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Sample records for central carbon metabolism

  1. Phenotypic bistability in Escherichia coli's central carbon metabolism

    NARCIS (Netherlands)

    Kotte, Oliver; Volkmer, Benjamin; Radzikowski, Jakub L.; Heinemann, Matthias

    2014-01-01

    Fluctuations in intracellular molecule abundance can lead to distinct, coexisting phenotypes in isogenic populations. Although metabolism continuously adapts to unpredictable environmental changes, and although bistability was found in certain substrate-uptake pathways, central carbon metabolism is

  2. Reconstruction of the central carbon metabolism of Aspergillus niger

    DEFF Research Database (Denmark)

    David, Helga; Åkesson, Mats Fredrik; Nielsen, Jens

    2003-01-01

    The topology of central carbon metabolism of Aspergillus niger was identified and the metabolic network reconstructed, by integrating genomic, biochemical and physiological information available for this microorganism and other related fungi. The reconstructed network may serve as a valuable...

  3. Rewriting central metabolism for carbon conservation

    OpenAIRE

    Bogorad, Igor Walter

    2015-01-01

    The efficient use of carbon sources is a core objective in metabolic engineering and biorefinery. Most approaches have focused on optimizing naturally occurring pathways to improve titer, productivity, and yield. However, certain inherent limitations cannot be surpassed if natural pathways are used. Here we designed two synthetic metabolic pathways, Non-Oxidative Glycolysis (NOG) and Methanol Condensation Cycle (MCC) for the utilization of sugar and methanol, respectively. We also created a ...

  4. Central carbon metabolism in the progression of mammary carcinoma

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    Richardson, Adam D.; Yang, Chen; Osterman, Andrei

    2007-01-01

    There is a growing belief that the metabolic program of breast tumor cells could be a therapeutic target. Yet, without detailed information on central carbon metabolism in breast tumors it is impossible to know which metabolic pathways to target, and how their inhibition might influence different stages of breast tumor progression. Here we perform the first comprehensive profiling of central metabolism in the MCF10 model of mammary carcinoma, where the steps of breast tumor progression (transformation, tumorigenicity and metastasis) can all be examined in the context of the same genetic background. The metabolism of [U-13C]-glucose by a series of progressively more aggressive MCF10 cell lines was tracked by 2D NMR and mass spectrometry. From this analysis the flux of carbon through distinct metabolic reactions was quantified by isotopomer modeling. The results indicate widespread changes to central metabolism upon cellular transformation including increased carbon flux through the pentose phosphate pathway (PPP), the TCA cycle, as well as increased synthesis of glutamate, glutathione and fatty acids (including elongation and desaturation). The de novo synthesis of glycine increased upon transformation as well as at each subsequent step of breast tumor cell progression. Interestingly, the major metabolic shift in metastatic cells is a large increase in the de novo synthesis of proline. This work provides the first comprehensive view of changes to central metabolism as a result of breast tumor progression. Electronic supplementary material The online version of this article (doi:10.1007/s10549-007-9732-3) contains supplementary material, which is available to authorized users. PMID:17879159

  5. The Central Carbon and Energy Metabolism of Marine Diatoms

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    Adriano Nunes-Nesi

    2013-05-01

    Full Text Available Diatoms are heterokont algae derived from a secondary symbiotic event in which a eukaryotic host cell acquired an eukaryotic red alga as plastid. The multiple endosymbiosis and horizontal gene transfer processes provide diatoms unusual opportunities for gene mixing to establish distinctive biosynthetic pathways and metabolic control structures. Diatoms are also known to have significant impact on global ecosystems as one of the most dominant phytoplankton species in the contemporary ocean. As such their metabolism and growth regulating factors have been of particular interest for many years. The publication of the genomic sequences of two independent species of diatoms and the advent of an enhanced experimental toolbox for molecular biological investigations have afforded far greater opportunities than were previously apparent for these species and re-invigorated studies regarding the central carbon metabolism of diatoms. In this review we discuss distinctive features of the central carbon metabolism of diatoms and its response to forthcoming environmental changes and recent advances facilitating the possibility of industrial use of diatoms for oil production. Although the operation and importance of several key pathways of diatom metabolism have already been demonstrated and determined, we will also highlight other potentially important pathways wherein this has yet to be achieved.

  6. Metabolic Flux Analysis of Shewanella spp. Reveals Evolutionary Robustness in Central Carbon Metabolism

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Yinjie J.; Martin, Hector Garcia; Dehal, Paramvir S.; Deutschbauer, Adam; Llora, Xavier; Meadows, Adam; Arkin, Adam; Keasling, Jay D.

    2009-08-19

    Shewanella spp. are a group of facultative anaerobic bacteria widely distributed in marine and fresh-water environments. In this study, we profiled the central metabolic fluxes of eight recently sequenced Shewanella species grown under the same condition in minimal med-ium with [3-13C] lactate. Although the tested Shewanella species had slightly different growth rates (0.23-0.29 h31) and produced different amounts of acetate and pyruvate during early exponential growth (pseudo-steady state), the relative intracellular metabolic flux distributions were remarkably similar. This result indicates that Shewanella species share similar regulation in regard to central carbon metabolic fluxes under steady growth conditions: the maintenance of metabolic robustness is not only evident in a single species under genetic perturbations (Fischer and Sauer, 2005; Nat Genet 37(6):636-640), but also observed through evolutionary related microbial species. This remarkable conservation of relative flux profiles through phylogenetic differences prompts us to introduce the concept of metabotype as an alternative scheme to classify microbial fluxomics. On the other hand, Shewanella spp. display flexibility in the relative flux profiles when switching their metabolism from consuming lactate to consuming pyruvate and acetate.

  7. Exhaustive Analysis of a Genotype Space Comprising 10(15 Central Carbon Metabolisms Reveals an Organization Conducive to Metabolic Innovation.

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    Sayed-Rzgar Hosseini

    2015-08-01

    Full Text Available All biological evolution takes place in a space of possible genotypes and their phenotypes. The structure of this space defines the evolutionary potential and limitations of an evolving system. Metabolism is one of the most ancient and fundamental evolving systems, sustaining life by extracting energy from extracellular nutrients. Here we study metabolism's potential for innovation by analyzing an exhaustive genotype-phenotype map for a space of 10(15 metabolisms that encodes all possible subsets of 51 reactions in central carbon metabolism. Using flux balance analysis, we predict the viability of these metabolisms on 10 different carbon sources which give rise to 1024 potential metabolic phenotypes. Although viable metabolisms with any one phenotype comprise a tiny fraction of genotype space, their absolute numbers exceed 10(9 for some phenotypes. Metabolisms with any one phenotype typically form a single network of genotypes that extends far or all the way through metabolic genotype space, where any two genotypes can be reached from each other through a series of single reaction changes. The minimal distance of genotype networks associated with different phenotypes is small, such that one can reach metabolisms with novel phenotypes--viable on new carbon sources--through one or few genotypic changes. Exceptions to these principles exist for those metabolisms whose complexity (number of reactions is close to the minimum needed for viability. Increasing metabolic complexity enhances the potential for both evolutionary conservation and evolutionary innovation.

  8. Recent advances in engineering the central carbon metabolism of industrially important bacteria

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    Papagianni Maria

    2012-04-01

    Full Text Available Abstract This paper gives an overview of the recent advances in engineering the central carbon metabolism of the industrially important bacteria Escherichia coli, Bacillus subtilis, Corynobacterium glutamicum, Streptomyces spp., Lactococcus lactis and other lactic acid bacteria. All of them are established producers of important classes of products, e.g. proteins, amino acids, organic acids, antibiotics, high-value metabolites for the food industry and also, promising producers of a large number of industrially or therapeutically important chemicals. Optimization of existing or introduction of new cellular processes in these microorganisms is often achieved through manipulation of targets that reside at major points of central metabolic pathways, such as glycolysis, gluconeogenesis, the pentose phosphate pathway and the tricarboxylic acid cycle with the glyoxylate shunt. Based on the huge progress made in recent years in biochemical, genetic and regulatory studies, new fascinating engineering approaches aim at ensuring an optimal carbon and energy flow within central metabolism in order to achieve optimized metabolite production.

  9. Zinc disrupts central carbon metabolism and capsule biosynthesis in Streptococcus pyogenes.

    Science.gov (United States)

    Ong, Cheryl-lynn Y; Walker, Mark J; McEwan, Alastair G

    2015-06-01

    Neutrophils release free zinc to eliminate the phagocytosed bacterial pathogen Streptococcus pyogenes (Group A Streptococcus; GAS). In this study, we investigated the mechanisms underpinning zinc toxicity towards this human pathogen, responsible for diseases ranging from pharyngitis and impetigo, to severe invasive infections. Using the globally-disseminated M1T1 GAS strain, we demonstrate that zinc stress impairs glucose metabolism through the inhibition of the glycolytic enzymes phosphofructokinase and glyceraldehyde-3-phosphate dehydrogenase. In the presence of zinc, a metabolic shift to the tagatose-6-phosphate pathway allows conversion of D-galactose to dihydroxyacetone phosphate and glyceraldehyde phosphate, partially bypassing impaired glycolytic enzymes to generate pyruvate. Additionally, zinc inhibition of phosphoglucomutase results in decreased capsule biosynthesis. These data indicate that zinc exerts it toxicity via mechanisms that inhibit both GAS central carbon metabolism and virulence pathways.

  10. A vector library for silencing central carbon metabolism genes with antisense RNAs in Escherichia coli.

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    Nakashima, Nobutaka; Ohno, Satoshi; Yoshikawa, Katsunori; Shimizu, Hiroshi; Tamura, Tomohiro

    2014-01-01

    We describe here the construction of a series of 71 vectors to silence central carbon metabolism genes in Escherichia coli. The vectors inducibly express antisense RNAs called paired-terminus antisense RNAs, which have a higher silencing efficacy than ordinary antisense RNAs. By measuring mRNA amounts, measuring activities of target proteins, or observing specific phenotypes, it was confirmed that all the vectors were able to silence the expression of target genes efficiently. Using this vector set, each of the central carbon metabolism genes was silenced individually, and the accumulation of metabolites was investigated. We were able to obtain accurate information on ways to increase the production of pyruvate, an industrially valuable compound, from the silencing results. Furthermore, the experimental results of pyruvate accumulation were compared to in silico predictions, and both sets of results were consistent. Compared to the gene disruption approach, the silencing approach has an advantage in that any E. coli strain can be used and multiple gene silencing is easily possible in any combination.

  11. Reliable Metabolic Flux Estimation in Escherichia coli Central Carbon Metabolism Using Intracellular Free Amino Acids

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    Nobuyuki Okahashi

    2014-05-01

    Full Text Available 13C metabolic flux analysis (MFA is a tool of metabolic engineering for investigation of in vivo flux distribution. A direct 13C enrichment analysis of intracellular free amino acids (FAAs is expected to reduce time for labeling experiments of the MFA. Measurable FAAs should, however, vary among the MFA experiments since the pool sizes of intracellular free metabolites depend on cellular metabolic conditions. In this study, minimal 13C enrichment data of FAAs was investigated to perform the FAAs-based MFA. An examination of a continuous culture of Escherichia coli using 13C-labeled glucose showed that the time required to reach an isotopically steady state for FAAs is rather faster than that for conventional method using proteinogenic amino acids (PAAs. Considering 95% confidence intervals, it was found that the metabolic flux distribution estimated using FAAs has a similar reliability to that of the PAAs-based method. The comparative analysis identified glutamate, aspartate, alanine and phenylalanine as the common amino acids observed in E. coli under different culture conditions. The results of MFA also demonstrated that the 13C enrichment data of the four amino acids is required for a reliable analysis of the flux distribution.

  12. Modeling the Contribution of Allosteric Regulation for Flux Control in the Central Carbon Metabolism of E. coli

    DEFF Research Database (Denmark)

    Machado, Daniel; Herrgard, Markus; Rocha, Isabel

    2015-01-01

    Modeling cellular metabolism is fundamental for many biotechnological applications, including drug discovery and rational cell factory design. Central carbon metabolism (CCM) is particularly important as it provides the energy and precursors for other biological processes. However, the complex...

  13. The Sinorhizobium meliloti RNA chaperone Hfq influences central carbon metabolism and the symbiotic interaction with alfalfa

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    Jiménez-Zurdo José I

    2010-03-01

    Full Text Available Abstract Background The bacterial Hfq protein is able to interact with diverse RNA molecules, including regulatory small non-coding RNAs (sRNAs, and thus it is recognized as a global post-transcriptional regulator of gene expression. Loss of Hfq has an extensive impact in bacterial physiology which in several animal pathogens influences virulence. Sinorhizobium meliloti is a model soil bacterium known for its ability to establish a beneficial nitrogen-fixing intracellular symbiosis with alfalfa. Despite the predicted general involvement of Hfq in the establishment of successful bacteria-eukaryote interactions, its function in S. meliloti has remained unexplored. Results Two independent S. meliloti mutants, 2011-3.4 and 1021Δhfq, were obtained by disruption and deletion of the hfq gene in the wild-type strains 2011 and 1021, respectively, both exhibiting similar growth defects as free-living bacteria. Transcriptomic profiling of 1021Δhfq revealed a general down-regulation of genes of sugar transporters and some enzymes of the central carbon metabolism, whereas transcripts specifying the uptake and metabolism of nitrogen sources (mainly amino acids were more abundant than in the wild-type strain. Proteomic analysis of the 2011-3.4 mutant independently confirmed these observations. Symbiotic tests showed that lack of Hfq led to a delayed nodulation, severely compromised bacterial competitiveness on alfalfa roots and impaired normal plant growth. Furthermore, a large proportion of nodules (55%-64% elicited by the 1021Δhfq mutant were non-fixing, with scarce content in bacteroids and signs of premature senescence of endosymbiotic bacteria. RT-PCR experiments on RNA from bacteria grown under aerobic and microoxic conditions revealed that Hfq contributes to regulation of nifA and fixK1/K2, the genes controlling nitrogen fixation, although the Hfq-mediated regulation of fixK is only aerobiosis dependent. Finally, we found that some of the recently

  14. Elementary Flux Mode Analysis Revealed Cyclization Pathway as a Powerful Way for NADPH Regeneration of Central Carbon Metabolism.

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    Bin Rui

    Full Text Available NADPH regeneration capacity is attracting growing research attention due to its important role in resisting oxidative stress. Besides, NADPH availability has been regarded as a limiting factor in production of industrially valuable compounds. The central carbon metabolism carries the carbon skeleton flux supporting the operation of NADPH-regenerating enzyme and offers flexibility in coping with NADPH demand for varied intracellular environment. To acquire an insightful understanding of its NADPH regeneration capacity, the elementary mode method was employed to compute all elementary flux modes (EFMs of a network representative of central carbon metabolism. Based on the metabolic flux distributions of these modes, a cluster analysis of EFMs with high NADPH regeneration rate was conducted using the self-organizing map clustering algorithm. The clustering results were used to study the relationship between the flux of total NADPH regeneration and the flux in each NADPH producing enzyme. The results identified several reaction combinations supporting high NADPH regeneration, which are proven to be feasible in cells via thermodynamic analysis and coincident with a great deal of previous experimental report. Meanwhile, the reaction combinations showed some common characteristics: there were one or two decarboxylation oxidation reactions in the combinations that produced NADPH and the combination constitution included certain gluconeogenesis pathways. These findings suggested cyclization pathways as a powerful way for NADPH regeneration capacity of bacterial central carbon metabolism.

  15. Reconstruction of central carbon metabolism in Sulfolobus solfataricus using a two-dimensional gel electrophoresis map, stable isotope labelling and DNA microarray analysis

    NARCIS (Netherlands)

    Snijders, B.P.L.; Walther, J.; Peter, S.; Kinnman, I.; Vos, de M.J.G.; Werken, van de H.J.G.; Brouns, S.J.J.; Oost, van der J.; Wright, P.C.

    2006-01-01

    In the last decade, an increasing number of sequenced archaeal genomes have become available, opening up the possibility for functional genomic analyses. Here, we reconstructed the central carbon metabolism in the hyperthermophilic crenarchaeon Sulfolobus solfataricus (glycolysis, gluconeogenesis an

  16. Modeling Central Carbon Metabolic Processes in Soil Microbial Communities: Comparing Measured With Modeled

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    Dijkstra, P.; Fairbanks, D.; Miller, E.; Salpas, E.; Hagerty, S.

    2013-12-01

    Understanding the mechanisms regulating C cycling is hindered by our inability to directly observe and measure the biochemical processes of glycolysis, pentose phosphate pathway, and TCA cycle in intact and complex microbial communities. Position-specific 13C labeled metabolic tracer probing is proposed as a new way to study microbial community energy production, biosynthesis, C use efficiency (the proportion of substrate incorporated into microbial biomass), and enables the quantification of C fluxes through the central C metabolic network processes (Dijkstra et al 2011a,b). We determined the 13CO2 production from U-13C, 1-13C, 2-13C, 3-13C, 4-13C, 5-13C, and 6-13C labeled glucose and 1-13C and 2,3-13C pyruvate in parallel incubations in three soils along an elevation gradient. Qualitative and quantitative interpretation of the results indicate a high pentose phosphate pathway activity in soils. Agreement between modeled and measured CO2 production rates for the six C-atoms of 13C-labeled glucose indicate that the metabolic model used is appropriate for soil community processes, but that improvements can be made. These labeling and modeling techniques may improve our ability to analyze the biochemistry and (eco)physiology of intact microbial communities. Dijkstra, P., Blankinship, J.C., Selmants, P.C., Hart, S.C., Koch, G.W., Schwartz, E., Hungate, B.A., 2011a. Probing C flux patterns of soil microbial metabolic networks using parallel position-specific tracer labeling. Soil Biology & Biochemistry 43, 126-132. Dijkstra, P., Dalder, J.J., Selmants, P.C., Hart, S.C., Koch, G.W., Schwartz, E., Hungate, B.A., 2011b. Modeling soil metabolic processes using isotopologue pairs of position-specific 13C-labeled glucose and pyruvate. Soil Biology & Biochemistry 43, 1848-1857.

  17. Use of Position-Specific 13C Isotopomers to Examine Central Carbon Metabolism in the Thermophile 'Thermoflexus hugenholtzii'

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    Thomas, S.; Tamadonfar, K. O.; Dijkstra, P.; Dodsworth, J. A.; Hedlund, B. P.

    2013-12-01

    'Thermoflexus hugenholtzii' is a member of a newly discovered class of Chloroflexi. It is the dominant microorganism in certain hot springs; however, very little is known about its physiology, and it is unable to grow on defined media. In order to examine central carbon metabolism in 'T. hugenholtzii', the genome was annotated for genes encoding enzymes for central carbon metabolism, revealing complete pathways for glycolysis, the tricarboxylic acid (TCA) cycle, and the pentose phosphate pathway (PPP). Isotope experiments were conducted to test predicted activities by adding position-specific carbon-13 (13C)-labeled metabolites of glucose, pyruvate, acetate, TCA metabolites, and amino acids and measuring the production of 13CO2 during exponential growth. Use of these metabolites demonstrated broad heterotrophic activity of 'T. hugenholtzii,' despite its inability to grow on defined media. Use of glucose-U demonstrated an active glycolytic pathway and pyruvate-1 demonstrated the functioning of the pyruvate oxidation pathway after glycolysis. Use of the TCA cycle intermediates citrate and succinate demonstrated an active TCA cycle. Production of CO2 from alanine and cysteine demonstrated oxidation of amino acids. However, lack of activity on glucose-1 failed to reveal an active PPP suggesting 'T. hugenholtzii' may rely on exogenous sources of pentoses for nucleic acid biosynthesis.

  18. Immunosuppressive activity enhances central carbon metabolism and bioenergetics in myeloid-derived suppressor cells in vitro models

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    Hammami Ines

    2012-07-01

    Full Text Available Abstract Background The tumor microenvironment contains a vast array of pro- and anti-inflammatory cytokines that alter myelopoiesis and lead to the maturation of immunosuppressive cells known as myeloid-derived suppressor cells (MDSCs. Incubating bone marrow (BM precursors with a combination of granulocyte-macrophage colony-stimulating factor (GM-CSF and interleukin-6 (IL-6 generated a tumor-infiltrating MDSC-like population that impaired anti-tumor specific T-cell functions. This in vitro experimental approach was used to simulate MDSC maturation, and the cellular metabolic response was then monitored. A complementary experimental model that inhibited L-arginine (L-Arg metabolizing enzymes in MSC-1 cells, an immortalized cell line derived from primary MDSCs, was used to study the metabolic events related to immunosuppression. Results Exposure of BM cells to GM-CSF and IL-6 activated, within 24 h, L-Arg metabolizing enzymes which are responsible for the MDSCs immunosuppressive potential. This was accompanied by an increased uptake of L-glutamine (L-Gln and glucose, the latter being metabolized by anaerobic glycolysis. The up-regulation of nutrient uptake lead to the accumulation of TCA cycle intermediates and lactate as well as the endogenous synthesis of L-Arg and the production of energy-rich nucleotides. Moreover, inhibition of L-Arg metabolism in MSC-1 cells down-regulated central carbon metabolism activity, including glycolysis, glutaminolysis and TCA cycle activity, and led to a deterioration of cell bioenergetic status. The simultaneous increase of cell specific concentrations of ATP and a decrease in ATP-to-ADP ratio in BM-derived MDSCs suggested cells were metabolically active during maturation. Moreover, AMP-activated protein kinase (AMPK was activated during MDSC maturation in GM-CSF and IL-6–treated cultures, as revealed by the continuous increase of AMP-to-ATP ratios and the phosphorylation of AMPK. Likewise, AMPK activity was

  19. Exhaustive analysis of a genotype space comprising 1015 central carbon metabolisms reveals an organization conducive to metabolic innovation

    OpenAIRE

    Hosseini, Sayed-Rzgar; Barve, Aditya; Wagner, Andreas

    2015-01-01

    All biological evolution takes place in a space of possible genotypes and their phenotypes. The structure of this space defines the evolutionary potential and limitations of an evolving system. Metabolism is one of the most ancient and fundamental evolving systems, sustaining life by extracting energy from extracellular nutrients. Here we study metabolism's potential for innovation by analyzing an exhaustive genotype-phenotype map for a space of 10(15) metabolisms that encodes all possible su...

  20. Exhaustive Analysis of a Genotype Space Comprising 10(15 )Central Carbon Metabolisms Reveals an Organization Conducive to Metabolic Innovation.

    OpenAIRE

    Sayed-Rzgar Hosseini; Aditya Barve; Andreas Wagner

    2015-01-01

    All biological evolution takes place in a space of possible genotypes and their phenotypes. The structure of this space defines the evolutionary potential and limitations of an evolving system. Metabolism is one of the most ancient and fundamental evolving systems, sustaining life by extracting energy from extracellular nutrients. Here we study metabolism's potential for innovation by analyzing an exhaustive genotype-phenotype map for a space of 10(15) metabolisms that encodes all possible su...

  1. Genetic analysis of central carbon metabolism unveils an amino acid substitution that alters maize NAD-dependent isocitrate dehydrogenase activity.

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    Nengyi Zhang

    Full Text Available BACKGROUND: Central carbon metabolism (CCM is a fundamental component of life. The participating genes and enzymes are thought to be structurally and functionally conserved across and within species. Association mapping utilizes a rich history of mutation and recombination to achieve high resolution mapping. Therefore, applying association mapping in maize (Zea mays ssp. mays, the most diverse model crop species, to study the genetics of CCM is a particularly attractive system. METHODOLOGY/PRINCIPAL FINDINGS: We used a maize diversity panel to test the CCM functional conservation. We found heritable variation in enzyme activity for every enzyme tested. One of these enzymes was the NAD-dependent isocitrate dehydrogenase (IDH, E.C. 1.1.1.41, in which we identified a novel amino-acid substitution in a phylogenetically conserved site. Using candidate gene association mapping, we identified that this non-synonymous polymorphism was associated with IDH activity variation. The proposed mechanism for the IDH activity variation includes additional components regulating protein level. With the comparison of sequences from maize and teosinte (Zea mays ssp. Parviglumis, the maize wild ancestor, we found that some CCM genes had also been targeted for selection during maize domestication. CONCLUSIONS/SIGNIFICANCE: Our results demonstrate the efficacy of association mapping for dissecting natural variation in primary metabolic pathways. The considerable genetic diversity observed in maize CCM genes underlies heritable phenotypic variation in enzyme activities and can be useful to identify putative functional sites.

  2. Control of Proteobacterial Central Carbon Metabolism by the HexR Transcriptional Regulator. A Case Study in Shewanella oneidensis

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    Leyn, Semen; Li, Xiaoqing; Zheng, Qijing; Novichkov, Pavel; Reed, Samantha B.; Romine, Margaret F.; Fredrickson, Jim K.; Yang, Chen; Osterman, Andrei L.; Rodionov, Dmitry A.

    2011-08-17

    Bacteria exploit multiple mechanisms for controlling central carbon metabolism (CCM). Thus, a bioinformatic analysis together with some experimental data implicated HexR transcriptional factor as a global CCM regulator in some lineages of Gammaproteobacteria operating as a functional replacement of Cra regulator characteristic of Enterobacteriales. In this study we combined a large-scale comparative genomic reconstruction of HexRcontrolled regulons in 87 species of Proteobacteria with the detailed experimental analysis of HexR regulatory network in Shewanella oneidensis model system. Although nearly all of the HexR-controlled genes are associated with CCM, remarkable variations were revealed in the scale (from 1-2 target operons in Enterobacteriales up to 20 operons in Aeromonadales) and gene content of HexR regulons between 11 compared lineages. A predicted 17-bp pseudo-palindrome with a consensus tTGTAATwwwATTACa, was confirmed as HexR-binding motif for 15 target operons (comprising 30 genes) by in vitro binding assays. The negative effect of the key CCM intermediate, 2-keto-3-deoxy-6- phosphogluconate, on the DNA-regulator complex formation was verified. A dual mode of HexR action on various target promoters, repression of genes involved in catabolic pathways and activation of gluconeogenic genes, was for the first time predicted by the bioinformatc analysis and experimentally verified by changed gene expression pattern in S. oneidensis AhexR mutant. Phenotypic profiling revealed the inability of this mutant to grow on lactate or pyruvate as a single carbon source. A comparative metabolic flux analysis of wild-type and mutant strains of S. oneidensis using 13Clactate labeling and GC-MS analysis confirmed the hypothesized HexR role as a master regulator of gluconeogenic flux from pyruvate via the transcriptional activation of phosphoenolpyruvate synthase (PpsA).

  3. The carbon storage regulator (Csr) system exerts a nutrient-specific control over central metabolism in Escherichia coli strain Nissle 1917.

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    Revelles, Olga; Millard, Pierre; Nougayrède, Jean-Philippe; Dobrindt, Ulrich; Oswald, Eric; Létisse, Fabien; Portais, Jean-Charles

    2013-01-01

    The role of the post-transcriptional carbon storage regulator (Csr) system in nutrient utilization and in the control of the central metabolism in E. coli reference commensal strain Nissle 1917 was investigated. Analysis of the growth capabilities of mutants altered for various components of the Csr system (csrA51, csrB, csrC and csrD mutations) showed that only the protein CsrA - the key component of the system - exerts a marked role in carbon nutrition. Attenuation of CsrA activity in the csrA51 mutant affects the growth efficiency on a broad range of physiologically relevant carbon sources, including compounds utilized by the Entner-Doudoroff (ED) pathway. Detailed investigations of the metabolomes and fluxomes of mutants and wild-type cells grown on carbon sources representative of glycolysis and of the ED pathway (glucose and gluconate, respectively), revealed significant re-adjusting of central carbon metabolism for both compounds in the csrA51 mutant. However, the metabolic re-adjusting observed on gluconate was strikingly different from that observed on glucose, indicating a nutrient-specific control of metabolism by the Csr system. PMID:23840455

  4. The redox-sensing regulator Rex modulates central carbon metabolism, stress tolerance response and biofilm formation by Streptococcus mutans.

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    Jacob P Bitoun

    Full Text Available The Rex repressor has been implicated in regulation of central carbon and energy metabolism in gram-positive bacteria. We have previously shown that Streptococcus mutans, the primary causative agent of dental caries, alters its transcriptome upon Rex-deficiency and renders S. mutans to have increased susceptibility to oxidative stress, aberrations in glucan production, and poor biofilm formation. In this study, we showed that rex in S. mutans is co-transcribed as an operon with downstream guaA, encoding a putative glutamine amidotransferase. Electrophoretic mobility shift assays showed that recombinant Rex bound promoters of target genes avidly and specifically, including those down-regulated in response to Rex-deficiency, and that the ability of recombinant Rex to bind to selected promoters was modulated by NADH and NAD(+. Results suggest that Rex in S. mutans can function as an activator in response to intracellular NADH/NAD(+ level, although the exact binding site for activator Rex remains unclear. Consistent with a role in oxidative stress tolerance, hydrogen peroxide challenge assays showed that the Rex-deficient mutant, TW239, and the Rex/GuaA double mutant, JB314, were more susceptible to hydrogen peroxide killing than the wildtype, UA159. Relative to UA159, JB314 displayed major defects in biofilm formation, with a decrease of more than 50-fold in biomass after 48-hours. Collectively, these results further suggest that Rex in S. mutans regulates fermentation pathways, oxidative stress tolerance, and biofilm formation in response to intracellular NADH/NAD(+ level. Current effort is being directed to further investigation of the role of GuaA in S. mutans cellular physiology.

  5. Investigating the effects of perturbations to pgi and eno gene expression on central carbon metabolism in Escherichia coli using 13 C metabolic flux analysis

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    Usui Yuki

    2012-06-01

    Full Text Available Abstract Background It has long been recognized that analyzing the behaviour of the complex intracellular biological networks is important for breeding industrially useful microorganisms. However, because of the complexity of these biological networks, it is currently not possible to obtain all the desired microorganisms. In this study, we constructed a system for analyzing the effect of gene expression perturbations on the behavior of biological networks in Escherichia coli. Specifically, we utilized 13 C metabolic flux analysis (13 C-MFA to analyze the effect of perturbations to the expression levels of pgi and eno genes encoding phosphoglucose isomerase and enolase, respectively on metabolic fluxes. Results We constructed gene expression-controllable E. coli strains using a single-copy mini F plasmid. Using the pgi expression-controllable strain, we found that the specific growth rate correlated with the pgi expression level. 13 C-MFA of this strain revealed that the fluxes for the pentose phosphate pathway and Entner-Doudoroff pathway decreased, as the pgi expression lelvel increased. In addition, the glyoxylate shunt became active when the pgi expression level was almost zero. Moreover, the flux for the glyoxylate shunt increased when the pgi expression level decreased, but was significantly reduced in the pgi-knockout cells. Comparatively, eno expression could not be decreased compared to the parent strain, but we found that increased eno expression resulted in a decreased specific growth rate. 13 C-MFA revealed that the metabolic flux distribution was not altered by an increased eno expression level, but the overall metabolic activity of the central metabolism decreased. Furthermore, to evaluate the impact of perturbed expression of pgi and eno genes on changes in metabolic fluxes in E. coli quantitatively, metabolic sensitivity analysis was performed. As a result, the perturbed expression of pgi gene had a great impact to the

  6. A fuzzy logic controller based approach to model the switching mechanism of the mammalian central carbon metabolic pathway in normal and cancer cells.

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    Dasgupta, Abhijit; Paul, Debjyoti; De, Rajat K

    2016-07-19

    Dynamics of large nonlinear complex systems, like metabolic networks, depend on several parameters. A metabolic pathway may switch to another pathway in accordance with the current state of parameters in both normal and cancer cells. Here, most of the parameter values are unknown to us. A fuzzy logic controller (FLC) has been developed here for the purpose of modeling metabolic networks by approximating the reasons for the behaviour of a system and applying expert knowledge to track switching between metabolic pathways. The simulation results can track the switching between glycolysis and gluconeogenesis, as well as glycolysis and pentose phosphate pathways (PPP) in normal cells. Unlike normal cells, pyruvate kinase (M2 isoform) (PKM2) switches alternatively between its two oligomeric forms, i.e. an active tetramer and a relatively low activity dimer, in cancer cells. Besides, there is a coordination among PKM2 switching and enzymes catalyzing PPP. These phenomena help cancer cells to maintain their high energy demand and macromolecular synthesis. However, the reduction of initial adenosine triphosphate (ATP) to a very low concentration, decreasing initial glucose uptake, destroying coordination between glycolysis and PPP, and replacement of PKM2 by its relatively inactive oligomeric form (dimer) or inhibition of the translation of PKM2 may destabilize the mutated control mechanism of the mammalian central carbon metabolic (CCM) pathway in cancer cells. The performance of the model is compared appropriately with some existing ones. PMID:27225801

  7. Crassulacean acid metabolism (CAM) in leaves of Aloe arborescens mill : Comparative studies of the carbon metabolism of chlorenchym and central hydrenchym.

    Science.gov (United States)

    Kluge, M; Knapp, I; Kramer, D; Schwerdtner, I; Ritter, H

    1979-01-01

    In the succulent leaves of Aloe arborescens Mill diurnal oscillations of the malic acid content, being indicative of Crassulacean Acid Metabolism (CAM), were exhibited only by the green mesophyll. In contrast, the malic acid level of the central chloroplast-free water-storing tissue remained constant throughout the day-night cycle. Apart from malate, the green tissue contained high amounts of isocitrat which was lacking in the water tissue. There was no significant transfer from the green mesophyll to the water tissue of (14)C fixed originally via dark (14)CO2 fixation in the mesophyll. Both isolated mesophyll and water tissue were capable of dark CO2 fixation yielding mainly malate as the first stable product. Both tissues have phosphoenolpyruvate carboxylase. However, the enzymes derived from the both sources could be distinguished by their molecular weights and by their kinetic properties, suggesting different phosphoenolpyruvate carboxylase proteins. The conclusion drawn from the experiments is that in a. arborescens the CAM cycle proceeds exclusively in the green mesophyll and that the water tissue, though capable of malate synthesis via β-carboxylation of phosphoenolpyruvate, behaves as an independent metabolic system where CAM is lacking. This view is supported by the finding that the cell walls bordering the green mesophyll from the water tissue lack plasmodesmata, hence conveniant pathways of metabolite transport. PMID:24317763

  8. Metabolic syndrome and central retinal artery occlusion

    Directory of Open Access Journals (Sweden)

    Kosanović-Jaković Natalija

    2005-01-01

    Full Text Available Background. The accumulation of risk factors for central retinal artery occlusion can be seen in a single person and might be explained by the metabolic syndrome. Case report. We presented the case of a 52-year-old man with no light perception in his right eye. The visual loss was monocular and painless, fundoscopy showed central retinal artery occlusion and the laboratory investigation showed the raised erythrocyte sedimentation rate of 105 mm/h and the raised C-reactive protein of 22 mg/l. Specific laboratory investigations and fluorescein angiography excluded the presence of vasculitis, collagen vascular diseases, hypercoagulable state and antiphospholipid syndrome. Conclusion. The patient met all the five of the National Cholesterol Education Program (NCEP criteria for the metabolic syndrome: hypertension, abnormal lipid profile, abnormal glucose metabolism, obesity and hyperuricemia. Measurement of C-reactive protein is useful for the assessment of therapeutic systemic effect on any abnormality in the metabolic syndrome. Individual therapy for all risk factors in the metabolic syndrome is necessary to prevent complications such as cardiovascular, retinal vascular diseases and stroke.

  9. Metabolic syndrome and central retinal artery occlusion

    OpenAIRE

    Kosanović-Jaković Natalija; Petrović Lidija; Risimić Dijana; Milenković Svetislav; Matić Danica

    2005-01-01

    Background. The accumulation of risk factors for central retinal artery occlusion can be seen in a single person and might be explained by the metabolic syndrome. Case report. We presented the case of a 52-year-old man with no light perception in his right eye. The visual loss was monocular and painless, fundoscopy showed central retinal artery occlusion and the laboratory investigation showed the raised erythrocyte sedimentation rate of 105 mm/h and the raised C-reactive protein of 22 mg/l. ...

  10. Effects of Conservation Tillage on Topsoil Microbial Metabolic Characteristics and Organic Carbon within Aggregates under a Rice (Oryza sativa L.-Wheat (Triticum aestivum L. Cropping System in Central China.

    Directory of Open Access Journals (Sweden)

    Li-Jin Guo

    Full Text Available Investigating microbial metabolic characteristics and soil organic carbon (SOC within aggregates and their relationships under conservation tillage may be useful in revealing the mechanism of SOC sequestration in conservation tillage systems. However, limited studies have been conducted to investigate the relationship between SOC and microbial metabolic characteristics within aggregate fractions under conservation tillage. We hypothesized that close relationships can exist between SOC and microbial metabolic characteristics within aggregates under conservation tillage. In this study, a field experiment was conducted from June 2011 to June 2013 following a split-plot design of a randomized complete block with tillage practices [conventional intensive tillage (CT and no tillage (NT] as main plots and straw returning methods [preceding crop residue returning (S, 2100-2500 kg C ha-1 and removal (NS, 0 kg C ha(-1] as subplots with three replications. The objective of this study was to reveal the effects of tillage practices and residue-returning methods on topsoil microbial metabolic characteristics and organic carbon (SOC fractions within aggregates and their relationships under a rice-wheat cropping system in central China. Microbial metabolic characteristics investigated using the Biolog system was examined within two aggregate fractions (>0.25 and 0.25 aggregate, and 0.25 mm aggregate (11.3%, and 0.25 mm aggregate, and 0.25 mm aggregate, and 0.25 and 0.25 mm aggregate in the upper (0-5 cm soil layer under conservation tillage systems, as well as directly and indirectly by promoting DOC and MBC in <0.25 mm aggregate. Our results suggested that conservation tillage increased SOC in aggregates in the topsoil by improving microbial metabolic activities.

  11. Photosynthetic carbon monoxide metabolism by sugarcane leaves

    Energy Technology Data Exchange (ETDEWEB)

    Kortschak, H.P.; Nickell, L.G.

    1973-01-01

    The photosynthetic carbon monoxide metabolism by sugarcane was studied to determine whether substantial quantities of CO are removed from the air by fields in Hawaii. Leaves metabolized low CO concentrations photosynthetically, with sucrose as an end product. Rates of uptake were of the order of 10/sup -4/ power mg/d sq m/hr. This was to low to be significant in removing CO from the atmosphere.

  12. Central nervous system control of triglyceride metabolism

    NARCIS (Netherlands)

    Geerling, Johanna Janetta (Janine)

    2013-01-01

    This thesis describes the role of the brain in the regulation of peripheral triglyceride metabolism, in the context of the metabolic syndrome. Based on various pharmacological studies we described the role of two hormones, insulin and glucagon-like peptide-1, in the production and clearance of trigl

  13. Central Metabolic Pathways of Hyperthermophiles: Important Clues on how Metabolism Gives Rise to Life

    Science.gov (United States)

    Ronimus, R. S.; Morgan, H. W.

    2004-06-01

    Vital clues on life's origins within the galaxy exist here on present day Earth. Life is currently divided into the three domains Bacteria, Archaea and Eukarya based on the phylogeny of small ribosomal subunit RNA (16S/18S) gene sequences. The domains are presumed to share a ``last universal common ancestor'' (LUCA). Hyperthermophilic bacteria and archaea, which are able to thrive at 80^{circ}C or higher, dominate the bottom of the tree of life and are thus suggested to be the least evolved, or most ``ancient''. Geochemical data indicates that life first appeared on Earth approximately 3.8 billion years ago in a hot environment. Due to these considerations, hyperthermophiles represent the most appropriate microorganisms to investigate the origins of metabolism. The central biochemical pathway of gluconeogenesis/glycolysis (the Embden-Meyerhof pathway) which produces six carbon sugars from three carbon compounds is present in all organisms and can provide important hints concerning the early development of metabolism. Significantly, there are a number of striking deviations from the textbook canonical reaction sequence that are found, particularly in hyperthermophilic archaea. In this paper the phylogenetic istribution of enzymes of the pathway is detailed; overall, the distribution pattern provides strong evidence for the pathway to have developed from the bottom-up.

  14. Modelling central metabolic fluxes by constraint-based optimization reveals metabolic reprogramming of developing Solanum lycopersicum (tomato) fruit.

    Science.gov (United States)

    Colombié, Sophie; Nazaret, Christine; Bénard, Camille; Biais, Benoît; Mengin, Virginie; Solé, Marion; Fouillen, Laëtitia; Dieuaide-Noubhani, Martine; Mazat, Jean-Pierre; Beauvoit, Bertrand; Gibon, Yves

    2015-01-01

    Modelling of metabolic networks is a powerful tool to analyse the behaviour of developing plant organs, including fruits. Guided by our current understanding of heterotrophic metabolism of plant cells, a medium-scale stoichiometric model, including the balance of co-factors and energy, was constructed in order to describe metabolic shifts that occur through the nine sequential stages of Solanum lycopersicum (tomato) fruit development. The measured concentrations of the main biomass components and the accumulated metabolites in the pericarp, determined at each stage, were fitted in order to calculate, by derivation, the corresponding external fluxes. They were used as constraints to solve the model by minimizing the internal fluxes. The distribution of the calculated fluxes of central metabolism were then analysed and compared with known metabolic behaviours. For instance, the partition of the main metabolic pathways (glycolysis, pentose phosphate pathway, etc.) was relevant throughout fruit development. We also predicted a valid import of carbon and nitrogen by the fruit, as well as a consistent CO2 release. Interestingly, the energetic balance indicates that excess ATP is dissipated just before the onset of ripening, supporting the concept of the climacteric crisis. Finally, the apparent contradiction between calculated fluxes with low values compared with measured enzyme capacities suggest a complex reprogramming of the metabolic machinery during fruit development. With a powerful set of experimental data and an accurate definition of the metabolic system, this work provides important insight into the metabolic and physiological requirements of the developing tomato fruits.

  15. Carbon metabolic pathways in phototrophic bacteria and their broader evolutionary implications

    Directory of Open Access Journals (Sweden)

    Kuo-Hsiang eTang

    2011-08-01

    Full Text Available Photosynthesis is the biological process that converts solar energy to biomass, bio-products and biofuel. It is the only major natural solar energy storage mechanism on Earth. To satisfy the increased demand for sustainable energy sources and identify the mechanism of photosynthetic carbon assimilation, which is one of the bottlenecks in photosynthesis, it is essential to understand the process of solar energy storage and associated carbon metabolism in photosynthetic organisms. Researchers have employed physiological studies, microbiological chemistry, enzyme assays, genome sequencing, transcriptomics, and 13C-based metabolomics/fluxomics to investigate central carbon metabolism and enzymes that operate in phototrophs. In this report, we review diverse CO2 assimilation pathways, acetate assimilation, carbohydrate catabolism, the TCA cycle and some key and/or unconventional enzymes in central carbon metabolism of phototrophic microorganisms. We also discuss the reducing equivalent flow during photoautotrophic and photoheterotrophic growth, evolutionary links in the central carbon metabolic network, and correlations between photosynthetic and non-photosynthetic organisms. Considering the metabolic versatility in these fascinating and diverse photosynthetic bacteria, many essential questions in their central carbon metabolism still remain to be addressed.

  16. Evaluating Soil Carbon Sequestration in Central Iowa

    Science.gov (United States)

    Doraiswamy, P. C.; Hunt, E. R.; McCarty, G. W.; Daughtry, C. S.; Izaurralde, C.

    2005-12-01

    The potential for reducing atmospheric carbon dioxide (CO2) concentration through landuse and management of agricultural systems is of great interest worldwide. Agricultural soils can be a source of CO2 when not properly managed but can also be a sink for sequestering CO2 through proper soil and crop management. The EPIC-CENTURY biogeochemical model was used to simulate the baseline level of soil carbon from soil survey data and project changes in soil organic carbon (SOC) under different tillage and crop management practices for corn and soybean crops. The study was conducted in central Iowa (50 km x 100 km) to simulate changes in soil carbon over the next 50 years. The simulations were conducted in two phases; initially a 25-year period (1971-1995) was simulated using conventional tillage practices since there was a transition in new management after 1995. In the second 25-year period (1996-2020), four different modeling scenarios were applied namely; conventional tillage, mulch tillage, no-tillage and no-tillage with a rye cover crop over the winter. The model simulation results showed potential gains in soil carbon in the top layers of the soil for conservation tillage. The simulations were made at a spatial resolution of 1.6 km x 1.6 km and mapped for the study area. There was a mean reduction in soil organic carbon of 0.095 T/ha per year over the 25-year period starting with 1996 for the conventional tillage practice. However, for management practices of mulch tillage, no tillage and no tillage with cover crop there was an increase in soil organic carbon of 0.12, 0.202 and 0.263 T/ha respectively over the same 25-year period. These results are in general similar to studies conducted in this region.

  17. A central role of abscisic acid in stress-regulated carbohydrate metabolism.

    Directory of Open Access Journals (Sweden)

    Stefan Kempa

    Full Text Available BACKGROUND: Abiotic stresses adversely affect plant growth and development. The hormone abscisic acid (ABA plays a central role in the response and adaptation to environmental constraints. However, apart from the well established role of ABA in regulating gene expression programmes, little is known about its function in plant stress metabolism. PRINCIPAL FINDINGS: Using an integrative multiparallel approach of metabolome and transcriptome analyses, we studied the dynamic response of the model glyophyte Arabidopsis thaliana to ABA and high salt conditions. Our work shows that salt stress induces complex re-adjustment of carbohydrate metabolism and that ABA triggers the initial steps of carbon mobilisation. SIGNIFICANCE: These findings open new perspectives on how high salinity and ABA impact on central carbohydrate metabolism and highlight the power of iterative combinatorial approaches of non-targeted and hypothesis-driven experiments in stress biology.

  18. Metabolic carbon fluxes and biosynthesis of polyhydroxyalkanoates in Ralstonia eutropha on short chain fatty acids.

    Science.gov (United States)

    Yu, Jian; Si, Yingtao

    2004-01-01

    Short chain fatty acids such as acetic, propionic, and butyric acids can be synthesized into polyhydroxyalkanoates (PHAs) by Ralstonia eutropha. Metabolic carbon fluxes of the acids in living cells have significant effect on the yield, composition, and thermomechanical properties of PHA bioplastics. Based on the general knowledge of central metabolism pathways and the unusual metabolic pathways in R. eutropha, a metabolic network of 41 bioreactions is constructed to analyze the carbon fluxes on utilization of the short chain fatty acids. In fed-batch cultures with constant feeding of acid media, carbon metabolism and distribution in R. eutropha were measured involving CO2, PHA biopolymers, and residual cell mass. As the cells underwent unsteady state metabolism and PHA biosynthesis under nitrogen-limited conditions, accumulative carbon balance was applied for pseudo-steady-state analysis of the metabolic carbon fluxes. Cofactor NADP/NADPH balanced between PHA synthesis and the C3/C4 pathway provided an independent constraint for solution of the underdetermined metabolic network. A major portion of propionyl-CoA was directed to pyruvate via the 2-methylcitrate cycle and further decarboxylated to acetyl-CoA. Only a small amount of propionate carbon (acetic acid in the medium. Malate is the node of the C3/C4 pathway and TCA cycle and its decarboxylation to dehydrogenation ranges from 0.33 to 1.28 in response to the demands on NADPH and oxaloacetate for short chain fatty acids utilization. PMID:15296425

  19. Flux analysis of central metabolic pathways in Geobactermetallireducens during reduction of solubleFe(III)-NTA

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Yinjie J.; Chakraborty, Romy; Garcia-Martin, Hector; Chu,Jeannie; Hazen, Terry C.; Keasling, Jay D.

    2007-01-01

    We analyzed the carbon fluxes in the central metabolism ofGeobacter metallireducens strain GS-15 using 13C isotopomer modeling.Acetate labeled in the 1st or 2nd position was the sole carbon source,and Fe-NTA was the sole terminal electron acceptor. The measured labeledacetate uptake rate was 21 mmol/gdw/h in the exponential growth phase.The resulting isotope labeling pattern of amino acids allowed an accuratedetermination of the in vivo global metabolic reaction rates (fluxes)through the central metabolic pathways using a computational isotopomermodel. The tracer experiments showed that G. metallireducens containedcomplete biosynthesis pathways for essential metabolism, and this strainmight also have an unusual isoleucine biosynthesis route (usingacetyl-CoA and pyruvate as the precursors). The model indicated that over90 percent of the acetate was completely oxidized to CO2 via a completetricarboxylic acid (TCA) cycle while reducing iron. Pyruvate carboxylaseand phosphoenolpyruvate carboxykinase were present under theseconditions, but enzymes in the glyoxylate shunt and malic enzyme wereabsent. Gluconeogenesis and the pentose phosphate pathway were mainlyemployed for biosynthesis and accounted for less than 3 percent of totalcarbon consumption. The model also indicated surprisingly highreversibility in the reaction between oxoglutarate and succinate. Thisstep operates close to the thermodynamic equilibrium possibly becausesuccinate is synthesized via a transferase reaction, and the conversionof oxoglutarate to succinate is a rate limiting step for carbonmetabolism. These findings enable a better understanding of therelationship between genome annotation and extant metabolic pathways inG. metallireducens.

  20. Staphylococcus aureus small colony variants show common metabolic features in central metabolism irrespective of the underlying auxotrophism

    Directory of Open Access Journals (Sweden)

    André eKriegeskorte

    2014-10-01

    Full Text Available In addition to the classical phenotype, Staphylococcus aureus may exhibit the small colony-variant (SCV phenotype, which has been associated with chronic, persistent and/or relapsing infections. SCVs are characterized by common phenotypic features such as slow growth, altered susceptibility to antibiotic agents and pathogenic traits based on increased internalization and intracellular persistence. They show frequently auxotrophiesms mainly based on two different mechanisms: (i deficiencies in electron transport as shown for menadione- and/or hemin-auxotrophs and (ii thymidylate biosynthetic-defective SCVs. To get a comprehensive overview of the metabolic differences between both phenotypes, we compared sets of clinically derived menadione-, hemin- and thymidine-auxotrophic SCVs and stable site directed mutants exhibiting the SCV phenotype with their corresponding isogenic parental strains displaying the normal phenotype. Isotopologue profiling and transcriptional analysis of central genes involved in carbon metabolism, revealed large differences between both phenotypes. Labeling experiments with [U-13C6]glucose showed reduced 13C incorporation into aspartate and glutamate from all SCVs irrespective of the underlying auxotrophism. More specifically, these SCVs showed decreased fractions of 13C2-aspartate and glutamate; 13C3-glutamate was not detected at all in the SCVs. In comparison to the patterns in the corresponding experiment with the classical S. aureus phenotype, this indicated a reduced carbon flux via the citric acid cycle in all SCV phenotypes. Indeed, the aconitase-encoding gene (acnA was found down-regulated in all SCV phenotypes under study. In conclusion, all SCV phenotypes including clinical isolates and site-directed mutants displaying the SCV phenotype were characterized by down-regulation of citric acid cycle activity. The common metabolic features in central carbon metabolism found in all SCVs may explain similar

  1. Tuning fresh: radiation through rewiring of central metabolism in streamlined bacteria

    Science.gov (United States)

    Eiler, Alexander; Mondav, Rhiannon; Sinclair, Lucas; Fernandez-Vidal, Leyden; Scofield, Douglas G; Schwientek, Patrick; Martinez-Garcia, Manuel; Torrents, David; McMahon, Katherine D; Andersson, Siv GE; Stepanauskas, Ramunas; Woyke, Tanja; Bertilsson, Stefan

    2016-01-01

    Most free-living planktonic cells are streamlined and in spite of their limitations in functional flexibility, their vast populations have radiated into a wide range of aquatic habitats. Here we compared the metabolic potential of subgroups in the Alphaproteobacteria lineage SAR11 adapted to marine and freshwater habitats. Our results suggest that the successful leap from marine to freshwaters in SAR11 was accompanied by a loss of several carbon degradation pathways and a rewiring of the central metabolism. Examples for these are C1 and methylated compounds degradation pathways, the Entner–Doudouroff pathway, the glyoxylate shunt and anapleuretic carbon fixation being absent from the freshwater genomes. Evolutionary reconstructions further suggest that the metabolic modules making up these important freshwater metabolic traits were already present in the gene pool of ancestral marine SAR11 populations. The loss of the glyoxylate shunt had already occurred in the common ancestor of the freshwater subgroup and its closest marine relatives, suggesting that the adaptation to freshwater was a gradual process. Furthermore, our results indicate rapid evolution of TRAP transporters in the freshwater clade involved in the uptake of low molecular weight carboxylic acids. We propose that such gradual tuning of metabolic pathways and transporters toward locally available organic substrates is linked to the formation of subgroups within the SAR11 clade and that this process was critical for the freshwater clade to find and fix an adaptive phenotype. PMID:26784354

  2. Integrating Kinetic Model of E. coli with Genome Scale Metabolic Fluxes Overcomes Its Open System Problem and Reveals Bistability in Central Metabolism.

    Directory of Open Access Journals (Sweden)

    Ahmad A Mannan

    Full Text Available An understanding of the dynamics of the metabolic profile of a bacterial cell is sought from a dynamical systems analysis of kinetic models. This modelling formalism relies on a deterministic mathematical description of enzyme kinetics and their metabolite regulation. However, it is severely impeded by the lack of available kinetic information, limiting the size of the system that can be modelled. Furthermore, the subsystem of the metabolic network whose dynamics can be modelled is faced with three problems: how to parameterize the model with mostly incomplete steady state data, how to close what is now an inherently open system, and how to account for the impact on growth. In this study we address these challenges of kinetic modelling by capitalizing on multi-'omics' steady state data and a genome-scale metabolic network model. We use these to generate parameters that integrate knowledge embedded in the genome-scale metabolic network model, into the most comprehensive kinetic model of the central carbon metabolism of E. coli realized to date. As an application, we performed a dynamical systems analysis of the resulting enriched model. This revealed bistability of the central carbon metabolism and thus its potential to express two distinct metabolic states. Furthermore, since our model-informing technique ensures both stable states are constrained by the same thermodynamically feasible steady state growth rate, the ensuing bistability represents a temporal coexistence of the two states, and by extension, reveals the emergence of a phenotypically heterogeneous population.

  3. New insights into Escherichia coli metabolism: carbon scavenging, acetate metabolism and carbon recycling responses during growth on glycerol

    Directory of Open Access Journals (Sweden)

    Martínez-Gómez Karla

    2012-07-01

    Full Text Available Abstract Background Glycerol has enhanced its biotechnological importance since it is a byproduct of biodiesel synthesis. A study of Escherichia coli physiology during growth on glycerol was performed combining transcriptional-proteomic analysis as well as kinetic and stoichiometric evaluations in the strain JM101 and certain derivatives with important inactivated genes. Results Transcriptional and proteomic analysis of metabolic central genes of strain JM101 growing on glycerol, revealed important changes not only in the synthesis of MglB, LamB and MalE proteins, but also in the overexpression of carbon scavenging genes: lamB, malE, mglB, mglC, galP and glk and some members of the RpoS regulon (pfkA, pfkB, fbaA, fbaB, pgi, poxB, acs, actP and acnA. Inactivation of rpoS had an important effect on stoichiometric parameters and growth adaptation on glycerol. The observed overexpression of poxB, pta, acs genes, glyoxylate shunt genes (aceA, aceB, glcB and glcC and actP, suggested a possible carbon flux deviation into the PoxB, Acs and glyoxylate shunt. In this scenario acetate synthesized from pyruvate with PoxB was apparently reutilized via Acs and the glyoxylate shunt enzymes. In agreement, no acetate was detected when growing on glycerol, this strain was also capable of glycerol and acetate coutilization when growing in mineral media and derivatives carrying inactivated poxB or pckA genes, accumulated acetate. Tryptophanase A (TnaA was synthesized at high levels and indole was produced by this enzyme, in strain JM101 growing on glycerol. Additionally, in the isogenic derivative with the inactivated tnaA gene, no indole was detected and acetate and lactate were accumulated. A high efficiency aromatic compounds production capability was detected in JM101 carrying pJLBaroGfbrtktA, when growing on glycerol, as compared to glucose. Conclusions The overexpression of several carbon scavenging, acetate metabolism genes and the absence of acetate

  4. Engineering Plant One-Carbon Metabolism

    Energy Technology Data Exchange (ETDEWEB)

    David Rhodes

    2005-02-09

    Primary and secondary metabolism intersect in the one-carbon (C1) area. Primary metabolism supplies most of the C1 units and competes with secondary metabolism for their use. This competition is potentially severe because secondary products such as lignin, alkaloids, and glycine betaine (GlyBet) require massive amounts of C1 units. Towards the goal of understanding how C1 metabolism is regulated at the metabolic and gene levels so as to successfully engineer C1 supply to match demand, we have: (1) cloned complete suites of C1 genes from maize and tobacco, and incorporated them into DNA arrays; (2) prepared antisense constructs and mutants engineered with alterations in C1 unit supply and demand; and (3) have quantified the impacts of these alterations on gene expression (using DNA arrays), and on metabolic fluxes (by combining isotope labeling, MS, NMR and computer modeling). Metabolic flux analysis and modeling in tobacco engineered for GlyBet synthesis by expressing choline oxidizing enzymes in either the chloroplast or cytosol, has shown that the choline biosynthesis network is rigid, and tends to resist large changes in C1 demand. A major constraint on engineering enhanced flux to GlyBet in tobacco is a low capacity of choline transport across the chloroplast envelope. Maize and sorghum mutants defective in GlyBet synthesis show greatly reduced flux of C1 units into choline in comparison to GlyBet-accumulating wildtypes, but this is not associated with altered expression of any of the C1 genes. Control of C1 flux to choline in tobacco, maize and sorghum appears to reside primarily at the level of N-methylation of phosphoethanolamine. A candidate signal for the control of this flux is the pool size of phosphocholine which down-regulates and feedback inhibits phosphoethanolamine N-methyltransferase. Methionine S-methyltransferase (MMT) catalyzes the synthesis of S-methylmethionine (SMM) from methionine (Met) and S-adenosylmethionine (AdoMet). SMM can be

  5. Elucidating central metabolic redox obstacles hindering ethanol production in Clostridium thermocellum.

    Science.gov (United States)

    Thompson, R Adam; Layton, Donovan S; Guss, Adam M; Olson, Daniel G; Lynd, Lee R; Trinh, Cong T

    2015-11-01

    Clostridium thermocellum is an anaerobic, Gram-positive, thermophilic bacterium that has generated great interest due to its ability to ferment lignocellulosic biomass to ethanol. However, ethanol production is low due to the complex and poorly understood branched metabolism of C. thermocellum, and in some cases overflow metabolism as well. In this work, we developed a predictive stoichiometric metabolic model for C. thermocellum which incorporates the current state of understanding, with particular attention to cofactor specificity in the atypical glycolytic enzymes and the complex energy, redox, and fermentative pathways with the goal of aiding metabolic engineering efforts. We validated the model's capability to encompass experimentally observed phenotypes for the parent strain and derived mutants designed for significant perturbation of redox and energy pathways. Metabolic flux distributions revealed significant alterations in key metabolic branch points (e.g., phosphoenol pyruvate, pyruvate, acetyl-CoA, and cofactor nodes) in engineered strains for channeling electron and carbon fluxes for enhanced ethanol synthesis, with the best performing strain doubling ethanol yield and titer compared to the parent strain. In silico predictions of a redox-imbalanced genotype incapable of growth were confirmed in vivo, and a mutant strain was used as a platform to probe redox bottlenecks in the central metabolism that hinder efficient ethanol production. The results highlight the robustness of the redox metabolism of C. thermocellum and the necessity of streamlined electron flux from reduced ferredoxin to NAD(P)H for high ethanol production. The model was further used to design a metabolic engineering strategy to phenotypically constrain C. thermocellum to achieve high ethanol yields while requiring minimal genetic manipulations. The model can be applied to design C. thermocellum as a platform microbe for consolidated bioprocessing to produce ethanol and other reduced

  6. Quantitative Multilevel Analysis of Central Metabolism in Developing Oilseeds of Oilseed Rape during in Vitro Culture.

    Science.gov (United States)

    Schwender, Jörg; Hebbelmann, Inga; Heinzel, Nicolas; Hildebrandt, Tatjana; Rogers, Alistair; Naik, Dhiraj; Klapperstück, Matthias; Braun, Hans-Peter; Schreiber, Falk; Denolf, Peter; Borisjuk, Ljudmilla; Rolletschek, Hardy

    2015-07-01

    Seeds provide the basis for many food, feed, and fuel products. Continued increases in seed yield, composition, and quality require an improved understanding of how the developing seed converts carbon and nitrogen supplies into storage. Current knowledge of this process is often based on the premise that transcriptional regulation directly translates via enzyme concentration into flux. In an attempt to highlight metabolic control, we explore genotypic differences in carbon partitioning for in vitro cultured developing embryos of oilseed rape (Brassica napus). We determined biomass composition as well as 79 net fluxes, the levels of 77 metabolites, and 26 enzyme activities with specific focus on central metabolism in nine selected germplasm accessions. Overall, we observed a tradeoff between the biomass component fractions of lipid and starch. With increasing lipid content over the spectrum of genotypes, plastidic fatty acid synthesis and glycolytic flux increased concomitantly, while glycolytic intermediates decreased. The lipid/starch tradeoff was not reflected at the proteome level, pointing to the significance of (posttranslational) metabolic control. Enzyme activity/flux and metabolite/flux correlations suggest that plastidic pyruvate kinase exerts flux control and that the lipid/starch tradeoff is most likely mediated by allosteric feedback regulation of phosphofructokinase and ADP-glucose pyrophosphorylase. Quantitative data were also used to calculate in vivo mass action ratios, reaction equilibria, and metabolite turnover times. Compounds like cyclic 3',5'-AMP and sucrose-6-phosphate were identified to potentially be involved in so far unknown mechanisms of metabolic control. This study provides a rich source of quantitative data for those studying central metabolism. PMID:25944824

  7. Quantitative Multilevel Analysis of Central Metabolism in Developing Oilseeds of Oilseed Rape During In Vitro Culture

    Energy Technology Data Exchange (ETDEWEB)

    Schwender, Jorg [Brookhaven National Lab. (BNL), Upton, NY (United States); Hebbelmann, Inga [Brookhaven National Lab. (BNL), Upton, NY (United States); Heinzel, Nicholas [Leibniz Inst. of Plant Genetics and Crop Plant Research, Gatersleben (Germany); Hildebrandt, Tatjana [Univ. of Hannover (Germany); Rogers, Alistair [Brookhaven National Lab. (BNL), Upton, NY (United States); Naik, Dhiraj [Brookhaven National Lab. (BNL), Upton, NY (United States); Indian Inst. of Advanced Research Koba, Gujarat (India); Klapperstuck, Matthias [Monash Univ., Melbourne, VIC (Australia); Braun, Hans -Peter [Univ. of Hannover (Germany); Schreiber, Falk [Monash Univ., Melbourne, VIC (Australia); Univ. Halle-Wittenberg, Melbourne (Australia); Denolf, Peter [Bayer CropScience (Belgium); Borisjuk, Ljudmilla [Leibniz Inst. of Plant Genetics and Crop Plant Research, Gatersleben (Germany); Rolletschek, Hardy [Leibniz Inst. of Plant Genetics and Crop Plant Research, Gatersleben (Germany)

    2015-07-01

    Seeds provide the basis for many food, feed, and fuel products. Continued increases in seed yield, composition, and quality require an improved understanding of how the developing seed converts carbon and nitrogen supplies into storage. Current knowledge of this process is often based on the premise that transcriptional regulation directly translates via enzyme concentration into flux. In an attempt to highlight metabolic control, we explore genotypic differences in carbon partitioning for in vitro cultured developing embryos of oilseed rape (Brassica napus). We determined biomass composition as well as 79 net fluxes, the levels of 77 metabolites, and 26 enzyme activities with specific focus on central metabolism in nine selected germplasm accessions. We observed a tradeoff between the biomass component fractions of lipid and starch. With increasing lipid content over the spectrum of genotypes, plastidic fatty acid synthesis and glycolytic flux increased concomitantly, while glycolytic intermediates decreased. The lipid/starch tradeoff was not reflected at the proteome level, pointing to the significance of (posttranslational) metabolic control. Enzyme activity/flux and metabolite/flux correlations suggest that plastidic pyruvate kinase exerts flux control and that the lipid/starch tradeoff is most likely mediated by allosteric feedback regulation of phosphofructokinase and ADP-glucose pyrophosphorylase. Also, quantitative data were used to calculate in vivo mass action ratios, reaction equilibria, and metabolite turnover times. Compounds like cyclic 3',5'-AMP and sucrose-6-phosphate were identified to potentially be involved in so far unknown mechanisms of metabolic control. This study provides a rich source of quantitative data for those studying central metabolism..

  8. Transcript abundance on its own cannot be used to infer fluxes in central metabolism

    OpenAIRE

    Jörg eSchwender; Christina eKönig; Matthias eKlapperstück; Nicolas eHeinzel; Eberhard eMunz; Inga eHebbelmann; Jordan O. Hay; Peter eDenolf; Stefanie De Bodt; Henning eRedestig; Evelyne eCaestecker; Peter M. Jakob; Ljudmilla eBorisjuk; Hardy eRolletschek

    2014-01-01

    An attempt has been made to define the extent to which metabolic flux in central plant metabolism is reflected by changes in the transcriptome and metabolome, based on an analysis of in vitro cultured immature embryos of two oilseed rape (Brassica napus) accessions which contrast for seed lipid accumulation. Metabolic flux analysis was used to constrain a flux balance metabolic model which included 671 biochemical and transport reactions within the central metabolism. This highly confident fl...

  9. Transcript abundance on its own cannot be used to infer fluxes in central metabolism

    OpenAIRE

    Schwender, Jörg; König, Christina; Klapperstück, Matthias; Heinzel, Nicolas; Munz, Eberhard; Hebbelmann, Inga; Jordan O. Hay; Denolf, Peter; De Bodt, Stefanie; Redestig, Henning; Caestecker, Evelyne; Peter M. Jakob; Borisjuk, Ljudmilla; Rolletschek, Hardy

    2014-01-01

    An attempt has been made to define the extent to which metabolic flux in central plant metabolism is reflected by changes in the transcriptome and metabolome, based on an analysis of in vitro cultured immature embryos of two oilseed rape (Brassica napus) accessions which contrast for seed lipid accumulation. Metabolic flux analysis (MFA) was used to constrain a flux balance metabolic model which included 671 biochemical and transport reactions within the central metabolism. This highly confid...

  10. Molecular Basis of Microbial One-Carbon Metabolism

    Energy Technology Data Exchange (ETDEWEB)

    None

    2002-07-12

    The Gordon Research Conference (GRC) on Molecular Basis of Microbial One-Carbon Metabolism was held at Connecticut College, New London, Connecticut. Emphasis was placed on current unpublished research and discussion of the future target areas in this field.

  11. An Integrative Approach to Energy, Carbon, and Redox Metabolism in the Cyanobacterium Synechocystis sp. PCC 6803. Special Report

    Energy Technology Data Exchange (ETDEWEB)

    Overbeek, R.

    2003-06-30

    The main objectives for the first year were to produce a detailed metabolic reconstruction of synechocystis sp. PCC 6803 especially in interrelated areas of photosynthesis, respiration, and central carbon metabolism to support a more complete understanding and modeling of this organism. Additionally, Integrated Genomics, Inc., provided detailed bioinformatic analysis of selected functional systems related to carbon and energy generation and utilization, and of the corresponding pathways, functional roles and individual genes to support wet lab experiments by collaborators.

  12. Central metabolic pathways of Aureobasidium pullulans CGMCC1234 for pullulan production.

    Science.gov (United States)

    Sheng, Long; Liu, Chang; Tong, Qunyi; Ma, Meihu

    2015-12-10

    With the purpose of understanding the metabolic network of Aureobasidium pullulans, the central metabolic pathways were confirmed by the activities of the key enzymes involved in different pathways. The effect of different iodoacetic acid concentrations on pullulan fermentation was also investigated in this paper. The activities of phosphofructokinases and glucose-6-phosphate dehydrogenase existed in A. pullulans CGMCC1234, whereas 2-keto-3-deoxy-6-phosphogluconate aldolase activity was not detected. We proposed that the central metabolic pathways of A. pullulans CGMCC1234 included EMP and PPP, but no ED. Pullulan production declined fast as the iodoacetic acid increased, while cell growth offered upgrade firstly than descending latter tendency. Compared to the control group, the ratio of ATP/ADP of 0.60 mM iodoacetic acid group was lower at different stages of pullulan fermentation. The findings revealed that low concentration of iodoacetic acid might impel carbon flux flow toward the PPP, but reduce the flux of the EMP. PMID:26428132

  13. Carbon isotopic fractionation in heterotrophic microbial metabolism

    Science.gov (United States)

    Blair, N.; Leu, A.; Munoz, E.; Olsen, J.; Kwong, E.; Des Marais, D.

    1985-01-01

    Differences in the natural-abundance carbon stable isotopic compositions between products from aerobic cultures of Escherichia coli K-12 were measured. Respired CO2 was 3.4 percent depleted in C-13 relative to the glucose used as the carbon source, whereas the acetate was 12.3 percent enriched in C-13. The acetate C-13 enrichment was solely in the carboxyl group. Even though the total cellular carbon was only 0.6 percent depleted in C-13, intracellular components exhibited a significant isotopic heterogeneity. The protein and lipid fractions were -1.1 and -2.7 percent, respectively. Aspartic and glutamic acids were -1.6 and +2.7 percent, respectively, yet citrate was isotopically identical to the glucose. Probable sites of carbon isotopic fractionation include the enzyme, phosphotransacetylase, and the Krebs cycle.

  14. Neural-metabolic coupling in the central visual pathway.

    Science.gov (United States)

    Freeman, Ralph D; Li, Baowang

    2016-10-01

    Studies are described which are intended to improve our understanding of the primary measurements made in non-invasive neural imaging. The blood oxygenation level-dependent signal used in functional magnetic resonance imaging (fMRI) reflects changes in deoxygenated haemoglobin. Tissue oxygen concentration, along with blood flow, changes during neural activation. Therefore, measurements of tissue oxygen together with the use of a neural sensor can provide direct estimates of neural-metabolic interactions. We have used this relationship in a series of studies in which a neural microelectrode is combined with an oxygen micro-sensor to make simultaneous co-localized measurements in the central visual pathway. Oxygen responses are typically biphasic with small initial dips followed by large secondary peaks during neural activation. By the use of established visual response characteristics, we have determined that the oxygen initial dip provides a better estimate of local neural function than the positive peak. This contrasts sharply with fMRI for which the initial dip is unreliable. To extend these studies, we have examined the relationship between the primary metabolic agents, glucose and lactate, and associated neural activity. For this work, we also use a Doppler technique to measure cerebral blood flow (CBF) together with neural activity. Results show consistent synchronously timed changes such that increases in neural activity are accompanied by decreases in glucose and simultaneous increases in lactate. Measurements of CBF show clear delays with respect to neural response. This is consistent with a slight delay in blood flow with respect to oxygen delivery during neural activation.This article is part of the themed issue 'Interpreting BOLD: a dialogue between cognitive and cellular neuroscience'. PMID:27574310

  15. Biochemical Hypermedia: Glucose as a Central Molecule in Metabolism

    Directory of Open Access Journals (Sweden)

    J.K. Sugai

    2008-05-01

    Full Text Available The technologies of information, together with education resources, have been pointed out as a solution to the improvement of teaching approach, but they still claim for programs to fulfill the demands of didactic materials. So, a biochemical software was developed aiming to contribute for the better understanding of the glycolysis. It was prepared with the help of concept maps, ISIS Draw, ADOBE Photoshop and FLASH MX Program. The introduction screen shows a teacher in a theater presenting glucose as a central molecule in the metabolism of animals, plants and many microorganisms. She invites for a better knowledge of glucose through a view of its discovery and its metabolism. A step by step animation process shows the interaction of glucose in aerobic conditions with the enzymes of the glycolytic pathways and its products. An explanation text of each enzyme catalytic process is provided by links. A static pathway is always available through a link. The fates of pyruvate yielding lactic acid and ethanol under anaerobic conditions are shown as well. The overall reactions of gluconeogenesis and the functional significance of this pathway are presented. The experimental treatment involved the presentation of this hypermedia for Nutrition undergraduate students (UFSC as a tool for better comprehension of the theme. The students revealed that it was extremely effective in promoting the understanding of the enzymatic mechanisms involved in glycolysis. This suggests that there is a significant added value in employing the software as an instructional effort to enhance student’s abilities to understand biochemical pathways.

  16. Molecular Basis of Microbial One-Carbon Metabolism 2008 Gordon Research Conference (July 20-25, 2008)

    Energy Technology Data Exchange (ETDEWEB)

    Stephen W. Ragsdale

    2009-08-12

    One-carbon (C-1) compounds play a central role in microbial metabolism. C-1 compounds include methane, carbon monoxide, CO2, and methanol as well as coenzyme-bound one-carbon compounds (methyl-B12, CH3-H4folate, etc). Such compounds are of broad global importance because several C-1 compounds (e.g., CH4) are important energy sources, some (e.g., CO2 and CH4) are potent greenhouse gases, and others (e.g., CH2Cl2) are xenobiotics. They are central in pathways of energy metabolism and carbon fixation by microbes and many are of industrial interest. Research on the pathways of one-carbon metabolism has added greatly to our understanding of evolution, structural biology, enzyme mechanisms, gene regulation, ecology, and applied biology. The 2008 meeting will include recent important findings in the following areas: (a) genomics, metagenomics, and proteomic studies that have expanded our understanding of autotrophy and C-1 metabolism and the evolution of these pathways; (b) redox regulation of carbon cycles and the interrelationship between the carbon cycle and other biogeochemical cycles (sulfur, nitrogen, oxygen); (c) novel pathways for carbon assimilation; (d) biotechnology related to C-1 metabolism; (e) novel enzyme mechanisms including channeling of C-1 intermediates during metabolism; and (f) the relationship between metal homeostasis and the global carbon cycle. The conference has a diverse and gender-balanced slate of speakers and session leaders. The wide variety of disciplines brought to the study of C-1 metabolism make the field an excellent one in which to train young researchers.

  17. Preferential use of central metabolism in vivo reveals a nutritional basis for polymicrobial infection.

    Directory of Open Access Journals (Sweden)

    Christopher J Alteri

    2015-01-01

    Full Text Available The human genitourinary tract is a common anatomical niche for polymicrobial infection and a leading site for the development of bacteremia and sepsis. Most uncomplicated, community-acquired urinary tract infections (UTI are caused by Escherichia coli, while another bacterium, Proteus mirabilis, is more often associated with complicated UTI. Here, we report that uropathogenic E. coli and P. mirabilis have divergent requirements for specific central pathways in vivo despite colonizing and occupying the same host environment. Using mutants of specific central metabolism enzymes, we determined glycolysis mutants lacking pgi, tpiA, pfkA, or pykA all have fitness defects in vivo for P. mirabilis but do not affect colonization of E. coli during UTI. Similarly, the oxidative pentose phosphate pathway is required only for P. mirabilis in vivo. In contrast, gluconeogenesis is required only for E. coli fitness in vivo. The remarkable difference in central pathway utilization between E. coli and P. mirabilis during experimental UTI was also observed for TCA cycle mutants in sdhB, fumC, and frdA. The distinct in vivo requirements between these pathogens suggest E. coli and P. mirabilis are not direct competitors within host urinary tract nutritional niche. In support of this, we found that co-infection with E. coli and P. mirabilis wild-type strains enhanced bacterial colonization and persistence of both pathogens during UTI. Our results reveal that complementary utilization of central carbon metabolism facilitates polymicrobial disease and suggests microbial activity in vivo alters the host urinary tract nutritional niche.

  18. Computer Modeling of Carbon Metabolism Enables Biofuel Engineering (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2011-09-01

    In an effort to reduce the cost of biofuels, the National Renewable Energy Laboratory (NREL) has merged biochemistry with modern computing and mathematics. The result is a model of carbon metabolism that will help researchers understand and engineer the process of photosynthesis for optimal biofuel production.

  19. Carbon conversion and metabolic rate in two marine sponges

    NARCIS (Netherlands)

    Koopmans, M.; Van Rijswijk, P.; Martens, D.; Egorova-Zachernyuk, T.A.; Middelburg, J.J.; Wijffels, R.H.

    2011-01-01

    The carbon metabolism of two marine sponges, Haliclona oculata and Dysidea avara, has been studied using a 13C isotope pulse-chase approach. The sponges were fed 13C-labeled diatoms (Skeletonema costatum) for 8 h and they took up between 75 and 85%. At different times, sponges were sampled for total

  20. Carbonate platform growth and demise offshore Central Vietnam

    DEFF Research Database (Denmark)

    Fyhn, Michael B.W.; Boldreel, Lars Ole; Nielsen, Lars H.;

    2013-01-01

    Miocene carbonate platforms cover a large part of the Central Vietnamese South China Sea margin. Early carbonate deposition took place on two regional platforms separated by a narrow depression developed along the trace of the East Vietnam Boundary Fault Zone. West of the East Vietnam Boundary...... nutrient input derived from the uplifted mainland, possibly enhanced by deteriorated climatic conditions and rapid sea-level fluctuations promoting platform drowning....

  1. Floodplain Organic Carbon Storage in the Central Yukon River Basin

    Science.gov (United States)

    Lininger, K.; Wohl, E.

    2014-12-01

    Floodplain storage of organic carbon is an important aspect of the global carbon cycle that is not well understood or quantified. Although it is understood that rivers transport organic carbon to the ocean, little is known about the quantity of stored carbon in boreal floodplains and the influence of fluvial processes on this storage. We present results on total organic carbon (TOC) content within the floodplains of two rivers, the Dall River and Preacher Creek, in the central Yukon River Basin in the Yukon Flats National Wildlife Refuge of Alaska. The results indicate that organic carbon storage is influenced by fluvial disturbance and grain size. The Dall River, which contains a large amount of floodplain carbon, is meandering and incised, with well-developed floodplain soils, a greater percentage of relatively old floodplain surfaces and a slower floodplain turnover time, and finer grain sizes. Preacher Creek stores less TOC, transports coarser grain sizes, and has higher rates of avulsion and floodplain turnover time. Within the floodplain of a particular river, large spatial heterogeneity in TOC content also exists as a function of depositional environment and age and vegetation community of the site. In addition, saturated regions of the floodplains, such as abandoned channels and oxbow lakes, contain more TOC compared to drier floodplain environments. Frozen alluvial soils likely contain carbon that could be released into the environment with melting permafrost, and thus quantifying the organic carbon content in the active layer of floodplain soils could provide insight into the characteristics of the permafrost beneath. The hydrology in these regions is changing due to permafrost melt, and floodplain areas usually saturated could be dried out, causing breakdown and outgassing of carbon stored in previously saturated soils. Ongoing work will result in a first-order estimate of active-layer floodplain carbon storage for the central Yukon River Basin.

  2. Flux analysis of central metabolic pathways in the Fe(III)-reducing organism Geobacter metallireducens via 13C isotopiclabeling

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Yinjie J.; Chakraborty, Romy; Martin, Hector Garcia; Chu,Jeannie; Hazen, Terry C.; Keasling, Jay D.

    2007-08-13

    We analyzed the carbon fluxes in the central metabolism ofGeobacter metallireducens strain GS-15 using 13C isotopomer modeling.Acetate labeled in the 1st or 2nd position was the sole carbon source,and Fe-NTA was the sole terminal electron acceptor. The measured labeledacetate uptake rate was 21 mmol/gdw/h in the exponential growth phase.The resulting isotope labeling pattern of amino acids allowed an accuratedetermination of the in vivo global metabolic reaction rates (fluxes)through the central metabolic pathways using a computational isotopomermodel. The model indicated that over 90 percent of the acetate wascompletely oxidized to CO2 via a complete tricarboxylic acid (TCA) cyclewhile reducing iron. Pyruvate carboxylase and phosphoenolpyruvatecarboxykinase were present under these conditions, but enzymes in theglyoxylate shunt and malic enzyme were absent. Gluconeogenesis and thepentose phosphate pathway were mainly employed for biosynthesis andaccounted for less than 3 percent of total carbon consumption. The modelalso indicated surprisingly high reversibility in the reaction betweenoxoglutarate and succinate. This step operates close to the thermodynamicequilibrium possibly because succinate is synthesized via a transferasereaction, and its product, acetyl-CoA, inhibits the conversion ofoxoglutarate to succinate. These findings enable a better understandingof the relationship between genome annotation and extant metabolicpathways in G. metallireducens.

