WorldWideScience

Sample records for c4 species

  1. Why Are C3-C4 Intermediate Species Rare?

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    Johnson, J. E.; Field, C. B.; Berry, J. A.

    2014-12-01

    While C3-C4 intermediate photosynthesis is thought to represent the evolutionary bridge between C3 and C4 photosynthesis, C3-C4 intermediate species are ecologically rare in comparison to both C3 and C4 species. Here, we report results from a laboratory experiment, field observations, and model simulations that suggest a new explanation for the ecological rarity of C3-C4 intermediate species. In the laboratory experiment, we combined gas exchange and fluorescence to characterize the temperature response of photosynthesis in three closely-related species in the genus Flaveria that are representatives of the C3, C3-C4 intermediate, and C4 photosynthetic pathways. The leaf temperature that maximized the quantum yield for CO2 assimilation (Topt(ΦCO2)) was 24.9 ± 0.7°C in Flaveria robusta (C3), 29.8 ± 1.0°C in F. chloraefolia (C3-C4), and 35.7 ± 0.8°C in F. bidentis (C4), and was linearly related to the temperature sensitivity of the coupling between CO2 assimilation and electron transport (d(ΦCO2/ ΦPSII)/dT)). While F. chloraefolia does not simultaneously occur with F. robusta and F. bidentis in naturally-assembled communities, this C3-C4 intermediate species does occur with other C3 and C4 species. During the growing season in two of these mixed-photosynthetic-type communities, leaf temperatures for F. chloraefolia were similar to the Topt(ΦCO2) determined in the laboratory. A model of maximum potential carbon gain suggests that competitive coexistence of C3, C3-C4 intermediate, and C4 species could be dependent on a temperature regime that highlights the distinct relative advantages of the C3-C4 intermediate pathway. In combination, these results suggest that the relative temperature sensitivity of the C3, C3-C4 intermediate, and C4 photosynthetic pathways combined with environmental variation in temperature may help to explain why C3-C4 intermediate species are generally rare.

  2. Glycine decarboxylase in C3, C4 and C3-C4 intermediate species.

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    Schulze, Stefanie; Westhoff, Peter; Gowik, Udo

    2016-06-01

    The glycine decarboxylase complex (GDC) plays a central role in photorespiration. GDC is localized in the mitochondria and together with serine hydroxymethyltransferase it converts two molecules of glycine to one molecule of serine, CO2 and NH3. Overexpression of GDC subunits in the C3 species Arabidopsis thaliana can increase the metabolic flux through the photorespiratory pathway leading to enhanced photosynthetic efficiency and consequently to an enhanced biomass production of the transgenic plants. Changing the spatial expression patterns of GDC subunits was an important step during the evolution of C3-C4 intermediate and likely also C4 plants. Restriction of the GDC activity to the bundle sheath cells led to the establishment of a photorespiratory CO2 pump. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Wild Manihot Species Do Not Possess C4 Photosynthesis

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    CALATAYUD, P.‐A.; BARÓN, C. H.; VELÁSQUEZ, H.; ARROYAVE, J. A.; LAMAZE, T.

    2002-01-01

    Cultivated cassava (Manihot esculenta) has a higher rate of photosynthesis than is usual for C3 plants and photosynthesis is not light saturated. For these reasons it has been suggested that cultivated cassava could be derived from wild species possessing C4 photosynthesis. The natural abundance of 13C and activities of phosphoenolpyruvate carboxylase and phosphoglycolate phosphatase were measured in leaves of 20 wild cassava species to test this hypothesis. All the species studied, including M. flabellifolia the potential wild progenitor of cultivated cassava, clearly exhibited C3 not C4 characteristics. PMID:12096814

  4. Major alterations in transcript profiles between C3-C4 and C4 photosynthesis of an amphibious species Eleocharis baldwinii.

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    Chen, Taiyu; Zhu, Xin-Guang; Lin, Yongjun

    2014-09-01

    Engineering C4 photosynthetic metabolism into C3 crops is regarded as a major strategy to increase crop productivity, and clarification of the evolutionary processes of C4 photosynthesis can help the better use of this strategy. Here, Eleocharis baldwinii, a species in which C4 photosynthesis can be induced from a C3-C4 state under either environmental or ABA treatments, was used to identify the major transcriptional modifications during the process from C3-C4 to C4. The transcriptomic comparison suggested that in addition to the major differences in C4 core pathway, the pathways of glycolysis, citrate acid metabolism and protein synthesis were dramatically modified during the inducement of C4 photosynthetic states. Transcripts of many transporters, including not only metabolite transporters but also ion transporters, were dramatically increased in C4 photosynthetic state. Many candidate regulatory genes with unidentified functions were differentially expressed in C3-C4 and C4 photosynthetic states. Finally, it was indicated that ABA, auxin signaling and DNA methylation play critical roles in the regulation of C4 photosynthesis. In summary, by studying the different photosynthetic states of the same species, this work provides the major transcriptional differences between C3-C4 and C4 photosynthesis, and many of the transcriptional differences are potentially related to C4 development and therefore are the potential targets for reverse genetics studies.

  5. Towards an integrative model of C4 photosynthetic subtypes: insights from comparative transcriptome analysis of NAD-ME, NADP-ME, and PEP-CK C4 species

    OpenAIRE

    Bräutigam, A.; Schliesky, S.; Külahoglu, C.; Osborne, C. P.; Weber, A. P. M.

    2014-01-01

    C4 photosynthesis affords higher photosynthetic carbon conversion efficiency than C3 photosynthesis and it therefore represents an attractive target for engineering efforts aiming to improve crop productivity. To this end, blueprints are required that reflect C4 metabolism as closely as possible. Such blueprints have been derived from comparative transcriptome analyses of C3 species with related C4 species belonging to the NAD-malic enzyme (NAD-ME) and NADP-ME subgroups of C4 photosynthesis. ...

  6. Germination shifts of C3 and C4 species under simulated global warming scenario.

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    Hongxiang Zhang

    Full Text Available Research efforts around the world have been increasingly devoted to investigating changes in C3 and C4 species' abundance or distribution with global warming, as they provide important insight into carbon fluxes and linked biogeochemical cycles. However, changes in the early life stage (e.g. germination of C3 and C4 species in response to global warming, particularly with respect to asymmetric warming, have received less attention. We investigated germination percentage and rate of C3 and C4 species under asymmetric (+3/+6°C at day/night and symmetric warming (+5/+5°C at day/night, simulated by alternating temperatures. A thermal time model was used to calculate germination base temperature and thermal time constant. Two additional alternating temperature regimes were used to test temperature metrics effect. The germination percentage and rate increased continuously for C4 species, but increased and then decreased with temperature for C3 species under both symmetric and asymmetric warming. Compared to asymmetric warming, symmetric warming significantly overestimated the speed of germination percentage change with temperature for C4 species. Among the temperature metrics (minimum, maximum, diurnal temperature range and average temperature, maximum temperature was most correlated with germination of C4 species. Our results indicate that global warming may favour germination of C4 species, at least for the C4 species studied in this work. The divergent effects of asymmetric and symmetric warming on plant germination also deserve more attention in future studies.

  7. Germination shifts of C3 and C4 species under simulated global warming scenario.

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    Zhang, Hongxiang; Yu, Qiang; Huang, Yingxin; Zheng, Wei; Tian, Yu; Song, Yantao; Li, Guangdi; Zhou, Daowei

    2014-01-01

    Research efforts around the world have been increasingly devoted to investigating changes in C3 and C4 species' abundance or distribution with global warming, as they provide important insight into carbon fluxes and linked biogeochemical cycles. However, changes in the early life stage (e.g. germination) of C3 and C4 species in response to global warming, particularly with respect to asymmetric warming, have received less attention. We investigated germination percentage and rate of C3 and C4 species under asymmetric (+3/+6°C at day/night) and symmetric warming (+5/+5°C at day/night), simulated by alternating temperatures. A thermal time model was used to calculate germination base temperature and thermal time constant. Two additional alternating temperature regimes were used to test temperature metrics effect. The germination percentage and rate increased continuously for C4 species, but increased and then decreased with temperature for C3 species under both symmetric and asymmetric warming. Compared to asymmetric warming, symmetric warming significantly overestimated the speed of germination percentage change with temperature for C4 species. Among the temperature metrics (minimum, maximum, diurnal temperature range and average temperature), maximum temperature was most correlated with germination of C4 species. Our results indicate that global warming may favour germination of C4 species, at least for the C4 species studied in this work. The divergent effects of asymmetric and symmetric warming on plant germination also deserve more attention in future studies.

  8. De novo Transcriptome Assembly and Comparison of C3, C3-C4, and C4 Species of Tribe Salsoleae (Chenopodiaceae

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    Maximilian Lauterbach

    2017-11-01

    Full Text Available C4 photosynthesis is a carbon-concentrating mechanism that evolved independently more than 60 times in a wide range of angiosperm lineages. Among other alterations, the evolution of C4 from ancestral C3 photosynthesis requires changes in the expression of a vast number of genes. Differential gene expression analyses between closely related C3 and C4 species have significantly increased our understanding of C4 functioning and evolution. In Chenopodiaceae, a family that is rich in C4 origins and photosynthetic types, the anatomy, physiology and phylogeny of C4, C2, and C3 species of Salsoleae has been studied in great detail, which facilitated the choice of six samples of five representative species with different photosynthetic types for transcriptome comparisons. mRNA from assimilating organs of each species was sequenced in triplicates, and sequence reads were de novo assembled. These novel genetic resources were then analyzed to provide a better understanding of differential gene expression between C3, C2 and C4 species. All three analyzed C4 species belong to the NADP-ME type as most genes encoding core enzymes of this C4 cycle are highly expressed. The abundance of photorespiratory transcripts is decreased compared to the C3 and C2 species. Like in other C4 lineages of Caryophyllales, our results suggest that PEPC1 is the C4-specific isoform in Salsoleae. Two recently identified transporters from the PHT4 protein family may not only be related to the C4 syndrome, but also active in C2 photosynthesis in Salsoleae. In the two populations of the C2 species S. divaricata transcript abundance of several C4 genes are slightly increased, however, a C4 cycle is not detectable in the carbon isotope values. Most of the core enzymes of photorespiration are highly increased in the C2 species compared to both C3 and C4 species, confirming a successful establishment of the C2 photosynthetic pathway. Furthermore, a function of PEP-CK in C2 photosynthesis

  9. Mesophyll Chloroplast Investment in C3, C4 and C2 Species of the Genus Flaveria.

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    Stata, Matt; Sage, Tammy L; Hoffmann, Natalie; Covshoff, Sarah; Ka-Shu Wong, Gane; Sage, Rowan F

    2016-05-01

    The mesophyll (M) cells of C4 plants contain fewer chloroplasts than observed in related C3 plants; however, it is uncertain where along the evolutionary transition from C3 to C4 that the reduction in M chloroplast number occurs. Using 18 species in the genus Flaveria, which contains C3, C4 and a range of C3-C4 intermediate species, we examined changes in chloroplast number and size per M cell, and positioning of chloroplasts relative to the M cell periphery. Chloroplast number and coverage of the M cell periphery declined in proportion to increasing strength of C4 metabolism in Flaveria, while chloroplast size increased with increasing C4 cycle strength. These changes increase cytosolic exposure to the cell periphery which could enhance diffusion of inorganic carbon to phosphenolpyruvate carboxylase (PEPC), a cytosolic enzyme. Analysis of the transcriptome from juvenile leaves of nine Flaveria species showed that the transcript abundance of four genes involved in plastid biogenesis-FtsZ1, FtsZ2, DRP5B and PARC6-was negatively correlated with variation in C4 cycle strength and positively correlated with M chloroplast number per planar cell area. Chloroplast size was negatively correlated with abundance of FtsZ1, FtsZ2 and PARC6 transcripts. These results indicate that natural selection targeted the proteins of the contractile ring assembly to effect the reduction in chloroplast numbers in the M cells of C4 Flaveria species. If so, efforts to engineer the C4 pathway into C3 plants might evaluate whether inducing transcriptome changes similar to those observed in Flaveria could reduce M chloroplast numbers, and thus introduce a trait that appears essential for efficient C4 function. © The Author 2016. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  10. Towards an integrative model of C4 photosynthetic subtypes: insights from comparative transcriptome analysis of NAD-ME, NADP-ME, and PEP-CK C4 species.

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    Bräutigam, Andrea; Schliesky, Simon; Külahoglu, Canan; Osborne, Colin P; Weber, Andreas P M

    2014-07-01

    C4 photosynthesis affords higher photosynthetic carbon conversion efficiency than C3 photosynthesis and it therefore represents an attractive target for engineering efforts aiming to improve crop productivity. To this end, blueprints are required that reflect C4 metabolism as closely as possible. Such blueprints have been derived from comparative transcriptome analyses of C3 species with related C4 species belonging to the NAD-malic enzyme (NAD-ME) and NADP-ME subgroups of C4 photosynthesis. However, a comparison between C3 and the phosphoenolpyruvate carboxykinase (PEP-CK) subtype of C4 photosynthesis is still missing. An integrative analysis of all three C4 subtypes has also not been possible to date, since no comparison has been available for closely related C3 and PEP-CK C4 species. To generate the data, the guinea grass Megathyrsus maximus, which represents a PEP-CK species, was analysed in comparison with a closely related C3 sister species, Dichanthelium clandestinum, and with publicly available sets of RNA-Seq data from C4 species belonging to the NAD-ME and NADP-ME subgroups. The data indicate that the core C4 cycle of the PEP-CK grass M. maximus is quite similar to that of NAD-ME species with only a few exceptions, such as the subcellular location of transfer acid production and the degree and pattern of up-regulation of genes encoding C4 enzymes. One additional mitochondrial transporter protein was associated with the core cycle. The broad comparison identified sucrose and starch synthesis, as well as the prevention of leakage of C4 cycle intermediates to other metabolic pathways, as critical components of C4 metabolism. Estimation of intercellular transport fluxes indicated that flux between cells is increased by at least two orders of magnitude in C4 species compared with C3 species. In contrast to NAD-ME and NADP-ME species, the transcription of photosynthetic electron transfer proteins was unchanged in PEP-CK. In summary, the PEP-CK blueprint of M

  11. Unique photosynthetic phenotypes in Portulaca (Portulacaceae): C3-C4 intermediates and NAD-ME C4 species with Pilosoid-type Kranz anatomy.

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    Voznesenskaya, Elena V; Koteyeva, Nuria K; Edwards, Gerald E; Ocampo, Gilberto

    2017-01-01

    Portulacaceae is a family that has considerable diversity in photosynthetic phenotypes. It is one of 19 families of terrestrial plants where species having C4 photosynthesis have been found. Most species in Portulaca are in the alternate-leaved (AL) lineage, which includes one clade (Cryptopetala) with taxa lacking C4 photosynthesis and three clades having C4 species (Oleracea, Umbraticola and Pilosa). All three species in the Cryptopetala clade lack Kranz anatomy, the leaves have C3-like carbon isotope composition and they have low levels of C4 cycle enzymes. Anatomical, biochemical and physiological analyses show they are all C3-C4 intermediates. They have intermediate CO2 compensation points, enrichment of organelles in the centripetal position in bundle sheath (BS) cells, with selective localization of glycine decarboxylase in BS mitochondria. In the three C4 clades there are differences in Kranz anatomy types and form of malic enzyme (ME) reported to function in C4 (NAD-ME versus NADP-ME): Oleracea (Atriplicoid, NAD-ME), Umbraticola (Atriplicoid, NADP-ME) and Pilosa (Pilosoid, NADP-ME). Structural and biochemical analyses were performed on Pilosa clade representatives having Pilosoid-type leaf anatomy with Kranz tissue enclosing individual peripheral vascular bundles and water storage in the center of the leaf. In this clade, all species except P. elatior are NADP-ME-type C4 species with grana-deficient BS chloroplasts and grana-enriched M chloroplasts. Surprisingly, P. elatior has BS chloroplasts enriched in grana and NAD-ME-type photosynthesis. The results suggest photosynthetic phenotypes were probably derived from an ancestor with NADP-ME-type C4, with two independent switches to NAD-ME type. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  12. Optional use of CAM photosynthesis in two C4 species, Portulaca cyclophylla and Portulaca digyna.

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    Holtum, Joseph A M; Hancock, Lillian P; Edwards, Erika J; Winter, Klaus

    2017-07-01

    Low levels of crassulacean acid metabolism (CAM) are demonstrated in two species with C4 photosynthesis, Portulaca cyclophylla and P. digyna. The expression of CAM in P. cyclophylla and P. digyna is facultative, i.e. optional. Well-watered plants did not accumulate acid at night and exhibited gas-exchange patterns consistent with C4 photosynthesis. CAM-type nocturnal acidification was reversible in that it was induced following drought and lost when droughted plants were rewatered. In P. cyclophylla, droughting was accompanied by a small but discernible net uptake of CO2 during the dark, whereas in P. digyna, net CO2 exchange at night approached the CO2 compensation point but did not transition beyond it. This report brings the number of known C4 species with a capacity for expressing CAM to six. All are species of Portulaca. The observation of CAM in P. cyclophylla and P. digyna is the first for species in the opposite-leaved (OL) Portulacelloid-anatomy lineage of Portulaca and for the Australian clade therein. The other four species are within the alternate-leaved (AL) lineage, in the Atriploid-anatomy Oleracea and the Pilosoid-anatomy Pilosa clades. Studies of the evolutionary origins of C4 and CAM in Portulaca will benefit from a more wide-range survey of CAM across its species, particularly in the C3-C4 intermediate-containing Cryptopetala clade. Copyright © 2017 Elsevier GmbH. All rights reserved.

  13. Initial events during the evolution of C4 photosynthesis in C3 species of Flaveria.

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    Sage, Tammy L; Busch, Florian A; Johnson, Daniel C; Friesen, Patrick C; Stinson, Corey R; Stata, Matt; Sultmanis, Stefanie; Rahman, Beshar A; Rawsthorne, Stephen; Sage, Rowan F

    2013-11-01

    The evolution of C4 photosynthesis in many taxa involves the establishment of a two-celled photorespiratory CO2 pump, termed C2 photosynthesis. How C3 species evolved C2 metabolism is critical to understanding the initial phases of C4 plant evolution. To evaluate early events in C4 evolution, we compared leaf anatomy, ultrastructure, and gas-exchange responses of closely related C3 and C2 species of Flaveria, a model genus for C4 evolution. We hypothesized that Flaveria pringlei and Flaveria robusta, two C3 species that are most closely related to the C2 Flaveria species, would show rudimentary characteristics of C2 physiology. Compared with less-related C3 species, bundle sheath (BS) cells of F. pringlei and F. robusta had more mitochondria and chloroplasts, larger mitochondria, and proportionally more of these organelles located along the inner cell periphery. These patterns were similar, although generally less in magnitude, than those observed in the C2 species Flaveria angustifolia and Flaveria sonorensis. In F. pringlei and F. robusta, the CO2 compensation point of photosynthesis was slightly lower than in the less-related C3 species, indicating an increase in photosynthetic efficiency. This could occur because of enhanced refixation of photorespired CO2 by the centripetally positioned organelles in the BS cells. If the phylogenetic positions of F. pringlei and F. robusta reflect ancestral states, these results support a hypothesis that increased numbers of centripetally located organelles initiated a metabolic scavenging of photorespired CO2 within the BS. This could have facilitated the formation of a glycine shuttle between mesophyll and BS cells that characterizes C2 photosynthesis.

  14. Protoplast isolation and transient gene expression in the single-cell C4 species, Bienertia sinuspersici.

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    Lung, Shiu-Cheung; Yanagisawa, Makoto; Chuong, Simon D X

    2011-04-01

    Although transient gene expression using reporters such as green fluorescent protein is a versatile tool for examining gene functions and intracellular protein trafficking, the establishment of a highly efficient gene manipulation method remains a challenge in many plant species. A reliable transformation protocol has not yet been established for the three single-cell C(4) species, despite their potential of serving as model systems for their extraordinary C(4) photosynthetic metabolism. We report the first protocol optimized for isolating a large-scale and homogenous population of protoplasts from chlorenchyma cells of the single-cell C(4) species Bienertia sinuspersici. Cytochemical staining confirmed the preservation of the unusual subcellular compartmentation of organelles in chlorenchyma cells after cell wall digestion. Approximately 84% of isolated protoplasts expressed the reporter fluorescent protein following our optimized polyethylene glycol-mediated transfection procedures. Fluorescent fusion protein tagged with various intracellular sorting signals demonstrated potential use of the transient gene expression system in subcellular protein localization and organelle dynamics studies. Further applications of the current protoplast isolation and transfection techniques in understanding the novel single-cell C(4) photosynthetic mechanism are discussed.

  15. Co-regulation of dark and light reactions in three biochemical subtypes of C(4) species.

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    Kiirats, Olavi; Kramer, David M; Edwards, Gerald E

    2010-08-01

    Regulation of light harvesting in response to changes in light intensity, CO(2) and O(2) concentration was studied in C(4) species representing three different metabolic subtypes: Sorghum bicolor (NADP-malic enzyme), Amaranthus edulis (NAD-malic enzyme), and Panicum texanum (PEP-carboxykinase). Several photosynthetic parameters were measured on the intact leaf level including CO(2) assimilation rates, O(2) evolution, photosystem II activities, thylakoid proton circuit and dissipation of excitation energy. Gross rates of O(2) evolution (J(O)₂'), measured by analysis of chlorophyll fluorescence), net rates of O(2) evolution and CO(2) assimilation responded in parallel to changes in light and CO(2) levels. The C(4) subtypes had similar energy requirements for photosynthesis since there were no significant differences in maximal quantum efficiencies for gross rates of O(2) evolution (average value = 0.072 O(2)/quanta absorbed, approximately 14 quanta per O(2) evolved). At saturating actinic light intensities, when photosynthesis was suppressed by decreasing CO(2), ATP synthase proton conductivity (g (H) (+)) responded strongly to changes in electron flow, decreasing linearly with J(O)₂', which was previously observed in C(3) plants. It is proposed that g (H) (+) is controlled at the substrate level by inorganic phosphate availability. The results suggest development of nonphotochemical quenching in C(4) plants is controlled by a decrease in g (H) (+), which causes an increase in proton motive force by restricting proton efflux from the lumen, rather than by cyclic or pseudocyclic electron flow.

  16. Differences in photosynthetic responses of NADP-ME type C4 species to high light.

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    Romanowska, Elżbieta; Buczyńska, Alicja; Wasilewska, Wioleta; Krupnik, Tomasz; Drożak, Anna; Rogowski, Paweł; Parys, Eugeniusz; Zienkiewicz, Maksymilian

    2017-03-01

    Three species chosen as representatives of NADP-ME C4 subtype exhibit different sensitivity toward photoinhibition, and great photochemical differences were found to exist between the species. These characteristics might be due to the imbalance in the excitation energy between the photosystems present in M and BS cells, and also due to that between species caused by the penetration of light inside the leaves. Such regulation in the distribution of light intensity between M and BS cells shows that co-operation between both the metabolic systems determines effective photosynthesis and reduces the harmful effects of high light on the degradation of PSII through the production of reactive oxygen species (ROS). We have investigated several physiological parameters of NADP-ME-type C4 species (e.g., Zea mays, Echinochloa crus-galli, and Digitaria sanguinalis) grown under moderate light intensity (200 µmol photons m-2 s-1) and, subsequently, exposed to excess light intensity (HL, 1600 µmol photons m-2 s-1). Our main interest was to understand why these species, grown under identical conditions, differ in their responses toward high light, and what is the physiological significance of these differences. Among the investigated species, Echinochloa crus-galli is best adapted to HL treatment. High resistance of the photosynthetic apparatus of E. crus-galli to HL was accompanied by an elevated level of phosphorylation of PSII proteins, and higher values of photochemical quenching, ATP/ADP ratio, activity of PSI and PSII complexes, as well as integrity of the thylakoid membranes. It was also shown that the non-radiative dissipation of energy in the studied plants was not dependent on carotenoid contents and, thus, other photoprotective mechanisms might have been engaged under HL stress conditions. The activity of the enzymes superoxide dismutase and ascorbate peroxidase as well as the content of malondialdehyde and H2O2 suggests that antioxidant defense is not responsible

  17. Study of Flowering Pattern in Setaria viridis, a Proposed Model Species for C4 Photosynthesis Research

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    Govinda Rizal

    2013-01-01

    Full Text Available Green foxtail millet (Setaria viridis has NADP-ME type of C4 photosynthesis. Because of its short life cycle, small genome size of ~515 Mb, small plant stature, high number of seed set, simple growth requirements, and wide adaptability, this diploid (2n=18 weed is proposed to be a model species for the study of C4 photosynthesis. It is also a representative of bioenergy grasses and a model for genetic study of invasive weeds. Despite having all traits of a model species, it is difficult to cross-pollinate because its flowering behavior is not well studied. We used time lapse digital recording to study the flowering time and pattern along a single panicle. We found that flowering in Setaria was triggered by the darkness of the night and when the temperature was lower than 35°C. The anthesis of all the spikelets in a panicle took up-to three nights flowering from 9:30 pm to 10:00 am in the morning. Each spikelet has three phases of anthesis during which pollination occurs. A spikelet remains open for less than three hours. The pollination time for each spikelet is less than 60 minutes. Information from this study will facilitate the geneticists and plant breeders to plan for efficient crossing of Setaria.

  18. A Modified Thermal Time Model Quantifying Germination Response to Temperature for C3 and C4 Species in Temperate Grassland

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    Hongxiang Zhang

    2015-07-01

    Full Text Available Thermal-based germination models are widely used to predict germination rate and germination timing of plants. However, comparison of model parameters between large numbers of species is rare. In this study, seeds of 27 species including 12 C4 and 15 C3 species were germinated at a range of constant temperatures from 5 °C to 40 °C. We used a modified thermal time model to calculate germination parameters at suboptimal temperatures. Generally, the optimal germination temperature was higher for C4 species than for C3 species. The thermal time constant for the 50% germination percentile was significantly higher for C3 than C4 species. The thermal time constant of perennials was significantly higher than that of annuals. However, differences in base temperatures were not significant between C3 and C4, or annuals and perennial species. The relationship between germination rate and seed mass depended on plant functional type and temperature, while the base temperature and thermal time constant of C3 and C4 species exhibited no significant relationship with seed mass. The results illustrate differences in germination characteristics between C3 and C4 species. Seed mass does not affect germination parameters, plant life cycle matters, however.

  19. Comparison of carbon balance in Mediterranean pilot constructed wetlands vegetated with different C4 plant species.

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    Barbera, Antonio C; Borin, Maurizio; Cirelli, Giuseppe L; Toscano, Attilio; Maucieri, Carmelo

    2015-02-01

    This study investigates carbon dioxide (CO2) and methane (CH4) emissions and carbon (C) budgets in a horizontal subsurface flow pilot-plant constructed wetland (CW) with beds vegetated with Cyperus papyrus L., Chrysopogon zizanioides (L.) Roberty, and Mischantus × giganteus Greef et Deu in the Mediterranean basin (Sicily) during the 1st year of plant growing season. At the end of the vegetative season, M. giganteus showed the higher biomass accumulation (7.4 kg m(-2)) followed by C. zizanioides (5.3 kg m(-2)) and C. papyrus (1.8 kg m(-2)). Significantly higher emissions of CO2 were detected in the summer, while CH4 emissions were maximum during spring. Cumulative CO2 emissions by C. papyrus and C. zizanioides during the monitoring period showed similar trends with final values of about 775 and 1,074 g m(-2), respectively, whereas M. giganteus emitted 3,395 g m(-2). Cumulative CH4 bed emission showed different trends for the three C4 plant species in which total gas release during the study period was for C. papyrus 12.0 g m(-2) and ten times higher for M. giganteus, while C. zizanioides bed showed the greatest CH4 cumulative emission with 240.3 g m(-2). The wastewater organic carbon abatement determined different C flux in the atmosphere. Gas fluxes were influenced both by plant species and monitored months with an average C-emitted-to-C-removed ratio for C. zizanioides, C. papyrus, and M. giganteus of 0.3, 0.5, and 0.9, respectively. The growing season C balances were positive for all vegetated beds with the highest C sequestered in the bed with M. giganteus (4.26 kg m(-2)) followed by C. zizanioides (3.78 kg m(-2)) and C. papyrus (1.89 kg m(-2)). To our knowledge, this is the first paper that presents preliminary results on CO2 and CH4 emissions from CWs vegetated with C4 plant species in Mediterranean basin during vegetative growth.

  20. Photosynthesis of C3 and C4 Species in Response to Increased CO2 Concentration and Drought Stress

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    HAMIM

    2005-12-01

    Full Text Available Photosynthetic gas exchange in response to increased carbon dioxide concentration ([CO2] and drought stress of two C3 (wheat and kale and two C4 species (Echinochloa crusgallii and Amaranthus caudatus were analysed. Plants were grown in controlled growth chambers with ambient (350 μmol mol−1 and doubled ambient [CO2]. Drought was given by withholding water until the plants severely wilted, whereas the control plants were watered daily. Even though stomatal conductance (Gs of C4 species either under ambient or double [CO2] was lower than those in C3, doubled [CO2] decreased Gs of all species under well watered conditions. As a result, the plants grown under doubled [CO2] transpired less water than those grown under ambient [CO2]. Photosynthesis (Pn of the C4 species was sustained during moderate drought when those of the C3 species decreased significantly. Doubled [CO2] increased photosynthesis of C3 but not of C4 species. Increased [CO2] was only able to delay Pn reduction of all species due to the drought, but not remove it completely. The positive effects of increased [CO2] during moderate drought and the disappearance of it under severe drought suggesting that metabolic effect may limit photosynthesis under severe drought.

  1. Photosynthesis of C3 and C4 Species in Response to Increased CO2 Concentration and Drought Stress

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    HAMIM

    2005-12-01

    Full Text Available Photosynthetic gas exchange in response to increased carbon dioxide concentration ([CO2] and drought stress of two C3 (wheat and kale and two C4 species (Echinochloa crusgallii and Amaranthus caudatus were analysed. Plants were grown in controlled growth chambers with ambient (350 mol mol-1 and doubled ambient [CO2]. Drought was given by withholding water until the plants severely wilted, whereas the control plants were watered daily. Even though stomatal conductance (Gs of C4 species either under ambient or double [CO2] was lower than those in C3, doubled [CO2] decreased Gs of all species under well watered conditions. As a result, the plants grown under doubled [CO2] transpired less water than those grown under ambient [CO2]. Photosynthesis (Pn of the C4 species was sustained during moderate drought when those of the C3 species decreased significantly. Doubled [CO2] increased photosynthesis of C3 but not of C4 species. Increased [CO2] was only able to delay Pn reduction of all species due to the drought, but not remove it completely. The positive effects of increased [CO2] during moderate drought and the disappearance of it under severe drought suggesting that metabolic effect may limit photosynthesis under severe drought.

  2. Isolation of dimorphic chloroplasts from the single-cell C4 species Bienertia sinuspersici

    Directory of Open Access Journals (Sweden)

    Lung Shiu-Cheung

    2012-03-01

    Full Text Available Abstract Three terrestrial plants are known to perform C4 photosynthesis without the dual-cell system by partitioning two distinct types of chloroplasts in separate cytoplasmic compartments. We report herein a protocol for isolating the dimorphic chloroplasts from Bienertia sinuspersici. Hypo-osmotically lysed protoplasts under our defined conditions released intact compartments containing the central chloroplasts and intact vacuoles with adhering peripheral chloroplasts. Following Percoll step gradient purification both chloroplast preparations demonstrated high homogeneities as evaluated from the relative abundance of respective protein markers. This protocol will open novel research directions toward understanding the mechanism of single-cell C4 photosynthesis.

  3. GRASS SPECIES FROM C-4 CARBON FIXATION GROUP: POLISH EXPERIMENT WITH A NOVEL ENERGY AND FORAGE PURPOSES CROP

    Directory of Open Access Journals (Sweden)

    Włodzimierz Majtkowski

    2010-02-01

    Full Text Available Experiment was conducted during four years 2003-2006. Materials used were three genus grass species of C-4 photosynthesis: Andropogon gerardi Vitman, Panicum virgatum L. and Miscanthus sacchariflorus (Maxim. Hack. Plants were planted at spring 1998. Agrotechnical part of experiment was conducted in Botanical Garden of Plant Breeding Acclimatization Institute in Bydgoszcz and analytical part in Department of Animal Nutrition and Feed Management, Faculty of Animal Breeding and Biology of University of Technology and Life Science in Bydgoszcz. Forage from grass C-4 photosynthesis were material of good ensilage suitability. High structural carbohydrates (NDF, ADF contents in tested forage dry matter suggest ensilage at early phases of plant development. Above results suggest to possibility of usage of forage from grass C-4 carbon fixation group for animal feeding purposes. C-4 grass forage should be recognized as a supplementary source of green matter in periods of insufficient access to traditional silage sources.

  4. Anatomy and ultrastructure of embryonic leaves of the C4 species Setaria viridis.

    Science.gov (United States)

    Junqueira, Nicia E G; Ortiz-Silva, Bianca; Leal-Costa, Marcos Vinícius; Alves-Ferreira, Márcio; Dickinson, Hugh G; Langdale, Jane A; Reinert, Fernanda

    2018-02-05

    Setaria viridis is being promoted as a model C4 photosynthetic plant because it has a small genome (~515 Mb), a short life cycle (~60 d) and it can be transformed. Unlike other C4 grasses such as maize, however, there is very little information about how C4 leaf anatomy (Kranz anatomy) develops in S. viridis. As a foundation for future developmental genetic studies, we provide an anatomical and ultrastructural framework of early shoot development in S. viridis, focusing on the initiation of Kranz anatomy in seed leaves. Setaria viridis seeds were germinated and divided into five stages covering development from the dry seed (stage S0) to 36 h after germination (stage S4). Material at each of these stages was examined using conventional light, scanning and transmission electron microscopy. Dry seeds contained three embryonic leaf primordia at different developmental stages (plastochron 1-3 primordia). The oldest (P3) leaf primordium possessed several procambial centres whereas P2 displayed only ground meristem. At the tip of P3 primordia at stage S4, C4 leaf anatomy typical of the malate dehydrogenase-dependent nicotinamide dinucleotide phosphate (NADP-ME) subtype was evident in that vascular bundles lacked a mestome layer and were surrounded by a single layer of bundle sheath cells that contained large, centrifugally located chloroplasts. Two to three mesophyll cells separated adjacent vascular bundles and one mesophyll cell layer on each of the abaxial and adaxial sides delimited vascular bundles from the epidermis. The morphological trajectory reported here provides a foundation for studies of gene regulation during early leaf development in S. viridis and a framework for comparative analyses with other C4 grasses.

  5. Initial Events during the Evolution of C4 Photosynthesis in C3 Species of Flaveria1[W][OPEN

    Science.gov (United States)

    Sage, Tammy L.; Busch, Florian A.; Johnson, Daniel C.; Friesen, Patrick C.; Stinson, Corey R.; Stata, Matt; Sultmanis, Stefanie; Rahman, Beshar A.; Rawsthorne, Stephen; Sage, Rowan F.

    2013-01-01

    The evolution of C4 photosynthesis in many taxa involves the establishment of a two-celled photorespiratory CO2 pump, termed C2 photosynthesis. How C3 species evolved C2 metabolism is critical to understanding the initial phases of C4 plant evolution. To evaluate early events in C4 evolution, we compared leaf anatomy, ultrastructure, and gas-exchange responses of closely related C3 and C2 species of Flaveria, a model genus for C4 evolution. We hypothesized that Flaveria pringlei and Flaveria robusta, two C3 species that are most closely related to the C2 Flaveria species, would show rudimentary characteristics of C2 physiology. Compared with less-related C3 species, bundle sheath (BS) cells of F. pringlei and F. robusta had more mitochondria and chloroplasts, larger mitochondria, and proportionally more of these organelles located along the inner cell periphery. These patterns were similar, although generally less in magnitude, than those observed in the C2 species Flaveria angustifolia and Flaveria sonorensis. In F. pringlei and F. robusta, the CO2 compensation point of photosynthesis was slightly lower than in the less-related C3 species, indicating an increase in photosynthetic efficiency. This could occur because of enhanced refixation of photorespired CO2 by the centripetally positioned organelles in the BS cells. If the phylogenetic positions of F. pringlei and F. robusta reflect ancestral states, these results support a hypothesis that increased numbers of centripetally located organelles initiated a metabolic scavenging of photorespired CO2 within the BS. This could have facilitated the formation of a glycine shuttle between mesophyll and BS cells that characterizes C2 photosynthesis. PMID:24064930

  6. The effects of salinity on photosynthesis and growth of the single-cell C4 species Bienertia sinuspersici (Chenopodiaceae).

    Science.gov (United States)

    Leisner, Courtney P; Cousins, Asaph B; Offermann, Sascha; Okita, Thomas W; Edwards, Gerald E

    2010-12-01

    Recent research on the photosynthetic mechanisms of plant species in the Chenopodiaceae family revealed that three species, including Bienertia sinuspersici, can carry out C(4) photosynthesis within individual photosynthetic cells, through the development of two cytoplasmic domains having dimorphic chloroplasts. These unusual single-cell C(4) species grow in semi-arid saline conditions and have semi-terete succulent leaves. The effects of salinity on growth and photosynthesis of B. sinuspersici were studied. The results show that NaCl is not required for development of the single-cell C(4) system. There is a large enhancement of growth in culture with 50-200 mM NaCl, while there is severe inhibition at 400 mM NaCl. With increasing salinity, the carbon isotope values (δ(13)C) of leaves increased from -17.3(o)/(oo) (C(4)-like) without NaCl to -14.6(o)/(oo) (C(4)) with 200 mM NaCl, possibly due to increased capture of CO(2) from the C(4) cycle by Rubisco and reduced leakiness. Compared to growth without NaCl, leaves of plants grown under saline conditions were much larger (~2 fold) and more succulent, and the leaf solute levels increased up to ~2000 mmol kg solvent(-1). Photosynthesis on an incident leaf area basis (CO(2) saturated rates, and carboxylation efficiency under limiting CO(2)) and stomatal conductance declined with increasing salinity. On a leaf area basis, there was some decline in Rubisco content with increasing salinity up to 200 mM NaCl, but there was a marked increase in the levels of pyruvate, Pi dikinase, and phosphoenolpyruvate carboxylase (possibly in response to sensitivity of these enzymes and C(4) cycle function to increasing salinity). The decline in photosynthesis on a leaf area basis was compensated for on a per leaf basis, up to 200 mM NaCl, by the increase in leaf size. The influence of salinity on plant development and the C(4) system in Bienertia is discussed.

  7. Comparative gas exchange and growth responses of C3 and C4 beach species grown at different salinities.

    Science.gov (United States)

    De Jong, T M

    1978-01-01

    Comparative laboratory gas exchange and relative growth rate experiments were conducted on three native California coastal strand species at four salinity treatment levels. Relative mesophyll conductance sensitivities to salinity of Atriplex leucophylla (Moq.) D. Dietr. (C4) and Atriplex californica Moq. in D.C. (C3) were nearly identical. Mesophyll conductances of both species were stimulated by moderate levels of salinity. Mesophyll conductances of Abronia maritima Nutt. ex Wats. (C3) were highest in the absence of salinity and depressed by increasing levels of salinity. Increasing levels of salinity generally decreased net photosynthesis and leaf conductances but increased water use efficiencies. The C4 species, Atriplex leucophylla, had higher mesophyll conductances and water use efficiencies at all salinity levels than the C3 species. The effects of salinity on relative growth and net assimilation rates of greenhouse grown plants were not directly correlated with the effects on net photosynthesis measured in the laboratory. Growth of Abronia maritima was greatly stimulated by low levels of salinity whereas photosynthesis was substantially inhibited. The possible significance of C4 photosynthesis in relation to salinity is discussed.

  8. Optimizing spectral resolutions for the classification of C3 and C4 grass species, using wavelengths of known absorption features

    Science.gov (United States)

    Adjorlolo, Clement; Cho, Moses A.; Mutanga, Onisimo; Ismail, Riyad

    2012-01-01

    Hyperspectral remote-sensing approaches are suitable for detection of the differences in 3-carbon (C3) and four carbon (C4) grass species phenology and composition. However, the application of hyperspectral sensors to vegetation has been hampered by high-dimensionality, spectral redundancy, and multicollinearity problems. In this experiment, resampling of hyperspectral data to wider wavelength intervals, around a few band-centers, sensitive to the biophysical and biochemical properties of C3 or C4 grass species is proposed. The approach accounts for an inherent property of vegetation spectral response: the asymmetrical nature of the inter-band correlations between a waveband and its shorter- and longer-wavelength neighbors. It involves constructing a curve of weighting threshold of correlation (Pearson's r) between a chosen band-center and its neighbors, as a function of wavelength. In addition, data were resampled to some multispectral sensors-ASTER, GeoEye-1, IKONOS, QuickBird, RapidEye, SPOT 5, and WorldView-2 satellites-for comparative purposes, with the proposed method. The resulting datasets were analyzed, using the random forest algorithm. The proposed resampling method achieved improved classification accuracy (κ=0.82), compared to the resampled multispectral datasets (κ=0.78, 0.65, 0.62, 0.59, 0.65, 0.62, 0.76, respectively). Overall, results from this study demonstrated that spectral resolutions for C3 and C4 grasses can be optimized and controlled for high dimensionality and multicollinearity problems, yet yielding high classification accuracies. The findings also provide a sound basis for programming wavebands for future sensors.

  9. A developing Setaria viridis internode: an experimental system for the study of biomass generation in a C4 model species.

    Science.gov (United States)

    Martin, Antony P; Palmer, William M; Brown, Christopher; Abel, Christin; Lunn, John E; Furbank, Robert T; Grof, Christopher P L

    2016-01-01

    Recently, there has been interest in establishing a monocot C4 model species with a small genome, short lifecycle, and capacity for genetic transformation. Setaria viridis has been adopted to fill this role, since reports of Agrobacterium-mediated transformation in 2010, and sequencing of its genome in 2012. To date, S. viridis has primarily been used to further our understanding of C4 photosynthesis, but is also an ideal system for the study of biomass crops, which are almost exclusively C4 panicoid grasses. Biogenesis of stem tissue, its cell wall composition, and soluble sugar content are important determinants of bioenergy crop yields. Here we show that a developing S. viridis internode is a valuable experimental system for gene discovery in relation to these important bioenergy feedstock traits. The rate of maximal stem biomass accumulation in S. viridis A10 under long day growth was at the half-head emergence developmental stage. At this stage of development, internode 5 (of 7) was found to be rapidly expanding with an active meristem, a zone of cell expansion (primary cell walls), a transitional zone where cell expansion ceased and secondary cell wall deposition was initiated, and a mature zone that was actively accumulating soluble sugars. A simple method for identifying these zones was established allowing rapid dissection and snap-freezing for RNAseq analysis. A transcriptome profile was generated for each zone showing a transition from cell division and nucleic acid synthesis/processing in the meristem, to metabolism, energy synthesis, and primary cell wall synthesis in the cell expansion zone, to secondary cell wall synthesis in the transitional zone, to sugar transport, and photosynthesis in the mature zone. The identification of these zones has provided a valuable experimental system for investigating key bioenergy traits, including meristematic activity, cell wall biosynthesis, and soluble sugar accumulation, in a C4 panicoid grass that has genetic

  10. C2 photosynthesis generates about 3-fold elevated leaf CO2 levels in the C3–C4 intermediate species Flaveria pubescens

    OpenAIRE

    Keerberg, Olav; Pärnik, Tiit; Ivanova, Hiie; Bassüner, Burgund; Bauwe, Hermann

    2014-01-01

    Formation of a photorespiration-based CO2-concentrating mechanism in C3–C4 intermediate plants is seen as a prerequisite for the evolution of C4 photosynthesis, but it is not known how efficient this mechanism is. Here, using in vivo Rubisco carboxylation-to-oxygenation ratios as a proxy to assess relative intraplastidial CO2 levels is suggested. Such ratios were determined for the C3–C4 intermediate species Flaveria pubescens compared with the closely related C3 plant F. cronquistii and the ...

  11. C2 photosynthesis generates about 3-fold elevated leaf CO2 levels in the C3-C4 intermediate species Flaveria pubescens.

    Science.gov (United States)

    Keerberg, Olav; Pärnik, Tiit; Ivanova, Hiie; Bassüner, Burgund; Bauwe, Hermann

    2014-07-01

    Formation of a photorespiration-based CO2-concentrating mechanism in C3-C4 intermediate plants is seen as a prerequisite for the evolution of C4 photosynthesis, but it is not known how efficient this mechanism is. Here, using in vivo Rubisco carboxylation-to-oxygenation ratios as a proxy to assess relative intraplastidial CO2 levels is suggested. Such ratios were determined for the C3-C4 intermediate species Flaveria pubescens compared with the closely related C3 plant F. cronquistii and the C4 plant F. trinervia. To this end, a model was developed to describe the major carbon fluxes and metabolite pools involved in photosynthetic-photorespiratory carbon metabolism and used quantitatively to evaluate the labelling kinetics during short-term (14)CO2 incorporation. Our data suggest that the photorespiratory CO2 pump elevates the intraplastidial CO2 concentration about 3-fold in leaves of the C3-C4 intermediate species F. pubescens relative to the C3 species F. cronquistii. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  12. C2 photosynthesis generates about 3-fold elevated leaf CO2 levels in the C3–C4 intermediate species Flaveria pubescens

    Science.gov (United States)

    Keerberg, Olav; Pärnik, Tiit; Ivanova, Hiie; Bassüner, Burgund; Bauwe, Hermann

    2014-01-01

    Formation of a photorespiration-based CO2-concentrating mechanism in C3–C4 intermediate plants is seen as a prerequisite for the evolution of C4 photosynthesis, but it is not known how efficient this mechanism is. Here, using in vivo Rubisco carboxylation-to-oxygenation ratios as a proxy to assess relative intraplastidial CO2 levels is suggested. Such ratios were determined for the C3–C4 intermediate species Flaveria pubescens compared with the closely related C3 plant F. cronquistii and the C4 plant F. trinervia. To this end, a model was developed to describe the major carbon fluxes and metabolite pools involved in photosynthetic–photorespiratory carbon metabolism and used quantitatively to evaluate the labelling kinetics during short-term 14CO2 incorporation. Our data suggest that the photorespiratory CO2 pump elevates the intraplastidial CO2 concentration about 3-fold in leaves of the C3–C4 intermediate species F. pubescens relative to the C3 species F. cronquistii. PMID:24916069

  13. Seasonal and inter-annual photosynthetic response of representative C4 species to soil water content and leaf nitrogen concentration across a tropical seasonal floodplain

    NARCIS (Netherlands)

    Mantlana, K.B.; Arneth, A.; Veenendaal, E.M.; Wohland, P.; Wolski, P.; Kolle, O.; Lloyd, J.

    2008-01-01

    We examined the seasonal and inter-annual variation of leaf-level photosynthetic characteristics of three C4 perennial species, Cyperus articulatus, Panicum repens and Imperata cylindrica, and their response to environmental variables, to determine comparative physiological responses of plants

  14. Identification and characterization of miRNAs in two closely related C4 and C3 species of Cleome by high-throughput sequencing.

    Science.gov (United States)

    Gao, Shuangcheng; Zhao, Wei; Li, Xiang; You, Qingbo; Shen, Xinjie; Guo, Wei; Wang, Shihua; Shi, Guoan; Liu, Zheng; Jiao, Yongqing

    2017-04-19

    Cleome gynandra and Cleome hassleriana, which are C4 and C3 plants, respectively, are two species of Cleome. The close genetic relationship between C. gynandra and C. hassleriana provides advantages for discovering the differences in leaf development and physiological processes between C3 and C4 plants. MicroRNAs (miRNAs) are a class of important regulators of various biological processes. In this study, we investigate the differences in the characteristics of miRNAs between C. gynandra and C. hassleriana using high-throughput sequencing technology. In total, 94 and 102 known miRNAs were identified in C. gynandra and C. hassleriana, respectively, of which 3 were specific for C. gynandra and 10 were specific for C. hassleriana. Ninety-one common miRNAs were identified in both species. In addition, 4 novel miRNAs were detected, including three in C. gynandra and three in C. hassleriana. Of these miRNAs, 67 were significantly differentially expressed between these two species and were involved in extensive biological processes, such as glycol-metabolism and photosynthesis. Our study not only provided resources for C. gynandra and C. hassleriana research but also provided useful clues for the understanding of the roles of miRNAs in the alterations of biological processes in leaf tissues during the evolution of the C4 pathway.

  15. Adaptation of C4 bioenergy crop species to various environments within the Southern Great Plains of U.S.

    Science.gov (United States)

    As high productivities of perennial grasses are evaluated for feedstock, a major consideration is biomass stability. In this study, two experiments were conducted to examine some components of this for two biofuel species: switchgrass (Panicum vigratum L.) and Miscanthus x giganteus (Mxg). The po...

  16. Examining the strength of the newly-launched Sentinel 2 MSI sensor in detecting and discriminating subtle differences between C3 and C4 grass species

    Science.gov (United States)

    Shoko, C.; Mutanga, O.

    2017-07-01

    C3 and C4 grass species discrimination has increasingly become relevant in understanding their response to environmental changes and to monitor their integrity in providing goods and services. While remotely-sensed data provide robust, cost-effective and repeatable monitoring tools for C3 and C4 grasses, this has been largely limited by the scarcity of sensors with better earth imaging characteristics. The recent launch of the advanced Sentinel 2 MultiSpectral Instrument (MSI) presents a new prospect for discriminating C3 and C4 grasses. The present study tested the potential of Sentinel 2, characterized by refined spatial resolution and more unique spectral bands in discriminating between Festuca (C3) and Themeda (C4) grasses. To evaluate the performance of Sentinel 2 MSI; spectral bands, vegetation indices and spectral bands plus indices were used. Findings from Sentinel 2 were compared with those derived from the widely-used Worldview 2 commercial sensor and the Landsat 8 Operational Land Imager (OLI). Overall classification accuracies have shown that Sentinel 2 bands have potential (90.36%), than indices (85.54%) and combined variables (88.61%). The results were comparable to Worldview 2 sensor, which produced slightly higher accuracies using spectral bands (95.69%), indices (86.02%) and combined variables (87.09%), and better than Landsat 8 OLI spectral bands (75.26%), indices (82.79%) and combined variables (86.02%). Sentinel 2 bands produced lower errors of commission and omission (between 4.76 and 14.63%), comparable to Worldview 2 (between 1.96 and 7.14%), than Landsat 8 (between 18.18 and 30.61%), when classifying the two species. The classification accuracy from Sentinel 2 also did not differ significantly (z = 1.34) from Worldview 2, using standard bands; it was significantly (z > 1.96) different using indices and combined variables, whereas when compared to Landsat 8, Sentinel 2 accuracies were significantly different (z > 1.96) using all variables

  17. Diurnal and Seasonal Variation in the Carbon Isotope Composition of Leaf- and Root- respired CO2 in C3 and C4 Species

    Science.gov (United States)

    Sun, W.; Resco, V.; Chen, S.; Williams, D. G.

    2008-12-01

    The carbon isotope signature of leaf (δ13Cl) and root (δ13Cr) dark- respired CO2 records and integrates short-term metabolic changes. Plants with C3 and C4 photosynthetic metabolism are expected to differ in diurnal and seasonal patterns in δ13Cl and δ13Cr because of differences in photorespiration, isotopic fractionation at metabolic branch points and allocation patterns. A thorough understanding of the environmental and metabolic controls on δ13Cl and δ13Cr is necessary to interpret the δ13C of ecosystem respired CO2 and partition the CO2 efflux into autotrophic and heterotrophic respiration sources. We measured δ13Cl in two C3 tree species (Prosopis velutina and Celtis reticulata), a C3 herb (Viguiera dentata) and a C4 grass (Sporobolus wrightii), and δ13Cr in P. velutina and S. wrightii in a semiarid savanna in southeastern Arizona, USA. δ13Cl during the dry pre-monsoon period was relatively enriched in 13C during daytime periods and became depleted in 13C at night relative to daytime values for all species with the exception of S. wrightii, the C4 grass. δ13Cl in S. wrightii was strongly influenced by seasonal differences in water availability with a larger diurnal amplitude in δ13Cl (8.2 +/- 0.6‰) during the wet monsoon period compared to that in the dry pre-monsoon period (4.4 +/- 0.4‰). The δ13C values of starch and lipid fractions remained constant over diurnal periods within the pre-monsoon and monsoon seasons. For C3 species, δ13Cl and δ13C of the cumulative, flux-weighted photosynthate pool estimated from gas exchange were strongly positively correlated, suggesting that progressive 13C-enrichment of leaf-respired CO2 during the daytime period resulted from changes in the δ13C signature of respiratory substrates associated with short-term changes in photosynthetic 13C discrimination. Rapid decreases in δ13Cl following the daytime period was likely caused by decreases in the ratio of PDH:acetyl-CoA oxidation rather than by a shift in

  18. [C4 type photosynthesis].

    Science.gov (United States)

    Drozak, Anna; Wasilewska, Wioleta; Buczyńska, Alicja; Romanowska, Elzbieta

    2012-01-01

    C4 photosynthesis includes several anatomical and biochemical modifications that allow plants to concentrate CO2 at the site of Rubisco. The photorespiratory pathway is repressed in C4 plants, since the rates of photosynthesis and biomass production are increased. This is an adaptation to high light intensities, high temperatures and dryness. C4 plants contain two distinct types of photosynthetic cells, mesophyll and bundle sheath. The processes of assimilation and reduction of CO2 are separated spatiality and catayzed by two different enzymes. Only the bundle sheath chloroplasts perform the reactions of the Calvin-Benson cycle with the help of the Rubisco enzyme present exclusively in this cell type. The primary CO2 fixation occurs in mesophyll cells through the action of the phosphoenolpyruvate carboxylase. The light-dependent reactions of the photosynthesis occur exclusively in the latter cell type. These differences in photochemistry lead to distinct redox profiles in both types of cells. C4 plants are divided into three biochemical subtypes on the basis of differences in the mechanisms of decarboxylation of the C4 acids. C4 plants will provide the main source of food for humans and animals in the nearest decade.

  19. Species-dependent partitioning of C and N stable isotopes between arbuscular mycorrhizal fungi and their C3 and C4 hosts

    Czech Academy of Sciences Publication Activity Database

    Courty, P.-E.; Doubková, Pavla; Calabrese, S.; Niemann, H.; Lehmann, M. F.; Vosátka, Miroslav; Selosse,, M.-A.

    2015-01-01

    Roč. 82, Mar 2015 (2015), s. 52-61 ISSN 0038-0717 Institutional support: RVO:67985939 Keywords : arbuscular mycorrhizal symbiosis * carbon and nitrogen stable isotopes * C3 and C4 plants Subject RIV: EF - Botanics Impact factor: 4.152, year: 2015

  20. Comparative proteomic analysis of the stolon cold stress response between the C4 perennial grass species Zoysia japonica and Zoysia metrella.

    Directory of Open Access Journals (Sweden)

    Jiping Xuan

    Full Text Available Zoysiagrass, the most cold-tolerant grass among the warm-season turfgrasses, is often used as a model species for isolating cellular components related to cold stress. To understand the proteomic responses to cold stress in zoysiagrass stolons, we extracted stolon proteins from Zoysiajaponica, cv. Meyer (cold-tolerant and Z. metrella, cv. Diamond (cold-sensitive, which were grown with or without cold treatment. Approximately 700 proteins were resolved on 2-DE gels, and 70 protein spots were differentially accumulated. We further observed that 45 of the identified proteins participate in 10 metabolic pathways and cellular processes. A significantly greater number of proteins accumulated in the Meyer than in the Diamond and 15 increased proteins were detected only in the Meyer cultivar under cold stress. Furthermore, we propose a cold stress-responsive protein network composed of several different functional components that exhibits a balance between reactive oxygen species (ROS production and scavenging, accelerated protein biosynthesis and proteolysis, reduced protein folding, enhanced photosynthesis, abundant energy supply and enhanced biosynthesis of carbohydrates and nucleotides. Generally, the cold-tolerant Meyer cultivar showed a greater ROS scavenging ability, more abundant energy supply and increased photosynthesis and protein synthesis than did the cold-sensitive Diamond cultivar, which may partly explain why Meyer is more cold tolerant.

  1. Photosynthesis of C3, C3-C4, and C4 grasses at glacial CO2.

    Science.gov (United States)

    Pinto, Harshini; Sharwood, Robert E; Tissue, David T; Ghannoum, Oula

    2014-07-01

    Most physiology comparisons of C3 and C4 plants are made under current or elevated concentrations of atmospheric CO2 which do not reflect the low CO2 environment under which C4 photosynthesis has evolved. Accordingly, photosynthetic nitrogen (PNUE) and water (PWUE) use efficiency, and the activity of the photosynthetic carboxylases [Rubisco and phosphoenolpyruvate carboxylase (PEPC)] and decarboxylases [NADP-malic enzyme (NADP-ME) and phosphoenolpyruvate carboxykinase (PEP-CK)] were compared in eight C4 grasses with NAD-ME, PCK, and NADP-ME subtypes, one C3 grass, and one C3-C4 grass grown under ambient (400 μl l(-1)) and glacial (180 μl l(-1)) CO2. Glacial CO2 caused a smaller reduction of photosynthesis and a greater increase of stomatal conductance in C4 relative to C3 and C3-C4 species. Panicum bisulcatum (C3) acclimated to glacial [CO2] by doubling Rubisco activity, while Rubisco was unchanged in Panicum milioides (C3-C4), possibly due to its high leaf N and Rubisco contents. Glacial CO2 up-regulated Rubisco and PEPC activities in concert for several C4 grasses, while NADP-ME and PEP-CK activities were unchanged, reflecting the high control exerted by the carboxylases relative to the decarboxylases on the efficiency of C4 metabolism. Despite having larger stomatal conductance at glacial CO2, C4 species maintained greater PWUE and PNUE relative to C3-C4 and C3 species due to higher photosynthetic rates. Relative to other C4 subtypes, NAD-ME and PEP-CK grasses had the highest PWUE and PNUE, respectively; relative to C3, the C3-C4 grass had higher PWUE and similar PNUE at glacial CO2. Biomass accumulation was reduced by glacial CO2 in the C3 grass relative to the C3-C4 grass, while biomass was less reduced in NAD-ME grasses compared with NADP-ME and PCK grasses. Under glacial CO2, high resource use efficiency offers a key evolutionary advantage for the transition from C3 to C4 photosynthesis in water- and nutrient-limited environments. © The Author 2014

  2. Strategies for improving C4 photosynthesis.

    Science.gov (United States)

    von Caemmerer, Susanne; Furbank, Robert T

    2016-06-01

    Recent activities to improve photosynthetic performance in crop plants has focused mainly on C3 photosynthesis where there are clear identified targets such as improving Rubisco kinetics, installation of a CO2 concentrating mechanism and alleviating limitations in chloroplast electron transport. Here we address strategies to improve photosynthetic performance in C4 plants, which utilize a CO2 concentrating mechanism, having evolved a complex blend of anatomy and biochemistry to achieve this. While the limitations to photosynthetic flux are not as well studied in C4 plants, work in transgenic Flaveria bidentis, a transformable model C4 dicot, and recent transcriptional analysis of leaves from diverse C4 plants, provides several gene candidates for improvement of carbon metabolism (such as pyruvate orthophosphate dikinase, phosphoenolpyruvate carboxylase and Rubisco) and for access of CO2 to phosphoenolpyruvate carboxylase in the mesophyll cells (such as carbonic anhydrase and CO2 porins). Chloroplast electron transport in C4 plants is shared between the two cell types, providing opportunities not only to alleviate limitations to flux through intersystem electron transport by targeting nuclear encoded proteins in the cytochrome (Cyt) b6/f complex, but in better sharing the harvesting of light energy between mesophyll and bundle sheath chloroplasts. Gene candidates for improvement of C4 photosynthesis could be utilized either through transgenic approaches or via mining natural allelic variation in sequenced populations of crop species. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Rubisco gene expression in C4 plants.

    Science.gov (United States)

    Patel, Minesh; Berry, James O

    2008-01-01

    In leaves of most C(4) plants, ribulose 1,5 bisphosphate carboxylase (Rubisco) accumulates only in bundle sheath (bs) cells that surround the vascular centres, and not in mesophyll (mp) cells. It has been shown previously that in the C(4) dicots amaranth and Flaveria bidentis, post-transcriptional control of mRNA translation and stability mediate the C(4) expression patterns of genes encoding the large and small Rubisco subunits (chloroplast rbcL and nuclear RbcS, respectively). Translational control appears to regulate bs cell-specific Rubisco gene expression during early dicot leaf development, while control of mRNA stability appears to mediate bs-specific accumulation of RbcS and rbcL transcripts in mature leaves. Post-transcriptional control is also involved in the regulation of Rubisco gene expression by light, and in response to photosynthetic activity. Transgenic and transient expression studies in F. bidentis provide direct evidence for post-transcriptional control of bs cell-specific RbcS expression, which is mediated by the 5' and 3' untranslated regions (UTRs) of the mRNA. Comparisons of Rubisco gene expression in these dicots and in the monocot maize indicates possible commonalities in the regulation of RbcS and rbcL genes in these divergent C(4) species. Now that the role of post-transcriptional regulation in C(4) gene expression has been established, it is likely that future studies of mRNA-protein interactions will address long-standing questions about the establishment and maintenance of cell type-specificity in these plants. Some of these regulatory mechanisms may have ancestral origins in C(3) species, through modification of pre-existing factors, or by the acquisition of novel C(4) processes.

  4. Balanced {C_4, C_5}-Quatrefoil Systems

    OpenAIRE

    Ushio, Kazuhiko

    2004-01-01

    In graph theory, the decomposition problems of graphs are very important topics. Various types of decompositions of many graphs can be seen in the literature of gaph theory. We give the necessary and sufficient condition for the existence of a balanced {C_4, C_5}-quatrefoil decomposition of K_n for each of (C_4, C_4, C_4, C_4)-quatrefoil, (C_4, C_4, C_4, C_5)-quatrefoil, (C_4, C_4, C_5, C_5)-quatrefoil, (C_4, C_5, C_5, C_5)-quatrefoil, and (C_5, C_5, C_5, C_5)-quatrefoil. These decompositions...

  5. From proto-Kranz to C4 Kranz: building the bridge to C4 photosynthesis.

    Science.gov (United States)

    Sage, Rowan F; Khoshravesh, Roxana; Sage, Tammy L

    2014-07-01

    In this review, we examine how the specialized "Kranz" anatomy of C4 photosynthesis evolved from C3 ancestors. Kranz anatomy refers to the wreath-like structural traits that compartmentalize the biochemistry of C4 photosynthesis and enables the concentration of CO2 around Rubisco. A simplified version of Kranz anatomy is also present in the species that utilize C2 photosynthesis, where a photorespiratory glycine shuttle concentrates CO2 into an inner bundle-sheath-like compartment surrounding the vascular tissue. C2 Kranz is considered to be an intermediate stage in the evolutionary development of C4 Kranz, based on the intermediate branching position of C2 species in 14 evolutionary lineages of C4 photosynthesis. In the best-supported model of C4 evolution, Kranz anatomy in C2 species evolved from C3 ancestors with enlarged bundle sheath cells and high vein density. Four independent lineages have been identified where C3 sister species of C2 plants exhibit an increase in organelle numbers in the bundle sheath and enlarged bundle sheath cells. Notably, in all of these species, there is a pronounced shift of mitochondria to the inner bundle sheath wall, forming an incipient version of the C2 type of Kranz anatomy. This incipient version of C2 Kranz anatomy is termed proto-Kranz, and is proposed to scavenge photorespiratory CO2. By doing so, it may provide fitness benefits in hot environments, and thus represent a critical first stage of the evolution of both the C2 and C4 forms of Kranz anatomy. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  6. C4 bioenergy crops for cool climates, with special emphasis on perennial C4 grasses.

    Science.gov (United States)

    Sage, Rowan F; de Melo Peixoto, Murilo; Friesen, Patrick; Deen, Bill

    2015-07-01

    There is much interest in cultivating C4 perennial plants in northern climates where there is an abundance of land and a potential large market for biofuels. C4 feedstocks can exhibit superior yields to C3 alternatives during the long warm days of summer at high latitude, but their summer success depends on an ability to tolerate deep winter cold, spring frosts, and early growth-season chill. Here, we review cold tolerance limits in C4 perennial grasses. Dozens of C4 species are known from high latitudes to 63 °N and elevations up to 5200 m, demonstrating that C4 plants can adapt to cold climates. Of the three leading C4 grasses being considered for bioenergy production in cold climates--Miscanthus spp., switchgrass (Panicum virgatum), and prairie cordgrass (Spartina pectinata)--all are tolerant of cool temperatures (10-15 °C), but only cordgrass tolerates hard spring frosts. All three species overwinter as dormant rhizomes. In the productive Miscanthus×giganteus hybrids, exposure to temperatures below -3 °C to -7 °C will kill overwintering rhizomes, while for upland switchgrass and cordgrass, rhizomes survive exposure to temperatures above -20 °C to -24 °C. Cordgrass emerges earlier than switchgrass and M. giganteus genotypes, but lacks the Miscanthus growth potential once warmer days of late spring arrive. To enable C4-based bioenergy production in colder climates, breeding priorities should emphasize improved cold tolerance of M.×giganteus, and enhanced productivity of switchgrass and cordgrass. This should be feasible in the near future, because wild populations of each species exhibit a diverse range of cold tolerance and growth capabilities. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  7. Photosynthesis of C3, C3–C4, and C4 grasses at glacial CO2

    Science.gov (United States)

    Pinto, Harshini; Sharwood, Robert E.; Tissue, David T.; Ghannoum, Oula

    2014-01-01

    Most physiology comparisons of C3 and C4 plants are made under current or elevated concentrations of atmospheric CO2 which do not reflect the low CO2 environment under which C4 photosynthesis has evolved. Accordingly, photosynthetic nitrogen (PNUE) and water (PWUE) use efficiency, and the activity of the photosynthetic carboxylases [Rubisco and phosphoenolpyruvate carboxylase (PEPC)] and decarboxylases [NADP-malic enzyme (NADP-ME) and phosphoenolpyruvate carboxykinase (PEP-CK)] were compared in eight C4 grasses with NAD-ME, PCK, and NADP-ME subtypes, one C3 grass, and one C3–C4 grass grown under ambient (400 μl l–1) and glacial (180 μl l–1) CO2. Glacial CO2 caused a smaller reduction of photosynthesis and a greater increase of stomatal conductance in C4 relative to C3 and C3–C4 species. Panicum bisulcatum (C3) acclimated to glacial [CO2] by doubling Rubisco activity, while Rubisco was unchanged in Panicum milioides (C3–C4), possibly due to its high leaf N and Rubisco contents. Glacial CO2 up-regulated Rubisco and PEPC activities in concert for several C4 grasses, while NADP-ME and PEP-CK activities were unchanged, reflecting the high control exerted by the carboxylases relative to the decarboxylases on the efficiency of C4 metabolism. Despite having larger stomatal conductance at glacial CO2, C4 species maintained greater PWUE and PNUE relative to C3–C4 and C3 species due to higher photosynthetic rates. Relative to other C4 subtypes, NAD-ME and PEP-CK grasses had the highest PWUE and PNUE, respectively; relative to C3, the C3–C4 grass had higher PWUE and similar PNUE at glacial CO2. Biomass accumulation was reduced by glacial CO2 in the C3 grass relative to the C3–C4 grass, while biomass was less reduced in NAD-ME grasses compared with NADP-ME and PCK grasses. Under glacial CO2, high resource use efficiency offers a key evolutionary advantage for the transition from C3 to C4 photosynthesis in water- and nutrient-limited environments. PMID:24723409

  8. C4GEM, a Genome-Scale Metabolic Model to Study C4 Plant Metabolism1[W][OA

    Science.gov (United States)

    de Oliveira Dal’Molin, Cristiana Gomes; Quek, Lake-Ee; Palfreyman, Robin William; Brumbley, Stevens Michael; Nielsen, Lars Keld

    2010-01-01

    Leaves of C4 grasses (such as maize [Zea mays], sugarcane [Saccharum officinarum], and sorghum [Sorghum bicolor]) form a classical Kranz leaf anatomy. Unlike C3 plants, where photosynthetic CO2 fixation proceeds in the mesophyll (M), the fixation process in C4 plants is distributed between two cell types, the M cell and the bundle sheath (BS) cell. Here, we develop a C4 genome-scale model (C4GEM) for the investigation of flux distribution in M and BS cells during C4 photosynthesis. C4GEM, to our knowledge, is the first large-scale metabolic model that encapsulates metabolic interactions between two different cell types. C4GEM is based on the Arabidopsis (Arabidopsis thaliana) model (AraGEM) but has been extended by adding reactions and transporters responsible to represent three different C4 subtypes (NADP-ME [for malic enzyme], NAD-ME, and phosphoenolpyruvate carboxykinase). C4GEM has been validated for its ability to synthesize 47 biomass components and consists of 1,588 unique reactions, 1,755 metabolites, 83 interorganelle transporters, and 29 external transporters (including transport through plasmodesmata). Reactions in the common C4 model have been associated with well-annotated C4 species (NADP-ME subtypes): 3,557 genes in sorghum, 11,623 genes in maize, and 3,881 genes in sugarcane. The number of essential reactions not assigned to genes is 131, 135, and 156 in sorghum, maize, and sugarcane, respectively. Flux balance analysis was used to assess the metabolic activity in M and BS cells during C4 photosynthesis. Our simulations were consistent with chloroplast proteomic studies, and C4GEM predicted the classical C4 photosynthesis pathway and its major effect in organelle function in M and BS. The model also highlights differences in metabolic activities around photosystem I and photosystem II for three different C4 subtypes. Effects of CO2 leakage were also explored. C4GEM is a viable framework for in silico analysis of cell cooperation between M and BS

  9. Drought constraints on C4 photosynthesis: stomatal and metabolic limitations in C3 and C4 subspecies of Alloteropsis semialata.

    Science.gov (United States)

    Ripley, Brad S; Gilbert, Matthew E; Ibrahim, Douglas G; Osborne, Colin P

    2007-01-01

    The C4 photosynthetic pathway uses water more efficiently than the C3 type, yet biogeographical analyses show a decline in C4 species relative to C3 species with decreasing rainfall. To investigate this paradox, the hypothesis that the C4 advantage over C3 photosynthesis is diminished by drought was tested, and the underlying stomatal and metabolic mechanisms of this response determined. The effects of drought and high evaporative demand on leaf gas exchange and photosynthetic electron sinks in C3 and C4 subspecies of the grass Alloteropsis semialata were examined. Plant responses to climatic variation and soil drought were investigated using a common garden experiment with well-watered and natural rainfall treatments, and underlying mechanisms analysed using controlled drying pot experiments. Photosynthetic rates were significantly higher in the C4 than the C3 subspecies in the garden experiment under well-watered conditions, but this advantage was completely lost during a rainless period when unwatered plants experienced severe drought. Controlled drying experiments showed that this loss was caused by a greater increase in metabolic, rather than stomatal, limitations in C4 than in the C3 leaves. Decreases in CO2 assimilation resulted in lower electron transport rates and decreased photochemical efficiency under drought conditions, rather than increased electron transport to alternative sinks. These findings suggest that the high metabolic sensitivity of photosynthesis to severe drought seen previously in several C4 grass species may be an inherent characteristic of the C4 pathway. The mechanism may explain the paradox of why C4 species decline in arid environments despite high water-use efficiency.

