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Sample records for carbon metabolism unveils

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

    Directory of Open Access Journals (Sweden)

    Nengyi Zhang

    2010-04-01

    Full Text Available 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.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.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. Unveiling the oxidative metabolism of Achatina fulica (Mollusca: Gastropoda) experimentally infected to Angiostrongylus cantonensis (Nematoda: Metastrongylidae).

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    Tunholi-Alves, Vinícius Menezes; Tunholi, Victor Menezes; Garcia, Juberlan; Mota, Esther Maria; Castro, Rosane Nora; Pontes, Emerson Guedes; Pinheiro, Jairo

    2018-06-01

    For the first time, alterations in the oxidative metabolism of Achatina fulica experimentally infected with different parasite loads of Angiostrongylus cantonensis were determined. For this, the hemolymph activities of lactate dehydrogenase (LDH) and hexokinase and the glucose concentrations in the hemolymph, as well as the polysaccharide reserves in the digestive gland and cephalopedal mass, were assessed. Additionally, the contents of some carboxylic acids in the hemolymph of infected and uninfected snails were determined by high-performance liquid chromatography (HPLC), permitting a better understanding of the alterations related to the host's oxidative metabolism. As the main results, activation of oxidative pathways, such as the glycolytic pathway, was demonstrated in response to the increase in the activity of hexokinase. This tendency was confirmed by the decrease in the contents of glucose in the hemolymph of parasitized snails, indicating that the infection by A. cantonensis alters the host's metabolism, and that these changes are strongly influenced by the parasite load. This metabolic scenario was accompanied by activation of the anaerobic fermentative metabolism, indicated not only by an increase in the activity of (LDH), but also by a reduction of the content of pyruvic acid and accumulation of lactic acid in the hemolymph of parasitized snails. In this circumstance, maintenance of the host's redox balance occurs through activation of the fermentative pathways, and LDH plays a central role in this process. Together, the results indicate that A. cantonensis infection induces activation of the anaerobic metabolism of A. fulica, characterized not only by the accumulation of lactic acid, but also by a reduction in the pyruvic acid and oxalic acid contents in the hemolymph of the infected snails.

  3. Unveiling the oxidative metabolism of Rhipicephalus microplus (Acari: Ixodidae) experimentally exposed to entomopathogenic fungi.

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    Tunholi-Alves, Vinícius Menezes; Tunholi Alves, Victor Menezes; da Silva, Jairo Pinheiro; Nora Castro, Rosane; Salgueiro, Fernanda Barbosa; Perinotto, Wendell Marcelo de Souza; Gôlo, Patrícia Silva; Camargo, Mariana Guedes; Angelo, Isabele da Costa; Bittencourt, Vânia Rita Elias Pinheiro

    2016-10-01

    Rhipicephalus microplus is an important tick in tropical regions due to the high economic losses caused by its parasitism. Metarhizium anisopliae and Beauveria bassiana are well-known entomopathogenic fungi that can afflict R. microplus ticks. The development of new targets and strategies to control this parasite can be driven by studies of this tick's physiology. Recently, it was reported that when exposed to adverse physiological conditions, ticks can activate fermentative pathways, indicating transition from aerobic to anaerobic metabolism. Nevertheless, the precise mechanism by which entomopathogenic fungi influence R. microplus metabolism has not been clarified, limiting understanding of the tick-fungus association. Thus, the present study aimed to evaluate the effect of infection of ticks by M. anisopliae and B. bassiana on the amount of selected carboxylic acids present in the hemolymph, enabling increased understanding of changes previously reported. The results showed preservation in the concentrations of oxalic, lactic, and pyruvic acids in the hemolymph 24 and 48 h after dropping from cattle; while there were variations in the concentration of these carboxylic acids after infection of female ticks to M. anisopliae and B. bassiana. Significant increases were observed in the concentration of oxalic and lactic acids and significant reduction of pyruvic acid for both observation times (24 and 48 h) after infection by entomopathogenic fungi. These results indicate that B. bassiana and M. anisopliae infection alters the basal metabolism of R. microplus females, resulting in the activation of fermentative pathways.

  4. On the mobility of carbon-supported platinum nanoparticles towards unveiling cathode degradation in water electrolysis

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    Paciok, Paul; Schalenbach, Maximilian; Carmo, Marcelo; Stolten, Detlef

    2017-10-01

    This study investigates the influence of the hydrogen evolution reaction (HER) overpotential on the mobility of carbon-supported platinum particles. The migration of the platinum over the carbon support was analyzed by means of identical location transmission electron microscopy (IL-TEM). While at potentials of 0.1 and 0 V vs. reversible hydrogen electrode (RHE), no changes to the Pt/C material were observed. With a decrease of the overpotential to -0.1 V vs. RHE, an increase in the quantity of migrating platinum particles took place. At -0.2 V vs. RHE, a further rise in the particle migration was observed. The effect of the overpotential on the migration was explained by a higher hydrogen generation rate, the formation of a hydrogen monolayer on the platinum and the resulting changes of the platinum support distance. The mechanisms revealed in this study could describe a relevant source of degradation of PEM water electrolyzers.

  5. Prioritizing Popular Proteins in Liver Cancer: Remodelling One-Carbon Metabolism.

    Science.gov (United States)

    Mora, María Isabel; Molina, Manuela; Odriozola, Leticia; Elortza, Félix; Mato, José María; Sitek, Barbara; Zhang, Pumin; He, Fuchu; Latasa, María Uxue; Ávila, Matías Antonio; Corrales, Fernando José

    2017-12-01

    Primary liver cancer (HCC) is recognized as the fifth most common neoplasm and the second leading cause of cancer death worldwide. Most risk factors are known, and the molecular pathogenesis has been widely studied in the past decade; however, the underlying molecular mechanisms remain to be unveiled, as they will facilitate the definition of novel biomarkers and clinical targets for more effective patient management. We utilize the B/D-HPP popular protein strategy. We report a list of popular proteins that have been highly cocited with the expression "liver cancer". Several enzymes highlight the known metabolic remodeling of liver cancer cells, four of which participate in one-carbon metabolism. This pathway is central to the maintenance of differentiated hepatocytes, as it is considered the connection between intermediate metabolism and epigenetic regulation. We designed a targeted selective reaction monitoring (SRM) method to follow up one-carbon metabolism adaptation in mouse HCC and in regenerating liver following exposure to CCl 4 . This method allows systematic monitoring of one-carbon metabolism and could prove useful in the follow-up of HCC and of chronically liver-diseased patients (cirrhosis) at risk of HCC. The SRM data are available via ProteomeXchange in PASSEL (PASS01060).

  6. Systems biology and genome-wide approaches to unveil the molecular players involved in the pre-germinative metabolism: implications on seed technology traits.

    Science.gov (United States)

    Macovei, Anca; Pagano, Andrea; Leonetti, Paola; Carbonera, Daniela; Balestrazzi, Alma; Araújo, Susana S

    2017-05-01

    The pre-germinative metabolism is among the most fascinating aspects of seed biology. The early seed germination phase, or pre-germination, is characterized by rapid water uptake (imbibition), which directs a series of dynamic biochemical events. Among those are enzyme activation, DNA damage and repair, and use of reserve storage compounds, such as lipids, carbohydrates and proteins. Industrial seedling production and intensive agricultural production systems require seed stocks with high rate of synchronized germination and low dormancy. Consequently, seed dormancy, a quantitative trait related to the activation of the pre-germinative metabolism, is probably the most studied seed trait in model species and crops. Single omics, systems biology, QTLs and GWAS mapping approaches have unveiled a list of molecules and regulatory mechanisms acting at transcriptional, post-transcriptional and post-translational levels. Most of the identified candidate genes encode for regulatory proteins targeting ROS, phytohormone and primary metabolisms, corroborating the data obtained from simple molecular biology approaches. Emerging evidences show that epigenetic regulation plays a crucial role in the regulation of these mentioned processes, constituting a still unexploited strategy to modulate seed traits. The present review will provide an up-date of the current knowledge on seed pre-germinative metabolism, gathering the most relevant results from physiological, genetics, and omics studies conducted in model and crop plants. The effects exerted by the biotic and abiotic stresses and priming are also addressed. The possible implications derived from the modulation of pre-germinative metabolism will be discussed from the point of view of seed quality and technology.

  7. Photosynthetic carbon metabolism in freshwater phytoplankton

    International Nuclear Information System (INIS)

    Groeger, A.W.

    1986-01-01

    Photosynthetic carbon metabolism of natural assemblages of freshwater phytoplankton was measured by following the flow of inorganic 14 C into the photosynthetic end products polysaccharide protein, lipid, and soluble metabolites. Data were collected from a wide range of physical, chemical, and trophic conditions in six southern United States reservoirs, with the primary environmental variables of interest being light intensity and nutrient supply. Polysaccharide and protein were consistently the primary products of photosynthetic carbon metabolism, comprising an average of 70% of the total carbon fixation over a wide range of light intensities. Polysaccharide was quantitatively more important at higher light intensities, and protein at lower light intensities, as light intensity varied both with depth within the water column and over diurnal cycles. Polysaccharide synthesis was more variable over the diurnal period than was protein synthesis. Phytoplankton in the downlake epilimnion of Normandy Lake, a central Tennessee reservoir, responded to summer nitrogen (N) deficiency by increasing relative rates of lipid synthesis from 10-15% to 20-25% of the total photosynthetic carbon fixation. Phytoplankton in more nitrogen-sufficient areas of the reservoir maintained lower rates of lipid synthesis throughout the summer. These results document the occurrence in nature of a relationship between N-deficiency and increased lipid synthesis previously observed only in laboratory algal culture studies

  8. ­Genomic data mining of the marine actinobacteria Streptomyces sp. H-KF8 unveils insights into multi-stress related genes and metabolic pathways involved in antimicrobial synthesis

    Directory of Open Access Journals (Sweden)

    Agustina Undabarrena

    2017-02-01

    Full Text Available Streptomyces sp. H-KF8 is an actinobacterial strain isolated from marine sediments of a Chilean Patagonian fjord. Morphological characterization together with antibacterial activity was assessed in various culture media, revealing a carbon-source dependent activity mainly against Gram-positive bacteria (S. aureus and L. monocytogenes. Genome mining of this antibacterial-producing bacterium revealed the presence of 26 biosynthetic gene clusters (BGCs for secondary metabolites, where among them, 81% have low similarities with known BGCs. In addition, a genomic search in Streptomyces sp. H-KF8 unveiled the presence of a wide variety of genetic determinants related to heavy metal resistance (49 genes, oxidative stress (69 genes and antibiotic resistance (97 genes. This study revealed that the marine-derived Streptomyces sp. H-KF8 bacterium has the capability to tolerate a diverse set of heavy metals such as copper, cobalt, mercury, chromate and nickel; as well as the highly toxic tellurite, a feature first time described for Streptomyces. In addition, Streptomyces sp. H-KF8 possesses a major resistance towards oxidative stress, in comparison to the soil reference strain Streptomyces violaceoruber A3(2. Moreover, Streptomyces sp. H-KF8 showed resistance to 88% of the antibiotics tested, indicating overall, a strong response to several abiotic stressors. The combination of these biological traits confirms the metabolic versatility of Streptomyces sp. H-KF8, a genetically well-prepared microorganism with the ability to confront the dynamics of the fjord-unique marine environment.

  9. Metabolic effects of Carbon Dioxide (CO 2 ) insufflation during ...

    African Journals Online (AJOL)

    Metabolic effects of Carbon Dioxide (CO 2 ) insufflation during laparoscopic surgery: changes in pH, arterial partial Pressure of Carbon Dioxide (PaCo 2 ) and End Tidal Carbon Dioxide (EtCO 2 ) ... Respiratory adjustments were done for EtCO2 levels above 60mmHg or SPO2 below 92% or adverse haemodynamic changes.

  10. A Synthetic Alternative to Canonical One-Carbon Metabolism.

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    Bouzon, Madeleine; Perret, Alain; Loreau, Olivier; Delmas, Valérie; Perchat, Nadia; Weissenbach, Jean; Taran, Frédéric; Marlière, Philippe

    2017-08-18

    One-carbon metabolism is an ubiquitous metabolic pathway that encompasses the reactions transferring formyl-, hydroxymethyl- and methyl-groups bound to tetrahydrofolate for the synthesis of purine nucleotides, thymidylate, methionine and dehydropantoate, the precursor of coenzyme A. An alternative cyclic pathway was designed that substitutes 4-hydroxy-2-oxobutanoic acid (HOB), a compound absent from known metabolism, for the amino acids serine and glycine as one-carbon donors. It involves two novel reactions, the transamination of l-homoserine and the transfer of a one-carbon unit from HOB to tetrahydrofolate releasing pyruvate as coproduct. Since canonical reactions regenerate l-homoserine from pyruvate by carboxylation and subsequent reduction, every one-carbon moiety made available for anabolic reactions originates from CO 2 . The HOB-dependent pathway was established in an Escherichia coli auxotroph selected for prototrophy using long-term cultivation protocols. Genetic, metabolic and biochemical evidence support the emergence of a functional HOB-dependent one-carbon pathway achieved with the recruitment of the two enzymes l-homoserine transaminase and HOB-hydroxymethyltransferase and of HOB as an essential metabolic intermediate. Escherichia coli biochemical reprogramming was achieved by minimally altering canonical metabolism and leveraging on natural selection mechanisms, thereby launching the resulting strain on an evolutionary trajectory diverging from all known extant species.

  11. 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...... of metabolic fluxes using metabolite balancing. This framework was employed to perform an in silico characterisation of the phenotypic behaviour of A. niger grown on different carbon sources. The effects on growth of single reaction deletions were assessed and essential biochemical reactions were identified...... for different carbon sources. Furthermore, application of the stoichiometric model for assessing the metabolic capabilities of A. niger to produce metabolites was evaluated by using succinate production as a case study....

  12. Unveiling Microbial Carbon Cycling Processes in Key U.S. Soils using ''Omics''

    Energy Technology Data Exchange (ETDEWEB)

    Myrold, David D. [Oregon State Univ., Corvallis, OR (United States); Bottomely, Peter J. [Oregon State Univ., Corvallis, OR (United States); Jumpponen, Ari [Kansas State Univ., Manhattan, KS (United States); Rice, Charles W. [Kansas State Univ., Manhattan, KS (United States); Zeglin, Lydia H. [Kansas State Univ., Manhattan, KS (United States); David, Maude M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Jansson, Janet K. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Prestat, Emmanuel [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Hettich, Robert L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2014-09-17

    biology approach, considering the complex soil microbial community as a functioning system and using state-of-the-art metatranscriptomic, metaproteomic, and metabolomic approaches. These omics tools were refined, applied to field experiments, and confirmed with controlled laboratory studies. Our experiments were designed to specifically identify microbial community members and processes that are instrumental players in processing of C in the prairie soils and how these processes are impacted by wetting and drying events. This project addresses a key ecosystem in the United States that current climate models predict will be subjected to dramatic changes in rainfall patterns as a result of global warming. Currently Mollisols, such as those of the tallgrass prairie, are thought to sequester more C than is released into the atmosphere, but it is not known what changes in rainfall patterns will have on future C fluxes. Through an analysis of the molecular response of the soil microbial community to shifts in precipitation cycles that are accompanied by phenologically driven changes in quality of plant C rhizodeposits, we gained deeper insight into how the metabolism of microbes has adapted to different precipitation regimes and the impact of this adaption on the fate of C deposited into soil. In doing so, we addressed key questions about the microbial cycling of C in soils that have been identified by the DOE.

  13. Games Uniforms Unveiled

    Institute of Scientific and Technical Information of China (English)

    Linda

    2008-01-01

    The uniforms for Beijing Olympics’ workers, technical staff and volunteers have been unveiled to mark the 200-day countdown to the Games. The uniforms feature the key element of the clouds of promise and will be in three colors:red for Beijing Olympic Games Committee staff, blue

  14. Phosphoketolase pathway contributes to carbon metabolism in cyanobacteria.

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    Xiong, Wei; Lee, Tai-Chi; Rommelfanger, Sarah; Gjersing, Erica; Cano, Melissa; Maness, Pin-Ching; Ghirardi, Maria; Yu, Jianping

    2015-12-07

    Central carbon metabolism in cyanobacteria comprises the Calvin-Benson-Bassham (CBB) cycle, glycolysis, the pentose phosphate (PP) pathway and the tricarboxylic acid (TCA) cycle. Redundancy in this complex metabolic network renders the rational engineering of cyanobacterial metabolism for the generation of biomass, biofuels and chemicals a challenge. Here we report the presence of a functional phosphoketolase pathway, which splits xylulose-5-phosphate (or fructose-6-phosphate) to acetate precursor acetyl phosphate, in an engineered strain of the model cyanobacterium Synechocystis (ΔglgC/xylAB), in which glycogen synthesis is blocked, and xylose catabolism enabled through the introduction of xylose isomerase and xylulokinase. We show that this mutant strain is able to metabolise xylose to acetate on nitrogen starvation. To see whether acetate production in the mutant is linked to the activity of phosphoketolase, we disrupted a putative phosphoketolase gene (slr0453) in the ΔglgC/xylAB strain, and monitored metabolic flux using (13)C labelling; acetate and 2-oxoglutarate production was reduced in the light. A metabolic flux analysis, based on isotopic data, suggests that the phosphoketolase pathway metabolises over 30% of the carbon consumed by ΔglgC/xylAB during photomixotrophic growth on xylose and CO2. Disruption of the putative phosphoketolase gene in wild-type Synechocystis also led to a deficiency in acetate production in the dark, indicative of a contribution of the phosphoketolase pathway to heterotrophic metabolism. We suggest that the phosphoketolase pathway, previously uncharacterized in photosynthetic organisms, confers flexibility in energy and carbon metabolism in cyanobacteria, and could be exploited to increase the efficiency of cyanobacterial carbon metabolism and photosynthetic productivity.

  15. Aerial and underwater carbon metabolism of a

    NARCIS (Netherlands)

    Clavier, J.; Chauvaud, L.; Carlier, A.; Amice, E.; van der Geest, M.; Labrosse, P.; Diagne, A.; Hily, H.

    2011-01-01

    Community respiration and primary production were measured in a dense intertidal Zostera noltii bed on the Banc d’Arguin, Mauritania (West Africa) under aerial and submerged conditions. Metabolism was studied in situ in dark and transparent benthic chambers. CO2 fluxes in the air were measured over

  16. Central carbon metabolism influences cellulase production in Bacillus licheniformis.

    Science.gov (United States)

    Wang, J; Liu, S; Li, Y; Wang, H; Xiao, S; Li, C; Liu, B

    2018-01-01

    Bacillus licheniformis that can produce cellulase including endo glucanase and glucosidase is an important industrial microbe for cellulose degradation. The purpose of this research was to assess the effect of endo glucanase gene bglC and glucosidase gene bglH on the central metabolic flux in B. licheniformis. bglC and bglH were knocked out using homologous recombination method, respectively, and the corresponding knockout strains were obtained for 13 C metabolic flux analysis. A significant change was observed in metabolic fluxes after 13 C metabolic flux ratio analysis. In both of the knockout strains, the increased fluxes of the pentose phosphate pathway and malic enzyme reaction enabled an elevated supply of NADPH which provided enough reducing power for the in vivo synthesis reactions. The fluxes through tricarboxylic acid cycle and anaplerotic reactions increased fast in the two knockout strains, which meant more energy generated. The changed fluxes in central carbon metabolism provided a holistic view of the physiological status in B. licheniformis and possible targets for further strain engineering. Cellulase is very important in the field of agriculture and bioenergy because of its degrading effect on cellulosic biomass. This study presented the effect of central carbon metabolism on cellulase production in Bacillus licheniformis. The study also provided a holistic view of the physiological status in B. licheniformis. The shifted metabolism provided a quantitative evaluation of the biosynthesis of cellulase and a priority ranked target list for further strain engineering. © 2017 The Society for Applied Microbiology.

  17. 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

  18. 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...

  19. Metabolic Dysfunction in Parkinson's Disease: Bioenergetics, Redox Homeostasis and Central Carbon Metabolism.

    Science.gov (United States)

    Anandhan, Annadurai; Jacome, Maria S; Lei, Shulei; Hernandez-Franco, Pablo; Pappa, Aglaia; Panayiotidis, Mihalis I; Powers, Robert; Franco, Rodrigo

    2017-07-01

    The loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc) and the accumulation of protein inclusions (Lewy bodies) are the pathological hallmarks of Parkinson's disease (PD). PD is triggered by genetic alterations, environmental/occupational exposures and aging. However, the exact molecular mechanisms linking these PD risk factors to neuronal dysfunction are still unclear. Alterations in redox homeostasis and bioenergetics (energy failure) are thought to be central components of neurodegeneration that contribute to the impairment of important homeostatic processes in dopaminergic cells such as protein quality control mechanisms, neurotransmitter release/metabolism, axonal transport of vesicles and cell survival. Importantly, both bioenergetics and redox homeostasis are coupled to neuro-glial central carbon metabolism. We and others have recently established a link between the alterations in central carbon metabolism induced by PD risk factors, redox homeostasis and bioenergetics and their contribution to the survival/death of dopaminergic cells. In this review, we focus on the link between metabolic dysfunction, energy failure and redox imbalance in PD, making an emphasis in the contribution of central carbon (glucose) metabolism. The evidence summarized here strongly supports the consideration of PD as a disorder of cell metabolism. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Carbon Metabolism in Lake Steinhuder Meer

    International Nuclear Information System (INIS)

    Ernst, D.

    1981-01-01

    Lake Steinhuder Meer is the largest lake in the Northern German plain. It is very shallow (average 1.35 m deep), highly productive and turbid due to a layer of loose sediments rich in organic matter (Ernst et al., 1980). It is an important recreational site, natural resort and still remarkable fishing area. It is fed by 2/3 from subsoil waters and by 1/3 by. rain. The response of the water body to increased nutrient load is investigated by enrichment experiments using plastic bags. Water in plastic bags is in contact with the atmosphere but is separated from the bottom sediment. Hence this technique may also give information about the roles of the sediment and the atmosphere in lake metabolism. Plasticisers may influence the experiment and mechanical damage may restrict the life-time of the facility. After several trials with polyethylene foils we now use a re-enforced PVC-foil. The material (Beneflex L) stands the wave movement for several weeks. Since Steinhuder Meer is not stratified we just pump the water into the bag. The water volume in the container is determined by a water clock

  1. The effects of phosphorus limitation on carbon metabolism in diatoms.

    Science.gov (United States)

    Brembu, Tore; Mühlroth, Alice; Alipanah, Leila; Bones, Atle M

    2017-09-05

    Phosphorus is an essential element for life, serving as an integral component of nucleic acids, lipids and a diverse range of other metabolites. Concentrations of bioavailable phosphorus are low in many aquatic environments. Microalgae, including diatoms, apply physiological and molecular strategies such as phosphorus scavenging or recycling as well as adjusting cell growth in order to adapt to limiting phosphorus concentrations. Such strategies also involve adjustments of the carbon metabolism. Here, we review the effect of phosphorus limitation on carbon metabolism in diatoms. Two transcriptome studies are analysed in detail, supplemented by other transcriptome, proteome and metabolite data, to gain an overview of different pathways and their responses. Phosphorus, nitrogen and silicon limitation responses are compared, and similarities and differences discussed. We use the current knowledge to propose a suggestive model for the carbon flow in phosphorus-replete and phosphorus-limited diatom cells.This article is part of the themed issue 'The peculiar carbon metabolism in diatoms'. © 2017 The Authors.

  2. Overview of the physiological ecology of carbon metabolism in seagrasses.

    Science.gov (United States)

    Touchette; Burkholder

    2000-07-30

    carbon sink to source. Unlike terrestrial plants, SPS apparently is not light-activated, and is positively influenced by increasing temperature and salinity. This response may indicate an osmotic adjustment in marine angiosperms, analogous to increased SPS activity as a cryoprotectant response in terrestrial non-halophytic plants. Sucrose synthase (SS, involved in sucrose metabolism and degradation in sink tissues) of both above- and belowground tissues decreases with tissue age. In belowground tissues, SS activity increases under low oxygen availability and with increasing temperatures, likely indicating increased metabolic carbohydrate demand. Respiration in seagrasses is primarily influenced by temperature and, in belowground tissues, by oxygen availability. Aboveground tissues (involved in C assimilation and other energy-costly processes) generally have higher respiration rates than belowground (mostly storage) tissues. Respiration rates increase with increasing temperature (in excess of 40 degrees C) and increasing water-column nitrate enrichment (Z. marina), which may help to supply the energy and carbon needed to assimilate and reduce nitrate. Seagrasses translocate oxygen from photosynthesizing leaves to belowground tissues for aerobic respiration. During darkness or extended periods of low light, belowground tissues can sustain extended anerobiosis. Documented alternate fermentation pathways have yielded high alanine, a metabolic 'strategy' that would depress production of the more toxic product ethanol, while conserving carbon skeletons and assimilated nitrogen. In comparison to the wealth of information available for terrestrial plants, little is known about the physiological ecology of seagrasses in carbon acquisition and metabolism. Many aspects of their carbon metabolism - controls by interactive environmental factors; and the role of carbon metabolism in salt tolerance, growth under resource-limited conditions, and survival through periods of dormancy

  3. Leishmania carbon metabolism in the macrophage phagolysosome- feast or famine?

    Science.gov (United States)

    McConville, Malcolm J; Saunders, Eleanor C; Kloehn, Joachim; Dagley, Michael J

    2015-01-01

    A number of medically important microbial pathogens target and proliferate within macrophages and other phagocytic cells in their mammalian hosts. While the majority of these pathogens replicate within the host cell cytosol or non-hydrolytic vacuolar compartments, a few, including protists belonging to the genus Leishmania, proliferate long-term within mature lysosome compartments.  How these parasites achieve this feat remains poorly defined. In this review, we highlight recent studies that suggest that Leishmania virulence is intimately linked to programmed changes in the growth rate and carbon metabolism of the obligate intra-macrophage stages. We propose that activation of a slow growth and a stringent metabolic response confers resistance to multiple stresses (oxidative, temperature, pH), as well as both nutrient limitation and nutrient excess within this niche. These studies highlight the importance of metabolic processes as key virulence determinants in Leishmania.

  4. Lord Shiva Statue Unveiled

    CERN Multimedia

    2004-01-01

    On 18 June, CERN unveiled an unusual new landmark, a 2m tall statue of the Indian deity Lord Shiva. The Director-General and Dr. Kakodkar watch as Mr.Chandrasekhar signs the Guest Book. The statue is a gift from India, celebrating CERN's long association with India which started in the 1960's and continues strongly today. It was unveiled by the Director General, Dr Robert Aymar, His Excellency Mr K. M. Chandrasekhar, Ambassador (WTO-Geneva) and Dr Anil Kakodkar, Chairman of the Atomic Energy Commission and Secretary, Dept of Atomic Energy, India. In the Hindu religion, this form of the dancing Lord Shiva is known as the Nataraj and symbolises Shakti, or life force. As a plaque alongside the statue explains, the belief is that Lord Shiva danced the Universe into existence, motivates it, and will eventually extinguish it. Carl Sagan drew the metaphor between the cosmic dance of the Nataraj and the modern study of the 'cosmic dance' of subatomic particles. The statue was made in India. The original sculpture was...

  5. Genetic response to metabolic fluctuations: correlation between central carbon metabolism and DNA replication in Escherichia coli

    Directory of Open Access Journals (Sweden)

    Szalewska-Pałasz Agnieszka

    2011-03-01

    Full Text Available Abstract Background Until now, the direct link between central carbon metabolism and DNA replication has been demonstrated only in Bacillus. subtilis. Therefore, we asked if this is a specific phenomenon, characteristic for this bacterium and perhaps for its close relatives, or a more general biological rule. Results We found that temperature-sensitivity of mutants in particular genes coding for replication proteins could be suppressed by deletions of certain genes coding for enzymes of the central carbon metabolism. Namely, the effects of dnaA46(ts mutation could be suppressed by dysfunction of pta or ackA, effects of dnaB(ts by dysfunction of pgi or pta, effects of dnaE486(ts by dysfunction of tktB, effects of dnaG(ts by dysfunction of gpmA, pta or ackA, and effects of dnaN159(ts by dysfunction of pta or ackA. The observed suppression effects were not caused by a decrease in bacterial growth rate. Conclusions The genetic correlation exists between central carbon metabolism and DNA replication in the model Gram-negative bacterium, E. coli. This link exists at the steps of initiation and elongation of DNA replication, indicating the important global correlation between metabolic status of the cell and the events leading to cell reproduction.

  6. Photosynthetic carbon metabolism in the submerged aquatic angiosperm Scirpus subterminalis

    Energy Technology Data Exchange (ETDEWEB)

    Beer, S; Wetzel, R G

    1981-01-01

    Scirpus subterminalis Torr., a submerged angiosperm abundant in many hardwater lakes of the Great Lakes region, was investigated for various photosynthetic carbon fixation properties in relation to available inorganic carbon and levels of carbon fixing enzymes. Photosynthetic experiments were CO/sub 2/ and HCO/sub 3//sup -/ were supplied at various concentrations showed that Scirpus was able to utilize HCO/sub 3//sup -/ at those concentrations close to natural conditions. However, when CO/sub 2/ concentrations were increased above ambient, photosynthetic rates increased markedly. It was concluded that the photosynthetic potential of this plant in many natural situations may be limited by inorganic carbon uptake in the light. Phosphoenolpyruvate carboxylase (PEPcase)/ribulose-1,5-bisphosphate carboxylase (ruBPcase) ratios of the leaves varied between 0.5 and 0.9 depending on substrate concentration during assay. The significance of PEP-mediated carbon fixation of Scirpus (basically a C/sub 3/ plant) in the dark was investigated. Malate accumulated in the leaves during the dark period of a 24-h cycle and malate levels decreased significantly during the following light period. The accumulation was not due to transport of malate from the roots. Carbon uptake rates in the dark by the leaves of Scirpus were lower than malate accumulation rates. Therefore, part of the malate was likely derived from respired CO/sub 2/. Carbon uptake rates in the light were much higher than malate turnover rates. It was estimated that carbon fixation via malate could contribute up to 12% to net photosynthetic rates. The ecological significance of this type of metabolism in submerged aquatics is discussed.

  7. 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.

  8. Integration of Carbon, Nitrogen, and Oxygen Metabolism in Escherichia coli

    Science.gov (United States)

    2012-10-22

    optimally, balancing effectively the conversion of carbon into energy versus biomass . To investigate the link between the metabolism of different nutrients...diverse nutrient conditions, E. coli  grows nearly optimally, balancing effectively the  conversion  of carbon  into energy versus  biomass . Here we  show... enzymatic  connections, with kinetic parameters taken from the  literature or computationally  inferred  based on  the data  from Aim 1. As proposed  initially

  9. Ecophysiology of terminal carbon metabolizing bacteria in anoxic sedimentary environments

    International Nuclear Information System (INIS)

    Phelps, T.J.

    1985-01-01

    Chemical, radiotracer, and microbiological experiments were used to understand the transformation of simple carbon compounds by anaerobic bacteria in diverse aquatic sediments and laboratory cultures. The mildly acidic sediments of Knack Lake (pH 6.2), displayed low rates of organic decomposition, and methane formation occurred almost exclusively from acetate. Low pH inhibited methanogenesis and organic decomposition. Fall turnover in Lake Mendota sediments was associated with dramatic changes in environmental parameters including: elevated concentrations of sulfate and carbon metabolites, increased rates of sulfate reduction, decreased levels of methanogenesis, increased ratio (by viable counts) of sulfate reducing to methanogenic bacteria, and higher 14 CO 2 / 14 C 4 + 14 CO 2 gas ratios produced during the biodegradation of 14 C-carbon substrates (e.g., acetate and methanol). Hydrogen consumption by sulfate reducers in Lake Mendota sediments and in co-cultures of Desulfovibrio vulgaris and Methanosarcina barkeri led to an alteration in the carbon and electron flow pathway resulting in increased CO 2 , sulfide production, and decreased methanogenesis. These data agreed with the environmental observations in Lake Mendota that high sulfate concentrations resulted in higher ratios of CO 2 /CH 4 produced from the degradation of organic matter. A new glycine-metabolizing acetogenic species was isolated and characterized from Knaack Lake which further extended the known diversity of anaerobic bacteria in nature

  10. Cyanobacterial carbon metabolism: Fluxome plasticity and oxygen dependence: Cyanobacterial Carbon Metabolism

    Energy Technology Data Exchange (ETDEWEB)

    Wan, Ni [Washington Univ., St. Louis, MO (United States); DeLorenzo, Drew M. [Washington Univ., St. Louis, MO (United States); He, Lian [Washington Univ., St. Louis, MO (United States); You, Le [Washington Univ., St. Louis, MO (United States); Immethun, Cheryl M. [Washington Univ., St. Louis, MO (United States); Wang, George [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Baidoo, Edward E. K. [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Hollinshead, Whitney [Washington Univ., St. Louis, MO (United States); Keasling, Jay D. [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States); Technical Univ. of Denmark, Lyngby (Denmark); Moon, Tae Seok [Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis Missouri 63130; Tang, Yinjie J. [Washington Univ., St. Louis, MO (United States)

    2017-03-30

    Synechocystis sp. strain PCC 6803 has been widely used as a photo-biorefinery chassis. Based on its genome annotation, this species contains a complete TCA cycle, an Embden-Meyerhof-Parnas pathway (EMPP), an oxidative pentose phosphate pathway (OPPP), and an Entner–Doudoroff pathway (EDP). To evaluate how Synechocystis 6803 catabolizes glucose under heterotrophic conditions, we performed 13C metabolic flux analysis, metabolite pool size analysis, gene knockouts, and heterologous expressions. The results revealed a cyclic mode of flux through the OPPP. Small, but non-zero, fluxes were observed through the TCA cycle and the malic shunt. Independent knockouts of 6-phosphogluconate dehydrogenase (gnd) and malic enzyme (me) corroborated these results, as neither mutant could grow under dark heterotrophic conditions. Our data also indicate that Synechocystis 6803 metabolism relies upon oxidative phosphorylation to generate ATP from NADPH under dark or insufficient light conditions. The pool sizes of intermediates in the TCA cycle, particularly acetyl-CoA, were found to be several fold lower in Synechocystis 6803 (compared to E. coli metabolite pool sizes), while its sugar phosphate intermediates were several-fold higher. Moreover, negligible flux was detected through the native, or heterologous, EDP in the wild type or Δgnd strains under heterotrophic conditions. Comparing photoautotrophic, photomixotrophic, and heterotrophic conditions, the Calvin cycle, OPPP, and EMPP in Synechocystis 6803 possess the ability to regulate their fluxes under various growth conditions (plastic), whereas its TCA cycle always maintains at low levels (rigid). This work also demonstrates how genetic profiles do not always reflect actual metabolic flux through native or heterologous pathways. Biotechnol. Bioeng. 2017;114: 1593–1602. © 2017 Wiley Periodicals, Inc.

  11. 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.

  12. Seagrass metabolism and carbon dynamics in a tropical coastal embayment.

    Science.gov (United States)

    Ganguly, Dipnarayan; Singh, Gurmeet; Ramachandran, Purvaja; Selvam, Arumughan Paneer; Banerjee, Kakolee; Ramachandran, Ramesh

    2017-10-01

    Net ecosystem metabolism and subsequent changes in environmental variables were studied seasonally in the seagrass-dominated Palk Bay, located along the southeast coast of India. The results showed that although the water column was typically net heterotrophic, the ecosystem as a whole displayed autotrophic characteristics. The mean net community production from the seagrass meadows was 99.31 ± 45.13 mM C m -2  d -1 , while the P/R ratio varied between 1.49 and 1.56. Oxygen produced through in situ photosynthesis, exhibited higher dependence over dissolved CO 2 and available light. Apportionment of carbon stores in biomass indicated that nearly three-fourths were available belowground compared to aboveground. However, the sediment horizon accumulated nearly 40 times more carbon than live biomass. The carbon storage capacities of the sediments and seagrass biomass were comparable with the global mean for seagrass meadows. The results of this study highlight the major role of seagrass meadows in modification of seawater chemistry. Though the seagrass meadows of Palk Bay are increasingly subject to human impacts, with coupled regulatory and management efforts focused on improved water quality and habitat conservation, these key coastal ecosystems will continue to be valuable for climate change mitigation, considering their vital role in C dynamics and interactions with the overlying water column.

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

    Directory of Open Access Journals (Sweden)

    Joshua M. Corbin

    2016-07-01

    Full Text Available 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.

  14. 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

  15. Organic carbon balance and net ecosystem metabolism in Chesapeake Bay

    Science.gov (United States)

    Kemp, W.M.; Smith, E.M.; Marvin-DiPasquale, M.; Boynton, W.R.

    1997-01-01

    The major fluxes of organic carbon associated with physical transport and biological metabolism were compiled, analyzed and compared for the mainstem portion of Chesapeake Bay (USA). In addition, 5 independent methods were used to calculate the annual mean net ecosystem metabolism (NEM = production - respiration) for the integrated Bay. These methods, which employed biogeochemical models, nutrient mass-balances anti summation of individual organic carbon fluxes, yielded remarkably similar estimates, with a mean NEM of +50 g C m-2 yr-1 (?? SE = 751, which is approximately 8% of the estimated annual average gross primary production. These calculations suggest a strong cross-sectional pattern in NEM throughout the Bay, wherein net heterotrophic metabolism prevails in the pelagic zones of the main channel, while net autotrophy occurs in the littoral zones which flank the deeper central area. For computational purposes, the estuary was separated into 3 regions along the land-sea gradient: (1) the oligohaline Upper Bay (11% of total area); (2) the mesohaline Mid Bay (36% of area); and (3) the polyhaline Lower Bay (53% of area). A distinct regional trend in NEM was observed along this salinity gradient, with net here(atrophy (NEM = 87 g C m-2 yr-1) in the Upper Bay, balanced metabolism in the Mid Bay and net autotrophy (NEM = +92 g C m-2 yr-1) in the Lower Bay. As a consequence of overall net autotrophy, the ratio of dissolved inorganic nitrogen (DIN) to total organic nitrogen (TON) changed from DIN:TON = 5.1 for riverine inputs to DIN:TON = 0.04 for water exported to the ocean. A striking feature of this organic C mass-balance was the relative dominance of biologically mediated metabolic fluxes compared to physical transport fluxes. The overall ratio of physical TOC inputs (1) to biotic primary production (P) was 0.08 for the whole estuary, but varied dramatically from 2.3 in the Upper Bay to 0.03 in the Mid and Lower Bay regions. Similarly, ecosystem respiration was

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

    DEFF Research Database (Denmark)

    Jensen, Peter Ruhdal; Michelsen, Ole

    1992-01-01

    strain is not able to utilize the resulting proton motive force for ATP synthesis. Indeed, the ratio of ATP concentration to ADP concentration was decreased from 19 in the wild type to 7 in the atp mutant, and the membrane potential of the atp deletion strain was increased by 20%, confirming......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...... rate and growth yield were decreased less than expected for a shift from oxidative phosphorylation to glycolysis alone as a source of ATP. Moreover, the respiration rate of a atp deletion strain was increased by 40% compared with the wild-type strain. This result is surprising, since the atp deletion...

  17. The metabolism and dosimetry of carbon-14 labelled compounds

    International Nuclear Information System (INIS)

    Crawley, F.E.H.

    1977-01-01

    The number of compounds labelled at high specific activity with carbon-14 has greatly increased over the last few years. There are limited biological data available to enable an assessment of the internal radiation dose and to identify the critical tissues after an intake of such compounds. The ICRP consider two Model Systems for deriving dose. Both Models assume a total elimination of the carbon-14 in the breath and only bone or whole body as critical tissues and are not representative of the majority of the compounds now available. A research programme has been established to study the rate of excretion and tissue distribution of selected carbon-14 labelled compounds in the rat after intravenous injection, pulmonary and gastric intubation and skin absorption. These metabolic data have been used to calculate the committed dose equivalent and maximum permissible annual intake (MPAI) for various tissues in man on the assumption that the experimental data obtained in the rat are true for man. To date potassium 14 C-cyanide and 14 C-methanol have been studied. The values for the MPAI's derived from the doses to individual tissues are more restrictive than values calculated from the whole body doses. The MPAI calculated from excretion data in terms of whole body dose is 31 mCi for 14 C-cyanide and 25 mCi for 14 C-methanol. However, the critical tissue for 14 C-cyanide is the stomach with an MPAI of 1.5 mCi based on a dose of 10.7 rem mCi -1 . This was an order of magnitude greater than the dose to any other region of the GI tract and 5 times that to the testis. The critical organs for 14 C-methanol are the testis (MPAI 2.5 mCi) for males and the ovaries (MPAI 6.2 mCi) for females

  18. An Integrative Approach to Energy Carbon and Redox Metabolism In Cyanobacterium Synechocystis

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Ross Overbeek

    2003-06-30

    The main objectives for the first year were to produce a detailed metabolic reconstruction of synechocystis sp.pcc6803 especially in interrelated arrears of photosynthesis respiration and central carbon metabolism to support a more complete understanding and modeling of this organism. Additionally, IG, 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.

  19. Nutrients in Energy and One-Carbon Metabolism: Learning from Metformin Users

    Directory of Open Access Journals (Sweden)

    Fedra Luciano-Mateo

    2017-02-01

    Full Text Available Metabolic vulnerability is associated with age-related diseases and concomitant co-morbidities, which include obesity, diabetes, atherosclerosis and cancer. Most of the health problems we face today come from excessive intake of nutrients and drugs mimicking dietary effects and dietary restriction are the most successful manipulations targeting age-related pathways. Phenotypic heterogeneity and individual response to metabolic stressors are closely related food intake. Understanding the complexity of the relationship between dietary provision and metabolic consequences in the long term might provide clinical strategies to improve healthspan. New aspects of metformin activity provide a link to many of the overlapping factors, especially the way in which organismal bioenergetics remodel one-carbon metabolism. Metformin not only inhibits mitochondrial complex 1, modulating the metabolic response to nutrient intake, but also alters one-carbon metabolic pathways. Here, we discuss findings on the mechanism(s of action of metformin with the potential for therapeutic interpretations.

  20. 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

    This study focused on how phosphorus and carbon control pelagic bacteria in lakes over a gradient of dissolved organic carbon (DOC from 6.7 to 29.5 mg C L(-1)) and phosphorus (P-tot from 5 to 19 mu g L(-1)). Five oligotrophic lakes in southern Sweden were sampled in late autumn. Phosphate...... carbon mineralization in this kind of system during autumn is conditioned by the combined availability of labile carbon and phosphorus, with the assimilated carbon mainly transformed to inorganic carbon in respiration, contributing to CO(2) supersaturation in these systems....

  1. 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.

  2. Chemical Constraints Governing the Origin of Metabolism: The Thermodynamic Landscape of Carbon Group Transformations

    Science.gov (United States)

    Weber, Arthur L.; Fonda, Mark (Technical Monitor)

    2001-01-01

    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 were estimated for four types 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 that (1) when carbon-carbon bond cleavage involves two different types of functional groups, 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) the energy of carbon-carbon bond transformation is strongly dependent on the type of functional group that donates the shared electron-pair during cleavage, and the group that accepts the shared electron-pair during synthesis, and (3) the energetics of C-C bond transformation is determined primarily by the half-reaction energies of the couples: carbonyl/carboxylic acid, carboxylic acid/carbon dioxide, alcohol/carbonyl, and hydrocarbon/alcohol. The energy of hydrogen-transfer between carbon groups was found to depend on the functional group class of both the hydrogen-donor and hydrogen-acceptor. From these and other observations we concluded that the chemistry of the origin of metabolism (and to a lesser degree modem metabolism) is strongly constrained by the (1) limited disproportionation energy of organic substrates that can be dissipated in a few irreversible reactions, (2) the energy-dominance of few half-reaction couples in carbon-carbon bond transformation that establishes whether a chemical reaction is energetically irreversible, reversible or unfeasible, and (3) the dependence of the transformation-energy on the oxidation state of carbon groups (functional group type) which is

  3. Proteins involved in flor yeast carbon metabolism under biofilm formation conditions.

    Science.gov (United States)

    Moreno-García, Jaime; García-Martínez, Teresa; Moreno, Juan; Mauricio, Juan Carlos

    2015-04-01

    A lack of sugars during the production of biologically aged wines after fermentation of grape must causes flor yeasts to metabolize other carbon molecules formed during fermentation (ethanol and glycerol, mainly). In this work, a proteome analysis involving OFFGEL fractionation prior to LC/MS detection was used to elucidate the carbon metabolism of a flor yeast strain under biofilm formation conditions (BFC). The results were compared with those obtained under non-biofilm formation conditions (NBFC). Proteins associated to processes such as non-fermentable carbon uptake, the glyoxylate and TCA cycles, cellular respiration and inositol metabolism were detected at higher concentrations under BFC than under the reference conditions (NBFC). This study constitutes the first attempt at identifying the flor yeast proteins responsible for the peculiar sensory profile of biologically aged wines. A better metabolic knowledge of flor yeasts might facilitate the development of effective strategies for improved production of these special wines. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Lipids Reprogram Metabolism to Become a Major Carbon Source for Histone Acetylation

    DEFF Research Database (Denmark)

    McDonnell, Eoin; Crown, Scott B; Fox, Douglas B

    2016-01-01

    Cells integrate nutrient sensing and metabolism to coordinate proper cellular responses to a particular nutrient source. For example, glucose drives a gene expression program characterized by activating genes involved in its metabolism, in part by increasing glucose-derived histone acetylation....... Here, we find that lipid-derived acetyl-CoA is a major source of carbon for histone acetylation. Using (13)C-carbon tracing combined with acetyl-proteomics, we show that up to 90% of acetylation on certain histone lysines can be derived from fatty acid carbon, even in the presence of excess glucose...

  5. Metabolic fluxes in the central carbon metabolism of Dinoroseobacter shibae and Phaeobacter gallaeciensis, two members of the marine Roseobacter clade

    Directory of Open Access Journals (Sweden)

    Rabus Ralf

    2009-09-01

    Full Text Available Abstract Background In the present work the central carbon metabolism of Dinoroseobacter shibae and Phaeobacter gallaeciensis was studied at the level of metabolic fluxes. These two strains belong to the marine Roseobacter clade, a dominant bacterial group in various marine habitats, and represent surface-associated, biofilm-forming growth (P. gallaeciensis and symbiotic growth with eukaryotic algae (D. shibae. Based on information from recently sequenced genomes, a rich repertoire of pathways has been identified in the carbon core metabolism of these organisms, but little is known about the actual contribution of the various reactions in vivo. Results Using 13C labelling techniques in specifically designed experiments, it could be shown that glucose-grown cells of D. shibae catabolise the carbon source exclusively via the Entner-Doudoroff pathway, whereas alternative routes of glycolysis and the pentose phosphate pathway are obviously utilised for anabolic purposes only. Enzyme assays confirmed this flux pattern and link the lack of glycolytic flux to the absence of phosphofructokinase activity. The previously suggested formation of phosphoenolpyruvate from pyruvate during mixotrophic CO2 assimilation was found to be inactive under the conditions studied. Moreover, it could be shown that pyruvate carboxylase is involved in CO2 assimilation and that the cyclic respiratory mode of the TCA cycle is utilised. Interestingly, the use of intracellular pathways was highly similar for P. gallaeciensis. Conclusion The present study reveals the first insight into pathway utilisation within the Roseobacter group. Fluxes through major intracellular pathways of the central carbon metabolism, which are closely linked to the various important traits found for the Roseobacter clade, could be determined. The close similarity of fluxes between the two physiologically rather different species might provide the first indication of more general key properties among

  6. Carbon balance studies of glucose metabolism in rat cerebral cortical synaptosomes

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, U; Brand, K

    1982-07-01

    Synaptosomes were isolated from rat cerebral cortex and incubated with (U-/sup 14/C)-, (1-/sup 14/C)- or (6-/sup 14/C)glucose. Glucose utilization and the metabolic partitioning of glucose carbon in products were determined by isotopic methods. From the data obtained a carbon balance was constructed, showing lactate to be the main product of glucose metabolism, followed by CO/sup 2/, amino acids and pyruvate. Measuring the release of /sup 14/CO/sup 2/ from glucose labelled in three different positions allowed the construction of a flow diagram of glucose carbon atoms in synaptosomes, which provides information about the contribution of the various pathways of glucose metabolism. Some 2% of glucose utilized was calculated to be degraded via the pentose phosphate pathway. Addition of chlorpromazine, imipramine or haloperidol at concentrations of 10(-5) M reduced glucose utilisation by 30% without changing the distribution pattern of radioactivity in the various products.

  7. 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...... temperature regimes. AM symbiosis modulated C metabolic enzymes, thereby inducing an accumulation of soluble sugars, which may have contributed to an increased tolerance to low temperature, and therefore higher Pn in maize plants....

  8. Reconstruction of the central carbon metabolism of Aspergillus niger

    DEFF Research Database (Denmark)

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

    2003-01-01

    database for annotation of genes identified in future genome sequencing projects on aspergilli. Based on the metabolic reconstruction, a stoichiometric model was set up that includes 284 metabolites and 335 reactions, of which 268 represent biochemical conversions and 67 represent transport processes...

  9. Altered carbon dioxide metabolism and creatine abnormalities in rett syndrome

    NARCIS (Netherlands)

    Halbach, Nicky S J; Smeets, Eric E J; Bierau, Jörgen; Keularts, Irene M L W; Plasqui, Guy; Julu, Peter O O; Engerström, Ingegerd Witt; Bakker, Jaap A.; Curfs, Leopold M G

    2012-01-01

    Despite their good appetite, many females with Rett syndrome (RTT) meet the criteria for moderate to severe malnutrition. Although feeding difficulties may play a part in this, other constitutional factors such as altered metabolic processes are suspected. Irregular breathing is a common clinical

  10. 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

  11. Postillumination burst of carbon dioxide in crassalacean Acid metabolism plants.

    Science.gov (United States)

    Crews, C E; Vines, H M; Black, C C

    1975-04-01

    Immediately following exposure to light, a postillumination burst of CO(2) has been detected in Crassulacean acid metabolism plants. A detailed study with pineapple (Ananas comosus) leaves indicates that the postillumination burst changes its amplitude and kinetics during the course of a day. In air, the postillumination burst in pineapple leaves generally is exhibited as two peaks. The postillumination burst is sensitive to atmospheric CO(2) and O(2) concentrations as well as to the light intensity under which plants are grown. We propose that the CO(2) released in the first postillumination burst peak is indicative of photorespiration since it is sensitive to either O(2) or CO(2) concentration while the second CO(2) evolution peak is likely due to decarboxylation of organic acids involved in Crassulacean acid metabolism.In marked contrast to other higher plants, the postillumination burst in Crassulacean acid metabolism plants can be equal to or greater than the rate of photosynthesis. Photosynthesis in pineapple leaves also varies throughout a day. Both photosynthesis and the postillumination burst have a daily variation which apparently is a complex function of degree of leaf acidity, growth light intensity, ambient gas phase, and the time a plant has been exposed to a given gas.

  12. Genetic signatures in choline and 1-carbon metabolism are associated with the severity of hepatic steatosis

    Science.gov (United States)

    Corbin, Karen D.; Abdelmalek, Manal F.; Spencer, Melanie D.; da Costa, Kerry-Ann; Galanko, Joseph A.; Sha, Wei; Suzuki, Ayako; Guy, Cynthia D.; Cardona, Diana M.; Torquati, Alfonso; Diehl, Anna Mae; Zeisel, Steven H.

    2013-01-01

    Choline metabolism is important for very low-density lipoprotein secretion, making this nutritional pathway an important contributor to hepatic lipid balance. The purpose of this study was to assess whether the cumulative effects of multiple single nucleotide polymorphisms (SNPs) across genes of choline/1-carbon metabolism and functionally related pathways increase susceptibility to developing hepatic steatosis. In biopsy-characterized cases of nonalcoholic fatty liver disease and controls, we assessed 260 SNPs across 21 genes in choline/1-carbon metabolism. When SNPs were examined individually, using logistic regression, we only identified a single SNP (PNPLA3 rs738409) that was significantly associated with severity of hepatic steatosis after adjusting for confounders and multiple comparisons (P=0.02). However, when groupings of SNPs in similar metabolic pathways were defined using unsupervised hierarchical clustering, we identified groups of subjects with shared SNP signatures that were significantly correlated with steatosis burden (P=0.0002). The lowest and highest steatosis clusters could also be differentiated by ethnicity. However, unique SNP patterns defined steatosis burden irrespective of ethnicity. Our results suggest that analysis of SNP patterns in genes of choline/1-carbon metabolism may be useful for prediction of severity of steatosis in specific subsets of people, and the metabolic inefficiencies caused by these SNPs should be examined further.—Corbin, K. D., Abdelmalek, M. F., Spencer, M. D., da Costa, K.-A., Galanko, J. A., Sha, W., Suzuki, A., Guy, C. D., Cardona, D. M., Torquati, A., Diehl, A. M., Zeisel, S. H. Genetic signatures in choline and 1-carbon metabolism are associated with the severity of hepatic steatosis. PMID:23292069

  13. Characterization and Modeling Of Microbial Carbon Metabolism In Thawing Permafrost

    Science.gov (United States)

    Graham, D. E.; Phelps, T. J.; Xu, X.; Carroll, S.; Jagadamma, S.; Shakya, M.; Thornton, P. E.; Elias, D. A.

    2012-12-01

    Increased annual temperatures in the Arctic are warming the surface and subsurface, resulting in thawing permafrost. Thawing exposes large pools of buried organic carbon to microbial degradation, increasing greenhouse gas generation and emission. Most global-scale land-surface models lack depth-dependent representations of carbon conversion and GHG transport; therefore they do not adequately describe permafrost thawing or microbial mineralization processes. The current work was performed to determine how permafrost thawing at moderately elevated temperatures and anoxic conditions would affect CO2 and CH4 generation, while parameterizing depth-dependent GHG production processes with respect to temperature and pH in biogeochemical models. These enhancements will improve the accuracy of GHG emission predictions and identify key biochemical and geochemical processes for further refinement. Three core samples were obtained from discontinuous permafrost terrain in Fairbanks, AK with a mean annual temperature of -3.3 °C. Each core was sectioned into surface/near surface (0-0.8 m), active layer (0.8-1.6 m), and permafrost (1.6-2.2 m) horizons, which were homogenized for physico-chemical characterization and microcosm construction. Surface samples had low pH values (6.0), low water content (18% by weight), low organic carbon (0.8%), and high C:N ratio (43). Active layer samples had higher pH values (6.4), higher water content (34%), more organic carbon (1.4%) and a lower C:N ratio (24). Permafrost samples had the highest pH (6.5), highest water content (46%), high organic carbon (2.5%) and the lowest C:N ratio (19). Most organic carbon was quantified as labile or intermediate pool versus stable pool in each sample, and all samples had low amounts of carbonate. Surface layer microcosms, containing 20 g sediment in septum-sealed vials, were incubated under oxic conditions, while similar active and permafrost layer samples were anoxic. These microcosms were incubated at -2

  14. 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).

  15. Systems assessment of transcriptional regulation on central carbon metabolism by Cra and CRP.

    Science.gov (United States)

    Kim, Donghyuk; Seo, Sang Woo; Gao, Ye; Nam, Hojung; Guzman, Gabriela I; Cho, Byung-Kwan; Palsson, Bernhard O

    2018-04-06

    Two major transcriptional regulators of carbon metabolism in bacteria are Cra and CRP. CRP is considered to be the main mediator of catabolite repression. Unlike for CRP, in vivo DNA binding information of Cra is scarce. Here we generate and integrate ChIP-exo and RNA-seq data to identify 39 binding sites for Cra and 97 regulon genes that are regulated by Cra in Escherichia coli. An integrated metabolic-regulatory network was formed by including experimentally-derived regulatory information and a genome-scale metabolic network reconstruction. Applying analysis methods of systems biology to this integrated network showed that Cra enables optimal bacterial growth on poor carbon sources by redirecting and repressing glycolysis flux, by activating the glyoxylate shunt pathway, and by activating the respiratory pathway. In these regulatory mechanisms, the overriding regulatory activity of Cra over CRP is fundamental. Thus, elucidation of interacting transcriptional regulation of core carbon metabolism in bacteria by two key transcription factors was possible by combining genome-wide experimental measurement and simulation with a genome-scale metabolic model.

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

    NARCIS (Netherlands)

    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,

  17. Metabolism and risks from tritium and carbon-14 in the developing organism

    International Nuclear Information System (INIS)

    Gerber, G.B.; Kirchmann, R.; Hoek, J. van den

    1987-01-01

    In this review the risks are considered from tritium and carbon-14 to the developing organs of mammals. It mainly deals with H-3 but the conclusions are largely valid also for C-14. The metabolism and average tissue of THO as well as of organically bound tritium are discussed. Dosimetry of radiosensitive structures is also considered. 14 refs.; 2 figs.; 1 table

  18. Determinants of maternal pregnancy one-carbon metabolism and newborn human DNA methylation profiles

    NARCIS (Netherlands)

    N.H. van Mil (Nina); M.I. Bouwl-Both (Marieke I.); L. Stolk (Lisette); M.M.P.J. Verbiest (Michael); A. Hofman (Albert); V.W.V. Jaddoe (Vincent); F.C. Verhulst (Frank); P.H.C. Eilers (Paul); A.G. Uitterlinden (André); E.A.P. Steegers (Eric); H.W. Tiemeier (Henning); R.P.M. Steegers-Theunissen (Régine)

    2014-01-01

    textabstractMaternal one-carbon (1-C) metabolism provides methylgroups for fetal development and programing by DNA methylation as one of the underlying epigenetic mechanisms. We aimed to investigate maternal 1-C biomarkers, folic acid supplement use, and MTHFR C677T genotype as determinants of 1-C

  19. 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

  20. 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

  1. Cyanobacterial carbon metabolism: Fluxome plasticity and oxygen dependence

    DEFF Research Database (Denmark)

    Wan, Ni; Delorenzo, Drew M.; He, Lian

    2017-01-01

    Synechocystis sp. strain PCC 6803 has been widely used as a photo-biorefinery chassis. Based on its genome annotation, this species contains a complete TCA cycle, an Embden-Meyerhof-Parnas pathway (EMPP), an oxidative pentose phosphate pathway (OPPP), and an Entner-Doudoroff pathway (EDP). To eva...... the ability to regulate their fluxes under various growth conditions (plastic), whereas its TCA cycle always maintains at low levels (rigid). This work also demonstrates how genetic profiles do not always reflect actual metabolic flux through native or heterologous pathways....

  2. France: the programme of festivities is unveiled

    CERN Multimedia

    2004-01-01

    The programme of events to be held in the local French area in honour of CERN's fiftieth anniversary was unveiled in the CMS hall on 26 April at a ceremony attended by many local authority representatives.

  3. Folic acid, one-carbon metabolism & childhood cancer

    Directory of Open Access Journals (Sweden)

    Nirmalya Roy Moulik

    2017-01-01

    Full Text Available Folate has been studied in relation to many diseases, especially cancer. Although it has been postulated to exert a dual effect on development of cancer, its role remains to be clearly defined. Its effect on cancer is the result of gene-nutrient interaction between the genes in folate metabolic pathway and dietary folate availability; mutations in genes of folate metabolism have been shown to alter individual susceptibility to certain childhood cancers as well as response to cancer chemotherapy. Although mandatory fortification of food items with folate has been initiated in some countries, many countries are yet to adopt this due to concerns about undesired adverse effects of high folate levels on health, especially cancer. However, initial reports suggest that folate fortification has led to reduction in incidence of certain childhood cancers such as neuroblastoma, wilms tumour and leukaemias. Despite studies showing folate depletion during antifolate chemotherapy and higher toxicity of chemotherapy in folate-depleted individuals, folate supplementation during cancer chemotherapy is not routinely recommended. Studies investigating the precise effect of folate supplementation during chemotherapy on both short- and long-term outcomes of cancer are needed to arrive at a consensus guideline.

  4. Georges Charpak street sign unveiled

    CERN Multimedia

    Paola Catapano

    2011-01-01

    While it might not be the only French street named in honour of the late Georges Charpak, who passed away in September 2010 at the age of 87, the street chosen by the mayor of Saint-Genis-Pouilly is certainly the only one located directly opposite the CERN "campus". The road overlooks buildings on the CERN Meyrin site, where Georges Charpak spent most of his career as a physicist, conducting the research that won him the Nobel Prize in Physics in 1992.   From left to right: Sigurd Lettow, Dominique Charpak and the mayor of Saint-Genis-Pouilly. The unveiling took place on 17 October and was organised by the mayor of Saint-Genis-Pouilly. George Charpak’s wife, Dominique, and Sigurd Lettow, CERN Director of Administration and General Infrastructure, attended what was an intimate and touching ceremony. The mayor’s speech at the event praised Georges’ commitment to scientific education. The highlight of the event, however, was a witty and humorous ...

  5. Net Community Metabolism and Seawater Carbonate Chemistry Scale Non-intuitively with Coral Cover

    Directory of Open Access Journals (Sweden)

    Heather N. Page

    2017-05-01

    Full Text Available Coral cover and reef health have been declining globally as reefs face local and global stressors including higher temperature and ocean acidification (OA. Ocean warming and acidification will alter rates of benthic reef metabolism (i.e., primary production, respiration, calcification, and CaCO3 dissolution, but our understanding of community and ecosystem level responses is limited in terms of functional, spatial, and temporal scales. Furthermore, dramatic changes in coral cover and benthic metabolism could alter seawater carbonate chemistry on coral reefs, locally alleviating or exacerbating OA. This study examines how benthic metabolic rates scale with changing coral cover (0–100%, and the subsequent influence of these coral communities on seawater carbonate chemistry based on mesocosm experiments in Bermuda and Hawaii. In Bermuda, no significant differences in benthic metabolism or seawater carbonate chemistry were observed for low (40% and high (80% coral cover due to large variability within treatments. In contrast, significant differences were detected between treatments in Hawaii with benthic metabolic rates increasing with increasing coral cover. Observed increases in daily net community calcification and nighttime net respiration scaled proportionally with coral cover. This was not true for daytime net community organic carbon production rates, which increased the most between 0 and 20% coral cover and then less so between 20 and 100%. Consequently, diel variability in seawater carbonate chemistry increased with increasing coral cover, but absolute values of pH, Ωa, and pCO2 were not significantly different during daytime. To place the results of the mesocosm experiments into a broader context, in situ seawater carbon dioxide (CO2 at three reef sites in Bermuda and Hawaii were also evaluated; reefs with higher coral cover experienced a greater range of diel CO2 levels, complementing the mesocosm results. The results from this study

  6. Robust metabolic responses to varied carbon sources in natural and laboratory strains of Saccharomyces cerevisiae.

    Directory of Open Access Journals (Sweden)

    Wayne A Van Voorhies

    Full Text Available Understanding factors that regulate the metabolism and growth of an organism is of fundamental biologic interest. This study compared the influence of two different carbon substrates, dextrose and galactose, on the metabolic and growth rates of the yeast Saccharomyces cerevisiae. Yeast metabolic and growth rates varied widely depending on the metabolic substrate supplied. The metabolic and growth rates of a yeast strain maintained under long-term laboratory conditions was compared to strain isolated from natural condition when grown on different substrates. Previous studies had determined that there are numerous genetic differences between these two strains. However, the overall metabolic and growth rates of a wild isolate of yeast was very similar to that of a strain that had been maintained under laboratory conditions for many decades. This indicates that, at in least this case, metabolism and growth appear to be well buffered against genetic differences. Metabolic rate and cell number did not co-vary in a simple linear manner. When grown in either dextrose or galactose, both strains showed a growth pattern in which the number of cells continued to increase well after the metabolic rate began a sharp decline. Previous studied have reported that O₂ consumption in S. cerevisiae grown in reduced dextrose levels were elevated compared to higher levels. Low dextrose levels have been proposed to induce caloric restriction and increase life span in yeast. However, there was no evidence that reduced levels of dextrose increased metabolic rates, measured by either O₂ consumption or CO₂ production, in the strains used in this study.

  7. Novel Members of the Cra Regulon Involved in Carbon Metabolism in Escherichia coli▿ †

    Science.gov (United States)

    Shimada, Tomohiro; Yamamoto, Kaneyoshi; Ishihama, Akira

    2011-01-01

    Cra (catabolite repressor activator) is a global regulator of the genes for carbon metabolism in Escherichia coli. To gain insights into the regulatory roles of Cra, attempts were made to identify the whole set of regulation targets using an improved genomic SELEX (systematic evolution of ligands by exponential enrichment) system. Surprisingly, a total of 164 binding sites were identified for Cra, 144 (88%) of which were newly identified. The majority of known targets were included in the SELEX chip pattern. The promoters examined by the lacZ reporter assay in vivo were all regulated by Cra. These two lines of evidence indicate that a total of as many as 178 promoters are under the control of Cra. The majority of Cra targets are the genes coding for the enzymes involved in central carbon metabolism, covering all the genes for the enzymes involved in glycolysis and metabolism downstream of glycolysis, including the tricarboxylic acid (TCA) cycle and aerobic respiration. Taken together, we propose that Cra plays a key role in balancing the levels of the enzymes for carbon metabolism. PMID:21115656

  8. Novel members of the Cra regulon involved in carbon metabolism in Escherichia coli.

    Science.gov (United States)

    Shimada, Tomohiro; Yamamoto, Kaneyoshi; Ishihama, Akira

    2011-02-01

    Cra (catabolite repressor activator) is a global regulator of the genes for carbon metabolism in Escherichia coli. To gain insights into the regulatory roles of Cra, attempts were made to identify the whole set of regulation targets using an improved genomic SELEX (systematic evolution of ligands by exponential enrichment) system. Surprisingly, a total of 164 binding sites were identified for Cra, 144 (88%) of which were newly identified. The majority of known targets were included in the SELEX chip pattern. The promoters examined by the lacZ reporter assay in vivo were all regulated by Cra. These two lines of evidence indicate that a total of as many as 178 promoters are under the control of Cra. The majority of Cra targets are the genes coding for the enzymes involved in central carbon metabolism, covering all the genes for the enzymes involved in glycolysis and metabolism downstream of glycolysis, including the tricarboxylic acid (TCA) cycle and aerobic respiration. Taken together, we propose that Cra plays a key role in balancing the levels of the enzymes for carbon metabolism.