  3. Transcript abundance on its own cannot be used to infer fluxes in central metabolism

    Directory of Open Access Journals (Sweden)

    Jörg eSchwender

    2014-11-01

    Full Text Available An attempt has been made to define the extent to which metabolic flux in central plant metabolism is reflected by changes in the transcriptome and metabolome, based on an analysis of in vitro cultured immature embryos of two oilseed rape (Brassica napus accessions which contrast for seed lipid accumulation. Metabolic flux analysis was used to constrain a flux balance metabolic model which included 671 biochemical and transport reactions within the central metabolism. This highly confident flux information was eventually used for comparative analysis of flux versus transcript (metabolite. Metabolite profiling succeeded in identifying 79 intermediates within the central metabolism, some of which differed quantitatively between the two accessions and displayed a significant shift corresponding to flux. An RNA-Seq based transcriptome analysis revealed a large number of genes which were differentially transcribed in the two accessions, including some enzymes/proteins active in major metabolic pathways. With a few exceptions, differential activity in the major pathways (glycolysis, TCA cycle, amino acid and fatty acid synthesis was not reflected in contrasting abundances of the relevant transcripts. The conclusion was that transcript abundance on its own cannot be used to infer metabolic activity/fluxes in central plant metabolism. This limitation needs to be borne in mind in evaluating transcriptome data and designing metabolic engineering experiments.

  4. Carbon conversion and metabolic rate in two marine sponges.

    Science.gov (United States)

    Koopmans, M; van Rijswijk, P; Martens, D; Egorova-Zachernyuk, T A; Middelburg, J J; Wijffels, R H

    2011-01-01

    The carbon metabolism of two marine sponges, Haliclona oculata and Dysidea avara, has been studied using a (13)C isotope pulse-chase approach. The sponges were fed (13)C-labeled diatoms (Skeletonema costatum) for 8 h and they took up between 75 and 85%. At different times, sponges were sampled for total (13)C enrichment, and fatty acid (FA) composition and (13)C enrichment. Algal biomarkers present in the sponges were highly labeled after feeding but their labeling levels decreased until none was left 10 days after enrichment. The sponge-specific FAs incorporated (13)C label already during the first day and the amount of (13)C label inside these FAs kept increasing until 3 weeks after labeling. The algal-derived carbon captured by the sponges during the 8-h feeding period was thus partly respired and partly metabolized during the weeks following. Apparently, sponges are able to capture enough food during short periods to sustain longer-term metabolism. The change of carbon metabolic rate of fatty acid synthesis due to mechanical damage of sponge tissue was studied by feeding sponges with (13)C isotope-labeled diatom (Pheaodactylum tricornutum) either after or before damaging and tracing back the (13)C content in the damaged and healthy tissue. The filtration and respiration in both sponges responded quickly to damage. The rate of respiration in H. oculata reduced immediately after damage, but returned to its initial level after 6 h. The (13)C data revealed that H. oculata has a higher metabolic rate in the tips where growth occurs compared to the rest of the tissue and that the metabolic rate is increased after damage of the tissue. For D. avara, no differences were found between damaged and non-damaged tissue. However, the filtration rate decreased directly after damage. PMID:24489407

  5. Carbon metabolism of the cryptoendolithic microbiota from the Antarctic desert

    Science.gov (United States)

    Vestal, J. R.; Friedmann, E. I. (Principal Investigator)

    1988-01-01

    The carbon metabolism of the cryptoendolithic microbiota of sandstones from the Ross Desert of Antarctica was studied in situ and in vitro. Organic and inorganic carbon compounds were metabolized by the microbiota, with bicarbonate incorporation into community lipids occurring primarily in the light. Light intensity affected the photometabolism of carbon with a photosynthesis-intensity response optimum at about 200 to 300 micromoles of photons per m2 per s. Photosynthesis was also affected by temperature, with a minimum activity at -5 degrees C, an optimum activity at 15 degrees C, and complete inhibition at 35 degrees C, indicating that the cryptoendolithic community was psychrophilic. The primary source of CO2 for photosynthesis in situ was the atmosphere. CO2 may also be photometabolized by using the carbon produced from respiration within the endolithic community. Photosynthesis occurred maximally when the microbiota was wet with liquid water and to a lesser extent in a humid atmosphere. This simple microbial community, therefore, exists under extremes of water, light, and temperature stress which affect and control its metabolism.

  6. Mitochondrial dysfunction remodels one-carbon metabolism in human cells

    Science.gov (United States)

    Bao, Xiaoyan Robert; Ong, Shao-En; Goldberger, Olga; Peng, Jun; Sharma, Rohit; Thompson, Dawn A; Vafai, Scott B; Cox, Andrew G; Marutani, Eizo; Ichinose, Fumito; Goessling, Wolfram; Regev, Aviv; Carr, Steven A; Clish, Clary B; Mootha, Vamsi K

    2016-01-01

    Mitochondrial dysfunction is associated with a spectrum of human disorders, ranging from rare, inborn errors of metabolism to common, age-associated diseases such as neurodegeneration. How these lesions give rise to diverse pathology is not well understood, partly because their proximal consequences have not been well-studied in mammalian cells. Here we provide two lines of evidence that mitochondrial respiratory chain dysfunction leads to alterations in one-carbon metabolism pathways. First, using hypothesis-generating metabolic, proteomic, and transcriptional profiling, followed by confirmatory experiments, we report that mitochondrial DNA depletion leads to an ATF4-mediated increase in serine biosynthesis and transsulfuration. Second, we show that lesioning the respiratory chain impairs mitochondrial production of formate from serine, and that in some cells, respiratory chain inhibition leads to growth defects upon serine withdrawal that are rescuable with purine or formate supplementation. Our work underscores the connection between the respiratory chain and one-carbon metabolism with implications for understanding mitochondrial pathogenesis. DOI: http://dx.doi.org/10.7554/eLife.10575.001 PMID:27307216

  7. Quantifying the metabolic contribution to δ13C of shell carbonate of Arctica islandica: an experimental calibration

    Science.gov (United States)

    Beirne, E. C.; Wanamaker, A. D.

    2010-12-01

    The stable isotopic composition of dissolved inorganic carbon of seawater (δ13CDIC) can provide a powerful means to investigate atmospheric and oceanic carbon dynamics. Records of past δ13CDIC values of seawater, especially from the extratropical oceans, are needed to better understand how recent climate change and anthropogenic activity (namely fossil fuel emissions) have impacted the global carbon cycle. However, long-term reconstructions of marine δ13CDIC are limited (both spatially and temporally) by a lack of suitable proxy archives, which have undergone a rigorous calibration process. Marine mollusks represent a potential δ13CDIC archive given that the primary source of carbon to their shell material is ambient dissolved inorganic carbon. However, interpretation of this archive is confounded by the additional contribution of respired (or metabolic) carbon to the carbon isotope ratio of shell material (δ13Cshell). Although theoretical models predict that less than 10% of δ13Cshell of marine mollusks is attributable to metabolic carbon, several studies have reported significantly larger contributions of respired carbon (CM) to shell material depending upon the species in question, and in some cases, ontogenetic age. Therefore, species-specific calibrations must be conducted to establish metabolic contribution to δ13Cshell at different stages of ontogeny. The central objective of this study was to quantify the metabolic contribution to the shell carbonate of Arctica islandica L., juveniles and adults, to determine the viability of this species as a paleo-δ13CDIC archive. Results will be presented from an 8-month experimental calibration between δ13CDIC and δ13Cshell of the species Arctica islandica. Adults (25 to 55 years old) and juveniles (1mm/month) allowed for the measurement of three distinct growth periods in order to capture seasonal variability in metabolic carbon incorporation. δ13CDIC was measured every two weeks during the course of the

  8. Thyroid Hormone Receptor beta Mediates Acute Illness-Induced Alterations in Central Thyroid Hormone Metabolism

    NARCIS (Netherlands)

    A. Boelen; J. Kwakkel; O. Chassande; E. Fliers

    2009-01-01

    Acute illness in mice profoundly affects thyroid hormone metabolism in the hypothalamus and pituitary gland. It remains unknown whether the thyroid hormone receptor (TR)-beta is involved in these changes. In the present study, we investigated central thyroid hormone metabolism during lipopolysacchar

  9. Comprehensive evaluation of one-carbon metabolism pathway gene variants and renal cell cancer risk.

    Directory of Open Access Journals (Sweden)

    Todd M Gibson

    Full Text Available INTRODUCTION: Folate and one-carbon metabolism are linked to cancer risk through their integral role in DNA synthesis and methylation. Variation in one-carbon metabolism genes, particularly MTHFR, has been associated with risk of a number of cancers in epidemiologic studies, but little is known regarding renal cancer. METHODS: Tag single nucleotide polymorphisms (SNPs selected to produce high genomic coverage of 13 gene regions of one-carbon metabolism (ALDH1L1, BHMT, CBS, FOLR1, MTHFR, MTR, MTRR, SHMT1, SLC19A1, TYMS and the closely associated glutathione synthesis pathway (CTH, GGH, GSS were genotyped for 777 renal cell carcinoma (RCC cases and 1,035 controls in the Central and Eastern European Renal Cancer case-control study. Associations of individual SNPs (n = 163 with RCC risk were calculated using unconditional logistic regression adjusted for age, sex and study center. Minimum p-value permutation (Min-P tests were used to identify gene regions associated with risk, and haplotypes were evaluated within these genes. RESULTS: The strongest associations with RCC risk were observed for SLC19A1 (P(min-P = 0.03 and MTHFR (P(min-P = 0.13. A haplotype consisting of four SNPs in SLC19A1 (rs12483553, rs2838950, rs2838951, and rs17004785 was associated with a 37% increased risk (p = 0.02, and exploratory stratified analysis suggested the association was only significant among those in the lowest tertile of vegetable intake. CONCLUSIONS: To our knowledge, this is the first study to comprehensively examine variation in one-carbon metabolism genes in relation to RCC risk. We identified a novel association with SLC19A1, which is important for transport of folate into cells. Replication in other populations is required to confirm these findings.

  10. Central Obesity and Metabolic Risk Factors in Middle-aged Chinese

    Institute of Scientific and Technical Information of China (English)

    YIN Xue Yao; ZHENG Fen Ping; ZHOU Jia Qiang; DU Ying; PAN Qian Qian; ZHANG Sai Fei; YU Dan; LI Hong

    2014-01-01

    Objective Central obesity is considered to be a central component of metabolic syndrome. Waist circumference (WC) has been widely used as a simple indicator of central obesity. This study is aimed to evaluate the sensitivity of WC cut-off values for predicting metabolic risk factors in middle-aged Chinese. Methods The study involved 923 subjects aged 40-65 years. The metabolic risk factors were defined according to the Chinese Joint Committee for Developing Chinese Guidelines on Prevention and Treatment of Dyslipidemia in Adults. WC cut-off 85-90 cm and≥90 cm were used as cut-off values of central pre-obesity and central obesity in males, respectively, while WC 80-85 cm and≥85 cm were used as cut-off values of central pre-obesity and central obesity in females. Results First, WC values corresponding to body mass index (BMI) 24 kg/m2 and visceral fat area (VFA) 80 cm2 were 88.55 cm and 88.51 cm in males, and 81.46 cm and 82.51 cm in females respectively. Second, receiver operating characteristic curves showed that the optimal WC cut-off of value was 88.75 cm in males, higher than that in females (81.75 cm). Third, the subjects with higher WC values were more likely to have accumulating metabolic risk factors. The prevalence of metabolic risk factors increased linearly and significantly in relation to WC levels. Conclusion WC cut-off values of central pre-/central obesity are optimal to predict multiple metabolic risk factors.

  11. Transcriptional regulation of central amino acid metabolism in Lactococcus lactis

    NARCIS (Netherlands)

    Larsen, Rasmus

    2005-01-01

    This thesis describes the functional characterisation of the transcriptional regulators GlnR, ArgR and AhrC of Lactococcus lactis, which are responsible for the control of genes involved in the metabolism of the amino acids glutamine, glutamate and arginine. A chromosomal glnR deletion mutant was ma

  12. Fatty Acids in Energy Metabolism of the Central Nervous System

    Directory of Open Access Journals (Sweden)

    Alexander Panov

    2014-01-01

    Full Text Available In this review, we analyze the current hypotheses regarding energy metabolism in the neurons and astroglia. Recently, it was shown that up to 20% of the total brain’s energy is provided by mitochondrial oxidation of fatty acids. However, the existing hypotheses consider glucose, or its derivative lactate, as the only main energy substrate for the brain. Astroglia metabolically supports the neurons by providing lactate as a substrate for neuronal mitochondria. In addition, a significant amount of neuromediators, glutamate and GABA, is transported into neurons and also serves as substrates for mitochondria. Thus, neuronal mitochondria may simultaneously oxidize several substrates. Astrocytes have to replenish the pool of neuromediators by synthesis de novo, which requires large amounts of energy. In this review, we made an attempt to reconcile β-oxidation of fatty acids by astrocytic mitochondria with the existing hypothesis on regulation of aerobic glycolysis. We suggest that, under condition of neuronal excitation, both metabolic pathways may exist simultaneously. We provide experimental evidence that isolated neuronal mitochondria may oxidize palmitoyl carnitine in the presence of other mitochondrial substrates. We also suggest that variations in the brain mitochondrial metabolic phenotype may be associated with different mtDNA haplogroups.

  13. Invariability of Central Metabolic Flux Distribution in Shewanella oneidensis MR-1 Under Environmental or Genetic Perturbations

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Yinjie; Martin, Hector Garcia; Deutschbauer, Adam; Feng, Xueyang; Huang, Rick; Llora, Xavier; Arkin, Adam; Keasling, Jay D.

    2009-04-21

    An environmentally important bacterium with versatile respiration, Shewanella oneidensis MR-1, displayed significantly different growth rates under three culture conditions: minimal medium (doubling time {approx} 3 hrs), salt stressed minimal medium (doubling time {approx} 6 hrs), and minimal medium with amino acid supplementation (doubling time {approx}1.5 hrs). {sup 13}C-based metabolic flux analysis indicated that fluxes of central metabolic reactions remained relatively constant under the three growth conditions, which is in stark contrast to the reported significant changes in the transcript and metabolite profiles under various growth conditions. Furthermore, ten transposon mutants of S. oneidensis MR-1 were randomly chosen from a transposon library and their flux distributions through central metabolic pathways were revealed to be identical, even though such mutational processes altered the secondary metabolism, for example, glycine and C1 (5,10-Me-THF) metabolism.

  14. An integrative approach to energy, carbon, and redox metabolism in the cyanobacterium Synechocystis sp. PCC 6803

    Energy Technology Data Exchange (ETDEWEB)

    Overbeek, Ross; Fonstein, Veronika; Osterman, Andrei; Gerdes, Svetlana; Vassieva, Olga; Zagnitko, Olga; Rodionov, Dmitry

    2005-02-15

    covering energy, carbon, and redox metabolism in the Synechocystis sp. PCC 6803 and other cyanobacteria has been performed (Specific Aim 4). The main objectives for this year (adjusted to reflect a new, public domain, setting of the Project research team) were: Aim 1. To develop, test, and deploy a new open source system, the SEED, for integrating community-based annotation, and comparative analysis of all publicly available microbial genomes. Develop a comprehensive genomic database by integrating within SEED all publicly available complete and nearly complete genome sequences with special emphasis on genomes of cyanobacteria, phototrophic eukaryotes, and anoxygenic phototrophic bacteria--invaluable for comparative genomic studies of energy and carbon metabolism in Synechocystis sp. PCC 6803. Aim 2. To develop the SEED's biological content in the form of a collection of encoded Subsystems largely covering the conserved cellular machinery in prokaryotes (and central metabolic machinery in eukaryotes). Aim 3. To develop, utilizing core SEED technology, the CyanoSEED--a specialized WEB portal for community-based annotation, and comparative analysis of all publicly available cyanobacterial genomes. Encode the set of additional subsystems representing key metabolic transformations in cyanobacteria and other photoautotrophs. We envisioned this resource as complementary to other public access databases for comparative genomic analysis currently available to the cyanobacterial research community. Aim 4. Perform in-depth analysis of several subsystems covering energy, carbon, and redox metabolism in the Synechocystis sp. PCC 6803 and all other cyanobacteria with available genome sequences. Reveal inconsistencies and gaps in the current knowledge of these subsystems. Use functional and genome context analysis tools in CyanoSEED to predict, whenever possible, candidate genes for inferred functional roles. To disseminate freely these conjectures and predictions by publishing

  15. Correlations between carbon metabolism and virulence in bacteria.

    Science.gov (United States)

    Poncet, Sandrine; Milohanic, Eliane; Mazé, Alain; Nait Abdallah, Jamila; Aké, Francine; Larribe, Mireille; Deghmane, Ala-Eddine; Taha, Muhamed-Kheir; Dozot, Marie; De Bolle, Xavier; Letesson, Jean Jacques; Deutscher, Josef

    2009-01-01

    Bacteria have developed several mechanisms which allow the preferred utilization of the most efficiently metabolizable carbohydrates when these organisms are exposed to a mixture of carbon sources. Interestingly, the same or similar mechanisms are used by some pathogens to control various steps of their infection process. The efficient metabolism of a carbon source might serve as signal for proper fitness. Alternatively, the presence of a specific carbon source might indicate to bacterial cells that they thrive in infection-related organs, tissues or cells and that specific virulence genes should be turned on or switched off. Frequently, virulence gene regulators are affected by changes in carbon source availability. For example, expression of the gene encoding the Streptococcus pyogenes virulence regulator Mga is controlled by the classical carbon catabolite repression (CCR) mechanism operative in Firmicutes. The activity of PrfA, the major virulence regulator in Listeria monocytogenes, seems to be controlled by the phosphorylation state of phosphotransferase system(PTS) components. In Vibrio cholerae synthesis of HapR, which regulates the expression of genes required for motility, is controlled via the Crp/cAMP CCR mechanism, whereas synthesis of Salmonella enterica HilE, which represses genes in a pathogenicity island, is regulated by the carbohydrate-responsive, PTS-controlled Mlc.

  16. PKM2, a Central Point of Regulation in Cancer Metabolism

    Directory of Open Access Journals (Sweden)

    Nicholas Wong

    2013-01-01

    Full Text Available Aerobic glycolysis is the dominant metabolic pathway utilized by cancer cells, owing to its ability to divert glucose metabolites from ATP production towards the synthesis of cellular building blocks (nucleotides, amino acids, and lipids to meet the demands of proliferation. The M2 isoform of pyruvate kinase (PKM2 catalyzes the final and also a rate-limiting reaction in the glycolytic pathway. In the PK family, PKM2 is subjected to a complex regulation by both oncogenes and tumour suppressors, which allows for a fine-tone regulation of PKM2 activity. The less active form of PKM2 drives glucose through the route of aerobic glycolysis, while active PKM2 directs glucose towards oxidative metabolism. Additionally, PKM2 possesses protein tyrosine kinase activity and plays a role in modulating gene expression and thereby contributing to tumorigenesis. We will discuss our current understanding of PKM2's regulation and its many contributions to tumorigenesis.

  17. Carbon and energy metabolism of atp mutants of Escherichia coli

    DEFF Research Database (Denmark)

    Jensen, Peter Ruhdal; Michelsen, Ole

    1992-01-01

    The membrane-bound H+-ATPase plays a key role in free-energy transduction of biological systems. We report how the carbon and energy metabolism of Escherichia coli changes in response to deletion of the atp operon that encodes this enzyme. Compared with the isogenic wild-type strain, the growth...... of reducing equivalents. We interpret these data as indicating that E. coli makes use of its ability to respire even if it cannot directly couple this ability to ATP synthesis; by respiring away excess reducing equivalents E. coli enhances substrate level ATP synthesis....

  18. Framing REDD+ in India: Carbonizing and centralizing Indian forest governance?

    International Nuclear Information System (INIS)

    Highlights: • We analyze whether India's REDD+ strategy induces carbonization and centralization. • REDD+ in India is framed as an opportunity for synergistic, decentralized governance. • Yet national safeguards are not as strong as asserted. • Controversial issues have so far been side-lined in India's REDD+ strategy. • Without investments, synergistic and decentralized REDD+ governance remains unlikely. - Abstract: This article analyzes the interaction of newly articulated climate governance goals with long-standing forest policies and practices in India. We focus on India's REDD+ (reducing emissions from deforestation and forest degradation and related forest activities) strategy, with a particular focus on the Green India Mission (GIM). The GIM calls for a doubling of the area for afforestation and reforestation in India in the next decade as a dominant climate mitigation strategy. We analyze how the GIM policy document frames carbon versus non-carbon benefits to be derived from forest-related activities; and how the GIM envisages division of authority (between national, regional and local levels) in its implementation. We are interested in assessing (a) whether the GIM promotes a “carbonization” of Indian forest governance, i.e. an increased focus on forest carbon at the expense of other ecosystem services; and (b) whether it promotes an increased centralization of forest governance in India through retaining or transferring authority and control over forest resources to national and state-level authorities, at the expense of local communities. We argue that the GIM frames the climate-forest interaction as an opportunity to synergistically enhance both carbon and non-carbon benefits to be derived from forests; while simultaneously promoting further decentralization of Indian forest governance. However, based on past experiences and developments to date, we conclude that without significant investments in community-based carbon and biodiversity

  19. Export and Metabolism of Carbon in Urban Watersheds: Climate Implications

    Science.gov (United States)

    Smith, R. M.; Kaushal, S.

    2014-12-01

    Rivers export and transform globally-significant quantities of carbon from watersheds to coastal ecosystems. Urbanization and climate change influence these fluxes by altering the hydrologic regime, water temperature, and anthropogenic sources of organic matter. Here, we quantify export and metabolism of carbon in highly urbanized, coastal watersheds, and evaluate the importance of physical drivers linked to climate and land use. Using a combination of discrete-samples, continuous water quality sensors, lab experiments, and modeling, we quantified rates of DOC, DIC, and CO2 export as well as changes in DOC quality and in-stream metabolism in four highly developed watersheds of the Chesapeake Bay over three years. Annual DOC and DIC exports from the four watersheds varied from 9 to 23 and 19 to 59 Kg ha-1yr-1 respectively. The range of daily CO2 concentrations was 0.01 to 2.6mg L-1, equivalent to between 0.37 and 53% of daily DOC export across all streams and dates. All sites were net-heterotrophic for the majority of the year (NEP0) during spring and early summer. There was a significant (Purban watersheds can export significant amounts of DOC, DIC, and CO2 to coastal zones. The influence of urbanization on coastal water quality and greenhouse gases may be exacerbated by climate change as temperatures and storm frequency continue to rise.

  20. One carbon metabolism in SAR11 pelagic marine bacteria.

    Directory of Open Access Journals (Sweden)

    Jing Sun

    Full Text Available The SAR11 Alphaproteobacteria are the most abundant heterotrophs in the oceans and are believed to play a major role in mineralizing marine dissolved organic carbon. Their genomes are among the smallest known for free-living heterotrophic cells, raising questions about how they successfully utilize complex organic matter with a limited metabolic repertoire. Here we show that conserved genes in SAR11 subgroup Ia (Candidatus Pelagibacter ubique genomes encode pathways for the oxidation of a variety of one-carbon compounds and methyl functional groups from methylated compounds. These pathways were predicted to produce energy by tetrahydrofolate (THF-mediated oxidation, but not to support the net assimilation of biomass from C1 compounds. Measurements of cellular ATP content and the oxidation of (14C-labeled compounds to (14CO(2 indicated that methanol, formaldehyde, methylamine, and methyl groups from glycine betaine (GBT, trimethylamine (TMA, trimethylamine N-oxide (TMAO, and dimethylsulfoniopropionate (DMSP were oxidized by axenic cultures of the SAR11 strain Ca. P. ubique HTCC1062. Analyses of metagenomic data showed that genes for C1 metabolism occur at a high frequency in natural SAR11 populations. In short term incubations, natural communities of Sargasso Sea microbial plankton expressed a potential for the oxidation of (14C-labeled formate, formaldehyde, methanol and TMAO that was similar to cultured SAR11 cells and, like cultured SAR11 cells, incorporated a much larger percentage of pyruvate and glucose (27-35% than of C1 compounds (2-6% into biomass. Collectively, these genomic, cellular and environmental data show a surprising capacity for demethylation and C1 oxidation in SAR11 cultures and in natural microbial communities dominated by SAR11, and support the conclusion that C1 oxidation might be a significant conduit by which dissolved organic carbon is recycled to CO(2 in the upper ocean.

  1. One-carbon metabolism in acetogenic and sulfate-reducing bacteria

    OpenAIRE

    Visser, M.

    2015-01-01

    ABSTRACT One-carbon metabolism in acetogenic and sulfate-reducing bacteria Life on earth is sustained by the constant cycling of six essential elements: oxygen, hydrogen, nitrogen, sulfur, phosphorous, and carbon. The continuous cycling of these elements is due to geo-chemical processes and the combined metabolism of all life on earth. Microorganisms like bacteria and archaea play a major role in this. This is also true for the carbon cycle. In this cycle carbon dioxide and methane are two im...

  2. Central Pathways Integrating Metabolism and Reproduction in Teleosts

    Directory of Open Access Journals (Sweden)

    Md eShahjahan

    2014-03-01

    Full Text Available Energy balance plays an important role in the control of reproduction. However, the cellular and molecular mechanisms connecting the two systems are not well understood especially in teleosts. The hypothalamus plays a crucial role in the regulation of both energy balance and reproduction, and contains a number of neuropeptides, including gonadotropin-releasing hormone (GnRH, orexin, neuropeptide-Y (NPY, ghrelin, pituitary adenylate cyclase-activating polypeptide (PACAP, α-melanocyte stimulating hormone (α-MSH, melanin-concentrating hormone (MCH, cholecystokinin (CCK, 26RFa, nesfatin, kisspeptin, and gonadotropin-inhibitory hormone (GnIH. These neuropeptides are involved in the control of energy balance and reproduction either directly or indirectly. On the other hand, synthesis and release of these hypothalamic neuropeptides are regulated by metabolic signals from the gut and the adipose tissue. Furthermore, neurons producing these neuropeptides interact with each other, providing neuronal basis of the link between energy balance and reproduction. This review summarizes the advances made in our understanding of the physiological roles of the hypothalamic neuropeptides in energy balance and reproduction in teleosts, and discusses how they interact with GnRH, kisspeptin, and pituitary gonadotropins to control reproduction in teleosts.

  3. Staphylococcus aureus redirects central metabolism to increase iron availability.

    Directory of Open Access Journals (Sweden)

    David B Friedman

    2006-08-01

    Full Text Available Staphylococcus aureus pathogenesis is significantly influenced by the iron status of the host. However, the regulatory impact of host iron sources on S. aureus gene expression remains unknown. In this study, we combine multivariable difference gel electrophoresis and mass spectrometry with multivariate statistical analyses to systematically cluster cellular protein response across distinct iron-exposure conditions. Quadruplicate samples were simultaneously analyzed for alterations in protein abundance and/or post-translational modification state in response to environmental (iron chelation, hemin treatment or genetic (Deltafur alterations in bacterial iron exposure. We identified 120 proteins representing several coordinated biochemical pathways that are affected by changes in iron-exposure status. Highlighted in these experiments is the identification of the heme-regulated transport system (HrtAB, a novel transport system which plays a critical role in staphylococcal heme metabolism. Further, we show that regulated overproduction of acidic end-products brought on by iron starvation decreases local pH resulting in the release of iron from the host iron-sequestering protein transferrin. These findings reveal novel strategies used by S. aureus to acquire scarce nutrients in the hostile host environment and begin to define the iron and heme-dependent regulons of S. aureus.

  4. One-Carbon Metabolism in Prostate Cancer: The Role of Androgen Signaling

    Science.gov (United States)

    Corbin, Joshua M.; Ruiz-Echevarría, Maria J.

    2016-01-01

    Cancer cell metabolism differs significantly from the metabolism of non-transformed cells. This altered metabolic reprogramming mediates changes in the uptake and use of nutrients that permit high rates of proliferation, growth, and survival. The androgen receptor (AR) plays an essential role in the establishment and progression of prostate cancer (PCa), and in the metabolic adaptation that takes place during this progression. In its role as a transcription factor, the AR directly affects the expression of several effectors and regulators of essential catabolic and biosynthetic pathways. Indirectly, as a modulator of the one-carbon metabolism, the AR can affect epigenetic processes, DNA metabolism, and redox balance, all of which are important factors in tumorigenesis. In this review, we focus on the role of AR-signaling on one-carbon metabolism in tumorigenesis. Clinical implications of one-carbon metabolism and AR-targeted therapies for PCa are discussed in this context. PMID:27472325

  5. [Biogeneous carbon fluxes in the boreal forests of Central Siberia].

    Science.gov (United States)

    Vedrova, É F

    2011-01-01

    The assessments of the carbon pool and rate of plant biomass production, phytodetritus destruction, new formations of humic matters, and removal of water-soluble decomposition products for the forest ecosystems of the forest tundra and the northern and southern parts of the Central Siberian taiga were given. The rates of the main processes (organic-matter production and degradation) were demonstrated to be balanced in the ecosystems of the forest tundra. The larch forests of the northern taiga serve as a stock for a C atmosphere, which are equivalent to 32-34% of net primary production (NPP). The secondary birch growth where the understory needle-leaved trees have been formed and the primary old-growth fir forests are characterized by the balance of the main carbon fluxes in the southern taiga. The birch forests where the understory trees are just being formed and the fir forests at the age of 50-90 years serve as a stock for an average of 26% of carbon extracted as dioxide to make NPP. PMID:21442909

  6. Nitrogen, carbon, and sulfur metabolism in natural Thioploca samples

    DEFF Research Database (Denmark)

    Otte, S.; Kuenen, JG; Nielsen, LP;

    1999-01-01

    Filamentous sulfur bacteria of the genus Thioploca occur as dense mats on the continental shelf off the coast of Chile and Peru. Since little is known about their nitrogen, sulfur, and carbon metabolism, this study was undertaken to investigate their (eco)physiology. Thioploca is able to store...... internally high concentrations of sulfur globules and nitrate. It has been previously hypothesized that these large vacuolated bacteria can oxidize sulfide by reducing their internally stored nitrate. We examined this nitrate reduction by incubation experiments of washed Thioploca sheaths,vith trichomes in......) mg of protein(-1). The ammonium and sulfate production rates were not influenced by the addition of sulfide, suggesting that sulfide is first oxidized to elemental sulfur, and in a second independent step elemental sulfur is oxidized to sulfate. The average sulfide oxidation rate measured was 5 nmol...

  7. Preschool Weight and Body Mass Index in Relation to Central Obesity and Metabolic Syndrome in Adulthood

    DEFF Research Database (Denmark)

    Graversen, Lise; Sørensen, Thorkild I A; Petersen, Liselotte;

    2014-01-01

    BACKGROUND: If preschool measures of body size routinely collected at preventive health examinations are associated with adult central obesity and metabolic syndrome, a focused use of these data for the identification of high risk children is possible. The aim of this study was to test...... the associations between preschool weight and body mass index (BMI) and adult BMI, central obesity and metabolic alterations. METHODS: The Northern Finland Birth Cohort 1966 (NFBC1966) (N = 4111) is a population-based cohort. Preschool weight (age 5 months and 1 year) and BMI (age 2-5 years) were studied...... of adult obesity of 6.2(95% CI:4.2-9.3), of adult central obesity of 2.4(95% CI:2.0-2.9), and of early onset adult metabolic syndrome of 2.5(95% CI:1.7-3.8). CONCLUSIONS: High preschool BMI is consistently associated with adult obesity, central obesity and early onset metabolic syndrome. Routinely...

  8. Central obesity measurements predict metabolic syndrome in a retrospective cohort study of postmenopausal women

    Directory of Open Access Journals (Sweden)

    Manuel Rosety-Rodríguez

    2013-12-01

    Full Text Available Introduction: The various diagnostic classifications in the literature concur as regards the important role of abdominal obesity in the onset and progression of metabolic syndrome. Accordingly, this study was aimed at clarifying whether central obesity measurements assessed by dual X-ray absorptiometry (DXA may predict metabolic syndrome in Spanish postmenopausal women. Material and methods: This historical cohort study included a total of 1326 postmenopausal women aged > 45 years old who had routinely undergone DXA to measure their bone mineral density between january 2006 and january 2011. The regions of interest (ROI envisaged in our study by using DXA were the lumbar regions L1-L4 and L4-L5. At the same time, they underwent a complete medical examination including personal medical history assessment, biochemical blood analysis, blood pressure measurement and anthropometrical evaluation. Metabolic syndrome was diagnosed attending to the criteria established by National Cholesterol Education Program Adult Treatment Panel III (NECP-ATP-III. Results: During the observation period, 537 women, representing 40.5% of the total studied, met the diagnostic criteria for metabolic syndrome. L1-L4 and L4-L5 abdominal fat mass determinations were associated with the development of metabolic syndrome in all regression models tested, showing an increasing gradient from the lowest to highest quintile. Conclusion: Central adiposity measurements assessed by DXA, especially L1-L4 region of interest, could be considered a powerful predictor of metabolic syndrome in postmenopausal women.

  9. Carbon and oxygen isotope compositions of the carbonate facies in the Vindhyan Supergroup, central India

    Indian Academy of Sciences (India)

    S Banerjee; S K Bhattacharya; S Sarkar

    2006-02-01

    The Vindhyan sedimentary succession in central India spans a wide time bracket from the Paleopro- terozoic to the Neoproterozoic period.Chronostratigraphic significance of stable carbon and oxygen isotope ratios of the carbonate phase in Vindhyan sediments has been discussed in some recent studies.However,the subtle controls of facies variation,depositional setting and post-depositional diagenesis on stable isotope compositions are not yet clearly understood.The Vindhyan Super- group hosts four carbonate units,exhibiting a wide variability in depositional processes and paleogeography.A detailed facies-specific carbon and oxygen isotope study of the carbonate units was undertaken by us to investigate the effect of these processes and to identify the least altered isotope values.It is seen that both carbon and oxygen isotope compositions have been affected by early meteoric water diagenesis.The effect of diagenetic alteration is,however,more pronounced in case of oxygen isotopes than carbon isotopes.Stable isotope compositions remained insensitive to facies only when sediments accumulated in a shallow shelf setting without being exposed.Major alteration of original isotope ratios was observed in case of shallow marine carbonates,which became exposed to meteoric fluids during early diagenetic stage.Duration of exposure possibly determined the magnitude of alteration and shift from the original values.Moreover,dolomitization is found to be accompanied by appreciable alteration of isotope compositions in some of the carbonates.The present study suggests that variations in sediment depositional settings,in particular the possibility of subaerial exposure,need to be considered while extracting chronostratigraphic signi ficance from 13C data.

  10. No Association of SNPs in One-Carbon Metabolism Genes with Prostate Cancer Risk

    OpenAIRE

    Stevens, Victoria L; Rodriguez, Carmen; Sun, Juzhong; Talbot, Jeffrey T.; Michael J Thun; Eugenia E Calle

    2008-01-01

    One-carbon metabolism mediates the inter-conversion of folates for the synthesis of precursors used in DNA synthesis, repair and methylation. Inadequate folate nutrition or compromised metabolism can disrupt these processes and facilitate carcinogenesis. In this study, we investigated associations of 39 candidate SNPs in nine one-carbon metabolism genes with risk of prostate cancer using 1,144 cases and 1,144 controls from the Cancer Prevention Study-II Nutrition Cohort. None of these SNPs we...

  11. Effects of overexpression glucosamine deaminase on glucosamine synthesis and central carbon metabolism in Escherichia coli%过表达氨基葡萄糖脱氨酶对大肠杆菌氨基葡萄糖合成及中心碳代谢的影响

    Institute of Scientific and Technical Information of China (English)

    王珊珊; 高璐; 严明; 许琳

    2013-01-01

    The effects on glucosamine synthesis and central carbon metabolism in E.coli by overexpression glucosamine deaminase were investigated.The results showed that overexpression glucosamine deaminase nagB could improved the content of glucosamine by two times of that of Rosetta,under the conditions of 36 g/L glucose,pH 9.0,after 24 h fermentation.The content of pyruvate was 1.48 times,acetic acid was 1.74 times,citric acid was 2.99 times,α-ketoglutaric acid was 2.73 times of that of Rosetta,respectirely.Lactic acid content of recombinant was 2.53 g/L.Lactic acid content of the original bacteria was not detected.These preliminary findings showed that,overexpression of the glucosamine deaminase promoted the accumulation of glucosamine in E.coli,overexpression of the glucosamine deaminase also made the accumulation of pyruvate,acetic acid and lactic acid.Overexpression of the glucosamine deaminase has great impact on the TCA cycle,high level of the citric acid and α-ketoglutaric acid were detected.%考察过表达氨基葡萄糖脱氨酶对氨基葡萄糖合成及大肠杆菌(Escherichia coli中心碳代谢的影响.实验结果表明:过表达氨基葡萄糖脱氨酶使得在36 g/L葡萄糖,pH为9.0的发酵条件下,发酵24 h后,重组菌发酵液中氨基葡萄糖、丙酮酸和乙酸的量分别是对照菌Rosetta的2.1、1.48和1.74倍;而乳酸的量为2.53 g/L,对照菌Rosetta发酵液中的乳酸含量未检测到,重组菌发酵液中柠檬酸及α-酮戊二酸的含量分别是Rosetta的2.99和2.73倍.

  12. Enhancing Carbon Fixation by Metabolic Engineering: A Model System of Complex Network Modulation

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Gregory Stephanopoulos

    2008-04-10

    In the first two years of this research we focused on the development of a DNA microarray for transcriptional studies in the photosynthetic organism Synechocystis and the elucidation of the metabolic pathway for biopolymer synthesis in this organism. In addition we also advanced the molecular biological tools for metabolic engineering of biopolymer synthesis in Synechocystis and initiated a series of physiological studies for the elucidation of the carbon fixing pathways and basic central carbon metabolism of these organisms. During the last two-year period we focused our attention on the continuation and completion of the last task, namely, the development of tools for basic investigations of the physiology of these cells through, primarily, the determination of their metabolic fluxes. The reason for this decision lies in the importance of fluxes as key indicators of physiology and the high level of information content they carry in terms of identifying rate limiting steps in a metabolic pathway. While flux determination is a well-advanced subject for heterotrophic organisms, for the case of autotrophic bacteria, like Synechocystis, some special challenges had to be overcome. These challenges stem mostly from the fact that if one uses {sup 13}C labeled CO{sub 2} for flux determination, the {sup 13}C label will mark, at steady state, all carbon atoms of all cellular metabolites, thus eliminating the necessary differentiation required for flux determination. This peculiarity of autotrophic organisms makes it imperative to carry out flux determination under transient conditions, something that had not been accomplished before. We are pleased to report that we have solved this problem and we are now able to determine fluxes in photosynthetic organisms from stable isotope labeling experiments followed by measurements of label enrichment in cellular metabolites using Gas Chromatography-Mass Spectrometry. We have conducted extensive simulations to test the method and

  13. Nonstructural leaf carbohydrates dynamics of Pinus edulis during drought-induced tree mortality reveal role for carbon metabolism in mortality mechanism

    Science.gov (United States)

    Adams, Henry D.; Germino, Matthew J.; Breshears, David D.; Barron-Gafford, Greg A.; Guardiola-Claramonte, Maite; Zou, Chris B.; Huxman, Travis E.

    2013-01-01

    * Vegetation change is expected with global climate change, potentially altering ecosystem function and climate feedbacks. However, causes of plant mortality, which are central to vegetation change, are understudied, and physiological mechanisms remain unclear, particularly the roles of carbon metabolism and xylem function.

  14. One carbon metabolism in anaerobic bacteria: Regulation of carbon and electron flow during organic acid production

    Energy Technology Data Exchange (ETDEWEB)

    Zeikus, J.G.; Jain, M.

    1993-12-31

    The project deals with understanding the fundamental biochemical mechanisms that physiologically control and regulate carbon and electron flow in anaerobic chemosynthetic bacteria that couple metabolism of single carbon compounds and hydrogen to the production of organic acids (formic, acetic, butyric, and succinic) or methane. The authors compare the regulation of carbon dioxide and hydrogen metabolism by fermentation, enzyme, and electron carrier analysis using Butyribacterium methylotrophicum, Anaeroblospirillum succiniciproducens, Methanosarcina barkeri, and a newly isolated tri-culture composed of a syntrophic butyrate degrader strain IB, Methanosarcina mazei and Methanobacterium formicicum as model systems. To understand the regulation of hydrogen metabolism during butyrate production or acetate degradation, hydrogenase activity in B. methylotrophicum or M. barkeri is measured in relation to growth substrate and pH; hydrogenase is purified and characterized to investigate number of hydrogenases; their localization and functions; and, their sequences are determined. To understand the mechanism for catabolic CO{sub 2} fixation to succinate the PEP carboxykinase enzyme and gene of A. succiniciproducens are purified and characterized. Genetically engineered strains of Escherichia coli containing the phosphoenolpyruvate (PEP) carboxykinase gene are examined for their ability to produce succinate in high yield. To understand the mechanism of fatty acid degradation by syntrophic acetogens during mixed culture methanogenesis formate and hydrogen production are characterized by radio tracer studies. It is intended that these studies provide strategies to improve anaerobic fermentations used for the production of organic acids or methane and, new basic understanding on catabolic CO{sub 2} fixation mechanisms and on the function of hydrogenase in anaerobic bacteria.

  15. Soil metabolic transformations of carbon-14-myo-inositol, carbon-14-phytic acid and carbon-14-iron(III) phytate

    International Nuclear Information System (INIS)

    Uniformly labelled 14C-phytic acid and 14C-iron(III) phytate were synthesized from uniformly labelled 14C-myo-inositol. The three compounds were incubated in an Andosol sandy loam at 70% field capacity and 36.50C for a 12-day period. Myo-inositol, phytic acid and iron(III) phytate underwent a 61.0, 1.9 and 0% microbial oxidation respectively to CO2 during the incubation period. The rate of fixation of 14C-phytic acid was illustrated by its rapid decline in metabolism in the 12-day period. The metabolism rate of phytic was considerably reduced by the presumed formation of iron(III) and aluminium phytate. The metabolism rate of myo-inositol was reduced nine-fold after an initial rapid metabolism during the first day of incubation. The following mechanisms were observed in the soil metabolism of myo-inositol: (1) soil mineral-inositol carbon adsorption, (2) humic acid-inositol carbon adsorption, (3) the phosphorylation of myo-inositol, and (4) the epimerization of myo-inositol to chiro-inositol. The formation of (1) and (2) was found to be highly dependent upon microbial activity. Interactions (1), (2) and (3)are considered as possible mechanisms for the inhibition of the microbial oxidation of myo-inositol. The inhibition of myo-inositol oxidation via adsorption or phosphorylation is considered to be due to the chemical blockage of the stereo-specific microbial oxidative attack on the axial hydroxyl group. (author)

  16. Central metabolic responses to the overproduction of fatty acids in Escherichia coli based on 13C-metabolic flux analysis.

    Science.gov (United States)

    He, Lian; Xiao, Yi; Gebreselassie, Nikodimos; Zhang, Fuzhong; Antoniewiez, Maciek R; Tang, Yinjie J; Peng, Lifeng

    2014-03-01

    We engineered a fatty acid overproducing Escherichia coli strain through overexpressing tesA (“pull”) and fadR (“push”) and knocking out fadE (“block”). This “pull-push-block” strategy yielded 0.17 g of fatty acids (C12–C18) per gram of glucose (equivalent to 48% of the maximum theoretical yield) in batch cultures during the exponential growth phase under aerobic conditions. Metabolic fluxes were determined for the engineered E. coli and its control strain using tracer ([1,2-13C]glucose) experiments and 13C-metabolic flux analysis. Cofactor (NADPH) and energy (ATP) balances were also investigated for both strains based on estimated fluxes. Compared to the control strain, fatty acid overproduction led to significant metabolic responses in the central metabolism: (1) Acetic acid secretion flux decreased 10-fold; (2) Pentose phosphate pathway and Entner–Doudoroff pathway fluxes increased 1.5- and 2.0-fold, respectively; (3) Biomass synthesis flux was reduced 1.9-fold; (4) Anaplerotic phosphoenolpyruvate carboxylation flux decreased 1.7-fold; (5) Transhydrogenation flux converting NADH to NADPH increased by 1.7-fold. Real-time quantitative RT-PCR analysis revealed the engineered strain increased the transcription levels of pntA (encoding the membrane-bound transhydrogenase) by 2.1-fold and udhA (encoding the soluble transhydrogenase) by 1.4-fold, which is in agreement with the increased transhydrogenation flux. Cofactor and energy balances analyses showed that the fatty acid overproducing E. coli consumed significantly higher cellular maintenance energy than the control strain. We discussed the strategies to future strain development and process improvements for fatty acid production in E. coli.

  17. Carbon dioxide and methane emission dynamics in central London (UK)

    Science.gov (United States)

    Helfter, Carole; Nemitz, Eiko; Barlow, Janet F.; Wood, Curtis R.

    2013-04-01

    London, with a population of 8.2 million, is the largest city in Europe. It is heavily built-up (typically 8% vegetation cover within the central boroughs) and boasts some of the busiest arteries in Europe despite efforts to reduce traffic in the city centre with the introduction of a congestion charging scheme in 2007. We report on two substantial pollution monitoring efforts in the heart of London between October 2006 and present. Fluxes of carbon dioxide (CO2) and water (H2O) were measured continuously by eddy-covariance in central London from October 2006 until May 2008 from a 190 m telecommunication tower (BT tower; 51° 31' 17.4'' N 0° 8' 20.04'' W). The eddy-covariance system consisted of a Gill R3-50 ultrasonic anemometer operated at 20 Hz and a LI-COR 6262 infrared gas analyser. Air was sampled 0.3 m below the sensor head of the ultrasonic anemometer - which was itself mounted on a 3 m mast to the top of a 15 m lattice tower situated on the roof of the tower (instrument head at 190 m above street level) - and pulled down 45 m of 12.7 mm OD Teflon tubing. In addition, meteorological variables (temperature, relative humidity, pressure, precipitation, wind speed and direction) were also measured with a multi-sensor (Weather Transmitter WXT510, Vaisala). Eddy-covariance measurements at the BT tower location were reinstated in July 2011 and include methane (CH4), CO2 and H2O concentrations measured by a Picarro fast methane analyser (G2301-f). CO2 emissions were found to be mainly controlled by fossil fuel combustion (e.g. traffic, commercial and domestic heating). Diurnal averages of CO2 fluxes were found to be highly correlated to traffic. However changes in heating-related natural gas consumption and, to a lesser extent, photosynthetic activity in two large city centre green spaces (Hyde Park and Regent's Park) explained the seasonal variability. Annual estimates of net exchange of CO2 obtained by eddy-covariance agreed well with up-scaled data from the UK

  18. One carbon metabolism in pregnancy: Impact on maternal, fetal and neonatal health.

    Science.gov (United States)

    Kalhan, Satish C

    2016-11-01

    One carbon metabolism or methyl transfer, a crucial component of metabolism in all cells and tissues, supports the critical function of synthesis of purines, thymidylate and methylation via multiple methyl transferases driven by the ubiquitous methyl donor s-adenosylmethionine. Serine is the primary methyl donor to the one carbon pool. Intracellular folates and methionine metabolism are the critical components of one carbon transfer. Methionine metabolism requires vitamin B12, B6 as cofactors and is modulated by endocrine signals and is responsive to nutrient intake. Perturbations in one carbon transfer can have profound effects on cell proliferation, growth and function. Epidemiological studies in humans and experimental model have established a strong relationship between impaired fetal growth and the immediate and long term consequences to the health of the offspring. It is speculated that during development, maternal environmental and nutrient influences by their effects on one carbon transfer can impact the health of the mother, impair growth and reprogram metabolism of the fetus, and cause long term morbidity in the offspring. The potential for such effects is underscored by the unique responses in methionine metabolism in the human mother during pregnancy, the absence of transsulfuration activity in the fetus, ontogeny of methionine metabolism in the placenta and the unique metabolism of serine and glycine in the fetus. Dietary protein restriction in animals and marginal protein intake in humans causes characteristic changes in one carbon metabolism. The impact of perturbations in one carbon metabolism on the health of the mother during pregnancy, on fetal growth and the neonate are discussed and their possible mechanism explored. PMID:27267668

  19. One carbon metabolism in pregnancy: Impact on maternal, fetal and neonatal health.

    Science.gov (United States)

    Kalhan, Satish C

    2016-11-01

    One carbon metabolism or methyl transfer, a crucial component of metabolism in all cells and tissues, supports the critical function of synthesis of purines, thymidylate and methylation via multiple methyl transferases driven by the ubiquitous methyl donor s-adenosylmethionine. Serine is the primary methyl donor to the one carbon pool. Intracellular folates and methionine metabolism are the critical components of one carbon transfer. Methionine metabolism requires vitamin B12, B6 as cofactors and is modulated by endocrine signals and is responsive to nutrient intake. Perturbations in one carbon transfer can have profound effects on cell proliferation, growth and function. Epidemiological studies in humans and experimental model have established a strong relationship between impaired fetal growth and the immediate and long term consequences to the health of the offspring. It is speculated that during development, maternal environmental and nutrient influences by their effects on one carbon transfer can impact the health of the mother, impair growth and reprogram metabolism of the fetus, and cause long term morbidity in the offspring. The potential for such effects is underscored by the unique responses in methionine metabolism in the human mother during pregnancy, the absence of transsulfuration activity in the fetus, ontogeny of methionine metabolism in the placenta and the unique metabolism of serine and glycine in the fetus. Dietary protein restriction in animals and marginal protein intake in humans causes characteristic changes in one carbon metabolism. The impact of perturbations in one carbon metabolism on the health of the mother during pregnancy, on fetal growth and the neonate are discussed and their possible mechanism explored.

  20. GC-MS/MS survey of collision-induced dissociation of tert-butyldimethylsilyl-derivatized amino acids and its application to (13)C-metabolic flux analysis of Escherichia coli central metabolism.

    Science.gov (United States)

    Okahashi, Nobuyuki; Kawana, Shuichi; Iida, Junko; Shimizu, Hiroshi; Matsuda, Fumio

    2016-09-01

    Stable isotope labeling experiments using mass spectrometry have been employed to investigate carbon flow levels (metabolic flux) in mammalian, plant, and microbial cells. To achieve a more precise (13)C-metabolic flux analysis ((13)C-MFA), novel fragmentations of tert-butyldimethylsilyl (TBDMS)-amino acids were investigated by gas chromatography-tandem mass spectrometry (GC-MS/MS). The product ion scan analyses of 15 TBDMS-amino acids revealed 24 novel fragment ions. The amino acid-derived carbons included in the five fragment ions were identified by the analyses of (13)C-labeled authentic standards. The identification of the fragment ion at m/z 170 indicated that the isotopic abundance of S-methyl carbon in methionine could be determined from the cleavage of C5 in the precursor of [M-159](+) (m/z 218). It was also confirmed that the precision of (13)C-MFA in Escherichia coli central carbon metabolism could be improved by introducing (13)C-labeling data derived from novel fragmentations. Graphical Abstract Novel collision-induced dissociation fragmentations of tert-butyldimethylsilyl amino acids were investigated and identified by GC-MS/MS.

  1. Impacts of proline on the central metabolism of an industrial erythromycin-producing strain Saccharopolyspora erythraea via (13)C labeling experiments.

    Science.gov (United States)

    Hong, Ming; Huang, Mingzhi; Chu, Ju; Zhuang, Yingping; Zhang, Siliang

    2016-08-10

    Saccharopolyspora erythraea E3 is an important industrial strain for erythromycin production and knowledge on its metabolism is limited. In the present work, (13)C labeling experiments were conducted to characterize the metabolism of S. erythraea E3. We found that S. erythraea E3 was difficult to grow on minimal medium with glucose as sole carbon source and the addition of proline remarkably improved the cell growth. The activity of EMP pathway was very low and ED pathway was alternatively the main glucose utilization pathway. The addition of proline resulted in remarkable changes in the fluxes of central metabolism. The fluxes in PP pathway, in TCA cycle and in ED pathway were 90% higher, 64% and 31% lower on Glc/Pro than on Glc, respectively. The maintenance energy on Glc/Pro was 58.4% lower than that on Glc. The energy charge was lower on Glc than on Glc/Pro, indicating that the cells on Glc suffered from energy burden. This study elucidates the impacts of proline on the central metabolism of S. erythraea and deepens the understanding of its metabolism.

  2. Studies on carbon metabolism in wild type and mutants of Aspergillus nidulans

    NARCIS (Netherlands)

    Uitzetter, J.H.A.A.

    1982-01-01

    This thesis deals with carbon metabolism in the lower eukaryote Aspergillus nidulans. This fungus is an attractive organism as a model to study genetics in relation to metabolism in lower eukaryotes.In chapter I the present state of affairs in this field is summarized for A. nidulans and some of the

  3. Targeting one carbon metabolism with an antimetabolite disrupts pyrimidine homeostasis and induces nucleotide overflow

    OpenAIRE

    Ser, Zheng; GAO, XIA; Johnson, Christelle; Mehrmohamadi, Mahya; Liu, Xiaojing; Li, SiQi; Locasale, Jason W.

    2016-01-01

    Anti-metabolite agents that affect nucleotide metabolism are frontline chemotherapy agents in several cancers and often successfully target one carbon metabolism. However, the precise mechanisms and resulting determinants of their therapeutic value are unknown. We show that 5-fluorouracil (5-FU), a commonly used anti-metabolite therapeutic with varying efficacy, induces specific alterations to nucleotide metabolism by disrupting pyrimidine homeostasis. An integrative metabolomics analysis of ...

  4. Role of phosphate in the central metabolism of two lactic acid bacteria-a comparative systems biology approach

    NARCIS (Netherlands)

    Levering, J.; Musters, M.W.J.M.; Bekker, M.; Bellomo, D.; Fiedler, T.; Vos, de W.M.; Hugenholtz, F.; Kreikemeyer, B.; Kummer, U.; Teusink, B.

    2012-01-01

    Lactic acid-producing bacteria survive in distinct environments, but show common metabolic characteristics. Here we studied the dynamic interactions of the central metabolism in Lactococcus lactis, extensively used as a starter culture in the dairy industry, and Streptococcus pyogenes, a human patho

  5. Role of phosphate in the central metabolism of two lactic acid bacteria - a comparative systems biology approach.

    NARCIS (Netherlands)

    J. Levering; M.W. Musters; M. Bekker; D. Bellomo; T. Fiedler; W.M. de Vos; J. Hugenholtz; B. Kreikemeyer; U. Kummer; B. Teusink

    2012-01-01

    Lactic acid-producing bacteria survive in distinct environments, but show common metabolic characteristics. Here we studied the dynamic interactions of the central metabolism in Lactococcus lactis, extensively used as a starter culture in the dairy industry, and Streptococcus pyogenes, a human patho

  6. Central and Metabolic Effects of High Fructose Consumption: Evidence from Animal and Human Studies

    Directory of Open Access Journals (Sweden)

    Alexandra Stoianov

    2014-12-01

    Full Text Available Fructose consumption has increased dramatically in the last 40 years, and its role in the pathogenesis of the metabolic syndrome has been implicated by many studies. It is most often encountered in the diet as sucrose (glucose and fructose or high-fructose corn syrup (55% fructose. At high levels, dietary exposure to fructose triggers a series of metabolic changes originating in the liver, leading to hepatic steatosis, hypertriglyceridemia, insulin resistance, and decreased leptin sensitivity. Fructose has been identified to alter biological pathways in other tissues including the central nervous system (CNS, adipose tissue, and the gastrointestinal system. Unlike glucose, consumption of fructose produces smaller increases in the circulating satiety hormone glucagon-like peptide 1 (GLP-1, and does not attenuate levels of the appetite suppressing hormone ghrelin. In the brain, fructose contributes to increased food consumption by activating appetite and reward pathways, and stimulating hypothalamic AMPK activity, a nutrient-sensitive regulator of food intake. Recent studies investigating the neurophysiological factors linking fructose consumption and weight gain in humans have demonstrated differential activation of brain regions that govern appetite, motivation and reward processing. Compared to fructose, glucose ingestion produces a greater reduction of hypothalamic neuronal activity, and increases functional connectivity between the hypothalamus and other reward regions of the brain, indicating that these two sugars regulate feeding behavior through distinct neural circuits. This review article outlines the current findings in fructose-feeding studies in both human and animal models, and discusses the central effects on the CNS that may lead to increased appetite and food intake. Keywords: Fructose, Metabolic syndrome, Appetite, Central nervous system

  7. Global transcriptomic analysis of Cyanothece 51142 reveals robust diurnal oscillation of central metabolic processes

    Energy Technology Data Exchange (ETDEWEB)

    Stockel, Jana; Welsh, Eric A.; Liberton, Michelle L.; Kunnavakkam, Rangesh V.; Aurora, Rajeev; Pakrasi, Himadri B.

    2008-04-22

    Cyanobacteria are oxygenic photosynthetic organisms, and the only prokaryotes known to have a circadian cycle. Unicellular diazotrophic cyanobacteria such as Cyanothece 51142 can fix atmospheric nitrogen, a process exquisitely sensitive to oxygen. Thus, the intracellular environment of Cyanothece oscillates between aerobic and anaerobic conditions during a day-night cycle. This is accomplished by temporal separation of two processes: photosynthesis during the day, and nitrogen fixation at night. While previous studies have examined periodic changes transcript levels for a limited number of genes in Cyanothece and other unicellular diazotrophic cyanobacteria, a comprehensive study of transcriptional activity in a nitrogen-fixing cyanobacterium is necessary to understand the impact of the temporal separation of photosynthesis and nitrogen fixation on global gene regulation and cellular metabolism. We have examined the expression patterns of nearly 5000 genes in Cyanothece 51142 during two consecutive diurnal periods. We found that ~30% of these genes exhibited robust oscillating expression profiles. Interestingly, this set included genes for almost all central metabolic processes in Cyanothece. A transcriptional network of all genes with significantly oscillating transcript levels revealed that the majority of genes in numerous individual pathways, such as glycolysis, pentose phosphate pathway and glycogen metabolism, were co-regulated and maximally expressed at distinct phases during the diurnal cycle. Our analyses suggest that the demands of nitrogen fixation greatly influence major metabolic activities inside Cyanothece cells and thus drive various cellular activities. These studies provide a comprehensive picture of how a physiologically relevant diurnal light-dark cycle influences the metabolism in a photosynthetic bacterium

  8. Carbon and oxygen isotope geochemistry of Ediacaran outer platform carbonates, Paraguay Belt, central Brazil

    Directory of Open Access Journals (Sweden)

    Claudio Riccomini

    2007-09-01

    Full Text Available After the late Cryogenian glaciation the central region of Brazil was the site of extensive deposition of platformal carbonates of the Araras Group. This group includes a basal cap carbonate sequence succeeded by transgressive, deep platform deposits of bituminous lime mudstone and shale. Facies and stratigraphic data combined with carbon and oxygen isotopic analyses of the most complete section of the transgressive deposits, exposed in the Guia syncline, were used to evaluate the depositional paleoenvironment and to test the correlation of these deposits along the belt and with other units worldwide. The studied succession consists of 150 m thick tabular beds of black to grey lime mudstone and shale with predominantly negative delta13C PDB values around -2.5 to -1‰ . The delta13C PDB profile of Guia syncline shows a clear correlation with the upper portion of Guia Formation in the Cáceres region, about 200 km to the southwest. The delta13C PDB profile of the Araras Group is comparable with delta13C PDB profiles of Ediacaran units of the southern Paraguay Belt, western Canada, and the Congo and Kalahari cratons. Moreover, facies distribution, stratigraphy and the carbon isotopic profile of the Araras Group match the middle Tsumeb Subgroup in Namibia, which reinforces the Ediacaran age assigned to the Araras Group.Após a glaciação do final do Criogeniano, a região central do Brasil foi palco de extensa deposição de carbonatos plataformais do Grupo Araras. Este grupo inclui na sua base uma seqüência de capa carbonática sucedida por depósitos transgressivos de calcilutitos betuminosos e folhelhos de plataforma profunda. Dados de fácies e estratigráficos combinados com análises isotópicas de carbono e oxigênio da seção mais completa desses depósitos transgressivos, expostos no sinclinal da Guia, foram empregados para avaliar o paleambiente deposicional e para testar a correlação desses depósitos ao longo da faixa e tamb

  9. Determining novel functions of Arabidopsis 14-3-3 proteins in central metabolic processes

    Directory of Open Access Journals (Sweden)

    Diaz Celine

    2011-11-01

    Full Text Available Abstract Background 14-3-3 proteins are considered master regulators of many signal transduction cascades in eukaryotes. In plants, 14-3-3 proteins have major roles as regulators of nitrogen and carbon metabolism, conclusions based on the studies of a few specific 14-3-3 targets. Results In this study, extensive novel roles of 14-3-3 proteins in plant metabolism were determined through combining the parallel analyses of metabolites and enzyme activities in 14-3-3 overexpression and knockout plants with studies of protein-protein interactions. Decreases in the levels of sugars and nitrogen-containing-compounds and in the activities of known 14-3-3-interacting-enzymes were observed in 14-3-3 overexpression plants. Plants overexpressing 14-3-3 proteins also contained decreased levels of malate and citrate, which are intermediate compounds of the tricarboxylic acid (TCA cycle. These modifications were related to the reduced activities of isocitrate dehydrogenase and malate dehydrogenase, which are key enzymes of TCA cycle. In addition, we demonstrated that 14-3-3 proteins interacted with one isocitrate dehydrogenase and two malate dehydrogenases. There were also changes in the levels of aromatic compounds and the activities of shikimate dehydrogenase, which participates in the biosynthesis of aromatic compounds. Conclusion Taken together, our findings indicate that 14-3-3 proteins play roles as crucial tuners of multiple primary metabolic processes including TCA cycle and the shikimate pathway.

  10. Conventional tree height-diameter relationships significantly overestimate aboveground carbon stocks in the Central Congo Basin

    NARCIS (Netherlands)

    Kearsley, E.; Haulleville, de T.; Hufkens, K.; Kidimbu, A.; Toirambe, B.; Baert, G.; Huygens, D.; Kebede, Y.; Defourny, P.; Bogaert, J.; Beeckman, H.; Steppe, K.; Boeckx, P.; Verbeeck, H.

    2013-01-01

    Policies to reduce emissions from deforestation and forest degradation largely depend on accurate estimates of tropical forest carbon stocks. Here we present the first field-based carbon stock data for the Central Congo Basin in Yangambi, Democratic Republic of Congo. We find an average aboveground

  11. Seasonal variations in inorganic carbon components in the central and eastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Sarma, V.V.S.S.; DileepKumar, M.; George, M.D.; Rajendran, A.

    and convective mixing. The partial pressure of carbon dioxide (pCO sub(2)) in surface layers was generally in excess over the atmospheriec value, suggesting that the central and eastern Arabian Sea is a perennial source to atmospheric carbon dioxide. The flux...

  12. Spatial variation in the ecological relationships among the components of Beijing's carbon metabolic system.

    Science.gov (United States)

    Xia, Linlin; Fath, Brian D; Scharler, Ursula M; Zhang, Yan

    2016-02-15

    In this paper, we construct a spatially explicit model of carbon metabolism for the flows of carbon among the components of an urban area. We used the model to identify spatial heterogeneity in the ecological relationships within a carbon metabolic network. We combined land-use and cover type maps for Beijing from 1990 to 2010 with empirical coefficients and socioeconomic data to quantify the flows. We used utility analysis to determine the ecological relationships between the components of the system and analyzed their changes during urban development. We used ArcGIS to analyze their spatial variation. We found that the positive utilities in Beijing decreased over time and that negative relationships mostly outweighed positive relationships after 2000. The main ecological relationships were distributed throughout the entire urban area before 2000; subsequently, exploitation, control, and mutualism relationships became concentrated in the southeast, leaving competition relationships to dominate the northwest. Mutualism relationships were most common for natural components, but were not stable because they were easily disturbed by urban expansion. Transportation and industrial land and urban land were the most important contributors to exploitation and control relationships and may be important indicators of spatial adjustment. Increasing competition relationships unbalanced the carbon metabolism, and limitations on the area of land available for development and on the water resources led to increasingly serious competition. The results provide an objective basis for planning adjustments to Beijing's land-use patterns to improve its carbon metabolism and reduce carbon emission.

  13. Integration of Carbon, Nitrogen, and Oxygen Metabolism in Escherichia coli--Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Rabinowitz, Joshua D; Wingreen, Ned s; Rabitz, Herschel A; Xu, Yifan

    2012-10-22

    A key challenge for living systems is balancing utilization of multiple elemental nutrients, such as carbon, nitrogen, and oxygen, whose availability is subject to environmental fluctuations. As growth can be limited by the scarcity of any one nutrient, the rate at which each nutrient is assimilated must be sensitive not only to its own availability, but also to that of other nutrients. Remarkably, across diverse nutrient conditions, E. coli grows nearly optimally, balancing effectively the conversion of carbon into energy versus biomass. To investigate the link between the metabolism of different nutrients, we quantified metabolic responses to nutrient perturbations using LC-MS based metabolomics and built differential equation models that bridge multiple nutrient systems. We discovered that the carbonaceous substrate of nitrogen assimilation, -ketoglutarate, directly inhibits glucose uptake and that the upstream glycolytic metabolite, fructose-1,6-bisphosphate, ultrasensitively regulates anaplerosis to allow rapid adaptation to changing carbon availability. We also showed that NADH controls the metabolic response to changing oxygen levels. Our findings support a general mechanism for nutrient integration: limitation for a nutrient other than carbon leads to build-up of the most closely related product of carbon metabolism, which in turn feedback inhibits further carbon uptake.

  14. Integration of Carbon, Nitrogen, and Oxygen Metabolism in Escherichia coli--Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Rabinowitz, Joshua D; Wingreen, Ned s; Rabitz, Herschel A; Xu, Yifan

    2012-10-22

    A key challenge for living systems is balancing utilization of multiple elemental nutrients, such as carbon, nitrogen, and oxygen, whose availability is subject to environmental fluctuations. As growth can be limited by the scarcity of any one nutrient, the rate at which each nutrient is assimilated must be sensitive not only to its own availability, but also to that of other nutrients. Remarkably, across diverse nutrient conditions, E. coli grows nearly optimally, balancing effectively the conversion of carbon into energy versus biomass. To investigate the link between the metabolism of different nutrients, we quantified metabolic responses to nutrient perturbations using LC-MS based metabolomics and built differential equation models that bridge multiple nutrient systems. We discovered that the carbonaceous substrate of nitrogen assimilation, α-ketoglutarate, directly inhibits glucose uptake and that the upstream glycolytic metabolite, fructose-1,6-bisphosphate, ultrasensitively regulates anaplerosis to allow rapid adaptation to changing carbon availability. We also showed that NADH controls the metabolic response to changing oxygen levels. Our findings support a general mechanism for nutrient integration: limitation for a nutrient other than carbon leads to build-up of the most closely related product of carbon metabolism, which in turn feedback inhibits further carbon uptake.

  15. Evidence for a link between tail biting and central monoamine metabolism in pigs (Sus scrofa domestica).

    Science.gov (United States)

    Valros, Anna; Palander, Pälvi; Heinonen, Mari; Munsterhjelm, Camilla; Brunberg, Emma; Keeling, Linda; Piepponen, Petteri

    2015-05-01

    Tail biting in pigs is a major welfare problem within the swine industry. Even though there is plenty of information on housing and management-related risk factors, the biological bases of this behavioral problem are poorly understood. The aim of this study was to investigate a possible link between tail biting, based on behavioral recordings of pigs during an ongoing outbreak, and certain neurotransmitters in different brain regions of these pigs. We used a total of 33 pigs at a farm with a long-standing problem of tail biting. Three equally big behavioral phenotypic groups, balanced for gender and age were selected, the data thus consisting of 11 trios of pigs. Two of the pigs in each trio originated from the same pen: one tail biter (TB) and one tail biting victim (V). A control (C) pig was selected from a pen without significant tail biting in the same farm room. We found an effect of tail biting behavioral phenotype on the metabolism of serotonin and dopamine, with a tendency for a higher 5-HIAA level in the prefrontal cortex (PFC) of TB compared to the other groups, while V pigs showed changes in both serotonin and dopamine metabolism in the striatum (ST) and limbic cortex (LC). Trp:BCAA and Trp:LNAA correlated positively with serotonin and 5-HIAA in the PFC, but only in TB pigs. Furthermore, in both ST and LC, several of the neurotransmitters and their metabolites correlated positively with the frequency of bites received by the pig. This is the first study indicating a link between brain neurotransmission and tail biting behavior in pigs with TB pigs showing a tendency for increased PFC serotonin metabolism and V pigs showing several changes in central dopamine and serotonin metabolism in their ST and LC, possibly due to the acute stress caused by being bitten. PMID:25728243

  16. Carbon catabolite repression and global control of the carbohydrate metabolism in Lactococcus lactis.

    OpenAIRE

    Luesink, E.J.

    1998-01-01

    In view of the economic importance of fermented dairy products considerable scientific attention has been given to various steps of fermentation processes, including the L-lactate formation of lactic acid bacteria (de Vos, 1996). In particular, the carbohydrate metabolism of L. lactis has been the subject of extensive research and several genes encoding proteins involved in the central carbohydrate metabolism have been described (Llanos et al., 1992; Llanos et al., 1993; Cancilla et al., 1995...

  17. Polymorphisms in 1-Carbon Metabolism, Epigenetics and Folate-Related Pathologies

    OpenAIRE

    Stover, Patrick J.

    2012-01-01

    Folate-mediated 1-carbon metabolism is a network of interconnected metabolic pathways necessary for the synthesis of purine nucleotides, thymidylate and the remethylation of homocysteine to methionine. Disruptions in this pathway influence both DNA synthesis and stability and chromatin methylation, and result from nutritional deficiencies and common gene variants. The mechanisms underlying folate-associated pathologies and developmental anomalies have yet to be established. This review focuse...

  18. Maintenance metabolism and carbon fluxes in Bacillus species

    Directory of Open Access Journals (Sweden)

    Decasper Seraina

    2008-06-01

    Full Text Available Abstract Background Selection of an appropriate host organism is crucial for the economic success of biotechnological processes. A generally important selection criterion is a low maintenance energy metabolism to reduce non-productive consumption of substrate. We here investigated, whether various bacilli that are closely related to Bacillus subtilis are potential riboflavin production hosts with low maintenance metabolism. Results While B. subtilis exhibited indeed the highest maintenance energy coefficient, B. licheniformis and B. amyloliquefaciens exhibited only statistically insignificantly reduced maintenance metabolism. Both B. pumilus and B. subtilis (natto exhibited irregular growth patterns under glucose limitation such that the maintenance metabolism could not be determined. The sole exception with significantly reduced maintenance energy requirements was the B. licheniformis strain T380B. The frequently used spo0A mutation significantly increased the maintenance metabolism of B. subtilis. At the level of 13C-detected intracellular fluxes, all investigated bacilli exhibited a significant flux through the pentose phosphate pathway, a prerequisite for efficient riboflavin production. Different from all other species, B. subtilis featured high respiratory tricarboxylic acid cycle fluxes in batch and chemostat cultures. In particular under glucose-limited conditions, this led to significant excess formation of NADPH of B. subtilis, while anabolic consumption was rather balanced with catabolic NADPH formation in the other bacilli. Conclusion Despite its successful commercial production of riboflavin, B. subtilis does not seem to be the optimal cell factory from a bioenergetic point of view. The best choice of the investigated strains is the sporulation-deficient B. licheniformis T380B strain. Beside a low maintenance energy coefficient, this strain grows robustly under different conditions and exhibits only moderate acetate overflow, hence

  19. Regulation of secondary metabolism by the carbon-nitrogen status in tobacco: nitrate inhibits large sectors of phenylpropanoid metabolism.

    Science.gov (United States)

    Fritz, Christina; Palacios-Rojas, Natalia; Feil, Regina; Stitt, Mark

    2006-05-01

    Interactions between nitrogen and carbon metabolism modulate many aspects of the metabolism, physiology and development of plants. This paper investigates the contribution of nitrate and nitrogen metabolism to the regulation of phenylpropanoid and nicotine synthesis. Wild-type tobacco was grown on 12 or 0.2 mm nitrate and compared with a nitrate reductase-deficient mutant [Nia30(145)] growing on 12 mm nitrate. Nitrate-deficient wild-type plants accumulate high levels of a range of phenylpropanoids including chlorogenic acid, contain high levels of rutin, are highly lignified, but contain less nicotine than nitrogen-replete wild-type tobacco. Nia30(145) resembles nitrate-deficient wild-type plants with respect to the levels of amino acids, but accumulates large amounts of nitrate. The levels of phenylpropanoids, rutin and lignin resemble those in nitrogen-replete wild-type plants, whereas the level of nicotine resembles that in nitrate-deficient wild-type plants. Expression arrays and real time RT-PCR revealed that a set of genes required for phenylpropanoid metabolism including PAL, 4CL and HQT are induced in nitrogen-deficient wild-type plants but not in Nia30(145). It is concluded that nitrogen deficiency leads to a marked shift from the nitrogen-containing alkaloid nicotine to carbon-rich phenylpropanoids. The stimulation of phenylpropanoid metabolism is triggered by changes of nitrate, rather than downstream nitrogen metabolites, and is mediated by induction of a set of enzymes in the early steps of the phenylpropanoid biosynthetic pathway.

  20. Soil microbial community and its interaction with soil carbon and nitrogen dynamics following afforestation in central China.

    Science.gov (United States)

    Deng, Qi; Cheng, Xiaoli; Hui, Dafeng; Zhang, Qian; Li, Ming; Zhang, Quanfa

    2016-01-15

    Afforestation may alter soil microbial community structure and function, and further affect soil carbon (C) and nitrogen (N) dynamics. Here we investigated soil microbial carbon and nitrogen (MBC and MBN) and microbial community [e.g. bacteria (B), fungi (F)] derived from phospholipid fatty acids (PLFAs) analysis in afforested (implementing woodland and shrubland plantations) and adjacent croplands in central China. Relationships of microbial properties with biotic factors [litter, fine root, soil organic carbon (SOC), total nitrogen (TN) and inorganic N], abiotic factors (soil temperature, moisture and pH), and major biological processes [basal microbial respiration, microbial metabolic quotient (qCO2), net N mineralization and nitrification] were developed. Afforested soils had higher mean MBC, MBN and MBN:TN ratios than the croplands due to an increase in litter input, but had lower MBC:SOC ratio resulting from low-quality (higher C:N ratio) litter. Afforested soils also had higher F:B ratio, which was probably attributed to higher C:N ratios in litter and soil, and shifts of soil inorganic N forms, water, pH and disturbance. Alterations in soil microbial biomass and community structure following afforestation were associated with declines in basal microbial respiration, qCO2, net N mineralization and nitrification, which likely maintained higher soil carbon and nitrogen storage and stability.

  1. Central leptin insufficiency syndrome: an interactive etiology for obesity, metabolic and neural diseases and for designing new therapeutic interventions

    OpenAIRE

    Kalra, Satya P.

    2007-01-01

    This review critically reappraises recent scientific evidence concerning central leptin insufficiency versus leptin resistance formulations to explain metabolic and neural disorders resulting from subnormal or defective leptin signaling in various sites in the brain. Research at various fronts to unravel the complexities of the neurobiology of leptin is surveyed to provide a comprehensive account of the neural and metabolic effects of environmentally-imposed fluctuations in leptin availabilit...

  2. Role of Nitrogen and Carbon Transport, Regulation, and Metabolism Genes for Saccharomyces cerevisiae Survival In Vivo†

    OpenAIRE

    Joanne M Kingsbury; Goldstein, Alan L.; McCusker, John H.

    2006-01-01

    Saccharomyces cerevisiae is both an emerging opportunistic pathogen and a close relative of pathogenic Candida species. To better understand the ecology of fungal infection, we investigated the importance of pathways involved in uptake, metabolism, and biosynthesis of nitrogen and carbon compounds for survival of a clinical S. cerevisiae strain in a murine host. Potential nitrogen sources in vivo include ammonium, urea, and amino acids, while potential carbon sources include glucose, lactate,...

  3. Genome-directed analysis of prophage excision, host defence systems, and central fermentative metabolism in Clostridium pasteurianum

    Science.gov (United States)

    Pyne, Michael E.; Liu, Xuejia; Moo-Young, Murray; Chung, Duane A.; Chou, C. Perry

    2016-01-01

    Clostridium pasteurianum is emerging as a prospective host for the production of biofuels and chemicals, and has recently been shown to directly consume electric current. Despite this growing biotechnological appeal, the organism’s genetics and central metabolism remain poorly understood. Here we present a concurrent genome sequence for the C. pasteurianum type strain and provide extensive genomic analysis of the organism’s defence mechanisms and central fermentative metabolism. Next generation genome sequencing produced reads corresponding to spontaneous excision of a novel phage, designated φ6013, which could be induced using mitomycin C and detected using PCR and transmission electron microscopy. Methylome analysis of sequencing reads provided a near-complete glimpse into the organism’s restriction-modification systems. We also unveiled the chief C. pasteurianum Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) locus, which was found to exemplify a Type I-B system. Finally, we show that C. pasteurianum possesses a highly complex fermentative metabolism whereby the metabolic pathways enlisted by the cell is governed by the degree of reductance of the substrate. Four distinct fermentation profiles, ranging from exclusively acidogenic to predominantly alcohologenic, were observed through redox consideration of the substrate. A detailed discussion of the organism’s central metabolism within the context of metabolic engineering is provided. PMID:27641836

  4. Genome-directed analysis of prophage excision, host defence systems, and central fermentative metabolism in Clostridium pasteurianum.

    Science.gov (United States)

    Pyne, Michael E; Liu, Xuejia; Moo-Young, Murray; Chung, Duane A; Chou, C Perry

    2016-01-01

    Clostridium pasteurianum is emerging as a prospective host for the production of biofuels and chemicals, and has recently been shown to directly consume electric current. Despite this growing biotechnological appeal, the organism's genetics and central metabolism remain poorly understood. Here we present a concurrent genome sequence for the C. pasteurianum type strain and provide extensive genomic analysis of the organism's defence mechanisms and central fermentative metabolism. Next generation genome sequencing produced reads corresponding to spontaneous excision of a novel phage, designated φ6013, which could be induced using mitomycin C and detected using PCR and transmission electron microscopy. Methylome analysis of sequencing reads provided a near-complete glimpse into the organism's restriction-modification systems. We also unveiled the chief C. pasteurianum Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) locus, which was found to exemplify a Type I-B system. Finally, we show that C. pasteurianum possesses a highly complex fermentative metabolism whereby the metabolic pathways enlisted by the cell is governed by the degree of reductance of the substrate. Four distinct fermentation profiles, ranging from exclusively acidogenic to predominantly alcohologenic, were observed through redox consideration of the substrate. A detailed discussion of the organism's central metabolism within the context of metabolic engineering is provided. PMID:27641836

  5. Boron nutrition affects the carbon metabolism of silver birch seedlings.

    Science.gov (United States)

    Ruuhola, Teija; Keinänen, Markku; Keski-Saari, Sarita; Lehto, Tarja

    2011-11-01

    Boron (B) is an essential micronutrient whose deficiency is common both in agriculture and in silviculture. Boron deficiency impairs the growth of plants and affects many metabolic processes like carbohydrate metabolism. Boron deficiency and also excess B may decrease the sink demand by decreasing the growth and sugar transport which may lead to the accumulation of carbohydrates and down-regulation of photosynthesis. In this study, we investigated the effects of B nutrition on the soluble and storage carbohydrate concentrations of summer leaves and autumn buds in a deciduous tree species, Betula pendula Roth. In addition, we investigated the changes in the pools of condensed tannins between summer and autumn harvests. One-year-old birch seedlings were fertilized with a complete nutrient solution containing three different levels of B: 0, 30 and 100% of the standard level for complete nutrient solution. Half of the seedlings were harvested after summer period and another half when leaves abscised. The highest B fertilization level (B100) caused an accumulation of starch and a decrease in the concentrations of hexoses (glucose and fructose) in summer leaves, whereas in the B0 seedlings, hexoses (mainly glucose) accumulated and starch decreased. These changes in carbohydrate concentrations might be related to the changes in the sink demand since the autumn growth was the smallest for the B100 seedlings and largest for the B30 seedlings that did not accumulate carbohydrates. The autumn buds of B30 seedlings contained the lowest levels of glucose, glycerol, raffinose and total polyols, which was probably due to the dilution effect of the deposition of other substances like phenols. Condensed tannins accumulated in high amounts in the birch stems during the hardening of seedlings and the largest accumulation was detected in the B30 treatment. Our results suggest that B nutrition of birch seedlings affects the carbohydrate and phenol metabolism and may play an important

  6. Nanostructuring carbon fibre probes for use in central venous catheters.

    Science.gov (United States)

    Li, Meixian; Phair, Jolene; Cardosi, Marco F; Davis, James

    2014-02-17

    A carbon fibre probe is described which utilises the oxidation of an endogenous biomarker to provide diagnostic information on the condition of intravascular access lines. The probe surface was modified through anodic oxidation to provide a high selectivity towards urate which was used as a redox probe through which the pH could be determined. A Nernstian response (-60 mV/pH) was obtained which was free from the interference of other redox species common to biofluids. The electroanalytical performance of the probe has been optimised and the applicability of the approach demonstrated through testing the responses in whole blood.

