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Sample records for central carbon pathway

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

    DEFF Research Database (Denmark)

    Thamdrup, B; Canfield, Donald Eugene

    1996-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Bin Rui

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

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

    Science.gov (United States)

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

    2016-07-19

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

  4. Carbon-dependent control of electron transfer and central carbon pathway genes for methane biosynthesis in the Archaean, Methanosarcina acetivorans strain C2A

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    Gunsalus Robert P

    2010-02-01

    Full Text Available Abstract Background The archaeon, Methanosarcina acetivorans strain C2A forms methane, a potent greenhouse gas, from a variety of one-carbon substrates and acetate. Whereas the biochemical pathways leading to methane formation are well understood, little is known about the expression of the many of the genes that encode proteins needed for carbon flow, electron transfer and/or energy conservation. Quantitative transcript analysis was performed on twenty gene clusters encompassing over one hundred genes in M. acetivorans that encode enzymes/proteins with known or potential roles in substrate conversion to methane. Results The expression of many seemingly "redundant" genes/gene clusters establish substrate dependent control of approximately seventy genes for methane production by the pathways for methanol and acetate utilization. These include genes for soluble-type and membrane-type heterodisulfide reductases (hdr, hydrogenases including genes for a vht-type F420 non-reducing hydrogenase, molybdenum-type (fmd as well as tungsten-type (fwd formylmethanofuran dehydrogenases, genes for rnf and mrp-type electron transfer complexes, for acetate uptake, plus multiple genes for aha- and atp-type ATP synthesis complexes. Analysis of promoters for seven gene clusters reveal UTR leaders of 51-137 nucleotides in length, raising the possibility of both transcriptional and translational levels of control. Conclusions The above findings establish the differential and coordinated expression of two major gene families in M. acetivorans in response to carbon/energy supply. Furthermore, the quantitative mRNA measurements demonstrate the dynamic range for modulating transcript abundance. Since many of these gene clusters in M. acetivorans are also present in other Methanosarcina species including M. mazei, and in M. barkeri, these findings provide a basis for predicting related control in these environmentally significant methanogens.

  5. Improving Carbon Fixation Pathways

    OpenAIRE

    Ducat, Daniel C.; Silver, Pamela A

    2012-01-01

    A recent resurgence in basic and applied research on photosynthesis has been driven in part by recognition that fulfilling future food and energy requirements will necessitate improvements in crop carbon-fixation efficiencies. Photosynthesis in traditional terrestrial crops is being reexamined in light of molecular strategies employed by photosynthetic microbes to enhance the activity of the Calvin cycle. Synthetic biology is well-situated to provide original approaches for compartmentalizing...

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

    NARCIS (Netherlands)

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

    2014-01-01

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

  7. Water flow pathway and the organic carbon discharge during rain storm events in a coniferous forested head watershed, Tokyo, central Japan

    Science.gov (United States)

    Moriizumi, Mihoko; Terajima, Tomomi

    2010-05-01

    The current intense discussion of the green house effect, that has been one of the main focuses on the carbon cycle in environmental systems of the earth, seems to be weakened the importance related to the effect of carbonic materials on substance movement in the aquatic environments; though it has just begun to be referred recently. Because dissolved organic carbon (DOC) in stream flows believes to play a main role of the carbon cycle in the fresh water environment, seasonal changes in DOC discharge were investigated in catchments with various scale and land use, especially in forested catchments which are one of the important sources of DOC. In order to understand the fundamental characteristics of the discharge of dissolved organic materials, stream flows, DOC, and fulvic acid like materials (FA) included in stream flows were measured in a coniferous forested head watershed. The watershed is located at the southeast edge of the Kanto mountain and is 40 km west of Tokyo with the elevation from 720 to 820 m and mean slope gradient of 38 degrees. Geology of the watershed is underlain by the sequence of mud and sand stones in Jurassic and the soil in the watershed is Cambisol (Inceptisols). The watershed composes of a dense cypress and cedar forest of 45 years old with poor understory vegetation. Observations were carried out for 6 rain storms of which the total precipitations ranged between 16.2 and 117.4 mm. The magnitude of the storms was classified into small, middle, and big events on the basis of the total precipitation of around 20, 40, and more than 70 mm. Stream flows were collected during the storm events by 1 hour interval and were passed through the 0.45 μm filters, and then the DOC concentrations in the flows were measured with a total organic carbon analyzer. The relative concentrations of fulvic acid (FA) in the flows were monitored with three dimensional excitations emission matrix fluorescence spectroscopy, because fulvic acid shows distinctive

  8. Computational protein design enables a novel one-carbon assimilation pathway

    Energy Technology Data Exchange (ETDEWEB)

    Siegel, JB; Smith, AL; Poust, S; Wargacki, AJ; Bar-Even, A; Louw, C; Shen, BW; Eiben, CB; Tran, HM; Noor, E; Gallaher, JL; Bale, J; Yoshikuni, Y; Gelb, MH; Keasling, JD; Stoddard, BL; Lidstrom, ME; Baker, D

    2015-03-09

    We describe a computationally designed enzyme, formolase (FLS), which catalyzes the carboligation of three one-carbon formaldehyde molecules into one three-carbon dihydroxyacetone molecule. The existence of FLS enables the design of a new carbon fixation pathway, the formolase pathway, consisting of a small number of thermodynamically favorable chemical transformations that convert formate into a three-carbon sugar in central metabolism. The formolase pathway is predicted to use carbon more efficiently and with less backward flux than any naturally occurring one-carbon assimilation pathway. When supplemented with enzymes carrying out the other steps in the pathway, FLS converts formate into dihydroxyacetone phosphate and other central metabolites in vitro. These results demonstrate how modern protein engineering and design tools can facilitate the construction of a completely new biosynthetic pathway.

  9. Rewriting central metabolism for carbon conservation

    OpenAIRE

    Bogorad, Igor Walter

    2015-01-01

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

  10. A carbon sink pathway increases carbon productivity in cyanobacteria.

    Science.gov (United States)

    Oliver, John W K; Atsumi, Shota

    2015-05-01

    The burning of fossil reserves, and subsequent release of carbon into the atmosphere is depleting the supply of carbon-based molecules used for synthetic materials including plastics, oils, medicines, and glues. To provide for future society, innovations are needed for the conversion of waste carbon (CO2) into organic carbon useful for materials. Chemical production directly from photosynthesis is a nascent technology, with great promise for capture of CO2 using sunlight. To improve low yields, it has been proposed that photosynthetic capacity can be increased by a relaxation of bottlenecks inherent to growth. The limits of carbon partitioning away from growth within the cell and the effect of partitioning on carbon fixation are not well known. Here we show that expressing genes in a pathway between carbon fixation and pyruvate increases partitioning to 2,3-butanediol (23BD) and leads to a 1.8-fold increase in total carbon yield in the cyanobacterium Synechococcus elongatus PCC 7942. Specific 2,3-butanediol production increases 2.4-fold. As partitioning increases beyond 30%, it leads to a steep decline in total carbon yield. The data suggests a local maximum for carbon partitioning from the Calvin Benson cycle that is scalable with light intensity.

  11. Central mechanisms II: pharmacology of brainstem pathways.

    Science.gov (United States)

    Bolser, D C

    2009-01-01

    Following systemic administration, centrally acting antitussive drugs are generally assumed to act in the brainstem to inhibit cough. However, recent work in humans has raised the possibility of suprapontine sites of action for cough suppressants. For drugs that may act in the brainstem, the specific locations, types of neurones affected, and receptor specificities of the compounds represent important issues regarding their cough-suppressant actions. Two medullary areas that have received the most attention regarding the actions of antitussive drugs are the nucleus of the tractus solitarius (NTS) and the caudal ventrolateral respiratory column. Studies that have implicated these two medullary areas have employed both microinjection and in vitro recording methods to control the location of action of the antitussive drugs. Other brainstem regions contain neurones that participate in the production of cough and could represent potential sites of action of antitussive drugs. These regions include the raphe nuclei, pontine nuclei, and rostral ventrolateral medulla. Specific receptor subtypes have been associated with the suppression of cough at central sites, including 5-HT1A, opioid (mu, kappa, and delta), GABA-B, tachykinin neurokinin-1 (NK-1) and neurokinin-2, non-opioid (NOP-1), cannabinoid, dopaminergic, and sigma receptors. Aside from tachykinin NK-1 receptors in the NTS, relatively little is known regarding the receptor specificity of putative antitussive drugs in particular brainstem regions. Our understanding of the mechanisms of action of antitussive drugs would be significantly advanced by further work in this area. PMID:18825342

  12. The Central Carbon and Energy Metabolism of Marine Diatoms

    Directory of Open Access Journals (Sweden)

    Adriano Nunes-Nesi

    2013-05-01

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

  13. Central carbon metabolism in the progression of mammary carcinoma

    Science.gov (United States)

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

    2007-01-01

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

  14. Evaluating Soil Carbon Sequestration in Central Iowa

    Science.gov (United States)

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

    2005-12-01

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

  15. Estradiol and osmolality: Behavioral responses and central pathways.

    Science.gov (United States)

    Curtis, Kathleen S

    2015-12-01

    Regulation of appropriate osmolality of body fluid is critical for survival, yet there are sex differences in compensatory responses to osmotic challenges. Few studies have focused on the role of sex hormones such as estradiol in behavioral responses to increases or decreases in systemic osmolality, and even fewer studies have investigated whether central actions of estrogens contribute to these responses. This overview integrates findings from a series of ongoing and completed experiments conducted in my laboratory to assess estradiol effects on water and NaCl intake in response to osmotic challenges, and on activity in central pathways that mediate such responses.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-01-01

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

  17. Pathways to marriage and cohabitation in Central America

    Directory of Open Access Journals (Sweden)

    Kathryn Grace

    2014-01-01

    Full Text Available Background: The notion that increasing prevalence of cohabitation relative to marriage, and increasing age at first marriage are part of a broader shift in societal norms -- a second demographic transition -- is now well supported by studies focused on US and European populations. Recent research points to the similarly high prevalence of cohabitation in Latin America as perhaps signaling the diffusion of modern ideals and norms about union formation. In Central America this is unlikely to be the case given the long history and enduring acceptance of cohabitation that is unrelated to modern ideals. While there are studies that have documented this history and current prevalence, there is no research examining the intersecting life course pathways from adolescence through early adulthood that lead to marriage or cohabitation. This is not surprising given that available data for Central American countries are not ideally suited to studying the process. Methods: We use retrospective questions from large, nationally representative Central American surveys (Guatemala, Honduras, and Nicaragua to establish the timing of marriage or cohabitation and events that are closely tied to union formation. We utilize additive causespecific hazard models, and predicted transition probabilities based on selected covariate pathways, to study the competing risks of exiting from the status of never in union. Results: Our results identify sexual activity and pregnancy as the primary drivers of union formation and indicate that education serves as a protective factor against union formation. We also find distinct differences among countries and a strong indication that cohabitations are less stable unions.

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

    Science.gov (United States)

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

    2004-06-01

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

  19. Induction of cytoprotective pathways is central to the extension of lifespan conferred by multiple longevity pathways.

    Directory of Open Access Journals (Sweden)

    David E Shore

    Full Text Available Many genetic and physiological treatments that extend lifespan also confer resistance to a variety of stressors, suggesting that cytoprotective mechanisms underpin the regulation of longevity. It has not been established, however, whether the induction of cytoprotective pathways is essential for lifespan extension or merely correlated. Using a panel of GFP-fused stress response genes, we identified the suites of cytoprotective pathways upregulated by 160 gene inactivations known to increase Caenorhabditis elegans longevity, including the mitochondrial UPR (hsp-6, hsp-60, the ER UPR (hsp-4, ROS response (sod-3, gst-4, and xenobiotic detoxification (gst-4. We then screened for other gene inactivations that disrupt the induction of these responses by xenobiotic or genetic triggers, identifying 29 gene inactivations required for cytoprotective gene expression. If cytoprotective responses contribute directly to lifespan extension, inactivation of these genes would be expected to compromise the extension of lifespan conferred by decreased insulin/IGF-1 signaling, caloric restriction, or the inhibition of mitochondrial function. We find that inactivation of 25 of 29 cytoprotection-regulatory genes shortens the extension of longevity normally induced by decreased insulin/IGF-1 signaling, disruption of mitochondrial function, or caloric restriction, without disrupting normal longevity nearly as dramatically. These data demonstrate that induction of cytoprotective pathways is central to longevity extension and identify a large set of new genetic components of the pathways that detect cellular damage and couple that detection to downstream cytoprotective effectors.

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

    Science.gov (United States)

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

    2015-12-10

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

  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. Reconstruction of the central carbon metabolism of Aspergillus niger

    DEFF Research Database (Denmark)

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

    2003-01-01

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

  3. Carbon budgets and energy transition pathways

    NARCIS (Netherlands)

    Van Vuuren, Detlef P.; Van Soest, Heleen; Riahi, Keywan; Clarke, Leon; Krey, Volker; Kriegler, Elmar; Rogelj, Joeri; Schaeffer, Michiel; Tavoni, Massimo

    2016-01-01

    Scenarios from integrated assessment models can provide insights into how carbon budgets relate to other policy-relevant indicators by including information on how fast and by how much emissions can be reduced. Such indicators include the peak year of global emissions, the decarbonisation rate and t

  4. Carbon budgets and energy transition pathways

    NARCIS (Netherlands)

    Vuuren, Van Detlef P.; Soest, van Heleen; Riahi, Keywan; Clarke, Leon; Krey, Volker; Kriegler, Elmar; Rogelj, Joeri; Schaeffer, Michiel; Tavoni, Massimo

    2016-01-01

    Scenarios from integrated assessment models can provide insights into how carbon budgets relate to other policy-relevant indicators by including information on how fast and by how much emissions can be reduced. Such indicators include the peak year of global emissions, the decarbonisation rate an

  5. Carbon pathways in the Seine river system

    Science.gov (United States)

    Marescaux, Audrey; Garnier, Josette; Thieu, Vincent

    2016-04-01

    Many papers have recently suggested that the anthropogenic perturbations of the carbon cycle have led to a significant increase in carbon export from terrestrial ecosystems to inland waters. The quantification of the carbon cascade (including fate of CO2 emissions) in highly anthropized river systems is thus essential to understand the response of aquatic systems. The Seine Basin where Paris and its environs represent 2/3 of its population, and agriculture is particularly intensive, is a eutrophic system. The main aim of this research is to understand and quantify how an excess of anthropogenic nutrients entering the Seine River system may locally enhance primary production, C sequestration, C respiration and CO2 emissions. The development of a new CO2 module in the pre-existing biogeochemical Riverstrahler model (Billen et al., 2007) should enable a refined calculation of the carbon budget. Besides calculation of the Respiration and Production activities along the entire river continuum, it will directly associate CO2 emissions. The CO2 modelling results will be confronted to (i) direct (in-situ) measurements with a non-dispersive infrared gas analyzer and (ii) indirect measurements based on total alkalinity, carbonate and pH along the Seine river system during the last decades, and (iii) calculations of a C metabolism budget. Billen, G., Garnier, J., Némery, J., Sebilo, M., Sferratore, A., Barles, S., Benoit P., Benoît, M. (2007). A long-term view of nutrient transfers through the Seine river continuum. Science of the Total Environment, 375(1-3), 80-97. http://doi.org/10.1016/j.scitotenv.2006.12.005

  6. Phosphoketolase Pathway Engineering for Carbon-Efficient Biocatalysis

    Energy Technology Data Exchange (ETDEWEB)

    Henard, Calvin Andrew [National Renewable Energy Lab. (NREL), Golden, CO (United States); Freed, Emily Frances [National Renewable Energy Lab. (NREL), Golden, CO (United States); Guarnieri, Michael Thomas [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2015-09-08

    Recent advances in metabolic engineering have facilitated the development of microbial biocatalysts capable of producing an array of bio-products, ranging from fuels to drug molecules. These bio-products are commonly generated through an acetyl-CoA intermediate, which serves as a key precursor in the biological conversion of carbon substrates. Moreover, conventional biocatalytic upgrading strategies proceeding through this route are limited by low carbon efficiencies, in large part due to carbon losses associated with pyruvate decarboxylation to acetyl-CoA. Bypass of pyruvate decarboxylation offers a means to dramatically enhance carbon yields and, in turn, bioprocess economics. Here, we discuss recent advances and prospects for employing the phosphoketolase pathway for direct biosynthesis of acetyl-CoA from carbon substrates, and phosphoketolase-based metabolic engineering strategies for carbon efficient biocatalysis.

  7. Transitions in pathways of human development and carbon emissions

    International Nuclear Information System (INIS)

    Countries are known to follow diverse pathways of life expectancy and carbon emissions, but little is known about factors driving these dynamics. In this letter we estimate the cross-sectional economic, demographic and geographic drivers of consumption-based carbon emissions. Using clustering techniques, countries are grouped according to their drivers, and analysed with respect to a criteria of one tonne of carbon emissions per capita and a life expectancy over 70 years (Goldemberg’s Corner). Five clusters of countries are identified with distinct drivers and highly differentiated outcomes of life expectancy and carbon emissions. Representatives from four clusters intersect within Goldemberg’s Corner, suggesting diverse combinations of drivers may still lead to sustainable outcomes, presenting many countries with an opportunity to follow a pathway towards low-carbon human development. By contrast, within Goldemberg’s Corner, there are no countries from the core, wealthy consuming nations. These results reaffirm the need to address economic inequalities within international agreements for climate mitigation, but acknowledge plausible and accessible examples of low-carbon human development for countries that share similar underlying drivers of carbon emissions. In addition, we note differences in drivers between models of territorial and consumption-based carbon emissions, and discuss interesting exceptions to the drivers-based cluster analysis. (paper)

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

    Science.gov (United States)

    Freeman, Ralph D; Li, Baowang

    2016-10-01

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

  9. Pathways for implementing REDD+. Experiences from carbon markets and communities

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, X.; Ravnkilde Moeller, L.; Lopez, T. De; Romero, M.Z.

    2011-07-01

    This issue of Carbon Market Perspectives on 'Pathways for implementing REDD+: Experience from carbon markets and communities' discusses the role of carbon markets in scaling up investments for REDD+ in developing countries. Nine articles authored by experienced negotiators on REDD+, carbon market actors, project developers and other leading experts share experiences and make suggestions on the key elements of a future international REDD+ regime: Architecture and underlying principles, measuring, reporting and verification (MRV), private-sector involvement, the rights of indigenous people and local communities, biodiversity conservation and environmental integrity. The articles are grouped under three main topics: the lessons of existing REDD+ projects; the future REDD+ regime and the role of carbon markets; and experiences and ideas about the involvement of indigenous people and local communities. (LN)

  10. Pathways of human development and carbon emissions embodied in trade

    Science.gov (United States)

    Steinberger, Julia K.; Timmons Roberts, J.; Peters, Glen P.; Baiocchi, Giovanni

    2012-02-01

    It has long been assumed that human development depends on economic growth, that national economic expansion in turn requires greater energy use and, therefore, increased greenhouse-gas emissions. These interdependences are the topic of current research. Scarcely explored, however, is the impact of international trade: although some nations develop socio-economically and import high-embodied-carbon products, it is likely that carbon-exporting countries gain significantly fewer benefits. Here, we use new consumption-based measures of national carbon emissions to explore how the relationship between human development and carbon changes when we adjust national emission rates for trade. Without such adjustment of emissions, some nations seem to be getting far better development `bang' for the carbon `buck' than others, who are showing scant gains for disproportionate shares of global emissions. Adjusting for the transfer of emissions through trade explains many of these outliers, but shows that further socio-economic benefits are accruing to carbon-importing rather than carbon-exporting countries. We also find that high life expectancies are compatible with low carbon emissions but high incomes are not. Finally, we see that, despite strong international trends, there is no deterministic industrial development trajectory: there is great diversity in pathways, and national histories do not necessarily follow the global trends.

  11. Carbonate platform growth and demise offshore Central Vietnam

    DEFF Research Database (Denmark)

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

    2013-01-01

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

  12. Pathways of organic carbon oxidation in three continental margin sediments

    DEFF Research Database (Denmark)

    Canfield, Donald Eugene; Jørgensen, Bo Barker; Fossing, Henrik;

    1993-01-01

    that O2 respiration accounted for only between 3.6-17.4% of the total organic carbon oxidation. Dentrification was limited to a narrow zone just below the depth of O2 penetration, and was not a major carbon oxidation pathway. The processes of Fe reduction, Mn reduction and sulfate reduction dominated...... organic carbon mineralization, but their relative significance varied depending on the sediment. Where high concentrations of Mn-oxide were found (3-4 wt% Mn), only Mn reduction occurred. With lower Mn oxide concentrations more typical of coastal sediments, Fe reduction and sulfate reduction were most...... important and of a similar magnitude. Overall, most of the measured O2 flux into the sediment was used to oxidized reduced inorganic species and not organic carbon. We suspect that the importance of O2 respiration in many coastal sediments has been overestimated, whereas metal oxide reduction (both Fe...

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

    Science.gov (United States)

    Lininger, K.; Wohl, E.

    2014-12-01

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

  14. The effects of centrally injected arachidonic acid on respiratory system: Involvement of cyclooxygenase to thromboxane signaling pathway.

    Science.gov (United States)

    Erkan, Leman Gizem; Guvenc, Gokcen; Altinbas, Burcin; Niaz, Nasir; Yalcin, Murat

    2016-05-01

    Arachidonic acid (AA) is a polyunsaturated fatty acid that is present in the phospholipids of the cell membranes of the body and is abundant in the brain. Exogenously administered AA has been shown to affect brain metabolism and to exhibit cardiovascular and neuroendocrine actions. However, little is known regarding its respiratory actions and/or central mechanism of its respiratory effects. Therefore, the present study was designed to investigate the possible effects of centrally injected AA on respiratory system and the mediation of the central cyclooxygenase (COX) to thromboxane A2 (TXA2) signaling pathway on AA-induced respiratory effects in anaesthetized rats. Intracerebroventricular (i.c.v.) administration of AA induced dose- and time-dependent increase in tidal volume, respiratory rates and respiratory minute ventilation and also caused an increase in partial oxygen pressure (pO2) and decrease in partial carbon dioxide pressure (pCO2) in male anaesthetized Spraque Dawley rats. I.c.v. pretreatment with ibuprofen, a non-selective COX inhibitor, completely blocked the hyperventilation and blood gases changes induced by AA. In addition, central pretreatment with different doses of furegrelate, a TXA2 synthesis inhibitor, also partially prevented AA-evoked hyperventilation and blood gases effects. These data explicitly show that centrally administered AA induces hyperventilation with increasing pO2 and decreasing pCO2 levels which are mediated by the activation of central COX to TXA2 signaling pathway. PMID:26767978

  15. Dispersal limitation drives successional pathways in Central Siberian forests under current and intensified fire regimes.

    Science.gov (United States)

    Tautenhahn, Susanne; Lichstein, Jeremy W; Jung, Martin; Kattge, Jens; Bohlman, Stephanie A; Heilmeier, Hermann; Prokushkin, Anatoly; Kahl, Anja; Wirth, Christian

    2016-06-01

    Fire is a primary driver of boreal forest dynamics. Intensifying fire regimes due to climate change may cause a shift in boreal forest composition toward reduced dominance of conifers and greater abundance of deciduous hardwoods, with potential biogeochemical and biophysical feedbacks to regional and global climate. This shift has already been observed in some North American boreal forests and has been attributed to changes in site conditions. However, it is unknown if the mechanisms controlling fire-induced changes in deciduous hardwood cover are similar among different boreal forests, which differ in the ecological traits of the dominant tree species. To better understand the consequences of intensifying fire regimes in boreal forests, we studied postfire regeneration in five burns in the Central Siberian dark taiga, a vast but poorly studied boreal region. We combined field measurements, dendrochronological analysis, and seed-source maps derived from high-resolution satellite images to quantify the importance of site conditions (e.g., organic layer depth) vs. seed availability in shaping postfire regeneration. We show that dispersal limitation of evergreen conifers was the main factor determining postfire regeneration composition and density. Site conditions had significant but weaker effects. We used information on postfire regeneration to develop a classification scheme for successional pathways, representing the dominance of deciduous hardwoods vs. evergreen conifers at different successional stages. We estimated the spatial distribution of different successional pathways under alternative fire regime scenarios. Under intensified fire regimes, dispersal limitation of evergreen conifers is predicted to become more severe, primarily due to reduced abundance of surviving seed sources within burned areas. Increased dispersal limitation of evergreen conifers, in turn, is predicted to increase the prevalence of successional pathways dominated by deciduous hardwoods

  16. Pathways of organic carbon oxidation in three continental margin sediments

    Science.gov (United States)

    Canfield, D. E.; Jorgensen, B. B.; Fossing, H.; Glud, R.; Gundersen, J.; Ramsing, N. B.; Thamdrup, B.; Hansen, J. W.; Nielsen, L. P.; Hall, P. O.

    1993-01-01

    We have combined several different methodologies to quantify rates of organic carbon mineralization by the various electron acceptors in sediments from the coast of Denmark and Norway. Rates of NH4+ and Sigma CO2 liberation sediment incubations were used with O2 penetration depths to conclude that O2 respiration accounted for only between 3.6-17.4% of the total organic carbon oxidation. Dentrification was limited to a narrow zone just below the depth of O2 penetration, and was not a major carbon oxidation pathway. The processes of Fe reduction, Mn reduction and sulfate reduction dominated organic carbon mineralization, but their relative significance varied depending on the sediment. Where high concentrations of Mn-oxide were found (3-4 wt% Mn), only Mn reduction occurred. With lower Mn oxide concentrations more typical of coastal sediments, Fe reduction and sulfate reduction were most important and of a similar magnitude. Overall, most of the measured O2 flux into the sediment was used to oxidized reduced inorganic species and not organic carbon. We suspect that the importance of O2 respiration in many coastal sediments has been overestimated, whereas metal oxide reduction (both Fe and Mn reduction) has probably been well underestimated.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-08-13

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

  18. Pathways to marriage and cohabitation in Central America

    OpenAIRE

    Kathryn Grace; Stuart Sweeney

    2014-01-01

    Background: The notion that increasing prevalence of cohabitation relative to marriage, and increasing age at first marriage are part of a broader shift in societal norms -- a second demographic transition -- is now well supported by studies focused on US and European populations. Recent research points to the similarly high prevalence of cohabitation in Latin America as perhaps signaling the diffusion of modern ideals and norms about union formation. In Central America this is unlikely to be...

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

    Directory of Open Access Journals (Sweden)

    Papagianni Maria

    2012-04-01

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

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

    Science.gov (United States)

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

    2015-06-01

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

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

    Vedrova, É F

    2011-01-01

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

  3. Functional organisation of central cardiovascular pathways: studies using c-fos gene expression.

    Science.gov (United States)

    Dampney, R A L; Horiuchi, J

    2003-12-01

    Until about 10 years ago, knowledge of the functional organisation of the central pathways that subserve cardiovascular responses to homeostatic challenges and other stressors was based almost entirely on studies in anaesthetised animals. More recently, however, many studies have used the method of the expression of immediate early genes, particularly the c-fos gene, to identify populations of central neurons that are activated by such challenges in conscious animals. In this review we first consider the advantages and limitations of this method. Then, we discuss how the application of the method of immediate early gene expression, when used alone or in combination with other methods, has contributed to our understanding of the central mechanisms that regulate the autonomic and neuroendocrine response to various cardiovascular challenges (e.g., hypotension, hypoxia, hypovolemia, and other stressors) as they operate in the conscious state. In general, the results of studies of central cardiovascular pathways using immediate early gene expression are consistent with previous studies in anaesthetised animals, but in addition have revealed other previously unrecognised pathways that also contribute to cardiovascular regulation. Finally, we briefly consider recent evidence indicating that immediate early gene expression can modify the functional properties of central cardiovascular neurons, and the possible significance of this in producing long-term changes in the regulation of the cardiovascular system both in normal and pathological conditions.

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

    Science.gov (United States)

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

    2013-12-01

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

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

    International Nuclear Information System (INIS)

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

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

    Indian Academy of Sciences (India)

    S Banerjee; S K Bhattacharya; S Sarkar

    2006-02-01

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

  7. Turning sunlight into stone: the oxalate-carbonate pathway in a tropical tree ecosystem

    OpenAIRE

    G. Cailleau; Braissant, O; E. P. Verrecchia

    2011-01-01

    An African oxalogenic tree, the iroko tree (Milicia excelsa), has the property to enhance carbonate precipitation in tropical oxisols, where such accumulations are not expected due to the theoretical acidic conditions of these soils. This uncommon process is linked to the oxalate-carbonate pathway, which increases soil pH through oxalate oxidation. In order to investigate the oxalate-carbonate pathway in the iroko system, fluxes of matter have been identified, described, and evaluated from fi...

  8. Turning sunlight into stone: the oxalate-carbonate pathway in a tropical tree ecosystem

    OpenAIRE

    G. Cailleau; Braissant, O; E. P. Verrecchia

    2011-01-01

    An African oxalogenic tree, the iroko tree (Milicia excelsa), has the property to enhance carbonate precipitation in tropical oxisols, where such accumulations are not expected due to the acidic conditions in these types of soils. This uncommon process is linked to the oxalate-carbonate pathway, which increases soil pH through oxalate oxidation. In order to investigate the oxalate-carbonate pathway in the iroko system, fluxes of matter have been identified, described, and e...

  9. Pathways from and Crises after Communism: the Case of Central Eastern Europe

    Directory of Open Access Journals (Sweden)

    SZELENYI, Ivan

    2014-12-01

    Full Text Available The transition from socialist redistributive economy to capitalist markets has proved to be a rockier road that anticipated. The degree and character of difficulties that the countries faced during the transition depended on the nature of the pathways taken. In this paper I distinguish three major trajectories various countries followed: Central European neo-liberalism; post USSR neo-patrimonial regime and the East Asian (Chinese and Vietnamese transformation from below. Rather than distinguishing the “right way” from the “wrong way” I explore what the different costs and benefits of the various pathways were at various stages of the transformation.

  10. The Homogentisate Pathway: a Central Catabolic Pathway Involved in the Degradation of l-Phenylalanine, l-Tyrosine, and 3-Hydroxyphenylacetate in Pseudomonas putida

    OpenAIRE

    Arias-Barrau, Elsa; Olivera, Elías R.; Luengo, José M.; Fernández, Cristina; Galán, Beatriz; García, José L.; Díaz, Eduardo; Miñambres, Baltasar

    2004-01-01

    Pseudomonas putida metabolizes Phe and Tyr through a peripheral pathway involving hydroxylation of Phe to Tyr (PhhAB), conversion of Tyr into 4-hydroxyphenylpyruvate (TyrB), and formation of homogentisate (Hpd) as the central intermediate. Homogentisate is then catabolized by a central catabolic pathway that involves three enzymes, homogentisate dioxygenase (HmgA), fumarylacetoacetate hydrolase (HmgB), and maleylacetoacetate isomerase (HmgC), finally yielding fumarate and acetoacetate. Wherea...

  11. The Central Sirtuin 1/p53 Pathway Is Essential for the Orexigenic Action of Ghrelin

    OpenAIRE

    Velasquez, D. A.; Martinez, G.; Romero, A.; Vazquez, M. J.; Boit, K. D.; Dopeso-Reyes, I. G.; M. Lopez; Vidal, A.; Nogueiras, R.; Dieguez, C.

    2011-01-01

    OBJECTIVE Ghrelin is a stomach-derived peptide that increases food intake through the activation of hypothalamic AMP-activated protein kinase (AMPK). However, the molecular mechanisms initiated by the activation of the ghrelin receptor, which in turn lead to AMPK activation, remain unclear. Sirtuin 1 (SIRT1) is a deacetylase activated in response to calorie restriction that acts through the tumor suppressor gene p53. We tested the hypothesis that the central SIRT1/p53 pathway might be mediati...

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

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-11-15

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

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

    Directory of Open Access Journals (Sweden)

    Todd M Gibson

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

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

    Science.gov (United States)

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

    2013-04-01

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

  15. Avoiding, transforming, transitioning: pathways to sustainable low carbon passenger transport in developing countries

    DEFF Research Database (Denmark)

    Meza, Maria Josefina Figueroa; Fulton, Lewis; Tiwari, Geetam;

    2013-01-01

    This review examines conditions affecting road passenger transport in developing countries that can be instrumental to building a pathway for reducing carbon emissions while concurrently meeting sustainable development goals. By contrasting present and future status of these conditions a vision...

  16. Emergence of tuning to natural stimulus statistics along the central auditory pathway.

    Directory of Open Access Journals (Sweden)

    Jose A Garcia-Lazaro

    Full Text Available We have previously shown that neurons in primary auditory cortex (A1 of anaesthetized (ketamine/medetomidine ferrets respond more strongly and reliably to dynamic stimuli whose statistics follow "natural" 1/f dynamics than to stimuli exhibiting pitch and amplitude modulations that are faster (1/f(0.5 or slower (1/f(2 than 1/f. To investigate where along the central auditory pathway this 1/f-modulation tuning arises, we have now characterized responses of neurons in the central nucleus of the inferior colliculus (ICC and the ventral division of the mediate geniculate nucleus of the thalamus (MGV to 1/f(γ distributed stimuli with γ varying between 0.5 and 2.8. We found that, while the great majority of neurons recorded from the ICC showed a strong preference for the most rapidly varying (1/f(0.5 distributed stimuli, responses from MGV neurons did not exhibit marked or systematic preferences for any particular γ exponent. Only in A1 did a majority of neurons respond with higher firing rates to stimuli in which γ takes values near 1. These results indicate that 1/f tuning emerges at forebrain levels of the ascending auditory pathway.

  17. Poliovirus trafficking toward central nervous system via human poliovirus receptor-dependent and -independent pathway.

    Directory of Open Access Journals (Sweden)

    Seii eOHKA

    2012-04-01

    Full Text Available In humans, paralytic poliomyelitis results from the invasion of the central nervous system by circulating poliovirus (PV via the blood-brain barrier (BBB. After the virus enters the central nervous system (CNS, it replicates in neurons, especially in motor neurons (MNs, inducing the cell death that causes paralytic poliomyelitis. Along with this route of dissemination, neural pathway has been reported in humans, monkeys, and PV-sensitive human PV receptor (hPVR/CD155-transgenic (Tg mice. We demonstrated that a fast retrograde axonal transport process is required for PV dissemination through the sciatic nerve of hPVR-Tg mice and that intramuscularly inoculated PV causes paralysis in a hPVR-dependent manner. We also showed that hPVR-independent axonal transport of PV exists in hPVR-Tg and non-Tg mice, indicating that several different pathways for PV axonal transport exist in these mice. Circulating PV after intravenous inoculation in mice cross the BBB at a high rate in a hPVR-independent manner. Recently, we identified transferrin receptor 1 (TfR1 of mouse brain capillary endothelial cells as a binding protein to PV, implicating that TfR1 is a possible receptor for PV to permeate the BBB.

  18. Turning sunlight into stone: the oxalate-carbonate pathway in a tropical tree ecosystem

    Directory of Open Access Journals (Sweden)

    G. Cailleau

    2011-07-01

    Full Text Available An African oxalogenic tree, the iroko tree (Milicia excelsa, has the property to enhance carbonate precipitation in tropical oxisols, where such accumulations are not expected due to the acidic conditions in these types of soils. This uncommon process is linked to the oxalate-carbonate pathway, which increases soil pH through oxalate oxidation. In order to investigate the oxalate-carbonate pathway in the iroko system, fluxes of matter have been identified, described, and evaluated from field to microscopic scales. In the first centimeters of the soil profile, decaying of the organic matter allows the release of whewellite crystals, mainly due to the action of termites and saprophytic fungi. In addition, a concomitant flux of carbonate formed in wood tissues contributes to the carbonate flux and is identified as a direct consequence of wood feeding by termites. Nevertheless, calcite biomineralization of the tree is not a consequence of in situ oxalate consumption, but rather related to the oxalate oxidation inside the upper part of the soil. The consequence of this oxidation is the presence of carbonate ions in the soil solution pumped through the roots, leading to preferential mineralization of the roots and the trunk base. An ideal scenario for the iroko biomineralization and soil carbonate accumulation starts with oxalatization: as the iroko tree grows, the organic matter flux to the soil constitutes the litter, and an oxalate pool is formed on the forest ground. Then, wood rotting agents (mainly termites, saprophytic fungi, and bacteria release significant amounts of oxalate crystals from decaying plant tissues. In addition, some of these agents are themselves producers of oxalate (e.g. fungi. Both processes contribute to a soil pool of "available" oxalate crystals. Oxalate consumption by oxalotrophic bacteria can then start. Carbonate and calcium ions present in the soil solution represent the end products of the oxalate-carbonate

  19. Turning sunlight into stone: the oxalate-carbonate pathway in a tropical tree ecosystem

    Directory of Open Access Journals (Sweden)

    G. Cailleau

    2011-02-01

    Full Text Available An African oxalogenic tree, the iroko tree (Milicia excelsa, has the property to enhance carbonate precipitation in tropical oxisols, where such accumulations are not expected due to the theoretical acidic conditions of these soils. This uncommon process is linked to the oxalate-carbonate pathway, which increases soil pH through oxalate oxidation. In order to investigate the oxalate-carbonate pathway in the iroko system, fluxes of matter have been identified, described, and evaluated from field to microscopic scales. In the first centimeters of the soil profile, decaying of the organic matter allows the release of whewellite crystals, mainly due to the action of termites and saprophytic fungi. Regarding the carbonate flux, another direct consequence of wood feeding is a concomitant flux of carbonate formed in wood tissues, which is not consumed by termites. Nevertheless, calcite biomineralization of the tree is not a consequence of in situ oxalate consumption, but rather related to the oxalate oxidation inside the upper part of the soil. The consequence of this oxidation is the presence of carbonate ions in the soil solution pumped through the roots, leading to preferential mineralization of the roots and the trunk base. An ideal scenario for the iroko biomineralization and soil carbonate accumulation starts with oxalatization: as the iroko tree grows, the organic matter flux to the soil constitutes the litter. Therefore, an oxalate pool is formed on the forest ground. Then, wood rotting gents (mainly termites, fungi, and bacteria release significant amounts of oxalate crystals from decaying plant tissues. In addition some of these gents are themselves producers of oxalate (fungi. Both processes contribute to a soil pool of "available" oxalate crystals. Oxalate consumption by oxalotrophic bacteria can start. Carbonate and calcium ions present in the soil solution represent the end products of the oxalate-carbonate pathway. The solution is pumped

  20. Turning sunlight into stone: the oxalate-carbonate pathway in a tropical tree ecosystem

    Science.gov (United States)

    Cailleau, G.; Braissant, O.; Verrecchia, E. P.

    2011-07-01

    An African oxalogenic tree, the iroko tree (Milicia excelsa), has the property to enhance carbonate precipitation in tropical oxisols, where such accumulations are not expected due to the acidic conditions in these types of soils. This uncommon process is linked to the oxalate-carbonate pathway, which increases soil pH through oxalate oxidation. In order to investigate the oxalate-carbonate pathway in the iroko system, fluxes of matter have been identified, described, and evaluated from field to microscopic scales. In the first centimeters of the soil profile, decaying of the organic matter allows the release of whewellite crystals, mainly due to the action of termites and saprophytic fungi. In addition, a concomitant flux of carbonate formed in wood tissues contributes to the carbonate flux and is identified as a direct consequence of wood feeding by termites. Nevertheless, calcite biomineralization of the tree is not a consequence of in situ oxalate consumption, but rather related to the oxalate oxidation inside the upper part of the soil. The consequence of this oxidation is the presence of carbonate ions in the soil solution pumped through the roots, leading to preferential mineralization of the roots and the trunk base. An ideal scenario for the iroko biomineralization and soil carbonate accumulation starts with oxalatization: as the iroko tree grows, the organic matter flux to the soil constitutes the litter, and an oxalate pool is formed on the forest ground. Then, wood rotting agents (mainly termites, saprophytic fungi, and bacteria) release significant amounts of oxalate crystals from decaying plant tissues. In addition, some of these agents are themselves producers of oxalate (e.g. fungi). Both processes contribute to a soil pool of "available" oxalate crystals. Oxalate consumption by oxalotrophic bacteria can then start. Carbonate and calcium ions present in the soil solution represent the end products of the oxalate-carbonate pathway. The solution is

  1. Tissue factor pathway inhibitor-2: a novel gene involved in zebrafish central nervous system development.

    Science.gov (United States)

    Zhang, Yanli; Wang, Lina; Zhou, Wenhao; Wang, Huijun; Zhang, Jin; Deng, Shanshan; Li, Weihua; Li, Huawei; Mao, Zuohua; Ma, Duan

    2013-09-01

    Tissue factor pathway inhibitor-2 (Tfpi-2) is an important serine protease inhibitor in the extracellular matrix (ECM), but its precise physiological significance remains unknown. This work is part of a series of studies intended to investigate functional roles of Tfpi-2 and explore the underlying molecular mechanisms. First, we cloned and identified zebrafish Tfpi-2 (zTfpi-2) as an evolutionarily conserved protein essential for zebrafish development. We also demonstrated that ztfpi-2 is mainly expressed in the central nervous system (CNS) of zebrafish, and embryonic depletion of ztfpi-2 caused severe CNS defects. In addition, changes of neural markers, including pax2a, egr2b, huC, ngn1, gfap and olig2, confirmed the presence of developmental abnormalities in the relevant regions of ztfpi-2 morphants. Using microarray analysis, we found that members of the Notch pathway, especially her4 and mib, which mediate lateral inhibition in CNS development, were also downregulated. Intriguingly, both her4 and mib were able to partially rescue the ztfpi-2 morphant phenotype. Furthermore, Morpholino knockdown of ztfpi-2 resulted in upregulation of neuronal markers while downregulation of glial markers, providing evidence that the Notch pathway is probably involved in ztfpi-2-mediated CNS development.

  2. Demonstration of prosthetic activation of central auditory pathways using ( sup 14 C)-2-deoxyglucose

    Energy Technology Data Exchange (ETDEWEB)

    Evans, D.A.; Niparko, J.K.; Altschuler, R.A.; Frey, K.A.; Miller, J.M. (Univ. of Michigan Medical Center, Ann Arbor (USA))

    1990-02-01

    The cochlear prosthesis is not applicable to patients who lack an implantable cochlea or an intact vestibulocochlear nerve. Direct electrical stimulation of the cochlear nucleus (CN) of the brain stem might provide a method for auditory rehabilitation of these patients. A penetrating CN electrode has been developed and tissue tolerance to this device demonstrated. This study was undertaken to evaluate metabolic activation of central nervous system (CNS) auditory tracts produced by such implants. Regional cerebral glucose use resulting from CN stimulation was estimated in a series of chronically implanted guinea pigs with the use of ({sup 14}C)-2-deoxyglucose (2-DG). Enhanced 2-DG uptake was observed in structures of the auditory tract. The activation of central auditory structures achieved with CN stimulation was similar to that produced by acoustic stimulation and by electrical stimulation of the modiolar portion of the auditory nerve in control groups. An interesting banding pattern was observed in the inferior colliculus following CN stimulation, as previously described with acoustic stimulation. This study demonstrates that functional metabolic activation of central auditory pathways can be achieved with a penetrating CNS auditory prosthesis.

  3. Funding pathways to a low-carbon transition

    Science.gov (United States)

    Foulds, Chris; Christensen, Toke Haunstrup

    2016-07-01

    The framing of funding programmes can sustain existing ways of conceptualizing particular problems, as well as create new ones. Yet, without more prominent roles for social sciences and humanities, the techno-economic conceptualization of energy consumers could hinder long-term low-carbon aspirations.

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

    Directory of Open Access Journals (Sweden)

    Claudio Riccomini

    2007-09-01

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

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

    NARCIS (Netherlands)

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

    2013-01-01

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

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

    Digital Repository Service at National Institute of Oceanography (India)

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

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

  7. Advances in mechanisms and signaling pathways of carbon nanotube toxicity

    OpenAIRE

    Dong, Jie; Ma, Qiang

    2015-01-01

    Carbon nanotubes (CNT) have been developed into new materials with a variety of industrial and commercial applications. In contrast, the physicochemical properties of CNT at the nanoscale render them the potency to generate toxic effects. Indeed, the potential health impacts of CNT have drawn a great deal of attention in recent years, owing to their identified toxicological and pathological consequences including cytotoxicity, inflammation, fibrosis, genotoxicity, tumorigenesis, and immunotox...

  8. Pathogens penetrating the central nervous system: infection pathways and the cellular and molecular mechanisms of invasion.

    Science.gov (United States)

    Dando, Samantha J; Mackay-Sim, Alan; Norton, Robert; Currie, Bart J; St John, James A; Ekberg, Jenny A K; Batzloff, Michael; Ulett, Glen C; Beacham, Ifor R

    2014-10-01

    The brain is well protected against microbial invasion by cellular barriers, such as the blood-brain barrier (BBB) and the blood-cerebrospinal fluid barrier (BCSFB). In addition, cells within the central nervous system (CNS) are capable of producing an immune response against invading pathogens. Nonetheless, a range of pathogenic microbes make their way to the CNS, and the resulting infections can cause significant morbidity and mortality. Bacteria, amoebae, fungi, and viruses are capable of CNS invasion, with the latter using axonal transport as a common route of infection. In this review, we compare the mechanisms by which bacterial pathogens reach the CNS and infect the brain. In particular, we focus on recent data regarding mechanisms of bacterial translocation from the nasal mucosa to the brain, which represents a little explored pathway of bacterial invasion but has been proposed as being particularly important in explaining how infection with Burkholderia pseudomallei can result in melioidosis encephalomyelitis.

  9. The oxalate-carbonate pathway: at the interface between biology and geology

    Science.gov (United States)

    Junier, P.; Cailleau, G.; Martin, G.; Guggiari, M.; Bravo, D.; Clerc, M.; Aragno, M.; Job, D.; Verrecchia, E.

    2012-04-01

    The formation of calcite in otherwise carbonate-free acidic soils through the biological degradation of oxalate is a mechanism termed oxalate-carbonate pathway. This pathway lies at the interface between biological and geological systems and constitutes an important, although underestimated, soil mineral carbon sink. In this case, atmospheric CO2 is fixed by the photosynthetic activity of oxalogenic plants, which is partly destined to the production of oxalate used for the chelation of metals, and particularly, calcium. Fungi are also able to produce oxalate to cope with elevated concentrations of metals. In spite of its abundance as a substrate, oxalate is a very stable organic anion that can be metabolized only by a group of bacteria that use it as carbon and energy sources. These bacteria close the biological cycle by degrading calcium oxalate, releasing Ca2+ and inducing a change in local soil pH. If parameters are favourable, the geological part of the pathway begins, because this change in pH will indirectly lead to the precipitation of secondary calcium carbonate (calcite) in unexpected geological conditions. Due to the initial acidic soil conditions, and the absence of geological carbonate in the basement, it is unexpected to find C in the form of calcite. The activity of the oxalate-carbonate pathway has now been demonstrated in several places around the world, suggesting that its importance can be even greater than expected. In addition, new roles for each of the biological players of the pathway have been revealed recently forcing us to reconsider a global biogeochemical model for oxalate cycling.

  10. Same same but different. Different trigeminal chemoreceptors share the same central pathway.

    Directory of Open Access Journals (Sweden)

    Kathrin Kollndorfer

    Full Text Available Intranasal trigeminal sensations are important in everyday life of human beings, as they play a governing role in protecting the airways from harm. Trigeminal sensations arise from the binding of a ligand to various sub-types of transient receptor potential (TRP channels located on mucosal branches of the trigeminal nerve. Which underlying neural networks are involved in the processing of various trigeminal inputs is still unknown. To target this unresolved question fourteen healthy human subjects were investigated by completing three functional magnetic resonance imaging (fMRI scanning sessions during which three trigeminal substances, activating varying sub-types of chemoreceptors and evoking different sensations in the nose were presented: CO2, menthol and cinnamaldehyde. We identified similar functional networks responding to all stimuli: an olfactory network, a somatosensory network and an integrative network. The processing pathway of all three stimulants was represented by the same functional networks, although CO2 evokes painful but virtually odorless sensations, and the two other stimulants, menthol and cinnamaldehyde are perceived as mostly non painful with a clear olfactory percept. Therefore, our results suggest a common central processing pathway for trigeminal information regardless of the trigeminal chemoreceptor and sensation type.

  11. Same same but different. Different trigeminal chemoreceptors share the same central pathway.

    Science.gov (United States)

    Kollndorfer, Kathrin; Kowalczyk, Ksenia; Frasnelli, Johannes; Hoche, Elisabeth; Unger, Ewald; Mueller, Christian A; Krajnik, Jacqueline; Trattnig, Siegfried; Schöpf, Veronika

    2015-01-01

    Intranasal trigeminal sensations are important in everyday life of human beings, as they play a governing role in protecting the airways from harm. Trigeminal sensations arise from the binding of a ligand to various sub-types of transient receptor potential (TRP) channels located on mucosal branches of the trigeminal nerve. Which underlying neural networks are involved in the processing of various trigeminal inputs is still unknown. To target this unresolved question fourteen healthy human subjects were investigated by completing three functional magnetic resonance imaging (fMRI) scanning sessions during which three trigeminal substances, activating varying sub-types of chemoreceptors and evoking different sensations in the nose were presented: CO2, menthol and cinnamaldehyde. We identified similar functional networks responding to all stimuli: an olfactory network, a somatosensory network and an integrative network. The processing pathway of all three stimulants was represented by the same functional networks, although CO2 evokes painful but virtually odorless sensations, and the two other stimulants, menthol and cinnamaldehyde are perceived as mostly non painful with a clear olfactory percept. Therefore, our results suggest a common central processing pathway for trigeminal information regardless of the trigeminal chemoreceptor and sensation type.

  12. MPTP's pathway of toxicity indicates central role of transcription factor SP1.

    Science.gov (United States)

    Maertens, Alexandra; Luechtefeld, Thomas; Kleensang, Andre; Hartung, Thomas

    2015-05-01

    Deriving a Pathway of Toxicity from transcriptomic data remains a challenging task. We explore the use of weighted gene correlation network analysis (WGCNA) to extract an initial network from a small microarray study of MPTP toxicity in mice. Five modules were statistically significant; each module was analyzed for gene signatures in the Chemical and Genetic Perturbation subset of the Molecular Signatures Database as well as for over-represented transcription factor binding sites and WGCNA clustered probes by function and captured pathways relevant to neurodegenerative disorders. The resulting network was analyzed for transcription factor candidates, which were narrowed down via text-mining for relevance to the disease model, and then combined with the large-scale interaction FANTOM4 database to generate a genetic regulatory network. Modules were enriched for transcription factors relevant to Parkinson's disease. Transcription factors significantly improved the number of genes that could be connected in a given component. For each module, the transcription factor that had, by far, the highest number of interactions was SP1, and it also had substantial experimental evidence of interactions. This analysis both captures much of the known biology of MPTP toxicity and suggests several candidates for further study. Furthermore, the analysis strongly suggests that SP1 plays a central role in coordinating the cellular response to MPTP toxicity. PMID:25851821

  13. Funding pathways to a low-carbon transition

    DEFF Research Database (Denmark)

    Foulds, Chris; Christensen, Toke Haunstrup

    2016-01-01

    The framing of funding programmes can sustain existing ways of conceptualizing particular problems, as well as create new ones. Yet, without more prominent roles for social sciences and humanities, the techno-economic conceptualization of energy consumers could hinder long-term low-carbon aspirat......The framing of funding programmes can sustain existing ways of conceptualizing particular problems, as well as create new ones. Yet, without more prominent roles for social sciences and humanities, the techno-economic conceptualization of energy consumers could hinder long-term low...

  14. Non-riverine pathways of terrigenous carbon to the ocean

    Science.gov (United States)

    Dittmar, T.

    2007-12-01

    The extent and nature of non-riverine fluxes of carbon from land to ocean are poorly understood. Tidal pumping from highly productive coastal environments, atmospheric deposition and submarine groundwater discharge can be significant transport mechanisms for carbon to the ocean. Evidence is mounting that tidally-induced porewater fluxes ("outwelling") of dissolved organic matter (DOM) from mangroves and salt marshes alone may be similar in magnitude as the global riverine flux of DOM. Tidal pumping of dissolved inorganic carbon (DIC) might exceed organic carbon fluxes by far, but the existing knowledge on DIC outwelling is too scarce for a first global estimate. Results from two case studies on the biogeochemistry of DOM outwelling are presented, from the mangroves in Northern Brazil and the salt marshes in the Northern Gulf of Mexico. Ongoing research in the Northern Gulf of Mexico indicates that outwelling and groundwater inputs probably exceed riverine DOM fluxes in this region. Similar observations were made in Northern Brazil. There, the fate of mangrove-derived DOM could be traced from its source in the mangrove sediments to the outer North Brazil shelf by using a combination of isotopic and molecular approaches. Reversed-phase liquid chromatography / mass spectrometry (LC/MS) provided a multifaceted array of information that mirrors the molecular complexity of DOM. Statistical analyses on these data revealed significant differences between mangrove and open-ocean DOM which successively disappeared by irradiating the samples with natural sunlight. Nuclear magnetic resonance analyses yielded concurrent results. Ultrahigh-resolution Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS) is the only technique capable of resolving and identifying individual elemental compositions in these complex mixtures. We applied this technique for characterizing mangrove-derived DOM and to assess the molecular changes that occur in the initial stages of

  15. Activation of locus coeruleus heme oxygenase-carbon monoxide pathway promoted an anxiolytic-like effect in rats.

    Science.gov (United States)

    Carvalho-Costa, P G; Branco, L G S; Leite-Panissi, C R A

    2016-01-01

    The heme oxygenase-carbon monoxide pathway has been shown to play an important role in many physiological processes and is capable of altering nociception modulation in the nervous system by stimulating soluble guanylate cyclase (sGC). In the central nervous system, the locus coeruleus (LC) is known to be a region that expresses the heme oxygenase enzyme (HO), which catalyzes the metabolism of heme to carbon monoxide (CO). Additionally, several lines of evidence have suggested that the LC can be involved in the modulation of emotional states such as fear and anxiety. The purpose of this investigation was to evaluate the activation of the heme oxygenase-carbon monoxide pathway in the LC in the modulation of anxiety by using the elevated plus maze test (EPM) and light-dark box test (LDB) in rats. Experiments were performed on adult male Wistar rats weighing 250-300 g (n=182). The results showed that the intra-LC microinjection of heme-lysinate (600 nmol), a substrate for the enzyme HO, increased the number of entries into the open arms and the percentage of time spent in open arms in the elevated plus maze test, indicating a decrease in anxiety. Additionally, in the LDB test, intra-LC administration of heme-lysinate promoted an increase on time spent in the light compartment of the box. The intracerebroventricular microinjection of guanylate cyclase, an sGC inhibitor followed by the intra-LC microinjection of the heme-lysinate blocked the anxiolytic-like reaction on the EPM test and LDB test. It can therefore be concluded that CO in the LC produced by the HO pathway and acting via cGMP plays an anxiolytic-like role in the LC of rats.

  16. CARBON MONOXIDE: ITS ROLE IN MITOCHONDRIAL PATHWAY OF APOPTOSIS INDUCTION IN JURKAT CANCER CELLS

    Directory of Open Access Journals (Sweden)

    E. G. Starikova

    2012-01-01

    Full Text Available  Abstract. This study demonstrates ability of carbon monoxide to trigger mitochondrial pathway of apoptosis induction of Jurcat cells. We have shown that proapoptotic action of carbon monoxide is coupled to permeabilization of cellular mitochondrial membranes. Imbalance in Bcl-2 family of regulatory proteins may be considered among possible reasons of the membrane pore formation. We have shown downregulated cl-2 and Bcl-xl mRNA expression and decreased levels of antiapoptotic proteins, along wih decreased mRNA expression and increase of Bad proapototic protein level in Jurkat cells following incubation with 50 μm of CORM-2, a carbon monoxide donor.

  17. Combined carbon and hydrogen isotope fractionation investigations for elucidating benzene biodegradation pathways

    NARCIS (Netherlands)

    Fischer, A.; Herklotz, I.; Herrmann, S.; Thullner, M.; Weelink, S.A.B.; Stams, A.J.M.; Richnow, H.H.; Vogt, C.

    2008-01-01

    Recently, combined carbon and hydrogen isotope fractionation investigations have emerged as a powerful tool for the characterization of reaction mechanisms relevant for the removal of organic pollutants. Here, we applied this approach in order to differentiate benzene biodegradation pathways under o

  18. Structure and Mechanism of PhnP, a Phosphodiesterase of the Carbon-Phosphorus Lyase Pathway

    DEFF Research Database (Denmark)

    He, Shu-Mei; Wathier, Matthew; Podzelinska, Kateryna;

    2011-01-01

    PhnP is a phosphodiesterase that plays an important role within the bacterial carbon-phosphorus lyase (CP-lyase) pathway by recycling a "dead-end" intermediate, 5-phospho-α-d-ribosyl 1,2-cyclic phosphate, that is formed during organophosphonate catabolism. As a member of the metallo-β-lactamase s...

  19. Pathways of carbon assimilation and ammonia oxidation suggested by environmental genomic analyses of marine Crenarchaeota.

    Directory of Open Access Journals (Sweden)

    Steven J Hallam

    2006-04-01

    Full Text Available Marine Crenarchaeota represent an abundant component of oceanic microbiota with potential to significantly influence biogeochemical cycling in marine ecosystems. Prior studies using specific archaeal lipid biomarkers and isotopic analyses indicated that planktonic Crenarchaeota have the capacity for autotrophic growth, and more recent cultivation studies support an ammonia-based chemolithoautotrophic energy metabolism. We report here analysis of fosmid sequences derived from the uncultivated marine crenarchaeote, Cenarchaeum symbiosum, focused on the reconstruction of carbon and energy metabolism. Genes predicted to encode multiple components of a modified 3-hydroxypropionate cycle of autotrophic carbon assimilation were identified, consistent with utilization of carbon dioxide as a carbon source. Additionally, genes predicted to encode a near complete oxidative tricarboxylic acid cycle were also identified, consistent with the consumption of organic carbon and in the production of intermediates for amino acid and cofactor biosynthesis. Therefore, C. symbiosum has the potential to function either as a strict autotroph, or as a mixotroph utilizing both carbon dioxide and organic material as carbon sources. From the standpoint of energy metabolism, genes predicted to encode ammonia monooxygenase subunits, ammonia permease, urease, and urea transporters were identified, consistent with the use of reduced nitrogen compounds as energy sources fueling autotrophic metabolism. Homologues of these genes, recovered from ocean waters worldwide, demonstrate the conservation and ubiquity of crenarchaeal pathways for carbon assimilation and ammonia oxidation. These findings further substantiate the likely global metabolic importance of Crenarchaeota with respect to key steps in the biogeochemical transformation of carbon and nitrogen in marine ecosystems.

  20. Pathway confirmation and flux analysis of central metabolicpathways in Desulfovibrio vulgaris Hildenborough using GasChromatography-Mass Spectrometry and Fourier Transform-Ion CyclotronResonance Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Yinjie; Pingitore, Francesco; Mukhopadhyay, Aindrila; Phan,Richard; Hazen, Terry C.; Keasling, Jay D.

    2007-03-15

    Flux distribution in central metabolic pathways ofDesulfovibrio vulgaris Hildenborough was examined using 13C tracerexperiments. Consistent with the current genome annotation andindependent evidence from enzyme activity assays, the isotopomer resultsfrom both GC-MS and Fourier Transform-Ion Cyclotron Resonance massspectrometry (FT-ICR MS) indicate the lack of oxidatively functional TCAcycle and an incomplete pentose phosphate pathway. Results from thisstudy suggest that fluxes through both pathways are limited tobiosynthesis. The data also indicate that>80 percent of the lactatewas converted to acetate and the reactions involved are the primary routeof energy production (NAD(P)H and ATP production). Independent of the TCAcycle, direct cleavage of acetyl-CoA to CO and 5,10-methyl-THF also leadsto production of NADH and ATP. Although the genome annotation implicatesa ferredoxin-dependentoxoglutarate synthase, isotopic evidence does notsupport flux through this reaction in either the oxidative or reductivemode; therefore, the TCA cycle is incomplete. FT-ICR MS was used tolocate the labeled carbon distribution in aspartate and glutamate andconfirmed the presence of an atypical enzyme for citrate formationsuggested in previous reports (the citrate synthesized by this enzyme isthe isotopic antipode of the citrate synthesized by the (S)-citratesynthase). These findings enable a better understanding of the relationbetween genome annotation and actual metabolic pathways in D. vulgaris,and also demonstrate FT-ICR MS as a powerful tool for isotopomeranalysis, overcoming problems in both GC-MS and NMRspectroscopy.