  9. Effect of Carbon Monoxide on Active Oxygen Metabolism of Postharvest Jujube

    OpenAIRE

    Shaoying Zhang; Qin Li; Yulan Mao

    2014-01-01

    To prolong the shelf life postharvest jujube, the effect of carbon monoxide (CO) on senescence of postharvest jujube in relation to active oxygen metabolism was investigated. Jujubes were fumigated with CO gas at 5, 10, 20 or 40μmol/L for 1 h, and then stored for 30 days at room temperature. Changes in membrane permeability, malonaldehyde (MDA), H2O2, O2•− content, and activities of active oxygen metabolism associated enzymes including superoxide dismutase (SOD), catalase (CAT) and peroxidase...

  10. A Natural Light/Dark Cycle Regulation of Carbon-Nitrogen Metabolism and Gene Expression in Rice Shoots.

    Science.gov (United States)

    Li, Haixing; Liang, Zhijun; Ding, Guangda; Shi, Lei; Xu, Fangsen; Cai, Hongmei

    2016-01-01

    Light and temperature are two particularly important environmental cues for plant survival. Carbon and nitrogen are two essential macronutrients required for plant growth and development, and cellular carbon and nitrogen metabolism must be tightly coordinated. In order to understand how the natural light/dark cycle regulates carbon and nitrogen metabolism in rice plants, we analyzed the photosynthesis, key carbon-nitrogen metabolites, and enzyme activities, and differentially expressed genes and miRNAs involved in the carbon and nitrogen metabolic pathway in rice shoots at the following times: 2:00, 6:00, 10:00, 14:00, 18:00, and 22:00. Our results indicated that more CO2 was fixed into carbohydrates by a high net photosynthetic rate, respiratory rate, and stomatal conductance in the daytime. Although high levels of the nitrate reductase activity, free ammonium and carbohydrates were exhibited in the daytime, the protein synthesis was not significantly facilitated by the light and temperature. In mRNA sequencing, the carbon and nitrogen metabolism-related differentially expressed genes were obtained, which could be divided into eight groups: photosynthesis, TCA cycle, sugar transport, sugar metabolism, nitrogen transport, nitrogen reduction, amino acid metabolism, and nitrogen regulation. Additionally, a total of 78,306 alternative splicing events have been identified, which primarily belong to alternative 5' donor sites, alternative 3' acceptor sites, intron retention, and exon skipping. In sRNA sequencing, four carbon and nitrogen metabolism-related miRNAs (osa-miR1440b, osa-miR2876-5p, osa-miR1877 and osa-miR5799) were determined to be regulated by natural light/dark cycle. The expression level analysis showed that the four carbon and nitrogen metabolism-related miRNAs negatively regulated their target genes. These results may provide a good strategy to study how natural light/dark cycle regulates carbon and nitrogen metabolism to ensure plant growth and

  11. Growth versus metabolic tissue replacement in mouse tissues determined by stable carbon and nitrogen isotope analysis

    Science.gov (United States)

    Macavoy, S. E.; Jamil, T.; Macko, S. A.; Arneson, L. S.

    2003-12-01

    Stable isotope analysis is becoming an extensively used tool in animal ecology. The isotopes most commonly used for analysis in terrestrial systems are those of carbon and nitrogen, due to differential carbon fractionation in C3 and C4 plants, and the approximately 3‰ enrichment in 15N per trophic level. Although isotope signatures in animal tissues presumably reflect the local food web, analysis is often complicated by differential nutrient routing and fractionation by tissues, and by the possibility that large organisms are not in isotopic equilibrium with the foods available in their immediate environment. Additionally, the rate at which organisms incorporate the isotope signature of a food through both growth and metabolic tissue replacement is largely unknown. In this study we have assessed the rate of carbon and nitrogen isotopic turnover in liver, muscle and blood in mice following a diet change. By determining growth rates, we were able to determine the proportion of tissue turnover caused by growth versus that caused by metabolic tissue replacement. Growth was found to account for approximately 10% of observed tissue turnover in sexually mature mice (Mus musculus). Blood carbon was found to have the shortest half-life (16.9 days), followed by muscle (24.7 days). Liver carbon turnover was not as well described by the exponential decay equations as other tissues. However, substantial liver carbon turnover was observed by the 28th day after diet switch. Surprisingly, these tissues primarily reflect the carbon signature of the protein, rather than carbohydrate, source in their diet. The nitrogen signature in all tissues was enriched by 3 - 5‰ over their dietary protein source, depending on tissue type, and the isotopic turnover rates were comparable to those observed in carbon.

  12. Sugar-starvation-induced changes of carbon metabolism in excised maize root tips

    International Nuclear Information System (INIS)

    Dieuaide-Noubhani, M.; Canioni, P.; Raymond, P.

    1997-01-01

    Excised maize (Zea mays L.) root tips were used to study the early metabolic effects of glucose (Glc) starvation. Root tips were prelabeled with [1-13C]Glc so that carbohydrates and metabolic intermediates were close to steady-state labeling, but lipids and proteins were scarcely labeled. They were then incubated in a sugar-deprived medium for carbon starvation. Changes in the level of soluble sugars, the respiratory quotient, and the 13C enrichment of intermediates, as measured by 13C and 1H nuclear magnetic resonance, were studied to detect changes in carbon fluxes through glycolysis and the tricarboxylic acid cycle. Labeling of glutamate carbons revealed two major changes in carbon input into the tricarboxylic acid cycle: (a) the phosphoenolpyruvate carboxylase flux stopped early after the start of Glc starvation, and (b) the contribution of glycolysis as the source of acetyl-coenzyme A for respiration decreased progressively, indicating an increasing contribution of the catabolism of protein amino acids, fatty acids, or both. The enrichment of glutamate carbons gave no evidence for proteolysis in the early steps of starvation, indicating that the catabolism of proteins was delayed compared with that of fatty acids. Labeling of carbohydrates showed that sucrose turnover continues during sugar starvation, but gave no indication for any significant flux through gluconeogenesis

  13. The metabolism and dosimetry of carbon-14 labelled diethylenetriaminepentaacetic acid (DTPA)

    International Nuclear Information System (INIS)

    Crawley, F.E.H.; Haines, J.W.

    1978-01-01

    Male rats were given carbon-14 labelled Ca-DTPA either by intravenous injection or by pulmonary intubation. The elimination of the carbon-14 by excretion in urine, faeces and breath was followed, Chromatographic examination of the urine showed that no metabolic degradation of the 14 C-DTPA had occurred. The distribution of activity between lung, kidneys, bone, muscle and GI tract was also followed. The data obtained have been used to assess the radiation dose to man from an intake of 14 C-DTPA on the assumption that the behaviour of 14 C-DTPA in man is the same as in the rat. The results are discussed. (U K.)

  14. Abscisic acid as a factor in regulation of photosynthetic carbon metabolism of pea seedlings

    Directory of Open Access Journals (Sweden)

    Maria Faltynowicz

    2014-01-01

    Full Text Available The influence of abscisic acid (ABA on carbon metabolism and the activity of ribulosebisphosphate (RuBP and phosphoenolpyruvate (PEP carboxylases in 8-day-old pea seedlings was investigated. It was endeavoured to correlate the changes observed in metabolic processes with the endogenous ABA level. In plants treated with ABA incorporation of labeled carbon into sucrose, glucose, fructose and sugar phosphates was depressed, while 14C incorporation into starch, ribulose and malic acid was enhanced. The activity of RuBP carboxylase was considerably lowered, whereas that of PEP carboxylase was slightly increased. It is considered that inhibition of photosynthesis due to the action of ABA is caused to a great extent by the obstruction of the C-3 pathway and reduced activity of RuBP carboxylase, whereas (β-carboxylation was not blocked.

  15. 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 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.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.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.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.

  16. Spatially resolved metabolic analysis reveals a central role for transcriptional control in carbon allocation to wood.

    Science.gov (United States)

    Roach, Melissa; Arrivault, Stéphanie; Mahboubi, Amir; Krohn, Nicole; Sulpice, Ronan; Stitt, Mark; Niittylä, Totte

    2017-06-15

    The contribution of transcriptional and post-transcriptional regulation to modifying carbon allocation to developing wood of trees is not well defined. To clarify the role of transcriptional regulation, the enzyme activity patterns of eight central primary metabolism enzymes across phloem, cambium, and developing wood of aspen (Populus tremula L.) were compared with transcript levels obtained by RNA sequencing of sequential stem sections from the same trees. Enzymes were selected on the basis of their importance in sugar metabolism and in linking primary metabolism to lignin biosynthesis. Existing enzyme assays were adapted to allow measurements from ~1 mm3 sections of dissected stem tissue. These experiments provided high spatial resolution of enzyme activity changes across different stages of wood development, and identified the gene transcripts probably responsible for these changes. In most cases, there was a clear positive relationship between transcripts and enzyme activity. During secondary cell wall formation, the increases in transcript levels and enzyme activities also matched with increased levels of glucose, fructose, hexose phosphates, and UDP-glucose, emphasizing an important role for transcriptional regulation in carbon allocation to developing aspen wood. These observations corroborate the efforts to increase carbon allocation to wood by engineering gene regulatory networks. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  17. Metabolic engineering of carbon overflow metabolism of Bacillus subtilis for improved N-acetyl-glucosamine production.

    Science.gov (United States)

    Ma, Wenlong; Liu, Yanfeng; Shin, Hyun-Dong; Li, Jianghua; Chen, Jian; Du, Guocheng; Liu, Long

    2018-02-01

    Bacillus subtilis is widely used as cell factories for the production of important industrial biochemicals. Although many studies have demonstrated the effects of organic acidic byproducts, such as acetate, on microbial fermentation, little is known about the effects of blocking the neutral byproduct overflow, such as acetoin, on bioproduction. In this study, we focused on the influences of modulating overflow metabolism on the production of N-acetyl-d-glucosamine (GlcNAc) in engineered B. subtilis. We found that acetoin overflow competes with GlcNAc production, and blocking acetoin overflow increased GlcNAc titer and yield by 1.38- and 1.39-fold, reaching 48.9 g/L and 0.32 g GlcNAc/g glucose, respectively. Further blocking acetate overflow inhibited cell growth and GlcNAc production may be induced by inhibiting glucose uptake. Taken together, our results show that blocking acetoin overflow is a promising strategy for enhancing GlcNAc production. The strategies developed in this work may be useful for engineering strains of B. subtilis for producing other important biochemicals. Copyright © 2017. Published by Elsevier Ltd.

  18. 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 (...

  19. 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.

  20. 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.

  1. A deuterium and carbon nuclear magnetic resonance spectroscopic investigation of blood flow and carbohydrate metabolism

    International Nuclear Information System (INIS)

    Bosch, C.S.E.

    1988-01-01

    The purpose of this study is the development and application of nuclear magnetic resonance (NMR) spectroscopic techniques for this study of whole tissue metabolism, tissue perfusion and blood flow. The feasibility of spin imaging deuterium-enriched tissue water is demonstrated in cat brain in vivo and in situ. The potential application of D 2 O administration to deuterium-flow-imaging is considered. NMR investigations of hepatic carbohydrate metabolism were performed in rat liver in vivo and in situ. A coaxial, double-surface-coil, double-resonance probe was developed for carbon detection while decoupling neighboring proton scalar interactions ( 13 C-[ 1 H]) in hepatic tissue within the living animal. Hormonal and substrate regulation of hepatic glucose and glycogen metabolism was investigated by monitoring the metabolic fate of an administered c-dose of [1- 13 C]glucose. Label flux was directed primarily into newly-synthesized 13 C-labeled glycogen. A multiple resonance ( 1 H, 13 C, 31 P) liver perfusion probe was designed for complimentary carbohydrate metabolic studies in rat liver in vitro. A description of the 13 C-[ 1 H]/ 31 P NMR perfusion probe is given. The surgical technique used for liver excision and peripheral life-support apparatus required to maintain hepatic function are also detailed

  2. Photosystem II excitation pressure and photosynthetic carbon metabolism in Chlorella vulgaris

    International Nuclear Information System (INIS)

    Savitch, L.V.; Maxwell, D.P.; Huner, N.P.A.

    1996-01-01

    Chlorella vulgaris grown at 5 degrees C/150 micromoles m -2 s -1 mimics cells grown under high irradiance (27 degrees C/2200 micromoles m -2 s -1 ). This has been rationalized through the suggestion that both populations of cells were exposed to comparable photosystem II (PSII) excitation pressures measured as the chlorophyll a fluorescence quenching parameter, 1 - qP (D.P. Maxwell, S. Falk, N.P.A. Huner [1995] Plant Physiol 107: 687-694). To assess the possible role(s) of feedback mechanisms on PSII excitation pressure, stromal and cytosolic carbon metabolism were examined. Sucrose phosphate synthase and fructose-1,6-bisphosphatase activities as well as the ratios of fructose-1,6-bisphosphate/fructose-6 phosphate and sucrose/starch indicated that cells grown at 27 degrees C/2200 micromoles m -2 s -1 appeared to exhibit a restriction in starch metabolism. In contrast, cells grown at 5 degrees C/150 micromoles-1 m -2 s -1 appeared to exhibit a restriction in the sucrose metabolism based on decreased cytosolic fructose-1,6-bisphosphatase and sucrose phosphate synthase activities as well as a low sucrose/starch ratio. These metabolic restrictions may feedback on photosynthetic electron transport and, thus, contribute to the observed PSII excitation pressure. We conclude that, although PSII excitation pressure may reflect redox regulation of photosynthetic acclimation to light and temperature in C. vulgaris, it cannot be considered the primary redox signal. Alternative metabolic sensing/signaling mechanisms are discussed

  3. Benthic metabolic feedbacks to carbonate chemistry on coral reefs:implications for ocean acidification

    Science.gov (United States)

    Price, N.; Rohwer, F. L.; Stuart, S. A.; Andersson, A.; Smith, J.

    2012-12-01

    The metabolic activity of resident organisms can cause spatio-temporal variability in carbonate chemistry within the benthic boundary layer, and thus potentially buffer the global impacts of ocean acidification. But, little is known about the capacity for particular species assemblages to contribute to natural daily variability in carbonate chemistry. We encapsulated replicate areas (~3m2) of reef across six Northern Line Islands in the central Pacific for 24 hrs to quantify feedbacks to carbonate chemistry within the benthic boundary layer from community metabolism. Underneath each 'tent', we quantified relative abundance and biomass of each species of corals and algae. We coupled high temporal resolution time series data on the natural diurnal variability in pH, dissolved oxygen, salinity, and temperature (using autonomous sensors) with resident organisms' net community calcification and productivity rates (using change in total dissolved carbon and total alkalinity over time) to examine feedbacks from reef metabolism to boundary layer carbonate chemistry. These reefs experienced large ranges in pH (> 0.2 amplitude) each day, similar to the magnitude of 'acidification' expected over the next century. Daily benthic pH, pCO2, and aragonite saturation state (Ωaragonite) were contrasted with seasonal threshold values estimated from open ocean climatological data extrapolated at each island to determine relative inter-island feedbacks. Diurnal amplitude in pH, pCO2, and Ωaragonite at each island was dependent upon the resident species assemblage of the benthos and was particularly reliant upon the biomass, productivity, and calcification rate of Halimeda. Net primary productivity of fleshy algae (algal turfs and Lobophora spp.) predominated on degraded, inhabited islands where net community calcification was negligible. In contrast, the chemistry over reefs on 'pristine', uninhabited islands was driven largely by net calcification of calcareous algae and stony

  4. Beaver-mediated lateral hydrologic connectivity, fluvial carbon and nutrient flux, and aquatic ecosystem metabolism

    Science.gov (United States)

    Wegener, Pam; Covino, Tim; Wohl, Ellen

    2017-06-01

    River networks that drain mountain landscapes alternate between narrow and wide valley segments. Within the wide segments, beaver activity can facilitate the development and maintenance of complex, multithread planform. Because the narrow segments have limited ability to retain water, carbon, and nutrients, the wide, multithread segments are likely important locations of retention. We evaluated hydrologic dynamics, nutrient flux, and aquatic ecosystem metabolism along two adjacent segments of a river network in the Rocky Mountains, Colorado: (1) a wide, multithread segment with beaver activity; and, (2) an adjacent (directly upstream) narrow, single-thread segment without beaver activity. We used a mass balance approach to determine the water, carbon, and nutrient source-sink behavior of each river segment across a range of flows. While the single-thread segment was consistently a source of water, carbon, and nitrogen, the beaver impacted multithread segment exhibited variable source-sink dynamics as a function of flow. Specifically, the multithread segment was a sink for water, carbon, and nutrients during high flows, and subsequently became a source as flows decreased. Shifts in river-floodplain hydrologic connectivity across flows related to higher and more variable aquatic ecosystem metabolism rates along the multithread relative to the single-thread segment. Our data suggest that beaver activity in wide valleys can create a physically complex hydrologic environment that can enhance hydrologic and biogeochemical buffering, and promote high rates of aquatic ecosystem metabolism. Given the widespread removal of beaver, determining the cumulative effects of these changes is a critical next step in restoring function in altered river networks.

  5. Noninvasive assessment of canine myocardial oxidative metabolism with carbon-11 acetate and positron emission tomography

    International Nuclear Information System (INIS)

    Brown, M.A.; Myears, D.W.; Bergmann, S.R.

    1988-01-01

    Noninvasive quantification of regional myocardial metabolism would be highly desirable to evaluate pathogenetic mechanisms of heart disease and their response to therapy. It was previously demonstrated that the metabolism of radiolabeled acetate, a readily utilized myocardial substrate predominantly metabolized to carbon dioxide (CO2) by way of the tricarboxylic acid cycle, provides a good index of oxidative metabolism in isolated perfused rabbit hearts because of tight coupling between the tricarboxylic acid cycle and oxidative phosphorylation. In the present study, in a prelude to human studies, the relation between myocardial clearance of carbon-11 (11C)-labeled acetate and myocardial oxygen consumption was characterized in eight intact dogs using positron emission tomography. Anesthetized dogs were studied during baseline conditions and again during either high or low work states induced pharmacologically. High myocardial extraction and rapid blood clearance of tracer yielded myocardial images of excellent quality. The turnover (clearance) of 11C radioactivity from the myocardium was biexponential with the mean half-time of the dominant rapid phase averaging 5.4 +/- 2.2, 2.8 +/- 1.3 and 11.1 +/- 1.3 min in control, high and low work load studies, respectively. No significant difference was found between the rate of clearance of 11C radioactivity from the myocardium measured noninvasively with positron emission tomography and the myocardial efflux of 11CO2 measured directly from the coronary sinus. The rate of clearance of the 11C radioactivity from the heart correlated closely with myocardial oxygen consumption (r = 0.90, p less than 0.001) as well as with the rate-pressure product (r = 0.95, p less than 0.001). Hence, the rate of oxidation of 11C-acetate can be determined noninvasively with positron emission tomography, providing a quantitative index of oxidative metabolism under diverse conditions

  6. 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

  7. Inorganic carbon turnover caused by digestion of carbonate sands and metabolic activity of holothurians

    Science.gov (United States)

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

    2013-11-01

    Recent measurements have shown that holothurians (sea cucumbers) may play an important role in the cycling of CaCO3 in tropical coral reef systems through ingestion and processing of carbonate sediment. In this report, we present estimates of inorganic carbon turnover rates determined from laboratory incubations of Holothuria atra, Holothuria leucospilota and Stichopus herrmanni. The pH values of the gut lumen ranged from 7.0 to 7.6 when digestive tracts were filled with sediment compared with 6.1-6.7 in animals with empty digestive tracts. Empty gut volume estimates for H. atra and S. herrmanni were 36 ± 4 mL and 151 ± 14 mL, respectively. Based on these measurements and the density and porosity of carbonate sediments of coral reefs, it is estimated that these species process 19 ± 2 kg and 80 ± 7 kg CaCO3 sand yr-1 per individual, respectively. The annual CaCO3 dissolution rates per H. atra and S. herrmanni individual are estimated to be 6.5 ± 1.9 g and 9.6 ± 1.4 g, respectively, suggesting that 0.05 ± 0.02% and 0.1 ± 0.02% of the CaCO3 processed through their gut annually is dissolved. During incubations the CaCO3 dissolution of the fecal casts was 0.07 ± 0.01%, 0.04 ± 0.01% and 0.21 ± 0.05% for H. atra, H. leucospilota and S. herrmanni, respectively. The CaCO3 saturation state in the incubation seawater 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.

  8. Germany unveils €18bn research plan

    Science.gov (United States)

    Banks, Michael

    2009-07-01

    The German government has unveiled an ambitious plan to inject a total of €18bn into teaching and research over the next decade. The German chancellor Angela Merkel, who has a degree in physics, announced that she was releasing the funds despite concerns from her social-democrat coalition partners that financing the package could be difficult in the economic downturn.

  9. A DIGE analysis of developing poplar leaves subjected to ozone reveals major changes in carbon metabolism.

    Science.gov (United States)

    Bohler, Sacha; Bagard, Matthieu; Oufir, Mouhssin; Planchon, Sébastien; Hoffmann, Lucien; Jolivet, Yves; Hausman, Jean-François; Dizengremel, Pierre; Renaut, Jenny

    2007-05-01

    Tropospheric ozone pollution is described as having major negative effects on plants, compromising plant survival. Carbon metabolism is especially affected. In the present work, the effects of chronic ozone exposure were evaluated at the proteomic level in developing leaves of young poplar plants exposed to 120 ppb of ozone for 35 days. Soluble proteins (excluding intrinsic membrane proteins) were extracted from leaves after 3, 14 and 35 days of ozone exposure, as well as 10 days after a recovery period. Proteins (pI 4 to 7) were analyzed by 2-D DIGE experiments, followed by MALDI-TOF-TOF identification. Additional observations were obtained on growth, lesion formation, and leaf pigments analysis. Although treated plants showed large necrotic spots and chlorosis in mature leaves, growth decreased only slightly and plant height was not affected. The number of abscised leaves was higher in treated plants, but new leaf formation was not affected. A decrease in chlorophylls and lutein contents was recorded. A large number of proteins involved in carbon metabolism were identified. In particular, proteins associated with the Calvin cycle and electron transport in the chloroplast were down-regulated. In contrast, proteins associated with glucose catabolism increased in response to ozone exposure. Other identified enzymes are associated with protein folding, nitrogen metabolism and oxidoreductase activity.

  10. Transcriptome-based analysis on carbon metabolism of Haematococcus pluvialis mutant under 15% CO2.

    Science.gov (United States)

    Li, Ke; Cheng, Jun; Lu, Hongxiang; Yang, Weijuan; Zhou, Junhu; Cen, Kefa

    2017-06-01

    To elucidate the mechanism underlying the enhanced growth rate in the Haematococcus pluvialis mutated with 60 Co-γ rays and domesticated with 15% CO 2 , transcriptome sequencing was conducted to clarify the carbon metabolic pathways of mutant cells. The CO 2 fixation rate of mutant cells increased to 2.57gL -1 d -1 under 15% CO 2 due to the enhanced photosynthesis, carbon fixation, glycolysis pathways. The upregulation of PetH, ATPF0A and PetJ related to photosynthetic electron transport, ATP synthase and NADPH generation promoted the photosynthesis. The upregulation of genes related to Calvin cycle and ppdK promoted carbon fixation in both C3 and C4 photosynthetic pathways. The reallocation of carbon was also enhanced under 15% CO 2 . The 19-, 14- and 3.5-fold upregulation of FBA, TPI and PK genes, respectively, remarkably promoted the glycolysis pathways. This accelerated the conversion of photosynthetic carbon to pyruvate, which was an essential precursor for astaxanthin and lipids biosynthesis. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. 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).

  12. One-carbon metabolism, cognitive impairment and CSF measures of Alzheimer pathology: homocysteine and beyond.

    Science.gov (United States)

    Dayon, Loïc; Guiraud, Seu Ping; Corthésy, John; Da Silva, Laeticia; Migliavacca, Eugenia; Tautvydaitė, Domilė; Oikonomidi, Aikaterini; Moullet, Barbara; Henry, Hugues; Métairon, Sylviane; Marquis, Julien; Descombes, Patrick; Collino, Sebastiano; Martin, François-Pierre J; Montoliu, Ivan; Kussmann, Martin; Wojcik, Jérôme; Bowman, Gene L; Popp, Julius

    2017-06-17

    Hyperhomocysteinemia is a risk factor for cognitive decline and dementia, including Alzheimer disease (AD). Homocysteine (Hcy) is a sulfur-containing amino acid and metabolite of the methionine pathway. The interrelated methionine, purine, and thymidylate cycles constitute the one-carbon metabolism that plays a critical role in the synthesis of DNA, neurotransmitters, phospholipids, and myelin. In this study, we tested the hypothesis that one-carbon metabolites beyond Hcy are relevant to cognitive function and cerebrospinal fluid (CSF) measures of AD pathology in older adults. Cross-sectional analysis was performed on matched CSF and plasma collected from 120 older community-dwelling adults with (n = 72) or without (n = 48) cognitive impairment. Liquid chromatography-mass spectrometry was performed to quantify one-carbon metabolites and their cofactors. Least absolute shrinkage and selection operator (LASSO) regression was initially applied to clinical and biomarker measures that generate the highest diagnostic accuracy of a priori-defined cognitive impairment (Clinical Dementia Rating-based) and AD pathology (i.e., CSF tau phosphorylated at threonine 181 [p-tau181]/β-Amyloid 1-42 peptide chain [Aβ 1-42 ] >0.0779) to establish a reference benchmark. Two other LASSO-determined models were generated that included the one-carbon metabolites in CSF and then plasma. Correlations of CSF and plasma one-carbon metabolites with CSF amyloid and tau were explored. LASSO-determined models were stratified by apolipoprotein E (APOE) ε4 carrier status. The diagnostic accuracy of cognitive impairment for the reference model was 80.8% and included age, years of education, Aβ 1-42 , tau, and p-tau181. A model including CSF cystathionine, methionine, S-adenosyl-L-homocysteine (SAH), S-adenosylmethionine (SAM), serine, cysteine, and 5-methyltetrahydrofolate (5-MTHF) improved the diagnostic accuracy to 87.4%. A second model derived from plasma included cystathionine

  13. 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.

  14. Effects of physical characteristics of carbon black on metabolic regulation in mice

    International Nuclear Information System (INIS)

    Chuang, Hsiao-Chi; Hsiao, Ta-Chih; Lee, Chii-Hong; Chun-Te Lin, Justin; Chuang, Kai-Jen; Feng, Po-Hao; Cheng, Tsun-Jen

    2018-01-01

    Potential adverse effects of human exposure to carbon black (CB) have been reported, but limited knowledge regarding CB-regulated metabolism is currently available. To evaluate how physical parameters of CB influence metabolism, we investigated CB and diesel exhaust particles (DEPs) and attempted to relate various physical parameters, including the hydrodynamic diameter, zeta potential, and particle number concentrations, to lung energy metabolism in female BALB/c mice. A body weight increase was arrested by 3 months of exposure to CB of smaller-size fractions, which was negatively correlated with pyruvate in plasma. There were no significant differences in cytotoxic lactate dehydrogenase (LDH) or total protein in bronchoalveolar lavage fluid (BALF) after 3 months of CB exposure. However, we observed alterations in acetyl CoA and the NADP/NADPH ratio in lung tissues with CB exposure. Additionally, the NADP/NADPH ratio was associated with the zeta potential of CB. Mild peribronchiovascular and interstitial inflammation and multinucleated giant cells (macrophages) with a transparent and rhomboid appearance and containing foreign bodies were observed in lung sections. We suggest that physical characteristics of CB, such as the zeta potential, may disrupt metabolism after pulmonary exposure. These results, therefore, provide the first evidence of a link between pulmonary exposure to CB and metabolism. - Highlights: • We evaluated how physical parameters of CB influence metabolism in mice lungs. • Body weight was arrested by exposure to CB in mice. • CB-induced peribronchiovascular and interstitial inflammation in the lungs. • Disruption in functions of acetyl CoA and NADP/NADPH was observed in lungs. • NADP/NADPH ratio was associated with the zeta potentials of CB.

  15. New Perspectives on Acetate and One-Carbon Metabolism in the Methanoarchaea

    Energy Technology Data Exchange (ETDEWEB)

    Ferry, James [Pennsylvania State Univ., University Park, PA (United States)

    2017-03-20

    Carbonic anhydrases catalyze the reversible hydration of carbon dioxide to bicarbonate. Although widespread in prokaryotes of the domains Bacteria and Archaea, few have been investigated and the physiological functions are largely unknown. Carbonic anhydrases are of biotechnological interest for carbon dioxide capture and sequestration at point sources. Prokaryotes encode three independently evolved classes. The alpha-class is restricted to a few pathogens and the other two are uniformly distributed in phylogenetically and physiologically diverse species. Although wide-spread in prokaryotes, only three gamma-class enzymes have been biochemically characterized and the physiological functions have not been investigated. The gamma-class is prominent in anaerobic acetate-utilizing methane-producing species of the genus Methanosarcina that encode three subclasses. Enzymes from two of the subclasses, Cam and CamH from Methanosarcina thermophila, have been characterized and found to utilize iron in the active site which is the first example of an iron-containing carbonic anhydrase. No representative of the third subclass has been isolated, although this subclass constitutes the great majority of the β-class. This grant application proposed to characterize gamma-class carbonic anhydrases from diverse anaerobic prokaryotes from the domains Bacteria and Archaea to broaden the understanding of this enzyme. In particular, the three subclasses present the genetically tractable acetate-utilizing methanogen Methanosarcina acetivorans will be investigated to extend studies of acetate and one-carbon metabolism in this species. A genetic approach will be taken to ascertain the physiological functions. It is also proposed to delve deeper into the mechanism of Cam from M. thermophila, the archetype of the gamma-class, via a high resolution neutron structure and kinetic analysis of site-specific amino acid replacement variants. In the course of the investigation, goals were added to

  16. Effects of ocean acidification and hydrodynamic conditions on carbon metabolism and dissolved organic carbon (DOC) fluxes in seagrass populations.

    Science.gov (United States)

    Egea, Luis G; Jiménez-Ramos, Rocío; Hernández, Ignacio; Bouma, Tjeerd J; Brun, Fernando G

    2018-01-01

    Global change has been acknowledged as one of the main threats to the biosphere and its provision of ecosystem services, especially in marine ecosystems. Seagrasses play a critical ecological role in coastal ecosystems, but their responses to ocean acidification (OA) and climate change are not well understood. There have been previous studies focused on the effects of OA, but the outcome of interactions with co-factors predicted to alter during climate change still needs to be addressed. For example, the impact of higher CO2 and different hydrodynamic regimes on seagrass performance remains unknown. We studied the effects of OA under different current velocities on productivity of the seagrass Zostera noltei, using changes in dissolved oxygen as a proxy for the seagrass carbon metabolism, and release of dissolved organic carbon (DOC) in a four-week experiment using an open-water outdoor mesocosm. Under current pH conditions, increasing current velocity had a positive effect on productivity, but this depended on shoot density. However, this positive effect of current velocity disappeared under OA conditions. OA conditions led to a significant increase in gross production rate and respiration, suggesting that Z. noltei is carbon-limited under the current inorganic carbon concentration of seawater. In addition, an increase in non-structural carbohydrates was found, which may lead to better growing conditions and higher resilience in seagrasses subjected to environmental stress. Regarding DOC flux, a direct and positive relationship was found between current velocity and DOC release, both under current pH and OA conditions. We conclude that OA and high current velocity may lead to favourable growth scenarios for Z. noltei populations, increasing their productivity, non-structural carbohydrate concentrations and DOC release. Our results add new dimensions to predictions on how seagrass ecosystems will respond to climate change, with important implications for the

  17. Effects of ocean acidification and hydrodynamic conditions on carbon metabolism and dissolved organic carbon (DOC fluxes in seagrass populations.

    Directory of Open Access Journals (Sweden)

    Luis G Egea

    Full Text Available Global change has been acknowledged as one of the main threats to the biosphere and its provision of ecosystem services, especially in marine ecosystems. Seagrasses play a critical ecological role in coastal ecosystems, but their responses to ocean acidification (OA and climate change are not well understood. There have been previous studies focused on the effects of OA, but the outcome of interactions with co-factors predicted to alter during climate change still needs to be addressed. For example, the impact of higher CO2 and different hydrodynamic regimes on seagrass performance remains unknown. We studied the effects of OA under different current velocities on productivity of the seagrass Zostera noltei, using changes in dissolved oxygen as a proxy for the seagrass carbon metabolism, and release of dissolved organic carbon (DOC in a four-week experiment using an open-water outdoor mesocosm. Under current pH conditions, increasing current velocity had a positive effect on productivity, but this depended on shoot density. However, this positive effect of current velocity disappeared under OA conditions. OA conditions led to a significant increase in gross production rate and respiration, suggesting that Z. noltei is carbon-limited under the current inorganic carbon concentration of seawater. In addition, an increase in non-structural carbohydrates was found, which may lead to better growing conditions and higher resilience in seagrasses subjected to environmental stress. Regarding DOC flux, a direct and positive relationship was found between current velocity and DOC release, both under current pH and OA conditions. We conclude that OA and high current velocity may lead to favourable growth scenarios for Z. noltei populations, increasing their productivity, non-structural carbohydrate concentrations and DOC release. Our results add new dimensions to predictions on how seagrass ecosystems will respond to climate change, with important

  18. Metabolism

    Science.gov (United States)

    ... Are More Common in People With Type 1 Diabetes Metabolic Syndrome Your Child's Weight Healthy Eating Endocrine System Blood Test: Basic Metabolic Panel (BMP) Activity: Endocrine System Growth Disorders Diabetes Center Thyroid Disorders Your Endocrine System Movie: Endocrine ...

  19. The Role of Diet in One-Carbon Metabolism and Epigenetics

    DEFF Research Database (Denmark)

    Lind, Mads Vendelbo

    Background: Dysregulation of one-carbon metabolism (OCM) is related to metabolic syndrome (MetS) through various mechanisms including epigenetics. Diet plays a central role in ensuring normal OCM regulation by supplying multiple nutrients. Foods such as whole grains and fish have been proposed...... acid (EPA) and docosahexaenoic acid (DHA) which might also play a role in OCM regulation and epigenetics. Aim: This PhD thesis investigates the role of diet in OCM regulation and the potential association between OCM and MetS. We further investigated whether a dietary intervention with high whole grain......-adenosylmethionine (SAM), s-adenosylhomocysteine (SAH) and Hcy, and diet. Associations between OCM metabolites and MetS features were also investigated. In an 8-week human cross-over intervention study we investigated whether a diet rich in whole grain compared to a diet rich in refined grain could affect OCM metabolites...

  20. Changes in bone sodium and carbonate in metabolic acidosis and alkalosis in the dog

    Science.gov (United States)

    Burnell, James M.

    1971-01-01

    Metabolic acidosis and alkalosis were produced in adult dogs over 5- to 10-day periods. Midtibial cortical bone was analyzed for calcium, sodium, phosphorus, and carbonate. In acidosis bone CO3/Ca decreased 9.5% and bone Na/Ca decreased 6.3%. In alkalosis bone CO3/Ca increased 3.1% and bone Na/Ca increased 3.0%. Previous attempts to account for changes in net acid balance by summation of extra- and intracellular acid-base changes have uniformly resulted in about 40-60% of acid gained or lost being “unaccounted for.” If it is assumed that changes in tibial cortex reflect changes in the entire skeletal system, changes in bone CO3= are sufficiently large to account for the “unaccounted for” acid change without postulating changes in cellular metabolic acid production. PMID:5540172

  1. 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

  2. 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...... and hyperventilation with single-photon emission computed tomography (SPECT) (14 patients) and/or the Kety-Schmidt technique (KS) (11 patients and all controls). In KS studies, CMR was measured by multiplying the arterial to jugular venous concentration difference (a-v D) by CBF. RESULTS: CBF did not differ...

  3. Possible role for abscisic acid in regulation of photosynthetic and photorespiratory carbon metabolism in barley leaves

    International Nuclear Information System (INIS)

    Popova, L.P.; Tsonev, T.D.; Vaklinova, S.G.

    1987-01-01

    The influence of abscisic acid (ABA) on carbon metabolism, rate of photorespiration, and the activity of the photorespiratory enzymes ribulose bisphosphate oxygenase and glycolate oxidase in 7-day-old barley seedlings (Hordeum vulgare L. var. Alfa) was investigated. Plants treated with ABA had enhanced incorporation of labeled carbon from 14 CO 2 into glycolic acid, glycine, and serine, while 14 C incorporation into 3-phosphoglyceric acid and sugarphosphate esters was depressed. Parallel with this effect, treated plants showed a rise in activity of RuBP oxygenase and glycolic acid oxidase. The rate of photorespiration was increased twofold by ABA treatment at IO -6 molar while the CO 2 -compensation point increased 46% and stomatal resistance increased more than twofold over control plants

  4. Initial water deficit effects on Lupinus albus photosynthetic performance, carbon metabolism, and hormonal balance: metabolic reorganization prior to early stress responses

    Czech Academy of Sciences Publication Activity Database

    Pinheiro, C.; António, C.; Dobrev, Petre; Vaňková, Radomíra; Wilson, J. C.

    2011-01-01

    Roč. 62, č. 14 (2011), s. 4965-4974 ISSN 0022-0957 Institutional research plan: CEZ:AV0Z50380511 Keywords : Carbon metabolism * hormone balance * LC-MS Subject RIV: EF - Botanics Impact factor: 5.364, year: 2011

  5. Carbon isotopic patterns of amino acids associated with various microbial metabolic pathways and physiological conditions

    Science.gov (United States)

    Wang, P. L.; Hsiao, K. T.; Lin, L. H.

    2017-12-01

    Amino acids represent one of the most important categories of biomolecule. Their abundance and isotopic patterns have been broadly used to address issues related to biochemical processes and elemental cycling in natural environments. Previous studies have shown that various carbon assimilative pathways of microorganisms (e.g. autotrophy, heterotrophy and acetotrophy) could be distinguished by carbon isotopic patterns of amino acids. However, the taxonomic and catabolic coverage are limited in previous examination. This study aims to uncover the carbon isotopic patterns of amino acids for microorganisms remaining uncharacterized but bearing biogeochemical and ecological significance in anoxic environments. To fulfill the purpose, two anaerobic strains were isolated from riverine wetland and mud volcano in Taiwan. One strain is a sulfate reducing bacterium (related to Desulfovibrio marrakechensis), which is capable of utilizing either H2 or lactate, and the other is a methanogen (related to Methanolobus profundi), which grows solely with methyl-group compounds. Carbon isotope analyses of amino acids were performed on cells grown in exponential and stationary phase. The isotopic patterns were similar for all examined cultures, showing successive 13C depletion along synthetic pathways. No significant difference was observed for the methanogen and lactate-utilizing sulfate reducer harvested in exponential and stationary phases. In contrast, the H2-utilizing sulfate reducer harvested in stationary phase depleted and enriched 13C in aspartic acid and glycine, respectively when compared with that harvested in exponential phase. Such variations might infer the change of carbon flux during synthesis of these two amino acids in the reverse TCA cycle. In addition, the discriminant function analysis for all available data from culture studies further attests the capability of using carbon isotope patterns of amino acids in identifying microbial metabolisms.

  6. A natural light/dark cycle regulation of carbon-nitrogen metabolism and gene expression in rice shoots

    Directory of Open Access Journals (Sweden)

    Haixing Li

    2016-08-01

    Full Text Available Light and temperature are two particularly important environmental cues for plant survival. Carbon and nitrogen are two essential macronutrients required for plant growth and development, and cellular carbon and nitrogen metabolism must be tightly coordinated. In order to understand how the natural light/dark cycle regulates carbon and nitrogen metabolism in rice plants, we analyzed the photosynthesis, key carbon-nitrogen metabolites and enzyme activities, and differentially expressed genes and miRNAs involved in the carbon and nitrogen metabolic pathway in rice shoots at the following times: 2:00, 6:00, 10:00, 14:00, 18:00 and 22:00. Our results indicated that more CO2 was fixed into carbohydrates by a high net photosynthetic rate, respiratory rate and stomatal conductance in the daytime. Although high levels of the nitrate reductase activity, free ammonium and carbohydrates were exhibited in the daytime, the protein synthesis was not significantly facilitated by the light and temperature. In mRNA sequencing, the carbon and nitrogen metabolism-related differentially expressed genes were obtained, which could be divided into eight groups: photosynthesis, TCA cycle, sugar transport, sugar metabolism, nitrogen transport, nitrogen reduction, amino acid metabolism and nitrogen regulation. Additionally, a total of 78,306 alternative splicing events have been identified, which primarily belong to alternative 5' donor sites, alternative 3' acceptor sites, intron retention and exon skipping. In sRNA sequencing, four carbon and nitrogen metabolism-related miRNAs (osa-miR1440b, osa-miR2876-5p, osa-miR1877 and osa-miR5799 were determined to be regulated by natural light/dark cycle. The expression level analysis showed that the four carbon and nitrogen metabolism-related miRNAs negatively regulated their target genes. These results may provide a good strategy to study how natural light/dark cycle regulates carbon and nitrogen metabolism to ensure plant

  7. Cash boost to Great British science unveiled

    CERN Multimedia

    2002-01-01

    "Trade and Industry Secretary, Patricia Hewitt today unveiled new plans for the DTI's record science budget over the next three years, to keep Britain at the forefront of world science. The plans include funding to develop life saving new health techniques, to seek alternative energy sources, to help our rural economy, to develop the computers of tomorrow and boost business with the next generation of leading edge technologies" (1 page).

  8. (Carbon and hydrogen metabolism of green algae in light and dark)

    Energy Technology Data Exchange (ETDEWEB)

    1990-01-01

    The focus of this project was the elucidation of anaerobic metabolism in ecuaryotic green algae, chlamydomonas reinhardii. Chlamydomonas is a versatile organism that can grow under disparate conditions such as fresh water lakes and sewage ponds. The cell an photoassimilate CO{sub 2} aerobically and anaerobically, the latter after adaptation'' to a hydrogen metabolism. It can recall the knallgas or oxyhydrogen reaction and utilize hydrogen the simplest of all reducing agents for the dark assimilation of CO{sub 2} by the photosynthetic carbon reduction cycle. The dark reduction with hydrogen lies on the border line between autotrophic and heterotrophic carbon assimilation. Both autotrophic and heterotrophic bacteria are known in which molecular hydrogen can replace either inorganic or organic hydrogen donors. Here the dark reduction of CO{sub 2} acquires a particular importance since it occurs in the same cell that carries on photoreduction and photosynthesis. We will demonstrate here that the alga chloroplast possesses a respiratory capacity. It seems likely that Chlamydomonas may have retained the chloroplastic respiratory pathway because of the selective advantage provided to the algae under a wide range of environmental conditions that the cells experience in nature. The ability to cycle electrons and poise the reduction level of the photosynthetic apparatus under aerobic and microaerobic conditions could allow more efficient CO{sub 2} fixation and enhanced growth under unfavorable conditions or survival under more severe conditions.

  9. Metformin regulates global DNA methylation via mitochondrial one-carbon metabolism.

    Science.gov (United States)

    Cuyàs, E; Fernández-Arroyo, S; Verdura, S; García, R Á-F; Stursa, J; Werner, L; Blanco-González, E; Montes-Bayón, M; Joven, J; Viollet, B; Neuzil, J; Menendez, J A

    2018-02-15

    The anti-diabetic biguanide metformin may exert health-promoting effects via metabolic regulation of the epigenome. Here we show that metformin promotes global DNA methylation in non-cancerous, cancer-prone and metastatic cancer cells by decreasing S-adenosylhomocysteine (SAH), a strong feedback inhibitor of S-adenosylmethionine (SAM)-dependent DNA methyltransferases, while promoting the accumulation of SAM, the universal methyl donor for cellular methylation. Using metformin and a mitochondria/complex I (mCI)-targeted analog of metformin (norMitoMet) in experimental pairs of wild-type and AMP-activated protein kinase (AMPK)-, serine hydroxymethyltransferase 2 (SHMT2)- and mCI-null cells, we provide evidence that metformin increases the SAM:SAH ratio-related methylation capacity by targeting the coupling between serine mitochondrial one-carbon flux and CI activity. By increasing the contribution of one-carbon units to the SAM from folate stores while decreasing SAH in response to AMPK-sensed energetic crisis, metformin can operate as a metabolo-epigenetic regulator capable of reprogramming one of the key conduits linking cellular metabolism to the DNA methylation machinery.

  10. Partitioning of Intermediary Carbon Metabolism in Vesicular-Arbuscular Mycorrhizal Leek.

    Science.gov (United States)

    Shachar-Hill, Y.; Pfeffer, P. E.; Douds, D.; Osman, S. F.; Doner, L. W.; Ratcliffe, R. G.

    1995-05-01

    Vesicular-arbuscular mycorrhizal fungi are symbionts for a large variety of crop plants; however, the form in which they take up carbon from the host is not established. To trace the course of carbon metabolism, we have used nuclear magnetic resonance spectroscopy with [13C]glucose labeling in vivo and in extracts to examine leek (Allium porrum) roots colonized by Glomus etunicatum (and uncolonized controls) as well as germinating spores. These studies implicate glucose as a likely substrate for vesicular-arbuscular mycorrhizal fungi in the symbiotic state. Root feeding of 0.6 mM 1-[13C]glucose labeled only the fungal metabolites trehalose and glycogen. The time course of this labeling was dependent on the status of the host. Incubation with 50 mM 1-[13C]glucose caused labeling of sucrose (in addition to fungal metabolites) with twice as much labeling in uncolonized plants. There was no detectable scrambling of the label from C1 glucose to the C6 position of glucose moieties in trehalose or glycogen. Labeling of mannitol C1,6 in the colonized root tissue was much less than in axenically germinating spores. Thus, carbohydrate metabolism of host and fungus are significantly altered in the symbiotic state.

  11. Nutrition, One-Carbon Metabolism and Neural Tube Defects: A Review

    Directory of Open Access Journals (Sweden)

    Kelei Li

    2016-11-01

    Full Text Available Neural tube defects (NTDs are a group of severe congenital malformations, induced by the combined effects of genes and the environment. The most valuable finding so far has been the protective effect of folic acid supplementation against NTDs. However, many women do not take folic acid supplements until they are pregnant, which is too late to prevent NTDs effectively. Long-term intake of folic acid–fortified food is a good choice to solve this problem, and mandatory folic acid fortification should be further promoted, especially in Europe, Asia and Africa. Vitamin B2, vitamin B-6, vitamin B-12, choline, betaine and n-3 polyunsaturated fatty acids (PUFAs can also reduce the NTD risk by interacting with the one-carbon metabolism pathway. This suggest that multivitamin B combined with choline, betaine and n-3 PUFAs supplementation may have a better protective effect against NTDs than folic acid alone. Genetic polymorphisms involved in one-carbon metabolism are associated with NTD risk, and gene screening for women of childbearing age prior to pregnancy may help prevent NTDs induced by the risk allele. In addition, the consumption of alcohol, tea and coffee, and low intakes of fruit and vegetable are also associated with the increased risk of NTDs, and should be avoided by women of childbearing age.

  12. Arsenic methylation capacity in relation to nutrient intake and genetic polymorphisms in one-carbon metabolism.

    Science.gov (United States)

    Gamboa-Loira, Brenda; Hernández-Alcaraz, César; Gandolfi, A Jay; Cebrián, Mariano E; Burguete-García, Ana; García-Martínez, Angélica; López-Carrillo, Lizbeth

    2018-07-01

    Nutrients and genetic polymorphisms participating in one-carbon metabolism may explain interindividual differences in inorganic arsenic (iAs) methylation capacity, which in turn may account for variations in susceptibility to iAs-induced diseases. 1) To evaluate the association between polymorphisms in five one-carbon metabolism genes (FOLH1 c.223 T > C, MTHFD1 c.1958 G > A, MTHFR c.665 C > T, MTR c.2756 A > G, and MTRR c.66 A > G) and iAs methylation capacity; 2) To assess if previously reported associations between nutrient intake and iAs methylation capacity are modified by those polymorphisms. Women (n = 1027) exposed to iAs in Northern Mexico were interviewed. Blood and urine samples were collected. Nutrient dietary intake was estimated using a validated food frequency questionnaire. iAs methylation capacity was calculated from urinary iAs species (iAs, monomethylarsonic acid [MMA] and dimethylarsinic acid [DMA]) measured by high performance liquid chromatography (HPLC-ICP-MS). One polymorphism in each of the five genes evaluated was genotyped by allelic discrimination. Multivariable linear regression models were used to evaluate if genetic polymorphisms modified the associations between iAs methylation capacity parameters and nutrient intake. The median (min-max) concentration of total arsenic (TAs) was 20.2 (1.3-2776.0) µg/g creatinine in the study population. Significant interactions for iAs metabolism were only found with FOLH1 c.223 T > C polymorphism and vitamin B12 intake, so that CT and CC genotype carriers had significantly lower %iAs, and higher DMA/iAs with an increased vitamin B12 intake, as compared to carriers of wild-type TT. Differences in dietary nutrient intake and genetic variants in one-carbon metabolism may jointly influence iAs methylation capacity. Confirmation of these interactions in other populations is warranted. Copyright © 2018 Elsevier Inc. All rights reserved.

  13. Prognosis of breast cancer is associated with one-carbon metabolism related nutrients among Korean women

    Directory of Open Access Journals (Sweden)

    Lee Yunhee

    2012-08-01

    Full Text Available Abstract Background The 5-year survival rate for breast cancer among Korean women has increased steadily; however, breast cancer remains the leading cause of cancer mortality among women. One-carbon metabolism, which requires an adequate supply of methyl group donors and B vitamins, may affect the prognosis of breast cancer. This aim of this study was to investigate the associations of dietary intake of vitamin B2, vitamin B6 and folate before diagnosis on the prognosis of breast cancer. Methods We assessed the dietary intake using a food frequency questionnaire with 980 women who were newly diagnosed and histopathologically confirmed to have primary breast cancer from hospitals in Korea, and 141 disease progression events occurred. Cox’s proportional hazard regression models were used to estimate the hazard ratio (HR and 95% confidence interval (95% CI adjusting for age, education, recruitment sites, TNM stage, hormone status, nuclear grade and total calorie. Results There was no significant association between any one-carbon metabolism related nutrients (vitamin B2, B6 and folate and the progression of breast cancer overall. However, one-carbon metabolism related nutrients were associated with disease progression in breast cancer patients stratified by subtypes. In ER + and/or PR + breast cancers, no association was observed; however, in ER–/PR– breast cancers, a high intake of vitamin B2 and folate statistically elevated the HR of breast cancer progression (HR = 2.28; 95% CI, 1.20-4.35, HR = 1.84; 95% CI, 1.02-3.32, respectively compared to a low intake. This positive association between the ER/PR status and progression of the disease was profound when the nutrient intakes were categorized in a combined score (Pinteraction = 0.018. In ER–/PR– breast cancers, high combined scores were associated with a significantly poor DFS compared to those belonging to the low score group (HR = 3.84; 95% CI, 1

  14. Differential Metabolism of a Two-Carbon Substrate by Members of the Paracoccidioides Genus

    Directory of Open Access Journals (Sweden)

    Lilian C. Baeza

    2017-11-01

    Full Text Available The genus Paracoccidioides comprises known fungal pathogens of humans and can be isolated from different infection sites. Metabolic peculiarities in different members of the Paracoccidioides led us to perform proteomic studies in the presence of the two-carbon molecule acetate, which predominates in the nutrient-poor environment of the phagosome. To investigate the expression rates of proteins of different members of Paracoccidioides, including one isolate of P. lutzii (Pb01 and three isolates of P. brasiliensis (Pb03, Pb339, and PbEPM83, using sodium acetate as a carbon source, proteins were quantified using label-free and data-independent liquid chromatography-mass spectrometry. Protein profiles of the isolates were statistically analyzed, revealing proteins that were differentially expressed when the fungus was cultivated in a non-preferential carbon source rather than glucose. A total of 1,160, 1,211, 1,280, and 1,462 proteins were reproducibly identified and relatively quantified in P. lutzii and the P. brasiliensis isolates Pb03, Pb339, and PbEPM83, respectively. Notably, 526, 435, 744, and 747 proteins were differentially expressed among P. lutzii and the P. brasiliensis isolates Pb03, Pb339, and PbEPM83, respectively, with a fold-change equal to or higher than 1.5. This analysis revealed that reorganization of metabolism occurred through the induction of proteins related to gluconeogenesis, glyoxylic/glyoxylate cycle, response to stress, and degradation of amino acids in the four isolates. The following differences were observed among the isolates: higher increases in the expression levels of proteins belonging to the TCA and respiratory chain in PbEPM83 and Pb01; increase in ethanol production in Pb01; utilization of cell wall components for gluconeogenesis in Pb03 and PbEPM83; and increased β-oxidation and methylcitrate cycle proteins in Pb01and PbEPM83. Proteomic profiles indicated that the four isolates reorganized their metabolism

  15. Fasting ameliorates metabolism, immunity, and oxidative stress in carbon tetrachloride-intoxicated rats.

    Science.gov (United States)

    Sadek, Km; Saleh, Ea

    2014-12-01

    Fasting has been recently discovered to improve overall health, but its beneficial effects in the presence of hepatic insufficiency have not been proven. The influence of fasting on the metabolism, immunological aspects, and oxidative stress of 40 male carbon tetrachloride (CCl4)-intoxicated Wistar rats was investigated in the present study. The rats were divided into four groups, including a placebo group, CCl4-intoxicated rats, which were injected subcutaneously with 1.0 ml/kg of CCl4 solution, a fasting group, which was fasted 12 h/day for 30 days, and a fourth group, which was injected with CCl4 and fasted. The metabolism, immunity, and oxidative stress improved in CCl4-intoxicated rats fasted for 12 h/day for 30 days, as evidenced in significant increase (p fasting improved metabolism, immunity, and oxidative stress in CCl4-intoxicated rats. Thus, fasting during Ramadan is safe for patients with hepatic disorders, as the prophet Mohammed (S) said "Keep the fast, keep your health". © The Author(s) 2014.

  16. Metabolic distress in lipid & one carbon metabolic pathway through low vitamin B-12: a population based study from North India.

    Science.gov (United States)

    Saraswathy, Kallur Nava; Joshi, Shipra; Yadav, Suniti; Garg, Priyanka Rani

    2018-04-25

    population is vulnerable to severe under-nutrition due to the association of vitamin B-12 with HDL, leading to metabolic disturbance in both the pathways; lipid and one carbon metabolic pathway. Co-factors such as ethnicity, cultural practices, and lifestyle & dietary habits must be considered while making public health policies to control diseases.

  17. Carbon conversion efficiency and central metabolic fluxes in developing sunflower (Helianthus annuus L.) embryos.

    Science.gov (United States)

    Alonso, Ana P; Goffman, Fernando D; Ohlrogge, John B; Shachar-Hill, Yair

    2007-10-01

    The efficiency with which developing sunflower embryos convert substrates into seed storage reserves was determined by labeling embryos with [U-(14)C6]glucose or [U-(14)C5]glutamine and measuring their conversion to CO2, oil, protein and other biomass compounds. The average carbon conversion efficiency was 50%, which contrasts with a value of over 80% previously observed in Brassica napus embryos (Goffman et al., 2005), in which light and the RuBisCO bypass pathway allow more efficient conversion of hexose to oil. Labeling levels after incubating sunflower embryos with [U-(14)C4]malate indicated that some carbon from malate enters the plastidic compartment and contributes to oil synthesis. To test this and to map the underlying pattern of metabolic fluxes, separate experiments were carried out in which embryos were labeled to isotopic steady state using [1-(13)C1]glucose, [2-(13)C1]glucose, or [U-(13)C5]glutamine. The resultant labeling in sugars, starch, fatty acids and amino acids was analyzed by NMR and GC-MS. The fluxes through intermediary metabolism were then quantified by computer-aided modeling. The resulting flux map accounted well for the labeling data, was in good agreement with the observed carbon efficiency, and was further validated by testing for agreement with gas exchange measurements. The map shows that the influx of malate into oil is low and that flux through futile cycles (wasting ATP) is low, which contrasts with the high rates previously determined for growing root tips and heterotrophic cell cultures.

  18. Partitioning of One-Carbon Units in Folate and Methionine Metabolism Is Essential for Neural Tube Closure

    Directory of Open Access Journals (Sweden)

    Kit-Yi Leung

    2017-11-01

    Full Text Available Summary: Abnormal folate one-carbon metabolism (FOCM is implicated in neural tube defects (NTDs, severe malformations of the nervous system. MTHFR mediates unidirectional transfer of methyl groups from the folate cycle to the methionine cycle and, therefore, represents a key nexus in partitioning one-carbon units between FOCM functional outputs. Methionine cycle inhibitors prevent neural tube closure in mouse embryos. Similarly, the inability to use glycine as a one-carbon donor to the folate cycle causes NTDs in glycine decarboxylase (Gldc-deficient embryos. However, analysis of Mthfr-null mouse embryos shows that neither S-adenosylmethionine abundance nor neural tube closure depend on one-carbon units derived from embryonic or maternal folate cycles. Mthfr deletion or methionine treatment prevents NTDs in Gldc-null embryos by retention of one-carbon units within the folate cycle. Overall, neural tube closure depends on the activity of both the methionine and folate cycles, but transfer of one-carbon units between the cycles is not necessary. : Leung at al. find that embryonic neural tube closure depends both on the supply of one-carbon units to the folate cycle from glycine cleavage and on the methionine cycle. In contrast, transfer of one-carbon units from the folate cycle to the methionine cycle by MTHFR is dispensable. Keywords: one-carbon metabolism, folic acid, neural tube defects, spina bifida, glycine cleavage system, non-ketotic hyperglycinemia, eye, Mthfr, Gldc

  19. Up-regulation of sucrose metabolizing enzymes in Oncidium goldiana grown under elevated carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Chang Run Li; Sun, W.Q.; Choy Sin Hew [National Univ. of Singapore. dept. of Biological Sciences (Singapore)

    2001-07-01

    Experiments were conducted in controlled growth chambers to evaluate how increase in CO{sub 2} concentration affected sucrose metabolizing enzymes, especially sucrose phosphate synthase (SPS; EC 2.4.1.14) and sucrose synthase (SS; EC 2.4.1.13), as well as carbon metabolism and partitioning in a tropical epiphytic orchid species (Oncidium goldiana). Response of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco; EC 4.1.1.39) to elevated CO{sub 2} was determined along with dry mass production, photosynthesis rate, chlorophyll content, total nitrogen and total soluble protein content. After 60 days of growth, there was a 80% and 150% increase in dry mass production in plants grown at 750 and 1100 {mu} l{sup -}1 CO{sub 2}, respectively, compared with those grown at ambient CO{sub 2} (about 370 {mu} l{sup -}1). A similar increase in photosynthesis rate was detected throughout the growth period when measured under growth CO{sub 2} conditions. Concomitantly, there was a decline in leaf Rubisco activity in plants in elevated CO{sub 2} after 10 days of growth. Over the growth period, leaf SPS and SS activities were up-regulated by an average of 20% and 40% for plants grown at 750 and 1100 {mu} l{sup -}1 CO{sub 2}, respectively. Leaf sucrose content and starch content were significantly higher throughout the growth period in plants grown at elevated CO{sub 2} than those at ambient CO{sub 2}. The partitioning of photosynthetically fixed carbon between sucrose and starch appeared to be unaffected by the 750 {mu} l{sup -}1 CO{sub 2} treatment, but it was favored into starch under the 1100 {mu} l{sup -}1 CO{sub 2} condition. The activities of SPS and SS in leaf extracts were closely associated with photosynthetic rates and with partitioning of carbon between starch and sucrose in leaves. The data are consistent with the hypothesis that the up-regulation of leaf SPS and SS might be an acclimation response to optimize the utilization and export of organic carbon with the

  20. Metabolism

    Science.gov (United States)

    ... lin), which signals cells to increase their anabolic activities. Metabolism is a complicated chemical process, so it's not ... how those enzymes or hormones work. When the metabolism of body chemicals is ... Hyperthyroidism (pronounced: hi-per-THIGH-roy-dih-zum). Hyperthyroidism ...

  1. Metabolic Pathways Involved in Carbon Dioxide Enhanced Heat Tolerance in Bermudagrass

    Directory of Open Access Journals (Sweden)

    Jingjin Yu

    2017-09-01

    Full Text Available Global climate changes involve elevated temperature and CO2 concentration, imposing significant impact on plant growth of various plant species. Elevated temperature exacerbates heat damages, but elevated CO2 has positive effects on promoting plant growth and heat tolerance. The objective of this study was to identify metabolic pathways affected by elevated CO2 conferring the improvement of heat tolerance in a C4 perennial grass species, bermudagrass (Cynodon dactylon Pers.. Plants were planted under either ambient CO2 concentration (400 μmol⋅mol-1 or elevated CO2 concentration (800 μmol⋅mol-1 and subjected to ambient temperature (30/25°C, day/night or heat stress (45/40°C, day/night. Elevated CO2 concentration suppressed heat-induced damages and improved heat tolerance in bermudagrass. The enhanced heat tolerance under elevated CO2 was attributed to some important metabolic pathways during which proteins and metabolites were up-regulated, including light reaction (ATP synthase subunit and photosystem I reaction center subunit and carbon fixation [(glyceraldehyde-3-phosphate dehydrogenase, GAPDH, fructose-bisphosphate aldolase, phosphoglycerate kinase, sedoheptulose-1,7-bisphosphatase and sugars of photosynthesis, glycolysis (GAPDH, glucose, fructose, and galactose and TCA cycle (pyruvic acid, malic acid and malate dehydrogenase of respiration, amino acid metabolism (aspartic acid, methionine, threonine, isoleucine, lysine, valine, alanine, and isoleucine as well as the GABA shunt (GABA, glutamic acid, alanine, proline and 5-oxoproline. The up-regulation of those metabolic processes by elevated CO2 could at least partially contribute to the improvement of heat tolerance in perennial grass species.

  2. Photochemical alteration of organic carbon draining permafrost soils shifts microbial metabolic pathways and stimulates respiration.

    Science.gov (United States)

    Ward, Collin P; Nalven, Sarah G; Crump, Byron C; Kling, George W; Cory, Rose M

    2017-10-03

    In sunlit waters, photochemical alteration of dissolved organic carbon (DOC) impacts the microbial respiration of DOC to CO 2 . This coupled photochemical and biological degradation of DOC is especially critical for carbon budgets in the Arctic, where thawing permafrost soils increase opportunities for DOC oxidation to CO 2 in surface waters, thereby reinforcing global warming. Here we show how and why sunlight exposure impacts microbial respiration of DOC draining permafrost soils. Sunlight significantly increases or decreases microbial respiration of DOC depending on whether photo-alteration produces or removes molecules that native microbial communities used prior to light exposure. Using high-resolution chemical and microbial approaches, we show that rates of DOC processing by microbes are likely governed by a combination of the abundance and lability of DOC exported from land to water and produced by photochemical processes, and the capacity and timescale that microbial communities have to adapt to metabolize photo-altered DOC.The role of dissolved organic carbon (DOC) photo-alteration in the microbial respiration of DOC to CO 2 is unclear. Here, the authors show that the impact of this mechanism depends on whether photo-alteration of DOC produces or removes molecules used by native microbial communities prior to light exposure.

  3. Direct monitoring by carbon-13 nuclear magnetic resonance spectroscopy of the metabolism and metabolic rate of 13C-labeled compounds in vivo.

    Science.gov (United States)

    Iida, K; Hidoh, O; Fukami, J; Kajiwara, M

    1991-01-01

    Carbon-13 nuclear magnetic resonance spectroscopy has been used to observe the transformations of [1-13C]-D-glucose to [1,1'-13C2]-D-trehalose, and [3-13C]-L-alanine to [2-13C]-L-glutamic acid in the living body of Gryllodes sigillatus. [3-13C]-D-Alanine was not metabolized. The metabolic rate of [1-13C]-D-glucose was found to be altered by prior injection of boric acid.

