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Sample records for higher plant counterparts

  1. Physcomitrella HMGA-type proteins display structural differences compared to their higher plant counterparts

    SciTech Connect

    Lyngaard, Carina; Stemmer, Christian; Stensballe, Allan; Graf, Manuela; Gorr, Gilbert; Decker, Eva; Grasser, Klaus D.

    2008-10-03

    High mobility group (HMG) proteins of the HMGA family are chromatin-associated proteins that act as architectural factors in nucleoprotein structures involved in gene transcription. To date, HMGA-type proteins have been studied in various higher plant species, but not in lower plants. We have identified two HMGA-type proteins, HMGA1 and HMGA2, encoded in the genome of the moss model Physcomitrella patens. Compared to higher plant HMGA proteins, the two Physcomitrella proteins display some structural differences. Thus, the moss HMGA proteins have six (rather than four) AT-hook DNA-binding motifs and their N-terminal domain lacks similarity to linker histone H1. HMGA2 is expressed in moss protonema and it localises to the cell nucleus. Typical of HMGA proteins, HMGA2 interacts preferentially with A/T-rich DNA, when compared with G/C-rich DNA. In cotransformation assays in Physcomitrella protoplasts, HMGA2 stimulated reporter gene expression. In summary, our data show that functional HMGA-type proteins occur in Physcomitrella.

  2. Polyesters in higher plants.

    PubMed

    Kolattukudy, P E

    2001-01-01

    Polyesters occur in higher plants as the structural component of the cuticle that covers the aerial parts of plants. This insoluble polymer, called cutin, attached to the epidermal cell walls is composed of interesterified hydroxy and hydroxy epoxy fatty acids. The most common chief monomers are 10,16-dihydroxy C16 acid, 18-hydroxy-9,10 epoxy C18 acid, and 9,10,18-trihydroxy C18 acid. These monomers are produced in the epidermal cells by omega hydroxylation, in-chain hydroxylation, epoxidation catalyzed by P450-type mixed function oxidase, and epoxide hydration. The monomer acyl groups are transferred to hydroxyl groups in the growing polymer at the extracellular location. The other type of polyester found in the plants is suberin, a polymeric material deposited in the cell walls of a layer or two of cells when a plant needs to erect a barrier as a result of physical or biological stress from the environment, or during development. Suberin is composed of aromatic domains derived from cinnamic acid, and aliphatic polyester domains derived from C16 and C18 cellular fatty acids and their elongation products. The polyesters can be hydrolyzed by pancreatic lipase and cutinase, a polyesterase produced by bacteria and fungi. Catalysis by cutinase involves the active serine catalytic triad. The major function of the polyester in plants is as a protective barrier against physical, chemical, and biological factors in the environment, including pathogens. Transcriptional regulation of cutinase gene in fungal pathogens is being elucidated at a molecular level. The polyesters present in agricultural waste may be used to produce high value polymers, and genetic engineering might be used to produce large quantities of such polymers in plants. PMID:11217409

  3. Pleurotus ostreatus biofilms exhibit higher tolerance to toxicants than free-floating counterparts.

    PubMed

    Pesciaroli, Lorena; Petruccioli, Maurizio; Federici, Federico; D'Annibale, Alessandro

    2013-01-01

    The MBEC(TM)-High Throughput Assay based on the Calgary Biofilm Device was used to produce and to characterize Pleurotus ostreatus biofilms. Hydroxyapatite coating of pegs was required to enable biofilm attachment; biofilm amounts and homogeneity of distribution were markedly improved upon removal of non-sessile biomass after 48 h from inoculation. Scanning electron microscopy showed surface-associated and multi-layered growth stabilized by the presence of an extracellular matrix (ECM). Biofilms had higher contents of total sugars and ECM than their free-floating counterparts. Tolerance to Cr(VI) in the former was about twice that of the latter as inferred by the respective inhibitory concentrations (48.4 vs 24.1 mM and 114.5 vs 61.0 mM in 4- and 7-d-old cultures, respectively). Biofilms also displayed superior olive-mill wastewater (OMW) treatment efficiency along 5 consecutive batches leading to chemical oxygen demand and total phenol removals higher than 50 and 90%, respectively. Laccase activity peaks in biofilm cultures grown on OMW were significantly higher than those in free-floating cultures. PMID:23998200

  4. Plant mitochondrial rhomboid, AtRBL12, has different substrate specificity from its yeast counterpart.

    PubMed

    Kmiec-Wisniewska, Beata; Krumpe, Katrin; Urantowka, Adam; Sakamoto, Wataru; Pratje, Elke; Janska, Hanna

    2008-09-01

    Rhomboid proteins comprise a class of serine proteases that are conserved in all kingdoms of organisms. They contain six or seven transmembrane helices and control a wide range of cellular functions and developmental processes by intramembrane proteolysis. This paper provides experimental evidence for the existence of rhomboid proteases in plant mitochondria and chloroplasts. Among 15 putative rhomboid-like proteins in Arabidopsis thaliana, we selected five predicted as mitochondrially targeted. For these proteins we performed the GFP transient assay, and identified two homologues, AtRBL11 (At5g25752) and AtRBL12 (At1g18600) to be targeted into plastids and mitochondria, respectively. Phylogenetic analysis reveals that AtRBL12 or AtRBL11 have only one clear orthologue in plant species with completely sequenced genomes. Complementation of the yeast lacking a functional copy of mitochondrial rhomboid with AtRBL12 indicates that this plant protease, in contrast to the human orthologue, does not recognize the yeast substrates, cytochrome c peroxidase (Ccp1) or dynamin-like GTPase (Mgm1). In agreement with this, we did not observe processing of Mgm1 when labeled precursor of this protein was incubated in vitro with Arabidopsis mitochondrial extract. Our results imply that plant mitochondrial rhomboids function in a specific manner and thus differ from their yeast and mammal counterparts. PMID:18543065

  5. Correction: Unexpected higher stabilisation of two classical antiaromatic frameworks with a ruthenium fragment compared to the osmium counterpart: origin probed by DFT calculations.

    PubMed

    Wu, Jingjing; Hao, Yulei; An, Ke; Zhu, Jun

    2016-01-25

    Correction for 'Unexpected higher stabilisation of two classical antiaromatic frameworks with a ruthenium fragment compared to the osmium counterpart: origin probed by DFT calculations' by Jingjing Wu et al., Chem. Commun., 2016, 52, 272-275. PMID:26699929

  6. Chromosomal replicons of higher plants

    SciTech Connect

    Van't Hof, J.

    1987-03-16

    This brief discussion of replicons of higher plants offers a glimpse into the properties of chromosomal DNA replication. It gives evidence that the S phase of unrelated plant species is comprised of temporally ordered replicon families that increase in number with genome size. This orderly process, which assures a normal inheritance of genetic material to recipient daughter cells, is maintained at the level of replicon clusters by two mutually exclusive mechanisms, one involving the rate at which single replicons replicate their allotment of DNA, and another by means of the tempo-pause. The same two mechanisms are used by cells to alter the pattern of chromosomal DNA replication just prior to and during normal development. Both mechanisms are genetically determined and produce genetic effects when disturbed of disrupted by additional non-conforming DNAs. Further insight into how these two mechanisms operate requires more molecular information about the nature of replicons and the factors that govern when a replicon family replicates. Plant material is a rich and ideal source for this information just awaiting exploitation. 63 refs.

  7. Fuel oils from higher plants

    SciTech Connect

    Calvin, M.

    1985-03-01

    A summary of the types of plants available for converting solar energy to fuel and materials on an annually renewable basis is presented. Sugar cane, seed oils, herbaceous plants (Hevea, Euphorbia, Asclepias), hydrocarbon producing trees (Eucalystus globulus, Pittosporum, Copaifera), and algae are discussed. Emphasis is placed on the development of ''energy agriculture'' and the use of plants to synthesize hydrocarbon-like materials especially in the less developed areas of the world. (DMC)

  8. Unexpected higher stabilisation of two classical antiaromatic frameworks with a ruthenium fragment compared to the osmium counterpart: origin probed by DFT calculations.

    PubMed

    Wu, Jingjing; Hao, Yulei; An, Ke; Zhu, Jun

    2016-01-01

    Density functional theory (DFT) calculations were carried out to investigate the stability and aromaticity of metallapentalocyclobutadienes. The results reveal unexpected higher stabilisation achieved with a 4d ruthenium fragment compared to the 5d [corrected] osmium counterpart. Moreover, direct 1-3 metal-carbon bonding in the metallabutadiene unit of these two complexes is negligible. PMID:26505956

  9. Gravitropism in Higher Plant Shoots

    PubMed Central

    Wheeler, Raymond M.; Salisbury, Frank B.

    1981-01-01

    It has long been known that applied ethylene can redirect the gravitropic response, but only occasionally has it been suggested that ethylene normally plays a role in gravitropism. Two inhibitors of ethylene synthesis [Co2+ and aminoethoxyvinylglycine (AVG)] and two inhibitors of ethylene action (Ag+ and CO2) were shown to delay the gravitropic response of cocklebur (Xanthium strumarium L.), tomato (Lycopersicon esculentum Mill.), and castor bean (Ricinus communis L.) stems. Gentle shaking on a mechanical shaker does not inhibit the gravitropic response, but vigorous hand shaking for 120 seconds delays the response somewhat. AVG and Ag+ further delay the response of mechanically stimulated plants. AVG delays the response of defoliated and of decapitated plants. Plants laid on their side and restricted so that they cannot bend upward store both bending energy and gravitropic stimulus; they bend immediately when released from restriction (stored energy) and continue to bend for some hours after (stored stimulus). AVG retards the storage of bending energy but not of stimulus. In gravitropism, graviperception may first stimulate ethylene evolution, which may then influence bending directly, or responses involving ethylene could be more indirect. PMID:16661736

  10. Undifferentiated bronchial fibroblasts derived from asthmatic patients display higher elastic modulus than their non-asthmatic counterparts.

    PubMed

    Sarna, Michal; Wojcik, Katarzyna A; Hermanowicz, Pawel; Wnuk, Dawid; Burda, Kvetoslava; Sanak, Marek; Czyż, Jarosław; Michalik, Marta

    2015-01-01

    During asthma development, differentiation of epithelial cells and fibroblasts towards the contractile phenotype is associated with bronchial wall remodeling and airway constriction. Pathological fibroblast-to-myofibroblast transition (FMT) can be triggered by local inflammation of bronchial walls. Recently, we have demonstrated that human bronchial fibroblasts (HBFs) derived from asthmatic patients display some inherent features which facilitate their FMT in vitro. In spite of intensive research efforts, these properties remain unknown. Importantly, the role of undifferentiated HBFs in the asthmatic process was systematically omitted. Specifically, biomechanical properties of undifferentiated HBFs have not been considered in either FMT or airway remodeling in vivo. Here, we combine atomic force spectroscopy with fluorescence microscopy to compare mechanical properties and actin cytoskeleton architecture of HBFs derived from asthmatic patients and non-asthmatic donors. Our results demonstrate that asthmatic HBFs form thick and aligned 'ventral' stress fibers accompanied by enlarged focal adhesions. The differences in cytoskeleton architecture between asthmatic and non-asthmatic cells correlate with higher elastic modulus of asthmatic HBFs and their increased predilection to TGF-β-induced FMT. Due to the obvious links between cytoskeleton architecture and mechanical equilibrium, our observations indicate that HBFs derived from asthmatic bronchi can develop considerably higher static tension than non-asthmatic HBFs. This previously unexplored property of asthmatic HBFs may be potentially important for their myofibroblastic differentiation and bronchial wall remodeling during asthma development. PMID:25679502

  11. Regulation of cell division in higher plants

    SciTech Connect

    Jacobs, T.W.

    1992-01-01

    Cell division is arguably the most fundamental of all developmental processes. In higher plants, mitotic activity is largely confined to foci of patterned cell divisions called meristems. From these perpetually embryonic tissues arise the plant's essential organs of light capture, support, protection and reproduction. Once an adequate understanding of plant cell mitotic regulation is attained, unprecedented opportunities will ensue for analyzing and genetically controlling diverse aspects of development, including plant architecture, leaf shape, plant height, and root depth. The mitotic cycle in a variety of model eukaryotic systems in under the control of a regulatory network of striking evolutionary conservation. Homologues of the yeast cdc2 gene, its catalytic product, p34, and the cyclin regulatory subunits of the MPF complex have emerged as ubiquitous mitotic regulators. We have cloned cdc2-like and cyclin genes from pea. As in other eukaryotic model systems, p34 of Pisum sativum is a subunit of a high molecular weight complex which binds the fission yeast p13 protein and displays histone H1 kinase activity in vitro. Our primary objective in this study is to gain baseline information about the regulation of this higher plant cell division control complex in non-dividing, differentiated cells as well as in synchronous and asynchronous mitotic cells. We are investigating cdc2 and cyclin expression at the levels of protein abundance, protein phosphorylation and quaternary associations.

  12. Nickel: a micronutrient essential for higher plants

    SciTech Connect

    Brown, P.H.; Welch, R.M.; Cary, E.E.

    1987-11-01

    Nickel was established as an essential micronutrient for the growth of temperate cereal crops. Grain from barley (Hordeum vulgare L. cv Onda; containing 40 to 80 nanograms of Ni per gram dry weight) grown in solution culture with negligible Ni concentrations (<30 nanograms of Ni per liter) exhibited greatly reduced germination rates (i.e. 50% less than grain from Ni-adequate plants) and seeding vigor of the viable grain was greatly depressed. Grain containing less than 30 nanograms per gram dry weight was inviable. Under Ni-deficient conditions, barley plants fail to produce viable grain because of a disruption of the maternal plants normal grain-filling and maturation processes that occur following formation of the grain embryo. The observations that (a) barley plants fail to complete their life cycle in the absence of Ni and (b) addition of Ni to the growth medium completely alleviates deficiency symptoms in the maternal plants satisfies the essentiality criteria; thus Ni should be considered a micronutrient for cereals. Because Ni is required by legumes, and is now established for cereals, the authors conclude that Ni should be added to the list of micronutrients essential for all higher plant growth.

  13. Fate of excess sulfur in higher plants

    SciTech Connect

    Rennenberg, H.

    1984-01-01

    The mechanisms which have evolved in higher plants to cope with excess sulfur in their environments are reviewed. Survival in a sulfur-rich environment is seldom achieved through avoidance of the intake of sulfur. The presence of excess sulfur in the soil or in the air usually results in an intake of excess sulfur into plants. An immediate injury by the excess sulfur taken up is, however, prevented by a series of metabolic processes. Storage of excess sulfur in a metabolically inactive compartment, i.e. the vacuole, appears to occur in most plants. The finding of a storage of glutathione is several investigations suggests that with increasing accumulation of sulfate its reduction also increases. Under these conditions the cysteine concentration in different compartments of the cell may still be maintained at a low level by the incorporation of the excess cysteine synthesized into glutathione. This peptide appears to be the storage form of reduced sulfur in higher plants. 167 references, 2 figures.

  14. Specificity of Cycloheximide in Higher Plant Systems

    PubMed Central

    Ellis, R. J.; MacDonald, I. R.

    1970-01-01

    Although cycloheximide is extremely inhibitory to protein synthesis in vivo in higher plants, the reported insensitivity of some plant ribosomes suggests that it may not invariably act at the ribosomal level. This suggestion is reinforced by results obtained with red beet storage tissue disks, the respiration of which is stimulated by cycloheximide at 1 microgram per milliliter. Inorganic ion uptake by these disks is inhibited by cycloheximide at 1 microgram per milliliter while the uptake of organic compounds, by comparison, is unaffected. Ion uptake by all nongreen tissues tested is inhibited by cycloheximide, but leaf tissue is unaffected, indicating that the ion absorption mechanism in the leaf may differ fundamentally from that in the root. It is concluded that cycloheximide can affect cellular metabolism other than by inhibiting protein synthesis and that the inhibition of ion uptake may be due to disruption of the energy supply. PMID:16657440

  15. Effect of free fall on higher plants.

    NASA Technical Reports Server (NTRS)

    Gordon, S. A.

    1973-01-01

    The influence of exposure to the free-fall state on the orientation, morphogenesis, physiology, and radiation response of higher plants is briefly summarized. It is proposed that the duration of the space-flight experiments has been to brief to permit meaningful effects of free fall on general biochemistry, growth, and development to appear. However, two types of significant effect did occur. The first is on differential growth - i.e., tropism and epinasty - resulting from the absence of a normal geostimulus. For these phenomena it is suggested that ground-based experiments with the clinostat would suffice to mimic the effect of the free-fall state. The second is an apparent interaction between the radiation response and some flight condition, yielding an enhanced microspore abortion, a disturbed spindle function, and a stunting of stamen hairs. It is suggested that this apparent interaction may be derived from a shift in the rhythm of the cell cycle, induced by the free fall.

  16. Endogenous peptide elicitors in higher plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plant defense responses against invading organisms are initiated through the perception of molecules associated with attacking microbes and herbivores by pattern recognition receptors. In addition to elicitor molecules derived from attacking organisms, plants recognize host-derived molecules. Thes...

  17. Developing Higher Plant Systems in Space

    NASA Technical Reports Server (NTRS)

    Krikorian, A. D.

    1983-01-01

    The effects of hypogravity and microgravity environments on plant cells are discussed. Experiments on embryos of carrots are discussed. Simulation and spacecraft environments were used in experiments.

  18. Conserved noncoding sequences (CNSs) in higher plants.

    PubMed

    Freeling, Michael; Subramaniam, Shabarinath

    2009-04-01

    Plant conserved noncoding sequences (CNSs)--a specific category of phylogenetic footprint--have been shown experimentally to function. No plant CNS is conserved to the extent that ultraconserved noncoding sequences are conserved in vertebrates. Plant CNSs are enriched in known transcription factor or other cis-acting binding sites, and are usually clustered around genes. Genes that encode transcription factors and/or those that respond to stimuli are particularly CNS-rich. Only rarely could this function involve small RNA binding. Some transcribed CNSs encode short translation products as a form of negative control. Approximately 4% of Arabidopsis gene content is estimated to be both CNS-rich and occupies a relatively long stretch of chromosome: Bigfoot genes (long phylogenetic footprints). We discuss a 'DNA-templated protein assembly' idea that might help explain Bigfoot gene CNSs. PMID:19249238

  19. The cytoskeleton and gravitropism in higher plants

    NASA Technical Reports Server (NTRS)

    Blancaflor, Elison B.

    2002-01-01

    The cellular and molecular mechanisms underlying the gravitropic response of plants have continued to elude plant biologists despite more than a century of research. Lately there has been increased attention on the role of the cytoskeleton in plant gravitropism, but several controversies and major gaps in our understanding of cytoskeletal involvement in gravitropism remain. A major question in the study of plant gravitropism is how the cytoskeleton mediates early sensing and signal transduction events in plants. Much has been made of the actin cytoskeleton as the cellular structure that sedimenting amyloplasts impinge upon to trigger the downstream signaling events leading to the bending response. There is also strong molecular and biochemical evidence that the transport of auxin, an important player in gravitropism, is regulated by actin. Organizational changes in microtubules during the growth response phase of gravitropism have also been well documented, but the significance of such reorientations in controlling differential cellular growth is unclear. Studies employing pharmacological approaches to dissect cytoskeletal involvement in gravitropism have led to conflicting results and therefore need to be interpreted with caution. Despite the current controversies, the revolutionary advances in molecular, biochemical, and cell biological techniques have opened up several possibilities for further research into this difficult area. The myriad proteins associated with the plant cytoskeleton that are being rapidly characterized provide a rich assortment of candidate regulators that could be targets of the gravity signal transduction chain. Cytoskeletal and ion imaging in real time combined with mutant analysis promises to provide a fresh start into this controversial area of research.

  20. Effects of simulated hypogravity on respiration and photosynthesis of higher plants.

    PubMed

    Ward, C H; King, J M

    1979-01-01

    Clinostat rotation about a horizontal axis mechanically cancels the directional component of the gravity force vector which is biologically sensed by plants. However, efficiency of clinostats as simulators of weightlessness for prolonged periods has not been demonstrated conclusively. Morphological appearance of plants in orbital flight may resemble their counterparts on earth-based clinostats, but physiological responses may differ. Photosynthesis experiments with algae have been performed in satellites orbiting the earth, but similar experiments with higher plants have not been conducted. This paper describes an experimental apparatus for measurement of photosynthetic and respiratory rates of whole plants on rotating clinostats. Initial experiments show an enhancement of gas exchange during rotation about a horizontal axis. PMID:12008718

  1. Higher plant mitochondrial DNA: Genomes, genes, mutants, transcription, translation

    SciTech Connect

    Not Available

    1986-01-01

    This volume contains brief summaries of 63 presentations given at the International Workshop on Higher Plant Mitochondrial DNA. The presentations are organized into topical discussions addressing plant genomes, mitochondrial genes, cytoplasmic male sterility, transcription, translation, plasmids and tissue culture. (DT)

  2. Passive CO2 concentration in higher plants.

    PubMed

    Sage, Rowan F; Khoshravesh, Roxana

    2016-06-01

    Photorespiratory limitations on C3 photosynthesis are substantial in warm, low CO2 conditions. To compensate, certain plants evolved mechanisms to actively concentrate CO2 around Rubisco using ATP-supported CO2 pumps such as C4 photosynthesis. Plants can also passively accumulate CO2 without additional ATP expenditure by localizing the release of photorespired and respired CO2 around Rubisco that is diffusively isolated from peripheral air spaces. Passive accumulation of photorespired CO2 occurs when glycine decarboxylase is localized to vascular sheath cells in what is termed C2 photosynthesis, and through forming sheaths of chloroplasts around the periphery of mesophyll cells. The peripheral sheaths require photorespired CO2 to re-enter chloroplasts where it can be refixed. Passive accumulation of respiratory CO2 is common in organs such as stems, fruits and flowers, due to abundant heterotrophic tissues and high diffusive resistance along the organ periphery. Chloroplasts within these organs are able to exploit this high CO2 to reduce photorespiration. CO2 concentration can also be enhanced passively by channeling respired CO2 from roots and rhizomes into photosynthetic cells of stems and leaves via lacunae, aerenchyma and the xylem stream. Through passive CO2 concentration, C3 species likely improved their carbon economy and maintained fitness during episodes of low atmospheric CO2. PMID:27058940

  3. Lipid Peroxidation in Higher Plants 1

    PubMed Central

    Schmidt, Arno; Kunert, Karl Josef

    1986-01-01

    To study the role of glutathione reductase in lipid peroxidation, bean leaves (Phaseolus vulgaris) cv Fori were treated with the herbicide acifluorfen-sodium (sodium 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoic acid). Acifluorfen is a potent inducer of lipid peroxidation. In beans, decrease of acid-soluble SH-compounds and lipid peroxidation, measured as ethane evolution, were the toxic events after treatment of leaves with acifluorfen. As a primary response to peroxidation, increased production of antioxidants, such as vitamin C and glutathione, was found. This was followed by elevation of glutathione reductase activity. Enhanced activity of the enzyme prevented both further decline of acid-soluble SH-compounds and lipid peroxidation. Increased production of antioxidants and elevated activity of antioxidative enzymes, like glutathione reductase, seem to be a general strategy to limit toxic peroxidation in plants. PMID:16665095

  4. Gravitropism in Higher Plant Shoots 1

    PubMed Central

    Wheeler, Raymond M.; White, Rosemary G.; Salisbury, Frank B.

    1986-01-01

    Ethylene at 1.0 and 10.0 cubic centimeters per cubic meter decreased the rate of gravitropic bending in stems of cocklebur (Xanthium strumarium L.) and tomato (Lycopersicon esculentum Mill), but 0.1 cubic centimeter per cubic meter ethylene had little effect. Treating cocklebur plants with 1.0 millimolar aminoethoxyvinylglycine (AVG) (ethylene synthesis inhibitor) delayed stem bending compared with controls, but adding 0.1 cubic centimeter per cubic meter ethylene in the surrounding atmosphere (or applying 0.1% ethephon solution) partially restored the rate of bending of AVG-treated plants. Ethylene increases in bending stems, and AVG inhibits this. Virtually all newly synthesized ethylene appeared in bottom halves of horizontal stems, where ethylene concentrations were as much as 100 times those in upright stems or in top halves of horizontal stems. This was especially true when horizontal stems were physically restrained from bending. Ethylene might promote cell elongation in bottom tissues of a horizontal stem or indicate other factors there (e.g. a large amount of `functioning' auxin). Or top and bottom tissues may become differentially sensitive to ethylene. Auxin applied to one side of a vertical stem caused extreme bending away from that side; gibberellic acid, kinetin, and abscisic acid were without effect. Acidic ethephon solutions applied to one side of young seedlings of cocklebur, tomato, sunflower (Helianthus annuus L.), and soybean (Glycine max [L.] Merr.) caused bending away from that side, but neutral ethephon solutions did not cause bending. Buffered or unbuffered acid (HCl) caused similar bending. Neutral ethephon solutions produced typical ethylene symptoms (i.e. epinasty, inhibition of stem elongation). HCl or acidic ethephon applied to the top of horizontal stems caused downward bending, but these substances applied to the bottom of such stems inhibited growth and upward bending—an unexpected result. PMID:11539089

  5. Controlled Ecological Life Support System: Use of Higher Plants

    NASA Technical Reports Server (NTRS)

    Tibbits, T. W.; Alford, D. K.

    1982-01-01

    Results of two workshops concerning the use of higher plants in Controlled Ecological Life Support Systems (CELSS) are summarized. Criteria for plant selection were identified from these categories: food production, nutrition, oxygen production and carbon dioxide utilization, water recycling, waste recycling, and other morphological and physiological considerations. Types of plant species suitable for use in CELSS, growing procedures, and research priorities were recommended. Also included are productivity values for selected plant species.

  6. Effect of iodine disinfection products on higher plants

    NASA Technical Reports Server (NTRS)

    Janik, D.; Macler, B.; Macelroy, R. D.; Thorstenson, Y.; Sauer, R.

    1989-01-01

    Iodine is used to disinfect potable water on United States spacecraft. Iodinated potable water will likely be used to grow plants in space. Little is known about the effects of iodine disinfection products on plants. Seeds of select higher plants were germinated in water iodinated using the Shuttle Microbial Check Valve, and water to which measured amounts of iodine was added. Percent germination was decreased in seeds of most species germinated in iodinated water. Beans were most affected. Germination rates, determined from germination half-times, were decreased for beans germinated in iodinated water, and water to which iodide was added. Development was retarded and rootlets were conspicuously absent in bean and several other plant species germinated in iodinated water. Iodide alone did not elicit these responses. Clearly iodine disinfection products can affect higher plants. These effects must be carefully considered for plant experimentation and cultivation in space, and in design and testing of closed environmental life support systems.

  7. Controlled ecological life support system higher plant flight experiments

    NASA Technical Reports Server (NTRS)

    Tibbitts, T. W.; Wheeler, R. M.

    1984-01-01

    Requirements for spaceflight experments which involve higher plants were determined. The plants are studied for use in controlled ecological life support systems (CELSS). Two categories of research requirements are discussed: (1) the physical needs which include nutrient, water and gas exchange requirements; (2) the biological and physiological functions which affect plants in zero gravity environments. Physical problems studies are given the priority since they affect all biological experiments.

  8. Discovery of new anticancer agents from higher plants

    PubMed Central

    Pan, Li; Chai, Hee-Byung; Kinghorn, A. Douglas

    2012-01-01

    1. ABSTRACT Small organic molecules derived from higher plants have been one of the mainstays of cancer chemotherapy for approximately the past half a century. In the present review, selected single chemical entity natural products of plant origin and their semi-synthetic derivatives currently in clinical trials are featured as examples of new cancer chemotherapeutic drug candidates. Several more recently isolated compounds obtained from plants showing promising in vivo biological activity are also discussed in terms of their potential as anticancer agents, with many of these obtained from species that grow in tropical regions. Since extracts of only a relatively small proportion of the ca. 300,000 higher plants on earth have been screened biologically to date, bioactive compounds from plants should play an important role in future anticancer drug discovery efforts. PMID:22202049

  9. The continuing search for antitumor agents from higher plants

    PubMed Central

    Pan, Li; Chai, Heebyung; Kinghorn, A. Douglas

    2009-01-01

    Plant secondary metabolites and their semi-synthetic derivatives continue to play an important role in anticancer drug therapy. In this short review, selected single chemical entity antineoplastic agents from higher plants that are currently in clinical trials as cancer chemotherapy drug candidates are described. These compounds are representative of a wide structural diversity. In addition, the approaches taken toward the discovery of anticancer agents from tropical plants in the laboratory of the authors are summarized. The successful clinical utilization of cancer chemotherapeutic agents from higher plants has been evident for about half a century, and, when considered with the promising pipeline of new plant-derived compounds now in clinical trials, this augurs well for the continuation of drug discovery research efforts to elucidate additional candidate substances of this type. PMID:20228943

  10. Allelopathic bacteria and their impact on higher plants.

    PubMed

    Barazani, O; Friedman, J

    2001-01-01

    The impact of allelopathic, nonpathogenic bacteria on plant growth in natural and agricultural ecosystems is discussed. In some natural ecosystems, evidence supports the view that in the vicinity of some allelopathically active perennials (e.g., Adenostoma fasciculatum, California), in addition to allelochemicals leached from the shrub's canopy, accumulation of phytotoxic bacteria or other allelopathic microorganisms amplify retardation of annuals. In agricultural ecosystems allelopathic bacteria may evolve in areas where a single crop is grown successively, and the resulting yield decline cannot be restored by application of minerals. Transfer of soils from areas where crop suppression had been recorded into an unaffected area induced crop retardation without readily apparent symptoms of plant disease. Susceptibility of higher plants to deleterious rhizobacteria is often manifested in sandy or so-called skeletal soils. Evaluation of phytotoxic activity under controlled conditions, as well as ways to apply allelopathic bacteria in the field, is approached. The allelopathic effect may occur directly through the release of allelochemicals by a bacterium that affects susceptible plant(s) or indirectly through the suppression of an essential symbiont. The process is affected by nutritional and other environmental conditions, some may control bacterial density and the rate of production of allelochemicals. Allelopathic nonpathogenic bacteria include a wide range of genera and secrete a diverse group of plant growth-mediating allelochemicals. Although a limited number of plant growth-promoting bacterial allelochemicals have been identified, a considerable number of highly diversified growth-inhibiting allelochemicals have been isolated and characterized. Some species may produce more than one allelochemical; for example, three different phyotoxins, geldanamycin, nigericin, and hydanthocidin, were isolated from Streptomyces hygroscopicus. Efforts to introduce naturally

  11. Heat tolerance of higher plants cenosis to damaging air temperatures

    NASA Astrophysics Data System (ADS)

    Ushakova, Sofya; Shklavtsova, Ekaterina

    Designing sustained biological-technical life support systems (BTLSS) including higher plants as a part of a photosynthesizing unit, it is important to foresee the multi species cenosis reaction on either stress-factors. Air temperature changing in BTLSS (because of failure of a thermoregulation system) up to the values leading to irreversible damages of photosynthetic processes is one of those factors. However, it is possible to increase, within the certain limits, the plant cenosis tolerance to the unfavorable temperatures’ effect due to the choice of the higher plants possessing resistance both to elevated and to lowered air temperatures. Besides, the plants heat tolerance can be increased when subjecting them during their growing to the hardening off temperatures’ effect. Thus, we have come to the conclusion that it is possible to increase heat tolerance of multi species cenosis under the damaging effect of air temperature of 45 (°) СC.

  12. Fractionation of metal stable isotopes by higher plants

    USGS Publications Warehouse

    Von Blanckenburg, F.; Von Wiren, N.; Guelke, M.; Weiss, D.J.; Bullen, T.D.

    2009-01-01

    Higher plants induce chemical reactions in the rhizosphere, facilitating metal uptake by roots. Fractionation of the isotopes in nutrients such as calcium, iron, magnesium, and zinc produces a stable isotope composition in the plants that generally differs from that of the growth medium. Isotope fractionation also occurs during transport of the metals within most plants, but its extent depends on plant species and on the metal, in particular, on the metal's redox state and what ligand it is bound to. The metal stable isotope variations observed in plants create an isotope signature of life at the Earth's surface, contributing substantially to our understanding of metal cycling processes in the environment and in individual organisms.

  13. The Interactions of Aquaporins and Mineral Nutrients in Higher Plants.

    PubMed

    Wang, Min; Ding, Lei; Gao, Limin; Li, Yingrui; Shen, Qirong; Guo, Shiwei

    2016-01-01

    Aquaporins, major intrinsic proteins (MIPs) present in the plasma and intracellular membranes, facilitate the transport of small neutral molecules across cell membranes in higher plants. Recently, progress has been made in understanding the mechanisms of aquaporin subcellular localization, transport selectivity, and gating properties. Although the role of aquaporins in maintaining the plant water status has been addressed, the interactions between plant aquaporins and mineral nutrients remain largely unknown. This review highlights the roles of various aquaporin orthologues in mineral nutrient uptake and transport, as well as the regulatory effects of mineral nutrients on aquaporin expression and activity, and an integrated link between aquaporins and mineral nutrient metabolism was identified. PMID:27483251

  14. The Interactions of Aquaporins and Mineral Nutrients in Higher Plants

    PubMed Central

    Wang, Min; Ding, Lei; Gao, Limin; Li, Yingrui; Shen, Qirong; Guo, Shiwei

    2016-01-01

    Aquaporins, major intrinsic proteins (MIPs) present in the plasma and intracellular membranes, facilitate the transport of small neutral molecules across cell membranes in higher plants. Recently, progress has been made in understanding the mechanisms of aquaporin subcellular localization, transport selectivity, and gating properties. Although the role of aquaporins in maintaining the plant water status has been addressed, the interactions between plant aquaporins and mineral nutrients remain largely unknown. This review highlights the roles of various aquaporin orthologues in mineral nutrient uptake and transport, as well as the regulatory effects of mineral nutrients on aquaporin expression and activity, and an integrated link between aquaporins and mineral nutrient metabolism was identified. PMID:27483251

  15. Understanding molecular mechanism of higher plant plasticity under abiotic stress.

    PubMed

    Shao, Hong-Bo; Guo, Qing-Jie; Chu, Li-Ye; Zhao, Xi-Ning; Su, Zhong-Liang; Hu, Ya-Chen; Cheng, Jiang-Feng

    2007-01-15

    Higher plants play the most important role in keeping a stable environment on the earth, which regulate global circumstances in many ways in terms of different levels (molecular, individual, community, and so on), but the nature of the mechanism is gene expression and control temporally and spatially at the molecular level. In persistently changing environment, there are many adverse stress conditions such as cold, drought, salinity and UV-B (280-320 mm), which influence plant growth and crop production greatly. Plants differ from animals in many aspects, but the important may be that plants are more easily influenced by environment than animals. Plants have a series of fine mechanisms for responding to environmental changes, which has been established during their long-period evolution and artificial domestication. These mechanisms are involved in many aspects of anatomy, physiology, biochemistry, genetics, development, evolution and molecular biology, in which the adaptive machinery related to molecular biology is the most important. The elucidation of it will extremely and purposefully promote the sustainable utilization of plant resources and make the best use of its current potential under different scales. This molecular mechanism at least include environmental signal recognition (input), signal transduction (many cascade biochemical reactions are involved in this process), signal output, signal responses and phenotype realization, which is a multi-dimensional network system and contain many levels of gene expression and regulation. We will focus on the molecular adaptive machinery of higher plant plasticity under abiotic stresses. PMID:16914294

  16. Regulation of cell division in higher plants. Progress report

    SciTech Connect

    Jacobs, T.W.

    1992-07-01

    Cell division is arguably the most fundamental of all developmental processes. In higher plants, mitotic activity is largely confined to foci of patterned cell divisions called meristems. From these perpetually embryonic tissues arise the plant`s essential organs of light capture, support, protection and reproduction. Once an adequate understanding of plant cell mitotic regulation is attained, unprecedented opportunities will ensue for analyzing and genetically controlling diverse aspects of development, including plant architecture, leaf shape, plant height, and root depth. The mitotic cycle in a variety of model eukaryotic systems in under the control of a regulatory network of striking evolutionary conservation. Homologues of the yeast cdc2 gene, its catalytic product, p34, and the cyclin regulatory subunits of the MPF complex have emerged as ubiquitous mitotic regulators. We have cloned cdc2-like and cyclin genes from pea. As in other eukaryotic model systems, p34 of Pisum sativum is a subunit of a high molecular weight complex which binds the fission yeast p13 protein and displays histone H1 kinase activity in vitro. Our primary objective in this study is to gain baseline information about the regulation of this higher plant cell division control complex in non-dividing, differentiated cells as well as in synchronous and asynchronous mitotic cells. We are investigating cdc2 and cyclin expression at the levels of protein abundance, protein phosphorylation and quaternary associations.

  17. 97. Catalog B, Higher Plants, 200 2 American Chestnut Tree, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    97. Catalog B, Higher Plants, 200 2 American Chestnut Tree, Negative No. 6032 (Photographer and date unknown) THIS GHOST FOREST OF BLIGHTED CHESTNUTS ONCE STOOD APPROXIMATELY AT THE LOCATION OF THE BYRD VISITOR CENTER. - Skyline Drive, From Front Royal, VA to Rockfish Gap, VA , Luray, Page County, VA

  18. Cellular Mechanisms of Gravitropic Response in Higher Plants

    NASA Astrophysics Data System (ADS)

    Medvedev, Sergei; Smolikova, Galina; Pozhvanov, Gregory; Suslov, Dmitry

    The evolutionary success of land plants in adaptation to the vectorial environmental factors was based mainly on the development of polarity systems. In result, normal plant ontogenesis is based on the positional information. Polarity is a tool by which the developing plant organs and tissues are mapped and the specific three-dimensional structure of the organism is created. It is due to their polar organization plants are able to orient themselves relative to the gravity vector and different vectorial cues, and to respond adequately to various stimuli. Gravitation is one of the most important polarized environmental factor that guides the development of plant organisms in space. Every plant can "estimate" its position relative to the gravity vector and correct it, if necessary, by means of polarized growth. The direction and the magnitude of gravitational stimulus are constant during the whole plant ontogenesis. The key plant response to the action of gravity is gravitropism, i.e. the directed growth of organs with respect to the gravity vector. This response is a very convenient model to study the mechanisms of plant orientation in space. The present report is focused on the main cellular mechanisms responsible for graviropic bending in higher plants. These mechanisms and structures include electric polarization of plant cells, Ca ({2+) }gradients, cytoskeleton, G-proteins, phosphoinositides and the machinery responsible for asymmetric auxin distribution. Those mechanisms tightly interact demonstrating some hierarchy and multiple feedbacks. The Ca (2+) gradients provide the primary physiological basis of polarity in plant cells. Calcium ions influence on the bioelectric potentials, the organization of actin cytoskeleton, the activity of Ca (2+) -binding proteins and Ca (2+) -dependent protein kinases. Protein kinases modulate transcription factors activity thereby regulating the gene expression and switching the developmental programs. Actin cytoskeleton affects

  19. Enhanced bioremediation of petroleum contaminated soils with higher plants

    SciTech Connect

    Schwab, A.P.; Banks, M.K.

    1996-10-01

    Introduction of higher plants into a bioremediation system can enhance degradation of total petroleum hydrocarbons and target compounds, particularly relatively immobile and recalcitrant organic molecules. Over the past several years, an interdisciplinary team of civil engineers, chemical engineers, soil chemists, soil microbiologists, and plant scientists at Kansas State University have been studying phytoremediation systems. Greenhouse experiments have focused on selecting plants that are most adapted to degrading target compounds and to surviving in soils highly contaminated with petroleum hydrocarbons. Plant species do not seem to differ in their ability to aid in the decomposition of pyrene and anthracene, but benzo[a]pyrene is much more difficult to degrade. Most species are ineffective in enhancing the degradation of benzo[a]pyrene. Four field studies have been initiated in California, Texas, New Jersey, and Virginia to test some of our greenhouse observations.

  20. Progress of targeted genome modification approaches in higher plants.

    PubMed

    Cardi, Teodoro; Neal Stewart, C

    2016-07-01

    Transgene integration in plants is based on illegitimate recombination between non-homologous sequences. The low control of integration site and number of (trans/cis)gene copies might have negative consequences on the expression of transferred genes and their insertion within endogenous coding sequences. The first experiments conducted to use precise homologous recombination for gene integration commenced soon after the first demonstration that transgenic plants could be produced. Modern transgene targeting categories used in plant biology are: (a) homologous recombination-dependent gene targeting; (b) recombinase-mediated site-specific gene integration; (c) oligonucleotide-directed mutagenesis; (d) nuclease-mediated site-specific genome modifications. New tools enable precise gene replacement or stacking with exogenous sequences and targeted mutagenesis of endogeneous sequences. The possibility to engineer chimeric designer nucleases, which are able to target virtually any genomic site, and use them for inducing double-strand breaks in host DNA create new opportunities for both applied plant breeding and functional genomics. CRISPR is the most recent technology available for precise genome editing. Its rapid adoption in biological research is based on its inherent simplicity and efficacy. Its utilization, however, depends on available sequence information, especially for genome-wide analysis. We will review the approaches used for genome modification, specifically those for affecting gene integration and modification in higher plants. For each approach, the advantages and limitations will be noted. We also will speculate on how their actual commercial development and implementation in plant breeding will be affected by governmental regulations. PMID:27025856

  1. The Relevance of Higher Plants in Lead Compound Discovery Programs⊥

    PubMed Central

    Kinghorn, A. Douglas; Pan, Li; Fletcher, Joshua N.; Chai, Heebyung

    2011-01-01

    Along with compounds from terrestrial microorganisms, the constituents of higher plants have provided a substantial number of the natural product-derived drugs used currently in western medicine. Interest in the elucidation of new structures of the secondary metabolite constituents of plants has remained high among the natural products community over the first decade of the 21st century, particularly of species that are used in systems of traditional medicine or are utilized as botanical dietary supplements. In this review, progress made in the senior author’s laboratory in research work on naturally occurring sweeteners and other taste-modifying substances and on potential anticancer agents from tropical plants will be described. PMID:21650152

  2. Early diagenetic transformation of higher-plant triterpenoids in deep-sea sediments from Baffin Bay

    NASA Astrophysics Data System (ADS)

    ten Haven, H. L.; Peakman, T. M.; Rullkötter, J.

    1992-05-01

    A sediment sequence of early Miocene to Holocene from Ocean Drilling Program Site 645 in central Baffin Bay was found to contain abundant triterpenoids of higher-plant origin including monodesmethyl derivatives and other oxidative degradation products. 24-nor-triterpenoids of the oleanene, ursene, and lupane series were found in the nonaromatic hydrocarbon and alcohol fractions of the sediment extracts. Other diagenetic transformation products included 24,28- dinor-olean-17-ene and 24- nor-urs-12-en-1 1-one as well as their tentatively identified des-A counterparts. The identification of these novel degradation products was confirmed by synthesis of a suite of reference compounds. The simple reaction sequence applied to obtain 24- nor-urs-12-ene from 3α-acetoxyurs-12-en-24-oic acid is likely to happen in a similar manner during early diagenesis of organic matter in nature. These results have implications for the understanding of the diagenetic reaction sequence leading to the formation of other demethylated triterpenoids of terrigenous origin (e.g., 24,28- dinor-lupanes). 28,30- dinor-17α-hopane is sometimes the dominant hydrocarbon in the most deeply buried samples. Its co-occurrence with higher plant triterpenoids and the low abundance of other regular hopanoids is not considered an indication, however, that 28,30 dinor-17α-hopane is derived from a higher plant precursor molecule. It is suggested that two independent sedimentary processes are responsible for the presence of the two types of demethylated triterpenoids observed in Baffin Bay sediments.

  3. Experimental determination of magnesium isotope fractionation during higher plant growth

    NASA Astrophysics Data System (ADS)

    Bolou-Bi, Emile B.; Poszwa, Anne; Leyval, Corinne; Vigier, Nathalie

    2010-05-01

    Two higher plant species (rye grass and clover) were cultivated under laboratory conditions on two substrates (solution, phlogopite) in order to constrain the corresponding Mg isotope fractionations during plant growth and Mg uptake. We show that bulk plants are systematically enriched in heavy isotopes relative to their nutrient source. The Δ 26Mg plant-source range from 0.72‰ to 0.26‰ for rye grass and from 1.05‰ to 0.41‰ for clover. Plants grown on phlogopite display Mg isotope signatures (relative to the Mg source) ˜0.3‰ lower than hydroponic plants. For a given substrate, rye grass display lower δ 26Mg (by ˜0.3‰) relative to clover. Magnesium desorbed from rye grass roots display a δ 26Mg greater than the nutrient solution. Adsorption experiments on dead and living rye grass roots also indicate a significant enrichment in heavy isotopes of the Mg adsorbed on the root surface. Our results indicate that the key processes responsible for heavy isotope enrichment in plants are located at the root level. Both species also exhibit an enrichment in light isotopes from roots to shoots (Δ 26Mg leaf-root = -0.65‰ and -0.34‰ for rye grass and clover grown on phlogopite respectively, and Δ 26Mg leaf-root of -0.06‰ and -0.22‰ for the same species grown hydroponically). This heavy isotope depletion in leaves can be explained by biological processes that affect leaves and roots differently: (1) organo-Mg complex (including chlorophyll) formation, and (2) Mg transport within plant. For both species, a positive correlation between δ 26Mg and K/Mg was observed among the various organs. This correlation is consistent with the link between K and Mg internal cycles, as well as with formation of organo-magnesium compounds associated with enrichment in heavy isotopes. Considering our results together with the published range for δ 26Mg of natural plants and rivers, we estimate that a significant change in continental vegetation would induce a change of

  4. Simulation of variation potential in higher plant cells.

    PubMed

    Sukhov, Vladimir; Akinchits, Elena; Katicheva, Lyubov; Vodeneev, Vladimir

    2013-04-01

    Variation potential (VP), a propagating electrical signal unique to plants, induces a number of changes in many physiological processes. However, the mechanisms of its generation and propagation are still under discussion and require experimental and theoretical analysis, including VP simulations. The mathematical model for VP formation in plants has been worked out and is based on our previous description of electrophysiological processes in higher plant cells, including plasma membrane ion transport systems (K(+), Cl(-) and Ca(2+) channels, H(+) and Ca(2+)-ATPase, 2H(+)/Cl(-) symporter and H(+)/K(+) antiporter) and their regulation, ion concentration changes in cells and extracellular spaces and buffers in cytoplasm and apoplast. In addition, the VP model takes into account wound substance diffusion, which is described by a one-dimensional diffusion equation, and ligand-gated Ca(2+) channels, which are activated by this substance. The VP model simulates the experimental dependence of amplitude, velocity and shape of VP on the distance from the wounding site and describes the influence of metabolic inhibitors, divalent cation chelators and anion channel blockers on the generation of this electrical reaction, as shown in experiments. Thus, our model favorably simulates VP in plants and theoretically supports the role of wound substance diffusion and Ca(2+) influx in VP development. PMID:23417063

  5. The trafficking of the cellulose synthase complex in higher plants

    PubMed Central

    Bashline, Logan; Li, Shundai; Gu, Ying

    2014-01-01

    Background Cellulose is an important constituent of plant cell walls in a biological context, and is also a material commonly utilized by mankind in the pulp and paper, timber, textile and biofuel industries. The biosynthesis of cellulose in higher plants is a function of the cellulose synthase complex (CSC). The CSC, a large transmembrane complex containing multiple cellulose synthase proteins, is believed to be assembled in the Golgi apparatus, but is thought only to synthesize cellulose when it is localized at the plasma membrane, where CSCs synthesize and extrude cellulose directly into the plant cell wall. Therefore, the delivery and endocytosis of CSCs to and from the plasma membrane are important aspects for the regulation of cellulose biosynthesis. Scope Recent progress in the visualization of CSC dynamics in living plant cells has begun to reveal some of the routes and factors involved in CSC trafficking. This review highlights the most recent major findings related to CSC trafficking, provides novel perspectives on how CSC trafficking can influence the cell wall, and proposes potential avenues for future exploration. PMID:24651373

  6. The niche of higher plants: evidence for phylogenetic conservatism.

    PubMed Central

    Prinzing, A.; Durka, W.; Klotz, S.; Brandl, R.

    2001-01-01

    A species' ecological niche depends on the species' adaptations to its present habitat, but also on the legacy from its ancestors. Most authors argue that such a phylogenetic niche conservatism is of minor importance, although no quantitative analyses across a major taxon is available. Higher plants from central Europe offer a unique opportunity for such an exercise, as the niche positions along various environmental gradients are available for most species. We quantified niche conservatism by two approaches. First, we used a phylogenetic tree and quantified the degree of retention of niches across the tree. Depending on the gradient, the values ranged from 0.43 to 0.22. This was significantly greater than the null expectation. Second, we used a taxonomy and quantified the amount of variance among species that could be explained at higher taxonomic levels. The values ranged from 25 to 72%. Again, this was significantly higher than the null expectation. Thus, both approaches indicated a clear niche conservatism. The distribution of conservatism across taxonomic levels differed considerably among environmental gradients. The differences among environmental gradients could be correlated with the palaeoenvironmental conditions during the radiation of the phylogenetic lineages. Thus, niche conservatism among extant plant species may reflect the opportunities of their ancestors during their diversification. PMID:11703879

  7. Cloning higher plants from aseptically cultured tissues and cells

    NASA Technical Reports Server (NTRS)

    Krikorian, A. D.

    1982-01-01

    A review of aseptic culture methods for higher plants is presented, which focuses on the existing problems that limit or prevent the full realization of cloning plants from free cells. It is shown that substantial progress in clonal multiplication has been made with explanted stem tips or lateral buds which can be stimulated to produce numerous precocious axillary branches. These branches can then be separated or subdivided and induced to root in order to yield populations of genetically and phenotypically uniorm plantlets. Similarly, undifferentiated calluses can sometimes be induced to form shoots and/or roots adventitiously. Although the cell culture techniques required to produce somatic embryos are presently rudimentary, steady advances are being made in learning how to stimulate formation of somatic or adventive embryos from totipotent cells grown in suspension cultures. It is concluded that many problems exist in the producing and growing of totipotent or morphogenetically competent cell suspensions, but the potential benefits are great.