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

    Science.gov (United States)

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

    2014-02-17

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

  2. 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. PMID:23840455

  3. Distinct mechanisms for spiro-carbon formation reveal biosynthetic pathway crosstalk.

    Science.gov (United States)

    Tsunematsu, Yuta; Ishikawa, Noriyasu; Wakana, Daigo; Goda, Yukihiro; Noguchi, Hiroshi; Moriya, Hisao; Hotta, Kinya; Watanabe, Kenji

    2013-12-01

    Spirotryprostatins, an indole alkaloid class of nonribosomal peptides isolated from Aspergillus fumigatus, are known for their antimitotic activity in tumor cells. Because spirotryprostatins and many other chemically complex spiro-carbon-bearing natural products exhibit useful biological activities, identifying and understanding the mechanism of spiro-carbon biosynthesis is of great interest. Here we report a detailed study of spiro-ring formation in spirotryprostatins from tryprostatins derived from the fumitremorgin biosynthetic pathway, using reactants and products prepared with engineered yeast and fungal strains. Unexpectedly, FqzB, an FAD-dependent monooxygenase from the unrelated fumiquinazoline biosynthetic pathway, catalyzed spiro-carbon formation in spirotryprostatin A via an epoxidation route. Furthermore, FtmG, a cytochrome P450 from the fumitremorgin biosynthetic pathway, was determined to catalyze the spiro-ring formation in spirotryprostatin B. Our results highlight the versatile role of oxygenating enzymes in the biosynthesis of structurally complex natural products and indicate that cross-talk of different biosynthetic pathways allows product diversification in natural product biosynthesis.

  4. Distinct mechanisms for spiro-carbon formation reveal biosynthetic pathway crosstalk.

    Science.gov (United States)

    Tsunematsu, Yuta; Ishikawa, Noriyasu; Wakana, Daigo; Goda, Yukihiro; Noguchi, Hiroshi; Moriya, Hisao; Hotta, Kinya; Watanabe, Kenji

    2013-12-01

    Spirotryprostatins, an indole alkaloid class of nonribosomal peptides isolated from Aspergillus fumigatus, are known for their antimitotic activity in tumor cells. Because spirotryprostatins and many other chemically complex spiro-carbon-bearing natural products exhibit useful biological activities, identifying and understanding the mechanism of spiro-carbon biosynthesis is of great interest. Here we report a detailed study of spiro-ring formation in spirotryprostatins from tryprostatins derived from the fumitremorgin biosynthetic pathway, using reactants and products prepared with engineered yeast and fungal strains. Unexpectedly, FqzB, an FAD-dependent monooxygenase from the unrelated fumiquinazoline biosynthetic pathway, catalyzed spiro-carbon formation in spirotryprostatin A via an epoxidation route. Furthermore, FtmG, a cytochrome P450 from the fumitremorgin biosynthetic pathway, was determined to catalyze the spiro-ring formation in spirotryprostatin B. Our results highlight the versatile role of oxygenating enzymes in the biosynthesis of structurally complex natural products and indicate that cross-talk of different biosynthetic pathways allows product diversification in natural product biosynthesis. PMID:24121553

  5. Reversal of Cytosolic One-Carbon Flux Compensates for Loss of the Mitochondrial Folate Pathway.

    Science.gov (United States)

    Ducker, Gregory S; Chen, Li; Morscher, Raphael J; Ghergurovich, Jonathan M; Esposito, Mark; Teng, Xin; Kang, Yibin; Rabinowitz, Joshua D

    2016-06-14

    One-carbon (1C) units for purine and thymidine synthesis can be generated from serine by cytosolic or mitochondrial folate metabolism. The mitochondrial 1C pathway is consistently overexpressed in cancer. Here, we show that most but not all proliferating mammalian cell lines use the mitochondrial pathway as the default for making 1C units. Clustered regularly interspaced short palindromic repeats (CRISPR)-mediated mitochondrial pathway knockout activates cytosolic 1C-unit production. This reversal in cytosolic flux is triggered by depletion of a single metabolite, 10-formyl-tetrahydrofolate (10-formyl-THF), and enables rapid cell growth in nutrient-replete conditions. Loss of the mitochondrial pathway, however, renders cells dependent on extracellular serine to make 1C units and on extracellular glycine to make glutathione. HCT-116 colon cancer xenografts lacking mitochondrial 1C pathway activity generate the 1C units required for growth by cytosolic serine catabolism. Loss of both pathways precludes xenograft formation. Thus, either mitochondrial or cytosolic 1C metabolism can support tumorigenesis, with the mitochondrial pathway required in nutrient-poor conditions. PMID:27211901

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

    Science.gov (United States)

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

    2014-05-01

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

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

    CERN Document Server

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

    2013-01-01

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

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

    NARCIS (Netherlands)

    Batjes, N.H.

    2002-01-01

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

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

    NARCIS (Netherlands)

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

    2014-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Jiménez-Zurdo José I

    2010-03-01

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

  11. Carbon black and titanium dioxide nanoparticles elicit distinct apoptotic pathways in bronchial epithelial cells

    OpenAIRE

    Baeza-Squiban Armelle; Fleury Jocelyne; Martens Johan A; Andreau Karine; Borot Marie-Caroline; Ferecatu Ioana; Thomassen Leen CJ; Hussain Salik; Marano Francelyne; Boland Sonja

    2010-01-01

    Abstract Background Increasing environmental and occupational exposures to nanoparticles (NPs) warrant deeper insight into the toxicological mechanisms induced by these materials. The present study was designed to characterize the cell death induced by carbon black (CB) and titanium dioxide (TiO2) NPs in bronchial epithelial cells (16HBE14o- cell line and primary cells) and to investigate the implicated molecular pathways. Results Detailed time course studies revealed that both CB (13 nm) and...

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

    DEFF Research Database (Denmark)

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

    2001-01-01

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

  13. Pathway confirmation and flux analysis of central metabolicpathways in Desulfovibrio vulgaris Hildenborough using gaschromatography-mass spectrometry and fourier transform-ion cyclotronresonance mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Yinjie; Pingitore, Francesco; Mukhopadhyay, Aindrila; Phan,Richard; Hazen, Terry C.; Keasling, Jay D.

    2006-07-11

    It has been proposed that during growth under anaerobic oroxygen-limited conditions Shewanella oneidensis MR-1 uses theserine-isocitrate lyase pathway common to many methylotrophic anaerobes,in which formaldehyde produced from pyruvate is condensed with glycine toform serine. The serine is then transformed through hydroxypyruvate andglycerate to enter central metabolism at phosphoglycerate. To examine itsuse of the serine-isocitrate lyase pathway under anaerobic conditions, wegrew S. oneidensis MR-1 on [1-13C]lactate as the sole carbon source witheither trimethylamine N-oxide (TMAO) or fumarate as an electron acceptor.Analysis of cellular metabolites indicates that a large percentage(>75 percent) of lactate was partially oxidized to either acetate orpyruvate. The 13C isotope distributions in amino acids and other keymetabolites indicate that, under anaerobic conditions, a complete serinepathway is not present, and lactate is oxidized via a highly reversibleserine degradation pathway. The labeling data also suggest significantactivity in the anaplerotic (malic enzyme and phosphoenolpyruvatecarboxylase) and glyoxylate shunt (isocitrate lyase and malate synthase)reactions. Although the tricarboxylic acid (TCA) cycle is often observedto be incomplete in many other anaerobes (absence of 2-oxoglutaratedehydrogenase activity), isotopic labeling supports the existence of acomplete TCA cycle in S. oneidensis MR-1 under TMAO reductioncondition.

  14. Differences in the dynamic baroreflex characteristics of unmyelinated and myelinated central pathways are less evident in spontaneously hypertensive rats.

    Science.gov (United States)

    Turner, Michael J; Kawada, Toru; Shimizu, Shuji; Fukumitsu, Masafumi; Sugimachi, Masaru

    2015-12-01

    The aim of the study was to identify the contribution of myelinated (A-fiber) and unmyelinated (C-fiber) baroreceptor central pathways to the baroreflex control of sympathetic nerve activity (SNA) and arterial pressure (AP) in anesthetized Wistar-Kyoto (WKY; n = 8) and spontaneously hypertensive rats (SHR; n = 8). The left aortic depressor nerve (ADN) was electrically stimulated with two types of binary white noise signals designed to preferentially activate A-fibers (A-BRx protocol) or C-fibers (C-BRx protocol). In WKY, the central arc transfer function from ADN stimulation to SNA estimated by A-BRx showed strong derivative characteristics with the slope of dynamic gain between 0.1 and 1 Hz (Gslope) of 14.63 ± 0.89 dB/decade. In contrast, the central arc transfer function estimated by C-BRx exhibited nonderivative characteristics with Gslope of 0.64 ± 1.13 dB/decade. This indicates that A-fibers are important for rapid baroreflex regulation, whereas C-fibers are likely important for more sustained regulation of SNA and AP. In SHR, the central arc transfer function estimated by A-BRx showed higher Gslope (18.46 ± 0.75 dB/decade, P < 0.01) and that estimated by C-BRx showed higher Gslope (8.62 ± 0.64 dB/decade, P < 0.001) with significantly lower dynamic gain at 0.01 Hz (6.29 ± 0.48 vs. 2.80 ± 0.36%/Hz, P < 0.001) compared with WKY. In conclusion, the dynamic characteristics of the A-fiber central pathway are enhanced in the high-modulation frequency range (0.1-1 Hz) and those of the C-fiber central pathway are attenuated in the low-modulation frequency range (0.01-0.1 Hz) in SHR. PMID:26377561

  15. Potential role of multiple carbon fixation pathways during lipid accumulation in Phaeodactylum tricornutum

    Directory of Open Access Journals (Sweden)

    Valenzuela Jacob

    2012-06-01

    Full Text Available Abstract Background Phaeodactylum tricornutum is a unicellular diatom in the class Bacillariophyceae. The full genome has been sequenced (P. tricornutum gene expression profiles during nutrient-deprivation and lipid-accumulation, cell cultures were grown with a nitrate to phosphate ratio of 20:1 (N:P and whole-genome transcripts were monitored over time via RNA-sequence determination. Results The specific Nile Red (NR fluorescence (NR fluorescence per cell increased over time; however, the increase in NR fluorescence was initiated before external nitrate was completely exhausted. Exogenous phosphate was depleted before nitrate, and these results indicated that the depletion of exogenous phosphate might be an early trigger for lipid accumulation that is magnified upon nitrate depletion. As expected, many of the genes associated with nitrate and phosphate utilization were up-expressed. The diatom-specific cyclins cyc7 and cyc10 were down-expressed during the nutrient-deplete state, and cyclin B1 was up-expressed during lipid-accumulation after growth cessation. While many of the genes associated with the C3 pathway for photosynthetic carbon reduction were not significantly altered, genes involved in a putative C4 pathway for photosynthetic carbon assimilation were up-expressed as the cells depleted nitrate, phosphate, and exogenous dissolved inorganic carbon (DIC levels. P. tricornutum has multiple, putative carbonic anhydrases, but only two were significantly up-expressed (2-fold and 4-fold at the last time point when exogenous DIC levels had increased after the cessation of growth. Alternative pathways that could utilize HCO3- were also suggested by the gene expression profiles (e.g., putative propionyl-CoA and methylmalonyl-CoA decarboxylases. Conclusions The results indicate that P. tricornutum continued carbon dioxide reduction when population growth was arrested and different carbon-concentrating mechanisms were used dependent upon exogenous

  16. Carbon and hydrogen isotopic composition and generation pathway of biogenic gas in China

    Institute of Scientific and Technical Information of China (English)

    SHEN Ping; WANG Xiaofeng; XU Yin; SHI Baoguang; XU Yongchang

    2009-01-01

    The carbon and hydrogen isotopic composition of biogenic gas is of great importance for the study of its generation pathway and reservoiring characteristics. In this paper, the formation pathways and reservoiring characteristics of biogenic gas reservoirs in China are described in terms of the carbon and hydrogen isotopic compositions of 31 gas samples from 10 biogenic gas reservoirs. The study shows that the hydrogen isotopic compositions of these biogenic gas reservoirs can be divided into three intervals:δDCH4>-200‰,-250‰<δDCH4<-200‰ and δDCH4<-250‰. The forerunners believed that the main generation pathway of biogenic gas under the condition of continental fresh water is acetic fermentation. Our research results showed that the generation pathway of biogenic gas under the condition of marine facies is typical CO2- reduction, the biogenic gas has heavy hydrogen isotopic composition: its δDCH4 values are higher than -200‰; that the biogenic gas under the condition of continental facies also was generated by the same way, but its hydrogen isotopic composition is lighter than that of biogenetic gas generated under typical marine facies condition: -250‰<δDCH4<-200‰, the δDCH4 values may be related to the salinity of the water medium in ancient lakes. From the relevant data of the Qaidam Basin, it can be seen that the hydrogen isotopic composition of biogenic methane has the same variation trend with increasing salinity of water medium. There are biogenic gas reservoirs formed in transitional regions under the condition of continental facies. These gas reservoirs resulted from both CO2- reduction and acetic fermentation, the formation of which may be related to the non-variant salinity of ancient water medium and the relatively high geothermal gradient, as is the case encountered in the Baoshan Basin. The biogenic gas generating in these regions has light hydrogen isotopic composition: δDCH4<-250‰, and relatively heavy carbon isotopic

  17. BMP and TGFbeta pathways in human central chondrosarcoma: enhanced endoglin and Smad 1 signaling in high grade tumors

    International Nuclear Information System (INIS)

    As major regulators of normal chondrogenesis, the bone morphogenic protein (BMP) and transforming growth factor β (TGFB) signaling pathways may be involved in the development and progression of central chondrosarcoma. In order to uncover their possible implication, the aim of this study was to perform a systematic quantitative study of the expression of BMPs, TGFBs and their receptors and to assess activity of the corresponding pathways in central chondrosarcoma. Gene expression analysis was performed by quantitative RT-PCR in 26 central chondrosarcoma and 6 healthy articular cartilage samples. Expression of endoglin and nuclear localization of phosphorylated Smad1/5/8 and Smad2 was assessed by immunohistochemical analysis. The expression of TGFB3 and of the activin receptor-like kinase ALK2 was found to be significantly higher in grade III compared to grade I chondrosarcoma. Nuclear phosphorylated Smad1/5/8 and Smad2 were found in all tumors analyzed and the activity of both signaling pathways was confirmed by functional reporter assays in 2 chondrosarcoma cell lines. Immunohistochemical analysis furthermore revealed that phosphorylated Smad1/5/8 and endoglin expression were significantly higher in high-grade compared to low-grade chondrosarcoma and correlated to each other. The BMP and TGFβ signaling pathways were found to be active in central chondrosarcoma cells. The correlation of Smad1/5/8 activity to endoglin expression suggests that, as described in other cell types, endoglin could enhance Smad1/5/8 signaling in high-grade chondrosarcoma cells. Endoglin expression coupled to Smad1/5/8 activation could thus represent a functionally important signaling axis for the progression of chondrosarcoma and a regulator of the undifferentiated phenotype of high-grade tumor cells

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

    Institute of Scientific and Technical Information of China (English)

    黎廷宇; 王世杰; 郑乐平

    2002-01-01

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

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

    Science.gov (United States)

    Wagner, Christiane; Deloule, Etienne

    2016-04-01

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

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

    OpenAIRE

    Nanda Nautiyal; Vir Singh

    2013-01-01

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

  1. Scenario analysis of China's emissions pathways in the 21st century for low carbon transition

    International Nuclear Information System (INIS)

    China's growing demand for energy - and its dependence on coal - has seen its carbon emissions increase more than 50% since 2000. Within the debate about mitigating global climate change, there is mounting pressure for emerging economies like China to take more responsibility for reducing their carbon emissions within a post-2012 international climate change policy framework. For China, this leads to fundamental questions about how feasible it is for the country to shift away from its recent carbon intensive pattern of growth. This paper presents some general results of scenarios that have been developed to investigate how China might continue to develop within a cumulative carbon emissions budget. The results show how changes in the key sectors of the Chinese economy could enable China to follow four different low carbon development pathways, each of which complies with a cumulative emissions constraint. Each scenario reflects different priorities for governmental decision making, infrastructure investments and social preferences. Having compared the key features of each scenario, the paper concludes with some implications for Chinese government policy.

  2. Scenario analysis of China's emissions pathways in the 21st century for low carbon transition

    International Nuclear Information System (INIS)

    China's growing demand for energy - and its dependence on coal - has seen its carbon emissions increase more than 50% since 2000. Within the debate about mitigating global climate change, there is mounting pressure for emerging economies like China to take more responsibility for reducing their carbon emissions within a post-2012 international climate change policy framework. For China, this leads to fundamental questions about how feasible it is for the country to shift away from its recent carbon intensive pattern of growth. This paper presents some general results of scenarios that have been developed to investigate how China might continue to develop within a cumulative carbon emissions budget. The results show how changes in the key sectors of the Chinese economy could enable China to follow four different low carbon development pathways, each of which complies with a cumulative emissions constraint. Each scenario reflects different priorities for governmental decision making, infrastructure investments and social preferences. Having compared the key features of each scenario, the paper concludes with some implications for Chinese government policy. (author)

  3. The biochemical pathways of central nervous system neural degeneration in niacin deifciency

    Institute of Scientific and Technical Information of China (English)

    Linshan Fu; Venkatesh Doreswamy; Ravi Prakash

    2014-01-01

    Neural degeneration is a very complicated process. In spite of all the advancements in the mo-lecular chemistry, there are many unknown aspects of the phenomena of neurodegeneration which need to be put together. It is a common sequela of the conditions of niacin deifciency. Neural degeneration in Pellagra manifests as chromatolysis mainly in pyramidal followed by other neurons and glial cells. However, there is a gross lack of understanding of biochemi-cal mechanisms of neurodegeneration in niacin deifciency states. Because of the necessity of niacin or its amide derivative NAD in a number of biochemical pathways, it is understandable that several of these pathways may be involved in the common outcome of neural degener-ation. Here, we highlight ifve pathways that could be involved in the neuraldegeneration for which evidence has accumulated through several studies. These pathways are:1) the trypto-phan-kyneurenic acid pathway, 2) the mitochondrial ATP generation related pathways, 3) the poly (ADP-ibose) polymerase (PARP) pathway, 4) the BDNF-TRKB Axis abnormalities, 5) the genetic inlfuences of niacin deifciency.

  4. Secondary brown carbon formation via the dicarbonyl imine pathway: nitrogen heterocycle formation and synergistic effects.

    Science.gov (United States)

    Kampf, C J; Filippi, A; Zuth, C; Hoffmann, T; Opatz, T

    2016-07-21

    Dicarbonyls are known to be important precursors of so-called atmospheric brown carbon, significantly affecting aerosol optical properties and radiative forcing. In this systematic study we report the formation of light-absorbing nitrogen containing compounds from simple 1,2-, 1,3-, 1,4-, and 1,5-dicarbonyl + amine reactions. A combination of spectrophotometric and mass spectrometric techniques was used to characterize reaction products in solutions mimicking atmospheric particulates. Experiments with individual dicarbonyls and dicarbonyl mixtures in ammonium sulfate and glycine solutions demonstrate that nitrogen heterocycles are common structural motifs of brown carbon chromophores formed in such reaction systems. 1,4- and 1,5-dicarbonyl reaction systems, which were used as surrogates for terpene ozonolysis products, showed rapid formation of light-absorbing material and products with absorbance maxima at ∼450 nm. Synergistic effects on absorbance properties were observed in mixed (di-)carbonyl experiments, as indicated by the formation of a strong absorber in ammonium sulfate solutions containing acetaldehyde and acetylacetone. This cross-reaction oligomer shows an absorbance maximum at 385 nm, relevant for the actinic flux region of the atmosphere. This study demonstrates the complexity of secondary brown carbon formation via the imine pathway and highlights that cross-reactions with synergistic effects have to be considered an important pathway for atmospheric BrC formation. PMID:27334793

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

    Institute of Scientific and Technical Information of China (English)

    黎廷宇; 王世杰; 郑乐平

    2002-01-01

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

  6. Evaluating reaction pathways of hydrothermal abiotic organic synthesis at elevated temperatures and pressures using carbon isotopes

    Science.gov (United States)

    Fu, Qi; Socki, Richard A.; Niles, Paul B.

    2015-04-01

    Experiments were performed to better understand the role of environmental factors on reaction pathways and corresponding carbon isotope fractionations during abiotic hydrothermal synthesis of organic compounds using piston cylinder apparatus at 750 °C and 5.5 kbars. Chemical compositions of experimental products and corresponding carbon isotopic values were obtained by a Pyrolysis-GC-MS-IRMS system. Alkanes (methane and ethane), straight-chain saturated alcohols (ethanol and n-butanol) and monocarboxylic acids (formic and acetic acids) were generated with ethanol being the only organic compound with higher δ13C than CO2. CO was not detected in experimental products owing to the favorable water-gas shift reaction under high water pressure conditions. The pattern of δ13C values of CO2, carboxylic acids and alkanes are consistent with their equilibrium isotope relationships: CO2 > carboxylic acids > alkanes, but the magnitude of the fractionation among them is higher than predicted isotope equilibrium values. In particular, the isotopic fractionation between CO2 and CH4 remained constant at ∼31‰, indicating a kinetic effect during CO2 reduction processes. No "isotope reversal" of δ13C values for alkanes or carboxylic acids was observed, which indicates a different reaction pathway than what is typically observed during Fischer-Tropsch synthesis under gas phase conditions. Under constraints imposed in experiments, the anomalous 13C isotope enrichment in ethanol suggests that hydroxymethylene is the organic intermediate, and that the generation of other organic compounds enriched in 12C were facilitated by subsequent Rayleigh fractionation of hydroxymethylene reacting with H2 and/or H2O. Carbon isotope fractionation data obtained in this study are instrumental in assessing the controlling factors on abiotic formation of organic compounds in hydrothermal systems. Knowledge on how environmental conditions affect reaction pathways of abiotic synthesis of organic

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1992-01-01

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

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

    Science.gov (United States)

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

    2016-08-01

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

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

    Directory of Open Access Journals (Sweden)

    Vlčková Jana

    2015-12-01

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

  10. Brain potentials evoked by intraepidermal electrical stimuli reflect the central sensitization of nociceptive pathways

    OpenAIRE

    Liang, M.; Lee, M. C.; O'Neill, J.; Dickenson, A.H.; Iannetti, G.D.

    2016-01-01

    Central sensitization (CS), the increased sensitivity of the central nervous system to somatosensory inputs, accounts for secondary hyperalgesia, a typical sign of several painful clinical conditions. Brain potentials elicited by mechanical punctate stimulation using flat-tip probes can provide neural correlates of CS, but their signal-to-noise ratio is limited by poor synchronisation of the afferent nociceptive input. Additionally, mechanical punctate stimulation does not activate nociceptor...

  11. Conversion of 4-Hydroxybutyrate to Acetyl Coenzyme A and Its Anapleurosis in the Metallosphaera sedula 3-Hydroxypropionate/4-Hydroxybutyrate Carbon Fixation Pathway

    Energy Technology Data Exchange (ETDEWEB)

    Hawkins, AB; Adams, MWW; Kelly, RM

    2014-03-25

    The extremely thermoacidophilic archaeon Metallosphaera sedula (optimum growth temperature, 73 degrees C, pH 2.0) grows chemolithoautotrophically on metal sulfides or molecular hydrogen by employing the 3-hydroxypropionate/4-hydroxybutyrate (3HP/4HB) carbon fixation cycle. This cycle adds two CO2 molecules to acetyl coenzyme A (acetyl-CoA) to generate 4HB, which is then rearranged and cleaved to form two acetyl-CoA molecules. Previous metabolic flux analysis showed that two-thirds of central carbon precursor molecules are derived from succinyl-CoA, which is oxidized to malate and oxaloacetate. The remaining one-third is apparently derived from acetyl-CoA. As such, the steps beyond succinyl-CoA are essential for completing the carbon fixation cycle and for anapleurosis of acetyl-CoA. Here, the final four enzymes of the 3HP/4HB cycle, 4-hydroxybutyrate-CoA ligase (AMP forming) (Msed_0406), 4-hydroxybutyryl-CoA dehydratase (Msed_1321), crotonyl-CoA hydratase/(S)-3-hydroxybutyryl-CoA dehydrogenase (Msed_0399), and acetoacetyl-CoA beta-ketothiolase (Msed_0656), were produced recombinantly in Escherichia coli, combined in vitro, and shown to convert 4HB to acetyl-CoA. Metabolic pathways connecting CO2 fixation and central metabolism were examined using a gas-intensive bioreactor system in which M. sedula was grown under autotrophic (CO2-limited) and heterotrophic conditions. Transcriptomic analysis revealed the importance of the 3HP/4HB pathway in supplying acetyl-CoA to anabolic pathways generating intermediates in M. sedula metabolism. The results indicated that flux between the succinate and acetyl-CoA branches in the 3HP/4HB pathway is governed by 4-hydroxybutyrate-CoA ligase, possibly regulated posttranslationally by the protein acetyltransferase (Pat)/Sir2-dependent system. Taken together, this work confirms the final four steps of the 3HP/4HB pathway, thereby providing the framework for examining connections between CO2 fixation and central metabolism in M. sedula.

  12. Evidence and future scenarios of a low-carbon energy transition in Central America: a case study in Nicaragua

    Science.gov (United States)

    Barido, Diego Ponce de Leon; Johnston, Josiah; Moncada, Maria V.; Callaway, Duncan; Kammen, Daniel M.

    2015-10-01

    The global carbon emissions budget over the next decades depends critically on the choices made by fast-growing emerging economies. Few studies exist, however, that develop country-specific energy system integration insights that can inform emerging economies in this decision-making process. High spatial- and temporal-resolution power system planning is central to evaluating decarbonization scenarios, but obtaining the required data and models can be cost prohibitive, especially for researchers in low, lower-middle income economies. Here, we use Nicaragua as a case study to highlight the importance of high-resolution open access data and modeling platforms to evaluate fuel-switching strategies and their resulting cost of power under realistic technology, policy, and cost scenarios (2014-2030). Our results suggest that Nicaragua could cost-effectively achieve a low-carbon grid (≥80%, based on non-large hydro renewable energy generation) by 2030 while also pursuing multiple development objectives. Regional cooperation (balancing) enables the highest wind and solar generation (18% and 3% by 2030, respectively), at the least cost (US127 MWh-1). Potentially risky resources (geothermal and hydropower) raise system costs but do not significantly hinder decarbonization. Oil price sensitivity scenarios suggest renewable energy to be a more cost-effective long-term investment than fuel oil, even under the assumption of prevailing cheap oil prices. Nicaragua’s options illustrate the opportunities and challenges of power system decarbonization for emerging economies, and the key role that open access data and modeling platforms can play in helping develop low-carbon transition pathways.

  13. Centralized modularity of N-linked glycosylation pathways in mammalian cells.

    Directory of Open Access Journals (Sweden)

    Pan-Jun Kim

    Full Text Available Glycosylation is a highly complex process to produce a diverse repertoire of cellular glycans that are attached to proteins and lipids. Glycans are involved in fundamental biological processes, including protein folding and clearance, cell proliferation and apoptosis, development, immune responses, and pathogenesis. One of the major types of glycans, N-linked glycans, is formed by sequential attachments of monosaccharides to proteins by a limited number of enzymes. Many of these enzymes can accept multiple N-linked glycans as substrates, thereby generating a large number of glycan intermediates and their intermingled pathways. Motivated by the quantitative methods developed in complex network research, we investigated the large-scale organization of such N-linked glycosylation pathways in mammalian cells. The N-linked glycosylation pathways are extremely modular, and are composed of cohesive topological modules that directly branch from a common upstream pathway of glycan synthesis. This unique structural property allows the glycan production between modules to be controlled by the upstream region. Although the enzymes act on multiple glycan substrates, indicating cross-talk between modules, the impact of the cross-talk on the module-specific enhancement of glycan synthesis may be confined within a moderate range by transcription-level control. The findings of the present study provide experimentally-testable predictions for glycosylation processes, and may be applicable to therapeutic glycoprotein engineering.

  14. Kenya's Climate Change Action Plan. Low Carbon Climate Resilient Development Pathway

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, D.; Sawyer, D.; Stiebert, S.; McFatridge, S. [International Institute for Sustainable Development IISD, Winnipeg, Manitoba (Canada); Wuertenberger, L.; Van Tilburg, X.; Hekkenberg, M. [Energy research Centre of the Netherlands ECN, Policy Studies, Amsterdam (Netherlands); Owino, T.; Battye, W. [ClimateCare, Nairobi (Kenya); Mutia, T. [Regional Institute for Social Enterprise Kenya RISE, Nairobi (Kenya); Olum, P. [Climate Change Consultant (Kenya)

    2012-12-15

    Kenya Vision 2030 - the long-term development blueprint for the country - aims to transform Kenya into 'a newly industrialising, middle-income country providing a high quality of life to all its citizens in a clean and secure environment'. A low carbon climate resilient development pathway, as set out in this Climate Change Action Plan, can help meet Vision 2030 goals through actions that address both sustainable development and climate change. This pathway can also help the Government achieve the Millennium Development Goals and other internationally agreed development goals without compromising the environment and its natural resources. As Kenya realizes its development aspirations, there will be gains and risks. A growing population and economy with migration to cities will mean increases in greenhouse gas (GHG) emissions. Resulting environmental and social conditions, including increased competition over resources, could intensify vulnerability to climate risks. Transitioning to a low carbon climate resilient development pathway can address future risks thereby improving Kenya's ability to prosper under a changing climate while reducing the emissions intensity of a growing economy. Moving forward on the 2010 National Climate Change Response Strategy will help Kenya transition to a low carbon climate resilient development pathway that puts people and livelihoods at the forefront. The strategy recognized the importance of climate change and development, and this Climate Change Action Plan is the logical next step. A yearlong multistakeholder participatory process involving the public sector, private sector and civil society resulted in this Action Plan that identifies priority climate change actions for Kenya for the short, medium and long term. The Government of Kenya takes climate change and its impact on development seriously. Climate change is considered a crosscutting issue that will be mainstreamed in the planning process both at the national

  15. Air-ice carbon pathways inferred from a sea ice tank experiment

    Directory of Open Access Journals (Sweden)

    Marie Kotovitch

    2016-06-01

    Full Text Available Abstract Given rapid sea ice changes in the Arctic Ocean in the context of climate warming, better constraints on the role of sea ice in CO2 cycling are needed to assess the capacity of polar oceans to buffer the rise of atmospheric CO2 concentration. Air-ice CO2 fluxes were measured continuously using automated chambers from the initial freezing of a sea ice cover until its decay during the INTERICE V experiment at the Hamburg Ship Model Basin. Cooling seawater prior to sea ice formation acted as a sink for atmospheric CO2, but as soon as the first ice crystals started to form, sea ice turned to a source of CO2, which lasted throughout the whole ice growth phase. Once ice decay was initiated by warming the atmosphere, the sea ice shifted back again to a sink of CO2. Direct measurements of outward ice-atmosphere CO2 fluxes were consistent with the depletion of dissolved inorganic carbon in the upper half of sea ice. Combining measured air-ice CO2 fluxes with the partial pressure of CO2 in sea ice, we determined strongly different gas transfer coefficients of CO2 at the air-ice interface between the growth and the decay phases (from 2.5 to 0.4 mol m−2 d−1 atm−1. A 1D sea ice carbon cycle model including gas physics and carbon biogeochemistry was used in various configurations in order to interpret the observations. All model simulations correctly predicted the sign of the air-ice flux. By contrast, the amplitude of the flux was much more variable between the different simulations. In none of the simulations was the dissolved gas pathway strong enough to explain the large fluxes during ice growth. This pathway weakness is due to an intrinsic limitation of ice-air fluxes of dissolved CO2 by the slow transport of dissolved inorganic carbon in the ice. The best means we found to explain the high air-ice carbon fluxes during ice growth is an intense yet uncertain gas bubble efflux, requiring sufficient bubble nucleation and upwards rise. We

  16. New Pathways and Metrics for Enhanced, Reversible Hydrogen Storage in Boron-Doped Carbon Nanospaces

    Energy Technology Data Exchange (ETDEWEB)

    Pfeifer, Peter [University of Missouri; Wexler, Carlos [University of Missouri; Hawthorne, M. Frederick [University of Missouri; Lee, Mark W. [University of Missouri; Jalistegi, Satish S. [University of Missouri

    2014-08-14

    This project, since its start in 2007—entitled “Networks of boron-doped carbon nanopores for low-pressure reversible hydrogen storage” (2007-10) and “New pathways and metrics for enhanced, reversible hydrogen storage in boron-doped carbon nanospaces” (2010-13)—is in support of the DOE's National Hydrogen Storage Project, as part of the DOE Hydrogen and Fuel Cells Program’s comprehensive efforts to enable the widespread commercialization of hydrogen and fuel cell technologies in diverse sectors of the economy. Hydrogen storage is widely recognized as a critical enabling technology for the successful commercialization and market acceptance of hydrogen powered vehicles. Storing sufficient hydrogen on board a wide range of vehicle platforms, at energy densities comparable to gasoline, without compromising passenger or cargo space, remains an outstanding technical challenge. Of the main three thrust areas in 2007—metal hydrides, chemical hydrogen storage, and sorption-based hydrogen storage—sorption-based storage, i.e., storage of molecular hydrogen by adsorption on high-surface-area materials (carbons, metal-organic frameworks, and other porous organic networks), has emerged as the most promising path toward achieving the 2017 DOE storage targets of 0.055 kg H2/kg system (“5.5 wt%”) and 0.040 kg H2/liter system. The objective of the project is to develop high-surface-area carbon materials that are boron-doped by incorporation of boron into the carbon lattice at the outset, i.e., during the synthesis of the material. The rationale for boron-doping is the prediction that boron atoms in carbon will raise the binding energy of hydro- gen from 4-5 kJ/mol on the undoped surface to 10-14 kJ/mol on a doped surface, and accordingly the hydro- gen storage capacity of the material. The mechanism for the increase in binding energy is electron donation from H2 to electron-deficient B atoms, in the form of sp2 boron-carbon bonds. Our team is proud to have

  17. MPTP’s Pathway of Toxicity Indicates Central Role of Transcription Factor SP1

    OpenAIRE

    Maertens, Alexandra; Luechtefeld, Thomas; KLEENSANG Andre; Hartung, Thomas

    2015-01-01

    Deriving a Pathway of Toxicity from transcriptomic data remains a challenging task. We explore the use of weighted gene correlation network analysis (WGCNA) to extract an initial network from a small microarray study of MPTP toxicity in mice. Five modules were statistically significant; each module was analyzed for gene signatures in the Chemical and Genetic Perturbation subset of the Molecular Signatures Database as well as for over-represented transcription factor binding sites and WGCNA cl...

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-02-15

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

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

    Science.gov (United States)

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

    2015-04-01

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

  1. 13C-metabolic flux ratio and novel carbon path analyses confirmed that Trichoderma reesei uses primarily the respirative pathway also on the preferred carbon source glucose

    Directory of Open Access Journals (Sweden)

    Saloheimo Markku

    2009-10-01

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

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

    Directory of Open Access Journals (Sweden)

    Nanda Nautiyal

    2013-05-01

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

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

    Science.gov (United States)

    Siudek, Patrycja; Frankowski, Marcin; Siepak, Jerzy

    2015-07-01

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

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

    Science.gov (United States)

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

    2015-12-01

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

  5. Using Phospholipids and Stable Carbon Isotopes to Assess Microbial Community Structures and Carbon Cycle Pathways in Kamchatka Hot Springs

    Science.gov (United States)

    Zhao, W.; Romanek, C. S.; Burgess, E. A.; Wiegel, J.; Mills, G.; Zhang, C. L.

    2006-12-01

    Phospholipid fatty acid (PLFA) and stable carbon isotopes were used to assess the microbial community structures in Kamchatka hot springs. Eighteen mats or surface sediments were collected from hot springs having temperatures of 31 to 91°C and pHs of 4.9 to 8.5. These samples were clearly separated into three groups according to the bacterial PLFA: 1) those dominated by terminally branched odd-numbered fatty acids, 2) those dominated by C18:1 and 3) those dominated by C20:1. With support from other minor PLFA components, group 2 may be used as biomarkers for Chloroflexales or other phototrophic bacteria and group 3 for Aquificales, respectively. Among the sampled hot springs, the Arkashin pool represents the simplest microbial structure with members of Aquificales being the dominant primary producers. On the other hand, the Zavarzin pool may represent the most heterogeneous pool that may include members of Chloroflexales and Aquificales as primary producers. Bacterial 16S rDNA clone libraries confirmed the presence of these microbial groups in the two pools. Results of stable carbon isotope fractionation between CO2 source, bulk biomass and total PLFA showed that primary producers in the Arkashin pool primarily used the reductive tricarboxylic acid (rTCA) cycle (e.g., members of Aquificales); whereas the Zavarzin pool may be a mixture of the 3-hydroxypropionate (3-HP) pathway (e.g. members of Chloroflexales) and the rTCA cycle. Bacterial contribution using the Calvin cycle was not significant and may be less important in Kamchatka hot springs.

  6. Photosynthetic carbon fixation pathways in Zostera marina and three Florida seagrasses

    Energy Technology Data Exchange (ETDEWEB)

    Beer, S.; Wetzel, R.G.

    1982-06-01

    The photosynthetic carbon fixation pathways of four seagrass species, Zostera marina L. from Alaska and Thalassia testudinum Banks ex Konig, Syringodium filiforme Kutz. and Halodule wrightii Aschers. from the Gulf of Mexico, were investigated with a /sup 14/C pulse-chase technique. All species were found to be principally of the C/sub 3/ type. However, Thalassia and Halodule had higher initial incorporation rates into organic acids than is typical for terrestrial C/sub 3/ plants. Of 11 seagrass species investigated thus far for C/sub 3/ or C/sub 4/ metabolism using this technique, 10 were found to be principally of the C/sub 3/ type while only one exhibited C/sub 4/ metabolism.

  7. 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

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-08-17

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

  9. Modulation of apoptotic pathways of macrophages by surface-functionalized multi-walled carbon nanotubes.

    Directory of Open Access Journals (Sweden)

    Yuanqin Jiang

    Full Text Available Biomedical applications of carbon nanotubes (CNTs often involve improving their hydrophilicity and dispersion in biological media by modifying them through noncovalent or covalent functionalization. However, the potential adverse effects of surface-functionalized CNTs have not been well characterized. In this study, we functionalized multi-walled CNTs (MWCNTs via carboxylation, to produce MWCNTs-COOH, and via poly (ethylene glycol linking, to produce MWCNTs-PEG. We used these functionalized MWCNTs to study the effect of surface functionalization on MWCNTs-induced toxicity to macrophages, and elucidate the underlying mechanisms of action. Our results revealed that MWCNTs-PEG were less cytotoxic and were associated with less apoptotic cell death of macrophages than MWCNTs-COOH. Additionally, MWCNTs-PEG induced less generation of reactive oxygen species (ROS involving less activation of NADPH oxidase compared with MWCNTs-COOH, as evidenced by membrane translocation of p47(phox and p67(phox in macrophages. The less cytotoxic and apoptotic effect of MWCNTs-PEG compared with MWCNTs-COOH resulted from the lower cellular uptake of MWCNTs-PEG, which resulted in less activation of oxidative stress-responsive pathways, such as p38 mitogen-activated protein kinases (MAPK and nuclear factor (NF-κB. These results demonstrate that surface functionalization of CNTs may alter ROS-mediated cytotoxic and apoptotic response by modulating apoptotic signaling pathways. Our study thus provides new insights into the molecular basis for the surface properties affecting CNTs toxicity.

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

    Science.gov (United States)

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

    2014-01-01

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

  11. Wnt signaling pathway improves central inhibitory synaptic transmission in a mouse model of Duchenne muscular dystrophy.

    Science.gov (United States)

    Fuenzalida, Marco; Espinoza, Claudia; Pérez, Miguel Ángel; Tapia-Rojas, Cheril; Cuitino, Loreto; Brandan, Enrique; Inestrosa, Nibaldo C

    2016-02-01

    The dystrophin-associated glycoprotein complex (DGC) that connects the cytoskeleton, plasma membrane and the extracellular matrix has been related to the maintenance and stabilization of channels and synaptic receptors, which are both essential for synaptogenesis and synaptic transmission. The dystrophin-deficient (mdx) mouse model of Duchenne muscular dystrophy (DMD) exhibits a significant reduction in hippocampal GABA efficacy, which may underlie the altered synaptic function and abnormal hippocampal long-term plasticity exhibited by mdx mice. Emerging studies have implicated Wnt signaling in the modulation of synaptic efficacy, neuronal plasticity and cognitive function. We report here that the activation of the non-canonical Wnt-5a pathway and Andrographolide, improves hippocampal mdx GABAergic efficacy by increasing the number of inhibitory synapses and GABA(A) receptors or GABA release. These results indicate that Wnt signaling modulates GABA synaptic efficacy and could be a promising novel target for DMD cognitive therapy. PMID:26626079

  12. Carbon black and titanium dioxide nanoparticles elicit distinct apoptotic pathways in bronchial epithelial cells

    Directory of Open Access Journals (Sweden)

    Baeza-Squiban Armelle

    2010-04-01

    Full Text Available Abstract Background Increasing environmental and occupational exposures to nanoparticles (NPs warrant deeper insight into the toxicological mechanisms induced by these materials. The present study was designed to characterize the cell death induced by carbon black (CB and titanium dioxide (TiO2 NPs in bronchial epithelial cells (16HBE14o- cell line and primary cells and to investigate the implicated molecular pathways. Results Detailed time course studies revealed that both CB (13 nm and TiO2(15 nm NP exposed cells exhibit typical morphological (decreased cell size, membrane blebbing, peripheral chromatin condensation, apoptotic body formation and biochemical (caspase activation and DNA fragmentation features of apoptotic cell death. A decrease in mitochondrial membrane potential, activation of Bax and release of cytochrome c from mitochondria were only observed in case of CB NPs whereas lipid peroxidation, lysosomal membrane destabilization and cathepsin B release were observed during the apoptotic process induced by TiO2 NPs. Furthermore, ROS production was observed after exposure to CB and TiO2 but hydrogen peroxide (H2O2 production was only involved in apoptosis induction by CB NPs. Conclusions Both CB and TiO2 NPs induce apoptotic cell death in bronchial epithelial cells. CB NPs induce apoptosis by a ROS dependent mitochondrial pathway whereas TiO2 NPs induce cell death through lysosomal membrane destabilization and lipid peroxidation. Although the final outcome is similar (apoptosis, the molecular pathways activated by NPs differ depending upon the chemical nature of the NPs.

  13. Abused inhalants and central reward pathways: electrophysiological and behavioral studies in the rat.

    Science.gov (United States)

    Riegel, Arthur C; French, Edward D

    2002-06-01

    Inhalant abuse remains a significant health problem among the younger segment of society. In fact, the use of inhalants in this population trails only that of nicotine, alcohol, and marijuana. Toluene is a common ingredient in many of the substances sought out for inhalation abuse, apparently for its euphorigenic and hallucinogenic effects. Because drugs of abuse share the common property of altering the activity of mesolimbic dopamine neurons, it is reasonable to suspect that toluene-induced changes in this CNS pathway may underlie its abuse potential. Here we will provide in vivo and in vitro electrophysiological data and behavioral evidence linking toluene exposure in rats to activation of mesolimbic dopamine neurons. Exposure of rats to 11,000 ppm of inhaled toluene produced time-dependent activation of dopamine neurons within the midbrain ventral tegmental area (VTA). In the rat brain slice preparation, perfusion with toluene (23-822 microM) also evoked an increase in activity of both dopamine and nondopamine neurons within the VTA. These excitatory effects could not be found in adjacent non-VTA nuclei, nor were they sensitive to the glutamate antagonists CGS19755 or CNQX. In behavioral studies, systemic administration of toluene produced a dose-dependent locomotor hyperactivity that was attenuated by either pretreatment with the D2 dopamine receptor antagonist remoxipride or by 6-hydroxydopamine lesions of the nucleus accumbens. These findings show that toluene can activate dopamine neurons within the mesolimbic reward pathway, an effect that may underlie the abuse potential of inhaled substances containing toluene.

  14. Carbon Nanotube Degradation in Macrophages: Live Nanoscale Monitoring and Understanding of Biological Pathway.

    Science.gov (United States)

    Elgrabli, Dan; Dachraoui, Walid; Ménard-Moyon, Cécilia; Liu, Xiao Jie; Bégin, Dominique; Bégin-Colin, Sylvie; Bianco, Alberto; Gazeau, Florence; Alloyeau, Damien

    2015-10-27

    Despite numerous applications, the cellular-clearance mechanism of multiwalled carbon nanotubes (MWCNTs) has not been clearly established yet. Previous in vitro studies showed the ability of oxidative enzymes to induce nanotube degradation. Interestingly, these enzymes have the common capacity to produce reactive oxygen species (ROS). Here, we combined material and life science approaches for revealing an intracellular way taken by macrophages to degrade carbon nanotubes. We report the in situ monitoring of ROS-mediated MWCNT degradation by liquid-cell transmission electron microscopy. Two degradation mechanisms induced by hydroxyl radicals were extracted from these unseen dynamic nanoscale investigations: a non-site-specific thinning process of the walls and a site-specific transversal drilling process on pre-existing defects of nanotubes. Remarkably, similar ROS-induced structural injuries were observed on MWCNTs after aging into macrophages from 1 to 7 days. Beside unraveling oxidative transformations of MWCNT structure, we elucidated an important, albeit not exclusive, biological pathway for MWCNT degradation in macrophages, involving NOX2 complex activation, superoxide production, and hydroxyl radical attack, which highlights the critical role of oxidative stress in cellular processing of MWCNTs.

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

    Science.gov (United States)

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

    2016-04-01

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

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

    Science.gov (United States)

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

    2016-04-01

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

  17. Development and distribution of PAG-immunoreactive neurons in the central pathway of trigeminal proprioception of the rat brainstem

    Institute of Scientific and Technical Information of China (English)

    PANG You-wang; LI Jin-lian

    2002-01-01

    Objective:To investigate the development and distribution of phosphate-activated glutaminase like immunoreactive (PAG-LI) neurons in the central pathway of trigeminal proprioception of the rat brainstem.Methods: The immunohistochemitry techniques were used. Results: (1) At embryonic day 17 (E17), PAGLI neurons were initially observed in the mesencephalic trigeminal nucleus (Vme). All PAG-LI neurons were large round neurons with moderate immunostaining. The immunoreactivity grew intense and attained adultlike pattern at P10. (2) Not until postnatal day 10 (P10) did a few PAG-LI neurons appear in the area ventral to the motor trigeminal nucleus (AVM) and area dorsal to the superior olivery nucleus (ADO), and not until P12 in the dorsomedial part of the subnucleus oralis of the spinal trigeminal nucleus (Vodm) and dorsomedial part of the principal sensory trigeminal nucleus (Vpdm). As development proceeded, more and more neurons in them were immunostained, and some PAG-LI neurons were detected in the lateral reticular formation adjacent to the Vodm(LRF)and the caudolateral part of the supratrigeminal nucleus (Vsup-CL) at P21.Conclusion: In the central pathway of trigeminal proprioception of the rat brainstem, PAG-LI neurons appeared during two stages: The first stage from E17 to P10, PAG-LI neurons appeared in the Vme and reached adult-like pattern; the second stage from P10 to P21, PAG-LI neurons appeared in the Vodm, LRF,Vpdm, Vsup-CL, ADO, AVM and gradually reached adult-like pattern. This might be relative to the establishment of jaw movement patterns.

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

    Science.gov (United States)

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

    2016-06-01

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

  19. Radionuclide migration pathways analysis for the Oak Ridge Central Waste Disposal Facility on the West Chestnut Ridge site

    International Nuclear Information System (INIS)

    A dose-to-man pathways analysis is performed for disposal of low-level radioactive waste at the Central Waste Disposal Facility on the West Chestnut Ridge Site. Both shallow land burial (trench) and aboveground (tumulus) disposal methods are considered. The waste volumes, characteristics, and radionuclide concentrations are those of waste streams anticipated from the Oak Ridge National Laboratory, the Y-12 Plant, and the Oak Ridge Gaseous Diffusion Plant. The site capacity for the waste streams is determined on the basis of the pathways analysis. The exposure pathways examined include (1) migration and transport of leachate from the waste disposal units to the Clinch River (via the groundwater medium for trench disposal and Ish Creek for tumulus disposal) and (2) those potentially associated with inadvertent intrusion following a 100-year period of institutional control: an individual resides on the site, inhales suspended particles of contaminated dust, ingests vegetables grown on the plot, consumes contaminated water from either an on-site well or from a nearby surface stream, and receives direct exposure from the contaminated soil. It is found that either disposal method would provide effective containment and isolation for the anticipated waste inventory. However, the proposed trench disposal method would provide more effective containment than tumuli because of sorption of some radionuclides in the soil. Persons outside the site boundary would receive radiation doses well below regulatory limits if they were to ingest water from the Clinch River. An inadvertent intruder could receive doses that approach regulatory limits; however, the likelihood of such intrusions and subsequent exposures is remote. 33 references, 31 figures, 28 tables

  20. mTOR activation is a biomarker and a central pathway to autoimmune disorders, cancer, obesity, and aging

    Science.gov (United States)

    Perl, Andras

    2015-01-01

    The mechanistic target of rapamycin (mTOR) is a ubiquitous serine/threonine kinase that plays pivotal roles in integrating growth signals on a cellular level. To support proliferation and survival under stress, two interacting complexes that harbor mTOR, mTORC1 and mTORC2, promote the transcription of genes involved in carbohydrate metabolism and lipogenesis, enhance protein translation, and inhibit autophagy. While rapamycin was originally developed as an inhibitor of T cell proliferation for preventing organ transplant rejection, its molecular target, mTOR, has been subsequently identified as a central regulator of metabolic cues that drive lineage specification in the immune system. Owing to oxidative stress, the activation of mTORC1 has emerged as a central pathway for the pathogenesis of systemic lupus erythematosus and other autoimmune diseases. Paradoxically, mTORC1 has been also identified as a mediator of the Warburg effect that allows cell survival under hypoxia. Rapamycin and new classes of mTOR inhibitors are being developed to block not only transplant rejection and autoimmunity but also to treat obesity and various forms of cancer. Through preventing these diseases, personalized mTOR blockade holds promise to extend life span. PMID:25907074

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

    Science.gov (United States)

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

    2016-04-01

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

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

    Science.gov (United States)

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

    2016-02-01

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

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

    Science.gov (United States)

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

    2016-02-01

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

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

    Science.gov (United States)

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

    2016-03-25

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

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

    Science.gov (United States)

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

    2016-03-25

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

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

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

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

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

    Science.gov (United States)

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

    2011-09-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Patrick Gonzalez; Benjamin Kroll; Carlos R. Vargas

    2006-01-10

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

  9. North and south: Regional footprints on the transition pathway towards a low carbon, global economy

    International Nuclear Information System (INIS)

    Environmental or 'ecological' footprints are indicators of resource consumption and waste absorption transformed on the basis of biologically productive land area required per capita with prevailing technology. They represent a partial measure of the extent to which the planet, its regions, or nations are moving along a sustainable development pathway. Such footprints vary between countries at different stages of economic development and varying geographic characteristics. A correlation equation for national environmental footprints is used, alongside international projections of population growth and gross regional income, to estimate the relative contributions of the peoples of the industrialised North and populous South that would be needed in order to secure climate-stabilising carbon reductions out to about 2100. The four so-called 'marker scenarios' produced by the Intergovernmental Panel on Climate Change are used to estimate the degree of energy efficiency improvement and carbon mitigation that is feasible. The present footprint projections suggest that a reduction in the consumption of biophysical assets across both the developing and industrialised world is indeed possible. However, the developing world's footprint is shown to overshoot that of the industrialised countries by around 2010-2015. It then levels out and starts to fall, on the most optimistic scenario, by about 2050. In order to achieve global sustainability in the 21st Century a serious commitment to environmental protection is required in both the industrialised North and the 'majority South'. That implies balancing population growth, economic well-being, and environmental impacts in the interests of all the people and wildlife on 'Spaceship Earth'.

  10. Global zero-carbon energy pathways using viable mixes of nuclear and renewables

    International Nuclear Information System (INIS)

    Highlights: • A proper mix of nuclear power and renewables achieves sustainable energy future. • A high nuclear share provides cost and land effectiveness compared to nuclear-free. • Only-renewable mix will increase negative economic and environmental impacts. • A deployment of advanced reactor technologies is essential to overcome limitations. - Abstract: What are the most viable global pathways for a major expansion of zero-carbon emissions electricity sources given the diversity of regional technical, socio-political and economic constraints? We modelled a range of zero-emissions energy scenarios across nations that were designed to meet projected final energy demand in 2060, and optimised to derive the best globally aggregated results in terms of minimising costs and land use (a surrogate for environmental impacts). We found that a delayed energy transition to a zero-emissions pathway will decrease investment costs (−$3,431 billion), but increase cumulative CO2 emissions (additional 696 Gt). A renewable-only scenario would convert >7.4% of the global land area to energy production, whereas a maximum nuclear scenario would affect <0.4% of land area, including mining, spent-fuel storage, and buffer zones. Moreover, a nuclear-free pathway would involve up to a 50% greater cumulative capital investment compared to a high nuclear penetration scenario ($73.7 trillion). However, for some nations with a high current share of renewables and a low projected future energy demand (e.g., Norway), pursuit of a higher nuclear share is suboptimal. In terms of the time frame for replacement of fossil fuels, achieving a global nuclear share of about 50% by 2060 would be a technically and economically plausible target if progressing at a pace of the average historical growth of nuclear power penetration in France from 1970 to 1986 (0.28 MWh person−1 year-1). For effective climate-change mitigation, a high penetration of nuclear in association with a nationally

  11. Oxidation state, bioavailability & biochemical pathway define the fate of carbon in soil

    Science.gov (United States)

    Kuzyakov, Yakov; Apostel, Carolin; Gunina, Anna; Herrmann, Anke M.; Dippold, Michaela

    2015-04-01

    Numerous experiments under laboratory and field conditions analyzed microbial utilization and mean residence time (MRT) of carbon (C) from plant and microbial residues as well as root exudates in soil. Most of these studies tested the effects of various environmental factors, such as temperature, soil moisture, texture etc. on these parameters. However, only a few studies compared the properties of the substances themselves and there is no conceptual framework based on biochemical pathways. We hypothesize that the fate of C from organic substances in soil strongly depends on the first step of their microbial utilization, specifically, on biochemical pathway and initial C oxidation state, as well as its bioavailability in soils, defined by its hydrophobicity and molecular weight. Here we introduce and evaluate a new conceptual framework based on the following parameters: 1) C oxidation state, 2) molecular weight and hydrophobicity, 3) initial biochemical pathway of a substance class in microbial cells. To assess these parameters, two databases were prepared based on the literature and own studies. The first database included only the studies with 14C or 13C position specific labeled sugars, amino acids, carboxylic acids, phenols and lipids in soil. This database allowed us to analyze microbial utilization and mineralization of organics to CO2 depending on their C oxidation state (OS) and on functional groups. Additionally, we calculated data on the bond electronegativity of all compounds investigated in these studies. The second data base included the results of 14C and 13C studies with uniformly labeled substances of various classes. This database considered the free enthalpie (Delta H) per C unit from a variety of substrates differing in their aromaticity, hydrophobicity/electronegativity and location of the substance on the van Krevelen diagram. In addition, we calculated the hydrophobicity from the electronegativity of the individual bonds and recorded their

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

    Science.gov (United States)

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

    2012-04-01

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

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

    Science.gov (United States)

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

    1998-01-01

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

  14. 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.

  15. Existence of Heme Oxygenase-carbon Monoxide-cyclic Guanosine Monophosphate Pathway in Human Trabecular Meshwork Cells In Vitro

    Institute of Scientific and Technical Information of China (English)

    李涛; 张虹; 梁峰

    2004-01-01

    To confirm the existence of heme oxygenase (HO)-carbon monoxide (CO)- cyclic guanosine monophosphate (cGMP) pathway in the cultured human trabecular meshwork cells (HTMCs) in vitro, and to evaluate the inductive role of hemin on this pathway, HTMCs of the third to fourth generation were cultured in vitro. Reverse transcripase-polymerase chain reaction (RT-PCR)was employed for detection of HO-1 and HO-2 mRNA. Immunohistochemical staining was used to detect HO-1 and HO-2 proteins. Hemin was added into the culture solution. The HO-1 mRNA lev els were quantified by RT-PCR. The relative amount of carbon monoxide released into the media was measured with the quantifying carbon monoxide hemoglobin (HbCO) by spectrophotometry.Radioimmunoassay was used to determine changes of cGMP in HTMCs. The results showed that cultured cells had the specific characteristics of HTMCs. Both HO-1 and HO-2 genes were expressed in HTMCs, as well as HO-1 and HO-2 proteins in HTMCs. Hemin induced HO-1 mRNA,HbCO and cGMP in a dose-dependent manner. In conclusion, HO-CO-cGMP pathway exists in the cultured HTMCs and can be induced by hemin. Pharmacological stimulation of HO-CO-cGMP pathway may constitute a novel therapeutic approach to rescuing glaucoma.

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

    Science.gov (United States)

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

    2016-05-01

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

  17. Influence of geology, regolith and soil on fluid flow pathways in an upland catchment in central NSW, Australia

    Science.gov (United States)

    Bernardi, Tony

    2014-05-01

    Influence of geology, regolith and soil on fluid flow pathways in an upland catchment in central NSW, Australia. Tony Bernardi and Leah Moore Dryland Salinity Hazard Mitigation Program (DSHMP), University of Canberra, ACT 2601, AUSTRALIA The diversity of salt expression in central NSW has defied classification because salt expression, mobilisation and transport is highly variable and is typically site specific. Hydrological models are extensively used to simulate possible outcomes for a range of land use changes to mitigate the mobilisation and transport of salt into the streams or across the land surface. The ability of these models to mimic reality can be variable thereby reducing the confidence in the models outputs and uptake of strategic management changes by the community. This study focuses on a 250 ha semi-arid sub-catchment of Little River catchment in central west NSW in the Murray-Darling Basin, Australia. We propose that an understanding the structure of the landforms and configuration of rock, regolith and soil materials at the study site influences fluid flow pathways in the landscape and can be related to observed variations in the chemical composition and salinity of surface and aquifer water. Preliminary geological mapping of the site identified the dominant rock type as a pink and grey dacite and in localised mid-slope areas, a coarsely crystalline biotite-phyric granodiorite. Samples were taken at regular intervals from natural exposures in eroded stream banks and in excavations made during the installation of neutron moisture meter tubes. In order to establish mineral weathering pathways, samples were taken from the relatively unweathered core to the outer weathered 'onion skins' of corestones on both substrates, and then up through the regolith profile, including the soil zone, to the land surface. X-ray diffraction (XRD) analysis and X-ray fluorescence (XRF) was conducted on the rock and soil/saprock samples. Electromagnetic induction (EMI

  18. Pathways of Organic-Carbon Oxidation in 3 Continental-Margin Sediments Rid A-8010-2010

    DEFF Research Database (Denmark)

    CANFIELD, DE; JØRGENSEN, BB; FOSSING, H.;

    1993-01-01

    We have combined several different methodologies to quantify rates of organic carbon mineralization by the various electron acceptors in sediments from the coast of Denmark and Norway. Rates of NH4+ and SIGMACO2 liberation in sediment incubations were used with O2 penetration depths to conclude...... that O2 respiration accounted for only between 3.6-17.4% of the total organic carbon oxidation. Dentrification was limited to a narrow zone just below the depth of O2 penetration, and was not a major carbon oxidation pathway. The processes of Fe reduction, Mn reduction and sulfate reduction dominated...... organic carbon mineralization, but their relative significance varied depending on the sediment. Where high concentrations of Mn-oxide were found (3-4 wt% Mn), only Mn reduction occurred. With lower Mn oxide concentrations more typical of coastal sediments, Fe reduction and sulfate reduction were most...

  19. Differential role of the nitric oxide pathway on delta(9)-THC-induced central nervous system effects in the mouse.

    Science.gov (United States)

    Azad, S C; Marsicano, G; Eberlein, I; Putzke, J; Zieglgänsberger, W; Spanagel, R; Lutz, B

    2001-02-01

    This study investigated whether the nitric oxide pathway was involved in the central effects of Delta(9)-tetrahydrocannabinol (Delta(9)-THC), the major psychoactive constituent of cannabis sativa. Body temperature, nociception and locomotion were measured in neuronal nitric oxide synthase (nNOS) knock-out (KO) mice and wild-type (WT) controls after intraperitoneal application of Delta(9)-THC. These Delta(9)-THC-induced effects are known to be mediated through the brain-type cannabinoid receptor 1 (CB1). Therefore, in situ hybridization (ISH) experiments were performed in the adult murine brain to determine possible changes in CB1 mRNA levels in nNOS-KO, compared with WT mice, and to reveal brain areas where CB1 and nNOS were coexpressed in the same neurons. We found that an intraperitoneal injection of 10 mg/kg Delta(9)-THC led to the same increase in the hot plate latencies in both genotypes, suggesting that Delta(9)-THC-mediated antinociception does not involve nNOS. In contrast, a significant Delta(9)-THC-induced decrease of body temperature and locomotor activity was only observed in WT, but not in nNOS-KO mice. ISH revealed significantly lower levels of CB1 mRNA in the ventromedial hypothalamus (VMH) and the caudate putamen (Cpu) of the nNOS-KO animals, compared with WT mice. Both areas are known to be among the regions involved in cannabinoid-induced thermoregulation and decrease of locomotion. A numerical evaluation of nNOS/CB1 coexpression showed that approximately half of the nNOS-positive cells in the dorsolateral Cpu also express low levels of CB1. ISH of adjacent serial sections with CB1 and nNOS, revealed expression of both transcripts in VMH, suggesting that numerous nNOS-positive cells of VMH coexpress CB1. Our findings indicate that the nitric oxide pathway is involved in some, but not all of the central effects of Delta(9)-THC.

