shoot N-uptake than non-inoculated ones. In the first season (2012/2013, inoculation of field-grown faba bean showed significant improvements in seed yield (3.73–4.36 ton·ha−1 and seed N-yield (138–153 Kg N·ha−1, which were higher than the uninoculated control (48 kg N·ha−1 that produced 2.97 Kg·ha−1 and 95 kg N·ha−1, respectively. Similarly, in the second season (2013

  1. Metabolic responses to pyruvate kinase deletion in lysine producing Corynebacterium glutamicum

    Directory of Open Access Journals (Sweden)

    Wittmann Christoph

    2008-03-01

    Full Text Available Abstract Background Pyruvate kinase is an important element in flux control of the intermediate metabolism. It catalyzes the irreversible conversion of phosphoenolpyruvate into pyruvate and is under allosteric control. In Corynebacterium glutamicum, this enzyme was regarded as promising target for improved production of lysine, one of the major amino acids in animal nutrition. In pyruvate kinase deficient strains the required equimolar ratio of the two lysine precursors oxaloacetate and pyruvate can be achieved through concerted action of the phosphotransferase system (PTS and phosphoenolpyruvate carboxylase (PEPC, whereby a reduced amount of carbon may be lost as CO2 due to reduced flux into the tricarboxylic acid (TCA cycle. In previous studies, deletion of pyruvate kinase in lysine-producing C. glutamicum, however, did not yield a clear picture and the exact metabolic consequences are not fully understood. Results In this work, deletion of the pyk gene, encoding pyruvate kinase, was carried out in the lysine-producing strain C. glutamicum lysCfbr, expressing a feedback resistant aspartokinase, to investigate the cellular response to deletion of this central glycolytic enzyme. Pyk deletion was achieved by allelic replacement, verified by PCR analysis and the lack of in vitro enzyme activity. The deletion mutant showed an overall growth behavior (specific growth rate, glucose uptake rate, biomass yield which was very similar to that of the parent strain, but differed in slightly reduced lysine formation, increased formation of the overflow metabolites dihydroxyacetone and glycerol and in metabolic fluxes around the pyruvate node. The latter involved a flux shift from pyruvate carboxylase (PC to PEPC, by which the cell maintained anaplerotic supply of the TCA cycle. This created a metabolic by-pass from PEP to pyruvate via malic enzyme demonstrating its contribution to metabolic flexibility of C. glutamicum on glucose. Conclusion The metabolic

  2. Phosphorylation status of pyruvate dehydrogenase distinguishes metabolic phenotypes of cultured rat brain astrocytes and neurons.

    Science.gov (United States)

    Halim, Nader D; Mcfate, Thomas; Mohyeldin, Ahmed; Okagaki, Peter; Korotchkina, Lioubov G; Patel, Mulchand S; Jeoung, Nam Ho; Harris, Robert A; Schell, Michael J; Verma, Ajay

    2010-08-01

    Glucose metabolism in nervous tissue has been proposed to occur in a compartmentalized manner with astrocytes contributing largely to glycolysis and neurons being the primary site of glucose oxidation. However, mammalian astrocytes and neurons both contain mitochondria, and it remains unclear why in culture neurons oxidize glucose, lactate, and pyruvate to a much larger extent than astrocytes. The objective of this study was to determine whether pyruvate metabolism is differentially regulated in cultured neurons versus astrocytes. Expression of all components of the pyruvate dehydrogenase complex (PDC), the rate-limiting step for pyruvate entry into the Krebs cycle, was determined in cultured astrocytes and neurons. In addition, regulation of PDC enzymatic activity in the two cell types via protein phosphorylation was examined. We show that all components of the PDC are expressed in both cell types in culture, but that PDC activity is kept strongly inhibited in astrocytes through phosphorylation of the pyruvate dehydrogenase alpha subunit (PDH alpha). In contrast, neuronal PDC operates close to maximal levels with much lower levels of phosphorylated PDH alpha. Dephosphorylation of astrocytic PDH alpha restores PDC activity and lowers lactate production. Our findings suggest that the glucose metabolism of astrocytes and neurons may be far more flexible than previously believed. (c) 2010 Wiley-Liss, Inc.

  3. An ancestral role for the mitochondrial pyruvate carrier in glucose-stimulated insulin secretion

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    Kyle S. McCommis

    2016-08-01

    Full Text Available Objective: Transport of pyruvate into the mitochondrial matrix by the Mitochondrial Pyruvate Carrier (MPC is an important and rate-limiting step in its metabolism. In pancreatic β-cells, mitochondrial pyruvate metabolism is thought to be important for glucose sensing and glucose-stimulated insulin secretion. Methods: To evaluate the role that the MPC plays in maintaining systemic glucose homeostasis, we used genetically-engineered Drosophila and mice with loss of MPC activity in insulin-producing cells. Results: In both species, MPC deficiency results in elevated blood sugar concentrations and glucose intolerance accompanied by impaired glucose-stimulated insulin secretion. In mouse islets, β-cell MPC-deficiency resulted in decreased respiration with glucose, ATP-sensitive potassium (KATP channel hyperactivity, and impaired insulin release. Moreover, treatment of pancreas-specific MPC knockout mice with glibenclamide, a sulfonylurea KATP channel inhibitor, improved defects in islet insulin secretion and abnormalities in glucose homeostasis in vivo. Finally, using a recently-developed biosensor for MPC activity, we show that the MPC is rapidly stimulated by glucose treatment in INS-1 insulinoma cells suggesting that glucose sensing is coupled to mitochondrial pyruvate carrier activity. Conclusions: Altogether, these studies suggest that the MPC plays an important and ancestral role in insulin-secreting cells in mediating glucose sensing, regulating insulin secretion, and controlling systemic glycemia. Keywords: Stimulus-coupled secretion, Insulin, β-Cell, Diabetes, Pyruvate, Mitochondria, Drosophila

  4. The mitochondrial pyruvate carrier mediates high fat diet-induced increases in hepatic TCA cycle capacity.

    Science.gov (United States)

    Rauckhorst, Adam J; Gray, Lawrence R; Sheldon, Ryan D; Fu, Xiaorong; Pewa, Alvin D; Feddersen, Charlotte R; Dupuy, Adam J; Gibson-Corley, Katherine N; Cox, James E; Burgess, Shawn C; Taylor, Eric B

    2017-11-01

    Excessive hepatic gluconeogenesis is a defining feature of type 2 diabetes (T2D). Most gluconeogenic flux is routed through mitochondria. The mitochondrial pyruvate carrier (MPC) transports pyruvate from the cytosol into the mitochondrial matrix, thereby gating pyruvate-driven gluconeogenesis. Disruption of the hepatocyte MPC attenuates hyperglycemia in mice during high fat diet (HFD)-induced obesity but exerts minimal effects on glycemia in normal chow diet (NCD)-fed conditions. The goal of this investigation was to test whether hepatocyte MPC disruption provides sustained protection from hyperglycemia during long-term HFD and the differential effects of hepatocyte MPC disruption on TCA cycle metabolism in NCD versus HFD conditions. We utilized long-term high fat feeding, serial measurements of postabsorptive blood glucose and metabolomic profiling and 13 C-lactate/ 13 C-pyruvate tracing to investigate the contribution of the MPC to hyperglycemia and altered hepatic TCA cycle metabolism during HFD-induced obesity. Hepatocyte MPC disruption resulted in long-term attenuation of hyperglycemia induced by HFD. HFD increased hepatic mitochondrial pyruvate utilization and TCA cycle capacity in an MPC-dependent manner. Furthermore, MPC disruption decreased progression of fibrosis and levels of transcript markers of inflammation. By contributing to chronic hyperglycemia, fibrosis, and TCA cycle expansion, the hepatocyte MPC is a key mediator of the pathophysiology induced in the HFD model of T2D. Copyright © 2017 The Authors. Published by Elsevier GmbH.. All rights reserved.

  5. A new synthesis of [3-11C]pyruvic acid using alanine racemase

    International Nuclear Information System (INIS)

    Ikemoto, M.; Okamoto, E.; Sasaki, M.; Haradahira, T.; Omura, H.; Furuya, Y.; Suzuki, K.; Watanabe, Y.

    1998-01-01

    The synthesis of [3- 11 C]pyruvic acid was attempted by two reaction systems (A: alanine racemase and D-amino acid oxidase, B: alanine racemase and L-alanine dehydrogenase) utilizing a new thermostable enzyme, alanine racemase. Conversion rates from D,L-[3- 11 C]alanine to [3- 11 C]pyruvic acid were almost 100% in both methods. Similar results were obtained with immobilized enzymes packed in a single column. Furthermore, the same column could be used repeatedly without a remarkable decrease of the [3- 11 C]pyruvic acid yield. Various matrices were tested for the immobilizing enzyme, and Aminopropyl-CPG was concluded to be the most suitable since the loss of the enzyme activity was the least in the studied matrices

  6. Inactivation of pyruvate dehydrogenase kinase 2 by mitochondrial reactive oxygen species.

    Science.gov (United States)

    Hurd, Thomas R; Collins, Yvonne; Abakumova, Irina; Chouchani, Edward T; Baranowski, Bartlomiej; Fearnley, Ian M; Prime, Tracy A; Murphy, Michael P; James, Andrew M

    2012-10-12

    Reactive oxygen species are byproducts of mitochondrial respiration and thus potential regulators of mitochondrial function. Pyruvate dehydrogenase kinase 2 (PDHK2) inhibits the pyruvate dehydrogenase complex, thereby regulating entry of carbohydrates into the tricarboxylic acid (TCA) cycle. Here we show that PDHK2 activity is inhibited by low levels of hydrogen peroxide (H(2)O(2)) generated by the respiratory chain. This occurs via reversible oxidation of cysteine residues 45 and 392 on PDHK2 and results in increased pyruvate dehydrogenase complex activity. H(2)O(2) derives from superoxide (O(2)(.)), and we show that conditions that inhibit PDHK2 also inactivate the TCA cycle enzyme, aconitase. These findings suggest that under conditions of high mitochondrial O(2)(.) production, such as may occur under nutrient excess and low ATP demand, the increase in O(2)() and H(2)O(2) may provide feedback signals to modulate mitochondrial metabolism.

  7. Effect of Rhizobium and Phosphate Solubilizing Bacterial Inoculants on Symbiotic Traits, Nodule Leghemoglobin, and Yield of Chickpea Genotypes

    Directory of Open Access Journals (Sweden)

    G. S. Tagore

    2013-01-01

    Full Text Available A field experiment was carried out during the rabi season of 2004-05 to find out the effect of Rhizobium and phosphate solubilizing bacterial (PSB inoculants on symbiotic traits, nodule leghemoglobin, and yield of five elite genotypes of chickpea. Among the chickpea genotypes, IG-593 performed better in respect of symbiotic parameters including nodule number, nodule fresh weight, nodule dry weight, shoot dry weight, yield attributes and yield. Leghemoglobin content (2.55 mg g−1 of fresh nodule was also higher under IG-593. Among microbial inoculants, the Rhizobium + PSB was found most effective in terms of nodule number (27.66 nodules plant−1, nodule fresh weight (144.90 mg plant−1, nodule dry weight (74.30 mg plant−1, shoot dry weight (11.76 g plant−1, and leghemoglobin content (2.29 mg g−1 of fresh nodule and also showed its positive effect in enhancing all the yield attributing parameters, grain and straw yields.

  8. Improvement of Canola (Brassica napus L.) Inoculated with Rhizobium, Azospirillum and/or Mycorrhizal Fungi Under Salinity Stress

    International Nuclear Information System (INIS)

    El-Ghandour, I. A.; Galal, Y.G; Ebraheem, Rabab M.M.; Yousef, Khayria A.

    2004-01-01

    Bio fertilization technology was applied for improving canola plant growth and nutrient acquisition in sandy saline soil ,as a biological mean used to develop plant growth and nutrient uptake under salinity stress. Canola was cultivated in pots packed at rate of 7 kg saline sandy soil pot -1 , and inoculated with Rhizobium leguminosarum biovar viceae, Azospirillum brasilense strain no. 40 and arbuscular mycorrhizal fungi either solely or in combinations of them. Nitrogen fertilizer was added in form ( 15 NH 4 ) 2 SO 4 with 5% 15 N atom excess at rate of 0.99 g N pot -1 . Maximum dry matter accumulation induced by composite inoculation (Rh + Azo + AM). Na concentrations were frequently affected by Rhizobium and /or mycorrhizae while K was affected by Azospirillum and /or mycorrhizae. Azospirillum enhanced Ca uptake whereas Mg content was responded well to composite inoculants of Rh + Azo + AM. Dual inoculation with Rh + Azo resulted in the highest values of N uptake by plant. Similar effect was noticed with P uptake when dual inoculums of Azo + AM were applied. Data of 15 N isotope showed that the highest portion and value of N 2 -fixed was recorded with composite inoculums followed by dual inoculations. On the other hand, the infection with AM fungi gave the highest proportion of N derived from fertilizer as compared to other inoculants or uninoculated control. In the same trend, the fertilizer use efficiency (FUE%) was enhanced by AM infection. Dual inoculums of Rh + Azo induced highest content of proline in leaves. (Authors)

  9. Homology of genes for exopolysaccharide synthesis in Rhizobium leguminosarum and effect of cloned exo genes on nodule formation

    International Nuclear Information System (INIS)

    Skorupska, A.; Derylo, M.

    1993-01-01

    A 5.4 kb BamHI fragment of Rhizobium leguminosarum (R.l.) bv. trifolii TA1 was found to carry genes involved in exopolysaccharide synthesis (exo genes). This fragment was strongly hybridized to the total DNA from DNA from R.l. bv. viciae and bv. phaseoli digested with EcoRI. No homology was found with total DNA of R. melilotic and Rhizobium sp. NGR 234. The exo genes R.l. bv. trifolii TA1 conjugally introduced into R.l. bv. viciae 1302 considerably affected the symbiosis: the nodules induced on vetch were abortive and did not fix nitrogen. On the other hand, Phaseolus beans infected with R.l. bv. trifolii exo genes formed the nitrogen-fixing nodules. It can be conduced that additional copies of exo genes introduced into wild type R.l. strains can disturb the synthesis of acidic exopolysaccharides and affect symbiosis of the plants forming indeterminate nodules, but do not affect symbiosis of the plants forming the determinate nodules. (author). 29 refs, 2 figs, 2 tabs

  10. Metabolic Imaging of Patients with Prostate Cancer Using Hyperpolarized [1-13C]Pyruvate

    Science.gov (United States)

    Nelson, Sarah J.; Kurhanewicz, John; Vigneron, Daniel B.; Larson, Peder E. Z.; Harzstark, Andrea L.; Ferrone, Marcus; van Criekinge, Mark; Chang, Jose W.; Bok, Robert; Park, Ilwoo; Reed, Galen; Carvajal, Lucas; Small, Eric J.; Munster, Pamela; Weinberg, Vivian K.; Ardenkjaer-Larsen, Jan Henrik; Chen, Albert P.; Hurd, Ralph E.; Odegardstuen, Liv-Ingrid; Robb, Fraser J.; Tropp, James; Murray, Jonathan A.

    2014-01-01

    This first-in-man imaging study evaluated the safety and feasibility of hyperpolarized [1-13C]pyruvate as an agent for noninvasively characterizing alterations in tumor metabolism for patients with prostate cancer. Imaging living systems with hyperpolarized agents can result in more than 10,000-fold enhancement in signal relative to conventional magnetic resonance (MR) imaging. When combined with the rapid acquisition of in vivo 13C MR data, it is possible to evaluate the distribution of agents such as [1-13C]pyruvate and its metabolic products lactate, alanine, and bicarbonate in a matter of seconds. Preclinical studies in cancer models have detected elevated levels of hyperpolarized [1-13C]lactate in tumor, with the ratio of [1-13C]lactate/[1-13C]pyruvate being increased in high-grade tumors and decreased after successful treatment. Translation of this technology into humans was achieved by modifying the instrument that generates the hyperpolarized agent, constructing specialized radio frequency coils to detect 13C nuclei, and developing new pulse sequences to efficiently capture the signal. The study population comprised patients with biopsy-proven prostate cancer, with 31 subjects being injected with hyperpolarized [1-13C]pyruvate. The median time to deliver the agent was 66 s, and uptake was observed about 20 s after injection. No dose-limiting toxicities were observed, and the highest dose (0.43 ml/kg of 230 mM agent) gave the best signal-to-noise ratio for hyperpolarized [1-13C]pyruvate. The results were extremely promising in not only confirming the safety of the agent but also showing elevated [1-13C]lactate/[1-13C]pyruvate in regions of biopsy-proven cancer. These findings will be valuable for noninvasive cancer diagnosis and treatment monitoring in future clinical trials. PMID:23946197

  11. Pyruvate administration reduces recurrent/moderate hypoglycemia-induced cortical neuron death in diabetic rats.

    Directory of Open Access Journals (Sweden)

    Bo Young Choi

    Full Text Available Recurrent/moderate (R/M hypoglycemia is common in type 1 diabetes patients. Moderate hypoglycemia is not life-threatening, but if experienced recurrently it may present several clinical complications. Activated PARP-1 consumes cytosolic NAD, and because NAD is required for glycolysis, hypoglycemia-induced PARP-1 activation may render cells unable to use glucose even when glucose availability is restored. Pyruvate, however, can be metabolized in the absence of cytosolic NAD. We therefore hypothesized that pyruvate may be able to improve the outcome in diabetic rats subjected to insulin-induced R/M hypoglycemia by terminating hypoglycemia with glucose plus pyruvate, as compared with delivering just glucose alone. In an effort to mimic juvenile type 1 diabetes the experiments were conducted in one-month-old young rats that were rendered diabetic by streptozotocin (STZ, 50mg/kg, i.p. injection. One week after STZ injection, rats were subjected to moderate hypoglycemia by insulin injection (10 U/kg, i.p. without anesthesia for five consecutive days. Pyruvate (500 mg/kg was given by intraperitoneal injection after each R/M hypoglycemia. Three hours after last R/M hypoglycemia, zinc accumulation was evaluated. Three days after R/M hypoglycemia, neuronal death, oxidative stress, microglial activation and GSH concentrations in the cerebral cortex were analyzed. Sparse neuronal death was observed in the cortex. Zinc accumulation, oxidative injury, microglial activation and GSH loss in the cortex after R/M hypoglycemia were all reduced by pyruvate injection. These findings suggest that when delivered alongside glucose, pyruvate may significantly improve the outcome after R/M hypoglycemia by circumventing a sustained impairment in neuronal glucose utilization resulting from PARP-1 activation.

  12. Competitive nodulation blocking of cv. Afghanistan pea is related to high levels of nodulation factors made by some strains of Rhizobium leguminosarum bv. viciae

    NARCIS (Netherlands)

    Hogg, B.; Davies, A.E.; Wilson, K.E.; Bisseling, T.; Downie, J.A.

    2002-01-01

    Cultivar Afghanistan peas are resistant to nodulation by many strains of Rhizobium leguminosarum bv. viciae but are nodulated by strain TOM, which carries the host specificity gene nodX. Some strains that lack nodX can inhibit nodulation of cv. Afghanistan by strain TOM. We present evidence that

  13. The ethylene-inhibitor aminoethoxyvinylglycine restores normal nodulation by Rhizobium leguminosarum biovar. viciae on Vicia sativa subsp. nigra by suppressing the 'Thick and short roots' phenotype

    NARCIS (Netherlands)

    Zaat, S. A.; van Brussel, A. A.; Tak, T.; Lugtenberg, B. J.; KIJNE, J. W.

    1989-01-01

    Nodulation of Vicia sativa subsp. nigra L. by Rhizobium bacteria is coupled to the development of thick and short roots (Tsr). This root phenotype as well as root-hair induction (Hai) and root-hair deformation (Had) are caused by a factor(s) produced by the bacteria in response to plant flavonoids.

  14. Improved purification, crystallization and primary structure of pyruvate:ferredoxin oxidoreductase from Halobacterium halobium.

    Science.gov (United States)

    Plaga, W; Lottspeich, F; Oesterhelt, D

    1992-04-01

    An improved purification procedure, including nickel chelate affinity chromatography, is reported which resulted in a crystallizable pyruvate:ferredoxin oxidoreductase preparation from Halobacterium halobium. Crystals of the enzyme were obtained using potassium citrate as the precipitant. The genes coding for pyruvate:ferredoxin oxidoreductase were cloned and their nucleotide sequences determined. The genes of both subunits were adjacent to one another on the halobacterial genome. The derived amino acid sequences were confirmed by partial primary structure analysis of the purified protein. The structural motif of thiamin-diphosphate-binding enzymes was unequivocally located in the deduced amino acid sequence of the small subunit.

  15. Pyruvate sensitizes pancreatic tumors to hypoxia-activated prodrug TH-302.

    Science.gov (United States)

    Wojtkowiak, Jonathan W; Cornnell, Heather C; Matsumoto, Shingo; Saito, Keita; Takakusagi, Yoichi; Dutta, Prasanta; Kim, Munju; Zhang, Xiaomeng; Leos, Rafael; Bailey, Kate M; Martinez, Gary; Lloyd, Mark C; Weber, Craig; Mitchell, James B; Lynch, Ronald M; Baker, Amanda F; Gatenby, Robert A; Rejniak, Katarzyna A; Hart, Charles; Krishna, Murali C; Gillies, Robert J

    2015-01-01

    Hypoxic niches in solid tumors harbor therapy-resistant cells. Hypoxia-activated prodrugs (HAPs) have been designed to overcome this resistance and, to date, have begun to show clinical efficacy. However, clinical HAPs activity could be improved. In this study, we sought to identify non-pharmacological methods to acutely exacerbate tumor hypoxia to increase TH-302 activity in pancreatic ductal adenocarcinoma (PDAC) tumor models. Three human PDAC cell lines with varying sensitivity to TH-302 (Hs766t > MiaPaCa-2 > SU.86.86) were used to establish PDAC xenograft models. PDAC cells were metabolically profiled in vitro and in vivo using the Seahorse XF system and hyperpolarized (13)C pyruvate MRI, respectively, in addition to quantitative immunohistochemistry. The effect of exogenous pyruvate on tumor oxygenation was determined using electroparamagnetic resonance (EPR) oxygen imaging. Hs766t and MiaPaCa-2 cells exhibited a glycolytic phenotype in comparison to TH-302 resistant line SU.86.86. Supporting this observation is a higher lactate/pyruvate ratio in Hs766t and MiaPaCa xenografts as observed during hyperpolarized pyruvate MRI studies in vivo. Coincidentally, response to exogenous pyruvate both in vitro (Seahorse oxygen consumption) and in vivo (EPR oxygen imaging) was greatest in Hs766t and MiaPaCa models, possibly due to a higher mitochondrial reserve capacity. Changes in oxygen consumption and in vivo hypoxic status to pyruvate were limited in the SU.86.86 model. Combination therapy of pyruvate plus TH-302 in vivo significantly decreased tumor growth and increased survival in the MiaPaCa model and improved survival in Hs766t tumors. Using metabolic profiling, functional imaging, and computational modeling, we show improved TH-302 activity by transiently increasing tumor hypoxia metabolically with exogenous pyruvate. Additionally, this work identified a set of biomarkers that may be used clinically to predict which tumors will be most responsive to

  16. The moonlighting function of pyruvate carboxylase resides in the non-catalytic end of the TIM barrel

    NARCIS (Netherlands)

    Huberts, Daphne H. E. W.; Venselaar, Hanka; Vriend, Gert; Veenhuis, Marten; van der Klei, Ida J.

    Pyruvate carboxylase is a highly conserved enzyme that functions in replenishing the tricarboxylic acid cycle with oxaloacetate. In the yeast Hansenula polymorpha, the pyruvate carboxylase protein is also required for import and assembly of the peroxisomal enzyme alcohol oxidase. This additional

  17. Chronic pyruvate supplementation increases exploratory activity and brain energy reserves in young and middle-aged mice

    Directory of Open Access Journals (Sweden)

    Hennariikka eKoivisto

    2016-03-01

    Full Text Available Numerous studies have reported neuroprotective effects of pyruvate when given in systemic injections. Impaired glucose uptake and metabolism are found in Alzheimer's disease (AD and in AD mouse models. We tested whether dietary pyruvate supplementation is able to provide added energy supply to brain and thereby attenuate aging- or AD-related cognitive impairment. Mice received ~ 800 mg/kg/day Na-pyruvate in their chow for 2- 6 months. In middle-aged wild-type mice and in 6.5-month-old APP/PS1 mice, pyruvate facilitated spatial learning and increased exploration of a novel odor. However, in passive avoidance task for fear memory, the treatment group was clearly impaired. Independent of age, long-term pyruvate increased explorative behavior, which likely explains the paradoxical impairment in passive avoidance. We also assessed pyruvate effects on body weight, muscle force and endurance, and found no effects. Metabolic post-mortem assays revealed increased energy compounds in nuclear magnetic resonance spectroscopy as well as increased brain glycogen storages in the pyruvate group. Pyruvate supplementation may counteract aging-related behavioral impairment but its beneficial effect seems related to increased explorative activity rather than direct memory enhancement.

  18. Exo-oligosaccharides of Rhizobium sp. strain NGR234 are required for symbiosis with various legumes.

    Science.gov (United States)

    Staehelin, Christian; Forsberg, Lennart S; D'Haeze, Wim; Gao, Mu-Yun; Carlson, Russell W; Xie, Zhi-Ping; Pellock, Brett J; Jones, Kathryn M; Walker, Graham C; Streit, Wolfgang R; Broughton, William J

    2006-09-01

    Rhizobia are nitrogen-fixing bacteria that establish endosymbiotic associations with legumes. Nodule formation depends on various bacterial carbohydrates, including lipopolysaccharides, K-antigens, and exopolysaccharides (EPS). An acidic EPS from Rhizobium sp. strain NGR234 consists of glucosyl (Glc), galactosyl (Gal), glucuronosyl (GlcA), and 4,6-pyruvylated galactosyl (PvGal) residues with beta-1,3, beta-1,4, beta-1,6, alpha-1,3, and alpha-1,4 glycoside linkages. Here we examined the role of NGR234 genes in the synthesis of EPS. Deletions within the exoF, exoL, exoP, exoQ, and exoY genes suppressed accumulation of EPS in bacterial supernatants, a finding that was confirmed by chemical analyses. The data suggest that the repeating subunits of EPS are assembled by an ExoQ/ExoP/ExoF-dependent mechanism, which is related to the Wzy polymerization system of group 1 capsular polysaccharides in Escherichia coli. Mutation of exoK (NGROmegaexoK), which encodes a putative glycanase, resulted in the absence of low-molecular-weight forms of EPS. Analysis of the extracellular carbohydrates revealed that NGROmegaexoK is unable to accumulate exo-oligosaccharides (EOSs), which are O-acetylated nonasaccharide subunits of EPS having the formula Gal(Glc)5(GlcA)2PvGal. When used as inoculants, both the exo-deficient mutants and NGROmegaexoK were unable to form nitrogen-fixing nodules on some hosts (e.g., Albizia lebbeck and Leucaena leucocephala), but they were able to form nitrogen-fixing nodules on other hosts (e.g., Vigna unguiculata). EOSs of the parent strain were biologically active at very low levels (yield in culture supernatants, approximately 50 microg per liter). Thus, NGR234 produces symbiotically active EOSs by enzymatic degradation of EPS, using the extracellular endo-beta-1,4-glycanase encoded by exoK (glycoside hydrolase family 16). We propose that the derived EOSs (and not EPS) are bacterial components that play a crucial role in nodule formation in various legumes.

  19. Intensity of Ground Cover Crop Arachis pintoi, Rhizobium Inoculation and Phosphorus Application and Their Effects on Field Growth and Nutrient Status of Cocoa Plants

    Directory of Open Access Journals (Sweden)

    John Bako Baon

    2006-08-01

    Full Text Available Arachis pintoiis potentially as a cover crop for cocoa (Theobroma cacaoL. farm, however information regarding its effect on the growth of cocoa plants in the field is very limited. The objective of this experiment is to investigate the combined influence of ground cover crop A. pintoi, rhizobial bacterial inoculation and phosphorus (P fertilizer on the growth of cocoa in the field and nutrient status. This experiment laid out in split-split plot design consisted of three levels of cover crop (without, A. pintoiand Calopogonium caeruleum, two levels of rhizobium inoculation (not inoculated and inoculated and two levels of phosphorus application (no P added and P added. The results showed that in field condition the presence of A. pintoias cover crop did not affect the growth of cocoa. On the other hand, C. caeruleumas cover crop tended to restrict cocoa growth compared to A. pintoi. Application of P increased leaf number of cocoa plant. Biomass production of A. pintoiwas 40% higher than C. caeruleum. Soil organic carbon and nitrogen contents were not affected by ground cover crops, though higher value (0.235% N and 1.63% organic C was obtained from combined treatments of inoculation and P addition or neither inoculation nor P addition. In the case of no rhizobium inoculation, soil N content in cocoa farm with A. pintoicover crop was lower than that of without cover crop or with C. caeruleum. Cover crop increased plant N content when there was no inoculation, on the other hand rhizobium inoculation decreased N content of cocoa tissue. Tissue P content of cocoa plant was not influenced by A. Pintoicover crop or by rhizobium inoculation, except that the P tissue content of cocoa was 28% higher when the cover crop was C. caeruleumand inoculated. Key words : Arachis pintoi, Theobroma cacao, Calopogonium caeruleum, rhizobium, nitrogen, phosphorus.

  20. Et hjem

    DEFF Research Database (Denmark)

    Bruun, Maja Hojer

    2014-01-01

    Når folk sætter deres hjem til salg - især når der hersker usikkerhed om værdier og priser som under de seneste års boligkrise - får det os til at tænke over, hvad vilkårene er for at stifte, skabe og genskabe hjem i et moderne markedsbaseret samfund: Den integrerede helhed af personer, ting og...... sted, som hjemmet udgør i hverdagslivet, opløses, når et hjem sættes til salg og gøres til en vare på et boligmarked. Til hjemmets potentiale som vare knytter der sig drømme og forventninger til fremtiden - og i krisetider utryghed og uhygge....

  1. Growth hormone-induced insulin resistance in human subjects involves reduced pyruvate dehydrogenase activity

    DEFF Research Database (Denmark)

    Nellemann, B.; Vendelbo, M.H.; Nielsen, Thomas Svava

    2014-01-01

    Insulin resistance induced by growth hormone (GH) is linked to promotion of lipolysis by unknown mechanisms. We hypothesized that suppression of the activity of pyruvate dehydrogenase in the active form (PDHa) underlies GH-induced insulin resistance similar to what is observed during fasting....

  2. Multi site Kinetic Modeling of 13C Metabolic MR Using [1-13C]Pyruvate

    International Nuclear Information System (INIS)

    Damian, P.A.G.; Sperl, J.I.; Janich, M.A.; Wiesinger, F.; Schulte, R.F.; Menzel, M.I.; Damian, P.A.G.; Damian, P.A.G.; Haase, A.; Janich, M.A.; Schwaiger, M.; Janich, M.A.; Khegai, O.; Glaser, S.J.

    2014-01-01

    Hyperpolarized 13 C imaging allows real-time in vivo measurements of metabolite levels. Quantification of metabolite conversion between [1- 13 C]pyruvate and downstream metabolites [1- 13 C]alanine, [1- 13 C]lactate, and [ 13 C] bicarbonate can be achieved through kinetic modeling. Since pyruvate interacts dynamically and simultaneously with its downstream metabolites, the purpose of this work is the determination of parameter values through a multi site, dynamic model involving possible biochemical pathways present in MR spectroscopy. Kinetic modeling parameters were determined by fitting the multi site model to time-domain dynamic metabolite data. The results for different pyruvate doses were compared with those of different two-site models to evaluate the hypothesis that for identical data the uncertainty of a model and the signal-to-noise ratio determine the sensitivity in detecting small physiological differences in the target metabolism. In comparison to the two-site exchange models, the multi site model yielded metabolic conversion rates with smaller bias and smaller standard deviation, as demonstrated in simulations with different signal-to-noise ratio. Pyruvate dose effects observed previously were confirmed and quantified through metabolic conversion rate values. Parameter interdependency allowed an accurate quantification and can therefore be useful for monitoring metabolic activity in different tissues

  3. Dissociative electron attachment and anion-induced dimerization in pyruvic acid

    Czech Academy of Sciences Publication Activity Database

    Zawadzki, Mateusz; Ranković, Miloš; Kočišek, Jaroslav; Fedor, Juraj

    2018-01-01

    Roč. 20, č. 10 (2018), s. 6838-6844 ISSN 1463-9076 R&D Projects: GA ČR GA17-04844S; GA ČR GJ16-10995Y Institutional support: RVO:61388955 Keywords : pyruvic acid * electron attachment * dimerization Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 4.123, year: 2016

  4. Mitochondrial metabolism of pyruvate is essential for regulating glucose-stimulated insulin secretion.

    Science.gov (United States)

    Patterson, Jessica N; Cousteils, Katelyn; Lou, Jennifer W; Manning Fox, Jocelyn E; MacDonald, Patrick E; Joseph, Jamie W

    2014-05-09

    It is well known that mitochondrial metabolism of pyruvate is critical for insulin secretion; however, we know little about how pyruvate is transported into mitochondria in β-cells. Part of the reason for this lack of knowledge is that the carrier gene was only discovered in 2012. In the current study, we assess the role of the recently identified carrier in the regulation of insulin secretion. Our studies show that β-cells express both mitochondrial pyruvate carriers (Mpc1 and Mpc2). Using both pharmacological inhibitors and siRNA-mediated knockdown of the MPCs we show that this carrier plays a key role in regulating insulin secretion in clonal 832/13 β-cells as well as rat and human islets. We also show that the MPC is an essential regulator of both the ATP-regulated potassium (KATP) channel-dependent and -independent pathways of insulin secretion. Inhibition of the MPC blocks the glucose-stimulated increase in two key signaling molecules involved in regulating insulin secretion, the ATP/ADP ratio and NADPH/NADP(+) ratio. The MPC also plays a role in in vivo glucose homeostasis as inhibition of MPC by the pharmacological inhibitor α-cyano-β-(1-phenylindol-3-yl)-acrylate (UK5099) resulted in impaired glucose tolerance. These studies clearly show that the newly identified mitochondrial pyruvate carrier sits at an important branching point in nutrient metabolism and that it is an essential regulator of insulin secretion.

  5. Magnetic resonance and fluorescence studies on pyruvate dehydrogenase complexes and their small molecular weight constituents

    NARCIS (Netherlands)

    Grande, H.J.

    1976-01-01

    The articles presented in this thesis do not describe at first glance one well-defined subject. They are, however, in fact connected by one central theme: the study of large enzyme aggregates by molecular physical methods. Chosen was the pyruvate dehydrogenase complex (PDC) because of its

  6. Pyruvate Oxidase Influences the Sugar Utilization Pattern and Capsule Production in Streptococcus pneumoniae

    NARCIS (Netherlands)

    Carvalho, Sandra M.; Farshchi Andisi, Vahid; Gradstedt, Henrik; Neef, Jolanda; Kuipers, Oscar P.; Neves, Ana R.; Bijlsma, Jetta J. E.

    2013-01-01

    Pyruvate oxidase is a key function in the metabolism and lifestyle of many lactic acid bacteria and its activity depends on the presence of environmental oxygen. In Streptococcus pneumoniae the protein has been suggested to play a major role in metabolism and has been implicated in virulence,

  7. Multisite Kinetic Modeling of 13C Metabolic MR Using [1-13C]Pyruvate

    Directory of Open Access Journals (Sweden)

    Pedro A. Gómez Damián

    2014-01-01

    Full Text Available Hyperpolarized 13C imaging allows real-time in vivo measurements of metabolite levels. Quantification of metabolite conversion between [1-13C]pyruvate and downstream metabolites [1-13C]alanine, [1-13C]lactate, and [13C]bicarbonate can be achieved through kinetic modeling. Since pyruvate interacts dynamically and simultaneously with its downstream metabolites, the purpose of this work is the determination of parameter values through a multisite, dynamic model involving possible biochemical pathways present in MR spectroscopy. Kinetic modeling parameters were determined by fitting the multisite model to time-domain dynamic metabolite data. The results for different pyruvate doses were compared with those of different two-site models to evaluate the hypothesis that for identical data the uncertainty of a model and the signal-to-noise ratio determine the sensitivity in detecting small physiological differences in the target metabolism. In comparison to the two-site exchange models, the multisite model yielded metabolic conversion rates with smaller bias and smaller standard deviation, as demonstrated in simulations with different signal-to-noise ratio. Pyruvate dose effects observed previously were confirmed and quantified through metabolic conversion rate values. Parameter interdependency allowed an accurate quantification and can therefore be useful for monitoring metabolic activity in different tissues.

  8. NH4+ triggers the release of astrocytic lactate via mitochondrial pyruvate shunting

    Science.gov (United States)

    Lerchundi, Rodrigo; Fernández-Moncada, Ignacio; Contreras-Baeza, Yasna; Sotelo-Hitschfeld, Tamara; Mächler, Philipp; Wyss, Matthias T.; Stobart, Jillian; Baeza-Lehnert, Felipe; Alegría, Karin; Weber, Bruno; Barros, L. Felipe

    2015-01-01

    Neural activity is accompanied by a transient mismatch between local glucose and oxygen metabolism, a phenomenon of physiological and pathophysiological importance termed aerobic glycolysis. Previous studies have proposed glutamate and K+ as the neuronal signals that trigger aerobic glycolysis in astrocytes. Here we used a panel of genetically encoded FRET sensors in vitro and in vivo to investigate the participation of NH4+, a by-product of catabolism that is also released by active neurons. Astrocytes in mixed cortical cultures responded to physiological levels of NH4+ with an acute rise in cytosolic lactate followed by lactate release into the extracellular space, as detected by a lactate-sniffer. An acute increase in astrocytic lactate was also observed in acute hippocampal slices exposed to NH4+ and in the somatosensory cortex of anesthetized mice in response to i.v. NH4+. Unexpectedly, NH4+ had no effect on astrocytic glucose consumption. Parallel measurements showed simultaneous cytosolic pyruvate accumulation and NADH depletion, suggesting the involvement of mitochondria. An inhibitor-stop technique confirmed a strong inhibition of mitochondrial pyruvate uptake that can be explained by mitochondrial matrix acidification. These results show that physiological NH4+ diverts the flux of pyruvate from mitochondria to lactate production and release. Considering that NH4+ is produced stoichiometrically with glutamate during excitatory neurotransmission, we propose that NH4+ behaves as an intercellular signal and that pyruvate shunting contributes to aerobic lactate production by astrocytes. PMID:26286989

  9. NH4(+) triggers the release of astrocytic lactate via mitochondrial pyruvate shunting.

    Science.gov (United States)

    Lerchundi, Rodrigo; Fernández-Moncada, Ignacio; Contreras-Baeza, Yasna; Sotelo-Hitschfeld, Tamara; Mächler, Philipp; Wyss, Matthias T; Stobart, Jillian; Baeza-Lehnert, Felipe; Alegría, Karin; Weber, Bruno; Barros, L Felipe

    2015-09-01

    Neural activity is accompanied by a transient mismatch between local glucose and oxygen metabolism, a phenomenon of physiological and pathophysiological importance termed aerobic glycolysis. Previous studies have proposed glutamate and K(+) as the neuronal signals that trigger aerobic glycolysis in astrocytes. Here we used a panel of genetically encoded FRET sensors in vitro and in vivo to investigate the participation of NH4(+), a by-product of catabolism that is also released by active neurons. Astrocytes in mixed cortical cultures responded to physiological levels of NH4(+) with an acute rise in cytosolic lactate followed by lactate release into the extracellular space, as detected by a lactate-sniffer. An acute increase in astrocytic lactate was also observed in acute hippocampal slices exposed to NH4(+) and in the somatosensory cortex of anesthetized mice in response to i.v. NH4(+). Unexpectedly, NH4(+) had no effect on astrocytic glucose consumption. Parallel measurements showed simultaneous cytosolic pyruvate accumulation and NADH depletion, suggesting the involvement of mitochondria. An inhibitor-stop technique confirmed a strong inhibition of mitochondrial pyruvate uptake that can be explained by mitochondrial matrix acidification. These results show that physiological NH4(+) diverts the flux of pyruvate from mitochondria to lactate production and release. Considering that NH4(+) is produced stoichiometrically with glutamate during excitatory neurotransmission, we propose that NH4(+) behaves as an intercellular signal and that pyruvate shunting contributes to aerobic lactate production by astrocytes.

  10. Metabolic imaging of patients with prostate cancer using hyperpolarized [1-¹³C]pyruvate

    DEFF Research Database (Denmark)

    Nelson, Sarah J; Kurhanewicz, John; Vigneron, Daniel B

    2013-01-01

    This first-in-man imaging study evaluated the safety and feasibility of hyperpolarized [1-¹³C]pyruvate as an agent for noninvasively characterizing alterations in tumor metabolism for patients with prostate cancer. Imaging living systems with hyperpolarized agents can result in more than 10,000-f...

  11. Embryonic Lethality of Mitochondrial Pyruvate Carrier 1 Deficient Mouse Can Be Rescued by a Ketogenic Diet

    Science.gov (United States)

    Krznar, Petra; Hörl, Manuel; Ammar, Zeinab; Montessuit, Sylvie; Pierredon, Sandra; Zamboni, Nicola; Martinou, Jean-Claude

    2016-01-01

    Mitochondrial import of pyruvate by the mitochondrial pyruvate carrier (MPC) is a central step which links cytosolic and mitochondrial intermediary metabolism. To investigate the role of the MPC in mammalian physiology and development, we generated a mouse strain with complete loss of MPC1 expression. This resulted in embryonic lethality at around E13.5. Mouse embryonic fibroblasts (MEFs) derived from mutant mice displayed defective pyruvate-driven respiration as well as perturbed metabolic profiles, and both defects could be restored by reexpression of MPC1. Labeling experiments using 13C-labeled glucose and glutamine demonstrated that MPC deficiency causes increased glutaminolysis and reduced contribution of glucose-derived pyruvate to the TCA cycle. Morphological defects were observed in mutant embryonic brains, together with major alterations of their metabolome including lactic acidosis, diminished TCA cycle intermediates, energy deficit and a perturbed balance of neurotransmitters. Strikingly, these changes were reversed when the pregnant dams were fed a ketogenic diet, which provides acetyl-CoA directly to the TCA cycle and bypasses the need for a functional MPC. This allowed the normal gestation and development of MPC deficient pups, even though they all died within a few minutes post-delivery. This study establishes the MPC as a key player in regulating the metabolic state necessary for embryonic development, neurotransmitter balance and post-natal survival. PMID:27176894

  12. Pyruvate Kinase Triggers a Metabolic Feedback Loop that Controls Redox Metabolism in Respiring Cells

    NARCIS (Netherlands)

    Grüning, N.M.; Rinnerthaler, M.; Bluemlein, K.; Mulleder, M.; Wamelink, M.M.C.; Lehrach, H.; Jakobs, C.A.J.M.; Breitenbach, M.; Ralser, M.

    2011-01-01

    In proliferating cells, a transition from aerobic to anaerobic metabolism is known as the Warburg effect, whose reversal inhibits cancer cell proliferation. Studying its regulator pyruvate kinase (PYK) in yeast, we discovered that central metabolism is self-adapting to synchronize redox metabolism

  13. Hyperpolarized 1-13C Pyruvate Imaging of Porcine Cardiac Metabolism shift by GIK Intervention

    DEFF Research Database (Denmark)

    Søvsø Szocska Hansen, Esben; Tougaard, Rasmus Stilling; Mikkelsen, Emmeli

    to evaluate the general feasibility to detect an imposed shift in metabolic substrate utilization during metabolic modulation with glucose, insulin and potassium (GIK) infusion. This study demonstrates that hyperpolarized 13C-pyruvate, in a large animal, is a feasible method for cardiac studies, and...

  14. Exercise-induced pyruvate dehydrogenase activation is not affected by 7 days of bed rest

    DEFF Research Database (Denmark)

    Kiilerich, Kristian; Jørgensen, Stine Ringholm; Biensø, Rasmus Sjørup

    2011-01-01

    To test the hypothesis that physical inactivity impairs the exercise-induced modulation of pyruvate dehydrogenase (PDH), 6 healthy normally physically active male subjects completed 7 days of bed rest. Before and immediately after the bed rest, the subjects completed an OGTT and a one-legged knee...

  15. Modification of Cys-418 of pyruvate formate-lyase by methacrylic acid, based on its radical mechanism.

    Science.gov (United States)

    Plaga, W; Vielhaber, G; Wallach, J; Knappe, J

    2000-01-21

    The recently determined crystal structure of pyruvate formate-lyase (PFL) suggested a new view of the mechanism of this glycyl radical enzyme, namely that intermediary thiyl radicals of Cys-418 and Cys-419 participate in different ways [Becker, A. et al. (1999) Nat. Struct. Biol. 6, 969-975]. We report here a suicide reaction of PFL that occurs with the substrate-analog methacrylate with retention of the protein radical (K(I)=0.42 mM, k(i)=0.14 min(-1)). Using [1-(14)C]methacrylate (synthesized via acetone cyanhydrin), the reaction end-product was identified by peptide mapping and cocrystallization experiments as S-(2-carboxy-(2S)-propyl) substituted Cys-418. The stereoselectivity of the observed Michael addition reaction is compatible with a radical mechanism that involves Cys-418 thiyl as nucleophile and Cys-419 as H-atom donor, thus supporting the functional assignments of these catalytic amino acid residues derived from the protein structure.

  16. Et evalueringseksperiment

    DEFF Research Database (Denmark)

    Christensen, Torben Spanget

    2008-01-01

    Artiklen præsenterer et evalueringseksperiment foretaget i 8 klasserum. Der er tale om mundtlige formative evalueringer som har fokus på elevernes faglige viden. Artiklen præsenterer en model for fagligt evaluerende lærer-elevsamtaler (FE-samtaler) som er udviklet i eksperimentet og resultaterne af...

  17. Neuron-astrocyte interactions, pyruvate carboxylation and the pentose phosphate pathway in the neonatal rat brain.

    Science.gov (United States)

    Morken, Tora Sund; Brekke, Eva; Håberg, Asta; Widerøe, Marius; Brubakk, Ann-Mari; Sonnewald, Ursula

    2014-01-01

    Glucose and acetate metabolism and the synthesis of amino acid neurotransmitters, anaplerosis, glutamate-glutamine cycling and the pentose phosphate pathway (PPP) have been extensively investigated in the adult, but not the neonatal rat brain. To do this, 7 day postnatal (P7) rats were injected with [1-(13)C]glucose and [1,2-(13)C]acetate and sacrificed 5, 10, 15, 30 and 45 min later. Adult rats were injected and sacrificed after 15 min. To analyse pyruvate carboxylation and PPP activity during development, P7 rats received [1,2-(13)C]glucose and were sacrificed 30 min later. Brain extracts were analysed using (1)H- and (13)C-NMR spectroscopy. Numerous differences in metabolism were found between the neonatal and adult brain. The neonatal brain contained lower levels of glutamate, aspartate and N-acetylaspartate but similar levels of GABA and glutamine per mg tissue. Metabolism of [1-(13)C]glucose at the acetyl CoA stage was reduced much more than that of [1,2-(13)C]acetate. The transfer of glutamate from neurons to astrocytes was much lower while transfer of glutamine from astrocytes to glutamatergic neurons was relatively higher. However, transport of glutamine from astrocytes to GABAergic neurons was lower. Using [1,2-(13)C]glucose it could be shown that despite much lower pyruvate carboxylation, relatively more pyruvate from glycolysis was directed towards anaplerosis than pyruvate dehydrogenation in astrocytes. Moreover, the ratio of PPP/glucose-metabolism was higher. These findings indicate that only the part of the glutamate-glutamine cycle that transfers glutamine from astrocytes to neurons is operating in the neonatal brain and that compared to adults, relatively more glucose is prioritised to PPP and pyruvate carboxylation. Our results may have implications for the capacity to protect the neonatal brain against excitotoxicity and oxidative stress.

  18. Protective effect of pyruvate against ethanol-induced apoptotic neurodegeneration in the developing rat brain.

    Science.gov (United States)

    Ullah, Najeeb; Naseer, Muhammad Imran; Ullah, Ikram; Lee, Hae Young; Koh, Phil Ok; Kim, Myeong Ok

    2011-12-01

    Exposure to alcohol during the early stages of brain development can lead to neurological disorders in the CNS. Apoptotic neurodegeneration due to ethanol exposure is a main feature of alcoholism. Exposure of developing animals to alcohol (during the growth spurt period in particular) elicits apoptotic neuronal death and causes fetal alcohol effects (FAE) or fetal alcohol syndrome (FAS). A single episode of ethanol intoxication (at 5 g/kg) in a seven-day-old developing rat can activate the apoptotic cascade, leading to widespread neuronal death in the brain. In the present study, we investigated the potential protective effect of pyruvate against ethanol-induced neuroapoptosis. After 4h, a single dose of ethanol induced upregulation of Bax, release of mitochondrial cytochrome-c into the cytosol, activation of caspase-3 and cleavage of poly (ADP-ribose) polymerase (PARP-1), all of which promote apoptosis. These effects were all reversed by co-treatment with pyruvate at a well-tolerated dosage (1000 mg/kg). Histopathology performed at 24 and 48 h with Fluoro-Jade-B and cresyl violet stains showed that pyruvate significantly reduced the number of dead cells in the cerebral cortex, hippocampus and thalamus. Immunohistochemical analysis at 24h confirmed that ethanol-induced cell death is both apoptotic and inhibited by pyruvate. These findings suggest that pyruvate treatment attenuates ethanol-induced neuronal cell loss in the developing rat brain and holds promise as a safe therapeutic and neuroprotective agent in the treatment of neurodegenerative disorders in newborns and infants. Copyright © 2011 Elsevier Ltd. All rights reserved.