  10. The roles of organic acids in C4 photosynthesis

    Directory of Open Access Journals (Sweden)

    Martha eLudwig

    2016-05-01

    Full Text Available Organic acids are involved in numerous metabolic pathways in all plants. The finding that some plants, known as C4 plants, have four-carbon dicarboxylic acids as the first product of carbon fixation showed these organic acids play essential roles as photosynthetic intermediates. Oxaloacetate, malate, and aspartate are substrates for the C4 acid cycle that underpins the CO2 concentrating mechanism of C4 photosynthesis. In this cycle, oxaloacetate is the immediate, short-lived, product of the initial CO2 fixation step in C4 leaf mesophyll cells. The malate and aspartate, resulting from the rapid conversion of oxaloacetate, are the organic acids delivered to the sites of carbon reduction in the bundle-sheath cells of the leaf, where they are decarboxylated, with the released CO2 used to make carbohydrates. The three-carbon organic acids resulting from the decarboxylation reactions are returned to the mesophyll cells where they are used to regenerate the CO2 acceptor pool. NADP-malic enzyme-type, NAD-malic enzyme-type and phosphoenolpyruvate carboxykinase-type C4 plants were identified, based on the most abundant decarboxylating enzyme in the leaf tissue. The genes encoding these C4 pathway-associated decarboxylases were co-opted from ancestral C3 plant genes during the evolution of C4 photosynthesis. Malate was recognized as the major organic acid transferred in NADP-malic enzyme-type C4 species, while aspartate fills this role in NAD-malic enzyme-type and phosphoenolpyruvate carboxykinase-type plants. However, accumulating evidence indicates that many C4 plants use a combination of organic acids and decarboxylases during CO2 fixation, and the C4-type categories are not rigid. The ability to transfer multiple organic acid species and utilize different decarboxylases has been suggested to give C4 plants advantages in changing and stressful environments, as well as during development, by facilitating the balance of energy between the two cell types

  11. The evolutionary ecology of C4 plants.

    Science.gov (United States)

    Christin, Pascal-Antoine; Osborne, Colin P

    2014-12-01

    C4 photosynthesis is a physiological syndrome resulting from multiple anatomical and biochemical components, which function together to increase the CO2 concentration around Rubisco and reduce photorespiration. It evolved independently multiple times and C4 plants now dominate many biomes, especially in the tropics and subtropics. The C4 syndrome comes in many flavours, with numerous phenotypic realizations of C4 physiology and diverse ecological strategies. In this work, we analyse the events that happened in a C3 context and enabled C4 physiology in the descendants, those that generated the C4 physiology, and those that happened in a C4 background and opened novel ecological niches. Throughout the manuscript, we evaluate the biochemical and physiological evidence in a phylogenetic context, which demonstrates the importance of contingency in evolutionary trajectories and shows how these constrained the realized phenotype. We then discuss the physiological innovations that allowed C4 plants to escape these constraints for two important dimensions of the ecological niche--growth rates and distribution along climatic gradients. This review shows that a comprehensive understanding of C4 plant ecology can be achieved by accounting for evolutionary processes spread over millions of years, including the ancestral condition, functional convergence via independent evolutionary trajectories, and physiological diversification. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

  12. Characterization of a C4 maize pyruvate orthophosphate dikinase ...

    African Journals Online (AJOL)

    PRECIOUS

    2010-01-11

    Jan 11, 2010 ... Indica “IR64”), a C3 plant. Expression of C4-PPDK in most transgenic rice lines resulted in increased CO2 ... affected the phenotypes of plants particularly tillers and enhanced yield of transgenic IR64 rice plants in the greenhouse. ... different tissue types and, depending on the species, this activity is found ...

  13. Senescence, dormancy and tillering in perennial C4 grasses

    Science.gov (United States)

    Perennial, temperate, C4 warm-season grasses, such as switchgrass and miscanthus have been tabbed as sources of herbaceous biomass for the production of green fuels and chemicals based on a number of positive agronomic traits. Although there is important literature on the management of these specie...

  14. Revealing diversity in structural and biochemical forms of C4 photosynthesis and a C3–C4 intermediate in genus Portulaca L. (Portulacaceae)

    Science.gov (United States)

    Voznesenskaya, Elena V.; Koteyeva, Nuria K.; Edwards, Gerald E.; Ocampo, Gilberto

    2010-01-01

    Portulacaceae is one of 19 families of terrestrial plants in which species having C4 photosynthesis have been found. Representative species from major clades of the genus Portulaca were studied to characterize the forms of photosynthesis structurally and biochemically. The species P. amilis, P. grandiflora, P. molokiniensis, P. oleracea, P. pilosa, and P. umbraticola belong to the subgenus Portulaca and are C4 plants based on leaf carbon isotope values, Kranz anatomy, and expression of key C4 enzymes. Portulaca umbraticola, clade Umbraticola, is NADP-malic enzyme (NADP-ME)-type C4 species, while P. oleracea and P. molokiniensis in clade Oleracea are NAD-ME-type C4 species, all having different forms of Atriplicoid-type leaf anatomy. In clade Pilosa, P. amilis, P. grandiflora, and P. pilosa are NADP-ME-type C4 species. They have Pilosoid-type anatomy in which Kranz tissues enclose peripheral vascular bundles with water storage in the centre of the leaf. Portulaca cf. bicolor, which belongs to subgenus Portulacella, is an NADP-ME C4 species with Portulacelloid-type anatomy; it has well-developed Kranz chlorenchyma surrounding lateral veins distributed in one plane under the adaxial epidermis with water storage cells underneath. Portulaca cryptopetala (clade Oleracea), an endemic species from central South America, was identified as a C3–C4 based on its intermediate CO2 compensation point and selective localization of glycine decarboxylase of the photorespiratory pathway in mitochondria of bundle sheath cells. The C4 Portulaca species which were examined also have cotyledons with Kranz-type anatomy, while the stems of all species have C3-type photosynthetic cells. The results indicate that multiple structural and biochemical forms of C4 photosynthesis evolved in genus Portulaca. PMID:20591900

  15. Evolution of CAM and C4 carbon-concentrating mechanisms

    Science.gov (United States)

    Keeley, Jon E.; Rundel, Philip W.

    2003-01-01

    Mechanisms for concentrating carbon around the Rubisco enzyme, which drives the carbon-reducing steps in photosynthesis, are widespread in plants; in vascular plants they are known as crassulacean acid metabolism (CAM) and C4 photosynthesis. CAM is common in desert succulents, tropical epiphytes, and aquatic plants and is characterized by nighttime fixation of CO2. The proximal selective factor driving the evolution of this CO2-concentrating pathway is low daytime CO2, which results from the unusual reverse stomatal behavior of terrestrial CAM species or from patterns of ambient CO2 availability for aquatic CAM species. In terrestrials the ultimate selective factor is water stress that has selected for increased water use efficiency. In aquatics the ultimate selective factor is diel fluctuations in CO2 availability for palustrine species and extreme oligotrophic conditions for lacustrine species. C4 photosynthesis is based on similar biochemistry but carboxylation steps are spatially separated in the leaf rather than temporally as in CAM. This biochemical pathway is most commonly associated with a specialized leaf anatomy known as Kranz anatomy; however, there are exceptions. The ultimate selective factor driving the evolution of this pathway is excessively high photorespiration that inhibits normal C3 photosynthesis under high light and high temperature in both terrestrial and aquatic habitats. CAM is an ancient pathway that likely has been present since the Paleozoic era in aquatic species from shallow-water palustrine habitats. While atmospheric CO2 levels have undoubtedly affected the evolution of terrestrial plant carbon-concentrating mechanisms, there is reason to believe that past atmospheric changes have not played as important a selective role in the aquatic milieu since palustrine habitats today are not generally carbon sinks, and the selective factors driving aquatic CAM are autogenic. Terrestrial CAM, in contrast, is of increasing selective value under

  16. ISLSCP II C4 Vegetation Percentage

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: The photosynthetic composition (C3 or C4) of vegetation on the land surface is essential for accurate simulations of biosphere-atmosphere exchanges of...

  17. ISLSCP II C4 Vegetation Percentage

    Data.gov (United States)

    National Aeronautics and Space Administration — The photosynthetic composition (C3 or C4) of vegetation on the land surface is essential for accurate simulations of biosphere-atmosphere exchanges of carbon, water,...

  18. C# 4.0 in a Nutshell

    CERN Document Server

    Albahari, Joseph

    2010-01-01

    What people are saying about C# 4.0 in a Nutshell "C# 4.0 in a Nutshell is one of the few books I keep on my desk as a quick reference. It is a book I recommend."--Scott Guthrie, Corporate Vice President, .NET Developer Platform, Microsoft Corporation "A must-read for a concise but thorough examination of the parallel programming features in the .NET Framework 4."--Stephen Toub, Parallel Computing Platform Program Manager, Microsoft "This wonderful book is a great reference for developers of all levels."-- Chris Burrows, C# Compiler Team, Microsoft When you have questions about how to u

  19. On the smell of Composition C-4.

    Science.gov (United States)

    Kranz, William; Kitts, Kelley; Strange, Nicholas; Cummins, Joshua; Lotspeich, Erica; Goodpaster, John

    2014-03-01

    In efforts to locate hidden explosives, humans have had few allies as valuable as the explosives-detecting canine. The unrivaled sensitivity and selectivity of the canine nose have combined to make these animals an attractive choice for law enforcement, military, and private security applications. Although the efficacy of trained detector dogs is well-established, the question of which chemical compounds are responsible for causing a dog to recognize a particular odor and alert to it remains a subject of debate for several explosive formulations--including, perhaps most notably, Composition C-4. Previous studies have indicated that cyclohexanone, 2,3-dimethyl-2,3-dinitrobutane, and 2-ethyl-1-hexanol are the chemicals that may cause canines to alert to C-4. This has led to the suggestion that these substances could be used as a substitute for genuine C-4 in the training, testing, and maintenance of explosives-detecting canines. In this paper, we present an alternative view. Using gas chromatography-mass spectrometry with solid phase microextraction as a pre-concentration technique, we have discovered that 2-ethyl-1-hexanol off-gasses not only from C-4, but also from benign sources, such as the common plasticizers bis(2-ethylhexyl)adipate, bis(2-ethylhexyl)sebacate, and bis(2-ethylhexyl)phthalate; as well as several plasticized items common to our everyday world, including PVC tile, PVC pipe, electrical tape, and credit cards. This observation may potentially discourage the use of 2-ethyl-1-hexanol for training purposes. We also present the results of our own canine field trials focused on the detection of C-4. Through the use of contingency tables and statistical testing, we demonstrate the failure of trained law enforcement dogs in our study to respond in any significant way to these potential odor compounds. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  20. Are changes in sulfate assimilation pathway needed for evolution of C4 photosynthesis?

    Science.gov (United States)

    Weckopp, Silke C; Kopriva, Stanislav

    2014-01-01

    C4 photosynthesis characteristically features a cell-specific localization of enzymes involved in CO2 assimilation in bundle sheath cells (BSC) or mesophyll cells. Interestingly, enzymes of sulfur assimilation are also specifically present in BSC of maize and many other C4 species. This localization, however, could not be confirmed in C4 species of the genus Flaveria. It was, therefore, concluded that the bundle sheath localization of sulfate assimilation occurs only in C4 monocots. However, recently the sulfate assimilation pathway was found coordinately enriched in BSC of Arabidopsis, opening new questions about the significance of such cell-specific localization of the pathway. In addition, next generation sequencing revealed expression gradients of many genes from C3 to C4 species and mathematical modeling proposed a sequence of adaptations during the evolutionary path from C3 to C4. Indeed, such gradient, with higher expression of genes for sulfate reduction in C4 species, has been observed within the genus Flaveria. These new tools provide the basis for reexamining the intriguing question of compartmentalization of sulfur assimilation. Therefore, this review summarizes the findings on spatial separation of sulfur assimilation in C4 plants and Arabidopsis, assesses the information on sulfur assimilation provided by the recent transcriptomics data and discusses their possible impact on understanding this interesting feature of plant sulfur metabolism to find out whether changes in sulfate assimilation are part of a general evolutionary trajectory toward C4 photosynthesis.

  1. Are changes in sulfate assimilation pathway needed for evolution of C4 photosynthesis?

    Directory of Open Access Journals (Sweden)

    Silke Christine Weckopp

    2015-01-01

    Full Text Available C4 photosynthesis characteristically features a cell-specific localization of enzymes involved in CO2 assimilation in bundle sheath cells or mesophyll cells. Interestingly, enzymes of sulfur assimilation are also specifically present in bundle sheath cells of maize and many other C4 species. This localization, however, could not be confirmed in C4 species of the genus Flaveria. It was, therefore, concluded that the bundle sheath localization of sulfate assimilation occurs only in C4 monocots. However, recently the sulfate assimilation pathway was found coordinately enriched in bundle sheath cells of Arabidopsis, opening new questions about the significance of such cell-specific localization of the pathway. In addition, next generation sequencing revealed expression gradients of many genes from C3 to C4 species and mathematical modelling proposed a sequence of adaptations during the evolutionary path from C3 to C4. Indeed, such gradient, with higher expression of genes for sulfate reduction in C4 species, has been observed within the genus Flaveria. These new tools provide the basis for reexamining the intriguing question of compartmentalization of sulfur assimilation. Therefore, this review summarizes the findings on spatial separation of sulfur assimilation in C4 plants and Arabidopsis, assesses the information on sulfur assimilation provided by the recent transcriptomics data and discusses their possible impact on understanding this interesting feature of plant sulfur metabolism to find out whether changes in sulfate assimilation are part of a general evolutionary trajectory towards C4 photosynthesis.

  2. Inactivation of C4orf26 in toothless placental mammals.

    Science.gov (United States)

    Springer, Mark S; Starrett, James; Morin, Phillip A; Lanzetti, Agnese; Hayashi, Cheryl; Gatesy, John

    2016-02-01

    Previous studies have reported inactivated copies of six enamel-related genes (AMBN, AMEL, AMTN, ENAM, KLK4, MMP20) and one dentin-related gene (DSPP) in one or more toothless vertebrates and/or vertebrates with enamelless teeth, thereby providing evidence that these genes are enamel or tooth-specific with respect to their critical functions that are maintained by natural selection. Here, we employ available genome sequences for edentulous and enamelless mammals to evaluate the enamel specificity of four genes (WDR72, SLC24A4, FAM83H, C4orf26) that have been implicated in amelogenesis imperfecta, a condition in which proper enamel formation is abrogated during tooth development. Coding sequences for WDR72, SCL24A4, and FAM83H are intact in four edentulous taxa (Chinese pangolin, three baleen whales) and three taxa (aardvark, nine-banded armadillo, Hoffmann's two-toed sloth) with enamelless teeth, suggesting that these genes have critical functions beyond their involvement in tooth development. By contrast, genomic data for C4orf26 reveal inactivating mutations in pangolin and bowhead whale as well as evidence for deletion of this gene in two minke whale species. Hybridization capture of exonic regions and PCR screens provide evidence for inactivation of C4orf26 in eight additional baleen whale species. However, C4orf26 is intact in all three species with enamelless teeth that were surveyed, as well as in 95 additional mammalian species with enamel-capped teeth. Estimates of selection intensity suggest that dN/dS ratios on branches leading to taxa with enamelless teeth are similar to the dN/dS ratio on branches leading to taxa with enamel-capped teeth. Based on these results, we conclude that C4orf26 is tooth-specific, but not enamel-specific, with respect to its essential functions that are maintained by natural selection. A caveat is that an alternative splice site variant, which translates exon 3 in a different reading frame, is putatively functional in

  3. Promotion of Cyclic Electron Transport Around Photosystem I with the Development of C4 Photosynthesis.

    Science.gov (United States)

    Munekage, Yuri Nakajima; Taniguchi, Yukimi Y

    2016-05-01

    C4 photosynthesis is present in approximately 7,500 species classified into 19 families, including monocots and eudicots. In the majority of documented cases, a two-celled CO2-concentrating system that uses a metabolic cycle of four-carbon compounds is employed. C4 photosynthesis repeatedly evolved from C3 photosynthesis, possibly driven by the survival advantages it bestows in the hot, often dry, and nutrient-poor soils of the tropics and subtropics. The development of the C4 metabolic cycle greatly increased the ATP demand in chloroplasts during the evolution of malic enzyme-type C4 photosynthesis, and the additional ATP required for C4 metabolism may be produced by the cyclic electron transport around PSI. Recent studies have revealed the nature of cyclic electron transport and the elevation of its components during C4 evolution. In this review, we discuss the energy requirements of C3 and C4 photosynthesis, the current model of cyclic electron transport around PSI and how cyclic electron transport is promoted during C4 evolution using studies on the genus Flaveria, which contains a number of closely related C3, C4 and C3-C4 intermediate species. © The Author 2016. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  4. Enzyme Regulation in C4 Photosynthesis 12

    Science.gov (United States)

    Jacquot, Jean-Pierre P.; Buchanan, Bob B.; Martin, F.; Vidal, J.

    1981-01-01

    NADP-malate dehydrogenase, a light-modulated enzyme of C4 photosynthesis, was purified to homogeneity from leaves of corn. The pure enzyme was activated by thioredoxin m that was reduced either photochemically (with ferredoxin and ferredoxin-thioredoxin reductase) or chemically (with dithiothreitol). Unactivated corn leaf NADP-malate dehydrogenase had a molecular weight of 50,000 to 60,000 and was chromophorefree. The enzyme appeared to have a high content of serine and glycine and to contain both S—S and SH groups. Consequently, NADP-malate dehydrogenase seems to be capable of undergoing reversible oxidation/reduction during its photoregulation. PMID:16661905

  5. C4 cycles: past, present, and future research on C4 photosynthesis.

    Science.gov (United States)

    Langdale, Jane A

    2011-11-01

    In the late 1960s, a vibrant new research field was ignited by the discovery that instead of fixing CO(2) into a C(3) compound, some plants initially fix CO(2) into a four-carbon (C(4)) compound. The term C(4) photosynthesis was born. In the 20 years that followed, physiologists, biochemists, and molecular and developmental biologists grappled to understand how the C(4) photosynthetic pathway was partitioned between two morphologically distinct cell types in the leaf. By the early 1990s, much was known about C(4) biochemistry, the types of leaf anatomy that facilitated the pathway, and the patterns of gene expression that underpinned the biochemistry. However, virtually nothing was known about how the pathway was regulated. It should have been an exciting time, but many of the original researchers were approaching retirement, C(4) plants were proving recalcitrant to genetic manipulation, and whole-genome sequences were not even a dream. In combination, these factors led to reduced funding and the failure to attract young people into the field; the endgame seemed to be underway. But over the last 5 years, there has been a resurgence of interest and funding, not least because of ambitious multinational projects that aim to increase crop yields by introducing C(4) traits into C(3) plants. Combined with new technologies, this renewed interest has resulted in the development of more sophisticated approaches toward understanding how the C(4) pathway evolved, how it is regulated, and how it might be manipulated. The extent of this resurgence is manifest by the publication in 2011 of more than 650 pages of reviews on different aspects of C(4). Here, I provide an overview of our current understanding, the questions that are being addressed, and the issues that lie ahead.

  6. Phylogeny of C4-photosynthesis enzymes based on algal transcriptomic and genomic data supports an archaeal/proteobacterial origin and multiple duplication for most C4-related genes.

    Directory of Open Access Journals (Sweden)

    Shan Chi

    Full Text Available Both Calvin-Benson-Bassham (C3 and Hatch-Slack (C4 cycles are most important autotrophic CO2 fixation pathways on today's Earth. C3 cycle is believed to be originated from cyanobacterial endosymbiosis. However, studies on evolution of different biochemical variants of C4 photosynthesis are limited to tracheophytes and origins of C4-cycle genes are not clear till now. Our comprehensive analyses on bioinformatics and phylogenetics of novel transcriptomic sequencing data of 21 rhodophytes and 19 Phaeophyceae marine species and public genomic data of more algae, tracheophytes, cyanobacteria, proteobacteria and archaea revealed the origin and evolution of C4 cycle-related genes. Almost all of C4-related genes were annotated in extensive algal lineages with proteobacterial or archaeal origins, except for phosphoenolpyruvate carboxykinase (PCK and aspartate aminotransferase (AST with both cyanobacterial and archaeal/proteobacterial origin. Notably, cyanobacteria may not possess complete C4 pathway because of the flawed annotation of pyruvate orthophosphate dikinase (PPDK genes in public data. Most C4 cycle-related genes endured duplication and gave rise to functional differentiation and adaptation in different algal lineages. C4-related genes of NAD-ME (NAD-malic enzyme and PCK subtypes exist in most algae and may be primitive ones, while NADP-ME (NADP-malic enzyme subtype genes might evolve from NAD-ME subtype by gene duplication in chlorophytes and tracheophytes.

  7. The Road to C4 Photosynthesis: Evolution of a Complex Trait via Intermediary States.

    Science.gov (United States)

    Schlüter, Urte; Weber, Andreas P M

    2016-05-01

    C4 photosynthesis enables high photosynthetic energy conversion efficiency as well as high nitrogen and water use efficiencies. Given the multitude of biochemical, structural and molecular changes in comparison with C3 photosynthesis, it appears unlikely that such a complex trait would evolve in a single step. C4 photosynthesis is therefore believed to have evolved from the ancestral C3 state via intermediary stages. Consequently, the identification and detailed characterization of plant species representing transitory states between C3 and C4 is important for the reconstruction of the sequence of evolutionary events, especially since C4 evolution occurred in very different phylogenetic backgrounds. There is also significant interest in engineering of C4 or at least C4-like elements into C3 crop plants. A detailed and mechanistic understanding of C3-C4 intermediates is likely to provide guidance for the experimental design of such approaches. Here we provide an overview on the most relevant results obtained on C3-C4 intermediates to date. Recent knowledge gains in this field will be described in more detail. We thereby concentrate especially on biochemical and physiological work. Finally, we will provide a perspective and outlook on the continued importance of research on C3-C4 intermediates. © The Author 2016. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  8. The potential of C4 grasses for cellulosic biofuel production

    Directory of Open Access Journals (Sweden)

    Tim eWeijde

    2013-05-01

    Full Text Available With the advent of biorefinery technologies enabling plant biomass to be processed into biofuel, many researchers set out to study and improve candidate biomass crops. Many of these candidates are C4 grasses, characterized by a high productivity and resource use efficiency. In this review the potential of five C4 grasses as lignocellulose feedstock for biofuel production is discussed. These include three important field crops - maize, sugarcane and sorghum - and two undomesticated perennial energy grasses - miscanthus and switchgrass. Although all these grasses are high yielding, they produce different products. While miscanthus and switchgrass are exploited exclusively for lignocellulosic biomass, maize, sorghum and sugarcane are dual-purpose crops. It is unlikely that all the prerequisites for the sustainable and economic production of biomass for a global cellulosic biofuel industry will be fulfilled by a single crop. High and stable yields of lignocellulose are required in diverse environments worldwide, to sustain a year-round production of biofuel. A high resource use efficiency is indispensable to allow cultivation with minimal inputs of nutrients and water and the exploitation of marginal soils for biomass production. Finally, the lignocellulose composition of the feedstock should be optimized to allow its efficient conversion into biofuel and other by-products. Breeding for these objectives should encompass diverse crops, to meet the demands of local biorefineries and provide adaptability to different environments. Collectively, these C4 grasses are likely to play a central role in the supply of lignocellulose for the cellulosic ethanol industry. Moreover, as these species are evolutionary closely related, advances in each of these crops will expedite improvements in the other crops. This review aims to provide an overview of their potential, prospects and research needs as lignocellulose feedstocks for the commercial production of

  9. The potential of C4 grasses for cellulosic biofuel production

    Science.gov (United States)

    van der Weijde, Tim; Alvim Kamei, Claire L.; Torres, Andres F.; Vermerris, Wilfred; Dolstra, Oene; Visser, Richard G. F.; Trindade, Luisa M.

    2013-01-01

    With the advent of biorefinery technologies enabling plant biomass to be processed into biofuel, many researchers set out to study and improve candidate biomass crops. Many of these candidates are C4 grasses, characterized by a high productivity and resource use efficiency. In this review the potential of five C4 grasses as lignocellulosic feedstock for biofuel production is discussed. These include three important field crops—maize, sugarcane and sorghum—and two undomesticated perennial energy grasses—miscanthus and switchgrass. Although all these grasses are high yielding, they produce different products. While miscanthus and switchgrass are exploited exclusively for lignocellulosic biomass, maize, sorghum, and sugarcane are dual-purpose crops. It is unlikely that all the prerequisites for the sustainable and economic production of biomass for a global cellulosic biofuel industry will be fulfilled by a single crop. High and stable yields of lignocellulose are required in diverse environments worldwide, to sustain a year-round production of biofuel. A high resource use efficiency is indispensable to allow cultivation with minimal inputs of nutrients and water and the exploitation of marginal soils for biomass production. Finally, the lignocellulose composition of the feedstock should be optimized to allow its efficient conversion into biofuel and other by-products. Breeding for these objectives should encompass diverse crops, to meet the demands of local biorefineries and provide adaptability to different environments. Collectively, these C4 grasses are likely to play a central role in the supply of lignocellulose for the cellulosic ethanol industry. Moreover, as these species are evolutionary closely related, advances in each of these crops will expedite improvements in the other crops. This review aims to provide an overview of their potential, prospects and research needs as lignocellulose feedstocks for the commercial production of biofuel. PMID:23653628

  10. Olefins production from C4 stream; Producao de olefinas a partir de corrente C4

    Energy Technology Data Exchange (ETDEWEB)

    Basso, Julia A.; Feltran, Marina B.; Becker, Patricia Luiza; Rocha, Priscila L. [PETROBRAS, Rio de Janeiro, RJ (Brazil)

    2008-07-01

    The petrochemical sector in Brazil has been growing in terms of investment and expansion of production capacity, due to increased demand for thermoplastic products. However, the offer of basic petrochemical raw materials obtained by conventional routes is not following this increasing demand which stimulates the search for new competitive technologies. Moreover, there is the opportunity to use low value added C4 streams from FCC process that are available in the Brazilian refineries, for the production of petrochemicals. Several possibilities of C4 stream use to produce butadienes, MTBE, maleic anhydride, ethylene and propylene have been discussed in this work. The production of propylene seems to be the most economically attractive option in Brazil, since its offer will not keep up with the growth in its demand, according to ABIQUIM forecasts. Therefore some propylene production technologies from C4 streams - steam cracking, metathesis and selective cracking - have been evaluated considering their basic characteristics and applications. The goal of this study is to provide preliminary information to support future project evaluations of petrochemical/refinery integration, through comparative analysis of these technologies. (author)

  11. Solvation Thermodynamic Properties of Hydrogen Sulfide in [C4mim][PF6], [C4mim][BF4], and [C4mim][Cl] Ionic Liquids, Determined by Molecular Simulations.

    Science.gov (United States)

    Sánchez-Badillo, Joel; Gallo, Marco; Alvarado, Sandra; Glossman-Mitnik, Daniel

    2015-08-20

    Removal of hydrogen sulfide (H2S) and acid gases from natural gas is accomplished by absorption processes using a solvent. The gas solubility in a liquid can be used to measure the degree of removal of the gas and is quantified by the Henry's constant, the free energy of solvation at infinite dilution, or the excess chemical potential. In this work, Henry's constants and thermodynamic properties of solvation of H2S were calculated in three ionic liquids: [C4mim][PF6], [C4mim][BF4], and [C4mim][Cl] ([C4mim], 1-butyl-3-methyl imidazolium). The first step in this work was the evaluation of the force fields for the gas and condensed phases in order to obtain accurate values for the excess chemical potential for H2S on each ionic liquid using free energy perturbation techniques. In the H2S-[C4mim][PF6] and H2S-[C4mim][BF4] systems, the results obtained by molecular simulation agree with the experimental values reported in the literature. However, the solvation free energy calculated for the H2S-[C4mim][Cl] system can be considered predictive because of the lack of experimental data at the simulated conditions. Based on these results, the best solvent for removing H2S is [C4mim][Cl] because it has the highest affinity for this species (lowest value of the Henry's constant). Also, solvation thermodynamic properties such as enthalpy and entropy were calculated in order to evaluate their contribution to the free energy of solvation.

  12. A Common histone modification code on C4 genes in maize and its conservation in Sorghum and Setaria italica.

    Science.gov (United States)

    Heimann, Louisa; Horst, Ina; Perduns, Renke; Dreesen, Björn; Offermann, Sascha; Peterhansel, Christoph

    2013-05-01

    C4 photosynthesis evolved more than 60 times independently in different plant lineages. Each time, multiple genes were recruited into C4 metabolism. The corresponding promoters acquired new regulatory features such as high expression, light induction, or cell type-specific expression in mesophyll or bundle sheath cells. We have previously shown that histone modifications contribute to the regulation of the model C4 phosphoenolpyruvate carboxylase (C4-Pepc) promoter in maize (Zea mays). We here tested the light- and cell type-specific responses of three selected histone acetylations and two histone methylations on five additional C4 genes (C4-Ca, C4-Ppdk, C4-Me, C4-Pepck, and C4-RbcS2) in maize. Histone acetylation and nucleosome occupancy assays indicated extended promoter regions with regulatory upstream regions more than 1,000 bp from the transcription initiation site for most of these genes. Despite any detectable homology of the promoters on the primary sequence level, histone modification patterns were highly coregulated. Specifically, H3K9ac was regulated by illumination, whereas H3K4me3 was regulated in a cell type-specific manner. We further compared histone modifications on the C4-Pepc and C4-Me genes from maize and the homologous genes from sorghum (Sorghum bicolor) and Setaria italica. Whereas sorghum and maize share a common C4 origin, C4 metabolism evolved independently in S. italica. The distribution of histone modifications over the promoters differed between the species, but differential regulation of light-induced histone acetylation and cell type-specific histone methylation were evident in all three species. We propose that a preexisting histone code was recruited into C4 promoter control during the evolution of C4 metabolism.

  13. Product Manager C4ISR On-The-Move Experimentation

    National Research Council Canada - National Science Library

    Utroska, William; Langan, Russell; Amabile, Michael

    2006-01-01

    Product Manager C4ISR On-The-Move (PM C4ISR OTM) provides a relevant operational field experimentation venue for the purpose of assessing emerging technologies in a System-of- Systems (SoS) environment...

  14. Complement C4 phenotypes in dementia of the Alzheimer type

    NARCIS (Netherlands)

    Eikelenboom, P.; Goetz, J.; Pronk, J. C.; Hauptmann, G.

    1988-01-01

    Complement C4 phenotype distribution was studied in 64 patients with dementia of the Alzheimer type. In contrast to reported findings we failed to find a significant association between C4B2 gene frequency and Alzheimer's dementia

  15. Chronic effects of the ionic liquid [C4mim][Cl] towards the microalga Scenedesmus quadricauda.

    Science.gov (United States)

    Deng, Yun; Beadham, Ian; Wu, Jie; Chen, Xiao-Di; Hu, Lan; Gu, Jun

    2015-09-01

    Chronic effects of the ionic liquid [C4mim][Cl] (mp 73 °C) towards the microalga, Scenedesmus quadricauda were studied by flow cytometry, monitoring multiple endpoints of cell density, esterase activity, membrane integrity, reactive oxygen species and chlorophyll fluorescence. Toxicity was clearly in evidence, and although increased esterase activity indicated hormesis during initial exposure to [C4mim][Cl], inhibition of both esterase activity and chlorophyll fluorescence became apparent after 3 days. Cell density was also decreased by culturing with [C4mim][Cl], but this effect was clearly concentration-dependent and only became significant during the second half of the experiment. In contrast, [C4mim][Cl] had only a modest effect on reactive oxygen species (ROS) and caused little damage to cell membranes. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. The role of photorespiration during the evolution of C4 photosynthesis in the genus Flaveria

    Science.gov (United States)

    Mallmann, Julia; Heckmann, David; Bräutigam, Andrea; Lercher, Martin J; Weber, Andreas PM; Westhoff, Peter; Gowik, Udo

    2014-01-01

    C4 photosynthesis represents a most remarkable case of convergent evolution of a complex trait, which includes the reprogramming of the expression patterns of thousands of genes. Anatomical, physiological, and phylogenetic and analyses as well as computational modeling indicate that the establishment of a photorespiratory carbon pump (termed C2 photosynthesis) is a prerequisite for the evolution of C4. However, a mechanistic model explaining the tight connection between the evolution of C4 and C2 photosynthesis is currently lacking. Here we address this question through comparative transcriptomic and biochemical analyses of closely related C3, C3–C4, and C4 species, combined with Flux Balance Analysis constrained through a mechanistic model of carbon fixation. We show that C2 photosynthesis creates a misbalance in nitrogen metabolism between bundle sheath and mesophyll cells. Rebalancing nitrogen metabolism requires anaplerotic reactions that resemble at least parts of a basic C4 cycle. Our findings thus show how C2 photosynthesis represents a pre-adaptation for the C4 system, where the evolution of the C2 system establishes important C4 components as a side effect. DOI: http://dx.doi.org/10.7554/eLife.02478.001 PMID:24935935

  17. Understanding metabolite transport and metabolism in C4 plants through RNA-seq.

    Science.gov (United States)

    Schlüter, Urte; Denton, Alisandra K; Bräutigam, Andrea

    2016-06-01

    RNA-seq, the measurement of steady-state RNA levels by next generation sequencing, has enabled quantitative transcriptome analyses of complex traits in many species without requiring the parallel sequencing of their genomes. The complex trait of C4 photosynthesis, which increases photosynthetic efficiency via a biochemical pump that concentrates CO2 around RubisCO, has evolved convergently multiple times. Due to these interesting properties, C4 photosynthesis has been analyzed in a series of comparative RNA-seq projects. These projects compared both species with and without the C4 trait and different tissues or organs within a C4 plant. The RNA-seq studies were evaluated by comparing to earlier single gene studies. The studies confirmed the marked changes expected for C4 signature genes, but also revealed numerous new players in C4 metabolism showing that the C4 cycle is more complex than previously thought, and suggesting modes of integration into the underlying C3 metabolism. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Applicability of Virtual Environments as C4ISR Displays

    Science.gov (United States)

    2006-06-01

    und Führungssysteme FORSCHUNGSINSTITUT FÜR KOMMUNIKATION , INFORMATIONSVERARBEITUNG UND ERGONOMIEFGAN Applicability of Virtual Environments as C4ISR...Führungssysteme FORSCHUNGSINSTITUT FÜR KOMMUNIKATION , INFORMATIONSVERARBEITUNG UND ERGONOMIE 1 FGAN Applicability of Virtual Environments as C4ISR Displays...Führungssysteme FORSCHUNGSINSTITUT FÜR KOMMUNIKATION , INFORMATIONSVERARBEITUNG UND ERGONOMIE 2 FGAN C4ISR C4ISR stands for - Command (ability of mil. com

  19. Differential freezing resistance and photoprotection in C3 and C4 eudicots and grasses.

    Science.gov (United States)

    Liu, Mei-Zhen; Osborne, Colin P

    2013-05-01

    Globally, C4 plants dominate hot, open environments, but this general pattern is underpinned by important differences in the biogeography of C4 lineages. In particular, the species richness of C4 Poaceae (grasses) increases strongly with increasing temperature, whereas that of the major C4 eudicot group Chenopodiaceae correlates positively with aridity. Freezing tolerance is a crucial determinant of biogeographical relationships with temperature and is mediated by photodamage and cellular disruption by desiccation, but little is known about differences between C4 families. This study hypothesized that there is a greater risk of freezing damage via these mechanisms in C4 Poaceae than Chenopodiaceae, that freezing protection differs between the taxonomic groups, and that freezing tolerance of species is linked to arid habitat preference. Chlorophyll fluorescence, water relations, and freezing injury were compared in four C3 and six C4 species of Poaceae and Chenopodiaceae from the same Mongolian flora. Contrary to expectations, freezing-induced leaf mortality and photodamage were lower in Poaceae than Chenopodiaceae species, and unrelated to photosynthetic pathway. The freezing resistance of Poaceae species resulted from constitutive protection and cold acclimation and an ability to protect the photosynthetic apparatus from photodamage. Freezing protection was associated with low osmotic potential and low tissue elasticity, and freezing damage was accompanied by electrolyte leakage, consistent with cell-membrane disruption by ice. Both Chenopodiaceae and Poaceae had the potential to develop cold acclimation and withstand freezing during the growing season, which conflicted with the hypothesis. Instead, freezing tolerance was more closely associated with life history and ecological preference in these Mongolian species.

  20. Differential freezing resistance and photoprotection in C3 and C4 eudicots and grasses

    Science.gov (United States)

    Liu, Mei-Zhen; Osborne, Colin P.

    2013-01-01

    Globally, C4 plants dominate hot, open environments, but this general pattern is underpinned by important differences in the biogeography of C4 lineages. In particular, the species richness of C4 Poaceae (grasses) increases strongly with increasing temperature, whereas that of the major C4 eudicot group Chenopodiaceae correlates positively with aridity. Freezing tolerance is a crucial determinant of biogeographical relationships with temperature and is mediated by photodamage and cellular disruption by desiccation, but little is known about differences between C4 families. This study hypothesized that there is a greater risk of freezing damage via these mechanisms in C4 Poaceae than Chenopodiaceae, that freezing protection differs between the taxonomic groups, and that freezing tolerance of species is linked to arid habitat preference. Chlorophyll fluorescence, water relations, and freezing injury were compared in four C3 and six C4 species of Poaceae and Chenopodiaceae from the same Mongolian flora. Contrary to expectations, freezing-induced leaf mortality and photodamage were lower in Poaceae than Chenopodiaceae species, and unrelated to photosynthetic pathway. The freezing resistance of Poaceae species resulted from constitutive protection and cold acclimation and an ability to protect the photosynthetic apparatus from photodamage. Freezing protection was associated with low osmotic potential and low tissue elasticity, and freezing damage was accompanied by electrolyte leakage, consistent with cell-membrane disruption by ice. Both Chenopodiaceae and Poaceae had the potential to develop cold acclimation and withstand freezing during the growing season, which conflicted with the hypothesis. Instead, freezing tolerance was more closely associated with life history and ecological preference in these Mongolian species. PMID:23599273

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

    African Journals Online (AJOL)

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

  2. 17 CFR 240.16c-4 - Derivative securities.

    Science.gov (United States)

    2010-04-01

    ... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Derivative securities. 240.16c-4 Section 240.16c-4 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION (CONTINUED... Exchange Act of 1934 Exemption of Certain Transactions from Section 16(c) § 240.16c-4 Derivative securities...

  3. Polypeptide Composition of Envelope Membranes Isolated from Chloroplasts of C_3, C_4, and CAM Plants

    OpenAIRE

    Joyce G., Foster; Gerald E, Edwards; Department of Botany, Washington State University:(Present)United States Department of Agriculture, Appalachian Soil and Water Conservation Research Laboratory; Department of Botany, Washington State University

    1983-01-01

    Chloroplast envelopes were isolated from chloroplasts purified from Spinacea oleracea L. (C_3), Panicum miliaceum L. (NAD-malic enzyme-type C_4), Digitaria sanguinalis (L.) Scop. (NADP-malic enzyme-type C_4). Kalanchoe daigremontiana Hamet et Perrier (constitutive CAM), and from Mesembryanthemum crystallinum L. (inducible CAM) performing either C_3 photosynthesis or Crassulacean acid metabolism (CAM). For each species, methods were developed to isolate chloroplast envelopes free of thylakoid ...

  4. Promotion of cyclic electron transport around photosystem I during the evolution of NADP-malic enzyme-type C4 photosynthesis in the genus Flaveria.

    Science.gov (United States)

    Nakamura, Naoya; Iwano, Megumi; Havaux, Michel; Yokota, Akiho; Munekage, Yuri Nakajima

    2013-08-01

    C4 plants display higher cyclic electron transport activity than C3 plants. This activity is suggested to be important for the production of ATPs required for C4 metabolism. To understand the process by which photosystem I (PSI) cyclic electron transport was promoted during C4 evolution, we conducted comparative analyses of the functionality of PSI cyclic electron transport among members of the genus Flaveria, which contains several C3, C3-C4 intermediate, C4-like and C4 species. The abundance of NDH-H, a subunit of NADH dehydrogenase-like complex, increased markedly in bundle sheath cells with the activity of the C4 cycle. By contrast, PROTON GRADIENT REGULATION5 (PGR5) and PGR5-LIKE1 increased in both mesophyll and bundle sheath cells in C4-like Flaveria palmeri and C4 species. Grana stacks were drastically reduced in bundle sheath chloroplasts of C4-like F. palmeri and C4 species; these species showed a marked increase in PSI cyclic electron transport activity. These results suggest that both the expression of proteins involved in PSI cyclic electron transport and changes in thylakoid structure contribute to the high activity of cyclic electron flow in NADP-malic enzyme-type C4 photosynthesis. We propose that these changes were important for the establishment of C4 photosynthesis from C3-C4 intermediate photosynthesis in Flaveria. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  5. Complement factor C4 activation in patients with hereditary angioedema

    DEFF Research Database (Denmark)

    Åbom, Anne; Bygum, Anette; Koch, Claus

    2017-01-01

    Objectives: Low complement factor C4 is usually considered a valuable screening tool for patients with the potentially life-threatening hereditary angioedema with C1-inhibitor (C1-INH) deficiency (C1-INH-HAE). However, there are patients with C1-INH-HAE presenting with normal C4 levels. This means......, that C1-INH-HAE may potentially be overlooked, if screening is performed only by measurement of C4. It has been suggested that measurement of C4 activation products is better suited to avoid false negative results. Our aim was to investigate whether total antigenic C4 or non-functional C4c is a better...... measure of the increased C4 activation in C1-INH-HAE patients. Design and methods: Two different monoclonal antibodies (mAb) to human C4 were produced: one had specificity for the β-chain of C4 and would thus react with both functional and non-functional C4, and the other was developed against the factor...

  6. Short-term thermal photosynthetic responses of C4 grasses are independent of the biochemical subtype.

    Science.gov (United States)

    Sonawane, Balasaheb V; Sharwood, Robert E; von Caemmerer, Susanne; Whitney, Spencer M; Ghannoum, Oula

    2017-11-28

    C4 photosynthesis evolved independently many times, resulting in multiple biochemical pathways; however, little is known about how these different pathways respond to temperature. We investigated the photosynthetic responses of eight C4 grasses belonging to three biochemical subtypes (NADP-ME, PEP-CK, and NAD-ME) to four leaf temperatures (18, 25, 32, and 40 °C). We also explored whether the biochemical subtype influences the thermal responses of (i) in vitro PEPC (Vpmax) and Rubisco (Vcmax) maximal activities, (ii) initial slope (IS) and CO2-saturated rate (CSR) derived from the A-Ci curves, and (iii) CO2 leakage out of the bundle sheath estimated from carbon isotope discrimination. We focussed on leakiness and the two carboxylases because they determine the coordination of the CO2-concentrating mechanism and are important for parameterizing the semi-mechanistic C4 photosynthesis model. We found that the thermal responses of Vpmax and Vcmax, IS, CSR, and leakiness varied among the C4 species independently of the biochemical subtype. No correlation was observed between Vpmax and IS or between Vcmax and CSR; while the ratios Vpmax/Vcmax and IS/CSR did not correlate with leakiness among the C4 grasses. Determining mesophyll and bundle sheath conductances in diverse C4 grasses is required to further elucidate how C4 photosynthesis responds to temperature. © Society for Experimental Biology 2017.

  7. Evolutionary analysis of two complement C4 genes: Ancient duplication and conservation during jawed vertebrate evolution.

    Science.gov (United States)

    Nonaka, Mayumi I; Terado, Tokio; Kimura, Hiroshi; Nonaka, Masaru

    2017-03-01

    The complement C4 is a thioester-containing protein, and a histidine (H) residue catalyzes the cleavage of the thioester to allow covalent binding to carbohydrates on target cells. Some mammalian and teleost species possess an additional isotype where the catalytic H is replaced by an aspartic acid (D), which binds preferentially to proteins. We found the two C4 isotypes in many other jawed vertebrates, including sharks and birds/reptiles. Phylogenetic analysis suggested that C4 gene duplication occurred in the early days of the jawed vertebrate evolution. The D-type C4 of bony fish except for mammals formed a cluster, termed D-lineage. The D-lineage genes were located in a syntenic region outside MHC, and evolved conservatively. Mammals lost the D-lineage before speciation, but D-type C4 was regenerated by recent gene duplication in some mammalian species or groups. Dual C4 molecules with different substrate specificities would have contributed to development of the antibody-dependent classical pathway. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Diversification of C(4) grasses (Poaceae) does not coincide with their ecological dominance.

    Science.gov (United States)

    Bouchenak-Khelladi, Yanis; Slingsby, Jasper A; Verboom, G Anthony; Bond, William J

    2014-02-01

    The radiation of a lineage and its rise to ecological dominance are distinct phenomena and driven by different processes. For example, paleoecological data has been used to show that the Cretaceous angiosperm radiation did not coincide with their rise to dominance. Using a phylogenetic approach, we here explored the evolution of C4 grasses and evaluated whether the diversification of this group and its rise to ecological dominance in the late Miocene were decoupled. We assembled a matrix including 675 grass species of the PACMAD clade and 2784 characters (ITS and ndhF) to run a molecular dating analysis using three fossils as reference calibrations. We coded species as C3 vs. C4 and reconstructed ancestral states under maximum likelihood. We used the program BiSSE to test whether rates of diversification are correlated with photosynthetic pathway and whether the radiation of C4 lineages preceded or coincided with their rise to ecological dominance from ∼10 Ma. C4 grass lineages first originated around 35 Ma at the time of the Eocene-Oligocene transition. Accelerated diversification of C4 lineages did not coincide with their rise to ecological dominance. C4-dominated grasslands have expanded only since the Late Miocene and Pliocene. The initial diversification of their biotic elements can be tracked back as far as the Eocene-Oligocene transition. We suggest that shifts in taxonomic diversification and ecological dominance were stimulated by different factors, as in the case of the early angiosperms in the Cretaceous.

  9. Diversity in forms of C4 in the genus Cleome (Cleomaceae)

    Science.gov (United States)

    Koteyeva, Nuria K.; Voznesenskaya, Elena V.; Roalson, Eric H.; Edwards, Gerald E.

    2011-01-01

    Background and Aims Cleomaceae is one of 19 angiosperm families in which C4 photosynthesis has been reported. The aim of the study was to determine the type, and diversity, of structural and functional forms of C4 in genus Cleome. Methods Plants of Cleome species were grown from seeds, and leaves were subjected to carbon isotope analysis, light and scanning electron microscopy, western blot analysis of proteins, and in situ immunolocalization for ribulose bisphosphate carboxylase oxygenase (Rubisco) and phosphoenolpyruvate carboxylase (PEPC). Key Results Three species with C4-type carbon isotope values occurring in separate lineages in the genus (Cleome angustifolia, C. gynandra and C. oxalidea) were shown to have features of C4 photosynthesis in leaves and cotyledons. Immunolocalization studies show that PEPC is localized in mesophyll (M) cells and Rubisco is selectively localized in bundle sheath (BS) cells in leaves and cotyledons, characteristic of species with Kranz anatomy. Analyses of leaves for key photosynthetic enzymes show they have high expression of markers for the C4 cycle (compared with the C3–C4 intermediate C. paradoxa and the C3 species C. africana). All three are biochemically NAD-malic enzyme sub-type, with higher granal development in BS than in M chloroplasts, characteristic of this biochemical sub-type. Cleome gynandra and C. oxalidea have atriplicoid-type Kranz anatomy with multiple simple Kranz units around individual veins. However, C. angustifolia anatomy is represented by a double layer of concentric chlorenchyma forming a single compound Kranz unit by surrounding all the vascular bundles and water storage cells. Conclusions NAD-malic enzyme-type C4 photosynthesis evolved multiple times in the family Cleomaceae, twice with atriplicoid-type anatomy in compound leaves having flat, broad leaflets in the pantropical species C. gynandra and the Australian species C. oxalidea, and once by forming a single Kranz unit in compound leaves with

  10. Development and Analysis of Integrated C4ISR Architectures

    National Research Council Canada - National Science Library

    Giammarco, Kristin; Carlomusto, Michael; Lock, J. D

    2005-01-01

    .... This paper presents an overview of the Communications- Electronics Research, Development, and Engineering Center Command, Control, Communications, Computer, Intelligence, Surveillance, and Reconnaissance (C4ISR...

  11. Deconstructing Kranz anatomy to understand C4 evolution.

    Science.gov (United States)

    Lundgren, Marjorie R; Osborne, Colin P; Christin, Pascal-Antoine

    2014-07-01

    C4 photosynthesis is a complex physiological adaptation that confers greater productivity than the ancestral C3 photosynthetic type in environments where photorespiration is high. It evolved in multiple lineages through the coordination of anatomical and biochemical components, which concentrate CO2 at the active site of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). In most C4 plants, the CO2-concentrating mechanism is achieved via the confinement of Rubisco to bundle-sheath cells, into which CO2 is biochemically pumped from surrounding mesophyll cells. The C4 biochemical pathway relies on a specific suite of leaf functional properties, often referred to as Kranz anatomy. These include the existence of discrete compartments differentially connected to the atmosphere, a close contact between these compartments, and a relatively large compartment to host the Calvin cycle. In this review, we use a quantitative dataset for grasses (Poaceae) and examples from other groups to isolate the changes in anatomical characteristics that generate these functional properties, including changes in the size, number, and distribution of different cell types. These underlying anatomical characteristics vary among C4 origins, as similar functions emerged via different modifications of anatomical characteristics. In addition, the quantitative characteristics of leaves all vary continuously across C3 and C4 taxa, resulting in C4-like values in some C3 taxa. These observations suggest that the evolution of C4-suitable anatomy might require relatively few changes in plant lineages with anatomical predispositions. Furthermore, the distribution of anatomical traits across C3 and C4 taxa has important implications for the functional diversity observed among C4 lineages and for the approaches used to identify genetic determinants of C4 anatomy. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For

  12. Improving our understanding of environmental controls on the distribution of C3 and C4 grasses.

    Science.gov (United States)

    Pau, Stephanie; Edwards, Erika J; Still, Christopher J

    2013-01-01

    A number of studies have demonstrated the ecological sorting of C3 and C4 grasses along temperature and moisture gradients. However, previous studies of C3 and C4 grass biogeography have often inadvertently compared species in different and relatively unrelated lineages, which are associated with different environmental settings and distinct adaptive traits. Such confounded comparisons of C3 and C4 grasses may bias our understanding of ecological sorting imposed strictly by photosynthetic pathway. Here, we used MaxEnt species distribution modeling in combination with satellite data to understand the functional diversity of C3 and C4 grasses by comparing both large clades and closely related sister taxa. Similar to previous work, we found that C4 grasses showed a preference for regions with higher temperatures and lower precipitation compared with grasses using the C3 pathway. However, air temperature differences were smaller (2 °C vs. 4 °C) and precipitation and % tree cover differences were larger (1783 mm vs. 755 mm, 21.3% vs. 7.7%, respectively) when comparing C3 and C4 grasses within the same clade vs. comparing all C4 and all C3 grasses (i.e., ignoring phylogenetic structure). These results were due to important differences in the environmental preferences of C3 BEP and PACMAD clades (the two main grass clades). Winter precipitation was found to be more important for understanding the distribution and environmental niche of C3 PACMADs in comparison with both C3 BEPs and C4 taxa, for which temperature was much more important. Results comparing closely related C3 -C4 sister taxa supported the patterns derived from our modeling of the larger clade groupings. Our findings, which are novel in comparing the distribution and niches of clades, demonstrate that the evolutionary history of taxa is important for understanding the functional diversity of C3 and C4 grasses, and should have implications for how grasslands will respond to global change. © 2012

  13. The recurrent assembly of C4 photosynthesis, an evolutionary tale.

    Science.gov (United States)

    Christin, Pascal-Antoine; Osborne, Colin P

    2013-11-01

    Today, plants using C4 photosynthesis are widespread and important components of major tropical and subtropical biomes, but the events that led to their evolution and success started billions of years ago (bya). A CO2-fixing enzyme evolved in the early Earth atmosphere with a tendency to confuse CO2 and O2 molecules. The descendants of early photosynthetic organisms coped with this property in the geological eras that followed through successive fixes, the latest of which is the addition of complex CO2-concentrating mechanisms such as C4 photosynthesis. This trait was assembled from bricks available in C3 ancestors, which were altered to fulfill their new role in C4 photosynthesis. The existence of C4-suitable bricks probably determined the lineages of plants that could make the transition to C4 photosynthesis, highlighting the power of contingency in evolution. Based on the latest findings in C4 research, we present the evolutionary tale of C4 photosynthesis, with a focus on the general evolutionary phenomena that it so wonderfully exemplifies.

  14. The rise of C4 grassland ecosystems, a climate puzzle

    Science.gov (United States)

    Henderson, A.; Fox, D.; Freeman, K. H.

    2011-12-01

    The expansion of grasslands was one of the most profound ecological changes in the Cenozoic. Understanding the history of forest to grassland transitions, and the development of C4 grasslands in particular, is critical for understanding the relationship between land surface climate feedbacks, seasonality, and temperature. Modern distributions and ecological experiments demonstrate a strong correlation between C4 biogeography and high growing season temperatures and precipitation, as well as low pCO2 concentrations. The rise of C4 grasses in North America, as documented by carbonate nodule and mammal teeth δ13C values, began during a warm period with relatively stable pCO2 in the late Miocene. Surprisingly, C4 grasses continued to expand and then rose to dominance in the Great Plains as climates progressively cooled, moisture availability increased, and ice sheets formed further north on the continent. To understand this seemingly paradoxical scenario, we need constraints on the rate and character of increasing abundances of C4 vegetation. To this end, we use molecular and isotopic tools from terrestrial plant leaf wax n-alkanes extracted from carbonate nodules in the Meade Basin, Kansas and sites in Texas for the past 12 Ma. These records offer site-specific reconstructions tied directly to vegetation source. We compare our results to published continental-scale reconstructions of n-alkanes from the Mississippi River drainage basin and to climate records. From the distribution of C27 to C33 n-alkane abundances and patterns in δ13C values, we infer that C4 grasses coexisted with patches of C3 vegetation, including both grasses and trees. C4 grasses increasingly dominated the landscape, reaching modern abundances as ice sheets were reaching their southern limit in North America. Our results confirm that C4 grasslands emerged under cool and wet conditions, something we would not predict based on modern analogues, raising questions about our understanding of the

  15. Isomerisation of c4-c6 aldoses with zeolites

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention relates to isomerization of C4-C6 aldoses to their corresponding C4-C6 ketoses. In particular, the invention concerns isomerization of C4-C6 aldoses over solid zeolite catalysts free of any metals other than aluminum, in the presence of suitable solvent(s) at suitable elevat...... in the catalyst. The ketoses obtained are used as sweeteners in the food and/or brewery industry, or treated to obtain downstream platform chemicals such as lactic acid, HMF, levulinic acid, furfural, MMHB, and the like....

  16. C4.5 programs for machine learning

    CERN Document Server

    Quinlan, J Ross

    1992-01-01

    Classifier systems play a major role in machine learning and knowledge-based systems, and Ross Quinlan's work on ID3 and C4.5 is widely acknowledged to have made some of the most significant contributions to their development. This book is a complete guide to the C4.5 system as implemented in C for the UNIX environment. It contains a comprehensive guide to the system's use , the source code (about 8,800 lines), and implementation notes. The source code and sample datasets are also available for download (see below). C4.5 starts with large sets of cases belonging to known classes. The cases,

  17. Can miscanthus C4 photosynthesis compete with festulolium C3 photosynthesis in a temperate climate?

    DEFF Research Database (Denmark)

    Jiao, Xiurong; Kørup, Kirsten; Andersen, Mathias Neumann

    2017-01-01

    conditions and when the temperature was raised again. Therefore, this genotype could be useful for breeding new varieties with an improved cold tolerance vis-a-vis Hornum, and be valuable in broadening the genetic diversity of miscanthus for more widespread cultivation in temperate climates.......Miscanthus, a perennial grass with C4 photosynthesis, is regarded as a promising energy crop due to its high biomass productivity. Compared with other C4 species, most miscanthus genotypes have high cold tolerances at 14 °C. However, in temperate climates, temperatures below 14 °C are common...

  18. Aerial energetic residue data from JBER C4 testing

    Data.gov (United States)

    U.S. Environmental Protection Agency — Aerially-collected energetic residues from surface detonation of C4. This dataset is associated with the following publication: Walsh, M., B. Gullett, M. Walsh, M....

  19. C4 photosynthetic machinery: insights from maize chloroplast proteomics

    Directory of Open Access Journals (Sweden)

    Qi eZhao

    2013-04-01

    Full Text Available C4 plants exhibit much higher CO2 assimilation rates than C3 plants. The specialized differentiation of mesophyll cell (M and bundle sheath cell (BS type chloroplasts is unique to C4 plants and improves photosynthesis efficiency. Maize (Zea mays is an important crop and model with C4 photosynthetic machinery. Current high-throughput quantitative proteomics approaches (e.g., 2DE, iTRAQ, and shotgun proteomics have been employed to investigate maize chloroplast structure and function. These proteomic studies have provided valuable information on C4 chloroplast protein components, photosynthesis, and other metabolic mechanisms underlying chloroplast biogenesis, stromal and membrane differentiation, as well as response to salinity, high/low temperature, and light stress. This review presents an overview of proteomics advances in maize chloroplast biology.

  20. Insights into C4 metabolism from comparative deep sequencing.

    Science.gov (United States)

    Burgess, Steven J; Hibberd, Julian M

    2015-06-01

    C4 photosynthesis suppresses the oxygenation activity of Ribulose Bisphosphate Carboxylase Oxygenase and so limits photorespiration. Although highly complex, it is estimated to have evolved in 66 plant lineages, with the vast majority lacking sequenced genomes. Transcriptomics has recently initiated assessments of the degree to which transcript abundance differs between C3 and C4 leaves, identified novel components of C4 metabolism, and also led to mathematical models explaining the repeated evolution of this complex phenotype. Evidence is accumulating that this complex and convergent phenotype is partly underpinned by parallel evolution of structural genes, but also regulatory elements in both cis and trans. Furthermore, it appears that initial events associated with acquisition of C4 traits likely represent evolutionary exaptations related to non-photosynthetic processes. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Physiological advantages of C4 grasses in the field: a comparative experiment demonstrating the importance of drought.

    Science.gov (United States)

    Taylor, Samuel H; Ripley, Brad S; Martin, Tarryn; De-Wet, Leigh-Ann; Woodward, F Ian; Osborne, Colin P

    2014-06-01

    Global climate change is expected to shift regional rainfall patterns, influencing species distributions where they depend on water availability. Comparative studies have demonstrated that C4 grasses inhabit drier habitats than C3 relatives, but that both C3 and C4 photosynthesis are susceptible to drought. However, C4 plants may show advantages in hydraulic performance in dry environments. We investigated the effects of seasonal variation in water availability on leaf physiology, using a common garden experiment in the Eastern Cape of South Africa to compare 12 locally occurring grass species from C4 and C3 sister lineages. Photosynthesis was always higher in the C4 than C3 grasses across every month, but the difference was not statistically significant during the wettest months. Surprisingly, stomatal conductance was typically lower in the C3 than C4 grasses, with the peak monthly average for C3 species being similar to that of C4 leaves. In water-limited, rain-fed plots, the photosynthesis of C4 leaves was between 2.0 and 7.4 μmol m(-2) s(-1) higher, stomatal conductance almost double, and transpiration 60% higher than for C3 plants. Although C4 average instantaneous water-use efficiencies were higher (2.4-8.1 mmol mol(-1)) than C3 averages (0.7-6.8 mmol mol(-1)), differences were not as great as we expected and were statistically significant only as drought became established. Photosynthesis declined earlier during drought among C3 than C4 species, coincident with decreases in stomatal conductance and transpiration. Eventual decreases in photosynthesis among C4 plants were linked with declining midday leaf water potentials. However, during the same phase of drought, C3 species showed significant decreases in hydrodynamic gradients that suggested hydraulic failure. Thus, our results indicate that stomatal and hydraulic behaviour during drought enhances the differences in photosynthesis between C4 and C3 species. We suggest that these drought responses are

  2. Small passenger car transmission test; Ford C4 transmission

    Science.gov (United States)

    Bujold, M. P.

    1980-01-01

    A 1979 Ford C4 automatic transmission was tested per a passenger car automatic transmission test code (SAE J651b) which required drive performance, coast performance, and no load test conditions. Under these test conditions, the transmission attained maximum efficiencies in the mid-eighty percent range for both drive performance tests and coast performance tests. The major results of this test (torque, speed, and efficiency curves) are presented. Graphs map the complete performance characteristics for the Ford C4 transmission.

  3. Mycorrhizal Symbiotic Efficiency on C3 and C4 Plants under Salinity Stress - A Meta-Analysis.

    Science.gov (United States)

    Chandrasekaran, Murugesan; Kim, Kiyoon; Krishnamoorthy, Ramasamy; Walitang, Denver; Sundaram, Subbiah; Joe, Manoharan M; Selvakumar, Gopal; Hu, Shuijin; Oh, Sang-Hyon; Sa, Tongmin

    2016-01-01

    A wide range of C3 and C4 plant species could acclimatize and grow under the impact of salinity stress. Symbiotic relationship between plant roots and arbuscular mycorrhizal fungi (AMF) are widespread and are well known to ameliorate the influence of salinity stress on agro-ecosystem. In the present study, we sought to understand the phenomenon of variability on AMF symbiotic relationship on saline stress amelioration in C3 and C4 plants. Thus, the objective was to compare varied mycorrhizal symbiotic relationship between C3 and C4 plants in saline conditions. To accomplish the above mentioned objective, we conducted a random effects models meta-analysis across 60 published studies. An effect size was calculated as the difference in mycorrhizal responses between the AMF inoculated plants and its corresponding control under saline conditions. Responses were compared between (i) identity of AMF species and AMF inoculation, (ii) identity of host plants (C3 vs. C4) and plant functional groups, (iii) soil texture and level of salinity and (iv) experimental condition (greenhouse vs. field). Results indicate that both C3 and C4 plants under saline condition responded positively to AMF inoculation, thereby overcoming the predicted effects of symbiotic efficiency. Although C3 and C4 plants showed positive effects under low (EC 8 ds/m) saline conditions, C3 plants showed significant effects for mycorrhizal inoculation over C4 plants. Among the plant types, C4 annual and perennial plants, C4 herbs and C4 dicot had a significant effect over other counterparts. Between single and mixed AMF inoculants, single inoculants Rhizophagus irregularis had a positive effect on C3 plants whereas Funneliformis mosseae had a positive effect on C4 plants than other species. In all of the observed studies, mycorrhizal inoculation showed positive effects on shoot, root and total biomass, and in nitrogen, phosphorous and potassium (K) uptake. However, it showed negative effects in sodium (Na

  4. Mycorrhizal Symbiotic Efficiency on C3 and C4 Plants under Salinity Stress – A Meta-Analysis

    Science.gov (United States)

    Chandrasekaran, Murugesan; Kim, Kiyoon; Krishnamoorthy, Ramasamy; Walitang, Denver; Sundaram, Subbiah; Joe, Manoharan M.; Selvakumar, Gopal; Hu, Shuijin; Oh, Sang-Hyon; Sa, Tongmin

    2016-01-01

    A wide range of C3 and C4 plant species could acclimatize and grow under the impact of salinity stress. Symbiotic relationship between plant roots and arbuscular mycorrhizal fungi (AMF) are widespread and are well known to ameliorate the influence of salinity stress on agro-ecosystem. In the present study, we sought to understand the phenomenon of variability on AMF symbiotic relationship on saline stress amelioration in C3 and C4 plants. Thus, the objective was to compare varied mycorrhizal symbiotic relationship between C3 and C4 plants in saline conditions. To accomplish the above mentioned objective, we conducted a random effects models meta-analysis across 60 published studies. An effect size was calculated as the difference in mycorrhizal responses between the AMF inoculated plants and its corresponding control under saline conditions. Responses were compared between (i) identity of AMF species and AMF inoculation, (ii) identity of host plants (C3 vs. C4) and plant functional groups, (iii) soil texture and level of salinity and (iv) experimental condition (greenhouse vs. field). Results indicate that both C3 and C4 plants under saline condition responded positively to AMF inoculation, thereby overcoming the predicted effects of symbiotic efficiency. Although C3 and C4 plants showed positive effects under low (EC 8 ds/m) saline conditions, C3 plants showed significant effects for mycorrhizal inoculation over C4 plants. Among the plant types, C4 annual and perennial plants, C4 herbs and C4 dicot had a significant effect over other counterparts. Between single and mixed AMF inoculants, single inoculants Rhizophagus irregularis had a positive effect on C3 plants whereas Funneliformis mosseae had a positive effect on C4 plants than other species. In all of the observed studies, mycorrhizal inoculation showed positive effects on shoot, root and total biomass, and in nitrogen, phosphorous and potassium (K) uptake. However, it showed negative effects in sodium (Na

  5. Phenology and productivity of C3 and C4 grasslands in Hawaii.

    Directory of Open Access Journals (Sweden)

    Stephanie Pau

    Full Text Available Grasslands account for a large proportion of global terrestrial productivity and play a critical role in carbon and water cycling. Within grasslands, photosynthetic pathway is an important functional trait yielding different rates of productivity along environmental gradients. Recently, C3-C4 sorting along spatial environmental gradients has been reassessed by controlling for confounding traits in phylogenetically structured comparisons. C3 and C4 grasses should sort along temporal environmental gradients as well, resulting in differing phenologies and growing season lengths. Here we use 10 years of satellite data (NDVI to examine the phenology and greenness (as a proxy for productivity of C3 and C4 grass habitats, which reflect differences in both environment and plant physiology. We perform phylogenetically structured comparisons based on 3,595 digitized herbarium collections of 152 grass species across the Hawaiian Islands. Our results show that the clade identity of grasses captures differences in their habitats better than photosynthetic pathway. Growing season length (GSL and associated productivity (GSP were not significantly different when considering photosynthetic type alone, but were indeed different when considering photosynthetic type nested within clade. The relationship between GSL and GSP differed most strongly between C3 clade habitats, and not between C3-C4 habitats. Our results suggest that accounting for the interaction between phylogeny and photosynthetic pathway can help improve predictions of productivity, as commonly used C3-C4 classifications are very broad and appear to mask important diversity in grassland ecosystem functions.

  6. A generalized stoichiometric model of C3, C2, C2+C4, and C4 photosynthetic metabolism.

    OpenAIRE

    Bellasio, C.

    2016-01-01

    The goal of suppressing photorespiration in crops to maximize assimilation and yield is stimulating considerable interest among researchers looking to bioengineer carbon-concentrating mechanisms into C3 plants. However, detailed quantification of the biochemical activities in the bundle sheath is lacking. This work presents a general stoichiometric model for C3, C2, C2+C4, and C4 assimilation (SMA) in which energetics, metabolite traffic, and the different decarboxylating enzymes (NAD-depende...

  7. Photosynthesis of C3, C3–C4, and C4 grasses at glacial CO2

    OpenAIRE

    Pinto, Harshini; Sharwood, Robert E.; Tissue, David T.; Ghannoum, Oula

    2014-01-01

    Most physiology comparisons of C3 and C4 plants are made under current or elevated concentrations of atmospheric CO2 which do not reflect the low CO2 environment under which C4 photosynthesis has evolved. Accordingly, photosynthetic nitrogen (PNUE) and water (PWUE) use efficiency, and the activity of the photosynthetic carboxylases [Rubisco and phosphoenolpyruvate carboxylase (PEPC)] and decarboxylases [NADP-malic enzyme (NADP-ME) and phosphoenolpyruvate carboxykinase (PEP-CK)] were compared ...

  8. Sustainable Separations of C4 -Hydrocarbons by Using Microporous Materials.

    Science.gov (United States)

    Gehre, Mascha; Guo, Zhiyong; Rothenberg, Gadi; Tanase, Stefania

    2017-10-23

    Petrochemical refineries must separate hydrocarbon mixtures on a large scale for the production of fuels and chemicals. Typically, these hydrocarbons are separated by distillation, which is extremely energy intensive. This high energy cost can be mitigated by developing materials that can enable efficient adsorptive separation. In this critical review, the principles of adsorptive separation are outlined, and then the case for C4 separations by using zeolites and metal-organic frameworks (MOFs) is examined. By analyzing both experimental and theoretical studies, the challenges and opportunities in C4 separation are outlined, with a focus on the separation mechanisms and structure-selectivity correlations. Zeolites are commonly used as adsorbents and, in some cases, can separate C4 mixtures well. The pore sizes of eight-membered-ring zeolites, for example, are in the order of the kinetic diameters of C4 isomers. Although zeolites have the advantage of a rigid and highly stable structure, this is often difficult to functionalize. MOFs are attractive candidates for hydrocarbon separation because their pores can be tailored to optimize the adsorbate-adsorbent interactions. MOF-5 and ZIF-7 show promising results in separating all C4 isomers, but breakthrough experiments under industrial conditions are needed to confirm these results. Moreover, the flexibility of the MOF structures could hamper their application under industrial conditions. Adsorptive separation is a promising viable alternative and it is likely to play an increasingly important role in tomorrow's refineries. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Ion chemistry in octafluorocyclobutane, c-C 4F 8

    Science.gov (United States)

    Jiao, C. Q.; Garscadden, A.; Haaland, P. D.

    1998-11-01

    Cross-sections for electron impact ionization of octafluorocyclobutane ( c-C 4F 8) have been measured from 10 to 200 eV by Fourier transform mass spectrometry. No parent ion is observed, and over half of the dissociative ionization yields C 2F 4+ and C 3F 5+. Eleven other fluorocarbon cations are produced with smaller cross-sections, giving a total ionization cross-section of (1.6±0.2)×10 -15 cm 2 between 80 and 200 eV. Only CF 2+ and C 2F 3+ react further with the parent molecule to yield C 3F 5+ as the primary product. No evidence of cationic polymerization was found. F - and C 4F 8- are formed by electron attachment at energies below 10 eV, but neither reacts further with c-C 4F 8.

  10. Plastid transport and metabolism of C3 and C4 plants--comparative analysis and possible biotechnological exploitation.

    Science.gov (United States)

    Weber, Andreas P M; von Caemmerer, Susanne

    2010-06-01

    Recent progress in genomics has provided complete or near complete genome sequences of several C(3) (e.g. Arabidopsis, rice, and poplar) and C(4) (e.g. sorghum and maize) plant species. These genome sequences enabled comparative quantitative proteomic and transcriptomic analyses of C(3) and C(4) plants, in particular of their chloroplasts. Such analyses have revealed a comprehensive picture of the distribution of C(4) pathway components between bundle sheath and mesophyll cell chloroplasts and they permitted the prediction of novel pathway components. A comprehensive understanding of the C(4) photosynthetic mechanism is required for the transfer of C(4)-like photosynthesis into C(3) crop plants, such as rice. Copyright 2010. Published by Elsevier Ltd.

  11. Enzymatic Kinetic Properties of the Lactate Dehydrogenase Isoenzyme C4 of the Plateau Pika (Ochotona curzoniae

    Directory of Open Access Journals (Sweden)

    Yang Wang

    2016-01-01

    Full Text Available Testis-specific lactate dehydrogenase (LDH-C4 is one of the lactate dehydrogenase (LDH isozymes that catalyze the terminal reaction of pyruvate to lactate in the glycolytic pathway. LDH-C4 in mammals was previously thought to be expressed only in spermatozoa and testis and not in other tissues. Plateau pika (Ochotona curzoniae belongs to the genus Ochotona of the Ochotonidea family. It is a hypoxia-tolerant species living in remote mountain areas at altitudes of 3000–5000 m above sea level on the Qinghai-Tibet Plateau. Surprisingly, Ldh-c is expressed not only in its testis and sperm, but also in somatic tissues of plateau pika. To shed light on the function of LDH-C4 in somatic cells, Ldh-a, Ldh-b, and Ldh-c of plateau pika were subcloned into bacterial expression vectors. The pure enzymes of Lactate Dehydrogenase A4 (LDH-A4, Lactate Dehydrogenase B4 (LDH-B4, and LDH-C4 were prepared by a series of expression and purification processes, and the three enzymes were identified by the method of sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE and native polyacrylamide gel electrophoresis (PAGE. The enzymatic kinetics properties of these enzymes were studied by Lineweaver-Burk double-reciprocal plots. The results showed the Michaelis constant (Km of LDH-C4 for pyruvate and lactate was 0.052 and 4.934 mmol/L, respectively, with an approximate 90 times higher affinity of LDH-C4 for pyruvate than for lactate. At relatively high concentrations of lactate, the inhibition constant (Ki of the LDH isoenzymes varied: LDH-A4 (Ki = 26.900 mmol/L, LDH-B4 (Ki = 23.800 mmol/L, and LDH-C4 (Ki = 65.500 mmol/L. These data suggest that inhibition of lactate by LDH-A4 and LDH-B4 were stronger than LDH-C4. In light of the enzymatic kinetics properties, we suggest that the plateau pika can reduce reliance on oxygen supply and enhance its adaptation to the hypoxic environments due to increased anaerobic glycolysis by LDH-C4.

  12. The Metabolite Pathway between Bundle Sheath and Mesophyll: Quantification of Plasmodesmata in Leaves of C3 and C4 Monocots.