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

    Directory of Open Access Journals (Sweden)

    Jacob P Bitoun

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

  1. Soil Carbon Dynamics Along the Pathway From Diverse Microbial Carbon to Humus in a Temperate and Tropical Forest

    Science.gov (United States)

    Throckmorton, H. M.; Bird, J. A.; Firestone, M. K.; Horwath, W. R.

    2008-12-01

    This research investigates the importance of microbial biochemistry to humification pathways in two climatically different forest ecosystems; Blodgett forest (BF), a temperate forest in the Sierra Nevada and Luquillo forest (LF), a tropical forest in Puerto Rico. Non-living 13C enriched temperate and tropical microorganisms from four biochemically contrasting microbial groups (fungi, actinomycetes, bacteria gram (+), and bacteria gram (-)) were separately added to soil at both sites in a reciprocal transplant experiment. Decomposition rates were substantially greater at LF than BF for all microbial inputs. Although there were initial differences in microbial C turnover and recovery within the soil microbial biomass and dissolved organic carbon pools for unique microbial C inputs at both sites, over time treatment differences converge within each site and the quality of input microbial C becomes less important to C remaining and maintained within these soil C pools. Physical soil fractionation revealed important trends which illustrate the role of the soil mineral matrix to protect and stabilize C in soil. Results indicate different C turnover rates associated with the light, aggregate- occluded, and mineral-associated soil fractions at both sites. At BF input C recovered within the light and mineral-associated fractions decreased substantially over time (1 to 13 months), while C occluded within aggregates only slightly decreased. Similarly, LF soils exhibit only a slight decrease in aggregate-occluded C over time (0.5 to 3.5 months), while C recovered within the light fraction decreased substantially; however, unlike BF, LF soils exhibited only a slight decrease in C recovered within the mineral fraction. The distribution of total C among these physical soil pools differs substantially for either site, suggesting differences in the relative importance of the mineral matrix to protect and stabilize C. Preliminary compound-specific isotope analyses employing

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

    Science.gov (United States)

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

    2013-12-01

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

  3. Biosynthetic Pathways of Vibrio succinogenes growing with fumarate as terminal electron acceptor and sole carbon source.

    Science.gov (United States)

    Bronder, M; Mell, H; Stupperich, E; Kröger, A

    1982-05-01

    1. With fumarate as the terminal electron acceptor and either H2 or formate as donor, Vibrio succinogenes could grow anaerobically in a mineral medium using fumarate as the sole carbon source. Both the growth rate and the cell yield were increased when glutamate was also present in the medium. 2. Glutamate was incorporated only into the amino acids of the glutamate family (glutamate, glutamine, proline and arginine) of the protein. The residual cell constituents were synthesized from fumarate. 3. Pyruvate and phosphoenolpyruvate, as the central intermediates of most of the cell constituents, were formed through the action of malic enzyme and phosphoenolpyruvate synthetase. Fructose-1,6-bisphosphate aldolase was present in the bacterium suggesting that this enzyme is involved in carbohydrate synthesis. 4. In the absence of added glutamate the amino acids of the glutamate family were synthesized from fumarate via citrate. The enzymes involved in glutamate synthesis were present. 5. During growth in the presence of glutamate, net reducing equivalents were needed for cell synthesis. Glutamate and not H2 or formate was used as the source of these reducing equivalents. For this purpose part of the glutamate was oxidized to yield succinate and CO2. 6. The alpha-ketoglutarate dehydrogenase involved in this reaction was found to use ferredoxin as the electron acceptor. The ferredoxin of the bacterium was reoxidized by means of a NADP-ferredoxin oxidoreductase. Enzymes catalyzing the reduction of NAD, NADP or ferredoxin by H2 or formate were not detected in the bacterium. PMID:7103660

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

    Directory of Open Access Journals (Sweden)

    Serena S D'Souza

    2016-01-01

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

  5. The coupling of glycolysis and the Rubisco-based pathway through the non-oxidative pentose phosphate pathway to achieve low carbon dioxide emission fermentation.

    Science.gov (United States)

    Li, Ya-Han; Ou-Yang, Fan-Yu; Yang, Cheng-Han; Li, Si-Yu

    2015-01-01

    In this study, Rubisco-based engineered Escherichia coli, containing two heterologous enzymes of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) and phosphoribulokinase (PrkA), has been shown to be capable of the in situ recycling of carbon dioxide (CO2) during glycolysis. Two alternative approaches have been proposed to further enhance the carbon flow from glycolysis to a Rubisco-based pathway through the non-oxidative pentose phosphate pathway (NOPPP). The first is achieved by elevating the expression of transketolase I (TktA) and the second by blocking the native oxidation-decarboxylation reaction of E. coli by deleting the zwf gene from the chromosome (designated as JB/pTA and MZB, respectively). Decreases in the CO2 yield and the CO2 evolution per unit mole of ethanol production by at least 81% and 40% are observed. It is demonstrated in this study that the production of one mole of ethanol using E. coli strain MZB, the upper limit of CO2 emission is 0.052mol.

  6. Modulation of the Ca(2+) signaling pathway by celangulin I in the central neurons of Spodoptera exigua.

    Science.gov (United States)

    Li, Yuxin; Lian, Xihong; Wan, Yinging; Wang, Duoyi; Chen, Wei; Di, Fengjuan; Wu, Wenjun; Li, Zhengming

    2016-02-01

    Celangulin I is an insecticidal component isolated from Chinese bittersweet Celastrus angulatus. The present study explored the possible effects of celangulin I on the calcium signaling pathway, especially on the L-type Ca(2+) channel and the calcium channels in the endoplasmic reticulum in the central neurons isolated from the third instar larvae of Spodoptera exigua using whole-cell patch-clamp and calcium imaging technique. The results showed that celangulin I could activate the high voltage-gated calcium channel at the concentration of 150μM. The peak currents were increased by 17% of the initial value at the end of the 10-min recording after treated with celangulin I. The rises of intracellular calcium ion concentration ([Ca(2+)]i) in neurons treated by celangulin I showed that the effects of celangulin I were concentration-dependent. Activation of the RyRs by ryanodine decreased the calcium release induced by celangulin I, indicating that celangulin I exerts effect on insect RyRs. Furthermore, we also provided evidence for the first time that celangulin I activates inositol 1,4,5-trisphosphate (IP3) sensitive intracellular calcium release channels in the endoplasmic reticulum third instar larvae neurons of S. exigua. Plausibly, these experimental results can explain the characteristic symptoms of anesthesia and paralysis in celangulin I treated insects. PMID:26821661

  7. Libidibia ferrea Mature Seeds Promote Antinociceptive Effect by Peripheral and Central Pathway: Possible Involvement of Opioid and Cholinergic Receptors

    Directory of Open Access Journals (Sweden)

    Luis Armando Sawada

    2014-01-01

    Full Text Available Libidibia ferrea (LF is a medicinal plant that holds many pharmacological properties. We evaluated the antinociceptive effect in the LF aqueous seed extract and Lipidic Portion of Libidibia ferrea (LPLF, partially elucidating their mechanisms. Histochemical tests and Gas chromatography of the LPLF were performed to characterize its fatty acids. Acetic acid-induced abdominal constriction, formalin-induced pain, and hot-plate test in mice were employed in the study. In all experiments, aqueous extract or LPLF was administered systemically at the doses of 1, 5, and 10 mg/kg. LF aqueous seed extract and LPLF demonstrated a dose-dependent antinociceptive effect in all tests indicating both peripheral anti-inflammatory and central analgesia properties. Also, the use of atropine (5 mg/kg, naloxone (5 mg/kg in the abdominal writhing test was able to reverse the antinociceptive effect of the LPLF, indicating that at least one of LF lipids components is responsible for the dose related antinociceptive action in chemical and thermal models of nociception in mice. Together, the present results suggested that Libidibia ferrea induced antinociceptive activity is possibly related to its ability to inhibit opioid, cholinergic receptors, and cyclooxygenase-2 pathway, since its main component, linoleic acid, has been demonstrated to produce such effect in previous studies.

  8. Libidibia ferrea Mature Seeds Promote Antinociceptive Effect by Peripheral and Central Pathway: Possible Involvement of Opioid and Cholinergic Receptors

    Science.gov (United States)

    Sawada, Luis Armando; Monteiro, Vanessa Sâmia da Conçeição; Rabelo, Guilherme Rodrigues; Dias, Germana Bueno; Da Cunha, Maura; do Nascimento, José Luiz Martins; Bastos, Gilmara de Nazareth Tavares

    2014-01-01

    Libidibia ferrea (LF) is a medicinal plant that holds many pharmacological properties. We evaluated the antinociceptive effect in the LF aqueous seed extract and Lipidic Portion of Libidibia ferrea (LPLF), partially elucidating their mechanisms. Histochemical tests and Gas chromatography of the LPLF were performed to characterize its fatty acids. Acetic acid-induced abdominal constriction, formalin-induced pain, and hot-plate test in mice were employed in the study. In all experiments, aqueous extract or LPLF was administered systemically at the doses of 1, 5, and 10 mg/kg. LF aqueous seed extract and LPLF demonstrated a dose-dependent antinociceptive effect in all tests indicating both peripheral anti-inflammatory and central analgesia properties. Also, the use of atropine (5 mg/kg), naloxone (5 mg/kg) in the abdominal writhing test was able to reverse the antinociceptive effect of the LPLF, indicating that at least one of LF lipids components is responsible for the dose related antinociceptive action in chemical and thermal models of nociception in mice. Together, the present results suggested that Libidibia ferrea induced antinociceptive activity is possibly related to its ability to inhibit opioid, cholinergic receptors, and cyclooxygenase-2 pathway, since its main component, linoleic acid, has been demonstrated to produce such effect in previous studies. PMID:24860820

  9. Measurement of black carbon at Syowa station, Antarctica: seasonal variation, transport processes and pathways

    Directory of Open Access Journals (Sweden)

    K. Hara

    2008-05-01

    Full Text Available Measurement of black carbon (BC was carried out at Syowa station Antarctica (69° S, 39° E from February 2004 until January 2007. The BC concentration at Syowa ranged from below detection to 176 ng m−3 during the measurements. Higher BC concentrations were observed mostly under strong wind (blizzard conditions due to the approach of a cyclone and blocking event. The BC-rich air masses traveled from the lower troposphere of the Atlantic and Indian Oceans to Syowa (Antarctic coast. During the summer (November–February, the BC concentration showed a diurnal variation together with surface wind speed and increased in the katabatic wind from the Antarctic continent. Considering the low BC source strength in the Antarctic continent, the higher BC concentration in the continental air (katabatic wind might be caused by long range transport of BC via the free troposphere from mid- and low- latitudes. The seasonal variation of BC at Syowa had a maximum in August, while at the other coastal stations (Halley, Neumayer, and Ferraz and the continental station (Amundsen-Scott, the maximum occurred in October. This difference may result from different transport pathways and scavenging of BC by precipitation during the transport from the source regions. During the austral summer, long-range transport of BC via the free troposphere is likely to make an important contribution to the ambient BC concentration. The BC transport flux indicated that BC injection into the Antarctic region strongly depended on the frequency of storm (blizzard conditions. The seasonal variation of BC transport flux increased by 290 mg m−2 month−1 in winter–spring when blizzards frequently occurred, whereas the flux decreased to lower than 50 mg m−2 month−1 in the summer with infrequent blizzards.

  10. Metaproteomics of a gutless marine worm and its symbiotic microbial community reveal unusual pathways for carbon and energy use

    Energy Technology Data Exchange (ETDEWEB)

    Kleiner, Manuel [Max Planck Institute for Marine Microbiology; Wentrop, C. [Max Planck Institute for Marine Microbiology; Lott, C. [Max Planck Institute for Marine Microbiology; Teeling, Hanno [Max Planck Institute for Marine Microbiology; Wetzel, Silke [Max Planck Institute for Marine Microbiology; Young, Jacque C [ORNL; Chang, Y. [Oak Ridge National Laboratory (ORNL); Shah, Manesh B [ORNL; Verberkmoes, Nathan C [ORNL; Zarzycki, Jan [University of Freiburg, Germany; Fuchs, Georg [University of Freiburg, Germany; Markert, Stephanie [Institute of Marine Biotechnology, Germany; Hempel, Kristina [Institute for Microbiology, Germany

    2012-01-01

    Low nutrient and energy availability has led to the evolution of numerous strategies for overcoming these limitations, of which symbiotic associations represent a key mechanism. Particularly striking are the associations between chemosynthetic bacteria and marine animals that thrive in nutrient-poor environments such as the deep-sea because the symbionts allow their hosts to grow on inorganic energy and carbon sources such as sulfide and CO2. Remarkably little is known about the physiological strategies that enable chemosynthetic symbioses to colonize oligotrophic environments. In this study, we used metaproteomics and metabolomics to investigate the intricate network of metabolic interactions in the chemosynthetic association between Olavius algarvensis, a gutless marine worm, and its bacterial symbionts. We propose novel pathways for coping with energy and nutrient limitation, some of which may be widespread in both free-living and symbiotic bacteria. These include (i) a pathway for symbiont assimilation of the host waste products acetate, propionate, succinate and malate, (ii) the potential use of carbon monoxide as an energy source, a substrate previously not known to play a role in marine invertebrate symbioses, (iii) the potential use of hydrogen as an energy source, (iv) the strong expression of high affinity uptake transporters, and (v) novel energy efficient steps in CO2 fixation and sulfate reduction. The high expression of proteins involved in pathways for energy and carbon uptake and conservation in the O. algarvensis symbiosis indicates that the oligotrophic nature of its environment exerted a strong selective pressure in shaping these associations.

  11. Pathways to a low-carbon economy for the UK with the macro-econometric E3MG model

    International Nuclear Information System (INIS)

    This paper examines different carbon pathways for achieving deep CO2 reduction targets for the UK using a macro-econometric hybrid model E3MG, which stands for Energy-Economy-Environment Model at the Global level. The E3MG, with the UK as one of its regions, combines a top-down approach for modeling the global economy and for estimating the aggregate and disaggregate energy demand and a bottom-up approach (Energy Technology subModel, ETM) for simulating the power sector, which then provides feedback to the energy demand equations and the whole economy. The ETM submodel uses a probabilistic approach and historical data for estimating the penetration levels of the different technologies, considering their economic, technical and environmental characteristics. Three pathway scenarios (CFH, CLC and CAM) simulate the CO2 reduction by 40%, 60% and 80% by 2050 compared to 1990 levels respectively and are compared with a reference scenario (REF), with no reduction target. The targets are modeled as the UK contribution to an international mitigation effort, such as achieving the G8 reduction targets, which is a more realistic political framework for the UK to move towards deep reductions rather than moving alone. This paper aims to provide modeling evidence that deep reduction targets can be met through different carbon pathways while also assessing the macroeconomic effects of the pathways on GDP and investment.

  12. Graphene/single-walled carbon nanotube hybrids promoting osteogenic differentiation of mesenchymal stem cells by activating p38 signaling pathway

    Science.gov (United States)

    Yan, Xinxin; Yang, Wen; Shao, Zengwu; Yang, Shuhua; Liu, Xianzhe

    2016-01-01

    Carbon nanomaterials are becoming increasingly significant in biomedical fields since they exhibit exceptional physicochemical and biocompatible properties. Today, the stem cells offer potentially new therapeutic approaches in tissue engineering and regenerative medicine. However, the induction of differentiation into specific lineages remains challenging, which provoked us to explore the biomedical applications of carbon nanomaterials in stem cells. In this study, we investigated the interactions between graphene/single-walled carbon nanotube (G/SWCNT) hybrids and rat mesenchymal stem cells (rMSCs) and focused on the proliferation and differentiation of rMSCs treated with G/SWCNT hybrids. Cell viability and morphology were evaluated using cell counting kit-8 assay and immunofluorescence staining, respectively. Osteogenic differentiation evaluated by alkaline phosphatase activity of MSCs proved to be higher after treatment with G/SWCNT hybrids, and the mineralized matrix nodule formation was also enhanced. In addition, the expression levels of osteogenic-associated genes were upregulated, while the adipocyte-specific markers were downregulated. Consistent with these results, we illustrated that the effect of G/SWCNT hybrids on the process of osteogenic differentiation of rMSCs can be modulated by activating the p38 signaling pathway and inhibiting the extracellular signal-regulated kinase 1/2 pathway. Nevertheless, our study suggests that carbon nanomaterials offer a promising platform for regenerative medicine in the near future.

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2013-04-01

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

  15. Pathways to malaria persistence in remote central Vietnam: a mixed-method study of health care and the community

    Directory of Open Access Journals (Sweden)

    Doan Nhan H

    2009-03-01

    Full Text Available Abstract Background There is increasing interest in underlying socio-cultural, economic, environmental and health-system influences on the persistence of malaria. Vietnam is a Mekong regional 'success story' after dramatic declines in malaria incidence following introduction of a national control program providing free bed-nets, diagnosis and treatment. Malaria has largely retreated to pockets near international borders in central Vietnam, where it remains a burden particularly among impoverished ethnic minorities. In these areas commune and village health workers are lynchpins of the program. This study in the central province of Quang Tri aimed to contribute to more effective malaria control in Vietnam by documenting the non-biological pathways to malaria persistence in two districts. Methods Multiple and mixed (qualitative and quantitative methods were used. The formative stage comprised community meetings, observation of bed-net use, and focus group discussions and semi-structured interviews with health managers, providers and community. Formative results were used to guide development of tools for the assessment stage, which included a provider quiz, structured surveys with 160 community members and 16 village health workers, and quality check of microscopy facilities and health records at district and commune levels. Descriptive statistics and chi-square analysis were used for quantitative data. Results The study's key findings were the inadequacy of bed-nets (only 45% of households were fully covered and sub-optimal diagnosis and treatment at local levels. Bed-net insufficiencies were exacerbated by customary sleeping patterns and population mobility. While care at district level seemed good, about a third of patients reportedly self-discharged early and many were lost to follow-up. Commune and village data suggested that approximately half of febrile patients were treated presumptively, and 10 village health workers did not carry

  16. A Numerical Study of the Effect of Periodic Nutrient Supply on Pathways of Carbon in a Coastal Upwelling Regime

    Science.gov (United States)

    Carr, Mary-Elena

    1998-01-01

    A size-based ecosystem model was modified to include periodic upwelling events and used to evaluate the effect of episodic nutrient supply on the standing stock, carbon uptake, and carbon flow into mesozooplankton grazing and sinking flux in a coastal upwelling regime. Two ecosystem configurations were compared: a single food chain made up of net phytoplankton and mesozooplankton (one autotroph and one heterotroph, A1H1), and three interconnected food chains plus bacteria (three autotrophs and four heterotrophs, A3H4). The carbon pathways in the A1H1 simulations were under stronger physical control than those of the A3H4 runs, where the small size classes are not affected by frequent upwelling events. In the more complex food web simulations, the microbial pathway determines the total carbon uptake and grazing rates, and regenerated nitrogen accounts for more than half of the total primary production for periods of 20 days or longer between events. By contrast, new production, export of carbon through sinking and mesozooplankton grazing are more important in the A1H1 simulations. In the A3H4 simulations, the turnover time scale of the autotroph biomass increases as the period between upwelling events increases, because of the larger contribution of slow-growing net phytoplankton. The upwelling period was characterized for three upwelling sites from the alongshore wind speed measured by the NASA Scatterometer (NSCAT) and the corresponding model output compared with literature data. This validation exercise for three upwelling sites and a downstream embayment suggests that standing stock, carbon uptake and size fractionation were best supported by the A3H4 simulations, while the simulated sinking fluxes are not distinguishable in the two configurations.

  17. PI3K and MEK1/2 molecular pathways are involved in the erythropoietin-mediated regulation of the central respiratory command.

    Science.gov (United States)

    Caravagna, Céline; Soliz, Jorge

    2015-01-15

    Erythropoietin stimulation modulates the central respiratory command in newborn mice. Specifically, the central respiratory depression induced by hypoxia is attenuated by acute (1h) or abolished by chronic erythropoietin stimulation. However, the underlying mechanisms remain unknown. As MEK and PI3K pathways are commonly involved in Epo-mediated effects of neuroprotection and erythropoiesis, we investigated here the implication of PI3K and MEK1/2 in the Epo-mediated regulation of the central respiratory command. To this end, in vitro brainstem-spinal cord preparations from 3 days old transgenic (Tg21; constitutively overexpressing erythropoietin in the brain specifically) and control mice were used. Our results show that blockade of PI3K or MEK1/2 stimulates normoxic bursts frequency in Tg21 preparations and abolish hypoxia-induced frequency depression in control preparations. These results show that MEK1/2 and PI3K pathways are involved in the Epo-mediated regulation of the central respiratory command. Moreover, this is the first demonstration that MEK1/2 and PI3K are involved in the brainstem central respiratory command. PMID:25462838

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

    Directory of Open Access Journals (Sweden)

    S. Nordmann

    2014-06-01

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

  19. Analysis of oxygen sources and reaction pathways of carbon support corrosion at the cathode in PEMFC using oxygen-18 DEMS

    Energy Technology Data Exchange (ETDEWEB)

    Li Wei [Department of Chemical and Biological Engineering, University of Alabama, Box 870203, Tuscaloosa AL 35487-0203 (United States); Lane, Alan M., E-mail: alane@eng.ua.ed [Department of Chemical and Biological Engineering, University of Alabama, Box 870203, Tuscaloosa AL 35487-0203 (United States)

    2010-09-01

    Oxygen gas, water used to humidify the gases, and surface oxides originated from the carbon black and catalyst preparation are the three possible oxygen sources contributing to carbon support corrosion (CSC) at the cathode in proton exchange membrane fuel cells (PEMFC). To discriminate among them, oxygen was isotopically labeled by replacing regular water with oxygen-18 ({sup 18}O) enriched water (H{sub 2}{sup 18}O, 98%) in differential electrochemical mass spectrometry (DEMS). The DEMS spectra of the cathode exhaust gases O{sub 2}, O{sup 18}O, {sup 18}O{sub 2}, CO{sub 2}, CO{sup 18}O and C{sup 18}O{sub 2} (m/z equal to 32, 34, 36, 44, 46 and 48 correspondingly), sampled by a mass spectrometer during cyclic voltammetry (potential cycled for 100-1400 mV at the rate of 10 mV s{sup -1}) and chronoamperometry, were analyzed to identify the sources of oxygen, identify mechanistic pathways, and classify the surface oxides on carbon for CSC. It was found that water is the main direct oxygen source for CSC. Water reacts with carbon to produce at least three types of carbon surface oxides, which are then further oxidized with water to produce CO{sub 2} in different potential ranges.

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

    Institute of Scientific and Technical Information of China (English)

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

    2009-01-01

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

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

    Science.gov (United States)

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

    2015-09-01

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

  2. Magnetic resonance imaging study of lumbosacral spinal cord nerves before artificial somatic-central nervous system-autonomic reflex pathway establish ment

    International Nuclear Information System (INIS)

    Objective: To investigate the value of MRI as imaging technique for lumbosacral spinal nerves before artificial somatic-central nervous system-autonomic reflex pathway establish ment. Methods: Conventional MRI and T2W CISS 3D were performed in 10 patients with neurogenic bladder planned for the operation of artificial somatic-central nervous system-autonomic reflex pathway. The Three-dimensional data were then constructed into composite images using a standard multiple planar reformation (MPR). Results: Five patients showed tethered spinal cord syndrome, whose spinal cord nerves were circuitous distributed and had abnormity number when penetrated the dura. Of these 5 patients, one patient was accompanied by spinal cord vas malformation. Four patients had vertebral fracture and spinal injury, and the other one patients demonstrated tumor in vertebral canal on MRI examinations. The spinal cord nerves in these 5 patients floated down river and had normal number of spinal cord nerves. Conclusion: Conventional MRI and T2W CISS 3D MRI were essential for the pre-operative planning of artificial somatic-central nervous system-autonomic reflex pathway, especially in patients with tethered spinal cord syndrome. Spinal cord nerves distribute and anterior and posterior roots array can be clearly showed by MPR. (authors)

  3. Interleukin-15 plays a central role in human kidney physiology and cancer through the γc signaling pathway.

    Directory of Open Access Journals (Sweden)

    Julien Giron-Michel

    Full Text Available The ability of Interleukin-15 (IL-15 to activate many immune antitumor mechanisms renders the cytokine a good candidate for the therapy of solid tumors, particularly renal cell carcinoma. Although IL-15 is being currently used in clinical trials, the function of the cytokine on kidney's components has not been extensively studied; we thus investigated the role of IL-15 on normal and tumor renal epithelial cells. Herein, we analyzed the expression and the biological functions of IL-15 in normal renal proximal tubuli (RPTEC and in their neoplastic counterparts, the renal clear cell carcinomas (RCC. This study shows that RPTEC express a functional heterotrimeric IL-15Rαβγc complex whose stimulation with physiologic concentrations of rhIL-15 is sufficient to inhibit epithelial mesenchymal transition (EMT commitment preserving E-cadherin expression. Indeed, IL-15 is not only a survival factor for epithelial cells, but it can also preserve the renal epithelial phenotype through the γc-signaling pathway, demonstrating that the cytokine possess a wide range of action in epithelial homeostasis. In contrast, in RCC in vitro and in vivo studies reveal a defect in the expression of γc-receptor and JAK3 associated kinase, which strongly impacts IL-15 signaling. Indeed, in the absence of the γc/JAK3 couple we demonstrate the assembly of an unprecedented functional high affinity IL-15Rαβ heterodimer, that in response to physiologic concentrations of IL-15, triggers an unbalanced signal causing the down-regulation of the tumor suppressor gene E-cadherin, favoring RCC EMT process. Remarkably, the rescue of IL-15/γc-dependent signaling (STAT5, by co-transfecting γc and JAK3 in RCC, inhibits EMT reversion. In conclusion, these data highlight the central role of IL-15 and γc-receptor signaling in renal homeostasis through the control of E-cadherin expression and preservation of epithelial phenotype both in RPTEC (up-regulation and RCC (down-regulation.

  4. The putrescine biosynthesis pathway in Lactococcus lactis is transcriptionally regulated by carbon catabolic repression, mediated by CcpA.

    Science.gov (United States)

    Linares, Daniel M; del Río, Beatriz; Ladero, Victor; Redruello, Begoña; Martín, María Cruz; Fernández, María; Alvarez, Miguel A

    2013-07-01

    Lactococcus lactis is the lactic acid bacterium most widely used by the dairy industry as a starter for the manufacture of fermented products such as cheese and buttermilk. However, some strains produce putrescine from agmatine via the agmatine deiminase (AGDI) pathway. The proteins involved in this pathway, including those necessary for agmatine uptake and conversion into putrescine, are encoded by the aguB, aguD, aguA and aguC genes, which together form an operon. This paper reports the mechanism of regulation of putrescine biosynthesis in L. lactis. It is shown that the aguBDAC operon, which contains a cre site at the promoter of aguB (the first gene of the operon), is transcriptionally regulated by carbon catabolic repression (CCR) mediated by the catabolite control protein CcpA. PMID:23688550

  5. Mimicking a natural pathway for de novo biosynthesis: natural vanillin production from accessible carbon sources

    OpenAIRE

    Jun Ni; Fei Tao; Huaiqing Du; Ping Xu

    2015-01-01

    Plant secondary metabolites have been attracting people’s attention for centuries, due to their potentials; however, their production is still difficult and costly. The rich diversity of microbes and microbial genome sequence data provide unprecedented gene resources that enable to develop efficient artificial pathways in microorganisms. Here, by mimicking a natural pathway of plants using microbial genes, a new metabolic route was developed in E. coli for the synthesis of vanillin, the most ...

  6. Widespread occurrence of two carbon fixation pathways in tubeworm endosymbionts: lessons from hydrothermal vent associated tubeworms from the Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    Vera eThiel

    2012-12-01

    Full Text Available Vestimentiferan tubeworms (siboglinid polychaetes of the genus Lamellibrachia are common members of cold-seep faunal communities and have also been found at sedimented hydrothermal vent sites in the Pacific. As they lack a digestive system, they are nourished by chemoautotrophic bacterial endosymbionts growing in a specialized tissue called the trophosome. Here we present the results of investigations of tubeworms and endosymbionts from a shallow hydrothermal vent field in the Western Mediterranean Sea. The tubeworms, which are the first reported vent-associated tubeworms outside the Pacific, are identified as Lamellibrachia anaximandri using mitochondrial ribosomal and cytochrome oxidase I gene sequences. They harbor a single gammaproteobacterial endosymbiont. Carbon isotopic data, as well as the analysis of genes involved in carbon and sulfur metabolism indicate a sulfide-oxidizing chemoautotrophic endosymbiont. The detection of a hydrogenase gene fragment suggests the potential for hydrogen oxidation as alternative energy source. Surprisingly, the endosymbiont harbors genes for two different carbon fixation pathways, the Calvin-Benson-Bassham (CBB cycle as well as the reductive tricarboxylic acid (rTCA cycle, as has been reported for the endosymbiont of the giant vent tubeworm Riftia pachyptila. In addition to RubisCO genes we detected ATP citrate lyase (ACL, the key enzyme of the rTCA cycle type II gene sequences using newly designed primer sets. Comparative investigations with additional tubeworm species (Lamellibrachia luymesi, Lamellibrachia sp. 1, Lamellibrachia sp. 2, Escarpia laminata, Seepiophila jonesi from multiple cold seep sites in the Gulf of Mexico revealed the presence of acl genes in these species as well. Thus, our study suggests that the presence of two different carbon fixation pathways, the CBB cycle and the rTCA cycle, is not restricted to the Riftia endosymbiont, but rather might be common in vestimentiferan tubeworm

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-09-01

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

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

    OpenAIRE

    Brown, A T; Breeding, L C

    1980-01-01

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

  10. The solar photovoltaics wedge: pathways for growth and potential carbon mitigation in the US

    International Nuclear Information System (INIS)

    The challenge of stabilizing global carbon emissions over the next 50 years has been framed in the context of finding seven 1.0 Gton C/year carbon reduction wedges. Solar photovoltaics (PV) could provide at least one carbon wedge, but will require significant growth in PV manufacturing capacity. The actual amount of installed PV capacity required to reach wedge-level carbon reductions will vary greatly depending on the mix of avoided fuels and the additional emissions from manufacturing PV capacity. In this work, we find that the US could reduce its carbon emissions by 0.25 Gton C/year, equal to the fraction of a global carbon wedge proportional to its current domestic electricity use, by installing 792-811 GW of PV capacity. We evaluate a series of PV growth scenarios and find that wedge-level reductions could be met by increasing PV manufacturing capacity and annual installations by 0.95 GW/year/year each year from 2009 to 2050 or by increasing up to 4 GW/year/year for a period of 4-17 years for early and late growth scenarios. This challenge of increasing PV manufacturing capacity and market demand is significant but not out of line with the recent rapid growth in both the global and US PV industry. We find that the rapid growth in PV manufacturing capacity leads to a short term increase in carbon emissions from the US electric sector. However, this increase is small, contributing less than an additional 0.3% to electric sector emissions for less than 4.5 years, alleviating recent concern regarding carbon emissions from rapid PV growth scenarios.

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

    Institute of Scientific and Technical Information of China (English)

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

    2015-01-01

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

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

    NARCIS (Netherlands)

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

    2006-01-01

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

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

    DEFF Research Database (Denmark)

    Machado, Daniel; Herrgard, Markus; Rocha, Isabel

    2015-01-01

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

  14. Mimicking a natural pathway for de novo biosynthesis: natural vanillin production from accessible carbon sources.

    Science.gov (United States)

    Ni, Jun; Tao, Fei; Du, Huaiqing; Xu, Ping

    2015-01-01

    Plant secondary metabolites have been attracting people's attention for centuries, due to their potentials; however, their production is still difficult and costly. The rich diversity of microbes and microbial genome sequence data provide unprecedented gene resources that enable to develop efficient artificial pathways in microorganisms. Here, by mimicking a natural pathway of plants using microbial genes, a new metabolic route was developed in E. coli for the synthesis of vanillin, the most widely used flavoring agent. A series of factors were systematically investigated for raising production, including efficiency and suitability of genes, gene dosage, and culture media. The metabolically engineered strain produced 97.2 mg/L vanillin from l-tyrosine, 19.3 mg/L from glucose, 13.3 mg/L from xylose and 24.7 mg/L from glycerol. These results show that the metabolic route enables production of natural vanillin from low-cost substrates, suggesting that it is a good strategy to mimick natural pathways for artificial pathway design. PMID:26329726

  15. Mimicking a natural pathway for de novo biosynthesis: natural vanillin production from accessible carbon sources.

    Science.gov (United States)

    Ni, Jun; Tao, Fei; Du, Huaiqing; Xu, Ping

    2015-09-02

    Plant secondary metabolites have been attracting people's attention for centuries, due to their potentials; however, their production is still difficult and costly. The rich diversity of microbes and microbial genome sequence data provide unprecedented gene resources that enable to develop efficient artificial pathways in microorganisms. Here, by mimicking a natural pathway of plants using microbial genes, a new metabolic route was developed in E. coli for the synthesis of vanillin, the most widely used flavoring agent. A series of factors were systematically investigated for raising production, including efficiency and suitability of genes, gene dosage, and culture media. The metabolically engineered strain produced 97.2 mg/L vanillin from l-tyrosine, 19.3 mg/L from glucose, 13.3 mg/L from xylose and 24.7 mg/L from glycerol. These results show that the metabolic route enables production of natural vanillin from low-cost substrates, suggesting that it is a good strategy to mimick natural pathways for artificial pathway design.

  16. Trophic structure and pathways of biogenic carbon flow in the eastern North Water Polynya

    Science.gov (United States)

    Tremblay, Jean-Éric; Hattori, Hiroshi; Michel, Christine; Ringuette, Marc; Mei, Zhi-Ping; Lovejoy, Connie; Fortier, Louis; Hobson, Keith A.; Amiel, David; Cochran, Kirk

    2006-10-01

    In the eastern North Water, most of the estimated annual new and net production of carbon (C) occurred during the main diatom bloom in 1998. During the bloom, at least 30% of total and new phytoplankton production occurred as dissolved organic carbon (DOC) and was unavailable for short-term assimilation into the herbivorous food web or sinking export. Based on particle interceptor traps and 234Th deficits, 27% of the particulate primary production (PP) sank out of the upper 50 m, with only 7% and 1% of PP reaching the benthos at shallow (≈200 m) and deep (≈500 m) sites, respectively. Mass balance calculations and grazing estimates agree that ≈79% of PP was ingested by pelagic consumers between April and July. During this period, the vertical flux of biogenic silica (BioSi) at 50 m was equivalent to the total BioSi produced, indicating that all of the diatom production was removed from the euphotic zone as intact cells (direct sinking) or empty frustules (grazing or lysis). The estimated flux of empty frustules was consistent with rates of herbivory by the large, dominant copepods and appendicularians during incubations. Since the carbon demand of the dominant planktivorous bird, Alle alle, amounted to ≈2% of the biomass synthesized by its main prey, the large copepod Calanus hyperboreus, most of the secondary carbon production was available to pelagic carnivores. Stable isotopes indicated that the biomass of predatory amphipods, polar cod and marine mammals was derived from these herbivores, but corresponding carbon fluxes were not quantified. Our analysis shows that a large fraction of PP in the eastern North Water was ingested by consumers in the upper 50 m, leading to substantial carbon respiration and DOC accumulation in surface waters. An increasingly early and prolonged opening of the Artic Ocean is likely to promote the productivity of the herbivorous food web, but not the short-term efficiency of the particulate, biological CO 2 pump.

  17. Nitrogen reduction pathways in estuarine sediments: Influences of organic carbon and sulfide

    Science.gov (United States)

    Plummer, Patrick; Tobias, Craig; Cady, David

    2015-10-01

    Potential rates of sediment denitrification, anaerobic ammonium oxidation (anammox), and dissimilatory nitrate reduction to ammonium (DNRA) were mapped across the entire Niantic River Estuary, CT, USA, at 100-200 m scale resolution consisting of 60 stations. On the estuary scale, denitrification accounted for ~ 90% of the nitrogen reduction, followed by DNRA and anammox. However, the relative importance of these reactions to each other was not evenly distributed through the estuary. A Nitrogen Retention Index (NIRI) was calculated from the rate data (DNRA/(denitrification + anammox)) as a metric to assess the relative amounts of reactive nitrogen being recycled versus retained in the sediments following reduction. The distribution of rates and accompanying sediment geochemical analytes suggested variable controls on specific reactions, and on the NIRI, depending on position in the estuary and that these controls were linked to organic carbon abundance, organic carbon source, and pore water sulfide concentration. The relationship between NIRI and organic carbon abundance was dependent on organic carbon source. Sulfide proved the single best predictor of NIRI, accounting for 44% of its observed variance throughout the whole estuary. We suggest that as a single metric, sulfide may have utility as a proxy for gauging the distribution of denitrification, anammox, and DNRA.

  18. Carbon Supported Polyaniline as Anode Catalyst: Pathway to Platinum-Free Fuel Cells

    CERN Document Server

    Zabrodskii, A G; Malyshkin, V G; Sapurina, I Y

    2006-01-01

    The effectiveness of carbon supported polyaniline as anode catalyst in a fuel cell (FC) with direct formic acid electrooxidation is experimentally demonstrated. A prototype FC with such a platinum-free composite anode exhibited a maximum room-temperature specific power of about 5 mW/cm2

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

    Digital Repository Service at National Institute of Oceanography (India)

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

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-03-07

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

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

    Directory of Open Access Journals (Sweden)

    Oliver Lehnert

    2014-12-01

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

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

    Institute of Scientific and Technical Information of China (English)

    Togtohyn; Chuluun; Dennis; Ojima

    2002-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

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

    2009-01-01

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

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

    Science.gov (United States)

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

    2016-01-15

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

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

    Directory of Open Access Journals (Sweden)

    Shu Guowei

    2016-06-01

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

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

    Science.gov (United States)

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

    2010-12-01

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

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

    Science.gov (United States)

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

    2004-01-01

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

  8. Arabidopsis lonely guy (LOG) multiple mutants reveal a central role of the LOG-dependent pathway in cytokinin activation.

    Science.gov (United States)

    Tokunaga, Hiroki; Kojima, Mikiko; Kuroha, Takeshi; Ishida, Takashi; Sugimoto, Keiko; Kiba, Takatoshi; Sakakibara, Hitoshi

    2012-01-01

    Cytokinins are phytohormones that play key roles in the maintenance of stem cell activity in plants. Although alternative single-step and two-step activation pathways for cytokinin have been proposed, the significance of the single-step pathway which is catalyzed by LONELY GUY (LOG), is not fully understood. We analyzed the metabolic flow of cytokinin activation in Arabidopsis log multiple mutants using stable isotope-labeled tracers and characterized the mutants' morphological and developmental phenotypes. In tracer experiments, cytokinin activation was inhibited most pronouncedly by log7, while the other log mutations had cumulative effects. Although sextuple or lower-order mutants did not show drastic phenotypes in vegetative growth, the log1log2log3log4log5log7log8 septuple T-DNA insertion mutant in which the LOG-dependent pathway is impaired, displayed severe retardation of shoot and root growth with defects in the maintenance of the apical meristems. Detailed observation of the mutants showed that LOG7 was required for the maintenance of shoot apical meristem size. LOG7 was also suggested to play a role for normal primary root growth together with LOG3 and LOG4. These results suggest a dominant role of the single-step activation pathway mediated by LOGs for cytokinin production, and overlapping but differentiated functions of the members of the LOG gene family in growth and development.

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

    Science.gov (United States)

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

    2015-06-01

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

  10. Carbon antisite clusters in SiC: a possible pathway to the D_{II} center

    OpenAIRE

    Mattausch, Alexander; Bockstedte, Michel; Pankratov, Oleg

    2003-01-01

    The photoluminescence center D_{II} is a persistent intrinsic defect which is common in all SiC polytypes. Its fingerprints are the characteristic phonon replicas in luminescence spectra. We perform ab-initio calculations of vibrational spectra for various defect complexes and find that carbon antisite clusters exhibit vibrational modes in the frequency range of the D_{II} spectrum. The clusters possess very high binding energies which guarantee their thermal stability--a known feature of the...

  11. Measurement of black carbon at Syowa station, Antarctica: seasonal variation, transport processes and pathways

    OpenAIRE

    Hara, K.; K. Osada; Yabuki, M.; Hayashi, M; Yamanouchi, T; Shiobara, M.; Wada, M.

    2008-01-01

    Measurement of black carbon (BC) was carried out at Syowa station Antarctica (69° S, 39° E) from February 2004 until January 2007. The BC concentration at Syowa ranged from below detection to 176 ng m−3 during the measurements. Higher BC concentrations were observed mostly under strong wind (blizzard) conditions due to the approach of a cyclone and blocking event. The BC-rich air masses traveled from the lower troposphere of the Atlantic and In...

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

    Science.gov (United States)

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

    2014-12-01

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

  13. 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

    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 will focus 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 amidase. The objective of the final phase of the project will be to develop derivative CN bond cleaving enzymes that have broader substrate ranges and to demonstrate the use of such strains to selectively remove nitrogen from petroleum. The project is on schedule and no major difficulties have been encountered. During the first year of the project (October, 2002-September, 2003) enrichment culture experiments have resulted in the isolation of promising cultures that may be capable of cleaving C-N bonds in aromatic amides, several amidase genes have been cloned and are currently undergoing directed evolution 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. Future research will address expression of these genes in Rhodococcus erythropolis. Enrichment culture experiments and directed evolution experiments continue to be a main focus of research activity and further work is required to obtain an appropriate amidase that will selectively cleave C-N bonds in aromatic substrates. Once an appropriate amidase gene is obtained it must be combined with genes encoding an enzyme capable of converting carbazole to 2'aminobiphenyl-2,3-diol: specifically carA genes. The carA genes from two sources have been cloned and are ready for construction of C-N bond cleavage

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

    Science.gov (United States)

    Koutsovitis, Petros; Magganas, Andreas; Economou, Georgios

    2016-04-01

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

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

    Science.gov (United States)

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

    2014-12-01

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

  16. Wnt Signaling Pathway in Central Nervous System Diseases%Wnt信号通路和中枢神经系统疾病的研究进展

    Institute of Scientific and Technical Information of China (English)

    马义辉(综述); 周杰; 荔志云(审校)

    2014-01-01

    Wnt信号通路作为多细胞真核生物中的重要信号通路,不仅参与神经干细胞的增殖、分化、轴突形成等过程,还调控突触发生、突触囊泡循环等生理过程。最近的研究还证实,Wnt信号通路在血管再生、血管重塑和血脑屏障的形成等生理过程中也发挥着重要作用。近年来的研究证实, Wnt信号通路在脑卒中、阿尔兹海默症和帕金森病等中枢神经系统疾病中发挥着重要的作用。因此,探讨Wnt信号通路与神经系统疾病的病理生理机制和治疗的关系有重要意义。%As an important pathway in multicellular eukaryotes,Wnt signaling pathway not only involves in the proliferation,differentiation and neurite formation process of neural stem cells,but also regulates synap-togenesis,synaptic vesicle recycling,and other physiological processes. Recent studies also confirm that,Wnt signaling pathway plays an important role in angiogenesis,vascular remodeling and formation of blood-brain barrier and other important physiological processes. Recent studies have demonstrated that Wnt signaling pathway plays an important role in stroke,Alzheimer's disease and Parkinson's disease and other central nerv-ous system diseases. So discussing the relationship of the Wnt signaling pathway with the neurological disor-ders’ pathogenesis and treatment has an important significance.

  17. Carbon Fluxes between Primary Metabolism and Phenolic Pathway in Plant Tissues under Stress

    Directory of Open Access Journals (Sweden)

    Sofia Caretto

    2015-11-01

    Full Text Available Higher plants synthesize an amazing diversity of phenolic secondary metabolites. Phenolics are defined secondary metabolites or natural products because, originally, they were considered not essential for plant growth and development. Plant phenolics, like other natural compounds, provide the plant with specific adaptations to changing environmental conditions and, therefore, they are essential for plant defense mechanisms. Plant defensive traits are costly for plants due to the energy drain from growth toward defensive metabolite production. Being limited with environmental resources, plants have to decide how allocate these resources to various competing functions. This decision brings about trade-offs, i.e., promoting some functions by neglecting others as an inverse relationship. Many studies have been carried out in order to link an evaluation of plant performance (in terms of growth rate with levels of defense-related metabolites. Available results suggest that environmental stresses and stress-induced phenolics could be linked by a transduction pathway that involves: (i the proline redox cycle; (ii the stimulated oxidative pentose phosphate pathway; and, in turn, (iii the reduced growth of plant tissues.

  18. 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.

  19. The anatomical pathways for antennal sensory information in the central nervous system of the cricket, Gryllus bimaculatus

    OpenAIRE

    Yoritsune, Atsushi; Aonuma, Hitoshi

    2012-01-01

    Antennae are one of the major organs to detect chemo- and mechanosensory cue in crickets. Little is known how crickets process and integrate different modality of information in the brain. We thus used a number of different anatomical techniques to gain an understanding of the neural pathways extending from the antennal sensory neurons up to centers in the brain. We identified seven antennal sensory tracts (assigned as T1–7) utilizing anterograde dye filling from the antennal nerve. Tracts T1...

  20. 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

  1. Multi-Walled Carbon Nanotubes Promote Cementoblast Differentiation and Mineralization through the TGF-β/Smad Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Lu Li

    2015-02-01

    Full Text Available Excretion of cementum by cementoblasts on the root surface is a process indispensable for the formation of a functional periodontal ligament. This study investigated whether carboxyl group-functionalized multi-walled carbon nanotubes (MWCNT-COOH could enhance differentiation and mineralization of mammalian cementoblasts (OCCM-30 and the possible signaling pathway involved in this process. Cementoblasts were incubated with various doses of MWCNT-COOH suspension. Cell viability was detected, and a scanning electron microscopy (SEM observed both the nanomaterials and the growth of cells cultured with the materials. Alizarin red staining was used to investigate the formation of calcium deposits. Real-time PCR and western blot were used to detect cementoblast differentiation and the underlying mechanisms through the expression of the osteogenic genes and the downstream effectors of the TGF-β/Smad signaling. The results showed that 5 µg/mL MWCNT-COOH had the most obvious effects on promoting differentiation without significant toxicity. Alp, Ocn, Bsp, Opn, Col1 and Runx2 gene expression was up-regulated. Smad2 and Smad3 mRNA was up-regulated, while Smad7 was first down-regulated on Day 3 and later up-regulated on Day 7. The elevated levels of phospho-Smad2/3 were also confirmed by western blot. In sum, the MWCNT-COOH promoted cementoblast differentiation and mineralization, at least partially, through interactions with the TGF-β/Smad pathway.

  2. Delayed Turnover of Unphosphorylated Ssk1 during Carbon Stress Activates the Yeast Hog1 Map Kinase Pathway.

    Directory of Open Access Journals (Sweden)

    Milene Carmes Vallejo

    Full Text Available In Saccharomyces cerevisiae, the Hog1 mitogen-activated protein kinase (MAPK pathway coordinates the adaptation to osmotic stress and was recently reported to respond to acute changes in glucose levels. Similarly as in osmotic stress, glucose starvation leads to a transient accumulation of Hog1 in the nucleus. However, the kinetics and the mechanism of Hog1 activation are different for these stress conditions. During osmotic shock the activation of Hog1 can be transduced by either the Sho1 or the Sln1/Ypd1/Ssk1 branch. During glucose starvation the phosphorylation of Hog1 is slower and is completely dependent on Ssk1, but independent of Sho1. To characterize the mechanism of activation of Hog1 during carbon stress, we examined the turnover of Ssk1 protein levels upon glucose starvation in the presence of cycloheximide and monitored protein levels by western blotting. Our data demonstrate that unphosphorylated Ssk1 was quickly degraded during exponential growth and after osmotic stress but remained remarkably stable during glucose limitation. We conclude that glucose starvation induces a delay in the turnover of unphosphorylated Ssk1, which is sufficient to activate the Hog1 MAPK pathway. Although unphosphorylated Ssk1 is known to be degraded by the proteasome, its stabilization is apparently not due to changes in cellular localization or decrease in ubiquitination levels during glucose limitation.

  3. Energy outlook to 2035 in Asia and its pathways towards a low carbon energy system

    Energy Technology Data Exchange (ETDEWEB)

    Komiyama, Ryoichi

    2010-09-15

    This report analyzes energy outlook in Asia and the world to 2035. In Technologically Advanced Scenario, advanced low-carbon technology yields, in 2035, 2,305 Mtoe or 14% of the saving in world primary energy demand and 12.3 Gt or 30% of the reduction in global CO2 emissions compared with the Reference Scenario. In these savings, Asia will account for 58% in the world primary energy reduction and 55% of the world CO2 mitigation, emphasizing immense potential of energy and CO2 saving in Asia and the importance of the deployment of clean energy technology through technology transfer to Asian region.

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

    Digital Repository Service at National Institute of Oceanography (India)

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

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

  5. System-based identification of toxicity pathways associated with multi-walled carbon nanotube-induced pathological responses

    Energy Technology Data Exchange (ETDEWEB)

    Snyder-Talkington, Brandi N. [Pathology and Physiology Research Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV 26505 (United States); Dymacek, Julian [Lane Department of Computer Science and Electrical Engineering, West Virginia University, Morgantown, WV 26506-6070 (United States); Mary Babb Randolph Cancer Center, West Virginia University, Morgantown, WV 26506-9300 (United States); Porter, Dale W.; Wolfarth, Michael G.; Mercer, Robert R. [Pathology and Physiology Research Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV 26505 (United States); Pacurari, Maricica [Mary Babb Randolph Cancer Center, West Virginia University, Morgantown, WV 26506-9300 (United States); Denvir, James [Department of Biochemistry and Microbiology, Marshall University, Huntington, WV 25755 (United States); Castranova, Vincent [Pathology and Physiology Research Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV 26505 (United States); Qian, Yong, E-mail: yaq2@cdc.gov [Pathology and Physiology Research Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV 26505 (United States); Guo, Nancy L., E-mail: lguo@hsc.wvu.edu [Mary Babb Randolph Cancer Center, West Virginia University, Morgantown, WV 26506-9300 (United States)

    2013-10-15

    The fibrous shape and biopersistence of multi-walled carbon nanotubes (MWCNT) have raised concern over their potential toxicity after pulmonary exposure. As in vivo exposure to MWCNT produced a transient inflammatory and progressive fibrotic response, this study sought to identify significant biological processes associated with lung inflammation and fibrosis pathology data, based upon whole genome mRNA expression, bronchoaveolar lavage scores, and morphometric analysis from C57BL/6J mice exposed by pharyngeal aspiration to 0, 10, 20, 40, or 80 μg MWCNT at 1, 7, 28, or 56 days post-exposure. Using a novel computational model employing non-negative matrix factorization and Monte Carlo Markov Chain simulation, significant biological processes with expression similar to MWCNT-induced lung inflammation and fibrosis pathology data in mice were identified. A subset of genes in these processes was determined to be functionally related to either fibrosis or inflammation by Ingenuity Pathway Analysis and was used to determine potential significant signaling cascades. Two genes determined to be functionally related to inflammation and fibrosis, vascular endothelial growth factor A (vegfa) and C-C motif chemokine 2 (ccl2), were confirmed by in vitro studies of mRNA and protein expression in small airway epithelial cells exposed to MWCNT as concordant with in vivo expression. This study identified that the novel computational model was sufficient to determine biological processes strongly associated with the pathology of lung inflammation and fibrosis and could identify potential toxicity signaling pathways and mechanisms of MWCNT exposure which could be used for future animal studies to support human risk assessment and intervention efforts. - Highlights: • A novel computational model identified toxicity pathways matching in vivo pathology. • Systematic identification of MWCNT-induced biological processes in mouse lungs • MWCNT-induced functional networks of lung

  6. System-based identification of toxicity pathways associated with multi-walled carbon nanotube-induced pathological responses

    International Nuclear Information System (INIS)

    The fibrous shape and biopersistence of multi-walled carbon nanotubes (MWCNT) have raised concern over their potential toxicity after pulmonary exposure. As in vivo exposure to MWCNT produced a transient inflammatory and progressive fibrotic response, this study sought to identify significant biological processes associated with lung inflammation and fibrosis pathology data, based upon whole genome mRNA expression, bronchoaveolar lavage scores, and morphometric analysis from C57BL/6J mice exposed by pharyngeal aspiration to 0, 10, 20, 40, or 80 μg MWCNT at 1, 7, 28, or 56 days post-exposure. Using a novel computational model employing non-negative matrix factorization and Monte Carlo Markov Chain simulation, significant biological processes with expression similar to MWCNT-induced lung inflammation and fibrosis pathology data in mice were identified. A subset of genes in these processes was determined to be functionally related to either fibrosis or inflammation by Ingenuity Pathway Analysis and was used to determine potential significant signaling cascades. Two genes determined to be functionally related to inflammation and fibrosis, vascular endothelial growth factor A (vegfa) and C-C motif chemokine 2 (ccl2), were confirmed by in vitro studies of mRNA and protein expression in small airway epithelial cells exposed to MWCNT as concordant with in vivo expression. This study identified that the novel computational model was sufficient to determine biological processes strongly associated with the pathology of lung inflammation and fibrosis and could identify potential toxicity signaling pathways and mechanisms of MWCNT exposure which could be used for future animal studies to support human risk assessment and intervention efforts. - Highlights: • A novel computational model identified toxicity pathways matching in vivo pathology. • Systematic identification of MWCNT-induced biological processes in mouse lungs • MWCNT-induced functional networks of lung

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

    Science.gov (United States)

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

    2015-10-01

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

  8. Pathway analysis using (13) C-glycerol and other carbon tracers reveals a bipartite metabolism of Legionella pneumophila.

    Science.gov (United States)

    Häuslein, Ina; Manske, Christian; Goebel, Werner; Eisenreich, Wolfgang; Hilbi, Hubert

    2016-04-01

    Amino acids represent the prime carbon and energy source for Legionella pneumophila, a facultative intracellular pathogen, which can cause a life-threatening pneumonia termed Legionnaires' disease. Genome, transcriptome and proteome studies indicate that L. pneumophila also utilizes carbon substrates other than amino acids. We show here that glycerol promotes intracellular replication of L. pneumophila in amoeba or macrophages (but not extracellular growth) dependent on glycerol-3-phosphate dehydrogenase, GlpD. An L. pneumophila mutant strain lacking glpD was outcompeted by wild-type bacteria upon co-infection of amoeba, indicating an important role of glycerol during infection. Isotopologue profiling studies using (13) C-labelled substrates were performed in a novel minimal defined medium, MDM, comprising essential amino acids, proline and phenylalanine. In MDM, L. pneumophila utilized (13) C-labelled glycerol or glucose predominantly for gluconeogenesis and the pentose phosphate pathway, while the amino acid serine was used for energy generation via the citrate cycle. Similar results were obtained for L. pneumophila growing intracellularly in amoeba fed with (13) C-labelled glycerol, glucose or serine. Collectively, these results reveal a bipartite metabolism of L. pneumophila, where glycerol and carbohydrates like glucose are mainly fed into anabolic processes, while serine serves as major energy supply. PMID:26691313

  9. Transcript level coordination of carbon pathways during silicon starvation-induced lipid accumulation in the diatom Thalassiosira pseudonana.

    Science.gov (United States)

    Smith, Sarah R; Glé, Corine; Abbriano, Raffaela M; Traller, Jesse C; Davis, Aubrey; Trentacoste, Emily; Vernet, Maria; Allen, Andrew E; Hildebrand, Mark

    2016-05-01

    Diatoms are one of the most productive and successful photosynthetic taxa on Earth and possess attributes such as rapid growth rates and production of lipids, making them candidate sources of renewable fuels. Despite their significance, few details of the mechanisms used to regulate growth and carbon metabolism are currently known, hindering metabolic engineering approaches to enhance productivity. To characterize the transcript level component of metabolic regulation, genome-wide changes in transcript abundance were documented in the model diatom Thalassiosira pseudonana on a time-course of silicon starvation. Growth, cell cycle progression, chloroplast replication, fatty acid composition, pigmentation, and photosynthetic parameters were characterized alongside lipid accumulation. Extensive coordination of large suites of genes was observed, highlighting the existence of clusters of coregulated genes as a key feature of global gene regulation in T. pseudonana. The identity of key enzymes for carbon metabolic pathway inputs (photosynthesis) and outputs (growth and storage) reveals these clusters are organized to synchronize these processes. Coordinated transcript level responses to silicon starvation are probably driven by signals linked to cell cycle progression and shifts in photophysiology. A mechanistic understanding of how this is accomplished will aid efforts to engineer metabolism for development of algal-derived biofuels.

  10. IFN-γ inhibits central nervous system myelination through both STAT1-dependent and STAT1-independent pathways

    OpenAIRE

    Lin, Wensheng; Lin, Yifeng

    2010-01-01

    Immune cytokine interferon-γ (IFN-γ) plays a crucial role in immune-mediated demyelination diseases such as multiple sclerosis and experimental autoimmune encephalomyelitis (EAE). Our previous studies have shown that enforced expression of IFN-γ in the central nervous system (CNS) inhibits developmental myelination or remyelination in EAE demyelinated lesions. While many of the cellular actions of IFN-γ result from its activation of the signal transducer and activator of transcription 1 (STAT...

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

    Directory of Open Access Journals (Sweden)

    Sayed-Rzgar Hosseini

    2015-08-01

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

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

    Science.gov (United States)

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

    2015-12-01

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

  13. 犬尿氨酸代谢通路与中枢神经系统%The Kynurenine Metabolic Pathway and the Central Nervous System

    Institute of Scientific and Technical Information of China (English)

    李宁宁; 高平进

    2008-01-01

    The kynurenine metabolic pathway involves in a cascade of enzyme reaction generated multiple biologically-active compounds.These metabolites are called"kynurenines" which participate in diverse pathophysiological processes,particularly in the central nervous system.The kynurenines have important physiological functions.For example.quinolinic acid is an Nmethyl-D-aspartate(NMDA)receptor agonist.and it can be largely accumulated in the central nervous system in many infectious nervous system diseases,resulting in neuronal excitotoxicity and death.Kynurenic acid antagonizes excitatory glutamate receptors to reduce excitotoxicityinduced neuronal death.This article reviews the related researches of the effects of kynurenine metabolic pathway on the central nervous system.%犬尿氨酸代谢通路涉及一系列酶促反应,生成多种具有生物学活性的化合物,这些代谢产物统称为"犬尿氨酸能物质".犬尿氨酸能物质参与多种病理生理学过程,在中枢神经系统中有着重要的生理功能.例如,喹咻酸是N-甲基-D-天冬氨酸受体激动剂,在许多感染性神经系统疾病中可大量堆积在中枢神经系统,导致神经元因兴奋性中毒而死亡.犬尿喹啉酸可拮抗兴奋性谷氨酸盐受体,减少因兴奋性中毒导致的神经元死亡.文章就犬尿氨酸代谢通路在中枢神经系统中作用的相关研究做了综述.

  14. Assessing “gas transition” pathways to low carbon electricity – An Australian case study

    International Nuclear Information System (INIS)

    Highlights: • High gas electricity portfolios are higher cost and risk compared with renewables. • High gas portfolios do not achieve required greenhouse gas emissions reductions. • Optimal portfolios are 60% renewables by 2030 and 80–100% by 2050. • Firm capacity is provided by coal-fired plant in a peaking role rather than gas. - Abstract: Future generation portfolios including varying quantities of gas-fired and renewable generation were compared on the basis of expected costs, cost risk and greenhouse gas emissions, with a view to understanding the merits and disadvantages of gas and renewable technologies. A Monte-Carlo based generation portfolio modelling tool was applied to take into account the effects of highly uncertain future gas prices, carbon pricing policy and electricity demand. Results suggest that portfolios sourcing significant quantities of energy from gas-fired generation in 2030 and 2050 are likely to be significantly higher cost and significantly higher risk than the other alternatives considered. High gas portfolios also do not achieve the greenhouse gas (GHG) emissions reductions levels that appear required to avoid dangerous global warming. For example, portfolios that source 95% of energy from gas-fired generation in 2050 experience expected generation costs that are $65/MW h (40%) higher than portfolios that source only 20% of energy from gas-fired generation. These high gas portfolios also exhibit a cost risk (standard deviation in cost) that is three times higher. The lowest cost portfolios in 2050 source less than 20% of energy from gas with the remaining energy sourced from renewables. Even in the absence of a carbon price, the lowest cost portfolio in 2050 sources only 30% of energy from gas-fired generation, with the remaining 70% of energy being sourced from renewable technologies. Results suggest the optimal strategy for minimising costs, minimising cost risk and reducing GHG emission levels in future electricity

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

    Science.gov (United States)

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

    2014-07-01

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

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2016-03-01

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

  18. Single-walled carbon nanotubes as nano-electrode and nano-reactor to control the pathways of a redox reaction.

    Science.gov (United States)

    McSweeney, Robert L; Chamberlain, Thomas W; Davies, E Stephen; Khlobystov, Andrei N

    2014-11-28

    Single-walled carbon nanotubes have been demonstrated as effective nanoscale containers for a redox active organometallic complex Cp(Me)Mn(CO)3, acting simultaneously as nano-electrode and nano-reactor. Extreme spatial confinement of the redox reaction within the nanotubes changes its pathway compared to bulk solution due to stabilisation of a reactive intermediate.