  19. 13C NMR study of effects of fasting and diabetes on the metabolism of pyruvate in the tricarboxylic acid cycle and of the utilization of pyruvate and ethanol in lipogenesis in perfused rat liver

    International Nuclear Information System (INIS)

    Cohen, S.M.

    1987-01-01

    13 C NMR has been used to study the competition of pyruvate dehydrogenase with pyruvate carboxylase for entry of pyruvate into the tricarboxylic acid (TCA) cycle in perfused liver from streptozotocin-diabetic and normal donor rats. The relative proportion of pyruvate entering the TCA cycle by these two routes was estimated from the 13 C enrichments at the individual carbons of glutamate when [3- 13 C]alanine was the only exogenous substrate present. In this way, the proportion of pyruvate entering by the pyruvate dehydrogenase route relative to the pyruvate carboxylase route was determined to be 1:1.2 +/- 0.1 in liver from fed controls, 1:7.7 +/- 2 in liver from 24-fasted controls, and 1:2.6 +/- 0.3 in diabetic liver. Pursuant to this observation that conversion of pyruvate to acetyl coenzyme A (acetyl-CoA) was greatest in perfused liver from fed controls, the incorporation of 13 C label into fatty acids was monitored in this liver preparation. With the exception of the repeating methylene carbons, fatty acyl carbons labeled by [1- 13 C]acetyl-CoA (from [2- 13 C]pyruvate) gave rise to resonances distinguishable on the basis of chemical shift from those observed when label was introduced by [3- 13 C]alanine plus [2- 13 C]ethanol, which are converted to [2- 13 C]acetyl-CoA. Thus, measurement of 13 C enrichment at several specific sites in the fatty acyl chains in time-resolved spectra of perfused liver offers a novel way of monitoring the kinetics of the biosynthesis of fatty acids. In addition to obtaining the rate of lipogenesis, it was possible to distinguish the contributions of chain elongation from those of the de novo synthesis pathway and to estimate the average chain length of the 13 C-labeled fatty acids produced

  20. Extracellular polysaccharides are involved in the attachment of Azospirillum brasilense and Rhizobium leguminosarum to arbuscular mycorrhizal structures

    Directory of Open Access Journals (Sweden)

    V Bianciotto

    2009-12-01

    Full Text Available Arbuscular mycorrhizal (AM fungi, one of the most important component of the soil microbial community, establish physical interactions with naturally occurring and genetically modified bacterial biofertilizers and biopesticides, commonly referred to as plant growth-promoting rhizobacteria (PGPR. We have used a genetic approach to investigate the bacterial components possibly involved in the attachment of two PGPR (Azospirillum and Rhizobium to AM roots and AM fungal structures. Mutants affected in extracellular polysaccharides (EPS have been tested in in vitro adhesion assays and shown to be strongly impaired in the attachment to both types of surfaces as well as to quartz fibers. Anchoring of rhizobacteria to AM fungal structures may have special ecological and biotechnological significance because it may facilitate colonisation of new rhizospheres by the bacteria, and may be an essential trait for the development of mixed inocula.

  1. Mechanisms of protection of pea plants by polysaccharides extracted from a strain of Rhizobium against Orobanche crenata

    International Nuclear Information System (INIS)

    Khairi, Hanene; Temani, Randa

    2009-01-01

    The Broomrape causes notable damage on the leguminous crops and became major factor limiting production of pea in the Mediterranean region. The effect of the polysaccharides extracted from P.SOM Rhizobium strain on the development of Orobanche crenata on pea was studied. The results showed that the lipopolysaccharides significantly reduce the infestation of pea by O. crenata. This limitation of infestation results from the reduction of seeds germination rates of the parasite resulting in reduction of the tubercles number on pea roots. Moreover, necrosis of orobanche before or after attachment on pea roots treated by LPS can explain this reduction of parasitism. A correlation was observed between the reduction of pea infection by the broomrape and the activation phenolic compounds pathway. This activation resulted to increase of two enzymes (peroxidase and polyphenoloxidase) activities these enzymes are implicated in plant defense. The results of our study showed that the LPS seem implied in the induction of pea resistance against the broomrape.

  2. A Rhizobium leguminosarum CHDL- (Cadherin-Like-) Lectin Participates in Assembly and Remodeling of the Biofilm Matrix

    DEFF Research Database (Denmark)

    Vozza, Nicolás F.; Abdian, Patricia L; Russo, Daniela M

    2016-01-01

    In natural environments most bacteria live in multicellular structures called biofilms. These cell aggregates are enclosed in a self-produced polymeric extracellular matrix, which protects the cells, provides mechanical stability and mediates cellular cohesion and adhesion to surfaces. Although...... important advances were made in the identification of the genetic and extracellular factors required for biofilm formation, the mechanisms leading to biofilm matrix assembly, and the roles of extracellular proteins in these processes are still poorly understood. The symbiont Rhizobium leguminosarum requires...... the synthesis of the acidic exopolysaccharide and the PrsDE secretion system to develop a mature biofilm. PrsDE is responsible for the secretion of the Rap family of proteins that share one or two Ra/CHDL (cadherin-like-) domains. RapA2 is a calcium-dependent lectin with a cadherin-like β sheet structure...

  3. Response of lupine plants irrigated with saline water to rhizobium inoculation using 15N-isotope dilution

    International Nuclear Information System (INIS)

    Gadalla, A.M.; El-Ghandour, I.A.; Abdel Aziz, H.A.; Hamdy, A.; Aly, M.M.

    2002-01-01

    The lupine Rhizobium symbiosis and contribution of N 2 fixation under different levels of irrigation water salinity were examined. Lysimeter experiment was established under greenhouse conditions during the year 2002-2003. In this experiment, inoculated plants were imposed to different salinity levels of irrigation water and N-fertilizer treatment. Plant height was decreased under different salinity levels, nitrogen treatments and bacterial inoculation. Similar trend was noticed with leaf area. The highest leaf area was recorded with salt tolerant bacterial inoculation (SBI) and splitting N-treatment. Highest values of N-uptake occurred after 100 day intervals under the tested factors. Relative decrease in N-uptake did not exceed 40% of those recorded with the fresh water treatment as affected by experimental factors. Nitrogen uptake by the whole plant reflected an increase at 3 dS/m salinity level of irrigation water. Relative increases were 5% and 15% for normal bacteria inoculation under single dose (NI) and splitting

  4. Agro-Economic Optimization of Fertilizer Level and Rhizobium Strains for Enhanced Grain Yield in Mungbean (Vigna Radiata L.)

    International Nuclear Information System (INIS)

    Mansoor, M.; Elahi, M. E.; Islam, Z.; Ali, A.

    2016-01-01

    To explore the effect of PGPR for improvement in grain yield of mungbean, different levels of fertilizer (00:00, 20:50 and 20:70 kg N:P/sub 2/O/sub 5/ kg ha/sup -1/) were tested on four strains (CB 1015 Australia, Vm-L1, Vm-M1 and Vm-M2) at Agricultural Research Institute, Dera Ismail Khan. A Randomized Complete Block Design with split plot arrangement was used to conduct the experiment by keeping three fertilizer levels in the main plot and Rhizobium strains in sub-plot. The data were recorded for different parameters like number of branches plant/sup -1/, number of clusters plant/sup -1/, number of pods plant/sup -1/., number of grain pod/sup -1/, pod length (cm) and grain yield kg ha/sup -1/. The response of fertilizer levels and inoculation with Rhizobium strains were found significant in most of the parameters under study. The strain Vm-M1 produced the highest number of branches plant/sup -1/(5.42), number of clusters plant/sup -1/(22.92), number of pods plant/sup -1/(77.64), pod length (8.37 cm) when applied in combination of N:P/sub 2/O/sub 5/ at the rate of 20:70 and 20:50 kg ha/sup -1/. Although the grain yield (1421 kg ha/sup -1/) recorded in treatment (20:70 kg N:P/sub 2/O/sub 5/ ha/sup -1/ + Inoculation with strain Vm M1) was highest but economically the treatment (20:50 kg N:P/sub 2/O/sub 5/ ha/sup -1/ + inoculation with strain Vm M1) with net return of Rs. 13618 ha/sup -1/ and BCR of 2.52 was on top. (author)

  5. Nickel detoxification and plant growth promotion by multi metal resistant plant growth promoting Rhizobium species RL9.

    Science.gov (United States)

    Wani, Parvaze Ahmad; Khan, Mohammad Saghir

    2013-07-01

    Pollution of the biosphere by heavy metals is a global threat that has accelerated dramatically since the beginning of industrial revolution. The aim of the study is to check the resistance of RL9 towards the metals and to observe the effect of Rhizobium species on growth, pigment content, protein and nickel uptake by lentil in the presence and absence of nickel. The multi metal tolerant and plant growth promoting Rhizobium strain RL9 was isolated from the nodules of lentil. The strain not only tolerated nickel but was also tolerant o cadmium, chromium, nickel, lead, zinc and copper. The strain tolerated nickel 500 μg/mL, cadmium 300 μg/mL, chromium 400 μg/mL, lead 1,400 μg/mL, zinc 1,000 μg/mL and copper 300 μg/mL, produced good amount of indole acetic acid and was also positive for siderophore, hydrogen cyanide and ammonia. The strain RL9 was further assessed with increasing concentrations of nickel when lentil was used as a test crop. The strain RL9 significantly increased growth, nodulation, chlorophyll, leghaemoglobin, nitrogen content, seed protein and seed yield compared to plants grown in the absence of bioinoculant but amended with nickel The strain RL9 decreased uptake of nickel in lentil compared to plants grown in the absence of bio-inoculant. Due to these intrinsic abilities strain RL9 could be utilized for growth promotion as well as for the remediation of nickel in nickel contaminated soil.

  6. Mutualism and Adaptive Divergence: Co-Invasion of a Heterogeneous Grassland by an Exotic Legume-Rhizobium Symbiosis

    Science.gov (United States)

    Porter, Stephanie S.; Stanton, Maureen L.; Rice, Kevin J.

    2011-01-01

    Species interactions play a critical role in biological invasions. For example, exotic plant and microbe mutualists can facilitate each other's spread as they co-invade novel ranges. Environmental context may influence the effect of mutualisms on invasions in heterogeneous environments, however these effects are poorly understood. We examined the mutualism between the legume, Medicago polymorpha, and the rhizobium, Ensifer medicae, which have both invaded California grasslands. Many of these invaded grasslands are composed of a patchwork of harsh serpentine and relatively benign non-serpentine soils. We grew legume genotypes collected from serpentine or non-serpentine soil in both types of soil in combination with rhizobium genotypes from serpentine or non-serpentine soils and in the absence of rhizobia. Legumes invested more strongly in the mutualism in the home soil type and trends in fitness suggested that this ecotypic divergence was adaptive. Serpentine legumes had greater allocation to symbiotic root nodules in serpentine soil than did non-serpentine legumes and non-serpentine legumes had greater allocation to nodules in non-serpentine soil than did serpentine legumes. Therefore, this invasive legume has undergone the rapid evolution of divergence for soil-specific investment in the mutualism. Contrary to theoretical expectations, the mutualism was less beneficial for legumes grown on the stressful serpentine soil than on the non-serpentine soil, possibly due to the inhibitory effects of serpentine on the benefits derived from the interaction. The soil-specific ability to allocate to a robust microbial mutualism may be a critical, and previously overlooked, adaptation for plants adapting to heterogeneous environments during invasion. PMID:22174755

  7. Mutualism and adaptive divergence: co-invasion of a heterogeneous grassland by an exotic legume-rhizobium symbiosis.

    Directory of Open Access Journals (Sweden)

    Stephanie S Porter

    Full Text Available Species interactions play a critical role in biological invasions. For example, exotic plant and microbe mutualists can facilitate each other's spread as they co-invade novel ranges. Environmental context may influence the effect of mutualisms on invasions in heterogeneous environments, however these effects are poorly understood. We examined the mutualism between the legume, Medicago polymorpha, and the rhizobium, Ensifer medicae, which have both invaded California grasslands. Many of these invaded grasslands are composed of a patchwork of harsh serpentine and relatively benign non-serpentine soils. We grew legume genotypes collected from serpentine or non-serpentine soil in both types of soil in combination with rhizobium genotypes from serpentine or non-serpentine soils and in the absence of rhizobia. Legumes invested more strongly in the mutualism in the home soil type and trends in fitness suggested that this ecotypic divergence was adaptive. Serpentine legumes had greater allocation to symbiotic root nodules in serpentine soil than did non-serpentine legumes and non-serpentine legumes had greater allocation to nodules in non-serpentine soil than did serpentine legumes. Therefore, this invasive legume has undergone the rapid evolution of divergence for soil-specific investment in the mutualism. Contrary to theoretical expectations, the mutualism was less beneficial for legumes grown on the stressful serpentine soil than on the non-serpentine soil, possibly due to the inhibitory effects of serpentine on the benefits derived from the interaction. The soil-specific ability to allocate to a robust microbial mutualism may be a critical, and previously overlooked, adaptation for plants adapting to heterogeneous environments during invasion.

  8. Effect of thiamine deficiency, pyrithiamine and oxythiamine on pyruvate metabolism in rat liver and brain in vivo

    International Nuclear Information System (INIS)

    Meghal, S.K.; O'Neal, R.M.; Koeppe, R.E.

    1977-01-01

    Rats were fed either a thiamine-deficient diet or diets containing pyrithiamine or oxythiamine. When symptoms of thiamine deficiency appeared, the animals were injected intraperitoneally with [2- 14 C] pyruvate six to twelve minutes prior to sacrifice. Free glutamic and aspartic acids were isolated from liver and brain and degraded. The results indicate that, in thiamine-deficient or oxythiamine-treated rats, pyruvate metabolism in liver and brain is similar to that in normal animals. In contrast, pyrithinamine drastically decreases the oxidative decarboxylation of pyruvate by rat liver. (auth.)

  9. Regulation of pyruvate oxidation in blowfly flight muscle mitochondria: requirement for ADP.

    Science.gov (United States)

    Bulos, B A; Thomas, B J; Shukla, S P; Sacktor, B

    1984-11-01

    Blowfly (Phormia regina) flight muscle mitochondria oxidized pyruvate ( + proline) in the presence of either ADP (coupled respiration) or carbonylcyanide-p-trifluoromethoxyphenylhydrazone (FCCP-uncoupled respiration). There was an absolute requirement for ADP (Km = 8.0 microM) when pyruvate oxidation was stimulated by FCCP in the presence of oligomycin. This requirement for ADP was limited to the oxidation of pyruvate; uncoupled alpha-glycerolphosphate oxidation proceeded maximally even in the absence of added ADP. Atractylate inhibited uncoupled pyruvate oxidation whether added before (greater than 99%) or after (95%) initiation of respiration with FCCP. In the presence of FCCP, oligomycin, and limiting concentrations of ADP (less than 110 microM), there was a shutoff in the uptake of oxygen. This inhibition of respiration was completely reversed by the addition of more ADP. Plots of net oxygen uptake as a function of the limiting ADP concentration were linear; the observed ADP/O ratio was 0.22 +/- 0.025. An ADP/O ratio of 0.2 was predicted if phosphorylation occurred only at the succinyl-CoA synthetase step of the tricarboxylate cycle. Experiments performed in the presence of limiting concentrations of ADP, and designed to monitor changes in the mitochondrial content of ADP and ATP, demonstrated that the shutoff in oxygen uptake was not due to the presence of a high intramitochondrial concentration of ATP. Indeed, ATP, added to the medium prior to the addition of FCCP, inhibited uncoupled pyruvate oxidation; the apparent KI was 0.8 mM. These results are consistent with the hypothesis that it is the intramitochondrial ATP/ADP ratio that is one of the controlling factors in determining the rate of flux through the tricarboxylate cycle. Changes in the mitochondrial content of citrate, isocitrate, alpha-ketoglutarate, and malate during uncoupled pyruvate oxidation in the presence of a limiting concentration of ADP were consistent with the hypothesis that the

  10. Reprint of "How do components of real cloud water affect aqueous pyruvate oxidation?"

    Science.gov (United States)

    Boris, Alexandra J.; Desyaterik, Yury; Collett, Jeffrey L.

    2015-01-01

    Chemical oxidation of dissolved volatile or semi-volatile organic compounds within fog and cloud droplets in the atmosphere could be a major pathway for secondary organic aerosol (SOA) formation. This proposed pathway consists of: (1) dissolution of organic chemicals from the gas phase into a droplet; (2) reaction with an aqueous phase oxidant to yield low volatility products; and (3) formation of particle phase organic matter as the droplet evaporates. The common approach to simulating aqueous SOA (aqSOA) reactions is photo-oxidation of laboratory standards in pure water. Reactions leading to aqSOA formation should be studied within real cloud and fog water to determine whether additional competing processes might alter apparent rates of reaction as indicated by rates of reactant loss or product formation. To evaluate and identify the origin of any cloud water matrix effects on one example of observed aqSOA production, pyruvate oxidation experiments simulating aqSOA formation were monitored within pure water, real cloud water samples, and an aqueous solution of inorganic salts. Two analysis methods were used: online electrospray ionization high-resolution time-of-flight mass spectrometry (ESI-HR-ToF-MS), and offline anion exchange chromatography (IC) with quantitative conductivity and qualitative ESI-HR-ToF-MS detection. The apparent rate of oxidation of pyruvate was slowed in cloud water matrices: overall measured degradation rates of pyruvate were lower than in pure water. This can be at least partially accounted for by the observed formation of pyruvate from reactions of other cloud water components. Organic constituents of cloud water also compete for oxidants and/or UV light, contributing to the observed slowed degradation rates of pyruvate. The oxidation of pyruvate was not significantly affected by the presence of inorganic anions (nitrate and sulfate) at cloud-relevant concentrations. Future bulk studies of aqSOA formation reactions using simplified

  11. Carbon-14 tracer studies in rat-liver perfusion experiments under conditions of gluconeogenesis from lactate and pyruvate

    International Nuclear Information System (INIS)

    Muellhofer, G.; Schwab, A.; Mueller, C.; Stetten, C. von; Gruber, E.

    1977-01-01

    The intracellular events in the metabolic pathway of gluconeogenesis from lactate and pyruvate in liver tissue were assumed to be understood. Nevertheless the results of several 14 C-tracer experiments gave rise to the postulation of still unknown intracellular interactions under this condition. A contribution was made to the solution of this problem by using different 14 C labelled tracers such as [1- 14 C]lactate or pyruvate and [2- 14 C]lactate or pyruvate. [ 14 C]bicarbonate and [1- 14 C]-octanoate in perfusion experiments with livers from rats under conditions of gluconeogenesis from lactate and pyruvate. The 14 C labelling patterns of intracellular metabolities such as malate, citrate, phosphoenolpyruvate, phosphoglycerate and newly synthesized glucose were analysed under different conditions. A comparison with values calculated by using metabolic models based on the generally accepted concepts of intracellular interactions showed some fundamental discrepancies which justify the postulation. (orig./MG) [de

  12. Investigating tumor perfusion and metabolism using multiple hyperpolarized 13C compounds: HP001, pyruvate and urea

    DEFF Research Database (Denmark)

    von Morze, Cornelius; Larson, Peder E.Z.; Hu, Simon

    2012-01-01

    The metabolically inactive hyperpolarized agents HP001 (bis-1,1-(hydroxymethyl)-[1-13C]cyclopropane-d8) and urea enable a new type of perfusion magnetic resonance imaging based on a direct signal source that is background-free. The addition of perfusion information to metabolic information obtained...... (T1=95 s ex vivo, 32 s in vivo at 3 T) using a pulse sequence with balanced steady-state free precession and ramped flip angle over time for efficient utilization of the hyperpolarized magnetization and three-dimensional echo-planar spectroscopic imaging of urea copolarized with [1-13C...... of separate dynamic HP001 imaging and copolarized pyruvate/urea imaging were compared. A strong and significant correlation (R=0.73, P=.02) detected between the urea and HP001 data confirmed the value of copolarizing urea with pyruvate for simultaneous assessment of perfusion and metabolism....

  13. Propionate Increases Hepatic Pyruvate Cycling and Anaplerosis and Alters Mitochondrial Metabolism

    DEFF Research Database (Denmark)

    Perry, Rachel J; Borders, Candace B; Cline, Gary W

    2016-01-01

    /tandem-mass spectrometry (LC-MS/MS) method to directly assess pyruvate cycling relative to mitochondrial pyruvate metabolism (VPyr-Cyc/VMito) in vivo using [3-(13)C]lactate as a tracer. Using this approach, VPyr-Cyc/VMito was only 6% in overnight fasted rats. In contrast, when propionate was infused simultaneously...... at doses previously used as a tracer, it increased VPyr-Cyc/VMito by 20-30-fold, increased hepatic TCA metabolite concentrations 2-3-fold, and increased endogenous glucose production rates by 20-100%. The physiologic stimuli, glucagon and epinephrine, both increased hepatic glucose production, but only...... tracer to assess hepatic glycolytic, gluconeogenic, and mitochondrial metabolism in vivo....

  14. Expression of Aeromonas caviae ST pyruvate dehydrogenase complex components mediate tellurite resistance in Escherichia coli

    International Nuclear Information System (INIS)

    Castro, Miguel E.; Molina, Roberto C.; Diaz, Waldo A.; Pradenas, Gonzalo A.; Vasquez, Claudio C.

    2009-01-01

    Potassium tellurite (K 2 TeO 3 ) is harmful to most organisms and specific mechanisms explaining its toxicity are not well known to date. We previously reported that the lpdA gene product of the tellurite-resistant environmental isolate Aeromonas caviae ST is involved in the reduction of tellurite to elemental tellurium. In this work, we show that expression of A. caviae ST aceE, aceF, and lpdA genes, encoding pyruvate dehydrogenase, dihydrolipoamide transacetylase, and dihydrolipoamide dehydrogenase, respectively, results in tellurite resistance and decreased levels of tellurite-induced superoxide in Escherichia coli. In addition to oxidative damage resulting from tellurite exposure, a metabolic disorder would be simultaneously established in which the pyruvate dehydrogenase complex would represent an intracellular tellurite target. These results allow us to widen our vision regarding the molecular mechanisms involved in bacterial tellurite resistance by correlating tellurite toxicity and key enzymes of aerobic metabolism.

  15. Enzyme mechanisms for pyruvate-to-lactate flux attenuation: a study of Sherpas, Quechuas, and hummingbirds.

    Science.gov (United States)

    Hochachka, P W; Stanley, C; McKenzie, D C; Villena, A; Monge, C

    1992-10-01

    During incremental exercise to fatigue under hypobaric hypoxia, Andean Quechua natives form and accumulate less plasma lactate than do lowlanders under similar conditions. This phenomenon of low lactate accumulation despite hypobaric hypoxia, first discovered some half century ago, is known in Quechuas to be largely unaffected by acute exposure to hypoxia or by acclimatization to sea level conditions. Earlier Nuclear Magnetic Resonance (NMR) spectroscopy and metabolic biochemistry studies suggest that closer coupling of energy demand and energy supply in Quechuas allows given changes in work rate with relatively modest changes in muscle adenylate and phosphagen concentrations, thus tempering the activation of glycolytic flux to pyruvate--a coarse control mechanism operating at the level of overall pathway flux. Later studies of enzyme activities in skeletal muscles of Quechuas and of Sherpas have identified a finely-tuned control mechanism which by adaptive modifications of a few key enzymes apparently serves to specifically attenuate pyruvate flux to lactate.

  16. MCA Vmean and the arterial lactate-to-pyruvate ratio correlate during rhythmic handgrip

    DEFF Research Database (Denmark)

    Rasmussen, Peter; Plomgaard, Peter; Krogh-Madsen, Rikke

    2006-01-01

    /P ratio at two plasma lactate levels. MCA Vmean was determined by ultrasound Doppler sonography at rest, during 10 min of rhythmic handgrip exercise at approximately 65% of maximal voluntary contraction force, and during 20 min of recovery in seven healthy male volunteers during control...... and a approximately 15 mmol/l hyperglycemic clamp. Cerebral arteriovenous differences for metabolites were obtained by brachial artery and retrograde jugular venous catheterization. Control resting arterial lactate was 0.78 +/- 0.09 mmol/l (mean +/- SE) and pyruvate 55.7 +/- 12.0 micromol/l (L/P ratio 16.4 +/- 1......Regulation of cerebral blood flow during physiological activation including exercise remains unknown but may be related to the arterial lactate-to-pyruvate (L/P) ratio. We evaluated whether an exercise-induced increase in middle cerebral artery mean velocity (MCA Vmean) relates to the arterial L...

  17. Adaptive mutations in sugar metabolism restore growth on glucose in a pyruvate decarboxylase negative yeast strain

    DEFF Research Database (Denmark)

    Zhang, Yiming; Liu, Guodong; Engqvist, Martin K. M.

    2015-01-01

    Background: A Saccharomyces cerevisiae strain carrying deletions in all three pyruvate decarboxylase (PDC) genes (also called Pdc negative yeast) represents a non-ethanol producing platform strain for the production of pyruvate derived biochemicals. However, it cannot grow on glucose as the sole...... DNA sequencing. Among these genetic changes, 4 genes were found to carry point mutations in at least two of the evolved strains: MTH1 encoding a negative regulator of the glucose-sensing signal transduction pathway, HXT2 encoding a hexose transporter, CIT1 encoding a mitochondrial citrate synthase...... further increased the maximum specific growth rate to 0.069 h-1. Conclusions: In this study, possible evolving mechanisms of Pdc negative strains on glucose were investigated by genome sequencing and reverse engineering. The non-synonymous mutations in MTH1 alleviated the glucose repression by repressing...

  18. Anaerobic survival of Pseudomonas aeruginosa by pyruvate fermentation requires an Usp-type stress protein

    DEFF Research Database (Denmark)

    Schreiber, K; Boes, N; Escbach, M

    2006-01-01

    the induced synthesis of three enzymes involved in arginine fermentation, ArcA, ArcB, and ArcC, and the outer membrane protein OprL. Moreover, formation of two proteins of unknown function, PA3309 and PA4352, increased by factors of 72- and 22-fold, respectively. Both belong to the group of universal stress...... proteins (Usp). Long-term survival of a PA3309 knockout mutant by pyruvate fermentation was found drastically reduced. The oxygen-sensing regulator Anr controls expression of the PPA3309-lacZ reporter gene fusion after a shift to anaerobic conditions and further pyruvate fermentation. PA3309 expression...... was also found induced during the anaerobic and aerobic stationary phases. This aerobic stationary-phase induction is independent of the regulatory proteins Anr, RpoS, RelA, GacA, RhlR, and LasR, indicating a currently unknown mechanism of stationary-phase-dependent gene activation. PA3309 promoter...

  19. Regulation of pyruvate dehydrogenase kinase expression by the farnesoid X receptor

    International Nuclear Information System (INIS)

    Savkur, Rajesh S.; Bramlett, Kelli S.; Michael, Laura F.; Burris, Thomas P.

    2005-01-01

    The pyruvate dehydrogenase complex (PDC) functions as an important junction in intermediary metabolism by influencing the utilization of fat versus carbohydrate as a source of fuel. Activation of PDC is achieved by phosphatases, whereas, inactivation is catalyzed by pyruvate dehydrogenase kinases (PDKs). The expression of PDK4 is highly regulated by the glucocorticoid and peroxisome proliferator-activated receptors. We demonstrate that the farnesoid X receptor (FXR; NR1H4), which regulates a variety of genes involved in lipoprotein metabolism, also regulates the expression of PDK4. Treatment of rat hepatoma cells as well as human primary hepatocytes with FXR agonists stimulates the expression of PDK4 to levels comparable to those obtained with glucocorticoids. In addition, treatment of mice with an FXR agonist significantly increased hepatic PDK4 expression, while concomitantly decreasing plasma triglyceride levels. Thus, activation of FXR may suppress glycolysis and enhance oxidation of fatty acids via inactivation of the PDC by increasing PDK4 expression

  20. Iron may induce both DNA synthesis and repair in rat hepatocytes stimulated by EGF/pyruvate

    Energy Technology Data Exchange (ETDEWEB)

    Chenoufi, N.; Loreal, O.; Cariou, S.; Hubert, N.; Lescoat, G. [Univ. Hospital Pontchaillou, Unite de Recherches Hepatologiques, INSERM U 49, Rennes (France); Drenou, B. [Univ. Hospital Pontchaillou, Lab. d`Hematologie et d`Immunologie, Rennes (France); Leroyer, P.; Brissot, P. [Univ. Hospital Pontchaillou, Clinique des Maladies du Foie, Rennes (France)

    1997-03-01

    Background/Aims: Hepatocellular carcinoma develops frequently in the course of genetic hemochromatosis, and a role of iron overload in hepatic carcinogenesis is strongly suggested. Methods: The aim of our study was to investigate the effect of iron exposure on DNA synthesis of adult rat hepatocytes maintained in primary culture stimulated or not by EGF/pyruvate and exposed to iron-citrate complex. Results: In EGF/pyruvate-stimulated cultures, the level of [{sup 3}H] methyl thymidine incorporation was strongly increased as compared to unstimulated cultures. The addition of iron to stimulated cultures increased [{sup 3}H] methyl thymidine incorporation. The mitotic index was also significantly higher at 72 h. However,the number of cells found in the cell layer was not significantly different from iron-citrate free culture. By flow cytometry, no difference in cell ploidy was found between iron-treated and untreated EGF/pyruvate-stimulated cultures. A significant increase in LDH leakage reflecting a toxic effect of iron was found in the cell medium 48 h after cell seeding. In addition, [{sup 3}H] methyl thymidine incorporation in the presence of hydroxyurea was increased in iron-treated compared to untreated cultures. Conclusions: Our results show that DNA synthesis is increased in the presence of iron in rat hepatocyte cultures stimulated by EGF/pyruvate, and they suggest that DNA synthesis is likely to be related both to cell proliferation and to DNA repair. These observations may allow better understanding of the role of iron overload in the development of hepatocellular carcinoma. (au) 61 refs.

  1. Sodium Pyruvate Reduced Hypoxic-Ischemic Injury to Neonatal Rat Brain

    OpenAIRE

    Pan, Rui; Rong, Zhihui; She, Yun; Cao, Yuan; Chang, Li-Wen; Lee, Wei-Hua

    2012-01-01

    Background Neonatal hypoxia-ischemia (HI) remains a major cause of severe brain damage and is often associated with high mortality and lifelong disability. Immature brains are extremely sensitive to hypoxia-ischemia, shown as prolonged mitochondrial neuronal death. Sodium pyruvate (SP), a substrate of the tricarboxylic acid cycle and an extracellular antioxidant, has been considered as a potential treatment for hypoxic-ischemic encephalopathy (HIE), but its effects have not been evaluated in ...

  2. Erythrocyte pyruvate kinase deficiency in the Ohio Amish: origin and characterization of the mutant enzyme.

    OpenAIRE

    Muir, W A; Beutler, E; Wasson, C

    1984-01-01

    We have identified eight individuals in an Amish population in Geauga County, Ohio, who have a congenital hemolytic anemia and red cell pyruvate kinase (PK) deficiency. The mutant enzyme is a low Km phosphoenolpyruvate (PEP) variant associated with a slower (77.5% of normal) electrophoretic mobility in starch gel. Because of the high consanguinity in this population, we assume the affected individuals are homozygous for the mutant gene. Genealogical records allow us to trace all eight cases b...

  3. Establishment of mitochondrial pyruvate carrier 1 (MPC1) gene knockout mice with preliminary gene function analyses

    Science.gov (United States)

    Li, Xiaoli; Li, Yaqing; Han, Gaoyang; Li, Xiaoran; Ji, Yasai; Fan, Zhirui; Zhong, Yali; Cao, Jing; Zhao, Jing; Mariusz, Goscinski; Zhang, Mingzhi; Wen, Jianguo; Nesland, Jahn M.; Suo, Zhenhe

    2016-01-01

    Pyruvate plays a critical role in the mitochondrial tricarboxylic acid (TCA) cycle, and it is the center product for the synthesis of amino acids, carbohydrates and fatty acids. Pyruvate transported across the inner mitochondrial membrane appears to be essential in anabolic and catabolic intermediary metabolism. The mitochondrial pyruvate carrier (MPC) mounted in the inner membrane of mitochondria serves as the channel to facilitate pyruvate permeating. In mammals, the MPC is formed by two paralogous subunits, MPC1 and MPC2. It is known that complete ablation of MPC2 in mice causes death on the 11th or 12th day of the embryonic period. However, MPC1 deletion and the knowledge of gene function in vivo are lacking. Using the new technology of gene manipulation known as Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated 9 (CRISPR/Cas9) systems, we gained stable MPC1 gene heterozygous mutation mice models, and the heterozygous mutations could be stably maintained in their offsprings. Only one line with homozygous 27 bases deletion in the first exon was established, but no offsprings could be obtained after four months of mating experiments, indicating infertility of the mice with such homozygous deletion. The other line of MPC1 knockout (KO) mice was only heterozygous, which mutated in the first exon with a terminator shortly afterwards. These two lines of MPC1 KO mice showed lower fertility and significantly higher bodyweight in the females. We concluded that heterozygous MPC1 KO weakens fertility and influences the metabolism of glucose and fatty acid and bodyweight in mice. PMID:27835892

  4. Diasporas, transnationalisme et engagement : tamouls et cinghalais ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Diasporas, transnationalisme et engagement : tamouls et cinghalais au Canada et leurs liens avec le Sri Lanka. Ce projet examinera le rôle du financement et des réseaux de la diaspora dans le conflit ethnopolitique au Sri Lanka, en étudiant les réseaux des collectivités transnationales tamoule et cinghalaise au Canada ...

  5. Inoculação com Rhizobium e aplicação de nitrogênio em amendoim Comparison among Rhizobium strains inoculations and nitrogen applications on peanut, in field conditions

    Directory of Open Access Journals (Sweden)

    Antonio Roberto Giardini

    1985-01-01

    Full Text Available Existe, nas nossas condições, uma população autóctone de Rhizobium capaz de nodular o amendoim (Arachis hypogaea L., mas pouco se sabe da contribuição do nitrogênio fixado para esta planta. Foram conduzidos dois ensaios no campo, em solo de baixa fertilidade, um no período "da seca" e outro no "das águas", comparando o crescimento e a produção de plantas de amendoim inoculado com Rhizobium selecionado, com o de plantas noduladas pela população autóctone, adubadas ou não com nitrogênio. A nodulação das plantas inoculadas foi semelhante à observada nos tratamentos não inoculados, com ou sem nitrogênio. Na fase final do ciclo das plantas, houve maior acúmulo e maior taxa de absorção diária de nitrogênio nos tratamentos inoculados ou com adubação nitrogenada, do que no controle sem inoculação e sem nitrogênio. No ensaio da seca, não houve aumento de produção devido à adubação nitrogenada, ou à inoculação. No ensaio das águas, houve resposta à aplicação de nitrogênio no plantio. Os resultados de produção não foram coerentes com os da marcha de absorção de N. A produção de ensaio das águas foi equivalente a 3.400 kg/ha para o tratamento sem nitrogênio e sem inoculação.Two field experiments were carried out with peanut in the same area on a limed and fertilized "cerrado soil" (originally acidic and low fertility. The first experiment was carried out in the autumn/winter (dry season, and the second one in the subsequent spring/summer (wet season, in Campinas, State of São Paulo, Brazil. Plant development and production of inoculated (three Rhizobium strains and nitrogen fertilized treatments (at planting 25 and 45 days after planting were compared with non-inoculated and non-N-fertilized control. Nodulation of inoculated plants was similar to those of non-inoculated, with or without nitrogen. Greater accumulations, and rates for average daily uptake of nitrogen were observed for inoculated as

  6. Beneficial effect of pyruvate therapy on Leigh syndrome due to a novel mutation in PDH E1α gene.

    Science.gov (United States)

    Koga, Yasutoshi; Povalko, Nataliya; Katayama, Koujyu; Kakimoto, Noriko; Matsuishi, Toyojiro; Naito, Etsuo; Tanaka, Masashi

    2012-02-01

    Leigh syndrome (LS) is a progressive untreatable degenerating mitochondrial disorder caused by either mitochondrial or nuclear DNA mutations. A patient was a second child of unconsanguineous parents. On the third day of birth, he was transferred to neonatal intensive care units because of severe lactic acidosis. Since he was showing continuous lactic acidosis, the oral supplementation of dichloroacetate (DCA) was introduced on 31st day of birth at initial dose of 50 mg/kg, followed by maintenance dose of 25 mg/kg/every 12 h. The patient was diagnosed with LS due to a point mutation of an A-C at nucleotide 599 in exon 6 in the pyruvate dehydrogenase E1α gene, resulting in the substitution of aspartate for threonine at position 200 (N200T). Although the concentrations of lactate and pyruvate in blood were slightly decreased, his clinical conditions were deteriorating progressively. In order to overcome the mitochondrial or cytosolic energy crisis indicated by lactic acidosis as well as clinical symptoms, we terminated the DCA and administered 0.5 g/kg/day TID of sodium pyruvate orally. We analyzed the therapeutic effects of DCA or sodium pyruvate in the patient, and found that pyruvate therapy significantly decreased lactate, pyruvate and alanine levels, showed no adverse effects such as severe neuropathy seen in DCA, and had better clinical response on development and epilepsy. Though the efficacy of pyruvate on LS will be evaluated by randomized double-blind placebo-controlled study design in future, pyruvate therapy is a possible candidate for therapeutic choice for currently incurable mitochondrial disorders such as LS. Copyright © 2011 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

  7. Single Sodium Pyruvate Ingestion Modifies Blood Acid-Base Status and Post-Exercise Lactate Concentration in Humans

    Directory of Open Access Journals (Sweden)

    Robert A. Olek

    2014-05-01

    Full Text Available This study examined the effect of a single sodium pyruvate ingestion on a blood acid-base status and exercise metabolism markers. Nine active, but non-specifically trained, male subjects participated in the double-blind, placebo-controlled, crossover study. One hour prior to the exercise, subjects ingested either 0.1 g·kg−1 of body mass of a sodium pyruvate or placebo. The capillary blood samples were obtained at rest, 60 min after ingestion, and then three and 15 min after completing the workout protocol to analyze acid-base status and lactate, pyruvate, alanine, glucose concentrations. The pulmonary gas exchange, minute ventilation and the heart rate were measured during the exercise at a constant power output, corresponding to ~90% O2max. The blood pH, bicarbonate and the base excess were significantly higher after sodium pyruvate ingestion than in the placebo trial. The blood lactate concentration was not different after the ingestion, but the post-exercise was significantly higher in the pyruvate trial (12.9 ± 0.9 mM than in the placebo trial (10.6 ± 0.3 mM, p < 0.05 and remained elevated (nonsignificant after 15 min of recovery. The blood pyruvate, alanine and glucose concentrations, as well as the overall pulmonary gas exchange during the exercise were not affected by the pyruvate ingestion. In conclusion, the sodium pyruvate ingestion one hour before workout modified the blood acid-base status and the lactate production during the exercise.

  8. MCT1 Modulates Cancer Cell Pyruvate Export and Growth of Tumors that Co-express MCT1 and MCT4

    OpenAIRE

    Hong, Candice Sun; Graham, Nicholas A.; Gu, Wen; Espindola Camacho, Carolina; Mah, Vei; Maresh, Erin L.; Alavi, Mohammed; Bagryanova, Lora; Krotee, Pascal A.L.; Gardner, Brian K.; Behbahan, Iman Saramipoor; Horvath, Steve; Chia, David; Mellinghoff, Ingo K.; Hurvitz, Sara A.

    2016-01-01

    Monocarboxylate Transporter 1 (MCT1) inhibition is thought to block tumor growth through disruption of lactate transport and glycolysis. Here we show MCT1 inhibition impairs proliferation of glycolytic breast cancer cells co-expressing MCT1 and MCT4 via disruption of pyruvate rather than lactate export. MCT1 expression is elevated in glycolytic breast tumors, and high MCT1 expression predicts poor prognosis in breast and lung cancer patients. Acute MCT1 inhibition reduces pyruvate export but ...

  9. Molecular and Physiological Logics of the Pyruvate-Induced Response of a Novel Transporter in Bacillus subtilis

    Directory of Open Access Journals (Sweden)

    Teddy Charbonnier

    2017-10-01

    Full Text Available At the heart of central carbon metabolism, pyruvate is a pivotal metabolite in all living cells. Bacillus subtilis is able to excrete pyruvate as well as to use it as the sole carbon source. We herein reveal that ysbAB (renamed pftAB, the only operon specifically induced in pyruvate-grown B. subtilis cells, encodes a hetero-oligomeric membrane complex which operates as a facilitated transport system specific for pyruvate, thereby defining a novel class of transporter. We demonstrate that the LytST two-component system is responsible for the induction of pftAB in the presence of pyruvate by binding of the LytT response regulator to a palindromic region upstream of pftAB. We show that both glucose and malate, the preferred carbon sources for B. subtilis, trigger the binding of CcpA upstream of pftAB, which results in its catabolite repression. However, an additional CcpA-independent mechanism represses pftAB in the presence of malate. Screening a genome-wide transposon mutant library, we find that an active malic enzyme replenishing the pyruvate pool is required for this repression. We next reveal that the higher the influx of pyruvate, the stronger the CcpA-independent repression of pftAB, which suggests that intracellular pyruvate retroinhibits pftAB induction via LytST. Such a retroinhibition challenges the rational design of novel nature-inspired sensors and synthetic switches but undoubtedly offers new possibilities for the development of integrated sensor/controller circuitry. Overall, we provide evidence for a complete system of sensors, feed-forward and feedback controllers that play a major role in environmental growth of B. subtilis.

  10. Volumetric spiral chemical shift imaging of hyperpolarized [2-(13) c]pyruvate in a rat c6 glioma model.

    Science.gov (United States)

    Park, Jae Mo; Josan, Sonal; Jang, Taichang; Merchant, Milton; Watkins, Ron; Hurd, Ralph E; Recht, Lawrence D; Mayer, Dirk; Spielman, Daniel M

    2016-03-01

    MRS of hyperpolarized [2-(13)C]pyruvate can be used to assess multiple metabolic pathways within mitochondria as the (13)C label is not lost with the conversion of pyruvate to acetyl-CoA. This study presents the first MR spectroscopic imaging of hyperpolarized [2-(13)C]pyruvate in glioma-bearing brain. Spiral chemical shift imaging with spectrally undersampling scheme (1042 Hz) and a hard-pulse excitation was exploited to simultaneously image [2-(13)C]pyruvate, [2-(13)C]lactate, and [5-(13)C]glutamate, the metabolites known to be produced in brain after an injection of hyperpolarized [2-(13)C]pyruvate, without chemical shift displacement artifacts. A separate undersampling scheme (890 Hz) was also used to image [1-(13)C]acetyl-carnitine. Healthy and C6 glioma-implanted rat brains were imaged at baseline and after dichloroacetate administration, a drug that modulates pyruvate dehydrogenase kinase activity. The baseline metabolite maps showed higher lactate and lower glutamate in tumor as compared to normal-appearing brain. Dichloroacetate led to an increase in glutamate in both tumor and normal-appearing brain. Dichloroacetate-induced %-decrease of lactate/glutamate was comparable to the lactate/bicarbonate decrease from hyperpolarized [1-(13)C]pyruvate studies. Acetyl-carnitine was observed in the muscle/fat tissue surrounding the brain. Robust volumetric imaging with hyperpolarized [2-(13)C]pyruvate and downstream products was performed in glioma-bearing rat brains, demonstrating changes in mitochondrial metabolism with dichloroacetate. © 2015 Wiley Periodicals, Inc.

  11. Monitoring Mitochondrial Pyruvate Carrier Activity in Real Time Using a BRET-Based Biosensor: Investigation of the Warburg Effect

    OpenAIRE

    Compan V; Pierredon S; Vanderperre B; Krznar P; Marchiq I; Zamboni N; Pouyssegur J; Martinou JC

    2015-01-01

    The transport of pyruvate into mitochondria requires a specific carrier the mitochondrial pyruvate carrier (MPC). The MPC represents a central node of carbon metabolism and its activity is likely to play a key role in bioenergetics. Until now investigation of the MPC activity has been limited. However the recent molecular identification of the components of the carrier has allowed us to engineer a genetically encoded biosensor and to monitor the activity of the MPC in real time in a cell popu...

  12. MPC1-like Is a Placental Mammal-specific Mitochondrial Pyruvate Carrier Subunit Expressed in Postmeiotic Male Germ Cells

    OpenAIRE

    Vanderperre, Benoît; Cermakova, Kristina; Escoffier Breancon, Jessica; Kaba, Mayis; Bender, Tom; Nef, Serge; Martinou, Jean-Claude

    2016-01-01

    Selective transport of pyruvate across the inner mitochondrial membrane by the mitochondrial pyruvate carrier (MPC) is a fundamental step that couples cytosolic and mitochondrial metabolism. The recent molecular identification of the MPC complex has revealed two interacting subunits, MPC1 and MPC2. Although in yeast, an additional subunit, MPC3, can functionally replace MPC2, no alternative MPC subunits have been described in higher eukaryotes. Here, we report for the first time the existence...

  13. Breast Cancer-Derived Lung Metastases Show Increased Pyruvate Carboxylase-Dependent Anaplerosis

    Directory of Open Access Journals (Sweden)

    Stefan Christen

    2016-10-01

    Full Text Available Cellular proliferation depends on refilling the tricarboxylic acid (TCA cycle to support biomass production (anaplerosis. The two major anaplerotic pathways in cells are pyruvate conversion to oxaloacetate via pyruvate carboxylase (PC and glutamine conversion to α-ketoglutarate. Cancers often show an organ-specific reliance on either pathway. However, it remains unknown whether they adapt their mode of anaplerosis when metastasizing to a distant organ. We measured PC-dependent anaplerosis in breast-cancer-derived lung metastases compared to their primary cancers using in vivo 13C tracer analysis. We discovered that lung metastases have higher PC-dependent anaplerosis compared to primary breast cancers. Based on in vitro analysis and a mathematical model for the determination of compartment-specific metabolite concentrations, we found that mitochondrial pyruvate concentrations can promote PC-dependent anaplerosis via enzyme kinetics. In conclusion, we show that breast cancer cells proliferating as lung metastases activate PC-dependent anaplerosis in response to the lung microenvironment.

  14. Kinetic and Thermodynamic Analysis of Acetyl-CoA Activation of Staphylococcus aureus Pyruvate Carboxylase.

    Science.gov (United States)

    Westerhold, Lauren E; Bridges, Lance C; Shaikh, Saame Raza; Zeczycki, Tonya N

    2017-07-11

    Allosteric regulation of pyruvate carboxylase (PC) activity is pivotal to maintaining metabolic homeostasis. In contrast, dysregulated PC activity contributes to the pathogenesis of numerous diseases, rendering PC a possible target for allosteric therapeutic development. Recent research efforts have focused on demarcating the role of acetyl-CoA, one of the most potent activators of PC, in coordinating catalytic events within the multifunctional enzyme. Herein, we report a kinetic and thermodynamic analysis of acetyl-CoA activation of the Staphylococcus aureus PC (SaPC)-catalyzed carboxylation of pyruvate to identify novel means by which acetyl-CoA synchronizes catalytic events within the PC tetramer. Kinetic and linked-function analysis, or thermodynamic linkage analysis, indicates that the substrates of the biotin carboxylase and carboxyl transferase domain are energetically coupled in the presence of acetyl-CoA. In contrast, both kinetic and energetic coupling between the two domains is lost in the absence of acetyl-CoA, suggesting a functional role for acetyl-CoA in facilitating the long-range transmission of substrate-induced conformational changes within the PC tetramer. Interestingly, thermodynamic activation parameters for the SaPC-catalyzed carboxylation of pyruvate are largely independent of acetyl-CoA. Our results also reveal the possibility that global conformational changes give rise to observed species-specific thermodynamic activation parameters. Taken together, our kinetic and thermodynamic results provide a possible allosteric mechanism by which acetyl-CoA coordinates catalysis within the PC tetramer.

  15. Stem Cell Metabolism in Cancer and Healthy Tissues: Pyruvate in the Limelight

    Directory of Open Access Journals (Sweden)

    Cyril Corbet

    2018-01-01

    Full Text Available Normal and cancer stem cells (CSCs share the remarkable potential to self-renew and differentiate into many distinct cell types. Although most of the stem cells remain under quiescence to maintain their undifferentiated state, they can also undergo cell divisions as required to regulate tissue homeostasis. There is now a growing evidence that cell fate determination from stem cells implies a fine-tuned regulation of their energy balance and metabolic status. Stem cells can shift their metabolic substrate utilization, between glycolysis and mitochondrial oxidative metabolism, during specification and/or differentiation, as well as in order to adapt their microenvironmental niche. Pyruvate appears as a key metabolite since it is at the crossroads of cytoplasmic glycolysis and mitochondrial oxidative phosphorylation. This Review describes how metabolic reprogramming, focusing on pyruvate utilization, drives the fate of normal and CSCs by modulating their capacity for self-renewal, clonal expansion/differentiation, as well as metastatic potential and treatment resistance in cancer. This Review also explores potential therapeutic strategies to restore or manipulate stem cell function through the use of small molecules targeting the pyruvate metabolism.