  4. Carbon Source-Dependent Inducible Metabolism of Veratryl Alcohol and Ferulic Acid in Pseudomonas putida CSV86

    Science.gov (United States)

    Mohan, Karishma

    2017-01-01

    ABSTRACT Pseudomonas putida CSV86 degrades lignin-derived metabolic intermediates, viz., veratryl alcohol, ferulic acid, vanillin, and vanillic acid, as the sole sources of carbon and energy. Strain CSV86 also degraded lignin sulfonate. Cell respiration, enzyme activity, biotransformation, and high-pressure liquid chromatography (HPLC) analyses suggest that veratryl alcohol and ferulic acid are metabolized to vanillic acid by two distinct carbon source-dependent inducible pathways. Vanillic acid was further metabolized to protocatechuic acid and entered the central carbon pathway via the β-ketoadipate route after ortho ring cleavage. Genes encoding putative enzymes involved in the degradation were found to be present at fer, ver, and van loci. The transcriptional analysis suggests a carbon source-dependent cotranscription of these loci, substantiating the metabolic studies. Biochemical and quantitative real-time (qRT)-PCR studies revealed the presence of two distinct O-demethylases, viz., VerAB and VanAB, involved in the oxidative demethylation of veratric acid and vanillic acid, respectively. This report describes the various steps involved in metabolizing lignin-derived aromatic compounds at the biochemical level and identifies the genes involved in degrading veratric acid and the arrangement of phenylpropanoid metabolic genes as three distinct inducible transcription units/operons. This study provides insight into the bacterial degradation of lignin-derived aromatics and the potential of P. putida CSV86 as a suitable candidate for producing valuable products. IMPORTANCE Pseudomonas putida CSV86 metabolizes lignin and its metabolic intermediates as a carbon source. Strain CSV86 displays a unique property of preferential utilization of aromatics, including for phenylpropanoids over glucose. This report unravels veratryl alcohol metabolism and genes encoding veratric acid O-demethylase, hitherto unknown in pseudomonads, thereby providing new insight into the

  5. 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.

  6. Mechanisms of carbon dioxide acquisition and CO2 sensing in marine diatoms: a gateway to carbon metabolism.

    Science.gov (United States)

    Matsuda, Yusuke; Hopkinson, Brian M; Nakajima, Kensuke; Dupont, Christopher L; Tsuji, Yoshinori

    2017-09-05

    discussed.This article is part of the themed issue 'The peculiar carbon metabolism in diatoms'. © 2017 The Author(s).

  7. Utilization of carbon 13-labelled stable isotopes for studying drug toxicity on cellular metabolism

    International Nuclear Information System (INIS)

    Herve, M.; Wietzerbin, J.; Tran-Dinh, S.

    1994-01-01

    A new approach for studying the effects of two drugs, amphotericine B (AMB), an anti-fungal antibiotic, and 2-deoxy-D-glucose (DG), on the glucose metabolism in brewer yeast cells (Saccharomyces cerevisiae), is presented; AMB interacts with the membrane sterols, inducing formation of pores through which ions and small molecules can pass. DG may enter in the cytosol, where it is phosphoryled by hexokinase into deoxy-D-glucose 6-phosphate (DG6P) which disappears very slowly. DG slows down the glycolysis process and induces the formation of new substances. This paper shows the advantages of utilizing carbon 13-labelled substrates combined to the NMR-13C and NMR-1H techniques. 6 figs., 5 refs

  8. P-Ser-HPr-a link between carbon metabolism and the virulence of some pathogenic bacteria

    DEFF Research Database (Denmark)

    Mijakovic, Ivan

    2005-01-01

    HPr kinase/phosphorylase phosphorylates HPr, a phosphocarrier protein of the phosphoenolpyruvate:carbohydrate phosphotransferase system, at serine-46. P-Ser-HPr is the central regulator of carbon metabolism in Gram-positive bacteria, but also plays a role in virulence development of certain...... pathogens. In Listeria monocytogenes, several virulence genes, which depend on the transcription activator PrfA, are repressed by glucose, fructose, etc., in a catabolite repressor (CcpA)-independent mechanism. However, the catabolite co-repressor P-Ser-HPr was found to inhibit the activity of Prf...... is preceded by an operator site, which serves as target for the CcpA/P-Ser-HPr complex. Numerous Gram-negative pathogens also contain hprK, which is often organised in an operon with transcription regulators necessary for the development of virulence, indicating that in these organisms P-Ser-HPr also plays...

  9. Shell carbon isotope indicators of metabolic activity in the deep-sea mussel Bathymodiolus childressi

    Science.gov (United States)

    Riekenberg, P. M.; Carney, R. S.; Fry, B.

    2018-04-01

    The incorporation of metabolic carbon (Cm) into shells of mollusks has been used as an indicator of animal condition and availability of food resources in estuarine and freshwater settings. This study examines Cm in Bathymodiolus childressi, a marine cold seep mussel dependent on methanotrophic symbionts. As seeps develop, mature, and go quiescent, methane supply will vary and affect the amount of metabolic carbon deposited into the growing shell. B. childressi (n = 136) were live-collected from two seep sites over a 17 year period in the Northern Gulf of Mexico to investigate whether changes in Cm were detectable between sites and across years. Significant differences in Cm were observed between mussel populations at Brine Pool (15.4 ± 0.4%) and Bush Hill (10.3 ± 0.3%). Cm also changed significantly within each site across year (Bush Hill 1991: 12.2 ± 0.5%, 1992: 17.3 ± 0.8%) and decadal time scales (Brine Pool 1989: 15.5 ± 0.7%, 2006: 19.5 ± 0.7%). These findings agree with previous studies that found mussel condition was higher at Brine Pool and correlate well with a trophic mixing model that indicated significantly higher methane source utilization at the Brine Pool (65 ± 1.1%) than at Bush Hill (49 ± 1.6%). Further development of this method should allow for assessment of Cm in shell assemblages as an indicator of historical resource availability at both active and former cold seep sites.

  10. Micronutrients Involved in One-Carbon Metabolism and Risk of Breast Cancer Subtypes.

    Directory of Open Access Journals (Sweden)

    Ilaria Cancarini

    Full Text Available Vitamins involved in one-carbon metabolism are hypothesized to influence breast cancer (BC risk. However, epidemiologic studies that examined associations between B vitamin intake and BC risk have provided inconsistent results. We prospectively examined, in the Italian ORDET cohort, whether B vitamin consumption was associated with risk of BC and BC subtypes.After a mean follow-up of 16.5 years, 391 BCs were diagnosed among 10,786 cohort women. B vitamin intakes were estimated from food frequency questionnaires. Cox proportional hazard models adjusted for energy intake and confounders, estimated hazard ratios (HR with 95% confidence intervals (CIs for BC according to intake.RRs were 0.61 (95% CI 0.38-0.97 highest vs. lowest quartile; P trend 0.025 for thiamine; 0.48 (95% CI 0.32-0.71; P trend <0.001 for riboflavin; 0.59 (95% CI 0.39-0.90; P trend 0.008 for vitamin B6, and 0.65 (95% CI 0.44-0.95; P trend 0.021 for folate. As regards risk of BC subtypes, high riboflavin and folate were significantly associated with lower risk of estrogen receptor positive (ER+ and progesterone receptor positive (PR+ cancers, and high thiamine was associated with lower risk of ER-PR- cancers. High riboflavin was associated with lower risk of both HER2+ and HER2- cancers, high folate with lower risk of HER2- disease, and high thiamine with HER2+ disease.These findings support protective effects of thiamine and one-carbon metabolism vitamins (folate, riboflavin, and vitamin B6 against BC in general; while folate may also protect against ER+PR+ and HER2- disease; and thiamine against ER-PR-, and HER2+ disease.

  11. Clinical utility of polymorphisms in one-carbon metabolism for breast cancer risk prediction

    Directory of Open Access Journals (Sweden)

    Shaik Mohammad Naushad

    2011-01-01

    Full Text Available This study addresses the issues in translating the laboratory derived data obtained during discovery phase of research to a clinical setting using a breast cancer model. Laboratory-based risk assessment indi-cated that a family history of breast cancer, reduced folate carrier 1 (RFC1 G80A, thymidylate synthase (TYMS 5’-UTR 28bp tandem repeat, methylene tetrahydrofolate reductase (MTHFR C677T and catecholamine-O-methyl transferase (COMT genetic polymorphisms in one-carbon metabolic pathway increase the risk for breast cancer. Glutamate carboxypeptidase II (GCPII C1561T and cytosolic serine hydroxymethyl transferase (cSHMT C1420T polymorphisms were found to decrease breast cancer risk. In order to test the clinical validity of this information in the risk prediction of breast cancer, data was stratified based on number of protective alleles into four categories and in each category sensitivity and 1-specificity values were obtained based on the distribution of number of risk alleles in cases and controls. Receiver operating characteristic (ROC curves were plotted and the area under ROC curve (C was used as a measure of discriminatory ability between cases and controls. In subjects without any protective allele, aberrations in one-carbon metabolism showed perfect prediction (C=0.93 while the predictability was lost in subjects with one protective allele (C=0.60. However, predictability increased steadily with increasing number of protective alleles (C=0.63 for 2 protective alleles and C=0.71 for 3 protective alleles. The cut-off point for discrimination was >4 alleles in all predictable combinations. Models of this kind can serve as valuable tools in translational re-search, especially in identifying high-risk individuals and reducing the disease risk either by life style modification or by medical intervention.

  12. 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. © 2016 Wiley Periodicals, Inc.

  13. Zooplankton biomass and metabolism through image analysis systems: from the development and testing of metabolic equations to the assessment of carbon fluxes

    OpenAIRE

    Garijo, Juan Carlos

    2016-01-01

    Programa de Doctorado en Oceanografía Zooplankton plays an important role in the biogeochemical cycles in the ocean. Due to their central position in the ocean’s food web, they recycle and redistribute energy and matter, not only at different levels of the trophic web, but also horizontally and vertically in the water column. Understanding the role of zooplankton in the biological pump and the ocean carbon cycle requires accurate estimates of community biomass and metabolism at large spati...

  14. Metabolic activation of carbon tetrachloride by the cervico-vaginal epithelium in rodents

    International Nuclear Information System (INIS)

    Brittebo, E.B.; Brandt, I.

    1989-01-01

    The metabolism and binding of 14 C-labelled carbon tetrachloride (CCl 4 ) in the genital tract of female adult or juvenile NMRI-mice and Sprague-Dawly rats (mainly in the pro-oestrous/oestrous stage) and an adult New Zealand rabbit were studied. A marked irreversible binding of radioactivity in the squamous cervico-vaginal epithelium of mice given intravenous injections of 14 C-CCl 4 was revealed by autoradiography of solvent-extracted tissue. The localization of binding in the mouse genital tract incubated with 14 C-CCl 4 under air was similar to that observed in vivo. Bound radioactivity was also present in the cylindrical epithelium of the rabbit vagina incubated with 14 C-CCl 4 in vitro. For a comparison, no preferential binding of radiolabelled diethylstilbestrol or ethinylestradiol was observed in the mouse cervico-vaginal epithelium. The level of irreversible binding to PMSG-primed (pregnant mare's serum gonadotrophin) vaginal epithelial 100 x g supernatants of mice and rats incubated with 14 C-CCl 4 under air was low. Addition of the reducing agent dithionite to the incubations increased the binding in the vaginal epithelium 20-fold. In juvenile mice and rats injected with 14 C-CCl 4 , the levels of metabolites in the epithelium were low, whereas PMSG-primed juvenile rats contained a higher level of metabolites. The results show that the cervico-vaginal epithelium can metabolically activate CCl 4 to reactive metabolites and suggest that the metabolism is under endocrine control. (author)

  15. Anaerobic carbon monoxide metabolism by Pleomorphomonas carboxyditropha sp. nov., a new mesophilic hydrogenogenic carboxydotroph.

    Science.gov (United States)

    Esquivel-Elizondo, Sofia; Maldonado, Juan; Krajmalnik-Brown, Rosa

    2018-06-01

    Carbon monoxide (CO)-metabolism and phenotypic and phylogenetic characterization of a novel anaerobic, mesophilic and hydrogenogenic carboxydotroph are reported. Strain SVCO-16 was isolated from anaerobic sludge and grows autotrophically and mixotrophically with CO. The genes cooS and cooF, coding for a CO dehydrogenase complex, and genes similar to hycE2, encoding a CO-induced hydrogenase, were present in its genome. The isolate produces H2 and CO2 from CO, and acetate and formate from organic substrates. Based on the 16S rRNA sequence, it is an Alphaproteobacterium most closely related to the genus Pleomorphomonas (98.9%-99.2% sequence identity). Comparison with other previously characterized Pleomorphomonas showed that P. diazotrophica and P. oryzae do not metabolize CO, and P. diazotrophica does not grow anaerobically with organic substrates. Average nucleotide identity values between strain SVCO-16 and P. diazotrophica, P. oryzae or P. koreensis were 86.66 ± 0.21%. These values are below the boundary to define species (95%-96%). Digital DNA-DNA hybridization estimates between strain SVCO-16 and reference strains were also below the 70% threshold for species delineation: 29.1%-34.5%. Based on the differences in CO metabolism, genome analyses and cellular fatty acid composition, the isolate should be classified into the genus Pleomorphomonas as a representative of a novel species, Pleomorphomonas carboxyditropha. The type strain of Pleomorphomonas carboxyditropha is SVCO-16T (strain deposit numbers, DSM 106132T and TSD-119T).

  16. 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

  17. Transcriptome analysis of temporal regulation of carbon metabolism by CcpA in Bacillus subtilis reveals additional target genes

    NARCIS (Netherlands)

    Lulko, Andrzej T.; Buist, Girbe; Kok, Jan; Kuipers, Oscar P.

    2007-01-01

    The pleiotropic regulator of carbon metabolism in Grampositive bacteria, CcpA, regulates gene expression by binding to so-called cre elements, which are located either upstream or in promoter regions, or in open-reading frames. In this study we compared the transcriptomes of Bacillus subtilis 168

  18. 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

  19. Gene-diet-interactions in folate-mediated one-carbon metabolism modify colon cancer risk.

    Science.gov (United States)

    Liu, Amy Y; Scherer, Dominique; Poole, Elizabeth; Potter, John D; Curtin, Karen; Makar, Karen; Slattery, Martha L; Caan, Bette J; Ulrich, Cornelia M

    2013-04-01

    The importance of folate-mediated one-carbon metabolism (FOCM) in colorectal carcinogenesis is emphasized by observations that high dietary folate intake is associated with decreased risk of colon cancer (CC) and its precursors. Additionally, polymorphisms in FOCM-related genes have been repeatedly associated with risk, supporting a causal relationship between folate and colorectal carcinogenesis. We investigated ten candidate polymorphisms with defined or probable functional impact in eight FOCM-related genes (SHMT1, DHFR, DNMT1, MTHFD1, MTHFR, MTRR, TCN2, and TDG) in 1609 CC cases and 1974 controls for association with CC risk and for interaction with dietary factors. No polymorphism was statistically significantly associated with overall risk of CC. However, statistically significant interactions modifying CC risk were observed for DNMT1 I311V with dietary folate, methionine, vitamin B2 , and vitamin B12 intake and for MTRR I22M with dietary folate, a predefined one-carbon dietary pattern, and vitamin B6 intake. We observed statistically significant gene-diet interactions with five additional polymorphisms. Our results provide evidence that FOCM-related dietary intakes modify the association between CC risk and FOCM allelic variants. These findings add to observations showing that folate-related gene-nutrient interactions play an important role in modifying the risk of CC. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Vision Issues and Space Flight: Evaluation of One-Carbon Metabolism Polymorphisms

    Science.gov (United States)

    Smith, Scott M.; Gregory, Jesse F.; Zeisel, Steven; Ueland, Per; Gibson, C. R.; Mader, Thomas; Kinchen, Jason; Ploutz-Snyder, Robert; Zwart, Sara R.

    2015-01-01

    Intermediates of the one-carbon metabolic pathway are altered in astronauts who experience vision-related issues during and after space flight. Serum concentrations of homocysteine, cystathionine, 2-methylcitric acid, and methylmalonic acid were higher in astronauts with ophthalmic changes than in those without (Zwart et al., J Nutr, 2012). These differences existed before, during, and after flight. Potential confounding factors did not explain the differences. Genetic polymorphisms could contribute to these differences, and could help explain why crewmembers on the same mission do not all have ophthalmic issues, despite the same environmental factors (e.g., microgravity, exercise, diet). A follow-up study was conducted to evaluate 5 polymorphisms of enzymes in the one-carbon pathway, and to evaluate how these relate to vision and other ophthalmic changes after flight. Preliminary evaluations of the genetic data indicate that all of the crewmembers with the MTRR GG genotype had vision issues to one degree or another. However, not everyone who had vision issues had this genetic polymorphism, so the situation is more complex than the involvement of this single polymorphism. Metabolomic and further data analyses are underway to clarify these findings, but the preliminary assessments are promising.

  1. Metabolic engineering of Corynebacterium glutamicum aimed at alternative carbon sources and new products

    Directory of Open Access Journals (Sweden)

    Volker Fritz Wendisch

    2012-10-01

    Full Text Available Corynebacterium glutamicum is well known as the amino acid-producing workhorse of fermentation industry, being used for multi-million-ton scale production of glutamate and lysine for more than 60 years. However, it is only recently that extensive research has focused on engineering it beyond the scope of amino acids. Meanwhile, a variety of corynebacterial strains allows access to alternative carbon sources and/or allows production of a wide range of industrially relevant compounds. Some of these efforts set new standards in terms of titers and productivities achieved whereas others represent a proof-of-principle. These achievements manifest the position of C. glutamicum as an important industrial microorganism with capabilities far beyond the traditional amino acid production. In this review we focus on the state of the art of metabolic engineering of C. glutamicum for utilization of alternative carbon sources, (e.g. coming from wastes and unprocessed sources, and construction of C. glutamicum strains for production of new products such as diamines, organic acids and alcohols.

  2. Contrasting Inherent Optical Properties and Carbon Metabolism Between Five Northeastern (USA) Estuary-plume Systems

    Science.gov (United States)

    Vandemark, Doug; Salisbury, Joe; Hunt, Chris; McGillis, Wade R.

    2004-01-01

    We have recently developed the ability to rapidly assess Surface inherent optical properties (IOP), oxygen concentration and pCO2 in estuarine-plume systems using flow-through instrumentation. During the summer of 2004, several estuarine-plume systems were surveyed which include the Pleasant (ME), Penobscot (ME), Kennebec-Androscoggin (ME), Merrimack (NH-MA) and Hudson (NY). Continuous measurements of surface chlorophyll and colored dissolved organic carbon (CDOM) fluorescence, beam attenuation, temperature, salinity, oxygen and pC02 were taken at each system along a salinity gradient from fresh water to near oceanic endmembers. CTD and IOP profiles were also taken at predetermined surface salinity intervals. These were accompanied by discrete determinations of chlorophyll (HPLC and fluorometric), total suspended solids (TSS), dissolved organic carbon (DOC) and alkalinity. IOP data were calibrated using chlorophyll, DOC and TSS data to enable the retrieval of these constituents from IOP data. Considerable differences in the data sets were observed between systems. These ranged from the DOC-enriched, strongly heterotrophic Pleasant River System to the high-chlorophyll autotrophic Merrimack River System. Using pCO2 and oxygen saturation measurements as proxies for water column metabolism, distinct relationships were found between trophic status and inherent optical properties. The nature of these relationships varies between systems and is likely a function of watershed and estuarine attributes including carbon and nutrient loading, in-situ production and related autochthonous inputs of DOC and alkalinity. Our results suggest that IOP data may contain significant information about the trophic status of estuarine and plume systems.

  3. Integrating tracer-based metabolomics data and metabolic fluxes in a linear fashion via Elementary Carbon Modes.

    Science.gov (United States)

    Pey, Jon; Rubio, Angel; Theodoropoulos, Constantinos; Cascante, Marta; Planes, Francisco J

    2012-07-01

    Constraints-based modeling is an emergent area in Systems Biology that includes an increasing set of methods for the analysis of metabolic networks. In order to refine its predictions, the development of novel methods integrating high-throughput experimental data is currently a key challenge in the field. In this paper, we present a novel set of constraints that integrate tracer-based metabolomics data from Isotope Labeling Experiments and metabolic fluxes in a linear fashion. These constraints are based on Elementary Carbon Modes (ECMs), a recently developed concept that generalizes Elementary Flux Modes at the carbon level. To illustrate the effect of our ECMs-based constraints, a Flux Variability Analysis approach was applied to a previously published metabolic network involving the main pathways in the metabolism of glucose. The addition of our ECMs-based constraints substantially reduced the under-determination resulting from a standard application of Flux Variability Analysis, which shows a clear progress over the state of the art. In addition, our approach is adjusted to deal with combinatorial explosion of ECMs in genome-scale metabolic networks. This extension was applied to infer the maximum biosynthetic capacity of non-essential amino acids in human metabolism. Finally, as linearity is the hallmark of our approach, its importance is discussed at a methodological, computational and theoretical level and illustrated with a practical application in the field of Isotope Labeling Experiments. Copyright © 2012 Elsevier Inc. All rights reserved.

  4. DRUM: a new framework for metabolic modeling under non-balanced growth. Application to the carbon metabolism of unicellular microalgae.

    Science.gov (United States)

    Baroukh, Caroline; Muñoz-Tamayo, Rafael; Steyer, Jean-Philippe; Bernard, Olivier

    2014-01-01

    Metabolic modeling is a powerful tool to understand, predict and optimize bioprocesses, particularly when they imply intracellular molecules of interest. Unfortunately, the use of metabolic models for time varying metabolic fluxes is hampered by the lack of experimental data required to define and calibrate the kinetic reaction rates of the metabolic pathways. For this reason, metabolic models are often used under the balanced growth hypothesis. However, for some processes such as the photoautotrophic metabolism of microalgae, the balanced-growth assumption appears to be unreasonable because of the synchronization of their circadian cycle on the daily light. Yet, understanding microalgae metabolism is necessary to optimize the production yield of bioprocesses based on this microorganism, as for example production of third-generation biofuels. In this paper, we propose DRUM, a new dynamic metabolic modeling framework that handles the non-balanced growth condition and hence accumulation of intracellular metabolites. The first stage of the approach consists in splitting the metabolic network into sub-networks describing reactions which are spatially close, and which are assumed to satisfy balanced growth condition. The left metabolites interconnecting the sub-networks behave dynamically. Then, thanks to Elementary Flux Mode analysis, each sub-network is reduced to macroscopic reactions, for which simple kinetics are assumed. Finally, an Ordinary Differential Equation system is obtained to describe substrate consumption, biomass production, products excretion and accumulation of some internal metabolites. DRUM was applied to the accumulation of lipids and carbohydrates of the microalgae Tisochrysis lutea under day/night cycles. The resulting model describes accurately experimental data obtained in day/night conditions. It efficiently predicts the accumulation and consumption of lipids and carbohydrates.

  5. DRUM: a new framework for metabolic modeling under non-balanced growth. Application to the carbon metabolism of unicellular microalgae.

    Directory of Open Access Journals (Sweden)

    Caroline Baroukh

    Full Text Available Metabolic modeling is a powerful tool to understand, predict and optimize bioprocesses, particularly when they imply intracellular molecules of interest. Unfortunately, the use of metabolic models for time varying metabolic fluxes is hampered by the lack of experimental data required to define and calibrate the kinetic reaction rates of the metabolic pathways. For this reason, metabolic models are often used under the balanced growth hypothesis. However, for some processes such as the photoautotrophic metabolism of microalgae, the balanced-growth assumption appears to be unreasonable because of the synchronization of their circadian cycle on the daily light. Yet, understanding microalgae metabolism is necessary to optimize the production yield of bioprocesses based on this microorganism, as for example production of third-generation biofuels. In this paper, we propose DRUM, a new dynamic metabolic modeling framework that handles the non-balanced growth condition and hence accumulation of intracellular metabolites. The first stage of the approach consists in splitting the metabolic network into sub-networks describing reactions which are spatially close, and which are assumed to satisfy balanced growth condition. The left metabolites interconnecting the sub-networks behave dynamically. Then, thanks to Elementary Flux Mode analysis, each sub-network is reduced to macroscopic reactions, for which simple kinetics are assumed. Finally, an Ordinary Differential Equation system is obtained to describe substrate consumption, biomass production, products excretion and accumulation of some internal metabolites. DRUM was applied to the accumulation of lipids and carbohydrates of the microalgae Tisochrysis lutea under day/night cycles. The resulting model describes accurately experimental data obtained in day/night conditions. It efficiently predicts the accumulation and consumption of lipids and carbohydrates.

  6. 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.

  7. 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.

  8. Reprogramming One-Carbon Metabolic Pathways To Decouple l-Serine Catabolism from Cell Growth in Corynebacterium glutamicum.

    Science.gov (United States)

    Zhang, Yun; Shang, Xiuling; Lai, Shujuan; Zhang, Yu; Hu, Qitiao; Chai, Xin; Wang, Bo; Liu, Shuwen; Wen, Tingyi

    2018-02-16

    l-Serine, the principal one-carbon source for DNA biosynthesis, is difficult for microorganisms to accumulate due to the coupling of l-serine catabolism and microbial growth. Here, we reprogrammed the one-carbon unit metabolic pathways in Corynebacterium glutamicum to decouple l-serine catabolism from cell growth. In silico model-based simulation showed a negative influence on glyA-encoding serine hydroxymethyltransferase flux with l-serine productivity. Attenuation of glyA transcription resulted in increased l-serine accumulation, and a decrease in purine pools, poor growth and longer cell shapes. The gcvTHP-encoded glycine cleavage (Gcv) system from Escherichia coli was introduced into C. glutamicum, allowing glycine-derived 13 CH 2 to be assimilated into intracellular purine synthesis, which resulted in an increased amount of one-carbon units. Gcv introduction not only restored cell viability and morphology but also increased l-serine accumulation. Moreover, comparative proteomic analysis indicated that abundance changes of the enzymes involved in one-carbon unit cycles might be responsible for maintaining one-carbon unit homeostasis. Reprogramming of the one-carbon metabolic pathways allowed cells to reach a comparable growth rate to accumulate 13.21 g/L l-serine by fed-batch fermentation in minimal medium. This novel strategy provides new insights into the regulation of cellular properties and essential metabolite accumulation by introducing an extrinsic pathway.

  9. Radio-metabolite analysis of carbon-11 biochemical partitioning to non-structural carbohydrates for integrated metabolism and transport studies.

    Science.gov (United States)

    Babst, Benjamin A; Karve, Abhijit A; Judt, Tatjana

    2013-06-01

    Metabolism and phloem transport of carbohydrates are interactive processes, yet each is often studied in isolation from the other. Carbon-11 ((11)C) has been successfully used to study transport and allocation processes dynamically over time. There is a need for techniques to determine metabolic partitioning of newly fixed carbon that are compatible with existing non-invasive (11)C-based methodologies for the study of phloem transport. In this report, we present methods using (11)C-labeled CO2 to trace carbon partitioning to the major non-structural carbohydrates in leaves-sucrose, glucose, fructose and starch. High-performance thin-layer chromatography (HPTLC) was adapted to provide multisample throughput, raising the possibility of measuring different tissues of the same individual plant, or for screening multiple plants. An additional advantage of HPTLC was that phosphor plate imaging of radioactivity had a much higher sensitivity and broader range of sensitivity than radio-HPLC detection, allowing measurement of (11)C partitioning to starch, which was previously not possible. Because of the high specific activity of (11)C and high sensitivity of detection, our method may have additional applications in the study of rapid metabolic responses to environmental changes that occur on a time scale of minutes. The use of this method in tandem with other (11)C assays for transport dynamics and whole-plant partitioning makes a powerful combination of tools to study carbohydrate metabolism and whole-plant transport as integrated processes.

  10. Long-term monitoring reveals carbon-nitrogen metabolism key to microcystin production in eutrophic lakes

    Directory of Open Access Journals (Sweden)

    Lucas J Beversdorf

    2015-05-01

    Full Text Available The environmental drivers contributing to cyanobacterial dominance in aquatic systems have been extensively studied. However, understanding of toxic versus non-toxic cyanobacterial population dynamics and the mechanisms regulating cyanotoxin production remain elusive, both physiologically and ecologically. One reason is the disconnect between laboratory and field-based studies. Here, we combined three years of temporal data, including microcystin (MC concentrations, 16 years of long-term ecological research, and 10 years of molecular data to investigate the potential factors leading to the selection of toxic Microcystis and MC production. Our analysis revealed that nitrogen (N speciation and inorganic carbon (C availability might be important drivers of Microcystis population dynamics and that an imbalance in cellular C: N ratios may trigger MC production. More specifically, precipitous declines in ammonium concentrations lead to a transitional period of N stress, even in the presence of high nitrate concentrations, that we call the toxic phase. Following the toxic phase, temperature and cyanobacterial abundance remained elevated but MC concentrations drastically declined. Increases in ammonium due to lake turnover may have led to down regulation of MC synthesis or a shift in the community from toxic to non-toxic species. While total phosphorus (P to total N ratios were relatively low over the time-series, MC concentrations were highest when total N to total P ratios were also highest. Similarly, high C: N ratios were also strongly correlated to the toxic phase. We propose a metabolic model that corroborates molecular studies and reflects our ecological observations that C and N metabolism may regulate MC production physiologically and ecologically. In particular, we hypothesize that an imbalance between 2-oxoglutarate and ammonium in the cell regulates MC synthesis in the environment.

  11. Metabolism and disposition of ethylene carbonate in male Fischer 344 rats

    International Nuclear Information System (INIS)

    Hanley, T.R. Jr.; Schumann, A.M.; Langvardt, P.W.; Rusek, T.F.; Watanabe, P.G.

    1989-01-01

    Ethylene carbonate (EC) has a toxicity profile which resembles that of ethylene glycol (EG). To determine whether the toxicity of EC could be explained on the basis of its metabolism to EG, male Fischer 344 rats were given 200 mg/kg of uniformly labeled [ 14 C]EC in water by gavage and the disposition of the radiolabel was then followed for 72 hr. EC was rapidly metabolized, with approximately 57 and 27% of the administered dose eliminated in the expired air as 14CO2 and in the urine, respectively; the remainder was found in the carcass. Separation of the urinary metabolites using liquid chromatography revealed a single radioactive peak. This metabolite was unequivocally identified as ethylene glycol via gas chromatography-mass spectrometry with the aid of 13C enrichment of the EC dose. Measurement of whole blood levels of EC and EG in rats given 200 mg/kg of EC by gavage revealed blood levels of EG approximately 100-fold higher than the levels of EC in these same animals, with a half-life of EG in blood of 2 hr, indicating rapid conversion of EC to EG. In a separate group of animals administered an equimolar dose of [ 14 C]EG (141 mg/kg), approximately 37% of the dose was expired as 14 CO 2 and 42% was excreted in the urine as parent compound. When expressed on the basis of the ethanediol moiety, the disposition of EC was identical to that of EG. In view of the rapid and extensive biotransformation of EC to EG and the similarity of the existing (though limited) toxicity data base of EC compared to EG, utilization of the extensive EG systemic toxicity data base for assessing the safety of EC appears justified

  12. Choline and methionine differentially alter methyl carbon metabolism in bovine neonatal hepatocytes.

    Science.gov (United States)

    Chandler, Tawny L; White, Heather M

    2017-01-01

    Intersections in hepatic methyl group metabolism pathways highlights potential competition or compensation of methyl donors. The objective of this experiment was to examine the expression of genes related to methyl group transfer and lipid metabolism in response to increasing concentrations of choline chloride (CC) and DL-methionine (DLM) in primary neonatal hepatocytes that were or were not exposed to fatty acids (FA). Primary hepatocytes isolated from 4 neonatal Holstein calves were maintained as monolayer cultures for 24 h before treatment with CC (61, 128, 2028, and 4528 μmol/L) and DLM (16, 30, 100, 300 μmol/L), with or without a 1 mmol/L FA cocktail in a factorial arrangement. After 24 h of treatment, media was collected for quantification of reactive oxygen species (ROS) and very low-density lipoprotein (VLDL), and cell lysates were collected for quantification of gene expression. No interactions were detected between CC, DLM, or FA. Both CC and DLM decreased the expression of methionine adenosyltransferase 1A (MAT1A). Increasing CC did not alter betaine-homocysteine S-methyltranferase (BHMT) but did increase 5-methyltetrahydrofolate-homocysteine methyltransferase (MTR) and methylenetetrahydrofolate reductase (MTHFR) expression. Increasing DLM decreased expression of BHMT and MTR, but did not affect MTHFR. Expression of both phosphatidylethanolamine N-methyltransferase (PEMT) and microsomal triglyceride transfer protein (MTTP) were decreased by increasing CC and DLM, while carnitine palmitoyltransferase 1A (CPT1A) was unaffected by either. Treatment with FA decreased the expression of MAT1A, MTR, MTHFR and tended to decrease PEMT but did not affect BHMT and MTTP. Treatment with FA increased CPT1A expression. Increasing CC increased secretion of VLDL and decreased the accumulation of ROS in media. Within neonatal bovine hepatocytes, choline and methionine differentially regulate methyl carbon pathways and suggest that choline may play a critical role in

  13. Investigation of the microbial metabolism of carbon dioxide and hydrogen in the kangaroo foregut by stable isotope probing.

    Science.gov (United States)

    Godwin, Scott; Kang, Alicia; Gulino, Lisa-Maree; Manefield, Mike; Gutierrez-Zamora, Maria-Luisa; Kienzle, Marco; Ouwerkerk, Diane; Dawson, Kerri; Klieve, Athol V

    2014-09-01

    Kangaroos ferment forage material in an enlarged forestomach analogous to the rumen, but in contrast to ruminants, they produce little or no methane. The objective of this study was to identify the dominant organisms and pathways involved in hydrogenotrophy in the kangaroo forestomach, with the broader aim of understanding how these processes are able to predominate over methanogenesis. Stable isotope analysis of fermentation end products and RNA stable isotope probing (RNA-SIP) were used to investigate the organisms and biochemical pathways involved in the metabolism of hydrogen and carbon dioxide in the kangaroo forestomach. Our results clearly demonstrate that the activity of bacterial reductive acetogens is a key factor in the reduced methane output of kangaroos. In in vitro fermentations, the microbial community of the kangaroo foregut produced very little methane, but produced a significantly greater proportion of acetate derived from carbon dioxide than the microbial community of the bovine rumen. A bacterial operational taxonomic unit closely related to the known reductive acetogen Blautia coccoides was found to be associated with carbon dioxide and hydrogen metabolism in the kangaroo foregut. Other bacterial taxa including members of the genera Prevotella, Oscillibacter and Streptococcus that have not previously been reported as containing hydrogenotrophic organisms were also significantly associated with metabolism of hydrogen and carbon dioxide in the kangaroo forestomach.

  14. Dynamic Labeling Reveals Temporal Changes in Carbon Re-Allocation within the Central Metabolism of Developing Apple Fruit

    Directory of Open Access Journals (Sweden)

    Wasiye F. Beshir

    2017-10-01

    Full Text Available In recent years, the application of isotopically labeled substrates has received extensive attention in plant physiology. Measuring the propagation of the label through metabolic networks may provide information on carbon allocation in sink fruit during fruit development. In this research, gas chromatography coupled to mass spectrometry based metabolite profiling was used to characterize the changing metabolic pool sizes in developing apple fruit at five growth stages (30, 58, 93, 121, and 149 days after full bloom using 13C-isotope feeding experiments on hypanthium tissue discs. Following the feeding of [U-13C]glucose, the 13C-label was incorporated into the various metabolites to different degrees depending on incubation time, metabolic pathway activity, and growth stage. Evidence is presented that early in fruit development the utilization of the imported sugars was faster than in later developmental stages, likely to supply the energy and carbon skeletons required for cell division and fruit growth. The declined 13C-incorporation into various metabolites during growth and maturation can be associated with the reduced metabolic activity, as mirrored by the respiratory rate. Moreover, the concentration of fructose and sucrose increased during fruit development, whereas concentrations of most amino and organic acids and polyphenols declined. In general, this study showed that the imported compounds play a central role not only in carbohydrate metabolism, but also in the biosynthesis of amino acid and related protein synthesis and secondary metabolites at the early stage of fruit development.

  15. 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.

  16. 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.

  17. The Essential Role of Cholesterol Metabolism in the Intracellular Survival of Mycobacterium leprae Is Not Coupled to Central Carbon Metabolism and Energy Production.

    Science.gov (United States)

    Marques, Maria Angela M; Berrêdo-Pinho, Marcia; Rosa, Thabatta L S A; Pujari, Venugopal; Lemes, Robertha M R; Lery, Leticia M S; Silva, Carlos Adriano M; Guimarães, Ana Carolina R; Atella, Georgia C; Wheat, William H; Brennan, Patrick J; Crick, Dean C; Belisle, John T; Pessolani, Maria Cristina V

    2015-12-01

    Mycobacterium leprae induces the formation of lipid droplets, which are recruited to pathogen-containing phagosomes in infected macrophages and Schwann cells. Cholesterol is among the lipids with increased abundance in M. leprae-infected cells, and intracellular survival relies on cholesterol accumulation. The present study investigated the capacity of M. leprae to acquire and metabolize cholesterol. In silico analyses showed that oxidation of cholesterol to cholest-4-en-3-one (cholestenone), the first step of cholesterol degradation catalyzed by the enzyme 3β-hydroxysteroid dehydrogenase (3β-HSD), is apparently the only portion of the cholesterol catabolic pathway seen in Mycobacterium tuberculosis preserved by M. leprae. Incubation of bacteria with radiolabeled cholesterol confirmed the in silico predictions. Radiorespirometry and lipid analyses performed after incubating M. leprae with [4-(14)C]cholesterol or [26-(14)C]cholesterol showed the inability of this pathogen to metabolize the sterol rings or the side chain of cholesterol as a source of energy and carbon. However, the bacteria avidly incorporated cholesterol and, as expected, converted it to cholestenone both in vitro and in vivo. Our data indicate that M. leprae has lost the capacity to degrade and utilize cholesterol as a nutritional source but retains the enzyme responsible for its oxidation to cholestenone. Thus, the essential role of cholesterol metabolism in the intracellular survival of M. leprae is uncoupled from central carbon metabolism and energy production. Further elucidation of cholesterol metabolism in the host cell during M. leprae infection will establish the mechanism by which this lipid supports M. leprae intracellular survival and will open new avenues for novel leprosy therapies. Our study focused on the obligate intracellular pathogen Mycobacterium leprae and its capacity to metabolize cholesterol. The data make an important contribution for those interested in understanding the

  18. One carbon metabolism in anaerobic bacteria: Regulation of carbon and electron flow during organic acid production: Progress report, February 1, 1987-February 1, 1988

    International Nuclear Information System (INIS)

    Zeikus, J.G.; Shen, Gwo-Jenn.

    1988-01-01

    These studies concern the fundamental biochemical mechanisms that control carbon and electron flow in anaerobic bacteria that conserve energy when coupling hydrogen consumption to the production of acetic, propionic, or butyric acids. Two acidogens, Propionispira arboris and Butyribacterium methylotrophicum were chosen as model systems to understand the function of oxidoreductases and electron carriers in the regulation of hydrogen metabolism and single carbon metabolism. In P. arboris, H 2 consumption was linked to the inhibition of CO 2 production and an increase in the propionate/acetate rate; whereas, H 2 consumption was linked to a stimulation of CO 2 consumption and an increase in the butyrate/acetate ratio in B. methylotrophicum. We report studies on the enzymes involved in the regulation of singe carbon metabolism, the enzyme activities and pathways responsible for conversion of multicarbon components to acetate and propionate or butyrate, and how low pH inhibits H 2 and acetic acid production in Sarcina ventriculi as a consequence of hydrogenase regulation. 9 refs

  19. 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.

  20. Microarray and bioinformatic analyses suggest models for carbon metabolism in the autotroph Acidithiobacillus ferrooxidans

    Energy Technology Data Exchange (ETDEWEB)

    C. Appia-ayme; R. Quatrini; Y. Denis; F. Denizot; S. Silver; F. Roberto; F. Veloso; J. Valdes; J. P. Cardenas; M. Esparza; O. Orellana; E. Jedlicki; V. Bonnefoy; D. Holmes

    2006-09-01

    Acidithiobacillus ferrooxidans is a chemolithoautotrophic bacterium that uses iron or sulfur as an energy and electron source. Bioinformatic analysis was used to identify putative genes and potential metabolic pathways involved in CO2 fixation, 2P-glycolate detoxification, carboxysome formation and glycogen utilization in At. ferrooxidans. Microarray transcript profiling was carried out to compare the relative expression of the predicted genes of these pathways when the microorganism was grown in the presence of iron versus sulfur. Several gene expression patterns were confirmed by real-time PCR. Genes for each of the above predicted pathways were found to be organized into discrete clusters. Clusters exhibited differential gene expression depending on the presence of iron or sulfur in the medium. Concordance of gene expression within each cluster, suggested that they are operons Most notably, clusters of genes predicted to be involved in CO2 fixation, carboxysome formation, 2P-glycolate detoxification and glycogen biosynthesis were up-regulated in sulfur medium, whereas genes involved in glycogen utilization were preferentially expressed in iron medium. These results can be explained in terms of models of gene regulation that suggest how A. ferrooxidans can adjust its central carbon management to respond to changing environmental conditions.

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

    Directory of Open Access Journals (Sweden)

    Jerzy W. Poskuta

    2014-01-01

    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.

  2. The depressed central carbon and energy metabolisms is associated to the acquisition of levofloxacin resistance in Vibrio alginolyticus.

    Science.gov (United States)

    Cheng, Zhi-Xue; Yang, Man-Jun; Peng, Bo; Peng, Xuan-Xian; Lin, Xiang-Min; Li, Hui

    2018-06-15

    The overuse and misuse of antibiotics lead to bacterial antibiotic resistance, challenging human health and intensive cultivation. It is especially required to understand for the mechanism of antibiotic resistance to control antibiotic-resistant pathogens. The present study characterized the differential proteome of levofloxacin-resistant Vibrio alginolyticus with the most advanced iTRAQ quantitative proteomics technology. A total of 160 proteins of differential abundance were identified, where 70 were decreased and 90 were increased. Further analysis demonstrated that crucial metabolic pathways like TCA cycle were significantly down-regulated. qRT-PCR analysis demonstrated the decreased gene expression of glycolysis/gluconeogenesis, the TCA cycle, and fatty acid biosynthesis. Moreover, Na(+)-NQR complex gene expression, membrane potential and the adenylate energy charge ratio were decreased, indicating that the decreased central carbon metabolism is associated to the acquisition of levofloxacin resistance. Therefore, the reduced central carbon and energy metabolisms form a characteristic feature as fitness costs of V. alginolyticus in resistance to levofloxacin. The overuse and misuse of antibiotics lead to bacterial antibiotic resistance, challenging human health and intensive cultivation. Understanding for the antibiotic resistance mechanisms is especially required to control these antibiotic-resistant pathogens. The present study characterized the differential proteome of levofloxacin-resistant Vibrio alginolyticus using the most advanced iTRAQ quantitative proteomics technology. A total of 160 differential abundance of proteins were identified with 70 decreases and 90 increases by liquid chromatography matrix assisted laser desorption ionization mass spectrometry. Most interestingly, crucial metabolic pathways such as the TCA cycle sharply fluctuated. This is the first report that the reduced central carbon and energy metabolisms form a characteristic feature

  3. 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.

  4. Carbon monoxide is not responsible for the cigarette smokeinduced changes in the pulmonary metabolism of arachidonic acid and prostaglandin E2

    International Nuclear Information System (INIS)

    Maennistoe, J.; Puustinen, T.; Uotila, P.

    1985-01-01

    Cigarette smoke is known to interfere with the pulmonary metabolism of arachidomic acid and prostaglandin E 2 (PGE 2 ). We investigated the possible role of carbon monoxide in these cigarette smoke-infuced alterations. 4 C-Arachidonic acid (50 nmol) was indused into the pulmonary circulation of isolated perfused hamster lungs and the radioactive metabolites in the perfusion effluent, as well as the distribution of incorporated radioactive arachidonic acid within the lung lipids, were analysed. Carbon monoxide, added into the ventilatory air, had no effect on the oxidative metabolism of arachidonic acid or on the distribution of radioactive arachidonic acid within the lung. In addition, carbon monoxide had no effect on the metabolism of PGE 2 following infusion of 100 nmol of 14 C-PGE 2 into the rat pulmonary circulation. The present study suggests that carbon monoxide is not responsible for the cigarette smoke-induced changes in the pulmonary metabolism of arachidonic acid and PGE 2 . (author)

  5. An alternate metabolic hypothesis for a binary mixture of trichloroethylene and carbon tetrachloride: application of physiologically based pharmacokinetic (PBPK) modeling in rats.

    Science.gov (United States)

    Carbon tetrachloride (CC4) and trichloroethylene (TCE) are hepatotoxic volatile organic compounds (VOCs) and environmental contaminants. Previous physiologically based pharmacokinetic (PBPK) models describe the kinetics ofindividual chemical disposition and metabolic clearance fo...

  6. Unveiling DNA structural properties of promoter regions of ...

    Indian Academy of Sciences (India)

    Aditya Kumar

    Unveiling DNA structural properties of promoter regions of prokaryotic transcriptome and their role in gene expression. Aditya Kumar. Assistant Professor. Molecular Biology & Biotechnology. Tezpur University. Tezpur – 784028, Assam ...

  7. Low oxygen affects photophysiology and the level of expression of two-carbon metabolism genes in the seagrass Zostera muelleri.

    Science.gov (United States)

    Kim, Mikael; Brodersen, Kasper Elgetti; Szabó, Milán; Larkum, Anthony W D; Raven, John A; Ralph, Peter J; Pernice, Mathieu

    2018-05-01

    Seagrasses are a diverse group of angiosperms that evolved to live in shallow coastal waters, an environment regularly subjected to changes in oxygen, carbon dioxide and irradiance. Zostera muelleri is the dominant species in south-eastern Australia, and is critical for healthy coastal ecosystems. Despite its ecological importance, little is known about the pathways of carbon fixation in Z. muelleri and their regulation in response to environmental changes. In this study, the response of Z. muelleri exposed to control and very low oxygen conditions was investigated by using (i) oxygen microsensors combined with a custom-made flow chamber to measure changes in photosynthesis and respiration, and (ii) reverse transcription quantitative real-time PCR to measure changes in expression levels of key genes involved in C 4 metabolism. We found that very low levels of oxygen (i) altered the photophysiology of Z. muelleri, a characteristic of C 3 mechanism of carbon assimilation, and (ii) decreased the expression levels of phosphoenolpyruvate carboxylase and carbonic anhydrase. These molecular-physiological results suggest that regulation of the photophysiology of Z. muelleri might involve a close integration between the C 3 and C 4 , or other CO 2 concentrating mechanisms metabolic pathways. Overall, this study highlights that the photophysiological response of Z. muelleri to changing oxygen in water is capable of rapid acclimation and the dynamic modulation of pathways should be considered when assessing seagrass primary production.

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

    Directory of Open Access Journals (Sweden)

    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

  9. Effect of Temperature on Precipitation Rate of Calcium Carbonate Produced through Microbial Metabolic Process of Bio Materials

    Directory of Open Access Journals (Sweden)

    Prima Yane Putri

    2016-09-01

    Full Text Available Concrete is the most widely used construction material in civil engineering. But plain concrete is a brittle material and has little resistance to cracking. The cracking in concrete promotes deterioration such as the corrosion of reinforcing rebar, therefore, repair in filling the crack is often carried out. Recently, repair methods using bio-based materials associated with microbial metabolic processes leading to precipitation of calcium carbonate have been intensively studied. In this study, influencing factors on the precipitation rate depending on the constituents of bio-based material comprising yeast, glucose and calcium acetate mixed in tris buffer solution was examined for improving the rate of initial reactions. In addition, effect of temperature change on the amount of calcium carbonate precipitation was also investigated. The precipitates were identified by X-ray diffraction. It was shown that the increase of temperature lead to a change on calcium carbonate precipitation and caused the pH decrease under 7.0.

  10. Metabolism of carbon-14 labelled l-tryptophan, l-kynerenine and hydroxy-l-kynerenine in miners with scleroderma

    International Nuclear Information System (INIS)

    Hankes, L.V.; De Bruin, E.; Jansen, C.R.; Voster, L.; Schmaeler, M.

    1977-01-01

    Six South African white miners were studied with the 2-g l-tryptophan load test and tracer doses of L-tryptophan-7a-carbon-14, L-kynurenine-keto-carbon-14 and hydroxy-L-kynerenine-keto-carbon-14. The breath 14 CO 2 and 14 urinary metabolites were measured. When they were compared with a previous study of American women with scleroderma, similar 14 CO 2 and tryptophan metabolite excretion patterns were observed in the data from the miners. The labelled quinolinic acid excretion was more significantly elevated in the South African miners' urine than in the urine of the American women. The data from both studies suggest that some patients with scleroderma have an altered step in the tryptophan metabolic pathway after hydroxy-anthranilic acid. What relationship exists between the induction of pulmonary silicosis and the subsequent development of scleroderma, requires additional human studies

  11. Metabolic differentiation in biofilms as indicated by carbon dioxide production rates.

    Science.gov (United States)

    Bester, Elanna; Kroukamp, Otini; Wolfaardt, Gideon M; Boonzaaier, Leandro; Liss, Steven N

    2010-02-01

    The measurement of carbon dioxide production rates as an indication of metabolic activity was applied to study biofilm development and response of Pseudomonas sp. biofilms to an environmental disturbance in the form of a moving air-liquid interface (i.e., shear). A differential response in biofilm cohesiveness was observed after bubble perturbation, and the biofilm layers were operationally defined as either shear-susceptible or non-shear-susceptible. Confocal laser scanning microscopy and image analysis showed a significant reduction in biofilm thickness and biomass after the removal of the shear-susceptible biofilm layer, as well as notable changes in the roughness coefficient and surface-to-biovolume ratio. These changes were accompanied by a 72% reduction of whole-biofilm CO2 production; however, the non-shear-susceptible region of the biofilm responded rapidly after the removal of the overlying cells and extracellular polymeric substances (EPS) along with the associated changes in nutrient and O2 flux, with CO2 production rates returning to preperturbation levels within 24 h. The adaptable nature and the ability of bacteria to respond to environmental conditions were further demonstrated by the outer shear-susceptible region of the biofilm; the average CO2 production rate of cells from this region increased within 0.25 h from 9.45 +/- 5.40 fmol of CO2 x cell(-1) x h(-1) to 22.6 +/- 7.58 fmol of CO2 x cell(-1) x h(-1) when cells were removed from the biofilm and maintained in suspension without an additional nutrient supply. These results also demonstrate the need for sufficient monitoring of biofilm recovery at the solid substratum if mechanical methods are used for biofouling control.

  12. A simple method for measuring fungal metabolic quotient and comparing carbon use efficiency of different isolates: Application to Mediterranean leaf litter fungi

    NARCIS (Netherlands)

    Pinzari, F.; Maggi, O.; Lunghini, D.; Di Lonardo, Paolo; Persiani, A. M.

    2017-01-01

    AbstractThe metabolic efficiency of different microbial groups in carbon source uses and single species storage efficiency is poorly characterised and not adequately represented in most biogeochemical models. It is proposed here a simple approach for an estimation of the metabolic quotient of fungal

  13. Enhanced photosynthetic capacity increases nitrogen metabolism through the coordinated regulation of carbon and nitrogen assimilation in Arabidopsis thaliana.

    Science.gov (United States)

    Otori, Kumi; Tanabe, Noriaki; Maruyama, Toshiki; Sato, Shigeru; Yanagisawa, Shuichi; Tamoi, Masahiro; Shigeoka, Shigeru

    2017-09-01

    Plant growth and productivity depend on interactions between the metabolism of carbon and nitrogen. The sensing ability of internal carbon and nitrogen metabolites (the C/N balance) enables plants to regulate metabolism and development. In order to investigate the effects of an enhanced photosynthetic capacity on the metabolism of carbon and nitrogen in photosynthetically active tissus (source leaves), we herein generated transgenic Arabidopsis thaliana plants (ApFS) that expressed cyanobacterial fructose-1,6-/sedoheptulose-1,7-bisphosphatase in their chloroplasts. The phenotype of ApFS plants was indistinguishable from that of wild-type plants at the immature stage. However, as plants matured, the growth of ApFS plants was superior to that of wild-type plants. Starch levels were higher in ApFS plants than in wild-type plants at 2 and 5 weeks. Sucrose levels were also higher in ApFS plants than in wild-type plants, but only at 5 weeks. On the other hand, the contents of various free amino acids were lower in ApFS plants than in wild-type plants at 2 weeks, but were similar at 5 weeks. The total C/N ratio was the same in ApFS plants and wild-type plants, whereas nitrite levels increased in parallel with elevations in nitrate reductase activity at 5 weeks in ApFS plants. These results suggest that increases in the contents of photosynthetic intermediates at the early growth stage caused a temporary imbalance in the free-C/free-N ratio and, thus, the feedback inhibition of the expression of genes involved in the Calvin cycle and induction of the expression of those involved in nitrogen metabolism due to supply deficient free amino acids for maintenance of the C/N balance in source leaves of ApFS plants.

  14. Inter-relationships between single carbon units' metabolism and resting energy expenditure in weight-losing patients with small cell lung cancer. Effects of methionine supply and chemotherapy

    DEFF Research Database (Denmark)

    Sengeløv, H; Hansen, O P; Simonsen, L

    1994-01-01

    The one-carbon unit metabolism was investigated in 8 weight-losing patients with small cell carcinoma of the lung (SCLC). At diagnosis, 6 of the 8 patients had elevated formiminoglutamic acid (FIGLU) excretion after a histidine load, suggesting a lack of one-carbon units. In accordance...

  15. Inter-relationships between single carbon units' metabolism and resting energy expenditure in weight-losing patients with small cell lung cancer. Effects of methionine supply and chemotherapy

    DEFF Research Database (Denmark)

    Sengeløv, H; Hansen, O P; Simonsen, L

    1994-01-01

    The one-carbon unit metabolism was investigated in 8 weight-losing patients with small cell carcinoma of the lung (SCLC). At diagnosis, 6 of the 8 patients had elevated formiminoglutamic acid (FIGLU) excretion after a histidine load, suggesting a lack of one-carbon units. In accordance, a signifi...

  16. Effects of Pheretima Guillelmi Cultivation Time on Microbial Community Diversity and Characteristics of Carbon Metabolism in Vegetable Soil

    Directory of Open Access Journals (Sweden)

    ZHENG Xian-qing

    2015-12-01

    Full Text Available In order to study the effect of different biological tillage time (Pheretima guillelmi on soil microbial community metabolic functions in different soil depths, we set a location test in vegetable field at Chongming Island in Shanghai to analyze the changes of soil microbial community and carbon utilization abilities (Average well- color development, AWCD by using biolog eco-plate method. The three-year results showed that: Bio-tillage significantly improved microbial community activity, and with the increase of tillage years, biological tillage could make the average AWCD 3 to 7 times higher. The Simpson index and Shannon index of the biological tillage treatments were significantly higher than that of the control. The cumulative increase of 0~5 cm soil layer was 49 and 6.28 respectively, and the cumulative increase of 5~20 cm soil layer was 31 and 2.55 respectively. Earthworm bio-tillage significantly increased the soil microbial metabolic ability of 6 kinds of carbon sources, and increased the carbohydrate metabolism activity. In this study, earthworm bio-tillage is an effective way to increase the microbial activity of microbial soil.

  17. 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

    2014-11-01

    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 -1 day -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.

  18. Greenhouse gas footprint and the carbon flow associated with different solid waste management strategy for urban metabolism in Bangladesh.

    Science.gov (United States)

    Islam, K M Nazmul

    2017-02-15

    Greenhouse gas (GHG) emissions from municipal solid waste (MSW) and associated climate change consequences are gripping attention globally, while MSW management as a vital subsystem of urban metabolism significantly influences the urban carbon cycles. This study evaluates the GHG emissions and carbon flow of existing and proposed MSW management in Bangladesh through scenario analysis, including landfill with landfill gas (LFG) recovery, waste to energy (WtE), and material recovery facility (MRF). The analysis indicates that, scenario H 2 and H 5 emitted net GHGs -152.20kg CO 2 eq. and -140.32kg CO 2 eq., respectively, in comparison with 420.88kg CO 2 eq. of scenario H 1 for managing per ton of wastes during the reference year 2015. The annual horizontal carbon flux of the waste input was 319Gg and 158Gg during 2015 in Dhaka and Chittagong, respectively. An integrated strategy of managing the wastes in the urban areas of Bangladesh involving WtE incineration plant and LFG recovery to generate electricity as well as MRF could reverse back 209.46Gg carbon and 422.29Gg carbon to the Chittagong and Dhaka urban system, respectively. This study provides valuable insights for the MSW policy framework and revamp of existing MSW management practices with regards to reduction of GHGs emissions from the waste sector in Bangladesh. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. ESA Unveils Its New Comet Chaser.

    Science.gov (United States)

    1999-07-01

    The objective is to study one of these primordial objects at close quarters by placing a lander on its surface and chasing, with an orbiter, the comet for millions of kilometres through space. Comets - among the oldest (4.6 billion years!) and last altered objects in the solar system - are regarded as the building blocks from which the planets formed. Thus the Rosetta's discoveries will allow the scientists to learn more about birth and evolution of the planets and about the origin of life on the Earth. The final design of the Rosetta orbiter will be revealed for the first time at the Royal Society in London on 1 July when a 1:4 scale model will be unveiled by ESA's Director of Science, Prof.. Roger Bonnet. (The full size version of the spacecraft is 32 metres across, so large that it would stretch the entire width of a football pitch. Almost 90 of this is accounted for by the giant solar panels which are needed to provide electrical power in the dark depths of the Solar System). "Rosetta is a mission of major scientific importance," said Prof. Bonnet. "It will build on the discoveries made by Giotto and confirm ESA's leading role in the exploration of the Solar System and the Universe as a whole." The timing of this event has been chosen to coincide with the London meeting of the Rosetta Science Working Team and the second Earth flyby of the now non-operational Giotto spacecraft. In addition, the opening of the British Museum's 'Cracking Codes' Exhibition, for which the Rosetta Stone is the centrepiece, is set to take place on 10 July. The Rosetta mission. Rosetta is the third Cornerstone in ESA's 'Horizon 2000' long-term scientific programme. It will be launched by Ariane 5 rocket from Kourou spaceport in French Guiana in January 2003. In order to gain sufficient speed to reach the distant comet, Rosetta will require gravity assists from the Earth (twice) and Mars. After swinging around Mars in May 2005, Rosetta will return to Earth's vicinity in October 2005 and

  20. Linking carbon and nitrogen metabolism to depth distribution of submersed macrophytes using high ammonium dosing tests and a lake survey.

    Science.gov (United States)

    Yuan, Guixiang; Cao, Te; Fu, Hui; Ni, Leyi; Zhang, Xiaolin; Li, Wei; Song, Xin; Xie, Ping; Jeppesen, Erik

    2013-12-01

    Strategies of carbon (C) and nitrogen (N) utilisation are among the factors determining plant distribution. It has been argued that submersed macrophytes adapted to lower light environments are more efficient in maintaining C metabolic homeostasis due to their conservative C strategy and ability to balance C shortage. We studied how depth distributions of 12 submersed macrophytes in Lake Erhai, China, were linked to their C-N metabolic strategies when facing acute [Formula: see text] dosing.[Formula: see text] dosing changed C-N metabolism significantly by decreasing the soluble carbohydrate (SC) content and increasing the [Formula: see text]-N and free amino acid (FAA) content of plant tissues.The proportional changes in SC contents in the leaves and FAA contents in the stems induced by [Formula: see text] dosing were closely correlated (positive for SC and negative for FAA) with the colonising water depths of the plants in Lake Erhai, the plants adapted to lower light regimes being more efficient in maintaining SC and FAA homeostasis.These results indicate that conservative carbohydrate metabolism of submersed macrophytes allowed the plants to colonise greater water depths in eutrophic lakes, where low light availability in the water column diminishes carbohydrate production by the plants.

  1. The association between donor genetic variations in one-carbon metabolism pathway genes and hepatitis B recurrence after liver transplantation.

    Science.gov (United States)

    Lu, Di; Zhuo, Jianyong; Yang, Modan; Wang, Chao; Linhui, Pan; Xie, Haiyang; Xu, Xiao; Zheng, Shusen

    2018-04-05

    Hepatitis B recurrence adversely affects patients' survival after liver transplantation. This study aims to find association between donor gene variations of one carbon metabolism and post-transplant hepatitis B recurrence. This study enrolled 196 patients undergoing liver transplantation for HBV related end-stage liver diseases. We detected 11 single nucleotide polymorphisms (SNP) of 7 one-carbon metabolism pathway genes (including MTHFR, MTR, MTRR, ALDH1L1, GART, SHMT1 and CBS) in donor livers and analyzed their association with HBV reinfection after liver transplantation. Hepatitis B recurrence was observed in 19 of the 196 patients (9.7%) undergoing liver transplantation. Hepatitis B recurrence significantly affected post-transplant survival in the 196 patients (p = 0.018), and correlate with tumor recurrence in the subgroup of HCC patients (n = 99, p = 0.006). Among the 11 SNPs, donor liver mutation in rs1979277 (G > A) was adversely associated with post-transplant hepatitis B recurrence (p = 0.042). In the subgroup of HCC patients, survival analysis showed donor liver mutations in rs1801133 (G > A) and rs1979277 (G > A) were risk factors for hepatitis B recurrence (p B recurrence in non-HCC patients (n = 97, p > 0.05). Hepatitis B recurrence impaired post-transplant survival. Donor liver genetic variations in one-carbon metabolism pathway genes were significantly associated with post-transplant hepatitis B recurrence. Copyright © 2017. Published by Elsevier B.V.

  2. 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

  3. Generation of nitric oxide from nitrite by carbonic anhydrase: a possible link between metabolic activity and vasodilation

    DEFF Research Database (Denmark)

    Aamand, Rasmus; Dalsgaard, Thomas; Jensen, Frank Bo

    2009-01-01

    In catalyzing the reversible hydration of CO2 to bicarbonate and protons, the ubiquitous enzyme carbonic anhydrase (CA) plays a crucial role in CO2 transport, in acid-base balance, and in linking local acidosis to O2 unloading from hemoglobin. Considering the structural similarity between...... bicarbonate and nitrite, we hypothesized that CA uses nitrite as a substrate to produce the potent vasodilator nitric oxide (NO) to increase local blood flow to metabolically active tissues. Here we show that CA readily reacts with nitrite to generate NO, particularly at low pH, and that the NO produced...

  4. Effects of photoperiodism on the metabolism of carbon compounds and the migration of these products in tobacco

    International Nuclear Information System (INIS)

    Farineau, Jack

    1961-01-01

    This research thesis addressed the influence of photoperiodism on migrations. The author more particularly studied migrations of carbon-compound metabolism products by using a tobacco leaf in presence of "1"4CO_2, and which thus contained a high quantity of radioactive compounds. Some experiments were performed on short durations (few hours), and others on longer durations (15 days). As far as the first ones were concerned, the author studied the content of the petiole and of the terminal bud, and the first reactions of integration of carbon 14 compounds of the sap in the leaf. As far as the second type of experiments is concerned, the author measured the quantities of radioactive products migrating towards the terminal bud [fr

  5. 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

  6. Effects of Graphene Oxide and Oxidized Carbon Nanotubes on the Cellular Division, Microstructure, Uptake, Oxidative Stress, and Metabolic Profiles.

    Science.gov (United States)

    Hu, Xiangang; Ouyang, Shaohu; Mu, Li; An, Jing; Zhou, Qixing

    2015-09-15

    Nanomaterial oxides are common formations of nanomaterials in the natural environment. Herein, the nanotoxicology of typical graphene oxide (GO) and carboxyl single-walled carbon nanotubes (C-SWCNT) was compared. The results showed that cell division of Chlorella vulgaris was promoted at 24 h and then inhibited at 96 h after nanomaterial exposure. At 96 h, GO and C-SWCNT inhibited the rates of cell division by 0.08-15% and 0.8-28.3%, respectively. Both GO and C-SWCNT covered the cell surface, but the uptake percentage of C-SWCNT was 2-fold higher than that of GO. C-SWCNT induced stronger plasmolysis and mitochondrial membrane potential loss and decreased the cell viability to a greater extent than GO. Moreover, C-SWCNT-exposed cells exhibited more starch grains and lysosome formation and higher reactive oxygen species (ROS) levels than GO-exposed cells. Metabolomics analysis revealed significant differences in the metabolic profiles among the control, C-SWCNT and GO groups. The metabolisms of alkanes, lysine, octadecadienoic acid and valine was associated with ROS and could be considered as new biomarkers of ROS. The nanotoxicological mechanisms involved the inhibition of fatty acid, amino acid and small molecule acid metabolisms. These findings provide new insights into the effects of GO and C-SWCNT on cellular responses.

  7. 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. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  8. Photoperiod length paces the temporal orchestration of cell cycle and carbon-nitrogen metabolism in Crocosphaera watsonii.