  7. Carbon and phosphorus regulating bacterial metabolism in oligotrophic boreal lakes

    DEFF Research Database (Denmark)

    Vidal, L. O.; Graneli, W.; Daniel, C. B.;

    2011-01-01

    -P and glucose-C alone or in combination (0.01 and 0.3 mg L(-1), respectively) was added to 1.0 mu m filtered lake water and incubated in darkness at 20 degrees C. Additions of glucose (C) and phosphorus (P) alone did not lead to changes in the rates of bacterial metabolic processes, whereas bacterial...... respiration and bacterial production responded positively to C + P enrichment for most of the lakes sampled. Bacterial growth efficiency showed a wide range (2.5-28.7%) and low mean value (12%). These variations were not correlated with the DOC concentration. Our results show that heterotrophic bacterial...

  8. Biomarkers related to one-carbon metabolism as potential risk factors for distal colorectal adenomas

    NARCIS (Netherlands)

    Vogel, S. de; Schneede, J.; Ueland, P.M.; Vollset, S.E.; Meyer, K.; Fredriksen, A.; Midttun, O.; Bjorge, T.; Kampman, E.; Bretthauer, M.; Hoff, G.

    2011-01-01

    BACKGROUND: Efficient one-carbon metabolism, which requires adequate supply of methyl group donors and B-vitamins, may protect against colorectal carcinogenesis. However, plasma folate and vitamins B2 and B12 have inconsistently been associated with colorectal cancer risk, and there have been no pre

  9. Biomarkers Related to One-Carbon Metabolism as Potential Risk Factors for Distal Colorectal Adenomas

    NARCIS (Netherlands)

    Vogel, de S.; Schneede, J.; Ueland, P.M.; Vollset, S.E.; Meyer, K.; Fredriksen, A.; Midttun, O.; Bjorge, T.; Kampman, E.; Bretthauer, M.; Hoff, G.

    2011-01-01

    Background: Efficient one-carbon metabolism, which requires adequate supply of methyl group donors and B-vitamins, may protect against colorectal carcinogenesis. However, plasma folate and vitamins B2 and B12 have inconsistently been associated with colorectal cancer risk, and there have been no pre

  10. Molecular and Metabolic Mechanisms of Carbon Sequestration in Marine Thrombolites

    Science.gov (United States)

    Mobberley, Jennifer

    2013-01-01

    The overall goal of my dissertation project has been to examine the molecular processes underlying carbon sequestration in lithifying microbial ecosystems, known as thrombolitic mats, and assess their feasibility for use in bioregenerative life support systems. The results of my research and education efforts funded by the Graduate Student Researchers Program can be summarized in four peer-reviewed research publication, one educational publication, two papers in preparation, and six research presentations at local and national science meetings (see below for specific details).

  11. Lack of differential pattern in central adiposity and metabolic syndrome in Barrett's esophagus and gastroesophageal reflux disease.

    LENUS (Irish Health Repository)

    Healy, L A

    2012-02-01

    Obesity is an established risk factor for esophageal adenocarcinoma, although the mechanism is unclear. A pathway from reflux to inflammation through metaplasia is the dominant hypothesis, and an added role relating to visceral adiposity and the metabolic syndrome has been mooted in Barrett\\'s esophagus (BE) patients. Whether BE differs from gastroesophageal reflux disease (GERD) in obesity and metabolic syndrome profiles is unclear, and this was the focus of this study. Patients with proven BE or GERD were randomly selected from the unit data registry and invited to attend for metabolic syndrome screening, anthropometry studies including segmental body composition analysis, and laboratory tests including fasting lipids, insulin, and C-reactive protein. Metabolic syndrome was defined using the National Cholesterol Education Program (NCEP) and the International Diabetes Federation (IDF) criteria. One hundred and eighteen BE patients and 113 age- and sex-matched GERD controls were studied. The incidence of obesity (body mass index >30 kg\\/m(2)) was 36% and 38%, respectively, with the pattern of fat deposition predominantly central and an estimated trunk fat mass of 13 and 14 kg, respectively. Using the NCEP criteria, metabolic syndrome was significantly more common in the BE cohort (30% vs 20%, P < 0.05), but there was no significant difference using IDF criteria (42% vs 37%, P= 0.340). Central obesity and the metabolic syndrome are common in both Barrett\\'s and GERD cohorts, but not significantly different, suggesting that central obesity and the metabolic syndrome does not per se impact on the development of BE in a reflux population. In BE, the importance of obesity and the metabolic syndrome in disease progression merits further study.

  12. Hydrogen isotopic compositions of organic compounds in plants reflect the plant's carbon metabolism

    Science.gov (United States)

    Cormier, M. A.; Kahmen, A.; Werner, R. A.

    2015-12-01

    The main factors controlling δ2H of plant organic compounds are generally assumed to be the plant's source water and the evaporative deuterium enrichment of leaf water. Hydrogen isotope analyses of plant compounds from sediments or tree rings are therefore mainly applied to assess hydrological conditions at different spatial and temporal scales. However, the biochemical hydrogen isotope fractionation occurring during biosynthesis of plant organic compounds (ɛbio) also accounts for a large part of the variability observed in the δ2H values. Nevertheless, only few studies have directly addressed the physiological basis of this variability and even fewer studies have thus explored possible applications of hydrogen isotope variability in plant organic compounds for plant physiological research. Here we show two datasets indicating that the plant's carbon metabolism can have a substantial influence on δ2H values of n-alkanes and cellulose. First, we performed a controlled experiment where we forced plants into heterotrophic and autotrophic C-metabolism by growing them under four different light treatments. Second, we assessed the δ2H values of different parasitic heterotrophic plants and their autotrophic host plants. Our two datasets show a systematic shift in ɛbio of up to 80 ‰ depending on the plant's carbon metabolism (heterotrophic or autotrophic). Differences in n-alkane and cellulose δ2H values in plants with autotrophic vs. heterotrophic metabolisms can be explained by different NADPH pools that are used by the plants to build their compounds either with assimilates that originate directly from photosynthesis or from stored carbohydrates. Our results have significant implications for the calibration and interpretation of geological records. More importantly, as the δ2H values reflect the plant's carbon metabolism involved during the tissue formation, our findings highlight the potential of δ2H values as new tool for studying plant and ecosystem carbon

  13. Samuel Ruben's Contributions to Research on Photosynthesis and Bacterial Metabolism with Radioactive Carbon.

    Science.gov (United States)

    Gest, Howard

    2004-01-01

    The earliest experiments on the pathways of carbon in photosynthetic and heterotrophic metabolism using radioactive carbon, (11)C, as a tracer were performed by Samuel (Sam) Ruben, Martin Kamen, and their colleagues. The short half-life of (11)C (20 min), however, posed severe limitations on identification of metabolic intermediates, and this was a major stimulus to search for a radioactive carbon isotope of longer half-life. (14)C was discovered by Ruben and Kamen in 1940, but circumstances prevented continuation of their research using the long-lived isotope. Because of the untimely accidental death of Ruben in 1943, there are very few published accounts on the life and work of this extraordinary scientist. This paper summarizes highlights of Ruben's outstanding accomplishments. PMID:16328812

  14. Study on the correlation of serum lipid metabolism and central retinal artery hemodynamics with diabetic retinopathy

    Institute of Scientific and Technical Information of China (English)

    Ran-Yang Guo

    2016-01-01

    Objective:To explore the correlation of serum lipid metabolism and central retinal artery (CRA) hemodynamics with diabetic retinopathy (DR).Methods:A total of 120 patients with type 2 diabetes who were admitted in our hospital from May, 2015 to May, 2016 were included in the study and divided into NDR group (non-diabetic retinopathy), NPR group (non-proliferative retinopathy), and PR group (proliferative retinopathy) with 40 cases in each group according to DR clinical staging. Moreover, 50 healthy individuals who came for physical examinations were served as the control group. The full automatic biochemical analyzer was used to detect the levels of TG, TC, LDL-C, and HDL-C. The color Doppler flow imaging (CDFI) was used to detect EDV, PSV, RI, and PI of CRA and OA.Results:The levels of TG, TC, and LDL-C in NDG, NPR, and PR groups were gradually increased with the aggravation of retinopathy, HDL-C was reduced, the comparison among the three groups was statistically significant, and the comparison with the control group was statistically significant. EDV, PSV, and PI of CRA and OA in NDG, NPR, and PR groups were gradually increased with the aggravation of retinopathy, RI was reduced, the comparison among the three groups was statistically significant, and the comparison with the control group was statistically significant. Conclusions: The lipid metabolism disorder can promote the occurrence and development of DR. The change of CRA and OA hemodynamics is an important pathological basis for developing DR. Clinical detection of serum lipid level and monitoring of the changes of fundus artery hemocynamic parameters are of great significance in early detecting DR.

  15. Conventional tree height-diameter relationships significantly overestimate aboveground carbon stocks in the Central Congo Basin

    Science.gov (United States)

    Kearsley, Elizabeth; Hufkens, Koen; Steppe, Kathy; Beeckman, Hans; Boeckx, Pascal; Verbeeck, Hans

    2014-05-01

    Accurate estimates of the amount of carbon stored in tropical forests represent crucial baseline data for recent climate change mitigation policies. Such data are needed to quantify possible emissions due to deforestation and forest degradation, and to evaluate the potential of these forests to act as carbon sinks. Currently, only rough estimates of the carbon stocks for Central African tropical forests are available due to a lack of field data, and little is known about the response of these stocks to climate change. We present the first field-based carbon stock data for the Central Congo Basin in Yangambi, Democratic Republic of Congo. We found an average aboveground carbon stock of 162 ± 20 Mg C ha-1 for intact old-growth forest, which is significantly lower than stocks recorded in the outer regions of the Congo Basin. The best available tree height-diameter relationships derived for Central Africa do not render accurate canopy height estimates for our study area. Aboveground carbon stocks would be overestimated by 24% if these inaccurate relationships were used. The studied forests have a lower stature compared with forests in the outer regions of the basin, which confirms remotely sensed patterns. We identified a significant difference in height-diameter relations across the Congo Basin as a driver for spatial differences in carbon stocks. The study of a more detailed interaction of the environment and the available tree species pool as drivers for differences in carbon storage could have large implications. The effect of the species pool on carbon storage can be large since species differ in their ability to sequester carbon, and the collective functional characteristics of plant communities could be a major driver of carbon accumulation. Numerous species-specific tree height-diameter relations are established for two sites around Kisangani, central Congo Basin, with differing stand height-diameter relationships. The species-specific relations for the two

  16. Carbon Deflagration in Type Ia Supernova: I. Centrally Ignited Models

    CERN Document Server

    Ma, H; Malone, C M; Almgren, A; Bell, J B

    2013-01-01

    A leading model for Type Ia supernovae (SNe Ia) begins with a white dwarf near the Chandrasekhar mass that ignites a degenerate thermonuclear runaway close to its center and explodes. In a series of papers, we shall explore the consequences of ignition at several locations within such dwarfs. Here we assume central ignition, which has been explored before, however, the problem is worth revisiting, if only to validate those previous studies and to further elucidate the relevant physics for future work. A perturbed sphere of hot iron ash with a radius of ~100 km is initialized at the middle of the star. The subsequent explosion is followed in several simulations using a thickened flame model in which the flame speed is either fixed --- within the range expected from turbulent combustion --- or based on the local turbulent intensity. Global results, including the explosion energy and bulk nucleosynthesis (e.g. 56Ni of 0.48--0.56 $\\Msun$) turn out to be insensitive to this speed. In all completed runs, the energy...

  17. Histone Methylation Dynamics and Gene Regulation Occur through the Sensing of One-Carbon Metabolism.

    Science.gov (United States)

    Mentch, Samantha J; Mehrmohamadi, Mahya; Huang, Lei; Liu, Xiaojing; Gupta, Diwakar; Mattocks, Dwight; Gómez Padilla, Paola; Ables, Gene; Bamman, Marcas M; Thalacker-Mercer, Anna E; Nichenametla, Sailendra N; Locasale, Jason W

    2015-11-01

    S-adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH) link one-carbon metabolism to methylation status. However, it is unknown whether regulation of SAM and SAH by nutrient availability can be directly sensed to alter the kinetics of key histone methylation marks. We provide evidence that the status of methionine metabolism is sufficient to determine levels of histone methylation by modulating SAM and SAH. This dynamic interaction led to rapid changes in H3K4me3, altered gene transcription, provided feedback regulation to one-carbon metabolism, and could be fully recovered upon restoration of methionine. Modulation of methionine in diet led to changes in metabolism and histone methylation in the liver. In humans, methionine variability in fasting serum was commensurate with concentrations needed for these dynamics and could be partly explained by diet. Together these findings demonstrate that flux through methionine metabolism and the sensing of methionine availability may allow direct communication to the chromatin state in cells.

  18. Carbon and nitrogen stocks in the soils of Central and Eastern Europe

    NARCIS (Netherlands)

    Batjes, N.H.

    2002-01-01

    Soil organic carbon and total nitrogen stocks are presented for Central and Eastern Europe. The study uses the soil geographic and attribute data held in a 1:2 500 000 scale Soil and Terrain (SOTER) database, covering Belarus, Bulgaria, Czech Republic, Estonia, Hungary, Latvia, Lithuania, Moldova, P

  19. Atmospheric black carbon and warming effects influenced by the source and absorption enhancement in central Europe

    NARCIS (Netherlands)

    Nordmann, S.; Cheng, Y.F.; Carmichael, G.R.; Yu, M.; Denier Van Der Gon, H.A.C.; Zhang, Q.; Saide, P.E.; Pöschl, U.; Su, H.; Birmili, W.; Wiedensohler, A.

    2014-01-01

    Particles containing black carbon (BC), a strong absorbing substance, exert a rather uncertain direct and indirect radiative forcing in the atmosphere. To investigate the mass concentration and absorption properties of BC particles over central Europe, the model WRF-Chem was used at a resolution of

  20. Proteomic Analysis of One-carbon Metabolism-related Marker in Liver of Rat Offspring.

    Science.gov (United States)

    You, Young-Ah; Lee, Ji Hye; Kwon, Eun Jin; Yoo, Jae Young; Kwon, Woo-Sung; Pang, Myung-Geol; Kim, Young Ju

    2015-11-01

    Maternal food intake has a significant effect on the fetal environment, and an inadequate maternal diet may result in intrauterine growth restriction. Intrauterine growth restriction newborn rat pups nursed by normal diet-fed dams exhibited rapid catch-up growth, which plays a critical role in the risk for metabolic and cardiovascular disease in later life. Specifically, one-carbon metabolism in the liver plays a critical role in placental and fetal growth. Impaired functioning of one-carbon metabolism is associated with increased homocysteine levels. In this study, we applied a comprehensive proteomic approach to identify differential expression of proteins related to one-carbon metabolism in the livers of rat offspring as an effect of maternal food restriction during gestation. Data are available via ProteomeXchange with identifier PXD002578. We determined that betaine-homocysteine S-methyltransferase 1, methylenetetrahydrofolate dehydrogenase 1, and ATP synthase subunit beta mitochondrial (ATP5B) expression levels were significantly reduced in the livers of rat offspring exposed to maternal food restriction during gestation compared with in the offspring of rats fed a normal diet (p food restriction during gestation and normal diet during lactation. However, in female offspring only expression levels of methylenetetrahydrofolate dehydrogenase 1 were negatively correlated with homocysteine concentration. This study shows that maternal food restriction during late gestation and normal diet during lactation lead to increased homocysteine concentration through disturbance of one-carbon metabolism in the livers of male offspring. This suggests that male offspring have an increased gender-specific susceptibility to disease in later life through fetal programming.

  1. A metagenomic window into carbon metabolism at 3 km depth in Precambrian continental crust.

    Science.gov (United States)

    Magnabosco, Cara; Ryan, Kathleen; Lau, Maggie C Y; Kuloyo, Olukayode; Sherwood Lollar, Barbara; Kieft, Thomas L; van Heerden, Esta; Onstott, Tullis C

    2016-03-01

    Subsurface microbial communities comprise a significant fraction of the global prokaryotic biomass; however, the carbon metabolisms that support the deep biosphere have been relatively unexplored. In order to determine the predominant carbon metabolisms within a 3-km deep fracture fluid system accessed via the Tau Tona gold mine (Witwatersrand Basin, South Africa), metagenomic and thermodynamic analyses were combined. Within our system of study, the energy-conserving reductive acetyl-CoA (Wood-Ljungdahl) pathway was found to be the most abundant carbon fixation pathway identified in the metagenome. Carbon monoxide dehydrogenase genes that have the potential to participate in (1) both autotrophic and heterotrophic metabolisms through the reversible oxidization of CO and subsequent transfer of electrons for sulfate reduction, (2) direct utilization of H2 and (3) methanogenesis were identified. The most abundant members of the metagenome belonged to Euryarchaeota (22%) and Firmicutes (57%)-by far, the highest relative abundance of Euryarchaeota yet reported from deep fracture fluids in South Africa and one of only five Firmicutes-dominated deep fracture fluids identified in the region. Importantly, by combining the metagenomics data and thermodynamic modeling of this study with previously published isotopic and community composition data from the South African subsurface, we are able to demonstrate that Firmicutes-dominated communities are associated with a particular hydrogeologic environment, specifically the older, more saline and more reducing waters. PMID:26325359

  2. A metagenomic window into carbon metabolism at 3 km depth in Precambrian continental crust.

    Science.gov (United States)

    Magnabosco, Cara; Ryan, Kathleen; Lau, Maggie C Y; Kuloyo, Olukayode; Sherwood Lollar, Barbara; Kieft, Thomas L; van Heerden, Esta; Onstott, Tullis C

    2016-03-01

    Subsurface microbial communities comprise a significant fraction of the global prokaryotic biomass; however, the carbon metabolisms that support the deep biosphere have been relatively unexplored. In order to determine the predominant carbon metabolisms within a 3-km deep fracture fluid system accessed via the Tau Tona gold mine (Witwatersrand Basin, South Africa), metagenomic and thermodynamic analyses were combined. Within our system of study, the energy-conserving reductive acetyl-CoA (Wood-Ljungdahl) pathway was found to be the most abundant carbon fixation pathway identified in the metagenome. Carbon monoxide dehydrogenase genes that have the potential to participate in (1) both autotrophic and heterotrophic metabolisms through the reversible oxidization of CO and subsequent transfer of electrons for sulfate reduction, (2) direct utilization of H2 and (3) methanogenesis were identified. The most abundant members of the metagenome belonged to Euryarchaeota (22%) and Firmicutes (57%)-by far, the highest relative abundance of Euryarchaeota yet reported from deep fracture fluids in South Africa and one of only five Firmicutes-dominated deep fracture fluids identified in the region. Importantly, by combining the metagenomics data and thermodynamic modeling of this study with previously published isotopic and community composition data from the South African subsurface, we are able to demonstrate that Firmicutes-dominated communities are associated with a particular hydrogeologic environment, specifically the older, more saline and more reducing waters.

  3. How does oxygen inhibit central metabolism in the obligate anaerobe Bacteroides thetaiotaomicron.

    Science.gov (United States)

    Pan, N; Imlay, J A

    2001-03-01

    The molecular basis of obligate anaerobiosis is not well established. Bacteroides thetaiotaomicron is an opportunistic pathogen that cannot grow in fully aerobic habitats. Because microbial niches reflect features of energy-producing strategies, we suspected that aeration would interfere with its central metabolism. In anaerobic medium, this bacterium fermented carbohydrates to a mixture of succinate, propionate and acetate. When cultures were exposed to air, the formation of succinate and propionate ceased abruptly. In vitro analysis demonstrated that the fumarase of the succinate-propionate pathway contains an iron-sulphur cluster that is sensitive to superoxide. In vivo, fumarase activity fell to PFOR), the first enzyme in the acetate fermentation branch, to 3% of its anaerobic activity. This cluster-containing enzyme was damaged in vitro by molecular oxygen but not by superoxide. Thus, aerobic growth is precluded by the vulnerability of these iron-sulphur cluster enzymes to oxidation. Importantly, both enzymes were maintained in a stable, inactive form for long periods in aerobic cells; they were then rapidly repaired when the bacterium was returned to anaerobic medium. This result explains how this pathogen can easily recover from occasional exposure to oxygen. PMID:11260473

  4. Cerebral blood flow, oxidative metabolism and cerebrovascular carbon dioxide reactivity in patients with acute bacterial meningitis

    DEFF Research Database (Denmark)

    Møller, Kirsten; Strauss, Gitte Irene; Thomsen, Gerda;

    2002-01-01

    BACKGROUND: The optimal arterial carbon dioxide tension (P(a)CO(2)) in patients with acute bacterial meningitis (ABM) is unknown and controversial. The objective of this study was to measure global cerebral blood flow (CBF), cerebrovascular CO(2) reactivity (CO(2)R), and cerebral metabolic rates...... to baseline ventilation, whereas CMR(glu) increased. CONCLUSION: In patients with acute bacterial meningitis, we found variable levels of CBF and cerebrovascular CO(2) reactivity, a low a-v DO(2), low cerebral metabolic rates of oxygen and glucose, and a cerebral lactate efflux. In these patients...

  5. Prevalence of Central Obesity among Adults with Normal BMI and Its Association with Metabolic Diseases in Northeast China

    Science.gov (United States)

    Zhang, Peng; Wang, Rui; Gao, Chunshi; Jiang, Lingling; Lv, Xin; Song, Yuanyuan; Li, Bo

    2016-01-01

    Objectives The present study aimed to investigate the prevalence of central obesity among adults with normal BMI and its association with metabolic diseases in Jilin Province, China. Methods A population-based cross-sectional study was conducted in 2012 in Jilin Province of China. Information was collected by face to face interview. Descriptive data analysis and 95% confidence intervals (CI) of prevalence/frequency were conducted. Log-binomial regression analyses were used to find the independent factors associated with central obesity and to explore the adjusted association between central obesity and metabolic diseases among adults with normal BMI. Results Among the adult residents with normal BMI in Jilin Province, 55.6% of participants with central obesity self-assessed as normal weight and 27.0% thought their body weight were above normal. 12.7% of central obesity people took methods to lose weight, while 85.3% didn’t. Female, older people and non-manual worker had higher risk to be central obesity among adults with normal BMI. Hypertension, diabetes and hyperlipidemia were significantly associated with central obesity among adults with normal BMI, the PRs were 1.337 (1.224–1.461), 1.323 (1.193–1.456) and 1.261 (1.152–1.381) separately when adjusted for gender, age and BMI. Conclusions Hypertension, diabetes and hyperlipidemia were significantly associated with central obesity among adults with normal BMI in Jilin Province, China. The low rates of awareness and control of central obesity among adults with normal BMI should be improved by government and health department. PMID:27467819

  6. Central Role of Pyruvate Kinase in Carbon Co-catabolism of Mycobacterium tuberculosis.

    Science.gov (United States)

    Noy, Tahel; Vergnolle, Olivia; Hartman, Travis E; Rhee, Kyu Y; Jacobs, William R; Berney, Michael; Blanchard, John S

    2016-03-25

    Mycobacterium tuberculosis (Mtb) displays a high degree of metabolic plasticity to adapt to challenging host environments. Genetic evidence suggests thatMtbrelies mainly on fatty acid catabolism in the host. However,Mtbalso maintains a functional glycolytic pathway and its role in the cellular metabolism ofMtbhas yet to be understood. Pyruvate kinase catalyzes the last and rate-limiting step in glycolysis and theMtbgenome harbors one putative pyruvate kinase (pykA, Rv1617). Here we show thatpykAencodes an active pyruvate kinase that is allosterically activated by glucose 6-phosphate (Glc-6-P) and adenosine monophosphate (AMP). Deletion ofpykApreventsMtbgrowth in the presence of fermentable carbon sources and has a cidal effect in the presence of glucose that correlates with elevated levels of the toxic catabolite methylglyoxal. Growth attenuation was also observed in media containing a combination of short chain fatty acids and glucose and surprisingly, in media containing odd and even chain fatty acids alone. Untargeted high sensitivity metabolomics revealed that inactivation of pyruvate kinase leads to accumulation of phosphoenolpyruvate (P-enolpyruvate), citrate, and aconitate, which was consistent with allosteric inhibition of isocitrate dehydrogenase by P-enolpyruvate. This metabolic block could be relieved by addition of the α-ketoglutarate precursor glutamate. Taken together, our study identifies an essential role of pyruvate kinase in preventing metabolic block during carbon co-catabolism inMtb. PMID:26858255

  7. Central Role of Pyruvate Kinase in Carbon Co-catabolism of Mycobacterium tuberculosis.

    Science.gov (United States)

    Noy, Tahel; Vergnolle, Olivia; Hartman, Travis E; Rhee, Kyu Y; Jacobs, William R; Berney, Michael; Blanchard, John S

    2016-03-25

    Mycobacterium tuberculosis (Mtb) displays a high degree of metabolic plasticity to adapt to challenging host environments. Genetic evidence suggests thatMtbrelies mainly on fatty acid catabolism in the host. However,Mtbalso maintains a functional glycolytic pathway and its role in the cellular metabolism ofMtbhas yet to be understood. Pyruvate kinase catalyzes the last and rate-limiting step in glycolysis and theMtbgenome harbors one putative pyruvate kinase (pykA, Rv1617). Here we show thatpykAencodes an active pyruvate kinase that is allosterically activated by glucose 6-phosphate (Glc-6-P) and adenosine monophosphate (AMP). Deletion ofpykApreventsMtbgrowth in the presence of fermentable carbon sources and has a cidal effect in the presence of glucose that correlates with elevated levels of the toxic catabolite methylglyoxal. Growth attenuation was also observed in media containing a combination of short chain fatty acids and glucose and surprisingly, in media containing odd and even chain fatty acids alone. Untargeted high sensitivity metabolomics revealed that inactivation of pyruvate kinase leads to accumulation of phosphoenolpyruvate (P-enolpyruvate), citrate, and aconitate, which was consistent with allosteric inhibition of isocitrate dehydrogenase by P-enolpyruvate. This metabolic block could be relieved by addition of the α-ketoglutarate precursor glutamate. Taken together, our study identifies an essential role of pyruvate kinase in preventing metabolic block during carbon co-catabolism inMtb.

  8. Changes of in vivo fluxes through central metabolic pathways during the production of nystatin by Streptomyces noursei in batch culture

    DEFF Research Database (Denmark)

    Jonsbu, E.; Christensen, Bjarke; Nielsen, Jens

    2001-01-01

    of the amino acids and calculated fluxes of the central metabolism showed that changes in the primary and secondary metabolisms occurred simultaneously. Changes in the profiles for the integrated fluxes showed a decreased flux through the pentose phosphate pathway and an increased flux in the tricarboxylic...... acid cycle relative to the glucose uptake rate when the culture entered a phase with reduced specific growth rate and enhanced nystatin yield. The flux through the pentose phosphate pathway seemed to be adjusted according to the NADPH requirement during the different phases of the batch fermentation....

  9. Nutritional Manipulation of One-Carbon Metabolism: Effects on Arsenic Methylation and Toxicity

    Directory of Open Access Journals (Sweden)

    Megan N. Hall

    2012-01-01

    Full Text Available Exposure to arsenic (As through drinking water is a substantial problem worldwide. The methylation of As, a reactive metalloid, generates monomethyl- (MMA and dimethyl-arsenical (DMA species. The biochemical pathway that catalyzes these reactions, one-carbon metabolism, is regulated by folate and other micronutrients. Arsenic methylation exerts a critical influence on both its urinary elimination and chemical reactivity. Mice having the As methyltransferase null genotype show reduced urinary As excretion, increased As retention, and severe systemic toxicity. The most toxic As metabolite in vitro is MMAIII, an intermediate in the generation of DMAV, a much less toxic metabolite. These findings have raised the question of whether As methylation is a detoxification or bioactivation pathway. Results of population-based studies suggest that complete methylation of inorganic As to DMA is associated with reduced risk for As-induced health outcomes, and that nutrients involved in one-carbon metabolism, such as folate, can facilitate As methylation and elimination.

  10. Metabolism

    Science.gov (United States)

    ... also influenced by body composition — people with more muscle and less fat generally have higher BMRs. previous continue Things That Can Go Wrong With Metabolism Most of the time your metabolism works effectively ...

  11. Metabolism

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    2008255 Serum adiponectin level declines in the elderly with metabolic syndrome.WU Xiaoyan(吴晓琰),et al.Dept Geriatr,Huashan Hosp,Fudan UnivShanghai200040.Chin J Geriatr2008;27(3):164-167.Objective To investigate the correlation between ser-um adiponectin level and metabolic syndrome in the elderly·Methods Sixty-one subjects with metabolic syndrome and140age matched subjects without metabolic

  12. Trehalose 6-phosphate coordinates organic and amino acid metabolism with carbon availability.

    Science.gov (United States)

    Figueroa, Carlos M; Feil, Regina; Ishihara, Hirofumi; Watanabe, Mutsumi; Kölling, Katharina; Krause, Ursula; Höhne, Melanie; Encke, Beatrice; Plaxton, William C; Zeeman, Samuel C; Li, Zhi; Schulze, Waltraud X; Hoefgen, Rainer; Stitt, Mark; Lunn, John E

    2016-02-01

    Trehalose 6-phosphate (Tre6P) is an essential signal metabolite in plants, linking growth and development to carbon metabolism. The sucrose-Tre6P nexus model postulates that Tre6P acts as both a signal and negative feedback regulator of sucrose levels. To test this model, short-term metabolic responses to induced increases in Tre6P levels were investigated in Arabidopsis thaliana plants expressing the Escherichia coli Tre6P synthase gene (otsA) under the control of an ethanol-inducible promoter. Increased Tre6P levels led to a transient decrease in sucrose content, post-translational activation of nitrate reductase and phosphoenolpyruvate carboxylase, and increased levels of organic and amino acids. Radio-isotope ((14)CO2) and stable isotope ((13)CO2) labelling experiments showed no change in the rates of photoassimilate export in plants with elevated Tre6P, but increased labelling of organic acids. We conclude that high Tre6P levels decrease sucrose levels by stimulating nitrate assimilation and anaplerotic synthesis of organic acids, thereby diverting photoassimilates away from sucrose to generate carbon skeletons and fixed nitrogen for amino acid synthesis. These results are consistent with the sucrose-Tre6P nexus model, and implicate Tre6P in coordinating carbon and nitrogen metabolism in plants. PMID:26714615

  13. Growth-related Metabolism of the Carbon Storage Poly-3-hydroxybutyrate in Legionella pneumophila.

    Science.gov (United States)

    Gillmaier, Nadine; Schunder, Eva; Kutzner, Erika; Tlapák, Hana; Rydzewski, Kerstin; Herrmann, Vroni; Stämmler, Maren; Lasch, Peter; Eisenreich, Wolfgang; Heuner, Klaus

    2016-03-18

    Legionella pneumophila, the causative agent of Legionnaires disease, has a biphasic life cycle with a switch from a replicative to a transmissive phenotype. During the replicative phase, the bacteria grow within host cells in Legionella-containing vacuoles. During the transmissive phenotype and the postexponential (PE) growth phase, the pathogens express virulence factors, become flagellated, and leave the Legionella-containing vacuoles. Using (13)C labeling experiments, we now show that, under in vitro conditions, serine is mainly metabolized during the replicative phase for the biosynthesis of some amino acids and for energy generation. During the PE phase, these carbon fluxes are reduced, and glucose also serves as an additional carbon substrate to feed the biosynthesis of poly-3-hydroxybuyrate (PHB), an essential carbon source for transmissive L. pneumophila. Whole-cell FTIR analysis and comparative isotopologue profiling further reveal that a putative 3-ketothiolase (Lpp1788) and a PHB polymerase (Lpp0650), but not enzymes of the crotonyl-CoA pathway (Lpp0931-0933) are involved in PHB metabolism during the PE phase. However, the data also reflect that additional bypassing reactions for PHB synthesis exist in agreement with in vivo competition assays using Acanthamoeba castellannii or human macrophage-like U937 cells as host cells. The data suggest that substrate usage and PHB metabolism are coordinated during the life cycle of the pathogen. PMID:26792862

  14. Comparative study on CO2 sources in soil developed on carbonate rock and non-carbonate rock in Central Guizhou

    Institute of Scientific and Technical Information of China (English)

    黎廷宇; 王世杰; 郑乐平

    2002-01-01

    In this paper, by using concentration and carbon stable isotope the CO2 sources of soil profiles developed on limestone, dolostone and claystone basements in Central Guizhou, China are comparatively studied. The results show that CO2 concentration of soil profiles developed on different basements is different, having the following sequence: limestone>dolostone>claystone. Below the soil depth of 20 cm from the surface the ? 13C value of CO2 in soil profile developed on limestone ranges from -12.811‰ - -13.492‰(PDB), that in soil profile developed on dolostone varys from -13.212‰ - -14.271‰(PDB) and that in soil profile developed on claystone is about -20.234‰ - -21.485‰(PDB). Taking the carbon isotope of soil organic matter and carbonate rock as two isotopic endmembers, the proportion of soil CO2 generated by dissolution of carbonate rock is calculated, about 21%-25% for soil profile developed on limestone basement, 19%-21% for soil profile developed on dolostone basement. There is almost no influx of CO2 generated by the dissolution of carbonate rock in soil profile developed on claystone basement.

  15. Carbonates in mantle xenoliths from French Massif Central: inference for carbonatite-related metasomatism.

    Science.gov (United States)

    Wagner, Christiane; Deloule, Etienne

    2016-04-01

    Mantle xenoliths from the sub-continental lithospheric mantle (SCLM) frequently display evidence of metasomatism by melts or fluids of variable composition, e.g. alkali-basaltic, alkali-carbonate or carbonate melts. Carbonate-bearing mantle xenoliths are particularly interesting as highly mobile carbonate melts are likely prominent metasomatic agents of the mantle. This study presents detailed petrographic descriptions and major and trace element compositions of minerals in protogranular spinel lherzolites from the Mont Coupet occurrence (Devès province, French Massif Central), with focus on the carbonate phases to discuss their possible link to carbonatite melt. Two representative samples are described here. MC9 shows no evidence for infiltration of the host basanitic magma. Carbonates occur (1) as large (100 μm - 200 μm) anhedral crystals in interstitial pockets at triple point of primary olivine grains, (2) in a few cross-cutting veins (up to 200 μm width), (3) along grain boundaries and (4) in composite carbonate-silicate pockets from well-developed reaction zones, in which carbonates fill globular vesicles. The reaction zone contains secondary subhedral to euhedral phases: Al- and Ti-rich clinopyroxene, Ca-rich olivine, Cr-rich spinel and quenched plagioclase and relict sieved-textured primary spinel. MC2 shows carbonate-bearing thin (structures, similar to those observed in the globular vesicles from the host basanite. In sample MC9, the carbonate is an alkali-free Mg-poor calcite (XCa = 0.95 - 0.98; with 0.5 - 1.8 wt. % MgO) whatever the occurrence. In sample MC2, carbonates are Mg-richer, particularly the type 2 and 3 carbonates (XCa = 0.88 - 0.91; 3 - 5 wt. % MgO), a composition similar to that of the carbonates from the vesicles in the basanite (XCa = 0.86 - 0.88; 4 - 5 wt. % MgO). In both xenoliths, the carbonates have low REE abundances (mostly below the detection limit except La and Ce), similar to those reported for carbonates from mantle

  16. Metabolic and transcriptional response of central metabolism affected by root endophytic fungus Piriformospora indica under salinity in barley.

    Science.gov (United States)

    Ghaffari, Mohammad Reza; Ghabooli, Mehdi; Khatabi, Behnam; Hajirezaei, Mohammad Reza; Schweizer, Patrick; Salekdeh, Ghasem Hosseini

    2016-04-01

    The root endophytic fungus Piriformospora indica enhances plant adaptation to environmental stress based on general and non-specific plant species mechanisms. In the present study, we integrated the ionomics, metabolomics, and transcriptomics data to identify the genes and metabolic regulatory networks conferring salt tolerance in P. indica-colonized barley plants. To this end, leaf samples were harvested at control (0 mM NaCl) and severe salt stress (300 mM NaCl) in P. indica-colonized and non-inoculated barley plants 4 weeks after fungal inoculation. The metabolome analysis resulted in an identification of a signature containing 14 metabolites and ions conferring tolerance to salt stress. Gene expression analysis has led to the identification of 254 differentially expressed genes at 0 mM NaCl and 391 genes at 300 mM NaCl in P. indica-colonized compared to non-inoculated samples. The integration of metabolome and transcriptome analysis indicated that the major and minor carbohydrate metabolism, nitrogen metabolism, and ethylene biosynthesis pathway might play a role in systemic salt-tolerance in leaf tissue induced by the root-colonized fungus. PMID:26951140

  17. Carbon Stock Potential of Oak and Pine Forests in Garhwal Region in Indian Central Himalayas

    OpenAIRE

    Nanda Nautiyal; Vir Singh

    2013-01-01

    Oak (Quercus leucotichophora) and pine (Pinus roxburghii) are the two most dominant forest types occurring in Indian Central Himalayas. CO2 mitigation potential of these two forest types was observed in the present study. Carbon stock densities for AGTB, BB, LHG, DWS, AGSB and SOC were estimated and higher values were recorded in oak forest stands. Total carbon density estimated was 2420.54 Mg/ha for oak forest of Gopeshwar and 986.93 Mg/ha for pine forest of Nandprayag. CO2 mitigation potent...

  18. Interaction Between the Central and Peripheral Effects of Insulin in Controlling Hepatic Glucose Metabolism in the Conscious Dog

    OpenAIRE

    Ramnanan, Christopher J.; Kraft, Guillaume; Smith, Marta S.; Farmer, Ben; Neal, Doss; Williams, Phillip E.; Lautz, Margaret; Farmer, Tiffany; Donahue, E. Patrick; Cherrington, Alan D.; Edgerton, Dale S.

    2012-01-01

    The importance of hypothalamic insulin action to the regulation of hepatic glucose metabolism in the presence of a normal liver/brain insulin ratio (3:1) is unknown. Thus, we assessed the role of central insulin action in the response of the liver to normal physiologic hyperinsulinemia over 4 h. Using a pancreatic clamp, hepatic portal vein insulin delivery was increased three- or eightfold in the conscious dog. Insulin action was studied in the presence or absence of intracerebroventricularl...

  19. The PGC-1α/ERRα Axis Represses One-Carbon Metabolism and Promotes Sensitivity to Anti-folate Therapy in Breast Cancer

    Directory of Open Access Journals (Sweden)

    Étienne Audet-Walsh

    2016-02-01

    Full Text Available Reprogramming of cellular metabolism plays a central role in fueling malignant transformation, and AMPK and the PGC-1α/ERRα axis are key regulators of this process. The intersection of gene-expression and binding-event datasets for breast cancer cells shows that activation of AMPK significantly increases the expression of PGC-1α/ERRα and promotes the binding of ERRα to its cognate sites. Unexpectedly, the data also reveal that ERRα, in concert with PGC-1α, negatively regulates the expression of several one-carbon metabolism genes, resulting in substantial perturbations in purine biosynthesis. This PGC-1α/ERRα-mediated repression of one-carbon metabolism promotes the sensitivity of breast cancer cells and tumors to the anti-folate drug methotrexate. These data implicate the PGC-1α/ERRα axis as a core regulatory node of folate cycle metabolism and further suggest that activators of AMPK could be used to modulate this pathway in cancer.

  20. Epiphyte dynamics and carbon metabolism in a nutrient enriched Mediterranean seagrass ( Posidonia oceanica ) ecosystem

    Science.gov (United States)

    Apostolaki, Eugenia T.; Holmer, Marianne; Marbà, Núria; Karakassis, Ioannis

    2011-08-01

    The study aimed at examining the relationship between epiphyte dynamics and carbon metabolism in seagrass ecosystems under nutrient enrichment. Temporal variability of epiphytes and factors controlling their dynamics (i.e. environmental conditions, substratum availability, substratum stability and herbivore pressure) were assessed in a fish farm impacted and an unaffected Mediterranean seagrass ( Posidonia oceanica) meadow in the Aegean Sea (Greece). The factors controlling epiphyte dynamics responded differently to nutrient enrichment and partly interacted, rendering their cumulative effect on epiphyte load difficult to elucidate. Yet epiphytes accumulated on seagrass leaves near to the fish farm throughout the year, contributing 2 times more in above-ground biomass at cages than the control station. Reduction in substratum availability (i.e. decrease in leaf biomass) and increase in herbivore pressure affected epiphyte load, albeit their effects were not strong enough to counterbalance the effect of nutrient input from fish farm effluents. Moderate yet continuous nutrient input possibly stimulated epiphyte growth in excess of herbivory, shifting the control of epiphytes from top-down to bottom-up. Epiphyte accumulation affected carbon metabolism in the seagrass ecosystem by contributing to enhanced dissolved organic carbon (DOC) release, but seagrass loss was so acute that increased epiphyte cover could not counterbalance the decrease in community carbon production which was mainly driven by seagrass decline.

  1. PI3K: An Attractive Candidate for the Central Integration of Metabolism and Reproduction

    OpenAIRE

    Maricedes eAcosta-Martinez

    2012-01-01

    In neurons, as in a variety of other cell types, the enzyme phosphatidylinositol-3-kinase (PI3K) is a key intermediate that is common to the signaling pathways of a number of peripheral metabolic cues, including insulin and leptin, which are well known to regulate both metabolic and reproductive functions. In this article, I explore the possibility that PI3K is a key integrator of metabolic and neural signals regulating gonadotropin releasing hormone (GnRH)/luteinizing hormone (LH) release a...

  2. Comparative study on CO2 sources in soil developed on carbonate rock and non-carbonate rock in Central Guizhou

    Institute of Scientific and Technical Information of China (English)

    黎廷宇; 王世杰; 郑乐平

    2002-01-01

    In this paper, by using concentration and carbon stable isotope the.CO2 sources of soil profiles developed on limestone, dolostone and claystone basements in Central Guizhou, China are comparatively studied. The results show that CO2 concentration of soil profiles developed on different basements is different, having the following sequence: limestone>dolostone>claystone. Below the soil depth of 20 cm from the surface the δ13C value of CO2 in soil profile developed on limestone ranges from -12.811‰ - -13.492‰(PDB), that in soil profile developed on dolostone varys from -13.212‰--14.271‰(PDB) and that in soil profile developed on claystone is about -20.234‰- -21.485‰(PDB). Taking the carbon isotope of soil organic matter and carbonate rock as two isotopic endmembers, the proportion of soil C02 generated by dissolution of carbonate rock is calculated, about 21%-25% for soil profile developed on limestone basement, 19%-21% for soil profile developed on dolostone basement. There is almost no influx of

  3. A novel role for central ACBP/DBI as a regulator of long-chain fatty acid metabolism in astrocytes

    DEFF Research Database (Denmark)

    Bouyakdan, Khalil; Taïb, Bouchra; Budry, Lionel;

    2015-01-01

    Acyl-CoA-binding protein (ACBP) is a ubiquitously expressed protein that binds intracellular acyl-CoA esters. Several studies have suggested that ACBP acts as an acyl-CoA pool former and regulates long-chain fatty acids (LCFA) metabolism in peripheral tissues. In the brain, ACBP is known as Diaze......-related genes and results in intracellular FA accumulation while affecting their release. Our results support a novel role for ACBP in brain lipid metabolism. FA, fatty acids; KO, knockout; PL, phospholipids; TAG, triacylglycerol....... metabolism-related gene expression using ACBP-deficient and control mice. ACBP was mainly found in astrocytes with high expression levels in the mediobasal hypothalamus. We demonstrate that ACBP deficiency alters the central LCFA-CoA profile and impairs unsaturated (oleate, linolenate) but not saturated...... (palmitate, stearate) LCFA metabolic fluxes in hypothalamic slices and astrocyte cultures. In addition, lack of ACBP differently affects the expression of genes involved in FA metabolism in cortical versus hypothalamic astrocytes. Finally, ACBP deficiency increases FA content and impairs their release...

  4. Unusual carbonate-rich dikes and lamprophyres in Porcupine Dome, east-central Montana

    Energy Technology Data Exchange (ETDEWEB)

    Doden, A.G.; Gold, D.P. (Pennsylvania State Univ., University Park, PA (United States). Dept. of Geosciences)

    1992-01-01

    Isolated carbonate dikes and lamprophyric plugs are exposed in Porcupine dome, a Laramide structure in east-central Montana. En echelon sets of carbonate dikes strike N70E, consistent with regional lineaments and local normal faults. Individual dikes are steeply dipping, only 30--70 cm in width, and up to 1 km in length. These dikes exhibit unequivocal magmatic characteristics, including chilled margins, flow-aligned micas, multiple intrusive stages, country rock xenoliths, and local small blows'' containing well-rounded carbonate autoliths. Spatially associated with the dikes are small plugs of olivine-phlogopite-garnet-carbonate-bearing silicate rocks and a diatreme of bedded tuffs with xenoliths of country rocks. The dikes consistent primarily of calcite and dolomite, phlogopite, and opaque oxides. Although the dikes are relatively homogeneous mineralogically along strike, some chemical variations are apparent in the vicinity of the plugs/diatreme. Phlogopites and carbonates, common to both dikes and plugs, may provide a genetic link between these spatially associated intrusions. These unusual associations of dikes, plugs and diatremes are not restricted to Porcupine dome, but extend at least as far as the Grassrange - Winnett area, 100 km to the NW. The regional distribution of these small carbonatite bodies suggests a different magmatic process from typical carbonatites and alkaline complexes. The closest analogy is the carbonate dikes in the Premier Diamond Mine, South Africa.

  5. Impact of xylose and mannose on central metabolism of yeast Saccharomyces cerevisiae

    Energy Technology Data Exchange (ETDEWEB)

    Pitkaenen, J.P.

    2005-07-01

    In this study, understanding of the central metabolism was improved by quantification of metabolite concentrations, enzyme activities, protein abundances, and gene transcript concentrations. Intracellular fluxes were estimated by applying stoichiometric models of metabolism. The methods were applied in the study of yeast Saccharomyces cerevisiae in two separate projects. A xylose project aimed at improved utilization of D- xylose as a substrate for, e.g., producing biomaterial- based fuel ethanol. A mannose project studied the production of GDP-mannose from D-mannose in a strain lacking the gene for phosphomannose isomerase (PMI40 deletion). Hexose, D-glucose is the only sugar more abundant than pentose D-xylose. D-xylose is common in hardwoods (e.g. birch) and crop residues (ca. 25% of dry weight). However, S. cerevisiae is unable to utilize D- xylose without a recombinant pathway where D-xylose is converted to Dxylulose. In this study D-xylose was converted in two steps via xylitol: by D-xylose reductase and xylitol dehydrogenase encoded by XYL1 and XYL2 from Pichia stipitis, respectively. Additionally, endogenous xylulokinase (XKS1) was overexpressed in order to increase the consumption of D-xylose by enhancing the phosphorylation of D-xylulose. Despite of the functional recombinant pathway the utilization rates of D xylose still remained low. This study proposes a set of limitations that are responsible for the low utilization rates of D-xylose under microaerobic conditions. Cells compensated for the cofactor imbalance, caused by the conversion of D-xylose to D- xylulose, by increasing the flux through the oxidative pentose phosphate pathway and by shuttling NADH redox potential to mitochondrion to be oxidized in oxidative phosphorylation. However, mitochondrial NADH inhibits citrate synthase in citric acid cycle, and consequently lower flux through citric acid cycle limits oxidative phosphorylation. Further, limitations in the uptake of D- xylose, in the

  6. PI3K: An attractive candidate for the central integration of metabolism and reproduction

    Directory of Open Access Journals (Sweden)

    Maricedes eAcosta-Martinez

    2012-01-01

    Full Text Available In neurons, as in a variety of other cell types, the enzyme phosphatidylinositol-3-kinase (PI3K is a key intermediate that is common to the signaling pathways of a number of peripheral metabolic cues, including insulin and leptin, which are well known to regulate both metabolic and reproductive functions. In this article, I explore the possibility that PI3K is a key integrator of metabolic and neural signals regulating gonadotropin releasing hormone (GnRH/luteinizing hormone (LH release and explore the hypothesis that this enzyme is pivotal in many disorders where gonadotropin release is at risk. Although the mechanisms mediating the influence of metabolism and nutrition on fertility are currently unclear, the strong association between metabolic disorders and infertility is undeniable. For example, women suffering from anorectic disorders experience amenorrhea as a consequence of malnutrition-induced impairment of LH release, and at the other extreme, obesity is also commonly co-morbid with menstrual dysfunction and infertility. Impaired hypothalamic insulin and leptin receptor signaling is thought to be at the core of reproductive disorders associated with metabolic dysfunction. While low levels of leptin and insulin characterize states of negative energy balance, prolonged nutrient excess is associated with insulin and leptin resistance. Metabolic models known to alter GnRH/LH release such as diabetes, diet-induced obesity, and caloric restriction are also accompanied by impairment of PI3K signaling in insulin and leptin sensitive tissues including the hypothalamus. However, a clear link between this signaling pathway and the control of GnRH release by peripheral metabolic cues has not been established. Investigating the role of the signaling pathways shared by metabolic cues that are critical for a normal reproductive state can help identify possible targets in the treatment of metabolic and reproductive disorders such as Polycystic Ovarian

  7. Carbon dioxide emissions embodied in international trade in Central Europe between 1995 and 2008

    Directory of Open Access Journals (Sweden)

    Vlčková Jana

    2015-12-01

    Full Text Available Climate change and environmental policies are widely discussed, but much less is known about emissions embodied in goods traded internationally, and the distinction between emission producers and consumers. The carbon dioxide emissions embodied in international trade in Central European countries are subject to examination in this paper. As a result of industrial restructuring and environmental legislation, air pollution has improved significantly in Central European countries since the 1989 transition. On the other hand, economic growth has been accompanied by a rise in consumerism. Despite the increasing role of exports, the Visegrad group countries have become net importers of carbon dioxide emissions between 1995 and 2008. This seems to be the ‘standard trajectory’ of a country’s transition toward a more developed and consumption-oriented economy. The global patterns of carbon dioxide emissions embodied in manufacturing exports are also mapped, using network analysis and constructing ‘product space’. The analysis confirms that industrial re-structuring played an important role in lowering the production of carbon dioxide emissions in the Visegrad countries.

  8. Vitamin B12: one carbon metabolism, fetal growth and programming for chronic disease.

    Science.gov (United States)

    Rush, E C; Katre, P; Yajnik, C S

    2014-01-01

    This review brings together human and animal studies and reviews that examine the possible role of maternal vitamin B12 (B12) on fetal growth and its programming for susceptibility to chronic disease. A selective literature review was undertaken to identify studies and reviews that investigate these issues, particularly in the context of a vegetarian diet that may be low in B12 and protein and high in carbohydrate. Evidence is accumulating that maternal B12 status influences fetal growth and development. Low maternal vitamin B12 status and protein intake are associated with increased risk of neural tube defect, low lean mass and excess adiposity, increased insulin resistance, impaired neurodevelopment and altered risk of cancer in the offspring. Vitamin B12 is a key nutrient associated with one carbon metabolic pathways related to substrate metabolism, synthesis and stability of nucleic acids and methylation of DNA which regulates gene expression. Understanding of factors regulating maternal-fetal one carbon metabolism and its role in fetal programming of non communicable diseases could help design effective interventions, starting with maternal nutrition before conception. PMID:24219896

  9. The relationship between microbial metabolic activity and biocorrosion of carbon steel.

    Science.gov (United States)

    Dzierzewicz, Z; Cwalina, B; Chodurek, E; Wilczok, T

    1997-12-01

    The effect of metabolic activity (expressed by generation time, rate of H2S production and the activity of hydrogenase and adenosine phosphosulphate (APS)-reductase enzymes) of the 8 wild strains of Desulfovibrio desulfuricans and of their resistance to metal ions (Hg2+, Cu2+, Mn2+, Zn2+, Ni2+, Cr3+) on the rate of corrosion of carbon steel was studied. The medium containing lactate as the carbon source and sulphate as the electron acceptor was used for bacterial metabolic activity examination and in corrosive assays. Bacterial growth inhibition by metal ions was investigated in the sulphate-free medium. The rate of H2S production was approximately directly proportional to the specific activities of the investigated enzymes. These activities were inversely proportional to the generation time. The rate of microbiologically induced corrosion (MIC) of carbon steel was directly proportional to bacterial resistance to metal ions (correlation coefficient r = 0.95). The correlation between the MIC rate and the activity of enzymes tested, although weaker, was also observed (r = 0.41 for APS-reductase; r = 0.69 for hydrogenase; critical value rc = 0.30, p = 0.05, n = 40).

  10. Mitochondrial DNA Replication Defects Disturb Cellular dNTP Pools and Remodel One-Carbon Metabolism.

    Science.gov (United States)

    Nikkanen, Joni; Forsström, Saara; Euro, Liliya; Paetau, Ilse; Kohnz, Rebecca A; Wang, Liya; Chilov, Dmitri; Viinamäki, Jenni; Roivainen, Anne; Marjamäki, Päivi; Liljenbäck, Heidi; Ahola, Sofia; Buzkova, Jana; Terzioglu, Mügen; Khan, Nahid A; Pirnes-Karhu, Sini; Paetau, Anders; Lönnqvist, Tuula; Sajantila, Antti; Isohanni, Pirjo; Tyynismaa, Henna; Nomura, Daniel K; Battersby, Brendan J; Velagapudi, Vidya; Carroll, Christopher J; Suomalainen, Anu

    2016-04-12

    Mitochondrial dysfunction affects cellular energy metabolism, but less is known about the consequences for cytoplasmic biosynthetic reactions. We report that mtDNA replication disorders caused by TWINKLE mutations-mitochondrial myopathy (MM) and infantile onset spinocerebellar ataxia (IOSCA)-remodel cellular dNTP pools in mice. MM muscle shows tissue-specific induction of the mitochondrial folate cycle, purine metabolism, and imbalanced and increased dNTP pools, consistent with progressive mtDNA mutagenesis. IOSCA-TWINKLE is predicted to hydrolyze dNTPs, consistent with low dNTP pools and mtDNA depletion in the disease. MM muscle also modifies the cytoplasmic one-carbon cycle, transsulfuration, and methylation, as well as increases glucose uptake and its utilization for de novo serine and glutathione biosynthesis. Our evidence indicates that the mitochondrial replication machinery communicates with cytoplasmic dNTP pools and that upregulation of glutathione synthesis through glucose-driven de novo serine biosynthesis contributes to the metabolic stress response. These results are important for disorders with primary or secondary mtDNA instability and offer targets for metabolic therapy. PMID:26924217

  11. Toward microtesla MRI of hyperpolarized carbon-13 for real-time metabolic imaging

    CERN Document Server

    Zotev, V S; Savukov, I M; Matlashov, A N; Gómez, J J; Espy, M A

    2009-01-01

    Hyperpolarization of carbon-13 is a promising technique that has enabled MR angiography, perfusion mapping, and real-time metabolic imaging of C-13 labeled organic substances with unprecedented signal-to-noise levels. Because the hyperpolarization is performed outside an MRI scanner (using a special NMR-style hyperpolarizer), high magnetic fields of conventional MRI systems offer little advantage in terms of achievable C-13 polarization. Here we propose an ultimate low-field MRI scanner for imaging hyperpolarized C-13. It uses only microtesla-range magnetic fields and employs SQUID (superconducting quantum interference device) sensors for broadband reception of MRI signals. We present the first images acquired by SQUID-based microtesla MRI with dynamic nuclear polarization (Overhauser enhancement). We also report the first NMR spectra of C-13 at microtesla fields, including spectra of metabolically relevant sodium pyruvate, bicarbonate, and alanine. Our results demonstrate feasibility and potential of the pro...

  12. Annual benthic metabolism and organic carbon fluxes in a semi-enclosed Mediterranean bay dominated by the macroalgae Caulerpa prolifera

    OpenAIRE

    Ruiz-Halpern, Sergio; Vaquer-Sunyer, Raquel; Duarte, Carlos M.

    2014-01-01

    Coastal areas play an important role on carbon cycling. Elucidating the dynamics on the production, transport, and fate of organic carbon (OC) is relevant to gain a better understanding on the role coastal areas play in the global carbon budget. Here, we assess the metabolic status and associated OC fluxes of a semi-enclosed Mediterranean bay supporting a meadow of Caulerpa prolifera. We test whether the EDOC pool is a significant component of the OC pool and associated fluxes in this ecosyst...

  13. Central and Metabolic Effects of High Fructose Consumption: Evidence from Animal and Human Studies

    OpenAIRE

    Alexandra Stoianov; Khosrow Adeli

    2014-01-01

    Fructose consumption has increased dramatically in the last 40 years, and its role in the pathogenesis of the metabolic syndrome has been implicated by many studies. It is most often encountered in the diet as sucrose (glucose and fructose) or high-fructose corn syrup (55% fructose). At high levels, dietary exposure to fructose triggers a series of metabolic changes originating in the liver, leading to hepatic steatosis, hypertriglyceridemia, insulin resistance, and decreased leptin sensitivi...

  14. Central nervous system: a conductor orchestrating metabolic regulations harmed by both hyperglycaemia and hypoglycaemia.

    OpenAIRE

    Scheen, André

    2010-01-01

    Recent evidence suggests that the brain has a key role in the control of energy metabolism, body fat content and glucose metabolism. Neuronal systems, which regulate energy intake, energy expenditure, and endogenous glucose production, sense and respond to input from hormonal and nutrient-related signals that convey information regarding both body energy stores and current energy availability. In response to this input, adaptive changes occur that promote energy homeostasis and the maintenanc...

  15. Inorganic Carbon Turnover caused by Digestion of Carbonate Sands and Metabolic Activity of Holothurians

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, Kenneth; Silverman, Jacob; Kravitz, Benjamin S.; Rivlin, Tanya; Schneider-Mor, Aya; Barbosa, Sergio; Byrne, Maria; Caldeira, Ken

    2013-11-20

    Recent measurements have shown that holothurians (sea cucumbers) play an important role in the cycling of CaCO3 in tropical coral reef systems through ingestion and processing of carbonate sediment. In this study inorganic additional aspects of carbon turnover were determined in laboratory incubations of Holothuria atra, H. leucospilota and Stichopus herrmanni from One Tree Reef, Great Barrier Reef. The pH values of the gut lumen ranged from 6.1 to 6.7 in animals with empty digestive tracts as opposed to 7.0 to 7.6 when digestive tracts were filled with sediment. Empty gut volume estimates for H. atra and S. herrmanni were 36 ± 4 mL and 151 ± 14 mL, respectively. Based on these measurements it is estimated that these species process 19 ± 2kg and 80 ± 7kg CaCO3 sand yr-1 per individual, respectively. The annual dissolution rates of H. atra and S. herrmanni of 6.5±1.9g and 9.6±1.4g, respectively, suggest that 0.05±0.02% and 0.1±0.02% of the CaCO3 processed through their gut annually is dissolved. During the incubations the CaCO3 dissolution was 0.07±0.01%, 0.04±0.01% and 0.21±0.05% of the fecal casts for H. atra, H. leucospilota and S. herrmanni, respectively. The CaCO3 saturation state for both aragonite and calcite minerals during laboratory incubations decreased markedly due to a greater increase in dissolved inorganic carbon (DIC) relative to total alkalinity (AT) as a result of respiration by the animals. Our results support the hypothesis that deposit feeders such as sea cucumbers play an important ecological role in the coral reef CaCO3 cycle.

  16. Untangling metabolic and spatial interactions of stress tolerance in plants. 1. Patterns of carbon metabolism within leaves.

    Science.gov (United States)

    Biel, Karl Y; Fomina, Irina R; Nazarova, Galina N; Soukhovolsky, Vladislav G; Khlebopros, Rem G; Nishio, John N

    2010-09-01

    The localization of the key photoreductive and oxidative processes and some stress-protective reactions within leaves of mesophytic C(3) plants were investigated. The role of light in determining the profile of Rubisco, glutamate oxaloacetate transaminase, catalase, fumarase, and cytochrome-c-oxidase across spinach leaves was examined by exposing leaves to illumination on either the adaxial or abaxial leaf surfaces. Oxygen evolution in fresh paradermal leaf sections and CO(2) gas exchange in whole leaves under adaxial or abaxial illumination was also examined. The results showed that the palisade mesophyll is responsible for the midday depression of photosynthesis in spinach leaves. The photosynthetic apparatus was more sensitive to the light environment than the respiratory apparatus. Additionally, examination of the paradermal leaf sections by optical microscopy allowed us to describe two new types of parenchyma in spinach-pirum mesophyll and pillow spongy mesophyll. A hypothesis that oxaloacetate may protect the upper leaf tissue from the destructive influence of active oxygen is presented. The application of mathematical modeling shows that the pattern of enzymatic distribution across leaves abides by the principle of maximal ecological utility. Light regulation of carbon metabolism across leaves is discussed.

  17. A Large Metabolic Carbon Ccontribution to the δ13C Record in Marine Aragonitic Bivalve Shells

    Science.gov (United States)

    Gillikin, D. P.; Lorrain, A.; Dehairs, F.

    2006-12-01

    The stable carbon isotopic signature archived in bivalve shells was originally thought to record the δ13C of seawater dissolved inorganic carbon (δ13C-DIC). However, more recent studies have shown that the incorporation of isotopically light metabolic carbon (M) significantly affects the δ13C signal recorded in biogenic carbonates. To assess the M contribution to Mercenaria mercenaria shells collected in North Carolina, USA, we sampled seawater δ13C-DIC, tissue, hemolymph and shell δ13C. We found up to a 4‰ decrease through ontogeny in shell δ13C in a 23 year old individual. There was no correlation between shell height or age and tissue δ13C. Thus, the ontogenic decrease observed in the shell δ13C could not be attributed to changes in food sources as the animal ages leading to more negative metabolic CO2, since this would require a negative relationship between tissue δ13C and shell height. Hemolymph δ13C, on the other hand, did exhibit a negative relationship with height, but the δ13C values were more positive than expected, indicating that hemolymph may not be a good proxy of extrapallial fluid δ13C. Nevertheless, the hemolymph data indicate that respired CO2 does influence the δ13C of internal fluids and that the amount of respired CO2 is related to the age of the bivalve. The percent metabolic C incorporated into the shell (%M) was significantly higher (up to 37%) than has been found in other bivalve shells, which usually contain less than 10 %M. Attempts to use shell biometrics to predict %M could not explain more than ~60% of the observed variability. Moreover, there were large differences in the %M between different sites. Thus, the metabolic effect on shell δ13C cannot easily be accounted for to allow reliable δ13C-DIC reconstructions. However, there does seem to be a common effect of size, as all sites had indistinguishable slopes between the %M and shell height (+0.19% per mm of shell height).

  18. Polyol synthesis in Aspergillus niger : influence of oxygen availability, carbon and nitrogen sources on the metabolism

    DEFF Research Database (Denmark)

    Diano, Audrey; Bekker-Jensen, S; Dynesen, Jens Østergaard;

    2006-01-01

    viscosity and herebya decrease in masstransfer, especially oxygen transfer. The consequence was a decrease in DOT and the occurrence of a switch between fully aerobic conditions and oxygen-limited conditions. Metabolite quantification showed that polyols were the main metabolic products formed......, erythritol, xylitol, and arabitol were produced as carbon storage compounds when the flux through the PP pathway exceeded the need in ribulose-5-phosphate for the biomass synthesis. Glycerol, erythritol, and xylitol seem to be involved in osmoregulation. Mannitol was produced when the catabolic reduction...

  19. Suppression of the External MitochondrialNADPH Dehydrogenase, NDB1, in Arabidopsisthaliana Affects Central Metabolism andVegetative Growth

    Institute of Scientific and Technical Information of China (English)

    2014-01-01

    Ca2+-dependent oxidation of cytosolic NADPH is mediated by NDB1, which is an external type II NADPHdehydrogenase in the plant mitochondrial electron transport chain. Using RNA interference, the NDB1 transcript wassuppressed by 80% in Arabidopsis thaliana plants, and external Ca2+-dependent NADPH dehydrogenase activity becameundetectable in isolated mitochondria. This was linked to a decreased level of NADP+ in rosettes of the transgenic lines.Sterile-grown transgenic seedlings displayed decreased growth specifically on glucose, and respiratory metabolism of 14C-glucose was increased. On soil, NDBl-suppressing plants had a decreased vegetative biomass, but leaf maximumquantum efficiency of photosystem Ⅱ and CO2 assimilation rates, as well as total respiration, were similar to the wild-type. The in vivo alternative oxidase activity and capacity were also similar in all genotypes. Metabolic profiling revealeddecreased levels of sugars, citric acid cycle intermediates, and amino acids in the transgenic lines. The NDBl-suppressioninduced transcriptomic changes associated with protein synthesis and glucosinolate and jasmonate metabolism. Thetranscriptomic changes also overlapped with changes observed in a mutant lacking ABAINSENSITIVE4 and in A. thalianaoverexpressing stress tolerance genes from rice. The results thus indicate that A. thaliana NDB1 modulates NADP(H)reduction levels, which in turn affect central metabolism and growth, and interact with defense signaling.

  20. Glutamate metabolism of astrocytes during hyperbaric oxygen exposure and its effects on central nervous system oxygen toxicity.

    Science.gov (United States)

    Chen, Yu-Liang; Li, Dan; Wang, Zhong-Zhuang; Xu, Wei-Gang; Li, Run-Ping; Zhang, Jun-Dong

    2016-01-20

    Hyperbaric oxygen (HBO) has been used widely in many underwater missions and clinical work. However, exposure to extremely high oxygen pressure may cause central nervous system oxygen toxicity (CNS-OT). The regulation of astrocyte glutamate metabolism is closely related to epilepsy. This study aimed to observe the effects of HBO exposure on glutamate metabolism in astrocytes and confirm the role of glutamate metabolism in CNS-OT. Anesthetized rats were exposed to 5 atmosphere absolute HBO for 80 min and microdialysis samples of brain interstitial fluid were continuously collected. Extracellular glutamate and glutamine concentrations were also detected. Freely moving rats were exposed to HBO of the same pressure for 20 min and glutamine synthetase (GS) activity in brain tissues was measured. Finally, we observed the effects of different doses of drugs related to glutamate metabolism on the latency of CNS-OT. Results showed that HBO exposure significantly increased glutamate content, whereas glutamine content was significantly reduced. Moreover, HBO exposure significantly reduced GS activity. Glutamate transporter-1 (GLT-1) selective antagonist ceftriaxone prolonged CNS-OT latency, whereas GLT-1 selective inhibitor dihydrokainate shortened CNS-OT latency. In summary, HBO exposure improved glutamate concentration and reduced glutamine concentration by inhibition of GS activity. GLT-1 activation also participated in the prevention of HBO-induced CNS-OT. Our research will provide a potential new target to terminate or attenuate CNS-OT. PMID:26619231

  1. 'Rod and ring' formation from IMP dehydrogenase is regulated through the one-carbon metabolic pathway.

    Science.gov (United States)

    Calise, S John; Purich, Daniel L; Nguyen, Thuy; Saleem, Dania A; Krueger, Claire; Yin, Joyce D; Chan, Edward K L

    2016-08-01

    'Rods and rings' (RRs) are conserved, non-membrane-bound intracellular polymeric structures composed, in part, of inosine monophosphate dehydrogenase (IMPDH), a key enzyme leading to GMP and GTP biosynthesis. RR formation is induced by IMPDH inhibitors as well as glutamine deprivation. They also form upon treatment of cells with glutamine synthetase inhibitors. We now report that depriving cells of serine and glycine promotes RR formation, and we have traced these effects to dihydrofolate reductase (DHFR) and serine hydroxymethyltransferase-2 (SHMT2), pivotal enzymes in one-carbon metabolism and nucleotide biosynthesis. RR assembly is likewise induced upon DHFR inhibition by methotrexate or aminopterin as well as siRNA-mediated knockdown of DHFR or SHMT2. Because RR assembly occurs when guanine nucleotide biosynthesis is inhibited, and because RRs rapidly disassemble after the addition of guanine nucleotide precursors, RR formation might be an adaptive homeostatic mechanism, allowing IMPDH to sense changes in the one-carbon folate pathway. PMID:27343244

  2. Metabolism

    Science.gov (United States)

    ... a particular food provides to the body. A chocolate bar has more calories than an apple, so ... More Common in People With Type 1 Diabetes Metabolic Syndrome Your Child's Weight Healthy Eating Endocrine System Blood ...

  3. A direct evidence for high carbon dioxide and radon-222 discharge in Central Nepal

    International Nuclear Information System (INIS)

    Gas discharges have been identified at the Syabru-Bensi hot springs, located at the front of the High Himalaya in Central Nepal, in the Main Central Thrust zone. The hot spring waters are characterized by a temperature reaching 61 C, high salinity, high alkalinity and δ13C varying from +0. 7 parts per thousand to +4. 8 parts per thousand. The gas is mainly dry carbon dioxide, with a δ13C of -0. 8 parts per thousand. The diffuse carbon dioxide flux, mapped by the accumulation chamber method, reached a value of 19000 g m-2day-1, which is comparable with values measured on active volcanoes. Similar values have been observed over a two-year time interval and the integral around the main gas discharge amounts to 0. 25 ± 0. 07 mol s-1, or 350 ± 100 ton a-1. The mean radon-222 concentration in spring water did not exceed 2. 5 Bq L-1, exponentially decreasing with water temperature. In contrast, in gas bubbles collected in the water or in the dry gas discharges, the radon concentration varied from 16 000 to 41000 Bq m-3. In the soil, radon concentration varied from 25000 to more than 50000 Bq m-3. Radon flux, measured at more than fifty points, reached extreme values, larger than 2 Bq m-2s-1, correlated to the larger values of the carbon dioxide flux. Our direct observation confirms previous studies which indicated large degassing in the Himalaya. The proposed understanding is that carbon dioxide is released at mid-crustal depth by metamorphic reactions within the Indian basement, transported along pre-existing faults by meteoric hot water circulation, and degassed before reaching surface. This work, first, confirms that further studies should be undertaken to better constrain the carbon budget of the Himalaya, and, more generally, the contribution of mountain building to the global carbon balance. Furthermore, the evidenced gas discharges provide a unique natural laboratory for methodological studies, and appear particularly important to study as a function of time

  4. A direct evidence for high carbon dioxide and radon-222 discharge in Central Nepal

    Energy Technology Data Exchange (ETDEWEB)

    Perrier, F.; Byrdina, S. [Inst Phys Globe, UMR 7154, Equipe Geomagnetisme, F-75005 Paris (France); Univ Paris Diderot, F-75005 Paris (France); Richon, P.; Bollinger, L.; Bureau, S. [CEA Bruyeres le Chatel, DIF, Dept Anal Surveillance Environm, 91 (France); Richon, P. [Inst Phys Globe, UMR 7154, Equipe Geol Syst Volcan, F-75005 Paris (France); France-Lanord, Ch. [CNRS, Ctr Rech Petrog and Geochim, F-54501 Vandoeuvre Les Nancy (France); Rajaure, S.; Koirala, Bharat Prasad; Shrestha, Prithvi Lal; Gautam, Umesh Prasad; Tiwari, Dilli Ram; Sapkota, Soma Nath [Natl Seism Ctr, Dept Mines and Geol, Kathmandu (Nepal); Revil, A. [Colorado Sch Mines, Dept Geophys, Golden, CO 80401 (United States); Revil, A. [Univ Savoie, Equipe Volcans, CNRS, LGIT, UMR 5559, Chambery (France); Contraires, S. [Inst Phys Globe, Equipe Geomat and Environm, F-75005 Paris (France)

    2009-02-15

    Gas discharges have been identified at the Syabru-Bensi hot springs, located at the front of the High Himalaya in Central Nepal, in the Main Central Thrust zone. The hot spring waters are characterized by a temperature reaching 61 C, high salinity, high alkalinity and {delta}{sup 13}C varying from +0. 7 parts per thousand to +4. 8 parts per thousand. The gas is mainly dry carbon dioxide, with a {delta}{sup 13}C of -0. 8 parts per thousand. The diffuse carbon dioxide flux, mapped by the accumulation chamber method, reached a value of 19000 g m{sup -2}day{sup -1}, which is comparable with values measured on active volcanoes. Similar values have been observed over a two-year time interval and the integral around the main gas discharge amounts to 0. 25 {+-} 0. 07 mol s{sup -1}, or 350 {+-} 100 ton a{sup -1}. The mean radon-222 concentration in spring water did not exceed 2. 5 Bq L{sup -1}, exponentially decreasing with water temperature. In contrast, in gas bubbles collected in the water or in the dry gas discharges, the radon concentration varied from 16 000 to 41000 Bq m{sup -3}. In the soil, radon concentration varied from 25000 to more than 50000 Bq m{sup -3}. Radon flux, measured at more than fifty points, reached extreme values, larger than 2 Bq m{sup -2}s{sup -1}, correlated to the larger values of the carbon dioxide flux. Our direct observation confirms previous studies which indicated large degassing in the Himalaya. The proposed understanding is that carbon dioxide is released at mid-crustal depth by metamorphic reactions within the Indian basement, transported along pre-existing faults by meteoric hot water circulation, and degassed before reaching surface. This work, first, confirms that further studies should be undertaken to better constrain the carbon budget of the Himalaya, and, more generally, the contribution of mountain building to the global carbon balance. Furthermore, the evidenced gas discharges provide a unique natural laboratory for

  5. Linking carbon storage with functional diversity in tropical rainforest in the central Congo Basin

    Science.gov (United States)

    Verbeeck, Hans; Kearsley, Elizabeth; Bauters, Marijn; Beeckman, Hans; Huygens, Dries; Steppe, Kathy; Boeckx, Pascal

    2015-04-01

    This presentation will show an overview of results of the COBIMFO project (Congo basin integrated monitoring for forest carbon mitigation and biodiversity). In the framework of this project we have established 21 permanent 1 ha sampling plots in different forest types in the Yangambi reserve. This UNESCO Man and Biosphere reserve has an area of more than 6000 km² and is located in the heart of the Congo Basin near the Yangambi research station (DR Congo). Analysis of the inventory data of these plots revealed that carbon stocks in mature forests in this area of the Congo Basin are significantly lower (24%) than stocks recorded in the outer regions of the basin. These lower stocks are attributed to a lower maximal tree height (Kearsley et al. 2013). In addition to the carbon inventories we collected leaf and wood samples on all species within 95% basal area of each of the Yangambi plots. A total of 995 individuals were sampled, covering 123 tree species. On the samples we measured 15 traits related to leaf and wood morphology and functioning. In the presented study, relationships between the observed functional diversity and biomass are analysed. One of the remarkable results of our analysis is that species with a high functional distinctiveness have a low contribution to the basal area and the carbon stocks. In contrast, species with a high contribution to the carbon stock have a low contribution to the functional diversity. Similar patterns have been observed elsewhere (e.g. Amazon basin), but are now for the first time confirmed for central African rainforest. Finally, we also present the first results of an analysis of carbons stocks and functional diversity in tropical plantations from a unique 70-years old tree diversity experiment that was established during the colonial period at the Yangambi research station. Kearsley, E., de Haulleville, T., Hufkens, K., Kidimbu, A., Toirambe, B., Baert, G., Huygens, D., Kebede, Y., Defourny, P., Bogaert, J., Beeckman, H

  6. Carbon Stock Potential of Oak and Pine Forests in Garhwal Region in Indian Central Himalayas

    Directory of Open Access Journals (Sweden)

    Nanda Nautiyal

    2013-05-01

    Full Text Available Oak (Quercus leucotichophora and pine (Pinus roxburghii are the two most dominant forest types occurring in Indian Central Himalayas. CO2 mitigation potential of these two forest types was observed in the present study. Carbon stock densities for AGTB, BB, LHG, DWS, AGSB and SOC were estimated and higher values were recorded in oak forest stands. Total carbon density estimated was 2420.54 Mg/ha for oak forest of Gopeshwar and 986.93 Mg/ha for pine forest of Nandprayag. CO2 mitigation potential of oak forest of Gopeshwar was recorded to be 8,713.94 CO2e and of pine forests 3552.95 CO2e.

  7. Carbon Uptake and the Metabolism and Transport of Lipids in an Arbuscular Mycorrhiza1

    Science.gov (United States)

    Pfeffer, Philip E.; Douds, David D.; Bécard, Guillaume; Shachar-Hill, Yair

    1999-01-01

    Both the plant and the fungus benefit nutritionally in the arbuscular mycorrhizal symbiosis: The host plant enjoys enhanced mineral uptake and the fungus receives fixed carbon. In this exchange the uptake, metabolism, and translocation of carbon by the fungal partner are poorly understood. We therefore analyzed the fate of isotopically labeled substrates in an arbuscular mycorrhiza (in vitro cultures of Ri T-DNA-transformed carrot [Daucus carota] roots colonized by Glomus intraradices) using nuclear magnetic resonance spectroscopy. Labeling patterns observed in lipids and carbohydrates after substrates were supplied to the mycorrhizal roots or the extraradical mycelium indicated that: (a) 13C-labeled glucose and fructose (but not mannitol or succinate) are effectively taken up by the fungus within the root and are metabolized to yield labeled carbohydrates and lipids; (b) the extraradical mycelium does not use exogenous sugars for catabolism, storage, or transfer to the host; (c) the fungus converts sugars taken up in the root compartment into lipids that are then translocated to the extraradical mycelium (there being little or no lipid synthesis in the external mycelium); and (d) hexose in fungal tissue undergoes substantially higher fluxes through an oxidative pentose phosphate pathway than does hexose in the host plant. PMID:10364411

  8. Expression of human dopamine receptor in potato (Solanum tuberosum results in altered tuber carbon metabolism

    Directory of Open Access Journals (Sweden)

    Świędrych Anna

    2005-02-01

    Full Text Available Abstract Background Even though the catecholamines (dopamine, norepinephrine and epinephrine have been detected in plants their role is poorly documented. Correlations between norepinephrine, soluble sugars and starch concentration have been recently reported for potato plants over-expressing tyrosine decarboxylase, the enzyme mediating the first step of catecholamine synthesis. More recently norepinephrine level was shown to significantly increase after osmotic stress, abscisic acid treatment and wounding. Therefore, it is possible that catecholamines might play a role in plant stress responses by modulating primary carbon metabolism, possibly by a mechanism similar to that in animal cells. Since to date no catecholamine receptor has been identified in plants we transformed potato plants with a cDNA encoding human dopamine receptor (HD1. Results Tuber analysis of transgenic plants revealed changes in the activities of key enzymes mediating sucrose to starch conversion (ADP-glucose phosphorylase and sucrose synthase and sucrose synthesis (sucrose phosphate synthase leading to altered content of both soluble sugars and starch. Surprisingly the catecholamine level measured in transgenic plants was significantly increased; the reason for this is as yet unknown. However the presence of the receptor affected a broader range of enzyme activities than those affected by the massive accumulation of norepinephrine reported for plants over-expressing tyrosine decarboxylase. Therefore, it is suggested that the presence of the exogenous receptor activates catecholamine cAMP signalling in plants. Conclusions Our data support the possible involvement of catecholamines in regulating plant carbon metabolism via cAMP signalling pathway.