  8. Lessons from natural and artificial polyploids in higher plants.

    PubMed

    Hegarty, M; Coate, J; Sherman-Broyles, S; Abbott, R; Hiscock, S; Doyle, J

    2013-01-01

    Polyploidy in higher plants is a major source of genetic novelty upon which selection may act to drive evolution, as evidenced by the widespread success of polyploid species in the wild. However, research into the effects of polyploidy can be confounded by the entanglement of several processes: genome duplication, hybridisation (allopolyploidy is frequent in plants) and subsequent evolution. The discovery of the chemical agent colchicine, which can be used to produce artificial polyploids on demand, has enabled scientists to unravel these threads and understand the complex genomic changes involved in each. We present here an overview of lessons learnt from studies of natural and artificial polyploids, and from comparisons between the 2, covering basic cellular and metabolic consequences through to alterations in epigenetic gene regulation, together with 2 in-depth case studies in Senecio and Glycine. See also the sister article focusing on animals by Arai and Fujimoto in this themed issue. PMID:23816545

  9. Regulating the proton budget of higher plant photosynthesis.

    PubMed

    Avenson, Thomas J; Cruz, Jeffrey A; Kanazawa, Atsuko; Kramer, David M

    2005-07-01

    In higher plant chloroplasts, transthylakoid proton motive force serves both to drive the synthesis of ATP and to regulate light capture by the photosynthetic antenna to prevent photodamage. In vivo probes of the proton circuit in wild-type and a mutant strain of Arabidopsis thaliana show that regulation of light capture is modulated primarily by altering the resistance of proton efflux from the thylakoid lumen, whereas modulation of proton influx through cyclic electron flow around photosystem I is suggested to play a role in regulating the ATP/NADPH output ratio of the light reactions. PMID:15972806

  10. Metabolic engineering of higher plants and algae for isoprenoid production.

    PubMed

    Kempinski, Chase; Jiang, Zuodong; Bell, Stephen; Chappell, Joe

    2015-01-01

    Isoprenoids are a class of compounds derived from the five carbon precursors, dimethylallyl diphosphate, and isopentenyl diphosphate. These molecules present incredible natural chemical diversity, which can be valuable for humans in many aspects such as cosmetics, agriculture, and medicine. However, many terpenoids are only produced in small quantities by their natural hosts and can be difficult to generate synthetically. Therefore, much interest and effort has been directed toward capturing the genetic blueprint for their biochemistry and engineering it into alternative hosts such as plants and algae. These autotrophic organisms are attractive when compared to traditional microbial platforms because of their ability to utilize atmospheric CO2 as a carbon substrate instead of supplied carbon sources like glucose. This chapter will summarize important techniques and strategies for engineering the accumulation of isoprenoid metabolites into higher plants and algae by choosing the correct host, avoiding endogenous regulatory mechanisms, and optimizing potential flux into the target compound. Future endeavors will build on these efforts by fine-tuning product accumulation levels via the vast amount of available "-omic" data and devising metabolic engineering schemes that integrate this into a whole-organism approach. With the development of high-throughput transformation protocols and synthetic biology molecular tools, we have only begun to harness the power and utility of plant and algae metabolic engineering. PMID:25636485

  11. Light regulation of gene expression in higher plants

    SciTech Connect

    Tobin, E.M.; Silverthorne, J.

    1985-01-01

    In this review areas of currently active research are considered which have demonstrated that a plant's response to light involves changes in the expression of specific genes at the level of RNA. The regulation of gene expression by phytochrome and the UV-sensitive photoreceptor have been studied most extensively at the molecular level, and this review particularly focuses on such studies in higher plants. Some of the observations made on the differences in gene expression between light-grown and dark-grown plants are also included, although the photoreceptor(s) responsible for the differences may not have been ascertained. In some of these cases, phytochrome involvement has been or may be demonstrated in later studies, while in others the observed differences may be a result of the action of other photoreceptors or of multiple light-affected processes. One such process is the development of chloroplasts, a major developmental step triggered by light in angiosperms. In addition, many of the genes whose expression is changed by light and which have been studied at a molecular level encode chloroplast proteins. 156 references.

  12. Distribution, congruence, and hotspots of higher plants in China

    PubMed Central

    Zhao, Lina; Li, Jinya; Liu, Huiyuan; Qin, Haining

    2016-01-01

    Identifying biodiversity hotspots has become a central issue in setting up priority protection areas, especially as financial resources for biological diversity conservation are limited. Taking China’s Higher Plants Red List (CHPRL), including Bryophytes, Ferns, Gymnosperms, Angiosperms, as the data source, we analyzed the geographic patterns of species richness, endemism, and endangerment via data processing at a fine grid-scale with an average edge length of 30 km based on three aspects of richness information: species richness, endemic species richness, and threatened species richness. We sought to test the accuracy of hotspots used in identifying conservation priorities with regard to higher plants. Next, we tested the congruence of the three aspects and made a comparison of the similarities and differences between the hotspots described in this paper and those in previous studies. We found that over 90% of threatened species in China are concentrated. While a high spatial congruence is observed among the three measures, there is a low congruence between two different sets of hotspots. Our results suggest that biodiversity information should be considered when identifying biological hotspots. Other factors, such as scales, should be included as well to develop biodiversity conservation plans in accordance with the region’s specific conditions. PMID:26750244

  13. Diagenesis of higher plant triterpenes in evaporitic sediments

    SciTech Connect

    Poinsot, J.; Adam, P.; Trendel, J.M.

    1995-12-31

    Several samples from a Tertiary carbonated evaporitic series (Sainte-Cecile, Camargue, France) were investigated. Their analysis revealed a high abundance of new or uncommon hydrocarbons and organic S compounds related to higher plant triterpenes. Several of them, in particular, 12,29-cyclolupa-12,18,20(29)-triene 1, could be positively identified. These triterpenoids are generally absent from non-evaporitic sediments which contain essentially aromatic triterpenoids resulting from microbially mediated aromatization processes starting in ring A (or in ring B when preceded by the loss of ring A). The uncommon transformations undergone by higher plant triterpenes in the highly anoxic sediments from Sainte-Cecile are specific for each series of triterpenes (i.e., oleanane, ursane, lupane) and are probably linked with the rapid disappearance of the functionality located in ring A by reduction or by the incorporation of the triterpenes in S-rich macromolecules by reaction with inorganic S species. These biological markers represent new source parameters which may be quite useful as indicators of terrestrial inputs in evaporitic deposits. 33 refs., 10 figs.

  14. 5-Oxoprolinase (l-Pyroglutamate Hydrolase) in Higher Plants

    PubMed Central

    Mazelis, Mendel; Creveling, Richard K.

    1978-01-01

    5-Oxoprolinase has been found to be widely distributed in higher plants. This enzyme catalyzes the ATP-dependent hydrolysis of 5-oxo-l-proline (l-pyrollidone carboxylate, l-pyroglutamate) to glutamate. The enzyme has been purified almost 60 fold from wheat germ (Triticum aestivum L). This enzyme requires a divalent cation, either Mn2+ or Mg2+, and a combination of both appears to be the most effective. There is also an absolute requirement for a monovalent cation best fulfilled by either NH4+ or K+. The Km for ATP is 0.4 mm and for 5-oxo-l-proline is 14 μm. A small amount of activity is observed when other purine nucleotides such as ITP and GTP replace ATP. The substitution of the pyrimidine nucleotides CTP and UTP for ATP yield almost completely inactive preparations. The enzyme appears to have an active sulfhydryl group since there is an increase in activity in the presence of dithioerythritol. Preincubation with reagents such as N-ethylmaleimide or iodoacetamide lead to complete inactivation. The presence of this enzyme leads to the speculation of the possible presence of a γ-glutamyl cycle in higher plants. PMID:16660609

  15. Distribution, congruence, and hotspots of higher plants in China.

    PubMed

    Zhao, Lina; Li, Jinya; Liu, Huiyuan; Qin, Haining

    2016-01-01

    Identifying biodiversity hotspots has become a central issue in setting up priority protection areas, especially as financial resources for biological diversity conservation are limited. Taking China's Higher Plants Red List (CHPRL), including Bryophytes, Ferns, Gymnosperms, Angiosperms, as the data source, we analyzed the geographic patterns of species richness, endemism, and endangerment via data processing at a fine grid-scale with an average edge length of 30 km based on three aspects of richness information: species richness, endemic species richness, and threatened species richness. We sought to test the accuracy of hotspots used in identifying conservation priorities with regard to higher plants. Next, we tested the congruence of the three aspects and made a comparison of the similarities and differences between the hotspots described in this paper and those in previous studies. We found that over 90% of threatened species in China are concentrated. While a high spatial congruence is observed among the three measures, there is a low congruence between two different sets of hotspots. Our results suggest that biodiversity information should be considered when identifying biological hotspots. Other factors, such as scales, should be included as well to develop biodiversity conservation plans in accordance with the region's specific conditions. PMID:26750244

  16. Distribution, congruence, and hotspots of higher plants in China

    NASA Astrophysics Data System (ADS)

    Zhao, Lina; Li, Jinya; Liu, Huiyuan; Qin, Haining

    2016-01-01

    Identifying biodiversity hotspots has become a central issue in setting up priority protection areas, especially as financial resources for biological diversity conservation are limited. Taking China’s Higher Plants Red List (CHPRL), including Bryophytes, Ferns, Gymnosperms, Angiosperms, as the data source, we analyzed the geographic patterns of species richness, endemism, and endangerment via data processing at a fine grid-scale with an average edge length of 30 km based on three aspects of richness information: species richness, endemic species richness, and threatened species richness. We sought to test the accuracy of hotspots used in identifying conservation priorities with regard to higher plants. Next, we tested the congruence of the three aspects and made a comparison of the similarities and differences between the hotspots described in this paper and those in previous studies. We found that over 90% of threatened species in China are concentrated. While a high spatial congruence is observed among the three measures, there is a low congruence between two different sets of hotspots. Our results suggest that biodiversity information should be considered when identifying biological hotspots. Other factors, such as scales, should be included as well to develop biodiversity conservation plans in accordance with the region’s specific conditions.

  17. Higher Plant Cytochrome b5 Polypeptides Modulate Fatty Acid Desaturation

    PubMed Central

    Kumar, Rajesh; Tran, Lam-Son Phan; Neelakandan, Anjanasree K.; Nguyen, Henry T.

    2012-01-01

    Background Synthesis of polyunsaturated fatty acids (PUFAs) in the endoplasmic reticulum of plants typically involves the fatty acid desaturases FAD2 and FAD3, which use cytochrome b5 (Cb5) as an electron donor. Higher plants are reported to have multiple isoforms of Cb5, in contrast to a single Cb5 in mammals and yeast. Despite the wealth of information available on the roles of FAD2 and FAD3 in PUFA synthesis, information regarding the contributions of various Cb5 isoforms in desaturase-mediated reactions is limited. Results The present functional characterization of Cb5 polypeptides revealed that all Arabidopsis Cb5 isoforms are not similarly efficient in ω-6 desaturation, as evidenced by significant variation in their product outcomes in yeast-based functional assays. On the other hand, characterization of Cb5 polypeptides of soybean (Glycine max) suggested that similar ω-6 desaturation efficiencies were shared by various isoforms. With regard to ω-3 desaturation, certain Cb5 genes of both Arabidopsis and soybean were shown to facilitate the accumulation of more desaturation products than others when co-expressed with their native FAD3. Additionally, similar trends of differential desaturation product accumulation were also observed with most Cb5 genes of both soybean and Arabidopsis even if co-expressed with non-native FAD3. Conclusions The present study reports the first description of the differential nature of the Cb5 genes of higher plants in fatty acid desaturation and further suggests that ω-3/ω-6 desaturation product outcome is determined by the nature of both the Cb5 isoform and the fatty acid desaturases. PMID:22384013

  18. [90Sr and 137Cs in higher aquatic plants of the Chernobyl nuclear plant exlusion zone

    PubMed

    Gudkov, D I; Derevets, V V; Kuz'menko, M I; Nazarov, A B

    2001-01-01

    The content of radionuclides 90Sr and 137Cs in higher aquatic plants of water objects within Chernobyl NPP exclusion zone has been analysed. Biodiversity of phytocenose was studied and species-indicators of radioactive contamination were revealed. The seasonal dynamics of radionuclide content in macrophytes was studied and the role of main aquatic plant clumps in processes of 137Cs and 90Sr distribution in abiotic component of biohydrocenose was demonstrated. PMID:11402559

  19. b-Type Cytochromes in Higher Plant Plasma Membranes 1

    PubMed Central

    Asard, Han; Venken, Mireille; Caubergs, Roland; Reijnders, Willem; Oltmann, Fred L.; De Greef, Jan A.

    1989-01-01

    The composition and characteristics of b-type cytochromes from higher plant plasma membranes, purified using aqueous two-phase partitioning, were investigated. At least three different cytochromes were identified by their wavelength maxima and redox midpoint potentials (E0′). Cytochrome b-560.7 (E0′ from + 110 to + 160 millivolts) was present in zucchini (Cucurbita pepo) hypocotyls and bean (Phaseolus vulgaris L.) hooks, although in different concentrations. The main component in cauliflower (Brassica oleracea L.) inflorescences (cytochrome b-558.8) is probably functionally similar to this cytochrome. The plasma membrane generally contains two to three cytochrome species. However, the occurrence and concentrations were species dependent. The high potential cytochrome can be reduced by ascorbate but not NADH, and may be involved in blue light perception. PMID:16666854

  20. Variation potential in higher plants: Mechanisms of generation and propagation

    PubMed Central

    Vodeneev, Vladimir; Akinchits, Elena; Sukhov, Vladimir

    2015-01-01

    Long-distance intercellular electrical signals, including variation potential (VP) in higher plants, are a potential mechanism of coordinate functional responses in different plant cells under action of stressors. VP, which is caused by damaging factors (e.g., heating, crushing), is transient depolarization with an irregular shape. It can include a long-term depolarization and fast impulse depolarization (‘AP-like’ spikes). Mechanisms of VP generation and propagation are still under investigation. It is probable that VP is a local electrical response induced by propagation of hydraulic wave and (or) chemical agent. Both hypotheses are based on numerous experimental results but they predict VP velocities which are not in a good accordance with speed of variation potential propagation. Thus combination of hydraulic and chemical signals is the probable mechanism of VP propagation. VP generation is traditionally connected with transient H+-ATPase inactivation, but AP-like spikes are also connected with passive ions fluxes. Ca2+ influx is a probable mechanism which triggers H+-ATPase inactivation and ions channels activation at VP. PMID:26313506

  1. Mitochondrial glycolate oxidation contributes to photorespiration in higher plants.

    PubMed

    Niessen, Markus; Thiruveedhi, Krishnaveni; Rosenkranz, Ruben; Kebeish, Rashad; Hirsch, Heinz-Josef; Kreuzaler, Fritz; Peterhänsel, Christoph

    2007-01-01

    The oxidation of glycolate to glyoxylate is an important reaction step in photorespiration. Land plants and charophycean green algae oxidize glycolate in the peroxisome using oxygen as a co-factor, whereas chlorophycean green algae use a mitochondrial glycolate dehydrogenase (GDH) with organic co-factors. Previous analyses revealed the existence of a GDH in the mitochondria of Arabidopsis thaliana (AtGDH). In this study, the contribution of AtGDH to photorespiration was characterized. Both RNA abundance and mitochondrial GDH activity were up-regulated under photorespiratory growth conditions. Labelling experiments indicated that glycolate oxidation in mitochondrial extracts is coupled to CO(2) release. This effect could be enhanced by adding co-factors for aminotransferases, but is inhibited by the addition of glycine. T-DNA insertion lines for AtGDH show a drastic reduction in mitochondrial GDH activity and CO(2) release from glycolate. Furthermore, photorespiration is reduced in these mutant lines compared with the wild type, as revealed by determination of the post-illumination CO(2) burst and the glycine/serine ratio under photorespiratory growth conditions. The data show that mitochondrial glycolate oxidation contributes to photorespiration in higher plants. This indicates the conservation of chlorophycean photorespiration in streptophytes despite the evolution of leaf-type peroxisomes. PMID:17595195

  2. Functional architecture of higher plant photosystem II supercomplexes

    PubMed Central

    Caffarri, Stefano; Kouřil, Roman; Kereïche, Sami; Boekema, Egbert J; Croce, Roberta

    2009-01-01

    Photosystem II (PSII) is a large multiprotein complex, which catalyses water splitting and plastoquinone reduction necessary to transform sunlight into chemical energy. Detailed functional and structural studies of the complex from higher plants have been hampered by the impossibility to purify it to homogeneity. In this work, homogeneous preparations ranging from a newly identified particle composed by a monomeric core and antenna proteins to the largest C2S2M2 supercomplex were isolated. Characterization by biochemical methods and single particle electron microscopy allowed to relate for the first time the supramolecular organization to the protein content. A projection map of C2S2M2 at 12 Å resolution was obtained, which allowed determining the location and the orientation of the antenna proteins. Comparison of the supercomplexes obtained from WT and Lhcb-deficient plants reveals the importance of the individual subunits for the supramolecular organization. The functional implications of these findings are discussed and allow redefining previous suggestions on PSII energy transfer, assembly, photoinhibition, state transition and non-photochemical quenching. PMID:19696744

  3. Need for higher fuel burnup at the Hatch Plant

    SciTech Connect

    Beckhman, J.T.

    1996-03-01

    Hatch is a BWR 4 and has been in operation for some time. The first unit became commercial about 1975. Obtaining higher burnups, or higher average discharge exposures, is nothing new at Hatch. Since we have started, the discharge exposure of the plant has increased. Now, of course, we are not approaching the numbers currently being discussed but, the average discharge exposure has increased from around 20,000 MWD/MTU in the early to mid-1980s to 34,000 MWD/MTU in 1994, I am talking about batch average values. There are also peak bundle and peak rod values. You will have to make the conversions if you think in one way or the other because I am talking in batch averages. During Hatch`s operating history we have had some problems with fuel failure. Higher burnup fuel raises a concern about how much fuel failure you are going to have. Fuel failure is, of course, an economic issue with us. Back in the early 1980s, we had a problem with crud-induced localized corrosion, known as CILC. We have gotten over that, but we had some times when it was up around 27 fuel failures a year. That is not a pleasant time to live through because it is not what you want from an economic viewpoint or any other. We have gotten that down. We have had some fuel failures recently, but they have not been related to fuel burnup or to corrosion. In fact, the number of failures has decreased from the early 1980s to the 90s even though burnup increased during that time. The fuel failures are more debris-related-type failures. In addition to increasing burnups, utilities are actively evaluating or have already incorporated power uprate and longer fuel cycles (e.g., 2-year cycles). The goal is to balance out the higher power density, longer cycles, higher burnup, and to have no leakers. Why do we as an industry want to have higher burnup fuel? That is what I want to tell you a little bit about.

  4. The stoichiometry of the two photosystems in higher plants revisited.

    PubMed

    Fan, Da-Yong; Hope, Alexander B; Smith, Paul J; Jia, Husen; Pace, Ronald J; Anderson, Jan M; Chow, Wah Soon

    2007-08-01

    The stoichiometry of Photosystem II (PSII) to Photosystem I (PSI) reaction centres in spinach leaf segments was determined by two methods, each capable of being applied to monitor the presence of both photosystems in a given sample. One method was based on a fast electrochromic (EC) signal, which in the millisecond time scale represents a change in the delocalized electric potential difference across the thylakoid membrane resulting from charge separation in both photosystems. This method was applied to leaf segments, thus avoiding any potential artefacts associated with the isolation of thylakoid membranes. Two variations of this method, suppressing PSII activity by prior photoinactivation (in spinach and poplar leaf segments) or suppressing PSI by photo-oxidation of P700 (the chlorophyll dimer in PSI) with background far-red light (in spinach, poplar and cucumber leaf segments), each gave the separate contribution of each photosystem to the fast EC signal; the PSII/PSI stoichiometry obtained by this method was in the range 1.5-1.9 for the three plant species, and 1.5-1.8 for spinach in particular. A second method, based on electron paramagnetic resonance (EPR), gave values in a comparable range of 1.7-2.1 for spinach. A third method, which consisted of separately determining the content of functional PSII in leaf segments by the oxygen yield per single turnover-flash and that of PSI by photo-oxidation of P700 in thylakoids isolated from the corresponding leaves, gave a PSII/PSI stoichiometry (1.5-1.7) that was consistent with the above values. It is concluded that the ratio of PSII to PSI reaction centres is considerably higher than unity in typical higher plants, in contrast to a surprisingly low PSII/PSI ratio of 0.88, determined by EPR, that was reported for spinach grown in a cabinet under far-red-deficient light in Sweden [Danielsson et al. (2004) Biochim. Biophys. Acta 1608: 53-61]. We suggest that the low PSII/PSI ratio in the Swedish spinach, grown in far

  5. Cellulose microfibril assembly and orientation in higher plant cells

    SciTech Connect

    Mueller, S.C.; Maclachlan, G.A.; Brown, R.M. Jr.

    1983-01-01

    Freeze-fractured plasma membranes of seedlings of Zea mays L., Burpee's Snowcross, and Pisum sativum L., variety Alsaka, contain terminal complex structures and the impressions of microfibrils from the newest cell wall layer.Terminal complex subunits are on the exoplasmic fracture (EF) face, and rosette subunits are on the protoplasmic fracture (PF) face of the membrane. The association of terminal complexes and rosettes with microfibril tips and their association with newly deposited groups of microfibrils is indirect evidence for their role in microfibril assembly. Microtubules may be responsible for certain orientations of microfibrils, particularly the formation of bands of microfibrils in newly deposited wall layers. However, microfibril orienting mechanisms are more complex, involving factors still present during colchicine treatment. Since UDP-glucose is thought to be a precursor of cellulose microfibrils in higher plant cells, EM radioautography was used to determine the site of incorporation of glucose. However, under the conditions used, glucose was only incorporated from UDP-glucose at the surface of cut or damaged pea stem cells, i.e., in vitro. Thus, incorporation of glucose from UDP-glucose was not useful for probing the patterns of cellulose microfibril synthesis in vivo. 18 references, 8 figures.

  6. The Biosynthesis of δ-Aminolevulinic Acid in Higher Plants

    PubMed Central

    Beale, Samuel I.; Castelfranco, Paul A.

    1974-01-01

    δ-Aminolevulinic acid dehydrase activity in cucumber (Cucumis sativus L. var. Alpha green) cotyledons did not change as the tissue was allowed to green for 24 hours. δ-Aminolevulinic acid accumulated in greening cucumber cotyledons, and barley (Hordeum sativum L. var. Numar) and bean (Phaseolus vulgaris L. var. Red Kidney) leaves incubated in the presence of levulinic acid, a specific competitive inhibitor of δ-aminolevulinic acid dehydrase. The rate of δ-aminolevulinic acid accumulation in levulinic acid-treated cucumber cotyledons paralleled the rate of chlorophyll accumulation in the controls, and the quantity of δ-aminolevulinic acid accumulated compensated for the decrease in chlorophyll accumulation. When levulinic acid-treated cucumber cotyledons were returned to darkness, δ-aminolevulinic acid accumulation ceased. δ-Aminolevulinic acid accumulation showed an absolute requirement for oxygen and was inhibited drastically by cyanide and azide, and to a lesser extent by arsenite and malonate. 2,4-Dinitrophenol, 3-(3,4-dichlorophenyl)-1,1-dimethyl urea, sodium fluoroacetate, and hydroxylamine hydrochloride showed no effect under the conditions tested. Freezing and thawing of the tissue completely prevented the accumulation of δ-aminolevulinic acid. The findings of this investigation are consistent with the hypothesis that δ-aminolevulinic acid is a chlorophyll precursor in higher plants, and that chlorophyll biosynthesis is regulated at the level of the formation of δ-aminolevulinic acid. PMID:16658693

  7. Monoclonal antibodies to the alternative oxidase of higher plant mitochondria

    SciTech Connect

    Elthon, T.E.; Nickels, R.L.; McIntosh, L. )

    1989-04-01

    The higher plant mitochondrial electron transport chain contains, in addition to the cytochrome chain which terminates with cytochrome oxidase, an alternative pathway that terminates with an alternative oxidase. The alternative oxidase of Sauromatum guttatum Schott has recently been identified as a cluster of proteins with apparent M{sub r} of 37, 36, and 35 kilodaltons (kD). Monoclonal antibodies have now been prepared to these proteins and designated as AOA (binding all three proteins of the alternative oxidase cluster), AOU (binding the upper or 37 kD protein), and AOL (binding the lower or 36 and 35 kD proteins). All three antibodies bind to their respective alternative oxidase proteins whether the proteins are in their native or denatured states. AOA and AOU inhibit alternative oxidase activity around 49%, whereas AOL inhibits activity only 14%. When coupled individually to Sepharose 4B, all three monoclonal resins were capable of retaining the entire cluster of alternative oxidase proteins, suggesting that these proteins are physically associated in some manner. The monoclonals were capable of binding similar mitochondrial proteins in a number of thermogenic and nonthermogenic species, indicating that they will be useful in characterizing and purifying the alternative oxidase of different systems. The ability of the monoclonal-Sepharose 4B resins to retain the cluster of previously identified alternative oxidase proteins, along with the inhibition of alternative oxidase activity by these monoclonals, supports the role of these proteins in constituting the alternative oxidase.

  8. Plastid DNA polymerases from higher plants, Arabidopsis thaliana

    SciTech Connect

    Mori, Yoko; Kimura, Seisuke; Saotome, Ai; Kasai, Nobuyuki; Sakaguchi, Norihiro; Uchiyama, Yukinobu; Ishibashi, Toyotaka; Yamamoto, Taichi; Chiku, Hiroyuki; Sakaguchi, Kengo . E-mail: kengo@rs.noda.sut.ac.jp

    2005-08-19

    Previously, we described a novel DNA polymerase, designated as OsPolI-like, from rice. The OsPolI-like showed a high degree of sequence homology with the DNA polymerase I of cyanobacteria and was localized in the plastid. Here, we describe two PolI-like polymerases, designated as AtPolI-like A and AtPolI-like B, from Arabidopsis thaliana. In situ hybridization analysis demonstrated expression of both mRNAs in proliferating tissues such as the shoot apical meristem. Analysis of the localizations of GFP fusion proteins showed that AtPolI-like A and AtPolI-like B were localized to plastids. AtPolI-like B expression could be induced by exposure to the mutagen H{sub 2}O{sub 2}. These results suggested that AtPolI-like B has a role in the repair of oxidation-induced DNA damage. Our data indicate that higher plants possess two plastid DNA polymerases that are not found in animals and yeasts.

  9. Higher Plants in life support systems: design of a model and plant experimental compartment

    NASA Astrophysics Data System (ADS)

    Hezard, Pauline; Farges, Berangere; Sasidharan L, Swathy; Dussap, Claude-Gilles

    The development of closed ecological life support systems (CELSS) requires full control and efficient engineering for fulfilling the common objectives of water and oxygen regeneration, CO2 elimination and food production. Most of the proposed CELSS contain higher plants, for which a growth chamber and a control system are needed. Inside the compartment the development of higher plants must be understood and modeled in order to be able to design and control the compartment as a function of operating variables. The plant behavior must be analyzed at different sub-process scales : (i) architecture and morphology describe the plant shape and lead to calculate the morphological parameters (leaf area, stem length, number of meristems. . . ) characteristic of life cycle stages; (ii) physiology and metabolism of the different organs permit to assess the plant composition depending on the plant input and output rates (oxygen, carbon dioxide, water and nutrients); (iii) finally, the physical processes are light interception, gas exchange, sap conduction and root uptake: they control the available energy from photosynthesis and the input and output rates. These three different sub-processes are modeled as a system of equations using environmental and plant parameters such as light intensity, temperature, pressure, humidity, CO2 and oxygen partial pressures, nutrient solution composition, total leaf surface and leaf area index, chlorophyll content, stomatal conductance, water potential, organ biomass distribution and composition, etc. The most challenging issue is to develop a comprehensive and operative mathematical model that assembles these different sub-processes in a unique framework. In order to assess the parameters for testing a model, a polyvalent growth chamber is necessary. It should permit a controlled environment in order to test and understand the physiological response and determine the control strategy. The final aim of this model is to have an envi

  10. Lower resistance and higher tolerance of invasive host plants: biocontrol agents reach high densities but exert weak control.

    PubMed

    Wang, Yi; Huang, Wei; Siemann, Evan; Zou, Jianwen; Wheeler, Gregory S; Carrillo, Juli; Ding, Jianqing

    2011-04-01

    Invasive plants often have novel biotic interactions in their introduced ranges. Their defense to herbivory may differ from their native counterparts, potentially influencing the effectiveness of biological control. If invasive plants have decreased resistance but increased tolerance to enemies, insect herbivores may rapidly build up their populations but exert weak control. Moreover, resource availability to plants may affect the efficacy of biological control agents. We tested these predictions using Chinese tallow tree (Triadica sebifera) and two specialist herbivores (Heterapoderopsis bicallosicollis and Gadirtha inexacta) that are candidates for biological control. We performed a pair of field common garden experiments in China in which Triadica seedlings from the native or introduced range were grown in low or high light conditions and subjected to different levels of herbivory by each herbivore in a factorial design. We found that Heterapoderopsis achieved greater densities on tallow trees from the introduced range or when trees were grown in high light conditions. When Gadirtha was raised in the lab on tallow tree foliage we found that it performed better (larger pupal size) when fed foliage from introduced populations. However, introduced populations generally had greater herbivore tolerance such that the impact of each agent on plant performance was lower than on native populations despite higher herbivore loads. Tallow trees grew more slowly and achieved smaller sizes in lower light levels, but the impact of biological control agents was comparable to that found for higher light levels. Plants from introduced populations grew larger than those from native populations in all conditions. Our results suggest that reduced resistance and increased tolerance to herbivory in introduced populations may impede success of biological control programs. Biological control practitioners should include plants from the introduced range in the prerelease evaluation

  11. MICROORGANISMS AND HIGHER PLANTS FOR WASTE WATER TREATMENT

    EPA Science Inventory

    Batch experiments were conducted to compare the waste water treatment efficiencies of plant-free microbial filters with filters supporting the growth of reeds (Phragmites communis), cattail (Typha latifolia), rush (Juncus effusus), and bamboo (Bambusa multiplex). The experimental...

  12. Oil is on the agenda: Lipid turnover in higher plants.

    PubMed

    Kelly, Amélie A; Feussner, Ivo

    2016-09-01

    Lipases hydrolyze ester bonds within lipids. This process is called lipolysis. They are key players in lipid turnover and involved in numerous metabolic pathways, many of which are shared between organisms like the mobilization of neutral or storage lipids or lipase-mediated membrane lipid homeostasis. Some reactions though are predominantly present in certain organisms, such as the production of signaling molecules (endocannabinoids) by diacylglycerol (DAG) and monoacylglycerol (MAG) lipases in mammals and plants or the jasmonate production in flowering plants. This review aims at giving an overview of the different functional classes of lipases and respective well-known activities, with a focus on the most recent findings in plant biology for selected classes. Here we will put an emphasis on the physiological role and contribution of lipases to the turnover of neutral lipids found in seed oil and other vegetative tissue as candidates for increasing the economical values of crop plants. This article is part of a Special Issue entitled: Plant Lipid Biology edited by Kent D. Chapman and Ivo Feussner. PMID:27155216

  13. Metabolism of tryptophol in higher and lower plants.

    PubMed

    Laćan, G; Magnus, V; Simaga, S; Iskrić, S; Hall, P J

    1985-07-01

    Bacteria, thallophytes, and seed plants (107 species), supplied with exogenous indole-3-ethanol (tryptophol), formed one or more of the following metabolites: O-acetyl tryptophol, an unknown tryptophol ester (or a set of structurally closely related esters), tryptophol glucoside, tryptophol galactoside, indole-3-acetic acid (IAA), and indole-3-carboxylic acid. The unknown ester was formed by all species examined; O-acetyl tryptophol appeared sporadically in representatives of most major taxonomic groups. Tryptophol galactoside was found in the algae Chlorella, Euglena, and Ochromonas. The glucoside was formed by many eucaryotic plants, but not by bacteria; it was a significant tryptophol metabolite in vascular plants. IAA, if detectable at all, was usually a minor metabolite, as should be expected, if tryptophol oxidase responds to feedback inhibition by IAA. Indole-3-carboxylic acid, formed by a few fungi and mosses, was the only tryptophol metabolite detected which is likely to be formed via IAA. PMID:16664264

  14. Genotoxic and mutagenic effects of sewage sludge on higher plants.

    PubMed

    Corrêa Martins, Maria Nilza; de Souza, Victor Ventura; Souza, Tatiana da Silva

    2016-02-01

    Sewage treatment yields sludge, which is often used as a soil amendment in agriculture and crop production. Although the sludge contains elevated concentrations of macro and micronutrients, high levels of inorganic and organic compounds with genotoxic and mutagenic properties are present in sludge. Application of sludge in agriculture is a pathway for direct contact of crops to toxic chemicals. The objective of this study was to compile information related to the genotoxic and mutagenic effects of sewage sludge in different plant species. In addition, data are presented on toxicological effects in animals fed with plants grown in soils supplemented with sewage sludge. Despite the benefits of using sewage sludge as organic fertilizer, the data showcased in this review suggest that this residue can induce genetic damage in plants. This review alerts potential risks to health outcomes after the intake of food cultivated in sewage sludge-amended soils. PMID:26643763

  15. Metabolism of Tryptophol in Higher and Lower Plants 1

    PubMed Central

    Laćan, Goran; Magnus, Volker; Šimaga, Šumski; Iskrić, Sonja; Hall, Prudence J.

    1985-01-01

    Bacteria, thallophytes, and seed plants (107 species), supplied with exogenous indole-3-ethanol (tryptophol), formed one or more of the following metabolites: O-acetyl tryptophol, an unknown tryptophol ester (or a set of structurally closely related esters), tryptophol glucoside, tryptophol galactoside, indole-3-acetic acid (IAA), and indole-3-carboxylic acid. The unknown ester was formed by all species examined; O-acetyl tryptophol appeared sporadically in representatives of most major taxonomic groups. Tryptophol galactoside was found in the algae Chlorella, Euglena, and Ochromonas. The glucoside was formed by many eucaryotic plants, but not by bacteria; it was a significant tryptophol metabolite in vascular plants. IAA, if detectable at all, was usually a minor metabolite, as should be expected, if tryptophol oxidase responds to feedback inhibition by IAA. Indole-3-carboxylic acid, formed by a few fungi and mosses, was the only tryptophol metabolite detected which is likely to be formed via IAA. PMID:16664264

  16. Experimental identification of Ca isotopic fractionations in higher plants

    NASA Astrophysics Data System (ADS)

    Cobert, Florian; Schmitt, Anne-Désirée; Bourgeade, Pascale; Labolle, François; Badot, Pierre-Marie; Chabaux, François; Stille, Peter

    2011-10-01

    Hydroponic experiments have been performed in order to identify the co-occurring geochemical and biological processes affecting the Ca isotopic compositions within plants. To test the influence of the Ca concentration and pH of the nutritive solution on the Ca isotopic composition of the different plant organs, four experimental conditions were chosen combining two different Ca concentrations (5 and 60 ppm) and two pHs (4 and 6). The study was performed on rapid growing bean plants in order to have a complete growth cycle. Several organs (root, stem, leaf, reproductive) were sampled at two different growth stages (10 days and 6 weeks of culture) and prepared for Ca isotopic measurements. The results allow to identify three Ca isotopic fractionation levels. The first one takes place when Ca enters the lateral roots, during Ca adsorption on cation-exchange binding sites in the apoplasm. The second one takes place when Ca is bound to the polygalacturonic acids (pectins) of the middle lamella of the xylem cell wall. Finally, the last fractionation occurs in the reproductive organs, also caused by cation-exchange processes with pectins. However, the cell wall structures of these organs and/or number of available exchange sites seem to be different to those of the xylem wall. These three physico-chemical fractionation mechanisms allow to enrich the organs in the light 40Ca isotope. The amplitude of the Ca isotopic fractionation within plant organs is highly dependent on the composition of the nutritive solution: low pH (4) and Ca concentrations (5 ppm) have no effect on the biomass increase of the plants but induce smaller fractionation amplitudes compared to those obtained from other experimental conditions. Thus, Ca isotopic signatures of bean plants are controlled by the external nutritive medium. This study highlights the potential of Ca isotopes to be applied in plant physiology (to identify Ca uptake, circulation and storage mechanisms within plants) and in

  17. Photosynthetic and respiratory activity in germfree higher plant species

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Equipment developed for the study of gas exchange in germfree plants is described. The equipment includes a gas exchange chamber to house the plant under study, a gas feed assembly to introduce and remove gas from the chamber, and a clinostat to rotate the apparatus. Fluorescent and incandescent lights are used to illuminate the chamber and a sealed plastic barrier is used to isolate the potting soil from the chamber atmosphere. The gas outflow from the chamber can be diverted to an infrared CO2 analyzer. The performance of the system was evaluated.

  18. INTERNAL FILTERS: PROSPECTS FOR UV-ACCLIMATION IN HIGHER PLANTS

    EPA Science Inventory

    Wavelength-selective absorption of solar radiation within plant leaves allows penetration of visible radiation (400-700nm) to the chloroplasts, while removing much of the damaging ultraviolet-B (UV-B, 280-320 nm) radiation. Flavonoids are important in this wavelength-selective ab...

  19. The Genes for Cytoplasmic Ribosomal Ribonucleic Acid in Higher Plants

    PubMed Central

    Scott, N. Steele; Ingle, J.

    1973-01-01

    The genes for cytoplasmic ribosomal RNA are partially resolved from the bulk of the DNA by CsCl equilibrium centrifugation. Although in some plants the buoyant density of the ribosomal RNA genes is as expected from the base composition of ribosomal RNA, others show a large discrepancy which cannot be due to the presence of low G-C spacer-DNA. The cross-hybridization observed with 1.3 and 0.7 × 106 molecular weight ribosomal RNAs and DNA, which varies greatly with different plant species, is not due to contamination of the ribosomal RNAs, and is specific for the ribosomal DNA of each species, probably largely restricted to those sequences coding for the two stable ribosomal RNAs. The double reciprocal plot may be used for the extrapolation of saturation values only with caution, because in these cases such plots are not linear over the whole of the hybridization reaction. PMID:16658392

  20. Regulation of cell division in higher plants. Final technical report

    SciTech Connect

    Jacobs, Thomas W.

    2000-02-29

    Research in the latter part of the grant period was divided into two parts: (1) expansion of the macromolecular tool kit for studying plant cell division; (2) experiments in which the roles played by plant cell cycle regulators were to be cast in the light of the emerging yeast and animal cell paradigm for molecular control of the mitotic cycle. The first objectives were accomplished to a very satisfactory degree. With regard to the second part of the project, we were driven to change our objectives for two reasons. First, the families of cell cycle control genes that we cloned encoded such closely related members that the prospects for success at raising distinguishing antisera against each were sufficiently dubious as to be impractical. Epitope tagging is not feasible in Pisum sativum, our experimental system, as this species is not realistically transformable. Therefore, differentiating the roles of diverse cyclins and cyclin-dependent kinases was problematic. Secondly, our procedure for generating mitotically synchronized pea root meristems for biochemical studies was far too labor intensive for the proposed experiments. We therefore shifted our objectives to identifying connections between the conserved proteins of the cell cycle engine and factors that interface it with plant physiology and development. In this, we have obtained some very exciting results.

  1. Final Report for Regulation of Embryonic Development in Higher Plants

    SciTech Connect

    Harada, John J.

    2013-10-22

    The overall goal of the project was to define the cellular processes that underlie embryo development in plants at a mechanistic level. Our studies focused on a critical transcriptional regulator, Arabidopsis LEAFY COTYLEDON (LEC1), that is necessary and sufficient to induce processes required for embryo development. Because LEC1 regulates lipid accumulation during the maturation phase of embryo development, information about LEC1 may be useful in designing approaches to enhance biofuel production in plants. During the tenure of this project, we determined the molecular mechanisms by which LEC1 acts as a transcription factor in embryos. We also identified genes directly regulated by LEC1 and showed that many of these genes are involved in maturation processes. This information has been useful in dissecting the gene regulatory networks controlling embryo development. Finally, LEC1 is a novel isoform of a transcription factor that is conserved among eukaryotes, and LEC1 is active primarily in seeds. Therefore, we determined that the LEC1-type transcription factors first appeared in lycophytes during land plant evolution. Together, this study provides basic information that has implications for biofuel production.

  2. Gravitropism in higher plant shoots. I - A role for ethylene

    NASA Technical Reports Server (NTRS)

    Wheeler, Raymond M.; Salisbury, Frank B.

    1981-01-01

    Two inhibitors of ethylene synthesis, Co(2+) and aminoethoxyvinylglycine (AVG), and two inhibitors of ethylene action, Ag(+) and CO2, are shown to delay the gravitropic response of cocklebur (Xanthium strumarium L.), tomato (Lycopersicon esculentum Mill.), and castor bean (Ricinus communis L.) stems. Gentle shaking on a mechanical shaker does not inhibit the gravitropic response, but vigorous hand shaking for 120 seconds delays the response somewhat. AVG and Ag(+) further delay the response of mechanically stimulated plants. AVG retards the storage of bending energy but not of stimulus. In gravitropism, graviperception may first stimulate ethylene evolution, which may then influence bending directly, or responses involving ethylene could be more indirect.

  3. The cell biology of lignification in higher plants

    PubMed Central

    Barros, Jaime; Serk, Henrik; Granlund, Irene; Pesquet, Edouard

    2015-01-01

    Background Lignin is a polyphenolic polymer that strengthens and waterproofs the cell wall of specialized plant cell types. Lignification is part of the normal differentiation programme and functioning of specific cell types, but can also be triggered as a response to various biotic and abiotic stresses in cells that would not otherwise be lignifying. Scope Cell wall lignification exhibits specific characteristics depending on the cell type being considered. These characteristics include the timing of lignification during cell differentiation, the palette of associated enzymes and substrates, the sub-cellular deposition sites, the monomeric composition and the cellular autonomy for lignin monomer production. This review provides an overview of the current understanding of lignin biosynthesis and polymerization at the cell biology level. Conclusions The lignification process ranges from full autonomy to complete co-operation depending on the cell type. The different roles of lignin for the function of each specific plant cell type are clearly illustrated by the multiple phenotypic defects exhibited by knock-out mutants in lignin synthesis, which may explain why no general mechanism for lignification has yet been defined. The range of phenotypic effects observed include altered xylem sap transport, loss of mechanical support, reduced seed protection and dispersion, and/or increased pest and disease susceptibility. PMID:25878140

  4. Gravitropism in higher plant shoots. V - Changing sensitivity to auxin

    NASA Technical Reports Server (NTRS)

    Salisbury, Frank B.; Gillespie, Linda; Rorabaugh, Patricia

    1988-01-01

    The relationship in plants between the sensitivity to auxin and differential growth and bending was investigated experimentally. Decapitated and marked sunflower hypocotyl sections were immersed in buffered auxin solutions of different concentrations (0, 10 to the -8th, or 0.001 molar) and were photographed at 1/2 hr intervals; the negatives were analyzed with a digitizer/computer to evaluate surface-length changes in terms of Michaelis-Menten enzyme kinetics. It was found that bending decreased with increasing concentration of auxin. Increasing the auxin concentration inhibits the elongation growth of lower surfaces but promotes upper-surface growth, indicating that the lower surfaces have a greater Km sensitivity to applied auxin than the upper surfaces. At optimum auxin levels (maximum growth), the growth of bottom surfaces exceeded that of top surfaces, indicating that bottom tissues had a greater Vmax sensitivity.

  5. Studies of genetic transformation of higher plants using irradiated pollen

    SciTech Connect

    Chyi, Y.S.

    1984-01-01

    Pandey has reported extensively on an unusual genetic phenomenon he called egg transformation. When compatible pollen was treated wth genetically lethal dosage of ..gamma..-radiation (100,000 rad), and used as mentor pollen to overcome selfincompatibility of several Nicotiana species, some genetic characters were found to be transferred from the radiation killed pollen to nonhybrid progeny. Observed transformants were fertile, cytogenetically normal, and had maternal phenotypes except for those specific traits transferred from the donors. Heavily irradiated pollen was believed to discharge its radiation-fragmented DNA (chromatin) into the embryo sac and bring about the transformation of the egg. The frequency of gene transfer was reported to be over 50%, and happened for all three characters Pandey studied - self incompatible specificities, flower color, and pollen color. Plant species studied were tomato, pea, apple, rapeseed, and Nicotiana species, including various stocks from Dr. Pandey. Treatments included pollinations with soley irradiated donor pollen, with a mixture of irradiated donor and normal self pollen, with a mixture of normal donor and self pollen, and double pollinations with irradiated donor pollen and normal self pollen, using different time intervals to separate the two pollinations. A total of 6210 pollinations were made, and 17,522 seedlings representing 87,750 potential transformational events were screened. In no case was an unambiguous transformant recovered. This research was unable to confirm or expand upon the findings of Dr. Pandey, or elucidate the mechanisms underlying such phenomena. Alternative explanations for Pandey's data were postulated. This approach to gene transfer by using irradiated pollen appears to be of little practical use to plant breeders.

  6. Radio Counterparts to SXR Transients

    NASA Astrophysics Data System (ADS)

    Gary, D. E.

    1999-12-01

    By now several studies have been done on small-scale brightenings seen at radio, UV, EUV, and soft X-ray wavelengths. These are to be reviewed by Kundu in these proceedings. In this talk we concentrate on the radio counterpart of a particular type of brightening---the soft X-ray transient brightenings of Shimizu. These brightenings are associated with active regions, and a study of radio counterparts by White et al. (1995) using Nobeyama data found an excellent correspondence between the 17 GHz and SXR brightenings, both spatially and temporally. However, this study found that both the SXR and microwave emissions could be satisfactorily explained as purely thermal emission, and a search of BATSE hard X-ray data showed no nonthermal counterpart. White et al. (1995) were forced to conclude that the events may be different from flares. A more sensitive search for nonthermal emission was needed, in particular using lower frequency microwaves where the influence of nonthermal electrons would be more easily detected. Gary, Hartl and Shimizu (1997) found 34 SXR transient brightenings over a 10-day period in May 1992, for which OVRO (1-18 GHz) total power data were available. A comparison of the data showed a number of clear nonthermal signatures. In addition, one of the events was seen in the lowest energy (6-9.3 keV) channel of the BATSE SPEC detector, suggesting a connection between the microflares discovered in hard X-rays by Lin et al. (1984). The evidence that SXR transient brightenings are microflares is reviewed in this talk. We also attempt to place other small-scale brightenings in context with regard to SXR transient brightenings and microflares.

  7. Higher Plants in Space for MELiSSA -Literature Review and Future Directions

    NASA Astrophysics Data System (ADS)

    Zabrodina, Marina; Kittang, Ann-Iren; Coelho, Liz Helena; Karoliussen, Irene; Aase Wolff, Silje; Iversen, Tor-Henning

    The human exploration of space requires the development of closed life support systems to regenerate oxygen, purify water, and produce food. MELiSSA (Micro-Ecological Life Support System Alternative) is a model system for advanced life support based on different microbial species and higher plants. The main objective of the LiRHiPliSMe (Literature Review of Higher Plants in Space for MELiSSA) project was to elaborate the preliminary roadmap for higher plant research activities for the MELiSSA project Phase 2 (Preliminary Space Experiments). The first task was to establish an understanding of the current knowledge concerning how higher plant will adapt to Moon/Mars physical factors different from Earth with focus on reduced gravity, space radiation, variations in magnetic field and combined effects of these factors. The literature related to how Moon/Mars physical factors can affect genetic processes, growth regulators, development, morphology, water and nutrients transport, gas exchange and metabolism of higher plants during one life cycle were collected. The possible effects of the space environment on the plant role as a food and on the mass balance in a Life Support System that includes a Higher Plant Compartment are reviewed. Based on this literature review there was made an assessment of where new or extended scientific knowledge about space factors effects on higher plant growth and development is needed. The requirements for research activities on higher plants in enclosed life support systems were identified. The required higher plant research activities for MELiSSA phase 2 both on ground and in space were placed in a timescale from the present until higher plants can be grown in closed life support systems on Moon and Mars.

  8. NUCLEAR DNA AND CYTOPLASMIC DNA FROM TISSUES OF HIGHER PLANTS

    PubMed Central

    Hotta, Yasuo; Bassel, Alix; Stern, Herbert

    1965-01-01

    Young wheat roots were labeled with 32P-inorganic phosphate. Following the labeling period, roots were homogenized in a sucrose medium and fractionated into nuclei, cytoplasmic particles (including proplastids and mitochondria), and a soluble fraction containing most of the microsomes. DNA prepared from the particles had a higher buoyant density than that from the nuclei and showed a marked loss in total label if the roots were exposed to non-radioactive medium for 48 hours prior to fractionation of the cells. PMID:5885425

  9. Phosphate transporters from the higher plant Arabidopsis thaliana.

    PubMed Central

    Muchhal, U S; Pardo, J M; Raghothama, K G

    1996-01-01

    Two cDNAs (AtPT1 and AtPT2) encoding plant phosphate transporters have been isolated from a library prepared with mRNA extracted from phosphate-starved Arabidopsis thaliana roots, The encoded polypeptides are 78% identical to each other and show high degree of amino acid sequence similarity with high-affinity phosphate transporters of Saccharomyces cerevisiae, Neurospora crassa, and the mycorrhizal fungus Glomus versiforme. The AtPT1 and AtPT2 polypeptides are integral membrane proteins predicted to contain 12 membrane-spanning domains separated into two groups of six by a large charged hydrophilic region. Upon expression, both AtPT1 and AtPT2 were able to complement the pho84 mutant phenotype of yeast strain NS219 lacking the high-affinity phosphate transport activity. AtPT1 and AtPT2 are representatives of two distinct, small gene families in A. thaliana. The transcripts of both genes are expressed in roots and are not detectable in leaves. The steady-state level of their mRNAs increases in response to phosphate starvation. Images Fig. 3 Fig. 4 Fig. 5 PMID:8927627

  10. Molecular insights into Zeaxanthin-dependent quenching in higher plants

    PubMed Central

    Xu, Pengqi; Tian, Lijin; Kloz, Miroslav; Croce, Roberta

    2015-01-01

    Photosynthetic organisms protect themselves from high-light stress by dissipating excess absorbed energy as heat in a process called non-photochemical quenching (NPQ). Zeaxanthin is essential for the full development of NPQ, but its role remains debated. The main discussion revolves around two points: where does zeaxanthin bind and does it quench? To answer these questions we have followed the zeaxanthin-dependent quenching from leaves to individual complexes, including supercomplexes. We show that small amounts of zeaxanthin are associated with the complexes, but in contrast to what is generally believed, zeaxanthin binding per se does not cause conformational changes in the complexes and does not induce quenching, not even at low pH. We show that in NPQ conditions zeaxanthin does not exchange for violaxanthin in the internal binding sites of the antennas but is located at the periphery of the complexes. These results together with the observation that the zeaxanthin-dependent quenching is active in isolated membranes, but not in functional supercomplexes, suggests that zeaxanthin is acting in between the complexes, helping to create/participating in a variety of quenching sites. This can explain why none of the antennas appears to be essential for NPQ and the multiple quenching mechanisms that have been observed in plants. PMID:26323786

  11. Automorphosis of higher plants on a 3-D clinostat

    NASA Astrophysics Data System (ADS)

    Hoson, T.; Kamisaka, S.; Yamashita, M.; Masuda, Y.

    On a three-dimensional (3-D) clinostat, various plant organs developed statocytes capable of responding to the gravity vector. The graviresponse of primary roots of garden cress and maize grown on the clinostat was the same as the control roots, whereas that of maize coleoptiles was reduced. When maize seedlings were grown in the presence of 10^-4 M gibberellic acid and kinetin, the graviresponse of both roots and shoots was suppressed. The corresponding suppression of amyloplast development was observed in the clinostatted and the hormone-treated seedlings. Maize roots and shoots showed spontaneous curvatures in different portions on the 3-D clinostat. The hormone treatment did not significantly influence such an automorphic curvature. When the root cap was removed, maize roots did not curve gravitropically. However, the removal suppressed the automorphic curvatures only slightly. On the other hand, the removal of coleoptile tip did not influence its graviresponse, whereas the spontaneous curvature of decapitated coleoptiles on the clinostat was strongly suppressed. Also, cytochalasin B differently affected the gravitropic and the automorphic curvatures of maize roots and shoots. From these results it is concluded that the graviperception and the early processes of signal transmission are unnecessary for automorphoses under simulated microgravity conditions. Moreover, the results support the view that the amyloplasts act as statoliths probably via an interaction with microfilaments.