    Science.gov (United States)

    Danila, Florence R; Quick, William Paul; White, Rosemary G; Furbank, Robert T; von Caemmerer, Susanne

    2016-06-01

    C4 photosynthesis is characterized by a CO2-concentrating mechanism between mesophyll (M) and bundle sheath (BS) cells of leaves. This generates high metabolic fluxes between these cells, through interconnecting plasmodesmata (PD). Quantification of these symplastic fluxes for modeling studies requires accurate quantification of PD, which has proven difficult using transmission electron microscopy. Our new quantitative technique combines scanning electron microscopy and 3D immunolocalization in intact leaf tissues to compare PD density on cell interfaces in leaves of C3 (rice [Oryza sativa] and wheat [Triticum aestivum]) and C4 (maize [Zea mays] and Setaria viridis) monocot species. Scanning electron microscopy quantification of PD density revealed that C4 species had approximately twice the number of PD per pitfield area compared with their C3 counterparts. 3D immunolocalization of callose at pitfields using confocal microscopy showed that pitfield area per M-BS interface area was 5 times greater in C4 species. Thus, the two C4 species had up to nine times more PD per M-BS interface area (S. viridis, 9.3 PD µm(-2); maize, 7.5 PD µm(-2); rice 1.0 PD µm(-2); wheat, 2.6 PD µm(-2)). Using these anatomical data and measured photosynthetic rates in these C4 species, we have now calculated symplastic C4 acid flux per PD across the M-BS interface. These quantitative data are essential for modeling studies and gene discovery strategies needed to introduce aspects of C4 photosynthesis to C3 crops. © 2016 American Society of Plant Biologists. All rights reserved.

  13. Phylogenetics of the Chamaesyce clade (Euphorbia, Euphorbiaceae): reticulate evolution and long-distance dispersal in a prominent C4 lineage.

    Science.gov (United States)

    Yang, Ya; Berry, Paul E

    2011-09-01

    The Chamaesyce clade of Euphorbia is the largest lineage of C(4) plants among the eudicots, with 350 species including both narrow endemics and cosmopolitan weeds. We sampled this group worldwide to address questions about subclade relationships, the origin of C(4) photosynthesis, the evolution of weeds, and the role of hybridization and long-distance dispersal in the diversification of the group. • Two nuclear (ITS and exon 9 of EMB2765) and three chloroplast markers (matK, rpl16, and trnL-F) were sequenced for 138 ingroup and six outgroup species. Exon 9 of EMB2765 was cloned in accessions with >1% superimposed peaks. • The Chamaesyce clade is monophyletic and consists of three major subclades [1(2,3)]: (1) the Acuta clade, containing three North American species with C(3) photosynthesis and C(3)-C(4) intermediates; (2) the Peplis clade, mostly North American and entirely C(4); and (3) the Hypericifolia clade, all C(4), with both New World and Old World groups. Incongruence between chloroplast and ITS phylogenies and divergent cloned copies of EMB2765 exon 9 suggest extensive hybridization, especially in the Hawaiian Islands radiation. • The Chamaesyce clade originated in warm, arid areas of North America, where it evolved C(4) photosynthesis. From there, it diversified globally with extensive reticulate evolution and frequent long-distance dispersals. Although many species are weedy, there are numerous local adaptations to specific substrates and regional or island radiations, which have contributed to the great diversity of this group.

  14. A generalized stoichiometric model of C3, C2, C2+C4, and C4 photosynthetic metabolism.

    Science.gov (United States)

    Bellasio, Chandra

    2017-01-01

    The goal of suppressing photorespiration in crops to maximize assimilation and yield is stimulating considerable interest among researchers looking to bioengineer carbon-concentrating mechanisms into C3 plants. However, detailed quantification of the biochemical activities in the bundle sheath is lacking. This work presents a general stoichiometric model for C3, C2, C2+C4, and C4 assimilation (SMA) in which energetics, metabolite traffic, and the different decarboxylating enzymes (NAD-dependent malic enzyme, NADP-dependent malic enzyme, or phosphoenolpyruvate carboxykinase) are explicitly included. The SMA can be used to refine experimental data analysis or formulate hypothetical scenarios, and is coded in a freely available Microsoft Excel workbook. The theoretical underpinnings and general model behaviour are analysed with a range of simulations, including (i) an analysis of C3, C2, C2+C4, and C4 in operational conditions; (ii) manipulating photorespiration in a C3 plant; (iii) progressively upregulating a C2 shuttle in C3 photosynthesis; (iv) progressively upregulating a C4 cycle in C2 photosynthesis; and (v) manipulating processes that are hypothesized to respond to transient environmental inputs. Results quantify the functional trade-offs, such as the electron transport needed to meet ATP/NADPH demand, as well as metabolite traffic, inherent to different subtypes. The SMA refines our understanding of the stoichiometry of photosynthesis, which is of paramount importance for basic and applied research. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  15. Effects of climate and water balance across grasslands of varying C3 and C4 grass cover

    Science.gov (United States)

    Witwicki, Dana L.; Munson, Seth M.; Thoma, David P.

    2016-01-01

    Climate change in grassland ecosystems may lead to divergent shifts in the abundance and distribution of C3 and C4 grasses. Many studies relate mean climate conditions over relatively long time periods to plant cover, but there is still much uncertainty about how the balance of C3and C4 species will be affected by climate at a finer temporal scale than season (individual events to months). We monitored cover at five grassland sites with co-dominant C3 and C4 grass species or only dominant C3 grass species for 6 yr in national parks across the Colorado Plateau region to assess the influence of specific months of climate and water balance on changes in grass cover. C4 grass cover increased and decreased to a larger degree than C3 grass cover with extremely dry and wet consecutive years, but this response varied by ecological site. Climate and water balance explained 10–49% of the inter-annual variability of cover of C3 and C4 grasses at all sites. High precipitation in the spring and in previous year monsoon storms influenced changes in cover of C4 grasses, with measures of water balance in the same months explaining additional variability. C3 grasses in grasslands where they were dominant were influenced primarily by longer periods of climate, while C3 grasses in grasslands where they were co-dominant with C4 grasses were influenced little by climate anomalies at either short or long periods of time. Our results suggest that future changes in spring and summer climate and water balance are likely to affect cover of both C3 and C4 grasses, but cover of C4 grasses may be affected more strongly, and the degree of change will depend on soils and topography where they are growing and the timing of the growing season.

  16. Effect of Sodium Nutrition on the Ultrastructure of Chloroplasts of C4 Plants

    Science.gov (United States)

    Grof, Christopher P. L.; Johnston, Mark; Brownell, Peter F.

    1989-01-01

    Mesophyll chloroplasts from sodium-deficient compared to normal plants of the C4 species Kochia childsii and Amaranthus tricolor were found to have significantly less stacking in their grana. On the other hand, no marked difference of thylakoid arrangement between bundle sheath chloroplasts from sodium-deficient and normal plants of A. tricolor were observed. Images Figure 1 Figure 2 Figure 5 PMID:16666579

  17. The potential of C4 grasses for cellulosic biofuel production

    NARCIS (Netherlands)

    Weijde, van der R.T.; Alvim Kamei, C.L.; Torres Salvador, A.F.; Vermerris, W.; Dolstra, O.; Visser, R.G.F.; Trindade, L.M.

    2013-01-01

    With the advent of biorefinery technologies enabling plant biomass to be processed into biofuel, many researchers set out to study and improve candidate biomass crops. Many of these candidates are C4 grasses, characterized by a high productivity and resource use efficiency. In this review the

  18. Report Out of the C4I Study Group

    Science.gov (United States)

    2001-06-01

    Portugal has no problem in coupling its CAX system Visualização Gráfica do Terreno em Modelo Digital 3D (VIGRESTE) with Allied Tactical Command and...to C4ISR systems. It provides an excellent comparison and alternate viewpoint to the TRM. The TRM is more focused on information exchange, while the

  19. Characterization of a C4 maize pyruvate orthophosphate dikinase ...

    African Journals Online (AJOL)

    PRECIOUS

    2010-01-11

    Jan 11, 2010 ... affected the phenotypes of plants particularly tillers and enhanced yield of transgenic IR64 rice plants in the greenhouse. Key words: Indica rice IR64, Maize (Zea mays), photosynthesis, PPDK (pyruvate orthophosphate dikinase), C4 rice. INTRODUCTION. In order to meet the demand for food from the ...

  20. Microscale modeling of gas exchange during C4 photosythesis

    NARCIS (Netherlands)

    Retta, Moges

    2017-01-01

    Improving the efficiency of photosynthesis could contribute to better food security under an unprecedented rise in global population and climate-change. The photosynthesis pathway in C4 plants, such as maize (Zea mays L.), Miscanthus (Miscanthus x giganteus), and sugarcane (Saccharum officinarum

  1. Online CO2 and H2 O oxygen isotope fractionation allows estimation of mesophyll conductance in C4 plants, and reveals that mesophyll conductance decreases as leaves age in both C4 and C3 plants.

    Science.gov (United States)

    Barbour, Margaret M; Evans, John R; Simonin, Kevin A; von Caemmerer, Susanne

    2016-05-01

    Mesophyll conductance significantly, and variably, limits photosynthesis but we currently have no reliable method of measurement for C4 plants. An online oxygen isotope technique was developed to allow quantification of mesophyll conductance in C4 plants and to provide an alternative estimate in C3 plants. The technique is compared to an established carbon isotope method in three C3 species. Mesophyll conductance of C4 species was similar to that in the C3 species measured, and declined in both C4 and C3 species as leaves aged from fully expanded to senescing. In cotton leaves, simultaneous measurement of carbon and oxygen isotope discrimination allowed the partitioning of total conductance to the chloroplasts into cell wall and plasma membrane versus chloroplast membrane components, if CO2 was assumed to be isotopically equilibrated with cytosolic water, and the partitioning remained stable with leaf age. The oxygen isotope technique allowed estimation of mesophyll conductance in C4 plants and, when combined with well-established carbon isotope techniques, may provide additional information on mesophyll conductance in C3 plants. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  2. Studies on anatomical characters indicating C3 and C4 photosynthetic metabolism in the genus Boerhavia L. (Nyctaginaceae

    Directory of Open Access Journals (Sweden)

    Abdulwakeel Ayokun-nun Ajao

    2017-08-01

    Full Text Available The C3 and C4 photosynthetic pathways in dicotyledons were investigated with the four species of Boerhavia occurring in Nigeria using light microscopy. The study is not yet well reported on dicotyledons as done for monocotyledons. The features cross-examined were stomata index, stomata size, inter-stomatal distance, stomatal density, interveinal distance, intercellular air spaces, leaf thickness, mesophyll thickness, Kranz tissue, one cell distant count criterion, maximum lateral cell count criterion, vein density and vein distance. Based on these features, these species (B. erecta, B. coccinea and B. repens were grouped into C4 while B. diffusa was grouped as a C3 plant. In particular, interveinal distance less than 166µm and maximum lateral count ranging 2 to 6 will help in grouping C4 dicotyledons species while those that were greater than these values are useful in grouping C3 and plants.

  3. Carbon Concentrating Mechanisms & C4 Enzymes In Marine Phytoplankton

    Science.gov (United States)

    Moolna, A.; Hermoso, M.; Rickaby, R.

    2009-12-01

    Photosynthetic CO2 assimilation by marine phytoplankton is a major sink in the Earth’s carbon cycle. Understanding the molecular biogeochemistry of this carbon capture is crucial to predicting how the Earth will respond to the carbon emissions driving human-induced climate change. We are investigating the connection of phytoplankton photosynthesis to different CO2 levels using the diatom Thalassiosira weissflogii and the coccolithophores Emiliania huxleyi and Gephyrocapsa oceanica. Phytoplankton in equilibrium with present-day atmospheric CO2 levels have carbon concentrating mechanisms (CCMs) that increase their internal concentration of dissolved inorganic carbon (DIC) relative to their surrounding seawater. By acclimating cultures to seawater with quadrupled DIC availability, the CCM physiology is relaxed. This is demonstrated by resuspending the phytoplankton in CO2-free seawater and then plotting the response curve of photosynthetic O2 evolution rate against the addition of specific concentrations of DIC (Figure 1). Relaxation implies less energy used for CCMs and so more energy may be available for carbon fixation. Scanning electron micrographs of high DIC G. oceanica cultures, for example, show that the size of both the coccosphere and of individual coccoliths is unchanged; but the external shield of the coccolith extends further into the central area. This suggests an increase in calcification, with implications for carbon partition between organic and inorganic fluxes to the seafloor. Of particular interest is the possibility that C4 photosynthesis could provide a CCM for marine phytoplankton. The carbon-fixing Rubisco enzyme can only use CO2 as a substrate but, due to reaction between CO2 and H2O, most of the CO2 dissolved in seawater is actually present as HCO3-. In C4 land plants, CO2 for Rubisco is provided via a four-carbon intermediate compound generated from HCO3-; and the basic C4 machinery is found in all photosynthetic life because of

  4. Bundle-sheath leakiness in C4 photosynthesis: a careful balancing act between CO2 concentration and assimilation.

    Science.gov (United States)

    Kromdijk, Johannes; Ubierna, Nerea; Cousins, Asaph B; Griffiths, Howard

    2014-07-01

    Crop species with the C4 photosynthetic pathway are generally characterized by high productivity, especially in environmental conditions favouring photorespiration. In comparison with the ancestral C3 pathway, the biochemical and anatomical modifications of the C4 pathway allow spatial separation of primary carbon acquisition in mesophyll cells and subsequent assimilation in bundle-sheath cells. The CO2-concentrating C4 cycle has to operate in close coordination with CO2 reduction via the Calvin-Benson-Bassham (CBB) cycle in order to keep the C4 pathway energetically efficient. The gradient in CO2 concentration between bundle-sheath and mesophyll cells facilitates diffusive leakage of CO2. This rate of bundle-sheath CO2 leakage relative to the rate of phosphoenolpyruvate carboxylation (termed leakiness) has been used to probe the balance between C4 carbon acquisition and subsequent reduction as a result of environmental perturbations. When doing so, the correct choice of equations to derive leakiness from stable carbon isotope discrimination (Δ(13)C) during gas exchange is critical to avoid biased results. Leakiness responses to photon flux density, either short-term (during measurements) or long-term (during growth and development), can have important implications for C4 performance in understorey light conditions. However, recent reports show leakiness to be subject to considerable acclimation. Additionally, the recent discovery of two decarboxylating C4 cycles operating in parallel in Zea mays suggests that flexibility in the transported C4 acid and associated decarboxylase could also aid in maintaining C4/CBB balance in a changing environment. In this paper, we review improvements in methodology to estimate leakiness, synthesize reports on bundle-sheath leakiness, discuss different interpretations, and highlight areas where future research is necessary. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology

  5. de la fotosíntesis C4

    Directory of Open Access Journals (Sweden)

    J. C. Raya-Pérez

    2008-01-01

    Full Text Available La fotosíntesis C4 surgió hace unos 7-5 millones de años y tiene un origen polifilético. La disminución en la concentración atmosférica de CO2 a menos de 500 partes por millón (ppm propició la aparición de un mecanismo para concentrar este gas en la zona donde actúa la Rubisco (ribulosa bifosfato carboxilasa/oxigenasa, evitando así su actividad de oxigenasa. El análisis de los genes que codifican para las enzimas usadas en la vía C4, así como la caracterización bioquímica de algunas de estas enzimas, permiten entrever algunos de los cambios que han sufrido a fin de adaptarse a una nueva función, la de concentrar el CO2 a fin de que sea utilizado por la Rubisco.

  6. Modification of Photosystem I Light Harvesting of Bundle-Sheath Chloroplasts Occurred during the Evolution of NADP-Malic Enzyme C4 Photosynthesis.

    Science.gov (United States)

    Pfundel, E.; Pfeffer, M.

    1997-05-01

    Low-temperature emission spectra and excitation spectra for chlorophyll fluorescence were recorded from leaves of species of the genus Flaveria (Asteraceae) with C3, C3-C4-intermediate, C4-like, and C4 photosynthesis. Among the latter two groups, high chlorophyll b absorption was observed in excitation spectra for photosystem I (PSI) fluorescence. By comparing leaf data with those from isolated chloroplast fractions, the high chlorophyll b absorption was attributed to the specific properties of the bundle-sheath chloroplasts in leaves from C4 plants. The deconvolution of the PSI excitation spectra and the use of a model revealed that the contribution of photosystem II absorption to the functional antenna of PSI was markedly increased in leaves from three of the five C4-like and C4 species investigated in detail. The two other species exhibited normal, C3-like light-harvesting properties of PSI. The former species are known for efficient carbon assimilation, the latter for decreased efficiencies of carbon assimilation. It is concluded that photosystem II becomes a substantial part of the functional PSI antenna late in the evolution of C4 photosynthesis, and that the composite antenna optimizes the light-harvesting of PSI in bundle-sheath chloroplasts to meet the energy requirements of C4 photosynthesis.

  7. Modelling metabolic evolution on phenotypic fitness landscapes: a case study on C4 photosynthesis.

    Science.gov (United States)

    Heckmann, David

    2015-12-01

    How did the complex metabolic systems we observe today evolve through adaptive evolution? The fitness landscape is the theoretical framework to answer this question. Since experimental data on natural fitness landscapes is scarce, computational models are a valuable tool to predict landscape topologies and evolutionary trajectories. Careful assumptions about the genetic and phenotypic features of the system under study can simplify the design of such models significantly. The analysis of C4 photosynthesis evolution provides an example for accurate predictions based on the phenotypic fitness landscape of a complex metabolic trait. The C4 pathway evolved multiple times from the ancestral C3 pathway and models predict a smooth 'Mount Fuji' landscape accordingly. The modelled phenotypic landscape implies evolutionary trajectories that agree with data on modern intermediate species, indicating that evolution can be predicted based on the phenotypic fitness landscape. Future directions will have to include structural changes of metabolic fitness landscape structure with changing environments. This will not only answer important evolutionary questions about reversibility of metabolic traits, but also suggest strategies to increase crop yields by engineering the C4 pathway into C3 plants. © 2015 Authors; published by Portland Press Limited.

  8. Laboratory detection of the C3N an C4H free radicals

    Science.gov (United States)

    Gottlieb, C. A.; Gottlieb, E. W.; Thaddeus, P.; Kawamura, H.

    1983-01-01

    The millimeter-wave spectra of the linear carbon chain free radicals C3N and C4H, first identified in IRC + 10216 and hitherto observed only in a few astronomical sources, have been detected with a Zeeman-modulated spectrometer in laboratory glow discharges through low pressure flowing mixtures of N2 + HC3N and He + HCCH, respectively. Four successive rotational transitions between 168 and 198 GHz have been measured for C3N, and five rotational transitions between 143 and 200 GHz for C4H; each is a well-resolved spin doublet owing to the unpaired electron present in both species. Precise values for the rotational, centrifugal distortion, and spin doubling constants have been obtained, which, with hyperfine constants derived from observations of the lower rotational transitions in the astronomical source TMC 1, allow all the rotational transitions of C3N and C4H at frequencies less than 300 GHz to be calculated to an absolute accuracy exceeding 1 ppm.

  9. Deep evolutionary comparison of gene expression identifies parallel recruitment of trans-factors in two independent origins of C4 photosynthesis.

    Directory of Open Access Journals (Sweden)

    Sylvain Aubry

    2014-06-01

    Full Text Available With at least 60 independent origins spanning monocotyledons and dicotyledons, the C4 photosynthetic pathway represents one of the most remarkable examples of convergent evolution. The recurrent evolution of this highly complex trait involving alterations to leaf anatomy, cell biology and biochemistry allows an increase in productivity by ∼ 50% in tropical and subtropical areas. The extent to which separate lineages of C4 plants use the same genetic networks to maintain C4 photosynthesis is unknown. We developed a new informatics framework to enable deep evolutionary comparison of gene expression in species lacking reference genomes. We exploited this to compare gene expression in species representing two independent C4 lineages (Cleome gynandra and Zea mays whose last common ancestor diverged ∼ 140 million years ago. We define a cohort of 3,335 genes that represent conserved components of leaf and photosynthetic development in these species. Furthermore, we show that genes encoding proteins of the C4 cycle are recruited into networks defined by photosynthesis-related genes. Despite the wide evolutionary separation and independent origins of the C4 phenotype, we report that these species use homologous transcription factors to both induce C4 photosynthesis and to maintain the cell specific gene expression required for the pathway to operate. We define a core molecular signature associated with leaf and photosynthetic maturation that is likely shared by angiosperm species derived from the last common ancestor of the monocotyledons and dicotyledons. We show that deep evolutionary comparisons of gene expression can reveal novel insight into the molecular convergence of highly complex phenotypes and that parallel evolution of trans-factors underpins the repeated appearance of C4 photosynthesis. Thus, exploitation of extant natural variation associated with complex traits can be used to identify regulators. Moreover, the transcription factors

  10. Deep Evolutionary Comparison of Gene Expression Identifies Parallel Recruitment of Trans-Factors in Two Independent Origins of C4 Photosynthesis

    Science.gov (United States)

    Kümpers, Britta M. C.; Smith-Unna, Richard D.; Hibberd, Julian M.

    2014-01-01

    With at least 60 independent origins spanning monocotyledons and dicotyledons, the C4 photosynthetic pathway represents one of the most remarkable examples of convergent evolution. The recurrent evolution of this highly complex trait involving alterations to leaf anatomy, cell biology and biochemistry allows an increase in productivity by ∼50% in tropical and subtropical areas. The extent to which separate lineages of C4 plants use the same genetic networks to maintain C4 photosynthesis is unknown. We developed a new informatics framework to enable deep evolutionary comparison of gene expression in species lacking reference genomes. We exploited this to compare gene expression in species representing two independent C4 lineages (Cleome gynandra and Zea mays) whose last common ancestor diverged ∼140 million years ago. We define a cohort of 3,335 genes that represent conserved components of leaf and photosynthetic development in these species. Furthermore, we show that genes encoding proteins of the C4 cycle are recruited into networks defined by photosynthesis-related genes. Despite the wide evolutionary separation and independent origins of the C4 phenotype, we report that these species use homologous transcription factors to both induce C4 photosynthesis and to maintain the cell specific gene expression required for the pathway to operate. We define a core molecular signature associated with leaf and photosynthetic maturation that is likely shared by angiosperm species derived from the last common ancestor of the monocotyledons and dicotyledons. We show that deep evolutionary comparisons of gene expression can reveal novel insight into the molecular convergence of highly complex phenotypes and that parallel evolution of trans-factors underpins the repeated appearance of C4 photosynthesis. Thus, exploitation of extant natural variation associated with complex traits can be used to identify regulators. Moreover, the transcription factors that are shared by

  11. Histone Acetylation Modifications Affect Tissue-Dependent Expression of Poplar Homologs of C4 Photosynthetic Enzyme Genes

    Directory of Open Access Journals (Sweden)

    Yuan Li

    2017-06-01

    Full Text Available Histone modifications play important roles in regulating the expression of C4 photosynthetic genes. Given that all enzymes required for the C4 photosynthesis pathway are present in C3 plants, it has been hypothesized that this expression regulatory mechanism has been conserved. However, the relationship between histone modification and the expression of homologs of C4 photosynthetic enzyme genes has not been well determined in C3 plants. In the present study, we cloned nine hybrid poplar (Populus simonii × Populus nigra homologs of maize (Zea mays C4 photosynthetic enzyme genes, carbonic anhydrase (CA, pyruvate orthophosphate dikinase (PPDK, phosphoenolpyruvate carboxykinase (PCK, and phosphoenolpyruvate carboxylase (PEPC, and investigated the correlation between the expression levels of these genes and the levels of promoter histone acetylation modifications in four vegetative tissues. We found that poplar homologs of C4 homologous genes had tissue-dependent expression patterns that were mostly well-correlated with the level of histone acetylation modification (H3K9ac and H4K5ac determined by chromatin immunoprecipitation assays. Treatment with the histone deacetylase inhibitor trichostatin A further confirmed the role of histone acetylation in the regulation of the nine target genes. Collectively, these results suggest that both H3K9ac and H4K5ac positively regulate the tissue-dependent expression pattern of the PsnCAs, PsnPPDKs, PsnPCKs, and PsnPEPCs genes and that this regulatory mechanism seems to be conserved among the C3 and C4 species. Our findings provide new insight that will aid efforts to modify the expression pattern of these homologs of C4 genes to engineer C4 plants from C3 plants.

  12. Interaction between C 4 barnyard grass and C 3 upland rice under elevated CO 2: Impact of mycorrhizae

    Science.gov (United States)

    Tang, Jianjun; Xu, Liming; Chen, Xin; Hu, Shuijin

    2009-03-01

    Atmospheric CO 2 enrichment may impact arbuscular mycorrhizae (AM) development and function, which could have subsequent effects on host plant species interactions by differentially affecting plant nutrient acquisition. However, direct evidence illustrating this scenario is limited. We examined how elevated CO 2 affects plant growth and whether mycorrhizae mediate interactions between C 4 barnyard grass ( Echinochloa crusgalli (L.) Beauv.) and C 3 upland rice ( Oryza sativa L.) in a low nutrient soil. The monocultures and combinations with or without mycorrhizal inoculation were grown at ambient (400 ± 20 μmol mol -1) and elevated CO 2 (700 ± 20 μmol mol -1) levels. The 15N isotope tracer was introduced to quantify the mycorrhizally mediated N acquisition of plants. Elevated CO 2 stimulated the growth of C 3 upland rice but not that of C 4 barnyard grass under monoculture. Elevated CO 2 also increased mycorrhizal colonization of C 4 barnyard grass but did not affect mycorrhizal colonization of C 3 upland rice. Mycorrhizal inoculation increased the shoot biomass ratio of C 4 barnyard grass to C 3 upland rice under both CO 2 concentrations but had a greater impact under the elevated than ambient CO 2 level. Mycorrhizae decreased relative interaction index (RII) of C 3 plants under both ambient and elevated CO 2, but mycorrhizae increased RII of C 4 plants only under elevated CO 2. Elevated CO 2 and mycorrhizal inoculation enhanced 15N and total N and P uptake of C 4 barnyard grass in mixture but had no effects on N and P acquisition of C 3 upland rice, thus altering the distribution of N and P between the species in mixture. These results implied that CO 2 stimulation of mycorrhizae and their nutrient acquisition may impact competitive interaction of C 4 barnyard grass and C 3 upland rice under future CO 2 scenarios.

  13. Differences in drought sensitivities and photosynthetic limitations between co-occurring C3 and C4 (NADP-ME) Panicoid grasses.

    Science.gov (United States)

    Ripley, Brad; Frole, Kristen; Gilbert, Matthew

    2010-03-01

    The success of C4 plants lies in their ability to attain greater efficiencies of light, water and nitrogen use under high temperature, providing an advantage in arid, hot environments. However, C4 grasses are not necessarily less sensitive to drought than C3 grasses and are proposed to respond with greater metabolic limitations, while the C3 response is predominantly stomatal. The aims of this study were to compare the drought and recovery responses of co-occurring C3 and C4 NADP-ME grasses from the subfamily Panicoideae and to determine stomatal and metabolic contributions to the observed response. Six species of locally co-occurring grasses, C3) species Alloteropsis semialata subsp. eckloniana, Panicum aequinerve and Panicum ecklonii, and C4 (NADP-ME) species Heteropogon contortus, Themeda triandra and Tristachya leucothrix, were established in pots then subjected to a controlled drought followed by re-watering. Water potentials, leaf gas exchange and the response of photosynthetic rate to internal CO2 concentrations were determined on selected occasions during the drought and re-watering treatments and compared between species and photosynthetic types. Leaves of C4 species of grasses maintained their photosynthetic advantage until water deficits became severe, but lost their water-use advantage even under conditions of mild drought. Declining C4 photosynthesis with water deficit was mainly a consequence of metabolic limitations to CO2 assimilation, whereas, in the C3 species, stomatal limitations had a prevailing role in the drought-induced decrease in photosynthesis. The drought-sensitive metabolism of the C4 plants could explain the observed slower recovery of photosynthesis on re-watering, in comparison with C3 plants which recovered a greater proportion of photosynthesis through increased stomatal conductance. Within the Panicoid grasses, C4 (NADP-ME) species are metabolically more sensitive to drought than C3 species and recover more slowly from drought.

  14. C4 plants as biofuel feedstocks: optimising biomass production and feedstock quality from a lignocellulosic perspective.

    Science.gov (United States)

    Byrt, Caitlin S; Grof, Christopher P L; Furbank, Robert T

    2011-02-01

    The main feedstocks for bioethanol are sugarcane (Saccharum officinarum) and maize (Zea mays), both of which are C(4) grasses, highly efficient at converting solar energy into chemical energy, and both are food crops. As the systems for lignocellulosic bioethanol production become more efficient and cost effective, plant biomass from any source may be used as a feedstock for bioethanol production. Thus, a move away from using food plants to make fuel is possible, and sources of biomass such as wood from forestry and plant waste from cropping may be used. However, the bioethanol industry will need a continuous and reliable supply of biomass that can be produced at a low cost and with minimal use of water, fertilizer and arable land. As many C(4) plants have high light, water and nitrogen use efficiency, as compared with C(3) species, they are ideal as feedstock crops. We consider the productivity and resource use of a number of candidate plant species, and discuss biomass 'quality', that is, the composition of the plant cell wall. © 2011 Institute of Botany, Chinese Academy of Sciences.

  15. Comparative proteomics of chloroplast envelopes from C3 and C4 plants reveals specific adaptations of the plastid envelope to C4 photosynthesis and candidate proteins required for maintaining C4 metabolite fluxes.

    Science.gov (United States)

    Bräutigam, Andrea; Hoffmann-Benning, Susanne; Hofmann-Benning, Susanne; Weber, Andreas P M

    2008-09-01

    C(4) plants have up to 10-fold higher apparent CO(2) assimilation rates than the most productive C(3) plants. This requires higher fluxes of metabolic intermediates across the chloroplast envelope membranes of C(4) plants in comparison with those of C(3) plants. In particular, the fluxes of metabolites involved in the biochemical inorganic carbon pump of C(4) plants, such as malate, pyruvate, oxaloacetate, and phosphoenolpyruvate, must be considerably higher in C(4) plants because they exceed the apparent rate of photosynthetic CO(2) assimilation, whereas they represent relatively minor fluxes in C(3) plants. While the enzymatic steps involved in the C(4) biochemical inorganic carbon pump have been studied in much detail, little is known about the metabolite transporters in the envelope membranes of C(4) chloroplasts. In this study, we used comparative proteomics of chloroplast envelope membranes from the C(3) plant pea (Pisum sativum) and mesophyll cell chloroplast envelopes from the C(4) plant maize (Zea mays) to analyze the adaptation of the mesophyll cell chloroplast envelope proteome to the requirements of C(4) photosynthesis. We show that C(3)- and C(4)-type chloroplasts have qualitatively similar but quantitatively very different chloroplast envelope membrane proteomes. In particular, translocators involved in the transport of triosephosphate and phosphoenolpyruvate as well as two outer envelope porins are much more abundant in C(4) plants. Several putative transport proteins have been identified that are highly abundant in C(4) plants but relatively minor in C(3) envelopes. These represent prime candidates for the transport of C(4) photosynthetic intermediates, such as pyruvate, oxaloacetate, and malate.

  16. C4 plants use fluctuating light less efficiently than do C3 plants: a study of growth, photosynthesis and carbon isotope discrimination.

    Science.gov (United States)

    Kubásek, Jiří; Urban, Otmar; Šantrůček, Jiří

    2013-12-01

    Plants in the field are commonly exposed to fluctuating light intensity, caused by variable cloud cover, self-shading of leaves in the canopy and/or leaf movement due to turbulence. In contrast to C3 plant species, only little is known about the effects of dynamic light (DL) on photosynthesis and growth in C4 plants. Two C4 and two C3 monocot and eudicot species were grown under steady light or DL conditions with equal sum of daily incident photon flux. We measured leaf gas exchange, plant growth and dry matter carbon isotope discrimination to infer CO2 bundle sheath leakiness in C4 plants. The growth of all species was reduced by DL, despite only small changes in steady-state gas exchange characteristics, and this effect was more pronounced in C4 than C3 species due to lower assimilation at light transitions. This was partially attributed to increased bundle sheath leakiness in C4 plants under the simulated lightfleck conditions. We hypothesize that DL leads to imbalances in the coordination of C4 and C3 cycles and increasing leakiness, thereby decreasing the quantum efficiency of photosynthesis. In addition to their other constraints, the inability of C4 plants to efficiently utilize fluctuating light likely contributes to their absence in such environments as forest understoreys. © 2013 Scandinavian Plant Physiology Society.

  17. Active C4 Electrodes for Local Field Potential Recording Applications.

    Science.gov (United States)

    Wang, Lu; Freedman, David; Sahin, Mesut; Ünlü, M Selim; Knepper, Ronald

    2016-02-04

    Extracellular neural recording, with multi-electrode arrays (MEAs), is a powerful method used to study neural function at the network level. However, in a high density array, it can be costly and time consuming to integrate the active circuit with the expensive electrodes. In this paper, we present a 4 mm × 4 mm neural recording integrated circuit (IC) chip, utilizing IBM C4 bumps as recording electrodes, which enable a seamless active chip and electrode integration. The IC chip was designed and fabricated in a 0.13 μm BiCMOS process for both in vitro and in vivo applications. It has an input-referred noise of 4.6 μV rms for the bandwidth of 10 Hz to 10 kHz and a power dissipation of 11.25 mW at 2.5 V, or 43.9 μW per input channel. This prototype is scalable for implementing larger number and higher density electrode arrays. To validate the functionality of the chip, electrical testing results and acute in vivo recordings from a rat barrel cortex are presented.

  18. Glyphosate Resistance of C3 and C4 Weeds under Rising Atmospheric CO2.

    Science.gov (United States)

    Fernando, Nimesha; Manalil, Sudheesh; Florentine, Singarayer K; Chauhan, Bhagirath S; Seneweera, Saman

    2016-01-01

    The present paper reviews current knowledge on how changes of plant metabolism under elevated CO2 concentrations (e[CO2]) can affect the development of the glyphosate resistance of C3 and C4 weeds. Among the chemical herbicides, glyphosate, which is a non-selective and post-emergence herbicide, is currently the most widely used herbicide in global agriculture. As a consequence, glyphosate resistant weeds, particularly in major field crops, are a widespread problem and are becoming a significant challenge to future global food production. Of particular interest here it is known that the biochemical processes involved in photosynthetic pathways of C3 and C4 plants are different, which may have relevance to their competitive development under changing environmental conditions. It has already been shown that plant anatomical, morphological, and physiological changes under e[CO2] can be different, based on (i) the plant's functional group, (ii) the available soil nutrients, and (iii) the governing water status. In this respect, C3 species are likely to have a major developmental advantage under a CO2 rich atmosphere, by being able to capitalize on the overall stimulatory effect of e[CO2]. For example, many tropical weed grass species fix CO2 from the atmosphere via the C4 photosynthetic pathway, which is a complex anatomical and biochemical variant of the C3 pathway. Thus, based on our current knowledge of CO2 fixing, it would appear obvious that the development of a glyphosate-resistant mechanism would be easier under an e[CO2] in C3 weeds which have a simpler photosynthetic pathway, than for C4 weeds. However, notwithstanding this logical argument, a better understanding of the biochemical, genetic, and molecular measures by which plants develop glyphosate resistance and how e[CO2] affects these measures will be important before attempting to innovate sustainable technology to manage the glyphosate-resistant evolution of weeds under e[CO2]. Such information will be of

  19. Observations of Titan 3C-4 Transtage Fragmentation Debris

    Science.gov (United States)

    Cowardin, Heather; Seitzer, P.; Abercromby, K.; Barker, E.; Cardona, T.; Krisko, P.; Lederer, S.

    2013-01-01

    The fragmentation of a Titan 3C-4 Transtage (1968-081) on 21 February 1992 is one of only two known break-ups in or near geosynchronous orbit. The original rocket body and 24 pieces of debris are currently being tracked by the US Space Surveillance Network (SSN). The rocket body (SSN# 3432) and several of the original fragments (SSN# 25000, 25001, 30000, and 33511) were observed in survey mode during 2004-2010 using the 0.6-m Michigan Orbital DEbris Survey Telescope (MODEST) in Chile using a broad R filter. This paper will present a size distribution for all calibrated magnitude data acquired on MODEST. Size distribution plots will also be shown using historical models for small fragmentation debris (down to 10 cm) believed to be associated with the Titan break-up. In November 2010, visible broadband photometry (Johnson/Kron-Cousins BVRI) was acquired with the 0.9-m Small and Moderate Aperture Research Telescope System (SMARTS) at the Cerro Tololo Inter-American Observatory (CTIO) in Chile on several Titan fragments (SSN# 25001, 33509, 33510) and the parent rocket body. Color index data will be used to determine the fragment brightness distribution and how the data compares to spacecraft materials measured in the laboratory using similar photometric measurement techniques. In 2012, the SSN added 16 additional fragments to the catalogue. MODEST acquired magnitude data on ten Titan fragments in late 2012 and early 2013. The magnitude distribution of all the observed fragments are analyzed as a function of time. In order to better characterize the breakup fragments spectral measurements were acquired on the original rocket body and five Titan fragments using the 6.5-m Magellan telescopes at Las Campanas Observatory in Chile. The telescopic spectra are compared with laboratory acquired spectra of materials (e.g., Aluminum and various paints) and categorized based on known absorption features for spacecraft materials.

  20. Seasonal differences in photosynthesis between the C3 and C4 subspecies of Alloteropsis semialata are offset by frost and drought.

    Science.gov (United States)

    Ibrahim, Douglas G; Gilbert, Matthew E; Ripley, Brad S; Osborne, Colin P

    2008-07-01

    The regional abundance of C(4) grasses is strongly controlled by temperature, however, the role of precipitation is less clear. Progress in elucidating the direct effects of photosynthetic pathway on these climate relationships is hindered by the significant genetic divergence between major C(3) and C(4) grass lineages. We addressed this problem by examining seasonal climate responses of photosynthesis in Alloteropsis semialata, a unique grass species with both C(3) and C(4) subspecies. Experimental manipulation of rainfall in a common garden in South Africa tested the hypotheses that: (1) photosynthesis is greater in the C(4) than C(3) subspecies under high summer temperatures, but this pattern is reversed at low winter temperatures; and (2) the photosynthetic advantage of C(4) plants is enhanced during drought events. Measurements of leaf gas exchange over 2 years showed a significant photosynthetic advantage for the C(4) subspecies under irrigated conditions from spring through autumn. However, the C(4) leaves were killed by winter frost, while photosynthesis continued in the C(3) plants. Unexpectedly, the C(4) subspecies also lost its photosynthetic advantage during natural drought events, despite greater water-use efficiency under irrigated conditions. This study highlights previously unrecognized roles for climatic extremes in determining the ecological success of C(3) and C(4) grasses.

  1. Oxidation Behavior and Mechanism of Al4SiC4 in MgO-C-Al4SiC4 System

    Directory of Open Access Journals (Sweden)

    Huabai Yao

    2017-06-01

    Full Text Available Al4SiC4 powder with high purity was synthesized using the powder mixture of aluminum (Al, silicon (Si, and carbon (C at 1800 °C in argon. Their oxidation behavior and mechanism in a MgO-C-Al4SiC4 system was investigated at 1400–1600 °C. XRD, SEM, and energy dispersive spectrometry (EDS were adopted to analyze the microstructure and phase evolution. The results showed that the composition of oxidation products was closely related to the atom diffusion velocity and the compound oxide layer was generated on Al4SiC4 surface. In addition, the effect of different CO partial pressure on the oxidation of Al4SiC4 crystals was also studied by thermodynamic calculation. This work proves the great potential of Al4SiC4 in improving the MgO-C materials.

  2. The ultraviolet photochemistry of diacetylene - Direct detection of primary products of the metastable C4H2* + C4H2 reaction

    Science.gov (United States)

    Bandy, Ralph E.; Lakshminarayan, Chitra; Frost, Rex K.; Zwier, Timothy S.

    1993-01-01

    The products of diacetylene's ultraviolet photochemistry over the 245-220 nm region were directly determined in experiments where C4H2 was excited within a small reaction tube attached to a pulsed nozzle. The products formed in the collisions of C4H2* with C4H2 were subsequently ionized by vacuum UV radiation (at 118 nm) in the ion source of a time-of-flight mass spectrometer. It was found that the reaction of C4H2* with C4H2 produces C6H2 (+C2H2), C8H2 (+2H,H2), and C8H3 (+H), confirming the results of Glicker and Okabe (1987). Under certain conditions, secondary products were observed. Mechanisms for the observed reactions are proposed.

  3. 26 CFR 1.662(c)-4 - Illustration of the provisions of sections 661 and 662.

    Science.gov (United States)

    2010-04-01

    ... 26 Internal Revenue 8 2010-04-01 2010-04-01 false Illustration of the provisions of sections 661 and 662. 1.662(c)-4 Section 1.662(c)-4 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE... Which Distribute Corpus § 1.662(c)-4 Illustration of the provisions of sections 661 and 662. The...

  4. 26 CFR 1.652(c)-4 - Illustration of the provisions of sections 651 and 652.

    Science.gov (United States)

    2010-04-01

    ... 26 Internal Revenue 8 2010-04-01 2010-04-01 false Illustration of the provisions of sections 651 and 652. 1.652(c)-4 Section 1.652(c)-4 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE....652(c)-4 Illustration of the provisions of sections 651 and 652. The rules applicable to a trust...

  5. Heats of formation and thermodynamic functions for C2H, C3H, and C4H from 300 K to 6000 K

    Science.gov (United States)

    Saturno, A. F.

    1982-01-01

    A review of the energy level and heat of formation data for the species C2H, C3H, and C4H is given. The procedure for computing thermochemical data from partition function is also reviewed. Working expressions for approximate partition functions, free-energy function, enthalpy function, and heat capacity for a linear polyatomic species are presented.

  6. A specific assay for quantification of human C4c by use of an anti-C4c monoclonal antibody

    DEFF Research Database (Denmark)

    Pilely, Katrine; Skjoedt, Mikkel-Ole; Nielsen, Christian

    2014-01-01

    a mouse monoclonal antibody (mAb) that is able to detect fluid phase C4c without interference from other products generated from the complement component C4. The C4c specific mAb was tested in different enzyme-linked immunosorbent assay (ELISA) combinations with various types of in vitro activated sera......, with a mean of 0.85mg/L and a range of 0.19-2.21mg/L. We believe that the C4c specific antibody and the ELISA might be important tools in the future assessment of in vivo activation in situations where the classical or the lectin complement pathways are involved in the pathogenesis....... and samples from factor I deficient patients. The specificity of the mAb was further evaluated by immunoprecipitation techniques and by analysis of eluted fragments of C4 after immunoaffinity chromatography. The anti-C4c mAb was confirmed to be C4c specific, as it showed no cross-reactivity with native (un...

  7. Hydrogen isotopic differences between C3 and C4 land plant lipids: consequences of compartmentation in C4 photosynthetic chemistry and C3 photorespiration.

    Science.gov (United States)

    Zhou, Youping; Grice, Kliti; Stuart-Williams, Hilary; Hocart, Charles H; Gessler, Arthur; Farquhar, Graham D

    2016-12-01

    The 2 H/1 H ratio of carbon-bound H in biolipids holds potential for probing plant lipid biosynthesis and metabolism. The biochemical mechanism underlying the isotopic differences between lipids from C3 and C4 plants is still poorly understood. GC-pyrolysis-IRMS (gas chromatography-pyrolysis-isotope ratio mass spectrometry) measurement of the 2 H/1 H ratio of leaf lipids from controlled and field grown plants indicates that the biochemical isotopic fractionation (ε2 Hlipid_biochem ) differed between C3 and C4 plants in a pathway-dependent manner: ε2 HC4  > ε2 HC3 for the acetogenic pathway, ε2 HC4  C4 mesophyll (M) and bundle sheath (BS) cells and suppression of photorespiration in C4 M and BS cells both result in C4 M chloroplastic pyruvate - the precursor for acetogenic pathway - being more depleted in 2 H relative to pyruvate in C3 cells. In addition, compartmentation in C4 plants also results in (i) the transferable H of NADPH being enriched in 2 H in C4 M chloroplasts compared with that in C3 chloroplasts for the 1-deoxy-D-xylulose 5-phosphate pathway pathway and (ii) pyruvate relatively 2 H-enriched being used for the mevalonic acid pathway in the cytosol of BS cells in comparison with that in C3 cells. © 2016 John Wiley & Sons Ltd.

  8. Single-cell C(4) photosynthesis: efficiency and acclimation of Bienertia sinuspersici to growth under low light.

    Science.gov (United States)

    Stutz, Samantha S; Edwards, Gerald E; Cousins, Asaph B

    2014-04-01

    Traditionally, it was believed that C(4) photosynthesis required two types of chlorenchyma cells to concentrate CO(2) within the leaf. However, several species have been identified that perform C(4) photosynthesis using dimorphic chloroplasts within an individual cell. The goal of this research was to determine how growth under limited light affects leaf structure, biochemistry and efficiency of the single-cell CO(2) -concentrating mechanism in Bienertia sinuspersici. Measurements of rates of CO(2) assimilation and CO(2) isotope exchange in response to light intensity and O(2) were used to determine the efficiency of the CO(2) -concentrating mechanism in plants grown under moderate and low light. In addition, enzyme assays, chlorophyll content and light microscopy of leaves were used to characterize acclimation to light-limited growth conditions. There was acclimation to growth under low light with a decrease in capacity for photosynthesis when exposed to high light. This was associated with a decreased investment in biochemistry for carbon assimilation with only subtle changes in leaf structure and anatomy. The capture and assimilation of CO(2) delivered by the C(4) cycle was lower in low-light-grown plants. Low-light-grown plants were able to acclimate to maintain structural and functional features for the performance of efficient single-cell C(4) photosynthesis. © 2013 The Authors New Phytologist © 2013 New Phytologist Trust.

  9. Overexpression of a C4-dicarboxylate transporter is the key for rerouting citric acid to C4-dicarboxylic acid production in Aspergillus carbonarius.

    Science.gov (United States)

    Yang, Lei; Christakou, Eleni; Vang, Jesper; Lübeck, Mette; Lübeck, Peter Stephensen

    2017-03-14

    C4-dicarboxylic acids, including malic acid, fumaric acid and succinic acid, are valuable organic acids that can be produced and secreted by a number of microorganisms. Previous studies on organic acid production by Aspergillus carbonarius, which is capable of producing high amounts of citric acid from varieties carbon sources, have revealed its potential as a fungal cell factory. Earlier attempts to reroute citric acid production into C4-dicarboxylic acids have been with limited success. In this study, a glucose oxidase deficient strain of A. carbonarius was used as the parental strain to overexpress a native C4-dicarboxylate transporter and the gene frd encoding fumarate reductase from Trypanosoma brucei individually and in combination. Impacts of the introduced genetic modifications on organic acid production were investigated in a defined medium and in a hydrolysate of wheat straw containing high concentrations of glucose and xylose. In the defined medium, overexpression of the C4-dicarboxylate transporter alone and in combination with the frd gene significantly increased the production of C4-dicarboxylic acids and reduced the accumulation of citric acid, whereas expression of the frd gene alone did not result in any significant change of organic acid production profile. In the wheat straw hydrolysate after 9 days of cultivation, similar results were obtained as in the defined medium. High amounts of malic acid and succinic acid were produced by the same strains. This study demonstrates that the key to change the citric acid production into production of C4-dicarboxylic acids in A. carbonarius is the C4-dicarboxylate transporter. Furthermore it shows that the C4-dicarboxylic acid production by A. carbonarius can be further increased via metabolic engineering and also shows the potential of A. carbonarius to utilize lignocellulosic biomass as substrates for C4-dicarboxylic acid production.

  10. Expression of the peptide C4b‐binding protein β in the arthritic joint

    Science.gov (United States)

    Sánchez‐Pernaute, O; Esparza‐Gordillo, J; Largo, R; Calvo, E; Alvarez‐Soria, M A; Marcos, M E; Herrero‐Beaumont, G; de Córdoba, S R

    2006-01-01

    Background C4b‐binding protein (C4BP) is a plasma oligomeric glycoprotein that participates in the regulation of complement and haemostasis. Complement‐regulatory activity depends on the C4BPα‐polypeptide, whereas the C4BPβ‐polypeptide inactivates protein S, interfering with the anti‐coagulatory protein C‐dependent pathway. Objective To investigate the expression of C4BPβ in the rheumatoid joint. Methods Expression of C4BP was studied in synovial explants from patients with rheumatoid arthritis, osteoarthritis and healthy controls, using immunohistochemistry and in situ hybridisation. C4BP isoforms and free C4BPβ were studied in synovial effusions from patients with rheumatoid arthritis, osteoarthritis and microcrystalline arthritis (MCA) by immunoblotting; total and free protein S levels were studied by enzyme immunoassay. Results C4BPβ was overexpressed in the synovial membranes of patients with rheumatoid arthritis, in close association with the severity of synovitis and the extension of interstitial fibrin deposits. As many as 85% fluids from patients with rheumatoid arthritis contained free C4BPβ, whereas this unusual polypeptide was present in 50% fluids from patients with MCA and 40% fluids from patients with osteoarthritis. Free protein S at the effusions was pathologically reduced in patients with rheumatoid arthrits and MCA, and remained normal in patients with osteoarthritis. Conclusion C4BPβ is expressed by the inflamed synovial tissue, where it can participate in processes of tissue remodelling associated with invasive growth. PMID:16679431

  11. Analyzing the Light Energy Distribution in the Photosynthetic Apparatus of C4 Plants Using Highly Purified Mesophyll and Bundle-Sheath Thylakoids.

    Science.gov (United States)

    Pfundel, E.; Nagel, E.; Meister, A.

    1996-11-01

    The chlorophyll fluorescence characteristics of mesophyll and bundle-sheath thylakoids from plant species with the C4 dicarboxylic acid pathway of photosynthesis were investigated using flow cytometry. Ten species with the NADP-malic enzyme (NADP-ME) biochemical type of C4 photosynthesis were tested: Digitaria sanguinalis (L.) Scop., Euphorbia maculata L., Portulaca grandiflora Hooker, Saccharum officinarum L., Setaria viridis (L.) Beauv., Zea mays L., and four species of the genus Flaveria. This study also included three species with NAD-ME biochemistry (Atriplex rosea L., Atriplex spongiosa F. Muell., and Portulaca oleracea L.). Two C4 species of unknown biochemical type were investigated: Cyperus papyrus L. and Atriplex tatarica L. Pure mesophyll and bundle-sheath thylakoids were prepared by flow cytometry and characterized by low-temperature fluorescence spectroscopy. In pure bundle-sheath thylakoids from many species with C4 photosynthesis of the NADP-ME type, significant amounts of photosystem II (PSII) emission can be detected by fluorescence spectroscopy. Simulation of fluorescence excitation spectra of these thylakoids showed that PSII light absorption contributes significantly to the apparent excitation spectrum of photosystem I. Model calculations indicated that the excitation energy of PSII is efficiently transferred to photosystem I in bundle-sheath thylakoids of many NADP-ME species.

  12. The reinvestigation of the kinetics of the metathesis reactions t-C4H9• + HBr (HI) → i-C4H10 + Br• (I•) and of the t-C4H9• free radical thermochemistry.

    Science.gov (United States)

    Leplat, N; Rossi, M J

    2014-07-17

    A reinvestigation of the absolute rate constant of the metathesis reactions t-C4H9• + HBr → i-C4H10 + Br• (1) and t-C4H9• + HI → i-C4H10 + I• (2) was performed thanks to a recently developed apparatus consisting of a Knudsen reactor coupled to detection based on single-photon (VUV) photoionization mass spectrometry (SPIMS). It enables the generation of thermalized hydrocarbon free radicals owing to a source upstream of and external to the Knudsen reactor. The following Arrhenius expressions were obtained: k1 = 5.6(±1.4) × 10(–12) exp(−6.76(±0.94)/(RT)) and k2 = 2.0(±0.6) × 10(–11) exp(−8.48(±0.94)/(RT)) with R = 8.314 J mol(–1) K(–1) over the range 293 to 623 K. The mass balance of the reaction system based on closed shell product detection (CSPD) was checked in order to ensure the accuracy of the used reaction mechanism and as an independent check of k1 and k2. The wall-loss rate constants of the t-butyl free radical, kw(C4H9), were measured and found to be low compared with the corresponding escape rate constant, ke(C4H9), for effusion of t-C4H9• out of the Knudsen reactor. On the basis of the present results, the free radical standard heat of formation ΔfH298°(t-C4H9•) = 44.3 ± 1.7 kJ mol(–1) was obtained when combined with the kinetics of the inverse halogenation reaction taken from the literature and using S298°(t-C4H9•) = 322.2 J K(–1) mol(–1) following a “Third Law” evaluation method. The standard enthalpy for t-butyl free radical is consistent for both the bromination and iodination reactions within the stated uncertainties.

  13. The draft genome and transcriptome of Amaranthus hypochondriacus: a C4 dicot producing high-lysine edible pseudo-cereal.

    Science.gov (United States)

    Sunil, Meeta; Hariharan, Arun K; Nayak, Soumya; Gupta, Saurabh; Nambisan, Suran R; Gupta, Ravi P; Panda, Binay; Choudhary, Bibha; Srinivasan, Subhashini

    2014-12-01

    Grain amaranths, edible C4 dicots, produce pseudo-cereals high in lysine. Lysine being one of the most limiting essential amino acids in cereals and C4 photosynthesis being one of the most sought-after phenotypes in protein-rich legume crops, the genome of one of the grain amaranths is likely to play a critical role in crop research. We have sequenced the genome and transcriptome of Amaranthus hypochondriacus, a diploid (2n = 32) belonging to the order Caryophyllales with an estimated genome size of 466 Mb. Of the 411 linkage single-nucleotide polymorphisms (SNPs) reported for grain amaranths, 355 SNPs (86%) are represented in the scaffolds and 74% of the 8.6 billion bases of the sequenced transcriptome map to the genomic scaffolds. The genome of A. hypochondriacus, codes for at least 24,829 proteins, shares the paleohexaploidy event with species under the superorders Rosids and Asterids, harbours 1 SNP in 1,000 bases, and contains 13.76% of repeat elements. Annotation of all the genes in the lysine biosynthetic pathway using comparative genomics and expression analysis offers insights into the high-lysine phenotype. As the first grain species under Caryophyllales and the first C4 dicot genome reported, the work presented here will be beneficial in improving crops and in expanding our understanding of angiosperm evolution. © The Author 2014. Published by Oxford University Press on behalf of Kazusa DNA Research Institute.

  14. Systematic comparison of C3 and C4 plants based on metabolic network analysis.

    Science.gov (United States)

    Wang, Chuanli; Guo, Longyun; Li, Yixue; Wang, Zhuo

    2012-01-01

    The C4 photosynthetic cycle supercharges photosynthesis by concentrating CO2 around ribulose-1,5-bisphosphate carboxylase and significantly reduces the oxygenation reaction. Therefore engineering C4 feature into C3 plants has been suggested as a feasible way to increase photosynthesis and yield of C3 plants, such as rice, wheat, and potato. To identify the possible transition from C3 to C4 plants, the systematic comparison of C3 and C4 metabolism is necessary. We compared C3 and C4 metabolic networks using the improved constraint-based models for Arabidopsis and maize. By graph theory, we found the C3 network exhibit more dense topology structure than C4. The simulation of enzyme knockouts demonstrated that both C3 and C4 networks are very robust, especially when optimizing CO2 fixation. Moreover, C4 plant has better robustness no matter the objective function is biomass synthesis or CO2 fixation. In addition, all the essential reactions in C3 network are also essential for C4, while there are some other reactions specifically essential for C4, which validated that the basic metabolism of C4 plant is similar to C3, but C4 is more complex. We also identified more correlated reaction sets in C4, and demonstrated C4 plants have better modularity with complex mechanism coordinates the reactions and pathways than that of C3 plants. We also found the increase of both biomass production and CO2 fixation with light intensity and CO2 concentration in C4 is faster than that in C3, which reflected more efficient use of light and CO2 in C4 plant. Finally, we explored the contribution of different C4 subtypes to biomass production by setting specific constraints. All results are consistent with the actual situation, which indicate that Flux Balance Analysis is a powerful method to study plant metabolism at systems level. We demonstrated that in contrast to C3, C4 plants have less dense topology, higher robustness, better modularity, and higher CO2 and radiation use efficiency

  15. Evolutionary switch and genetic convergence on rbcL following the evolution of C4 photosynthesis.

    Science.gov (United States)

    Christin, Pascal-Antoine; Salamin, Nicolas; Muasya, A Muthama; Roalson, Eric H; Russier, Flavien; Besnard, Guillaume

    2008-11-01

    Rubisco is responsible for the fixation of CO2 into organic compounds through photosynthesis and thus has a great agronomic importance. It is well established that this enzyme suffers from a slow catalysis, and its low specificity results into photorespiration, which is considered as an energy waste for the plant. However, natural variations exist, and some Rubisco lineages, such as in C4 plants, exhibit higher catalytic efficiencies coupled to lower specificities. These C4 kinetics could have evolved as an adaptation to the higher CO2 concentration present in C4 photosynthetic cells. In this study, using phylogenetic analyses on a large data set of C3 and C4 monocots, we showed that the rbcL gene, which encodes the large subunit of Rubisco, evolved under positive selection in independent C4 lineages. This confirms that selective pressures on Rubisco have been switched in C4 plants by the high CO2 environment prevailing in their photosynthetic cells. Eight rbcL codons evolving under positive selection in C4 clades were involved in parallel changes among the 23 independent monocot C4 lineages included in this study. These amino acids are potentially responsible for the C4 kinetics, and their identification opens new roads for human-directed Rubisco engineering. The introgression of C4-like high-efficiency Rubisco would strongly enhance C3 crop yields in the future CO2-enriched atmosphere.

  16. An rbcL mRNA-binding protein is associated with C3 to C4 evolution and light-induced production of Rubisco in Flaveria.

    Science.gov (United States)

    Yerramsetty, Pradeep; Agar, Erin M; Yim, Won C; Cushman, John C; Berry, James O

    2017-07-20

    Nuclear-encoded RLSB protein binds chloroplastic rbcL mRNA encoding the Rubisco large subunit. RLSB is highly conserved across all groups of land plants and is associated with positive post-transcriptional regulation of rbcL expression. In C3 leaves, RLSB and Rubisco occur in all chlorenchyma cell chloroplasts, while in C4 leaves these accumulate only within bundle sheath (BS) chloroplasts. RLSB's role in rbcL expression makes modification of its localization a likely prerequisite for the evolutionary restriction of Rubisco to BS cells. Taking advantage of evolutionarily conserved RLSB orthologs in several C3, C3-C4, C4-like, and C4 photosynthetic types within the genus Flaveria, we show that low level RLSB sequence divergence and modification to BS specificity coincided with ontogeny of Rubisco specificity and Kranz anatomy during C3 to C4 evolution. In both C3 and C4 species, Rubisco production reflected RLSB production in all cell types, tissues, and conditions examined. Co-localization occurred only in photosynthetic tissues, and both proteins were co-ordinately induced by light at post-transcriptional levels. RLSB is currently the only mRNA-binding protein to be associated with rbcL gene regulation in any plant, with variations in sequence and acquisition of cell type specificity reflecting the progression of C4 evolution within the genus Flaveria. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  17. Common evolutionary origin of alpha 2-macroglobulin and complement components C3 and C4

    DEFF Research Database (Denmark)

    Sottrup-Jensen, Lars; Stepanik, T M; Kristensen, Torsten

    1985-01-01

    placed residues and account for 75% and 67%, respectively, of the polypeptide chains of alpha 2M and pro-C3. Published sequence data for complement component C4 show that segments of this protein match well with corresponding stretches in alpha 2M and pro-C3. It is proposed that alpha 2M, C3 and C4...... common gross structure. The quartets of basic residues in pro-C3 and pro-C4, at which cleavage takes place to produce the mature subunits of these proteins, and most of the residues forming the anaphylatoxin peptides of C3 and C4 (C3a and C4a) are absent in alpha 2M. In addition, C3 and C4 contain large...

  18. Fire ecology of C3 and C4 grasses depends on evolutionary history and frequency of burning but not photosynthetic type.

    Science.gov (United States)

    Ripley, Brad; Visser, Vernon; Christin, Pascal-Antoine; Archibald, Sally; Martin, Tarryn; Osborne, Colin

    2015-10-01

    Grasses using the C4 photosynthetic pathway dominate frequently burned savannas, where the pathway is hypothesized to be adaptive. However, independent C4 lineages also sort among different fire environments. Adaptations to fire may thus depend on evolutionary history, which could be as important as the possession of the C4 photosynthetic pathway for life in these environments. Here, using a comparative pot experiment and controlled burn, we examined C3 and C4 grasses belonging to four lineages from the same regional flora, and asked the following questions: Do lineages differ in their responses to fire, are responses consistent between photosynthetic types, and are responses related to fire frequency in natural habitats? We found that in the C4 Andropogoneae lineage, frost killed a large proportion of aboveground biomass and produced a large dry fuel load, which meant that only a small fraction of the living tissue was lost in the fire. C3 species from the Paniceae and Danthonioideae lineages generated smaller fuel loads and lost more living biomass, while species from the C4 lineage Aristida generated the smallest fuel loads and lost the most living tissue. Regrowth after the fire was more rapid and complete in the C4 Andropogoneae and C3 Paniceae, but incomplete and slower in the C3 Danthonioideae and C4 Aristida. Rapid recovery was associated with high photosynthetic rates, high specific leaf area, delayed flowering, and frequent fires in natural habitats. Results demonstrated that phylogenetic lineage was more important than photosynthetic type in determining the fire response of these grasses and that fire responses were related to the frequency that natural habitats burned.

  19. Involvement of C4 protein of beet severe curly top virus (family Geminiviridae in virus movement.

    Directory of Open Access Journals (Sweden)

    Kunling Teng

    Full Text Available BACKGROUND: Beet severe curly top virus (BSCTV is a leafhopper transmitted geminivirus with a monopartite genome. C4 proteins encoded by geminivirus play an important role in virus/plant interaction. METHODS AND FINDINGS: To understand the function of C4 encoded by BSCTV, two BSCTV mutants were constructed by introducing termination codons in ORF C4 without affecting the amino acids encoded by overlapping ORF Rep. BSCTV mutants containing disrupted ORF C4 retained the ability to replicate in Arabidopsis protoplasts and in the agro-inoculated leaf discs of N. benthamiana, suggesting C4 is not required for virus DNA replication. However, both mutants did not accumulate viral DNA in newly emerged leaves of inoculated N. benthamiana and Arabidopsis, and the inoculated plants were asymptomatic. We also showed that C4 expression in plant could help C4 deficient BSCTV mutants to move systemically. C4 was localized in the cytosol and the nucleus in both Arabidopsis protoplasts and N. benthamiana leaves and the protein appeared to bind viral DNA and ds/ssDNA nonspecifically, displaying novel DNA binding properties. CONCLUSIONS: Our results suggest that C4 protein in BSCTV is involved in symptom production and may facilitate virus movement instead of virus replication.

  20. Systematic Comparison of C3 and C4 Plants Based on Metabolic Network Analysis

    OpenAIRE

    Wang Chuanli; Guo Longyun; Li Yixue; Wang Zhuo

    2012-01-01

    Abstract Background The C4 photosynthetic cycle supercharges photosynthesis by concentrating CO2 around ribulose-1,5-bisphosphate carboxylase and significantly reduces the oxygenation reaction. Therefore engineering C4 feature into C3 plants has been suggested as a feasible way to increase photosynthesis and yield of C3 plants, such as rice, wheat, and potato. To identify the possible transition from C3 to C4 plants, the systematic comparison of C3 and C4 metabolism is necessary. Results We c...

  1. Plasma C4d+ Endothelial Microvesicles Increase in Acute Antibody-Mediated Rejection.

    Science.gov (United States)

    Tower, Cindy M; Reyes, Morayma; Nelson, Karen; Leca, Nicolae; Kieran, Niamh; Muczynski, Kimberly; Jefferson, Jonathan A; Blosser, Christopher; Kukla, Aleksandra; Maurer, David; Chandler, Wayne; Najafian, Behzad

    2017-09-01

    Antibody-mediated rejection (AMR) is a major cause of kidney allograft loss. Currently, AMR diagnosis relies on biopsy which is an invasive procedure. A noninvasive biomarker of acute AMR could lead to early diagnosis and treatment of this condition and improve allograft outcome. Microvesicles are membrane-bound vesicles released from the cell surface after injury. We hypothesized that because AMR is associated with allograft endothelial injury and C4d deposition, plasma microvesicles positive for endothelial (CD144) marker and C4d are increased in this condition. We studied microvesicle concentration in the plasma of 95 kidney transplant patients with allograft dysfunction and compared with 23 healthy volunteers. Biopsy diagnosis and scoring was performed using Banff classification. In the 28 subjects with AMR, the density of C4d+/CD144+ microvesicles was on average 11-fold (P = 0.002) higher than transplant recipients with no AMR and 24-fold (P = 0.008) than healthy volunteers. Densities of C4d+ and C4d+/annexin V+ (C4d+/AVB+) microvesicles were also increased in AMR patients compared with no AMR and healthy subjects. C4d+/AVB+ microvesicles correlated with AMR biopsy severity. Nine patients with acute AMR that received treatment showed a mean 72% decrease (P = 0.01) in C4d+/CD144+ microvesicle concentration compared with pretreatment values. Quantification of plasma C4d+ microvesicles provides information about presence of AMR, its severity and response to treatment in transplant patients.

  2. CSF/serum quotient graphs for the evaluation of intrathecal C4 synthesis

    Directory of Open Access Journals (Sweden)

    Rey Alexis

    2009-07-01

    Full Text Available Abstract Background Cerebrospinal fluid (CSF/serum quotient graphs have been used previously to determine local synthesis in brain of immunoglobulins and C3 complement component. The aim of this study was to use the same technique to construct quotient graphs, or Reibergrams, for the beta globulin C4 and to evaluate the method for assessing intrathecal synthesis in neurological disease. Methods The constants in the previously-defined Reibergram for immunoglobulin IgA were used to calculate the CSF/serum quotient for C4. CSF and serum were analyzed for C4, IgA and albumin from a total of 12 patients with meningoencephalitis caused by encapsulated microorganisms and 10 subjects without infections or inflammatory neurological disease, some of which had dysfunction of the blood-CSF barrier, Results The formula and C4 Reibergram with the constants previously found for IgA, determined the intrathecal C4 synthesis in CSF. The intrathecal C4 fraction in CSF (C4 loc in mg/l was compared to the C4-Index (fraction of CSF: serum for C 4/fraction of CSF: serum for albumin. There was a significant correlation between the two formulae. The CSF/Serum quotient graph was superior for detecting intrathecal synthesis of C4 under variable conditions of blood-CSF barrier permeability. Conclusion The C4 Reibergram can be used to quantify the intrathecal synthesis of this component of the complement system in different infectious diseases of the central nervous system and is especially useful for patients with blood-brain barrier dysfunction.

  3. Association of C4d Deposition with Clinical Outcomes in IgA Nephropathy

    Science.gov (United States)

    Ortega, Rosa; Sánchez, Marina; Segarra, Alfons; Salcedo, Maria Teresa; González, Fayna; Camacho, Rafael; Valdivia, Miguel Angel; Cabrera, Rocio; López, Katia; Pinedo, Fernando; Gutierrez, Eduardo; Valera, Alfonso; Leon, Miryam; Cobo, Maria Angeles; Rodriguez, Rosa; Ballarín, Jose; Arce, Yolanda; García, Beatriz; Muñoz, María Dolores; Praga, Manuel

    2014-01-01

    Background and objectives Several studies have suggested that activation of the complement system is a contributing pathogenic mechanism in IgA nephropathy (IgAN). C4d staining is an inexpensive and easy-to-perform method for the analysis of renal biopsies. This study aimed to assess the clinical and prognostic implications of C4d staining in IgAN. Design, setting, participants, & measurements This retrospective cohort study included 283 patients with IgAN in 11 hospitals in Spain who underwent a renal biopsy between 1979 and 2010. The primary predictor was mesangial C4d staining. Secondary predictors included demographic, clinical, and laboratory characteristics, and Oxford pathologic classification criteria. The primary end point was the cumulative percentage of patients who developed ESRD, defined as onset of chronic dialysis or renal transplantation. C4d was analyzed by immunohistochemical staining using a polyclonal antibody. Kaplan–Meier and Cox proportional hazards analyses were performed to evaluate the effect of C4d staining on renal survival. Results There were 109 patients (38.5%) and 174 patients (61.5%) who were classified as C4d positive and C4d negative, respectively. Renal survival at 20 years was 28% in C4d-positive patients versus 85% in C4d-negative patients (P50%; HR, 4.42; 95% CI, 1.40 to 13.88; P=0.01), and C4d-positive staining (HR, 2.45; 95% CI, 1.30 to 4.64; P=0.01). Conclusions C4d-positive staining is an independent risk factor for the development of ESRD in IgAN. This finding is consistent with the possibility that complement activation is involved in the pathogenesis of this disease. PMID:24578331

  4. Human pentraxin 3 binds to the complement regulator c4b-binding protein.

    Directory of Open Access Journals (Sweden)

    Anne Braunschweig

    Full Text Available The long pentraxin 3 (PTX3 is a soluble recognition molecule with multiple functions including innate immune defense against certain microbes and the clearance of apoptotic cells. PTX3 interacts with recognition molecules of the classical and lectin complement pathways and thus initiates complement activation. In addition, binding of PTX3 to the alternative complement pathway regulator factor H was shown. Here, we show that PTX3 binds to the classical and lectin pathway regulator C4b-binding protein (C4BP. A PTX3-binding site was identified within short consensus repeats 1-3 of the C4BP α-chain. PTX3 did not interfere with the cofactor activity of C4BP in the fluid phase and C4BP maintained its complement regulatory activity when bound to PTX3 on surfaces. While C4BP and factor H did not compete for PTX3 binding, the interaction of C4BP with PTX3 was inhibited by C1q and by L-ficolin. PTX3 bound to human fibroblast- and endothelial cell-derived extracellular matrices and recruited functionally active C4BP to these surfaces. Whereas PTX3 enhanced the activation of the classical/lectin pathway and caused enhanced C3 deposition on extracellular matrix, deposition of terminal pathway components and the generation of the inflammatory mediator C5a were not increased. Furthermore, PTX3 enhanced the binding of C4BP to late apoptotic cells, which resulted in an increased rate of inactivation of cell surface bound C4b and a reduction in the deposition of C5b-9. Thus, in addition to complement activators, PTX3 interacts with complement inhibitors including C4BP. This balanced interaction on extracellular matrix and on apoptotic cells may prevent excessive local complement activation that would otherwise lead to inflammation and host tissue damage.

  5. Volumetric Properties of the Mixture Butan-2-ol C4H10O + C4H10O 2-Methylpropan-2-ol (VMSD1211, LB4536_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Butan-2-ol C4H10O + C4H10O 2-Methylpropan-2-ol (VMSD1211, LB4536_V)' providing data from direct low-pressure dilatometric measurement of molar excess volume at variable mole fraction and constant temperature.

  6. Volumetric Properties of the Mixture N,N-Dimethylethanamide C4H9NO + C4H10O 2-Methylpropan-2-ol (VMSD1212, LB3723_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture N,N-Dimethylethanamide C4H9NO + C4H10O 2-Methylpropan-2-ol (VMSD1212, LB3723_V)' providing data by calculation of molar excess volume from low-pressure density measurements at variable mole fraction and constant temperature.

  7. Volumetric Properties of the Mixture Butanenitrile C4H7N + C4H10O 2-Methylpropan-2-ol (VMSD1111, LB4087_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Butanenitrile C4H7N + C4H10O 2-Methylpropan-2-ol (VMSD1111, LB4087_V)' providing data from direct low-pressure measurement of mass density at variable mole fraction and constant temperature, in the single-phase region(s).

  8. Volumetric Properties of the Mixture Butan-2-one C4H8O + C4H10O 2-Methylpropan-2-ol (VMSD1211, LB3990_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Butan-2-one C4H8O + C4H10O 2-Methylpropan-2-ol (VMSD1211, LB3990_V)' providing data from direct low-pressure dilatometric measurement of molar excess volume at variable mole fraction and constant temperature.

  9. Volumetric Properties of the Mixture 2-Methylpropan-1-ol C4H10O + C4H10O 2-Methylpropan-2-ol (VMSD1211, LB4537_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture 2-Methylpropan-1-ol C4H10O + C4H10O 2-Methylpropan-2-ol (VMSD1211, LB4537_V)' providing data from direct low-pressure dilatometric measurement of molar excess volume at variable mole fraction and constant temperature.

  10. Heat of Mixing and Solution of Butan-2-one C4H8O + C4H10O 2-Methylpropan-2-ol (HMSD1111, LB4043_H)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'heat of Mixing and Solution of Butan-2-one C4H8O + C4H10O 2-Methylpropan-2-ol (HMSD1111, LB4043_H)' providing data from direct low-pressure calorimetric measurement of molar excess enthalpy at variable mole fraction and constant temperature.

  11. Heat of Mixing and Solution of 2-Methylpropan-2-ol C4H10O + C4H11N tert-Butylamine (HMSD1111, LB4104_H)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'heat of Mixing and Solution of 2-Methylpropan-2-ol C4H10O + C4H11N tert-Butylamine (HMSD1111, LB4104_H)' providing data from direct low-pressure calorimetric measurement of molar excess enthalpy at variable mole fraction and constant temperature.