  9. Seasonal variations of dissolved organic carbon in precipitation over urban and forest sites in central Poland.

    Science.gov (United States)

    Siudek, Patrycja; Frankowski, Marcin; Siepak, Jerzy

    2015-07-01

    Spatial and temporal variability of carbon species in rainwater (bulk deposition) was studied for the first time at two sites located in urban area of Poznań City and protected woodland area (Jeziory), in central Poland, between April and December 2013. The mean concentration of total carbon (TC) for the first site was 5.86 mg L(-1), whereas for the second, 5.21 mg L(-1). Dissolved organic carbon (DOC) concentration accounted for, on average, 87 and 91 % of total carbon in precipitation at urban and non-urban sites, respectively. Significant changes in TC concentrations in rainwater were observed at both sites, indicating that atmospheric transformation, transport, and removal mechanisms of carbonaceous particles were affected by seasonal fluctuations in biogenic/anthropogenic emission and meteorological conditions (i.e., precipitation height and type, atmospheric transport). During the warm season, the DOC concentration in rainwater was mostly influenced by mixed natural and anthropogenic sources. In contrast, during the cold season, the DOC concentration significantly increased mainly as a result of anthropogenic activities, i.e., intensive coal combustion, domestic wood burning, high-temperature processes, etc. In addition, during the winter measurements, significant differences in mean DOC concentration (Kruskal-Wallis test, p urban and non-urban sites. These data imply that carbonaceous compounds are of crucial importance in atmospheric chemistry and should be considered as an important parameter while considering wet deposition, reactions with different substances, especially over polluted environments.

  10. Dust, Elemental Carbon and Other Impurities on Central Asian Glaciers: Origin and Radiative Forcing

    Science.gov (United States)

    Schmale, J.; Flanner, M.; Kang, S.; Sprenger, M.; Zhang, Q.; Li, Y.; Guo, J.; Schwikowski, M.

    2015-12-01

    In Central Asia, more than 60 % of the population depends on water stored in glaciers and mountain snow. While temperature, precipitation and dynamic processes are key drivers of glacial change, deposition of light absorbing impurities such as mineral dust and black carbon can lead to accelerated melting through surface albedo reduction. Here, we discuss the origin of deposited mineral dust and black carbon and their impacts on albedo change and radiative forcing (RF). 218 snow samples were taken from 13 snow pits on 4 glaciers, Abramov (Pamir), Suek, Glacier No. 354 and Golubin (Tien Shan), representing deposition between summer 2012 and 2014. They were analyzed for elemental and organic carbon by a thermo-optical method, mineral dust by gravimetry, and iron by ICP-MS. Back trajectory ensembles were released every 6 hours with the Lagranto model for the covered period at all sites. Boundary layer "footprints" were calculated to estimate general source regions and combined with MODIS fire counts for potential fire contributions. Albedo reduction due to black carbon and mineral dust was calculated with the Snow-Ice-Aerosol-Radiative model (SNICAR), and surface spectral irradiances were derived from atmospheric radiative transfer calculations to determine the RF under clear-sky and all sky conditions using local radiation measurements. Dust contributions came from Central Asia, the Arabian Peninsula, the Sahara and partly the Taklimakan. Fire contributions were higher in 2014 and generally came from the West and North. We find that EC exerts roughly 3 times more RF than mineral dust in fresh and relatively fresh snow (~5 W/m2) and up to 6 times more in snow that experienced melting (> 10 W/m2) even though EC concentrations (average per snow pit from 90 to 700 ng/g) were up to two orders of magnitude lower than mineral dust (10 to 140 μg/g).

  11. Seasonal Variation of Carbon Metabolism in the Cambial Zone of Eucalyptus grandis.

    Science.gov (United States)

    Budzinski, Ilara G F; Moon, David H; Lindén, Pernilla; Moritz, Thomas; Labate, Carlos A

    2016-01-01

    Eucalyptus species are the most widely hardwood planted in the world. It is one of the successful examples of commercial forestry plantation in Brazil and other tropical and subtropical countries. The tree is valued for its rapid growth, adaptability and wood quality. Wood formation is the result of cumulative annual activity of the vascular cambium. This cambial activity is generally related to the alternation of cold and warm, and/or dry and rainy seasons. Efforts have focused on analysis of cambial zone in response to seasonal variations in trees from temperate zones. However, little is known about the molecular changes triggered by seasonal variations in trees from tropical countries. In this work we attempted to establish a global view of seasonal alterations in the cambial zone of Eucalyptus grandis Hill ex Maiden, emphasizing changes occurring in the carbon metabolism. Using transcripts, proteomics and metabolomics we analyzed the tissues harvested in summer-wet and winter-dry seasons. Based on proteomics analysis, 70 proteins that changed in abundance were successfully identified. Transcripts for some of these proteins were analyzed and similar expression patterns were observed. We identified 19 metabolites differentially abundant. Our results suggest a differential reconfiguration of carbon partioning in E. grandis cambial zone. During summer, pyruvate is primarily metabolized via ethanolic fermentation, possibly to regenerate NAD(+) for glycolytic ATP production and cellular maintenance. However, in winter there seems to be a metabolic change and we found that some sugars were highly abundant. Our results revealed a dynamic change in E. grandis cambial zone due to seasonality and highlight the importance of glycolysis and ethanolic fermentation for energy generation and maintenance in Eucalyptus, a fast growing tree. PMID:27446160

  12. Implications of central obesity-related variants in LYPLAL1, NRXN3, MSRA, and TFAP2B on quantitative metabolic traits in adult Danes

    DEFF Research Database (Denmark)

    Bille, Dorthe S; Banasik, Karina; Justesen, Johanne M;

    2011-01-01

    diabetes, and central and general overweight and obesity. Methodology/Principal Findings The four variants were genotyped in Danish individuals using KASPar®. Quantitative metabolic traits were examined in a population-based sample (n = 6,038) and WC and BMI were furthermore analyzed in a combined study......-binding protein 2 beta (TFAP2B) associate with measures of central obesity. To elucidate potential underlying phenotypes we aimed to investigate whether these variants associated with: 1) quantitative metabolic traits, 2) anthropometric measures (waist circumference (WC), waist-hip ratio, and BMI), or 3) type 2...... investigating quantitative metabolic traits. None of the variants influenced the prevalence of type 2 diabetes. Conclusion/Significance We demonstrate that several of the central obesity-associated variants in LYPLAL1, NRXN3, MSRA, and TFAP2B associate with metabolic and anthropometric traits in Danish adults...

  13. Reciprocal regulation of protein synthesis and carbon metabolism for thylakoid membrane biogenesis.

    Directory of Open Access Journals (Sweden)

    Alexandra-Viola Bohne

    Full Text Available Metabolic control of gene expression coordinates the levels of specific gene products to meet cellular demand for their activities. This control can be exerted by metabolites acting as regulatory signals and/or a class of metabolic enzymes with dual functions as regulators of gene expression. However, little is known about how metabolic signals affect the balance between enzymatic and regulatory roles of these dual functional proteins. We previously described the RNA binding activity of a 63 kDa chloroplast protein from Chlamydomonas reinhardtii, which has been implicated in expression of the psbA mRNA, encoding the D1 protein of photosystem II. Here, we identify this factor as dihydrolipoamide acetyltransferase (DLA2, a subunit of the chloroplast pyruvate dehydrogenase complex (cpPDC, which is known to provide acetyl-CoA for fatty acid synthesis. Analyses of RNAi lines revealed that DLA2 is involved in the synthesis of both D1 and acetyl-CoA. Gel filtration analyses demonstrated an RNP complex containing DLA2 and the chloroplast psbA mRNA specifically in cells metabolizing acetate. An intrinsic RNA binding activity of DLA2 was confirmed by in vitro RNA binding assays. Results of fluorescence microscopy and subcellular fractionation experiments support a role of DLA2 in acetate-dependent localization of the psbA mRNA to a translation zone within the chloroplast. Reciprocally, the activity of the cpPDC was specifically affected by binding of psbA mRNA. Beyond that, in silico analysis and in vitro RNA binding studies using recombinant proteins support the possibility that RNA binding is an ancient feature of dihydrolipoamide acetyltransferases. Our results suggest a regulatory function of DLA2 in response to growth on reduced carbon energy sources. This raises the intriguing possibility that this regulation functions to coordinate the synthesis of lipids and proteins for the biogenesis of photosynthetic membranes.

  14. Metabolic Effect of Estrogen Receptor Agonists on Breast Cancer Cells in the Presence or Absence of Carbonic Anhydrase Inhibitors

    Directory of Open Access Journals (Sweden)

    Anissa Belkaid

    2016-05-01

    Full Text Available Metabolic shift is one of the major hallmarks of cancer development. Estrogen receptor (ER activity has a profound effect on breast cancer cell growth through a number of metabolic changes driven by its effect on transcription of several enzymes, including carbonic anhydrases, Stearoyl-CoA desaturase-1, and oncogenes including HER2. Thus, estrogen receptor activators can be expected to lead to the modulation of cell metabolism in estrogen receptor positive cells. In this work we have investigated the effect of 17β-estradiol, an ER activator, and ferulic acid, a carbonic anhydrase inhibitor, as well as ER activator, in the absence and in the presence of the carbonic anhydrase inhibitor acetazolamide on the metabolism of MCF7 cells and MCF7 cells, stably transfected to express HER2 (MCF7HER2. Metabolic profiles were studied using 1D and 2D metabolomic Nuclear Magnetic Resonance (NMR experiments, combined with the identification and quantification of metabolites, and the annotation of the results in the context of biochemical pathways. Overall changes in hydrophilic metabolites were largest following treatment of MCF7 and MC7HER2 cells with 17β-estradiol. However, the carbonic anhydrase inhibitor acetazolamide had the largest effect on the profile of lipophilic metabolites.

  15. Carbon isotope ratios in crassulacean Acid metabolism plants: seasonal patterns from plants in natural stands.

    Science.gov (United States)

    Szarek, S R

    1976-09-01

    A year round study of photosynthesis and carbon isotope fractionation was conducted with plants of Opuntia phaeacantha Engelm. and Yucca baccata Torr. occurring in natural stands at elevations of 525, 970, 1450 and 1900 m. Plant water potentials and the daytime pattern of (14)CO(2) photosynthesis were similar for all cacti along the elevational gradient, despite significant differences in temperature regime and soil water status. Carbon isotope ratios of total tissue and soluble extract fractions were relatively constant throughtout the entire year. Additionally, the sigma(13)C values were similar in all plants of the same species along the elevational gradient, i.e. -12.5 +/- 0.86 per thousand for O. phaeacantha and -15.7 +/- 0.95 per thousand for Y. baccata. The results of this study indicate Crassulacean acid metabolism predominates as the major carbon pathway of these plants, which do not facultatively utilize the reductive pentose phosphate cycle of photosynthesis as the primary carboxylation reaction. PMID:16659680

  16. The activated sludge metabolic characteristics changing sole carbon source from readily biodegradable acetate to toxic phenol.

    Science.gov (United States)

    Wu, Changyong; Zhou, Yuexi; Song, Jiamei

    2016-01-01

    A sequencing batch reactor was used to investigate the effect of carbon sources on the metabolism of activated sludge. Acetate and phenol, with the chemical oxygen demand (COD) of 330-350 mg L(-1), was used as the carbon source in Periods I and II, respectively. Acetate decreased in the initial 120 min with the intracellular storage materials (XSTO), extracellular polymeric substances (EPS), and the soluble microbial products (SMP) accumulating to 131.0 mg L(-1), 347.5 mg L(-1), and 35.5 mg L(-1), respectively. Then, XSTO and EPS decreased to 124.5 mg L(-1) and 340.0 mg L(-1), respectively, in the following 120 min. When acetate was replaced by phenol, it could not be used at the beginning due to its toxicity. The XSTO decreased from 142 mg L(-1) to 54.6 mg L(-1) during the aeration period. The EPS had a significant increase, with the highest value of 618.1 mg L(-1), which then decreased to 245.6 mg L(-1) at 240 min. The phenol was gradually degraded with the acclimation and it can be fully degraded 18 d later. Meanwhile, the usage ratio of the internal carbon source decreased. The effluent SMP in Period II was 1.7 times that in Period I.

  17. The activated sludge metabolic characteristics changing sole carbon source from readily biodegradable acetate to toxic phenol.

    Science.gov (United States)

    Wu, Changyong; Zhou, Yuexi; Song, Jiamei

    2016-01-01

    A sequencing batch reactor was used to investigate the effect of carbon sources on the metabolism of activated sludge. Acetate and phenol, with the chemical oxygen demand (COD) of 330-350 mg L(-1), was used as the carbon source in Periods I and II, respectively. Acetate decreased in the initial 120 min with the intracellular storage materials (XSTO), extracellular polymeric substances (EPS), and the soluble microbial products (SMP) accumulating to 131.0 mg L(-1), 347.5 mg L(-1), and 35.5 mg L(-1), respectively. Then, XSTO and EPS decreased to 124.5 mg L(-1) and 340.0 mg L(-1), respectively, in the following 120 min. When acetate was replaced by phenol, it could not be used at the beginning due to its toxicity. The XSTO decreased from 142 mg L(-1) to 54.6 mg L(-1) during the aeration period. The EPS had a significant increase, with the highest value of 618.1 mg L(-1), which then decreased to 245.6 mg L(-1) at 240 min. The phenol was gradually degraded with the acclimation and it can be fully degraded 18 d later. Meanwhile, the usage ratio of the internal carbon source decreased. The effluent SMP in Period II was 1.7 times that in Period I. PMID:27191552

  18. Comparative genome analysis of central nitrogen metabolism and its control by GlnR in the class Bacilli

    Directory of Open Access Journals (Sweden)

    Kormelink Tom

    2012-05-01

    Full Text Available Abstract Background The assimilation of nitrogen in bacteria is achieved through only a few metabolic conversions between alpha-ketoglutarate, glutamate and glutamine. The enzymes that catalyze these conversions are glutamine synthetase, glutaminase, glutamate dehydrogenase and glutamine alpha-ketoglutarate aminotransferase. In low-GC Gram-positive bacteria the transcriptional control over the levels of the related enzymes is mediated by four regulators: GlnR, TnrA, GltC and CodY. We have analyzed the genomes of all species belonging to the taxonomic families Bacillaceae, Listeriaceae, Staphylococcaceae, Lactobacillaceae, Leuconostocaceae and Streptococcaceae to determine the diversity in central nitrogen metabolism and reconstructed the regulation by GlnR. Results Although we observed a substantial difference in the extent of central nitrogen metabolism in the various species, the basic GlnR regulon was remarkably constant and appeared not affected by the presence or absence of the other three main regulators. We found a conserved regulatory association of GlnR with glutamine synthetase (glnRA operon, and the transport of ammonium (amtB-glnK and glutamine/glutamate (i.e. via glnQHMP, glnPHQ, gltT, alsT. In addition less-conserved associations were found with, for instance, glutamate dehydrogenase in Streptococcaceae, purine catabolism and the reduction of nitrite in Bacillaceae, and aspartate/asparagine deamination in Lactobacillaceae. Conclusions Our analyses imply GlnR-mediated regulation in constraining the import of ammonia/amino-containing compounds and the production of intracellular ammonia under conditions of high nitrogen availability. Such a role fits with the intrinsic need for tight control of ammonia levels to limit futile cycling.

  19. Metabolic syndrome in the rural population of Wardha, Central India: An exploratory factor analysis

    Directory of Open Access Journals (Sweden)

    Pradeep R Deshmukh

    2013-01-01

    Full Text Available Background and Objectives: Metabolic syndrome - a plausible precondition for type II diabetes and cardiovascular diseases is also on rise. To understand the mechanistic complexity of metabolic syndrome it is imperative to study the specific contribution of the determinants of metabolic syndrome. Such study can help to identify the most significant factor which may be of use in early detection as well as prevention efforts. Such information is scarcely available from India and especially from rural India. Hence, the present study was undertaken to explore for such factor which might be considered crucial for development of such pathogenesis particularly in rural population of Wardha. Methods: A cross-sectional study comprising of 300 subjects was carried out in rural area of Primary Health Center, attached to medical college with approximate 31,000 populations. The anthropometric parameters such as height, weight, waist circumference were measured. Overnight fasting samples were collected for lipid profile (total cholesterol, triglyceride, high density lipoproteins, low density lipoproteins, very low density lipoproteins and fasting blood glucose levels. The National Cholesterol Education Programme Adult Treatment Panel, ATP-III guidelines were used to categorize the study subjects. As many of the variables are highly intercorrelated, exploratory factor analysis was carried out to reduce the data to a smaller number of independent factors that accounts for the most of the variances in the data. Principal component analysis was used as a method of extraction. Results: For both sexes, three factors were extracted accounting for about 71% variance in the measured variables. An adiposity factor which accounted for highest explained variance (28%, was the initial factor extracted. It was loaded positively by waist circumference, triglyceride, and very low density lipoprotein and negatively loaded by high density lipoprotein. Second factor extracted

  20. International Workshop on Carbon Cycling and Coral Reef Metabolism; Sangosho no tanso junkan ni kansuru kokusai workshop hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-10-16

    The paper described the International Workshop on Carbon Cycling and Coral Reef Metabolism which was held at Miyako-jima, Okinawa Pref. on October 17-24, 1995. In the workshop, researchers got together which are involved in marine chemistry, marine biology, coral ecology, and environmental science, and discussed the carbon cycling and metabolism of coral reef. Discussions were made on what the coral reef ecosystem is, and what the definition of a sink or a source for CO2 is. Also discussed were scales of how much time and space should be considered to make these issues clear. Further, it was proposed that it was necessary to investigate carbon balance of both the whole system and the components of the system and to keep track of mass transfer among neighboring components of the system. Seventeen presentations were given. The workshop obtained a definite consensus on carbon balance of the coral reef system. 123 refs., 39 figs., 9 tabs.

  1. Carbon balance indicates a time limit for cultivation of organic soils in central Switzerland

    Science.gov (United States)

    Paul, Sonja; Ammann, Christof; Alewell, Christine; Leifeld, Jens

    2016-04-01

    Peatlands serve as important carbon sinks. Globally, more than 30% of the soil organic carbon is stored in organic soils, although they cover only 3% of the land surface. The agricultural use of organic soils usually requires drainage thereby transforming these soils from a net carbon sink into a net source. Currently, about 2 to 3 Gt CO2 are emitted world-wide from degrading organic soils (Joosten 2011; Parish et al. 2008) which is ca. 5% of the total anthropogenic emissions. Besides these CO2 emissions, the resulting subsidence of drained peat soils during agricultural use requires that drainage system are periodically renewed and finally to use pumping systems after progressive subsidence. In Switzerland, the Seeland region is characterised by fens which are intensively used for agriculture since 1900. The organic layer is degrading and subsequently getting shallower and the underlying mineral soil, as lake marl or loam, is approaching the surface. The questions arises for how long and under which land use practises and costs these soils can be cultivated in the near future. The study site was under crop rotation until 2009 when it was converted to extensively used grassland with the water regime still being regulated. The soil is characterised by a degraded organic horizon of 40 to 70 cm. Since December 2014 we are measuring the carbon exchange of this grassland using the Eddy-Covariance method. For 2015, the carbon balance indicates that the degraded fen is a strong carbon source, with approximately 500 g C m‑2 a‑1. The carbon balance is dominated by CO2 emissions and harvest. Methane emissions are negligible. With the gained emission factors different future scenarios are evaluated for the current cultivation practise of organic soils in central Switzerland. Joosten, H., 2011: Neues Geld aus alten Mooren: Über die Erzeugung von Kohlenstoffzertifikaten aus Moorwiedervernässungen. Telma Beiheft 4, 183-202. Parish, F., A. Sirin, D. Charman, H. Joosten, T

  2. Carbon balance indicates a time limit for cultivation of organic soils in central Switzerland

    Science.gov (United States)

    Paul, Sonja; Ammann, Christof; Alewell, Christine; Leifeld, Jens

    2016-04-01

    Peatlands serve as important carbon sinks. Globally, more than 30% of the soil organic carbon is stored in organic soils, although they cover only 3% of the land surface. The agricultural use of organic soils usually requires drainage thereby transforming these soils from a net carbon sink into a net source. Currently, about 2 to 3 Gt CO2 are emitted world-wide from degrading organic soils (Joosten 2011; Parish et al. 2008) which is ca. 5% of the total anthropogenic emissions. Besides these CO2 emissions, the resulting subsidence of drained peat soils during agricultural use requires that drainage system are periodically renewed and finally to use pumping systems after progressive subsidence. In Switzerland, the Seeland region is characterised by fens which are intensively used for agriculture since 1900. The organic layer is degrading and subsequently getting shallower and the underlying mineral soil, as lake marl or loam, is approaching the surface. The questions arises for how long and under which land use practises and costs these soils can be cultivated in the near future. The study site was under crop rotation until 2009 when it was converted to extensively used grassland with the water regime still being regulated. The soil is characterised by a degraded organic horizon of 40 to 70 cm. Since December 2014 we are measuring the carbon exchange of this grassland using the Eddy-Covariance method. For 2015, the carbon balance indicates that the degraded fen is a strong carbon source, with approximately 500 g C m-2 a-1. The carbon balance is dominated by CO2 emissions and harvest. Methane emissions are negligible. With the gained emission factors different future scenarios are evaluated for the current cultivation practise of organic soils in central Switzerland. Joosten, H., 2011: Neues Geld aus alten Mooren: Über die Erzeugung von Kohlenstoffzertifikaten aus Moorwiedervernässungen. Telma Beiheft 4, 183-202. Parish, F., A. Sirin, D. Charman, H. Joosten, T

  3. Climate Change in Central and West Asia. Routes to a More Secure, Low-Carbon Future

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-11-15

    ADB's Central and West Asian countries are Afghanistan, Armenia, Azerbaijan, Georgia, Kazakhstan, the Kyrgyz Republic, Pakistan, Tajikistan, Turkmenistan, and Uzbekistan. Geoclimatic and environmental factors make this region highly vulnerable to the risks and hazards of climate change. For example, accelerated glacial melt has serious implications for agriculture, water supply, and energy generation - problems exacerbated by overexploitation of natural resources. Countries may find it difficult to shift to low-carbon growth, since many have abundant fossil fuel and tend to use energy inefficiently. ADB is responding to these climate hazards and low-carbon pathways with a comprehensive strategy that strengthens policies, governance, and capacity support; expands the use of clean and renewable energy; encourages sustainable transport and urban development; promotes development that will be more resilient to climate change, especially in water-dependent sectors; and manages land use and forests for carbon sequestration. ADB's support is helping its developing member countries face the challenges of climate change and, with partners, is providing innovative solutions, while continuing to work to reduce poverty.

  4. ¹³C metabolic flux analysis identifies an unusual route for pyruvate dissimilation in mycobacteria which requires isocitrate lyase and carbon dioxide fixation.

    Directory of Open Access Journals (Sweden)

    Dany J V Beste

    2011-07-01

    Full Text Available Mycobacterium tuberculosis requires the enzyme isocitrate lyase (ICL for growth and virulence in vivo. The demonstration that M. tuberculosis also requires ICL for survival during nutrient starvation and has a role during steady state growth in a glycerol limited chemostat indicates a function for this enzyme which extends beyond fat metabolism. As isocitrate lyase is a potential drug target elucidating the role of this enzyme is of importance; however, the role of isocitrate lyase has never been investigated at the level of in vivo fluxes. Here we show that deletion of one of the two icl genes impairs the replication of Mycobacterium bovis BCG at slow growth rate in a carbon limited chemostat. In order to further understand the role of isocitrate lyase in the central metabolism of mycobacteria the effect of growth rate on the in vivo fluxes was studied for the first time using ¹³C-metabolic flux analysis (MFA. Tracer experiments were performed with steady state chemostat cultures of BCG or M. tuberculosis supplied with ¹³C labeled glycerol or sodium bicarbonate. Through measurements of the ¹³C isotopomer labeling patterns in protein-derived amino acids and enzymatic activity assays we have identified the activity of a novel pathway for pyruvate dissimilation. We named this the GAS pathway because it utilizes the Glyoxylate shunt and Anapleurotic reactions for oxidation of pyruvate, and Succinyl CoA synthetase for the generation of succinyl CoA combined with a very low flux through the succinate--oxaloacetate segment of the tricarboxylic acid cycle. We confirm that M. tuberculosis can fix carbon from CO₂ into biomass. As the human host is abundant in CO₂ this finding requires further investigation in vivo as CO₂ fixation may provide a point of vulnerability that could be targeted with novel drugs. This study also provides a platform for further studies into the metabolism of M. tuberculosis using ¹³C-MFA.

  5. Stable and radioactive carbon in forest soils of Chhattisgarh, Central India: Implications for tropical soil carbon dynamics and stable carbon isotope evolution

    Science.gov (United States)

    Laskar, A. H.; Yadava, M. G.; Ramesh, R.

    2016-06-01

    Soils from two sites viz. Kotumsar and Tirathgarh, located ∼5 km apart in a tropical reserve forest (18°52‧N, 81°56‧E) in central India, have been explored for soil organic carbon (SOC) content, its mean residence time (MRT) and the evolution of stable carbon isotopic composition (δ13C). SOC stocks in the upper 30 cm of soil layers are ∼5.3 kg/m2 and ∼3.0 kg/m2; in the upper 110 m are ∼10.7 kg/m2 and ∼7.8 kg/m2 at Kotumsar and Tirathgarh, respectively. SOC decreases with increasing depth. Bomb carbon signature is observed in the upper ∼10 cm. Organic matters in the top soil layers (0-10 cm) have MRTs of the order of a century which increases gradually with depths, reaching 3500-5000 yrs at ∼100 cm. δ13C values of SOC increase with depth, the carbon isotopic fractionation is obtained to be -1.2‰ and -3‰ for soils at Kotumsar and Tirathgarh, respectively, confirmed using Rayleigh isotopic fractionation model. The evolution of δ13C in soils was also studied using a modified Rayleigh fractionation model incorporating a continuous input into the reservoir: the depth profiles of δ13C for SOC show that the input organic matter from surface into the deeper soil layers is either insignificant or highly labile and decomposes quite fast in the top layers, thus making little contribution to the residual biomasses of the deeper layers. This is an attempt to understand the distillation processes that take place in SOC, assess the extent of decomposition by microbes and effect of percolation of fresh organic matter into dipper soil layers which are important for stable isotope based paleoclimate and paleovegetation reconstruction and understanding the dynamics of organic carbon in soils.

  6. Comparative genomic reconstruction of transcriptional networks controlling central metabolism in the Shewanella genus

    Directory of Open Access Journals (Sweden)

    Kovaleva Galina

    2011-06-01

    Full Text Available Abstract Background Genome-scale prediction of gene regulation and reconstruction of transcriptional regulatory networks in bacteria is one of the critical tasks of modern genomics. The Shewanella genus is comprised of metabolically versatile gamma-proteobacteria, whose lifestyles and natural environments are substantially different from Escherichia coli and other model bacterial species. The comparative genomics approaches and computational identification of regulatory sites are useful for the in silico reconstruction of transcriptional regulatory networks in bacteria. Results To explore conservation and variations in the Shewanella transcriptional networks we analyzed the repertoire of transcription factors and performed genomics-based reconstruction and comparative analysis of regulons in 16 Shewanella genomes. The inferred regulatory network includes 82 transcription factors and their DNA binding sites, 8 riboswitches and 6 translational attenuators. Forty five regulons were newly inferred from the genome context analysis, whereas others were propagated from previously characterized regulons in the Enterobacteria and Pseudomonas spp.. Multiple variations in regulatory strategies between the Shewanella spp. and E. coli include regulon contraction and expansion (as in the case of PdhR, HexR, FadR, numerous cases of recruiting non-orthologous regulators to control equivalent pathways (e.g. PsrA for fatty acid degradation and, conversely, orthologous regulators to control distinct pathways (e.g. TyrR, ArgR, Crp. Conclusions We tentatively defined the first reference collection of ~100 transcriptional regulons in 16 Shewanella genomes. The resulting regulatory network contains ~600 regulated genes per genome that are mostly involved in metabolism of carbohydrates, amino acids, fatty acids, vitamins, metals, and stress responses. Several reconstructed regulons including NagR for N-acetylglucosamine catabolism were experimentally validated in S

  7. The flexible feedstock concept in Industrial Biotechnology: Metabolic engineering of Escherichia coli, Corynebacterium glutamicum, Pseudomonas, Bacillus and yeast strains for access to alternative carbon sources.

    Science.gov (United States)

    Wendisch, Volker F; Brito, Luciana Fernandes; Gil Lopez, Marina; Hennig, Guido; Pfeifenschneider, Johannes; Sgobba, Elvira; Veldmann, Kareen H

    2016-09-20

    Most biotechnological processes are based on glucose that is either present in molasses or generated from starch by enzymatic hydrolysis. At the very high, million-ton scale production volumes, for instance for fermentative production of the biofuel ethanol or of commodity chemicals such as organic acids and amino acids, competing uses of carbon sources e.g. in human and animal nutrition have to be taken into account. Thus, the biotechnological production hosts E. coli, C. glutamicum, pseudomonads, bacilli and Baker's yeast used in these large scale processes have been engineered for efficient utilization of alternative carbon sources. This flexible feedstock concept is central to the use of non-glucose second and third generation feedstocks in the emerging bioeconomy. The metabolic engineering efforts to broaden the substrate scope of E. coli, C. glutamicum, pseudomonads, B. subtilis and yeasts to include non-native carbon sources will be reviewed. Strategies to enable simultaneous consumption of mixtures of native and non-native carbon sources present in biomass hydrolysates will be summarized and a perspective on how to further increase feedstock flexibility for the realization of biorefinery processes will be given. PMID:27491712

  8. Essential roles of four-carbon backbone chemicals in the control of metabolism

    Institute of Scientific and Technical Information of China (English)

    Sabrina; Chriett; Luciano; Pirola

    2015-01-01

    The increasing incidence of obesity worldwide and its related cardiometabolic complications is an urgent public health problem. While weight gain results from a negative balance between the energy expenditure and calorie intake, recent research has demonstrated that several small organic molecules containing a four-carbon backbone can modulate this balance by favoring energy expenditure, and alleviating endoplasmic reticulum stress and oxidative stress. Such small molecules include the bacterially produced short chain fatty acid butyric acid, its chemically produced derivative 4-phenylbutyric acid, the main ketone body D-β-hydroxybutyrate- synthesized by the liver- and the recently discovered myokine β-aminoisobutyric acid. Conversely, another butyraterelated molecule, α-hydroxybutyrate, has been found to be an early predictor of insulin resistance and glucose intolerance. In this minireview, we summarize recent advances in the understanding of the mechanism of action of these molecules, and discuss their use as therapeutics to improve metabolic homeostasis or their detection as early biomarkers of incipient insulin resistance.

  9. Carbon and nitrogen metabolism in arbuscular mycorrhizal maize plants under low-temperature stress

    DEFF Research Database (Denmark)

    Zhu, Xian-Can; Song, Feng-Bin; Liu, Fulai;

    2015-01-01

    Effects of the arbuscular mycorrhizal (AM) fungus Glomus tortuosum on carbon (C) and nitrogen (N) metabolism of Zea mays L. grown under low-temperature stress was investigated. Maize plants inoculated or not inoculated with AM fungus were grown in a growth chamber at 258C for 4 weeks...... and subsequently subjected to two temperature treatments (158C, low temperature; 258C, ambient control) for 2 weeks. Low-temperature stress significantly decreasedAMcolonisation, plant height and biomass. TotalNcontent and activities of glutamate oxaloacetate transaminase and glutamate pyruvate transaminase of AM...... plants were higher than those of non-AM plants. AM plants had a higher net photosynthetic rate (Pn) than non-AM plants, although low temperature inhibited the Pn. Compared with non-AM plants, AM plants exhibited higher leaf soluble sugars, reducing sugars, root sucrose and fructose contents, and sucrose...

  10. Static magnetic field treatment of seeds improves carbon and nitrogen metabolism under salinity stress in soybean.

    Science.gov (United States)

    Baghel, Lokesh; Kataria, Sunita; Guruprasad, Kadur Narayan

    2016-10-01

    The effectiveness of magnetopriming was assessed for alleviation of salt-induced adverse effects on soybean growth. Soybean seeds were pre-treated with static magnetic field (SMF) of 200 mT for 1 h to evaluate the effect of magnetopriming on growth, carbon and nitrogen metabolism, and yield of soybean plants under different salinity levels (0, 25, and 50 mM NaCl). The adverse effect of NaCl-induced salt stress was found on growth, yield, and various physiological attributes of soybeans. Results indicate that SMF pre-treatment significantly increased plant growth attributes, number of root nodules, nodules, fresh weight, biomass accumulation, and photosynthetic performance under both non-saline and saline conditions as compared to untreated seeds. Polyphasic chlorophyll a fluorescence (OJIP) transients from magnetically treated plants gave a higher fluorescence yield at J-I-P phase. Nitrate reductase activity, PIABS , photosynthetic pigments, and net rate of photosynthesis were also higher in plants that emerged from SMF pre-treated seeds as compared to untreated seeds. Leghemoglobin content and hemechrome content in root nodules were also increased by SMF pre-treatment. Thus pre-sowing exposure of seeds to SMF enhanced carbon and nitrogen metabolism and improved the yield of soybeans in terms of number of pods, number of seeds, and seed weight under saline as well as non-saline conditions. Consequently, SMF pre-treatment effectively mitigated adverse effects of NaCl on soybeans. It indicates that magnetopriming of dry soybean seeds can be effectively used as a pre-sowing treatment for alleviating salinity stress. Bioelectromagnetics. 37:455-470, 2016. © 2016 Wiley Periodicals, Inc. PMID:27336791

  11. Pathway confirmation and flux analysis of central metabolic pathways in Desulfovibrio vulgaris Hildenborough using Gas Chromatography-Mass Spectrometry and Fourier Transform-Ion Cyclotron Resonance Mass Spectrometry

    International Nuclear Information System (INIS)

    Flux distribution in central metabolic pathways of Desulfovibrio vulgaris Hildenborough was examined using 13C tracer experiments. Consistent with the current genome annotation and independent evidence from enzyme activity assays, the isotopomer results from both GC-MS and Fourier Transform-Ion Cyclotron Resonance mass spectrometry (FT-ICR MS) indicate the lack of oxidatively functional TCA cycle and an incomplete pentose phosphate pathway. Results from this study suggest that fluxes through both pathways are limited to biosynthesis. The data also indicate that >80 percent of the lactate was converted to acetate and the reactions involved are the primary route of energy production (NAD(P)H and ATP production). Independent of the TCA cycle, direct cleavage of acetyl-CoA to CO and 5,10-methyl-THF also leads to production of NADH and ATP. Although the genome annotation implicates a ferredoxin-dependent oxoglutarate synthase, isotopic evidence does not support flux through this reaction in either the oxidative or reductive mode; therefore, the TCA cycle is incomplete. FT-ICR MS was used to locate the labeled carbon distribution in aspartate and glutamate and confirmed the presence of an atypical enzyme for citrate formation suggested in previous reports (the citrate synthesized by this enzyme is the isotopic antipode of the citrate synthesized by the (S)-citrate synthase). These findings enable a better understanding of the relation between genome annotation and actual metabolic pathways in D. vulgaris, and also demonstrate FT-ICR MS as a powerful tool for isotopomer analysis, overcoming problems in both GC-MS and NMR spectroscopy

  12. Computational and experimental analysis of redundancy in the central metabolism of Geobacter sulfurreducens.

    Directory of Open Access Journals (Sweden)

    Daniel Segura

    2008-02-01

    Full Text Available Previous model-based analysis of the metabolic network of Geobacter sulfurreducens suggested the existence of several redundant pathways. Here, we identified eight sets of redundant pathways that included redundancy for the assimilation of acetate, and for the conversion of pyruvate into acetyl-CoA. These equivalent pathways and two other sub-optimal pathways were studied using 5 single-gene deletion mutants in those pathways for the evaluation of the predictive capacity of the model. The growth phenotypes of these mutants were studied under 12 different conditions of electron donor and acceptor availability. The comparison of the model predictions with the resulting experimental phenotypes indicated that pyruvate ferredoxin oxidoreductase is the only activity able to convert pyruvate into acetyl-CoA. However, the results and the modeling showed that the two acetate activation pathways present are not only active, but needed due to the additional role of the acetyl-CoA transferase in the TCA cycle, probably reflecting the adaptation of these bacteria to acetate utilization. In other cases, the data reconciliation suggested additional capacity constraints that were confirmed with biochemical assays. The results demonstrate the need to experimentally verify the activity of key enzymes when developing in silico models of microbial physiology based on sequence-based reconstruction of metabolic networks.

  13. Central Asian supra-glacier snow melt enhanced by anthropogenic black carbon

    Science.gov (United States)

    Schmale, Julia; Flanner, Mark; Kang, Shichang; Sprenger, Michael; Farinotti, Daniel; Zhang, Qianggong; Guo, Junming; Li, Yang; Lawrence, Mark; Schwikowski, Margit

    2016-04-01

    In Central Asia, more than 60 % of the population depends on water stored in glaciers and mountain snow. Densely populated areas near lower-lying mountain ranges are particularly vulnerable and a recent study showed that the region might lose 50 % of its glacier mass by 2050. While temperature, precipitation and dynamic processes are key drivers of glacial change, deposition of light absorbing impurities such as mineral dust and black carbon can lead to accelerated melting through surface albedo reduction. Here, we discuss the origin of deposited mineral dust and black carbon and their impacts on albedo change and snow melt. 218 snow samples were taken on 4 glaciers, Abramov (Pamir), Suek, Glacier No. 354 and Golubin (Tien Shan), representing deposition between summer 2012 and 2014. They were analyzed for elemental carbon, mineral dust and iron among other parameters. We find the elemental carbon concentration to be at the higher end of the range reported for neighboring mountain ranges between 70 and 502 ng g-1 (interquartile range). To investigate the origin of the snow impurities, we used a Lagrangian particle dispersion model, LAGRANTO. Back trajectory ensembles of 40 members with varied starting points to capture the meteorological spread were released every 6 hours for the covered period at all sites. "Footprints" were calculated and combined with emission inventories to estimate the relative contribution of anthropogenic and natural BC to deposited aerosol on the glaciers. We find that more than 94 % of BC is of anthropogenic origin and the major source region is Central Asia followed by the Middle East. Further exploring the implications of mineral dust and BC deposition, we calculate the snow albedo reduction with the Snow-Ice-Aerosol-Radiative model (SNICAR). Even though mineral dust concentrations were up to a factor of 50 higher than BC concentrations, BC dominates the albedo reduction. Using these results we calculate the snow melt induced by

  14. [Carbon emissions and low-carbon regulation countermeasures of land use change in the city and town concentrated area of central Liaoning Province, China].

    Science.gov (United States)

    Xi, Feng-ming; Liang, Wen-juan; Niu, Ming-fen; Wang, Jiao-yue

    2016-02-01

    Carbon emissions due to land use change have an important impact on global climate change. Adjustment of regional land use patterns has a great scientific significance to adaptation to a changing climate. Based on carbon emission/absorption parameters suitable for Liaoning Province, this paper estimated the carbon emission of land use change in the city and town concentrated area of central Liaoning Province. The results showed that the carbon emission and absorption were separately 308.51 Tg C and 11.64 Tg C from 1997 to 2010. It meant 3.8% of carbon emission. was offset by carbon absorption. Among the 296.87 Tg C net carbon emission of land use change, carbon emission of remaining land use type was 182.24 Tg C, accounting for 61.4% of the net carbon emission, while the carbon emission of land use transformation was 114.63 Tg C, occupying the rest 38.6% of net carbon emission. Through quantifying the mapping relationship between land use change and carbon emission, it was shown that during 1997-2004 the contributions of remaining construction land (40.9%) and cropland transform ation to construction land (40.6%) to carbon emission were larger, but the greater contributions to carbon absorption came from cropland transformation to forest land (38.6%) and remaining forest land (37.5%). During 2004-2010, the land use types for carbon emission and absorption were the same to the period of 1997-2004, but the contribution of remaining construction land to carbon emission increased to 80.6%, and the contribution of remaining forest land to carbon absorption increased to 71.7%. Based on the carbon emission intensity in different land use types, we put forward the low-carbon regulation countermeasures of land use in two aspects. In carbon emission reduction, we should strict control land transformation to construction land, increase the energy efficiency of construction land, and avoid excessive development of forest land and water. In carbon sink increase, we should

  15. [Carbon emissions and low-carbon regulation countermeasures of land use change in the city and town concentrated area of central Liaoning Province, China].

    Science.gov (United States)

    Xi, Feng-ming; Liang, Wen-juan; Niu, Ming-fen; Wang, Jiao-yue

    2016-02-01

    Carbon emissions due to land use change have an important impact on global climate change. Adjustment of regional land use patterns has a great scientific significance to adaptation to a changing climate. Based on carbon emission/absorption parameters suitable for Liaoning Province, this paper estimated the carbon emission of land use change in the city and town concentrated area of central Liaoning Province. The results showed that the carbon emission and absorption were separately 308.51 Tg C and 11.64 Tg C from 1997 to 2010. It meant 3.8% of carbon emission. was offset by carbon absorption. Among the 296.87 Tg C net carbon emission of land use change, carbon emission of remaining land use type was 182.24 Tg C, accounting for 61.4% of the net carbon emission, while the carbon emission of land use transformation was 114.63 Tg C, occupying the rest 38.6% of net carbon emission. Through quantifying the mapping relationship between land use change and carbon emission, it was shown that during 1997-2004 the contributions of remaining construction land (40.9%) and cropland transform ation to construction land (40.6%) to carbon emission were larger, but the greater contributions to carbon absorption came from cropland transformation to forest land (38.6%) and remaining forest land (37.5%). During 2004-2010, the land use types for carbon emission and absorption were the same to the period of 1997-2004, but the contribution of remaining construction land to carbon emission increased to 80.6%, and the contribution of remaining forest land to carbon absorption increased to 71.7%. Based on the carbon emission intensity in different land use types, we put forward the low-carbon regulation countermeasures of land use in two aspects. In carbon emission reduction, we should strict control land transformation to construction land, increase the energy efficiency of construction land, and avoid excessive development of forest land and water. In carbon sink increase, we should

  16. Effects of oxidative stress on fatty acid- and one-carbon-metabolism in psychiatric and cardiovascular disease comorbidity

    NARCIS (Netherlands)

    Assies, J.; Mocking, R.J.; Lok, A.; Ruhe, H.G.; Pouwer, F.; Schene, A.H.

    2014-01-01

    OBJECTIVE: Cardiovascular disease (CVD) is the leading cause of death in severe psychiatric disorders (depression, schizophrenia). Here, we provide evidence of how the effects of oxidative stress on fatty acid (FA) and one-carbon (1-C) cycle metabolism, which may initially represent adaptive respons

  17. Effects of oxidative stress on fatty acid- and one-carbon-metabolism in psychiatric and cardiovascular disease comorbidity

    NARCIS (Netherlands)

    Assies, J.; Mocking, R. J. T.; Lok, A.; Ruhe, H. G.; Pouwer, F.; Schene, A. H.

    2014-01-01

    Objective: Cardiovascular disease (CVD) is the leading cause of death in severe psychiatric disorders (depression, schizophrenia). Here, we provide evidence of how the effects of oxidative stress on fatty acid (FA) and one-carbon (1-C) cycle metabolism, which may initially represent adaptive respons

  18. Formation mechanism of carbonate cemented zones adjacent to the top overpressured surface in the central Junggar Basin,NW China

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Carbonate cemented zones are normally adjacent to the top overpressured surface in the central Junggar Basin,NW China.Stable carbon and oxygen isotopic compositions and petrological investigations of carbonate cements in the carbonate cemented zones indicate that:(1) carbonate cements are composed dominantly of ferrocalcite,ferroan dolomite,and ankerite;(2) carbonate cements are formed under a high temperature circumstance in the subsurface,and organic fluid migration has an important effect on the formation of them;and(3) carbon and oxygen ions in the carbonate cements migrate from the underlying overpressured system.This suggests that the occurrence of carbonate cemented zones in this region results from multiple phases of organic fluid expulsion out of the overpressure compartment through geological time.This study provides a plausible mechanism of the formation of carbonate cemented zones adjacent to the top overpressured surface in the clastic sedimentary basins,and has an important implication for understanding the internal correlation between the formation of carbonate cemented zones adjacent to top overpressured surface and geofluids expulsion out of overpressured system.

  19. Metabolic flux analysis of Escherichia coli creB and arcA mutants reveals shared control of carbon catabolism under microaerobic growth conditions.

    Science.gov (United States)

    Nikel, Pablo I; Zhu, Jiangfeng; San, Ka-Yiu; Méndez, Beatriz S; Bennett, George N

    2009-09-01

    Escherichia coli has several elaborate sensing mechanisms for response to availability of oxygen and other electron acceptors, as well as the carbon source in the surrounding environment. Among them, the CreBC and ArcAB two-component signal transduction systems are responsible for regulation of carbon source utilization and redox control in response to oxygen availability, respectively. We assessed the role of CreBC and ArcAB in regulating the central carbon metabolism of E. coli under microaerobic conditions by means of (13)C-labeling experiments in chemostat cultures of a wild-type strain, DeltacreB and DeltaarcA single mutants, and a DeltacreB DeltaarcA double mutant. Continuous cultures were conducted at D = 0.1 h(-1) under carbon-limited conditions with restricted oxygen supply. Although all experimental strains metabolized glucose mainly through the Embden-Meyerhof-Parnas pathway, mutant strains had significantly lower fluxes in both the oxidative and the nonoxidative pentose phosphate pathways. Significant differences were also found at the pyruvate branching point. Both pyruvate-formate lyase and the pyruvate dehydrogenase complex contributed to acetyl-coenzyme A synthesis from pyruvate, and their activity seemed to be modulated by both ArcAB and CreBC. Strains carrying the creB deletion showed a higher biomass yield on glucose compared to the wild-type strain and its DeltaarcA derivative, which also correlated with higher fluxes from building blocks to biomass. Glyoxylate shunt and lactate dehydrogenase were active mainly in the DeltaarcA strain. Finally, it was observed that the tricarboxylic acid cycle reactions operated in a rather cyclic fashion under our experimental conditions, with reduced activity in the mutant strains.

  20. The Role of CYP2E1 in Alcohol Metabolism and Sensitivity in the Central Nervous System

    Science.gov (United States)

    Heit, Claire; Dong, Hongbin; Chen, Ying; Thompson, David C.; Deitrich, Richard A.; Vasiliou, Vasilis

    2015-01-01

    Ethanol consumption has effects on the central nervous system (CNS), manifesting as motor incoordination, sleep induction (hypnosis), anxiety, amnesia, and the reinforcement or aversion of alcohol consumption. Acetaldehyde (the direct metabolite of ethanol oxidation) contributes to many aspects of the behavioral effects of ethanol. Given acetaldehyde cannot pass through the blood brain barrier, its concentration in the CNS is primarily determined by local production from ethanol. Catalase and cytochrome P450 2E1(CYP2E1) represent the major enzymes in the CNS that catalyze ethanol oxidation. CYP2E1 is expressed abundantly within the microsomes of certain brain cells and is localized to particular brain regions. This chapter focuses on the discussion of CYP2E1 in ethanol metabolism in the CNS, covering topics including how it is regulated, where it is expressed and how it influences sensitivity to ethanol in the brain. PMID:23400924

  1. The regulatory role of Streptomyces coelicolor TamR in central metabolism.

    Science.gov (United States)

    Huang, Hao; Sivapragasam, Smitha; Grove, Anne

    2015-03-01

    Trans-aconitate methyltransferase regulator (TamR) is a member of the ligand-responsive multiple antibiotic resistance regulator (MarR) family of transcription factors. In Streptomyces coelicolor, TamR regulates transcription of tamR (encoding TamR), tam (encoding trans-aconitate methyltransferase) and sacA (encoding aconitase); up-regulation of these genes promotes metabolic flux through the citric acid cycle. DNA binding by TamR is attenuated and transcriptional derepression is achieved on binding of ligands such as citrate and trans-aconitate to TamR. In the present study, we show that three additional genes are regulated by S. coelicolor TamR. Genes encoding malate synthase (aceB1; SCO6243), malate dehydrogenase (mdh; SCO4827) and isocitrate dehydrogenase (idh; SCO7000) are up-regulated in vivo when citrate and trans-aconitate accumulate, and TamR binds the corresponding gene promoters in vitro, a DNA binding that is attenuated by cognate ligands. Mutations to the TamR binding site attenuate DNA binding in vitro and result in constitutive promoter activity in vivo. The predicted TamR binding sites are highly conserved in the promoters of these genes in Streptomyces species that encode divergent tam-tamR gene pairs, suggesting evolutionary conservation. Like aconitase and trans-aconitate methyltransferase, malate dehydrogenase, isocitrate dehydrogenase and malate synthase are closely related to the citric acid cycle, either catalysing individual reaction steps or, in the case of malate synthase, participating in the glyoxylate cycle to produce malate that enters the citric acid cycle to replenish the intermediate pool. Taken together, our data suggest that TamR plays an important and conserved role in promoting metabolic flux through the citric acid cycle.

  2. Deforestation projections for carbon-rich peat swamp forests of Central Kalimantan, Indonesia.

    Science.gov (United States)

    Fuller, Douglas O; Hardiono, Martin; Meijaard, Erik

    2011-09-01

    We evaluated three spatially explicit land use and cover change (LUCC) models to project deforestation from 2005-2020 in the carbon-rich peat swamp forests (PSF) of Central Kalimantan, Indonesia. Such models are increasingly used to evaluate the impact of deforestation on carbon fluxes between the biosphere and the atmosphere. We considered both business-as-usual (BAU) and a forest protection scenario to evaluate each model's accuracy, sensitivity, and total projected deforestation and landscape-level fragmentation patterns. The three models, Dinamica EGO (DE), GEOMOD and the Land Change Modeler (LCM), projected similar total deforestation amounts by 2020 with a mean of 1.01 million ha (Mha) and standard deviation of 0.17 Mha. The inclusion of a 0.54 Mha strict protected area in the LCM simulations reduced projected loss to 0.77 Mha over 15 years. Calibrated parameterizations of the models using nearly identical input drivers produced very different landscape properties, as measured by the number of forest patches, mean patch area, contagion, and Euclidean nearest neighbor determined using Fragstats software. The average BAU outputs of the models suggests that Central Kalimantan may lose slightly less than half (45.1%) of its 2005 PSF by 2020 if measures are not taken to reduce deforestation there. The relatively small reduction of 0.24 Mha in deforestation found in the 0.54 Mha protection scenario suggests that these models can identify potential leakage effects in which deforestation is forced to occur elsewhere in response to a policy intervention.

  3. Chemical constraints governing the origin of metabolism: the thermodynamic landscape of carbon group transformations under mild aqueous conditions

    Science.gov (United States)

    Weber, Arthur L.

    2002-01-01

    The thermodynamics of organic chemistry under mild aqueous conditions was examined in order to begin to understand its influence on the structure and operation of metabolism and its antecedents. Free energies (deltaG) were estimated for four types of reactions of biochemical importance carbon-carbon bond cleavage and synthesis, hydrogen transfer between carbon groups, dehydration of alcohol groups, and aldo-keto isomerization. The energies were calculated for mainly aliphatic groups composed of carbon, hydrogen, and oxygen. The energy values showed (1) that generally when carbon-carbon bond cleavage involves groups from different functional group classes (i.e., carboxylic acids, carbonyl groups, alcohols, and hydrocarbons), the transfer of the shared electron-pair to the more reduced carbon group is energetically favored over transfer to the more oxidized carbon group, and (2) that the energy of carbon-carbon bond transformation is primarily determined by the functional group class of the group that changes oxidation state in the reaction (i.e., the functional group class of the group that donates the shared electron-pair during cleavage, or that accepts the incipient shared electron-pair during synthesis). In contrast, the energy of hydrogen transfer between carbon groups is determined by the functional group class of both the hydrogen-donor group and the hydrogen-acceptor group. From these and other observations we concluded that the chemistry involved in the origin of metabolism (and to a lesser degree modern metabolism) was strongly constrained by (1) the limited redox-based transformation energy of organic substrates that is readily dissipated in a few energetically favorable irreversible reactions; (2) the energy dominance of a few transformation half-reactions that determines whether carbon-carbon bond transformation (cleavage or synthesis) is energetically favorable (deltaG +3.5 kcal/mol); and (3) the dependence of carbon group transformation energy on the

  4. Forest Restoration Carbon Analysis of Baseline Carbon Emissions and Removal in Tropical Rainforest at La Selva Central, Peru

    Energy Technology Data Exchange (ETDEWEB)

    Patrick Gonzalez; Benjamin Kroll; Carlos R. Vargas

    2006-01-10

    Conversion of tropical forest to agricultural land and pasture has reduced forest extent and the provision of ecosystem services, including watershed protection, biodiversity conservation, and carbon sequestration. Forest conservation and reforestation can restore those ecosystem services. We have assessed forest species patterns, quantified deforestation and reforestation rates, and projected future baseline carbon emissions and removal in Amazon tropical rainforest at La Selva Central, Peru. The research area is a 4800 km{sup 2} buffer zone around the Parque Nacional Yanachaga-Chemillen, Bosque de Proteccion San Matias-San Carlos, and the Reserva Comunal Yanesha. A planned project for the period 2006-2035 would conserve 4000 ha of forest in a proposed 7000 ha Area de Conservacion Municipale de Chontabamba and establish 5600 ha of natural regeneration and 1400 ha of native species plantations, laid out in fajas de enriquecimiento (contour plantings), to reforest 7000 ha of agricultural land. Forest inventories of seven sites covering 22.6 ha in primary forest and 17 sites covering 16.5 ha in secondary forest measured 17,073 trees of diameter {ge} 10 cm. The 24 sites host trees of 512 species, 267 genera, and 69 families. We could not identify the family of 7% of the trees or the scientific species of 21% of the trees. Species richness is 346 in primary forest and 257 in the secondary forest. In primary forest, 90% of aboveground biomass resides in old-growth species. Conversely, in secondary forest, 66% of aboveground biomass rests in successional species. The density of trees of diameter {ge} 10 cm is 366 trees ha{sup -1} in primary forest and 533 trees ha{sup -1} in secondary forest, although the average diameter is 24 {+-} 15 cm in primary forest and 17 {+-} 8 cm in secondary forest. Using Amazon forest biomass equations and wood densities for 117 species, aboveground biomass is 240 {+-} 30 t ha{sup -1} in the primary sites and 90 {+-} 10 t ha{sup -1} in the

  5. Pyruvate Oxidoreductases Involved in Glycolytic Anaerobic Metabolism of Polychaetes from the Continental Shelf off Central-South Chile

    Science.gov (United States)

    González, R. R.; Quiñones, R. A.

    2000-10-01

    The presence of low oxygen conditions in extensive areas of the continental shelf off central-south Chile has important effects on the biochemical adaptations of the organisms living in this ecosystem. Polychaetes assemblages cohabit on the shelf with an extensively distributed prokaryotic community made up of giant filamentous sulfur bacteria (mainly Thioploca sp.). The aim of this research was to characterize the pyruvate oxidoreductases enzymes involved in the biochemical adaptation of these benthic polychaetes. Nine polychaete species ( Paraprionospio pinnata, Nephtys ferruginea, Glycera americana, Haploscoloplos sp., Lumbrineris composita, Sigambra bassi, Aricidea pigmentata , Cossura chilensis, and Pectinaria chilensis) were assayed for lactic dehydrogenase (LDH), octopine dehydrogenase (OPDH), strombine dehydrogenase (STRDH) and alanopine dehydrogenase (ALPDH). Each species had a characteristic number of the pyruvate oxidoreductases assayed ranging from 4 in Paraprionospio pinnata to 1 in Pectinaria chilensis . The pyruvate saturation curves obtained for the enzymes from all species analysed, except L. composita, suggest that NADH can be oxidized at different rates depending on the amino acid used in the reaction with pyruvate. Our results indicate that organisms having more that one pyruvate oxidoreductase present a greater metabolic capacity to cope with functional and environmental hypoxia because these enzymes would better regulate the pyruvate consumption rate during the transition period. Thus, the dominance of Paraprionospio pinnata in the study area and its worldwide distribution is consistent with its higher number of pyruvate oxidoreductases with different pyruvate consumption rates involved in anaerobic metabolism. Finally, a positive allometric relationship was found between body size and the specific activity of ALPDH, STRDH, and maximum pyruvate oxidoreductase specific activity. This latter result suggests a positive scaling of the specific

  6. Association between in vivo alcohol metabolism and genetic variation in pathways that metabolize the carbon skeleton of ethanol and NADH reoxidation in the Alcohol Challenge Twin Study

    Science.gov (United States)

    Lind, Penelope A; Macgregor, Stuart; Heath, Andrew C; Madden, Pamela AF; Montgomery, Grant W; Martin, Nicholas G; Whitfield, John B

    2013-01-01

    Background Variation in alcohol metabolism affects the duration of intoxication and alcohol use. While the majority of genetic association studies investigating variation in alcohol metabolism have focused on polymorphisms in alcohol or aldehyde dehydrogenases, we have now tested for association with genes in alternative metabolic pathways that catalyze the carbon skeleton of ethanol and NADH reoxidation. Methods 950 single nucleotide polymorphisms (SNPs) spanning 14 genes (ACN9, ACSS1, ACSS2, ALDH1A1, CAT, CYP2E1, GOT1, GOT2, MDH1, MDH2, SLC25A10, SLC25A11, SLC25A12, SLC25A13) were genotyped in 352 young adults who participated in an alcohol challenge study. Traits tested were blood and breath alcohol concentration, peak alcohol concentration and rates of alcohol absorption and elimination. Allelic association was tested using quantitative univariate and multivariate methods. Results A CYP2E1 promoter SNP (rs4838767, minor allele frequency 0.008) exceeded the threshold for study-wide significance (4.01 × 10−5) for two early blood alcohol concentration (BAC), eight breath alcohol concentration (BrAC) measures and the peak BrAC. For each phenotype the minor C-allele was related to a lower alcohol concentration, most strongly for the fourth BrAC (P = 2.07 × 10−7) explaining ~8% of the phenotypic variance. We also observed suggestive patterns of association with variants in ALDH1A1 and on chromosome 17 near SLC25A11 for aspects of blood and breath alcohol metabolism. A SNP upstream of GOT1 (rs2490286) reached study-wide significance for multivariate BAC metabolism (P = 0.000040). Conclusions Overall, we did not find strong evidence that variation in genes coding for proteins that further metabolize the carbon backbone of acetaldehyde, or contribute to mechanisms for regenerating NAD from NADH, affects alcohol metabolism in our European-descent subjects. However, based on the breath alcohol data, variation in the promoter of CYP2E1 may play a role in pre

  7. Effects of wildfire on soil organic carbon export by runoff in Central Portugal

    Science.gov (United States)

    Varela, M. E.; Faria, S. R.; Campos, I.; Caria, M. M. P. F.; Ferreira, R. S. V.; Machado, A. I.; Martins, M. A. S.; Pinto, R.; Prats, S. A.; Esteves, V. I.; Keizer, J. J.

    2012-04-01

    Forest fires, a frequent and recurrent phenomenon in Mediterranean ecosystems, have several ecological and environmental impacts caused in part by short- and medium-term effects on soil physical and chemical characteristics as well as on organic matter (OM) composition, properties and dynamics and hence upon microbial populations. This negatively affects soil health and quality, and enhances the occurrence of erosive processes and the loss of a non-renewable natural resource such is the soil. Due to the large C pool present in soils, even small changes in soil OM may have a significant effect on biogeochemical cycles and on global climate. Even though some authors consider that organic C mobilized by erosion processes may be protected from mineralization, the general tendency is to consider that soil erosion exposes OM to mineralization processes and represents the main factor of C losses from the planet's surface. Whilst it is well documented that wildfires can have major impacts on hydrological and erosion processes, the associated transport of organic matter has received considerably less research attention. The FIRECNUTS project (PTDC/AGR-CFL/104559/2008) addresses this research gap by studying, among others, the export of organic carbon in a recently burnt forest area of 250 ha in north-central Portugal (Sever do Vouga). To this end, five slopes with contrasting forest types (eucalypt vs. Maritime Pine plantations) and geologies (schist vs. granite) are being monitored for sediment losses since a wildfire that occurred in July 2010. For reference, also a neighboring, long-unburnt eucalypt plantation is being monitored. The sediments collected by sediment fences were measured and collected at monthly intervals during the first 6 or 12 months after fire. The total carbon content of the sediment samples was measured using a Shimazdu TOC analyzer. Preliminary results revealed marked differences in organic carbon concentrations between the two burnt eucalypt stands

  8. Carbon partitioning in Arabidopsis thaliana is a dynamic process controlled by the plants metabolic status and its circadian clock

    Science.gov (United States)

    Kölling, Katharina; Thalmann, Matthias; Müller, Antonia; Jenny, Camilla; Zeeman, Samuel C

    2015-01-01

    Abstract Plant growth involves the coordinated distribution of carbon resources both towards structural components and towards storage compounds that assure a steady carbon supply over the complete diurnal cycle. We used 14CO2 labelling to track assimilated carbon in both source and sink tissues. Source tissues exhibit large variations in carbon allocation throughout the light period. The most prominent change was detected in partitioning towards starch, being low in the morning and more than double later in the day. Export into sink tissues showed reciprocal changes. Fewer and smaller changes in carbon allocation occurred in sink tissues where, in most respects, carbon was partitioned similarly, whether the sink leaf assimilated it through photosynthesis or imported it from source leaves. Mutants deficient in the production or remobilization of leaf starch exhibited major alterations in carbon allocation. Low-starch mutants that suffer from carbon starvation at night allocated much more carbon into neutral sugars and had higher rates of export than the wild type, partly because of the reduced allocation into starch, but also because of reduced allocation into structural components. Moreover, mutants deficient in the plant’s circadian system showed considerable changes in their carbon partitioning pattern suggesting control by the circadian clock. This work focusses on the temporal changes in the allocation and transport of photoassimilates within Arabidopsis rosettes, helping to fill a gap in our understanding of plant growth. Using short pulses of 14C-labelled carbon dioxide, we quantified how much carbon is used for growth and how much is stored as starch for use at night. In source leaves, partitioning is surprisingly dynamic during the day, even though photosynthesis is relatively constant, while in sink leaves, utilisation is more constant. Furthermore, by analysing metabolic mutants and clock mutants, and by manipulating the growth conditions, we show that

  9. Stable carbon and oxygen isotope record of central Lake Erie sediments

    Science.gov (United States)

    Tevesz, M.J.S.; Spongberg, A.L.; Fuller, J.A.

    1998-01-01

    Stable carbon and oxygen isotope data from mollusc aragonite extracted from sediment cores provide new information on the origin and history of sedimentation in the southwestern area of the central basin of Lake Erie. Sediments infilling the Sandusky subbasin consist of three lithologic units overlying glacial deposits. The lowest of these is a soft gray mud overlain by a shell hash layer containing Sphaerium striatinum fragments. A fluid mud unit caps the shell hash layer and extends upwards to the sediment-water interface. New stable isotope data suggest that the soft gray mud unit is of postglacial, rather than proglacial, origin. These data also suggest that the shell hash layer was derived from erosional winnowing of the underlying soft gray mud layer. This winnowing event may have occurred as a result of the Nipissing flood. The Pelee-Lorain moraine, which forms the eastern boundary of the Sandusky subbasin, is an elevated area of till capped by a sand deposit that originated as a beach. The presence of both the shell hash layer and relict beach deposit strengthens the interpretation that the Nipissing flood was a critical event in the development of the southwestern area of the central basin of Lake Erie. This event, which returned drainage from the upper lakes to the Lake Erie basin, was a dominant influence on regional stratigraphy, bathymetry, and depositional setting.

  10. Annual benthic metabolism and organic carbon fluxes in a semi-enclosed Mediterranean bay dominated by the macroalgae Caulerpa prolifera.

    Directory of Open Access Journals (Sweden)

    Sergio eRuiz-Halpern

    2014-12-01

    Full Text Available Coastal areas play an important role on carbon cycling. Elucidating the dynamics on the production, transport and fate of organic carbon is relevant to gain a better understanding of the role coastal areas play in the global carbon budget. Here, we assess the metabolic status and associated organic carbon fluxes of a semi-enclosed Mediterranean bay supporting a meadow of Caulerpa prolifera. We test whether the EDOC pool is a significant component of the organic carbon pool and associated fluxes in this ecosystem. The Bay of Portocolom was in net metabolic balance on a yearly basis, but heterotrophic during the summer months. Community respiration (CR was positively correlated to C. prolifera biomass, while net community production (NCP had a negative correlation. The benthic compartment represented, on average, 72.6 ± 5.2 % of CR and 86.8 ± 4.5 % of gross primary production (GPP. Dissolved organic carbon (DOC production peaked in summer and was always positive, with the incubations performed in the dark almost doubling the flux of those performed in the light. Exchangeable dissolved organic carbon (EDOC, however, oscillated between production and uptake, being completely recycled within the system and representing around 14% of the DOC flux. The pools of bottom and surface DOC were high for an oligotrophic environment, and were positively correlated to the pool of EDOC. Thus, despite being in metabolic balance, this ecosystem acted as a conduit for organic carbon (OC, as it is able to export OC to adjacent areas derived from allochtonous inputs during heterotrophic conditions. These inputs likely come from groundwater discharge, human activity in the watershed, delivered to the sediments through the high capacity of C. prolifera to remove particles from the water column, and from the air-water exchange of EDOC, demonstrating that these communities are a major contributor to the cycling of OC in coastal embayments.

  11. Planktic foraminifer and coccolith contribution to carbonate export fluxes over the central Kerguelen Plateau

    Science.gov (United States)

    Rembauville, M.; Meilland, J.; Ziveri, P.; Schiebel, R.; Blain, S.; Salter, I.

    2016-05-01

    We report the contribution of planktic foraminifers and coccoliths to the particulate inorganic carbon (PIC) export fluxes collected over an annual cycle (October 2011/September 2012) on the central Kerguelen Plateau in the Antarctic Zone (AAZ) south of the Polar Front (PF). The seasonality of PIC flux was decoupled from surface chlorophyll a concentration and particulate organic carbon (POC) fluxes and was characterized by a late summer (February) maximum. This peak was concomitant with the highest satellite-derived sea surface PIC and corresponded to a Emiliania huxleyi coccoliths export event that accounted for 85% of the annual PIC export. The foraminifer contribution to the annual PIC flux was much lower (15%) and dominated by Turborotalita quinqueloba and Neogloboquadrina pachyderma. Foraminifer export fluxes were closely related to the surface chlorophyll a concentration, suggesting food availability as an important factor regulating the foraminifer's biomass. We compared size-normalized test weight (SNW) of the foraminifers with previously published SNW from the Crozet Islands using the same methodology and found no significant difference in SNW between sites for a given species. However, the SNW was significantly species-specific with a threefold increase from T. quinqueloba to Globigerina bulloides. The annual PIC:POC molar ratio of 0.07 was close to the mean ratio for the global ocean and lead to a low carbonate counter pump effect (~5%) compared to a previous study north of the PF (6-32%). We suggest that lowers counter pump effect south of the PF despite similar productivity levels is due to a dominance of coccoliths in the PIC fluxes and a difference in the foraminifers species assemblage with a predominance of polar species with lower SNW.

  12. Contribution of carbon fixed by Rubisco and PEPC to phloem export in the Crassulacean acid metabolism plant Kalanchoe daigremontiana.

    Science.gov (United States)

    Wild, Birgit; Wanek, Wolfgang; Postl, Wolfgang; Richter, Andreas

    2010-03-01

    Crassulacean acid metabolism (CAM) plants exhibit a complex interplay between CO(2) fixation by phosphoenolpyruvate carboxylase (PEPC) and ribulose-1,5-bisphosphate carboxylase oxygenase (Rubisco), and carbon demand for CAM maintenance and growth. This study investigated the flux of carbon from PEPC and direct Rubisco fixation to different leaf carbon pools and to phloem sap over the diurnal cycle. Concentrations and carbon isotope compositions of starch, soluble sugars, and organic acids were determined in leaves and phloem exudates of Kalanchoë daigremontiana Hamet et Perr., and related to CO(2) fixation by PEPC and Rubisco. Three types of leaf carbon pools could be distinguished. (i) Starch and malate pools were dominant and showed a pattern of reciprocal mobilization and accumulation (85/54 and 13/48 mg C g(-1) DW, respective, at the beginning/end of phase I). The carbon isotope composition of these pools was compatible with predominant PEPC fixation (delta(13)C values of -13 and -11 per thousand for starch and malate compared to -11 per thousand of PEPC fixed carbon). (ii) Isotopic composition (-17 per thousand and -14 per thousand) and concentration of glucose and fructose (2 and 3 mg C g(-1) DW, respectively) were not affected by diurnal metabolism, suggesting a low turnover. (iii) Sucrose (1-3 mg C g(-1) DW), in contrast, exhibited large diurnal changes in delta(13)C values (from -17 per thousand in the evening to -12 per thousand in the morning), which were not matched by net changes in sucrose concentration. This suggests a high sucrose turnover, fed by nocturnal starch degradation and direct Rubisco fixation during the day. A detailed dissection of the carbon fixation and mobilization pattern in K. daigremontiana revealed that direct fixation of Rubisco during the light accounted for 30% of phloem sucrose, but only 15% of fixed carbon, indicating that carbon from direct Rubisco fixation was preferentially used for leaf export. PMID:20159885

  13. Cannabis, Cannabinoids, and Cerebral Metabolism: Potential Applications in Stroke and Disorders of the Central Nervous System.

    Science.gov (United States)

    Latorre, Julius Gene S; Schmidt, Elena B

    2015-09-01

    No compound has generated more attention in both the scientific and recently in the political arena as much as cannabinoids. These diverse groups of compounds referred collectively as cannabinoids have both been vilified due to its dramatic and potentially harmful psychotropic effects and glorified due to its equally dramatic and potential application in a number of acute and chronic neurological conditions. Previously illegal to possess, cannabis, the plant where natural form of cannabinoids are derived, is now accepted in a growing number of states for medicinal purpose, and some even for recreational use, increasing opportunities for more scientific experimentation. The purpose of this review is to summarize the growing body of literature on cannabinoids and to present an overview of our current state of knowledge of the human endocannabinoid system in the hope of defining the future of cannabinoids and its potential applications in disorders of the central nervous system, focusing on stroke. PMID:26238742

  14. The central role of chloride in the metabolic acid-base changes in canine parvoviral enteritis.

    Science.gov (United States)

    Burchell, Richard K; Schoeman, Johan P; Leisewitz, Andrew L

    2014-04-01

    The acid-base disturbances in canine parvoviral (CPV) enteritis are not well described. In addition, the mechanisms causing these perturbations have not been fully elucidated. The purpose of the present study was to assess acid-base changes in puppies suffering from CPV enteritis, using a modified strong ion model (SIM). The hypothesis of the study was that severe acid-base disturbances would be present and that the SIM would provide insights into pathological mechanisms, which have not been fully appreciated by the Henderson-Hasselbalch model. The study analysed retrospective data, obtained from 42 puppies with confirmed CPV enteritis and 10 healthy control dogs. The CPV-enteritis group had been allocated a clinical score, to allow classification of the data according to clinical severity. The effects of changes in free water, chloride, l-lactate, albumin and phosphate were calculated, using a modification of the base excess algorithm. When the data were summated for each patient, and correlated to each individual component, the most important contributor to the metabolic acid-base changes, according to the SIM, was chloride (Penteritis are multifactorial and complex, with the SIM providing information in terms of the origin of these changes.

  15. Oxygen-18 incorporation into malic acid during nocturnal carbon dioxide fixation in crassulacean acid metabolism plants: a new approach to estimating in vivo carbonic anhydrase activity

    Energy Technology Data Exchange (ETDEWEB)

    Holtum, J.A.M.; Summons, R.; Roeske, C.A.; Comins, H.N.; O' Leary, M.H.

    1984-01-01

    Crassulacean acid metabolism (CAM) plants fix carbon dioxide at night by the carboxylation of phosphoenolpyruvate. If CO2 fixation is conducted with TC YO2, then in the absence of carbonic anhydrase, the malate formed by dark CO2 fixation should also contain high levels of carbon-13 and oxygen-18. Conversely, if carbonic anhydrase is present and highly active, oxygen exchange between CO2 and cellular H2O will occur more rapidly than carboxylation, and the ( TC) malate formed will contain little or no oxygen-18 above the natural abundance level. The presence of oxygen-18 in these molecules can be detected either by nuclear magnetic resonance or by mass spectrometry. Studies of phosphoenolpyruvate carboxylase in the presence and absence of carbonic anhydrase in vitro confirm the validity of the method. When CAM plants are studied by this method, we find that most species show incorporation of a significant amount of oxygen-18. Comparison of these results with results of isotope fractionation and gas exchange studies permits calculation of the in vivo activity of carbonic anhydrase toward HCO3 compared with that of phosphoenolpyruvate carboxylase. The ratio (carbonic anhydrase activity/phosphoenolpyruvate carboxylase activity) is species dependent and varies from a low of about 7 for Ananas comosus to values near 20 for Hoya carnosa and Bryophyllum pinnatum, 40 for Kalanchoee daigremontiana, and 100 or greater for Bryophyllum tubiflorum, Kalanchoee serrata, and Kalanchoae tomentosa. Carbonic anhydrase activity increases relative to phosphoenolpyruvate carboxylase activity at higher temperature. 37 references, 2 figures, 8 tables.

  16. Neurochemistry of Pressure-Induced Nitrogen and Metabolically Inert Gas Narcosis in the Central Nervous System.

    Science.gov (United States)

    Rostain, Jean-Claude; Lavoute, Cécile

    2016-01-01

    Gases that are not metabolized by the organism are thus chemically inactive under normal conditions. Such gases include the "noble gases" of the Periodic Table as well as hydrogen and nitrogen. At increasing pressure, nitrogen induces narcosis at 4 absolute atmospheres (ATAs) and more in humans and at 11 ATA and more in rats. Electrophysiological and neuropharmacological studies suggest that the striatum is a target of nitrogen narcosis. Glutamate and dopamine release from the striatum in rats are decreased by exposure to nitrogen at a pressure of 31 ATA (75% of the anesthetic threshold). Striatal dopamine levels decrease during exposure to compressed argon, an inert gas more narcotic than nitrogen, or to nitrous oxide, an anesthetic gas. Inversely, striatal dopamine levels increase during exposure to compressed helium, an inert gas with a very low narcotic potency. Exposure to nitrogen at high pressure does not change N-methyl-d-aspartate (NMDA) glutamate receptor activities in Substantia Nigra compacta and striatum but enhances gama amino butyric acidA (GABAA) receptor activities in Substantia Nigra compacta. The decrease in striatal dopamine levels in response to hyperbaric nitrogen exposure is suppressed by recurrent exposure to nitrogen narcosis, and dopamine levels increase after four or five exposures. This change, the lack of improvement of motor disturbances, the desensitization of GABAA receptors on dopamine cells during recurrent exposures and the long-lasting decrease of glutamate coupled with the higher sensitivity of NMDA receptors, suggest a nitrogen toxicity induced by repetitive exposures to narcosis. These differential changes in different neurotransmitter receptors would support the binding protein theory. © 2016 American Physiological Society. Compr Physiol 6:1579-1590, 2016. PMID:27347903

  17. Comparative genomic reconstruction of transcriptional networks controlling central metabolism in the Shewanella genus

    Energy Technology Data Exchange (ETDEWEB)

    Rodionov, Dmitry A.; Novichkov, Pavel; Stavrovskaya, Elena D.; Rodionova, Irina A.; Li, Xiaoqing; Kazanov, Marat D.; Ravcheev, Dmitry A.; Gerasimova, Anna V.; Kazakov, Alexey E.; Kovaleva, Galina Y.; Permina, Elizabeth A.; Laikova, Olga N.; Overbeek, Ross; Romine, Margaret F.; Fredrickson, Jim K.; Arkin, Adam P.; Dubchak, Inna; Osterman, Andrei L.; Gelfand, Mikhail S.

    2011-06-15

    Genome-scale prediction of gene regulation and reconstruction of transcriptional regulatory networks in bacteria is one of the critical tasks of modern genomics. Despite the growing number of genome-scale gene expression studies, our abilities to convert the results of these studies into accurate regulatory annotations and to project them from model to other organisms are extremely limited. The comparative genomics approaches and computational identification of regulatory sites are useful for the in silico reconstruction of transcriptional regulatory networks in bacteria. The Shewanella genus is comprised of metabolically versatile gamma-proteobacteria, whose lifestyles and natural environments are substantially different from Escherichia coli and other model bacterial species. To explore conservation and variations in the Shewanella transcriptional networks we analyzed the repertoire of transcription factors and performed genomics-based reconstruction and comparative analysis of regulons in 16 Shewanella genomes. The inferred regulatory network includes 82 transcription factors and their DNA binding sites, 8 riboswitches and 6 translational attenuators. Forty five regulons were newly inferred from the genome context analysis, whereas others were propagated from previously characterized regulons in the Enterobacteria and Pseudomonas spp.. However, even orthologous regulators with conserved DNA-binding motifs may control substantially different gene sets, revealing striking differences in regulatory strategies between the Shewanella spp. and E. coli. Multiple examples of regulatory network rewiring include regulon contraction and expansion (as in the case of PdhR, HexR, FadR), and numerous cases of recruiting non-orthologous regulators to control equivalent pathways (e.g. NagR for N-acetylglucosamine catabolism and PsrA for fatty acid degradation) and, conversely, orthologous regulators to control distinct pathways (e.g. TyrR, ArgR, Crp).

  18. Effect of Mitochondrial Dysfunction on Carbon Metabolism and Gene Expression in Flower Tissues of Arabidopsis thaliana

    Institute of Scientific and Technical Information of China (English)

    Maria V.Busi; Maria E.Gomez-Lobato; Sebastian P.Rius; Valeria R.Turowski; Paula Casati; Eduardo J.Zabaleta; Diego F.Gomez-Casati; Alejandro Araya

    2011-01-01

    We characterized the transcriptomic response of transgenic plants carrying a mitochondrial dysfunction induced by the expression of the unedited form of the ATP synthase subunit 9.The u-ATP9 transgene driven by A9 and APETALA3 promoters induce mitochondrial dysfunction revealed by a decrease jn both oxygen uptake and adenine nucleotides(ATP,ADP)levels without changes in the ATP/ADP ratio.Furthermore,we measured an increase in ROS accumulation and a decrease in glutathione and ascorbate levels with a concomitant oxidative stress response.The transcriptome analysis of young Arabidopsis flowers,validated by Qrt-PCR and enzymatic or functional tests,showed dramatic changes in u-ATP9 plants.Both lines display a modification in the expression of various genes involved in carbon,lipid,and cell wall metabolism,suggesting that an important metabolic readjustment occurs in plants with a mitochondrial dysfunction.Interestingly,transcript levels involved in mitochondrial respiration,protein synthesis,and degradation are affected.Moreover,the Ievels of several mRNAs encoding for transcription factors and DNA binding proteins were also changed.Some of them are involved in stress and hormone responses,suggesting that several signaling pathways overlap.Indeed,the transcriptome data revealed that the mitochondrial dysfunction dramatically alters the expression of genes involved in signaling pathways,including those related to ethylene,absicic acid,and auxin signal transduction.Our data suggest that the mitochondrial dysfunction model used in this report may be usefuI to uncover the retrograde signaling mechanism between the nucleus and mitochondria in plant cells.

  19. Biochemical hydrogen isotope fractionation during biosynthesis in higher plants reflects carbon metabolism of the plant

    Science.gov (United States)

    Cormier, Marc-André; Kahmen, Ansgar

    2015-04-01

    Compound-specific isotope analyses of plant material are frequently applied to understand the response of plants to the environmental changes. As it is generally assume that the main factors controlling δ2H values in plants are the plant's source water and evaporative deuterium enrichment of leaf water, hydrogen isotope analyses of plant material are mainly applied regarding hydrological conditions at different time scales. However, only few studies have directly addressed the variability of the biochemical hydrogen isotope fractionation occurring during biosynthesis of organic compounds (ɛbio), accounting also for a large part in the δ2H values of plants but generally assumed to be constant. Here we present the results from a climate-controlled growth chambers experiment where tested the sensitivity of ɛbio to different light treatments. The different light treatments were applied to induce different metabolic status (autotrophic vs. heterotrophic) in 9 different plant species that we grew from large storage organs (e.g. tubers or roots). The results show a systematic ɛbio shift (up to 80 ) between the different light treatments for different compounds (i.e. long chain n-alkanes and cellulose). We suggest that this shift is due to the different NADPH pools used by the plants to build up the compounds from stored carbohydrates in heterotrophic or autotrophic conditions. Our results have important implications for the calibration and interpretation of sedimentary and tree rings records in geological studies. In addition, as the δ2H values reflect also strongly the carbon metabolism of the plant, our findings support the idea of δ2H values as an interesting proxy for plant physiological studies.