  19. Carbon mineralization in Arctic sediments northeast of Svalbard: Mn(IV) and Fe(III) reduction as principal anaerobic respiratory pathways

    DEFF Research Database (Denmark)

    Vandieken, Verona; Nickel, Maren; Jørgensen, Bo Barker

    2006-01-01

    Carbon oxidation rates and pathways were determined in 3 sediments at latitude 79 degrees to 81 degrees N in the Barents Sea, where the ice cover restricts primary production to a few months of the year. Oxygen uptake (1.5 to 3.5 imnol m(-2) d(-1)) and sulfate reduction (= 60 mu mol cm(-3)) and F...

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

    Directory of Open Access Journals (Sweden)

    K. Kawamura

    2012-01-01

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

  1. Osteosarcoma of the lumbosacral spine invading the central venous pathways, right-sided cardiac chambers, and pulmonary artery

    Energy Technology Data Exchange (ETDEWEB)

    Hines, Neely; Lantos, George; Hochzstein, Jay [Jacobi Medical Center/Albert Einstein College of Medicine, Department of Radiology, Bronx, NY (United States); Gitig, Alon [Montefiore Medical Center/Albert Einstein College of Medicine, Department of Cardiology, Bronx, NY (United States); DeAnda, Abe [Montefiore Medical Center/Albert Einstein College of Medicine, Department of Cardiothoracic Surgery, Bronx, NY (United States)

    2007-11-15

    We report an unusual case of lumbosacral osteogenic sarcoma with cauda equina syndrome and invasion into the central venous and cardiac system. A 41-year-old Hispanic man presented to the emergency department complaining of severe low back pain, cauda equina syndrome, bilateral lower extremity edema, and an extra heart sound on physical examination. CT of the lumbosacral spine done in the emergency department demonstrated a sclerotic lesion in the sacrum with cortical destruction, extension into the spinal canal and a bulky soft tissue mass containing calcifications. Supplemental MRI demonstrated marrow replacement of L4, L5, and the sacrum, soft tissue extension of the tumor, and invasion iliac veins extending into the IVC; however, the full extent of the intravascular tumor was not seen on this examination. Surgical laminectomy and biopsy of the spinal tumor provided the diagnosis of osteogenic sarcoma. A transthoracic echocardiogram was performed while the patient was recovering due to nonsustained ventricular tachycardia, which showed an echogenic mass within the right atrium and ventricle. CT pulmonary angiogram confirmed the echocardiogram showing a tumor extending through the pulmonary valve into the main pulmonary artery. The patient underwent en bloc resection of the tumor from the venous and cardiac systems. Histologic examination of the tumor confirmed osteogenic sarcoma. While vertebral osteogenic sarcoma is uncommon, invasion of the spinal canal is common in these tumors. However, tumor extending into the central venous and cardiac system is rare. The previously reported cases of central venous and cardiac involvement have been related to distant metastases or primary cardiac osteosarcomas. There is only one other reported case of direct extension into the venous system by an iliac bone osteosarcoma in an adolescent; however, the tumor did not extend into the pulmonary circulation. (orig.)

  2. Growth, biomass, carbon storage and nutrient distribution in Gmelina arborea Roxb. stands on red lateritic soils in central India.

    Science.gov (United States)

    Swamy, S L; Puri, S; Singh, A K

    2003-11-01

    Growth, biomass, carbon storage and nutrient (N, P and K) variations in 1 to 6-year-old chronosequence plantations of Gmelina arborea were studied in three degraded red lateritic sites in central India. Growth parameters (dbh, total height and number of branches) varied significantly due to difference in age and site quality, but tree density showed non-significant variation. Stand biomass ranged from 3.94 (1-year-old) to 53.67 Mgha(-1) (6-year-old) and stand carbon in 6-year-old plantations ranged from 24.12 to 31.12 Mgha(-1) at different sites. Among the tree components, the stem wood accounted for maximum C (56.25% at site 1) followed by branches (19.8% at site 3), roots (18.51% at site 2) and foliage (7.01% at site 3). Mean annual C accretion at 6 years age of plantation was highest in site 3 and it was 0.35, 2.66, 0.965 and 0.87 Mgha(-1) for leaf, stem, branches and roots, respectively. Quantity of nutrients increased with age. Total nitrogen accumulation in 6-year-old stands at the three sites ranged from 212.9 to 279.5 kgha(-1) with a mean annual storage of 238.43 kgha(-1) and total K ranged from 170.8 to 220.5 kgha(-1) with a mean annual storage of 189.93 kgha(-1). Phosphorous accumulation was lowest with a mean storage of 16.75 kgha(-1). The organic carbon and nutrients in the soils improved significantly after 6 years of G. arborea planting. Soil organic carbon increased from 8.46 to 14.02 Mgha(-1) within 6 years. At soil depths 0-20 cm, 21-40 cm and 41-60 cm, available N enhanced by 14.85%, 11.98% and 11.25%, K by 10%, 9.13% and 10.63%, whereas phosphorous declined by 26%, 23% and 20%, respectively. At 6 years, G. arborea stands sequestered 31.37 Mgha(-1) carbon. The nutrient management strategies in relation to carbon accretion in G. arborea stands on degraded lateritic sites are discussed. PMID:12895553

  3. Dynamics of seawater carbonate chemistry, production, and calcification of a coral reef flat, central Great Barrier Reef

    Directory of Open Access Journals (Sweden)

    R. Albright

    2013-10-01

    Full Text Available Ocean acidification is projected to shift coral reefs from a state of net accretion to one of net dissolution this century. Presently, our ability to predict global-scale changes to coral reef calcification is limited by insufficient data relating seawater carbonate chemistry parameters to in situ rates of reef calcification. Here, we investigate diel and seasonal trends in carbonate chemistry of the Davies Reef flat in the central Great Barrier Reef and relate these trends to benthic carbon fluxes by quantifying net ecosystem calcification (nec and net community production (ncp. Results show that seawater carbonate chemistry of the Davies Reef flat is highly variable over both diel and seasonal cycles. pH (total scale ranged from 7.92 to 8.17, pCO2 ranged from 272 to 542 μatm, and aragonite saturation state (Ωarag ranged from 2.9 to 4.1. Diel cycles in carbonate chemistry were primarily driven by ncp, and warming explained 35% and 47% of the seasonal shifts in pCO2 and pH, respectively. Daytime ncp averaged 37 ± 19 mmol C m−2 h−1 in summer and 33 ± 13 mmol C m−2 h−1 in winter; nighttime ncp averaged −30 ± 25 and −7 ± 6 mmol C m−2 h−1 in summer and winter, respectively. Daytime nec averaged 11 ± 4 mmol CaCO3 m−2 h−1 in summer and 8 ± 3 mmol CaCO3 m−2 h−1 in winter, whereas nighttime nec averaged 2 ± 4 mmol and −1 ± 3 mmol CaCO3 m−2 h−1 in summer and winter, respectively. Net ecosystem calcification was highly sensitive to changes in Ωarag for both seasons, indicating that relatively small shifts in Ωarag may drive measurable shifts in calcification rates, and hence carbon budgets, of coral reefs throughout the year.

  4. Carbonate cementation as related to the diagenesis of clay in a mixed siliciclastic-carbonate system: Examples from the Centerfield biostrome, east central Pennsylvania

    Energy Technology Data Exchange (ETDEWEB)

    Burns, C.D. (Univ. of North Carolina, Chapel Hill, NC (United States))

    1994-03-01

    The Middle Devonian Mahantango Formation consists of siliciclastic and mixed carbonate-siliciclastic sediment packages that pulse in and out of the stratigraphy. The formation crops out in several places throughout the folded rocks of eastern Pennsylvania and Maryland. The Centerfield Member is one of the mixed siliciclastic-carbonate packages in the Mahantango Fm. This member crops out in east central Pennsylvania. The Centerfield Mbr. has been interpreted as a series of biostromes and contain abundant rugosan corals, crinoids, bryozoans, and brachiopods. The biostromes have undergone a complex diagenetic history. Illite, smectite, chlorite and muscovite have been found with the use of powder x-ray diffraction and petrographic analysis. The smectite and some of the illite are depositional clays, while, the remaining illite, chlorite and muscovite represent recrystallization of the depositional clays. There are six phases of cement in the biostrome. The paragenetic sequence of the cements is as follows: non-ferroan low magnesian calcite (LMC), intermediate ferroan LMC, ferroan LMC, non-ferroan dolomite, ferroan baroque dolomite, and quartz cement in the form of chert and blocky cement. Staining shows that the iron content of the cement changes within individual crystals and between cement phases. Preliminary data suggest that the cements may be directly related to the steady release of ions during the diagenesis of the surrounding clays in the shale.

  5. Liquiritigenin Protects Rats from Carbon Tetrachloride Induced Hepatic Injury through PGC-1α Pathway

    Directory of Open Access Journals (Sweden)

    Yiping Zhang

    2015-01-01

    Full Text Available The lack of effective treatment for liver cirrhosis and hepatocellular carcinomas imposes serious challenges to the healthcare system. Here, we investigated the efficacy and mechanism of liquiritigenin involved in preventing or retarding the progression of liver diseases in a rat model with chronic carbon tetrachloride (CCl4 exposure. Sprague Dawley rats were given CCl4 and lliquiritigenin alone or simultaneously for 8 weeks before liver was harvested to check histological changes by Hematoxylin and Eosin (H&E staining, apoptosis by TUNEL assay, ROS by dihydroethidium staining, antioxidant enzyme activities and malondialdehyde using specific kits, and gene expression by quantitative real-time PCR and western blot. Chronic CCl4 exposure caused profound changes in liver histology with extensive hepatocyte death (necrosis and apoptosis, fat accumulation, and infiltration of inflammatory cells, accompanied by depressed activities of antioxidant enzymes, increased oxidative stress, elevated expression of inflammation and fibrotic genes, and downregulation of PGC-1α, ND1, and Bcl-x in rat liver. All these changes were abolished or alleviated by lliquiritigenin. The results demonstrated that liquiritigenin is effective in protecting liver from injury or treating chronic liver diseases. The modulation of PGC-1α and its downstream genes might play a critical role in relieving CCl4-induced hepatic pathogenesis by liquiritigenin.

  6. Nitric oxide modulates hypoxic pulmonary smooth muscle cell proliferation and apoptosis by regulating carbon monoxide pathway

    Institute of Scientific and Technical Information of China (English)

    Yan-fei WANG; Hong TIAN; Chao-shu TANG; Hong-fang JIN; Jun-bao DU

    2007-01-01

    Aim: To explore the role of carbon monoxide (CO) in the regulation of hypoxic pulmonary artery smooth muscle cell (PASMC) proliferation and apoptosis by nitric oxide (NO). Methods: PASMC of Wistar rats was cultured in vitro in the presence of a NO donor, sodium nitroprusside, or an inhibitor of heme oxygenase (HO), zinc protoporphyrin-IX, or under both normoxic and hypoxic conditions.Nitrite and carboxyhemoglobin in PASMC medium were detected with spectrophotometry. The proliferating and apoptotic percentage of PASMC was measured by flow cytometry. The expression of HO-1 mRNA in PASMC was analyzed by fluorescent real-time quantitative PCR, and the proliferating cell nuclear antigen and caspase-3 were examined by immunocytochemical analysis. Results: The results showed that hypoxia suppressed NO generation from PASMC, which promoted hypoxic PASMC proliferation and induced apoptosis. Meanwhile, hy-poxia induced HO-1 expression in PASMC and promoted CO production from PASMC, which inhibited PASMC proliferation and regulated PASMC apoptosis. NO upregulated the expression of HO-1 mRNA in hypoxic PASMC; NO also inhib-ited proliferation and promoted apoptosis of hypoxic PASMC, possibly by regu-lating the production of CO. Conclusion: The results indicated that CO could inhibit proliferation and regulate apoptosis of PASMC, and NO inhibited prolifera-tion and promoted apoptosis of hypoxic PASMC, possibly by regulating the pro-duction of CO.

  7. Carbon budget in the eastern and central Arabian Sea: An Indian JGOFS synthesis

    Digital Repository Service at National Institute of Oceanography (India)

    Sarma, V.V.S.S.; Swathi, P.S.; DileepKumar, M.; PrasannaKumar, S.; Bhattathiri, P.M.A.; Madhupratap, M.; Ramaswamy, V.; Sarin, M.M.; Gauns, M.; Ramaiah, N.; Sardessai, S.; DeSousa, S.N.

    of its unique monsoon-driven, dynamic, and complex biogeochemistry. The JGOFS (India) I HydfOsphcric-!\\tlllosphcri<: Research Center. Nagoya University, Nagoya, Japan. 2CS1R Centre ti.1r 'Aathcmutical 'Aodeling and Computer Simulation, Banr,alore-: India.... Our assumption is supported by small variability in TOC observed in U.S.-JGOFS [Hal/sell and Pellcer, 199RJ. We believe that the uncertainties associated with the considered constancy of TOe would not affect final trends in carbon TCO,~297S.9 - 19.9T...

  8. Recent mantle degassing recorded by carbonic spring deposits along sinistral strike-slip faults, south-central Australia

    Science.gov (United States)

    Ring, Uwe; Tonguç Uysal, I.; Yüce, Galip; Ünal-İmer, Ezgi; Italiano, Francesco; İmer, Ali; Zhao, Jian-xin

    2016-11-01

    The interior of the Australian continent shows evidence for late Quaternary to Recent fault-controlled mantle 3He and CO2 degassing. A series of interconnected NW-striking sinistral faults, the Norwest fault zone (NFZ), in south-central Australia are associated with travertine mounds, the latter show a regular spacing of 50-70 km. U-series ages on 26 samples range from 354 ± 7 to 1.19 ± 0.02ka (2σ errors) and suggest a clustering every ∼3-4 ka since ∼26 ka. Geochemical data demonstrate a remarkable mantle-to-groundwater connection. Isotopic data indicate that the groundwater is circulating to depths >3 km and interacting with Neoproterozoic/Cambrian basement and mantle volatiles. 3He/4He isotope ratios show that the He comes in part from the mantle. This demonstrates that the NFZ cuts through the entire crust and provides pathways for mantle degassing. Scaling relationships suggest that the series of sinistral faults that make up the NFZ are interconnected at depths and have a significant strike length of 60-70 km or more. The NFZ occurs where a major compositional boundary and a significant heat flow anomaly occurs, and a major step in lithospheric thickness has been mapped. We discuss a tectonic model in which recent stress field, heat flow and lithospheric structure in central Australia reactivated a set of steeply dipping Neoproterozoic faults, which may now be growing into a crustal/lithospheric-scale structure.

  9. Assessment of GHG emission reduction pathways in a society without carbon capture and nuclear technologies

    International Nuclear Information System (INIS)

    Every possible technology is pursued in order to achieve strict radiative forcing targets. Nuclear energy and Carbon Capture Storage (CCS) are regarded as important mitigation options. However, harsh criticisms have been directed at Japanese nuclear energy policy after the Fukushima nuclear accident, and the Japanese government will be required to re-evaluate not only its energy policy, but also the GHG reduction target itself. Like nuclear energy, CCS might not be regarded as a suitable option for GHG mitigation because its long-term safety has not been revealed. In this paper we analyze the energy policy response to an absence of nuclear energy and CCS, especially focusing on Japan, China and India. We find that the appropriate energy strategies against the unproven technologies differ between regions due to the uneven pre-existing nuclear energy, CCS potential and renewable energy potential, and the resource endowments and the levels of economic development. We also find that the strict mitigation target can be achieved even if nuclear energy and CCS are not available. In such a case, however, significant enhancement of renewable energy is needed, as well as particular fossil fuel alternatives based on region-specific availabilities and costs. - Highlights: ► We used a recursive-dynamic CGE model in which many advanced technologies are considered. ► We simulated radiative forcing targets assuming no availability of nuclear and CCS. ► The appropriate energy strategies against the unproven technologies differ between regions. ► The significant enhancement of renewable energy is needed, as well as particular fossil fuel alternatives.

  10. Carbon monoxide alleviates ethanol-induced oxidative damage and inflammatory stress through activating p38 MAPK pathway

    International Nuclear Information System (INIS)

    Stress-inducible protein heme oxygenase-1(HO-1) is well-appreciative to counteract oxidative damage and inflammatory stress involving the pathogenesis of alcoholic liver diseases (ALD). The potential role and signaling pathways of HO-1 metabolite carbon monoxide (CO), however, still remained unclear. To explore the precise mechanisms, ethanol-dosed adult male Balb/c mice (5.0 g/kg.bw.) or ethanol-incubated primary rat hepatocytes (100 mmol/L) were pretreated by tricarbonyldichlororuthenium (II) dimmer (CORM-2, 8 mg/kg for mice or 20 μmol/L for hepatocytes), as well as other pharmacological reagents. Our data showed that CO released from HO-1 induction by quercetin prevented ethanol-derived oxidative injury, which was abolished by CO scavenger hemoglobin. The protection was mimicked by CORM-2 with the attenuation of GSH depletion, SOD inactivation, MDA overproduction, and the leakage of AST, ALT or LDH in serum and culture medium induced by ethanol. Moreover, CORM-2 injection or incubation stimulated p38 phosphorylation and suppressed abnormal Tnfa and IL-6, accompanying the alleviation of redox imbalance induced by ethanol and aggravated by inflammatory factors. The protective role of CORM-2 was abolished by SB203580 (p38 inhibitor) but not by PD98059 (ERK inhibitor) or SP600125 (JNK inhibitor). Thus, HO-1 released CO prevented ethanol-elicited hepatic oxidative damage and inflammatory stress through activating p38 MAPK pathway, suggesting a potential therapeutic role of gaseous signal molecule on ALD induced by naturally occurring phytochemicals. - Highlights: • CO alleviated ethanol-derived liver oxidative and inflammatory stress in mice. • CO eased ethanol and inflammatory factor-induced oxidative damage in hepatocytes. • The p38 MAPK is a key signaling mechanism for the protective function of CO in ALD

  11. Carbon monoxide alleviates ethanol-induced oxidative damage and inflammatory stress through activating p38 MAPK pathway

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yanyan; Gao, Chao; Shi, Yanru; Tang, Yuhan; Liu, Liang; Xiong, Ting; Du, Min [Department of Nutrition and Food Hygiene, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan 430030 (China); Ministry of Education Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan 430030 (China); Hubei Key Laboratory of Food Nutrition and Safety, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan 430030 (China); Xing, Mingyou [Department of Infectious Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan 430030 (China); Liu, Liegang [Department of Nutrition and Food Hygiene, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan 430030 (China); Ministry of Education Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan 430030 (China); Hubei Key Laboratory of Food Nutrition and Safety, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan 430030 (China); Yao, Ping, E-mail: yaoping@mails.tjmu.edu.cn [Department of Nutrition and Food Hygiene, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan 430030 (China); Ministry of Education Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan 430030 (China); Hubei Key Laboratory of Food Nutrition and Safety, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan 430030 (China)

    2013-11-15

    Stress-inducible protein heme oxygenase-1(HO-1) is well-appreciative to counteract oxidative damage and inflammatory stress involving the pathogenesis of alcoholic liver diseases (ALD). The potential role and signaling pathways of HO-1 metabolite carbon monoxide (CO), however, still remained unclear. To explore the precise mechanisms, ethanol-dosed adult male Balb/c mice (5.0 g/kg.bw.) or ethanol-incubated primary rat hepatocytes (100 mmol/L) were pretreated by tricarbonyldichlororuthenium (II) dimmer (CORM-2, 8 mg/kg for mice or 20 μmol/L for hepatocytes), as well as other pharmacological reagents. Our data showed that CO released from HO-1 induction by quercetin prevented ethanol-derived oxidative injury, which was abolished by CO scavenger hemoglobin. The protection was mimicked by CORM-2 with the attenuation of GSH depletion, SOD inactivation, MDA overproduction, and the leakage of AST, ALT or LDH in serum and culture medium induced by ethanol. Moreover, CORM-2 injection or incubation stimulated p38 phosphorylation and suppressed abnormal Tnfa and IL-6, accompanying the alleviation of redox imbalance induced by ethanol and aggravated by inflammatory factors. The protective role of CORM-2 was abolished by SB203580 (p38 inhibitor) but not by PD98059 (ERK inhibitor) or SP600125 (JNK inhibitor). Thus, HO-1 released CO prevented ethanol-elicited hepatic oxidative damage and inflammatory stress through activating p38 MAPK pathway, suggesting a potential therapeutic role of gaseous signal molecule on ALD induced by naturally occurring phytochemicals. - Highlights: • CO alleviated ethanol-derived liver oxidative and inflammatory stress in mice. • CO eased ethanol and inflammatory factor-induced oxidative damage in hepatocytes. • The p38 MAPK is a key signaling mechanism for the protective function of CO in ALD.

  12. Aphotic zone carbonate production on a Miocene ramp, Central Apennines, Italy

    Science.gov (United States)

    Corda, Laura; Brandano, Marco

    2003-09-01

    The lower Miocene Latium-Abruzzi platform was a low-angle ramp that developed under tropical-to-subtropical conditions, but was dominated by bryomol and rhodalgal sediment associations. The Aquitanian to Serravallian sequence described here paraconformably overlies the Cretaceous limestones. It consists of a lowstand systems tract, a transgressive systems tract and a highstand systems tract. Based on facies analysis and on the light dependence of biotic associations, the ramp is divided into three parts: an inner ramp, a middle ramp and an outer ramp. The inner ramp facies are represented by a few metres of coral framestone, rhodolith floatstone-rudstone and balanid macroids floatstone without wave-related structures. The middle ramp consists of structureless bioclastic grainstone to packstone, floatstone and rudstone with rhodoliths and larger foraminifera. The outer ramp facies—proximal sector—are composed of crudely stratified bryozoan-dominated packstone to floatstone which extend over the whole platform. The outer ramp facies—intermediate sector—are represented by wackestone, packstone and rarely grainstone with foraminifera and echinoid fragments. The final depositional profile of the ramp was strongly influenced by the main organisms producing sediment. During the lowstand, the resulting profile is a ramp type. During the transgressive phase, the rapid spreading of the outer ramp facies belt, as a consequence of the enhanced productivity of the light-independent biota, is believed to be promoted by a change from oligotrophic to eutrophic conditions. Climate and/or tectonics are presumed to have played an important role in continental runoff and then in the nutrients delivery. During the highstand phase, the system returns to rates of production uniform throughout the platform. The high rates of carbonate production occurring in the aphotic zone are quite unusual in tropical settings and represent a provocative trend in apparent contrast with the

  13. Effect of Direct Seeding Mulch-Based Systems on Soil Carbon Storage and Macrofauna in Central Brazil

    Directory of Open Access Journals (Sweden)

    Eric Blanchart

    2007-03-01

    Full Text Available Soils represent a large carbon pool, approximately 1500 Gt, equivalent to almost three times the quantity stored in terrestrial biomass and twice the amount stored in the atmosphere. Any modification of land-use or land management can induce variations in soil carbon stocks, even in agricultural systems that are perceived to be in a steady state. These modifications also alter soil macrofauna that is known to affect soil carbon dynamics. Direct seeding Mulch-based Cropping (DMC systems with two crops per year without soil tillage have widely been adopted over the last 10 to 15 years in the Cerrado (central region of Brazil. They are replacing the traditional soybean monocropping with fallow under conventional tillage (CT. The objective of this study was to examine how DMC practices affect soil organic carbon (SOC dynamics and macrofauna (Rio Verde, Goias State. The approach was to determine soil C stocks and macrofauna in five fields under DMC aged 1, 5, 7, 11 and 13 years. In order to compare DMC systems with the native system of the region and previous land-use, a situation under native Cerrado (tree-savanna like vegetation and a field conducted traditionally (CT were also studied. Soil C stocks were calculated for the 0-10 and 0-40 cm soil depth and also for the first 400 kg m-2 of soil to compare the same amount of soil and to suppress the potential artefact of soil compaction when sample is based on fix layer depth. Soil macrofauna was hand-sorted from soil monoliths (30 cm depth, TSBF method. In our study, the annual rate of carbon storage was equal to ca. 1.6 MgC ha-1, which is in the range of values measured for DMC in different areas of Brazil, i.e., 0.4 to 1.7 MgC ha-1 with the highest rates obtained in the Cerrado region. Compared to natural vegetation, soil macrofauna in cropped systems was strongly modified. In CT, biomass and density were very low and much lower than in DMC systems. With increasing age of DMC, total macrofauna

  14. Dynamics of seawater carbonate chemistry, production, and calcification of a coral reef flat, Central Great Barrier Reef

    Directory of Open Access Journals (Sweden)

    R. Albright

    2013-05-01

    Full Text Available Ocean acidification is projected to shift coral reefs from a state of net accretion to one of net dissolution this century. Presently, our ability to predict global-scale changes to coral reef calcification is limited by insufficient data relating seawater carbonate chemistry parameters to in situ rates of reef calcification. Here, we investigate natural trends in carbonate chemistry of the Davies Reef flat in the central Great Barrier Reef on diel and seasonal timescales and relate these trends to benthic carbon fluxes by quantifying net ecosystem calcification (nec and net community production (ncp. Results show that seawater carbonate chemistry of the Davies Reef flat is highly variable over both diel and seasonal timescales. pH (total scale ranged from 7.92 to 8.17, pCO2 ranged from 272 to 542 μatm, and aragonite saturation state (Ωarag ranged from 2.9 to 4.1. Diel cycles in carbonate chemistry were primarily driven by ncp, and warming explained 35% and 47% of the seasonal shifts in pCO2 and pH, respectively. Daytime ncp averaged 36 ± 19 mmol C m−2 h−1 in summer and 33 ± 13 mmol C m−2 h−1 in winter; nighttime ncp averaged −22 ± 20 and −7 ± 6 mmol C m−2 h−1 in summer and winter, respectively. Daytime nec averaged 11 ± 4 mmol CaCO3 m−2 h−1 in summer and 8 ± 3 mmol CaCO3 m−2 h−1 in winter, whereas nighttime nec averaged 2 ± 4 mmol and −1 ± 3 mmol CaCO3 m−2 h−1 in summer and winter, respectively. Net ecosystem calcification was positively correlated with Ωarag for both seasons. Linear correlations of nec and Ωarag indicate that the Davies Reef flat may transition from a state of net calcification to net dissolution at Ωarag values of 3.4 in summer and 3.2 in winter. Diel trends in Ωarag indicate that the reef flat is currently below this calcification threshold 29.6% of the time in summer and 14.1% of the time in winter.

  15. The inhibition of neurons in the central nervous pathways for thermoregulatory cold defense induces a suspended animation state in the rat.

    Science.gov (United States)

    Cerri, Matteo; Mastrotto, Marco; Tupone, Domenico; Martelli, Davide; Luppi, Marco; Perez, Emanuele; Zamboni, Giovanni; Amici, Roberto

    2013-02-13

    The possibility of inducing a suspended animation state similar to natural torpor would be greatly beneficial in medical science, since it would avoid the adverse consequence of the powerful autonomic activation evoked by external cooling. Previous attempts to systemically inhibit metabolism were successful in mice, but practically ineffective in nonhibernators. Here we show that the selective pharmacological inhibition of key neurons in the central pathways for thermoregulatory cold defense is sufficient to induce a suspended animation state, resembling natural torpor, in a nonhibernator. In rats kept at an ambient temperature of 15°C and under continuous darkness, the prolonged inhibition (6 h) of the rostral ventromedial medulla, a key area of the central nervous pathways for thermoregulatory cold defense, by means of repeated microinjections (100 nl) of the GABA(A) agonist muscimol (1 mm), induced the following: (1) a massive cutaneous vasodilation; (2) drastic drops in deep brain temperature (reaching a nadir of 22.44 ± 0.74°C), heart rate (from 440 ± 13 to 207 ± 12 bpm), and electroencephalography (EEG) power; (3) a modest decrease in mean arterial pressure; and (4) a progressive shift of the EEG power spectrum toward slow frequencies. After the hypothermic bout, all animals showed a massive increase in NREM sleep Delta power, similarly to that occurring in natural torpor. No behavioral abnormalities were observed in the days following the treatment. Our results strengthen the potential role of the CNS in the induction of hibernation/torpor, since CNS-driven changes in organ physiology have been shown to be sufficient to induce and maintain a suspended animation state.

  16. Diurnal variations in pathways of photosynthetic carbon fixation in a freshwater cyanobacterium

    Science.gov (United States)

    Labiosa, R. G.; Arrigo, K. R.; Grossman, A.; Reddy, T. E.; Shrager, J.

    2003-04-01

    Understanding phytoplankton photosynthesis is critical to several fields including ecology and global biogeochemistry. The efficiency with which phytoplankton fix carbon depends upon the ambient light field, which is in turn dependent upon sun angle and the depth of mixing in the water column. In this pilot project, Synechocystis PCC 6803 was chosen as a model organism with which to study the molecular and physiological responses of phytoplankton to diurnal changes in light levels. Advantages of using this organism include that its genome has been sequenced, allowing the use of microarray technology, that it is readily grown as single colonies on plates and in liquid cultures, and that it is easy to manipulate genetically (generate and complement mutants). Axenic cultures of Synechocystis were grown under precisely controlled conditions in a "cyclodyne", a chemostat in which the light intensity cycles to mimic diurnal changes in light level, where the light consisted of sinusoidal daylight (400 μ mol photons m-2 s-1 at noon) followed by 12 hours of darkness for several weeks. After one week to allow the cells to acclimate to the light conditions, the cultures were sampled and extracted for RNA analysis every two hours over the course of several days. At these time points, absorption spectra, light scattering and chlorophyll a concentrations were determined. Initial results from Northern Blot hybridizations (examining RNA levels for individual genes) indicate that, the transcripts encoding photosynthetic proteins (i.e., PsbA2, PsaA and CpcB, in photosystem II, photosystem I, and phycobilisomes, respectively) are highest during the light. Initial results show that in the middle of the night, the psbA2 transcripts are 2-fold less while the psaA and cpcB are greater than 4-fold less than in the middle of the day. For the most part, the transcripts encoding photosynthetic proteins track the light cycle, although with different trends at daybreak and after night falls

  17. soil carbon pools within oak forest is endangered by global climate change in central mexico

    Science.gov (United States)

    García-Oliva, Felipe; Merino, Agustín; González-Rodriguez, Antonio; Chávez-Vergara, Bruno; Tapia-Torres, Yunuen; Oyama, Ken

    2016-04-01

    Forest soil represents the main C pool in terrestrial ecosystems. In particular, temperate forest ecosystems play an important role in the C budget among tropical countries, such as Mexico. For example, the temperate forest ecosystem contains higher C contents on average (295 Mg C ha-1) than the soil C associated with other ecosystems in Mexico (between 56 to 287 Mg C ha-1). At a regional scale, oak forest has the highest C content (460 Mg C ha-1) among the forest ecosystem in Michoacán State at Central Mexico. At the local scale, the soil C content is strongly affected by the composition of organic matter produced by the plant species. The oak species are very diverse in Mexico, distributed within two sections: Quercus sensu stricto and Lobatae. The oak species from Quercus s.s. section produced litterfall with lower concentrations of recalcitrant and thermostable compounds than oak species from Lobatae section, therefore the soil under the former species had higher microbial activity and nutrient availability than the soil under the later species. However, the forest fragment with higher amount of oak species from Quercus s.s. section increases the amount of soil C contents. Unfortunately, Quercus species distribution models for the central western region of Mexico predict a decrease of distribution area of the majority of oak species by the year 2080, as a consequence of higher temperatures and lower precipitation expected under climate change scenarios. Additionally to these scenarios, the remnant oak forest fragments suffer strong degradation due to uncontrolled wood extraction and deforestation. For this reason, the conservation of oak forest fragments is a priority to mitigate the greenhouse gases emission to the atmosphere. In order to enhance the protection of these forest fragments it is required that the society identify the ecosystem services that are provided by these forest fragments.

  18. Vertical flux of particulate organic carbon in the central South China Sea estimated from 234Th-238U disequilibria

    Institute of Scientific and Technical Information of China (English)

    MA Hao; ZENG Zhi; HE Jianhua; CHEN Liqi; YIN Mingduan; ZENG Shi; ZENG Wenyi

    2008-01-01

    234Th-238u disequilibria were applied to examine the particle dynamics in the euphotic zone of the central South China Sea during the spring 2002 cruise. The particulate organic carbon (POC), 234Th (including both dissolved and particulate) and 238U in the water column at three stations were determined. The profiles of 234Th/238U activity ratio at the three stations all showed consistent 234Th deficit as compared to 238U in the upper 100 m water column. Based on the profiles of the dissolved and particulate 234Th and a steady state box model, the dissolved 234Th scavenging rates, the particulate 234Th removal rates and their resident times were quantified. It was found that the POC downward export fluxes out of the upper 100 m euphotic zone ranged from 9.40 to 14.78 mmol.m-2.d-1. The results from this study provide new information for our understanding of carbon biogeochemical cycle in the South China Sea.

  19. Persistence of Carbonate Platform Environments in Central Mexico during the Oceanic Anoxic Event 2: impact of the Carribean Plateau?

    Science.gov (United States)

    Bomou, Brahimsamba; Adatte, Thierry; Föllmi, Karl; Arnaud-Vanneau, Annie; Fleitmann, Dominik

    2010-05-01

    The Cenomanian-Turonian Oceanic Anoxic Event 2 is described as an interruption of normal pelagic sediment deposition by several distinct intervals of widespread oceanic anoxia (Schlanger & Jenkyns, 1976; Jenkyns, 1980; Arthur et al., 1990) characterized by black shales deposition coinciding with a positive shift in carbon isotope excursion. Some authors show a relationship between OAEs and massive volcanic events associated with the emplacement of large igneous provinces (LIPs) and sea floor spreading at mid-ocean ridges (Kuroda et al., 2007; Snow et al., 2005). High metal abundance anomalies recorded in pelagic sections (e.g. Pueblo, Colorado) coincide with the massive volcanism that built the Carribean plateau (around 93-94 Ma), associated with the onset of OAE 2 (Snow et al., 2005). Mort et al., (2007) demonstrate that the onset of the OAE 2 was triggered by a short-lived but significant increase in phosphorus burial. The bottom waters became anoxic and switched from being a P sink to a P source, sustaining the productivity in a positive feedback loop. However, the behaviour of phosphorus and trace metals at larger scale, in different paleogeography and paleodepht is still poorly known. The Axaxacualco and Baranca el Cañon sections, located at the Guerrero-Morelos carbonate platform in southern Mexico exhibit a fully correlateable d13C curves. In the distal part of the carbonate platform at Axaxacualco, the maximum d13C positive excursion coincides with oligotrophic carbonate platform environments supported by low concentrations in P and characterized by abundant and diversified benthic microfauna and rudists. The impact of OAE appears may be more significant in the proximal part of the carbonate platform at Barranca, characterized by the deposition of thick laminated microbialites indicative of mesotrophic conditions. The Morelos Carbonate platform with oligotrophic to mesotrophic conditions was persistent throughout the entire OAE2 in Central Mexico despite

  20. Hydrologic characteristics of soils in the High Plains, northern Great Plains, and Central Texas Carbonates Regional Aquifer Systems

    Science.gov (United States)

    Dugan, Jack T.; Hobbs, Ryne D.; Ihm, Laurie A.

    1990-01-01

    Certain physical characteristics of soils, including permeability, available water capacity, thickness, and topographic position, have a measurable effect on the hydrology of an area. These characteristics control the rate at which precipitation infiltrates or is transmitted through the soil, and thus they have an important role in determining the rates of actual evapotranspiration (consumptive water use), groundwater recharge, and surface runoff. In studies of groundwater hydrology, it is useful to differentiate soils spatially according to their physical characteristics and to assign values that indicate their hydrologic responses.The principal purpose of this report is to describe the relation between the hydrologic characteristics of the soils in the study area and those environmental factors that affect the development and distribution of the soils. This objective will be achieved by (1) defining both qualitatively and quantitatively those soil characteristics that affect hydrology, and (2) classifying and delineating the boundaries of the soils in the study area according to these hydrologic characteristics.The study area includes the High Plains, Northern Great Plains, the Central Texas Carbonates, and parts of the Central Midwest Regional Aquifer Systems as described by the U.S. Geological Survey Regional Aquifer-System Analysis (RASA) Program (Sun, 1986, p.5and Sun, personal commun., June 1985) and shown in figures 1 through 5. The spatial patterns of the soils classified according to their quantifiable hydrologic characteristics will subsequently serve as an integral component in the analysis of actual evapotranspiration (consumptive water use), consumptive irrigation requirements, and potential ground-water recharge of the study area.The classification system used to describe the soils in this report is compatible with that of Dugan (1986). Dugan described the same characteristics of soils that are immediately underlain by principal aquifers of

  1. Sedimentology of a Mid-Late Ordovician carbonate mud-mound complex from the Kathmandu nappe in Central Nepal

    Science.gov (United States)

    Pas, Damien; Da Silva, Anne-Christine; Dhital, Megh Raj; Boulvain, Frédéric

    2011-08-01

    This sedimentological study of the Godavari quarry is the first relating to the Palaeozoic Tethyan sedimentary rocks of the Katmandu nappe (Central Nepal). Sedimentological analyses led to the identification of six microfacies belonging to a large carbonate mud-mound complex, which can be divided into mound, flank and off-mound main depositional settings. Identification of two dasycladaceans ( Dasyporell a cf. silurica ( Stolley, 1893) and Vermiporella sp.) in the mound facies gives a Mid-Late Ordovician age to this newly discovered Godavari carbonate mud-mound, which makes this mound one of the oldest ever described in the Asian continent. The mound microfacies are characterized by a high micritic content, the presence of stromatactis and the prevalence of red coloured sediments (the red pigmentation probably being related to organic precipitation of iron). The flank microfacies are characterized by a higher crinoid and argillaceous content and the presence of bio- and lithoclasts concentrated in argillaceous lenses. Finally, the off-mound microfacies show very few bioclasts and a high argillaceous content. Palaeoenvionmental interpretation of microfacies, in terms of bathymetry, leads us to infer that the Godavari mud-mound started to grow in a deep environment setting below the photic and wave action zones and that it evolved to occupy a location below the fair weather wave base. Cementation of cavities within the mound facies underlines a typical transition from a marine to a burial diagenetic environment characterized by: (1) a radiaxial non luminescent feroan calcite cement (marine) showing a bright orange luminescent band in its middle part; (2) a bright zoned orange fringe of automorphic feroan calcite (meteoric phreatic); (3) a dull orange xenomorphic feroan calcite cement in the centre of cavities (burial) and (4) a saddle dolomite within the centre of larger cavities. The faunal assemblage (diversity and relative proportion) of the Godavari mound facies

  2. Characterization of the oxygen tolerance of a hydrogenase linked to a carbon monoxide oxidation pathway in Rubrivivax gelatinosus.

    Science.gov (United States)

    Maness, Pin-Ching; Smolinski, Sharon; Dillon, Anne C; Heben, Michael J; Weaver, Paul F

    2002-06-01

    A hydrogenase linked to the carbon monoxide oxidation pathway in Rubrivivax gelatinosus displays tolerance to O2. When either whole-cell or membrane-free partially purified hydrogenase was stirred in full air (21% O2, 79% N2), its H2 evolution activity exhibited a half-life of 20 or 6 h, respectively, as determined by an anaerobic assay using reduced methyl viologen. When the partially purified hydrogenase was stirred in an atmosphere containing either 3.3 or 13% O2 for 15 min and evaluated by a hydrogen-deuterium (H-D) exchange assay, nearly 80 or 60% of its isotopic exchange rate was retained, respectively. When this enzyme suspension was subsequently returned to an anaerobic atmosphere, more than 90% of the H-D exchange activity was recovered, reflecting the reversibility of this hydrogenase toward O2 inactivation. Like most hydrogenases, the CO-linked hydrogenase was extremely sensitive to CO, with 50% inhibition occurring at 3.9 microM dissolved CO. Hydrogen production from the CO-linked hydrogenase was detected when ferredoxins of a prokaryotic source were the immediate electron mediator, provided they were photoreduced by spinach thylakoid membranes containing active water-splitting activity. Based on its appreciable tolerance to O2, potential applications of this hydrogenase are discussed.

  3. Fluxes of nitrous oxide and carbon dioxide over four potential biofuel crops in Central Illinois

    Science.gov (United States)

    Zeri, M.; Hickman, G. C.; Bernacchi, C.

    2009-12-01

    Nitrous oxide (N2O) and carbon dioxide (CO2) are important greenhouse gases that contribute to global climate change. Agriculture is a significant source of N2O to the atmosphere due to the use of nitrogen-based fertilizers. Fluxes of N2O and CO2 are measured using the flux-gradient technique over four different crops at the Energy Farm, a University of Illinois research facility in Urbana, Illinois. Measurements started in June of 2009 and are part of a project that aims to assess the impacts of potential biofuel crops on the carbon, water and nitrogen cycles. The species chosen are Maize (Zea mays), Miscanthus (Miscanthus x giganteus), Switchgrass (Panicum virgatum) and Prairie (a mix of several native species). The choice of species was based on their potential for the production of second-generation biofuels, i.e., fuels derived from the decomposition of the cellulosic material in the plant biomass. The use of corn residue for cellulosic biofuels might impact the carbon cycle through the reduction of soil organic content. Miscanthus is a perennial grass with great potential for biomass production. However, the total water used during the growing season and its water use efficiency might impose limits on the regions where this biofuel crop can be sustainably planted on a large scale. Switchgrass and the prairie species are less productive but might be suited for being well adapted and easy to establish. This study is the first side-by-side comparison of fluxes of N2O for these agro-ecosystems. The measurements are performed at micrometeorological towers placed at the center of 4 ha plots. The air is sampled at two heights over the vegetation and is analyzed in a tunable diode laser (TDL) installed nearby. A valve system cycles the TDL measurements trough all the intakes in the plots. The fluxes are calculated using the flux-gradient method, which requires the knowledge of the scalar vertical gradient as well as of the friction velocity (u*) and the Monin

  4. Reservoir Potential of Silurian Carbonate Mud Mounds in the Southern Sichuan Basin, Central China

    Institute of Scientific and Technical Information of China (English)

    ZHAO Wenzhi; YANG Xiaoping; Steve KERSHAW; ZHANG Baomin

    2006-01-01

    Lower Silurian mud mounds of the Shinuilan Formation, located in the southern Sichuan Basin, China, have developed in open shelf settings in deeper water than shallow-water reef-bearing limestones that occur in the region. An integration of the outcrop, drill data and seismic profiles show that contemporaneous faults have controlled the boundary and distribution of the sedimentary facies of Lower Silurian rocks in the southern Sichuan Basin. Mounds appear to have developed in the topographic lows formed by synsedimentary faulting, on the shelf of the Yangtze Platform. Average mound thickness is 20 m, maximum 35 m. Mounds are composed mainly of micrite, possibly microbially bound, and are overlain by shales. Mound tops are preferentially dolomitized, with the Mg2+ source probably from the clay content of the mound-top carbonate. Microfacies analysis and reconstruction of the diagenetic history reveal that the mound tops have higher porosity, and are gas targets; in contrast, mound cores and limbs show pores filled by three generations of calcite cement, and therefore have a low gas potential.

  5. DISTRIBUTION OF ORGANIC CARBON IN DIFFERENT SOIL FRACTIONS IN ECOSYSTEMS OF CENTRAL AMAZONIA

    Directory of Open Access Journals (Sweden)

    Jean Dalmo de Oliveira Marques

    2015-02-01

    Full Text Available Organic matter plays an important role in many soil properties, and for that reason it is necessary to identify management systems which maintain or increase its concentrations. The aim of the present study was to determine the quality and quantity of organic C in different compartments of the soil fraction in different Amazonian ecosystems. The soil organic matter (FSOM was fractionated and soil C stocks were estimated in primary forest (PF, pasture (P, secondary succession (SS and an agroforestry system (AFS. Samples were collected at the depths 0-5, 5-10, 10-20, 20-40, 40-60, 60-80, 80-100, 100-160, and 160-200 cm. Densimetric and particle size analysis methods were used for FSOM, obtaining the following fractions: FLF (free light fraction, IALF (intra-aggregate light fraction, F-sand (sand fraction, F-clay (clay fraction and F-silt (silt fraction. The 0-5 cm layer contains 60 % of soil C, which is associated with the FLF. The F-clay was responsible for 70 % of C retained in the 0-200 cm depth. There was a 12.7 g kg-1 C gain in the FLF from PF to SS, and a 4.4 g kg-1 C gain from PF to AFS, showing that SS and AFS areas recover soil organic C, constituting feasible C-recovery alternatives for degraded and intensively farmed soils in Amazonia. The greatest total stocks of carbon in soil fractions were, in decreasing order: (101.3 Mg ha-1 of C - AFS > (98.4 Mg ha-1 of C - FP > (92.9 Mg ha-1 of C - SS > (64.0 Mg ha-1 of C - P. The forms of land use in the Amazon influence C distribution in soil fractions, resulting in short- or long-term changes.

  6. Export of dissolved organic carbon from the Penobscot River basin in north-central Maine

    Science.gov (United States)

    Huntington, Thomas G.; Aiken, George R.

    2013-01-01

    Dissolved organic carbon (DOC) flux from the Penobscot River and its major tributaries in Maine was determined using continuous discharge measurements, discrete water sampling, and the LOADEST regression software. The average daily flux during 2004–2007 was 71 kg C ha−1 yr−1 (392 Mt C d−1), an amount larger than measured in most northern temperate and boreal rivers. Distinct seasonal variation was observed in the relation between concentration and discharge (C–Q). During June through December (summer/fall), there was a relatively steep positive C–Q relation where concentration increased by a factor of 2–3 over the approximately 20-fold range of observed stream discharge for the Penobscot River near Eddington, Maine. In contrast, during January through May (winter/spring), DOC concentration did not increase with increasing discharge. In addition, we observed a major shift in the C–Q between 2004–2005 and 2006–2007, apparently resulting from unprecedented rainfall, runoff, and soil flushing beginning in late fall 2005. The relative contribution to the total Penobscot River basin DOC flux from each tributary varied dramatically by season, reflecting the role of large regulated reservoirs in certain basins. DOC concentration and flux per unit watershed area were highest in tributaries containing the largest areas in palustrine wetlands. Tributary DOC concentration and flux was positively correlated to percentage wetland area. Climatic or environmental changes that influence the magnitude or timing of river discharge or the abundance of wetlands will likely affect the export of DOC to the near-coastal ocean.

  7. Impact of predicted changes in rainfall and atmospheric carbon dioxide on maize and wheat yeilds in the Central Rift Valley of Ethiopia

    NARCIS (Netherlands)

    Muluneh, A.; Biazin, B.; Stroosnijder, L.; Bewket, W.; Keesstra, S.D.

    2015-01-01

    This study assesses potential impacts of climate change on maize and wheat yields in the Central Rift Valley (CRV) of Ethiopia. We considered effects of elevated atmospheric carbon dioxide (CO2) and changes in rainfall during the main (Kiremt) and the short (Belg) rainfall cropping seasons during th

  8. Flocculation of Allochthonous Dissolved Organic Matter – a Significant Pathway of Sedimentation and Carbon Burial in Lakes

    OpenAIRE

    von Wachenfeldt, Eddie

    2008-01-01

    Inland waters receive substantial amounts of organic carbon from adjacent watersheds. Only about half of the carbon exported from inland waters reaches the oceans, while the remainder is lost en route. This thesis identifies flocculation as an important and significant fate of carbon in the boreal landscape. Flocculation reallocates organic carbon from the dissolved state into particles which are prone to settle. Thus, flocculation relocates organic carbon from the water column to the sedimen...

  9. {sup 210}Pb dating of sediments from the central and northern Adriatic Sea: deposition and preservation of sedimentary organic carbon

    Energy Technology Data Exchange (ETDEWEB)

    Hamilton, T. F., LLNL

    1998-04-01

    Lead-210 ({sup 21O}Pb) and organic C depth distribution profiles in sediments from the northern and central Adriatic Sea were measured as part of the EEC funded project on Eutrophic Limits of the Northern Adriatic (ELNA). {sup 210}Pb derived mass-accumulation rates decrease southward from between 0.15 and 0.2 g cm{sup -2}y{sup -1} close to the Po River outflow (> 24 m, water depth) to less than 0.04 g cm{sup -2}y{sup -1} in the Jabuka Pit (246 m, water depth) in the central Adriatic Sea. The mass- accumulation rates obtained in the Jabuka Pit correspond to mean sedimentation rates of about 0.03 cm y{sup -1} (ref. porosity = 0.5) and fall between 5 to 20 times lower than rates found for north Adriatic shelf cores. Estimated sedimentation rates are considered as upper limits because of the possible effects of bioturbation and physical disturbance on the {sup 21O}Pb sedimentary record but are consistent with data from previous work. Rates of sediment accumulation and carbon burial appear to be strongly influenced by the transport of fluvial materials from land and transport of fine-grained particles. First-order estimates of organic C burial rates into surface sediment ranged from 1 to 0.028 mMol cm{sup -2}y{sup -1} between the Po delta and the Jabuka Pit regions, respectively. We estimate that a maximum of 50% of organic C preserved in surface sediment may be derived from biological production in the overlying water column.

  10. Decomposition, nitrogen and carbon mineralization from food and cover crop residues in the central plateau of Haiti.

    Science.gov (United States)

    Lynch, M J; Mulvaney, M J; Hodges, S C; Thompson, T L; Thomason, W E

    2016-01-01

    Cover crops are a major focus of conservation agriculture efforts because they can provide soil cover and increase nutrient availability after their mineralization in cropping systems. To evaluate the effect of residue type and placement on rate of decomposition and carbon (C) and nitrogen (N) mineralization, residues from two food crops, maize (Zea mays L.) and common bean (Phaseolus vulgaris L.), and two promising cover crops, sunn hemp (Crotalaria juncea L.) and sorghum sudangrass (Sorghum bicolor [L.] Moench x S. bicolor var. Sudanese [Piper] Stapf) were used in a litterbag study in the Central Plateau region of Haiti from May to September, 2013. Residues were placed in litterbags at a rate equivalent to 3.25 Mg residue ha(-1) either on the soil surface or buried at 15 cm to represent a tilled and no-tillage system, respectively. Initial C:N ratios were: maize > common bean > sorghum sudangrass > sunn hemp. Highest residue mass loss rates and C and N mineralization generally occurred in the reverse order. Overall, surface-placed residues decomposed more slowly with 40 and 17 % of initial residue mass of surface and buried residues, respectively, remaining at 112 days. Carbon and N mineralization was higher when residues were buried. Net N mineralization of buried residues was 0.12, 0.07, 0.06, and 0.03 g N g residue(-1) for sunn hemp, sorghum sudangrass, maize, and common bean, respectively over 112 days. To achieve the goal of increasing nutrient supply while maintaining year-round cover, a combination of grass and legume cover crops may be required with benefits increasing over multiple seasons. PMID:27429883

  11. Analysis of sensitive CO2 pathways and genes related to carbon uptake and accumulation in Chlamydomonas reinhardtii through genomic scale modeling and experimental validation

    Directory of Open Access Journals (Sweden)

    Flavia Vischi Winck

    2016-02-01

    Full Text Available The development of microalgae sustainable applications needs better understanding of microalgae biology. Moreover, how cells coordinate their metabolism towards biomass accumulation is not fully understood. In this present study, flux balance analysis (FBA was performed to identify sensitive metabolic pathways of Chlamydomonas reinhardtii under varied CO2 inputs. The metabolic network model of Chlamydomonas was updated based on the genome annotation data and sensitivity analysis revealed CO2 sensitive reactions. Biological experiments were performed with cells cultivated at 0.04% (air, 2.5%, 5%, 8% and 10% CO2 concentration under controlled conditions and cell growth profiles and biomass content were measured. Pigments, lipids, proteins and starch were further quantified for the reference low (0.04% and high (10% CO2 conditions. The expression level of candidate genes of sensitive reactions was measured and validated by quantitative real time qPCR. The sensitive analysis revealed mitochondrial compartment as the major affected by high CO2 levels and glycolysis/gluconeogenesis, glyoxylate and dicarboxylate metabolism among the affected metabolic pathways. Genes coding for glycerate kinase (GLYK, glycine cleavage system, H-protein (GCSH, NAD-dependent malate dehydrogenase (MDH3, low-CO2 inducible protein A (LCIA, carbonic anhydrase 5 (CAH5, E1 component, alpha subunit (PDC3, dual function alcohol dehydrogenase/acetaldehyde dehydrogenase (ADH1 and phosphoglucomutase (GPM2, were defined, among other genes, as sensitive nodes in the metabolic network simulations. These genes were experimentally responsive to the changes in the carbon fluxes in the system. We performed metabolomics analysis using mass spectrometry validating the modulation of carbon dioxide responsive pathways and metabolites. The changes on CO2 levels mostly affected the metabolism of amino acids found in the photorespiration pathway. Our updated metabolic network was compared to

  12. Robust Control of PEP Formation Rate in the Carbon Fixation Pathway of C4 Plants by a Bi-functional Enzyme

    Directory of Open Access Journals (Sweden)

    Hart Yuval

    2011-10-01

    Full Text Available Abstract Background C4 plants such as corn and sugarcane assimilate atmospheric CO2 into biomass by means of the C4 carbon fixation pathway. We asked how PEP formation rate, a key step in the carbon fixation pathway, might work at a precise rate, regulated by light, despite fluctuations in substrate and enzyme levels constituting and regulating this process. Results We present a putative mechanism for robustness in C4 carbon fixation, involving a key enzyme in the pathway, pyruvate orthophosphate dikinase (PPDK, which is regulated by a bifunctional enzyme, Regulatory Protein (RP. The robust mechanism is based on avidity of the bifunctional enzyme RP to its multimeric substrate PPDK, and on a product-inhibition feedback loop that couples the system output to the activity of the bifunctional regulator. The model provides an explanation for several unusual biochemical characteristics of the system and predicts that the system's output, phosphoenolpyruvate (PEP formation rate, is insensitive to fluctuations in enzyme levels (PPDK and RP, substrate levels (ATP and pyruvate and the catalytic rate of PPDK, while remaining sensitive to the system's input (light levels. Conclusions The presented PPDK mechanism is a new way to achieve robustness using product inhibition as a feedback loop on a bifunctional regulatory enzyme. This mechanism exhibits robustness to protein and metabolite levels as well as to catalytic rate changes. At the same time, the output of the system remains tuned to input levels.

  13. Ozone, carbon monoxide and nitrogen oxides time series at four alpine GAW mountain stations in central Europe

    Directory of Open Access Journals (Sweden)

    S. Gilge

    2010-12-01

    Full Text Available Long-term, ground based in-situ observations of ozone (O3 and its precursor gases nitrogen dioxide (NO2 and carbon monoxide (CO from the four sites Hohenpeissenberg and Zugspitze (D, Sonnblick (A and Jungfraujoch (CH are presented for the period 1995–2007. These Central European alpine mountain observatories cover an altitude range of roughly 1000 to 3500 m. Comparable analytical methods and common quality assurance (QA procedures are used at all sites. For O3 and CO, calibration is linked to primary calibrations (O3 or CO standards provided by the Central Calibration Laboratory (CCL at NOAA/ESRL. All stations have been audited by the World Calibration Centre (WCC for CO and O3 (WCC-Empa; CH. Data from long-term measurements of NO2 and CO are only available from Hohenpeissenberg and Jungfraujoch. Both sites show slightly decreasing mixing ratios of the primarily emitted NO2 and the partly anthropogenically emitted CO between 1995 and 2007. The findings are generally consistent with shorter observation periods at Zugspitze and Sonnblick and thus are considered to represent regional changes in Central European atmospheric composition at this altitude range. Over the same period, 1995–2007, the O3 mixing ratios have slightly increased at three of the four sites independent of wind sector. Trends are often more pronounced in winter and less in summer; highest declines of NO2 and CO are observed in winter and the lowest in summer, whereas the strongest O3 increase was detected in winter and lowest or even decline in summer, respectively. Weekly cycles demonstrate anthropogenic impact at all elevations with enhanced NO2 on working days compared to weekends. Enhanced O3 values on working days indicating photochemical production from anthropogenic precursors are only observed in summer, whereas in all other seasons anti

  14. Ozone, Carbon monoxide and Nitrogen oxides time series at four Alpine GAW mountain stations in Central Europe

    Directory of Open Access Journals (Sweden)

    S. Gilge

    2010-08-01

    Full Text Available Long-term, ground based in-situ observations of Ozone (O3 and its precursor gases Nitrogen dioxide (NO2 and Carbon monoxide (CO from the four sites Hohenpeissenberg and Zugspitze (D, Sonnblick (A and Jungfraujoch (CH are presented for the period 1995–2007. These Central European alpine mountain observatories cover an altitude range of roughly 1000 to 3500 m. Comparable analytical methods and common quality assurance (QA procedures are used at all sites. For O3 and CO, calibration is linked to primary calibrations (O3 or CO standards provided by the Central Calibration Laboratory (CCL at NOAA/ESRL. All stations have been audited by the World Calibration Centre (WCC for CO and O3 (WCC-Empa; CH. Data from long-term measurements of NO2 and CO are only available from Hohenpeissenberg and Jungfraujoch. Both sites show slightly decreasing mixing ratios of the primarily emitted NO2 and the partly anthropogenically emitted CO between 1995 and 2007. The findings are generally consistent with shorter observation periods at Zugspitze and Sonnblick and thus are considered to represent regional changes in Central European atmospheric composition at this altitude range. Over the same period 1995–2007, the O3 mixing ratios have slightly increased at three of the four sites. This was observed independent of wind sector and for most seasons, with a tendency to higher positive trends in winter and lower and partly negative trends in summer. Trends are often more pronounced in winter and less in summer; highest declines of NO2 and CO are observed in winter and the lowest in summer, whereas the highest rate of O3 increase was detected in winter and lowest in summer, respectively. Weekly cycles demonstrate anthropogenic impact at all elevations with enhanced NO2 on working days compared to weekends. Enhanced O3 values on working days

  15. A Dialogue between the Sirène Pathway in Synergids and the Fertilization Independent Seed Pathway in the Central Cell Controls Male Gamete Release during Double Fertilization in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Nicolas Rotman; Mathieu Gourgues; Anne-Elisabeth Guitton; Jean-Emmanuel Faure; Frédéric Berger

    2008-01-01

    Angiosperms sexual reproduction involves interactions between the two female gametes in the embryo sac and the two male gametes released by the pollen tube.The two synergids of the embryo sac express the FERONIA/SIRENE receptor-like kinase,which controls the discharge of the two sperm cells from the pollen tube.FER/SRN may respond to a ligand from the pollen tube.Alternatively,the interaction between FER/SRN and a ligand from the embryo sac may lead to a state of competence of the synergids allowing pollen tube discharge.Here,we report the new mutant scylla(syl)impaired in the controI of pollen tube discharge.This mutant also produces autonomous endosperm development in absence of tertilization-a trait associated with the FERTILIZATION INDEPENDENT SEED (FIS) mutant class.This led us to identify autonomous endosperm in srn mutants and to demonstrate synergistic interactions between srn and the fis mutants.In addition,the fis mutants display defects in pollen tube discharge as in srn and syl mutants,confirming the interaction between the two pathways.Our findings suggest that pollen tube discharge is controlled by an interaction between the synergids expressing SRN/FER and the central cell expressing FIS genes.