  12. Volumetric Properties of the Mixture Butanenitrile C4H7N + C4H10O 2-Methylpropan-2-ol (VMSD1212, LB4090_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Butanenitrile C4H7N + C4H10O 2-Methylpropan-2-ol (VMSD1212, LB4090_V)' providing data by calculation of molar excess volume from low-pressure density measurements at variable mole fraction and constant temperature.

  13. Volumetric Properties of the Mixture Butan-1-ol C4H10O + C4H10O 2-Methylpropan-2-ol (VMSD1211, LB4535_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Butan-1-ol C4H10O + C4H10O 2-Methylpropan-2-ol (VMSD1211, LB4535_V)' providing data from direct low-pressure dilatometric measurement of molar excess volume at variable mole fraction and constant temperature.

  14. Volumetric Properties of the Mixture 2-Methylpropan-2-ol C4H10O + C4H11N tert-Butylamine (VMSD1211, LB4187_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture 2-Methylpropan-2-ol C4H10O + C4H11N tert-Butylamine (VMSD1211, LB4187_V)' providing data from direct low-pressure dilatometric measurement of molar excess volume at variable mole fraction and constant temperature.

  15. Volumetric Properties of the Mixture N,N-Dimethylethanamide C4H9NO + C4H10O 2-Methylpropan-2-ol (VMSD1111, LB3726_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture N,N-Dimethylethanamide C4H9NO + C4H10O 2-Methylpropan-2-ol (VMSD1111, LB3726_V)' providing data from direct low-pressure measurement of mass density at variable mole fraction and constant temperature, in the single-phase region(s).

  16. Increased complement C4d deposition at the maternal-fetal interface in unexplained recurrent miscarriage

    NARCIS (Netherlands)

    Meuleman, Tess; Cohen, Danielle; Swings, Godelieve M J S; Veraar, Kimberly; Claas, Frans H J; Bloemenkamp, Kitty W M

    2015-01-01

    C4d is a footprint of antibody-mediated classical complement activation, and has evolved as a useful diagnostic marker of antibody-mediated rejection. It is unknown if complement activation, as reflected by C4d deposition plays a role in unexplained recurrent miscarriage. In a case-control study

  17. Data of evolutionary structure change: 1AHPA-2C4MD [Confc[Archive

    Lifescience Database Archive (English)

    Full Text Available 1AHPA-2C4MD 1AHP 2C4M A D SQPIFNDKQFQEALSRQWQRYGLNSAAEMTPRQWWLAVSEALAEMLRAQ--PFAKP...1AHP A 1AHPA MLRAQ--PFAKP...1AHP A 1AHPA SLQKE-WANDL ...1AHP A 1AHPA LHSIG----KQGGD...1AHP A 1AHPA DVLYR-DQEAW

  18. Data of evolutionary structure change: 1AHPA-2C4MA [Confc[Archive

    Lifescience Database Archive (English)

    Full Text Available 1AHPA-2C4MA 1AHP 2C4M A A SQPIFNDKQFQEALSRQWQRYGLNSAAEMTPRQWWLAVSEALAEM-----------...1AHP A 1AHPA SLQKE-WANDL ...1AHP A 1AHPA LHSIG----KQGGD...1AHP A 1AHPA DVLYR-DQEAW ...1AHP A 1AHPA RQWQRYGLNSAAEM

  19. Data of evolutionary structure change: 1AHPA-2C4MB [Confc[Archive

    Lifescience Database Archive (English)

    Full Text Available 1AHPA-2C4MB 1AHP 2C4M A B SQPIFNDKQFQEALSRQWQRYGLNSAAEMTPRQWWLAVSEALAEMLRAQPFAKPV-...1AHP A 1AHPA FAKPV--ANQRH...1AHP A 1AHPA SLQKE-WANDL ...1AHP A 1AHPA LHSIG----KQGGD...1AHP A 1AHPA DVLYR-DQEAW

  20. Integration of C4-specific ppdk gene of Echinochloa to C3 upland ...

    African Journals Online (AJOL)

    Pyruvate orthophosphate dikinase (PPDK) plays a key role in C4 photosynthetic pathway. The enzymatic reaction is one of the rate-limiting steps of the C4 photosynthetic pathway. In this paper, the gene encoding Echinochloa pyruvate orthosphate dikinase (GenBank accession number: AB289641) was introduced into H65 ...

  1. Data of evolutionary structure change: 1C4ZD-2ESPA [Confc[Archive

    Lifescience Database Archive (English)

    Full Text Available 1C4ZD-2ESPA 1C4Z 2ESP D A ---SRRLMKELEEIRKCGMKNFRNIQVDEANLLTWQGLI...Y-- AMALKRIHKELNDLARDPPAQCSAGPVGD-DMFHWQATIMGPNDSPYQGGVFFLTIHFPTDYPFKPPKVAFTTRIYHPNINSNGSICLDALR-SQWSPA...tryChain> 2ESP A 2ESPA 2ESP A 2ESPA 2 2ESP A 2ESPA

  2. MOLECULAR HETEROGENEITY OF THE 4TH COMPONENT OF COMPLEMENT (C4) AND ITS GENES IN VITILIGO

    NARCIS (Netherlands)

    VENNEKER, GT; WESTERHOF, W; DEVRIES, IJ; DRAYER, NM; WOLTHERS, BG; DEWAAL, LP; BOS, JD; ASGHAR, SS

    1992-01-01

    In view of evidence suggesting vitiligo is an autoimmune disease, we investigated whether vitiligo is associated with inherited deficiencies of the fourth (C4) and second (C2) component of complement and with certain human leukocyte antigens (HLA). Analysis of functional activities of C4 and C2 in

  3. Engineering C4 photosynthesis into C3 chassis in the synthetic biology age.

    Science.gov (United States)

    Schuler, Mara L; Mantegazza, Otho; Weber, Andreas P M

    2016-07-01

    C4 photosynthetic plants outperform C3 plants in hot and arid climates. By concentrating carbon dioxide around Rubisco C4 plants drastically reduce photorespiration. The frequency with which plants evolved C4 photosynthesis independently challenges researchers to unravel the genetic mechanisms underlying this convergent evolutionary switch. The conversion of C3 crops, such as rice, towards C4 photosynthesis is a long-standing goal. Nevertheless, at the present time, in the age of synthetic biology, this still remains a monumental task, partially because the C4 carbon-concentrating biochemical cycle spans two cell types and thus requires specialized anatomy. Here we review the advances in understanding the molecular basis and the evolution of the C4 trait, advances in the last decades that were driven by systems biology methods. In this review we emphasise essential genetic engineering tools needed to translate our theoretical knowledge into engineering approaches. With our current molecular understanding of the biochemical C4 pathway, we propose a simplified rational engineering model exclusively built with known C4 metabolic components. Moreover, we discuss an alternative approach to the progressing international engineering attempts that would combine targeted mutagenesis and directed evolution. © 2016 The Authors The Plant Journal © 2016 John Wiley & Sons Ltd.

  4. 26 CFR 1.381(c)(4)-1 - Method of accounting.

    Science.gov (United States)

    2010-04-01

    ... 26 Internal Revenue 4 2010-04-01 2010-04-01 false Method of accounting. 1.381(c)(4)-1 Section 1... TAX (CONTINUED) INCOME TAXES Insolvency Reorganizations § 1.381(c)(4)-1 Method of accounting. (a... section 381(a) applies, an acquiring corporation shall use the same method of accounting used by the...

  5. Phosphoenolpyruvate carboxylase from C4 leaves is selectively targeted for inhibition by anionic phospholipids

    NARCIS (Netherlands)

    Monreal, J.A.; McLoughlin, F.; Echevarría, C.; García-Mauriño, S.; Testerink, C.

    2010-01-01

    Phosphoenolpyruvate carboxylase (PEPC; EC 4.1.1.31) is an enzyme playing a crucial role in photosynthesis of C4 plants. Here, we identify anionic phospholipids as novel regulators that inhibit C4 PEPC activity and provide evidence that the enzyme partially localizes to membranes.

  6. Platelet - activating factor induces leukotriene C4 synthesis by purified human eosinophils

    NARCIS (Netherlands)

    Bruijnzeel, P.L.B.; Kok, P.T.M.; Hamelink, M.L.; Kijne, A.M.; Verhagen, J.

    Platelet-activating factor, at a concentration of 10 μM, was capable of inducing leukotriene C4 synthesis by eosinophils of healthy donors, i.e. (3.1 ± 0.3) × 106 molecules leukotriene C4 /cell (n = 31, mean ± SEM, cell purity 87 ± 2%). Reversed-phase high performance liquid chromatography analysis

  7. Mesophyll conductance in Zea mays responds transiently to CO2availability: implications for transpiration efficiency in C4crops.

    Science.gov (United States)

    Kolbe, Allison R; Cousins, Asaph B

    2018-03-01

    Mesophyll conductance (g m ) describes the movement of CO 2 from the intercellular air spaces below the stomata to the site of initial carboxylation in the mesophyll. In contrast with C 3 -g m , little is currently known about the intraspecific variation in C 4 -g m or its responsiveness to environmental stimuli. To address these questions, g m was measured on five maize (Zea mays) lines in response to CO 2 , employing three different estimates of g m . Each of the methods indicated a significant response of g m to CO 2 . Estimates of g m were similar between methods at ambient and higher CO 2 , but diverged significantly at low partial pressures of CO 2 . These differences are probably driven by incomplete chemical and isotopic equilibrium between CO 2 and bicarbonate under these conditions. Carbonic anhydrase and phosphoenolpyruvate carboxylase in vitro activity varied significantly despite similar values of g m and leaf anatomical traits. These results provide strong support for a CO 2 response of g m in Z. mays, and indicate that g m in maize is probably driven by anatomical constraints rather than by biochemical limitations. The CO 2 response of g m indicates a potential role for facilitated diffusion in C 4 -g m . These results also suggest that water-use efficiency could be enhanced in C 4 species by targeting g m . © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  8. Variations of Leaf Cuticular Waxes Among C3 and C4 Gramineae Herbs.

    Science.gov (United States)

    He, Yuji; Gao, Jianhua; Guo, Na; Guo, Yanjun

    2016-11-01

    Modern C4 plants are commonly distributed in hot and dry environments whereas C3 plants predominate in cool and shade areas. At the outmost of plant surface, the deposition and chemical composition of cuticular waxes vary under different environmental conditions. However, whether such variation of cuticular wax is related to the distribution of C3 and C4 under different environmental conditions is still not clear. In this study, leaves of six C3 Gramineae herbs distributed in spring, Roegneria kamoji, Polypogon fugax, Poa annua, Avena fatua, Alopecurus aequalis, and Oplismenus undulatifolius, and four C4 and one C3 Gramineae herbs distributed in summer, Digitaria sanguinalis, Eleusine indica, Setaria viridis, S. plicata, and O. undulatifolius, were sampled and analyzed for cuticular wax. Plates were the main epicuticular wax morphology in both C3 and C4 plants except S. plicata. The plates melted in C4 plants but not in C3 plants. The total cuticular wax amounts in C4 plants were significantly lower than those in C3 plants, except for O. undulatifolius. Primary alcohols were the most abundant compounds in C3 plants, whereas n-alkanes were relatively the most abundant compounds in C4 plants. C29 was the most abundant n-alkane in C3 plants except for O. undulatifolius, whereas the most abundant n-alkane was C31 or C33 in C4 plants. The average chain length (ACL) of n-alkanes was higher in C4 than in C3 plants, whereas the ACL of n-alkanoic acids was higher in C3 than C4 plants. The cluster analysis based on the distribution of n-alkanes clearly distinguished C3 and C4 plants into two groups, except for O. undulatifolius which was grouped with C4 plants. These results suggest that the variations of cuticular waxes among C3 and C4 Gramineae herbs are related to the distribution of C3 and C4 plants under different environmental conditions. © 2016 Wiley-VHCA AG, Zurich, Switzerland.

  9. Structural analysis and tissue localization of human C4.4A

    DEFF Research Database (Denmark)

    Hansen, Line V.; Gårdsvoll, Henrik; Nielsen, Boye S

    2004-01-01

    C4.4A, a structural homologue of the urokinase-type plasminogen activator receptor (uPAR), was originally identified as a metastasis-associated membrane protein, but little is known about its structural and functional properties. Therefore, we expressed, purified and characterized a soluble...... significant amounts of GPI-anchored C4.4A, we find no evidence for an interaction between C4.4A and uPA, a property suggested previously for rat C4.4A. Collectively these data indicate that C4.4A, although being a structural homologue of uPAR, is unlikely to have a functional overlap with uPAR....

  10. C13C4.5/Spinster, an evolutionarily conserved protein that regulates fertility in C. elegans through a lysosome-mediated lipid metabolism process.

    Science.gov (United States)

    Han, Mei; Chang, Hao; Zhang, Peng; Chen, Tao; Zhao, Yanhua; Zhang, Yongdeng; Liu, Pingsheng; Xu, Tao; Xu, Pingyong

    2013-05-01

    Lipid droplets, which are conserved across almost all species, are cytoplasmic organelles used to store neutral lipids. Identification of lipid droplet regulators will be conducive to resolving obesity and other fat-associated diseases. In this paper, we selected 11 candidates that might be associated with lipid metabolism in Caenorhabditis elegans. Using a BODIPY 493/503-based flow cytometry screen, 6 negative and 3 positive regulators of fat content were identified. We selected one negative regulator of lipid content, C13C4.5, for future study. C13C4.5 was mainly expressed in the worm intestine. We found that this gene was important for maintaining the metabolism of lipid droplets. Biochemical results revealed that 50% of triacylglycerol (TAG) was lost in C13C4.5 knockout worms. Stimulated Raman scattering (SRS) signals in C13C4.5 mutants showed only 49.6% of the fat content in the proximal intestinal region and 86.3% in the distal intestinal region compared with wild type animals. The mean values of lipid droplet size and intensity in C13C4.5 knockout animals were found to be significantly decreased compared with those in wild type worms. The LMP-1-labeled membrane structures in worm intestines were also enlarged in C13C4.5 mutant animals. Finally, fertility defects were found in C13C4.5(ok2087) mutants. Taken together, these results indicate that C13C4.5 may regulate the fertility of C. elegans by changing the size and fat content of lipid droplets by interfering with lysosomal morphology and function.

  11. C4 photosynthesis in C3 rice: a theoretical analysis of biochemical and anatomical factors.

    Science.gov (United States)

    Wang, Shuyue; Tholen, Danny; Zhu, Xin-Guang

    2017-01-01

    Engineering C4 photosynthesis into rice has been considered a promising strategy to increase photosynthesis and yield. A question that remains to be answered is whether expressing a C4 metabolic cycle into a C3 leaf structure and without removing the C3 background metabolism improves photosynthetic efficiency. To explore this question, we developed a 3D reaction diffusion model of bundle-sheath and connected mesophyll cells in a C3 rice leaf. Our results show that integrating a C4 metabolic pathway into rice leaves with a C3 metabolism and mesophyll structure may lead to an improved photosynthesis under current ambient CO2 concentration. We analysed a number of physiological factors that influence the CO2 uptake rate, which include the chloroplast surface area exposed to intercellular air space, bundle-sheath cell wall thickness, bundle-sheath chloroplast envelope permeability, Rubisco concentration and the energy partitioning between C3 and C4 cycles. Among these, partitioning of energy between C3 and C4 photosynthesis and the partitioning of Rubisco between mesophyll and bundle-sheath cells are decisive factors controlling photosynthetic efficiency in an engineered C3 -C4 leaf. The implications of the results for the sequence of C4 evolution are also discussed. © 2016 John Wiley & Sons Ltd.

  12. Chalcone-based Selective Inhibitors of a C4 Plant Key Enzyme as Novel Potential Herbicides

    Science.gov (United States)

    Nguyen, G. T. T.; Erlenkamp, G.; Jäck, O.; Küberl, A.; Bott, M.; Fiorani, F.; Gohlke, H.; Groth, G.

    2016-06-01

    Weeds are a challenge for global food production due to their rapidly evolving resistance against herbicides. We have identified chalcones as selective inhibitors of phosphoenolpyruvate carboxylase (PEPC), a key enzyme for carbon fixation and biomass increase in the C4 photosynthetic pathway of many of the world’s most damaging weeds. In contrast, many of the most important crop plants use C3 photosynthesis. Here, we show that 2‧,3‧,4‧,3,4-Pentahydroxychalcone (IC50 = 600 nM) and 2‧,3‧,4‧-Trihydroxychalcone (IC50 = 4.2 μM) are potent inhibitors of C4 PEPC but do not affect C3 PEPC at a same concentration range (selectivity factor: 15-45). Binding and modeling studies indicate that the active compounds bind at the same site as malate/aspartate, the natural feedback inhibitors of the C4 pathway. At the whole plant level, both substances showed pronounced growth-inhibitory effects on the C4 weed Amaranthus retroflexus, while there were no measurable effects on oilseed rape, a C3 plant. Growth of selected soil bacteria was not affected by these substances. Our chalcone compounds are the most potent and selective C4 PEPC inhibitors known to date. They offer a novel approach to combat C4 weeds based on a hitherto unexplored mode of allosteric inhibition of a C4 plant key enzyme.

  13. High-biomass C4 grasses-Filling the yield gap.

    Science.gov (United States)

    Mullet, John E

    2017-08-01

    A significant increase in agricultural productivity will be required by 2050 to meet the needs of an expanding and rapidly developing world population, without allocating more land and water resources to agriculture, and despite slowing rates of grain yield improvement. This review examines the proposition that high-biomass C4 grasses could help fill the yield gap. High-biomass C4 grasses exhibit high yield due to C4 photosynthesis, long growth duration, and efficient capture and utilization of light, water, and nutrients. These C4 grasses exhibit high levels of drought tolerance during their long vegetative growth phase ideal for crops grown in water-limited regions of agricultural production. The stems of some high-biomass C4 grasses can accumulate high levels of non-structural carbohydrates that could be engineered to enhance biomass yield and utility as feedstocks for animals and biofuels production. The regulatory pathway that delays flowering of high-biomass C4 grasses in long days has been elucidated enabling production and deployment of hybrids. Crop and landscape-scale modeling predict that utilization of high-biomass C4 grass crops on land and in regions where water resources limit grain crop yield could increase agricultural productivity. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Temperature response of photosynthesis in C3, C4, and CAM plants: temperature acclimation and temperature adaptation.

    Science.gov (United States)

    Yamori, Wataru; Hikosaka, Kouki; Way, Danielle A

    2014-02-01

    Most plants show considerable capacity to adjust their photosynthetic characteristics to their growth temperatures (temperature acclimation). The most typical case is a shift in the optimum temperature for photosynthesis, which can maximize the photosynthetic rate at the growth temperature. These plastic adjustments can allow plants to photosynthesize more efficiently at their new growth temperatures. In this review article, we summarize the basic differences in photosynthetic reactions in C3, C4, and CAM plants. We review the current understanding of the temperature responses of C3, C4, and CAM photosynthesis, and then discuss the underlying physiological and biochemical mechanisms for temperature acclimation of photosynthesis in each photosynthetic type. Finally, we use the published data to evaluate the extent of photosynthetic temperature acclimation in higher plants, and analyze which plant groups (i.e., photosynthetic types and functional types) have a greater inherent ability for photosynthetic acclimation to temperature than others, since there have been reported interspecific variations in this ability. We found that the inherent ability for temperature acclimation of photosynthesis was different: (1) among C3, C4, and CAM species; and (2) among functional types within C3 plants. C3 plants generally had a greater ability for temperature acclimation of photosynthesis across a broad temperature range, CAM plants acclimated day and night photosynthetic process differentially to temperature, and C4 plants was adapted to warm environments. Moreover, within C3 species, evergreen woody plants and perennial herbaceous plants showed greater temperature homeostasis of photosynthesis (i.e., the photosynthetic rate at high-growth temperature divided by that at low-growth temperature was close to 1.0) than deciduous woody plants and annual herbaceous plants, indicating that photosynthetic acclimation would be particularly important in perennial, long-lived species that

  15. Renal AA amyloidosis in a patient with hereditary complete complement C4 deficiency

    Directory of Open Access Journals (Sweden)

    Imed Helal

    2011-01-01

    Full Text Available Hereditary complete C4 deficiency has until now been reported in 30 cases only. A disturbed clearance of immune- complexes probably predisposes these individuals to systemic lupus erythematosus, other immune- complex diseases and recurrent microbial infections. We present here a 20- year- old female with hereditary complete C4 deficiency. Renal biopsy demonstrated renal AA amyloidosis. This unique case further substantiates that deficiency of classical pathway components predisposes to the development of recurrent microbial infections and that the patients may develop AA amyloidosis. Furthermore, in clinical practice, the nephrotic syndrome occurring in a patient with hereditary complete complement C4 deficiency should lead to the suspicion of renal AA amyloidosis.

  16. Inhibition of complement components C3 and C4 by cadralazine and its active metabolite.

    Science.gov (United States)

    Andersson, M; Hanson, A; Englund, G; Dahlbäck, B

    1991-01-01

    The effect of cadralazine and its active metabolite CGP 22639 on the covalent binding reaction of C4 and C3 has been studied. Trypsin-Sepharose was used to activate radio-labelled C3 and C4 and binding of the radio-labelled protein to the trypsin-Sepharose was measured. Cadralazine inhibited 50% of the binding of C3 and C4 at concentrations of 19 mmol/l and 15 mmol/l, respectively. Its active metabolite was more potent and inhibited 50% of the C3 and C4 binding at concentrations of 8 and 3.5 mmol/l, respectively. These concentrations are much higher than those found in plasma during therapy. This is consistent with the clinical observation that in patients with normal kidney function cadralazine is not an inducer of SLE.

  17. Chemical bonding in electron-deficient boron oxide clusters: core boronyl groups, dual 3c-4e hypervalent bonds, and rhombic 4c-4e bonds.

    Science.gov (United States)

    Chen, Qiang; Lu, Haigang; Zhai, Hua-Jin; Li, Si-Dian

    2014-04-28

    We explore the structural and bonding properties of the electron-deficient boron oxide clusters, using a series of B3On(-/0/+) (n = 2-4) clusters as examples. Global-minimum structures of these boron oxide clusters are identified via unbiased Coalescence Kick and Basin Hopping searches, which show a remarkable size and charge-state dependence. An array of new bonding elements are revealed: core boronyl groups, dual 3c-4e hypervalent bonds (ω-bonds), and rhombic 4c-4e bonds (o-bonds). In favorable cases, oxygen can exhaust all its 2s/2p electrons to facilitate the formation of B-O bonds. The current findings should help understand the bonding nature of low-dimensional boron oxide nanomaterials and bulk boron oxides.

  18. C4 expansion in the central Inner Mongolia during the latest Miocene and early Pliocene

    Science.gov (United States)

    Zhang, Chunfu; Wang, Yang; Deng, Tao; Wang, Xiaoming; Biasatti, Dana; Xu, Yingfeng; Li, Qiang

    2009-10-01

    The emergence of C4 photosynthesis in plants as a significant component of terrestrial ecosystems is thought to be an adaptive response to changes in atmospheric CO 2 concentration and/or climate during Neogene times and has had a profound effect on the global terrestrial biosphere. Although expansion of C4 grasses in the latest Miocene and Pliocene has been widely documented around the world, the spatial and temporal variations in the C4 expansion are still not well understood and its driving mechanisms remain a contentious issue. Here we present the results of carbon and oxygen isotope analyses of fossil and modern mammalian tooth enamel samples from the central Inner Mongolia. Our samples represent a diverse group of herbivorous mammals including deer, elephants, rhinos, horses and giraffes, ranging in age from the late Oligocene to modern. The δ13C values of 91 tooth enamel samples of early late-Miocene age or older, with the exception of two 13 Ma rhino samples (- 7.8 and - 7.6‰) and one 8.5 Ma suspected rhino sample (- 7.6‰), were all less than - 8.0‰ (VPDB), indicating that there were no C4 grasses present in their diets and thus probably few or no C4 grasses in the ecosystems of the central Inner Mongolia prior to ~ 8 Ma. However, 12 out of 26 tooth enamel samples of younger ages (~ 7.5 Ma to ~ 3.9 Ma) have δ13C values higher than - 8.0‰ (up to - 2.4‰), indicating that herbivores in the area had variable diets ranging from pure C3 to mixed C3-C4 vegetation during that time interval. The presence of C4 grasses in herbivores' diets (up to ~ 76% C4) suggests that C4 grasses were a significant component of the local ecosystems in the latest Miocene and early Pliocene, consistent with the hypothesis of a global factor as the driving mechanism of the late Miocene C4 expansion. Today, C3 grasses dominate grasslands in the central Inner Mongolia area. The retreat of C4 grasses from this area after the early Pliocene may have been driven by regional

  19. Metabolic Network Constrains Gene Regulation of C4 Photosynthesis: The Case of Maize

    OpenAIRE

    Robaina-Est?vez, Semid?n; Nikoloski, Zoran

    2016-01-01

    Engineering C3 plants to increase their efficiency of carbon fixation as well as of nitrogen and water use simultaneously may be facilitated by understanding the mechanisms that underpin the C4 syndrome. Existing experimental studies have indicated that the emergence of the C4 syndrome requires co-ordination between several levels of cellular organization, from gene regulation to metabolism, across two co-operating cell systems?mesophyll and bundle sheath cells. Yet, determining the extent to...

  20. NDH-Mediated Cyclic Electron Flow Around Photosystem I is Crucial for C4 Photosynthesis.

    Science.gov (United States)

    Ishikawa, Noriko; Takabayashi, Atsushi; Noguchi, Ko; Tazoe, Youshi; Yamamoto, Hiroshi; von Caemmerer, Susanne; Sato, Fumihiko; Endo, Tsuyoshi

    2016-10-01

    C4 photosynthesis exhibits efficient CO2 assimilation in ambient air by concentrating CO2 around ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) through a metabolic pathway called the C4 cycle. It has been suggested that cyclic electron flow (CEF) around PSI mediated by chloroplast NADH dehydrogenase-like complex (NDH), an alternative pathway of photosynthetic electron transport (PET), plays a crucial role in C4 photosynthesis, although the contribution of NDH-mediated CEF is small in C3 photosynthesis. Here, we generated NDH-suppressed transformants of a C4 plant, Flaveria bidentis, and showed that the NDH-suppressed plants grow poorly, especially under low-light conditions. CO2 assimilation rates were consistently decreased in the NDH-suppressed plants under low and medium light intensities. Measurements of non-photochemical quenching (NPQ) of Chl fluorescence, the oxidation state of the reaction center of PSI (P700) and the electrochromic shift (ECS) of pigment absorbance indicated that proton translocation across the thylakoid membrane is impaired in the NDH-suppressed plants. Since proton translocation across the thylakoid membrane induces ATP production, these results suggest that NDH-mediated CEF plays a role in the supply of ATP which is required for C4 photosynthesis. Such a role is more crucial when the light that is available for photosynthesis is limited and the energy production by PET becomes rate-determining for C4 photosynthesis. Our results demonstrate that the physiological contribution of NDH-mediated CEF is greater in C4 photosynthesis than in C3 photosynthesis, suggesting that the mechanism of PET in C4 photosynthesis has changed from that in C3 photosynthesis accompanying the changes in the mechanism of CO2 assimilation. © The Author 2016. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  1. Klasifikasi Penerimaan Mahasiswa Baru Menggunakan Algortima C4.5 Dan Adaboost (Studi Kasus : STMIK XYZ

    Directory of Open Access Journals (Sweden)

    Yoga Handoko Agustin

    2017-02-01

    Full Text Available Every college student wants to get a good quality and the quantity corresponding to the quota in charge of the university. The quality of new students can be seen early by recognizing the pattern of student characteristics existing in previous years and noticed a long period of study.C4.5 algorithm is a model for building a decision tree, this algorithm is intended for supervised learning: value attribute in the dataset described by a collection of attributes and including one of a series of interconnected classes. To improve the accuracy in the process of classification and prediction by means generate a combination of a model, then used modeling boosting namely Adaboost. Experiments conducted on 546 datasets using C4.5 algorithms based adaboost to produce accuracy. From the experiments conducted to produce the same accuracy values between algorithm C4.5 and C4.5 algorithm based on Adaboost is equal to 77.33% Precision, Accuracy 90.28%, 45.54% Recall but there is a difference in AUC values for C4.5 Algorithm by 0683 while Adaboost algorithm C4.5 Driven by 0.717. The patterns can help to take the decision of new admissions to graduate on time and graduate students can be predictable late early.

  2. Genome-scale modeling of the evolutionary path to C4 photosynthesis

    Science.gov (United States)

    Myers, Christopher R.; Bogart, Eli

    In C4 photosynthesis, plants maintain a high carbon dioxide level in specialized bundle sheath cells surrounding leaf veins and restrict CO2 assimilation to those cells, favoring CO2 over O2 in competition for Rubisco active sites. In C3 plants, which do not possess such a carbon concentrating mechanism, CO2 fixation is reduced due to this competition. Despite the complexity of the C4 system, it has evolved convergently from more than 60 independent origins in diverse families of plants around the world over the last 30 million years. We study the evolution of the C4 system in a genome-scale model of plant metabolism that describes interacting mesophyll and bundle sheath cells and enforces key nonlinear kinetic relationships. Adapting the zero-temperature string method for simulating transition paths in physics and chemistry, we find the highest-fitness paths connecting C3 and C4 positions in the model's high-dimensional parameter space, and show that they reproduce known aspects of the C3-C4 transition while making additional predictions about metabolic changes along the path. We explore the relationship between evolutionary history and C4 biochemical subtype, and the effects of atmospheric carbon dioxide levels.

  3. Rising atmospheric carbon dioxide concentration and the future of C4 crops for food and fuel.

    Science.gov (United States)

    Leakey, Andrew D B

    2009-07-07

    Crops with the C(4) photosynthetic pathway are vital to global food supply, particularly in the tropical regions where human well-being and agricultural productivity are most closely linked. While rising atmospheric [CO(2)] is the driving force behind the greater temperatures and water stress, which threaten to reduce future crop yields, it also has the potential to directly benefit crop physiology. The nature of C(4) plant responses to elevated [CO(2)] has been controversial. Recent evidence from free-air CO(2) enrichment (FACE) experiments suggests that elevated [CO(2)] does not directly stimulate C(4) photosynthesis. Nonetheless, drought stress can be ameliorated at elevated [CO(2)] as a result of lower stomatal conductance and greater intercellular [CO(2)]. Therefore, unlike C(3) crops for which there is a direct enhancement of photosynthesis by elevated [CO(2)], C(4) crops will only benefit from elevated [CO(2)] in times and places of drought stress. Current projections of future crop yields have assumed that rising [CO(2)] will directly enhance photosynthesis in all situations and, therefore, are likely to be overly optimistic. Additional experiments are needed to evaluate the extent to which amelioration of drought stress by elevated [CO(2)] will improve C(4) crop yields for food and fuel over the range of C(4) crop growing conditions and genotypes.

  4. Seasonal discrimination of C3 and C4 grasses functional types: An evaluation of the prospects of varying spectral configurations of new generation sensors

    Science.gov (United States)

    Shoko, Cletah; Mutanga, Onisimo

    2017-10-01

    The present study assessed the potential of varying spectral configuration of Landsat 8 Operational Land Imager (OLI), Sentinel 2 MultiSpectal Instrument (MSI) and Worldview 2 sensors in the seasonal discrimination of Festuca costata (C3) and Themeda Triandra (C4) grass species in the Drakensberg, South Africa. This was achieved by resampling hyperspectral measurements to the spectral windows corresponding to the three sensors at two distinct seasonal periods (summer peak and end of winter), using the Discriminant Analysis (DA) classification ensemble. In summer, standard bands of the Worldview 2 produced the highest overall classification accuracy (98.61%), followed by Sentinel 2 (97.52%), whereas the Landsat 8 spectral configuration was the least performer, using vegetation indices (95.83%). In winter, Sentinel 2 spectral bands produced the highest accuracy (96.18%) for the two species, followed by Worldview 2 (94.44%) and Landsat 8 yielded the least (91.67%) accuracy. Results also showed that maximum separability between C3 and C4 grasses was in summer, while at the end of winter considerable overlaps were noted, especially when using the spectral settings of the Landsat 8 OLI and Sentinel 2 shortwave infrared bands. Test of significance in species reflectance further confirmed that in summer, there were significant differences (P 0.05) between the two species. In this regard, the peak summer period presents a promising opportunity for the spectral discrimination of C3 and C4 grass species functional types, than the end of winter, when using multispectral sensors. Results from this study highlight the influence of seasonality on discrimination and therefore provide the basis for the successful discrimination and mapping of C3 and C4 grass species.

  5. Structural and biochemical characterization of the C3–C4 intermediate Brassica gravinae and relatives, with particular reference to cellular distribution of Rubisco

    Science.gov (United States)

    Ueno, Osamu

    2011-01-01

    On the basis of its CO2 compensation concentration, Brassica gravinae Ten. has been reported to be a C3–C4 intermediate. This study investigated the structural and biochemical features of photosynthetic metabolism in B. gravinae. The cellular distribution of ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) was also examined in B. gravinae, B. napus L. (C3), Raphanus sativus L. (C3), and Diplotaxis tenuifolia (L.) DC. (C3–C4) by immunogold electron microscopy to elucidate Rubisco expression during the evolution from C3 to C3–C4 intermediate plants. The bundle sheath (BS) cells of B. gravinae contained centrifugally located chloroplasts as well as centripetally located chloroplasts and mitochondria. Glycine decarboxylase P-protein was localized in the BS mitochondria. Brassica gravinae had low C4 enzyme activities and high activities of Rubisco and photorespiratory enzymes, suggesting that it reduces photorespiratory CO2 loss by the glycine shuttle. In B. gravinae, the labelling density of Rubisco was higher in the mesophyll chloroplasts than in the BS chloroplasts. A similar cellular pattern was found in other Brassicaceae species. These data demonstrate that, during the evolution from C3 to C3–C4 intermediate plants, the intercellular pattern of Rubisco expression did not change greatly, although the amount of chloroplasts in the BS cells increased. It also appears that intracellular variation in Rubisco distribution may occur within the BS cells of B. gravinae. PMID:21825284

  6. The acclimation of photosynthesis and respiration to temperature in the C3 -C4 intermediate Salsola divaricata: induction of high respiratory CO2 release under low temperature.

    Science.gov (United States)

    Gandin, Anthony; Koteyeva, Nuria K; Voznesenskaya, Elena V; Edwards, Gerald E; Cousins, Asaph B

    2014-11-01

    Photosynthesis in C(3) -C(4) intermediates reduces carbon loss by photorespiration through refixing photorespired CO(2) within bundle sheath cells. This is beneficial under warm temperatures where rates of photorespiration are high; however, it is unknown how photosynthesis in C(3) -C(4) plants acclimates to growth under cold conditions. Therefore, the cold tolerance of the C(3) -C(4) Salsola divaricata was tested to determine whether it reverts to C(3) photosynthesis when grown under low temperatures. Plants were grown under cold (15/10 °C), moderate (25/18 °C) or hot (35/25 °C) day/night temperatures and analysed to determine how photosynthesis, respiration and C(3) -C(4) features acclimate to these growth conditions. The CO(2) compensation point and net rates of CO(2) assimilation in cold-grown plants changed dramatically when measured in response to temperature. However, this was not due to the loss of C(3) -C(4) intermediacy, but rather to a large increase in mitochondrial respiration supported primarily by the non-phosphorylating alternative oxidative pathway (AOP) and, to a lesser degree, the cytochrome oxidative pathway (COP). The increase in respiration and AOP capacity in cold-grown plants likely protects against reactive oxygen species (ROS) in mitochondria and photodamage in chloroplasts by consuming excess reductant via the alternative mitochondrial respiratory electron transport chain. © 2014 John Wiley & Sons Ltd.

  7. Plasma C4d as marker for lupus nephritis in systemic lupus erythematosus.

    Science.gov (United States)

    Martin, Myriam; Smoląg, Karolina I; Björk, Albin; Gullstrand, Birgitta; Okrój, Marcin; Leffler, Jonatan; Jönsen, Andreas; Bengtsson, Anders A; Blom, Anna M

    2017-12-06

    In the present study, we sought to evaluate the complement activation product C4d as a marker for lupus nephritis in systemic lupus erythematosus (SLE). C4d levels were determined by enzyme-linked immunosorbent assay in plasma samples of patients with established SLE using a novel approach based on detection of a short linear cleavage neoepitope. Cross-sectional associations were studied in 98 patients with SLE with samples taken at lower or higher respective disease activity. Temporal associations were investigated in 69 patients with SLE who were followed longitudinally for up to 5 years. Plasma samples from 77 healthy donors were included as controls. C4d levels were negligible in healthy control subjects and significantly increased in patients with SLE in the cross-sectional study (p Lupus Erythematosus Disease Activity Index (p = 0.011) and predominantly with lupus nephritis (p = 0.003), exhibiting a sensitivity of 79% to identify patients with nephritis. High C4d levels together with the presence of anti-dsDNA autoantibodies preceded and thus predicted future lupus nephritis in the longitudinal study (OR 5.4, 95% CI 1.4-21.3). When we considered only patients with renal involvement (19 of 69) during the longitudinal study, we found that high C4d levels alone could forecast recurrence of future lupus nephritis (OR 3.3, 95% CI 1.2-9.6). C4d appears to be a valuable marker for use in monitoring of patients with SLE, particularly for lupus nephritis. Importantly, C4d levels can predict impending flares of lupus nephritis and may thus be useful for informing treatment.

  8. C4/5 foraminal stenosis predicts C5 palsy after expansive open-door laminoplasty.

    Science.gov (United States)

    Lee, Ho-Jin; Ahn, Jae-Sung; Shin, Byungkon; Lee, Hoseok

    2017-04-21

    Laminoplasty is frequently performed in cervical myelopathy patients, but can lead to unexpected postoperative C5 palsy. Although several studies have examined the pathogenesis and prevention of postoperative C5 palsy, many controversies remain and some radiological findings identified as risk factors were not correlated with our outcomes. This study sought reliable radiological findings that predict C5 palsy after laminoplasty and examined why the predictors of C5 palsy did not apply in our series. This study reviewed 116 patients who underwent open-door laminoplasty for cervical spondylotic myelopathy between January 2014 and April 2016, retrospectively. C5 palsy was defined as weakness of the deltoid muscle. We evaluated the incidence of C5 palsy, the preoperative C2-7 Cobb's angle, and Pavlov ratio at the C4/C5 level using simple cervical lateral radiographs. We also evaluated the existence of an ossified posterior longitudinal ligament, the transverse diameter of the C4/5 foramen, and increases in the anteroposterior diameter of the spinal canal at the C4/5 levels after surgery. Furthermore, a high signal intensity on T2-weighted images of the cervical spinal cord preoperatively was noted. Of the 116 patients, 16 cases were excluded and 100 cases were analyzed; postoperative C5 palsy occurred in 8 patients (8%). There were no significant differences between the two groups except the average diameter of the C4/5 foramen. A diameter of the C4/5 foramen of less than 2 mm was significantly related to C5 palsy in the binary logistic regression test. A smaller diameter of the C4/5 foramen was the only factor significantly correlated with C5 palsy after laminoplasty. The results suggest that C4/5 foraminal stenosis is one of the best predictors of C5 palsy, which might be related to ischemic/reperfusion injury of the C5 root nerve after laminoplasty.

  9. Growth of the C4 dicot Flaveria bidentis: photosynthetic acclimation to low light through shifts in leaf anatomy and biochemistry.

    Science.gov (United States)

    Pengelly, Jasper J L; Sirault, Xavier R R; Tazoe, Youshi; Evans, John R; Furbank, Robert T; von Caemmerer, Susanne

    2010-09-01

    In C(4) plants, acclimation to growth at low irradiance by means of anatomical and biochemical changes to leaf tissue is considered to be limited by the need for a close interaction and coordination between bundle sheath and mesophyll cells. Here differences in relative growth rate (RGR), gas exchange, carbon isotope discrimination, photosynthetic enzyme activity, and leaf anatomy in the C(4) dicot Flaveria bidentis grown at a low (LI; 150 micromol quanta m(2) s(-1)) and medium (MI; 500 micromol quanta m(2) s(-1)) irradiance and with a 12 h photoperiod over 36 d were examined. RGRs measured using a 3D non-destructive imaging technique were consistently higher in MI plants. Rates of CO(2) assimilation per leaf area measured at 1500 micromol quanta m(2) s(-1) were higher for MI than LI plants but did not differ on a mass basis. LI plants had lower Rubisco and phosphoenolpyruvate carboxylase activities and chlorophyll content on a leaf area basis. Bundle sheath leakiness of CO(2) (phi) calculated from real-time carbon isotope discrimination was similar for MI and LI plants at high irradiance. phi increased at lower irradiances, but more so in MI plants, reflecting acclimation to low growth irradiance. Leaf thickness and vein density were greater in MI plants, and mesophyll surface area exposed to intercellular airspace (S(m)) and bundle sheath surface area per unit leaf area (S(b)) measured from leaf cross-sections were also both significantly greater in MI compared with LI leaves. Both mesophyll and bundle sheath conductance to CO(2) diffusion were greater in MI compared with LI plants. Despite being a C(4) species, F. bidentis is very plastic with respect to growth irradiance.

  10. Reduced combustion mechanism for C1-C4 hydrocarbons and its application in computational fluid dynamics flare modeling.

    Science.gov (United States)

    Damodara, Vijaya; Chen, Daniel H; Lou, Helen H; Rasel, Kader M A; Richmond, Peyton; Wang, Anan; Li, Xianchang

    2017-05-01

    Emissions from flares constitute unburned hydrocarbons, carbon monoxide (CO), soot, and other partially burned and altered hydrocarbons along with carbon dioxide (CO2) and water. Soot or visible smoke is of particular concern for flare operators/regulatory agencies. The goal of the study is to develop a computational fluid dynamics (CFD) model capable of predicting flare combustion efficiency (CE) and soot emission. Since detailed combustion mechanisms are too complicated for (CFD) application, a 50-species reduced mechanism, LU 3.0.1, was developed. LU 3.0.1 is capable of handling C4 hydrocarbons and soot precursor species (C2H2, C2H4, C6H6). The new reduced mechanism LU 3.0.1 was first validated against experimental performance indicators: laminar flame speed, adiabatic flame temperature, and ignition delay. Further, CFD simulations using LU 3.0.1 were run to predict soot emission and CE of air-assisted flare tests conducted in 2010 in Tulsa, Oklahoma, using ANSYS Fluent software. Results of non-premixed probability density function (PDF) model and eddy dissipation concept (EDC) model are discussed. It is also noteworthy that when used in conjunction with the EDC turbulence-chemistry model, LU 3.0.1 can reasonably predict volatile organic compound (VOC) emissions as well. A reduced combustion mechanism containing 50 C1-C4 species and soot precursors has been developed and validated against experimental data. The combustion mechanism is then employed in the computational fluid dynamics (CFD) of modeling of soot emission and combustion efficiency (CE) of controlled flares for which experimental soot and CE data are available. The validated CFD modeling tools are useful for oil, gas, and chemical industries to comply with U.S. Environmental Protection Agency's (EPA) mandate to achieve smokeless flaring with a high CE.

  11. Mitochondrial haplogroup C4c: a rare lineage entering America through the ice-free corridor?

    Science.gov (United States)

    Hooshiar Kashani, Baharak; Perego, Ugo A; Olivieri, Anna; Angerhofer, Norman; Gandini, Francesca; Carossa, Valeria; Lancioni, Hovirag; Semino, Ornella; Woodward, Scott R; Achilli, Alessandro; Torroni, Antonio

    2012-01-01

    Recent analyses of mitochondrial genomes from Native Americans have brought the overall number of recognized maternal founding lineages from just four to a current count of 15. However, because of their relative low frequency, almost nothing is known for some of these lineages. This leaves a considerable void in understanding the events that led to the colonization of the Americas following the Last Glacial Maximum (LGM). In this study, we identified and completely sequenced 14 mitochondrial DNAs belonging to one extremely rare Native American lineage known as haplogroup C4c. Its age and geographical distribution raise the possibility that C4c marked the Paleo-Indian group(s) that entered North America from Beringia through the ice-free corridor between the Laurentide and Cordilleran ice sheets. The similarities in ages andgeographical distributions for C4c and the previously analyzed X2a lineage provide support to the scenario of a dual origin for Paleo-Indians. Taking into account that C4c is deeply rooted in the Asian portion of the mtDNA phylogeny and is indubitably of Asian origin, the finding that C4c and X2a are characterized by parallel genetic histories definitively dismisses the controversial hypothesis of an Atlantic glacial entry route into North America. Copyright © 2011 Wiley Periodicals, Inc.

  12. Metabolic Network Constrains Gene Regulation of C4 Photosynthesis: The Case of Maize.

    Science.gov (United States)

    Robaina-Estévez, Semidán; Nikoloski, Zoran

    2016-05-01

    Engineering C3 plants to increase their efficiency of carbon fixation as well as of nitrogen and water use simultaneously may be facilitated by understanding the mechanisms that underpin the C4 syndrome. Existing experimental studies have indicated that the emergence of the C4 syndrome requires co-ordination between several levels of cellular organization, from gene regulation to metabolism, across two co-operating cell systems-mesophyll and bundle sheath cells. Yet, determining the extent to which the structure of the C4 plant metabolic network may constrain gene expression remains unclear, although it will provide an important consideration in engineering C4 photosynthesis in C3 plants. Here, we utilize flux coupling analysis with the second-generation maize metabolic models to investigate the correspondence between metabolic network structure and transcriptomic phenotypes along the maize leaf gradient. The examined scenarios with publically available data from independent experiments indicate that the transcriptomic programs of the two cell types are co-ordinated, quantitatively and qualitatively, due to the presence of coupled metabolic reactions in specific metabolic pathways. Taken together, our study demonstrates that precise quantitative coupling will have to be achieved in order to ensure a successfully engineered transition from C3 to C4 crops. © The Author 2016. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists.

  13. Nature's green revolution: the remarkable evolutionary rise of C4 plants.

    Science.gov (United States)

    Osborne, Colin P; Beerling, David J

    2006-01-29

    Plants with the C4 photosynthetic pathway dominate today's tropical savannahs and grasslands, and account for some 30% of global terrestrial carbon fixation. Their success stems from a physiological CO2-concentrating pump, which leads to high photosynthetic efficiency in warm climates and low atmospheric CO2 concentrations. Remarkably, their dominance of tropical environments was achieved in only the past 10 million years (Myr), less than 3% of the time that terrestrial plants have existed on Earth. We critically review the proposal that declining atmospheric CO2 triggered this tropical revolution via its effects on the photosynthetic efficiency of leaves. Our synthesis of the latest geological evidence from South Asia and North America suggests that this emphasis is misplaced. Instead, we find important roles for regional climate change and fire in South Asia, but no obvious environmental trigger for C4 success in North America. CO2-starvation is implicated in the origins of C4 plants 25-32 Myr ago, raising the possibility that the pathway evolved under more extreme atmospheric conditions experienced 10 times earlier. However, our geochemical analyses provide no evidence of the C4 mechanism at this time, although possible ancestral components of the C4 pathway are identified in ancient plant lineages. We suggest that future research must redress the substantial imbalance between experimental investigations and analyses of the geological record.

  14. Sistem Pakar Identifikasi Modalitas Belajar Siswa Dengan Implementasi Algoritma C4.5

    Directory of Open Access Journals (Sweden)

    Rachmawati Soewono

    2016-01-01

    Full Text Available C4.5 Algorithm is one of the classification technique in machine learning which is used in data mining process by build a decision tree which is represent in the rules. The aims of classification technique in data mining is to recognize the regularity of the pattern and the relation in a huge dataset by historical data collection. Students’ modalities measurement which is done by the questionnaire is produce historical data which is potentially to be processed to generate the classification that can be converted in rules. The expert acquisition and the C4.5 algorithm classification rules are used as knowledge base in the expert system. Therefore this research is done to build an expert system of the student’s modalities identification by implementing C4.5 algorithm that can produce seven categories of modalities classification, they are : visual, auditory, kinesthetic, visual-auditory, visual-kinesthetic, auditory-kinesthetic and visual-auditory-kinesthetic which has good in accuracy. The accuracy of the C4.5 algorithm classification and the expert system testing prediction is 80%. Keywords : Expert system; Decision tree; C4.5 Algorithm; Modalities.  

  15. Combining genetic and evolutionary engineering to establish C4 metabolism in C3 plants.

    Science.gov (United States)

    Li, Yuanyuan; Heckmann, David; Lercher, Martin J; Maurino, Veronica G

    2017-01-01

    To feed a world population projected to reach 9 billion people by 2050, the productivity of major crops must be increased by at least 50%. One potential route to boost the productivity of cereals is to equip them genetically with the 'supercharged' C4 type of photosynthesis; however, the necessary genetic modifications are not sufficiently understood for the corresponding genetic engineering programme. In this opinion paper, we discuss a strategy to solve this problem by developing a new paradigm for plant breeding. We propose combining the bioengineering of well-understood traits with subsequent evolutionary engineering, i.e. mutagenesis and artificial selection. An existing mathematical model of C3-C4 evolution is used to choose the most promising path towards this goal. Based on biomathematical simulations, we engineer Arabidopsis thaliana plants that express the central carbon-fixing enzyme Rubisco only in bundle sheath cells (Ru-BSC plants), the localization characteristic for C4 plants. This modification will initially be deleterious, forcing the Ru-BSC plants into a fitness valley from where previously inaccessible adaptive steps towards C4 photosynthesis become accessible through fitness-enhancing mutations. Mutagenized Ru-BSC plants are then screened for improved photosynthesis, and are expected to respond to imposed artificial selection pressures by evolving towards C4 anatomy and biochemistry. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  16. Identification of C4 photosynthesis metabolism and regulatory-associated genes in Eleocharis vivipara by SSH.

    Science.gov (United States)

    Chen, Taiyu; Ye, Rongjian; Fan, Xiaolei; Li, Xianghua; Lin, Yongjun

    2011-09-01

    This is the first effort to investigate the candidate genes involved in kranz developmental regulation and C(4) metabolic fluxes in Eleocharis vivipara, which is a leafless freshwater amphibious plant and possesses a distinct culms anatomy structure and photosynthetic pattern in contrasting environments. A terrestrial specific SSH library was constructed to investigate the genes involved in kranz anatomy developmental regulation and C(4) metabolic fluxes. A total of 73 ESTs and 56 unigenes in 384 clones were identified by array hybridization and sequencing. In total, 50 unigenes had homologous genes in the databases of rice and Arabidopsis. The real-time quantitative PCR results showed that most of the genes were accumulated in terrestrial culms and ABA-induced culms. The C(4) marker genes were stably accumulated during the culms development process in terrestrial culms. With respect to C(3) culms, C(4) photosynthesis metabolism consumed much more transporters and translocators related to ion metabolism, organic acids and carbohydrate metabolism, phosphate metabolism, amino acids metabolism, and lipids metabolism. Additionally, ten regulatory genes including five transcription factors, four receptor-like proteins, and one BURP protein were identified. These regulatory genes, which co-accumulated with the culms developmental stages, may play important roles in culms structure developmental regulation, bundle sheath chloroplast maturation, and environmental response. These results shed new light on the C(4) metabolic fluxes, environmental response, and anatomy structure developmental regulation in E. vivipara.

  17. Record of C4 Photosynthesis Through the Late Neogene and Pleistocene

    Science.gov (United States)

    Cerling, T. E.

    2016-12-01

    C4 photosynthesis is an adaptation to the low atmospheric carbon dioxide concentrations experienced in the Neogene; it is found principally in tropical to sub-tropical/temperate regions where temperatures are high in the growing season. Although C4 photosynthesis makes up about 50% of Net Primary Productivity in tropical regions, its macroscopic fossil record is extremely sparse. Therefore, inferences to its significance in local ecosystems are based primarily on stable isotopes, with phytoliths become more important as phytolith morphology becomes better associated with plant structure and classification. Stable isotopes have been the principal recorder for understanding the history of C4 photosynthesis; however, different materials record different aspects of the C4 contribution to ecosystem structure and thus are telling different parts of the same story. With the fossil record so poorly known, we often assume similar ecosystem structures and functions as we observe in modern analogues. It is likely that large evolutionary changes have taken place within C4 plants as they went from 50% tropical NPP in the late Neogene.

  18. Plasticity of metabolic networks and the evolution of C4 photosynthesis

    Science.gov (United States)

    Bogart, Eli; Myers, Chris

    2012-02-01

    Over 50 groups of plants have independently developed a common mechanism (C4 photosynthesis) for increasing the efficiency of photosynthetic carbon dioxide assimilation. Understanding the high degree of evolvability of the C4 system could offer useful guidance for attempts to introduce it artificially to other plants. Previously, the nonlinear relationship between carbon dioxide levels and rates of carbon assimilation and photorespiration has prevented the application of genome-scale metabolic models to the problem of the evolution of the pathway. We apply a nonlinear optimization method to find feasible flux distributions in a plant metabolic model, allowing us to explore the plasticity of the metabolic network and characterize the fitness landscape of the transition from C3 to C4 photosynthesis.

  19. Al4SiC4 wurtzite crystal: Structural, optoelectronic, elastic, and piezoelectric properties

    Directory of Open Access Journals (Sweden)

    L. Pedesseau

    2015-12-01

    Full Text Available New experimental results supported by theoretical analyses are proposed for aluminum silicon carbide (Al4SiC4. A state of the art implementation of the density functional theory is used to analyze the experimental crystal structure, the Born charges, the elastic properties, and the piezoelectric properties. The Born charge tensor is correlated to the local bonding environment for each atom. The electronic band structure is computed including self-consistent many-body corrections. Al4SiC4 material properties are compared to other wide band gap wurtzite materials. From a comparison between an ellipsometry study of the optical properties and theoretical results, we conclude that the Al4SiC4 material has indirect and direct band gap energies of about 2.5 eV and 3.2 eV, respectively.

  20. The urokinase receptor and its structural homologue C4.4A in human cancer

    DEFF Research Database (Denmark)

    Jacobsen, B; Ploug, M

    2008-01-01

    in the human genome. The structural relationship between the two proteins is, however, not reflected at the functional level. Whereas uPAR has a well-established role in regulating and focalizing uPA-mediated plasminogen activation to the surface of those cells expressing the receptor, the biological function...... of C4.4A remains elusive. Nonetheless, both uPAR and C4.4A have been implicated in human pathologies such as wound healing and cancer. A large body of experimental evidence thus demonstrates that high levels of uPAR in resected tumour tissue as well as in plasma are associated with poor prognosis......The urokinase-type plasminogen activator receptor (uPAR) and its structural homologue C4.4A are multidomain members of the Ly6/uPAR/alpha-neurotoxin protein domain family. Both are glycosylphosphatidylinositol-anchored membrane glycoproteins encoded by neighbouring genes located on chromosome 19q13...

  1. HYDRATION MECHANISMS OF CALCIUM SULPHOALUMINATE C4A3S̄ , C4AS̄ PHASE AND ACTIVE BELITE β-C2S

    Directory of Open Access Journals (Sweden)

    H. EL-DIDAMONY

    2012-12-01

    Full Text Available Highly reactive belite and calcium sulphoaluminate as well as monosulphate mix were prepared from nano-materials at lower temperatures ~1250°C. The crystal size of these materials was 25, 16 and 27 nm as determined from the X-ray analysis. The sulphoaluminate belite cement is a recent type of cement prepared at lower temperature with good properties. The aim of the present work is to synthesize C4A3S̄, monosulphate mix C4AS̄ and active belite β-C2S. The hydration mechanism was studied by XRD and DSC techniques as well as by the determination of chemically combined water contents of cement pastes with curing time. The results reveal that ettringite is first formed hydrates in the monosulphate mix, which then converted into monosulphate hydrates. The results of DSC and XRD are in good agreement with those of combined water contents. On the other side, the rate of hydration of active belite increases linearly from 3 up to 90 days, whereas, the traditional belite hydrates increase with lower rate up to 90 days, due to the thermodynamic stability structure of traditional belite.

  2. Intracellular position of mitochondria in mesophyll cells differs between C3and C4grasses.

    Science.gov (United States)

    Hatakeyama, Yuto; Ueno, Osamu

    2017-09-01

    In C 3 plants, part of the CO 2 fixed during photosynthesis in chloroplasts is released from mitochondria during photorespiration by decarboxylation of glycine via glycine decarboxylase (GDC), thereby reducing photosynthetic efficiency. The apparent positioning of most mitochondria in the interior (vacuole side of chloroplasts) of mesophyll cells in C 3 grasses would increase the efficiency of refixation of CO 2 released from mitochondria by ribulose 1,5-bisphosphate carboxylase/​oxygenase (Rubisco) in chloroplasts. Therefore, in mesophyll cells of C 4 grasses, which lack both GDC and Rubisco, the mitochondria ought not to be positioned the same way as in C 3 mesophyll cells. To test this hypothesis, we investigated the intracellular position of mitochondria in mesophyll cells of 14 C 4 grasses of different C 4 subtypes and subfamilies (Chloridoideae, Micrairoideae, and Panicoideae) and a C 3 -C 4 intermediate grass, Steinchisma hians, under an electron microscope. In C 4 mesophyll cells, most mitochondria were positioned adjacent to the cell wall, which clearly differs from the positioning in C 3 mesophyll cells. In S. hians mesophyll cells, the positioning was similar to that in C 3 cells. These results suggest that the mitochondrial positioning in C 4 mesophyll cells reflects the absence of both GDC and Rubisco in the mesophyll cells and the high activity of phosphoenolpyruvate carboxylase. In contrast, the relationship between the mitochondrial positioning and enzyme distribution in S. hians is complex, but the positioning may be related to the capture of respiratory CO 2 by Rubisco. Our study provides new possible insight into the physiological role of mitochondrial positioning in photosynthetic cells.

  3. Significant accumulation of C(4)-specific pyruvate, orthophosphate dikinase in a C(3) plant, rice.

    Science.gov (United States)

    Fukayama, H; Tsuchida, H; Agarie, S; Nomura, M; Onodera, H; Ono, K; Lee, B H; Hirose, S; Toki, S; Ku, M S; Makino, A; Matsuoka, M; Miyao, M

    2001-11-01

    The C(4)-Pdk gene encoding the C(4) enzyme pyruvate, orthophosphate dikinase (PPDK) of maize (Zea mays cv Golden Cross Bantam) was introduced into the C(3) plant, rice (Oryza sativa cv Kitaake). When the intact maize C(4)-Pdk gene, containing its own promoter and terminator sequences and exon/intron structure, was introduced, the PPDK activity in the leaves of some transgenic lines was greatly increased, in one line reaching 40-fold over that of wild-type plants. In a homozygous line, the PPDK protein accounted for 35% of total leaf-soluble protein or 16% of total leaf nitrogen. In contrast, introduction of a chimeric gene containing the full-length cDNA of the maize PPDK fused to the maize C(4)-Pdk promoter or the rice Cab promoter only increased PPDK activity and protein level slightly. These observations suggest that the intron(s) or the terminator sequence of the maize gene, or a combination of both, is necessary for high-level expression. In maize and transgenic rice plants carrying the intact maize gene, the level of transcript in the leaves per copy of the maize C(4)-Pdk gene was comparable, and the maize gene was expressed in a similar organ-specific manner. These results suggest that the maize C(4)-Pdk gene behaves in a quantitatively and qualitatively similar way in maize and transgenic rice plants. The activity of the maize PPDK protein expressed in rice leaves was light/dark regulated as it is in maize. This is the first reported evidence for the presence of an endogenous PPDK regulatory protein in a C(3) plant.

  4. A novel RNA binding protein affects rbcL gene expression and is specific to bundle sheath chloroplasts in C4 plants.

    Science.gov (United States)

    Bowman, Shaun M; Patel, Minesh; Yerramsetty, Pradeep; Mure, Christopher M; Zielinski, Amy M; Bruenn, Jeremy A; Berry, James O

    2013-09-22

    Plants that utilize the highly efficient C4 pathway of photosynthesis typically possess kranz-type leaf anatomy that consists of two morphologically and functionally distinct photosynthetic cell types, the bundle sheath (BS) and mesophyll (M) cells. These two cell types differentially express many genes that are required for C4 capability and function. In mature C4 leaves, the plastidic rbcL gene, encoding the large subunit of the primary CO2 fixation enzyme Rubisco, is expressed specifically within BS cells. Numerous studies have demonstrated that BS-specific rbcL gene expression is regulated predominantly at post-transcriptional levels, through the control of translation and mRNA stability. The identification of regulatory factors associated with C4 patterns of rbcL gene expression has been an elusive goal for many years. RLSB, encoded by the nuclear RLSB gene, is an S1-domain RNA binding protein purified from C4 chloroplasts based on its specific binding to plastid-encoded rbcL mRNA in vitro. Co-localized with LSU to chloroplasts, RLSB is highly conserved across many plant species. Most significantly, RLSB localizes specifically to leaf bundle sheath (BS) cells in C4 plants. Comparative analysis using maize (C4) and Arabidopsis (C3) reveals its tight association with rbcL gene expression in both plants. Reduced RLSB expression (through insertion mutation or RNA silencing, respectively) led to reductions in rbcL mRNA accumulation and LSU production. Additional developmental effects, such as virescent/yellow leaves, were likely associated with decreased photosynthetic function and disruption of associated signaling networks. Reductions in RLSB expression, due to insertion mutation or gene silencing, are strictly correlated with reductions in rbcL gene expression in both maize and Arabidopsis. In both plants, accumulation of rbcL mRNA as well as synthesis of LSU protein were affected. These findings suggest that specific accumulation and binding of the RLSB binding

  5. Dynamic and quasi-static measurements of C-4 and primasheet P1000 explosives

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Geoffrey W [Los Alamos National Laboratory; Thompson, Darla G [Los Alamos National Laboratory; De Luca, Racci [Los Alamos National Laboratory; Rae, Philip J [Los Alamos National Laboratory; Cady, Carl M [Los Alamos National Laboratory; Todd, Steven N [SNL

    2010-01-01

    We have measured dynamic and quasi-static mechanical properties of C-4 and Primasheet P1000 explosive materials to provide input data for modeling efforts. Primasheet P1000 is a pentaerythritol tetranitrate-based rubberized explosive. C-4 is a RDX-based moldable explosive. Dynamic measurements included acoustic and split-Hopkinson pressure bar tests. Quasi-static testing was done in compression on load frames and on a dynamic mechanical analyzer. Split-Hopkinson and quasi-static tests were done at five temperatures from -50 C to 50 C. Acoustic velocities were measured at, above, and below room temperature.

  6. The C4 clustering algorithm: Clusters of galaxies in the Sloan Digital Sky Survey

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Christopher J.; Nichol, Robert; Reichart, Dan; Wechsler, Risa H.; Evrard, August; Annis, James; McKay, Timothy; Bahcall, Neta; Bernardi, Mariangela; Boehringer,; Connolly, Andrew; Goto, Tomo; Kniazev, Alexie; Lamb, Donald; Postman, Marc; Schneider, Donald; Sheth, Ravi; Voges, Wolfgang; /Cerro-Tololo InterAmerican Obs. /Portsmouth U.,

    2005-03-01

    We present the ''C4 Cluster Catalog'', a new sample of 748 clusters of galaxies identified in the spectroscopic sample of the Second Data Release (DR2) of the Sloan Digital Sky Survey (SDSS). The C4 cluster-finding algorithm identifies clusters as overdensities in a seven-dimensional position and color space, thus minimizing projection effects that have plagued previous optical cluster selection. The present C4 catalog covers {approx}2600 square degrees of sky and ranges in redshift from z = 0.02 to z = 0.17. The mean cluster membership is 36 galaxies (with redshifts) brighter than r = 17.7, but the catalog includes a range of systems, from groups containing 10 members to massive clusters with over 200 cluster members with redshifts. The catalog provides a large number of measured cluster properties including sky location, mean redshift, galaxy membership, summed r-band optical luminosity (L{sub r}), velocity dispersion, as well as quantitative measures of substructure and the surrounding large-scale environment. We use new, multi-color mock SDSS galaxy catalogs, empirically constructed from the {Lambda}CDM Hubble Volume (HV) Sky Survey output, to investigate the sensitivity of the C4 catalog to the various algorithm parameters (detection threshold, choice of passbands and search aperture), as well as to quantify the purity and completeness of the C4 cluster catalog. These mock catalogs indicate that the C4 catalog is {approx_equal}90% complete and 95% pure above M{sub 200} = 1 x 10{sup 14} h{sup -1}M{sub {circle_dot}} and within 0.03 {le} z {le} 0.12. Using the SDSS DR2 data, we show that the C4 algorithm finds 98% of X-ray identified clusters and 90% of Abell clusters within 0.03 {le} z {le} 0.12. Using the mock galaxy catalogs and the full HV dark matter simulations, we show that the L{sub r} of a cluster is a more robust estimator of the halo mass (M{sub 200}) than the galaxy line-of-sight velocity dispersion or the richness of the cluster

  7. Four-dimensional gravitational backgrounds based on N = 4, $\\widehat{c}$ = 4, superconformal systems

    CERN Document Server

    Kounnas, Costas

    1994-01-01

    We propose two new realizations of the N=4, $\\hat{c}=4$ superconformal system based on the compact and non-compact versions of parafermionic algebras. The target space interpretation of these systems is given in terms of four-dimensional target spaces with non-trivial metric and topology different from the previously known four-dimensional semi-wormhole realization. The proposed $\\hat{c}=4$ systems can be used as a building block to construct perturbatively stable superstring solutions with covariantized target space supersymmetry around non-trivial gravitational and dilaton backgrounds.

  8. A study of immunoglobulins and complements (C3 &C4 in alopecia areata

    Directory of Open Access Journals (Sweden)

    Sharma R

    1995-01-01

    Full Text Available Estimation of serum Immunoglobulins (IgG, IgM and IgA and complements (C3 and C4 was carried out in 100 cases of alopecia areata as per method described by Mancini (1965.[1] Clinically patients were divided in two groups, alopecia areata circumscribed (group I and severe alopecia areata (group II. Significant decrease in levels of one or more Immunoglobulins were observed in most of the patients. However, Serum complements (C3 and C4 were within range of normal control values

  9. C# 4, ASP.NET 4, and WPF, with Visual Studio 2010 jump start

    CERN Document Server

    Nagel, Christian; Stephens, Rod; Hanselman, Scott; Glynn, Jay; Rader, Devin; Watson, Karli; Skinner, Morgan

    2010-01-01

    This Wrox Blox is a value-packed resource to help experienced .NETdevelopers learn the new .NET release. It is excerpted from theWrox books: Professional C# 4 and .NET 4, Professional ASP.NET4, and WPF Programmer's Reference by Christian Nagel,Bill Evjen, Scott Hanselman, and Rod Stephens, and includes morethan 100 print book pages drawn from these three key titles. It isan excellent resource to help .NET developers get up to speed faston .NET 4, C# 4.0, ASP.NET 4, and WPF, providing all theinformation needed to program with the important new features,including: C# Dynamic Types and Par

  10. Effects of root applications of gibberellic acid on photosynthesis and growth in C3 and C 4 plants.

    Science.gov (United States)

    Tsai, D S; Arteca, R N

    1985-01-01

    The effects of root applications of gibberellic acid (GA3) on growth and photosynthesis of 12 species of plants including C3 monocots (Triticum aestivum L., wheat, Hordeum vulgare L., barley and Avena sativa L., oat), C3 dicots (Vigna radiata L., mung bean, Cucurbita moschata L., squash and Capsicum annuum L., pepper), C4 monocots (Zea mays L., corn, Sorghum vulgare L., sorghum and Panicum ramosum L., millet) and C4 dicots (Amaranthus retroflexus L., pigweed, Kochia scoparis L., kochia and Gomphrena celosoides L., gomphrena) were evaluated. Relative growth rates (RGR) of barley, oat, squash, pepper, corn, sorghum, millet, pigweed and kochia were increased above the control by 12.7%, 9.9%, 11.3%, 10.7%, 19.2% 10.1%, 11.5%, 16.4% and 32.7% respectively, four days following optimum GA3 treatments. There was no effect of GA3 on RGR in wheat, mung bean, and gomphrena. Gibberellic acid decreased the chlorophyll content expressed on an area basis by 20.0%, 13.9%, 20.9%, 17.1%, 11.9% and 28.0% in barley, squash, pepper, sorghum, pigweed and kochia, respectively, while that of oat, wheat, mung bean, corn, millet and gomphrena remained unchanged. When photosynthetic rates were expressed per mg of chlorophyll, it showed that GA3 could stimulate photosynthesis in barley, squash, pepper, sorghum, millet, pigweed and kochia by 20.4%, 20.6%, 16.5%, 17.4%, 10.4%, 24.2%, and 29.4%; while there was no effect in oat, wheat, mung bean, corn and gomphrena. An increase in leaf blade area and/or length of sheath were observed in GA3 treated plants of oat, barley, mung bean, squash, pepper, corn, sorghum, millet and kochia. The transpiration rate remained unchanged following GA3 treatment in all 12 species.

  11. C3 and C4 plant responses to increased temperatures and altered monsoonal precipitation in a cool desert on the Colorado Plateau, USA

    Science.gov (United States)

    Wertin, Timothy M.; Reed, Sasha C.; Belnap, Jayne

    2015-01-01

    Dryland ecosystems represent >40 % of the terrestrial landscape and support over two billion people; consequently, it is vital to understand how drylands will respond to climatic change. However, while arid and semiarid ecosystems commonly experience extremely hot and dry conditions, our understanding of how further temperature increases or altered precipitation will affect dryland plant communities remains poor. To address this question, we assessed plant physiology and growth at a long-term (7-year) climate experiment on the Colorado Plateau, USA, where the community is a mix of shallow-rooted C3 and C4 grasses and deep-rooted C4 shrubs. The experiment maintained elevated-temperature treatments (+2 or +4 °C) in combination with altered summer monsoonal precipitation (+small frequent precipitation events or +large infrequent events). Increased temperature negatively affected photosynthesis and growth of the C3 and C4 grasses, but effects varied in their timing: +4 °C treatments negatively affected the C3 grass early in the growing season of both years, while the negative effects of temperature on the C4 grass were seen in the +2 and +4 °C treatments, but only during the late growing season of the drier year. Increased summer precipitation did not affect photosynthesis or biomass for any species, either in the year the precipitation was applied or the following year. Although previous research suggests dryland plants, and C4 grasses in particular, may respond positively to elevated temperature, our findings from a cool desert show marked declines in C3 and C4 photosynthesis and growth, with temperature effects dependent on the degree of warming and growing-season precipitation.

  12. A Unique Model Platform for C4 Plant Systems and Synthetic Biology

    Science.gov (United States)

    2015-12-10

    agrobacterium mediated transformation 15. SUBJECT TERMS 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT Same as Report (SAR) 18. NUMBER OF...successful agrobacterium mediated transformation 15. SUBJECT TERMS synthetic biology, Systems Biology 16. SECURITY CLASSIFICATION OF...were obtained suggesting successful agrobacterium mediated transformation . Introduction: C4 plants such as sugarcane, maize and sorghum are more

  13. Contribution of root respiration to soil respiration in a C3/C4 mixed ...

    Indian Academy of Sciences (India)

    The spatial and temporal variations of soil respiration were studied from May 2004 to June 2005 in a C3/C4 mixed grassland of Japan. The linear regression relationship between soil respiration and root biomass was used to determine the contribution of root respiration to soil respiration. The highest soil respiration rate of ...

  14. Contribution of root respiration to soil respiration in a C3/C4 mixed ...

    Indian Academy of Sciences (India)

    Unknown

    The spatial and temporal variations of soil respiration were studied from May 2004 to June 2005 in a C3/C4 mixed grassland of Japan. The linear regression relationship between soil respiration and root biomass was used to determine the contribution of root respiration to soil respiration. The highest soil respiration rate of.

  15. Biochemical Characterization of the C-4-Dicarboxylate Transporter DctA from Bacillus subtilis

    NARCIS (Netherlands)

    Groeneveld, Maarten; Detert Oude Weme, Ruud; Duurkens, Ria H.; Slotboom, Dirk Jan

    Bacterial secondary transporters of the DctA family mediate ion-coupled uptake of C-4-dicarboxylates. Here, we have expressed the DctA homologue from Bacillus subtilis in the Gram-positive bacterium Lactococcus lactis. Transport of dicarboxylates in vitro in isolated membrane vesicles was assayed.

  16. Tomato yellow leaf curl virus C4 protein is a determinant of disease phenotype in tomato

    Science.gov (United States)

    Tomato yellow leaf curl virus (TYLCV) is a monopartite begomovirus. Its genome contains six open reading frames, with V1 and V2 in sense, and C1 to C4 in complementary orientation. The functions of V1 and V2 are for coat protein and pre-coat, respectively. C1 is for virus replication, C2 for trans-a...