  20. Metabolic peculiarity of 134Cs and its radioimmunotoxicological effect on central and peripheral immune cells

    Institute of Scientific and Technical Information of China (English)

    朱寿彭; 夏芬

    1996-01-01

    A fitted equation with least square method to describe the retention of 134Cs in whole body is obtained by a whole body counter.That is R(t)=18.04exp(-9.3175t)+ 45.13exp(-0.0423t),where R(t) is in %,and t in d.The equationn consists of two half-life components,the fast component is T1/2=0.07d,and the slow is T1/2=16.14d,Study on the localization of 134Cs at cellular level was carried out by freezing microautoradiography.The results indicate of 134Cs at cellular level was carried out by freezing microautoradiography.The results indicate that 134Cs was chiefly in ionizing form accumulated in red as well as white blood cells.In bone marrow cells 134Cs predominantly deposited in young cells and less in mature cells.Distribution of 134Cs penetrated quickly into the tissue cells.The observation of investigating radioimmunotoxicological effect induced by 134Cs shows that the inhibition of thymocytes is higher than bone marrow cells,the spleen T lynmphocytes are more sensitive to 134Cs than B lymphocytes and lymphocytes of peripheral immune cells are more sensitive to radiation than central immune cells.

  1. Anaerobic hydrocarbon and fatty acid metabolism by syntrophic bacteria and their impact on carbon steel corrosion

    Directory of Open Access Journals (Sweden)

    Christopher Neil Lyles

    2014-04-01

    Full Text Available The microbial metabolism of hydrocarbons is increasingly associated with the corrosion of carbon steel in sulfate-rich marine waters. However, how such transformations influence metal biocorrosion in the absence of an electron acceptor is not fully recognized. We grew a marine alkane-utilizing, sulfate-reducing bacterium, Desulfoglaeba alkanexedens, with either sulfate or Methanospirillum hungatei as electron acceptors, and tested the ability of the cultures to catalyze metal corrosion. Axenically, D. alkanexedens had a higher instantaneous corrosion rate and produced more pits in carbon steel coupons than when the same organism was grown in syntrophic co-culture with the methanogen. Since anaerobic hydrocarbon biodegradation pathways converge on fatty acid intermediates, the corrosive ability of a known fatty acid-oxidizing syntrophic bacterium, Syntrophus aciditrophicus was compared when grown in pure culture or in co-culture with a H2-utilizing sulfate-reducing bacterium (Desulfovibrio sp., strain G11 or a methanogen (M. hungatei. The instantaneous corrosion rates in the cultures were not substantially different, but the syntrophic, sulfate-reducing co-culture produced more pits in coupons than other combinations of microorganisms. Lactate-grown cultures of strain G11 had higher instantaneous corrosion rates and coupon pitting compared to the same organism cultured with hydrogen as an electron donor. Thus, if sulfate is available as an electron acceptor, the same microbial assemblages produce sulfide and low molecular weight organic acids that exacerbated biocorrosion. Despite these trends, a surprisingly high degree of variation was encountered with the corrosion assessments. Differences in biomass, initial substrate concentration, rates of microbial activity or the degree of end product formation did not account for the variations. We are forced to ascribe such differences to the metallurgical properties of the coupons.

  2. Anaerobic hydrocarbon and fatty acid metabolism by syntrophic bacteria and their impact on carbon steel corrosion.

    Science.gov (United States)

    Lyles, Christopher N; Le, Huynh M; Beasley, William Howard; McInerney, Michael J; Suflita, Joseph M

    2014-01-01

    The microbial metabolism of hydrocarbons is increasingly associated with the corrosion of carbon steel in sulfate-rich marine waters. However, how such transformations influence metal biocorrosion in the absence of an electron acceptor is not fully recognized. We grew a marine alkane-utilizing, sulfate-reducing bacterium, Desulfoglaeba alkanexedens, with either sulfate or Methanospirillum hungatei as electron acceptors, and tested the ability of the cultures to catalyze metal corrosion. Axenically, D. alkanexedens had a higher instantaneous corrosion rate and produced more pits in carbon steel coupons than when the same organism was grown in syntrophic co-culture with the methanogen. Since anaerobic hydrocarbon biodegradation pathways converge on fatty acid intermediates, the corrosive ability of a known fatty acid-oxidizing syntrophic bacterium, Syntrophus aciditrophicus was compared when grown in pure culture or in co-culture with a H2-utilizing sulfate-reducing bacterium (Desulfovibrio sp., strain G11) or a methanogen (M. hungatei). The instantaneous corrosion rates in the cultures were not substantially different, but the syntrophic, sulfate-reducing co-culture produced more pits in coupons than other combinations of microorganisms. Lactate-grown cultures of strain G11 had higher instantaneous corrosion rates and coupon pitting compared to the same organism cultured with hydrogen as an electron donor. Thus, if sulfate is available as an electron acceptor, the same microbial assemblages produce sulfide and low molecular weight organic acids that exacerbated biocorrosion. Despite these trends, a surprisingly high degree of variation was encountered with the corrosion assessments. Differences in biomass, initial substrate concentration, rates of microbial activity or the degree of end product formation did not account for the variations. We are forced to ascribe such differences to the metallurgical properties of the coupons.

  3. New concepts of the central control of reproduction, integrating influence of stress, metabolic state, and season.

    Science.gov (United States)

    Clarke, I J; Arbabi, L

    2016-07-01

    Gonadotropin releasing hormone is the primary driver of reproductive function and pulsatile GnRH secretion from the brain causes the synthesis and secretion of LH and FSH from the pituitary gland. Recent work has revealed that the secretion of GnRH is controlled at the level of the GnRH secretory terminals in the median eminence. At this level, projections of kisspeptin cells from the arcuate nucleus of the hypothalamus are seen to be closely associated with fibers and terminals of GnRH cells. Direct application of kisspeptin into the median eminence causes release of GnRH. The kisspeptin cells are activated at the time of a natural "pulse" secretion of GnRH, as reflected in the secretion of LH. This appears to be due to input to the kisspeptin cells from glutamatergic cells in the basal hypothalamus, indicating that more than 1 neural element is involved in the secretion of GnRH. Because the GnRH secretory terminals are outside the blood-brain barrier, factors such as kisspeptin may be administered systemically to cause GnRH secretion; this offers opportunities for manipulation of the reproductive axis using factors that do not cross the blood-brain barrier. In particular, kisspeptin or analogs of the same may be used to activate reproduction in the nonbreeding season of domestic animals. Another brain peptide that influences reproductive function is gonadotropin inhibitory hormone (GnIH). Work in sheep shows that this peptide acts on GnRH neuronal perikarya, but projections to the median eminence also allow secretion into the hypophysial portal blood and action of GnIH on pituitary gonadotropes. GnIH cells are upregulated in anestrus, and infusion of GnIH can block the ovulatory surge in GnRH and/or LH secretion. Metabolic status may also affect the secretion of reproduction, and this could involve action of gut peptides and leptin. Neuropeptide Y and Y-receptor ligands have a negative impact on reproduction, and Neuropeptide Y production is markedly increased in

  4. The effects of lead on the gaseous exchange and photosynthetic carbon metabolism of pea seedlings

    Directory of Open Access Journals (Sweden)

    Jerzy W. Poskuta

    2014-02-01

    Full Text Available Roots of whole 3 week-old pea seedlings (Pisum sativum L. var. "Bordi" were immersed for 24 h in solutions of lead chloride at Pb copcentrations of 200, 400, 800,12000 mg dm3. Accumulation of lead in roots was independent of the Pb concentration, whereas the accumulation of Pb in shoots was an almost linear function of the concentration of this element in the root medium. This treatment caused Pb concentration-dependent inhibition of apparent photosynthesis (APS, photorespiration (PR, 14CO2 uptake, stomatal opening and transpiration of shoots and also germination of seeds. The most sensitive to Pb contamination was CO2 exchange, then transpiration and to a lesser degree germination of seeds. Lead caused a considerable alteration of photosynthetic and photorespiratory carbon metabolism, restricted the 14C-labeling of: phosphoglycerate, ribose+ribulose, sucrose, glycolate and glycine+serine. Under conditions of C02 uptake limited by lead, an enhancement of the 14C-labeling of malate+citrate, alanine and glucose was observed.

  5. 2004 Molecular Basis of Microbial One-Carbon Metabolism Gordon Conference - August 1-6, 2004

    Energy Technology Data Exchange (ETDEWEB)

    Joseph A. Krzycki

    2005-09-15

    The Gordon Research Conference (GRC) on 2004 Molecular Basis of Microbial One-Carbon Metabolism Gordon Conference - August 1-6, 2004 was held at Mount Holyoke College, South Hadley, MA from August 1-6, 2004. The Conference was well-attended with 117 participants (attendees list attached). The attendees represented the spectrum of endeavor in this field coming from academia, industry, and government laboratories, both U.S. and foreign scientists, senior researchers, young investigators, and students. In designing the formal speakers program, emphasis was placed on current unpublished research and discussion of the future target areas in this field. There was a conscious effort to stimulate lively discussion about the key issues in the field today. Time for formal presentations was limited in the interest of group discussions. In order that more scientists could communicate their most recent results, poster presentation time was scheduled. Attached is a copy of the formal schedule and speaker program and the poster program. In addition to these formal interactions, 'free time' was scheduled to allow informal discussions. Such discussions are fostering new collaborations and joint efforts in the field.

  6. Oxygen-18 incorporation into malic acid during nocturnal carbon dioxide fixation in crassulacean acid metabolism plants. A new approach to estimating in vivo carbonic anhydrase activity.

    Science.gov (United States)

    Holtum, J A; Summons, R; Roeske, C A; Comins, H N; O'Leary, M H

    1984-06-10

    Crassulacean acid metabolism (CAM) plants fix carbon dioxide at night by the carboxylation of phosphoenolpyruvate. If CO2 fixation is conducted with 13C18O2 , then in the absence of carbonic anhydrase, the malate formed by dark CO2 fixation should also contain high levels of carbon-13 and oxygen-18. Conversely, if carbonic anhydrase is present and highly active, oxygen exchange between CO2 and cellular H2O will occur more rapidly than carboxylation, and the [13C] malate formed will contain little or no oxygen-18 above the natural abundance level. The presence of oxygen-18 in these molecules can be detected either by nuclear magnetic resonance (using the oxygen-18 effect on the carbon-13 chemical shift of the carboxyl carbon) or by mass spectrometry (comparing the ions at three and five units above the molecular weight with that one unit above). Studies of phosphoenolpyruvate carboxylase in the presence and absence of carbonic anhydrase in vitro confirm the validity of the method. When CAM plants are studied by this method, we find that most species show incorporation of a significant amount of oxygen-18. Comparison of these results with results of isotope fractionation and gas exchange studies permits calculation of the in vivo activity of carbonic anhydrase toward HCO-3 compared with that of phosphoenolpyruvate carboxylase. The ratio (carbonic anhydrase activity/phosphoenolpyruvate carboxylase activity) is species dependent and varies from a low of about 7 for Ananas comosus to values near 20 for Hoya carnosa and Bryophyllum pinnatum , 40 for Kalancho ë daigremontiana , and 100 or greater for Bryophyllum tubiflorum , Kalancho ë serrata, and Kalancho ë tomentosa. Carbonic anhydrase activity increases relative to phosphoenolpyruvate carboxylase activity at higher temperature. PMID:6427227

  7. Carbon Flux of Down Woody Materials in Forests of the North Central United States

    International Nuclear Information System (INIS)

    Across large scales, the carbon (C) flux of down woody material (DWM) detrital pools has largely been simulated based on forest stand attributes (e.g., stand age and forest type). The annual change in forest DWM C stocks and other attributes (e.g., size and decay class changes) was assessed using a forest inventory in the north central United States to provide an empirical assessment of strategic-scale DWM C flux. Using DWM inventory data from the USDA Forest Service's Forest Inventory and Analysis program, DWM C stocks were found to be relatively static across the study region with an annual flux rate not statistically different from zero. Mean C flux rates across the study area were -0.25, -0.12, -0.01, and -0.04 (Mg/ha/yr) for standing live trees, standing dead trees, coarse woody debris, and fine woody debris, respectively. Flux rates varied in their both magnitude and status (emission/sequestration) by forest types, latitude, and DWM component size. Given the complex dynamics of DWM C flux, early implementation of inventory re measurement, and relatively low sample size, numerous future research directions are suggested.

  8. Isotopic characterization of the Precambrian carbonate aquifers under the city of Bangui (Central African Republic)

    Science.gov (United States)

    Huneau, Frederic; Djebebe-Ndjiguim, Chantal-Laure; Foto, Eric; Ito, Mari; Celle-Jeanton, Helene; Garel, Emilie; Mabingui, Joseph

    2013-04-01

    The city of Bangui, the capital of the Central African Republic, is located on the right bank of the Ubangi River which is the northernmost tributary of the Congo River. From its foundation in 1889 this city has always suffered from serious problems of water management. This is related to the specificity of the site configuration (steep hills surrounding a large swampy flat valley poorly drained) and to the urbanisation process responsible for the waterproofing of soils and the associated increased runoff processes under tropical humid condition.This paper presents the results of a geochemical and isotopic survey carried out in 2011 aiming at evaluating the type and chemical quality of the groundwater resources of the Bangui region. By combining geological, hydrogeochemical and isotopic data it appears that the underground of Bangui seems favourable to the development of a secured and sustainable water supply from groundwater provided that the conditions of exploitation would be constrained by the local authorities. The deep fractured (and locally kastified) Precambrian carbonate aquifers known as Bimbo and Fatima formations are identified as target resources considering the relatively good quality of the resource from the chemical point of view, and the semi-confined structure of the aquifer preventing the mixing with shallow aquifers already strongly impacted by domestic and industrial pollutions.

  9. Application of artificial neural networks to investigate one-carbon metabolism in Alzheimer's disease and healthy matched individuals.

    Directory of Open Access Journals (Sweden)

    Fabio Coppedè

    Full Text Available Folate metabolism, also known as one-carbon metabolism, is required for several cellular processes including DNA synthesis, repair and methylation. Impairments of this pathway have been often linked to Alzheimer's disease (AD. In addition, increasing evidence from large scale case-control studies, genome-wide association studies, and meta-analyses of the literature suggest that polymorphisms of genes involved in one-carbon metabolism influence the levels of folate, homocysteine and vitamin B12, and might be among AD risk factors. We analyzed a dataset of 30 genetic and biochemical variables (folate, homocysteine, vitamin B12, and 27 genotypes generated by nine common biallelic polymorphisms of genes involved in folate metabolism obtained from 40 late-onset AD patients and 40 matched controls to assess the predictive capacity of Artificial Neural Networks (ANNs in distinguish consistently these two different conditions and to identify the variables expressing the maximal amount of relevant information to the condition of being affected by dementia of Alzheimer's type. Moreover, we constructed a semantic connectivity map to offer some insight regarding the complex biological connections among the studied variables and the two conditions (being AD or control. TWIST system, an evolutionary algorithm able to remove redundant and noisy information from complex data sets, selected 16 variables that allowed specialized ANNs to discriminate between AD and control subjects with over 90% accuracy. The semantic connectivity map provided important information on the complex biological connections among one-carbon metabolic variables highlighting those most closely linked to the AD condition.

  10. Effects of oxidative stress on fatty acid- and one-carbon-metabolism in psychiatric and cardiovascular disease comorbidity

    OpenAIRE

    Assies, J.; Mocking, R J T; Lok, A; Ruhé, H.G.; Pouwer, F.; Schene, A. H.

    2014-01-01

    Objective Cardiovascular disease (CVD) is the leading cause of death in severe psychiatric disorders (depression, schizophrenia). Here, we provide evidence of how the effects of oxidative stress on fatty acid (FA) and one-carbon (1-C) cycle metabolism, which may initially represent adaptive responses, might underlie comorbidity between CVD and psychiatric disorders. Method We conducted a literature search and integrated data in a narrative review. Results Oxidative stress, mainly generated in...

  11. Central obesity and atherogenic dyslipidemia in metabolic syndrome are associated with increased risk for colorectal adenoma in a Chinese population

    Directory of Open Access Journals (Sweden)

    Lin Tsann

    2010-05-01

    Full Text Available Abstract Background Metabolic syndrome (MetS is composed of cardiovascular risk factors including insulin resistance, obesity, dyslipidemia, and hypertension. Most of the components of MetS have been linked to the development of neoplasm. The purpose of this study was to evaluate the relationship between individual components of MetS and colorectal adenoma. Methods The study subjects were recruited from a pool of 4872 individuals who underwent a health check-up examination during the period January 2006 to May 2008. Each participant fulfilled a structured questionnaire. MetS was defined based on the America Heart Association and National Heart Lung Blood Institute criteria. Subjects with history of colon cancer, colon polyps, colitis, or prior colonic surgery were excluded. Results A total of 4122 subjects were included for final analysis (2367 men and 1755 women; mean age, 49.6 ± 11.7 years. Of them, MetS was diagnosed in 708 men (29.9% and in 367 women (20.9%. Among the patients with MetS, 34.6% had adenoma, 31.7% had hyperplastic polyps and 23.3% were polyp-free (p Conclusions Of the components of MetS analyzed in this study, central obesity and dyslipidemia are independent risk factors for colorectal adenoma. With regard to the prevention of colorectal neoplasm, life-style modification such as weight reduction is worthwhile.

  12. Contribution of carbon fixed by Rubisco and PEPC to phloem export in the Crassulacean acid metabolism plant Kalanchoë daigremontiana

    OpenAIRE

    Wild, Birgit; Wanek, Wolfgang; Postl, Wolfgang; Richter, Andreas

    2010-01-01

    Crassulacean acid metabolism (CAM) plants exhibit a complex interplay between CO2 fixation by phosphoenolpyruvate carboxylase (PEPC) and ribulose-1,5-bisphosphate carboxylase oxygenase (Rubisco), and carbon demand for CAM maintenance and growth. This study investigated the flux of carbon from PEPC and direct Rubisco fixation to different leaf carbon pools and to phloem sap over the diurnal cycle. Concentrations and carbon isotope compositions of starch, soluble sugars, and organic acids were ...

  13. Carbon Disulfide (CS2) Interference in Glucose Metabolism from Unconventional Oil and Gas Extraction and Processing Emissions.

    Science.gov (United States)

    Rich, Alisa L; Patel, Jay T; Al-Angari, Samiah S

    2016-01-01

    Carbon disulfide (CS2) has been historically associated with the manufacturing of rayon, cellophane, and carbon tetrachloride production. This study is one of the first to identify elevated atmospheric levels of CS2 above national background levels and its mechanisms to dysregulate normal glucose metabolism. Interference in glucose metabolism can indirectly cause other complications (diabetes, neurodegenerative disease, and retinopathy), which may be preventable if proper precautions are taken. Rich et al found CS2 and 12 associated sulfide compounds present in the atmosphere in residential areas where unconventional shale oil and gas extraction and processing operations were occurring. Ambient atmospheric concentrations of CS2 ranged from 0.7 parts per billion by volume (ppbv) to 103 ppbv over a continuous 24-hour monitoring period. One-hour ambient atmospheric concentrations ranged from 3.4 ppbv to 504.6 ppbv. Using the U.S. Environmental Protection Agency Urban Air Toxic Monitoring Program study as a baseline comparison for atmospheric CS2 concentrations found in this study, it was determined that CS2 atmospheric levels were consistently elevated in areas where unconventional oil and gas extraction and processing occurred. The mechanisms by which CS2 interferes in normal glucose metabolism by dysregulation of the tryptophan metabolism pathway are presented in this study. The literature review found an increased potential for alteration of normal glucose metabolism in viscose rayon occupational workers exposed to CS2. Occupational workers in the energy extraction industry exposed to CS2 and other sulfide compounds may have an increased potential for glucose metabolism interference, which has been an indicator for diabetogenic effect and other related health impacts. The recommendation of this study is for implementation of regular monitoring of blood glucose levels in CS2-exposed populations as a preventative health measure.

  14. [Carbon source metabolic diversity of soil microbial community under different climate types in the area affected by Wenchuan earthquake].

    Science.gov (United States)

    Zhang, Guang-Shuai; Lin, Yong-Ming; Ma, Rui-Feng; Deng, Hao-Jun; Du, Kun; Wu, Cheng-Zhen; Hong, Wei

    2015-02-01

    The MS8.0 Wenchuan earthquake in 2008 led to huge damage to land covers in northwest Sichuan, one of the critical fragile eco-regions in China which can be divided into Semi-arid dry hot climate zone (SDHC) and Subtropical humid monsoon climate zone (SHMC). Using the method of Bilog-ECO-microplate technique, this paper aimed to determine the functional diversity of soil microbial community in the earthquake-affected areas which can be divided into undamaged area (U), recover area (R) and damaged area without recovery (D) under different climate types, in order to provide scientific basis for ecological recovery. The results indicated that the average-well-color-development (AWCD) in undamaged area and recovery area showed SDHC > SHMC, which was contrary to the AWCD in the damaged area without recovery. The AWCD of damaged area without recovery was the lowest in both climate zones. The number of carbon source utilization types of soil microbial in SHMC zone was significantly higher than that in SDHC zone. The carbon source utilization types in both climate zones presented a trend of recover area > undamaged area > damaged area without recovery. The carbon source metabolic diversity characteristic of soil microbial community was significantly different in different climate zones. The diversity index and evenness index both showed a ranking of undamaged area > recover area > damaged area without recovery. In addition, the recovery area had the highest richness index. The soil microbial carbon sources metabolism characteristic was affected by soil nutrient, aboveground vegetation biomass and vegetation coverage to some extent. In conclusion, earthquake and its secondary disasters influenced the carbon source metabolic diversity characteristic of soil microbial community mainly through the change of aboveground vegetation and soil environmental factors. PMID:26031097

  15. 13C-metabolic flux ratio and novel carbon path analyses confirmed that Trichoderma reesei uses primarily the respirative pathway also on the preferred carbon source glucose

    Directory of Open Access Journals (Sweden)

    Saloheimo Markku

    2009-10-01

    Full Text Available Abstract Background The filamentous fungus Trichoderma reesei is an important host organism for industrial enzyme production. It is adapted to nutrient poor environments where it is capable of producing large amounts of hydrolytic enzymes. In its natural environment T. reesei is expected to benefit from high energy yield from utilization of respirative metabolic pathway. However, T. reesei lacks metabolic pathway reconstructions and the utilization of the respirative pathway has not been investigated on the level of in vivo fluxes. Results The biosynthetic pathways of amino acids in T. reesei supported by genome-level evidence were reconstructed with computational carbon path analysis. The pathway reconstructions were a prerequisite for analysis of in vivo fluxes. The distribution of in vivo fluxes in both wild type strain and cre1, a key regulator of carbon catabolite repression, deletion strain were quantitatively studied by performing 13C-labeling on both repressive carbon source glucose and non-repressive carbon source sorbitol. In addition, the 13C-labeling on sorbitol was performed both in the presence and absence of sophorose that induces the expression of cellulase genes. Carbon path analyses and the 13C-labeling patterns of proteinogenic amino acids indicated high similarity between biosynthetic pathways of amino acids in T. reesei and yeast Saccharomyces cerevisiae. In contrast to S. cerevisiae, however, mitochondrial rather than cytosolic biosynthesis of Asp was observed under all studied conditions. The relative anaplerotic flux to the TCA cycle was low and thus characteristic to respiratory metabolism in both strains and independent of the carbon source. Only minor differences were observed in the flux distributions of the wild type and cre1 deletion strain. Furthermore, the induction of the hydrolytic gene expression did not show altered flux distributions and did not affect the relative amino acid requirements or relative anabolic

  16. Atmospheric black carbon and warming effects influenced by the source and absorption enhancement in Central Europe

    Directory of Open Access Journals (Sweden)

    S. Nordmann

    2014-06-01

    Full Text Available Particles containing black carbon (BC, a strong absorbing substance, exert a rather uncertain direct and indirect radiative forcing in the atmosphere. To investigate the mass concentration and absorption properties of BC particles over Central Europe, the model WRF-Chem was used at a resolution of 12 km in conjunction with a high resolution BC emission inventory (EUCAARI 42-Pan-European Carbonaceous Aerosol Inventory; 1/8° × 1/16°. The model simulation was evaluated using measurements of equivalent soot carbon, absorption coefficients and particle number concentrations at 7 sites within the German Ultrafine Aerosol Network, PM10 mass concentrations from the dense measurement network of the German Federal Environmental Agency at 392 monitoring stations, and aerosol optical depth from MODIS and AERONET. A distinct time period (25 March to 10 April 2009 was chosen, during which the clean marine air mass prevailed in the first week and afterwards the polluted continental air mass mainly from south-east dominated with elevated daily average BC concentration up to 4 μg m−3. The simulated PM10 mass concentration, aerosol number concentration and optical depth were in a good agreement with the observations, while the modelled BC mass concentrations were found to be a factor of 2 lower than the observations. Together with backtrajectories, detailed model bias analyses suggested that the current BC emission in countries to the east and south of Germany might be underestimated by a factor of 5, at least for the simulation period. Running the model with upscaled BC emissions in these regions led to a smaller model bias and a better correlation between model and measurement. On the contrary, the particle absorption coefficient was positively biased by about 20% even when the BC mass concentration was underestimated by around 50%. This indicates that the internal mixture treatment of BC in the WRF-Chem optical calculation is unrealistic in our case

  17. Modeling the diversion of primary carbon flux into secondary metabolism under variable nitrate and light/dark conditions.

    Science.gov (United States)

    Larbat, Romain; Robin, Christophe; Lillo, Cathrine; Drengstig, Tormod; Ruoff, Peter

    2016-08-01

    In plants, the partitioning of carbon resources between growth and defense is detrimental for their development. From a metabolic viewpoint, growth is mainly related to primary metabolism including protein, amino acid and lipid synthesis, whereas defense is based notably on the biosynthesis of a myriad of secondary metabolites. Environmental factors, such as nitrate fertilization, impact the partitioning of carbon resources between growth and defense. Indeed, experimental data showed that a shortage in the nitrate fertilization resulted in a reduction of the plant growth, whereas some secondary metabolites involved in plant defense, such as phenolic compounds, accumulated. Interestingly, sucrose, a key molecule involved in the transport and partitioning of carbon resources, appeared to be under homeostatic control. Based on the inflow/outflow properties of sucrose homeostatic regulation we propose a global model on how the diversion of the primary carbon flux into the secondary phenolic pathways occurs at low nitrate concentrations. The model can account for the accumulation of starch during the light phase and the sucrose remobilization by starch degradation during the night. Day-length sensing mechanisms for variable light-dark regimes are discussed, showing that growth is proportional to the length of the light phase. The model can describe the complete starch consumption during the night for plants adapted to a certain light/dark regime when grown on sufficient nitrate and can account for an increased accumulation of starch observed under nitrate limitation.

  18. Phenotyping hepatocellular metabolism using uniformly labeled carbon-13 molecular probes and LC-HRMS stable isotope tracing.

    Science.gov (United States)

    Meissen, John K; Pirman, David A; Wan, Min; Miller, Emily; Jatkar, Aditi; Miller, Russell; Steenwyk, Rick C; Blatnik, Matthew

    2016-09-01

    Metabolite stable isotope tracing is a powerful bioanalytical strategy that has the potential to unravel phenotypic markers of early pharmaceutical efficacy by monitoring enzymatic incorporation of carbon-13 atoms into targeted pathways over time. The practice of probing biological systems with carbon-13 labeled molecules using broad MS-based screens has been utilized for many years in academic laboratories but has had limited application in the pharmaceutical R&D environment. The goal of this work was to establish a LCMS analytical workflow that was capable of monitoring carbon-13 isotope changes in glycolysis, the TCA and urea cycles, and non-essential amino acid metabolism. This work applies a standardized protein precipitation with 80% cold methanol and two distinct reverse-phase ion-pair liquid chromatography methods coupled to either a positive- or negative-ion mode high-resolution accurate mass spectrometry screening method. The data herein combines thousands of single-point peak integrations into a novel metabolite network map as a visualization aid to probe and monitor stable isotope incorporation in murine hepatocytes using uniformly labeled (13)C6 glucose, (13)C3 lactate, and (13)C5 glutamine. This work also demonstrates that nitrogen metabolism may have a large influence on the TCA cycle and gluconeogenic carbon fluxes in hepatocyte cell culture. PMID:27343766

  19. Central metabolism in Mycobacterium smegmatis during the transition from O2-rich to O2-poor conditions as studied by isotopomer-assisted metabolite analysis.

    Science.gov (United States)

    Tang, Yinjie J; Shui, Wenqing; Myers, Samuel; Feng, Xueyang; Bertozzi, Carolyn; Keasling, Jay D

    2009-08-01

    Isotopomer-assisted metabolite analysis was used to investigate the central metabolism of Mycobacterium smegmatis and its transition from normal growth to a non-replicating state under a hypoxic environment. Tween 80 significantly promoted aerobic growth by improving O(2) transfer, while only small amount was degraded and metabolized via the TCA cycle for biomass synthesis. As the bacillus encountered hypoxic stress, isotopomer analysis suggested: (1) isocitrate lyase activity increased, which further induced glyoxylate pathway and glycine dehydrogenase for replenishing NAD(+); (2) the relative amount of acetyl-CoA entering the TCA cycle was doubled, whereas little entered the glycolytic and pentose phosphate pathways. PMID:19357814

  20. Carbonate cementation-dissolution in deep-seated sandstones near the overpressure top in central Junggar Basin, Xinjiang, NW China

    Institute of Scientific and Technical Information of China (English)

    YANG Zhi; HE Sheng; WANG Furong; HE Zhiliang; WU Hengzhi; MENG Xianlong

    2009-01-01

    Fluid/rock interaction occurs frequently in the sandstones near the overpressure top in central Junggar Basin, and carbonate cementation-dissolution is related closely to the formation of secondary pores in the reservoir sandstones. From petrological, hydrochemical and fluid-inclusion studies of the deep-seated sandstones near the overpressure top in central Junggar Basin and the carbon and oxygen isotopic characteristics of carbonate cements in those sandstones, the following conclusions can be drawn: (1) Carbonates are the major cements. Two-stage cemen-tation was commonly developed, with late-stage ferroan carbonate cementation being dominant; several secondary porosity zones were developed vertically in the sandstones near the overpressure top, and there is a mutually com-pensatory relationship between the carbonate contents and the mean porosity; (2) the alkalescent formation-water chemical environments are in favor of carbonate precipitation; (3) there were two phases of thermal fluid activity which are related to the late-stage carbonate cementation-dissolution; (4) with the overpressure top as the boundary, carbonate cements in the sandstones have slightly negative δ13C and δ180 values, showing such a variation trend that the δ13C and δ18O values near the coal-bearing Jurassic strata are lighter, those in the overpressure top are heavier, and those at the upper part of the overpressure top are lighter, which is considered to be the result of kinetic isotope fractionation driven by episodically overpressured fluid flow; (5) carbonate cementation is closely associated with the decarboxylation of organic acids, and secondary porosity zones resultant from dissolution by organic acids and CO2 derived from Jurassic coal-beating strata, are the most important reservoir space of hydrocarbon, Studies of the mechanisms of carbonate cementation-dissolution and formation of secondary pores in the deep-seated sandstones near the overpressure top are of great

  1. Spatial variability of soil carbon stock in the Urucu river basin, Central Amazon-Brazil.

    Science.gov (United States)

    Ceddia, Marcos Bacis; Villela, André Luis Oliveira; Pinheiro, Érika Flávia Machado; Wendroth, Ole

    2015-09-01

    The Amazon Forest plays a major role in C sequestration and release. However, few regional estimates of soil organic carbon (SOC) stock in this ecoregion exist. One of the barriers to improve SOC estimates is the lack of recent soil data at high spatial resolution, which hampers the application of new methods for mapping SOC stock. The aims of this work were: (i) to quantify SOC stock under undisturbed vegetation for the 0-30 and the 0-100 cm under Amazon Forest; (ii) to correlate the SOC stock with soil mapping units and relief attributes and (iii) to evaluate three geostatistical techniques to generate maps of SOC stock (ordinary, isotopic and heterotopic cokriging). The study site is located in the Central region of Amazon State, Brazil. The soil survey covered the study site that has an area of 80 km(2) and resulted in a 1:10,000 soil map. It consisted of 315 field observations (96 complete soil profiles and 219 boreholes). SOC stock was calculated by summing C stocks by horizon, determined as a product of BD, SOC and the horizon thickness. For each one of the 315 soil observations, relief attributes were derived from a topographic map to understand SOC dynamics. The SOC stocks across 30 and 100 cm soil depth were 3.28 and 7.32 kg C m(-2), respectively, which is, 34 and 16%, lower than other studies. The SOC stock is higher in soils developed in relief forms exhibiting well-drained soils, which are covered by Upland Dense Tropical Rainforest. Only SOC stock in the upper 100 cm exhibited spatial dependence allowing the generation of spatial variability maps based on spatial (co)-regionalization. The CTI was inversely correlated with SOC stock and was the only auxiliary variable feasible to be used in cokriging interpolation. The heterotopic cokriging presented the best performance for mapping SOC stock.

  2. Metabolic bone disease and central retinal degeneration in a kitten due to nutritional inadequacy of an all-meat raw diet

    Directory of Open Access Journals (Sweden)

    Catherine Lenox

    2015-05-01

    Full Text Available A 5-month-old castrated male Sphynx kitten presented with left hindlimb lameness shortly after adoption. Prior to adoption, the breeder had fed the kitten an exclusively raw chicken diet. Radiographs revealed generalized osteopenia and a left tibia–fibula fracture. Ophthalmic examination revealed corneal vascularization and opacity in the right eye, and lesions suggestive of feline central retinal degeneration in the left eye. The patient’s diagnoses included metabolic bone disease and feline central retinal degeneration, which can result from taurine deficiency. The kitten’s nutritional diseases were managed with a complete and balanced canned diet designed for kitten growth and with taurine supplementation.

  3. Systematically variable planktonic carbon metabolism along a land-to-lake gradient in a Great Lakes coastal zone

    Science.gov (United States)

    Weinke, Anthony D.; Kendall, Scott T.; Kroll, Daniel J.; Strickler, Eric A.; Weinert, Maggie E.; Holcomb, Thomas M.; Defore, Angela A.; Dila, Deborah K.; Snider, Michael J.; Gereaux, Leon C.; Biddanda, Bopaiah A.

    2014-01-01

    During the summers of 2002–2013, we measured rates of carbon metabolism in surface waters of six sites across a land-to-lake gradient from the upstream end of drowned river-mouth Muskegon Lake (ML) (freshwater estuary) to 19 km offshore in Lake Michigan (LM) (a Great Lake). Despite considerable inter-year variability, the average rates of gross production (GP), respiration (R) and net production (NP) across ML (604 ± 58, 222 ± 22 and 381 ± 52 µg C L−1 day−1, respectively) decreased steeply in the furthest offshore LM site (22 ± 3, 55 ± 17 and −33 ± 15 µg C L−1day−1, respectively). Along this land-to-lake gradient, GP decreased by 96 ± 1%, whereas R only decreased by 75 ± 9%, variably influencing the carbon balance along this coastal zone. All ML sites were consistently net autotrophic (mean GP:R = 2.7), while the furthest offshore LM site was net heterotrophic (mean GP:R = 0.4). Our study suggests that pelagic waters of this Great Lakes coastal estuary are net carbon sinks that transition into net carbon sources offshore. Reactive and dynamic estuarine coastal zones everywhere may contribute similarly to regional and global carbon cycles. PMID:25954055

  4. Spatial variability of soil carbon stock in the Urucu river basin, Central Amazon-Brazil

    International Nuclear Information System (INIS)

    The Amazon Forest plays a major role in C sequestration and release. However, few regional estimates of soil organic carbon (SOC) stock in this ecoregion exist. One of the barriers to improve SOC estimates is the lack of recent soil data at high spatial resolution, which hampers the application of new methods for mapping SOC stock. The aims of this work were: (i) to quantify SOC stock under undisturbed vegetation for the 0–30 and the 0–100 cm under Amazon Forest; (ii) to correlate the SOC stock with soil mapping units and relief attributes and (iii) to evaluate three geostatistical techniques to generate maps of SOC stock (ordinary, isotopic and heterotopic cokriging). The study site is located in the Central region of Amazon State, Brazil. The soil survey covered the study site that has an area of 80 km2 and resulted in a 1:10,000 soil map. It consisted of 315 field observations (96 complete soil profiles and 219 boreholes). SOC stock was calculated by summing C stocks by horizon, determined as a product of BD, SOC and the horizon thickness. For each one of the 315 soil observations, relief attributes were derived from a topographic map to understand SOC dynamics. The SOC stocks across 30 and 100 cm soil depth were 3.28 and 7.32 kg C m−2, respectively, which is, 34 and 16%, lower than other studies. The SOC stock is higher in soils developed in relief forms exhibiting well-drained soils, which are covered by Upland Dense Tropical Rainforest. Only SOC stock in the upper 100 cm exhibited spatial dependence allowing the generation of spatial variability maps based on spatial (co)-regionalization. The CTI was inversely correlated with SOC stock and was the only auxiliary variable feasible to be used in cokriging interpolation. The heterotopic cokriging presented the best performance for mapping SOC stock. - Highlights: • The SOC stocks across 30 and 100 cm depth were 3.28 and 7.32 kg C m−2, respectively. • SOC stocks were 34 and 16%, respectively, lower

  5. Spatial variability of soil carbon stock in the Urucu river basin, Central Amazon-Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Ceddia, Marcos Bacis, E-mail: marcosceddia@gmail.com [Department of Soil, Institute of Agronomy, Universidade Federal Rural do Rio de Janeiro (UFRRJ), Seropédica, RJ 23890-000 (Brazil); Villela, André Luis Oliveira [Colégio Técnico da UFRRJ, RJ, Seropédica 23890-000 (Brazil); Pinheiro, Érika Flávia Machado [Department of Soil, Institute of Agronomy, Universidade Federal Rural do Rio de Janeiro (UFRRJ), Seropédica, RJ 23890-000 (Brazil); Wendroth, Ole [Department of Plant & Soil Sciences, University of Kentucky, College of Agriculture, Lexington, KY (United States)

    2015-09-01

    The Amazon Forest plays a major role in C sequestration and release. However, few regional estimates of soil organic carbon (SOC) stock in this ecoregion exist. One of the barriers to improve SOC estimates is the lack of recent soil data at high spatial resolution, which hampers the application of new methods for mapping SOC stock. The aims of this work were: (i) to quantify SOC stock under undisturbed vegetation for the 0–30 and the 0–100 cm under Amazon Forest; (ii) to correlate the SOC stock with soil mapping units and relief attributes and (iii) to evaluate three geostatistical techniques to generate maps of SOC stock (ordinary, isotopic and heterotopic cokriging). The study site is located in the Central region of Amazon State, Brazil. The soil survey covered the study site that has an area of 80 km{sup 2} and resulted in a 1:10,000 soil map. It consisted of 315 field observations (96 complete soil profiles and 219 boreholes). SOC stock was calculated by summing C stocks by horizon, determined as a product of BD, SOC and the horizon thickness. For each one of the 315 soil observations, relief attributes were derived from a topographic map to understand SOC dynamics. The SOC stocks across 30 and 100 cm soil depth were 3.28 and 7.32 kg C m{sup −2}, respectively, which is, 34 and 16%, lower than other studies. The SOC stock is higher in soils developed in relief forms exhibiting well-drained soils, which are covered by Upland Dense Tropical Rainforest. Only SOC stock in the upper 100 cm exhibited spatial dependence allowing the generation of spatial variability maps based on spatial (co)-regionalization. The CTI was inversely correlated with SOC stock and was the only auxiliary variable feasible to be used in cokriging interpolation. The heterotopic cokriging presented the best performance for mapping SOC stock. - Highlights: • The SOC stocks across 30 and 100 cm depth were 3.28 and 7.32 kg C m{sup −2}, respectively. • SOC stocks were 34 and 16

  6. Endothelial dysfunction in normal and prediabetic rats with metabolic syndrome exposed by oral gavage to carbon black nanoparticles

    DEFF Research Database (Denmark)

    Folkmann, Janne Kjærsgaard; Vesterdal, Lise Kristine; Sheykhzade, Majid;

    2012-01-01

    Exposure to nanosized particles may increase the risk of cardiovascular diseases by endothelial dysfunction, particularly in susceptible subjects with metabolic syndrome. We investigated vasomotor dysfunction in aorta from obese and lean Zucker rats after oral exposure to nanosized carbon black (CB......-induced vasorelaxation and phenylephrine-induced vasocontraction was not affected in rats exposed to CB. The endothelial dysfunction was not observed in rats sacrificed 13 weeks after the last CB exposure. There was unaltered expression of Chrm3, Nos3, Nos2, Ccl2, and Hmox1 in aorta tissue of CB-exposed rats. In...... conclusion, repeated oral exposure to CB was associated with endothelial dysfunction in rats, further aggravating the effect of metabolic syndrome....

  7. Inter-Strain Differences in Liver Injury and One-Carbon Metabolism in Alcohol-Fed Mice

    Science.gov (United States)

    Tsuchiya, Masato; Ji, Cheng; Kosyk, Oksana; Shymonyak, Svitlana; Melnyk, Stepan; Kono, Hiroshi; Tryndyak, Volodymyr; Muskhelishvili, Levan; Pogribny, Igor P.; Kaplowitz, Neil; Rusyn, Ivan

    2012-01-01

    Alcoholic liver injury is a major public health issue worldwide. Even though the major mechanisms of this disease have been established over the past decades, little is known about genetic susceptibility factors that may predispose individuals who abuse alcoholic beverages to liver damage and subsequent pathological conditions. We hypothesized that a panel of genetically diverse mouse strains may be used to examine the role of ER stress and one-carbon metabolism in the mechanism of inter-individual variability in alcoholic liver injury. We administered alcohol (up to 27 mg/kg/d) in high fat diet using intragastric intubation model for 28 days to male mice from 14 inbred strains (129S1/SvImJ, AKR/J, BALB/cJ, BALB/cByJ, BTBR T+tf/J, C3H/HeJ, C57BL/10J, DBA/2J, FVB/NJ, KK/HIJ, MOLF/EiJ, NZW/LacJ, PWD/PhJ, and WSB/EiJ). Profound inter-strain differences (more than 3-fold) in alcohol-induced steatohepatitis were observed among the strains in spite of consistently high levels of urine alcohol that was monitored throughout the study. We found that endoplasmic reticulum stress genes were induced only in strains with the highest liver injury. Liver glutathione and methyl donor levels were affected in all strains, albeit to a different degree. Most pronounced effects that were closely associated with the degree of liver injury were hyperhomocysteinemia and strain-dependent differences in expression patterns of one-carbon metabolism-related genes. Conclusion Our data demonstrate that strain differences in alcohol-induced liver injury and steatosis are striking and independent of alcohol exposure and the most severely affected strains exhibit major differences in the expression of ER stress markers and genes of one-carbon metabolism. PMID:22307928

  8. Remodeling of central metabolism in invasive breast cancer compared to normal breast tissue – a GC-TOFMS based metabolomics study

    Directory of Open Access Journals (Sweden)

    Budczies Jan

    2012-07-01

    Full Text Available Abstract Background Changes in energy metabolism of the cells are common to many kinds of tumors and are considered a hallmark of cancer. Gas chromatography followed by time-of-flight mass spectrometry (GC-TOFMS is a well-suited technique to investigate the small molecules in the central metabolic pathways. However, the metabolic changes between invasive carcinoma and normal breast tissues were not investigated in a large cohort of breast cancer samples so far. Results A cohort of 271 breast cancer and 98 normal tissue samples was investigated using GC-TOFMS-based metabolomics. A total number of 468 metabolite peaks could be detected; out of these 368 (79% were significantly changed between cancer and normal tissues (p80%. Two-metabolite classifiers, constructed as ratios of the tumor and normal tissues markers, separated cancer from normal tissues with high sensitivity and specificity. Specifically, the cytidine-5-monophosphate / pentadecanoic acid metabolic ratio was the most significant discriminator between cancer and normal tissues and allowed detection of cancer with a sensitivity of 94.8% and a specificity of 93.9%. Conclusions For the first time, a comprehensive metabolic map of breast cancer was constructed by GC-TOF analysis of a large cohort of breast cancer and normal tissues. Furthermore, our results demonstrate that spectrometry-based approaches have the potential to contribute to the analysis of biopsies or clinical tissue samples complementary to histopathology.

  9. Early differentiation in biomass production and carbon sequestration of white poplar and its two hybrids in Central Iran

    Institute of Scientific and Technical Information of China (English)

    Hormoz Sohrabi; Mohammad Kazem Parsapour; Ali Soltani; Yaghoub Iranmanesh

    2015-01-01

    We assessed the potential of white poplar (Populus alba L.) and its inter-sectional hybridization with euphrates poplar (P. euphratica Oliv.) for carbon storage and sequestration in central Iran. Trials were established at planting density of 2,500 trees per hectare in block ran-domized design with three replicates. After 6 years, we measured the above-ground biomass of tree components (trunk, branch, bark, twig and leaf), and assessed soil carbon at three depths. P. alba × euphratica plantation stored significantly more carbon (22.3 t ha-1) than P. alba (16.7 t ha-1) and P. euphratica × alba (13.1 t ha-1). Most of the carbon was accumulated in the above-ground biomass (61.1%in P. alba, 72.4%in P. alba × euphra-tica and 56.0% in P. euphratica × alba). There was no significant difference in soil carbon storage. Also, biomass allocation was different between white poplar P. alba and its inter-sectional hybridization. Therefore, there was a yield difference due to genomic imprinting, which increased the possibility that paternally and maternally inherited wood production alleles would be differentially expressed in the new crossing.

  10. Single nucleotide polymorphisms of one-carbon metabolism and cancers of the esophagus, stomach, and liver in a Chinese population.

    Directory of Open Access Journals (Sweden)

    Shen-Chih Chang

    Full Text Available One-carbon metabolism (folate metabolism is considered important in carcinogenesis because of its involvement in DNA synthesis and biological methylation reactions. We investigated the associations of single nucleotide polymorphisms (SNPs in folate metabolic pathway and the risk of three GI cancers in a population-based case-control study in Taixing City, China, with 218 esophageal cancer cases, 206 stomach cancer cases, 204 liver cancer cases, and 415 healthy population controls. Study participants were interviewed with a standardized questionnaire, and blood samples were collected after the interviews. We genotyped SNPs of the MTHFR, MTR, MTRR, DNMT1, and ALDH2 genes, using PCR-RFLP, SNPlex, or TaqMan assays. To account for multiple comparisons and reduce the chances of false reports, we employed semi-Bayes (SB shrinkage analysis. After shrinkage and adjusting for potential confounding factors, we found positive associations between MTHFR rs1801133 and stomach cancer (any T versus C/C, SB odds-ratio [SBOR]: 1.79, 95% posterior limits: 1.18, 2.71 and liver cancer (SBOR: 1.51, 95% posterior limits: 0.98, 2.32. There was an inverse association between DNMT1 rs2228612 and esophageal cancer (any G versus A/A, SBOR: 0.60, 95% posterior limits: 0.39, 0.94. In addition, we detected potential heterogeneity across alcohol drinking status for ORs relating MTRR rs1801394 to esophageal (posterior homogeneity P = 0.005 and stomach cancer (posterior homogeneity P = 0.004, and ORs relating MTR rs1805087 to liver cancer (posterior homogeneity P = 0.021. Among non-alcohol drinkers, the variant allele (allele G of these two SNPs was inversely associated with the risk of these cancers; while a positive association was observed among ever-alcohol drinkers. Our results suggest that genetic polymorphisms related to one-carbon metabolism may be associated with cancers of the esophagus, stomach, and liver. Heterogeneity across alcohol consumption status of

  11. Using a genome-scale metabolic model of Enterococcus faecalis V583 to assess amino acid uptake and its impact on central metabolism

    NARCIS (Netherlands)

    N. Veith; M. Solheim; K.W.A. van Grinsven; B.G. Olivier; J. Levering; R. Grosseholz; J. Hugenholtz; H. Holo; I. Nes; B. Teusink; U. Kummer

    2015-01-01

    Increasing antibiotic resistance in pathogenic bacteria necessitates the development of new medication strategies. Interfering with the metabolic network of the pathogen can provide novel drug targets but simultaneously requires a deeper and more detailed organism-specific understanding of the metab

  12. Metabolic responses to the acute ingestion of two commercially available carbonated beverages: A pilot study

    OpenAIRE

    Mendel Ron W; Hofheins Jennifer E

    2007-01-01

    Abstract Background The purpose of this placebo-controlled, double-blind cross-over study was to compare the effects of two commercially available soft drinks on metabolic rate. Methods After giving informed consent, twenty healthy men and women were randomly assigned to ingest 12 ounces of Celsius™ and, on a separate day, 12 ounces of Diet Coke®. All subjects completed both trials using a randomized, counterbalanced design. Metabolic rate (via indirect calorimetry) and substrate oxidation (v...

  13. Microbial community structure and functional metabolic diversity are associated with organic carbon availability in an agricultural soil

    Institute of Scientific and Technical Information of China (English)

    LI Juan; LI Yan-ting; YANG Xiang-dong; ZHANG Jian-jun; LIN Zhi-an; ZHAO Bing-qiang

    2015-01-01

    Exploration of soil environmental characteristics governing soil microbial community structure and activity may improve our understanding of biogeochemical processes and soil quality. The impact of soil environmental characteristics especialy organic carbon availability after 15-yr different organic and inorganic fertilizer inputs on soil bacterial community structure and functional metabolic diversity of soil microbial communities were evaluated in a 15-yr fertilizer experiment in Chang-ping County, Beijing, China. The experiment was a wheat-maize rotation system which was established in 1991 including four different fertilizer treatments. These treatments included: a non-amended control (CK), a commonly used application rate of inorganic fertilizer treatment (NPK); a commonly used application rate of inorganic fertilizer with swine manure in-corporated treatment (NPKM), and a commonly used application rate of inorganic fertilizer with maize straw incorporated treatment (NPKS). Denaturing gradient gel electrophoresis (DGGE) of the 16S rRNA gene was used to determine the bacterial community structure and single carbon source utilization proifles were determined to characterize the microbial community functional metabolic diversity of different fertilizer treatments using Biolog Eco plates. The results indicated that long-term fertilized treatments signiifcantly increased soil bacterial community structure compared to CK. The use of inorganic fertilizer with organic amendments incorporated for long term (NPKM, NPKS) signiifcantly promoted soil bacterial structure than the application of inorganic fertilizer only (NPK), and NPKM treatment was the most important driver for in-creases in the soil microbial community richness (S) and structural diversity (H). Overal utilization of carbon sources by soil microbial communities (average wel color development, AWCD) and microbial substrate utilization diversity and evenness indices (H’ and E) indicated that long

  14. The central and eastern Arabian Sea as a perennial source of atmospheric carbon dioxide

    Digital Repository Service at National Institute of Oceanography (India)

    Sarma, V.V.S.S.; DileepKumar, M.; George, M.D.

    Seasonal (winter monsoon, intermonsoon and southwest monsoon) and interannual (between southwest monsoon seasons of 1995 and 1996) variations in total carbon dioxide (TCO sub(2)) and partial pressure of CO sub(2) (pCO sub(2)) were studied...

  15. Comparative genome analysis of central nitrogen metabolism and its control by GlnR in the class Bacilli

    NARCIS (Netherlands)

    Groot Kormelink, T.; Koenders, E.; Hagemeijer, Y.; Overmars, L.; Siezen, R.J.; De Vos, W.M.; Francke, C.

    2012-01-01

    Background: The assimilation of nitrogen in bacteria is achieved through only a few metabolic conversions between alpha-ketoglutarate, glutamate and glutamine. The enzymes that catalyze these conversions are glutamine synthetase, glutaminase, glutamate dehydrogenase and glutamine alpha-ketoglutarate

  16. Comparative genome analysis of central nitrogen metabolism and its control by GlnR in the class Bacilli.

    NARCIS (Netherlands)

    Groot Kormelink, T.; Koenders, E.; Hagemeijer, Y.; Overmars, L.; Siezen, R.J.; Vos, W.M. de; Francke, C.

    2012-01-01

    ABSTRACT: BACKGROUND: The assimilation of nitrogen in bacteria is achieved through only a few metabolic conversions between alpha-ketoglutarate, glutamate and glutamine. The enzymes that catalyze these conversions are glutamine synthetase, glutaminase, glutamate dehydrogenase and glutamine alpha-ket

  17. Comparative genome analysis of central nitrogen metabolism and its control by GlnR in the class Bacilli

    NARCIS (Netherlands)

    Kormelink, T.G.; Koenders, E.; Hagemeijer, Y.; Overmars, L.; Siezen, R.J.; Vos, de W.M.; Francke, C.

    2012-01-01

    BACKGROUND: The assimilation of nitrogen in bacteria is achieved through only a few metabolic conversions between alpha-ketoglutarate, glutamate and glutamine. The enzymes that catalyze these conversions are glutamine synthetase, glutaminase, glutamate dehydrogenase and glutamine alpha-ketoglutarate

  18. Field Demonstration of Carbon Dioxide Miscible Flooding in the Lansing-Kansas City Formation, Central Kansas

    Energy Technology Data Exchange (ETDEWEB)

    Alan Byrnes; G. Paul Willhite; Don Green; Richard Pancake; JyunSyung Tsau; W. Lynn Watney; John Doveton; Willard Guy; Rodney Reynolds; Dave Murfin; James Daniels; Russell Martin; William Flanders; Dave Vander Griend; Eric Mork; Paul Cantrell

    2010-03-07

    A pilot carbon dioxide miscible flood was initiated in the Lansing Kansas City C formation in the Hall Gurney Field, Russell County, Kansas. The reservoir zone is an oomoldic carbonate located at a depth of about 2900 feet. The pilot consists of one carbon dioxide injection well and three production wells. Continuous carbon dioxide injection began on December 2, 2003. By the end of June 2005, 16.19 MM lb of carbon dioxide was injected into the pilot area. Injection was converted to water on June 21, 2005 to reduce operating costs to a breakeven level with the expectation that sufficient carbon dioxide was injected to displace the oil bank to the production wells by water injection. By March 7,2010, 8,736 bbl of oil were produced from the pilot. Production from wells to the northwest of the pilot region indicates that oil displaced from carbon dioxide injection was produced from Colliver A7, Colliver A3, Colliver A14 and Graham A4 located on adjacent leases. About 19,166 bbl of incremental oil were estimated to have been produced from these wells as of March 7, 2010. There is evidence of a directional permeability trend toward the NW through the pilot region. The majority of the injected carbon dioxide remains in the pilot region, which has been maintained at a pressure at or above the minimum miscibility pressure. Estimated oil recovery attributed to the CO2 flood is 27,902 bbl which is equivalent to a gross CO2 utilization of 4.8 MCF/bbl. The pilot project is not economic.

  19. δ13C chemostratigraphy in the upper Tremadocian through lower Katian (Ordovician carbonate succession of the Siljan district, central Sweden

    Directory of Open Access Journals (Sweden)

    Oliver Lehnert

    2014-12-01

    Full Text Available Based on δ13C data from two drillcores recovered from the Siljan district, we present a first continuous carbon isotope record of the upper Tremadocian–lower Katian limestone succession of central Sweden. New names for some isotopic carbon excursions from the Cambrian–Ordovician boundary through the basal Darriwilian are introduced. The Mora 001 core from the western part of the Siljan impact structure ranges through the Lower–Middle Ordovician, whereas the Solberga 1 core from its eastern part ranges through the Middle–lower Upper Ordovician. Upper Tremadocian and Floian units are extremely condensed and include extensive stratigraphic gaps. Multiple hardgrounds, sometimes with minor karstic overprint, imply recurrent periods of erosion and/or non-deposition. Like in other parts of Sweden, the Dapingian and Darriwilian succession is characterized by a relatively complete sedimentary record and low sedimentation rates.

  20. Land use change and carbon cycle in arid and semi-arid lands of East and Central Asia

    Institute of Scientific and Technical Information of China (English)

    Togtohyn; Chuluun; Dennis; Ojima

    2002-01-01

    Dramatic changes in land use have occurred in arid and semi-arid landsof Asia during the 20th century. Grassland conversion into croplands and ecosystem degradation is widespread due to the high growth rate of human population and political reforms of pastoral systems. Rangeland degradation made many parts of this region vulnerable to environmental and political changes. The collapse of the livestock sector in some states of central Asia, expansion of livestock inChina and intensive degradation of grasslands in China are examples of the responses of pastoral systems to these changes over the past decades. Carbon dynamics in this region is highly variable in space and time. Land use/cover changes with widespread reduction of forest and grasslands increased carbon emission from the region.

  1. Vegetation evolution on the central Chinese Loess Plateau since late Quaternary evidenced by elemental carbon isotopic composition

    Institute of Scientific and Technical Information of China (English)

    ZHOU Bin; SHEN ChengDe; ZHENG HongBo; ZHAO MeiXun; SUN YanMin

    2009-01-01

    There are many controversial issues in loess studies such as natural vegetation types on the Chinese Loess Plateau during the historical periods and the spatial and temporal evolution of C3/C4 plants.Elemental carbon isotopic composition (δ13Cec) in the loess section may offer new evidence for these problems. Elemental carbon (EC) is produced by incomplete combustion of vegetation, and its carbon isotopic composition has a very small difference from that of the formal vegetation, then δ13Cec can be used as a record to recover the changes of vegetation. Elemental carbon was extracted by applying the oxidation method from the loess-paleosol sequence in the central Chinese Loess Plateau, and its carbon isotope composition was analyzed by the isotope mass spectrometer. The results showed that the vegetation in this region was a mixed type of C3 and C4 plants, dominated with C3 plants in most of the time. Since late Quaternary, C3/C4 plants may not follow a simple glacial-interglacial cycle mode on the Chinese Loess Plateau, but showing fluctuations. C3 plants increased gradually in L4 period, and more C3 plants occurred during S3 period, and C4 plants increased again during L3-L2 periods, after that, C3plants dominated again during S1-S0 periods. During periods of paleosol development, C3 plants were abundant in S3 and S1, and there were more C4 plants in S2 and S0. During periods of loess sedimentation, there were more C3 plants in L4 and L1, and there were more C4 plants in L3 and L2. On the orbital timescale, the vegetation variations revealed by δ13Cec record are consistent with the results of pollen data and also similar to the results obtained by organic carbon isotopic composition since the last glacial period.

  2. Frozen in Time? Microbial strategies for survival and carbon metabolism over geologic time in a Pleistocene permafrost chronosequence

    Science.gov (United States)

    Mackelprang, R.; Douglas, T. A.; Waldrop, M. P.

    2014-12-01

    Permafrost soils have received tremendous interest due to their importance as a global carbon store with the potential to be thawed over the coming centuries. Instead of being 'frozen in time,' permafrost contains active microbes. Most metagenomic studies have focused on Holocene aged permafrost. Here, we target Pleistocene aged ice and carbon rich permafrost (Yedoma), which can differ in carbon content and stage of decay. Our aim was to understand how microbes in the permafrost transform organic matter over geologic time and to identify physiological and biochemical adaptations that enable long-term survival. We used next-generation sequencing to characterize microbial communities along a permafrost age gradient. Samples were collected from the Cold Regions Research and Engineering Laboratory (CRREL) Permafrost Tunnel near Fox, AK, which penetrates a hillside providing access to permafrost ranging in age from 12 to 40 kyr. DNA was extracted directly from unthawed samples. 16S rRNA amplicon (16S) and shotgun metagenome sequencing revealed significant age-driven differences. First, microbial diversity declines with permafrost age, likely due to long-term exposure to environmental stresses and a reduction in metabolic resources. Second, we observed taxonomic differences among ages, with an increasing abundance of Firmicutes (endospore-formers) in older samples, suggesting that dormancy is a common survival strategy in older permafrost. Ordination of 16S and metagenome data revealed age-based clustering. Genes differing significantly between age categories included those involved in lipopolysaccharide assembly, cold-response, and carbon processing. These data point to the physiological adaptations to long-term frozen conditions and to the metabolic processes utilized in ancient permafrost. In fact, a gene common in older samples is involved in cadaverine production, which could potentially explain the putrefied smell of Pleistocene aged permafrost. Coupled with soil

  3. Application of central composite design to optimize the amount of carbon source and prebiotics for Bifidobacterium bifidum BB01

    Directory of Open Access Journals (Sweden)

    Shu Guowei

    2016-06-01

    Full Text Available The objective of the present study was to obtain the optimum proportion of the carbon source and prebiotics for Bifidobacterium bifidum BB01 by the central composite design (CCD. The effect of carbon source (lactose and two prebiotics (inulin and fructooligosaccharides on the BB01 were observed by measuring the OD600 value, pH value and the viable counts at 18h. The final optimized concentrations of carbon source and prebiotics were: lactose 1.6%, inulin 0.26%, and fructooligosaccharides 0.22%. The result indicates that the growth of B. bifidum BB01 shows an significant increase in the optimized culture medium (p < 0.05, the OD600 value reached 1.434 at 18h, which increased 6.58% compared to the control. And the viable counts of B. bifidum BB01 increased 24.36% and reached (2.17±0.06 ×109cfu/mL. The results show that the optimization of the carbon source and prebiotics using CCD in this study is workable and necessary.

  4. Carbon Emission from Forest Fires on Scots Pine Logging Sites in the Angara Region of Central Siberia

    Science.gov (United States)

    Ivanova, G. A.; Conard, S. G.; McRae, D. J.; Kukavskaya, E. A.; Bogorodskaya, A. V.; Kovaleva, N. M.

    2010-12-01

    Wildfire and large-scale forest harvesting are the two major disturbances in the Russian boreal forests. Non-recovered logged sites total about a million hectares in Siberia. Logged sites are characterized by higher fire hazard than forest sites due to the presence of generally untreated logging slash (i.e., available fuel) which dries out much more rapidly compared to understory fuels. Moreover, most logging sites can be easily accessed by local population; this increases the risk for fire ignition. Fire impacts on the overstory trees, subcanopy woody layer, and ground vegetation biomass were estimated on 14 logged and unlogged comparison sites in the Lower Angara Region in 2009-2010 as part of the NASA-funded NEESPI project, The Influence of Changing Forestry Practices on the Effects of Wildfire and on Interactions Between Fire and Changing Climate in Central Siberia. Based on calculated fuel consumption, we estimated carbon emission from fires on both logged and unlogged burned sites. Carbon emission from fires on logged sites appeared to be twice that on unlogged sites. Soil respiration decreased on both site types after fires. This reduction may partially offset fire-produced carbon emissions. Carbon emissions from fire and post-fire ecosystem damage on logged sites are expected to increase under changing climate conditions and as a result of anticipated increases in future forest harvesting in Siberia.

  5. Stable carbon isotope fractionation of trans-1,2-dichloroethylene during co-metabolic degradation by methanotrophic bacteria

    Science.gov (United States)

    Brungard, K.L.; Munakata-Marr, J.; Johnson, C.A.; Mandernack, K.W.

    2003-01-01

    Changes in the carbon isotope ratio (??13C) of trans-1,2-dichloroethylene (t-DCE) were measured during its co-metabolic degradation by Methylomonas methanica, a type I methanotroph, and Methylosinus trichosporium OB3b, a type II methanotroph. In closed-vessel incubation experiments with each bacterium, the residual t-DCE became progressively enriched in 13C, indicating isotopic fractionation. From these experiments, the biological fractionation during t-DCE co-metabolism, expressed as ??, was measured to be -3.5??? for the type I culture and -6.7??? for the type II culture. This fractionation effect and subsequent enrichment in the ??13C of the residual t-DCE can thus be applied to determine the extent of biodegradation of DCE by these organisms. Based on these results, isotopic fractionation clearly warrants further study, as measured changes in the ??13C values of chlorinated solvents could ultimately be used to monitor the extent of biodegradation in laboratory or field settings where co-metabolism by methanotrophs occurs. ?? 2002 Elsevier Science B.V. All rights reserved.

  6. Dissolved Pesticide and Organic Carbon Concentrations Detected in Surface Waters, Northern Central Valley, California, 2001-2002

    Science.gov (United States)

    Orlando, James L.; Jacobson, Lisa A.; Kuivila, Kathryn M.

    2004-01-01

    Field and laboratory studies were conducted to determine the effects of pesticide mixtures on Chinook salmon under various environmental conditions in surface waters of the northern Central Valley of California. This project was a collaborative effort between the U.S. Geological Survey (USGS) and the University of California. The project focused on understanding the environmental factors that influence the toxicity of pesticides to juvenile salmon and their prey. During the periods January through March 2001 and January through May 2002, water samples were collected at eight surface water sites in the northern Central Valley of California and analyzed by the USGS for dissolved pesticide and dissolved organic carbon concentrations. Water samples were also collected by the USGS at the same sites for aquatic toxicity testing by the Aquatic Toxicity Laboratory at the University of California Davis; however, presentation of the results of these toxicity tests is beyond the scope of this report. Samples were collected to characterize dissolved pesticide and dissolved organic carbon concentrations, and aquatic toxicity, associated with winter storm runoff concurrent with winter run Chinook salmon out-migration. Sites were selected that represented the primary habitat of juvenile Chinook salmon and included major tributaries within the Sacramento and San Joaquin River Basins and the Sacramento?San Joaquin Delta. Water samples were collected daily for a period of seven days during two winter storm events in each year. Additional samples were collected weekly during January through April or May in both years. Concentrations of 31 currently used pesticides were measured in filtered water samples using solid-phase extraction and gas chromatography-mass spectrometry at the U.S. Geological Survey's organic chemistry laboratory in Sacramento, California. Dissolved organic carbon concentrations were analyzed in filtered water samples using a Shimadzu TOC-5000A total organic carbon

  7. High-fat simple carbohydrate feeding impairs central and peripheral monoamine metabolic pathway triggering the onset of metabolic syndrome in C57Bl/6J mice

    Directory of Open Access Journals (Sweden)

    Serena S D'Souza

    2016-01-01

    Conclusion: HFSC diet impairs the central and peripheral dopaminergic and noradrenergic pathways in mice as evidenced by the disturbances in their hypothalamic, plasma, and urine levels and this might be one of the early factors contributing towards the development of the MetS.

  8. Metabolic Syndrome in Italian Obese Children and Adolescents: Stronger Association with Central Fat Depot than with Insulin Sensitivity and Birth Weight

    Directory of Open Access Journals (Sweden)

    Claudia Brufani

    2011-01-01

    Full Text Available Aim. To evaluate whether body fat distribution, birth weight, and family history for diabetes (FHD were associated with metabolic syndrome (MetS in children and adolescents. Methods. A total of 439 Italian obese children and adolescents (5–18 years were enrolled. Subjects were divided into 2 groups: prepubertal and pubertal. MetS was diagnosed according to the adapted National Cholesterol Education Program criteria. Birth weight percentile, central obesity index (measured by dual-energy X-ray absorptiometry, insulin sensitivity (ISI, and disposition index were evaluated. Multivariate logistic regression models were used to determine variables associated with MetS. Results. The prevalence of MetS was 17%, with higher percentage in adolescents than in children (21 versus 12%. In the overall population, central obesity index was a stronger predictor of MetS than insulin sensitivity and low birth weight. When the two groups were considered, central fat depot remained the strongest predictor of MetS, with ISI similarly influencing the probability of MetS in the two groups and birth weight being negatively associated to MetS only in pubertal individuals. Neither FHD nor degree of fatness was a significant predictor of MetS. Conclusion. Simple clinical parameters like increased abdominal adiposity and low birth weight could be useful tools to identify European obese adolescents at risk for metabolic complications.

  9. Preliminary Insights Into the Interplay Among Oxygen, Organic Carbon, and Microbial Metabolism in North Atlantic Subseafloor Sediment Communities

    Science.gov (United States)

    Amenabar, M. J.; Dore, J. E.; Spivack, A. J.; Murray, R. W.; D'Hondt, S.; Boyd, E. S.

    2015-12-01

    Deep marine sediments harbor abundant microbial cells that, if active, are likely to exert a strong influence on element biogeochemical cycling. However, our understanding of the fraction of cells that are active in situ and the metabolic processes that sustain them remain underexplored. Here we describe recent results of our studies aimed at unraveling the links between geochemical heterogeneity, cellular viability and synthesis, and metabolism along a vertical depth profile in sediment from four deep sites (>5 km beneath ocean surface) cored by R/V KNORR Expedition KN-223 in the North Atlantic (2014). These sediment columns exhibit varying levels of organic carbon and different vertical extents of oxygen (O2) penetration, which we hypothesize is due to variation in the extent of heterotrophic metabolism. We prepared most probable number (MPN) assays with acetate or peptone as electron donor and carbon source, and five different terminal electron acceptors (O2, NO3, SO4, MnO2, and ferrihydrite) with sediments from 4 to 5 depths in each of the four cores MPNs were similar for acetate- and peptone-amended cultures, regardless of electron acceptor, and generally decreased with depth in the sediment column. MPNs amended with O2 as electron acceptor were greater than MPNs amended with NO3, SO4, MnO2, and ferrihydrite in samples from all depths. Moreover, MPNs were higher for assays amended with O2 from cores where the depth of O2 penetration was shallow when compared to cores where O2 is predicted to penetrate to basement rock. These results are consistent with aerobic heterotrophs limiting the penetration of O2 in deep marine sediments, and thereby provide a mechanism to explain the relationship between low O2 penetrations in sediment cores with elevated organic carbon contents. We will also present results of our ongoing isotopic labeling experiments aimed at determining rates of DNA and protein synthesis as proxies for cell replication and productivity, respectively

  10. Talc-carbonate alteration of ultramafic rocks within the Leka Ophiolite Complex, Central Norway

    Science.gov (United States)

    Bjerga, A.; Konopásek, J.; Pedersen, R. B.

    2015-06-01

    Petrographic and geochemical analyses of partly and completely serpentinized and carbonated peridotites within the ultramafic section of the Leka Ophiolite Complex have been used to elucidate the evolution of alterations and identify possible fluid sources. The alterations show no evidence for any major deformation and are located along low-angle structures that were formed in a late stage of the structural evolution of the ophiolite complex. Modeling of mineral equilibria in the SiO2-MgO-FeO-Fe2O3-CaO-H2O ± CO2 system has been utilized to constrain the conditions during serpentinization and carbonation. The partly altered peridotites consist of the mineral assemblage olivine-clinopyroxene-serpentine-magnetite-brucite and formed at temperatures isotope values determined for dolomite from crosscutting carbonate lenses within the talc-carbonate rock yield δ13C values of ~- 5 indicative of a mantle source for the carbon required for the carbonation. Oxygen isotope values δSMOW18O of ~ 10.8-11.3‰ together with initial 87Sr/86Sri = 400Ma values of 0.7029 and 0.7063, suggest dehydration of rocks with mantle affinity as a source for the fluids. Based on analytical results and field observations we propose that the formation of the talc- and carbonate-bearing alteration zones is caused by the focused infiltration of fluids that originated at the bottom of already partly serpentinized ophiolite complex during extension-driven burial at the late stage of the Caledonian orogeny.

  11. Seagrass community metabolism: assessing the carbon sink capacity of seagrass meadows

    OpenAIRE

    Duarte, Carlos M.; Marbà, Núria; Gacia, Esperança; Fourqurean, James W.; Beggins, Jeff; Barrón, Cristina; Apostolaki, Eugenia T.

    2010-01-01

    The metabolic rates of seagrass communities were synthesized on the basis of a data set on seagrass community metabolism containing 403 individual estimates derived from a total of 155 different sites. Gross primary production (GPP) rates (mean ± SE = 224.9 ± 11.1 mmol O2 m−2 d−1) tended to be significantly higher than the corresponding respiration (R) rates (mean ± SE = 187.6 ± 10.1 mmol O2 m−2 d−1), indicating that seagrass meadows tend to be autotrophic ecosystems, reflected in a positive ...

  12. Stable Carbon Isotope Discrimination by Form IC Rubisco Enzymes of the Extremely Metabolically Versatile Rhodobacter sphaeroides and Ralstonia eutropha}

    Science.gov (United States)

    Thomas, P. J.; Boller, A. J.; Zhao, Z.; Tabita, F. R.; Cavanaugh, C. M.; Scott, K. M.

    2006-12-01

    Variations in the relative amounts of 12C and 13C in microbial biomass can be used to infer the pathway(s) autotrophs use to fix and assimilate dissolved inorganic carbon. Discrimination against 13C by the enzymes catalyzing autotrophic carbon fixation is a major factor dictating biomass stable carbon isotopic compositions (δ13C = {[13C/12Csample/13C/12Cstandard] - 1} × 1000). Five different forms of RubisCO (IA, IB, IC, ID, and II) are utilized by algae and autotrophic bacteria reliant on the Calvin-Benson cycle for carbon fixation. To date, isotope discrimination has been measured for form IA, IB, and II RubisCOs, and their ɛ values (={[12k/13k] - 1} × 1000; 12k and 13k = rates of 12C and 13C fixation) range from 18 to 29‰, explaining the variation in biomass δ13C values of autotrophs utilizing these enzymes. Isotope discrimination by form IC RubisCO has not been measured, despite the presence of this enzyme in many proteobacteria of ecological interest, including marine manganese-oxidizing bacteria, some nitrifying and nitrogen-fixing bacteria, and extremely metabolically versatile organisms such as Rhodobacter sphaeroides and Ralstonia eutropha. The purpose of this work was to determine the ɛ values for form IC RubisCO enzymes from R. sphaeroides and R. eutropha. Recombinant form IC RubisCOs were purified by conventional column chromatography procedures. Assay conditions (pH, dissolved inorganic carbon concentration) were tested to determine which parameters were conducive to the high rates of carbon fixation necessary for ɛ determination. Under standard conditions (pH 8.5 and 5 mM DIC), form IC RubisCO activities were sufficient for ɛ determination. Experiments are currently being conducted to measure the ɛ values of these enzymes. Sampling the full phylogenetic breadth of RubisCO enzymes for isotopic discrimination makes it possible to constrain the range of δ13C values of organisms fixing carbon via the Calvin-Benson cycle. These results are

  13. L-Lactic acid production from glycerol coupled with acetic acid metabolism by Enterococcus faecalis without carbon loss.

    Science.gov (United States)

    Murakami, Nao; Oba, Mana; Iwamoto, Mariko; Tashiro, Yukihiro; Noguchi, Takuya; Bonkohara, Kaori; Abdel-Rahman, Mohamed Ali; Zendo, Takeshi; Shimoda, Mitsuya; Sakai, Kenji; Sonomoto, Kenji

    2016-01-01

    Glycerol is a by-product in the biodiesel production process and considered as one of the prospective carbon sources for microbial fermentation including lactic acid fermentation, which has received considerable interest due to its potential application. Enterococcus faecalis isolated in our laboratory produced optically pure L-lactic acid from glycerol in the presence of acetic acid. Gas chromatography-mass spectrometry analysis using [1, 2-(13)C2] acetic acid proved that the E. faecalis strain QU 11 was capable of converting acetic acid to ethanol during lactic acid fermentation of glycerol. This indicated that strain QU 11 restored the redox balance by oxidizing excess NADH though acetic acid metabolism, during ethanol production, which resulted in lactic acid production from glycerol. The effects of pH control and substrate concentration on lactic acid fermentation were also investigated. Glycerol and acetic acid concentrations of 30 g/L and 10 g/L, respectively, were expected to be appropriate for lactic acid fermentation of glycerol by strain QU 11 at a pH of 6.5. Furthermore, fed-batch fermentation with 30 g/L glycerol and 10 g/L acetic acid wholly exhibited the best performance including lactic acid production (55.3 g/L), lactic acid yield (0.991 mol-lactic acid/mol-glycerol), total yield [1.08 mol-(lactic acid and ethanol)]/mol-(glycerol and acetic acid)], and total carbon yield [1.06 C-mol-(lactic acid and ethanol)/C-mol-(glycerol and acetic acid)] of lactic acid and ethanol. In summary, the strain QU 11 successfully produced lactic acid from glycerol with acetic acid metabolism, and an efficient fermentation system was established without carbon loss.

  14. Comparing CLM and CLM-ED as a basis for representing carbon cycling dynamics in a Central Amazonian forest

    Science.gov (United States)

    Knox, R. G.; Holm, J. A.; Koven, C. D.; Riley, W. J.; Chambers, J. Q.; Fisher, R.; Muszala, S.; Higuchi, N.

    2014-12-01

    Old-growth tropical forests are responsible for a potentially large portion of the terrestrial carbon sink, although the underlying control mechanisms of that sink, has large uncertainties. The quantification of the tropical forest carbon sink is a grand challenge of measurement scale. Therefore, there is a strong emphasis on incorporating improved vegetation structure and compositional representativeness in land-surface modeling. Vegetation demography, plant competition, mechanistic mortality, disturbance cycling, and plant functional traits strongly control carbon dynamics and energy budgets of the Earth's surface. Size and age structured scaling processes have not been represented in the widely used Community Land Model (CLM) until the recent inclusion of the Ecosystem Demography (ED) model into CLM 4.5, i.e., CLM-ED. The goal of this study was to compare how CLM-ED captured tropical carbon cycling dynamics compared to CLM and 16 years of field measurements from a central Amazonian forest. We evaluated critical carbon flux processes (Mg C ha-1 yr-1) such as net ecosystem exchange (NEE), net primary production (NPP), and autotrophic respiration (AR), and additional representations of growth and maintenance in CLM and CLM-ED. For a central Amazonian forest CLM estimated GPP from 2000-2012, with transient CO2 concentrations, to be 31.5 Mg C ha-1 yr-1 and was similar to field measurements, while initial evaluation of the newly developed CLM-ED estimated GPP to be substantially higher. The introduction of the size and age structure of ED to the CLM framework enables a finer granularity of state information in the canopy and new ways to represent canopy physics. Therefore alternative physics processes were compared, including those that are highly resolved at the cohort scale (i.e. plant groups) to those at the highly parameterized community scale (i.e. the plant canopy as a whole). CLM serves as the land-model component for nearly 40% of the Earth System Models

  15. Effect of carbon/nitrogen ratio on carbohydrate metabolism and light energy dissipation mechanisms in Arabidopsis thaliana.

    Science.gov (United States)

    Huarancca Reyes, Thais; Scartazza, Andrea; Lu, Yu; Yamaguchi, Junji; Guglielminetti, Lorenzo

    2016-08-01

    Carbon (C) and nitrogen (N) nutrient sources are essential elements for metabolism, and their availability must be tightly coordinated for the optimal growth and development in plants. Plants are able to sense and respond to different C/N conditions via specific partitioning of C and N sources and the regulation of a complex cellular metabolic activity. We studied how the interaction between C and N signaling could affect carbohydrate metabolism, soluble sugar levels, photochemical efficiency of photosystem II (PSII) and the ability to drive the excess energy in Arabidopsis seedlings under moderated and disrupted C/N-nutrient conditions. Invertase and sucrose synthase activities were markedly affected by C/N-nutrient status depending on the phosphorylation status, suggesting that these enzymes may necessarily be modulated by their direct phosphorylation or phosphorylation of proteins that form complex with them in response to C/N stress. In addition, the enzymatic activity of these enzymes was also correlated with the amount of sugars, which not only act as substrate but also as signaling compounds. Analysis of chlorophyll fluorescence in plants under disrupted C/N condition suggested a reduction of electron transport rate at PSII level associated with a higher capacity for non-radiative energy dissipation in comparison with plants under moderated C/N condition. In conclusion, the tight coordination between C and N not only affects the carbohydrates metabolism and their concentration within plant tissues, but also the partitioning of the excitation energy at PSII level between radiative (electron transport) and non-radiative (heat) dissipation pathways. PMID:27108206

  16. Carbon dioxide metabolism by Actinomyces viscosus: pathways for succinate and aspartate production.

    OpenAIRE

    Brown, A T; Breeding, L C

    1980-01-01

    14C-labeled bicarbonate was incorporated into trichloroacetic acid-insoluble material by cell suspensions of A. viscosus strain M100 and also into the four-carbon fermentation product, succinate, but not into the three-carbon fermentation product, lactate. The initial step in the conversion of 14C-labeled bicarbonate into both trichloroacetic acid-insoluble material and succinate was catalyzed by the enzyme phosphoenolypyruvate carboxylase, which served to convert the glycolytic intermediate,...