  12. Molecular biology of Lea genes of higher plants

    SciTech Connect

    Not Available

    1991-07-01

    This report contains our progress to date in determining the function of the D-7 Lea proteins in cotton embryos. We have completely sequenced the D-7 gene and established {ital E. coli} transformants which synthesize reasonable amounts of the D-7 protein. Two-dimensional electrophoresis was required to assay fractions for D-7 protein during purification to homogeneity, since D-7 has no known enzymatic activity, contains no Trp, and little Phe or Tyr, and {ital E. coli} has several proteins of similar molecular weight to D-7. Purified D-7 was used to generate monospecific antibodies which are being used for determination of the cellular distribution of D-7, and also for exact quantitation of D-7 in late-stage cotton embryos. Computerized modelling of D-7 has shown similarities to proteins with a coiled-coil structure, but fitting D-7 to this structure resulted in a violation of the handedness rule. If the pitch of the helix is changed from 3.6 to 3.667, however, a three dimensional structure (not a coiled coil) is generated which has overall energetics of formation nearly as favorable as the traditional {alpha} helix. The driving force for the change in pitch is proposed to result from favorable energetics of dimerization. Preliminary evidence indicates that D-7 does indeed dimerize in solution. Future experiments will determine the exact 3D structure of D-7 and the related protein D-29, as well as test the hypothesis that D-7 and D-29 are involved in mitigating dehydration of embryos and plants through sequestering phosphate or other ions in sufficient quantity to prevent ion precipitation or crystallization. 13 refs., 3 figs. (MHB)

  13. Effects of the Extraterrestrial Environment on Plants: Recommendations for Future Space Experiments for the MELiSSA Higher Plant Compartment

    PubMed Central

    Wolff, Silje A.; Coelho, Liz H.; Karoliussen, Irene; Jost, Ann-Iren Kittang

    2014-01-01

    Due to logistical challenges, long-term human space exploration missions require a life support system capable of regenerating all the essentials for survival. Higher plants can be utilized to provide a continuous supply of fresh food, atmosphere revitalization, and clean water for humans. Plants can adapt to extreme environments on Earth, and model plants have been shown to grow and develop through a full life cycle in microgravity. However, more knowledge about the long term effects of the extraterrestrial environment on plant growth and development is necessary. The European Space Agency (ESA) has developed the Micro-Ecological Life Support System Alternative (MELiSSA) program to develop a closed regenerative life support system, based on micro-organisms and higher plant processes, with continuous recycling of resources. In this context, a literature review to analyze the impact of the space environments on higher plants, with focus on gravity levels, magnetic fields and radiation, has been performed. This communication presents a roadmap giving directions for future scientific activities within space plant cultivation. The roadmap aims to identify the research activities required before higher plants can be included in regenerative life support systems in space. PMID:25370192

  14. Effects of the Extraterrestrial Environment on Plants: Recommendations for Future Space Experiments for the MELiSSA Higher Plant Compartment.

    PubMed

    Wolff, Silje A; Coelho, Liz H; Karoliussen, Irene; Jost, Ann-Iren Kittang

    2014-01-01

    Due to logistical challenges, long-term human space exploration missions require a life support system capable of regenerating all the essentials for survival. Higher plants can be utilized to provide a continuous supply of fresh food, atmosphere revitalization, and clean water for humans. Plants can adapt to extreme environments on Earth, and model plants have been shown to grow and develop through a full life cycle in microgravity. However, more knowledge about the long term effects of the extraterrestrial environment on plant growth and development is necessary. The European Space Agency (ESA) has developed the Micro-Ecological Life Support System Alternative (MELiSSA) program to develop a closed regenerative life support system, based on micro-organisms and higher plant processes, with continuous recycling of resources. In this context, a literature review to analyze the impact of the space environments on higher plants, with focus on gravity levels, magnetic fields and radiation, has been performed. This communication presents a roadmap giving directions for future scientific activities within space plant cultivation. The roadmap aims to identify the research activities required before higher plants can be included in regenerative life support systems in space. PMID:25370192

  15. Optical counterpart of ICRF: HIPPARCOS

    NASA Astrophysics Data System (ADS)

    Lindegren, L.; Perryman, M. A. C.

    The Hipparcos reference frame is defined by the positions and proper motions of nearly 118,000 stars given in the Hipparcos Catalogue. It is the optical counterpart of the International Celestial Reference Frame defined by the radio positions of extragalactic sources. The presentation gives a summary of the intrinsic properties of the Hipparcos reference frame, while its relation to the ICRF is discussed separately by J.~Kovalevsky. Median standard errors for stars brighter than 9~mag are around 0.8~mas in position at the catalogue epoch (J1991.25) and 0.9~ mas/yr in proper motion. The quality of the optical reference frame depends also on less easily quantified characteristics of the catalogue data, such as the uniformity and consistency of the astrometric data, the existence of temporal and spatial correlations, and the effects of unresolved binaries. The format of the Hipparcos Catalogue and its availability on different media are summarised.

  16. Expanding the docosahexaenoic acid food web for sustainable production: engineering lower plant pathways into higher plants

    PubMed Central

    Petrie, James R.; Singh, Surinder P.

    2011-01-01

    Background Algae are becoming an increasingly important component of land plant metabolic engineering projects. Land plants and algae have similar enough genetics to allow relatively straightforward gene transfer and they also share enough metabolic similarities that algal enzymes often function in a plant cell environment. Understanding metabolic systems in algae can provide insights into homologous systems in land plants. As examples, algal models are currently being used by several groups to better understand starch and lipid metabolism and catabolism, fields which have relevance in land plants. Importantly, land plants and algae also have enough metabolic divergence that algal genes can often provide new metabolic traits to plants. Furthermore, many algal genomes have now been sequenced, with many more in progress, and this easy access to genome-wide information has revealed that algal genomes are often relatively simple when compared with plants. Scope One example of the importance of algal, and in particular microalgal, resources to land plant research is the metabolic engineering of long-chain polyunsaturated fatty acids into oilseed crops which typically uses microalgal genes to extend existing natural plant biosynthetic pathways. This review describes both recent progress and remaining challenges in this field. PMID:22476481

  17. Phosphoinositide kinases and the synthesis of polyphosphoinositides in higher plant cells

    NASA Technical Reports Server (NTRS)

    Drobak, B. K.; Dewey, R. E.; Boss, W. F.; Davies, E. (Principal Investigator)

    1999-01-01

    Phosphoinositides are a family of inositol-containing phospholipids which are present in all eukaryotic cells. Although in most cells these lipids, with the exception of phosphatidylinositol, constitute only a very minor proportion of total cellular lipids, they have received immense attention by researchers in the past 15-20 years. This is due to the discovery that these lipids, rather than just having structural functions, play key roles in a wide range of important cellular processes. Much less is known about the plant phosphoinositides than about their mammalian counterparts. However, it has been established that a functional phosphoinositide system exists in plant cells and it is becoming increasingly clear that inositol-containing lipids are likely to play many important roles throughout the life of a plant. It is not our intention to give an exhaustive overview of all aspects of the field, but rather we focus on the phosphoinositide kinases responsible for the synthesis of all phosphorylated forms of phosphatidylinositol. Also, we mention some of the aspects of current phosphoinositide research which, in our opinion, are most likely to provide a suitable starting point for further research into the role of phosphoinositides in plants.

  18. The effect of higher plant microflora on the microbial landscape of a closed ecosystem

    NASA Astrophysics Data System (ADS)

    Tirranen, Lyalya; Gitelson, Josef; Borodina, Elena

    2012-07-01

    Having summarized certain data obtained earlier, we defined the aim of this work as an estimation of the effect of higher plant microflora on the microbial landscape of a closed ecosystem (CES). The microflora of such a component as higher plants can influence other system components not only by way of transfer with air and water flows, but also through the direct contact of the crew with the crops cultivated within CES when harvesting, thrashing, using them for food. Involving the higher plant component into the closed system the microorganism diversity and occurrence of microscopic fungi in other components of the closed ecosystem increased. The presence of microscopic fungi, especially on plants and in the air, is potentially dangerous for the health of the system residents. Since the contribution of the higher plant microflora (especially mycoflora) to the microbial landscape of a CES is significant, it is necessary to reduce the microbial flora of the higher plant component and limit its dispersion to other system components. One of the possible measures to limit the higher plant microflora colonization is air purification between components. Reducing the number of microscopic fungi by decreasing the humidity in the system's atmosphere should also be considered.

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

    NASA Astrophysics Data System (ADS)

    Cormier, Marc-André; Kahmen, Ansgar

    2015-04-01

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

  20. Monovinyl and Divinyl Protochlorophyllide Pools in Etiolated Tissues of Higher Plants 1

    PubMed Central

    Shioi, Yuzo; Takamiya, Ken-ichiro

    1992-01-01

    The composition of chlorophyll-precursor pigments, particularly the contents of monovinyl (MV) and divinyl (DV) protochlorophyllides (Pchlides), in etiolated tissues of higher plants were determined by polyethylene-column HPLC (Y. Shioi, S. I. Beale [1987] Anal Biochem 162: 493-499), which enables the complete separation of these pigments. DV-Pchlide was ubiquitous in etiolated tissue of higher plants. From the analyses of 24 plant species belonging to 17 different families, it was shown that the concentration of DV-Pchlide was strongly dependent on the plant species and the age of the plants. The ratio of DV-Pchlide to MV-Pchlide in high DV-Pchlide plants such as cucumber and leaf mustard decreased sharply with increasing age. Levels of DV-Pchlide in Gramineae plants were considerably lower at all ages compared with those of other plants. Etiolated tissues of higher plants such as barley and corn were, therefore, good sources of MV-Pchlide. Absorption spectra of the purified MV- and DV-Pchlides in ether are presented and compared. PMID:16653119

  1. Significantly higher activity of a cytoplasmic hammerhead ribozyme than a corresponding nuclear counterpart: engineered tRNAs with an extended 3′ end can be exported efficiently and specifically to the cytoplasm in mammalian cells

    PubMed Central

    Kuwabara, Tomoko; Warashina, Masaki; Koseki, Shiori; Sano, Masayuki; Ohkawa, Jun; Nakayama, Kazuhisa; Taira, Kazunari

    2001-01-01

    Hammerhead ribozymes were expressed under the control of similar tRNA promoters, localizing transcripts either in the cytoplasm or the nucleus. The tRNAVal-driven ribozyme (tRNA-Rz; tRNA with extra sequences at the 3′ end) that has been used in our ribozyme studies was exported efficiently into the cytoplasm and ribozyme activity was detected only in the cytoplasmic fraction. Both ends of the transported tRNA-Rz were characterized comprehensively and the results confirmed that tRNA-Rz had unprocessed 5′ and 3′ ends. Furthermore, it was also demonstrated that the activity of the exported ribozyme was significantly higher than that of the ribozyme which remained in the nucleus. We suggest that it is possible to engineer tRNA-Rz, which can be exported to the cytoplasm based on an understanding of secondary structures, and then tRNA-driven ribozymes may be co-localized with their target mRNAs in the cytoplasm of mammalian cells. PMID:11433023

  2. The ways of controlling microbiota of the higher plant link in LSS

    NASA Astrophysics Data System (ADS)

    Tirranen, L. S.; Gitelson, I. I.

    The ways of controlling microbiota of the higher plant link have been considered, as the sterile plant growth in closed ecological human life support systems is impossible. One of the ways of controlling the link microbial community - building sterile intrasystem barriers between the system links - is problematic and dangerous. An accidental breach of microorganisms through the barrier can lead to disastrous consequences - either unrestrained reproduction of microbes including pathogenic and conditionally pathogenic species or, on the contrary, elimination of species most valuable for the given microbial community. Another way of control is maintaining suitable conditions for human and plant habitat, creating some constructive system properties directed at microbial exchange weakening. The use of catalytic furnace for oxidizing organic impurities in system atmosphere, UV processing of air and plants in the phytotron before and in the beginning of the experiments promoted decrease of microorganism amount in the link. To restrict the distribution of microorganisms of the higher plant link in other system links the module for yield processing being under constant suction was isolated. To prevent the introduction of microorganisms into the system we applied the UV processing of all objects transferred to the system and continuous atmosphere overpressure inside the system. It is important to detect the ultimate amount of microorganism indicator groups in the higher plant link biocenosis. It would indicate the microbial pollution of the link and be the signal for regulation of its microbial population or processing technologies in the studied objects. There were two 4-month experiments with the "human - higher plants" closed ecosystem carried out. There was no progressive deterioration for plants, decrease of wheat yield to zero and rapid growth of microorganisms in the higher plant link after making all listed arrangements. Microbiological analyses of the studied

  3. 50 CFR 402.04 - Counterpart regulations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... ADMINISTRATION, DEPARTMENT OF COMMERCE); ENDANGERED SPECIES COMMITTEE REGULATIONS SUBCHAPTER A INTERAGENCY COOPERATION-ENDANGERED SPECIES ACT OF 1973, AS AMENDED General § 402.04 Counterpart regulations....

  4. 50 CFR 402.04 - Counterpart regulations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... ADMINISTRATION, DEPARTMENT OF COMMERCE); ENDANGERED SPECIES COMMITTEE REGULATIONS SUBCHAPTER A INTERAGENCY COOPERATION-ENDANGERED SPECIES ACT OF 1973, AS AMENDED General § 402.04 Counterpart regulations....

  5. 50 CFR 402.04 - Counterpart regulations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... ADMINISTRATION, DEPARTMENT OF COMMERCE); ENDANGERED SPECIES COMMITTEE REGULATIONS SUBCHAPTER A INTERAGENCY COOPERATION-ENDANGERED SPECIES ACT OF 1973, AS AMENDED General § 402.04 Counterpart regulations....

  6. 50 CFR 402.04 - Counterpart regulations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... ADMINISTRATION, DEPARTMENT OF COMMERCE); ENDANGERED SPECIES COMMITTEE REGULATIONS SUBCHAPTER A INTERAGENCY COOPERATION-ENDANGERED SPECIES ACT OF 1973, AS AMENDED General § 402.04 Counterpart regulations....

  7. Two Categories of 13C/12C Ratios for Higher Plants 1

    PubMed Central

    Smith, Bruce N.; Epstein, Samuel

    1971-01-01

    13C/12C ratios have been determined for plant tissue from 104 species representing 60 families. Higher plants fall into two categories, those with low δPDBI13C values (—24 to —34‰) and those with high δ 13C values (—6 to —19‰). Algae have δ 13C values of —12 to —23‰. Photosynthetic fractionation leading to such values is discussed. PMID:16657626

  8. PII in higher plants: a modern role for an ancient protein.

    PubMed

    Uhrig, R Glen; Ng, Kenneth K S; Moorhead, Greg B G

    2009-09-01

    PII in prokaryotic organisms is a crucial integrator of cellular carbon, nitrogen and energy levels. In higher plants, however, its role remains significantly less clear. Previous findings suggest that PII-N-acetylglutamate kinase (NAGK) complex formation controls l-arginine biosynthesis, whereas other work implicates PII in regulating chloroplastic NO2(-) uptake. Together, these findings indicate that PII has evolved from a central metabolic role in prokaryotes towards a more specialized role in eukaryotes. Furthermore, recent genomic and bioinformatic findings reveal tissue-specific expression of PII in higher plants, with transcriptional expression patterns suggestive of a link between PII and storage protein production during seed development. This review focuses on the unique structural, biochemical and biological aspects of PII in higher plants. PMID:19720555

  9. Adaptations to increasing hydraulic stress: morphology, hydrodynamics and fitness of two higher aquatic plant species.

    PubMed

    Puijalon, Sara; Bornette, Gudrun; Sagnes, Pierre

    2005-02-01

    Sessile organisms often exhibit morphological changes in response to permanent exposure to mechanical stimulation (wind or water movements). The adaptive value of these morphological changes (hydrodynamic performance and consequences on fitness) has not been studied extensively, particularly for higher plants submitted to flow stress. The aim was to determine the adaptive value of morphological patterns observed within two higher aquatic plant species, Berula erecta and Mentha aquatica, growing along a natural flow stress gradient. The hydrodynamic ability of each ramet was investigated through quantitative variables (drag coefficient and E-value). Fitness-related traits based on vegetative growth and clonal multiplication were assessed for each individual. For both species, the drag coefficient and the E-value were explained only to a limited extent by the morphological traits used. B. erecta exhibited a reduction in size and low overall plant drag at higher flow velocities, despite high drag values relative to leaf area, due to a low flexibility. The plants maintained their fitness, at least in part, through biomass reallocation: one tall ramet at low velocity, but shorter individuals with many interconnected stolons when flow velocity increased. For M. aquatica, morphological differences along the velocity gradient did not lead to greater hydrodynamic performance. Plant size increased with increasing velocities, suggesting the indirect effects of current favouring growth in high velocities. The fitness-related traits did not demonstrate lower plant fitness for high velocities. Different developmental constraints linked to plant morphology and trade-offs between major plant functions probably lead to different plant responses to flow stress. PMID:15642713

  10. Growth and development in inert non-aqueous liquids. [of higher plants

    NASA Technical Reports Server (NTRS)

    Siegel, S. M.

    1974-01-01

    A preview is presented of the survival and growth capabilities of higher plants in non-aqueous, inert liquids. The two media which were used are mineral (white) oil and fluorochemical inert liquid FC-75. Both liquids dissolve oxygen and carbon dioxide readily, but are insoluble in water. Consequently, plants submerged in these liquids are capable of gas exchange with the atmosphere, but possess a water impermeable coating the dimensions of which are determined by the size of the liquid holding container. In a sense, growing plants in a tank of mineral oil imparts on them a cuticle. Plants plus prescribed volumes of water were innoculated into mineral oil. Organisms with minimal water supplied could then be observed. Also, submersed plants covered with an oil slick were shown to be capable of growth in dessicating atmospheres.

  11. Aquatic food production modules in bioregenerative life support systems based on higher plants

    NASA Astrophysics Data System (ADS)

    Bluem, V.; Paris, F.

    Most bioregenerative life support systems (BLSS) are based on gravitropic higher plants which exhibit growth and seed generation disturbances in microgravity. Even when used for a lunar or martian base the reduced gravity may induce a decreased productivity in comparison to Earth. Therefore, the implementation of aquatic biomass production modules in higher plant and/or hybrid BLSS may compensate for this and offer, in addition, the possibility to produce animal protein for human nutrition. It was shown on the SLS-89 and SLS-90 space shuttle missions with the C.E.B.A.S.-MINI MODULE that the edible non gravitropic rootless higher aquatic plant Ceratophyllum demeresum exhibits an undisturbed high biomass production rate in space and that the teleost fish species, Xiphophorus helleri, adapts rapidly to space conditions without loss of its normal reproductive functions. Based on these findings a series of ground-based aquatic food production systems were developed which are disposed for utilization in space. These are plant production bioreactors for the species mentioned above and another suitable candidate, the lemnacean (duckweed) species, Wolffia arrhiza. Moreover, combined intensive aquaculture systems with a closed food loop between herbivorous fishes and aquatic and land plants are being developed which may be suitable for integration into a BLSS of higher complexity.

  12. Leaf Optical Properties in Higher Plants: Linking Spectral Characteristics with Plant Stress

    NASA Technical Reports Server (NTRS)

    Carter, Gregory A.; Knapp, Alan K.

    1999-01-01

    A number of studies have addressed responses of leaf spectral reflectance, transmittance, or absorptance to physiological stress. Stressors included dehydration, ozone, herbicides, disease, insufficient mycorrhizae and N fertilization, flooding and insects. Species included conifers, grasses, and broadleaved trees. Increased reflectance with maximum responses near 700 nm wavelength occurred in all cases. Varying the chlorophyll content in leaves or pigment extracts can simulate this effect. Thus, common optical responses to stress result from decreases in leaf chlorophyll contents or the capacity of chloroplasts to absorb light. Leaf optic can be quite sensitive to any stressor that alters soil-plant-atmosphere processes.

  13. Community College Global Counterparts: Historical Contexts

    ERIC Educational Resources Information Center

    Latiner Raby, Rosalind; Valeau, Edward J.

    2013-01-01

    Since 1971, scholarship on community college global counterparts has documented the nuances of these institutions and charted their similarities to one another. The purpose of this article is to detail the first three decades of community college global-counterpart scholarship from 1971-2001. Within each decade there exists scholarship that…

  14. Demonstration of ATP-dependent, ubiquitin-conjugating activities in higher plants

    SciTech Connect

    Vierstra, R.D.

    1986-05-01

    Ubiquitin is a 76 amino acid eucaryotic polypeptide with several important functions that arise from its ability to become covalently ligated to other cytoplasmic and nuclear proteins. Ubiquitin has recently been purified from higher plants and found to be very homologous, both structurally and functionally, to the highly conserved animal form. Here, the authors present evidence that crude extracts from several plants have the capacity to conjugate ubiquitin to other plant proteins using either labelled human or oat ubiquitin as a substrate. The reaction requires ATP and can be detected in soluble extracts from dry seeds, etiolated shoots and green leaves, with etiolated shoot extracts having the highest activity. Mixing experiments indicate that the low activity found with green tissue in vitro is the result of an endogenous inhibitor. The conjugating activities are extremely labile with a half-life of 20 min at 30/sup 0/C. The addition of polyphenol inhibitors fails to protect the system from this inactivation. In addition to conjugating activities, crude plant extracts also have ATP-independent activities that degrade ubiquitin conjugates. These results provide the first evidence that higher plants contain the necessary enzymes for ubiquitin conjugate formation. Further analysis of these activities should help clarify the functions of ubiquitination in plants.

  15. Design and optimization of an experimental bioregenerative life support system with higher plants and silkworms

    NASA Astrophysics Data System (ADS)

    Hu, Enzhu; Bartsev, Sergey I.; Zhao, Ming; Liu, Professor Hong

    The conceptual scheme of an experimental bioregenerative life support system (BLSS) for planetary exploration was designed, which consisted of four elements - human metabolism, higher plants, silkworms and waste treatment. 15 kinds of higher plants, such as wheat, rice, soybean, lettuce, mulberry, et al., were selected as regenerative component of BLSS providing the crew with air, water, and vegetable food. Silkworms, which producing animal nutrition for crews, were fed by mulberry-leaves during the first three instars, and lettuce leaves last two instars. The inedible biomass of higher plants, human wastes and silkworm feces were composted into soil like substrate, which can be reused by higher plants cultivation. Salt, sugar and some household material such as soap, shampoo would be provided from outside. To support the steady state of BLSS the same amount and elementary composition of dehydrated wastes were removed periodically. The balance of matter flows between BLSS components was described by the system of algebraic equations. The mass flows between the components were optimized by EXCEL spreadsheets and using Solver. The numerical method used in this study was Newton's method.

  16. Compilation and classification of higher plant mitochondrial tRNA genes.

    PubMed Central

    Veronico, P; Gallerani, R; Ceci, L R

    1996-01-01

    This compilation reports the tRNA genes detected on higher plant mitochondrial genomes subdivided into the widely accepted categories of 'genuine' and 'chloroplast-like' genes. Moreover, it includes a list of pseudo or truncated genes divided in the same way. PMID:8710486

  17. Compilation and classification of higher plant mitochondrial tRNA genes.

    PubMed

    Veronico, P; Gallerani, R; Ceci, L R

    1996-06-15

    This compilation reports the tRNA genes detected on higher plant mitochondrial genomes subdivided into the widely accepted categories of 'genuine' and 'chloroplast-like' genes. Moreover, it includes a list of pseudo or truncated genes divided in the same way. PMID:8710486

  18. Comparative Studies on Plastoquinones. III. Distribution of Plastoquinones in Higher Plants 1

    PubMed Central

    Barr, Rita; Crane, F. L.

    1967-01-01

    The distribution of plastoquinones A 45, B and C was studied in representatives from 34 different plant families beginning with liverworts and mosses to higher plants. All of these species, including many monocots and dicots, contained significant amounts of the 3 quinones. Two species of Aesculus contained plastoquinone A 20 in addition to plastoquinone A 45, B, and C. Many dicots, such as Aesculus, watermelon, tobacco and tomato accumulated increasing quantities of plastoquinones A and C1-C4 during the growing season. The concentrations of plastoquinones B and C5-C6 tended to remain at a constant low level during the season (<0.01 μmole per mg chlorophyll). Preliminary studies with bean plants (Vicia faba and Phaseolus sp.) indicate that the levels of quinones varied little under different growth conditions (day length and temp.) although Vicia faba tended to have higher PQ A values with increased temperature. PMID:16656647

  19. Soybean ribulose bisphosphate carboxylase small subunit: Mechanisms and determinants of RNA turnover in higher plants

    SciTech Connect

    Meagher, R.B.

    1990-02-01

    The goals of examining the mechanisms and determinants of RNA turnover in higher plants remain the same. We will continue with two of the major approaches (1) in vivo chemical modification of RNA structure and (2) analysis of Rubisco SSU RNA structure and turnover in transgenic plants. We plan to reduce the amount of molecular physiology (studies of transcription and steady state levels) to a minimum and expand these efforts into the analysis of plant rebonucleases. We have also broadened our examination of light induced turnover of rubisco SSU RNA to include general RNA turnover. We plan to identify specific 3{prime}->5{prime} precessive ribonuclease by complementation of E. coli mutants. The activity of these novel RNases and their potential role in plant RNA turnover and processing will be characterized.

  20. Diurnal adjustment in ultraviolet sunscreen protection is widespread among higher plants.

    PubMed

    Barnes, Paul W; Flint, Stephan D; Tobler, Mark A; Ryel, Ronald J

    2016-05-01

    The accumulation of ultraviolet (UV)-absorbing compounds (flavonoids and related phenylpropanoids) in the epidermis of higher plants reduces the penetration of solar UV radiation to underlying tissues and is a primary mechanism of acclimation to changing UV conditions resulting from ozone depletion and climate change. Previously we reported that several herbaceous plant species were capable of rapid, diurnal adjustments in epidermal UV transmittance (T UV), but how widespread this phenomenon is among plants has been unknown. In the present study, we tested the generality of this response by screening 37 species of various cultivated and wild plants growing in four locations spanning a gradient of ambient solar UV and climate (Hawaii, Utah, Idaho and Louisiana). Non-destructive measurements of adaxial T UV indicated that statistically significant midday decreases in T UV occurred in 49 % of the species tested, including both herbaceous and woody growth forms, and there was substantial interspecific variation in the magnitude of these changes. In general, plants in Louisiana exhibited larger diurnal changes in T UV than those in the other locations. Moreover, across all taxa, the magnitude of these changes was positively correlated with minimum daily air temperatures but not daily UV irradiances. Results indicate that diurnal changes in UV shielding are widespread among higher plants, vary both within and among species and tend to be greatest in herbaceous plants growing in warm environments. These findings suggest that plant species differ in their UV protection "strategies" though the functional and ecological significance of this variation in UV sunscreen protection remains unclear at present. PMID:26809621

  1. Gene expression and regulation of higher plants under soil water stress.

    PubMed

    Ni, Fu-Tai; Chu, Li-Ye; Shao, Hong-Bo; Liu, Zeng-Hui

    2009-06-01

    Higher plants not only provide human beings renewable food, building materials and energy, but also play the most important role in keeping a stable environment on earth. Plants differ from animals in many aspects, but the important is that plants are more easily influenced by environment than animals. Plants have a series of fine mechanisms for responding to environmental changes, which has been established during their long-period evolution and artificial domestication. The machinery related to molecular biology is the most important basis. The elucidation of it will extremely and purposefully promote the sustainable utilization of plant resources and make the best use of its current potential under different scales. This molecular mechanism at least includes drought signal recognition (input), signal transduction (many cascade biochemical reactions are involved in this process), signal output, signal responses and phenotype realization, which is a multi-dimension network system and contains many levels of gene expression and regulation. We will focus on the physiological and molecular adaptive machinery of plants under soil water stress and draw a possible blueprint for it. Meanwhile, the issues and perspectives are also discussed. We conclude that biological measures is the basic solution to solving various types of issues in relation to sustainable development and the plant measures is the eventual way. PMID:19949548

  2. Ty1-copia group retrotransposons are ubiquitous and heterogeneous in higher plants.

    PubMed Central

    Flavell, A J; Dunbar, E; Anderson, R; Pearce, S R; Hartley, R; Kumar, A

    1992-01-01

    We have used the polymerase chain reaction to isolate fragments of Ty1-copia group retrotransposons from a wide variety of members of the higher plant kingdom. 56 out of 57 species tested generate an amplified fragment of the size expected for reverse transcriptase fragments of Ty1-copia group retrotransposons. Sequence analysis of subclones shows that the PCR fragments display varying degrees of sequence heterogeneity. Sequence heterogeneity therefore seems a general property of Ty1-copia group retrotransposons of higher plants, in contrast to the limited diversity seen in retrotransposons of Saccharomyces cerevisiae and Drosophila melanogaster. Phylogenetic analysis of all these sequences shows, with some significant exceptions, that the degree of sequence divergence in the retrotransposon populations between any pair of species is proportional to the evolutionary distance between those species. This implies that sequence divergence during vertical transmission of Ty1-copia group retrotransposons within plant lineages has been a major factor in the evolution of Ty1-copia group retrotransposons in higher plants. Additionally, we suggest that horizontal transmission of this transposon group between different species has also played a role in this process. PMID:1379359

  3. Regulation of chloroplast number and DNA synthesis in higher plants. Final report, August 1995--August 1996

    SciTech Connect

    Mullet, J.E.

    1997-06-17

    The long term objective of this research is to understand the process of chloroplast development and its coordination with leaf development in higher plants. This is important because the photosynthetic capacity of plants is directly related to leaf and chloroplast development. This research focused on obtaining a detailed description of leaf development and the early steps in chloroplast development including activation of plastid DNA synthesis, changes in plastid DNA copy number, activation of chloroplast transcription and increases in plastid number per cell. The research focused on the isolation of the plastid DNA polymerase, and identification of genetic mutants which are altered in their accumulation of plastid DNA and plastid number per cell.

  4. Transcriptomes of Plant Gametophytes Have a Higher Proportion of Rapidly Evolving and Young Genes than Sporophytes

    PubMed Central

    Gossmann, Toni I.; Saleh, Dounia; Schmid, Marc W.; Spence, Michael A.; Schmid, Karl J.

    2016-01-01

    Reproductive traits in plants tend to evolve rapidly due to various causes that include plant-pollinator coevolution and pollen competition, but the genomic basis of reproductive trait evolution is still largely unknown. To characterize evolutionary patterns of genome wide gene expression in reproductive tissues in the gametophyte and to compare them to developmental stages of the sporophyte, we analyzed evolutionary conservation and genetic diversity of protein-coding genes using microarray-based transcriptome data from three plant species, Arabidopsis thaliana, rice (Oryza sativa), and soybean (Glycine max). In all three species a significant shift in gene expression occurs during gametogenesis in which genes of younger evolutionary age and higher genetic diversity contribute significantly more to the transcriptome than in other stages. We refer to this phenomenon as “evolutionary bulge” during plant reproductive development because it differentiates the gametophyte from the sporophyte. We show that multiple, not mutually exclusive, causes may explain the bulge pattern, most prominently reduced tissue complexity of the gametophyte, a varying extent of selection on reproductive traits during gametogenesis as well as differences between male and female tissues. This highlights the importance of plant reproduction for understanding evolutionary forces determining the relationship of genomic and phenotypic variation in plants. PMID:26956888

  5. Concentration and distribution of cobalt in higher plants: The use of micro-PIXE spectroscopy

    NASA Astrophysics Data System (ADS)

    Bakkaus, E.; Gouget, B.; Gallien, J.-P.; Khodja, H.; Carrot, F.; Morel, J. L.; Collins, R.

    2005-04-01

    Cobalt is not classified as an essential element for plants, however, it is usually described as "beneficial". This trace element can be a contaminant in soils due to agricultural additives or metal refineries. Certain plants species have the ability to extract metals (such as Co) from soils, thus, cleaning the environment. Therefore, knowledge of the physiological mechanisms of metal absorption is required to improve these phytoremediation technologies. Patterns of cobalt accumulation and storage were determined in tomato (Lycopersicon esculentum) and wheat (Triticum aestivum) species. Plants were grown in nutrient solutions, with different Co treatments, using controlled environmental conditions. The spatial distributions of K, Ca, Fe and Co in whole plants, and in leaf and stem sections, were examined by micro-PIXE. In conjunction, total Co concentrations were determined by ICP-MS. Micro-PIXE spectroscopy proved to be a convenient technique for indicating Co concentrations and distribution patterns in these plants. This knowledge aids in the identification of vegetal Co sequestration and, thus, helps to unravel how Co is transported in higher plants.

  6. Transcriptomes of Plant Gametophytes Have a Higher Proportion of Rapidly Evolving and Young Genes than Sporophytes.

    PubMed

    Gossmann, Toni I; Saleh, Dounia; Schmid, Marc W; Spence, Michael A; Schmid, Karl J

    2016-07-01

    Reproductive traits in plants tend to evolve rapidly due to various causes that include plant-pollinator coevolution and pollen competition, but the genomic basis of reproductive trait evolution is still largely unknown. To characterize evolutionary patterns of genome wide gene expression in reproductive tissues in the gametophyte and to compare them to developmental stages of the sporophyte, we analyzed evolutionary conservation and genetic diversity of protein-coding genes using microarray-based transcriptome data from three plant species, Arabidopsis thaliana, rice (Oryza sativa), and soybean (Glycine max). In all three species a significant shift in gene expression occurs during gametogenesis in which genes of younger evolutionary age and higher genetic diversity contribute significantly more to the transcriptome than in other stages. We refer to this phenomenon as "evolutionary bulge" during plant reproductive development because it differentiates the gametophyte from the sporophyte. We show that multiple, not mutually exclusive, causes may explain the bulge pattern, most prominently reduced tissue complexity of the gametophyte, a varying extent of selection on reproductive traits during gametogenesis as well as differences between male and female tissues. This highlights the importance of plant reproduction for understanding evolutionary forces determining the relationship of genomic and phenotypic variation in plants. PMID:26956888

  7. Utility of specific locus systems in higher plants to monitor for mutagens.

    PubMed Central

    Constantin, M J

    1978-01-01

    Plants possess biological and operational attributes that have encouraged geneticists to use them extensively in the development of fundamental genetic concepts. Attributes such as regenerative plasticity, high fecundity, cultural adaptability, range of ploidy, economics of culture and maintenance of specific populations, and versatility make plant genetic systems prime candidates with which to monitor the environment for mutagens. A specific locus (equivalent to a classical Mendelian gene) controls the development of a phenotypic characteristic. It can also mutate to a new allelic form with a consequentially altered phenotypic characteristic and can be separated by crossing over from adjacent loci that govern other specific phenotypic characteristics. Since various plant species have numerous specific loci, one has a rich array of potential systems from which to select. Specific locus systems in higher plants could be used to assess the mutagenicity of single chemical compounds or combinations of chemical compounds. Depending on the circumstances, seeds and/or seedlings could be used; plants could be grown in situ in either containers or plots to assess the immediate environment for one or more mutagens over an extended period. Since plants are eucaryotes, data from such experiments could serve as one more source of information along with that obtained from a battery of other tests used in the tier system. PMID:367776

  8. Gravitropism in higher plant shoots. IV - Further studies on participation of ethylene

    NASA Technical Reports Server (NTRS)

    Wheeler, Raymond M.; White, Rosemary G.; Salisbury, Frank B.

    1986-01-01

    Various hypotheses regarding the influence of ethylene on gravitropism in higher plant shoots were experimentally tested. It was found that ethylene at 1.0 and 10.0 cu cm/cu m decreased the rate of gravitropic bending in cocklebur stems, while 0.1 cm/cu m of ethylene had little effect. Treating cocklebur plants with 1.0 mmol aminoethoxyvinylglycine (AVG, an ethylene synthesis inhibitor) delayed stem bending compared with controls, but adding 0.1 cu cm/cu m ethylene in the surrounding atmosphere partially restored the rate of bending of AVG-treated plants. Virtually all newly synthesized ethylene appeared in bottom halves of horizontal stems, where ethylene concentrations were as much as 100 times those in upright stems or in top halves of horizontal stems. Auxin applied to one side of a vertical stem caused extreme bending away from that side; gibberellic acid, kinetin, and abscisic acid were without effect.

  9. L-Ascorbate biosynthesis in higher plants: the role of VTC2

    PubMed Central

    Linster, Carole L.; Clarke, Steven G.

    2008-01-01

    In the past year, the last missing enzyme of the L-galactose pathway, the linear form of which appears to represent the major biosynthetic route to L-ascorbate (vitamin C) in higher plants, has been identified as a GDP-L-galactose phosphorylase. This enzyme catalyzes the first committed step in the synthesis of that vital antioxidant and enzyme cofactor. Here, we discuss how GDP-L-galactose phosphorylase enzymes, encoded in Arabidopsis by the paralogous VTC2 and VTC5 genes, function in concert with the other enzymes of the L-galactose pathway to provide plants the appropriate levels of L-ascorbate. We hypothesize that regulation of L-ascorbate biosynthesis might occur at more than one step and warrants further investigation to allow for the manipulation of vitamin C levels in plants. PMID:18824398

  10. How does plant chemical diversity contribute to biodiversity at higher trophic levels?

    PubMed

    Schuman, Meredith C; van Dam, Nicole M; Beran, Franziska; Harpole, W Stanley

    2016-04-01

    Plants, perhaps Earth's most accomplished chemists, produce thousands of specialized metabolites having no direct role in cell division or growth. These phytochemicals vary by taxon, with many taxa producing characteristic substance classes; and within taxa, with individual variation in structural variety and production patterns. Observations of corresponding variation in herbivore metabolism, behavior, and diet breadth motivated the development of chemical ecology research. We discuss the importance of plant biodiversity in general and phytochemical diversity in particular for biodiversity and ecological interactions at higher trophic levels. We then provide an overview of the descriptive, molecular and analytical tools which allow modern biologists to investigate phytochemical diversity and its effects on higher trophic levels, from physiological mechanisms to ecological communities. PMID:27436646

  11. Immunochemical characterization of NADPH-cytochrome P-450 reductase from Jerusalem artichoke and other higher plants.

    PubMed Central

    Benveniste, I; Lesot, A; Hasenfratz, M P; Durst, F

    1989-01-01

    Polyclonal antibodies were prepared against NADPH-cytochrome P-450 reductase purified from Jerusalem artichoke. These antibodies inhibited efficiently the NADPH-cytochrome c reductase activity of the purified enzyme, as well as of Jerusalem artichoke microsomes. Likewise, microsomal NADPH-dependent cytochrome P-450 mono-oxygenases (cinnamate and laurate hydroxylases) were efficiently inhibited. The antibodies were only slightly inhibitory toward microsomal NADH-cytochrome c reductase activity, but lowered NADH-dependent cytochrome P-450 mono-oxygenase activities. The Jerusalem artichoke NADPH-cytochrome P-450 reductase is characterized by its high Mr (82,000) as compared with the enzyme from animals (76,000-78,000). Western blot analysis revealed cross-reactivity of the Jerusalem artichoke reductase antibodies with microsomes from plants belonging to different families (monocotyledons and dicotyledons). All of the proteins recognized by the antibodies had an Mr of approx. 82,000. No cross-reaction was observed with microsomes from rat liver or Locusta migratoria midgut. The cross-reactivity generally paralleled well the inhibition of reductase activity: the enzyme from most higher plants tested was inhibited by the antibodies; whereas Gingko biloba, Euglena gracilis, yeast, rat liver and insect midgut activities were insensitive to the antibodies. These results point to structural differences, particularly at the active site, between the reductases from higher plants and the enzymes from phylogenetically distant plants and from animals. Images Fig. 5. PMID:2499315

  12. Role of Ca[sup ++]/calmodulin in the regulation of microtubules in higher plants

    SciTech Connect

    Cyr, R.

    1992-01-01

    The cytoskeleton including its microtubule (Mt) component participates in processes that directly affect growth and development in higher plants. Normal cytoskeletal function requires the precise and orderly arrangement of Mts into several cell cycle and developmentally specific arrays. The cortical array somehow directs the deposition of cellulose. Little molecular information is available regarding the formation of these arrays or the cellular signals to which they respond. Experimental data described here suggests that plant cells use calcium, in the form of a Ca[sup ++]/calmodulin complex, to affect the dynamics of Mts within the cortical array. Owing to the importance of Ca[sup ++] as a regulatory ion in higher plants we are probing for a putative Ca[sup ++]/Mt transduction pathway which may serve to integrate Mt activities within the growing and developing plant cell. We are using a lysed cell model in conjunction with immunocytochemical and biochemical methodologies to dissect how Ca[sup ++]/calmodulin interacts with Mts to affect their function.

  13. Consumption of carbonyl sulphide (COS) by higher plant carbonic anhydrase (CA)

    NASA Astrophysics Data System (ADS)

    Protoschill-Krebs, G.; Wilhelm, C.; Kesselmeier, J.

    Carbonic anhydrase (CA), isolated from pea leaves, was found to consume carbonyl sulphide (COS), a climatic relevant trace gas in the atmosphere. The isolated enzyme, free of other carboxylases, showed a very high affinity towards this substrate. The experiments confirm that CA is the key enzyme for the consumption of COS in higher plants. Furthermore, the identification of this enzyme furthers our understanding of additional sinks for COS, which are needed to understand the balance of known global sources.

  14. Excitation energy transfer in vitro between phycobiliproteins and thylakoid photosystem II of higher plants

    NASA Astrophysics Data System (ADS)

    Wu, Xiaonan; Tseng, C. K.

    1992-12-01

    The excitation energy transfer from phycobiliproteins to thylakoid PSII of higher plants was investigated. When incubated with spinach thylakoids, phycobiliproteins isolated from red and blue-green algae transferred light energy absorbed to spinach PSII. The efficiency of energy transfer was dependent on the kind of phycobiliproteins used. If spinach thylakoids were replaced by the thylakoids of Brassica chinensis, R-phycoerythin or C-phycocyanin did not transfer their excitation energy to PSII of Brassica chinensis unless allophycocyanin was present.

  15. A FastA based compilation of higher plant mitochondrial tRNA genes.

    PubMed Central

    Sagliano, A; Volpicella, M; Gallerani, R; Ceci, L R

    1998-01-01

    A new version of the compilation of higher plant mitochondrial tRNA genes (http://www.ebi.ac.uk/service ) has been obtained by means of the FastA program for similarity searching in nucleotide sequence Databases. This approach improves the previous collection, which was based on literature data analysis. The current compilation contains 158 sequences with an increase of 43 units. In this paper, some interesting features of the new entries are briefly presented. PMID:9399821

  16. Carbon dioxide and the stomatal control of water balance and photosynthesis in higher plants

    SciTech Connect

    Taiz, L.; Zeiger, E.; Mawson, B. T.; Cornish, K.; Radin, J. W.; Turcotte, E. L.; Hercovitz, S.; Tallman, G.; Karlsson, P. E.; Bogomolni, R. A.; Talbott, L. D.; Srivastava, A.

    1992-01-01

    Research continued into the investigation of the effects of carbon dioxide on stomatal control of water balance and photosynthesis in higher plants. Topics discussed this period include a method of isolating a sufficient number of guard cell chloroplasts for biochemical studies by mechanical isolation of epidermal peels; the measurement of stomatal apertures with a digital image analysis system; development of a high performance liquid chromatography method for quantification of metabolites in guard cells; and genetic control of stomatal movements in Pima cotton. (CBS)

  17. Higher plant modelling for life support applications: first results of a simple mechanistic model

    NASA Astrophysics Data System (ADS)

    Hezard, Pauline; Dussap, Claude-Gilles; Sasidharan L, Swathy

    2012-07-01

    In the case of closed ecological life support systems, the air and water regeneration and food production are performed using microorganisms and higher plants. Wheat, rice, soybean, lettuce, tomato or other types of eatable annual plants produce fresh food while recycling CO2 into breathable oxygen. Additionally, they evaporate a large quantity of water, which can be condensed and used as potable water. This shows that recycling functions of air revitalization and food production are completely linked. Consequently, the control of a growth chamber for higher plant production has to be performed with efficient mechanistic models, in order to ensure a realistic prediction of plant behaviour, water and gas recycling whatever the environmental conditions. Purely mechanistic models of plant production in controlled environments are not available yet. This is the reason why new models must be developed and validated. This work concerns the design and test of a simplified version of a mathematical model coupling plant architecture and mass balance purposes in order to compare its results with available data of lettuce grown in closed and controlled chambers. The carbon exchange rate, water absorption and evaporation rate, biomass fresh weight as well as leaf surface are modelled and compared with available data. The model consists of four modules. The first one evaluates plant architecture, like total leaf surface, leaf area index and stem length data. The second one calculates the rate of matter and energy exchange depending on architectural and environmental data: light absorption in the canopy, CO2 uptake or release, water uptake and evapotranspiration. The third module evaluates which of the previous rates is limiting overall biomass growth; and the last one calculates biomass growth rate depending on matter exchange rates, using a global stoichiometric equation. All these rates are a set of differential equations, which are integrated with time in order to provide

  18. Preliminary Modelling of Mass Flux at the Surface of Plant Leaves within the MELiSSA Higher Plant Compartments

    NASA Astrophysics Data System (ADS)

    Holmberg, Madeleine; Paille, Christel; Lasseur, Christophe

    The ESA project Micro Ecological Life Support System Alternative (MELiSSA) is an ecosystem of micro-organisms and higher plants, constructed with the objective of being operated as a tool to understand artificial ecosystems to be used for a long-term or permanent manned planetary base (e.g. Moon or Mars). The purpose of such a system is to provide for generation of food, water recycling, atmospheric regeneration and waste management within defined standards of quality and reliability. As MELiSSA consists of individual compartments which are connected to each other, the robustness of the system is fully dependent on the control of each compartment, as well as the flow management between them. Quality of consumables and reliability of the ecosystem rely on the knowledge, understanding and control of each of the components. This includes the full understanding of all processes related to the higher plants. To progress in that direction, this paper focuses on the mechanical processes driving the gas and liquid exchanges between the plant leaf and its environment. The process responsible for the mass transfer on the surface of plant leaves is diffusion. The diffusion flux is dependent on the behaviour of the stoma of the leaf and also on the leaf boundary layer (BL). In this paper, the physiology of the leaf is briefly examined in order to relate parameters such as light quality, light quantity, CO2 concentration, temperature, leaf water potential, humidity, vapour pressure deficit (VPD) gradients and pollutants to the opening or closing of stomata. The diffusion process is described theoretically and the description is compared to empirical approaches. The variables of the BL are examined and the effect airflow in the compartment has on the BL is investigated. Also presented is the impact changes in different environmental parameters may have on the fluid exchanges. Finally, some tests, to evaluate the accuracy of the concluded model, are suggested.

  19. Impact of common cytostatic drugs on pollen fertility in higher plants.

    PubMed

    Mišík, Miroslav; Kundi, Michael; Pichler, Clemens; Filipic, Metka; Rainer, Bernhard; Mišíková, Katarina; Nersesyan, Armen; Knasmueller, Siegfried

    2016-08-01

    Cytostatic drugs are among the most toxic chemicals which are produced. Many of them cause damage of the genetic material which may affect the fertility of higher organisms. To study the impact of the widely used anticancer drugs [cisplatin (CisPt), etoposide (Et), and 5-fluorouracil (5-FU)] on the reproduction of higher plants, pollen abortion experiments were conducted with species which belong to major plant families, namely with Tradescantia paludosa (Commelinaceae), Arabidopsis thaliana (Brassicaceae), Chelidonium majus (Papaveraceae), and Alisma plantago-aquatica (Alismataceae). All compounds increased the frequencies of abortive grains. The lowest effective doses were in general in a narrow range (i.e., 1 and 10 mg/kg of dry soil). The effects of the individual drugs were similar in T. paludosa, A. plantago-aquatica, and Ch. majus, while A. thaliana was consistently less sensitive. The highest abortion rate was obtained in most experiments with CisPt, followed by 5-FU and Et. Comparisons of the doses which caused effects in the present experiments in the different species with the predicted environment concentrations and with the levels of the cytostatics which were detected in hospital wastewaters show that the realistic environmental concentrations of the drugs are 4-6 orders of magnitude lower. Therefore, it is unlikely that these drugs affect the fertility of higher plants in aquatic and terrestrial ecosystems. PMID:25779110

  20. Boron uptake and accumulation by higher plants: A literature review: Final report

    SciTech Connect

    Sposito, G.; Calderone, S.J.

    1988-05-01

    This study provides a review of the literature on boron uptake and accumulation by higher plants, particularly trees. It addresses those aspects of the soil chemistry of boron that are most relevant to uptake by trees, then discusses the plant biochemistry of boron, its uptake and accumulation in plant tissue, and its phytotoxicity symptoms in plant species. The literature reviewed suggests that boron uptake is accomplished by a passive, massflow mechanism, as opposed to a metabolic process, with the most likely chemical form taken up being the neutral complex, H/sub 3/BO/sub 3/. The biochemical role of boron is not well understood, but evidence exists for its involvement with carbohydrate transformations and the control of growth-regulating compounds. Because of the mass-flow uptake mechanism, the distribution of boron in trees is connected intimately with the patterns of transpiration, which are species-dependent. Precise data on the effect of plant genotype on boron uptake, however, were not found in the published literature. The phytotoxicity symptoms of boron in trees also are species-dependent, although a consensus does exist as to the general nature of external symptoms and the basis of boron tolerance.

  1. Contrasting behavior of higher plant photosystem I and II antenna systems during acclimation.

    PubMed

    Ballottari, Matteo; Dall'Osto, Luca; Morosinotto, Tomas; Bassi, Roberto

    2007-03-23

    In this work we analyzed the photosynthetic apparatus in Arabidopsis thaliana plants acclimated to different light intensity and temperature conditions. Plants showed the ability to acclimate into different environments and avoid photoinhibition. When grown in high light, plants had a faster activation rate for energy dissipation (qE). This ability was correlated to higher accumulation levels of a specific photosystem II subunit, PsbS. The photosystem II antenna size was also regulated according to light exposure; smaller antenna size was observed in high light-acclimated plants with respect to low light plants. Different antenna polypeptides did not behave similarly, and Lhcb1, Lchb2, and Lhcb6 (CP24) are shown to undergo major levels of regulation, whereas Lhcb4 and Lhcb5 (CP29 and CP26) maintained their stoichiometry with respect to the reaction center in all growth conditions. The effect of acclimation on photosystem I antenna was different; in fact, the stoichiometry of any Lhca antenna proteins with respect to photosystem I core complex was not affected by growth conditions. Despite this stability in antenna stoichiometry, photosystem I light harvesting function was shown to be regulated through different mechanisms like the control of photosystem I to photosystem II ratio and the association or dissociation of Lhcb polypeptides to photosystem I. PMID:17229724

  2. The main goals of experiments with the higher plants in the project MARS - 500.

    NASA Astrophysics Data System (ADS)

    Sychev, Vladimir; Levinskikh, Margarita; Podolsky, Igor; Gushin, Vadim; Bingham, Gail; Bates, Scott

    At the present step of development of manned flight to Mars there is a current opinion that including a greenhouse in the composition of Life Support Systems (LSS) of Martian expedition would essentially improve a spacecraft habitat conditions and also would have impact to preventing of a number of possible consequences of continuous presence of human in artificial environment. Development of design objectives of future space greenhouses applicable for conditions of Martian expedition should be based, in our opinion, not only on the results of real space experiments, conducted onboard of orbital stations, but also on the results of ground-based experiments. In connection with above considerations there is a number of technological, biological and psychological experiments is planned to be conducted in the frame of MARS-500 project to resolve questions related to incorporation of higher plants in LSS of inter-planetary flights. The questions include: testing of developed elements of the greenhouse construction and methods for cultivation of vegetables under conditions of imitation of the flight of Martian expedition; selection of breeds and species of vegetables, characterized by high speed of biomass accumulation, attractive taste and appearance; investigation of growth, development and metabolism of plants under long-term continuous cultivation in manned pressurized object; comparison of the productivity of the plants as a function of utilization of different light source; determination of maximum amount of planted biomass of the plants and number of possible vegetation under conditions of long-term utilization of vegetation chamber of the greenhouse without substrate replacement; investigation of crops dietetic preferences of crew members; estimation of quality of plant biomass using seeding of the plants by microorganisms and nitrates and vitamins content as markers; development and approbation of methodical approaches to estimation of psychological factors of

  3. From Plants to Birds: Higher Avian Predation Rates in Trees Responding to Insect Herbivory

    PubMed Central

    Mäntylä, Elina; Alessio, Giorgio A.; Blande, James D.; Heijari, Juha; Holopainen, Jarmo K.; Laaksonen, Toni; Piirtola, Panu; Klemola, Tero

    2008-01-01

    Background An understanding of the evolution of potential signals from plants to the predators of their herbivores may provide exciting examples of co-evolution among multiple trophic levels. Understanding the mechanism behind the attraction of predators to plants is crucial to conclusions about co-evolution. For example, insectivorous birds are attracted to herbivore-damaged trees without seeing the herbivores or the defoliated parts, but it is not known whether birds use cues from herbivore-damaged plants with a specific adaptation of plants for this purpose. Methodology We examined whether signals from damaged trees attract avian predators in the wild and whether birds could use volatile organic compound (VOC) emissions or net photosynthesis of leaves as cues to detect herbivore-rich trees. We conducted a field experiment with mountain birches (Betula pubescens ssp. czerepanovii), their main herbivore (Epirrita autumnata) and insectivorous birds. Half of the trees had herbivore larvae defoliating trees hidden inside branch bags and half had empty bags as controls. We measured predation rate of birds towards artificial larvae on tree branches, and VOC emissions and net photosynthesis of leaves. Principal Findings and Significance The predation rate was higher in the herbivore trees than in the control trees. This confirms that birds use cues from trees to locate insect-rich trees in the wild. The herbivore trees had decreased photosynthesis and elevated emissions of many VOCs, which suggests that birds could use either one, or both, as cues. There was, however, large variation in how the VOC emission correlated with predation rate. Emissions of (E)-DMNT [(E)-4,8-dimethyl-1,3,7-nonatriene], β-ocimene and linalool were positively correlated with predation rate, while those of highly inducible green leaf volatiles were not. These three VOCs are also involved in the attraction of insect parasitoids and predatory mites to herbivore-damaged plants, which suggests that

  4. Formation of higher plant component microbial community in closed ecological system

    NASA Astrophysics Data System (ADS)

    Tirranen, L. S.