  17. Combined C4d and CD3 immunostaining predicts immunoglobulin (Ig)A nephropathy progression

    NARCIS (Netherlands)

    Faria, B.; Henriques, C.; Matos, A. C.; Daha, M. R.; Pestana, M.; Seelen, M.

    A number of molecules have been shown recently to be involved in the pathogenesis and progression of immunoglobulin (Ig)A nephropathy (IgAN). Among these, we have selected C4d (complement lectin pathway involvement), CD3 (T cell marker, traducing interstitial inflammation), transglutaminase 2

  18. Thermomagnetic analysis of meteorites, 3. C3 and C4 chondrites

    Science.gov (United States)

    Herndon, J.M.; Rowe, M.W.; Larson, E.E.; Watson, D.E.

    1976-01-01

    Thermomagnetic analysis was made on samples of all known C3 and C4 chondrites in a controlled oxygen atmosphere. Considerable variation was noted in the occurrence of magnetic minerals, comparable to the variation observed earlier in the C2 chondrites. Magnetite was found as the only major magnetic phase in samples of only three C3 chondrites (2-4 wt.%) and the Karoonda C4 chondrite (7.7 wt.%). The magnetite content of these three C3 chondrites is only about one-third that observed in the C1 and C2 chondrites which were found to contain magnetite as the only magnetic phase. Five C3 chondrites were observed to undergo chemical change during heating, producing magnetite: this behavior is characteristic of troilite oxidation. Upper limits on initial magnetite content of about 1-9% were established for these meteorites. Samples of the remaining five C3 chondrites and the Coolidge C4 chondrite were found to contain both magnetite and metallic iron. In two samples, iron containing ???2% Ni was observed, while in the other four, the iron contained 6-8 wt.% Ni. In addition to containing both magnetite and iron metal, three of these samples reacted during heating to form additional magnetite. Variations in the magnetic mineralogy and, hence by inference bulk mineralogy, of C3 and C4 chondrites indicate a more complex genesis than is evident from whole-rock elemental abundance patterns. ?? 1976.

  19. Clinical significance of C4d in SLE and antiphospholipid syndrome

    NARCIS (Netherlands)

    Cohen, Danielle

    2012-01-01

    This thesis describes the clinical significance of thebiomarker C4d, a split product of the complement system, in several manifestations of systemic autoimmunediseases such as SLE and antiphospholipid syndrome. The findings in this thesis suggest that this biomarker might be of use in unraveling

  20. Identification of intermediates leading to chloroform and C-4 diacids in the chlorination of humic acid

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Leer, E.W.B. de; Erkelens, Corrie; Galan, L.

    1985-01-01

    The chlorination of terrestrial humic acid was studied at pH 7. 2 with varying chlorine to carbon ratios. The principal products are chloroform, di- and trichloroacetic acid, and chlorinated C-4 diacids. At a high chlorine dose many new chlorination products were detected, among them

  1. Electron swarm parameter measurements of perfluorobut-2-ene (2-C4F8)

    OpenAIRE

    Chachereau, Alise; Franck, Christian M.

    2015-01-01

    In this contribution, the electron swarm parameters of perfluorobut-2-ene (2-C4F8) mixtures with the buffer gases N2, CO2 and Argon are experimentally investigated. The effective ionization rate constant and electron drift velocity are measured in the entire E/N range up to the critical density-reduced electric field.

  2. Mathematical review of the energy transduction stoichiometries of C4 leaf photosynthesis under limiting light

    NARCIS (Netherlands)

    Yin, X.; Struik, P.C.

    2012-01-01

    A generalized model for electron (e-) transport limited C4 photosynthesis of NAD–malic enzyme and NADP–malic enzyme subtypes is presented. The model is used to review the thylakoid stoichiometries in vivo under strictly limiting light conditions, using published data on photosynthetic quantum yield

  3. Serum Complement C3 and C4 Levels in Relation to Diagnosis of ...

    African Journals Online (AJOL)

    Purpose: The main objective of this study was to measure serum complement C3 and C4 concentrations in patients of lupus nephritis to see if these simple measurements would give useful information to the clinician managing such patients.Method: A total of 52 samples were obtained from SLE patients, 17 suffering from ...

  4. PENERAPAN ALGORITMA C4.5 UNTUK PREDIKSI PENGGUNAAN JENIS KONTRASEPSI BERBASIS WEB

    Directory of Open Access Journals (Sweden)

    Rusda Wajhillah

    2017-09-01

    Keluarga Berencana (KB merupakan suatu program pemerintah yang dirancang untuk menyeimbangkan antara kebutuhan dan jumlah penduduk dengan menggunakan alat kontrasepsi. Kurangnya pengetahuan tentang kontrasepsi menyebabkan tidak sedikit akseptor lebih memilih menggunakan kontrasepsi berdasarkan coba-coba atau bahkan mengikuti saran dari orang lain yang kurang paham terhadap alat kontrasepsi. Oleh sebab itu, diperlukan adanya tindakan/penanganan khusus untuk mempermudah para akseptor dalam memilih kontrasepsi yang efektif dan sesuai dengan kondisi tubuhnya. Algoritma C4.5 yaitu metode pohon keputusan mengubah fakta yang sangat besar menjadi pohon keputusan yang merepresentasikan aturan. Aturan dapat dengan mudah dipahami dengan bahasa alami.Untuk itu, dalam penelitian ini akan dilakukan analisa data penggunaan jenis kontrasepsi menggunakan klasifikasi data mining yakni algoritma C4.5 dengan menggunakan beberapa parameter diantaranya usia, jumlah anak, tekanan darah dan riwayat penyakit yang akan diaplikasikan dalam bentuk web guna mempermudah para akseptor dalam mendapatkan nilai informasi yang lebih cepat dan fleksibel. Dari 130 jumlah kasus yang terdiri dari 104 kasus akseptor pengguna kontrasepsi hormonal dan 26 kasus pengguna kontrasepsi non hormonal yang didapat dari Posyandu Desa Nyangkowek Kecamatan Cicurug, maka didapatkan 14 rule yang dihasilkan dari pohon keputusan algoritma C4.5 dengan jumlah class non hormonal sebanyak 8 rule dan jumlah class hormonal sebanyak 6 rule serta dievaluasi dengan pengujian Cross Validation yangmenghasilkan tingkat akurasi sebesar 85,38%, sehingga dapat disimpulkan bahwa penelitian ini dapat membantu para akseptor KB dalam memilih jenis kontrasepsi yang efektif. Kata Kunci: Akseptor, Algoritma C4.5, Kontrasepsi, Sistem Pakar

  5. Epitaxial Stabilization between Intermetallic and Carbide Domains in the Structures of Mn16SiC4 and Mn17Si2C4.

    Science.gov (United States)

    Fredrickson, Rie T; Guo, Yiming; Fredrickson, Daniel C

    2016-01-13

    The concept of frustration between competing geometrical or bonding motifs is frequently evoked in explaining complex phenomena in the structures and properties of materials. This idea is of particular importance for metallic systems, where frustration forms the basis for the design of metallic glasses, a source of diverse magnetic phenomena, and a rationale for the existence of intermetallics with giant unit cells containing thousands of atoms. Unlike soft materials, however, where conflicts can be synthetically encoded in the molecular structure, staging frustration in the metallic state is challenging due to the ease of macroscopic segregation of incompatible components. In this Article, we illustrate one approach for inducing the intergrowth of incompatible bonding motifs with the synthesis and characterization of two new intermetallic carbides: Mn16SiC4 (mC42) and Mn17Si2C4 (mP46). Similar to the phases Mn5SiC and Mn8Si2C in the Mn-Si-C system, these compounds appear as intergrowths of Mn3C and tetrahedrally close-packed (TCP) regions reminiscent of Mn-rich Mn-Si phases. The nearly complete spatial segregation of Mn-Si (intermetallic) and Mn-C (carbide) interactions in these structures can be understood from the differing geometrical requirements of C and Si. Rather than macroscopically separating into distinct phases, though, the two bonding types are tightly interwoven, with most Mn atoms being on the interfaces. DFT chemical pressure analysis reveals a driving force stabilizing these interfaces: the major local pressures acting between the Mn atoms in the Mn-Si and Mn-C systems are of opposite signs. Joining the intermetallic and carbide domains together then provides substantial relief to these local pressures, an effect we term epitaxial stabilization.

  6. 40 CFR 721.10103 - Naphtha (Fischer-Tropsch), C4-11-alkane, branched and linear.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Naphtha (Fischer-Tropsch), C4-11... Significant New Uses for Specific Chemical Substances § 721.10103 Naphtha (Fischer-Tropsch), C4-11-alkane... substance identified as naphtha (fischer-tropsch), C4-11-alkane, branched and linear (PMN P-04-235; CAS No...

  7. C4.4A gene ablation is compatible with normal epidermal development and causes modest overt phenotypes

    DEFF Research Database (Denmark)

    Kriegbaum, Mette Camilla; Jacobsen, Benedikte; Füchtbauer, Annette

    2016-01-01

    of C4.4A in normal physiology and cancer progression. The unchallenged C4.4A-deficient mice were viable, fertile, born in a normal Mendelian distribution and, surprisingly, displayed normal development of squamous epithelia. The C4.4A-deficient mice were, nonetheless, significantly lighter than...

  8. Eliminating false positive C4 sugar tests on New Zealand Manuka honey.

    Science.gov (United States)

    Rogers, Karyne M; Somerton, Kerry; Rogers, Pamela; Cox, Julie

    2010-08-30

    Carbon isotope analyses (delta(13)C) of some New Zealand Manuka honeys show that they often fail the internationally recognised Association of Official Analytical Chemists sugar test (AOAC method 998.12) which detects added C(4) sugar, although these honeys are from unadulterated sources. Failure of these high value products is detrimental to the New Zealand honey industry, not only in lost export revenue, but also in brand and market reputation damage. The standard AOAC test compares the carbon isotope value of the whole honey and corresponding protein isolated from the same honey. Differences between whole honey and protein delta(13)C values should not be greater than +1.0 per thousand, as it indicates the possibility of adulteration with syrups or sugars from C(4) plants such as high fructose corn syrup or cane sugar.We have determined that during the standard AOAC method, pollen and other insoluble components are isolated with the flocculated protein. These non-protein components have isotope values which are considerably different from those of the pure protein, and can shift the apparent delta(13)C value of protein further away from the delta(13)C value of the whole honey, giving a false positive result for added C(4) sugar. To eliminate a false positive C(4) sugar test for Manuka honey, prior removal of pollen and other insoluble material from the honey is necessary to ensure that only the pure protein is isolated. This will enable a true comparison between whole honey and protein delta(13)C isotopes. Furthermore, we strongly suggest this modification to the AOAC method be universally adopted for all honey C(4) sugar tests. 2010 John Wiley & Sons, Ltd.

  9. Testis-Specific Lactate Dehydrogenase (LDH-C4 in Skeletal Muscle Enhances Apika’s Sprint-Running Capacity in Hypoxic Environment

    Directory of Open Access Journals (Sweden)

    Yang Wang

    2015-08-01

    Full Text Available LDH-C4 is a lactate dehydrogenase that catalyzes the conversion of pyruvate to lactate. In mammals, ldh-c was originally thought to be expressed only in testis and spermatozoa. Plateau pika (Ochotona curzoniae, which belongs to the genus Ochotona of the Ochotonidea family, is a hypoxia tolerant mammal living 3000–5000 m above sea level on the Qinghai-Tibet Plateau, an environment which is strongly hypoxic. Ldh-c is expressed not only in testis and sperm but also in somatic tissues of plateau pika. In this study, the effects of N-propyl oxamate and N-isopropyl oxamate on LDH isozyme kinetics were compared to screens for a selective inhibitor of LDH-C4. To reveal the role and physiological mechanism of LDH-C4 in skeletal muscle of plateau pika, we investigated the effect of N-isopropyl oxamate on the pika exercise tolerance as well as the physiological mechanism. Our results show that Ki of N-propyl oxamate and N-isopropyl oxamate for LDH-A4, LDH-B4, and LDH-C4 were 0.094 mmol/L and 0.462 mmol/L, 0.119 mmol/L and 0.248 mmol/L, and 0.015 mmol/L and 0.013 mmol/L, respectively. N-isopropyl oxamate is a powerful selective inhibitor of plateau pika LDH-C4. In our exercise tolerance experiment, groups treated with inhibitors had significantly lower swimming times than the uninhibited control group. The inhibition rates of LDH, LD, and ATP were 37.12%, 66.27%, and 32.42%, respectively. Our results suggested that ldh-c is expressed in the skeletal muscle of plateau pika, and at least 32.42% of ATP in the skeletal muscle is catalyzed by LDH-C4 by anaerobic glycolysis. This suggests that pika has reduced dependence on oxygen and enhanced adaptation to hypoxic environment due to increased anaerobic glycolysis by LDH-C4 in skeletal muscle. LDH-C4 in plateau pika plays the crucial role in anaerobic glycolysis and generates ATP rapidly since this is the role of LDH-A4 in most species on plain land, which provide evidence that the native humans and animals in

  10. Spectral resampling based on user-defined interband correlation filter: C3 and C4 grass species classification

    CSIR Research Space (South Africa)

    Adjorlolo, C

    2013-04-01

    Full Text Available accounted for. In this regard, a more innovative approach can be followed, whereby the 10 researchers consider the inter-band correlations around each band centre of interest. The 11 approach has the advantage of linking the physical properties... airborne hyperspectral imagery. Remote Sensing of Environment, 112(6): 2999-3011. 19 Chi, M. and Bruzzone, L., 2007. Semisupervised classification of hyperspectral images by 20 SVMs optimized in the primal. Geoscience and Remote Sensing, IEEE Transactions...

  11. Structural Basis for the Function of Complement Component C4 within the Classical and Lectin Pathways of Complement

    DEFF Research Database (Denmark)

    Mortensen, Sofia; Kidmose, Rune Thomas; Petersen, Steen Vang

    2015-01-01

    Complement component C4 is a central protein in the classical and lectin pathways within the complement system. During activation of complement, its major fragment C4b becomes covalently attached to the surface of pathogens and altered self-tissue, where it acts as an opsonin marking the surface...... for removal. Moreover, C4b provides a platform for assembly of the proteolytically active convertases that mediate downstream complement activation by cleavage of C3 and C5. In this article, we present the crystal and solution structures of the 195-kDa C4b. Our results provide the molecular details...... of the rearrangement accompanying C4 cleavage and suggest intramolecular flexibility of C4b. The conformations of C4b and its paralogue C3b are shown to be remarkably conserved, suggesting that the convertases from the classical and alternative pathways are likely to share their overall architecture and mode...

  12. Clinical and pathological correlations of C4d immunostaining and its infl uence on the outcome of kidney transplant recipients

    Directory of Open Access Journals (Sweden)

    Virna Nowotny Carpio

    2011-09-01

    Full Text Available INTRODUCTION: C4d is a marker of antibody-mediated rejection (ABMR in kidney allografts, although cellular rejection also have C4d deposits. OBJECTIVE: To correlate C4d expression with clinico-pathological parameters and graft outcomes at three years. METHODS: One hundred forty six renal transplantation recipients with graft biopsies by indication were included. C4d staining was performed by paraffin-immunohistochemistry. Graft function and survival were measured, and predictive variables of the outcome were determined by multivariate Cox regression. RESULTS: C4d staining was detected in 48 (31% biopsies, of which 23 (14.7% had diffuse and 25 (16% focal distribution. Pre-transplantation panel reactive antibodies (%PRA class I and II were significantly higher in C4d positive patients as compared to those C4d negative. Both glomerulitis and pericapillaritis were associated to C4d (p = 0.002 and p < 0.001, respectively. The presence of C4d in biopsies diagnosed as no rejection (NR, acute cellular rejection (ACR or interstitial fibrosis/ tubular atrophy (IF/TA did not impact graft function or survival. Compared to NR, ACR and IF/TA C4d-, patients with ABMR C4d+ had the worst graft survival over 3 years (p = 0.034, but there was no difference between ABMR versus NR, ACR and IF/TA that were C4d positive (p = 0.10. In Cox regression, graft function at biopsy and high %PRA levels were predictors of graft loss. CONCLUSIONS: This study confirmed that C4d staining in kidney graft biopsies is a clinically useful marker of ABMR, with well defined clinical and pathological correlations. The impact of C4d deposition in other histologic diagnoses deserves further investigation.

  13. Previable Preeclampsia Diagnosed by Renal Biopsy in Setting of Novel Diagnosis of C4 Glomerulopathy

    Directory of Open Access Journals (Sweden)

    Jessica Parrott

    2017-01-01

    Full Text Available Background. Preeclampsia diagnosed before 20 weeks’ gestational age is a rare entity, particularly without any predisposing factors. We report a case of preeclampsia occurring prior to 20 weeks’ gestational age in the setting of a novel diagnosis of C4 glomerulopathy. Case. A G3P0020 at 18 weeks presented with new onset hypertension and proteinuria, requiring multiple antihypertensive agents to maintain control. Renal biopsy demonstrated thrombotic microangiopathic lesions and glomerular endotheliosis. C4-dominant staining and numerous subendothelial and mesangial electron dense deposits were found within the glomerulus. With no other definable etiologies, preeclampsia was diagnosed. She developed posterior reversible encephalopathic syndrome and pregnancy termination was recommended. Conclusion. The lectin complement pathway may play a role in the pathophysiology of severe, early onset preeclampsia. Renal biopsy may play an integral role in diagnosis.

  14. Threshold Studies on TNT, Composition B, and C-4 Explosives Using the Steven Impact Test

    Energy Technology Data Exchange (ETDEWEB)

    Vandersall, K S; Switzer, L L; Garcia, F

    2005-09-26

    Steven Impact Tests were performed at low velocity on the explosives TNT, Comp B, and C-4 in attempts to obtain a threshold for reaction. A 76 mm helium driven gas gun was used to accelerate the Steven Test projectiles up to approximately 200 m/s in attempts to react (ignite) the explosive samples. Blast overpressure gauges, acoustic microphones, standard video and high-speed photography were used to characterize the level of any high explosive reaction violence. No bulk reactions were observed in the TNT, Composition B, or C-4 explosive samples impacted up to velocities in the range of 190-200 m/s. This work will outline the experimental details and discuss the lack of reaction when compared to the reaction thresholds of other common explosives.

  15. Long-lived transient anion of c-C4F8O

    Science.gov (United States)

    Kočišek, J.; Janečková, R.; Fedor, J.

    2018-02-01

    We report partial cross sections for electron attachment to c-C4F8O, a gas with promising technological applications in free-electron-rich environments. The dissociative electron attachment leads to a number of anionic fragments resulting from complex bond-breaking and bond-forming processes. However, the anion with the highest abundance is the non-dissociated (transient) parent anion which is formed around 0.9 eV electron energy. Its lifetime reaches tens of microseconds. We discuss the origin of this long lifetime, the anion's strong interactions with other molecules, and the consequences for electron-scavenging properties of c-C4F8O in denser environments, in particular for its use in mixtures with CO2 and N2.

  16. C4.4A as a biomarker in pulmonary adenocarcinoma and squamous cell carcinoma

    DEFF Research Database (Denmark)

    Jacobsen, Benedikte; Kriegbaum, Mette Camilla; Santoni-Rugiu, Eric

    2014-01-01

    The high prevalence and mortality of lung cancer, together with a poor 5-year survival of only approximately 15%, emphasize the need for prognostic and predictive factors to improve patient treatment. C4.4A, a member of the Ly6/uPAR family of membrane proteins, qualifies as such a potential...... informative biomarker in non-small cell lung cancer. Under normal physiological conditions, it is primarily expressed in suprabasal layers of stratified squamous epithelia. Consequently, it is absent from healthy bronchial and alveolar tissue, but nevertheless appears at early stages in the progression...... to invasive carcinomas of the lung, i.e., in bronchial hyperplasia/metaplasia and atypical adenomatous hyperplasia. In the stages leading to pulmonary squamous cell carcinoma, expression is sustained in dysplasia, carcinoma in situ and invasive carcinomas, and this pertains to the normal presence of C4.4A...

  17. C4BPAL1, a member of the human regulator of complement activation (RCA) gene cluster that resulted from the duplication of the gene coding for the [alpha]-chain of C4b-binding protein

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez-Corral, P.; Pardo-Manuel de Villena, F.; Rey-Campos, J.; Rodriguez de Cordoba, S. (Unidad de Immunologia, Madrid (Spain))

    1993-07-01

    The regulator of complement activation (RCA) gene cluster evolved by multiple gene duplications to produce a family of genes coding for proteins that collectively control the activation of the complement system. The authors report here the characterization of C4BPAL1, a member of the human RCA gene cluster that arose from the duplication of the C4BPA gene after the separation of rodent and primate lineages. C4BPAL1 maps 20 kb downstream of the C4BPA gene and is in the same 5[prime] to 3[prime] orientation found for all RCA genes characterized thus far. It includes nine exon-like regions homologous to exons 2-8, 11, and 12 of the C4BPA gene. Analysis of the C4BPAL1 sequence suggests that it is currently a pseudogene in humans. However, comparisons between C4BPAL1 and the human and murine C4BPA genes show sequence conservation, which strongly suggests that, for a long period of time, C4BPAL1 has been a functional gene coding for a protein with structural requirements similar to those of the [alpha]-chain of C4b-binding protein. 50 refs., 5 figs., 1 tab.

  18. Combined C4d and CD3 immunostaining predicts immunoglobulin (Ig)A nephropathy progression.

    Science.gov (United States)

    Faria, B; Henriques, C; Matos, A C; Daha, M R; Pestana, M; Seelen, M

    2015-02-01

    A number of molecules have been shown recently to be involved in the pathogenesis and progression of immunoglobulin (Ig)A nephropathy (IgAN). Among these, we have selected C4d (complement lectin pathway involvement), CD3 (T cell marker, traducing interstitial inflammation), transglutaminase 2 (TGase-2, involved in tissue fibrosis development) and p-extracelluar-regulated kinase (ERK)1/2 (protein kinase intracellular signaling molecule) to perform a panel of immunohistological biomarkers and assess its predictive value for disease progression. Immunohistochemical staining of these biomarkers was performed in paraffin sections from 74 renal biopsy cases with the clinical diagnosis of IgAN. Association between score analysis of these parameters and disease course was assessed through univariate and multivariate analysis, including baseline clinical and histological data. Univariate analysis showed that glomerular C4d, tubulointerstitial TGase2 and CD3 scores were associated with baseline proteinuria and disease progression. Multivariate analysis showed that only baseline estimated glomerular filtration rate (eGFR), C4d and CD3 were associated independently with progressive kidney disease (decline of at least 50% in the eGFR or progression to end-stage renal disease (ESRD) during the follow-up period). Establishing an accurate prediction model for IgAN progression is still a matter of research in clinical nephrology. The complement system, particularly lectin pathway activation, and T cell activation, have been shown previously to be potential modifiers of the disease course. Here we show that the combination of two histological biomarkers (C4d and CD3) can be a powerful predictor of IgAN progression and a potential useful tool for the clinical approach of this disease. © 2014 British Society for Immunology.

  19. Electrophile-Integrating Smiles Rearrangement Provides Previously Inaccessible C4?-O-Alkyl Heptamethine Cyanine Fluorophores

    OpenAIRE

    Nani, Roger R.; Shaum, James B.; Gorka, Alexander P.; Schnermann, Martin J.

    2015-01-01

    New synthetic methods to rapidly access useful fluorophores are needed to advance modern molecular imaging techniques. A new variant of the classical Smiles rearrangement is reported that enables the efficient synthesis of previously inaccessible C4?-O-alkyl heptamethine cyanines. The key reaction involves N- to O- transposition with selective electrophile incorporation on nitrogen. A representative fluorophore exhibits excellent resistance to thiol nucleophiles, undergoes productive bioconju...

  20. Electrophile-integrating Smiles rearrangement provides previously inaccessible C4'-O-alkyl heptamethine cyanine fluorophores.

    Science.gov (United States)

    Nani, Roger R; Shaum, James B; Gorka, Alexander P; Schnermann, Martin J

    2015-01-16

    New synthetic methods to rapidly access useful fluorophores are needed to advance modern molecular imaging techniques. A new variant of the classical Smiles rearrangement is reported that enables the efficient synthesis of previously inaccessible C4'-O-alkyl heptamethine cyanines. The key reaction involves N- to O-transposition with selective electrophile incorporation on nitrogen. A representative fluorophore exhibits excellent resistance to thiol nucleophiles, undergoes productive bioconjugation, and can be used in near-IR fluorescence imaging applications.

  1. Polygonumnolides C1-C4; minor dianthrone glycosides from the roots of Polygonum multiflorum Thunb.

    Science.gov (United States)

    Yang, Jian-Bo; Li, Li; Dai, Zhong; Wu, Yu; Geng, Xing-Chao; Li, Bo; Ma, Shuang-Cheng; Wang, Ai-Guo; Su, Ya-Lun

    2016-09-01

    Four new dianthrone glycosides, named polygonumnolides C1-C4 (1-4), were isolated from the dried roots of Polygonum multiflorum Thunb, together with two known emodin dianthrones (5-6). Their hepatotoxicities were evaluated against L-02 cell lines. Compounds 1-4 showed weak hepatotoxicity against L-02 cell lines with IC50 values of 313.05, 205.20, 294.20, and 207.35 μM, respectively.

  2. Silver(I)-Catalyzed C4-H Amination of 1-Naphthylamine Derivatives with Azodicarboxylates.

    Science.gov (United States)

    Zhu, Hongmei; Sun, Suyan; Qiao, Huijie; Yang, Fan; Kang, Jianxun; Wu, Yusheng; Wu, Yangjie

    2018-02-02

    A simple and efficient protocol for silver(I)-catalyzed picolinamide directed C4-H amination of 1-naphthylamine derivatives with readily available azodicarboxylates has been developed, demonstrating a new approach to 1,4-naphthalenediamine derivatives in high yields. Note that this reaction system could proceed under external-oxidant- and additive-free conditions (only requires 5 mol % of AgOAc as the catalyst in acetone).

  3. What is the behavior of a C4 quadriplegic mouth calligrapher constant function of?

    Directory of Open Access Journals (Sweden)

    Nonaka Tetsushi

    2011-12-01

    Full Text Available Motor coordination of a professional C4 quadriplegic calligrapher who trained himself to use his mouth to write with brush and ink by gripping a brush between his teeth was reported. Through the analysis of movement during calligraphy, it was found that the movement variability of the head-neck system was exploited to stabilize certain relations between the brush and the paper surface (e.g., brush pressure.

  4. What is the behavior of a C4 quadriplegic mouth calligrapher constant function of?

    OpenAIRE

    Nonaka Tetsushi

    2011-01-01

    Motor coordination of a professional C4 quadriplegic calligrapher who trained himself to use his mouth to write with brush and ink by gripping a brush between his teeth was reported. Through the analysis of movement during calligraphy, it was found that the movement variability of the head-neck system was exploited to stabilize certain relations between the brush and the paper surface (e.g., brush pressure).

  5. CO2 enrichment inhibits shoot nitrate assimilation in C3 but not C4 plants and slows growth under nitrate in C3 plants.

    Science.gov (United States)

    Bloom, Arnold J; Asensio, Jose Salvador Rubaio; Randall, Lesley; Rachmilevitch, Shimon; Cousins, Asaph B; Carlisle, Eli A

    2012-02-01

    The CO2 concentration in Earth's atmosphere may double during this century. Plant responses to such an increase depend strongly on their nitrogen status, but the reasons have been uncertain. Here, we assessed shoot nitrate assimilation into amino acids via the shift in shoot CO2 and O2 fluxes when plants received nitrate instead of ammonium as a nitrogen source (deltaAQ). Shoot nitrate assimilation became negligible with increasing CO2 in a taxonomically diverse group of eight C3 plant species, was relatively insensitive to CO2 in three C4 species, and showed an intermediate sensitivity in two C3-C4 intermediate species. We then examined the influence of CO2 level and ammonium vs. nitrate nutrition on growth, assessed in terms of changes in fresh mass, of several C3 species and a Crassulacean acid metabolism (CAM) species. Elevated CO2 (720 micromol CO2/mol of all gases present) stimulated growth or had no effect in the five C3 species tested when they received ammonium as a nitrogen source but inhibited growth or had no effect if they received nitrate. Under nitrate, two C3 species grew faster at sub-ambient (approximately 310 micromol/mol) than elevated CO2. A CAM species grew faster at ambient than elevated or sub-ambient CO2 under either ammonium or nitrate nutrition. This study establishes that CO2 enrichment inhibits shoot nitrate assimilation in a wide variety of C3 plants and that this phenomenon can have a profound effect on their growth. This indicates that shoot nitrate assimilation provides an important contribution to the nitrate assimilation of an entire C3 plant. Thus, rising CO2 and its effects on shoot nitrate assimilation may influence the distribution of C3 plant species.

  6. The welding metallurgy of HASTELLOY alloys C-4, C-22, and C-276

    Science.gov (United States)

    Cieslak, M. J.; Headley, T. J.; Romig, A. D.

    1986-11-01

    The welding metallurgy (solidification and solid state transformations) of HASTELLOY* Alloys C-4, C-22, and C-276 has been determined. Varestraint hot-cracking tests performed on commercial alloys revealed a weldability ranking as follows: C-4 > C-22 > C-276. All alloys would be expected to have good weldability, with Alloy C-4 having a very low hot-cracking tendency, comparable to 304L stainless steel. Microstructures of gas-tungsten-arc welds of these alloys have been characterized by scanning electron microscopy and analytical electron microscopy. Intermetallic secondary solidification constituents have been found associated with weld metal hot cracks in Alloys C-276 and C-22. In Alloy C-276, this constituent is a combination of P and ώ phases, and in Alloy C-22, this constituent is composed of σ, P, and ώ phases. With phase composition data obtained by AEM techniques and available ternary (Ni-Cr-Mo) phase diagrams, an equivalent chemistry model is proposed to account for the microstructures observed in each alloy's weld metal.

  7. Increasing leaf vein density by mutagenesis: laying the foundations for C4 rice.

    Directory of Open Access Journals (Sweden)

    Aryo B Feldman

    Full Text Available A high leaf vein density is both an essential feature of C4 photosynthesis and a foundation trait to C4 evolution, ensuring the optimal proportion and proximity of mesophyll and bundle sheath cells for permitting the rapid exchange of photosynthates. Two rice mutant populations, a deletion mutant library with a cv. IR64 background (12,470 lines and a T-DNA insertion mutant library with a cv. Tainung 67 background (10,830 lines, were screened for increases in vein density. A high throughput method with handheld microscopes was developed and its accuracy was supported by more rigorous microscopy analysis. Eight lines with significantly increased leaf vein densities were identified to be used as genetic stock for the global C4 Rice Consortium. The candidate population was shown to include both shared and independent mutations and so more than one gene controlled the high vein density phenotype. The high vein density trait was found to be linked to a narrow leaf width trait but the linkage was incomplete. The more genetically robust narrow leaf width trait was proposed to be used as a reliable phenotypic marker for finding high vein density variants in rice in future screens.

  8. Differential timing of C4 plant decline and grassland retreat during the penultimate deglaciation

    Science.gov (United States)

    He, Juan; Jia, Guodong; Li, Li; Wang, Pinxian

    2017-09-01

    Compound-specific stable carbon isotope composition of terrestrial leaf wax n-alkyl lipids (δ13Calk) was measured in sediments from the northern South China Sea (SCS), allowing assessment of vegetation change in the source area within the penultimate glacial cycle during 60-160 kyr. Our δ13Calk record suggested a prominent vegetation contrast between the glacial and the interglacial, with more C4 plant developing during the glaciation and a rapid decline during the glacial termination. This deglacial change in δ13Calk was attributed to an increase in humidity caused by the enhancement of the East Asian Summer Monsoon (EASM). However, the inferred deglacial C4 decline lagged by 4 kyr behind the grass retreat inferred from published pollen record. We argue that the time discrepancy in the two terrestrial plant proxies may have resulted from their differential responses to regional climate change, with grass community structure more sensitive to temperature rise and plant photosynthetic pathway more sensitive to humidity increase. Therefore, an earlier penultimate deglacial warming relative to humidity increase can be inferred from the lead of grass retreat relative to C4 decline, which implies that EASM may be delayed during the deglacial warming.

  9. Amygdalin inhibits genes related to cell cycle in SNU-C4 human colon cancer cells.

    Science.gov (United States)

    Park, Hae-Jeong; Yoon, Seo-Hyun; Han, Long-Shan; Zheng, Long-Tai; Jung, Kyung-Hee; Uhm, Yoon-Kyung; Lee, Je-Hyun; Jeong, Ji-Seon; Joo, Woo-Sang; Yim, Sung-Vin; Chung, Joo-Ho; Hong, Seon-Pyo

    2005-09-07

    The genes were divided into seven categories according to biological function; apoptosis-related, immune response-related, signal transduction-related, cell cycle-related, cell growth-related, stress response-related and transcription-related genes. We compared the gene expression profiles of SNU-C4 cells between amygdalin-treated (5 mg/mL, 24 h) and non-treated groups using cDNA microarray analysis. We selected genes downregulated in cDNA microarray and investigated mRNA levels of the genes by RT-PCR. Microarray showed that amygdalin downregulated especially genes belonging to cell cycle category: exonuclease 1 (EXO1), ATP-binding cassette, sub-family F, member 2 (ABCF2), MRE11 meiotic recombination 11 homolog A (MRE11A), topoisomerase (DNA) I (TOP1), and FK506 binding protein 12-rapamycin-associated protein 1 (FRAP1). RT-PCR analysis revealed that mRNA levels of these genes were also decreased by amygdalin treatment in SNU-C4 human colon cancer cells. These results suggest that amygdalin have an anticancer effect via downregulation of cell cycle-related genes in SNU-C4 human colon cancer cells, and might be used for therapeutic anticancer drug.

  10. The superfamily of C3b/C4b-binding proteins

    DEFF Research Database (Denmark)

    Kristensen, Torsten; D'Eustachio, P; Ogata, R T

    1987-01-01

    The determination of primary structures by amino acid and nucleotide sequencing for the C3b-and/or C4b-binding proteins H, C4BP, CR1, B, and C2 has revealed the presence of a common structural element. This element is approximately 60 amino acids long and is repeated in a tandem fashion, commencing...... at the amino-terminal end of each molecule. Two other complement components, C1r and C1s, have two of these repeating units in the carboxy-terminal region of their noncatalytic A chains. Three noncomplement proteins, beta 2-glycoprotein I (beta 2I), the interleukin 2 receptor (IL 2 receptor), and the b chain...... of factor XIII, have 4, 2 and 10 of these repeating units, respectively. These proteins obviously belong to the above family, although there is no evidence that they interact with C3b and/or C4b. Human haptoglobin and rat leukocyte common antigen also contain two and three repeating units, respectively...

  11. Serum antibodies and cytokines in C4-deficient mice and their responses to exercise.

    Science.gov (United States)

    Visetnoi, Supawan; Chawengkirttikul, Runglawan; Chaiyaroj, Sansanee C; Kitiyanant, Yindee; Pholpramool, Chumpol

    2009-12-01

    Psychological stress is believed to be one of the predisposing factors for systemic lupus erythematosus (SLE), whereas physical stress such as exercise has never been reported to be related. We measured the circulating levels of antibodies (IgM, IgG, anti-dsDNA IgG), Th1 (IFN-gamma), Th2 (IL-4, IL-6), and of pro-inflammatory (TNF-alpha, IL-1beta) and anti-inflammatory (TGF-beta) cytokines of C4(-l-) female mice at rest, after acute exercise and after exercise training, using an antibody-capture ELISA. Prior to the exercise, the C4(-l-) mice had higher levels of IgG and anti-dsDNA IgG but lower levels of IFN-gamma, IL-1beta, IL-6 and IL-4 than wild-type C57BL/6 (B6) mice. A single bout of exercise to exhaustion increased serum IgG, TNF-alpha, IL-1beta and TGF-beta in the B6 mice but only TGF-beta in the C4(-l-) mice was increased. We conclude that exhaustive or moderate exercise has no effect on the levels of serum antibodies and cytokines and is thus unlikely to promote the onset of SLE.

  12. Duplication and Loss of Function of Genes Encoding RNA Polymerase III Subunit C4 Causes Hybrid Incompatibility in Rice

    Directory of Open Access Journals (Sweden)

    Giao Ngoc Nguyen

    2017-08-01

    Full Text Available Reproductive barriers are commonly observed in both animals and plants, in which they maintain species integrity and contribute to speciation. This report shows that a combination of loss-of-function alleles at two duplicated loci, DUPLICATED GAMETOPHYTIC STERILITY 1 (DGS1 on chromosome 4 and DGS2 on chromosome 7, causes pollen sterility in hybrid progeny derived from an interspecific cross between cultivated rice, Oryza sativa, and an Asian annual wild rice, O. nivara. Male gametes carrying the DGS1 allele from O. nivara (DGS1-nivaras and the DGS2 allele from O. sativa (DGS2-T65s were sterile, but female gametes carrying the same genotype were fertile. We isolated the causal gene, which encodes a protein homologous to DNA-dependent RNA polymerase (RNAP III subunit C4 (RPC4. RPC4 facilitates the transcription of 5S rRNAs and tRNAs. The loss-of-function alleles at DGS1-nivaras and DGS2-T65s were caused by weak or nonexpression of RPC4 and an absence of RPC4, respectively. Phylogenetic analysis demonstrated that gene duplication of RPC4 at DGS1 and DGS2 was a recent event that occurred after divergence of the ancestral population of Oryza from other Poaceae or during diversification of AA-genome species.

  13. Elevated atmospheric CO2 triggers compensatory feeding by root herbivores on a C3 but not a C4 grass.

    Directory of Open Access Journals (Sweden)

    Scott N Johnson

    Full Text Available Predicted increases in atmospheric carbon dioxide (CO2 concentrations often reduce nutritional quality for herbivores by increasing the C:N ratio of plant tissue. This frequently triggers compensatory feeding by aboveground herbivores, whereby they consume more shoot material in an attempt to meet their nutritional needs. Little, however, is known about how root herbivores respond to such changes. Grasslands are particularly vulnerable to root herbivores, which can collectively exceed the mass of mammals grazing aboveground. Here we provide novel evidence for compensatory feeding by a grass root herbivore, Sericesthis nigrolineata, under elevated atmospheric CO2 (600 µmol mol(-1 on a C3 (Microlaena stipoides but not a C4 (Cymbopogon refractus grass species. At ambient CO2 (400 µmol mol(-1 M. stipoides roots were 44% higher in nitrogen (N and 7% lower in carbon (C concentrations than C. refractus, with insects performing better on M. stipoides. Elevated CO2 decreased N and increased C:N in M. stipoides roots, but had no impact on C. refractus roots. Root-feeders displayed compensatory feeding on M. stipoides at elevated CO2, consuming 118% more tissue than at ambient atmospheric CO2. Despite this, root feeder biomass remained depressed by 24%. These results suggest that compensatory feeding under elevated atmospheric CO2 may make some grass species particularly vulnerable to attack, potentially leading to future shifts in the community composition of grasslands.

  14. Anomalous 13C isotope abundances in C3S and C4H observed toward the cold interstellar cloud, Taurus Molecular Cloud-1.

    Science.gov (United States)

    Sakai, Nami; Takano, Shuro; Sakai, Takeshi; Shiba, Shoichi; Sumiyoshi, Yoshihiro; Endo, Yasuki; Yamamoto, Satoshi

    2013-10-03

    We have studied the abundances of the (13)C isotopic species of C3S and C4H in the cold molecular cloud, Taurus Molecular Cloud-1 (Cyanopolyyne Peak), by radioastronomical observations of their rotational emission lines. The CCCS/(13)CCCS and CCCS/C(13)CCS ratios are determined to be >206 and 48 ± 15, respectively. The CC(13)CS line is identified with the aid of laboratory microwave spectroscopy, and the range of the CCCS/CC(13)CS ratio is found to be from 30 to 206. The abundances of at least two (13)C isotopic species of C3S are thus found to be different. Similarly, it is found that the abundances of the four (13)C isotopic species of C4H are not equivalent. The CCCCH/(13)CCCCH, CCCCH/C(13)CCCH, CCCCH/CC(13)CCH, and CCCCH/CCC(13)CH ratios are evaluated to be 141 ± 44, 97 ± 27, 82 ± 15, and 118 ± 23, respectively. Here the errors denote 3 times the standard deviation. These results will constrain the formation pathways of C3S and C4H, if the nonequivalence is caused during the formation processes of these molecules. The exchange reactions after the formation of these two molecules may also contribute to the nonequivalence. In addition, we have confirmed that the (12)C/(13)C ratio of some species are significantly higher than the interstellar elemental (12)C/(13)C ratio of 60-70. The observations of the (13)C isotopic species provide us with rich information on chemical processes in cold interstellar clouds.

  15. Low C4 gene copy numbers are associated with superior graft survival in patients transplanted with a deceased donor kidney

    DEFF Research Database (Denmark)

    Bay, Jakob T; Schejbel, Lone; Madsen, Hans O

    2013-01-01

    rejection, but a relationship between graft survival and serum C4 concentration as well as C4 genetic variation has not been established. We evaluated this using a prospective study design of 676 kidney transplant patients and 211 healthy individuals as controls. Increasing C4 gene copy numbers...... significantly correlated with the C4 serum concentration in both patients and controls. Patients with less than four total copies of C4 genes transplanted with a deceased donor kidney experienced a superior 5-year graft survival (hazard ratio 0.46, 95% confidence interval: 0.25-0.84). No significant association...... was observed in patients transplanted with a living donor. Thus, low C4 copy numbers are associated with increased kidney graft survival in patients receiving a kidney from a deceased donor. Hence, the degree of ischemia may influence the clinical impact of complement....

  16. Expression of C4.4A in precursor lesions of pulmonary adenocarcinoma and squamous cell carcinoma

    DEFF Research Database (Denmark)

    Jacobsen, Benedikte; Santoni-Rugiu, Eric; Illemann, Martin

    2012-01-01

    The protein C4.4A, a structural homologue of the urokinase-type plasminogen activator receptor, is a potential new biomarker in non-small cell lung cancer, with high levels of expression recently shown to correlate to poor survival of adenocarcinoma patients. In this study, C4.4A immunoreactivity...... in precursor lesions of lung squamous cell carcinoma and adenocarcinoma was investigated by stainings with a specific anti-C4.4A antibody. In the transformation from normal bronchial epithelium to squamous cell carcinoma, C4.4A was weakly expressed in basal cell hyperplasia but dramatically increased...... finding that C4.4A expression levels do not provide prognostic information on the survival of squamous cell carcinoma patients. In the progression from normal alveolar epithelium to peripheral adenocarcinoma, we observed an unexpected, distinct cytoplasmic staining for C4.4A in a fraction of atypical...

  17. Interactive data based on Apriori - AHP - C4.5 results assessment method

    Science.gov (United States)

    Zhao, Quan; Zhang, Li

    2017-05-01

    AHP method for weight calculation method, will introduce the subjective concept of "experts, supposed steps", for the objective result has certain uncertainty, causes the classroom interaction data attribute weights proportion difference is not big, the whole class achievement trend of convergence, introduce the concept of Apriori-AHP. C4.5 is used to calculate the weight of attribute column, and then using the Apriori-AHP algorithm calculate attribute weights, attribute importance weights on judgment performance indicators table overall consideration, with the weight of index table of gifted student achievement, make the class performance trends to fluctuate, have tended to be "standard" real results for teacher reference.

  18. Integrating autonomous distributed control into a human-centric C4ISR environment

    Science.gov (United States)

    Straub, Jeremy

    2017-05-01

    This paper considers incorporating autonomy into human-centric Command, Control, Communications, Computers, Intelligence, Surveillance and Reconnaissance (C4ISR) environments. Specifically, it focuses on identifying ways that current autonomy technologies can augment human control and the challenges presented by additive autonomy. Three approaches to this challenge are considered, stemming from prior work in two converging areas. In the first, the problem is approached as augmenting what humans currently do with automation. In the alternate approach, the problem is approached as treating humans as actors within a cyber-physical system-of-systems (stemming from robotic distributed computing). A third approach, combines elements of both of the aforementioned.

  19. Crystal structure of a four-stranded intercalated DNA: d(C4)

    Science.gov (United States)

    Chen, L.; Cai, L.; Zhang, X.; Rich, A.

    1994-01-01

    The crystal structure of d(C4) solved at 2.3-A resolution reveals a four-stranded molecule composed of two interdigitated or intercalated duplexes. The duplexes are held together by hemiprotonated cytosine-cytosine base pairs and are parallel stranded, but the two duplexes point in opposite directions. The molecule has a slow right-handed twist of 12.4 degrees between covalently linked cytosine base pairs, and the base stacking distance is 3.1 A. This is in general agreement with the NMR studies. A biological role for DNA in this conformation is suggested.

  20. Crystal structure features in a new compound C4B25Mg1.42

    Science.gov (United States)

    Konovalikhin, S. V.; Ponomarev, V. I.

    2015-09-01

    The composition of C4B25Mg1.42 crystal obtained by self-propagating high-temperature synthesis was determined using X-ray diffraction. This is the first crystalline structure where all boron atoms in the В12 icosahedron occupy crystallographically independent positions; this circumstance allowed us to analyze the effect of substituents on bond lengths in the icosahedron. The crystal structure features, including the channels filled with disordered Mg atoms and the spread of В—В endo- and exo-bond lengths in the icosahedra, are described. A crystallochemical analysis of pair bonds has been performed for the first time.

  1. Identification and sequence analysis of the Rhizobium meliloti dctA gene encoding the C4-dicarboxylate carrier.

    OpenAIRE

    Engelke, T.; Jording, D; Kapp, D.; Pühler, A

    1989-01-01

    Transposon Tn5-induced C4-dicarboxylate transport mutants of Rhizobium meliloti 2011 which could be complemented by cosmid pRmSC121 were subdivided into two classes. Class I mutants (RMS37 and RMS938) were defective in symbiotic C4-dicarboxylate transport and in nitrogen fixation. They were mutated in the structural gene dctA, which codes for the C4-dicarboxylate carrier. Class II mutants (RMS11, RMS16, RMS17, RMS24, and RMS31) expressed reduced activity in symbiotic C4-dicarboxylate transpor...

  2. THRESHOLD STUDIES ON TNT, COMPOSITION B, C-4, AND ANFO EXPLOSIVES USING THE STEVEN IMPACT TEST

    Energy Technology Data Exchange (ETDEWEB)

    Vandersall, K S; Switzer, L L; Garcia, F

    2006-06-20

    Steven Impact Tests were performed at low velocity on the explosives TNT (trinitrotolulene), Composition B (63% RDX, 36% TNT, and 1% wax by weight), C-4 (91% RDX, 5.3% Di (2-ethylhexyl) sebacate, 2.1% Polyisobutylene, and 1.6% motor oil by weight) and ANFO (94% ammonium Nitrate with 6% Fuel Oil) in attempts to obtain a threshold for reaction. A 76 mm helium driven gas gun was used to accelerate the Steven Test projectiles up to approximately 200 m/s in attempts to react (ignite) the explosive samples. Blast overpressure gauges, acoustic microphones, standard video and high-speed photography were used to characterize the level of any high explosive reaction violence. No bulk reactions were observed in the TNT, Composition B, C-4 or ANFO explosive samples impacted up to velocities in the range of 190-200 m/s. This work will outline the experimental details and discuss the lack of reaction when compared to the reaction thresholds of other common explosives. These results will also be compared to that of the Susan Test and reaction thresholds observed in the common small-scale safety tests such as the drop hammer and friction tests in hopes of drawing a correlation.

  3. Electron attachment, ionization and drift in c-C4F8

    Science.gov (United States)

    de Urquijo, J.; Basurto, E.

    2001-05-01

    The pulsed Townsend method has been used to measure the drift velocity ve and the density-normalized effective ionization coefficient (α-η)/N, (α and η are the ionization and attachment coefficients, respectively) in c-C4F8 over the density-normalized electric field strength E/N, 12 Td≤E/N≤43 Td and 330 Td≤E/N≤600 Td (1 Td = 10-17 V cm2), at pressures between 1 and 7.5 Torr (1 Torr = 133.3 Pa). For 12 Td≤E/N≤43 Td, the above parameters were found to be pressure independent, while for the range 330 Td≤E/N≤600 Td an inverse dependence of the above coefficients was found for gas pressures less than 2 Torr. Such dependence is believed to be due to the autodetachment of the originally formed, unstable parent negative ion c-C4F8-*. At low E/N, no previous data for ve or (α-η)/N were found for comparison with the present data. A critical field strength of E/Ncrit = 439.5 Td, for which α = η, was found to be in good agreement with previous data.

  4. Prediksi Ketepatan Waktu Kelulusan Dengan Algoritma Data Mining C4.5

    Directory of Open Access Journals (Sweden)

    Indah Puji Astuti

    2017-11-01

    Full Text Available The student is one of entities in University or Higher Education. The student has a variety of data, such as self-identity information such as address, type of school, work of parents, type of class, etc. In fact many students whose graduation rate is different, on time and not on time. The number of students who graduate is not on time will be a problem not only for university but also for faculty. The number of students graduating each year is one of points of assessment when faculty or study program submits accreditation. C4.5 Algorithm is one of classification algorithm with decision trees. In this study conducted an analysis of student data Engineering Studies Program University of Muhammadiyah Ponorogo 2012/2013. The decision trees in this case is useful for exploring student data, finding the hidden relationship between a number of candidate input attributes with a target attribute. The input attribute consist of, the type of school, address, work of parent, and type of class. The output attribute to classify is status, which consists of "on time" and "not on time". The results from this analysis shown that in this case the C4.5 algorithm can predict with an accuracy value only 82%.

  5. On C4H versus vibrationally excited CO in IRC + 10216

    Science.gov (United States)

    Cummins, S. E.; Morris, M.; Thaddeus, P.

    1980-01-01

    The identification of the 114,221-MHz line in the spectrum of the evolved carbon star IRC +10216 with a blend of the rotational transition of C4H and the first rotational transition of vibrationally excited CO is investigated. A spectrum of the source was obtained using an 11-m telescope in the range covering the N = 12 to 11 and 11 to 10 spin-doublet rotational transitions of C4H. Two peaks of equal intensity and width are found in each band, suggesting a spin rotation constant of 1.06 for the 12 to 11 doublet and 1.09 for the 11 to 10 doublet, and excluding the possibility that vibrationally excited CO made any contribution to the 12 to 11 doublet. An additional survey of the regions from 103.8 to 107.5 and 113.3 to 117.0 GHz has revealed no new lines stronger than 0.1 K in the spectrum of IRC +10216.

  6. A C4-oxidizing lytic polysaccharide monooxygenase cleaving both cellulose and cello-oligosaccharides.

    Science.gov (United States)

    Isaksen, Trine; Westereng, Bjørge; Aachmann, Finn L; Agger, Jane W; Kracher, Daniel; Kittl, Roman; Ludwig, Roland; Haltrich, Dietmar; Eijsink, Vincent G H; Horn, Svein J

    2014-01-31

    Lignocellulosic biomass is a renewable resource that significantly can substitute fossil resources for the production of fuels, chemicals, and materials. Efficient saccharification of this biomass to fermentable sugars will be a key technology in future biorefineries. Traditionally, saccharification was thought to be accomplished by mixtures of hydrolytic enzymes. However, recently it has been shown that lytic polysaccharide monooxygenases (LPMOs) contribute to this process by catalyzing oxidative cleavage of insoluble polysaccharides utilizing a mechanism involving molecular oxygen and an electron donor. These enzymes thus represent novel tools for the saccharification of plant biomass. Most characterized LPMOs, including all reported bacterial LPMOs, form aldonic acids, i.e., products oxidized in the C1 position of the terminal sugar. Oxidation at other positions has been observed, and there has been some debate concerning the nature of this position (C4 or C6). In this study, we have characterized an LPMO from Neurospora crassa (NcLPMO9C; also known as NCU02916 and NcGH61-3). Remarkably, and in contrast to all previously characterized LPMOs, which are active only on polysaccharides, NcLPMO9C is able to cleave soluble cello-oligosaccharides as short as a tetramer, a property that allowed detailed product analysis. Using mass spectrometry and NMR, we show that the cello-oligosaccharide products released by this enzyme contain a C4 gemdiol/keto group at the nonreducing end.

  7. Dimer rotation on the carbon-induced Si(001)-c(4×4) structure

    Science.gov (United States)

    Peng, G. W.; Sun, Y. Y.; Huan, A. C. H.; Feng, Y. P.

    2006-09-01

    We present first-principles results identifying the reaction pathways for Si dimer rotations on the carbon-induced Si(001)-c(4×4) surface. The nudged elastic band calculations show that the recently proposed rotated dimer model [Phys. Rev. Lett. 94, 076102 (2005)] can be obtained from the refined missing dimer model by dimer rotation with small energy barriers. It is found that the energy barrier is sensitive to the rotation directions of Si dimers. The energy barrier along the minimum energy path (MEP) is 0.82eV . Three stable configurations are identified along the MEP, one of which with a single rotated dimer is more stable than all existing models and its energy is lower than that of the rotated dimer model, the previously most stable structure, by 0.25eV per c(4×4) cell. The stabilization mechanism of the new stable structure is analyzed. We propose a possible method to search for new stable structures based on the existing models by mapping out the reaction paths in the phase configuration.

  8. C4BPB/C4BPA is a new susceptibility locus for venous thrombosis with unknown protein S-independent mechanism: results from genome-wide association and gene expression analyses followed by case-control studies.

    Science.gov (United States)

    Buil, Alfonso; Trégouët, David-Alexandre; Souto, Juan Carlos; Saut, Noémie; Germain, Marine; Rotival, Maxime; Tiret, Laurence; Cambien, Françcois; Lathrop, Mark; Zeller, Tanja; Alessi, Marie-Christine; Rodriguez de Cordoba, Santiago; Münzel, Thomas; Wild, Philipp; Fontcuberta, Jordi; Gagnon, France; Emmerich, Joseph; Almasy, Laura; Blankenberg, Stefan; Soria, José-Manuel; Morange, Pierre-Emmanuel

    2010-06-10

    Through its binding with protein S (PS), a key element of the coagulation/fibrinolysis cascade, the C4b-binding protein (C4BP) has been hypothesized to be involved in the susceptibility to venous thrombosis (VT). To identify genetic factors that may influence the plasma levels of the 3 C4BP existing isoforms, alpha(7)beta(1), alpha(6)beta(1), and alpha(7)beta(0), we conducted a genome-wide association study by analyzing 283 437 single nucleotide polymorphisms (SNPs) in the Genetic Analysis of Idiopathic Thrombophilia (GAIT) study composed of 352 persons. Three SNPs at the C4BPB/C4BPA locus were found genome-wide significantly associated with alpha(7)beta(0) levels. One of these SNPs was further found to explain approximately 11% of the variability of mRNA C4BPA expression in the Gutenberg Heart Study composed of 1490 persons, with no effect on C4BPB mRNA expression. The allele associated with increased alpha(7)beta(0) plasma levels and increased C4BPA expression was further found associated with increased risk of VT (odds ratio [OR] = 1.24 [1.03-1.53]) in 2 independent case-control studies (MARseille THrombosis Association study [MARTHA] and FActeurs de RIsque et de récidives de la maladie thromboembolique VEineuse [FARIVE]) gathering 1706 cases and 1379 controls. This SNP was not associated with free PS or total PS. In conclusion, we observed strong evidence that the C4BPB/C4BPA locus is a new susceptibility locus for VT through a PS-independent mechanism that remains to be elucidated.

  9. Complement system proteins which interact with C3b or C4b A superfamily of structurally related proteins

    DEFF Research Database (Denmark)

    Reid, K B M; Bentley, D R; Campbell, R D

    1986-01-01

    Recent cDNA sequencing data has allowed the prediction of the entire amino acid sequences of complement components factor B and C2, the complement control proteins factor H and C4b-binding protein and a partial sequence for the Cab/C4b receptor CR1. These proteins all contain internal repeating u...

  10. The differences between NAD-ME and NADP-ME subtypes of C4 photosynthesis: more than decarboxylating enzymes

    Directory of Open Access Journals (Sweden)

    Xiaolan Rao

    2016-10-01

    Full Text Available As an adaptation to changing climatic conditions that caused high rates of photorespiration, C4 plants have evolved to display higher photosynthetic efficiency than C3 plants under elevated temperature, high light intensities and drought. The C4 plants independently evolved more than 60 times in 19 families of angiosperms to establish similar but not uniform C4 mechanisms to concentrate CO2 around the carboxylating enzyme Rubisco. C4 photosynthesis is divided into at least two basic biochemical subtypes based on the primary decarboxylating enzymes, NAD-dependent malic enzyme (NAD-ME and NADP-dependent malic enzyme (NADP-ME. The multiple polygenetic origins of these subtypes raise questions about the association of C4 variation between biochemical subtypes and diverse lineages. This review addresses the differences in evolutionary scenario, leaf anatomy, and especially C4 metabolic flow, C4 transporters and cell-specific function deduced from recently reported cell-specific transcriptomic, proteomic and metabolic analyses of NAD-ME and NADP-ME subtypes. Current omic analysis has revealed the extent to which component abundances differ between the two biochemical subtypes, leading to a better understanding of C4 photosynthetic mechanisms in NAD-ME and NADP-ME subtypes.

  11. Synergistic inhibition of the intrinsic factor X activation by protein S and C4b-binding protein

    NARCIS (Netherlands)

    Koppelman, S.J.

    1995-01-01

    The complement protein C4b-binding protein plays an important role in the regulation of the protein C anticoagulant pathway. C4b-binding protein can bind to protein S, thereby inhibiting the cofactor activity of protein S for activated protein C. In this report, we describe a new role for

  12. Evidence that inducible C-4-type photosynthesis is a chloroplastic CO2-concentrating mechanism in Hydrilla, a submersed monocot

    NARCIS (Netherlands)

    Reiskind, JB; Madsen, TV; VanGinkel, LC; Bowes, G

    Hydrilla verticillata (L.f.) Royle exhibits an inducible C-4- type photosynthetic cycle, but lacks Kranz anatomy. Leaves in the C-4-type state (but not C-3-type) contained up to 5-fold higher internal dissolved inorganic carbon (DIG) concentrations than the medium, indicating that they possessed a

  13. Elements Required for an Efficient NADP-Malic Enzyme Type C4 Photosynthesis1[C][W][OPEN

    Science.gov (United States)

    Wang, Yu; Long, Stephen P.; Zhu, Xin-Guang

    2014-01-01

    C4 photosynthesis has higher light, nitrogen, and water use efficiencies than C3 photosynthesis. Although the basic anatomical, cellular, and biochemical features of C4 photosynthesis are well understood, the quantitative significance of each element of C4 photosynthesis to the high photosynthetic efficiency are not well defined. Here, we addressed this question by developing and using a systems model of C4 photosynthesis, which includes not only the Calvin-Benson cycle, starch synthesis, sucrose synthesis, C4 shuttle, and CO2 leakage, but also photorespiration and metabolite transport between the bundle sheath cells and mesophyll cells. The model effectively simulated the CO2 uptake rates, and the changes of metabolite concentrations under varied CO2 and light levels. Analyses show that triose phosphate transport and CO2 leakage can help maintain a high photosynthetic rate by balancing ATP and NADPH amounts in bundle sheath cells and mesophyll cells. Finally, we used the model to define the optimal enzyme properties and a blueprint for C4 engineering. As such, this model provides a theoretical framework for guiding C4 engineering and studying C4 photosynthesis in general. PMID:24521879

  14. Gene and genome duplications and the origin fo C4 photosysnthesis: Birth of a trait in the Cleomaceae

    NARCIS (Netherlands)

    Bergh, van den E.; Kulahoglu, C.; Brautigam, A.; Hibberd, J.M.; Weber, A.P.M.; Zhu, X.G.; Schranz, M.E.

    2014-01-01

    C4 photosynthesis is a trait that has evolved in 66 independent plant lineages and increases the efficiency of carbon fixation. The shift from C3 to C4 photosynthesis requires substantial changes to genes and gene functions effecting phenotypic, physiological and enzymatic changes. We investigate

  15. Expression of C4.4A in an in Vitro Human Tissue-Engineered Skin Model

    DEFF Research Database (Denmark)

    Jacobsen, Benedikte; Larouche, Danielle; Rochette-Drouin, Olivier

    2017-01-01

    , the biological function of C4.4A remains unknown. To enable further studies, we evaluated the expression of C4.4A in monolayer cultures of normal human keratinocytes and in tissue-engineered skin substitutes (TESs) produced by the self-assembly approach, which allow the formation of a fully differentiated...

  16. The role of C3 and C4 grasses to interannual variability in remotely sensed ecosystem performance over the US Great Plains

    Science.gov (United States)

    Ricotta, C.; Reed, Bradley C.; Tieszen, Larry L.

    2003-01-01

    Time integrated normalized difference vegetation index (ΣNDVI) derived from National Oceanic and Atmospheric Administration (NOAA) Advanced Very High Resolution Radiometer (AVHRR) multi-temporal imagery over a 10-year period (1989–1998) was used as a surrogate for primary production to investigate the impact of interannual climate variability on grassland performance for central and northern US Great Plains. First, the contribution of C3 and C4 species abundance to the major grassland ecosystems of the US Great Plains is described. Next, the relation between mean ΣNDVI and the ΣNDVI coefficient of variation (CV ΣNDVI) used as a proxy for interannual climate variability is analysed. Results suggest that the differences in the long-term climatic control over ecosystem performance approximately coincide with changes between C3- and C4-dominant grassland classes. Variation in remotely sensed net primary production over time is higher for the southern and western plains grasslands (primarily C4 grasslands), whereas the C3-dominated classes in the northern and eastern portion of the US Great Plains, generally show lower CV ΣNDVI values.

  17. In silico analysis of decomposed reflectances of C3 and C4 plants aiming at the effective assessment of crop needs

    Science.gov (United States)

    Baranoski, Gladimir V. G.; Van Leeuwen, Spencer; Chen, Tenn F.

    2017-04-01

    By separating the surface and subsurface components of foliar hyperspectral signatures using polarization optics, it is possible to enhance the remote discrimination of different plant species and optimize the assessment of different factors associated with their health status. These initiatives, in turn, can lead to higher crop yield and lower environmental impact. It is important to consider, however, that the main varieties of crops, represented by C3 (e.g., soy) and C4 (e.g., maize) plants, have markedly distinct morphological characteristics. Accordingly, the influence of these characteristics on their interactions with impinging light may affect the selection of optimal probe wavelengths for specific applications making use of combined hyperspectral and polarization measurements. In this paper, we compare the sensitivity of the total (including surface and subsurface components) and subsurface reflectance responses of C3 and C4 plants to different spectral and geometrical light incidence conditions. This investigation is supported by measured biophysical data and predictive light transport simulations. The results of our comparisons indicate that the total and subsurface reflectance responses of C3 and C4 plants depict well-defined patterns of sensitivity for varying illumination conditions. We believe that these patterns should be considered in the design of high-fidelity crop discrimination and monitoring procedures.

  18. Atmospheric CO2enrichment effect on the Cu-tolerance of the C4cordgrass Spartina densiflora.

    Science.gov (United States)

    Pérez-Romero, Jesús Alberto; Idaszkin, Yanina Lorena; Duarte, Bernardo; Baeta, Alexandra; Marques, João Carlos; Redondo-Gómez, Susana; Caçador, Isabel; Mateos-Naranjo, Enrique

    2018-01-01

    A glasshouse experiment was designed to investigate the effect of the co-occurrence of 400 and 700ppm CO 2 at 0, 15 and 45mM Cu on the Cu-tolerance of C 4 cordgrass species Spartina densiflora, by measuring growth, gas exchange, efficiency of PSII, pigments profiles, antioxidative enzyme activities and nutritional balance. Our results revealed that the rising atmospheric CO 2 mitigated growth reduction imposed by Cu in plants grown at 45mM Cu, leading to leaf Cu concentration bellow than 270mgKg -1 Cu, caused by an evident dilution effect. On the other hand, non-CO 2 enrichment plants showed leaf Cu concentration values up to 737.5mgKg -1 Cu. Furthermore, improved growth was associated with higher net photosynthetic rate (A N ). The beneficial effect of rising CO 2 on photosynthetic apparatus seems to be associated with a reduction of stomatal limitation imposed by Cu excess, which allowed these plants to maintain greater i WUE values. Also, plants grown at 45mM Cu and 700ppm CO 2 , showed higher ETR values and lower energy dissipation, which could be linked with an induction of Rubisco carboxylation and supported by the recorded amelioration of N imbalance. Furthermore, higher ETR values under CO 2 enrichment could lead to an additional consumption of reducing equivalents. Idea that was reflected in the lower values of ETR max /A N ratio, malondialdehyde (MDA) and ascorbate peroxidase (APx), guaiacol peroxidase (GPx) and superoxide dismutase (SOD) activities under Cu excess, which could indicate a lower production of ROS species under elevated CO 2 concentration, due to a better use of absorbed energy. Copyright © 2017 Elsevier GmbH. All rights reserved.

  19. Variation in chilling tolerance for photosynthesis and leaf extension growth among genotypes related to the C-4 grass Miscanthus xgiganteus

    Energy Technology Data Exchange (ETDEWEB)

    Glowacka, K; Adhikari, S; Peng, JH; Gifford, J; Juvik, JA; Long, SP; Sacks, EJ

    2014-09-08

    The goal of this study was to identify cold-tolerant genotypes within two species of Miscanthus related to the exceptionally chilling-tolerant C-4 biomass crop accession: M. xgiganteus 'Illinois' (Mxg) as well as in other Mxg genotypes. The ratio of leaf elongation at 10 degrees C/5 degrees C to that at 25 degrees C/25 degrees C was used to identify initially the 13 most promising Miscanthus genotypes out of 51 studied. Net leaf CO2 uptake (A(sat)) and the maximum operating efficiency of photosystem II (Phi(PSII)) were measured in warm conditions (25 degrees C/20 degrees C), and then during and following a chilling treatment of 10 degrees C/5 degrees C for 11 d. Accessions of M. sacchariflorus (Msa) showed the smallest decline in leaf elongation on transfer to chilling conditions and did not differ significantly from Mxg, indicating greater chilling tolerance than diploid M. sinensis (Msi). Msa also showed the smallest reductions in A(sat) and Phi(PSII), and greater chilling-tolerant photosynthesis than Msi, and three other forms of Mxg, including new triploid accessions and a hexaploid Mxg 'Illinois'. Tetraploid Msa 'PF30153' collected in Gifu Prefecture in Honshu, Japan did not differ significantly from Mxg 'Illinois' in leaf elongation and photosynthesis at low temperature, but was significantly superior to all other forms of Mxg tested. The results suggested that the exceptional chilling tolerance of Mxg 'Illinois' cannot be explained simply by the hybrid vigour of this intraspecific allotriploid. Selection of chilling-tolerant accessions from both of Mxg's parental species, Msi and Msa, would be advisable for breeding new highly chilling-tolerant Mxg genotypes.

  20. Southeast Atlantic upwelling intensity changes influencing late Miocene C4 plant expansion?

    Science.gov (United States)

    Rommerskirchen, F.; Condon, T.; Mollenhauer, G.; Schefuß, E.

    2009-04-01

    The Late Miocene epoch (about 15 to 5 Myrs BP) is characterised by fundamental changes in Earth's climate system: turnovers in marine and terrestrial biota, sea-level variability, changes in surface- und deep-water circulations, and increase in upwelling intensities along the coasts [1,2]. During the transition period the Antarctic ice sheets expanded and were permanently established, while additionally ice volumes began to fluctuate [1]. Plants acting with the C4 concentrating mechanism of CO2 fixation for photosynthesis expanded nearly simultaneous at different places in the world, whereas the global CO2 levels exhibit no corresponding change [1,3]. However, C4 plants are also known to have a competitive advantage in habitats of higher temperature, light and fire intensities as well as of limited water supply, compared to the almost ubiquitous C3 plants. This study tries to give insights to Miocene climatic conditions in Southwest Africa and how these conditions may be linked to the C4 plant expansion. We focused on data from a sediment core of the Ocean Drilling Program (Leg 175, ODP 1085A), which span about 10 Myrs of the late Miocene. The core is situated in the Cape basin at the south-western African continental margin in the upwelling zone of the Benguela coastal current. The current brings cold, nutrient-rich waters from South Atlantic and the Antarctic circumpolar current to the surface water along the coast of Southwest Africa. Miocene sea surface temperatures (SST) were reconstructed by two indices, tetraether index (TEX86) and an alkenone based index (U37K'). Both trends exhibit a shift to cooler temperatures from around 27 to 18˚ C, but are different in rate and timing. Especially by TEX86 reconstructed SSTs exhibit a similar trend as found for ice volume changes shown by the δ18O curve [4]. These findings may reflect an intensification of the Benguela upwelling current during the late Miocene, probably in association with the formation of West

  1. When did C4 Photosynthesis originate: New evidence from δ13C analysis of single grass-pollen grains

    Science.gov (United States)

    Urban, M. A.; Nelson, D. M.; Pearson, A.; Hu, F.

    2009-12-01

    C4 grasses account for >20% of global primary productivity and dominate tropical, subtropical, and warm-temperate grassland ecosystems. Thus it is vital to understand when and why C4 photosynthesis first evolved in the grass family (Poaceae). However, because of limitations of most proxies, the origin of C4 grasses remains ambiguous. Grass pollen is morphologically indistinct below the family level, making pollen analysis a crude instrument for studying C4-grass evolution. Previous studies have investigated the timing of C4 evolution using molecular tools and δ13C records from n-alkanes, ungulate teeth, and paleosols, but they yield disparate results. Molecular clocks suggest that C4 grasses first evolved between 27 and 36 Ma (million years before present), coincident with the Oligocene decline in pCO2 from >1000 to <500 ppm. In contrast, δ13C-based approaches do not detect the presence of C4 grasses until the middle Miocene, indicating that they were previously uncommon or absent on the landscape. To investigate when C4 photosynthesis first appeared in the grass family, we utilized Single Pollen Isotope Ratio AnaLysis (SPIRAL), a technique that reliably distinguishes C4 from C3 grass pollen via δ13C. We analyzed 837 single grains of grass pollen from eight lacustrine geological samples (~100 grains/sample) from France and Spain spanning the earliest Oligocene to middle Miocene. To distinguish C3/C4 ratios, we used an optimal threshold value of -19.2‰ adjusted for small (~1‰) temporal variations in atmospheric δ13C. Initial results provide unequivocal evidence of C4 grass pollen in all samples (24-57% C4 grass pollen ±9.2% on average) lending further credence to the molecular data, which posits that C4 grasses appeared as early as the Late Eocene, which is a plausible outcome when considering alternate schemes of dating phylogenetic trees. A C4 origin prior to pCO2 reaching its lowest levels of the Cenozoic at the Oligocene/Miocene boundary indicates that

  2. Conserved patterns hidden within group A Streptococcus M protein hypervariability recognize human C4b-binding protein.

    Science.gov (United States)

    Buffalo, Cosmo Z; Bahn-Suh, Adrian J; Hirakis, Sophia P; Biswas, Tapan; Amaro, Rommie E; Nizet, Victor; Ghosh, Partho

    2016-09-05

    No vaccine exists against group A Streptococcus (GAS), a leading cause of worldwide morbidity and mortality. A severe hurdle is the hypervariability of its major antigen, the M protein, with >200 different M types known. Neutralizing antibodies typically recognize M protein hypervariable regions (HVRs) and confer narrow protection. In stark contrast, human C4b-binding protein (C4BP), which is recruited to the GAS surface to block phagocytic killing, interacts with a remarkably large number of M protein HVRs (apparently ∼90%). Such broad recognition is rare, and we discovered a unique mechanism for this through the structure determination of four sequence-diverse M proteins in complexes with C4BP. The structures revealed a uniform and tolerant 'reading head' in C4BP, which detected conserved sequence patterns hidden within hypervariability. Our results open up possibilities for rational therapies that target the M-C4BP interaction, and also inform a path towards vaccine design.