  17. Rodingitization and carbonization processes in Triassic ultramafic cumulates and lavas, Othris Mt, Central Greece

    Science.gov (United States)

    Koutsovitis, Petros; Magganas, Andreas; Economou, Georgios

    2016-04-01

    A Triassic magmatic sequence from the south Othris region is comprised of early stage basaltic pillow lavas, as well as late stage ultramafic rocks, lava flows, high-Mg doleritic dykes and pyroclastic tuffs. The ultramafic rocks include slightly serpentinized wehrlites and lavas consisting of cumulate olivine, variably textured clinopyroxene (cumulate, quench, hollow, skeletal or blade shaped), magnesiohornblende, tremolite, phlogopite, spinel, chlorite, garnet, serpentine, calcite and devitrified glass[1]. Part of their secondary mineralogy developed due to percolation of metasomatic fluids during rodingitization and carbonization processes. In ultramafic rocks from Agia Marina and Mili, rodingitization was rather penetratively and expressed with crystallization of hydrogarnets, accompanied by secondary diopside and chlorite. Hydrogarnets are characterized by their low Ti-contents (recycling thermal carbonated seawater, leached from the rifted Triassic platform carbonates. References. [1] Koutsovitis, Magganas, Ntaflos 2012: Lithos 144-145, 177-193; [2] Koutsovitis, Magganas, Pomonis, Ntaflos 2013: Lithos 172-173, 139-157.

  18. Carbon catabolite repression and global control of the carbohydrate metabolism in Lactococcus lactis.

    NARCIS (Netherlands)

    Luesink, E.J.

    1998-01-01

    In view of the economic importance of fermented dairy products considerable scientific attention has been given to various steps of fermentation processes, including the L-lactate formation of lactic acid bacteria (de Vos, 1996). In particular, the carbohydrate metabolism of L. lactis has been the s

  19. Characteristics of Gaseous Carbon Emission from a Tropical Peatland Fire: A Plot-Scale Field Experiment in Central Kalimantan, Indonesia

    Science.gov (United States)

    Hamada, Y.; Darung, U.; Limin, S. H.; Hatano, R.

    2014-12-01

    Tropical peatland in Southeast Asia is a vast reservoir of terrestrial carbon, which covers 24.8 million hectares and stores 68.5 PgC peat, equal to 11-14% of global peat carbon. In recent decades, large scale peatland fire has occurred frequently in that region, in which many areas of peatland were reclaimed with intention to use the land for forest plantation and rice paddy. We conducted a plot-scale peat burning experiment to elucidate the characteristics of gaseous carbon emission from a tropical peatland fire at the ground level. The experimental site was established at an open area 20 km southeast from Palangka Raya, Central Kalimantan Province, Indonesia. The size of the burning plot is 4 m in length and 3 m in width. Gas samples were collected at heights of 1.0, 0.5, 0.0 (aboveground), -0.1 and -0.2 m (belowground) through stainless steel and/or aluminum tubes settled across the edge of the plot. The concentrations of carbon dioxide (CO2), carbon monoxide (CO), methane (CH4) and particulate matter (PM) was determined. Soil temperature was recorded every 10 minutes 0.1 and 0.2 m below the ground surface. Twelve iron rods were installed in 1-m by 1-m square grid to determine the depth of burn scar. After ignition, flaming stage of peat burning was ceased within 1-2 hours. The following smoldering stage continued for a week. In the flaming stage, soil temperature at -0.1 m increased tentatively. After the smoldering stage began, the temperature rapidly increased to 350-450°C. Response of soil temperature at -0.2 m was less prominent. Concentrations of gaseous components became maximal in the flaming stage. During the smoldering stage, the concentrations gradually decreased. The influence of burning on CO2 and PM was prominently remained at -0.1 m, whereas those at -0.2 m were not so much. The averaged burnt depth was 5.8±5.1 cm. Based on bulk density of 0.22 g/cm3 and carbon content of 55.5%, the amount of carbon lost from the plot was 85.3 kg. Most of the

  20. Genome-wide meta-analysis of homocysteine and methionine metabolism identifies five one carbon metabolism loci and a novel association of ALDH1L1 with ischemic stroke

    Science.gov (United States)

    Circulating homocysteine levels (tHcy), a product of the folate one carbon metabolism pathway (FOCM) through the demethylation of methionine, are heritable and are associated with an increased risk of common diseases such as stroke, cardiovascular disease (CVD), cancer and dementia. The FOCM is the ...

  1. Simultaneous tracing of carbon and nitrogen isotopes in human cells.

    Science.gov (United States)

    Nilsson, Roland; Jain, Mohit

    2016-05-24

    Stable isotope tracing is a powerful method for interrogating metabolic enzyme activities across the metabolic network of living cells. However, most studies of mammalian cells have used (13)C-labeled tracers only and focused on reactions in central carbon metabolism. Cellular metabolism, however, involves other biologically important elements, including nitrogen, hydrogen, oxygen, phosphate and sulfur. Tracing stable isotopes of such elements may help shed light on poorly understood metabolic pathways. Here, we demonstrate the use of high-resolution mass spectrometry to simultaneously trace carbon and nitrogen metabolism in human cells cultured with (13)C- and (15)N-labeled glucose and glutamine. To facilitate interpretation of the complex isotopomer data generated, we extend current methods for metabolic flux analysis to handle multivariate mass isotopomer distributions (MMIDs). We find that observed MMIDs are broadly consistent with known biochemical pathways. Whereas measured (13)C MIDs were informative for central carbon metabolism, (15)N isotopes provided evidence for nitrogen-carrying reactions in amino acid and nucleotide metabolism. This computational and experimental methodology expands the scope of metabolic flux analysis beyond carbon metabolism, and may prove important to understanding metabolic phenotypes in health and disease.

  2. Isotopic studies of beach rock carbonates from Konkan, central west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Kumar, B.; Rajamanickam, G.V.; Gujar, A.R.

    The beach rock carbonates from the 200 km long stretch from Guhagar in the north to Deogad in the south along the Konkan coast (Maharashtra, India) are studied for sup(14)C dating and sup(13)C : sup(12)C and sup(18)O : sup(16)O ratio determination...

  3. Pathways of carbon oxidation in continental margin sediments off central Chile

    DEFF Research Database (Denmark)

    Thamdrup, B; Canfield, Donald Eugene

    1996-01-01

    Rates and oxidative pathways of organic carbon mineralization were determined in sediments at six stations on the shelf and slope off Concepcion Bay at 36.5 degrees S. The depth distribution of C oxidation rates was determined to 10 cm from accumulation of dissolved inorganic C in 1-5-d incubatio...

  4. Carbon cycling and carbon metabolism by soil fungi in a boreal forest: impacts of wildfire and permafrost on functional genes, isotope signatures, and ectomycorrhizae

    Science.gov (United States)

    Waldrop, M. P.; Harden, J. W.

    2006-12-01

    carbon for microbial metabolism. Ectomycorrhizal mats occurred only in control soils and increased fungal biomass, functional gene abundance, enzyme activities and process rates compared to non-mat soils. Taken together these results indicate that linkages can be made between the distribution of soil microbial communities, molecular scale information, and soil carbon dynamics.

  5. Ecological network analysis for carbon metabolism of eco-industrial parks: a case study of a typical eco-industrial park in Beijing.

    Science.gov (United States)

    Lu, Yi; Chen, Bin; Feng, Kuishuang; Hubacek, Klaus

    2015-06-16

    Energy production and industrial processes are crucial economic sectors accounting for about 62% of greenhouse gas (GHG) emissions globally in 2012. Eco-industrial parks are practical attempts to mitigate GHG emissions through cooperation among businesses and the local community in order to reduce waste and pollution, efficiently share resources, and help with the pursuit of sustainable development. This work developed a framework based on ecological network analysis to trace carbon metabolic processes in eco-industrial parks and applied it to a typical eco-industrial park in Beijing. Our findings show that the entire metabolic system is dominated by supply of primary goods from the external environment and final demand. The more carbon flows through a sector, the more influence it would exert upon the whole system. External environment and energy providers are the most active and dominating part of the carbon metabolic system, which should be the first target to mitigate emissions by increasing efficiencies. The carbon metabolism of the eco-industrial park can be seen as an evolutionary system with high levels of efficiency, but this may come at the expense of larger levels of resilience. This work may provide a useful modeling framework for low-carbon design and management of industrial parks.

  6. Coral-algae metabolism and diurnal changes in the CO2-carbonate system of bulk sea water

    Directory of Open Access Journals (Sweden)

    Paul L. Jokiel

    2014-05-01

    Full Text Available Precise measurements were conducted in continuous flow seawater mesocosms located in full sunlight that compared metabolic response of coral, coral-macroalgae and macroalgae systems over a diurnal cycle. Irradiance controlled net photosynthesis (Pnet, which in turn drove net calcification (Gnet, and altered pH. Pnet exerted the dominant control on [CO32−] and aragonite saturation state (Ωarag over the diel cycle. Dark calcification rate decreased after sunset, reaching zero near midnight followed by an increasing rate that peaked at 03:00 h. Changes in Ωarag and pH lagged behind Gnet throughout the daily cycle by two or more hours. The flux rate Pnet was the primary driver of calcification. Daytime coral metabolism rapidly removes dissolved inorganic carbon (DIC from the bulk seawater and photosynthesis provides the energy that drives Gnet while increasing the bulk water pH. These relationships result in a correlation between Gnet and Ωarag, with Ωarag as the dependent variable. High rates of H+ efflux continued for several hours following mid-day peak Gnet suggesting that corals have difficulty in shedding waste protons as described by the Proton Flux Hypothesis. DIC flux (uptake followed Pnet and Gnet and dropped off rapidly following peak Pnet and peak Gnet indicating that corals can cope more effectively with the problem of limited DIC supply compared to the problem of eliminating H+. Over a 24 h period the plot of total alkalinity (AT versus DIC as well as the plot of Gnet versus Ωarag revealed a circular hysteresis pattern over the diel cycle in the coral and coral-algae mesocosms, but not the macroalgae mesocosm. Presence of macroalgae did not change Gnet of the corals, but altered the relationship between Ωarag and Gnet. Predictive models of how future global changes will effect coral growth that are based on oceanic Ωarag must include the influence of future localized Pnet on Gnet and changes in rate of reef carbonate

  7. Carbon dioxide and helium dissolved gases in groundwater at central Tenerife Island, Canary Islands: chemical and isotopic characterization

    Science.gov (United States)

    Marrero-Diaz, Rayco; López, Dina; Perez, Nemesio M.; Custodio, Emilio; Sumino, Hirochika; Melián, Gladys V.; Padrón, Eleazar; Hernandez, Pedro A.; Calvo, David; Barrancos, José; Padilla, Germán; Sortino, Francesco

    2015-10-01

    Seismic-volcanic unrest was detected between 2004 and 2005 in the central and northwest zones of Tenerife Island (Canary Islands, Spain). With the aim of strengthening the program of geochemical and seismic-volcanic surveillance, a study of the origin, characteristics, and spatial distribution of dissolved carbon dioxide (CO2) and helium (He) gases in the volcanic aquifer of central Tenerife Island and around Teide volcano was carried out. This work also improves the hydrogeological and hydrogeochemical conceptual model of groundwater flow. Dissolved CO2 concentrations in sampled groundwater are several orders of magnitude higher than that of air-saturated water (ASW) suggesting a significant contribution of non-atmospheric CO2, mainly magmatic, confirmed through measurement of isotopic compositions (δ13CTDIC) and total dissolved inorganic carbon (TDIC) concentrations. A vertical stratification of dissolved CO2 and δ13CTDIC values was observed in the volcanic aquifer at the eastern region of Las Cañadas Caldera. Stratification seems to be controlled by both degree of magmatic CO2-water interaction and CO2 degassing and the original δ13Cco2(g) isotopic composition. The highest dissolved helium (4He) concentrations in groundwater seem to be related to radiogenic contributions resulting from water-rock interactions, and increase with residence time, instead of with endogenous magmatic inputs. Isotopic systematics show that the dissolved gases in groundwater of central Tenerife are variable mixtures of CO2-3He-rich fluids of volcanic-hydrothermal origin with both organic and atmospheric components. The results suggest that the eastern area of Las Cañadas Caldera, the South Volcanic Ridge, and the Teide summit cone are the areas most affected by degassing of the volcanic-hydrothermal system, and they are therefore the most suitable zones for future geochemical monitoring.

  8. Context-dependent metabolic networks

    CERN Document Server

    Beguerisse-Díaz, Mariano; Oyarzún, Diego; Picó, Jesús; Barahona, Mauricio

    2016-01-01

    Cells adapt their metabolism to survive changes in their environment. We present a framework for the construction and analysis of metabolic reaction networks that can be tailored to reflect different environmental conditions. Using context-dependent flux distributions from Flux Balance Analysis (FBA), we produce directed networks with weighted links representing the amount of metabolite flowing from a source reaction to a target reaction per unit time. Such networks are analyzed with tools from network theory to reveal salient features of metabolite flows in each biological context. We illustrate our approach with the directed network of the central carbon metabolism of Escherichia coli, and study its properties in four relevant biological scenarios. Our results show that both flow and network structure depend drastically on the environment: networks produced from the same metabolic model in different contexts have different edges, components, and flow communities, capturing the biological re-routing of metab...

  9. Metabolic responses to the acute ingestion of two commercially available carbonated beverages: A pilot study

    Directory of Open Access Journals (Sweden)

    Mendel Ron W

    2007-09-01

    Full Text Available Abstract Background The purpose of this placebo-controlled, double-blind cross-over study was to compare the effects of two commercially available soft drinks on metabolic rate. Methods After giving informed consent, twenty healthy men and women were randomly assigned to ingest 12 ounces of Celsius™ and, on a separate day, 12 ounces of Diet Coke®. All subjects completed both trials using a randomized, counterbalanced design. Metabolic rate (via indirect calorimetry and substrate oxidation (via respiratory exchange ratio were measured at baseline (pre-ingestion and at the end of each hour for 3 hours post-ingestion. Results Two-way ANOVA revealed a significant interaction (p ® ingestion. No differences in respiratory exchange ratio were noted between trials. Conclusion These preliminary findings indicate Celsius™ has thermogenic properties when ingested acutely. The effects of repeated, chronic ingestion of Celsius™ on body composition are unknown at this time.

  10. Carbon budget of Nyungwe Tropical Montane Rain Forest in Central Africa

    Science.gov (United States)

    Nyirambangutse, B.; Zibera, E.; Uwizeye, F. K.; Hansson, L.; Nsabimana, D.; Pleijel, H.; Uddling, J.; Wallin, G.

    2015-12-01

    African tropical rainforests host rich biodiversity and play many roles at different scales such as local, regional and global, in the functioning of the earth system. Despite that the African tropical forests are the world's second largest, it has been neglected in terms of understanding the storage and fluxes of carbon and other nutrients. The question of whether this biome is a net sink or source of atmospheric CO2 is still not answered, and little is known concerning the climate change response. Tropical montane forests are even more poorly sampled compared with their importance. Deeper understanding of these ecosystems is required to provide insights on how they might react under global change. To answer questions related to these issues for African tropical montane forests, 15 permanent 0.5 ha plots were established in 2011 in Nyungwe tropical montane rainforest gazetted as a National Park to protect its extensive floral and faunal diversity. The plots are arranged along an east-westerly transect and includes both primary and secondary forest communities. The study is connected to the global ecosystem monitoring network (GEM, http://gem.tropicalforests.ox.ac.uk/). The aim is to characterize spatial and temporal heterogeneity of carbon and nutrient dynamics processes. The role of microclimate, topography, human disturbances, and plant species to the variability of these pools and processes will be explored. We compare stocks and fluxes of carbon and nutrients of the secondary and primary forest communities. The carbon stock are determined by an inventory of height and diameter at breast height (dbh) of all trees with a dbh above 5 cm, wood density, biomass of understory vegetation, leaf area index, standing and fallen dead wood, fine root biomass and organic content of various soil layers (litter, organic and mineral soil down to 45 cm depth). The carbon fluxes are determined by measurements of photosynthesis and respiration of leaves, above and below ground

  11. Carbon and nitrogen tracers of land use effects on net ecosystem metabolism in mangrove estuaries, southwest Florida

    Science.gov (United States)

    Dvorak, Matthew; Mora, Germán; Graniero, Lauren; Surge, Donna

    2016-11-01

    Four estuaries in southwest Florida with different land-use characteristics in their watersheds were chosen to investigate the effects of anthropogenic land use on estuarine biogeochemical cycling. We compared C:N ratios, concentrations of dissolved inorganic carbon (DIC), chlorophyll-a (chl-a) and particulate organic carbon (POC), stable isotope ratios of DIC (δ13CDIC) and POC (δ13CPOC), and nitrogen isotope ratios of particulate organic nitrogen (δ15NPON) among these estuaries. Values of δ13CDIC ranged from -14.1 to +0.9‰. The more negative values occurred upstream, resulting from DIC inputs derived from both the degradation of organic carbon and dissolution of carbonates. Upstream DIC concentrations were as high as 8066 μmol L-1, suggesting high respiration rates. Further, a comparison of DIC values to a conservative mixing model indicates net heterotrophic metabolic state in all four estuaries. Supporting this interpretation, low δ13CPOC values suggest that terrestrial plants were the main source of POC in the upstream sampling points. However, C:N ratios ranged from 7.2 to 13.4, and were consistent with the decomposition of both terrestrial and aquatic sources. Chl-a concentrations were variable and typically below 20 μg L-1, indicating moderate to low levels of autotrophy in all estuaries. Elevated chl-a concentrations indicative of increased primary productivity occurred at intermediate salinities, and were possibly caused by the mixing front at mid-estuary locations. There were no apparent differences in δ15NPON among estuaries, suggesting that the N sources to these estuaries are comparable. The combined results show no differences between near-natural and anthropogenically influenced estuaries, indicating a minimal effect of anthropogenic activities on the parameters measured, possibly as a result of the filtering capacity of the extensive surrounding mangrove vegetation.

  12. Radon, carbon dioxide and fault displacements in central Europe related to the Tōhoku Earthquake.

    Science.gov (United States)

    Briestenský, M; Thinová, L; Praksová, R; Stemberk, J; Rowberry, M D; Knejflová, Z

    2014-07-01

    Tectonic instability may be measured directly using extensometers installed across active faults or it may be indicated by anomalous natural gas concentrations in the vicinity of active faults. This paper presents the results of fault displacement monitoring at two sites in the Bohemian Massif and Western Carpathians. These data have been supplemented by radon monitoring in the Mladeč Caves and by carbon dioxide monitoring in the Zbrašov Aragonite Caves. A significant period of tectonic instability is indicated by changes in the fault displacement trends and by anomalous radon and carbon dioxide concentrations. This was recorded around the time of the catastrophic MW=9.0 Tōhoku Earthquake, which hit eastern Japan on 11 March 2011. It is tentatively suggested that the Tōhoku Earthquake in the Pacific Ocean and the unusual geodynamic activity recorded in the Bohemian Massif and Western Carpathians both reflect contemporaneous global tectonic changes.

  13. Radon, carbon dioxide and fault displacements in central Europe related to the Tohoku earthquake

    International Nuclear Information System (INIS)

    Tectonic instability may be measured directly using extensometers installed across active faults or it may be indicated by anomalous natural gas concentrations in the vicinity of active faults. This paper presents the results of fault displacement monitoring at two sites in the Bohemian Massif and Western Carpathians. These data have been supplemented by radon monitoring in the Mladec Caves and by carbon dioxide monitoring in the Zbrasov Aragonite Caves. A significant period of tectonic instability is indicated by changes in the fault displacement trends and by anomalous radon and carbon dioxide concentrations. This was recorded around the time of the catastrophic MW = 9.0 Tohoku Earthquake, which hit eastern Japan on 11 March 2011. It is tentatively suggested that the Tohoku Earthquake in the Pacific Ocean and the unusual geodynamic activity recorded in the Bohemian Massif and Western Carpathians both reflect contemporaneous global tectonic changes. (authors)

  14. The Oligocene-Miocene stratigraphic evolution of the Majella carbonate platform (Central Apennines, Italy)

    Science.gov (United States)

    Brandano, Marco; Cornacchia, Irene; Raffi, Isabella; Tomassetti, Laura

    2016-03-01

    The stratigraphic architecture of the Bolognano Formation documents the evolution of the Majella carbonate platform in response to global and local changes that affected the Mediterranean area during the Oligocene-Miocene interval. The Bolognano Formation consists of a homoclinal ramp that developed in a warm, subtropical environment. Five different lithofacies associations have been identified: Lepidocyclina calcarenites, cherty marly limestones, bryozon calcarenites, hemipelagic marls and marly limestones, and Lithothamnion limestones. Each association corresponds to a single lithostratigraphic unit except for the Lepidocyclina calcarenites that form two distinct lithostratigraphic units (Lepidocyclina calcarenites 1 and 2). These six units reflect alternation of shallow-water carbonate production and drowning. Specifically, two of the three stages of shallow-water carbonate production regard the development of wide dune fields within the middle ramp, one stage dominated by red algae and a sea-grass carbonate factory, whereas the two drowning phases are represented by marly cherty limestones and calcareous marls. A new biostratigraphic framework for Bolognano Formation is presented, based on high-resolution analysis of calcareous nannofossil assemblages, which proved to be very useful for biostratigraphic constraints also in shallow-water settings. Using this approach, we have linked the first drowning phase, late Chattian-Aquitanian p.p. in age, to western Mediterranean volcanism and the Mi-1 event, and the second drowning phase, late Burdigalian-Serravallian in age, to the closure of the Indo-Pacific passage and the occurrence of the global Monterey event. These results permit a new deciphering, in terms of sequence stratigraphy, of the Bolognano Formation that is interpreted as a 2nd-order super-sequence that can be subdivided into 3 transgressive-regressive sequences.

  15. Soybeans grown in the Chernobyl area produce fertile seeds that have increased heavy metal resistance and modified carbon metabolism.

    Directory of Open Access Journals (Sweden)

    Katarína Klubicová

    Full Text Available Plants grow and reproduce in the radioactive Chernobyl area, however there has been no comprehensive characterization of these activities. Herein we report that life in this radioactive environment has led to alteration of the developing soybean seed proteome in a specific way that resulted in the production of fertile seeds with low levels of oil and β-conglycinin seed storage proteins. Soybean seeds were harvested at four, five, and six weeks after flowering, and at maturity from plants grown in either non-radioactive or radioactive plots in the Chernobyl area. The abundance of 211 proteins was determined. The results confirmed previous data indicating that alterations in the proteome include adaptation to heavy metal stress and mobilization of seed storage proteins. The results also suggest that there have been adjustments to carbon metabolism in the cytoplasm and plastids, increased activity of the tricarboxylic acid cycle, and decreased condensation of malonyl-acyl carrier protein during fatty acid biosynthesis.

  16. Proline induces heat tolerance in chickpea (Cicer arietinum L.) plants by protecting vital enzymes of carbon and antioxidative metabolism

    OpenAIRE

    Kaushal, Neeru; Gupta, Kriti; Bhandhari, Kalpna; Kumar, Sanjeev; Thakur, Prince; Nayyar, Harsh

    2011-01-01

    Chickpea is a heat sensitive crop hence its potential yield is considerably reduced under high temperatures exceeding 35 °C. In the present study, we evaluated the efficacy of proline in countering the damage caused by heat stress to growth and to enzymes of carbon and antioxidative metabolism in chickpea. The chickpea seeds were raised without (control) and with proline (10 μM) at temperatures of 30/25 °C, 35/30 °C, 40/35 °C and 45/40 °C as day/ night (12 h/12 h) in a growth chamber. The sho...

  17. The Effect of Different Nitrogen Form on Key Enzyme Activity of Sugarbeet (Vulgaris L.) Carbon and Nitrogen Metabolism

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    This article analyses the effect of the proportion of the different nitrogen forms on key enzyme activity of carbon and nitrogen metabolism under the condition of nutritional water while Tian Yan-7 was used as experimental material. The result showed that nitrate reductase(NR) activity in the leaves gradually enhanced with the increase of NO-3. No matter in root or leaves ,glutamina synthetase (GS) activity first enhanced with increasing NH4+ when NH4+ was lower than that of NO-3 ,and GS activity was the highest when NH4+and NO3-was equal ,then GS activity declined with NH4+ increasing further. In the anaphase of growth ,synthetic activity in root of sucrose synthetase(SS) in the mixed NH4+ and NO3- was obviously highr than or NO3- alone. Both of the root and sugar yields were the highest when the proportion of NH4+ and NO3- was 1: 1.

  18. LIDAR-based urban metabolism approach to neighbourhood scale energy and carbon emissions modelling

    Energy Technology Data Exchange (ETDEWEB)

    Christen, A. [British Columbia Univ., Vancouver, BC (Canada). Dept. of Geography; Coops, N. [British Columbia Univ., Vancouver, BC (Canada). Dept. of Forest Sciences; Canada Research Chairs, Ottawa, ON (Canada); Kellet, R. [British Columbia Univ., Vancouver, BC (Canada). School of Architecture and Landscape Architecture

    2010-07-01

    A remote sensing technology was used to model neighbourhood scale energy and carbon emissions in a case study set in Vancouver, British Columbia (BC). The study was used to compile and aggregate atmospheric carbon flux, urban form, and energy and emissions data in a replicable neighbourhood-scale approach. The study illustrated methods of integrating diverse emission and uptake processes on a range of scales and resolutions, and benchmarked comparisons of modelled estimates with measured energy consumption data obtained over a 2-year period from a research tower located in the study area. The study evaluated carbon imports, carbon exports and sequestration, and relevant emissions processes. Fossil fuel emissions produced in the neighbourhood were also estimated. The study demonstrated that remote sensing technologies such as LIDAR and multispectral satellite imagery can be an effective means of generating and extracting urban form and land cover data at fine scales. Data from the study were used to develop several emissions reduction and energy conservation scenarios. 6 refs.

  19. Transcriptome landscape of Lactococcus lactis reveals many novel RNAs including a small regulatory RNA involved in carbon uptake and metabolism.

    Science.gov (United States)

    van der Meulen, Sjoerd B; de Jong, Anne; Kok, Jan

    2016-01-01

    RNA sequencing has revolutionized genome-wide transcriptome analyses, and the identification of non-coding regulatory RNAs in bacteria has thus increased concurrently. Here we reveal the transcriptome map of the lactic acid bacterial paradigm Lactococcus lactis MG1363 by employing differential RNA sequencing (dRNA-seq) and a combination of manual and automated transcriptome mining. This resulted in a high-resolution genome annotation of L. lactis and the identification of 60 cis-encoded antisense RNAs (asRNAs), 186 trans-encoded putative regulatory RNAs (sRNAs) and 134 novel small ORFs. Based on the putative targets of asRNAs, a novel classification is proposed. Several transcription factor DNA binding motifs were identified in the promoter sequences of (a)sRNAs, providing insight in the interplay between lactococcal regulatory RNAs and transcription factors. The presence and lengths of 14 putative sRNAs were experimentally confirmed by differential Northern hybridization, including the abundant RNA 6S that is differentially expressed depending on the available carbon source. For another sRNA, LLMGnc_147, functional analysis revealed that it is involved in carbon uptake and metabolism. L. lactis contains 13% leaderless mRNAs (lmRNAs) that, from an analysis of overrepresentation in GO classes, seem predominantly involved in nucleotide metabolism and DNA/RNA binding. Moreover, an A-rich sequence motif immediately following the start codon was uncovered, which could provide novel insight in the translation of lmRNAs. Altogether, this first experimental genome-wide assessment of the transcriptome landscape of L. lactis and subsequent sRNA studies provide an extensive basis for the investigation of regulatory RNAs in L. lactis and related lactococcal species. PMID:26950529

  20. Seasonal variations of water-soluble organic carbon, dicarboxylic acids, ketoacids, and α-dicarbonyls in the central Himalayan aerosols

    Directory of Open Access Journals (Sweden)

    K. Kawamura

    2012-01-01

    Full Text Available Aerosol samples were collected from a high elevation mountain site (Nainital, India; 1958 m a.s.l. in the central Himalayas, which provide an isolated platform above the planetary boundary layer to better understand the composition of the remote continental troposphere. The samples were analyzed for water-soluble dicarboxylic acids (C2–C12 and related compounds (ketocarboxylic acids and α-dicarbonyls, as well as organic carbon, elemental carbon and water soluble organic carbon. The contributions of total dicarboxylic acids to total aerosol carbon during wintertime were 1.7 and 1.8%, for day and night, respectively whereas they significantly reduced during summer. Molecular distributions of diacids demonstrated that oxalic (C2 acid was the most abundant species followed by C4 and C3 diacids. The average concentrations of total diacids (433 ± 108 ng m−3, ketoacids (48 ± 23 ng m−3, and α-dicarbonyls (9 ± 4 ng m−3 were similar to those from Asian cities such as Tokyo, Beijing and Hong Kong. During summer season most of the organic species were several times more abundant than in winter. Phthalic acid, which originates from oxidation of polycyclic aromatic hydrocarbons such as naphthalene, was found to be 7 times higher in summer than winter. This feature has not been reported in atmospheric aerosols. Based on molecular distributions and air mass backward trajectories, we report that dicarboxylic acids and related compounds in Himalayan aerosols are influenced by the anthropogenic activities from highly populated Indo-Gangetic plain areas.

  1. Effect of U and {sup 137}Cs chronic contamination on dopamine and serotonin metabolism in the central nervous system of the rat

    Energy Technology Data Exchange (ETDEWEB)

    Houpert, P.; Lestaevel, P. [Inst. de Radioprotection et de Surete Nucleaire (IRSN), Inst. de Radioprotection et de Surete Nucleaire, Dept. de la RadioProtection de l' Homme, Service de RadioBiologie et d' Epidemiologie, Lab. RadioToxicologie experimentale, Pierrelatte (France)]. E-mail: philippe.lestaevel@irsn.fr; Amourette, C. [Centre de Recherches du Service de Sante des Armees Emile Parde, Dept. de Radiobiologie et Radiopathologie, La Tronche (France); Dhieux, B.; Bussy, C.; Paquet, F. [Inst. de Radioprotection et de Surete Nucleaire (IRSN), Inst. de Radioprotection et de Surete Nucleaire, Dept. de la RadioProtection de l' Homme, Service de RadioBiologie et d' Epidemiologie, Lab. RadioToxicologie experimentale, Pierrelatte (France)

    2004-02-01

    Following the Chernobyl accident, the most significant problem for the population of the former Soviet Union for the next 50-70 years will be chronic internal contamination by radionuclides. One of the few experiments carried out in this field reported that neurotransmitter metabolism in the central nervous system of the rat was disturbed after feeding with oats contaminated by {sup 137}Cs for 1 month. The present study assessed the effect of chronic contamination by depleted U or {sup 137}Cs on the metabolism of two neurotransmitters in cerebral areas of rats. Dopamine and serotonin were chosen because their metabolism has been shown to be disturbed after external irradiation, even at moderate doses. Dopamine, serotonin, and some of their catabolites were measured by high-pressure liquid chromatography coupled with an electrochemical detector in five cerebral structures of rats contaminated over a 1-month period by drinking water (40 mg U{center_dot}L{sup -1} or 6500 Bq {sup 137}Cs{center_dot}L{sup -1}). In the striatum, hippocampus, cerebral cortex, thalamus, and cerebellum, the dopamine, serotonin, and catabolite levels were not significantly different between the control rats and rats contaminated by U or {sup 137}Cs. These results are not in accordance with those previously described. (author)

  2. Altered white matter metabolism in delayed neurologic sequelae after carbon monoxide poisoning: A proton magnetic resonance spectroscopic study.

    Science.gov (United States)

    Kuroda, Hiroshi; Fujihara, Kazuo; Mugikura, Shunji; Takahashi, Shoki; Kushimoto, Shigeki; Aoki, Masashi

    2016-01-15

    Proton magnetic resonance spectroscopy ((1)H-MRS) was recently used to examine altered metabolism in the white matter (WM) of patients experiencing carbon monoxide (CO) poisoning; however, only a small number of patients with delayed neurologic sequelae (DNS) were analyzed. We aimed to detect altered metabolism in the WM of patients with DNS using (1)H-MRS; to explore its clinical relevance in the management of patients experiencing CO poisoning. Patients experiencing acute CO poisoning underwent (1)H-MRS and cerebrospinal fluid (CSF) examination within 1week and at 1month after acute poisoning. Metabolites including choline-containing compounds (Cho), creatine (Cr), N-acetylaspartate (NAA), and lactate were measured from the periventricular WM. Myelin basic protein (MBP) concentrations were measured in CSF. Fifty-two patients experiencing acute CO poisoning (15 with DNS, 37 without DNS; median age, 49years; 65% males) underwent (1)H-MRS. Within 1week, NAA/Cr ratios, reflecting neuroaxonal viability, were lower in patients with DNS than in those without DNS (PDNS, Cho/Cr ratios were higher, and NAA/Cr and NAA/Cho ratios lower in patients with DNS (P=0.0001, DNS development; (1)H-MRS at 1month may be useful for discriminating patients with DNS and predicting long-term outcomes. PMID:26723994

  3. Metabolism and distribution of 14C- and 35S-labeled carbon disulfide in immature rats of different ages

    International Nuclear Information System (INIS)

    The metabolism and distribution of 14C- and 35S-CS2 was examined in 1-, 5-, 10-, 20-, 30-, and 40-day-old rats. During a 3-hr period following an ip dose of 14C-CS2, 58-83% of the dose was expired as CS2 and 4-9% was metabolized to expired CO2 depending on age. Thirty- and forty-day-old rats metabolized significantly more CS2 to CO2 and expired significantly less CS2 than 1- through 20-day-old rats. At the end of the measured expiration period, only biotransformation products of CS2, which were in part covalently bound, remained in tissues from rats of all ages. Tissue levels of 35S-CS2-derived radioactivity exceeded levels of 14C-CS2-derived radioactivity indicating that sulfur metabolites free from the carbon atom of CS2 were formed in rats as young as 1 day of age. The 35S-CS2-derived radioactivity per g of tissue and thus 35S covalently bound to tissue protein was significantly higher in 1- through 20-day-old rats than in 30- and 40-day-old rats. Twenty-four hr after dosing, up to 13 times more 35S-labeled metabolites were covalently bound in organs from 1-day-old rats than in similar organs from 40-day-old rats. The results showed that elimination of the biotransformation products of CS2, in particular the covalently binding sulfur metabolites, was prolonged in newborn rats in comparison to 40-day-old rats

  4. Growth, biomass, carbon storage and nutrient distribution in Gmelina arborea Roxb. stands on red lateritic soils in central India.

    Science.gov (United States)

    Swamy, S L; Puri, S; Singh, A K

    2003-11-01

    Growth, biomass, carbon storage and nutrient (N, P and K) variations in 1 to 6-year-old chronosequence plantations of Gmelina arborea were studied in three degraded red lateritic sites in central India. Growth parameters (dbh, total height and number of branches) varied significantly due to difference in age and site quality, but tree density showed non-significant variation. Stand biomass ranged from 3.94 (1-year-old) to 53.67 Mgha(-1) (6-year-old) and stand carbon in 6-year-old plantations ranged from 24.12 to 31.12 Mgha(-1) at different sites. Among the tree components, the stem wood accounted for maximum C (56.25% at site 1) followed by branches (19.8% at site 3), roots (18.51% at site 2) and foliage (7.01% at site 3). Mean annual C accretion at 6 years age of plantation was highest in site 3 and it was 0.35, 2.66, 0.965 and 0.87 Mgha(-1) for leaf, stem, branches and roots, respectively. Quantity of nutrients increased with age. Total nitrogen accumulation in 6-year-old stands at the three sites ranged from 212.9 to 279.5 kgha(-1) with a mean annual storage of 238.43 kgha(-1) and total K ranged from 170.8 to 220.5 kgha(-1) with a mean annual storage of 189.93 kgha(-1). Phosphorous accumulation was lowest with a mean storage of 16.75 kgha(-1). The organic carbon and nutrients in the soils improved significantly after 6 years of G. arborea planting. Soil organic carbon increased from 8.46 to 14.02 Mgha(-1) within 6 years. At soil depths 0-20 cm, 21-40 cm and 41-60 cm, available N enhanced by 14.85%, 11.98% and 11.25%, K by 10%, 9.13% and 10.63%, whereas phosphorous declined by 26%, 23% and 20%, respectively. At 6 years, G. arborea stands sequestered 31.37 Mgha(-1) carbon. The nutrient management strategies in relation to carbon accretion in G. arborea stands on degraded lateritic sites are discussed. PMID:12895553

  5. Dynamics of seawater carbonate chemistry, production, and calcification of a coral reef flat, central Great Barrier Reef

    Directory of Open Access Journals (Sweden)

    R. Albright

    2013-10-01

    Full Text Available Ocean acidification is projected to shift coral reefs from a state of net accretion to one of net dissolution this century. Presently, our ability to predict global-scale changes to coral reef calcification is limited by insufficient data relating seawater carbonate chemistry parameters to in situ rates of reef calcification. Here, we investigate diel and seasonal trends in carbonate chemistry of the Davies Reef flat in the central Great Barrier Reef and relate these trends to benthic carbon fluxes by quantifying net ecosystem calcification (nec and net community production (ncp. Results show that seawater carbonate chemistry of the Davies Reef flat is highly variable over both diel and seasonal cycles. pH (total scale ranged from 7.92 to 8.17, pCO2 ranged from 272 to 542 μatm, and aragonite saturation state (Ωarag ranged from 2.9 to 4.1. Diel cycles in carbonate chemistry were primarily driven by ncp, and warming explained 35% and 47% of the seasonal shifts in pCO2 and pH, respectively. Daytime ncp averaged 37 ± 19 mmol C m−2 h−1 in summer and 33 ± 13 mmol C m−2 h−1 in winter; nighttime ncp averaged −30 ± 25 and −7 ± 6 mmol C m−2 h−1 in summer and winter, respectively. Daytime nec averaged 11 ± 4 mmol CaCO3 m−2 h−1 in summer and 8 ± 3 mmol CaCO3 m−2 h−1 in winter, whereas nighttime nec averaged 2 ± 4 mmol and −1 ± 3 mmol CaCO3 m−2 h−1 in summer and winter, respectively. Net ecosystem calcification was highly sensitive to changes in Ωarag for both seasons, indicating that relatively small shifts in Ωarag may drive measurable shifts in calcification rates, and hence carbon budgets, of coral reefs throughout the year.

  6. Effect of carbon tetrachloride on glycogen metabolism in fasted and refed mice

    International Nuclear Information System (INIS)

    Hepatic glycogen was depleted rapidly in fasted mice treated with CCl4. Glycogen breakdown was slow when CCl4 was administered after 1 hr of refeeding. There was an initial increase and then a reduction in liver glycogen of mice refed for 2 hr prior to CCl4 injection. The incorporation of glucose-U-14C into glycogen was higher in mice which were refed before CCl4 administration than in fasted mice treated with the hepatotoxin. The specific activity of lactate was higher in CCl4 treated mice. The data suggested differences in glycogen metabolism of fasted and refed mice in response to CCl4 treatment. (author)

  7. Adaptive evolution of complex innovations through stepwise metabolic niche expansion.

    Science.gov (United States)

    Szappanos, Balázs; Fritzemeier, Jonathan; Csörgő, Bálint; Lázár, Viktória; Lu, Xiaowen; Fekete, Gergely; Bálint, Balázs; Herczeg, Róbert; Nagy, István; Notebaart, Richard A; Lercher, Martin J; Pál, Csaba; Papp, Balázs

    2016-01-01

    A central challenge in evolutionary biology concerns the mechanisms by which complex metabolic innovations requiring multiple mutations arise. Here, we propose that metabolic innovations accessible through the addition of a single reaction serve as stepping stones towards the later establishment of complex metabolic features in another environment. We demonstrate the feasibility of this hypothesis through three complementary analyses. First, using genome-scale metabolic modelling, we show that complex metabolic innovations in Escherichia coli can arise via changing nutrient conditions. Second, using phylogenetic approaches, we demonstrate that the acquisition patterns of complex metabolic pathways during the evolutionary history of bacterial genomes support the hypothesis. Third, we show how adaptation of laboratory populations of E. coli to one carbon source facilitates the later adaptation to another carbon source. Our work demonstrates how complex innovations can evolve through series of adaptive steps without the need to invoke non-adaptive processes. PMID:27197754

  8. Carbonate cementation as related to the diagenesis of clay in a mixed siliciclastic-carbonate system: Examples from the Centerfield biostrome, east central Pennsylvania

    Energy Technology Data Exchange (ETDEWEB)

    Burns, C.D. (Univ. of North Carolina, Chapel Hill, NC (United States))

    1994-03-01

    The Middle Devonian Mahantango Formation consists of siliciclastic and mixed carbonate-siliciclastic sediment packages that pulse in and out of the stratigraphy. The formation crops out in several places throughout the folded rocks of eastern Pennsylvania and Maryland. The Centerfield Member is one of the mixed siliciclastic-carbonate packages in the Mahantango Fm. This member crops out in east central Pennsylvania. The Centerfield Mbr. has been interpreted as a series of biostromes and contain abundant rugosan corals, crinoids, bryozoans, and brachiopods. The biostromes have undergone a complex diagenetic history. Illite, smectite, chlorite and muscovite have been found with the use of powder x-ray diffraction and petrographic analysis. The smectite and some of the illite are depositional clays, while, the remaining illite, chlorite and muscovite represent recrystallization of the depositional clays. There are six phases of cement in the biostrome. The paragenetic sequence of the cements is as follows: non-ferroan low magnesian calcite (LMC), intermediate ferroan LMC, ferroan LMC, non-ferroan dolomite, ferroan baroque dolomite, and quartz cement in the form of chert and blocky cement. Staining shows that the iron content of the cement changes within individual crystals and between cement phases. Preliminary data suggest that the cements may be directly related to the steady release of ions during the diagenesis of the surrounding clays in the shale.

  9. Carbon budget in the eastern and central Arabian Sea: An Indian JGOFS synthesis

    Digital Repository Service at National Institute of Oceanography (India)

    Sarma, V.V.S.S.; Swathi, P.S.; DileepKumar, M.; PrasannaKumar, S.; Bhattathiri, P.M.A.; Madhupratap, M.; Ramaswamy, V.; Sarin, M.M.; Gauns, M.; Ramaiah, N.; Sardessai, S.; DeSousa, S.N.

    of its unique monsoon-driven, dynamic, and complex biogeochemistry. The JGOFS (India) I HydfOsphcric-!\\tlllosphcri<: Research Center. Nagoya University, Nagoya, Japan. 2CS1R Centre ti.1r 'Aathcmutical 'Aodeling and Computer Simulation, Banr,alore-: India.... Our assumption is supported by small variability in TOC observed in U.S.-JGOFS [Hal/sell and Pellcer, 199RJ. We believe that the uncertainties associated with the considered constancy of TOe would not affect final trends in carbon TCO,~297S.9 - 19.9T...

  10. The overexpression of the pine transcription factor PpDof5 in Arabidopsis leads to increased lignin content and affects carbon and nitrogen metabolism.

    Science.gov (United States)

    Rueda-López, Marina; Cañas, Rafael A; Canales, Javier; Cánovas, Francisco M; Ávila, Concepción

    2015-12-01

    PpDof 5 is a regulator of the expression of glutamine synthetase (GS; EC 6.3.1.2) genes in photosynthetic and non-photosynthetic tissues of maritime pine. We have used Arabidopsis thaliana as a model system to study PpDof 5 function in planta, generating transgenic lines overexpressing the pine transcription factor. The overexpression of PpDof 5 resulted in a substantial increase of lignin content with a simultaneous regulation of carbon and nitrogen key genes. In addition, partitioning in carbon and nitrogen compounds was spread via various secondary metabolic pathways. These results suggest pleiotropic effects of PpDof 5 expression on various metabolic pathways of carbon and nitrogen metabolism. Plants overexpressing PpDof 5 exhibited upregulation of genes encoding enzymes for sucrose and starch biosynthesis, with a parallel increase in the content of soluble sugars. When the plants were grown under nitrate as the sole nitrogen source, they exhibited a significant regulation of the expression of genes involved mainly in signaling, but similar growth rates to wild-type plants. However, plants grown under ammonium exhibited major induction of the expression of photosynthetic genes and differential expression of ammonium and nitrate transporters. All these data suggest that in addition to controlling ammonium assimilation, PpDof 5 could be also involved in the regulation of other pathways in carbon and nitrogen metabolism in pine trees. PMID:26333592

  11. 犬尿氨酸代谢通路与中枢神经系统%The Kynurenine Metabolic Pathway and the Central Nervous System

    Institute of Scientific and Technical Information of China (English)

    李宁宁; 高平进

    2008-01-01

    The kynurenine metabolic pathway involves in a cascade of enzyme reaction generated multiple biologically-active compounds.These metabolites are called"kynurenines" which participate in diverse pathophysiological processes,particularly in the central nervous system.The kynurenines have important physiological functions.For example.quinolinic acid is an Nmethyl-D-aspartate(NMDA)receptor agonist.and it can be largely accumulated in the central nervous system in many infectious nervous system diseases,resulting in neuronal excitotoxicity and death.Kynurenic acid antagonizes excitatory glutamate receptors to reduce excitotoxicityinduced neuronal death.This article reviews the related researches of the effects of kynurenine metabolic pathway on the central nervous system.%犬尿氨酸代谢通路涉及一系列酶促反应,生成多种具有生物学活性的化合物,这些代谢产物统称为"犬尿氨酸能物质".犬尿氨酸能物质参与多种病理生理学过程,在中枢神经系统中有着重要的生理功能.例如,喹咻酸是N-甲基-D-天冬氨酸受体激动剂,在许多感染性神经系统疾病中可大量堆积在中枢神经系统,导致神经元因兴奋性中毒而死亡.犬尿喹啉酸可拮抗兴奋性谷氨酸盐受体,减少因兴奋性中毒导致的神经元死亡.文章就犬尿氨酸代谢通路在中枢神经系统中作用的相关研究做了综述.

  12. Analysis of metabolic alterations in Arabidopsis following changes in the carbon dioxide and oxygen partial pressures

    Institute of Scientific and Technical Information of China (English)

    Alexandra Florian; Stefan Timm; Zoran Nikoloski; Takayuki Tohge; Hermann Bauwe; Wagner LArajo; Alisdair RFernie

    2014-01-01

    As sessile organisms, plants are subject to a multitude of environmental variations including several which directly affect their interaction with the atmosphere. Given the indiscriminant nature of Rubisco, the relative rates of photosynthesis and photorespiration are known to be responsive to changes in gas composition. However, compre-hensive profiling methods have not yet been applied in order to characterize the wider consequences of these changes on primary metabolism in general. Moreover, although transcrip-tional profiling has revealed that a subset of photorespiratory enzymes are co-expressed, whether transcriptional responses play a role in short-term responses to atmospheric composi-tional changes remains unknown. To address these questions, plants Arabidopsis thaliana (Arabidopsis) ecotype Columbia (Col-O) grown under normal air conditions were transferred to different CO2 and O2 concentrations and characterized at the physiological, molecular, and metabolic levels fol owing this transition. The results reveal alterations in the components, which are directly involved in, or supporting, photorespiration, including transcripts and metabolite levels. The results further highlight that the majority of the regulation of these pathways is not mediated at the level of transcription and that the photorespiratory pathway is essential also in conditions in which flux through the pathway is minimized, yet suggest that flux through this pathway is not mediated at the level of transcription.

  13. In vivo 13 carbon metabolic imaging at 3T with hyperpolarized 13C-1-pyruvate.

    Science.gov (United States)

    Kohler, S J; Yen, Y; Wolber, J; Chen, A P; Albers, M J; Bok, R; Zhang, V; Tropp, J; Nelson, S; Vigneron, D B; Kurhanewicz, J; Hurd, R E

    2007-07-01

    We present for the first time dynamic spectra and spectroscopic images acquired in normal rats at 3T following the injection of (13)C-1-pyruvate that was hyperpolarized by the dynamic nuclear polarization (DNP) method. Spectroscopic sampling was optimized for signal-to-noise ratio (SNR) and for spectral resolution of (13)C-1-pyruvate and its metabolic products (13)C-1-alanine, (13)C-1-lactate, and (13)C-bicarbonate. Dynamic spectra in rats were collected with a temporal resolution of 3 s from a 90-mm axial slab using a dual (1)H-(13)C quadrature birdcage coil to observe the combined effects of metabolism, flow, and T(1) relaxation. In separate experiments, spectroscopic imaging data were obtained during a 17-s acquisition of a 20-mm axial slice centered on the rat kidney region to provide information on the spatial distribution of the metabolites. Conversion of pyruvate to lactate, alanine, and bicarbonate occurred within a minute of injection. Alanine was observed primarily in skeletal muscle and liver, while pyruvate, lactate, and bicarbonate concentrations were relatively high in the vasculature and kidneys. In contrast to earlier work at 1.5 T, bicarbonate was routinely observed in skeletal muscle as well as the kidney and vasculature. PMID:17659629

  14. Proteomic Analysis of the Hydrogen and Carbon Monoxide Metabolism of Methanothermobacter marburgensis

    Science.gov (United States)

    Diender, Martijn; Pereira, Ricardo; Wessels, Hans J. C. T.; Stams, Alfons J. M.; Sousa, Diana Z.

    2016-01-01

    Hydrogenotrophic methanogenic archaea are efficient H2 utilizers, but only a few are known to be able to utilize CO. Methanothermobacter thermoautotrophicus is one of the hydrogenotrophic methanogens able to grow on CO, albeit about 100 times slower than on H2 + CO2. In this study, we show that the hydrogenotrophic methanogen Methanothermobacter marburgensis, is able to perform methanogenic growth on H2/CO2/CO and on CO as a sole substrate. To gain further insight in its carboxydotrophic metabolism, the proteome of M. marburgensis, grown on H2/CO2 and H2/CO2/CO, was analyzed. Cultures grown with H2/CO2/CO showed relative higher abundance of enzymes involved in the reductive acetyl-CoA pathway and proteins involved in redox metabolism. The data suggest that the strong reducing capacity of CO negatively affects hydrogenotrophic methanogenesis, making growth on CO as a sole substrate difficult for this type of methanogens. M. marburgensis appears to partly deal with this by up-regulating co-factor regenerating reactions and activating additional pathways allowing for formation of other products, like acetate.

  15. Moderate voluntary exercise attenuates the metabolic syndrome in melanocortin-4 receptor-deficient rats showing central dopaminergic dysregulation

    Directory of Open Access Journals (Sweden)

    Silvana Obici

    2015-10-01

    Conclusions: Central dopamine dysregulation during VWR reinforces the link between MC4R function and molecular and behavioral responding to rewards. The data also suggest that exercise can be a successful lifestyle intervention in MC4R-haploinsufficient individuals despite reduced positive reinforcement during exercise training.

  16. Pathway analysis using (13) C-glycerol and other carbon tracers reveals a bipartite metabolism of Legionella pneumophila.

    Science.gov (United States)

    Häuslein, Ina; Manske, Christian; Goebel, Werner; Eisenreich, Wolfgang; Hilbi, Hubert

    2016-04-01

    Amino acids represent the prime carbon and energy source for Legionella pneumophila, a facultative intracellular pathogen, which can cause a life-threatening pneumonia termed Legionnaires' disease. Genome, transcriptome and proteome studies indicate that L. pneumophila also utilizes carbon substrates other than amino acids. We show here that glycerol promotes intracellular replication of L. pneumophila in amoeba or macrophages (but not extracellular growth) dependent on glycerol-3-phosphate dehydrogenase, GlpD. An L. pneumophila mutant strain lacking glpD was outcompeted by wild-type bacteria upon co-infection of amoeba, indicating an important role of glycerol during infection. Isotopologue profiling studies using (13) C-labelled substrates were performed in a novel minimal defined medium, MDM, comprising essential amino acids, proline and phenylalanine. In MDM, L. pneumophila utilized (13) C-labelled glycerol or glucose predominantly for gluconeogenesis and the pentose phosphate pathway, while the amino acid serine was used for energy generation via the citrate cycle. Similar results were obtained for L. pneumophila growing intracellularly in amoeba fed with (13) C-labelled glycerol, glucose or serine. Collectively, these results reveal a bipartite metabolism of L. pneumophila, where glycerol and carbohydrates like glucose are mainly fed into anabolic processes, while serine serves as major energy supply. PMID:26691313

  17. Effects of COD to Phosphorus Ratios on the Metabolism of PAOs in Enhanced Biological Phosphorus Removal with Different Carbon Sources

    Institute of Scientific and Technical Information of China (English)

    Tao Jiang; Junguo He; Xiaonan Yang; Jianzheng Li

    2015-01-01

    To elucidate the phosphorus removal and metabolism under various COD/P ratio, a sludge highly enriched in PAOs was used to investigate the impacts of COD/P in batch tests under different carbon supply conditions. Acetate, propionate and a mixture of acetate and propionate at a ratio of 3 ∶ 1 ( COD basis) was used as carbon sources with the COD/P of 20, 15,10 and 5�0 gCOD/gP, respectively. The minimum COD/P ratios for complete P removal were found to be 8�24 gCOD/gP for acetate, 11�40 gCOD/gP for propionate and 9�10 gCOD/gP for the 3 ∶ 1 mixture of acetate and propionate. Converted to a mass basis, all three cases had a very similar ratio of 7�7 gVFA/gP, which represented a useful guide for operation of EBPR plants to identify possible shortages inVFAs. The trend in PHV accumulation during the anaerobic period along with the decrease of COD/P ratios suggested that, PAOs may use the TCA pathway for anaerobic VFA uptake to maintain the required NADH production with reduced glycogen degradation. During the aerobic phase, the glycogen pool was reduced but remained enough compared to the requirement for anaerobic VFA uptake, and the synthesis and degradation of glycogen was not the inhibition factor of PAOs.

  18. [Effects of exogenous glucose and starch on soil carbon metabolism of root zone and root function in potted sweet cherry].

    Science.gov (United States)

    Zhou, Wen-jie; Zhang, Peng; Qin, Si-jun; Lyu, De-guo

    2015-11-01

    glucose and starch affected soil carbon metabolism and enhanced soil microbial activity, the root respiratory rate and root viability. PMID:26915183

  19. Biosynthesis of chiral 3-hydroxyvalerate from single propionate-unrelated carbon sources in metabolically engineered E. coli

    Directory of Open Access Journals (Sweden)

    Martin Collin H

    2010-11-01

    Full Text Available Abstract Background The ability to synthesize chiral building block molecules with high optical purity is of considerable importance to the fine chemical and pharmaceutical industries. Production of one such compound, 3-hydroxyvalerate (3HV, has previously been studied with respect to the in vivo or in vitro enzymatic depolymerization of biologically-derived co-polymers of poly(3-hydroxybutyrate-co-3-hydroxyvalerate. However, production of this biopolymeric precursor typically necessitates the supplementation of a secondary carbon source (e.g., propionate into the culture medium. In addition, previous approaches for producing 3HV have not focused on its enantiopure synthesis, and thus suffer from increased costs for product purification. Results Here, we report the selective biosynthesis of each 3HV stereoisomer from a single, renewable carbon source using synthetic metabolic pathways in recombinant strains of Escherichia coli. The product chirality was controlled by utilizing two reductases of opposing stereoselectivity. Improvement of the biosynthetic pathway activity and host background was carried out to elevate both the 3HV titers and 3HV/3HB ratios. Overall, shake-flask titers as high as 0.31 g/L and 0.50 g/L of (S-3HV and (R-3HV, respectively, were achieved in glucose-fed cultures, whereas glycerol-fed cultures yielded up to 0.19 g/L and 0.96 g/L of (S-3HV and (R-3HV, respectively. Conclusions Our work represents the first report of direct microbial production of enantiomerically pure 3HV from a single carbon source. Continued engineering of host strains and pathway enzymes will ultimately lead to more economical production of chiral 3HV.

  20. Aphotic zone carbonate production on a Miocene ramp, Central Apennines, Italy

    Science.gov (United States)

    Corda, Laura; Brandano, Marco

    2003-09-01

    The lower Miocene Latium-Abruzzi platform was a low-angle ramp that developed under tropical-to-subtropical conditions, but was dominated by bryomol and rhodalgal sediment associations. The Aquitanian to Serravallian sequence described here paraconformably overlies the Cretaceous limestones. It consists of a lowstand systems tract, a transgressive systems tract and a highstand systems tract. Based on facies analysis and on the light dependence of biotic associations, the ramp is divided into three parts: an inner ramp, a middle ramp and an outer ramp. The inner ramp facies are represented by a few metres of coral framestone, rhodolith floatstone-rudstone and balanid macroids floatstone without wave-related structures. The middle ramp consists of structureless bioclastic grainstone to packstone, floatstone and rudstone with rhodoliths and larger foraminifera. The outer ramp facies—proximal sector—are composed of crudely stratified bryozoan-dominated packstone to floatstone which extend over the whole platform. The outer ramp facies—intermediate sector—are represented by wackestone, packstone and rarely grainstone with foraminifera and echinoid fragments. The final depositional profile of the ramp was strongly influenced by the main organisms producing sediment. During the lowstand, the resulting profile is a ramp type. During the transgressive phase, the rapid spreading of the outer ramp facies belt, as a consequence of the enhanced productivity of the light-independent biota, is believed to be promoted by a change from oligotrophic to eutrophic conditions. Climate and/or tectonics are presumed to have played an important role in continental runoff and then in the nutrients delivery. During the highstand phase, the system returns to rates of production uniform throughout the platform. The high rates of carbonate production occurring in the aphotic zone are quite unusual in tropical settings and represent a provocative trend in apparent contrast with the

  1. Partial Amelioration of Peripheral and Central Symptoms of Huntington’s Disease via Modulation of Lipid Metabolism

    Science.gov (United States)

    Chen, Jane Y.; Tran, Conny; Hwang, Lin; Deng, Gang; Jung, Michael E.; Faull, Kym F.; Levine, Michael S.; Cepeda, Carlos

    2016-01-01

    Background Huntington’s disease (HD) is a fatal, inherited neurodegenerative disorder characterized by uncontrollable dance-like movements, as well as cognitive deficits and mood changes. A feature of HD is a metabolic disturbance that precedes neurological symptoms. In addition, brain cholesterol synthesis is significantly reduced, which could hamper synaptic transmission. Objective Alterations in lipid metabolism as a potential target for therapeutic intervention in the R6/2 mouse model of HD were examined. Methods Electrophysiological recordings in vitro examined the acute effects of cholesterol-modifying drugs. In addition, behavioral testing, effects on synaptic activity, and measurements of circulating and brain tissue concentrations of cholesterol and the ketone β-hydroxybutyrate (BHB), were examined in symptomatic R6/2 mice and littermate controls raised on normal chow or a ketogenic diet (KD). Results Whole-cell voltage clamp recordings of striatal medium-sized spiny neurons (MSNs) from symptomatic R6/2 mice showed increased frequency of spontaneous inhibitory postsynaptic currents (sIPSCs) compared with littermate controls. Incubation of slices in cholesterol reduced the frequency of large-amplitude sIPSCs. Addition of BHB or the Liver X Receptor (LXR) agonist T0901317 reduced the frequency and amplitude of sIPSCs. Surprisingly, incubation in simvastatin to reduce cholesterol levels also decreased the frequency of sIPSCs. HD mice fed the KD lost weight more gradually, performed better in an open field, had fewer stereotypies and lower brain levels of cholesterol than mice fed a regular diet. Conclusions Lipid metabolism represents a potential target for therapeutic intervention in HD. Modifying cholesterol or ketone levels acutely in the brain can partially rescue synaptic alterations, and the KD can prevent weight loss and improve some behavioral abnormalities. PMID:27031732

  2. Effect of Direct Seeding Mulch-Based Systems on Soil Carbon Storage and Macrofauna in Central Brazil

    Directory of Open Access Journals (Sweden)

    Eric Blanchart

    2007-03-01

    Full Text Available Soils represent a large carbon pool, approximately 1500 Gt, equivalent to almost three times the quantity stored in terrestrial biomass and twice the amount stored in the atmosphere. Any modification of land-use or land management can induce variations in soil carbon stocks, even in agricultural systems that are perceived to be in a steady state. These modifications also alter soil macrofauna that is known to affect soil carbon dynamics. Direct seeding Mulch-based Cropping (DMC systems with two crops per year without soil tillage have widely been adopted over the last 10 to 15 years in the Cerrado (central region of Brazil. They are replacing the traditional soybean monocropping with fallow under conventional tillage (CT. The objective of this study was to examine how DMC practices affect soil organic carbon (SOC dynamics and macrofauna (Rio Verde, Goias State. The approach was to determine soil C stocks and macrofauna in five fields under DMC aged 1, 5, 7, 11 and 13 years. In order to compare DMC systems with the native system of the region and previous land-use, a situation under native Cerrado (tree-savanna like vegetation and a field conducted traditionally (CT were also studied. Soil C stocks were calculated for the 0-10 and 0-40 cm soil depth and also for the first 400 kg m-2 of soil to compare the same amount of soil and to suppress the potential artefact of soil compaction when sample is based on fix layer depth. Soil macrofauna was hand-sorted from soil monoliths (30 cm depth, TSBF method. In our study, the annual rate of carbon storage was equal to ca. 1.6 MgC ha-1, which is in the range of values measured for DMC in different areas of Brazil, i.e., 0.4 to 1.7 MgC ha-1 with the highest rates obtained in the Cerrado region. Compared to natural vegetation, soil macrofauna in cropped systems was strongly modified. In CT, biomass and density were very low and much lower than in DMC systems. With increasing age of DMC, total macrofauna

  3. Dynamics of seawater carbonate chemistry, production, and calcification of a coral reef flat, Central Great Barrier Reef

    Directory of Open Access Journals (Sweden)

    R. Albright

    2013-05-01

    Full Text Available Ocean acidification is projected to shift coral reefs from a state of net accretion to one of net dissolution this century. Presently, our ability to predict global-scale changes to coral reef calcification is limited by insufficient data relating seawater carbonate chemistry parameters to in situ rates of reef calcification. Here, we investigate natural trends in carbonate chemistry of the Davies Reef flat in the central Great Barrier Reef on diel and seasonal timescales and relate these trends to benthic carbon fluxes by quantifying net ecosystem calcification (nec and net community production (ncp. Results show that seawater carbonate chemistry of the Davies Reef flat is highly variable over both diel and seasonal timescales. pH (total scale ranged from 7.92 to 8.17, pCO2 ranged from 272 to 542 μatm, and aragonite saturation state (Ωarag ranged from 2.9 to 4.1. Diel cycles in carbonate chemistry were primarily driven by ncp, and warming explained 35% and 47% of the seasonal shifts in pCO2 and pH, respectively. Daytime ncp averaged 36 ± 19 mmol C m−2 h−1 in summer and 33 ± 13 mmol C m−2 h−1 in winter; nighttime ncp averaged −22 ± 20 and −7 ± 6 mmol C m−2 h−1 in summer and winter, respectively. Daytime nec averaged 11 ± 4 mmol CaCO3 m−2 h−1 in summer and 8 ± 3 mmol CaCO3 m−2 h−1 in winter, whereas nighttime nec averaged 2 ± 4 mmol and −1 ± 3 mmol CaCO3 m−2 h−1 in summer and winter, respectively. Net ecosystem calcification was positively correlated with Ωarag for both seasons. Linear correlations of nec and Ωarag indicate that the Davies Reef flat may transition from a state of net calcification to net dissolution at Ωarag values of 3.4 in summer and 3.2 in winter. Diel trends in Ωarag indicate that the reef flat is currently below this calcification threshold 29.6% of the time in summer and 14.1% of the time in winter.

  4. Oral facial clefts and gene polymorphisms in metabolism of folate/one-carbon and vitamin A

    DEFF Research Database (Denmark)

    Boyles, Abee L; Wilcox, Allen J; Taylor, Jack A;

    2009-01-01

    An increased risk of facial clefts has been observed among mothers with lower intake of folic acid or vitamin A around conception. We hypothesized that the risk of clefts may be further moderated by genes involved in metabolizing folate or vitamin A. We included 425 case-parent triads in which......-Marker (TRIMM) approach we performed SNP, gene, chromosomal region, and pathway-wide association tests of child or maternal genetic effects for both CL/P and CPO. We stratified these analyses on maternal intake of folic acid or vitamin A during the periconceptional period. As expected with this high number...... of statistical tests, there were many associations with P-valuesfolic acid reduces the risk of CL/P in these data...

  5. soil carbon pools within oak forest is endangered by global climate change in central mexico

    Science.gov (United States)

    García-Oliva, Felipe; Merino, Agustín; González-Rodriguez, Antonio; Chávez-Vergara, Bruno; Tapia-Torres, Yunuen; Oyama, Ken

    2016-04-01

    Forest soil represents the main C pool in terrestrial ecosystems. In particular, temperate forest ecosystems play an important role in the C budget among tropical countries, such as Mexico. For example, the temperate forest ecosystem contains higher C contents on average (295 Mg C ha-1) than the soil C associated with other ecosystems in Mexico (between 56 to 287 Mg C ha-1). At a regional scale, oak forest has the highest C content (460 Mg C ha-1) among the forest ecosystem in Michoacán State at Central Mexico. At the local scale, the soil C content is strongly affected by the composition of organic matter produced by the plant species. The oak species are very diverse in Mexico, distributed within two sections: Quercus sensu stricto and Lobatae. The oak species from Quercus s.s. section produced litterfall with lower concentrations of recalcitrant and thermostable compounds than oak species from Lobatae section, therefore the soil under the former species had higher microbial activity and nutrient availability than the soil under the later species. However, the forest fragment with higher amount of oak species from Quercus s.s. section increases the amount of soil C contents. Unfortunately, Quercus species distribution models for the central western region of Mexico predict a decrease of distribution area of the majority of oak species by the year 2080, as a consequence of higher temperatures and lower precipitation expected under climate change scenarios. Additionally to these scenarios, the remnant oak forest fragments suffer strong degradation due to uncontrolled wood extraction and deforestation. For this reason, the conservation of oak forest fragments is a priority to mitigate the greenhouse gases emission to the atmosphere. In order to enhance the protection of these forest fragments it is required that the society identify the ecosystem services that are provided by these forest fragments.

  6. Vertical flux of particulate organic carbon in the central South China Sea estimated from 234Th-238U disequilibria

    Institute of Scientific and Technical Information of China (English)

    MA Hao; ZENG Zhi; HE Jianhua; CHEN Liqi; YIN Mingduan; ZENG Shi; ZENG Wenyi

    2008-01-01

    234Th-238u disequilibria were applied to examine the particle dynamics in the euphotic zone of the central South China Sea during the spring 2002 cruise. The particulate organic carbon (POC), 234Th (including both dissolved and particulate) and 238U in the water column at three stations were determined. The profiles of 234Th/238U activity ratio at the three stations all showed consistent 234Th deficit as compared to 238U in the upper 100 m water column. Based on the profiles of the dissolved and particulate 234Th and a steady state box model, the dissolved 234Th scavenging rates, the particulate 234Th removal rates and their resident times were quantified. It was found that the POC downward export fluxes out of the upper 100 m euphotic zone ranged from 9.40 to 14.78 mmol.m-2.d-1. The results from this study provide new information for our understanding of carbon biogeochemical cycle in the South China Sea.

  7. Carbon nanotubes toxicology and effects on metabolism and immunological modification in vitro and in vivo

    International Nuclear Information System (INIS)

    The aim of this research is focused on the biological effects of multi wall carbon nanotubes (MWCNTs) on three different human cell types, laboratory animals in vivo, and immunological effects. Large numbers of researchers are directly involved in the handling of nanostructured materials such as MWCNTs and nanoparticles. It is important to assess the potential health risks related to their daily exposure to carbon nanotubes. The administration of sterilized nanosamples has been performed on laboratory animals, in both acute and chronic administration, and the pathological effects on the parenchymal tissues have been investigated. We studied the serum immunological modifications after intraperitoneal administration of the MWCNTs. We did not observe any antigenic reaction; the screening of ANA, anti-ENA, anti-cardiolipin, C-ANCA and P-ANCA was negative. No quantitative modification of immunoglobulins was observed, hence no modification of humoral immunity was documented. We also studied the effects of MWCNTs on the proliferation of three different cell types. MCF-7 showed a significant inhibition of proliferation for all conditions studied, whereas hSMCs demonstrated a reduction of cell growth only for the highest MWCNTs concentrations after 72 h. Also, no growth modification was observed in the Caco-2 cell line. We observed that a low quantity of MWCNTs does not provoke any inflammatory reaction. However, for future medical applications, it is important to realize prosthesis based on MWCNTs, through studying the corresponding implantation effects. Moreover, it has to be emphasized that this investigation does not address, at the moment, the carcinogenicity of MWCNTs, which requires a detailed follow-up investigation on the specific topic. In view of the subsequent and more extensive use of MWCNTs, especially in applications where carbon nanotubes are injected into the human body for drug delivery, as a contrast agent carrying entities for MRI, or as the basic

  8. Carbon nanotubes toxicology and effects on metabolism and immunological modification in vitro and in vivo

    Science.gov (United States)

    Chiaretti, M.; Mazzanti, G.; Bosco, S.; Bellucci, S.; Cucina, A.; LeFoche, F.; Carru, G. A.; Mastrangelo, S.; Di Sotto, A.; Masciangelo, R.; Chiaretti, A. M.; Balasubramanian, C.; DeBellis, G.; Micciulla, F.; Porta, N.; Deriu, G.; Tiberia, A.

    2008-11-01

    The aim of this research is focused on the biological effects of multi wall carbon nanotubes (MWCNTs) on three different human cell types, laboratory animals in vivo, and immunological effects. Large numbers of researchers are directly involved in the handling of nanostructured materials such as MWCNTs and nanoparticles. It is important to assess the potential health risks related to their daily exposure to carbon nanotubes. The administration of sterilized nanosamples has been performed on laboratory animals, in both acute and chronic administration, and the pathological effects on the parenchymal tissues have been investigated. We studied the serum immunological modifications after intraperitoneal administration of the MWCNTs. We did not observe any antigenic reaction; the screening of ANA, anti-ENA, anti-cardiolipin, C-ANCA and P-ANCA was negative. No quantitative modification of immunoglobulins was observed, hence no modification of humoral immunity was documented. We also studied the effects of MWCNTs on the proliferation of three different cell types. MCF-7 showed a significant inhibition of proliferation for all conditions studied, whereas hSMCs demonstrated a reduction of cell growth only for the highest MWCNTs concentrations after 72 h. Also, no growth modification was observed in the Caco-2 cell line. We observed that a low quantity of MWCNTs does not provoke any inflammatory reaction. However, for future medical applications, it is important to realize prosthesis based on MWCNTs, through studying the corresponding implantation effects. Moreover, it has to be emphasized that this investigation does not address, at the moment, the carcinogenicity of MWCNTs, which requires a detailed follow-up investigation on the specific topic. In view of the subsequent and more extensive use of MWCNTs, especially in applications where carbon nanotubes are injected into the human body for drug delivery, as a contrast agent carrying entities for MRI, or as the basic

  9. Intracellular concentrations and metabolism of carbon compounds in tobacco callus cultures: Effects of light and auxin

    Energy Technology Data Exchange (ETDEWEB)

    Lawyer, A.L.; Grady, K.L.; Bassham, J.A.

    1981-10-01

    Callus cultures derived from pith tissue of Nicotiana tobacum were grown on two media either under continuous illumination or in complete darkness. The first medium limited greening ability of callus grown in the light (3 milligrams per liter naphthalene acetic acid, 0.3 milligram per liter 2-isopentenylaminopurine, Murashige and Skoog salts, and 2% sucrose). The second medium encouraged chlorophyll synthesis (greening) though not shoot formation (0.3 milligram per liter naphthalene acetic acid; 0.3 milligrams per liter 2-isopentylaminopurine). To measure intracellular concentrations, calli were grown for 15 days on these standard media containing (U-/sup 14/C)sucrose. The dry weight proportions of the calli (as a fraction of fresh weight) and many metabolite concentrations nearly doubled in light-grown cells compared to dark-grown cells and increase 30 to 40% on low-auxin media relative to high-auxin media. Glutamine concentrations (from 4 to 26 millimolar) were very high, probably due to the NH/sub 3/ content of the media. Proline concentrations were 20-fold higher in calli grown on low-auxin media in the light (green cells), possibly a stress response to high osmotic potentials in these cells. To analyze sucrose metabolism, callus cells were allowed to take up 0.2% (weight per volume) (U-/sup 14/C)sucrose for up to 90 minutes. In callus tissues and in pith sections from stems of tobacco plants, sucrose was primarily metabolized through invertase activity, producing equal amounts of labeling glucose and fructose. Respiration of /sup 14/CO/sub 2/ followed the labeling patterns of tricarboxylic acid cycle intermediates. Photorespiration activity was low.

  10. Changes in photosynthetic carbon metabolism in senescent leaves of chickpea, Cicer arietinum L.

    Directory of Open Access Journals (Sweden)

    Chandrashekhar V. Murumkar

    2014-02-01

    Full Text Available Photosynthetic processes in mature and senescent leaves of chickpea (Cicer arietinum L. have been compared. With age, leaf photosynthetic pigments viz. chlorophyll a, chlorophyll b and carotenoids, and rate of 14°C fixation were considerably affected. Analysis of δ13C, and short term photosynthetic products showed no major change in the path of photosynthetic carbon fixation. Study of long term photosynthetic 14C assimilation revealed that in old senescent leaves, 14C incorporation into organic acid and sugar fractions was enhanced.

  11. Radiohistochemical investigations into the central nervous sialoglycoconjugate metabolism of dormice (Glis glis) in different stages of adaptation

    International Nuclear Information System (INIS)

    Twenty adult dormice (Glis glis, Gliridae) were used to measure seasonal and temperature-related variations of sialoglycoconjugates in the central nervous system. The study had two different aims: On the one hand, biochemical and radiochemical methods of separation were used to investigate 10 cerebral regions for any changes in their individual contents of proteins and protein-bound sialic acids and for alterations in the ganglioside pattern of neurons as well as the time curves plotted for the uptake of a specific ganglioside tracer, 14C-N-Ac-mannosamine, that may possibly arise in response to seasonal and temperature-dependent adaptations. In addition, 32 central cerebral regions were examined for dormice showing different stages of adaptation (winter versus summer) to determine in autoradiograms that percentage share of integrated optical density (IOD), which accounts for the radioactively labelled proportions of TCA/PTA-soluble compounds, sialoglycolipids and sialoglycoproteins plus asialocompounds in the total radioactivity. (orig./ECB)

  12. Persistence of Carbonate Platform Environments in Central Mexico during the Oceanic Anoxic Event 2: impact of the Carribean Plateau?

    Science.gov (United States)

    Bomou, Brahimsamba; Adatte, Thierry; Föllmi, Karl; Arnaud-Vanneau, Annie; Fleitmann, Dominik

    2010-05-01

    The Cenomanian-Turonian Oceanic Anoxic Event 2 is described as an interruption of normal pelagic sediment deposition by several distinct intervals of widespread oceanic anoxia (Schlanger & Jenkyns, 1976; Jenkyns, 1980; Arthur et al., 1990) characterized by black shales deposition coinciding with a positive shift in carbon isotope excursion. Some authors show a relationship between OAEs and massive volcanic events associated with the emplacement of large igneous provinces (LIPs) and sea floor spreading at mid-ocean ridges (Kuroda et al., 2007; Snow et al., 2005). High metal abundance anomalies recorded in pelagic sections (e.g. Pueblo, Colorado) coincide with the massive volcanism that built the Carribean plateau (around 93-94 Ma), associated with the onset of OAE 2 (Snow et al., 2005). Mort et al., (2007) demonstrate that the onset of the OAE 2 was triggered by a short-lived but significant increase in phosphorus burial. The bottom waters became anoxic and switched from being a P sink to a P source, sustaining the productivity in a positive feedback loop. However, the behaviour of phosphorus and trace metals at larger scale, in different paleogeography and paleodepht is still poorly known. The Axaxacualco and Baranca el Cañon sections, located at the Guerrero-Morelos carbonate platform in southern Mexico exhibit a fully correlateable d13C curves. In the distal part of the carbonate platform at Axaxacualco, the maximum d13C positive excursion coincides with oligotrophic carbonate platform environments supported by low concentrations in P and characterized by abundant and diversified benthic microfauna and rudists. The impact of OAE appears may be more significant in the proximal part of the carbonate platform at Barranca, characterized by the deposition of thick laminated microbialites indicative of mesotrophic conditions. The Morelos Carbonate platform with oligotrophic to mesotrophic conditions was persistent throughout the entire OAE2 in Central Mexico despite

  13. Hydrologic characteristics of soils in the High Plains, northern Great Plains, and Central Texas Carbonates Regional Aquifer Systems

    Science.gov (United States)

    Dugan, Jack T.; Hobbs, Ryne D.; Ihm, Laurie A.

    1990-01-01

    Certain physical characteristics of soils, including permeability, available water capacity, thickness, and topographic position, have a measurable effect on the hydrology of an area. These characteristics control the rate at which precipitation infiltrates or is transmitted through the soil, and thus they have an important role in determining the rates of actual evapotranspiration (consumptive water use), groundwater recharge, and surface runoff. In studies of groundwater hydrology, it is useful to differentiate soils spatially according to their physical characteristics and to assign values that indicate their hydrologic responses.The principal purpose of this report is to describe the relation between the hydrologic characteristics of the soils in the study area and those environmental factors that affect the development and distribution of the soils. This objective will be achieved by (1) defining both qualitatively and quantitatively those soil characteristics that affect hydrology, and (2) classifying and delineating the boundaries of the soils in the study area according to these hydrologic characteristics.The study area includes the High Plains, Northern Great Plains, the Central Texas Carbonates, and parts of the Central Midwest Regional Aquifer Systems as described by the U.S. Geological Survey Regional Aquifer-System Analysis (RASA) Program (Sun, 1986, p.5and Sun, personal commun., June 1985) and shown in figures 1 through 5. The spatial patterns of the soils classified according to their quantifiable hydrologic characteristics will subsequently serve as an integral component in the analysis of actual evapotranspiration (consumptive water use), consumptive irrigation requirements, and potential ground-water recharge of the study area.The classification system used to describe the soils in this report is compatible with that of Dugan (1986). Dugan described the same characteristics of soils that are immediately underlain by principal aquifers of

  14. Evidence and future scenarios of a low-carbon energy transition in Central America: a case study in Nicaragua

    Science.gov (United States)

    Barido, Diego Ponce de Leon; Johnston, Josiah; Moncada, Maria V.; Callaway, Duncan; Kammen, Daniel M.

    2015-10-01

    The global carbon emissions budget over the next decades depends critically on the choices made by fast-growing emerging economies. Few studies exist, however, that develop country-specific energy system integration insights that can inform emerging economies in this decision-making process. High spatial- and temporal-resolution power system planning is central to evaluating decarbonization scenarios, but obtaining the required data and models can be cost prohibitive, especially for researchers in low, lower-middle income economies. Here, we use Nicaragua as a case study to highlight the importance of high-resolution open access data and modeling platforms to evaluate fuel-switching strategies and their resulting cost of power under realistic technology, policy, and cost scenarios (2014-2030). Our results suggest that Nicaragua could cost-effectively achieve a low-carbon grid (≥80%, based on non-large hydro renewable energy generation) by 2030 while also pursuing multiple development objectives. Regional cooperation (balancing) enables the highest wind and solar generation (18% and 3% by 2030, respectively), at the least cost (US127 MWh-1). Potentially risky resources (geothermal and hydropower) raise system costs but do not significantly hinder decarbonization. Oil price sensitivity scenarios suggest renewable energy to be a more cost-effective long-term investment than fuel oil, even under the assumption of prevailing cheap oil prices. Nicaragua’s options illustrate the opportunities and challenges of power system decarbonization for emerging economies, and the key role that open access data and modeling platforms can play in helping develop low-carbon transition pathways.