    2001-07-01

    Closed ecological systems (CES) place at the disposal of a researcher unique possibilities to study the role of microbial communities in individual components and of the entire system. The microbial community of the higher plant component has been found to form depending on specific conditions of the closed ecosystem: length of time the solution is reused, introduction of intrasystem waste water into the nutrient medium, effect of other component of the system, and system closure in terms of gas exchange. The higher plant component formed its own microbial complex different from that formed prior to closure. The microbial complex of vegetable polyculture is more diverse and stable than the monoculture of wheat. The composition of the components' microflora changed, species diversity decreased, individual species of bacteria and fungi whose numbers were not so great before the closure prevailed. Special attention should be paid to phytopathogenic and conditionally pathogenic species of microorganisms potentially hazardous to man or plants and the least controlled in CES. This situation can endanger creation of CES and make conjectural existence of preplanned components, man, specifically, and consequently, of CES as it is.

  5. Roles of Organic Acid Anion Secretion in Aluminium Tolerance of Higher Plants

    PubMed Central

    Yang, Lin-Tong; Qi, Yi-Ping; Jiang, Huan-Xin; Chen, Li-Song

    2013-01-01

    Approximately 30% of the world's total land area and over 50% of the world's potential arable lands are acidic. Furthermore, the acidity of the soils is gradually increasing as a result of the environmental problems including some farming practices and acid rain. At mildly acidic or neutral soils, aluminium(Al) occurs primarily as insoluble deposits and is essentially biologically inactive. However, in many acidic soils throughout the tropics and subtropics, Al toxicity is a major factor limiting crop productivity. The Al-induced secretion of organic acid (OA) anions, mainly citrate, oxalate, and malate, from roots is the best documented mechanism of Al tolerance in higher plants. Increasing evidence shows that the Al-induced secretion of OA anions may be related to the following several factors, including (a) anion channels or transporters, (b) internal concentrations of OA anions in plant tissues, (d) temperature, (e) root plasma membrane (PM) H+-ATPase, (f) magnesium (Mg), and (e) phosphorus (P). Genetically modified plants and cells with higher Al tolerance by overexpressing genes for the secretion and the biosynthesis of OA anions have been obtained. In addition, some aspects needed to be further studied are also discussed. PMID:23509687

  6. Roles of organic acid anion secretion in aluminium tolerance of higher plants.

    PubMed

    Yang, Lin-Tong; Qi, Yi-Ping; Jiang, Huan-Xin; Chen, Li-Song

    2013-01-01

    Approximately 30% of the world's total land area and over 50% of the world's potential arable lands are acidic. Furthermore, the acidity of the soils is gradually increasing as a result of the environmental problems including some farming practices and acid rain. At mildly acidic or neutral soils, aluminium (Al) occurs primarily as insoluble deposits and is essentially biologically inactive. However, in many acidic soils throughout the tropics and subtropics, Al toxicity is a major factor limiting crop productivity. The Al-induced secretion of organic acid (OA) anions, mainly citrate, oxalate, and malate, from roots is the best documented mechanism of Al tolerance in higher plants. Increasing evidence shows that the Al-induced secretion of OA anions may be related to the following several factors, including (a) anion channels or transporters, (b) internal concentrations of OA anions in plant tissues, (d) temperature, (e) root plasma membrane (PM) H(+)-ATPase, (f) magnesium (Mg), and (e) phosphorus (P). Genetically modified plants and cells with higher Al tolerance by overexpressing genes for the secretion and the biosynthesis of OA anions have been obtained. In addition, some aspects needed to be further studied are also discussed. PMID:23509687

  7. Assessment of organochlorine pesticides residues in higher plants from oil exploration areas of Niger Delta, Nigeria.

    PubMed

    Sojinu, O Samuel; Sonibare, Oluwadayo O; Ekundayo, Olusegun O; Zeng, Eddy Y

    2012-09-01

    The concentrations and distributions of organochlorine pesticides (OCPs) in some higher plant samples collected from oil exploration areas of the Niger Delta, Nigeria were examined. The concentrations of Σ(25)OCP ranged from 82 to 424, 44 to 200 , 34 to 358, 33 to 106 and 16 to 75 ng/g in Olomoro, Oginni, Uzere, Irri and Calabar plants, respectively. The compositional profiles of the analysed OCPs in most of the plants showed no fresh inputs in the area. The OCPs detected in the samples could have resulted from pesticide usage for intense farming activities cum the use of pesticides to control household pests and insects in the area. Drilling fluids and corrosion inhibitors used in petroleum explorations also have chlorinated compounds as additives thereby serving as potential sources of OCPs. Among the studied plants, elephant grass showed high bioaccumulation and phytoremediation potentials of OCPs. The ΣHCH concentrations exceeded the allowable daily intake limit thereby serving as potential threat to humans. PMID:22789817

  8. Risk assessment for selected xenobiotics by bioassay methods with higher plants

    NASA Astrophysics Data System (ADS)

    Günther, Petra; Pestemer, Wilfried

    1990-05-01

    Different bioassays with higher plants were approved for use in a bioassay procedure for testing of xenobiotics according to the German Chemicals Act. Selected environmental pollutants (atrazine, cadmium chloride, 2,6-dichlorobenzonitrile, pentachlorophenol, potassium dichromate, thiourea), all from a list of reference chemicals, were tested with these methods. Dose-response curves for growth of oats and turnips were evaluated in soil and vermiculite (nonsorptive substrate), and availability to plants was calculated by comparing the EC50 values for one chemical in both substrates. The most active chemical was atrazine, followed by 2,6-dichlorobenzonitrile, pentachlorophenol, potassium dichromate, cadmium chloride, and thiourea. The least available compound to plants was pentachlorophenol, tested with turnips ( Brassica rapa var. rapa). The strongest inhibition of germination, demonstrated in an in vitro assay with garden cress ( Lepidium sativum), was found with 2,6-dichlorobenzonitrile, the lowest with atrazine. The effect of an extended exposure of the plants to the chemicals was evaluated in a long-term bioassay with oats ( Avena sativa) in hydroponic culture. Several dose-response curves during the growing period were derived. It was found that the EC50 values for atrazine and thiourea decreased markedly during the first four weeks; thereafter the changes were much smaller. As an overall conclusion, a bioassay procedure is proposed that can be included in the graduated plan recommended by the German Chemicals Act.

  9. Characterization of thylakoid lipid membranes from cyanobacteria and higher plants by molecular dynamics simulations.

    PubMed

    van Eerden, Floris J; de Jong, Djurre H; de Vries, Alex H; Wassenaar, Tsjerk A; Marrink, Siewert J

    2015-06-01

    The thylakoid membrane is mainly composed of non-common lipids, so called galactolipids. Despite the importance of these lipids for the function of the photosynthetic reaction centers, the molecular organization of these membranes is largely unexplored. Here we use multiscale molecular dynamics simulations to characterize the thylakoid membrane of both cyanobacteria and higher plants. We consider mixtures of up to five different galactolipids plus phosphatidylglycerol to represent these complex membranes. We find that the different lipids generally mix well, although nanoscale heterogeneities are observed especially in case of the plant membrane. The fluidity of the cyanobacterial membrane is markedly reduced compared to the plant membrane, even considering elevated temperatures at which thermophilic cyanobacteria are found. We also find that the plant membrane more readily undergoes a phase transformation to an inverted hexagonal phase. We furthermore characterized the conformation and dynamics of the cofactors plastoquinone and plastoquinol, revealing of the fast flip-flop rates for the non-reduced form. Together, our results provide a molecular view on the dynamical organization of the thylakoid membrane. PMID:25749153

  10. Analysis of Polyamines in Higher Plants by High Performance Liquid Chromatography 1

    PubMed Central

    Flores, Hector E.; Galston, Arthur W.

    1982-01-01

    A sensitive (0.01-1 nmol) method has been developed for the analysis of polyamines in higher plant extracts based on high performance liquid chromatography (HPLC) of their benzoyl derivatives (Redmond, Tseng 1979 J Chromatogr 170: 479-481). Putrescine, cadaverine, agmatine, spermidine, spermine, and the less common polyamines nor-spermidine and homospermidine can be completely resolved by reverse phase HPLC, isocratic elution with methanol:water (64%, v/v) through a 5-μm C18 column, and detection at 254 nm. The method can be directly applied to crude plant extracts, and it is not subject to interference by carbohydrates and phenolics. A good quantitative correlation was found between HPLC analysis of benzoylpolyamines and thin layer chromatography of their dansyl derivatives. With the HPLC method, polyamine titers have been reproducibly estimated for various organs of amaranth, Lemna, oat, pea, Pharbitis, and potato. The analyses correlate well with results of thin layer chromatography determinations. Images PMID:16662279

  11. Regulation of chloroplast number and DNA synthesis in higher plants. Final report

    SciTech Connect

    Mullet, J.E.

    1995-11-10

    The long term objective of this research is to understand the process of chloroplast development and its coordination with leaf development in higher plants. This is important because the photosynthetic capacity of plants is directly related to leaf and chloroplast development. This research focuses on obtaining a detailed description of leaf development and the early steps in chloroplast development including activation of plastid DNA synthesis, changes in plastid DNA copy number, activation of chloroplast transcription and increases in plastid number per cell. The grant will also begin analysis of specific biochemical mechanisms by isolation of the plastid DNA polymerase, and identification of genetic mutants which are altered in their accumulation of plastid DNA and plastid number per cell.

  12. Regulation of chloroplast number and DNA synthesis in higher plants. Final report

    SciTech Connect

    Mullet, J.E.

    1995-11-10

    The long term objective of this research is to understand the process of chloroplast development and its coordination with leaf development in higher plants. This is important because the photosynthetic capacity of plants is directly related to leaf and chloroplast development. This research focuses on obtaining a detailing description of leaf development and the early steps in chloroplast development including activation of plastid DNA synthesis, changes in plastid DNA copy number, activation of chloroplast transcription and increases in plastid number per cell. The grant will also begin analysis of specific biochemical mechanisms by isolation of the plastid DNA polymerase, and identification of genetic mutants which are altered in their accumulation of plastid DNA and plastid number per cell.

  13. 7 CFR 955.90 - Counterparts.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 8 2014-01-01 2014-01-01 false Counterparts. 955.90 Section 955.90 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE VIDALIA ONIONS GROWN IN...

  14. 7 CFR 955.90 - Counterparts.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Counterparts. 955.90 Section 955.90 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE VIDALIA ONIONS GROWN IN...

  15. 7 CFR 955.90 - Counterparts.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 8 2012-01-01 2012-01-01 false Counterparts. 955.90 Section 955.90 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE VIDALIA ONIONS GROWN IN...

  16. 7 CFR 955.90 - Counterparts.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 8 2011-01-01 2011-01-01 false Counterparts. 955.90 Section 955.90 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE VIDALIA ONIONS GROWN IN...

  17. 7 CFR 955.90 - Counterparts.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 8 2013-01-01 2013-01-01 false Counterparts. 955.90 Section 955.90 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE VIDALIA ONIONS GROWN IN...

  18. 50 CFR 402.04 - Counterpart regulations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 9 2011-10-01 2011-10-01 false Counterpart regulations. 402.04 Section 402.04 Wildlife and Fisheries JOINT REGULATIONS (UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE INTERIOR AND NATIONAL MARINE FISHERIES SERVICE, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE); ENDANGERED...

  19. Seed sprout production: Consumables and a foundation for higher plant growth in space

    NASA Technical Reports Server (NTRS)

    Day, Michelle; Thomas, Terri; Johnson, Steve; Luttges, Marvin

    1990-01-01

    Seed sprouts can be produced as a source of fresh vegetable materials and as higher plant seedlings in space. Sprout production was undertaken to evaluate the mass accumulations possible, the technologies needed, and the reliability of the overall process. Baseline experiments corroborated the utility of sprout production protocols for a variety of seed types. The automated delivery of saturated humidity effectively supplants labor intensive manual soaking techniques. Automated humidification also lend itself to modest centrifugal sprout growth environments. A small amount of ultraviolet radiation effectively suppressed bacterial and fungal contamination, and the sprouts were suitable for consumption.

  20. Studies on the chalcone synthase gene of two higher plants: petroselinum hortense and matthiola incana

    SciTech Connect

    Hemleben, V.; Frey, M.; Rall, S.; Koch, M.; Kittel, M.; Kreuzaler, F.; Ragg, H.; Fautz, E.; Hahlbrock, K.

    1982-01-01

    Two higher plant systems are presented which allow to study coordinated gene expression of the light-induced metabolic pathway of flavonoid biosynthesis: tissue culture cells of Petroselinum hortense (Apiaceae) and different developmental stages of various genotypes of Matthiola incana (Brassicaceae). The gene structure of the chalcone synthase is mainly studied. A cDNA clone (pLF56) of parsley has been constructed and characterized conferring the chalcone synthase gene sequence. Strong cross hybridization between the parsley cDNA and Matthiola DNA allowed to identify a HindIII fragment (6000 bp) identical in size for parsley and different Matthiola wild type lines and a mutant line.

  1. The carbon isotope composition of ancient CO2 based on higher-plant organic matter.

    PubMed

    Gröcke, Darren R

    2002-04-15

    Carbon isotope ratios in higher-plant organic matter (delta(13)C(plant)) have been shown in several studies to be closely related to the carbon isotope composition of the ocean-atmosphere carbon reservoir, and, in particular, the isotopic composition of CO(2). These studies have primarily been focused on geological intervals in which major perturbations occur in the oceanic carbon reservoir, as documented in organic carbon and carbonates phases (e.g. Permian-Triassic and Triassic-Jurassic boundary, Early Toarcian, Early Aptian, Cenomanian-Turonian boundary, Palaeocene-Eocene Thermal Maximum (PETM)). All of these events, excluding the Cenomanian-Turonian boundary, record negative carbon isotope excursions, and many authors have postulated that the cause of such excursions is the massive release of continental-margin marine gas-hydrate reservoirs (clathrates). Methane has a very negative carbon isotope composition (delta(13)C, ca. 60 per thousand ) in comparison with higher-plant and marine organic matter, and carbonate. The residence time of methane in the ocean-atmosphere reservoir is short (ca. 10 yr) and is rapidly oxidized to CO(2), causing the isotopic composition of CO(2) to become more negative from its assumed background value (delta(13)C, ca. -7 per thousand ). However, to date, only the Early Toarcian, Early Aptian and PETM are well-constrained chronometric sequences that could attribute clathrate release as a viable cause to create such rapid negative delta(13)C excursions. Notwithstanding this, the isotopic analysis of higher-plant organic matter (e.g. charcoal, wood, leaves, pollen) has the ability to (i) record the isotopic composition of palaeoatmospheric CO(2) in the geological record, (ii) correlate marine and non-marine stratigraphic successions, and (iii) confirm that oceanic carbon perturbations are not purely oceanographic in their extent and affect the entire ocean-atmosphere system. A case study from the Isle of Wight, UK, indicates that the

  2. Light-regulated, tissue-specific immunophilins in a higher plant.

    PubMed

    Luan, S; Albers, M W; Schreiber, S L

    1994-02-01

    In addition to their application in organ transplantation, immunosuppressive drugs are valuable tools for studying signal transduction in eukaryotic cells. Using affinity chromatography, we have purified immunosuppressive drug receptors (immunophilins) from fava bean. Proteins belonging to both major classes of the immunophilin family identified from animal sources [FK506- and rapamycin-binding proteins (FKBPs) and cyclophilins] were present in this higher plant. FKBP13, the most abundant FKBP family member in leaf tissues, was not detected in root tissues, whereas other FKBPs were present in both tissues. While the abundance of cyclophilin A in leaves was similar to that in roots, cyclophilin B/C was expressed at a much higher level in leaf tissues than in root tissues. Subcellular localization of immunophilins in mesophyll cells showed that chloroplasts contained FKBP13 and cyclophilin B/C but not other members, which explains the preferential expression of these two proteins in leaves over roots. The abundance of chloroplast-localized immunophilins, FKBP13 and cyclophilin B/C, was regulated by light. Although etiolated leaves produced detectable levels of cyclophilin B/C, they did not express FKBP13. Illumination of etiolated plants dramatically increased the expression of both FKBP13 and cyclophilin B/C. The light-induced expression of FKBP13 is closely correlated with the accumulation of chlorophyll in the leaf tissue. Our findings suggest that FKBP13 and cyclophilin B/C may play a specific role in chloroplasts. PMID:7508125

  3. Mutational analysis of a higher plant antenna protein provides identification of chromophores bound into multiple sites

    PubMed Central

    Bassi, Roberto; Croce, Roberta; Cugini, Daniela; Sandonà, Dorianna

    1999-01-01

    The chromophore-binding properties of the higher plant light-harvesting protein CP29 have been studied by using site-directed mutagenesis of pigment-binding residues. Overexpression of the apoproteins in bacteria was followed by reconstitution in vitro with purified pigments, thus obtaining a family of mutant CP29 proteins lacking individual chromophore-binding sites. Biochemical characterization allowed identification of the eight porphyrins and two xanthophyll-binding sites. It is shown that the four porphyrin-binding sites (A1, A2, A4, and A5) situated in the central, twofold-symmetrical domain of the protein are selective for Chl-a, whereas the four peripheral sites (A3, B3, B5, and B6) have mixed Chl-a–Chl-b specificity. Within a site, porphyrin coordination by glutamine increases affinity for Chl-b as compared with glutamate. Xanthophyll site L1 is occupied by lutein, whereas site L2 can bind violaxanthin or neoxanthin. The protein is relatively stable when site L2 site is empty, suggesting that xanthophylls can be exchanged during operation of xanthophyll cycle-dependent photoprotection mechanism. Differential absorption spectroscopy allowed determination of transition energy levels for individual chromophores, thus opening the way to calculation of energy-transfer rates between Chl in higher plant antenna proteins. PMID:10468561

  4. [Study of the compatibility of certain higher plants and chlorella used as a bioregenerative human life support system].

    PubMed

    Shaĭdorov, Iu I; Shebalin, B N; Meleshko, G I

    1980-01-01

    The phototrophic component of a bioregenerative life support system should be of a multispecies structure. It should incorporate not only higher plants but also different algae. The paper discusses the studies concerning mutual effects of Chlorella and higher plants cultivated together in a closed atmosphere. It can be inferred from the studies that gaseous products of Chlorella did not exert a significant effect on the carbon dioxide consumption by wheat and radish plants or on their biomass increment. In turn, gaseous products of higher plants did not influence Chlorella growth. It can, therefore, be concluded that Chlorella and the above higher plants, when cultivated in a common atmosphere, do not inhibit each other and can be regarded as biologically compatible constituents of the photoautotrophic component of future bioregenerative life support systems. PMID:6104747

  5. Introducing an algal carbon-concentrating mechanism into higher plants: location and incorporation of key components.

    PubMed

    Atkinson, Nicky; Feike, Doreen; Mackinder, Luke C M; Meyer, Moritz T; Griffiths, Howard; Jonikas, Martin C; Smith, Alison M; McCormick, Alistair J

    2016-05-01

    Many eukaryotic green algae possess biophysical carbon-concentrating mechanisms (CCMs) that enhance photosynthetic efficiency and thus permit high growth rates at low CO2 concentrations. They are thus an attractive option for improving productivity in higher plants. In this study, the intracellular locations of ten CCM components in the unicellular green alga Chlamydomonas reinhardtii were confirmed. When expressed in tobacco, all of these components except chloroplastic carbonic anhydrases CAH3 and CAH6 had the same intracellular locations as in Chlamydomonas. CAH6 could be directed to the chloroplast by fusion to an Arabidopsis chloroplast transit peptide. Similarly, the putative inorganic carbon (Ci) transporter LCI1 was directed to the chloroplast from its native location on the plasma membrane. CCP1 and CCP2 proteins, putative Ci transporters previously reported to be in the chloroplast envelope, localized to mitochondria in both Chlamydomonas and tobacco, suggesting that the algal CCM model requires expansion to include a role for mitochondria. For the Ci transporters LCIA and HLA3, membrane location and Ci transport capacity were confirmed by heterologous expression and H(14) CO3 (-) uptake assays in Xenopus oocytes. Both were expressed in Arabidopsis resulting in growth comparable with that of wild-type plants. We conclude that CCM components from Chlamydomonas can be expressed both transiently (in tobacco) and stably (in Arabidopsis) and retargeted to appropriate locations in higher plant cells. As expression of individual Ci transporters did not enhance Arabidopsis growth, stacking of further CCM components will probably be required to achieve a significant increase in photosynthetic efficiency in this species. PMID:26538195

  6. Electromagnetic Counterparts to Black Hole Mergers

    NASA Technical Reports Server (NTRS)

    Schnittman, Jeremy D.

    2011-01-01

    During the final moments of a binary black hole (BH) merger, the gravitational wave (GW) luminosity of the system is greater than the combined electromagnetic (EM) output of the entire observable universe. However, the extremely weak coupling between GWs and ordinary matter makes these waves very difficult to detect directly. Fortunately, the inspirating BH system will interact strongly-on a purely Newtonian level-with any surrounding material in the host galaxy, and this matter can in turn produce unique EM signals detectable at Earth. By identifying EM counterparts to GW sources, we will be able to study the host environments of the merging BHs, in turn greatly expanding the scientific yield of a mission like LISA. Here we present a comprehensive review of the recent literature on the subject of EM counterparts, as well as a discussion of the theoretical and observational advances required to fully realize the scientific potential of the field.

  7. Some effects of high- gradient magnetic field on tropism of roots of higher plants

    NASA Astrophysics Data System (ADS)

    Kondrachuk, A.; Belyavskaya, N.

    The perception of gravity in living organisms is mostly based on the response of the gravisensing system to displacement of some specific mass caused by gravitational force. According to the starch-statolith hypothesis the amyloplasts play the role of specific mass in gravisensing cells of higher plants. Kuznetsov & Hasenstein (1996) have demonstrated that the high-gradient magnetic field (HGMF) exerts a directional ponderomotive force on diamagnetic substances, in particular, statoliths. This effect of the HGMF causes root response similar to that produced by the change in gravity vector. Their studies supported the starch-statolith hypothesis and showed that ponderomotive force can be used to modify force acting on statoliths by manipulating statolith locations within gravisensing cells. We have designed the HGMF facility that allows for generating the HGMF and analyzing its effects on higher plants' roots. It records by videosystem and measures with the help of image analysis software the parameters of kinetics of root bending under both the HGMF action and gravistimulation. Two species of plants (pea and cress) have been examined. The main results of the work are the following: 1) The magnetotropic effect of HGMF on root growth was found for both species. 2) The critical value of ponderomotive force that caused the magnetotropic effect was estimated by modeling the magnetic field spatial distribution in the region of root apex. 3) The electron-microscopic analysis of statocytes after the HGMF treatment was carried out. The displacement of amyloplasts in root statocytes of two species of plants in HGMF was firstly demonstrated at the ultrastructural level. 4) Spatial distribution of exogenous proton fluxes (pH) along the roots was studied. The changes in pH distribution along curvature zone and apices of roots were revealed in the HGMF. It is known that application of HGMFs or strong uniform magnetic fields may influence ion transport due to Ampere force. It

  8. Isotopic discrimination of zinc during root-uptake and cellular incorporation in higher plants

    NASA Astrophysics Data System (ADS)

    Mason, T. F.; Weiss, D. J.; Coles, B. J.; Horstwood, M.; Parrish, R. R.; Zhao, F. J.; Kirk, G. J.

    2003-04-01

    Introduction: Isotopic variability of terrestrial zinc offers a unique tool for studying the geochemical and biochemical cycling of zinc through natural ecosystems. However, to realise this potential, the mechanisms controlling the isotopic composition of zinc during geosphere-biosphere interactions must first be understood. The uptake of zinc by plants involves a variety of abiotic and biochemical reactions, and can provide insights into the types of processes that may fractionate zinc isotopes within living systems. We therefore present an experimental study to quantify if and how zinc isotopes are fractionated during uptake in higher plants. Methodology: Two experimental approaches were taken: (1) a hydroponic study in which rice, lettuce, and tomato cultivars were grown in one of two nutrient solutions (a HEDTA + NTA buffered system, and an EDTA buffered system), and (2) a field-based study in which rice plants were grown in experimental paddy fields under both zinc-sufficient and zinc-deficient conditions. Upon harvest, roots, shoots, nutrient solutions and soils were acid digested, and matrix components were removed from the zinc fraction using anion exchange procedures. For soils the 'bioavailble' zinc fraction was abstracted using a 1 N HCl leaching step. Zinc isotopic compositions were determined on a ThermoElemental Axiom MC-ICP-MS, using copper as an internal reference to correct for mass discrimination effects. Combined measurement errors based on repeated analyses of ultra-pure standards and plant reference materials were <0.035 ppm per atomic mass unit (pamu) (2σ) for 66Zn/64Zn measurements. Results: Under hydroponic condisions, all three plant species exhibit a similar pattern of zinc isotopic discrimination, with a small enrichment from nutrient solution to root of +0.04 to +0.09 ppm pamu, followed by an isotopic depletion from root to shoot of -0.13 to -0.26 ppm pamu. While the same trend is observed with the HEDTA + NTA and EDTA nutrient

  9. Higher plant Ca(2+)-ATPase: primary structure and regulation of mRNA abundance by salt.

    PubMed Central

    Wimmers, L E; Ewing, N N; Bennett, A B

    1992-01-01

    Calcium-dependent regulatory mechanisms participate in diverse developmentally, hormonally, and environmentally regulated processes, with the precise control of cytosolic Ca2+ concentration being critical to such mechanisms. In plant cells, P-type Ca(2+)-ATPases localized in the plasma membrane and the endoplasmic reticulum are thought to play a central role in regulating cytoplasmic Ca2+ concentrations. Ca(2+)-ATPase activity has been identified in isolated plant cell membranes, but the protein has not been characterized at the molecular level. We have isolated a partial-length cDNA (LCA1) and a complete genomic clone (gLCA13) encoding a putative endoplasmic reticulum-localized Ca(2+)-ATPase in tomato. The deduced amino acid sequence specifies a protein (Lycopersicon Ca(2+)-ATPase) of 1048 amino acids with a molecular mass of 116 kDa, eight probable transmembrane domains, and all of the highly conserved functional domains common to P-type cation-translocating ATPases. In addition, the protein shares approximately 50% amino acid sequence identify with animal sarcoplasmic/endoplasmic reticulum Ca(2+)-ATPases but less than 30% identity with other P-type ATPases. Genomic DNA blot hybridization analysis indicates that the Lycopersicon Ca(2+)-ATPase is encoded by a single gene. RNA blot hybridization analysis indicates the presence of three transcript sizes in root tissue and a single, much less abundant, transcript in leaves. Lycopersicon Ca(2+)-ATPase mRNA levels increase dramatically upon a 1-day exposure to 50 mM NaCl. Thus this report describes the primary structure of a higher-plant Ca(2+)-ATPase and the regulation of its mRNA abundance by salt stress. Images PMID:1384045

  10. Glycerophosphocholine Metabolism in Higher Plant Cells. Evidence of a New Glyceryl-Phosphodiester Phosphodiesterase

    PubMed Central

    van der Rest, Benoît; Boisson, Anne-Marie; Gout, Elisabeth; Bligny, Richard; Douce, Roland

    2002-01-01

    Glycerophosphocholine (GroPCho) is a diester that accumulates in different physiological processes leading to phospholipid remodeling. However, very little is known about its metabolism in higher plant cells. 31P-Nuclear magnetic resonance spectroscopy and biochemical analyses performed on carrot (Daucus carota) cells fed with GroPCho revealed the existence of an extracellular GroPCho phosphodiesterase. This enzymatic activity splits GroPCho into sn-glycerol-3-phosphate and free choline. In vivo, sn-glycerol-3-phosphate is further hydrolyzed into glycerol and inorganic phosphate by acid phosphatase. We visualized the incorporation and the compartmentation of choline and observed that the major choline pool was phosphorylated and accumulated in the cytosol, whereas a minor fraction was incorporated in the vacuole as free choline. Isolation of plasma membranes, culture medium, and cell wall proteins enabled us to localize this phosphodiesterase activity on the cell wall. We also report the existence of an intracellular glycerophosphodiesterase. This second activity is localized in the vacuole and hydrolyzes GroPCho in a similar fashion to the cell wall phosphodiesterase. Both extra- and intracellular phosphodiesterases are widespread among different plant species and are often enhanced during phosphate deprivation. Finally, competition experiments on the extracellular phosphodiesterase suggested a specificity for glycerophosphodiesters (apparent Km of 50 μm), which distinguishes it from other phosphodiesterases previously described in the literature. PMID:12226504

  11. A role for ethylene in the metabolism of cyanide by higher plants

    SciTech Connect

    Goudey, J.S.; Tittle, F.L.; Spencer, M.S. )

    1989-04-01

    The action of ethylene on the capacity of plant tissues to metabolize cyanice to {beta}-cyanoalanine was examined. Beta-cyanoalanine synthase catalyzes the reaction between cyanide and cysteine to form {beta}-cyanoalanine and hydrogen sulfide. Levels of {beta}-cyanoalanine synthase activity in tissues of 6 day old etiolated pea (Pisum sativum) seedlings were enhanced severalfold by 1 microliter per liter ethylene. The promotive effect of ethylene increased with increasing ethylene concentrations from 0.01 to 100 microliters per liter and with the period of exposure from 3 to 24 hours. Ethylene enhanced {beta}-cyanoalanine synthase activity in all regions of the seedling (shoots and roots, internodal regions, cotyledons). The promotive effect was eliminated by norbornadiene, a competitive inhibitor of ethylene action. Levels of {beta}-cyanoalanine synthase in seedlings of four other dicots (Phaseolus aureas, Glycine max, Lactuca sativa, Sinapis arvensis) and two monocots (Hordeum vulgares, Triticum aestivum) were also increased in response to ethylene. Our results suggest an important regulatory role for ethylene in the metabolism of cyanide by higher plants.

  12. Growth and development in higher plants under simulated microgravity conditions on a 3-dimensional clinostat

    NASA Astrophysics Data System (ADS)

    Shimazu, T.; Yuda, T.; Miyamoto, K.; Yamashita, M.; Ueda, J.

    Growth and development of etiolated pea (Pisum sativum L. cv. Alaska) and maize (Zea mays L. cv. Golden Cross Bantam) seedlings grown under simulated microgravity conditions were intensively studied using a 3-dimensional clinostat as a simulator of weightlessness. Epicotyls of etiolated pea seedlings grown on the clinostat were the most oriented toward the direction far from cotyledons. Mesocotyls of etiolated maize seedlings grew at random and coleoptiles curved slightly during clinostat rotation. Clinostat rotation promoted the emergence of the 3rd internodes in etiolated pea seedlings, while it significantly inhibited the growth of the 1st internodes. In maize seedlings, the growth of coleoptiles was little affected by clinostat rotation, but that of mesocotyls was suppressed, and therefore, the emergence of the leaf out of coleoptile was promoted. Clinostat rotation reduced the osmotic concentration in the 1st internodes of pea seedlings, although it has little effect on the 2nd and the 3rd internodes. Clinostat rotation also reduced the osmotic concentrations in both coleoptiles and mesocotyls of maize seedlings. Cell-wall extensibilities of the 1st and the 3rd internodes of pea seedlings grown on the clinostat were significantly lower and higher as compared with those on 1 g conditions, respectively. Cell-wall extensibility of mesocotyls in seedlings grown on the clinostat also decreased. Changes in cell wall properties seem to be well correlated to the growth of each organ in pea and maize seedlings. These results suggest that the growth and development of plants is controlled under gravity on earth, and that the growth responses of higher plants to microgravity conditions are regulated by both cell-wall mechanical properties and osmotic properties of stem cells.

  13. Plant Biology Personnel and Training at Doctorate-Granting Institutions. Higher Education Surveys Report. Survey Number 13.

    ERIC Educational Resources Information Center

    Chaney, Bradford; And Others

    A survey instrument was sent to all doctorate-granting institutions and all institutions identified as offering doctorates in plant biology. Doctorate-granting institutions were identified using the U.S. Department of Education's Higher Education General Information Surveys (HEGIS) listings. Responses were received from plant biology program…

  14. A Role for Shoot Protein in Shoot–Root Dry Matter Allocation in Higher Plants

    PubMed Central

    ANDREWS, M.; RAVEN, J. A.; LEA, P. J.; SPRENT, J. I.

    2006-01-01

    • Background and Aims It is stated in many recent publications that nitrate (\\documentclass[10pt]{article} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{pmc} \\usepackage[Euler]{upgreek} \\pagestyle{empty} \\oddsidemargin -1.0in \\begin{document} \\begin{equation*}{\\mathrm{NO}}_{3}^{-}\\end{equation*}\\end{document}) acts as a signal to regulate dry matter partitioning between the shoot and root of higher plants. Here we challenge this hypothesis and present evidence for the viewpoint that \\documentclass[10pt]{article} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{pmc} \\usepackage[Euler]{upgreek} \\pagestyle{empty} \\oddsidemargin -1.0in \\begin{document} \\begin{equation*}{\\mathrm{NO}}_{3}^{-}\\end{equation*}\\end{document} and other environmental effects on the shoot : root dry weight ratio (S:R) of higher plants are often related mechanistically to changes in shoot protein concentration. • Methods The literature on environmental effects on S:R is reviewed, focusing on relationships between S:R, growth and leaf \\documentclass[10pt]{article} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{pmc} \\usepackage[Euler]{upgreek} \\pagestyle{empty} \\oddsidemargin -1.0in \\begin{document} \\begin{equation*}{\\mathrm{NO}}_{3}^{-}\\end{equation*}\\end{document} and protein concentrations. A series of experiments carried out to test the proposal that S:R is dependent on shoot protein concentration is highlighted and new data are presented for tobacco (Nicotiana tabacum). • Key Results/Evidence Results from the literature and new data for tobacco show that S:R and leaf \\documentclass[10pt]{article} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage

  15. Concepts, strategies and potentials using hypo-g and other features of the space environment for commercialization using higher plants

    NASA Technical Reports Server (NTRS)

    Krikorian, A. D.

    1985-01-01

    Opportunities for releasing, capturing, constructing and/or fixing the differential expressions or response potentials of the higher plant genome in the hypo-g environment for commercialization are explored. General strategies include improved plant-growing, crop and forestry production systems which conserve soil, water, labor and energy resources, and nutritional partitioning and mobilization of nutrients and synthates. Tissue and cell culture techniques of commercial potential include the growing and manipulation of cultured plant cells in vitro in a bioreactor to produce biologicals and secondary plants of economic value. The facilitation of plant breeding, the cloning of specific pathogen-free materials, the elimination of growing point or apex viruses, and the increase of plant yield are other O-g applications. The space environment may be advantageous in somatic embryogenesis, the culture of alkaloids, and the development of completely new crop plant germ plasm.

  16. Extragalactic counterparts to Einstein slew survey sources

    NASA Technical Reports Server (NTRS)

    Schachter, Jonathan F.; Elvis, Martin; Plummer, David; Remillard, Ron

    1992-01-01

    The Einstein slew survey consists of 819 bright X-ray sources, of which 636 (or 78 percent) are identified with counterparts in standard catalogs. The importance of bright X-ray surveys is stressed, and the slew survey is compared to the Rosat all sky survey. Statistical techniques for minimizing confusion in arcminute error circles in digitized data are discussed. The 238 slew survey active galactic nuclei, clusters, and BL Lacertae objects identified to date and their implications for logN-logS and source evolution studies are described.

  17. PLMItRNA, a database for higher plant mitochondrial tRNAs and tRNA genes.

    PubMed Central

    Ceci, L R; Volpicella, M; Liuni, S; Volpetti, V; Licciulli, F; Gallerani, R

    1999-01-01

    The PLMItRNA database contains information and multialignments of tRNA genes and molecules detected in higher plant mitochondria. It has been developed from a previous compilation of higher plant mitochondrial tRNA genes [Sagliano,A., Volpicella,M., Gallerani,R. and Ceci,L.R. (1998) Nucleic Acids Res., 26, 154-155] and implemented with data and sequences of tRNA molecules retrieved from the literature. The current version of the database reports information on 171 genes and 16 tRNA molecules from 24 plants. PLMItRNA is accessible via WWW at http://bio-www.ba.cnr.it:8000/srs/ PMID:9847164

  18. Early herbivore alert matters: plant-mediated effects of egg deposition on higher trophic levels benefit plant fitness.

    PubMed

    Pashalidou, Foteini G; Frago, Enric; Griese, Eddie; Poelman, Erik H; van Loon, Joop J A; Dicke, Marcel; Fatouros, Nina E

    2015-09-01

    Induction of plant defences, specifically in response to herbivore attack, can save costs that would otherwise be needed to maintain defences even in the absence of herbivores. However, plants may suffer considerable damage during the time required to mount these defences against an attacker. This could be resolved if plants could respond to early cues, such as egg deposition, that reliably indicate future herbivory. We tested this hypothesis in a field experiment and found that egg deposition by the butterfly Pieris brassicae on black mustard (Brassica nigra) induced a plant response that negatively affected feeding caterpillars. The effect cascaded up to the third and fourth trophic levels (larval parasitoids and hyperparasitoids) by affecting the parasitisation rate and parasitoid performance. Overall, the defences induced by egg deposition had a positive effect on plant seed production and may therefore play an important role in the evolution of plant resistance to herbivores. PMID:26147078

  19. Contribution of PsbS Function and Stomatal Conductance to Foliar Temperature in Higher Plants

    PubMed Central

    Kulasek, Milena; Bernacki, Maciej Jerzy; Ciszak, Kamil; Witoń, Damian; Karpiński, Stanisław

    2016-01-01

    Natural capacity has evolved in higher plants to absorb and harness excessive light energy. In basic models, the majority of absorbed photon energy is radiated back as fluorescence and heat. For years the proton sensor protein PsbS was considered to play a critical role in non-photochemical quenching (NPQ) of light absorbed by PSII antennae and in its dissipation as heat. However, the significance of PsbS in regulating heat emission from a whole leaf has never been verified before by direct measurement of foliar temperature under changing light intensity. To test its validity, we here investigated the foliar temperature changes on increasing and decreasing light intensity conditions (foliar temperature dynamics) using a high resolution thermal camera and a powerful adjustable light-emitting diode (LED) light source. First, we showed that light-dependent foliar temperature dynamics is correlated with Chl content in leaves of various plant species. Secondly, we compared the foliar temperature dynamics in Arabidopsis thaliana wild type, the PsbS null mutant npq4-1 and a PsbS-overexpressing transgenic line under different transpiration conditions with or without a photosynthesis inhibitor. We found no direct correlations between the NPQ level and the foliar temperature dynamics. Rather, differences in foliar temperature dynamics are primarily affected by stomatal aperture, and rapid foliar temperature increase during irradiation depends on the water status of the leaf. We conclude that PsbS is not directly involved in regulation of foliar temperature dynamics during excessive light energy episodes. PMID:27273581

  20. Agricultural Application of Higher Plants for Their Antimicrobial Potentials in China

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This chapter describes published research into Chinese medicinal and aromatic plants as sources of new crop protectants. Literature was reviewed based on our personal experience, reported antimicrobial activity against plant pathogens, novel chemical structures, and potential for agricultural utiliz...

  1. Relative in vitro growth rates of duckweeds (Lemnaceae) - the most rapidly growing higher plants.

    PubMed

    Ziegler, P; Adelmann, K; Zimmer, S; Schmidt, C; Appenroth, K-J

    2015-01-01

    Relative growth rates (RGR), doubling times (DT) and relative weekly yields (RY) of 39 clones (ecotypes) from 13 species representing all five genera of duckweeds were determined under standardised cultivation conditions. RGR ranged overall from 0.153 to 0.519 day(-1) , DT from 1.34 to 4.54 days and RY from 2.9 to 37.8 week(-1) . The RGR and RY data can be compared directly to other published findings to only a limited extent on account of missing clonal designations for and limited accessibility to previously investigated clones, as well as the use of different data denominators. However, they are consistent with the published results of other comparative duckweed studies of similar scope in showing that RGR does not vary primarily at the level of the genus or species, but rather reflects the adaptation of individual clones to specific local conditions. The RGR data support the widely held assumption that duckweeds can grow faster than other higher plants and that they can thus surpass land-based agricultural crops in productivity. Duckweeds are highly promising for the production of biomass for nutrition and energy, but extensive clonal comparison will be required to identify the most suitable isolates for this purpose. PMID:24803032

  2. Photosynthetic complex stoichiometry dynamics in higher plants: environmental acclimation and photosynthetic flux control

    PubMed Central

    Schöttler, Mark A.; Tóth, Szilvia Z.

    2014-01-01

    The composition of the photosynthetic apparatus of higher plants is dynamically adjusted to long-term changes in environmental conditions such as growth light intensity and light quality, and to changing metabolic demands for ATP and NADPH imposed by stresses and leaf aging. By changing photosynthetic complex stoichiometry, a long-term imbalance between the photosynthetic production of ATP and NADPH and their metabolic consumption is avoided, and cytotoxic side reactions are minimized. Otherwise, an excess capacity of the light reactions, relative to the demands of primary metabolism, could result in a disturbance of cellular redox homeostasis and an increased production of reactive oxygen species, leading to the destruction of the photosynthetic apparatus and the initiation of cell death programs. In this review, changes of the abundances of the different constituents of the photosynthetic apparatus in response to environmental conditions and during leaf ontogenesis are summarized. The contributions of the different photosynthetic complexes to photosynthetic flux control and the regulation of electron transport are discussed. PMID:24860580

  3. Jordan, an active Volvox transposable element similar to higher plant transposons.

    PubMed Central

    Miller, S M; Schmitt, R; Kirk, D L

    1993-01-01

    We have isolated a 1595-bp transposable element from the multicellular green alga Volvox carteri following its insertion into the nitrate reductase (nitA) locus. This element, which we have named Jordan, has short (12-bp) terminal inverted repeats and creates a 3-bp target site duplication, like some higher plant transposons of the classic type. Contained within the first 200 bp of one end of the element are 55-bp inverted repeats, one of which begins with the terminal inverted repeat. Revertants of the transposon insertion into the nitA locus were obtained at a rate of approximately 10(-4) per Volvox embryo per generation. In each revertant examined, all transposon sequences were completely excised, but footprints containing both sets of duplicated bases, in addition to three to nine extra bases, were left behind. Jordan contains no significant open reading frames and so appears to be nonautonomous. DNA gel blot analysis indicates that Jordan is a member of a large family of homologous elements in the Volvox genome. We have isolated and characterized several of these homologs and found that they contain terminal very similar to those of Jordan. Efforts to utilize Jordan and its homologs as tools to tag and clone developmentally interesting genes of Volvox are discussed. PMID:8400878

  4. The uncommitted male and his female counterpart.

    PubMed

    Grand, H T

    1982-01-01

    In consonance with the new sexual freedom of our time, a distinct personality type has come to my attention in my clinical work: the uncommitted man and woman. Such a man and his female counterpart compulsively reenact the destructive, disappointing, infantile mother fixation, as well as the oedipal struggle, through a series of sexual relationships. Both men and women of this type fearfully avoid the sadomasochistic marriage model of the long-suffering depressive mother and the beleaguered father. Narcissistic wounds result from being used as narcissistic adjuncts by their parents, only to be dropped erratically or upon the birth of the next sibling. Consequences of the pathological separation-individuation process are feelings of abandonment, depression, and low self-esteem. Object constancy is interfered with by the stranglehold of the strong ambivalence. PMID:7165049

  5. Production characteristics of the "higher plants-soil-like substrate" system as an element of the bioregenerative life support system

    NASA Astrophysics Data System (ADS)

    Velichko, V. V.; Tikhomirov, A. A.; Ushakova, S. A.; Tikhomirova, N. A.; Shihov, V. N.; Tirranen, L. S.; Gribovskaya, I. A.

    2013-01-01

    The study addresses the possibility of long-duration operation of a higher plant conveyor, using a soil-like substrate (SLS) as the root zone. Chufa (Cyperus esculentus L.), radish (Raphanus sativus L.), and lettuce (Lactuca sativa L.) were used as study material. A chufa community consisting of 4 age groups and radish and lettuce communities consisting of 2 age groups were irrigated with a nutrient solution, which contained mineral elements extracted from the SLS. After each harvest, inedible biomass of the harvested plants and inedible biomasses of wheat and saltwort were added to the SLS. The amounts of the inedible biomasses of wheat and saltwort to be added to the SLS were determined based on the nitrogen content of the edible mass of harvested plants. CO2 concentration in the growth chamber was maintained within the range of 1100-1700 ppm. The results of the study show that higher plants can be grown quite successfully using the proposed process of plant waste utilization in the SLS. The addition of chufa inedible biomass to the SLS resulted in species-specific inhibition of growth of both cultivated crops and microorganisms in the "higher plants - SLS" system. There were certain differences between the amounts of some mineral elements removed from the SLS with the harvested edible biomass and those added to it with the inedible biomasses of wheat and saltwort.

  6. Research on the effects of altered gravity and other factors on the growth and development of higher plants

    NASA Technical Reports Server (NTRS)

    Brown, A. H.

    1973-01-01

    The establishment, maintenance and use of the NASA-UCSC Botanical Centrifuge is discussed. The broad goals of this project were: (1) to establish facilities for conducting experiments under conditions of sustained centrifugation; (2) to pursue research on the gravitational physiology of higher plants; (3) to develop experimental hardware suitable for studies of plant development in the weightless condition; and (4) to accommodate visiting investigators whose researches are of interest to the NASA Biomedical Program and who may require for some limited time, the use of a medium size centrifuge with associated facilities appropriate for plant physiological studies.

  7. Processes for producing polyhydroxybutyrate and related polyhydroxyalkanoates in the plastids of higher plants

    DOEpatents

    Somerville, Christopher R.; Nawrath, Christiane; Poirier, Yves

    1997-03-11

    The present invention relates to a process for producing poly-D-(-)-3-hydroxybutyric acid (PHB) and related polyhydroxyalkanoates (PHA) in the plastids of plants. The production of PHB is accomplished by genetically transforming plants with modified genes from microorganisms. The genes encode the enzymes required to synthesize PHB from acetyl-CoA or related metabolites and are fused with additional plant sequences for targeting the enzymes to the plastid.

  8. Processes for producing polyhydroxybutyrate and related polyhydroxyalkanoates in the plastids of higher plants

    DOEpatents

    Somerville, C.R.; Nawrath, C.; Poirier, Y.

    1997-03-11

    The present invention relates to a process for producing poly-D-(-)-3-hydroxybutyric acid (PHB) and related polyhydroxyalkanoates (PHA) in the plastids of plants. The production of PHB is accomplished by genetically transforming plants with modified genes from microorganisms. The genes encode the enzymes required to synthesize PHB from acetyl-CoA or related metabolites and are fused with additional plant sequences for targeting the enzymes to the plastid. 37 figs.

  9. Different hydrogen isotope fractionations during lipid formation in higher plants: Implications for paleohydrology reconstruction at a global scale.

    PubMed

    Liu, Jinzhao; Liu, Weiguo; An, Zhisheng; Yang, Hong

    2016-01-01

    Leaf wax δDn-alkane values have shown to differ significantly among plant life forms (e.g., among grasses, shrubs, and trees) in higher plants. However, the underlying causes for the differences in leaf wax δDn-alkane values among different plant life forms remain poorly understood. In this study, we observed that leaf wax δDn-alkane values between major high plant lineages (eudicots versus monocots) differed significantly under the same environmental conditions. Such a difference primarily inherited from different hydrogen biosynthetic fractionations (εwax-lw). Based upon a reanalysis of the available leaf wax δDn-alkane dataset from modern plants in the Northern Hemisphere, we discovered that the apparent hydrogen fractionation factor (εwax-p) between leaf wax δDn-alkane values of major angiosperm lineages and precipitation δD values exhibited distinguishable distribution patterns at a global scale, with an average of -140‰ for monocotyledonous species, -107‰ for dicotyledonous species. Additionally, variations of leaf wax δDn-alkane values and the εwax-p values in gymnosperms are similar to those of dicotyledonous species. Therefore, the data let us believe that biological factors inherited from plant taxonomies have a significant effect on controlling leaf wax δDn-alkane values in higher plants. PMID:26806719

  10. Different hydrogen isotope fractionations during lipid formation in higher plants: Implications for paleohydrology reconstruction at a global scale

    PubMed Central

    Liu, Jinzhao; Liu, Weiguo; An, Zhisheng; Yang, Hong

    2016-01-01

    Leaf wax δDn-alkane values have shown to differ significantly among plant life forms (e.g., among grasses, shrubs, and trees) in higher plants. However, the underlying causes for the differences in leaf wax δDn-alkane values among different plant life forms remain poorly understood. In this study, we observed that leaf wax δDn-alkane values between major high plant lineages (eudicots versus monocots) differed significantly under the same environmental conditions. Such a difference primarily inherited from different hydrogen biosynthetic fractionations (εwax-lw). Based upon a reanalysis of the available leaf wax δDn-alkane dataset from modern plants in the Northern Hemisphere, we discovered that the apparent hydrogen fractionation factor (εwax-p) between leaf wax δDn-alkane values of major angiosperm lineages and precipitation δD values exhibited distinguishable distribution patterns at a global scale, with an average of −140‰ for monocotyledonous species, −107‰ for dicotyledonous species. Additionally, variations of leaf wax δDn-alkane values and the εwax-p values in gymnosperms are similar to those of dicotyledonous species. Therefore, the data let us believe that biological factors inherited from plant taxonomies have a significant effect on controlling leaf wax δDn-alkane values in higher plants. PMID:26806719

  11. Different hydrogen isotope fractionations during lipid formation in higher plants: Implications for paleohydrology reconstruction at a global scale

    NASA Astrophysics Data System (ADS)

    Liu, Jinzhao; Liu, Weiguo; An, Zhisheng; Yang, Hong

    2016-01-01

    Leaf wax δDn-alkane values have shown to differ significantly among plant life forms (e.g., among grasses, shrubs, and trees) in higher plants. However, the underlying causes for the differences in leaf wax δDn-alkane values among different plant life forms remain poorly understood. In this study, we observed that leaf wax δDn-alkane values between major high plant lineages (eudicots versus monocots) differed significantly under the same environmental conditions. Such a difference primarily inherited from different hydrogen biosynthetic fractionations (ɛwax-lw). Based upon a reanalysis of the available leaf wax δDn-alkane dataset from modern plants in the Northern Hemisphere, we discovered that the apparent hydrogen fractionation factor (ɛwax-p) between leaf wax δDn-alkane values of major angiosperm lineages and precipitation δD values exhibited distinguishable distribution patterns at a global scale, with an average of -140‰ for monocotyledonous species, -107‰ for dicotyledonous species. Additionally, variations of leaf wax δDn-alkane values and the ɛwax-p values in gymnosperms are similar to those of dicotyledonous species. Therefore, the data let us believe that biological factors inherited from plant taxonomies have a significant effect on controlling leaf wax δDn-alkane values in higher plants.