  3. Conserved patterns hidden within group A Streptococcus M protein hypervariability recognize human C4b-binding protein

    Energy Technology Data Exchange (ETDEWEB)

    Buffalo, Cosmo Z.; Bahn-Suh, Adrian J.; Hirakis, Sophia P.; Biswas, Tapan; Amaro, Rommie E.; Nizet, Victor; Ghosh, Partho

    2016-09-05

    No vaccine exists against group A Streptococcus (GAS), a leading cause of worldwide morbidity and mortality. A severe hurdle is the hypervariability of its major antigen, the M protein, with >200 different M types known. Neutralizing antibodies typically recognize M protein hypervariable regions (HVRs) and confer narrow protection. In stark contrast, human C4b-binding protein (C4BP), which is recruited to the GAS surface to block phagocytic killing, interacts with a remarkably large number of M protein HVRs (apparently ~90%). Such broad recognition is rare, and we discovered a unique mechanism for this through the structure determination of four sequence-diverse M proteins in complexes with C4BP. The structures revealed a uniform and tolerant ‘reading head’ in C4BP, which detected conserved sequence patterns hidden within hypervariability. Our results open up possibilities for rational therapies that target the M–C4BP interaction, and also inform a path towards vaccine design.

  4. Yield responses of wild C3and C4crop progenitors to subambient CO2: a test for the role of CO2limitation in the origin of agriculture.

    Science.gov (United States)

    Cunniff, Jennifer; Jones, Glynis; Charles, Michael; Osborne, Colin P

    2017-01-01

    Limitation of plant productivity by the low partial pressure of atmospheric CO 2 (C a ) experienced during the last glacial period is hypothesized to have been an important constraint on the origins of agriculture. In support of this hypothesis, previous work has shown that glacial C a limits vegetative growth in the wild progenitors of both C 3 and C 4 founder crops. Here, we present data showing that glacial C a also reduces grain yield in both crop types. We grew four wild progenitors of C 3 (einkorn wheat and barley) and C 4 crops (foxtail and broomcorn millets) at glacial and postglacial C a , measuring grain yield and the morphological and physiological components contributing to these yield changes. The C 3 species showed a significant increase in unthreshed grain yield of ~50% with the glacial to postglacial increase in C a , which matched the stimulation of photosynthesis, suggesting that increases in photosynthesis are directly translated into yield at subambient levels of C a . Increased yield was controlled by a higher rate of tillering, leading to a larger number of tillers bearing fertile spikes, and increases in seed number and size. The C 4 species showed smaller, but significant, increases in grain yield of 10-15%, arising from larger seed numbers and sizes. Photosynthesis was enhanced by C a in only one C 4 species and the effect diminished during development, suggesting that an indirect mechanism mediated by plant water relations could also be playing a role in the yield increase. Interestingly, the C 4 species at glacial C a showed some evidence that photosynthetic capacity was upregulated to enhance carbon capture. Development under glacial C a also impacted negatively on the subsequent germination and viability of seeds. These results suggest that the grain production of both C 3 and C 4 crop progenitors was limited by the atmospheric conditions of the last glacial period, with important implications for the origins of agriculture. © 2016

  5. Allometric Models for Predicting Aboveground Biomass and Carbon Stock of Tropical Perennial C4 Grasses in Hawaii

    Directory of Open Access Journals (Sweden)

    Adel H. Youkhana

    2017-05-01

    Full Text Available Biomass is a promising renewable energy option that provides a more environmentally sustainable alternative to fossil resources by reducing the net flux of greenhouse gasses to the atmosphere. Yet, allometric models that allow the prediction of aboveground biomass (AGB, biomass carbon (C stock non-destructively have not yet been developed for tropical perennial C4 grasses currently under consideration as potential bioenergy feedstock in Hawaii and other subtropical and tropical locations. The objectives of this study were to develop optimal allometric relationships and site-specific models to predict AGB, biomass C stock of napiergrass, energycane, and sugarcane under cultivation practices for renewable energy and validate these site-specific models against independent data sets generated from sites with widely different environments. Several allometric models were developed for each species from data at a low elevation field on the island of Maui, Hawaii. A simple power model with stalk diameter (D was best related to AGB and biomass C stock for napiergrass, energycane, and sugarcane, (R2 = 0.98, 0.96, and 0.97, respectively. The models were then tested against data collected from independent fields across an environmental gradient. For all crops, the models over-predicted AGB in plants with lower stalk D, but AGB was under-predicted in plants with higher stalk D. The models using stalk D were better for biomass prediction compared to dewlap H (Height from the base cut to most recently exposed leaf dewlap models, which showed weak validation performance. Although stalk D model performed better, however, the mean square error (MSE-systematic was ranged from 23 to 43 % of MSE for all crops. A strong relationship between model coefficient and rainfall was existed, although these were irrigated systems; suggesting a simple site-specific coefficient modulator for rainfall to reduce systematic errors in water-limited areas. These allometric equations

  6. Sources and Formation Processes of Short-Chain Saturated Diacids (C2–C4 in Inhalable Particles (PM10 from Huangshi City, Central China

    Directory of Open Access Journals (Sweden)

    Hongxia Liu

    2017-11-01

    Full Text Available PM10 samples were collected from Huangshi (HS city, Central China during April 2012 to March 2013, and were analyzed for short-chain saturated dicarboxylic acids (diacids using a capillary gas chromatograph (GC. We found that oxalic acid (C2, 318 ± 104 ng·m−3 was the most abundant diacid species, followed by malonic acid (C3, 25.4 ± 9.11 ng·m−3 and succinic acid (C4, 2.09 ± 0.52 ng·m−3. The concentrations of C2 and C4 diacids were highest in winter, followed by summer and spring, and lowest in autumn. C3 diacid was decreased in the order of summer > winter > autumn > spring. Further, the seasonal variations of WSOC (water-soluble organic carbon- and OC (organic carbon-normalized diacid concentrations were similar to those of diacid concentrations, suggesting that both primary emission and secondary production are important sources for diacids in Huangshi (HS aerosols. Strong correlations were found among C2 diacid and the three ions SO42−, NO3−, and NH4+ in summer and winter, suggesting that the species could undergo a similar secondary oxidation processing. C2 had good correlation with K+ in summer and autumn, which indicates an enhanced contribution of combustion sources for C2 diacid. Moreover, according to the ratio of C2/K+, we can conclude that C2 diacid should be formed by a secondary reaction of biomass combustion in HS aerosols, especially in summer and autumn. The ratios of C2/C4 and C3/C4 were compared with those reported in other sites, and the results suggest that HS aerosols should be more photochemically aged than at other urban areas. Principal component analysis of diacids and selected water-soluble inorganic ions over four seasons suggests that HS aerosols are influenced not only from primary emission, but also from secondary reaction. According to the linear relation between C2 and C3 diacids, the results indicate that C2 diacid is formed from the oxidation of hydrocarbon compounds in spring, while it is from

  7. Classification of C3 and C4 Vegetation Types Using MODIS and ETM+ Blended High Spatio-Temporal Resolution Data

    Directory of Open Access Journals (Sweden)

    Xiaolong Liu

    2015-11-01

    Full Text Available The distribution of C3 and C4 vegetation plays an important role in the global carbon cycle and climate change. Knowledge of the distribution of C3 and C4 vegetation at a high spatial resolution over local or regional scales helps us to understand their ecological functions and climate dependencies. In this study, we classified C3 and C4 vegetation at a high resolution for spatially heterogeneous landscapes. First, we generated a high spatial and temporal land surface reflectance dataset by blending MODIS (Moderate Resolution Imaging Spectroradiometer and ETM+ (Enhanced Thematic Mapper Plus data. The blended data exhibited a high correlation (R2 = 0.88 with the satellite derived ETM+ data. The time-series NDVI (Normalized Difference Vegetation Index data were then generated using the blended high spatio-temporal resolution data to capture the phenological differences between the C3 and C4 vegetation. The time-series NDVI revealed that the C3 vegetation turns green earlier in spring than the C4 vegetation, and senesces later in autumn than the C4 vegetation. C4 vegetation has a higher NDVI value than the C3 vegetation during summer time. Based on the distinguished characteristics, the time-series NDVI was used to extract the C3 and C4 classification features. Five features were selected from the 18 classification features according to the ground investigation data, and subsequently used for the C3 and C4 classification. The overall accuracy of the C3 and C4 vegetation classification was 85.75% with a kappa of 0.725 in our study area.

  8. Yersinia enterocolitica serum resistance proteins YadA and ail bind the complement regulator C4b-binding protein.

    Directory of Open Access Journals (Sweden)

    Vesa Kirjavainen

    Full Text Available Many pathogens are equipped with factors providing resistance against the bactericidal action of complement. Yersinia enterocolitica, a Gram-negative enteric pathogen with invasive properties, efficiently resists the deleterious action of human complement. The major Y. enterocolitica serum resistance determinants include outer membrane proteins YadA and Ail. Lipopolysaccharide (LPS O-antigen (O-ag and outer core (OC do not contribute directly to complement resistance. The aim of this study was to analyze a possible mechanism whereby Y. enterocolitica could inhibit the antibody-mediated classical pathway of complement activation. We show that Y. enterocolitica serotypes O:3, O:8, and O:9 bind C4b-binding protein (C4bp, an inhibitor of both the classical and lectin pathways of complement. To identify the C4bp receptors on Y. enterocolitica serotype O:3 surface, a set of mutants expressing YadA, Ail, O-ag, and OC in different combinations was tested for the ability to bind C4bp. The studies showed that both YadA and Ail acted as C4bp receptors. Ail-mediated C4bp binding, however, was blocked by the O-ag and OC, and could be observed only with mutants lacking these LPS structures. C4bp bound to Y. enterocolitica was functionally active and participated in the factor I-mediated degradation of C4b. These findings show that Y. enterocolitica uses two proteins, YadA and Ail, to bind C4bp. Binding of C4bp could help Y. enterocolitica to evade complement-mediated clearance in the human host.

  9. Sequential unfolding of the two-domain protein Pseudomonas stutzeri cytochrome c(4)

    DEFF Research Database (Denmark)

    Andersen, Niels Højmark; Jensen, Thomas Jon; Nørgaard, Allan

    2002-01-01

    , and different spin states of the oxidised haem groups. We have studied unfolding of oxidised P. stutzeri cyt c(4) induced thermally and by chemical denaturants Horse heart cyt c was a reference molecule. Isothermal unfolding induced by guanidinium chloride and acid was followed by Soret. alpha/beta. and 701-nm...... chloride up to 0.4 M is present. This reflects different chemical action in chemical and thermal unfolding. Acid-induced unfolding kinetics was addressed by pH jumps using diode array stopped-flow techniques, Three kinetic phases in the 701 nm Fe-Met marker band. and four phases in the Soret and alpha/beta......F stutzeri cytochrome c. is a di-haem protein, composed of two globular domains each with His-Met coordinated haem. and a hydrogen bond network between the domains. The domain foldings are highly symmetric but with specific differences including structural differences of ligand coordination...

  10. Improved tissue culture conditions for the emerging C4 model Panicum hallii.

    Science.gov (United States)

    Grant, Joshua N; Burris, Jason N; Stewart, C Neal; Lenaghan, Scott C

    2017-04-27

    Panicum hallii Vasey (Hall's panicgrass) is a compact, perennial C4 grass in the family Poaceae, which has potential to enable bioenergy research for switchgrass (Panicum virgatum L.). Unlike P. hallii, switchgrass has a large genome, allopolyploidy, self-incompatibility, a long life cycle, and large stature-all suboptimal traits for rapid genetics research. Herein we improved tissue culture methodologies for two inbred P. hallii populations: FIL2 and HAL2, to enable further development of P. hallii as a model C4 plant. The optimal seed-derived callus induction medium was determined to be Murashige and Skoog (MS) medium supplemented with 40 mg L-1 L-cysteine, 300 mg L-1 L-proline, 3% sucrose, 1 g L-1 casein hydrolysate, 3 mg L-1 2,4-dichlorophenoxyacetic acid (2,4-D), and 45 μg L-1 6-benzylaminopurine (BAP), which resulted in callus induction of 51 ± 29% for FIL2 and 81 ± 19% for HAL2. The optimal inflorescence-derived callus induction was observed on MP medium (MS medium supplemented with 2 g L-1 L-proline, 3% maltose, 5 mg L-1 2,4-D, and 500 μg L-1 BAP), resulting in callus induction of 100 ± 0.0% for FIL2 and 84 ± 2.4% for HAL2. Shoot regeneration rates of 11.5 ± 0.8 shoots/gram for FIL2 and 11.3 ± 0.6 shoots/gram for HAL2 were achieved using seed-induced callus, whereas shoot regeneration rates of 26.2 ± 2.6 shoots/gram for FIL2 and 29.3 ± 3.6 shoots/gram for HAL2 were achieved from inflorescence-induced callus. Further, cell suspension cultures of P. hallii were established from seed-derived callus, providing faster generation of callus tissue compared with culture using solidified media (1.41-fold increase for FIL2 and 3.00-fold increase for HAL2). Aside from abbreviated tissue culture times from callus induction to plant regeneration for HAL2, we noted no apparent differences between FIL2 and HAL2 populations in tissue culture performance. For both populations, the cell suspension cultures

  11. Carbon and oxygen isotope working standards from C3 and C4 photosynthates.

    Science.gov (United States)

    Spangenberg, Jorge E

    2006-09-01

    A preparation of organic working standards for the online measurement of 13C/12C and 18O/16O ratios in biological material is presented. The organic working standards are simple and inexpensive C3 and C4 carbohydrates (sugars or cellulose) from distinct geographic origin, including white sugar, toilet and XEROX papers from Switzerland, maize from Ivory Coast, cane sugar from Brazil, papyrus from Egypt, and the core of the stem of a Cyperus papyrus plant from Kenya. These photosynthetic products were compared with International Atomic Energy standards CH-3 and CH-6 and other calibration materials. The presented working standards cover a 15% range of 13C/12C ratios and 9% for 18O/16O, with a precision10.

  12. High-resolution Moho model for Greenland from EIGEN-6C4 gravity data

    DEFF Research Database (Denmark)

    Steffen, Rebekka; Strykowski, Gabriel; Lund, Björn

    2017-01-01

    basins. We also correct for the effect on gravity due to the weight of the ice sheet and the accompanying deflection of the Earth's surface, which has not previously been taken into account in gravity studies of currently glaciated regions. Our final Moho depth model for Greenland has an associated......The crust–mantle boundary (the Moho) is a first order interface in the Earth and the depth to the Moho is therefore well studied in most regions. However, below regions which are covered by large ice sheets, such as Greenland and Antarctica, the Moho is only partly known and seismic data...... are difficult to obtain. Here, we take advantage of the global gravity model EIGEN-6C4, together with the Parker-Oldenburg algorithm, to estimate the depth to the Moho beneath Greenland and surroundings. The available free-air gravity data are corrected for the topographic effect and the effect of sedimentary...

  13. VHMPID RICH prototype using pressurized C4F8O radiator gas and VUV photon detector

    Science.gov (United States)

    Acconcia, T. V.; Agócs, A. G.; Barile, F.; Barnaföldi, G. G.; Bellwied, R.; Bencédi, G.; Bencze, G.; Berényi, D.; Boldizsár, L.; Chattopadhyay, S.; Chinellato, D. D.; Cindolo, F.; Cossyleon, K.; Das, D.; Das, K.; Das-Bose, L.; Dash, A. K.; D`Ambrosio, S.; De Cataldo, G.; De Pasquale, S.; Di Bari, D.; Di Mauro, A.; Futó, E.; Garcia-Solis, E.; Hamar, G.; Harton, A.; Iannone, G.; Jimenez, R. T.; Kim, D. W.; Kim, J. S.; Knospe, A.; Kovács, L.; Lévai, P.; Markert, C.; Martinengo, P.; Molnár, L.; Nappi, E.; Oláh, L.; Paić, G.; Pastore, C.; Patimo, G.; Patino, M. E.; Peskov, V.; Pinsky, L.; Piuz, F.; Pochybová, S.; Sgura, I.; Sinha, T.; Song, J.; Takahashi, J.; Timmins, A.; Van Beelen, J. B.; Varga, D.; Volpe, G.; Weber, M.; Xaplanteris, L.; Yi, J.; Yoo, I.-K.

    2014-12-01

    A small-size prototype of a new Ring Imaging Cherenkov (RICH) detector using for the first time pressurized C4F8O radiator gas and a photon detector consisting of MWPC equipped with a CsI photocathode has been built and tested at the PS accelerator at CERN. It contained all the functional elements of the detector proposed as Very High Momentum Particle Identification (VHMPID) upgrade for the ALICE experiment at LHC to provide charged hadron track-by-track identification in the momentum range starting from 5 potentially up to 25 GeV/c. In the paper the equipment and its elements are described and some characteristic test results are shown.

  14. C-4 Gem-Dimethylated Oleanes of Gymnema sylvestre and Their Pharmacological Activities

    Directory of Open Access Journals (Sweden)

    Giovanni Di Fabio

    2013-12-01

    Full Text Available Gymnema sylvestre R. Br., one of the most important medicinal plants of the Asclepiadaceae family, is a herb distributed throughout the World, predominantly in tropical countries. The plant, widely used for the treatment of diabetes and as a diuretic in Indian proprietary medicines, possesses beneficial digestive, anti-inflammatory, hypoglycemic and anti-helmentic effects. Furthermore, it is believed to be useful in the treatment of dyspepsia, constipation, jaundice, hemorrhoids, cardiopathy, asthma, bronchitis and leucoderma. A literature survey revealed that some other notable pharmacological activities of the plant such as anti-obesity, hypolipidemic, antimicrobial, free radical scavenging and anti-inflammatory properties have been proven too. This paper aims to summarize the chemical and pharmacological reports on a large group of C-4 gem-dimethylated pentacyclic triterpenoids from Gymnema sylvestre.

  15. C4-alkylthiols with activity against Moraxella catarrhalis and Mycobacterium tuberculosis.

    Science.gov (United States)

    Kostova, Maya B; Myers, Carey J; Beck, Tim N; Plotkin, Balbina J; Green, Jacalyn M; Boshoff, Helena I M; Barry, Clifton E; Deschamps, Jeffrey R; Konaklieva, Monika I

    2011-11-15

    Antimicrobial resistance represents a global threat to healthcare. The ability to adequately treat infectious diseases is increasingly under siege due to the emergence of drug-resistant microorganisms. New approaches to drug development are especially needed to target organisms that exhibit broad antibiotic resistance due to expression of β-lactamases which is the most common mechanism by which bacteria become resistant to β-lactam antibiotics. We designed and synthesized 20 novel monocyclic β-lactams with alkyl- and aryl-thio moieties at C4, and subsequently tested these for antibacterial activity. These compounds demonstrated intrinsic activity against serine β-lactamase producing Mycobacterium tuberculosis wild type strain (Mtb) and multiple (n=6) β-lactamase producing Moraxella catarrhalis clinical isolates. Copyright © 2011 Elsevier Ltd. All rights reserved.

  16. [The analysis of C4 and C5 olefins in cracking gasoline].

    Science.gov (United States)

    Zhang, Z; Yang, H; Wang, H

    1997-07-01

    The paper described the analytical method of butenes and pentenes in cracking gasoline with a boiling point range from initial to 210 degrees C. Beside the C3 (propane + protene) and n, i-C4 = (n-butene + i-butene) combine peaks, all C2-C5 components in the sample were separated on the OV-1 column. The proportion of the combined peaks was determined on the Al2O3 column. The quantitative results were calculated on the data determined from the above one-column analytical systems with a relative standard deviation ASTM D2427-87, the simple operation, easy application, good repetition and all component results were characteristic of the method.

  17. Optical spectroscopy study of c(4 x 2) Ge (001)-surfaces, covered with atomic Au wires

    Energy Technology Data Exchange (ETDEWEB)

    Bass, Utz; Meyer, Sebastian; Schaefer, Joerg; Geurts, Jean [Universitaet Wuerzburg, Physikalisches Institut, Am Hubland, 97074 Wuerzburg (Germany); Speiser, Eugen; Esser, Norbert [ISAS, Albert-Einstein-Strasse 9, 12489 Berlin (Germany)

    2011-07-01

    Novel quasi-1D systems like e.g. atomic gold chains on a c(4x2) reconstructed Ge(001)-surfaces enable the investigation of 1D-effects like the possible occurrence of the Luttinger- to Fermi liquid transition. As there is a crucial interplay of the lattice vibrations and the electrical and structural properties on such sensitive systems, phonon dynamics are in the focus of this work. The phonons were addressed by Raman spectroscopy and reveal a clear change from the Ge-oxide layer to the final surface with Au-nano wires. Thermally deoxidizing the Ge-surface under UHV leads to a distinct low-frequency vibration around 65cm-1. Its frequency range and its persistence after Gold deposition in the submonolayer range indicate that this signal is surface related. Additionally, the surface-induced anisotropy of the optical reflectance was complementary investigated by Reflectance-Anisotropy-Spectroscopy (RAS) and IR-ellipsometry.

  18. Production of C4 and C5 branched-chain alcohols by engineered Escherichia. coli.

    Science.gov (United States)

    Chen, Xiaoyan; Xu, Jingliang; Yang, Liu; Yuan, Zhenhong; Xiao, Shiyuan; Zhang, Yu; Liang, Cuiyi; He, Minchao; Guo, Ying

    2015-11-01

    Higher alcohols, longer chain alcohols, contain more than 3 carbon atoms, showed close energy advantages as gasoline, and were considered as the next generation substitution for chemical fuels. Higher alcohol biosynthesis by native microorganisms mainly needs gene expression of heterologous keto acid decarboxylase and alcohol dehydrogenases. In the present study, branched-chain α-keto acid decarboxylase gene from Lactococcus lactis subsp. lactis CICC 6246 (Kivd) and alcohol dehydrogenases gene from Zymomonas mobilis CICC 41465 (AdhB) were transformed into Escherichia coli for higher alcohol production. SDS-PAGE results showed these two proteins were expressed in the recombinant strains. The resulting strain was incubated in LB medium at 37 °C in Erlenmeyer flasks and much more 3-methyl-1-butanol (104 mg/L) than isobutanol (24 mg/L) was produced. However, in 5 g/L glucose-containing medium, the production of two alcohols was similar, 156 and 161 mg/L for C4 (isobutanol) and C5 (3-methyl-1-butanol) alcohol, respectively. Effects of fermentation factors including temperature, glucose content, and α-keto acid on alcohol production were also investigated. The increase of glucose content and the adding of α-keto acids facilitated the production of C4 and C5 alcohols. The enzyme activities of pure Kivd on α-ketoisovalerate and α-ketoisocaproate were 26.77 and 21.24 μmol min(-1) mg(-1), respectively. Due to its ability on decarboxylation of α-ketoisovalerate and α-ketoisocaproate, the recombinant E. coli strain showed potential application on isoamyl alcohol and isobutanol production.

  19. Larsen syndrome with C3-C4 spondyloptosis and atlantoaxial dislocation in an adult.

    Science.gov (United States)

    Roopesh Kumar, V R; Madhguiri, Venkatesh S; Sasidharan, Gopalakrishnan M; Gundamaneni, Sudheer Kumar; Yadav, Awdhesh Kumar

    2013-01-01

    This is a clinical case report with a review of relevant literature. To describe a case of Larsen syndrome with C3-C4 spondyloptosis and atlantoaxial dislocation in a middle-aged female patient and to discuss management strategies. Spondyloptosis of the cervical spine is relatively rare and is caused by trauma, destruction of the vertebral bodies by tumors, or tuberculosis. Such gross vertebral displacement is usually associated with significant neurological deficits. Larsen syndrome is characterized by multiple joint displacements and can, very rarely, be associated with nontraumatic spondyloptosis of the cervical vertebra. A single case report of C1-C2 joint laxity causing atlantoaxial dislocation in a patient with Larsen syndrome is available in literature. No reports of any patient (with Larsen syndrome or nonsyndromic) who had both cervical spondyloptosis and atlantoaxial dislocation are available in literature. A 36-year-old female presented with chronic neck pain, bilateral hand deformity, and mild spasticity involving all 4 limbs. Cervical radiograph, computed tomographic scan, and magnetic resonance image revealed C3-C4 spondyloptosis and atlantoaxial dislocation. A combined ventral decompression of subaxial spine and instrumentation from C2 to C5, followed by posterior C1-C2 distraction arthroplasty and lateral mass stabilization of the subaxial spine up to C6, was done. The cervical deformity was corrected, and the patient remains symptom free. Patients with spondyloptosis of the cervical spine can rarely present with chronic neck pain and minimal neurological deficits. An additional pathology, such as atlantoaxial dislocation, can add to the complexity. Circumferential stabilization and fusion would be required in such cases to achieve a good outcome. Larsen syndrome is a rare cause of nontraumatic cervical displacements.

  20. Elevated levels of the complement activation product C4d in bronchial fluids for the diagnosis of lung cancer.

    Directory of Open Access Journals (Sweden)

    Daniel Ajona

    Full Text Available Molecular markers in bronchial fluids may contribute to the diagnosis of lung cancer. We previously observed a significant increase of C4d-containing complement degradation fragments in bronchoalveolar lavage (BAL supernatants from lung cancer patients in a cohort of 50 cases and 22 controls (CUN cohort. The present study was designed to determine the diagnostic performance of these complement fragments (hereinafter jointly referred as C4d in bronchial fluids. C4d levels were determined in BAL supernatants from two independent cohorts: the CU cohort (25 cases and 26 controls and the HUVR cohort (60 cases and 98 controls. A series of spontaneous sputum samples from 68 patients with lung cancer and 10 controls was also used (LCCCIO cohort. Total protein content, complement C4, complement C5a, and CYFRA 21-1 were also measured in all cohorts. C4d levels were significantly increased in BAL samples from lung cancer patients. The area under the ROC curve was 0.82 (95%CI = 0.71-0.94 and 0.67 (95%CI = 0.58-0.76 for the CU and HUVR cohorts, respectively. In addition, unlike the other markers, C4d levels in BAL samples were highly consistent across the CUN, CU and HUVR cohorts. Interestingly, C4d test markedly increased the sensitivity of bronchoscopy in the two cohorts in which cytological data were available (CUN and HUVR cohorts. Finally, in the LCCCIO cohort, C4d levels were higher in sputum supernatants from patients with lung cancer (area under the ROC curve: 0.7; 95%CI = 0.56-0.83. In conclusion, C4d is consistently elevated in bronchial fluids from lung cancer patients and may be used to improve the diagnosis of the disease.

  1. Starch Accumulation in the Bundle Sheaths of C3 Plants: A Possible Pre-Condition for C4 Photosynthesis.

    Science.gov (United States)

    Miyake, Hiroshi

    2016-05-01

    C4 plants have evolved >60 times from their C3 ancestors. C4 photosynthesis requires a set of closely co-ordinated anatomical and biochemical characteristics. However, it is now recognized that the evolution of C4 plants requires fewer changes than had ever been considered, because of the genetic, biochemical and anatomical pre-conditions of C3 ancestors that were recruited into C4 photosynthesis. Therefore, the pre-conditions in C3 plants are now being actively investigated to clarify the evolutionary trajectory from C3 to C4 plants and to engineer C4 traits efficiently into C3 crops. In the present mini review, the anatomical characteristics of C3 and C4 plants are briefly reviewed and the importance of the bundle sheath for the evolution of C4 photosynthesis is described. For example, while the bundle sheath of C3 rice plants accumulates large amounts of starch in the developing leaf blade and at the lamina joint of the mature leaf, the starch sheath function is also observed during leaf development in starch accumulator grasses regardless of photosynthetic type. The starch sheath function of C3 plants is therefore also implicated as a possible pre-condition for the evolution of C4 photosynthesis. The phylogenetic relationships between the types of storage carbohydrates and of photosynthesis need to be clarified in the future. © The Author 2016. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  2. Classification of C3 and C4 Vegetation Types Using MODIS and ETM+ Blended High Spatio-Temporal Resolution Data

    OpenAIRE

    Xiaolong Liu; Yanchen Bo; Jian Zhang; Yaqian He

    2015-01-01

    The distribution of C3 and C4 vegetation plays an important role in the global carbon cycle and climate change. Knowledge of the distribution of C3 and C4 vegetation at a high spatial resolution over local or regional scales helps us to understand their ecological functions and climate dependencies. In this study, we classified C3 and C4 vegetation at a high resolution for spatially heterogeneous landscapes. First, we generated a high spatial and temporal land surface reflectance dataset by b...

  3. Effects of radiation damping on photorecombination of C4 + ions for the KLL resonance

    Science.gov (United States)

    Li, Chuan-Ying; Wu, Yong; Qu, Yi-Zhi; Wang, Jian-Guo

    2016-10-01

    A numerical method based on Zabaydullin and Dubau's work [O. Zabaydullin and J. Dubau, J. Phys. B: At. Mol. Opt. Phys. 45, 115002 (2012), 10.1088/0953-4075/45/11/115002] has been developed to calculate the Cauchy principal value integral in scattering matrices and obtain photorecombination (PR) cross sections of low-lying resonances according to Davies and Seaton's theory [J. Phys. B 2, 757 (1969), 10.1088/0022-3700/2/7/304], in which radiation damping is included. The Dirac R -matrix method is employed to secure the dipole matrix. Using this method, PR cross sections of C4 + for the KLL resonance are acquired, and compared with available experimental measurements and other close-coupling theoretical results. It is shown that our damped cross sections reproduce the experimental data and are in agreement with other theoretical results. Meanwhile, radiation damping can reduce the PR cross section for the 1 s 2 p22P resonance (corresponding to two levels [(1s2p1 /2) 12 p3 /2] 1 /2 and [1s (2p3/22)2] 3 /2 by three orders of magnitude. The unresolved and underestimated resonances 1 s 2 p24P , 1 s 2 s 2 p 4P , and 1 s 2 p22P in the undamped Breit-Pauli R -matrix calculations [H. L. Zhang et al., J. Phys. B: At. Mol. Opt. Phys. 32, 1459 (1999), 10.1088/0953-4075/32/6/010] are corrected. Besides, dielectronic recombination cross sections of C4 + for the KLL resonance are also presented for comparison using the relativistic configuration-interaction (RCI) method implemented in flexible atomic code (fac), which show radiation damping has pronounced influences on 1 s 2 p22P due to much larger radiative rates compared with autoionization rates. Furthermore, radiative and autoionization rates for the intermediate states [(1s2p1 /2) 12 p3 /2] 1 /2 and [1s (2p3/22)2] 3 /2 of the He-like ions with 6 ≤Z ≤83 are calculated using fac, scaling laws of which are checked. Autoionization rates comply with the Zeff0 scaling law for Z ≥32 , which is caused by relativistic effects.

  4. Comparison of physiological and anatomical changes of C3 (Oryza sativa [L.]) and C4 (Echinochloa crusgalli [L.]) leaves in response to drought stress

    Science.gov (United States)

    Hamim, Hamim; Banon, Sri; Dorly, Dorly

    2016-01-01

    The experiment aimed to analyse the different response of C3 (Oryza sativa L.) and C4 (Echinochloa crusgalli L.) species to drought stress based on physiological and anatomical properties. Seeds of rice (Oryza sativa) and Echinochloa (Echinochloa crusgalli) were grown in 15 cm (D) pot for 6 weeks under well-watered conditions. After 6 weeks the plants were divided into two groups, (1) well-watered which were watered daily, and (2) drought stress which were withheld from watering for 6 days. After 6 days of drought, the plants were then re-watered to analyse plant recovery. During drought period, the plants were analysed for growth, leaf relative water content (RWC), photosynthesis, and leaf anatomy. Drought stress significantly reduced leaf RWC of both species, but the reduction was bigger in rice than in Echinochloa. The maximum efficiency of photosynthesis (Fv/Fm) was decrease significantly in response to drought stress by about 48.04% in rice, while it was only 34.40% in Echinochloa. Anatomical analysis showed drought treatment tended to reduce leaf thickness in the area of bulliform cell, major- as well as intervein and xylem diameter, more in Echinochloa than in rice, suggesting that the decrease of vein and xylem diameter is among the anatomical parameters that is important to overcome from drought stress in Echinochloa. The number of chloroplast in the mesophyll cell and bundle sheath cell (BSC) was different between these two species, where in Echinochloa chloroplast was found in both mesophyll as well as BSC, while in rice it was only found in mesophyll cell, confirmed that Echinochloa is a C4 and rice is a C3 species. Interestingly, in Echinochloa, the number of chloroplast was significantly increased due to drought stress in BSC, but not in mesophyll cell. The number of starch granules also dramatically increased in response to drought in the mesophyll cells of rice and Echinochloa, and in the bundle sheath cell of Echinochloa which indicate that C3

  5. Klasifikasi Nilai Kelayakan Calon Debitur Baru Menggunakan Decision Tree C4.5

    Directory of Open Access Journals (Sweden)

    Bambang Hermanto

    2017-01-01

    Full Text Available In an effort to improve the quality of customer service, especially in terms of feasibility assessment of borrowers due to the increasing number of new prospective borrowers loans financing the purchase of a motor vehicle, then the company needs a decision making tool allowing you to easily and quickly estimate Where the debtor is able to pay off the loans. This study discusses the process generates C4.5 decision tree algorithm and utilizing the learning group of debtor financing dataset motorcycle. The decision tree is then interpreted into the form of decision rules that can be understood and used as a reference in processing the data of borrowers in determining the feasibility of prospective new borrowers. Feasibility value refers to the value of the destination parameter credit status. If the value of the credit is paid off status mean estimated prospective borrower is able to repay the loan in question, but if the credit status parameters estimated worth pull means candidates concerned debtor is unable to pay loans.. System testing is done by comparing the results of the testing data by learning data in three scenarios with the decision that the data is valid at over 70% for all case scenarios. Moreover, in generated tree  and generate rules takes fairly quickly, which is no more than 15 minutes for each test scenario

  6. Cultivating C4 crops in a changing climate: sugarcane in Ghana

    Science.gov (United States)

    Black, Emily; Vidale, Pier Luigi; Verhoef, Anne; Vianna Cuadra, Santiago; Osborne, Tom; Van den Hoof, Catherine

    2012-12-01

    Over the next few decades, it is expected that increasing fossil fuel prices will lead to a proliferation of energy crop cultivation initiatives. The environmental sustainability of these activities is thus a pressing issue—particularly when they take place in vulnerable regions, such as West Africa. In more general terms, the effect of increased CO2 concentrations and higher temperatures on biomass production and evapotranspiration affects the evolution of the global hydrological and carbon cycles. Investigating these processes for a C4 crop, such as sugarcane, thus provides an opportunity both to extend our understanding of the impact of climate change, and to assess our capacity to model the underpinning processes. This paper applies a process-based crop model to sugarcane in Ghana (where cultivation is planned), and the São Paulo region of Brazil (which has a well-established sugarcane industry). We show that, in the Daka River region of Ghana, provided there is sufficient irrigation, it is possible to generate approximately 75% of the yield achieved in the São Paulo region. In the final part of the study, the production of sugarcane under an idealized temperature increase climate change scenario is explored. It is shown that doubling CO2 mitigates the degree of water stress associated with a 4 °C increase in temperature.

  7. Perfect Octagon Quadrangle Systems with an upper C4-system and a large spectrum

    Directory of Open Access Journals (Sweden)

    Luigia Berardi

    2011-02-01

    Full Text Available An octagon quadrangle is the graph consisting of an 8-cycle (x1, x2,..., x8 with two additional chords: the edges {x1, x4} and {x5, x8}. An octagon quadrangle system of order ν and index λ [OQS] is a pair (X,H, where X is a finite set of ν vertices and H is a collection of edge disjoint octagon quadrangles (called blocks which partition the edge set of λKν defined on X. An octagon quadrangle system Σ=(X,H of order ν and index λ is said to be upper C4-perfect if the collection of all of the upper 4-cycles contained in the octagon quadrangles form a μ-fold 4-cycle system of order ν; it is said to be upper strongly perfect, if the collection of all of the upper 4-cycles contained in the octagon quadrangles form a μ-fold 4-cycle system of order ν and also the collection of all of the outside 8-cycles contained in the octagon quadrangles form a ρ-fold 8-cycle system of order ν. In this paper, the authors determine the spectrum for these systems, in the case that it is the largest possible.

  8. Development of Digital I and C System using C4ISR Architect Framework

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Jae Cheon [KEPCO, Ulsan (Korea, Republic of); Quang, Phamle [Ninh Thuan Nuclear Power Project Management Board, Province (Viet Nam)

    2014-08-15

    The architect framework for the digital I and C system is presented in this work. With rapid changes in digital I and C technology, there is a strong need to provide uniform methods to describe the system functions and their performance in context with the physical configuration and logical behavior. C4ISR framework would provide the process and method for the digital system in that it allows the three different views of operational, systems and services, and technical standards. Therefore, stake holders can share information that is related to the system interfaces, the actions or activities that those components perform, and rules or constraints for those activities from the initial state of system development. As a result, the life cycle cost and development time for the digital I and C system can also be optimized. These benefits can be obtained by introducing views and products to reveal the logical, behavioral, and performance characteristics of the architecture. To prove this approach, the plant protection system (PPS) is chosen and the measure of effectiveness (MOE) is evaluated. An MOE of PPS is introduced as: functional effectiveness, performance effectiveness, and interoperability effectiveness.

  9. Antiviral Activity of Hederasaponin B from Hedera helix against Enterovirus 71 Subgenotypes C3 and C4a

    National Research Council Canada - National Science Library

    Song, Jaehyoung; Yeo, Sang-Gu; Hong, Eun-Hye; Lee, Bo-Ra; Kim, Jin-Won; Kim, Jeonghoon; Jeong, Hyeongun; Kwon, Yongsoo; Kim, Hyunpyo; Lee, Sangwon; Park, Jae-Hak; Ko, Hyun-Jeong

    2014-01-01

    Enterovirus 71 (EV71) is the predominant cause of hand, foot and mouth disease (HFMD). The antiviral activity of hederasaponin B from Hedera helix against EV71 subgenotypes C3 and C4a was evaluated in vero cells...

  10. Climate change drives a northward expansion of C4 grasses in North America by the end of the century

    Science.gov (United States)

    Cotton, J. M.; Mosier, T. M.; Cerling, T. E.; Ehleringer, J. R.; Hoppe, K. A.; Still, C. J.

    2016-12-01

    C4 grasses currently cover 18% of the earth's surface and are critically important as food sources, and account for roughly 25% of terrestrial productivity. Yet in the future these patterns will change as a result of the opposing impacts of atmospheric CO2 and climate on C3 and C4 physiologies. Here, we use the carbon isotope ratio (d13C) of modern and fossil bison and mammoth tissues as a proxy for the abundance of C3 and C4 vegetation across North American habitats. We then combine stable isotope data with CMIP5 climate model simulations, and used eight different climatic predictor variables and advanced statistical techniques to model the spatial distributions of C3 and C4 grasses from today through the year 2100 for two fossil-fuel emissions scenarios. For both scenarios, our vegetation model predicts increases in C4 grass abundance of up to 50% in the northern Great Plains and moderate decreases in C4 grass abundance in the central and southern Great Plains. The overall effect of these C3/C4 distribution changes will be a decreases in the magnitude of the north-south grass gradient in the Great Plains ecoregion with the loss of the highest abundance of C4 ecosystems in the panhandles of Texas, Oklahoma and western Kansas. These results have important implications for future changes in animal and plant biodiversity, agricultural productivity, and C4 grass invasions in North America. Our study suggests that changing climates will likely start to favor C4 crops over C3 crops in the northern Great Plains, potentially influencing the nature of different grain food supplies. Additionally, changes in C3 and C4 grass distributions, including decreases in the abundance of C3 grasses in native grasslands in the northern Great Plains, could have negative effects on the fauna that feed preferentially on those C3 grasses, and may also reduce also the number of unique habitats that currently maintain high biodiversity.

  11. Carbon isotopic evidence from paleosols for mixed C 3/C 4 vegetation in the Bogota Basin, Colombia

    Science.gov (United States)

    Mora, Germán; Pratt, Lisa M.

    2002-04-01

    Pollen reconstructions in the Bogota basin (Colombia) indicate the expansion of tropical high-altitude grassland (paramo) at the expense of Andean forests during glacial intervals. The carbon isotopic composition (δ 13C) of soil organic matter (SOM) can be a useful indicator of changes in vegetation affecting grasslands because it distinguishes between two groups of grasses (C 3 and C 4) adapted to different ecological environments. Values of SOM δ 13C were determined in four weathering profiles containing both modern (Holocene) soils and paleosols formed during the Last Glacial Stage. These profiles are located along an altitudinal transect in the Bogota basin, extending from 2550 to 3100 m. Values of SOM δ 13C in the topsoil horizons reflect those of the native C 3 vegetation that currently dominates the ecosystems in the Colombian Andes. Although C 4 grasses are currently negligible in the basin, elevated SOM δ 13C values indicative of C 4 plants were found in two Holocene soils. Environmental changes or ancient agricultural activities could explain the increased abundance of these plants in the basin during the late Holocene. Isotopic values in the studied paleosols revealed the presence of a mixed C 3/C 4 vegetation in the basin during the Last Glacial Stage, thus indicating the expansion of C 4 grasses. We hypothesized that lowered pCO 2 and possibly reduced rainfall resulted in the colonization of the tropical Andes by lowland C 4 grasses despite of prevailing cooler temperatures.

  12. Synthesis and NMR-Study of 1-Trimethylsilyl Substituted Silole Anion [Ph4C4Si(SiMe3]−•[Li]+ and 3-Silolenide 2,5-carbodianions {[Ph4C4Si(n-Bu2]−2•2[Li]+, [Ph4C4Si(t-Bu2]−2•2[Li]+} via Silole Dianion [Ph4C4Si]−2•2[Li]+

    Directory of Open Access Journals (Sweden)

    Jang-Hwan Hong

    2013-08-01

    Full Text Available 1-Trimethylsilyl, 1-R (R = Me, Et, i-Bu-2,3,4,5-tetraphenyl-1-silacyclopentadiene [Ph4C4Si(SiMe3R] are synthesized from the reaction of 1-trimethylsilyl,1-lithio-2,3,4,5-tetraphenyl-1-silacyclopentadienide anion [Ph4C4SiMe3]−•[Li]+ (3 with methyl iodide, ethyl iodide, and i-butyl bromide. The versatile intermediate 3 is prepared by hemisilylation of the silole dianion [Ph4C4Si]−2•2[Li]+ (2 with trimethylsilyl chloride and characterized by 1H-, 13C-, and 29Si-NMR spectroscopy. 1,1-bis(R-2,3,4,5-tetraphenyl-1-silacyclopentadiene [Ph4C4SiR2] {R = n-Bu (7; t-Bu (8} are synthesized from the reaction of 2 with n-butyl bromide and t-butyl bromide. Reduction of 7 and 8 with lithium under sonication gives the respective 3-silolenide 2,5-carbodianions {[Ph4C4Si(n-Bu2]−2•2[Li]+ (10 and [Ph4C4Si(t-Bu2]−2•2[Li]+ (11}, which are characterized by 1H-, 13C-, and 29Si-NMR spectroscopy. Polarization of phenyl groups in 3 is compared with those of silole anion/dianion, germole anion/dianion, and 3-silolenide 2,5-carbodianions 10 and 11.

  13. Non-specific phospholipase C4 mediates response to aluminum toxicity in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Přemysl ePejchar

    2015-02-01

    Full Text Available Aluminum ions (Al have been recognized as a major toxic factor for crop production in acidic soils. The first indication of the Al toxicity in plants is the cessation of root growth, but the mechanism of root growth inhibition is largely unknown. Here we examined the impact of Al on the expression, activity and function of the non-specific phospholipase C4 (NPC4, a plasma membrane-bound isoform of NPC, a member of the plant phospholipase family, in Arabidopsis thaliana.We observed a lower expression of NPC4 using GUS assay and a decreased formation of labeled diacylglycerol, product of NPC activity, using fluorescently labeled phosphatidylcholine as a phospholipase substrate in Arabidopsis WT seedlings treated with AlCl3 for 2 h. The effect on in situ NPC activity persisted for longer Al treatment periods (8, 14 h. Interestingly, in seedlings overexpressing NPC4, the Al-mediated NPC-inhibiting effect was alleviated at 14 h. However, in vitro activity and localization of NPC4 were not affected by Al, thus excluding direct inhibition by Al ions or possible translocation of NPC4 as the mechanisms involved in NPC-inhibiting effect. Furthermore, the growth of tobacco pollen tubes rapidly arrested by Al was partially rescued by the overexpression of AtNPC4 while Arabidopsis npc4 knockout lines were found to be more sensitive to Al stress during long-term exposure of Al at low phosphate conditions.Our observations suggest that NPC4 plays a role in both early and long-term responses to Al stress.

  14. Effects of substitution on counterflow ignition and extinction of C3 and C4 alcohols

    KAUST Repository

    Alfazazi, Adamu

    2016-06-17

    Dwindling reserves and inherent uncertainty in the price of conventional fuels necessitates a search for alternative fuels. Alcohols represent a potential source of energy for the future. The structural features of an alcohol fuel have a direct impact on combustion properties. In particular, substitution in alcohols can alter the global combustion reactivity. In this study, experiments and numerical simulations were conducted to investigate the critical conditions of extinction and autoignition of n-propanol, 1-butanol, iso-propanol and iso-butanol in non-premixed diffusion flames. Experiments were carried out in the counterflow configuration, while simulations were conducted using a skeletal chemical kinetic model for the C3 and C4 alcohols. The fuel stream consists of the pre-vaporized fuel diluted with nitrogen, while the oxidizer stream is air. The experimental results show that autoignition temperatures of the tested alcohols increase in the following order: iso-propanol > iso-butanol > 1-butanol ≈ n-propanol. The simulated results for the branched alcohols agree with the experiments, while the autoignition temperature of 1-butanol is slightly higher than that of n-propanol. For extinction, the experiments show that the extinction limits of the tested fuels increase in the following order: n-propanol ≈ 1-butanol > iso-butanol > iso-propanol. The model suggests that the extinction limits of 1-butanol is slightly higher than n-propanol with extinction strain rate of iso-butanol and iso-propanol maintaining the experimentally observed trend. The transport weighted enthalpy (TWE) and radical index (Ri) concepts were utilized to rationalize the observed reactivity trends for these fuels.

  15. Metabolism of leukotriene C4 in gamma-glutamyl transpeptidase-deficient mice.

    Science.gov (United States)

    Carter, B Z; Wiseman, A L; Orkiszewski, R; Ballard, K D; Ou, C N; Lieberman, M W

    1997-05-09

    We have investigated the metabolism of leukotriene C4 (LTC4) in gamma-glutamyl transpeptidase (GGT)-deficient mice (Lieberman, M. W., Wiseman, A. L., Shi, Z-Z., Carter, B. Z., Barrios, R., Ou, C-N., Chevez-Barrios, P., Wang, Y., Habib, G. M., Goodman, J. C., Huang, S. L., Lebovitz, R. M., and Matzuk, M. M. (1996) Proc. Natl. Acad. Sci. U. S. A. 93, 7923-7926) and have found substantial conversion of LTC4 to leukotriene D4 by high performance liquid chromatography and continuous flow fast atom bombardment-tandem mass spectrometric analyses. LTC4-converting activity has a tissue distribution different from GGT with highest activity in spleen followed by small intestine, kidney, and pancreas and lower activity in liver and lung. The activity is membrane-bound and is inhibited by acivicin, a known inhibitor of GGT. The enzyme was partially purified from the small intestine of GGT-deficient mice by papain treatment and gel filtration chromatography. The partially purified fragment released by papain has an apparent molecular mass of 65-70 kDa and the same substrate specificity as the tissue homogenate. In addition to LTC4, S-decyl-GSH is also cleaved. GSH itself, oxidized GSH, and the synthetic substrates used to analyze GGT activity (gamma-glutamyl-p-nitroanilide and gamma-glutamyl-4-methoxy-2-naphthylamide) are not substrates for this newly discovered enzyme. These data demonstrate that in addition to GGT at least one other enzyme cleaves LTC4 in mice. To reflect this enzyme's preferred substrate, we suggest that it be named gamma-glutamyl leukotrienase.

  16. High-resolution Moho model for Greenland from EIGEN-6C4 gravity data

    Science.gov (United States)

    Steffen, Rebekka; Strykowski, Gabriel; Lund, Björn

    2017-06-01

    The crust-mantle boundary (the Moho) is a first order interface in the Earth and the depth to the Moho is therefore well studied in most regions. However, below regions which are covered by large ice sheets, such as Greenland and Antarctica, the Moho is only partly known and seismic data are difficult to obtain. Here, we take advantage of the global gravity model EIGEN-6C4, together with the Parker-Oldenburg algorithm, to estimate the depth to the Moho beneath Greenland and surroundings. The available free-air gravity data are corrected for the topographic effect and the effect of sedimentary basins. We also correct for the effect on gravity due to the weight of the ice sheet and the accompanying deflection of the Earth's surface, which has not previously been taken into account in gravity studies of currently glaciated regions. Our final Moho depth model for Greenland has an associated uncertainty of ±4.5 km for areas with sedimentary basins and ±4 km for areas without sedimentary basins. The model shows maximum Moho depths below east Greenland of up to 55 km and values less than 20 km offshore east Greenland. There is a marked increase in Moho depth of 10-15 km from northern to central Greenland, indicating a significant change in geology. A deep Moho at the northern coast of Greenland towards Ellesmere Island might be related to the location of the hot-spot track. Our Moho model is consistent with previous models, but has a higher lateral resolution of 0.1° and covers the entire area of on- and offshore Greenland.

  17. Response to elevated CO 2 from a natural spring in a C 4 ...

    African Journals Online (AJOL)

    ... the late season. CO2-responsiveness in the field generally followed the seasonal phenologies of each species, being greatest during the most active growth period. Keywords: climate change; gas exchange; photosynthetic regulation; stomatal conductance. African Journal of Range & Forage Science: 2002 19(2): 81-91 ...

  18. Genome-wide association study for serum complement C3 and C4 levels in healthy Chinese subjects.

    Directory of Open Access Journals (Sweden)

    Xiaobo Yang

    2012-09-01

    Full Text Available Complement C3 and C4 play key roles in the main physiological activities of complement system, and their deficiencies or over-expression are associated with many clinical infectious or immunity diseases. A two-stage genome-wide association study (GWAS was performed for serum levels of C3 and C4. The first stage was conducted in 1,999 healthy Chinese men, and the second stage was performed in an additional 1,496 subjects. We identified two SNPs, rs3753394 in CFH gene and rs3745567 in C3 gene, that are significantly associated with serum C3 levels at a genome-wide significance level (P = 7.33 × 10(-11 and P = 1.83 × 10(-9, respectively. For C4, one large genomic region on chromosome 6p21.3 is significantly associated with serum C4 levels. Two SNPs (rs1052693 and rs11575839 were located in the MHC class I area that include HLA-A, HLA-C, and HLA-B genes. Two SNPs (rs2075799 and rs2857009 were located 5' and 3' of C4 gene. The other four SNPs, rs2071278, rs3763317, rs9276606, and rs241428, were located in the MHC class II region that includes HLA-DRA, HLA-DRB, and HLA-DQB genes. The combined P-values for those eight SNPs ranged from 3.19 × 10(-22 to 5.62 × 10(-97. HBsAg-positive subjects have significantly lower C3 and C4 protein concentrations compared with HBsAg-negative subjects (P<0.05. Our study is the first GWAS report which shows genetic components influence the levels of complement C3 and C4. Our significant findings provide novel insights of their related autoimmune, infectious diseases, and molecular mechanisms.

  19. Epididymal C4b-binding protein is processed and degraded during transit through the duct and is not essential for fertility

    Science.gov (United States)

    Nonaka, Mayumi I.; Zsigmond, Eva; Kudo, Akihiko; Kawakami, Hayato; Yoshida, Kaoru; Yoshida, Manabu; Kawano, Natsuko; Miyado, Kenji; Nonaka, Masaru; Wetsel, Rick A.

    2014-01-01

    C4b-binding protein (C4BP) is known as one of the circulating complement regulators that prevents excessive activation of the host-defense complement system. We have reported previously that C4BP is expressed abundantly in the rodent epididymis, one of the male reproductive organs connecting the testis and vas deferens, where immature spermatozoa acquire their motility and fertilizing ability during their transit through the duct. Epididymal C4BP (EpC4BP) is synthesized androgen-dependently by the epithelial cells, secreted into the lumen, and bound to the outer membrane of the passing spermatozoa. In this study, we found that EpC4BP is secreted as a large oligomer, similar to the serum C4BP, but is digested during the epididymal transit and is almost lost from both the luminal fluid and the sperm surface in the vas deferens. Such a processing pattern is not known in serum C4BP, suggesting that EpC4BP and serum C4BP might have different functional mechanisms, and that there is a novel function of EpC4BP in reproduction. In addition, the disappearance of EpC4BP from the sperm surface prior to ejaculation suggests that EpC4BP works only in the epididymis and would not work in the female reproductive tract to protect spermatozoa from complement attack. Next, we generated C4BP-deficient (C4BP−/−) mice to examine the possible role of EpC4BP in reproduction. However, the C4BP−/− mice were fertile and no significant differences were observed between the C4BP−/− and wild-type mouse spermatozoa in terms of morphology, motility, and rate of the spontaneous acrosome reaction. These results suggest that EpC4BP is involved in male reproduction, but not essential for sperm maturation. PMID:25468721

  20. Validation of reference genes for quantitative RT-PCR normalization in Suaeda aralocaspica, an annual halophyte with heteromorphism and C4 pathway without Kranz anatomy

    Directory of Open Access Journals (Sweden)

    Jing Cao

    2016-02-01

    Full Text Available Reverse transcription quantitative real-time polymerase chain reaction (qRT-PCR is a powerful analytical technique for the measurement of gene expression, which depends on the stability of the reference gene used for data normalization. Suaeda aralocaspica, an annual halophyte with heteromorphic seeds and possessing C4 photosynthesis pathway without Kranz anatomy, is an ideal plant species to identify stress tolerance-related genes and compare relative expression at transcriptional level. So far, no molecular information is available for this species. In the present study, six traditionally used reference genes were selected and their expression stability in two types of seeds of S. aralocaspica under different experimental conditions was evaluated. Three analytical programs, geNorm, NormFinder and BestKeeper, were used to assess and rank the stability of reference gene expression. Results revealed that although some reference genes may display different transcriptional profiles between the two types of seeds, β-TUB and GAPDH appeared to be the most suitable references under different developmental stages and tissues. GAPDH was the appropriate reference gene under different germination time points and salt stress conditions, and ACTIN was suitable for various abiotic stress treatments for the two types of seeds. For all the sample pools, β-TUB served as the most stable reference gene, whereas 18S rRNA and 28S rRNA performed poorly and presented as the least stable genes in our study. UBQ seemed to be unsuitable as internal control under different salt treatments. In addition, the expression of a photosynthesis-related gene (PPDK of C4 pathway and a salt tolerance-related gene (SAT of S. aralocaspica were used to validate the best performance reference genes. This is the first systematic comparison of reference gene selection for qRT-PCR work in S. aralocaspica and these data will facilitate further studies on gene expression in this species

  1. A shock tube study of C4–C6 straight chain alkenes + OH reactions

    KAUST Repository

    Khaled, Fathi

    2016-06-28

    Alkenes are known to be good octane boosters and they are major components of commercial fuels. Detailed theoretical calculations and direct kinetic measurements of elementary reactions of alkenes with combustion radicals are scarce for C4 alkenes and they are practically absent for C5 and larger alkenes. The overall rate coefficients for the reaction of OH radical with 1-butene (CH CHCH CH, k ), 1-pentene (CH CHCH CH-CH, k ), cis/trans 2-pentene (CH CHCHCH CH, k and k ), 1-hexene (CH CHCH CH CH CH, k ) and cis/trans 2-hexene (CH CHCHCH CH CH, k and k ) were measured behind reflected shock waves over the temperature range of 833-1377K and pressures near 1.5atm. The reaction progress was followed by measuring mole fraction of OH radicals near 306.7nm using UV laser absorption technique. It is found that the rate coefficients of OH+trans-2-alkenes are larger than those of OH+cis-2-alkenes, followed by OH+1-alkenes. The derived Arrhenius expressions for the overall rate coefficients (in cm.mol.s) are:. kI=(4.83±0.03)104.T2.72±0.01.exp(940.8±2.9cal/molRT)(946K-1256K) + kII=(5.66±0.54)10-1.T4.14±0.80.exp(4334±227cal/molRT)(875K-1379K) + kIII=(3.25±0.12)104.T2.76±0.5.exp(1962±83cal/molRT)(877K-1336K) + kIV=(3.42±0.09)104.T2.76±0.5.exp(1995±59cal/molRT)(833K-1265K) + kV=(7.65±0.58)10-4.T5±1.exp(5840±175cal/molRT)(836K-1387K) + kVI=(2.58±0.06)106.T2.17±0.37.exp(1461±55cal/molRT)(891K-1357K) + kVII=(3.08±0.05)106.T2.18±0.37.exp(1317±38cal/molRT)(881K-1377K) +

  2. Effects of Temperature and Humidity on the Characterization of C-4 Explosive Threats

    Science.gov (United States)

    Miller, C. J.; Yoder, T. S.

    2012-06-01

    Both the quantity and the amount of time that an explosive is present on the surface of a material is dependent upon the amount of explosive originally deposited on the surface, the adhesive forces, temperature and humidity, as well as other environmental factors. This laboratory study focused on evaluating RDX crystal morphology changes resulting from variations in temperature and humidity conditions of the sample. The temperature and humidity conditions were controlled using a Tenney THRJ environmental chamber and a Tenney T11RC-1.5 environmental chamber. These chambers allow the temperature and humidity to be held within ±3 °C and ±5 % RH. The temperature and humidity conditions used for this test series were: 4 °C/40 %RH, 21 °C/20 %RH (samples left on benchtop), 21 °C/70 %RH, 21 °C/95 %RH, 35 °C/40 %RH, 35 °C/70 %RH, and 35 °C/95 %RH. These temperature and humidity set points were chosen to represent a wide range of conditions that may be found in real world scenarios. C-4 (RDX crystals and binder material) was deposited on the surface of one of six substrates by placing a fingerprint from the explosive block onto the matrix surface. The substrates were chosen to provide a range of items that are commonly used. Six substrate types were used during these tests: 50 % cotton/50 % polyester as found in T-shirts, 100 % cotton with a smooth surface such as that found in a cotton dress shirt, 100 % cotton on a rough surface such as that found on canvas or denim, suede leather such as might be found on jackets, purses, or shoes, painted metal obtained from a car hood, and a computer diskette. The samples were not pre-cleaned prior to testing and contained sizing agents, and in the case of the metal: oil, dirt, scratches, and rust spots. The substrates were photographed at various stages of testing, using a Zeiss Discover V12 stereoscope with Axiocam ICc1 3 megapixel digital camera, to determine any changes in the crystalline morphology. Some of the samples

  3. You're so vein: bundle sheath physiology, phylogeny and evolution in C3 and C4 plants.

    Science.gov (United States)

    Griffiths, Howard; Weller, George; Toy, Lydia F M; Dennis, Ross J

    2013-02-01

    Bundle sheath (BS) anatomy is found in most C4 lineages, associated with low inter-veinal distances (IVD) and high BS:mesophyll ratio (BS:MC). The origins, function and selective advantages of the BS in C3 lineages are relevant for understanding the environmental, molecular and phylogenetic determinants of C4 evolution. Suggested functions for BS have included structural support, hydraulic isolation, storage for water, ions, and carbohydrates, and photorespiratory carbon metabolism; we propose a central role for cavitation repair, consistent with the BS as a control centre on regulating stem and leaf hydraulic continuity. An analysis of BS traits in the phylogenetic lineages giving rise to C4 grasses (the 'PACMAD' clade) shows an initial enhancement in BS:MC ratio in C3 lineages, although IVD is similar to the Pooideae sister group. Using a global database, a well-developed BS in the C3 PACMAD lineages was associated with higher precipitation and temperatures in the habitat of origin on an annual basis, with the C3 to C4 progression defined by the aridity index (AI). Maintaining leaf hydraulic conductance and cavitation repair are consistent with increased evaporative demand and more seasonal precipitation as drivers, first for the C3 BS, and then C4 diversification, under declining CO(2) concentrations in the Palaeogene and Neogene. © 2012 Blackwell Publishing Ltd.

  4. Late Pleistocene C 4Plant Dominance and Summer Rainfall in the Southwestern United States from Isotopic Study of Herbivore Teeth

    Science.gov (United States)

    Connin, Sean L.; Betancourt, Julio; Quade, Jay

    1998-09-01

    Patterns of climate and C 4plant abundance in the southwestern United States during the last glaciation were evaluated from isotopic study of herbivore tooth enamel. Enamel δ 13C values revealed a substantial eastward increase in C 4plant consumption for Mammuthusspp., Bisonspp., Equusspp., and Camelopsspp. The δ 13C values were greatest in Bisonspp. (-6.9 to +1.7‰) and Mammuthusspp. (-9.0 to +0.3‰), and in some locales indicated C 4-dominated grazing. The δ 13C values of Antilocaprids were lowest among taxa (-12.5 to -7.9‰) and indicated C 3feeding at all sites. On the basis of modern correlations between climate and C 4grass abundance, the enamel data imply significant summer rain in parts of southern Arizona and New Mexico throughout the last glaciation. Enamel δ 18O values range from +19.0 to +31.0‰ and generally increase to the east. This pattern could point to a tropical or subtropical source of summer rainfall. At a synoptic scale, the isotope data indicate that interactions of seasonal moisture, temperature, and lowered atmospheric pCO 2determined glacial-age C 4abundance patterns.

  5. Quantitative light microscopic autoradiographic study on (/sup 3/H)leukotriene C4 binding to nonpregnant bovine uterine tissue

    Energy Technology Data Exchange (ETDEWEB)

    Chegini, N.; Rao, C.V.

    1988-05-01

    Mammalian uteri contain both lipoxygenase and cyclooxygenase pathways of arachidonic acid metabolism. Sulfidopeptidyl leukotrienes formed by the lipoxygenase pathway can stimulate uterine contractions and play a role in uterine preparation for implantation. These actions of leukotrienes are perhaps mediated by binding to specific receptors. To understand the cellular basis of leukotriene C4 action, the present quantitative light microscopic autoradiographic study was undertaken on nonpregnant bovine uterine tissue. The results demonstrated that the circular and elongated myometrial smooth muscle, uterine vascular smooth muscle, stromal cells of endometrium, and fibroblasts of perimetrium, but not the endometrial glands, vascular endothelium, and erythrocytes in lumen of arterioles, contained specific silver grains after incubation with (/sup 3/H)leukotriene C4. The number of grains per 100-micron2 areas were similar in circular and elongated myometrial smooth muscle (P greater than 0.05), which was higher than in other uterine cells (P less than 0.05-0.01). The grains in all cells were greatly reduced after coincubation with excess unlabeled leukotriene C4, but not with leukotriene A4, leukotriene B4, leukotriene D4, leukotriene E4, prostaglandin E2, prostaglandin F2 alpha, or prostacyclin. In conclusion, leukotriene C4 may regulate both uterine cells and uterine vasculature and exert contractile and noncontractile actions via the specific leukotriene C4-binding sites present in different cell types.

  6. Similarity and Scaling of Turbulent Flame Speeds for Expanding Premixed Flames of C4-C8 n -alkanes

    Science.gov (United States)

    Wu, Fujia; Saha, Abhishek; Chaudhuri, Swetaprovo; Yang, Sheng; Law, Chung K.

    2013-11-01

    We experimentally investigated the propagation speed of constant-pressure expanding flames in near isotropic turbulence using a dual-chamber, fan-stirred vessel. The motivation is to test whether the fuel similarity concept among C4-C8 n-alkanes on laminar flames also holds for turbulent flames. Previously it was found that the laminar flame speed and Markstein length are almost identical for C4-C8 n-alkanes. If this fuel similarity concept can also be shown for turbulent flames, it will suggest a canonical flame structure for large hydrocarbon fuels, i . e . , large fuels always decompose to small C0-C4 fuel fragments before being oxidized, and would significantly simplify the description of the flames. Preliminary results show that in the flamelet and thin-reaction zone, turbulent flame speeds of C4-C8 n-alkanes are indeed largely similar at various conditions, thereby suggesting the fuel similarity for turbulent flames. In addition, it is found that the normalized turbulent flame speed also approximately scales with the square root of an appropriately-defined Reynolds number recently found for C0-C4 fuels. This work was supported by the AFOSR under the technical monitoring of Dr. Chiping Li.

  7. Volumetric Properties of the Mixture 2-Methylpropan-2-ol C4H10O + C4H10O2 Butane-1,3-diol (VMSD1211, LB4541_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture 2-Methylpropan-2-ol C4H10O + C4H10O2 Butane-1,3-diol (VMSD1211, LB4541_V)' providing data from direct low-pressure dilatometric measurement of molar excess volume at variable mole fraction and constant temperature.

  8. Volumetric Properties of the Mixture Thiolane 1,1-dioxide C4H8O2S+C4H10O 2-Methylpropan-2-ol (VMSD1111, LB3635_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Thiolane 1,1-dioxide C4H8O2S + C4H10O 2-Methylpropan-2-ol (VMSD1111, LB3635_V)' providing data from direct low-pressure measurement of mass density at variable mole fraction and constant temperature, in the single-phase region(s).

  9. Volumetric Properties of the Mixture Thiolane 1,1-dioxide C4H8O2S + C4H10O 2-Methylpropan-2-ol (VMSD1212, LB3632_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Thiolane 1,1-dioxide C4H8O2S + C4H10O 2-Methylpropan-2-ol (VMSD1212, LB3632_V)' providing data by calculation of molar excess volume from low-pressure density measurements at variable mole fraction and constant temperature.

  10. Vapor-Liquid Equilibrium in the Mixture 1,4-Dioxane C4H8O2 + C4H10O 2-Methylpropan-2-ol (EVLM1111, LB5683_E)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'vapor-Liquid Equilibrium in the Mixture 1,4-Dioxane C4H8O2 + C4H10O 2-Methylpropan-2-ol (EVLM1111, LB5683_E)' providing data from direct measurement of pressure at variable mole fraction in liquid phase and constant temperature.

  11. Vapor-Liquid Equilibrium in the Mixture 1,4-Dioxane C4H8O2 + C4H10O 2-Methylpropan-2-ol (EVLM1211, LB5686_E)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'vapor-Liquid Equilibrium in the Mixture 1,4-Dioxane C4H8O2 + C4H10O 2-Methylpropan-2-ol (EVLM1211, LB5686_E)' providing data from direct measurement of temperature at variable mole fraction in liquid phase and constant pressure.

  12. The Anticomplementary Activity of ’Fusobacterium polymorphum’ in Normal and C-4 Deficient Sources of Guinea Pig Complement.

    Science.gov (United States)

    1977-01-12

    Plaque on Epoxy Resin Crowns in Man. 3. Periodontol. 46: 10—26. S ! S ~ L 5- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 20a...C-4 Deficient GP sera (C4D). The C4D was kindly provided by Dr. Jerry A. Winkelstein, Depart- ment of Pediatrics , The Johns Hopkins School of

  13. SYNTHESIS AND MAGNETIC PROPERTIES OF BINUCLEAR COMPLEX [N(n-C4H94][MnIIFeIII(ox3

    Directory of Open Access Journals (Sweden)

    Fahimah Martak

    2012-02-01

    Full Text Available Binuclear complex, [N(n-C4H94][MnIIFeIII(ox3] (ox=oxalate, has been synthesized and characterized. Binuclear complex with formula of [N(n-C4H94][MnIIFeIII(ox3] was synthesized by forming precursor K3[Fe(ox3] which was followed by adding manganese chloride and tetrabutyl ammonium chloride. Characterization of the complex was made by microanalysis, FT-IR spectroscopy, x-ray diffraction and Magnetic Susceptibility Balance. Magnetic moment of binuclear complex [N(n-C4H94][MnIIFeIII(ox3] is 7.81 BM. The compound has higher magnetic moment than the previously reported compound with different organic cation, [N(n-C5H114][MnIIFeIII(ox3]. This behavior might be associated with the decreasing range among layers on polymeric network.

  14. Complement factors C4 and C3 are down regulated in response to short term overfeeding in healthy young men

    DEFF Research Database (Denmark)

    Foghmar, Caroline; Brøns, Charlotte; Pilely, Katrine

    2017-01-01

    -days HFO by a hyperinsulinemic-euglycemic-clamp. Circulating C4, C3, ficolins, mannose-binding-lectin, complement activation products C3bc, terminal complement complex (TCC) and complement activation capacity were determined using turbidimetry and ELISA. HFO induced peripheral insulin resistance in LBW...... individuals only, while both groups had the same degree of hepatic insulin resistance after HFO. Viewing all individuals circulating levels of C4, C3, C3bc, TCC and complement activation capacity decreased paradoxically along the development of insulin resistance after HFO (P = 0.0015, P

  15. Biosphere-atmosphere exchange of volatile organic compounds over C4 biofuel crops

    Science.gov (United States)

    Graus, Martin; Eller, Allyson S. D.; Fall, Ray; Yuan, Bin; Qian, Yaling; Westra, Philip; de Gouw, Joost; Warneke, Carsten

    2013-02-01

    Significant amounts of ethanol are produced from biofuel crops such as corn and, in the future, likely switchgrass. The atmospheric effects of growing these plant species on a large scale are investigated here by measuring the plant-atmosphere exchange of volatile organic compounds (VOCs). Field grown corn and switchgrass emit VOCs at flux rates of 4.4 nmolC m-2 s-1 (10-9 mol carbon per square meter leaf area per second) and 2.4 nmolC m-2 s-1, respectively. Methanol contributes ˜60% to the molar flux but small emissions of carbonyls, aromatic compounds and terpenoids are relatively more important for potential air quality impacts. Switchgrass can act as a sink for carbonyls and aromatic compounds with compensation points of a few hundred pptv. In switchgrass moderate drought stress may induce enhanced emissions of monoterpenes, carbonyls and aromatics. Per liter of fuel ethanol produced, the estimated VOC emissions associated with the biomass growth of corn (7.8 g l-1) or switchgrass (6.2 g l-1) are in the same range as the VOC emissions from the use of one liter gasoline in vehicle engines. VOC emissions from the growing of biofuel crops can therefore be a significant contributor to the VOC emissions in the life cycle of biofuels. The VOC emissions from corn and switchgrass are small compared to those of tree species suggested as biofuel crops. Due to their reactivity with respect to OH the emissions from corn and switchgrass are not likely to have a significant impact on regional ozone formation.

  16. Human blood and plasma partition coefficients for C4-C8 n-alkanes, isoalkanes, and 1-alkenes.

    Science.gov (United States)

    Mochalski, Paweł; King, Julian; Kupferthaler, Alexander; Unterkofler, Karl; Hinterhuber, Hartmann; Amann, Anton

    2012-06-01

    Human blood:air and plasma:air partition coefficients for C(4)-C(8) n-alkanes, isoalkanes, and 1-alkenes were determined using multiple headspace extraction coupled with solid phase microextraction and gas chromatography. Mean blood:air partition coefficients expressed in the form of dimensionless blood-to-air concentration ratio (g/mL(b)/g/mL(a)) were 0.183, 0.416, 1.08, 2.71, and 5.77 for C(4)-C(8) n-alkanes; 0.079, 0.184, 0.473, 1.3, and 3.18 for C(4)-C(8) isoalkanes; and 0.304, 0.589, 1.32, 3.5, and 7.01 for C(4)-C(8) 1-alkenes, respectively (n = 8). The reported partition coefficient values increased exponentially with boiling points, molecular weights, and the carbon atoms in the particle. The solubility of 1-alkenes in blood was higher than in plasma, whereas the blood:air and plasma:air partition coefficients of n-alkanes and isoalkanes did not differ significantly. Consequently, additional interactions of 1-alkenes with whole blood seem to occur. The presented findings are expected to be particularly useful for assessing the uptake, distribution, and elimination of hydrocarbons in human organism.

  17. You're so vein: bundle sheath physiology, phylogeny and evolution in C3 and C4 plants

    National Research Council Canada - National Science Library

    GRIFFITHS, HOWARD; WELLER, GEORGE; TOY, LYDIA F. M; DENNIS, ROSS J

    2013-01-01

    ...‐veinal distances (IVD) and high BS:mesophyll ratio (BS:MC). The origins, function and selective advantages of the BS in C3 lineages are relevant for understanding the environmental, molecular and phylogenetic determinants of C4 evolution...

  18. Elevated CO2 shifts the functional structure and metabolic potentials of soil microbial communities in a C4 agroecosystem

    Science.gov (United States)

    Xiong, Jinbo; He, Zhili; Shi, Shengjing; Kent, Angela; Deng, Ye; Wu, Liyou; van Nostrand, Joy D.; Zhou, Jizhong

    2015-03-01

    Atmospheric CO2 concentration is continuously increasing, and previous studies have shown that elevated CO2 (eCO2) significantly impacts C3 plants and their soil microbial communities. However, little is known about effects of eCO2 on the compositional and functional structure, and metabolic potential of soil microbial communities under C4 plants. Here we showed that a C4 maize agroecosystem exposed to eCO2 for eight years shifted the functional and phylogenetic structure of soil microbial communities at both soil depths (0-5 cm and 5-15 cm) using EcoPlate and functional gene array (GeoChip 3.0) analyses. The abundances of key genes involved in carbon (C), nitrogen (N) and phosphorus (P) cycling were significantly stimulated under eCO2 at both soil depths, although some differences in carbon utilization patterns were observed between the two soil depths. Consistently, CO2 was found to be the dominant factor explaining 11.9% of the structural variation of functional genes, while depth and the interaction of depth and CO2 explained 5.2% and 3.8%, respectively. This study implies that eCO2 has profound effects on the functional structure and metabolic potential/activity of soil microbial communities associated with C4 plants, possibly leading to changes in ecosystem functioning and feedbacks to global change in C4 agroecosystems.