  15. Sedimentology of a Mid-Late Ordovician carbonate mud-mound complex from the Kathmandu nappe in Central Nepal

    Science.gov (United States)

    Pas, Damien; Da Silva, Anne-Christine; Dhital, Megh Raj; Boulvain, Frédéric

    2011-08-01

    This sedimentological study of the Godavari quarry is the first relating to the Palaeozoic Tethyan sedimentary rocks of the Katmandu nappe (Central Nepal). Sedimentological analyses led to the identification of six microfacies belonging to a large carbonate mud-mound complex, which can be divided into mound, flank and off-mound main depositional settings. Identification of two dasycladaceans ( Dasyporell a cf. silurica ( Stolley, 1893) and Vermiporella sp.) in the mound facies gives a Mid-Late Ordovician age to this newly discovered Godavari carbonate mud-mound, which makes this mound one of the oldest ever described in the Asian continent. The mound microfacies are characterized by a high micritic content, the presence of stromatactis and the prevalence of red coloured sediments (the red pigmentation probably being related to organic precipitation of iron). The flank microfacies are characterized by a higher crinoid and argillaceous content and the presence of bio- and lithoclasts concentrated in argillaceous lenses. Finally, the off-mound microfacies show very few bioclasts and a high argillaceous content. Palaeoenvionmental interpretation of microfacies, in terms of bathymetry, leads us to infer that the Godavari mud-mound started to grow in a deep environment setting below the photic and wave action zones and that it evolved to occupy a location below the fair weather wave base. Cementation of cavities within the mound facies underlines a typical transition from a marine to a burial diagenetic environment characterized by: (1) a radiaxial non luminescent feroan calcite cement (marine) showing a bright orange luminescent band in its middle part; (2) a bright zoned orange fringe of automorphic feroan calcite (meteoric phreatic); (3) a dull orange xenomorphic feroan calcite cement in the centre of cavities (burial) and (4) a saddle dolomite within the centre of larger cavities. The faunal assemblage (diversity and relative proportion) of the Godavari mound facies

  16. Hybrid dynamic modeling of Escherichia coli central metabolic network combining Michaelis–Menten and approximate kinetic equations

    DEFF Research Database (Denmark)

    Costa, Rafael S.; Machado, Daniel; Rocha, Isabel;

    2010-01-01

    The construction of dynamic metabolic models at reaction network level requires the use of mechanistic enzymatic rate equations that comprise a large number of parameters. The lack of knowledge on these equations and the difficulty in the experimental identification of their associated parameters...... using the hybrid model composed of Michaelis–Menten and the approximate lin-log kinetics indicate that this is a possible suitable approach to model complex large-scale networks where the exact rate laws are unknown.......The construction of dynamic metabolic models at reaction network level requires the use of mechanistic enzymatic rate equations that comprise a large number of parameters. The lack of knowledge on these equations and the difficulty in the experimental identification of their associated parameters......, represent nowadays the limiting factor in the construction of such models. In this study, we compare four alternative modeling approaches based on Michaelis–Menten kinetics for the bi-molecular reactions and different types of simplified rate equations for the remaining reactions (generalized mass action...

  17. Potato tuber expression of Arabidopsis WRINKLED1 increase triacylglycerol and membrane lipids while affecting central carbohydrate metabolism.

    Science.gov (United States)

    Hofvander, Per; Ischebeck, Till; Turesson, Helle; Kushwaha, Sandeep K; Feussner, Ivo; Carlsson, Anders S; Andersson, Mariette

    2016-09-01

    Tuber and root crops virtually exclusively accumulate storage products in the form of carbohydrates. An exception is yellow nutsedge (Cyperus esculentus) in which tubers have the capacity to store starch and triacylglycerols (TAG) in roughly equal amounts. This suggests that a tuber crop can efficiently handle accumulation of energy dense oil. From a nutritional as well as economic aspect, it would be of interest to utilize the high yield capacity of tuber or root crops for oil accumulation similar to yellow nutsedge. The transcription factor WRINKLED1 from Arabidopsis thaliana, which in seed embryos induce fatty acid synthesis, has been shown to be a major factor for oil accumulation. WRINKLED1 was expressed in potato (Solanum tuberosum) tubers to explore whether this factor could impact tuber metabolism. This study shows that a WRINKLED1 transcription factor could induce triacylglycerol accumulation in tubers of transformed potato plants grown in field (up to 12 nmol TAG/mg dry weight, 1% of dry weight) together with a large increase in polar membrane lipids. The changes in metabolism further affected starch accumulation and composition concomitant with massive increases in sugar content. PMID:26914183

  18. Central nervous determination of food storage--a daily switch from conservation to expenditure: implications for the metabolic syndrome.

    Science.gov (United States)

    Kreier, Felix; Kalsbeek, Andries; Ruiter, Marieke; Yilmaz, Ajda; Romijn, Johannes A; Sauerwein, Hans P; Fliers, Eric; Buijs, Ruud M

    2003-11-01

    Here, we present a neuroendocrine concept to review the circularly interacting energy homeostasis system between brain and body. Body-brain interaction is circular because the brain immediately integrates an input to an output, and because part of this response may be that the brain modulates the sensitivity of this perception. First, we describe how the brain senses the body through neurons and blood-borne factors. Direct neuronal connections report the state of various organs. In addition, humoral factors are perceived by the blood-brain barrier and circumventricular organs. We describe how circulating energy carriers are sensed and what signals reach the brain during food intake, exercise and an immune response. We describe that the brain regulates the homeostatic process at two fundamentally different levels during the active and inactive states. The unbalanced output of the brain in the metabolic syndrome is discussed in relation with such circadian rhythms and with regional activity of the autonomic nervous system. In line with the above, we suggest a new approach for the diagnosis and therapy of the metabolic syndrome.

  19. Fluxes of nitrous oxide and carbon dioxide over four potential biofuel crops in Central Illinois

    Science.gov (United States)

    Zeri, M.; Hickman, G. C.; Bernacchi, C.

    2009-12-01

    Nitrous oxide (N2O) and carbon dioxide (CO2) are important greenhouse gases that contribute to global climate change. Agriculture is a significant source of N2O to the atmosphere due to the use of nitrogen-based fertilizers. Fluxes of N2O and CO2 are measured using the flux-gradient technique over four different crops at the Energy Farm, a University of Illinois research facility in Urbana, Illinois. Measurements started in June of 2009 and are part of a project that aims to assess the impacts of potential biofuel crops on the carbon, water and nitrogen cycles. The species chosen are Maize (Zea mays), Miscanthus (Miscanthus x giganteus), Switchgrass (Panicum virgatum) and Prairie (a mix of several native species). The choice of species was based on their potential for the production of second-generation biofuels, i.e., fuels derived from the decomposition of the cellulosic material in the plant biomass. The use of corn residue for cellulosic biofuels might impact the carbon cycle through the reduction of soil organic content. Miscanthus is a perennial grass with great potential for biomass production. However, the total water used during the growing season and its water use efficiency might impose limits on the regions where this biofuel crop can be sustainably planted on a large scale. Switchgrass and the prairie species are less productive but might be suited for being well adapted and easy to establish. This study is the first side-by-side comparison of fluxes of N2O for these agro-ecosystems. The measurements are performed at micrometeorological towers placed at the center of 4 ha plots. The air is sampled at two heights over the vegetation and is analyzed in a tunable diode laser (TDL) installed nearby. A valve system cycles the TDL measurements trough all the intakes in the plots. The fluxes are calculated using the flux-gradient method, which requires the knowledge of the scalar vertical gradient as well as of the friction velocity (u*) and the Monin

  20. Simulation of Flux Distribution in Central Metabolism of Saccharomyces cerevisiae by Hybridized Genetic Algorithm%杂合基因算法在酵母中间代谢途径代谢通量分析中的应用

    Institute of Scientific and Technical Information of China (English)

    张慧敏; 姚善泾

    2007-01-01

    A scheme of investigating the intracellular metabolic fluxes in central metabolism of Saccharomyces cerevisiae based on isotope model and tracer experiment was developed. The metabolic model applied in this study includes the Embden-Meyerhof-Parnas pathway, the pentose phosphate pathway, the tricarboxylic acid cycle, CO2 anaplerotic reactions, ethanol and acetate formation, and pathways involved in amino acid synthesis. The approach of hybridized genetic algorithm combined with the sequential simplex technique was used to optimize a quadratic error function without the requirement of the information on the partial derivatives. The impact of some key parameters on the algorithm was studied. This approach was proved to be rapid and numerically stable in the analysis of the central metabolism of S.cerevisiae.

  1. METABOLIC ENGINEERING TO DEVELOP A PATHWAY FOR THE SELECTIVE CLEAVAGE OF CARBON-NITROGEN BONDS

    Energy Technology Data Exchange (ETDEWEB)

    John J. Kilbane II

    2004-10-01

    The objective of the project is to develop biochemical pathways for the selective cleavage of C-N bonds in molecules found in petroleum. The initial phase of the project was focused on the isolation or development of an enzyme capable of cleaving the C-N bond in aromatic amides, specifically 2-aminobiphenyl. The objective of the second phase of the research will be to construct a biochemical pathway for the selective removal of nitrogen from carbazole by combining the carA genes from Sphingomonas sp. GTIN11 with the gene(s) encoding an appropriate deaminase. The objective of the final phase of the project will be to develop derivative C-N bond cleaving enzymes that have broader substrate ranges and to demonstrate the use of such strains to selectively remove nitrogen from petroleum. During the first year of the project (October, 2002-September, 2003) enrichment culture experiments resulted in the isolation of microbial cultures that utilize aromatic amides as sole nitrogen sources, several amidase genes were cloned and were included in directed evolution experiments to obtain derivatives that can cleave C-N bonds in aromatic amides, and the carA genes from Sphingomonas sp. GTIN11, and Pseudomonas resinovorans CA10 were cloned in vectors capable of replicating in Escherichia coli. During the second year of the project (October, 2003-September, 2004) enrichment culture experiments succeeded in isolating a mixed bacterial culture that can utilize 2-aminobiphenyl as a sole nitrogen source, directed evolution experiments were focused on the aniline dioxygenase enzyme that is capable of deaminating aniline, and expression vectors were constructed to enable the expression of genes encoding C-N bond cleaving enzymes in Rhodococcus hosts. The construction of a new metabolic pathway to selectively remove nitrogen from carbazole and other molecules typically found in petroleum should lead to the development of a process to improve oil refinery efficiency by reducing the

  2. Reservoir Potential of Silurian Carbonate Mud Mounds in the Southern Sichuan Basin, Central China

    Institute of Scientific and Technical Information of China (English)

    ZHAO Wenzhi; YANG Xiaoping; Steve KERSHAW; ZHANG Baomin

    2006-01-01

    Lower Silurian mud mounds of the Shinuilan Formation, located in the southern Sichuan Basin, China, have developed in open shelf settings in deeper water than shallow-water reef-bearing limestones that occur in the region. An integration of the outcrop, drill data and seismic profiles show that contemporaneous faults have controlled the boundary and distribution of the sedimentary facies of Lower Silurian rocks in the southern Sichuan Basin. Mounds appear to have developed in the topographic lows formed by synsedimentary faulting, on the shelf of the Yangtze Platform. Average mound thickness is 20 m, maximum 35 m. Mounds are composed mainly of micrite, possibly microbially bound, and are overlain by shales. Mound tops are preferentially dolomitized, with the Mg2+ source probably from the clay content of the mound-top carbonate. Microfacies analysis and reconstruction of the diagenetic history reveal that the mound tops have higher porosity, and are gas targets; in contrast, mound cores and limbs show pores filled by three generations of calcite cement, and therefore have a low gas potential.

  3. Algal C-14 and total carbon metabolisms 2. Experimental observations with the diatom Skeletonema costatum

    DEFF Research Database (Denmark)

    Williams, P.J.L.; Robinson, C.; Søndergaard, M.;

    1996-01-01

    of 2-3), C-14 uptake into the particulate plus the dissolved fractions approximated to net photosynthesis. Rate constants derived from the chemically determined changes were used to parameterize models that accounted for the respiration of photosynthetic products and for the recycling of respiratory CO......Three sets of comparisons of net and gross inorganic carbon assimilation and C-14 uptake were made with an axenic culture of Skeletonema costatum. The comparisons showed that in the physiological window studied (10-20% of the intrinsic generation time and gross photosynthesis/respiration ratios......2. The conclusion drawn was that over the time scale studied, the C-14 technique was measuring net photosynthesis, consistent with essentially 100% recycling of respiratory CO2. The study has shown that we now possess the basis to make a rigorous analysis of net, gross CO2 fixation and net C-14...

  4. Using Eddy Covariance Sensors to Quantify Carbon Metabolism of Peatlands: A Case Study in Turkey

    OpenAIRE

    Can Ertekin; Guler Aslan; Fatih Evrendilek; Nusret Karakaya

    2011-01-01

    Net ecosystem exchange (NEE) of carbon dioxide (CO2) was measured in a cool temperate peatland in northwestern Turkey on a continuous basis using eddy covariance (EC) sensors and multiple (non-)linear regression-M(N)LR-models. Our results showed that hourly NEE varied between −1.26 and 1.06 mg CO2 m−2 s−1, with a mean value of 0.11 mg CO2 m−2 s−1. Nighttime ecosystem respiration (R E) was on average measured as 0.23 ± 0.09 mg CO2 m−2 s−1. Two best-fit M(N)LR models estimated daytime R E as 0....

  5. The Stable Level of Glutamine synthetase 2 Plays an Important Role in Rice Growth and in Carbon-Nitrogen Metabolic Balance.

    Science.gov (United States)

    Bao, Aili; Zhao, Zhuqing; Ding, Guangda; Shi, Lei; Xu, Fangsen; Cai, Hongmei

    2015-06-04

    Glutamine synthetase 2 (GS2) is a key enzyme involved in the ammonium metabolism in plant leaves. In our previous study, we obtained GS2-cosuppressed plants, which displayed a normal growth phenotype at the seedling stage, while at the tillering stage they showed a chlorosis phenotype. In this study, to investigate the chlorosis mechanism, we systematically analyzed the plant growth, carbon-nitrogen metabolism and gene expressions between the GS2-cosuppressed rice and wild-type plants. The results revealed that the GS2-cosuppressed plants exhibited a poor plant growth phenotype and a poor nitrogen transport ability, which led to nitrogen accumulation and a decline in the carbon/nitrogen ratio in the stems. Interestingly, there was a higher concentration of soluble proteins and a lower concentration of carbohydrates in the GS2-cosuppressed plants at the seedling stage, while a contrasting result was displayed at the tillering stage. The analysis of the metabolic profile showed a significant increase of sugars and organic acids. Additionally, gene expression patterns were different in root and leaf of GS2-cosuppressed plants between the seedling and tillering stage. These results indicated the important role of a stable level of GS2 transcription during normal rice development and the importance of the carbon-nitrogen metabolic balance in rice growth.

  6. Transcriptional regulation of respiration in yeast metabolizing differently repressive carbon substrates

    Directory of Open Access Journals (Sweden)

    Fendt Sarah-Maria

    2010-02-01

    Full Text Available Abstract Background Depending on the carbon source, Saccharomyces cerevisiae displays various degrees of respiration. These range from complete respiration as in the case of ethanol, to almost complete fermentation, and thus very low degrees of respiration on glucose. While many key regulators are known for these extreme cases, we focus here on regulators that are relevant at intermediate levels of respiration. Results We address this question by linking the functional degree of respiration to transcriptional regulation via enzyme abundances. Specifically, we investigated aerobic batch cultures with the differently repressive carbon sources glucose, mannose, galactose and pyruvate. Based on 13C flux analysis, we found that the respiratory contribution to cellular energy production was largely absent on glucose and mannose, intermediate on galactose and highest on pyruvate. In vivo abundances of 40 respiratory enzymes were quantified by GFP-fusions under each condition. During growth on the partly and fully respired substrates galactose and pyruvate, several TCA cycle and respiratory chain enzymes were significantly up-regulated. From these enzyme levels and the known regulatory network structure, we determined the probability for a given transcription factor to cause the coordinated expression changes. The most probable transcription factors to regulate the different degrees of respiration were Gcr1p, Cat8p, the Rtg-proteins and the Hap-complex. For the latter three ones we confirmed their importance for respiration by quantifying the degree of respiration and biomass yields in the corresponding deletion strains. Conclusions Cat8p is required for wild-type like respiration, independent of its known activation of gluconeogenic genes. The Rtg-proteins and the Hap-complex are essential for wild-type like respiration under partially respiratory conditions. Under fully respiratory conditions, the Hap-complex, but not the Rtg-proteins are essential

  7. Metabolic Engineering to Develop a Pathway for the Selective Cleavage of Carbon-Nitrogen Bonds

    Energy Technology Data Exchange (ETDEWEB)

    John J. Kilbane II

    2005-10-01

    The objective of the project is to develop a biochemical pathway for the selective cleavage of C-N bonds in molecules found in petroleum. Specifically a novel biochemical pathway will be developed for the selective cleavage of C-N bonds in carbazole. The cleavage of the first C-N bond in carbazole is accomplished by the enzyme carbazole dioxygenase, that catalyzes the conversion of carbazole to 2-aminobiphenyl-2,3-diol. The genes encoding carbazole dioxygenase were cloned from Sphingomonas sp. GTIN11 and from Pseudomonas resinovorans CA10. The selective cleavage of the second C-N bond has been challenging, and efforts to overcome that challenge have been the focus of recent research in this project. Enrichment culture experiments succeeded in isolating bacterial cultures that can metabolize 2-aminobiphenyl, but no enzyme capable of selectively cleaving the C-N bond in 2-aminobiphenyl has been identified. Aniline is very similar to the structure of 2-aminobiphenyl and aniline dioxygenase catalyzes the conversion of aniline to catechol and ammonia. For the remainder of the project the emphasis of research will be to simultaneously express the genes for carbazole dioxygenase and for aniline dioxygenase in the same bacterial host and then to select for derivative cultures capable of using carbazole as the sole source of nitrogen.

  8. Patterns of Carbon Partitioning in Leaves of Crassulacean Acid Metabolism Species during Deacidification.

    Science.gov (United States)

    Christopher, J. T.; Holtum, JAM.

    1996-09-01

    Carbohydrates stored during deacidification in the light were examined in 11 Crassulacean acid metabolism (CAM) species from widely separated taxa grown under uniform conditions. The hypothesis that NAD(P) malic enzyme CAM species store chloroplastic starch and glucans, and phosphoenolpyruvate carboxykinase species store extrachloroplastic sugars or polymers was disproved. Of the six malic enzyme species examined, Kalanchoe tubiflora, Kalanchoe pinnata, Kalanchoe daigremontiana, and Vanilla planifolia stored mainly starch. Sansevieria hahnii stored sucrose and Agave guadalajarana did not store starch, glucose, fructose, or sucrose. Of the five phosphoenolpyruvate carboxykinase species investigated, Ananus comosus stored extrachloroplastic carbohydrate, but Stapelia gigantea, Hoya carnosa, and Portea petropolitana stored starch, whereas Aloe vera stored both starch and glucose. Within families, the major decarboxylase was common for all species examined, whereas storage carbohydrate could differ both between and within genera. In the Bromeliaceae, A. comosus stored mainly fructose, but P. petropolitana stored starch. In the genus Aloe, A. vera stored starch and glucose, but A. arborescens is known to store a galactomannan polymer. We postulate that the observed variation in carbohydrate partitioning between CAM species is the result of two principal components: (a) constraints imposed by the CAM syndrome itself, and (b) diversity in biochemistry resulting from different evolutionary histories. PMID:12226397

  9. Cross-Talk between Carbon Metabolism and the DNA Damage Response in S. cerevisiae

    Directory of Open Access Journals (Sweden)

    Kobi J. Simpson-Lavy

    2015-09-01

    Full Text Available Yeast cells with DNA damage avoid respiration, presumably because products of oxidative metabolism can be harmful to DNA. We show that DNA damage inhibits the activity of the Snf1 (AMP-activated protein kinase (AMPK, which activates expression of genes required for respiration. Glucose and DNA damage upregulate SUMOylation of Snf1, catalyzed by the SUMO E3 ligase Mms21, which inhibits SNF1 activity. The DNA damage checkpoint kinases Mec1/ATR and Tel1/ATM, as well as the nutrient-sensing protein kinase A (PKA, regulate Mms21 activity toward Snf1. Mec1 and Tel1 are required for two SNF1-regulated processes—glucose sensing and ADH2 gene expression—even without exogenous genotoxic stress. Our results imply that inhibition of Snf1 by SUMOylation is a mechanism by which cells lower their respiration in response to DNA damage. This raises the possibility that activation of DNA damage checkpoint mechanisms could contribute to aerobic fermentation (Warburg effect, a hallmark of cancer cells.

  10. Alcohol-induced One-carbon Metabolism Impairment Promotes Dysfunction of DNA Base Excision Repair in Adult Brain*

    Science.gov (United States)

    Fowler, Anna-Kate; Hewetson, Aveline; Agrawal, Rajiv G.; Dagda, Marisela; Dagda, Raul; Moaddel, Ruin; Balbo, Silvia; Sanghvi, Mitesh; Chen, Yukun; Hogue, Ryan J.; Bergeson, Susan E.; Henderson, George I.; Kruman, Inna I.

    2012-01-01

    The brain is one of the major targets of chronic alcohol abuse. Yet the fundamental mechanisms underlying alcohol-mediated brain damage remain unclear. The products of alcohol metabolism cause DNA damage, which in conditions of DNA repair dysfunction leads to genomic instability and neural death. We propose that one-carbon metabolism (OCM) impairment associated with long term chronic ethanol intake is a key factor in ethanol-induced neurotoxicity, because OCM provides cells with DNA precursors for DNA repair and methyl groups for DNA methylation, both critical for genomic stability. Using histological (immunohistochemistry and stereological counting) and biochemical assays, we show that 3-week chronic exposure of adult mice to 5% ethanol (Lieber-Decarli diet) results in increased DNA damage, reduced DNA repair, and neuronal death in the brain. These were concomitant with compromised OCM, as evidenced by elevated homocysteine, a marker of OCM dysfunction. We conclude that OCM dysfunction plays a causal role in alcohol-induced genomic instability in the brain because OCM status determines the alcohol effect on DNA damage/repair and genomic stability. Short ethanol exposure, which did not disturb OCM, also did not affect the response to DNA damage, whereas additional OCM disturbance induced by deficiency in a key OCM enzyme, methylenetetrahydrofolate reductase (MTHFR) in Mthfr+/− mice, exaggerated the ethanol effect on DNA repair. Thus, the impact of long term ethanol exposure on DNA repair and genomic stability in the brain results from OCM dysfunction, and MTHFR mutations such as Mthfr 677C→T, common in human population, may exaggerate the adverse effects of ethanol on the brain. PMID:23118224

  11. Carbonate extraction process for the metabolic, isozymic and proteomic profiling of rose-scented geranium (Pelargonium sp.), a hyper-acidic plant.

    Science.gov (United States)

    Sangwan, Rajender Singh; Sangwan, Neelam Singh; Sharma, Pankaj Kumar; Chaurasiya, Narayan Das; Mishra, Siddhartha Kumar; Tyagi, Bali Ram; Srivastava, Avdhesh Kumar

    2008-01-01

    Rose-scented geranium (Pelargonium sp.) is a valuable monoterpene-yielding plant. It has been well characterised phytochemically through the isolation of >270 secondary metabolites, however, there is hardly any biochemical or metabolic information concerning this plant. Initial attempts to investigate its metabolism failed to produce any enzyme activity in the tissue extracts prepared in routine extraction buffers owing to the intrinsic properties of the tissue matrix. It was recognised that cellular hyper-acidity (cell sap pH approximately 3.0) gave rise to very low protein levels in the extracts, thus prohibiting detection of activities of even primary metabolic enzymes that are usually abundantly present in plants. Tissue extraction in Tris solution without pH adjustment (as used for studies involving citrus and banana) led to little or no improvement. Therefore, a novel approach using sodium carbonate solution as an efficient extraction system for enzymes and proteins from the plant was studied. Functionality of the carbonate extraction has been demonstrated through its effectiveness, a several-fold superior performance, in yielding protein, monitoring primary metabolism and secondary metabolic enzymes, and isozymic and polypeptide profiling. The process may also be helpful in the reliable analysis of other acidic plant tissues.

  12. Effects of sublethal fenitrothion ingestion on cholinesterase inhibition, standard metabolism, thermal preference, and prey-capture ability in the Australian central bearded dragon (Pogona vitticeps, Agamidae).

    Science.gov (United States)

    Bain, David; Buttemer, William A; Astheimer, Lee; Fildes, Karen; Hooper, Michael J

    2004-01-01

    The central bearded dragon (Pogona vitticeps) is a medium-sized lizard that is common in semiarid habitats in Australia and that potentially is at risk of fenitrothion exposure from use of the chemical in plague locust control. We examined the effects of single sublethal doses of this organophosphate (OP; low dose = 2.0 mg/kg; high dose = 20 mg/kg; control = vehicle alone) on lizard thermal preference, standard metabolic rate, and prey-capture ability. We also measured activities of plasma total cholinesterase (ChE) and acetylcholinesterase before and at 0, 2, 8, 24, 120, and 504 h after OP dosing. Predose plasma total ChE activity differed significantly between sexes and averaged 0.66 +/- 0.06 and 0.45 +/- 0.06 micromol/min/ml for males and females, respectively. Approximately 75% of total ChE activity was attributable to butyrylcholinesterase. Peak ChE inhibition reached 19% 2 h after OP ingestion in the low-dose group, and 68% 8 h after ingestion in high-dose animals. Neither OP doses significantly affected diurnal body temperature, standard metabolic rate, or feeding rate. Plasma total ChE levels remained substantially depressed up to 21 d after dosing in the high-dose group, making this species a useful long-term biomonitor of OP exposure in its habitat. PMID:14768874

  13. DISTRIBUTION OF ORGANIC CARBON IN DIFFERENT SOIL FRACTIONS IN ECOSYSTEMS OF CENTRAL AMAZONIA

    Directory of Open Access Journals (Sweden)

    Jean Dalmo de Oliveira Marques

    2015-02-01

    Full Text Available Organic matter plays an important role in many soil properties, and for that reason it is necessary to identify management systems which maintain or increase its concentrations. The aim of the present study was to determine the quality and quantity of organic C in different compartments of the soil fraction in different Amazonian ecosystems. The soil organic matter (FSOM was fractionated and soil C stocks were estimated in primary forest (PF, pasture (P, secondary succession (SS and an agroforestry system (AFS. Samples were collected at the depths 0-5, 5-10, 10-20, 20-40, 40-60, 60-80, 80-100, 100-160, and 160-200 cm. Densimetric and particle size analysis methods were used for FSOM, obtaining the following fractions: FLF (free light fraction, IALF (intra-aggregate light fraction, F-sand (sand fraction, F-clay (clay fraction and F-silt (silt fraction. The 0-5 cm layer contains 60 % of soil C, which is associated with the FLF. The F-clay was responsible for 70 % of C retained in the 0-200 cm depth. There was a 12.7 g kg-1 C gain in the FLF from PF to SS, and a 4.4 g kg-1 C gain from PF to AFS, showing that SS and AFS areas recover soil organic C, constituting feasible C-recovery alternatives for degraded and intensively farmed soils in Amazonia. The greatest total stocks of carbon in soil fractions were, in decreasing order: (101.3 Mg ha-1 of C - AFS > (98.4 Mg ha-1 of C - FP > (92.9 Mg ha-1 of C - SS > (64.0 Mg ha-1 of C - P. The forms of land use in the Amazon influence C distribution in soil fractions, resulting in short- or long-term changes.

  14. Export of dissolved organic carbon from the Penobscot River basin in north-central Maine

    Science.gov (United States)

    Huntington, Thomas G.; Aiken, George R.

    2013-01-01

    Dissolved organic carbon (DOC) flux from the Penobscot River and its major tributaries in Maine was determined using continuous discharge measurements, discrete water sampling, and the LOADEST regression software. The average daily flux during 2004–2007 was 71 kg C ha−1 yr−1 (392 Mt C d−1), an amount larger than measured in most northern temperate and boreal rivers. Distinct seasonal variation was observed in the relation between concentration and discharge (C–Q). During June through December (summer/fall), there was a relatively steep positive C–Q relation where concentration increased by a factor of 2–3 over the approximately 20-fold range of observed stream discharge for the Penobscot River near Eddington, Maine. In contrast, during January through May (winter/spring), DOC concentration did not increase with increasing discharge. In addition, we observed a major shift in the C–Q between 2004–2005 and 2006–2007, apparently resulting from unprecedented rainfall, runoff, and soil flushing beginning in late fall 2005. The relative contribution to the total Penobscot River basin DOC flux from each tributary varied dramatically by season, reflecting the role of large regulated reservoirs in certain basins. DOC concentration and flux per unit watershed area were highest in tributaries containing the largest areas in palustrine wetlands. Tributary DOC concentration and flux was positively correlated to percentage wetland area. Climatic or environmental changes that influence the magnitude or timing of river discharge or the abundance of wetlands will likely affect the export of DOC to the near-coastal ocean.

  15. Central acylated ghrelin improves memory function and hippocampal AMPK activation and partly reverses the impairment of energy and glucose metabolism in rats infused with β-amyloid.

    Science.gov (United States)

    Kang, Suna; Moon, Na Rang; Kim, Da Sol; Kim, Sung Hoon; Park, Sunmin

    2015-09-01

    Ghrelin is a gastric hormone released during the fasting state that targets the hypothalamus where it induces hunger; however, emerging evidence suggests it may also affect memory function. We examined the effect of central acylated-ghrelin and DES-acetylated ghrelin (native ghrelin) on memory function and glucose metabolism in an experimentally induced Alzheimer's disease (AD) rat model. AD rats were divided into 3 groups and Non-AD rats were used as a normal-control group. Each rat in the AD groups had intracerebroventricular (ICV) infusion of β-amyloid (25-35; 16.8nmol/day) into the lateral ventricle for 3 days, and then the pumps were changed to infuse either acylated-ghrelin (0.2nmol/h; AD-G), DES-acylated ghrelin (0.2nmol/h; AD-DES-G), or saline (control; AD-C) for 3 weeks. The Non-AD group had ICV infusion of β-amyloid (35-25) which does not deposit in the hippocampus. During the next 3 weeks memory function, food intake, body weight gain, body fat composition, and glucose metabolism were measured. AD-C exhibited greater β-amyloid deposition compared to Non-AD-C, and AD-G suppressed the increased β-amyloid deposition and potentiated the phosphorylation AMPK. In addition, AD-G increased the phosphorylation GSK and decreased the phosphorylation of Tau in comparison to AD-C and AD-DES-G. Cognitive function, measured by passive avoidance and water maze tests, was much lower in AD-C than Non-AD-C whereas AD-G but not AD-DES-G prevented the decrease (pintermittent fasting to facilitate sustained elevations of acyl-ghrelin should be investigated for cognitive and metabolic benefits, especially in person with early symptoms of memory impairment. PMID:26188171

  16. Impact of predicted changes in rainfall and atmospheric carbon dioxide on maize and wheat yeilds in the Central Rift Valley of Ethiopia

    NARCIS (Netherlands)

    Muluneh, A.; Biazin, B.; Stroosnijder, L.; Bewket, W.; Keesstra, S.D.

    2015-01-01

    This study assesses potential impacts of climate change on maize and wheat yields in the Central Rift Valley (CRV) of Ethiopia. We considered effects of elevated atmospheric carbon dioxide (CO2) and changes in rainfall during the main (Kiremt) and the short (Belg) rainfall cropping seasons during th

  17. Using Eddy Covariance Sensors to Quantify Carbon Metabolism of Peatlands: A Case Study in Turkey

    Directory of Open Access Journals (Sweden)

    Can Ertekin

    2011-01-01

    Full Text Available Net ecosystem exchange (NEE of carbon dioxide (CO2 was measured in a cool temperate peatland in northwestern Turkey on a continuous basis using eddy covariance (EC sensors and multiple (non-linear regression-M(NLR-models. Our results showed that hourly NEE varied between −1.26 and 1.06 mg CO2 m−2 s−1, with a mean value of 0.11 mg CO2 m−2 s−1. Nighttime ecosystem respiration (RE was on average measured as 0.23 ± 0.09 mg CO2 m−2 s−1. Two best-fit M(NLR models estimated daytime RE as 0.64 ± 0.31 and 0.24 ± 0.05 mg CO2 m−2 s−1. Total RE as the sum of nighttime and daytime RE ranged from 0.47 to 0.87 mg CO2 m−2 s−1, thus yielding estimates of gross primary productivity (GPP at −0.35 ± 0.18 and −0.74 ± 0.43 mg CO2 m−2 s−1. Use of EC sensors and M(NLR models is one of the most direct ways to quantify turbulent CO2 exchanges among the soil, vegetation and atmosphere within the atmospheric boundary layer, as well as source and sink behaviors of ecosystems.

  18. {sup 210}Pb dating of sediments from the central and northern Adriatic Sea: deposition and preservation of sedimentary organic carbon

    Energy Technology Data Exchange (ETDEWEB)

    Hamilton, T. F., LLNL

    1998-04-01

    Lead-210 ({sup 21O}Pb) and organic C depth distribution profiles in sediments from the northern and central Adriatic Sea were measured as part of the EEC funded project on Eutrophic Limits of the Northern Adriatic (ELNA). {sup 210}Pb derived mass-accumulation rates decrease southward from between 0.15 and 0.2 g cm{sup -2}y{sup -1} close to the Po River outflow (> 24 m, water depth) to less than 0.04 g cm{sup -2}y{sup -1} in the Jabuka Pit (246 m, water depth) in the central Adriatic Sea. The mass- accumulation rates obtained in the Jabuka Pit correspond to mean sedimentation rates of about 0.03 cm y{sup -1} (ref. porosity = 0.5) and fall between 5 to 20 times lower than rates found for north Adriatic shelf cores. Estimated sedimentation rates are considered as upper limits because of the possible effects of bioturbation and physical disturbance on the {sup 21O}Pb sedimentary record but are consistent with data from previous work. Rates of sediment accumulation and carbon burial appear to be strongly influenced by the transport of fluvial materials from land and transport of fine-grained particles. First-order estimates of organic C burial rates into surface sediment ranged from 1 to 0.028 mMol cm{sup -2}y{sup -1} between the Po delta and the Jabuka Pit regions, respectively. We estimate that a maximum of 50% of organic C preserved in surface sediment may be derived from biological production in the overlying water column.

  19. Decomposition, nitrogen and carbon mineralization from food and cover crop residues in the central plateau of Haiti.

    Science.gov (United States)

    Lynch, M J; Mulvaney, M J; Hodges, S C; Thompson, T L; Thomason, W E

    2016-01-01

    Cover crops are a major focus of conservation agriculture efforts because they can provide soil cover and increase nutrient availability after their mineralization in cropping systems. To evaluate the effect of residue type and placement on rate of decomposition and carbon (C) and nitrogen (N) mineralization, residues from two food crops, maize (Zea mays L.) and common bean (Phaseolus vulgaris L.), and two promising cover crops, sunn hemp (Crotalaria juncea L.) and sorghum sudangrass (Sorghum bicolor [L.] Moench x S. bicolor var. Sudanese [Piper] Stapf) were used in a litterbag study in the Central Plateau region of Haiti from May to September, 2013. Residues were placed in litterbags at a rate equivalent to 3.25 Mg residue ha(-1) either on the soil surface or buried at 15 cm to represent a tilled and no-tillage system, respectively. Initial C:N ratios were: maize > common bean > sorghum sudangrass > sunn hemp. Highest residue mass loss rates and C and N mineralization generally occurred in the reverse order. Overall, surface-placed residues decomposed more slowly with 40 and 17 % of initial residue mass of surface and buried residues, respectively, remaining at 112 days. Carbon and N mineralization was higher when residues were buried. Net N mineralization of buried residues was 0.12, 0.07, 0.06, and 0.03 g N g residue(-1) for sunn hemp, sorghum sudangrass, maize, and common bean, respectively over 112 days. To achieve the goal of increasing nutrient supply while maintaining year-round cover, a combination of grass and legume cover crops may be required with benefits increasing over multiple seasons. PMID:27429883

  20. METABOLIC ENGINEERING TO DEVELOP A PATHWAY FOR THE SELECTIVE CLEAVAGE OF CARBON-NITROGEN BONDS

    Energy Technology Data Exchange (ETDEWEB)

    John J. Kilbane III

    2003-12-01

    pathway. The construction of a new metabolic pathway to selectively remove nitrogen from carbazole and other molecules typically found in petroleum should lead to the development of a process to improve oil refinery efficiency by reducing the poisoning, by nitrogen, of catalysts used in the hydrotreating and catalytic cracking of petroleum.

  1. Visualizing Single Cell Biology: Nanosims Studies of Carbon and Nitrogen Metabolism in Diazotrophic Cyanobacteria

    Science.gov (United States)

    Pett-Ridge, J.; Finzi, J. A.; Capone, D. G.; Popa, R.; Nealson, K. H.; Ng, W.; Spormann, A. M.; Hutcheon, I. D.; Weber, P. K.

    2007-12-01

    , inter-species transfers (with Rhizobium epibionts), and within-cell depth profiles. Spatial enrichment patterns were correlated with morphological features evidenced in TEM images of microtomed filaments. These features indicate how 15N and 13C "hotspots" are dispersed throughout individual cells in different species, and may indicate isolated locations of increased N2 fixation, sites of amino acid/protein synthesis, or cyanophycin storage granules. This combination of Nano-Secondary Ion Mass Spectrometry (NanoSIMS) analysis and high resolution microscopy allows isotopic analysis to be linked to morphological features and holds great promise for fine-scale studies of bacteria metabolism.

  2. Effects of antiepileptic drug monotherapy on one-carbon metabolism and DNA methylation in patients with epilepsy.

    Directory of Open Access Journals (Sweden)

    Guanzhong Ni

    Full Text Available The aim of this study was to compare the serum levels of one-carbon metabolism (OCM nutrients (e.g., folate, homocysteine and vitamin B12 and peripheral blood DNA methylation in epileptic patients under treatment with antiepileptic drugs (AEDs and in healthy controls.In this cross-sectional study, 60 patients with epilepsy who were receiving valproate (VPA (n = 30 or lamotrigine (LTG (n = 30 monotherapy were enrolled. Thirty age and sex matched healthy subjects served as the controls. Serum concentrations of OCM nutrients and peripheral blood DNA methylation status were measured.Compared to the control group, the VPA group had higher serum levels of homocysteine (p<0.05. No difference in homocysteine concentration was observed in the LTG group. Patients receiving VPA or LTG had significantly lower serum folate levels in comparison with controls (p<0.001. The level of methylation of long interspersed nucleotide element-1 (LINE-1 in peripheral blood was not significantly different between the AED monotherapy group and healthy controls. A difference in the methylation levels of methylenetetrahydrofolate reductase (MTHFR amplicon was observed between AED-treated patients with epilepsy and controls (p<0.01. A positive correlation between serum folate levels and peripheral blood MTHFR amplicon methylation status was also observed (r = 0.25, p = 0.023.Our findings suggest that the effects of AED monotherapy on OCM may induce specific regions of DNA hypomethylation.

  3. Nitrogen and carbon source balance determines longevity, independently of fermentative or respiratory metabolism in the yeast Saccharomyces cerevisiae.

    Science.gov (United States)

    Santos, Júlia; Leitão-Correia, Fernanda; Sousa, Maria João; Leão, Cecília

    2016-04-26

    Dietary regimens have proven to delay aging and age-associated diseases in several eukaryotic model organisms but the input of nutritional balance to longevity regulation is still poorly understood. Here, we present data on the role of single carbon and nitrogen sources and their interplay in yeast longevity. Data demonstrate that ammonium, a rich nitrogen source, decreases chronological life span (CLS) of the prototrophic Saccharomyces cerevisiae strain PYCC 4072 in a concentration-dependent manner and, accordingly, that CLS can be extended through ammonium restriction, even in conditions of initial glucose abundance. We further show that CLS extension depends on initial ammonium and glucose concentrations in the growth medium, as long as other nutrients are not limiting. Glutamine, another rich nitrogen source, induced CLS shortening similarly to ammonium, but this effect was not observed with the poor nitrogen source urea. Ammonium decreased yeast CLS independently of the metabolic process activated during aging, either respiration or fermentation, and induced replication stress inhibiting a proper cell cycle arrest in G0/G1 phase. The present results shade new light on the nutritional equilibrium as a key factor on cell longevity and may contribute for the definition of interventions to promote life span and healthy aging. PMID:27072582

  4. The carbon assimilation network in Escherichia coli is densely connected and largely sign-determined by directions of metabolic fluxes.

    Directory of Open Access Journals (Sweden)

    Valentina Baldazzi

    2010-06-01

    Full Text Available Gene regulatory networks consist of direct interactions but also include indirect interactions mediated by metabolites and signaling molecules. We describe how these indirect interactions can be derived from a model of the underlying biochemical reaction network, using weak time-scale assumptions in combination with sensitivity criteria from metabolic control analysis. We apply this approach to a model of the carbon assimilation network in Escherichia coli. Our results show that the derived gene regulatory network is densely connected, contrary to what is usually assumed. Moreover, the network is largely sign-determined, meaning that the signs of the indirect interactions are fixed by the flux directions of biochemical reactions, independently of specific parameter values and rate laws. An inversion of the fluxes following a change in growth conditions may affect the signs of the indirect interactions though. This leads to a feedback structure that is at the same time robust to changes in the kinetic properties of enzymes and that has the flexibility to accommodate radical changes in the environment.

  5. Layer-by-layer carbon nanotube bio-templates for in situ monitoring of the metabolic activity of nitrifying bacteria

    Science.gov (United States)

    Loh, Kenneth J.; Guest, Jeremy S.; Ho, Genevieve; Lynch, Jerome P.; Love, Nancy G.

    2009-03-01

    Despite the wide variety of effective disinfection and wastewater treatment techniques for removing organic and inorganic wastes, pollutants such as nitrogen remain in wastewater effluents. If left untreated, these nitrogenous wastes can adversely impact the environment by promoting the overgrowth of aquatic plants, depleting dissolved oxygen, and causing eutrophication. Although nitrification/denitrification processes are employed during advanced wastewater treatment, effective and efficient operation of these facilities require information of the pH, dissolved oxygen content, among many other parameters, of the wastewater effluent. In this preliminary study, a biocompatible CNT-based nanocomposite is proposed and validated for monitoring the biological metabolic activity of nitrifying bacteria in wastewater effluent environments (i.e., to monitor the nitrification process). Using carbon nanotubes and a pH-sensitive conductive polymer (i.e., poly(aniline) emeraldine base), a layer-by-layer fabrication technique is employed to fabricate a novel thin film pH sensor that changes its electrical properties in response to variations in ambient pH environments. Laboratory studies are conducted to evaluate the proposed nanocomposite's biocompatibility with wastewater effluent environments and its pH sensing performance.

  6. Nitrogen and carbon source balance determines longevity, independently of fermentative or respiratory metabolism in the yeast Saccharomyces cerevisiae

    Science.gov (United States)

    Santos, Júlia; Leitão-Correia, Fernanda

    2016-01-01

    Dietary regimens have proven to delay aging and age-associated diseases in several eukaryotic model organisms but the input of nutritional balance to longevity regulation is still poorly understood. Here, we present data on the role of single carbon and nitrogen sources and their interplay in yeast longevity. Data demonstrate that ammonium, a rich nitrogen source, decreases chronological life span (CLS) of the prototrophic Saccharomyces cerevisiae strain PYCC 4072 in a concentration-dependent manner and, accordingly, that CLS can be extended through ammonium restriction, even in conditions of initial glucose abundance. We further show that CLS extension depends on initial ammonium and glucose concentrations in the growth medium, as long as other nutrients are not limiting. Glutamine, another rich nitrogen source, induced CLS shortening similarly to ammonium, but this effect was not observed with the poor nitrogen source urea. Ammonium decreased yeast CLS independently of the metabolic process activated during aging, either respiration or fermentation, and induced replication stress inhibiting a proper cell cycle arrest in G0/G1 phase. The present results shade new light on the nutritional equilibrium as a key factor on cell longevity and may contribute for the definition of interventions to promote life span and healthy aging. PMID:27072582

  7. Effect of Carbon Monoxide Donor CORM-2 on Vitamin D3 Metabolism

    Directory of Open Access Journals (Sweden)

    Martina Feger

    2013-11-01

    Full Text Available Background/Aims: Carbon monoxide (CO interferes with cytochrome-dependent cellular functions and acts as gaseous transmitter. CO is released from CO-releasing molecules (CORM including tricarbonyl-dichlororuthenium (II dimer (CORM-2, molecules considered for the treatment of several disorders including vascular dysfunction, inflammation, tissue ischemia and organ rejection. Cytochrome P450-sensitive function include formation of 1,25-dihydroxyvitamin D3 (1,25(OH2D3 by renal 25-hydroxyvitamin D3 1-alpha-hydroxylase (Cyp27b1. The enzyme is regulated by PTH, FGF23 and klotho. 1,25(OH2D3 regulates Ca2+ and phosphate transport as well as klotho expression. The present study explored, whether CORM-2 influences 1,25(OH2D3 formation and klotho expression. Methods: Mice were treated with intravenous CORM-2 (20 mg/kg body weight. Plasma 1,25(OH2D3 and FGF23 concentrations were determined by ELISA, phosphate, calcium and creatinine concentrations by colorimetric methods, transcript levels by quantitative RT-PCR and protein expression by western blotting. Fgf23 mRNA transcript levels were further determined in rat osteosarcoma UMR106 cells without or with prior treatment for 24 hours with 20 µM CORM-2. Results: CORM-2 injection within 24 hours significantly increased FGF23 plasma levels and decreased 1,25(OH2D3 plasma levels, renal Cyp27b1 gene expression as well as renal klotho protein abundance and transcript levels. Moreover, treatment of UMR106 cells with CORM-2 significantly increased Fgf23 transcript levels. Conclusion: CO-releasing molecule CORM-2 enhances FGF23 expression and release and decreases klotho expression and 1,25(OH2D3 synthesis.

  8. Modelling and analysis of central metabolism operating regulatory interactions in salt stress conditions in a L-carnitine overproducing E. coli strain.

    Directory of Open Access Journals (Sweden)

    Guido Santos

    Full Text Available Based on experimental data from E. coli cultures, we have devised a mathematical model in the GMA-power law formalism that describes the central and L-carnitine metabolism in and between two steady states, non-osmotic and hyperosmotic (0.3 M NaCl. A key feature of this model is the introduction of type of kinetic order, the osmotic stress kinetic orders (g(OSn, derived from the power law general formalism, which represent the effect of osmotic stress in each metabolic process of the model.By considering the values of the g(OSn linked to each metabolic process we found that osmotic stress has a positive and determinant influence on the increase in flux in energetic metabolism (glycolysis; L-carnitine biosynthesis production; the transformation/excretion of Acetyl-CoA into acetate and ethanol; the input flux of peptone into the cell; the anabolic use of pyruvate and biomass decomposition. In contrast, we found that although the osmotic stress has an inhibitory effect on the transformation flux from the glycolytic end products (pyruvate to Acetyl-CoA, this inhibition is counteracted by other effects (the increase in pyruvate concentration to the extent that the whole flux increases. In the same vein, the down regulation exerted by osmotic stress on fumarate uptake and its oxidation and the production and export of lactate and pyruvate are reversed by other factors up to the point that the first increased and the second remained unchanged.The model analysis shows that in osmotic conditions the energy and fermentation pathways undergo substantial rearrangement. This is illustrated by the observation that the increase in the fermentation fluxes is not connected with fluxes towards the tricaboxylic acid intermediates and the synthesis of biomass. The osmotic stress associated with these fluxes reflects these changes. All these observations support that the responses to salt stress observed in E. coli might be conserved in halophiles.Flux evolution

  9. Ozone, carbon monoxide and nitrogen oxides time series at four alpine GAW mountain stations in central Europe

    Directory of Open Access Journals (Sweden)

    S. Gilge

    2010-12-01

    Full Text Available Long-term, ground based in-situ observations of ozone (O3 and its precursor gases nitrogen dioxide (NO2 and carbon monoxide (CO from the four sites Hohenpeissenberg and Zugspitze (D, Sonnblick (A and Jungfraujoch (CH are presented for the period 1995–2007. These Central European alpine mountain observatories cover an altitude range of roughly 1000 to 3500 m. Comparable analytical methods and common quality assurance (QA procedures are used at all sites. For O3 and CO, calibration is linked to primary calibrations (O3 or CO standards provided by the Central Calibration Laboratory (CCL at NOAA/ESRL. All stations have been audited by the World Calibration Centre (WCC for CO and O3 (WCC-Empa; CH. Data from long-term measurements of NO2 and CO are only available from Hohenpeissenberg and Jungfraujoch. Both sites show slightly decreasing mixing ratios of the primarily emitted NO2 and the partly anthropogenically emitted CO between 1995 and 2007. The findings are generally consistent with shorter observation periods at Zugspitze and Sonnblick and thus are considered to represent regional changes in Central European atmospheric composition at this altitude range. Over the same period, 1995–2007, the O3 mixing ratios have slightly increased at three of the four sites independent of wind sector. Trends are often more pronounced in winter and less in summer; highest declines of NO2 and CO are observed in winter and the lowest in summer, whereas the strongest O3 increase was detected in winter and lowest or even decline in summer, respectively. Weekly cycles demonstrate anthropogenic impact at all elevations with enhanced NO2 on working days compared to weekends. Enhanced O3 values on working days indicating photochemical production from anthropogenic precursors are only observed in summer, whereas in all other seasons anti

  10. Ozone, Carbon monoxide and Nitrogen oxides time series at four Alpine GAW mountain stations in Central Europe

    Directory of Open Access Journals (Sweden)

    S. Gilge

    2010-08-01

    Full Text Available Long-term, ground based in-situ observations of Ozone (O3 and its precursor gases Nitrogen dioxide (NO2 and Carbon monoxide (CO from the four sites Hohenpeissenberg and Zugspitze (D, Sonnblick (A and Jungfraujoch (CH are presented for the period 1995–2007. These Central European alpine mountain observatories cover an altitude range of roughly 1000 to 3500 m. Comparable analytical methods and common quality assurance (QA procedures are used at all sites. For O3 and CO, calibration is linked to primary calibrations (O3 or CO standards provided by the Central Calibration Laboratory (CCL at NOAA/ESRL. All stations have been audited by the World Calibration Centre (WCC for CO and O3 (WCC-Empa; CH. Data from long-term measurements of NO2 and CO are only available from Hohenpeissenberg and Jungfraujoch. Both sites show slightly decreasing mixing ratios of the primarily emitted NO2 and the partly anthropogenically emitted CO between 1995 and 2007. The findings are generally consistent with shorter observation periods at Zugspitze and Sonnblick and thus are considered to represent regional changes in Central European atmospheric composition at this altitude range. Over the same period 1995–2007, the O3 mixing ratios have slightly increased at three of the four sites. This was observed independent of wind sector and for most seasons, with a tendency to higher positive trends in winter and lower and partly negative trends in summer. Trends are often more pronounced in winter and less in summer; highest declines of NO2 and CO are observed in winter and the lowest in summer, whereas the highest rate of O3 increase was detected in winter and lowest in summer, respectively. Weekly cycles demonstrate anthropogenic impact at all elevations with enhanced NO2 on working days compared to weekends. Enhanced O3 values on working days

  11. Perfil metabólico e antropométrico dos Suyá: Parque Indígena do Xingu, Brasil Central Metabolic and anthropometric profile of Suyá: Xingu Indigenous Park, Central Brazil

    Directory of Open Access Journals (Sweden)

    Vera Lúcia Morais Antonio de Salvo

    2009-09-01

    Full Text Available OBJETIVO: Descrever o perfil metabólico e antropométrico de índios Suyá que vivem no Parque Indígena do Xingu (Mato Grosso. MÉTODO: Neste estudo transversal foram avaliados 86 índios Suyá com idade de > 20 anos, de ambos os sexos. Durante o exame físico foram obtidos os valores de pressão arterial, peso, altura, perímetros corporais e dobras cutâneas. Amostras de sangue foram coletadas para dosagem de lipoproteínas, glicemia e ácido úrico. Na análise dos dados foram utilizados os testes estatísticos qui-quadrado (para proporções ou t de Student (para valores médios nas comparações das distribuições das variáveis relativas ao estado nutricional e perfil metabólico, segundo sexo e faixa etária dos sujeitos. RESULTADOS: As mulheres, quando comparadas aos homens, apresentaram valores médios estatisticamente menores das variáveis antropométricas (peso, índice de massa corporal, perímetro de cintura, do braço e dobras cutâneas, de pressão arterial, triglicérides, VLDL e ácido úrico. Foram encontrados, entre os Suyá, 46,5%, com excesso de peso, 12,8% com obesidade generalizada, 38,4% com obesidade central, 26,7%, apresentaram alterações pressóricas, 4% glicemia de jejum alterada, 63,9% dislipidemia e 21,9% síndrome metabólica. CONCLUSÃO: Foram observadas alterações metabólicas e antropométricas entre os índios Suyá. Intervenções educativas devem ser implementadas para resgatar hábitos e estilo de vida tradicionais a fim de conter o avanço deste quadro.OBJECTIVE: To describe the metabolic and anthropometric profile of Suyá people living in the Xingu Indigenous Park (Mato Grosso. METHOD: In this cross-sectional study, we evaluated 86 Suyá Indians aged >20 years, of both genders. During the physical examination, we measured blood pressure, weight, height, body perimeters, and skin fold thickness. Samples of blood were collected for lipoprotein, glucose, and uric acid dosage. Chi-square (proportions

  12. New Features on the Environmental Regulation of Metabolism Revealed by Modeling the Cellular Proteomic Adaptations Induced by Light, Carbon, and Inorganic Nitrogen in Chlamydomonas reinhardtii.

    Science.gov (United States)

    Gérin, Stéphanie; Leprince, Pierre; Sluse, Francis E; Franck, Fabrice; Mathy, Grégory

    2016-01-01

    Microalgae are currently emerging to be very promising organisms for the production of biofuels and high-added value compounds. Understanding the influence of environmental alterations on their metabolism is a crucial issue. Light, carbon and nitrogen availability have been reported to induce important metabolic adaptations. So far, the influence of these variables has essentially been studied while varying only one or two environmental factors at the same time. The goal of the present work was to model the cellular proteomic adaptations of the green microalga Chlamydomonas reinhardtii upon the simultaneous changes of light intensity, carbon concentrations (CO2 and acetate), and inorganic nitrogen concentrations (nitrate and ammonium) in the culture medium. Statistical design of experiments (DOE) enabled to define 32 culture conditions to be tested experimentally. Relative protein abundance was quantified by two dimensional differential in-gel electrophoresis (2D-DIGE). Additional assays for respiration, photosynthesis, and lipid and pigment concentrations were also carried out. A hierarchical clustering survey enabled to partition biological variables (proteins + assays) into eight co-regulated clusters. In most cases, the biological variables partitioned in the same cluster had already been reported to participate to common biological functions (acetate assimilation, bioenergetic processes, light harvesting, Calvin cycle, and protein metabolism). The environmental regulation within each cluster was further characterized by a series of multivariate methods including principal component analysis and multiple linear regressions. This metadata analysis enabled to highlight the existence of a clear regulatory pattern for every cluster and to mathematically simulate the effects of light, carbon, and nitrogen. The influence of these environmental variables on cellular metabolism is described in details and thoroughly discussed. This work provides an overview of the

  13. New Features on the Environmental Regulation of Metabolism Revealed by Modeling the Cellular Proteomic Adaptations Induced by Light, Carbon, and Inorganic Nitrogen in Chlamydomonas reinhardtii

    Science.gov (United States)

    Gérin, Stéphanie; Leprince, Pierre; Sluse, Francis E.; Franck, Fabrice; Mathy, Grégory

    2016-01-01

    Microalgae are currently emerging to be very promising organisms for the production of biofuels and high-added value compounds. Understanding the influence of environmental alterations on their metabolism is a crucial issue. Light, carbon and nitrogen availability have been reported to induce important metabolic adaptations. So far, the influence of these variables has essentially been studied while varying only one or two environmental factors at the same time. The goal of the present work was to model the cellular proteomic adaptations of the green microalga Chlamydomonas reinhardtii upon the simultaneous changes of light intensity, carbon concentrations (CO2 and acetate), and inorganic nitrogen concentrations (nitrate and ammonium) in the culture medium. Statistical design of experiments (DOE) enabled to define 32 culture conditions to be tested experimentally. Relative protein abundance was quantified by two dimensional differential in-gel electrophoresis (2D-DIGE). Additional assays for respiration, photosynthesis, and lipid and pigment concentrations were also carried out. A hierarchical clustering survey enabled to partition biological variables (proteins + assays) into eight co-regulated clusters. In most cases, the biological variables partitioned in the same cluster had already been reported to participate to common biological functions (acetate assimilation, bioenergetic processes, light harvesting, Calvin cycle, and protein metabolism). The environmental regulation within each cluster was further characterized by a series of multivariate methods including principal component analysis and multiple linear regressions. This metadata analysis enabled to highlight the existence of a clear regulatory pattern for every cluster and to mathematically simulate the effects of light, carbon, and nitrogen. The influence of these environmental variables on cellular metabolism is described in details and thoroughly discussed. This work provides an overview of the

  14. New Features on the Environmental Regulation of Metabolism Revealed by Modeling the Cellular Proteomic Adaptations Induced by Light, Carbon, and Inorganic Nitrogen in Chlamydomonas reinhardtii.

    Science.gov (United States)

    Gérin, Stéphanie; Leprince, Pierre; Sluse, Francis E; Franck, Fabrice; Mathy, Grégory

    2016-01-01

    Microalgae are currently emerging to be very promising organisms for the production of biofuels and high-added value compounds. Understanding the influence of environmental alterations on their metabolism is a crucial issue. Light, carbon and nitrogen availability have been reported to induce important metabolic adaptations. So far, the influence of these variables has essentially been studied while varying only one or two environmental factors at the same time. The goal of the present work was to model the cellular proteomic adaptations of the green microalga Chlamydomonas reinhardtii upon the simultaneous changes of light intensity, carbon concentrations (CO2 and acetate), and inorganic nitrogen concentrations (nitrate and ammonium) in the culture medium. Statistical design of experiments (DOE) enabled to define 32 culture conditions to be tested experimentally. Relative protein abundance was quantified by two dimensional differential in-gel electrophoresis (2D-DIGE). Additional assays for respiration, photosynthesis, and lipid and pigment concentrations were also carried out. A hierarchical clustering survey enabled to partition biological variables (proteins + assays) into eight co-regulated clusters. In most cases, the biological variables partitioned in the same cluster had already been reported to participate to common biological functions (acetate assimilation, bioenergetic processes, light harvesting, Calvin cycle, and protein metabolism). The environmental regulation within each cluster was further characterized by a series of multivariate methods including principal component analysis and multiple linear regressions. This metadata analysis enabled to highlight the existence of a clear regulatory pattern for every cluster and to mathematically simulate the effects of light, carbon, and nitrogen. The influence of these environmental variables on cellular metabolism is described in details and thoroughly discussed. This work provides an overview of the

  15. Isolation of a non-fermentative bacterium, Pseudomonas aeruginosa, using intracellular carbon for denitrification and phosphorus-accumulation and relevant metabolic mechanisms.

    Science.gov (United States)

    Liu, Hui; Wang, Qin; Sun, Yanfu; Zhou, Kangqun; Liu, Wen; Lu, Qian; Ming, Caibing; Feng, Xidan; Du, Jianjun; Jia, Xiaoshan; Li, Jun

    2016-07-01

    A newly designed pilot-scale system was developed to enrich denitrifying phosphate-accumulating organisms (DNPAOs) for nitrogen and phosphorus nutrient removal synchronously. A strain of DNPAOs was isolated and its biochemical characteristics and metabolic mechanisms of this bacterial strain were analyzed. The results showed that compared with previously reported system, this newly designed system has higher removal rates of nutrients. Removal efficiencies of NH3-N, TN, TP, and COD in actual wastewater were 82.64%, 79.62%, 87.22%, and 90.41%, respectively. Metabolic activity of DNPAOs after anoxic stage in this study even reached 94.64%. Pseudomonas aeruginosa is a strain of non-fermentative DNPAOs with strong nitrogen and phosphorus removal abilities. Study on the metabolic mechanisms suggested that intracellular PHB of P. aeruginosa plays dual roles, supplying energy for phosphorus accumulation and serving as a major carbon source for denitrification. PMID:26995616

  16. Charge exchange recombination spectroscopy measurements in the extreme ultraviolet region of central carbon concentrations during high power neutral beam heating in TFTR [Tokamak Fusion Test Reactor

    International Nuclear Information System (INIS)

    The carbon concentration in the central region of TFTR discharges with high power neutral beam heating has been measured by charge-extracted recombination spectroscopy (CXRS) of the C+5 n = 3--4 transition in the extreme ultraviolet region. The carbon concentrations were deduced from absolute measurements of the line brightness using a calculation of the beam attenuation and the appropriate cascade-corrected line excitation rates. As a result of the high ion temperatures in most of the discharges, the contribution of beam halo neutrals to the line brightness was significant and therefore had to be included in the modeling of the data. Carbon concentrations have been measured in discharges with Ip = 1.0-1.6 MA and beam power in the range of 2.6-30 MW, including a number of supershots. The results are in good agreement with carbon concentrations deduced from the visible bremsstrahlung Zeff and metallic impurity concentrations measured by x-ray pulse-height analysis, demonstrating the reliability of the atomic rates used in the beam attenuation and line excitation calculations. Carbon is the dominant impurity species in these discharges; the oxygen concentration measured via CXRS in a high beam power case was 0.0006 of ne, compard to 0.04 for carbon. Trends with Ip and beam power in the carbon concentration and the inferred deuteron concentration are presented. The carbon concentration is independent of Ip and decreases from 0.13 at 2.6 MW beam power to 0.04 at 30 MW, while the deuteron concentration increases from 0.25 to 0.75 over the same range of beam power. These changes are primarily the result of beam particle fueling, as the carbon density did not vary significantly with beam power. The time evolutions of the carbon and deuteron concentrations during two high power beam pulses, one which exhibited a carbon bloom and one which did not, are compared. 30 refs., 12 figs., 2 tabs

  17. Clinical usefulness of positron emission tomography in the evaluation of regional cerebral blood flow and cerebral oxygen metabolism under glycerol and carbon dioxide loadings

    Energy Technology Data Exchange (ETDEWEB)

    Tanada, Shuji; Yonekura, Yoshiharu; Senda, Michio

    1987-02-01

    Cerebral blood flow (CBF) and oxygen metabolism (CMRO/sub 2/) were studied in normal cerebral cortices by positron emission tomography using continuous inhalation method of oxygen-15 labeled carbon dioxide and oxygen, and single inhalation method of oxygen-15 labeled carbon monoxide. The values of CBF, CMRO/sub 2/, and oxygen extraction fraction (OEF) in cerebral cortices of 18 healthy normal volunteers represented 40 +- 7 ml/100 ml/min, 3.2 +- 0.5 ml O/sub 2//100 ml/min, and 0.43 +- 0.07, respectively. In cases with glycerol loading, CBF increased in 10/14 cases. Studies of 6 cases with intracranial pressure indicated the presence of mechanism by which depressed CMRO/sub 2/ improved and was kept in normal values. The loading of 5% carbon dioxide showed an increase in CBF in cases with cerebral infarction, which implied the good cerebral vascular response to the elevated arterial carbon dioxide, but no particular changes were observed in CMRO/sub 2/ which seemed to be less responsive to the elevated arterial carbon dioxide level. In cases with moyamoya disease, 5% carbon dioxide loading showed no changes in CBF and CMRO/sub 2/. This suggested the poor cerebral vascular response to the elevation of arterial carbon dioxide, while X-ray CT failed to demonstrate any abnormalities in corresponding areas. Positron emission tomography proved to have a great potentiality regarding the evaluation of the changes in cerebral blood flow and cerebral oxygen metabolism under various loadings.

  18. Miocene climate as recorded on slope carbonates : examples from Malta (Central Mediterranean) and Northeastern Australia (Marion Plateau, ODP LEG 194)

    Science.gov (United States)

    John, Cédric Michaël

    2003-08-01

    This study investigated the slope carbonates of two Miocene carbonate systems: the Maltese Islands (in the Central Mediterranean) and the Marion Plateau (Northeastern Australia, drilled during ODP Leg 194). The aim of the study was to trace the impact of the Miocene cooling steps (events Mi1-Mi6) in these carbonate systems, especially the Mi3 event, which took place around 13.6 Ma and deeply impacted the marine oxygen isotope record. This event also profoundly impacted oceanographic and climatic patterns, eventually leading to the establishment of the modern ice-house world. In particular, East Antarctica became ice covered at that period. The rational behind the present study was to investigate the impact that this event had on shallow water systems in order to complement the deep-sea record and hence acquire a more global perspective on Miocene climate change. The Maltese Islands were investigated for trends in bulk-rock carbon and oxygen isotopes, as well as bulk-rock mineralogy, clay minerals analysis and organic geochemisty. Results showed that the mid Miocene cooling event deeply impacted sedimentation at that location by changing sedimentation from carbonate to clay-rich sediments. Moreover, it was discovered that each phase of Antarctic glaciation, not just the major mid Miocene event, resulted in higher terrigenous input on Malta. Mass accumulation rates revealed that this was linked to increased runoff during periods when Antarctica was glaciated, and thus that the carbonate sediments were “diluted” by clay-rich sediments. The model subsequently developed to explain this implies feedback from Antarctic glaciations creating cold, dense air masses that push the ITCZ Northward, thus increasing precipitation on the North African subcontinent. Increased precipitation (or stronger African monsoon) accelerated continental weathering and runoff, thus bringing more terrigenous sediment to the paleo-location of the slope sediments of Malta. Spectral analysis of

  19. Carbon of Woody Debris in Plateau-type Karst Evergreen and Deciduous Broad-leaved Mixed Forest of Central Guizhou Province

    Science.gov (United States)

    Wu, Y.; Ni, J.; Liu, L.; Guo, C.

    2014-12-01

    Woody debris (WD) is an essential structural and functional component of forest ecosystems, and plays very significant roles for the biogeochemical cycling of carbon and nutrients. Coarse woody debris (CWD) is considered to be the major part in forest WD and it is primarily composed of logs, snags, stumps and large branches, while fine woody debris (FWD) mainly consists of small twigs. Composition, spatial distribution and carbon storage of WD have been studied in plateau-type karst evergreen and deciduous broad-leaved mixed forest in Tianlong Mountain of central Guizhou Province. Results showed that the carbon storage of WD in karst forests was less than non-karst forests. The major components of WD were fallen trees and snags with 10-20 cm in diameter. Fallen trees and snags with diameter greater than 20 cm were the smallest part of WD. The situation of WD in this region reflects the structural characteristics of WD in mid-late stage of plateau-type karst evergreen and deciduous broad-leaved mixed forest succession. The potential contribution of WD to the regional carbon cycle, and its relationship with climate change were finally discussed. The WD (especially CWD) plays an important role in the carbon cycle of karst forest. Forest WD production and decay rates may partially depend on climatic conditions, the accumulation of CWD and FWD carbon stocks in forests may be correlated with climate. Key words: woody debris, karst forests, carbon storage, spatial distribution, CWD, FWD.

  20. Continuous light increases growth, daily carbon gain, antioxidants, and alters carbohydrate metabolism in a cultivated and a wild tomato species.

    Science.gov (United States)

    Haque, Mohammad S; Kjaer, Katrine H; Rosenqvist, Eva; Ottosen, Carl-Otto

    2015-01-01

    Cultivated tomato species develop leaf injury while grown in continuous light (CL). Growth, photosynthesis, carbohydrate metabolism and antioxidative enzyme activities of a cultivated (Solanum lycopersicum L. 'Aromata') and a wild tomato species (Solanum pimpinellifolium L.) were compared in this study aiming to analyze the species-specific differences and thermoperiod effects in responses to CL. The species were subjected to three photoperiodic treatments for 12 days in climate chambers: 16-h photoperiod with a light/dark temperature of 26/16°C (P16D10 or control); CL with a constant temperature of 23°C (P24D0); CL with a variable temperature of 26/16°C (P24D10). The results showed that both species grown in CL had higher dry matter production due to the continuous photosynthesis and a subsequent increase in carbon gain. In S. lycopersicum, the rate of photosynthesis and the maximum photochemical efficiency of photosystem II declined in CL with the development of leaf chlorosis, reduction in the leaf chlorophyll content and a higher activity of antioxidative enzymes. The normal diurnal patterns of starch and sugar were only present under control conditions. The results demonstrated that CL conditions mainly affected the photosynthetic apparatus of a cultivated species (S. lycopersicum), and to a less degree to the wild species (S. pimpinellifolium). The negative effects of the CL could be alleviated by diurnal temperature variations, but the physiological mechanisms behind these are less clear. The results also show that the genetic potential for reducing the negative effects of CL does exist in the tomato germplasm. PMID:26217371

  1. Continuous light increases growth, daily carbon gain, antioxidants and alters carbohydrate metabolism in a cultivated and a wild tomato species

    Directory of Open Access Journals (Sweden)

    Mohammad Sabibul Haque

    2015-07-01

    Full Text Available Cultivated tomato species develop leaf injury while grown in continuous light (CL. Growth, photosynthesis, carbohydrate metabolism and antioxidative enzyme activities of a cultivated (Solanum lycopersicum L. ‘Aromata’ and a wild tomato species (Solanum pimpinellifolium L. were compared in this study aiming to analyse the species-specific differences and thermoperiod effects in responses to CL. The species were subjected to three photoperiodic treatments for 12 days in climate chambers: 16-h photoperiod with a light/dark temperature of 26/16ºC (P16D10 or control; CL with a constant temperature of 23ºC (P24D0; CL with a variable temperature of 26/16ºC (P24D10. The results showed that both species grown in CL had higher dry matter production due to the continuous photosynthesis and a subsequent increase in carbon gain. In S. lycopersicum, the rate of photosynthesis and the maximum photochemical efficiency of photosystem II declined in CL with the development of leaf chlorosis, reduction in the leaf chlorophyll content and a higher activity of antioxidative enzymes. The normal diurnal patterns of starch and sugar were only present under control conditions. The results demonstrated that CL conditions mainly affected the photosynthetic apparatus of a cultivated species (S. lycopersicum, and to a less degree to the wild species (S. pimpinellifolium. The negative effects of the CL could be alleviated by diurnal temperature variations, but the physiological mechanisms behind these are less clear. The results also show that the genetic potential for reducing the negative effects of CL does exist in the tomato germplasm.

  2. Mass concentrations of black carbon measured by four instruments in the middle of Central East China in June 2006

    Science.gov (United States)

    Kanaya, Y.; Komazaki, Y.; Pochanart, P.; Liu, Y.; Akimoto, H.; Gao, J.; Wang, T.; Wang, Z.

    2008-12-01

    Mass concentrations of black carbon (BC) were determined in June 2006 at the top of Mount Tai (36.26° N, 117.11° E, 1534 m a.s.l.), located in the middle of Central East China, using four different instruments: a multi-angle absorption photometer (5012 MAAP, Thermo), a particle soot absorption photometer (PSAP, Radiance Research), an ECOC semi-continuous analyzer (Sunset Laboratory) and an Aethalometer (AE-21, Magee Scientific). High correlation coefficients (R2>0.88) were obtained between the measurements of the BC mass concentrations made using the different instruments. From the range of the slopes of the linear least-square fittings, we concluded that BC concentrations regionally-representative of the area were measured in a range with a maximum-to-minimum ratio of 1.5 (an exception was that the BC (PM2.5) concentrations derived from MAAP were ~2 times higher than the optical measurements (PM2.5) derived from the ECOC analyzer). While this range is significant, it is still sufficiently narrow to better constrain the large and highly uncertain emission rate of BC from Central East China. In detail, two optical instruments (the MAAP and the PSAP equipped with a heated inlet 400°C) tended to give higher concentrations than the thermal EC concentrations observed by the ECOC analyzer. The ratios of optical BC to thermal EC showed a positive correlation with the OC/EC ratio reported by the ECOC analyzer, suggesting two explanations. One is that the optical instruments overestimated BC concentrations in spite of careful cancellation of the scattering effect in the MAAP instrument and the expected evaporation of volatile species by heating the inlet of the PSAP instrument. The other is that the determined split points between OC and EC were too late when a large amount of OC underwent charring during the analysis, resulting in an underestimation of EC by the ECOC analyzer. High ratios of optical BC to thermal EC were recorded when the NOx/NOy ratio was low, implying

  3. Mass concentrations of black carbon measured by four instruments in the middle of Central East China in June 2006

    Directory of Open Access Journals (Sweden)

    Y. Kanaya

    2008-12-01

    Full Text Available Mass concentrations of black carbon (BC were determined in June 2006 at the top of Mount Tai (36.26° N, 117.11° E, 1534 m a.s.l., located in the middle of Central East China, using four different instruments: a multi-angle absorption photometer (5012 MAAP, Thermo, a particle soot absorption photometer (PSAP, Radiance Research, an ECOC semi-continuous analyzer (Sunset Laboratory and an Aethalometer (AE-21, Magee Scientific. High correlation coefficients (R2>0.88 were obtained between the measurements of the BC mass concentrations made using the different instruments. From the range of the slopes of the linear least-square fittings, we concluded that BC concentrations regionally-representative of the area were measured in a range with a maximum-to-minimum ratio of 1.5 (an exception was that the BC (PM2.5 concentrations derived from MAAP were ~2 times higher than the optical measurements (PM2.5 derived from the ECOC analyzer. While this range is significant, it is still sufficiently narrow to better constrain the large and highly uncertain emission rate of BC from Central East China. In detail, two optical instruments (the MAAP and the PSAP equipped with a heated inlet 400°C tended to give higher concentrations than the thermal EC concentrations observed by the ECOC analyzer. The ratios of optical BC to thermal EC showed a positive correlation with the OC/EC ratio reported by the ECOC analyzer, suggesting two explanations. One is that the optical instruments overestimated BC concentrations in spite of careful cancellation of the scattering effect in the MAAP instrument and the expected evaporation of volatile species by heating the inlet of the PSAP instrument. The other is that the determined split points between OC and EC were too late when a large amount of OC underwent charring during the analysis, resulting in an underestimation of EC by the ECOC analyzer. High ratios of optical BC to thermal EC were

  4. Dietary total antioxidant capacity is inversely related to central adiposity as well as to metabolic and oxidative stress markers in healthy young adults

    Directory of Open Access Journals (Sweden)

    Zulet M Ángeles

    2011-08-01

    Full Text Available Abstract Background Dietary total antioxidant capacity (TAC has been assumed as a useful tool to assess the relationship between the cumulative antioxidant food capacity and several chronic disorders. The aim of this cross-sectional study was to investigate the potential relationships of dietary TAC with adiposity, metabolic and oxidative stress markers in healthy young adults. Methods This study enrolled 266 healthy subjects (105 men/ 161 women; 22 ± 3 years-old; 22.0 ± 2.7 kg/m2. Dietary intake, anthropometry, blood pressure, lifestyle features, and biochemical data were assessed with validated procedures. Results In linear regression analyses, dietary TAC values were inversely associated with glycemia, total cholesterol:HDL-c ratio, triglycerides and oxidized-LDL concentrations, and positively associated with HDL-c concentrations, independently of gender, age, smoking status, physical activity, vitamin use supplement, waist circumference, energy intake, fatty acid intake. In addition, plasma TAC was negatively correlated with ox-LDL concentrations (r= -0.20, P = 0.003, independently of the assessed confounding variables. Finally, dietary TAC values were inversely related to waist circumference values (r= -0.17, P = 0.005 as well as to lower mild central obesity occurrence (waist circumference ≥ 80/ 94 cm for women/ men, respectively. Conclusion Dietary TAC values are inversely associated with glucose and lipid biomarkers as well as with central adiposity measurements in healthy young adults, indicating dietary TAC as a useful tool to assess the health benefits of cumulative antioxidant capacity from food intake. In addition, the independent and inverse relationships of ox-LDL concentrations with dietary and plasma TAC respectively suggest a putative role of antioxidant rich-diet in the link between redox state and atherogenesis at early stage.

  5. Biosynthesis and Metabolic Fate of Phenylalanine in Conifers.

    Science.gov (United States)

    Pascual, María B; El-Azaz, Jorge; de la Torre, Fernando N; Cañas, Rafael A; Avila, Concepción; Cánovas, Francisco M

    2016-01-01

    The amino acid phenylalanine (Phe) is a critical metabolic node that plays an essential role in the interconnection between primary and secondary metabolism in plants. Phe is used as a protein building block but it is also as a precursor for numerous plant compounds that are crucial for plant reproduction, growth, development, and defense against different types of stresses. The metabolism of Phe plays a central role in the channeling of carbon from photosynthesis to the biosynthesis of phenylpropanoids. The study of this metabolic pathway is particularly relevant in trees, which divert large amounts of carbon into the biosynthesis of Phe-derived compounds, particularly lignin, an important constituent of wood. The trunks of trees are metabolic sinks that consume a considerable percentage of carbon and energy from photosynthesis, and carbon is finally immobilized in wood. This paper reviews recent advances in the biosynthesis and metabolic utilization of Phe in conifer trees. Two alternative routes have been identified: the ancient phenylpyruvate pathway that is present in microorganisms, and the arogenate pathway that possibly evolved later during plant evolution. Additionally, an efficient nitrogen recycling mechanism is required to maintain sustained growth during xylem formation. The relevance of phenylalanine metabolic pathways in wood formation, the biotic interactions, and ultraviolet protection is discussed. The genetic manipulation and transcriptional regulation of the pathways are also outlined. PMID:27468292

  6. Central composite design approach towards optimization of flamboyant pods derived steam activated carbon for its use as heterogeneous catalyst in transesterification of Hevea brasiliensis oil

    International Nuclear Information System (INIS)

    Highlights: • Activated carbon was prepared from novel precursor flamboyant pods (Delonix regia). • Activation process was optimized using central composite design approach. • Prepared activated carbon at optimized condition was used as support for KOH. • Carbon based heterogeneous catalyst was used in transesterification of HBO. • Effect of catalyst loading and alcohol ratio on biodiesel yield was studied. - Abstract: The present investigation emphasises the preparation of carbon based KOH impregnated heterogeneous catalyst from flamboyant pods (Delonix regia) for the production of biodiesel from novel feedstock Hevea brasiliensis oil (HBO). Initially, carbonized char was physically activated by superheated steam and the process was optimized to study the effects of activation time and temperature by central composite design approach (CCD) using response surface methodology (RSM). Activated carbon was impregnated with KOH at four different ratios. Biodiesel production process was carried out at constant temperature 60 °C, reaction time 1 h, and 5 g of carbon based catalyst at varying quantities of catalyst loading (0.5, 2, 3.5, 5 wt%) and methanol to oil ratio (5:1–20:1). The influence of parameters on the biodiesel yield at varied condition was studied. Maximum yield of 89.3% was obtained at methanol to oil ratio 15:1 and catalyst loading 3.5 wt% and corresponding yield at same process parameters was observed to be 88.7% implying the significant activity of catalyst in reutilization. Produced biodiesel was characterized following ASTM standards. The experimental analysis confirmed that the carbonaceous catalyst developed from flamboyant pods under optimized condition is capable of transesterifying HBO into biodiesel

  7. Promotion of renewable energy to mitigate impact of heavy use of carbon energy on society and climate change in Central Sub-Saharan Africa remote areas.

    Science.gov (United States)

    Kenfack, Joseph; Bignom, Blaise

    2015-04-01

    Sub-Saharan Africa owns important renewable energy potential and is still heavily using carbon energy. This is having a negative impact on the climate and on the environment. Given the local cost of carbon energy, the purchase power of people, the availability and the reserve of carbon energy in the area, this resource is being heavily used. This practice is harmful to the climate and is also resulting on poor effort to promote renewable energy in remote areas. The important renewable energy potential is still suffering from poor development. The purpose of this paper is among other things aiming at showing the rate of carbon energy use and its potential impact on climate and environment. We will also ensure that the renewable energy resources of Central Sub-Saharan Africa are known and are subject to be used optimally to help mitigate climate change. After showing some negative impacts of carbon energy used in the area, the work also suggests actions to promote and sustain the development of renewable energy. Based on the knowledge of the Central African energy sector, this paper will identify actions for reduce access to carbon energy and improved access to sustainable, friendly, affordable energy services to users as well as a significant improvement of energy infrastructure and the promotion of energy efficiency. We will show all type of carbon energy used, the potential for solar, biomass and hydro while showing where available the level of development. After a swot analysis of the situation, identified obstacles for the promotion of clean energy will be targeted. Finally, suggestions will be made to help the region develop a vision aiming at developing good clean energy policy to increase the status of renewable energy and better contribute to fight against climate change. Cameroon case study will be examined as illustration. Analysis will be made from data collected in the field. |End Text|

  8. Carbon and nitrogen allocations in corn grown in Central and Northeast China:different responses to fertilization treatments

    Institute of Scientific and Technical Information of China (English)

    MIAO Hui-tian; L Jia-long; XU Ming-gang; ZHANG Wen-ju; HUANG Shao-min; PENG Chang; CHEN Li-ming

    2015-01-01

    In order to reveal the impact of various fertilization strategies on carbon (C) and nitrogen (N) accumulation and al ocation in corn (Zea mays L.), corn was grown in the ifelds where continuous fertilization management had been lasted about 18 years at two sites located in Central and Northeast China (Zhengzhou and Gongzhuling), and biomass C and N contents in different organs of corn at harvest were analyzed. The fertilization treatments included non-fertilizer (control), chemical fertilizers of either nitrogen (N), or nitrogen and phosphorus (NP), or phosphorus and potassium (PK), or nitrogen, phospho-rus and potassium (NPK), NPK plus manure (NPKM), 150%of the NPKM (1.5NPKM), and NPK plus straw (NPKS). The results showed that accumulated C in aboveground ranged from 2 550–5 630 kg ha–1 in the control treatment to 9 300–9 610 kg ha–1 in the NPKM treatment, of which 57–67%and 43–50%were al ocated in the non-grain organs, respectively. Accumulated N in aboveground ranged from 44.8–55.2 kg ha–1 in the control treatment to 211–222 kg ha–1 in the NPKM treatment, of which 35–48% and 33–44% were al ocated in the non-grain parts, respectively. C al ocated to stem and leaf for the PK treatment was 65 and 49%higher than that for the NPKM treatment at the both sites, respectively, while N al ocated to the organs for the PK treatment was 18 and 6%higher than that for the NPKM treatment, respectively. This study demonstrated that responses of C and N al ocation in corn to fertilization strategies were different, and C al ocation was more sensitive to fertilization treatments than N al ocation in the area.