  16. Charge exchange recombination spectroscopy measurements in the extreme ultraviolet region of central carbon concentrations during high power neutral beam heating in TFTR [Tokamak Fusion Test Reactor

    International Nuclear Information System (INIS)

    The carbon concentration in the central region of TFTR discharges with high power neutral beam heating has been measured by charge-extracted recombination spectroscopy (CXRS) of the C+5 n = 3--4 transition in the extreme ultraviolet region. The carbon concentrations were deduced from absolute measurements of the line brightness using a calculation of the beam attenuation and the appropriate cascade-corrected line excitation rates. As a result of the high ion temperatures in most of the discharges, the contribution of beam halo neutrals to the line brightness was significant and therefore had to be included in the modeling of the data. Carbon concentrations have been measured in discharges with Ip = 1.0-1.6 MA and beam power in the range of 2.6-30 MW, including a number of supershots. The results are in good agreement with carbon concentrations deduced from the visible bremsstrahlung Zeff and metallic impurity concentrations measured by x-ray pulse-height analysis, demonstrating the reliability of the atomic rates used in the beam attenuation and line excitation calculations. Carbon is the dominant impurity species in these discharges; the oxygen concentration measured via CXRS in a high beam power case was 0.0006 of ne, compard to 0.04 for carbon. Trends with Ip and beam power in the carbon concentration and the inferred deuteron concentration are presented. The carbon concentration is independent of Ip and decreases from 0.13 at 2.6 MW beam power to 0.04 at 30 MW, while the deuteron concentration increases from 0.25 to 0.75 over the same range of beam power. These changes are primarily the result of beam particle fueling, as the carbon density did not vary significantly with beam power. The time evolutions of the carbon and deuteron concentrations during two high power beam pulses, one which exhibited a carbon bloom and one which did not, are compared. 30 refs., 12 figs., 2 tabs

  17. Miocene climate as recorded on slope carbonates : examples from Malta (Central Mediterranean) and Northeastern Australia (Marion Plateau, ODP LEG 194)

    Science.gov (United States)

    John, Cédric Michaël

    2003-08-01

    This study investigated the slope carbonates of two Miocene carbonate systems: the Maltese Islands (in the Central Mediterranean) and the Marion Plateau (Northeastern Australia, drilled during ODP Leg 194). The aim of the study was to trace the impact of the Miocene cooling steps (events Mi1-Mi6) in these carbonate systems, especially the Mi3 event, which took place around 13.6 Ma and deeply impacted the marine oxygen isotope record. This event also profoundly impacted oceanographic and climatic patterns, eventually leading to the establishment of the modern ice-house world. In particular, East Antarctica became ice covered at that period. The rational behind the present study was to investigate the impact that this event had on shallow water systems in order to complement the deep-sea record and hence acquire a more global perspective on Miocene climate change. The Maltese Islands were investigated for trends in bulk-rock carbon and oxygen isotopes, as well as bulk-rock mineralogy, clay minerals analysis and organic geochemisty. Results showed that the mid Miocene cooling event deeply impacted sedimentation at that location by changing sedimentation from carbonate to clay-rich sediments. Moreover, it was discovered that each phase of Antarctic glaciation, not just the major mid Miocene event, resulted in higher terrigenous input on Malta. Mass accumulation rates revealed that this was linked to increased runoff during periods when Antarctica was glaciated, and thus that the carbonate sediments were “diluted” by clay-rich sediments. The model subsequently developed to explain this implies feedback from Antarctic glaciations creating cold, dense air masses that push the ITCZ Northward, thus increasing precipitation on the North African subcontinent. Increased precipitation (or stronger African monsoon) accelerated continental weathering and runoff, thus bringing more terrigenous sediment to the paleo-location of the slope sediments of Malta. Spectral analysis of

  18. Effects of modulation of pentose-phosphate pathway on biosynthesis of ansamitocins in Actinosynnema pretiosum.

    Science.gov (United States)

    Fan, Yuxiang; Hu, Fengxian; Wei, Liujing; Bai, Linquan; Hua, Qiang

    2016-07-20

    Ansamitocins, produced by Actinosynnema pretiosum, are a group of maytansinoid antibiotics that block the assembly of tubulin into functional microtubules. The precursors of ansamitocin biosynthesis are generally derived from the Embden-Meyerhof-Parnas (EMP) pathway and the tricarboxylic acid cycle. In this study, central carbon flux distributions were analyzed by (13)C-based flux analysis to reveal the contribution of individual central carbon metabolism pathways. To direct more carbon flux into ansamitocin biosynthesis, pentose phosphate (PP) pathway only and the combination of PP pathway and Entner-Doudoroff (ED) pathway were weakened, respectively. Ansamitocin P-3 (AP-3) productions by both kinds of pathways weakened mutant strains were significantly enhanced in chemically defined medium. In order to draw metabolic flux to the biosynthesis of ansamitocins more efficiently, heterologous phosphoglucomutase was subsequently overexpressed based on a mutant strain with combinational regulation of PP pathway and ED pathway. More fluxes were successfully directed into the UDP-glucose synthetic pathway and the AP-3 production was further improved in this case, reaching approximately 185mg/L in fermentation medium. It was demonstrated that eliminating the bypass pathways and favoring the precursor synthetic pathway could effectively improve ansamitocin production by A. pretiosum, suggesting a promising role of metabolic strategy in improving secondary metabolite production. PMID:27173582

  19. Pathway focused protein profiling indicates differential function for IL-1B, -18 and VEGF during initiation and resolution of lung inflammation evoked by carbon nanoparticle exposure in mice

    Directory of Open Access Journals (Sweden)

    Hamelmann Eckard

    2009-12-01

    Full Text Available Abstract Background Carbonaceous nanoparticles possess an emerging source of human exposure due to the massive release of combustion products and the ongoing revolution in nanotechnology. Pulmonary inflammation caused by deposited nanoparticles is central for their adverse health effects. Epidemiological studies suggest that individuals with favourable lung physiology are at lower risk for particulate matter associated respiratory diseases probably due to efficient control of inflammation and repair process. Therefore we selected a mouse strain C3H/HeJ (C3 with robust lung physiology and exposed it to moderately toxic carbon nanoparticles (CNP to study the elicited pulmonary inflammation and its resolution. Methods 5 μg, 20 μg and 50 μg CNP were intratracheally (i.t. instilled in C3 mice to identify the optimal dose for subsequent time course studies. Pulmonary inflammation was assessed using histology, bronchoalveolar lavage (BAL analysis and by a panel of 62 protein markers. Results 1 day after instillation of CNP, C3 mice exhibited a typical dose response, with the lowest dose (5 μg representing the 'no effect level' as reflected by polymorphonuclear leucocyte (PMN, and BAL/lung concentrations of pro-inflammatory proteins. Histological analysis and BAL-protein concentration did not reveal any evidence of tissue injury in 20 μg CNP instilled animals. Accordingly time course assessment of the inflammatory response was performed after 3 and 7 days with this dose (20 μg. Compared to day 1, BAL PMN counts were significantly decreased at day 3 and completely returned to normal by day 7. We have identified protein markers related to the acute response and also to the time dependent response in lung and BAL. After complete resolution of PMN influx on day 7, we detected elevated concentrations of 20 markers that included IL1B, IL18, FGF2, EDN1, and VEGF in lung and/or BAL. Biological pathway analysis revealed these factors to be involved in a

  20. Carbon of Woody Debris in Plateau-type Karst Evergreen and Deciduous Broad-leaved Mixed Forest of Central Guizhou Province

    Science.gov (United States)

    Wu, Y.; Ni, J.; Liu, L.; Guo, C.

    2014-12-01

    Woody debris (WD) is an essential structural and functional component of forest ecosystems, and plays very significant roles for the biogeochemical cycling of carbon and nutrients. Coarse woody debris (CWD) is considered to be the major part in forest WD and it is primarily composed of logs, snags, stumps and large branches, while fine woody debris (FWD) mainly consists of small twigs. Composition, spatial distribution and carbon storage of WD have been studied in plateau-type karst evergreen and deciduous broad-leaved mixed forest in Tianlong Mountain of central Guizhou Province. Results showed that the carbon storage of WD in karst forests was less than non-karst forests. The major components of WD were fallen trees and snags with 10-20 cm in diameter. Fallen trees and snags with diameter greater than 20 cm were the smallest part of WD. The situation of WD in this region reflects the structural characteristics of WD in mid-late stage of plateau-type karst evergreen and deciduous broad-leaved mixed forest succession. The potential contribution of WD to the regional carbon cycle, and its relationship with climate change were finally discussed. The WD (especially CWD) plays an important role in the carbon cycle of karst forest. Forest WD production and decay rates may partially depend on climatic conditions, the accumulation of CWD and FWD carbon stocks in forests may be correlated with climate. Key words: woody debris, karst forests, carbon storage, spatial distribution, CWD, FWD.

  1. Synthesizing the Use of Carbon Isotope (14C and 13C) Approaches to Understand Rates and Pathways for Permafrost C Mobilization and Mineralization

    Science.gov (United States)

    Estop-Aragones, C.; Olefeldt, D.; Schuur, E.

    2015-12-01

    To better understand the permafrost carbon (C) feedback it is important to synthesize our current knowledge, and knowledge gaps, of how permafrost thaw can cause in situ mineralization or downstream mobilization of aged soil organic carbon (SOC) and the rate of this release. This potential loss of old SOC may occur via gaseous flux of CO2 and CH4 exchanged between soil and the atmosphere and via waterborne flux as DOC, POC (and their subsequent decomposition and release to the atmosphere). Carbon isotope (14C and 13C) approaches have been used to estimate both rates and pathways for permafrost C mobilization and mineralization. Radiocarbon (14C) has been used to estimate the contribution of aged C to overall respiration or waterborne C export. We aim to contrast results from radiocarbon studies, in order to assess differences between ecosystems (contrasting wet and dry ecosystems), thaw histories (active layer deepening or thermokarst landforms), greenhouse gas considered (CO2 and CH4) and seasons. We propose to also contrast methodologies used for assessing the contribution of aged C to overall C balance, and include studies using 13C data. Biological fractionation of 13C during both uptake and decomposition has been taken advantage of both in order to aid the interpretation of 14C data and on its own to assess sources and mineralization pathways. For example, 13C data has been used to differentiate between CH4 production pathways, and the relative contribution of anaerobic CO2 production to overall respiration. Overall, carbon isotope research is proving highly valuable for our understanding of permafrost C dynamics following thaw, and there is a current need to synthesize the available literature.

  2. Mass concentrations of black carbon measured by four instruments in the middle of Central East China in June 2006

    Science.gov (United States)

    Kanaya, Y.; Komazaki, Y.; Pochanart, P.; Liu, Y.; Akimoto, H.; Gao, J.; Wang, T.; Wang, Z.

    2008-12-01

    Mass concentrations of black carbon (BC) were determined in June 2006 at the top of Mount Tai (36.26° N, 117.11° E, 1534 m a.s.l.), located in the middle of Central East China, using four different instruments: a multi-angle absorption photometer (5012 MAAP, Thermo), a particle soot absorption photometer (PSAP, Radiance Research), an ECOC semi-continuous analyzer (Sunset Laboratory) and an Aethalometer (AE-21, Magee Scientific). High correlation coefficients (R2>0.88) were obtained between the measurements of the BC mass concentrations made using the different instruments. From the range of the slopes of the linear least-square fittings, we concluded that BC concentrations regionally-representative of the area were measured in a range with a maximum-to-minimum ratio of 1.5 (an exception was that the BC (PM2.5) concentrations derived from MAAP were ~2 times higher than the optical measurements (PM2.5) derived from the ECOC analyzer). While this range is significant, it is still sufficiently narrow to better constrain the large and highly uncertain emission rate of BC from Central East China. In detail, two optical instruments (the MAAP and the PSAP equipped with a heated inlet 400°C) tended to give higher concentrations than the thermal EC concentrations observed by the ECOC analyzer. The ratios of optical BC to thermal EC showed a positive correlation with the OC/EC ratio reported by the ECOC analyzer, suggesting two explanations. One is that the optical instruments overestimated BC concentrations in spite of careful cancellation of the scattering effect in the MAAP instrument and the expected evaporation of volatile species by heating the inlet of the PSAP instrument. The other is that the determined split points between OC and EC were too late when a large amount of OC underwent charring during the analysis, resulting in an underestimation of EC by the ECOC analyzer. High ratios of optical BC to thermal EC were recorded when the NOx/NOy ratio was low, implying

  3. Mass concentrations of black carbon measured by four instruments in the middle of Central East China in June 2006

    Directory of Open Access Journals (Sweden)

    Y. Kanaya

    2008-12-01

    Full Text Available Mass concentrations of black carbon (BC were determined in June 2006 at the top of Mount Tai (36.26° N, 117.11° E, 1534 m a.s.l., located in the middle of Central East China, using four different instruments: a multi-angle absorption photometer (5012 MAAP, Thermo, a particle soot absorption photometer (PSAP, Radiance Research, an ECOC semi-continuous analyzer (Sunset Laboratory and an Aethalometer (AE-21, Magee Scientific. High correlation coefficients (R2>0.88 were obtained between the measurements of the BC mass concentrations made using the different instruments. From the range of the slopes of the linear least-square fittings, we concluded that BC concentrations regionally-representative of the area were measured in a range with a maximum-to-minimum ratio of 1.5 (an exception was that the BC (PM2.5 concentrations derived from MAAP were ~2 times higher than the optical measurements (PM2.5 derived from the ECOC analyzer. While this range is significant, it is still sufficiently narrow to better constrain the large and highly uncertain emission rate of BC from Central East China. In detail, two optical instruments (the MAAP and the PSAP equipped with a heated inlet 400°C tended to give higher concentrations than the thermal EC concentrations observed by the ECOC analyzer. The ratios of optical BC to thermal EC showed a positive correlation with the OC/EC ratio reported by the ECOC analyzer, suggesting two explanations. One is that the optical instruments overestimated BC concentrations in spite of careful cancellation of the scattering effect in the MAAP instrument and the expected evaporation of volatile species by heating the inlet of the PSAP instrument. The other is that the determined split points between OC and EC were too late when a large amount of OC underwent charring during the analysis, resulting in an underestimation of EC by the ECOC analyzer. High ratios of optical BC to thermal EC were

  4. Central composite design approach towards optimization of flamboyant pods derived steam activated carbon for its use as heterogeneous catalyst in transesterification of Hevea brasiliensis oil

    International Nuclear Information System (INIS)

    Highlights: • Activated carbon was prepared from novel precursor flamboyant pods (Delonix regia). • Activation process was optimized using central composite design approach. • Prepared activated carbon at optimized condition was used as support for KOH. • Carbon based heterogeneous catalyst was used in transesterification of HBO. • Effect of catalyst loading and alcohol ratio on biodiesel yield was studied. - Abstract: The present investigation emphasises the preparation of carbon based KOH impregnated heterogeneous catalyst from flamboyant pods (Delonix regia) for the production of biodiesel from novel feedstock Hevea brasiliensis oil (HBO). Initially, carbonized char was physically activated by superheated steam and the process was optimized to study the effects of activation time and temperature by central composite design approach (CCD) using response surface methodology (RSM). Activated carbon was impregnated with KOH at four different ratios. Biodiesel production process was carried out at constant temperature 60 °C, reaction time 1 h, and 5 g of carbon based catalyst at varying quantities of catalyst loading (0.5, 2, 3.5, 5 wt%) and methanol to oil ratio (5:1–20:1). The influence of parameters on the biodiesel yield at varied condition was studied. Maximum yield of 89.3% was obtained at methanol to oil ratio 15:1 and catalyst loading 3.5 wt% and corresponding yield at same process parameters was observed to be 88.7% implying the significant activity of catalyst in reutilization. Produced biodiesel was characterized following ASTM standards. The experimental analysis confirmed that the carbonaceous catalyst developed from flamboyant pods under optimized condition is capable of transesterifying HBO into biodiesel

  5. Promotion of renewable energy to mitigate impact of heavy use of carbon energy on society and climate change in Central Sub-Saharan Africa remote areas.

    Science.gov (United States)

    Kenfack, Joseph; Bignom, Blaise

    2015-04-01

    Sub-Saharan Africa owns important renewable energy potential and is still heavily using carbon energy. This is having a negative impact on the climate and on the environment. Given the local cost of carbon energy, the purchase power of people, the availability and the reserve of carbon energy in the area, this resource is being heavily used. This practice is harmful to the climate and is also resulting on poor effort to promote renewable energy in remote areas. The important renewable energy potential is still suffering from poor development. The purpose of this paper is among other things aiming at showing the rate of carbon energy use and its potential impact on climate and environment. We will also ensure that the renewable energy resources of Central Sub-Saharan Africa are known and are subject to be used optimally to help mitigate climate change. After showing some negative impacts of carbon energy used in the area, the work also suggests actions to promote and sustain the development of renewable energy. Based on the knowledge of the Central African energy sector, this paper will identify actions for reduce access to carbon energy and improved access to sustainable, friendly, affordable energy services to users as well as a significant improvement of energy infrastructure and the promotion of energy efficiency. We will show all type of carbon energy used, the potential for solar, biomass and hydro while showing where available the level of development. After a swot analysis of the situation, identified obstacles for the promotion of clean energy will be targeted. Finally, suggestions will be made to help the region develop a vision aiming at developing good clean energy policy to increase the status of renewable energy and better contribute to fight against climate change. Cameroon case study will be examined as illustration. Analysis will be made from data collected in the field. |End Text|

  6. Identification of the Entner-Doudoroff pathway in an antibiotic-producing actinomycete species

    DEFF Research Database (Denmark)

    Gunnarsson, Nina; Mortensen, Uffe Hasbro; Sosio, M.;

    2004-01-01

    The metabolic network of the central carbon metabolism represents the backbone of cellular metabolism and provides the precursors and cofactors required for synthesis of secondary metabolites. It is therefore pivotal to map the operating metabolic network in the central carbon metabolism in order...... to design metabolic engineering strategies towards construction of more efficient producers of specific metabolites. In this context, methods that allow rapid and reliable mapping of the central carbon metabolism are valuable. In the present study, a C-13 labelling-based method was used to identify...... the primary metabolic pathways of the poorly characterized antibiotic-producing actinomycete Nonomuraea sp. ATCC 39727. Surprisingly, it was found that Nonomuraea sp. ATCC 39272 predominantly metabolizes glucose via the Entner-Doudoroff (ED) pathway. This represents the first time that the ED pathway has been...

  7. Carbon and nitrogen allocations in corn grown in Central and Northeast China:different responses to fertilization treatments

    Institute of Scientific and Technical Information of China (English)

    MIAO Hui-tian; L Jia-long; XU Ming-gang; ZHANG Wen-ju; HUANG Shao-min; PENG Chang; CHEN Li-ming

    2015-01-01

    In order to reveal the impact of various fertilization strategies on carbon (C) and nitrogen (N) accumulation and al ocation in corn (Zea mays L.), corn was grown in the ifelds where continuous fertilization management had been lasted about 18 years at two sites located in Central and Northeast China (Zhengzhou and Gongzhuling), and biomass C and N contents in different organs of corn at harvest were analyzed. The fertilization treatments included non-fertilizer (control), chemical fertilizers of either nitrogen (N), or nitrogen and phosphorus (NP), or phosphorus and potassium (PK), or nitrogen, phospho-rus and potassium (NPK), NPK plus manure (NPKM), 150%of the NPKM (1.5NPKM), and NPK plus straw (NPKS). The results showed that accumulated C in aboveground ranged from 2 550–5 630 kg ha–1 in the control treatment to 9 300–9 610 kg ha–1 in the NPKM treatment, of which 57–67%and 43–50%were al ocated in the non-grain organs, respectively. Accumulated N in aboveground ranged from 44.8–55.2 kg ha–1 in the control treatment to 211–222 kg ha–1 in the NPKM treatment, of which 35–48% and 33–44% were al ocated in the non-grain parts, respectively. C al ocated to stem and leaf for the PK treatment was 65 and 49%higher than that for the NPKM treatment at the both sites, respectively, while N al ocated to the organs for the PK treatment was 18 and 6%higher than that for the NPKM treatment, respectively. This study demonstrated that responses of C and N al ocation in corn to fertilization strategies were different, and C al ocation was more sensitive to fertilization treatments than N al ocation in the area.

  8. Implications of floristic and environmental variation for carbon cycle dynamics in boreal forest ecosystems of central Canada

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Zicheng; Apps, M.J.; Bhatti, J.S. [Canadan Forest Service, Edmonton (Canada). Northern Forestry Centre

    2002-06-01

    Species composition, detritus, and soil data from 97 boreal forest stands along a transect in central Canada were analysed using Correspondence Analysis to determine the dominant environmental/site variables that differentiate these forest stands. Picea mariana stands were densely clustered together on the understorey DCA plot, suggesting a consistent understorey species composition (feather mosses and Ericaceae), whereas Populus tremuloides stands had the most diverse understorey species composition (ca. 30 species, mostly shrubs and herbs). Pinus banksiana stands had several characteristic species of reindeer lichens (Cladina spp.), but saplings and Pinus seedlings were rare. Although climatic variables showed large variation along the transect, the CCA results indicated that site conditions are more important in determining species composition and differentiating the stand types. Forest floor characteristics (litter and humus layer, woody debris, and drainage) appear to be among the most important site variables. Stands of Picea had significantly higher average carbon (C) densities in the combined litter and humus layer (43,530 kg-C/ha) than either Populus (25,500 kg-C/ha) or Pinus (19,400 kg-C/ha). The thick surface organic layer in lowland Picea stands plays an important role in regulating soil temperature and moisture, and organic-matter decomposition, which in turn affect the ecosystem C-dynamics. During forest succession after a stand-replacing disturbance (e.g. fires), tree biomass and surface organic layer thickness increase in all stand types as forests recover; however, woody biomass detritus first decreases and then increases after ca. 80 yr. Soil C densities show slight decrease with ages in Populus stands, but increase in other stand types. These results indicate the complex C-transfer processes among different components (tree biomass, detritus, forest floor, and soil) of boreal ecosystems at various stages of succession.

  9. Do the Images of Neuronal Pathways in the Human Central Nervous System Show Feed-back? A Comparative Study in Fifteen Countries.

    Science.gov (United States)

    Clement, Pierre; Mouelhi, Lassaad; Kochkar, Momahed; Valanides, Nicos; Nisiforou, Olia; Thiaw, Seyni Mame; Ndiaye, Valdiodio; Jeanbart, Paula; Horvath, Daniel; Ferreira, Claudia; Carvalho, Graca S.

    2010-01-01

    In the human brain, the neuronal pathways are networks which support our learning, memory and thought, and which work with permanent feedback. However, only 19% of illustrations of these neuronal pathways, in the 55 analysed school textbooks coming from 15 countries, were showing feedbacks. The neuronal pathways related to movements were generally…

  10. 动物食欲调节的中枢信号通路%Central Appetite-Regulating Signaling Pathways in Animals

    Institute of Scientific and Technical Information of China (English)

    刘磊; 宋志刚

    2012-01-01

    Hypothalamus is the center of appetite regulation in animals, which integrates the peripheral and central signals to generate satiety or hunger. 5'-AMP-activated protein kinase( AMPK) and mammalian target of rapamycin (mTOR) are the signals found recently in the network of food or feed intake regulation in the hypothalamus. The pathways of AMPK-ACC-CPT1, UCP2-FOXOl-pCREB, PBK-Akt-mTOR and mTOR-4EBPl/p70S6K-NPY/AgRP are the most important ones. AMPK and mTOR might cross talk in the way of AMPK-TSC-mTOR, the gene expression of sterol regulatory element-binding proteins (SREBP) and the activity of UNC-51-like kinase (Ulkl). These signaling pathways respond to the signal transmission of nutrients and hormones to the hypothalamus, and regulate the expression of the anorexic or orexigenic peptides, and finally regulate the animal appetite. [Chinese Journal of Animal Nutrition, 2012, 24(2) :226-231]%下丘脑是动物食欲调节的中枢,外周食欲信号在下丘脑中经食欲调节网络整合,产生饱感或饥饿.其中,以5’-磷酸腺苷激活的蛋白激酶(AMPK)调控位点上的AMPK-ACC-CPT1和UCP2-FOXO1 -pCREB信号通路以及雷帕霉素靶蛋白(mTOR)调控位点上的PI3 K-Akt-mTOR和mTOR-4 EBP1/p70S6K-NPY/AgRP信号通路尤为重要.AMPK和mTOR在AMPK-TSC-mTOR通路、固醇类调节因子绑定蛋白(SREBP)基因表达和吞噬启动激酶(Ulk1)活性通路上存在互作.外周营养和能量信号传输到下丘脑后,经过这些网络的传输和分析,作用于下丘脑中的食欲相关肽,最终调控动物的采食行为.

  11. Diverse and uneven pathways towards transition to low carbon development: The case of diffusion of solar PV technology in China

    OpenAIRE

    Iizuka, M.

    2014-01-01

    Transition towards low carbon development (LCD) is an urgent challenge for the global community. As increased economic activities usually result in more carbon emissions, this challenge is particularly crucial for rapidly growing emerging countries. For these countries, reducing carbon emissions means taking one or more of the following actions: (1) reducing energy intensity; (2) increasing the use of renewable energy; and (3) introducing systemic change. The above actions call for a strong r...

  12. Burial fluxes and sources of organic carbon in sediments of the central Yellow Sea mud area over the past 200 years

    Institute of Scientific and Technical Information of China (English)

    YANG Shu; YANG Qian; LIU Sai; CAI Deling; QU Keming; SUN Yao

    2015-01-01

    Long-term changes of composition, sources and burial fluxes of TOC (total organic carbon) in sediments of the central Yellow Sea mud area and their possible affecting factors are discussed in this paper. Firstly, similarity analysis is employed to confirm that the carbon burial features resulted from two collected cores are typical in the central Yellow Sea mud area where YSWC (Yellow Sea Warm Current) is prevalent. On this basis, the burial flux of TOC here was considered to be 235.5–488.4 μmol/(cm2∙a) since the first industrial revolution, accounting for about 70%–90% among burial fluxes of TC (total carbon) in the sediments. Compared TOC/TC ratio in the two cores with that in other marine sediments worldwide, we suggest that the growth of calcareous/non-calcareous organisms and dissolution of IC (inorganic carbon) are important factors controlling the TOC/TC ratio in sediment. Results of two-end mixed model based onδ13C data indicate that marine-derived organic carbon (OCa) is the main part among total burial organic carbon which accounts for a ratio over 85%. Due to the high TOC/TC ratio in the two cores, TC in the sediments also mainly exists as OCa, and the proportion of OCa is about 60%–80%. Away from the shore and relatively high primary production in upper waters are the main reasons that OCa is predominant among all burial OC in sediments of the central Yellow Sea mud area. Burial of OC in this mud area is probably mainly influenced by the human activities. Although the economic development during the late 19th century caused by the first industrial revolution in China did not obviously increase the TOC burial fluxes in the sediments, the rise of industry and agriculture after the founding of new China has clearly increased the TOC burial flux since 1950s. Otherwise, we also realize that among TC burial fluxes, TIC account for about 10%–30% in sediments of the central Yellow Sea mud area, so its burial could not be simply ignored here

  13. Record of carbonate preservation and the Mid-Brunhes climatic shift from a seamount top with low sedimentation rates in the Central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Nath, B.N.; Sijinkumar, A.V.; Borole, D.V.; Gupta, S.M.; Mergulhao, L.P.; Mascarenhas-Pereira, M.B.L.; Ramaswamy, V.; Guptha, M.V.S.; Possnert, G.; Aldahan, A.; Khadge, N.H.; Sharma, R.

    ): palaeoceanographic implications. Paleogeography, Paleoclimatology, Paleoecology 196, 409-426. Flynn, W. W. 1968: The determination of low levels of polonium-210 in environmental samples. Analytica Chimica Acta 43, 221-227. Folk, R. L. 1968: Petrology....42(3); 2013; 762-778 Record of carbonate preservation and Mid-Brunhes climatic shift from a seamount top with low sedimentation rates in the Central Indian Basin BEJUGAM NAGENDER NATH, ADUKKAM V. SIJINKUMAR, DNYANDEV V. BOROLE, SHYAM M. GUPTA...

  14. A MicroRNA-Mediated Insulin Signaling Pathway Regulates the Toxicity of Multi-Walled Carbon Nanotubes in Nematode Caenorhabditis elegans

    Science.gov (United States)

    Zhao, Yunli; Yang, Junnian; Wang, Dayong

    2016-03-01

    The underlying mechanisms for functions of microRNAs (miRNAs) in regulating toxicity of nanomaterials are largely unclear. Using Illumina HiSeqTM 2000 sequencing technique, we obtained the dysregulated mRNA profiling in multi-walled carbon nanotubes (MWCNTs) exposed nematodes. Some dysregulated genes encode insulin signaling pathway. Genetic experiments confirmed the functions of these dysregulated genes in regulating MWCNTs toxicity. In the insulin signaling pathway, DAF-2/insulin receptor regulated MWCNTs toxicity by suppressing function of DAF-16/FOXO transcription factor. Moreover, we raised a miRNAs-mRNAs network involved in the control of MWCNTs toxicity. In this network, mir-355 might regulate MWCNTs toxicity by inhibiting functions of its targeted gene of daf-2, suggesting that mir-355 may regulate functions of the entire insulin signaling pathway by acting as an upregulator of DAF-2, the initiator of insulin signaling pathway, in MWCNTs exposed nematodes. Our results provides highlight on understanding the crucial role of miRNAs in regulating toxicity of nanomaterials in organisms.

  15. The effects of folate intake on DNA and single-carbon pathway metabolism in the fruit fly Drosophila melanogaster compared to mammals.

    Science.gov (United States)

    Blatch, Sydella A; Stabler, Sally P; Harrison, Jon F

    2015-11-01

    Mechanisms of vitamin function in non-mammals are poorly understood, despite being essential for development. Folate and cobalamin are B-vitamin cofactors with overlapping roles in transferring various single-carbon units. In mammals, one or both is needed for nucleotide synthesis, DNA methylation, amino acid conversions and other reactions. However, there has been little investigation of the response to folate or cobalamin in insects. Here, we manipulated folate intake and potentially cobalamin levels in the fruit fly Drosophila melanogaster with chemically-defined diets, an antibiotic to reduce bacterially-derived vitamins, and the folate-interfering pharmaceutical methotrexate, to see if single-carbon metabolites and DNA synthesis rates would be affected. We found that similar to mammals with low folate intake, fruit fly larvae had significantly slower growth and DNA synthesis rates. But changes to single carbon-metabolites did not mirror that of mammals with abnormal folate or given MTX. Five of the nine metabolites measured were not significantly affected (methionine, serine, glycine, methylglycine, and dimethylglycine) and three (cystathionine, methylgycine, and methylmalonic acid) were only decreased in larvae consuming methotrexate. Metabolites expected to be elevated if flies used cobalamin from microbial symbionts were not affected by dietary sulfaquinoxaline. Our data support the role of folate in nucleotide synthesis in D. melanogaster and that microbial symbionts provide functioning folates. We could not confirm how folate intake affects single carbon pathway metabolites, nor whether Drososphila use microbially-derived cobalamin. Further work should explore which cofactors are used in fruit flies in these important and potentially novel pathways.

  16. The effects of folate intake on DNA and single-carbon pathway metabolism in the fruit fly Drosophila melanogaster compared to mammals.

    Science.gov (United States)

    Blatch, Sydella A; Stabler, Sally P; Harrison, Jon F

    2015-11-01

    Mechanisms of vitamin function in non-mammals are poorly understood, despite being essential for development. Folate and cobalamin are B-vitamin cofactors with overlapping roles in transferring various single-carbon units. In mammals, one or both is needed for nucleotide synthesis, DNA methylation, amino acid conversions and other reactions. However, there has been little investigation of the response to folate or cobalamin in insects. Here, we manipulated folate intake and potentially cobalamin levels in the fruit fly Drosophila melanogaster with chemically-defined diets, an antibiotic to reduce bacterially-derived vitamins, and the folate-interfering pharmaceutical methotrexate, to see if single-carbon metabolites and DNA synthesis rates would be affected. We found that similar to mammals with low folate intake, fruit fly larvae had significantly slower growth and DNA synthesis rates. But changes to single carbon-metabolites did not mirror that of mammals with abnormal folate or given MTX. Five of the nine metabolites measured were not significantly affected (methionine, serine, glycine, methylglycine, and dimethylglycine) and three (cystathionine, methylgycine, and methylmalonic acid) were only decreased in larvae consuming methotrexate. Metabolites expected to be elevated if flies used cobalamin from microbial symbionts were not affected by dietary sulfaquinoxaline. Our data support the role of folate in nucleotide synthesis in D. melanogaster and that microbial symbionts provide functioning folates. We could not confirm how folate intake affects single carbon pathway metabolites, nor whether Drososphila use microbially-derived cobalamin. Further work should explore which cofactors are used in fruit flies in these important and potentially novel pathways. PMID:26219578

  17. Transport of dissolved organic carbon from soil to surface water: Identification and modeling of pathways and controlling factors

    OpenAIRE

    Van Gaelen, Nele

    2016-01-01

    Dissolved organic carbon (DOC) in the surface water is an important component of the global carbon cycle. Due to its active and mobile nature, it affects aquatic ecosystems in several ways and plays a significant role in the cycling and distribution of carbon within and between ecosystems. Although the estimated annual flux of DOC from the land to the oceans is ±0.4 Pg C/year, almost half the current net terrestrial uptake of ±0.9 Pg C/year, the factors controlling the transport of DOC from t...

  18. 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

  19. Mass concentrations of black carbon measured by four instruments in the middle of Central East China in June 2006

    Directory of Open Access Journals (Sweden)

    Y. Kanaya

    2008-08-01

    Full Text Available Mass concentrations of black carbon (BC were determined in June 2006 at the top of Mount Tai (36.26° N, 117.11° E, 1534 m a.s.l., located in the middle of Central East China, using four different instruments: a multi-angle absorption photometer (5012 MAAP, Thermo, a particle soot absorption photometer (PSAP, Radiance Research, an ECOC semi-continuous analyzer (Sunset Laboratory and an Aethalometer (AE-21, Magee Scientific. High correlation coefficients (R2>0.88 were obtained between the measurements of the BC mass concentrations by the different instruments. From the range of the slopes of the linear least-square fittings, we concluded that the BC concentrations regionally-representative of the area were measured in a range with a maximum-to-minimum ratio of 1.5 (an exception was that the BC (PM2.5 concentrations derived from MAAP were ~2 times higher than the optical measurements (PM2.5 derived from the ECOC analyzer. This range is significant, but is still sufficiently narrow to better constrain the large and highly uncertain emission rate of BC from China. In detail, two optical instruments (the MAAP instrument and the PSAP instrument equipped with a heated inlet (400°C tended to give higher concentrations than the thermal EC concentrations observed by the ECOC analyzer. The ratios of optical BC to thermal EC showed a positive correlation with the OC/EC ratio reported by the ECOC analyzer, suggesting two possibilities. One is that the optical instruments overestimated BC concentrations in spite of careful cancellation of the scattering effect in the MAAP instrument and the expected evaporation of volatile species by heating the inlet of the PSAP instrument. The other is that the determined split points between OC and EC were too late when a large amount of OC underwent charring during the analysis, resulting in an underestimation of EC by the ECOC analyzer. High ratios of optical BC to thermal EC

  20. World-Economy Centrality and Carbon Dioxide Emissions: A New Look at the Position in the Capitalist World-System and Environmental Pollution

    Directory of Open Access Journals (Sweden)

    Paul Prew

    2015-08-01

    Full Text Available With the ever-growing concern of climate change, much attention has been paid to the factors driving carbon dioxide emissions. Previous research in the World-Systems perspective has identified a relationship between carbon dioxide emissions and position in the world-economy. This study intends to build on the previous research by developing a new, more parsimonious indicator of World-System position based on Immanuel Wallerstein’s theoretical concepts of incorporation and core-periphery processes. The new World-System indicator is derived from the centrality measure in network analysis based on import data from the International Monetary Fund’s Direction of Trade Statistics. Based on the theoretical concepts of core-periphery processes, carbon dioxide emissions are predicted to rise based on the predominance of energy-intensive, high-technology, core processes within the nation. The results tend to demonstrate a strong relationship between carbon dioxide emissions and position in the world-economy, and the new World-System position indicator is more strongly related with carbon dioxide emissions than Gross Domestic Product per capita.

  1. Subaerial exposure and drowning processes in a carbonate platform during the Mesozoic Tethyan rifting: The case of the Jurassic succession of Western Sicily (central Mediterranean)

    Science.gov (United States)

    Sulli, A.; Interbartolo, F.

    2016-01-01

    The Liassic carbonate platform succession outcropping at Monte Maranfusa (central Western Sicily) consists of a shallowing-upward sequence of peritidal carbonates, with Jurassic to Paleogene pelagic limestone and siliciclastic Tertiary covers above. The cyclic sequences of subtidal wackestones/packstones, intertidal microcrystalline carbonates with bird's-eye pores, and supratidal bioclastic grainstones are interbedded with dark layers of the following composition: 1) dark-gray, compact, and well-cemented limestone with blackish clasts, interpreted as calcretes (a type of carbonate soil) and 2) reddish calcite laminae, deformed by elongated cavities, filled with vadose silt, interpreted as paleokarst. This succession is crossed by almost vertical faults, of the Late Liassic to Miocene, which often coincides with neptunian dykes, filled by several generations of Toarcian-Early Miocene pelagic sediments. Another system of dykes, known as neptunian sills, filled by injected Upper Lias-Dogger pelagic sediments, lies parallel to the stratification. The parallel dykes were caused by the flexure of the platform during the Jurassic and presumably by a planar slip in the carbonate rocks, whereas neptunian dykes are caused by faulting episodes. Here, we present evidence that the dark layers in the Liassic succession of Monte Maranfusa, previously described by many authors only as parallel dykes, can actually be interpreted as a) neptunian sills, b) pedogenic calcretes, and c) paleospeleothems. Therefore, we found evidence of exposure/flooding intervals in the evolution of the carbonate platform during the Liassic, linked to different pulses in both the subsidence/tectonic activity and the sea-level oscillations. At the top, Fe-Mn crusts (hardgrounds) seal the carbonate platform succession, which is in turn overlain by condensed pelagic deposits, confirming its drowning during rifting processes.

  2. Impact of total organic carbon (in sediments) and dissolved organic carbon (in overlying water column) on Hg sequestration by coastal sediments from the central east coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Chakrabortya, P.; Sharma, B.M.; Babu, P.V.R.; Yao, K.M.; Jaychandran, S.

          1.0 Introduction Mercury (Hg) has received a worldwide attention due to its significant global adverse impact on both environment and human health (Boening, 2000; Ratcliffe et al., 1996; Wolfe et al., 2009). Due to its high toxicity... of dissolved organic carbon and salinity on bioavailability of mercury. Applied and Environmental Microbiology, 63, 4267–4271. Bengtsson, G., Picado, F., 2008. Mercury sorption to sediments: Dependence on grain size, dissolved organic carbon, and suspended...

  3. POSSIBLE LATE MIDDLE ORDOVICIAN ORGANIC CARBON ISOTOPE EXCURSION: EVIDENCE FROM ORDOVICIAN OILS AND HYDROCARBON SOURCE ROCKS, MID-CONTINENT AND EAST-CENTRAL UNITED STATES.

    Science.gov (United States)

    Hatch, Joseph R.; Jacobson, Stephen R.; Witzke, Brian J.; Risatti, J. Bruno; Anders, Donald E.; Watney, W. Lynn; Newell, K. David; Vuletich, April K.

    1987-01-01

    Oils generated by Middle Ordovician rocks are found throughout the Mid-Continent and east-central regions of the United States. Gas chromatographic characteristics of these oils include a relatively high abundance of n-alkanes with carbon numbers less than 20, a strong predominance of odd-numbered n-alkanes between C//1//0 and C//2//0, and relatively small amounts of branched and cyclic alkanes. The wide ranges in delta **1**3C for oils and rock extracts reflect a major, positive excursion(s) in organic matter delta **1**3C in late Middle Ordovician rocks. This excursion has at least regional significance in that it can be documented in sections 480 mi apart in south-central Kansas and eastern Iowa. The distance may be as much as 930 mi. The parallel shifts in organic and carbonate delta **1**3C in core samples from 1 E. M. Greene well, Washington County, Iowa, imply changes in the isotope composition of the ocean-atmosphere carbon reservoir. These and other aspects of the subject are discussed.

  4. Zero Carbon Latin America - A pathway for net decarbonisation of the regional economy by mid-century

    DEFF Research Database (Denmark)

    Vergara, Walter; Fenhann, Jørgen Villy; Schletz, Marco Christian

    The objective of the analysis presented in this report is to visualize a pathway for complete decarbonisation of the Latin American and the Caribbean (LAC) regional economy by mid-century. This is achieved through a review of specific sector-wide actions, within a foreseeable technology and econo...

  5. Fluxes and 13C isotopic composition of dissolved carbon and pathways of methanogenesis in a fen soil exposed to experimental drought

    Directory of Open Access Journals (Sweden)

    C. Blodau

    2008-10-01

    Full Text Available Peatlands contain a carbon stock of global concern and significantly contribute to the global methane burden. The impact of drought and rewetting on carbon cycling in peatland ecosystems is thus currently debated. We studied the impact of experimental drought and rewetting on intact monoliths from a temperate fen over a period of ~300 days, using a permanently wet treatment and two treatments undergoing drought for 50 days. In one of the mesocosms, vegetation had been removed. Net production of CH4 was calculated from mass balances in the peat and emission using static chamber measurements. Results were compared to 13C isotope budgets of CO2 and CH4 and energy yields of acetoclastic and hydrogenotrophic methanogenesis. Drought retarded methane production after rewetting for days to weeks and promoted methanotrophic activity. Based on isotope and flux budgets, aerobic soil respiration contributed 32–96% in the wet treatment and 86–99% in the other treatments. Drying and rewetting did not shift methanogenic pathways according to δ13C ratios of CH4 and CO2. Although δ13C ratios indicated a prevalence of hydrogenotrophic methanogenesis, free energies of this process were small and often positive on the horizon scale. This suggests that methane was produced very locally. Fresh plant-derived carbon input apparently supported respiration in the rhizosphere and sustained methanogenesis in the unsaturated zone, according to a 13C-CO2 labelling experiment. The study documents that drying and rewetting in a rich fen soil may have little effect on methanogenic pathways, but result in rapid shifts between methanogenesis and methanotrophy. Such shifts may be promoted by roots and soil heterogeneity, as hydrogenotrophic methanogenesis occurred locally even when conditions were not conducive for this process in the bulk peat.

  6. An assessment on in-vehicle concentration of carbon monoxide for taxis in central business district of Tehran

    Directory of Open Access Journals (Sweden)

    Nabi ollah Mansouri

    2013-01-01

    Full Text Available Background and Aim: Carbon monoxide is colorless and odorless gas. In high concentrations, CO is deadly poisonous and in low concentrations can cause fatigue, headache, dizziness and seizures. Carbon monoxide has a high affinity to combines hemoglobin which can decrease oxygen capacity in blood. To address this problem, human body begins to produce red blood cells, this can increases blood viscosity and thus increase diseases such as stroke and heart attack. About 60 percent of total emissions of carbon monoxide are associated automobile exhaust. In this study, concentration of carbon monoxide has been measured in the cabin space of taxis in high-traffic areas of Tehran.Materials and Methods: This study is carried out in spring and summer 2011. Concentrations of carbon monoxide in different types of taxi cabin space (Peugeot, Samand, Pride and Peykan were measured by carbon monoxide meter Q RAE 2 models in different conditions of motion: high speed (over 45 kilometers per hour, low speed (15-30 kilometers per hour and stop (0 kilometers per hour. Results: Results showed that concentration of carbon monoxide in old vehicles (above 10 years is more than three times compared to new vehicles and outdoor. In addition, according to the measured values, at low speeds, values of CO rapidly increased, so that in speeds of less than 15 km, values of CO go beyond standard values (9 ppm.Conclusion: Results show that the mean value of the measured concentration of carbon monoxide is higher than amounts recommended by WHO and EPA and local authorities such as Air Quality Control Organization of Tehran. Concentrations observed in this study are up to 40 more than results of a study by German researchers in summer 1995 and winter 1996.

  7. Hepatic Progenitor Cells Contribute to the Progression of 2-Acetylaminofluorene/Carbon Tetrachloride-Induced Cirrhosis via the Non-Canonical Wnt Pathway.

    Directory of Open Access Journals (Sweden)

    Jiamei Chen

    Full Text Available Hepatic progenitor cells (HPCs appear to play an important role in chronic liver injury. In this study, cirrhosis was induced in F-344 rats (n = 32 via subcutaneous injection of 50% carbon tetrachloride (CCl4 twice a week for 8 weeks. Then, 30% CCl4 was administered in conjunction with intragastric 2-acetylaminofluorine (2-AAF for 4 weeks to induce activation of HPCs. WB-F344 cells were used to provide direct evidence for differentiation of HPCs to myofibroblasts. The results showed that after administration of 2-AAF, the hydroxyproline content and the expressions of α-SMA, Col I, Col IV, TGF-β1, CD68, TNF-α, CK19 and OV6 were significantly increased. OV6 and α-SMA were largely co-expressed in fibrous septum and the expressions of Wnt5b, frizzled2, frizzled3 and frizzled6 were markedly increased, while β-catenin expression was not statistically different among the different groups. Consistent with the above results, WB-F344 cells, treated with TGF-β1 in vitro, differentiated into myofibroblasts and α-SMA, Col I, Col IV, Wnt5b and frizzled2 expressions were significantly increased, while β-catenin expression was decreased. After blocking the non-canonical Wnt pathway via WIF-1, the Wnt5b level was down regulated, and α-SMA and F-actin expressions were significantly decreased in the WIF-1-treated cells. In conclusion, these results indicate that HPCs appear to differentiate into myofibroblasts and exhibit a profibrotic effect in progressive cirrhosis via activation of the non-canonical Wnt pathway. Blocking the non-canonical Wnt pathway can inhibit the differentiation of HPCs into myofibroblasts, suggesting that blocking this pathway and changing the fate of differentiated HPCs may be a potential treatment for cirrhosis.

  8. Hepatic Progenitor Cells Contribute to the Progression of 2-Acetylaminofluorene/Carbon Tetrachloride-Induced Cirrhosis via the Non-Canonical Wnt Pathway.

    Science.gov (United States)

    Chen, Jiamei; Zhang, Xiao; Xu, Ying; Li, Xuewei; Ren, Shuang; Zhou, Yaning; Duan, Yuyou; Zern, Mark; Zhang, Hua; Chen, Gaofeng; Liu, Chenghai; Mu, Yongping; Liu, Ping

    2015-01-01

    Hepatic progenitor cells (HPCs) appear to play an important role in chronic liver injury. In this study, cirrhosis was induced in F-344 rats (n = 32) via subcutaneous injection of 50% carbon tetrachloride (CCl4) twice a week for 8 weeks. Then, 30% CCl4 was administered in conjunction with intragastric 2-acetylaminofluorine (2-AAF) for 4 weeks to induce activation of HPCs. WB-F344 cells were used to provide direct evidence for differentiation of HPCs to myofibroblasts. The results showed that after administration of 2-AAF, the hydroxyproline content and the expressions of α-SMA, Col I, Col IV, TGF-β1, CD68, TNF-α, CK19 and OV6 were significantly increased. OV6 and α-SMA were largely co-expressed in fibrous septum and the expressions of Wnt5b, frizzled2, frizzled3 and frizzled6 were markedly increased, while β-catenin expression was not statistically different among the different groups. Consistent with the above results, WB-F344 cells, treated with TGF-β1 in vitro, differentiated into myofibroblasts and α-SMA, Col I, Col IV, Wnt5b and frizzled2 expressions were significantly increased, while β-catenin expression was decreased. After blocking the non-canonical Wnt pathway via WIF-1, the Wnt5b level was down regulated, and α-SMA and F-actin expressions were significantly decreased in the WIF-1-treated cells. In conclusion, these results indicate that HPCs appear to differentiate into myofibroblasts and exhibit a profibrotic effect in progressive cirrhosis via activation of the non-canonical Wnt pathway. Blocking the non-canonical Wnt pathway can inhibit the differentiation of HPCs into myofibroblasts, suggesting that blocking this pathway and changing the fate of differentiated HPCs may be a potential treatment for cirrhosis. PMID:26087010

  9. Five phosphonate operon gene products as components of a multi-subunit complex of the carbon-phosphorus lyase pathway

    DEFF Research Database (Denmark)

    Jochimsen, Bjarne; Lolle, Signe; McSorley, Fern R.;

    2011-01-01

    Organophosphonate utilization by Escherichia coli requires the 14 cistrons of the phnCDEFGHIJKLMNOP operon, of which the carbon-phosphorus lyase has been postulated to consist of the seven polypeptides specified by phnG to phnM. A 5,660-bp DNA fragment encompassing phnGHIJKLM is cloned, followed ...

  10. The influence of climate cycles on the water regime and carbonate profile in chernozems of Central European Russia and adjacent territories

    Science.gov (United States)

    Bazykina, G. S.; Ovechkin, S. V.

    2016-04-01

    The influence of long-term "dry" and "wet" climatic cycles on the water regime, hydrological parameters, and carbonate profiles of chernozems in Central European Russia and adjacent territories was studied. The hydrological and carbonate profiles were found to change during the wet cycle. However, the upper part of the hydrological profile is basically unchanging, whereas in its lower part, the number of hydrological horizons and contrast in their moistening decrease in the forest-steppe chernozems and increase in the steppe chernozems. The frequency of through wetting of chernozems increases during the wet cycles. The vertical lithological heterogeneity of the parent material affects the soil moisture status. In the wet climatic cycle, the moisture content above the lithological contact increases resulting in the development of the features of soil hydromorphism. In the carbonate profile, the character of pedofeatures is changing: some carbonate neoformations disappear, while the other ones develop. Possible variations of the periodically percolative water regime were revealed in chernozems. The classification of water regime proposed by A.A. Rode may be updated based on the data obtained during the dry climatic cycle. Rode's hypothesis about cyclic variations in the soil water regime is confirmed.

  11. Spring bloom community change modifies carbon pathways and C : N : P : Chl a stoichiometry of coastal material fluxes

    Directory of Open Access Journals (Sweden)

    K. Spilling

    2014-08-01

    Full Text Available Diatoms and dinoflagellates are major bloom-forming phytoplankton groups competing for resources in the oceans and coastal seas. Recent evidence suggests that their competition is significantly affected by climatic factors under ongoing change, modifying especially the conditions for cold-water, spring bloom communities in temperate and arctic regions. We investigated the effects of phytoplankton community composition on spring bloom carbon flows and nutrient stoichiometry in multi-year mesocosm experiments. Comparison of differing communities showed that community structure significantly affected C accumulation parameters, with highest particulate organic carbon (POC build-up and dissolved organic carbon (DOC release in diatom-dominated communities. In terms of inorganic nutrient drawdown and bloom accumulation phase, the dominating groups behaved as functional surrogates. Dominance patterns, however, significantly affected C : N : P : Chl a ratios over the whole bloom event: when diatoms were dominant, these ratios increased compared to dinoflagellate dominance or mixed communities. Diatom-dominated communities sequestered carbon up to 3.6-fold higher than the expectation based on the Redfield ratio, and 2-fold higher compared to dinoflagellate dominance. To our knowledge, this is the first experimental report of consequences of climatically driven shifts in phytoplankton dominance patterns for carbon sequestration and related biogeochemical cycles in coastal seas. Our results also highlight the need for remote sensing technologies with taxonomical resolution, as the C : Chl a ratio was strongly dependent on community composition and bloom stage. Climate-driven changes in phytoplankton dominance patterns will have far-reaching consequences for major biogeochemical cycles and need to be considered in climate change scenarios for marine systems.

  12. Brain architecture of the largest living land arthropod, the Giant Robber Crab Birgus latro (Crustacea, Anomura, Coenobitidae: evidence for a prominent central olfactory pathway?

    Directory of Open Access Journals (Sweden)

    Krieger Jakob

    2010-09-01

    suggest that B. latro has visual and mechanosensory skills that are comparable to those of marine Crustacea. Conclusions In parallel to previous behavioral findings that B. latro has aerial olfaction, our results indicate that their central olfactory pathway is indeed most prominent. Similar findings from the closely related terrestrial hermit crab Coenobita clypeatus suggest that in Coenobitidae, olfaction is a major sensory modality processed by the brain, and that for these animals, exploring the olfactory landscape is vital for survival in their terrestrial habitat. Future studies on terrestrial members of other crustacean taxa such as Isopoda, Amphipoda, Astacida, and Brachyura will shed light on how frequently the establishment of an aerial sense of olfaction evolved in Crustacea during the transition from sea to land. Amounting to ca. 1,000,000, the numbers of interneurons that analyse the olfactory input in B. latro brains surpasses that in other terrestrial arthropods, as e.g. the honeybee Apis mellifera or the moth Manduca sexta, by two orders of magnitude suggesting that B. latro in fact is a land-living arthropod that has devoted a substantial amount of nervous tissue to the sense of smell.

  13. Structure of PhnP: a phosphodiesterase of the carbon-phosphorous lyase pathway for phosphonate degradation

    DEFF Research Database (Denmark)

    Podzelinska, Kateryna; He, Shu-Mei; Wathier, Matthew;

    2009-01-01

    Carbon-phosphorus lyase is a multienzyme system encoded by the phn operon that enables bacteria to metabolize organophosphonates when the preferred nutrient, inorganic phosphate, is scarce. One of the enzymes encoded by this operon, PhnP, is predicted by sequence homology to be a metal-dependent ......Carbon-phosphorus lyase is a multienzyme system encoded by the phn operon that enables bacteria to metabolize organophosphonates when the preferred nutrient, inorganic phosphate, is scarce. One of the enzymes encoded by this operon, PhnP, is predicted by sequence homology to be a metal....... A second, remote Zn2+ binding site is also observed, composed of a set of cysteine and histidine residues that are strictly conserved in the PhnP family. This second metal ion site appears to stabilize a structural motif....

  14. Reservoir Characterization for CO2 Sequestration: Assessing the Potential of the Devonian Carbonate Nisku Formation of Central Alberta Caractérisation de réservoir en vue du stockage géologique de CO2 : évaluation du potentiel offert par les carbonates dévoniens de la formation de Nisku, en Alberta central

    OpenAIRE

    Eisinger C.; Jensen J

    2011-01-01

    The Wabamun Lake area of Central Alberta, Canada includes several large CO2 point source emitters, collectively producing more than 30 Mt annually. Previous studies established that deep saline aquifers beneath the Wabamun Lake area have good potential for the large-scale injection and storage of CO2. This study reports on the characterization of the Devonian carbonate Nisku Formation for evaluation as a CO2 repository. Major challenges for characterization included sparse well and seis...

  15. Carbon sequestration in Chir-Pine (Pinus roxburghii Sarg.) forests un-der various disturbance levels in Kumaun Central Himalaya

    Institute of Scientific and Technical Information of China (English)

    Harshit Pant; Ashish Tewari

    2014-01-01

    We studied variations in tree biomass and carbon sequestra-tion rates of Chir Pine (Pinus roxburghii. Sarg.) forest in three categories of forest disturbance, protected, moderately disturbed, and highly dis-turbed. In the first year, total biomass was 14.7 t⋅ha-1 in highly disturbed site, 94.46 t⋅ha-1 in moderately disturbed forest, and 112.0 t⋅ha-1 in pro-tected forest. The soil organic carbon in the top 20 cm of soil ranged from 0.63 to 1.2%. The total rate of carbon sequestration was 0.60 (t/ha)·a-1on the highly disturbed site, 1.03 (t/ha)·a-1 on the moderately disturbed site, and 4.3 (t/ha)·a-1 on the protected site.

  16. Metabolomic profile of glycolysis and the pentose phosphate pathway identifies the central role of glucose-6-phosphate dehydrogenase in clear cell-renal cell carcinoma.

    Science.gov (United States)

    Lucarelli, Giuseppe; Galleggiante, Vanessa; Rutigliano, Monica; Sanguedolce, Francesca; Cagiano, Simona; Bufo, Pantaleo; Lastilla, Gaetano; Maiorano, Eugenio; Ribatti, Domenico; Giglio, Andrea; Serino, Grazia; Vavallo, Antonio; Bettocchi, Carlo; Selvaggi, Francesco Paolo; Battaglia, Michele; Ditonno, Pasquale

    2015-05-30

    The analysis of cancer metabolome has shown that proliferating tumor cells require a large quantities of different nutrients in order to support their high rate of proliferation. In this study we analyzed the metabolic profile of glycolysis and the pentose phosphate pathway (PPP) in human clear cell-renal cell carcinoma (ccRCC) and evaluate the role of these pathways in sustaining cell proliferation, maintenance of NADPH levels, and production of reactive oxygen species (ROS). Metabolomic analysis showed a clear signature of increased glucose uptake and utilization in ccRCC tumor samples. Elevated levels of glucose-6-phosphate dehydrogenase (G6PDH) in association with higher levels of PPP-derived metabolites, suggested a prominent role of this pathway in RCC-associated metabolic alterations. G6PDH inhibition, caused a significant decrease in cancer cell survival, a decrease in NADPH levels, and an increased production of ROS, suggesting that the PPP plays an important role in the regulation of ccRCC redox homeostasis. Patients with high levels of glycolytic enzymes had reduced progression-free and cancer-specific survivals as compared to subjects with low levels. Our data suggest that oncogenic signaling pathways may promote ccRCC through rerouting the sugar metabolism. Blocking the flux through this pathway may serve as a novel therapeutic target. PMID:25945836

  17. Metabolomic profile of glycolysis and the pentose phosphate pathway identifies the central role of glucose-6-phosphate dehydrogenase in clear cell-renal cell carcinoma.

    Science.gov (United States)

    Lucarelli, Giuseppe; Galleggiante, Vanessa; Rutigliano, Monica; Sanguedolce, Francesca; Cagiano, Simona; Bufo, Pantaleo; Lastilla, Gaetano; Maiorano, Eugenio; Ribatti, Domenico; Giglio, Andrea; Serino, Grazia; Vavallo, Antonio; Bettocchi, Carlo; Selvaggi, Francesco Paolo; Battaglia, Michele; Ditonno, Pasquale

    2015-05-30

    The analysis of cancer metabolome has shown that proliferating tumor cells require a large quantities of different nutrients in order to support their high rate of proliferation. In this study we analyzed the metabolic profile of glycolysis and the pentose phosphate pathway (PPP) in human clear cell-renal cell carcinoma (ccRCC) and evaluate the role of these pathways in sustaining cell proliferation, maintenance of NADPH levels, and production of reactive oxygen species (ROS). Metabolomic analysis showed a clear signature of increased glucose uptake and utilization in ccRCC tumor samples. Elevated levels of glucose-6-phosphate dehydrogenase (G6PDH) in association with higher levels of PPP-derived metabolites, suggested a prominent role of this pathway in RCC-associated metabolic alterations. G6PDH inhibition, caused a significant decrease in cancer cell survival, a decrease in NADPH levels, and an increased production of ROS, suggesting that the PPP plays an important role in the regulation of ccRCC redox homeostasis. Patients with high levels of glycolytic enzymes had reduced progression-free and cancer-specific survivals as compared to subjects with low levels. Our data suggest that oncogenic signaling pathways may promote ccRCC through rerouting the sugar metabolism. Blocking the flux through this pathway may serve as a novel therapeutic target.

  18. Potentiation of glutamate release caused by delta—methrin and the possible mechanism associated with carbon monoxide pathway and protein kinase C

    Institute of Scientific and Technical Information of China (English)

    AiBM; LiuYG

    2002-01-01

    The acute neurotoxicity of delta-methrin is thought to be associated with the release of grutamate from synaptosomes in brain.However,the mechanism how delta-methrin enhances the glutamate release has still not been elucidated.Here we report that both carbon monoxide(CO) and the activator of protein kinase C(PKC),similarly to delta-methrin,potentiate the Ca2+-dependent glutamate release from rat cerebral cortical synaptosomes,otherwise,the release of glutamate is inhibited by zinc proporphyrin-9(ZnPP-9) and inhibitors of PKC or of protein kinase G(PKG).In addition,the inhibitors of ZnPP-9 PKC and PKG seem to weaken the enhancement of glutamate releas caused by delta-methrin.So,we conclude that CO signal transduction pathway and PKC mediate the glutamate release from synptosomes by delta-methrin.

  19. Regulation of Dual Glycolytic Pathways for Fructose Metabolism in Heterofermentative Lactobacillus panis PM1

    OpenAIRE

    Kang, Tae Sun; Korber, Darren R; Tanaka, Takuji

    2013-01-01

    Lactobacillus panis PM1 belongs to the group III heterofermentative lactobacilli that use the 6-phosphogluconate/phosphoketolase (6-PG/PK) pathway as their central metabolic pathway and are reportedly unable to grow on fructose as a sole carbon source. We isolated a variant PM1 strain capable of sporadic growth on fructose medium and observed its distinctive characteristics of fructose metabolism. The end product pattern was different from what is expected in typical group III lactobacilli us...

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

    Directory of Open Access Journals (Sweden)

    Usui Yuki

    2012-06-01

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

  1. Infrared spectral and carbon isotopic characteristics of micro- and macro-diamonds from the Panda kimberlite (Central Slave Craton, Canada)

    Science.gov (United States)

    Melton, G. L.; Stachel, T.; Stern, R. A.; Carlson, J.; Harris, J. W.

    2013-09-01

    One hundred and twenty-one micro-diamonds (Panda kimberlite (Ekati mine, Central Slave Craton, Canada) were analyzed for nitrogen content, nitrogen aggregation state (%B) and platelet and hydrogen peak areas (cm- 2). Micro-diamond nitrogen concentrations range from 2‰, but mostly vary by bearing metasomatic fluid/melt that isotopically evolves as it percolates upward through the lithosphere.

  2. REGIONAL EMISSIONS OF NITRIC OXIDE (NO) AND CARBON DIOXIDE (CO2) IN AGROECOSYSTEMS IN CENTRAL WEST REGION, BRAZIL.

    Science.gov (United States)

    The Central West Region in Brazil has been the focus of intense agricultural expansion since the 1970s and, nowadays, a large area of native cerrado has been converted to agricultural use. The expansion was accompanied by intensive use of fertilizer, irrigation and management pra...