  19. Biomass allocation and C-N-P stoichiometry in C3 and C4 crops under abiotic stress

    Science.gov (United States)

    Biomass allocation to structural, metabolic and reproductive organs as well as their carbon, nitrogen and phosphorus (C-N-P) profiles and ratios (C:N, C:P, and N:P) were estimated in C3 and C4 crop plants subjected to multiple abiotic stresses (i.e., combination of temperature and water stress level...

  20. Late pliocene-pleistocene expansion of C4 vegetation in semiarid East Asia linked to increased burning : Geology

    NARCIS (Netherlands)

    Zhou, B.; Shen, C.; Sun, W.; Bird, M.; Ma, W.; Taylor, D.; Liu, W.; Peterse, F.; Yi, W.; Zheng, H.

    2014-01-01

    Plants using the C4 photosynthetic pathway, commonly tropical and subtropical grasses, increased in abundance in East Asia during the late Cenozoic. Determining the exact timing and likely factors leading to this major vegetation change requires region-specific studies. Here variations in pyrogenic

  1. Penerapan Algoritma C4.5 untuk Klasifikasi Data Rekam Medis berdasarkan International Classification Diseases (ICD-10

    Directory of Open Access Journals (Sweden)

    Yudha Aditya Fiandra

    2017-10-01

    Full Text Available Abstract The medical record data is the patient's current record of medical records, the medical record data only being data stacked and not traced to generate useful knowledge for the hospital. This study can process the medical record data to classify the disease that occurs in sleeping sickness based on  ICD-10. The method used in this research is C4.5 algorithm method by using attribute of international disease code as attribute of destination label as many as 21 international disease group, that is: A00-B99 up to Z00-Z99. This study yields a decision of the value code, C4.5 code can represent as many as 14 attribute values ​​of disease code objectives and data percentage that read more than 66%. The conclusion of this research is C4.5 algorithm help classify international disease code based on ICD-10 and decision tree making which can give information of any disease that often happened at hospital  Keywords: data mining, classification, C4.5, medical records, ICD-10

  2. Atmospheric chemistry of 4:2 fluorotelomer alcohol (n-C4F9CH2CH2OH)

    DEFF Research Database (Denmark)

    Andersen, Mads Peter Sulbæk; Nielsen, Ole John; Hurley, M. D.

    2005-01-01

    Smog chamber/FTIR techniques were used to study the Cl atom initiated oxidation of 4:2 fluorotelomer alcohol (C4F9CH2CH2OH, 4:2 FTOH) in the presence of NOx in 700 Torr of N-2/O-2 diluent at 296 K. Chemical activation effects play an important role in the atmospheric chemistry of the peroxy...

  3. Evaluating the Effects of Elevated CO2 on the Competition Ability between Various C3 and C4 Crops and Weeds in Greenhouse Condition

    Directory of Open Access Journals (Sweden)

    S. Anvarkhah

    2012-04-01

    Full Text Available Since agriculture is both the source and sink of greenhouse gases, and plants show different responses to the elevated CO2 concentration, an experiment was conducted in 2006 at the research greenhouse of the faculty of agriculture of Ferdowsi University of Mashhad. The purpose of the experiment was to examine the effects of elevated CO2 on the competition ability between various crops and weeds in factorial arrangement within a completely randomized design with three replications. The factors included ambient (360ppm CO2 and elevated (700 ppm CO2 concentrations and various combinations of the plantation of crops (millet and soybean and weeds (pigweed and lambsquarters of C3 and C4 species, whether of the pure culture or intercropping. The results of the experiment showed that, as the CO2 concentration increased, the leaf area and root dry weight of millet increased whereas those of other species decreased. Millet,s root length increased whereas those of other species decreased. Root dry weight in each cultural combinations, compared to the ambient CO2 concentration, decreased. The amount of chlorophyll in lambsquarters, increased whereas it decreased in pigweed, millet and soybean.

  4. The impact of lower-limb prosthetic limb use in international C4 track para-cycling.

    Science.gov (United States)

    Dyer, Bryce

    2017-09-29

    An investigation was undertaken to ascertain any impact or significance of athletes within the C4 paracycling classification between those who use a lower-limb prostheses and those who do not. A statistical evaluation of event completion time was undertaken to assess C4 cyclists when competing at the World Championships and the Paralympic Games in the 1 km track time trial. The C4 athletes who utilize a prostheses consistently outperformed non-amputees in the C4 classification from 2011 to 2016 on a competition-to-competition basis. However, when the participations were grouped as a whole together and an identified outlier athlete was removed, it was then demonstrated that there was no statistical significance between those who required the use of a lower-limb prostheses to those that did not when either evaluated on a competition-by-competition or on an amputee and non-amputee group-by-group basis (p ≥ 0.05). As a result, this study proposes that those requiring the use of lower-limb prostheses are neither advantaged nor disadvantaged in the C4 classification category when competing in the 1 km time trial at this time. Implications for Rehabilitation This analysis indicates that at this time, there is no evidence to suggest that use of such technology is advantageous in this category or should be seen as controversial. The design of lower-limb prosthetic limb technology in cycling should continue to be developed and optimized unabated. This study begins to address the cited lack of peer-reviewed information regarding paracycling with limb absence available to practitioners.

  5. Characterization and expression patterns of key C4 photosynthetic pathway genes in bread wheat (Triticum aestivum L.) under field conditions.

    Science.gov (United States)

    Bachir, Daoura Goudia; Saeed, Iqbal; Song, Quanhao; Linn, Tay Zar; Chen, Liang; Hu, Yin-Gang

    2017-06-01

    Wheat is a C3 plant with relatively low photosynthetic efficiency and is a potential target for C4 photosynthetic pathway engineering. Here we reported the characterization of four key C4 pathway genes and assessed their expression patterns and enzymatic activities at three growth stages in flag leaves of 59 bread wheat genotypes. The C4-like genes homologous to PEPC, NADP-ME, MDH, and PPDK in maize were identified in the A, B, and D sub-genomes of bread wheat, located on the long arms of chromosomes 3 and 5 (TaPEPC), short arms of chromosomes 1 and 3 (TaNADP-ME), long arms of chromosomes 1 and 7 (TaMDH), and long arms of chromosome 1 (TaPPDK), respectively. All the four C4-like genes were expressed in the flag leaves at the three growth stages with considerable variations among the 59 bread wheat genotypes. Significant differences were observed between the photosynthesis rates (A) of wheat genotypes with higher expressions of TaPEPC_5, TaNADP-ME_1, and TaMDH_7 at heading and middle grain-filling stages and those with intermediate and low expressions. Our results also indicated that the four C4 enzymes showed activity in the flag leaves and were obviously different among the 59 wheat genotypes. The activities of PEPcase and PPDK decreased at anthesis and slightly increased at grain-filling stage, while NADP-ME and MDH exhibited a decreasing trend at the three stages. The results of the current study could be very valuable and useful for wheat researchers in improving photosynthetic capacity of wheat. Copyright © 2017 Elsevier GmbH. All rights reserved.

  6. Engineering Brevibacterium flavum for the production of renewable bioenergy: C4-C5 advanced alcohols.

    Science.gov (United States)

    Su, HaiFeng; Lin, JiaFu; Wang, YuanHong; Chen, Qiao; Wang, GuangWei; Tan, FuRong

    2017-09-01

    Biosynthesis of advanced biofuels by engineered non-natural microorganisms has been proposed to be the most promising approach for the replacement of dwindling fossil fuel resources. Brevibacterium flavum (Bf) is a model brevibacterium aerobe which lacks basic and applied research that could enable this species to produce biofuels. There are no reports regarding engineering this microorganism to produce advanced alcohols before. Here, for the first time, we developed the bacterium as a novel biosynthetic platform for advanced alcohols production via the mutagenesis and engineering to produce 2-ketoacids derived alcohols. In order to enhance the strain's capability of producing advanced alcohols, we preferentially improved intrinsic metabolism ability of the strain to obtain improved expression host (IEH) via generating mutagenesis libraries by whole cell mutagenesis (WCM). The IEH was determined via screening out the mutant strain with the highest production of branched-chain organic acids (BCOA) using high throughput screening method.. Subsequently, a novel vector system for Bf was established, and the corresponding biosynthetic pathway of directing carbon flux into the target advanced alcohols was recruited to make the bacterium possess the capability of producing advanced alcohols and further enhance the production using the IEH. Specifically, we generated bioengineered strains that were able to synthesize up to the highest 5362 and 4976 mg/L isobutanol, 1945 and 1747 mg/L 2-methyl-1-butanol (2 MB), and 785.34 and 781 mg/L 3-methyl-1-butanol (3 MB) from pure glucose and duckweed substrates, respectively. Our findings confirmed the feasibility and potential of using Bf as a novel biosynthetic platform to generate advanced biofuels with glucose and inexpensive renewable feedstock-duckweed as a fermentation substrate. Biotechnol. Bioeng. 2017;114: 1946-1958. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  7. New anatomical data on the growing C4 vertebra and its three ossification centers in human fetuses.

    Science.gov (United States)

    Baumgart, Mariusz; Szpinda, Michał; Szpinda, Anna

    2013-04-01

    Detailed knowledge on the normative growth of the spine is of great relevance in the prenatal diagnosis of its abnormalities. The present study was conducted to compile age-specific reference data for vertebra C4 and its three ossification centers in human fetuses. With the use of CT (Biograph mCT), digital image analysis (Osirix 3.9) and statistical analysis (Wilcoxon signed-rank test, Kolmogorov-Smirnov test, Levene's test, Student's t test, one-way ANOVA, post hoc RIR Tukey test, linear and nonlinear regression analysis), the normative growth of vertebra C4 and its three ossification centers in 55 spontaneously aborted human fetuses (27 males, 28 females) aged 17-30 weeks was examined. Significant differences in neither sex nor laterality were found. The height and transverse and sagittal diameters of the C4 vertebral body increased logarithmically as: y = -3.866 + 2.225 × ln(Age) ± 0.238 (R(2) = 0.69), y = -7.077 + 3.547 × ln(Age) ± 0.356 (R(2) = 0.72) and y = -3.886 + 2.272 × ln(Age) ± 0.222 (R(2) = 0.73), respectively. The C4 vertebral body grew linearly in cross-sectional area as y = -7.205 + 0.812 × Age ± 1.668 (R(2) = 0.76) and four-degree polynomially in volume as y = 14.108 + 0.00007 × Age(4) ± 6.289 (R(2) = 0.83). The transverse and sagittal diameters, cross-sectional area and volume of the ossification center of the C4 vertebral body generated the following functions: y = -8.836 + 3.708 × ln(Age) ± 0.334 (R(2) = 0.76), y = -7.748 + 3.240 × ln(Age) ± 0.237 (R(2) = 0.83), y = -4.690 + 0.437 × Age ± 1.172 (R(2) = 0.63) and y = -5.917 + 0.582 × Age ± 1.157 (R(2) = 0.77), respectively. The ossification center-to-vertebral body volume ratio gradually declined with age. On the right and left, the neural ossification centers showed the following growth: y = -19.601 + 8.018 × ln(Age) ± 0.369 (R(2) = 0.92) and y = -15.804 + 6.912 × ln(Age) ± 0.471 (R (2) = 0.85) for length, y = -5.806 + 2.587 × ln(Age) ± 0.146 (R(2) = 0.88) and y = -5

  8. What does leaf wax δD from a mixed C3/C4 vegetation region tell us?

    Science.gov (United States)

    Wang, Yiming V.; Larsen, Thomas; Leduc, Guillaume; Andersen, Nils; Blanz, Thomas; Schneider, Ralph R.

    2013-06-01

    Hydrogen isotope values (δD) of sedimentary terrestrial leaf wax such as n-alkanes or n-acids have been used to map and understand past changes in rainfall amount in the tropics because δD of precipitation is commonly assumed as the first order controlling factor of leaf wax δD. Plant functional types and their photosynthetic pathways can also affect leaf wax δD but these biological effects are rarely taken into account in paleo studies relying on this rainfall proxy. To investigate how biological effects may influence δD values we here present a 37,000-year old record of δD and stable carbon isotopes (δ13C) measured on four n-alkanes (n-C27, n-C29, n-C31, n-C33) from a marine sediment core collected off the Zambezi River mouth. Our paleo δ13C records suggest that each individual n-alkanes had different C3/C4 proportional contributions. n-C29 was mostly derived from a C3 dicots (trees, shrubs and forbs) dominant vegetation throughout the entire record. In contrast, the longer chain n-C33 and n-C31 were mostly contributed by C4 grasses during the Glacial period but shifted to a mixture of C4 grasses and C3 dicots during the Holocene. Strong correlations between δD and δ13C values of n-C33 (correlation coefficient R2 = 0.75, n = 58) and n-C31 (R2 = 0.48, n = 58) suggest that their δD values were strongly influenced by changes in the relative contributions of C3/C4 plant types in contrast to n-C29 (R2 = 0.07, n = 58). Within regions with variable C3/C4 input, we conclude that δD values of n-C29 are the most reliable and unbiased indicator for past changes in rainfall, and that δD and δ13C values of n-C31 and n-C33 are sensitive to C3/C4 vegetation changes. Our results demonstrate that a robust interpretation of palaeohydrological data using n-alkane δD requires additional knowledge of regional vegetation changes from which n-alkanes are synthesized, and that the combination of δD and δ13C values of multiple n-alkanes can help to differentiate

  9. Systems analysis of cis-regulatory motifs in C4 photosynthesis genes using maize and rice leaf transcriptomic data during a process of de-etiolation.

    Science.gov (United States)

    Xu, Jiajia; Bräutigam, Andrea; Weber, Andreas P M; Zhu, Xin-Guang

    2016-09-01

    Identification of potential cis-regulatory motifs controlling the development of C4 photosynthesis is a major focus of current research. In this study, we used time-series RNA-seq data collected from etiolated maize and rice leaf tissues sampled during a de-etiolation process to systematically characterize the expression patterns of C4-related genes and to further identify potential cis elements in five different genomic regions (i.e. promoter, 5'UTR, 3'UTR, intron, and coding sequence) of C4 orthologous genes. The results demonstrate that although most of the C4 genes show similar expression patterns, a number of them, including chloroplast dicarboxylate transporter 1, aspartate aminotransferase, and triose phosphate transporter, show shifted expression patterns compared with their C3 counterparts. A number of conserved short DNA motifs between maize C4 genes and their rice orthologous genes were identified not only in the promoter, 5'UTR, 3'UTR, and coding sequences, but also in the introns of core C4 genes. We also identified cis-regulatory motifs that exist in maize C4 genes and also in genes showing similar expression patterns as maize C4 genes but that do not exist in rice C3 orthologs, suggesting a possible recruitment of pre-existing cis-elements from genes unrelated to C4 photosynthesis into C4 photosynthesis genes during C4 evolution. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  10. Tumour cell expression of C4.4A, a structural homologue of the urokinase receptor, correlates with poor prognosis in non-small cell lung cancer

    DEFF Research Database (Denmark)

    Hansen, Line V.; Skov, Birgit G; Ploug, Michael

    2007-01-01

    expression. In the present study, we therefore explored the possible association between C4.4A expression and prognosis in patients with non-small cell lung cancer (NSCLC). EXPERIMENTAL DESIGN: Tissue sections from 108 NSCLC patients were subjected to immunohistochemical staining using a polyclonal antibody......PURPOSE: C4.4A expression has been implicated in human cancer progression. This protein is a structural homologue of the urokinase receptor, uPAR, which constitutes a well-established prognostic marker in various human cancers. Nonetheless, little is known about the prognostic significance of C4.4A...... that specifically recognises human C4.4A. Staining frequency and intensity was scored semiquantitatively and grouped into cancers with high and low expression of C4.4A. Kaplan-Meier survival curves were generated to evaluate the significance of C4.4A expression in prognosis of NSCLC patients. RESULTS: High C4.4A...

  11. Effects of methylation at position 2 of cation ring on rotational dynamics of imidazolium-based ionic liquids investigated by NMR spectroscopy: [C4mim]Br vs [C4C1mim]Br.

    Science.gov (United States)

    Endo, Takatsugu; Imanari, Mamoru; Seki, Hiroko; Nishikawa, Keiko

    2011-04-14

    We investigated the rotational dynamics of two imidazolium-based ionic liquids, 1-butyl-3-methylimidazolium bromide ([C(4)mim]Br) and 1-butyl-2,3-dimethylimidazolium bromide ([C(4)C(1)mim]Br), to reveal the effects of methylation at position 2 of the imidazolium ring (C(2) methylation). The rotational correlation time (τ(local)) for each carbon in the cations is derived from the spin-lattice relaxation time of (13)C nuclear magnetic resonance. The τ(local) results obtained here provide three principle insights into the rotational dynamics of ionic liquids. First, all τ(local) values for [C(4)C(1)mim]Br are greater than those for [C(4)mim]Br owing to a viscosity increase due to C(2) methylation. Second, the rate of change in τ(local) on C(2) methylation differs among the carbons in the cation, which indicates that each carbon has a different microviscosity. Third, the τ(local) increase in the (13)C at the root of the butyl group on C(2) methylation is very small compared to both intuitive prediction and the results from quantum chemical calculations. This indicates that the motion of the butyl group root in [C(4)C(1)mim]Br is not significantly inhibited by the methyl group at the position 2 of the imidazolium ring. The finding provides conclusive information on the origin of the increases in the melting point on C(2) methylation. Hunt previously found through calculation that decreases in entropy are caused by two factors, namely, reductions in the rotational mobility of the butyl group and in the number of stable anion interaction sites with C(2) methylation, resulting in an increase in melting point and viscosity. Our finding experimentally illustrates that the origin of the increases in melting point is not the inhibition of butyl group motion and that the reduction in stable anion interaction sites plays a major role in the increases. Additionally, it is suggested that the viscosity increase on C(2) methylation can be interpreted in the same manner.

  12. PENGEMBANGAN APLIKASI DATA MINING DENGAN ALGORITMA C4.5 DAN APRIORI DI FAKULTAS TEKNOLOGI INFORMATIKA UNIVERSITAS RESPATI INDONESIA

    Directory of Open Access Journals (Sweden)

    Yasmiati Yasmiati

    2017-01-01

    Full Text Available Kemampuan dosen yang baik akan berdampak positif terhadap kualitas layanan terhadap mahasiswa. Salah satu cara untuk mengetahui, memperbaiki, dan menjaga mutu dosen adalah dengan mengevaluasi kinerja dosen. Evaluasi atau penilaian kinerja harus dilakukan karena memiliki pengaruh yang kuat terhadap bentuk dan sifat hubungan kerja dalam suatu lembaga pendidikan. Data nilai mahasiswa dan data hasil evaluasi belum pernah dianalisis lebih mendalam sehingga data tersebut digunakan dengan penerapan menggunakan algoritma C4.5 dan Apriori dari metode Data Mining. Algoritma C4.5 untuk melakukan klasifikasi dengan hasil pembentukan pohon keputusan (decision tree. Sedangkan Algoritma Apriori digunakan dengan  cara pengkombinasian  Item dengan Item yang lainya dan menghasilkan nilai support dan confidence.

  13. Modeling and computations of the intramolecular electron transfer process in the two-heme protein cytochrome c4

    DEFF Research Database (Denmark)

    Natzmutdinov, Renat R.; Bronshtein, Michael D.; Zinkicheva, Tamara T.

    2012-01-01

    performed computational modeling of the intramolecular ET process by a combination of density functional theory (DFT) and quantum mechanical charge transfer theory to disclose reasons for this difference. We first address the electronic structures of the model heme core with histidine and methionine axial...... force were determined using dielectric continuum models. We then calculated the electronic transmission coefficient of the intramolecular ET rate using perturbation theory combined with the electronic wave functions determined by the DFT calculations for different heme group orientations and Fe......The di-heme protein Pseudomonas stutzeri cytochrome c4 (cyt c4) has emerged as a useful model for studying long-range protein electron transfer (ET). Recent experimental observations have shown a dramatically different pattern of intramolecular ET between the two heme groups in different local...

  14. KLASIFIKASI PENENTUAN TIM UTAMA OLAHRAGA HOCKEY MENGGUNAKAN ALGORITMA C4.5 (STUDI KASUS : HOCKEY KABUPATEN KENDAL

    Directory of Open Access Journals (Sweden)

    Budi Utami

    2016-12-01

    Full Text Available Klasifikasi pemain hockey dilakukan untuk mengklasifikasi pemain yang dapat lolos masuk tim utama dan gagal masuk tim utama. Klasifikasi dilakukan menggunakan data mining algoritma C4.5. Data yang digunakan untuk penelitian meliputi data multilevel pemain, data sprint, data tembakan push, data control bola, dan data game pemain. Proses data mining pada data training akan menghasilkan sebuah pohon keputusan atau rule. Metode evaluasi yang dilakukan dalam penelitian ini menggunakan confusion matrik dimana nilai akurasi untuk tiga kali pengujian mengalami kenaikan yaitu untuk prosentase data training dan data testing sebesar 70%:30% menghasilkan nilai akurasi sebesar 70%, prosentase data 80%:20% menghasilkan nilai akurasi sebesar 75%, dan untuk prosentase data 90%:10% menghasilkan nilai akurasi sebesar 80%. Ini membuktikan bahwa semakin besar data training maka semakin besar pula nilai akurasi yang didapat. Kata kunci : Hockey, klasifikasi, C4.5, data mining, confusion matrix

  15. OPTIMASI KLASIFIKASI SEL TUNGGAL PAP SMEAR MENGGUNAKAN CORRELATION BASED FEATURES SELECTION (CFS BERBASIS C4.5 DAN NAIVE BAYES

    Directory of Open Access Journals (Sweden)

    Asti Herliana

    2016-11-01

    Full Text Available Abstract – Cervical cancer was the most dangerous disease and generally attacks women. Early detection through Pap Smear method was one way to prevent the desease to grow in womans cervival canal. Based on the result of Pap Smear methode, the single cell of data that known as herlev data is available. This data, then used as a reference by the experts to find the best level classification from each class of cervical cancer. The decision tree C4.5 and Naïve Bayes have proven to give the best result on 280 data trial of herlev with support by Correlation based Features Selection (CFS optimization method. The issues raised in the present study was does CFS optimization methode that combined with the classification method of C4.5 and Naïve Bayes can provide increased the accuracy results when it faced the 917 data of herlev. The results of this study show that CFS method that combined either with C4.5 methods and naïve bayes classification accuracy was decrease when compared without using CFS method. In terms of showing that CFS can not provide the best result when if confronted with big data. Keywords : optimization, classification, single cell of Pap Smear, Correlation based Features Selection, C4.5, Naïve Bayes   Abstrak – Kanker serviks merupakan penyakit yang sangat berbahaya dan pada umumnya menyerang kaum wanita. Deteksi sejak dini melalui metode Pap Smear merupakan salah satu cara untuk mencegah penyakit ini berkembang didalam saluran serviks wanita. Berdasarkan hasil dari metode Pap Smear, didapatkanlah data sel tunggal yang kini dikenal dengan data herlev. Data ini, kemudian dijadikan acuan dalam penelitian oleh para ahli dewasa ini untuk menemukan tingkat klasifikasi terbaik dari masing-masing kelas kanker serviks. Metode Decision tree C4.5 dan Naïve Bayes terbukti memberikan hasil yang terbaik pada ujicoba data herlev sebanyak 280 data dengan dukungan dari metode optimasi Correlation based Features Selection(CFS. Permasalahan

  16. Approach to Interfacial and Intramolecular Electron Transfer of the Diheme Protein Cytochrome c(4) Assembled on Au(111) Surfaces

    DEFF Research Database (Denmark)

    Chi, Qijin; Zhang, Jingdong; Taner, Arslan

    2010-01-01

    Intramolecular electron transfer (ET) between metal centers is a core feature of large protein complexes in photosynthesis, respiration, and redox enzyme catalysis. The number of microscopic redox potentials and ET rate constants is, however, prohibitive for experimental cooperative ET mapping......, but two-center proteins are simple enough to offer complete communication networks. At the same time, multicenter redox proteins operate in membrane environments where conformational dynamics may lead to gated ET features different from conditions in homogeneous solution. The bacterial respiratory diheme...... protein Pseudomonas stutzeri cytochrome c(4) has been a target for intramolecular, interheme ET. We report here voltammetric and in situ scanning tunneling microscopy (STM) data for P. stutzeri cyt c(4) at single-crystal, atomically planar Au(111)-electrode surfaces modified by variable-length omega...

  17. Formation of octatetrayne (HC8H) from the reaction of butadiynyl (C4H) with butadiyne (HC4H)

    Science.gov (United States)

    Sun, Yi-Lun; Huang, Wen-Jian; Lee, Shih-Huang

    2017-12-01

    Reactants C4H and HC4H were synthesized from 1% C2H2/He in two crossed molecular beams by pulsed high-voltage discharge. We measured the angle-specific time-of-flight spectra and the photoionization-efficiency spectrum of product C8H2 using a crossed-molecular-beam quadrupole-mass apparatus and synchrotron vacuum-ultraviolet photoionization. The C8H2 product has translational energy stretching to the energetic limit of producing HC8H + H and has an ionization threshold 9.0 ± 0.1 eV in good agreement with that of HC8H. The quantum-chemical calculations are in accord with the experimental results. This work demonstrates that octatetrayne can be synthesized from the reaction C4H + HC4H → HC8H + H.

  18. Superoxide anion, superoxide dismutase and lipid peroxidation in the murine macrophage cell line C4M0

    Energy Technology Data Exchange (ETDEWEB)

    Imre, S.; Erdei, J.; Chihara, G.; Fachet, J.

    1985-01-01

    A remarkable increase in the production of superoxide radicals and superoxide dismutase (SOD) activity was measured in suspension of the murine macrophage cell line C4M0 treated with Lentinan (4-10 x 10/sup 3/ ..mu..g/5 x 10/sup 6/ cells). In activated macrophages the decrease of lipid peroxidation could be interpreted as a consequence of enhanced SOD activity.

  19. Anisotropy and polarization in charge changing collisions of C4+ with Na(3s) and laser aligned Na(3p)

    NARCIS (Netherlands)

    Hoekstra, R; Morgenstern, R; Olson, RE

    1996-01-01

    Absolute cross sections for C3+(6-->5) emission at 465.7 nm after collisions of C4+ ions with ground state Na(3s) and laser excited aligned Na(Sp) atoms are measured over the collision energy range of 3-7 keV amu(-1). For Na(3s) polarizations are observed by measuring the linear polarization of the

  20. Leukotriene C4 synthase and ischemic cardiovascular disease and obstructive pulmonary disease in 13,000 individuals

    DEFF Research Database (Denmark)

    Freiberg, Jacob J; Dahl, Morten; Tybjaerg-Hansen, Anne

    2009-01-01

    Ischemic cardiovascular disease and obstructive pulmonary disease involve inflammation. Leukotrienes may be important pro-inflammatory mediators. We tested the hypothesis that the (-1072)G > A and (-444)A > C promoter polymorphisms of leukotriene C4 synthase confer risk of transient ischemic attack...... (TIA), ischemic stroke, ischemic heart disease (IHD), asthma, and chronic obstructive pulmonary disease (COPD). We genotyped individuals from the Danish general population, the Copenhagen City Heart Study, and Danish patients with IHD/coronary atherosclerosis, the Copenhagen Ischemic Heart Disease...

  1. Synthesis and Cytotoxicity Evaluation of C4? and C5?Modified Analogues of the ?,??Unsaturated Lactone of Pironetin

    OpenAIRE

    Huang, David S.; Wong, Henry L.; Georg, Gunda I.

    2017-01-01

    Abstract Pironetin is a natural product with potent antiproliferative activity that forms a covalent adduct with ??tubulin via conjugate addition into the natural product's ?,??unsaturated lactone. Although pironetin's ?,??unsaturated lactone is involved in its binding to tubulin, the structure?activity relationship at different positions of the lactone have not been thoroughly evaluated. For a systematic evaluation of the structure?activity relationships at the C4 and C5 positions of the ?,?...

  2. Can the exceptional chilling tolerance of C4 photosynthesis found in Miscanthus × giganteus be exceeded? Screening of a novel Miscanthus Japanese germplasm collection.

    Science.gov (United States)

    Głowacka, Katarzyna; Jørgensen, Uffe; Kjeldsen, Jens B; Kørup, Kirsten; Spitz, Idan; Sacks, Erik J; Long, Stephen P

    2015-05-01

    A clone of the hybrid perennial C4 grass Miscanthus × giganteus (Mxg) is known for achieving exceptionally high rates of leaf CO2 uptake during chilling. This is a requisite of success in the early spring, as is the ability of the leaves to survive occasional frosts. The aim of this study was to search for genotypes with greater potential than Mxg for photosynthesis and frost survival under these conditions. A total of 864 accessions representing 164 local populations of M. sacchariflorus (Msa), M. sinensis (Msi) and M. tinctorius (Mti) collected across Japan were studied. Accessions whose leaves survived a natural late frost in the field were screened for high maximum photosystem II efficiency (Fv/Fm) following chilling weather, as an indicator of their capacity for light-limited photosynthesis. Those showing the highest Fv/Fm were transferred to a high-light-controlled environment and maintained at chilling temperatures, where they were further screened for their capacities for high-light-limited and light-saturated leaf uptake of CO2 (ΦCO2,max and Asat, respectively). For the first time, relatives of Mxg with significantly superior capacities for photosynthesis at chilling temperatures were identified. Msa accession '73/2' developed leaves in the spring that survived night-time frost, and during growth under chilling maintained a statistically significant 79 % higher ΦCO2,max, as a measure of light-limited photosynthesis, and a 70 % higher Asat, as a measure of light-saturated photosynthesis. A second Msa accession, '73/3' also showed significantly higher rates of leaf uptake of CO2. As remarkable as Mxg has proved in its chilling tolerance of C4 photosynthesis, this study shows that there is still value and potential in searching for yet more superior tolerance. Msa accession '73/2' shows rates of light-limited and light-saturated photosynthesis at chilling temperatures that are comparable with those of the most cold-tolerant C3 species. This adds

  3. Effects of gaseous ammonia on intracellular pH values in leaves of C 3- and C 4-plants

    Science.gov (United States)

    Yin, Zu-Hua; Kaiser, Werner; Heber, Ulrich; Raven, John A.

    Responses of cytosolic and vacuolar pH to different concentrations (1.3-5.4 μmol NH 3 mol -1 gas or 0.940-3.825 mg NH 3 m -3 gas) of gaseous NH 3 were studied in experiments of 3 h duration by recording changes in fluorescence of pyranine and esculin in leaves of C 3 and C 4 plants. After a lag phase of 0.5-4 min, the uptake of NH 3 at 50-200 nmol m -2 leaf area s -1 increased pyranine fluorescence, indicating cytosolic alkalinization in leaves of Pelargonium zonale L. (C 3) and Amaranthus caudatus L. (C 4). A smaller increase in esculin fluorescence induced by NH 3 indicated some vacuolar alkalization in a Spinacia oleracea L. leaf. Photosynthesis and transpiration remained unchanged during exposure of illuminated leaves to NH 3 for up to 30 min (the maximum tested). CO 2 concentrations influenced the extent of cytosolic alkalinization. 500 μmol CO 2 mol -1 gas suppressed the NH 3-induced cytosolic alkalinization relative to that found in 16 μmol CO 2 mol -1 gas. The suppressing effect of CO 2 on NH 3-induced alkalization was larger in illuminated leaves of the C 4Amaranthus than the C 3Pelargonium. These results indicate that the alkaline pH shift caused by solution and protonation of NH 3 in aqueous leaf compartments is affected by assimilation of NH 3.

  4. KLASIFIKASI CITRA PORNO DENGAN ALGORITMA C 4.5 BERBASIS MODEL WARNA YCbCr DAN SHAPE DETECTOR

    Directory of Open Access Journals (Sweden)

    Erwin Rizki Ariyanto

    2016-06-01

    Full Text Available Konten internet dapat berupa pornografi atau jebakan pornografi dengan tujuankorban anak di bawah umur. Tahun 2010 sebesar 97% remaja pernah mengaksescontent pronografi, dimana hal terebut berpengaruh negatif terhadap perkembangananak dan remaja. Dengan demikian akses terhadap pornografi oleh anak perlu dijaga.Beberapa penelitian telah menghasilkan aplikasi pendeteksi pornografi denganberbagai metode, seperti model warna YCbCr, shape descriptor yang saling mandiri.Dalam tulisan ini kami menyajikan klasifikasi citra porno dengan menggunakanalgoritma C 4.5 dan Shape descriptor berbasis model warna YCbCr. Klasifikasi denganC 4.5 merupakan tambahan metode perbaikan pada Shape Descriptor dan model warnaYCbCr dan di harapkan dapat secara presisi mengklasifikasikan citra porno dan bukan.Hasil dari percobaan terhadap 40 citra 8 bit dengan dimensi 256X256 yang terbagimenjadi citra porno, berbikini, mug shots dan non-porno, metode di atas dapatmengklasifikasikan True Positives (TP 16, False Positives (FP 10, False Negatives (FN 4,True Negatives (TN 10 dengan akurasi 65%, error rate 35%, precision 0,615, recall 0,8 sertanilai Root Mean Squared Error (RMSE 0,59.Semakin banyak data training semakin akurathasil dari testingnya, walaupun dalam beberapa kasus metode di atas belum akurat danhanya mengenail 3 dari 10 citra mug shots atau sebesar 43%.Kata Kunci: c 4.5, shape descriptor, model warna ycbcr, citra pornografi

  5. Classication of Status of the Region on Java Island using C4.5, CHAID, and CART Methods

    Science.gov (United States)

    Syaraswati, R. A.; Slamet, I.; Winarno, B.

    2017-06-01

    The indicator of region economic success can be measured by economic growth, presented by value of Gross Regional Domestic Product (GRDP). Java island has the biggest GDP contribution toward the Indonesian government, but not all of the region gives equality contribution. The C4.5, CHAID, and CART methods can be used for classifying the status of the region with nonparametric approach. The C4.5 and CHAID methods are non-binary decision tree, meanwhile the CART methods is binary decision tree. The purposes of this paper are to know how the classification and to determine the factors that influence on classification of the region. The dependent variable is status of the region which is divided into four categories based on Klassen typology. The result shows factors that have the biggest contribution on classification of status of the region on Java island based on C4.5 method are economic growth rate, electricity, gas, and water sector, and area. The factors that have the biggest contribution based on CHAID method are growth rate, manufacturing sector, and electricity, gas, and water sector, while based on CART method are growth rate, manufacturing sector, and electricity, gas, and water sector.

  6. IMPLEMENTASI DAN ANALISA HASIL DATA MINING UNTUK KLASIFIKASI SERANGAN PADA INTRUSION DETECTION SYSTEM (IDS DENGAN ALGORITMA C4.5

    Directory of Open Access Journals (Sweden)

    Izza Khaerani

    2015-10-01

    Full Text Available Intrusion Detection System (IDS merupakan sebuah kemampuan yang dimiliki oleh sebuah sistem atau perangkat untuk dapat melakukan deteksi terhadap serangan yang mungkin terjadi dalam jaringan baik lokal maupun yang terhubung dengan internet. Masalah dimulai ketika paket data yang datang sangat banyak dan harus di analisa di kemudian hari. Teknik Data Mining merupakan teknik yang tepat untuk melakukan analisa terhadap sebuah data. Beberapa penelitian telah menggunakan teknik data mining untuk mengatasi masalah serangan IDS seperti analisis frequent itemset, analisis clustering, analisis klasifikasi dan analisis asosiasi. Tujuan dari penelitian ini adalah untuk mengklasifikasikan serangan pada data-data yang diujikan dengan menggunakan metode klasifikasi dan algoritma klasifikasi C4.5. Penelitian ini menggunakan koleksi data dari KDD’99 dan memiliki 41 atribut dimana atribut ini dilakukan fitur seleksi untuk menghapus atribut yang tidak relevan dengan menggunakan teknik evolusi. Hasil yang didapatkan dari fitur seleksi ini adalah 16 atribut dengan akurasi tinggi mencapai 98,67% dari 41 atribut yang ada. Kemudian hasilnya dilakukan pemodelan dengan menggunakan algoritma C4.5 dan menghasilkan sebuah aturan untuk digunakan dalam implementasi sistem analisa klasifikasi data. Aturan yang dihasilkan dapat digunakan dalam sistem untuk mengklasifikasikan data serangan seperti dos, u2r, r2l dan probe serta aktifitas jaringan normal. Kata Kunci: Klasifikasi, Algoritma C4.5, Fitur Seleksi, Evolusi, Intrution Detection System, IDS.

  7. Integrative analysis and expression profiling of secondary cell wall genes in C4 biofuel model Setaria italica reveals targets for lignocellulose bioengineering

    Directory of Open Access Journals (Sweden)

    Mehanathan eMuthamilarasan

    2015-11-01

    Full Text Available Several underutilized grasses have excellent potential for use as bioenergy feedstock due to their lignocellulosic biomass. Genomic tools have enabled identification of lignocellulose biosynthesis genes in several sequenced plants. However, the non-availability of whole genome sequence of bioenergy grasses hinders the study on bioenergy genomics and their genomics-assisted crop improvement. Foxtail millet (Setaria italica L.; Si is a model crop for studying systems biology of bioenergy grasses. In the present study, a systematic approach has been used for identification of gene families involved in cellulose (CesA/Csl, callose (Gsl and monolignol biosynthesis (PAL, C4H, 4CL, HCT, C3H, CCoAOMT, F5H, COMT, CCR, CAD and construction of physical map of foxtail millet. Sequence alignment and phylogenetic analysis of identified proteins showed that monolignol biosynthesis proteins were highly diverse, whereas CesA/Csl and Gsl proteins were homologous to rice and Arabidopsis. Comparative mapping of foxtail millet lignocellulose biosynthesis genes with other C4 panicoid genomes revealed maximum homology with switchgrass, followed by sorghum and maize. Expression profiling of candidate lignocellulose genes in response to different abiotic stresses and hormone treatments showed their differential expression pattern, with significant higher expression of SiGsl12, SiPAL2, SiHCT1, SiF5H2 and SiCAD6 genes. Further, due to the evolutionary conservation of grass genomes, the insights gained from the present study could be extrapolated for identifying genes involved in lignocellulose biosynthesis in other biofuel species for further characterization.

  8. Comparative study for the detection of peritubular capillary C4d deposition in human renal allografts using different methodologies.

    Science.gov (United States)

    Nadasdy, Gyongyi M; Bott, Cherri; Cowden, Daniel; Pelletier, Ronald; Ferguson, Ronald; Nadasdy, Tibor

    2005-11-01

    Detection of peritubular capillary (PTC) C4d deposition in tissue sections of renal allograft biopsies became an important aid in the diagnosis of antibody-mediated rejection. Pathologists in many major transplant centers now routinely stain renal allograft biopsies for C4d. Currently, there are 3 commercially available antibodies. Two of these antibodies are monoclonal and are usually used with either a 3- or a 2-step indirect immunofluorescence (IF) methodology on frozen sections. A polyclonal antibody is used on formalin-fixed, paraffin-embedded tissue section with an immunoperoxidase detection system. The goal of our study was to compare these antibodies and methodologies in our renal allograft biopsy material. Twenty renal allograft biopsies with diffuse or focal PTC C4d staining, using immunofluorescence methods on frozen sections, were selected for this study. These biopsies were tested with the 3 commercially available anti-C4d antibodies (Biogenesis, Brentwood, Calif, cat no. 222-8004; Quidel Corporation, Santa Clara, Calif, cat no. A213; and ALPCO Diagnostic, Windham, NH, cat no. 004-BI-RC4D). Both monoclonal antibodies (Biogenesis and Quidel) were tested with a 3- and a 2-step indirect IF method on frozen sections. The polyclonal antibody (ALPCO) was applied to formalin-fixed paraffin sections using immunoperoxidase methodology. In selected cases, the polyclonal antibody was tested on frozen sections with a 3-step indirect IF method. To exclude possible false-negative staining with the IF method, we selected 10 additional biopsies that showed PTC margination of inflammatory cells, but were C4d-negative or only focally positive, and tested them with the ALPCO antibody on paraffin sections. We have found that all methodologies and antibodies tested provided adequate results with only minor differences between them. Perhaps the most sensitive method is the 3-step indirect IF on frozen sections using one of the monoclonal antibodies. We prefer the 2-step

  9. Evidence for development of capillary leak syndrome associated with cardiopulmonary bypass in pediatric patients with the homozygous C4A null phenotype.

    Science.gov (United States)

    Zhang, Shihai; Wang, Shouyong; Yao, Shanglong

    2004-06-01

    The mechanism of postoperative capillary leak syndrome related to cardiopulmonary bypass (CPB) is unknown. The authors hypothesized that C4 gene polymorphism might be involved in the development of the syndrome because complement activation is associated with CPB and protamine administration, and the two isotypes of C4 (C4A and C4B) differ in their biochemical and functional properties after activation. One hundred fifty-six pediatric patients referred for elective cardiac surgery with CPB were included in the study. C4 isotype studies were performed in plasma samples obtained before surgery, with use of agarose gel immunofixation and crossed immunoelectrophoresis. Five possible C4 phenotype groups were observed, which were abbreviated as follows: (1) AABB = no detectable null alleles, (2) A0BB = a single null allele (heterozygous) at the C4A locus, (3) 00BB = a homozygous C4A null allele, (4) AAB0 = a single null allele (heterozygous) at the C4B locus, and (5) AA00 = a homozygous C4B null allele. The patients were classified into five groups according to their C4 phenotypes. Before CPB and at 1 h after CPB, plasma protein was measured with a biuret test kit. Plasma colloid osmotic pressure was determined with a membrane osmometer. Evans blue dye was used to measure plasma volume, serum protein, intravenous protein pool, and transvascular escape rate of Evans blue dye. Of 156 pediatric patients enrolled, 80 were assigned to the AABB group, 28 were assigned to the A0BB group, 7 were assigned to the 00BB group, 31 were assigned to the AAB0 group, and 10 were assigned to the AA00 group, according to their C4 phenotypes. At 1 h after CPB, serum protein concentrations averaged 3.6 +/- 0.4 g/dl in patients with the 00BB C4 phenotype; this value was significantly lower (P < 0.01) than that in patients with other C4 phenotypes. The changes of intravenous protein pool and colloid osmotic pressure were comparable with the change in serum protein concentration. At 1 h after

  10. 40 CFR Table C-4 to Subpart C of... - Test Specifications for PM10, PM2.5 and PM10-2.5 Candidate Equivalent Methods

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 5 2010-07-01 2010-07-01 false Test Specifications for PM10, PM2.5 and PM10-2.5 Candidate Equivalent Methods C Table C-4 to Subpart C of Part 53 Protection of Environment... Pt. 53, Subpt. C, Table C-4 Table C-4 to Subpart C of Part 53—Test Specifications for PM10, PM2.5 and...

  11. The operation of two decarboxylases, transamination, and partitioning of C4 metabolic processes between mesophyll and bundle sheath cells allows light capture to be balanced for the maize C4 pathway.

    Science.gov (United States)

    Bellasio, Chandra; Griffiths, Howard

    2014-01-01

    The C4 photosynthesis carbon-concentrating mechanism in maize (Zea mays) has two CO2 delivery pathways to the bundle sheath (BS; via malate or aspartate), and rates of phosphoglyceric acid reduction, starch synthesis, and phosphoenolpyruvate regeneration also vary between BS and mesophyll (M) cells. The theoretical partitioning of ATP supply between M and BS cells was derived for these metabolic activities from simulated profiles of light penetration across a leaf, with a potential 3-fold difference in the fraction of ATP produced in the BS relative to M (from 0.29 to 0.96). A steady-state metabolic model was tested using varying light quality to differentially stimulate M or BS photosystems. CO2 uptake, ATP production rate (JATP; derived with a low oxygen/chlorophyll fluorescence method), and carbon isotope discrimination were measured on plants under a low light intensity, which is considered to affect C4 operating efficiency. The light quality treatments did not change the empirical ATP cost of gross CO2 assimilation (JATP/GA). Using the metabolic model, measured JATP/GA was compared with the predicted ATP demand as metabolic functions were varied between M and BS. Transamination and the two decarboxylase systems (NADP-malic enzyme and phosphoenolpyruvate carboxykinase) were critical for matching ATP and reduced NADP demand in BS and M when light capture was varied under contrasting light qualities.

  12. The Operation of Two Decarboxylases, Transamination, and Partitioning of C4 Metabolic Processes between Mesophyll and Bundle Sheath Cells Allows Light Capture To Be Balanced for the Maize C4 Pathway1[W

    Science.gov (United States)

    Bellasio, Chandra; Griffiths, Howard

    2014-01-01

    The C4 photosynthesis carbon-concentrating mechanism in maize (Zea mays) has two CO2 delivery pathways to the bundle sheath (BS; via malate or aspartate), and rates of phosphoglyceric acid reduction, starch synthesis, and phosphoenolpyruvate regeneration also vary between BS and mesophyll (M) cells. The theoretical partitioning of ATP supply between M and BS cells was derived for these metabolic activities from simulated profiles of light penetration across a leaf, with a potential 3-fold difference in the fraction of ATP produced in the BS relative to M (from 0.29 to 0.96). A steady-state metabolic model was tested using varying light quality to differentially stimulate M or BS photosystems. CO2 uptake, ATP production rate (JATP; derived with a low oxygen/chlorophyll fluorescence method), and carbon isotope discrimination were measured on plants under a low light intensity, which is considered to affect C4 operating efficiency. The light quality treatments did not change the empirical ATP cost of gross CO2 assimilation (JATP/GA). Using the metabolic model, measured JATP/GA was compared with the predicted ATP demand as metabolic functions were varied between M and BS. Transamination and the two decarboxylase systems (NADP-malic enzyme and phosphoenolpyruvate carboxykinase) were critical for matching ATP and reduced NADP demand in BS and M when light capture was varied under contrasting light qualities. PMID:24254314

  13. Structure, ferroelectric ordering, and semiempirical quantum calculations of lanthanide based metal-organic framework: [Nd(C4H5O6)(C4H4O6)][3H2O

    Science.gov (United States)

    Ahmad, Bhat Zahoor; Want, Basharat

    2016-04-01

    We investigate the structure and ferroelectric behavior of a lanthanide based metal-organic framework (MOF), [Nd(C4H5O6)(C4H4O6)][3H2O]. X-ray crystal structure analyses reveal that it crystallizes in the P41212 space group with Nd centres, coordinated by nine oxygen atoms, forming a distorted capped square antiprismatic geometry. The molecules, bridged by tartrate ligands, form a 2D chiral structure. The 2D sheets are further linked into a 3D porous framework via strong hydrogen-bonding scheme (O-H…O ≈ 2.113 Å). Dielectric studies reveal two anomalies at 295 K and 185 K. The former is a paraelectric-ferroelectric transition, and the later is attributed to the freezing down of the motion of the hydroxyl groups. The phase transition is of second order, and the spontaneous polarization in low temperature phase is attributed to the ordering of protons of hydroxyl groups. The dielectric nonlinearity parameters have been calculated using Landau- Devonshire phenomenological theory. In addition, the most recent semiempirical models, Sparkle/PM7, Sparkle/RM1, and Sparkle/AM1, are tested on the present system to assay the accuracy of semiempirical quantum approaches to predict the geometries of solid MOFs. Our results show that Sparkle/PM7 model is the most accurate to predict the unit cell structure and coordination polyhedron geometry. The semiempirical methods are also used to calculate different ground state molecular properties.

  14. Store-Independent Orai1/3 Channels Activated by Intracrine LeukotrieneC4: Role in Neointimal Hyperplasia

    Science.gov (United States)

    González-Cobos, José C.; Zhang, Xuexin; Zhang, Wei; Ruhle, Brian; Motiani, Rajender K.; Schindl, Rainer; Muik, Martin; Spinelli, Amy M.; Bisaillon, Jonathan M.; Shinde, Arti V.; Fahrner, Marc; Singer, Harold A.; Matrougui, Khalid; Barroso, Margarida; Romanin, Christoph; Trebak, Mohamed

    2013-01-01

    Rationale Through largely unknown mechanisms, Ca2+ signaling plays important roles in vascular smooth muscle cell (VSMC) remodeling. Orai1-encoded store-operated Ca2+ entry (SOCE) has recently emerged as an important player in VSMC remodeling. However, the role of the exclusively mammalian Orai3 protein in native VSMC Ca2+ entry pathways, its upregulation during VSMC remodeling and its contribution to neointima formation remain unknown. Objective The goal of this study was to determine the agonist-evoked Ca2+ entry pathway contributed by Orai3; Orai3 potential upregulation and role during neointima formation after balloon-injury of rat carotid arteries. Methods and Results Ca2+ imaging and patch clamp recordings showed that while the platelet-derived growth factor (PDGF) activates the canonical Ca2+ release-activated Ca2+ (CRAC) channels via store depletion in VSMC, the pathophysiological agonist thrombin activates a distinct Ca2+-selective channel contributed by Orai1, Orai3 and STIM1 in the same cells. Unexpectedly, Ca2+ store depletion is not required for activation of Orai1/3 channel by thrombin. Rather, the signal for Orai1/3 channel activation is cytosolic leukotrieneC4 produced downstream thrombin receptor stimulation through the catalytic activity of leukotrieneC4 synthase. Importantly, Orai3 is upregulated in an animal model of VSMC neointimal remodeling and in vivo Orai3 knockdown inhibits neointima formation. Conclusions These results demonstrate that distinct native Ca2+-selective Orai channels are activated by different agonists/pathways and uncover a mechanism whereby leukotrieneC4 acts through hitherto unknown intracrine mode to elicit store-independent Ca2+ signaling that promotes vascular occlusive disease. Orai3 and Orai3-containing channels provide novel targets for control of VSMC remodeling during vascular injury or disease. PMID:23349245

  15. Compound-specific stable carbon isotopic signature of carbohydrate pyrolysis products from C3 and C4 plants.

    Science.gov (United States)

    González-Pérez, José A; Jiménez-Morillo, Nicasio T; de la Rosa, José M; Almendros, Gonzalo; González-Vila, Francisco J

    2016-02-01

    Pyrolysis-compound specific isotopic analysis (Py-CSIA: Py-GC-(FID)-C-IRMS) is a relatively novel technique that allows on-line quantification of stable isotope proportions in chromatographically separated products released by pyrolysis. Validation of the Py-CSIA technique is compulsory for molecular traceability in basic and applied research. In this work, commercial sucrose from C4 (sugarcane) and C3 (sugarbeet) photosystem plants and admixtures were studied using analytical pyrolysis (Py-GC/MS), bulk δ(13)C IRMS and δ(13)C Py-CSIA. Major pyrolysis compounds were furfural (F), furfural-5-hydroxymethyl (HMF) and levoglucosan (LV). Bulk and main pyrolysis compound δ(13)C (‰) values were dependent on plant origin: C3 (F, -24.65 ± 0.89; HMF, -22.07 ± 0.41‰; LV, -21.74 ± 0.17‰) and C4 (F, -14.35 ± 0.89‰; HMF, -11.22 ± 0.54‰; LV, -11.44 ± 1.26‰). Significant regressions were obtained for δ(13)C of bulk and pyrolysis compounds in C3 and C4 admixtures. Furfural (F) was found (13)C depleted with respect to bulk and HMF and LV, indicating the incorporation of the light carbon atom in position 6 of carbohydrates in the furan ring after pyrolysis. This is the first detailed report on the δ(13)C signature of major pyrolytically generated carbohydrate-derived molecules. The information provided by Py-CSIA is valuable for identifying source marker compounds of use in food science/fraud detection or in environmental research. © 2015 Society of Chemical Industry.

  16. Command, Control, Communications, Computers, Intelligence Electronic Warfare (C4IEW) and Sensors. Project Book. Fiscal Year 1996

    Science.gov (United States)

    1996-01-01

    Weight (lbs) CPU Van 466.0" 98.0" 141.0" (est) 25,850 MSUVan 466.0" 98.0" 141.0" 25,254 Tape Library Van 466.0" 98.0" 141.0" 20,990 M109Van 263.0...MODIFIED/UPDATED VERSION OF THE TACCS WHICH UTILIZES THE INTEL 80386 PROCESSOR AND BTOS 2 FOR AN OPERATING SYSTEM. CECOM - C4ILRC 39-38 SMD SMD AN

  17. Deduced products of C4-dicarboxylate transport regulatory genes of Rhizobium leguminosarum are homologous to nitrogen regulatory gene products.

    OpenAIRE

    Ronson, C W; Astwood, P M; Nixon, B T; Ausubel, F M

    1987-01-01

    We have sequenced two genes dctB and dctD required for the activation of the C4-dicarboxylate transport structural gene dctA in free-living Rhizobium leguminosarum. The hydropathic profile of the dctB gene product (DctB) suggested that its N-terminal region may be located in the periplasm and its C-terminal region in the cytoplasm. The C-terminal region of DctB was strongly conserved with similar regions of the products of several regulatory genes that may act as environmental sensors, includ...

  18. Identification and sequence analysis of the Rhizobium meliloti dctA gene encoding the C4-dicarboxylate carrier.

    Science.gov (United States)

    Engelke, T; Jording, D; Kapp, D; Pühler, A

    1989-10-01

    Transposon Tn5-induced C4-dicarboxylate transport mutants of Rhizobium meliloti 2011 which could be complemented by cosmid pRmSC121 were subdivided into two classes. Class I mutants (RMS37 and RMS938) were defective in symbiotic C4-dicarboxylate transport and in nitrogen fixation. They were mutated in the structural gene dctA, which codes for the C4-dicarboxylate carrier. Class II mutants (RMS11, RMS16, RMS17, RMS24, and RMS31) expressed reduced activity in symbiotic C4-dicarboxylate transport and in nitrogen fixation. These mutants were mutated in regulatory dct genes which do not play an essential role in the symbiotic state. Thin sections of alfalfa nodules induced by the wild type and class I and class II mutants were analyzed by light microscopy. Class mutants induced typical Fix- nodules, showing a large senescent zone, whereas nodules induced by class II mutants only differed in an enhanced content of starch granules compared with wild-type nodules. Class I mutants could be complemented by a 2.1-kilobase SalI-HindIII subfragment of cosmid pRmSC121. DNA sequencing of this fragment resulted in the identification of an open reading frame, which was designated dctA because Tn5 insertion sites of the class I mutants mapped within this coding region. The dctA gene was preceded by a nif consensus promoter and an upstream NifA-binding element. Upstream of the dctA promoter, the 5' end of the R. meliloti dctB gene could be localized. The amino acid sequence of the N-terminal part of the R. meliloti DctB protein shared 49% homology with the corresponding part of the R. leguminosarum DctB protein. The DctA protein consisted of 441 or 453 amino acids due to two possible ATG start codons, with calculated molecular masses of 46.1 and 47.6 kilodaltons, respectively. The hydrophobicity plot suggests that DctA is a membrane protein with several membrane passages. The amino acid sequences of the R. meliloti and the R. leguminosarum DctA proteins were highly conserved (82%).

  19. Variations in IBD (ACAD8) in children with elevated C4-carnitine detected by tandem mass spectrometry newborn screening

    DEFF Research Database (Denmark)

    Pedersen, Christina B; Bischoff, Claus; Christensen, Ernst

    2006-01-01

    or compound heterozygous for variations in the IBD gene have been reported. We present IBD deficiency in an additional four newborns with elevated C(4)-carnitine identified by tandem mass spectrometry (MS/MS) screening in Denmark and the United States. Three showed urinary excretions of isobutyryl......-CoA dehydrogenase (SCAD) gene revealed heterozygosity for the prevalent c.625G>A susceptibility variation in all newborns and in the first reported IBD patient. Functional studies in isolated mitochondria demonstrated that the IBD variations present in the Danish newborn (c.409G>A and c.958G>A) together...

  20. The cross-neutralizing activity of enterovirus 71 subgenotype c4 vaccines in healthy chinese infants and children.

    Directory of Open Access Journals (Sweden)

    Qunying Mao

    Full Text Available BACKGROUND: EV71 is one of major etiologic causes of hand-foot-mouth disease (HFMD and leads to severe neurological complications in young children and infants. Recently inactivated EV71 vaccines have been developed by five manufactures and clinically show good safety and immunogenicity. However, the cross-neutralizing activity of these vaccines remains unclear, and is of particular interest because RNA recombination is seen more frequently in EV71 epidemics. METHODOLOGY/PRINCIPAL FINDINGS: In this post-hoc study, sera from a subset of 119 infants and children in two clinical trials of EV71 subgenotype C4 vaccines (ClinicalTrials.gov Identifier: NCT01313715 and NCT01273246, were detected for neutralizing antibody (NTAb titres with sera from infected patients as controls. Cytopathogenic effect method was employed to test NTAb against EV71 subgenotype B4, B5, C2, C4 and C5, which were prominent epidemic strains worldwide over the past decade. To validate the accuracy of the results, ELISpot assay was employed in parallel to detect NTAb in all the post-vaccine sera. After two-dose vaccination, 49 out of 53 participants in initially seronegative group and 52 out of 53 participants in initially seropositive group showed less than 4-fold differences in NTAb titers against five EV71 strains, whereas corresponding values among sera from pediatric patients recovering from EV71-induced HFMD and subclinically infected participants were 8/8 and 41/43, respectively. The geometric mean titers of participants against five subgenotypes EV71 all grew significantly after vaccinations, irrespective of the baseline NTAb titer. The relative fold increase in antibody titers (NTAb-FI against B4, B5, C2, and C5 displayed a positive correlation to the NTAb-FI against C4. CONCLUSIONS/SIGNIFICANCE: The results demonstrated broad cross-neutralizing activity induced by two C4 EV71 vaccines in healthy Chinese infants and children. However, the degree of induced cross

  1. Estimation of canopy nitrogen concentration across C3 and C4 grasslands using WorldView-2 multispectral data

    CSIR Research Space (South Africa)

    Adjorlolo, C

    2014-05-01

    Full Text Available production of plant functional types, litter decomposition, and rates of photosynthesis [1, 2]. The net primary production of quality biomass is one of the outcomes of complex interaction between vegetation and environment, which is one of the key factors...-band combination, have been used to improve the ability to predict the concentration per unit area of biochemicals at leaf or canopy scales [21-23]. The NDVI Estimation of canopy nitrogen concentration across C3 and C4 grasslands using WorldView-2 multispectral...

  2. Altered expression of the urokinase receptor homologue, C4.4A, in invasive areas of human esophageal squamous cell carcinoma

    DEFF Research Database (Denmark)

    Hansen, Line V.; Laerum, Ole D; Illemann, Martin

    2008-01-01

    . In the present study, we have therefore analyzed the expression of C4.4A in 14 esophageal squamous cell carcinomas (ESCC). Normal squamous esophageal epithelium shows a strong cell surface associated C4.4A expression in the suprabasal layers, whereas basal cells are negative. Upon transition to dysplasia...... and carcinoma in situ the expression of C4.4A is abruptly and coordinately weakened. Double immunofluorescence staining of normal and dysplastic tissue showed that C4.4A colocalizes with the epithelial cell surface marker E-cadherin in the suprabasal cells and has a complementary expression pattern compared...

  3. Synthesis of disodium [benzene-U-{sup 14}C]-(4-chlorophenylthio)methylenediphosphonate, [benzene-U-{sup 14}C]-tiludronate

    Energy Technology Data Exchange (ETDEWEB)

    Burgos, Alain; Ellames, G.J. [Alnwick Research Centre (United Kingdom). Dept. of Metabolism and Pharmacokinetics

    1995-12-31

    Disodium [benzene-U-{sup 14}C]-(4-chlorophenylithio)methylenediphosphonate, [benzene-{sup 14}C]-Tiludronate, 2, has been prepared in six steps from [benzene-U-{sup 14}C]-acetanilide in an overall radiochemical yield of 41%. A key step in this transformation was the efficient conversion of [U-{sup 14}C]-4-chloroaniline to [benzene-U-{sup 14}C]-4-chlorophenylthiocyanate, 5, in 83% yield by treatment of the corresponding diazonium salt, 9 with iron(111) thiocyanate. It should be noted that formation of the isomeric [benzene-U-{sup 14}C]-4-chlorophenylisothiocyanate, 11, as a byproduct, was observed in only {approx} 1% yield. (author).

  4. Two solid-phase recycling method for basic ionic liquid [C4mim]Ac by macroporous resin and ion exchange resin from Schisandra chinensis fruits extract.

    Science.gov (United States)

    Ma, Chun-hui; Zu, Yuan-gang; Yang, Lei; Li, Jian

    2015-01-22

    In this study, two solid-phase recycling method for basic ionic liquid (IL) 1-butyl-3-methylimidazolium acetate ([C4mim]Ac) were studied through a digestion extraction system of extracting biphenyl cyclooctene lignans from Schisandra chinensis. The RP-HPLC detection method for [C4mim]Ac was established in order to investigate the recovery efficiency of IL. The recycling method of [C4mim]Ac is divided into two steps, the first step was the separation of lignans from the IL solution containing HPD 5000 macroporous resin, the recovery efficiency and purity of [C4mim]Ac achieved were 97.8% and 67.7%, respectively. This method cannot only separate the lignans from [C4mim]Ac solution, also improve the purity of lignans, the absorption rate of lignans in [C4mim]Ac solution was found to be higher (69.2%) than that in ethanol solution (57.7%). The second step was the purification of [C4mim]Ac by the SK1B strong acid ion exchange resin, an [C4mim]Ac recovery efficiency of 55.9% and the purity higher than 90% were achieved. Additionally, [C4mim]Ac as solvent extraction of lignans from S. chinensis was optimized, the hydrolysis temperature was 90°C and the hydrolysis time was 2h. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Direct injection of human serum and pharmaceutical formulations for glucosamine determination by CE-C(4)D method.

    Science.gov (United States)

    Chaisuwan, Patcharin; Kongprasertsak, Thitiya; Sangcakul, Areeporn; Smith, Norman W; Nachapricha, Duangjai; Wilairat, Prapin; Uraisin, Kanchana

    2011-08-01

    A simple CE-C(4)D method has been developed for the determination of glucosamine by direct injection of human serum and pharmaceutical samples. Glucosamine was electrokinetically injected and analysed in its protonated form using 20mM MES/His (pH 6) as background electrolyte in order to separate it from the matrix and to provide a better response to the C(4)D detector. Separation of glucosamine in human serum and pharmaceutical samples was performed in 3 min without the need for protein precipitation or matrix removal. Good precision in terms of %RSD for the migration time and peak area were less than 1.91% (n = 10). The conductivity signal was linear with glucosamine concentration in the range 0.10-2.50mg/mL, with a detection limit of 0.03 mg/mL. Recoveries of glucosamine in serum and pharmaceutical samples were 86.5-104.78%. The method was successfully applied for the determination of the glucosamine content in pharmaceutical formulations and validated with high performance liquid chromatography (HPLC). Good agreements were observed between the developed method, label values and the HPLC method. Glucosamine could be detected in spiked serum sample by direct injection. This was not possible by HPLC due to co-eluting interferences. Copyright © 2011 Elsevier B.V. All rights reserved.

  6. Bacterial communities predominant in the degradation of 13C(4)-4,5,9,10-pyrene during composting.

    Science.gov (United States)

    Peng, Jingjing; Zhang, Yuan; Su, Jianqiang; Qiu, Qiongfen; Jia, Zhongjun; Zhu, Yong-Guan

    2013-09-01

    An in-vessel composting bioremediation of (13)C4-4,5,9,10-pyrene and unlabeled pyrene spiked soil amended with fresh wastes was investigated by DNA-based stable isotope probing (SIP) of active bacteria involved. Highest dissipation of (13)C4-pyrene was detected at 55 °C after 42 days composting. The active bacterial communities in the composting changed over time, showing a distinct difference among different stages. α-, β-, γ-Proteobacteria, and Actinobacteria were detected mainly involving in pyrene degradation at 38 °C over 14 days composting. Streptomyces appeared to dominate the pyrene degradation at 55 °C. β- and γ-Proteobacteria and Actinobacteria were the dominant pyrene degraders at 70 °C after 42 days composting and at 38 °C after 60 days composting. The results of this study suggest the pyrene degradation was performed by phylogenetically distinct bacterial guilds from the phyla Actinobacteria and Proteobacteria during in-vessel composition processes. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Use of a Pediatric Cardiovascular Nursing Consortium for Development and Evaluation of Quality Measures: The C4-MNP Experience.

    Science.gov (United States)

    Connor, Jean A; Larson, Carol; Baird, Jennifer; Hickey, Patricia A

    2016-01-01

    The evidence linking nursing care and patient outcomes has been globally demonstrated. Thus, it is time for translation and application of this evidence to robust measurement that uniquely demonstrates the value of nursing care and the characteristics of the nursing workforce that contribute to optimal patient outcomes. The aim of this study was to identify and develop standardized measures representative of pediatric nursing care of the cardiovascular patient for benchmarking within freestanding children's hospitals. Using a consensus-based approach, the Consortium of Congenital Cardiac Care- Measurement of Nursing Practice (C4-MNP) members developed quality measures within working groups and then individually critiqued all drafted measures. Final draft measures were then independently reviewed and critiqued by an external nursing quality measurement committee. The final quality measures were also made available to a national parent support group for feedback. The development process used by C4-MNP resulted in 10 measures eligible for testing across freestanding children's hospitals. Employing a collaborative consensus-based method plus implementing the criteria of the National Quality Forum and external vetting period provided a strong framework for the development and evaluation of standardized measures. The Consortium will continue with implementation and testing of each measure in 9 of our 28 collaborating centers. This activity will support initial development of benchmarks and evaluation of the association of the measures with patient outcomes. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Difference in C3-C4 metabolism underlies tradeoff between growth rate and biomass yield in Methylobacterium extorquens AM1.

    Science.gov (United States)

    Fu, Yanfen; Beck, David A C; Lidstrom, Mary E

    2016-07-19

    Two variants of Methylobacterium extorquens AM1 demonstrated a trade-off between growth rate and biomass yield. In addition, growth rate and biomass yield were also affected by supplementation of growth medium with different amounts of cobalt. The metabolism changes relating to these growth phenomena as well as the trade-off were investigated in this study. (13)C metabolic flux analysis was used to generate a detailed central carbon metabolic flux map with both absolute and normalized flux values. The major differences between the two variants occurred at the formate node as well as within C3-C4 inter-conversion pathways. Higher relative fluxes through formyltetrahydrofolate ligase, phosphoenolpyruvate carboxylase, and malic enzyme led to higher biomass yield, while higher relative fluxes through pyruvate kinase and pyruvate dehydrogenase led to higher growth rate. These results were then tested by phenotypic studies on three mutants (null pyk, null pck mutant and null dme mutant) in both variants, which agreed with the model prediction. In this study, (13)C metabolic flux analysis for two strain variants of M. extorquens AM1 successfully identified metabolic pathways contributing to the trade-off between cell growth and biomass yield. Phenotypic analysis of mutants deficient in corresponding genes supported the conclusion that C3-C4 inter-conversion strategies were the major response to the trade-off.

  9. Interactions of C4 Subtype Metabolic Activities and Transport in Maize Are Revealed through the Characterization of DCT2 Mutants.

    Science.gov (United States)

    Weissmann, Sarit; Ma, Fangfang; Furuyama, Koki; Gierse, James; Berg, Howard; Shao, Ying; Taniguchi, Mitsutaka; Allen, Doug K; Brutnell, Thomas P

    2016-02-01

    C4 photosynthesis in grasses requires the coordinated movement of metabolites through two specialized leaf cell types, mesophyll (M) and bundle sheath (BS), to concentrate CO2 around Rubisco. Despite the importance of transporters in this process, few have been identified or rigorously characterized. In maize (Zea mays), DCT2 has been proposed to function as a plastid-localized malate transporter and is preferentially expressed in BS cells. Here, we characterized the role of DCT2 in maize leaves using Activator-tagged mutant alleles. Our results indicate that DCT2 enables the transport of malate into the BS chloroplast. Isotopic labeling experiments show that the loss of DCT2 results in markedly different metabolic network operation and dramatically reduced biomass production. In the absence of a functioning malate shuttle, dct2 lines survive through the enhanced use of the phosphoenolpyruvate carboxykinase carbon shuttle pathway that in wild-type maize accounts for ∼ 25% of the photosynthetic activity. The results emphasize the importance of malate transport during C4 photosynthesis, define the role of a primary malate transporter in BS cells, and support a model for carbon exchange between BS and M cells in maize. © 2016 American Society of Plant Biologists. All rights reserved.

  10. Interaction of leukotriene C4 and Chinese hamster lung fibroblasts (V79A03 cells). 1. Characterization of binding

    Energy Technology Data Exchange (ETDEWEB)

    Fitz, T.A.; Contois, D.F.; Liu, Y.X.; Watt, D.S.; Walden, T.L.

    1990-10-01

    A novel, specific, and potent biological action of leukotriene C4 (LTC4) was demonstrated in the Chinese Hamster lung fibroblast cell line V79A03 (V79 cells), namely the conferment of protection against subsequent irradiation. Consequently, studies were conducted to determine whether LTC4-conferred radioprotection could be attributed to a receptor-mediated phenomenon. Specific binding sites for leukotriene C4 (LTC4) were identified and characterized using intact V79 cells incubated at 4 C in the presence of serine-borate, during which time conversion of LTC4 to LTD4 or LTE4 was undetectable. Binding was maximal in a broad region between pH 6.2 and 8.8. Ca2+, Mg2+, and Na+ were not required for binding, and binding was not altered by GTP, ATP, cAMP, by leukotrienes B4, D4, or E4, or by the leukotriene end point antagonists LY 171883, FPL 55712, or Revlon 5901-5.

  11. Hybrid Modified K-Means with C4.5 for Intrusion Detection Systems in Multiagent Systems

    Directory of Open Access Journals (Sweden)

    Wathiq Laftah Al-Yaseen

    2015-01-01

    Full Text Available Presently, the processing time and performance of intrusion detection systems are of great importance due to the increased speed of traffic data networks and a growing number of attacks on networks and computers. Several approaches have been proposed to address this issue, including hybridizing with several algorithms. However, this paper aims at proposing a hybrid of modified K-means with C4.5 intrusion detection system in a multiagent system (MAS-IDS. The MAS-IDS consists of three agents, namely, coordinator, analysis, and communication agent. The basic concept underpinning the utilized MAS is dividing the large captured network dataset into a number of subsets and distributing these to a number of agents depending on the data network size and core CPU availability. KDD Cup 1999 dataset is used for evaluation. The proposed hybrid modified K-means with C4.5 classification in MAS is developed in JADE platform. The results show that compared to the current methods, the MAS-IDS reduces the IDS processing time by up to 70%, while improving the detection accuracy.

  12. Hybrid Modified K-Means with C4.5 for Intrusion Detection Systems in Multiagent Systems.

    Science.gov (United States)

    Laftah Al-Yaseen, Wathiq; Ali Othman, Zulaiha; Ahmad Nazri, Mohd Zakree

    2015-01-01

    Presently, the processing time and performance of intrusion detection systems are of great importance due to the increased speed of traffic data networks and a growing number of attacks on networks and computers. Several approaches have been proposed to address this issue, including hybridizing with several algorithms. However, this paper aims at proposing a hybrid of modified K-means with C4.5 intrusion detection system in a multiagent system (MAS-IDS). The MAS-IDS consists of three agents, namely, coordinator, analysis, and communication agent. The basic concept underpinning the utilized MAS is dividing the large captured network dataset into a number of subsets and distributing these to a number of agents depending on the data network size and core CPU availability. KDD Cup 1999 dataset is used for evaluation. The proposed hybrid modified K-means with C4.5 classification in MAS is developed in JADE platform. The results show that compared to the current methods, the MAS-IDS reduces the IDS processing time by up to 70%, while improving the detection accuracy.

  13. Environmental Performance of Miscanthus, Switchgrass and Maize: Can C4 Perennials Increase the Sustainability of Biogas Production?