  16. Increased production of pyruvic acid by Escherichia coli RNase G mutants in combination with cra mutations.

    Science.gov (United States)

    Sakai, Taro; Nakamura, Naoko; Umitsuki, Genryou; Nagai, Kazuo; Wachi, Masaaki

    2007-08-01

    The Escherichia coli RNase G is known as an endoribonuclease responsible for the 5'-end maturation of 16S rRNA and degradation of several specific mRNAs such as adhE and eno mRNAs. In this study, we found that an RNase G mutant derived from the MC1061 strain did not grow on a glucose minimal medium. Genetic analysis revealed that simultaneous defects of cra and ilvIH, encoding a transcriptional regulator of glycolysis/gluconeogenesis and one of isozymes of acetohydroxy acid synthase, respectively, were required for this phenomenon to occur. The results of additional experiments presented here indicate that the RNase G mutation, in combination with cra mutation, caused the increased production of pyruvic acid from glucose, which was then preferentially converted to valine due to the ilvIH mutation, resulting in depletion of isoleucine. In fact, the rng cra double mutant produced increased amount of pyruvate in the medium. These results suggest that the RNase G mutation could be applied in the breeding of producer strains of pyruvate and its derivatives such as valine.

  17. Pyruvate cycle increases aminoglycoside efficacy and provides respiratory energy in bacteria.

    Science.gov (United States)

    Su, Yu-Bin; Peng, Bo; Li, Hui; Cheng, Zhi-Xue; Zhang, Tian-Tuo; Zhu, Jia-Xin; Li, Dan; Li, Min-Yi; Ye, Jin-Zhou; Du, Chao-Chao; Zhang, Song; Zhao, Xian-Liang; Yang, Man-Jun; Peng, Xuan-Xian

    2018-02-13

    The emergence and ongoing spread of multidrug-resistant bacteria puts humans and other species at risk for potentially lethal infections. Thus, novel antibiotics or alternative approaches are needed to target drug-resistant bacteria, and metabolic modulation has been documented to improve antibiotic efficacy, but the relevant metabolic mechanisms require more studies. Here, we show that glutamate potentiates aminoglycoside antibiotics, resulting in improved elimination of antibiotic-resistant pathogens. When exploring the metabolic flux of glutamate, it was found that the enzymes that link the phosphoenolpyruvate (PEP)-pyruvate-AcCoA pathway to the TCA cycle were key players in this increased efficacy. Together, the PEP-pyruvate-AcCoA pathway and TCA cycle can be considered the pyruvate cycle (P cycle). Our results show that inhibition or gene depletion of the enzymes in the P cycle shut down the TCA cycle even in the presence of excess carbon sources, and that the P cycle operates routinely as a general mechanism for energy production and regulation in Escherichia coli and Edwardsiella tarda These findings address metabolic mechanisms of metabolite-induced potentiation and fundamental questions about bacterial biochemistry and energy metabolism.

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

    Science.gov (United States)

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

    1983-07-01

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

  19. Study on the protective effect of ethyl pyruvate on mouse models of sepsis-induced lung injury

    International Nuclear Information System (INIS)

    Ti Dongdong; Deng Zihui; Xue Hui; Wang Luhuan; Lin Ji; Yan Guangtao

    2008-01-01

    Objective: To investigate the protective role of ethyl pyruvate on mouse models of lung injury from sepsis. Methods: Mouse sepsis models were established by cecal ligation-perforation. Four enzyme parameters related to synthesis of free radicals in lung homogenized fluids namely malonaldehyde (MDA), pyruvate acid, lactic acid and total anti-oxidative capacity (TAOC) were determined with spectrophotometry, and serum leptin levels were detected with radioimmunoassay at 3, 6, 9, 12h after operation in these models. Half of the models were treated with intraperitoneal injection of ethyl pyruvate (EP) (75mg/kg). Results: In the models treated with ethyl pyruvate injection, the activity of malonaldehyde, pyruvate acid, lactic acid and total anti-oxidative capacity were affected to certain extent, at some time frames but the results were not unanimously inhibitive or promotive. Serum leptin levels in EP injection models at 6h and 12h after sepsis were significantly higher than those in non-treated models. Conclusion: Ethyl pyruvate perhaps exerted its protective effect on sepsis-induced lung injury through increase of leptin levels in the models. (authors)

  20. Novel binding motif and new flexibility revealed by structural analyses of a pyruvate dehydrogenase-dihydrolipoyl acetyltransferase subcomplex from the Escherichia coli pyruvate dehydrogenase multienzyme complex.

    Science.gov (United States)

    Arjunan, Palaniappa; Wang, Junjie; Nemeria, Natalia S; Reynolds, Shelley; Brown, Ian; Chandrasekhar, Krishnamoorthy; Calero, Guillermo; Jordan, Frank; Furey, William

    2014-10-24

    The Escherichia coli pyruvate dehydrogenase multienzyme complex contains multiple copies of three enzymatic components, E1p, E2p, and E3, that sequentially carry out distinct steps in the overall reaction converting pyruvate to acetyl-CoA. Efficient functioning requires the enzymatic components to assemble into a large complex, the integrity of which is maintained by tethering of the displaced, peripheral E1p and E3 components to the E2p core through non-covalent binding. We here report the crystal structure of a subcomplex between E1p and an E2p didomain containing a hybrid lipoyl domain along with the peripheral subunit-binding domain responsible for tethering to the core. In the structure, a region at the N terminus of each subunit in the E1p homodimer previously unseen due to crystallographic disorder was observed, revealing a new folding motif involved in E1p-E2p didomain interactions, and an additional, unexpected, flexibility was discovered in the E1p-E2p didomain subcomplex, both of which probably have consequences in the overall multienzyme complex assembly. This represents the first structure of an E1p-E2p didomain subcomplex involving a homodimeric E1p, and the results may be applicable to a large range of complexes with homodimeric E1 components. Results of HD exchange mass spectrometric experiments using the intact, wild type 3-lipoyl E2p and E1p are consistent with the crystallographic data obtained from the E1p-E2p didomain subcomplex as well as with other biochemical and NMR data reported from our groups, confirming that our findings are applicable to the entire E1p-E2p assembly. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  1. Novel Binding Motif and New Flexibility Revealed by Structural Analyses of a Pyruvate Dehydrogenase-Dihydrolipoyl Acetyltransferase Subcomplex from the Escherichia coli Pyruvate Dehydrogenase Multienzyme Complex*

    Science.gov (United States)

    Arjunan, Palaniappa; Wang, Junjie; Nemeria, Natalia S.; Reynolds, Shelley; Brown, Ian; Chandrasekhar, Krishnamoorthy; Calero, Guillermo; Jordan, Frank; Furey, William

    2014-01-01

    The Escherichia coli pyruvate dehydrogenase multienzyme complex contains multiple copies of three enzymatic components, E1p, E2p, and E3, that sequentially carry out distinct steps in the overall reaction converting pyruvate to acetyl-CoA. Efficient functioning requires the enzymatic components to assemble into a large complex, the integrity of which is maintained by tethering of the displaced, peripheral E1p and E3 components to the E2p core through non-covalent binding. We here report the crystal structure of a subcomplex between E1p and an E2p didomain containing a hybrid lipoyl domain along with the peripheral subunit-binding domain responsible for tethering to the core. In the structure, a region at the N terminus of each subunit in the E1p homodimer previously unseen due to crystallographic disorder was observed, revealing a new folding motif involved in E1p-E2p didomain interactions, and an additional, unexpected, flexibility was discovered in the E1p-E2p didomain subcomplex, both of which probably have consequences in the overall multienzyme complex assembly. This represents the first structure of an E1p-E2p didomain subcomplex involving a homodimeric E1p, and the results may be applicable to a large range of complexes with homodimeric E1 components. Results of HD exchange mass spectrometric experiments using the intact, wild type 3-lipoyl E2p and E1p are consistent with the crystallographic data obtained from the E1p-E2p didomain subcomplex as well as with other biochemical and NMR data reported from our groups, confirming that our findings are applicable to the entire E1p-E2p assembly. PMID:25210042

  2. The Role of Teak Leaves (Tectona grandis), Rhizobium, and Vesicular-Arbuscular Mycorrhizae on Improving Soil Structure and Soil Nutrition

    Science.gov (United States)

    Yuliani; Rahayu, Y. S.

    2018-01-01

    Calcium is the largest mineral in calcareous soils. High levels of calcium carbonate lead to phosphate deposition. Nutrient deficiencies in calcareous soil (mainly Phosphate and Nitrogen) resulted only certain crops with a wide range of tolerances that can grow. Meanwhile, dynamics nutrient in calcareous soils also depend on the topography and decomposition of the litter in the growing vegetation. The purpose of this study was to describe the pattern of nutrient enhancement and soil-texture structures on calcareous soils after littering the teak leaves, Rhizobium and Vesicular Arbuscular Mycorrhiza. The research parameters were the concentration of N, P, K; C/N ratio, humid acid content, and soil structure, which measured at days 30, 60, and 85 of soil decomposition process. The results showed that at days 30, the texture and structure of the soil tend to be stable (porosity 31.2, DMR 1.93, moisture content 0.36, sandy clay) while at days 85 has been very stable (porosity 49.8; Water content 0.28, sandy clay). While C and N organic, N and K concentration at days 30 showed low value (C organic 1.03, N 0.12, K 0.49, C / N ratio 9). This condition is almost unchanged at days 85. While the P value shows very high value (60.53) at days 30 although after 60 days the P content showed a decrease.

  3. Enhanced Synthesis of Antioxidant Enzymes, Defense Proteins and Leghemoglobin in Rhizobium-Free Cowpea Roots after Challenging with Meloydogine incognita

    Directory of Open Access Journals (Sweden)

    Jose T. A. Oliveira

    2014-11-01

    Full Text Available The root knot nematodes (RKN, Meloydogine spp., particularly Meloidogyne incognita and Meloidogyne javanica species, parasitize several plant species and are responsible for large annual yield losses all over the world. Only a few available chemical nematicides are still authorized for RKN control owing to environmental and health reasons. Thus, plant resistance is currently considered the method of choice for controlling RKN, and research performed on the molecular interactions between plants and nematodes to identify genes of interest is of paramount importance. The present work aimed to identify the differential accumulation of root proteins of a resistant cowpea genotype (CE-31 inoculated with M. incognita (Race 3 in comparison with mock-inoculated control, using 2D electrophoresis assay, mass spectrometry identification and gene expression analyses by RT-PCR. The results showed that at least 22 proteins were differentially represented in response to RKN challenge of cowpea roots mainly within 4–6 days after inoculation. Amongst the up-represented proteins were SOD, APX, PR-1, β-1,3-glucanase, chitinases, cysteine protease, secondary metabolism enzymes, key enzymes involved in ethylene biosynthesis, proteins involved in MAPK pathway signaling and, surprisingly, leghemoglobin in non-rhizobium-bacterized cowpea. These findings show that an important rearrangement in the resistant cowpea root proteome occurred following challenge with M. incognita.

  4. A model for the catabolism of rhizopine in Rhizobium leguminosarum involves a ferredoxin oxygenase complex and the inositol degradative pathway.

    Science.gov (United States)

    Bahar, M; de Majnik, J; Wexler, M; Fry, J; Poole, P S; Murphy, P J

    1998-11-01

    Rhizopines are nodule-specific compounds that confer an intraspecies competitive nodulation advantage to strains that can catabolize them. The rhizopine (3-O-methyl-scyllo-inosamine, 3-O-MSI) catabolic moc gene cluster mocCABRDE(F) in Rhizobium leguminosarum bv. viciae strain 1a is located on the Sym plasmid. MocCABR are homologous to the mocCABR gene products from Sinorhizobium meliloti. MocD and MocE contain motifs corresponding to a TOL-like oxygenase and a [2Fe-2S] Rieske-like ferredoxin, respectively. The mocF gene encodes a ferredoxin reductase that would complete the oxygenase system, but is not essential for rhizopine catabolism. We propose a rhizopine catabolic model whereby MocB transports rhizopine into the cell and MocDE and MocF (or a similar protein elsewhere in the genome), under the regulation of MocR, act in concert to form a ferredoxin oxygenase system that demethylates 3-O-MSI to form scyllo-inosamine (SI). MocA, an NAD(H)-dependent dehydrogenase, and MocC continue the catabolic process. Compounds formed then enter the inositol catabolic pathway.

  5. Molecular and genetic characterization of the rhizopine catabolism (mocABRC) genes of Rhizobium meliloti L5-30.

    Science.gov (United States)

    Rossbach, S; Kulpa, D A; Rossbach, U; de Bruijn, F J

    1994-10-17

    Rhizopine (L-3-O-methyl-scyllo-inosamine, 3-O-MSI) is a symbiosis-specific compound, which is synthesized in nitrogen-fixing nodules of Medicago sativa induced by Rhizobium meliloti strain L5-30. 3-O-MSI is thought to function as an unusual growth substrate for R. meliloti L5-30, which carries a locus (mos) responsible for its synthesis closely linked to a locus (moc) responsible for its degradation. Here, the essential moc genes were delimited by Tn5 mutagenesis and shown to be organized into two regions, separated by 3 kb of DNA. The DNA sequence of a 9-kb fragment spanning the two moc regions was determined, and four genes were identified that play an essential role in rhizopine catabolism (mocABC and mocR). The analysis of the DNA sequence and the amino acid sequence of the deduced protein products revealed that MocA resembles NADH-dependent dehydrogenases. MocB exhibits characteristic features of periplasmic-binding proteins that are components of high-affinity transport systems. MocC does not share significant homology with any protein in the database. MocR shows homology with the GntR class of bacterial regulator proteins. These results suggest that the mocABC genes are involved in the uptake and subsequent degradation of rhizopine, whereas mocR is likely to play a regulatory role.

  6. Cloning and characterization of a galactitol 2-dehydrogenase from Rhizobium legumenosarum and its application in D-tagatose production.

    Science.gov (United States)

    Jagtap, Sujit Sadashiv; Singh, Ranjitha; Kang, Yun Chan; Zhao, Huimin; Lee, Jung-Kul

    2014-05-10

    Galactitol 2-dehydrogenase (GDH) belongs to the protein subfamily of short-chain dehydrogenases/reductases and can be used to produce optically pure building blocks and for the bioconversion of bioactive compounds. An NAD(+)-dependent GDH from Rhizobium leguminosarum bv. viciae 3841 (RlGDH) was cloned and overexpressed in Escherichia coli. The RlGDH protein was purified as an active soluble form using His-tag affinity chromatography. The molecular mass of the purified enzyme was estimated to be 28kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and 114kDa by gel filtration chromatography, suggesting that the enzyme is a homotetramer. The enzyme has an optimal pH and temperature of 9.5 and 35°C, respectively. The purified recombinant RlGDH catalyzed the oxidation of a wide range of substrates, including polyvalent aliphatic alcohols and polyols, to the corresponding ketones and ketoses. Among various polyols, galactitol was the preferred substrate of RlGDH with a Km of 8.8mM, kcat of 835min(-1) and a kcat/Km of 94.9min(-1)mM(-1). Although GDHs have been characterized from a few other sources, RlGDH is distinguished from other GDHs by its higher specific activity for galactitol and broad substrate spectrum, making RlGDH a good choice for practical applications. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. Biologic fixation of nitrogen in irradiated rhizobium strips; Fixacao biologica do nitrogenio em estirpes de rizobianas irradiadas

    Energy Technology Data Exchange (ETDEWEB)

    Caribe, Rebeka Alves; Colaco, Waldeciro [Pernambuco Univ., Recife, PE (Brazil). Dept. de Energia Nuclear

    2002-07-01

    Native Rhizobium sp. and Bradyrhizobium sp. isolates from the root nodules of bean and cowpea were selected. Six isolates, and the SEMIA 4077 (R. leguminosarum bv. phaseolus) and SEMIA 6145 (Bradyrhizobium sp) strains used as references, were irradiated with ultraviolet light (R-uv) and gamma rays (R-{gamma}). The D{sub 37} values for the rhizobial strain SEMIA 4077 were 43 J.m{sup -2} (UV) and 32 Gy (R-{gamma}) and for the SEMIA 6145 were 45 J.m{sup -2} (UV) and 35 Gy (R-gamma). Through a greenhouse experiment the irradiated isolates were inoculated on bean (P. vulgaris L., cv. Princesa) and on cowpea [Vigna unguiculata, (L.) Walp, cv. IPA-206] seedlings, in an attempt to evaluate the sensitivity of the host plants, and possible effects on their nodulation. Differences in responses to nodulation due to the effect of irradiation were observed for the isolates tested. Significantly differences were observed only for nodules dry matter yield of the IPA-206 cultivar. Gamma irradiated treatment were statistically superior to treatments with ultraviolet light in relation. (author)

  8. Characterisation of SalRAB a salicylic acid inducible positively regulated efflux system of Rhizobium leguminosarum bv viciae 3841.

    Directory of Open Access Journals (Sweden)

    Adrian J Tett

    Full Text Available Salicylic acid is an important signalling molecule in plant-microbe defence and symbiosis. We analysed the transcriptional responses of the nitrogen fixing plant symbiont, Rhizobium leguminosarum bv viciae 3841 to salicylic acid. Two MFS-type multicomponent efflux systems were induced in response to salicylic acid, rmrAB and the hitherto undescribed system salRAB. Based on sequence similarity salA and salB encode a membrane fusion and inner membrane protein respectively. salAB are positively regulated by the LysR regulator SalR. Disruption of salA significantly increased the sensitivity of the mutant to salicylic acid, while disruption of rmrA did not. A salA/rmrA double mutation did not have increased sensitivity relative to the salA mutant. Pea plants nodulated by salA or rmrA strains did not have altered nodule number or nitrogen fixation rates, consistent with weak expression of salA in the rhizosphere and in nodule bacteria. However, BLAST analysis revealed seventeen putative efflux systems in Rlv3841 and several of these were highly differentially expressed during rhizosphere colonisation, host infection and bacteroid differentiation. This suggests they have an integral role in symbiosis with host plants.

  9. Effect of N-rate and P sources on BNF in soybean as affected by rhizobium and VAM fungi lnoculants

    Energy Technology Data Exchange (ETDEWEB)

    Soliman, S; Elghandour, I A [Soil and Water Dept., Atomic Energy Authority, Cairo, (Egypt); Abbady, A K [Soil and Water Inst., Agric. Res. Center, Giza (Egypt)

    1995-10-01

    Greenhouse experiment was made to investigate the influence of phosphate fertilizers on nitrogen fixation in soybean. The N-15 isotope dilution method was used to quantify N 2-fixed. In this concern, seed of nodulated and on-nodulated soybean plant bacterized with Bradyrhizobium japonicum and noculated without or with mycorrhizas in the presence of super or rock phosphate. Ammonium sulphate labelled fertilizer (5% N-15 a.e) was applied o 15 kg sandy soil of egypt at the rate of 20 and 100 kg N/acre. At re-flowering stage, the highest amount of N derived from air (Ndfa) was 66.3 and 470.2 (mg/pot) equivalent 47.6 and 47.1 of total N assimilated for noculated soybean with Rhizobium and fertilized with super or rock phosphate, respectively. While the contributions from 15 N labelled fertilizer (Ndff) accounted for 11 and 10.8, respectively. Use of mycorrhizas could increase the amount of N 2-fixed in the presence of rhizobia. There appears to be a strong case for improving N 2-fixation in the presence of mycorrhizas especially in sandy soil. 4 tabs.

  10. Extended region of nodulation genes in Rhizobium meliloti 1021. II. Nucleotide sequence, transcription start sites and protein products

    International Nuclear Information System (INIS)

    Fisher, R.F.; Swanson, J.A.; Mulligan, J.T.; Long, S.R.

    1987-01-01

    The authors have established the DNA sequence and analyzed the transcription and translation products of a series of putative nodulation (nod) genes in Rhizobium meliloti strain 1021. Four loci have been designated nodF, nodE, nodG and nodH. The correlation of transposon insertion positions with phenotypes and open reading frames was confirmed by sequencing the insertion junctions of the transposons. The protein products of these nod genes were visualized by in vitro expression of cloned DNA segments in a R. meliloti transcription-translation system. In addition, the sequence for nodG was substantiated by creating translational fusions in all three reading frames at several points in the sequence; the resulting fusions were expressed in vitro in both E. coli and R. meliloti transcription-translation systems. A DNA segment bearing several open reading frames downstream of nodG corresponds to the putative nod gene mutated in strain nod-216. The transcription start sites of nodF and nodH were mapped by primer extension of RNA from cells induced with the plant flavone, luteolin. Initiation of transcription occurs approximately 25 bp downstream from the conserved sequence designated the nod box, suggesting that this conserved sequence acts as an upstream regulator of inducible nod gene expression. Its distance from the transcription start site is more suggestive of an activator binding site rather than an RNA polymerase binding site

  11. Effect of N-rate and P sources on BNF in soybean as affected by rhizobium and VAM fungi lnoculants

    International Nuclear Information System (INIS)

    Soliman, S.; Elghandour, I.A.; Abbady, A.K.

    1995-01-01

    Greenhouse experiment was made to investigate the influence of phosphate fertilizers on nitrogen fixation in soybean. The N-15 isotope dilution method was used to quantify N 2-fixed. In this concern, seed of nodulated and on-nodulated soybean plant bacterized with Bradyrhizobium japonicum and noculated without or with mycorrhizas in the presence of super or rock phosphate. Ammonium sulphate labelled fertilizer (5% N-15 a.e) was applied o 15 kg sandy soil of egypt at the rate of 20 and 100 kg N/acre. At re-flowering stage, the highest amount of N derived from air (Ndfa) was 66.3 and 470.2 (mg/pot) equivalent 47.6 and 47.1 of total N assimilated for noculated soybean with Rhizobium and fertilized with super or rock phosphate, respectively. While the contributions from 15 N labelled fertilizer (Ndff) accounted for 11 and 10.8, respectively. Use of mycorrhizas could increase the amount of N 2-fixed in the presence of rhizobia. There appears to be a strong case for improving N 2-fixation in the presence of mycorrhizas especially in sandy soil. 4 tabs

  12. Genetic Diversity among Rhizobium leguminosarum bv. Trifolii Strains Revealed by Allozyme and Restriction Fragment Length Polymorphism Analyses

    Science.gov (United States)

    Demezas, David H.; Reardon, Terry B.; Watson, John M.; Gibson, Alan H.

    1991-01-01

    Allozyme electrophoresis and restriction fragment length polymorphism (RFLP) analyses were used to examine the genetic diversity of a collection of 18 Rhizobium leguminosarum bv. trifolii, 1 R. leguminosarum bv. viciae, and 2 R. meliloti strains. Allozyme analysis at 28 loci revealed 16 electrophoretic types. The mean genetic distance between electrophoretic types of R. leguminosarum and R. meliloti was 0.83. Within R. leguminosarum, the single strain of bv. viciae differed at an average of 0.65 from strains of bv. trifolii, while electrophoretic types of bv. trifolii differed at a range of 0.23 to 0.62. Analysis of RFLPs around two chromosomal DNA probes also delineated 16 unique RFLP patterns and yielded genetic diversity similar to that revealed by the allozyme data. Analysis of RFLPs around three Sym (symbiotic) plasmid-derived probes demonstrated that the Sym plasmids reflect genetic divergence similar to that of their bacterial hosts. The large genetic distances between many strains precluded reliable estimates of their genetic relationships. PMID:16348600

  13. Toxicity testing of heavy metals with the Rhizobium-legume symbiosis: high sensitivity to cadmium and arsenic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Neumann, H.; Bode-Kirchhoff, A.; Madeheim, A.; Wetzel, A. [Marburg Univ. (Germany). Fachbereich Biologie

    1998-07-01

    We present data that the formation of nodules (nodulation) may serve for ecotoxicological evaluation of heavy metals in different binding states. Tests were performed in petri dishes with alfalfa (lucerne) seedlings inoculated with Rhizobium meliloti. Cultivation took place in growth cabinets with carefully standardized and documented growth conditions. Data from stressed plants was recorded after 14 days of cultivation on contaminated substrate. A dose responsive decrease in nodulation was found after application of cadmium acetate, cadmium iodide, cadmium chloride, sodium salts of arsenate and arsenite, arsenic pentoxide, and lead nitrate, whereas lead acetate showed no effect up to a concentration of 3 {mu}M. The dose response curves were used to calculate EC10, EC50 and EC90 values. EC50 values for cadmium compounds range from 1.5 to 9.5 {mu}M. Testing different arsenic compounds results in EC50 from 2.6 to 20.1 {mu}M. EC50 of lead nitrate is 2.2 {mu}M. The sensitivity, reproducibility and reliability of this test system is discussed compared to established biotests. (orig./MG)

  14. Hyperpolarized [1-(13) C]pyruvate MRI for noninvasive examination of placental metabolism and nutrient transport: A feasibility study in pregnant guinea pigs.

    Science.gov (United States)

    Friesen-Waldner, Lanette J; Sinclair, Kevin J; Wade, Trevor P; Michael, Banoub; Chen, Albert P; de Vrijer, Barbra; Regnault, Timothy R H; McKenzie, Charles A

    2016-03-01

    To test the feasibility of hyperpolarized [1-(13) C]pyruvate magnetic resonance imaging (MRI) for noninvasive examination of guinea pig fetoplacental metabolism and nutrient transport. Seven pregnant guinea pigs with a total of 30 placentae and fetuses were anesthetized and scanned at 3T. T1 -weighted (1) H images were obtained from the maternal abdomen. An 80 mM solution of hyperpolarized [1-(13) C]pyruvate (hereafter referred to as pyruvate) was injected into a vein in the maternal foot. Time-resolved 3D (13) C images were acquired starting 10 seconds after the beginning of bolus injection and every 10 seconds after to 50 seconds. The pregnant guinea pigs were recovered after imaging. Regions of interest (ROIs) were drawn around the maternal heart and each placenta and fetal liver in all slices in the (1) H images. These ROIs were copied to the (13) C images and were used to calculate the sum of the pyruvate and lactate signal intensities for each organ. The signal intensities were normalized by the volume of the organ and the maximum signal in the maternal heart. No adverse events were observed in the pregnant guinea pigs and natural pupping occurred at term (∼68 days). Pyruvate signal was observed in all 30 placentae, and lactate, a by-product of pyruvate metabolism, was also observed in all placentae. The maximum pyruvate and lactate signals in placentae occurred at 20 seconds. In addition to the observation of pyruvate and lactate signals in the placentae, both pyruvate and lactate signals were observed in all fetal livers. The maximum pyruvate and lactate signals in the fetal livers occurred at 10 seconds and 20 seconds, respectively. This work demonstrates the feasibility of using hyperpolarized [1-(13) C]pyruvate MRI to noninvasively examine fetoplacental metabolism and transport of pyruvate in guinea pigs. Hyperpolarized (13) C MRI may provide a novel method for longitudinal studies of fetoplacental abnormalities. © 2015 Wiley Periodicals, Inc.

  15. Combined Hyperpolarized 13C-pyruvate MRS and 18F-FDG PET (HyperPET) Estimates of Glycolysis in Canine Cancer Patients

    DEFF Research Database (Denmark)

    Hansen, Adam E.; Gutte, Henrik; Holst, Pernille

    2018-01-01

    13C Magnetic Resonance Spectroscopy (MRS) using hyperpolarized 13C-labeled pyruvate as a substrate offers a measure of pyruvate-lactate interconversion and is thereby a marker of the elevated aerobic glycolysis (Warburg effect) generally exhibited by cancer cells. Here, we aim to compare hyperpol......13C Magnetic Resonance Spectroscopy (MRS) using hyperpolarized 13C-labeled pyruvate as a substrate offers a measure of pyruvate-lactate interconversion and is thereby a marker of the elevated aerobic glycolysis (Warburg effect) generally exhibited by cancer cells. Here, we aim to compare...

  16. Transcriptomic profiling of Burkholderia phymatum STM815, Cupriavidus taiwanensis LMG19424 and Rhizobium mesoamericanum STM3625 in response to Mimosa pudica root exudates illuminates the molecular basis of their nodulation competitiveness and symbiotic evolutionary history.

    Science.gov (United States)

    Klonowska, Agnieszka; Melkonian, Rémy; Miché, Lucie; Tisseyre, Pierre; Moulin, Lionel

    2018-01-30

    Rhizobial symbionts belong to the classes Alphaproteobacteria and Betaproteobacteria (called "alpha" and "beta"-rhizobia). Most knowledge on the genetic basis of symbiosis is based on model strains belonging to alpha-rhizobia. Mimosa pudica is a legume that offers an excellent opportunity to study the adaptation toward symbiotic nitrogen fixation in beta-rhizobia compared to alpha-rhizobia. In a previous study (Melkonian et al., Environ Microbiol 16:2099-111, 2014) we described the symbiotic competitiveness of M. pudica symbionts belonging to Burkholderia, Cupriavidus and Rhizobium species. In this article we present a comparative analysis of the transcriptomes (by RNAseq) of B. phymatum STM815 (BP), C. taiwanensis LMG19424 (CT) and R. mesoamericanum STM3625 (RM) in conditions mimicking the early steps of symbiosis (i.e. perception of root exudates). BP exhibited the strongest transcriptome shift both quantitatively and qualitatively, which mirrors its high competitiveness in the early steps of symbiosis and its ancient evolutionary history as a symbiont, while CT had a minimal response which correlates with its status as a younger symbiont (probably via acquisition of symbiotic genes from a Burkholderia ancestor) and RM had a typical response of Alphaproteobacterial rhizospheric bacteria. Interestingly, the upregulation of nodulation genes was the only common response among the three strains; the exception was an up-regulated gene encoding a putative fatty acid hydroxylase, which appears to be a novel symbiotic gene specific to Mimosa symbionts. The transcriptional response to root exudates was correlated to each strain nodulation competitiveness, with Burkholderia phymatum appearing as the best specialised symbiont of Mimosa pudica.

  17. Comparison the effectiveness of pyruvic acid 50% and salicylic acid 30% in the treatment of acne

    Directory of Open Access Journals (Sweden)

    Fariba Jaffary

    2016-01-01

    Full Text Available Background: Acne vulgaris is a chronic inflammatory disease of the pilosebaceous follicles and one of the most common skin diseases. The peeling method has been recently found to be effective for acne treatment. This study aimed to compare the efficacy of pyruvic acid 50% and salicylic acid 30% peeling in the treatment of mild to moderate acne. Materials and Methods: In a prospective single-blinded clinical trial, 86 patients with acne were randomly assigned into two groups. In both groups, the routine treatment of acne (topical solution of erythromycin 4%, triclorocarban soap, and sunscreen were used twice a day for 8 weeks. In addition, salicylic acid 30% for the control group and pyruvic acid 50% for the case group were used. In both groups, acne severity index (ASI was calculated before and at week 2, 4, 6, and 8 of the treatment. Patient satisfaction was assessed at the end of the treatment. Side effects were recorded using a checklist. Results: In both groups, the reduction in the number of comedones, papules, and ASI were statistically significant (P < 0.001 in the course of treatment. However, it was not significant regarding the number of pustules (P = 0.09. None of the number of comedone, papules, pustules, and ASI was statistically different between study groups. Both treatment groups had similar side effects except for scaling in the fifth session, which was significantly lower in salicylic acid - treated patients (P = 0.015. Conclusion: Both pyruvic acid 50% and salicylic acid 30% are effective in the improvement of mild to moderate acne with no significant difference in efficacy and side effects.

  18. Comparison the effectiveness of pyruvic acid 50% and salicylic acid 30% in the treatment of acne.

    Science.gov (United States)

    Jaffary, Fariba; Faghihi, Gita; Saraeian, Sara; Hosseini, Sayed Mohsen

    2016-01-01

    Acne vulgaris is a chronic inflammatory disease of the pilosebaceous follicles and one of the most common skin diseases. The peeling method has been recently found to be effective for acne treatment. This study aimed to compare the efficacy of pyruvic acid 50% and salicylic acid 30% peeling in the treatment of mild to moderate acne. In a prospective single-blinded clinical trial, 86 patients with acne were randomly assigned into two groups. In both groups, the routine treatment of acne (topical solution of erythromycin 4%, triclorocarban soap, and sunscreen) were used twice a day for 8 weeks. In addition, salicylic acid 30% for the control group and pyruvic acid 50% for the case group were used. In both groups, acne severity index (ASI) was calculated before and at week 2, 4, 6, and 8 of the treatment. Patient satisfaction was assessed at the end of the treatment. Side effects were recorded using a checklist. In both groups, the reduction in the number of comedones, papules, and ASI were statistically significant ( P < 0.001) in the course of treatment. However, it was not significant regarding the number of pustules ( P = 0.09). None of the number of comedone, papules, pustules, and ASI was statistically different between study groups. Both treatment groups had similar side effects except for scaling in the fifth session, which was significantly lower in salicylic acid - treated patients ( P = 0.015). Both pyruvic acid 50% and salicylic acid 30% are effective in the improvement of mild to moderate acne with no significant difference in efficacy and side effects.

  19. Maturation of pig oocytes in vitro in a medium with pyruvate

    Directory of Open Access Journals (Sweden)

    H. Gonzales-Figueroa

    2005-06-01

    Full Text Available The aim of in vitro maturation oocyte systems is to produce oocytes of comparable quality to those derived in vivo. The present study was designed to examine the surface morphological changes of the cumulus-oocyte complex (COC and nuclear maturation in a culture system containing pyruvate. Ovaries were obtained from a slaughterhouseand transported to the laboratory within 2 h at 35-39ºC,and rinsed three times in 0.9% NaCl. The COCs were harvested from the ovaries and in vitro maturation was evaluated in San Marcos (SM medium, a chemically defined culture system containing 22.3 mM sodium pyruvate. Oocytes were cultured in SM, SM + porcine follicular fluid (pFF and in SM + pFF + gonadotropins (eCG and hCG for 20-22 h and then without hormonal supplements for an additional 20-22 h. After culture, the degree of cumulus expansion and frequency of nuclear maturation were determined. Oocytes matured in SM (40.9% and SM + pFF (42.9% showed moderate cumulus expansion, whereas oocytes matured in SM + pFF + gonadotropins (54.6% showed high cumulus expansion. The maturation rate of cultured oocytes, measured in function of the presence of the polar corpuscle, did not differ significantly between SM (40.9 ± 3.6% and SM + pFF (42.9 ± 3.7%. These results indicate that pig oocytes can be successfully matured in a chemically definedmedium and suggest a possible bifunctional role of pyruvate as an energy substrate and as an antioxidant protecting oocytes against the stress of the in vitro environment.

  20. Protective Effect of Pyruvate Against Radiation-Induced Damage in Collagenized Tissues

    Science.gov (United States)

    Griko, Y. V.; Yan, Xiaoli

    2016-01-01

    Exposure to high doses of ionizing radiation produces both acute and late effects on the collagenized tissues and have profound effects on wound healing. Because of the crucial practical importance for new radioprotective agents, our study has been focused on evaluation of the efficacy of non-toxic naturally occurring compounds to protect tissue integrity against high-dose gamma radiation. Here, we demonstrate that molecular integrity of collagen may serve as a sensitive biological marker for quantitative evaluation of molecular damage to collagenized tissue and efficacy of radioprotective agents. Increasing doses of gamma radiation (0-50kGy) result in progressive destruction of the native collagen fibrils, which provide a structural framework, strength, and proper milieu for the regenerating tissue. The strategy used in this study involved the thermodynamic specification of all structural changes in collagenized matrix of skin, aortic heart valve, and bone tissue induced by different doses and conditions of g-irradiation. This study describes a simple biophysical approach utilizing the Differential Scanning Calorimetry (DSC) to characterize the structural resistance of the aortic valve matrix exposed to different doses of g-irradiation. It allows us to identify the specific response of each constituent as well as to determine the influence of the different treatments on the characteristic parameters of protein structure. We found that pyruvate, a substance that naturally occurs in the body, provide significant protection (up to 80%) from biochemical and biomechanical damage to the collagenized tissue through the effective targeting of reactive oxygen species. The recently discovered role of pyruvate in the cell antioxidant defense to O2 oxidation, and its essential constituency in the daily human diet, indicate that the administration of pyruvate-based radioprotective formulations may provide safe and effective protection from deleterious effects of ionizing

  1. A comparison of quantitative methods for clinical imaging with hyperpolarized (13)C-pyruvate.

    Science.gov (United States)

    Daniels, Charlie J; McLean, Mary A; Schulte, Rolf F; Robb, Fraser J; Gill, Andrew B; McGlashan, Nicholas; Graves, Martin J; Schwaiger, Markus; Lomas, David J; Brindle, Kevin M; Gallagher, Ferdia A

    2016-04-01

    Dissolution dynamic nuclear polarization (DNP) enables the metabolism of hyperpolarized (13)C-labelled molecules, such as the conversion of [1-(13)C]pyruvate to [1-(13)C]lactate, to be dynamically and non-invasively imaged in tissue. Imaging of this exchange reaction in animal models has been shown to detect early treatment response and correlate with tumour grade. The first human DNP study has recently been completed, and, for widespread clinical translation, simple and reliable methods are necessary to accurately probe the reaction in patients. However, there is currently no consensus on the most appropriate method to quantify this exchange reaction. In this study, an in vitro system was used to compare several kinetic models, as well as simple model-free methods. Experiments were performed using a clinical hyperpolarizer, a human 3 T MR system, and spectroscopic imaging sequences. The quantitative methods were compared in vivo by using subcutaneous breast tumours in rats to examine the effect of pyruvate inflow. The two-way kinetic model was the most accurate method for characterizing the exchange reaction in vitro, and the incorporation of a Heaviside step inflow profile was best able to describe the in vivo data. The lactate time-to-peak and the lactate-to-pyruvate area under the curve ratio were simple model-free approaches that accurately represented the full reaction, with the time-to-peak method performing indistinguishably from the best kinetic model. Finally, extracting data from a single pixel was a robust and reliable surrogate of the whole region of interest. This work has identified appropriate quantitative methods for future work in the analysis of human hyperpolarized (13)C data. © 2016 The Authors. NMR in Biomedicine published by John Wiley & Sons Ltd.

  2. Domain interaction in rabbit muscle pyruvate kinase. II. Small angle neutron scattering and computer simulation.

    Science.gov (United States)

    Consler, T G; Uberbacher, E C; Bunick, G J; Liebman, M N; Lee, J C

    1988-02-25

    The effects of ligands on the structure of rabbit muscle pyruvate kinase were studied by small angle neutron scattering. The radius of gyration, RG, decreases by about 1 A in the presence of the substrate phosphoenolpyruvate, but increases by about the same magnitude in the presence of the allosteric inhibitor phenylalanine. With increasing pH or in the absence of Mg2+ and K+, the RG of pyruvate kinase increases. Hence, there is a 2-A difference in RG between two alternative conformations. Length distribution analysis indicates that, under all experimental conditions which increase the radius of gyration, there is a pronounced increase observed in the probability for interatomic distance between 80 and 110 A. These small angle neutron scattering results indicate a "contraction" and "expansion" of the enzyme when it transforms between its active and inactive forms. Using the alpha-carbon coordinates of crystalline cat muscle pyruvate kinase, a length distribution profile was calculated, and it matches the scattering profile of the inactive form. These observations are expected since the crystals were grown in the absence of divalent cations (Stuart, D. I., Levine, M., Muirhead, H., and Stammers, D. K. (1979) J. Mol. Biol. 134, 109-142). Hence, results from neutron scattering, x-ray crystallographic, and sedimentation studies (Oberfelder, R. W., Lee, L. L.-Y., and Lee, J.C. (1984) Biochemistry 23, 3813-3821) are totally consistent with each other. With the aid of computer modeling, the crystal structure has been manipulated in order to effect changes that are consistent with the conformational change described by the solution scattering data. The structural manipulation involves the rotation of the B domain relative to the A domain, leading to the closure of the cleft between these domains. These manipulations resulted in the generation of new sets of atomic (C-alpha) coordinates, which were utilized in calculations, the result of which compared favorably with the

  3. Creatine and creatine pyruvate reduce hypoxia-induced effects on phrenic nerve activity in the juvenile mouse respiratory system.

    Science.gov (United States)

    Scheer, Monika; Bischoff, Anna M; Kruzliak, Peter; Opatrilova, Radka; Bovell, Douglas; Büsselberg, Dietrich

    2016-08-01

    Adequate concentrations of ATP are required to preserve physiological cell functions and protect tissue from hypoxic damage. Decreased oxygen concentration results in ATP synthesis relying increasingly on the presence of phosphocreatine. The lack of ATP through hypoxic insult to neurons that generate or regulate respiratory function, would lead to the cessation of breathing (apnea). It is not clear whether creatine plays a role in maintaining respiratory phrenic nerve (PN) activity during hypoxic challenge. The aim of the study was to test the effects of exogenously applied creatine or creatine pyruvate in maintaining PN induced respiratory rhythm against the deleterious effects of severe hypoxic insult using Working Heart-Brainstem (WHB) preparations of juvenile Swiss type mice. WHB's were perfused with control perfusate or perfusate containing either creatine [100μM] or creatine pyruvate [100μM] prior to hypoxic challenge and PN activity recorded throughout. Results showed that severe hypoxic challenge resulted in an initial transient increase in PN activity, followed by a reduction in that activity leading to respiratory apnea. The results demonstrated that perfusing the WHB preparation with creatine or creatine pyruvate, significantly reduced the onset of apnea compared to control conditions, with creatine pyruvate being the more effective substance. Overall, creatine and creatine pyruvate each produced time-dependent degrees of protection against severe hypoxic-induced disturbances of PN activity. The underlying protective mechanisms are unknown and need further investigations. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Neuron-astrocyte interactions, pyruvate carboxylation and the pentose phosphate pathway in the neonatal rat brain

    OpenAIRE

    Morken, Tora Sund; Brekke, Eva Mari Førland; Håberg, Asta; Widerøe, Marius; Brubakk, Ann-Mari; Sonnewald, Ursula

    2014-01-01

    Glucose and acetate metabolism and the synthesis of amino acid neurotransmitters, anaplerosis, glutamate-glutamine cycling and the pentose phosphate pathway (PPP) have been extensively investigated in the adult, but not the neonatal rat brain. To do this, 7 day postnatal (P7) rats were injected with [1-(13)C]glucose and [1,2-(13)C]acetate and sacrificed 5, 10, 15, 30 and 45 min later. Adult rats were injected and sacrificed after 15 min. To analyse pyruvate carboxylation and PPP activity duri...

  5. Inborn Errors of Metabolism with Acidosis: Organic Acidemias and Defects of Pyruvate and Ketone Body Metabolism.

    Science.gov (United States)

    Schillaci, Lori-Anne P; DeBrosse, Suzanne D; McCandless, Shawn E

    2018-04-01

    When a child presents with high-anion gap metabolic acidosis, the pediatrician can proceed with confidence by recalling some basic principles. Defects of organic acid, pyruvate, and ketone body metabolism that present with acute acidosis are reviewed. Flowcharts for identifying the underlying cause and initiating life-saving therapy are provided. By evaluating electrolytes, blood sugar, lactate, ammonia, and urine ketones, the provider can determine the likelihood of an inborn error of metabolism. Freezing serum, plasma, and urine samples during the acute presentation for definitive diagnostic testing at the provider's convenience aids in the differential diagnosis. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Effect of Rhizobium and Mycorhiza inoculation on the nursery growth of Acacia and Teline monspessulana; Efecto de la aplicacion de biofertilizantes en Acacia decurrens y Teline monspessulana en vivero

    Energy Technology Data Exchange (ETDEWEB)

    Layton, G; Lozano de Yunda, A; Chaparro, H

    1999-12-01

    In an experiment accomplished in the tree nursery Tisquesusa located in Madrid (Cundinamarca) was evaluated the effect of the inoculation with strains selected of foreign and Indigenous rhizobium and Arbuscular mycorrhizal fungi am (Glomus folescutolum) on the growth, nitrogen fixation, and micorrization of Acacia (Acacia decurrens) and Retamo (Teline monspessulana) that they are used In soils recovery by the Corporacion Autonoma Regional de Cundinamarca CAR. The studied species presented positive response to the inoculation with rhizobium; the indigenous strain DQ6-09, isolated in Guatavita (Cundinamarca), presented the better results in Retamo and also in Acacia alone and in mixture with the foreign strain T1881. The inoculation with fungi AM increased the heights, dry weights, phosphorus content and percentage of micorrization in Acacia and Retamo. The double inoculation with fungi ma and rhizobium it did not increase the nitrogen fixing of Acacia while in Retamo was presented a positive effect with the strain DQ6-09.

  7. Forestación de un terreno decapitado con Robinia pseudoacacia inoculada con Rhizobium spp. y Glomus deserticola Afforestation of a desurfaced field with Robinia pseudoacacia inoculated with Rhizobium spp. and Glomus deserticola

    Directory of Open Access Journals (Sweden)

    Alejandro E Ferrari

    2010-07-01

    Full Text Available Los terrenos decapitados constituyen un caso extremo de degradación de suelos aptos para agricultura, con graves consecuencias ambientales. El propósito de este trabajo fue ensayar los efectos de la inoculación de acacia blanca (Robinia pseudoacacia L. con una cepa efectiva de Rhizobium y un hongo de micorrizas arbusculares (Glomus deserticola en la supervivencia y crecimiento temprano de plantas trasplantadas a un terreno decapitado de Balcarce, comparando con fresno como árbol no fijador de nitrógeno. La supervivencia inicial fue muy buena (mayor del 77%, especialmente para los fresnos y las acacias inoculadas, las cuales mostraron significativamente mayor supervivencia al estrés por sequía que las acacias control. Todas las plantas se mostraron igualmente tolerantes al ataque de liebres y al estrés por heladas tardías. Durante el primer año las acacias inoculadas crecieron más rápido que las no inoculadas. En el segundo año las alturas se equipararon en parte, probablemente por la colonización de las acacias control con rizobios o micorrizas naturales del suelo. De todos modos, las acacias inoculadas siempre mostraron valores mayores de los distintos parámetros de desarrollo (altura total, diámetro de la copa y cantidad de ramificaciones que las plantas control, tanto en los sectores poco decapitados como en los más severamente degradados. En conclusión, la doble inoculación previa de acacia blanca mejoró la supervivencia inicial, aumentó tolerancia a la sequía y el crecimiento en 2 años y medio desde la plantación. Esta práctica de manejo sería entonces muy recomendable para reducir el período de vivero en la producción de árboles, así como lograr ejemplares más resistentes y mejor adaptados para proyectos de recuperación de suelos degradados.Many agricultural lands in Buenos Aires Province (Argentina have traditionally been desurfaced for the manufacture of bricks and other building materials. The desurfaced

  8. Degradación de Fenantreno por bacterias del género Burkholderia y Rhizobium aisladas de nódulos de mimosas

    Directory of Open Access Journals (Sweden)

    Arnoldo Wong-Villarreal

    2017-01-01

    Full Text Available El presente trabajo tuvo como objetivo identificar y evaluar la capacidad de degradación de microorganismos aislados de nódulos de mimosas, que puedan ser utilizados en procesos de biorremediación de suelos contaminados con fenantreno . Método . Se realizó el aislamiento de 122 cepas bacterianas de nódulos de mimosas; fueron crecidas en el medio de cultivo Maconkey para descartar enterobacterias. L as cepas bacterianas que dieron resultado negativo a esta prueba, fueron inoculadas en el medio de cultivo que contenía como úni ca fuente de carbono fenantreno; tres aislados tuvieron la capacidad de crecer en este medio. Las tres cepas fueron identificadas por secuencia del gen 1 6s ribosomal, se evaluó su capacidad de crecimiento en presencia de fenantreno mediante curvas de crecimiento microbiano; la capacidad para degradar fenantreno de las tres cepas fue cuantificada por cromatografía de gases acoplado a masas. Resultados . La s secuencias obtenidas del gen 16s ribosomal tienen relación genética con las especies de Burkholderia phenoliruptrix , Burkholderia phymatum y Rhizobium paknamense. El crecimiento microbiano de las tres cepas, suministradas con fenantreno, tuvieron un comp ortamiento similar al control , el cual contenía succinato como fuente de carbono. La cepa de Burkholderia sp. BB26 degradó 78.5 % , Burkholderia sp. BB24 68.5 % y Rhizobium sp. BY8 99%. Discusión . Los resultados de degradación de fenantreno por las cepas de Burkholderia sp. BB26 , Burkholderia sp. BB24 y Rhizobium sp. BY8 sugieren que las tres cepas tienen p otencial para utilizarse en procesos de biorremediación de suelos contaminados con fenantreno.

  9. Effect of gamma radiation on the concentration of pyruvate and lactate in erythrocytes of healthy men after submaximal physical exercise

    International Nuclear Information System (INIS)

    Zagorski, T.; Dudek, I.; Berkan, L.; Chmielewski, H.; Kedziora, J.