  3. Comparison of carbon uptake estimates from forest inventory and Eddy-Covariance for a montane rainforest in central Sulawesi

    Science.gov (United States)

    Heimsch, Florian; Kreilein, Heiner; Rauf, Abdul; Knohl, Alexander

    2016-04-01

    Rainforests in general and montane rainforests in particular have rarely been studied over longer time periods. We aim to provide baseline information of a montane tropical forest's carbon uptake over time in order to quantify possible losses through land-use change. Thus we conducted a re-inventory of 22 10-year old forest inventory plots, giving us a rare opportunity to quantify carbon uptake over such a long time period by traditional methods. We discuss shortfalls of such techniques and why our estimate of 1.5 Mg/ha/a should be considered as the lower boundary and not the mean carbon uptake per year. At the same location as the inventory, CO2 fluxes were measured with the Eddy-Covariance technique. Measurements were conducted at 48m height with an LI 7500 open-path infrared gas analyser. We will compare carbon uptake estimates from these measurements to those of the more conventional inventory method and discuss, which factors are probably responsible for differences.

  4. Organic carbon isotope and molecular fossil records of vegetation evolution in central Loess Plateau since 450 kyr

    NARCIS (Netherlands)

    Zhou, Bin; Wali, Guzalnur; Peterse, Francien; Bird, Michael I.

    2016-01-01

    Significant uncertainties remain regarding the temporal evolution of natural vegetation during the Quaternary, and drivers of past vegetation change, on the Chinese Loess Plateau (CLP). This study presents analyses of total organic carbon isotopic composition (TOC) and n-alkane ratios (C31/C27) from

  5. LAND-USE CHANGE AND CARBON FLUX BETWEEN 1970S AND 1990S IN CENTRAL HIGHLANDS OF CHIAPAS, MEXICO

    Science.gov (United States)

    We present results of a study in an intensively impacted and highly fragmented landscape in which we apply field-measured carbon (C) density values to land-use/land-cover (LU/LC) statistics to estimate the flux of C between terrestrial ecosystems and the atmosphere from the 1970s...

  6. Soil organic carbon dynamics of improved fallow-maize rotation systems under conventional and no-tillage in Central Zimbabwe

    NARCIS (Netherlands)

    Nyamadzawo, G.; Chikowo, R.; Nyamugafata, P.; Nyamangara, J.; Giller, K.E.

    2008-01-01

    Fallowing increases soil organic carbon (SOC) during the fallowing phase. However, this benefit is lost quickly during the cropping phase. The objective of this study was to evaluate SOC dynamics of an improved fallow-maize rotation under no-tillage (NT) and conventional tillage (CT) from time of fa

  7. Effect of Secondary Cooling Conditions on Solidification Structure and Central Macrosegregation in Continuously Cast High-Carbon Rectangular Billet

    Science.gov (United States)

    Zeng, Jie; Chen, Weiqing

    2015-10-01

    Solidification structures of high carbon rectangular billet with a size of 180 mm × 240 mm in different secondary cooling conditions were simulated using cellular automaton-finite element (CAFE) coupling model. The adequacy of the model was compared with the simulated and the actual macrostructures of 82B steel. Effects of the secondary cooling water intensity on solidification structures including the equiaxed grain ratio and the equiaxed grain compactness were discussed. It was shown that the equiaxed grain ratio and the equiaxed grain compactness changed in the opposite direction at different secondary cooling water intensities. Increasing the secondary cooling water intensity from 0.9 or 1.1 to 1.3 L/kg could improve the equiaxed grain compactness and decrease the equiaxed grain ratio. Besides, the industrial test was conducted to investigate the effect of different secondary cooling water intensities on the center carbon macrosegregation of 82B steel. The optimum secondary cooling water intensity was 0.9 L/kg, while the center carbon segregation degree was 1.10. The relationship between solidification structure and center carbon segregation was discussed based on the simulation results and the industrial test.

  8. A new approach to understand methylmercury (CH3Hg) sources and transformation pathways: Compound-specific carbon stable isotope analysis by GC-C-IRMS

    Science.gov (United States)

    Baya, P. A.; Point, D.; Amouroux, D. P.; Lebreton, B.; Guillou, G.

    2015-12-01

    Methylmercury (CH3Hg) is a potent neurotoxin which is readily assimilated by organisms and bio-accumulates in aquatic food webs. In humans, consumption of CH3Hg contaminated marine fish is the major route of mercury exposure. However, our understanding of CH3Hg transformation pathways is still incomplete. To close this knowledge gap, we propose to explore the stable carbon isotopic composition (δ13C) of the methyl group of CH3Hg for a better understanding of its sources and transformation mechanisms. The method developed for the determination of the δ13C value of CH3Hg in biological samples involves (i) CH3Hg selective extraction, (ii) derivatization, and (iii) separation by gas chromatography (GC) prior to analysis by combustion isotope ratio mass spectrometry (C-IRMS). We present the figures of merit of this novel method and the first δ13C signatures for certified materials (ERM-CE464, BCR414) and biological samples at different marine trophic levels (i.e., tuna fish, zooplankton). The implications of this new approach to trace the pathways associated with Hg methylation and the mechanisms involved will be discussed.

  9. Carbon nanotube-based substrates promote cardiogenesis in brown adipose-derived stem cells via β1-integrin-dependent TGF-β1 signaling pathway

    Science.gov (United States)

    Sun, Hongyu; Mou, Yongchao; Li, Yi; Li, Xia; Chen, Zi; Duval, Kayla; Huang, Zhu; Dai, Ruiwu; Tang, Lijun; Tian, Fuzhou

    2016-01-01

    Stem cell-based therapy remains one of the promising approaches for cardiac repair and regeneration. However, its applications are restricted by the limited efficacy of cardiac differentiation. To address this issue, we examined whether carbon nanotubes (CNTs) would provide an instructive extracellular microenvironment to facilitate cardiogenesis in brown adipose-derived stem cells (BASCs) and to elucidate the underlying signaling pathways. In this study, we systematically investigated a series of cellular responses of BASCs due to the incorporation of CNTs into collagen (CNT-Col) substrates that promoted cell adhesion, spreading, and growth. Moreover, we found that CNT-Col substrates remarkably improved the efficiency of BASCs cardiogenesis by using fluorescence staining and quantitative real-time reverse transcription-polymerase chain reaction. Critically, CNTs in the substrates accelerated the maturation of BASCs-derived cardiomyocytes. Furthermore, the underlying mechanism for promotion of BASCs cardiac differentiation by CNTs was determined by immunostaining, quantitative real-time reverse transcription-polymerase chain reaction, and Western blotting assay. It is notable that β1-integrin-dependent TGF-β1 signaling pathway modulates the facilitative effect of CNTs in cardiac differentiation of BASCs. Therefore, it is an efficient approach to regulate cardiac differentiation of BASCs by the incorporation of CNTs into the native matrix. Importantly, our findings can not only facilitate the mechanistic understanding of molecular events initiating cardiac differentiation in stem cells, but also offer a potentially safer source for cardiac regenerative medicine. PMID:27660434

  10. Carbon ion beam triggers both caspase-dependent and caspase-independent pathway of apoptosis in HeLa and status of PARP-1 controls intensity of apoptosis.

    Science.gov (United States)

    Ghorai, Atanu; Sarma, Asitikantha; Bhattacharyya, Nitai P; Ghosh, Utpal

    2015-04-01

    High linear energy transfer (LET) carbon ion beam (CIB) is becoming very promising tool for various cancer treatments and is more efficient than conventional low LET gamma or X-rays to kill malignant or radio-resistant cells, although detailed mechanism of cell death is still unknown. Poly (ADP-ribose) polymerase-1 (PARP-1) is a key player in DNA repair and its inhibitors are well-known as radio-sensitizer for low LET radiation. The objective of our study was to find mechanism(s) of induction of apoptosis by CIB and role of PARP-1 in CIB-induced apoptosis. We observed overall higher apoptosis in PARP-1 knocked down HeLa cells (HsiI) compared with negative control H-vector cells after irradiation with CIB (0-4 Gy). CIB activated both intrinsic and extrinsic pathways of apoptosis via caspase-9 and caspase-8 activation respectively, followed by caspase-3 activation, apoptotic body, nucleosomal ladder formation and sub-G1 accumulation. Apoptosis inducing factor translocation into nucleus in H-vector but not in HsiI cells after CIB irradiation contributed caspase-independent apoptosis. Higher p53 expression was observed in HsiI cells compared with H-vector after exposure with CIB. Notably, we observed about 37 % fall of mitochondrial membrane potential, activation of caspase-9 and caspase-3 and mild activation of caspase-8 without any detectable apoptotic body formation in un-irradiated HsiI cells. We conclude that reduction of PARP-1 expression activates apoptotic signals via intrinsic and extrinsic pathways in un-irradiated cells. CIB irradiation further intensified both intrinsic and extrinsic pathways of apoptosis synergistically along with up-regulation of p53 in HsiI cells resulting overall higher apoptosis in HsiI than H-vector.

  11. Changes in ecosystem structure related to the type and extent of woody cover alter carbon dynamics and surface energy exchange in central Texas ecosystems.

    Science.gov (United States)

    Litvak, M. E.; Heilman, J.; McInnes, K.; Owens, K.; Kjelgaard, J.; Thijs, A.

    2006-12-01

    Rangeland ecosystems account for almost two thirds the total land area in Texas. Over the past century, heavy livestock grazing and fire suppression coupled with changes in climate have facilitated the expansion of woody species into rangelands throughout the state. Based in part on the assumption that woody species use more water than their herbaceous counterparts, land managers have used a variety of techniques to reduce tree and shrub abundance to combat the loss of forage for cattle. As a result, the structure of rangelands in Texas is complex, characterized by woody vegetation that is patchy in distribution, and continually changing between grassland, savanna and woodland. Despite the large areal extent of Texas rangelands, very little is known about how the observed changes in ecosystem structure impact carbon cycle dynamics and surface energy exchange. To reduce these uncertainties, we explored explicit relationships between structure and function in these ecosystems by comparing tower-based measurements of carbon and water vapor exchange made simultaneously from July 2004-Dec 2005 across three representative land covers in central Texas: open grassland, savanna with 30% Ashe juniper and honey mesquite cover, and closed canopy woodland. Here we report our findings on what impact the type and pattern of woody plant cover has on biological controls and patterns of carbon sequestration, evapotranspiration, and sensitivity to precipitation pulses. Monthly measurements of leaf level gas exchange, soil respiration rates, herbaceous net ecosystem exchange, and sap flow measurements on dominant woody species were used to augment eddy covariance estimates of ecosystem-atmosphere exchange. The addition of woody species significantly increased carbon sequestration in these ecosystems. Net ecosystem production from July 05-Jun 05 in the grassland, savanna and forest ecosystems was -14 g C m-2, -413 g C m-2, -450 g C m-2, respectively. Evapotranspiration was less

  12. Carbon balance at represenative agroecosystems of Central European Russia with different crops assessed by eddy covariance method

    Science.gov (United States)

    Yaroslavtsev, Alexis; Meshalkina, Joulia; Mazirov, Ilya

    2016-04-01

    Despite the fact that in Russia cropland's soils carbon loses 9 time higher than forest's soils ones (Stolbovoi, 2002), agroecosystems were not given sufficient attention and most of the papers are devoted to forestry and natural ecosystems. Carbon balance was calculated at the Precision Farming Experimental Fields of the Russian Timiryazev State Agricultural University, Moscow, Russia, for two agroecosystems with different crops from the same crop rotation studied for 2 years. The experimental site has a temperate and continental climate and situated in south taiga zone with Arable Sod-Podzoluvisols (Albeluvisols Umbric). Vertical fluxes of carbon dioxide were measured with eddy covariance technique, statistical method to measure and calculate turbulent fluxes within atmospheric boundary layers (Burba, 2013). Crop rotation included potato, winter wheat, barley and vetch and oat mix. Two fields of the same crop rotation were studied in 2013-2014. One of the fields (A) was used in 2013 for barley planting (Hordeum vulgare L.). The field B was in 2013 used for planting together vetch (Vicia sativa L.) and oats (Avena sativa L.). Inversely oats and vetch grass mixt was sown in 2014 on field A. Winter wheat was sown on field A in the very beginning of September. On the second field (B) in 2014 winter wheat occurred from under the snow in the phase of tillering, after harvesting it in mid of July, white mustard (Sinapis alba) was sown for green manure. Carbon uptake (NEE negative values) was registered only for the field with winter wheat and white mustard; perhaps because the two crops were cultivated on the field within one growing season. Three other cases showed CO2 emission. Great difference in 82 g C m‑2 per year in NEE between two fields with vetch and oat mix was related to higher difference in grass yields. NEE for barley field was positive during the whole year; considering only the growing season, NEE for barley was 100 g C m‑2 lower and was negative

  13. Carbon balance at represenative agroecosystems of Central European Russia with different crops assessed by eddy covariance method

    Science.gov (United States)

    Yaroslavtsev, Alexis; Meshalkina, Joulia; Mazirov, Ilya

    2016-04-01

    Despite the fact that in Russia cropland's soils carbon loses 9 time higher than forest's soils ones (Stolbovoi, 2002), agroecosystems were not given sufficient attention and most of the papers are devoted to forestry and natural ecosystems. Carbon balance was calculated at the Precision Farming Experimental Fields of the Russian Timiryazev State Agricultural University, Moscow, Russia, for two agroecosystems with different crops from the same crop rotation studied for 2 years. The experimental site has a temperate and continental climate and situated in south taiga zone with Arable Sod-Podzoluvisols (Albeluvisols Umbric). Vertical fluxes of carbon dioxide were measured with eddy covariance technique, statistical method to measure and calculate turbulent fluxes within atmospheric boundary layers (Burba, 2013). Crop rotation included potato, winter wheat, barley and vetch and oat mix. Two fields of the same crop rotation were studied in 2013-2014. One of the fields (A) was used in 2013 for barley planting (Hordeum vulgare L.). The field B was in 2013 used for planting together vetch (Vicia sativa L.) and oats (Avena sativa L.). Inversely oats and vetch grass mixt was sown in 2014 on field A. Winter wheat was sown on field A in the very beginning of September. On the second field (B) in 2014 winter wheat occurred from under the snow in the phase of tillering, after harvesting it in mid of July, white mustard (Sinapis alba) was sown for green manure. Carbon uptake (NEE negative values) was registered only for the field with winter wheat and white mustard; perhaps because the two crops were cultivated on the field within one growing season. Three other cases showed CO2 emission. Great difference in 82 g C m-2 per year in NEE between two fields with vetch and oat mix was related to higher difference in grass yields. NEE for barley field was positive during the whole year; considering only the growing season, NEE for barley was 100 g C m-2 lower and was negative. Closed

  14. The impact of land-cover change on carbon and water cycling in the U.S. central plains grasslands

    Science.gov (United States)

    Buck, Tyler

    Using the eddy covariance technique, the impact of land cover variability on carbon and water cycling was examined at three different grasslands in Northeast Kansas. One site 8 km north of Lawrence, Kansas at the Nelson Environmental Study Area (NESA) experiences woody-encroachment and is burned every three years. The remaining two sites are located at the Konza Prairie Biological Station, 8 km south of Manhattan, Kansas. KZU is located in an annual burned, non-grazed watershed in an upland area. K4B experiences woody encroachment and has prescribed burns every four years. Water-use efficiency was used to examine how the carbon and water cycling of these ecosystems respond to land cover change. Analysis suggest that the two grasslands experiencing woody-encroachment (NESA and K4B) show more efficient water use values than the grassland that is not (KZU). This may be due to a possible difference in rooting depth between woody-vegetation and grasses.

  15. Multi-frequency observations of seawater carbonate chemistry on the central coast of the western Antarctic Peninsula

    Directory of Open Access Journals (Sweden)

    Julie B. Schram

    2015-07-01

    Full Text Available Assessments of benthic coastal seawater carbonate chemistry in Antarctica are sparse. The studies have generally been short in duration, during the austral spring/summer, under sea ice, or offshore in ice-free water. Herein we present multi-frequency measurements for seawater collected from the shallow coastal benthos on a weekly schedule over one year (May 2012–May 2013, daily schedule over three months (March–May 2013 and semidiurnal schedule over five weeks (March–April 2013. A notable pH increase (max pH = 8.62 occurred in the late austral spring/summer (November–December 2012, coinciding with sea-ice break-out and subsequent increase in primary productivity. We detected semidiurnal variation in seawater pH with a maximum variation of 0.13 pH units during the day and 0.11 pH units during the night. Daily variation in pH is likely related to biological activity, consistent with previous research. We calculated the variation in dissolved inorganic carbon (DIC over each seawater measurement frequency, focusing on the primary DIC drivers in the Palmer Station region. From this, we estimated net biological activity and found it accounts for the greatest variations in DIC. Our seasonal data suggest that this coastal region tends to act as a carbon dioxide source during austral winter months and as a strong sink during the summer. These data characterize present-day seawater carbonate chemistry and the extent to which these measures vary over multiple time scales. This information will inform future experiments designed to evaluate the vulnerability of coastal benthic Antarctic marine organisms to ocean acidification.

  16. Impact of Soil Conservation Policies on Carbon Sequestration in Agricultural Soils of the Central United States (The)

    OpenAIRE

    Mitchell, Paul D.; P. G. Lakshminarayan; Toshitsugu Otake; Babcock, Bruce A.

    1996-01-01

    To evaluate the impact of conservation policies on soil organic carbon in agricultural soils, the authors link information from the 1992 National Resources Inventory (NRI) database and the extensive physical data on soils and climate from the SOILS5 database. These data serve as input for a biophysical process model calibrated for the conditions prevalent in the study region. Results indicate that reducing soil erosion, rather than removing land from agricultural production, is the most effec...

  17. Recovery of Carbonate Ecosystems Following the End-Triassic Mass Extinction: Insights from Mercury Anomalies and Their Relationship to the Central Atlantic Magmatic Province

    Science.gov (United States)

    Corsetti, F. A.; Thibodeau, A. M.; Ritterbush, K. A.; West, A. J.; Yager, J. A.; Ibarra, Y.; Bottjer, D. J.; Berelson, W.; Bergquist, B. A.

    2015-12-01

    Recent high-resolution age dating demonstrates that the end-Triassic mass extinction overlapped with the eruption of the Central Atlantic Magmatic Province (CAMP), and the release of CO2 and other volatiles to the atmosphere has been implicated in the extinction. Given the potentially massive release of CO2, ocean acidification is commonly considered a factor in the extinction and the collapse of shallow marine carbonate ecosystems. However, the timing of global marine biotic recovery versus the CAMP eruptions is more uncertain. Here, we use Hg concentrations and Hg/TOC ratios as indicators of CAMP volcanism in continental shelf sediments, the primary archive of faunal data. In Triassic-Jurassic strata, Muller Canyon, Nevada, Hg and Hg/TOC levels are low prior to the extinction, rise sharply in the extinction interval, peak just prior to the appearance of the first Jurassic ammonite, and remain above background in association with a depauperate (low diversity) earliest Jurassic fauna. The return of Hg to pre-extinction levels is associated with a significant pelagic and benthic faunal recovery. We conclude that significant biotic recovery did not begin until CAMP eruptions ceased. Furthermore, the initial benthic recovery in the Muller Canyon section involves the expansion of a siliceous sponge-dominated ecosystem across shallow marine environments, a feature now known from other sections around the world (e.g., Peru, Morocco, Austria, etc.). Carbonate dominated benthic ecosystems (heralded by the return of abundant corals and other skeletal carbonates) did not recover for ~1 million years following the last eruption of CAMP, longer than the typical duration considered for ocean acidification events, implying other factors may have played a role in carbonate ecosystem dynamics after the extinction.

  18. Comparison of coniferous forest carbon stocks between old-growth and young second-growth forests on two soil types in central British Columbia, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Fredeen, A.L.; Bois, C.H.; Janzen, D.T.; Sanborn, P.T. [Northern British Columbia Univ., Prince George, BC (Canada). Faculty of Natural Resources and Environmental Studies

    2005-06-01

    More than half of the world's terrestrial organic soil and vegetation carbon (C) currently resides in forests, with one half of this in boreal forests alone. Forests therefore represent significant reservoirs of carbon. A study was conducted at the Aleza Lake Research Forest (ALRF) near Prince George, British Columbia to compare the C stocks in 4 old-growth sub-boreal spruce (SBS) forests with 4 corresponding young, planted second-growth stands in soils of contrasting textures. The 2 dominant soil textures were coarse and fine grained soils over a total of 16 plots. The C stocks were assessed for hybrid interior spruce-dominated upland forests within the ALRF. For each plot, the carbon content of tree biomass was estimated using the measured values of Lamlom and Savidge. All woody debris stocks including tree stumps were also evaluated and soil C stocks were sampled according to modified National Forest Inventory Sampling Guidelines. C stocks were also tested for mineral soil texture, age-class and their interaction effects. The average total C stocks for old-growth stands ranged from 423 Mg C per hectare to 324 Mg C per hectare, between Pacific Northwest temperate forest and upland boreal forests. It was concluded that sub-boreal forests of central British Columbia are intermediate in terms of aboveground and total carbon stocks between the wetter and more productive coastal forests to the south and west and the less productive boreal stands to the north and east. It was concluded that conservation of non-biomass C stocks in old-growth forests is important in minimizing greenhouse gas emissions resulting from sub-boreal forest management activities. 60 refs., 2 tabs., 4 figs.

  19. Contrasting total carbon and nitrogen stocks between ecological site types in a Sub-Boreal research forest in central British Columbia

    Energy Technology Data Exchange (ETDEWEB)

    Bois, C.H.; Janzen, D.T. [Northern British Columbia Univ., Prince George, BC (Canada). Ecosystem Science and Management Program; Sanborn, P.T.; Fredeen, A.L. [Northern British Columbia Univ., Prince George, BC (Canada). Ecosystem Science and Management Program]|[Northern British Columbia Univ., Prince George, BC (Canada). Natural Resources and Environmental Studies Inst.

    2006-07-01

    Carbon (C) sequestration and carbon stocks within managed and natural forests have become topical issues since the adoption of the Kyoto Protocol. A multi-year study was conducted to evaluate the total C stocks present in a 10 km{sup 2} area of University of British Columbia's Aleza Lake Research Forest located 60 km east of Prince George in the Sub-Boreal Spruce biogeoclimatic zone of east-central British Columbia. The purpose was to address gaps in knowledge about forest C budgets, total pool sizes, dynamics of forest floor and mineral soil carbon by studying the effects of forest management. Sampling plots were chosen randomly within strata composed of the dominant ecological site classes, soil textures and management histories. The study involved the creation of 137 plots, of which 108 and 29 were located on fine and coarse textured soils, respectively. Sampling was reduced in these strata due to a shortage of middle-aged stands and the near lack of coarse textured soils. Data collection and sampling methodology were adapted from the National Forest Inventory Ground Sampling Guidelines of the Canadian Forest Service. Carbon stocks were measured in forest floor and mineral soil to a depth of 1 metre. The Dumas-combustion method was used to determine C and nitrogen (N) concentrations. It was determined that stand age did not decidedly change the forest floor or mineral soil total C and N in either fine or coarse textured soil plots. However, forest floor C and N were considerably higher in coarse textured soils compared to C and N measured in fine soil plots. Mineral soil C concentration decreased methodically with depth from 4.6 per cent C at 0 cm to 0.2 per cent at 100 cm. The paper also addressed the breakdown of forest floor and mineral soil C and N pools according to ecological site series.

  20. Use of dual carbon-chlorine isotope analysis to assess the degradation pathways of 1,1,1-trichloroethane in groundwater.

    Science.gov (United States)

    Palau, Jordi; Jamin, Pierre; Badin, Alice; Vanhecke, Nicolas; Haerens, Bruno; Brouyère, Serge; Hunkeler, Daniel

    2016-04-01

    Compound-specific isotope analysis (CSIA) is a powerful tool to track contaminant fate in groundwater. However, the application of CSIA to chlorinated ethanes has received little attention so far. These compounds are toxic and prevalent groundwater contaminants of environmental concern. The high susceptibility of chlorinated ethanes like 1,1,1-trichloroethane (1,1,1-TCA) to be transformed via different competing pathways (biotic and abiotic) complicates the assessment of their fate in the subsurface. In this study, the use of a dual C-Cl isotope approach to identify the active degradation pathways of 1,1,1-TCA is evaluated for the first time in an aerobic aquifer impacted by 1,1,1-TCA and trichloroethylene (TCE) with concentrations of up to 20 mg/L and 3.4 mg/L, respectively. The reaction-specific dual carbon-chlorine (C-Cl) isotope trends determined in a recent laboratory study illustrated the potential of a dual isotope approach to identify contaminant degradation pathways of 1,1,1-TCA. Compared to the dual isotope slopes (Δδ(13)C/Δδ(37)Cl) previously determined in the laboratory for dehydrohalogenation/hydrolysis (DH/HY, 0.33 ± 0.04) and oxidation by persulfate (∞), the slope determined from field samples (0.6 ± 0.2, r(2) = 0.75) is closer to the one observed for DH/HY, pointing to DH/HY as the predominant degradation pathway of 1,1,1-TCA in the aquifer. The observed deviation could be explained by a minor contribution of additional degradation processes. This result, along with the little degradation of TCE determined from isotope measurements, confirmed that 1,1,1-TCA is the main source of the 1,1-dichlorethylene (1,1-DCE) detected in the aquifer with concentrations of up to 10 mg/L. This study demonstrates that a dual C-Cl isotope approach can strongly improve the qualitative and quantitative assessment of 1,1,1-TCA degradation processes in the field. PMID:26874254

  1. Patterns of soil carbon and nitrogen in relation to soil movement under different land uses in mountain farmland fields (South Central Pyrenees)

    Science.gov (United States)

    Navas, A.; Gaspar, L.; López-Vicente, M.; Machín, J.

    2009-04-01

    Cultivation on mountain landscapes has been identified as a main factor triggering soil erosion. The loss of soil particles and its redistribution across the landscape is associated to that of soil nutrients. Patterns of soil erosion and of the transport and redistribution of soil particles appear to be closely linked to that of carbon in soils. In this work the redistribution of total organic carbon and nitrogen and that of soil particles is analysed in different geomorphic parts of mountain farmland fields. A southern orientated hillslope in the Central Spanish Pyrenees was selected as representative of main land uses. In the region, farmland abandonment during the last decades affects 74 % of its surface and therefore patterns of soil and nutrient losses in the fields are affected by land abandonments and tillage. A set of cultivated and abandoned fields with different ages of land abandonment, slope gradients and length were selected to conduct this study. In each of the fields, sampling was carried out in different parts of the slope to assess the pattern of particle size distribution and of total organic carbon (TOC) and total nitrogen (TN). Other general soil properties analysed: pH, EC and carbonate contents provided supplementary information for better understanding soil and nutrient redistribution patterns. In addition, information provided by a previous research using fallout caesium 137 was used to document soil movement in these fields. At the bottom slope of the fields significant increases in the sand percentage occurs whereas the clay contents decrease slightly. This could be due to the export of the finest fractions with high runoff in spite that fields are surrounded with stone walls as well as to some clay leaching in the soil profile, as suggested by the lowest values of EC at the bottom of the slope. The results indicate that in general TOC increases from the crest to the bottom slope of the fields. Percentages of TOC increases range from 5 to

  2. Internalization of externalities in the generation costs of electric power centrals of carbon, combined cycle and nuclear; Internalizacion de externalidades en los costos de generacion de centrales electricas de carbon, ciclo combinado y nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Gomez R, M.C. [Universidad Anahuac del Norte (Mexico); Palacios H, J.; Ramirez S, R.; Alonso V, G. [ININ, Carretera Mexico-Toluca Km. 36.5 Ocoyoacac 52750 Edo. de Mexico (Mexico)]. e-mail: fgrivera@avantel.net

    2007-07-01

    The technologies of electric power generation that use fossil fuels, they incorporate in the Even Total Cost of Generation (CTNG) only the direct costs of generation (investment, fuel costs, operation costs and maintenance). nevertheless, the nuclear energy incorporates besides the direct costs, the externalities that causes to the human health and the environment. In this work the CTNG is calculated that incorporates the externalities, of a thermoelectric power station of coal, a plant of combined cycle and of four reactors of Generation III (ABWR, ACR, AP1000 and EPR). The obtained results show that the nuclear power station has smaller CTNG that the technologies that use fossil fuels. It is important to stand out that they are only considering the externalities of the stage of electricity generation, for what the mining phase and transport of the fuel toward the central are not considered in the present document. (Author)

  3. Genes and pathways for CO2 fixation in the obligate, chemolithoautotrophic acidophile, Acidithiobacillus ferrooxidans, Carbon fixation in A. ferrooxidans

    Directory of Open Access Journals (Sweden)

    Esparza Mario

    2010-08-01

    Full Text Available Abstract Background Acidithiobacillus ferrooxidans is chemolithoautotrophic γ-proteobacterium that thrives at extremely low pH (pH 1-2. Although a substantial amount of information is available regarding CO2 uptake and fixation in a variety of facultative autotrophs, less is known about the processes in obligate autotrophs, especially those living in extremely acidic conditions, prompting the present study. Results Four gene clusters (termed cbb1-4 in the A. ferrooxidans genome are predicted to encode enzymes and structural proteins involved in carbon assimilation via the Calvin-Benson-Bassham (CBB cycle including form I of ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO, EC 4.1.1.39 and the CO2-concentrating carboxysomes. RT-PCR experiments demonstrated that each gene cluster is a single transcriptional unit and thus is an operon. Operon cbb1 is divergently transcribed from a gene, cbbR, encoding the LysR-type transcriptional regulator CbbR that has been shown in many organisms to regulate the expression of RubisCO genes. Sigma70-like -10 and -35 promoter boxes and potential CbbR-binding sites (T-N11-A/TNA-N7TNA were predicted in the upstream regions of the four operons. Electrophoretic mobility shift assays (EMSAs confirmed that purified CbbR is able to bind to the upstream regions of the cbb1, cbb2 and cbb3 operons, demonstrating that the predicted CbbR-binding sites are functional in vitro. However, CbbR failed to bind the upstream region of the cbb4 operon that contains cbbP, encoding phosphoribulokinase (EC 2.7.1.19. Thus, other factors not present in the assay may be required for binding or the region lacks a functional CbbR-binding site. The cbb3 operon contains genes predicted to encode anthranilate synthase components I and II, catalyzing the formation of anthranilate and pyruvate from chorismate. This suggests a novel regulatory connection between CO2 fixation and tryptophan biosynthesis. The presence of a form II Rubis

  4. Phosphoketolase pathway dominates in Lactobacillus reuteri ATCC 55730 containing dual pathways for glycolysis.

    Science.gov (United States)

    Arsköld, Emma; Lohmeier-Vogel, Elke; Cao, Rong; Roos, Stefan; Rådström, Peter; van Niel, Ed W J

    2008-01-01

    Metabolic flux analysis indicated that the heterofermentative Lactobacillus reuteri strain ATCC 55730 uses both the Embden-Meyerhof pathway (EMP) and phosphoketolase pathway (PKP) when glucose or sucrose is converted into the three-carbon intermediate stage of glycolysis. In all cases studied, the main flux is through the PKP, while the EMP is used as a shunt. In the exponential growth phase, 70%, 73%, and 84% of the flux goes through the PKP in cells metabolizing (i) glucose plus fructose, (ii) glucose alone, and (iii) sucrose alone, respectively. Analysis of the genome of L. reuteri ATCC 55730 confirmed the presence of the genes for both pathways. Further evidence for the simultaneous operation of two central carbon metabolic pathways was found through the detection of fructose-1,6-bisphosphate aldolase, phosphofructokinase, and phosphoglucoisomerase activities and the presence of phosphorylated EMP and PKP intermediates using in vitro 31P NMR. The maximum specific growth rate and biomass yield obtained on glucose were twice as low as on sucrose. This was the result of low ATP levels being present in glucose-metabolizing cells, although the ATP production flux was as high as in sucrose-metabolizing cells due to a twofold increase of enzyme activities in both glycolytic pathways. Growth performance on glucose could be improved by adding fructose as an external electron acceptor, suggesting that the observed behavior is due to a redox imbalance causing energy starvation. PMID:17965151

  5. Coprecipitation of (14)C and Sr with carbonate precipitates: The importance of reaction kinetics and recrystallization pathways.

    Science.gov (United States)

    Hodkin, David J; Stewart, Douglas I; Graham, James T; Burke, Ian T

    2016-08-15

    This study investigated the simultaneous removal of Sr(2+) and (14)CO3(2-) from pH>12 Ca(OH)2 solution by the precipitation of calcium carbonate. Initial Ca(2+):CO3(2-) ratios ranged from 10:1 to 10:100 (mM:mM). Maximum removal of (14)C and Sr(2+) both occurred in the system containing 10mM Ca(2+) and 1mM CO3(2-) (99.7% and 98.6% removal respectively). A kinetic model is provided that describes (14)C and Sr removal in terms of mineral dissolution and precipitation reactions. The removal of (14)C was achieved during the depletion of the initial TIC in solution, and was subsequently significantly affected by recrystallization of the calcite precipitate from an elongate to isotropic morphology. This liberated >46% of the (14)C back to solution. Sr(2+) removal occurred as Ca(2+) became depleted in solution and was not significantly affected by the recrystallization process. The proposed reaction could form the basis for low cost remediation scheme for (90)Sr and (14)C in radioactively contaminated waters (<$0.25 reagent cost per m(3) treated).

  6. Central composite design and genetic algorithm applied for the optimization of ultrasonic-assisted removal of malachite green by ZnO Nanorod-loaded activated carbon.

    Science.gov (United States)

    Ghaedi, M; Azad, F Nasiri; Dashtian, K; Hajati, S; Goudarzi, A; Soylak, M

    2016-10-01

    Maximum malachite green (MG) adsorption onto ZnO Nanorod-loaded activated carbon (ZnO-NR-AC) was achieved following the optimization of conditions, while the mass transfer was accelerated by ultrasonic. The central composite design (CCD) and genetic algorithm (GA) were used to estimate the effect of individual variables and their mutual interactions on the MG adsorption as response and to optimize the adsorption process. The ZnO-NR-AC surface morphology and its properties were identified via FESEM, XRD and FTIR. The adsorption equilibrium isotherm and kinetic models investigation revealed the well fit of the experimental data to Langmuir isotherm and pseudo-second-order kinetic model, respectively. It was shown that a small amount of ZnO-NR-AC (with adsorption capacity of 20mgg(-1)) is sufficient for the rapid removal of high amount of MG dye in short time (3.99min). PMID:27318150

  7. Central composite design and genetic algorithm applied for the optimization of ultrasonic-assisted removal of malachite green by ZnO Nanorod-loaded activated carbon

    Science.gov (United States)

    Ghaedi, M.; Azad, F. Nasiri; Dashtian, K.; Hajati, S.; Goudarzi, A.; Soylak, M.

    2016-10-01

    Maximum malachite green (MG) adsorption onto ZnO Nanorod-loaded activated carbon (ZnO-NR-AC) was achieved following the optimization of conditions, while the mass transfer was accelerated by ultrasonic. The central composite design (CCD) and genetic algorithm (GA) were used to estimate the effect of individual variables and their mutual interactions on the MG adsorption as response and to optimize the adsorption process. The ZnO-NR-AC surface morphology and its properties were identified via FESEM, XRD and FTIR. The adsorption equilibrium isotherm and kinetic models investigation revealed the well fit of the experimental data to Langmuir isotherm and pseudo-second-order kinetic model, respectively. It was shown that a small amount of ZnO-NR-AC (with adsorption capacity of 20 mg g- 1) is sufficient for the rapid removal of high amount of MG dye in short time (3.99 min).

  8. Influences of riverine and upwelling waters on the coastal carbonate system off Central Chile and their ocean acidification implications

    Science.gov (United States)

    Vargas, Cristian A.; Contreras, Paulina Y.; Pérez, Claudia A.; Sobarzo, Marcus; Saldías, Gonzalo S.; Salisbury, Joe

    2016-06-01

    A combined data set, combining data from field campaigns and oceanographic cruises, was used to ascertain the influence of both river discharges and upwelling processes, covering spatial and temporal variation in dissolved inorganic carbon (DIC) and aragonite saturation state. This work was conducted in one of the most productive river-influenced upwelling areas in the South Pacific coasts (36°S). Additionally, further work was also conducted to ascertain the contribution of different DIC sources, influencing the dynamics of DIC along the land-ocean range. Six sampling campaigns were conducted across seven stations at the Biobío River basin, covering approximately 200 km. Three research cruises were undertaken simultaneously, covering the adjacent continental shelf, including 12 sampling stations for hydrographic measurements. Additionally, six stations were also sampled for chemical analyses, covering summer, winter, and spring conditions over 2010 and 2011. Our results evidenced that seaward extent of the river plume was more evident during the winter field campaign, when highest riverine DIC fluxes were observed. The carbonate system along the river-ocean continuum was very heterogeneous varying over spatial and temporal scales. High DIC and pCO2 were observed in river areas with larger anthropogenic effects. CO2 supersaturation at the river plume was observed during all campaigns due to the influence of low pH river waters in winter/spring and high-pCO2 upwelling waters in summer. δ13CDIC evidenced that main DIC sources along the river and river plume corresponded to the respiration of terrestrial organic matter. We have linked this natural process to the carbonate saturation on the adjacent river-influenced coastal area, suggesting that Ωaragonite undersaturation in surface/subsurface waters is largely modulated by the influence of both river discharge and coastal upwelling events in this productive coastal area. Conditions of low Ωaragonite might impact

  9. Carbonate Sequence Stratigraphy of a Back-Arc Basin: A Case Study of the Qom Formation in the Kashan Area, Central Iran

    Institute of Scientific and Technical Information of China (English)

    XU Guoqiang; ZHANG Shaonan; LI Zhongdong; SONG Lailiang; LIU Huimin

    2007-01-01

    The Qom Formation comprises Oligo-Miocene deposits from a marine succession distributed in the Central Basin of Iran. It is composed of five members designated as A-F. Little previous work exists on the sequence stratigraphy. Based on an integrated study of sequence stratigraphy with outcrop data, wells and regional seismic profiles, the Qom Formation is interpreted as a carbonate succession deposited in a mid-Tertiary back-arc basin. There are two second-order sequences (designated as SS1 and SS2) and five third-order sequences (designated as S1-S5). Five distinct systems tracts including transgressive, highstand, forced regressive, slope margin and lowstand have been recognized. The relationship between the sequences and lithologic sub-units has been collated and defined (S1 to S5 individually corresponding to A-C1, C2-C4, D-E, the lower and upper portions of F); a relative sea level change curve and the sequence stratigraphic framework have been established and described in detail. The coincidence of relative sea level change between that of the determined back-arc basin and the world indicates that the sedimentary cycles of the Qom Formation are mainly controlled by eustatic cycles. The variable combination of the systems tracts and special tectonic-depositional setting causally underpin multiple sequence stratigraphic framework styles seen in the carbonates of the back-arc basin revealing: (1) a continental margin basin that developed some form of barrier, characterized by the development of multiple cycles of carbonate-evaporites; (2) a flat carbonate ramp, which occurred on the southern shelf formed by the lack of clastic supply from nearby magmatic islands plus mixed siliciclastics and carbonates that occurred on the northern shelf due to a sufficient clastics supply from the land; and (3) a forced regressive stratigraphic stacking pattern that occured on the southern shelf and in basin lows due to the uplifting of the southern shelf. Thick and widespread

  10. Carbon cycle dynamics and solar activity embedded in a high-resolution 14C speleothem record from Belize, Central America

    Science.gov (United States)

    Lechleitner, Franziska A.; Breitenbach, Sebastian F. M.; McIntyre, Cameron; Asmerom, Yemane; Prufer, Keith M.; Polyak, Victor; Culleton, Brendan J.; Kennett, Douglas J.; Eglinton, Timothy I.; Baldini, James U. L.

    2015-04-01

    Speleothem 14C has recently emerged as a potentially powerful proxy for climate reconstruction. Several studies have highlighted the link between karst hydrology and speleothem 14C content, and a number of possible causes for this relationship have been proposed, such as dripwater flow dynamics in the karst and changes in soil organic matter (SOM) turnover time (e.g. Griffiths et al., 2012). Here we present a high resolution 14C record for a stalagmite (YOK-I) from Yok Balum cave in southern Belize, Central America. YOK-I grew continuously over the last 2000 years, and has been dated very precisely with the U-Th method (40 dates, mean uncertainty ventilation and hydrologic resilience to seismic activity, Journal of Cave and Karst Studies

  11. Effects of tillage and nitrogen fertilizers on CH4 and CO2 emissions and soil organic carbon in paddy fields of central China.

    Directory of Open Access Journals (Sweden)

    Li Cheng-Fang

    Full Text Available Quantifying carbon (C sequestration in paddy soils is necessary to help better understand the effect of agricultural practices on the C cycle. The objective of the present study was to assess the effects of tillage practices [conventional tillage (CT and no-tillage (NT] and the application of nitrogen (N fertilizer (0 and 210 kg N ha(-1 on fluxes of CH(4 and CO(2, and soil organic C (SOC sequestration during the 2009 and 2010 rice growing seasons in central China. Application of N fertilizer significantly increased CH(4 emissions by 13%-66% and SOC by 21%-94% irrespective of soil sampling depths, but had no effect on CO(2 emissions in either year. Tillage significantly affected CH(4 and CO(2 emissions, where NT significantly decreased CH(4 emissions by 10%-36% but increased CO(2 emissions by 22%-40% in both years. The effects of tillage on the SOC varied with the depth of soil sampling. NT significantly increased the SOC by 7%-48% in the 0-5 cm layer compared with CT. However, there was no significant difference in the SOC between NT and CT across the entire 0-20 cm layer. Hence, our results suggest that the potential of SOC sequestration in NT paddy fields may be overestimated in central China if only surface soil samples are considered.

  12. Effects of wind farm construction on concentrations and fluxes of dissolved organic carbon and suspended sediment from peat catchments at Braes of Doune, central Scotland

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    I. Grieve

    2008-07-01

    Full Text Available This paper assesses the impacts of disturbance associated with the construction of a wind farm on fluxes of dissolved organic carbon (DOC and suspended sediment from a blanket peat catchment in central Scotland during the period immediately following completion of construction. Six streams draining the site were sampled on six dates from October 2006, when construction was completed, and an additional three control streams to the west of the site were sampled on the same dates. Turbidity and stage were recorded semi-continuously in the two largest streams (one disturbed and one control, which were also sampled during storm events. Absorbance (400 nm and DOC concentrations were determined on all samples, and suspended sediment was determined on the event samples. Absorbance and DOC were closely correlated in both the disturbed and undisturbed streams, with slightly greater absorbance per unit DOC in the disturbed streams. DOC concentrations in disturbed tributaries were always greater than those in undisturbed streams, with mean differences ranging from 2 to around 5 mg L-1. DOC and stage were positively correlated during events with maximum concentrations in excess of 30 mg L 1 at peak flow. Suspended sediment concentrations were markedly elevated in the disturbed stream with maximum concentrations at peak flow some 4–5 times greater than in the control. The colour of the sediment suggested that it was highly organic in nature at peak flow, and suspended particulate organic carbon represented a further loss of C from the site. Using flow-weighted mean DOC concentrations calculated for the storms monitored in autumn 2007, dissolved carbon losses can be estimated for the catchments of the disturbed and control streams. From these data the additional DOC loss related to disturbance associated with the wind farm is estimated at 5 g m-2.

  13. Rhizobium leguminosarum bv. viciae 3841 Adapts to 2,4-Dichlorophenoxyacetic Acid with "Auxin-Like" Morphological Changes, Cell Envelope Remodeling and Upregulation of Central Metabolic Pathways.

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    Supriya V Bhat

    Full Text Available There is a growing need to characterize the effects of environmental stressors at the molecular level on model organisms with the ever increasing number and variety of anthropogenic chemical pollutants. The herbicide 2,4-dichlorophenoxyacetic acid (2,4-D, as one of the most widely applied pesticides in the world, is one such example. This herbicide is known to have non-targeted undesirable effects on humans, animals and soil microbes, but specific molecular targets at sublethal levels are unknown. In this study, we have used Rhizobium leguminosarum bv. viciae 3841 (Rlv as a nitrogen fixing, beneficial model soil organism to characterize the effects of 2,4-D. Using metabolomics and advanced microscopy we determined specific target pathways in the Rlv metabolic network and consequent changes to its phenotype, surface ultrastructure, and physical properties during sublethal 2,4-D exposure. Auxin and 2,4-D, its structural analogue, showed common morphological changes in vitro which were similar to bacteroids isolated from plant nodules, implying that these changes are related to bacteroid differentiation required for nitrogen fixation. Rlv showed remarkable adaptation capabilities in response to the herbicide, with changes to integral pathways of cellular metabolism and the potential to assimilate 2,4-D with consequent changes to its physical and structural properties. This study identifies biomarkers of 2,4-D in Rlv and offers valuable insights into the mode-of-action of 2,4-D in soil bacteria.

  14. Interaction between ultrapotassic magmas and carbonate rocks: Evidence from geochemical and isotopic (Sr, Nd, O) compositions of granular lithic clasts from the Alban Hills Volcano, Central Italy

    Science.gov (United States)

    Peccerillo, Angelo; Federico, Marcella; Barbieri, Mario; Brilli, Mauro; Wu, Tsai-Wan

    2010-05-01

    Magma-carbonate rock interaction is investigated through a geochemical and Sr-Nd-O isotope study of granular lithic clasts ( ejecta) from the Alban Hills ultrapotassic volcano, Central Italy. Some samples (Group-1) basically represent intrusive equivalents of Alban Hills magmas. A few samples (Group-2) are ultramafic, have high MgO (˜30 to 40 wt%) and δ 18O‰, and originated by accumulation of mafic phases that crystallised from ultrapotassic melts during assimilation of dolomitic rocks. Group-3 ejecta consist of dominant K-feldspar, and show major element compositions similar to phonolites, which, however, are absent among the Alban Hills volcanics. Finally, another group (Group-4) contains corroded K-feldspars, surrounded by a microgranular to porphyritic matrix, made of igneous minerals (K-feldspar, foids, clinopyroxene, phlogopite) plus wollastonite, garnet, and some cuspidine. Group-4 ejecta are depleted in SiO 2 and enriched in CaO with respect to Group-3. The analysed ejecta have similar 143Nd/ 144Nd (0.51204-0.51217) as the Alban Hills lavas, whereas 87Sr/ 86Sr (0.70900-0.71067) is similar to lower. Whole rocks δ 18O‰ ranges from +7.0 to +13.2, reaching maximum values in ultramafic samples. A positive correlation with CaO is observed in single rock groups. Large Ion Lithophile Element (LILE) abundances and REE fractionation are generally high, and extreme values of Th, U and LREE are found in some Group-3 and Group-4 rocks. Mineralogical, petrological and geochemical data reveal extensive interaction between magma and carbonate wall rocks, involving both dolostones and limestones. These processes had dramatic effects on magma compositions, especially on phonolites, which were transformed to foidites. Evidence of such a process is found in Group-4 samples, in which K-feldspar is observed to react with a matrix that represents strongly undersaturated melts formed by interaction between silicate magma and carbonates. Trace element data also testify to a

  15. Emergence and transmission pathways of rapidly evolving evolutionary branch C4a strains of human enterovirus 71 in the Central Plain of China.

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    Yong Zhang

    Full Text Available BACKGROUND: Large-scale outbreaks of hand, foot, and mouth disease (HFMD occurred repeatedly in the Central Plain of China (Shandong, Anhui, and Henan provinces from 2007 until now. These epidemics have increased in size and severity each year and are a major public health concern in mainland China. PRINCIPAL FINDINGS: Phylogenetic analysis was performed and a Bayesian Markov chain Monte Carlo tree was constructed based on the complete VP1 sequences of HEV71 isolates. These analyses showed that the HFMD epidemic in the Central Plain of China was caused by at least 5 chains of HEV71 transmission and that the virus continued to circulate and evolve over the winter seasons between outbreaks. Between 1998 and 2010, there were 2 stages of HEV71 circulation in mainland China, with a shift from evolutionary branch C4b to C4a in 2003-2004. The evolution rate of C4a HEV71 was 4.99×10(-3 substitutions per site per year, faster than the mean of all HEV71 genotypes. The most recent common ancestor estimates for the Chinese clusters dated to October 1994 and November 1993 for the C4a and C4b evolutionary branches, respectively. Compared with all C4a HEV71 strains, a nucleotide substitution in all C4b HEV71 genome (A to C reversion at nt2503 in the VP1 coding region, which caused amino acid substitution of VP1-10: Gln to His had reverted. CONCLUSIONS: The data suggest that C4a HEV71 strains introduced into the Central Plain of China are responsible for the recent outbreaks. The relationships among HEV71 isolates determined from the combined sequence and epidemiological data reveal the underlying seasonal dynamics of HEV71 circulation. At least 5 HEV71 lineages circulated in the Central Plain of China from 2007 to 2009, and the Shandong and Anhui lineages were found to have passed through a genetic bottleneck during the low-transmission winter season.

  16. Surface circulation patterns and the pathways of sea surface carbon dioxide (CO2 off northern Chile (~27.5° S between 30 and 10 kyr BP: global and/or local forcing?

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    R. Torres

    2010-03-01

    Full Text Available We present a reconstruction of past changes in partial pressure of CO2 (pCO2 from northern Chile (~27° S, between 10 and 30 kyr BP, based on carbon isotope composition of C37:2-alkenone. The high-pCO2 during the entire time series indicates that northern Chile upwelling system has been a permanent source of CO2 to the atmosphere. The multiproxy reconstruction suggests that the CO2 outgassing and sequestration pathways were modulated by local and global mechanisms. During global glacial conditions, an enhanced coastal upwelling forcing resulted in high-availability of deep water macronutrients and a CO2-supersaturated water column, which combined with high-inputs of iron from the continent, intensified the carbon sequestration pathway of the biological pump, through diatom biomass export. During the deglacial, a decrease in the upwelling forcing, an increment in water column stability and reduced continental inputs of iron are consistent with a larger role of calcifying organisms in the plankton assemblage in terms of carbon sequestration pathway through the carbonate system.

  17. High resolution leaf wax carbon and hydrogen isotopic record of late Holocene paleoclimate in arid Central Asia

    Directory of Open Access Journals (Sweden)

    B. Aichner

    2014-11-01

    precipitation (including snow-melt and thus leaf wax δ D values must also respond to shifts in the proportion of moisture derived from westerly storms during late winter/early spring. Downcore results give evidence for a gradual shift to cooler and wetter climates between 3.5 and 2.5 cal kyr BP, interrupted by a warm/dry episode between 3.0–2.7 kyr BP. Further cool and wet episodes occur between 1.9–1.5 kyr BP and between 0.6–0.1 kyr BP, the latter coeval with the Little Ice Age. Warm and dry episodes between 2.5–1.9 kyr BP and 1.5–0.6 kyr BP coincide with the Roman Warm Period and Medieval Climate Anomaly, respectively. Finally, we find a drying tend in recent decades. Regional comparisons lead us to infer that the strength and position of the Westerlies, and wider Northern Hemispheric climate dynamics control climatic shifts in arid Central Asia.

  18. The Effects of Detritus Input on Soil Organic Matter Content and Carbon Dioxide Emission in a Central European Deciduous Forest

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    FEKETE, István

    2011-01-01

    Full Text Available A major objective of our research was to survey soil biological activity and organic mattercontent reduction in a Central European oak forest during treatments of various detritus inputs within theSíkfkút DIRT (Detritus Input and Removal Treatments Project. Beside the control, three detritusremoval and two detritus duplication treatments were applied. Our examinations have proven that soilorganic matter content declined relatively fast in detritus removal treatments. The reduction wasespecially remarkable in root detritus removal treatments, where – due to the lack of transpiration – soilswere moister during the whole year than in the other treatments. The higher moisture content, despite ofthe reduction of detritus input, produced an intense soil respiration. This can be explained by the fact thatdecomposing organisms have increased the use of soil organic matter. Detritus input reduction had asignificantly greater effect on soil respiration and organic matter content than detritus input duplicationof the same extent. The latter did not cause any significant change compared to the control.

  19. Carbon and nutrients output by harvesting Acacia mearnsii De Wild to four years old at the central Depression, RS

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    Marcos Vinicius Winckler Caldeira

    2014-03-01

    Full Text Available The aim of this study was to estimate the content and export of carbon, macro and micronutrients in the different components (leaf, alive and dead branch, bark, wood and roots of the Acacia mearnsii trees with 4 years old of age in Arroio dos Ratos-RS, in order to provide the forest management, based on the criterion of minimum export of nutrients. After determining the diameter distribution and its division into diameter classes (seven classes, three trees were selected in each classes. Using the 21 trees felled, the biomass of different components of trees was stimated. It was observed that wood, which represents about 64% of the biomass, contains 50% of accumulated Ca, 21% N, 27% P, 30% K, 37% Mg, 45% of S, 25% B, 37% Cu, 9% Fe, 26% Mg and 41% Zn. While the leaf, which represents 3% of total biomass, contains 20; 18; 12; 5; 10; 10; 17; 18; 5; 19 and 6% N, P, K, Ca, Mg, S, B, Cu, Fe, Mg and Zn, respectively. The export of nutrients from the crops of A. mearnsii can be minimized with retention of crop residues on the soil removal only of wood and bark.

  20. Correlation between groundwater flow and deformation in the fractured carbonate Gran Sasso aquifer (INFN underground laboratories, central Italy)

    Science.gov (United States)

    Amoruso, A.; Crescentini, L.; Martino, S.; Petitta, M.; Tallini, M.

    2014-06-01

    The Gran Sasso massif is a carbonate fractured aquifer with a spring discharge of more than 18 m3 s-1. The water table has been partially drained by two motorway tunnels and an underground laboratory (UL), located into the core aquifer. Karst features have limited role below the water table, where groundwater flow is mainly regulated by the fracture network. Two paired laser extensometers (BA and BC) recorded ground deformation in the UL. Changes in deformation correlate with the seasonal recharge/discharge cycle of groundwater flow and its long-term changes. Hydrostatic conditions prevail during the recharge phases because of the low permeability of local fractures, favoring compression, and hydraulic gradient increase above the UL. Fast groundwater flow through the high-permeability fault outcropping in the UL can enhance local dilatation for short periods. Spring discharge during exhaustion periods is fed by the low-permeability fracture network, fostering hydrodynamic conditions by hydraulic gradient decrease, diminishing compression and consequently favoring dilatation. Independent support to this conceptual model comes from local tests and a numerical model which highlights the hydromechanical strain effects induced by the hydrological cycle on the jointed rock mass along BA and the role of the hydraulic gradient on the rock mass deformation.

  1. Soil carbon storage as influenced by tree cover in the Dehesa cork oak silvopasture of central-western Spain.

    Science.gov (United States)

    Howlett, David Scott; Moreno, Gerardo; Mosquera Losada, Maria Rosa; Nair, P K Ramachandran; Nair, Vimala D

    2011-07-01

    The extent of carbon (C) stored in soils depends on a number of factors including soil characteristics, climatic and other environmental conditions, and management practices. Such information, however, is lacking for silvopastoral systems in Spain. This study quantified the amounts of soil C stored at various depths (0-25, 25-50, 50-75, and 75-100 cm) under a Dehesa cork oak (Quercus suber L.) silvopasture at varying distances (2, 5, and 15 m) to trees. Soil C in the whole soil and three soil fractions (cork oak was 50.2, 37, and 26.5 Mg ha(-1), respectively. Taking into account proportions of land surface area containing these C stocks at varying distances to trees to 1 m depth, with a tree density of 35 stems ha(-1), estimated landscape soil C is 29.9 Mg ha(-1). Greater soil C stocks directly underneath the tree canopy suggest that maintaining or increasing tree cover, where lost from disease or management, may increase long term storage of soil C in Mediterranean silvopastoral systems. The results also demonstrate the use of soil aggregate characteristics as better indicators of soil C sequestration potential and thus a tool for environmental monitoring.

  2. Secondary minerals of weathered orpiment-realgar-bearing tailings in Shimen carbonate-type realgar mine, Changde, Central China

    Science.gov (United States)

    Zhu, Xiangyu; Wang, Rucheng; Lu, Xiancai; Liu, Huan; Li, Juan; Ouyang, Bingjie; Lu, Jianjun

    2015-02-01

    The formation and dissolution of arsenic minerals commonly controls the mobility of As in sulfide mines. Here, we present the results of research based on X-ray powder diffraction (XRD), Raman microprobe spectrum, scanning electron microscope (SEM), and transmission electron microscope (TEM) analyses, Scanning transmission X-ray microscope (STXM) and X-ray absorption fine structure (XAFS) analyses to further understand the weathering of orpiment- and realgar-bearing tailings from the Shimen realgar deposit, the largest realgar deposit in Asia. These analyses indicate that four different types of As-bearing secondary minerals are present in the tailings, including arsenic oxides, arsenates, As-gypsum, and As-Fe minerals, and that arsenic in the tailings is present in +3 and +5 valence states. The precipitation of arsenates is attributed to the interaction between As-enriched run-off waters and carbonate minerals. The Ca-arsenates in the tailings are dominantly weilite and pharmacolite, both of which have Ca/As atomic ratios of 1. In addition, SO4 2-/HAsO4 2- substitution in gypsum is another important mechanism of arsenic precipitation.

  3. Sustainable biochar effects for low carbon crop production: A 5-crop season field experiment on a low fertility soil from Central China

    Science.gov (United States)

    Liu, X.

    2014-12-01

    Biochar's effects on improving soil fertility, enhancing crop productivity and reducing greenhouse gases (GHGs) emission from croplands had been well addressed in numerous short-term experiments with biochar soil amendment (BSA) mostly in a single crop season / cropping year. However, the persistence of these effects, after a single biochar application, has not yet been well known due to limited long-term field studies so far. Large scale BSA in agriculture is often commented on the high cost due to large amount of biochar in a single application. Here, we try to show the persistence of biochar effects on soil fertility and crop productivity improvement as well as GHGs emission reduction, using data from a field experiment with BSA for 5 crop seasons in central North China. A single amendment of biochar was performed at rates of 0 (C0), 20 (C20) and 40 t ha-1 (C40) before sowing of the first crop season. Emissions of CO2, CH4 and N2O were monitored with static closed chamber method throughout the crop growing season for the 1st, 2nd and 5th cropping. Crop yield was measured and topsoil samples were collected at harvest of each crop season. BSA altered most of the soil physic-chemical properties with a significant increase over control in soil organic carbon (SOC) and available potassium (K) content. The increase in SOC and available K was consistent over the 5 crop seasons after BSA. Despite a significant yield increase in the first maize season, enhancement of crop yield was not consistent over crop seasons without corresponding to the changes in soil nutrient availability. BSA did not change seasonal total CO2 efflux but greatly reduced N2O emissions throughout the five seasons. This supported a stable nature of biochar carbon in soil, which played a consistent role in reducing N2O emission, which showed inter-annual variation with changes in temperature and soil moisture conditions. The biochar effect was much more consistent under C40 than under C20 and with

  4. Field Demonstration of Horizontal Infill Drilling Using Cost-effective Integrated Reservoir Modeling--Mississippian Carbonates, Central Kansas

    Energy Technology Data Exchange (ETDEWEB)

    Saibal Bhattacharya

    2005-08-31

    Mississippian carbonate reservoirs have produced in excess of 1 billion barrels of oil in Kansas accounting for over 16% of the state's production. With declining production from other age reservoirs, the contribution of Mississippian reservoirs to Kansas's oil production has risen to 43% as of 2004. However, solution-enhanced features such as vertical shale intervals extending from the karst erosional surface at the top introduce complexities/compartmentalizations in Mississippian carbonate reservoirs. Coupled with this, strong water drives charge many of these reservoirs resulting in limited drainage from vertical wells due to high water cuts after an initial period of low water production. Moreover, most of these fields are operated by small independent operators without access to the knowledge bank of modern research in field characterization and exploitation/development practices. Thus, despite increasing importance of Mississippian fields to Kansas production, these fields are beset with low recovery factors and high abandonment rates leaving significant resources in the ground. Worldwide, horizontal infill wells have been successful in draining compartmentalized reservoirs with limited pressure depletion. The intent of this project was to demonstrate the application of horizontal wells to successfully exploit the remaining potential in mature Mississippian fields of the mid-continent. However, it is of critical importance that for horizontal wells to be economically successful, they must be selectively targeted. This project demonstrated the application of initial and secondary screening methods, based on publicly available data, to quickly shortlist fields in a target area for detailed studies to evaluate their potential to infill horizontal well applications. Advanced decline curve analyses were used to estimate missing well-level production data and to verify if the well produced under unchanging bottom-hole conditions--two commonly occurring

  5. Carbon monoxide induced erythroid differentiation of K562 cells mimics the central macrophage milieu in erythroblastic islands.