  12. Retrofitting the Williams Energy Services Ignacio Plant for higher throughput and recovery

    SciTech Connect

    Lynch, J.T.; Pitman, R.N.

    1999-07-01

    The Ignacio Plant located near Durango, Colorado was originally designed to process 346 MMscfd of feed gas and to recover approximately 82% of the contained ethane. Based on increasing volumes of available feed gas, Williams Energy Services (WES) undertook a study to investigate alternatives for increasing plant capacity and ethane recovery. This study led to the selection of Ortloff's Recycle Split-Vapor (RSV) process for retrofitting the existing facility because it offered several very important advantages: maximum utilization of existing equipment, a 30% increase in plant feed handling capacity and an increase in average ethane recovery to 94% without adding residue compressors. This paper presents the comparative case analysis that led to the selection of the RSV design. It also describes the modifications required for the retrofit, all of which can be accomplished with minimum plant down time. The modified Ignacio Plant is scheduled for startup in March 1999.

  13. Mitochondrial phosphatidylserine decarboxylase from higher plants. Functional complementation in yeast, localization in plants, and overexpression in Arabidopsis.

    PubMed

    Rontein, Denis; Wu, Wen-I; Voelker, Dennis R; Hanson, Andrew D

    2003-07-01

    Plants are known to synthesize ethanolamine (Etn) moieties by decarboxylation of free serine (Ser), but there is also some evidence for phosphatidyl-Ser (Ptd-Ser) decarboxylation. Database searches identified diverse plant cDNAs and an Arabidopsis gene encoding 50-kD proteins homologous to yeast (Saccharomyces cerevisiae) and mammalian mitochondrial Ptd-Ser decarboxylases (PSDs). Like the latter, the plant proteins have putative mitochondrial targeting and inner membrane sorting sequences and contain near the C terminus a Glycine-Serine-Threonine motif corresponding to the site of proteolysis and catalytic pyruvoyl residue formation. A truncated tomato (Lycopersicon esculentum) cDNA lacking the targeting sequence and a chimeric construct in which the targeting and sorting sequences were replaced by those from yeast PSD1 both complemented the Etn requirement of a yeast psd1 psd2 mutant, and PSD activity was detected in the mitochondria of the complemented cells. Immunoblot analysis of potato (Solanum tuberosum) mitochondria demonstrated that PSD is located in mitochondrial membranes, and mRNA analysis in Arabidopsis showed that the mitochondrial PSD gene is expressed at low levels throughout the plant. An Arabidopsis knockup mutant grew normally but had 6- to 13-fold more mitochondrial PSD mRNA and 9-fold more mitochondrial PSD activity. Total membrane PSD activity was, however, unchanged in the mutant, showing mitochondrial activity to be a minor part of the total. These results establish that plants can synthesize Etn moieties via a phospholipid pathway and have both mitochondrial and extramitochondrial PSDs. They also indicate that mitochondrial PSD is an important housekeeping enzyme whose expression is strongly regulated at the transcriptional level. PMID:12857846

  14. Mitochondrial Phosphatidylserine Decarboxylase from Higher Plants. Functional Complementation in Yeast, Localization in Plants, and Overexpression in Arabidopsis1

    PubMed Central

    Rontein, Denis; Wu, Wen-I; Voelker, Dennis R.; Hanson, Andrew D.

    2003-01-01

    Plants are known to synthesize ethanolamine (Etn) moieties by decarboxylation of free serine (Ser), but there is also some evidence for phosphatidyl-Ser (Ptd-Ser) decarboxylation. Database searches identified diverse plant cDNAs and an Arabidopsis gene encoding 50-kD proteins homologous to yeast (Saccharomyces cerevisiae) and mammalian mitochondrial Ptd-Ser decarboxylases (PSDs). Like the latter, the plant proteins have putative mitochondrial targeting and inner membrane sorting sequences and contain near the C terminus a Glycine-Serine-Threonine motif corresponding to the site of proteolysis and catalytic pyruvoyl residue formation. A truncated tomato (Lycopersicon esculentum) cDNA lacking the targeting sequence and a chimeric construct in which the targeting and sorting sequences were replaced by those from yeast PSD1 both complemented the Etn requirement of a yeast psd1 psd2 mutant, and PSD activity was detected in the mitochondria of the complemented cells. Immunoblot analysis of potato (Solanum tuberosum) mitochondria demonstrated that PSD is located in mitochondrial membranes, and mRNA analysis in Arabidopsis showed that the mitochondrial PSD gene is expressed at low levels throughout the plant. An Arabidopsis knockup mutant grew normally but had 6- to 13-fold more mitochondrial PSD mRNA and 9-fold more mitochondrial PSD activity. Total membrane PSD activity was, however, unchanged in the mutant, showing mitochondrial activity to be a minor part of the total. These results establish that plants can synthesize Etn moieties via a phospholipid pathway and have both mitochondrial and extramitochondrial PSDs. They also indicate that mitochondrial PSD is an important housekeeping enzyme whose expression is strongly regulated at the transcriptional level. PMID:12857846

  15. Interactions of metal-based engineered nanoparticles with aquatic higher plants: A review of the state of current knowledge.

    PubMed

    Thwala, Melusi; Klaine, Stephen J; Musee, Ndeke

    2016-07-01

    The rising potential for the release of engineered nanoparticles (ENPs) into aquatic environments requires evaluation of risks to protect ecological health. The present review examines knowledge pertaining to the interactions of metal-based ENPs with aquatic higher plants, identifies information gaps, and raises considerations for future research to advance knowledge on the subject. The discussion focuses on ENPs' bioaccessibility; uptake, adsorption, translocation, and bioaccumulation; and toxicity effects on aquatic higher plants. An information deficit surrounds the uptake of ENPs and associated dynamics, because the influence of ENP characteristics and water quality conditions has not been well documented. Dissolution appears to be a key mechanism driving bioaccumulation of ENPs, whereas nanoparticulates often adsorb to plant surfaces with minimal internalization. However, few reports document the internalization of ENPs by plants; thus, the role of nanoparticulates' internalization in bioaccumulation and toxicity remains unclear, requiring further investigation. The toxicities of metal-based ENPs mainly have been associated with dissolution as a predominant mechanism, although nano toxicity has also been reported. To advance knowledge in this domain, future investigations need to integrate the influence of ENP characteristics and water physicochemical parameters, as their interplay determines ENP bioaccessibility and influences their risk to health of aquatic higher plants. Furthermore, harmonization of test protocols is recommended for fast tracking the generation of comparable data. Environ Toxicol Chem 2016;35:1677-1694. © 2016 SETAC. PMID:26757140

  16. Small intestinal hydrolysis of plant glucosides: higher glucohydrolase activities in rodents than passerine birds.

    PubMed

    Lessner, Krista M; Dearing, M Denise; Izhaki, Ido; Samuni-Blank, Michal; Arad, Zeev; Karasov, William H

    2015-09-01

    Glycosides are a major group of plant secondary compounds characterized by one or more sugars conjugated to a lipophilic, possibly toxic aglycone, which is released upon hydrolysis. We compared small intestinal homogenate hydrolysis activity of three rodent and two avian species against four substrates: amygdalin and sinigrin, two plant-derived glucosides, the sugar lactose, whose hydrolysis models some activity against flavonoid and isoflavonoid glucosides, and the disaccharide sugar maltose (from starch), used as a comparator. Three new findings extend our understanding of physiological processing of plant glucosides: (1) the capacity of passerine birds to hydrolyze plant glucosides seems relatively low, compared with rodents; (2) in this first test of vertebrates' enzymic capacity to hydrolyze glucosinolates, sinigrin hydrolytic capacity seems low; (3) in laboratory mice, hydrolytic activity against lactose resides on the enterocytes' apical membrane facing the intestinal lumen, but activity against amygdalin seems to reside inside enterocytes. PMID:26113142

  17. Gene-enzyme telationships in somatic cells and their organismal derivatives in higher plants. Progress report

    SciTech Connect

    Jensen, R. A.

    1980-04-21

    Progress is reported in the following subject areas: (1) chemistry of the arogenate molecule; (2) plant enzymology at the organismal level; (3) isolation of regulatory mutants in tobacco; and (4) stability of the haploid state in Nicotiana sylvestris.

  18. Molecular Properties and Functional Divergence of the Dehydroascorbate Reductase Gene Family in Lower and Higher Plants

    PubMed Central

    Zhang, Yuan-Jie; Wang, Wei; Yang, Hai-Ling; Li, Yue; Kang, Xiang-Yang; Wang, Xiao-Ru; Yang, Zhi-Ling

    2015-01-01

    Dehydroascorbate reductase (DHAR), which reduces oxidized ascorbate, is important for maintaining an appropriate ascorbate redox state in plant cells. To date, genome-wide molecular characterization of DHARs has only been conducted in bryophytes (Physcomitrella patens) and eudicots (e.g. Arabidopsis thaliana). In this study, to gain a general understanding of the molecular properties and functional divergence of the DHARs in land plants, we further conducted a comprehensive analysis of DHARs from the lycophyte Selaginella moellendorffii, gymnosperm Picea abies and monocot Zea mays. DHARs were present as a small gene family in all of the land plants we examined, with gene numbers ranging from two to four. All the plants contained cytosolic and chloroplastic DHARs, indicating dehydroascorbate (DHA) can be directly reduced in the cytoplasm and chloroplast by DHARs in all the plants. A novel vacuolar DHAR was found in Z. mays, indicating DHA may also be reduced in the vacuole by DHARs in Z. mays. The DHARs within each species showed extensive functional divergence in their gene structures, subcellular localizations, and enzymatic characteristics. This study provides new insights into the molecular characteristics and functional divergence of DHARs in land plants. PMID:26684301

  19. Molecular Properties and Functional Divergence of the Dehydroascorbate Reductase Gene Family in Lower and Higher Plants.

    PubMed

    Zhang, Yuan-Jie; Wang, Wei; Yang, Hai-Ling; Li, Yue; Kang, Xiang-Yang; Wang, Xiao-Ru; Yang, Zhi-Ling

    2015-01-01

    Dehydroascorbate reductase (DHAR), which reduces oxidized ascorbate, is important for maintaining an appropriate ascorbate redox state in plant cells. To date, genome-wide molecular characterization of DHARs has only been conducted in bryophytes (Physcomitrella patens) and eudicots (e.g. Arabidopsis thaliana). In this study, to gain a general understanding of the molecular properties and functional divergence of the DHARs in land plants, we further conducted a comprehensive analysis of DHARs from the lycophyte Selaginella moellendorffii, gymnosperm Picea abies and monocot Zea mays. DHARs were present as a small gene family in all of the land plants we examined, with gene numbers ranging from two to four. All the plants contained cytosolic and chloroplastic DHARs, indicating dehydroascorbate (DHA) can be directly reduced in the cytoplasm and chloroplast by DHARs in all the plants. A novel vacuolar DHAR was found in Z. mays, indicating DHA may also be reduced in the vacuole by DHARs in Z. mays. The DHARs within each species showed extensive functional divergence in their gene structures, subcellular localizations, and enzymatic characteristics. This study provides new insights into the molecular characteristics and functional divergence of DHARs in land plants. PMID:26684301

  20. Bioremediation of Atmospheric Hydrocarbons via Bacteria Naturally Associated with Leaves of Higher Plants.

    PubMed

    Ali, N; Al-Awadhi, H; Dashti, N; Khanafer, M; El-Nemr, I; Sorkhoh, N; Radwan, S S

    2015-01-01

    Bacteria associated with leaves of sixteen cultivated and wild plant species from all over Kuwait were analyzed by a culture-independent approach. This technique depended on partial sequencing of 16S rDNA regions in total genomic DNA from the bacterial consortia and comparing the resulting sequences with those in the GenBank database. To release bacterial cells from leaves, tough methods such as sonication co-released too much leaf chloroplasts whose DNA interfered with the bacterial DNA. A more satisfactory bacterial release with a minimum of chloroplast co-release was done by gently rubbing the leaf surfaces with soft tooth brushes in phosphate buffer. The leaves of all plant species harbored on their surfaces bacterial communities predominated by hydrocarbonoclastic (hydrocarbon-utilizing) bacterial genera. Leaves of 6 representative plants brought about in the laboratory effective removal of volatile hydrocarbons in sealed microcosms. Each individual plant species had a unique bacterial community structure. Collectively, the phyllospheric microflora on the studied plants comprised the genera Flavobacterium, Halomonas, Arthrobacter, Marinobacter, Neisseria, Ralstonia, Ochrobactrum. Exiguobacterium, Planomicrobium, Propionibacterium, Kocuria, Rhodococcus and Stenotrophomonas. This community structure was dramatically different from the structure we determined earlier for the same plants using the culture-dependent approach, although in both cases, hydrocarbonoclastic bacteria were frequent. PMID:25946637

  1. The soil-like substrate: problems and perspective of its use for higher plants cultivation in LSS

    NASA Astrophysics Data System (ADS)

    Tikhomirov, Alexander A.; Velichko, Vladimir; Nickolay Manukovsky, D..; Ushakova, Sofya; Kovalev, Vladimir

    Being the product of biological mineralization of plant wastes, the soil-like substrate (SLS) contains sufficient amount of nutrients required for plant growth and development. The multiple experiments carried out at the IBP SB RAS demonstrated the SLS fitness for cultivation of higher plant of phototrophic unit in biological-technical life support systems (BTLSS). Together with it, some problems demanding further investigations and solutions had revealed. One of the cardinal problems was interlinked with a relatively low allowance of assimilable nitrogen in comparison with other elements contained in the SLS. Different problems arising under a durational plant cultivation on the SLS in a regime of multi-species uneven-aged conveyer is considered. The work attends considerable attention to analysis of questions occurring at plant cultivation on a reusable SLS that resulted in a yield decrease. The ways of more effective exploitation of the SLS both as a bioreactor for plant wastes mineralization and as a substrate for plant cultivation in a long-functioning BTLSS of an increased closure level of mass exchange processes are suggested.

  2. Production characteristics of lettuce Lactuca sativa L. in the frame of the first crop tests in the Higher Plant Chamber integrated into the MELiSSA Pilot Plant

    NASA Astrophysics Data System (ADS)

    Tikhomirova, Natalia; Lawson, Jamie; Stasiak, Michael; Dixon, Mike; Paille, Christel; Peiro, Enrique; Fossen, Arnaud; Godia, Francesc

    Micro-Ecological Life Support System Alternative (MELiSSA) is an artificial closed ecosystem that is considered a tool for the development of a bioregenerative life support system for manned space missions. One of the five compartments of MELiSSA loop -Higher Plant Chamber was recently integrated into the MELiSSA Pilot Plant facility at Universitat Aut`noma deo Barcelona. The main contributions expected by integration of this photosynthetic compartment are oxygen, water, vegetable food production and CO2 consumption. Production characteristics of Lactuca sativa L., as a MELiSSA candidate crop, were investigated in this work in the first crop experiments in the MELiSSA Pilot Plant facility. The plants were grown in batch culture and totaled 100 plants with a growing area 5 m long and 1 m wide in a sealed controlled environment. Several replicates of the experiments were carried out with varying duration. It was shown that after 46 days of lettuce cultivation dry edible biomass averaged 27, 2 g per plant. However accumulation of oxygen in the chamber, which required purging of the chamber, and decrease in the food value of the plants was observed. Reducing the duration of the tests allowed uninterrupted test without opening the system and also allowed estimation of the crop's carbon balance. Results of productivity, tissue composition, nutrient uptake and canopy photosynthesis of lettuce regardless of test duration are discussed in the paper.

  3. Molecular characterization of the spliceosomal proteins U1A and U2B" from higher plants.

    PubMed Central

    Simpson, G G; Clark, G P; Rothnie, H M; Boelens, W; van Venrooij, W; Brown, J W

    1995-01-01

    In addition to their role in pre-mRNA splicing, the human spliceosomal proteins U1A and U2B" are important models of how RNP motif-containing proteins execute sequence-specific RNA binding. Genes encoding U1A and U2B" have been isolated from potato and thereby provide the only evolutionary comparison available for both proteins and represent the only full-length genes encoding plant spliceosomal proteins to have been cloned and characterized. In vitro RNA binding experiments revealed the ability of potato U2B" to interact with human U2A' to enhance sequence-specific binding and to distinguish cognate RNAs of either plant or animal origin. A comparison of the sequence of U1A and U2B" proteins indicated that multiple residues which could affect RNP motif conformation probably govern the specific distinction in RNA binding by these proteins. Since human U1A modulates polyadenylation in vertebrates, the possibility that plant U1A might be exploited in the characterization of this process in plants was examined. However, unlike vertebrate U1A, neither U1A from potato nor Arabidopsis bound their own mRNA and no evidence for binding to upstream efficiency elements in polyadenylation signals was obtained, suggesting that plant U1A is not involved in polyadenylation. Images PMID:7556097

  4. [Cyclic Guanosine Monophosphate as a Mediator in Processes of Stress Signaling Transduction in Higher Plants].

    PubMed

    Dubovskaya, L V; Bakakina, Y S; Volotovski, I D

    2015-01-01

    Currently, biophysical mechanisms of stress signaling transduction became an object of consideration of researchers in connection with the urgent necessity to develop new techniques to enhance the sustainability and productivity of agricultural crops. The development of sensitive methods for the determination of cyclic guanosine monophosphate (cGMP) and comparative analysis of cGMP-dependent events in biological systems has contributed to progress in the understanding of the functioning of cGMP in plant cells. Currently, it is shown that cGMP as a secondary mediator is involved in such vital processes of growth and development of plants as seed germination, cell division, development of chloroplasts, flowering and regulation of stomatal movements. This review summarizes the available data in the literature about the role of cGMP in the responses of plant organisms to the action of stress factors of abiotic and biotic nature and its interaction with other intracellular mediators. With the use of existing ideas about the biophysical mechanisms of stress in plants, the basic elements of cGMP-dependent signal transduction system in a plant cell are considered. PMID:26394467

  5. Can genetically based clines in plant defence explain greater herbivory at higher latitudes?

    PubMed

    Anstett, Daniel N; Ahern, Jeffrey R; Glinos, Julia; Nawar, Nabanita; Salminen, Juha-Pekka; Johnson, Marc T J

    2015-12-01

    Greater plant defence is predicted to evolve at lower latitudes in response to increased herbivore pressure. However, recent studies question the generality of this pattern. In this study, we tested for genetically based latitudinal clines in resistance to herbivores and underlying defence traits of Oenothera biennis. We grew plants from 137 populations from across the entire native range of O. biennis. Populations from lower latitudes showed greater resistance to multiple specialist and generalist herbivores. These patterns were associated with an increase in total phenolics at lower latitudes. A significant proportion of the phenolics were driven by the concentrations of two major ellagitannins, which exhibited opposing latitudinal clines. Our analyses suggest that these findings are unlikely to be explained by local adaptation of herbivore populations or genetic variation in phenology. Rather greater herbivory at high latitudes can be explained by latitudinal clines in the evolution of plant defences. PMID:26482702

  6. Differentiating moss from higher plants is critical in studying the carbon cycle of the boreal biome.

    PubMed

    Yuan, Wenping; Liu, Shuguang; Dong, Wenjie; Liang, Shunlin; Zhao, Shuqing; Chen, Jingming; Xu, Wenfang; Li, Xianglan; Barr, Alan; Andrew Black, T; Yan, Wende; Goulden, Mike L; Kulmala, Liisa; Lindroth, Anders; Margolis, Hank A; Matsuura, Yojiro; Moors, Eddy; van der Molen, Michiel; Ohta, Takeshi; Pilegaard, Kim; Varlagin, Andrej; Vesala, Timo

    2014-01-01

    The satellite-derived normalized difference vegetation index (NDVI), which is used for estimating gross primary production (GPP), often includes contributions from both mosses and vascular plants in boreal ecosystems. For the same NDVI, moss can generate only about one-third of the GPP that vascular plants can because of its much lower photosynthetic capacity. Here, based on eddy covariance measurements, we show that the difference in photosynthetic capacity between these two plant functional types has never been explicitly included when estimating regional GPP in the boreal region, resulting in a substantial overestimation. The magnitude of this overestimation could have important implications regarding a change from a current carbon sink to a carbon source in the boreal region. Moss abundance, associated with ecosystem disturbances, needs to be mapped and incorporated into GPP estimates in order to adequately assess the role of the boreal region in the global carbon cycle. PMID:24967601

  7. Conservation and diversity of gene families explored using the CODEHOP strategy in higher plants

    PubMed Central

    Morant, Marc; Hehn, Alain; Werck-Reichhart, Danièle

    2002-01-01

    Background Availability of genomewide information on an increasing but still limited number of plants offers the possibility of identifying orthologues, or related genes, in species with major economical impact and complex genomes. In this paper we exploit the recently described CODEHOP primer design and PCR strategy for targeted isolation of homologues in large gene families. Results The method was tested with two different objectives. The first was to analyze the evolution of the CYP98 family of cytochrome P450 genes involved in 3-hydroxylation of phenolic compounds and lignification in a broad range of plant species. The second was to isolate an orthologue of the sorghum glucosyl transferase UGT85B1 and to determine the complexity of the UGT85 family in wheat. P450s of the CYP98 family or closely related sequences were found in all vascular plants. No related sequence was found in moss. Neither extensive duplication of the CYP98 genes nor an orthologue of UGT85B1 were found in wheat. The UGT85A subfamily was however found to be highly variable in wheat. Conclusions Our data are in agreement with the implication of CYP98s in lignification and the evolution of 3-hydroxylation of lignin precursors with vascular plants. High conservation of the CYP98 family strongly argues in favour of an essential function in plant development. Conversely, high duplication and diversification of the UGT85A gene family in wheat suggests its involvement in adaptative response and provides a valuable pool of genes for biotechnological applications. This work demonstrates the high potential of the CODEHOP strategy for the exploration of large gene families in plants. PMID:12153706

  8. Congruence and Diversity of Butterfly-Host Plant Associations at Higher Taxonomic Levels

    PubMed Central

    Ferrer-Paris, José R.; Sánchez-Mercado, Ada; Viloria, Ángel L.; Donaldson, John

    2013-01-01

    We aggregated data on butterfly-host plant associations from existing sources in order to address the following questions: (1) is there a general correlation between host diversity and butterfly species richness?, (2) has the evolution of host plant use followed consistent patterns across butterfly lineages?, (3) what is the common ancestral host plant for all butterfly lineages? The compilation included 44,148 records from 5,152 butterfly species (28.6% of worldwide species of Papilionoidea) and 1,193 genera (66.3%). The overwhelming majority of butterflies use angiosperms as host plants. Fabales is used by most species (1,007 spp.) from all seven butterfly families and most subfamilies, Poales is the second most frequently used order, but is mostly restricted to two species-rich subfamilies: Hesperiinae (56.5% of all Hesperiidae), and Satyrinae (42.6% of all Nymphalidae). We found a significant and strong correlation between host plant diversity and butterfly species richness. A global test for congruence (Parafit test) was sensitive to uncertainty in the butterfly cladogram, and suggests a mixed system with congruent associations between Papilionidae and magnoliids, Hesperiidae and monocots, and the remaining subfamilies with the eudicots (fabids and malvids), but also numerous random associations. The congruent associations are also recovered as the most probable ancestral states in each node using maximum likelihood methods. The shift from basal groups to eudicots appears to be more likely than the other way around, with the only exception being a Satyrine-clade within the Nymphalidae that feed on monocots. Our analysis contributes to the visualization of the complex pattern of interactions at superfamily level and provides a context to discuss the timing of changes in host plant utilization that might have promoted diversification in some butterfly lineages. PMID:23717448

  9. Antimicrobial agents from higher plants. The quaternary alkaloids of Ptelea trifoliata.

    PubMed

    Mitscher, L A; Bathala, M S; Clark, G W; Beal, J L

    1975-01-01

    Quaternary alkaloid extracts of Ptelea trifoliata showed potentially interesting antimicrobial activity. Chromatographic examination showed the presence of six components. Of these, choline and O-4-methyl ptelefolinium were known compounds. Rational structures are proposed for the new alkaloids, O-4-methylhydroxyluninium, neohydroxylunine and pteleatinium salts. Pteleatinium salt is responsible for the antimicrobial activity of the extracts of the plant. PMID:1094214

  10. Molecular characterization of a FKBP-type immunophilin from higher plants.

    PubMed

    Luan, S; Kudla, J; Gruissem, W; Schreiber, S L

    1996-07-01

    Immunophilins are intracellular receptors for the immunosuppressants cyclosporin A, FK506, and rapamycin. In addition to their use in organ transplantation, these natural products have been used to investigate signaling pathways in yeast, plant, and mammalian cells. We have recently described the identification of an immunosuppressant-sensitive signaling pathway in and the purification of several immunophilins from Vicia faba plants. We now report the molecular characterization of a 15 kDa FK506- and rapamycin-binding protein from V. faba (VfFKBP15). The amino acid sequence deduced from the cDNA starts with a signal peptide of 22 hydrophobic amino acids. The core region of VfFKBP15 is most similar to yeast and mammalian FKBP13 localized in the endoplasmic reticulum (ER). In addition, VfFKBP15 has a carboxyl-terminal sequence that is ended with SSEL, a putative ER retention signal. These findings suggest that VfFKBP15 is a functional homolog of FKBP13 from other organisms. Interestingly, two distinct cDNAs corresponding to two isoforms of FKBP15 have been cloned from Arabidopsis and also identified from rice data base, suggesting that pFKBP15 (plant FKBP15) is encoded by a small gene family in plants. This adds to the diversity of plant FKBP members even with the same subcellular localization and is in contrast with the situation in mammalian and yeast systems in which only one FKBP13 gene has been found. Like the mammalian and yeast FKBP13, the recombinant VfFKBP15 protein has rotamase activity that is inhibited by both FK506 and rapamycin with a Ki value of 30 nM and 0.9 nM, respectively, illustrating that VfFKBP15 binds rapamycin in preference over FK506. The mRNA of VfFKBP15 is ubiquitously expressed in various plant tissues including leaves, stems, and roots, consistent with the ER localization of the protein. Levels of VfFKBP15 mRNA are elevated by heat shock, suggesting a possible role for this FKBP member under stress conditions. PMID:8692927

  11. Isolation and characterization of ice-binding proteins from higher plants.

    PubMed

    Middleton, Adam J; Vanderbeld, Barbara; Bredow, Melissa; Tomalty, Heather; Davies, Peter L; Walker, Virginia K

    2014-01-01

    The characterization of ice-binding proteins from plants can involve many techniques, only a few of which are presented here. Chief among these methods are tests for ice recrystallization inhibition activity. Two distinct procedures are described; neither is normally used for precise quantitative assays. Thermal hysteresis assays are used for quantitative studies but are also useful for ice crystal morphologies, which are important for the understanding of ice-plane binding. Once the sequence of interest is cloned, recombinant expression, necessary to verify ice-binding protein identity can present challenges, and a strategy for recovery of soluble, active protein is described. Lastly, verification of function in planta borrows from standard protocols, but with an additional screen applicable to ice-binding proteins. Here we have attempted to assist researchers wishing to isolate and characterize ice-binding proteins from plants with a few methods critical to success. PMID:24852641

  12. Proteomics of terpenoid biosynthesis and secretion in trichomes of higher plant species.

    PubMed

    Champagne, Antoine; Boutry, Marc

    2016-08-01

    Among the specialized (secondary) plant metabolites, terpenoids represent the most diverse family and are often involved in the defense against pathogens and herbivores. Terpenoids can be produced both constitutively and in response to the environment. At the front line of this defense strategy are the glandular trichomes, which are organs dedicated primarily to the production of specialized metabolites. Mass spectrometry-based proteomics is a powerful tool, which is very useful to investigate enzymes involved in metabolic pathways, such as the synthesis and secretion of terpenoids in glandular trichomes. Here we review the strategies used to investigate the specific roles of these particular organs from non-model plant species, mainly belonging to the Lamiaceae, Solanaceae, and Cannabaceae families. We discuss how proteomics helps to accurately pinpoint candidate proteins to be functionally characterized, and how technological progresses create opportunities for studying low-abundance proteins, such as the ones related to the synthesis and transport of specialized metabolites. This article is part of a Special Issue entitled: Plant Proteomics--a bridge between fundamental processes and crop production, edited by Dr. Hans-Peter Mock. PMID:26873244

  13. The PsbW protein stabilizes the supramolecular organization of photosystem II in higher plants.

    PubMed

    García-Cerdán, José G; Kovács, Laszlo; Tóth, Tünde; Kereïche, Sami; Aseeva, Elena; Boekema, Egbert J; Mamedov, Fikret; Funk, Christiane; Schröder, Wolfgang P

    2011-02-01

    PsbW, a 6.1-kDa low-molecular-weight protein, is exclusive to photosynthetic eukaryotes, and associates with the photosystem II (PSII) protein complex. In vivo and in vitro comparison of Arabidopsis thaliana wild-type plants with T-DNA insertion knock-out mutants completely lacking the PsbW protein, or with antisense inhibition plants exhibiting decreased levels of PsbW, demonstrated that the loss of PsbW destabilizes the supramolecular organization of PSII. No PSII-LHCII supercomplexes could be detected or isolated in the absence of the PsbW protein. These changes in macro-organization were accompanied by a minor decrease in the chlorophyll fluorescence parameter F(V) /F(M) , a strongly decreased PSII core protein phosphorylation and a modification of the redox state of the plastoquinone (PQ) pool in dark-adapted leaves. In addition, the absence of PsbW protein led to faster redox changes in the PQ pool, i.e. transitions from state 1 to state 2, as measured by changes in stationary fluorescence (F(S) ) kinetics, compared with the wild type. Despite these dramatic effects on macromolecular structure, the transgenic plants exhibited no significant phenotype under normal growth conditions. We suggest that the PsbW protein is located close to the minor antenna of the PSII complex, and is important for the contact and stability between several PSII-LHCII supercomplexes. PMID:21265891

  14. Role of Ca{sup ++}/calmodulin in the regulation of microtubules in higher plants. Progress report, FY 1992

    SciTech Connect

    Cyr, R.

    1992-12-31

    The cytoskeleton including its microtubule (Mt) component participates in processes that directly affect growth and development in higher plants. Normal cytoskeletal function requires the precise and orderly arrangement of Mts into several cell cycle and developmentally specific arrays. The cortical array somehow directs the deposition of cellulose. Little molecular information is available regarding the formation of these arrays or the cellular signals to which they respond. Experimental data described here suggests that plant cells use calcium, in the form of a Ca{sup ++}/calmodulin complex, to affect the dynamics of Mts within the cortical array. Owing to the importance of Ca{sup ++} as a regulatory ion in higher plants we are probing for a putative Ca{sup ++}/Mt transduction pathway which may serve to integrate Mt activities within the growing and developing plant cell. We are using a lysed cell model in conjunction with immunocytochemical and biochemical methodologies to dissect how Ca{sup ++}/calmodulin interacts with Mts to affect their function.

  15. Chloroplast division in higher plants requires members of two functionally divergent gene families with homology to bacterial ftsZ.

    PubMed Central

    Osteryoung, K W; Stokes, K D; Rutherford, S M; Percival, A L; Lee, W Y

    1998-01-01

    The division of plastids is critical for viability in photosynthetic eukaryotes, but the mechanisms associated with this process are still poorly understood. We previously identified a nuclear gene from Arabidopsis encoding a chloroplast-localized homolog of the bacterial cell division protein FtsZ, an essential cytoskeletal component of the prokaryotic cell division apparatus. Here, we report the identification of a second nuclear-encoded FtsZ-type protein from Arabidopsis that does not contain a chloroplast targeting sequence or other obvious sorting signals and is not imported into isolated chloroplasts, which strongly suggests that it is localized in the cytosol. We further demonstrate using antisense technology that inhibiting expression of either Arabidopsis FtsZ gene (AtFtsZ1-1 or AtFtsZ2-1) in transgenic plants reduces the number of chloroplasts in mature leaf cells from 100 to one, indicating that both genes are essential for division of higher plant chloroplasts but that each plays a distinct role in the process. Analysis of currently available plant FtsZ sequences further suggests that two functionally divergent FtsZ gene families encoding differentially localized products participate in chloroplast division. Our results provide evidence that both chloroplastic and cytosolic forms of FtsZ are involved in chloroplast division in higher plants and imply that important differences exist between chloroplasts and prokaryotes with regard to the roles played by FtsZ proteins in the division process. PMID:9836740

  16. Immunodetection of the Ferredoxin-NADP+ Oxidoreductase-Binding Protein Complex in Thylakoids of Different Higher Plant Species 1

    PubMed Central

    Soncini, Fernando C.; Vallejos, Rubén H.

    1989-01-01

    Monospecific polyclonal antibodies against thylakoid ferredoxin-NADP+ oxidoreductase and its binding protein from Spinacia oleracea were used to detect the presence of these proteins in different higher plants, including C3, C4, and Crassulacean acid metabolism species. A remarkable conservation of antigenic determinants in all the species analyzed was demonstrated for both the reductase and its binding protein. The association of these polypeptides in a complex was detected by immunoprecipitation. Images Figure 1 Figure 2 PMID:16666777

  17. Engineering sciences design. Design and implementation of components for a bioregenerative system for growing higher order plants in space

    NASA Technical Reports Server (NTRS)

    Nevill, Gale E., Jr.

    1989-01-01

    The primary goal was to address specific needs in the design of an integrated system to grow higher plants in space. With the needs defined, the emphasis was placed on the design and fabrication of devices to meet these needs. Specific attention was placed on a hand-held harvester, a nutrient concentration sensor, an air-water separator, and a closed-loop biological system simulation.

  18. Herbivore-Triggered Electrophysiological Reactions: Candidates for Systemic Signals in Higher Plants and the Challenge of Their Identification.

    PubMed

    Zimmermann, Matthias R; Mithöfer, Axel; Will, Torsten; Felle, Hubert H; Furch, Alexandra C U

    2016-04-01

    In stressed plants, electrophysiological reactions (elRs) are presumed to contribute to long-distance intercellular communication between distant plant parts. Because of the focus on abiotic stress-induced elRs in recent decades, biotic stress-triggered elRs have been widely ignored. It is likely that the challenge to identify the particular elR types (action potential [AP], variation potential, and system potential [SP]) was responsible for this course of action. Thus, this survey focused on insect larva feeding (Spodoptera littoralis and Manduca sexta) that triggers distant APs, variation potentials, and SPs in monocotyledonous and dicotyledonous plant species (Hordeum vulgare, Vicia faba, and Nicotiana tabacum). APs were detected only after feeding on the stem/culm, whereas SPs were observed systemically following damage to both stem/culm and leaves. This was attributed to the unequal vascular innervation of the plant and a selective electrophysiological connectivity of the plant tissue. However, striking variations in voltage patterns were detected for each elR type. Further analyses (also in Brassica napus and Cucurbita maxima) employing complementary electrophysiological approaches in response to different stimuli revealed various reasons for these voltage pattern variations: an intrinsic plasticity of elRs, a plant-specific signature of elRs, a specific influence of the applied (a)biotic trigger, the impact of the technical approach, and/or the experimental setup. As a consequence, voltage pattern variations, which are not irregular but rather common, need to be included in electrophysiological signaling analysis. Due to their widespread occurrence, systemic propagation, and respective triggers, elRs should be considered as candidates for long-distance communication in higher plants. PMID:26872949

  19. Comparative analysis of predicted plastid-targeted proteomes of sequenced higher plant genomes.

    PubMed

    Schaeffer, Scott; Harper, Artemus; Raja, Rajani; Jaiswal, Pankaj; Dhingra, Amit

    2014-01-01

    Plastids are actively involved in numerous plant processes critical to growth, development and adaptation. They play a primary role in photosynthesis, pigment and monoterpene synthesis, gravity sensing, starch and fatty acid synthesis, as well as oil, and protein storage. We applied two complementary methods to analyze the recently published apple genome (Malus × domestica) to identify putative plastid-targeted proteins, the first using TargetP and the second using a custom workflow utilizing a set of predictive programs. Apple shares roughly 40% of its 10,492 putative plastid-targeted proteins with that of the Arabidopsis (Arabidopsis thaliana) plastid-targeted proteome as identified by the Chloroplast 2010 project and ∼57% of its entire proteome with Arabidopsis. This suggests that the plastid-targeted proteomes between apple and Arabidopsis are different, and interestingly alludes to the presence of differential targeting of homologs between the two species. Co-expression analysis of 2,224 genes encoding putative plastid-targeted apple proteins suggests that they play a role in plant developmental and intermediary metabolism. Further, an inter-specific comparison of Arabidopsis, Prunus persica (Peach), Malus × domestica (Apple), Populus trichocarpa (Black cottonwood), Fragaria vesca (Woodland Strawberry), Solanum lycopersicum (Tomato) and Vitis vinifera (Grapevine) also identified a large number of novel species-specific plastid-targeted proteins. This analysis also revealed the presence of alternatively targeted homologs across species. Two separate analyses revealed that a small subset of proteins, one representing 289 protein clusters and the other 737 unique protein sequences, are conserved between seven plastid-targeted angiosperm proteomes. Majority of the novel proteins were annotated to play roles in stress response, transport, catabolic processes, and cellular component organization. Our results suggest that the current state of knowledge regarding

  20. Comparison of Large Subunits of Type II DNA-dependent RNA Polymerases from Higher Plants.

    PubMed

    Kidd, G H; Link, G; Bogorad, L

    1979-10-01

    Two-dimensional tryptic mapping of (125)I-labeled polypeptides has been employed to compare the large subunits of type II DNA-dependent RNA polymerases from maize, parsley (Petroselinum sativum), and wheat. Maps of the 220 kilodalton (kd) and 140 kd subunits from wheat RNA polymerase II differ from those of the corresponding subunits from parsley enzyme II. The 180 kd subunits from maize and parsley type II enzymes also yield dissimilar tryptic maps. Thus, despite similarities in molecular mass, the large subunits of wheat, parsley, and maize type II RNA polymerases are unique to each individual plant species. PMID:16661032

  1. Size, Shape, and Arrangement of Cellulose Microfibril in Higher Plant Cell Walls

    SciTech Connect

    Ding, S. Y.

    2013-01-01

    Plant cell walls from maize (Zea mays L.) are imaged using atomic force microscopy (AFM) at the sub-nanometer resolution. We found that the size and shape of fundamental cellulose elementary fibril (CEF) is essentially identical in different cell wall types, i.e., primary wall (PW), parenchyma secondary wall (pSW), and sclerenchyma secondary wall (sSW), which is consistent with previously proposed 36-chain model (Ding et al., 2006, J. Agric. Food Chem.). The arrangement of individual CEFs in these wall types exhibits two orientations. In PW, CEFs are horizontally associated through their hydrophilic faces, and the planar faces are exposed, forming ribbon-like macrofibrils. In pSW and sSW, CEFs are vertically oriented, forming layers, in which hemicelluloses are interacted with the hydrophobic faces of the CEF and serve as spacers between CEFs. Lignification occurs between CEF-hemicelluloses layers in secondary walls. Furthermore, we demonstrated quantitative analysis of plant cell wall accessibility to and digestibility by different cellulase systems at real-time using chemical imaging (e.g., stimulated Raman scattering) and fluorescence microscopy of labeled cellulases (Ding et al., 2012, Science, in press).

  2. Energetic metabolism response in algae and higher plant species from simulation experiments with the clinostat.

    PubMed

    Vasilenko, A; Popova, A F

    1996-01-01

    Adenylate state is acknowledged to be among the most convenient approaches in the study of physiological changes in plant cells under simulation of altered gravity condition with the clinostat. Adenylate levels and the ATP/ADP ratio in cytoplasmic and mitochondrial extracts of cultivated cells of Haplopappus gracilis and algae cells of Chlorella vulgaris under initial stages of the fast-rotating and slow-rotating clinorotation, as well as the long-term clinorotation, have been investigated. For analysis of ATP and ADP levels in the plant cells under the clinorotation, we applied a high-sensitive bioluminescence method using the luciferase and piruvate kinase enzyme systems. It has been shown that the adenylate ratio is already increased during at the start of clinorotation with the different speed of rotation in the biological material tested. The considerable changes in mitochondrial ultrastructure of Chlorella cells, as well as the rising ATP level and dropping of the ATP/ADP ratio appear after long-duration clinorotation if compared to control material. It is probably connected with the distinctions in ATP-synthetase functioning in mitochondria of the cells under the clinorotation conditions. PMID:11538600

  3. Quantification and Localization of S-Nitrosothiols (SNOs) in Higher Plants.

    PubMed

    Barroso, Juan B; Valderrama, Raquel; Carreras, Alfonso; Chaki, Mounira; Begara-Morales, Juan C; Sánchez-Calvo, Beatriz; Corpas, Francisco J

    2016-01-01

    S-nitrosothiols (SNOs) are a family of molecules produced by the reaction of nitric oxide (NO) with -SH thiol groups present in the cysteine residues of proteins and peptides caused by a posttranslational modification (PTM) known as S-nitrosylation (strictly speaking S-nitrosation) that can affect the cellular function of proteins. These molecules are a relatively more stable form of NO and consequently can act as a major intracellular NO reservoir and, in some cases, as a long-distance NO signal. Additionally, SNOs can be transferred between small peptides and protein thiol groups through S-transnitrosylation mechanisms. Thus, detection and cellular localization of SNOs in plant cells can be useful tools to determine how these molecules are modulated under physiological and adverse conditions and to determine their importance as a mechanism for regulating different biochemical pathways. Using a highly sensitive chemiluminescence ozone technique and a specific fluorescence probe (Alexa Fluor 488 Hg-link phenylmercury), the methods described in this chapter enable us to determine SNOs in an nM range as well as their cellular distribution in the tissues of different plant species. PMID:27094417

  4. Energetic metabolism response in algae and higher plant species from simulation experiments with the clinostat

    NASA Astrophysics Data System (ADS)

    Vasilenko, A.; Popova, A. F.

    Adenylate state is acknowledged to be among the most convenient approaches in the study of physiological changes in plant cells under simulation of altered gravity condition with the clinostat. Adenylate levels and the ATP/ADP ratio in cytoplasmic and mitochondrial extracts of cultivated cells of Haplopappus gracilis and algae cells of Chlorella vulgaris under initial stages of the fast-rotating and slow-rotating clinorotation, as well as the long-term clinorotation, have been investigated. For analysis of ATP and ADP levels in the plant cells under the clinorotation, we applied a high-sensitive bioluminescence method using the luciferase and piruvate kinase enzyme systems. It has been shown that the adenylate ratio is already increased during at the start of clinorotation with the different speed of rotation in the biological material tested. The considerable changes in mitochondrial ultrastructure of Chlorella cells, as well as the rising ATP level and dropping of the ATP/ADP ratio appear after long-duration clinorotation if compared to control material. It is probably connected with the distinctions in ATP-synthetase functioning in mitochondria of the cells under the clinorotation conditions.

  5. Attempts to detect cyclic adenosine 3':5'-monophosphate in higher plants by three assay methods.

    PubMed

    Bressan, R A; Ross, C W

    1976-01-01

    Endogenous levels of cyclic adenosine-3':5'-monophosphate in coleoptile first leaf segments of oat (Avena sativa L.), potato (Solanum tuberosum L.) tubers, tobacco (Nicotiana tabacum L.) callus, and germinating seeds of lettuce (Lactuca sativa L.) were measured with a modified Gilman binding assay and a protein kinase activation assay. The incorporation of adenosine-8-(14)C into compounds with properties similar to those of cyclic AMP was also measured in studies with germinating lettuce seeds. The binding assay proved reliable for mouse and rat liver analyses, but was nonspecific for plant tissues. It responded to various components from lettuce and potato tissues chromatographically similar to but not identical with cyclic AMP. The protein kinase activation assay was much more specific, but it also exhibited positive responses in the presence of compounds not chromatographically identical to cyclic AMP. The concentrations of cyclic AMP in the plant tissues tested were at the lower limits of detection and characterization obtainable with these assays. The estimates of maximal levels were much lower than reported in many previous studies. PMID:16659419

  6. Electron flow to oxygen in higher plants and algae: rates and control of direct photoreduction (Mehler reaction) and rubisco oxygenase.

    PubMed

    Badger, M R; von Caemmerer, S; Ruuska, S; Nakano, H

    2000-10-29

    Linear electron transport in chloroplasts produces a number of reduced components associated with photosystem I (PS I) that may subsequently participate in reactions that reduce O2. The two primary reactions that have been extensively studied are: first, the direct reduction of O2 to superoxide by reduced donors associated with PS I (the Mehler reaction), and second, the rubisco oxygenase (ribulose 1,5-bisphosphate carboxylase oxygenase EC 4.1.1.39) reaction and associated peroxisomal and mitochondrial reactions of the photorespiratory pathway. This paper reviews a number of recent and past studies with higher plants, algae and cyanobacteria that have attempted to quantify O2 fluxes under various conditions and their contributions to a number of roles, including photon energy dissipation. In C3 and Crassulacean acid metabolism (CAM) plants, a Mehler O2 uptake reaction is unlikely to support a significant flow of electron transport (probably less than 10%). In addition, if it were present it would appear to scale with photosynthetic carbon oxidation cycle (PCO) and photosynthetic carbon reduction cycle (PCR) activity This is supported by studies with antisense tobacco plants with reduced rubisco at low and high temperatures and high light, as well as studies with potatoes, grapes and madrone during water stress. The lack of significant Mehler in these plants directly argues for a strong control of Mehler reaction in the absence of ATP consumption by the PCR and PCO cycles. The difference between C3 and C4 plants is primarily that the level of light-dependent O2 uptake is generally much lower in C4 plants and is relatively insensitive to the external CO2 concentration. Such a major difference is readily attributed to the operation of the C4 CO2 concentrating mechanism. Algae show a range of light-dependent O2 uptake rates, similar to C4 plants. As in C4 plants, the O2 uptake appears to be largely insensitive to CO2, even in species that lack a CO2 concentrating

  7. An empirical review: Characteristics of plant microsatellite markers that confer higher levels of genetic variation1

    PubMed Central

    Merritt, Benjamin J.; Culley, Theresa M.; Avanesyan, Alina; Stokes, Richard; Brzyski, Jessica

    2015-01-01

    During microsatellite marker development, researchers must choose from a pool of possible primer pairs to further test in their species of interest. In many cases, the goal is maximizing detectable levels of genetic variation. To guide researchers and determine which markers are associated with higher levels of genetic variation, we conducted a literature review based on 6782 genomic microsatellite markers published from 1997–2012. We examined relationships between heterozygosity (He or Ho) or allele number (A) with the following marker characteristics: repeat type, motif length, motif region, repeat frequency, and microsatellite size. Variation across taxonomic groups was also analyzed. There were significant differences between imperfect and perfect repeat types in A and He. Dinucleotide motifs exhibited significantly higher A, He, and Ho than most other motifs. Repeat frequency and motif region were positively correlated with A, He, and Ho, but correlations with microsatellite size were minimal. Higher taxonomic groups were disproportionately represented in the literature and showed little consistency. In conclusion, researchers should carefully consider marker characteristics so they can be tailored to the desired application. If researchers aim to target high genetic variation, dinucleotide motif lengths with large repeat frequencies may be best. PMID:26312192

  8. Antimicrobial agents from higher plants. The antimicrobially inactive components of Ptelea trifoliata L.

    PubMed

    Mitscher, L A; Bathala, M S; Clark, G W; Beal, J L

    1975-01-01

    From the weakly antibacterial non-quaternary alkaloidal fractions from Ptelea trifoliata L. (Rutaceae), ten tertiary quinol-2-one and quinol-4-one alkaloids were isolated and identified. In addition, beta-sitosterol, beta-sitosteryl-beta-D-glucoside and bergapten were isolated. None of these compounds possessed perceptible antimicrobial activity. The weak antimicrobial activity of the neutral and alkaloidal fractions was traced to small amounts of pteleatinium chloride which had not been completely separated by bulk processes. Alkaloids previously known to be present in P. trifoliata which were found in this study ptelefoline methyl ether, pteleine and skimmianine. Alkaloids previously known but new to this plant were lunidoine and isomaculasidine. Alkaloids newly found in nature were neohydroxylunine, hydroxylunidonine, 6-methoxylunidoine, 6-methoxylunineand 6-methoxy-hydroxylunidine. The structure of the latter three bases is proposed tentatively. PMID:1134209

  9. [Proteolytic enzymes and trypsin inhibitors of higher plants under stress conditions].

    PubMed

    Domash, V I; Sharpio, T P; Zabreĭko, S A; Sosnovskaia, T F

    2008-01-01

    The response of the components of a protease-inhibitor system of legume and cereal crops to stress factors was studied. It was found that salinization, heavy metal ions, and phytopathogenic flora inhibit the activity of neutral, acidic, and alkaline proteases at early stages of seed germination, the degree of the inhibition of the endoprotease activity being dependent on the index of tolerance of legume and cereal crops. It was shown that, in response to unfavorable conditions, accumulation of trypsin inhibitors occurs, which is accompanied by the appearance of new protein components, as indicated by electrophoresis. The results confirm the presumption that serine protease inhibitors are involved in the response of plants to stress factors. PMID:18672684

  10. The Role of Silicon in Higher Plants under Salinity and Drought Stress

    PubMed Central

    Coskun, Devrim; Britto, Dev T.; Huynh, Wayne Q.; Kronzucker, Herbert J.