    Science.gov (United States)

    Dron, Anthony; Rabouille, Sophie; Claquin, Pascal; Talec, Amélie; Raimbault, Virginie; Sciandra, Antoine

    2013-12-01

    We analysed the effect of photoperiod length (PPL) (16:8 and 8:16 h of light-dark regime, named long and short PPL, respectively) on the temporal orchestration of the two antagonistic, carbon and nitrogen acquisitions in the unicellular, diazotrophic cyanobacterium Crocosphaera watsonii strain WH8501 growing diazotrophically. Carbon and nitrogen metabolism were monitored at high frequency, and their patterns were compared with the cell cycle progression. The oxygen-sensitive N2 fixation process occurred mainly during the dark period, where photosynthesis cannot take place, inducing a light-dark cycle of cellular C : N ratio. Examination of circadian patterns in the cell cycle revealed that cell division occurred during the midlight period, (8 h and 4 h into the light in the long and short PPL conditions, respectively), thus timely separated from the energy-intensive diazotrophic process. Results consistently show a nearly 5 h time lag between the end of cell division and the onset of N2 fixation. Shorter PPLs affected DNA compaction of C. watsonii cells and also led to a decrease in the cell division rate. Therefore, PPL paces the growth of C. watsonii: a long PPL enhances cell division while a short PPL favours somatic growth (biomass production) with higher carbon and nitrogen cell contents. © 2013 Society for Applied Microbiology and John Wiley & Sons Ltd.

  9. 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

  10. 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 th...

  11. Unveiling Reality of the Mind: Cultural Arbitrary of Consumerism

    Science.gov (United States)

    Choi, Su-Jin

    2012-01-01

    This paper discusses the cultural arbitrary of consumerism by focusing on a personal realm. That is, I discuss what consumerism appeals to and how it flourishes in relation to our minds. I argue that we need to unveil reality of the mind, be aware of ourselves in relation to the perpetuation of consumerism, in order to critically intervene in the…

  12. Book review: Unveiling the Whale: Discourses on Whales and Whaling

    Science.gov (United States)

    John Schelhas

    2012-01-01

    Whaling represents one of the most internationally controversial and highly polarized environmental issues of recent times. Arne Kalland, in Unveiling the Whale: Discourses on Whales and Whaling, examines the whaling issue from the perspective of a pro-whaling country with an emphasis on analysis of discourse in international arenas, primarily the International Whaling...

  13. Proofpoint unveils the industry's most advanced anti-spam laboratory

    CERN Multimedia

    2003-01-01

    "Proofpoint, Inc., the leader in large enterprise anti-spam solutions, today unveiled its Anti-Spam Laboratory, the world's most advanced center for spam research and analysis, and the first to be based on advanced Machine Learning science" (1 page).

  14. First National Picture of Trends in the Humanities Is Unveiled

    Science.gov (United States)

    Howard, Jennifer

    2009-01-01

    When it comes to hard data about what they do, policy makers and educators in the humanities have been mostly left out in the cold, forced to rely on isolated statistics that do not give an overview of the field. That changed this month, as the American Academy of Arts and Sciences unveiled the prototype of its long-awaited Humanities Indicators…

  15. Effect of silver ion, carbon dioxide, and oxygen on ethylene action and metabolism

    International Nuclear Information System (INIS)

    Beyer, E.M. Jr.

    1979-01-01

    The relationship between ethylene action and metabolism was investigated in the etiolated pea seedling (Pisum sativum L. cv. Alaska) by inhibiting ethylene action with Ag + , high CO 2 , and low O 2 and then determining if ethylene metabolism was inhibited in a similar manner. Ag + (100 milligrams per liter) was clearly the most potent antiethylene treatment. Ag + pretreatment inhibited the growth retarding action of 0.2 microliters per liter ethylene by 48% and also inhibited the incorporation of 14 C 2 H 4 into pea tips by the same amount. As the ethylene concentration was increased from 0.2 to 30 microliters per liter, the effectiveness of Ag + in reducing ethylene action and metabolism declined in a similar fashion. Although Ag + significantly inhibited the incorporation of 14 C 2 H 4 into tissue metabolites, the oxidation of 14 C 2 H 4 to 14 CO 2 was unaffected. CO 2 (7%) inhibited ethylene-induced growth retardation but its effectiveness diminished at a greater rate than that of Ag + with increasing ethylene concentration. High CO 2 had just the opposite effect of Ag + since it inhibited 14 C 2 H 4 oxidation to 14 CO 2 without affecting tissue incorporation. In contrast to Ag + , CO 2 did not inhibit ethylene action and metabolism to exactly the same extent, and the inhibition of metabolism did not rapidly decline with increasing 14 C 2 H 4 concentration. However, high CO 2 did alter the ratio of 14 C 2 H 4 tissue incorporation to 14 CO 2 production in a manner consistent with changes in ethylene effectiveness. Lowering the O 2 concentration to 5% reduced ethylene-induced growth retardation and inhibited 14 C 2 H 4 tissue incorporation and oxidation to 14 CO 2 by 26 and 45%, respectively. Low O 2 reduced pea seedling growth under these conditions thereby severely limiting its usefulness as a specific antiethylene treatment

  16. Anaplerotic metabolism of Aspergillus nidulans and its effect on biomass synthesis in carbon limited chemostats

    Energy Technology Data Exchange (ETDEWEB)

    Bushell, M E; Bull, A T

    1981-01-01

    Anaplerotic fixation of carbon dioxide by the fungus Aspergillus nidulans when grown under carbon-limited conditions was mediated by pyruvate carboxylase and a phosphoenol pyruvate (PEP)-metabolising enzyme which has been tentatively designated as PEP carboxylase. The activities of both enzymes were growth rate dependent and measurements of H/sup 14/CO/sub 3/ incorporation by growing mycelium indicated that they were responsible for almost all the assimilated carbon dioxide. In carbon-limited chemostats, the maximum rate of bicarbonate assimilation occurred at a dilution rate of 0.11 h/sup -1/, equivalent to 1/2 ..mu..sub(max). The affinity of the pyruvate carboxylase for bicarbonate was twice of the PEP carboxylase under the conditions of growth used. The effect of changing the bicarbonate concentration in carbon-limited chemostats was substantial: increasing the HCO/sup -//sub 3/ concentration over the range 0.7-2.8 mM enhanced biomass synthesis by 22%. Over-shoots in bicarbonate assimilation and carboxylase activity occurred when steady state chemostat cultures were subjected to a step down in dilution rate.

  17. 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.

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

    Science.gov (United States)

    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.

  19. 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 ...

  20. Discharge modulates stream metabolism dependence on fine particulate organic carbon in a Mediterranean WWTP-influenced stream

    Science.gov (United States)

    Drummond, J. D.; Bernal, S.; Meredith, W.; Schumer, R.; Martí Roca, E.

    2017-12-01

    Waste water treatment plant (WWTP) effluents constitute point source inputs of fine sediment, nutrients, carbon, and microbes to stream ecosystems. A range of responses to these inputs may be observed in recipient streams, including increases in respiration rates, which augment CO2 emissions to the atmosphere. Yet, little is known about which fractions of organic carbon (OC) contribute the most to stream metabolism in WWTP-influenced streams. Fine particulate OC (POC) represents ca. 40% of the total mass of OC in river networks, and is generally more labile than dissolved OC. Therefore, POC inputs from WWTPs could contribute disproportionately to higher rates of heterotrophic metabolism by stream microbial communities. The aim of this study was to investigate the influence of POC inputs from a WWTP effluent on the metabolism of a Mediterranean stream over a wide range of hydrologic conditions. We hypothesized that POC inputs would have a positive effect on respiration rates, and that the response to POC availability would be larger during low flows when the dilution capacity of the recipient stream is negligible. We focused on the easily resuspended fine sediment near the sediment-water interface (top 3 cm), as this region is a known hot spot for biogeochemical processes. For one year, samples of resuspended sediment were collected bimonthly at 7 sites from 0 to 800 m downstream of the WWTP point source. We measured total POC, organic matter (OM) content (%), and the associated metabolic activity of the resuspended sediment using the resazurin-resorufin smart tracer system as a proxy for aerobic ecosystem respiration. Resuspended sediment showed no difference in total POC over the year, while the OM content increased with decreasing discharge. This result together with the decreasing trend of total POC observed downstream of the point source during autumn after a long dry period, suggests that the WWTP effluent was the main contributor to stream POC. Furthermore

  1. Circulation, metabolism, and ventilation during prolonged exposure to carbon monoxide and to high altitude

    Energy Technology Data Exchange (ETDEWEB)

    Klausen, K.; Rasmussen, B; Gjellerod, H.; Madsen, H.; Petersen, E.

    1968-01-01

    Eight volunteers were exposed to CO (13% COHb) or high altitude (3454 m). There was no change in circulation, metabolism, or ventilation during CO exposure. With similar arterial O/sub 2/ concentration from high-altitude, V/sub e/ (BTPS) increased, Pa/sub CO/sub 2// decreased. Regulating mechanisms respond to a decrease in Pa/sub CO/sub 2// rather than a gereral lack in tissue O/sub 2/ per se.

  2. 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

    Polyol production has been studied in Aspergillus niger under different conditions. Fermentations have been run using high concentration of glucose or xylose as carbon source and ammonium or nitrate as nitrogen source. The growth of biomass, as freely dispersed hyphae, led to an increase of medium...

  3. Effects of dissolved carbon dioxide on energy metabolism and stress responses in European seabass (Dicentrarchus labrax)

    NARCIS (Netherlands)

    Santos, G.A.; Schrama, J.W.; Capelle, J.; Rombout, J.H.W.M.; Verreth, J.A.J.

    2013-01-01

    Elevated carbon dioxide concentrations reduce feed intake and growth in several fish species and induce stress responses. In this study, the effects of moderately elevated CO2 levels on performance, energy partitioning, swimming activity and stress response in European seabass were assessed.

  4. 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.

  5. Acquisition and metabolism of carbon in the Ochrophyta other than diatoms

    Czech Academy of Sciences Publication Activity Database

    Raven, J. A.; Giordano, Mario

    2017-01-01

    Roč. 372, č. 1728 (2017), s. 1-11, č. článku 20160400. ISSN 1471-2970 Institutional support: RVO:61388971 Keywords : CO2 concentrating mechanism * Rubisco * inorganic carbon Subject RIV: EE - Microbiology, Virology OBOR OECD: Microbiology

  6. Metabolism of tritium- and carbon-14-labeled tiamulin in dogs, rats, and pigs.

    Science.gov (United States)

    Dreyfuss, J; Singhvi, S M; Shaw, J M; Egli, P; Ross, J J; Czok, R; Nefzger-Biessels, M; Battig, F; Schuster, I; Schmook, F

    1979-05-01

    The metabolism of tiamulin hydrogen fumarate, labeled with 3H, 14C, or both, was studied in dogs, rats, and weanling pigs. After a dose of radiolabeled tiamulin, all three species excreted more radioactivity in feces (via bile) than in urine. Dogs absorbed 86% of a single oral dose of tiamulin-3H, and the disposition of the compound was similar after a single or multiple dosage regimen. The ratio of antimicrobial activity to total radioactivity in dog plasma was only about 0.25, and was still less in dog urine. After dosing with tiamulin-14C, rats and pigs excreted at least 1% of the dose as 14CO2 in expired air. In dual-labeled studies, pigs excreted less total 14C than 3H and had greater residues of 14C than 3H in edible tissues, blood, and plasma. After the administration of tiamulin-14C to pigs, radioactivity was incorporated into liver glycogen, indicating metabolic cleavage of the side chain of tiamulin. Tiamulin-3H is the isotopically-labeled compound of choice for studying metabolism and tissue residues in animals.

  7. Nicotinamide supplementation phenocopies SIR2 inactivation by modulating carbon metabolism and respiration during yeast chronological aging.

    Science.gov (United States)

    Orlandi, Ivan; Pellegrino Coppola, Damiano; Strippoli, Maurizio; Ronzulli, Rossella; Vai, Marina

    2017-01-01

    Nicotinamide (NAM), a form of vitamin B 3 , is a byproduct and noncompetitive inhibitor of the deacetylation reaction catalyzed by Sirtuins. These represent a family of evolutionarily conserved NAD + -dependent deacetylases that are well-known critical regulators of metabolism and aging and whose founding member is Sir2 of Saccharomyces cerevisiae. Here, we investigated the effects of NAM supplementation in the context of yeast chronological aging, the established model for studying aging of postmitotic quiescent mammalian cells. Our data show that NAM supplementation at the diauxic shift results in a phenocopy of chronologically aging sir2Δ cells. In fact, NAM-supplemented cells display the same chronological lifespan extension both in expired medium and extreme Calorie Restriction. Furthermore, NAM allows the cells to push their metabolism toward the same outcomes of sir2Δ cells by elevating the level of the acetylated Pck1. Both these cells have the same metabolic changes that concern not only anabolic pathways such as an increased gluconeogenesis but also respiratory activity in terms both of respiratory rate and state of respiration. In particular, they have a higher respiratory reserve capacity and a lower non-phosphorylating respiration that in concert with a low burden of superoxide anions can affect positively chronological aging. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  8. Soybeans Grown in the Chernobyl Area Produce Fertile Seeds that Have Increased Heavy Metal Resistance and Modified Carbon Metabolism

    Science.gov (United States)

    Klubicová, Katarína; Danchenko, Maksym; Skultety, Ludovit; Berezhna, Valentyna V.; Uvackova, Lubica; Rashydov, Namik M.; Hajduch, Martin

    2012-01-01

    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. PMID:23110204

  9. 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.

  10. Rerouting of carbon flux in a glycogen mutant of cyanobacteria assessed via isotopically non-stationary 13 C metabolic flux analysis.

    Science.gov (United States)

    Hendry, John I; Prasannan, Charulata; Ma, Fangfang; Möllers, K Benedikt; Jaiswal, Damini; Digmurti, Madhuri; Allen, Doug K; Frigaard, Niels-Ulrik; Dasgupta, Santanu; Wangikar, Pramod P

    2017-10-01

    Cyanobacteria, which constitute a quantitatively dominant phylum, have attracted attention in biofuel applications due to favorable physiological characteristics, high photosynthetic efficiency and amenability to genetic manipulations. However, quantitative aspects of cyanobacterial metabolism have received limited attention. In the present study, we have performed isotopically non-stationary 13 C metabolic flux analysis (INST- 13 C-MFA) to analyze rerouting of carbon in a glycogen synthase deficient mutant strain (glgA-I glgA-II) of the model cyanobacterium Synechococcus sp. PCC 7002. During balanced photoautotrophic growth, 10-20% of the fixed carbon is stored in the form of glycogen via a pathway that is conserved across the cyanobacterial phylum. Our results show that deletion of glycogen synthase gene orchestrates cascading effects on carbon distribution in various parts of the metabolic network. Carbon that was originally destined to be incorporated into glycogen gets partially diverted toward alternate storage molecules such as glucosylglycerol and sucrose. The rest is partitioned within the metabolic network, primarily via glycolysis and tricarboxylic acid cycle. A lowered flux toward carbohydrate synthesis and an altered distribution at the glucose-1-phosphate node indicate flexibility in the network. Further, reversibility of glycogen biosynthesis reactions points toward the presence of futile cycles. Similar redistribution of carbon was also predicted by Flux Balance Analysis. The results are significant to metabolic engineering efforts with cyanobacteria where fixed carbon needs to be re-routed to products of interest. Biotechnol. Bioeng. 2017;114: 2298-2308. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  11. Impact of folic acid intake during pregnancy on genomic imprinting of IGF2/H19 and 1-carbon metabolism.

    Science.gov (United States)

    Tserga, Aggeliki; Binder, Alexandra M; Michels, Karin B

    2017-12-01

    Folic acid is an essential component of 1-carbon metabolism, which generates methyl groups for DNA methylation. Disruption of genomic imprinting leads to biallelic expression which may affect disease susceptibility possibly reflected in high levels of S -adenosyl-homocysteine (SAH) and low levels of S -adenosyl-methionine (SAM). We investigated the association between folic acid supplementation during pregnancy and loss of imprinting (LOI) of IGF2 and H19 genes in placentas and cord blood of 90 mother-child dyads in association with the methylenetetrahydrofolate reductase ( MTHFR ) genotype. Pyrosequencing was used to evaluate deviation from monoallelic expression among 47 placentas heterozygous for H19 and 37 placentas and cord blood tissues heterozygous for IGF2 and H19 methylation levels of 48 placentas. We detected relaxation of imprinting (ROI) and LOI of H19 in placentas not associated with differences in methylation levels of the H19ICR. Placentas retained monoallelic allele-specific gene expression of IGF2 , but 32.4% of cord blood samples displayed LOI of IGF2 and 10.8% showed ROI. High SAH levels were significantly associated with low H19 methylation. An interesting positive association between SAM/SAH ratio and high H19 methylation levels was detected among infants with low B 12 levels. Our data suggest profound differences in regulation of imprinting in placenta and cord blood; a lack of correlation of the methylome, transcriptome, and proteome; and a complex regulatory feedback network between free methyl groups and genomic imprinting at birth.-Tserga, A., Binder, A. M., Michels, K. B. Impact of folic acid intake during pregnancy on genomic imprinting of IGF2/H19 and 1-carbon metabolism. © FASEB.

  12. 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.

  13. The Glycerate and Phosphorylated Pathways of Serine Synthesis in Plants: The Branches of Plant Glycolysis Linking Carbon and Nitrogen Metabolism.

    Science.gov (United States)

    Igamberdiev, Abir U; Kleczkowski, Leszek A

    2018-01-01

    Serine metabolism in plants has been studied mostly in relation to photorespiration where serine is formed from two molecules of glycine. However, two other pathways of serine formation operate in plants and represent the branches of glycolysis diverging at the level of 3-phosphoglyceric acid. One branch (the glycerate - serine pathway) is initiated in the cytosol and involves glycerate formation from 3-phosphoglycerate, while the other (the phosphorylated serine pathway) operates in plastids and forms phosphohydroxypyruvate as an intermediate. Serine formed in these pathways becomes a precursor of glycine, formate and glycolate accumulating in stress conditions. The pathways can be linked to GABA shunt via transamination reactions and via participation of the same reductase for both glyoxylate and succinic semialdehyde. In this review paper we present a hypothesis of the regulation of redox balance in stressed plant cells via participation of the reactions associated with glycerate and phosphorylated serine pathways. We consider these pathways as important processes linking carbon and nitrogen metabolism and maintaining cellular redox and energy levels in stress conditions.

  14. Single-walled carbon nanotubes disturbed the immune and metabolic regulation function 13-weeks after a single intratracheal instillation

    Energy Technology Data Exchange (ETDEWEB)

    Park, Eun-Jung, E-mail: pejtoxic@hanmail.net [Myunggok Eye Research Institute, Konyang University, Daejeon 302-718 (Korea, Republic of); Hong, Young-Shick [Division of Food and Nutrition, Chonnam National University, Yongbong-Ro, Buk-Gu, Gwangju 500-757 (Korea, Republic of); Lee, Byoung-Seok [Toxicologic Pathology Center, Korea Institute of Toxicology, Daejeon (Korea, Republic of); Yoon, Cheolho [Seoul Center, Korea Basic Science Institute, Seoul 126-16 (Korea, Republic of); Jeong, Uiseok; Kim, Younghun [Department of Chemical Engineering, Kwangwoon University, Seoul 139-701 (Korea, Republic of)

    2016-07-15

    Due to their unique physicochemical properties, the potential health effects of single-walled carbon nanotubes (SWCNTs) have attracted continuous attention together with their extensive application. In this study, we aimed to identify local and systemic health effects following pulmonary persistence of SWCNTs. As expected, SWCNTs remained in the lung for 13 weeks after a single intratracheal instillation (50, 100, and 200 μg/kg). In the lung, the total number of cells and the percentages of lymphocytes and neutrophils significantly increased at 200 μg/kg compared to the control, and the Th1-polarized immune response was induced accompanying enhanced expression of tissue damage-related genes and increased release of chemokines. Additionally, SWCNTs enhanced the expression of antigen presentation-related proteins on the surface of antigen-presenting cells, however, maturation of dendritic cells was inhibited by their persistence. As compared to the control, a significant increase in the percentage of neutrophils and a remarkable decrease of BUN and potassium level were observed in the blood of mice treated with the highest dose. This was accompanied by the down-regulation of the expression of antigen presentation-related proteins on splenocytes. Moreover, protein and glucose metabolism were disturbed with an up-regulation of fatty acid β-oxidation. Taken together, we conclude that SWCNTs may induce adverse health effects by disturbing immune and metabolic regulation functions in the body. Therefore, careful application of SWCNTs is necessary for the enforcement of safety in nano-industries. - Highlights: • We evaluated local and systemic health effects following persistence of SWCNTs. • SWCNTs remained in the lung for 13 weeks after a single intratracheal instillation. • Th1-polarized immune response was induced in the lung. • The expression of antigen presentation-related proteins was altered. • Immune and metabolic regulation function were disturbed.

  15. Transcriptional regulation of respiration in yeast metabolizing differently repressive carbon substrates

    OpenAIRE

    Fendt, Sarah-Maria; Sauer, Uwe

    2010-01-01

    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 t...

  16. Microbial metabolic potential for carbon degradation and nutrient (nitrogen and phosphorus) acquisition in an ombrotrophic peatland.

    Science.gov (United States)

    Lin, Xueju; Tfaily, Malak M; Green, Stefan J; Steinweg, J Megan; Chanton, Patrick; Imvittaya, Aopeau; Chanton, Jeffrey P; Cooper, William; Schadt, Christopher; Kostka, Joel E

    2014-06-01

    This study integrated metagenomic and nuclear magnetic resonance (NMR) spectroscopic approaches to investigate microbial metabolic potential for organic matter decomposition and nitrogen (N) and phosphorus (P) acquisition in soils of an ombrotrophic peatland in the Marcell Experimental Forest (MEF), Minnesota, USA. This analysis revealed vertical stratification in key enzymatic pathways and taxa containing these pathways. Metagenomic analyses revealed that genes encoding laccases and dioxygenases, involved in aromatic compound degradation, declined in relative abundance with depth, while the relative abundance of genes encoding metabolism of amino sugars and all four saccharide groups increased with depth in parallel with a 50% reduction in carbohydrate content. Most Cu-oxidases were closely related to genes from Proteobacteria and Acidobacteria, and type 4 laccase-like Cu-oxidase genes were >8 times more abundant than type 3 genes, suggesting an important and overlooked role for type 4 Cu-oxidase in phenolic compound degradation. Genes associated with sulfate reduction and methanogenesis were the most abundant anaerobic respiration genes in these systems, with low levels of detection observed for genes of denitrification and Fe(III) reduction. Fermentation genes increased in relative abundance with depth and were largely affiliated with Syntrophobacter. Methylocystaceae-like small-subunit (SSU) rRNA genes, pmoA, and mmoX genes were more abundant among methanotrophs. Genes encoding N2 fixation, P uptake, and P regulons were significantly enriched in the surface peat and in comparison to other ecosystems, indicating N and P limitation. Persistence of inorganic orthophosphate throughout the peat profile in this P-limiting environment indicates that P may be bound to recalcitrant organic compounds, thus limiting P bioavailability in the subsurface. Comparative metagenomic analysis revealed a high metabolic potential for P transport and starvation, N2 fixation, and

  17. The effect of zilpaterol hydrochloride supplementation on energy metabolism and nitrogen and carbon retention of steers fed at maintenance and fasting intake levels

    Science.gov (United States)

    An indirect calorimetry trial examined energy metabolism, apparent nutrient digestibility (appND), carbon retention (CR) and nitrogen retention (NR) of cattle supplemented with zilpaterol hydrochloride (Z). Beef steers (n=20; 463 ± 14 kg) blocked (n=5) by weight and source were individually fed and ...

  18. 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.

  19. Why devote an entire issue to the topic of how nutrients in one-carbon metabolism play roles in modern medicine?

    Science.gov (United States)

    The vitamins that serve as essential co-factors in one-carbon metabolism-B2, B6, B9 (folate), and B12-have had a long and storied history in the field of medicine over the past two centuries, as have related intermediary metabolites such as methionine, homocysteine, betaine and choline. The megalobl...

  20. Effect of carbon tetrachloride on glycogen metabolism in fasted and refed mice

    International Nuclear Information System (INIS)

    Pushpendran, C.K.; Shenoy, B.V.; Eapen, J.

    1977-01-01

    Hepatic glycogen was depleted rapidly in fasted mice treated with CCl 4 . Glycogen breakdown was slow when CCl 4 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 CCl 4 injection. The incorporation of glucose-U- 14 C into glycogen was higher in mice which were refed before CCl 4 administration than in fasted mice treated with the hepatotoxin. The specific activity of lactate was higher in CCl 4 treated mice. The data suggested differences in glycogen metabolism of fasted and refed mice in response to CCl 4 treatment. (author)

  1. Carbon and hydrogen metabolism of green algae in light and dark

    Energy Technology Data Exchange (ETDEWEB)

    1990-01-01

    After adaptation to a hydrogen metabolism, Chlamydomonas reinhardtii can photoanaerobically metabolize acetate with the evolution of H{sub 2} and CO{sub 2}. An enzyme profile of the chloroplastic, cytoplasmic, and mitochondrial fractions were obtained with a cellular fractionation procedure that incorporated cell wall removal by autolysine, digestion of the plasmalemma with digitonin and fractionation by differential centrifugation on a Percoll step gradient. The sequence of events leading to the photo-evolution of H{sub 2} from acetate includes the conversion of acetate into succinate via the extraplastidic glyoxylate cycle, the oxidation of succinate to fumarate by chloroplastic succinic dehydrogenase and the oxidation of malate to oxaloacetate in the chloroplast by NAD dependent malate dehydrogenase. The level of potential activity of the enzymes was sufficient to accommodate the observed rate of gas evolution. The isolated darkened chloroplast evolves aerobically CO{sub 2} from glucose indicating a chloroplastic respiratory pathway. Evolution of CO{sub 2} is blocked by mitochondrial inhibitors.

  2. Short-term postharvest carbon dioxide treatments induce selective molecular and metabolic changes in grape berries.

    Science.gov (United States)

    Becatti, Elisa; Chkaiban, Lamia; Tonutti, Pietro; Forcato, Claudio; Bonghi, Claudio; Ranieri, Anna Maria

    2010-07-14

    Detached wine grapes ( Vitis vinifera cv. 'Trebbiano', white skinned) were treated for 3 days with 30 kPa of CO(2) and then transferred to air for an additional 9 days to partially dehydrate (about 20% weight loss). At the end of the CO(2) treatment on withering berries, total polyphenols and flavonoids were maintained in the skin, but to a more limited extent in the pulp. An induction of the proanthocyanidin synthesis appeared to be one of the responses to the treatment because both (+)-catechin and (-)-epicatechin concentrations increased in the skin. The skin and pulp of the grape berries showed different molecular responses to a high CO(2) treatment. As revealed by microarray hybridizations, 217 and 75 genes appeared differentially expressed in the skin and pulp of treated samples, respectively. Functional categorization and gene enrichment analyses pointed out that epicarp cells undergo more pronounced changes in transcript profiling at the end of the incubation period. Highly represented categories in both tissues were related to protein, stress, transcript, RNA, and hormone (ethylene, ABA) metabolism. Fermentation, CHO metabolism, and redox regulation functional categories were represented only in the skin.

  3. Fermentation of Xylose Causes Inefficient Metabolic State Due to Carbon/Energy Starvation and Reduced Glycolytic Flux in Recombinant Industrial Saccharomyces cerevisiae

    Science.gov (United States)

    Matsushika, Akinori; Nagashima, Atsushi; Goshima, Tetsuya; Hoshino, Tamotsu

    2013-01-01

    In the present study, comprehensive, quantitative metabolome analysis was carried out on the recombinant glucose/xylose-cofermenting S. cerevisiae strain MA-R4 during fermentation with different carbon sources, including glucose, xylose, or glucose/xylose mixtures. Capillary electrophoresis time-of-flight mass spectrometry was used to determine the intracellular pools of metabolites from the central carbon pathways, energy metabolism pathways, and the levels of twenty amino acids. When xylose instead of glucose was metabolized by MA-R4, glycolytic metabolites including 3- phosphoglycerate, 2- phosphoglycerate, phosphoenolpyruvate, and pyruvate were dramatically reduced, while conversely, most pentose phosphate pathway metabolites such as sedoheptulose 7- phosphate and ribulose 5-phosphate were greatly increased. These results suggest that the low metabolic activity of glycolysis and the pool of pentose phosphate pathway intermediates are potential limiting factors in xylose utilization. It was further demonstrated that during xylose fermentation, about half of the twenty amino acids declined, and the adenylate/guanylate energy charge was impacted due to markedly decreased adenosine triphosphate/adenosine monophosphate and guanosine triphosphate/guanosine monophosphate ratios, implying that the fermentation of xylose leads to an inefficient metabolic state where the biosynthetic capabilities and energy balance are severely impaired. In addition, fermentation with xylose alone drastically increased the level of citrate in the tricarboxylic acid cycle and increased the aromatic amino acids tryptophan and tyrosine, strongly supporting the view that carbon starvation was induced. Interestingly, fermentation with xylose alone also increased the synthesis of the polyamine spermidine and its precursor S-adenosylmethionine. Thus, differences in carbon substrates, including glucose and xylose in the fermentation medium, strongly influenced the dynamic metabolism of MA-R4

  4. Carbon nanotubes toxicology and effects on metabolism and immunological modification in vitro and in vivo

    International Nuclear Information System (INIS)

    Chiaretti, M; Mazzanti, G; Mastrangelo, S; Di Sotto, A; Bosco, S; Porta, N; Deriu, G; Bellucci, S; Balasubramanian, C; De Bellis, G; Micciulla, F; Tiberia, A; Cucina, A; Le Foche, F; Carru, G A; Masciangelo, R; Chiaretti, A M

    2008-01-01

    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

  5. Interaction of Sulfate Assimilation with Carbon and Nitrogen Metabolism in Lemna minor1

    Science.gov (United States)

    Kopriva, Stanislav; Suter, Marianne; von Ballmoos, Peter; Hesse, Holger; Krähenbühl, Urs; Rennenberg, Heinz; Brunold, Christian

    2002-01-01

    Cysteine synthesis from sulfide and O-acetyl-l-serine (OAS) is a reaction interconnecting sulfate, nitrogen, and carbon assimilation. Using Lemna minor, we analyzed the effects of omission of CO2 from the atmosphere and simultaneous application of alternative carbon sources on adenosine 5′-phosphosulfate reductase (APR) and nitrate reductase (NR), the key enzymes of sulfate and nitrate assimilation, respectively. Incubation in air without CO2 led to severe decrease in APR and NR activities and mRNA levels, but ribulose-1,5-bisphosphate carboxylase/oxygenase was not considerably affected. Simultaneous addition of sucrose (Suc) prevented the reduction in enzyme activities, but not in mRNA levels. OAS, a known regulator of sulfate assimilation, could also attenuate the effect of missing CO2 on APR, but did not affect NR. When the plants were subjected to normal air after a 24-h pretreatment in air without CO2, APR and NR activities and mRNA levels recovered within the next 24 h. The addition of Suc and glucose in air without CO2 also recovered both enzyme activities, with OAS again influenced only APR. 35SO42− feeding showed that treatment in air without CO2 severely inhibited sulfate uptake and the flux through sulfate assimilation. After a resupply of normal air or the addition of Suc, incorporation of 35S into proteins and glutathione greatly increased. OAS treatment resulted in high labeling of cysteine; the incorporation of 35S in proteins and glutathione was much less increased compared with treatment with normal air or Suc. These results corroborate the tight interconnection of sulfate, nitrate, and carbon assimilation. PMID:12428005

  6. 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

  7. Nitrogen Addition Exacerbates the Negative Effects of Low Temperature Stress on Carbon and Nitrogen Metabolism in Moss

    Directory of Open Access Journals (Sweden)

    Bin-Yang Liu

    2017-08-01

    Full Text Available Global environmental changes are leading to an increase in localized abnormally low temperatures and increasing nitrogen (N deposition is a phenomenon recognized worldwide. Both low temperature stress (LTS and excess N induce oxidative stress in plants, and excess N also reduces their resistance to LTS. Mosses are primitive plants that are generally more sensitive to alterations in environmental factors than vascular species. To study the combined effects of N deposition and LTS on carbon (C and N metabolism in moss, two moss species, Pogonatum cirratum subsp. fuscatum, and Hypnum plumaeforme, exposed to various concentrations of nitrate (KNO3 or ammonium (NH4Cl, were treated with or without LTS. C/N metabolism indices were then monitored, both immediately after the stress and after a short recovery period (10 days. LTS decreased the photosystem II (PSII performance index and inhibited non-cyclic photophosphorylation, ribulose-1,5-bisphosphate carboxylase, and glutamine synthetase activities, indicating damage to PSII and reductions in C/N assimilation in these mosses. LTS did not affect cyclic photophosphorylation, sucrose synthase, sucrose-phosphate synthase, and NADP-isocitrate dehydrogenase activities, suggesting a certain level of energy and C skeleton generation were maintained in the mosses to combat LTS; however, LTS inhibited the activity of glycolate oxidase. As predicted, N supply increased the sensitivity of the mosses to LTS, resulting in greater damage to PSII and a sharper decrease in C/N assimilation. After the recovery period, the performance of PSII and C/N metabolism, which were inhibited by LTS increased significantly, and were generally higher than those of control samples not exposed to LTS, suggesting overcompensation effects; however, N application reduced the extent of compensation effects. Both C and N metabolism exhibited stronger compensation effects in H. plumaeforme than in P. cirratum subsp. fuscatum. The

  8. Universe unveiled the cosmos in my bubble bath

    CERN Document Server

    Vishveshwara, C V

    2015-01-01

    The bubbles were swirling all around me, massaging my body. As I luxuriated in this fantastic bath, I gasped realizing that those bubbles carried with them miniature galaxies bringing the entire Cosmos into my bathtub... Alfie is back. And so are George and other characters from the author’s previous book Einstein’s Enigma or Black Holes in My Bubble Bath. While the present book, Universe Unveiled - The Cosmos in My Bubble Bath, is completely independent, its storyline can be considered a sequel to the previous one. The scientific content spanning ancient world models to the most recent mysteries of cosmology is presented in an entirely nontechnical and descriptive style through the discussions between Alfie, the enlightened learner, and George, professor of astrophysics. Fantasies, based on these discussions that cover the scientific facts, are created by the magical bubble baths taken by Alfie. Universe Unveiled blends accurate science with philosophy, drama, humour, and fantasy to create an exciting co...

  9. Understanding the interplay of carbon and nitrogen supply for ectoines production and metabolic overflow in high density cultures of Chromohalobacter salexigens.

    Science.gov (United States)

    Salar-García, María J; Bernal, Vicente; Pastor, José M; Salvador, Manuel; Argandoña, Montserrat; Nieto, Joaquín J; Vargas, Carmen; Cánovas, Manuel

    2017-02-08

    The halophilic bacterium Chromohalobacter salexigens has been proposed as promising cell factory for the production of the compatible solutes ectoine and hydroxyectoine. This bacterium has evolved metabolic adaptations to efficiently grow under high salt concentrations by accumulating ectoines as compatible solutes. However, metabolic overflow, which is a major drawback for the efficient conversion of biological feedstocks, occurs as a result of metabolic unbalances during growth and ectoines production. Optimal production of ectoines is conditioned by the interplay of carbon and nitrogen metabolisms. In this work, we set out to determine how nitrogen supply affects the production of ectoines. Chromohalobacter salexigens was challenged to grow in media with unbalanced carbon/nitrogen ratio. In C. salexigens, overflow metabolism and ectoines production are a function of medium composition. At low ammonium conditions, the growth rate decreased importantly, up to 80%. Shifts in overflow metabolism were observed when changing the C/N ratio in the culture medium. 13 C-NMR analysis of ectoines labelling revealed a high metabolic rigidity, with almost constant flux ratios in all conditions assayed. Unbalanced C/N ratio led to pyruvate accumulation, especially upon N-limitation. Analysis of an ect - mutant demonstrated the link between metabolic overflow and ectoine biosynthesis. Under non ectoine synthesizing conditions, glucose uptake and metabolic overflow decreased importantly. Finally, in fed-batch cultures, biomass yield was affected by the feeding scheme chosen. High growth (up to 42.4 g L -1 ) and volumetric ectoine yields (up to 4.21 g L -1 ) were obtained by minimizing metabolite overflow and nutrient accumulation in high density cultures in a low nitrogen fed-batch culture. Moreover, the yield coefficient calculated for the transformation of glucose into biomass was 30% higher in fed-batch than in the batch culture, demonstrating that the metabolic

  10. Effect of carbon tetrachloride on glycogen metabolism in fasted and refed mice

    Energy Technology Data Exchange (ETDEWEB)

    Pushpendran, C K; Shenoy, B V; Eapen, J [Bhabha Atomic Research Centre, Bombay (India). Biochemistry and Food Technology Div.

    1977-11-01

    Hepatic glycogen was depleted rapidly in fasted mice treated with CCl/sub 4/. Glycogen breakdown was slow when CCl/sub 4/ 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 CCl/sub 4/ injection. The incorporation of glucose-U-/sup 14/C into glycogen was higher in mice which were refed before CCl/sub 4/ administration than in fasted mice treated with the hepatotoxin. The specific activity of lactate was higher in CCl/sub 4/ treated mice. The data suggested differences in glycogen metabolism of fasted and refed mice in response to CCl/sub 4/ treatment.

  11. Photosynthetic carbon metabolism in seagrasses C-labeling evidence for the c(3) pathway.

    Science.gov (United States)

    Andrews, T J; Abel, K M

    1979-04-01

    The delta(13)C values of several seagrasses were considerably less negative than those of terrestrial C(3) plants and tended toward those of terrestrial C(4) plants. However, for Thalassia hemprichii (Ehrenb.) Aschers and Halophila spinulosa (R. Br.) Aschers, phosphoglycerate and other C(3) cycle intermediates predominated among the early labeled products of photosynthesis in (14)C-labeled seawater (more than 90% at the earliest times) and the labeling pattern at longer times was brought about by the operation of the C(3) pathway. Malate and aspartate together accounted for only a minor fraction of the total fixed label at all times and the kinetic data of this labeling were not at all consistent with these compounds being early intermediates in seagrass photosynthesis. Pulse-chase (14)C-labeling studies further substantiated these conclusions. Significant labeling of photorespiratory intermediates was observed in all experiments. The kinetics of total fixation of label during some steady-state and pulse-chase experiments suggested that there may be an intermediate pool of inorganic carbon of variable size closely associated with the leaves, either externally or internally. Such a pool may be one cause for the C(4)-like carbon isotope ratios of seagrasses.

  12. 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

    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...... 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......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...

  13. 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

  14. C1 Metabolism in Corynebacterium glutamicum: an Endogenous Pathway for Oxidation of Methanol to Carbon Dioxide

    Science.gov (United States)

    Witthoff, Sabrina; Mühlroth, Alice

    2013-01-01

    Methanol is considered an interesting carbon source in “bio-based” microbial production processes. Since Corynebacterium glutamicum is an important host in industrial biotechnology, in particular for amino acid production, we performed studies of the response of this organism to methanol. The C. glutamicum wild type was able to convert 13C-labeled methanol to 13CO2. Analysis of global gene expression in the presence of methanol revealed several genes of ethanol catabolism to be upregulated, indicating that some of the corresponding enzymes are involved in methanol oxidation. Indeed, a mutant lacking the alcohol dehydrogenase gene adhA showed a 62% reduced methanol consumption rate, indicating that AdhA is mainly responsible for methanol oxidation to formaldehyde. Further studies revealed that oxidation of formaldehyde to formate is catalyzed predominantly by two enzymes, the acetaldehyde dehydrogenase Ald and the mycothiol-dependent formaldehyde dehydrogenase AdhE. The Δald ΔadhE and Δald ΔmshC deletion mutants were severely impaired in their ability to oxidize formaldehyde, but residual methanol oxidation to CO2 was still possible. The oxidation of formate to CO2 is catalyzed by the formate dehydrogenase FdhF, recently identified by us. Similar to the case with ethanol, methanol catabolism is subject to carbon catabolite repression in the presence of glucose and is dependent on the transcriptional regulator RamA, which was previously shown to be essential for expression of adhA and ald. In conclusion, we were able to show that C. glutamicum possesses an endogenous pathway for methanol oxidation to CO2 and to identify the enzymes and a transcriptional regulator involved in this pathway. PMID:24014532

  15. 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

  16. Transcriptional regulation of respiration in yeast metabolizing differently repressive carbon substrates.

    Science.gov (United States)

    Fendt, Sarah-Maria; Sauer, Uwe

    2010-02-18

    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. 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. 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 for respiration.

  17. Novel Approaches to Investigate One-Carbon Metabolism and Related B-Vitamins in Blood Pressure

    Science.gov (United States)

    McMahon, Amy; McNulty, Helene; Hughes, Catherine F.; Strain, J. J.; Ward, Mary

    2016-01-01

    Hypertension, a major risk factor for heart disease and stroke, is the world’s leading cause of preventable, premature death. A common polymorphism (677C→T) in the gene encoding the folate metabolizing enzyme methylenetetrahydrofolate reductase (MTHFR) is associated with increased blood pressure, and there is accumulating evidence demonstrating that this phenotype can be modulated, specifically in individuals with the MTHFR 677TT genotype, by the B-vitamin riboflavin, an essential co-factor for MTHFR. The underlying mechanism that links this polymorphism, and the related gene-nutrient interaction, with hypertension is currently unknown. Previous research has shown that 5-methyltetrahydrofolate, the product of the reaction catalysed by MTHFR, appears to be a positive allosteric modulator of endothelial nitric oxide synthase (eNOS) and may thus increase the production of nitric oxide, a potent vasodilator. Blood pressure follows a circadian pattern, peaking shortly after wakening and falling during the night, a phenomenon known as ‘dipping’. Any deviation from this pattern, which can only be identified using ambulatory blood pressure monitoring (ABPM), has been associated with increased cardiovascular disease (CVD) risk. This review will consider the evidence linking this polymorphism and novel gene-nutrient interaction with hypertension and the potential mechanisms that might be involved. The role of ABPM in B-vitamin research and in nutrition research generally will also be reviewed. PMID:27845713

  18. Novel Approaches to Investigate One-Carbon Metabolism and Related B-Vitamins in Blood Pressure

    Directory of Open Access Journals (Sweden)

    Amy McMahon

    2016-11-01

    Full Text Available Hypertension, a major risk factor for heart disease and stroke, is the world’s leading cause of preventable, premature death. A common polymorphism (677C→T in the gene encoding the folate metabolizing enzyme methylenetetrahydrofolate reductase (MTHFR is associated with increased blood pressure, and there is accumulating evidence demonstrating that this phenotype can be modulated, specifically in individuals with the MTHFR 677TT genotype, by the B-vitamin riboflavin, an essential co-factor for MTHFR. The underlying mechanism that links this polymorphism, and the related gene-nutrient interaction, with hypertension is currently unknown. Previous research has shown that 5-methyltetrahydrofolate, the product of the reaction catalysed by MTHFR, appears to be a positive allosteric modulator of endothelial nitric oxide synthase (eNOS and may thus increase the production of nitric oxide, a potent vasodilator. Blood pressure follows a circadian pattern, peaking shortly after wakening and falling during the night, a phenomenon known as ‘dipping’. Any deviation from this pattern, which can only be identified using ambulatory blood pressure monitoring (ABPM, has been associated with increased cardiovascular disease (CVD risk. This review will consider the evidence linking this polymorphism and novel gene-nutrient interaction with hypertension and the potential mechanisms that might be involved. The role of ABPM in B-vitamin research and in nutrition research generally will also be reviewed.

  19. 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.

  20. 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.

  1. Nonstructural leaf carbohydrate 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

    2013-03-01

    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. We report analysis of foliar nonstructural carbohydrates (NSCs) and associated physiology from a previous experiment where earlier drought-induced mortality of Pinus edulis at elevated temperatures was associated with greater cumulative respiration. Here, we predicted faster NSC decline for warmed trees than for ambient-temperature trees. Foliar NSC in droughted trees declined by 30% through mortality and was lower than in watered controls. NSC decline resulted primarily from decreased sugar concentrations. Starch initially declined, and then increased above pre-drought concentrations before mortality. Although temperature did not affect NSC and sugar, starch concentrations ceased declining and increased earlier with higher temperatures. Reduced foliar NSC during lethal drought indicates a carbon metabolism role in mortality mechanism. Although carbohydrates were not completely exhausted at mortality, temperature differences in starch accumulation timing suggest that carbon metabolism changes are associated with time to death. Drought mortality appears to be related to temperature-dependent carbon dynamics concurrent with increasing hydraulic stress in P. edulis and potentially other similar species. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  2. γ-Aminobutyric acid transaminase deficiency impairs central carbon metabolism and leads to cell wall defects during salt stress in Arabidopsis roots.

    Science.gov (United States)

    Renault, Hugues; El Amrani, Abdelhak; Berger, Adeline; Mouille, Grégory; Soubigou-Taconnat, Ludivine; Bouchereau, Alain; Deleu, Carole

    2013-05-01

    Environmental constraints challenge cell homeostasis and thus require a tight regulation of metabolic activity. We have previously reported that the γ-aminobutyric acid (GABA) metabolism is crucial for Arabidopsis salt tolerance as revealed by the NaCl hypersensitivity of the GABA transaminase (GABA-T, At3g22200) gaba-t/pop2-1 mutant. In this study, we demonstrate that GABA-T deficiency during salt stress causes root and hypocotyl developmental defects and alterations of cell wall composition. A comparative genome-wide transcriptional analysis revealed that expression levels of genes involved in carbon metabolism, particularly sucrose and starch catabolism, were found to increase upon the loss of GABA-T function under salt stress conditions. Consistent with the altered mutant cell wall composition, a number of cell wall-related genes were also found differentially expressed. A targeted quantitative analysis of primary metabolites revealed that glutamate (GABA precursor) accumulated while succinate (the final product of GABA metabolism) significantly decreased in mutant roots after 1 d of NaCl treatment. Furthermore, sugar concentration was twofold reduced in gaba-t/pop2-1 mutant roots compared with wild type. Together, our results provide strong evidence that GABA metabolism is a major route for succinate production in roots and identify GABA as a major player of central carbon adjustment during salt stress. © 2012 Blackwell Publishing Ltd.

  3. Fungi, bacteria and soil pH: the oxalate-carbonate pathway as a model for metabolic interaction.

    Science.gov (United States)

    Martin, Gaëtan; Guggiari, Matteo; Bravo, Daniel; Zopfi, Jakob; Cailleau, Guillaume; Aragno, Michel; Job, Daniel; Verrecchia, Eric; Junier, Pilar

    2012-11-01

    The oxalate-carbonate pathway involves the oxidation of calcium oxalate to low-magnesium calcite and represents a potential long-term terrestrial sink for atmospheric CO(2). In this pathway, bacterial oxalate degradation is associated with a strong local alkalinization and subsequent carbonate precipitation. In order to test whether this process occurs in soil, the role of bacteria, fungi and calcium oxalate amendments was studied using microcosms. In a model system with sterile soil amended with laboratory cultures of oxalotrophic bacteria and fungi, the addition of calcium oxalate induced a distinct pH shift and led to the final precipitation of calcite. However, the simultaneous presence of bacteria and fungi was essential to drive this pH shift. Growth of both oxalotrophic bacteria and fungi was confirmed by qPCR on the frc (oxalotrophic bacteria) and 16S rRNA genes, and the quantification of ergosterol (active fungal biomass) respectively. The experiment was replicated in microcosms with non-sterilized soil. In this case, the bacterial and fungal contribution to oxalate degradation was evaluated by treatments with specific biocides (cycloheximide and bronopol). Results showed that the autochthonous microflora oxidized calcium oxalate and induced a significant soil alkalinization. Moreover, data confirmed the results from the model soil showing that bacteria are essentially responsible for the pH shift, but require the presence of fungi for their oxalotrophic activity. The combined results highlight that the interaction between bacteria and fungi is essential to drive metabolic processes in complex environments such as soil. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

  4. 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.

  5. Increased iron availability resulting from increased CO2 enhances carbon and nitrogen metabolism in the economical marine red macroalga Pyropia haitanensis (Rhodophyta).

    Science.gov (United States)

    Chen, Binbin; Zou, Dinghui; Yang, Yufeng

    2017-04-01

    Ocean acidification caused by rising CO 2 is predicted to increase the concentrations of dissolved species of Fe(II) and Fe(III), leading to the enhanced photosynthetic carbon sequestration in some algal species. In this study, the carbon and nitrogen metabolism in responses to increased iron availability under two CO 2 levels (390 μL L -1 and 1000 μL L -1 ), were investigated in the maricultivated macroalga Pyropia haitanensis (Rhodophyta). The results showed that, elevated CO 2 increased soluble carbonhydrate (SC) contents, resulting from enhanced photosynthesis and photosynthetic pigment synthesis in this algae, but declined its soluble protein (SP) contents, resulting in increased ratio of SC/SP. This enhanced photosynthesis performance and carbon accumulation was more significant under iron enrichment condition in seawater, with higher iron uptake rate at high CO 2 level. As a key essential biogenic element for algae, Fe-replete functionally contributed to P. haitanensis photosynthesis. Increased SC fundamentally provided carbon skeletons for nitrogen assimilation. The significant increase of carbon and nitrogen assimilation finally contributed to enhanced growth in this alga. This was also intuitively reflected by respiration that provided energy for cellular metabolism and algal growth. We propose that, in the predicted scenario of rising atmospheric CO 2 , P. haitanensis is capable to adjust its physiology by increasing its carbon and nitrogen metabolism to acclimate the acidified seawater, at the background of global climate change and simultaneously increased iron concentration due to decreased pH levels. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. ;Every dogma has its day': a personal look at carbon metabolism in photosynthetic bacteria.

    Science.gov (United States)

    Ormerod, John

    2003-01-01

    Dogmas are unscientific. What is perhaps the greatest biological dogma of all time, the 'unity of biochemistry' is, in the main, still having its day. According to present knowledge, the exceptions to this dogma are mere details when seen in relation to the biosystem as a whole. Nevertheless the exceptions are scientifically interesting and the understanding of them has led to a better comprehension of photosynthesis and ecology. Until the discovery of (14)C, photosynthetic CO(2) fixation was like a slightly opened black box. With (14)C in hand scientists mapped out the path of carbon in green plant photosynthesis in the course of a few years. The impressive reductive pentose phosphate cycle was almost immediately assumed to be universal in autotrophs, including anoxygenic phototrophs, in spite of the odd observation to the contrary. A new dogma was born and held the field for about two decades. Events began to turn when green sulfur bacteria were found to contain ferredoxin-coupled ketoacid-oxidoreductases. This led to the formulation of a novel CO(2)-fixing pathway, the reductive citric acid cycle, but its general acceptance required much work by many investigators. However, the ice had now been broken and after some years a third mechanism of CO(2) fixation was discovered, this time in Chloroflexus,and then a fourth in the same genus. One consequence of these discoveries is that it has become apparent that oxygen is an important factor that determines the kind of CO(2)-fixing mechanism an organism uses. With the prospect of the characterization of hordes of novel bacteria forecast by molecular ecologists we can expect further distinctive CO(2) fixation mechanisms to turn up.

  7. Maize source leaf adaptation to nitrogen deficiency affects not only nitrogen and carbon metabolism but also control of phosphate homeostasis.

    Science.gov (United States)

    Schlüter, Urte; Mascher, Martin; Colmsee, Christian; Scholz, Uwe; Bräutigam, Andrea; Fahnenstich, Holger; Sonnewald, Uwe

    2012-11-01

    Crop plant development is strongly dependent on the availability of nitrogen (N) in the soil and the efficiency of N utilization for biomass production and yield. However, knowledge about molecular responses to N deprivation derives mainly from the study of model species. In this article, the metabolic adaptation of source leaves to low N was analyzed in maize (Zea mays) seedlings by parallel measurements of transcriptome and metabolome profiling. Inbred lines A188 and B73 were cultivated under sufficient (15 mM) or limiting (0.15 mM) nitrate supply for up to 30 d. Limited availability of N caused strong shifts in the metabolite profile of leaves. The transcriptome was less affected by the N stress but showed strong genotype- and age-dependent patterns. N starvation initiated the selective down-regulation of processes involved in nitrate reduction and amino acid assimilation; ammonium assimilation-related transcripts, on the other hand, were not influenced. Carbon assimilation-related transcripts were characterized by high transcriptional coordination and general down-regulation under low-N conditions. N deprivation caused a slight accumulation of starch but also directed increased amounts of carbohydrates into the cell wall and secondary metabolites. The decrease in N availability also resulted in accumulation of phosphate and strong down-regulation of genes usually involved in phosphate starvation response, underlining the great importance of phosphate homeostasis control under stress conditions.

  8. 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.

  9. 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.

  10. 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.

  11. Unveiling the biotransformation mechanism of indole in a Cupriavidus sp. strain.

    Science.gov (United States)

    Qu, Yuanyuan; Ma, Qiao; Liu, Ziyan; Wang, Weiwei; Tang, Hongzhi; Zhou, Jiti; Xu, Ping

    2017-12-01

    Indole, an important signaling molecule as well as a typical N-heterocyclic aromatic pollutant, is widespread in nature. However, the biotransformation mechanisms of indole are still poorly studied. Here, we sought to unlock the genetic determinants of indole biotransformation in strain Cupriavidus sp. SHE based on genomics, proteomics and functional studies. A total of 177 proteins were notably altered (118 up- and 59 downregulated) in cells grown in indole mineral salt medium when compared with that in sodium citrate medium. RT-qPCR and gene knockout assays demonstrated that an indole oxygenase gene cluster was responsible for the indole upstream metabolism. A functional indole oxygenase, termed IndA, was identified in the cluster, and its catalytic efficiency was higher than those of previously reported indole oxidation enzymes. Furthermore, the indole downstream metabolism was found to proceed via the atypical CoA-thioester pathway rather than conventional gentisate and salicylate pathways. This unusual pathway was catalyzed by a conserved 2-aminobenzoyl-CoA gene cluster, among which the 2-aminobenzoyl-CoA ligase initiated anthranilate transformation. This study unveils the genetic determinants of indole biotransformation and will provide new insights into our understanding of indole biodegradation in natural environments and its functional studies. © 2017 John Wiley & Sons Ltd.

  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

    Directory of Open Access Journals (Sweden)

    Stéphanie Gérin

    2016-08-01

    Full Text Available 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

  13. Transcriptional control of monolignol biosynthesis in Pinus taeda: factors affecting monolignol ratios and carbon allocation in phenylpropanoid metabolism

    Science.gov (United States)

    Anterola, Aldwin M.; Jeon, Jae-Heung; Davin, Laurence B.; Lewis, Norman G.

    2002-01-01

    Transcriptional profiling of the phenylpropanoid pathway in Pinus taeda cell suspension cultures was carried out using quantitative real time PCR analyses of all known genes involved in the biosynthesis of the two monolignols, p-coumaryl and coniferyl alcohols (lignin/lignan precursors). When the cells were transferred to a medium containing 8% sucrose and 20 mm potassium iodide, the monolignol/phenylpropanoid pathway was induced, and transcript levels for phenylalanine ammonia lyase, cinnamate 4-hydroxylase, p-coumarate 3-hydroxylase, 4-coumarate:CoA ligase, caffeoyl-CoA O-methyltransferase, cinnamoyl-CoA reductase, and cinnamyl alcohol dehydrogenase were coordinately up-regulated. Provision of increasing levels of exogenously supplied Phe to saturating levels (40 mm) to the induction medium resulted in further up-regulation of their transcript levels in the P. taeda cell cultures; this in turn was accompanied by considerable increases in both p-coumaryl and coniferyl alcohol formation and excretion. By contrast, transcript levels for both cinnamate 4-hydroxylase and p-coumarate 3-hydroxylase were only slightly up-regulated. These data, when considered together with metabolic profiling results and genetic manipulation of various plant species, reveal that carbon allocation to the pathway and its differential distribution into the two monolignols is controlled by Phe supply and differential modulation of cinnamate 4-hydroxylase and p-coumarate 3-hydroxylase activities, respectively. The coordinated up-regulation of phenylalanine ammonia lyase, 4-coumarate:CoA ligase, caffeoyl-CoA O-methyltransferase, cinnamoyl-CoA reductase and cinnamyl alcohol dehydrogenase in the presence of increasing concentrations of Phe also indicates that these steps are not truly rate-limiting, because they are modulated according to metabolic demand. Finally, the transcript profile of a putative acid/ester O-methyltransferase, proposed as an alternative catalyst for O-methylation leading

  14. Metabolite Profile Analysis Reveals Functional Effects of 28-Day Vitamin B-6 Restriction on One-Carbon Metabolism and Tryptophan Catabolic Pathways in Healthy Men and Women123

    Science.gov (United States)

    da Silva, Vanessa R.; Rios-Avila, Luisa; Lamers, Yvonne; Ralat, Maria A.; Midttun, Øivind; Quinlivan, Eoin P.; Garrett, Timothy J.; Coats, Bonnie; Shankar, Meena N.; Percival, Susan S.; Chi, Yueh-Yun; Muller, Keith E.; Ueland, Per Magne; Stacpoole, Peter W.; Gregory, Jesse F.

    2013-01-01

    Suboptimal vitamin B-6 status, as reflected by low plasma pyridoxal 5′-phosphate (PLP) concentration, is associated with increased risk of vascular disease. PLP plays many roles, including in one-carbon metabolism for the acquisition and transfer of carbon units and in the transsulfuration pathway. PLP also serves as a coenzyme in the catabolism of tryptophan. We hypothesize that the pattern of these metabolites can provide information reflecting the functional impact of marginal vitamin B-6 deficiency. We report here the concentration of major constituents of one-carbon metabolic processes and the tryptophan catabolic pathway in plasma from 23 healthy men and women before and after a 28-d controlled dietary vitamin B-6 restriction (restriction yielded increased cystathionine (53% pre- and 76% postprandial; P restriction yielded lower kynurenic acid (22% pre- and 20% postprandial; P restriction and multilevel partial least squares-discriminant analysis supported this conclusion. Thus, plasma concentrations of creatine, cystathionine, kynurenic acid, and 3-hydroxykynurenine jointly reveal effects of vitamin B-6 restriction on the profiles of one-carbon and tryptophan metabolites and serve as biomarkers of functional effects of marginal vitamin B-6 deficiency. PMID:23966327

  15. Metabolite profile analysis reveals functional effects of 28-day vitamin B-6 restriction on one-carbon metabolism and tryptophan catabolic pathways in healthy men and women.

    Science.gov (United States)

    da Silva, Vanessa R; Rios-Avila, Luisa; Lamers, Yvonne; Ralat, Maria A; Midttun, Øivind; Quinlivan, Eoin P; Garrett, Timothy J; Coats, Bonnie; Shankar, Meena N; Percival, Susan S; Chi, Yueh-Yun; Muller, Keith E; Ueland, Per Magne; Stacpoole, Peter W; Gregory, Jesse F

    2013-11-01

    Suboptimal vitamin B-6 status, as reflected by low plasma pyridoxal 5'-phosphate (PLP) concentration, is associated with increased risk of vascular disease. PLP plays many roles, including in one-carbon metabolism for the acquisition and transfer of carbon units and in the transsulfuration pathway. PLP also serves as a coenzyme in the catabolism of tryptophan. We hypothesize that the pattern of these metabolites can provide information reflecting the functional impact of marginal vitamin B-6 deficiency. We report here the concentration of major constituents of one-carbon metabolic processes and the tryptophan catabolic pathway in plasma from 23 healthy men and women before and after a 28-d controlled dietary vitamin B-6 restriction (restriction yielded increased cystathionine (53% pre- and 76% postprandial; P restriction yielded lower kynurenic acid (22% pre- and 20% postprandial; P restriction and multilevel partial least squares-discriminant analysis supported this conclusion. Thus, plasma concentrations of creatine, cystathionine, kynurenic acid, and 3-hydroxykynurenine jointly reveal effects of vitamin B-6 restriction on the profiles of one-carbon and tryptophan metabolites and serve as biomarkers of functional effects of marginal vitamin B-6 deficiency.

  16. Carbon monoxide as a metabolic energy source for extremely halophilic microbes: implications for microbial activity in Mars regolith.

    Science.gov (United States)

    King, Gary M

    2015-04-07

    Carbon monoxide occurs at relatively high concentrations (≥800 parts per million) in Mars' atmosphere, where it represents a potentially significant energy source that could fuel metabolism by a localized putative surface or near-surface microbiota. However, the plausibility of CO oxidation under conditions relevant for Mars in its past or at present has not been evaluated. Results from diverse terrestrial brines and saline soils provide the first documentation, to our knowledge, of active CO uptake at water potentials (-41 MPa to -117 MPa) that might occur in putative brines at recurrent slope lineae (RSL) on Mars. Results from two extremely halophilic isolates complement the field observations. Halorubrum str. BV1, isolated from the Bonneville Salt Flats, Utah (to our knowledge, the first documented extremely halophilic CO-oxidizing member of the Euryarchaeota), consumed CO in a salt-saturated medium with a water potential of -39.6 MPa; activity was reduced by only 28% relative to activity at its optimum water potential of -11 MPa. A proteobacterial isolate from hypersaline Mono Lake, California, Alkalilimnicola ehrlichii MLHE-1, also oxidized CO at low water potentials (-19 MPa), at temperatures within ranges reported for RSL, and under oxic, suboxic (0.2% oxygen), and anoxic conditions (oxygen-free with nitrate). MLHE-1 was unaffected by magnesium perchlorate or low atmospheric pressure (10 mbar). These results collectively establish the potential for microbial CO oxidation under conditions that might obtain at local scales (e.g., RSL) on contemporary Mars and at larger spatial scales earlier in Mars' history.

  17. Analysis of the energy metabolism of urban socioeconomic sectors and the associated carbon footprints: Model development and a case study for Beijing

    International Nuclear Information System (INIS)

    Zhang, Yan; Zheng, Hongmei; Fath, Brian D.

    2014-01-01

    Cities consume 80% of the world's energy; therefore, analyzing urban energy metabolism and the resulting carbon footprint provides basic data for formulating target carbon emission reductions. While energy metabolism includes both direct and indirect consumptions among sectors, few researchers have studied indirect consumption due to a lack of data. In this study, we used input–output analysis to calculate the energy flows among directly linked sectors. Building on this, we used ecological network analysis to develop a model of urban energy flows and also account for energy consumption embodied by the flows among indirectly linked sectors (represented numerically as paths with a length of 2 or more). To illustrate the model, monetary input–output tables for Beijing from 2000 to 2010 were analyzed to determine the embodied energy consumption and associated carbon footprints of these sectors. This analysis reveals the environmental pressure based on the source (energy consumption) and sink (carbon footprint) values. Indirect consumption was Beijing's primary form, and the carbon footprint therefore resulted mainly from indirect consumption (both accounting for ca. 60% of the total, though with considerable variation among sectors). To reduce emissions, the utilization efficiency of indirect consumption must improve. - Highlights: • We quantified the embodied energy transfers among Beijing's socioeconomic sectors. • We calculated the sectors' intensity of energy consumption and carbon footprint. • The indirect energy consumption was higher than the direct for all sectors. • The high-indirect-consumption sectors are at the end of industrial supply chains. • High-indirect-consumption sectors can improve upstream products energy efficiency

  18. Exposure to Glycolytic Carbon Sources Reveals a Novel Layer of Regulation for the MalT Regulon

    Directory of Open Access Journals (Sweden)

    Sylvia A. Reimann

    2011-01-01

    Full Text Available Bacteria adapt to changing environments by means of tightly coordinated regulatory circuits. The use of synthetic lethality, a genetic phenomenon in which the combination of two nonlethal mutations causes cell death, facilitates identification and study of such circuitry. In this study, we show that the E. coli ompR malTcon double mutant exhibits a synthetic lethal phenotype that is environmentally conditional. MalTcon, the constitutively active form of the maltose system regulator MalT, causes elevated expression of the outer membrane porin LamB, which leads to death in the absence of the osmoregulator OmpR. However, the presence and metabolism of glycolytic carbon sources, such as sorbitol, promotes viability and unveils a novel layer of regulation within the complex circuitry that controls maltose transport and metabolism.

  19. 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.

  20. Light-dark (12:12) cycle of carbon and nitrogen metabolism in Crocosphaera watsonii WH8501: relation to the cell cycle.

    Science.gov (United States)

    Dron, Anthony; Rabouille, Sophie; Claquin, Pascal; Le Roy, Bertrand; Talec, Amélie; Sciandra, Antoine

    2012-04-01

    This study provides with original data sets on the physiology of the unicellular diazotrophic cyanobacterium Crocosphaera watsonii WH8501, maintained in continuous culture in conditions of obligate diazotrophy. Cultures were exposed to a 12:12 light-dark regime, representative of what they experience in nature and where growth is expected to be balanced. Nitrogen and carbon metabolism were monitored at high frequency and their dynamics was compared with the cell cycle. Results reveal a daily cycle in the physiological and biochemical parameters, tightly constrained by the timely decoupled processes of N(2) fixation and carbon acquisition. The cell division rate increased concomitantly to carbon accumulation and peaked 6 h into the light. The carbon content reached a maximum at the end of the light phase. N(2) fixation occurred mostly during the dark period and peaked between 9 and 10 h into the night, while DNA synthesis, reflected by DNA fluorescence, increased until the end of the night. Consequently, cells in G1- and S-phases present a marked decrease in their C:N ratio. Nitrogen acquisition through N(2) fixation exceeded 1.3- to 3-fold the nitrogen requirements for growth, suggesting that important amounts of nitrogen are excreted even under conditions supposed to favour balanced, carbon and nitrogen acquisitions. © 2011 Society for Applied Microbiology and Blackwell Publishing Ltd.

  1. Pathways of carbon and energy metabolism of the epibiotic community associated with the deep-sea hydrothermal vent shrimp Rimicaris exoculata.