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    Shlomi Toobiak

    Full Text Available Growing evidence supports the role of erythroblastic islands (EI as microenvironmental niches within bone marrow (BM, where cell-cell attachments are suggested as crucial for erythroid maturation. The inducible form of the enzyme heme oxygenase, HO-1, which conducts heme degradation, is absent in erythroblasts where hemoglobin (Hb is synthesized. Yet, the central macrophage, which retains high HO-1 activity, might be suitable to take over degradation of extra, harmful, Hb heme. Of these enzymatic products, only the hydrophobic gas molecule--CO can transfer from the macrophage to surrounding erythroblasts directly via their tightly attached membranes in the terminal differentiation stage.Based on the above, the study hypothesized CO to have a role in erythroid maturation. Thus, the effect of CO gas as a potential erythroid differentiation inducer on the common model for erythroid progenitors, K562 cells, was explored. Cells were kept under oxygen lacking environment to mimic BM conditions. Nitrogen anaerobic atmosphere (N₂A served as control for CO atmosphere (COA. Under both atmospheres cells proliferation ceased: in N₂A due to cell death, while in COA as a result of erythroid differentiation. Maturation was evaluated by increased glycophorin A expression and Hb concentration. Addition of 1%CO only to N₂A, was adequate for maintaining cell viability. Yet, the average Hb concentration was low as compared to COA. This was validated to be the outcome of diversified maturation stages of the progenitor's population.In fact, the above scenario mimics the in vivo EI conditions, where at any given moment only a minute portion of the progenitors proceeds into terminal differentiation. Hence, this model might provide a basis for further molecular investigations of the EI structure/function relationship.

  6. Tectonics vs. eustasy: Mid Pennsylvanian carbonate-ramp cycles, ancestral Rocky Mountains, north-central New Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Wiberg, T.L. (PRC Environmental Management, Inc., Chicago, IL (United States). Dept. of Geology); Smith, G.A. (Univ. of Mexico, Albuquerque, NM (United States). Dept. of Geology)

    1992-01-01

    Detailed stratigraphic and sedimentologic analysis of measured sections within the Madera Limestone in the Sandia Mountains, New Mexico, characterize depositional environments and transgressive-regressive (T-R) cycles across a west-dipping ramp, situated approximately 70 kilometers west of the Pedernal uplift, a tectonically active element of the Ancestral Rocky Mountains. The ramp setting was separated from the Pedernal Uplift by the deep, clastic-filled Estancia Basin. T-R cycles are 2--12 meters thick and consist of asymmetric, shoaling-upward calcareous shales, thick skeletal wackestones, packstones-grainstones, and are capped by subaerial exposure surfaces or terrigenous clastics. The presence of subaerial exposure features upon subtidal carbonates argues for an allogenic control on cycle formation. 15 T-R cycles are interpreted to coincide with 3rd-order eustatic curves of Ross and Ross (1987). Following the convention of most workers, these 3rd-order cycles are herein referred to as 4th-order. No higher-order cycles have been recognized. Cycles exhibit a bundling of 4, 4th-order cycles into larger, asymmetric 3rd-order cycles, similar in pattern to those described by Ross and Ross (1987). Correlation of Madera Limestone cycles with those in other regions indicates that ancestral Rocky Mountains tectonism was less effective than eustasy in controlling the stratigraphy of Middle Pennsylvanian sediments. Using various time scales for the Desmoinesian, cycle periodicities range between 200,000--370,000 years. This average cycle periodicity is similar to other 4th-order cycles reported in the literature for the Pennsylvanian and suggests a Milankovitch orbital forcing mechanism.

  7. Pathway of EPC Model of Central Construction Companies%中央建筑企业EPC总承包发展模式的途径研究

    Institute of Scientific and Technical Information of China (English)

    姜龑

    2012-01-01

    在我国工程建设领域,为了适应形势发展的需要,EPC总承包模式应运而生.本文针对当前中央建筑企业发展EPC总承包模式面临的主要问题进行分析,并提出了发展该模式的有效途径.%In the field of engineering construction, in order to adapt to the needs of development, EPC model comes into being. This paper analyzes the main problems of EPC model faced by central construction companies and proposes an effective way to develop the model.

  8. Ca-rich carbonates associated with ultrabasic-ultramafic melts: Carbonatite or limestone xenoliths? A case study from the late Miocene Morron de Villamayor volcano (Calatrava Volcanic Field, central Spain)

    Science.gov (United States)

    Lustrino, Michele; Prelević, Dejan; Agostini, Samuele; Gaeta, Mario; Di Rocco, Tommaso; Stagno, Vincenzo; Capizzi, Luca Samuele

    2016-07-01

    The volcanic products of the late Miocene Morron de Villamayor volcano (Calatrava Volcanic Field, central Spain) are known for being one of the few outcrops of leucitites in the entire circum-Mediterranean area. These rocks are important because aragonite of mantle origin has been reported as inclusion in olivine macrocrysts. We use petrographic observations, mineral compositions, as well as oxygen and carbon isotope ratios coupled with experimental petrology to understand the origin of carbonate phase in these olivine-phyric rocks. Groundmass and macrocryst olivines range from δ18OVSMOW of +4.8‰, typical of mantle olivine values, to +7.4‰, indicating contamination by sedimentary carbonate. Carbonates are characterized by heavy oxygen isotope compositions (δ18OVSMOW >+24‰), and relatively light carbon isotopes (δ13CPDB <-11‰), resembling skarn values, and distinct from typical mantle carbonatite compositions. Petrography, mineral compositions such as low Mg# of clinopyroxene and biotite, low Ca# and low incompatible element abundance of the carbonate, and isotopic ratios of O and C, do not support a mantle origin for the carbonate. Rather, the carbonate inclusions found in the olivine macrocrysts are interpreted as basement limestone fragments entrapped by the rising crystallizing magma. Comparison with experimental carbonatitic and silicate-carbonatitic melts indicates that low-degree partial melts of a carbonated peridotite must have a dolomitic rather than the aragonitic/calcitic composition as those found trapped in the Morron de Villamayor olivine macrocrysts.

  9. Sedimentary environments and stratigraphy of the carbonate-silicilastic deposits of the Shirgesht Formation: implications for eustasy and local tectonism in the Kalmard Block, Central Iran

    Directory of Open Access Journals (Sweden)

    aram bayetgoll

    2015-10-01

    Full Text Available Introduction   Sedimentological and sequence stratigraphic analysis providing insight into the main relationships between sequence architecture and stacking pattern, syn/post-depositional tectonics, and eustatic sea-level fluctuations (Gawthorpe and Leeder 2000; Zecchin et al. 2003, 2004; Carpentier et al. 2007. Relative variations in sea level are due to tectonic activity and eustasy. The Shirgesht Formation in the Kalmard Block of Central Iran provides a useful case study for to determine the processes responsible on internal architecture and stacking pattern of depositional sequences in a half-graben basin. In the Shirgesht Formation, siliciclastic and carbonate successions of the Kalmard Basin, the cyclic stratigraphic record is the result of the complex interaction of regional uplift, eustasy, local tectonics, sediment supply, and sedimentary processes (Bayet-Goll 2009, 2014; Hosseini-Barzi and Bayet-Goll 2009.     Material & Methods   Lower Paleozoic successions in Tabas and Kalmard blocks from Central Iran share the faunal and floral characteristics with other Gondwana sectors such as south-western Europe and north Africa–Middle East (Ghaderi et al. 2009. The geology of these areas was outlined by Ruttner et al. (1968 and by Bruton et al. (2004. The Cambrian-Middle Triassic strata in the Kalmard Block were deposited in a shallow water platform that possesses lithologic dissimilarities with the Tabas area (Aghanabati 2004. The occurrence of two active faults indicates clearly that Kalmard basin formed a mobile zone throughout the Paleozoic so that lithostratigraphic units show considerably contrasting facies in comparison with Tabas basin (Hosseini-Barzi and Bayet-Goll 2009; Bayet-Goll 2014 . The Shirgesht Formation in the Block Kalmard is mainly composed of carbonate-siliciclastic successions that disconformability overlain Kalmard Formation (attributed to Pre-Cambrian and is underlain by Gachal (Carboniferous or Rahdar (Devonian

  10. Measuring and modeling C flux rates through the central metabolic pathways in microbial communities using position-specific 13C-labeled tracers

    Science.gov (United States)

    Dijkstra, P.; van Groenigen, K.; Hagerty, S.; Salpas, E.; Fairbanks, D. E.; Hungate, B. A.; KOCH, G. W.; Schwartz, E.

    2012-12-01

    The production of energy and metabolic precursors occurs in well-known processes such as glycolysis and Krebs cycle. We use position-specific 13C-labeled metabolic tracers, combined with models of microbial metabolic organization, to analyze the response of microbial community energy production, biosynthesis, and C use efficiency (CUE) in soils, decomposing litter, and aquatic communities. The method consists of adding position-specific 13C -labeled metabolic tracers to parallel soil incubations, in this case 1-13C and 2,3-13C pyruvate and 1-13C and U-13C glucose. The measurement of CO2 released from the labeled tracers is used to calculate the C flux rates through the various metabolic pathways. A simplified metabolic model consisting of 23 reactions is solved using results of the metabolic tracer experiments and assumptions of microbial precursor demand. This new method enables direct estimation of fundamental aspects of microbial energy production, CUE, and soil organic matter formation in relatively undisturbed microbial communities. We will present results showing the range of metabolic patterns observed in these communities and discuss results from testing metabolic models.

  11. Interaction between hydrogen sulfide/cystathionine γ-lyase and carbon monoxide/heme oxygenase pathways in aortic smooth muscle cells

    Institute of Scientific and Technical Information of China (English)

    Hong-fang JIN; Jun-bao DU; Xiao-hui LI; Yan-fei WANG; Yin-fang LIANG; Chao-shu TANG

    2006-01-01

    Aim: To investigate the interaction between hydrogen sulfide (H2S)/cystathionine γ-lyase (CSE) and carbon monoxide (CO)/heme oxygenase (HO) pathways in aortic smooth muscle cells (ASMC). Methods: The ASMCs were divided into the following groups: (1) the control group; (2) the zinc protoporphyrin (ZnPP) 20 (μmol/L group; (3) the propargylglycine (PPG) 2 mmol/L, 4 mmol/L and 10 mmol/L groups; and (4) the sodium hydrosulfide (NaHS) 1×10-5 mol/L, 1×10-4 mol/L and 1×10-3 mol/L groups. Each of the groups was further divided into 6 h, 12 h, 18 h and 24 h subgroups. The CO level, represented by carboxyhemoglobin (HbCO) content was measured using a spectrophotometric method and H2S content was detected by a sensitive electrode method. CSE and HO-1 expressions were detected by Western blotting. Results: The H2S content in the medium and CSE expression by ASMC were markedly increased by ZnPP compared with the control group. HbCO content in the medium and HO-1 expression by the ASMC started strengthening following 24 h treatment with PPG at 2 mmol/L, but were further strengthened following 18 h and 24 h treatment with PPG at 4 mmol/L compared with the controls (P<0.01). PPG at 10 mmol/L increased the HbCO level in the medium following 18 h treatment and increased HO-1 expression by the ASMC following 12 h treatment. Moreover, NaHS at 1×10-5 mol/L and 1×10-4 mol/L decreased the HbCO level in the medium and HO-1 expression by the ASMC after 6 h and 12 h treatment, while NaHS at 1×10-3 mol/L decreased them at all time points of the treatments. Conclusion: The results suggested that endogenous CO/HO and H2S/CSE pathways inhibited each other in ASMC under physiological conditions.

  12. Factors promoting larch dominance in central Siberia: fire versus growth performance and implications for carbon dynamics at the boundary of evergreen and deciduous conifers

    Directory of Open Access Journals (Sweden)

    E.-D. Schulze

    2012-04-01

    Full Text Available The relative role of fire and of climate in determining canopy species composition and aboveground carbon stocks were investigated. Measurements were made along a transect extending from the dark taiga zone of central Siberia, where Picea and Abies dominate the canopy, into the Larix zone of eastern Siberia. We test the hypotheses that the change in canopy species composition is based (1 on climate-driven performance only, (2 on fire only, or (3 on fire-performance interactions. We show that the evergreen conifers Picea obovata and Abies sibirica are the natural late-successional species both in central and eastern Siberia, provided there has been no fire for an extended period of time. There are no changes in performance of the observed species along the transect. Fire appears to be the main factor explaining the dominance of Larix and of soil carbon. Of lesser influence were longitude as a proxy for climate, local hydrology and active-layer thickness. We can only partially explain fire return frequency, which is not only related to climate and land cover, but also to human behavior.

    Stand-replacing fires decreased from 300 to 50 yrs between the Yenisei Ridge and the upper Tunguska. Repeated non-stand-replacing surface fires eliminated the regeneration of Abies and Picea. With every 100 yrs since the last fire, the percentage of Larix decreased by 20%.

    Biomass of stems of single trees did not show signs of age-related decline. Relative diameter increment was 0.41 ± 0.20% at breast height and stem volume increased linearly over time with a rate of about 0.36 t C ha−1 yr−1 independent of age class and species. Stand biomass reached about 130 t C ha−1(equivalent to about 520 m3 ha−1. Individual trees of Larix were older than 600 yrs. The maximum age and biomass seemed to be limited by fungal rot of

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

    Science.gov (United States)

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

    1979-01-01

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

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

    Science.gov (United States)

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

    2013-01-01

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

  15. Most Blood Biomarkers Related to Vitamin Status, One-Carbon Metabolism, and the Kynurenine Pathway Show Adequate Preanalytical Stability and Within-Person Reproducibility to Allow Assessment of Exposure or Nutritional Status in Healthy Women and Cardiovascular Patients123

    OpenAIRE

    Midttun, Øivind; Townsend, Mary K.; Nygård, Ottar; Tworoger, Shelley S.; Brennan, Paul; Johansson, Mattias; Ueland, Per Magne

    2014-01-01

    Knowledge of stability during sample transportation and changes in biomarker concentrations within person over time are paramount for proper design and interpretation of epidemiologic studies based on a single measurement of biomarker status. Therefore, we investigated stability and intraindividual vs. interindividual variation in blood concentrations of biomarkers related to vitamin status, one-carbon metabolism, and the kynurenine pathway. Whole blood (EDTA and heparin, n = 12) was stored w...

  16. Using an explicit emission tagging method in global modeling of source-receptor relationships for black carbon in the Arctic: Variations, sources, and transport pathways

    Science.gov (United States)

    Wang, Hailong; Rasch, Philip J.; Easter, Richard C.; Singh, Balwinder; Zhang, Rudong; Ma, Po-Lun; Qian, Yun; Ghan, Steven J.; Beagley, Nathaniel

    2014-11-01

    We introduce an explicit emission tagging technique in the Community Atmosphere Model to quantify source-region-resolved characteristics of black carbon (BC), focusing on the Arctic. Explicit tagging of BC source regions without perturbing the emissions provides a physically consistent and computationally efficient approach to establish source-receptor relationships and transport pathways. Our analysis shows that the contributions of major source regions to the global BC burden are not proportional to the respective emissions due to strong region-dependent removal rates and lifetimes, while the contributions to BC direct radiative forcing show a near-linear dependence on their respective contributions to the burden. Arctic BC concentrations, deposition, and source contributions all have strong seasonal variations. Eastern Asia contributes the most to the wintertime Arctic BC burden, but has much less impact on lower-level concentrations and deposition. Northern Europe emissions are more important to both surface concentration and deposition in winter than in summer. The largest contribution to Arctic BC in the summer is from Northern Asia. Although local emissions contribute less than 10% to the annual mean BC burden and deposition within the Arctic, the per-emission efficiency is much higher than for non-Arctic sources. The interannual variability (1996-2005) due to meteorology is small in annual mean BC burden and radiative forcing but is significant in yearly seasonal means over the Arctic. When a slow aging treatment of BC is introduced, the increase of BC lifetime and burden is source dependent. Global BC forcing-per-burden efficiency also increases primarily due to changes in BC vertical distributions.

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

    Directory of Open Access Journals (Sweden)

    Vijayalakshmi Varma

    2015-06-01

    Full Text Available Increased consumption of sugar and fructose as sweeteners has resulted in the utilization of fructose as an alternative metabolic fuel that may compete with glucose and alter its metabolism. To explore this, human Simpson-Golabi-Behmel Syndrome (SGBS preadipocytes were differentiated to adipocytes in the presence of 0, 1, 2.5, 5 or 10 mM of fructose added to a medium containing 5 mM of glucose representing the normal blood glucose concentration. Targeted tracer [1,2-13C2]-d-glucose fate association approach was employed to examine the influence of fructose on the intermediary metabolism of glucose. Increasing concentrations of fructose robustly increased the oxidation of [1,2-13C2]-d-glucose to 13CO2 (p < 0.000001. However, glucose-derived 13CO2 negatively correlated with 13C labeled glutamate, 13C palmitate, and M+1 labeled lactate. These are strong markers of limited tricarboxylic acid (TCA cycle, fatty acid synthesis, pentose cycle fluxes, substrate turnover and NAD+/NADP+ or ATP production from glucose via complete oxidation, indicating diminished mitochondrial energy metabolism. Contrarily, a positive correlation was observed between glucose-derived 13CO2 formed and 13C oleate and doses of fructose which indicate the elongation and desaturation of palmitate to oleate for storage. Collectively, these results suggest that fructose preferentially drives glucose through serine oxidation glycine cleavage (SOGC pathway one-carbon cycle for NAD+/NADP+ production that is utilized in fructose-induced lipogenesis and storage in adipocytes.

  18. Identification of putative RuBisCo activase (TaRca1 ˗ the catalytic chaperone regulating carbon assimilatory pathway in wheat (Triticum aestivum under the heat stress

    Directory of Open Access Journals (Sweden)

    RANJEET RANJAN KUMAR

    2016-07-01

    Full Text Available RuBisCo activase (Rca is a catalytic chaperone involved in modulating the activity of RuBisCo (key enzyme of photosynthetic pathway. Here, we identified eight novel transcripts from wheat through data mining predicted to be Rca and cloned a transcript of 1.4 kb from cv. HD2985, named as TaRca1 (GenBank acc. no. KC776912. Single copy number of TaRca1 was observed in wheat genome. Expression analysis in diverse wheat genotypes (HD2985, Halna, PBW621 and HD2329 showed very high relative expression of TaRca1 in Halna under control and HS-treated, as compared to other cultivars at different stages of growth. TaRca1 protein was predicted to be chloroplast-localized with numerous potential phosphorylation sites. Nothern blot analysis showed maximum accumulation of TaRca1 transcript in thermotolerant cv. during mealy-ripe stage, as compared to thermosusceptible. Decrease in the photosynthetic parameters was observed in all the cultivars, except PBW621 in response to HS. We observed significant increase in the Rca activity in all the cultivars under HS at different stages of growth. HS causes decrease in the RuBisCo activity; maximum reduction was observed during pollination stage in thermosusceptible cvs. as validated through immunoblotting. We observed uniform carbon distribution in different tissues of thermotolerant cvs., as compared to thermosusceptible. Similarly, tolerance level of leaf was observed maximum in Halna having high Rca activity under HS. A positive correlation was observed between the transcript and activity of TaRca1 in HS-treated Halna. Similarly, TaRca1 enzyme showed positive correlation with the activity of RuBisCo. There is, however, need to manipulate the thermal stability of TaRca1 enzyme through protein engineering for sustaining the photosynthetic rate under HS – a novel approach towards development of ‘climate-smart’ crop.

  19. Tropical forest carbon balance: effects of field- and satellite-based mortality regimes on the dynamics and the spatial structure of Central Amazon forest biomass

    International Nuclear Information System (INIS)

    Debate continues over the adequacy of existing field plots to sufficiently capture Amazon forest dynamics to estimate regional forest carbon balance. Tree mortality dynamics are particularly uncertain due to the difficulty of observing large, infrequent disturbances. A recent paper (Chambers et al 2013 Proc. Natl Acad. Sci. 110 3949–54) reported that Central Amazon plots missed 9–17% of tree mortality, and here we address ‘why’ by elucidating two distinct mortality components: (1) variation in annual landscape-scale average mortality and (2) the frequency distribution of the size of clustered mortality events. Using a stochastic-empirical tree growth model we show that a power law distribution of event size (based on merged plot and satellite data) is required to generate spatial clustering of mortality that is consistent with forest gap observations. We conclude that existing plots do not sufficiently capture losses because their placement, size, and longevity assume spatially random mortality, while mortality is actually distributed among differently sized events (clusters of dead trees) that determine the spatial structure of forest canopies. (paper)

  20. A hybrid model of support vector regression with genetic algorithm for forecasting adsorption of malachite green onto multi-walled carbon nanotubes: central composite design optimization.

    Science.gov (United States)

    Ghaedi, M; Dashtian, K; Ghaedi, A M; Dehghanian, N

    2016-05-11

    The aim of this work is the study of the predictive ability of a hybrid model of support vector regression with genetic algorithm optimization (GA-SVR) for the adsorption of malachite green (MG) onto multi-walled carbon nanotubes (MWCNTs). Various factors were investigated by central composite design and optimum conditions was set as: pH 8, 0.018 g MWCNTs, 8 mg L(-1) dye mixed with 50 mL solution thoroughly for 10 min. The Langmuir, Freundlich, Temkin and D-R isothermal models are applied to fitting the experimental data, and the data was well explained by the Langmuir model with a maximum adsorption capacity of 62.11-80.64 mg g(-1) in a short time at 25 °C. Kinetic studies at various adsorbent dosages and the initial MG concentration show that maximum MG removal was achieved within 10 min of the start of every experiment under most conditions. The adsorption obeys the pseudo-second-order rate equation in addition to the intraparticle diffusion model. The optimal parameters (C of 0.2509, σ(2) of 0.1288 and ε of 0.2018) for the SVR model were obtained based on the GA. For the testing data set, MSE values of 0.0034 and the coefficient of determination (R(2)) values of 0.9195 were achieved. PMID:27119755

  1. Studies of palaeovegetation changes in the Central Amazon by carbon isotopes (12C, 13C, 14C) of soil organic matter

    International Nuclear Information System (INIS)

    The paper presents carbon isotope data δ13C and 14C on soil organic matter collected along an ecosystem transect in southern Amazon state, north-central Amazon region, that includes three distinct vegetation communities: savannah (Campos de Humaita), a savannah-forest transition and forest (Manaus). The study sites are located along road BR 319. Botanical identification and 13C analysis of modern vegetation in the savannah and forest sites indicate that most of the vegetation is C3 plants, although a few C4 plants are present at Campos de Humaita. The 13C and 14C data for soil organic matter in the Humaita region show that significant vegetation changes have occurred in the past, probably associated with climatic changes. During the early Holocene, forest vegetation extended throughout the study region, including areas occupied today by savannah vegetation. Savannah vegetation expanded at least 2 km into the modern forest ecotone during the middle Holocene, suggesting drier conditions. The last approximately 1000 years appear to indicate a recent expansion of forest vegetation, reflecting a return to a more moist climate. The study illustrates that the transition area between forest and savannah vegetation is quite sensitive to climatic changes, and this region should be the focus of more extensive research related to past climate and vegetation dynamics in the Amazon region. (author)

  2. Palaeogeographic evolution of the marine Middle Triassic marine Germanic Basin changements - With emphasis on the carbonate tidal flat and shallow marine habitats of reptiles in Central Pangaea

    Science.gov (United States)

    Diedrich, Cajus G.

    2009-01-01

    More than seventy-five vertebrate track-sites have been found in Central Europe in 243-246.5 m.y. old Triassic coastal intertidal to sabkha carbonates. In the western part of the very flat Triassic intracontinental Germanic Basin, the carbonate strata contain at least 22 laterally extensive track horizons (called megatracksites). In contrast, in the eastern part of the basin only six megatracksites extended to near the centre of the Basin during marine low stands. Marine ingression and the development of extensive coastal marine environments began during the Aegean (Anisian) stage. This incursion began in the region of the eastern Carpathian and Silesian gates and spread westward due to the development of a tectonically controlled intracratonic basin. The tectonic origin of this basin made it susceptible to tsunamis and submarine earthquakes, which constituted very dangerous hazards for coastal terrestrial and even marine reptiles. The shallow sea that spread across the Germanic Basin produced extensive tidal flats that at times formed extensive inter-peninsular bridges between the Rhenish and Bohemian Massifs. The presence of these inter-peninsular bridges explains the observed distribution and movement of reptiles along coastal Europe and the northern Tethys Seaway during the Middle Triassic epoch. Two small reptiles, probably Macrocnemus and Hescherleria, left millions of tracks and trackways known as Rhynchosauroides and Procolophonichnium in the Middle Triassic coastal intertidal zone. The great abundance of their tracks indicates that their trackmakers Macrocnemus and Hescherleria were permanent inhabitants of this environment. In sharp contrast, tracks of other large terrestrial reptiles are quite rare along the coastal margins of the Germanic Basin, for example the recently discovered archaeosaur tracks and trackways referable to Isochirotherium, which most probably were made by the carnivore Ticinosuchus. Smaller medium-sized predatory thecodont reptiles

  3. Using an Explicit Emission Tagging Method in Global Modeling of Source-Receptor Relationships for Black Carbon in the Arctic: Variations, Sources and Transport Pathways

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hailong; Rasch, Philip J.; Easter, Richard C.; Singh, Balwinder; Zhang, Rudong; Ma, Po-Lun; Qian, Yun; Ghan, Steven J.; Beagley, Nathaniel

    2014-11-27

    We introduce an explicit emission tagging technique in the Community Atmosphere Model to quantify source-region-resolved characteristics of black carbon (BC), focusing on the Arctic. Explicit tagging of BC source regions without perturbing the emissions makes it straightforward to establish source-receptor relationships and transport pathways, providing a physically consistent and computationally efficient approach to produce a detailed characterization of the destiny of regional BC emissions and the potential for mitigation actions. Our analysis shows that the contributions of major source regions to the global BC burden are not proportional to the respective emissions due to strong region-dependent removal rates and lifetimes, while the contributions to BC direct radiative forcing show a near-linear dependence on their respective contributions to the burden. Distant sources contribute to BC in remote regions mostly in the mid- and upper troposphere, having much less impact on lower-level concentrations (and deposition) than on burden. Arctic BC concentrations, deposition and source contributions all have strong seasonal variations. Eastern Asia contributes the most to the wintertime Arctic burden. Northern Europe emissions are more important to both surface concentration and deposition in winter than in summer. The largest contribution to Arctic BC in the summer is from Northern Asia. Although local emissions contribute less than 10% to the annual mean BC burden and deposition within the Arctic, the per-emission efficiency is much higher than for major non-Arctic sources. The interannual variability (1996-2005) due to meteorology is small in annual mean BC burden and radiative forcing but is significant in yearly seasonal means over the Arctic. When a slow aging treatment of BC is introduced, the increase of BC lifetime and burden is source-dependent. Global BC forcing-per-burden efficiency also increases primarily due to changes in BC vertical distributions. The

  4. Carbon dioxide-sensing in organisms and its implications for human disease

    OpenAIRE

    Cummins, Eoin P.; Selfridge, Andrew C; Sporn, Peter H.; et al

    2013-01-01

    The capacity of organisms to sense changes in the levels of internal and external gases and to respond accordingly is central to a range of physiologic and pathophysiologic processes. Carbon dioxide, a primary product of oxidative metabolism is one such gas that can be sensed by both prokaryotic and eukaryotic cells and in response to altered levels, elicit the activation of multiple adaptive pathways. The outcomes of activating CO2-sensitive pathways in various species include increased viru...

  5. Influence of domestic pets on soil concentrations of dissolved organic carbon, nitrogen, and phosphorus under turfgrass in apartment complexes of Central Texas, USA

    Science.gov (United States)

    Steele, M.; Aitkenhead-Peterson, J. A.

    2009-12-01

    High nitrogen (N) and phosphorus (P) watershed loading rates increases the concentration and loads present in urban streams and rivers, resulting in eutrophication and degradation of surface water quality. Domestic pet animal feed may represent a significant proportion of nitrogen loading in urban watersheds, and because it is deposited directly on the watershed surface may have a large effect on N loads in urban surface waters (Baker et al. 2001). Animal manure has long been used to increase soil N and phosphorus concentrations for the purpose of growing agricultural crops; however, little is known about unintentional urban manuring resulting from a high density of domesticated pets. The purpose of this study is to determine if the presence of domesticated animals in high density urban developments results in increased concentrations of soil dissolved organic carbon (DOC), N, and P and the potential to contribute to loading of urban streams. Composite soil samples from the 0 to 5 cm and 5 to 10 cm soil depth were collected from apartment complexes in Bryan/College Station (BCS) and San Antonio, Texas during August, 2009. Apartment complexes were randomly located around the city and were chosen based on their rules regarding pet ownership. Four apartment complexes that allowed all domestic pets were compared to four that did not allow any domestic pets on the property. A 10:1 water extraction of field moist soil was conducted immediately after sampling. Soil water extracts were analyzed for DOC, total dissolved nitrogen (TDN), nitrate-N, ammonium-N, dissolved organic N, and orthophosphate-P. Results indicated significantly increased concentrations of DOC and N species at both depths in BCS apartments that allowed pets compared to those that did not; however, opposite trends were found in San Antonio. There is a trend for increased concentrations of orthophosphate-P at both locations. Baker, L.A., D. Hope, Y. Xu, et al. 2001. Nitrogen balance for the central Arizona

  6. The lacustrine carbon cycle as illuminated by the waters and sediments of two hydrologically distinct headwater lakes in North-Central Minnesota, U.S.A

    Science.gov (United States)

    Dean, W.E.; Schwalb, A.

    2002-01-01

    The accumulation rates of CaCO3 and organic carbon (OC) in lake sediments are delicately balanced between production in the epilimnion and destruction in the hypolimnion. The cycling of these two forms of carbon makes a "carbon pump" that greatly affects the biogeochemical cycles of other elements. To further understand these biogeochemical dynamics, the lakes, streams, and wetlands of the Shingobee River headwater area of north-central Minnesota have been subjected to intensive hydrologic and biogeochemical studies. Williams Lake, situated close to the highest point in the regional flow system, is hydrologically closed, with no surface inlet or outlet, and ground water and precipitation as the only sources of water. Shingobee Lake, situated at the lowest point in the regional flow system, has the Shingobee River as an inlet and outlet. The surface waters of both lakes are oversaturated, and the bottom waters undersaturated, with respect to CaCO3 during the summer. The small amount of CaCO3 that is precipitated in the epilimnion of Williams Lake during the summer is dissolved in the undersaturated hypolimnion and sediments with the result that no CaCO3 is incorporated into the profundal surface sediments. Because of the high phytoplankton productivity of Shingobee Lake, sufficient CaCO3 is produced in the epilimnion that large amounts survive the corrosive hypolimnion and sediments, and an average of 46 wt. % accumulates in surface sediments. Another consequence of higher phytoplankton productivity in Shingobee Lake is that the hypolimnion becomes oxygen deficient within a month after overturn in both the spring and fall. Because of reducing conditions that develop in the hypolimnion of Shingobee Lake, high concentrations of dissolved Fe and Mn accumulate there during summer stratification. Precipitation of Fe and Mn oxyhydroxides during periods of fall and spring overturn results in high concentrations of Fe and Mn in surface sediments. In Williams Lake, high

  7. Windthrow and fallow-forest successions impacts in soil carbon stocks and GHG fluxes spatial variability and dynamics in the Central Russia' reserve spruce ecosystems

    Science.gov (United States)

    Vasenev, Ivan; Ivanov, Alexey; Komarova, Tatyana; Valentini, Riccardo

    2015-04-01

    High spatial and temporal variability is mutual feature for most forest soils that is especially obvious in case of their carbon stocks and GHG fluxes. This phenomenon is generally well-known but not so often becomes the object of special precision investigation in detail and small scales so there are still serious gaps in its principal factors understanding due to their high bioclimatic, regional, landscape, tree species and temporal variability. Southern taiga is one of the most environmentally important world zonal forest ecosystems due to its still comparatively intensive carbon biogeochemical cycle and huge area in the northern Eurasia with strong anthropogenic impacts by Western & Central European and Southern & Eastern Asian regions. Central Forest Biospheric Reserve (Tver region, 360 km to North-West from Moscow) is the principal southern-taiga reserve in the European territory of Russia. Since start of its research activity in 1939 the reserve became the regional center of mature spruce ecosystem structure and dynamics investigation. In 1970-1980-s there have been done complex investigations of windthrow soil patterns and fallow-forest successions. Since middle of 1990-s the ecosystem-level GHG fluxes have been observed by eddy covariance method. Since 2012 the detailed year-round monitoring is running in the southern-taiga zonal station of the regional system RusFluxNet with especial attention on the soil carbon stocks and GHG fluxes spatial variability and dynamics due to windthrow and fallow-forest successions (in frame of RF Governmental projects #11.G34.31.0079 and #14.120.14.4266). Soil carbon dynamics is investigated in decades-hundred-year chronosequences of dominated parcels and different-size windthrow soil cover patterns, including direct investigation during last 33 years with detailed mapping, soil profile morphometrics and bulk density, morphogenetic and statistical analysis of mass data. Morphogenetic analysis of microrelief, soil profile

  8. Long-term investigations of summertime chlorophyll a, particulate organic carbon and continuously observations of vertical particle flux in Fram Strait and the central Arctic Ocean

    Science.gov (United States)

    Nöthig, Eva-Maria; Bauerfeind, Eduard; Bracher, Astrid; Cherkasheva, Alexandra; Fahl, Kirsten; Lalande, Catherine; Metfies, Katja; Peeken, Ilka; Salter, Ian; Boetius, Antje; Soltwedel, Thomas

    2016-04-01

    The Arctic Ocean is one of the key regions where the effect of climate change is most pronounced due to massive reduction of sea ice volume and extent. Most of the sea ice is transported out of the Arctic Ocean with the cold East Greenland Current (EGC) in the western Fram Strait, while warm Atlantic water enters the Arctic Ocean with the West Spitsbergen Current (WSC) in the eastern Fram Strait. In this scenario we conducted several cruises to Fram Strait and the central Arctic Ocean (CAO) between 1991 and 2015 to monitor phytoplankton biomass, particulate organic carbon standing stocks during summer at discrete depth using water bottle samples, and the sedimentation of organic matter by means of moored sediment traps throughout the year. With our study we aim at tracing effects of environmental changes in the pelagic system and impacts on the fate of organic matter produced in the upper water column in a region that is anticipated to react rapidly to climate change. We will present data sets of phytoplankton biomass (chlorophyll a) and particulate organic carbon (POC) from the upper 100 m of the water column as well as results from vertical particle flux measurements with yearly deployed sediment traps at the LTER (Long-Term Ecological Research) observatory HAUSGARTEN in eastern Fram Strait (79°/4°E) between 2000 and 2012 and from two locations in the CAO close to the Lomonosov Ridge (1995/96) and the Gakkel Ridge (2011/12). Analyses of the material collected by the sediment traps allowed us to track seasonal and inter-annual changes in the upper water column at HAUSGARTEN and in the CAO. Whereas chlorophyll a (integrated values 0 -100 m) showed only a slight increase in eastern Fram Strait, it stayed more or less constant in the CAO and western Fram Strait, with the exception of 2015 exhibiting less biomass during late summer in the CAO. Highest biomass was found in the eastern Fram Strait and lowest in the heavily ice-covered regions. POC distribution

  9. Relationship between fracturing and porogenesis in a carbonate reservoir: Example from the Middle Turonian Bireno Member in Jebel M'rhila, Central Tunisia

    Science.gov (United States)

    Haj Ali, Hajer; Belghithi, Hanen; Ouali, Jamel Abdennaceur; Touir, Jamel

    2016-09-01

    The aim of the present work is to study the Middle Turonian carbonate Bireno Member in Jebel M'rhila area (Central Tunisia). This member mainly consists of dolostones. The sampling of the dolomitic rocks was carried out on both sides of the several fractures affecting the Bireno Member. We also measured the directions and dips of the fractures. The Studied dolomites basically consist of subhedral to euhedral dolospar. The porosity associated to the dolomites show a gradual variation both laterally and vertically. In fact, porosity increases respectively, laterally while going toward the fractures and vertically from the bottom to the top of the dolomitic member. The mineralogical and geochemical analyses of dolomite, carried out respectively by X-Ray Diffraction and Atomic Absorption, show that the studied dolomites broadly range from a sub-stoechiometric dolomite (48% CaCO3) far from the fractures to a dolomitic calcite (84% CaCO3) near the fractures. In the same way, the MgCO3 contents vary from 35% to 11%. Such high contents in Ca against low contents in Mg could probably related to the dilution of the dolomitizing marine waters by meteoric waters which would have been introduced within the platform during the Middle Turonian sea-level fall and the subsequent subaerial exposure of the Bireno platform. The Sr and Na contents (respectively, 4 ppm and 15 ppm in average) are rather low and they gradually decrease while approaching the fractures. Such a gradual decrease in Sr and Na concentrations may be the result of salinity lowering caused by the meteoric waters that would have circulated through the existing fractures networks. The previous analyses were supplemented by the SEM examination of the dolomite and the measurement of porosity and permeability. The SEM allowed us to identify the dolomite petrographic phases and the associated diagenetic products (solution, cementing, dedolomitization.), whereas the porosity and permeability evaluation highlights the

  10. Reaction pathways of the dissociation of methylal: A DFT study

    Energy Technology Data Exchange (ETDEWEB)

    Frey, H.-M.; Beaud, P.; Gerber, T.; Mischler, B.; Radi, P.P.; Tzannis, A.-P. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    Schemata for modelling combustion processes do not yet include reaction rates for oxygenated fuels like methylal (DMM) which is considered as an additive or replacement for diesel due to its low sooting propensity. Density functional theory (DFT) studies of the possible reaction pathways for different dissociation steps of methylal are presented. Cleavage of a hydrogen bond to the methoxy group or the central carbon atom were simulated at the BLYP/6-311++G{sup **} level of theory. The results are compared to the experiment when dissociating and/or ionising DMM with femtosecond pulses. (author) 1 fig., 1 tab., 1 ref.

  11. Rhamnolipids elicit defense responses and induce disease resistance against biotrophic, hemibiotrophic, and necrotrophic pathogens that require different signaling pathways in Arabidopsis and highlight a central role for salicylic acid.

    Science.gov (United States)

    Sanchez, Lisa; Courteaux, Barbara; Hubert, Jane; Kauffmann, Serge; Renault, Jean-Hugues; Clément, Christophe; Baillieul, Fabienne; Dorey, Stéphan

    2012-11-01

    Plant resistance to phytopathogenic microorganisms mainly relies on the activation of an innate immune response usually launched after recognition by the plant cells of microbe-associated molecular patterns. The plant hormones, salicylic acid (SA), jasmonic acid, and ethylene have emerged as key players in the signaling networks involved in plant immunity. Rhamnolipids (RLs) are glycolipids produced by bacteria and are involved in surface motility and biofilm development. Here we report that RLs trigger an immune response in Arabidopsis (Arabidopsis thaliana) characterized by signaling molecules accumulation and defense gene activation. This immune response participates to resistance against the hemibiotrophic bacterium Pseudomonas syringae pv tomato, the biotrophic oomycete Hyaloperonospora arabidopsidis, and the necrotrophic fungus Botrytis cinerea. We show that RL-mediated resistance involves different signaling pathways that depend on the type of pathogen. Ethylene is involved in RL-induced resistance to H. arabidopsidis and to P. syringae pv tomato whereas jasmonic acid is essential for the resistance to B. cinerea. SA participates to the restriction of all pathogens. We also show evidence that SA-dependent plant defenses are potentiated by RLs following challenge by B. cinerea or P. syringae pv tomato. These results highlight a central role for SA in RL-mediated resistance. In addition to the activation of plant defense responses, antimicrobial properties of RLs are thought to participate in the protection against the fungus and the oomycete. Our data highlight the intricate mechanisms involved in plant protection triggered by a new type of molecule that can be perceived by plant cells and that can also act directly onto pathogens. PMID:22968829

  12. The Entner–Doudoroff pathway is an overlooked glycolytic route in cyanobacteria and plants

    Science.gov (United States)

    Chen, Xi; Schreiber, Karoline; Appel, Jens; Makowka, Alexander; Fähnrich, Berit; Roettger, Mayo; Hajirezaei, Mohammad R.; Sönnichsen, Frank D.; Schönheit, Peter; Martin, William F.; Gutekunst, Kirstin

    2016-01-01

    Glucose degradation pathways are central for energy and carbon metabolism throughout all domains of life. They provide ATP, NAD(P)H, and biosynthetic precursors for amino acids, nucleotides, and fatty acids. It is general knowledge that cyanobacteria and plants oxidize carbohydrates via glycolysis [the Embden–Meyerhof–Parnas (EMP) pathway] and the oxidative pentose phosphate (OPP) pathway. However, we found that both possess a third, previously overlooked pathway of glucose breakdown: the Entner–Doudoroff (ED) pathway. Its key enzyme, 2-keto-3-deoxygluconate-6-phosphate (KDPG) aldolase, is widespread in cyanobacteria, moss, fern, algae, and plants and is even more common among cyanobacteria than phosphofructokinase (PFK), the key enzyme of the EMP pathway. Active KDPG aldolases from the cyanobacterium Synechocystis and the plant barley (Hordeum vulgare) were biochemically characterized in vitro. KDPG, a metabolite unique to the ED pathway, was detected in both in vivo, indicating an active ED pathway. Phylogenetic analyses revealed that photosynthetic eukaryotes acquired KDPG aldolase from the cyanobacterial ancestors of plastids via endosymbiotic gene transfer. Several Synechocystis mutants in which key enzymes of all three glucose degradation pathways were knocked out indicate that the ED pathway is physiologically significant, especially under mixotrophic conditions (light and glucose) and under autotrophic conditions in a day/night cycle, which is probably the most common condition encountered in nature. The ED pathway has lower protein costs and ATP yields than the EMP pathway, in line with the observation that oxygenic photosynthesizers are nutrient-limited, rather than ATP-limited. Furthermore, the ED pathway does not generate futile cycles in organisms that fix CO2 via the Calvin–Benson cycle. PMID:27114545

  13. The Entner-Doudoroff pathway is an overlooked glycolytic route in cyanobacteria and plants.

    Science.gov (United States)

    Chen, Xi; Schreiber, Karoline; Appel, Jens; Makowka, Alexander; Fähnrich, Berit; Roettger, Mayo; Hajirezaei, Mohammad R; Sönnichsen, Frank D; Schönheit, Peter; Martin, William F; Gutekunst, Kirstin

    2016-05-10

    Glucose degradation pathways are central for energy and carbon metabolism throughout all domains of life. They provide ATP, NAD(P)H, and biosynthetic precursors for amino acids, nucleotides, and fatty acids. It is general knowledge that cyanobacteria and plants oxidize carbohydrates via glycolysis [the Embden-Meyerhof-Parnas (EMP) pathway] and the oxidative pentose phosphate (OPP) pathway. However, we found that both possess a third, previously overlooked pathway of glucose breakdown: the Entner-Doudoroff (ED) pathway. Its key enzyme, 2-keto-3-deoxygluconate-6-phosphate (KDPG) aldolase, is widespread in cyanobacteria, moss, fern, algae, and plants and is even more common among cyanobacteria than phosphofructokinase (PFK), the key enzyme of the EMP pathway. Active KDPG aldolases from the cyanobacterium Synechocystis and the plant barley (Hordeum vulgare) were biochemically characterized in vitro. KDPG, a metabolite unique to the ED pathway, was detected in both in vivo, indicating an active ED pathway. Phylogenetic analyses revealed that photosynthetic eukaryotes acquired KDPG aldolase from the cyanobacterial ancestors of plastids via endosymbiotic gene transfer. Several Synechocystis mutants in which key enzymes of all three glucose degradation pathways were knocked out indicate that the ED pathway is physiologically significant, especially under mixotrophic conditions (light and glucose) and under autotrophic conditions in a day/night cycle, which is probably the most common condition encountered in nature. The ED pathway has lower protein costs and ATP yields than the EMP pathway, in line with the observation that oxygenic photosynthesizers are nutrient-limited, rather than ATP-limited. Furthermore, the ED pathway does not generate futile cycles in organisms that fix CO2 via the Calvin-Benson cycle. PMID:27114545

  14. Formulation of an organic carbon trajectory over a 10-year period on a restored spoil island in south-central Florida

    Science.gov (United States)

    Schafer, T.; Ellis, R.; Osborne, T.; Hicks Pries, C.

    2015-12-01

    Long-term monitoring of restoration projects aims to determine long-term sustainability and stability of restored systems. In coastal wetlands, one indicator of restoration of ecosystem function can be seen with organic matter (specifically carbon) accretion. SL-15, a spoil island in Fort Pierce, Fl was restored in 2005, and has been monitored for return to natural condition over the last 10 years.. To assess sediment carbon accretion, sediment cores were collected in a set of eight plots, located on the SL-15 mangrove island and the surrounding seagrass recruitment area. These were analyzed for organic carbon, microbial biomass carbon, extractable carbon, and total nitrogen. The biogeochemical data collected in the previous year was compared to data collected in 2005-2007. Vegetation surveys were also completed to show the build-up of organic material in accordance with vegetation shift over the 9-year period. From this information, a trajectory has been formulated on organic carbon accretion and vegetation shift from the time of orginal restoration activities. By comparison to control sites nearby, realistic estimates of time required to reach natural levels of carbon and vegetation community structure can be calculated..

  15. Carbon-Oxygen Bond Cleavage by Bis(imino)pyridine Iron Compounds : Catalyst Deactivation Pathways and Observation of Acyl C-O Bond Cleavage in Esters

    NARCIS (Netherlands)

    Trovitch, Ryan J.; Lobkovsky, Emil; Bouwkamp, Marco W.; Chirik, Paul J.

    2008-01-01

    Investigations into the substrate scope of bis(imino)pyridine iron-catalyzed hydrogenation and [2 pi + 2 pi]. diene cyclization reactions identified C-O bond cleavage as a principal deactivation pathway. Addition of diallyl or allyl ethyl ether to the bis(imino)pyridine iron dinitrogen complex, ((iP

  16. Nitrogenases-A Tale of Carbon Atom(s).

    Science.gov (United States)

    Hu, Yilin; Ribbe, Markus W

    2016-07-11

    Named after its ability to catalyze the reduction of nitrogen to ammonia, nitrogenase has a surprising rapport with carbon-both through the interstitial carbide that resides in the central cavity of its cofactor and through its ability to catalyze the reductive carbon-carbon coupling of small carbon compounds into hydrocarbon products. Recently, a radical-SAM-dependent pathway was revealed for the insertion of carbide, which signifies a novel biosynthetic route to complex bridged metalloclusters. Moreover, a sulfur-displacement mechanism was proposed for the activation of carbon monoxide by nitrogenase, which suggests an essential role of the interstitial carbide in maintaining the stability while permitting a certain flexibility of the cofactor structure during substrate turnover. PMID:27206025

  17. 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.

  18. Estimation of biomass for calculating carbon storage and CO2 sequestration using remote sensing technology in Yok Don National Park, Central Highlands of Vietnam

    OpenAIRE

    Nguyen, Viet Luong

    2012-01-01

    Global warming and climate change are closely related to the amount of CO2 in the air. Forest ecosystem plays very important role in the global carbon cycle; CO2 from the atmosphere is taken up by vegetation and stored as plant biomass. Therefore, quantifying biomass and carbon sequestration in tropical forests has a significant concern within the United Nations Framework Convention on Climate Change (UNFCC), Kyoto Protocol and Reducing Emission from Deforestation and Forest Degradation (REDD...

  19. Design of a Geospatial Systems Model Integrating Power Generation, Transmission and Distribution for Use in Evaluating Low-Carbon Energy Pathways

    Science.gov (United States)

    Kammen, D. M.; Nelson, J.; Petros-Good, A.; Johnston, J.; Fripp, M.; Hoffman, I.; Blanco, C.

    2009-12-01

    The transition to a low-carbon economy requires the coordination of research, and implementation efforts in basic energy and systems science, energy infrastructure, and efficient, low-carbon end-use technologies, practices and polices. While the evolution of specific supply-side and end-use technologies are vital to this process, too little attention has been given to the dramatic opportunities for energy systems science, specifically the use of the transmission, storage, and distribution system, to decarbonize the energy economy. We present results from a model, Switch, that uses historic data for wind, photovoltaic and solar thermal resources and electricity loads, as well as minimum, maximum and average flows for hydroelectric facilities and detailed performance characteristics for all existing conventional generators in its region of analysis. We utilize this model to consider the potential benefits of coordinated energy supply, transmission and distribution, and end-use technology deployment and planning decisions, and to explore opportunities to minimize cost and carbon emissions over the coming decades. We present results from the Switch model for western North America under a range of carbon prices and other policy scenarios, and discuss planned expansions of the model to all of North America and China.

  20. Genetic variation in TYMS in the one-carbon transfer pathway is associated with ovarian carcinoma types in the Ovarian Cancer Association Consortium

    DEFF Research Database (Denmark)

    Kelemen, Linda E; Goodman, Marc T; McGuire, Valerie;

    2010-01-01

    We previously reported the risks of ovarian carcinoma for common polymorphisms in one-carbon transfer genes. We sought to replicate associations for DPYD rs1801265, DNMT3A rs13420827, MTHFD1 rs1950902, MTHFS rs17284990, and TYMS rs495139 with risk of ovarian carcinoma overall and to use the large...... sample of assembled cases to investigate associations by histologic type....

  1. PhnY and PhnZ comprise a new oxidative pathway for enzymatic cleavage of a carbon-phosphorus bond

    DEFF Research Database (Denmark)

    McSorley, Fern R.; Wyatt, Peter W.; Martinez, Ascuncion;

    2012-01-01

    The sequential activities of PhnY, an α-ketoglutarate/Fe(II)-dependent dioxygenase, and PhnZ, a Fe(II)-dependent enzyme of the histidine-aspartate motif hydrolase family, cleave the carbon-phosphorus bond of the organophosphonate natural product 2-aminoethylphosphonic acid. PhnY adds a hydroxyl g...

  2. Genetic variation in TYMS in the one-carbon transfer pathway is associated with ovarian carcinoma types in the Ovarian Cancer Association Consortium

    DEFF Research Database (Denmark)

    Kelemen, Linda E; Goodman, Marc T; McGuire, Valerie;

    2010-01-01

    We previously reported the risks of ovarian carcinoma for common polymorphisms in one-carbon transfer genes. We sought to replicate associations for DPYD rs1801265, DNMT3A rs13420827, MTHFD1 rs1950902, MTHFS rs17284990, and TYMS rs495139 with risk of ovarian carcinoma overall and to use the large...

  3. Validation of models using Chernobyl fallout data from the Central Bohemia region of the Czech Republic. Scenario CB. First report of the VAMP Multiple Pathways Assessment Working Group. Part of the IAEA/CEC Co-ordinated Research Programme on the Validation of Environmental Model Predictions (VAMP)

    International Nuclear Information System (INIS)

    The VAMP Multiple Pathways Assessment Working Group is an international forum for the testing and comparison of model predictions. The emphasis is on evaluating transfer from the environment to human via all pathways which are relevant in the environment being considered. This document is the first report of the Group and contains the results of the first test exercise on the validation of multiple pathways assessment models using Chernobyl fallout data obtained from the Central Bohemia (CB) region of the Czech Republic (Scenario CB). The report includes the following three appendixes: Documentation and evaluation of model validation data used in scenario CB (3 papers), Description of models used in scenario CB (1 paper), Individual evaluations of model predictions for scenario CB (13 papers). A separate abstract was prepared for each paper. Refs, figs and tabs

  4. Pathways of carbon oxidation in an Arctic fjord sediment (Svalbard) and isolation of psychrophilic and psychrotolerant Fe(III)-reducing bacteria

    DEFF Research Database (Denmark)

    Vandieken, Verona; Finke, Niko; Jørgensen, Bo Barker

    2006-01-01

    reduction was the most important anaerobic mineralization process, accounting for 57 % of anaerobic organic carbon oxidation in anoxic bag incubations of the top 5 cm of the sediment. The remaining 43 % oxidation was attributed to microbial Fe(III) reduction. Both processes occurred concurrently...... to total carbon oxidation: aerobic respiration 53 %, sulfate reduction 34 %, Fe(III) reduction 13 %. In situ, the importance of Fe(III) reduction may vary through competition for substrate with oxygen- and nitrate-reducing bacteria in the surface sediment. Fe (111)-reducing bacteria belonging to the genera...... point of sea water, indicating adaptation to permanently cold temperatures. Besides Fe(III), the strains reduced other electron acceptors such as oxygen, manganese, elemental sulfur and sulfate....

  5. Biosynthesis of monoterpenoids in higher plants. The biosynthetic pathway leading to the monoterpenoids from amino acids with a carbon-skeleton similar to mevalonic acid

    Energy Technology Data Exchange (ETDEWEB)

    Tange, K. (Hiroshima Univ. (Japan). Faculty of Science)

    1981-09-01

    Radioisotopically labeled L-valine, DL-alanine, sodium acetate, and DL-mevalonic acid were incorporated into linalool by the intact plant of Cinnamomum camphora Sieb. var. linalooliferum Fujita and into geraniol and citronellol by that of Pelargonium roseum Bourbon. The uptake of leucine and valine resulted in the preferential location of the radioactivity on the 3,3-dimethylallyl pyrophosphate-derived moiety of these acyclic monoterpenoids, whereas the uptake of alanine resulted in the preferential location on the isopentenyl pyrophosphate-derived moiety, much as in the cases of mevalonic acid and sodium acetate. A biosynthetic pathway leading to the monoterpenoids from the amino acids is discussed.

  6. Using a Regional Cluster of AmeriFlux Sites in Central California to Advance Our Knowledge on Decadal-Scale Ecosystem-Atmosphere Carbon Dioxide Exchange

    Energy Technology Data Exchange (ETDEWEB)

    Baldocchi, Dennis [Univ. of California, Berkeley, CA (United States)

    2015-03-24

    Continuous eddy convariance measurements of carbon dioxide, water vapor and heat were measured continuously between an oak savanna and an annual grassland in California over a 4 year period. These systems serve as representative sites for biomes in Mediterranean climates and experience much seasonal and inter-annual variability in temperature and precipitation. These sites hence serve as natural laboratories for how whole ecosystem will respond to warmer and drier conditions. The savanna proved to be a moderate sink of carbon, taking up about 150 gC m-2y-1 compared to the annual grassland, which tended to be carbon neutral and often a source during drier years. But this carbon sink by the savanna came at a cost. This ecosystem used about 100 mm more water per year than the grassland. And because the savanna was darker and rougher its air temperature was about 0.5 C warmer. In addition to our flux measurements, we collected vast amounts of ancillary data to interpret the site and fluxes, making this site a key site for model validation and parameterization. Datasets consist of terrestrial and airborne lidar for determining canopy structure, ground penetrating radar data on root distribution, phenology cameras monitoring leaf area index and its seasonality, predawn water potential, soil moisture, stem diameter and physiological capacity of photosynthesis.

  7. Evaluation of carbon stocks in above- and below-ground biomass in Central Africa: case study of Lesio-louna tropical rainforest of Congo

    Science.gov (United States)

    Liu, X.; Ekoungoulou, R.; Loumeto, J. J.; Ifo, S. A.; Bocko, Y. E.; Koula, F. E.

    2014-07-01

    The study was aimed to estimate the carbon stocks of above- and below-ground biomass in Lesio-louna forest of Congo. The methodology of allometric equations was used to measure the carbon stocks of Lesio-louna natural forest. We are based precisely on the model II which is also called non-destructive method or indirect method of measuring carbon stocks. While there has been use of parameters such as the DBH and wood density. The research was done with 22 circular plots each 1256 m2. In the 22 plots studied, 19 plots are in the gallery forest and three plots in the secondary forest. Also, 22 circular plots were distributed in 5 sites studies of Lesio-louna forest, including: Inkou forest island, Iboubikro, Ngoyili, Blue lake and Ngambali. So, there are two forest types (secondary forest and gallery forest) in this forest ecosystem. In the 5 sites studied, we made measurements on a total of 347 trees with 197 trees for the class of 10-30 cm diameter, 131 trees for the class of 30-60 cm diameter and 19 trees in the diameter class > 60 cm. The results show that in the whole forest, average carbon stock for the 22 plots of the study was 168.601 t C ha-1 for AGB, or 81% and 39.551 t C ha-1 for BGB, or 19%. The total carbon stocks in all the biomass was 3395.365 t C for AGB, which is 3.395365 × 10-6 Gt C and 909.689934 t C for BGB, which was 9.09689934 × 10-7 Gt C. In this forest, the carbon stock was more important in AGB compared to BGB with respectively 3395.365 t C against 909.689934 t C. Plot10 (AGB = 363.899 t C ha-1 and BGB = 85.516 t C ha-1) was the most dominant in terms of carbon quantification in Lesio-louna.

  8. Evaluation of carbon stocks in above- and below-ground biomass in Central Africa: case study of Lesio-louna tropical rainforest of Congo

    Directory of Open Access Journals (Sweden)

    X. Liu

    2014-07-01

    Full Text Available The study was aimed to estimate the carbon stocks of above- and below-ground biomass in Lesio-louna forest of Congo. The methodology of allometric equations was used to measure the carbon stocks of Lesio-louna natural forest. We are based precisely on the model II which is also called non-destructive method or indirect method of measuring carbon stocks. While there has been use of parameters such as the DBH and wood density. The research was done with 22 circular plots each 1256 m2. In the 22 plots studied, 19 plots are in the gallery forest and three plots in the secondary forest. Also, 22 circular plots were distributed in 5 sites studies of Lesio-louna forest, including: Inkou forest island, Iboubikro, Ngoyili, Blue lake and Ngambali. So, there are two forest types (secondary forest and gallery forest in this forest ecosystem. In the 5 sites studied, we made measurements on a total of 347 trees with 197 trees for the class of 10–30 cm diameter, 131 trees for the class of 30–60 cm diameter and 19 trees in the diameter class > 60 cm. The results show that in the whole forest, average carbon stock for the 22 plots of the study was 168.601 t C ha−1 for AGB, or 81% and 39.551 t C ha−1 for BGB, or 19%. The total carbon stocks in all the biomass was 3395.365 t C for AGB, which is 3.395365 × 10–6 Gt C and 909.689934 t C for BGB, which was 9.09689934 × 10–7 Gt C. In this forest, the carbon stock was more important in AGB compared to BGB with respectively 3395.365 t C against 909.689934 t C. Plot10 (AGB = 363.899 t C ha−1 and BGB = 85.516 t C ha−1 was the most dominant in terms of carbon quantification in Lesio-louna.

  9. The effects of land use change on carbon content in the aerial biomass of an Abies religiosa (Kunth Schltdl. et Cham. forest in central Veracruz, Mexico

    Directory of Open Access Journals (Sweden)

    M.R. Pineda Lopez

    2013-04-01

    Full Text Available Aim of study. Were analyzed patterns and dynamics of forest cover change and land use for the period 1995-2005, and estimated carbon content in biomass in a forest of fir (Abies religiosa.Area of study. Ejido El Conejo in the Cofre de Perote National Park, Veracruz, Mexico.Material and Methods. Spatial data (maps, orthophotographs were used: (UTM; GRS 80 spheroid; zone 14, datum ITRF92; units: metres. Maps for 1995 and 2005 were constructed and compared. Carbon content in the aboveground biomass of fir (Abies religiosa was estimated using an equation specific to species.Main results. After one decade, the forested area had increased slightly (0.25%. The main type of land cover change was from shrubland to forest (probability of change 0.41; the change from forestland to shrubland with trees was 0.05%, and from forest to agriculture was 0.02%. Data from 2008 confirmed that the A. religiosa forest located in the ejido is distributed in largely unconnected fragments, of which some have a high density of young trees. Estimated carbon content in the aboveground biomass (163.51 Mg ha-1 was higher than that estimated for other forests of the same species in Mexico.Research highlights. It is recommended that ecological corridors be established throughout the reforested area, in order to connect these fragments (and increase carbon sequestration and favour faunal and floral conservation. Finally, recognition should be given to the high vulnerability of A. religiosa forests to climate change, given their high degree of fragmentation and critical altitudinal limit.Key words: Aboveground biomass; carbon storage; ecological corridors; fir forest.

  10. Manipulation of carbon flux into fatty acid biosynthesis pathway in Dunaliella salina using AccD and ME genes to enhance lipid content and to improve produced biodiesel quality

    Directory of Open Access Journals (Sweden)

    Ahmad Farhad Talebi

    2014-08-01

    Full Text Available Advanced generations of biofuels basically revolve around non-agricultural energy crops. Among those, microalgae owing to its unique characteristics i.e. natural tolerance to waste and saline water, sustainable biomass production and high lipid content (LC, is regarded by many as the ultimate choice for the production of various biofuels such as biodiesel. In the present study, manipulation of carbon flux into fatty acid biosynthesis pathway in Dunaliella salina was achieved using pGH plasmid harboring AccD and ME genes to enhance lipid content and to improve produced biodiesel quality. The stability of transformation was confirmed by PCR after several passages. Southern hybridization of AccD probe with genomic DNA revealed stable integration of the cassette in the specific positions in the chloroplast genome with no read through transcription by indigenous promoters. Comparison of the LC and fatty acid profile of the transformed algal cell line and the control revealed the over-expression of the ME/AccD genes in the transformants leading to 12% increase in total LC and significant improvements in biodiesel properties especially by increasing algal oil oxidation stability. The whole process successfully implemented herein for transforming algal cells by genes involved in lipid production pathway could be helpful for large scale biodiesel production from microalgae.

  11. The CCAAT box-binding factor stimulates ammonium assimilation in Saccharomyces cerevisiae, defining a new cross-pathway regulation between nitrogen and carbon metabolisms.