    2016-01-01

    Although deemed a “non-essential” mineral nutrient, silicon (Si) is clearly beneficial to plant growth and development, particularly under stress conditions, including salinity and drought. Here, we review recent research on the physiological, biochemical, and molecular mechanisms underlying Si-induced alleviation of osmotic and ionic stresses associated with salinity and drought. We distinguish between changes observed in the apoplast (i.e., suberization, lignification, and silicification of the extracellular matrix; transpirational bypass flow of solutes and water), and those of the symplast (i.e., transmembrane transport of solutes and water; gene expression; oxidative stress; metabolism), and discuss these features in the context of Si biogeochemistry and bioavailability in agricultural soils, evaluating the prospect of using Si fertilization to increase crop yield and stress tolerance under salinity and drought conditions. PMID:27486474

  11. Regulation of sucrose metabolism in higher plants: localization and regulation of activity of key enzymes

    NASA Technical Reports Server (NTRS)

    Winter, H.; Huber, S. C.; Brown, C. S. (Principal Investigator)

    2000-01-01

    Sucrose (Suc) plays a central role in plant growth and development. It is a major end product of photosynthesis and functions as a primary transport sugar and in some cases as a direct or indirect regulator of gene expression. Research during the last 2 decades has identified the pathways involved and which enzymes contribute to the control of flux. Availability of metabolites for Suc synthesis and 'demand' for products of sucrose degradation are important factors, but this review specifically focuses on the biosynthetic enzyme sucrose-phosphate synthase (SPS), and the degradative enzymes, sucrose synthase (SuSy), and the invertases. Recent progress has included the cloning of genes encoding these enzymes and the elucidation of posttranslational regulatory mechanisms. Protein phosphorylation is emerging as an important mechanism controlling SPS activity in response to various environmental and endogenous signals. In terms of Suc degradation, invertase-catalyzed hydrolysis generally has been associated with cell expansion, whereas SuSy-catalyzed metabolism has been linked with biosynthetic processes (e.g., cell wall or storage products). Recent results indicate that SuSy may be localized in multiple cellular compartments: (1) as a soluble enzyme in the cytosol (as traditionally assumed); (2) associated with the plasma membrane; and (3) associated with the actin cytoskeleton. Phosphorylation of SuSy has been shown to occur and may be one of the factors controlling localization of the enzyme. The purpose of this review is to summarize some of the recent developments relating to regulation of activity and localization of key enzymes involved in sucrose metabolism in plants.

  12. Thermal stability of higher plant biomarkers evaluated through pyrolysis; geologic implications in thermally-mature sediment

    NASA Astrophysics Data System (ADS)

    Longbottom, T. L.; Hockaday, W. C.; Von Bargen, J.

    2013-12-01

    The organic molecules known as n-alkanes, n-alkanoic acids, and sterols are widely used biomarkers in paleoecological and organic matter source-apportionment studies, and are complementary to traditional bulk organic matter proxies (organic carbon stable isotopes and C/N ratios). These organic matter parameters are hindered by early and late diagenesis, through a combination of biotic and abiotic factors, which can lead to uncertainty in sediments on geologic timescales. This study seeks to use modern central Texas plants and soils as tools for our understanding and interpretation of biomarker patterns deep time, specifically in thermally mature sediment and paleosols. Bulk leaf and soil samples were heat treated to a range of temperatures in a muffle furnace in the absence of oxygen in order to clarify the role of abiotic degradation (thermal cracking) on bulk SOM and biomarker distributions. Preliminary results for unaltered n-alkane distributions of Southern Cattail (Typha domingensis) biomass shows a strong odd-over-even predominance, where the most abundant n-alkanes are nC23, nC25, nC27, and nC29. The biomass exposed to slow pyrolysis temperature of 300°C had n-alkanes ranging from nC11-nC29, with no odd-over-even predominance. The high abundance of lower molecular weight n-alkanes (plant material is severely disrupted by modest heating, an observation that must be taken into account when interpreting these biomarkers in deeply-buried geological samples.

  13. Tolerance of chufa (Cyperus esculentus L.) plants, representing the higher plant compartment in bioregenerative life support systems, to super-optimal air temperatures

    NASA Astrophysics Data System (ADS)

    Shklavtsova, E. S.; Ushakova, S. A.; Shikhov, V. N.; Anishchenko, O. V.

    2013-01-01

    Plants intended to be included in the photosynthesizing compartment of the bioregenerative life support system (BLSS) need to be studied in terms of both their production parameters under optimal conditions and their tolerance to stress factors that might be caused by emergency situations. The purpose of this study was to investigate tolerance of chufa (Cyperus esculentus L.) plants to the super-optimal air temperature of 45 ± 1 °C as dependent upon PAR (photosynthetically active radiation) intensity and the duration of the exposure to the stress factor. Chufa plants were grown hydroponically, on expanded clay, under artificial light. The nutrient solution was Knop's mineral medium. Until the plants were 30 days old, they had been grown at 690 μmol m-2 s-1 PAR and air temperature 25 °C. Thirty-day-old plants were exposed to the temperature 45 °C for 6 h, 20 h, and 44 h at PAR intensities 690 μmol m-2 s-1 and 1150 μmol m-2 s-1. The exposure to the damaging air temperature for 44 h at 690 μmol m-2 s-1 PAR caused irreversible damage to PSA, resulting in leaf mortality. In chufa plants exposed to heat shock treatment at 690 μmol m-2 s-1 PAR for 6 h and 20 h, respiration exceeded photosynthesis, and CO2 release in the light was recorded. Functional activity of photosynthetic apparatus, estimated from parameters of pulse-modulated chlorophyll fluorescence in Photosystem 2 (PS 2), decreased 40% to 50%. After the exposure to the stress factor was finished, functional activity of PSA recovered its initial values, and apparent photosynthesis (Papparent) rate after a 20-h exposure to the stress factor was 2.6 times lower than before the elevation of the temperature. During the first hours of plant exposure to the temperature 45 °C at 1150 μmol m-2 s-1 PAR, respiration rate was higher than photosynthesis rate, but after 3-4 h of the exposure, photosynthetic processes exceeded oxidative ones and CO2 absorption in the light was recorded. At the end of the 6-h exposure

  14. Inclusion of human mineralized exometabolites and fish wastes as a source of higher plant mineral nutrition in BTLSS mass exchange

    NASA Astrophysics Data System (ADS)

    Tikhomirova, Natalia; Tikhomirov, Alexander A.; Ushakova, Sofya; Anischenko, Olesya; Trifonov, Sergey V.

    Human exometabolites inclusion into an intrasystem mass exchange will allow increasing of a closure level of a biological-technical life support system (BTLSS). Previously at the IBP SB RAS it was shown that human mineralized exometabolites could be incorporated in the BTLSS mass exchange as a mineral nutrition source for higher plants. However, it is not known how that combined use of human mineralized exometabolites and fish wastes in the capacity of nutrient medium, being a part of the BTLSS consumer wastes, will affect the plant productivity. Several wheat vegetations were grown in an uneven-aged conveyor on a neutral substrate. A mixture of human mineralized exometabolites and fish wastes was used as a nutrient solution in the experiment treatment and human mineralized exometabolites were used in the control. Consequently, a high wheat yield in the experiment treatment practically equal to the control yield was obtained. Thus, mineralized fish wastes can be an additional source of macro-and micronutrients for plants, and use of such wastes for the plant mineral nutrition allows increasing of BTLSS closure level.

  15. Genetic engineering of corn and other higher plants: Progress report for the period August 1, 1984--July 31, 1985

    SciTech Connect

    Davis, R.W.

    1985-01-01

    We have developed a number of potential vectors for maize transformation. All vectors have used the bacterial CAT gene connected between a maize promoter and a maize polyadenylation site. The product of this gene is readily assayed in maize tissue and may provide a fast screen for young seedlings. We have found that chloramphenicol reduces the growth of young seedlings and causes bleaching of the first leaves, but does not kill the plant. A mosaic with a transforming DNA may allow better growth. We remove a portion of the root to assay for CAT activity. CAT activity should be detected even if only a small number of cells contain DNA. If activity is detected in these young plants, the plant will be potted, and F1 and F2 plants will be generated. These will then be screened for stable inheritance of the transforming DNA. The higher the expression of the CAT gene in these few cells, the more reliable will be the assay. Accordingly, we have connected the CAT gene to one of the strongest maize promoters active in the young seedling. This promoter was identified in a large scale screening operation that identified the single copy gene that expressed the most abundant polyA RNA. The promoter and coding regions have been sequenced. The product of this gene has not yet been determined.

  16. Visible light-induced oxidation of unsaturated components of cutins: a significant process during the senescence of higher plants.

    PubMed

    Rontani, Jean-François; Rabourdin, Adélaïde; Pinot, Franck; Kandel, Sylvie; Aubert, Claude

    2005-02-01

    9-Hydroperoxy-18-hydroxyoctadec-10(trans)-enoic and 10-hydroperoxy-18-hydroxyoctadec-8(trans)-enoic acids deriving from type II (i.e. involving 1O2) photooxidation of 18-hydroxyoleic acid were detected after visible light-induced senescence experiments carried out with Petroselinum sativum and subsequent cutin depolymerisation. These results showed that in senescent plants, where the 1O2 formation rate exceeds the quenching capacity of the photoprotective system, 1O2 can migrate outside the chloroplasts and affect the unsaturated components of cutins. Significant amounts of 9,18-dihydroxyoctadec-10(trans)-enoic and 10,18-dihydroxyoctadec-8(trans)-enoic acids resulting from the reduction of these photoproducts of 18-hydroxyoleic acid were also detected in different natural samples. These results well support the significance of the photooxidation of the unsaturated components of higher plant cutins in the natural environment. PMID:15680988

  17. Transport of phosphocholine in higher plant cells: sup 31 P nuclear magnetic resonance studies

    SciTech Connect

    Gout, E.; Bligny, R.; Roby, C.; Douce, R. )

    1990-06-01

    Phosphocholine (PC) is an abundant primary form of organic phosphate that is transported in plant xylem sap. Addition of PC to the perfusate of compressed P{sub i}-starved sycamore cells monitored by {sup 31}P NMR spectroscopy resulted in an accumulation of PC and all the other phosphate esters in the cytoplasmic compartment. Addition of hemicholinium-3, an inhibitor of choline uptake, to the perfusate inhibited PC accumulation but not inorganic phosphate (P{sub i}). When the P{sub i}-starved cells were perfused with a medium containing either P{sub i} or PC, the resulting P{sub i} distribution in the cell was the same. Addition of choline instead of PC to the perfusate of compressed cells resulted in an accumulation of PC in the cytoplasmic compartment from choline kinase activity. In addition, PC phosphatase activity has been discovered associated with the cell wall. These results indicate that PC was rapidly hydrolyzed outside the cell and that choline and P{sub i} entered the cytosolic compartment where choline kinase re-forms PC.

  18. Herbicides do not ensure for higher wheat yield, but eliminate rare plant species

    PubMed Central

    Gaba, Sabrina; Gabriel, Edith; Chadœuf, Joël; Bonneu, Florent; Bretagnolle, Vincent

    2016-01-01

    Weed control is generally considered to be essential for crop production and herbicides have become the main method used for weed control in developed countries. However, concerns about harmful environmental consequences have led to strong pressure on farmers to reduce the use of herbicides. As food demand is forecast to increase by 50% over the next century, an in-depth quantitative analysis of crop yields, weeds and herbicides is required to balance economic and environmental issues. This study analysed the relationship between weeds, herbicides and winter wheat yields using data from 150 winter wheat fields in western France. A Bayesian hierarchical model was built to take account of farmers’ behaviour, including implicitly their perception of weeds and weed control practices, on the effectiveness of treatment. No relationship was detected between crop yields and herbicide use. Herbicides were found to be more effective at controlling rare plant species than abundant weed species. These results suggest that reducing the use of herbicides by up to 50% could maintain crop production, a result confirmed by previous studies, while encouraging weed biodiversity. Food security and biodiversity conservation may, therefore, be achieved simultaneously in intensive agriculture simply by reducing the use of herbicides. PMID:27453451

  19. Photoprotection and triplet energy transfer in higher plants: the role of electronic and nuclear fluctuations.

    PubMed

    Cupellini, Lorenzo; Jurinovich, Sandro; Prandi, Ingrid G; Caprasecca, Stefano; Mennucci, Benedetta

    2016-04-20

    Photosynthetic organisms employ several photoprotection strategies to avoid damage due to the excess energy in high light conditions. Among these, quenching of triplet chlorophylls by neighboring carotenoids (Cars) is fundamental in preventing the formation of singlet oxygen. Cars are able to accept the triplets from chlorophylls by triplet energy transfer (TET). We have here studied TET rates in CP29, a minor light-harvesting complex (LHC) of the Photosystem II in plants. A fully atomistic strategy combining classical molecular dynamics of the LHC in its natural environment with a hybrid time-dependent density functional theory/polarizable MM description of the TET is used. We find that the structural fluctuations of the pigment-protein complex can largely enhance the transfer rates with respect to those predicted using the crystal structure, reducing the triplet quenching times in the subnanosecond scale. These findings add a new perspective for the interpretation of the photoprotection function and its relation with structural motions of the LHC. PMID:27052105

  20. Herbicides do not ensure for higher wheat yield, but eliminate rare plant species.

    PubMed

    Gaba, Sabrina; Gabriel, Edith; Chadœuf, Joël; Bonneu, Florent; Bretagnolle, Vincent

    2016-01-01

    Weed control is generally considered to be essential for crop production and herbicides have become the main method used for weed control in developed countries. However, concerns about harmful environmental consequences have led to strong pressure on farmers to reduce the use of herbicides. As food demand is forecast to increase by 50% over the next century, an in-depth quantitative analysis of crop yields, weeds and herbicides is required to balance economic and environmental issues. This study analysed the relationship between weeds, herbicides and winter wheat yields using data from 150 winter wheat fields in western France. A Bayesian hierarchical model was built to take account of farmers' behaviour, including implicitly their perception of weeds and weed control practices, on the effectiveness of treatment. No relationship was detected between crop yields and herbicide use. Herbicides were found to be more effective at controlling rare plant species than abundant weed species. These results suggest that reducing the use of herbicides by up to 50% could maintain crop production, a result confirmed by previous studies, while encouraging weed biodiversity. Food security and biodiversity conservation may, therefore, be achieved simultaneously in intensive agriculture simply by reducing the use of herbicides. PMID:27453451

  1. Reorganization of Thylakoid Components during Chloroplast Development in Higher Plants after Transfer to Darkness 1

    PubMed Central

    Akoyunoglou, Agapios; Akoyunoglou, George

    1985-01-01

    It was shown earlier that in etiolated bean (Phaseolus vulgaris, var. red kidney) leaves exposed to continuous light for a short time and then transferred to darkness a reorganization of their photosystem II (PSII) unit components occurs. This reorganization involves disorganization of the light-harvesting complex of PSII (LHC-II), destruction of its chlorophyll b and the 25 kilodalton polypeptide, and reuse of its chlorophyll a for the formation of additional, small in size, PSII units (Argyroudi-Akoyunoglou, Akoyunoglou, Kalosakas, Akoyunoglou 1982 Plant Physiol 70: 1242-1248). The present study further shows that parallel to the PSII unit reorganization a reorganization of the PSI unit components also occurs: upon transfer to darkness the 24, 23, and 21 kilodalton polypeptides, components of the light-harvesting complex of PSI (LHC-I), are decreased, the 69 kilodalton polypeptide, component of the chlorophyll a-rich P700-protein complex (CPI), is increased and new smallsized PSI units are formed. Concomitantly, the cytochrome f/chlorophyll and the cytochrome b/chlorophyll ratios are gradually increased. This suggests that the concentration of the electron transport components is also modulated in darkness to allow for adequate electron flow to occur between the newly synthesized PSII and PSI units. Images Fig. 2 Fig. 3 PMID:16664426

  2. Cytosine methylation of plastid genome in higher plants. Fact or artefact?

    PubMed

    Fojtová, M; Kovarík, A; Matyásek, R

    2001-03-01

    DNA methylation of chloroplast genome has been studied in a large variety of angiosperm species using restriction enzyme analysis of three genomic loci (totally encompassing about 10% of chloroplast genome) and bisulfite genomic sequencing of tobacco ribulose bisphosphate carboxylase/oxygenase (large subunit) gene (rbcL). Except for CCWGG (W=A or T) sites that were partially refractory to the cleavage with methylation sensitive EcoRII in all loci, no cytosine methylation was found at the CCGG (MspI/HpaII) and several other restriction sites tested. However, EcoRII was unable to completely digest an unmethylated CCWGG site in the cloned rbcL gene on plasmid. Further a bisulfite genomic sequencing performed on EcoRII-restricted DNA failed to show any 5-methylcytosine either within or outside inspected EcoRII sites along the 3' end of rbcL coding region. In conclusion our results do not support evidence for methylated cytosine residues in plant chloroplast genomes and we suggest that results obtained with EcoRII should be interpreted with great care especially when small differences in methylation levels are analysed. PMID:11448733

  3. [The ecological, taxonomic and biotechnology aspects of research on bacteria and higher plants that produce biologically active substances].

    PubMed

    Smirnov, V V

    1998-01-01

    The paper deals with the basic results of scientific activity of the Department of Antibiotics at the Institute of Microbiology and Virology of the National Academy of Sciences of Ukraine for the last two decades. Results of fundamental ecological and taxonomical investigations of bacteria of the Pseudomonas and Bacillus genera, study of regularities in formation of antibiotics and other biologically active substances by microorganism of these taxa and by higher plants have been presented; new antibiotics, probiotics and other biopreparations developed at the Department during this period have been characterized. PMID:10077953

  4. Transport and phosphorylation of choline in higher plant cells. Phosphorus-31 nuclear magnetic resonance studies

    SciTech Connect

    Bligny, R.; Foray, M.F.; Roby, C.; Douce, R.

    1989-03-25

    When sycamore cells were suspended in basal medium containing choline, the latter was taken up by the cells very rapidly. A facilitated diffusion system appertained at low concentrations of choline and exhibited Michaelis-Menten kinetics. At higher choline concentrations simple diffusion appeared to be the principal mode of uptake. Addition of choline to the perfusate of compressed sycamore cells monitored by /sup 31/P NMR spectroscopy resulted in a dramatic accumulation of P-choline in the cytoplasmic compartment containing choline kinase and not in the vacuole. The total accumulation of P-choline over a 10-h period exhibited Michaelis-Menten kinetics. During this period, in the absence of Pi in the perfusion medium there was a marked depletion of glucose-6-P, and the cytoplasmic Pi resonance disappeared almost completely. When a threshold of cytoplasmic Pi was attained, the phosphorylation of choline was sustained by the continuous release of Pi from the vacuole although at a much lower rate. However, when 100 microM inorganic phosphate was present in the perfusion medium, externally added Pi was preferentially used to sustain P-choline synthesis. It is clear, therefore, that cytosolic choline kinase associated with a carrier-mediated transport system for choline uptake appeared as effective systems for continuously trapping cytoplasmic Pi including vacuolar Pi entering the cytoplasm.

  5. Amino acids implicated in plant defense are higher in Candidatus Liberibacter asiaticus-tolerant citrus varieties.

    PubMed

    Killiny, Nabil; Hijaz, Faraj

    2016-04-01

    Citrus Huanglongbing (HLB), also known as citrus greening, has been threatening the citrus industry since the early 1900's and up to this date there are no effective cures for this disease. Field observations and greenhouse controlled studies demonstrated that some citrus genotypes are more tolerant to Candidatus Liberibacter asiaticus (CLas) pathogen than others. However, the mechanisms underpinning tolerance has not been determined yet. The phloem sap composition of CLas-tolerant and sensitive citrus varieties was studied to identify metabolites that could be responsible for their tolerance to CLas. The citrus phloem sap was collected by centrifugation and was analyzed with gas chromatography-mass spectrometry after methyl chloroformate derivatization. Thirty-three metabolites were detected in the phloem sap of the studied varieties: twenty 20 amino acids, eight 8 organic acids, and five 5 fatty acids. Interestingly, the levels of most amino acids, especially those implicated in plantdefense to pathogens such as phenylalanine, tyrosine, tryptophan, lysine, and asparagine were higher in tolerant varieties. Although the level of organic acids varied between cultivars, this variation was not correlated with citrus resistance to CLas and could be cultivar specific. The fatty acids were found in trace amounts and in most cases their levels were not significantly different among varieties. Better understanding of the mechanisms underpinning citrus tolerance to CLas will help in developing economically tolerant varieties. PMID:27057814

  6. Zeaxanthin Radical Cation Formation in Minor Light-Harvesting Complexes of Higher Plant Antenna

    SciTech Connect

    Avenson, Thomas H.; Ahn, Tae Kyu; Zigmantas, Donatas; Niyogi, Krishna K.; Li, Zhirong; Ballottari, Matteo; Bassi, Roberto; Fleming, Graham R.

    2008-01-31

    Previous work on intact thylakoid membranes showed that transient formation of a zeaxanthin radical cation was correlated with regulation of photosynthetic light-harvesting via energy-dependent quenching. A molecular mechanism for such quenching was proposed to involve charge transfer within a chlorophyll-zeaxanthin heterodimer. Using near infrared (880-1100 nm) transient absorption spectroscopy, we demonstrate that carotenoid (mainly zeaxanthin) radical cation generation occurs solely in isolated minor light-harvesting complexes that bind zeaxanthin, consistent with the engagement of charge transfer quenching therein. We estimated that less than 0.5percent of the isolated minor complexes undergo charge transfer quenching in vitro, whereas the fraction of minor complexes estimated to be engaged in charge transfer quenching in isolated thylakoids was more than 80 times higher. We conclude that minor complexes which bind zeaxanthin are sites of charge transfer quenching in vivo and that they can assume Non-quenching and Quenching conformations, the equilibrium LHC(N)<--> LHC(Q) of which is modulated by the transthylakoid pH gradient, the PsbS protein, and protein-protein interactions.

  7. Hydrogen peroxide generation by higher plant mitochondria oxidizing complex I or complex II substrates.

    PubMed

    Braidot, E; Petrussa, E; Vianello, A; Macri, F

    1999-05-28

    The generation of H2O2 by isolated pea stem mitochondria, oxidizing either malate plus glutamate or succinate, was examined. The level of H2O2 was almost one order of magnitude higher when mitochondria were energized by succinate. The succinate-dependent H2O2 formation was abolished by malonate, but unaffected by rotenone. The lack of effect of the latter suggests that pea mitochondria were working with a proton motive force below the threshold value required for reverse electron transfer. The activation by pyruvate of the alternative oxidase was reflected in an inhibition of H2O2 formation. This effect was stronger when pea mitochondria oxidized malate plus glutamate. Succinate-dependent H2O2 formation was ca. four times lower in Arum sp. mitochondria (known to have a high alternative oxidase) than in pea mitochondria. An uncoupler (FCCP) completely prevented succinate-dependent H2O2 generation, while it only partially (40-50%) inhibited that linked to malate plus glutamate. ADP plus inorganic phosphate (transition from state 4 to state 3) also inhibited the succinate-dependent H2O2 formation. Conversely, that dependent on malate plus glutamate oxidation was unaffected by low and stimulated by high concentrations of ADP. These results show that the main bulk of H2O2 is formed during substrate oxidation at the level of complex II and that this generation may be prevented by either dissipation of the electrochemical proton gradient (uncoupling and transition state 4-state 3), or preventing its formation (alternative oxidase). Conversely, H2O2 production, dependent on oxidation of complex I substrate, is mainly lowered by the activation of the alternative oxidase. PMID:10371218

  8. Gamma-ray optical counterpart search experiment (GROCSE)

    SciTech Connect

    Akerlof, C.; Fatuzzo, M.; Lee, B.; Bionta, R.; Ledebuhr, A.; Park, H.S.; Barthelmy, S.; Cline, T.; Gehrels, N.

    1993-12-15

    The requirements of a gamma-ray burst optical counterpart detector are reviewed. By taking advantage of real-time notification of bursts, new instruments can make sensitive searches while the gamma-ray transient is still in progress. A wide field of view camera at Livermore National Laboratories has recently been adapted for detecting GRB optical counterparts to a limiting magnitude of 8. A more sensitive camera, capable of reaching m{sub upsilon} = 14, is under development.

  9. Keck/MOSFIRE spectroscopy of five ULX counterparts

    NASA Astrophysics Data System (ADS)

    Heida, M.; Jonker, P. G.; Torres, M. A. P.; Roberts, T. P.; Walton, D. J.; Moon, D.-S.; Stern, D.; Harrison, F. A.

    2016-06-01

    We present H-band spectra of the candidate counterparts of five ultraluminous X-ray sources (ULXs; two in NGC 925, two in NGC 4136 and Holmberg II X-1) obtained with Keck/MOSFIRE (Multi-Object Spectrometer for Infra-Red Exploration). The candidate counterparts of two ULXs (J022721+333500 in NGC 925 and J120922+295559 in NGC 4136) have spectra consistent with (M-type) red supergiants (RSGs). We obtained two epochs of spectroscopy of the candidate counterpart to J022721+333500, separated by 10 months, but discovered no radial velocity variations with a 2σ upper limit of 40 km s-1. If the RSG is the donor star of the ULX, the most likely options are that either the system is seen at low inclination (<40°) or the black hole mass is less than 100 M⊙, unless the orbital period is longer than 6 years, in which case the obtained limit is not constraining. The spectrum of the counterpart to J120922+295559 shows emission lines on top of its stellar spectrum, and the remaining three counterparts do not show absorption lines that can be associated with the atmosphere of a star; their spectra are instead dominated by emission lines. Those counterparts with RSG spectra may be used in the future to search for radial velocity variations, and, if those are present, determine dynamical constraints on the mass of the accretor.

  10. Organic Acids: The Pools of Fixed Carbon Involved in Redox Regulation and Energy Balance in Higher Plants

    PubMed Central

    Igamberdiev, Abir U.; Eprintsev, Alexander T.

    2016-01-01

    Organic acids are synthesized in plants as a result of the incomplete oxidation of photosynthetic products and represent the stored pools of fixed carbon accumulated due to different transient times of conversion of carbon compounds in metabolic pathways. When redox level in the cell increases, e.g., in conditions of active photosynthesis, the tricarboxylic acid (TCA) cycle in mitochondria is transformed to a partial cycle supplying citrate for the synthesis of 2-oxoglutarate and glutamate (citrate valve), while malate is accumulated and participates in the redox balance in different cell compartments (via malate valve). This results in malate and citrate frequently being the most accumulated acids in plants. However, the intensity of reactions linked to the conversion of these compounds can cause preferential accumulation of other organic acids, e.g., fumarate or isocitrate, in higher concentrations than malate and citrate. The secondary reactions, associated with the central metabolic pathways, in particularly with the TCA cycle, result in accumulation of other organic acids that are derived from the intermediates of the cycle. They form the additional pools of fixed carbon and stabilize the TCA cycle. Trans-aconitate is formed from citrate or cis-aconitate, accumulation of hydroxycitrate can be linked to metabolism of 2-oxoglutarate, while 4-hydroxy-2-oxoglutarate can be formed from pyruvate and glyoxylate. Glyoxylate, a product of either glycolate oxidase or isocitrate lyase, can be converted to oxalate. Malonate is accumulated at high concentrations in legume plants. Organic acids play a role in plants in providing redox equilibrium, supporting ionic gradients on membranes, and acidification of the extracellular medium. PMID:27471516

  11. Organic Acids: The Pools of Fixed Carbon Involved in Redox Regulation and Energy Balance in Higher Plants.

    PubMed

    Igamberdiev, Abir U; Eprintsev, Alexander T

    2016-01-01

    Organic acids are synthesized in plants as a result of the incomplete oxidation of photosynthetic products and represent the stored pools of fixed carbon accumulated due to different transient times of conversion of carbon compounds in metabolic pathways. When redox level in the cell increases, e.g., in conditions of active photosynthesis, the tricarboxylic acid (TCA) cycle in mitochondria is transformed to a partial cycle supplying citrate for the synthesis of 2-oxoglutarate and glutamate (citrate valve), while malate is accumulated and participates in the redox balance in different cell compartments (via malate valve). This results in malate and citrate frequently being the most accumulated acids in plants. However, the intensity of reactions linked to the conversion of these compounds can cause preferential accumulation of other organic acids, e.g., fumarate or isocitrate, in higher concentrations than malate and citrate. The secondary reactions, associated with the central metabolic pathways, in particularly with the TCA cycle, result in accumulation of other organic acids that are derived from the intermediates of the cycle. They form the additional pools of fixed carbon and stabilize the TCA cycle. Trans-aconitate is formed from citrate or cis-aconitate, accumulation of hydroxycitrate can be linked to metabolism of 2-oxoglutarate, while 4-hydroxy-2-oxoglutarate can be formed from pyruvate and glyoxylate. Glyoxylate, a product of either glycolate oxidase or isocitrate lyase, can be converted to oxalate. Malonate is accumulated at high concentrations in legume plants. Organic acids play a role in plants in providing redox equilibrium, supporting ionic gradients on membranes, and acidification of the extracellular medium. PMID:27471516

  12. Granal stacking of thylakoid membranes in higher plant chloroplasts: the physicochemical forces at work and the functional consequences that ensue.

    PubMed

    Chow, Wah Soon; Kim, Eun-Ha; Horton, Peter; Anderson, Jan M

    2005-12-01

    The formation of grana in chloroplasts of higher plants is examined in terms of the subtle interplay of physicochemical forces of attraction and repulsion. The attractive forces between two adjacent membranes comprise (1) van der Waals attraction that depends on the abundance and type of atoms in each membrane, on the distance between the membranes and on the dielectric constant, (2) depletion attraction that generates local order by granal stacking at the expense of greater disorder (i.e. entropy) in the stroma, and (3) an electrostatic attraction of opposite charges located on adjacent membranes. The repulsive forces comprise (1) electrostatic repulsion due to the net negative charge on the outer surface of thylakoid membranes, (2) hydration repulsion that operates at small separations between thylakoid membranes due to layers of bound water molecules, and (3) steric hindrance due to bulky protrusions of Photosystem I (PSI) and ATP synthase into the stroma. In addition, specific interactions may occur, but they await experimental demonstration. Although grana are not essential for photosynthesis, they are ubiquitous in higher plants. Grana may have been selected during evolution for the functional advantages that they confer on higher plants. The functional consequences of grana stacking include (1) enhancement of light capture through a vastly increased area-to-volume ratio and connectivity of several PSIIs with large functional antenna size, (2) the ability to control the lateral separation of PSI from PSII and, therefore, the balanced distribution of excitation energy between two photosystems working in series, (3) the reversible fine-tuning of energy distribution between the photosystems by State 1-State 2 transitions, (4) the ability to regulate light-harvesting via controlled thermal dissipation of excess excitation energy, detected as non-photochemical quenching, (5) dynamic flexibility in the light reactions mediated by a granal structure in response to

  13. Long Distance Runners Present Upregulated Sweating Responses than Sedentary Counterparts

    PubMed Central

    Lee, Jeong-Beom; Kim, Tae-Wook; Min, Young-Ki; Yang, Hun-Mo

    2014-01-01

    Relatively few studies have investigated peripheral sweating mechanisms of long-distance runners. The aim of this study was to compare peripheral sweating mechanisms in male long-distance runners, and sedentary counterparts. Thirty six subjects, including 20 sedentary controls and 16 long-distance runners (with 7–12 years of athletic training, average 9.2±2.1 years) were observed. Quantitative sudomotor axon reflex testing (QSART) with iontophoresis (2 mA for 5 min) and 10% acetylcholine (ACh) were performed to determine axon reflex-mediated and directly activated (DIR, muscarinic receptor) sweating. Sweat onset time, sweat rate, number of activated sweat glands, sweat output per gland and skin temperature were measured at rest while maximum oxygen uptake (VO2max) were measured during maximal cycling. Sweat rate, activated sweat glands, sweat output per gland, skin temperature and VO2max were significantly higher in the trained runners than in the sedentary controls. Sweat onset time was significantly shorter for the runners. In the group of long-distance runners, significant correlations were found between VO2max and sweat onset time (r2 = 0.543, P<0.01, n = 16), DIR sweat rate (r2 = 0.584, P<0.001, n = 16), sweat output per gland (r2 = 0.539, P<0.01, n = 16). There was no correlation between VO2max and activated sweat glands. These findings suggest that habitual long-distance running results in upregulation of the peripheral sweating mechanisms in humans. Additional research is needed to determine the molecular mechanism underlying these changes. These findings complement the existing sweating data in long-distance runners. PMID:24709823

  14. Isolation of photosystem II-enriched membranes and the oxygen-evolving complex subunit proteins from higher plants.

    PubMed

    Yamamoto, Yasusi; Leng, Jing; Shen, Jian-Ren

    2011-01-01

    We describe methods to isolate highly active oxygen-evolving photosystem II (PSII) membranes and core complexes from higher plants, and to purify subunits of the oxygen-evolving complex (OEC). The membrane samples used as the material for various in vitro studies of PSII are prepared by solubilizing thylakoid membranes with the nonionic detergent Triton X-100, and the core complexes are prepared by further solubilization of the PSII membranes with n-dodecyl-β-D-maltoside (β-DDM). The OEC subunit proteins are dissociated from the PSII-enriched membranes by alkaline or salt treatment, and are then purified by ion-exchange chromatography using an automated high performance liquid chromatography system. PMID:20960116

  15. New insights on the organization and regulation of the fatty acid biosynthetic network in the model higher plant Arabidopsis thaliana.

    PubMed

    Troncoso-Ponce, Manuel Adrián; Nikovics, Krisztina; Marchive, Chloé; Lepiniec, Loïc; Baud, Sébastien

    2016-01-01

    In the plastids of plant cells, fatty acid (FA) production is a central biosynthetic process. It provides acyl chains for the formation of a variety of acyl lipids fulfilling different biological functions ranging from membrane synthesis to signaling or carbon and energy storage. The biochemical pathway leading to the synthesis of FA has been described for a long time. Over the last 15 years, and after the genome of the model higher plant Arabidopsis thaliana has been sequenced, the scientific community has deployed approaches of functional genomics to identify the actors comprising this pathway. One of the puzzling aspects of the emerging molecular biology of FA synthesis resided in the occurrence of multigene families encoding most enzymes of the pathway. Studies carried out to investigate these families led to the conclusion that most members have acquired non-redundant roles in planta. This is usually the consequence of divergent expression patterns of these isogenes and/or of different substrate specificities of the isoforms they encode. Nevertheless, much remains to be elucidated regarding the molecular bases underpinning these specificities. Protein biochemistry together with emerging quantitative proteomic technologies have then led to a better understanding of the structure of the network, which is composed of multiprotein complexes organized within the stromal compartment of plastids: whereas growing evidence suggests that the early steps of the pathway might be associated to the inner envelope membrane, several late enzymes might be localized next to the thylakoids. The question of the existence of a large integrated protein assembly channeling substrates through the whole pathway that would span the stroma remains uncertain. Finally, recent discoveries regarding the post-translational regulation of the pathway open new research horizons and may guide the development of relevant biotechnological strategies aimed at monitoring FA production in plant

  16. A Neogene Higher Plant N-Alkane Carbon and Hydrogen Isotope Record From the Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Tipple, B. J.; Pagani, M.

    2006-12-01

    Water availability and a plant's capacity to cope with water stress are expressed in carbon and hydrogen isotopic compositions of leaf waxes. Therefore, coupled sedimentary n-alkane δ13C and δD isotope records provide unique continental-scale information about the paleo-hydrological cycle and its influence on biology over long time scales. In this study, we assess the relationship between Neogene North American climate and floral change, particularly C4 grass expansion, by establishing δ13C and δD records of higher-plant leaf wax n-alkanes from Gulf of Mexico sediments (DSDP site 94). Changes in the hydrogen isotope composition of leaf water can be driven by changes in evaporation/evapotranspiration or changes in the evaporative source from which precipitation derives. However, for this study changes in moisture source are unlikely because these sediments located in Gulf of Mexico likely received the majority of precipitation from the Gulf of Mexico itself over the time interval studied. In general, δ13C and δD values shift in concert, with the most positive δ13C and δD values occurring near the Epoch boundaries. N-alkane δ13C values reflect factors other than water stress alone, including the isotopic composition of atmospheric CO2, plant community, and atmospheric pCO2. Notably, 13C enrichment occurring near the Oligocene/Miocene boundary potentially reflects the rapid decrease in pCO2 at this time. In addition, between 4.5 and 5.5 Ma, n-alkane δ13C values trend more negative as δD becomes increasingly D-enriched, indicative of increased evaporation. Given that contemporaneous North American terrestrial isotope (Passey et al., 2002) and equatorial Atlantic marine (Wagner, 2002) records show similar trends, it appears that major changes in the hydrological cycle took place at this time.

  17. Compositional equivalency of RNAi-mediated virus-resistant transgenic soybean and its nontransgenic counterpart.

    PubMed

    Zhang, Xiuchun; Zhao, Pingjuan; Wu, Kunxin; Zhang, Yuliang; Peng, Ming; Liu, Zhixin

    2014-05-14

    RNA silencing or RNA interference (RNAi), which is triggered by double-stranded RNA (dsRNA), is an evolutionarily conserved process that is active in a wide variety of eukaryotic organisms. Engineering plants with hairpin construct in which the viral gene is arranged in inverted repeats (IR) renders plants resistant to plant virus infection. However, there is no report on whether biologically important changes occurred by the insertion of IR, which confer transgenic plants virus resistance. In the present study, the compositions of virus-resistant transgenic soybean seeds developed by insertion of three short IRs, each containing the specific, highly conserved sequences derived from one virus, were compared with those of nontransgenic counterparts by applying the principle of substantial equivalence to determine whether significant undesirable biological changes occurred by IR insertion. The results revealed that the nutrient components as well as antinutrient contents of these virus-resistant soybean lines are substantially equivalent to those of the nontransgenic counterparts, and the majority of the measured amounts of nutritional components and antinutrient contents are well within the range of values reported for other commercial soybean lines. The results imply that no biologically important changes occurred by the insertion of IRs in the RNAi-mediated virus-resistant transgenic soybeans. The results can serve as baseline information for developing RNAi-mediated transgenic soybean cultivars or other crops with broader spectrum virus resistance. PMID:24754373

  18. Slow molecular evolution in 18S rDNA, rbcL and nad5 genes of mosses compared with higher plants.

    PubMed

    Stenøien, H K

    2008-03-01

    The evolutionary potential of bryophytes (mosses, liverworts and hornworts) has been debated for decades. Fossil record and biogeographical distribution patterns suggest very slow morphological evolution and the retainment of several ancient traits since the split with vascular plants some 450 million years ago. Many have argued that bryophytes may evolve as rapidly as higher plants on the molecular level, but this hypothesis has not been tested so far. Here, it is shown that mosses have experienced significantly lower rates of molecular evolution than higher plants within 18S rDNA (nuclear), rbcL (chloroplast) and nad5 (mitochondrial) genes. Mosses are on an average evolving 2-3 times slower than ferns, gymnosperms and angiosperms; and also green algae seem to be evolving faster than nonvascular plants. These results support the observation of a general correlation between morphological and molecular evolutionary rates in plants and also show that mosses are 'evolutionary sphinxes' regarding both morphological and molecular evolutionary potential. PMID:18205784

  19. Reevaluating the free-ion activity model of trace metal toxicity toward higher plants: experimental evidence with copper and zinc.

    PubMed

    Parker, D R; Pedler, J F; Ahnstrom, Z A; Resketo, M

    2001-04-01

    Across a diverse spectrum of organisms, the absorption and toxicity of trace elements are usually correlated with the activity of the free metal ion, but reported exceptions to this generalization are increasing. For the first time, we tested the validity of the free-ion activity model (FIAM) in the case of terrestrial plants and organic acids that may be abundant in the soil solution and rhizosphere. Short-term (48-h) root elongation of wheat (Triticum aestitvum L.) in a simple medium (2 mM CaCl2, pH 6.0) was used to probe the toxicity of Cu and Zn in the presence of malonate, malate, and citrate. Precautions were taken to prevent biodegradation of the organic acids, and its absence was confirmed by ion chromatography. Copper speciation was verified using a Cu-selective ion electrode, and published stability constants were modified to improve agreement between measured and calculated Cu2+ activities. With additions of both malonate and malate, Cu toxicity was alleviated but not to the extent predicted by the FIAM; the Cu-ligand complexes seemingly contributed to the toxicity. No such departures were observed with citrate and Cu nor with any of the three ligands in combination with Zn. Thus, exceptions to the FIAM occur with higher plants as well as with aquatic biota but do not seem to occur in a predictable or systematic fashion with respect to metal or organic acid under investigation. Several possible explanations for the observed departures from the FIAM are discussed, including the possibility of accidental cotransport of metal and ligand into the cytoplasm. PMID:11345467

  20. The optical counterpart to XMMU J004855.5-734946

    NASA Astrophysics Data System (ADS)

    Coe, M. J.; McBride, V.; Haberl, F.; Bird, A.; Udalski, A.

    2016-06-01

    The source, XMMU J004855.5-734946, reported to be currently exhibiting an X-ray outburst in ATel #9197, has an optical counterpart in the OGLE IV database, SMC720.11 13342, proposed by McBride et al (2016, in prep).

  1. Reading, Writing, and Psycholinguistics: An Integrated Approach Using Joyce's "Counterparts."

    ERIC Educational Resources Information Center

    Buckler, Patricia Prandini

    1985-01-01

    Explains how, in a second-semester freshman composition course, Louise Rosenblatt's model for the process of reading literature was used with James Moffett's concept of the process of writing to create a linked series of reading-writing exercises based on Joyce's "Counterparts." (FL)

  2. Variability of Optical Counterparts in the Chandra Galactic Bulge Survey

    NASA Astrophysics Data System (ADS)

    Britt, C. T.; Hynes, R. I.; Johnson, C. B.; Baldwin, A.; Jonker, P. G.; Nelemans, G.; Torres, M. A. P.; Maccarone, T.; Steeghs, D.; Greiss, S.; Heinke, C.; Bassa, C. G.; Collazzi, A.; Villar, A.; Gabb, M.; Gossen, L.

    2014-09-01

    We present optical light curves of variable stars consistent with the positions of X-ray sources identified with the Chandra X-ray Observatory for the Chandra Galactic Bulge Survey (GBS). Using data from the Mosaic-II instrument on the Blanco 4 m Telescope at CTIO, we gathered time-resolved photometric data on timescales from ~2 hr to 8 days over the 3/4 of the X-ray survey containing sources from the initial GBS catalog. Among the light curve morphologies we identify are flickering in interacting binaries, eclipsing sources, dwarf nova outbursts, ellipsoidal variations, long period variables, spotted stars, and flare stars. Eighty-seven percent of X-ray sources have at least one potential optical counterpart. Twenty-seven percent of these candidate counterparts are detectably variable; a much greater fraction than expected for randomly selected field stars, which suggests that most of these variables are real counterparts. We discuss individual sources of interest, provide variability information on candidate counterparts, and discuss the characteristics of the variable population.

  3. The HIPASS catalogue - III. Optical counterparts and isolated dark galaxies

    NASA Astrophysics Data System (ADS)

    Doyle, M. T.; Drinkwater, M. J.; Rohde, D. J.; Pimbblet, K. A.; Read, M.; Meyer, M. J.; Zwaan, M. A.; Ryan-Weber, E.; Stevens, J.; Koribalski, B. S.; Webster, R. L.; Staveley-Smith, L.; Barnes, D. G.; Howlett, M.; Kilborn, V. A.; Waugh, M.; Pierce, M. J.; Bhathal, R.; de Blok, W. J. G.; Disney, M. J.; Ekers, R. D.; Freeman, K. C.; Garcia, D. A.; Gibson, B. K.; Harnett, J.; Henning, P. A.; Jerjen, H.; Kesteven, M. J.; Knezek, P. M.; Mader, S.; Marquarding, M.; Minchin, R. F.; O'Brien, J.; Oosterloo, T.; Price, R. M.; Putman, M. E.; Ryder, S. D.; Sadler, E. M.; Stewart, I. M.; Stootman, F.; Wright, A. E.

    2005-07-01

    We present the largest catalogue to date of optical counterparts for HI radio-selected galaxies, HOPCAT. Of the 4315 HI radio-detected sources from the HI Parkes All Sky Survey (HIPASS) catalogue, we find optical counterparts for 3618 (84 per cent) galaxies. Of these, 1798 (42 per cent) have confirmed optical velocities and 848 (20 per cent) are single matches without confirmed velocities. Some galaxy matches are members of galaxy groups. From these multiple galaxy matches, 714 (16 per cent) have confirmed optical velocities and a further 258 (6 per cent) galaxies are without confirmed velocities. For 481 (11 per cent), multiple galaxies are present but no single optical counterpart can be chosen and 216 (5 per cent) have no obvious optical galaxy present. Most of these `blank fields' are in crowded fields along the Galactic plane or have high extinctions. Isolated `dark galaxy' candidates are investigated using an extinction cut of ABj < 1mag and the blank-fields category. Of the 3692 galaxies with an ABj extinction <1mag, only 13 are also blank fields. Of these, 12 are eliminated either with follow-up Parkes observations or are in crowded fields. The remaining one has a low surface brightness optical counterpart. Hence, no isolated optically dark galaxies have been found within the limits of the HIPASS survey.

  4. VARIABILITY OF OPTICAL COUNTERPARTS IN THE CHANDRA GALACTIC BULGE SURVEY

    SciTech Connect

    Britt, C. T.; Hynes, R. I.; Johnson, C. B.; Baldwin, A.; Collazzi, A.; Gossen, L.; Jonker, P. G.; Torres, M. A. P.; Nelemans, G.; Maccarone, T.; Steeghs, D.; Greiss, S.; Heinke, C.; Bassa, C. G.; Villar, A.; Gabb, M.

    2014-09-01

    We present optical light curves of variable stars consistent with the positions of X-ray sources identified with the Chandra X-ray Observatory for the Chandra Galactic Bulge Survey (GBS). Using data from the Mosaic-II instrument on the Blanco 4 m Telescope at CTIO, we gathered time-resolved photometric data on timescales from ∼2 hr to 8 days over the 3/4 of the X-ray survey containing sources from the initial GBS catalog. Among the light curve morphologies we identify are flickering in interacting binaries, eclipsing sources, dwarf nova outbursts, ellipsoidal variations, long period variables, spotted stars, and flare stars. Eighty-seven percent of X-ray sources have at least one potential optical counterpart. Twenty-seven percent of these candidate counterparts are detectably variable; a much greater fraction than expected for randomly selected field stars, which suggests that most of these variables are real counterparts. We discuss individual sources of interest, provide variability information on candidate counterparts, and discuss the characteristics of the variable population.

  5. [Impacts of human disturbance on the species composition of higher plants in the wetlands around Dianchi Lake, Yunnan Province of Southwest China].

    PubMed

    Xiang, Xi-Xi; Wu, Zhao-Lu; Luo, Kang; Ding, Hong-Bo; Zhang, Hai-Yan

    2013-09-01

    Introducing higher plants to build semi-natural wetland ecosystem is one of the key approaches to restore the wetlands and lakes that suffered from serious pollution and destruction. Based on the investigation data from 128 quadrats at 26 sampling sites in the wetlands around Dianchi Lake in December 2011-October 2012, and in combining with the references published in the 1960s, this paper discussed the impacts of human activities on the species composition of higher plants in the wetlands around the Lake. In 2012, there were 299 species of 88 families in the wetlands, of which, 181 species were native species, and 118 species were alien ones (including 32 invasive species). Of the 42 species of hydrophytes in the total species, 13 species were alien ones (including 2 invasive species). In comparing with the species data recorded in the 1960s, 232 plants were newly recorded and 43 species disappeared in 2012. Aquatic plants changed obviously. The decreased species were 2 submerged plants, 2 floating plants, and 5 floating leaved plants, and the increased species were 8 emergent plants. Fourteen community types were identified by cluster analysis, of which, the main communities were those dominated by alien species including Pistia stratiotes and Alternanthera philoxeroides. As compared with the data in the 1960s, the plant communities dominated by native species such as Ottelia acuminate and Vallisneria natans were not found presently. Therefore, in the practice of introducing higher plants to restore the degraded wetlands and lakes, it would be necessary to scientifically and appropriately select and blend plant species to avoid the wetland degradation by human activities. PMID:24417101

  6. Results of the first stage (2002-2009) of investigation of higher plants onboard RS ISS, as an element of future closed Life Support Systems

    NASA Astrophysics Data System (ADS)

    Sychev, Vladimir; Levinskikh, Margarita; Podolsky, Igor; Bingham, Gail; Novikova, Nataliya; Sugimoto, Manabu

    A key task for biomedical human support in long-term manned space expeditions is the develop-ment of the Life Support System (LSS). It is expected that in the first continuous interplanetary expeditions LSS of only a few biological elements of the LSS, such as higher plants will be in-cluded. Therefore, investigations of growth and development of higher plants for consideration in the LSS are of high importance. In a period from October, 2002 to December 2009, 15 ex-periments on cultivation of different plants, including two genetically marked species of dwarf peas, a leaf vegetable strain of Mizuna, radish, barley and wheat were conducted in space greenhouse "LADA" onboard Russian Segment (RS) of International Space Station (ISS). The experiments resulted in the conclusion that the properties of growth and development of plants grown in space greenhouse "LADA" were unaffected by spaceflight conditions. In experiments conducted in a period from 2003 to 2005, it was shown for the first time that pea plants pre-serve reproductive functions, forming viable seeds during at least four continuous full cycles of ontogenesis ("seed to seed") under spaceflight conditions. No changes were found in the genetic apparatus of the pea plants in the four "space" generations. Since 2005, there have been routine collections of microbiological samples from the surfaces of the plants grown on-board in "LADA" greenhouse. Analysis has shown that the properties of contamination of the plants grown aboard by microorganism contain no abnormal patterns. Since 2008, the plants cultivated in "LADA" greenhouse have been frozen onboard RS ISS in the MELFI refrigerator and transferred to the Earth for further investigations. Investigations of Mizuna plants grown and frozen onboard of ISS, showed no differences between "ground control" and "space" plants in chemical and biochemical properties. There also no stress-response was found in kashinriki strain barley planted and frozen onboard ISS.

  7. Impacts of UV radiation and photomodification on the toxicity of PAHs to the higher plant Lemna gibba (duckweed)

    SciTech Connect

    Xiaodong Huang; Dixon, D.G.; Greenberg, B.M. . Dept. of Biology)

    1993-06-01

    The toxicity of polycyclic aromatic hydrocarbons (PAHs) can be enhanced by both biotic and abiotic processes. This is exemplified by light, which, by virtue of the extensive [pi]-orbital systems of PAHs, can be a major factor in PAH toxicity. Light activation of PAHs is known to occur via photosensitization reactions and potentially by photomodification of the chemicals to more toxic species. To examine the modes of PAH action in the light and determine if the photomodified compounds are hazardous, the authors investigated the photoinduced toxicity of anthracene, phenanthrene and benzo[a]pyrene to the aquatic higher plant Lemna gibba (a duckweed). Toxicity end points were inhibition of growth and extent of chlorosis. Light did indeed activated the phytotoxicity of PAHs, with UV radiation more effective than visible light. Dose-response curves based on chemical concentration and light intensity revealed the order of phytotoxic strength to be anthracene > phenanthrene > benzo[a]pyrene. To explore whether photomodified PAHs were contributing to toxicity, the chemicals were irradiated before toxicity testing. The rates of photomodification of the three PAHs were rapid, and the relative velocities were coincident with the order of toxic strength. Furthermore, the photomodified PAHs were more hazardous to Lemna than the intact compounds. Because interpretations of the potential impacts of PAHs in the environment are based mostly on measurements of the structurally intact chemicals, the severity of PAH hazards is possibly underestimated.

  8. Evidence for a universal pathway of abscisic acid biosynthesis in higher plants from sup 18 O incorporation patterns

    SciTech Connect

    Zeevaart, J.A.D.; Heath, T.G.; Gage, D.A. )

    1989-12-01

    Previous labeling studies of abscisic acid (ABA) with {sup 18}O{sub 2} have been mainly conducted with water-stressed leaves. In this study, {sup 18}O incorporation into ABA of stressed leaves of various species was compared with {sup 18}O labeling of ABA of turgid leaves and of fruit tissue in different stages of ripening. In stressed leaves of all six species investigated, avocado (Persea americana), barley (Hordeum vulgare), bean (Phaseolus vulgaris), cocklebur (Xanthium strumarium), spinach (Spinacia oleracea), and tobacco (Nicotiana tabacum), {sup 18}O was most abundant in the carboxyl group, whereas incorporation of a second and third {sup 18}O in the oxygen atoms on the ring of ABA was much less prominent after 24 h in {sup 18}O{sub 2}. ABA from turgid bean leaves showed significant {sup 18}O incorporation, again with highest {sup 18}O enrichment in the carboxyl group. On the basis of {sup 18}O-labeling patterns observed in ABA from different tissues it is concluded that, despite variations in precusor pool sizes and intermediate turnover rates, there is a universal pathway of ABA biosynthesis in higher plants which involves cleavage of a larger precursor molecule, presumably an oxygenated carotenoid.