    Science.gov (United States)

    Hügler, Michael; Petersen, Jillian M; Dubilier, Nicole; Imhoff, Johannes F; Sievert, Stefan M

    2011-01-07

    The shrimp Rimicaris exoculata dominates the faunal biomass at many deep-sea hydrothermal vent sites at the Mid-Atlantic Ridge. In its enlarged gill chamber it harbors a specialized epibiotic bacterial community for which a nutritional role has been proposed. We analyzed specimens from the Snake Pit hydrothermal vent field on the Mid-Atlantic Ridge by complementing a 16S rRNA gene survey with the analysis of genes involved in carbon, sulfur and hydrogen metabolism. In addition to Epsilon- and Gammaproteobacteria, the epibiotic community unexpectedly also consists of Deltaproteobacteria of a single phylotype, closely related to the genus Desulfocapsa. The association of these phylogenetic groups with the shrimp was confirmed by fluorescence in situ hybridization. Based on functional gene analyses, we hypothesize that the Gamma- and Epsilonproteobacteria are capable of autotrophic growth by oxidizing reduced sulfur compounds, and that the Deltaproteobacteria are also involved in sulfur metabolism. In addition, the detection of proteobacterial hydrogenases indicates the potential for hydrogen oxidation in these communities. Interestingly, the frequency of these phylotypes in 16S rRNA gene clone libraries from the mouthparts differ from that of the inner lining of the gill chamber, indicating potential functional compartmentalization. Our data show the specific association of autotrophic bacteria with Rimicaris exoculata from the Snake Pit hydrothermal vent field, and suggest that autotrophic carbon fixation is contributing to the productivity of the epibiotic community with the reductive tricarboxylic acid cycle as one important carbon fixation pathway. This has not been considered in previous studies of carbon fixation and stable carbon isotope composition of the shrimp and its epibionts. Furthermore, the co-occurrence of sulfur-oxidizing and sulfur-reducing epibionts raises the possibility that both may be involved in the syntrophic exchange of sulfur compounds

  2. 'THE UNVEILED HEART' a teaching program in cardiovascular nuclear medicine

    International Nuclear Information System (INIS)

    Itti, Roland; Merabet, Yasmina; Roca, Ramona; Bontemps, Laurence; Itti, Emmanuel

    2004-01-01

    The functional investigation of cardiac diseases using nuclear techniques involves several variables, such as myocardial perfusion, cellular viability or mechanical contraction. The combined, topographical and quantitative assessment of these variables can characterize the functional state of the heart in terms of normal myocardium, ischemia, hibernation or necrosis. The teaching program, 'The Unveiled Heart', has been designed in order to help nuclear physicians or cardiologists approaching these concepts and their implications for diagnosis of coronary artery disease, optimization of therapeutic strategies and prognosis evaluation. Anatomical correlations with coronary angiographic results obtained during balloon occlusion at the time of coronary angioplasty demonstrate the complementary role of imaging techniques and highlight the patient to patient variability of risk areas. A sectorial model derived from a polar projection of the myocardium presents for each sector the probability of involvement of a given coronary artery

  3. Photonic integrated circuits unveil crisis-induced intermittency.

    Science.gov (United States)

    Karsaklian Dal Bosco, Andreas; Akizawa, Yasuhiro; Kanno, Kazutaka; Uchida, Atsushi; Harayama, Takahisa; Yoshimura, Kazuyuki

    2016-09-19

    We experimentally investigate an intermittent route to chaos in a photonic integrated circuit consisting of a semiconductor laser with time-delayed optical feedback from a short external cavity. The transition from a period-doubling dynamics to a fully-developed chaos reveals a stage intermittently exhibiting these two dynamics. We unveil the bifurcation mechanism underlying this route to chaos by using the Lang-Kobayashi model and demonstrate that the process is based on a phenomenon of attractor expansion initiated by a particular distribution of the local Lyapunov exponents. We emphasize on the crucial importance of the distribution of the steady-state solutions introduced by the time-delayed feedback on the existence of this intermittent dynamics.

  4. 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.

  5. Effect of vermicompost on some physiological attributes involved in carbon and nitrogen metabolism as well as nutrient status in leaves of tobacco (nicotiana tabacum L.)

    International Nuclear Information System (INIS)

    Qin, C.; Zheng, P.; Akram, N.A.

    2016-01-01

    A pot experiment was carried out to examine the influence of vermicompost application on some key enzymes and metabolites involved in carbon (C) and nitrogen (N) metabolism as well as nutrient status in the leaves of tobacco (Nicotiana tabacum L.). Two types of vermicompost with two application rates were used in this study. Regardless of application rate, both types of vermicompost significantly increased total N, phosphorus (P) and potassium (K) contents in the leaves. They also caused enhancements in contents of total soluble carbohydrates, reducing sugars, starch and total organic C as well as amylase and invertase activities involved in C metabolism, contents of soluble protein and nicotine in N metabolism in the leaves. With an increase in application rate, each vermicompost type had an increasing effect on almost all measured parameters except nitrate reductase activity. Regardless of vermicompost type, the high rate (50%) of application showed the best effects compared with controls. The effects of V1 type vermicompost were superior to those of V2 at the same application rate. Therefore, the above effects might appear to be dependent on both type and dose. Vermicompost could be considered as an effective organic matter for attaining improved plant nutrition as well as C and N metabolism. (author)

  6. Lisosan G, a powder of grain, does not interfere with the drug metabolizing enzymes and has a protective role on carbon tetrachloride-induced hepatotoxicity.

    Science.gov (United States)

    Longo, Vincenzo; Chirulli, Vera; Gervasi, Pier Giovanni; Nencioni, Simona; Pellegrini, Michela

    2007-08-01

    Lisosan G is a powder of grain registered as an alimentary integrator. The treatment of rats for 4 days with 0.5 g Lisosan G/kg had no effect on various drug metabolizing enzymes. Experiments in vitro showed that Lisosan G had radical scavenger activity. A confirmation of the antioxidative property of Lisosan G was also confirmed when it was administered in vivo to carbon tetrachloride (CCl(4))-intoxicated rats. The toxicity caused by CCl(4)-treatment of rats was restored to the control levels when the rats were given Lisosan G for 4 days before CCl(4). Lisosan G thus does not interfere with drug metabolizing system but has antioxidant properties and protects against CCl(4)-induced hepatotoxicity.

  7. Physical and Biological Controls on the Carbonate Chemistry of Coral Reef Waters: Effects of Metabolism, Wave Forcing, Sea Level, and Geomorphology

    Science.gov (United States)

    Falter, James L.; Lowe, Ryan J.; Zhang, Zhenlin; McCulloch, Malcolm

    2013-01-01

    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 pCO2, pH, and aragonite saturation state (Ωar) are primarily dependent on changes in net production and are relatively insensitive to changes in net calcification; however, net changes in pCO2, pH, and Ωar 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 pCO2 relative to offshore values should be modest for reef systems with narrow and/or deep lagoons. Thus, the long-term evolution of water column pCO2 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 pCO2. PMID:23326411

  8. Physical and biological controls on the carbonate chemistry of coral reef waters: effects of metabolism, wave forcing, sea level, and geomorphology.

    Science.gov (United States)

    Falter, James L; Lowe, Ryan J; Zhang, Zhenlin; McCulloch, Malcolm

    2013-01-01

    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).

  9. Carbon isotope composition of intermediates of the starch-malate sequence and level of the crassulacean acid metabolism in leaves of Kalanchoe blossfeldiana Tom Thumb.

    Science.gov (United States)

    Deleens, E; Garnier-Dardart, J; Queiroz, O

    1979-09-01

    Isotype analyses were performed on biochemical fractions isolated from leaves of Kalanchoe blossfeldiana Tom Thumb. during aging under long days or short days. Irrespective of the age or photoperiodic conditions, the intermediates of the starch-malate sequence (starch, phosphorylated compounds and organic acids) have a level of (13)C higher than that of soluble sugars, cellulose and hemicellulose. In short days, the activity of the crassulacean acid metabolism pathway is predominant as compared to that of C3 pathway: leaves accumulate organic acids, rich in (13)C. In long days, the activity of the crassulacean acid metabolism pathway increases as the leaves age, remaining, however, relatively low as compared to that of C3 pathway: leaves accumulate soluble sugars, poor in (13)C. After photoperiodic change (long days→short days), isotopic modifications of starch and organic acids suggest evidence for a lag phase in the establishment of the crassulacean acid metabolism pathway specific to short days. The relative proportions of carbon from a C3-origin (RuBPC acitivity as strong discriminating step, isotope discrimination in vivo=20‰) or C4-origin (PEPC activity as weak discriminating step, isotope discrimination in vivo=4‰) present in the biochemical fractions were calculated from their δ(13)C values. Under long days, 30 to 70% versus 80 to 100% under short days, of the carbon of the intermediates linked to the starch-malate sequence, or CAM pathway (starch, phosphorylated compounds and organic acids), have a C4-origin. Products connected to the C3 pathway (free sugars, cellulose, hemicellulose) have 0 to 50% of their carbon, arising from reuptake of the C4 from malate, under long days versus 30 to 70% under short days.

  10. 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.

  11. 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. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Analysis of carbon and nitrogen co-metabolism in yeast by ultrahigh-resolution mass spectrometry applying 13C- and 15N-labeled substrates simultaneously

    International Nuclear Information System (INIS)

    Blank, Lars M.; Desphande, Rahul R.; Schmid, Andreas; Hayen, Heiko

    2012-01-01

    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 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., 13 C and 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 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 13 C-labeled glucose and 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.)

  13. The catabolite repressor/activator, Cra, bridges a connection between carbon metabolism and host colonization in the plant drought resistance-promoting bacterium Pantoea alhagi LTYR-11Z.

    Science.gov (United States)

    Zhang, Lei; Li, Muhang; Li, Qiqi; Chen, Chaoqiong; Qu, Meng; Li, Mengyun; Wang, Yao; Shen, Xihui

    2018-04-27

    Efficient root colonization is a prerequisite for application of plant growth promoting (PGP) bacteria in improving health and yield of agricultural crops. We have recently identified an endophytic bacterium Pantoea alhagi LTYR-11Z with multiple PGP properties that effectively colonizes the root system of wheat and improves its growth and drought tolerance. To identify novel regulatory genes required for wheat colonization, we screened a LTYR-11Z transposon (Tn) insertion library and found cra to be a colonization-related gene. By using RNA-seq analysis, we found that transcriptional levels of an eps operon, the ydiV gene encoding an anti-FlhD 4 C 2 factor and the yedQ gene encoding an enzyme for synthesis of cyclic dimeric GMP (c-di-GMP) were significantly downregulated in the mutant Δ cra. Further studies demonstrated that Cra directly binds to the promoters of the eps operon, ydiV and yedQ and activates their expression, thus inhibiting motility and promoting exopolysaccharides (EPS) production and biofilm formation. Consistent with previous findings that Cra plays a role in transcriptional regulation in response to carbon source availability, the activating effects of Cra were much more pronounced when LTYR-11Z was grown within a gluconeogenic environment than when it was grown within a glycolytic environment. We further demonstrate that the ability of LTYR-11Z to colonize wheat roots is modulated by the availability of carbon sources. All together, these results uncover a novel strategy utilized by LTYR-11Z to achieve host colonization in response to carbon nutrition in the environment, in which Cra bridges a connection between carbon metabolism and colonization capacity of LTYR-11Z. IMPORTANCE Rapid and appropriate response to environmental signals is crucial for bacteria to adapt to competitive environments and to establish interactions with their hosts. Efficient colonization and persistence within the host is controlled by various regulatory factors that

  14. 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.

  15. The presence of carbon nanostructures in bakery products induces metabolic stress in human mesenchymal stem cells through CYP1A and p53 gene expression.

    Science.gov (United States)

    Al-Hadi, Ahmed M; Periasamy, Vaiyapuri Subbarayan; Athinarayanan, Jegan; Alshatwi, Ali A

    2016-01-01

    Ingredients commonly present in processed foods are excellent substrates for chemical reactions during modern thermal cooking or processing, which could possibly result in deteriorative carbonization changes mediated by a variety of thermal reactions. Spontaneous self-assembling complexation or polymerization of partially combusted lipids, proteins, and other food macromolecules with synthetic food additives during high temperature food processing or baking (200-250 °C) would result in the formation of carbon nanostructures (CNs). These unknown nanostructures may produce adverse physiological effects or potential health risks. The present work aimed to identify and characterize the nanostructures from the crusts of bread. Furthermore, a toxicological risk assessment of these nanostructures was conducted using human mesenchymal stem cells (hMSCs) as a model for cellular uptake and metabolic oxidative stress, with special reference to induced adipogenesis. CNs isolated from bread crusts were characterized using transmission electron microscopy. The in vitro risk assessment of the CNs was carried out in hMSCs using an MTT assay, cell morphological assessment, a reactive oxygen species assay, a mitochondrial trans-membrane potential assay, cell cycle progression assessment and gene expression analysis. Our results revealed that bread crusts contain CNs, which may form during the bread-making process. The in vitro results indicate that carbon nanostructures have moderately toxic effects in the hMSCs at a high dose (400 μg/mL). The mitochondrial trans-membrane potentials and intracellular ROS levels of the hMSCs were altered at this dose. The levels of the mRNA transcripts of metabolic stress-responsive genes such as CAT, GSR, GSTA4, CYP1A and p53 were significantly altered in response to CNs. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Characterization of phosphofructokinase activity in Mycobacterium tuberculosis reveals that a functional glycolytic carbon flow is necessary to limit the accumulation of toxic metabolic intermediates under hypoxia.

    Directory of Open Access Journals (Sweden)

    Wai Yee Phong

    Full Text Available Metabolic versatility has been increasingly recognized as a major virulence mechanism that enables Mycobacterium tuberculosis to persist in many microenvironments encountered in its host. Glucose is one of the most abundant carbon sources that is exploited by many pathogenic bacteria in the human host. M. tuberculosis has an intact glycolytic pathway that is highly conserved in all clinical isolates sequenced to date suggesting that glucose may represent a non-negligible source of carbon and energy for this pathogen in vivo. Fructose-6-phosphate phosphorylation represents the key-committing step in glycolysis and is catalyzed by a phosphofructokinase (PFK activity. Two genes, pfkA and pfkB have been annotated to encode putative PFK in M. tuberculosis. Here, we show that PFKA is the sole PFK enzyme in M. tuberculosis with no functional redundancy with PFKB. PFKA is required for growth on glucose as sole carbon source. In co-metabolism experiments, we report that disruption of the glycolytic pathway at the PFK step results in intracellular accumulation of sugar-phosphates that correlated with significant impairment of the cell viability. Concomitantly, we found that the presence of glucose is highly toxic for the long-term survival of hypoxic non-replicating mycobacteria, suggesting that accumulation of glucose-derived toxic metabolites does occur in the absence of sustained aerobic respiration. The culture medium traditionally used to study the physiology of hypoxic mycobacteria is supplemented with glucose. In this medium, M. tuberculosis can survive for only 7-10 days in a true non-replicating state before death is observed. By omitting glucose in the medium this period could be extended for up to at least 40 days without significant viability loss. Therefore, our study suggests that glycolysis leads to accumulation of glucose-derived toxic metabolites that limits long-term survival of hypoxic mycobacteria. Such toxic effect is exacerbated when

  17. 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 (P<0.001) higher (25-45%) in astronauts with ophthalmic changes than in those without such changes (1). These differences existed before, during, and after flight. Serum folate was lower (P<0.01) during flight in individuals with ophthalmic changes. Preflight serum concentrations of cystathionine and 2-methylcitric acid, and mean in-flight serum folate, were significantly (P<0.05) correlated with postflight changes in refraction (1). A follow-up study was conducted to evaluate a small number of known polymorphisms of enzymes 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.

  18. Principles of Carbon Catabolite Repression in the Rice Blast Fungus: Tps1, Nmr1-3, and a MATE–Family Pump Regulate Glucose Metabolism during Infection

    Science.gov (United States)

    Hartline, David; Quispe, Cristian F.; Madayiputhiya, Nandakumar; Wilson, Richard A.

    2012-01-01

    Understanding the genetic pathways that regulate how pathogenic fungi respond to their environment is paramount to developing effective mitigation strategies against disease. Carbon catabolite repression (CCR) is a global regulatory mechanism found in a wide range of microbial organisms that ensures the preferential utilization of glucose over less favourable carbon sources, but little is known about the components of CCR in filamentous fungi. Here we report three new mediators of CCR in the devastating rice blast fungus Magnaporthe oryzae: the sugar sensor Tps1, the Nmr1-3 inhibitor proteins, and the multidrug and toxin extrusion (MATE)–family pump, Mdt1. Using simple plate tests coupled with transcriptional analysis, we show that Tps1, in response to glucose-6-phosphate sensing, triggers CCR via the inactivation of Nmr1-3. In addition, by dissecting the CCR pathway using Agrobacterium tumefaciens-mediated mutagenesis, we also show that Mdt1 is an additional and previously unknown regulator of glucose metabolism. Mdt1 regulates glucose assimilation downstream of Tps1 and is necessary for nutrient utilization, sporulation, and pathogenicity. This is the first functional characterization of a MATE–family protein in filamentous fungi and the first description of a MATE protein in genetic regulation or plant pathogenicity. Perturbing CCR in Δtps1 and MDT1 disruption strains thus results in physiological defects that impact pathogenesis, possibly through the early expression of cell wall–degrading enzymes. Taken together, the importance of discovering three new regulators of carbon metabolism lies in understanding how M. oryzae and other pathogenic fungi respond to nutrient availability and control development during infection. PMID:22570632

  19. Traditional Islamic cities unveiled: the quest for urban design regularity

    Directory of Open Access Journals (Sweden)

    Jorge Correia

    2015-08-01

    Full Text Available Traditional Islamic cities have generally gathered orientalized gazes and perspectives, picking up from misconceptions and stereotypes that during the second half af the 19th century andwere perpectuated by colonialism. More recent scholarship has shed light on the urban organizationand composition of such tissues; most of them confined to old quarters or historical centres ofthriving contemporary cities within the Arab-Muslim world. In fact, one of the most striking featureshas been the unveiling of layered urban assemblages where exterior agents have somehowlaunched or interrupted an apparent islamicized continuum. Primarly, this paper wishes to search forexternal political factors that have designed regularly geometrized patterns in medium-sized Arabtowns. For that, two case studies from different geographies - Maghreb and the Near East - will bemorphologically analysed through updated urban surveys. Whereas Nablus (Palestine ows the urbanmatrix of its old town to its Roman past, in Azemmour’s medina (Morocco it is still possible to trackthe thin European early-modern colonial stratum. However, both cases show how regularity patternschallenge Western concepts of geometrical design to embrace levels of rationality related to tradionalIslamic urban forms, societal configurations and built environment. Urban morphology becomes afundamental tool for articulating the history with me processes of sedimentation and evolution in orderto read current urban prints and dynamics. Thus, the paper will also interpret alternative logics ofrational urban display in Azemmour and Nablus, linked to ways of living within the Islamic sphere.

  20. Tempo and mode of genomic mutations unveil human evolutionary history.

    Science.gov (United States)

    Hara, Yuichiro

    2015-01-01

    Mutations that have occurred in human genomes provide insight into various aspects of evolutionary history such as speciation events and degrees of natural selection. Comparing genome sequences between human and great apes or among humans is a feasible approach for inferring human evolutionary history. Recent advances in high-throughput or so-called 'next-generation' DNA sequencing technologies have enabled the sequencing of thousands of individual human genomes, as well as a variety of reference genomes of hominids, many of which are publicly available. These sequence data can help to unveil the detailed demographic history of the lineage leading to humans as well as the explosion of modern human population size in the last several thousand years. In addition, high-throughput sequencing illustrates the tempo and mode of de novo mutations, which are producing human genetic variation at this moment. Pedigree-based human genome sequencing has shown that mutation rates vary significantly across the human genome. These studies have also provided an improved timescale of human evolution, because the mutation rate estimated from pedigree analysis is half that estimated from traditional analyses based on molecular phylogeny. Because of the dramatic reduction in sequencing cost, sequencing on-demand samples designed for specific studies is now also becoming popular. To produce data of sufficient quality to meet the requirements of the study, it is necessary to set an explicit sequencing plan that includes the choice of sample collection methods, sequencing platforms, and number of sequence reads.

  1. Hidden temporal order unveiled in stock market volatility variance

    Directory of Open Access Journals (Sweden)

    Y. Shapira

    2011-06-01

    Full Text Available When analyzed by standard statistical methods, the time series of the daily return of financial indices appear to behave as Markov random series with no apparent temporal order or memory. This empirical result seems to be counter intuitive since investor are influenced by both short and long term past market behaviors. Consequently much effort has been devoted to unveil hidden temporal order in the market dynamics. Here we show that temporal order is hidden in the series of the variance of the stocks volatility. First we show that the correlation between the variances of the daily returns and means of segments of these time series is very large and thus cannot be the output of random series, unless it has some temporal order in it. Next we show that while the temporal order does not show in the series of the daily return, rather in the variation of the corresponding volatility series. More specifically, we found that the behavior of the shuffled time series is equivalent to that of a random time series, while that of the original time series have large deviations from the expected random behavior, which is the result of temporal structure. We found the same generic behavior in 10 different stock markets from 7 different countries. We also present analysis of specially constructed sequences in order to better understand the origin of the observed temporal order in the market sequences. Each sequence was constructed from segments with equal number of elements taken from algebraic distributions of three different slopes.

  2. Unveiling protein functions through the dynamics of the interaction network.

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    Irene Sendiña-Nadal

    Full Text Available Protein interaction networks have become a tool to study biological processes, either for predicting molecular functions or for designing proper new drugs to regulate the main biological interactions. Furthermore, such networks are known to be organized in sub-networks of proteins contributing to the same cellular function. However, the protein function prediction is not accurate and each protein has traditionally been assigned to only one function by the network formalism. By considering the network of the physical interactions between proteins of the yeast together with a manual and single functional classification scheme, we introduce a method able to reveal important information on protein function, at both micro- and macro-scale. In particular, the inspection of the properties of oscillatory dynamics on top of the protein interaction network leads to the identification of misclassification problems in protein function assignments, as well as to unveil correct identification of protein functions. We also demonstrate that our approach can give a network representation of the meta-organization of biological processes by unraveling the interactions between different functional classes.

  3. Fructose Alters Intermediary Metabolism of Glucose in Human Adipocytes and Diverts Glucose to Serine Oxidation in the One–Carbon Cycle Energy Producing Pathway

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    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.

  4. The Cytochrome P450-Mediated Metabolism Alternation of Four Effective Lignans From Schisandra chinensis in Carbon Tetrachloride-Intoxicated Rats and Patients With Advanced Hepatocellular Carcinoma.

    Science.gov (United States)

    Wu, Rongrong; Xiao, Zhiyong; Zhang, Xiaorui; Liu, Feng; Zhou, Wenxia; Zhang, Yongxiang

    2018-01-01

    It is highly valuable to study the pharmacokinetics of herbal components under the pathological condition of liver dysfunction for safe and rational use of herbal medicines. In this study, the pharmacokinetic profiles of four effective lignans from Schisandra chinensis (SC) , schisandrin, schisantherin A, deoxyshisandrin and γ-schisandrin, were investigated in carbon tetrachloride (CCl 4 )-intoxicated rats. The metabolism of the four lignans was also studied using microsomes from patients with advanced hepatocellular carcinoma. In situ intestinal and hepatic perfusions were conducted to clarify the contributions from impairments of gut and liver on the pharmacokinetics of the four schisandra lignans in CCl 4 -intoxicated rats. The metabolism in rat and human liver microsomes and transport in Caco-2 monolayer cell model were studied to reveal the key factors for the in vivo disposition of the four lignans. When SC alcoholic extract was orally administrated to CCl 4 -intoxicated rat for a short term (4 days), the pharmacokinetics of four active SC lignans was significantly changed while its hepatotherapeutic effect was not obviously observed. The plasma concentrations of the four schisandra lignans were dramatically elevated compared with the control. The Cmax, AUC and MRT were all increased or prolonged significantly while parameter CLz/F was obviously reduced in rat pretreated with CCl 4 . In hepatic perfusion study and liver microsomes incubation, it was found that the hepatic metabolism of the four lignans was markedly decreased mainly due to the activity reduction of multiple CYP450 isoenzymes involved the metabolism, which, eventually, might lead to the alternation of their pharmacokinetic profiles in CCl 4 -intoxicated rats or patients with advanced hepatocellular carcinoma. The pharmacokinetic studies of SC components in pathological situation of liver dysfunction are expected to provide useful data for rational and safe application of SC preparations in

  5. Action of Gibberellins on Growth and Metabolism of Arabidopsis Plants Associated with High Concentration of Carbon Dioxide1[W

    Science.gov (United States)

    Ribeiro, Dimas M.; Araújo, Wagner L.; Fernie, Alisdair R.; Schippers, Jos H.M.; Mueller-Roeber, Bernd

    2012-01-01

    Although the positive effect of elevated CO2 concentration [CO2] on plant growth is well known, it remains unclear whether global climate change will positively or negatively affect crop yields. In particular, relatively little is known about the role of hormone pathways in controlling the growth responses to elevated [CO2]. Here, we studied the impact of elevated [CO2] on plant biomass and metabolism in Arabidopsis (Arabidopsis thaliana) in relation to the availability of gibberellins (GAs). Inhibition of growth by the GA biosynthesis inhibitor paclobutrazol (PAC) at ambient [CO2] (350 µmol CO2 mol−1) was reverted by elevated [CO2] (750 µmol CO2 mol−1). Thus, we investigated the metabolic adjustment and modulation of gene expression in response to changes in growth of plants imposed by varying the GA regime in ambient and elevated [CO2]. In the presence of PAC (low-GA regime), the activities of enzymes involved in photosynthesis and inorganic nitrogen assimilation were markedly increased at elevated [CO2], whereas the activities of enzymes of organic acid metabolism were decreased. Under ambient [CO2], nitrate, amino acids, and protein accumulated upon PAC treatment; however, this was not the case when plants were grown at elevated [CO2]. These results suggest that only under ambient [CO2] is GA required for the integration of carbohydrate and nitrogen metabolism underlying optimal biomass determination. Our results have implications concerning the action of the Green Revolution genes in future environmental conditions. PMID:23090585

  6. Aerial and underwater carbon metabolism of a Zostera noltii seagrass bed in the Banc d'Arguin, Mauritania

    NARCIS (Netherlands)

    Clavier, Jacques; Chauvaud, Laurent; Carlier, Antoine; Amice, Erwan; van der Geest, Matthijs; Labrosse, Pierre; Diagne, Ahmed; Hilya, Christian

    Community respiration and primary production were measured in a dense intertidal Zostera noltii bed on the Banc d’Arguin, Mauritania (West Africa) under aerial and submerged conditions. Metabolism was studied in situ in dark and transparent benthic chambers. CO2 fluxes in the air were measured over

  7. Microevolution analysis of Bacillus coahuilensis unveils differences in phosphorus acquisition strategies and their regulation

    Directory of Open Access Journals (Sweden)

    Zulema eGómez-Lunar

    2016-02-01

    Full Text Available Bacterial genomes undergo numerous events of gene losses and gains that generate genome variability among strains of the same species (microevolution. Our aim was to compare the genomes and relevant phenotypes of three Bacillus coahuilensis strains from two oligotrophic hydrological systems in the Cuatro Ciénegas Basin (México, to unveil the environmental challenges that this species cope with, and the microevolutionary differences in these genotypes. Since the strains were isolated from a low P environment, we placed emphasis on the search of different phosphorus acquisition strategies. The three B. coahuilensis strains exhibited similar numbers of coding DNA sequences, of which 82% (2, 893 constituted the core genome, and 18% corresponded to accessory genes. Most of the genes in this last group were associated with mobile genetic elements or were annotated as hypothetical proteins. Ten percent of the pangenome consisted of strain-specific genes. Alignment of the three B. coahuilensis genomes indicated a high level of synteny and revealed the presence of several genomic islands. Unexpectedly, one of these islands contained genes that encode the 2-keto-3-deoxymannooctulosonic acid (Kdo biosynthesis enzymes, a feature associated to cell walls of Gram-negative bacteria. Some microevolutionary changes were clearly associated with mobile genetic elements. Our analysis revealed inconsistencies between phenotype and genotype, which we suggest result from the impossibility to map regulatory features to genome analysis. Experimental results revealed variability in the types and numbers of auxotrophies between the strains that could not consistently be explained by in silico metabolic models. Several intraspecific differences in preferences for carbohydrate and phosphorus utilization were observed. Regarding phosphorus recycling, scavenging, and storage, variations were found between the three genomes. The three strains exhibited differences regarding

  8. Carbonization

    Energy Technology Data Exchange (ETDEWEB)

    Hennebutte, H G; Goutal, E

    1921-07-04

    Materials such as coal, peat, or schist are subjected to a rising temperature in successive stages in apparatus in which the distillation products are withdrawn at each stage. For example in a three-stage process, the acid products of the first or low-temperature stage are fixed in a suitable reagent, the basic products from a second or higher-temperature stage are absorbed in an acid reagent, hydrocarbons being retained by solvents, while the third are subjected to a pyrogenation process carried out in a closed vessel. Wherein the material is subjected in stages to a rising temperature, the gasified products being withdrawn at each stage, and are prevented as far as possible from mixing with the carbonized products.

  9. Systemic distribution of single-walled carbon nanotubes in a novel model: alteration of biochemical parameters, metabolic functions, liver accumulation, and inflammation in vivo

    Directory of Open Access Journals (Sweden)

    Principi E

    2016-09-01

    Full Text Available Elisa Principi,1,* Rossana Girardello,2,* Antonino Bruno,1,* Isabella Manni,3 Elisabetta Gini,2 Arianna Pagani,1 Annalisa Grimaldi,2 Federico Ivaldi,4 Terenzio Congiu,5 Daniela De Stefano,1 Giulia Piaggio,3 Magda de Eguileor,2 Douglas M Noonan,1,2 Adriana Albini1 1Vascular Biology and Angiogenesis, Scientific and Technology Pole, IRCCS MultiMedica, Milano, 2Department of Biotechnology and Life Sciences, University of Insubria, Varese, 3Department of Research, Advanced Diagnosis and Innovation, Regina Elena National Cancer Institute, Rome, 4Department of Neuroscience, Ophthalmology and Genetics, University of Genoa, Genoa, 5Department of Surgical and Morphological Sciences, University of Insubria, Varese, Italy *These authors contributed equally to this work Abstract: 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

  10. Insight into Energy Conservation via Alternative Carbon Monoxide Metabolism in Carboxydothermus pertinax Revealed by Comparative Genome Analysis.

    Science.gov (United States)

    Fukuyama, Yuto; Omae, Kimiho; Yoneda, Yasuko; Yoshida, Takashi; Sako, Yoshihiko

    2018-05-04

    Carboxydothermus species are some of the most studied thermophilic carboxydotrophs. Their varied carboxydotrophic growth properties suggest distinct strategies for energy conservation via CO metabolism. In this study, we used comparative genome analysis of the genus Carboxydothermus to show variations in the CO dehydrogenase/energy-converting hydrogenase gene cluster, which is responsible for CO metabolism with H 2 production (hydrogenogenic CO metabolism). Indeed, ability or inability to produce H 2 with CO oxidation is explained by the presence or absence of this gene cluster in C. hydrogenoformans , C. islandicus , and C. ferrireducens Interestingly, despite its hydrogenogenic CO metabolism, C. pertinax lacks the Ni-CO dehydrogenase catalytic subunit (CooS-I) and its transcriptional regulator encoding genes in this gene cluster probably due to inversion. Transcriptional analysis in C. pertinax showed that the Ni-CO dehydrogenase gene ( cooS-II ) and distantly encoded energy-converting hydrogenase related genes were remarkably upregulated under 100% CO. In addition, when thiosulfate was available as a terminal electron acceptor under 100% CO, C. pertinax maximum cell density and maximum specific growth rate were 3.1-fold and 1.5-fold higher, respectively, than when thiosulfate was absent. The amount of H 2 produced was only 63% of the consumed CO, less than expected according to hydrogenogenic CO oxidation: CO + H 2 O → CO 2 + H 2 Accordingly, C. pertinax would couple CO oxidation by Ni-CO dehydrogenase-II with simultaneous reduction of not only H 2 O but thiosulfate when grown under 100% CO. IMPORTANCE Anaerobic hydrogenogenic carboxydotrophs are thought to fill a vital niche with scavenging potentially toxic CO and producing H 2 as available energy source for thermophilic microbes. This hydrogenogenic carboxydotrophy relies on a Ni-CO dehydrogenase/energy-converting hydrogenase gene cluster. This feature is thought to be as common to these organisms. However

  11. Called to respond: The potential of unveiling hiddens

    Directory of Open Access Journals (Sweden)

    Alison L Black

    2014-12-01

    Full Text Available Interested in exploring how personal stories and aesthetic modes of representing experiences can nudge open academic and educational spaces, this article/collection of particles seeks to document our encounters of being affected and called to respond to things the other has written and represented. As a way of engaging with questions about what research and research data might be and become, our attention has been drawn to stories and images from our lives that we have not shaken off – and to how, as we have opened these to the other, making once private moments public, our hiddens have morphed tenderly into a shared knowing and being. As we have acted on the call we have felt to respond we have found ourselves entering spaces of collaboration, communion, contemplation, and conversation – spaces illuminated by what we have not been able to – and cannot – set aside. Using visual and poetic materials we explore heartfelt and heartbroken aspects of our educational worlds and lives, to be present with each other and our (reemerging personal and professional meanings. We see the shared body (of work, of writing, of image that develops from the taking of brave steps and the risky slipping off of academic masks and language, as a manifestation of the trusted and nurturing spaces that can be generated through collaborative opportunities to gather together. These steps towards unveiling hiddens are producing in us and of us a friendship, fluency, and fluidity as we write new ways of becoming. In turn, we hope the uncovering and revealing of our dialogue in the public gathering of this journal might supports readers’ telling of their own life stories through what calls them to respond.

  12. 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.

  13. Peculiarities of one-carbon metabolism in the strict carnivorous cat and the role in feline hepatic lipidosis.

    Science.gov (United States)

    Verbrugghe, Adronie; Bakovic, Marica

    2013-07-19

    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.

  14. Heritable IUGR and adult metabolic syndrome are reversible and associated with alterations in the metabolome following dietary supplementation of 1-carbon intermediates.

    Science.gov (United States)

    Seferovic, Maxim D; Goodspeed, Danielle M; Chu, Derrick M; Krannich, Laura A; Gonzalez-Rodriguez, Pablo J; Cox, James E; Aagaard, Kjersti M

    2015-06-01

    Metabolic syndrome (MetS), following intrauterine growth restriction (IUGR), is epigenetically heritable. Recently, we abrogated the F2 adult phenotype with essential nutrient supplementation (ENS) of intermediates along the 1-carbon pathway. With the use of the same grandparental uterine artery ligation model, we profiled the F2 serum metabolome at weaning [postnatal day (d)21; n = 76] and adulthood (d160; n = 12) to test if MetS is preceded by alterations in the metabolome. Indicative of developmentally programmed MetS, adult F2, formerly IUGR rats, were obese (621 vs. 461 g; P metabolome at weaning (randomForest analysis; class error metabolome accompany heritable IUGR, precede adult-onset MetS, and are partially amenable to dietary intervention. © FASEB.

  15. Genetic polymorphisms in one-carbon metabolism: associations with CpG island methylator phenotype (CIMP) in colon cancer and the modifying effects of diet.

    Science.gov (United States)

    Curtin, Karen; Slattery, Martha L; Ulrich, Cornelia M; Bigler, Jeannette; Levin, Theodore R; Wolff, Roger K; Albertsen, Hans; Potter, John D; Samowitz, Wade S

    2007-08-01

    This study investigated associations between CpG island methylator phenotype (CIMP) colon cancer and genetic polymorphisms relevant to one-carbon metabolism and thus, potentially the provision of methyl groups and risk of colon cancer. Data from a large, population-based case-control study (916 incident colon cancer cases and 1,972 matched controls) were used. Candidate polymorphisms in methylenetetrahydrofolate reductase (MTHFR), thymidylate synthase (TS), transcobalamin II (TCNII), methionine synthase (MTR), reduced folate carrier (RFC), methylenetetrahydrofolate dehydrogenase 1 (MTHFD1), dihydrofolate reductase (DHFR) and alcohol dehydrogenase 3 (ADH3) were evaluated. CIMP- or CIMP+ phenotype was based on five CpG island markers: MINT1, MINT2, MINT31, p16 and MLH1. The influence of specific dietary factors (folate, methionine, vitamin B(12) and alcohol) on these associations was also analyzed. We hypothesized that polymorphisms involved in the provision of methyl groups would be associated with CIMP+ tumors (two or more of five markers methylated), potentially modified by diet. Few associations specific to CIMP+ tumors were observed overall, which does not support the hypothesis that the provision of methyl groups is important in defining a methylator phenotype. However, our data suggest that genetic polymorphisms in MTHFR 1,298A > C, interacting with diet, may be involved in the development of highly CpG-methylated colon cancers. AC and CC genotypes in conjunction with a high-risk dietary pattern (low folate and methionine intake and high alcohol use) were associated with CIMP+ (OR = 2.1, 95% CI = 1.3-3.4 versus AA/high risk; P-interaction = 0.03). These results provide only limited support for a role of polymorphisms in one-carbon metabolism in the etiology of CIMP colon cancer.

  16. Potential Links between Impaired One-Carbon Metabolism Due to Polymorphisms, Inadequate B-Vitamin Status, and the Development of Alzheimer’s Disease

    Directory of Open Access Journals (Sweden)

    Barbara Troesch

    2016-12-01

    Full Text Available Alzheimer’s disease (AD is the major cause of dementia and no preventive or effective treatment has been established to date. The etiology of AD is poorly understood, but genetic and environmental factors seem to play a role in its onset and progression. In particular, factors affecting the one-carbon metabolism (OCM are thought to be important and elevated homocysteine (Hcy levels, indicating impaired OCM, have been associated with AD. We aimed at evaluating the role of polymorphisms of key OCM enzymes in the etiology of AD, particularly when intakes of relevant B-vitamins are inadequate. Our review indicates that a range of compensatory mechanisms exist to maintain a metabolic balance. However, these become overwhelmed if the activity of more than one enzyme is reduced due to genetic factors or insufficient folate, riboflavin, vitamin B6 and/or vitamin B12 levels. Consequences include increased Hcy levels and reduced capacity to synthetize, methylate and repair DNA, and/or modulated neurotransmission. This seems to favor the development of hallmarks of AD particularly when combined with increased oxidative stress e.g., in apolipoprotein E (ApoE ε4 carriers. However, as these effects can be compensated at least partially by adequate intakes of B-vitamins, achieving optimal B-vitamin status for the general population should be a public health priority.

  17. Central and storage carbon metabolism of the brown alga Ectocarpus siliculosus: insights into the origin and evolution of storage carbohydrates in Eukaryotes.

    Science.gov (United States)

    Michel, Gurvan; Tonon, Thierry; Scornet, Delphine; Cock, J Mark; Kloareg, Bernard

    2010-10-01

    • Brown algae exhibit a unique carbon (C) storage metabolism. The photoassimilate D-fructose 6-phosphate is not used to produce sucrose but is converted into D-mannitol. These seaweeds also store C as β-1,3-glucan (laminarin), thus markedly departing from most living organisms, which use α-1,4-glucans (glycogen or starch). • Using a combination of bioinformatic and phylogenetic approaches, we identified the candidate genes for the enzymes involved in C storage in the genome of the brown alga Ectocarpus siliculosus and traced their evolutionary origins. • Ectocarpus possesses a complete set of enzymes for synthesis of mannitol, laminarin and trehalose. By contrast, the pathways for sucrose, starch and glycogen are completely absent. • The synthesis of β-1,3-glucans appears to be a very ancient eukaryotic pathway. Brown algae inherited the trehalose pathway from the red algal progenitor of phaeoplasts, while the mannitol pathway was acquired by lateral gene transfer from Actinobacteria. The starch metabolism of the red algal endosymbiont was entirely lost in the ancestor of Stramenopiles. In light of these novel findings we question the validity of the 'Chromalveolate hypothesis'.

  18. Assessment of changes in energy metabolism parameters provoked by carbon tetrachloride in Wistar rats and the protective effect of white grape juice

    Directory of Open Access Journals (Sweden)

    Tatiane Gabardo

    2015-01-01

    Full Text Available The objective of this study was to evaluate the effect of organic and conventional grape juices consumption on the behavior of rats and their neuroprotective effect on the activity of brain energy metabolism enzymes in different brain areas of adult rats on the experimental model of hepatic encephalopathy. Male Wistar rats (90-days-old were treated once a day with conventional or organic white grape juice by gavage for 14 days (7 μL/g. On the 15th day the rats received carbon tetrachloride (CCl4 in a single dose of 3.0 mL/kg. Cerebral cortex, hippocampus and cerebellum were dissected to measure the activity of creatine kinase (CK and pyruvate kinase (PK. No changes in feeding behavior were observed after the treatment with the grapes juices. However, there was an increase in grooming behavior in the open field test provoked by both juices. CCl4 inhibited CK activity in cerebral cortex and hippocampus of the rats and CCl4 also reduced PK activity in all brain structures studied. Furthermore, both white grape juices prevented the decrease in the activity of CK and PK. Therefore, we can suggest that organic and conventional white grape juices could restore the activity of enzymes with a central role in brain energy metabolism.

  19. Acetylome analysis reveals the involvement of lysine acetylation in photosynthesis and carbon metabolism in the model cyanobacterium Synechocystis sp. PCC 6803.

    Science.gov (United States)

    Mo, Ran; Yang, Mingkun; Chen, Zhuo; Cheng, Zhongyi; Yi, Xingling; Li, Chongyang; He, Chenliu; Xiong, Qian; Chen, Hui; Wang, Qiang; Ge, Feng

    2015-02-06

    Cyanobacteria are the oldest known life form inhabiting Earth and the only prokaryotes capable of performing oxygenic photosynthesis. Synechocystis sp. PCC 6803 (Synechocystis) is a model cyanobacterium used extensively in research on photosynthesis and environmental adaptation. Posttranslational protein modification by lysine acetylation plays a critical regulatory role in both eukaryotes and prokaryotes; however, its extent and function in cyanobacteria remain unexplored. Herein, we performed a global acetylome analysis on Synechocystis through peptide prefractionation, antibody enrichment, and high accuracy LC-MS/MS analysis; identified 776 acetylation sites on 513 acetylated proteins; and functionally categorized them into an interaction map showing their involvement in various biological processes. Consistent with previous reports, a large fraction of the acetylation sites are present on proteins involved in cellular metabolism. Interestingly, for the first time, many proteins involved in photosynthesis, including the subunits of phycocyanin (CpcA, CpcB, CpcC, and CpcG) and allophycocyanin (ApcA, ApcB, ApcD, ApcE, and ApcF), were found to be lysine acetylated, suggesting that lysine acetylation may play regulatory roles in the photosynthesis process. Six identified acetylated proteins associated with photosynthesis and carbon metabolism were further validated by immunoprecipitation and Western blotting. Our data provide the first global survey of lysine acetylation in cyanobacteria and reveal previously unappreciated roles of lysine acetylation in the regulation of photosynthesis. The provided data set may serve as an important resource for the functional analysis of lysine acetylation in cyanobacteria and facilitate the elucidation of the entire metabolic networks and photosynthesis process in this model cyanobacterium.

  20. Non-toxic engineered carbon nanodiamond concentrations induce oxidative/nitrosative stress, imbalance of energy metabolism, and mitochondrial dysfunction in microglial and alveolar basal epithelial cells.

    Science.gov (United States)

    Fresta, Claudia G; Chakraborty, Aishik; Wijesinghe, Manjula B; Amorini, Angela M; Lazzarino, Giacomo; Lazzarino, Giuseppe; Tavazzi, Barbara; Lunte, Susan M; Caraci, Filippo; Dhar, Prajnaparamita; Caruso, Giuseppe

    2018-02-14

    Engineered nanoparticles are finding a wide spectrum of biomedical applications, including drug delivery and capacity to trigger cytotoxic phenomena, potentially useful against tumor cells. The full understanding of their biosafety and interactions with cell processes is mandatory. Using microglial (BV-2) and alveolar basal epithelial (A549) cells, in this study we determined the effects of engineered carbon nanodiamonds (ECNs) on cell viability, nitric oxide (NO) and reactive oxygen species (ROS) production, as well as on energy metabolism. Particularly, we initially measured decrease in cell viability as a function of increasing ECNs doses, finding similar cytotoxic ECN effects in the two cell lines. Subsequently, using apparently non-cytotoxic ECN concentrations (2 µg/mL causing decrease in cell number < 5%) we determined NO and ROS production, and measured the concentrations of compounds related to energy metabolism, mitochondrial functions, oxido-reductive reactions, and antioxidant defences. We found that in both cell lines non-cytotoxic ECN concentrations increased NO and ROS production with sustained oxidative/nitrosative stress, and caused energy metabolism imbalance (decrease in high energy phosphates and nicotinic coenzymes) and mitochondrial malfunctioning (decrease in ATP/ADP ratio).These results underline the importance to deeply investigate the molecular and biochemical changes occurring upon the interaction of ECNs (and nanoparticles in general) with living cells, even at apparently non-toxic concentration. Since the use of ECNs in biomedical field is attracting increasing attention the complete evaluation of their biosafety, toxicity and/or possible side effects both in vitro and in vivo is mandatory before these highly promising tools might find the correct application.

  1. Vitamins B2 and B6 and Genetic Polymorphisms Related to One-Carbon Metabolism as Risk Factors for Gastric Adenocarcinoma in the European Prospective Investigation into Cancer and Nutrition

    NARCIS (Netherlands)

    Eussen, Simone J. P. M.; Vollset, Stein Emil; Hustad, Steinar; Midttun, Oivind; Meyer, Klaus; Fredriksen, Ase; Ueland, Per Magne; Jenab, Mazda; Slimani, Nadia; Ferrari, Pietro; Agudo, Antonio; Sala, Nuria; Capella, Gabriel; Del Giudice, Giuseppe; Palli, Domenico; Boeing, Heiner; Weikert, Cornelia; Bueno-de-Mesquita, H. Bas; Buechner, Frederike L.; Carneiro, Fatima; Berrino, Franco; Vineis, Paolo; Tumino, Rosario; Panico, Salvatore; Berglund, Goran; Manjer, Jonas; Stenling, Roger; Hallmans, Goeran; Martinez, Carmen; Arrizola, Larraitz; Barricarte, Aurelio; Navarro, Carmen; Rodriguez, Laudina; Bingham, Sheila; Linseisen, Jakob; Kaaks, Rudolf; Overvad, Kim; Tjonneland, Anne; Peeters, Petra H. M.; Numans, Mattijs E.; Clavel-Chapelon, Francoise; Boutron-Ruault, Marie-Christine; Morois, Sophie; Trichopoulou, Antonia; Lund, Eiliv; Plebani, Mario; Riboli, Elio; Gonzalez, Carlos A.

    B vitamins and polymorphisms in genes coding for enzymes involved in one-carbon metabolism may affect DNA synthesis and methylation and thereby be implicated in carcinogenesis. Previous data on vitamins B2 and B6 and genetic polymorphisms other than those involving MTHFR as risk factors for gastric

  2. Effects of nitrogen infiltration into plant tissue on the metabolism of carbon, with special reference to Themeda triandra Forssk

    Energy Technology Data Exchange (ETDEWEB)

    Amory, A M

    1983-01-01

    The infiltration of nitrate and ammonia into Themeda triandra and Zea mays leaf tissue influenced the carbon dioxide gas exchange characteristics: 1) the carbon dioxide compensation point increased, 2) the net photosynthetic rate was increased by the nitrate ion and decreased by the ammonium ion, and 3) dark respiration was unaffected. /sup 14/CO/sub 2/ assimilation and the partitioning of /sup 14/C by Themeda triandra leaves were influenced by the infiltration of both forms of nitrogen; the amino acid fraction changed in both composition and concentration. Nitrogen infiltration increased the activities of the following enzymes: aspartate amino-transferase, PEP carboxylase and RuBP carboxylase. Methionine sulphoximine (inhibitor of glutamate synthetase) increased the carbon dioxide compensation point and formate pool size. Infiltration of nitrate and ammonia enhanced the /sup 14/C uptake from labelled glycolate, glyoxylate and formate into the water soluble fraction of Themeda triandra leaves. The activities of RuBP carboxylase and RuBP oxygenase (to a greater extent) were increased by the addition of nitrate and ammonia in vitro.

  3. Elucidation of rice rhizosphere metagenome in relation to methane and nitrogen metabolism under elevated carbon dioxide and temperature using whole genome metagenomic approach.

    Science.gov (United States)

    Bhattacharyya, P; Roy, K S; Das, M; Ray, S; Balachandar, D; Karthikeyan, S; Nayak, A K; Mohapatra, T

    2016-01-15

    Carbon (C) and nitrogen (N) mineralization is one of the key processes of biogeochemical cycling in terrestrial ecosystem in general and rice ecology in particular. Rice rhizosphere is a rich niche of microbial diversity influenced by change in atmospheric temperature and concentration of carbon dioxide (CO2). Structural changes in microbial communities in rhizosphere influence the nutrient cycling. In the present study, the bacterial diversity and population dynamics were studied under ambient CO2 (a-CO2) and elevated CO2+temperature (e-CO2T) in lowland rice rhizosphere using whole genome metagenomic approach. The whole genome metagenomic sequence data of lowland rice exhibited the dominance of bacterial communities including Proteobacteria, Firmicutes, Acidobacteria, Actinobacteria and Planctomycetes. Interestingly, four genera related to methane production namely, Methanobacterium, Methanosphaera, Methanothermus and Methanothermococcus were absent in a-CO2 but noticed under e-CO2T. The acetoclastic pathway was found as the predominant pathway for methanogenesis, whereas, the serine pathway was found as the principal metabolic pathway for CH4 oxidation in lowland rice. The abundances of reads of enzymes in the acetoclastic methanogenesis pathway and serine pathways of methanotrophy were much higher in e-CO2T (328 and 182, respectively) as compared with a-CO2 (118 and 98, respectively). Rice rhizosphere showed higher structural diversities and functional activities in relation to N metabolism involving nitrogen fixation, assimilatory and dissimilatory nitrate reduction and denitrification under e-CO2T than that of a-CO2. Among the three pathways of N metabolism, dissimilarity pathways were predominant in lowland rice rhizosphere and more so under e-CO2T. Consequently, under e-CO2T, CH4 emission, microbial biomass nitrogen (MBN) and dehydrogenase activities were 45%, 20% and 35% higher than a-CO2, respectively. Holistically, a high bacterial diversity and

  4. The chitosan affects severely the carbon metabolism in mango (Mangifera indica L. cv. Palmer) fruit during storage.

    Science.gov (United States)

    Cosme Silva, Gláucia Michelle; Silva, Willian Batista; Medeiros, David B; Salvador, Acácio Rodrigues; Cordeiro, Maria Helena Menezes; da Silva, Natália Martins; Santana, Diederson Bortolini; Mizobutsi, Gisele Polete

    2017-12-15

    Mango is a highly perishable fruit with a short post-harvest time due to the intense metabolic activity after harvesting. In attempt to evaluate the effects of chitosan in mango fruits, it was treated with 0%, 1%, 2% or 3% of chitosan solutions, placed into plastic trays, and stored at room temperature. Changes in physical and chemical parameters were evaluated. Chitosan delayed the climacteric peak, water loss and firmness. Further, few changes in soluble solid content, titratable acidity, pH of the pulp as well as in sugar content and decreased starch degradation were observed. Altogether, our results suggest chitosan edible coating effectively prolongs the quality attributes, affecting basic mitochondrial respiration and starch degradation rate. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. A theoretical framework for whole-plant carbon assimilation efficiency based on metabolic scaling theory: a test case using Picea seedlings.

    Science.gov (United States)

    Wang, Zhiqiang; Ji, Mingfei; Deng, Jianming; Milne, Richard I; Ran, Jinzhi; Zhang, Qiang; Fan, Zhexuan; Zhang, Xiaowei; Li, Jiangtao; Huang, Heng; Cheng, Dongliang; Niklas, Karl J

    2015-06-01

    Simultaneous and accurate measurements of whole-plant instantaneous carbon-use efficiency (ICUE) and annual total carbon-use efficiency (TCUE) are difficult to make, especially for trees. One usually estimates ICUE based on the net photosynthetic rate or the assumed proportional relationship between growth efficiency and ICUE. However, thus far, protocols for easily estimating annual TCUE remain problematic. Here, we present a theoretical framework (based on the metabolic scaling theory) to predict whole-plant annual TCUE by directly measuring instantaneous net photosynthetic and respiratory rates. This framework makes four predictions, which were evaluated empirically using seedlings of nine Picea taxa: (i) the flux rates of CO(2) and energy will scale isometrically as a function of plant size, (ii) whole-plant net and gross photosynthetic rates and the net primary productivity will scale isometrically with respect to total leaf mass, (iii) these scaling relationships will be independent of ambient temperature and humidity fluctuations (as measured within an experimental chamber) regardless of the instantaneous net photosynthetic rate or dark respiratory rate, or overall growth rate and (iv) TCUE will scale isometrically with respect to instantaneous efficiency of carbon use (i.e., the latter can be used to predict the former) across diverse species. These predictions were experimentally verified. We also found that the ranking of the nine taxa based on net photosynthetic rates differed from ranking based on either ICUE or TCUE. In addition, the absolute values of ICUE and TCUE significantly differed among the nine taxa, with both ICUE and temperature-corrected ICUE being highest for Picea abies and lowest for Picea schrenkiana. Nevertheless, the data are consistent with the predictions of our general theoretical framework, which can be used to access annual carbon-use efficiency of different species at the level of an individual plant based on simple, direct

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1979-04-01

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

  7. Nasa Unveils Cosmic Images Book in Braille for Blind Readers

    Science.gov (United States)

    2008-01-01

    BALTIMORE - At a Tuesday ceremony at the National Federation of the Blind, NASA unveiled a new book that brings majestic images taken by its Great Observatories to the fingertips of the blind. "Touch the Invisible Sky" is a 60-page book with color images of nebulae, stars, galaxies and some of the telescopes that captured the original pictures. Each image is embossed with lines, bumps and other textures. These raised patterns translate colors, shapes and other intricate details of the cosmic objects, allowing visually impaired people to experience them. Braille and large-print descriptions accompany each of the book's 28 photographs, making the book's design accessible to readers of all visual abilities. Sample page Sample page The book contains spectacular images from the Hubble Space Telescope, Chandra X-ray Observatory, Spitzer Space Telescope and powerful ground-based telescopes. The celestial objects are presented as they appear through visible-light telescopes and different spectral regions invisible to the naked eye, from radio to infrared, visible, ultraviolet and X-ray light. The book introduces the concept of light and the spectrum and explains how the different observatories complement each others' findings. Readers take a cosmic journey beginning with images of the sun, and travel out into the galaxy to visit relics of exploding and dying stars, as well as the Whirlpool galaxy and colliding Antennae galaxies. People Who Read This Also Read... Chandra Data Reveal Rapidly Whirling Black Holes Jet Power and Black Hole Assortment Revealed in New Chandra Image Action Replay of Powerful Stellar Explosion Black Holes Are The Rhythm at The Heart of Galaxies "Touch the Invisible Sky" was written by astronomy educator and accessibility specialist Noreen Grice of You Can Do Astronomy LLC and the Museum of Science, Boston, with authors Simon Steel, an astronomer with the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., and Doris Daou, an astronomer

  8. Metabolomics to unveil and understand phenotypic diversity between pathogen populations.

    Directory of Open Access Journals (Sweden)

    Ruben t'Kindt

    Full Text Available Leishmaniasis is a debilitating disease caused by the parasite Leishmania. There is extensive clinical polymorphism, including variable responsiveness to treatment. We study Leishmania donovani parasites isolated from visceral leishmaniasis patients in Nepal that responded differently to antimonial treatment due to differing intrinsic drug sensitivity of the parasites. Here, we present a proof-of-principle study in which we applied a metabolomics pipeline specifically developed for L. donovani to characterize the global metabolic differences between antimonial-sensitive and antimonial-resistant L. donovani isolates. Clones of drug-sensitive and drug-resistant parasite isolates from clinical samples were cultured in vitro and harvested for metabolomics analysis. The relative abundance of 340 metabolites was determined by ZIC-HILIC chromatography coupled to LTQ-Orbitrap mass spectrometry. Our measurements cover approximately 20% of the predicted core metabolome of Leishmania and additionally detected a large number of lipids. Drug-sensitive and drug-resistant parasites showed distinct metabolic profiles, and unsupervised clustering and principal component analysis clearly distinguished the two phenotypes. For 100 metabolites, the detected intensity differed more than three-fold between the 2 phenotypes. Many of these were in specific areas of lipid metabolism, suggesting that the membrane composition of the drug-resistant parasites is extensively modified. Untargeted metabolomics has been applied on clinical Leishmania isolates to uncover major metabolic differences between drug-sensitive and drug-resistant isolates. The identified major differences provide novel insights into the mechanisms involved in resistance to antimonial drugs, and facilitate investigations using targeted approaches to unravel the key changes mediating drug resistance.

  9. Partitioning between primary and secondary metabolism of carbon allocated to roots in four maize genotypes under water deficit and its effects on productivity

    Directory of Open Access Journals (Sweden)

    Alyne Oliveira Lavinsky

    2015-10-01

    Full Text Available Plants may respond to drought by altering biomass allocation to shoots and roots or by changing the metabolic activities in these organs. To determine how drought changes the partitioning of carbon allocated to growth and secondary metabolism in maize roots and how it affects photosynthesis (A and productivity in maize, we evaluated leaf gas exchange, yield componentes, root morphology, and primary and secondary metabolites including total soluble sugars (TSS, starch (S, phenolics (PHE, and lignin (LIG. Data were collected from pot-grown plants of four maize genotypes: BRS 1010 and 2B710 (sensitive genotypes and DKB390 and BRS1055 (tolerant genotypes under two soil water tensions: field capacity (FC, − 18 kPa and water deficit (WD, − 138 kPa. WD was applied at the pre-flowering stage for 12 days and then the water supply was restored and maintained at optimum levels until the end of the cycle. For genotype BRS 1055 under FC, the greatest A did not result in greater grain biomass (DGB because the accumulated photoassimilates had already filled the cells, and thus the excessive TSS synthesized in leaves was allocated to roots in large amounts. However, the sharp decrease in A caused by WD imposition in this genotype did not affect the influx pressure of leaf TSS, which was due largely to conversion of primary metabolites to PHE compounds to increase the length of fine roots. In leaves of DKB390 under WD, both S and TSS were reduced, whereas PHE were increased to prevent excessive water loss and xylem cavitation. Under WD, both BRS1010 and 2B710 genotypes displayed reduced allocation of biomass to shoots and roots and LIG content in leaves, as well as lower A and DGB values. In BRS1010 this response was coupled to S decrease in leaves and TSS increase in roots, whereas in 2B710 there was a concomitant S increase in roots.

  10. Alterations in carbon and nitrogen metabolism induced by water deficit in the stems and leaves of Lupinus albus L.

    Science.gov (United States)

    Pinheiro, C; Chaves, M M; Ricardo, C P

    2001-05-01

    Water deficit (WD) in Lupinus albus L. brings about tissue-specific responses that are dependent on stress intensity. Carbohydrate metabolism is very sensitive to changes in plant water status. Six days from withholding water (DAW), sucrose, glucose and fructose levels of the leaf blade had already increased over 5-fold, and the activities of SS and INV(A) had increased c. 1.5-2 times. From 9 DAW on, when stress intensity was more pronounced, these effects were reversed with fructose and glucose concentrations as well as INV(A) activity dropping in parallel. The stem (specifically the stele) responded to the stress intensification with striking increases in the concentration of sugars, N and S, and in the induction of thaumatin-like-protein and an increase in chitinase and peroxidase. At 13 DAW, the plants lost most of the leaves but on rewatering they fully recovered. Thus, the observed changes appear to contribute to a general mechanism of survival under drought, the stem playing a key role in that process.

  11. Establishing research strategies, methodologies and technologies to link genomics and proteomics to seagrass productivity, community metabolism, and ecosystem carbon fluxes.

    Science.gov (United States)

    Mazzuca, Silvia; Björk, M; Beer, S; Felisberto, P; Gobert, S; Procaccini, G; Runcie, J; Silva, J; Borges, A V; Brunet, C; Buapet, P; Champenois, W; Costa, M M; D'Esposito, D; Gullström, M; Lejeune, P; Lepoint, G; Olivé, I; Rasmusson, L M; Richir, J; Ruocco, M; Serra, I A; Spadafora, A; Santos, Rui

    2013-01-01

    A complete understanding of the mechanistic basis of marine ecosystem functioning is only possible through integrative and interdisciplinary research. This enables the prediction of change and possibly the mitigation of the consequences of anthropogenic impacts. One major aim of the European Cooperation in Science and Technology (COST) Action ES0609 "Seagrasses productivity. From genes to ecosystem management," is the calibration and synthesis of various methods and the development of innovative techniques and protocols for studying seagrass ecosystems. During 10 days, 20 researchers representing a range of disciplines (molecular biology, physiology, botany, ecology, oceanography, and underwater acoustics) gathered at The Station de Recherches Sous-marines et Océanographiques (STARESO, Corsica) to study together the nearby Posidonia oceanica meadow. STARESO is located in an oligotrophic area classified as "pristine site" where environmental disturbances caused by anthropogenic pressure are exceptionally low. The healthy P. oceanica meadow, which grows in front of the research station, colonizes the sea bottom from the surface to 37 m depth. During the study, genomic and proteomic approaches were integrated with ecophysiological and physical approaches with the aim of understanding changes in seagrass productivity and metabolism at different depths and along daily cycles. In this paper we report details on the approaches utilized and we forecast the potential of the data that will come from this synergistic approach not only for P. oceanica but for seagrasses in general.

  12. Establishing research strategies, methodologies and technologies to link genomics and proteomics to seagrass productivity, community metabolism and ecosystem carbon fluxes

    Directory of Open Access Journals (Sweden)

    Silvia eMazzuca

    2013-03-01

    Full Text Available A complete understanding of the mechanistic basis of marine ecosystem functioning is only possible through integrative and interdisciplinary research. This enables the prediction of change and possibly the mitigation of the consequences of anthropogenic impacts. One major aim of the COST Action ES0609 Seagrasses productivity. From genes to ecosystem management, is the calibration and synthesis of various methods and the development of innovative techniques and protocols for studying seagrass ecosystems.During ten days, twenty researchers representing a range of disciplines (molecular biology, physiology, botany, ecology, oceanography, underwater acoustics gathered at the marine station of STARESO (Corsica to study together the nearby Posidonia oceanica meadow. The Station de Recherches Sous-marine et Océanographiques (STARESO is located in an oligotrophic area classified as "pristine site" where environmental disturbances caused by anthropogenic pressure are exceptionally low. The healthy P. oceanica meadow, that grows in front of the lab, colonizes the sea bottom from the surface to 37 m depth. During the study, genomic and proteomic approaches were integrated with ecophysiological and physical approaches with the aim of understanding changes in seagrass productivity and metabolism at different depths and along daily cycles. In this paper we report details on the approaches utilized and we forecast the potential of the data that will come from this synergistic approach not only for P. oceanica but for seagrasses in general.

  13. Quantitative proteomics of heavy metal exposure in Arabidopsis thaliana reveals alterations in one-carbon metabolism enzymes upon exposure to zinc.

    Science.gov (United States)

    Barkla, Bronwyn J; Vera-Estrella, Rosario; Miranda-Vergara, María Cristina; Pantoja, Omar

    2014-12-05

    Plant zinc (Zn) homeostasis must be tightly regulated as the requirement for this micronutrient necessitates its uptake. However, excessive Zn can lead to toxicity and the plant must respond rapidly and effectively within its capacity to minimize damage. To detect mechanisms that may be important for coping with excess Zn we carried out a quantitative proteomics approach using 2D-DIGE to identify Zn-responsive proteins in microsomal fractions from leaves of 4day, 200μM Zn-treated, Arabidopsis thaliana plants. Of the eight proteins which showed significant changes in abundance in the Zn-treated samples and which met all of the selection criteria following statistical analysis, six were successfully identified by LC-MS/MS with 2 or more unique peptides. Three of the proteins were found to be involved in the one-carbon metabolism pathway; including glycine decarboxylase P protein, serine hydroxymethyltransferase (SHMT) and methionine synthase, all of which showed reduced abundance in the Zn-treated samples. Western blot analysis confirmed the decrease in SHMT, while changes in metal tolerance protein indicated plants were most likely actively sequestering Zn. Interestingly, excess Zn led to increased petiole length, a phenotype which may reflect the reduced levels of methionine, a key product of the one-carbon metabolism pathway. Metal contamination is becoming an increasingly common environmental problem. High levels of zinc can be found in certain soils naturally or as a result of long-term anthropogenic activity which leads to its accumulation; i.e. use of fertilizers or industrial waste. The study of metal tolerant plants, particularly those classified as hyperaccumulators has been driven by the potential use of these plants for bioremediation purposes. However, the effects of heavy metal exposure on sensitive plants and the different cellular processes that are affected have received significantly less attention. We are interested in identifying proteins in A

  14. Long-Term, Supplemental, One-Carbon Metabolism-Related Vitamin B Use in Relation to Lung Cancer Risk in the Vitamins and Lifestyle (VITAL) Cohort.