    Directory of Open Access Journals (Sweden)

    Andreas Kiesel

    2016-12-01

    Full Text Available Biogas is considered a promising option for complementing the fluctuating energy supply from other renewable sources. Maize is currently the dominant biogas crop, but its environmental performance is questionable. Through its replacement with high-yielding and nutrient-efficient perennial C4 grasses, the environmental impact of biogas could be considerably improved. The objective of this paper is to assess and compare the environmental performance of the biogas production and utilization of perennial miscanthus and switchgrass and annual maize. An LCA was performed using data from field trials, assessing the impact in the five categories: climate change (CC, fossil fuel depletion (FFD, terrestrial acidification (TA, freshwater eutrophication (FE and marine eutrophication (ME. A system expansion approach was adopted to include a fossil reference. All three crops showed significantly lower CC and FFD potentials than the fossil reference, but higher TA and FE potentials, with nitrogen fertilizer production and fertilizer-induced emissions identified as hot spots. Miscanthus performed best and changing the input substrate from maize to miscanthus led to average reductions of −66% CC; −74% FFD; −63% FE; −60% ME and −21% TA. These results show that perennial C4 grasses and miscanthus in particular have the potential to improve the sustainability of the biogas sector.

  14. A novel bagging C4.5 algorithm based on wrapper feature selection for supporting wise clinical decision making.

    Science.gov (United States)

    Lee, Shin-Jye; Xu, Zhaozhao; Li, Tong; Yang, Yun

    2017-11-11

    From the perspective of clinical decision-making in a Medical IoT-based healthcare system, achieving effective and efficient analysis of long-term health data for supporting wise clinical decision-making is an extremely important objective, but determining how to effectively deal with the multi-dimensionality and high volume of generated data obtained from Medical IoT-based healthcare systems is an issue of increasing importance in IoT healthcare data exploration and management. A novel classifier or predicator equipped with a good feature selection function contributes effectively to classification and prediction performance. This paper proposes a novel bagging C4.5 algorithm based on wrapper feature selection, for the purpose of supporting wise clinical decision-making in the medical and healthcare fields. In particular, the new proposed sampling method, S-C4.5-SMOTE, is not only able to overcome the problem of data distortion, but also improves overall system performance because its mechanism aims at effectively reducing the data size without distortion, by keeping datasets balanced and technically smooth. This achievement directly supports the Wrapper method of effective feature selection without the need to consider the problem of huge amounts of data; this is a novel innovation in this work. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Root distribution and interactions between allelopathic rice and c4 grass weed species as determined by 13c isotope discrimination analysis

    Science.gov (United States)

    Cultivars which carry allelopathic traits (traits that enable them to suppress weeds) could improve the economical management and sustainability of rice production. Interactions between roots of rice and weeds are thought to be modulated by the weed-suppressive activity of some rice cultivars, but ...

  16. Greenhouse gas flux under warm-season perennial C4 grasses across different soil and climate gradients on the Islands of Hawaii

    Science.gov (United States)

    Pawlowski, M. N.; Crow, S. E.; Sumiyoshi, Y.; Wells, J.; Kikkawa, H. R.

    2011-12-01

    Agricultural soils can serve as either a sink or a source for atmospheric carbon (C) and other greenhouse gases (GHG). This is particularly true for tropical soils where influences from climate and soil gradients are wide ranging. Current estimates of GHG flux from soil are often under or overestimated due to high variability in sample sites and inconsistencies in land use and vegetation type, making extrapolation to new study systems difficult. This work aimed to identify patterns of trace fluxes of carbon dioxide (CO2), nitrous oxide (N2O) and methane (CH4) across two soil types and three species of warm season perennial C4 grasses: Pennisetum purpureum (Napier grass), Panicum maximum (Guinea grass) and Saccharum officinarum (sugar cane) on the islands of Oahu and Maui in Hawaii. Multiple static vented chambers were installed into replicate plots for each species; flux measurements were made during the growth, fertilization and harvest cycles at set time intervals for one hour and analyzed by gas chromatography. Initial results from Oahu indicate no significant differences in CO2 flux between the P. maximum and P. purpureum species after fertilization or at full growth. We observed an average flux of 143 mg m-2 h-1 and 155 mg m-2 h-1 for P. maximum and P. purpureum respectively at full growth for CO2 and 1.7 μg m-2 h-1and 0.3 μg m-2 h-1 for N2O. Additionally, N2O rates sampled after a typical fertilizer application were significantly greater than at full growth (p=0.0005) with flux rates of 25.2 μg m2h-1 and 30.3 μg m2h-1 for P. maximum and P. purpureum respectively. With a global warming potential of 310 for N2O, even short-term spikes following fertilizer application can cause long lasting effects of GHG emission from agricultural soils. CH4 flux was negligible for all species on the Oahu plots during these sample periods. Globally, water limitation is a major factor influencing the potential productivity of agricultural crops and the sustainability of

  17. Expression of C4.4A, a structural uPAR homolog, reflects squamous epithelial differentiation in the adult mouse and during embryogenesis

    DEFF Research Database (Denmark)

    Kriegbaum, Mette Camilla; Jacobsen, Benedikte; Hald, Andreas

    2011-01-01

    -glandular portion of the rodent stomach, anus, vagina, cornea, and skin. This epithelial confinement was particularly evident from the abrupt termination of C4.4A expression at the squamo-columnar transition zones found at the ano-rectal and utero-vaginal junctions, for example. During mouse embryogenesis, C4.4A...

  18. Expression of recombinant Pseudomonas stutzeri di-heme cytochrome c(4) by high-cell-density fed-batch cultivation of Pseudomonas putida

    DEFF Research Database (Denmark)

    Thuesen, Marianne Hallberg; Nørgaard, Allan; Hansen, Anne Merete

    2003-01-01

    The gene of the di-heme protein cytochrome c(4) from Pseudomonas stutzeri was expressed in Pseudomonas putida. High-yield expression of the protein was achieved by high-cell-density fed-batch cultivation using an exponential glucose feeding strategy. The recombinant cytochrome c(4) protein...

  19. Sheep wool δ13C reveals no effect of grazing on the C3/C4 ratio of vegetation in the inner Mongolia-Mongolia border region grasslands.

    Science.gov (United States)

    Auerswald, Karl; Wittmer, Max H O M; Tungalag, Radnaakhand; Bai, Yongfei; Schnyder, Hans

    2012-01-01

    We tested whether the abundance of C(4) vegetation in grasslands of the Mongolian plateau is influenced by grazing conditions. The analysis exploited the politically originated contrast that exists between Mongolia (low stocking rate, transhumant system) and the district of Inner Mongolia, China (high stocking rate, sedentary system). We estimated the proportion of C(4) carbon (P(C4)) in grazed vegetation from the relative carbon isotope ratio (δ(13)C) of sheep wool sampled from 298 annual shearings originating from 1996 to 2007. Annual stocking rates varying over time and between the districts of both countries were taken from regional statistics. The P(C4) pattern within the 0.7 million km(2) sampling area was geostatistically analyzed and related to stocking rates and temperature gradients. For similar climatic conditions, P(C4) was the same in both countries. Further, a unique relationship was found between P(C4) and July temperature on both sides of the border, which explained 71% of the pattern. Stocking rate and grazing system had no significant influences on present-day C(3)/C(4) abundance ratio. This finding suggests that recent changes in the C(3)/C(4) ratio of these grasslands are mainly a consequence of regional warming, not overgrazing.

  20. Sheep wool δ13C reveals no effect of grazing on the C3/C4 ratio of vegetation in the inner Mongolia-Mongolia border region grasslands.

    Directory of Open Access Journals (Sweden)

    Karl Auerswald

    Full Text Available We tested whether the abundance of C(4 vegetation in grasslands of the Mongolian plateau is influenced by grazing conditions. The analysis exploited the politically originated contrast that exists between Mongolia (low stocking rate, transhumant system and the district of Inner Mongolia, China (high stocking rate, sedentary system. We estimated the proportion of C(4 carbon (P(C4 in grazed vegetation from the relative carbon isotope ratio (δ(13C of sheep wool sampled from 298 annual shearings originating from 1996 to 2007. Annual stocking rates varying over time and between the districts of both countries were taken from regional statistics. The P(C4 pattern within the 0.7 million km(2 sampling area was geostatistically analyzed and related to stocking rates and temperature gradients. For similar climatic conditions, P(C4 was the same in both countries. Further, a unique relationship was found between P(C4 and July temperature on both sides of the border, which explained 71% of the pattern. Stocking rate and grazing system had no significant influences on present-day C(3/C(4 abundance ratio. This finding suggests that recent changes in the C(3/C(4 ratio of these grasslands are mainly a consequence of regional warming, not overgrazing.

  1. Evidence for a toroidal magnetic-field component in 5C 4.114 on kiloparsec scales

    Science.gov (United States)

    Gabuzda, Denise C.; Knuettel, Sebastian; Bonafede, Annalisa

    2015-11-01

    Context. A monotonic, statistically significant gradient in the observed Faraday rotation measure (RM) across the jet of an active galactic nucleus (AGN) reflects a corresponding gradient in the electron density and/or line-of-sight magnetic (B) field in the region of Faraday rotation. For this reason, such gradients may indicate the presence of a toroidal B field component, possibly associated with a helical jet B field. Although transverse RM gradients have been reported across a number of parsec-scale AGN jets, the same is not true on kiloparsec scales, suggesting that other (e.g. random) magnetic-field components usually dominate on these larger scales. Aims: We wished to identify clear candidates for monotonic, transverse RM gradients across AGN jet and lobe structures on scales larger than those probed thus far, and estimate their statistical significances. Methods: We identified an extended, monotonic transverse Faraday-rotation gradient across the northern lobe of a previously published Very Large Array (kiloparsec-scale) RM image of 5C 4.114. We reanalyzed these VLA data in order to determine the significance of this RM gradient. Results: The RM gradient across the northern kiloparsec-scale lobe structure of 5C 4.114 has a statistical significance of about 4σ. There is also a somewhat less prominent monotonic transverse Faraday-rotation gradient across the southern jet/lobe (narrower range of distances from the core, significance ≃ 3σ). Other parts of the Faraday-rotation distribution observed across the source are patchy and show no obvious order. Conclusions: This suggests that we are observing a random RM component associated with the foreground material in the cluster in which the radio source is located and through which it is viewed, superposed on a more ordered RM component that arises in the immediate vicinity of the AGN jets. We interpret the transverse RM gradient as reflecting the systematic variations of the line-of-sight component of a

  2. Conserved patterns hidden within group A Streptococcus M protein hypervariability are responsible for recognition of human C4b-binding protein

    Science.gov (United States)

    Buffalo, Cosmo Z.; Bahn-Suh, Adrian J.; Hirakis, Sophia P.; Biswas, Tapan; Amaro, Rommie E.; Nizet, Victor; Ghosh, Partho

    2016-01-01

    No vaccine exists against group A Streptococcus (GAS), a leading cause of worldwide morbidity and mortality. A severe hurdle is the hypervariability of its major antigen, the M protein, with >200 different M types known. Neutralizing antibodies typically recognize M protein hypervariable regions (HVRs) and confer narrow protection. In stark contrast, human C4b-binding protein (C4BP), which is recruited to the GAS surface to block phagocytic killing, interacts with a remarkably large number of M protein HVRs (apparently ~90%). Such broad recognition is rare, and we discovered a unique mechanism for this through structure determination of four sequence-diverse M proteins in complex with C4BP. The structures revealed a uniform and tolerant ‘reading head’ in C4BP, which detected conserved sequence patterns hidden within hypervariability. Our results open up possibilities for rational therapies targeting the M-C4BP interaction, and also inform a path towards vaccine design. PMID:27595425

  3. Charge Exchange in Low-Energy H, D + C4+ Collisions with Full Account of Electron Translation

    Directory of Open Access Journals (Sweden)

    N. Vaeck

    2002-03-01

    Full Text Available We report the application of the quantum approach, which takes full account of electron translation at low collisional energies, to the charge exchange process H, D + C4+ → H+, D+ + C3+(3s; 3p; 3d. The partial and the total integral cross sections of the process are calculated in the energy range from 1 till 60 eV/amu. It is shown that the present results are independent from the upper integration limit for numerical solution of the coupled channel equations although nonadiabatic couplings remain nonzero up to infinity. The calculated partial and total cross sections are in agreement with the previous low-energy calculations and the available experimental data. It is shown that for low collisional energies the isotopic effect takes place. The observed effect is explained in terms of the nonadiabatic dynamics.

  4. A Diels-Alder super diene breaking benzene into C2H2 and C4H4 units

    Science.gov (United States)

    Inagaki, Yusuke; Nakamoto, Masaaki; Sekiguchi, Akira

    2014-01-01

    Cyclic polyene with six carbon atoms (benzene) is very stable, whereas cyclic polyene with four carbon atoms (cyclobutadiene) is extremely unstable. The electron-withdrawing pentafluorophenyl group of a substituted cyclobutadiene lowers the energy of the lowest unoccupied molecular orbital, greatly increasing its reactivity as a diene in Diels-Alder reactions with acetylene, ethylene and even benzene. Here we show that the reaction with benzene occurs cleanly at the relatively low temperature of 120 °C and results in the formal fragmentation of benzene into C2H2 and C4H4 units, via a unique Diels-Alder/retro-Diels-Alder reaction. This is a new example of the rare case where breaking the C-C bond of benzene is possible with no activation by a transition metal.

  5. Population dynamics and genetic diversity of C4 strains of human enterovirus 71 in Mainland China, 1998-2010.

    Directory of Open Access Journals (Sweden)

    Dawei Guan

    Full Text Available BACKGROUND: Since 1997, several countries within the Asian Pacific region have been affected by one or more massive outbreaks of Hand Foot and Mouth Disease (HFMD. Virus typing experiments revealed that these outbreaks were caused by strains of human enterovirus 71 (EV71 belonging to several different, recently emerged subgenogroups. In mainland China, a different situation was observed. The first outbreak, localized in Shangdong Province, was reported in 2007, and was followed by a wide-spread outbreak in mainland China in 2008. Since then, numbers of reported HFMD cases have been persistently high. METHODOLOGY/PRINCIPAL FINDINGS: To gain insight in the epidemiological behavior of EV71 in China, we studied genetic diversity and EV71 population dynamics to address whether the increase in number of reported EV71 infections reflects a real increase in viral spread or is just the result of increased awareness and surveillance. We used systematically collected VP1 gene sequences of 257 EV71 strains collected in Guangdong province from 2008 to 2010 as part of HFMD surveillance activities, and supplemented them with 305 GenBank EV71 reference stains collected in China from 1998 to 2010. All isolates from Guangdong Province belonged to subgenogroup C4. Viral population dynamics indicated that the increased reporting of HFMD in China since 2007 reflects a real increase in viral spread and continued replacement of viral lineages through time. Amino acid sequence comparisons revealed substitution of amino acid in residues 22, 145 and 289 through time regularly with the VP1 gene of EV71 strains isolated in mainland China from 1998 to 2010. CONCLUSIONS: EV71 strains isolated in mainland China mainly belonged to subgenogroup C4. There was exponential growth of the EV71 virus population in 2007 and 2008. There was amino acid substitution through time regularly with the VP1 gene which possibly increased viral spread and/or ability of the virus to circulate

  6. Interaction of leukotriene C4 and Chinese hamster lung fibroblasts (V79A03 cells). 1. Characterization of binding.

    Science.gov (United States)

    Fitz, T A; Contois, D F; Liu, Y X; Watt, D S; Walden, T L

    1990-10-01

    A novel, specific, and potent biological action of leukotriene C4 (LTC4) was demonstrated in the Chinese hamster lung fibroblast cell line V79A03 (V79 cells), namely the confirment of protection against subsequent gamma-irradiation. Consequently, studies were conducted to determine whether LTC4-conferred radioprotection could be attributed to a receptor-mediated phenomenon. Specific binding sites for leukotriene C4 (LTC4) were identified and characterized using intact V79 cells incubated at 4 degrees C in the presence of serine-borate, during which time conversion of LTC4 to LTD4 or LTE4 was undetectable. Binding was maximal in a broad region between pH 6.2 and 8.8. Ca2+, Mg2+, and Na+ were not required for binding, and binding was not altered by GTP, ATP, or cAMP, by leukotrienes B4, D4, or E4, or by the leukotriene end point antagonists LY 171883, FPL 55712, or Revlon 5901-5. Scatchard analyses and kinetic experiments indicated the presence of high-affinity [Kd = 2.5 +/- 0.63 nM, approximately 9.9 x 10(5) sites/cell] and low-affinity [Kd = 350 +/- 211 nM, approximately 2.7 x 10(6) sites/cell] binding sites. The observed binding characteristics of LTC4 to V79 cells are consistent with a receptor-mediated phenomenon. In a companion communication which follows this report, we report the subcellular distribution of LTC4 binding to V79 cells and demonstrate that this binding is unlikely to be attributed principally to interaction with glutathione-S-transferase.

  7. Structural Analysis of Streptococcus pyogenes NADH Oxidase: Conformational Dynamics Involved in Formation of the C(4a)-Peroxyflavin Intermediate.

    Science.gov (United States)

    Wallen, Jamie R; Mallett, T Conn; Okuno, Takashi; Parsonage, Derek; Sakai, Hiroaki; Tsukihara, Tomitake; Claiborne, Al

    2015-11-17

    In probing the oxygen reactivity of an Enterococcus faecalis NADH oxidase (Nox; O2 → 2H2O) C42S mutant lacking the Cys42-sulfenic acid (Cys42-SOH) redox center, we provided direct evidence of a C(4a)-peroxyflavin intermediate in the oxidative half-reaction and also described a conformational or chemical change that is rate-limiting for full reoxidation of the homodimer. In this work, the Nox from Streptococcus pyogenes (SpyNox) has been expressed and crystallized, and the overoxidized wild-type [Cys44-SOH → Cys44-sulfinic acid (Cys44-SO2H)] and C44S mutant enzyme structures have been refined at 2.0 and 2.15 Å, respectively. We show that azide binds to the two-electron reduced wild-type (EH2) enzyme and to the mutant enzyme in solution, but with a significantly higher affinity for the mutant protein. The spectral course of the titration with the SpyNox EH2 form clearly indicates progressive displacement of the Cys44-S(-) → FAD charge-transfer interaction. An azide soak with C44S Nox crystals led to the structure of the complex, as refined at 2.10 Å. The active-site N3(-) ligand is proximal to the Ser44 and His11 side chains, and a significant shift in the Ser44 side chain also appears. This provides an attractive explanation for the azide-induced loss of charge-transfer absorbance seen with the wild-type EH2 form and also permits accommodation of a C(4a)-peroxyflavin structural model. The conformation of Ser44 and the associated helical element, and the resulting steric accommodation, appear to be linked to the conformational change described in the E. faecalis C42S Nox oxidative half-reaction.

  8. Stable carbon isotope analysis of fluvial sediment fluxes over two contrasting C(4) -C(3) semi-arid vegetation transitions.

    Science.gov (United States)

    Puttock, Alan; Dungait, Jennifer A J; Bol, Roland; Dixon, Elizabeth R; Macleod, Christopher J A; Brazier, Richard E

    2012-10-30

    Globally, many drylands are experiencing the encroachment of woody vegetation into grasslands. These changes in ecosystem structure and processes can result in increased sediment and nutrient fluxes due to fluvial erosion. As these changes are often accompanied by a shift from C(4) to C(3) vegetation with characteristic δ(13) C values, stable isotope analysis provides a promising mechanism for tracing these fluxes. Input vegetation, surface sediment and fluvially eroded sediment samples were collected across two contrasting C(4) -C(3) dryland vegetation transitions in New Mexico, USA. Isotope ratio mass spectrometric analyses were performed using a Carlo Erba NA2000 analyser interfaced to a SerCon 20-22 isotope ratio mass spectrometer to determine bulk δ(13) C values. Stable isotope analyses of contemporary input vegetation and surface sediments over the monitored transitions showed significant differences (p Pinus edulis/Juniperus monosperma (piñon-juniper) woodland sites. Significantly, this distinctive δ(13) C value was maintained in the bulk δ(13) C values of fluvially eroded sediment from each of the sites, with no significant variation between surface sediment and eroded sediment values. The significant differences in bulk δ(13) C values between sites were dependent on vegetation input. Importantly, these values were robustly expressed in fluvially eroded sediments, suggesting that stable isotope analysis is suitable for tracing sediment fluxes. Due to the prevalent nature of these dryland vegetation transitions in the USA and globally, further development of stable isotope ratio mass spectrometry has provided a valuable tool for enhanced understanding of functional changes in these ecosystems. Copyright © 2012 John Wiley & Sons, Ltd.

  9. Endangered Species

    Science.gov (United States)

    EPA's Endangered Species Protection Program helps promote recovery of listed species. The ESPP determines if pesticide use in a geographic area may affect any listed species. Find needed limits on pesticide use in Endangered Species Protection Bulletins.

  10. C4b binding protein binds to CD154 preventing CD40 mediated cholangiocyte apoptosis: a novel link between complement and epithelial cell survival.

    Directory of Open Access Journals (Sweden)

    Kevin T Williams

    Full Text Available Activation of CD40 on hepatocytes and cholangiocytes is critical for amplifying Fas-mediated apoptosis in the human liver. C4b-Binding Protein (C4BP has been reported to act as a potential surrogate ligand for CD40, suggesting that it could be involved in modulating liver epithelial cell survival. Using surface plasmon resonance (BiaCore analysis supported by gel filtration we have shown that C4BP does not bind CD40, but it forms stable high molecular weight complexes with soluble CD40 ligand (sCD154. These C4BP/sCD154 complexes bound efficiently to immobilised CD40, but when applied to cholangiocytes they failed to induce apoptosis or proliferation or to activate NFkB, AP-1 or STAT 3, which are activated by sCD154 alone. Thus C4BP can modulate CD40/sCD154 interactions by presenting a high molecular weight multimeric sCD154/C4BP complex that suppresses critical intracellular signalling pathways, permitting cell survival without inducing proliferation. Immunohistochemistry demonstrated co-localisation and enhanced expression of C4BP and CD40 in human liver cancers. These findings suggest a novel pathway whereby components of the complement system and TNF ligands and receptors might be involved in modulating epithelial cell survival in chronic inflammation and malignant disease.

  11. C4'/H4' selective, non-uniformly sampled 4D HC(P)CH experiment for sequential assignments of (13)C-labeled RNAs.

    Science.gov (United States)

    Saxena, Saurabh; Stanek, Jan; Cevec, Mirko; Plavec, Janez; Koźmiński, Wiktor

    2014-11-01

    A through bond, C4'/H4' selective, "out and stay" type 4D HC(P)CH experiment is introduced which provides sequential connectivity via H4'(i)-C4'(i)-C4'(i-1)-H4'(i-1) correlations. The (31)P dimension (used in the conventional 3D HCP experiment) is replaced with evolution of better dispersed C4' dimension. The experiment fully utilizes (13)C-labeling of RNA by inclusion of two C4' evolution periods. An additional evolution of H4' is included to further enhance peak resolution. Band selective (13)C inversion pulses are used to achieve selectivity and prevent signal dephasing due to the of C4'-C3' and C4'-C5' homonuclear couplings. For reasonable resolution, non-uniform sampling is employed in all indirect dimensions. To reduce sensitivity losses, multiple quantum coherences are preserved during shared-time evolution and coherence transfer delays. In the experiment the intra-nucleotide peaks are suppressed whereas inter-nucleotide peaks are enhanced to reduce the ambiguities. The performance of the experiment is verified on a fully (13)C, (15)N-labeled 34-nt hairpin RNA comprising typical structure elements.

  12. Altered expression of the urokinase receptor homologue, C4.4A, in invasive areas of human esophageal squamous cell carcinoma

    DEFF Research Database (Denmark)

    Hansen, L.V.; Laerum, O.D.; Illemann, M.

    2008-01-01

    C4.4A is a glycolipid-anchored membrane protein with structural homology to the urokinase-type plasminogen activator receptor (uPAR). Although C4.4A was identified as a metastasis-associated protein little is known about its actual expression and possible function in malignant disease. In the pre......C4.4A is a glycolipid-anchored membrane protein with structural homology to the urokinase-type plasminogen activator receptor (uPAR). Although C4.4A was identified as a metastasis-associated protein little is known about its actual expression and possible function in malignant disease....... In the present study, we have therefore analyzed the expression of C4.4A in 14 esophageal squamous cell carcinomas (ESCC). Normal squamous esophageal epithelium shows a strong cell surface associated C4.4A expression in the suprabasal layers, whereas basal cells are negative. Upon transition to dysplasia......, we analyzed the possible coexpression of C4.4A and the gamma 2-chain of LN5 (LN5-gamma 2). Although these proteins are indeed expressed by either neighboring cancer cells or in a few cases even coexpressed by the same cells in the tumor front and metastases, we found no evidence for a general...

  13. Fumarate and cytosolic pH as modulators of the synthesis or consumption of C(4) organic acids through NADP-malic enzyme in Arabidopsis thaliana.

    Science.gov (United States)

    Arias, Cintia Lucía; Andreo, Carlos Santiago; Drincovich, María Fabiana; Gerrard Wheeler, Mariel Claudia

    2013-02-01

    Arabidopsis thaliana is a plant species that accumulates high levels of organic acids and uses them as carbon, energy and reducing power sources. Among the enzymes that metabolize these compounds, one of the most important ones is malic enzyme (ME). A. thaliana contains four malic enzymes (NADP-ME 1-4) to catalyze the reversible oxidative decarboxylation of malate in the presence of NADP. NADP-ME2 is the only one located in the cell cytosol of all Arabidopsis organs providing most of the total NADP-ME activity. In the present work, the regulation of this key enzyme by fumarate was investigated by kinetic assays, structural analysis and a site-directed mutagenesis approach. The final effect of this metabolite on NADP-ME2 forward activity not only depends on fumarate and substrate concentrations but also on the pH of the reaction medium. Fumarate produced an increase in NADP-ME2 activity by binding to an allosteric site. However at higher concentrations, fumarate caused a competitive inhibition, excluding the substrate malate from binding to the active site. The characterization of ME2-R115A mutant, which is not activated by fumarate, confirms this hypothesis. In addition, the reverse reaction (reductive carboxylation of pyruvate) is also modulated by fumarate, but in a different way. The results indicate pH-dependence of the fumarate modulation with opposite behavior on the two activities analyzed. Thereby, the coordinated action of fumarate over the direct and reverse reactions would allow a precise and specific modulation of the metabolic flux through this enzyme, leading to the synthesis or degradation of C(4) compounds under certain conditions. Thus, the physiological context might be exerting an accurate control of ME activity in planta, through changes in metabolite and substrate concentrations and cytosolic pH.

  14. Method for Walking Gait Identification in a Lower Extremity Exoskeleton Based on C4.5 Decision Tree Algorithm

    Directory of Open Access Journals (Sweden)

    Qing Guo

    2015-04-01

    Full Text Available A gait identification method for a lower extremity exoskeleton is presented in order to identify the gait sub-phases in human-machine coordinated motion. First, a sensor layout for the exoskeleton is introduced. Taking the difference between human lower limb motion and human-machine coordinated motion into account, the walking gait is divided into five sub-phases, which are ‘double standing’, ‘right leg swing and left leg stance’, ‘double stance with right leg front and left leg back’, ‘right leg stance and left leg swing’, and ‘double stance with left leg front and right leg back’. The sensors include shoe pressure sensors, knee encoders, and thigh and calf gyroscopes, and are used to measure the contact force of the foot, and the knee joint angle and its angular velocity. Then, five sub-phases of walking gait are identified by a C4.5 decision tree algorithm according to the data fusion of the sensors' information. Based on the simulation results for the gait division, identification accuracy can be guaranteed by the proposed algorithm. Through the exoskeleton control experiment, a division of five sub-phases for the human-machine coordinated walk is proposed. The experimental results verify this gait division and identification method. They can make hydraulic cylinders retract ahead of time and improve the maximal walking velocity when the exoskeleton follows the person's motion.

  15. Phytoremediation of carbamazepine and its metabolite 10,11-epoxycarbamazepine by C3 and C4 plants.

    Science.gov (United States)

    Ryšlavá, Helena; Pomeislová, Alice; Pšondrová, Šárka; Hýsková, Veronika; Smrček, Stanislav

    2015-12-01

    The anticonvulsant drug carbamazepine is considered as an indicator of sewage water pollution: however, its uptake by plants and effect on metabolism have not been sufficiently documented, let alone its metabolite (10,11-epoxycarbamazepine). In a model system of sterile, hydroponically cultivated Zea mays (as C4 plant) and Helianthus annuus (as C3 plant), the uptake and effect of carbamazepine and 10,11-epoxycarbamazepine were studied in comparison with those of acetaminophen and ibuprofen. Ibuprofen and acetaminophen were effectively extracted from drug-supplemented media by both plants, while the uptake of more hydrophobic carbamazepine was much lower. On the other hand, the carbamazepine metabolite, 10,11-epoxycarbamazepine, was, unlike sunflower, willingly taken up by maize plants (after 96 h 88 % of the initial concentration) and effectively stored in maize tissues. In addition, the effect of the studied pharmaceuticals on the plant metabolism (enzymes of Hatch-Slack cycle, peroxidases) was followed. The activity of bound peroxidases, which could cause xylem vessel lignification and reduction of xenobiotic uptake, was at the level of control plants in maize leaves contrary to sunflower. Therefore, our results indicate that maize has the potential to remove 10,11-epoxycarbamazepine from contaminated soils.

  16. Tier-scalable reconnaissance: the future in autonomous C4ISR systems has arrived: progress towards an outdoor testbed

    Science.gov (United States)

    Fink, Wolfgang; Brooks, Alexander J.-W.; Tarbell, Mark A.; Dohm, James M.

    2017-05-01

    Autonomous reconnaissance missions are called for in extreme environments, as well as in potentially hazardous (e.g., the theatre, disaster-stricken areas, etc.) or inaccessible operational areas (e.g., planetary surfaces, space). Such future missions will require increasing degrees of operational autonomy, especially when following up on transient events. Operational autonomy encompasses: (1) Automatic characterization of operational areas from different vantages (i.e., spaceborne, airborne, surface, subsurface); (2) automatic sensor deployment and data gathering; (3) automatic feature extraction including anomaly detection and region-of-interest identification; (4) automatic target prediction and prioritization; (5) and subsequent automatic (re-)deployment and navigation of robotic agents. This paper reports on progress towards several aspects of autonomous C4ISR systems, including: Caltech-patented and NASA award-winning multi-tiered mission paradigm, robotic platform development (air, ground, water-based), robotic behavior motifs as the building blocks for autonomous tele-commanding, and autonomous decision making based on a Caltech-patented framework comprising sensor-data-fusion (feature-vectors), anomaly detection (clustering and principal component analysis), and target prioritization (hypothetical probing).

  17. The Raman Spectrum of the Squarate (C4O4-2 Anion: An Ab Initio Basis Set Dependence Study

    Directory of Open Access Journals (Sweden)

    Miranda Sandro G. de

    2002-01-01

    Full Text Available The Raman excitation profile of the squarate anion, C4O4-2 , was calculated using ab initio methods at the Hartree-Fock using Linear Response Theory (LRT for six excitation frequencies: 632.5, 514.5, 488.0, 457.9, 363.8 and 337.1 nm. Five basis set functions (6-31G*, 6-31+G*, cc-pVDZ, aug-cc-pVDZ and Sadlej's polarizability basis set were investigated aiming to evaluate the performance of the 6-31G* set for numerical convergence and computational cost in relation to the larger basis sets. All basis sets reproduce the main spectroscopic features of the Raman spectrum of this anion for the excitation interval investigated. The 6-31G* basis set presented, on average, the same accuracy of numerical results as the larger sets but at a fraction of the computational cost showing that it is suitable for the theoretical investigation of the squarate dianion and its complexes and derivatives.

  18. The development of novel Nexar block copolymer/Ultem composite membranes for C2-C4 alcohols dehydration via pervaporation.

    Science.gov (United States)

    Zuo, Jian; Shi, Gui Min; Wei, Shawn; Chung, Tai-Shung

    2014-08-27

    Novel composite membranes comprising sulfonated styrenic Nexar pentablock copolymers were developed by dip-coating on poly(ether imide) hollow fibers for pervaporation dehydration of C2-C4 alcohols. The advantages of using block copolymers as the selective layer are (1) their effectiveness to synergize the physicochemical properties of different chemical and structural moieties and (2) tunable nanoscale morphology and nanostructure via molecular engineering. To achieve high-performance composite membranes, the effects of coating time, ion exchange capacity (IEC) of the copolymer, and solvent systems for coating were investigated. It is revealed that a minimum coating time of 30 s is needed for the formation of a continuous and less-defective top layer. A higher IEC value results in a membrane with a higher flux and lower separation factor because of enhanced hydrophilicity and stretched chain conformation. Moreover, the composite membranes prepared from hexane/ethanol mixtures show higher separation factors and lower fluxes than those from the hexane solvent owing to microdomain segregation induced by ethanol and a smooth and dense top selective layer. These hypotheses were verified by atomic force microscopy and positron annihilation spectroscopy. The newly developed composite membranes demonstrate impressive separation performance with fluxes exceeding 2 kg/m(2) h and separation factors more than 200 for isopropyl alcohol and n-butanol dehydration from 85/15 wt % alcohol/water feed mixtures at 50 °C.

  19. C4N3H monolayer: A two-dimensional organic Dirac material with high Fermi velocity

    Science.gov (United States)

    Pan, Hongzhe; Zhang, Hongyu; Sun, Yuanyuan; Li, Jianfu; Du, Youwei; Tang, Nujiang

    2017-11-01

    Searching for two-dimensional (2D) organic Dirac materials, which have more adaptable practical applications compared with inorganic ones, is of great significance and has been ongoing. However, only two such materials with low Fermi velocity have been discovered so far. Herein, we report the design of an organic monolayer with C4N3H stoichiometry that possesses fascinating structure and good stability in its free-standing state. More importantly, we demonstrate that this monolayer is a semimetal with anisotropic Dirac cones and very high Fermi velocity. This Fermi velocity is roughly one order of magnitude larger than the largest velocity ever reported in 2D organic Dirac materials, and it is comparable to that in graphene. The Dirac states in this monolayer arise from the extended π -electron conjugation system formed by the overlapping 2 pz orbitals of carbon and nitrogen atoms. Our finding paves the way to a search for more 2D organic Dirac materials with high Fermi velocity.

  20. PPARγ regulates expression of carbohydrate sulfotransferase 11 (CHST11/C4ST1, a regulator of LPL cell surface binding.

    Directory of Open Access Journals (Sweden)

    Ismayil Tasdelen

    Full Text Available The transcription factor PPARγ is the key regulator of adipocyte differentiation, function and maintenance, and the cellular target of the insulin-sensitizing thiazolidinediones. Identification and functional characterization of genes regulated by PPARγ will therefore lead to a better understanding of adipocyte biology and may also contribute to the development of new anti-diabetic drugs. Here, we report carbohydrate sulfotransferase 11 (Chst11/C4st1 as a novel PPARγ target gene. Chst11 can sulphate chondroitin, a major glycosaminoglycan involved in development and disease. The Chst11 gene contains two functional intronic PPARγ binding sites, and is up-regulated at the mRNA and protein level during 3T3-L1 adipogenesis. Chst11 knockdown reduced intracellular lipid accumulation in mature adipocytes, which is due to a lowered activity of lipoprotein lipase, which may associate with the adipocyte cell surface through Chst11-mediated sulfation of chondroitin, rather than impaired adipogenesis. Besides directly inducing Lpl expression, PPARγ may therefore control lipid accumulation by elevating the levels of Chst11-mediated proteoglycan sulfation and thereby increasing the binding capacity for Lpl on the adipocyte cell surface.

  1. Emergency Closed Reduction of a C4/5 Fracture Dislocation with Complete Paraplegia Resulting in Profound Neurologic Recovery

    Directory of Open Access Journals (Sweden)

    Christian W. Müller

    2013-01-01

    Full Text Available Introduction. Cervical spinal cord injuries due to traumatic fractures are associated with persistent neurological deficits. Although clinical evidence is weak, early decompression, defined as <24–72 h, has been frequently proposed. Animal studies show better outcomes after early decompression within one hour or less, which can hardly ever be achieved in clinical practice. Case Presentation. A 37-year-old patient was hospitalized after being hit by a shying horse. After diagnosis of C4/5 fracture dislocation and complete paraplegia, she was intubated and sedated with deep relaxation. Emergency reduction was performed at approximately 120 minutes after trauma. Subsequently, a standard anterior decompression, discectomy, and fusion were carried out. She was then transferred to a specialized rehabilitation hospital. Her neurologic function improved from AIS grade A on admission to grade B postoperatively and grade D after four months of rehabilitation. One year after the accident, she was ambulatory without walking aids and restarted horse riding. Discussion and Conclusion. Rarely in clinical practice, decompression of the spine canal can be performed as early as in this case. This case highlights the potential benefit of utmost early reduction in cervical fracture dislocations with compression of the spinal cord.

  2. S-oxidation of thiazolidinedione with hydrogen peroxide, peroxynitrous acid, and C4a-hydroperoxyflavin: a theoretical study.

    Science.gov (United States)

    Taxak, Nikhil; Parmar, Vinod; Patel, Dhilon S; Kotasthane, Anuja; Bharatam, Prasad V

    2011-02-10

    Quantum chemical analysis was carried out to model metabolism of glitazone class of drugs through oxygen transfer process to the sulfur atom of thiazolidinedione ring with different oxidants such as H(2)O(2), HOONO, and C4a-hydroperoxyflavin. Complete optimization (geometric and energy parameters) of all the required structures and transition states on the reaction path was carried out using MP2(full)/6-31+G(d,p). Charge and second-order delocalization analyses of important structures were carried out using the NBO method. The effect of solvent on the oxygen transfer to sulfur of thiazolidinedione was studied by including one, two, or three explicit water molecules. These calculations revealed that explicit solvent (water) effectively contributed in the sulfoxidation of thiazolidinedione and led to remarkable reduction in the energy barrier by ∼10 kcal/mol as compared to the gas phase. These results were found to be consistent with previously reported S-oxidation of dimethyl sulfide. When explicit water molecules were included, solvent molecules stabilize the charge separation at the transition state via specific interactions, and oxidation occurs via stretching of the O-O bond of oxidants and gradual formation of S-O bond. This study is helpful in understanding the metabolite generation due to the S-oxidation process in the glitazone series of antidiabetic drugs under physiological conditions.

  3. Pasteurella pneumotropica evades the human complement system by acquisition of the complement regulators factor H and C4BP.

    Directory of Open Access Journals (Sweden)

    Alfredo Sahagún-Ruiz

    Full Text Available Pasteurella pneumotropica is an opportunist Gram negative bacterium responsible for rodent pasteurellosis that affects upper respiratory, reproductive and digestive tracts of mammals. In animal care facilities the presence of P. pneumotropica causes severe to lethal infection in immunodeficient mice, being also a potential source for human contamination. Indeed, occupational exposure is one of the main causes of human infection by P. pneumotropica. The clinical presentation of the disease includes subcutaneous abscesses, respiratory tract colonization and systemic infections. Given the ability of P. pneumotropica to fully disseminate in the organism, it is quite relevant to study the role of the complement system to control the infection as well as the possible evasion mechanisms involved in bacterial survival. Here, we show for the first time that P. pneumotropica is able to survive the bactericidal activity of the human complement system. We observed that host regulatory complement C4BP and Factor H bind to the surface of P. pneumotropica, controlling the activation pathways regulating the formation and maintenance of C3-convertases. These results show that P. pneumotropica has evolved mechanisms to evade the human complement system that may increase the efficiency by which this pathogen is able to gain access to and colonize inner tissues where it may cause severe infections.

  4. Does total disc arthroplasty in C3/C4-segments change the kinematic features of axial rotation?

    Science.gov (United States)

    Wachowski, Martin Michael; Wagner, Markus; Weiland, Jan; Dörner, Jochen; Raab, Björn Werner; Dathe, Henning; Gezzi, Riccardo; Kubein-Meesenburg, Dietmar; Nägerl, Hans

    2013-06-21

    We analyze how kinematic properties of C3/C4-segments are modified after total disc arthroplasty (TDA) with PRESTIGE(®) and BRYAN(®) Cervical Discs. The measurements were focused on small ranges of axial rotation (TDA. External parameters: constant axially directed pre-load, constant flexional/extensional and lateral-flexional pre-torque. The applied axial torque and IHA-direction did not run parallel. The IHA-direction was found to be rotated backwards and largely independent of the rotational angle, amount of axial pre-load, size of pre-torque, and TDA. In the intact segments pre-flexion/extension hardly influenced IHA-positions. After TDA, IHA-position was shifted backwards significantly (BRYAN-TDA: ≈8mm; PRESTIGE-TDA: ≈6mm) and in some segments laterally as well. Furthermore it was significantly shifted ventrally by pre-flexion and dorsally by pre-extension. The rate of lateral IHA-migration increased significantly after BRYAN-TDA during rightward or leftward rotations. In conclusion after the TDA the IHA-positions shifted backwards with significant increase in variability of the IHA-positions after the BRYAN-TDA more than in PRESTIGE-TDA. The TDA-procedure altered the segment kinematics considerably. TDA causes additional translations of the vertebrae, which superimpose the kinematics of the adjacent levels. The occurrence of adjacent level disease (ALD) is not excluded after the TDA for kinematical reasons. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Frustration-driven C4symmetric order in a naturally-heterostructured superconductor Sr2VO3FeAs.

    Science.gov (United States)

    Ok, Jong Mok; Baek, S-H; Hoch, C; Kremer, R K; Park, S Y; Ji, Sungdae; Büchner, B; Park, J-H; Hyun, S I; Shim, J H; Bang, Yunkyu; Moon, E G; Mazin, I I; Kim, Jun Sung

    2017-12-18

    A subtle balance between competing interactions in iron-based superconductors (FeSCs) can be tipped by additional interfacial interactions in a heterostructure, often inducing exotic phases with unprecedented properties. Particularly when the proximity-coupled layer is magnetically active, rich phase diagrams are expected in FeSCs, but this has not been explored yet. Here, using high-accuracy 75 As and 51 V nuclear magnetic resonance measurements, we investigate an electronic phase that emerges in the FeAs layer below T 0  ~ 155 K of Sr 2 VO 3 FeAs, a naturally assembled heterostructure of an FeSC and a Mott-insulating vanadium oxide. We find that frustration of the otherwise dominant Fe stripe and V Neel fluctuations via interfacial coupling induces a charge/orbital order in the FeAs layers, without either static magnetism or broken C 4 symmetry, while suppressing the Neel antiferromagnetism in the SrVO 3 layers. These findings demonstrate that the magnetic proximity coupling stabilizes a hidden order in FeSCs, which may also apply to other strongly correlated heterostructures.

  6. Dominant amino acids, organic acids and sugars in water-soluble root exudates of C4 plants: a mini-review

    Directory of Open Access Journals (Sweden)

    Valerie Vranová

    2010-01-01

    Full Text Available The aim of this mini-review was to identify the dominant carbohydrates, organic acids and amino ­acids in water-soluble root exudates of plants which represent dominant compounds there. The study is focused on plants of C4-type of metabolism taking into account available literature. From group of carbohydrates, those dominant are represented glucose, fructose, arabinose and sucrose. Between dominant amino acids occurring in root exudates of C4-metabolism plants are alanine, se­rine, arginine, glutamine, glutamic and aspartic acid, glycine, proline, cystine, lysine and g-aminobutyric acid. Citric, malic, tartaric, succinic, trans-aconitic represent the dominant organic acids. This knowledge may be useful for planning analyses of these compounds in root exudates of C4 plants. Except for this preparation of synthetic root exudates to simulate rhizosphere of C4 plants may be performed based on these results.

  7. Integration of Two SPAWAR PEOC4I NetCentric Technologies: Tactical Environmental Database Services (TEDServices) with the Extensible Tactical C4I Framework (XTCF)

    National Research Council Canada - National Science Library

    Bowers, Timothy H

    2007-01-01

    .... This was accomplished by delivering current weather data from Tactical Environmental Data Services (TEDServices), an API used to request meterological, oceanographic, and environmental information, through the Extensible Tactical C4I Framework...

  8. Paleontology and stratigraphy of the Upper Triassic Kamishak Formation in the Puale Bay-Cape Kekurnoi-Alinchak Bay area, Karluk C-4 and C-5 quadrangle

    Data.gov (United States)

    Department of the Interior — This report summarizes the paleontological character and stratigraphy of the Kamishak Formation in the Puale Bay–Cape Kekurnoi–Alinchak Bay area, Karluk C-4 and C-5...

  9. Solution Structures of Complement C2 and its C4 Complexes Propose Pathway Specific Mechanisms for Control and Activation of the Complement Proconvertases

    DEFF Research Database (Denmark)

    Mortensen, Sofia; Jensen, Jan Kristian; Andersen, Gregers Rom

    2016-01-01

    The lectin (LP) and classical (CP) pathways are two of the three main activation cascades of the complement system. These pathways start with recognition of different pathogen- or danger-associated molecular patterns and include identical steps of proteolytic activation of complement component C4......, formation of the C3 proconvertase C4b2, followed by cleavage of complement component C2 within C4b2 resulting in the C3 convertase C4b2a. Here we describe the solution structures of the two central complexes of the pathways, C3 proconvertase and C3 convertase, as well as the unbound zymogen C2 obtained...... to the crystal structure of the AP C3 convertase C3bBb which is in accordance with their identical functions in cleaving the complement proteins C3 and C5....

  10. Using vegetation model-to-data comparisons to test the role of abiotic factors in the Neogene and Quaternary origins of modern C4 grasslands

    Science.gov (United States)

    Fox, D. L.; Strömberg, C.; Pau, S.; Taylor, L.; Lehmann, C.; Osborne, C.; Beerling, D. J.; Still, C. J.

    2014-12-01

    Grasslands dominated by taxa using the C4 photosynthetic pathway evolved on several continents during the Neogene and Quaternary, long after C4 photosynthesis first evolved among grasses. The histories of these ecosystems are relatively well documented in the geological record from stable carbon isotopes (fossil vertebrate herbivores, paleosols) and the plant microfossil record (pollen, phytoliths). The distinct biogeography and ecophysiology of modern C3 and C4 grasses have led to hypotheses explaining the origins of C4 grasslands in terms of long term changes in the Earth system such as increased aridity and decreasing atmospheric pCO2. However, proxies for key parameters of these hypotheses (e.g., temperature, precipitation, pCO2) are still in development, not yet widely applied, or remain contentious, so testing the hypotheses globally remains difficult. To understand better possible links between changes in the Earth system and the origin of C4 grasslands on different continents, we are undertaking a global scale comparison between observational records of C4 grass abundances in Miocene and Pliocene localities compiled from the literature, and three increasingly complex models of C4 dominance and abundance. The literature compilation comprises >2,600 δ13C values of both fossil vertebrates and of paleosol carbonates and >6,700 paleobotanical records. We are using paleoclimate output from the HadCM3L GCM over a range of pCO2 values for each epoch to model C4 dominance or abundance in grid cells as (Model 1) months per year exceeding the temperature at which net assimilation is greater for C4 than C3 photosynthesis (crossover temperature); (Model 2) the number of months per year exceeding the crossover temperature and having sufficient precipitation for growth (≥25 cm/yr; Collatz model); and (Model 3) the Sheffield Dynamic Global Vegetation Model (SDGVM), output from which includes biomass (g C/m2/yr) for distinct structural components (roots, stems, leaves

  11. A late-Quaternary perspective, on atmospheric pCO2, climate, and fire as drivers of C4-grass abundance.

    Science.gov (United States)

    Urban, Michael A; Nelson, David M; Street-Perrott, F Alayne; Verschuren, Dirk; Hul, Feng Sheng

    2015-03-01

    Various environmental factors, including atmospheric CO2 (pCO2), regional climate, and fire, have been invoked as primary drivers of long-term variation in C4 grass abundance. Evaluating these hypotheses has been difficult because available paleorecords often lack information on past C4 grass abundance or potential environmental drivers. We analyzed carbon isotope ratios (delta13C) of individual grains of grass pollen in the sediments of two East African lakes to infer changes in the relative abundance of C3 vs. C4 grasses during the past 25 000 years. Results were compared with concurrent changes in pCO2, temperature, moisture balance, and fire activity. Our grass-pollen delta13C analysis reveals a dynamic history of grass-dominated vegetation in equatorial East Africa: C4 grasses have not consistently dominated lowland areas, and high-elevation grasses have not always been predominantly C3. On millennial timescales, C4 grass abundance does not correlate with charcoal influx at either site, suggesting that fire was not a major proximate control of the competitive balance between C3 and C4 grasses. Above the present-day treeline on Mt. Kenya, C4 grass abundance declined from an average of approximately 90% during the glacial period to less than approximately 60% throughout the Holocene, coincident with increases in pCO2 and temperature, and shifts in moisture balance. In the lowland savanna southeast of Mt. Kilimanjaro, C4 grass abundance showed no such directional trend, but fluctuated markedly in association with variation in rainfall amount and seasonal-drought severity. These results underscore spatiotemporal variability in the relative influence of pCO2 and climate on the interplay of C3 and C4 grasses and shed light on an emerging conceptual model regarding the expansion of C4-dominated grasslands in Earth's history. They also suggest that future changes in the C3/C4 composition of grass-dominated ecosystems will likely exhibit striking spatiotemporal

  12. RP-UHPLC-UV-ESI-MS/MS analysis of LPMO generated C4-oxidized gluco-oligosaccharides after non-reductive labeling with 2-aminobenzamide

    OpenAIRE

    Frommhagen, Matthias; van Erven, Gijs; Sanders, Mark; van Berkel, Willem J. H.; Kabel, Mirjam A.; Gruppen, Harry

    2017-01-01

    Lytic polysaccharide monooxygenases (LPMOs) are able to cleave recalcitrant polysaccharides, such as cellulose, by oxidizing the C1 and/or C4 atoms. The analysis of the resulting products requires a variety of analytical techniques. Up to now, these techniques mainly focused on the identification of non-oxidized and C1-oxidized oligosaccharides. The analysis of C4-oxidized gluco-oligosaccharides is mostly performed by using high pressure anion exchange chromatography (HPAEC). However, the alk...

  13. Conserved patterns hidden within group A Streptococcus M protein hypervariability are responsible for recognition of human C4b-binding protein

    OpenAIRE

    Buffalo, Cosmo Z.; Bahn-Suh, Adrian J.; Sophia P Hirakis; Biswas, Tapan; Amaro, Rommie E.; Nizet, Victor; Ghosh, Partho

    2016-01-01

    No vaccine exists against group A Streptococcus (GAS), a leading cause of worldwide morbidity and mortality. A severe hurdle is the hypervariability of its major antigen, the M protein, with >200 different M types known. Neutralizing antibodies typically recognize M protein hypervariable regions (HVRs) and confer narrow protection. In stark contrast, human C4b-binding protein (C4BP), which is recruited to the GAS surface to block phagocytic killing, interacts with a remarkably large number of...

  14. C 3- und C 4-Photosynthese in Mais (Zea mays): das Hüllblatt der weiblichen Infloreszenz als Modellsystem zur Analyse photosynthetischer Genexpression

    OpenAIRE

    Hahnen, Silke

    2004-01-01

    C4 plants like maize adopt physiological and anatomical modifications for the establishment and maintenance of their type of photosynthesis. The regulation of these processes is mostly unknown. Within this study the ear of the female inflorescence of maize was established as a system for analysing C4-specific gene expression. This leaf like organ shows a clearly increased number of mesophyll cells in between the vascular bundles compared to foliar leaves. Only mesophyll cells in direct contac...

  15. Structural and biochemical characterization of the C3?C4 intermediate Brassica gravinae and relatives, with particular reference to cellular distribution of Rubisco

    OpenAIRE

    Ueno, Osamu

    2011-01-01

    On the basis of its CO2 compensation concentration, Brassica gravinae Ten. has been reported to be a C3?C4 intermediate. This study investigated the structural and biochemical features of photosynthetic metabolism in B. gravinae. The cellular distribution of ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) was also examined in B. gravinae, B. napus L. (C3), Raphanus sativus L. (C3), and Diplotaxis tenuifolia (L.) DC. (C3?C4) by immunogold electron microscopy to elucidate Rubisco expr...

  16. Ly6/uPAR-related protein C4.4A as a marker of solid growth pattern and poor prognosis in lung adenocarcinoma

    DEFF Research Database (Denmark)

    Jacobsen, Benedikte; Muley, Thomas; Meister, Michael

    2013-01-01

    We have recently shown that the protein C4.4A is induced in early precursor lesions of pulmonary adenocarcinomas and squamous cell carcinomas. In the present study, we aimed at analyzing the impact of C4.4A on the survival of non-small cell lung cancer patients and determining whether its...... unexpected expression in adenocarcinomas could be attributed to a specific growth type (lepidic, acinar, papillary, micropapillary, solid)....

  17. FJU-C4, a new 2-pyridone compound, attenuates lipopolysaccharide-induced systemic inflammation via p38MAPK and NF-κB in mice.

    Directory of Open Access Journals (Sweden)

    Jung-Sen Liu

    Full Text Available Despite advances in antibiotic therapy and intensive care, the mortality caused by systemic inflammatory response syndrome and severe sepsis remains high. The use of anti-inflammatory agents to attenuate inflammatory response during acute systemic inflammatory reactions may improve survival rates. Here we show that a newly synthesized 2-pyridone compound (FJU-C4 can suppress the expression of late inflammatory mediators such as iNOS and COX-2 in murine macrophages. The pro-inflammatory cytokines, including TNFα, IL-1β, and IL-6, were dose-dependently suppressed by FJU-C4 both in mRNA and protein levels. In addition, the expression of TNFα was inhibited from as early as 2 hours after exposure to LPS stimulation. The production of mature pro-inflammatory cytokines was also suppressed by pretreatment with FJU-C4 in either cell culture medium or mice serum when stimulated by LPS. FJU-C4 prolongs mouse survival and prevents mouse death from LPS-induced systemic inflammation when the dose of FJU-C4 is over 5 mg/kg. The activities of ERK, JNK, and p38MAPK were induced by LPS stimulation on murine macrophage cell line, but only p38MAPK signaling was dramatically suppressed by pretreatment with the FJU-C4 compound in a dose-dependent manner. NF-κB activation also was suppressed by FJU-C4 compound. These findings suggest that the FJU-C4 compound may act as a promising therapeutic agent against inflammatory diseases by inhibiting the p38MAPK and NF-κB signaling pathway.

  18. Carbon storage potential increases with increasing ratio of C4 to C3 grass cover and soil productivity in restored tallgrass prairies.

    Science.gov (United States)

    Spiesman, Brian J; Kummel, Herika; Jackson, Randall D

    2017-12-07

    Long-term soil carbon (C) storage is essential for reducing CO2 in the atmosphere. Converting unproductive and environmentally sensitive agricultural lands to grasslands for bioenergy production may enhance C storage. However, a better understanding of the interacting effects of grass functional composition (i.e., relative abundance of C4 and C3 grass cover) and soil productivity on C storage will help guide sustainable grassland management. Our objective was to examine the relationship between grass functional composition and potential C storage and how it varies with potential soil productivity. We estimated C inputs from above- and belowground net primary productivity (ANPP and BNPP), and heterotrophic respiration (R H) to calculate net ecosystem production (NEP), a measure of potential soil C storage, in grassland plots of relatively high- and low-productivity soils spanning a gradient in the ratio of C4 to C3 grass cover (C4:C3). NEP increased with increasing C4:C3, but only in potentially productive soils. The positive relationship likely stemmed from increased ANPP, rather than BNPP, which was possibly related to efficient resource-use and physiological/anatomical advantages of C4 plants. R H was negatively correlated with C4:C3, possibly because of changes in microclimate or plant-microbe interactions. It is possible that in potentially productive soils, C storage can be enhanced by favoring C4 over C3 grasses through increased ANPP and BNPP and reduced R H. Results also suggest that potential C storage gains from C4 productivity would not be undermined by a corresponding increase in R H.

  19. Acquisition of complement inhibitor serine protease factor I and its cofactors C4b-binding protein and factor H by Prevotella intermedia.

    Directory of Open Access Journals (Sweden)

    Sven Malm

    Full Text Available Infection with the Gram-negative pathogen Prevotella intermedia gives rise to periodontitis and a growing number of studies implies an association of P. intermedia with rheumatoid arthritis. The serine protease Factor I (FI is the central inhibitor of complement degrading complement components C3b and C4b in the presence of cofactors such as C4b-binding protein (C4BP and Factor H (FH. Yet, the significance of complement inhibitor acquisition in P. intermedia infection and FI binding by Gram-negative pathogens has not been addressed. Here we show that P. intermedia isolates bound purified FI as well as FI directly from heat-inactivated human serum. FI bound to bacteria retained its serine protease activity as shown in degradation experiments with (125I-labeled C4b. Since FI requires cofactors for its activity we also investigated the binding of purified cofactors C4BP and FH and found acquisition of both proteins, which retained their activity in FI mediated degradation of C3b and C4b. We propose that FI binding by P. intermedia represents a new mechanism contributing to complement evasion by a Gram-negative bacterial pathogen associated with chronic diseases.

  20. The link of C4B null allele to autism and to a family history of autoimmunity in Egyptian autistic children.

    Science.gov (United States)

    Mostafa, Gehan A; Shehab, Abeer A

    2010-06-01

    The reason behind the initiation of autoimmunity, which may have a role in autism, is not well understood. There is an association between some autoimmune disorders and complement (C) 4B null allele. We aimed to study the association between C4B null allele and autism. In addition, we are the first to investigate the association between this allele and a family history of autoimmune diseases in autistic children. Therefore, we examined the frequency of C4B null allele, by quantitative real-time PCR, in 80 autistic patients and 80 healthy matched-children. The frequency of C4B null allele was significantly higher in autistic patients (37.5%) than healthy controls (8.75%), Pfamilies of autistic children (40%) was significantly higher than healthy children (10%), Pfamily history of autoimmunity had a significant risk for association with autism (odds ratio=6, 95%, CI=2.5-14.1). C4B null allele had a significant risk for association with autism (odds ratio=6.26, 95% CI=2.55-15.36) and with a family history of autoimmunity (odds ratio=21, 95% CI=6.5-67.8). the link of C4B null allele to autism and to a family history of autoimmunity may indicate its possible contributing role to autoimmunity in autism. Copyright 2010 Elsevier B.V. All rights reserved.

  1. Why Does C5 Palsy Occur After Prophylactic Bilateral C4-5 Foraminotomy in Open-Door Cervical Laminoplasty? A Risk Factor Analysis.

    Science.gov (United States)

    Liu, Gabriel; Reyes, Ma Ramona; Riew, K Daniel

    2017-10-01

    Retrospective study. To evaluate the efficacy of bilateral C4-5 foraminotomy in preventing occurrence of postoperative C5 palsy and to identify possible risk factors for its development. A total of 70 consecutive patients who underwent open-door laminoplasty with bilateral C4-5 foraminotomy were included. Clinical, radiographic, and operative data was reviewed. Development of postoperative C5 palsy was analyzed. A total of 54 males and 16 females were reviewed. Mean age was 56 years (range, 30-86 years). The primary pathology was spondylosis in 76% of cases and ossified posterior longitudinal ligament in 21%. Radiographic evidence of C4-5 foraminal stenosis was seen in 81% of the patients. The mean duration of preoperative symptoms was 7 ± 19 months. Four (5.7%) out of 70 patients developed C5 palsy after open-door laminoplasty with bilateral C4-5 foraminotomy. Multivariate analysis showed that a long duration of preoperative symptoms (>12 months) and the presence of preoperative C4-5 T2-MRI cord signal change were statistically significant risk factors for the development of C5 palsy even after bilateral C4-5 foraminotomy in open-door laminoplasty (P C5 palsy. Prolonged duration of symptoms and presence of preoperative T2-MRI cord signal change increase the risk for developing postoperative C5 palsy despite foraminotomy.

  2. Drought stress obliterates the preference for ammonium as an N source in the C4 plant Spartina alterniflora.

    Science.gov (United States)

    Hessini, Kamel; Kronzucker, Herbert J; Abdelly, Chedly; Cruz, Cristina

    2017-06-01

    The C4 grass Spartina alterniflora is known for its unique salt tolerance and strong preference for ammonium (NH4+) as a nitrogen (N) source. We here examined whether Spartina's unique preference for NH4+ results in improved performance under drought stress. Manipulative greenhouse experiments were carried out to measure the effects of variable water availability and inorganic N sources on plant performance (growth, photosynthesis, antioxidant, and N metabolism). Drought strongly reduced leaf number and area, plant fresh and dry weight, and photosynthetic activity on all N sources, but the reduction was most pronounced on NH4+. Indeed, the growth advantage seen on NH4+ in the absence of drought, producing nearly double the biomass compared to growth on NO3-, was entirely obliterated under both intermediate and severe drought conditions (50 and 25% field capacity, respectively). Both fresh and dry weight became indistinguishable among N sources under drought. Major markers of the antioxidant capacity of the plant, the activities of the enzymes superoxide dismutase, catalase, ascorbate peroxidase, and glutathione reductase, showed higher constitutive levels on NH4+. Catalase and glutathione reductase were specifically upregulated in NH4+-fed plants with increasing drought stress. This upregulation, however, failed to protect the plants from drought stress. Nitrogen metabolism was characterized by lower constitutive levels of glutamine synthetase in NH4+-fed plants, and a rise in glutamate dehydrogenase (GDH) activity under drought, accompanied by elevated proline levels in leaves. Our results support postulates on the important role of GDH induction, and its involvement in the synthesis of compatible solutes, under abiotic stress. We show that, despite this metabolic shift, S. alterniflora's sensitivity to drought does not benefit from growth on NH4+ and that the imposition of drought stress equalizes all N-source-related growth differences observed under non

  3. Temperature-dependent absorption cross-section measurements of 1-butene (1-C4H8) in VUV and IR

    KAUST Repository

    Es-sebbar, Et-touhami

    2013-01-01

    Vacuum ultraviolet (VUV) and infrared (IR) absorption cross-section measurements of 1-butene (1-C4H8; CH2=CHCH2CH3; Butylene) are reported over the temperature range of 296-529K. The VUV measurements are performed between 115 and 205nm using synchrotron radiation as a tunable VUV light source. Fourier Transform Infrared (FTIR) spectroscopy is employed to measure absorption cross-section and band strengths in the IR region between 1.54 and 25μm (~6500-400cm-1). The measured room-temperature VUV and IR absorption cross-sections are compared with available literature data and are found to be in good agreement. The oscillator strength for the electronic transition (A1A\\'→X1A\\') around 150-205nm is determined to be 0.32±0.01.The gas temperature has a strong effect on both VUV and IR spectra. Measurements made in the VUV region show that the peak value of the band cross-section decreases and the background continuum increases with increasing gas temperature. This behavior is due to a change in the rotational and vibrational population distribution of 1-butene molecule. Similar changes in rotational population are observed in the IR spectra. Moreover, variation of the IR spectra with temperature is used to measure the enthalpy difference between syn and skew conformations of 1-butene and is found to be 0.24±0.03. kcal/mol, which is in excellent agreement with values reported in the literature. The measurements reported in this work will provide the much-needed spectroscopic information for the development of high-temperature quantitative diagnostics in combustion applications and validation of atmospheric chemistry models of extra-solar planets. © 2012 Elsevier Ltd.

  4. Leukotriene C4 increases the susceptibility of adult mice to Shiga toxin-producing Escherichia coli infection.

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    Cabrera, Gabriel; Fernández-Brando, Romina J; Mejías, María Pilar; Ramos, María Victoria; Abrey-Recalde, María Jimena; Vanzulli, Silvia; Vermeulen, Mónica; Palermo, Marina S

    2015-12-01

    Shiga toxin-producing Escherichia coli (STEC) is a food-borne pathogen that causes hemorrhagic colitis. Under some circumstances, Shiga toxin (Stx) produced within the intestinal tract enters the bloodstream, leading to systemic complications that may cause the potentially fatal hemolytic-uremic syndrome (HUS). Despite STEC human infection is characterized by acute inflammation of the colonic mucosa, little is known regarding the role of proinflammatory mediators like cysteine leukotrienes (cysLTs) in this pathology. Thus, the aim of this work was to analyze whether leukotriene C4 (LTC4) influences STEC pathogenesis in mice. We report that exogenous LTC4 pretreatment severely affected the outcome of STEC gastrointestinal infection. LTC4-pretreated (LTC4+) and STEC-infected (STEC+) mice showed an increased intestinal damage by histological studies, and a decreased survival compared to LTC4-non-pretreated (LTC4-) and STEC+ mice. LTC4+/STEC+ mice that died after the infection displayed neutrophilia and high urea levels, indicating that the cause of death was related to Stx2-toxicity. Despite the differences observed in the survival between LTC4+ and LTC4- mice after STEC infection, both groups showed the same survival after Stx2-intravenous inoculation. In addition, LTC4 pretreatment increased the permeability of mucosal intestinal barrier, as assessed by FITC-dextran absorption experiments. Altogether these results suggest that LTC4 detrimental effect on STEC infection is related to the increased passage of pathogenic factors to the bloodstream. Finally, we showed that STEC infection per se increases the endogenous LTC4 levels in the gut, suggesting that this inflammatory mediator plays a role in the pathogenicity of STEC infection in mice, mainly by disrupting the mucosal epithelial barrier. Copyright © 2015 Elsevier GmbH. All rights reserved.

  5. Circumferential vertebrectomy with reconstruction for holocervical aneurysmal bone cyst at C4 in a 15-year-old girl.

    Science.gov (United States)

    Refai, Daniel; Holekamp, Terrence; Stewart, Todd J; Leonard, Jeffrey

    2007-11-15

    The authors describe the unique case of a 15-year-old girl with a holovertebral aneurysmal bone cyst at C4, causing anterolisthesis and kyphosis, who underwent circumferential vertebrectomy with reconstruction and rigid fusion. To report an unusual manifestation of aneurysmal bone cyst, requiring special considerations for surgery. The discussion highlights emerging principles for treatment of this lesion, and cervical spine fusion, in the pediatric population. There is no previous report of a holovertebral aneurysmal bone cyst of the pediatric cervical spine. The potential for neurologic or vascular compromise from this lesion is substantial if left untreated, and the risk of recurrence or other morbidity is significantly higher unless completely resected. A 15-year-old white female presented with a 4-month history of neck pain after a mild injury, but was neurologically intact. Diagnostic imaging revealed a holovertebral, multicystic, and osteolytic lesion with multiple fluid-fluid levels in the fourth cervical vertebra. Total vertebrectomy and repair were performed with fibular strut grafts and placement of rigid anterior and posterior instrumentation. This was accomplished in a single anteroposterior operative pass. Surgical treatment produced a stable bony fusion with no neurologic or vascular sequelae. This approach minimizes the risk of recurrence and the possibility of postoperative spinal instability. Spinal aneurysmal bone cyst in children presents diverse challenges. These lesions should be treated with complete resection to minimize the chance of recurrence. In pediatric cases, defects created by resection should be corrected by fusion to minimize the risk of postoperative instability and growth abnormality. One-year followup demonstrated a stable construct, and the patient remains neurologically at her baseline.

  6. Laboratory study on the hygroscopic behavior of external and internal C2-C4 dicarboxylic acid-NaCl mixtures.

    Science.gov (United States)

    Ma, Qingxin; Ma, Jinzhu; Liu, Chang; Lai, Chengyue; He, Hong

    2013-09-17

    Atmospheric aerosol is usually found to be a mixture of various inorganic and organic components in field measurements, whereas the effect of this mixing state on the hygroscopicity of aerosol particles has remained unknown. In this study, the hygroscopic behavior of mixtures of C2-C4 dicarboxylic acids and NaCl was investigated. For both externally and internally mixed malonic acid-NaCl and succinic acid-NaCl particles, correlation between water content and chemical composition was observed and the water content of these mixtures at relative humidity (RH) above 80% can be well predicted by the Zdanovskii-Stokes-Robinson (ZSR) method. In contrast, a nonlinear relation between the total water content of the mixtures and the water content of each chemical composition separately was found for oxalic acid-NaCl mixtures. Compared to the values predicted by the ZSR method, the dissolution of oxalic acid in external mixtures resulted in an increase in the total water content, whereas the formation of less hygroscopic disodium oxalate in internal mixtures led to a significant decrease in the total water content. Furthermore, we found that the hygroscopicity of the sodium dicarboxylate plays a critical role in determining the aqueous chemistry of dicarboxylic acid-NaCl mixtures during the humidifying and dehumidifying process. It was also found that the hydration of oxalic acid and the deliquescence of NaCl did not change in external oxalic acid-NaCl mixtures. The deliquescence relative humidity (DRHs) for both malonic acid and NaCl decreased in both external and internal mixtures. These results could help in understanding the conversion processes of dicarboxylic acids to dicarboxylate salts, as well as the substitution of Cl by oxalate in the atmosphere. It was demonstrated that the effect of coexisting components on the hygroscopic behavior of mixed aerosols should not be neglected.

  7. Isomérisation des paraffines de C4 à C7 sur catalyseurs zéolithiques. Revue bibliographique Isomerization of C4 to C7 Paraffins on Zeolitic Catalysts (Bibliographic Review

    Directory of Open Access Journals (Sweden)

    Belloum M.

    2006-11-01

    Full Text Available L'isomérisation des alcanes connaît un nouvel intérêt, depuis que la législation a prévu, par souci de protection de l'environnement, la suppression des alkyls de plomb dans les essences à l'horizon 1992. Cette réaction catalytique permet, en partant de n-paraffines de faible indice d'octane, issues du réformage catalytique ou de la distillation directe, d'obtenir des iso-paraffines présentant un indice d'octane beaucoup plus élevé. Elle est thermodynamiquement favorisée à basse température et nécessite par conséquent l'utilisation de catalyseurs développant une acidité importante. Deux types de catalyseurs sont actuellement utilisés industriellement : les catalyseurs à base de Pt sur lumine chlorée et les catalyseurs zéolithiques à base de Pt sur mordinite. Ces derniers sont considérés comme étant la nouvelle génération de catalyseurs. Ils présentent l'avantage d'être faciles à mettre en oeuvre et d'être beaucoup moins sensibles à la présence de poisons tels que soufre et eau dans la charge. Cependant ils conduisent à un gain d'octane considérablement plus faible que celui obtenu avec les catalyseurs Pt sur alumine chlorée. Cette étude bibliographique fait le point sur les différents mécanismes invoqués suivant le type de catalyseurs, les données cinétiques obtenues dans la littérature, et les différents procédés mis en oeuvre. Elle permet en particulier de mettre en évidence les contributions respectives des fonctions acides et métalliques pour l'isomérisation des alcanes de C4 à C7. En effet, il apparaît que suivant le type de catalyseurs utilisés, le mécanisme de la traction peut être bifonctionnel ou monofonctionnel acide. Dans certains cas, il pourrait même y avoir superposition des 2 mécanismes. L'étude de la longueur de la chaîne carbonée sur la réaction d'isomérisation ainsi que l'influence de la présence de composés cycliques, aromatiques ou non, ont également

  8. RP-UHPLC-UV-ESI-MS/MS analysis of LPMO generated C4-oxidized gluco-oligosaccharides after non-reductive labeling with 2-aminobenzamide.

    Science.gov (United States)

    Frommhagen, Matthias; van Erven, Gijs; Sanders, Mark; van Berkel, Willem J H; Kabel, Mirjam A; Gruppen, Harry

    2017-08-07

    Lytic polysaccharide monooxygenases (LPMOs) are able to cleave recalcitrant polysaccharides, such as cellulose, by oxidizing the C1 and/or C4 atoms. The analysis of the resulting products requires a variety of analytical techniques. Up to now, these techniques mainly focused on the identification of non-oxidized and C1-oxidized oligosaccharides. The analysis of C4-oxidized gluco-oligosaccharides is mostly performed by using high pressure anion exchange chromatography (HPAEC). However, the alkaline conditions used during HPAEC analysis lead to tautomerization of C4-oxidized gluco-oligosaccharides, which limits the use of this technique. Here, we describe the use of reverse phase-ultra high performance liquid chromatography (RP-UHPLC) in combination with non-reductive 2-aminobenzamide (2-AB) labeling. Non-reductive 2-AB labeling enabled separation of C4-oxidized gluco-oligosaccharides from their non-oxidized counterparts. Moreover, RP-UHPLC does not require buffered mobile phases, which reduce mass spectrometry (MS) sensitivity. The latter is seen as an advantage over other techniques such as hydrophilic interaction liquid chromatography and porous graphitized carbon coupled to MS. RP-UHPLC coupled to UV detection and mass spectrometry allowed the identification of both labeled non-oxidized and C4-oxidized oligosaccharides. Non-reductive labeling kept the ketone at the C4-position of LPMO oxidized oligosaccharides intact, while selective reducing agents such as sodium triacetoxyborohydride (STAB) reduced this ketone group. Our results show that RP-UHPLC-UV-ESI-MS in combination with non-reductively 2-AB labeling is a suitable technique for the separation and identificat