    1993-01-01

    The aim of this work was to study the effect of gamma radiation and submaximal physical exercise on the concentration of final products of anaerobic glycolytic pathway in erythrocytes of healthy men. Twenty one men aged 20-22 were examined. They underwent physical exercise at doses of 2 w/kg body weight for 15 min. Erythrocytes were taken in the rest and after physical exercise and were exposed to gamma radiation (500 Gy doses) from 60 Co source. The concentration of pyruvate was estimated by Fermognost tests and the concentration of lactate by Boehringer Mannheim tests. The submaximal physical exercise was found to cause a significantly increased concentration of pyruvate and lactate in the non-radiated and irradiated erythrocytes. Gamma radiation at 500 Gy dose was found to increase concentration of pyruvate in erythrocytes (in the rest and after physical exercise) with simultaneous decrease of lactate concentration. (author). 17 refs, 1 tab

  10. Recovery of Pyruvic Acid using Tri-n-butylamine Dissolved in Non-Toxic Diluent (Rice Bran Oil)

    Science.gov (United States)

    Pal, Dharm; Keshav, Amit

    2016-04-01

    An attempt has been made to investigate the effectiveness of the vegetable oil based biocompatible solvent for the separation of pyruvic acid from fermentation broth, by using rice bran oil as natural, non-toxic diluent. Reactive extraction of pyruvic acid (0.1-0.5 k mol/m3) from aqueous solutions has been studied using tri-n-butylamine (TBA; 10-70 %) as an extractant dissolved in non toxic rice bran oil at T = 30 ± 1 °C. Results were presented in terms of distribution coefficient (Kd), extraction efficiency (E %), loading ratio (Z), and complexation constant (\\varphi_{α β }). Extraction equilibrium was interpreted using mass action modeling approach. Based on the extent of loading (Z < 0.5) only (1:1), pyruvic acid: TBA complex was proposed. Equilibrium complexation constant was evaluated to 1.22 m3/k mol. Results obtained are useful in understanding the extraction mechanism.

  11. Analysis of Poly-β-Hydroxybutyrate in Rhizobium japonicum Bacteroids by Ion-Exclusion High-Pressure Liquid Chromatography and UV Detection †

    Science.gov (United States)

    Karr, Dale B.; Waters, James K.; Emerich, David W.

    1983-01-01

    Ion-exclusion high-pressure liquid chromatography (HPLC) was used to measure poly-β-hydroxybutyrate (PHB) in Rhizobium japonicum bacteroids. The products in the acid digest of PHB-containing material were fractionated by HPLC on Aminex HPX-87H ion-exclusion resin for organic acid analysis. Crotonic acid formed from PHB during acid digestion was detected by its intense absorbance at 210 nm. The Aminex-HPLC method provides a rapid and simple chromatographic technique for routine analysis of organic acids. Results of PHB analysis by Aminex-HPLC were confirmed by gas chromatography and spectrophotometric analysis. PMID:16346443

  12. Biotreatment of paper mill effluent using alkaliphilic Rhizobium sp. NCIM 5590 isolated from meteoric alkaline Lonar Lake, Buldhana District, Maharashtra, India

    DEFF Research Database (Denmark)

    Raut, Avinash A.; Phugare, Swapnil S.; Kalyani, Dayanand C.

    2018-01-01

    Bacterial strain Rhizobium sp. was isolated from littoral soil of meteoric alkaline Lonar Lake and used to treat paper mill waste water. The bacterium was found to fix 125.7 nmol of C2H4 formed ml−1 culture media in 72 hr by ARA (acetylene reduction assay). The optimum pH for its growth was 12, w...... was studied using Allium cepa root cells, evaluating various biochemical parameters to assess the toxicity, including lipid peroxidation, protein oxidation, antioxidant enzyme status (catalase, superoxide dismutase) and genotoxicity assays using single cell gel electrophoresis (SCGE)....

  13. Pyruvate oxidase influences the sugar utilization pattern and capsule production in Streptococcus pneumoniae.

    Directory of Open Access Journals (Sweden)

    Sandra M Carvalho

    Full Text Available Pyruvate oxidase is a key function in the metabolism and lifestyle of many lactic acid bacteria and its activity depends on the presence of environmental oxygen. In Streptococcus pneumoniae the protein has been suggested to play a major role in metabolism and has been implicated in virulence, oxidative stress survival and death in stationary phase. Under semi-aerobic conditions, transcriptomic and metabolite profiling analysis of a spxB mutant grown on glucose showed minor changes compared to the wild type, apart from the significant induction of two operons involved in carbohydrate uptake and processing. This induction leads to a change in the sugar utilization capabilities of the bacterium, as indicated by the analysis of the growth profiles of the D39 parent and spxB mutant on alternative carbohydrates. Metabolic analysis and growth experiments showed that inactivation of SpxB has no effect on the glucose fermentation pattern, except under aerobic conditions. More importantly, we show that mutation of spxB results in the production of increased amounts of capsule, the major virulence factor of S. pneumoniae. Part of this increase can be attributed to induction of capsule operon (cps transcription. Therefore, we propose that S. pneumoniae utilizes pyruvate oxidase as an indirect sensor of the oxygenation of the environment, resulting in the adaption of its nutritional capability and the amount of capsule to survive in the host.

  14. Characterization of cDNAs encoding human pyruvate dehydrogenase α subunit

    International Nuclear Information System (INIS)

    Ho, Lap; Wexler, I.D.; Liu, Techung; Thekkumkara, T.J.; Patel, M.S.

    1989-01-01

    A cDNA clone (1,423 base pairs) comprising the entire coding region of the precursor form of the α subunit of pyruvate dehydrogenase (E 1 α) has been isolated from a human liver cDNA library in phage λgt11. The first 29 amino acids deduced from the open reading frame correspond to a typical mitochondrial targeting leader sequence. The remaining 361 amino acids, starting at the N terminus with phenylalanine, represent the mature mitochondrial E 1 α peptide. The cDNA has 43 base pairs in the 5' untranslated region and 210 base pairs in the 3' untranslated region, including a polyadenylylation signal and a short poly(A) tract. The nucleotide sequence of human liver E 1 α cDNA was confirmed by the nucleotide sequences of three overlapping fragments generated from human liver and fibroblast RNA by reverse transcription and DNA amplification by the polymerase chain reaction. This consensus nucleotide sequence of human liver E 1 α cDNA resolves existing discrepancies among three previously reported human E 1 α cDNAs and provides the unambiguous reference sequence needed for the characterization of genetic mutations in pyruvate dehydrogenase-deficient patients

  15. Pyruvate decarboxylase provides growing pollen tubes with a competitive advantage in petunia.

    Science.gov (United States)

    Gass, Nathalie; Glagotskaia, Tatiana; Mellema, Stefan; Stuurman, Jeroen; Barone, Mario; Mandel, Therese; Roessner-Tunali, Ute; Kuhlemeier, Cris

    2005-08-01

    Rapid pollen tube growth places unique demands on energy production and biosynthetic capacity. The aim of this work is to understand how primary metabolism meets the demands of such rapid growth. Aerobically grown pollen produce ethanol in large quantities. The ethanolic fermentation pathway consists of two committed enzymes: pyruvate decarboxylase (PDC) and alcohol dehydrogenase (ADH). Because adh mutations do not affect male gametophyte function, the obvious question is why pollen synthesize an abundant enzyme if they could do just as well without. Using transposon tagging in Petunia hybrida, we isolated a null mutant in pollen-specific Pdc2. Growth of the mutant pollen tubes through the style is reduced, and the mutant allele shows reduced transmission through the male, when in competition with wild-type pollen. We propose that not ADH but rather PDC is the critical enzyme in a novel, pollen-specific pathway. This pathway serves to bypass pyruvate dehydrogenase enzymes and thereby maintain biosynthetic capacity and energy production under the unique conditions prevailing during pollen-pistil interaction.

  16. Modulation of Malaria Phenotypes by Pyruvate Kinase (PKLR Variants in a Thai Population.

    Directory of Open Access Journals (Sweden)

    Rebekah van Bruggen

    Full Text Available Pyruvate kinase (PKLR is a critical erythrocyte enzyme that is required for glycolysis and production of ATP. We have shown that Pklr deficiency in mice reduces the severity (reduced parasitemia, increased survival of blood stage malaria induced by infection with Plasmodium chabaudi AS. Likewise, studies in human erythrocytes infected ex vivo with P. falciparum show that presence of host PK-deficiency alleles reduces infection phenotypes. We have characterized the genetic diversity of the PKLR gene, including haplotype structure and presence of rare coding variants in two populations from malaria endemic areas of Thailand and Senegal. We investigated the effect of PKLR genotypes on rich longitudinal datasets including haematological and malaria-associated phenotypes. A coding and possibly damaging variant (R41Q was identified in the Thai population with a minor allele frequency of ~4.7%. Arginine 41 (R41 is highly conserved in the pyruvate kinase family and its substitution to Glutamine (R41Q affects protein stability. Heterozygosity for R41Q is shown to be associated with a significant reduction in the number of attacks with Plasmodium falciparum, while correlating with an increased number of Plasmodium vivax infections. These results strongly suggest that PKLR protein variants may affect the frequency, and the intensity of malaria episodes induced by different Plasmodium parasites in humans living in areas of endemic malaria.

  17. Heavy-atom isotope effects on binding of reactants to lactate dehydrogenase and pyruvate kinase

    International Nuclear Information System (INIS)

    Gawlita, E.

    1993-04-01

    18 O and 13 C kinetic isotope effects have been measured on the reaction of pyruvate kinase with phospho-enol-pyruvate and ADP using a remote label technique. The magnitude of both investigated isotope effects showed a dependence on the concentration of ADP. However, while the carbon effect was simply 'washed out' to unity at high ATP concentration, the oxygen effect becomes inverse and reached 0.9928 at the highest used concentration of ADP. Such a result testifies that the assumption of the negligible effect of isotopic substitution on enzyme-substrate associations remains correct only for carbon effects. An equilibrium 18 O isotope effect on association of oxalate with lactate dehydrogenase in the presence of NADHP has been evaluated by both experimental and theoretical means. Experimental methods, which involved equilibrium dialysis and gas chromatographic/mass spectrometric measurement of isotopic ration, yielded an inverse value of 0.9840. Semiempirical methods involved vibrational analysis of oxalate in two different environments. The comparison of calculated values with the experimentally determined isotope effect indicated that the AM 1 Hamiltonian proved superior to its PM 3 counterpart in this modelling. 160 refs, 8 figs, 18 tabs

  18. n-Octyl gallate as inhibitor of pyruvate carboxylation and lactate gluconeogenesis.

    Science.gov (United States)

    Eler, Gabrielle Jacklin; Santos, Israel Souza; de Moraes, Amarilis Giaretta; Comar, Jurandir Fernando; Peralta, Rosane Marina; Bracht, Adelar

    2015-04-01

    The alkyl gallates are found in several natural and industrial products. In the latter products, these compounds are added mainly for preventing oxidation. In the present work, the potencies of methyl gallate, n-propyl gallate, n-pentyl gallate, and n-octyl gallate as inhibitors of pyruvate carboxylation and lactate gluconeogenesis were evaluated. Experiments were done with isolated mitochondria and the isolated perfused rat liver. The potency of the gallic acid esters as inhibitors of pyruvate carboxylation in isolated mitochondria obeyed the following decreasing sequence: n-octyl gallate > n-pentyl gallate > n-propyl gallate > methyl gallate. A similar sequence of decreasing potency for lactate gluconeogenesis inhibition in the perfused liver was found in terms of the portal venous concentration. Both actions correlate with the lipophilicity of the compounds. The effects are harmful at high concentrations. At appropriate concentrations, however, octyl gallate should act therapeutically because its inhibitory action on gluconeogenesis will contribute further to its proposed antihyperglycemic effects. © 2014 Wiley Periodicals, Inc.

  19. Gluconeogenesis in Leishmania mexicana: contribution of glycerol kinase, phosphoenolpyruvate carboxykinase, and pyruvate phosphate dikinase.

    Science.gov (United States)

    Rodriguez-Contreras, Dayana; Hamilton, Nicklas

    2014-11-21

    Gluconeogenesis is an active pathway in Leishmania amastigotes and is essential for their survival within the mammalian cells. However, our knowledge about this pathway in trypanosomatids is very limited. We investigated the role of glycerol kinase (GK), phosphoenolpyruvate carboxykinase (PEPCK), and pyruvate phosphate dikinase (PPDK) in gluconeogenesis by generating the respective Leishmania mexicana Δgk, Δpepck, and Δppdk null mutants. Our results demonstrated that indeed GK, PEPCK, and PPDK are key players in the gluconeogenesis pathway in Leishmania, although stage-specific differences in their contribution to this pathway were found. GK participates in the entry of glycerol in promastigotes and amastigotes; PEPCK participates in the entry of aspartate in promastigotes, and PPDK is involved in the entry of alanine in amastigotes. Furthermore, the majority of alanine enters into the pathway via decarboxylation of pyruvate in promastigotes, whereas pathway redundancy is suggested for the entry of aspartate in amastigotes. Interestingly, we also found that l-lactate, an abundant glucogenic precursor in mammals, was used by Leishmania amastigotes to synthesize mannogen, entering the pathway through PPDK. On the basis of these new results, we propose a revision in the current model of gluconeogenesis in Leishmania, emphasizing the differences between amastigotes and promastigotes. This work underlines the importance of studying the trypanosomatid intracellular life cycle stages to gain a better understanding of the pathologies caused in humans. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  20. Pyruvate carboxylase is required for glutamine-independent growth of tumor cells

    Science.gov (United States)

    Cheng, Tzuling; Sudderth, Jessica; Yang, Chendong; Mullen, Andrew R.; Jin, Eunsook S.; Matés, José M.; DeBerardinis, Ralph J.

    2011-01-01

    Tumor cells require a constant supply of macromolecular precursors, and interrupting this supply has been proposed as a therapeutic strategy in cancer. Precursors for lipids, nucleic acids, and proteins are generated in the tricarboxylic acid (TCA) cycle and removed from the mitochondria to participate in biosynthetic reactions. Refilling the pool of precursor molecules (anaplerosis) is therefore crucial to maintain cell growth. Many tumor cells use glutamine to feed anaplerosis. Here we studied how “glutamine-addicted” cells react to interruptions of glutamine metabolism. Silencing of glutaminase (GLS), which catalyzes the first step in glutamine-dependent anaplerosis, suppressed but did not eliminate the growth of glioblastoma cells in culture and in vivo. Profiling metabolic fluxes in GLS-suppressed cells revealed induction of a compensatory anaplerotic mechanism catalyzed by pyruvate carboxylase (PC), allowing the cells to use glucose-derived pyruvate rather than glutamine for anaplerosis. Although PC was dispensable when glutamine was available, forcing cells to adapt to low-glutamine conditions rendered them absolutely dependent on PC for growth. Furthermore, in other cell lines, measuring PC activity in nutrient-replete conditions predicted dependence on specific anaplerotic enzymes. Cells with high PC activity were resistant to GLS silencing and did not require glutamine for survival or growth, but displayed suppressed growth when PC was silenced. Thus, PC-mediated, glucose-dependent anaplerosis allows cells to achieve glutamine independence. Induction of PC during chronic suppression of glutamine metabolism may prove to be a mechanism of resistance to therapies targeting glutaminolysis. PMID:21555572

  1. Methylobacterium sp. isolated from a Finnish paper machine produces highly pyruvated galactan exopolysaccharide.

    Science.gov (United States)

    Verhoef, René; de Waard, Pieter; Schols, Henk A; Siika-aho, Matti; Voragen, Alphons G J

    2003-09-01

    The slime-forming bacterium Methylobacterium sp. was isolated from a Finnish paper machine and its exopolysaccharide (EPS) was produced on laboratory scale. Sugar compositional analysis revealed a 100% galactan (EPS). However, FT-IR showed a very strong peak at 1611 cm(-1) showing the presence of pyruvate. Analysis of the pyruvate content revealed that, based on the sugar composition, the EPS consists of a trisaccharide repeating unit consisting of D-galactopyranose and [4,6-O-(1-carboxyethylidene)]-D-galactopyranose with a molar ratio of 1:2, respectively. Both linkage analysis and 2D homo- and heteronuclear 1H and 13C NMR spectroscopy revealed the following repeating unit: -->3)-[4,6-O-(1-carboxyethylidene)]-alpha-D-Galp-(1-->3)[4,6-O-(1-carboxyethylidene)]-alpha-D-Galp-(1-->3)-alpha-D-Galp-(1-->. By enrichment cultures from various ground and compost heap samples a polysaccharide-degrading culture was obtained that produced an endo acting enzyme able to degrade the EPS described. The enzyme hydrolysed the EPS to a large extent, releasing oligomers that mainly consisted out of two repeating units.

  2. Pyruvate oxidase influences the sugar utilization pattern and capsule production in Streptococcus pneumoniae.

    Science.gov (United States)

    Carvalho, Sandra M; Farshchi Andisi, Vahid; Gradstedt, Henrik; Neef, Jolanda; Kuipers, Oscar P; Neves, Ana R; Bijlsma, Jetta J E

    2013-01-01

    Pyruvate oxidase is a key function in the metabolism and lifestyle of many lactic acid bacteria and its activity depends on the presence of environmental oxygen. In Streptococcus pneumoniae the protein has been suggested to play a major role in metabolism and has been implicated in virulence, oxidative stress survival and death in stationary phase. Under semi-aerobic conditions, transcriptomic and metabolite profiling analysis of a spxB mutant grown on glucose showed minor changes compared to the wild type, apart from the significant induction of two operons involved in carbohydrate uptake and processing. This induction leads to a change in the sugar utilization capabilities of the bacterium, as indicated by the analysis of the growth profiles of the D39 parent and spxB mutant on alternative carbohydrates. Metabolic analysis and growth experiments showed that inactivation of SpxB has no effect on the glucose fermentation pattern, except under aerobic conditions. More importantly, we show that mutation of spxB results in the production of increased amounts of capsule, the major virulence factor of S. pneumoniae. Part of this increase can be attributed to induction of capsule operon (cps) transcription. Therefore, we propose that S. pneumoniae utilizes pyruvate oxidase as an indirect sensor of the oxygenation of the environment, resulting in the adaption of its nutritional capability and the amount of capsule to survive in the host.

  3. Ketogenic diet in pyruvate dehydrogenase complex deficiency: short- and long-term outcomes.

    Science.gov (United States)

    Sofou, Kalliopi; Dahlin, Maria; Hallböök, Tove; Lindefeldt, Marie; Viggedal, Gerd; Darin, Niklas

    2017-03-01

    Our aime was to study the short- and long-term effects of ketogenic diet on the disease course and disease-related outcomes in patients with pyruvate dehydrogenase complex deficiency, the metabolic factors implicated in treatment outcomes, and potential safety and compliance issues. Pediatric patients diagnosed with pyruvate dehydrogenase complex deficiency in Sweden and treated with ketogenic diet were evaluated. Study assessments at specific time points included developmental and neurocognitive testing, patient log books, and investigator and parental questionnaires. A systematic literature review was also performed. Nineteen patients were assessed, the majority having prenatal disease onset. Patients were treated with ketogenic diet for a median of 2.9 years. All patients alive at the time of data registration at a median age of 6 years. The treatment had a positive effect mainly in the areas of epilepsy, ataxia, sleep disturbance, speech/language development, social functioning, and frequency of hospitalizations. It was also safe-except in one patient who discontinued because of acute pancreatitis. The median plasma concentration of ketone bodies (3-hydroxybutyric acid) was 3.3 mmol/l. Poor dietary compliance was associated with relapsing ataxia and stagnation of motor and neurocognitive development. Results of neurocognitive testing are reported for 12 of 19 patients. Ketogenic diet was an effective and safe treatment for the majority of patients. Treatment effect was mainly determined by disease phenotype and attainment and maintenance of ketosis.

  4. Differential regulation of mitochondrial pyruvate carrier genes modulates respiratory capacity and stress tolerance in yeast.

    Directory of Open Access Journals (Sweden)

    Alba Timón-Gómez

    Full Text Available Mpc proteins are highly conserved from yeast to humans and are necessary for the uptake of pyruvate at the inner mitochondrial membrane, which is used for leucine and valine biosynthesis and as a fuel for respiration. Our analysis of the yeast MPC gene family suggests that amino acid biosynthesis, respiration rate and oxidative stress tolerance are regulated by changes in the Mpc protein composition of the mitochondria. Mpc2 and Mpc3 are highly similar but functionally different: Mpc2 is most abundant under fermentative non stress conditions and important for amino acid biosynthesis, while Mpc3 is the most abundant family member upon salt stress or when high respiration rates are required. Accordingly, expression of the MPC3 gene is highly activated upon NaCl stress or during the transition from fermentation to respiration, both types of regulation depend on the Hog1 MAP kinase. Overexpression experiments show that gain of Mpc2 function leads to a severe respiration defect and ROS accumulation, while Mpc3 stimulates respiration and enhances tolerance to oxidative stress. Our results identify the regulated mitochondrial pyruvate uptake as an important determinant of respiration rate and stress resistance.

  5. Differential regulation of mitochondrial pyruvate carrier genes modulates respiratory capacity and stress tolerance in yeast.

    Science.gov (United States)

    Timón-Gómez, Alba; Proft, Markus; Pascual-Ahuir, Amparo

    2013-01-01

    Mpc proteins are highly conserved from yeast to humans and are necessary for the uptake of pyruvate at the inner mitochondrial membrane, which is used for leucine and valine biosynthesis and as a fuel for respiration. Our analysis of the yeast MPC gene family suggests that amino acid biosynthesis, respiration rate and oxidative stress tolerance are regulated by changes in the Mpc protein composition of the mitochondria. Mpc2 and Mpc3 are highly similar but functionally different: Mpc2 is most abundant under fermentative non stress conditions and important for amino acid biosynthesis, while Mpc3 is the most abundant family member upon salt stress or when high respiration rates are required. Accordingly, expression of the MPC3 gene is highly activated upon NaCl stress or during the transition from fermentation to respiration, both types of regulation depend on the Hog1 MAP kinase. Overexpression experiments show that gain of Mpc2 function leads to a severe respiration defect and ROS accumulation, while Mpc3 stimulates respiration and enhances tolerance to oxidative stress. Our results identify the regulated mitochondrial pyruvate uptake as an important determinant of respiration rate and stress resistance.

  6. Rhizobium leguminosarum bv. trifolii rosR is required for interaction with clover, biofilm formation and adaptation to the environment

    Directory of Open Access Journals (Sweden)

    Piersiak Tomasz

    2010-11-01

    Full Text Available Abstract Background Rhizobium leguminosarum bv. trifolii is a symbiotic nitrogen-fixing bacterium that elicits nodules on roots of host plants Trifolium spp. Bacterial surface polysaccharides are crucial for establishment of a successful symbiosis with legumes that form indeterminate-type nodules, such as Trifolium, Pisum, Vicia, and Medicago spp. and aid the bacterium in withstanding osmotic and other environmental stresses. Recently, the R. leguminosarum bv. trifolii RosR regulatory protein which controls exopolysaccharide production has been identified and characterized. Results In this work, we extend our earlier studies to the characterization of rosR mutants which exhibit pleiotropic phenotypes. The mutants produce three times less exopolysaccharide than the wild type, and the low-molecular-weight fraction in that polymer is greatly reduced. Mutation in rosR also results in quantitative alterations in the polysaccharide constituent of lipopolysaccharide. The rosR mutants are more sensitive to surface-active detergents, antibiotics of the beta-lactam group and some osmolytes, indicating changes in the bacterial membranes. In addition, the rosR mutants exhibit significant decrease in motility and form a biofilm on plastic surfaces, which differs significantly in depth, architecture, and bacterial viability from that of the wild type. The most striking effect of rosR mutation is the considerably decreased attachment and colonization of root hairs, indicating that the mutation affects the first stage of the invasion process. Infection threads initiate at a drastically reduced rate and frequently abort before they reach the base of root hairs. Although these mutants form nodules on clover, they are unable to fix nitrogen and are outcompeted by the wild type in mixed inoculations, demonstrating that functional rosR is important for competitive nodulation. Conclusions This report demonstrates the significant role RosR regulatory protein plays in

  7. Interacción de Tsukamurella paurometabola C-924 con Rhizobium leguminosarum biovar phaseoli CFH en el cultivo de frijol

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    Marieta Marín Bruzos

    2013-01-01

    Full Text Available En el estudio se evaluaron, mediante análisis de los parámetros fenológicos de las plantas, la interacción de Tsukamurella paurometabola C-924 con Rhizobium leguminosarum biovar phaseoli CFH en el cultivo de frijol. Se emplearon cuatro tratamientos: plantas sin inocular (control, inoculadas con T. paurometabola C-924, inoculadas con R. leguminosarum biovar phaseoli CFH e inoculadas con ambas cepas. Se observaron diferencias significativas (P < 0.01 en los porcentajes de germinación de las plantas tratadas con microorganismos de forma independiente o conjunta con respecto al control sin inocular. Se determinó que la inoculación de T. paurometabola C-924 afectó el proceso de nodulación de R. leguminosarum biovar phaseoli CFH. Sin embargo, esto no incidió de manera significativa en la altura de las plantas ni en el diámetro del tallo, ya que no se encontraron diferencias entre los tratamientos para estos parámetros. Para el número de hojas, los mejores resultados se obtuvieron con la aplicación de T. paurometabola C-924. Se concluyó que la interacción de T. paurometabola C-924 con R. leguminosarum biovar phaseoli CFH en el frijol estimuló significativamente la germinación de las semillas y el número de hojas de las plantas con respecto al control sin inocular. Aunque la aplicación de T. paurometabola C-924 no favoreció la nodulación de R. leguminosarum biovar phaseoli CFH, esto no afectó las características fenológicas del cultivo.

  8. Identification and Characterization of RibN, a Novel Family of Riboflavin Transporters from Rhizobium leguminosarum and Other Proteobacteria

    Science.gov (United States)

    García Angulo, Víctor A.; Bonomi, Hernán R.; Posadas, Diana M.; Serer, María I.; Torres, Alfredo G.; Zorreguieta, Ángeles

    2013-01-01

    Rhizobia are symbiotic bacteria able to invade and colonize the roots of legume plants, inducing the formation of nodules, where bacteria reduce atmospheric nitrogen (N2) to ammonia (NH3). Riboflavin availability influences the capacity of rhizobia to survive in the rhizosphere and to colonize roots. In this study, we identified the RL1692 gene of Rhizobium leguminosarum downstream of a flavin mononucleotide (FMN) riboswitch. RL1692 encodes a putative transmembrane permease with two EamA domains. The presence of an FMN riboswitch regulating a transmembrane protein is usually observed in riboflavin transporters, suggesting that RL1692 may be involved in riboflavin uptake. The product of RL1692, which we named RibN, is conserved in members of the alpha-, beta-, and gammaproteobacteria and shares no significant identity with any riboflavin transporter previously identified. In this work, we show that RibN is localized in the membrane cellular fraction and its expression is downregulated by riboflavin. By heterologous expression in a Brucella abortus mutant auxotrophic for riboflavin, we demonstrate that RibN possesses flavin transport activity. Similarly, we also demonstrate that RibN orthologues from Ochrobactrum anthropi and Vibrio cholerae (which lacks the FMN riboswitch) are able to transport riboflavin. An R. leguminosarum ribN null mutant exhibited lower nodule occupancy levels in pea plants during symbiosis assays. Thus, we propose that RibN and its homologues belong to a novel family of riboflavin transporters. This work provides the first experimental description of riboflavin transporters in Gram-negative bacteria. PMID:23935051

  9. Mutation of praR in Rhizobium leguminosarum enhances root biofilms, improving nodulation competitiveness by increased expression of attachment proteins.

    Science.gov (United States)

    Frederix, Marijke; Edwards, Anne; Swiderska, Anna; Stanger, Andrew; Karunakaran, Ramakrishnan; Williams, Alan; Abbruscato, Pamela; Sanchez-Contreras, Maria; Poole, Philip S; Downie, J Allan

    2014-08-01

    In Rhizobium leguminosarum bv. viciae, quorum-sensing is regulated by CinR, which induces the cinIS operon. CinI synthesizes an AHL, whereas CinS inactivates PraR, a repressor. Mutation of praR enhanced biofilms in vitro. We developed a light (lux)-dependent assay of rhizobial attachment to roots and demonstrated that mutation of praR increased biofilms on pea roots. The praR mutant out-competed wild-type for infection of pea nodules in mixed inoculations. Analysis of gene expression by microarrays and promoter fusions revealed that PraR represses its own transcription and mutation of praR increased expression of several genes including those encoding secreted proteins (the adhesins RapA2, RapB and RapC, two cadherins and the glycanase PlyB), the polysaccharide regulator RosR, and another protein similar to PraR. PraR bound to the promoters of several of these genes indicating direct repression. Mutations in rapA2, rapB, rapC, plyB, the cadherins or rosR did not affect the enhanced root attachment or nodule competitiveness of the praR mutant. However combinations of mutations in rapA, rapB and rapC abolished the enhanced attachment and nodule competitiveness. We conclude that relief of PraR-mediated repression determines a lifestyle switch allowing the expression of genes that are important for biofilm formation on roots and the subsequent initiation of infection of legume roots. © 2014 The Authors. Molecular Microbiology published by John Wiley & Sons Ltd.

  10. Growth of cowpea plants inoculated with Rhizobium in a saline-sodic soil after application of gypsum

    Directory of Open Access Journals (Sweden)

    Angela Jessyka Pereira Brito Fontenele

    Full Text Available Two experiments were carried out with the aim of evaluating the growth of cowpea cultivated in saline-sodic soils corrected with gypsum: one experiment in the laboratory, to identify the best level of gypsum for the correction of the saline-sodic soils of the state of Pernambuco, Brazil; and the other in a greenhouse, after correction of the soils. As the test plant, the cowpea cultivar pele de moça, inoculated with Rhizobium strain BR3267 was used. The experiments were arranged in a randomised block design in a 2 x 5 factorial arrangement, two soils and five levels of the gypsum requirement (GR, equivalent to 50, 100, 150, 200 and 250% of the GR of the soil, as determined by the Schoonover M-1 method, with five replications. The following were evaluated: electrical conductivity of the soil saturation extract (EC, soil exchangeable sodium and percentage of soil exchangeable sodium (ESP, number of nodules (NN, nodule dry weight (NDW, shoot dry weight (SDW, shoot height (PH and nitrogen concentration (N in the shoots. Application of 100% of the GR, followed by the enough water for leaching, was effective for the correction of soil sodicity. The application of increasing levels of soil GR resulted in an increase in the number of nodules, dry weight of the nodules and shoots, and the height and levels of N absorbed by the plants in soil S2. In soil S1, the use of levels of 200 and 250% of soil the GR caused a decrease in all the variables under study.

  11. Functional relationships between plasmids and their significance for metabolism and symbiotic performance of Rhizobium leguminosarum bv. trifolii.

    Science.gov (United States)

    Stasiak, Grażyna; Mazur, Andrzej; Wielbo, Jerzy; Marczak, Małgorzata; Zebracki, Kamil; Koper, Piotr; Skorupska, Anna

    2014-11-01

    Rhizobium leguminosarum bv. trifolii TA1 (RtTA1) is a soil bacterium establishing a highly specific symbiotic relationship with clover, which is based on the exchange of molecular signals between the host plant and the microsymbiont. The RtTA1 genome is large and multipartite, composed of a chromosome and four plasmids, which comprise approximately 65 % and 35 % of the total genome, respectively. Extrachromosomal replicons were previously shown to confer significant metabolic versatility to bacteria, which is important for their adaptation in the soil and nodulation competitiveness. To investigate the contribution of individual RtTA1 plasmids to the overall cell phenotype, metabolic properties and symbiotic performance, a transposon-based elimination strategy was employed. RtTA1 derivatives cured of pRleTA1b or pRleTA1d and deleted in pRleTA1a were obtained. In contrast to the in silico predictions of pRleTA1b and pRleTA1d, which were described as chromid-like replicons, both appeared to be completely curable. On the other hand, for pRleTA1a (symbiotic plasmid) and pRleTA1c, which were proposed to be unessential for RtTA1 viability, it was not possible to eliminate them at all (pRleTA1c) or entirely (pRleTA1a). Analyses of the phenotypic traits of the RtTA1 derivatives obtained revealed the functional significance of individual plasmids and their indispensability for growth, certain metabolic pathways, production of surface polysaccharides, autoaggregation, biofilm formation, motility and symbiotic performance. Moreover, the results allow us to suggest broad functional cooperation among the plasmids in shaping the phenotypic properties and symbiotic capabilities of rhizobia.

  12. Yabani Baklagil Bitkilerinden, Mikrobiyal Gübre Olarak Kullanılan Rhizobium Spp. Bakterilerinin İzolasyonu

    Directory of Open Access Journals (Sweden)

    Hatice Öğütcü

    2014-05-01

    Full Text Available Araştırmamızda kullanılan yabani baklagil bitkileri ( Medicago sativa, M.lupulina ve M. varia Erzurum iline ait yüksek rakımlı (2000-2500m bölgelerden (Palandöken dağı, Alibaba dağı, Turnagöl dağı, Hasanbaba dağı, Eğerli dağı, Yıldırım dağı, Çubuklu dağı, Deveboynu mevkii, Kayakyolu mevkii, Telsizler tepesi ve Dumlu tepesi Haziran ve Temmuz aylarında toplandı. Bu bitkilerden elde edilen nodüller steril edilerek YMA (Yeast Mannitol Agar plaklarına çizgi ekim yapıldı ve petriler 28+1ºC’de 3-5 gün süreyle inkübasyona bırakıldı. İnkübasyon süresi sonunda oluşan tipik koloniler oluşturan (beyaz, saydam veya hafif mat, mukozlu, yuvarlak, kabarık 39 izolat seçilerek yatık YMA tüplerine aktarıldı ve buzdolabında +4ºC’de muhafaza edildi. Sonraki aşamada bu izolatlar sitolojik ve biyokimyasal analizlerle tanımlanmaya çalışıldı. Bu amaçla izolatlar; Brom Thymol Mavili ve Kongo Kırmızılı YMA’da üreme, gram özelliği, hareket, katalaz ve oksidaz testlerine tabi tutularak değerlendirildi. Yapılan sitolojik ve biyokimyasal analizler sonucunda elde edilen 39 izolatın 28’inin Rhizobium spp. olduğu tespit edildi.

  13. Differences between magnesium-activated and manganese-activated pyruvate kinase from the muscle of Concholepas concholepas.

    Science.gov (United States)

    González, R; Carvajal, N; Morán, A

    1984-01-01

    In contrast to the Mg2+-activated enzyme, in the presence of Mn2+ pyruvate kinase exhibits hyperbolic kinetics with respect to the substrate phosphoenolpyruvate and is insensitive to fructose 1,6-biphosphate, phenylalanine and alanine. However, with both metal activated species inhibition by excess ADP is observed. In contrast with Mg2+, which affords significant protection against inactivation caused by 5,5'-dithiobis (2-nitrobenzoic acid), the rate of inactivation by this reagent is increased in the presence of Mn2+. Differences in conformational changes induced by combination of pyruvate kinase with Mg2+ or Mn2+ were indicated by u.v. difference spectra.

  14. Preparation of C-II labeled pyruvic acid for use in assessment of hypoxia in tumors. Project 4

    International Nuclear Information System (INIS)

    Anon.

    1986-01-01

    Of the three methods of synthesis of C-II-labeled pyruvic acid that we had proposed to investigate in order to determine the best and most appropriate synthesis of C-II-labeled pyruvate, the cold chemistry of Method A, via an isocyanide intermediate, has been verified. Similarly, the cold chemistry of Method B, via the 1,3-dithiane derivative, has been verified up to the deprotection and last step of the synthesis. The difficulties which have been encountered with the biochemistry of Method C from ribulose 1,5-diphosphate, have yet to be resolved. 12 refs., 6 figs

  15. Enhancing the [13C]bicarbonate signal in cardiac hyperpolarized [1‐13C]pyruvate MRS studies by infusion of glucose, insulin and potassium

    DEFF Research Database (Denmark)

    Lauritzen, Mette Hauge; Laustsen, Christoffer; Butt, Sadia Asghar

    2013-01-01

    A change in myocardial metabolism is a known effect of several diseases. MRS with hyperpolarized 13C‐labelled pyruvate is a technique capable of detecting changes in myocardial pyruvate metabolism, and has proven to be useful for the evaluation of myocardial ischaemia in vivo. However, during fas...

  16. Ethyl pyruvate inhibits proliferation and induces apoptosis of hepatocellular carcinoma via regulation of the HMGB1–RAGE and AKT pathways

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Ping; Dai, Weiqi; Wang, Fan; Lu, Jie; Shen, Miao; Chen, Kan; Li, Jingjing; Zhang, Yan; Wang, Chengfen; Yang, Jing; Zhu, Rong; Zhang, Huawei; Zheng, Yuanyuan; Guo, Chuan-Yong, E-mail: guochuanyong@hotmail.com; Xu, Ling, E-mail: xuling606@sina.com

    2014-01-24

    Highlights: • Ethyl pyruvate inhibits liver cancer. • Promotes apoptosis. • Decreased the expression of HMGB1, p-Akt. - Abstract: Ethyl pyruvate (EP) was recently identified as a stable lipophilic derivative of pyruvic acid with significant antineoplastic activities. The high mobility group box-B1 (HMGB1)–receptor for advanced glycation end-products (RAGE) and the protein kinase B (Akt) pathways play a crucial role in tumorigenesis and development of many malignant tumors. We tried to observe the effects of ethyl pyruvate on liver cancer growth and explored its effects in hepatocellular carcinoma model. In this study, three hepatocellular carcinoma cell lines were treated with ethyl pyruvate. An MTT colorimetric assay was used to assess the effects of EP on cell proliferation. Flow cytometry and TUNEL assays were used to analyze apoptosis. Real-time PCR, Western blotting and immunofluorescence demonstrated ethyl pyruvate reduced the HMGB1–RAGE and AKT pathways. The results of hepatoma orthotopic tumor model verified the antitumor effects of ethyl pyruvate in vivo. EP could induce apoptosis and slow the growth of liver cancer. Moreover, EP decreased the expression of HMGB1, RAGE, p-AKT and matrix metallopeptidase-9 (MMP9) and increased the Bax/Bcl-2 ratio. In conclusion, this study demonstrates that ethyl pyruvate induces apoptosis and cell-cycle arrest in G phase in hepatocellular carcinoma cells, plays a critical role in the treatment of cancer.

  17. Persistent changes in the initial rate of pyruvate transport by isolated rat liver mitochondria after preincubation with adenine nucleotides and calcium ions

    NARCIS (Netherlands)

    Vaartjes, W.J.; Breejen, J.N. den; Geelen, M.J.H.; Bergh, S.G. van den

    1980-01-01

    1. Preincubation of isolated rat-liver mitochondria in the presence of adenine nucleotides or Ca2+ results in definite and persistent changes in the initial rate of pyruvate transport. 2. These changes in the rate of pyruvate transport are accompanied by equally persistent changes in the opposite

  18. A novel mechanism for the pyruvate protection against zinc-induced cytotoxicity: mediation by the chelating effect of citrate and isocitrate.

    Science.gov (United States)

    Sul, Jee-Won; Kim, Tae-Youn; Yoo, Hyun Ju; Kim, Jean; Suh, Young-Ah; Hwang, Jung Jin; Koh, Jae-Young

    2016-08-01

    Intracellular accumulation of free zinc contributes to neuronal death in brain injuries such as ischemia and epilepsy. Pyruvate, a glucose metabolite, has been shown to block zinc neurotoxicity. However, it is largely unknown how pyruvate shows such a selective and remarkable protective effect. In this study, we sought to find a plausible mechanism of pyruvate protection against zinc toxicity. Pyruvate almost completely blocked cortical neuronal death induced by zinc, yet showed no protective effects against death induced by calcium (ionomycin, NMDA) or ferrous iron. Of the TCA cycle intermediates, citrate, isocitrate, and to a lesser extent oxaloacetate, protected against zinc toxicity. We then noted with LC-MS/MS assay that exposure to pyruvate, and to a lesser degree oxaloacetate, increased levels of citrate and isocitrate, which are known zinc chelators. While pyruvate added only during zinc exposure did not reduce zinc toxicity, citrate and isocitrate added only during zinc exposure, as did extracellular zinc chelator CaEDTA, completely blocked it. Furthermore, addition of pyruvate after zinc exposure substantially reduced intracellular zinc levels. Our results suggest that the remarkable protective effect of pyruvate against zinc cytotoxicity may be mediated indirectly by the accumulation of intracellular citrate and isocitrate, which act as intracellular zinc chelators.

  19. Pyruvate induces transient tumor hypoxia by enhancing mitochondrial oxygen consumption and potentiates the anti-tumor effect of a hypoxia-activated prodrug TH-302.

    Directory of Open Access Journals (Sweden)

    Yoichi Takakusagi

    Full Text Available BACKGROUND: TH-302 is a hypoxia-activated prodrug (HAP of bromo isophosphoramide mustard that is selectively activated within hypoxic regions in solid tumors. Our recent study showed that intravenously administered bolus pyruvate can transiently induce hypoxia in tumors. We investigated the mechanism underlying the induction of transient hypoxia and the combination use of pyruvate to potentiate the anti-tumor effect of TH-302. METHODOLOGY/RESULTS: The hypoxia-dependent cytotoxicity of TH-302 was evaluated by a viability assay in murine SCCVII and human HT29 cells. Modulation in cellular oxygen consumption and in vivo tumor oxygenation by the pyruvate treatment was monitored by extracellular flux analysis and electron paramagnetic resonance (EPR oxygen imaging, respectively. The enhancement of the anti-tumor effect of TH-302 by pyruvate treatment was evaluated by monitoring the growth suppression of the tumor xenografts inoculated subcutaneously in mice. TH-302 preferentially inhibited the growth of both SCCVII and HT29 cells under hypoxic conditions (0.1% O2, with minimal effect under aerobic conditions (21% O2. Basal oxygen consumption rates increased after the pyruvate treatment in SCCVII cells in a concentration-dependent manner, suggesting that pyruvate enhances the mitochondrial respiration to consume excess cellular oxygen. In vivo EPR oxygen imaging showed that the intravenous administration of pyruvate globally induced the transient hypoxia 30 min after the injection in SCCVII and HT29 tumors at the size of 500-1500 mm(3. Pretreatment of SCCVII tumor bearing mice with pyruvate 30 min prior to TH-302 administration, initiated with small tumors (∼ 550 mm(3, significantly delayed tumor growth. CONCLUSIONS/SIGNIFICANCE: Our in vitro and in vivo studies showed that pyruvate induces transient hypoxia by enhancing mitochondrial oxygen consumption in tumor cells. TH-302 therapy can be potentiated by pyruvate pretreatment if started at the

  20. Pyruvate induces transient tumor hypoxia by enhancing mitochondrial oxygen consumption and potentiates the anti-tumor effect of a hypoxia-activated prodrug TH-302.

    Science.gov (United States)

    Takakusagi, Yoichi; Matsumoto, Shingo; Saito, Keita; Matsuo, Masayuki; Kishimoto, Shun; Wojtkowiak, Jonathan W; DeGraff, William; Kesarwala, Aparna H; Choudhuri, Rajani; Devasahayam, Nallathamby; Subramanian, Sankaran; Munasinghe, Jeeva P; Gillies, Robert J; Mitchell, James B; Hart, Charles P; Krishna, Murali C

    2014-01-01

    TH-302 is a hypoxia-activated prodrug (HAP) of bromo isophosphoramide mustard that is selectively activated within hypoxic regions in solid tumors. Our recent study showed that intravenously administered bolus pyruvate can transiently induce hypoxia in tumors. We investigated the mechanism underlying the induction of transient hypoxia and the combination use of pyruvate to potentiate the anti-tumor effect of TH-302. The hypoxia-dependent cytotoxicity of TH-302 was evaluated by a viability assay in murine SCCVII and human HT29 cells. Modulation in cellular oxygen consumption and in vivo tumor oxygenation by the pyruvate treatment was monitored by extracellular flux analysis and electron paramagnetic resonance (EPR) oxygen imaging, respectively. The enhancement of the anti-tumor effect of TH-302 by pyruvate treatment was evaluated by monitoring the growth suppression of the tumor xenografts inoculated subcutaneously in mice. TH-302 preferentially inhibited the growth of both SCCVII and HT29 cells under hypoxic conditions (0.1% O2), with minimal effect under aerobic conditions (21% O2). Basal oxygen consumption rates increased after the pyruvate treatment in SCCVII cells in a concentration-dependent manner, suggesting that pyruvate enhances the mitochondrial respiration to consume excess cellular oxygen. In vivo EPR oxygen imaging showed that the intravenous administration of pyruvate globally induced the transient hypoxia 30 min after the injection in SCCVII and HT29 tumors at the size of 500-1500 mm(3). Pretreatment of SCCVII tumor bearing mice with pyruvate 30 min prior to TH-302 administration, initiated with small tumors (∼ 550 mm(3)), significantly delayed tumor growth. Our in vitro and in vivo studies showed that pyruvate induces transient hypoxia by enhancing mitochondrial oxygen consumption in tumor cells. TH-302 therapy can be potentiated by pyruvate pretreatment if started at the appropriate tumor size and oxygen concentration.

  1. The Lipopolysaccharide Lipid A Long-Chain Fatty Acid Is Important for Rhizobium leguminosarum Growth and Stress Adaptation in Free-Living and Nodule Environments.

    Science.gov (United States)

    Bourassa, Dianna V; Kannenberg, Elmar L; Sherrier, D Janine; Buhr, R Jeffrey; Carlson, Russell W

    2017-02-01

    Rhizobium bacteria live in soil and plant environments, are capable of inducing symbiotic nodules on legumes, invade these nodules, and develop into bacteroids that fix atmospheric nitrogen into ammonia. Rhizobial lipopolysaccharide (LPS) is anchored in the bacterial outer membrane through a specialized lipid A containing a very long-chain fatty acid (VLCFA). VLCFA function for rhizobial growth in soil and plant environments is not well understood. Two genes, acpXL and lpxXL, encoding acyl carrier protein and acyltransferase, are among the six genes required for biosynthesis and transfer of VLCFA to lipid A. Rhizobium leguminosarum mutant strains acpXL, acpXL - /lpxXL - , and lpxXL - were examined for LPS structure, viability, and symbiosis. Mutations in acpXL and lpxXL abolished VLCFA attachment to lipid A. The acpXL mutant transferred a shorter acyl chain instead of VLCFA. Strains without lpxXL neither added VLCFA nor a shorter acyl chain. In all strains isolated from nodule bacteria, lipid A had longer acyl chains compared with laboratory-cultured bacteria, whereas mutant strains displayed altered membrane properties, modified cationic peptide sensitivity, and diminished levels of cyclic β-glucans. In pea nodules, mutant bacteroids were atypically formed and nitrogen fixation and senescence were affected. The role of VLCFA for rhizobial environmental fitness is discussed.

  2. VsENOD5, VsENOD12 and VsENOD40 expression during Rhizobium-induced nodule formation on Vicia sativa roots

    DEFF Research Database (Denmark)

    Vijn, I; Yang, W C; Pallisgård, N

    1995-01-01

    We isolated ENOD5, ENOD12 and ENOD40 homologues from Vicia sativa and studied their expression pattern during Rhizobium-induced nodule formation. Comparison of the VsENOD40 nucleotide sequence with the pea, soybean and alfalfa ENOD40 sequences showed that the sequences contain two conserved regions...... the expression pattern of VsENOD5, VsENOD12 and VsENOD40 during Rhizobium-induced nodule formation. Although the expression of these genes is largely similar to that of the pea counterparts, differences where found for the expression of VsENOD12 and VsENOD40 in Vicia. VsENOD12 is expressed in the whole...... prefixation zone II, whereas in pea ENOD12 is only expressed in the distal part of this zone. VsENOD40 is expressed in the uninfected cells of interzone II-III, while in pea ENOD40 is expressed in both the uninfected and infected cells of this zone. Udgivelsesdato: 1995-Sep...

  3. BOOKLET TO INSTITUTO PEDAGOGICO NACIONAL TEACHERS ABOUT SYMBIOSIS AND PROCESSES ON BIOTECHNOLOGY: THE BIOFERTILIZER Rhizobium sp IN Phaseolus vulgaris WITH ALTERNATIVE TO SYMBIOSIS FOR Phaseolus vulgaris

    Directory of Open Access Journals (Sweden)

    María Camila Quevedo Rubiano

    2016-09-01

    Full Text Available This article presents the results of the thesis carried out in the research group of Biotechnology Teaching in Colombia, with the aim of providing teachers of Biology of Instituto Pedagogico Nacional a booklet that can strengthen the teaching of biotechnology processes using Rhizobium sp reduction of chemical fertilizers and symbiosis with Phaseolus vulgaris.   The booklet contains a proposal of practical activities that enable teachers of this institution to use spaces like the farm, enabling to teach biotechnology related to agronomy. Therefore, for this project was considered two Biological and Pedagogical approaches, the first is within the analytical empirical paradigm in the process of microbiological characterization of Rhizobium and their Biofertilizing ability in beans; and the teaching approach within the design of a booklet that includes the findings of this study as a contribution to the reduction of chemical fertilizers school farm. In order to have a complete analysis of the work it was subjected to quantitative and qualitative methods.   This biotech practice is included in the booklet showing in bioassays that bacteria has biofertilizer without inhibiting potential symbiosis, and that research and teaching biological concepts from scientific expertise can be promoted in Biology class for students to understand its context in a significant way, to be used in different levels of education; also it is a teaching strategy.

  4. Effect of aldicarb on growth and radio-carbon (/sup 14/C) and radio-phosphorus (/sup 32/P) assimilation by Rhizobium japonicum

    Energy Technology Data Exchange (ETDEWEB)

    Balasubramanian, A; Nilakantan, G [University of Agricultural Sciences, Bangalore (India). Radiotracer Lab.