    Science.gov (United States)

    Brasky, Theodore M; White, Emily; Chen, Chi-Ling

    2017-10-20

    Purpose Inconsistent findings have been reported of a link between the use of one-carbon metabolism-related B vitamins and lung cancer risk. Because of the high prevalence of supplemental vitamin B use, any possible increased association warrants further investigation. We examined the association between long-term use of supplemental B vitamins on the one-carbon metabolism pathway and lung cancer risk in the Vitamins and Lifestyle (VITAL) cohort, which was designed specifically to look at supplement use relative to cancer risk. Methods A total of 77,118 participants of the VITAL cohort, 50 to 76 years of age, were recruited between October 2000 and December 2002 and included in this analysis. Incident, primary, invasive lung cancers (n = 808) were ascertained by prospectively linking the participants to a population-based cancer registry. The 10-year average daily dose from individual and multivitamin supplements were the exposures of primary interest. Results Use of supplemental vitamins B 6 , folate, and B 12 was not associated with lung cancer risk among women. In contrast, use of vitamin B 6 and B 12 from individual supplement sources, but not from multivitamins, was associated with a 30% to 40% increase in lung cancer risk among men. When the 10-year average supplement dose was evaluated, there was an almost two-fold increase in lung cancer risk among men in the highest categories of vitamin B 6 (> 20 mg/d; hazard ratio, 1.82; 95% CI, 1.25 to 2.65) and B 12 (> 55µg/d; hazard ratio, 1.98; 95% CI, 1.32 to 2.97) compared with nonusers. For vitamin B 6 and B 12 , the risk was even higher among men who were smoking at baseline. In addition, the B 6 and B 12 associations were apparent in all histologic types except adenocarcinoma, which is the type less related to smoking. Conclusion This sex- and source-specific association provides further evidence that vitamin B supplements are not chemopreventive for lung cancer and may be harmful.

  15. Foliar photochemical processes and carbon metabolism under favourable and adverse winter conditions in a Mediterranean mixed forest, Catalonia (Spain)

    Science.gov (United States)

    Sperlich, D.; Chang, C. T.; Peñuelas, J.; Gracia, C.; Sabaté, S.

    2014-10-01

    Evergreen trees in the Mediterranean region must cope with a wide range of environmental stresses from summer drought to winter cold. The mildness of Mediterranean winters can periodically lead to favourable environmental conditions above the threshold for a positive carbon balance, benefitting evergreen woody species more than deciduous ones. The comparatively lower solar energy input in winter decreases the foliar light saturation point. This leads to a higher susceptibility to photoinhibitory stress especially when chilly (Arbutus unedo L.). Therefore, we collected twigs from the field during a period of mild winter conditions and after a sudden cold period. After both periods, the state of the photosynthetic machinery was tested in the laboratory by estimating the foliar photosynthetic potential with CO2 response curves in parallel with chlorophyll fluorescence measurements. The studied evergreen tree species benefited strongly from mild winter conditions by exhibiting extraordinarily high photosynthetic potentials. A sudden period of frost, however, negatively affected the photosynthetic apparatus, leading to significant decreases in key physiological parameters such as the maximum carboxylation velocity (Vc, max), the maximum photosynthetic electron transport rate (Jmax), and the optimal fluorometric quantum yield of photosystem II (Fv/Fm). The responses of Vc, max and Jmax were highly species specific, with Q. ilex exhibiting the highest and P. halepensis the lowest reductions. In contrast, the optimal fluorometric quantum yield of photosystem II (Fv/Fm) was significantly lower in A. unedo after the cold period. The leaf position played an important role in Q. ilex showing a stronger winter effect on sunlit leaves in comparison to shaded leaves. Our results generally agreed with the previous classifications of photoinhibition-tolerant (P. halepensis) and photoinhibition-avoiding (Q. ilex) species on the basis of their susceptibility to dynamic

  16. Old Wine in New Wine Skins: Tombstone Unveiling as a Case of ...

    African Journals Online (AJOL)

    This article reflects on the practice of Tombstone Unveiling, a recent phenomenon among Shona Christians in Zimbabwe, as a case of religious change. Historically, many church doctrines and practices have been negative towards African Traditional Religions (ATRs). Shona Christians have reacted by trying to ...

  17. Atomic Force Microscopy - A Tool to Unveil the Mystery of Biological ...

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 15; Issue 7. Atomic Force Microscopy - A Tool to Unveil the Mystery of Biological Systems ... Transcription and Disease Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560 ...

  18. Carbon Dioxide Impacts in the Deep-Sea: Is Maintaining a Metabolically Required CO2 Efflux Rate Challenging?

    Science.gov (United States)

    Peltzer, E. T.; Hofmann, A. F.; Brewer, P. G.

    2011-12-01

    Increasing ocean acidification from fossil fuel CO2 invasion, from temperature driven changes in respiration, and from possible leakage from sub-seabed geologic CO2 disposal has aroused concern over the impacts of elevated CO2 concentrations on marine life. Here we describe the rate problem for animals who must export CO2 at about the same rate at which O2 is consumed. We analyze the basic properties controlling CO2 export within the diffusive boundary of marine animals in a changing ocean in order to compare the challenges posed by O2 uptake under stress with the equivalent problem of CO2 expulsion. The problem is more complex than that for a non-reactive gas since, as with gas exchange of CO2 at the air-sea interface, the influence of the ensemble of reactions within the CO2 - HCO3- - CO3= acid-base system needs to be considered. These reactions appear as an enhancement factor which significantly facilitates CO2 efflux compared to O2 intake at equal temperature, pressure and flow rate under typical oceanic concentrations. Possibly as an adaptation to this chemical advantage marine animals typically can respond to external CO2 stress simply by metabolic adjustment. This is energetically more favorable than having to resort to mechanically increasing flow over their surface to thin the boundary layer as is required to alleviate O2 stress. Regionally as with O2 the combination of T, P, and pH/pCO2 creates a zone of maximum CO2 stress at around 1000 m depth. But the net result is that the combination of an increase in T combined with declining O2 poses a greater respiratory challenge to marine life than does increasing CO2. The relationships developed here allow a more accurate prediction of the impacts on marine life from the combined effects of changing T, O2, and CO2 than can be estimated from single variable studies.

  19. Structural evolution of calcite at high temperatures: Phase V unveiled

    Science.gov (United States)

    Ishizawa, Nobuo; Setoguchi, Hayato; Yanagisawa, Kazumichi

    2013-01-01

    The calcite form of calcium carbonate CaCO3 undergoes a reversible phase transition between Rc and Rm at ~1240 K under a CO2 atmosphere of ~0.4 MPa. The joint probability density function obtained from the single-crystal X-ray diffraction data revealed that the oxygen triangles of the CO3 group in the high temperature form (Phase V) do not sit still at specified positions in the space group Rm, but migrate along the undulated circular orbital about carbon. The present study also shows how the room temperature form (Phase I) develops into Phase V through an intermediate form (Phase IV) in the temperature range between ~985 K and ~1240 K. PMID:24084871

  20. 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

    Science.gov (United States)

    Liu, Tian-Qi; Cao, Cou-Gui; Li, Cheng-Fang

    2016-01-01

    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 tillage (NT and S) increased microbial metabolic activities and Shannon index in >0.25 and directly improved SOC by promoting DOC in >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 tillage increased SOC in aggregates in the topsoil by improving microbial metabolic activities. PMID:26731654

  1. Ancillary contributions of heterologous biotin protein ligase and carbonic anhydrase for CO2 incorporation into 3-hydroxypropionate by metabolically engineered Pyrococcus furiosus.

    Science.gov (United States)

    Lian, Hong; Zeldes, Benjamin M; Lipscomb, Gina L; Hawkins, Aaron B; Han, Yejun; Loder, Andrew J; Nishiyama, Declan; Adams, Michael W W; Kelly, Robert M

    2016-12-01

    Acetyl-Coenzyme A carboxylase (ACC), malonyl-CoA reductase (MCR), and malonic semialdehyde reductase (MRS) convert HCO 3 - and acetyl-CoA into 3-hydroxypropionate (3HP) in the 3-hydroxypropionate/4-hydroxybutyrate carbon fixation cycle resident in the extremely thermoacidophilic archaeon Metallosphaera sedula. These three enzymes, when introduced into the hyperthermophilic archaeon Pyrococcus furiosus, enable production of 3HP from maltose and CO 2 . Sub-optimal function of ACC was hypothesized to be limiting for production of 3HP, so accessory enzymes carbonic anhydrase (CA) and biotin protein ligase (BPL) from M. sedula were produced recombinantly in Escherichia coli to assess their function. P. furiosus lacks a native, functional CA, while the M. sedula CA (Msed_0390) has a specific activity comparable to other microbial versions of this enzyme. M. sedula BPL (Msed_2010) was shown to biotinylate the β-subunit (biotin carboxyl carrier protein) of the ACC in vitro. Since the native BPLs in E. coli and P. furiosus may not adequately biotinylate the M. sedula ACC, the carboxylase was produced in P. furiosus by co-expression with the M. sedula BPL. The baseline production strain, containing only the ACC, MCR, and MSR, grown in a CO 2 -sparged bioreactor reached titers of approximately 40 mg/L 3HP. Strains in which either the CA or BPL accessory enzyme from M. sedula was added to the pathway resulted in improved titers, 120 or 370 mg/L, respectively. The addition of both M. sedula CA and BPL, however, yielded intermediate titers of 3HP (240 mg/L), indicating that the effects of CA and BPL on the engineered 3HP pathway were not additive, possible reasons for which are discussed. While further efforts to improve 3HP production by regulating gene dosage, improving carbon flux and optimizing bioreactor operation are needed, these results illustrate the ancillary benefits of accessory enzymes for incorporating CO 2 into 3HP production in metabolically engineered P

  2. Novel mode of microbial energy metabolism: organic carbon oxidation coupled to dissimilatory reduction of iron or manganese.

    Science.gov (United States)

    Lovley, D R; Phillips, E J

    1988-06-01

    A dissimilatory Fe(III)- and Mn(IV)-reducing microorganism was isolated from freshwater sediments of the Potomac River, Maryland. The isolate, designated GS-15, grew in defined anaerobic medium with acetate as the sole electron donor and Fe(III), Mn(IV), or nitrate as the sole electron acceptor. GS-15 oxidized acetate to carbon dioxide with the concomitant reduction of amorphic Fe(III) oxide to magnetite (Fe(3)O(4)). When Fe(III) citrate replaced amorphic Fe(III) oxide as the electron acceptor, GS-15 grew faster and reduced all of the added Fe(III) to Fe(II). GS-15 reduced a natural amorphic Fe(III) oxide but did not significantly reduce highly crystalline Fe(III) forms. Fe(III) was reduced optimally at pH 6.7 to 7 and at 30 to 35 degrees C. Ethanol, butyrate, and propionate could also serve as electron donors for Fe(III) reduction. A variety of other organic compounds and hydrogen could not. MnO(2) was completely reduced to Mn(II), which precipitated as rhodochrosite (MnCO(3)). Nitrate was reduced to ammonia. Oxygen could not serve as an electron acceptor, and it inhibited growth with the other electron acceptors. This is the first demonstration that microorganisms can completely oxidize organic compounds with Fe(III) or Mn(IV) as the sole electron acceptor and that oxidation of organic matter coupled to dissimilatory Fe(III) or Mn(IV) reduction can yield energy for microbial growth. GS-15 provides a model for how enzymatically catalyzed reactions can be quantitatively significant mechanisms for the reduction of iron and manganese in anaerobic environments.

  3. Rain-Shelter Cultivation Modifies Carbon Allocation in the Polyphenolic and Volatile Metabolism of Vitis vinifera L. Chardonnay Grapes

    Science.gov (United States)

    Han, Mei-Mei; Yang, Xiao-Fan; Li, Zheng; Wang, Jun; Pan, Qiu-Hong

    2016-01-01

    This study investigated the effect of rain-shelter cultivation on the biosynthesis of flavonoids and volatiles in grapes, with an aim of determining whether rain-shelter application could help to improve the sensory attributes and quality of grapes. Vitis vinifera L. Chardonnay grapes, grown in the Huaizhuo basin region of northern China, were selected within two consecutive years. A rain-shelter roof was constructed using a colorless polyethylene (PE) film with a light transmittance of 80%. Results showed that rain-shelter treatment did not affect the accumulation of soluble solids during grape maturation. However, the allocation of assimilated carbon in phenolic and volatile biosynthetic pathways varied significantly, leading to alterations in polyphenolic and volatile profiles. The rain-shelter cultivation enhanced the concentration of flavan-3-ols via the flavonoid-3’5’-hydroxylase (F3’5’H) pathway, but reduced the level of flavonols and flavan-3-ols via the flavonoid-3’-hydroxylase (F3’H) pathway. In addition, the rain-shelter cultivation significantly enhanced the synthesis of fatty acid-derived volatiles, isoprene-derived terpenoids and amino acid-derived branched-chain aliphatics, but led to a decrease in the accumulation of isoprene-derived norisoprenoids and amino acid-derived benzenoids. Principal component analysis revealed some key compounds that differentiated the grapes cultivated under open-field and rain-shelter conditions. Moreover, the effect of the rain-shelter application on the accumulation of these compounds appeared to be vintage dependent. The alteration of their profiles caused by the rain-shelter treatment was significant in the vintage that received higher rainfall, which usually took place in the first rapid growth and veraison phases. PMID:27218245

  4. First Comparative Analysis of the Community Structures and Carbon Metabolic Pathways of the Bacteria Associated with Alvinocaris longirostris in a Hydrothermal Vent of Okinawa Trough.

    Science.gov (United States)

    Sun, Qing-Lei; Zeng, Zhi-Gang; Chen, Shuai; Sun, Li

    2016-01-01

    Alvinocaris longirostris is a species of shrimp existing in the hydrothermal fields of Okinawa Trough. To date the structure and function of the microbial community associated with A. longirostris are essentially unknown. In this study, by employment of the techniques of high through-put sequencing and clone library construction and analysis, we compared for the first time the community structures and metabolic profiles of microbes associated with the gill and gut of A. longirostris in a hydrothermal field of Okinawa Trough. Fourteen phyla were detected in the gill and gut communities, of which 11 phyla were shared by both tissues. Proteobacteria made up a substantial proportion in both tissues, while Firmicutes was abundant only in gut. Although gill and gut communities were similar in bacterial diversities, the bacterial community structures in these two tissues were significantly different. Further, we discovered for the first time the existence in the gill and gut communities of A. longirostris the genes (cbbM and aclB) encoding the key enzymes of Calvin-Benson-Bassham (CBB) cycle and the reductive tricarboxylic acid (rTCA) cycle, and that both cbbM and aclB were significantly more abundant in gill than in gut. Taken together, these results provide the first evidence that at least two carbon fixation pathways are present in both the gill and the gut communities of A. longirostris, and that the communities in different tissues likely differ in autotrophic productivity.

  5. First Comparative Analysis of the Community Structures and Carbon Metabolic Pathways of the Bacteria Associated with Alvinocaris longirostris in a Hydrothermal Vent of Okinawa Trough.

    Directory of Open Access Journals (Sweden)

    Qing-Lei Sun

    Full Text Available Alvinocaris longirostris is a species of shrimp existing in the hydrothermal fields of Okinawa Trough. To date the structure and function of the microbial community associated with A. longirostris are essentially unknown. In this study, by employment of the techniques of high through-put sequencing and clone library construction and analysis, we compared for the first time the community structures and metabolic profiles of microbes associated with the gill and gut of A. longirostris in a hydrothermal field of Okinawa Trough. Fourteen phyla were detected in the gill and gut communities, of which 11 phyla were shared by both tissues. Proteobacteria made up a substantial proportion in both tissues, while Firmicutes was abundant only in gut. Although gill and gut communities were similar in bacterial diversities, the bacterial community structures in these two tissues were significantly different. Further, we discovered for the first time the existence in the gill and gut communities of A. longirostris the genes (cbbM and aclB encoding the key enzymes of Calvin-Benson-Bassham (CBB cycle and the reductive tricarboxylic acid (rTCA cycle, and that both cbbM and aclB were significantly more abundant in gill than in gut. Taken together, these results provide the first evidence that at least two carbon fixation pathways are present in both the gill and the gut communities of A. longirostris, and that the communities in different tissues likely differ in autotrophic productivity.

  6. Improving Predictions of Tree Drought Mortality in the Community Land Model Using Hydraulic Physiology Theory and its Effects on Carbon Metabolism

    Science.gov (United States)

    McNellis, B.; Hudiburg, T. W.

    2017-12-01

    Tree mortality due to drought is predicted to have increasing impacts on ecosystem structure and function during the 21st century. Models can attempt to predict which forests are most at risk from drought, but novel environments may preclude analysis that relies on past observations. The inclusion of more mechanistic detail may reduce uncertainty in predictions, but can also compound model complexity, especially in global models. The Community Land Model version 5 (CLM5), itself a component of the Community Earth System Model (CESM), has recently integrated cohort-based demography into its dynamic vegetation component and is in the process of coupling this demography to a model of plant hydraulic physiology (FATES-Hydro). Previous treatment of drought stress and plant mortality within CLM has been relatively broad, but a detailed hydraulics module represents a key step towards accurate mortality prognosis. Here, we examine the structure of FATES-Hydro with respect to two key physiological attributes: tissue osmotic potentials and embolism refilling. Specifically, we ask how FATES-Hydro captures mechanistic realism within each attribute and how much support there is within the physiological literature for its further elaboration within the model structure. Additionally, connections to broader aspects of carbon metabolism within FATES are explored to better resolve emergent consequences of drought stress on ecosystem function and tree demographics. An on-going field experiment in managed stands of Pinus ponderosa and mixed conifers is assessed for model parameterization and performance across PNW forests, with important implications for future forest management strategy.

  7. Double silencing of relevant genes suggests the existence of the direct link between DNA replication/repair and central carbon metabolism in human fibroblasts.

    Science.gov (United States)

    Wieczorek, Aneta; Fornalewicz, Karolina; Mocarski, Łukasz; Łyżeń, Robert; Węgrzyn, Grzegorz

    2018-04-15

    Genetic evidence for a link between DNA replication and glycolysis has been demonstrated a decade ago in Bacillus subtilis, where temperature-sensitive mutations in genes coding for replication proteins could be suppressed by mutations in genes of glycolytic enzymes. Then, a strong influence of dysfunctions of particular enzymes from the central carbon metabolism (CCM) on DNA replication and repair in Escherichia coli was reported. Therefore, we asked if such a link occurs only in bacteria or it is a more general phenomenon. Here, we demonstrate that effects of silencing (provoked by siRNA) of expression of genes coding for proteins involved in DNA replication and repair (primase, DNA polymerase ι, ligase IV, and topoisomerase IIIβ) on these processes (less efficient entry into the S phase of the cell cycle and decreased level of DNA synthesis) could be suppressed by silencing of specific genes of enzymes from CMM. Silencing of other pairs of replication/repair and CMM genes resulted in enhancement of the negative effects of lower expression levels of replication/repair genes. We suggest that these results may be proposed as a genetic evidence for the link between DNA replication/repair and CMM in human cells, indicating that it is a common biological phenomenon, occurring from bacteria to humans. Copyright © 2018 Elsevier B.V. All rights reserved.

  8. Metabolic and transcriptomic response of the wine yeast Saccharomyces cerevisiae strain EC1118 after an oxygen impulse under carbon-sufficient, nitrogen-limited fermentative conditions.

    Science.gov (United States)

    Orellana, Marcelo; Aceituno, Felipe F; Slater, Alex W; Almonacid, Leonardo I; Melo, Francisco; Agosin, Eduardo

    2014-05-01

    During alcoholic fermentation, Saccharomyces cerevisiae is exposed to continuously changing environmental conditions, such as decreasing sugar and increasing ethanol concentrations. Oxygen, a critical nutrient to avoid stuck and sluggish fermentations, is only discretely available throughout the process after pump-over operation. In this work, we studied the physiological response of the wine yeast S. cerevisiae strain EC1118 to a sudden increase in dissolved oxygen, simulating pump-over operation. With this aim, an impulse of dissolved oxygen was added to carbon-sufficient, nitrogen-limited anaerobic continuous cultures. Results showed that genes related to mitochondrial respiration, ergosterol biosynthesis, and oxidative stress, among other metabolic pathways, were induced after the oxygen impulse. On the other hand, mannoprotein coding genes were repressed. The changes in the expression of these genes are coordinated responses that share common elements at the level of transcriptional regulation. Beneficial and detrimental effects of these physiological processes on wine quality highlight the dual role of oxygen in 'making or breaking wines'. These findings will facilitate the development of oxygen addition strategies to optimize yeast performance in industrial fermentations. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  9. Metabolic engineering of cyanobacteria for the synthesis of commodity products

    NARCIS (Netherlands)

    Angermayr, S.A.; Gorchs Rovira, A.; Hellingwerf, K.J.

    2015-01-01

    Through metabolic engineering cyanobacteria can be employed in biotechnology. Combining the capacity for oxygenic photosynthesis and carbon fixation with an engineered metabolic pathway allows carbon-based product formation from CO2, light, and water directly. Such cyanobacterial 'cell factories'

  10. Unveiling the transcriptional features associated with coccolithovirus infection of natural Emiliania huxleyi blooms.

    Science.gov (United States)

    Pagarete, António; Le Corguillé, Gildas; Tiwari, Bela; Ogata, Hiroyuki; de Vargas, Colomban; Wilson, William H; Allen, Michael J

    2011-12-01

    Lytic viruses have been implicated in the massive cellular lysis observed during algal blooms, through which they assume a prominent role in oceanic carbon and nutrient flows. Despite their impact on biogeochemical cycling, the transcriptional dynamics of these important oceanic events is still poorly understood. Here, we employ an oligonucleotide microarray to monitor host (Emiliania huxleyi) and virus (coccolithovirus) transcriptomic features during the course of E. huxleyi blooms induced in seawater-based mesocosm enclosures. Host bloom development and subsequent coccolithovirus infection was associated with a major shift in transcriptional profile. In addition to the expected metabolic requirements typically associated with viral infection (amino acid and nucleotide metabolism, as well as transcription- and replication-associated functions), the results strongly suggest that the manipulation of lipid metabolism plays a fundamental role during host-virus interaction. The results herein reveal the scale, so far massively underestimated, of the transcriptional domination that occurs during coccolithovirus infection in the natural environment. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  11. Using logic programming for modeling the one-carbon metabolism network to study the impact of folate deficiency on methylation processes.

    Science.gov (United States)

    Gnimpieba, Etienne Z; Eveillard, Damien; Guéant, Jean-Louis; Chango, Abalo

    2011-08-01

    Dynamical modeling is an accurate tool for describing the dynamic regulation of one-carbon metabolism (1CM) with emphasis on the alteration of DNA methylation and/or dUMP methylation into dTMP. Using logic programming we present a comprehensive and adaptative mathematical model to study the impact of folate deficiency, including folate transport and enzymes activities. 5-Methyltetrahydrofolate (5mTHF) uptake and DNA and dUMP methylation were studied by simulating nutritional 5mTHF deficiency and methylenetetrahydrofolate reductase (MTHFR) gene defects. Both conditions had distinct effects on 1CM metabolite synthesis. Simulating severe 5mTHF deficiency (25% of normal levels) modulated 11 metabolites. However, simulating a severe decrease in MTHFR activity (25% of normal activity) modulated another set of metabolites. Two oscillations of varying amplitude were observed at the steady state for DNA methylation with severe 5mTHF deficiency, and the dUMP/dTMP ratio reached a steady state after 2 h, compared to 2.5 h for 100% 5mTHF. MTHFR activity with 25% of V(max) resulted in an increased methylated DNA pool after half an hour. We observed a deviation earlier in the profile compared to 50% and 100% V(max). For dUMP methylation, the highest level was observed with 25%, suggesting a low rate of dUMP methylation into dTMP with 25% of MTHFR activity. In conclusion, using logic programming we were able to construct the 1CM for analyzing the dynamic system behavior. This model may be used to refine biological interpretations of data or as a tool that can provide new hypotheses for pathogenesis.

  12. 2012 Molecular Basis of Microbial One-Carbon Metabolism Gordon Research Conferences and Gordon Research Seminar, August 4-10,2012

    Energy Technology Data Exchange (ETDEWEB)

    Hanson, Thomas

    2012-08-10

    The 2012 Gordon Conference will present and discuss cutting-edge research in the field of microbial metabolism of C1 compounds. The conference will feature the roles and application of C1 metabolism in natural and synthetic systems at scales from molecules to ecosystems. The conference will stress molecular aspects of the unique metabolism exhibited by autotrophic bacteria, methanogens, methylotrophs, aerobic and anaerobic methanotrophs, and acetogens.

  13. Genome-scale comparison and constraint-based metabolic reconstruction of the facultative anaerobic Fe(III-reducer Rhodoferax ferrireducens

    Directory of Open Access Journals (Sweden)

    Daugherty Sean

    2009-09-01

    Full Text Available Abstract Background Rhodoferax ferrireducens is a metabolically versatile, Fe(III-reducing, subsurface microorganism that is likely to play an important role in the carbon and metal cycles in the subsurface. It also has the unique ability to convert sugars to electricity, oxidizing the sugars to carbon dioxide with quantitative electron transfer to graphite electrodes in microbial fuel cells. In order to expand our limited knowledge about R. ferrireducens, the complete genome sequence of this organism was further annotated and then the physiology of R. ferrireducens was investigated with a constraint-based, genome-scale in silico metabolic model and laboratory studies. Results The iterative modeling and experimental approach unveiled exciting, previously unknown physiological features, including an expanded range of substrates that support growth, such as cellobiose and citrate, and provided additional insights into important features such as the stoichiometry of the electron transport chain and the ability to grow via fumarate dismutation. Further analysis explained why R. ferrireducens is unable to grow via photosynthesis or fermentation of sugars like other members of this genus and uncovered novel genes for benzoate metabolism. The genome also revealed that R. ferrireducens is well-adapted for growth in the subsurface because it appears to be capable of dealing with a number of environmental insults, including heavy metals, aromatic compounds, nutrient limitation and oxidative stress. Conclusion This study demonstrates that combining genome-scale modeling with the annotation of a new genome sequence can guide experimental studies and accelerate the understanding of the physiology of under-studied yet environmentally relevant microorganisms.

  14. The crystal structures of the tryparedoxin-tryparedoxin peroxidase couple unveil the structural determinants of Leishmania detoxification pathway.

    Directory of Open Access Journals (Sweden)

    Annarita Fiorillo

    Full Text Available Leishmaniasis is a neglected disease caused by Leishmania, an intracellular protozoan parasite which possesses a unique thiol metabolism based on trypanothione. Trypanothione is used as a source of electrons by the tryparedoxin/tryparedoxin peroxidase system (TXN/TXNPx to reduce the hydroperoxides produced by macrophages during infection. This detoxification pathway is not only unique to the parasite but is also essential for its survival; therefore, it constitutes a most attractive drug target. Several forms of TXNPx, with very high sequence identity to one another, have been found in Leishmania strains, one of which has been used as a component of a potential anti-leishmanial polyprotein vaccine. The structures of cytosolic TXN and TXNPx from L. major (LmTXN and LmTXNPx offer a unique opportunity to study peroxide reduction in Leishmania parasites at a molecular level, and may provide new tools for multienzyme inhibition-based drug discovery. Structural analyses bring out key structural features to elucidate LmTXN and LmTXNPx function. LmTXN displays an unusual N-terminal α-helix which allows the formation of a stable domain-swapped dimer. In LmTXNPx, crystallized in reducing condition, both the locally unfolded (LU and fully folded (FF conformations, typical of the oxidized and reduced protein respectively, are populated. The structural analysis presented here points to a high flexibility of the loop that includes the peroxidatic cysteine which facilitates Cys52 to form an inter-chain disulfide bond with the resolving cysteine (Cys173, thereby preventing over-oxidation which would inactivate the enzyme. Analysis of the electrostatic surface potentials of both LmTXN and LmTXNPx unveils the structural elements at the basis of functionally relevant interaction between the two proteins. Finally, the structural analysis of TXNPx allows us to identify the position of the epitopes that make the protein antigenic and therefore potentially suitable

  15. Differential metabolic responses of Beauveria bassiana cultured in pupae extracts, root exudates and its interactions with insect and plant.

    Science.gov (United States)

    Luo, Feifei; Wang, Qian; Yin, Chunlin; Ge, Yinglu; Hu, Fenglin; Huang, Bo; Zhou, Hong; Bao, Guanhu; Wang, Bin; Lu, Ruili; Li, Zengzhi

    2015-09-01

    and distilled water. This indicates that fungal fatty acid metabolism is enhanced when contacting insect, but when in the absence of insect hosts NRP synthesis is increased. Ornithine, arginine and GABA are decreased in mycelia cultured in pupae extracts and root exudates but remain unchanged in distilled water, which suggests that they may be associated with fungal cross-talk with insects and plants. Trehalose and mannitol are decreased while adenine is increased in three conditions, signifying carbon shortage in cells. Together, these results unveil that B. bassiana has differential metabolic responses in pupae extracts and root exudates, and metabolic similarity in root exudates and distilled water is possibly due to the lack of insect components. Copyright © 2015. Published by Elsevier Inc.

  16. Suppression of the Escherichia coli dnaA46 mutation by changes in the activities of the pyruvate-acetate node links DNA replication regulation to central carbon metabolism.

    Science.gov (United States)

    Tymecka-Mulik, Joanna; Boss, Lidia; Maciąg-Dorszyńska, Monika; Matias Rodrigues, João F; Gaffke, Lidia; Wosinski, Anna; Cech, Grzegorz M; Szalewska-Pałasz, Agnieszka; Węgrzyn, Grzegorz; Glinkowska, Monika

    2017-01-01

    To ensure faithful transmission of genetic material to progeny cells, DNA replication is tightly regulated, mainly at the initiation step. Escherichia coli cells regulate the frequency of initiation according to growth conditions. Results of the classical, as well as the latest studies, suggest that the DNA replication in E. coli starts at a predefined, constant cell volume per chromosome but the mechanisms coordinating DNA replication with cell growth are still not fully understood. Results of recent investigations have revealed a role of metabolic pathway proteins in the control of cell division and a direct link between metabolism and DNA replication has also been suggested both in Bacillus subtilis and E. coli cells. In this work we show that defects in the acetate overflow pathway suppress the temperature-sensitivity of a defective replication initiator-DnaA under acetogenic growth conditions. Transcriptomic and metabolic analyses imply that this suppression is correlated with pyruvate accumulation, resulting from alterations in the pyruvate dehydrogenase (PDH) activity. Consequently, deletion of genes encoding the pyruvate dehydrogenase subunits likewise resulted in suppression of the thermal-sensitive growth of the dnaA46 strain. We propose that the suppressor effect may be directly related to the PDH complex activity, providing a link between an enzyme of the central carbon metabolism and DNA replication.

  17. Unveiling EFL and Self-Contained Teachers’ Discourses on Bilingualism Within the Context of Professional Development

    Directory of Open Access Journals (Sweden)

    Jennyfer Paola Camargo Cely

    2018-01-01

    Full Text Available Throughout time, the predominant use of certain languages has allowed some nations to take control over others and assure for them a privileged position. This study unveiled how certain practices and ideologies in regard to bilingualism have influenced teachers’ professional development. Data were collected through discussion group sessions, reflective journals, and protocols from five teachers from a private K-11 school in Bogota. Analysis indicated participants’ discourses drew on hegemonic, colonial, and manipulative ideas. Nevertheless, when dialoguing and peer coaching, a discourse of resistance was constituted. The study suggested further research into teachers’ professional growth, bilingualism, and bilingual education in monolingual contexts as the Colombian one.

  18. Effects of phosphorus application on photosynthetic carbon and nitrogen metabolism, water use efficiency and growth of dwarf bamboo (Fargesia rufa) subjected to water deficit.

    Science.gov (United States)

    Liu, Chenggang; Wang, Yanjie; Pan, Kaiwen; Jin, Yanqiang; Li, Wei; Zhang, Lin

    2015-11-01

    Dwarf bamboo (Fargesia rufa Yi), one of the staple foods for the endangered giant pandas, is highly susceptible to water deficit due to its shallow roots. In the face of climate change, maintenance and improvement in its productivity is very necessary for the management of the giant pandas' habitats. However, the regulatory mechanisms underlying plant responses to water deficit are poorly known. To investigate the effects of P application on photosynthetic C and N metabolism, water use efficiency (WUE) and growth of dwarf bamboo under water deficit, a completely randomized design with two factors of two watering (well-watered and water-stressed) and two P regimes (with and without P fertilization) was arranged. P application hardly changed growth, net CO2 assimilation rate (P(n)) and WUE in well-watered plants but significantly increased relative growth rate (RGR) and P(n) in water-stressed plants. The effect of P application on RGR under water stress was mostly associated with physiological adjustments rather than with differences in biomass allocation. P application maintained the balance of C metabolism in well-watered plants, but altered the proportion of nitrogenous compounds in N metabolism. By contrast, P application remarkably increased sucrose-metabolizing enzymes activities with an obvious decrease in sucrose content in water-stressed plants, suggesting an accelerated sucrose metabolism. Activation of nitrogen-metabolizing enzymes in water-stressed plants was attenuated after P application, thus slowing nitrate reduction and ammonium assimilation. P application hardly enlarged the phenotypic plasticity of dwarf bamboo in response to water in the short term. Generally, these examined traits of dwarf bamboo displayed weak or negligible responses to water-P interaction. In conclusion, P application could accelerate P(n) and sucrose metabolism and slow N metabolism in water-stressed dwarf bamboo, and as a result improved RGR and alleviated damage from soil

  19. Uzbekistan unveiled

    International Nuclear Information System (INIS)

    Mazurkevich, A.P.

    1993-01-01

    Through centuries of revolution, war and strife, the people of Uzbekistan have built a reputation as skilled and tenacious merchants. Since antiquity, when the Silk Road from China turned toward Europe at Smarakand, they have been master traders of such valuable commodities as cotton, fruits, vegetables, spices and gold. Now, they're about to introduce another of their specialties to the world: Uranium. Uranium mining in the country is controlled by a new, independent company, the Kizilkumredmetzoloto, parent of the Navoi Mining ampersand Metallurgy Combine [NMMC]. Established in 1958 at the height of the Cold War, when uranium mining for military stockpiles got started in earnest, Navoi was wholly owned by the USSR's Ministry of Medium Machine Building. Up until 1991, virtually all of Navoi's uranium production, strictly in the form of uranium concentrates, was used for either military purposes or for nuclear power plants within the former Soviet Union. The republic exerted no control over the final destination of its uranium. All production and operating decisions for Navoi's mines were dictated by the Soviet Union's Ministry of Atomic Power ampersand Industry [MAPI], which developed annual quotas for uranium production in each republic of the country. Uranium from the republics was sold to Techsnabexport [Tenex], the distribution and marketing arm of MAPI. Exports to other countries were handled strictly by Tenex

  20. From Multilatina to Global Latina: Unveiling the corporate-level international strategy choices of Grupo Nutresa

    Directory of Open Access Journals (Sweden)

    MARIA A DE VILLA

    Full Text Available Research on Multilatinas has underexplored multinationals from Colombia and their corporate-level international strategy choices to develop into Global Latinas. Building on interviews, documents, and archival data about Grupo Nutresa -Colombia's most international firm in manufactured goods-, this study unveils and discusses this firm's corporate-level international strategy choices between 1960 and 2014. A prevailing notion is that most multinationals from Latin America continue to target international operations to focus mainly on their home region through an export, multidomestic or transnational corporate-level international strategy. In contrast, data show that Grupo Nutresa chose to evolve through a sequential approach from an export to a transnational corporate-level international strategy while its international operations were able to transcend its home region to reach North America, Asia, Europe, Africa, and Oceania. These results add to international business research on emergent market multinational companies (EMNCs from Latin America by unveiling the corporate-level international strategy choices of a Colombian origin Multilatina that transformed into a Global Latina.

  1. Expectations and satisfaction of pregnant women: unveiling prenatal care in primary care.

    Science.gov (United States)

    Aparecida Maciel Cardelli, Alexandrina; Li Marrero, Tai; Aparecida Pimenta Ferrari, Rosângela; Trevisan Martins, Júlia; Serafim, Deise

    2016-06-01

    To analyze the perception of primiparous women about prenatal care in Basic Health Units in a municipality in southern Brazil. This is a qualitative research from the perspective of Social Representation Theory, from the following question: How has been the pre-natal care for you? Eighteen pregnant women were interviewed. The analysis resulted in three categories: Expectation representation about prenatal care; Rescuing the care offered in prenatal consultation; Unveiling the (dis) satisfaction with prenatal consultation. The prenatal care was apprehended as an essential moment for safe pregnancy, although centered on the doctor's figure and guarantee access to early laboratory and imaging tests. On the other hand, dissatisfaction was revealed from the reception at the entrance to the health unit to the consultations access, although some statements suggest timely satisfaction. Prenatal care did not meet the specific expectations of the study group and unveiled that the nurse did not supply it, as a member of the multidisciplinary team. The organization of the nursing work process in primary care, related to prenatal care, needs to be revisited to promote the effectiveness of its actions.

  2. Expectations and satisfaction of pregnant women: unveiling prenatal care in primary care

    Directory of Open Access Journals (Sweden)

    Alexandrina Aparecida Maciel Cardelli

    Full Text Available Objective.To analyze the perception of primiparous women about prenatal care in Basic Health Units in a municipality in southern Brazil. Methods. This is a qualitative research from the perspective of Social Representation Theory, from the following question: How has been the pre-natal care for you? Eighteen pregnant women were interviewed. Results. The analysis resulted in three categories: Expectation representation about prenatal care; Rescuing the care offered in prenatal consultation; Unveiling the (dis satisfaction with prenatal consultation. The prenatal care was apprehended as an essential moment for safe pregnancy, although centered on the doctor's figure and guarantee access to early laboratory and imaging tests. On the other hand, dissatisfaction was revealed from the reception at the entrance to the health unit to the consultations access, although some statements suggest timely satisfaction. Conclusion. Prenatal care did not meet the specific expectations of the study group and unveiled that the nurse did not supply it, as a member of the multidisciplinary team. The organization of the nursing work process in primary care, related to prenatal care, needs to be revisited to promote the effectiveness of its actions.

  3. Data analysis unveils a new stylized fact in foreign currency markets

    Science.gov (United States)

    Nacher, J. C.; Ochiai, T.

    2012-09-01

    The search for stylized facts (i.e., simplified empirical facts) is of capital importance in econophysics because the stylized facts constitute the experimental empirical body on which theories and models should be tested. At the moment they are too few and this is an important limitation to the progress in the field. In this work, we unveil a new stylized fact, which consists of resistance effect and breaking-acceleration effect that implicitly requires a long memory feature in price movement. By analyzing a vast amount of historical data, we demonstrate that the financial market tends to exceed a past (historical) extreme price less often than expected by a classic short-memory model (e.g., Black-Scholes model). We call it resistance effect. However, when the market does it, we predict that the average volatility at that time point will be much higher (accelerates more). It means, in average, volatility accelerates more when the price breaks the highest (lowest) value. We refer to this as breaking-acceleration effect. These observed empirical facts are actually an effect which may arise from technical trading and psychological effects. Taken together, these results indicate that, beyond the predictive capability of this unveiled stylized fact, traditional short-memory models do not faithfully capture the market dynamics.

  4. Noninvasive brain metabolism measurement using carbon-13 magnetic resonance spectroscopy ({sup 13}C-MRS); Tanso 13 jiki kyomei spectroscopy ({sup 13}C-MRS) ni yoru mushinshuteki notaisha keisoku

    Energy Technology Data Exchange (ETDEWEB)

    Okamoto, K.; Tsukada, Y. [Toshiba Corp., Tokyo (Japan)

    1998-10-10

    Carbon-13 magnetic resonance spectroscopy ({sup 13}C-MRS) and research and development efforts for brain metabolism measurement are described. Brain metabolism is a process characterized in that it not only extracts energy by disintegrating grape sugar that is the practically sole source of energy into H2O, CO2, etc., but also vigorously synthesizes amino acids that perform important functions in neural transmission, such as glutamic acid, glutamine, and {gamma}-amino acid. MRS is a technique that utilizes the magnetic resonance, which is generated when an atomic nucleus with a spin is placed in a magnetic field, for the isolation and identification of chemicals in a living body through examining the delicate difference in the magnetic resonance frequencies of the nuclei under observation. Since the signals from {sup 13}C are low in intensity as compared with those from other nuclides, a method was contrived around 1980, which observes {sup 1}H combined with {sup 13}C in grape sugar and amino acids, named the HSQC (heteronuclear single quantum coherence) method. The author et al., combining gradient magnetic pulses with HSQC, actually measure Homo sapiens brain metabolism using {sup 13}C-MRS, and now believe that the technology will be put to practical application. 7 refs., 10 figs., 1 tab.

  5. NASA's Great Observatories Celebrate the International Year of Astronomy With a National Unveiling of Spectacular Images

    Science.gov (United States)

    2009-02-01

    In 1609, Galileo first turned his telescope to the heavens and gave birth to modern astronomy. To commemorate four hundred years of exploring the universe, 2009 is designated the International Year of Astronomy. NASA's Great Observatories - the Hubble Space Telescope, Spitzer Space Telescope, and Chandra X-ray Observatory - are marking the occasion with the release of a suite of images at over 100 planetariums, museums, nature centers, and schools across the country in conjunction with Galileo's birthday on February 15. The selected sites will unveil a large 9-square-foot print of the spiral galaxy Messier 101 that combines the optical view of Hubble, the infrared view of Spitzer, and the X-ray view of Chandra into one multi-wavelength picture. "It's like using your eyes, night vision goggles, and X-ray vision all at the same time," says Dr. Hashima Hasan, lead scientist for the International Year of Astronomy at NASA Headquarters in Washington. Cas A animation Chandra X-ray Image of M101 Participating institutions also will display a matched trio of Hubble, Spitzer, and Chandra images of Messier 101. Each image shows a different wavelength view of the galaxy that illustrates not only the different science uncovered by each observatory, but also just how far astronomy has come since Galileo. Messier 101 is a face-on spiral galaxy about 22 million light-years away in the constellation Ursa Major. It is in many ways similar to, but larger than, our own Milky Way galaxy. Hubble's visible light view shows off the swirls of bright stars and glowing gas that give the galaxy its nickname the Pinwheel Galaxy. In contrast, Spitzer's infrared-light image sees into the spiral arms and reveals the glow of dust lanes where dense clouds can collapse to form new stars. Chandra's X-ray picture uncovers the high-energy features in the galaxy, such as remnants of exploded stars or matter zooming around black holes. The juxtaposition of observations from these three telescopes

  6. Molecular evidence for the coordination of nitrogen and carbon metabolisms, revealed by a study on the transcriptional regulation of the agl3EFG operon that encodes a putative carbohydrate transporter in Streptomyces coelicolor.

    Science.gov (United States)

    Cen, Xu-Feng; Wang, Jing-Zhi; Zhao, Guo-Ping; Wang, Ying; Wang, Jin

    2016-03-18

    In the agl3EFGXYZ operon (SCO7167-SCO7162, abbreviated as agl3 operon) of Streptomyces coelicolor M145, agl3EFG genes encode a putative ABC-type carbohydrate transporter. The transcription of this operon has been proved to be repressed by Agl3R (SCO7168), a neighboring GntR-family regulator, and this repression can be released by growth on poor carbon sources. Here in this study, we prove that the transcription of agl3 operon is also directly repressed by GlnR, a central regulator governing the nitrogen metabolism in S. coelicolor. The electrophoretic mobility shift assay (EMSA) employing the agl3 promoter and mixtures of purified recombinant GlnR and Agl3R indicates that GlnR and Agl3R bind to different DNA sequences within the promoter region of agl3 operon, which is further confirmed by the DNase I footprinting assay. As Agl3R and GlnR have been demonstrated to sense the extracellular carbon and nitrogen supplies, respectively, it is hypothesized that the transcription of agl3 operon is stringently governed by the availabilities of extracellular carbon and nitrogen sources. Consistent with the hypothesis, the agl3 operon is further found to be derepressed only under the condition of poor carbon and rich nitrogen supplies, when both regulators are inactivated. It is believed that activation of the expression of agl3 operon may facilitate the absorption of extracellular carbohydrates to balance the ratio of intracellular carbon to nitrogen. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Characterization of the Pivotal Carbon Metabolism of Streptococcus suis Serotype 2 under ex Vivo and Chemically Defined in Vitro Conditions by Isotopologue Profiling*

    Science.gov (United States)

    Willenborg, Jörg; Huber, Claudia; Koczula, Anna; Lange, Birgit; Eisenreich, Wolfgang; Valentin-Weigand, Peter; Goethe, Ralph

    2015-01-01

    Streptococcus suis is a neglected zoonotic pathogen that has to adapt to the nutritional requirements in the different host niches encountered during infection and establishment of invasive diseases. To dissect the central metabolic activity of S. suis under different conditions of nutrient availability, we performed labeling experiments starting from [13C]glucose specimens and analyzed the resulting isotopologue patterns in amino acids of S. suis grown under in vitro and ex vivo conditions. In combination with classical growth experiments, we found that S. suis is auxotrophic for Arg, Gln/Glu, His, Leu, and Trp in chemically defined medium. De novo biosynthesis was shown for Ala, Asp, Ser, and Thr at high rates and for Gly, Lys, Phe, Tyr, and Val at moderate or low rates, respectively. Glucose degradation occurred mainly by glycolysis and to a minor extent by the pentose phosphate pathway. Furthermore, the exclusive formation of oxaloacetate by phosphoenolpyruvate (PEP) carboxylation became evident from the patterns in de novo synthesized amino acids. Labeling experiments with S. suis grown ex vivo in blood or cerebrospinal fluid reflected the metabolic adaptation to these host niches with different nutrient availability; however, similar key metabolic activities were identified under these conditions. This points at the robustness of the core metabolic pathways in S. suis during the infection process. The crucial role of PEP carboxylation for growth of S. suis in the host was supported by experiments with a PEP carboxylase-deficient mutant strain in blood and cerebrospinal fluid. PMID:25575595

  8. Carbon isotopes: variations of their natural abundance. Application to correction of radiocarbon dates, to the study of plant metabolism and to paleoclimate

    International Nuclear Information System (INIS)

    Lerman, J.C.

    1974-01-01

    The radiocarbon activity of contemporaneous samples shows: i) variations in the specific activity of the atmospheric C14, which varies with time and locality. ii) variations due to isotope discrimination, or fractionation, of the carbon isotope ratio during the fixation of carbon by organic or inorganic matter. The variation in the atmospheric concentration of carbon 14 as observed in tree rings are synchronous and of the same amplitude for both hemispheres (southern and northern). A curve for correction of radiocarbon dates of the southern hemisphere is given for the last 500 years. The activity of atmospheric radiocarbon as measured in tree rings varies with latitude, showing a difference of (4.5+-1) per mille between the northern and southern hemispheres, the latter having lower concentration of radiocarbon, equivalent to an age difference of about 35 years. This variation can be explained by a larger exchange of carbon 14 between the atmosphere and the sea in the southern hemisphere to a larger free ocean surface (40%) and a higher agitation by winds. The main differences of the isotope fractionation by different types of plants are correlated to their photosynthetic pathways and thus to the enzyme which effects the primary fixation of carbon. The delta C13 values can be used as basis of a paleoclimate indicator [fr

  9. Metabolic Syndrome

    Science.gov (United States)

    Metabolic syndrome is a group of conditions that put you at risk for heart disease and diabetes. These conditions ... agree on the definition or cause of metabolic syndrome. The cause might be insulin resistance. Insulin is ...

  10. White House Unveils America's College Promise Proposal: Tuition-Free Community College for Responsible Students. Fact Sheet

    Science.gov (United States)

    The White House, 2015

    2015-01-01

    In January, 2015, the President unveiled the America's College Promise proposal, which would make two years of community college free for responsible students, letting students earn the first half of a bachelor's degree and earn skills needed in the workforce at no cost. This proposal will require everyone to do their part: community colleges must…

  11. Unveiling EFL and Self-Contained Teachers' Discourses on Bilingualism within the Context of Professional Development

    Science.gov (United States)

    Camargo Cely, Jennyfer Paola

    2018-01-01

    Throughout time, the predominant use of certain languages has allowed some nations to take control over others and assure for them a privileged position. This study unveiled how certain practices and ideologies in regard to bilingualism have influenced teachers' professional development. Data were collected through discussion group sessions,…

  12. Poly(urethane–carbonate)s from Carbon Dioxide

    KAUST Repository

    Chen, Zuliang

    2017-03-09

    A one-pot, two-step protocol for the direct synthesis of polyurethanes containing few carbonate linkages through polycondensation of diamines, dihalides, and CO2 in the presence of Cs2CO3 and tetrabutylammonium bromide is described. The conditions were optimized by studying the polycondensation of CO2 with 1,6-hexanediamine and 1,4-dibromobutane as model monomers. Then, various diamines and dihalides were tested under optimal conditions. Miscellaneous samples of such carbonate-containing polyurethanes exhibiting molar masses from 6000 to 22 000 g/mol (GPC) and yields higher than 85% were obtained. The thermal properties of such polyurethanes were unveiled by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA): they were found very similar to those of traditional polyurethanes obtained by diisocyanates + diols polycondensation.

  13. Poly(urethane–carbonate)s from Carbon Dioxide

    KAUST Repository

    Chen, Zuliang; Hadjichristidis, Nikolaos; Feng, Xiaoshuang; Gnanou, Yves

    2017-01-01

    A one-pot, two-step protocol for the direct synthesis of polyurethanes containing few carbonate linkages through polycondensation of diamines, dihalides, and CO2 in the presence of Cs2CO3 and tetrabutylammonium bromide is described. The conditions were optimized by studying the polycondensation of CO2 with 1,6-hexanediamine and 1,4-dibromobutane as model monomers. Then, various diamines and dihalides were tested under optimal conditions. Miscellaneous samples of such carbonate-containing polyurethanes exhibiting molar masses from 6000 to 22 000 g/mol (GPC) and yields higher than 85% were obtained. The thermal properties of such polyurethanes were unveiled by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA): they were found very similar to those of traditional polyurethanes obtained by diisocyanates + diols polycondensation.

  14. Unveiling non-stationary coupling between Amazon and ocean during recent extreme events

    Science.gov (United States)

    Ramos, Antônio M. de T.; Zou, Yong; de Oliveira, Gilvan Sampaio; Kurths, Jürgen; Macau, Elbert E. N.

    2018-02-01

    The interplay between extreme events in the Amazon's precipitation and the anomaly in the temperature of the surrounding oceans is not fully understood, especially its causal relations. In this paper, we investigate the climatic interaction between these regions from 1999 until 2012 using modern tools of complex system science. We identify the time scale of the coupling quantitatively and unveil the non-stationary influence of the ocean's temperature. The findings show consistently the distinctions between the coupling in the recent major extreme events in Amazonia, such as the two droughts that happened in 2005 and 2010 and the three floods during 1999, 2009 and 2012. Interestingly, the results also reveal the influence over the anomalous precipitation of Southwest Amazon has become increasingly lagged. The analysis can shed light on the underlying dynamics of the climate network system and consequently can improve predictions of extreme rainfall events.

  15. Unveiling the molecular bipolar outflow of the peculiar red supergiant VY Canis Majoris

    Science.gov (United States)

    Shinnaga, Hiroko; Claussen, Mark J.; Lim, Jeremy; Dinh-van-Trung; Tsuboi, Masato

    2003-04-01

    We carried out polarimetric spectral-line imaging of the molecular outflow of the peculiar red supergiant VY Canis Majoris in SiO J=1-0 line in the ground vibrational state, which contains highly linearly-polarized velocity components, using the Very Large Array. We succeeded in unveiling the highly linearly polarized bipolar outflow for the first time at subarcsecond spatial resolution. The results clearly show that the direction of linear polarization of the brightest maser components is parallel to the outflow axis. The results strongly suggest that the linear polarization of the SiO maser is closely related to the outflow phenomena of the star. Furthermore, the results indicate that the linear polarization observed in the optical and infrared also occur due to the outflow phenomena.

  16. The Green Bank Ammonia Survey: Unveiling the Dynamics of the Barnard 59 Star-forming Clump

    Science.gov (United States)

    Redaelli, E.; Alves, F. O.; Caselli, P.; Pineda, J. E.; Friesen, R. K.; Chacón-Tanarro, A.; Matzner, C. D.; Ginsburg, A.; Rosolowsky, E.; Keown, J.; Offner, S. S. R.; Di Francesco, J.; Kirk, H.; Myers, P. C.; Hacar, A.; Cimatti, A.; Chen, H. H.; Chen, M. C.; Lee, K. I.; Seo, Y. M.

    2017-12-01

    Understanding the early stages of star formation is a research field of ongoing development, both theoretically and observationally. In this context, molecular data have been continuously providing observational constraints on the gas dynamics at different excitation conditions and depths in the sources. We have investigated the Barnard 59 core, the only active site of star formation in the Pipe Nebula, to achieve a comprehensive view of the kinematic properties of the source. This information was derived by simultaneously fitting ammonia inversion transition lines (1, 1) and (2, 2). Our analysis unveils the imprint of protostellar feedback, such as increasing line widths, temperature, and turbulent motions in our molecular data. Combined with complementary observations of dust thermal emission, we estimate that the core is gravitationally bound following a virial analysis. If the core is not contracting, another source of internal pressure, most likely the magnetic field, is supporting it against gravitational collapse and limits its star formation efficiency.

  17. Understanding the mechanism of catalytic fast pyrolysis by unveiling reactive intermediates in heterogeneous catalysis

    Science.gov (United States)

    Hemberger, Patrick; Custodis, Victoria B. F.; Bodi, Andras; Gerber, Thomas; van Bokhoven, Jeroen A.

    2017-06-01

    Catalytic fast pyrolysis is a promising way to convert lignin into fine chemicals and fuels, but current approaches lack selectivity and yield unsatisfactory conversion. Understanding the pyrolysis reaction mechanism at the molecular level may help to make this sustainable process more economic. Reactive intermediates are responsible for product branching and hold the key to unveiling these mechanisms, but are notoriously difficult to detect isomer-selectively. Here, we investigate the catalytic pyrolysis of guaiacol, a lignin model compound, using photoelectron photoion coincidence spectroscopy with synchrotron radiation, which allows for isomer-selective detection of reactive intermediates. In combination with ambient pressure pyrolysis, we identify fulvenone as the central reactive intermediate, generated by catalytic demethylation to catechol and subsequent dehydration. The fulvenone ketene is responsible for the phenol formation. This technique may open unique opportunities for isomer-resolved probing in catalysis, and holds the potential for achieving a mechanistic understanding of complex, real-life catalytic processes.

  18. Influence of net ecosystem metabolism in transferring riverine organic carbon to atmospheric CO2 in a tropical coastal lagoon (Chilka Lake, India)

    Digital Repository Service at National Institute of Oceanography (India)

    Gupta, G.V.M.; Sarma, V.V.S.S.; Robin, R.S.; Raman, A.V.; JaiKumar, M.; Rakesh, M.; Subramanian, B.R.

    in monsoon was contributed by its supply from rivers and the rest was contributed by in situ heterotrophic activity. Based on oxygen and total carbon mass balance, net ecosystem production (NEP) of lake (- 308 mmolC m sup(-2) d sup(-1) approx. equal to - 3...

  19. Metabolite secretion in microorganisms: the theory of metabolic overflow put to the test

    DEFF Research Database (Denmark)

    Pinu, Farhana R.; Granucci, Ninna; Daniell, James

    2018-01-01

    Introduction Microbial cells secrete many metabolites during growth, including important intermediates of the central carbon metabolism. This has not been taken into account by researchers when modeling microbial metabolism for metabolic engineering and systems biology studies. Materials and Meth...

  20. Effects of long-term (10 years) exposure to elevated CO2 and O3 on trembling Aspen carbon and nitrogen metabolism at the aspen FACE (Free-Air Carbon Dioxide Enrichment) study site

    Science.gov (United States)

    Rakesh Minocha; Stephanie Long; Subhash Minocha; Paula Marquardt; Neil Nelson; Mark. Kubiske

    2010-01-01

    This study was conducted at the Aspen Free-Air Carbon Dioxide Enrichment (FACE) experimental site, Rhinelander, WI, (USA). Since 1998, 12 experimental rings planted in 1997 underwent four different treatments: control; elevated CO2 (560 ppm); elevated O3 (1.5X ambient) and elevated CO2 (560 ppm) + O...

  1. Body Covering and Body Image: A Comparison of Veiled and Unveiled Muslim Women, Christian Women, and Atheist Women Regarding Body Checking, Body Dissatisfaction, and Eating Disorder Symptoms.

    Science.gov (United States)

    Wilhelm, Leonie; Hartmann, Andrea S; Becker, Julia C; Kişi, Melahat; Waldorf, Manuel; Vocks, Silja

    2018-02-21

    Although Islam is the fastest growing religion worldwide, only few studies have investigated body image in Muslim women, and no study has investigated body checking. Therefore, the present study examined whether body image, body checking, and disordered eating differ between veiled and unveiled Muslim women, Christian women, and atheist women. While the groups did not differ regarding body dissatisfaction, unveiled Muslim women reported more checking than veiled Muslim and Christian women, and higher bulimia scores than Christian. Thus, prevention against eating disorders should integrate all women, irrespective of religious affiliation or veiling, with a particular focus on unveiled Muslim women.

  2. The NQO1 bioactivatable drug, β-lapachone, alters the redox state of NQO1+ pancreatic cancer cells, causing perturbation in central carbon metabolism.

    Science.gov (United States)

    Silvers, Molly A; Deja, Stanislaw; Singh, Naveen; Egnatchik, Robert A; Sudderth, Jessica; Luo, Xiuquan; Beg, Muhammad S; Burgess, Shawn C; DeBerardinis, Ralph J; Boothman, David A; Merritt, Matthew E

    2017-11-03

    Many cancer treatments, such as those for managing recalcitrant tumors like pancreatic ductal adenocarcinoma, cause off-target toxicities in normal, healthy tissue, highlighting the need for more tumor-selective chemotherapies. β-Lapachone is bioactivated by NAD(P)H:quinone oxidoreductase 1 (NQO1). This enzyme exhibits elevated expression in most solid cancers and therefore is a potential cancer-specific target. β-Lapachone's therapeutic efficacy partially stems from the drug's induction of a futile NQO1-mediated redox cycle that causes high levels of superoxide and then peroxide formation, which damages DNA and causes hyperactivation of poly(ADP-ribose) polymerase, resulting in extensive NAD + /ATP depletion. However, the effects of this drug on energy metabolism due to NAD + depletion were never described. The futile redox cycle rapidly consumes O 2 , rendering standard assays of Krebs cycle turnover unusable. In this study, a multimodal analysis, including metabolic imaging using hyperpolarized pyruvate, points to reduced oxidative flux due to NAD + depletion after β-lapachone treatment of NQO1+ human pancreatic cancer cells. NAD + -sensitive pathways, such as glycolysis, flux through lactate dehydrogenase, and the citric acid cycle (as inferred by flux through pyruvate dehydrogenase), were down-regulated by β-lapachone treatment. Changes in flux through these pathways should generate biomarkers useful for in vivo dose responses of β-lapachone treatment in humans, avoiding toxic side effects. Targeting the enzymes in these pathways for therapeutic treatment may have the potential to synergize with β-lapachone treatment, creating unique NQO1-selective combinatorial therapies for specific cancers. These findings warrant future studies of intermediary metabolism in patients treated with β-lapachone. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  3. Metabolism of sulfate-reducing bacteria and corrosion behavior of carbon steel in the continuous culturing medium; Renzoku baiyo baichichu ni okeru ryusan`en kangen no taisha to tansoko no fushoku kyodo

    Energy Technology Data Exchange (ETDEWEB)

    Baba, F.; Suzuki, T. [Ajinomoto Co. Inc., Tokyo (Japan); Seo, M. [Hokkaido University, Sapporo (Japan)

    1997-08-25

    Investigations were made on metabolism of sulfate-reducing bacteria and corrosion behavior of carbon steel in the continuous culturing medium. Sulfate-reducing bacteria were cultured for 50 days by supplying the culturing medium prepared to a prescribed chemical composition (containing Fe {sup 2+} at 0.01 mol/kg) at a rate of 10 cm {sup 3}/h, and drawing them out at the same rate. Test carbon steel pieces were immersed into this culturing medium. As a result, the following matters were clarified: the number of bacteria is maintained at more than 10 {sup 10}/cm{sup 3} after several days since inauguration of the immersion, with the bacteria stably producing H2S and FeS until the culturing is finished; comma-shaped bacteria which move actively and rod-shaped bacteria which do not move very actively exist in the culturing medium; a black film has been produced on surface of the test pieces throughout the culturing period, and satin-like corrosion was found underneath the surface; and weight increase of this film and weight decrease of the lower layer progress as the time lapses (the weight decrease of the lower layer has reached 40 mg/cm{sup 2} in 50 days). 28 refs., 8 figs., 1 tab.

  4. Potential use of carbon-11 labeled alpha-aminoisobutyric acid (AIB) as an in vivo tracer of amino acid uptake in differing metabolic states

    International Nuclear Information System (INIS)

    Conti, P.S.; Starnes, H.F.; Brennan, M.F.

    1986-01-01

    AIB has been used as a model amino acid for the evaluation of alanine-preferring amino acid transport. Hormonal factors and starvation alter the tissue distribution of amino acids, particularly in liver and muscle. With positron emission tomography and labeling of biochemical tracers with C-11, (t1/2=20.4 min), it is now possible to study amino acid kinetics in vivo using external imaging. In order to investigate the utility of C-11 AIB as an in vivo tracer of altered tissue metabolism, C-14 AIB was studied in groups of rats with either streptozotocin-induced diabetes, insulin-induced hypoglycemia or starvation. The data suggest an increased amino acid uptake in liver in starvation, an increased uptake in muscle in response to insulin and associated hypoglycemia and decreased transport in muscle in starvation, as seen by other investigators. These results suggest that C-11 AIB may be useful as an in vivo monitor of metabolic changes in body tissues

  5. Carbon-14 tracer studies in the metabolism of isolated rat-liver parenchymal cells under conditions of gluconeogenesis from lactate and pyruvate

    International Nuclear Information System (INIS)

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

    1977-01-01

    In rat liver perfusion experiments under conditions of gluconeogenesis from lactate and pyruvate, 14 C-labeling patterns of metabolites with (1- 14 C)-labeled and (2- 14 C)-labeled lactate or pyruvate. [ 14 C]bicarbonate and [1- 14 C]octanoate as tracers have been obtained which do not agree with generally assumed reaction schemes. The experiments have been repeated with incubations of isolated rat-liver parenchymal cells. The results demonstrate that the discrepancies between expected and analysed 14 C-labeling patterns of metabolites were still existent. From this observation, it may be concluded that 14 C-labelling patterns of metabolites are indicative for the existence of still unknown metabolic relationships in liver parenchymal cells. Furthermore, the results of our experiments prove that conclusions based on the exclusive analysis of metabolite levels are of limited value for studying intracellular events, because of uncharacterized compartmentations, which become evident in 14 C-tracer studies. It cannot be answered by our studies whether the apparent existence of differently labelled species of citrate, oxoglutarate, or acetyl-CoA represent intracellular compartmentation, or whether it is the result of metabolic heterogeneity of liver parenchym cells. (orig.) [de

  6. Deficiency in L-serine deaminase interferes with one-carbon metabolism and cell wall synthesis in Escherichia coli K-12.

    Science.gov (United States)

    Zhang, Xiao; El-Hajj, Ziad W; Newman, Elaine

    2010-10-01

    Escherichia coli K-12 provided with glucose and a mixture of amino acids depletes L-serine more quickly than any other amino acid even in the presence of ammonium sulfate. A mutant without three 4Fe4S L-serine deaminases (SdaA, SdaB, and TdcG) of E. coli K-12 is unable to do this. The high level of L-serine that accumulates when such a mutant is exposed to amino acid mixtures starves the cells for C(1) units and interferes with cell wall synthesis. We suggest that at high concentrations, L-serine decreases synthesis of UDP-N-acetylmuramate-L-alanine by the murC-encoded ligase, weakening the cell wall and producing misshapen cells and lysis. The inhibition by high L-serine is overcome in several ways: by a large concentration of L-alanine, by overproducing MurC together with a low concentration of L-alanine, and by overproducing FtsW, thus promoting septal assembly and also by overexpression of the glycine cleavage operon. S-Adenosylmethionine reduces lysis and allows an extensive increase in biomass without improving cell division. This suggests that E. coli has a metabolic trigger for cell division. Without that reaction, if no other inhibition occurs, other metabolic functions can continue and cells can elongate and replicate their DNA, reaching at least 180 times their usual length, but cannot divide.