  9. Roles of FtsH protease in choloroplast biogensis and protection of photosystems from high temperatures stress in higher plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    AtFtsH11 protease gene is essential for Arabidopsis plant to survive at moderate heat stress. Under high and normal light at 21ºC, ftsh11 mutants were indistinguishable from wild type plants in photosynthesis capability and in overall growth. However, mutant plants display a host of dramatic change...

  10. State Assessments: Does a Charter School Truly Demonstrate Higher Proficiency than Its Public Counterpart?

    ERIC Educational Resources Information Center

    Kindzierski, Corinne M.; Mhammed, Ali Ait Si; Wallace, Nancy; Lesh, Christina

    2013-01-01

    This project compared annual mandated assessment results for an urban charter school, two comparable urban schools and the encompassing urban district. Scores in grades three through eight in the target school were analyzed to determine the percentage of students scoring at proficiency levels three and four (scores of one and two are considered…

  11. Identifying Electromagnetic Counterparts to Gravitational Wave Triggers With DECam

    NASA Astrophysics Data System (ADS)

    Cowperthwaite, Philip

    2016-03-01

    Identifying the electromagnetic counterpart to a gravitational wave (GW) event is one of the great observational challenges in modern astronomy. We report on our work to overcome this challenge by investigating the theoretical and practical issues associated with optical follow-up of a GW event. This includes a systematic study of the potential contaminant population and their impact on counterpart detectability in simulated observations. Additionally, we utilize data taken with the Dark Energy Camera (DECam) on the Blanco 4-m telescope at CTIO. These data serve as a mock follow-up to a GW event and assist in the characterization of contamination not captured in simulations. P.S.C. is grateful for support provided by the NSF through the Graduate Research Fellowship Program, Grant DGE1144152.

  12. The Optical Counterpart of M101 ULX-1

    NASA Technical Reports Server (NTRS)

    Kuntz, K. D.; Gruendi, Robert A.; Chu, You-Hua; Chen, C.-H. Rosie; Still, Martin; Mukai, Koji; Musuotzky, Richard F.

    2004-01-01

    We have identified the optical counterpart of the Ultra-Luminous X-ray source Ml0l ULX-1 (CX- OKM101 J140332.74+542102), by comparing HST ACS images with Chandra ACIS-S images. The optical counterpart has V= 23.75 and colours consistent with those for a mid-B supergiant. Archival WFPC2 observations show that the source brightness is constant to within approximately 0.1 mag. The physical association of this source with the ULX is confirmed by Gemini GMOS spectroscopic observations which show spatially unresolved He II lambda4686 and He I lambda5876 emission. These results suggest that M10l ULX-1 is a HMXB but deep spectroscopic monitoring observations are needed to determine the detailed properties of this system.

  13. OPTICAL COUNTERPARTS OF THE NEAREST ULTRALUMINOUS X-RAY SOURCES

    SciTech Connect

    Gladstone, Jeanette C.; Heinke, Craig O.; Cartwright, Taylor F.; Copperwheat, Chris; Roberts, Timothy P.; Levan, Andrew J.; Goad, Mike R.

    2013-06-01

    We present a photometric survey of the optical counterparts of ultraluminous X-ray sources (ULXs) observed with the Hubble Space Telescope (HST) in nearby ({approx}<5 Mpc) galaxies. Of the 33 ULXs with HST and Chandra data, 9 have no visible counterpart, placing limits on their M{sub V} of {approx} -4 to -9, enabling us to rule out O-type companions in 4 cases. The refined positions of two ULXs place them in the nucleus of their host galaxy. They are removed from our sample. Of the 22 remaining ULXs, 13 have one possible optical counterpart, while multiple are visible within the error regions of other ULXs. By calculating the number of chance coincidences, we estimate that 13 {+-} 5 are the true counterparts. We attempt to constrain the nature of the companions by fitting the spectral energy distribution and M{sub V} to obtain candidate spectral types. We can rule out O-type companions in 20 cases, while we find that one ULX (NGC 253 ULX2) excludes all OB-type companions. Fitting with X-ray irradiated models provides constraints on the donor star mass and radius. For seven ULXs, we are able to impose inclination-dependent upper and/or lower limits on the black holes' mass, if the extinction to the assumed companion star is not larger than the Galactic column. These are NGC 55 ULX1, NGC 253 ULX1, NGC 253 ULX2, NGC 253 XMM6, Ho IX X-1, IC342 X-1, and NGC 5204 X-1. This suggests that 10 ULXs do not have O companions, while none of the 18 fitted rule out B-type companions.

  14. "Biliary Diseases with Pancreatic Counterparts": Cross-sectional Imaging Findings.

    PubMed

    Katabathina, Venkata S; Flaherty, Erin M; Dasyam, Anil K; Menias, Christine O; Riddle, Nicole D; Lath, Narayan; Kozaka, Kazuto; Matsui, Osamu; Nakanuma, Yasuni; Prasad, Srinivasa R

    2016-01-01

    On the basis of the similarities in the histopathologic findings and the clinical-biologic behaviors of select biliary and pancreatic conditions, a new disease concept, "biliary diseases with pancreatic counterparts," has been proposed. Both nonneoplastic and neoplastic pathologic conditions of the biliary tract have their counterparts in the pancreas. Immunoglobulin G4 (IgG4)-related sclerosing cholangitis is the biliary manifestation of IgG4-related sclerosing disease, and type 1 autoimmune pancreatitis is its pancreatic counterpart. People with chronic alcoholism can develop peribiliary cysts and fibrosis as well as pancreatic fibrosis and chronic pancreatitis simultaneously. Pancreatic ductal adenocarcinoma, intraductal papillary mucinous neoplasm, and mucinous cystic neoplasm are considered pancreatic counterparts for the biliary neoplasms of extrahepatic cholangiocarcinoma, intraductal papillary neoplasm of the biliary tract, and hepatic mucinous cystic neoplasm, respectively. The anatomic proximity of the biliary tract and the pancreas, the nearly simultaneous development of both organs from the endoderm of the foregut, and the presence of pancreatic exocrine acini within the peribiliary glands surrounding the extrahepatic bile ducts are suggested as causative factors for these similarities. Interestingly, these diseases show "nearly" identical findings at cross-sectional imaging, an observation that further supports this new disease concept. New information obtained with regard to biliary diseases can be used for evaluation of pancreatic abnormalities, and vice versa. In addition, combined genetic and molecular studies may be performed to develop novel therapeutic targets. For both biliary and pancreatic diseases, imaging plays a pivotal role in initial diagnosis, evaluation of treatment response, efficacy testing of novel drugs, and long-term surveillance. PMID:26824512

  15. Localization of small heat shock proteins to the higher plant endomembrane system. [Low-molecular-weight heat shock proteins

    SciTech Connect

    Helm, K.W.; Vierling, E. ); LaFayette, P.R.; Nagao, R.T.; Key, J.L. )

    1993-01-01

    Most eukaryotic cells respond to high temperature and other stresses with the production of heat shock proteins, which aid in cell survival. There are four major classes of heat shock proteins HSP90, HSP70, HSP60 and low-molecular weight HSP. The data from this research indicate that members of the low-molecular weight heat shock proteins are most likely resident endoplasmic reticulum (ER) proteins and may be similar in function to related low-molecular weight heat shock proteins in the cytoplasm. The low-molecular weight heat shock proteins, the HSP90 and the HSP70 all appear to localize to the endoplasmic reticulum. Since the ER-localized low-molecular weight heat shock proteins are physically separated from their counterparts in other cell compartments, investigations of the ER-localized heat shock proteins provides a simplified model system for determining the functions of low-molecular weight heat shock proteins in eukaryotes.

  16. The Search for Gravitational Wave EM Counterparts with Swift

    NASA Astrophysics Data System (ADS)

    Kennea, Jamie; Evans, Phil; Swift GW follow-up Team

    2016-04-01

    We present the plan to search for electromagnetic counterparts of Gravitational Waves (GWs) discovered during the current and upcoming runs of the LIGO and Virgo detectors. As we enter a period where the sensitivity of the current generation of GW detectors approaches a high probability of the first detection of a real GW signal, confirmation of the reality of these triggers will be greatly improved if an EM counterpart can be found. Swift’s ability to rapidly respond to high priority target-of-opportunity observations, it’s multi-wavelength capabilities and low overhead observing make it a seemingly ideal follow-up facility. However comparing the size of the expected GW error regions with the fields of view of the Swift XRT and UVOT telescopes, we find that covering the large GW error regions would require a unreasonably large number of pointings. We present our method of meeting this challenge, by both reducing the problem using Galaxy targeting, and by operating Swift in an entirely new way in order to cover the still large number of fields needed to chase down the EM counterpart before it disappears.

  17. Leaves of higher plants as biomonitors of radionuclides (137Cs, 40K, 210Pb and 7Be) in urban air.

    PubMed

    Todorović, Dragana; Popović, Dragana; Ajtić, Jelena; Nikolić, Jelena

    2013-01-01

    Leaves of linden (Tilia tomentosa L. and Tilia cordata Mill.) and horse chestnut (Aesculus hippocastanum L.) were analysed as biomonitors of radionuclides in urban air. Samples of soils, leaves and aerosols were collected in Belgrade, Serbia. Activities of (137)Cs, (40)K, (210)Pb and (7)Be in the samples were measured on an HPGe detector by standard gamma spectrometry. "Soil-to-leaves" transfer factors were calculated. Student's t test and linear Pearson correlation coefficients were used for statistical analysis. Differences in local conditions at the sampling sites were not significant, and the mechanisms of the radionuclides' accumulation in both plant species are similar. Ceasium-137 was detected in some of the leaf samples only. Transfer factors for (137)Cs and (40)K were (0.03-0.08) and 1.3, respectively. The concentrations of (210)Pb and (7)Be in leaves were higher in autumn than in spring, and there were some similarities in their seasonal patterns in leaves and in air. Weak to medium correlation was obtained for the (210)Pb and (7)Be activities in leaves and aerosols. Large positive correlation was obtained for the (210)Pb activities in linden leaves and the mean activity in aerosols for the preceding months. Different primary modes of radionuclides accumulation in leaves were observed. Since large positive correlation was obtained for the (210)Pb activity in linden leaves and the mean in aerosols for the preceding months, mature linden leaves could be used as biomonitors of recent (210)Pb activity in air. PMID:22562351

  18. Polyamine formation by arginine decarboxylase as a transducer of hormonal, environmental and stress stimuli in higher plants

    NASA Technical Reports Server (NTRS)

    Galston, A. W.; Flores, H. E.; Kaur-Sawhney, R.

    1982-01-01

    Recent evidence implicates polyamines including putrescine in the regulation of such diverse plant processes as cell division, embryogenesis and senescence. We find that the enzyme arginine decarboxylase, which controls the rate of putrescine formation in some plant systems, is activated by light acting through P(r) phytochrome as a receptor, by the plant hormone gibberellic acid, by osmotic shock and by other stress stimuli. We therefore propose arginine decarboxylase as a possible transducer of the various initially received tropistic stimuli in plants. The putrescine formed could act by affecting cytoskeletal components.

  19. INVESTIGATING THE OPTICAL COUNTERPART CANDIDATES OF FOUR INTEGRAL SOURCES LOCALIZED WITH CHANDRA

    SciTech Connect

    Oezbey Arabac Latin-Small-Letter-Dotless-I , Mehtap; Kalemci, Emrah; Tomsick, John A.; Bodaghee, Arash; Halpern, Jules; Chaty, Sylvain; Rodriguez, Jerome

    2012-12-10

    We report on the optical spectroscopic follow-up observations of the candidate counterparts to four INTEGRAL sources: IGR J04069+5042, IGR J06552-1146, IGR J21188+4901, and IGR J22014+6034. The candidate counterparts were determined with Chandra, and the optical observations were performed with 1.5 m RTT-150 telescope (TUeBITAK National Observatory, Antalya, Turkey) and 2.4 m Hiltner Telescope (MDM Observatory, Kitt Peak, Arizona). Our spectroscopic results show that one of the two candidates of IGR J04069+5042 and the one observed for IGR J06552-1146 could be active late-type stars in RS CVn systems. However, according to the likelihood analysis based on Chandra and INTEGRAL, two optically weaker sources in the INTEGRAL error circle of IGR J06552-1146 have higher probabilities to be the actual counterpart. The candidate counterparts of IGR J21188+4901 are classified as an active M-type star and a late-type star. Among the optical spectra of four candidates of IGR J22014+6034, two show H{alpha} emission lines, one is a late-type star, and the other is an M type. The likelihood analysis favors a candidate with no distinguishing features in the optical spectrum. Two of the candidates classified as M-type dwarfs, are similar to some IGR candidates claimed to be symbiotic stars. However, some of the prominent features of symbiotic systems are missing in our spectra, and their NIR colors are not consistent with those expected for giants. We consider the IR colors of all IGR candidates claimed to be symbiotic systems and find that low-resolution optical spectrum may not be enough for conclusive identification.

  20. Searching for Optical Counterparts to Ultra-compact High Velocity Clouds: Possible Detection of a Counterpart to AGC 198606

    NASA Astrophysics Data System (ADS)

    Janesh, William; Rhode, Katherine L.; Salzer, John J.; Janowiecki, Steven; Adams, Elizabeth A. K.; Haynes, Martha P.; Giovanelli, Riccardo; Cannon, John M.; Muñoz, Ricardo R.

    2015-09-01

    We report initial results from a campaign to obtain optical imaging of Ultra Compact High Velocity Clouds (UCHVCs) discovered by the Arecibo Legacy Fast ALFA (ALFALFA) Hi survey. UCHVCs have properties consistent with their being low-mass dwarf galaxies in the Local Volume, but do not have identified optical counterparts. We are using the WIYN 3.5 m telescope to image these objects and search for an associated stellar population. Here we present our observational strategy and method for searching for resolved stellar counterparts to the UCHVCs. We combine careful photometry, a color-magnitude filter, and spatial smoothing techniques to search for stellar overdensities in the g- and i-band images. We also run statistical tests to quantify the likelihood that detected overdensities are real and not chance superpositions of sources. We demonstrate the method by applying it to WIYN imaging of two objects: Leo P, a UCHVC discovered by ALFALFA and shown to be a star-forming dwarf galaxy in the Local Volume and AGC 198606, an ALFALFA source near in position and velocity to the Local Group dwarf galaxy Leo T. Applying the search method to the Leo P data yields an unambiguous detection (>99% confidence) of the galaxy’s stellar population. Applying the method to the AGC 198606 imaging yields a possible detection (92% confidence) of an optical counterpart located ˜2.5 arcmin from the centroid of AGC 198606's Hi distribution and within the Hi disk. We estimate a distance to the stellar counterpart of 373-393 kpc, an absolute magnitude Mi = -4.67 ± 0.09, and an Hi-to-stellar mass ratio of ˜45-110.

  1. Searching for Optical Counterparts to Ultra-compact High Velocity Clouds: Possible Detection of a Counterpart to AGC 198606

    NASA Astrophysics Data System (ADS)

    Janesh, William; Rhode, Katherine L.; Salzer, John J.; Janowiecki, Steven; Adams, Elizabeth A. K.; Haynes, Martha P.; Giovanelli, Riccardo; Cannon, John M.; Muñoz, Ricardo R.

    2015-09-01

    We report initial results from a campaign to obtain optical imaging of Ultra Compact High Velocity Clouds (UCHVCs) discovered by the Arecibo Legacy Fast ALFA (ALFALFA) Hi survey. UCHVCs have properties consistent with their being low-mass dwarf galaxies in the Local Volume, but do not have identified optical counterparts. We are using the WIYN 3.5 m telescope to image these objects and search for an associated stellar population. Here we present our observational strategy and method for searching for resolved stellar counterparts to the UCHVCs. We combine careful photometry, a color–magnitude filter, and spatial smoothing techniques to search for stellar overdensities in the g- and i-band images. We also run statistical tests to quantify the likelihood that detected overdensities are real and not chance superpositions of sources. We demonstrate the method by applying it to WIYN imaging of two objects: Leo P, a UCHVC discovered by ALFALFA and shown to be a star-forming dwarf galaxy in the Local Volume and AGC 198606, an ALFALFA source near in position and velocity to the Local Group dwarf galaxy Leo T. Applying the search method to the Leo P data yields an unambiguous detection (>99% confidence) of the galaxy’s stellar population. Applying the method to the AGC 198606 imaging yields a possible detection (92% confidence) of an optical counterpart located ∼2.5 arcmin from the centroid of AGC 198606's Hi distribution and within the Hi disk. We estimate a distance to the stellar counterpart of 373–393 kpc, an absolute magnitude Mi = ‑4.67 ± 0.09, and an Hi-to-stellar mass ratio of ∼45–110.

  2. Lower resistance and higher tolerance of invasive host plants: biocontrol agents reach high densities but exert weak control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    1. Invasive plants often have novel biotic interactions in their introduced ranges. Changes in herbivore defense traits are important for the effectiveness of biological control, because insect natural enemies may rapidly build up their populations on invasive plants due to decreased resistance but...

  3. NUCLEAR-MEDIATED MITOCHONDRIAL GENE REGULATION AND MALE FERTILITY IN HIGHER PLANTS: LIGHT AT THE END OF THE TUNNEL?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The exploitation of hybrid vigor in plants usually capitalizes on cytoplasmic male sterility (CMS), a maternally inherited trait characterized by the absence of functional pollen. Hybrids of many plants are produced using CMS, wherein a male-sterile line is grown adjacent to a selected male-fertile...

  4. Recent advances in the research for the homolog of breast cancer associated gene AtROW1 in higher plants.

    PubMed

    Jiao, Yue; Zhang, Yuzhou; Zhu, Yu-Xian

    2016-08-01

    BARD1 (BRCA1 associated RING domain protein 1), as an important animal tumor suppressor gene associated with many kinds of cancers, has been intensively studied for decades. Surprisingly, homolog of BARD1 was found in plants and it was renamed AtROW1 (repressor of Wuschel-1) according to its extremely important function with regard to plant stem cell homeostasis. Although great advances have been made in human BARD1, the function of this animal tumor-suppressor like gene in plant is not well studied and need to be further elucidated. Here, we review and summarize past and present work regarding this protein. Apart from its previously proposed role in DNA repair, recently it is found essential for shoot and root stem cell development and differentiation in plants. The study of AtROW1 in plant may provide an ideal model for further elucidating the functional mechanism of BARD1 in mammals. PMID:27502904

  5. Proteomic characterization and three-dimensional electron microscopy study of PSII-LHCII supercomplexes from higher plants.

    PubMed

    Pagliano, Cristina; Nield, Jon; Marsano, Francesco; Pape, Tillmann; Barera, Simone; Saracco, Guido; Barber, James

    2014-09-01

    In higher plants a variable number of peripheral LHCII trimers can strongly (S), moderately (M) or loosely (L) associate with the dimeric PSII core (C2) complex via monomeric Lhcb proteins to form PSII-LHCII supercomplexes with different structural organizations. By solubilizing isolated stacked pea thylakoid membranes either with the α or β isomeric forms of the detergent n-dodecyl-D-maltoside, followed by sucrose density ultracentrifugation, we previously showed that PSII-LHCII supercomplexes of types C2S2M2 and C2S2, respectively, can be isolated [S. Barera et al., Phil. Trans. R Soc. B 67 (2012) 3389-3399]. Here we analysed their protein composition by applying extensive bottom-up and top-down mass spectrometry on the two forms of the isolated supercomplexes. In this way, we revealed the presence of the antenna proteins Lhcb3 and Lhcb6 and of the extrinsic polypeptides PsbP, PsbQ and PsbR exclusively in the C2S2M2 supercomplex. Other proteins of the PSII core complex, common to the C2S2M2 and C2S2 supercomplexes, including the low molecular mass subunits, were also detected and characterized. To complement the proteomic study with structural information, we performed negative stain transmission electron microscopy and single particle analysis on the PSII-LHCII supercomplexes isolated from pea thylakoid membranes solubilized with n-dodecyl-α-D-maltoside. We observed the C2S2M2 supercomplex in its intact form as the largest PSII complex in our preparations. Its dataset was further analysed in silico, together with that of the second largest identified sub-population, corresponding to its C2S2 subcomplex. In this way, we calculated 3D electron density maps for the C2S2M2 and C2S2 supercomplexes, approaching respectively 30 and 28Å resolution, extended by molecular modelling towards the atomic level. This article is part of a special issue entitled: photosynthesis research for sustainability: keys to produce clean energy. PMID:24246636

  6. SEEKING COUNTERPARTS TO ADVANCED LIGO/Virgo TRANSIENTS WITH SWIFT

    SciTech Connect

    Kanner, Jonah; Camp, Jordan; Racusin, Judith; Gehrels, Neil; White, Darren

    2012-11-01

    Binary neutron star (NS) mergers are among the most promising astrophysical sources of gravitational wave (GW) emission for Advanced LIGO and Advanced Virgo, expected to be operational in 2015. Finding electromagnetic counterparts to these signals will be essential to placing them in an astronomical context. The Swift satellite carries a sensitive X-Ray Telescope (XRT), and can respond to target-of-opportunity requests within one to two hours, and so is uniquely poised to find the X-ray counterparts to LIGO/Virgo triggers. Assuming that NS mergers are the progenitors of short gamma-ray bursts (GRBs), some percentage of LIGO/Virgo triggers will be accompanied by X-ray band afterglows that are brighter than 10{sup -12} erg s{sup -1} cm{sup -2} in the XRT band one day after the trigger time. We find that a soft X-ray transient of this flux is bright enough to be extremely rare, and so could be confidently associated with even a moderately localized GW signal. We examine two possible search strategies with the Swift XRT to find bright transients in LIGO/Virgo error boxes. In the first strategy, XRT could search a volume of space with a {approx}100 Mpc radius by observing {approx}30 galaxies over the course of a day, with sufficient depth to observe the expected X-ray afterglow. For an extended LIGO/Virgo horizon distance, the XRT could employ 100 s exposures to cover an area of {approx}35 deg{sup 2} in about a day and remain sensitive enough to image GW-discovered GRB afterglows. These strategies demonstrate that discovery of X-ray band counterparts to GW triggers will be possible, though challenging, with current facilities.

  7. Seeking Counterparts to Advanced LIGO/Virgo Transients with Swift

    NASA Technical Reports Server (NTRS)

    Kanner, Jonah; Camp, Jordan; Racusin, Judith; Gehrels, Neil; White, Darren

    2012-01-01

    Binary neutron star (NS) mergers are among the most promising astrophysical sources of gravitational wave emission for Advanced LIGO and Advanced Virgo, expected to be operational in 2015 . Finding electromagnetic counterparts to these signals will be essential to placing them in an astronomical context. The Swift satellite carries a sensitive X-ray telescope (XRT), and can respond to target-of-opportunity requests within 1-2 hours, and so is uniquely poised to find the X-ray counterparts to LIGO / Virgo triggers. Assuming NS mergers are the progenitors of short gamma-ray bursts (GRBs), some percentage of LIGO/Virgo triggers will be accompanied by X-ray band afterglows that are brighter than 10(exp -12) ergs/s/sq cm in the XRT band one day after the trigger time. We find that a soft X-ray transient of this flux is bright enough to be extremely rare, and so could be confidently associated with even a moderately localized GW signal. We examine two possible search strategies with the Swift XRT to find bright transients in LIGO/Virgo error boxes. In the first strategy, XRT could search a volume of space with a approx.100 Mpc radius by observing approx 30 galaxies over the course of a day, with sufficient depth to observe the expected X-ray afterglow. For an extended LIGO / Virgo horizon distance, the XRT could employ very short 100 s exposures to cover an area of approx 35 square degrees in about a day, and still be sensitive enough to image GW discovered GRB afterglows. These strategies demonstrate that the high X-ray luminosity of short GRBs and the relatively low X-ray transient background combine to make high confidence discoveries of X-ray band counterparts to GW triggers possible, though challenging, with current satellite facilities.

  8. Silencing of the HvCKX1 gene decreases the cytokinin oxidase/dehydrogenase level in barley and leads to higher plant productivity.

    PubMed

    Zalewski, Wojciech; Galuszka, Petr; Gasparis, Sebastian; Orczyk, Wacław; Nadolska-Orczyk, Anna

    2010-06-01

    Stable RNA interference-based technology was used to silence the expression of the HvCKX1 gene in barley and the TaCKX1 gene in wheat and triticale. The silencing cassettes containing the fragments of these genes in the sense and antisense orientations were cloned into the pMCG161 binary vector and used for Agrobacterium-based transformation. Out of the five cultivars representing the three studied species, transgenic plants were obtained from one barley cultivar Golden Promise, one wheat cultivar Kontesa, and one triticale cultivar Wanad. Almost 80% of 52 regenerated lines of Golden Promise exhibited significantly decreased cytokinin oxidase/dehydrogenase (CKX) enzyme activity in bulked samples of their T(1) roots. There was a positive correlation between the enzyme activity and the plant productivity, expressed as the yield, the number of seeds per plant, and the 1000 grain weight. Additionally, these traits were associated with a greater root mass. Lower CKX activity led to a higher plant yield and root weight. This higher plant productivity and altered plant architecture were maintained in a population of segregating T(1) plants. The levels of HvCKX1 transcript accumulation were measured in various tissues of Golden Promise and Scarlett non-transgenic barley plants in order to choose the most appropriate plant organs to study the expression and/or silencing of the gene in those transgenic lines. The highest levels of the HvCKX1 transcript were detected in spikes 0 days after pollination (0 DAP), 7 DAP, and 14 DAP, and in the seedling roots. The analysis of HvCKX1 gene expression and CKX enzyme activity and the evaluation of the phenotype were performed in the progeny of seven selected transgenic T(1) lines. The relative expression of HvCKX1 measured in the spikes 0 DAP and 14 DAP, respectively, ranged from 0.52+/-0.04 to 1.15+/-0.26 and from 0.47+/-0.07 to 0.89+/-0.15. The lowest relative values were obtained for the enzyme activity in the spikes at 0 DAP

  9. Super LOTIS a high sensitive optical counterpart search experiment

    SciTech Connect

    Park, H.S., Ables, E.; Band, D.L

    1997-11-17

    We are constructing a 0.6 meter telescope system to search for early time gamma-ray burst (GRB) optical counterparts. Super-LOTIS (Super-Livermore Optical Transient Imaging System) is an automated telescope system that has a 0.8 x 0.8{degree} field-of-view, is sensitive to M{sub v} {approximately} 19 and responds to a burst trigger within 5 min. This telescope will record images of the gamma-ray burst coordinates that is given by the GCN (GRB Coordinate Network). A measurement of GRB light curves at early times will greatly enhance our understanding of GRB physics.

  10. Genetic and molecular basis of grain size and grain number and its relevance to grain productivity in higher plants.

    PubMed

    Gupta, Pushpendra K; Rustgi, Sachin; Kumar, Neeraj

    2006-06-01

    Grain size and grain number constitute 2 important components of grain yield. In particular, the grain size also influences the end-use quality (e.g., flour yield and protein content) and attracts consumer preference. These 2 traits are also the components of the domestication syndrome of crop plants. A number of important studies have recently been conducted to understand the genetic and molecular basis of these 2 important yield-contributing traits. Information generated from these studies was collected and synthesized for the benefit of plant biologists, particularly plant breeders. In the present article, this information is briefly reviewed and the prospects of using this information for improvement of grain productivity in crop plants are discussed. PMID:16936836

  11. Ab initio calculations of the Fe(II) and Fe(III) isotopic effects in citrates, nicotianamine, and phytosiderophore, and new Fe isotopic measurements in higher plants

    NASA Astrophysics Data System (ADS)

    Moynier, Frédéric; Fujii, Toshiyuki; Wang, Kun; Foriel, Julien

    2013-05-01

    Iron is one of the most abundant transition metal in higher plants and variations in its isotopic compositions can be used to trace its utilization. In order to better understand the effect of plant-induced isotopic fractionation on the global Fe cycling, we have estimated by quantum chemical calculations the magnitude of the isotopic fractionation between different Fe species relevant to the transport and storage of Fe in higher plants: Fe(II)-citrate, Fe(III)-citrate, Fe(II)-nicotianamine, and Fe(III)-phytosiderophore. The ab initio calculations show firstly, that Fe(II)-nicotianamine is ˜3‰ (56Fe/54Fe) isotopically lighter than Fe(III)-phytosiderophore; secondly, even in the absence of redox changes of Fe, change in the speciation alone can create up to ˜1.5‰ isotopic fractionation. For example, Fe(III)-phytosiderophore is up to 1.5‰ heavier than Fe(III)-citrate2 and Fe(II)-nicotianamine is up to 1‰ heavier than Fe(II)-citrate. In addition, in order to better understand the Fe isotopic fractionation between different plant components, we have analyzed the iron isotopic composition of different organs (roots, seeds, germinated seeds, leaves and stems) from six species of higher plants: the dicot lentil (Lens culinaris), and the graminaceous monocots Virginia wild rye (Elymus virginicus), Johnsongrass (Sorghum halepense), Kentucky bluegrass (Poa pratensis), river oat (Uniola latifolia), and Indian goosegrass (Eleusine indica). The calculations may explain that the roots of strategy-II plants (Fe(III)-phytosiderophore) are isotopically heavier (by about 1‰ for the δ56Fe) than the upper parts of the plants (Fe transported as Fe(III)-citrate in the xylem or Fe(II)-nicotianamine in the phloem). In addition, we suggest that the isotopic variations observed between younger and older leaves could be explained by mixing of Fe received from the xylem and the phloem.

  12. Extreme blazars as counterparts of IceCube astrophysical neutrinos

    NASA Astrophysics Data System (ADS)

    Padovani, P.; Resconi, E.; Giommi, P.; Arsioli, B.; Chang, Y. L.

    2016-04-01

    We explore the correlation of γ-ray emitting blazars with IceCube neutrinos by using three very recently completed, and independently built, catalogues and the latest neutrino lists. We introduce a new observable, namely the number of neutrino events with at least one γ-ray counterpart, Nν. In all three catalogues we consistently observe a positive fluctuation of Nν with respect to the mean random expectation at a significance level of 0.4-1.3 per cent. This applies only to extreme blazars, namely strong, very high energy γ-ray sources of the high energy peaked type, and implies a model-independent fraction of the current IceCube signal ˜10-20 per cent. An investigation of the hybrid photon - neutrino spectral energy distributions of the most likely candidates reveals a set of ≈5 such sources, which could be linked to the corresponding IceCube neutrinos. Other types of blazars, when testable, give null correlation results. Although we could not perform a similar correlation study for Galactic sources, we have also identified two (further) strong Galactic γ-ray sources as most probable counterparts of IceCube neutrinos through their hybrid spectral energy distributions. We have reasons to believe that our blazar results are not constrained by the γ-ray samples but by the neutrino statistics, which means that the detection of more astrophysical neutrinos could turn this first hint into a discovery.

  13. COMPACT OPTICAL COUNTERPARTS OF ULTRALUMINOUS X-RAY SOURCES

    SciTech Connect

    Tao Lian; Feng Hua; Grise, Fabien; Kaaret, Philip

    2011-08-20

    Using archival Hubble Space Telescope (HST) imaging data, we report the multiband photometric properties of 13 ultraluminous X-ray sources (ULXs) that have a unique compact optical counterpart. Both magnitude and color variation are detected at timescales of days to years. The optical color, variability, and X-ray to optical flux ratio indicate that the optical emission of most ULXs is dominated by X-ray reprocessing on the disk, similar to that of low-mass X-ray binaries. For most sources, the optical spectrum is a power law, F{sub {nu}}{proportional_to}{nu}{sup {alpha}} with {alpha} in the range 1.0-2.0 and the optically emitting region has a size on the order of 10{sup 12} cm. Exceptions are NGC 2403 X-1 and M83 IXO 82, which show optical spectra consistent with direct emission from a standard thin disk, M101 ULX-1 and M81 ULS1, which have X-ray to optical flux ratios more similar to high-mass X-ray binaries, and IC 342 X-1, in which the optical light may be dominated by the companion star. Inconsistent extinction between the optical counterpart of NGC 5204 X-1 and the nearby optical nebulae suggests that they may be unrelated.

  14. Evaluating the Effects of Illumination Quality on Higher Plant Value in the MARS 500-Day Mission Simulation

    NASA Astrophysics Data System (ADS)

    Marchant, C. C.; Karetkin, I. G.; Podolsky, I. G.; Bingham, G. E.

    2008-06-01

    Light-emitting diodes (LED) have a number of advantages over other light sources for space horticulture, including greater output efficiency, increased safety, and small size and mass. Much of the previous work with LEDs has ignored their effect on the plants' visible appearances. Part of the MARS 500 experiment at the IBMP in Moscow will be evaluating the plants' psychological value. In that experiment, white LEDs will be compared against fluorescent lighting to determine yield and perception effectiveness. For this study, the suitability of white LEDs for spaceflight is evaluated with respect to both biomass yield as well as plant appearance. In these studies, a variety of plant types have been used, including radish, leaf mustard, dwarf peas, and super-dwarf wheat. An LED bank with white elements is compared against a conventional fluorescent source and an LED bank with 90% red and 10% blue elements. Results showed biomass yield to be comparable for all three sources, but with species-specific reactions to LED lighting. White LEDs can significantly improve illumination efficiency relative to fluorescent lighting, while retaining the psychological value of the plants.

  15. Evaluation of the biotic potential of microorganisms and higher plants to enhance the quality of constructed wetlands. Final report

    SciTech Connect

    Mays, D.A.; Floyd, M.; Taylor, R.W.; Sistani, K.

    1998-09-30

    A project was carried out from October 1, 1991 through September 30, 1998 to evaluate the growth of several species of wetland plants in constructed cells using mine spoil as a growth medium, to evaluate microbial diversity and finally, to demonstrate the concept on an actual strip-mined site. In order to gain background information for evaluation of constructed wetlands, several wetlands on both undisturbed and strip-mined areas were evaluated to determine the physical and chemical characteristics of the substrates as well as the vegetation characteristics. The research phase of this projects consisted of 10 wetland cells each 7x16 m in size with the water depth varying from 0 to 40 cm. The substrates were allowed to stabilize over winter and each cell was planted in the spring of 1993 with 18 plants each of cattail, maidencance, soft stem bulrush and pickerel weed. All cells were thickly vegetated by the end of the first growing season.

  16. The phosphoproteome in regenerating protoplasts from Physcomitrella patens protonemata shows changes paralleling postembryonic development in higher plants

    PubMed Central

    He, Yikun

    2014-01-01

    The moss Physcomitrella patens is an ideal model plant to study plant developmental processes. To better understand the mechanism of protoplast regeneration, a phosphoproteome analysis was performed. Protoplasts were prepared from protonemata. By 4 d of protoplast regeneration, the first cell divisions had ensued. Through a highly selective titanium dioxide (TiO2)-based phosphopeptide enrichment method and mass spectrometric technology, more than 300 phosphoproteins were identified as protoplast regeneration responsive. Of these, 108 phosphoproteins were present on day 4 but not in fresh protoplasts or those cultured for 2 d. These proteins are catalogued here. They were involved in cell-wall metabolism, transcription, signal transduction, cell growth/division, and cell structure. These protein functions are related to cell morphogenesis, organogenesis, and development adjustment. This study presents a comprehensive analysis of phosphoproteome involved in protoplast regeneration and indicates that the mechanism of plant protoplast regeneration is similar to that of postembryonic development. PMID:24700621

  17. Microgravity effects on different stages of higher plant life cycle and completion of the seed-to-seed cycle.

    PubMed

    De Micco, V; De Pascale, S; Paradiso, R; Aronne, G

    2014-01-01

    Human inhabitation of Space requires the efficient realisation of crop cultivation in bioregenerative life-support systems (BLSS). It is well known that plants can grow under Space conditions; however, perturbations of many biological phenomena have been highlighted due to the effect of altered gravity and its possible interactions with other factors. The mechanisms priming plant responses to Space factors, as well as the consequences of such alterations on crop productivity, have not been completely elucidated. These perturbations can occur at different stages of plant life and are potentially responsible for failure of the completion of the seed-to-seed cycle. After brief consideration of the main constraints found in the most recent experiments aiming to produce seeds in Space, we focus on two developmental phases in which the plant life cycle can be interrupted more easily than in others also on Earth. The first regards seedling development and establishment; we discuss reasons for slow development at the seedling stage that often occurs under microgravity conditions and can reduce successful establishment. The second stage comprises gametogenesis and pollination; we focus on male gamete formation, also identifying potential constraints to subsequent fertilisation. We finally highlight how similar alterations at cytological level can not only be common to different processes occurring at different life stages, but can be primed by different stress factors; such alterations can be interpreted within the model of 'stress-induced morphogenic response' (SIMR). We conclude by suggesting that a systematic analysis of all growth and reproductive phases during the plant life cycle is needed to optimise resource use in plant-based BLSS. PMID:24015754

  18. A controlled aquatic ecological life support system (CAELSS) for combined production of fish and higher plant biomass suitable for integration into a lunar or planetary base.

    PubMed

    Blum, V; Andriske, M; Eichhorn, H; Kreuzberg, K; Schreibman, M P

    1995-10-01

    Based on the construction principle of the already operative Closed Equilibrated Biological Aquatic System (C.E.B.A.S.) the concept of an aquaculture system for combined production of animal and plant biomass was developed. It consists of a tank for intensive fish culture which is equipped with a feeding lock representing also a trap for biomass removal followed by a water recycling system. This is an optimized version of the original C.E.B.A.S. filters adapted to higher water pollutions. It operates in a fully biological mode and is able to convert the high ammonia ion concentrations excreted by the fish gills into nitrite ions. The second biomass production site is a higher plant cultivator with an internal fiber optics light distributor which may utilize of solar energy. The selected water plant is a tropical rootless duckweed of the genus Wolffia which possesses a high capacity in nitrate elimination and is terrestrially cultured as a vegetable for human nutrition in Southeast Asia. It is produced in an improved suspension culture which allows the removal of excess biomass by tangential centrifugation. The plant cultivator is able to supply the whole system with oxygen for respiration and eliminates vice versa the carbon dioxide exhaled by the fish via photosynthesis. A gas exchanger may be used for emergency purposes or to deliver excess oxygen into the environment and may be implemented into the air regeneration system of a closed environment of higher order. The plant biomass is fed into a biomass processor which delivers condensed fresh and dried biomass as pellets. The recovered water is fed back into the aquaculture loop. The fresh plants can be used for human nutrition immediately or can be stored after sterilization in an adequate packing. The dried Wolffia pellets are collected and brought into the fish tank by an automated feeder. In parallel the water from the plant cultivator is driven back to the animal tank by a pump. The special feature of the

  19. Polyamines and cellular metabolism in plants: Transgenic approaches reveal different responses to diamine putrescine versus higher polyamines spermidine and spermine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Distribution of biogenic amines – the diamine putrescine (Put), triamine spermidine (Spd), and tetraamine spermine (Spm) - differs between species with Put and Spd being particularly abundant and Spm the least abundant in plant cells. These amines are important for cell viability and their intracel...

  20. How endogenous plant cell-wall degradation mechanisms can help achieve higher efficiency in saccharification of biomass.

    PubMed

    Tavares, Eveline Q P; De Souza, Amanda P; Buckeridge, Marcos S

    2015-07-01

    Cell-wall recalcitrance to hydrolysis still represents one of the major bottlenecks for second-generation bioethanol production. This occurs despite the development of pre-treatments, the prospect of new enzymes, and the production of transgenic plants with less-recalcitrant cell walls. Recalcitrance, which is the intrinsic resistance to breakdown imposed by polymer assembly, is the result of inherent limitations in its three domains. These consist of: (i) porosity, associated with a pectin matrix impairing trafficking through the wall; (ii) the glycomic code, which refers to the fine-structural emergent complexity of cell-wall polymers that are unique to cells, tissues, and species; and (iii) cellulose crystallinity, which refers to the organization in micro- and/or macrofibrils. One way to circumvent recalcitrance could be by following cell-wall hydrolysis strategies underlying plant endogenous mechanisms that are optimized to precisely modify cell walls in planta. Thus, the cell-wall degradation that occurs during fruit ripening, abscission, storage cell-wall mobilization, and aerenchyma formation are reviewed in order to highlight how plants deal with recalcitrance and which are the routes to couple prospective enzymes and cocktail designs with cell-wall features. The manipulation of key enzyme levels in planta can help achieving biologically pre-treated walls (i.e. less recalcitrant) before plants are harvested for bioethanol production. This may be helpful in decreasing the costs associated with producing bioethanol from biomass. PMID:25922489

  1. Applications of CRISPR/Cas9 technology for targeted mutagenesis, gene replacement and stacking of genes in higher plants.

    PubMed

    Luo, Ming; Gilbert, Brian; Ayliffe, Michael

    2016-07-01

    Mutagenesis continues to play an essential role for understanding plant gene function and, in some instances, provides an opportunity for plant improvement. The development of gene editing technologies such as TALENs and zinc fingers has revolutionised the targeted mutation specificity that can now be achieved. The CRISPR/Cas9 system is the most recent addition to gene editing technologies and arguably the simplest requiring only two components; a small guide RNA molecule (sgRNA) and Cas9 endonuclease protein which complex to recognise and cleave a specific 20 bp target site present in a genome. Target specificity is determined by complementary base pairing between the sgRNA and target site sequence enabling highly specific, targeted mutation to be readily engineered. Upon target site cleavage, error-prone endogenous repair mechanisms produce small insertion/deletions at the target site usually resulting in loss of gene function. CRISPR/Cas9 gene editing has been rapidly adopted in plants and successfully undertaken in numerous species including major crop species. Its applications are not restricted to mutagenesis and target site cleavage can be exploited to promote sequence insertion or replacement by recombination. The multiple applications of this technology in plants are described. PMID:27146973

  2. Nature of the contribution of the polymers of cell walls of the higher plants to coal formation

    SciTech Connect

    Given, P.H.

    1983-08-29

    Three peat cores from differing environments in the Florida Everglades and one from the Okefenokee Swamp, Georgia, were collected in the field in 1982. The strategy adopted in this project is to hand-pick any large fragments of decayed plant tissue from peat samples and then separate plant debris from fine-grained humic material by passing a water slurry through an 80-mesh sieve. The large pieces, the +80-mesh and -80-mesh are then to be examined separately. The recognizable plant tissue is to be characterized botanically by microscopic study, and all samples are to be studied chemically as indicated below. The apparently simple operation of wet-sieving proved unexpectedly troublesome; the humic matter was incompletely removed from the +80-mesh material, and after drying it proved impossible to complete the separation. The earlier FTIR spectra were therefore made on unsatisfactory samples and interpretation was complex. More careful slurrying and operation on a smaller scale now routinely gives clean separations in the sense that the +80-mesh fibrous rootlets are free of humic matter. Microscopic examination of the -80-mesh material shows the presence of some very small fragments of plant tissue, but the selection of an 80-mesh sieve seems very reasonable in segregating plant tissue from amorphous granular material. Large pieces and the +80-mesh tissue are Soxhlet-extracted with benzene/ethanol before chemical study, to remove simple phenols, lipids, pigments, etc. The -80-mesh material is extracted both with 2N HCl at room temperature and with benzene/ethanol. Most of the data obtained so far derive from FTIR, though some /sup 13/C NMR spectra are available. Data for seven samples from three peat cores taken at different sites have been studied at the time of writing.

  3. Optical counterpart of 2A0311-227

    NASA Technical Reports Server (NTRS)

    Williams, G.; Johns, M.; Price, C.; Hiltner, A.; Boley, F.; Maker, S.; Mook, D.

    1979-01-01

    Spectrophotometric observations of the optical counterpart of the X-ray source 2A0311-227 are reported. A 1.3-m telescope associated with a photon-counting spectral scanner was used for observations in the range 4000 to 5800 A. Strong emission features are noted for H I, He II at 4686 A and the C III-N III blend at 4640-4650 A. Analyses of radial velocities show the star to be a spectroscopic binary with a period of 81.04 + or - 0.01 min, while blue and yellow light curves reveal variations in stellar color. Similarities between this binary and AM Herculis are noted and a model of a 1.2-solar mass white dwarf with a 0.2-solar mass companion at a separation of 0.7 solar radii is suggested.

  4. Dyadic Cantor set and its kinetic and stochastic counterpart

    NASA Astrophysics Data System (ADS)

    Hassan, M. K.; Pavel, N. I.; Pandit, R. K.; Kurths, J.

    2014-03-01

    Firstly, we propose and investigate a dyadic Cantor set (DCS) and its kinetic counterpart where a generator divides an interval into two equal parts and removes one with probability $(1-p)$. The generator is then applied at each step to all the existing intervals in the case of DCS and to only one interval, picked with probability according to interval size, in the case of kinetic DCS. Secondly, we propose a stochastic DCS in which, unlike the kinetic DCS, the generator divides an interval randomly instead of equally into two parts. Finally, the models are solved analytically; an exact expression for fractal dimension in each case is presented and the relationship between fractal dimension and the corresponding conserved quantity is pointed out. Besides, we show that the interval size distribution function in both variants of DCS exhibits dynamic scaling and we verify it numerically using the idea of data-collapse.

  5. Possible optical counterpart of PSR J1357-6429

    NASA Astrophysics Data System (ADS)

    Danilenko, A.; Kirichenko, A.; Mennickent, R. E.; Pavlov, G.; Shibanov, Yu.; Zharikov, S.; Zyuzin, D.

    2012-04-01

    Context. PSR J1357-6429 is a Vela-like radio pulsar that has been recently detected in X-rays and γ-rays. It powers a compact tail-like X-ray pulsar wind nebula and X-ray-radio plerion associated with an extended TeV source HESS J1356-645. Aims: We present our deep optical observations with the Very Large Telescope to search for an optical counterpart of the pulsar and its nebula. Methods: The observations were carried out using a direct imaging mode in the V, R, and I bands. We also analysed archival X-ray data obtained with Chandra and XMM-Newton. Results: In all three optical bands, we detect a point-like source with V = 27.3 ± 0.3, R = 25.52 ± 0.07, and I = 24.13 ± 0.05, whose position is within the 1σ error circle of the X-ray position of the pulsar, and whose colours are distinct from those of ordinary stars. We consider it as a candidate optical counterpart of the pulsar. If it is indeed the counterpart, its 5σ offset from the radio pulsar position, measured about 9 yr earlier, implies that the transverse velocity of the pulsar is in the range of 1600-2000 km s-1 at the distance of 2-2.5 kpc, making it the fastest moving pulsar known. The direction of the estimated proper motion coincides with the extension of the pulsar's X-ray tail, suggesting that this is a jet. The tentative optical luminosity and efficiency of the pulsar are similar to those of the Vela pulsar, which also supports the optical identification. However, the candidate undergoes an unusually steep dereddened flux increase towards the infrared with a spectral index αν ~ 5, that is not typical of optical pulsars. It implies a strong double-knee spectral break in the pulsar emission between the optical and X-rays. The reasons for the spectral steepness are unclear. It may be caused by a nebula knot projected onto the jet and strongly overlapping with the pulsar, as observed for the Crab, where the knot has a significantly steeper spectrum than the pulsar. We find no other signs of the

  6. Electromagnetic Counterparts of Gravitational Wave Sources: Mergers of Compact Objects

    NASA Astrophysics Data System (ADS)

    Kamble, Atish; Kaplan, David L. A.

    2013-01-01

    Mergers of compact objects are considered prime sources of gravitational waves (GW) and will soon be targets of GW observatories such as the Advanced-LIGO and VIRGO. Finding electromagnetic counterparts of these GW sources will be important to understand their nature. We discuss possible electromagnetic signatures of the mergers. We show that the BH-BH mergers could have luminosities which exceed Eddington luminosity from unity to several orders of magnitude depending on the masses of the merging BHs. As a result these mergers could be explosive, release up to 1051 erg of energy and shine as radio transients. At any given time we expect about a few such transients in the sky at GHz frequencies, which could be detected to be about 300 Mpc. It has also been argued that these radio transients would look alike radio supernovae with comparable detection rates. Multi-band follow-up could, however, distinguish between the mergers and supernovae.

  7. Spectroscopic observations of the optical counterpart of Centaurus X-4

    NASA Technical Reports Server (NTRS)

    Van Paradijs, J.; Verbunt, F.; Van Der Linden, T.; Pedersen, H.; Wamsteker, W.

    1980-01-01

    The optical spectrum of the transient X-ray burst source Centaurus X-4 was observed about 5 weeks after the source reached its maximum. The brightness of the optical counterpart had decreased to V = 18.2, and the star had become appreciably redder (B - V = 0.7) compared to its color at maximum. The spectrum of Centaurus X-4 is similar to that of cataclysmic variables showing strong emission lines of H-1 and weaker lines of He-1 and He-2. The N03 lambda 4640 line is not visible. The continuum energy distribution of Centaurus X-4 shows the presence of a main-sequence star in the system, with spectral type between K3 and K7. This is consistent with the orbital period of 8.2 hr proposed by Kaluzienski et al (1980), if the main-sequence star is close to filling its Roche lobe.

  8. X-ray Counterparts of Infrared Faint Radio Sources

    NASA Astrophysics Data System (ADS)

    Schartel, Norbert

    2011-10-01

    Infrared Faint Radio Sources (IFRS) are radio sources with extremely faint or even absent infrared emission in deep Spitzer Surveys. Models of their spectral energy distributions, the ratios of radio to infrared flux densities and their steep radio spectra strongly suggest that IFRS are AGN at high redshifts (2counterparts of IFRS is considered to be the smoking gun for this hypothesis. We propose to observe 8 IFRS using 30ks pointed observations. X-ray detections of IFRS with different ratios of radio-to-infrared fluxes, will constrain the class-specific SED.

  9. Chandra Counterparts of CANDELS GOODS-S Sources

    NASA Astrophysics Data System (ADS)

    Cappelluti, N.; Comastri, A.; Fontana, A.; Zamorani, G.; Amorin, R.; Castellano, M.; Merlin, E.; Santini, P.; Elbaz, D.; Schreiber, C.; Shu, X.; Wang, T.; Dunlop, J. S.; Bourne, N.; Bruce, V. A.; Buitrago, F.; Michałowski, Michał J.; Derriere, S.; Ferguson, H. C.; Faber, S. M.; Vito, F.

    2016-06-01

    Improving the capabilities of detecting faint X-ray sources is fundamental for increasing the statistics on faint high-z active galactic nuclei (AGNs) and star-forming galaxies (SFGs). We performed a simultaneous maximum likelihood point-spread function fit in the [0.5–2] keV and [2–7] keV energy bands of the 4 Ms Chandra Deep Field South (CDFS) data at the position of the 34,930 CANDELS H-band selected galaxies. For each detected source we provide X-ray photometry and optical counterpart validation. We validated this technique by means of a ray-tracing simulation. We detected a total of 698 X-ray point sources with a likelihood { L }\\gt 4.98 (i.e., >2.7σ). We show that prior knowledge of a deep sample of optical–NIR galaxies leads to a significant increase in the detection of faint (i.e., ˜10‑17 cgs in the [0.5–2] keV band) sources with respect to “blind” X-ray detections. By including previous X-ray catalogs, this work increases the total number of X-ray sources detected in the 4 Ms CDFS, CANDELS area to 793, which represents the largest sample of extremely faint X-ray sources assembled to date. Our results suggest that a large fraction of the optical counterparts of our X-ray sources determined by likelihood ratio actually coincides with the priors used for the source detection. Most of the new detected sources are likely SFGs or faint, absorbed AGNs. We identified a few sources with putative photometric redshift z > 4. Despite the low number statistics and the uncertainties on the photo z, this sample significantly increases the number of X-ray-selected candidate high-z AGNs.