    1976-01-01

    In vitro studies on the effect of aldicarb (2-methyl-2-(methyl thio) propionaldehde-o-methyl carbamoyl oxime), a soil applied systemic insecticide, on Rhizobium japonicum revealed that the chemical (at 1,2 and 5 ppm levels) stimulated the growth of the organism initially upto 48 hr which declined thereafter upto 72 hr. The incorporation of /sup 14/C-glucose by the cells considerably reduced due to the insecticide treatment. The production of extracellular, water-soluble slime (polysacchardes) was also reduced considerably with increased concentrations of the chemical. However, the incorporation of /sup 14/C-radio-activity in the extracellular slime generally enhanced due to the treatment, upto 6 hr after injection of the radioactivity, which declined significantly later at 15 hr, indicating a qualitative difference in the extracellular polysaccharides produced by the insecticide treated cells. The insecticide treatment drastically reduced the incorporation of /sup 32/P-disodium hydrogen phosphate into Rhizobium cells, but enhanced the specific activity of the extracellular polysacchrides.

  5. Effect in field of the native strain COL6 of Rhizobium leguminosarum bv. viciae on common bean cv. Percal in Ecuador

    Directory of Open Access Journals (Sweden)

    Klever Iván Granda-Mora

    2017-07-01

    Full Text Available Inoculation with selected Rhizobium strains of common bean (Phaseolus vulgaris L. contributes to the agricultural yield of this legume, improves soil fertility and reduces the use of nitrogen fertilizers in sustainable agricultural systems. The research aimed to determine the effect in field of the native strain Rhizobium leguminosarum bv. viciae COL6 on growth, N fixation and agricultural yield in common bean cv. Percal. A field trial was carried out to evaluate the parameters of nodulation, biomass, nitrogen fixation, yield components and agricultural yield in common bean. In addition, soil analyzes were performed before and after experimentation. Prior to planting an inoculant was formulated with the strain COL6. The seeds of cv. Percal were mixed in 250 g inoculant per 10 kg of seed and it was sown manually in the soil. The results of growth, N fixation (total N % and agricultural yield demonstrated the positive effect of inoculation with the bacterial inoculant comparable with chemical fertilizers. The increase in agricultural yield with bacterial inoculant application and chemical fertilization with respect to control was 62 and 64 %, respectively. The results of the soil analysis were variable with respect to the initial physical-chemical characteristics. The promising results of bacterial inoculant use and the effective stimulation in common bean, open the doors for its potential use in Ecuadorian soils and with that the desired potential yield can be reached.

  6. Selected Chemical Properties of Soybean Rhizosphere Soil as Influenced by Cropping Systems, Rhizobium Inoculation, and the Supply of Phosphorus and Potassium after Two Consecutive Cropping Seasons

    Directory of Open Access Journals (Sweden)

    Daniel Nyoki

    2018-01-01

    Full Text Available The field experiment was carried out in northern Tanzania to assess the effects of intercropping systems, Rhizobium inoculation, and fertilization with P and K on chemical properties of soybean rhizosphere soil. The experiment was laid out in split-split plot design with 2 × 4 × 7 factorial arrangement replicated thrice. The main plots had two inoculation treatments and the subplots were comprised of four cropping systems which were sole maize, sole soybean, and two intercropping at different soybean spacing (75 × 20 and 75 × 40 cm. The fertilizer levels (kg/ha control (0 kg/ha; 20 K; 40 K; 26 P; 52 P; 26 P + 20 K; and 52 P + 40 K were assigned to sub-subplots. Statistical analysis was performed using ANOVA. Least Significant Difference was used to compare treatment means at p=0.05 significance level. The results indicated that rhizosphere soil chemical properties such as pH, organic carbon (OC, and macro- and micronutrients (N, P, Ca, Mg, and Na and Fe, Cu, Mn, and Zn, resp. were significantly increased in the Rhizobium inoculated soybean over the control. The supply of P and K fertilizers significantly increased the rhizosphere content of macronutrients (P, K, Ca, and Mg and also they altered the pH and EC of the rhizosphere soil relative to control.

  7. Strigolactones in the Rhizobium-legume symbiosis: Stimulatory effect on bacterial surface motility and down-regulation of their levels in nodulated plants.

    Science.gov (United States)

    Peláez-Vico, María A; Bernabéu-Roda, Lydia; Kohlen, Wouter; Soto, María J; López-Ráez, Juan A

    2016-04-01

    Strigolactones (SLs) are multifunctional molecules acting as modulators of plant responses under nutrient deficient conditions. One of the roles of SLs is to promote beneficial association with arbuscular mycorrhizal (AM) fungi belowground under such stress conditions, mainly phosphorus shortage. Recently, a role of SLs in the Rhizobium-legume symbiosis has been also described. While SLs' function in AM symbiosis is well established, their role in the Rhizobium-legume interaction is still emerging. Recently, SLs have been suggested to stimulate surface motility of rhizobia, opening the possibility that they could also act as molecular cues. The possible effect of SLs in the motility in the alfalfa symbiont Sinorhizobium meliloti was investigated, showing that the synthetic SL analogue GR24 stimulates swarming motility in S. meliloti in a dose-dependent manner. On the other hand, it is known that SL production is regulated by nutrient deficient conditions and by AM symbiosis. Using the model alfalfa-S. meliloti, the impact of phosphorus and nitrogen deficiency, as well as of nodulation on SL production was also assessed. The results showed that phosphorus starvation promoted SL biosynthesis, which was abolished by nitrogen deficiency. In addition, a negative effect of nodulation on SL levels was detected, suggesting a conserved mechanism of SL regulation upon symbiosis establishment. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  8. Effect of aldicarb on growth and radio-carbon (14C) and radio-phosphorus (32P) assimilation by Rhizobium japonicum

    International Nuclear Information System (INIS)

    Balasubramanian, A.; Nilakantan, Gita

    1976-01-01

    In vitro studies on the effect of aldicarb (2-methyl-2-(methyl thio) propionaldehde-o-methyl carbamoyl oxime), a soil applied systemic insecticide, on Rhizobium japonicum revealed that the chemical (at 1,2 and 5 ppm levels) stimulated the growth of the organism initially upto 48 hr which declined thereafter upto 72 hr. The incorporation of 14 C-glucose by the cells considerably reduced due to the insecticide treatment. The production of extracellular, water-soluble slime (polysacchardes) was also reduced considerably with increased concentrations of the chemical. However, the incorporation of 14 C-radio-activity in the extracellular slime generally enhanced due to the treatment, upto 6 hr after injection of the radioactivity, which declined significantly later at 15 hr, indicating a qualitative difference in the extracellular polysaccharides produced by the insecticide treated cells. The insecticide treatment drastically reduced the incorporation of 32 P-disodium hydrogen phosphate into Rhizobium cells, but enhanced the specific activity of the extracellular polysacchrides. (author)

  9. Simultaneous hyperpolarized 13C-pyruvate MRI and 18F-FDG-PET in cancer (hyperPET)

    DEFF Research Database (Denmark)

    Gutte, Henrik; Hansen, Adam E.; Henriksen, Sarah T.

    2015-01-01

    named this concept hyper PET. Intravenous injection of the hyperpolarized 13C-pyruvate results in an increase of 13C-lactate, 13C-alanine and 13CCO2 (13C-HCO3) resonance peaks relative to the tissue, disease and the metabolic state probed. Accordingly, with dynamic nuclear polarization (DNP) and use......In this paper we demonstrate, for the first time, the feasibility of a new imaging concept - combined hyperpolarized 13C-pyruvate magnetic resonance spectroscopic imaging (MRSI) and 18F-FDG-PET imaging. This procedure was performed in a clinical PET/MRI scanner with a canine cancer patient. We have...... of 13C-pyruvate it is now possible to directly study the Warburg Effect through the rate of conversion of 13C-pyruvate to 13C-lactate. In this study, we combined it with 18F-FDG-PET that studies uptake of glucose in the cells. A canine cancer patient with a histology verified local recurrence...

  10. “Scanning mutagenesis” of the amino acid sequences flanking phosphorylation site 1 of the mitochondrial pyruvate dehydrogenase complex

    Science.gov (United States)

    The mitochondrial pyruvate dehydrogenase complex is regulated by reversible seryl-phosphorylation of the E1alpha subunit by a dedicated, intrinsic kinase. The phospho-complex is reactivated when dephosphorylated by an intrinsic PP2C-type protein phosphatase. Both the position of the phosphorylated...

  11. An internal deletion in MTH1 enables growth on glucose of pyruvate-decarboxylase negative, non-fermentative Saccharomyces cerevisiae

    NARCIS (Netherlands)

    Oud, B.; Flores, C.L.; Gancedo, C.; Zhang, X.; Trueheart, J.; Daran, J.M.; Pronk, J.T.; Van Maris, A.J.A.

    2012-01-01

    Background Pyruvate-decarboxylase negative (Pdc-) strains of Saccharomyces cerevisiae combine the robustness and high glycolytic capacity of this yeast with the absence of alcoholic fermentation. This makes Pdc-S. cerevisiae an interesting platform for efficient conversion of glucose towards

  12. Leigh syndrome associated with a deficiency of the pyruvate dehydrogenase complex: results of treatment with a ketogenic diet

    NARCIS (Netherlands)

    Wijburg, F. A.; Barth, P. G.; Bindoff, L. A.; Birch-Machin, M. A.; van der Blij, J. F.; Ruitenbeek, W.; TURNBULL, D. M.; Schutgens, R. B.

    1992-01-01

    A one-year-old boy suffering from intermittent lactic acidosis, muscular hypotonia, horizontal gaze paralysis and spasticity in both legs had low activity of the pyruvate dehydrogenase complex associated with low amounts of immunoreactive E 1 alpha and E 1 beta. Leigh syndrome was diagnosed on the

  13. Detection and formation scenario of citric acid, pyruvic acid, and other possible metabolism precursors in carbonaceous meteorites

    Science.gov (United States)

    Cooper, George; Reed, Chris; Nguyen, Dang; Carter, Malika; Wang, Yi

    2011-01-01

    Carbonaceous meteorites deliver a variety of organic compounds to Earth that may have played a role in the origin and/or evolution of biochemical pathways. Some apparently ancient and critical metabolic processes require several compounds, some of which are relatively labile such as keto acids. Therefore, a prebiotic setting for any such individual process would have required either a continuous distant source for the entire suite of intact precursor molecules and/or an energetic and compact local synthesis, particularly of the more fragile members. To date, compounds such as pyruvic acid, oxaloacetic acid, citric acid, isocitric acid, and α-ketoglutaric acid (all members of the citric acid cycle) have not been identified in extraterrestrial sources or, as a group, as part of a “one pot” suite of compounds synthesized under plausibly prebiotic conditions. We have identified these compounds and others in carbonaceous meteorites and/or as low temperature (laboratory) reaction products of pyruvic acid. In meteorites, we observe many as part of three newly reported classes of compounds: keto acids (pyruvic acid and homologs), hydroxy tricarboxylic acids (citric acid and homologs), and tricarboxylic acids. Laboratory syntheses using 13C-labeled reactants demonstrate that one compound alone, pyruvic acid, can produce several (nonenzymatic) members of the citric acid cycle including oxaloacetic acid. The isotopic composition of some of the meteoritic keto acids points to interstellar or presolar origins, indicating that such compounds might also exist in other planetary systems. PMID:21825143

  14. Modeling non-linear kinetics of hyperpolarized [1-(13)C] pyruvate in the crystalloid-perfused rat heart

    NARCIS (Netherlands)

    Mariotti, E.; Orton, M. R.; Eerbeek, O.; Ashruf, J. F.; Zuurbier, C. J.; Southworth, R.; Eykyn, T. R.

    2016-01-01

    Hyperpolarized (13)C MR measurements have the potential to display non-linear kinetics. We have developed an approach to describe possible non-first-order kinetics of hyperpolarized [1-(13)C] pyruvate employing a system of differential equations that agrees with the principle of conservation of mass

  15. Serum Glutamic-Oxaloacetic Transaminase (GOT) and Glutamic-Pyruvic Transaminase (GPT) Levels in Children and Adolescents with Intellectual Disabilities

    Science.gov (United States)

    Lin, Jin-Ding; Lin, Pei-Ying; Chen, Li-Mei; Fang, Wen-Hui; Lin, Lan-Ping; Loh, Ching-Hui

    2010-01-01

    The elevated serum glutamic-oxaloacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT) rate among people with intellectual disabilities (ID) is unknown and have not been sufficiently studies. The present paper aims to provide the profile of GOT and GPT, and their associated relationship with other biochemical levels of children or…

  16. The anaerobic chytridiomycete fungus Piromyces sp. E2 produces ethanol via pyruvate:formate lyase and an alcohol dehydrogenase E.

    NARCIS (Netherlands)

    Boxma, B.; Voncken, F.L.M.; Jannink, S.A.; Alen, T.A. van; Akhmanova, A.S.; Weelden, S.W. van; Hellemond, J.J. van; Ricard, G.N.S.; Huynen, M.A.; Tielens, A.G.; Hackstein, J.H.P.

    2004-01-01

    Anaerobic chytridiomycete fungi possess hydrogenosomes, which generate hydrogen and ATP, but also acetate and formate as end-products of a prokaryotic-type mixed-acid fermentation. Notably, the anaerobic chytrids Piromyces and Neocallimastix use pyruvate:formate lyase (PFL) for the catabolism of

  17. PERANAN FUNGI MIKORIZA ARBUSKULA, MIKROORGANISME PELARUT FOSFAT, RHIZOBIUM SP DAN ASAM HUMIK UNTUK MENINGKATKAN PERTUMBUHAN DAN PRODUKTIVITAS LEGUM Calopogonium mucunoides PADA TANAH LATOSOL DAN TAILING TAMBANG EMAS DI PT. ANEKA TAMBANG

    Directory of Open Access Journals (Sweden)

    - Karti

    2014-06-01

    Full Text Available Latosols soil conditions are poor in nutrients and tailing of gold mine contain heavy metal causes low productivity of forage. The objective of this research to study the best combination of soil potential microorganisms and soil conditioner that can promote the growth and production of legume crops Calopogonium mucunoides Desv. Seven treatments used were A: control, B: arbuscular mycorrhizal fungi (AMF, C: AMF + Rhizobium, D: AMF + Phosphate Solubilizing Bacteria (BPF, E: AMF + Humic Acid, F: AMF + BPF + Rhizobium, G: AMF + BPF + Humic Acid + Rhizobium. Variables measured were the root dry weight, shoot dry weight, spread length, number of trifoliate leaves, the number of active root nodules, the percentage of root infection. Augmentation of soil microorganisms and soil conditioner not effective enough to improve plant growth of Calopogonium mucunoides Desv because plants can still adapt and grow well on latosols. Plants grown on tailings provide the best response is G (AMF+ Humic Acid + Rhizobium, although the rate of growth is not as good as plants grown in latosols.

  18. The pyruvate kinase of Stigmatella aurantiaca is an indole binding protein and essential for development.

    Science.gov (United States)

    Stamm, Irmela; Lottspeich, Friedrich; Plaga, Wulf

    2005-06-01

    Myxospore formation of the myxobacterium Stigmatella aurantiaca can be uncoupled from the cooperative development i.e. fruiting body formation, by low concentrations of indole. Two putative indole receptor proteins were isolated by their capacity to bind indole and identified as pyruvate kinase (PK) and aldehyde dehydrogenase. The PK activity of Stigmatella crude extracts was stimulated by indole. Cloning of the PK gene (pykA) and the construction of a pykA disruption mutant strikingly revealed that PK is essential for multicellular development: Fruiting body formation was abolished in the mutant strain and indole-induced spore formation was delayed. The developmental defects could be complemented by insertion of the pykA gene at the mtaB locus of the Stigmatella genome excluding any polar effects of the pykA disruption.

  19. The effects of creatine pyruvate and creatine citrate on performance during high intensity exercise

    Directory of Open Access Journals (Sweden)

    Purpura Martin

    2008-02-01

    Full Text Available Abstract Background A double-blind, placebo-controlled, randomized study was performed to evaluate the effect of oral creatine pyruvate (Cr-Pyr and creatine citrate (Cr-Cit supplementation on exercise performance in healthy young athletes. Methods Performance during intermittent handgrip exercise of maximal intensity was evaluated before (pretest and after (posttest 28 days of Cr-Pyr (5 g/d, n = 16, Cr-Cit (5 g/d, n = 16 or placebo (pla, 5 g/d, n = 17 intake. Subjects performed ten 15-sec exercise intervals, each followed by 45 sec rest periods. Results Cr-Pyr (p Conclusion It is concluded that four weeks of Cr-Pyr and Cr-Cit intake significantly improves performance during intermittent handgrip exercise of maximal intensity and that Cr-Pyr might benefit endurance, due to enhanced activity of the aerobic metabolism.

  20. Effects of IL-6 on pyruvate dehydrogenase regulation in mouse skeletal muscle

    DEFF Research Database (Denmark)

    Biensø, Rasmus Sjørup; Knudsen, Jakob Grunnet; Brandt, Nina

    2014-01-01

    Skeletal muscle regulates substrate choice according to demand and availability and pyruvate dehydrogenase (PDH) is central in this regulation. Circulating interleukin (IL)-6 increases during exercise and IL-6 has been suggested to increase whole body fat oxidation. Furthermore, IL-6 has been...... reported to increase AMP-activated protein kinase (AMPK) phosphorylation and AMPK suggested to regulate PDHa activity. Together, this suggests that IL-6 may be involved in regulating PDH. The aim of this study was to investigate the effect of a single injection of IL-6 on PDH regulation in skeletal muscle...... in fed and fasted mice. Fed and 16-18 h fasted mice were injected with either 3 ng · g(-1) recombinant mouse IL-6 or PBS as control. Fasting markedly reduced plasma glucose, muscle glycogen, muscle PDHa activity, as well as increased PDK4 mRNA and protein content in skeletal muscle. IL-6 injection did...

  1. Novel Mutations in the PC Gene in Patients with Type B Pyruvate Carboxylase Deficiency

    DEFF Research Database (Denmark)

    Ostergaard, Elsebet; Duno, Morten; Møller, Lisbeth Birk

    2013-01-01

    We have investigated seven patients with the type B form of pyruvate carboxylase (PC) deficiency. Mutation analysis revealed eight mutations, all novel. In a patient with exon skipping on cDNA analysis, we identified a homozygous mutation located in a potential branch point sequence, the first...... possible branch point mutation in PC. Two patients were homozygous for missense mutations (with normal protein amounts on western blot analysis), and two patients were homozygous for nonsense mutations. In addition, a duplication of one base pair was found in a patient who also harboured a splice site...... mutation. Another splice site mutation led to the activation of a cryptic splice site, shown by cDNA analysis.All patients reported until now with at least one missense mutation have had the milder type A form of PC deficiency. We thus report for the first time two patients with homozygous missense...

  2. Protective effect of ethyl pyruvate on mice sperm parameters in phenylhydrazine induced hemolytic anemia.

    Science.gov (United States)

    Mozafari, Ali Akbar; Shahrooz, Rasoul; Ahmadi, Abbas; Malekinjad, Hassan; Mardani, Karim

    2016-01-01

    The aim of the present study was to assess the protective effect of ethyl pyruvate (EP) on sperm quality parameters, testosterone level and malondialdehyde (MDA) in phenylhydrazine (PHZ) treated mice. For this purpose, 32 NMRI mice with the age range of 8 to 10 weeks, weight average 26.0 ± 2.0 g, were randomly divided into four equal groups. The control group (1) received normal saline (0. 1 mL per day) by intraperitoneal injection (IP). Group 2 (PHZ group) was treated with initial dose of PHZ (8 mg 100 g(-1), IP) followed by 6 mg 100 g(-1) , IP every 48 hr. Group 3, (Group PHZ+EP) received PHZ (according to the previous prescription) with EP (40 mg kg(-1), daily, IP). Ethyl pyruvate group (4) received only EP (40 mg kg(-1), daily, IP). Treatment period was 35 days. After euthanasia, sperms from caudal region of epididymis were collected and the total mean sperm count, sperm viability, motility and morphology were determined. Testis tissue MDA and serum testosterone levels of all experimental groups were also evaluated. A considerable reduction in mean percentage of number, natural morphology of sperm, sperm motility and viability and serum testosterone concentration besides DNA injury increment among mice treating with PHZ in comparison with control group were observed. However, in PHZ+EP group the above mentioned parameters were improved. This study showed that PHZ caused induction of toxicity on sperm parameters and reduction of testosterone as well as the increment of MDA level and EP as an antioxidant could reduce destructive effects of PHZ on sperm parameters, testosterone level and lipid peroxidation.

  3. Monovalent Cation Activation of the Radical SAM Enzyme Pyruvate Formate-Lyase Activating Enzyme.

    Science.gov (United States)

    Shisler, Krista A; Hutcheson, Rachel U; Horitani, Masaki; Duschene, Kaitlin S; Crain, Adam V; Byer, Amanda S; Shepard, Eric M; Rasmussen, Ashley; Yang, Jian; Broderick, William E; Vey, Jessica L; Drennan, Catherine L; Hoffman, Brian M; Broderick, Joan B

    2017-08-30

    Pyruvate formate-lyase activating enzyme (PFL-AE) is a radical S-adenosyl-l-methionine (SAM) enzyme that installs a catalytically essential glycyl radical on pyruvate formate-lyase. We show that PFL-AE binds a catalytically essential monovalent cation at its active site, yet another parallel with B 12 enzymes, and we characterize this cation site by a combination of structural, biochemical, and spectroscopic approaches. Refinement of the PFL-AE crystal structure reveals Na + as the most likely ion present in the solved structures, and pulsed electron nuclear double resonance (ENDOR) demonstrates that the same cation site is occupied by 23 Na in the solution state of the as-isolated enzyme. A SAM carboxylate-oxygen is an M + ligand, and EPR and circular dichroism spectroscopies reveal that both the site occupancy and the identity of the cation perturb the electronic properties of the SAM-chelated iron-sulfur cluster. ENDOR studies of the PFL-AE/[ 13 C-methyl]-SAM complex show that the target sulfonium positioning varies with the cation, while the observation of an isotropic hyperfine coupling to the cation by ENDOR measurements establishes its intimate, SAM-mediated interaction with the cluster. This monovalent cation site controls enzyme activity: (i) PFL-AE in the absence of any simple monovalent cations has little-no activity; and (ii) among monocations, going down Group 1 of the periodic table from Li + to Cs + , PFL-AE activity sharply maximizes at K + , with NH 4 + closely matching the efficacy of K + . PFL-AE is thus a type I M + -activated enzyme whose M + controls reactivity by interactions with the cosubstrate, SAM, which is bound to the catalytic iron-sulfur cluster.

  4. Mechanistic photodecarboxylation of pyruvic acid: Excited-state proton transfer and three-state intersection

    Science.gov (United States)

    Chang, Xue-Ping; Fang, Qiu; Cui, Ganglong

    2014-10-01

    Photodissociation dynamics of pyruvic acid experimentally differs from that of commonly known ketones. We have employed the complete active space self-consistent field and its multi-state second-order perturbation methods to study its photodissociation mechanism in the S0, T1, and S1 states. We have uncovered four nonadiabatic photodecarboxylation paths. (i) The S1 system relaxes via an excited-state intramolecular proton transfer (ESIPT) to a hydrogen-transferred tautomer, near which an S1/S0 conical intersection funnels the S1 to S0 state. Then, some trajectories continue completing the decarboxylation reaction in the S0 state; the remaining trajectories via a reverse hydrogen transfer return to the S0 minimum, from which a thermal decarboxylation reaction occurs. (ii) Due to a small S1 -T1 energy gap and a large S1/T1 spin-orbit coupling, an efficient S1 → T1 intersystem crossing process happens again near this S1/S0 conical intersection. When decaying to T1 state, a direct photodecarboxylation proceeds. (iii) Prior to ESIPT, the S1 system first decays to the T1 state via an S1 → T1 intersystem crossing; then, the T1 system evolves to a hydrogen-transferred tautomer. Therefrom, an adiabatic T1 decarboxylation takes place due to a small barrier of 7.7 kcal/mol. (iv) Besides the aforementioned T1 ESIPT process, there also exists a comparable Norrish type I reaction in the T1 state, which forms the ground-state products of CH3CO and COOH. Finally, we have found that ESIPT plays an important role. It closes the S1-T1 and S1-S0 energy gaps, effecting an S1/T1/S0 three-state intersection region, and mediating nonadiabatic photodecarboxylation reactions of pyruvic acid.

  5. In vitro bioconversion of chitin to pyruvate with thermophilic enzymes.

    Science.gov (United States)

    Honda, Kohsuke; Kimura, Keisuke; Ninh, Pham Huynh; Taniguchi, Hironori; Okano, Kenji; Ohtake, Hisao

    2017-09-01

    Chitin is the second most abundant organic compound on the planet and thus has been regarded as an alternative resource to petroleum feedstocks. One of the key challenges in the biological conversion of biomass-derived polysaccharides, such as cellulose and chitin, is to close the gap between optimum temperatures for enzymatic saccharification and microbial fermentation and to implement them in a single bioreactor. To address this issue, in the present study, we aimed to perform an in vitro, one-pot bioconversion of chitin to pyruvate, which is a precursor of a wide range of useful metabolites. Twelve thermophilic enzymes, including that for NAD + regeneration, were heterologously produced in Escherichia coli and semi-purified by heat treatment of the crude extract of recombinant cells. When the experimentally decided concentrations of enzymes were incubated with 0.5 mg mL -1 colloidal chitin (equivalent to 2.5 mM N-acetylglucosamine unit) and an adequate set of cofactors at 70°C, 0.62 mM pyruvate was produced in 5 h. Despite the use of a cofactor-balanced pathway, determination of the pool sizes of cofactors showed a rapid decrease in ATP concentration, most probably due to the thermally stable ATP-degrading enzyme(s) derived from the host cell. Integration of an additional enzyme set of thermophilic adenylate kinase and polyphosphate kinase led to the deceleration of ATP degradation, and the final product titer was improved to 2.1 mM. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  6. Et kors er ikke bare et kors

    DEFF Research Database (Denmark)

    Bach-Nielsen, Carsten

    2015-01-01

    Om et kors, der er rejst uden for den danske kirke i Bruxelles; formodentlig en afledning af det såkaldte Brabanterkors.......Om et kors, der er rejst uden for den danske kirke i Bruxelles; formodentlig en afledning af det såkaldte Brabanterkors....

  7. Persistent changes in the initial rate of pyruvate transport by isolated rat liver mitochondria after preincubation with adenine nucleotides and calcium ions

    OpenAIRE

    Vaartjes, W.J.; Breejen, J.N. den; Geelen, M.J.H.; Bergh, S.G. van den

    1980-01-01

    1. Preincubation of isolated rat-liver mitochondria in the presence of adenine nucleotides or Ca2+ results in definite and persistent changes in the initial rate of pyruvate transport. 2. These changes in the rate of pyruvate transport are accompanied by equally persistent changes in the opposite direction of the activity of pyruvate dehydrogenase (EC. 1.2.4.1). 3. Changes of the transmembrane pH gradient and of the membrane potential, brought about by the pretreatments of the mitochondria, c...

  8. Bankole et al (2)

    African Journals Online (AJOL)

    DELL

    Relationships of Clay-filled Channels on the Delta Flanks (Modified after Doust and Omatsola, 1990 and Lawrence et al., 2002). ... and in the Indo-Malaysian area (Germeraad et al.,. 1968). The genus ..... Upper Cretaceous of British Guiana.

  9. [Formation and function of the bean-rhizobium symbiosis in soy plants upon introduction of strains of Azotobacter and Bacillus species].

    Science.gov (United States)

    Mel'nikova, N N; Bulavenko, L V; Kurdish, I K; Titova, L V; Kots', S Ia

    2002-01-01

    The effects of bacteria belonging to the genera Azotobacter and Bacillus in a mixed culture with Bradyrhizobium japonicum strains on formation and function of the legume-rhizobium symbiosis of soybean plants were studied. The data showed that the bacterial compositions B. japonicum 634b + B. subtilis 5, B. japonicum 634b + A. chroococcum 20, and B. japonicum 10k + A. vinelandii 56 with a cell ratio of 1:0.1 increased the number and weight of root nodules as well as the height and weight of the aboveground plant parts in almost all the cases by 22-105% compared with the control variants. These binary microbial cultures may be used for development of combined bacterial preparations for soybean.

  10. Rhizobium promotes non-legumes growth and quality in several production steps: towards a biofertilization of edible raw vegetables healthy for humans.

    Directory of Open Access Journals (Sweden)

    Paula García-Fraile

    Full Text Available The biofertilization of crops with plant-growth-promoting microorganisms is currently considered as a healthy alternative to chemical fertilization. However, only microorganisms safe for humans can be used as biofertilizers, particularly in vegetables that are raw consumed, in order to avoid sanitary problems derived from the presence of pathogenic bacteria in the final products. In the present work we showed that Rhizobium strains colonize the roots of tomato and pepper plants promoting their growth in different production stages increasing yield and quality of seedlings and fruits. Our results confirmed those obtained in cereals and alimentary oil producing plants extending the number of non-legumes susceptible to be biofertilized with rhizobia to those whose fruits are raw consumed. This is a relevant conclusion since safety of rhizobia for human health has been demonstrated after several decades of legume inoculation ensuring that they are optimal bacteria for biofertilization.

  11. Co-inoculation with Rhizobium and plant growth promoting rhizobacteria (PGPR for inducing salinity tolerance in mung bean under field condition of semi arid climate

    Directory of Open Access Journals (Sweden)

    Muhammad Aamir

    2013-04-01

    Full Text Available Salinity stress severely affects the growth, nodulation and yield of mung bean (Vigna radiata L.. However, its growth can be improved under salinity stress by inoculation/co-inoculation with rhizobia and plant growth promoting rhizobacteria (PGPR containing 1-Aminocyclopropane-1-carboxylic acid (ACC deaminase enzyme. ACC-deaminase containing bacteria regulate the stress induced ethylene production by hydrolyzing the ACC (immediate precursor of ethylene into ammonia and ketobutyric acid, thus improve plant growth by lowering the ethylene level. A study was conducted under salt affected field conditions where pre-isolated strains of Rhizobium and PGPR were used alone as well as in combination for mitigating the salinity stress on growth, nodulation and yield of mung bean by following the randomized complete block design (RCBD. The data were recorded and analyzed statistically to see the difference among treatments.

  12. Pyruvate dehydrogenase complex and lactate dehydrogenase as targets for therapy of acute liver failure.

    Science.gov (United States)

    Ferriero, Rosa; Nusco, Edoardo; De Cegli, Rossella; Carissimo, Annamaria; Manco, Giuseppe; Brunetti-Pierri, Nicola

    2018-03-23

    Acute liver failure is a rapidly progressive deterioration of hepatic function resulting in high mortality and morbidity. Metabolic enzymes can translocate in the nucleus to regulate histone acetylation and gene expression. Levels and activities of pyruvate dehydrogenase complex (PDHC) and lactate dehydrogenase (LDH) were evaluated in nuclear fractions of livers of mice exposed to various hepatotoxins including CD95-Ab, α-amanitin, and acetaminophen. Whole-genome gene expression profiling by RNA-seq was performed in livers of mice with acute liver failure and analyzed by Gene Ontology Enrichment Analysis. Efficacy of histone acetyltransferase inhibitor garcinol and LDH inhibitor galloflavin at reducing liver damage was evaluated in mice with induced hepatotoxicity. Levels and activities of PDHC and LDH were increased in cytoplasmatic and nuclear fractions of livers of mice with acute liver failure. The increase of nuclear PDHC and LDH was associated with increased concentrations of acetyl-coA and lactate in nuclear fractions, and histone H3 hyper-acetylation. Gene expression in livers of mice with acute liver failure suggested that increased histone H3 acetylation induces the expression of genes related to response to damage. Reduced histone acetylation by the histone acetyltransferase inhibitor garcinol decreased liver damage and improved survival in mice with acute liver failure. Knock-down of PDHC or LDH improved viability in cells exposed to a pro-apoptotic stimulus. Treatment with the LDH inhibitor galloflavin that was also found to inhibit PDHC, reduced hepatic necrosis, apoptosis, and expression of pro-inflammatory cytokines in mice with acute liver failure. Mice treated with galloflavin also showed a dose-response increase in survival. PDHC and LDH translocate to the nucleus and are targets for therapy of acute liver failure. Acute liver failure is a rapidly progressive and life-threatening deterioration of liver function resulting in high mortality and

  13. Mechanistic photodecarboxylation of pyruvic acid: Excited-state proton transfer and three-state intersection

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Xue-Ping; Fang, Qiu, E-mail: fangqiu917@bnu.edu.cn; Cui, Ganglong, E-mail: ganglong.cui@bnu.edu.cn [Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875 (China)

    2014-10-21

    Photodissociation dynamics of pyruvic acid experimentally differs from that of commonly known ketones. We have employed the complete active space self-consistent field and its multi-state second-order perturbation methods to study its photodissociation mechanism in the S{sub 0}, T{sub 1}, and S{sub 1} states. We have uncovered four nonadiabatic photodecarboxylation paths. (i) The S{sub 1} system relaxes via an excited-state intramolecular proton transfer (ESIPT) to a hydrogen-transferred tautomer, near which an S{sub 1}/S{sub 0} conical intersection funnels the S{sub 1} to S{sub 0} state. Then, some trajectories continue completing the decarboxylation reaction in the S{sub 0} state; the remaining trajectories via a reverse hydrogen transfer return to the S{sub 0} minimum, from which a thermal decarboxylation reaction occurs. (ii) Due to a small S{sub 1} −T{sub 1} energy gap and a large S{sub 1}/T{sub 1} spin-orbit coupling, an efficient S{sub 1} → T{sub 1} intersystem crossing process happens again near this S{sub 1}/S{sub 0} conical intersection. When decaying to T{sub 1} state, a direct photodecarboxylation proceeds. (iii) Prior to ESIPT, the S{sub 1} system first decays to the T{sub 1} state via an S{sub 1} → T{sub 1} intersystem crossing; then, the T{sub 1} system evolves to a hydrogen-transferred tautomer. Therefrom, an adiabatic T{sub 1} decarboxylation takes place due to a small barrier of 7.7 kcal/mol. (iv) Besides the aforementioned T{sub 1} ESIPT process, there also exists a comparable Norrish type I reaction in the T{sub 1} state, which forms the ground-state products of CH{sub 3}CO and COOH. Finally, we have found that ESIPT plays an important role. It closes the S{sub 1}-T{sub 1} and S{sub 1}-S{sub 0} energy gaps, effecting an S{sub 1}/T{sub 1}/S{sub 0} three-state intersection region, and mediating nonadiabatic photodecarboxylation reactions of pyruvic acid.

  14. Single acquisition of protelomerase gave rise to speciation of a large and diverse clade within the Agrobacterium/Rhizobium supercluster characterized by the presence of a linear chromid.

    Science.gov (United States)

    Ramírez-Bahena, Martha H; Vial, Ludovic; Lassalle, Florent; Diel, Benjamin; Chapulliot, David; Daubin, Vincent; Nesme, Xavier; Muller, Daniel

    2014-04-01

    Linear chromosomes are atypical in bacteria and likely a secondary trait derived from ancestral circular molecules. Within the Rhizobiaceae family, whose genome contains at least two chromosomes, a particularity of Agrobacterium fabrum (formerly A. tumefaciens) secondary chromosome (chromid) is to be linear and hairpin-ended thanks to the TelA protelomerase. Linear topology and telA distributions within this bacterial family was screened by pulse field gel electrophoresis and PCR. In A. rubi, A. larrymoorei, Rhizobium skierniewicense, A. viscosum, Agrobacterium sp. NCPPB 1650, and every genomospecies of the biovar 1/A. tumefaciens species complex (including R. pusense, A. radiobacter, A. fabrum, R. nepotum plus seven other unnamed genomospecies), linear chromid topologies were retrieved concomitantly with telA presence, whereas the remote species A. vitis, Allorhizobium undicola, Rhizobium rhizogenes and Ensifer meliloti harbored a circular chromid as well as no telA gene. Moreover, the telA phylogeny is congruent with that of recA used as a marker gene of the Agrobacterium phylogeny. Collectively, these findings strongly suggest that single acquisition of telA by an ancestor was the founding event of a large and diverse clade characterized by the presence of a linear chromid. This clade, characterized by unusual genome architecture, appears to be a relevant candidate to serve as a basis for a possible redefinition of the controversial Agrobacterium genus. In this respect, investigating telA in sequenced genomes allows to both ascertain the place of concerned strains into Agrobacterium spp. and their actual assignation to species/genomospecies in this genus. Copyright © 2014 Elsevier Inc. All rights reserved.

  15. Mutation of a Broadly Conserved Operon (RL3499-RL3502) from Rhizobium leguminosarum Biovar viciae Causes Defects in Cell Morphology and Envelope Integrity▿†

    Science.gov (United States)

    Vanderlinde, Elizabeth M.; Magnus, Samantha A.; Tambalo, Dinah D.; Koval, Susan F.; Yost, Christopher K.

    2011-01-01

    The bacterial cell envelope is of critical importance to the function and survival of the cell; it acts as a barrier against harmful toxins while allowing the flow of nutrients into the cell. It also serves as a point of physical contact between a bacterial cell and its host. Hence, the cell envelope of Rhizobium leguminosarum is critical to cell survival under both free-living and symbiotic conditions. Transposon mutagenesis of R. leguminosarum strain 3841 followed by a screen to isolate mutants with defective cell envelopes led to the identification of a novel conserved operon (RL3499-RL3502) consisting of a putative moxR-like AAA+ ATPase, a hypothetical protein with a domain of unknown function (designated domain of unknown function 58), and two hypothetical transmembrane proteins. Mutation of genes within this operon resulted in increased sensitivity to membrane-disruptive agents such as detergents, hydrophobic antibiotics, and alkaline pH. On minimal media, the mutants retain their rod shape but are roughly 3 times larger than the wild type. On media containing glycine or peptides such as yeast extract, the mutants form large, distorted spheres and are incapable of sustained growth under these culture conditions. Expression of the operon is maximal during the stationary phase of growth and is reduced in a chvG mutant, indicating a role for this sensor kinase in regulation of the operon. Our findings provide the first functional insight into these genes of unknown function, suggesting a possible role in cell envelope development in Rhizobium leguminosarum. Given the broad conservation of these genes among the Alphaproteobacteria, the results of this study may also provide insight into the physiological role of these genes in other Alphaproteobacteria, including the animal pathogen Brucella. PMID:21357485

  16. Characterization and functional analysis of seven flagellin genes in Rhizobium leguminosarum bv. viciae. Characterization of R. leguminosarum flagellins

    Directory of Open Access Journals (Sweden)

    Tambalo Dinah D

    2010-08-01

    Full Text Available Abstract Background Rhizobium leguminosarum bv. viciae establishes symbiotic nitrogen fixing partnerships with plant species belonging to the Tribe Vicieae, which includes the genera Vicia, Lathyrus, Pisum and Lens. Motility and chemotaxis are important in the ecology of R. leguminosarum to provide a competitive advantage during the early steps of nodulation, but the mechanisms of motility and flagellar assembly remain poorly studied. This paper addresses the role of the seven flagellin genes in producing a functional flagellum. Results R. leguminosarum strains 3841 and VF39SM have seven flagellin genes (flaA, flaB, flaC, flaD, flaE, flaH, and flaG, which are transcribed separately. The predicted flagellins of 3841 are highly similar or identical to the corresponding flagellins in VF39SM. flaA, flaB, flaC, and flaD are in tandem array and are located in the main flagellar gene cluster. flaH and flaG are located outside of the flagellar/motility region while flaE is plasmid-borne. Five flagellin subunits (FlaA, FlaB, FlaC, FlaE, and FlaG are highly similar to each other, whereas FlaD and FlaH are more distantly related. All flagellins exhibit conserved amino acid residues at the N- and C-terminal ends and are variable in the central regions. Strain 3841 has 1-3 plain subpolar flagella while strain VF39SM exhibits 4-7 plain peritrichous flagella. Three flagellins (FlaA/B/C and five flagellins (FlaA/B/C/E/G were detected by mass spectrometry in the flagellar filaments of strains 3841 and VF39SM, respectively. Mutation of flaA resulted in non-motile VF39SM and extremely reduced motility in 3841. Individual mutations of flaB and flaC resulted in shorter flagellar filaments and consequently reduced swimming and swarming motility for both strains. Mutant VF39SM strains carrying individual mutations in flaD, flaE, flaH, and flaG were not significantly affected in motility and filament morphology. The flagellar filament and the motility of 3841 strains

  17. Data regarding the growth of Lactobacillus acidophilus NCFM on different carbohydrates and recombinant production of elongation factor G and pyruvate kinase

    DEFF Research Database (Denmark)

    Celebioglu, Hasan Ufuk; Olesen, Sita Vaag; Prehn, Kennie

    2017-01-01

    The present study describes the growth of the very well-known probiotic bacterium Lactobacillus acidophilus NCFM on different carbohydrates. Furthermore, recombinant production of putative moonlighting proteins elongation factor G and pyruvate kinase from this bacterium is described. For further...

  18. Increased expression of pyruvate carboxylase and biotin protein ligase increases lysine production in a biotin prototrophic Corynebacterium glutamicum strain

    DEFF Research Database (Denmark)

    Wang, Zhihao; Moslehi-Jenabian, Soloomeh; Solem, Christian

    2015-01-01

    , and achieved biotin prototrophy. We found that AHP-3, containing pBIO, was able to produce lysine in a medium lacking biotin and that the lysine yield on glucose was similar to what is obtained when using a medium containing biotin. However, there was a decrease in specific growth rate of 20% when the strain...... pimeloyl-Acyl Carrier Protein [ACP]) formation. Pyruvate carboxylase (pycA), a biotin-dependent enzyme needed for lysine biosynthesis and biotin ligase (birA), which is responsible for attaching biotin to pyruvate carboxylase, were overexpressed by replacing the native promoters with the strong superoxide...... dismutase (sod) promoter, to see whether growth could be restored. Neither pycA nor birA overexpression, whether alone or in combination, had an effect on specific growth rate, but they did have a positive effect on lysine yield, which increased by 55% in the strain overexpressing both enzymes....

  19. Formation and utilization of acetoin, an unusual product of pyruvate metabolism by Ehrlich and AS30-D tumor mitochondria.

    Science.gov (United States)

    Baggetto, L G; Lehninger, A L

    1987-07-15

    [14C]Pyruvate was rapidly non-oxidatively decarboxylated by Ehrlich tumor mitochondria at a rate of 40 nmol/min/mg of protein in the presence or absence of ADP. A search for decarboxylation products led to significant amounts of acetoin formed when Ehrlich tumor mitochondria were incubated with 1 mM [14C] pyruvate in the presence of ATP. Added acetoin to aerobic tumor mitochondria was rapidly utilized in the presence of ATP at a rate of 65 nmol/min/mg of protein. Citrate has been found as a product of acetoin utilization and was exported from the tumor mitochondria. Acetoin has been found in the ascitic liquid of Ehrlich and AS30-D tumor-bearing animals. These unusual reactions were not observed in control rat liver mitochondria.

  20. Blood glucose, lactate, pyruvate, glycerol, 3-hydroxybutyrate and acetoacetate measurements in man using a centrifugal analyser with a fluorimetric attachment.

    Science.gov (United States)

    Harrison, J; Hodson, A W; Skillen, A W; Stappenbeck, R; Agius, L; Alberti, K G

    1988-03-01

    Methods are described for the analysis of glucose, lactate, pyruvate, alanine, glycerol, 3-hydroxybutyrate and acetoacetate in perchloric acid extracts of human blood, using the Cobas Bio centrifugal analyser fitted with a fluorimetric attachment. Intra-assay and inter-assay coefficients of variation ranged from 1.9 to 7.9% and from 1.0 to 7.2% respectively. Correlation coefficients ranged from 0.96 to 0.99 against established continuous-flow and manual spectrophotometric methods. All seven metabolites can be measured using a single perchloric acid extract of 20 microliter of blood. The versatility of the assays is such that as little as 100 pmol pyruvate, 3-hydroxybutyrate or as much as 15 nmol glucose can be measured in the same 20 microliter extract.

  1. Pyruvic Oxime Nitrification and Copper and Nickel Resistance by a Cupriavidus pauculus, an Active Heterotrophic Nitrifier-Denitrifier

    OpenAIRE

    Ramirez, Miguel; Obrzydowski, Jennifer; Ayers, Mary; Virparia, Sonia; Wang, Meijing; Stefan, Kurtis; Linchangco, Richard; Castignetti, Domenic

    2014-01-01

    Heterotrophic nitrifiers synthesize nitrogenous gasses when nitrifying ammonium ion. A Cupriavidus pauculus, previously thought an Alcaligenes sp. and noted as an active heterotrophic nitrifier-denitrifier, was examined for its ability to produce nitrogen gas (N2) and nitrous oxide (N2O) while heterotrophically nitrifying the organic substrate pyruvic oxime [CH3–C(NOH)–COOH]. Neither N2 nor N2O were produced. Nucleotide and phylogenetic analyses indicated that the organism is a member of a g...

  2. Performance during a strenuous swimming session is associated with high blood lactate: pyruvate ratio and hypoglycemia in fasted rats.

    Science.gov (United States)

    Travassos, P B; Godoy, G; De Souza, H M; Curi, R; Bazotte, R B

    2018-03-26

    The aim of this study was to investigate the effect of lactatemia elevation and glycemia reduction on strenuous swimming performance in fasted rats. Three rats were placed in a swimming tank at the same time. The first rat was removed immediately (control group) and the remaining ones were submitted to a strenuous swimming session. After the second rat was exhausted (Exh group), the third one was immediately removed from the water (Exe group). According to the period of time required for exhaustion, the rats were divided into four groups: low performance (3-7 min), low-intermediary performance (8-12 min), high-intermediary performance (13-17 min), and high performance (18-22 min). All rats were removed from the swimming tanks and immediately killed by decapitation for blood collection or anesthetized for liver perfusion experiments. Blood glucose, lactate, and pyruvate concentrations, blood lactate/pyruvate ratio, and liver lactate uptake and its conversion to glucose were evaluated. Exhaustion in low and low-intermediary performance were better associated with higher lactate/pyruvate ratio. On the other hand, exhaustion in high-intermediary and high performance was better associated with hypoglycemia. Lactate uptake and glucose production from lactate in livers from the Exe and Exh groups were maintained. We concluded that there is a time sequence in the participation of lactate/pyruvate ratio and hypoglycemia in performance during an acute strenuous swimming section in fasted rats. The liver had an important participation in preventing hyperlactatemia and hypoglycemia during swimming through lactate uptake and its conversion to glucose.

  3. Effects of insulin on perfused liver from streptozotocin-diabetic and untreated rats: 13C NMR assay of pyruvate kinase flux

    International Nuclear Information System (INIS)

    Cohen, S.M.

    1987-01-01

    The effects of insulin in vitro on perfused liver from streptozotocin-diabetic rats and their untreated littermates during gluconeogenesis from either [3- 13 C]alanine + ethanol or [2- 13 C]pyruvate + NH 4 Cl + ethanol were studied by 13 C NMR. A 13 C NMR determination of the rate of pyruvate kinase flux under steady-state conditions of active gluconeogenesis was developed; this assay includes a check on the reuse of recycled pyruvate. The preparations studied provided gradations of pyruvate kinase flux within the confines of the assay's requirement of active gluconeogenesis. By this determination, the rate of pyruvate kinase flux was 0.74 +/- 0.04 of the gluconeogenic rate in liver from 24-h-fasted controls; in liver from 12-h fasted controls, relative pyruvate kinase flux increased to 1.0 +/- 0.2. In diabetic liver, this flux was undetectable by the authors NMR method. Insulin's hepatic influence in vitro was greatest in the streptozotocin model of type 1 diabetes: upon treatment of diabetic liver with 7 nM insulin in vitro, a partial reversal of many of the differences noted between diabetic and control liver was demonstrated by 13 C NMR. A major effect of insulin in vitro upon diabetic liver was the induction of a large increase in the rate of pyruvate kinase flux, bringing relative and absolute fluxes up to the levels measured in 24-h-fasted controls. By way of comparison, the effects of ischemia on diabetic liver were studied by 13 C NMR to test whether changes in allosteric effectors under these conditions could also increase pyruvate kinase flux. A large increase in this activity was demonstrated in ischemic diabetic liver

  4. Identification of the protein responsible for pyruvate transport into rat liver and heart mitochondria by specific labelling with [3H]N-phenylmaleimide.

    OpenAIRE

    Thomas, A P; Halestrap, A P

    1981-01-01

    1. N-Phenylmaleimide irreversibly inhibits pyruvate transport into rat heart and liver mitochondria to a much greater extent than does N-ethylmaleimide, iodoacetate or bromopyruvate. alpha-Cyanocinnamate protects the pyruvate transporter from attack by this thiol-blocking reagent. 2. In both heart and liver mitochondria alpha-cyanocinnamate diminishes labelling by [3H]N-phenylmaleimide of a membrane protein of subunit mol.wt. 15000 on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis...