  7. Deficiency in l-Serine Deaminase Interferes with One-Carbon Metabolism and Cell Wall Synthesis in Escherichia coli K-12▿

    Science.gov (United States)

    Zhang, Xiao; El-Hajj, Ziad W.; Newman, Elaine

    2010-01-01

    Escherichia coli K-12 provided with glucose and a mixture of amino acids depletes l-serine more quickly than any other amino acid even in the presence of ammonium sulfate. A mutant without three 4Fe4S l-serine deaminases (SdaA, SdaB, and TdcG) of E. coli K-12 is unable to do this. The high level of l-serine that accumulates when such a mutant is exposed to amino acid mixtures starves the cells for C1 units and interferes with cell wall synthesis. We suggest that at high concentrations, l-serine decreases synthesis of UDP-N-acetylmuramate-l-alanine by the murC-encoded ligase, weakening the cell wall and producing misshapen cells and lysis. The inhibition by high l-serine is overcome in several ways: by a large concentration of l-alanine, by overproducing MurC together with a low concentration of l-alanine, and by overproducing FtsW, thus promoting septal assembly and also by overexpression of the glycine cleavage operon. S-Adenosylmethionine reduces lysis and allows an extensive increase in biomass without improving cell division. This suggests that E. coli has a metabolic trigger for cell division. Without that reaction, if no other inhibition occurs, other metabolic functions can continue and cells can elongate and replicate their DNA, reaching at least 180 times their usual length, but cannot divide. PMID:20729359

  8. Methionine and Choline Supply during the Periparturient Period Alter Plasma Amino Acid and One-Carbon Metabolism Profiles to Various Extents: Potential Role in Hepatic Metabolism and Antioxidant Status

    Directory of Open Access Journals (Sweden)

    Zheng Zhou

    2016-12-01

    Full Text Available The objective of this study was to profile plasma amino acids (AA and derivatives of their metabolism during the periparturient period in response to supplemental rumen-protected methionine (MET or rumen-protected choline (CHOL. Forty cows were fed from −21 through 30 days around parturition in a 2 × 2 factorial design a diet containing MET or CHOL. MET supply led to greater circulating methionine and proportion of methionine in the essential AA pool, total AA, and total sulfur-containing compounds. Lysine in total AA also was greater in these cows, indicating a better overall AA profile. Sulfur-containing compounds (cystathionine, cystine, homocystine, and taurine were greater in MET-fed cows, indicating an enriched sulfur-containing compound pool due to enhanced transsulfuration activity. Circulating essential AA and total AA concentrations were greater in cows supplied MET due to greater lysine, arginine, tryptophan, threonine, proline, asparagine, alanine, and citrulline. In contrast, CHOL supply had no effect on essential AA or total AA, and only tryptophan and cystine were greater. Plasma 3-methylhistidine concentration was lower in response to CHOL supply, suggesting less tissue protein mobilization in these cows. Overall, the data revealed that enhanced periparturient supply of MET has positive effects on plasma AA profiles and overall antioxidant status.

  9. Determination of Krebs cycle metabolic carbon exchange in vivo and its use to estimate the individual contributions of gluconeogenesis and glycogenolysis to overall glucose output in man

    International Nuclear Information System (INIS)

    Consoli, A.; Kennedy, F.; Miles, J.; Gerich, J.

    1987-01-01

    Current isotopic approaches underestimate gluconeogenesis in vivo because of Krebs cycle carbon exchange and the inability to measure intramitochondrial precursor specific activity. We therefore applied a new isotopic approach that theoretically overcomes these limitations and permits quantification of Krebs cycle carbon exchange and the individual contributions of gluconeogenesis and glycogenolysis to overall glucose outputex. [6-3H]Glucose was infused to measure overall glucose output; [2-14C]acetate was infused to trace phosphoenolpyruvate gluconeogenesis and to calculate Krebs cycle carbon exchange as proposed by Katz. Plasma [14C]3-OH-butyrate specific activity was used to estimate intramitochondrial acetyl coenzyme A (CoA) specific activity, and finally the ratio between plasma glucose 14C-specific activity and the calculated intracellular phosphoenolpyruvate 14C-specific activity was used to determine the relative contributions of gluconeogenesis and glycogenolysis to overall glucose output. Using this approach, acetyl CoA was found to enter the Krebs cycle at twice (postabsorptive subjects) and three times (2 1/2-d fasted subjects) the rate of pyruvate, respectively. Gluconeogenesis in postabsorptive subjects (3.36 +/- 0.20 mumol/kg per min) accounted for 28 +/- 2% of overall glucose output and increased twofold in subjects fasted for 2 1/2-d (P less than 0.01), accounting for greater than 97% of overall glucose output. Glycogenolysis in postabsorptive subjects averaged 8.96 +/- 0.40 mumol/kg per min and decreased to 0.34 +/- 0.08 mumol/kg per min (P less than 0.01) after a 2 1/2-d fast. Since these results agree well with previously reported values for gluconeogenesis and glycogenolysis based on determinations of splanchnic substrate balance and glycogen content of serial liver biopsies

  10. Urban metabolism: A review of research methodologies

    International Nuclear Information System (INIS)

    Zhang, Yan

    2013-01-01

    Urban metabolism analysis has become an important tool for the study of urban ecosystems. The problems of large metabolic throughput, low metabolic efficiency, and disordered metabolic processes are a major cause of unhealthy urban systems. In this paper, I summarize the international research on urban metabolism, and describe the progress that has been made in terms of research methodologies. I also review the methods used in accounting for and evaluating material and energy flows in urban metabolic processes, simulation of these flows using a network model, and practical applications of these methods. Based on this review of the literature, I propose directions for future research, and particularly the need to study the urban carbon metabolism because of the modern context of global climate change. Moreover, I recommend more research on the optimal regulation of urban metabolic systems. Highlights: •Urban metabolic processes can be analyzed by regarding cities as superorganisms. •Urban metabolism methods include accounting, assessment, modeling, and regulation. •Research methodologies have improved greatly since this field began in 1965. •Future research should focus on carbon metabolism and optimal regulation. -- The author reviews research progress in the field of urban metabolism, and based on her literature review, proposes directions for future research

  11. What is Metabolic Syndrome?

    Science.gov (United States)

    ... Intramural Research Home / Metabolic Syndrome Metabolic Syndrome Also known as What Is Metabolic syndrome ... metabolic risk factors to be diagnosed with metabolic syndrome. Metabolic Risk Factors A Large Waistline Having a large ...

  12. The Aspergillus nidulans acuL gene encodes a mitochondrial carrier required for the utilization of carbon sources that are metabolized via the TCA cycle.

    Science.gov (United States)

    Flipphi, Michel; Oestreicher, Nathalie; Nicolas, Valérie; Guitton, Audrey; Vélot, Christian

    2014-07-01

    In Aspergillus nidulans, the utilization of acetate as sole carbon source requires several genes (acu). Most of them are also required for the utilization of fatty acids. This is the case for acuD and acuE, which encode the two glyoxylate cycle-specific enzymes, isocitrate lyase and malate synthase, respectively, but also for acuL that we have identified as AN7287, and characterized in this study. Deletion of acuL resulted in the same phenotype as the original acuL217 mutant. acuL encodes a 322-amino acid protein which displays all the structural features of a mitochondrial membrane carrier, and shares 60% identity with the Saccharomyces cerevisiae succinate/fumarate mitochondrial antiporter Sfc1p (also named Acr1p). Consistently, the AcuL protein was shown to localize in mitochondria, and partial cross-complementation was observed between the S. cerevisiae and A. nidulans homologues. Extensive phenotypic characterization suggested that the acuL gene is involved in the utilization of carbon sources that are catabolized via the TCA cycle, and therefore require gluconeogenesis. In addition, acuL proves to be co-regulated with acuD and acuE. Overall, our data suggest that AcuL could link the glyoxylate cycle to gluconeogenesis by exchanging cytoplasmic succinate for mitochondrial fumarate. Copyright © 2014 Elsevier Inc. All rights reserved.

  13. Microbial Development and Metabolic Engineering | Bioenergy | NREL

    Science.gov (United States)

    Diversity Our genetically engineered microbes utilize a variety of feedstock including cellulose, xylan , syngas, simple sugars, organic acids, and carbon dioxide (CO2). We have modified the metabolic pathways

  14. Rewiring monocyte glucose metabolism via C-type lectin signaling protects against disseminated candidiasis.

    Science.gov (United States)

    Domínguez-Andrés, Jorge; Arts, Rob J W; Ter Horst, Rob; Gresnigt, Mark S; Smeekens, Sanne P; Ratter, Jacqueline M; Lachmandas, Ekta; Boutens, Lily; van de Veerdonk, Frank L; Joosten, Leo A B; Notebaart, Richard A; Ardavín, Carlos; Netea, Mihai G

    2017-09-01

    Monocytes are innate immune cells that play a pivotal role in antifungal immunity, but little is known regarding the cellular metabolic events that regulate their function during infection. Using complementary transcriptomic and immunological studies in human primary monocytes, we show that activation of monocytes by Candida albicans yeast and hyphae was accompanied by metabolic rewiring induced through C-type lectin-signaling pathways. We describe that the innate immune responses against Candida yeast are energy-demanding processes that lead to the mobilization of intracellular metabolite pools and require induction of glucose metabolism, oxidative phosphorylation and glutaminolysis, while responses to hyphae primarily rely on glycolysis. Experimental models of systemic candidiasis models validated a central role for glucose metabolism in anti-Candida immunity, as the impairment of glycolysis led to increased susceptibility in mice. Collectively, these data highlight the importance of understanding the complex network of metabolic responses triggered during infections, and unveil new potential targets for therapeutic approaches against fungal diseases.

  15. Integration of metabolic and gene regulatory networks modulates the C. elegans dietary response.

    Science.gov (United States)

    Watson, Emma; MacNeil, Lesley T; Arda, H Efsun; Zhu, Lihua Julie; Walhout, Albertha J M

    2013-03-28

    Expression profiles are tailored according to dietary input. However, the networks that control dietary responses remain largely uncharacterized. Here, we combine forward and reverse genetic screens to delineate a network of 184 genes that affect the C. elegans dietary response to Comamonas DA1877 bacteria. We find that perturbation of a mitochondrial network composed of enzymes involved in amino acid metabolism and the TCA cycle affects the dietary response. In humans, mutations in the corresponding genes cause inborn diseases of amino acid metabolism, most of which are treated by dietary intervention. We identify several transcription factors (TFs) that mediate the changes in gene expression upon metabolic network perturbations. Altogether, our findings unveil a transcriptional response system that is poised to sense dietary cues and metabolic imbalances, illustrating extensive communication between metabolic networks in the mitochondria and gene regulatory networks in the nucleus. Copyright © 2013 Elsevier Inc. All rights reserved.

  16. Bile Acid Signaling in Metabolic Disease and Drug Therapy

    Science.gov (United States)

    Li, Tiangang

    2014-01-01

    Bile acids are the end products of cholesterol catabolism. Hepatic bile acid synthesis accounts for a major fraction of daily cholesterol turnover in humans. Biliary secretion of bile acids generates bile flow and facilitates hepatobiliary secretion of lipids, lipophilic metabolites, and xenobiotics. In the intestine, bile acids are essential for the absorption, transport, and metabolism of dietary fats and lipid-soluble vitamins. Extensive research in the last 2 decades has unveiled new functions of bile acids as signaling molecules and metabolic integrators. The bile acid–activated nuclear receptors farnesoid X receptor, pregnane X receptor, constitutive androstane receptor, vitamin D receptor, and G protein–coupled bile acid receptor play critical roles in the regulation of lipid, glucose, and energy metabolism, inflammation, and drug metabolism and detoxification. Bile acid synthesis exhibits a strong diurnal rhythm, which is entrained by fasting and refeeding as well as nutrient status and plays an important role for maintaining metabolic homeostasis. Recent research revealed an interaction of liver bile acids and gut microbiota in the regulation of liver metabolism. Circadian disturbance and altered gut microbiota contribute to the pathogenesis of liver diseases, inflammatory bowel diseases, nonalcoholic fatty liver disease, diabetes, and obesity. Bile acids and their derivatives are potential therapeutic agents for treating metabolic diseases of the liver. PMID:25073467

  17. Codon-triplet context unveils unique features of the Candida albicans protein coding genome

    Directory of Open Access Journals (Sweden)

    Oliveira José L

    2007-11-01

    Full Text Available Abstract Background The evolutionary forces that determine the arrangement of synonymous codons within open reading frames and fine tune mRNA translation efficiency are not yet understood. In order to tackle this question we have carried out a large scale study of codon-triplet contexts in 11 fungal species to unravel associations or relationships between codons present at the ribosome A-, P- and E-sites during each decoding cycle. Results Our analysis unveiled high bias within the context of codon-triplets, in particular strong preference for triplets of identical codons. We have also identified a surprisingly large number of codon-triplet combinations that vanished from fungal ORFeomes. Candida albicans exacerbated these features, showed an unbalanced tRNA population for decoding its pool of codons and used near-cognate decoding for a large set of codons, suggesting that unique evolutionary forces shaped the evolution of its ORFeome. Conclusion We have developed bioinformatics tools for large-scale analysis of codon-triplet contexts. These algorithms identified codon-triplets context biases, allowed for large scale comparative codon-triplet analysis, and identified rules governing codon-triplet context. They could also detect alterations to the standard genetic code.

  18. A strategy to unveil transient sources of ultra-high-energy cosmic rays

    Directory of Open Access Journals (Sweden)

    Takami Hajime

    2013-06-01

    Full Text Available Transient generation of ultra-high-energy cosmic rays (UHECRs has been motivated from promising candidates of UHECR sources such as gamma-ray bursts, flares of active galactic nuclei, and newly born neutron stars and magnetars. Here we propose a strategy to unveil transient sources of UHECRs from UHECR experiments. We demonstrate that the rate of UHECR bursts and/or flares is related to the apparent number density of UHECR sources, which is the number density estimated on the assumption of steady sources, and the time-profile spread of the bursts produced by cosmic magnetic fields. The apparent number density strongly depends on UHECR energies under a given rate of the bursts, which becomes observational evidence of transient sources. It is saturated at the number density of host galaxies of UHECR sources. We also derive constraints on the UHECR burst rate and/or energy budget of UHECRs per source as a function of the apparent source number density by using models of cosmic magnetic fields. In order to obtain a precise constraint of the UHECR burst rate, high event statistics above ∼ 1020 eV for evaluating the apparent source number density at the highest energies and better knowledge on cosmic magnetic fields by future observations and/or simulations to better estimate the time-profile spread of UHECR bursts are required. The estimated rate allows us to constrain transient UHECR sources by being compared with the occurrence rates of known energetic transient phenomena.

  19. Surprisal analysis of Glioblastoma Multiform (GBM) microRNA dynamics unveils tumor specific phenotype.

    Science.gov (United States)

    Zadran, Sohila; Remacle, Francoise; Levine, Raphael

    2014-01-01

    Gliomablastoma multiform (GBM) is the most fatal form of all brain cancers in humans. Currently there are limited diagnostic tools for GBM detection. Here, we applied surprisal analysis, a theory grounded in thermodynamics, to unveil how biomolecule energetics, specifically a redistribution of free energy amongst microRNAs (miRNAs), results in a system deviating from a non-cancer state to the GBM cancer -specific phenotypic state. Utilizing global miRNA microarray expression data of normal and GBM patients tumors, surprisal analysis characterizes a miRNA system response capable of distinguishing GBM samples from normal tissue biopsy samples. We indicate that the miRNAs contributing to this system behavior is a disease phenotypic state specific to GBM and is therefore a unique GBM-specific thermodynamic signature. MiRNAs implicated in the regulation of stochastic signaling processes crucial in the hallmarks of human cancer, dominate this GBM-cancer phenotypic state. With this theory, we were able to distinguish with high fidelity GBM patients solely by monitoring the dynamics of miRNAs present in patients' biopsy samples. We anticipate that the GBM-specific thermodynamic signature will provide a critical translational tool in better characterizing cancer types and in the development of future therapeutics for GBM.

  20. Unveiling the water-associated conformational mobility in the active site of ascorbate peroxidase.

    Science.gov (United States)

    Chao, Wei-Chih; Lin, Li-Ju; Lu, Jyh-Feng; Wang, Jinn-Shyan; Lin, Tzu-Chieh; Chen, Yi-Han; Chen, Yi-Ting; Yang, Hsiao-Ching; Chou, Pi-Tai

    2018-03-01

    We carried out comprehensive spectroscopic studies of wild type and mutants of ascorbate peroxidase (APX) to gain understanding of the conformational mobility of the active site. In this approach, three unnatural tryptophans were applied to replace the distal tryptophan (W41) in an aim to probe polarity/water environment near the edge of the heme-containing active site. 7-azatryptophan ((7-aza)Trp) is sensitive to environment polarity, while 2,7-azatryptophan ((2,7-aza)Trp) and 2,6-diazatryptophan ((2,6-aza)Trp) undergo excited-state water-catalyzed double and triple proton transfer, respectively, and are sensitive to the water network. The combination of their absorption, emission bands and the associated relaxation dynamics of these fluorescence probes, together with the Soret-band difference absorption and resonance Raman spectroscopy, lead us to unveil the water associated conformational mobility in the active site of APX. The results are suggestive of the existence of equilibrium between two different environments surrounding W41 in APX, i.e., the water-rich and water-scant forms with distinct fluorescence relaxation. Our results thus demonstrate for the first time the power of integrating multiple sensors (7-aza)Trp, (2,7-aza)Trp and (2,6-aza)Trp in probing the water environment of a specifically targeted Trp in proteins. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Cellular therapies for heart disease: unveiling the ethical and public policy challenges.

    Science.gov (United States)

    Raval, Amish N; Kamp, Timothy J; Hogle, Linda F

    2008-10-01

    Cellular therapies have emerged as a potential revolutionary treatment for cardiovascular disease. Promising preclinical results have resulted in a flurry of basic research activity and spawned multiple clinical trials worldwide. However, the optimal cell type and delivery mode have not been determined for target patient populations. Nor have the mechanisms of benefit for the range of cellular interventions been clearly defined. Experiences to date have unveiled a myriad of ethical and public policy challenges which will affect the way researchers and clinicians make decisions for both basic and clinical research. Stem cells derived from embryos are at the forefront of the ethical and political debate, raising issues of which derivation methods are morally and socially permissible to pursue, as much as which are technically feasible. Adult stem cells are less controversial; however, important challenges exist in determining study design, cell processing, delivery mode, and target patient population. Pathways to successful commercialization and hence broad accessibility of cellular therapies for heart disease are only beginning to be explored. Comprehensive, multi-disciplinary and collaborative networks involving basic researchers, clinicians, regulatory officials and policymakers are required to share information, develop research, regulatory and policy standards and enable rational and ethical cell-based treatment approaches.

  2. Unveiling the geography of historical patents in the United States from 1836 to 1975

    Science.gov (United States)

    Petralia, Sergio; Balland, Pierre-Alexandre; Rigby, David L.

    2016-01-01

    It is clear that technology is a key driver of economic growth. Much less clear is where new technologies are produced and how the geography of U.S. invention has changed over the last two hundred years. Patent data report the geography, history, and technological characteristics of invention. However, those data have only recently become available in digital form and at the present time there exists no comprehensive dataset on the geography of knowledge production in the United States prior to 1975. The database presented in this paper unveils the geography of historical patents granted by the United States Patent and Trademark Office (USPTO) from 1836 to 1975. This historical dataset, HistPat, is constructed using digitalized records of original patent documents that are publicly available. We describe a methodological procedure that allows recovery of geographical information on patents from the digital records. HistPat can be used in different disciplines ranging from geography, economics, history, network science, and science and technology studies. Additionally, it is easily merged with post-1975 USPTO digital patent data to extend it until today. PMID:27576103

  3. Unveiling the development of intracranial injury using dynamic brain EIT: an evaluation of current reconstruction algorithms.

    Science.gov (United States)

    Li, Haoting; Chen, Rongqing; Xu, Canhua; Liu, Benyuan; Tang, Mengxing; Yang, Lin; Dong, Xiuzhen; Fu, Feng

    2017-08-21

    Dynamic brain electrical impedance tomography (EIT) is a promising technique for continuously monitoring the development of cerebral injury. While there are many reconstruction algorithms available for brain EIT, there is still a lack of study to compare their performance in the context of dynamic brain monitoring. To address this problem, we develop a framework for evaluating different current algorithms with their ability to correctly identify small intracranial conductivity changes. Firstly, a simulation 3D head phantom with realistic layered structure and impedance distribution is developed. Next several reconstructing algorithms, such as back projection (BP), damped least-square (DLS), Bayesian, split Bregman (SB) and GREIT are introduced. We investigate their temporal response, noise performance, location and shape error with respect to different noise levels on the simulation phantom. The results show that the SB algorithm demonstrates superior performance in reducing image error. To further improve the location accuracy, we optimize SB by incorporating the brain structure-based conductivity distribution priors, in which differences of the conductivities between different brain tissues and the inhomogeneous conductivity distribution of the skull are considered. We compare this novel algorithm (called SB-IBCD) with SB and DLS using anatomically correct head shaped phantoms with spatial varying skull conductivity. Main results and Significance: The results showed that SB-IBCD is the most effective in unveiling small intracranial conductivity changes, where it can reduce the image error by an average of 30.0% compared to DLS.

  4. Intermediary metabolism in protists: a sequence-based view of facultative anaerobic metabolism in evolutionarily diverse eukaryotes.

    Science.gov (United States)

    Ginger, Michael L; Fritz-Laylin, Lillian K; Fulton, Chandler; Cande, W Zacheus; Dawson, Scott C

    2010-12-01

    Protists account for the bulk of eukaryotic diversity. Through studies of gene and especially genome sequences the molecular basis for this diversity can be determined. Evident from genome sequencing are examples of versatile metabolism that go far beyond the canonical pathways described for eukaryotes in textbooks. In the last 2-3 years, genome sequencing and transcript profiling has unveiled several examples of heterotrophic and phototrophic protists that are unexpectedly well-equipped for ATP production using a facultative anaerobic metabolism, including some protists that can (Chlamydomonas reinhardtii) or are predicted (Naegleria gruberi, Acanthamoeba castellanii, Amoebidium parasiticum) to produce H(2) in their metabolism. It is possible that some enzymes of anaerobic metabolism were acquired and distributed among eukaryotes by lateral transfer, but it is also likely that the common ancestor of eukaryotes already had far more metabolic versatility than was widely thought a few years ago. The discussion of core energy metabolism in unicellular eukaryotes is the subject of this review. Since genomic sequencing has so far only touched the surface of protist diversity, it is anticipated that sequences of additional protists may reveal an even wider range of metabolic capabilities, while simultaneously enriching our understanding of the early evolution of eukaryotes. Copyright © 2010 Elsevier GmbH. All rights reserved.

  5. [Metabolic acidosis].

    Science.gov (United States)

    Regolisti, Giuseppe; Fani, Filippo; Antoniotti, Riccardo; Castellano, Giuseppe; Cremaschi, Elena; Greco, Paolo; Parenti, Elisabetta; Morabito, Santo; Sabatino, Alice; Fiaccadori, Enrico

    2016-01-01

    Metabolic acidosis is frequently observed in clinical practice, especially among critically ill patients and/or in the course of renal failure. Complex mechanisms are involved, in most cases identifiable by medical history, pathophysiology-based diagnostic reasoning and measure of some key acid-base parameters that are easily available or calculable. On this basis the bedside differential diagnosis of metabolic acidosis should be started from the identification of the two main subtypes of metabolic acidosis: the high anion gap metabolic acidosis and the normal anion gap (or hyperchloremic) metabolic acidosis. Metabolic acidosis, especially in its acute forms with elevated anion gap such as is the case of lactic acidosis, diabetic and acute intoxications, may significantly affect metabolic body homeostasis and patients hemodynamic status, setting the stage for true medical emergencies. The therapeutic approach should be first aimed at early correction of concurrent clinical problems (e.g. fluids and hemodynamic optimization in case of shock, mechanical ventilation in case of concomitant respiratory failure, hemodialysis for acute intoxications etc.), in parallel to the formulation of a diagnosis. In case of severe acidosis, the administration of alkalizing agents should be carefully evaluated, taking into account the risk of side effects, as well as the potential need of renal replacement therapy.

  6. Drought-Induced Effects on Nitrate Reductase Activity and mRNA and on the Coordination of Nitrogen and Carbon Metabolism in Maize Leaves1

    Science.gov (United States)

    Foyer, Christine H.; Valadier, Marie-Hélène; Migge, Andrea; Becker, Thomas W.

    1998-01-01

    Maize (Zea mays L.) plants were grown to the nine-leaf stage. Despite a saturating N supply, the youngest mature leaves (seventh position on the stem) contained little NO3− reserve. Droughted plants (deprived of nutrient solution) showed changes in foliar enzyme activities, mRNA accumulation, photosynthesis, and carbohydrate and amino acid contents. Total leaf water potential and CO2 assimilation rates, measured 3 h into the photoperiod, decreased 3 d after the onset of drought. Starch, glucose, fructose, and amino acids, but not sucrose (Suc), accumulated in the leaves of droughted plants. Maximal extractable phosphoenolpyruvate carboxylase activities increased slightly during water deficit, whereas the sensitivity of this enzyme to the inhibitor malate decreased. Maximal extractable Suc phosphate synthase activities decreased as a result of water stress, and there was an increase in the sensitivity to the inhibitor orthophosphate. A correlation between maximal extractable foliar nitrate reductase (NR) activity and the rate of CO2 assimilation was observed. The NR activation state and maximal extractable NR activity declined rapidly in response to drought. Photosynthesis and NR activity recovered rapidly when nutrient solution was restored at this point. The decrease in maximal extractable NR activity was accompanied by a decrease in NR transcripts, whereas Suc phosphate synthase and phosphoenolpyruvate carboxylase mRNAs were much less affected. The coordination of N and C metabolism is retained during drought conditions via modulation of the activities of Suc phosphate synthase and NR commensurate with the prevailing rate of photosynthesis. PMID:9576798

  7. C/sub 4/ photosynthesis in Euphorbia degeneri and E. remyi: a comparison of photosynthetic carbon metabolism in leaves, callus cultures and regenerated plants

    Energy Technology Data Exchange (ETDEWEB)

    Ruzin, S.E.

    1984-04-01

    Based on analysis of /sup 14/CO/sub 2/ fixation kinetics and assays of enzymes related to C/sub 4/ metabolism (NAD-ME, NADP-ME, NAD-MDH, NADP-MDH, AST, ALT), leaves and regenerated plants of Euphorbia degeneri exhibit a modified NADP-ME-type photosynthesis. Apparently, both aspartate and malate are used for transport of CO/sub 2/ to bundle sheath cells. Callus grown on either non-shoot-forming or shoot-forming media fixes CO/sub 2/ into RPP-cycle intermediates and sucrose, as well as malate and aspartate. /sup 14/CO/sub 2/ pulse/chase kinetics show no significant loss of label from C/sub 4/ acids throughout a one minute chase. Analysis of PEPCase revealed the presence of 2 isoenzymes in both leaf and regenerated plant tissues (K/sub m/ (PEP) = 0.080 and 0.550) but only one isoenzyme in callus (K/sub m/ = 0.100). It appears that C/sub 4/ photosynthesis does not occur in callus derived from this C/sub 4/ dicot but is regenerated concomitant with shoot regeneration, and ..beta..-carboxylation of PEP in callus, mediated by the low K/sub m/ isoenzyme of PEPCase, produces C/sub 4/ acids that are not involved in the CO/sub 2/ shuttle mechanism characteristic of C/sub 4/ photosynthesis. 161 references, 19 figures, 12 tables.

  8. C4 photosynthesis in Euphorbia degeneri and E. remyi: a comparison of photosynthetic carbon metabolism in leaves, callus cultures and regenerated plants

    International Nuclear Information System (INIS)

    Ruzin, S.E.

    1984-04-01

    Based on analysis of 14 CO 2 fixation kinetics and assays of enzymes related to C 4 metabolism (NAD-ME, NADP-ME, NAD-MDH, NADP-MDH, AST, ALT), leaves and regenerated plants of Euphorbia degeneri exhibit a modified NADP-ME-type photosynthesis. Apparently, both aspartate and malate are used for transport of CO 2 to bundle sheath cells. Callus grown on either non-shoot-forming or shoot-forming media fixes CO 2 into RPP-cycle intermediates and sucrose, as well as malate and aspartate. 14 CO 2 pulse/chase kinetics show no significant loss of label from C 4 acids throughout a one minute chase. Analysis of PEPCase revealed the presence of 2 isoenzymes in both leaf and regenerated plant tissues (K/sub m/ [PEP] = 0.080 and 0.550) but only one isoenzyme in callus (K/sub m/ = 0.100). It appears that C 4 photosynthesis does not occur in callus derived from this C 4 dicot but is regenerated concomitant with shoot regeneration, and β-carboxylation of PEP in callus, mediated by the low K/sub m/ isoenzyme of PEPCase, produces C 4 acids that are not involved in the CO 2 shuttle mechanism characteristic of C 4 photosynthesis. 161 references, 19 figures, 12 tables

  9. Drug Metabolism

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 19; Issue 3. Drug Metabolism: A Fascinating Link Between Chemistry and Biology. Nikhil Taxak Prasad V Bharatam. General Article Volume 19 Issue 3 March 2014 pp 259-282 ...

  10. Drug Metabolism

    Indian Academy of Sciences (India)

    IAS Admin

    behind metabolic reactions, importance, and consequences with several ... required for drug action. ... lism, which is catalyzed by enzymes present in the above-men- ... catalyze the transfer of one atom of oxygen to a substrate produc-.

  11. Metabolic and enzymatic changes associated with carbon mobilization, utilization and replenishment triggered in grain amaranth (Amaranthus cruentus in response to partial defoliation by mechanical injury or insect herbivory

    Directory of Open Access Journals (Sweden)

    Castrillón-Arbeláez Paula

    2012-09-01

    Full Text Available Abstract Background Amaranthus cruentus and A. hypochondriacus are crop plants grown for grain production in subtropical countries. Recently, the generation of large-scale transcriptomic data opened the possibility to study representative genes of primary metabolism to gain a better understanding of the biochemical mechanisms underlying tolerance to defoliation in these species. A multi-level approach was followed involving gene expression analysis, enzyme activity and metabolite measurements. Results Defoliation by insect herbivory (HD or mechanical damage (MD led to a rapid and transient reduction of non-structural carbohydrates (NSC in all tissues examined. This correlated with a short-term induction of foliar sucrolytic activity, differential gene expression of a vacuolar invertase and its inhibitor, and induction of a sucrose transporter gene. Leaf starch in defoliated plants correlated negatively with amylolytic activity and expression of a β-amylase-1 gene and positively with a soluble starch synthase gene. Fatty-acid accumulation in roots coincided with a high expression of a phosphoenolpyruvate/phosphate transporter gene. In all tissues there was a long-term replenishment of most metabolite pools, which allowed damaged plants to maintain unaltered growth and grain yield. Promoter analysis of ADP-glucose pyrophosphorylase and vacuolar invertase genes indicated the presence of cis-regulatory elements that supported their responsiveness to defoliation. HD and MD had differential effects on transcripts, enzyme activities and metabolites. However, the correlation between transcript abundance and enzymatic activities was very limited. A better correlation was found between enzymes, metabolite levels and growth and reproductive parameters. Conclusions It is concluded that a rapid reduction of NSC reserves in leaves, stems and roots followed by their long-term recovery underlies tolerance to defoliation in grain amaranth. This requires the

  12. METABOLIC ENGINEERING OF RAFFINOSE-FAMILY OLIGOSACCHARIDES IN THE PHLOEM REVEALS ALTERATIONS IN CARBON PARTITIONING AND ENHANCES RESISTANCE TO GREEN PEACH APHID

    Directory of Open Access Journals (Sweden)

    Te eCao

    2013-07-01

    Full Text Available Many plants employ energized loading strategies to accumulate osmotically-active solutes into the phloem of source organs to accentuate the hydrostatic pressure gradients that drive the flow of water, nutrients and signals from source to sinks. Proton-coupled symport of sugars from the apoplasm into the phloem symplasm is the best studied phloem-loading mechanism. As an alternative, numerous species use a polymer trapping mechanism to load through symplasm: sucrose enters the phloem through specialized plasmodesmata and is converted to raffinose-family oligosaccharides (RFOs which accumulate because of their larger size. In this study, metabolic engineering was used to generate RFOs at the inception of the translocation stream of Arabidopsis thaliana, which loads from the apoplasm and transports predominantly sucrose, and the fate of the sugars throughout the plant determined. Three genes, GALACTINOL SYNTHASE, RAFFINOSE SYNTHASE and STACHYOSE SYNTHASE, were expressed from promoters specific to the companion cells of minor veins. Two transgenic lines homozygous for all three genes (GRS63 and GRS47 were selected for further analysis. Three-week-old plants of both lines had RFO levels approaching 50% of total soluble sugar. RFOs were also identified in exudates from excised leaves of transgenic plants whereas levels were negligible in exudates from wild type (WT leaves. Differences in starch accumulation between WT and GRS63 and GRS47 lines were not observed. Similarly, there were no differences in vegetative growth between WT and engineered plants, but the latter flowered slightly earlier. Finally, since the sugar composition of the translocation stream appeared altered, we tested for an impact on green peach aphid (Myzus persicae Sulzer feeding. When given a choice between WT and transgenic plants, green peach aphids preferred settling on the WT plants. Furthermore, green peach aphid fecundity was lower on the transgenic plants compared to the WT

  13. Photoadaptations of photosynthesis and carbon metabolism by phytoplankton from McMurdo Sound, Antarctica. I. Species-specific and community responses to reduced irradiances

    International Nuclear Information System (INIS)

    Rivkin, R.B.; Voytek, M.A.

    1987-01-01

    Irradiance-dependent rates of photosynthesis and photosynthate labeling patterns were measured for phytoplankton in McMurdo Sound, Antarctica. Species-specific and traditional whole-water techniques were used to compare the physiological responses of algae collected in a high light environment at the ice edge and from a low light environment under the annual sea ice. There were differences among species within the same sample, for the same species isolated from high and low light environments, and when species-specific responses were compared with that of the natural assemblage. For algae collected beneath the sea ice, photosynthesis generally saturated at a lower irradiance, and the light-limited region of the P vs. I relationship had a steeper slope than for the same species collected at the ice edge. Low-light-adapted algae incorporated significantly less 14 C into proteins and more into low molecular weight compounds and lipids than the same species isolated from a high light environment. Under conditions where reduced rates of protein synthesis were coupled with high rates of carbon uptake, the measurement of photosynthesis may not accurately reflect the physiological condition of the phytoplankton

  14. Metabolic Myopathies.

    Science.gov (United States)

    Tarnopolsky, Mark A

    2016-12-01

    Metabolic myopathies are genetic disorders that impair intermediary metabolism in skeletal muscle. Impairments in glycolysis/glycogenolysis (glycogen-storage disease), fatty acid transport and oxidation (fatty acid oxidation defects), and the mitochondrial respiratory chain (mitochondrial myopathies) represent the majority of known defects. The purpose of this review is to develop a diagnostic and treatment algorithm for the metabolic myopathies. The metabolic myopathies can present in the neonatal and infant period as part of more systemic involvement with hypotonia, hypoglycemia, and encephalopathy; however, most cases present in childhood or in adulthood with exercise intolerance (often with rhabdomyolysis) and weakness. The glycogen-storage diseases present during brief bouts of high-intensity exercise, whereas fatty acid oxidation defects and mitochondrial myopathies present during a long-duration/low-intensity endurance-type activity or during fasting or another metabolically stressful event (eg, surgery, fever). The clinical examination is often normal between acute events, and evaluation involves exercise testing, blood testing (creatine kinase, acylcarnitine profile, lactate, amino acids), urine organic acids (ketones, dicarboxylic acids, 3-methylglutaconic acid), muscle biopsy (histology, ultrastructure, enzyme testing), MRI/spectroscopy, and targeted or untargeted genetic testing. Accurate and early identification of metabolic myopathies can lead to therapeutic interventions with lifestyle and nutritional modification, cofactor treatment, and rapid treatment of rhabdomyolysis.

  15. Animal metabolism

    International Nuclear Information System (INIS)

    Walburg, H.E.

    1977-01-01

    Studies on placental transport included the following: clearance of tritiated water as a baseline measurement for transport of materials across perfused placentas; transport of organic and inorganic mercury across the perfused placenta of the guinea pig in late gestation; and transport of cadmium across the perfused placenta of the guinea pig in late gestation. Studies on cadmium absorption and metabolism included the following: intestinal absorption and retention of cadmium in neonatal rats; uptake and distribution of an oral dose of cadmium in postweanling male and female, iron-deficient and normal rats; postnatal viability and growth in rat pups after oral cadmium administration during gestation; and the effect of calcium and phosphorus on the absorption and toxicity of cadmium. Studies on gastrointestinal absorption and mineral metabolism included: uptake and distribution of orally administered plutonium complex compounds in male mice; gastrointestinal absorption of 144 Ce in the newborn mouse, rat, and pig; and gastrointestinal absorption of 95 Nb by rats of different ages. Studies on iodine metabolism included the following: influence of thyroid status and thiocyanate on iodine metabolism in the bovine; effects of simulated fallout radiation on iodine metabolism in dairy cattle; and effects of feeding iodine binding agents on iodine metabolism in the calf

  16. Metabolism during ECM Detachment: Achilles Heel of Cancer Cells?

    Science.gov (United States)

    Mason, Joshua A; Hagel, Kimberly R; Hawk, Mark A; Schafer, Zachary T

    2017-07-01

    Integrin-mediated attachment to the extracellular matrix (ECM) is required to combat the induction of programmed cell death in a variety of distinct cell types. If cells fail to maintain proper ECM attachment, they become subject to elimination via an apoptotic cell death program known as anoikis. However, anoikis inhibition is not sufficient to promote the long-term survival of ECM-detached cells. Several recent studies have unveiled the profound (anoikis-independent) impact of cell metabolism on the viability of ECM-detached cells. Thus, we posit that, during metastatic dissemination (when cancer cells are exposed to periods of ECM detachment), cancer cells must alter their metabolism in a fashion that promotes survival and ultimately contributes to metastatic outgrowth. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Wukong Sharpens Its Eyes and Unveils the Nature of Dark Matter

    Science.gov (United States)

    Cong, Kun-Lin

    2016-07-01

    Dark matter does not emit light or reflect electromagnetic radiation, but its existence can be inferred from the effects of measurements such as gravity and mass. Unveiling the nature of dark matter is one of the biggest mysteries of modern science. Exploration of dark matter could give scientists a clearer understanding of the past and future of galaxies and the universe. Chinese scientists have been engaged actively in dark matter research in recent years, and made some significant achievements in theoretical studies, numerical simulations, and experimental investigation. The Dark Matter Particles Explorer Satellite (DAMPE) was launched by LM launch vehicle on 17th December 2015. It was constructed as a scientific satellite that has four major parts - a plastic scintillator array detector, a silicon array detector, a BGO calorimeter and a neutron detector - together comprising about 76,000 minor detectors. The main scientific purpose of DAMPE is to investigate dark matter particle from deep space, via high resolution observation of gamma-rays and electrons spectra, and its space distribution. It will also help scientists study the transportation and acceleration of cosmic rays in the galaxy by measuring the energy spectra of heavy ions. DAMPE was dubbed Wukong after the Monkey King character from the Chinese classic legend Journey to the West. "Wu" means becoming aware of through the senses, and "Kong" refers to the space. The figurative meaning of "Wukong" is to know and comprehend the nature of the space. DAMPE is the most sensitive and accurate detectors designed for dark matter with the highest performance among the similar explorers. It will find the evidence that can certify the existence of dark matter.

  18. Unveiled Risks in a Telecoupled Arena Dependent on Agricultural Commodity Trade

    Science.gov (United States)

    Batistella, M.; Silva, R. F. B. D.; Liu, J.; Moran, E. F.; Torres, S.; Dou, Y.

    2017-12-01

    In less than five years, a new field of interdisciplinary research has been widely developed within the coupled human-natural systems (CHANS) community. Based on well-known concepts acting over long distances, such as teleconnections for biophysical sciences and globalization for human sciences, the telecoupling framework states that long distant CHANS may be integrated through flows of capital, information, and matter, shaping environmental and socioeconomic changes within local systems. An international project including researchers from Brazil, China, United Kingdom (UK), and United States of America (USA) is using such a framework to study the flows of agricultural commodities between sending systems such as Brazil and the USA, and receiving systems such as China with soybean trade as a case in point. Many findings have already shown that these dynamics are intrinsically connected and changes in environmental conditions in one system may affect economic conditions in other systems. In the case of the double-crop practice (i.e., soybean followed by maize, two crops year round) used in some regions of Brazil, maize production is strongly connected with soybean production through the supply chain, logistics, producer regions, and farmers. Consequently, maize has been displaced to second-crop status, making it more vulnerable to rain shortfalls. The use of the telecoupling framework has also unveiled a possible threat for soybean production in the long run if it only relies on international demand and inputs. The telecoupled soybean production system has put some Brazilian farmers at economic risk, and is pushing them towards diversification and alternative production practices (e.g., non-GMO crops, biological control, in-farm seed production) to reduce their risk. This, in turn, may affect the demand-consumption relationship among traditional trading partners. With this paper, we also highlight the role of cascading effects and spillover systems of telecoupling in

  19. Engineering microbial fatty acid metabolism for biofuels and biochemicals

    DEFF Research Database (Denmark)

    Marella, Eko Roy; Holkenbrink, Carina; Siewers, Verena

    2017-01-01

    microbial catalysis. This review summarizes the recent advances in the engineering of microbial metabolism for production of fatty acid-derived products. We highlight the efforts in engineering the central carbon metabolism, redox metabolism, controlling the chain length of the products, and obtaining...

  20. [Metabolic myopathies].

    Science.gov (United States)

    Papazian, Óscar; Rivas-Chacón, Rafael

    2013-09-06

    To review the metabolic myopathies manifested only by crisis of myalgias, cramps and rigidity of the muscles with decreased voluntary contractions and normal inter crisis neurologic examination in children and adolescents. These metabolic myopathies are autosomic recessive inherited enzymatic deficiencies of the carbohydrates and lipids metabolisms. The end result is a reduction of intra muscle adenosine triphosphate, mainly through mitochondrial oxidative phosphorylation, with decrease of available energy for muscle contraction. The one secondary to carbohydrates intra muscle metabolism disorders are triggered by high intensity brief (fatty acids metabolism disorders are triggered by low intensity prolonged (> 10 min) exercises. The conditions in the first group in order of decreasing frequency are the deficiencies of myophosforilase (GSD V), muscle phosphofructokinase (GSD VII), phosphoglycerate mutase 1 (GSD X) and beta enolase (GSD XIII). The conditions in the second group in order of decreasing frequency are the deficiencies of carnitine palmitoyl transferase II and very long chain acyl CoA dehydrogenase. The differential characteristics of patients in each group and within each group will allow to make the initial presumptive clinical diagnosis in the majority and then to order only the necessary tests to achieve the final diagnosis. Treatment during the crisis includes hydration, glucose and alkalinization of urine if myoglobin in blood and urine are elevated. Prevention includes avoiding exercise which may induce the crisis and fasting. The prognosis is good with the exception of rare cases of acute renal failure due to hipermyoglobinemia because of severe rabdomyolisis.

  1. The effect of zilpaterol hydrochloride supplementation on energy metabolism and nitrogen and carbon retention of steers fed at maintenance and fasting intake levels.

    Science.gov (United States)

    Walter, L J; Cole, N A; Jennings, J S; Hutcheson, J P; Meyer, B E; Schmitz, A N; Reed, D D; Lawrence, T E

    2016-10-01

    An indirect calorimetry trial examined energy metabolism, apparent nutrient digestibility, C retention (CR), and N retention (NR) of cattle supplemented with zilpaterol hydrochloride (ZH). Beef steers ( = 20; 463 ± 14 kg) blocked ( = 5) by weight and source were individually fed and adapted to maintenance energy intake for 21 d before allotment to ZH (90 mg/steer∙d) or no β-adrenergic agonist treatment (control [CONT]) for 20 d (455 ± 14 kg at the start of treatment). Respiration chambers = 4 were used to quantify heat production (HP) during maintenance (d 12 to 16 of the ZH period) and fasting heat production (FHP; d 19 to 20 of ZH period; total 4 d of fast). Steers were harvested after a 6-d ZH withdrawal and carcasses were graded 24 h after harvest. Control cattle lost more BW ( maintenance whereas the BW loss of ZH-treated steers was greater ( maintenance ( = 0.04; 23.6 L/kgBW for ZH-treated and 22.4 L/kg BW for CONT). Digestible energy and ME did not differ ( ≥ 0.19); however, urinary energy was greater ( = 0.05; 0.091 Mcal for CONT and 0.074 Mcal for ZH-treated) in CONT cattle. Steers treated with ZH tended to have greater HP ( = 0.09; 12.44 Mcal for ZH-treated and 11.69 Mcal for CONT), but the effect was reduced on a BW basis ( = 0.12; 0.126 Mcal/kg BW0.75 for ZH-treated and 0.120 Mcal/kg BW0.75 for CONT vs. 0.120 Mcal/kg BW). No treatment difference in FHP was observed ( ≥ 0.32) although CO production (L/steer) increased with ZH treatment ( = 0.04; 1,423 L/steer for ZH-treated and 1,338 L/steer for CONT). Control cattle excreted more ( = 0.05) N in urine (39.8 g/d for CONT and 32.4 g/d for ZH-treated); therefore, NR ( = 0.07; 22.14 g/d for ZH-treated and 14.12 g/d for CONT steers) tended to be greater for ZH-fed steers. Steers treated with ZH lost more C via CO ( = 0.04; 1,036.9 g/d for ZH-treated and 974.3 g/d for CONT) although total CR did not differ ( ≥ 0.23). Empty BW, HCW, and harvest yields (g/kg empty BW) were not different ( ≥ 0

  2. Primary Metabolic Pathways and Metabolic Flux Analysis

    DEFF Research Database (Denmark)

    Villadsen, John

    2015-01-01

    his chapter introduces the metabolic flux analysis (MFA) or stoichiometry-based MFA, and describes the quantitative basis for MFA. It discusses the catabolic pathways in which free energy is produced to drive the cell-building anabolic pathways. An overview of these primary pathways provides...... the reader who is primarily trained in the engineering sciences with atleast a preliminary introduction to biochemistry and also shows how carbon is drained off the catabolic pathways to provide precursors for cell mass building and sometimes for important industrial products. The primary pathways...... to be examined in the following are: glycolysis, primarily by the EMP pathway, but other glycolytic pathways is also mentioned; fermentative pathways in which the redox generated in the glycolytic reactions are consumed; reactions in the tricarboxylic acid (TCA) cycle, which produce biomass precursors and redox...

  3. Plant metabolic modeling: achieving new insight into metabolism and metabolic engineering.

    Science.gov (United States)

    Baghalian, Kambiz; Hajirezaei, Mohammad-Reza; Schreiber, Falk

    2014-10-01

    Models are used to represent aspects of the real world for specific purposes, and mathematical models have opened up new approaches in studying the behavior and complexity of biological systems. However, modeling is often time-consuming and requires significant computational resources for data development, data analysis, and simulation. Computational modeling has been successfully applied as an aid for metabolic engineering in microorganisms. But such model-based approaches have only recently been extended to plant metabolic engineering, mainly due to greater pathway complexity in plants and their highly compartmentalized cellular structure. Recent progress in plant systems biology and bioinformatics has begun to disentangle this complexity and facilitate the creation of efficient plant metabolic models. This review highlights several aspects of plant metabolic modeling in the context of understanding, predicting and modifying complex plant metabolism. We discuss opportunities for engineering photosynthetic carbon metabolism, sucrose synthesis, and the tricarboxylic acid cycle in leaves and oil synthesis in seeds and the application of metabolic modeling to the study of plant acclimation to the environment. The aim of the review is to offer a current perspective for plant biologists without requiring specialized knowledge of bioinformatics or systems biology. © 2014 American Society of Plant Biologists. All rights reserved.

  4. Nucleotide Metabolism

    DEFF Research Database (Denmark)

    Martinussen, Jan; Willemoës, M.; Kilstrup, Mogens

    2011-01-01

    Metabolic pathways are connected through their utilization of nucleotides as supplier of energy, allosteric effectors, and their role in activation of intermediates. Therefore, any attempt to exploit a given living organism in a biotechnological process will have an impact on nucleotide metabolis...

  5. Unveiling the UHE Universe from space: the JEM-EUSO mission

    Energy Technology Data Exchange (ETDEWEB)

    Santangelo, A.; Fenu, F. [Institute of Astronomy and Astrophysics, Kepler Center for Astro and Particle Physics, Eberhard-Karls-Universitaet, Sand 1, 72076, Tuebingen (Germany); RIKEN Advanced Science Institute, 2-1 Hirosawa, Wako 351-0198 (Japan); Ebisuzaki, T.; Shinozaki, K. [RIKEN Advanced Science Institute, 2-1 Hirosawa, Wako 351-0198 (Japan)

    2011-03-15

    The Extreme Universe Space Observatory onboard the Japanese Experiment Module (JEM-EUSO) is an international mission designed to explore the origin and nature of the of ultra high-energy cosmic rays (UHECR), with energies E>5.5x10{sup 19} eV, aiming at an integrated exposure of {approx}10{sup 6} km{sup 2} sr yr at E>10{sup 20} eV. Consisting of a near-UV 2.65 m diameter telescope with a field of view of 60{sup o}, JEM-EUSO looks down from space, monitoring the dark side of the Earth, to detect the fluorescence and Cherenkov light emitted along the linear track generated by a cosmic particle traversing the atmosphere. The energy and the arrival direction of each particle will be measured while the all 4{pi} sky is monitored. The primary science goal of the mission is to identify the sources of the highest energy particles, and to measure their flux and spectrum, to unveil the mechanisms for the production, acceleration, and in situ propagation of these extreme particles. Other exploratory objectives of the mission include the study of the galactic and local extragalactic magnetic field; the detection of high-energy gamma rays and neutrinos, and tests of relativity and quantum gravity effects at extreme energies. Other aspects of fundamental physics that will be studied include the top-down models and the behavior of the neutrino cross sections at extreme energies. JEM-EUSO is also expected to conduct a systematic survey of the not yet well known energetic phenomena of the Earth's atmosphere. The mission is currently in the phase A study by JAXA and has been included in the ELIPS research pool of the European Space Agency. JEM-EUSO will be launched by an H2B rocket in the Japanese fiscal year 2016 and will be transferred to the ISS by an H2 Transfer Vehicle (HTV). It will be attached to the external experiment platform of the Japanese 'KIBO' module of the ISS. In this paper we summarize the science case, the science objectives, the technological and

  6. Secondary psychosis induced by metabolic disorders

    Directory of Open Access Journals (Sweden)

    Olivier eBonnot

    2015-05-01

    Full Text Available Metabolic disorders are not well recognized by psychiatrists as a possible source of secondary psychoses. Inborn errors of metabolism (IEMs are not frequent. Although, their prompt diagnosis may lead to suitable treatments. IEMs are well known to paediatricians, in particular for their most serious forms, having an early expression most of the time. Recent years discoveries have unveiled later expression forms, and sometimes, very discreet first physical signs. There is a growing body of evidence that supports the hypothesis that IEMs can manifest as atypical psychiatric symptoms, even in the absence of clear neurological symptoms. In the present review, we propose a detailed overview at schizophrenia-like and autism-like symptoms that can lead practitioners to bear in mind an IEM. Other psychiatric manifestations are also found, as behavioral., cognitive, learning and mood disorders. However, they are less frequent. Ensuring an accurate IEM diagnosis, in front of these psychiatric symptoms should be a priority, in order to grant suitable and valuable treatment for these pathologies.

  7. Effect of dietary fats with odd or even numbers of carbon atoms on metabolic response and muscle damage with exercise in Quarter Horse-type horses with type 1 polysaccharide storage myopathy.

    Science.gov (United States)

    Borgia, Lisa A; Valberg, Stephanie J; McCue, Molly E; Pagan, Joe D; Roe, Charles R

    2010-03-01

    To evaluate effects of fats with odd and even numbers of carbon atoms on muscle metabolism in exercising horses with polysaccharide storage myopathy (PSSM). 8 horses with PSSM (6 females and 2 males; mean +/- SD age, 6.3 +/- 3.9 years). Isocaloric diets (grain, triheptanoin, corn oil, and high-fat, low-starch [HFLS] feed) were fed for 3 weeks each; horses performed daily treadmill exercise. Grain was fed to establish an exercise target, and HFLS feed was fed as a negative control diet. Daily plasma samples were obtained. For each diet, a 15-minute exercise test was performed, and gluteus medius muscle specimens and blood samples were obtained before and after exercise. Feeding triheptanoin, compared with the corn oil diet, resulted in exercise intolerance; higher plasma creatine kinase (CK) activity and concentrations of C3:0- and C7:0-acylcarnitine and insulin; and lower concentrations of nonesterified fatty acids (NEFA) and C16:0-, C18:1-, and C18:2-acylcarnitine, without changes in concentrations of plasma glucose or resting muscle substrates and metabolites. Feeding grain induced higher CK activity and insulin concentrations and lower NEFA concentrations than did corn oil or HFLS feed. Feeding grain induced higher glucose concentrations than did triheptanoin and corn oil. In muscle, feeding grain resulted in lower glucose-6-phosphate, higher citrate, and higher postexercise lactate concentrations than did the other diets. Triheptanoin had detrimental effects, reflecting decreased availability of NEFA, increased insulin stimulation of glycogen synthesis, and potential inhibition of lipid oxidation. Long-chain fats are the best dietetic for PSSM.

  8. Metabolic regulation in the facultative methylotroph arthrobacter P1

    NARCIS (Netherlands)

    1985-01-01

    Many microorganisms are able to utilize C1 compounds, i.e. compounds which do not contain carbon-carbon bonds, as carbon- and energy sources for growth. In order to synthesize cell constituents from these C1 compounds special metabolic pathways are employed by such organisms. Although a great deal

  9. Unveiling topographical changes using LiDAR mapping capability: case study of Belaga in Sarawak, East-Malaysia

    Science.gov (United States)

    Ganendra, T. R.; Khan, N. M.; Razak, W. J.; Kouame, Y.; Mobarakeh, E. T.

    2016-06-01

    The use of Light Detection and Ranging (LiDAR) remote sensing technology to scan and map landscapes has proven to be one of the most popular techniques to accurately map topography. Thus, LiDAR technology is the ultimate method of unveiling the surface feature under dense vegetation, and, this paper intends to emphasize the diverse techniques that can be utilized to elucidate topographical changes over the study area, using multi-temporal airborne full waveform LiDAR datasets collected in 2012 and 2014. Full waveform LiDAR data offers access to an almost unlimited number of returns per shot, which enables the user to explore in detail topographical changes, such as vegetation growth measurement. The study also found out topography changes at the study area due to earthwork activities contributing to soil consolidation, soil erosion and runoff, requiring cautious monitoring. The implications of this study not only concurs with numerous investigations undertaken by prominent researchers to improve decision making, but also corroborates once again that investigations employing multi-temporal LiDAR data to unveil topography changes in vegetated terrains, produce more detailed and accurate results than most other remote sensing data.

  10. Dilemmas in the (un)veiling of the diagnosis of Alzheimer's disease: walking an ethical and professional tight rope.

    Science.gov (United States)

    Karnieli-Miller, Orit; Werner, Perla; Aharon-Peretz, Judith; Eidelman, Shmuel

    2007-08-01

    To enhance the understanding and effect of physician's difficulties, attitudes and communication styles on the disclosure of the diagnosis of AD in practice. Qualitative, phenomenological study, combining pre-encounter interviews with physicians, observations of actual encounters of diagnosis disclosure of AD, and post-encounter interviews. There were various ways or tactics to (un)veil the bad news that may be perceived as different ways of dulling the impact and avoiding full and therefore problematic statements. In the actual encounters this was accomplished by keeping encounters short, avoiding elaboration, confirmation of comprehension and explicit terminology and using fractured sentences. The present study's findings highlight the difficulties encountered in breaking the news about AD, in the way it is actually done, and the problems that may arise from this way of un/veiling the news. The main problem is that the reluctance to make a candid disclosure of the diagnosis as was demonstrated in this study may violate basic moral and legal rights and may also deprive patients and caregivers of some of the benefits of early disclosure of diagnosis. There is a need for assisting physicians to cope with their personal difficulties, problems and pitfalls in breaking the news.

  11. Metabolic Surgery

    DEFF Research Database (Denmark)

    Pareek, Manan; Schauer, Philip R; Kaplan, Lee M

    2018-01-01

    The alarming rise in the worldwide prevalence of obesity is paralleled by an increasing burden of type 2 diabetes mellitus. Metabolic surgery is the most effective means of obtaining substantial and durable weight loss in individuals with obesity. Randomized trials have recently shown...... the superiority of surgery over medical treatment alone in achieving improved glycemic control, as well as a reduction in cardiovascular risk factors. The mechanisms seem to extend beyond the magnitude of weight loss alone and include improvements in incretin profiles, insulin secretion, and insulin sensitivity....... Moreover, observational data suggest that the reduction in cardiovascular risk factors translates to better patient outcomes. This review describes commonly used metabolic surgical procedures and their current indications and summarizes the evidence related to weight loss and glycemic outcomes. It further...

  12. Metabolic Syndrome

    Directory of Open Access Journals (Sweden)

    Sevil Ikinci

    2010-10-01

    Full Text Available Metabolic Syndrome is a combination of risk factors including common etiopathogenesis. These risk factors play different roles in occurence of atherosclerotic diseases, type 2 diabetes, and cancers. Although a compromise can not be achieved on differential diagnosis for MS, the existence of any three criterias enable to diagnose MS. These are abdominal obesity, dislipidemia (hypertrigliceridemia, hypercholesterolemia, and reduced high density lipoprotein hypertension, and elevated fasting blood glucose. According to the results of Metabolic Syndrome Research (METSAR, the overall prevalence of MS in Turkey is 34%; in females 40%, and in males it is 28%. As a result of “Western” diet, and increased frequency of obesity, MS is observed in children and in adolescents both in the world and in Turkey. Resulting in chronic diseases, it is thought that the syndrome can be prevented by healthy lifestyle behaviours. [TAF Prev Med Bull 2010; 9(5.000: 535-540

  13. Cellular metabolism

    International Nuclear Information System (INIS)

    Hildebrand, C.E.; Walters, R.A.

    1977-01-01

    Progress is reported on the following research projects: chromatin structure; the use of circular synthetic polydeoxynucleotides as substrates for the study of DNA repair enzymes; human cellular kinetic response following exposure to DNA-interactive compounds; histone phosphorylation and chromatin structure in cell proliferation; photoaddition products induced in chromatin by uv light; pollutants and genetic information transfer; altered RNA metabolism as a function of cadmium accumulation and intracellular distribution in cultured cells; and thymidylate chromophore destruction by water free radicals

  14. The Relationship between Growth-Inequality-Poverty Triangle and Environmental Degradation: Unveiling the Reality

    Directory of Open Access Journals (Sweden)

    Syeda Anam Hassan

    2015-06-01

    Full Text Available It is important to recognize that increase in well-being is no longer dependent on further economic growth, but on economic and social well-being, which means that the decline in carbon dioxide emission without reducing real wellbeing and growth. The aim of this study is to investigate the main driving forces affecting short and long-run carbon emissions pattern due to changes in growth, inequality and poverty triangle in Pakistan over the period 1980 – 2011 by using multivariate cointegration approach. This study uses five different models i.e., each model have an important policy implication in the context of Pakistan. The results indicate that, on the short run, there is a significant negative relationship between economic growth & carbon emissions and economic growth & poverty while there is a positive relationship between i economic growth & income inequality; and ii poverty & income inequality. On the long-run, there is a significant positive relationship between GDP & income inequality, carbon dioxide emissions & income inequality, and poverty & income inequality in Pakistan. On the other side, there is a negative relationship between carbon emissions & economic growth, carbon emissions & income inequality, and economic growth & income inequality. The results of environmental Kuznets curve (EKC hypothesis show an inverted U-shaped trajectory in relation to economic growth in Pakistan. This study contributes to the debate on the existence and policy relevance of the EKC for Pakistan. The conclusion ensures the sustainability of an urgent need to look beyond the EKC by adopting courageous policy measures of environmental preservation in Pakistan irrespective of the country's level of income. For reduction of CO2 emission, environmental progressive management policies, economic transport system regulations, and low emit fuel consumption by industries are the need of the world.

  15. Gr and hp-1 tomato mutants unveil unprecedented interactions between arbuscular mycorrhizal symbiosis and fruit ripening

    Science.gov (United States)

    The roots of plants interact with soil mycorrhizal fungi to facilitate soil nutrient acquisition by the plant and carbon transfer to the fungus. Here we use tomato fruit ripening mutations to demonstrate that this root interaction communicates with and supports genetic mechanisms associated with th...

  16. Central Carbon Metabolic Pathways in Streptomyces

    NARCIS (Netherlands)

    van Keulen, Geertje; Siebring, Jeroen; Dijkhuizen, Lubbert; Dyson, Paul

    Streptomyces and other actinomycetes are fascinating soil bacteria of major economic importance. They produce 70% of antibiotics known to man and numerous other pharmaceuticals for treatment of, e.g. cancer, a range of infections, high cholesterol, or have immunosuppressive activity. It is not

  17. Glutamine synthetase in Medicago truncatula, unveiling new secrets of a very old enzyme

    Directory of Open Access Journals (Sweden)

    Ana Rita Seabra

    2015-07-01

    Full Text Available Glutamine Synthetase (GS catalyses the first step at which nitrogen is brought into cellular metabolism and is also involved in the reassimilation of ammonium released by a number of metabolic pathways. Due to its unique position in plant nitrogen metabolism, GS plays essential roles in all aspects of plant development, from germination to senescence, and is a key component of nitrogen use efficiency (NUE and plant yield. Understanding the mechanisms regulating GS activity is therefore of utmost importance and a great effort has been dedicated to understand how GS is regulated in different plant species. The present review summarizes exciting recent developments concerning the structure and regulation of glutamine synthetase isoenzymes, using the model legume Medicago truncatula. These include the understanding of the structural determinants of both the cytosolic and plastid located isoenzymes, the existence of a seed-specific GS gene unique to M. truncatula and closely related species and the discovery that GS isoenzymes are regulated by nitric oxide at the post-translational level. The data is discussed and integrated with the potential roles of the distinct GS isoenzymes within the whole plant context.

  18. Effect of metabolic alkalosis on respiratory function in patients with chronic obstructive lung disease.

    Science.gov (United States)

    Bear, R.; Goldstein, M.; Phillipson, E.; Ho, M.; Hammeke, M.; Feldman, R.; Handelsman, S.; Halperin, M.

    1977-01-01

    Eleven instances of a mixed acid-base disorder consisting of chronic respiratory acidosis and metabolic alkalosis were recognized in eight patients with chronic obstructive lung disease and carbon dioxide retention. Correction of the metabolic alkalosis led to substantial improvement in blood gas values and clinical symptoms. Patients with mixed chronic respiratory acidosis and metabolic alkalosis constitute a common subgroup of patients with chronic obstructive lung disease and carbon dioxide retention; these patients benefit from correction of the metabolic alkalosis. PMID:21028

  19. Carbon isotopes in mollusk shell carbonates

    Science.gov (United States)

    McConnaughey, Ted A.; Gillikin, David Paul

    2008-10-01

    Mollusk shells contain many isotopic clues about calcification physiology and environmental conditions at the time of shell formation. In this review, we use both published and unpublished data to discuss carbon isotopes in both bivalve and gastropod shell carbonates. Land snails construct their shells mainly from respired CO2, and shell δ13C reflects the local mix of C3 and C4 plants consumed. Shell δ13C is typically >10‰ heavier than diet, probably because respiratory gas exchange discards CO2, and retains the isotopically heavier HCO3 -. Respired CO2 contributes less to the shells of aquatic mollusks, because CO2/O2 ratios are usually higher in water than in air, leading to more replacement of respired CO2 by environmental CO2. Fluid exchange with the environment also brings additional dissolved inorganic carbon (DIC) into the calcification site. Shell δ13C is typically a few ‰ lower than ambient DIC, and often decreases with age. Shell δ13C retains clues about processes such as ecosystem metabolism and estuarine mixing. Ca2+ ATPase-based models of calcification physiology developed for corals and algae likely apply to mollusks, too, but lower pH and carbonic anhydrase at the calcification site probably suppress kinetic isotope effects. Carbon isotopes in biogenic carbonates are clearly complex, but cautious interpretation can provide a wealth of information, especially after vital effects are better understood.

  20. IEEE Milestone at CERN - W Cleon Anderson (right), president of the Institute of Electrical and Electronics Engineers, unveils the Milestone plaque at CERN, together with Georges Charpak

    CERN Multimedia

    Maximilien Brice

    2005-01-01

    At a ceremony on 26 September at CERN, W Cleon Anderson, president of the Institute of Electrical and Electronics Engineers (IEEE), formally dedicated a "Milestone" plaque in recognition of the invention of electronic particle detectors at CERN. The plaque was unveiled by Anderson and Georges Charpak, the Nobel-prize winning inventor of wire-chamber technology at CERN.