    OpenAIRE

    Dang, V D; Bohn, C.; Bolotin-Fukuhara, M.; Daignan-Fornier, B

    1996-01-01

    In Saccharomyces cerevisiae, carbon and nitrogen metabolisms are connected via the incorporation of ammonia into glutamate; this reaction is catalyzed by the NADP-dependent glutamate dehydrogenase (NADP-GDH) encoded by the GDH1 gene. In this report, we show that the GDH1 gene requires the CCAAT box-binding activator (HAP complex) for optimal expression. This conclusion is based on several lines of evidence: (1) overexpression of GDH1 can correct the growth defect of hap2 and hap3 mutants on a...

  12. Degradation of endogenous hepatic heme by pathways not yielding carbon monoxide. Studies in normal rat liver and in primary hepatocyte culture.

    OpenAIRE

    Bissell, D. M.; Guzelian, P S

    1980-01-01

    The conversion of endogenous hepatic heme to bilirubin and CO is established. However, it is unknown whether this process is quantitative or whether heme may be degraded to other products as well. To study this question, we administered the heme precursor, delta-amino-[5-14C]levulinic acid to rats in vivo. In liver, [14C]heme was predominately associated with microsomal cytochromes, and its degradation was examined over a period of 12--14 h; concurrently, excretion of labeled carbon monoxide ...

  13. Colloquium on Central Asia

    International Nuclear Information System (INIS)

    This colloquium on Azerbaijan was organized by the direction of international relations of the French Senate and the French center of foreign trade (CFCE). This document gathers the interventions of the participants and the debates with the audience following these interventions. The topics treated concern: - the present day political-economical situation of Central Asia countries (problem of borders, relations with Russia and China); - the economies of Central Asia countries: short term problems and medium-term perspectives; - the relations with the European Union (political, economical, trade and investments, perspectives); - the European energy stakes of Caspian sea (oil and gas reserves, development of hydrocarbon resources, exploitation and transport constraints, stakes for Europe and France); - TotalFinaElf company in Central Asia (Kazakhstan, Azerbaijan, enclavement problem); - the economical impacts of the TRACECA pathway (Transport Corridor Europe Caucasus Asia). (J.S.)

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

    Science.gov (United States)

    Yu, Jian; Si, Yingtao

    2004-01-01

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

  15. Molecular pathways

    DEFF Research Database (Denmark)

    Cox, Thomas R; Erler, Janine Terra

    2014-01-01

    45% of deaths in the developed world are linked to fibrotic disease. Fibrosis and cancer are known to be inextricably linked; however, we are only just beginning to understand the common and overlapping molecular pathways between the two. Here, we discuss what is known about the intersection of...... fibrosis and cancer, with a focus on cancer metastasis, and highlight some of the exciting new potential clinical targets that are emerging from analysis of the molecular pathways associated with these two devastating diseases. Clin Cancer Res; 20(14); 3637-43. ©2014 AACR....

  16. The effects of land use change on carbon content in the aerial biomass of an Abies religiosa (Kunth Schltdl. et Cham.) forest in central Veracruz, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Pineda-Lopez, M. R.; Sanchez-Velasquez, L. R.; Vazquez-Dominguez, G.; Rojo-Alboreca, A.

    2013-05-01

    Aim of study.) Were analyzed patterns and dynamics of forest cover change and land use for the period 1995-2005, and estimated carbon content in biomass in a forest of fir (Abies religiosa). Area of study. Ejido El Conejo in the Cofre de Perote National Park, Veracruz, Mexico. Material and Methods. Spatial data (maps, ortho photographs) were used: (UTM); GRS 80 spheroid; zone 14, datum ITRF92; units: metres. Maps for 1995 and 2005 were constructed and compared. Carbon content in the aboveground biomass of fir (Abies religiosa) was estimated using an equation specific to species. Main results. After one decade, the forested area had increased slightly (0.25%). The main type of land cover change was from shrubland to forest (probability of change 0.41); the change from forestland to shrubland with trees was 0.05%, and from forest to agriculture was 0.02%. Data from 2008 confirmed that the A. religiosa forest located in the ejido is distributed in largely unconnected fragments, of which some have a high density of young trees. Estimated carbon content in the aboveground biomass (163.51 Mg ha-1) was higher than that estimated for other forests of the same species in Mexico. Research highlights. It is recommended that ecological corridors be established throughout the reforested area, in order to connect these fragments (and increase carbon sequestration) and favour faunal and floral conservation. Finally, recognition should be given to the high vulnerability of A. religiosa forests to climate change, given their high degree of fragmentation and critical altitudinal limit. (Author) 55 refs.

  17. Biochar production for carbon sequestration

    Energy Technology Data Exchange (ETDEWEB)

    Thakkar, J.; Kumar, A. [Alberta Univ., Edmonton, AB (Canada). Dept. of Mechanical Engineering

    2010-07-01

    This study examined the use of agricultural biomass for biochar production and its storage in a landfill to sequester carbon. Capturing the energy from biomass that would otherwise decay, is among the many options available to mitigate the impact of the greenhouse gas (GHG) emissions associated with fossil fuel consumption. Biochar is a solid fuel which can be produced from agricultural biomass such as wheat and barley straw. This organic solid can be produced by slow pyrolysis of straw. A conceptual techno-economic model based on actual data was used to estimate the cost of producing biochar from straw in a centralized plant. The objectives of the study were to estimate the overall delivered cost of straw to the charcoal production plant; estimate the transportation costs of charcoal to the landfill site; estimate the cost of landfill; and estimate the overall cost of carbon sequestration through a charcoal landfill. According to preliminary results, the cost of carbon sequestration through this pathway is greater than $50 per tonne of carbon dioxide.

  18. Nano-risk Science: application of toxicogenomics in an adverse outcome pathway framework for risk assessment of multi-walled carbon nanotubes

    DEFF Research Database (Denmark)

    Labib, Sarah; Williams, Andrew; Yauk, Carole L.;

    2016-01-01

    Background: A diverse class of engineered nanomaterials (ENMs) exhibiting a wide array of physical-chemical properties that are associated with toxicological effects in experimental animals is in commercial use. However, an integrated framework for human health risk assessment (HHRA) of ENMs has...... yet to be established. Rodent 2-year cancer bioassays, clinical chemistry, and histopathological endpoints are still considered the 'gold standard' for detecting substance-induced toxicity in animal models. However, the use of data derived from alternative toxicological tools, such as genome......-based points of departure (PODs) for multi-walled carbon nanotube (MWCNT)-induced lung fibrosis, a non-cancer endpoint of regulatory importance. Methods: Gene expression profiles from the lungs of mice exposed to three individual MWCNTs with different physical-chemical properties were used within the framework...

  19. Pathways of carbon oxidation in an Arctic fjord sediment (Svalbard) and isolation of psychrophilic and psychrotolerant Fe(III)-reducing bacteria

    DEFF Research Database (Denmark)

    Vandieken, Verona; Finke, Niko; Jørgensen, Bo Barker

    2006-01-01

    was the most important anaerobic mineralization process, accounting for 57% of anaerobic organic carbon oxidation in anoxic bag incubations of the top 5 cm of the sediment. The remaining 43% oxidation was attributed to microbial Fe(III) reduction. Both processes occurred concurrently in the uppermost 2 cm...... oxidation: aerobic respiration 53%, sulfate reduction 34%, Fe(III) reduction 13%. In situ, the importance of Fe(III) reduction may vary through competition for substrate with oxygen- and nitrate-reducing bacteria in the surface sediment. Fe(III)-reducing bacteria belonging to the genera Desulfuromonas......, indicating adaptation to permanently cold temperatures. Besides Fe(III), the strains reduced other electron acceptors such as oxygen, manganese, elemental sulfur and sulfate....

  20. Carbon and hydrogen isotopic evidence for the origin of combustible gases in water-supply wells in north-central Pennsylvania

    Science.gov (United States)

    Révész, K. M.; Breen, K.J.; Baldassare, A.J.; Burruss, R.C.

    2010-01-01

    The origin of the combustible gases in groundwater from glacial-outwash and fractured-bedrock aquifers was investigated in northern Tioga County, Pennsylvania. Thermogenic methane (CH4) and ethane (C2H6) and microbial CH4 were found. Microbial CH4 is from natural in situ processes in the shale bedrock and occurs chiefly in the bedrock aquifer. The δ13C values of CH4 and C2H6 for the majority of thermogenic gases from water wells either matched or were between values for the samples of non-native storage-field gas from injection wells and the samples of gas from storage-field observation wells. Traces of C2H6 with microbial CH4 and a range of C and H isotopic compositions of CH4 indicate gases of different origins are mixing in sub-surface pathways; gas mixtures are present in groundwater. Pathways for gas migration and a specific source of the gases were not identified. Processes responsible for the presence of microbial gases in groundwater could be elucidated with further geochemical study.

  1. 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...

  2. A metabolomic study in oats (Avena sativa) highlights a drought tolerance mechanism based upon salicylate signalling pathways and the modulation of carbon, antioxidant and photo-oxidative metabolism.

    Science.gov (United States)

    Sánchez-Martín, Javier; Heald, Jim; Kingston-Smith, Alison; Winters, Ana; Rubiales, Diego; Sanz, Mariluz; Mur, Luis A J; Prats, Elena

    2015-07-01

    Although a wealth of information is available on the induction of one or several drought-related responses in different species, little is known of how their timing, modulation and crucially integration influence drought tolerance. Based upon metabolomic changes in oat (Avena sativa L.), we have defined key processes involved in drought tolerance. During a time course of increasing water deficit, metabolites from leaf samples were profiled using direct infusion-electrospray mass spectroscopy (DI-ESI-MS) and high-performance liquid chromatography (HPLC) ESI-MS/MS and analysed using principal component analysis (PCA) and discriminant function analysis (DFA). The involvement of metabolite pathways was confirmed through targeted assays of key metabolites and physiological experiments. We demonstrate an early accumulation of salicylic acid (SA) influencing stomatal opening, photorespiration and antioxidant defences before any change in the relative water content. These changes are likely to maintain plant water status, with any photoinhibitory effect being counteracted by an efficient antioxidant capacity, thereby representing an integrated mechanism of drought tolerance in oats. We also discuss these changes in relation to those engaged at later points, consequence of the different water status in susceptible and resistant genotypes.

  3. Chemical processes of coal for use in power plants. Part 1: Approximate analysis and associated indexes of pulverized coal; Procesos quimicos del carbon para su uso en centrales termoelectricas. Parte 1: Analisis aproximado e indices asociados del carbon pulverizado

    Energy Technology Data Exchange (ETDEWEB)

    Altamirano-Bedolla, J. A.; Manzanares-Papayanopoulos, E.; Herrera-Velarde, J. R. [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)]. E-mail: emp@iie.org.mx

    2010-11-15

    The usage of hydrocarbons, such as natural gas, oil products and coal, will be the main source of energy to the mankind for next generations. Therefore, the actual research and technological developments point out to employ with high efficiency those fuels. The main interests are to release most of the energy as possible and to guide the combustion reactions. It is well known that during the combustion process of coal, the chemical energy is converted to thermal energy, which it allows the steam production, and therefore to produce energy through an electric generator. The main interest of the work presented here is to study the behavior of the coal combustion processes in function of the approximate analysis and some associate indices of that analysis, to point out the optimization of the coal usage as main fuel in electrical power generation plants. [Spanish] El uso de hidrocarburos como son el gas natural, los derivados del petroleo y el carbon mineral, continuara siendo en las proximas decadas la principal fuente de energia de la humanidad. Por consiguiente, la investigacion cientifica y los desarrollos tecnologicos actualmente se enfocan en emplear de manera mas eficiente dichos combustibles, satisfaciendo entre otros factores, dos intereses principales: liberar la mayor cantidad de energia, reduciendo al minimo el material combustible no quemado, y direccionar las reacciones del proceso de combustion para minimizar la cantidad de productos no deseados resultantes de la reaccion. A traves de los procesos quimicos de combustion del carbon, se transforma la energia quimica a energia termica, lo que permite la produccion de vapor para a su vez impulsar una turbina la cual esta acoplada a un generador electrico. El objetivo del presente trabajo es el estudio del comportamiento de los procesos quimicos que se llevan a cabo durante las reacciones de combus-tion del carbon en funcion del analisis aproximado y de los indices asociados resultantes de dicho analisis; lo

  4. 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.

  5. Distribution and phylogenies of enzymes of the Embden-Meyerhof-Parnas pathway from archaea and hyperthermophilic bacteria support a gluconeogenic origin of metabolism

    Directory of Open Access Journals (Sweden)

    Ron S. Ronimus

    2003-01-01

    Full Text Available Enzymes of the gluconeogenic/glycolytic pathway (the Embden-Meyerhof-Parnas (EMP pathway, the reductive tricarboxylic acid cycle, the reductive pentose phosphate cycle and the Entner-Doudoroff pathway are widely distributed and are often considered to be central to the origins of metabolism. In particular, several enzymes of the lower portion of the EMP pathway (the so-called trunk pathway, including triosephosphate isomerase (TPI; EC 5.3.1.1, glyceraldehyde-3-phosphate dehydrogenase (GAPDH; EC 1.2.1.12/13, phosphoglycerate kinase (PGK; EC 2.7.2.3 and enolase (EC 4.2.1.11, are extremely well conserved and universally distributed among the three domains of life. In this paper, the distribution of enzymes of gluconeogenesis/glycolysis in hyperthermophiles—microorganisms that many believe represent the least evolved organisms on the planet—is reviewed. In addition, the phylogenies of the trunk pathway enzymes (TPIs, GAPDHs, PGKs and enolases are examined. The enzymes catalyzing each of the six-carbon transformations in the upper portion of the EMP pathway, with the possible exception of aldolase, are all derived from multiple gene sequence families. In contrast, single sequence families can account for the archaeal and hyperthermophilic bacterial enzyme activities of the lower portion of the EMP pathway. The universal distribution of the trunk pathway enzymes, in combination with their phylogenies, supports the notion that the EMP pathway evolved in the direction of gluconeogenesis, i.e., from the bottom up.

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

    Science.gov (United States)

    Nilsson, Roland; Jain, Mohit

    2016-05-24

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

  7. Mantle helium and carbon isotopes in Separation Creek Geothermal Springs, Three Sisters area, Central Oregon: Evidence for renewed volcanic activity or a long term steady state system?

    Energy Technology Data Exchange (ETDEWEB)

    van Soest, M.C.; Kennedy, B.M.; Evans, W.C.; Mariner, R.H.

    2002-04-30

    Cold bubbling springs in the Separation Creek area, the locus of current uplift at South Sister volcano show strong mantle signatures in helium and carbon isotopes and CO{sub 2}/{sup 3}He. This suggests the presence of fresh basaltic magma in the volcanic plumbing system. Currently there is no evidence to link this system directly to the uplift, which started in 1998. To the contrary, all geochemical evidence suggests that there is a long-lived geothermal system in the Separation Creek area, which has not significantly changed since the early 1990s. There was no archived helium and carbon data, so a definite conclusion regarding the strong mantle signature observed in these tracers cannot yet be drawn. There is a distinct discrepancy between the yearly magma supply required to explain the current uplift (0.006 km{sup 3}/yr) and that required to explain the discharge of CO{sub 2} from the system (0.0005 km{sup 3}/yr). This discrepancy may imply that the chemical signal associated with the increase in magma supply has not reached the surface yet. With respect to this the small changes observed at upper Mesa Creek require further attention, due to the recent volcanic vent in that area it may be the location were the chemical signal related to the uplift can most quickly reach the surface. Occurrence of such strong mantle signals in cold/diffuse geothermal systems suggests that these systems should not be ignored during volcano monitoring or geothermal evaluation studies. Although the surface-expression of these springs in terms of heat is minimal, the chemistry carries important information concerning the size and nature of the underlying high-temperature system and any changes taking place in it.

  8. Reservoir Characterization for CO2 Sequestration: Assessing the Potential of the Devonian Carbonate Nisku Formation of Central Alberta Caractérisation de réservoir en vue du stockage géologique de CO2 : évaluation du potentiel offert par les carbonates dévoniens de la formation de Nisku, en Alberta central

    Directory of Open Access Journals (Sweden)

    Eisinger C.

    2011-02-01

    Full Text Available The Wabamun Lake area of Central Alberta, Canada includes several large CO2 point source emitters, collectively producing more than 30 Mt annually. Previous studies established that deep saline aquifers beneath the Wabamun Lake area have good potential for the large-scale injection and storage of CO2. This study reports on the characterization of the Devonian carbonate Nisku Formation for evaluation as a CO2 repository. Major challenges for characterization included sparse well and seismic data, poor quality flow tests, and few modern measurements. Wireline porosity measurements were present in only one-third of the wells, so porosity and flow capacity (permeability-thickness were estimated using wireline electrical measurements. The Archie cementation factor appears to vary between 2 and 3, creating uncertainty when predicting porosity using the electrical measurements; however, high-porosity zones could be identified. The electrically-based flow capacity predictions showed more favorable values using a correlation with core than the relation based on drill stem and production tests. This behavior is expected, since the flow test flow capacities are less influenced by local occurrences of very permeable vuggy and moldic rocks. Facies distributions were modeled using both pixel and object methods. The object models, using dimensions obtained from satellite imaging of modern day environments, gave results that were more consistent with the geological understanding of the Nisku and showed greater large-scale connectivity than the pixel model. Predicted volumes show considerable storage capacity in the Nisku, but flow simulations suggest injection capacities are below an initial 20 Mt/year target using vertical wells. More elaborate well designs, including fracture stimulation or multi-lateral wells may allow this goal to be reached or surpassed. Plusieurs gros émetteurs de CO2, totalisant 30 Mt annuels, sont localisés dans la région du Lac

  9. Clinical analysis and treatment of central pain due to headinjury

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    @@Central pain is induced by the involvement of the abnormal pain pathway due to diseases of the central nervous system. Central pain after brain trauma is common clinically, but it is often misdiagnosed and neglected because of lack of objective disturbances. We treated 20 cases of central pain after head injury by invigorating blood circulation and satisfactory result was obtained.

  10. Central control of body temperature.

    Science.gov (United States)

    Morrison, Shaun F

    2016-01-01

    Central neural circuits orchestrate the behavioral and autonomic repertoire that maintains body temperature during environmental temperature challenges and alters body temperature during the inflammatory response and behavioral states and in response to declining energy homeostasis. This review summarizes the central nervous system circuit mechanisms controlling the principal thermoeffectors for body temperature regulation: cutaneous vasoconstriction regulating heat loss and shivering and brown adipose tissue for thermogenesis. The activation of these thermoeffectors is regulated by parallel but distinct efferent pathways within the central nervous system that share a common peripheral thermal sensory input. The model for the neural circuit mechanism underlying central thermoregulatory control provides a useful platform for further understanding of the functional organization of central thermoregulation, for elucidating the hypothalamic circuitry and neurotransmitters involved in body temperature regulation, and for the discovery of novel therapeutic approaches to modulating body temperature and energy homeostasis. PMID:27239289

  11. The Protective Effects of the Supercritical-Carbon Dioxide Fluid Extract of Chrysanthemum indicum against Lipopolysaccharide-Induced Acute Lung Injury in Mice via Modulating Toll-Like Receptor 4 Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Xiao-Li Wu

    2014-01-01

    Full Text Available The supercritical-carbon dioxide fluid extract of Chrysanthemum indicum Linné. (CFE has been demonstrated to be effective in suppressing inflammation. The aim of this study is to investigate the preventive action and underlying mechanisms of CFE on acute lung injury (ALI induced by lipopolysaccharide (LPS in mice. ALI was induced by intratracheal instillation of LPS into lung, and dexamethasone was used as a positive control. Results revealed that pretreatment with CFE abated LPS-induced lung histopathologic changes, reduced the wet/dry ratio and proinflammatory cytokines productions (TNF-α, IL-1β, and IL-6, inhibited inflammatory cells migrations and protein leakages, suppressed the levels of MPO and MDA, and upregulated the abilities of antioxidative enzymes (SOD, CAT, and GPx. Furthermore, the pretreatment with CFE downregulated the activations of NF-κB and the expressions of TLR4/MyD88. These results suggested that CFE exerted potential protective effects against LPS-induced ALI in mice and was a potential therapeutic drug for ALI. Its mechanisms were at least partially associated with the modulations of TLR4 signaling pathways.

  12. Dissecting the Role of Hedgehog Pathway in Murine Gonadal Development

    Science.gov (United States)

    Barsoum, Ivraym Boshra

    2009-01-01

    Hedgehog (Hh) signaling pathway is one of the universal pathways involved in animal development. This dissertation focuses on Hh role in the mammalian gonad development, which is a central part of mammalian sexual development and identity. The central dogma of mammalian sex development is that genetic sex determines the gonadal sex, which in turn…

  13. Eustatic and far-field tectonic control on the development of an intra-platform carbonate-shoal complex: upper tongue of the Tanglewood Member, Upper Ordovician Lexington Limestone, central Kentucky, U.S.A.

    Science.gov (United States)

    Koirala, Dibya Raj; Ettensohn, Frank R.; Clepper, Marta L.

    2016-11-01

    The Lexington or Trenton Limestone is an Upper Ordovician (Chatfieldian-Edenian; upper Sandbian-lower Katian), temperate-water unit, averaging about 60-m thick, that was deposited in relatively shallow waters across the Lexington Platform in east-central United States during the Taconian Orogeny. Lexington/Trenton shallow-water deposition ended across most of the platform in late Chatfieldian time and from that point deepened upward into the more shale-rich Clays Ferry, Point Pleasant and Kope formations due to apparent sea-level rise. In central Kentucky, however, deposition of the Lexington Limestone continued into early Edenian time and includes up to 50 m of additional coarse calcarenites and calcirudites at the top, which form the Tanglewood buildup and reflect locally regressive conditions, apparently related to local structural uplift. Consequently, in central Kentucky, the Lexington is more than 100-m thick, and Lexington deposition on the buildup continued into early Edenian time as an intra-platform shoal complex that tongues out into deeper-water units in all directions. In an attempt to understand how this shoal complex developed, we examined the last major body of coarse skeletal sands in the central Kentucky Lexington Limestone, the upper tongue of the Tanglewood Member, a 12-m-thick succession of fossiliferous calcarenite and calcirudite that occurs across an area of 5200 km2 near the center of the Lexington Platform. Although relatively homogeneous, the upper Tanglewood is divisible into five, small-scale, fining-upward, sequence-like cycles, which contain prominent, widespread deformed horizons. Facies analysis indicates that four lithofacies, which reflect distinct depositional environments, comprise the sequences across the shoal complex. Lithofacies were correlated across the shoal complex by integrating cyclicity and widespread deformed horizons in order to delineate the locations of major depositional environments. Facies analysis shows that

  14. 碳交易与碳税兼容性分析--兼论中国减排路径选择%Study on the Pathway of China to Mitigate Emissions Based on the Compatibility of Carbon Tax and ETS

    Institute of Scientific and Technical Information of China (English)

    魏庆坡

    2015-01-01

    As important environmental policy instruments, ETS and carbon tax are dedicated to address climate change and promote low carbon economy. However, none of them could achieve the theoretical emission reduction results. With the increasingly serious climate problem and emission mitigation presaue, more and more countries are trying to employ more than one environmental policy instrument to tackle carbon emission issues, including China. But the realistic problems are whether these two ‘quite different ’ emission reduction systems could work well and how they can work well. On the basis of theory analysis, this paper discussed the compatibility between absolute emission reduction target and carbon tax, and the result shows that there are systematic problems. As to relative emission reduction target, the result shows that it could be compatible with carbon tax. For the issues related to absolute target, this thesis argued that ceiling price and floor price, banking system, borrowing system, reducing the overlap of adjustment coverage, projects offsetting and other systems should be introduced, which could improve the defects of both in reality and constitute a hybrid system with enhancing both advantages and avoiding their disadvantages. With background of establishing national ETS market and preparation of carbon tax, taking the compatibility analysis above as a basis, proceeding from China ’ s reduction commitment and domestic pilot ETSs, we argued that China, as a developing country, should consider the social economy development as the prerequisite of emission mitigation. Responding to initial period of mitigation and arduous reduction task, as well as low-volume transaction having little impact on allowance price fluctuation, this paper put forward that incorporating carbon tax to address environmental complexity and diversity. Furthermore, these instrument combinations could increase taxes revenues, balance mitigation pressure, etc. Therefore, the pathway

  15. Origin and pathways of pro- and retrograde fluids, PTt paths and fluid-mineral equilibria from Alpine veins of the Central Alps : case studies of the Fibbia and Amsteg areas

    OpenAIRE

    Heijboer, Tjerk Cornelis

    2006-01-01

    In order to constrain the conditions of and processes related to vein formation and the origins of mineralising fluids, field work, multiple geochemical methods applied to whole rocks, minerals, and fluid inclusions, as well as thermodynamic modeling on these veinwall rock systems have been carried out. The focus of this study was on vein and fissure systems from two particular areas in the external parts of the Central Alps: the Fibbia area in the southern Gotthard massif and ...

  16. Impact of Predicted Changes in Rainfall and Atmospheric Carbon Dioxide on Maize and Wheat Yields in the Central Rift Valley of Ethiopia

    Science.gov (United States)

    Muluneh, A.; Biazin, B.; Stroosnijder, L.; Bewket, W.; Keesstra, S.

    2014-12-01

    The objective of this study was to assess potential impacts of climate change on maize and wheat yields in the Central Rift Valley of Ethiopia. We considered effects of elevated atmospheric CO2 and changes in rainfall during the main (Kiremt) and the short (Belg) rain and cropping seasons. Crop yield simulations were made with the FAO AquaCrop model using baseline climate data and climate change scenarios projected by the ECHAM5 General Circulation Model under A2 (high) and B1 (low) emission scenarios. The MarkSimGCM daily weather generator was used to generate projected daily values of precipitation and temperature. The projected rainfall during Kiremt shows an increase by about 12-69% while projected Belg rainfall decreases by up to 68%. The mean onset of the Belg cropping season for maize is projected to be delayed by 2-9 weeks and the mean cessation is expected to be extended by more than a month in sub-humid/humid areas of the CRV. In most of the sub-humid/humid areas, the 90 day maize and wheat growing periods will not have dry spells lasting longer than 10 consecutive days. However, in the semiarid areas dry spells could last longer than 15 days. The mean simulated maize yield increased by up to 30% due to changes in the projected seasonal rainfall alone, and by up to 14% due to elevated CO2 alone. The combined effect of elevated CO2 and projected climate factors increased maize yields by up to 59% in sub-humid/humid areas, but resulted in a decrease of up to 46% in the semiarid areas. Wheat yield showed no significant response to the projected rainfall changes, but increased by up to 40% due to elevated CO2. Our results suggest that climate change will increase crop yields in the sub humid/humid regions of the CRV. However, in semi-arid areas the overall projected climate change will affect the yield negatively.

  17. Paleogene biomarker records from the central Arctic Ocean (Integrated Ocean Drilling Program Expedition 302): Organic carbon sources, anoxia, and sea surface temperature

    Science.gov (United States)

    Weller, Petra; Stein, Ruediger

    2008-03-01

    During Integrated Ocean Drilling Program Expedition 302 (Arctic Coring Expedition (ACEX)) a more than 200 m thick sequence of Paleogene organic carbon (OC)-rich (black shale type) sediments was drilled. Here we present new biomarker data determined in ACEX sediment samples to decipher processes controlling OC accumulation and their paleoenvironmental significance during periods of Paleogene global warmth and proposed increased freshwater discharge in the early Cenozoic. Specific source-related biomarkers including n-alkanes, fatty acids, isoprenoids, carotenoids, hopanes/hopenes, hopanoic acids, aromatic terpenoids, and long-chain alkenones show a high variability of components, derived from marine and terrestrial origin. The distribution of hopanoic acid isomers is dominated by compounds with the biological 17β(H), 21β(H) configuration indicating a low level of maturity. On the basis of the biomarker data the terrestrial OC supply was significantly enriched during the late Paleocene and part of the earliest Eocene, whereas increased aquatic contributions and euxinic conditions of variable intensity were determined for the Paleocene-Eocene thermal maximum and Eocene thermal maximum 2 events as well as the middle Eocene time interval. Furthermore, samples from the middle Eocene are characterized by the occurrence of long-chain alkenones, high proportions of lycopane, and high ratios (>0.6) of (n-C35 + lycopane)/n-C31. The occurrence of C37-alkenenones, which were first determined toward the end of the Azolla freshwater event, indicates that the OC becomes more marine in origin during the middle Eocene. Preliminary U37K'-based sea surface temperature (SST) values display a long-term temperature decrease of about 15°C during the time interval 49-44.5 Ma (25° to 10°C), coinciding with the global benthic δ18O cooling trend after the early Eocene climatic optimum. At about 46 Ma, parallel with onset of ice-rafted debris, SST (interpreted as summer temperatures

  18. Carbon export fluxes and export efficiency in the central Arctic during the record sea-ice minimum in 2012: a joint 234Th/238U and 210Po/210Pb study

    Science.gov (United States)

    Roca-Martí, Montserrat; Puigcorbé, Viena; Rutgers van der Loeff, Michiel M.; Katlein, Christian; Fernández-Méndez, Mar; Peeken, Ilka; Masqué, Pere

    2016-07-01

    The Arctic sea-ice extent reached a record minimum in September 2012. Sea-ice decline increases the absorption of solar energy in the Arctic Ocean, affecting primary production and the plankton community. How this will modulate the sinking of particulate organic carbon (POC) from the ocean surface remains a key question. We use the 234Th/238U and 210Po/210Pb radionuclide pairs to estimate the magnitude of the POC export fluxes in the upper ocean of the central Arctic in summer 2012, covering time scales from weeks to months. The 234Th/238U proxy reveals that POC fluxes at the base of the euphotic zone were very low (2 ± 2 mmol C m-2 d-1) in late summer. Relationships obtained between the 234Th export fluxes and the phytoplankton community suggest that prasinophytes contributed significantly to the downward fluxes, likely via incorporation into sea-ice algal aggregates and zooplankton-derived material. The magnitude of the depletion of 210Po in the upper water column over the entire study area indicates that particle export fluxes were higher before July/August than later in the season. 210Po fluxes and 210Po-derived POC fluxes correlated positively with sea-ice concentration, showing that particle sinking was greater under heavy sea-ice conditions than under partially ice-covered regions. Although the POC fluxes were low, a large fraction of primary production (>30%) was exported at the base of the euphotic zone in most of the study area during summer 2012, indicating a high export efficiency of the biological pump in the central Arctic.

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

    Directory of Open Access Journals (Sweden)

    Li-Jin Guo

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

  20. Plant biodiversity and soil nitrogen and carbon pools changes as a result of nitrogen deposition at permanent pine plots in Central Russia

    Science.gov (United States)

    Komarov, Alexander; Priputina, Irina; Zubkova, Elena; Shanin, Vladimir

    2014-05-01

    We present results of analysis of increased rates of atmospheric nitrogen deposition observed in Central Russia between 1960 and 2010, and dealt with air pollution by NOx, on a biodiversity and main pools of C and N in pine forests of Moscow region, Russia. Shifts in nitrogen availability of three pine plots have been analyzed using presence/absence records on dynamics of understory plant communities (chronosequence consisting of four surveys from 1959-61 up to 2003) and a set of specialist plant species as bioindicators of soil richness. Atmospheric N loads received by ecosystems in 1950-1960 were estimated equal 5-7 kg ha-1 yr-1 with N-NH4 prevalence. In 1975-1990, NOx were more severe air contaminants that increased the N loads up to 15-20 kg ha-1 yr-1. Because of the economic decline of soon after 1990, general air pollution and the N deposition rates in Moscow region reduced, but a short time later started to increase again. We assume that those changes might be caused by atmospheric N input rates and to examine this assumption (i) analyze of species composition in understory has been done using Ellenberg indicator values and Tsyganov interval ecological scales developed for European Russia, and (ii) modeling of dynamics of main C and N pools in forest have been additionally carried out using EFIMOD and ROMUL models. Two nitrogen deposition scenarios have been simulated: (i) the steady background rate of N deposition equal to the one in the middle of last century, and (ii) the real ambient level of N depositions in last 50 yrs. Results have confirmed changes of understory species composition sustaining an eutrophication have been revealed in all plots. Number of specialists which mark rich soil conditions increases from 1950 and reaches maximum at 1990 for all plots. There is a difference between sample plots. Increasing number of specialists for rich conditions is very expressed for the richest mixed pine-lime stand and mixed pine-oak stand. Number of

  1. Climate and human impacts on vegetation changes in central Guizhou, China: Carbon and oxygen isotopic records in a stalagmite from Yelang Cave

    Science.gov (United States)

    Lee, T.; Liu, Z.; Li, H.; Shen, C.

    2009-12-01

    High-resolution δ18O and δ13C records of a 13.5-cm long stalagmite from Yelang Cave, 60 km west of Guiyang in the southwestern China, have been established by 750 measurements. With low U (10~40 ppb) and Th (0.01~0.367 ppb), four ICP-MS 230Th/U dates indicate that the upper 5.5 cm part is younger than 1000 years, with clear calcite deposition. Below 6 cm depth where the age suddenly changed from late Holocene to late Pleistocene, the stalagmite shows the deposition alternating between white-pure calcite layers and dark-dirty carbonate layers. The dating samples below 6 cm depth have low U contents (26~41 ppb) but high Th concentrations (10~22 ppb) showing 230Th/U dates ranging from 11 ka to 25 ka with large uncertainties. Based on current chronologies, the δ18O and δ13C records exhibit different features in the late Holocene and late Pleistocene. During the past 1000 yrs (0~5.5 cm), the δ18O ranges from -12.0‰ to -9.0‰ (PDB), containing many 10-100 yrs variations with Δδ18O >1‰. The δ13C during this period varies between -7.4‰ and -1.9‰, showing no correlation with the δ18O. Prior to 10.7 ka (below 6 cm), the δ18O and δ13C strongly co-varied, indicating climatic control on the surface vegetation with wet climates (lighter δ18O) resulting in better vegetation (lighter δ13C). The δ13C during the past 1000 yrs had three long-term increasing trends and a sharp decreasing trend, reflecting human impacts on the surface vegetation. The δ13C increased from about -6‰ at ca. AD 1370 to -3.2‰ around AD 1580, illustrating the first deforestation caused by human activity due to large immigration in Ming Dynasty to the region. The δ13C fluctuated between -4.5‰ and -3.0‰ from AD 1580 to AD 1740, then increased to -2.0‰ around AD 1770 with an opposite δ18O trend. This second deforestation event might be caused a strong immigration in early Qing Dynasty due to mining demand. Karst desertification occurred in the area reflected by heavy δ13C

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

    Science.gov (United States)

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

    2016-01-01

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

  3. TrkA、TrkB和TrkC受体在大鼠三叉神经本体觉中枢通路上的表达%XPRESSION OF TrkA, TrkB and TrkC RECEPTORS IN THE CENTRAL PATHWAY OF TRIGEMINAL PROPRIOCEPTION IN THE RAT

    Institute of Scientific and Technical Information of China (English)

    张富兴; 黎振航; 李金莲; 岑國欣; 陳應城

    2004-01-01

    Objective To examine the distribution of high-affinity neurotrophin receptors, viz. TrkA, TrkB and TrkC receptors, in the four-order central pathway of trigeminal proprioception in the rat. Methods Avidin-biotin-peroxidase complex (ABC) method of immunohistochemistry with diaminobenzidine (DAB) as the chromogen was employed to identify the immunoreactive cells. Results All three receptors were detected in the mesencephalic trigeminal nucleus, the second-and third order nuclei iu the central pathway of trigeminal proprioception. Within each of these nuclei, cells immunostained for the three receptors differed in density. TrkA-and TrkB-immunostaining was observed on the cell bodies and processes; TrkB, however,labelled much longer processes. TrkC staining was mainly restricted to the cell bodies. Conclusion In the central pathway of the trigeminal proprioception, each of the three receptors may play a specific role in maintaining the survival of neurons and in regulating the neurotransmitter release.%目的检查高亲和性的神经营养物质受体(TrkA、TrkB和TrkC)在大鼠三叉神经本体觉中枢四级通路上的分布.方法采用免疫组织化学的抗生物素-生物素-过氧化物酶复合物(ABC)方法并以二氨基联苯胺(DAB)为呈色剂,检查免疫反应细胞.结果 3种受体在三叉神经本体觉中枢四级通路的三叉神经中脑核、二级和三级核团均有表达.同一核团内3种受体的免疫阳性细胞密度不同.在胞体和突起上均观察到TrkA和TrkB免疫反应染色,但TrkB标记的突起较长,TrkC染色多局限于细胞体部分.结论在三叉神经本体觉中枢通路中,3种神经营养物质受体都可能在维持神经元存活和调节递质释放等方面发挥特定的作用.

  4. Most blood biomarkers related to vitamin status, one-carbon metabolism, and the kynurenine pathway show adequate preanalytical stability and within-person reproducibility to allow assessment of exposure or nutritional status in healthy women and cardiovascular patients.

    Science.gov (United States)

    Midttun, Oivind; Townsend, Mary K; Nygård, Ottar; Tworoger, Shelley S; Brennan, Paul; Johansson, Mattias; Ueland, Per Magne

    2014-05-01

    Knowledge of stability during sample transportation and changes in biomarker concentrations within person over time are paramount for proper design and interpretation of epidemiologic studies based on a single measurement of biomarker status. Therefore, we investigated stability and intraindividual vs. interindividual variation in blood concentrations of biomarkers related to vitamin status, one-carbon metabolism, and the kynurenine pathway. Whole blood (EDTA and heparin, n = 12) was stored with an icepack for 24 or 48 h, and plasma concentrations of 38 biomarkers were determined. Stability was calculated as change per hour, intraclass correlation coefficient (ICC), and simple Spearman correlation. Within-person reproducibility of biomarkers was expressed as ICC in samples collected 1-2 y apart from 40 postmenopausal women and in samples collected up to 3 y apart from 551 patients with stable angina pectoris. Biomarker stability was similar in EDTA and heparin blood. Most biomarkers were essentially stable, except for choline and total homocysteine (tHcy), which increased markedly. Within-person reproducibility in postmenopausal women was excellent (ICC > 0.75) for cotinine, all-trans retinol, cobalamin, riboflavin, α-tocopherol, Gly, pyridoxal, methylmalonic acid, creatinine, pyridoxal 5'-phosphate, and Ser; was good to fair (ICC of 0.74-0.40) for pyridoxic acid, kynurenine, tHcy, cholecalciferol, flavin mononucleotide, kynurenic acid, xanthurenic acid, 3-hydroxykynurenine, sarcosine, anthranilic acid, cystathionine, homoarginine, 3-hydroxyanthranilic acid, betaine, Arg, folate, total cysteine, dimethylglycine, asymmetric dimethylarginine, neopterin, symmetric dimethylarginine, and Trp; and poor (ICC of 0.39-0.15) for methionine sulfoxide, Met, choline, and trimethyllysine. Similar reproducibilities were observed in patients with coronary heart disease. Thus, most biomarkers investigated were essentially stable in cooled whole blood for up to 48 h and had a

  5. Identification of Putative RuBisCo Activase (TaRca1)—The Catalytic Chaperone Regulating Carbon Assimilatory Pathway in Wheat (Triticum aestivum) under the Heat Stress

    Science.gov (United States)

    Goswami, Suneha; Singh, Khushboo; Dubey, Kavita; Singh, Shweta; Sharma, Renu; Verma, Neeraj; Kala, Yugal K.; Rai, Gyanendra K.; Grover, Monendra; Mishra, Dwijesh C.; Singh, Bhupinder; Pathak, Himanshu; Chinnusamy, Viswanathan; Rai, Anil; Praveen, Shelly

    2016-01-01

    RuBisCo activase (Rca) is a catalytic chaperone involved in modulating the activity of RuBisCo (key enzyme of photosynthetic pathway). Here, we identified eight novel transcripts from wheat through data mining predicted to be Rca and cloned a transcript of 1.4 kb from cv. HD2985, named as TaRca1 (GenBank acc. no. KC776912). Single copy number of TaRca1 was observed in wheat genome. Expression analysis in diverse wheat genotypes (HD2985, Halna, PBW621, and HD2329) showed very high relative expression of TaRca1 in Halna under control and HS-treated, as compared to other cultivars at different stages of growth. TaRca1 protein was predicted to be chloroplast-localized with numerous potential phosphorylation sites. Northern blot analysis showed maximum accumulation of TaRca1 transcript in thermotolerant cv. during mealy-ripe stage, as compared to thermosusceptible. Decrease in the photosynthetic parameters was observed in all the cultivars, except PBW621 in response to HS. We observed significant increase in the Rca activity in all the cultivars under HS at different stages of growth. HS causes decrease in the RuBisCo activity; maximum reduction was observed during pollination stage in thermosusceptible cvs. as validated through immunoblotting. We observed uniform carbon distribution in different tissues of thermotolerant cvs., as compared to thermosusceptible. Similarly, tolerance level of leaf was observed maximum in Halna having high Rca activity under HS. A positive correlation was observed between the transcript and activity of TaRca1 in HS-treated Halna. Similarly, TaRca1 enzyme showed positive correlation with the activity of RuBisCo. There is, however, need to manipulate the thermal stability of TaRca1 enzyme through protein engineering for sustaining the photosynthetic rate under HS—a novel approach toward development of “climate-smart” crop. PMID:27462325

  6. Auditory pathways: anatomy and physiology.

    Science.gov (United States)

    Pickles, James O

    2015-01-01

    This chapter outlines the anatomy and physiology of the auditory pathways. After a brief analysis of the external, middle ears, and cochlea, the responses of auditory nerve fibers are described. The central nervous system is analyzed in more detail. A scheme is provided to help understand the complex and multiple auditory pathways running through the brainstem. The multiple pathways are based on the need to preserve accurate timing while extracting complex spectral patterns in the auditory input. The auditory nerve fibers branch to give two pathways, a ventral sound-localizing stream, and a dorsal mainly pattern recognition stream, which innervate the different divisions of the cochlear nucleus. The outputs of the two streams, with their two types of analysis, are progressively combined in the inferior colliculus and onwards, to produce the representation of what can be called the "auditory objects" in the external world. The progressive extraction of critical features in the auditory stimulus in the different levels of the central auditory system, from cochlear nucleus to auditory cortex, is described. In addition, the auditory centrifugal system, running from cortex in multiple stages to the organ of Corti of the cochlea, is described.

  7. Highly efficient simultaneous ultrasonic assisted adsorption of brilliant green and eosin B onto ZnS nanoparticles loaded activated carbon: Artificial neural network modeling and central composite design optimization

    Science.gov (United States)

    Jamshidi, M.; Ghaedi, M.; Dashtian, K.; Ghaedi, A. M.; Hajati, S.; Goudarzi, A.; Alipanahpour, E.

    2016-01-01

    In this work, central composite design (CCD) combined with response surface methodology (RSM) and desirability function approach (DFA) gives useful information about operational condition and also to obtain useful information about interaction and main effect of variables concerned to simultaneous ultrasound-assisted removal of brilliant green (BG) and eosin B (EB) by zinc sulfide nanoparticles loaded on activated carbon (ZnS-NPs-AC). Spectra overlap between BG and EB dyes was extensively reduced and/or omitted by derivative spectrophotometric method, while multi-layer artificial neural network (ML-ANN) model learned with Levenberg-Marquardt (LM) algorithm was used for building up a predictive model and prediction of the BG and EB removal. The ANN efficiently was able to forecast the simultaneous BG and EB removal that was confirmed by reasonable numerical value i.e. MSE of 0.0021 and R2 of 0.9589 and MSE of 0.0022 and R2 of 0.9455 for testing data set, respectively. The results reveal acceptable agreement among experimental data and ANN predicted results. Langmuir as the best model for fitting experimental data relevant to BG and EB removal indicates high, economic and profitable adsorption capacity (258.7 and 222.2 mg g- 1) that supports and confirms its applicability for wastewater treatment.

  8. Highly efficient simultaneous ultrasonic assisted adsorption of brilliant green and eosin B onto ZnS nanoparticles loaded activated carbon: Artificial neural network modeling and central composite design optimization.

    Science.gov (United States)

    Jamshidi, M; Ghaedi, M; Dashtian, K; Ghaedi, A M; Hajati, S; Goudarzi, A; Alipanahpour, E

    2016-01-15

    In this work, central composite design (CCD) combined with response surface methodology (RSM) and desirability function approach (DFA) gives useful information about operational condition and also to obtain useful information about interaction and main effect of variables concerned to simultaneous ultrasound-assisted removal of brilliant green (BG) and eosin B (EB) by zinc sulfide nanoparticles loaded on activated carbon (ZnS-NPs-AC). Spectra overlap between BG and EB dyes was extensively reduced and/or omitted by derivative spectrophotometric method, while multi-layer artificial neural network (ML-ANN) model learned with Levenberg-Marquardt (LM) algorithm was used for building up a predictive model and prediction of the BG and EB removal. The ANN efficiently was able to forecast the simultaneous BG and EB removal that was confirmed by reasonable numerical value i.e. MSE of 0.0021 and R(2) of 0.9589 and MSE of 0.0022 and R(2) of 0.9455 for testing data set, respectively. The results reveal acceptable agreement among experimental data and ANN predicted results. Langmuir as the best model for fitting experimental data relevant to BG and EB removal indicates high, economic and profitable adsorption capacity (258.7 and 222.2 mg g(-1)) that supports and confirms its applicability for wastewater treatment.

  9. Premetazoan Origin of the Hippo Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Arnau Sebé-Pedrós

    2012-01-01

    Full Text Available Nonaggregative multicellularity requires strict control of cell number. The Hippo signaling pathway coordinates cell proliferation and apoptosis and is a central regulator of organ size in animals. Recent studies have shown the presence of key members of the Hippo pathway in nonbilaterian animals, but failed to identify this pathway outside Metazoa. Through comparative analyses of recently sequenced holozoan genomes, we show that Hippo pathway components, such as the kinases Hippo and Warts, the coactivator Yorkie, and the transcription factor Scalloped, were already present in the unicellular ancestors of animals. Remarkably, functional analysis of Hippo components of the amoeboid holozoan Capsaspora owczarzaki, performed in Drosophila melanogaster, demonstrate that the growth-regulatory activity of the Hippo pathway is conserved in this unicellular lineage. Our findings show that the Hippo pathway evolved well before the origin of Metazoa and highlight the importance of Hippo signaling as a key developmental mechanism predating the origin of Metazoa.

  10. central t

    Directory of Open Access Journals (Sweden)

    Manuel R. Piña Monarrez

    2007-01-01

    Full Text Available Dado que la Regresión Ridge (RR, es una estimación sesgada que parte de la solución de la regresión de Mínimos Cuadrados (MC, es vital establecer las condiciones para las que la distribución central t de Student que se utiliza en la prueba de hipótesis en MC, sea también aplicable a la regresión RR. La prueba de este importante resultado se presenta en este artículo.

  11. Central China’ s Low-carbon Development Competitiveness Assessment Oriented to People’ s Livehood and Well-being:Based on AHP-TOPSIS Methods%民生福祉导向下的中国中部地区低碳发展竞争力评价--基于AHP-TOPSIS模型的实证

    Institute of Scientific and Technical Information of China (English)

    王圣云; 廖纯韬; 许双喜; 黄敏

    2014-01-01

    Low carbon wave had a great impact on economic development in the Central China .As a scarce resource , carbon emission space has become new restrictions in the Central China .To enhance the sustainable com-petitiveness is a key to obtain a competitive advantage with the carbon constraints in the Central China .Region low-carbon development competitiveness is a capability of continuing to improve CO 2 emissions performance , and con-tinuously promote regional economic prosperity and enhance the well-being of residents within the carbon emissions constraints .Prerequisite for low-carbon development competitive is the low carbon development basis , the goal is the output of low carbon development , the core is the efficiency of low-carbon development , and the key is the low-carbon development potential .Using AHP-TOPSIS method , some conclusions has been drawn as follow:The com-prehensive low carbon development competitiveness of Hunan Province is first , Jiangxi Province is second;the wea-kest is Shanxi Province , Hubei Province is little weaker , Henan Province and Anhui Province is in the middle posi-tion.Drive pattern of low-carbon development competitive has a big difference between six provinces in Central Chi -na .Shanxi Province is mainly driven by the low-carbon development output competitive .Jiangxi Province is mainly driven by the basis competitiveness and efficiency competitive .Anhui Province is mainly driven by the low-carbon development efficiency competitive .Hubei Province is mainly driven by the basis potential competitiveness and out-put competitiveness .Henan Province is mainly driven by the basis competitiveness and potential competitiveness . Four low carbon development competitiveness of Hunan Province are relatively even .%在碳约束下提升区域竞争力是中部地区低碳发展获取竞争优势的关键所在。区域低碳发展竞争力是一个地区在碳约束下持续提高碳排放绩效、不断促进地区经济繁荣和

  12. A Central Role for JNK/AP-1 Pathway in the Pro-Oxidant Effect of Pyrrolidine Dithiocarbamate through Superoxide Dismutase 1 Gene Repression and Reactive Oxygen Species Generation in Hematopoietic Human Cancer Cell Line U937

    Science.gov (United States)

    Collin, Pascal; Lomri, Abderrahim

    2015-01-01

    Pyrrolidine dithiocarbamate (PDTC) known as antioxidant and specific inhibitor of NF-κB was also described as pro-oxidant by inducing cell death and reactive oxygen species (ROS) accumulation in cancer. However, the mechanism by which PDTC indices its pro-oxidant effect is unknown. Therefore, we aimed to evaluate the effect of PDTC on the human Cu/Zn superoxide dismutase 1 (SOD1) gene transcription in hematopoietic human cancer cell line U937. We herein show for the first time that PDTC decreases SOD1 transcripts, protein and promoter activity. Furthermore, SOD1 repression by PDTC was associated with an increase in oxidative stress as evidenced by ROS production. Electrophoretic mobility-shift assays (EMSA) show that PDTC increased binding of activating protein-1 (AP-1) in dose dependent-manner suggesting that the MAPkinase up-stream of AP-1 is involved. Ectopic NF-κB p65 subunit overexpression had no effect on SOD1 transcription. In contrast, in the presence of JNK inhibitor (SP600125), p65 induced a marked increase of SOD1 promoter, suggesting that JNK pathway is up-stream of NF-κB signaling and controls negatively its activity. Indeed, using JNK deficient cells, PDTC effect was not observed nether on SOD1 transcription or enzymatic activity, nor on ROS production. Finally, PDTC represses SOD1 in U937 cells through JNK/c-Jun phosphorylation. Taken together, these results suggest that PDTC acts as pro-oxidant compound in JNK/AP-1 dependent-manner by repressing the superoxide dismutase 1 gene leading to intracellular ROS accumulation. PMID:25996379

  13. 心内心电图下三种路径置入中心静脉导管的应用研究%Applied Research of Central Venous Catheter Via Three Pathways under the Intravenous Electrocardiogram

    Institute of Scientific and Technical Information of China (English)

    翟美琴; 逯豫霞; 赵砚丽; 吕从改

    2012-01-01

    Objective To discuss the use of central venous catheter under the intravenous electrocardiogram (IVECC). Methods 150 adult patients who would undergo selective operation of central venous catheterizations in general anesthesia were randomly divided into three groups, group A, B and C (n =50). Patients in group A received dexter internal jugular vein catheter-ization, patients in group B received dexter subclavian vein catheterization and in group C the dexter subclavian vein punctured and catheterization were performed. IVECC monitoring technology was applied in the three groups. We recorded the data of Lmax, Lact, Lpre and the value of Lmax - Lact and Lpre - Lmax respectively. The anteroposterior position of the X-ray examination after operation was taken to judge whether the catheter was in the right place or not. The standard of over-deep or ectopic for atrium dextrum was Lpre - Lmax ≥0.5 cm. Results 146 patients underwent paracentesis successfully, and 4 patients including one from group A, one from group B and two from group C failed in paracentesis. The average indexes of Lmax - Lact and Lpre - Lact were (2.4 ± 0.3) cm and(2.1 ±0.8)cm respectively in the 146 patients. There were 22 patients with Lpre -Lmax≥0. 5 cm (15.07% ) , including 7 patients in group A, 8 patients in group B and 7 patients in group C. The typical change was catheter tip being located at superior vena cava according to chest X-ray film postoperative. According to the results of IVECG and chest X-ray film, the patients with Lpre -Lmax≥0.5 cm canal were located in atrium dextrum and catheter placement coincidence rate was 100%. Conclusion IVECC assisted central venous catheter is easy to perform, does not have radio-active contamination and can replace X-ray examination.%目的 探讨在心内心电图(IVECG)辅助下置入中心静脉导管的可行性.方法 选择拟在全麻下行择期手术需放置中心静脉导管的成年患者150例,随机分为A、B、C3组,每组50例,

  14. Determination of 222Rn in water by absorption in polydimethylsiloxane mixed with activated carbon and gamma-ray spectrometry: An example application in the radon budget of Paterno submerged sinkhole (Central Italy)

    International Nuclear Information System (INIS)

    Highlights: ► Polydimethylsiloxane and Activated Carbon were used as passive gas accumulator. ► Water-impermeable properties of PDMS combine with adsorptive properties of AC. ► PDMS–AC accumulators can be used to study 222Rn in water. ► Measured 222Rn specific activity in PDMS–AC matches the theoretical results. ► We used PDMS–AC in the radon budget of a submerged sinkhole. - Abstract: Passive gas accumulators made of polydimethylsiloxane (PDMS) mixed with activated C (AC) were studied to measure their efficiency for sampling Rn in water. In this composite the water-impermeable properties of PDMS act synergistically with adsorptive properties of AC, even when the accumulators are immersed in water for many days. A series of tests where cylindrical shaped PDMS–AC disks were exposed to different 222Rn-enriched waters showed that measured 222Rn specific activity matches the theoretical results coming from the equation that describes the process of internal diffusion integrated with the Rn decay term. The linear relationship between 222Rn in water and the accumulation process in PDMS–AC, the influence of temperature and the different sensitivity of the composite and its components were also studied and discussed. The high Rn volumetric enrichment factor in PDMS–AC disks respect to water resulted in about 206: 1, so lowering detection limits for 222Rn in water to 20 Bq m−3 when the total activity of Rn progeny in disks is measured by high resolution gamma-ray spectrometry. The use of PDMS–AC accumulators was tested at the Paterno submerged sinkhole, in central Italy. This study allowed the production of a detailed synchronous vertical profile of the Rn content in the middle of the lake and to define the Rn balance by assessing the discharge rate of submerged springs and the average residence time of the lake water

  15. Carbon partitioning in photosynthesis.

    Science.gov (United States)

    Melis, Anastasios

    2013-06-01

    The work seeks to raise awareness of a fundamental problem that impacts the renewable generation of fuels and chemicals via (photo)synthetic biology. At issue is regulation of the endogenous cellular carbon partitioning between different biosynthetic pathways, over which the living cell exerts stringent control. The regulation of carbon partitioning in photosynthesis is not understood. In plants, microalgae and cyanobacteria, methods need be devised to alter photosynthetic carbon partitioning between the sugar, terpenoid, and fatty acid biosynthetic pathways, to lower the prevalence of sugar biosynthesis and correspondingly upregulate terpenoid and fatty acid hydrocarbons production in the cell. Insight from unusual but naturally occurring carbon-partitioning processes can help in the design of blueprints for improved photosynthetic fuels and chemicals production.

  16. Non-enzymatic glycolysis and pentose phosphate pathway-like reactions in a plausible Archean ocean.

    Science.gov (United States)

    Keller, Markus A; Turchyn, Alexandra V; Ralser, Markus

    2014-04-25

    The reaction sequences of central metabolism, glycolysis and the pentose phosphate pathway provide essential precursors for nucleic acids, amino acids and lipids. However, their evolutionary origins are not yet understood. Here, we provide evidence that their structure could have been fundamentally shaped by the general chemical environments in earth's earliest oceans. We reconstructed potential scenarios for oceans of the prebiotic Archean based on the composition of early sediments. We report that the resultant reaction milieu catalyses the interconversion of metabolites that in modern organisms constitute glycolysis and the pentose phosphate pathway. The 29 observed reactions include the formation and/or interconversion of glucose, pyruvate, the nucleic acid precursor ribose-5-phosphate and the amino acid precursor erythrose-4-phosphate, antedating reactions sequences similar to that used by the metabolic pathways. Moreover, the Archean ocean mimetic increased the stability of the phosphorylated intermediates and accelerated the rate of intermediate reactions and pyruvate production. The catalytic capacity of the reconstructed ocean milieu was attributable to its metal content. The reactions were particularly sensitive to ferrous iron Fe(II), which is understood to have had high concentrations in the Archean oceans. These observations reveal that reaction sequences that constitute central carbon metabolism could have been constrained by the iron-rich oceanic environment of the early Archean. The origin of metabolism could thus date back to the prebiotic world.

  17. Pathway projector: web-based zoomable pathway browser using KEGG atlas and Google Maps API.

    Directory of Open Access Journals (Sweden)

    Nobuaki Kono

    Full Text Available BACKGROUND: Biochemical pathways provide an essential context for understanding comprehensive experimental data and the systematic workings of a cell. Therefore, the availability of online pathway browsers will facilitate post-genomic research, just as genome browsers have contributed to genomics. Many pathway maps have been provided online as part of public pathway databases. Most of these maps, however, function as the gateway interface to a specific database, and the comprehensiveness of their represented entities, data mapping capabilities, and user interfaces are not always sufficient for generic usage. METHODOLOGY/PRINCIPAL FINDINGS: We have identified five central requirements for a pathway browser: (1 availability of large integrated maps showing genes, enzymes, and metabolites; (2 comprehensive search features and data access; (3 data mapping for transcriptomic, proteomic, and metabolomic experiments, as well as the ability to edit and annotate pathway maps; (4 easy exchange of pathway data; and (5 intuitive user experience without the requirement for installation and regular maintenance. According to these requirements, we have evaluated existing pathway databases and tools and implemented a web-based pathway browser named Pathway Projector as a solution. CONCLUSIONS/SIGNIFICANCE: Pathway Projector provides integrated pathway maps that are based upon the KEGG Atlas, with the addition of nodes for genes and enzymes, and is implemented as a scalable, zoomable map utilizing the Google Maps API. Users can search pathway-related data using keywords, molecular weights, nucleotide sequences, and amino acid sequences, or as possible routes between compounds. In addition, experimental data from transcriptomic, proteomic, and metabolomic analyses can be readily mapped. Pathway Projector is freely available for academic users at (http://www.g-language.org/PathwayProjector/.

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

    Directory of Open Access Journals (Sweden)

    Christopher J Alteri

    2015-01-01

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

  19. Focal lesions in the central nervous system

    International Nuclear Information System (INIS)

    This report reviews the animal and human studies currently in progress at LBL with heavy-ion beams to induce focal lesions in the central nervous system, and discusses the potential future prospects of fundamental and applied brain research with heavy-ion beams. Methods are being developed for producing discrete focal lesions in the central nervous system using the Bragg ionization peak to investigate nerve pathways and neuroendocrine responses, and for treating pathological disorders of the brain

  20. Pathways to deep decarbonization in India

    DEFF Research Database (Denmark)

    Shukla, P.; Dhar, Subash; Pathak, Minal;

    This report is a part of the global Deep Decarbonisation Pathways (DDP) Project. The analysis consider two development scenarios for India and assess alternate roadmaps for transiting to a low carbon economy consistent with the globally agreed 2°C stabilization target. The report does not consider...

  1. Carbon dioxide, hydrographic, and chemical data obtained in the Central South Pacific Ocean (WOCE sections P17S and P16S) during the tunes-2-expedition of the R/V Thomas Washington, July--August 1991

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1991-12-31

    This data documentation discusses the procedures and methods used to measure total carbon dioxide (TCO{sub 2}), discrete partial pressure of TCO{sub 2} (pCO{sub 2}), and total alkalinity (TALK), during the Research Vessel (R/V) Thomas Washington TUNES Leg 2 Expedition in the central South Pacific Ocean. Conducted as part of the World Ocean Circulation Experiment (WOCE), the cruise began in Papeete, Tahiti, French Polynesia, on July 16, 1991, and returned to Papeete on August 25, 1991. WOCE Meridional Sections P17S along 135{degrees} W and P16S along 150{degrees} W were completed during the 40-day expedition. A total of 97 hydrographic stations were occupied. Hydrographic and chemical measurements made along WOCE Sections P17S and P16S included pressure, temperature, salinity, and oxygen measured by conductivity, temperature and depth sensor; bottle salinity; oxygen; phosphate; nitrate; nitrite; silicate; CFC-12; CFC- 11; TCO{sub 2}; TALK; and pCO{sub 2} measured at 20{degrees}C. The TCO{sub 2} concentration in 1000 seawater samples was determined with a coulometric analysis system, the pCO{sub 2} in 940 water samples was determined with an equilibrator/gas chromatograph system, while the TALK concentration in 139 samples was determined on shore at the laboratory of C. Goyet of Woods Hole Oceanographic Institution with an alkalinity titration system. In addition, 156 coulometric measurements for the Certified Reference Material (Batch {number_sign}6) were made and yielded a mean value of 2303.2 {plus_minus} 1.5 {mu}mol/kg. This mean value agrees within a standard deviation of the 2304.6 {plus_minus} 1.6 {mu}mol/kg (N=9) value determined with the manometer of C. D. Keeling at Scripps Institution of Oceanography (SIO). Replicate samples from 11 Ni