  5. Application of mitochondrial pyruvate carrier blocker UK5099 creates metabolic reprogram and greater stem-like properties in LnCap prostate cancer cells in vitro

    OpenAIRE

    Zhong, Yali; Li, Xiaoran; Yu, Dandan; Li, Xiaoli; Li, Yaqing; Long, Yuan; Yuan, Yuan; Ji, Zhenyu; Zhang, Mingzhi; Wen, Jian-Guo; Nesland, Jahn M.; Suo, Zhenhe

    2015-01-01

    Aerobic glycolysis is one of the important hallmarks of cancer cells and eukaryotic cells. In this study, we have investigated the relationship between blocking mitochondrial pyruvate carrier (MPC) with UK5099 and the metabolic alteration as well as stemness phenotype of prostatic cancer cells. It was found that blocking pyruvate transportation into mitochondrial attenuated mitochondrial oxidative phosphorylation (OXPHOS) and increased glycolysis. The UK5099 treated cells showed significantly...

  6. Role of pyruvate dehydrogenase inhibition in the development of hypertrophy in the hyperthyroid rat heart: a combined magnetic resonance imaging and hyperpolarized magnetic resonance spectroscopy study.

    Science.gov (United States)

    Atherton, Helen J; Dodd, Michael S; Heather, Lisa C; Schroeder, Marie A; Griffin, Julian L; Radda, George K; Clarke, Kieran; Tyler, Damian J

    2011-06-07

    Hyperthyroidism increases heart rate, contractility, cardiac output, and metabolic rate. It is also accompanied by alterations in the regulation of cardiac substrate use. Specifically, hyperthyroidism increases the ex vivo activity of pyruvate dehydrogenase kinase, thereby inhibiting glucose oxidation via pyruvate dehydrogenase. Cardiac hypertrophy is another effect of hyperthyroidism, with an increase in the abundance of mitochondria. Although the hypertrophy is initially beneficial, it can eventually lead to heart failure. The aim of this study was to use hyperpolarized magnetic resonance spectroscopy to investigate the rate and regulation of in vivo pyruvate dehydrogenase flux in the hyperthyroid heart and to establish whether modulation of flux through pyruvate dehydrogenase would alter cardiac hypertrophy. Hyperthyroidism was induced in 18 male Wistar rats with 7 daily intraperitoneal injections of freshly prepared triiodothyronine (0.2 mg x kg(-1) x d(-1)). In vivo pyruvate dehydrogenase flux, assessed with hyperpolarized magnetic resonance spectroscopy, was reduced by 59% in hyperthyroid animals (0.0022 ± 0.0002 versus 0.0055 ± 0.0005 second(-1); P=0.0003), and this reduction was completely reversed by both short- and long-term delivery of dichloroacetic acid, a pyruvate dehydrogenase kinase inhibitor. Hyperpolarized [2-(13)C]pyruvate was also used to evaluate Krebs cycle metabolism and demonstrated a unique marker of anaplerosis, the level of which was significantly increased in the hyperthyroid heart. Cine magnetic resonance imaging showed that long-term dichloroacetic acid treatment significantly reduced the hypertrophy observed in hyperthyroid animals (100 ± 20 versus 200 ± 30 mg; P=0.04) despite no change in the increase observed in cardiac output. This work has demonstrated that inhibition of glucose oxidation in the hyperthyroid heart in vivo is mediated by pyruvate dehydrogenase kinase. Relieving this inhibition can increase the metabolic

  7. Optimized methods to measure acetoacetate, 3-hydroxybutyrate, glycerol, alanine, pyruvate, lactate and glucose in human blood using a centrifugal analyser with a fluorimetric attachment

    OpenAIRE

    Stappenbeck, R.; Hodson, A. W.; Skillen, A. W.; Agius, L.; Alberti, K. G. M. M.

    1990-01-01

    Optimized methods are described for the analysis of glucose, lactate, pyruvate, alanine, glycerol, D-3-hydroxybutyrate and acetoacetate in perchloric acid extracts of human blood using the Cobas Bio centrifugal analyser. Glucose and lactate are measured using the photometric mode and other metabolites using the fluorimetric mode. The intra-assay coefficients of variation ranged from 0.7 to 4.1%, except with very low levels of pyruvate and acetoacetate where the coefficients of variation were ...

  8. Crystallization and preliminary X-ray analysis of dihydrodipicolinate synthase from Clostridium botulinum in the presence of its substrate pyruvate

    International Nuclear Information System (INIS)

    Atkinson, Sarah C.; Dobson, Renwick C. J.; Newman, Janet M.; Gorman, Michael A.; Dogovski, Con; Parker, Michael W.; Perugini, Matthew A.

    2009-01-01

    Dihydrodipicolinate synthase (DHDPS) catalyzes an important step in lysine biosynthesis. Here, the crystallization and preliminary diffraction analysis to 1.2 Å resolution of DHDPS from C. botulinum in the presence of its substrate pyruvate is reported. In this paper, the crystallization and preliminary X-ray diffraction analysis to near-atomic resolution of DHDPS from Clostridium botulinum crystallized in the presence of its substrate pyruvate are presented. The enzyme crystallized in a number of forms using a variety of PEG precipitants, with the best crystal diffracting to 1.2 Å resolution and belonging to space group C2, in contrast to the unbound form, which had trigonal symmetry. The unit-cell parameters were a = 143.4, b = 54.8, c = 94.3 Å, β = 126.3°. The crystal volume per protein weight (V M ) was 2.3 Å 3 Da −1 (based on the presence of two monomers in the asymmetric unit), with an estimated solvent content of 46%. The high-resolution structure of the pyruvate-bound form of C. botulinum DHDPS will provide insight into the function and stability of this essential bacterial enzyme

  9. Scanning mutagenesis of the amino acid sequences flanking phosphorylation site 1 of the mitochondrial pyruvate dehydrogenase complex

    Directory of Open Access Journals (Sweden)

    Nagib eAhsan

    2012-07-01

    Full Text Available The mitochondrial pyruvate dehydrogenase complex is regulated by reversible seryl-phosphorylation of the E1α subunit by a dedicated, intrinsic kinase. The phospho-complex is reactivated when dephosphorylated by an intrinsic PP2C-type protein phosphatase. Both the position of the phosphorylated Ser-residue and the sequences of the flanking amino acids are highly conserved. We have used the synthetic peptide-based kinase client assay plus recombinant pyruvate dehydrogenase E1α and E1α-kinase to perform scanning mutagenesis of the residues flanking the site of phosphorylation. Consistent with the results from phylogenetic analysis of the flanking sequences, the direct peptide-based kinase assays tolerated very few changes. Even conservative changes such as Leu, Ile, or Val for Met, or Glu for Asp, gave very marked reductions in phosphorylation. Overall the results indicate that regulation of the mitochondrial pyruvate dehydrogenase complex by reversible phosphorylation is an extreme example of multiple, interdependent instances of co-evolution.

  10. Pyruvate remediation of cell stress and genotoxicity induced by haloacetic acid drinking water disinfection by-products.

    Science.gov (United States)

    Dad, Azra; Jeong, Clara H; Pals, Justin A; Wagner, Elizabeth D; Plewa, Michael J

    2013-10-01

    Monohaloacetic acids (monoHAAs) are a major class of drinking water disinfection by-products (DBPs) and are cytotoxic, genotoxic, mutagenic, and teratogenic. We propose a model of toxic action based on monoHAA-mediated inhibition of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as a target cytosolic enzyme. This model predicts that GAPDH inhibition by the monoHAAs will lead to a severe reduction of cellular ATP levels and repress the generation of pyruvate. A loss of pyruvate will lead to mitochondrial stress and genomic DNA damage. We found a concentration-dependent reduction of ATP in Chinese hamster ovary cells after monoHAA treatment. ATP reduction per pmol monoHAA followed the pattern of iodoacetic acid (IAA) > bromoacetic acid (BAA) > chloroacetic acid (CAA), which is the pattern of potency observed with many toxicological endpoints. Exogenous supplementation with pyruvate enhanced ATP levels and attenuated monoHAA-induced genomic DNA damage as measured with single cell gel electrophoresis. These data were highly correlated with the SN 2 alkylating potentials of the monoHAAs and with the induction of toxicity. The results from this study strongly support the hypothesis that GAPDH inhibition and the possible subsequent generation of reactive oxygen species is linked with the cytotoxicity, genotoxicity, teratogenicity, and neurotoxicity of these DBPs. Copyright © 2013 Wiley Periodicals, Inc.

  11. Coordination of manganous ion at the active site of pyruvate, phosphate dikinase: the complex of oxalate with the phosphorylated enzyme

    International Nuclear Information System (INIS)

    Kofron, J.L.; Ash, D.E.; Reed, G.H.

    1988-01-01

    Electron paramagnetic resonance spectroscopy has been used to investigate the structure of the complex of manganous ion with the phosphorylated form of pyruvate, phosphate dikinase (E/sub p/) and the inhibitor oxalate. Oxalate, an analogue of the enolate of pyruvate, is competitive with respect to pyruvate in binding to the phosphorylated form of the enzyme. Superhyperfine coupling between the unpaired electrons of Mn(I) and ligands specifically labeled with 17 O has been used to identify oxygen ligands to Mn(II) in the complex with oxalate and the phosphorylated form of the enzyme. Oxalate binds at the active site as a bidentate chelate with Mn(II). An oxygen from the 3'-N-phosphohistidyl residue of the protein is in the coordination sphere of Mn(II), and at least two water molecules are also bound to Mn(II) in the complex. Oxalate also binds directly to Mn(II) in a complex with nonphosphorylated enzyme. The structure for the E/sub p/-Mn(II)-oxalate complex implies that simultaneous coordination of a phospho group and of the attacking nucleophile to the divalent cation is likely an important factor in catalysis of this phospho-transfer reaction

  12. Identification of a mitochondrial target of thiazolidinedione insulin sensitizers (mTOT--relationship to newly identified mitochondrial pyruvate carrier proteins.

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    Jerry R Colca

    Full Text Available Thiazolidinedione (TZD insulin sensitizers have the potential to effectively treat a number of human diseases, however the currently available agents have dose-limiting side effects that are mediated via activation of the transcription factor PPARγ. We have recently shown PPARγ-independent actions of TZD insulin sensitizers, but the molecular target of these molecules remained to be identified. Here we use a photo-catalyzable drug analog probe and mass spectrometry-based proteomics to identify a previously uncharacterized mitochondrial complex that specifically recognizes TZDs. These studies identify two well-conserved proteins previously known as brain protein 44 (BRP44 and BRP44 Like (BRP44L, which recently have been renamed Mpc2 and Mpc1 to signify their function as a mitochondrial pyruvate carrier complex. Knockdown of Mpc1 or Mpc2 in Drosophila melanogaster or pre-incubation with UK5099, an inhibitor of pyruvate transport, blocks the crosslinking of mitochondrial membranes by the TZD probe. Knockdown of these proteins in Drosophila also led to increased hemolymph glucose and blocked drug action. In isolated brown adipose tissue (BAT cells, MSDC-0602, a PPARγ-sparing TZD, altered the incorporation of (13C-labeled carbon from glucose into acetyl CoA. These results identify Mpc1 and Mpc2 as components of the mitochondrial target of TZDs (mTOT and suggest that understanding the modulation of this complex, which appears to regulate pyruvate entry into the mitochondria, may provide a viable target for insulin sensitizing pharmacology.

  13. Hepatic Mitochondrial Pyruvate Carrier 1 Is Required for Efficient Regulation of Gluconeogenesis and Whole-Body Glucose Homeostasis.

    Science.gov (United States)

    Gray, Lawrence R; Sultana, Mst Rasheda; Rauckhorst, Adam J; Oonthonpan, Lalita; Tompkins, Sean C; Sharma, Arpit; Fu, Xiaorong; Miao, Ren; Pewa, Alvin D; Brown, Kathryn S; Lane, Erin E; Dohlman, Ashley; Zepeda-Orozco, Diana; Xie, Jianxin; Rutter, Jared; Norris, Andrew W; Cox, James E; Burgess, Shawn C; Potthoff, Matthew J; Taylor, Eric B

    2015-10-06

    Gluconeogenesis is critical for maintenance of euglycemia during fasting. Elevated gluconeogenesis during type 2 diabetes (T2D) contributes to chronic hyperglycemia. Pyruvate is a major gluconeogenic substrate and requires import into the mitochondrial matrix for channeling into gluconeogenesis. Here, we demonstrate that the mitochondrial pyruvate carrier (MPC) comprising the Mpc1 and Mpc2 proteins is required for efficient regulation of hepatic gluconeogenesis. Liver-specific deletion of Mpc1 abolished hepatic MPC activity and markedly decreased pyruvate-driven gluconeogenesis and TCA cycle flux. Loss of MPC activity induced adaptive utilization of glutamine and increased urea cycle activity. Diet-induced obesity increased hepatic MPC expression and activity. Constitutive Mpc1 deletion attenuated the development of hyperglycemia induced by a high-fat diet. Acute, virally mediated Mpc1 deletion after diet-induced obesity decreased hyperglycemia and improved glucose tolerance. We conclude that the MPC is required for efficient regulation of gluconeogenesis and that the MPC contributes to the elevated gluconeogenesis and hyperglycemia in T2D. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. MCT1 modulates cancer cell pyruvate export and growth of tumors that co-express MCT1 and MCT4

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    Hong, Candice Sun; Graham, Nicholas A.; Gu, Wen; Camacho, Carolina Espindola; Mah, Vei; Maresh, Erin L.; Alavi, Mohammed; Bagryanova, Lora; Krotee, Pascal A. L.; Gardner, Brian K.; Behbahan, Iman Saramipoor; Horvath, Steve; Chia, David; Mellinghoff, Ingo K.; Hurvitz, Sara A.; Dubinett, Steven M.; Critchlow, Susan E.; Kurdistani, Siavash K.; Goodglick, Lee; Braas, Daniel; Graeber, Thomas G.; Christofk, Heather R.

    2016-01-01

    SUMMARY Monocarboxylate Transporter 1 (MCT1) inhibition is thought to block tumor growth through disruption of lactate transport and glycolysis. Here we show MCT1 inhibition impairs proliferation of glycolytic breast cancer cells co-expressing MCT1 and MCT4 via disruption of pyruvate rather than lactate export. MCT1 expression is elevated in glycolytic breast tumors, and high MCT1 expression predicts poor prognosis in breast and lung cancer patients. Acute MCT1 inhibition reduces pyruvate export but does not consistently alter lactate transport or glycolytic flux in breast cancer cells that co-express MCT1 and MCT4. Despite the lack of glycolysis impairment, MCT1 loss-of-function decreases breast cancer cell proliferation and blocks growth of mammary fat pad xenograft tumors. Our data suggest MCT1 expression is elevated in glycolytic cancers to promote pyruvate export, which when inhibited enhances oxidative metabolism and reduces proliferation. This study presents an alternative molecular consequence of MCT1 inhibitors further supporting their use as anti-cancer therapeutics. PMID:26876179

  15. The E1 beta-subunit of pyruvate dehydrogenase is surface-expressed in Lactobacillus plantarum and binds fibronectin.

    Science.gov (United States)

    Vastano, Valeria; Salzillo, Marzia; Siciliano, Rosa A; Muscariello, Lidia; Sacco, Margherita; Marasco, Rosangela

    2014-01-01

    Lactobacillus plantarum is among the species with a probiotic activity. Adhesion of probiotic bacteria to host tissues is an important principle for strain selection, because it represents a crucial step in the colonization process of either pathogens or commensals. Most bacterial adhesins are proteins, and a major target for them is fibronectin, an extracellular matrix glycoprotein. In this study we demonstrate that PDHB, a component of the pyruvate dehydrogenase complex, is a factor contributing to fibronectin-binding in L. plantarum LM3. By means of fibronectin overlay immunoblotting assay, we identified a L. plantarum LM3 surface protein with apparent molecular mass of 35 kDa. Mass spectrometric analysis shows that this protein is the pyruvate dehydrogenase E1 beta-subunit (PDHB). The corresponding pdhB gene is located in a 4-gene cluster encoding pyruvate dehydrogenase. In LM3-B1, carrying a null mutation in pdhB, the 35 kDa adhesin was not anymore detectable by immunoblotting assay. Nevertheless, the pdhB null mutation did not abolish pdhA, pdhC, and pdhD transcription in LM3-B1. By adhesion assays, we show that LM3-B1 cells bind to immobilized fibronectin less efficiently than wild type cells. Moreover, we show that pdhB expression is negatively regulated by the CcpA protein and is induced by bile. Copyright © 2013. Published by Elsevier GmbH.

  16. A case of pyruvate dehydrogenase deficiency with low density areas in white matter noticed by CT scan

    International Nuclear Information System (INIS)

    Kimura, Akiko; Kyoya, Seizo; Matsushima, Akihiro; Irimichi, Hideki; Koike, Yoshiko.

    1985-01-01

    The patient was a 4-month-old boy, the first child of healthy, non-consanguineous patient. He was mildly asphyxiated at birth and developed severe convulsions at two days of age. At 4 months of age, he was referred to us because of infantile spasms and motor retardation. The EEG showed hypsarhythmia, ACTH and anticonvulsants were started, but his seizures were not controlled completely. At 8 months of age, the CT scan demonstrated a cerebral atrophy with enlarged ventricles and a diffuse low density of cerebral white matter, and lactic acidosis was first noticed. The glucose, glucagon, fructose, and alanine tolerance tests revealed almost normal responses in blood glucose levels and elevation of lactate levels above the initial value. Enzyme studies revealed a severe deficiency of pyruvate dehydrogenase complex and pyruvate dehydrogenase (E 1 ), and a normal activity of pyruvate carboxylase in liver obtained by biopsy. In biopsied muscle, mitochondria appeared normal. Treatment with thiamine, lipoic acid and anticonvulsants was not effective. The clinical picture of PDC deficiency has been correlated with the amount of the residual activity, and this case confirmed to the ''severe'' category. Several pathologic entities may be associated with PDHC deficiency, and CT findings in our case demonstrated the demyelinating condition. The precise relationship between the defect and the pathogenesis remains to be elucidated. (author)

  17. Improvement of ethanol yield from glycerol via conversion of pyruvate to ethanol in metabolically engineered Saccharomyces cerevisiae.

    Science.gov (United States)

    Yu, Kyung Ok; Jung, Ju; Ramzi, Ahmad Bazli; Kim, Seung Wook; Park, Chulhwan; Han, Sung Ok

    2012-02-01

    The conversion of low-priced glycerol to higher value products has been proposed as a way to improve the economic viability of the biofuels industry. In a previous study, the conversion of glycerol to ethanol in a metabolically engineered strain of Saccharomyces cerevisiae was accomplished by minimizing the synthesis of glycerol, the main by-product in ethanol fermentation processing. To further improve ethanol production, overexpression of the native genes involved in conversion of pyruvate to ethanol in S. cerevisiae was successfully accomplished. The overexpression of an alcohol dehydrogenase (adh1) and a pyruvate decarboxylase (pdc1) caused an increase in growth rate and glycerol consumption under fermentative conditions, which led to a slight increase of the final ethanol yield. The overall expression of the adh1 and pdc1 genes in the modified strains, combined with the lack of the fps1 and gpd2 genes, resulted in a 1.4-fold increase (about 5.4 g/L ethanol produced) in fps1Δgpd2Δ (pGcyaDak, pGupCas) (about 4.0 g/L ethanol produced). In summary, it is possible to improve the ethanol yield by overexpression of the genes involved in the conversion of pyruvate to ethanol in engineered S. cerevisiae using glycerol as substrate.

  18. Regulation of Muscle Pyruvate Dehydrogenase Complex in Insulin Resistance: Effects of Exercise and Dichloroacetate

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    Dumitru Constantin-Teodosiu

    2013-10-01

    Full Text Available Since the mitochondrial pyruvate dehydrogenase complex (PDC controls the rate of carbohydrate oxidation, impairment of PDC activity mediated by high-fat intake has been advocated as a causative factor for the skeletal muscle insulin resistance, metabolic syndrome, and the onset of type 2 diabetes (T2D. There are also situations where muscle insulin resistance can occur independently from high-fat dietary intake such as sepsis, inflammation, or drug administration though they all may share the same underlying mechanism, i.e., via activation of forkhead box family of transcription factors, and to a lower extent via peroxisome proliferator-activated receptors. The main feature of T2D is a chronic elevation in blood glucose levels. Chronic systemic hyperglycaemia is toxic and can lead to cellular dysfunction that may become irreversible over time due to deterioration of the pericyte cell's ability to provide vascular stability and control to endothelial proliferation. Therefore, it may not be surprising that T2D's complications are mainly macrovascular and microvascular related, i.e., neuropathy, retinopathy, nephropathy, coronary artery, and peripheral vascular diseases. However, life style intervention such as exercise, which is the most potent physiological activator of muscle PDC, along with pharmacological intervention such as administration of dichloroacetate or L-carnitine can prove to be viable strategies for treating muscle insulin resistance in obesity and T2D as they can potentially restore whole body glucose disposal.

  19. Role of plastidic pyruvate dehydrogenase complex (pl. PDC) in chloroplast metabolism of spinach

    International Nuclear Information System (INIS)

    Schulze-Siebert, D.; Homeyer, U.; Schultz, G.

    1986-01-01

    Labeling experiments of chloroplasts in the light ( 14 CO 2 , 2- 14 C-pyruvate etc.) revealed that pl. PDC is predominantly involved in the synthesis of branched chain amino acids and pl. isoprenoids (carotenes, PQ, α-T). In this context, pl. phosphoglycerate mutase as missing link in the C 3 → C 2 metabolism of chloroplasts was identified by latency experiments. This indicates a direct pathway from Calvin cycle to pl. PDC. Using protoplasts, maximal rates in pl. PDC metabolism were obtained. On the other hand, mitochondrial PDC in protoplasts is mainly involved in fatty acid synthesis by known mechanism. Additionally, cytosolic-ER-isoprenoids were formed (e.g. sterols). When 14 CO 2 was simultaneously applied with unlabeled acetate to protoplasts in the light an isotopic dilution of fatty acids were found but not of pl. isoprenoids. This may indicate an partially channeling of pl. PDC and mevalonate pathway for pl. isoprenoid synthesis. Inhibitory studies with DCMU point in the same direction

  20. An improved strategy for the crystallization of Leishmania mexicana pyruvate kinase

    International Nuclear Information System (INIS)

    Morgan, Hugh P.; McNae, Iain W.; Hsin, Kun-Yi; Michels, Paul A. M.; Fothergill-Gilmore, Linda A.; Walkinshaw, Malcolm D.

    2010-01-01

    The first crystal structure of Leishmania mexicana pyruvate kinase (LmPYK) obtained at a neutral pH. LmPYK was co-crystallized with the small molecule 1,3,6,8-pyrenetetrasulfonic acid, which provides a helpful intermolecular bridge between macromolecules. The inclusion of novel small molecules in crystallization experiments has provided very encouraging results and this method is now emerging as a promising alternative strategy for crystallizing ‘problematic’ biological macromolecules. These small molecules have the ability to promote lattice formation through stabilizing intermolecular interactions in protein crystals. Here, the use of 1,3,6,8-pyrenetetrasulfonic acid (PTS), which provides a helpful intermolecular bridge between Leishmania mexicana PYK (LmPYK) macromolecules in the crystal, is reported, resulting in the rapid formation of a more stable crystal lattice at neutral pH and greatly improved X-ray diffraction results. The refined structure of the LmPYK–PTS complex revealed the negatively charged PTS molecule to be stacked between positively charged (surface-exposed) arginine side chains from neighbouring LmPYK molecules in the crystal lattice

  1. A catalyzing phantom for reproducible dynamic conversion of hyperpolarized [1-¹³C]-pyruvate.

    Science.gov (United States)

    Walker, Christopher M; Lee, Jaehyuk; Ramirez, Marc S; Schellingerhout, Dawid; Millward, Steven; Bankson, James A

    2013-01-01

    In vivo real time spectroscopic imaging of hyperpolarized ¹³C labeled metabolites shows substantial promise for the assessment of physiological processes that were previously inaccessible. However, reliable and reproducible methods of measurement are necessary to maximize the effectiveness of imaging biomarkers that may one day guide personalized care for diseases such as cancer. Animal models of human disease serve as poor reference standards due to the complexity, heterogeneity, and transient nature of advancing disease. In this study, we describe the reproducible conversion of hyperpolarized [1-¹³C]-pyruvate to [1-¹³C]-lactate using a novel synthetic enzyme phantom system. The rate of reaction can be controlled and tuned to mimic normal or pathologic conditions of varying degree. Variations observed in the use of this phantom compare favorably against within-group variations observed in recent animal studies. This novel phantom system provides crucial capabilities as a reference standard for the optimization, comparison, and certification of quantitative imaging strategies for hyperpolarized tracers.

  2. A catalyzing phantom for reproducible dynamic conversion of hyperpolarized [1-¹³C]-pyruvate.

    Directory of Open Access Journals (Sweden)

    Christopher M Walker

    Full Text Available In vivo real time spectroscopic imaging of hyperpolarized ¹³C labeled metabolites shows substantial promise for the assessment of physiological processes that were previously inaccessible. However, reliable and reproducible methods of measurement are necessary to maximize the effectiveness of imaging biomarkers that may one day guide personalized care for diseases such as cancer. Animal models of human disease serve as poor reference standards due to the complexity, heterogeneity, and transient nature of advancing disease. In this study, we describe the reproducible conversion of hyperpolarized [1-¹³C]-pyruvate to [1-¹³C]-lactate using a novel synthetic enzyme phantom system. The rate of reaction can be controlled and tuned to mimic normal or pathologic conditions of varying degree. Variations observed in the use of this phantom compare favorably against within-group variations observed in recent animal studies. This novel phantom system provides crucial capabilities as a reference standard for the optimization, comparison, and certification of quantitative imaging strategies for hyperpolarized tracers.

  3. Metabolic modeling of energy balances in Mycoplasma hyopneumoniae shows that pyruvate addition increases growth rate.

    Science.gov (United States)

    Kamminga, Tjerko; Slagman, Simen-Jan; Bijlsma, Jetta J E; Martins Dos Santos, Vitor A P; Suarez-Diez, Maria; Schaap, Peter J

    2017-10-01

    Mycoplasma hyopneumoniae is cultured on large-scale to produce antigen for inactivated whole-cell vaccines against respiratory disease in pigs. However, the fastidious nutrient requirements of this minimal bacterium and the low growth rate make it challenging to reach sufficient biomass yield for antigen production. In this study, we sequenced the genome of M. hyopneumoniae strain 11 and constructed a high quality constraint-based genome-scale metabolic model of 284 chemical reactions and 298 metabolites. We validated the model with time-series data of duplicate fermentation cultures to aim for an integrated model describing the dynamic profiles measured in fermentations. The model predicted that 84% of cellular energy in a standard M. hyopneumoniae cultivation was used for non-growth associated maintenance and only 16% of cellular energy was used for growth and growth associated maintenance. Following a cycle of model-driven experimentation in dedicated fermentation experiments, we were able to increase the fraction of cellular energy used for growth through pyruvate addition to the medium. This increase in turn led to an increase in growth rate and a 2.3 times increase in the total biomass concentration reached after 3-4 days of fermentation, enhancing the productivity of the overall process. The model presented provides a solid basis to understand and further improve M. hyopneumoniae fermentation processes. Biotechnol. Bioeng. 2017;114: 2339-2347. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  4. Role of isoenzyme M2 of pyruvate kinase in urothelial tumorigenesis.

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    Zhou, Haiping; Wang, Xing; Mo, Lan; Liu, Yan; He, Feng; Zhang, Fenglin; Huang, Kuo-How; Wu, Xue-Ru

    2016-04-26

    The conversion of precancerous lesions to full-fledged cancers requires the affected cells to surpass certain rate-limiting steps. We recently showed that activation of HRAS proto-oncogene in urothelial cells of transgenic mice causes simple urothelial hyperplasia (SUH) which is persistent and whose transition to low-grade papillary urothelial carcinoma (UC) must undergo nodular urothelial hyperplasia (NUH). We hypothesized that NUH, which has acquired fibrovascular cores, plays critical roles in mesenchymal-to-epithelial signaling, breaching the barriers of urothelial tumor initiation. Using proteomics involving two-dimensional gel electrophoresis, immunoblotting with pan-phosphotyrosine antibody and MALDI-mass spectrometry, we identified isoform 2 of pyruvate kinase (PKM2) as the major tyrosine-phosphorylated protein switched on during NUH. We extended this finding using specimens from transgenic mice, human UC and UC cell lines, establishing that PKM2, but not its spliced variant PKM1, was over-expressed in low-grade and, more prominently, high-grade UC. In muscle-invasive UC, PKM2 was co-localized with cytokeratins 5 and 14, UC progenitor markers. Specific inhibition of PKM2 by siRNA or shRNA suppressed UC cell proliferation via increased apoptosis, autophagy and unfolded protein response. These results strongly suggest that PKM2 plays an important role in the genesis of low-grade non-invasive and high-grade invasive urothelial carcinomas.

  5. Pyruvate dehydrogenase subunit β of Lactobacillus plantarum is a collagen adhesin involved in biofilm formation.

    Science.gov (United States)

    Salzillo, Marzia; Vastano, Valeria; Capri, Ugo; Muscariello, Lidia; Marasco, Rosangela

    2017-04-01

    Multi-functional surface proteins have been observed in a variety of pathogenic bacteria, where they mediate host cell adhesion and invasion, as well as in commensal bacterial species, were they mediate positive interaction with the host. Among these proteins, some glycolytic enzymes, expressed on the bacterial cell surface, can bind human extracellular matrix components (ECM). A major target for them is collagen, an abundant glycoprotein of connective tissues. We have previously shown that the enolase EnoA1 of Lactobacillus plantarum, one of the most predominant species in the gut microbiota of healthy individuals, is involved in binding with collagen type I (CnI). In this study, we found that PDHB, a component of the pyruvate dehydrogenase complex, contributes to the L. plantarum LM3 adhesion to CnI. By a cellular adhesion assay to immobilized CnI, we show that LM3-B1 cells, carrying a null mutation in the pdhB gene, bind to CnI - coated surfaces less efficiently than wild-type cells. Moreover, we show that the PDHB-CnI interaction requires a native state for PDHB. We also analyzed the ability to develop biofilm in wild-type and mutant strains and we found that the lack of the PDHB on cell surface generates cells partially impaired in biofilm development. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Integrative proteomics and biochemical analyses define Ptc6p as the Saccharomyces cerevisiae pyruvate dehydrogenase phosphatase.

    Science.gov (United States)

    Guo, Xiao; Niemi, Natalie M; Coon, Joshua J; Pagliarini, David J

    2017-07-14

    The pyruvate dehydrogenase complex (PDC) is the primary metabolic checkpoint connecting glycolysis and mitochondrial oxidative phosphorylation and is important for maintaining cellular and organismal glucose homeostasis. Phosphorylation of the PDC E1 subunit was identified as a key inhibitory modification in bovine tissue ∼50 years ago, and this regulatory process is now known to be conserved throughout evolution. Although Saccharomyces cerevisiae is a pervasive model organism for investigating cellular metabolism and its regulation by signaling processes, the phosphatase(s) responsible for activating the PDC in S. cerevisiae has not been conclusively defined. Here, using comparative mitochondrial phosphoproteomics, analyses of protein-protein interactions by affinity enrichment-mass spectrometry, and in vitro biochemistry, we define Ptc6p as the primary PDC phosphatase in S. cerevisiae Our analyses further suggest additional substrates for related S. cerevisiae phosphatases and describe the overall phosphoproteomic changes that accompany mitochondrial respiratory dysfunction. In summary, our quantitative proteomics and biochemical analyses have identified Ptc6p as the primary-and likely sole- S. cerevisiae PDC phosphatase, closing a key knowledge gap about the regulation of yeast mitochondrial metabolism. Our findings highlight the power of integrative omics and biochemical analyses for annotating the functions of poorly characterized signaling proteins. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  7. Posttranslational Modifications of Pyruvate Kinase M2: Tweaks that Benefit Cancer

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    Gopinath Prakasam

    2018-02-01

    Full Text Available Cancer cells rewire metabolism to meet biosynthetic and energetic demands. The characteristic increase in glycolysis, i.e., Warburg effect, now considered as a hallmark, supports cancer in various ways. To attain such metabolic reshuffle, cancer cells preferentially re-express the M2 isoform of pyruvate kinase (PKM2, M2-PK and alter its quaternary structure to generate less-active PKM2 dimers. The relatively inactive dimers cause the accumulation of glycolytic intermediates that are redirected into anabolic pathways. In addition, dimeric PKM2 also benefits cancer cells through various non-glycolytic moonlight functions, such as gene transcription, protein kinase activity, and redox balance. A large body of data have shown that several distinct posttranslation modifications (PTMs regulate PKM2 in a way that benefits cancer growth, e.g., formation of PKM2 dimers. This review discusses the recent advancements in our understanding of various PTMs and the benefits they impart to the sustenance of cancer. Understanding the PTMs in PKM2 is crucial to assess their therapeutic potential and to design novel anticancer strategies.

  8. Mitochondrial pyruvate carrier function determines cell stemness and metabolic reprogramming in cancer cells

    Science.gov (United States)

    Li, Xiaoran; Kan, Quancheng; Fan, Zhirui; Li, Yaqing; Ji, Yasai; Zhao, Jing; Zhang, Mingzhi; Grigalavicius, Mantas; Berge, Viktor; Goscinski, Mariusz Adam; M. Nesland, Jahn; Suo, Zhenhe

    2017-01-01

    One of the remarkable features of cancer cells is aerobic glycolysis, a phenomenon known as the “Warburg Effect”, in which cells rely preferentially on glycolysis instead of oxidative phosphorylation (OXPHOS) as the main energy source even in the presence of high oxygen tension. Cells with dysfunctional mitochondria are unable to generate sufficient ATP from mitochondrial OXPHOS, and then are forced to rely on glycolysis for ATP generation. Here we report our results in a prostate cancer cell line in which the mitochondrial pyruvate carrier 1 (MPC1) gene was knockout. It was discovered that the MPC1 gene knockout cells revealed a metabolism reprogramming to aerobic glycolysis with reduced ATP production, and the cells became more migratory and resistant to both chemotherapy and radiotherapy. In addition, the MPC1 knockout cells expressed significantly higher levels of the stemness markers Nanog, Hif1α, Notch1, CD44 and ALDH. To further verify the correlation of MPC gene function and cell stemness/metabolic reprogramming, MPC inhibitor UK5099 was applied in two ovarian cancer cell lines and similar results were obtained. Taken together, our results reveal that functional MPC may determine the fate of metabolic program and the stemness status of cancer cells in vitro. PMID:28624784

  9. Crystallization and preliminary X-ray analysis of pyruvate kinase from Bacillus stearothermophilus

    International Nuclear Information System (INIS)

    Suzuki, Kenichiro; Ito, Sohei; Shimizu-Ibuka, Akiko; Sakai, Hiroshi

    2005-01-01

    This report describes the crystallization and X-ray diffraction data collection of three types (wild-type, W416F/V435W and C9S/C268S) of B. stearothermophilus. Crystals of C9S/C268S belonged to space group P6 2 22 and diffracted to a resolution of 2.4 Å. Pyruvate kinase (PK) from a moderate thermophile, Bacillus stearothermophilus (BstPK), is an allosteric enzyme activated by AMP and ribose 5-phosphate but not by fructose 1,6-bisphosphate (FBP). However, almost all other PKs are activated by FBP. The wild-type and W416F/V435W mutant BstPKs were crystallized by the hanging-drop vapour-diffusion method. However, they were unsuitable for structural analysis because their data sets exhibited low completeness. A crystal suitable for structural analysis was obtained using C9S/C268S enzyme. The crystal belonged to space group P6 2 22, with unit-cell parameters a = b = 145.97, c = 118.03 Å

  10. Inhibition effects of furfural on alcohol dehydrogenase, aldehyde dehydrogenase and pyruvate dehydrogenase.

    Science.gov (United States)

    Modig, Tobias; Lidén, Gunnar; Taherzadeh, Mohammad J

    2002-01-01

    The kinetics of furfural inhibition of the enzymes alcohol dehydrogenase (ADH; EC 1.1.1.1), aldehyde dehydrogenase (AlDH; EC 1.2.1.5) and the pyruvate dehydrogenase (PDH) complex were studied in vitro. At a concentration of less than 2 mM furfural was found to decrease the activity of both PDH and AlDH by more than 90%, whereas the ADH activity decreased by less than 20% at the same concentration. Furfural inhibition of ADH and AlDH activities could be described well by a competitive inhibition model, whereas the inhibition of PDH was best described as non-competitive. The estimated K(m) value of AlDH for furfural was found to be about 5 microM, which was lower than that for acetaldehyde (10 microM). For ADH, however, the estimated K(m) value for furfural (1.2 mM) was higher than that for acetaldehyde (0.4 mM). The inhibition of the three enzymes by 5-hydroxymethylfurfural (HMF) was also measured. The inhibition caused by HMF of ADH was very similar to that caused by furfural. However, HMF did not inhibit either AlDH or PDH as severely as furfural. The inhibition effects on the three enzymes could well explain previously reported in vivo effects caused by furfural and HMF on the overall metabolism of Saccharomyces cerevisiae, suggesting a critical role of these enzymes in the observed inhibition. PMID:11964178

  11. Ameliorative effect of ethyl pyruvate in neuropathic pain induced by chronic constriction injury of sciatic nerve

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    Varsha J. Bansode

    2014-01-01

    Full Text Available Objective: The present study was designed to investigate the ameliorative effects of ethyl pyruvate (EP in chronic constriction injury (CCI-induced painful neuropathy in rats. Materials and Methods: EP 50 and 100 mg/kg was administered for 21 consecutive days starting from the day of surgery. The effects of EP in the paw pressure, acetone drop, and tail heat immersion tests were assessed, reflecting the degree of mechanical hyperalgesia, cold allodynia, and spinal thermal sensation, respectively. Axonal degeneration of the sciatic nerve was assessed histopathologically. The levels of thiobarbituric acid reactive species, reduced glutathione (GSH, catalase (CAT, and superoxide dismutase (SOD were determined to assess oxidative stress. Key Findings: Administration of 50 and 100 mg/kg EP attenuated the reduction of nociceptive threshold in the paw pressure, acetone drop, and tail heat immersion tests. EP 100 mg/kg significantly attenuated reactive changes in histopathology and increase in oxidative stress. Conclusion: EP 100 mg/kg showed beneficial activity against nerve trauma-induced neuropathy. Hence, it can be used as a better treatment option in neuropathic pain (NP. The observed antinociceptive effects of EP may possibly be attributed to its antioxidant and anti-inflammatory activity.

  12. Influence of 120 kDa Pyruvate:Ferredoxin Oxidoreductase on Pathogenicity of Trichomonas vaginalis.

    Science.gov (United States)

    Song, Hyun-Ouk

    2016-02-01

    Trichomonas vaginalis is a flagellate protozoan parasite and commonly infected the lower genital tract in women and men. Iron is a known nutrient for growth of various pathogens, and also reported to be involved in establishment of trichomoniasis. However, the exact mechanism was not clarified. In this study, the author investigated whether the 120 kDa protein of T. vaginalis may be involved in pathogenicity of trichomonads. Antibodies against 120 kDa protein of T. vaginalis, which was identified as pyruvate:ferredoxin oxidoreductase (PFOR) by peptide analysis of MALDI-TOF-MS, were prepared in rabbits. Pretreatment of T. vaginalis with anti-120 kDa Ab decreased the proliferation and adherence to vaginal epithelial cells (MS74) of T. vaginalis. Subcutaneous tissue abscess in anti-120 kDa Ab-treated T. vaginalis-injected mice was smaller in size than that of untreated T. vaginalis-infected mice. Collectively, the 120 kDa protein expressed by iron may be involved in proliferation, adhesion to host cells, and abscess formation, thereby may influence on the pathogenicity of T. vaginalis.

  13. Control of biotin biosynthesis in mycobacteria by a pyruvate carboxylase dependent metabolic signal.

    Science.gov (United States)

    Lazar, Nathaniel; Fay, Allison; Nandakumar, Madhumitha; Boyle, Kerry E; Xavier, Joao; Rhee, Kyu; Glickman, Michael S

    2017-12-01

    Biotin is an essential cofactor utilized by all domains of life, but only synthesized by bacteria, fungi and plants, making biotin biosynthesis a target for antimicrobial development. To understand biotin biosynthesis in mycobacteria, we executed a genetic screen in Mycobacterium smegmatis for biotin auxotrophs and identified pyruvate carboxylase (Pyc) as required for biotin biosynthesis. The biotin auxotrophy of the pyc::tn strain is due to failure to transcriptionally induce late stage biotin biosynthetic genes in low biotin conditions. Loss of bioQ, the repressor of biotin biosynthesis, in the pyc::tn strain reverted biotin auxotrophy, as did reconstituting the last step of the pathway through heterologous expression of BioB and provision of its substrate DTB. The role of Pyc in biotin regulation required its catalytic activities and could be supported by M. tuberculosis Pyc. Quantitation of the kinetics of depletion of biotinylated proteins after biotin withdrawal revealed that Pyc is the most rapidly depleted biotinylated protein and metabolomics revealed a broad metabolic shift in wild type cells upon biotin withdrawal which was blunted in cell lacking Pyc. Our data indicate that mycobacterial cells monitor biotin sufficiency through a metabolic signal generated by dysfunction of a biotinylated protein of central metabolism. © 2017 John Wiley & Sons Ltd.

  14. Functional Characterization of Waterlogging and Heat Stresses Tolerance Gene Pyruvate decarboxylase 2 from Actinidia deliciosa

    Directory of Open Access Journals (Sweden)

    Hui-Ting Luo

    2017-11-01

    Full Text Available A previous report showed that both Pyruvate decarboxylase (PDC genes were significantly upregulated in kiwifruit after waterlogging treatment using Illumina sequencing technology, and that the kiwifruit AdPDC1 gene was required during waterlogging, but might not be required during other environmental stresses. Here, the function of another PDC gene, named AdPDC2, was analyzed. The expression of the AdPDC2 gene was determined using qRT-PCR, and the results showed that the expression levels of AdPDC2 in the reproductive organs were much higher than those in the nutritive organs. Waterlogging, NaCl, and heat could induce the expression of AdPDC2. Overexpression of kiwifruit AdPDC2 in transgenic Arabidopsis enhanced resistance to waterlogging and heat stresses in five-week-old seedlings, but could not enhance resistance to NaCl and mannitol stresses at the seed germination stage and in early seedlings. These results suggested that the kiwifruit AdPDC2 gene may play an important role in waterlogging resistance and heat stresses in kiwifruit.

  15. Acute hypertensive stress imaged by cardiac hyperpolarized [1-C]pyruvate magnetic resonance

    DEFF Research Database (Denmark)

    Tougaard, Rasmus Stilling; Hansen, Esben Søvsø Szocska; Laustsen, Christoffer

    2018-01-01

    PURPOSE: Deranged metabolism is now recognized as a key causal factor in a variety of heart diseases, and is being studied extensively. However, invasive methods may alter metabolism, and conventional imaging techniques measure tracer uptake but not downstream metabolism. These challenges may...... be overcome by hyperpolarized MR, a noninvasive technique currently crossing the threshold into human trials. The aim of this study was to image metabolic changes in the heart in response to endogastric glucose bolus and to acute hypertension. METHODS: Five postprandial pigs were scanned with hyperpolarized.......008) and ejection fraction decreased from 54 ± 2% to 47 ± 6% (P = 0.03) The hemodynamic changes were accompanied by increases in the hyperpolarized [1-13C]pyruvate MR derived ratios of lactate/alanine (from 0.58 ± 0.13 to 0.78 ± 0.06, P = 0.03) and bicarbonate/alanine (from 0.55 ± 0.12 to 0.91 ± 0.14, P = 0...

  16. SH2 domain-containing phosphatase 1 regulates pyruvate kinase M2 in hepatocellular carcinoma.

    Science.gov (United States)

    Tai, Wei-Tien; Hung, Man-Hsin; Chu, Pei-Yi; Chen, Yao-Li; Chen, Li-Ju; Tsai, Ming-Hsien; Chen, Min-Husan; Shiau, Chung-Wai; Boo, Yin-Pin; Chen, Kuen-Feng

    2016-04-19

    Pyruvate kinase M2 (PKM2) is known to promote tumourigenesis through dimer formation of p-PKM2Y105. Here, we investigated whether SH2-containing protein tyrosine phosphatase 1 (SHP-1) decreases p-PKM2Y105 expression and, thus, determines the sensitivity of sorafenib through inhibiting the nuclear-related function of PKM2. Immunoprecipitation and immunoblot confirmed the effect of SHP-1 on PKM2Y105 dephosphorylation. Lactate production was assayed in cells and tumor samples to determine whether sorafenib reversed the Warburg effect. Clinical hepatocellular carcinoma (HCC) tumor samples were assessed for PKM2 expression. SHP-1 directly dephosphorylated PKM2 at Y105 and further decreased the proliferative activity of PKM2; similar effects were found in sorafenib-treated HCC cells. PKM2 was also found to determine the sensitivity of targeted drugs, such as sorafenib, brivanib, and sunitinib, by SHP-1 activation. Significant sphere-forming activity was found in HCC cells stably expressing PKM2. Clinical findings suggest that PKM2 acts as a predicting factor of early recurrence in patients with HCC, particularly those without known risk factors (63.6%). SHP-1 dephosphorylates PKM2 at Y105 to inhibit nuclear function of PKM2 and determines the efficacy of targeted drugs. Targeting PKM2 by SHP-1 might provide new therapeutic insights for patients with HCC.

  17. Expression, purification, crystallization and preliminary X-ray diffraction analysis of dihydrodipicolinate synthase from Bacillus anthracis in the presence of pyruvate

    International Nuclear Information System (INIS)

    Voss, Jarrod E.; Scally, Stephen W.; Taylor, Nicole L.; Dogovski, Con; Alderton, Malcolm R.; Hutton, Craig A.; Gerrard, Juliet A.; Parker, Michael W.; Dobson, Renwick C. J.; Perugini, Matthew A.

    2009-01-01

    Dihydrodipicolinate synthase (DHDPS) catalyses an important step in lysine biosynthesis. Here, the expression, purification, crystallization and preliminary diffraction analysis to 2.15 Å resolution of DHDPS from B. anthracis soaked with the substrate pyruvate are reported. Dihydrodipicolinate synthase (DHDPS) catalyses the first committed step in the lysine-biosynthesis pathway in bacteria, plants and some fungi. In this study, the expression of DHDPS from Bacillus anthracis (Ba-DHDPS) and the purification of the recombinant enzyme in the absence and presence of the substrate pyruvate are described. It is shown that DHDPS from B. anthracis purified in the presence of pyruvate yields greater amounts of recombinant enzyme with more than 20-fold greater specific activity compared with the enzyme purified in the absence of substrate. It was therefore sought to crystallize Ba-DHDPS in the presence of the substrate. Pyruvate was soaked into crystals of Ba-DHDPS prepared in 0.2 M sodium fluoride, 20%(w/v) PEG 3350 and 0.1 M bis-tris propane pH 8.0. Preliminary X-ray diffraction data of the recombinant enzyme soaked with pyruvate at a resolution of 2.15 Å are presented. The pending crystal structure of the pyruvate-bound form of Ba-DHDPS will provide insight into the function and stability of this essential bacterial enzyme

  18. 143 - 148_Makeri et al.

    African Journals Online (AJOL)

    USER

    2015-06-01

    Jun 1, 2015 ... Yuan et al., 2003), antimicrobial activity (Sundarrao et al., 1993; Betancur-Galvis et al., 1999; Takashi et al., 2006), anti-parasitic, anti-malarial activities (Alali et al., 1998; Jaramillo et al., 2000; Luna et al.,. 2005). This study evaluates the antibacterial activity of extract of stem –bark and leaf extracts of Annona.

  19. Monstres et murailles, Alexandre et bicornu, mythes et bon sens

    Directory of Open Access Journals (Sweden)

    Jean-Louis Bacqué-Grammont

    2009-05-01

    Full Text Available Parmi les mythes récurrents à travers les lieux et les âges, celui du bâtisseur de murailles défendant une humanité civilisée contre l'Autre, sous ses aspects les plus effrayants, a connu une durable fortune depuis le prototype d'un Alexandre le Grand légendaire jusqu'à des avatars composites, bien vivaces dans nombre de littératures islamiques.En trois points différents de cet inépuisable domaine de recherche, chacun des auteurs a procédé à un sondage sommaire. Il en ressort maint exemple de continuités, de parallélismes et de confluences complexes, mais aussi les premiers signes d'érosion des mythes sous l'effet d'un esprit critique attisé par le vent d'Occident.

  20. The application of isotopic (32P and 15N) dilution techniques to evaluate the interactive effect of phosphate-solubilizing rhizobacteria, mycorrhizal fungi and Rhizobium to improve the agronomic efficiency of rock phosphate for legume crops

    International Nuclear Information System (INIS)

    Barea, J.M.; Toro, M.; Azcon, R.; Orozco, M.O.; Campos, E.; Azcon, R.