  1. Effect of plant density on soybean carbon and nitrogen metabolism, yield and quality%密度对大豆群体碳氮代谢相关指标及产量、品质的影响

    Institute of Scientific and Technical Information of China (English)

    张晓艳; 郑殿峰; 冯乃杰; 李建英; 杜吉到

    2011-01-01

    Effects of plant density on carbon and nitrogen metabolism, yield and quality of soybean cultivar Kennong 4 were investigated in field. The results showed that nitrogen, soluble protein, starch and cane sugar accumulation increased gradually with the increase of plant density, and there was significant difference among different density of soybean populations; With the increase of density, the proten content in soybean seed increased but fat content decreased;Through analyzing correlation at each stage, we known that there was a negative correlation among nitrogen, soluble protein, starch and cane sugar accumulation and proten content, and a positive correlation with fat content; The pod number, seed number and seed weight went higher when the density got smaller, and the yield of 3.6 × lO5-plants-per-hm2 reached to the highest.%以垦农4号大豆为试验材料,在大田条件下,研究了密度对大豆群体碳氮代谢相关指标及产量品质的影响.结果表明,群体单株叶片氮素、可溶性蛋白、淀粉及蔗糖积累量均随着密度的增加而下降,低密度与高密度群体间差距显著;随着种植密度的增加,大豆子粒中蛋白质的含量有所上升,脂肪的含量有所下降;各生育时期氮素、可溶性蛋白、淀粉和蔗糖积累量与子粒蛋白质含量呈负相关,与脂肪含量呈正相关;随着种植密度的增加,群体内单株的荚数、粒数、粒重逐渐减少.在密度36万株/hm时,群体产量最高.

  2. Unveiling the pan-genome of the SXT/R391 family of ICEs: molecular characterisation of new variable regions of SXT/R391-like ICEs detected in Pseudoalteromonas sp. and Vibrio scophthalmi.

    Science.gov (United States)

    Rodríguez-Blanco, Arturo; Lemos, Manuel L; Osorio, Carlos R

    2016-08-01

    Integrating conjugative elements (ICEs) of the SXT/R391 family have been identified in fish-isolated bacterial strains collected from marine aquaculture environments of the northwestern Iberian Peninsula. Here we analysed the variable regions of two ICEs, one preliminarily characterised in a previous study (ICEVscSpa3) and one newly identified (ICEPspSpa1). Bacterial strains harboring these ICEs were phylogenetically assigned to Vibrio scophthalmi and Pseudoalteromonas sp., thus constituting the first evidence of SXT/R391-like ICEs in the genus Pseudoalteromonas to date. Variable DNA regions, which confer element-specific properties to ICEs of this family, were characterised. Interestingly, the two ICEs contained 29 genes not found in variable DNA insertions of previously described ICEs. Most notably, variable gene content for ICEVscSpa3 showed similarity to genes potentially involved in housekeeping functions of replication, nucleotide metabolism and transcription. For these genes, closest homologues were found clustered in the genome of Pseudomonas psychrotolerans L19, suggesting a transfer as a block to ICEVscSpa3. Genes encoding antibiotic resistance, restriction modification systems and toxin/antitoxin systems were absent from hotspots of ICEVscSpa3. In contrast, the variable gene content of ICEPspSpa1 included genes involved in restriction/modification functions in two different hotspots and genes related to ICE maintenance. The present study unveils a relatively large number of novel genes in SXT/R391-ICEs, and demonstrates the major role of ICE elements as contributors to horizontal gene transfer.

  3. Isotopic labeling affects 1,25-dihydroxyvitamin D metabolism

    International Nuclear Information System (INIS)

    Halloran, B.P.; Bikle, D.D.; Castro, M.E.; Gee, E.

    1989-01-01

    Isotope substitution can change the biochemical properties of vitamin D. To determine the effect of substituting 3H for 1H on the metabolism of 1,25(OH)2D3, we measured the metabolic clearance rate and renal metabolism of unlabeled and 3H-labeled 1,25(OH)2D3. Substitution of 3H for 1H on carbons 26 and 27 [1,25(OH)2[26,27(n)-3H]D3] or on carbons 23 and 24 [1,25(OH)2[23,24(n)-3H]D3] reduced the in vivo metabolic clearance rate of 1,25(OH)2D3 by 36% and 37%, respectively, and reduced the in vitro renal catabolism of 1,25(OH)2D3 by 11% and 54%, respectively. Substitutions of 3H for 1H on carbons 23 and 24 as opposed to carbons 26 and 27 reduced conversion of [3H]1,25(OH)2D3 to [3H]1,24,25(OH)2D3 by 25% and to putative 24-oxo-1,23,25-dihydroxyvitamin D3 by 1600%. These results indicate that substitution of 3H for 1H on carbons 26 and 27 or on carbons 23 and 24 can reduce the metabolic clearance rate and in vitro metabolism of 1,25(OH)2D3 and quantitatively alter the pattern of metabolic products produced

  4. Sirtuins: Novel targets for metabolic disease in drug development

    International Nuclear Information System (INIS)

    Jiang Weijian

    2008-01-01

    Calorie restriction extends lifespan and produces a metabolic profile desirable for treating diseases such as type 2 diabetes. SIRT1, an NAD + -dependent deacetylase, is a principal modulator of pathways downstream of calorie restriction that produces beneficial effects on glucose homeostasis and insulin sensitivity. Activation of SIRT1 leads to enhanced activity of multiple proteins, including peroxisome proliferator-activated receptor coactivator-1α (PGC-1α) and FOXO which helps to mediate some of the in vitro and in vivo effects of sirtuins. Resveratrol, a polyphenolic SIRT1 activator, mimics the effects of calorie restriction in lower organisms and in mice fed a high-fat diet ameliorates insulin resistance. In this review, we summarize recent research advances in unveiling the molecular mechanisms that underpin sirtuin as therapeutic candidates and discuss the possibility of using resveratrol as potential drug for treatment of diabetes

  5. Enhancer Analysis Unveils Genetic Interactions between TLX and SOX2 in Neural Stem Cells and In Vivo Reprogramming.

    Science.gov (United States)

    Islam, Mohammed M; Smith, Derek K; Niu, Wenze; Fang, Sanhua; Iqbal, Nida; Sun, Guoqiang; Shi, Yanhong; Zhang, Chun-Li

    2015-11-10

    The orphan nuclear receptor TLX is a master regulator of postnatal neural stem cell (NSC) self-renewal and neurogenesis; however, it remains unclear how TLX expression is precisely regulated in these tissue-specific stem cells. Here, we show that a highly conserved cis-element within the Tlx locus functions to drive gene expression in NSCs. We demonstrate that the transcription factors SOX2 and MYT1 specifically interact with this genomic element to directly regulate Tlx enhancer activity in vivo. Knockdown experiments further reveal that SOX2 dominantly controls endogenous expression of TLX, whereas MYT1 only plays a modulatory role. Importantly, TLX is essential for SOX2-mediated in vivo reprogramming of astrocytes and itself is also sufficient to induce neurogenesis in the adult striatum. Together, these findings unveil functional genetic interactions among transcription factors that are critical to NSCs and in vivo cell reprogramming.

  6. Enhancer Analysis Unveils Genetic Interactions between TLX and SOX2 in Neural Stem Cells and In Vivo Reprogramming

    Science.gov (United States)

    Islam, Mohammed M.; Smith, Derek K.; Niu, Wenze; Fang, Sanhua; Iqbal, Nida; Sun, Guoqiang; Shi, Yanhong; Zhang, Chun-Li

    2015-01-01

    Summary The orphan nuclear receptor TLX is a master regulator of postnatal neural stem cell (NSC) self-renewal and neurogenesis; however, it remains unclear how TLX expression is precisely regulated in these tissue-specific stem cells. Here, we show that a highly conserved cis-element within the Tlx locus functions to drive gene expression in NSCs. We demonstrate that the transcription factors SOX2 and MYT1 specifically interact with this genomic element to directly regulate Tlx enhancer activity in vivo. Knockdown experiments further reveal that SOX2 dominantly controls endogenous expression of TLX, whereas MYT1 only plays a modulatory role. Importantly, TLX is essential for SOX2-mediated in vivo reprogramming of astrocytes and itself is also sufficient to induce neurogenesis in the adult striatum. Together, these findings unveil functional genetic interactions among transcription factors that are critical to NSCs and in vivo cell reprogramming. PMID:26607952

  7. Enhancer Analysis Unveils Genetic Interactions between TLX and SOX2 in Neural Stem Cells and In Vivo Reprogramming

    Directory of Open Access Journals (Sweden)

    Mohammed M. Islam

    2015-11-01

    Full Text Available The orphan nuclear receptor TLX is a master regulator of postnatal neural stem cell (NSC self-renewal and neurogenesis; however, it remains unclear how TLX expression is precisely regulated in these tissue-specific stem cells. Here, we show that a highly conserved cis-element within the Tlx locus functions to drive gene expression in NSCs. We demonstrate that the transcription factors SOX2 and MYT1 specifically interact with this genomic element to directly regulate Tlx enhancer activity in vivo. Knockdown experiments further reveal that SOX2 dominantly controls endogenous expression of TLX, whereas MYT1 only plays a modulatory role. Importantly, TLX is essential for SOX2-mediated in vivo reprogramming of astrocytes and itself is also sufficient to induce neurogenesis in the adult striatum. Together, these findings unveil functional genetic interactions among transcription factors that are critical to NSCs and in vivo cell reprogramming.

  8. Unveiling the strangeness secrets: low-energy kaon-nucleon/nuclei interactions studies at DAΦNE

    Directory of Open Access Journals (Sweden)

    Curceanu C.

    2014-03-01

    Full Text Available The DAΦNE electron-positron collider at the Laboratori Nazionali di Frascati of INFN, Italy has made available a unique quality low-energy negatively charged kaons “beam”, which is used to unveil the secrets of the kaon-nucleon/nuclei interactions at low energies by the SIDDHARTA-2 and AMADEUS experiments. SIDDHARTA has already performed unprecedented precision measurements of kaonic atoms, and is being presently upgraded, as SIDDHARTA-2, to approach new frontiers. The AMADEUS experiment plans to perform in the coming years precision measurements on kaon-nuclei interactions at low-energies, to study the possible formation of kaonic nuclei, of the Λ(1405 and of many other processes involving strangeness.

  9. Social Networking Sites in the Classroom: Unveiling New Roles for Teachers and New Approaches to Online Course Design

    Directory of Open Access Journals (Sweden)

    Jorge Eduardo Pineda Hoyos

    2014-12-01

    Full Text Available Web 2.0 tools in general and social networking sites in particular are very popular today in everyday life. However, their use in education has not been explored. This paper reports the findings of the implementation of a web 2.0 tool namely a social networking site as a web support for a face-to-face course. The findings show that the implementation of a web-based environment in a face-to-face course can be viewed from 5 different managerial areas: (1 logistics management, (2 information/knowledge management, (3 communication management, (4 class work extension management and (5 web-based environment easiness of accessibility. The conclusions of the study show that the implementation of the web-based environment unveils new roles for teachers and new approaches to design online or blended courses.

  10. Variability of building environmental assessment tools on evaluating carbon emissions

    Energy Technology Data Exchange (ETDEWEB)

    Ng, S. Thomas, E-mail: tstng@hkucc.hku.hk; Chen Yuan, E-mail: chenyuan4@gmail.com; Wong, James M.W., E-mail: jmwwong@hku.hk

    2013-01-15

    With an increasing importance of sustainability in construction, more and more clients and designers employ building environmental assessment (BEA) tools to evaluate the environmental friendliness of their building facilities, and one important aspect of evaluation in the BEA models is the assessment of carbon emissions. However, in the absence of any agreed framework for carbon auditing and benchmarking, the results generated by the BEA tools might vary significantly which could lead to confusion or misinterpretation on the carbon performance of a building. This study thus aims to unveil the properties of and the standard imposed by the current BEA models on evaluating the life cycle carbon emissions. The analyses cover the (i) weighting of energy efficiency and emission levels among various environmental performance indicators; (ii) building life cycle stages in which carbon is taken into consideration; (iii) objectiveness of assessment; (iv) baseline set for carbon assessment; (v) mechanism for benchmarking the emission level; and (v) limitations of the carbon assessment approaches. Results indicate that the current BEA schemes focus primarily on operational carbon instead of the emissions generated throughout the entire building life cycle. Besides, the baseline and benchmark for carbon evaluation vary significantly among the BEA tools based on the analytical results of a hypothetical building. The findings point to the needs for a more transparent framework for carbon auditing and benchmarking in BEA modeling. - Highlights: Black-Right-Pointing-Pointer Carbon emission evaluation in building environmental assessment schemes are studied. Black-Right-Pointing-Pointer Simulative carbon emission is modeled for building environmental assessment schemes. Black-Right-Pointing-Pointer Carbon assessments focus primarily on operational stage instead of entire lifecycle. Black-Right-Pointing-Pointer Baseline and benchmark of carbon assessment vary greatly among BEA

  11. Variability of building environmental assessment tools on evaluating carbon emissions

    International Nuclear Information System (INIS)

    Ng, S. Thomas; Chen Yuan; Wong, James M.W.

    2013-01-01

    With an increasing importance of sustainability in construction, more and more clients and designers employ building environmental assessment (BEA) tools to evaluate the environmental friendliness of their building facilities, and one important aspect of evaluation in the BEA models is the assessment of carbon emissions. However, in the absence of any agreed framework for carbon auditing and benchmarking, the results generated by the BEA tools might vary significantly which could lead to confusion or misinterpretation on the carbon performance of a building. This study thus aims to unveil the properties of and the standard imposed by the current BEA models on evaluating the life cycle carbon emissions. The analyses cover the (i) weighting of energy efficiency and emission levels among various environmental performance indicators; (ii) building life cycle stages in which carbon is taken into consideration; (iii) objectiveness of assessment; (iv) baseline set for carbon assessment; (v) mechanism for benchmarking the emission level; and (v) limitations of the carbon assessment approaches. Results indicate that the current BEA schemes focus primarily on operational carbon instead of the emissions generated throughout the entire building life cycle. Besides, the baseline and benchmark for carbon evaluation vary significantly among the BEA tools based on the analytical results of a hypothetical building. The findings point to the needs for a more transparent framework for carbon auditing and benchmarking in BEA modeling. - Highlights: ► Carbon emission evaluation in building environmental assessment schemes are studied. ► Simulative carbon emission is modeled for building environmental assessment schemes. ► Carbon assessments focus primarily on operational stage instead of entire lifecycle. ► Baseline and benchmark of carbon assessment vary greatly among BEA schemes. ► A more transparent and comprehensive framework for carbon assessment is required.

  12. Database of normal human cerebral blood flow, cerebral blood volume, cerebral oxygen extraction fraction and cerebral metabolic rate of oxygen measured by positron emission tomography with {sup 15}O-labelled carbon dioxide or water, carbon monoxide and oxygen: a multicentre study in Japan

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Hiroshi [Department of Radiology and Nuclear Medicine, Akita Research Institute of Brain and Blood Vessels, Akita (Japan); Department of Nuclear Medicine and Radiology, Division of Brain Sciences, Institute of Development, Aging and Cancer, Tohoku University, 4-1 Seiryo-Machi, 980-8575, Aoba-Ku, Sendai (Japan); Kanno, Iwao [Department of Radiology and Nuclear Medicine, Akita Research Institute of Brain and Blood Vessels, Akita (Japan); Kato, Chietsugu [Department of Nuclear Medicine, Hokkaido University School of Medicine, Sapporo (Japan); Sasaki, Toshiaki [Cyclotoron Research Center, Iwate Medical University, Morioka (Japan); Ishii, Kenji [Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, Tokyo (Japan); Ouchi, Yasuomi [Positron Medical Center, Hamamatsu Medical Center, Hamakita (Japan); Iida, Akihiko [Nagoya City Rehabilitation Center, Nagoya (Japan); Okazawa, Hidehiko [PET Unit, Research Institute, Shiga Medical Center, Moriyama (Japan); Hayashida, Kohei [Department of Radiology, National Cardiovascular Center, Suita, Osaka (Japan); Tsuyuguchi, Naohiro [Department of Neurosurgery, Osaka City University Medical School, Osaka (Japan); Ishii, Kazunari [Division of Imaging Research, Hyogo Institute for Aging Brain and Cognitive Disorders, Himeji, Hyogo (Japan); Kuwabara, Yasuo [Department of Radiology, Faculty of Medicine, Kyushu University, Fukuoka (Japan); Senda, Michio [Department of Image-based Medicine, Institute of Biomedical Research and Innovation, Kobe (Japan)

    2004-05-01

    Measurement of cerebral blood flow (CBF), cerebral blood volume (CBV), cerebral oxygen extraction fraction (OEF) and cerebral metabolic rate of oxygen (CMRO{sub 2}) by positron emission tomography (PET) with oxygen-15 labelled carbon dioxide (C{sup 15}O{sub 2}) or {sup 15}O-labelled water (H{sub 2}{sup 15}O), {sup 15}O-labelled carbon monoxide (C{sup 15}O) and {sup 15}O-labelled oxygen ({sup 15}O{sub 2}) is useful for diagnosis and treatment planning in cases of cerebrovascular disease. The measured values theoretically depend on various factors, which may differ between PET centres. This study explored the applicability of a database of {sup 15}O-PET by examining between-centre and within-centre variation in values. Eleven PET centres participated in this multicentre study; seven used the steady-state inhalation method, one used build-up inhalation and three used bolus administration of C{sup 15}O{sub 2} (or H{sub 2}{sup 15}O) and {sup 15}O{sub 2}. All used C{sup 15}O for measurement of CBV. Subjects comprised 70 healthy volunteers (43 men and 27 women; mean age 51.8{+-}15.1 years). Overall mean{+-}SD values for cerebral cortical regions were: CBF=44.4{+-}6.5 ml 100 ml{sup -1} min{sup -1}; CBV=3.8{+-}0.7 ml 100 ml{sup -1}; OEF=0.44{+-}0.06; CMRO{sub 2}=3.3{+-}0.5 ml 100 ml{sup -1} min{sup -1}. Significant between-centre variation was observed in CBV, OEF and CMRO{sub 2} by one-way analysis of variance. However, the overall inter-individual variation in CBF, CBV, OEF and CMRO{sub 2} was acceptably small. Building a database of normal cerebral haemodynamics obtained by the{sup 15}O-PET methods may be practicable. (orig.)

  13. Global network reorganization during dynamic adaptations of Bacillus subtilis metabolism

    DEFF Research Database (Denmark)

    Buescher, Joerg Martin; Liebermeister, Wolfram; Jules, Matthieu

    2012-01-01

    Adaptation of cells to environmental changes requires dynamic interactions between metabolic and regulatory networks, but studies typically address only one or a few layers of regulation. For nutritional shifts between two preferred carbon sources of Bacillus subtilis, we combined statistical...

  14. Unveiling the role and life strategies of viruses from the surface to the dark ocean

    KAUST Repository

    Lara, Elena; Vaqué , Dolors; Sà , Elisabet Laia; Boras, Julia A.; Gomes, Ana; Borrull, Encarna; Dí ez-Vives, Cristina; Teira, Eva; Pernice, Massimo C.; Garcia, Francisca C.; Forn, Irene; Castillo, Yaiza M.; Peiró , Aida; Salazar, Guillem; Moran, Xose Anxelu G.; Massana, Ramon; Catalá , Teresa S.; Luna, Gian Marco; Agusti, Susana; Estrada, Marta; Gasol, Josep M M; Duarte, Carlos M.

    2017-01-01

    Viruses are a key component of marine ecosystems, but the assessment of their global role in regulating microbial communities and the flux of carbon is precluded by a paucity of data, particularly in the deep ocean. We assessed patterns in viral abundance and production and the role of viral lysis as a driver of prokaryote mortality, from surface to bathypelagic layers, across the tropical and subtropical oceans. Viral abundance showed significant differences between oceans in the epipelagic and mesopelagic, but not in the bathypelagic, and decreased with depth, with an average power-law scaling exponent of −1.03 km−1 from an average of 7.76 × 106 viruses ml−1 in the epipelagic to 0.62 × 106 viruses ml−1 in the bathypelagic layer with an average integrated (0 to 4000 m) viral stock of about 0.004 to 0.044 g C m−2, half of which is found below 775 m. Lysogenic viral production was higher than lytic viral production in surface waters, whereas the opposite was found in the bathypelagic, where prokaryotic mortality due to viruses was estimated to be 60 times higher than grazing. Free viruses had turnover times of 0.1 days in the bathypelagic, revealing that viruses in the bathypelagic are highly dynamic. On the basis of the rates of lysed prokaryotic cells, we estimated that viruses release 145 Gt C year−1 in the global tropical and subtropical oceans. The active viral processes reported here demonstrate the importance of viruses in the production of dissolved organic carbon in the dark ocean, a major pathway in carbon cycling.

  15. Unveiling the role and life strategies of viruses from the surface to the dark ocean

    KAUST Repository

    Lara, Elena

    2017-09-07

    Viruses are a key component of marine ecosystems, but the assessment of their global role in regulating microbial communities and the flux of carbon is precluded by a paucity of data, particularly in the deep ocean. We assessed patterns in viral abundance and production and the role of viral lysis as a driver of prokaryote mortality, from surface to bathypelagic layers, across the tropical and subtropical oceans. Viral abundance showed significant differences between oceans in the epipelagic and mesopelagic, but not in the bathypelagic, and decreased with depth, with an average power-law scaling exponent of −1.03 km−1 from an average of 7.76 × 106 viruses ml−1 in the epipelagic to 0.62 × 106 viruses ml−1 in the bathypelagic layer with an average integrated (0 to 4000 m) viral stock of about 0.004 to 0.044 g C m−2, half of which is found below 775 m. Lysogenic viral production was higher than lytic viral production in surface waters, whereas the opposite was found in the bathypelagic, where prokaryotic mortality due to viruses was estimated to be 60 times higher than grazing. Free viruses had turnover times of 0.1 days in the bathypelagic, revealing that viruses in the bathypelagic are highly dynamic. On the basis of the rates of lysed prokaryotic cells, we estimated that viruses release 145 Gt C year−1 in the global tropical and subtropical oceans. The active viral processes reported here demonstrate the importance of viruses in the production of dissolved organic carbon in the dark ocean, a major pathway in carbon cycling.

  16. Comparative fecal metagenomics unveils unique functional capacity of the swine gut

    Directory of Open Access Journals (Sweden)

    Martinson John

    2011-05-01

    Full Text Available Abstract Background Uncovering the taxonomic composition and functional capacity within the swine gut microbial consortia is of great importance to animal physiology and health as well as to food and water safety due to the presence of human pathogens in pig feces. Nonetheless, limited information on the functional diversity of the swine gut microbiome is available. Results Analysis of 637, 722 pyrosequencing reads (130 megabases generated from Yorkshire pig fecal DNA extracts was performed to help better understand the microbial diversity and largely unknown functional capacity of the swine gut microbiome. Swine fecal metagenomic sequences were annotated using both MG-RAST and JGI IMG/M-ER pipelines. Taxonomic analysis of metagenomic reads indicated that swine fecal microbiomes were dominated by Firmicutes and Bacteroidetes phyla. At a finer phylogenetic resolution, Prevotella spp. dominated the swine fecal metagenome, while some genes associated with Treponema and Anareovibrio species were found to be exclusively within the pig fecal metagenomic sequences analyzed. Functional analysis revealed that carbohydrate metabolism was the most abundant SEED subsystem, representing 13% of the swine metagenome. Genes associated with stress, virulence, cell wall and cell capsule were also abundant. Virulence factors associated with antibiotic resistance genes with highest sequence homology to genes in Bacteroidetes, Clostridia, and Methanosarcina were numerous within the gene families unique to the swine fecal metagenomes. Other abundant proteins unique to the distal swine gut shared high sequence homology to putative carbohydrate membrane transporters. Conclusions The results from this metagenomic survey demonstrated the presence of genes associated with resistance to antibiotics and carbohydrate metabolism suggesting that the swine gut microbiome may be shaped by husbandry practices.

  17. Microbially mediated mineral carbonation

    Science.gov (United States)

    Power, I. M.; Wilson, S. A.; Dipple, G. M.; Southam, G.

    2010-12-01

    Mineral carbonation involves silicate dissolution and carbonate precipitation, which are both natural processes that microorganisms are able to mediate in near surface environments (Ferris et al., 1994; Eq. 1). (Ca,Mg)SiO3 + 2H2CO3 + H2O → (Ca,Mg)CO3 + H2O + H4SiO4 + O2 (1) Cyanobacteria are photoautotrophs with cell surface characteristics and metabolic processes involving inorganic carbon that can induce carbonate precipitation. This occurs partly by concentrating cations within their net-negative cell envelope and through the alkalinization of their microenvironment (Thompson & Ferris, 1990). Regions with mafic and ultramafic bedrock, such as near Atlin, British Columbia, Canada, represent the best potential sources of feedstocks for mineral carbonation. The hydromagnesite playas near Atlin are a natural biogeochemical model for the carbonation of magnesium silicate minerals (Power et al., 2009). Field-based studies at Atlin and corroborating laboratory experiments demonstrate the ability of a microbial consortium dominated by filamentous cyanobacteria to induce the precipitation of carbonate minerals. Phototrophic microbes, such as cyanobacteria, have been proposed as a means for producing biodiesel and other value added products because of their efficiency as solar collectors and low requirement for valuable, cultivable land in comparison to crops (Dismukes et al., 2008). Carbonate precipitation and biomass production could be facilitated using specifically designed ponds to collect waters rich in dissolved cations (e.g., Mg2+ and Ca2+), which would allow for evapoconcentration and provide an appropriate environment for growth of cyanobacteria. Microbially mediated carbonate precipitation does not require large quantities of energy or chemicals needed for industrial systems that have been proposed for rapid carbon capture and storage via mineral carbonation (e.g., Lackner et al., 1995). Therefore, this biogeochemical approach may represent a readily

  18. Nort-South gradients in plasma concentrations of B-vitamins and other components of one-carbon metabolism in Western Europe: results from the European Prospective Investigation into Cancer and Nutrition (EPIC) Study

    NARCIS (Netherlands)

    Eussen, S.J.P.M.; Nilsen, R.M.; Midttun, O.; Hustad, S.; IJssenagger, N.; Meyer, K.; Fredriksen, A.; Ulvik, A.; Ueland, P.M.; Brennan, P.; Johansson, M.; Bueno-de-Mesquita, B.; Vineis, P.; Chuang, S.C.; Boutron-Ruault, M.C.; Dossus, L.; Perquier, F.; Overvad, K.; Teucher, B.; Grote, V.A.; Trichopoulou, A.; Adarakis, G.; Plada, M.; Sieri, S.; Tumino, R.; Santucci de Magistris, M.; Ros, M.M.; Peeters, P.H.M.; Redondo, M.L.; Zamora-Ros, R.; Chirlaque, M.D.; Ardanaz, E.; Sonestedt, E.; Ericson, U.; Schneede, J.; Guelpen, B.; Wark, P.A.; Gallo, V.; Norat, T.; Riboli, E.; Vollset, S.E.

    2013-01-01

    Different lifestyle patterns across Europe may influence plasma concentrations of B-vitamins and one-carbon metabolites and their relation to chronic disease. Comparison of published data on one-carbon metabolites in Western European regions is difficult due to differences in sampling procedures and

  19. North-south gradients in plasma concentrations of B-vitamins and other components of one-carbon metabolism in Western Europe: results from the European Prospective Investigation into Cancer and Nutrition (EPIC) Study

    NARCIS (Netherlands)

    Eussen, S.J.; Nilsen, R.M.; Midttun, O.; Hustad, S.; N, I.J.; Meyer, K.; Fredriksen, A.; Ulvik, A.; Ueland, P.M.; Brennan, P.; Johansson, M.; Bueno-de-Mesquita, B.; Vineis, P.; Chuang, S.C.; Boutron-Ruault, M.C.; Dossus, L.; Perquier, F.; Overvad, K.; Teucher, B.; Grote, V.A.; Trichopoulou, A.; Adarakis, G.; Plada, M.; Sieri, S.; Tumino, R.; Magistris, M.S. de; Ros, M.M.; Peeters, P.H.M.; Redondo, M.L.; Zamora-Ros, R.; Chirlaque, M.D.; Ardanaz, E.; Sonestedt, E.; Ericson, U.; Schneede, J.; Guelpen, B. van; Wark, P.A.; Gallo, V.; Norat, T.; Riboli, E.; Vollset, S.E.

    2013-01-01

    Different lifestyle patterns across Europe may influence plasma concentrations of B-vitamins and one-carbon metabolites and their relation to chronic disease. Comparison of published data on one-carbon metabolites in Western European regions is difficult due to differences in sampling procedures and

  20. Constraining genome-scale models to represent the bow tie structure of metabolism for 13C metabolic flux analysis

    DEFF Research Database (Denmark)

    Backman, Tyler W.H.; Ando, David; Singh, Jahnavi

    2018-01-01

    for a minimum of fluxes into core metabolism to satisfy these experimental constraints. Together, these methods accelerate and automate the identification of a biologically reasonable set of core reactions for use with 13C MFA or 2S- 13C MFA, as well as provide for a substantially lower set of flux bounds......Determination of internal metabolic fluxes is crucial for fundamental and applied biology because they map how carbon and electrons flow through metabolism to enable cell function. 13C Metabolic Flux Analysis (13C MFA) and Two-Scale 13C Metabolic Flux Analysis (2S-13C MFA) are two techniques used...

  1. Carbohydrate Metabolism Disorders

    Science.gov (United States)

    ... metabolic disorder, something goes wrong with this process. Carbohydrate metabolism disorders are a group of metabolic disorders. Normally your enzymes break carbohydrates down into glucose (a type of sugar). If ...

  2. Comprehensive metabolic panel

    Science.gov (United States)

    Metabolic panel - comprehensive; Chem-20; SMA20; Sequential multi-channel analysis with computer-20; SMAC20; Metabolic panel 20 ... Chernecky CC, Berger BJ. Comprehensive metabolic panel (CMP) - blood. In: ... Tests and Diagnostic Procedures . 6th ed. St Louis, MO: ...

  3. Metabolic adjustment upon repetitive substrate perturbations using dynamic

    NARCIS (Netherlands)

    Suarez Mendez, C.A.; Ras, C.; Wahl, S.A.

    2017-01-01

    Background: Natural and industrial environments are dynamic with respect to substrate availability and other conditions like temperature and pH. Especially, metabolism is strongly affected by changes in the extracellular space. Here we study the dynamic flux of central carbon metabolism and

  4. Carbon 14

    International Nuclear Information System (INIS)

    2002-03-01

    Carbon 14 is one of the most abundant radionuclides of natural and artificial origin in the environment. The aim of this conference day organized by the French society of radioprotection (SFRP) was to take stock of our knowledge about this radionuclide (origins, production, measurement, management, effects on health..): state-of-the-art of 14 C metrology; dating use of 14 C; 14 C management and monitoring of the Hague site environment; Electricite de France (EdF) and 14 C; radiological and sanitary impact of 14 C contamination at the Ganagobie site (Haute-Provence, France); metabolism and biological effects of 14 C; 14 C behaviour in the marine environment near Cogema-La Hague plant; distribution of 14 C activities in waters, mud and sediments of the Loire river estuary; dynamical modeling of transfers in the aquatic and terrestrial environment of 14 C released by nuclear power plants in normal operation: human dose calculation using the Calvados model and application to the Loire river; 14 C distribution in continents; modeling of 14 C transfers in the terrestrial environment from atmospheric sources. (J.S.)

  5. Homocysteine metabolism and risk of schizophrenia

    NARCIS (Netherlands)

    Muntjewerff, J.W.

    2006-01-01

    The one-carbon cycle hypothesis initiated research of schizophrenia risk in relation to sensitive markers of aberrant homocysteine metabolism, such as B-vitamin concentrations, plasma total homocysteine (tHcy) concentrations, and genetic determinants. We observed decreased plasma and elevated RBC

  6. Biosynthesis and Metabolic Fate of Phenylalanine in Conifers

    OpenAIRE

    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 pheny...

  7. Integration of C1 and C2 Metabolism in Trees

    OpenAIRE

    Jardine, Kolby J.; Fernandes de Souza, Vinicius; Oikawa, Patty; Higuchi, Niro; Bill, Markus; Porras, Rachel; Niinemets, Ülo; Chambers, Jeffrey Q.

    2017-01-01

    C1 metabolism in plants is known to be involved in photorespiration, nitrogen and amino acid metabolism, as well as methylation and biosynthesis of metabolites and biopolymers. Although the flux of carbon through the C1 pathway is thought to be large, its intermediates are difficult to measure and relatively little is known about this potentially ubiquitous pathway. In this study, we evaluated the C1 pathway and its integration with the central metabolism using aqueous solutions of 13C-labele...

  8. Unveiling network-based functional features through integration of gene expression into protein networks.

    Science.gov (United States)

    Jalili, Mahdi; Gebhardt, Tom; Wolkenhauer, Olaf; Salehzadeh-Yazdi, Ali

    2018-06-01

    Decoding health and disease phenotypes is one of the fundamental objectives in biomedicine. Whereas high-throughput omics approaches are available, it is evident that any single omics approach might not be adequate to capture the complexity of phenotypes. Therefore, integrated multi-omics approaches have been used to unravel genotype-phenotype relationships such as global regulatory mechanisms and complex metabolic networks in different eukaryotic organisms. Some of the progress and challenges associated with integrated omics studies have been reviewed previously in comprehensive studies. In this work, we highlight and review the progress, challenges and advantages associated with emerging approaches, integrating gene expression and protein-protein interaction networks to unravel network-based functional features. This includes identifying disease related genes, gene prioritization, clustering protein interactions, developing the modules, extract active subnetworks and static protein complexes or dynamic/temporal protein complexes. We also discuss how these approaches contribute to our understanding of the biology of complex traits and diseases. This article is part of a Special Issue entitled: Cardiac adaptations to obesity, diabetes and insulin resistance, edited by Professors Jan F.C. Glatz, Jason R.B. Dyck and Christine Des Rosiers. Copyright © 2018 Elsevier B.V. All rights reserved.

  9. Gr and hp-1 tomato mutants unveil unprecedented interactions between arbuscular mycorrhizal symbiosis and fruit ripening.

    Science.gov (United States)

    Chialva, Matteo; Zouari, Inès; Salvioli, Alessandra; Novero, Mara; Vrebalov, Julia; Giovannoni, James J; Bonfante, Paola

    2016-07-01

    Systemic responses to an arbuscular mycorrhizal fungus reveal opposite phenological patterns in two tomato ripening mutants depending whether ethylene or light reception is involved. The availability of tomato ripening mutants has revealed many aspects of the genetics behind fleshy fruit ripening, plant hormones and light signal reception. Since previous analyses revealed that arbuscular mycorrhizal symbiosis influences tomato berry ripening, we wanted to test the hypothesis that an interplay might occur between root symbiosis and fruit ripening. With this aim, we screened seven tomato mutants affected in the ripening process for their responsiveness to the arbuscular mycorrhizal fungus Funneliformis mosseae. Following their phenological responses we selected two mutants for a deeper analysis: Green ripe (Gr), deficient in fruit ethylene perception and high-pigment-1 (hp-1), displaying enhanced light signal perception throughout the plant. We investigated the putative interactions between ripening processes, mycorrhizal establishment and systemic effects using biochemical and gene expression tools. Our experiments showed that both mutants, notwithstanding a normal mycorrhizal phenotype at root level, exhibit altered arbuscule functionality. Furthermore, in contrast to wild type, mycorrhization did not lead to a higher phosphate concentration in berries of both mutants. These results suggest that the mutations considered interfere with arbuscular mycorrhiza inducing systemic changes in plant phenology and fruits metabolism. We hypothesize a cross talk mechanism between AM and ripening processes that involves genes related to ethylene and light signaling.

  10. Qualitative ubiquitome unveils the potential significances of protein lysine ubiquitination in hyphal growth of Aspergillus nidulans.

    Science.gov (United States)

    Chu, Xin-Ling; Feng, Ming-Guang; Ying, Sheng-Hua

    2016-02-01

    Protein ubiquitination is an evolutionarily conserved post-translational modification process in eukaryotes, and it plays an important role in many biological processes. Aspergillus nidulans, a model filamentous fungus, contributes to our understanding of cellular physiology, metabolism and genetics, but its ubiquitination is not completely revealed. In this study, the ubiquitination sites in the proteome of A. nidulans were identified using a highly sensitive mass spectrometry combined with immuno-affinity enrichment of the ubiquitinated peptides. The 4816 ubiquitination sites were identified in 1913 ubiquitinated proteins, accounting for 18.1% of total proteins in A. nidulans. Bioinformatic analysis suggested that the ubiquitinated proteins associated with a number of biological functions and displayed various sub-cellular localisations. Meanwhile, seven motifs were revealed from the ubiquitinated peptides, and significantly over-presented in the different pathways. Comparison of the enriched functional catalogues indicated that the ubiquitination functions divergently during growth of A. nidulans and Saccharomyces cerevisiae. Additionally, the proteins in A. nidulans-specific sub-category (cell growth/morphogenesis) were subjected to the protein interaction analysis which demonstrated that ubiquitination is involved in the comprehensive protein interactions. This study presents a first proteomic view of ubiquitination in the filamentous fungus, and provides an initial framework for exploring the physiological roles of ubiquitination in A. nidulans.

  11. Early response of plant cell to carbon deprivation: in vivo 31P-NMR spectroscopy shows a quasi-instantaneous disruption on cytosolic sugars, phosphorylated intermediates of energy metabolism, phosphate partitioning, and intracellular pHs.

    Science.gov (United States)

    Gout, Elisabeth; Bligny, Richard; Douce, Roland; Boisson, Anne-Marie; Rivasseau, Corinne

    2011-01-01

    • In plant cells, sugar starvation triggers a cascade of effects at the scale of 1-2 days. However, very early metabolic response has not yet been investigated. • Soluble phosphorus (P) compounds and intracellular pHs were analysed each 2.5 min intervals in heterotrophic sycamore (Acer pseudoplatanus) cells using in vivo phosphorus nuclear magnetic resonance ((31)P-NMR). • Upon external-sugar withdrawal, the glucose 6-P concentration dropped in the cytosol, but not in plastids. The released inorganic phosphate (Pi) accumulated transiently in the cytosol before influx into the vacuole; nucleotide triphosphate concentration doubled, intracellular pH increased and cell respiration decreased. It was deduced that the cytosolic free-sugar concentration was low, corresponding to only 0.5 mM sucrose in sugar-supplied cells. • The release of sugar from the vacuole and from plastids is insufficient to fully sustain the cell metabolism during starvation, particularly in the very short term. Similarly to Pi-starvation, the cell's first response to sugar starvation occurs in the cytosol and is of a metabolic nature. Unlike the cytoplasm, cytosolic homeostasis is not maintained during starvation. The important metabolic changes following cytosolic sugar exhaustion deliver early endogenous signals that may contribute to trigger rescue metabolism. © The Authors (2010). Journal compilation © New Phytologist Trust (2010).

  12. Metabolic engineering in methanotrophic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Kalyuzhnaya, MG; Puri, AW; Lidstrom, ME

    2015-05-01

    Methane, as natural gas or biogas, is the least expensive source of carbon for (bio)chemical synthesis. Scalable biological upgrading of this simple alkane to chemicals and fuels can bring new sustainable solutions to a number of industries with large environmental footprints, such as natural gas/petroleum production, landfills, wastewater treatment, and livestock. Microbial biocatalysis with methane as a feedstock has been pursued off and on for almost a half century, with little enduring success. Today, biological engineering and systems biology provide new opportunities for metabolic system modulation and give new optimism to the concept of a methane-based bio-industry. Here we present an overview of the most recent advances pertaining to metabolic engineering of microbial methane utilization. Some ideas concerning metabolic improvements for production of acetyl-CoA and pyruvate, two main precursors for bioconversion, are presented. We also discuss main gaps in the current knowledge of aerobic methane utilization, which must be solved in order to release the full potential of methane-based biosystems. (C) 2015 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

  13. Modifying factors for metabolic parameters

    International Nuclear Information System (INIS)

    Inaba, Jiro

    1990-01-01

    Studies on factors which influence the metabolic parameter for calculation of radiation doses from intakes of radionuclides are very important for estimation of the doses for the general public, because the present procedures recommended by the International Commission on Radiological Protection is for occupationally exposed workers and the underlying metabolic and dosimetric models have been developed from studies on adult man and experiments on adult animals and from observations on radionuclides in physico-chemically simple form. Many factors have been reported to influence the metabolic parameters. Among them, the food-chain involvement of radionuclides and the age-dependence in humans and animals are most significant as environmental and physiological factor, respectively. In connection with the age-dependence of dose calculation, the ICRP started a new programme. They organized a Task Group on Age-Dependent Dose-Factors where relevant information on metabolic and biokinetic parameters are presently being reviewed for development of a set of dose factors for the following age-groups: infant, 1-year-old, 5-year-old, 10-year-old, 15-year-old, and ICRP Reference Man. The first stage of the work is for age-dependent integrated organ and effective dose factors for radioisotopes of the following elements: hydrogen, carbon, iodine, cesium, strontium, plutonium and americium. (author)

  14. Her Excellency Mrs Sarah Gillett Her Majesty's Ambassador to the Swiss Confederation United Kingdom of Great Britain and Northern Ireland on the occasion of the Antony Gormley sculpture unveiling ceremony Wednesday 7th December 2011

    CERN Document Server

    Maximilien Brice

    2011-01-01

    Her Excellency Mrs Sarah Gillett Her Majesty's Ambassador to the Swiss Confederation United Kingdom of Great Britain and Northern Ireland on the occasion of the Antony Gormley sculpture unveiling ceremony Wednesday 7th December 2011

  15. The metabolism of the Antartic crytoendolithic microbiota

    Science.gov (United States)

    Vestal, J. Robie

    1989-01-01

    The carbon metabolism of the cryptoendolithic microbiota in sandstones from the Ross Desert region of Antarctica was studied in situ and in vitro. Organic and inorganic compounds were metabolized by the microbiota, with bicarbonate being metabolized maximally in the light. There was a linear response of photosynthesis to light up to 200 to 300 micromole photons/sq m/s. The community photosynthetic response to temperature was a minimum at -5 C, two optima at +5 and +15 C and a maximum at +35 C. Photosynthetic metabolism occurred maximally in the presence of liquid water, but could occur in an environment of water vapor. Biomass of the cryptoendolithic microbiota was measured as the amount of lipid phosphate present. The in situ biomass ranged from 1.92 to 3.26 g carbon/sq m of rock and 2 orders of magnitude less than epilithic lichen microbiota from Antarctica in a location 7 degrees more north in latitude. With these data, it was possible to calculate primary production and carbon turnover in this simple microbiota. Production values ranged from 0.108 to 4.41 mg carbon/sq m/yr, while carbon turnover values ranged from 576 to 23,520 years. These values are the lowest and longest yet recorded for any ecosystem on Earth. If life did evolve on Mars to the level of prokaryotes or primitive eukaryotes, the possibility that the organisms retreated, to the protection of the inside of the rock so that metabolism could continue during planetary cooling, cannot be overlooked.

  16. IL-36/LXR axis modulates cholesterol metabolism and immune defense to Mycobacterium tuberculosis.

    Science.gov (United States)

    Ahsan, Fadhil; Maertzdorf, Jeroen; Guhlich-Bornhof, Ute; Kaufmann, Stefan H E; Moura-Alves, Pedro

    2018-01-24

    Mycobacterium tuberculosis (Mtb) is a life-threatening pathogen in humans. Bacterial infection of macrophages usually triggers strong innate immune mechanisms, including IL-1 cytokine secretion. The newer member of the IL-1 family, IL-36, was recently shown to be involved in cellular defense against Mtb. To unveil the underlying mechanism of IL-36 induced antibacterial activity, we analyzed its role in the regulation of cholesterol metabolism, together with the involvement of Liver X Receptor (LXR) in this process. We report that, in Mtb-infected macrophages, IL-36 signaling modulates cholesterol biosynthesis and efflux via LXR. Moreover, IL-36 induces the expression of cholesterol-converting enzymes and the accumulation of LXR ligands, such as oxysterols. Ultimately, both IL-36 and LXR signaling play a role in the regulation of antimicrobial peptides expression and in Mtb growth restriction. These data provide novel evidence for the importance of IL-36 and cholesterol metabolism mediated by LXR in cellular host defense against Mtb.

  17. Engineering microorganisms to increase ethanol production by metabolic redirection

    Science.gov (United States)

    Deng, Yu; Olson, Daniel G.; van Dijken, Johannes Pieter; Shaw, IV, Arthur J.; Argyros, Aaron; Barrett, Trisha; Caiazza, Nicky; Herring, Christopher D.; Rogers, Stephen R.; Agbogbo, Frank

    2017-10-31

    The present invention provides for the manipulation of carbon flux in a recombinant host cell to increase the formation of desirable products. The invention relates to cellulose-digesting organisms that have been genetically modified to allow the production of ethanol at a high yield by redirecting carbon flux at key steps of central metabolism.

  18. Recent progress in genetics, epigenetics and metagenomics unveils the pathophysiology of human obesity.

    Science.gov (United States)

    Pigeyre, Marie; Yazdi, Fereshteh T; Kaur, Yuvreet; Meyre, David

    2016-06-01

    In high-, middle- and low-income countries, the rising prevalence of obesity is the underlying cause of numerous health complications and increased mortality. Being a complex and heritable disorder, obesity results from the interplay between genetic susceptibility, epigenetics, metagenomics and the environment. Attempts at understanding the genetic basis of obesity have identified numerous genes associated with syndromic monogenic, non-syndromic monogenic, oligogenic and polygenic obesity. The genetics of leanness are also considered relevant as it mirrors some of obesity's aetiologies. In this report, we summarize ten genetically elucidated obesity syndromes, some of which are involved in ciliary functioning. We comprehensively review 11 monogenic obesity genes identified to date and their role in energy maintenance as part of the leptin-melanocortin pathway. With the emergence of genome-wide association studies over the last decade, 227 genetic variants involved in different biological pathways (central nervous system, food sensing and digestion, adipocyte differentiation, insulin signalling, lipid metabolism, muscle and liver biology, gut microbiota) have been associated with polygenic obesity. Advances in obligatory and facilitated epigenetic variation, and gene-environment interaction studies have partly accounted for the missing heritability of obesity and provided additional insight into its aetiology. The role of gut microbiota in obesity pathophysiology, as well as the 12 genes associated with lipodystrophies is discussed. Furthermore, in an attempt to improve future studies and merge the gap between research and clinical practice, we provide suggestions on how high-throughput '-omic' data can be integrated in order to get closer to the new age of personalized medicine. © 2016 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

  19. Patient perspectives about bariatric surgery unveil experiences, education, satisfaction, and recommendations for improvement.

    Science.gov (United States)

    Groller, Karen D; Teel, Cynthia; Stegenga, Kristin H; El Chaar, Maher

    2018-02-17

    Following bariatric surgery, up to 35% of patients struggle with strict regimens and experience weight recidivism within 2 years [1-5]. Accredited weight management centers (WMC) must provide educational programs and support patients in lifestyle changes before and after surgery. Educational programs, however, may not be evidence-based or patient-centered and may vary in curriculum, approach, and educator type [6]. To obtain patient descriptions about the weight loss surgery (WLS) experience, including education, satisfaction, and recommendations for improvement. Participants were recruited from a university hospital-based WMC in Pennsylvania. This qualitative descriptive study used purposive sampling and inductive content analysis. A NEW ME-VERSION 2.0, encompassed themes from semistructured interviews with 11 participants (36% male). Theme 1: Programming and Tools, explained how individuals undergoing WLS found support through educational programming. Theme 2: Updates and Upgrades, identified issues surrounding quality of life and challenges before and after surgery. Theme 3: Lessons Learned and Future Considerations, identified satisfaction levels and recommendations for improving the WLS experience. Participants reported positive experiences, acknowledging educational programs and extensive WMC resources, yet also offered recommendations for improving educational programming. Patient narratives provided evidence about the WLS experience. Achievement of weight goals, adherence to rules, and improved health status contributed to perceptions of WLS success. Participants encouraged educators to identify expected outcomes of educational programming, monitor holistic transformations, foster peer support, and use technology in WMC programming. Results also validated the need for the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program's education requirement (standard 5.1). Future educational research could help develop best practices in WLS

  20. Gas-rich galaxy pair unveiled in the lensed quasar 0957+561

    Science.gov (United States)

    Planesas; Martin-Pintado; Neri; Colina

    1999-12-24

    Molecular gas in the host galaxy of the lensed quasar 0957+561 (QSO 0957+561) at the redshift of 1.41 has been detected in the carbon monoxide (CO) line. This detection shows the extended nature of the molecular gas distribution in the host galaxy and the pronounced lensing effects due to the differentially magnified CO luminosity at different velocities. The estimated mass of molecular gas is about 4 x 10(9) solar masses, a molecular gas mass typical of a spiral galaxy like the Milky Way. A second, weaker component of CO is interpreted as arising from a close companion galaxy that is rich in molecular gas and has remained undetected so far. Its estimated molecular gas mass is 1.4 x 10(9) solar masses, and its velocity relative to the main galaxy is 660 kilometers per second. The ability to probe the molecular gas distribution and kinematics of galaxies associated with high-redshift lensed quasars can be used to improve the determination of the Hubble constant H(0).

  1. Unveiling the Role of CNTs on the Phase Formation of 1D Ferroelectrics

    KAUST Repository

    Mahajan, Amit

    2015-05-21

    Carbon nanotubes (CNTs) have the potential to act as templates or bottom electrodes for three dimension (3D) capacitor arrays, which utilise one dimension (1D) ferroelectric nanostructures to increase memory size and density. However, growing a ferroelectric on the surface of CNTs is non-trivial. Here, we demonstrate that multi-walled (MW) CNTs decrease the time and temperature for formation of lead zirconium titanate Pb(Zr1-xTix)O3 (PZT) by ~100 ºC commensurate with a decrease in activation energy from 68±15 kJ/mol to 27±2 kJ/mol. As a consequence, monophasic PZT was obtained at 575 ºC for MWCNTs/PZT whereas for pure PZT traces of pyrochlore were still present at 650 ºC, where PZT phase formed due to homogeneous nucleation. The piezoelectric nature of MWCNT/PZT synthesised at 500 ºC for 1 h was proved. Although further work is required to prove the concept of 3D capacitor arrays, our result suggests that it is feasible to utilise MWCNTs as templates/electrodes for the formation of 1D PZT nano ferroelectrics.

  2. Observability of plant metabolic networks is reflected in the correlation of metabolic profiles

    DEFF Research Database (Denmark)

    Schwahn, Kevin; Küken, Anika; Kliebenstein, Daniel James

    2016-01-01

    to obtain information about the entire system. Yet, the extent to which the data profiles reflect the role of components in the observability of the system remains unexplored. Here we first identify the sensor metabolites in the model plant Arabidopsis (Arabidopsis thaliana) by employing state...... with in silico generated metabolic profiles from a medium-size kinetic model of plant central carbon metabolism. Altogether, due to the small number of identified sensors, our study implies that targeted metabolite analyses may provide the vast majority of relevant information about plant metabolic systems....

  3. UPLC-QTOF/MS metabolic profiling unveils urinary changes in humans after a whole grain rye versus refined wheat bread intervention

    DEFF Research Database (Denmark)

    Bondia-Pons, Isabel; Barri, Thaer; Hanhineva, Kati

    2013-01-01

    Non-targeted urine metabolite profiling has not been previously exploited in the field of whole grain (WG) products. WG products, particularly rye, are important elements in a healthy Nordic diet. The aim of this study was to identify novel urinary biomarkers of WG rye bread (RB) intake in a rand......Non-targeted urine metabolite profiling has not been previously exploited in the field of whole grain (WG) products. WG products, particularly rye, are important elements in a healthy Nordic diet. The aim of this study was to identify novel urinary biomarkers of WG rye bread (RB) intake...

  4. A novel pathogenic aviadenovirus from red-bellied parrots (Poicephalus rufiventris) unveils deep recombination events among avian host lineages

    International Nuclear Information System (INIS)

    Das, Shubhagata; Fearnside, Kathleen; Sarker, Subir; Forwood, Jade K.; Raidal, Shane R.

    2017-01-01

    Competing roles of coevolution, selective pressure and recombination are an emerging interest in virus evolution. We report a novel aviadenovirus from captive red-bellied parrots (Poicephalus rufiventris) that uncovers evidence of deep recombination among aviadenoviruses. The sequence identity of the virus was most closely related to Turkey adenovirus D (42% similarity) and other adenoviruses in chickens, turkeys and pigeons. Sequencing and comparative analysis showed that the genome comprised 40,930 nucleotides containing 42 predicted open reading frames (ORFs) 19 of which had strong similarity with genes from other adenovirus species. The new genome unveiled a lineage that likely participated in deep recombination events across the genus Aviadenovirus accounting for an ancient evolutionary relationship. We hypothesize frequent host switch events and recombination among adenovirus progenitors in Galloanserae hosts caused the radiation of extant aviadenoviruses and the newly assembled Poicephalus adenovirus genome points to a potentially broader host range of these viruses among birds. - Highlights: •Shows how a single new genome can change overall phylogeny. •Reveals host switch events among adenovirus progenitors in Galloanserae hosts. •Points to a potentially broader host range of adenoviruses among birds and wildlife .

  5. A novel pathogenic aviadenovirus from red-bellied parrots (Poicephalus rufiventris) unveils deep recombination events among avian host lineages

    Energy Technology Data Exchange (ETDEWEB)

    Das, Shubhagata, E-mail: sdas@csu.edu.au [School of Animal and Veterinary Sciences, Faculty of Science, Charles Sturt University, New South Wales 2678 (Australia); Fearnside, Kathleen, E-mail: kathyfearnside@exemail.com.au [Hills District Veterinary Hospital, Unit 1, 276 New Line Road, Dural, NSW 2158 (Australia); Sarker, Subir, E-mail: S.Sarker@latrobe.edu.au [Department of Physiology, Anatomy and Microbiology, School of Life Sciences, La Trobe University, Melbourne, VIC 3086 (Australia); Forwood, Jade K., E-mail: jforwood@csu.edu.au [School of Biomedical Sciences, Faculty of Science, Charles Sturt University, Wagga Wagga, NSW 2650 (Australia); Raidal, Shane R., E-mail: shraidal@csu.edu.au [School of Animal and Veterinary Sciences, Faculty of Science, Charles Sturt University, New South Wales 2678 (Australia)

    2017-02-15

    Competing roles of coevolution, selective pressure and recombination are an emerging interest in virus evolution. We report a novel aviadenovirus from captive red-bellied parrots (Poicephalus rufiventris) that uncovers evidence of deep recombination among aviadenoviruses. The sequence identity of the virus was most closely related to Turkey adenovirus D (42% similarity) and other adenoviruses in chickens, turkeys and pigeons. Sequencing and comparative analysis showed that the genome comprised 40,930 nucleotides containing 42 predicted open reading frames (ORFs) 19 of which had strong similarity with genes from other adenovirus species. The new genome unveiled a lineage that likely participated in deep recombination events across the genus Aviadenovirus accounting for an ancient evolutionary relationship. We hypothesize frequent host switch events and recombination among adenovirus progenitors in Galloanserae hosts caused the radiation of extant aviadenoviruses and the newly assembled Poicephalus adenovirus genome points to a potentially broader host range of these viruses among birds. - Highlights: •Shows how a single new genome can change overall phylogeny. •Reveals host switch events among adenovirus progenitors in Galloanserae hosts. •Points to a potentially broader host range of adenoviruses among birds and wildlife .

  6. AMPK Activation Affects Glutamate Metabolism in Astrocytes

    DEFF Research Database (Denmark)

    Voss, Caroline Marie; Pajęcka, Kamilla; Stridh, Malin H

    2015-01-01

    acid (TCA) cycle was studied using high-performance liquid chromatography analysis supplemented with gas chromatography-mass spectrometry technology. It was found that AMPK activation had profound effects on the pathways involved in glutamate metabolism since the entrance of the glutamate carbon...... on glutamate metabolism in astrocytes was studied using primary cultures of these cells from mouse cerebral cortex during incubation in media containing 2.5 mM glucose and 100 µM [U-(13)C]glutamate. The metabolism of glutamate including a detailed analysis of its metabolic pathways involving the tricarboxylic...... skeleton into the TCA cycle was reduced. On the other hand, glutamate uptake into the astrocytes as well as its conversion to glutamine catalyzed by glutamine synthetase was not affected by AMPK activation. Interestingly, synthesis and release of citrate, which are hallmarks of astrocytic function, were...

  7. Global changes in transcription orchestrate metabolic differentiation during symbiotic nitrogen fixation in Lotus japonicus

    DEFF Research Database (Denmark)

    Colebatch, Gillian; Desbrosses, Guilhem; Ott, Thomas

    2004-01-01

    Research on legume nodule metabolism has contributed greatly to our knowledge of primary carbon and nitrogen metabolism in plants in general, and in symbiotic nitrogen fixation in particular. However, most previous studies focused on one or a few genes/enzymes involved in selected metabolic...

  8. Biosynthesis and metabolic fate of phenylalanine in conifers

    Directory of Open Access Journals (Sweden)

    María Belén Pascual

    2016-07-01

    Full Text Available 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.

  9. 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.

  10. Haloacetonitriles: metabolism and toxicity.

    Science.gov (United States)

    Lipscomb, John C; El-Demerdash, Ebtehal; Ahmed, Ahmed E

    2009-01-01

    The haloacetonitriles (HANs) exist in drinking water exclusively as byproducts of disinfection. HANs are found in drinking water more often, and in higher concentrations, when surface water is treated by chloramination. Human exposure occurs through consumption of finished drinking water; oral and dermal contact also occurs, and results from showering, swimming and other activities. HANs are reactive and are toxic to gastrointestinal tissues following oral administration. Such toxicity is characterized by GSH depletion, increased lipid peroxidation, and covalent binding of HAN-associated radioactivity to gut tissues. The presence of GSH in cells is an important protective mechanism against HAN toxicity; depletion of cellular GSH results in increased toxicity. Some studies have demonstrated an apparently synergistic effect between ROS and HAN administration, that may help explain effects observed in GI tissues. ROS are produced in gut tissues, and in vitro evidence indicates that ROS may contribute to the degradation and formation of reactive intermediates from HANs. The rationale for ROS involvement may involve HAN-induced depletion of GSH and the role of GSH in scavenging ROS. In addition to effects on GI tissues, studies show that HAN-derived radiolabel is found covalently bound to proteins and DNA in several organs and tissues. The addition of antioxidants to biologic systems protects against HAN-induced DNA damage. The protection offered by antioxidants supports the role of oxidative stress and the potential for a threshold in han-induced toxicity. However, additional data are needed to substantiate evidence for such a threshold. HANs are readily absorbed from the GI tract and are extensively metabolized. Elimination occurs primarily in urine, as unconjugated one-carbon metabolites. Evidence supports the involvement of mixed function oxidases, the cytochrome P450 enzyme family and GST, in HAN metabolism. Metabolism represents either a detoxification or

  11. Transcriptional and metabolic effects of glucose on Streptococcus pneumoniae sugar metabolism

    Directory of Open Access Journals (Sweden)

    Laura ePaixão

    2015-10-01

    Full Text Available Streptococcus pneumoniae is a strictly fermentative human pathogen that relies on carbohydrate metabolism to generate energy for growth. The nasopharynx colonised by the bacterium is poor in free sugars, but mucosa lining glycans can provide a source of sugar. In blood and inflamed tissues glucose is the prevailing sugar. As a result during progression from colonisation to disease S. pneumoniae has to cope with a pronounced shift in carbohydrate nature and availability. Thus, we set out to assess the pneumococcal response to sugars found in glycans and the influence of glucose (Glc on this response at the transcriptional, physiological and metabolic levels. Galactose (Gal, N-acetylglucosamine (GlcNAc and mannose (Man affected the expression of 8 to 14% of the genes covering cellular functions including central carbon metabolism and virulence. The pattern of end-products as monitored by in vivo 13C-NMR is in good agreement with the fermentation profiles during growth, while the pools of phosphorylated metabolites are consistent with the type of fermentation observed (homolactic vs. mixed and regulation at the metabolic level. Furthermore, the accumulation of α-Gal6P and Man6P indicate metabolic bottlenecks in the metabolism of Gal and Man, respectively. Glc added to cells actively metabolizing other sugar(s was readily consumed and elicited a metabolic shift towards a homolactic profile. The transcriptional response to Glc was large (over 5% of the genome. In central carbon metabolism (most represented category, Glc exerted mostly negative regulation. The smallest response to Glc was observed on a sugar mix, suggesting that exposure to varied sugars improves the fitness of S. pneumoniae. The expression of virulence factors was negatively controlled by Glc in a sugar-dependent manner. Overall, our results shed new light on the link between carbohydrate metabolism, adaptation to host niches and virulence.

  12. Transcriptional and metabolic effects of glucose on Streptococcus pneumoniae sugar metabolism.

    Science.gov (United States)

    Paixão, Laura; Caldas, José; Kloosterman, Tomas G; Kuipers, Oscar P; Vinga, Susana; Neves, Ana R

    2015-01-01

    Streptococcus pneumoniae is a strictly fermentative human pathogen that relies on carbohydrate metabolism to generate energy for growth. The nasopharynx colonized by the bacterium is poor in free sugars, but mucosa lining glycans can provide a source of sugar. In blood and inflamed tissues glucose is the prevailing sugar. As a result during progression from colonization to disease S. pneumoniae has to cope with a pronounced shift in carbohydrate nature and availability. Thus, we set out to assess the pneumococcal response to sugars found in glycans and the influence of glucose (Glc) on this response at the transcriptional, physiological, and metabolic levels. Galactose (Gal), N-acetylglucosamine (GlcNAc), and mannose (Man) affected the expression of 8 to 14% of the genes covering cellular functions including central carbon metabolism and virulence. The pattern of end-products as monitored by in vivo (13)C-NMR is in good agreement with the fermentation profiles during growth, while the pools of phosphorylated metabolites are consistent with the type of fermentation observed (homolactic vs. mixed) and regulation at the metabolic level. Furthermore, the accumulation of α-Gal6P and Man6P indicate metabolic bottlenecks in the metabolism of Gal and Man, respectively. Glc added to cells actively metabolizing other sugar(s) was readily consumed and elicited a metabolic shift toward a homolactic profile. The transcriptional response to Glc was large (over 5% of the genome). In central carbon metabolism (most represented category), Glc exerted mostly negative regulation. The smallest response to Glc was observed on a sugar mix, suggesting that exposure to varied sugars improves the fitness of S. pneumoniae. The expression of virulence factors was negatively controlled by Glc in a sugar-dependent manner. Overall, our results shed new light on the link between carbohydrate metabolism, adaptation to host niches and virulence.

  13. A state of the art of metabolic networks of unicellular microalgae and cyanobacteria for biofuel production.

    Science.gov (United States)

    Baroukh, Caroline; Muñoz-Tamayo, Rafael; Steyer, Jean-Philippe; Bernard, Olivier

    2015-07-01

    The most promising and yet challenging application of microalgae and cyanobacteria is the production of renewable energy: biodiesel from microalgae triacylglycerols and bioethanol from cyanobacteria carbohydrates. A thorough understanding of microalgal and cyanobacterial metabolism is necessary to master and optimize biofuel production yields. To this end, systems biology and metabolic modeling have proven to be very efficient tools if supported by an accurate knowledge of the metabolic network. However, unlike heterotrophic microorganisms that utilize the same substrate for energy and as carbon source, microalgae and cyanobacteria require light for energy and inorganic carbon (CO2 or bicarbonate) as carbon source. This double specificity, together with the complex mechanisms of light capture, makes the representation of metabolic network nonstandard. Here, we review the existing metabolic networks of photoautotrophic microalgae and cyanobacteria. We highlight how these networks have been useful for gaining insight on photoautotrophic metabolism. Copyright © 2015 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

  14. Understanding Regulation of Metabolism through Feasibility Analysis

    Science.gov (United States)

    Nikerel, Emrah; Berkhout, Jan; Hu, Fengyuan; Teusink, Bas; Reinders, Marcel J. T.; de Ridder, Dick

    2012-01-01

    Understanding cellular regulation of metabolism is a major challenge in systems biology. Thus far, the main assumption was that enzyme levels are key regulators in metabolic networks. However, regulation analysis recently showed that metabolism is rarely controlled via enzyme levels only, but through non-obvious combinations of hierarchical (gene and enzyme levels) and metabolic regulation (mass action and allosteric interaction). Quantitative analyses relating changes in metabolic fluxes to changes in transcript or protein levels have revealed a remarkable lack of understanding of the regulation of these networks. We study metabolic regulation via feasibility analysis (FA). Inspired by the constraint-based approach of Flux Balance Analysis, FA incorporates a model describing kinetic interactions between molecules. We enlarge the portfolio of objectives for the cell by defining three main physiologically relevant objectives for the cell: function, robustness and temporal responsiveness. We postulate that the cell assumes one or a combination of these objectives and search for enzyme levels necessary to achieve this. We call the subspace of feasible enzyme levels the feasible enzyme space. Once this space is constructed, we can study how different objectives may (if possible) be combined, or evaluate the conditions at which the cells are faced with a trade-off among those. We apply FA to the experimental scenario of long-term carbon limited chemostat cultivation of yeast cells, studying how metabolism evolves optimally. Cells employ a mixed strategy composed of increasing enzyme levels for glucose uptake and hexokinase and decreasing levels of the remaining enzymes. This trade-off renders the cells specialized in this low-carbon flux state to compete for the available glucose and get rid of over-overcapacity. Overall, we show that FA is a powerful tool for systems biologists to study regulation of metabolism, interpret experimental data and evaluate hypotheses. PMID

  15. From an equilibrium based MOF adsorbent to a kinetic selective