  9. Implications of floristic and environmental variation for carbon cycle dynamics in boreal forest ecosystems of central Canada

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Zicheng; Apps, M.J.; Bhatti, J.S. [Canadan Forest Service, Edmonton (Canada). Northern Forestry Centre

    2002-06-01

    Species composition, detritus, and soil data from 97 boreal forest stands along a transect in central Canada were analysed using Correspondence Analysis to determine the dominant environmental/site variables that differentiate these forest stands. Picea mariana stands were densely clustered together on the understorey DCA plot, suggesting a consistent understorey species composition (feather mosses and Ericaceae), whereas Populus tremuloides stands had the most diverse understorey species composition (ca. 30 species, mostly shrubs and herbs). Pinus banksiana stands had several characteristic species of reindeer lichens (Cladina spp.), but saplings and Pinus seedlings were rare. Although climatic variables showed large variation along the transect, the CCA results indicated that site conditions are more important in determining species composition and differentiating the stand types. Forest floor characteristics (litter and humus layer, woody debris, and drainage) appear to be among the most important site variables. Stands of Picea had significantly higher average carbon (C) densities in the combined litter and humus layer (43,530 kg-C/ha) than either Populus (25,500 kg-C/ha) or Pinus (19,400 kg-C/ha). The thick surface organic layer in lowland Picea stands plays an important role in regulating soil temperature and moisture, and organic-matter decomposition, which in turn affect the ecosystem C-dynamics. During forest succession after a stand-replacing disturbance (e.g. fires), tree biomass and surface organic layer thickness increase in all stand types as forests recover; however, woody biomass detritus first decreases and then increases after ca. 80 yr. Soil C densities show slight decrease with ages in Populus stands, but increase in other stand types. These results indicate the complex C-transfer processes among different components (tree biomass, detritus, forest floor, and soil) of boreal ecosystems at various stages of succession.

  10. Burial fluxes and sources of organic carbon in sediments of the central Yellow Sea mud area over the past 200 years

    Institute of Scientific and Technical Information of China (English)

    YANG Shu; YANG Qian; LIU Sai; CAI Deling; QU Keming; SUN Yao

    2015-01-01

    Long-term changes of composition, sources and burial fluxes of TOC (total organic carbon) in sediments of the central Yellow Sea mud area and their possible affecting factors are discussed in this paper. Firstly, similarity analysis is employed to confirm that the carbon burial features resulted from two collected cores are typical in the central Yellow Sea mud area where YSWC (Yellow Sea Warm Current) is prevalent. On this basis, the burial flux of TOC here was considered to be 235.5–488.4 μmol/(cm2∙a) since the first industrial revolution, accounting for about 70%–90% among burial fluxes of TC (total carbon) in the sediments. Compared TOC/TC ratio in the two cores with that in other marine sediments worldwide, we suggest that the growth of calcareous/non-calcareous organisms and dissolution of IC (inorganic carbon) are important factors controlling the TOC/TC ratio in sediment. Results of two-end mixed model based onδ13C data indicate that marine-derived organic carbon (OCa) is the main part among total burial organic carbon which accounts for a ratio over 85%. Due to the high TOC/TC ratio in the two cores, TC in the sediments also mainly exists as OCa, and the proportion of OCa is about 60%–80%. Away from the shore and relatively high primary production in upper waters are the main reasons that OCa is predominant among all burial OC in sediments of the central Yellow Sea mud area. Burial of OC in this mud area is probably mainly influenced by the human activities. Although the economic development during the late 19th century caused by the first industrial revolution in China did not obviously increase the TOC burial fluxes in the sediments, the rise of industry and agriculture after the founding of new China has clearly increased the TOC burial flux since 1950s. Otherwise, we also realize that among TC burial fluxes, TIC account for about 10%–30% in sediments of the central Yellow Sea mud area, so its burial could not be simply ignored here

  11. Record of carbonate preservation and the Mid-Brunhes climatic shift from a seamount top with low sedimentation rates in the Central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Nath, B.N.; Sijinkumar, A.V.; Borole, D.V.; Gupta, S.M.; Mergulhao, L.P.; Mascarenhas-Pereira, M.B.L.; Ramaswamy, V.; Guptha, M.V.S.; Possnert, G.; Aldahan, A.; Khadge, N.H.; Sharma, R.

    ): palaeoceanographic implications. Paleogeography, Paleoclimatology, Paleoecology 196, 409-426. Flynn, W. W. 1968: The determination of low levels of polonium-210 in environmental samples. Analytica Chimica Acta 43, 221-227. Folk, R. L. 1968: Petrology....42(3); 2013; 762-778 Record of carbonate preservation and Mid-Brunhes climatic shift from a seamount top with low sedimentation rates in the Central Indian Basin BEJUGAM NAGENDER NATH, ADUKKAM V. SIJINKUMAR, DNYANDEV V. BOROLE, SHYAM M. GUPTA...

  12. Genome-wide meta-analysis of homocysteine and methionine metabolism identifies five one carbon metabolism loci and a novel association of ALDH1L1 with ischemic stroke.

    Directory of Open Access Journals (Sweden)

    Stephen R Williams

    2014-03-01

    Full Text Available Circulating homocysteine levels (tHcy, a product of the folate one carbon metabolism pathway (FOCM through the demethylation of methionine, are heritable and are associated with an increased risk of common diseases such as stroke, cardiovascular disease (CVD, cancer and dementia. The FOCM is the sole source of de novo methyl group synthesis, impacting many biological and epigenetic pathways. However, the genetic determinants of elevated tHcy (hyperhomocysteinemia, dysregulation of methionine metabolism and the underlying biological processes remain unclear. We conducted independent genome-wide association studies and a meta-analysis of methionine metabolism, characterized by post-methionine load test tHcy, in 2,710 participants from the Framingham Heart Study (FHS and 2,100 participants from the Vitamin Intervention for Stroke Prevention (VISP clinical trial, and then examined the association of the identified loci with incident stroke in FHS. Five genes in the FOCM pathway (GNMT [p = 1.60 × 10(-63], CBS [p = 3.15 × 10(-26], CPS1 [p = 9.10 × 10(-13], ALDH1L1 [p = 7.3 × 10(-13] and PSPH [p = 1.17 × 10(-16] were strongly associated with the difference between pre- and post-methionine load test tHcy levels (ΔPOST. Of these, one variant in the ALDH1L1 locus, rs2364368, was associated with incident ischemic stroke. Promoter analyses reveal genetic and epigenetic differences that may explain a direct effect on GNMT transcription and a downstream affect on methionine metabolism. Additionally, a genetic-score consisting of the five significant loci explains 13% of the variance of ΔPOST in FHS and 6% of the variance in VISP. Association between variants in FOCM genes with ΔPOST suggest novel mechanisms that lead to differences in methionine metabolism, and possibly the epigenome, impacting disease risk. These data emphasize the importance of a concerted effort to understand regulators of one carbon metabolism as potential therapeutic targets.

  13. Genome-wide meta-analysis of homocysteine and methionine metabolism identifies five one carbon metabolism loci and a novel association of ALDH1L1 with ischemic stroke.

    Science.gov (United States)

    Williams, Stephen R; Yang, Qiong; Chen, Fang; Liu, Xuan; Keene, Keith L; Jacques, Paul; Chen, Wei-Min; Weinstein, Galit; Hsu, Fang-Chi; Beiser, Alexa; Wang, Liewei; Bookman, Ebony; Doheny, Kimberly F; Wolf, Philip A; Zilka, Michelle; Selhub, Jacob; Nelson, Sarah; Gogarten, Stephanie M; Worrall, Bradford B; Seshadri, Sudha; Sale, Michèle M

    2014-03-01

    Circulating homocysteine levels (tHcy), a product of the folate one carbon metabolism pathway (FOCM) through the demethylation of methionine, are heritable and are associated with an increased risk of common diseases such as stroke, cardiovascular disease (CVD), cancer and dementia. The FOCM is the sole source of de novo methyl group synthesis, impacting many biological and epigenetic pathways. However, the genetic determinants of elevated tHcy (hyperhomocysteinemia), dysregulation of methionine metabolism and the underlying biological processes remain unclear. We conducted independent genome-wide association studies and a meta-analysis of methionine metabolism, characterized by post-methionine load test tHcy, in 2,710 participants from the Framingham Heart Study (FHS) and 2,100 participants from the Vitamin Intervention for Stroke Prevention (VISP) clinical trial, and then examined the association of the identified loci with incident stroke in FHS. Five genes in the FOCM pathway (GNMT [p = 1.60 × 10(-63)], CBS [p = 3.15 × 10(-26)], CPS1 [p = 9.10 × 10(-13)], ALDH1L1 [p = 7.3 × 10(-13)] and PSPH [p = 1.17 × 10(-16)]) were strongly associated with the difference between pre- and post-methionine load test tHcy levels (ΔPOST). Of these, one variant in the ALDH1L1 locus, rs2364368, was associated with incident ischemic stroke. Promoter analyses reveal genetic and epigenetic differences that may explain a direct effect on GNMT transcription and a downstream affect on methionine metabolism. Additionally, a genetic-score consisting of the five significant loci explains 13% of the variance of ΔPOST in FHS and 6% of the variance in VISP. Association between variants in FOCM genes with ΔPOST suggest novel mechanisms that lead to differences in methionine metabolism, and possibly the epigenome, impacting disease risk. These data emphasize the importance of a concerted effort to understand regulators of one carbon metabolism as potential therapeutic targets.

  14. Report on compounds labelled with nitrogen-13 or carbon-11 used in cancer metabolic studies with quantitative two-dimensional scanning and pet tomography

    International Nuclear Information System (INIS)

    The use of compounds labelled with radionuclides of the elements commonly involved in metabolic processes (oxygen, carbon, nitrogen) is becoming important in the non-invasive study of organ and tumour function. The application of compounds labelled with 13N and 11C to the study of amino-acid metabolism and changes in vasculature following chemotherapy and radiation therapy is described. In particular, 13N-labelled L-glutamate has been found to be useful in visualizing a number of human tumours including osteogenic sarcoma, rhabdomyosarcoma, Ewing's sarcoma, malignant fibrous histiocytoma, pineal gland tumours, primitive neuroectodermal tumours, medulloblastoma and several other solid tumours. In patients with bone tumours, changes in 13N-L-glutamate scans during chemotherapy were found to correlate with changes in other clinical parameters, such as serum alkaline phosphatase, histology and 99Tcsup(m)-bone scans, thus indicating that labelled L-glutamate is potentially useful in evaluating the response of solid tumours to chemotherapy. Scans of patients and volunteers using 13N-L-glutamate and 13N-L-valine indicate that the L-amino acids may be useful in studies of metabolic processes in the liver, myocardium and pancreas. Red blood cells, labelled with 11C-carbon monoxide via inhalation of the radioactive gas, have been used to assess changes in tumour vascularity following radiation therapy. Alpha-aminoisobutyric acid labelled with 11C has been synthesized and its distribution in normal and tumour-bearing dogs has been studied. (author)

  15. Carbon partitioning in Arabidopsis thaliana is a dynamic process controlled by the plants metabolic status and its circadian clock

    OpenAIRE

    Kölling, Katharina; Thalmann, Matthias; Müller, Antonia; Jenny, Camilla; Zeeman, Samuel C.

    2015-01-01

    Abstract Plant growth involves the coordinated distribution of carbon resources both towards structural components and towards storage compounds that assure a steady carbon supply over the complete diurnal cycle. We used 14CO2 labelling to track assimilated carbon in both source and sink tissues. Source tissues exhibit large variations in carbon allocation throughout the light period. The most prominent change was detected in partitioning towards starch, being low in the morning and more than...

  16. Risk of Visual Impairment and Intracranial Hypertension After Space Flight: Evaluation of the Role of Polymorphism of Enzymes Involved in One-Carbon Metabolism

    Science.gov (United States)

    Smith, S. M.; Gregory, J. F.; Zeisel, G. H.; Gibson, C. R.; Mader, T. H.; Kinchen, J.; Ueland, P.; Ploutz-Snyder, R.; Heer, M.; Zwart, S. R.

    2016-01-01

    Data from the Nutritional Status Assessment protocol provided biochemical evidence that the one-carbon metabolic pathway may be altered in individuals experiencing vision-related issues during and after space flight (1, 2). Briefly, serum concentrations of homocysteine, cystathionine, 2-methylcitric acid, and methylmalonic acid were significantly (Penzymes in the one-carbon pathway, and to evaluate how these relate to vision and other medical aspects of the eye. Specifically, we investigated 5 polymorphisms in MTRR, MTHFR, SHMT, and CBS genes and their association with ophthalmic changes after flight in 49 astronauts. The number of G alleles of MTRR 66 and C alleles of SHMT1 1420 both contributed to the odds of visual disturbances (3). Block regression showed that B-vitamin status at landing and genetics were significant predictors for many of the ophthalmic outcomes studied (3). In conclusion, we document an association between MTRR 66 and SHMT1 1420 polymorphisms and space flightinduced vision changes. These data document that individuals with an altered 1-carbon metabolic pathway may be predisposed to anatomic and/or physiologic changes that render them susceptible to ophthalmic damage during space flight.

  17. Carbon-flux distribution within Streptomyces coelicolor metabolism: a comparison between the actinorhodin-producing strain M145 and its non-producing derivative M1146.

    Directory of Open Access Journals (Sweden)

    Fabien Coze

    Full Text Available Metabolic Flux Analysis is now viewed as essential to elucidate the metabolic pattern of cells and to design appropriate genetic engineering strategies to improve strain performance and production processes. Here, we investigated carbon flux distribution in two Streptomyces coelicolor A3 (2 strains: the wild type M145 and its derivative mutant M1146, in which gene clusters encoding the four main antibiotic biosynthetic pathways were deleted. Metabolic Flux Analysis and (13C-labeling allowed us to reconstruct a flux map under steady-state conditions for both strains. The mutant strain M1146 showed a higher growth rate, a higher flux through the pentose phosphate pathway and a higher flux through the anaplerotic phosphoenolpyruvate carboxylase. In that strain, glucose uptake and the flux through the Krebs cycle were lower than in M145. The enhanced flux through the pentose phosphate pathway in M1146 is thought to generate NADPH enough to face higher needs for biomass biosynthesis and other processes. In both strains, the production of NADPH was higher than NADPH needs, suggesting a key role for nicotinamide nucleotide transhydrogenase for redox homeostasis. ATP production is also likely to exceed metabolic ATP needs, indicating that ATP consumption for maintenance is substantial.Our results further suggest a possible competition between actinorhodin and triacylglycerol biosynthetic pathways for their common precursor, acetyl-CoA. These findings may be instrumental in developing new strategies exploiting S. coelicolor as a platform for the production of bio-based products of industrial interest.

  18. 致病菌碳源代谢与毒力调控的关联性%Correlation between carbon metabolism and virulence regulation in pathogen

    Institute of Scientific and Technical Information of China (English)

    周妍妍; 阚飙

    2012-01-01

    在自然环境中,细菌需要应对生长环境的不断变化.细菌发展了一些机制以适应这些环境的变化.其中,对可用碳源的适应性机制是其中的重要方面.碳源是细菌对复杂环境作出适应反应的信号之一,某种特定碳源的出现也许使细菌感受到正处于感染相关的机体组织或细胞中,从而促使毒力基因表达.本文简述了细菌对可用碳源的适应性机制,并就致病菌碳源代谢与毒力调控的关联性进行了综述.这些致病菌主要包括了硬壁菌门的链球菌、单增李斯特菌、产气夹膜杆菌;变形菌门的牛种布鲁氏杆菌、脑膜炎奈瑟氏菌、鼠伤寒沙门氏菌、霍乱弧菌、根瘤菌;以及放线茵门的结核分枝杆菌,它们的碳源代谢通过多种途径,如HprK/P及PTS蛋白、CRP-cAMP、ABC转运系统、双组分系统等,影响其毒力表达.%In the natural environment, bacterium develop some mechanisms, especially the mechanism of carbon metabolism for adapting to changes in growth conditions. Since the carbon source serve as signal for environment fitness, the presence of some specific carbon source makes bacteria realizing that they have gained access to the infection-related host and then turning on or switching off expression of the specific virulence genes. In the review, we will briefly summarize the mechanisms used for responding to carbon source availability, and review the resent progress about the relation between carbon metabolism and virulence regulation in pathogen. The pathogens mentioned here mainly include the Streptococcus, Listeria monocytogenes, Clostridium perfringens in Firmicutes, Brucella abortus, Neisseria meningitidis, Salmonella Typhimurium, Vibrio chol-erae, Agrobacterium tumefaciens in Proteobacteria, and Mycobacterium tuberculosis in Actinobacteria . The virulence regulation could be affected by carbon metabolism through HprK/P, PTS proteins, CRP-cAMP, ATP-binding cassette transporters, two

  19. A Functional Screen for Myc-Responsive Genes Reveals Serine Hydroxymethyltransferase, a Major Source of the One-Carbon Unit for Cell Metabolism

    Science.gov (United States)

    Nikiforov, Mikhail A.; Chandriani, Sanjay; O'Connell, Brenda; Petrenko, Oleksi; Kotenko, Iulia; Beavis, Andrew; Sedivy, John M.; Cole, Michael D.

    2002-01-01

    A cDNA library enriched with Myc-responsive cDNAs but depleted of myc cDNAs was used in a functional screen for growth enhancement in c-myc-null cells. A cDNA clone for mitochondrial serine hydroxymethyltransferase (mSHMT) that was capable of partial complementation of the growth defects of c-myc-null cells was identified. Expression analysis and chromatin immunoprecipitation demonstrated that mSHMT is a direct Myc target gene. Furthermore, a separate gene encoding the cytoplasmic isoform of the same enzyme is also a direct target of Myc regulation. SHMT enzymes are the major source of the one-carbon unit required for folate metabolism and for the biosynthesis of nucleotides and amino acids. Our data establish a novel functional link between Myc and the regulation of cellular metabolism. PMID:12138190

  20. Mass concentrations of black carbon measured by four instruments in the middle of Central East China in June 2006

    Directory of Open Access Journals (Sweden)

    Y. Kanaya

    2008-08-01

    Full Text Available Mass concentrations of black carbon (BC were determined in June 2006 at the top of Mount Tai (36.26° N, 117.11° E, 1534 m a.s.l., located in the middle of Central East China, using four different instruments: a multi-angle absorption photometer (5012 MAAP, Thermo, a particle soot absorption photometer (PSAP, Radiance Research, an ECOC semi-continuous analyzer (Sunset Laboratory and an Aethalometer (AE-21, Magee Scientific. High correlation coefficients (R2>0.88 were obtained between the measurements of the BC mass concentrations by the different instruments. From the range of the slopes of the linear least-square fittings, we concluded that the BC concentrations regionally-representative of the area were measured in a range with a maximum-to-minimum ratio of 1.5 (an exception was that the BC (PM2.5 concentrations derived from MAAP were ~2 times higher than the optical measurements (PM2.5 derived from the ECOC analyzer. This range is significant, but is still sufficiently narrow to better constrain the large and highly uncertain emission rate of BC from China. In detail, two optical instruments (the MAAP instrument and the PSAP instrument equipped with a heated inlet (400°C tended to give higher concentrations than the thermal EC concentrations observed by the ECOC analyzer. The ratios of optical BC to thermal EC showed a positive correlation with the OC/EC ratio reported by the ECOC analyzer, suggesting two possibilities. One is that the optical instruments overestimated BC concentrations in spite of careful cancellation of the scattering effect in the MAAP instrument and the expected evaporation of volatile species by heating the inlet of the PSAP instrument. The other is that the determined split points between OC and EC were too late when a large amount of OC underwent charring during the analysis, resulting in an underestimation of EC by the ECOC analyzer. High ratios of optical BC to thermal EC

  1. Physical and biological controls on the carbonate chemistry of coral reef waters: effects of metabolism, wave forcing, sea level, and geomorphology.

    Directory of Open Access Journals (Sweden)

    James L Falter

    Full Text Available We present a three-dimensional hydrodynamic-biogeochemical model of a wave-driven coral-reef lagoon system using the circulation model ROMS (Regional Ocean Modeling System coupled with the wave transformation model SWAN (Simulating WAves Nearshore. Simulations were used to explore the sensitivity of water column carbonate chemistry across the reef system to variations in benthic reef metabolism, wave forcing, sea level, and system geomorphology. Our results show that changes in reef-water carbonate chemistry depend primarily on the ratio of benthic metabolism to the square root of the onshore wave energy flux as well as on the length and depth of the reef flat; however, they are only weakly dependent on channel geometry and the total frictional resistance of the reef system. Diurnal variations in pCO(2, pH, and aragonite saturation state (Ω(ar are primarily dependent on changes in net production and are relatively insensitive to changes in net calcification; however, net changes in pCO(2, pH, and Ω(ar are more strongly influenced by net calcification when averaged over 24 hours. We also demonstrate that a relatively simple one-dimensional analytical model can provide a good description of the functional dependence of reef-water carbonate chemistry on benthic metabolism, wave forcing, sea level, reef flat morphology, and total system frictional resistance. Importantly, our results indicate that any long-term (weeks to months net offsets in reef-water pCO(2 relative to offshore values should be modest for reef systems with narrow and/or deep lagoons. Thus, the long-term evolution of water column pCO(2 in many reef environments remains intimately connected to the regional-scale oceanography of offshore waters and hence directly influenced by rapid anthropogenically driven increases in pCO(2.

  2. World-Economy Centrality and Carbon Dioxide Emissions: A New Look at the Position in the Capitalist World-System and Environmental Pollution

    Directory of Open Access Journals (Sweden)

    Paul Prew

    2015-08-01

    Full Text Available With the ever-growing concern of climate change, much attention has been paid to the factors driving carbon dioxide emissions. Previous research in the World-Systems perspective has identified a relationship between carbon dioxide emissions and position in the world-economy. This study intends to build on the previous research by developing a new, more parsimonious indicator of World-System position based on Immanuel Wallerstein’s theoretical concepts of incorporation and core-periphery processes. The new World-System indicator is derived from the centrality measure in network analysis based on import data from the International Monetary Fund’s Direction of Trade Statistics. Based on the theoretical concepts of core-periphery processes, carbon dioxide emissions are predicted to rise based on the predominance of energy-intensive, high-technology, core processes within the nation. The results tend to demonstrate a strong relationship between carbon dioxide emissions and position in the world-economy, and the new World-System position indicator is more strongly related with carbon dioxide emissions than Gross Domestic Product per capita.

  3. The CCAAT box-binding factor stimulates ammonium assimilation in Saccharomyces cerevisiae, defining a new cross-pathway regulation between nitrogen and carbon metabolisms.

    OpenAIRE

    Dang, V D; Bohn, C.; Bolotin-Fukuhara, M.; Daignan-Fornier, B

    1996-01-01

    In Saccharomyces cerevisiae, carbon and nitrogen metabolisms are connected via the incorporation of ammonia into glutamate; this reaction is catalyzed by the NADP-dependent glutamate dehydrogenase (NADP-GDH) encoded by the GDH1 gene. In this report, we show that the GDH1 gene requires the CCAAT box-binding activator (HAP complex) for optimal expression. This conclusion is based on several lines of evidence: (1) overexpression of GDH1 can correct the growth defect of hap2 and hap3 mutants on a...

  4. Subaerial exposure and drowning processes in a carbonate platform during the Mesozoic Tethyan rifting: The case of the Jurassic succession of Western Sicily (central Mediterranean)

    Science.gov (United States)

    Sulli, A.; Interbartolo, F.

    2016-01-01

    The Liassic carbonate platform succession outcropping at Monte Maranfusa (central Western Sicily) consists of a shallowing-upward sequence of peritidal carbonates, with Jurassic to Paleogene pelagic limestone and siliciclastic Tertiary covers above. The cyclic sequences of subtidal wackestones/packstones, intertidal microcrystalline carbonates with bird's-eye pores, and supratidal bioclastic grainstones are interbedded with dark layers of the following composition: 1) dark-gray, compact, and well-cemented limestone with blackish clasts, interpreted as calcretes (a type of carbonate soil) and 2) reddish calcite laminae, deformed by elongated cavities, filled with vadose silt, interpreted as paleokarst. This succession is crossed by almost vertical faults, of the Late Liassic to Miocene, which often coincides with neptunian dykes, filled by several generations of Toarcian-Early Miocene pelagic sediments. Another system of dykes, known as neptunian sills, filled by injected Upper Lias-Dogger pelagic sediments, lies parallel to the stratification. The parallel dykes were caused by the flexure of the platform during the Jurassic and presumably by a planar slip in the carbonate rocks, whereas neptunian dykes are caused by faulting episodes. Here, we present evidence that the dark layers in the Liassic succession of Monte Maranfusa, previously described by many authors only as parallel dykes, can actually be interpreted as a) neptunian sills, b) pedogenic calcretes, and c) paleospeleothems. Therefore, we found evidence of exposure/flooding intervals in the evolution of the carbonate platform during the Liassic, linked to different pulses in both the subsidence/tectonic activity and the sea-level oscillations. At the top, Fe-Mn crusts (hardgrounds) seal the carbonate platform succession, which is in turn overlain by condensed pelagic deposits, confirming its drowning during rifting processes.

  5. Impact of total organic carbon (in sediments) and dissolved organic carbon (in overlying water column) on Hg sequestration by coastal sediments from the central east coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Chakrabortya, P.; Sharma, B.M.; Babu, P.V.R.; Yao, K.M.; Jaychandran, S.

          1.0 Introduction Mercury (Hg) has received a worldwide attention due to its significant global adverse impact on both environment and human health (Boening, 2000; Ratcliffe et al., 1996; Wolfe et al., 2009). Due to its high toxicity... of dissolved organic carbon and salinity on bioavailability of mercury. Applied and Environmental Microbiology, 63, 4267–4271. Bengtsson, G., Picado, F., 2008. Mercury sorption to sediments: Dependence on grain size, dissolved organic carbon, and suspended...

  6. Analysis of carbon and nitrogen co-metabolism in yeast by ultrahigh-resolution mass spectrometry applying {sup 13}C- and {sup 15}N-labeled substrates simultaneously

    Energy Technology Data Exchange (ETDEWEB)

    Blank, Lars M. [TU Dortmund University, Laboratory of Chemical Biotechnology, Department of Biochemical and Chemical Engineering, Dortmund (Germany); RWTH Aachen University, Institute of Applied Microbiology - iAMB, Aachen Biology and Biotechnology - ABBt, Aachen (Germany); Desphande, Rahul R. [TU Dortmund University, Laboratory of Chemical Biotechnology, Department of Biochemical and Chemical Engineering, Dortmund (Germany); Michigan State University, Department of Plant Biology, East Lansing, MI (United States); Schmid, Andreas [TU Dortmund University, Laboratory of Chemical Biotechnology, Department of Biochemical and Chemical Engineering, Dortmund (Germany); Hayen, Heiko [Leibniz-Institut fuer Analytische Wissenschaften-ISAS-e.V, Dortmund (Germany); University of Wuppertal, Department of Food Chemistry, Wuppertal (Germany)

    2012-06-15

    Alternative metabolic pathways inside a cell can be deduced using stable isotopically labeled substrates. One prerequisite is accurate measurement of the labeling pattern of targeted metabolites. Experiments are generally limited to the use of single-element isotopes, mainly {sup 13}C. Here, we demonstrate the application of direct infusion nanospray, ultrahigh-resolution Fourier transform ion cyclotron resonance-mass spectrometry (FTICR-MS) for metabolic studies using differently labeled elemental isotopes simultaneously - i.e., {sup 13}C and {sup 15}N - in amino acids of a total protein hydrolysate. The optimized strategy for the analysis of metabolism by a hybrid linear ion trap-FTICR-MS comprises the collection of multiple adjacent selected ion monitoring scans. By limiting both the width of the mass range and the number of ions entering the ICR cell with automated gain control, sensitive measurements of isotopologue distribution were possible without compromising mass accuracy and isotope intensity mapping. The required mass-resolving power of more than 60,000 is only achievable on a routine basis by FTICR and Orbitrap mass spectrometers. Evaluation of the method was carried out by comparison of the experimental data to the natural isotope abundances of selected amino acids and by comparison to GC/MS results obtained from a labeling experiment with {sup 13}C-labeled glucose. The developed method was used to shed light on the complexity of the yeast Saccharomyces cerevisiae carbon-nitrogen co-metabolism by administering both {sup 13}C-labeled glucose and {sup 15}N-labeled alanine. The results indicate that not only glutamate but also alanine acts as an amino donor during alanine and valine synthesis. Metabolic studies using FTICR-MS can exploit new possibilities by the use of multiple-labeled elemental isotopes. (orig.)

  7. Comparison of end-tidal carbon dioxide and arterial blood bicarbonate levels in patients with metabolic acidosis referred to emergency medicine

    Science.gov (United States)

    Taghizadieh, Ali; Pouraghaei, Mahboub; Moharamzadeh, Payman; Ala, Alireza; Rahmani, Farzad; Basiri Sofiani, Karim

    2016-01-01

    Introduction: The routine and gold standard method to diagnose of acid – base disturbance is arterial blood gas (ABG) sampling. Capnography could be used to measure the end-tidal carbon dioxide (ETCO2) levels and ETco2 has a close correlation with the PaCo2. The aim of this study was comparison the ETco2 and arterial blood bicarbonate levels in patients with metabolic acidosis. Methods: In a descriptive-analytical study that performed in Emergency Department of Emam Reza Medical Research and Training Hospital of Tabriz on patients with metabolic acidosis, ETco2 level and blood bicarbonate levels in 262 patients were evaluated. Results: Mean of ETco2 and Hco3 levels in patients with metabolic acidosis were 22.29 ± 4.15 and 12.78 ± 3.83, respectively. In all patients, the significant direct linear relationship was found between ETco2 with Hco3 (r = 0.553, P < 0.001). We had 4 groups of patients with metabolic acidosis, also there is a significant direct linear relationship between the ETCo2 and the Hco3 level of arterial blood in patients with renal failure (P < 0.001 and r = 0.551), sepsis (P < 0.001 and r = 0.431), drug toxicity (P < 0.001 and r = 0.856), and ketoacidosis (DKA) (P < 0.001 and r = 0.559). Conclusion: According to the results of this study, capnography can be used for primary diagnosis of metabolic acidosis in spontaneously breathing patients who referred to the emergency wards, however, the ABG must be considered as the gold standard tool for diagnosis and guiding the treatment. PMID:27777693

  8. POSSIBLE LATE MIDDLE ORDOVICIAN ORGANIC CARBON ISOTOPE EXCURSION: EVIDENCE FROM ORDOVICIAN OILS AND HYDROCARBON SOURCE ROCKS, MID-CONTINENT AND EAST-CENTRAL UNITED STATES.

    Science.gov (United States)

    Hatch, Joseph R.; Jacobson, Stephen R.; Witzke, Brian J.; Risatti, J. Bruno; Anders, Donald E.; Watney, W. Lynn; Newell, K. David; Vuletich, April K.

    1987-01-01

    Oils generated by Middle Ordovician rocks are found throughout the Mid-Continent and east-central regions of the United States. Gas chromatographic characteristics of these oils include a relatively high abundance of n-alkanes with carbon numbers less than 20, a strong predominance of odd-numbered n-alkanes between C//1//0 and C//2//0, and relatively small amounts of branched and cyclic alkanes. The wide ranges in delta **1**3C for oils and rock extracts reflect a major, positive excursion(s) in organic matter delta **1**3C in late Middle Ordovician rocks. This excursion has at least regional significance in that it can be documented in sections 480 mi apart in south-central Kansas and eastern Iowa. The distance may be as much as 930 mi. The parallel shifts in organic and carbonate delta **1**3C in core samples from 1 E. M. Greene well, Washington County, Iowa, imply changes in the isotope composition of the ocean-atmosphere carbon reservoir. These and other aspects of the subject are discussed.

  9. Measuring and modeling C flux rates through the central metabolic pathways in microbial communities using position-specific 13C-labeled tracers

    Science.gov (United States)

    Dijkstra, P.; van Groenigen, K.; Hagerty, S.; Salpas, E.; Fairbanks, D. E.; Hungate, B. A.; KOCH, G. W.; Schwartz, E.

    2012-12-01

    The production of energy and metabolic precursors occurs in well-known processes such as glycolysis and Krebs cycle. We use position-specific 13C-labeled metabolic tracers, combined with models of microbial metabolic organization, to analyze the response of microbial community energy production, biosynthesis, and C use efficiency (CUE) in soils, decomposing litter, and aquatic communities. The method consists of adding position-specific 13C -labeled metabolic tracers to parallel soil incubations, in this case 1-13C and 2,3-13C pyruvate and 1-13C and U-13C glucose. The measurement of CO2 released from the labeled tracers is used to calculate the C flux rates through the various metabolic pathways. A simplified metabolic model consisting of 23 reactions is solved using results of the metabolic tracer experiments and assumptions of microbial precursor demand. This new method enables direct estimation of fundamental aspects of microbial energy production, CUE, and soil organic matter formation in relatively undisturbed microbial communities. We will present results showing the range of metabolic patterns observed in these communities and discuss results from testing metabolic models.

  10. Interactions between carbon metabolism and the uptake and assimilation of inorganic nitrogen in Ankistrodesmus falcatus (Corda) Ralfs

    International Nuclear Information System (INIS)

    Nitrate uptake in nitrogen-limited Ankistrodesmus falcatus (Corba) Ralfs was found to be directly dependent on: (1) nitrate concentration; (2) the availability of carbon dioxide or recently synthesised carbon skeletons; (3) light intensity and (4) the presence of ammonium or metabolites of ammonium assimilation. Nitrate uptake was found to obey simple Michaelis-Menten kinetics. In the absence of carbon dioxide, nitrate uptake was destabilised and resulted in nitrate efflux from the cells. If the cells were pre-adapted to high levels of carbon dioxide, a decrease in the concentration of supplied carbon dioxide resulted in only a transient suppression of nitrate uptake. These results indicate that carbon dioxide was required for the stabilisation of the nitrate uptake system and that nitrate uptake, reduction and assimilation could proceed if supplies of recently synthesised carbon skeletons were available for subsequent ammonium incorporation into amino acids. It was concluded that the mobilisation of storage carbohydrate could provide the necessary reducing potential and ATP for nitrate uptake. The addition of ammonium to A. falcatus cells accumulating nitrate resulted in the immediate cessation of nitrate uptake and subsequent nitrate efflux from the cells. Assays of nitrate reductase activity indicated that the activity of the enzyme increased under nitrogen-limitation. Nitrogen-limited, nitrate-growth and ammonium-grown cultures of A. falcatus were used to determine the effects of nitrate and ammonium addition on photosynthetic oxygen exchange, carbon fixation and the path of carbon flow. The addition of these species of inorganic nitrogen resulted in the suppression of photosynthetic oxygen evolution and carbon fixation. Labelling with 14C was used during the carbon fixation studies

  11. Compound specific isotopic fractionation patterns suggest different carbon metabolisms among Chloroflexus-like bacteria in hot spring microbial mats

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Meer, M.T.J. van der; Schouten, S.; Leeuw, J.W. de; Ward, D.M.

    2003-01-01

    Stable carbon isotope fractionations between dissolved inorganic carbon and lipid biomarkers suggest photoautotrophy by Chloroflexus-like organisms in sulfidic and nonsulfidic Yellowstone hot springs. Where co-occurring, cyanobacteria appear to cross-feed Chloroflexus-like organisms supporting photo

  12. Expression and activity of carbonic anhydrase IX is associated with metabolic dysfunction in MDA-MB-231 breast cancer cells.

    NARCIS (Netherlands)

    Li, Ying; Wang, H.; Oosterwijk, E.; Tu, C.; Shiverick, K.T.; Silverman, D.N.; Frost, S.C.

    2009-01-01

    The expression of carbonic anhydrase IX (CAIX), a marker for hypoxic tumors, is correlated with poor prognosis in breast cancer patients. We show herein that the MDA-MB-231 cells, a "triple-negative," basal B line, express exclusively CAIX, while a luminal cell line (T47D) expresses carbonic anhydra

  13. Optimal flux patterns in cellular metabolic networks

    Energy Technology Data Exchange (ETDEWEB)

    Almaas, E

    2007-01-20

    The availability of whole-cell level metabolic networks of high quality has made it possible to develop a predictive understanding of bacterial metabolism. Using the optimization framework of flux balance analysis, I investigate metabolic response and activity patterns to variations in the availability of nutrient and chemical factors such as oxygen and ammonia by simulating 30,000 random cellular environments. The distribution of reaction fluxes is heavy-tailed for the bacteria H. pylori and E. coli, and the eukaryote S. cerevisiae. While the majority of flux balance investigations have relied on implementations of the simplex method, it is necessary to use interior-point optimization algorithms to adequately characterize the full range of activity patterns on metabolic networks. The interior-point activity pattern is bimodal for E. coli and S. cerevisiae, suggesting that most metabolic reaction are either in frequent use or are rarely active. The trimodal activity pattern of H. pylori indicates that a group of its metabolic reactions (20%) are active in approximately half of the simulated environments. Constructing the high-flux backbone of the network for every environment, there is a clear trend that the more frequently a reaction is active, the more likely it is a part of the backbone. Finally, I briefly discuss the predicted activity patterns of the central-carbon metabolic pathways for the sample of random environments.

  14. An assessment on in-vehicle concentration of carbon monoxide for taxis in central business district of Tehran

    Directory of Open Access Journals (Sweden)

    Nabi ollah Mansouri

    2013-01-01

    Full Text Available Background and Aim: Carbon monoxide is colorless and odorless gas. In high concentrations, CO is deadly poisonous and in low concentrations can cause fatigue, headache, dizziness and seizures. Carbon monoxide has a high affinity to combines hemoglobin which can decrease oxygen capacity in blood. To address this problem, human body begins to produce red blood cells, this can increases blood viscosity and thus increase diseases such as stroke and heart attack. About 60 percent of total emissions of carbon monoxide are associated automobile exhaust. In this study, concentration of carbon monoxide has been measured in the cabin space of taxis in high-traffic areas of Tehran.Materials and Methods: This study is carried out in spring and summer 2011. Concentrations of carbon monoxide in different types of taxi cabin space (Peugeot, Samand, Pride and Peykan were measured by carbon monoxide meter Q RAE 2 models in different conditions of motion: high speed (over 45 kilometers per hour, low speed (15-30 kilometers per hour and stop (0 kilometers per hour. Results: Results showed that concentration of carbon monoxide in old vehicles (above 10 years is more than three times compared to new vehicles and outdoor. In addition, according to the measured values, at low speeds, values of CO rapidly increased, so that in speeds of less than 15 km, values of CO go beyond standard values (9 ppm.Conclusion: Results show that the mean value of the measured concentration of carbon monoxide is higher than amounts recommended by WHO and EPA and local authorities such as Air Quality Control Organization of Tehran. Concentrations observed in this study are up to 40 more than results of a study by German researchers in summer 1995 and winter 1996.

  15. Progress on photosynthetic carbon metabolism types in marine macroalgae%大型海藻光合碳代谢类型的研究进展

    Institute of Scientific and Technical Information of China (English)

    芦笛

    2013-01-01

    As a part of marine algae, marine macroalgae, whose edible and medicinal values are widely applied, participate in global CO2 and O2 turnover through photosynthesis. Therefore, when viewed from ecology as well as economics, the process of photosynthetic CO2 fixation and metabolism in marine macroalgae is of great significance. Up to the present, metabonomics and enzymology researches on photosynthetic carbon metabolism in marine macroalgae have proved the existence of the PEPCK-or PEPC-type C4 pathway as well as the CAM pathway in addition to the C3 pathway, although the integrality of the pathways is still unknown. Moreover, the results of photosynthetic gas exchange indicate that the photosynthetic carbon metabolism pathway in macroalgae performs the C4-like type on the whole. This situation resembles some terrestrial C3 plants with additional C4 pathway. Therefore, researches on photosynthetic carbon metabolism pathways in macroalgae remain to be explored in depth in the future.%作为海洋藻类的一部分,大型海藻通过光合作用参与了海洋对全球CO2和O2的周转,其食用和药用价值也得到了广泛应用。因此无论从生态还是经济角度来看,研究大型海藻通过光合作用对CO2进行固定和代谢的过程都具有重要意义。到目前为止,世界上对大型海藻光合碳代谢途径的研究从代谢组学和酶学角度证明了大型海藻体内除了C3途径外,还同时存在不能确定完整与否的PEPCK或PEPC类型的C4途径或CAM途径;光合气体交换的结果显示其光合碳代谢途径从整体上表现出类似C4(C4-like)类型。这种情况与一些体内存在C4途径的陆生C3植物相似。因此大型海藻光合碳代谢途径仍然有待深入研究。

  16. Metabolic and Transcriptional Reprogramming in Developing Soybean (Glycine max Embryos

    Directory of Open Access Journals (Sweden)

    Ruth Grene

    2013-05-01

    Full Text Available Soybean (Glycine max seeds are an important source of seed storage compounds, including protein, oil, and sugar used for food, feed, chemical, and biofuel production. We assessed detailed temporal transcriptional and metabolic changes in developing soybean embryos to gain a systems biology view of developmental and metabolic changes and to identify potential targets for metabolic engineering. Two major developmental and metabolic transitions were captured enabling identification of potential metabolic engineering targets specific to seed filling and to desiccation. The first transition involved a switch between different types of metabolism in dividing and elongating cells. The second transition involved the onset of maturation and desiccation tolerance during seed filling and a switch from photoheterotrophic to heterotrophic metabolism. Clustering analyses of metabolite and transcript data revealed clusters of functionally related metabolites and transcripts active in these different developmental and metabolic programs. The gene clusters provide a resource to generate predictions about the associations and interactions of unknown regulators with their targets based on “guilt-by-association” relationships. The inferred regulators also represent potential targets for future metabolic engineering of relevant pathways and steps in central carbon and nitrogen metabolism in soybean embryos and drought and desiccation tolerance in plants.

  17. Up-regulation of carbon metabolism-related glyoxylate cycle and toxin production in Beauveria bassiana JEF-007 during infection of bean bug, Riptortus pedestris (Hemiptera: Alydidae).

    Science.gov (United States)

    Yang, Yi-Ting; Lee, Se Jin; Nai, Yu-Shin; Kim, Sihyeon; Kim, Jae Su

    2016-10-01

    Beauveria bassiana (Bb) is used as an environment-friendly biopesticide. However, the molecular mechanisms of Bb-host interactions are not well understood. Herein, RNA isolated from B. bassiana (Bb JEF-007) and Riptortus pedestris (Hemiptera: Alydidae) infected with this strain were firstly subjected to high-throughput next generation sequencing (NGS) to analyze and compare transcriptomes. Due to lack of fungal and host genome information, fungal transcriptome was processed to partially exclude non-infection specific genes and host-flora. Differentially Expressed Gene (DEG) analysis showed that 2381 genes were up-regulated and 2303 genes were down-regulated upon infection. Most DEGs were classified into the categories of single-organism, cellular and metabolism processes by Gene Ontology analysis. Most DEGs were involved in metabolic pathways based on Kyoto Encyclopedia of Genes and Genomes pathway mapping. Carbon metabolism-related enzymes in the glyoxylate cycle were significantly up-regulated, suggesting a possible role for them in Bb growth in the host. Additionally, transcript levels of several fungal genes were dramatically increased after infection, such as cytotoxic lectin-like protein, bacterial-like toxin, proteins related to cell wall formation, hyphal growth, nutrient uptake, and halogenated compound synthesis. This work provides insight into how entomopathogenic B. bassiana grows in agriculturally harmful bean bug at 6 d post infection. PMID:27647240

  18. Plastidial Glycolytic Glyceraldehyde-3-Phosphate Dehydrogenase Is an Important Determinant in the Carbon and Nitrogen Metabolism of Heterotrophic Cells in Arabidopsis.

    Science.gov (United States)

    Anoman, Armand D; Muñoz-Bertomeu, Jesús; Rosa-Téllez, Sara; Flores-Tornero, María; Serrano, Ramón; Bueso, Eduardo; Fernie, Alisdair R; Segura, Juan; Ros, Roc

    2015-11-01

    This study functionally characterizes the Arabidopsis (Arabidopsis thaliana) plastidial glycolytic isoforms of glyceraldehyde-3-phosphate dehydrogenase (GAPCp) in photosynthetic and heterotrophic cells. We expressed the enzyme in gapcp double mutants (gapcp1gapcp2) under the control of photosynthetic (Rubisco small subunit RBCS2B [RBCS]) or heterotrophic (phosphate transporter PHT1.2 [PHT]) cell-specific promoters. Expression of GAPCp1 under the control of RBCS in gapcp1gapcp2 had no significant effect on the metabolite profile or growth in the aerial part (AP). GAPCp1 expression under the control of the PHT promoter clearly affected Arabidopsis development by increasing the number of lateral roots and having a major effect on AP growth and metabolite profile. Our results indicate that GAPCp1 is not functionally important in photosynthetic cells but plays a fundamental role in roots and in heterotrophic cells of the AP. Specifically, GAPCp activity may be required in root meristems and the root cap for normal primary root growth. Transcriptomic and metabolomic analyses indicate that the lack of GAPCp activity affects nitrogen and carbon metabolism as well as mineral nutrition and that glycerate and glutamine are the main metabolites responding to GAPCp activity. Thus, GAPCp could be an important metabolic connector of glycolysis with other pathways, such as the phosphorylated pathway of serine biosynthesis, the ammonium assimilation pathway, or the metabolism of γ-aminobutyrate, which in turn affect plant development. PMID:26134167

  19. Systemic distribution of single-walled carbon nanotubes in a novel model: alteration of biochemical parameters, metabolic functions, liver accumulation, and inflammation in vivo.

    Science.gov (United States)

    Principi, Elisa; Girardello, Rossana; Bruno, Antonino; Manni, Isabella; Gini, Elisabetta; Pagani, Arianna; Grimaldi, Annalisa; Ivaldi, Federico; Congiu, Terenzio; De Stefano, Daniela; Piaggio, Giulia; de Eguileor, Magda; Noonan, Douglas M; Albini, Adriana

    2016-01-01

    The increasing use of carbon nanotubes (CNTs) in several industrial applications raises concerns on their potential toxicity due to factors such as tissue penetrance, small dimensions, and biopersistence. Using an in vivo model for CNT environmental exposure, mimicking CNT exposition at the workplace, we previously found that CNTs rapidly enter and disseminate in the organism, initially accumulating in the lungs and brain and later reaching the liver and kidneys via the bloodstream in CD1 mice. Here, we monitored and traced the accumulation of single-walled CNTs (SWCNTs), administered systemically in mice, in different organs and the subsequent biological responses. Using the novel in vivo model, MITO-Luc bioluminescence reporter mice, we found that SWCNTs induce systemic cell proliferation, indicating a dynamic response of cells of both bone marrow and the immune system. We then examined metabolic (water/food consumption and dejections), functional (serum enzymes), and morphological (organs and tissues) alterations in CD1 mice treated with SWCNTs, using metabolic cages, performing serum analyses, and applying histological, immunohistochemical, and ultrastructural (transmission electron microscopy) methods. We observed a transient accumulation of SWCNTs in the lungs, spleen, and kidneys of CD1 mice exposed to SWCNTs. A dose- and time-dependent accumulation was found in the liver, associated with increases in levels of aspartate aminotransferase, alanine aminotransferase and bilirubinemia, which are metabolic markers associated with liver damage. Our data suggest that hepatic accumulation of SWCNTs associated with liver damage results in an M1 macrophage-driven inflammation. PMID:27621623

  20. Regulation of Dual Glycolytic Pathways for Fructose Metabolism in Heterofermentative Lactobacillus panis PM1

    OpenAIRE

    Kang, Tae Sun; Korber, Darren R; Tanaka, Takuji

    2013-01-01

    Lactobacillus panis PM1 belongs to the group III heterofermentative lactobacilli that use the 6-phosphogluconate/phosphoketolase (6-PG/PK) pathway as their central metabolic pathway and are reportedly unable to grow on fructose as a sole carbon source. We isolated a variant PM1 strain capable of sporadic growth on fructose medium and observed its distinctive characteristics of fructose metabolism. The end product pattern was different from what is expected in typical group III lactobacilli us...

  1. Metabolic perturbation of an essential pathway: evaluation of a glycine precursor of Coenzyme A

    OpenAIRE

    Rothmann, Michael; Kang, MinJin; Villa, Reymundo; Ntai, Ioanna; La Clair, James J.; Kelleher, Neil L.; Chapman, Eli; Burkart, Michael D.

    2013-01-01

    Pantetheine, and its corresponding disulfide pantethine, play a key role in metabolism as a building block of coenzyme A (CoA), an essential cofactor utilized in ~4% of primary metabolism and central to fatty acid, polyketide, and non-ribosomal peptide synthases. Using a combination of recombinant engineering and chemical synthesis, we demonstrate that the disulfide of N-pantoylglycyl-2-aminoethanethiol (GlyPan), with one carbon deletion from pantetheine, can rescue a mutant E. coli strain MG...

  2. The influence of climate cycles on the water regime and carbonate profile in chernozems of Central European Russia and adjacent territories

    Science.gov (United States)

    Bazykina, G. S.; Ovechkin, S. V.

    2016-04-01

    The influence of long-term "dry" and "wet" climatic cycles on the water regime, hydrological parameters, and carbonate profiles of chernozems in Central European Russia and adjacent territories was studied. The hydrological and carbonate profiles were found to change during the wet cycle. However, the upper part of the hydrological profile is basically unchanging, whereas in its lower part, the number of hydrological horizons and contrast in their moistening decrease in the forest-steppe chernozems and increase in the steppe chernozems. The frequency of through wetting of chernozems increases during the wet cycles. The vertical lithological heterogeneity of the parent material affects the soil moisture status. In the wet climatic cycle, the moisture content above the lithological contact increases resulting in the development of the features of soil hydromorphism. In the carbonate profile, the character of pedofeatures is changing: some carbonate neoformations disappear, while the other ones develop. Possible variations of the periodically percolative water regime were revealed in chernozems. The classification of water regime proposed by A.A. Rode may be updated based on the data obtained during the dry climatic cycle. Rode's hypothesis about cyclic variations in the soil water regime is confirmed.

  3. Relationships among folate, alcohol consumption, gene variants in one-carbon metabolism and p16 INK4a methylation and expression in healthy breast tissues

    Science.gov (United States)

    Llanos, Adana A.; Dumitrescu, Ramona G.; Brasky, Theodore M.; Liu, Zhenhua; Mason, Joel B.; Marian, Catalin; Makambi, Kepher H.; Spear, Scott L.; Kallakury, Bhaskar V.S.; Freudenheim, Jo L.; Shields, Peter G.

    2015-01-01

    p16 INK4a is a tumor suppressor gene, frequently hypermethylated in breast cancer; this epigenetic silencing of p16 INK4a occurs early in carcinogenesis. The risk factors and functional consequences of p16 INK4a methylation are unknown. Alcohol consumption, a breast cancer risk factor, impedes folate metabolism and may thereby alter gene methylation since folate plays a pivotal role in DNA methylation. In a cross-sectional study of 138 women with no history of breast cancer who underwent reduction mammoplasty, we studied breast cancer risk factors, plasma and breast folate concentrations, variation in one-carbon metabolism genes, p16 INK4a promoter methylation and P16 protein expression. Logistic regression was used to estimate multivariable-adjusted odds ratios (OR) and 95% confidence intervals (CI). p16 INK4a methylation was negatively correlated with P16 expression (r = −0.28; P = 0.002). Alcohol consumption was associated with lower breast folate (P = 0.03), higher p16 INK4a promoter methylation (P = 0.007) and less P16 expression (P = 0.002). Higher breast folate concentrations were associated with lower p16 INK4a promoter methylation (P = 0.06). Genetic variation in MTRR (rs1801394) and MTHFD1 (rs1950902) was associated with higher p16 INK4a promoter methylation (OR = 2.66, 95% CI: 1.11–6.42 and OR = 2.72, 95% CI: 1.12–6.66, respectively), whereas variation in TYMS (rs502396) was associated with less P16 protein expression (OR = 0.22, 95% CI: 0.05–0.99). Given that this is the first study to indicate that alcohol consumption, breast folate and variation in one-carbon metabolism genes are associated with p16 INK4a promoter methylation and P16 protein expression in healthy tissues; these findings require replication. PMID:25344837

  4. Expression and Activity of Carbonic Anhydrase IX Is Associated With Metabolic Dysfunction in MDA-MB-231 Breast Cancer Cells

    OpenAIRE

    Ying LI; Wang, Hai; Oosterwijk, Egbert; Tu, Chingkuang; Shiverick, Kathleen T.; Silverman, David N.; Frost, Susan C.

    2009-01-01

    The expression of carbonic anhydrase IX (CAIX), a marker for hypoxic tumors, is correlated with poor prognosis in breast cancer patients. We show herein that the MDA-MB-231 cells, a “triple-negative,” basal B line, express exclusively CAIX, while a luminal cell line (T47D) expresses carbonic anhydrase XII (CAXII). CAIX expression in the basal B cells is both density-and hypoxia-dependent and is correlated with carbonic anhydrase activity. Evidence is provided that CAIX contributes to extracel...

  5. Helicobacter pylori seropositivity's association with markers of iron, 1-carbon metabolism, and antioxidant status among US adults: a structural equations modeling approach.

    Directory of Open Access Journals (Sweden)

    May A Beydoun

    Full Text Available We tested a model in which Helicobacter pylori seropositivity (Hps predicted iron status, which in turn acted as a predictor for markers of 1-C metabolism that were then allowed to predict antioxidant status.National Health and Nutrition Examination Surveys (NHANES 1999-2000 cross-sectional data among adults aged 20-85 y were analyzed (n = 3,055. Markers of Hps, iron status (serum ferritin and transferrin saturation (TS; 1-C metabolism (serum folate (FOLserum, B-12, total homocysteine (tHcy, methylmalonic acid (MMA and antioxidant status (vitamins A and E were entered into a structural equations model (SEM.Predictors of Hps included older age, lower education and income, racial/ethnic groups (lowest among Non-Hispanic Whites, and lifetime cigarette smoking. SEM modeling indicated that Hps had a direct inverse relationship with iron status (combining serum ferritin and TS which in turn was positively related to 1-C metabolites (higher serum folate, B-12 or lower tHcy/MMA that were positively associated with antioxidant status (combining serum vitamins A and E. Another pathway that was found bypassed 1-C metabolites (Hps → Iron_st → Antiox. The sum of all indirect effects from Hps combining both pathways and the other indirect pathways in the model (Hps → Iron_st → OneCarbon; Hps →OneCarbon →Antiox was estimated at β = -0.006±0.003, p<0.05.In sum, of the total effect of H. pylori seropositivity on antioxidant status, two significant indirect pathways through Iron status and 1-Carbon metabolites were found. Randomized controlled trials should be conducted to uncover the concomitant causal effect of H. pylori eradication on improving iron status, folate, B-12 and antioxidant status among H. pylori seropositive individuals.

  6. Assessment of the effects of dobutamine on myocardial blood flow and oxidative metabolism in normal human subjects using nitrogen-13 ammonia and carbon-11 acetate.

    Science.gov (United States)

    Krivokapich, J; Huang, S C; Schelbert, H R

    1993-06-01

    The dual purposes of this study with positron emission tomography were to measure the effects of dobutamine on myocardial blood flow and oxidative metabolism, and to compare carbon-11 (C-11) acetate versus nitrogen-13 (N-13) ammonia in quantitating flow in normal subjects. Flow was quantitated with N-13 ammonia at rest and at peak dobutamine infusion (40 micrograms/kg/min) in 21 subjects. In 11 subjects, oxidative metabolism was also estimated at rest and peak dobutamine infusion using the clearance rate of C-11 acetate, k mono (min-1). A 2-compartment kinetic model was applied to the early phase of the C-11 acetate data to estimate flow. The rest and peak dobutamine rate-pressure products were 7,318 +/- 1,102 and 19,937 +/- 3,964 beats/min/mm Hg, respectively, and correlated well (r = 0.77) with rest and peak dobutamine flows of 0.77 +/- 0.14 and 2.25 ml/min/g determined using N-13 ammonia as a flow tracer. Rest and dobutamine flows estimated with C-11 acetate were highly correlated with those determined with N-13 ammonia (r = 0.92). k mono increased from 0.05 +/- 0.01 to 0.18 +/- 0.02 min-1, and correlated highly with the increase in flows (r = 0.91) and rate-pressure products (r = 0.94). Thus, the increase in cardiac demand associated with dobutamine is highly correlated with an increase in supply and oxidative metabolism. C-11 acetate is a unique tracer that can be used to image both flow and metabolism simultaneously. PMID:8498380

  7. Fructose Alters Intermediary Metabolism of Glucose in Human Adipocytes and Diverts Glucose to Serine Oxidation in the One–Carbon Cycle Energy Producing Pathway

    Directory of Open Access Journals (Sweden)

    Vijayalakshmi Varma

    2015-06-01

    Full Text Available Increased consumption of sugar and fructose as sweeteners has resulted in the utilization of fructose as an alternative metabolic fuel that may compete with glucose and alter its metabolism. To explore this, human Simpson-Golabi-Behmel Syndrome (SGBS preadipocytes were differentiated to adipocytes in the presence of 0, 1, 2.5, 5 or 10 mM of fructose added to a medium containing 5 mM of glucose representing the normal blood glucose concentration. Targeted tracer [1,2-13C2]-d-glucose fate association approach was employed to examine the influence of fructose on the intermediary metabolism of glucose. Increasing concentrations of fructose robustly increased the oxidation of [1,2-13C2]-d-glucose to 13CO2 (p < 0.000001. However, glucose-derived 13CO2 negatively correlated with 13C labeled glutamate, 13C palmitate, and M+1 labeled lactate. These are strong markers of limited tricarboxylic acid (TCA cycle, fatty acid synthesis, pentose cycle fluxes, substrate turnover and NAD+/NADP+ or ATP production from glucose via complete oxidation, indicating diminished mitochondrial energy metabolism. Contrarily, a positive correlation was observed between glucose-derived 13CO2 formed and 13C oleate and doses of fructose which indicate the elongation and desaturation of palmitate to oleate for storage. Collectively, these results suggest that fructose preferentially drives glucose through serine oxidation glycine cleavage (SOGC pathway one-carbon cycle for NAD+/NADP+ production that is utilized in fructose-induced lipogenesis and storage in adipocytes.

  8. Reservoir Characterization for CO2 Sequestration: Assessing the Potential of the Devonian Carbonate Nisku Formation of Central Alberta Caractérisation de réservoir en vue du stockage géologique de CO2 : évaluation du potentiel offert par les carbonates dévoniens de la formation de Nisku, en Alberta central

    OpenAIRE

    Eisinger C.; Jensen J

    2011-01-01

    The Wabamun Lake area of Central Alberta, Canada includes several large CO2 point source emitters, collectively producing more than 30 Mt annually. Previous studies established that deep saline aquifers beneath the Wabamun Lake area have good potential for the large-scale injection and storage of CO2. This study reports on the characterization of the Devonian carbonate Nisku Formation for evaluation as a CO2 repository. Major challenges for characterization included sparse well and seis...

  9. Carbon sequestration in Chir-Pine (Pinus roxburghii Sarg.) forests un-der various disturbance levels in Kumaun Central Himalaya

    Institute of Scientific and Technical Information of China (English)

    Harshit Pant; Ashish Tewari

    2014-01-01

    We studied variations in tree biomass and carbon sequestra-tion rates of Chir Pine (Pinus roxburghii. Sarg.) forest in three categories of forest disturbance, protected, moderately disturbed, and highly dis-turbed. In the first year, total biomass was 14.7 t⋅ha-1 in highly disturbed site, 94.46 t⋅ha-1 in moderately disturbed forest, and 112.0 t⋅ha-1 in pro-tected forest. The soil organic carbon in the top 20 cm of soil ranged from 0.63 to 1.2%. The total rate of carbon sequestration was 0.60 (t/ha)·a-1on the highly disturbed site, 1.03 (t/ha)·a-1 on the moderately disturbed site, and 4.3 (t/ha)·a-1 on the protected site.

  10. Initial Characterization of Carbon Metabolism in Iron Oxidizing Microbial Communities of Acidic Hot Springs in Norris Geyser Basin, Yellowstone National Park

    Science.gov (United States)

    Kreuzer, H. W.; Jennings, R. D.; Whitmore, L.; Inskeep, W. P.; Moran, J.

    2012-12-01

    the organism produces during autotrophic growth, and are conducting isotopic labeling experiments to determine if these compounds serve as substrates for the iron oxide mat communities. However, isotopic analysis of DIC in the springs as well as bulk iron oxide mat definitively show that fixation of DIC by M. yellowstonensis is not the only source of C within the mats. Metagenome analysis of the microbial communities and genome analysis of isolates suggest the presence of heterotrophic metabolic pathways. Indeed, initial labeling experiments demonstrate strong heterotrophic metabolism in the iron oxide mats as well as in M. yellowstonensis. Several potential sources of reduced C are available in the springs, but whether any of these potential substrates actually feed the iron mat communities is yet to be determined. Carbon isotope ratios of the bulk iron mat communities and potential heterotrophic C sources suggest that heterotrophic uptake of these sources, like autotrophy of DIC, is not the only source of C in the system. Identifying the major active carbon pools and potential geochemical and microbial carbon links will illuminate carbon cycling in this system and should provide insights into how energy is transferred from key chemolithotrophic reactions to other components of the microbial system.

  11. Synoptic evaluation of carbon cycling in Beaufort Sea during summer: contrasting river inputs, ecosystem metabolism and air-sea CO2 fluxes

    Science.gov (United States)

    Forest, A.; Coupel, P.; Else, B.; Nahavandian, S.; Lansard, B.; Raimbault, P.; Papakyriakou, T.; Gratton, Y.; Fortier, L.; Tremblay, J.-É.; Babin, M.

    2013-10-01

    The accelerated decline in Arctic sea ice combined with an ongoing trend toward a more dynamic atmosphere is modifying carbon cycling in the Arctic Ocean. A critical issue is to understand how net community production (NCP; the balance between gross primary production and community respiration) responds to changes and modulates air-sea CO2 fluxes. Using data collected as part of the ArcticNet-Malina 2009 expedition in southeastern Beaufort Sea (Arctic Ocean), we synthesize information on sea ice, wind, river, water column properties, metabolism of the planktonic food web, organic carbon fluxes and pools, as well as air-sea CO2 exchange, with the aim of identifying indices of ecosystem response to environmental changes. Data were analyzed to develop a non-steady-state carbon budget and an assessment of NCP against air-sea CO2 fluxes. The mean atmospheric forcing was a mild upwelling-favorable wind (~5 km h-1) blowing from the N-E and a decaying ice cover (600 mg C m-2d-1) over the shelf prior to our survey, (2) freshwater dilution by river runoff and ice melt, and (3) the presence of cold surface waters offshore. Only the Mackenzie River delta and localized shelf areas directly affected by upwelling were identified as substantial sources of CO2 to the atmosphere (>10mmol C m-2d-1). Although generally state.

  12. Synoptic evaluation of carbon cycling in the Beaufort Sea during summer: contrasting river inputs, ecosystem metabolism and air-sea CO2 fluxes

    Science.gov (United States)

    Forest, A.; Coupel, P.; Else, B.; Nahavandian, S.; Lansard, B.; Raimbault, P.; Papakyriakou, T.; Gratton, Y.; Fortier, L.; Tremblay, J.-É.; Babin, M.

    2014-05-01

    The accelerated decline in Arctic sea ice and an ongoing trend toward more energetic atmospheric and oceanic forcings are modifying carbon cycling in the Arctic Ocean. A critical issue is to understand how net community production (NCP; the balance between gross primary production and community respiration) responds to changes and modulates air-sea CO2 fluxes. Using data collected as part of the ArcticNet-Malina 2009 expedition in the southeastern Beaufort Sea (Arctic Ocean), we synthesize information on sea ice, wind, river, water column properties, metabolism of the planktonic food web, organic carbon fluxes and pools, as well as air-sea CO2 exchange, with the aim of documenting the ecosystem response to environmental changes. Data were analyzed to develop a non-steady-state carbon budget and an assessment of NCP against air-sea CO2 fluxes. During the field campaign, the mean wind field was a mild upwelling-favorable wind (~ 5 km h-1) from the NE. A decaying ice cover ( 600 mg C m-2 d-1) over the shelf prior to our survey, (2) freshwater dilution by river runoff and ice melt, and (3) the presence of cold surface waters offshore. Only the Mackenzie River delta and localized shelf areas directly affected by upwelling were identified as substantial sources of CO2 to the atmosphere (> 10 mmol C m-2 d-1). Daily PP rates were generally state.

  13. Metabolic flux analysis of Gluconacetobacter xylinus for bacterial cellulose production.

    Science.gov (United States)

    Zhong, Cheng; Zhang, Gui-Cai; Liu, Miao; Zheng, Xin-Tong; Han, Pei-Pei; Jia, Shi-Ru

    2013-07-01

    Metabolic flux analysis was used to reveal the metabolic distributions in Gluconacetobacter xylinus (CGMCC no. 2955) cultured on different carbon sources. Compared with other sources, glucose, fructose, and glycerol could achieve much higher bacterial cellulose (BC) yields from G. xylinus (CGMCC no. 2955). The glycerol led to the highest BC production with a metabolic yield of 14.7 g/mol C, which was approximately 1.69-fold and 2.38-fold greater than that produced using fructose and glucose medium, respectively. The highest BC productivity from G. xylinus CGMCC 2955 was 5.97 g BC/L (dry weight) when using glycerol as the sole carbon source. Metabolic flux analysis for the central carbon metabolism revealed that about 47.96 % of glycerol was transformed into BC, while only 19.05 % of glucose and 24.78 % of fructose were transformed into BC. Instead, when glucose was used as the sole carbon source, 40.03 % of glucose was turned into the by-product gluconic acid. Compared with BC from glucose and fructose, BC from the glycerol medium showed the highest tensile strength at 83.5 MPa, with thinner fibers and lower porosity. As a main byproduct of biodiesel production, glycerol holds great potential to produce BC with superior mechanical and microstructural characteristics.

  14. Infrared spectral and carbon isotopic characteristics of micro- and macro-diamonds from the Panda kimberlite (Central Slave Craton, Canada)

    Science.gov (United States)

    Melton, G. L.; Stachel, T.; Stern, R. A.; Carlson, J.; Harris, J. W.

    2013-09-01

    One hundred and twenty-one micro-diamonds (Panda kimberlite (Ekati mine, Central Slave Craton, Canada) were analyzed for nitrogen content, nitrogen aggregation state (%B) and platelet and hydrogen peak areas (cm- 2). Micro-diamond nitrogen concentrations range from 2‰, but mostly vary by bearing metasomatic fluid/melt that isotopically evolves as it percolates upward through the lithosphere.

  15. REGIONAL EMISSIONS OF NITRIC OXIDE (NO) AND CARBON DIOXIDE (CO2) IN AGROECOSYSTEMS IN CENTRAL WEST REGION, BRAZIL.

    Science.gov (United States)

    The Central West Region in Brazil has been the focus of intense agricultural expansion since the 1970s and, nowadays, a large area of native cerrado has been converted to agricultural use. The expansion was accompanied by intensive use of fertilizer, irrigation and management pra...

  16. Comparison of carbon uptake estimates from forest inventory and Eddy-Covariance for a montane rainforest in central Sulawesi

    Science.gov (United States)

    Heimsch, Florian; Kreilein, Heiner; Rauf, Abdul; Knohl, Alexander

    2016-04-01

    Rainforests in general and montane rainforests in particular have rarely been studied over longer time periods. We aim to provide baseline information of a montane tropical forest's carbon uptake over time in order to quantify possible losses through land-use change. Thus we conducted a re-inventory of 22 10-year old forest inventory plots, giving us a rare opportunity to quantify carbon uptake over such a long time period by traditional methods. We discuss shortfalls of such techniques and why our estimate of 1.5 Mg/ha/a should be considered as the lower boundary and not the mean carbon uptake per year. At the same location as the inventory, CO2 fluxes were measured with the Eddy-Covariance technique. Measurements were conducted at 48m height with an LI 7500 open-path infrared gas analyser. We will compare carbon uptake estimates from these measurements to those of the more conventional inventory method and discuss, which factors are probably responsible for differences.

  17. Organic carbon isotope and molecular fossil records of vegetation evolution in central Loess Plateau since 450 kyr

    NARCIS (Netherlands)

    Zhou, Bin; Wali, Guzalnur; Peterse, Francien; Bird, Michael I.

    2016-01-01

    Significant uncertainties remain regarding the temporal evolution of natural vegetation during the Quaternary, and drivers of past vegetation change, on the Chinese Loess Plateau (CLP). This study presents analyses of total organic carbon isotopic composition (TOC) and n-alkane ratios (C31/C27) from

  18. LAND-USE CHANGE AND CARBON FLUX BETWEEN 1970S AND 1990S IN CENTRAL HIGHLANDS OF CHIAPAS, MEXICO

    Science.gov (United States)

    We present results of a study in an intensively impacted and highly fragmented landscape in which we apply field-measured carbon (C) density values to land-use/land-cover (LU/LC) statistics to estimate the flux of C between terrestrial ecosystems and the atmosphere from the 1970s...

  19. Soil organic carbon dynamics of improved fallow-maize rotation systems under conventional and no-tillage in Central Zimbabwe

    NARCIS (Netherlands)

    Nyamadzawo, G.; Chikowo, R.; Nyamugafata, P.; Nyamangara, J.; Giller, K.E.

    2008-01-01

    Fallowing increases soil organic carbon (SOC) during the fallowing phase. However, this benefit is lost quickly during the cropping phase. The objective of this study was to evaluate SOC dynamics of an improved fallow-maize rotation under no-tillage (NT) and conventional tillage (CT) from time of fa

  20. Effect of Secondary Cooling Conditions on Solidification Structure and Central Macrosegregation in Continuously Cast High-Carbon Rectangular Billet

    Science.gov (United States)

    Zeng, Jie; Chen, Weiqing

    2015-10-01

    Solidification structures of high carbon rectangular billet with a size of 180 mm × 240 mm in different secondary cooling conditions were simulated using cellular automaton-finite element (CAFE) coupling model. The adequacy of the model was compared with the simulated and the actual macrostructures of 82B steel. Effects of the secondary cooling water intensity on solidification structures including the equiaxed grain ratio and the equiaxed grain compactness were discussed. It was shown that the equiaxed grain ratio and the equiaxed grain compactness changed in the opposite direction at different secondary cooling water intensities. Increasing the secondary cooling water intensity from 0.9 or 1.1 to 1.3 L/kg could improve the equiaxed grain compactness and decrease the equiaxed grain ratio. Besides, the industrial test was conducted to investigate the effect of different secondary cooling water intensities on the center carbon macrosegregation of 82B steel. The optimum secondary cooling water intensity was 0.9 L/kg, while the center carbon segregation degree was 1.10. The relationship between solidification structure and center carbon segregation was discussed based on the simulation results and the industrial test.

  1. Carbon Metabolism of Soil microorganisms at Low Temperatures: Position-Specific 13C Labeled Glucose Reveals the Story

    Science.gov (United States)

    Apostel, C.; Bore, E. K.; Halicki, S.; Kuzyakov, Y.; Dippold, M.

    2015-12-01

    Metabolic pathway activities at low temperature are not well understood, despite the fact that the processes are relevant for many soils globally and seasonally. To analyze soil metabolism at low temperature, isotopomeres of position-specifically 13C labeled glucose were applied at three temperature levels; +5, -5 -20 oC. In additon, one sterilization treatment with sodium azide at +5 oC was also performed. Soils were incubated for 1, 3 and 10 days while soil samples at -20 oC were additionally sampled after 30 days. The 13C from individual molecule position in respired CO2 was quantifed. Incorporation of 13C in bulk soil, extractable microbial biomass by chloroform fumigation extraction (CFE) and cell membranes of different microbial communities classified by 13C phospholipid fatty acid analysis (PLFA) was carried out. Our 13CO2 data showed a dominance of C-1 respiration at +5 °C for treatments with and without sodium azide, but total respiration for sodium azide inhibited treatments increased by 14%. In contrast, at -5 and -20 oC metabolic behavior showed intermingling of preferential respiration of the glucose C-4 and C-1 positions. Therefore, at +5 °C, pentose phosphate pathway activity is a dominant metabolic pathway used by microorganisms to metabolize glucose. The respiration increase due to NaN3 inhibition was attributed to endoenzymes released from dead organisms that are stabilized at the soil matrix and have access to suitable substrate and co-factors to permit their funtions. Our PLFA analysis showed that incorporation of glucose 13C was higher in Gram negative bacteria than other microbial groups as they are most competitive for LMWOS. Only a limited amount of microbial groups maintained their glucose utilizing activity at -5 and -20 °C and they strongly shifted towards a metabolization of glucose via both glycolysis and pentose phosphate pathways indicating both growth and cellular maintenance. This study revealed a remarkable microbial acitivity

  2. Vision Changes after Space Flight Are Related to Alterations in Folate-Dependent One-Carbon Metabolism

    Science.gov (United States)

    Smith, Scott M.; Gibson, C. Robert; Mader, Thomas H.; Ericson, Karen; Ploutz-Snyder, Robert; Heer, Martina; Zwart, Sara R.

    2011-01-01

    About 20% of astronauts on International Space Station missions have developed measurable ophthalmic changes after flight. This study was conducted to determine whether the folate-dependent 1-carbon pathway is altered in these individuals. Data were modeled to evaluate differences between individuals with ophthalmic changes (n=5) and those without them (n=15). We also correlated mean preflight serum concentrations of the 1-carbon metabolites with changes in measured refraction after flight. Serum homocysteine (HCy), cystathionine, 2-methylcitric acid, and methylmalonic acid concentrations were 25%-45% higher (Pvision issues strongly suggests impairment of the folate-dependent 1-carbon transfer pathway. Impairment of this pathway, by polymorphisms, diet or other means, may interact with components of the microgravity environment to influence these pathophysiologic changes. This study was funded by the NASA Human Research Program.

  3. Changes in ecosystem structure related to the type and extent of woody cover alter carbon dynamics and surface energy exchange in central Texas ecosystems.

    Science.gov (United States)

    Litvak, M. E.; Heilman, J.; McInnes, K.; Owens, K.; Kjelgaard, J.; Thijs, A.

    2006-12-01

    Rangeland ecosystems account for almost two thirds the total land area in Texas. Over the past century, heavy livestock grazing and fire suppression coupled with changes in climate have facilitated the expansion of woody species into rangelands throughout the state. Based in part on the assumption that woody species use more water than their herbaceous counterparts, land managers have used a variety of techniques to reduce tree and shrub abundance to combat the loss of forage for cattle. As a result, the structure of rangelands in Texas is complex, characterized by woody vegetation that is patchy in distribution, and continually changing between grassland, savanna and woodland. Despite the large areal extent of Texas rangelands, very little is known about how the observed changes in ecosystem structure impact carbon cycle dynamics and surface energy exchange. To reduce these uncertainties, we explored explicit relationships between structure and function in these ecosystems by comparing tower-based measurements of carbon and water vapor exchange made simultaneously from July 2004-Dec 2005 across three representative land covers in central Texas: open grassland, savanna with 30% Ashe juniper and honey mesquite cover, and closed canopy woodland. Here we report our findings on what impact the type and pattern of woody plant cover has on biological controls and patterns of carbon sequestration, evapotranspiration, and sensitivity to precipitation pulses. Monthly measurements of leaf level gas exchange, soil respiration rates, herbaceous net ecosystem exchange, and sap flow measurements on dominant woody species were used to augment eddy covariance estimates of ecosystem-atmosphere exchange. The addition of woody species significantly increased carbon sequestration in these ecosystems. Net ecosystem production from July 05-Jun 05 in the grassland, savanna and forest ecosystems was -14 g C m-2, -413 g C m-2, -450 g C m-2, respectively. Evapotranspiration was less

  4. Peculiarities of One-Carbon Metabolism in the Strict Carnivorous Cat and the Role in Feline Hepatic Lipidosis

    Directory of Open Access Journals (Sweden)

    Marica Bakovic

    2013-07-01

    Full Text Available Research in various species has indicated that diets deficient in labile methyl groups (methionine, choline, betaine, folate produce fatty liver and links to steatosis and metabolic syndrome, but also provides evidence of the importance of labile methyl group balance to maintain normal liver function. Cats, being obligate carnivores, rely on nutrients in animal tissues and have, due to evolutionary pressure, developed several physiological and metabolic adaptations, including a number of peculiarities in protein and fat metabolism. This has led to specific and unique nutritional requirements. Adult cats require more dietary protein than omnivorous species, maintain a consistently high rate of protein oxidation and gluconeogenesis and are unable to adapt to reduced protein intake. Furthermore, cats have a higher requirement for essential amino acids and essential fatty acids. Hastened use coupled with an inability to conserve certain amino acids, including methionine, cysteine, taurine and arginine, necessitates a higher dietary intake for cats compared to most other species. Cats also seemingly require higher amounts of several B-vitamins compared to other species and are predisposed to depletion during prolonged inappetance. This carnivorous uniqueness makes cats more susceptible to hepatic lipidosis.

  5. Carbon balance at represenative agroecosystems of Central European Russia with different crops assessed by eddy covariance method

    Science.gov (United States)

    Yaroslavtsev, Alexis; Meshalkina, Joulia; Mazirov, Ilya

    2016-04-01

    Despite the fact that in Russia cropland's soils carbon loses 9 time higher than forest's soils ones (Stolbovoi, 2002), agroecosystems were not given sufficient attention and most of the papers are devoted to forestry and natural ecosystems. Carbon balance was calculated at the Precision Farming Experimental Fields of the Russian Timiryazev State Agricultural University, Moscow, Russia, for two agroecosystems with different crops from the same crop rotation studied for 2 years. The experimental site has a temperate and continental climate and situated in south taiga zone with Arable Sod-Podzoluvisols (Albeluvisols Umbric). Vertical fluxes of carbon dioxide were measured with eddy covariance technique, statistical method to measure and calculate turbulent fluxes within atmospheric boundary layers (Burba, 2013). Crop rotation included potato, winter wheat, barley and vetch and oat mix. Two fields of the same crop rotation were studied in 2013-2014. One of the fields (A) was used in 2013 for barley planting (Hordeum vulgare L.). The field B was in 2013 used for planting together vetch (Vicia sativa L.) and oats (Avena sativa L.). Inversely oats and vetch grass mixt was sown in 2014 on field A. Winter wheat was sown on field A in the very beginning of September. On the second field (B) in 2014 winter wheat occurred from under the snow in the phase of tillering, after harvesting it in mid of July, white mustard (Sinapis alba) was sown for green manure. Carbon uptake (NEE negative values) was registered only for the field with winter wheat and white mustard; perhaps because the two crops were cultivated on the field within one growing season. Three other cases showed CO2 emission. Great difference in 82 g C m‑2 per year in NEE between two fields with vetch and oat mix was related to higher difference in grass yields. NEE for barley field was positive during the whole year; considering only the growing season, NEE for barley was 100 g C m‑2 lower and was negative