    2002-01-01

    A pot experiment was designed to evaluate the interactive effects of multifunctional microbial inoculation treatments and rock phosphate (RP) application on N and P uptake by alfalfa through the use of 15 N and 32 P isotopic dilution approaches. The microbial inocula consisted of a wild type (WT) Rhizobium meliloti strain, the arbuscular mycorrhizal (AM) fungus Glomus mosseae (Nicol. and Gerd.) Gerd. and Trappe, and a phosphate solubilizing rhizobacterium (Enterobacter sp.). Inoculated microorganisms were established in the root tissues and/or in the rhizosphere soil of alfalfa plants (Medicago sativa L.). Improvements in N and P accumulation in alfalfa corroborate beneficial effects of Rhizobium and AM interactions. Inoculation with selected rhizobacteria improved the AM effect on N or P accumulation in both the RP-added soil and in the non RP-amended controls. Measurements of the 15 N/ 14 N ratio in plant shoots indicate an enhancement of the N 2 fixation rates in Rhizobium-inoculated AM-plants, over that achieved by Rhizobium in non-mycorrhizal plants. Whether or not RP was added, AM-inoculated plants showed a lower specific activity ( 32 P/ 31 P) than did their comparable non-mycorrhizal controls, suggesting that the plant was using otherwise unavailable P sources. The phosphate-solubilizing, AM-associated, microbiota could in fact release phosphate ions, either from the added RP or from the indigenous 'less-available' soil phosphate. A low Ca concentrations in the test soil may have benefited P solubilization. Under field conditions, the inoculation with AM fungi significantly increased plant biomass and N and P accumulation in plant tissues. Phosphate-solubilizing rhizobacteria improved mycorrhizal responses in soil dually receiving RP and organic matter amendments. Organic matter addition favoured RP solubilization. This, together with a tailored microbial inoculation, increased the agronomic efficiency of RP in the test soil that was Ca deficient at neutral

  1. The application of isotopic ({sup 32}P and {sup 15}N) dilution techniques to evaluate the interactive effect of phosphate-solubilizing rhizobacteria, mycorrhizal fungi and Rhizobium to improve the agronomic efficiency of rock phosphate for legume crops

    Energy Technology Data Exchange (ETDEWEB)

    Barea, J.M. [Departamento de Microbiologia del Suelo y Sistemas Simbioticos (Spain)]. E-mail: jmbarea@eez.csic.es; Toro, M.; Azcon, R. [Departamento de Microbiologia del Suelo y Sistemas Simbioticos (Spain); Orozco, M.O. [Instituto de Sistematica y Ecologia, Academia Cubana de Ciencias, Habana (Cuba); Campos, E. [Departamento de Ciencias de la Tierra y Quimica Ambiental Estacion Experimental del Zaidin (CSIC), Granada (Spain); Azcon, R. [Departamento de Microbiologia del Suelo y Sistemas Simbioticos (Spain)

    2002-05-15

    A pot experiment was designed to evaluate the interactive effects of multifunctional microbial inoculation treatments and rock phosphate (RP) application on N and P uptake by alfalfa through the use of {sup 15}N and {sup 32}P isotopic dilution approaches. The microbial inocula consisted of a wild type (WT) Rhizobium meliloti strain, the arbuscular mycorrhizal (AM) fungus Glomus mosseae (Nicol. and Gerd.) Gerd. and Trappe, and a phosphate solubilizing rhizobacterium (Enterobacter sp.). Inoculated microorganisms were established in the root tissues and/or in the rhizosphere soil of alfalfa plants (Medicago sativa L.). Improvements in N and P accumulation in alfalfa corroborate beneficial effects of Rhizobium and AM interactions. Inoculation with selected rhizobacteria improved the AM effect on N or P accumulation in both the RP-added soil and in the non RP-amended controls. Measurements of the {sup 15}N/{sup 14}N ratio in plant shoots indicate an enhancement of the N{sub 2} fixation rates in Rhizobium-inoculated AM-plants, over that achieved by Rhizobium in non-mycorrhizal plants. Whether or not RP was added, AM-inoculated plants showed a lower specific activity ({sup 32}P/{sup 31}P) than did their comparable non-mycorrhizal controls, suggesting that the plant was using otherwise unavailable P sources. The phosphate-solubilizing, AM-associated, microbiota could in fact release phosphate ions, either from the added RP or from the indigenous 'less-available' soil phosphate. A low Ca concentrations in the test soil may have benefited P solubilization. Under field conditions, the inoculation with AM fungi significantly increased plant biomass and N and P accumulation in plant tissues. Phosphate-solubilizing rhizobacteria improved mycorrhizal responses in soil dually receiving RP and organic matter amendments. Organic matter addition favoured RP solubilization. This, together with a tailored microbial inoculation, increased the agronomic efficiency of RP in the

  2. MICROFINANCE ET PAUVRETÉ

    International Development Research Centre (IDRC) Digital Library (Canada)

    AIDER LES DÉMUNIS À S'AIDER EUX-MÊMES. Le CRDI et ses partenaires félicitent chaudement le professeur Muhammad. Yunus et la Grameen Bank, lauréats conjoints du prix Nobel de la paix 2006. Nous applaudissons cet hommage rendu à notre partenaire dans la lutte contre la pauvreté et sommes ravis, par ...

  3. Mouvements et enjeux sociaux

    International Development Research Centre (IDRC) Digital Library (Canada)

    20 févr. 2004 ... les théories sociologiques et politiques en rapport avec les perceptions, le ...... Enfin, le recrutement de force des shégués dans l'armé et la police n'a pas fait mieux ..... dépassent en ingéniosité et en stratégie. D'où le vœu ...

  4. Femmes, genre et violence

    OpenAIRE

    Castan-Vicente, Florys; Benevent, Laurie

    2016-01-01

    Le présent article s’attache à comparer deux ouvrages sur la violence et les femmes, parus à quinze ans d’intervalle : De la violence et des femmes (1997) et Penser la violence des femmes (2012). Il s’agira de dégager de cette comparaison des conclusions sur l’évolution, entre ces deux dates, de ce champ d’étude, très neuf lors de la parution du premier ouvrage, et ayant connu un développement important par la suite.

  5. Reve et action: Bloch, Heidegger et Levinas

    Czech Academy of Sciences Publication Activity Database

    Bierhanzl, Jan

    2016-01-01

    Roč. 12, č. 3 (2016), s. 1-6 ISSN 1336-6556 R&D Projects: GA ČR(CZ) GA16-23046S Institutional support: RVO:67985955 Keywords : possibility * wishing * decision * action * dream * utopia Subject RIV: AA - Philosophy ; Religion http://www.ostium.sk/sk/r%C8%87ve-er-action-bloch-heidegger-et-levinas/

  6. Attenuation of Methotrexate-Induced Embryotoxicity and Oxidative Stress by Ethyl Pyruvate

    Directory of Open Access Journals (Sweden)

    Najafi Gholamreza

    2016-07-01

    Full Text Available Background Methotrexate (MTX, as an anti-folate agent, is widely used in the treatment of rheumatic disorders and malignant tumors, however it damages reproductive sys- tem in mice. The aim of this research was to study the effects of ethyl pyruvate (EP on embryo development and oxidative stress changes in the testis of mice treated with MTX. Materials and Methods In this experimental study, thirty-two adult male Naval Medical Research Institute mice, with average weight of 26 ± 2 g, were divided into four groups. The first group (control received distilled water (0.1 ml/mice/day, while the second group was intraperitoneally (IP treated with 20 mg/kg MTX once per week. The third group was IP treated with 40 mg/kg/day EP, and the fourth group was IP treated with both 20 mg/kg MTX and 40 mg/kg/day EP for 30 days. At the end of treatment fertilization rate and embryonic development were evaluated. Differences between these groups were assessed by ANOVA using the SPSS software package for Windows with a Tukey-Kramer multiple post-hoc comparison test. Results MTX treatment caused significant (P<0.05 increase in malondialdehyde (MDA and reduced catalase (CAT, as well as leading to in vitro fertilization (IVF and embryonic development. The improved effects of EP on the IVF were determined by the reduced level of MDA (index of oxidative stress and significant increased level of CAT (a key antioxidant. We observed significant increase in fertilization rate and embryonic development in the treated group with both MTX and EP. Conclusion It is suggested that EP can be useful in ameliorating testicular damages and embryotoxicity induced by MTX. These effects could be attributed to its antioxidant properties.

  7. miR-122 targets pyruvate kinase M2 and affects metabolism of hepatocellular carcinoma.

    Directory of Open Access Journals (Sweden)

    Angela M Liu

    Full Text Available In contrast to normal differentiated cells that depend on mitochondrial oxidative phosphorylation for energy production, cancer cells have evolved to utilize aerobic glycolysis (Warburg's effect, with benefit of providing intermediates for biomass production. MicroRNA-122 (miR-122 is highly expressed in normal liver tissue regulating a wide variety of biological processes including cellular metabolism, but is reduced in hepatocellular carcinoma (HCC. Overexpression of miR-122 was shown to inhibit cancer cell proliferation, metastasis, and increase chemosensitivity, but its functions in cancer metabolism remains unknown. The present study aims to identify the miR-122 targeted genes and to investigate the associated regulatory mechanisms in HCC metabolism. We found the ectopic overexpression of miR-122 affected metabolic activities of HCC cells, evidenced by the reduced lactate production and increased oxygen consumption. Integrated gene expression analysis in a cohort of 94 HCC tissues revealed miR-122 level tightly associated with a battery of glycolytic genes, in which pyruvate kinase (PK gene showed the strongest anti-correlation coefficient (Pearson r = -0.6938, p = <0.0001. In addition, reduced PK level was significantly associated with poor clinical outcomes of HCC patients. We found isoform M2 (PKM2 is the dominant form highly expressed in HCC and is a direct target of miR-122, as overexpression of miR-122 reduced both the mRNA and protein levels of PKM2, whereas PKM2 re-expression abrogated the miR-122-mediated glycolytic activities. The present study demonstrated the regulatory role of miR-122 on PKM2 in HCC, having an implication of therapeutic intervention targeting cancer metabolic pathways.

  8. An allostatic mechanism for M2 pyruvate kinase as an amino-acid sensor.

    Science.gov (United States)

    Yuan, Meng; McNae, Iain W; Chen, Yiyuan; Blackburn, Elizabeth A; Wear, Martin A; Michels, Paul A M; Fothergill-Gilmore, Linda A; Hupp, Ted; Walkinshaw, Malcolm D

    2018-05-10

    We have tested the effect of all 20 proteinogenic amino acids on the activity of the M2 isoenzyme of pyruvate kinase (M2PYK) and show that within physiologically relevant concentrations, phenylalanine, alanine, tryptophan, methionine, valine, and proline act as inhibitors while histidine and serine act as activators. Size exclusion chromatography has been used to show that all amino acids, whether activators or inhibitors, stabilise the tetrameric form of M2PYK. In the absence of amino-acid ligands an apparent tetramer-monomer dissociation K d is estimated to be ~0.9 µM with a slow dissociation rate (t 1/2 ~ 15 min). X-ray structures of M2PYK complexes with alanine, phenylalanine, and tryptophan show the M2PYK locked in an inactive T-state conformation, while activators lock the M2PYK tetramer in the active R-state conformation. Amino-acid binding in the allosteric pocket triggers rigid body rotations (11°) stabilising either T or R-states. The opposing inhibitory and activating effects of the non-essential amino acids serine and alanine suggest that M2PYK could act as a rapid-response nutrient sensor to rebalance cellular metabolism. This competition at a single allosteric site between activators and inhibitors provides a novel regulatory mechanism by which M2PYK activity is finely tuned by the relative (but not absolute) concentrations of activator and inhibitor amino acids. Such 'allostatic' regulation may be important in metabolic reprogramming and influencing cell fate. ©2018 The Author(s).

  9. The effect of ethyl pyruvate on oxidative stress in intestine and bacterial translocation after thermal injury.

    Science.gov (United States)

    Karabeyoğlu, Melih; Unal, Bülent; Bozkurt, Betül; Dolapçi, Iştar; Bilgihan, Ayşe; Karabeyoğlu, Işil; Cengiz, Omer

    2008-01-01

    Thermal injury causes a breakdown in the intestinal mucosal barrier due to ischemia reperfusion injury, which can induce bacterial translocation (BT), sepsis, and multiple organ failure in burn patients. The aim of this study was to investigate the effect of ethyl pyruvate (EP) on intestinal oxidant damage and BT in burn injury. Thirty-two rats were randomly divided into four groups. The sham group was exposed to 21 degrees C water and injected intraperitoneal with saline (1 mL/100 g). The sham + EP group received EP (40 mg/kg) intraperitoneally 6 h after the sham procedure. The burn group was exposed to thermal injury and given intraperitoneal saline injection (1 mL/100 g). The burn + EP group received EP (40 mg/kg) intraperitoneally 6 h after thermal injury. Twenty-four hours later, tissue samples were obtained from mesenteric lymph nodes, spleen, and liver for microbiological analysis and ileum samples were harvested for biochemical analysis. Thermal injury caused severe BT in burn group. EP supplementation decreased BT in mesenteric lymph nodes and spleen in the burn + EP group compared with the burn group (P < 0.05). Also, burn caused BT in liver, but this finding was not statistically significant among all groups. Thermal injury caused a statistically significant increase in malondialdehyde and myeloperoxidase levels, and EP prevented this effects in the burn + EP group compared with the burn group (P < 0.05). Our data suggested that EP can inhibit the BT and myeloperoxidase and malondialdehyde production in intestine following thermal injury, suggesting anti-inflammatory and anti-oxidant properties of EP.

  10. Physical exercise reduces pyruvate carboxylase (PCB) and contributes to hyperglycemia reduction in obese mice.

    Science.gov (United States)

    Muñoz, Vitor Rosetto; Gaspar, Rafael Calais; Crisol, Barbara Moreira; Formigari, Guilherme Pedron; Sant'Ana, Marcella Ramos; Botezelli, José Diego; Gaspar, Rodrigo Stellzer; da Silva, Adelino S R; Cintra, Dennys Esper; de Moura, Leandro Pereira; Ropelle, Eduardo Rochete; Pauli, José Rodrigo

    2018-07-01

    The present study evaluated the effects of exercise training on pyruvate carboxylase protein (PCB) levels in hepatic tissue and glucose homeostasis control in obese mice. Swiss mice were distributed into three groups: control mice (CTL), fed a standard rodent chow; diet-induced obesity (DIO), fed an obesity-inducing diet; and a third group, which also received an obesity-inducing diet, but was subjected to an exercise training protocol (DIO + EXE). Protocol training was carried out for 1 h/d, 5 d/wk, for 8 weeks, performed at an intensity of 60% of exhaustion velocity. An insulin tolerance test (ITT) was performed in the last experimental week. Twenty-four hours after the last physical exercise session, the animals were euthanized and the liver was harvested for molecular analysis. Firstly, DIO mice showed increased epididymal fat and serum glucose and these results were accompanied by increased PCB and decreased p-Akt in hepatic tissue. On the other hand, physical exercise was able to increase the performance of the mice and attenuate PCB levels and hyperglycemia in DIO + EXE mice. The above findings show that physical exercise seems to be able to regulate hyperglycemia in obese mice, suggesting the participation of PCB, which was enhanced in the obese condition and attenuated after a treadmill running protocol. This is the first study to be aimed at the role of exercise training in hepatic PCB levels, which may be a novel mechanism that can collaborate to reduce the development of hyperglycemia and type 2 diabetes in DIO mice.

  11. Characterization of the distal promoter of the human pyruvate carboxylase gene in pancreatic beta cells.

    Directory of Open Access Journals (Sweden)

    Ansaya Thonpho

    Full Text Available Pyruvate carboxylase (PC is an enzyme that plays a crucial role in many biosynthetic pathways in various tissues including glucose-stimulated insulin secretion. In the present study, we identify promoter usage of the human PC gene in pancreatic beta cells. The data show that in the human, two alternative promoters, proximal and distal, are responsible for the production of multiple mRNA isoforms as in the rat and mouse. RT-PCR analysis performed with cDNA prepared from human liver and islets showed that the distal promoter, but not the proximal promoter, of the human PC gene is active in pancreatic beta cells. A 1108 bp fragment of the human PC distal promoter was cloned and analyzed. It contains no TATA box but possesses two CCAAT boxes, and other putative transcription factor binding sites, similar to those of the distal promoter of rat PC gene. To localize the positive regulatory region in the human PC distal promoter, 5'-truncated and the 25-bp and 15-bp internal deletion mutants of the human PC distal promoter were generated and used in transient transfections in INS-1 832/13 insulinoma and HEK293T (kidney cell lines. The results indicated that positions -340 to -315 of the human PC distal promoter serve as (an activator element(s for cell-specific transcription factor, while the CCAAT box at -71/-67, a binding site for nuclear factor Y (NF-Y, as well as a GC box at -54/-39 of the human PC distal promoter act as activator sequences for basal transcription.

  12. Cultures et organisations

    NARCIS (Netherlands)

    Hofstede, G.; Hofstede, G.J.; Minkov, M.

    2010-01-01

    La coopération interculturelle, une question de survie Véritable atlas des valeurs culturelles, paru en 18 langues, Cultures et organisations est le fruit de plus de 40 ans de recherches menées dans plus de 100 pays. Il est aujourd'hui le livre de référence des chercheurs, universitaires et

  13. Jeux et enjeux olympiques

    Directory of Open Access Journals (Sweden)

    Pierre LEBLANC

    1989-06-01

    Full Text Available Les actes de candidatures et de choix des villes pour l'organisation des différentes sessions des Jeux Olympiques contemporains ne sont pas le fruit du hasard. Dans l'un et l'autre cas, il s'agit d'actes dont la signification s'inscrit dans le contexte politique du moment.

  14. Ojo et al (2)

    African Journals Online (AJOL)

    DELL

    network geometry hence control how the samples' ... generate different permeability curves from wire- ... occupy in the reservoir pore system (McPhee et. ..... Fig.3. Poroperm cross-plot for a homogenous reservoir. Ojo et al.: Rock Type Based ...

  15. Et dansk hotell

    DEFF Research Database (Denmark)

    Baca, Susan; Busck, Ole Gunni

    Rapporten præsenterer resultatet af en undersøgelse af, hvorledes et hotel i Nordjylland fungerer som arbejdsplads for indvandrere af overvejende ikke-vestlig oprindelse. Der fokuseres på i hvilket omfang og gennem hvilke mekanismer arbejdsmiljjøet i bred forstand, herunder forhold i ledelsen...

  16. Interactions et formalisations intersubjectives

    OpenAIRE

    Bouvet, Rose-Marie

    2008-01-01

    L'ingénierie, modélisation nécessaire et leurranteDéfinir l'ingénierieL'ingénierie de formation est née d'une volonté de rationaliser des coûts et des pratiques de formation. A cette logique d'efficacité impulsée par les commanditaires et financeurs, (du secteur privé comme du secteur public), notamment depuis la mise en place de la formation professionnelle continue et des politiques d'insertion et réinsertion professionnelle, s'est développée la mise en cause d'un modèle d'enseignement axé ...

  17. Cartographie et intelligence artificielle

    Directory of Open Access Journals (Sweden)

    Denise Pumain

    2005-11-01

    Full Text Available Le monde complexe dans lequel nous évoluons est aussi paradoxal : ainsi, que peut-on prédire quant à la diffusion du savoir faire des géographes en termes de cartographie et de visualisation de l’information géographique ? On voit surgir toujours plus d’instruments et d’occasions de se repérer et d’admirer des images de la terre, mais il n’est pas sûr que cela fasse progresser dans le public la connaissance des cartes et de leur interprétation. Prenons l’exemple du repérage, par GPS, et bient...

  18. Produção de mudas de acácia colonizadas com micorrizas e rizóbio em diferentes recipientes Production of acacia plants colonized with mycorrhizas and rhizobium in different recipients

    Directory of Open Access Journals (Sweden)

    Jolimar Antonio Schiavo

    2003-02-01

    Full Text Available Realizou-se um experimento em casa de vegetação, com o objetivo de avaliar diferentes métodos na produção de mudas de Acacia mangium Willd, colonizadas com fungos micorrízicos arbusculares (FMAs e rizóbio. O delineamento experimental foi o inteiramente casualizado num esquema fatorial 4x2 (controle, FMAs, rizóbio e FMAs + rizóbio x blocos prensados e tubetes de plástico, com seis repetições. Os blocos prensados foram confeccionados com substratos orgânicos (bagaço de cana + torta de filtro de usina açucareira e vermiculita, colocados em fôrma metálica de 60x40x20 cm e prensados a 10 kgf cm-2, a fim de proporcionar agregação do material. A inoculação do rizóbio foi realizada com estirpe selecionada para a espécie (Br 3609, Br 6009. A inoculação de FMAs foi feita no momento da confecção dos blocos. Mudas de Acacia mangium que receberam inóculo de FMAs + rizóbio e produzidas em blocos prensados apresentaram maior produção de matéria seca e conteúdo de N na parte aérea. O conteúdo de P na parte aérea é significativamente maior somente nas mudas infectadas com os FMAs, independentemente do tipo de recipiente.A greenhouse experiment was carried out in order to evaluate different methods to produce Acacia mangium Willd plant seedlings, inoculated with arbuscular mycorrhizal fungi (AMF and rhizobium. A completely randomized design in a factorial scheme 4x2 (control, AMF, rhizobium and AMF + rhizobium x pressed blocks and plastic tubes, with six repetitions was used. The pressed blocks used to produce Acacia mangium plants were made with organic residue from sugarcane (sugarcane bagasse + filter cake and vermiculite. The inoculation with rhizobium was done with selected strain (Br 3609, Br 6009. The inoculation with AMF was done at the time when pressed blocks were made. Acacia mangium plants inoculated with both AMF + rhizobium led to a significant increase in dry matter yield and N content of shoot plants, only in

  19. Selecting in vitro of Rhizobiumfor tolerance to acidity and aluminium Selección in vitro de Rhizobium tolerante a acidez y aluminio

    Directory of Open Access Journals (Sweden)

    Campos Segura Ricardo

    1995-12-01

    Full Text Available Fifty strains of Rhizobium tropiciisolated of Sabana de Bogotá soils and foreigns collections were screened for tolerance of acidity and aluminium in liquid and sol id culture. Assesment of visible turbidity and colonies growth, respectively, indicated five
    (5 strains tolerant of pH 4.5 and pH 5.0 and 10 or 20 u M Aluminium. Strains that tolerated the 10 west pH values in culture were tolerant of the highest aluminium concentrations
    The cultural test should be used to predict the ability of Rhizobium to growth and for use as inoculants in low pH area.La apertura económica puso de presente la obligación de revisar las formas de producción de los cultivos comerciales, Con el fin de competir adecuadamente en mercados internacionales. Actualmente, leguminosas, como el frijol (Phaseolus vulgarís se presentan, actualmente, como cultivo alternativo para reemplazar cultivos tradicionales en la Sabana de Bogotá. Existe un alto porcentaje de suelos ácidos en Colombia, así como problemas nutricionales, en los cuales la deficiencia de nitrógeno es muy común. El presente trabajo se realizó con el objetivo de seleccionar "in vitro" cepas de Rizobium tropici tolerantes a acidez y aluminio, en medios de cultivo diferentes. Inicialmente se hizo una preselección "in vitro" de cepas tolerantes a tres niveles de pH 4,0; 4,5 y 5,0, utilizando el medio líquido de Wood y Cooper y usando 50 cepas entre nativas y foráneas. En este caso, se seleccionaron las cepas RC 92, RC 117, C 7, C 11, C 14, C 53, Nifta1182, RC 70, RC 85, CIAT 899, CIAT 144 y Niftal 241. Posteriormente, se realizó una selección "in vitro" de cepas tolerantes a dos niveles de pH: 4,5 y 5,0 y a
    cuatro niveles de aluminio: 0,5; 10 y 20 M, utilizando dos fuentes de aluminio: AlCl3 y ALK(S042 y empleando dos medios de cultivo: el líquido de Wood y Cooper y el sólido de Keyser y Munns. Las cepas RC 85, C 11, CIAT 899, CIAT 144 y Niftal 182, fueron seleccionadas como las de

  20. GABAergic transmission and chloride equilibrium potential are not modulated by pyruvate in the developing optic tectum of Xenopus laevis tadpoles.

    Directory of Open Access Journals (Sweden)

    Arseny S Khakhalin

    Full Text Available In the developing mammalian brain, gamma-aminobutyric acid (GABA is thought to play an excitatory rather than an inhibitory role due to high levels of intracellular Cl(- in immature neurons. This idea, however, has been questioned by recent studies which suggest that glucose-based artificial cerebrospinal fluid (ACSF may be inadequate for experiments on immature and developing brains. These studies suggest that immature neurons may require alternative energy sources, such as lactate or pyruvate. Lack of these other energy sources is thought to result in artificially high intracellular Cl(- concentrations, and therefore a more depolarized GABA receptor (GABAR reversal potential. Since glucose metabolism can vary widely among different species, it is important to test the effects of these alternative energy sources on different experimental preparations. We tested whether pyruvate affects GABAergic transmission in isolated brains of developing wild type Xenopus tadpoles in vitro by recording the responsiveness of tectal neurons to optic nerve stimulation, and by measuring currents evoked by local GABA application in a gramicidin perforated patch configuration. We found that, in contrast with previously reported results, the reversal potential for GABAR-mediated currents does not change significantly between developmental stages 45 and 49. Partial substitution of glucose by pyruvate had only minor effects on both the GABA reversal potential, and the responsiveness of tectal neurons at stages 45 and 49. Total depletion of energy sources from the ACSF did not affect neural responsiveness. We also report a strong spatial gradient in GABA reversal potential, with immature cells adjacent to the lateral and caudal proliferative zones having more positive reversal potentials. We conclude that in this experimental preparation standard glucose-based ACSF is an appropriate extracellular media for in vitro experiments.

  1. Exploration of swapping enzymatic function between two proteins: A simulation study of chorismate mutase and isochorismate pyruvate lyase

    Science.gov (United States)

    Choutko, Alexandra; Eichenberger, Andreas P; Gunsteren, Wilfred F; Dolenc, Jožica

    2013-01-01

    The enzyme chorismate mutase EcCM from Escherichia coli catalyzes one of the few pericyclic reactions in biology, the transformation of chorismate to prephenate. The isochorismate pyruvate lyase PchB from Pseudomonas aeroginosa catalyzes another pericyclic reaction, the isochorismate to salicylate transformation. Interestingly, PchB possesses weak chorismate mutase activity as well thus being able to catalyze two distinct pericyclic reactions in a single active site. EcCM and PchB possess very similar folds, despite their low sequence identity. Using molecular dynamics simulations of four combinations of the two enzymes (EcCM and PchB) with the two substrates (chorismate and isochorismate) we show that the electrostatic field due to EcCM at atoms of chorismate favors the chorismate to prephenate transition and that, analogously, the electrostatic field due to PchB at atoms of isochorismate favors the isochorismate to salicylate transition. The largest differences between EcCM and PchB in electrostatic field strengths at atoms of the substrates are found to be due to residue side chains at distances between 0.6 and 0.8 nm from particular substrate atoms. Both enzymes tend to bring their non-native substrate in the same conformation as their native substrate. EcCM and to a lower extent PchB fail in influencing the forces on and conformations of the substrate such as to favor the other chemical reaction (isochorismate pyruvate lyase activity for EcCM and chorismate mutase activity for PchB). These observations might explain the difficulty of engineering isochorismate pyruvate lyase activity in EcCM by solely mutating active site residues. PMID:23595942

  2. Exploration of swapping enzymatic function between two proteins: a simulation study of chorismate mutase and isochorismate pyruvate lyase.

    Science.gov (United States)

    Choutko, Alexandra; Eichenberger, Andreas P; van Gunsteren, Wilfred F; Dolenc, Jožica

    2013-06-01

    The enzyme chorismate mutase EcCM from Escherichia coli catalyzes one of the few pericyclic reactions in biology, the transformation of chorismate to prephenate. The isochorismate pyruvate lyase PchB from Pseudomonas aeroginosa catalyzes another pericyclic reaction, the isochorismate to salicylate transformation. Interestingly, PchB possesses weak chorismate mutase activity as well thus being able to catalyze two distinct pericyclic reactions in a single active site. EcCM and PchB possess very similar folds, despite their low sequence identity. Using molecular dynamics simulations of four combinations of the two enzymes (EcCM and PchB) with the two substrates (chorismate and isochorismate) we show that the electrostatic field due to EcCM at atoms of chorismate favors the chorismate to prephenate transition and that, analogously, the electrostatic field due to PchB at atoms of isochorismate favors the isochorismate to salicylate transition. The largest differences between EcCM and PchB in electrostatic field strengths at atoms of the substrates are found to be due to residue side chains at distances between 0.6 and 0.8 nm from particular substrate atoms. Both enzymes tend to bring their non-native substrate in the same conformation as their native substrate. EcCM and to a lower extent PchB fail in influencing the forces on and conformations of the substrate such as to favor the other chemical reaction (isochorismate pyruvate lyase activity for EcCM and chorismate mutase activity for PchB). These observations might explain the difficulty of engineering isochorismate pyruvate lyase activity in EcCM by solely mutating active site residues. © 2013 The Protein Society.

  3. Pyruvate dehydrogenase complexes from the equine nematode, Parascaris equorum, and the canine cestode, Dipylidium caninum, helminths exhibiting anaerobic mitochondrial metabolism.

    Science.gov (United States)

    Diaz, F; Komuniecki, R W

    1994-10-01

    The pyruvate dehydrogenase complex (PDC) has been purified to apparent homogeneity from 2 parasitic helminths exhibiting anaerobic mitochondrial metabolism, the equine nematode, Parascaris equorum, and the canine cestode, Dipylidium caninum. The P. equorum PDC yielded 7 major bands when separated by SDS-PAGE. The bands of 72, 55-53.5, 41 and 36 kDa corresponded to E2, E3, E1 alpha and E1 beta, respectively. The complex also contained additional unidentified proteins of 43 and 45 kDa. Incubation of the complex with [2-14C]pyruvate resulted in the acetylation of only E2. These results suggest that the P. equorum PDC lacks protein X and exhibits an altered subunit composition, as has been described previously for the PDC of the related nematode, Ascaris suum. In contrast, the D. caninum PDC yielded only four major bands after SDS-PAGE of 59, 58, 39 and 34 kDa, which corresponded to E3, E2, E1 alpha and E1 beta, respectively. Incubation of the D. caninum complex with [2-14C]pyruvate resulted in the acetylation of E2 and a second protein which comigrated with E3, suggesting that the D. caninum complex contained protein X and had a subunit composition similar to PDCs from other eukaryotic organisms. Both helminth complexes appeared less sensitive to inhibition by elevated NADH/NAD+ ratios than complexes isolated from aerobic organisms, as would be predicted for PDCs from organisms exploiting microaerobic habitats. These results suggest that although these helminths have similar anaerobic mitochondrial pathways, they contain significantly different PDCs.

  4. Effects of hypoxia and pyruvate infusion on myocardial fatty acid oxidation measured with 123I heptadecanoic acid

    International Nuclear Information System (INIS)

    Comans, E.F.I.; Visser, F.C.; Elzinga, Gijs

    1993-01-01

    Radio-iodinated fatty acids like 123 I heptadecanoic acid (HDA) can be used for the non-invasive delineation of myocardial non-esterified fatty acid (FA) metabolism. In this study the quantitative value of HDA was assessed for the measurement of myocardial FA oxidation. In an isolated saline perfused rat heart preparation myocardial time-activity curves were made during control perfusion and after inhibition of FA oxidation by hypoxia and infusion of 10.0 mM pyruvate, respectively. Control experiments were performed using 1- 14 C palmitate as the 'golden standard' for myocardial FA oxidation. Myocardial HDA oxidation was calculated from the amplitude of the third exponential term of the time-activity curve. During control perfusion no differences were observed between the calculated oxygen equivalents (from HDA oxidation) and the measured (A-V oxygen content difference) and the estimated ( 14 CO 2 production) values. Inhibition of palmitate oxidation with pyruvate was accurately detected with HDA. During hypoxic perfusion, an overestimation of palmitate oxidation was calculated on the basic of HDA oxidation. Infusion of pyruvate did not influence the time constants of the time-activity curves, whereas during hypoxic perfusion an increase of the time constant of the third exponential term was observed, probably caused by the presence of back-diffusion of non-metabolized HDA. We conclude that HDA can be used as a quantitative tool for the measurement of myocardial FA oxidation under various metabolic conditions. During periods of a decreased oxygen availability back-diffusion of FA needs to be taken into account for the interpretation of the myocardial time-activity curves. (author)

  5. Gluconeogenesis is associated with high rates of tricarboxylic acid and pyruvate cycling in fasting northern elephant seals.

    Science.gov (United States)

    Champagne, Cory D; Houser, Dorian S; Fowler, Melinda A; Costa, Daniel P; Crocker, Daniel E

    2012-08-01

    Animals that endure prolonged periods of food deprivation preserve vital organ function by sparing protein from catabolism. Much of this protein sparing is achieved by reducing metabolic rate and suppressing gluconeogenesis while fasting. Northern elephant seals (Mirounga angustirostris) endure prolonged fasts of up to 3 mo at multiple life stages. During these fasts, elephant seals maintain high levels of activity and energy expenditure associated with breeding, reproduction, lactation, and development while maintaining rates of glucose production typical of a postabsorptive mammal. Therefore, we investigated how fasting elephant seals meet the requirements of glucose-dependent tissues while suppressing protein catabolism by measuring the contribution of glycogenolysis, glycerol, and phosphoenolpyruvate (PEP) to endogenous glucose production (EGP) during their natural 2-mo postweaning fast. Additionally, pathway flux rates associated with the tricarboxylic acid (TCA) cycle were measured specifically, flux through phosphoenolpyruvate carboxykinase (PEPCK) and pyruvate cycling. The rate of glucose production decreased during the fast (F(1,13) = 5.7, P = 0.04) but remained similar to that of postabsorptive mammals. The fractional contributions of glycogen, glycerol, and PEP did not change with fasting; PEP was the primary gluconeogenic precursor and accounted for ∼95% of EGP. This large contribution of PEP to glucose production occurred without substantial protein loss. Fluxes through the TCA cycle, PEPCK, and pyruvate cycling were higher than reported in other species and were the most energetically costly component of hepatic carbohydrate metabolism. The active pyruvate recycling fluxes detected in elephant seals may serve to rectify gluconeogeneic PEP production during restricted anaplerotic inflow in these fasting-adapted animals.

  6. Quantification of in vivo metabolic kinetics of hyperpolarized pyruvate in rat kidneys using dynamic 13C MRSI.

    Science.gov (United States)

    Xu, Tao; Mayer, Dirk; Gu, Meng; Yen, Yi-Fen; Josan, Sonal; Tropp, James; Pfefferbaum, Adolf; Hurd, Ralph; Spielman, Daniel

    2011-10-01

    With signal-to-noise ratio enhancements on the order of 10,000-fold, hyperpolarized MRSI of metabolically active substrates allows the study of both the injected substrate and downstream metabolic products in vivo. Although hyperpolarized [1-(13)C]pyruvate, in particular, has been used to demonstrate metabolic activities in various animal models, robust quantification and metabolic modeling remain important areas of investigation. Enzyme saturation effects are routinely seen with commonly used doses of hyperpolarized [1-(13)C]pyruvate; however, most metrics proposed to date, including metabolite ratios, time-to-peak of metabolic products and single exchange rate constants, fail to capture these saturation effects. In addition, the widely used small-flip-angle excitation approach does not correctly model the inflow of fresh downstream metabolites generated proximal to the target slice, which is often a significant factor in vivo. In this work, we developed an efficient quantification framework employing a spiral-based dynamic spectroscopic imaging approach. The approach overcomes the aforementioned limitations and demonstrates that the in vivo (13)C labeling of lactate and alanine after a bolus injection of [1-(13)C]pyruvate is well approximated by saturatable kinetics, which can be mathematically modeled using a Michaelis-Menten-like formulation, with the resulting estimated apparent maximal reaction velocity V(max) and apparent Michaelis constant K(M) being unbiased with respect to critical experimental parameters, including the substrate dose, bolus shape and duration. Although the proposed saturatable model has a similar mathematical formulation to the original Michaelis-Menten kinetics, it is conceptually different. In this study, we focus on the (13)C labeling of lactate and alanine and do not differentiate the labeling mechanism (net flux or isotopic exchange) or the respective contribution of various factors (organ perfusion rate, substrate transport

  7. The pkI gene encoding pyruvate kinase I links to the luxZ gene which enhances bioluminescence of the lux operon from Photobacterium leiognathi.

    Science.gov (United States)

    Lin, J W; Lu, H C; Chen, H Y; Weng, S F

    1997-10-09

    Partial 3'-end nucleotide sequence of the pkI gene (GenBank accession No. AF019143) from Photobacterium leiognathi ATCC 25521 has been determined, and the encoded pyruvate kinase I is deduced. Pyruvate kinase I is the key enzyme of glycolysis, which converts phosphoenol pyruvate to pyruvate. Alignment and comparison of pyruvate kinase Is from P. leiognathi, E. coli and Salmonella typhimurium show that they are homologous. Nucleotide sequence reveals that the pkI gene is linked to the luxZ gene that enhances bioluminescence of the lux operon from P. leiognathi. The gene order of the pkI and luxZ genes is-pk1-ter-->-R&R"-luxZ-ter"-->, whereas ter is transcriptional terminator for the pkI and related genes, and R&R" is the regulatory region and ter" is transcriptional terminator for the luxZ gene. It clearly elicits that the pkI gene and luxZ gene are divided to two operons. Functional analysis confirms that the potential hairpin loop omega T is the transcriptional terminator for the pkI and related genes. It infers that the pkI and related genes are simply linked to the luxZ gene in P. leiognathi genome.

  8. A Comparison between Radiolabeled Fluorodeoxyglucose Uptake and Hyperpolarized 13C-Labeled Pyruvate Utilization as Methods for Detecting Tumor Response to Treatment

    Directory of Open Access Journals (Sweden)

    Timothy H. Witney

    2009-06-01

    Full Text Available Detection of early tumor responses to treatment can give an indication of clinical outcome. Positron emission tomography measurements of the uptake of the glucose analog, [18F] 2-fluoro-2-deoxy-d-glucose (FDG, have demonstrated their potential for detecting early treatment response in the clinic. We have shown recently that 13C magnetic resonance spectroscopy and spectroscopic imaging measurements of the uptake and conversion of hyperpolarized [1-13C]pyruvate into [1-13C]lactate can be used to detect treatment response in a murine lymphoma model. The present study compares these magnetic resonance measurements with changes in FDG uptake after chemotherapy. A decrease in FDG uptake was found to precede the decrease in flux of hyperpolarized 13C label between pyruvate and lactate, both in tumor cells in vitro and in tumors in vivo. However, the magnitude of the decrease in FDG uptake and the decrease in pyruvate to lactate flux was comparable at 24 hours after drug treatment. In cells, the decrease in FDG uptake was shown to correlate with changes in plasma membrane expression of the facilitative glucose transporters, whereas the decrease in pyruvate to lactate flux could be explained by an increase in poly(ADP-ribose polymerase activity and subsequent depletion of the NAD(H pool. These results show that measurement of flux between pyruvate and lactate may be an alternative to FDG-positron emission tomography for imaging tumor treatment response in the clinic.

  9. The progression from a lower to a higher invasive stage of bladder cancer is associated with severe alterations in glucose and pyruvate metabolism

    Energy Technology Data Exchange (ETDEWEB)

    Conde, Vanessa R. [CICS-UBI–Health Sciences Research Centre, University of Beira Interior, Covilhã (Portugal); Oliveira, Pedro F. [CICS-UBI–Health Sciences Research Centre, University of Beira Interior, Covilhã (Portugal); Department of Microscopy, Laboratory of Cell Biology and Unit for Multidisciplinary Research in Biomedicine, Abel Salazar Institute of Biomedical Sciences, University of Porto – UMIB/ICBAS/UP (Portugal); Nunes, Ana R.; Rocha, Cátia S. [CICS-UBI–Health Sciences Research Centre, University of Beira Interior, Covilhã (Portugal); Ramalhosa, Elsa; Pereira, José A. [Mountain Research Centre (CIMO), School of Agriculture, Polytechnic Institute of Bragança (Portugal); Alves, Marco G., E-mail: alvesmarc@gmail.com [CICS-UBI–Health Sciences Research Centre, University of Beira Interior, Covilhã (Portugal); Silva, Branca M., E-mail: bmcms@ubi.pt [CICS-UBI–Health Sciences Research Centre, University of Beira Interior, Covilhã (Portugal)

    2015-07-01

    Cancer cells present a particular metabolic behavior. We hypothesized that the progression of bladder cancer could be accompanied by changes in cells glycolytic profile. We studied two human bladder cancer cells, RT4 and TCCSUP, in which the latter represents a more invasive stage. The levels of glucose, pyruvate, alanine and lactate in the extracellular media were measured by Proton Nuclear Magnetic Resonance. The protein expression levels of glucose transporters 1 (GLUT1) and 3 (GLUT3), monocarboxylate transporter 4 (MCT4), phosphofructokinase-1 (PFK1), glutamic-pyruvate transaminase (GPT) and lactate dehydrogenase (LDH) were determined. Our data showed that glucose consumption and GLUT3 levels were similar in both cell lines, but TCCSUP cells displayed lower levels of GLUT1 and PFK expression. An increase in pyruvate consumption, concordant with the higher levels of lactate and alanine production, was also detected in TCCSUP cells. Moreover, TCCSUP cells presented lower protein expression levels of GPT and LDH. These results illustrate that bladder cancer progression is associated with alterations in cells glycolytic profile, namely the switch from glucose to pyruvate consumption in the more aggressive stage. This may be useful to develop new therapies and to identify biomarkers for cancer progression. - Highlights: • Metabolic phenotype of less and high invasive bladder cancer cells was studied. • Bladder cancer progression involves alterations in cells glycolytic profile. • More invasive bladder cancer cells switch from glucose to pyruvate consumption. • Our results may help to identify metabolic biomarkers of bladder cancer progression.

  10. Growth of Campylobacter incubated aerobically in fumarate-pyruvate media or media supplemented with dairy, meat, or soy extracts and peptones.

    Science.gov (United States)

    Hinton, Arthur

    2016-09-01

    The ability of Campylobacter to grow aerobically in media supplemented with fumarate-pyruvate or with dairy, meat, or soy extracts or peptones was examined. Optical densities (OD) of Campylobacter cultured in basal media, media supplemented with fumarate-pyruvate or with 1.0, 2.5, 5.0, or 7.5% beef extract was measured. Growth was also compared in media supplemented with other extracts or peptones. Finally, cfu/mL of Campylobacter recovered from basal media or media supplemented with fumarate-pyruvate, casamino acids, beef extract, soytone, or beef extract and soytone was determined. Results indicated that OD of cultures grown in media supplemented with fumarate-pyruvate or with 5.0 or 7.5% beef extract were higher than OD of isolates grown in basal media or media supplemented with lower concentrations of beef extract. Highest OD were produced by isolates grown in media supplemented with beef extract, peptone from meat, polypeptone, proteose peptone, or soytone. Also, more cfu/mL were recovered from media with fumarate-pyruvate, beef extract, soytone, or beef extract-soytone than from basal media or media with casamino acids. Findings indicate that media supplemented with organic acids, vitamins, and minerals and media supplemented with extracts or peptones containing these metabolites can support aerobic growth of Campylobacter. Published by Elsevier Ltd.

  11. Metabolic fate of glucose in rats with traumatic brain injury and pyruvate or glucose treatments: A NMR spectroscopy study.

    Science.gov (United States)

    Shijo, Katsunori; Sutton, Richard L; Ghavim, Sima S; Harris, Neil G; Bartnik-Olson, Brenda L

    2017-01-01

    Administration of sodium pyruvate (SP; 9.08 μmol/kg, i.p.), ethyl pyruvate (EP; 0.34 μmol/kg, i.p.) or glucose (GLC; 11.1 μmol/kg, i.p.) to rats after unilateral controlled cortical impact (CCI) injury has been reported to reduce neuronal loss and improve cerebral metabolism. In the present study these doses of each fuel or 8% saline (SAL; 5.47 nmoles/kg) were administered immediately and at 1, 3, 6 and 23 h post-CCI. At 24 h all CCI groups and non-treated Sham injury controls were infused with [1,2 13 C] glucose for 68 min 13 C nuclear magnetic resonance (NMR) spectra were obtained from cortex + hippocampus tissues from left (injured) and right (contralateral) hemispheres. All three fuels increased lactate labeling to a similar degree in the injured hemisphere. The amount of lactate labeled via the pentose phosphate and pyruvate recycling (PPP + PR) pathway increased in CCI-SAL and was not improved by SP, EP, and GLC treatments. Oxidative metabolism, as assessed by glutamate labeling, was reduced in CCI-SAL animals. The greatest improvement in oxidative metabolism was observed in animals treated with SP and fewer improvements after EP or GLC treatments. Compared to SAL, all three fuels restored glutamate and glutamine labeling via pyruvate carboxylase (PC), suggesting improved astrocyte metabolism following fuel treatment. Only SP treatments restored the amount of [4 13 C] glutamate labeled by the PPP + PR pathway to sham levels. Milder injury effects in the contralateral hemisphere appear normalized by either SP or EP treatments, as increases in the total pool of 13 C lactate and labeling of lactate in glycolysis, or decreases in the ratio of PC/PDH labeling of glutamine, were found only for CCI-SAL and CCI-GLC groups compared to Sham. The doses of SP, EP and GLC examined in this study all enhanced lactate labeling and restored astrocyte-specific PC activity but differentially affected neuronal metabolism after CCI injury. The restoration of

  12. Structure of the oxalate-ATP complex with pyruvate kinase: ATP as a bridging ligand for the two divalent cations

    International Nuclear Information System (INIS)

    Lodato, D.T.; Reed, G.H.

    1987-01-01

    The 2 equiv of divalent cation that are required cofactors for pyruvate kinase reside in sites of different affinities for different species of cation. The intrinsic selectivity of the protein-based site for Mn(II) and of the nucleotide-based site for Mg(II) has been exploited in electron paramagnetic resonance (EOR) investigations of ligands for Mn(II) at the protein-based site. Oxalate, a structural analogue of the enolate of pyruvate, has been used as a surrogate for the reactive form of pyruvate in complexes with enzyme, Mn(II), Mg(II), and ATP. Superhyperfine coupling between the unpaired electron spin of Mn(II) and the nuclear spin of 17 O, specifically incorporated into oxalate, shows that oxalate is bound at the active site as a bidentate chelate with Mn(II). Coordination of the γ-phosphate of ATP to this same Mn(II) center is revealed by observation of superhyperfine coupling from 17 O regiospecifically incorporated into the γ-phosphate group of ATP. By contrast, 17 O in the α-phosphate or in the β-phosphate groups of ATP does not influence the spectrum. Experiments in 17 O-enriched water show that there is also a single water ligand bound to the Mn(II). These data indicate that ATP bridges Mn(II) and Mg(II) at the active site. A close spacing of the two divalent cations is also evident from the occurrence of magnetic interactions for complexes in which 2 equiv of Mn(II) are present at the active site. The structure for the enzyme-Mn(II)-oxalate-Mg(II)-ATP complex suggests a scheme for the normal reverse reaction of pyruvate kinase in which the divalent cation at the protein-based site activates the keto acid substrate through chelation and promotes phospho transfer by simultaneous coordination to the enolate oxygen and to a pendant oxygen from the γ-phosphate of ATP

  13. Neonatal pyruvate dehydrogenase deficiency due to a R302H mutation in the PDHA1 gene: MRI findings

    International Nuclear Information System (INIS)

    Soares-Fernandes, Joao P.; Ribeiro, Manuel; Magalhaes, Zita; Rocha, Jaime F.; Teixeira-Gomes, Roseli; Cruz, Romeu; Leijser, Lara M.

    2008-01-01

    Pyruvate dehydrogenase (PDH) deficiency is one of the most common causes of congenital lactic acidosis. Correlations between the genetic defect and neuroimaging findings are lacking. We present conventional and diffusion-weighted MRI findings in a 7-day-old male neonate with PDH deficiency due to a mosaicism for the R302H mutation in the PDHA1 gene. Corpus callosum dysgenesis, widespread increased diffusion in the white matter, and bilateral subependymal cysts were the main features. Although confirmation of PDH deficiency depends on specialized biochemical analyses, neonatal MRI plays a role in evaluating the pattern and extent of brain damage, and potentially in early diagnosis and clinical decision making. (orig.)

  14. Coupling between the blood lactate-to-pyruvate ratio and MCA Vmean at the onset of exercise in humans

    DEFF Research Database (Denmark)

    Rasmussen, Peter; Madsen, Camilla A; Nielsen, Henning B

    2009-01-01

    Activation-induced increase in cerebral blood flow is coupled to enhanced metabolic activity, maybe with brain tissue redox state and oxygen tension as key modulators. To evaluate this hypothesis at the onset of exercise in humans, blood was sampled at 0.1 to 0.2 Hz from the radial artery and right...... internal jugular vein, while middle cerebral artery mean flow velocity (MCA V(mean)) was recorded. Both the arterial and venous lactate-to-pyruvate ratio increased after 10 s (P capillary...... state and oxygenation as potential modulators of an increase in cerebral blood flow at the onset of exercise....

  15. Effects of high temperature on survival, symbiotic performance and genomic modifications of bean nodulating Rhizobium strains Sobrevivência, fixação de nitrogênio e modificações genéticas em estirpes de Rhizobium sp. efetivas na nodulação do feijoeiro, expostas à altas temperaturas

    Directory of Open Access Journals (Sweden)

    Patrícia P. Pinto

    1998-10-01

    Full Text Available High temperatures can affect the survival, establishment and symbiotic properties of Rhizobium strains. Bean nodulating Rhizobium strains are considered particularly sensitive because on this strains genetic recombinations and/or deletions occur frequently, thus compromising the use of these bacteria as inoculants. In this study R. tropici and R. leguminosarum bv. phaseoli strains isolated from Cerrado soils were exposed to thermal stress and the strains’ growth, survival and symbiotic relationships as well as alterations in their genotypic and phenotypic characteristics were analyzed. After successive thermal shocks at 45ºC for four hours, survival capacity appeared to be strain-specific, independent of thermo-tolerance and was more apparent in R. tropici strains. Certain R. leguminosarum bv. phaseoli strains had significant alterations in plant dry weight and DNA patterns obtained by AP-PCR method. R. tropici strains (with the exception of FJ2.21 were more stable than R. leguminosarum bv. phaseoli strains because no significant phenotypic alterations were observed following thermal treatments and they maintained their original genotypic pattern after inoculation in plants.Altas temperaturas podem afetar a sobrevivência, estabelecimento e as propriedades simbióticas em estirpes de Rhizobium. As estirpes capazes de nodular o feijoeiro têm sido consideradas particularmente sensíveis, porque nessas estirpes é comum a ocorrência de recombinações e/ou deleções genômicas comprometendo, muitas vezes, a sua utilização como inoculantes. Neste trabalho, procurou-se avaliar a capacidade de crescimento e sobrevivência em temperaturas elevadas de estirpes de Rhizobium efetivas na fixação de nitrogênio no feijoeiro isoladas dos cerrados, bem como avaliar suas características fenotípicas e genotípicas após choque térmico. A capacidade de sobrevivência à temperaturas elevadas, avaliada após choques térmicos sucessivos (45ºC por 4

  16. Decreased expression of pyruvate dehydrogenase A1 predicts an unfavorable prognosis in ovarian carcinoma.

    Science.gov (United States)

    Li, Yaqing; Huang, Ruixia; Li, Xiaoli; Li, Xiaoran; Yu, Dandan; Zhang, Mingzhi; Wen, Jianguo; Goscinski, Mariusz Adam; Trope, Claes G; Nesland, Jahn M; Suo, Zhenhe

    2016-01-01

    Pyruvate dehydrogenase A1 (PDHA1) serves as a gate-keeper enzyme link between glycolysis and the mitochondrial citric acid cycle. The inhibition of PDHA1 in cancer cells can result in an increased Warburg effect and a more aggressive phenotype in cancer cells. This study was conducted to investigate the expression of PDHA1 in ovarian cancer and the correlation between PDHA1 expression and the prognosis of patients. The PDHA1 protein expression in 3 ovarian cancer cell lines (OVCAR-3, SKOV-3 and ES-2) and 248 surgically removed ovarian carcinoma samples was immunocytochemically examined. Statistical analyses were performed to evaluate the correlations between PDHA1 expression and the clinicopathological characteristics of the patients as well as the predictive value of PDHA1. The results showed the presence of variable expression of PDHA1 in the three ovarian cancer cell lines. Of the 248 ovarian cancer tissue specimens, 45 cases (18.1%) were negative in tumor cells for PDHA1, 162 cases (65.3%) displayed a low expression level, and 41 cases (16.5%) had a relatively high PDHA1 staining. The expression of PDHA1 was associated with the histological subtype ( P =0.004) and FIGO stage ( P =0.002). The median OS time in the PDHA1 negative group, low expression group and high expression group were 0.939 years, 1.443 years and 9.900 years, respectively. The median PFS time in the above three groups were 0.287 years, 0.586 years and 9.900 years, respectively. Furthermore, the high expression of PDHA1 in ovarian carcinoma cells was significantly associated with better OS and PFS by statistical analyses. Multivariate analyses showed that PDHA1 expression was also an independent prognostic factor for higher OS in ovarian cancer patients (HR=0.705, 95% CI 0.541-0.918, P =0.01). Our study indicated that the decreased expression of PDHA1 might be an independent prognostic factor in unfavorable outcomes.

  17. Plasticity of the Pyruvate Node Modulates Hydrogen Peroxide Production and Acid Tolerance in Multiple Oral Streptococci.

    Science.gov (United States)

    Cheng, Xingqun; Redanz, Sylvio; Cullin, Nyssa; Zhou, Xuedong; Xu, Xin; Joshi, Vrushali; Koley, Dipankar; Merritt, Justin; Kreth, Jens

    2018-01-15

    Commensal Streptococcus sanguinis and Streptococcus gordonii are pioneer oral biofilm colonizers. Characteristic for both is the SpxB-dependent production of H 2 O 2 , which is crucial for inhibiting competing biofilm members, especially the cariogenic species Streptococcus mutans H 2 O 2 production is strongly affected by environmental conditions, but few mechanisms are known. Dental plaque pH is one of the key parameters dictating dental plaque ecology and ultimately oral health status. Therefore, the objective of the current study was to characterize the effects of environmental pH on H 2 O 2 production by S. sanguinis and S. gordonii S. sanguinis H 2 O 2 production was not found to be affected by moderate changes in environmental pH, whereas S. gordonii H 2 O 2 production declined markedly in response to lower pH. Further investigation into the pyruvate node, the central metabolic switch modulating H 2 O 2 or lactic acid production, revealed increased lactic acid levels for S. gordonii at pH 6. The bias for lactic acid production at pH 6 resulted in concomitant improvement in the survival of S. gordonii at low pH and seems to constitute part of the acid tolerance response of S. gordonii Differential responses to pH similarly affect other oral streptococcal species, suggesting that the observed results are part of a larger phenomenon linking environmental pH, central metabolism, and the capacity to produce antagonistic amounts of H 2 O 2 IMPORTANCE Oral biofilms are subject to frequent and dramatic changes in pH. S. sanguinis and S. gordonii can compete with caries- and periodontitis-associated pathogens by generating H 2 O 2 Therefore, it is crucial to understand how S. sanguinis and S. gordonii adapt to low pH and maintain their competitiveness under acid stress. The present study provides evidence that certain oral bacteria respond to environmental pH changes by tuning their metabolic output in favor of lactic acid production, to increase their acid survival

  18. Enhanced pyruvate dehydrogenase activity improves cardiac outcomes in a murine model of cardiac arrest.

    Directory of Open Access Journals (Sweden)

    Lin Piao

    Full Text Available Post-ischemic changes in cellular metabolism alter myocardial and neurological function. Pyruvate dehydrogenase (PDH, the limiting step in mitochondrial glucose oxidation, is inhibited by increased expression of PDH kinase (PDK during ischemia/reperfusion injury. This results in decreased utilization of glucose to generate cellular ATP. Post-cardiac arrest (CA hypothermia improves outcomes and alters metabolism, but its influence on PDH and PDK activity following CA are unknown. We hypothesized that therapeutic hypothermia (TH following CA is associated with the inhibition of PDK activity and increased PDH activity. We further hypothesized that an inhibitor of PDK activity, dichloroacetate (DCA, would improve PDH activity and post-CA outcomes.Anesthetized and ventilated adult female C57BL/6 wild-type mice underwent a 12-minute KCl-induced CA followed by cardiopulmonary resuscitation. Compared to normothermic (37°C CA controls, administering TH (30°C improved overall survival (72-hour survival rate: 62.5% vs. 28.6%, P<0.001, post-resuscitation myocardial function (ejection fraction: 50.9±3.1% vs. 27.2±2.0%, P<0.001; aorta systolic pressure: 132.7±7.3 vs. 72.3±3.0 mmHg, P<0.001, and neurological scores at 72-hour post CA (9.5±1.3 vs. 5.4±1.3, P<0.05. In both heart and brain, CA increased lactate concentrations (1.9-fold and 3.1-fold increase, respectively, P<0.01, decreased PDH enzyme activity (24% and 50% reduction, respectively, P<0.01, and increased PDK protein expressions (1.2-fold and 1.9-fold, respectively, P<0.01. In contrast, post-CA treatment with TH normalized lactate concentrations (P<0.01 and P<0.05 and PDK expressions (P<0.001 and P<0.05, while increasing PDH activity (P<0.01 and P<0.01 in both the heart and brain. Additionally, treatment with DCA (0.2 mg/g body weight 30 min prior to CA improved both myocardial hemodynamics 2 hours post-CA (aortic systolic pressure: 123±3 vs. 96±4 mmHg, P<0.001 and 72-hour survival rates

  19. Expression of pyruvate dehydrogenase is an independent prognostic marker in gastric cancer

    Science.gov (United States)

    Sun, Xu-Ren; Sun, Zhe; Zhu, Zhi; Guan, Hai-Xia; Li, Chen-Yan; Zhang, Jun-Yan; Zhang, Yi-Ning; Zhou, Huan; Zhang, Hui-Jing; Xu, Hui-Mian; Sun, Ming-Jun

    2015-01-01

    AIM: To investigate the expression and prognostic role of pyruvate dehydrogenase (PDH) in gastric cancer (GC). METHODS: This study included 265 patients (194 male, 71 female, mean age 59 years (range, 29-81 years) with GC who underwent curative surgery at the First Affiliated Hospital of China Medical University from January 2006 to May 2007. All patients were followed up for more than 5 years. Patient-derived paraffin embedded GC specimens were collected for tissue microarrays (TMAs). We examined PDH expression by immunohistochemistry in TMAs containing tumor tissue and matched non-neoplastic mucosa. Immunoreactivity was evaluated independently by two researchers. Overall survival (OS) rates were determined using the Kaplan-Meier estimator. Correlations with other clinicopathologic factors were evaluated by two-tailed χ2 tests or a two-tailed t-test. The Cox proportional-hazard model was used in univariate analysis and multivariate analysis to identify factors significantly correlated with prognosis. RESULTS: Immunohistochemistry showed that 35.47% of total cancer tissue specimens had cytoplasmic PDH staining. PDH expression was much higher in normal mucosa specimens (75.09%; P = 0.001). PDH expression was correlated with Lauren grade (70.77% in intestinal type vs 40.0% in diffuse type; P = 0.001), lymph node metastasis (65.43% with no metastasis vs 51.09% with metastasis; P = 0.033), lymphatic invasion (61.62% with no invasion vs 38.81% with invasion; P = 0.002), histologic subtypes (70.77% in intestinal type vs 40.0% in diffuse type; P = 0.001) and tumor-node-metastasis (TNM) stage (39% in poorly differentiated vs 65.91% in well differentiated and 67.11% in moderately differentiated; P = 0.001) in GC. PDH expression in cancer tissue was significantly associated with higher OS (P < 0.001). The multivariate analysis adjusted for age, Lauren classification, TNM stage, lymph node metastasis, histological type, tumor size, depth of invasion and lymphatic invasion

  20. Parler et convaincre

    CERN Document Server

    Vigner, Gérard

    1979-01-01

    Dans l'apprentissage d'une langue, l'échange oral est avant tout utilitaire. On demande un renseignement, un prix, on salue, on remercie... On peut aussi parler pour exposer un point de vue, se justifier, entraîner une décision : parler pour convaincre. Cet ouvrage de la collection OUTILS veut aider les élèves à ce type d'intervention ; il leur fait d'abord analyser la situation de communication dans laquelle ils doivent intervenir, puis trouver les mots et expressions justes et efficaces. Sa structure et ses exercices permettent un travail tant collectif qu'individuel.

  1. Guerre et genre

    Directory of Open Access Journals (Sweden)

    Fabrice Virgili

    2010-01-01

    Full Text Available Ce mémoire d’habilitation à diriger des recherches comprend, sous le titre « Guerre et genre », trois volumes. Le rapport de synthèse (volume 3 retrace le parcours personnel et intellectuel de l’auteur autour de trois axes : Identités de genre et guerre, violence en temps de guerre, historiographie du genre. Le recueil (volume 2 comprend dix articles significatifs de ces thématiques. Enfin, le mémoire inédit (volume 1 porte sur les enfants nés de couple franco‑allemands pendant la Seconde ...

  2. Taiwo et al (15)

    African Journals Online (AJOL)

    Timothy Ademakinwa

    geometric rise in preference for commercial aquaculture .... content, malondialdehyde level and lipid content of the muscle of the .... other researchers on the gilthead sea bream (Mnari et al., 2007), the .... 23, Orlando, Florida, USA, pp. 18–28.

  3. Okusanya et al (5)

    African Journals Online (AJOL)

    DELL

    rainfall and number of days with rain per month were obtained from Meteorological Institute, Oshodi, Lagos- ... Central and South America, Australia, West. Indies, Africa, (Orwa et al., 2009) and in Florida .... dominant forest tree species. In this ...

  4. Lipochimie et innovations

    OpenAIRE

    Alfos Carine

    2003-01-01

    Peut-on parler d’un nouvel âge d’or pour les produits à base de ressources végétales renouvelables et notamment pour les huiles ? Porteurs de performances spécifiques et de caractéristiques plus écologiquement correctes, leur emploi ouvre à l’industrie un potentiel d’innovations auquel participe le département de chimie et rhéologie de l’Iterg. La prise de conscience collective, associée aux évolutions des réglementations françaises et européennes, devrait conduire les industries à prendre de...

  5. Obuotor et al (16)

    African Journals Online (AJOL)

    DELL

    fractions and essential oils from the leaves of Eugenia uniflora were investigated on some multidrug resistant pathogens. ... et al., 1987), a reduction in blood pressure measured ..... from E. uniflora suggests high efficacy against this bacterium.

  6. Fakinle et al (11)

    African Journals Online (AJOL)

    DELL

    management issues; there is however a concern about air emissions from the ... poses risks to humans and animals through ... Nigeria have focused on cement industries. (Adejumo et al. ... based MCA which controls the sample holder and.

  7. Hasard et chaos

    CERN Document Server

    Ruelle, David

    1991-01-01

    Comment expliquer le hasard ? Peut-on rendre raison de l'irraisonnable ? Ce livre, où il est question des jeux de dés, des loteries, des billards, des attracteurs étranges, de l'astrologie et des oracles, du temps qu'il fera, du libre arbitre, de la mécanique quantique, de l'écoulement des fluides, du théorème de Gödel et des limites de l'entendement humain, expose les fondements et les conséquences de la théorie du chaos. David Ruelle est membre de l'Académie des sciences et professeur de physique théorique à l'Institut des hautes études scientifiques de Bures-sur-Yvette.

  8. Omotayo et al (4)

    African Journals Online (AJOL)

    DELL

    using biochemical technique and API 20E identification system. The isolates were .... sulphate, phosphate, ammonia and appearance. Heavy metals ... technique as described by Collee et al. (1989) was ..... enzymatic methods. Water Res. 36,.

  9. David et al (12)

    African Journals Online (AJOL)

    DELL

    larger mesophyll cells, xylem tissues, vascular bundles and bundle sheaths than other cultivars. Thus, larger ... mechanism to cope with drought stress. There was an ... where solar radiation is intense (Løe et al., 2007). Most ecological studies ...

  10. Rhizobium leguminosarum COMO ORGANISMO BIOCONTROLADOR DE LA INTERACCIÓN HOSPEDERO-PATÓGENO: CLAVEL (Dianthus caryophyllus – Fusarium Oxysporum f. sp. dianthi

    Directory of Open Access Journals (Sweden)

    Cheol Woo Lee Park

    2010-08-01

    Full Text Available Se investigó el efecto de biocontrol de Rhizobium leguminosarum (R. leguminosarum cepa B, contra Fusarium oxysporum f.sp.dianthi (FOD raza 2, en la interacción Clavel - FOD. Se utilizó la raza 2 de FOD por ser la de mayor patogenicidad y distribución en las fincas de cultivo de clavel en Colombia. Para ello se establecieron las condiciones de inoculación de FOD sobre cultivos establecidos de R . leguminosarum, variando la concentración in vitro de la bacteria. Se encontró una reducción en el número de microconidias hasta un 90% y una inhibición en el crecimiento radial del patógeno de hasta un 71 %. En el ensayo de microcultivo dual se detectó fraccionamiento de las hifas después de 48 horas de incubación con R . leguminosarum En el ensayo in vivo, los esquejes de clavel Raggio di solé, variedad susceptible al patógeno, fueron inoculados con 45.0 x 10 células de R. leguminosarum por matero, mostrando una severidad inferior al 5%, una incidencia menor del 20% y una reducción del índice de la enfermedad hasta de un 92% en presencia del patógeno.

  11. The ethylene-inhibitor aminoethoxyvinylglycine restores normal nodulation by Rhizobium leguminosarum biovar. viciae on Vicia sativa subsp. nigra by suppressing the 'Thick and short roots' phenotype.

    Science.gov (United States)

    Zaat, S A; Van Brussel, A A; Tak, T; Lugtenberg, B J; Kijne, J W

    1989-02-01

    Nodulation of Vicia sativa subsp. nigra L. by Rhizobium bacteria is coupled to the development of thick and short roots (Tsr). This root phenotype as well as root-hair induction (Hai) and root-hair deformation (Had) are caused by a factor(s) produced by the bacteria in response to plant flavonoids. When very low inoculum concentrations (0.5-5 bacteria·ml(-1)) were used, V. sativa plants did not develop the Tsr phenotype and became nodulated earlier than plants with Tsr roots. Furthermore, the nodules of these plants were located on the primary root in contrast to nodules on Tsr roots, which were all located at sites of lateral-root emergence. The average numbers of nodules per plant were not significantly different for these two types of nodulation. Root-growth inhibition and Hai, but not Had, could be mimicked by ethephon, and inhibited by aminoethoxyvinylglycine (AVG). Addition of AVG to co-cultures of Vicia sativa and the standard inoculum concentration of 5·10(5) bacteria·ml(-1) suppressed the development of the Tsr phenotype and restored nodulation to the pattern that was observed with very low concentrations of bacteria (0.5-5 bacteria·ml(-1)). The delay in nodulation on Tsr roots appeared to be caused by the fact that nodule meristems did not develop on the primary root, but only on the emerging laterals. The relationship between Tsr, Hai, Had, and nodulation is discussed.

  12. UV-radiation induced changes in antibiotic markers, chemical composition of water soluble polysaccharides and nodulation ability of Rhizobium trifolic 11B

    International Nuclear Information System (INIS)

    Ghai, Jyotsna; Ghai, S.K.; Kalra, M.S.

    1983-01-01

    Rhizobium trifolii 11B, which formed effective nodules on its host. Trifolium alexanderinum L. was UV-irradiated to isolate mutants. Out of the 9 variants isolated only 1 strain, viz. 21M11B produced more water soluble polysaccharide [752 mg (100 ml -1 )] than the parent 15 different antibiotics was similar only in two (22M11B and 26M11B) of the 9 UV-mutants. Compositional studies revealed that the water soluble polysaccharides from all strains contained glucose and galactose in the molar ratio of 7:1. Glucuronic acid which was present (2.33 per cent) in the water soluble polysaccharide from strain 11B was absent in all but 2UV-mutants (4.22per cent in 6M11B and 4.04per cent in26M11B). Five of the UB-mutants (1M11B, 17M11B, 20N11B, 22M11B and 26M11B) were Nod - . The organisms which produced more water soluble polysaccharide upon infection of the plants induced the formation of more number of nodules. (author)

  13. Formulation of microbes inoculum: AMF, PSB and Rhizobium isolated of ex-coal mining site for Acacia crassicarpa Cunn. Ex-benth seedlings

    Directory of Open Access Journals (Sweden)

    ENNY WIDYATI

    2007-07-01

    Full Text Available The shoddier succeed land revegetation particularly caused by least adaptability of the seedlings planted on this site. To encourage their growth and survival rate it can be achieved by means do inoculation with the compatible functional microbes such as rhizobium, Psolubilizing bacteria (PSB and/or arbuscular-mycorrhiza fungy (AMF. This reserach is aimed to formulate the most compatible inoculant to support the growth of A. crassicarpa seedlings. Compatibility study is carried out in RCB design with 3 replications, each contain 5 seedlings. Height and biomass are accessed to measure the growth responses of the seedlings. The result showed that the best reponse is given by consortia that consist of the three kinds of these microbes. This increase the shoot biomass (137% compare to the control. The consortia also improved N 164%, P 335% and K 167% in the plant tissues. While pure AMF improved absorption of N plants 80%, P 383% and K 51% compare to the control. It is suggested that to prepare the A. crassicarpa seedlings is better inoculated by consortium of microbes or AMF as a sole inoculant.

  14. Bacteria–zinc co-localization implicates enhanced synthesis of cysteine-rich peptides in zinc detoxification when Brassica juncea is inoculated with Rhizobium leguminosarum

    Science.gov (United States)

    Adediran, Gbotemi A; Ngwenya, Bryne T; Mosselmans, J Frederick W; Heal, Kate V

    2016-01-01

    Some plant growth promoting bacteria (PGPB) are enigmatic in enhancing plant growth in the face of increased metal accumulation in plants. Since most PGPB colonize the plant root epidermis, we hypothesized that PGPB confer tolerance to metals through changes in speciation at the root epidermis. We employed a novel combination of fluorophore-based confocal laser scanning microscopic imaging and synchrotron based microscopic X-ray fluorescence mapping with X-ray absorption spectroscopy to characterize bacterial localization, zinc (Zn) distribution and speciation in the roots of Brassica juncea grown in Zn contaminated media (400 mg kg−1 Zn) with the endophytic Pseudomonas brassicacearum and rhizospheric Rhizobium leguminosarum. PGPB enhanced epidermal Zn sequestration relative to PGBP-free controls while the extent of endophytic accumulation depended on the colonization mode of each PGBP. Increased root accumulation of Zn and increased tolerance to Zn was associated predominantly with R. leguminosarum and was likely due to the coordination of Zn with cysteine-rich peptides in the root endodermis, suggesting enhanced synthesis of phytochelatins or glutathione. Our mechanistic model of enhanced Zn accumulation and detoxification in plants inoculated with R. leguminosarum has particular relevance to PGPB enhanced phytoremediation of soils contaminated through mining and oxidation of sulphur-bearing Zn minerals or engineered nanomaterials such as ZnS. PMID:26263508

  15. Rhizobium leguminosarum bv. viciae 3841 Adapts to 2,4-Dichlorophenoxyacetic Acid with "Auxin-Like" Morphological Changes, Cell Envelope Remodeling and Upregulation of Central Metabolic Pathways.

    Directory of Open Access Journals (Sweden)

    Supriya V Bhat

    Full Text Available There is a growing need to characterize the effects of environmental stressors at the molecular level on model organisms with the ever increasing number and variety of anthropogenic chemical pollutants. The herbicide 2,4-dichlorophenoxyacetic acid (2,4-D, as one of the most widely applied pesticides in the world, is one such example. This herbicide is known to have non-targeted undesirable effects on humans, animals and soil microbes, but specific molecular targets at sublethal levels are unknown. In this study, we have used Rhizobium leguminosarum bv. viciae 3841 (Rlv as a nitrogen fixing, beneficial model soil organism to characterize the effects of 2,4-D. Using metabolomics and advanced microscopy we determined specific target pathways in the Rlv metabolic network and consequent changes to its phenotype, surface ultrastructure, and physical properties during sublethal 2,4-D exposure. Auxin and 2,4-D, its structural analogue, showed common morphological changes in vitro which were similar to bacteroids isolated from plant nodules, implying that these changes are related to bacteroid differentiation required for nitrogen fixation. Rlv showed remarkable adaptation capabilities in response to the herbicide, with changes to integral pathways of cellular metabolism and the potential to assimilate 2,4-D with consequent changes to its physical and structural properties. This study identifies biomarkers of 2,4-D in Rlv and offers valuable insights into the mode-of-action of 2,4-D in soil bacteria.

  16. UNION ECONOMIQUE ET MONETAIRE

    International Development Research Centre (IDRC) Digital Library (Canada)

    aagmohamed

    Monsieur le Vice-président du Centre de Recherche pour le Développement. International,. Messieurs les Présidents de la Cour de Justice et de la Cour des Comptes ;. Chers collègues Commissaires de l'UEMOA ;. Monsieur le Commissaire de la CEDEAO,. Messieurs les membres de la Cour de Justice et de la Cour des ...

  17. CARACTERISATION MORPHOLOGIQUE ET PHYSIOLOGIQUE ...

    African Journals Online (AJOL)

    AISA

    de la terre et du papier filtre stériles. La germination sur chacun des substrats a été réalisée dans les conditions d'obscurité continue. (COC) et de photopériode naturelle (CPN) pendant 3 semaines. Le laboratoire a servi de cadre à la conduite de la germination sur papier comme support. Des rondelles de papiers.

  18. Mondialisation, Croissance et Marginalisation

    International Development Research Centre (IDRC) Digital Library (Canada)

    Dans la mesure où les pays en développement se sont tournés ..... Une gestion judicieuse du commerce et des flux de capitaux est donc nécessaire ..... On peut donc se demander s'il faudrait reprendre le contrôle des marchés financiers. ...... 100 par année entre 1950 et 1980, une performance qui n'a été surpassée de ...

  19. Cisjordanie et Gaza

    International Development Research Centre (IDRC) Digital Library (Canada)

    Cathy Egan

    recherches fructueuses pour le développement au cœur même des plus grands dangers et de privations extrêmes. ... 70 projets en Cisjordanie et à Gaza depuis le milieu des années 1980. ... Des études de cas ont été préparées sur l'Algérie ...

  20. Effects of adrenergic agents on intracellular ca(2+) homeostasis and metabolism of glucose in astrocytes with an emphasis on pyruvate carboxylation, oxidative decarboxylation and recycling

    DEFF Research Database (Denmark)

    Obel, Linea Lykke Frimodt; Andersen, Karen M H; Bak, Lasse Kristoffer

    2012-01-01

    and oxidative decarboxylation in astrocytic glucose metabolism. Importantly, pyruvate carboxylation was best visualized at 10 min of incubation. The abundance and pattern of labeling in lactate and alanine indicated not only an extensive activity of malic enzyme (initial step for pyruvate recycling) but also...... a high degree of compartmentalization of the pyruvate pool. Stimulating with 1 µM NE had no effect on labeling patterns and glycogen metabolism, whereas 100 µM NE increased glutamate labeling and decreased labeling in alanine, the latter supposedly due to dilution from degradation of non-labeled glycogen....... It is suggested that further experiments uncovering the correlation between adrenergic and glutamatergic pathways should be performed in order to gain further insight into the role of astrocytes in brain function and dysfunction, the latter including excitotoxicity....

  1. Overexpression of pyruvate decarboxylase in the yeast Hansenula polymorpha results in increased ethanol yield in high-temperature fermentation of xylose.

    Science.gov (United States)

    Ishchuk, Olena P; Voronovsky, Andriy Y; Stasyk, Oleh V; Gayda, Galina Z; Gonchar, Mykhailo V; Abbas, Charles A; Sibirny, Andriy A

    2008-11-01

    Improvement of xylose fermentation is of great importance to the fuel ethanol industry. The nonconventional thermotolerant yeast Hansenula polymorpha naturally ferments xylose to ethanol at high temperatures (48-50 degrees C). Introduction of a mutation that impairs ethanol reutilization in H. polymorpha led to an increase in ethanol yield from xylose. The native and heterologous (Kluyveromyces lactis) PDC1 genes coding for pyruvate decarboxylase were expressed at high levels in H. polymorpha under the control of the strong constitutive promoter of the glyceraldehyde-3-phosphate dehydrogenase gene (GAPDH). This resulted in increased pyruvate decarboxylase activity and improved ethanol production from xylose. The introduction of multiple copies of the H. polymorpha PDC1 gene driven by the strong constitutive promoter led to a 20-fold increase in pyruvate decarboxylase activity and up to a threefold elevation of ethanol production.

  2. Intraperitoneal lactate/pyruvate ratio and the level of glucose and glycerol concentration differ between patients surgically treated for upper and lower perforations of the gastrointestinal tract

    DEFF Research Database (Denmark)

    Sabroe, Jonas E; Axelsen, Anne R; Ellebæk, Mark B

    2017-01-01

    collected every 4th hour for up to 7 postoperative days. Samples were analysed for concentrations of glucose, lactate, pyruvate and glycerol. RESULTS: Microdialysis results showed that patients with upper gastrointestinal tract lesions had significantly higher levels of postoperative intraperitoneal glucose...... and glycerol concentrations, as well as lower lactate/pyruvate ratios and lactate/glucose ratios. In the group with perforation of the lower gastrointestinal tract, those patients with a complicated course showed lower levels of postoperative intraperitoneal glucose concentration and glycerol concentration...... and higher lactate/pyruvate ratios and lactate/glucose ratios than those patients with an uncomplicated course. CONCLUSION: Patients with upper and lower gastrointestinal tract lesions showed differences in postoperative biomarker levels. A difference was also seen between patients with complicated...

  3. Molecular identification and characterization of the pyruvate decarboxylase gene family associated with latex regeneration and stress response in rubber tree.

    Science.gov (United States)

    Long, Xiangyu; He, Bin; Wang, Chuang; Fang, Yongjun; Qi, Jiyan; Tang, Chaorong

    2015-02-01

    In plants, ethanolic fermentation occurs not only under anaerobic conditions but also under aerobic conditions, and involves carbohydrate and energy metabolism. Pyruvate decarboxylase (PDC) is the first and the key enzyme of ethanolic fermentation, which branches off the main glycolytic pathway at pyruvate. Here, four PDC genes were isolated and identified in a rubber tree, and the protein sequences they encode are very similar. The expression patterns of HbPDC4 correlated well with tapping-simulated rubber productivity in virgin rubber trees, indicating it plays an important role in regulating glycometabolism during latex regeneration. HbPDC1, HbPDC2 and HbPDC3 had striking expressional responses in leaves and bark to drought, low temperature and high temperature stresses, indicating that the HbPDC genes are involve in self-protection and defense in response to various abiotic and biotic stresses during rubber tree growth and development. To understand ethanolic fermentation in rubber trees, it will be necessary to perform an in-depth study of the regulatory pathways controlling the HbPDCs in the future. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  4. Mitochondrial pyruvate carrier function is negatively linked to Warburg phenotype in vitro and malignant features in esophageal squamous cell carcinomas

    Science.gov (United States)

    Li, Yaqing; Li, Xiaoran; Kan, Quancheng; Zhang, Mingzhi; Li, Xiaoli; Xu, Ruiping; Wang, Junsheng; Yu, Dandan; Goscinski, Mariusz Adam; Wen, Jian-Guo; Nesland, Jahn M.; Suo, Zhenhe

    2017-01-01

    Aerobic glycolysis is one of the emerging hallmarks of cancer cells. In this study, we investigated the relationship between blocking mitochondrial pyruvate carrier (MPC) with MPC blocker UK5099 and the metabolic alteration as well as aggressive features of esophageal squamous carcinoma. It was found that blocking pyruvate transportation into mitochondria attenuated mitochondrial oxidative phosphorylation (OXPHOS) and triggered aerobic glycolysis, a feature of Warburg effect. In addition, the HIF-1α expression and ROS production were also activated upon UK5099 application. It was further revealed that the UK5099-treated cells became significantly more resistant to chemotherapy and radiotherapy, and the UK5099-treated tumor cells also exhibited stronger invasive capacity compared to the parental cells. In contrast to esophageal squamous epithelium cells, decreased MPC protein expression was observed in a series of 157 human squamous cell carcinomas, and low/negative MPC1 expression predicted an unfavorable clinical outcome. All these results together revealed the potential connection of altered MPC expression/activity with the Warburg metabolic reprogramming and tumor aggressiveness in cell lines and clinical samples. Collectively, our findings highlighted a therapeutic strategy targeting Warburg reprogramming of human esophageal squamous cell carcinomas. PMID:27911865

  5. Escherichia coli pyruvate dehydrogenase complex: particle masses of the complex and component enzymes measured by scanning transmission electron microscopy

    International Nuclear Information System (INIS)

    CaJacob, C.A.; Frey, P.A.; Hainfeld, J.F.; Wall, J.S.; Yang, H.

    1985-01-01

    Particle masses of the Escherichia coli pyruvate dehydrogenase (PDH) complex and its component enzymes have been measured by scanning transmission electron microscopy (STEM). The particle mass of PDH complex measured by STEM is 5.28 X 10(6) with a standard deviation of 0.40 X 10(6). The masses of the component enzymes are 2.06 X 10(5) for the dimeric pyruvate dehydrogenase (E1), 1.15 X 10(5) for dimeric dihydrolipoyl dehydrogenase (E3), and 2.20 X 10(6) for dihydrolipoyl transacetylase (E2), the 24-subunit core enzyme. STEM measurements on PDH complex incubated with excess E3 or E1 failed to detect any additional binding of E3 but showed that the complex would bind additional E1 under forcing conditions. The additional E1 subunits were bound too weakly to represent binding sites in an isolated or isolable complex. The mass measurements by STEM are consistent with the subunit composition 24:24:12 when interpreted in the light of the flavin content of the complex and assuming 24 subunits in the core enzyme (E2)

  6. Effect of Pyruvate Decarboxylase Knockout on Product Distribution Using Pichia pastoris (Komagataella phaffii) Engineered for Lactic Acid Production.

    Science.gov (United States)

    Melo, Nadiele T M; Mulder, Kelly C L; Nicola, André Moraes; Carvalho, Lucas S; Menino, Gisele S; Mulinari, Eduardo; Parachin, Nádia S

    2018-02-16

    Lactic acid is the monomer unit of the bioplastic poly-lactic acid (PLA). One candidate organism for lactic acid production is Pichia pastoris , a yeast widely used for heterologous protein production. Nevertheless, this yeast has a poor fermentative capability that can be modulated by controlling oxygen levels. In a previous study, lactate dehydrogenase (LDH) activity was introduced into P. pastoris, enabling this yeast to produce lactic acid. The present study aimed to increase the flow of pyruvate towards the production of lactic acid in P. pastoris . To this end, a strain designated GLp was constructed by inserting the bovine lactic acid dehydrogenase gene (LDHb) concomitantly with the interruption of the gene encoding pyruvate decarboxylase (PDC). Aerobic fermentation, followed by micro-aerophilic culture two-phase fermentations, showed that the GLp strain achieved a lactic acid yield of 0.65 g/g. The distribution of fermentation products demonstrated that the acetate titer was reduced by 20% in the GLp strain with a concomitant increase in arabitol production: arabitol increased from 0.025 g/g to 0.174 g/g when compared to the GS115 strain. Taken together, the results show a significant potential for P. pastoris in producing lactic acid. Moreover, for the first time, physiological data regarding co-product formation have indicated the redox balance limitations of this yeast.

  7. miR-378 Activates the Pyruvate-PEP Futile Cycle and Enhances Lipolysis to Ameliorate Obesity in Mice

    Directory of Open Access Journals (Sweden)

    Yong Zhang

    2016-03-01

    Full Text Available Obesity has been linked to many health problems, such as diabetes. However, there is no drug that effectively treats obesity. Here, we reveal that miR-378 transgenic mice display reduced fat mass, enhanced lipolysis, and increased energy expenditure. Notably, administering AgomiR-378 prevents and ameliorates obesity in mice. We also found that the energy deficiency seen in miR-378 transgenic mice was due to impaired glucose metabolism. This impairment was caused by an activated pyruvate-PEP futile cycle via the miR-378-Akt1-FoxO1-PEPCK pathway in skeletal muscle and enhanced lipolysis in adipose tissues mediated by miR-378-SCD1. Our findings demonstrate that activating the pyruvate-PEP futile cycle in skeletal muscle is the primary cause of elevated lipolysis in adipose tissues of miR-378 transgenic mice, and it helps orchestrate the crosstalk between muscle and fat to control energy homeostasis in mice. Thus, miR-378 may serve as a promising agent for preventing and treating obesity in humans.

  8. Répartition et abondance des sargasses Sargassum natans et ...

    African Journals Online (AJOL)

    Ces plantes se retrouvent en abondance en mai et en juin sur toutes les plages du pays et particulièrement sur les plages du secteur littoral centre et oriental et les complexes lagunaires Aby-Tendo-Ehy et Grand-Lahou. Leur expansion en mai dans tous les milieux est favorisée par la salinité, la lumière, la température et ...

  9. Comparative kinetic studies of Mn2+-activated and fructose-1,6-P-modified Mg2+-activated pyruvate kinase from Concholepas concholepas.

    Science.gov (United States)

    Carvajal, N; González, R; Morán, A; Oyarce, A M

    1985-01-01

    Initial velocity and product inhibition studies of Mn2+-activated and FDP-modified Mg2+-activated pyruvate kinase from Concholepas concholepas, were performed. Evidence is presented to show that the Mn2+-enzyme catalyzes an ordered sequential mechanism, with ADP being the first substrate and pyruvate the last product. The results presented are consistent with a random combination of reactants with the FDP-modified Mg2+-activated enzyme and the formation of the dead-end complexes enzyme ADP-ATP and enzyme-PEP-ATP.

  10. Drague et cruising

    Directory of Open Access Journals (Sweden)

    Emmanuel Redoutey

    2008-04-01

    Full Text Available Dans la culture homosexuelle masculine, drague et cruising sont des termes équivalents. Ils désignent la quête d’un ou de plusieurs partenaires occasionnels et anonymes. Analyser leurs référents métaphoriques respectifs offre un éclairage particulier, à la fois phénoménologique et géographique, pour une compréhension nuancée des types de pratique et d’expérience qu’ils recouvrent. Cet article pose l’hypothèse d’une distinction entre deux figures, le dragueur et le cruiser, et postule que cette distinction se tient essentiellement dans l’opposition que Gilles Deleuze et Félix Guattari établissent entre ‘espace strié’ et ‘espace lisse’. L’essai de théorisation qui en découle est une manière de comprendre ce qui, entre sexualisation de l’espace et érotisation d’un mouvement exploratoire, fait fonctionner le script de la drague.In French gay culture, drague means cruising: looking for anonymous and 
casual sexual partners. This paper, by respectively examining the 
metaphorical underpinnings of both words, French and English, throws 
doubt on the validity of this translation. Through a phenomenological 
and geographical perspective, it attempts to give a nuanced examination 
of the practice and experience that each word conceals. The aim is to 
identify two figures embodied in a same person: the dragueur and the 
cruiser. I will argue that the distinction mainly rests on the 
opposition that Gilles Deleuze and Felix Guattari establish between ‘striated space’ and ‘smooth space’. The concluding theorical 
discussion is an attempt to understand what, in the tension between sexualization of space and eroticization of movement, guides the scripts of drague and cruising.

  11. Paraboles et catastrophes

    CERN Document Server

    Thom, René

    1983-01-01

    René Thom, mathématicien français, membre de l'Académie des Sciences, s'est vu décerner en 1958 la médaille Field, équivalent du Prix Nobel en mathématiques, pour ses créations intellectuelles, la " théorie des catastrophes ", regard nouveau sur toutes les transformations qui adviennent de manière brusque, imprévisible, dramatique. Dans ces entretiens qui vont de la mathématique à l'embryologie, de la linguistique à l'anthropologie et à l'histoire, René Thom expose les grandes lignes de la théorie des catastrophes et passe en revue, avec un esprit à la fois critique et passionné, les grands thèmes scientifiques de notre époque, de la physique atomique à la biologie moléculaire, du " progrès " scientifique et technologique aux connexions complexes entre la société et la science. " Ce petit livre est une extraordinaire réussite en vulgarisation ". (Jean Largeault)

  12. Enfants, chercheurs et citoyens

    CERN Document Server

    Lederman, Leon

    1998-01-01

    J'ai consacré ma vie à la physique. J'aimerais que tous les enfants aient la chance de satisfaire leur goût pour la recherche et de développer leur intelligence. J'ai découvert à Chicago, chez mon ami Leon Lederman, une méthode d'enseignement des sciences à l'école qui m'a subjugué. J'ai vu, à tous les niveaux, en physique, en chimie, en sciences naturelles et en mathématiques, des enfants qui expérimentaient avec joie, apprenaient les concepts fondamentaux à leur rythme, réfléchissant et discutant. Je voyais en gestation des êtres libres, capables de rechercher une vérité qui ne leur était pas assenée. J'ai voulu confronter des enseignants français du primaire et du secondaire à ces recherches qui ne se limitent pas à l'enseignement primaire. C'est leur regard critique et surtout leurs idées pour notre enseignement que j'ai rassemblés dans ce livre.

  13. Efeito residual da vinhaça na população autóctone de Rhizobium do solo Residual effects of sugar cane vinasse on indigenous Rhizobia

    Directory of Open Access Journals (Sweden)

    Eli Sidney Lopes

    1986-01-01

    Full Text Available A adição de vinhaça na cultura canavieira tem sido praticada em áreas próximas às usinas de cana. Seria de interesse a avaliação do efeito da vinhaça no Rhizobium presente no solo (autóctone, uma vez que leguminosas têm sido indicadas para cultivo intercalar com a cana. Um experimento foi conduzido em casa de vegetação, com o objetivo de verificar a influência da aplicação contínua, durante três anos, de concentrações crescentes de vinhaça (0, 100 e 1.000 m³/ha/ano, com intervalos de seis meses entre aplicações, na população autóctone de Rhizobium que nodula amendoim, soja, feijão e crotalária. Em cada cultura, foram usados controle com solo sem adição da vinhaça e um tratamento inoculado com uma estirpe de Rhizobium de conhecida eficiência, recomendada para a cultura. Uma análise do efeito de uma dose adicional de 1,5 ppm do herbicida 2,4-D no tratamento com 100 m³/ha/ano foi também efetuada. Apesar de os resultados serem variados entre as culturas, ocorreram efeitos da vinhaça sobre a população de Rhizobium, causando aumentos de nodulação na crotalária e diminuição no amendoim. Não foram observados efeitos na nodulação do feijoeiro em nenhum dos tratamentos com a vinhaça, nem na soja, que nodulou somente com a dose mais elevada, sugerindo que o Rhizobium japonicum no solo estudado estava presente em baixo número. O tratamento com herbicida mostrou tendência de favorecer a nodulação e, conseqüentemente, a fixação biológica de N2, medida através do N na planta.The addition of vinasse on sugar cane plantations nearby alcohol fermentation plants is a common practice. Legumes are recommended to be intercropped with sugar cane. A greenhouse experiment was carried out with the objective of verifying the influence of continuous application of vinasse (0; 100 and 1000 m³/ha/year at six month interval during three years on soil rhizobia which nodulate peanuts, soybeans, dry-beans and crotalaria

  14. Artaud et les Tarahumaras

    Directory of Open Access Journals (Sweden)

    Marta Mariasole Raimondi

    2008-01-01

    Full Text Available Ce film propose des scènes de vie des Tarahumaras, une ethnie originaire du Mexique installée dans le territoire de l'Etat de Chiuahua, dans un milieu montagneux très sauvage. La caméra reprend les danses et les rites de ces mangeurs de peyotl d'un regard rapide et saccadé primant des cadrages de détail où prédominent les pieds, pour nous montrer ces corps d'homme et de femme en mouvement, courant, dansant, bondissant au milieu des leurs éléments naturels : rocailles, rivières, rochers, sans...

  15. Pastourelle et folklore

    OpenAIRE

    Dumas, René

    2014-01-01

    Dans l'état où il nous est parvenu, le Tristan de Béroul ne nous offre que peu d'évocations de la ville et de la demeure où évoluent les différents personnages. Pourtant, bon nombre des moments-clés du roman se situent précisément en milieu urbain : la scène de la marche au suplice d'Iseut, par exemple, ou celle de la fête qui célèbre son retour auprès du roi Marc. Aussi tenterons-nous de préciser dans quel cadre de vie se situent les aventures de Tristan et Iseut et de rechercher l'ordre urb...

  16. Travaux et publications

    OpenAIRE

    M. Deville

    2010-01-01

    Ouvrages L'Oratoire à Angers aux xviie et xviiie siècles, Paris, 1975, 251 p. Le pouvoir municipal à Angers de 1657 à 1789, 2 vol., Angers, 1984, 293 et 348 p. Articles « La mission du père Honoré de Cannes à Angers en 1684 », Annales de Bretagne et des Pays de l'ouest (en abrégé ABPO dans les articles suivants), 1974, p. 501-516. « L'élection des maires d'Angers au xviiie siècle », Travaux sur le xviiie siècle, Angers, 1978, p 4-18. « Les messagers de l'université d'Angers dans la seconde mo...

  17. Pluralisme et rupture familiale

    OpenAIRE

    Fulchiron, Hugues

    2012-01-01

    Le modèle familial au sein de notre société est la famille nucléaire mariée composée des conjoints et des enfants et parfois étendue à d’autres parents, tels que les grands-parents. Avant la deuxième guerre mondiale le schéma était différent ; la famille type était constituée de plusieurs générations. Cette coopérative familiale était fondée sur l’autorité du chef de famille et la hiérarchie stricte de l’autorité familiale. La femme était donc d’abord soumise à son père puis à son mari ou à s...

  18. Hvad karakteriserer et talent?

    DEFF Research Database (Denmark)

    Raalskov, Jesper

    2012-01-01

    Debatten i medierne har i stigende grad fokus på talentfulde medarbejdere - men hvad er talent egentlig? I den akademiske litteratur inden for Talent Management (TM) gives der mange forskellige bud på, hvordan man som virksomhed kan udvikle og lede talenter, men færre af feltets inputgivere...... forholder sig til, hvad den overordnede definition af talent er. Der ses i litteraturen divergerende opfattelser af, hvilke konkrete egenskaber (attributter) som definerer et talent. I denne artikel gives et bud på en konsensusskabende tilgang til talent, idet talent kan ses som; det du har gjort (fortid...

  19. An internal deletion in MTH1 enables growth on glucose of pyruvate-decarboxylase negative, non-fermentative Saccharomyces cerevisiae.

    Science.gov (United States)

    Oud, Bart; Flores, Carmen-Lisset; Gancedo, Carlos; Zhang, Xiuying; Trueheart, Joshua; Daran, Jean-Marc; Pronk, Jack T; van Maris, Antonius J A

    2012-09-15

    Pyruvate-decarboxylase negative (Pdc⁻) strains of Saccharomyces cerevisiae combine the robustness and high glycolytic capacity of this yeast with the absence of alcoholic fermentation. This makes Pdc⁻S. cerevisiae an interesting platform for efficient conversion of glucose towards pyruvate-derived products without formation of ethanol as a by-product. However, Pdc⁻ strains cannot grow on high glucose concentrations and require C₂-compounds (ethanol or acetate) for growth under conditions with low glucose concentrations, which hitherto has limited application in industry. Genetic analysis of a Pdc⁻ strain previously evolved to overcome these deficiencies revealed a 225 p in-frame internal deletion in MTH1, encoding a transcriptional regulator involved in glucose sensing. This internal deletion contains a phosphorylation site required for degradation, thereby hypothetically resulting in increased stability of the protein. Reverse engineering of this alternative MTH1 allele into a non-evolved Pdc⁻ strain enabled growth on 20 g l⁻¹ glucose and 0.3% (v/v) ethanol at a maximum specific growth rate (0.24 h⁻¹) similar to that of the evolved Pdc⁻ strain (0.23 h⁻¹). Furthermore, the reverse engineered Pdc⁻ strain grew on glucose as sole carbon source, albeit at a lower specific growth rate (0.10 h⁻¹) than the evolved strain (0.20 h⁻¹). The observation that overexpression of the wild-type MTH1 allele also restored growth of Pdc⁻S. cerevisiae on glucose is consistent with the hypothesis that the internal deletion results in decreased degradation of Mth1. Reduced degradation of Mth1 has been shown to result in deregulation of hexose transport. In Pdc⁻ strains, reduced glucose uptake may prevent intracellular accumulation of pyruvate and/or redox problems, while release of glucose repression due to the MTH1 internal deletion may contribute to alleviation of the C₂-compound auxotrophy. In this study we have discovered and characterised a

  20. An internal deletion in MTH1 enables growth on glucose of pyruvate-decarboxylase negative, non-fermentative Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Oud Bart

    2012-09-01

    Full Text Available Abstract Background Pyruvate-decarboxylase negative (Pdc- strains of Saccharomyces cerevisiae combine the robustness and high glycolytic capacity of this yeast with the absence of alcoholic fermentation. This makes Pdc-S. cerevisiae an interesting platform for efficient conversion of glucose towards pyruvate-derived products without formation of ethanol as a by-product. However, Pdc- strains cannot grow on high glucose concentrations and require C2-compounds (ethanol or acetate for growth under conditions with low glucose concentrations, which hitherto has limited application in industry. Results Genetic analysis of a Pdc- strain previously evolved to overcome these deficiencies revealed a 225bp in-frame internal deletion in MTH1, encoding a transcriptional regulator involved in glucose sensing. This internal deletion contains a phosphorylation site required for degradation, thereby hypothetically resulting in increased stability of the protein. Reverse engineering of this alternative MTH1 allele into a non-evolved Pdc- strain enabled growth on 20 g l-1 glucose and 0.3% (v/v ethanol at a maximum specific growth rate (0.24 h-1 similar to that of the evolved Pdc- strain (0.23 h-1. Furthermore, the reverse engineered Pdc- strain grew on glucose as sole carbon source, albeit at a lower specific growth rate (0.10 h-1 than the evolved strain (0.20 h-1. The observation that overexpression of the wild-type MTH1 allele also restored growth of Pdc-S. cerevisiae on glucose is consistent with the hypothesis that the internal deletion results in decreased degradation of Mth1. Reduced degradation of Mth1 has been shown to result in deregulation of hexose transport. In Pdc- strains, reduced glucose uptake may prevent intracellular accumulation of pyruvate and/or redox problems, while release of glucose repression due to the MTH1 internal deletion may contribute to alleviation of the C2-compound auxotrophy. Conclusions In this study we have discovered and