  10. Chandra Counterparts of CANDELS GOODS-S Sources

    NASA Astrophysics Data System (ADS)

    Cappelluti, N.; Comastri, A.; Fontana, A.; Zamorani, G.; Amorin, R.; Castellano, M.; Merlin, E.; Santini, P.; Elbaz, D.; Schreiber, C.; Shu, X.; Wang, T.; Dunlop, J. S.; Bourne, N.; Bruce, V. A.; Buitrago, F.; Michałowski, Michał J.; Derriere, S.; Ferguson, H. C.; Faber, S. M.; Vito, F.

    2016-06-01

    Improving the capabilities of detecting faint X-ray sources is fundamental for increasing the statistics on faint high-z active galactic nuclei (AGNs) and star-forming galaxies (SFGs). We performed a simultaneous maximum likelihood point-spread function fit in the [0.5–2] keV and [2–7] keV energy bands of the 4 Ms Chandra Deep Field South (CDFS) data at the position of the 34,930 CANDELS H-band selected galaxies. For each detected source we provide X-ray photometry and optical counterpart validation. We validated this technique by means of a ray-tracing simulation. We detected a total of 698 X-ray point sources with a likelihood { L }\\gt 4.98 (i.e., >2.7σ). We show that prior knowledge of a deep sample of optical–NIR galaxies leads to a significant increase in the detection of faint (i.e., ∼10‑17 cgs in the [0.5–2] keV band) sources with respect to “blind” X-ray detections. By including previous X-ray catalogs, this work increases the total number of X-ray sources detected in the 4 Ms CDFS, CANDELS area to 793, which represents the largest sample of extremely faint X-ray sources assembled to date. Our results suggest that a large fraction of the optical counterparts of our X-ray sources determined by likelihood ratio actually coincides with the priors used for the source detection. Most of the new detected sources are likely SFGs or faint, absorbed AGNs. We identified a few sources with putative photometric redshift z > 4. Despite the low number statistics and the uncertainties on the photo z, this sample significantly increases the number of X-ray-selected candidate high-z AGNs.

  11. The Faint Counterparts of MAMBO Millimeter Sources near the New Technology Telescope Deep Field

    NASA Astrophysics Data System (ADS)

    Dannerbauer, H.; Lehnert, M. D.; Lutz, D.; Tacconi, L.; Bertoldi, F.; Carilli, C.; Genzel, R.; Menten, K. M.

    2004-05-01

    We discuss identifications for 18 sources from our Max-Planck-Millimeter-Bolometer (MAMBO) 1.2 mm survey of the region surrounding the NTT Deep Field. We have obtained accurate positions from Very Large Array 1.4 GHz interferometry, and in a few cases IRAM millimeter interferometry, and have also made deep BVRIzJK imaging at ESO. We find thirteen 1.2 mm sources associated with optical/near-infrared objects in the magnitude range K=19.0-22.5, while five are blank fields at K>22. We argue from a comparison of optical/near-infrared photometric redshifts and radio/millimeter redshift estimates that two of the 13 optical/near-infrared objects are likely foreground objects distinct from the dust sources, one of them possibly lensing the millimeter source. The median redshift of the radio-identified millimeter sources is ~2.6 from the radio/millimeter estimator, and the median optical/near-infrared photometric redshifts for the objects with counterparts is ~2.1. This suggests that those radio-identified millimeter sources without optical/near-infrared counterparts tend to lie at higher redshifts than those with optical/near-infrared counterparts. Compared to published identifications of objects from 850 μm surveys of similar depth, the median K and I magnitudes of our counterparts are roughly 2 mag fainter, and the dispersion of I-K colors is less. Real differences in the median redshifts, residual misidentifications with bright objects, cosmic variance, and small-number statistics are likely to contribute to this significant difference, which also affects redshift measurement strategies. Some of the counterparts are red in J-K (>~20%), but the contribution of such millimeter objects to the recently studied population of near-infrared-selected (Js-Ks>2.3) high-redshift galaxies is only of order a few percent. The recovery rate of MAMBO sources by preselection of optically faint radio sources is relatively low (~25%), in contrast to some claims of a higher rate for

  12. Evaluation of higher plant virus resistance genes in the green alga, Chlorella variabilis NC64A, during the early phase of infection with Paramecium bursaria chlorella virus-1.

    PubMed

    Rowe, Janet M; Dunigan, David D; Blanc, Guillaume; Gurnon, James R; Xia, Yuannan; Van Etten, James L

    2013-08-01

    With growing industrial interest in algae plus their critical roles in aquatic systems, the need to understand the effects of algal pathogens is increasing. We examined a model algal host-virus system, Chlorella variabilis NC64A and virus, PBCV-1. C. variabilis encodes 375 homologs to genes involved in RNA silencing and in response to virus infection in higher plants. Illumina RNA-Seq data showed that 325 of these homologs were expressed in healthy and early PBCV-1 infected (≤60min) cells. For each of the RNA silencing genes to which homologs were found, mRNA transcripts were detected in healthy and infected cells. C. variabilis, like higher plants, may employ certain RNA silencing pathways to defend itself against virus infection. To our knowledge this is the first examination of RNA silencing genes in algae beyond core proteins, and the first analysis of their transcription during virus infection. PMID:23701839

  13. Evaluation of higher plant virus resistance genes in the green alga, Chlorella variabilis NC64A, during the early phase of infection with Paramecium bursaria chlorella virus-1

    PubMed Central

    Rowe, Janet M.; Dunigan, David D.; Blanc, Guillaume; Gurnon, James R.; Xia, Yuannan; Van Etten, James L.

    2014-01-01

    With growing industrial interest in algae plus their critical roles in aquatic systems, the need to understand the effects of algal pathogens is increasing. We examined a model algal host–virus system, Chlorella variabilis NC64A and virus, PBCV-1. C. variabilis encodes 375 homologs to genes involved in RNA silencing and in response to virus infection in higher plants. Illumina RNA-Seq data showed that 325 of these homologs were expressed in healthy and early PBCV-1 infected (≤60 min) cells. For each of the RNA silencing genes to which homologs were found, mRNA transcripts were detected in healthy and infected cells. C. variabilis, like higher plants, may employ certain RNA silencing pathways to defend itself against virus infection. To our knowledge this is the first examination of RNA silencing genes in algae beyond core proteins, and the first analysis of their transcription during virus infection. PMID:23701839

  14. Development of a simple PCR-based assay for the identification of triazine resistance in the noxious plant common ragweed (Ambrosia artemisiifolia) and its applicability in higher plants.

    PubMed

    Mátyás, Kinga Klára; Taller, János; Cseh, András; Poczai, Péter; Cernák, István

    2011-12-01

    Bidirectional allele-specific PCR (Bi-PASA) was used to detect a point mutation causing triazine resistance in common ragweed (Ambrosia artemisiifolia). The external primers amplified a 278 bp standard DNA fragment in all genotypes. In the susceptible S264S genotypes, a 208 bp fragment was expected while in resistant S264G common ragweed genotypes a 109 bp band was expected. In resistant plants, both the wild and mutant type fragments were detected, indicating that the original triazine sensitive cpDNA is maintained in a heteroplasmic state in the resistant S264G genotypes. Additionally, in silico analysis confirmed the potential applicability of our diagnostic assay for other plant species. In 24 out of 74 taxa (32%), the assay could be used without any change, while in the others some of the primers should be redesigned before use. PMID:21809088

  15. Distinct patterns of expression but similar biochemical properties of protein L-isoaspartyl methyltransferase in higher plants.

    PubMed

    Thapar, N; Kim, A K; Clarke, S

    2001-02-01

    Protein L-isoaspartyl methyltransferase is a widely distributed repair enzyme that initiates the conversion of abnormal L-isoaspartyl residues to their normal L-aspartyl forms. Here we show that this activity is expressed in developing corn (Zea mays) and carrot (Daucus carota var. Danvers Half Long) plants in patterns distinct from those previously seen in winter wheat (Triticum aestivum cv Augusta) and thale cress (Arabidopsis thaliana), whereas the pattern of expression observed in rice (Oryza sativa) is similar to that of winter wheat. Although high levels of activity are found in the seeds of all of these plants, relatively high levels of activity in vegetative tissues are only found in corn and carrot. The activity in leaves was found to decrease with aging, an unexpected finding given the postulated role of this enzyme in repairing age-damaged proteins. In contrast with the situation in wheat and Arabidopsis, we found that osmotic or salt stress could increase the methyltransferase activity in newly germinated seeds (but not in seeds or seedlings), whereas abscisic acid had no effect. We found that the corn, rice, and carrot enzymes have comparable affinity for methyl-accepting substrates and similar optimal temperatures for activity of 45 degrees C to 55 degrees C as the wheat and Arabidopsis enzymes. These experiments suggest that this enzyme may have specific roles in different plant tissues despite a common catalytic function. PMID:11161058

  16. Two cytochrome P-450 isoforms catalysing O-de-ethylation of ethoxycoumarin and ethoxyresorufin in higher plants.

    PubMed Central

    Werck-Reichhart, D; Gabriac, B; Teutsch, H; Durst, F

    1990-01-01

    The O-dealkylating activities of 7-ethoxycoumarin O-de-ethylase (ECOD) and 7-ethoxyresorufin O-de-ethylase (EROD) have been fluorimetrically detected in microsomes prepared from manganese-induced Jerusalem artichoke tubers. Cytochrome P-450 dependence of the reactions was demonstrated by light-reversed CO inhibition, NADPH-dependence, NADH-NADPH synergism and by use of specific inhibitors: antibodies to NADPH-cytochrome P-450 reductase, mechanism-based inactivators and tetcyclasis. Apparent Km values of 161 microM for 7-ethoxycoumarin and 0.4 microM for 7-ethoxyresorufin were determined. O-De-ethylase activity was also detected in microsomes prepared from several other plant species, including wheat, maize, tulip, avocado and Vicia. ECOD and EROD were low or undetectable in uninduced plant tissues, and both activities were stimulated by wounding or by chemical inducers. Two distinct cytochrome P-450 isoforms are involved in ECOD and EROD activities since (1) they showed different distributions among plant species; (2) they showed contrasting inhibition and induction patterns; and (3) ECOD but not EROD activity was supported by cumene hydroperoxide. PMID:2241905

  17. Requirements of blue, UV-A, and UV-B light for normal growth of higher plants, as assessed by action spectra for growth and related phenomena

    NASA Technical Reports Server (NTRS)

    Hashimoto, T.

    1994-01-01

    Artificial lighting is very important for experimental purposes, as well as for the practical use of plants when not enough sunlight is available. To grow green higher plants in their normal forms under artificial lighting constructing efficient and economically reasonable lighting systems is not an easy task. One possible approach would be to simulate sunlight in intensity and the radiation spectrum, but its high construction and running costs are not likely to allow its use in practice. Sunlight may be excessive in irradiance in some or all portions of the spectrum. Reducing irradiance and removing unnecessary wavebands might lead to an economically feasible light source. However, removing or reducing a particular waveband from sunlight for testing is not easy. Another approach might be to find the wavebands required for respective aspects of plant growth and to combine them in a proper ratio and intensity. The latter approach seems more practical and economical, and the aim of this Workshop lies in advancing this approach. I summarize our present knowledge on the waveband requirements of higher plants for the regions of blue, UV-A and UV-B.

  18. Expression, purification, crystallization and preliminary X-ray analysis of perakine reductase, a new member of the aldo-keto reductase enzyme superfamily from higher plants

    SciTech Connect

    Rosenthal, Cindy; Mueller, Uwe; Panjikar, Santosh; Sun, Lianli; Ruppert, Martin; Zhao, Yu; Stöckigt, Joachim

    2006-12-01

    Perakine reductase, a novel member of the aldo-keto reductase enzyme superfamily of higher plants, is involved in the biosynthesis of monoterpenoid indole alkaloids in the Indian medicinal plant Rauvolfia serpentina. The enzyme has been crystallized in C-centered orthorhombic space group and diffracts to 2.0 Å resolution. Perakine reductase (PR) is a novel member of the aldo-keto reductase enzyme superfamily from higher plants. PR from the plant Rauvolfia serpentina is involved in the biosynthesis of monoterpenoid indole alkaloids by performing NADPH-dependent reduction of perakine, yielding raucaffrinoline. However, PR can also reduce cinnamic aldehyde and some of its derivatives. After heterologous expression of a triple mutant of PR in Escherichia coli, crystals of the purified and methylated enzyme were obtained by the hanging-drop vapour-diffusion technique at 293 K with 100 mM sodium citrate pH 5.6 and 27% PEG 4000 as precipitant. Crystals belong to space group C222{sub 1} and diffract to 2.0 Å, with unit-cell parameters a = 58.9, b = 93.0, c = 143.4 Å.

  19. Carbon dioxide and the stomatal control of water balance and photosynthesis in higher plants. Progress report, July 1, 1990--June 30, 1992

    SciTech Connect

    Not Available

    1992-07-01

    Research continued into the investigation of the effects of carbon dioxide on stomatal control of water balance and photosynthesis in higher plants. Topics discussed this period include a method of isolating a sufficient number of guard cell chloroplasts for biochemical studies by mechanical isolation of epidermal peels; the measurement of stomatal apertures with a digital image analysis system; development of a high performance liquid chromatography method for quantification of metabolites in guard cells; and genetic control of stomatal movements in Pima cotton. (CBS)

  20. Optimal multiyear management of a water supply system under uncertainty: Robust counterpart approach

    NASA Astrophysics Data System (ADS)

    Housh, Mashor; Ostfeld, Avi; Shamir, Uri

    2011-10-01

    In this paper, the robust counterpart (RC) approach (Ben-Tal et al., 2009) is applied to optimize management of a water supply system (WSS) fed from aquifers and desalination plants. The water is conveyed through a network to meet desired consumptions, where the aquifers recharges are uncertain. The objective is to minimize the net present value cost of multiyear operation, satisfying operational and physical constraints. The RC is a min-max guided approach, which converts the original problem into a deterministic equivalent problem, requiring only that the uncertain parameters resides within a user-defined uncertainty set. The robust policy obtained by the RC approach is compared with polices obtained by other decision-making approaches including stochastic approaches.

  1. Distinct localization of two closely related Ypt3/Rab11 proteins on the trafficking pathway in higher plants.

    PubMed

    Inaba, Takehito; Nagano, Yukio; Nagasaki, Takeshi; Sasaki, Yukiko

    2002-03-15

    Ypt/Rab proteins are Ras-related small GTPases that act on the intracellular membrane through the trafficking pathway, and their function depends on their localization. Approximately 25 genes encoding Ypt3/Rab11-related proteins exist in Arabidopsis, but the reason for the presence of many genes in plants remains unclear. Pea Pra2 and Pra3, members of Ypt3/Rab11, are closely related proteins. Because possible orthologs are conserved among dicots, they can be studied to determine their possible localization. Biochemical analysis revealed that these proteins were localized on distinct membranes in pea. Furthermore, using green fluorescent protein-Pra2 and green fluorescent protein-Pra3 fusion proteins, we demonstrated that these proteins are distinctively localized on the trafficking pathway in tobacco Bright Yellow 2 cells. Pra2 was predominantly localized on Golgi stacks and endosomes, which did not support the localization of Pra2 on the endoplasmic reticulum (Kang, J. G., Yun, J., Kim, D. H., Chung, K. S., Fujioka, S., Kim, J. I., Dae, H. W., Yoshida, S., Takatsuto, S., Song, P. S., and Park, C. M. (2001) Cell 105, 625--636). In contrast, Pra3 was likely to be localized on the trans-Golgi network and/or the prevacuolar compartment. We concluded that Pra2 and Pra3 proteins are distinctively localized on the trafficking pathway. This finding suggests that functional diversification takes place in the plant Ypt3/Rab11 family. PMID:11756458

  2. Preferential inhibition of the lycopene epsilon-cyclase by the substituted triethylamine compound MPTA in higher plants.

    PubMed

    Phillip, Denise M; Young, Andrew J

    2006-03-01

    In addition to the usual complement of carotenoids found in the plant leaf tissues, lettuce (Lactuca sativa), unusually, possesses large amounts of the diol lactucaxanthin. This carotenoid possesses two epsilon-end-groups and its presence provides a good model in which to study the effects of the substituted triethylamine compound 2-(4-methylphenoxy)triethylamine (MPTA) on the cyclisation of beta- and epsilon-end-groups during the biosynthesis of carotenoids. Treatment with 10 or 20microM MPTA significantly reduced levels of both beta-carotene and neoxanthin (up to 18-fold), whilst levels of violaxanthin and lutein were less affected (4-fold reduction). In contrast, levels of lactucaxanthin were not reduced even at the highest inhibitor concentration, and at 10microM MPTA levels of this xanthophyll doubled. The pigment stoichiometry of the bulk light-harvesting complex (LHCIIb) isolated from treated plants shows that lactucaxanthin successfully substituted for lutein and neoxanthin in two of the xanthophyll binding sites, namely L2 and N1. Inhibition of cyclisation was accompanied by the accumulation of lycopene and trace amounts of delta-carotene and a number of oxygenated derivatives of these precursors. Two forms of mono-hydroxy lycopene were identified together with mono-epoxy delta-carotene. PMID:16455351

  3. Do Lower Calorie or Lower Fat Foods Have More Sodium Than Their Regular Counterparts?

    PubMed

    John, Katherine A; Maalouf, Joyce; B Barsness, Christina; Yuan, Keming; Cogswell, Mary E; Gunn, Janelle P

    2016-01-01

    The objective of this study was to compare the sodium content of a regular food and its lower calorie/fat counterpart. Four food categories, among the top 20 contributing the most sodium to the US diet, met the criteria of having the most matches between regular foods and their lower calorie/fat counterparts. A protocol was used to search websites to create a list of "matches", a regular and comparable lower calorie/fat food(s) under each brand. Nutrient information was recorded and analyzed for matches. In total, 283 matches were identified across four food categories: savory snacks (N = 44), cheese (N = 105), salad dressings (N = 90), and soups (N = 44). As expected, foods modified from their regular versions had significantly reduced average fat (total fat and saturated fat) and caloric profiles. Mean sodium content among modified salad dressings and cheeses was on average 8%-12% higher, while sodium content did not change with modification of savory snacks. Modified soups had significantly lower mean sodium content than their regular versions (28%-38%). Consumers trying to maintain a healthy diet should consider that sodium content may vary in foods modified to be lower in calories/fat. PMID:27548218

  4. Do Lower Calorie or Lower Fat Foods Have More Sodium Than Their Regular Counterparts?

    PubMed Central

    John, Katherine A.; Maalouf, Joyce; B. Barsness, Christina; Yuan, Keming; Cogswell, Mary E.; Gunn, Janelle P.

    2016-01-01

    The objective of this study was to compare the sodium content of a regular food and its lower calorie/fat counterpart. Four food categories, among the top 20 contributing the most sodium to the US diet, met the criteria of having the most matches between regular foods and their lower calorie/fat counterparts. A protocol was used to search websites to create a list of “matches”, a regular and comparable lower calorie/fat food(s) under each brand. Nutrient information was recorded and analyzed for matches. In total, 283 matches were identified across four food categories: savory snacks (N = 44), cheese (N = 105), salad dressings (N = 90), and soups (N = 44). As expected, foods modified from their regular versions had significantly reduced average fat (total fat and saturated fat) and caloric profiles. Mean sodium content among modified salad dressings and cheeses was on average 8%–12% higher, while sodium content did not change with modification of savory snacks. Modified soups had significantly lower mean sodium content than their regular versions (28%–38%). Consumers trying to maintain a healthy diet should consider that sodium content may vary in foods modified to be lower in calories/fat. PMID:27548218

  5. Conservation of functional features of U6atac and U12 snRNAs between vertebrates and higher plants.

    PubMed

    Shukla, G C; Padgett, R A

    1999-04-01

    Splicing of U12-dependent introns requires the function of U11, U12, U6atac, U4atac, and U5 snRNAs. Recent studies have suggested that U6atac and U12 snRNAs interact extensively with each other, as well as with the pre-mRNA by Watson-Crick base pairing. The overall structure and many of the sequences are very similar to the highly conserved analogous regions of U6 and U2 snRNAs. We have identified the homologs of U6atac and U12 snRNAs in the plant Arabidopsis thaliana. These snRNAs are significantly diverged from human, showing overall identities of 65% for U6atac and 55% for U12 snRNA. However, there is almost complete conservation of the sequences and structures that are implicated in splicing. The sequence of plant U6atac snRNA shows complete conservation of the nucleotides that base pair to the 5' splice site sequences of U12-dependent introns in human. The immediately adjacent AGAGA sequence, which is found in human U6atac and all U6 snRNAs, is also conserved. High conservation is also observed in the sequences of U6atac and U12 that are believed to base pair with each other. The intramolecular U6atac stem-loop structure immediately adjacent to the U12 interaction region differs from the human sequence in 9 out of 21 positions. Most of these differences are in base pairing regions with compensatory changes occurring across the stem. To show that this stem-loop was functional, it was transplanted into a human suppressor U6atac snRNA expression construct. This chimeric snRNA was inactive in vivo but could be rescued by coexpression of a U4atac snRNA expression construct containing compensatory mutations that restored base pairing to the chimeric U6atac snRNA. These data show that base pairing of U4atac snRNA to U6atac snRNA has a required role in vivo and that the plant U6atac intramolecular stem-loop is the functional analog of the human sequence. PMID:10199569

  6. A dynamic counterpart of Lamb vector in viscous compressible aerodynamics

    NASA Astrophysics Data System (ADS)

    Liu, L. Q.; Wu, J. Z.; Shi, Y. P.; Zhu, J. Y.

    2014-12-01

    The Lamb vector is known to play a key role in incompressible fluid dynamics and vortex dynamics. In particular, in low-speed steady aerodynamics it is solely responsible for the total force acting on a moving body, known as the vortex force, with the classic two-dimensional (exact) Kutta-Joukowski theorem and three-dimensional (linearized) lifting-line theory as the most famous special applications. In this paper we identify an innovative dynamic counterpart of the Lamb vector in viscous compressible aerodynamics, which we call the compressible Lamb vector. Mathematically, we present a theorem on the dynamic far-field decay law of the vorticity and dilatation fields, and thereby prove that the generalized Lamb vector enjoys exactly the same integral properties as the Lamb vector does in incompressible flow, and hence the vortex-force theory can be generalized to compressible flow with exactly the same general formulation. Moreover, for steady flow of polytropic gas, we show that physically the force exerted on a moving body by the gas consists of a transverse force produced by the original Lamb vector and a new longitudinal force that reflects the effects of compression and irreversible thermodynamics.

  7. The Hunt for a Counterpart to GW150914

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-07-01

    On 14 September 2015, the Laser Interferometer Gravitational-wave Observatory (LIGO) in a pre-operative testing state at the time detected its first sign of gravitational-waves. The LIGO team sprang into action, performing data-quality checks on this unexpected signal. Within two days, they had sent a notification to 63 observing teams at observatories representing the entire electromagnetic spectrum, from radio to gamma-ray wavelengths.Illustration of a binary neutron star merger. The neutron stars 1) inspiral, 2) can produce a short gamma-ray burst, 3) can fling out hot, radioactive material in the form of a kilonova, and 4) form a massive neutron star or black hole with a possible remnant debris disk around it. [NASA/ESA/A. Feild (STScI)]Thus began the very first hunt for an electromagnetic counterpart to a detected gravitational wave signal.What were they looking for?As two compact objects in a binary system merge, the system is expected to emit energy in the form of gravitational waves. If both of the compact objects are black holes, were unlikely to see any electromagnetic radiation in the process, unless the merger is occurring in an (improbable) environment filled with gas and dust.But if one or both of the two compact objects is a neutron star, then there are a number of electromagnetic signatures that could occur due to energetic outflows. If a relativistic jet forms, we could see a short gamma-ray burst and X-ray, optical, and radio afterglows. Sub-relativistic outflows could produce optical and near-infrared signals, or a radio blast wave.Timeline of observations of GW150914, separated by wavelength band, and relative to the time of the gravitational-wave trigger. The top row shows LIGO information releases. The bottom four rows show high-energy, optical, near-infrared, and radio observations, respectively. Click for a closer look! [Abbott et al. 2016]Surprise SignalSince LIGO and Virgo (LIGOs European counterpart), wereprimarily expecting to detect

  8. Electromagnetic Counterparts to Black Hole Mergers Detected by LIGO

    NASA Astrophysics Data System (ADS)

    Loeb, Abraham

    2016-03-01

    Mergers of stellar-mass black holes (BHs), such as GW150914 observed by Laser Interferometer Gravitational Wave Observatory (LIGO), are not expected to have electromagnetic counterparts. However, the Fermi GBM detector identified a γ-ray transient 0.4 s after the gravitational wave (GW) signal GW150914 with consistent sky localization. I show that the two signals might be related if the BH binary detected by LIGO originated from two clumps in a dumbbell configuration that formed when the core of a rapidly rotating massive star collapsed. In that case, the BH binary merger was followed by a γ-ray burst (GRB) from a jet that originated in the accretion flow around the remnant BH. A future detection of a GRB afterglow could be used to determine the redshift and precise localization of the source. A population of standard GW sirens with GRB redshifts would provide a new approach for precise measurements of cosmological distances as a function of redshift.

  9. Gamma ray burst optical counterpart search experiment (GROCSE)

    SciTech Connect

    Park, Hye-Sook; Ables, Elden; Bionta, Richard M.; Ott, Linda; Parker, Eric; Akerlof, Carl; Lee, Brian; Wallace, Scott; Barthelmy, Scott; Butterworth, Paul; Cline, Thomas; Gehrels, Neil; Fishman, Gerald; Kouveliotou, Chryssa; Meegan, Charles; Ferguson, Donald

    1996-08-01

    GROCSE (Gamma-Ray Optical Counterpart Search Experiment) is a system of automated telescopes that search for simultaneous optical activity associated with gamma ray bursts in response to real-time burst notifications provided by the BATSE/BACODINE network. The first generation system, GROCSE I, is sensitive down to M{sub V}{approx}8.5 and requires an average of 12 seconds to obtain the first images of the gamma ray burst error box defined by the BACODINE trigger. The collaboration is now constructing a second generation system which has a 4 second slewing time and can reach M{sub V}{approx}14 with a 5 second exposure. GROCSE II consists of 4 cameras on a single mount. Each camera views the night sky through a commercial Canon lens (f/1.8, focal length 200 mm) and utilizes a 2Kx2K Loral CCD. Light weight and low noise custom readout electronics were designed and fabricated for these CCDs. The total field of view of the 4 cameras is 17.6x17.6 deg. GROCSE II will be operating by the end of 1995. In this paper, we present an overview of the GROCSE system and the results of measurements with a GROCSE II prototype unit.

  10. Gamma Ray Burst Optical Counterpart Search Experiment (GROCSE)

    SciTech Connect

    Park, H.S.; Ables, E.; Bionta, R.M.

    1995-10-27

    GROCSE (Gamma-Ray Optical Counterpart Search Experiments) is a system of automated telescopes that search for simultaneous optical activity associated with gamma ray bursts in response to real-time burst notifications provided by the BATSE/BACODINE network. The first generation system, GROCSE 1, is sensitive down to Mv {approximately} 8.5 and requires an average of 12 seconds to obtain the first images of the gamma ray burst error box defined by the BACODINE trigger. The collaboration is now constructing a second generation system which has a 4 second slewing time and can reach Mv {approximately} 14 with a 5 second exposure. GROCSE 2 consists of 4 cameras on a single mount. Each camera views the night sky through a commercial Canon lens (f/1.8, focal length 200 mm) and utilizes a 2K x 2K Loral CCD. Light weight and low noise custom readout electronics were designed and fabricated for these CCDs. The total field of view of the 4 cameras is 17.6 x 17.6 {degree}. GROCSE II will be operated by the end of 1995. In this paper, the authors present an overview of the GROCSE system and the results of measurements with a GROCSE 2 prototype unit.

  11. The current psychoanalytic dialogue: its counterpart in Renaissance philosophy.

    PubMed

    Grolnick, S A

    1982-01-01

    It is my premise that psychoanalysis is involved in a phase of metapsychological and technical debate typical during the course of intellectual history. In general, the more traditional school textually conceptualizes psychoanalysis as a natural, observational science involving subject-object duality, determinism, and causality, and tends to separate theory and practice, interspersing a force-energy metapsychology. The recent critics of traditional theory view psychoanalysis as closer to cultural science and art. They do not subscribe to a strict determinism and conceptualize that they work more within a field of free will. Their tendency to keep theory close to practice leads to more experience-colored, closer to the clinical, theoretical models. I have tried to provide some early evidence that, through mutual influence, a dialectic is rising above the heat of this debate, with each group incorporating some of the ideas of the other. At the same time, since all differences are not true polarities, and not all polarities can be reconciled, the possibility that psychoanalytic theory will necessarily reach a new level of synthesis must be looked upon with caution. It is hoped that a broad view of this theoretical struggle in psychoanalysis can be enriched by an awareness among its participants of the related counterparts in Western intellectual history. PMID:6927011

  12. Fermi GBM Counterparts to LIGO Gravitational-Wave Candidates

    NASA Astrophysics Data System (ADS)

    Connaughton, Valerie; Blackburn, Lindy; Briggs, Michael Stephen; Burns, Eric; Camp, Jordan; Dal Canton, Tito; Christensen, Nelson; Goldstein, Adam; Jenke, Peter; Littenberg, Tyson; Racusin, Judith L.; Shawhan, Peter S.; Singer, Leo; Veitch, John; Wilson-Hodge, Colleen; Zhang, Binbin

    2016-01-01

    As the advanced configuration of the Laser Interferometer Gravitational-wave Observatory (LIGO) begins operations, we eagerly anticipate the detection of gravitational waves (GW) with LIGO in coincidence with a gamma-ray signal from the Fermi Gamma-ray Burst Monitor (GBM). The most likely source is a short Gamma-Ray Burst (GRB) arising from the merger of two compact objects. With its broad sky coverage, GBM triggers and localizes more short GRBs than other active space missions, ~45 each year, with an estimate of <1-5 within the LIGO detection horizon. Combining GBM and LIGO localization uncertainty regions may provide a smaller target to look for the GW host. A joint GBM-LIGO detection increases the confidence in the GW detection and helps characterize the parameters of the merger. Offline searches for weak GRBs that fail to trigger onboard Fermi indicate that additional short GRBs can be detected in the GBM data. I will discuss the implementation and expected benefits of joint searches to detect and localize GW candidates. I will also explore how the non-detection in the GBM data of a signal consistent with GW candidates in the LIGO data can affect follow-up strategies for counterpart searches by other observers.

  13. Fermi GBM Counterparts to LIGO Gravitational-Wave Candidates

    NASA Astrophysics Data System (ADS)

    Burns, Eric; Blackburn, Lindy; Briggs, Michael Stephen; Camp, Jordan; Christensen, Nelson; Connaughton, Valerie; Goldstein, Adam; Littenberg, Tyson; Racusin, Judith L.; Shawhan, Peter S.; Pound Singer, Leo; Veitch, John; Zhang, Binbin

    2016-04-01

    As the advanced configuration of the Laser Interferometer Gravitational-wave Observatory has begun operations, we eagerly anticipate the detection of gravitational waves (GW) with LIGO in coincidence with a gamma-ray signal from the Fermi Gamma-ray Burst Monitor (GBM). The most likely source is a short Gamma-Ray Burst (GRB) arising from the merger of two compact objects. With its broad sky coverage, GBM triggers and localizes more short GRBs than other active space missions, ~40 each year. Combining GBM and LIGO localization uncertainty regions may provide a smaller target to look for the GW host. A joint GBM-LIGO detection increases the confidence in the GW detection and helps characterize the parameters of the merger. Offline searches for weak GRBs that fail to trigger onboard Fermi indicate that additional short GRBs can be detected in the GBM data. I will discuss the implementation and expected benefits of joint searches to detect and localize GW candidates. I will also explore how the non-detection in the GBM data of a signal consistent with GW candidates in the LIGO data can affect follow-up strategies for counterpart searches by other observers.

  14. Fermi GBM Counterparts to LIGO Gravitational-Wave Candidates

    NASA Astrophysics Data System (ADS)

    Racusin, Judith; Blackburn, Lindy; Briggs, Michael; Burns, Eric; Camp, Jordan; Canton, Tito Dal; Christensen, Nelson; Connaughton, Valerie; Goldstein, Adam; Jenke, Peter; Littenberg, Tyson; Shawhan, Peter; Singer, Leo; Veitch, John; Wilson-Hodge, Colleen; Zhang, Binbin

    2016-03-01

    As advanced LIGO begins operations, we eagerly anticipate the detection of gravitational waves (GW) in coincidence with a gamma-ray signal from the Fermi Gamma-ray Burst Monitor (GBM). The most likely source is a short Gamma-Ray Burst (GRB) arising from the merger of two neutron stars. With its broad sky coverage, GBM triggers and localizes more short GRBs than other active space missions, 45 each year, with an estimate of <1-5 within the LIGO detection horizon. Combining GBM and LIGO localization uncertainty regions may provide a smaller region for GW host searches. A joint GBM-LIGO detection increases the confidence in the GW detection and helps characterize the parameters of the merger. Offline searches for weak GRBs that fail to trigger onboard Fermi indicate that additional short GRBs can be detected in the GBM data. I will discuss joint searches to detect and localize GW candidates, and explore how the non-detection in the GBM data of a signal consistent with GW candidates in the LIGO data can affect follow-up strategies for counterpart searches by other observers.

  15. Torrefaction of invasive alien plants: Influence of heating rate and other conversion parameters on mass yield and higher heating value.

    PubMed

    Mundike, Jhonnah; Collard, François-Xavier; Görgens, Johann F

    2016-06-01

    With the aim of controlling their proliferation, two invasive alien plants, Lantana camara (LC) and Mimosa pigra (MP), both widespread in Africa, were considered for torrefaction for renewable energy applications. Using thermogravimetric analysis, the influence of heating rate (HR: 2.18-19.82°Cmin(-1)) together with variable temperature and hold time on char yield and HHV (in a bomb calorimeter) were determined. Statistically significant effects of HR on HHV with optima at 10.5°Cmin(-1) for LC and 20°Cmin(-1) for MP were obtained. Increases of HHV up to 0.8MJkg(-1) or energy yield greater than 10%, together with a 3-fold reduction in torrefaction conversion time could be achieved by optimisation of HR. Analysis of the torrefaction volatiles by TG-MS showed that not only hemicelluloses, but also lignin conversion, could influence the optimum HR value. PMID:26954309

  16. Three-band model for noninvasive estimation of chlorophyll, carotenoids, and anthocyanin contents in higher plant leaves

    NASA Astrophysics Data System (ADS)

    Gitelson, Anatoly A.; Keydan, Galina P.; Merzlyak, Mark N.

    2006-06-01

    Leaf pigment content and composition provide important information about plant physiological status. Reflectance measurements offer a rapid, nondestructive technique to estimate pigment content. This paper describes a recently developed three-band conceptual model capable of remotely estimating total of chlorophylls, carotenoids and anthocyanins contents in leaves from many tree and crop species. We tuned the spectral regions used in the model in accord with pigment of interest and the optical characteristics of the leaves studied, and showed that the developed technique allowed accurate estimation of total chlorophylls, carotenoids and anthocyanins, explaining more than 91%, 70% and 93% of pigment variation, respectively. This new technique shows a great potential for noninvasive tracking of the physiological status of vegetation and the impact of environmental changes.

  17. AMT1;1 transgenic rice plants with enhanced NH4(+) permeability show superior growth and higher yield under optimal and suboptimal NH4(+) conditions.

    PubMed

    Ranathunge, Kosala; El-Kereamy, Ashraf; Gidda, Satinder; Bi, Yong-Mei; Rothstein, Steven J

    2014-03-01

    The major source of nitrogen for rice (Oryza sativa L.) is ammonium (NH4(+)). The NH4(+) uptake of roots is mainly governed by membrane transporters, with OsAMT1;1 being a prominent member of the OsAMT1 gene family that is known to be involved in NH4(+) transport in rice plants. However, little is known about its involvement in NH4(+) uptake in rice roots and subsequent effects on NH4(+) assimilation. This study shows that OsAMT1;1 is a constitutively expressed, nitrogen-responsive gene, and its protein product is localized in the plasma membrane. Its expression level is under the control of circadian rhythm. Transgenic rice lines (L-2 and L-3) overexpressing the OsAMT1;1 gene had the same root structure as the wild type (WT). However, they had 2-fold greater NH4(+) permeability than the WT, whereas OsAMT1;1 gene expression was 20-fold higher than in the WT. Analogous to the expression, transgenic lines had a higher NH4(+) content in the shoots and roots than the WT. Direct NH4(+) fluxes in the xylem showed that the transgenic lines had significantly greater uptake rates than the WT. Higher NH4(+) contents also promoted higher expression levels of genes in the nitrogen assimilation pathway, resulting in greater nitrogen assimilates, chlorophyll, starch, sugars, and grain yield in transgenic lines than in the WT under suboptimal and optimal nitrogen conditions. OsAMT1;1 also enhanced overall plant growth, especially under suboptimal NH4(+) levels. These results suggest that OsAMT1;1 has the potential for improving nitrogen use efficiency, plant growth, and grain yield under both suboptimal and optimal nitrogen fertilizer conditions. PMID:24420570

  18. AMT1;1 transgenic rice plants with enhanced NH4 + permeability show superior growth and higher yield under optimal and suboptimal NH4 + conditions

    PubMed Central

    Rothstein, Steven J.

    2014-01-01

    The major source of nitrogen for rice (Oryza sativa L.) is ammonium (NH4 +). The NH4 + uptake of roots is mainly governed by membrane transporters, with OsAMT1;1 being a prominent member of the OsAMT1 gene family that is known to be involved in NH4 + transport in rice plants. However, little is known about its involvement in NH4 + uptake in rice roots and subsequent effects on NH4 + assimilation. This study shows that OsAMT1;1 is a constitutively expressed, nitrogen-responsive gene, and its protein product is localized in the plasma membrane. Its expression level is under the control of circadian rhythm. Transgenic rice lines (L-2 and L-3) overexpressing the OsAMT1;1 gene had the same root structure as the wild type (WT). However, they had 2-fold greater NH4 + permeability than the WT, whereas OsAMT1;1 gene expression was 20-fold higher than in the WT. Analogous to the expression, transgenic lines had a higher NH4 + content in the shoots and roots than the WT. Direct NH4 + fluxes in the xylem showed that the transgenic lines had significantly greater uptake rates than the WT. Higher NH4 + contents also promoted higher expression levels of genes in the nitrogen assimilation pathway, resulting in greater nitrogen assimilates, chlorophyll, starch, sugars, and grain yield in transgenic lines than in the WT under suboptimal and optimal nitrogen conditions. OsAMT1;1 also enhanced overall plant growth, especially under suboptimal NH4 + levels. These results suggest that OsAMT1;1 has the potential for improving nitrogen use efficiency, plant growth, and grain yield under both suboptimal and optimal nitrogen fertilizer conditions. PMID:24420570

  19. Generation of poly-β-hydroxybutyrate from acetate in higher plants: Detection of acetoacetyl CoA reductase- and PHB synthase- activities in rice.

    PubMed

    Tsuda, Hirohisa; Shiraki, Mari; Inoue, Eri; Saito, Terumi

    2016-08-20

    It has been reported that Poly-β-hydroxybutyrate (PHB) is generated from acetate in the rice root. However, no information is available about the biosynthetic pathway of PHB from acetate in plant cells. In the bacterium Ralstonia eutropha H16 (R. eutropha), PHB is synthesized from acetyl CoA by the consecutive reaction of three enzymes: β-ketothiolase (EC: 2.3.1.9), acetoacetyl CoA reductase (EC: 1.1.1.36) and PHB synthase (EC: 2.3.1.-). Thus, in this study, we examined whether the above three enzymatic activities were also detected in rice seedlings. The results clearly showed that the activities of the above three enzymes were all detected in rice. In particular, the PHB synthase activity was detected specifically in the sonicated particulate fractions (2000g 10min precipitate (ppt) and the 8000g 30min ppt) of rice roots and leaves. In addition to these enzyme activities, several new experimental results were obtained on PHB synthesis in higher plants: (a) (14)C-PHB generated from 2-(14)C-acetate was mainly localized in the 2000g 10min ppt and the 8000g 30min ppt of rice root. (b) Addition of acetate (0.1-10mM) to culture medium of rice seedlings did not increase the content of PHB in the rice root or leaf. (c) In addition to C3 plants, PHB was generated from acetate in a C4 plant (corn) and in a CAM plant (Bryophyllum pinnatum). d) Washing with ethylenediaminetetraacetic acid (EDTA) strongly suggested that the PHB synthesized from acetate was of plant origin and was not bacterial contamination. PMID:27372278

  20. DNA injury induced by 5-aminouracil and caffeine in G2 checkpoints path of higher plant cells.

    PubMed

    Del Campo, A; Bracho, M; Marcano, L; Guíñez, J; De la Torre, C

    2005-08-01

    This work evaluated the qualitative and quantitative cellular changes induced by treatment with 5-aminouracil (5-AU) and a combination of 5-AU and caffeine in plant cells in relation to DNA damage, repaired damage, and residual damage. As biological material, Allium cepa L. root tips were used, grown in filtered water, in darkness, with aeration at constant temperature of 25 degrees C +/- 0.5. Cell populations were synchronized using 5 mM caffeine in order to study the effects of 5-AU and caffeine/5-AU combined treatment on the DNA content and their incidence in the entrance to mitosis. The results showed a delay in the G2 period due to induced DNA damage by the 5-AU and caffeine/5-AU combined treatment, shown by aberrant metaphases, anaphases and telophases. The effect of caffeine in the combined treatment was heightened in spite of lengthening the checkpoints route that retains the cells in G2. The existence of G2 checkpoints was shown in the cell population studied, inducing lesions in the DNA, chromosomic aberrations and cellular instability. PMID:16187495

  1. Merging ``real'' neutron stars for gravitational waves and electromagnetic counterparts

    NASA Astrophysics Data System (ADS)

    Duez, Matthew

    2014-03-01

    Having more-or-less succeeded in learning to stably evolve Einstein's equations, numerical relativity is taking the leap to including the physics of neutron stars, which will enable us to construct truly realistic pictures of neutron star-neutron star and black hole-neutron star binary mergers. The neutron star profile affects late inspirals and mergers, leaving its imprint on gravitational waveforms and electromagnetic counterpart signals. Furthermore, we expect neutrino radiation, magnetic field, and nuclear recombination effects to drive the post-merger evolution. In this talk, I will describe some recent neutron star merger simulations combining nuclear physics and general relativity. The goal is to connect assumptions about the nuclear equation of state and the premerger binary to resulting binary trajectories, matter outflows, accretion disk dynamics, and neutrino energy output. These can then hopefully be connected to observable signals in the form of gravitational waves, kilonovae, and gamma ray bursts. It is found that an interesting variety of disks, outflows, and neutrino bursts are possible. Connections to observables are being attempted by tracking nuclear reactions in tidal ejecta and estimating energy injection to gamma ray bursts from neutrino annihilation and other sources. Meanwhile, non-vacuum inspiral simulations are finally approaching the length and accuracy needed for interesting comparisons with binary black hole waveforms and post-Newtonian predictions, these being steps toward a reliable characterization of the imprint of the nuclear equation of state on the gravitational waves. The speaker acknowledges support from NASA Grant No. NNX11AC37G and NSF Grant PHY-1068243.

  2. Can we match ultraviolet face images against their visible counterparts?

    NASA Astrophysics Data System (ADS)

    Narang, Neeru; Bourlai, Thirimachos; Hornak, Lawrence A.

    2015-05-01

    In law enforcement and security applications, the acquisition of face images is critical in producing key trace evidence for the successful identification of potential threats. However, face recognition (FR) for face images captured using different camera sensors, and under variable illumination conditions, and expressions is very challenging. In this paper, we investigate the advantages and limitations of the heterogeneous problem of matching ultra violet (from 100 nm to 400 nm in wavelength) or UV, face images against their visible (VIS) counterparts, when all face images are captured under controlled conditions. The contributions of our work are three-fold; (i) We used a camera sensor designed with the capability to acquire UV images at short-ranges, and generated a dual-band (VIS and UV) database that is composed of multiple, full frontal, face images of 50 subjects. Two sessions were collected that span over the period of 2 months. (ii) For each dataset, we determined which set of face image pre-processing algorithms are more suitable for face matching, and, finally, (iii) we determined which FR algorithm better matches cross-band face images, resulting in high rank-1 identification rates. Experimental results show that our cross spectral matching (the heterogeneous problem, where gallery and probe sets consist of face images acquired in different spectral bands) algorithms achieve sufficient identification performance. However, we also conclude that the problem under study, is very challenging, and it requires further investigation to address real-world law enforcement or military applications. To the best of our knowledge, this is first time in the open literature the problem of cross-spectral matching of UV against VIS band face images is being investigated.

  3. Observations of optical counterparts of Gamma-Ray bursts

    NASA Technical Reports Server (NTRS)

    Knight, Frederick K.

    1992-01-01

    This is a final report for a contract begun in Dec. 1987 and ended in Mar. 1989 to use the existing Lincoln Laboratory Experimental Test Site in Socorro, NM to search for optical counterparts to gamma-ray bursts. The objective was to develop an autonomous staring system to search for stationary, transient optical flashes. The search was to use an existing 31-inch telescope equipped with a sensitive video detector. The approach for the search was to develop real-time processing software to monitor the video signal from the detector and to record any transient, point-like flashes that occurred in the field of view. The system would have been able to detect fainter flashes (B is approximately 15(sup m) in 1/30 s, delta(m(sub v)) = 0.25(sup m)) than other systems but lacked a large field of view (only 1.2 deg diameter) necessary to give a high probability of detecting a random flash on the sky. As such, the plan was to monitor known gamma-ray burst error boxes and wait for a repetition of an earlier event. The high payoff of good sensitivity with high angular resolution (1 pixel = 10sec) and good time resolution (30 s) to allow post-burst searches warranted funding if the cost was not prohibitive. The contract began in the middle of the three-year cycle for High Energy Astrophysics Gamma-Ray Astronomy Research and Analysis Program. This final report briefly describes the portion of the plan completed under the original contract.

  4. Search for simultaneous optical counterparts of gamma-ray bursts

    SciTech Connect

    Park, H S; Porrata, R A; Bionta, R M; Williams, G G

    2000-09-05

    Gamma Ray Bursts (GRBs) are brief, randomly located, releases of gamma-ray energy from unknown celestial sources that occur almost daily. The study of GRBs has undergone a revolution in the past three years due to an international effort of follow-up observations made possible by the instantaneous distribution of reliable GRB coordinate information over the internet provided by NASA's GCN (GRB Coordinates Network). The 3-year LDRD project described here, done in collaboration with the workers responsible for the GCN, was the very first serious system to actively utilize the GCN and thus played a major role in the development of the GCN and the dramatic increase in our understanding of GRBs. The scientific objective of this project was to measure the intensity of any prompt visible radiation accompanying the gamma-ray emission utilizing a small but sensitive robotic telescope that responded to GCN triggers by rapidly taking images of the GCN error box. The instrument developed for this project, LOTIS, was the first of its kind, and the longest running, collecting data on over 75 GRBs during its 3 year running period. The results of LOTIS and the other follow-up programs have now shown that GRBs are at cosmological distances and interact with surrounding material as described by the ''fireball model.'' Visible, prompt, optical counterparts have only been seen in one case and are therefore very rare or much dimmer than the sensitivity of the current instruments. This places numerical limits on the surrounding matter density, and other physical parameters in the GRB environment. A much more sensitive instrument, Super-LOTIS, has been developed for operation at Kitt-Peak.

  5. The Hunt for a Counterpart to GW150914

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-07-01

    On 14 September 2015, the Laser Interferometer Gravitational-wave Observatory (LIGO) in a pre-operative testing state at the time detected its first sign of gravitational-waves. The LIGO team sprang into action, performing data-quality checks on this unexpected signal. Within two days, they had sent a notification to 63 observing teams at observatories representing the entire electromagnetic spectrum, from radio to gamma-ray wavelengths.Illustration of a binary neutron star merger. The neutron stars 1) inspiral, 2) can produce a short gamma-ray burst, 3) can fling out hot, radioactive material in the form of a kilonova, and 4) form a massive neutron star or black hole with a possible remnant debris disk around it. [NASA/ESA/A. Feild (STScI)]Thus began the very first hunt for an electromagnetic counterpart to a detected gravitational wave signal.What were they looking for?As two compact objects in a binary system merge, the system is expected to emit energy in the form of gravitational waves. If both of the compact objects are black holes, were unlikely to see any electromagnetic radiation in the process, unless the merger is occurring in an (improbable) environment filled with gas and dust.But if one or both of the two compact objects is a neutron star, then there are a number of electromagnetic signatures that could occur due to energetic outflows. If a relativistic jet forms, we could see a short gamma-ray burst and X-ray, optical, and radio afterglows. Sub-relativistic outflows could produce optical and near-infrared signals, or a radio blast wave.Timeline of observations of GW150914, separated by wavelength band, and relative to the time of the gravitational-wave trigger. The top row shows LIGO information releases. The bottom four rows show high-energy, optical, near-infrared, and radio observations, respectively. Click for a closer look! [Abbott et al. 2016]Surprise SignalSince LIGO and Virgo (LIGOs European counterpart), wereprimarily expecting to detect

  6. Expression of a higher plant psbA gene in Synechocystis 6803 yields a functional hybrid photosystem II reaction center complex.

    PubMed Central

    Nixon, P J; Rögner, M; Diner, B A

    1991-01-01

    The psbA gene codes for the D1 polypeptide of the photosystem II reaction center complex and is found in all photosynthetic organisms that carry out oxygenic photosynthesis. Here we describe the construction and characterization of a strain of the cyanobacterium Synechocystis sp PCC 6803 in which the three endogenous psbA genes are replaced by a single psbA gene from the chloroplast genome of the higher plant Poa annua. The resulting chimeric strain, KWPAS, grows photoautotrophically with a doubling time of 26 hours compared with 20 hours for wild-type Synechocystis 6803. The mutant oxidizes water to oxygen at light-saturated rates comparable with wild type, despite differences in 15% of the primary structure of D1 between these species. RNA gel blot analysis indicates the presence in KWPAS of a psbA transcript of approximately 1.25 kilobases, consistent with the chloroplast promoter also acting as a promoter in Synechocystis. By using antibodies specific for the carboxyl-terminal extension of the D1 polypeptide of higher plants, we showed that the D1 polypeptide synthesized by KWPAS is post-translationally modified at the carboxyl terminus, probably through processing. A detailed biophysical analysis of the chimeric photosystem II complex indicated that the rates of forward electron transfer are similar to wild type. The rates of charge recombination between the donor and acceptor sides of the reaction center are, however, accelerated by as much as a factor of nine (QA- to S2) and are the most likely explanation for the lower rate of photoautotrophic growth in the mutant. We conclude that the psbA gene from a higher plant can be expressed in cyanobacteria and its product processed and assembled into a functional chimeric photosystem II reaction center. PMID:1840918

  7. Isotopic Niche Variation in a Higher Trophic Level Ectotherm: Highlighting the Role of Succulent Plants in Desert Food Webs

    PubMed Central

    Delibes, Miguel; Blazquez, Ma Carmen; Fedriani, Jose Maria; Granados, Arsenio; Soriano, Laura; Delgado, Antonio

    2015-01-01

    Stable isotope analysis of animal tissues allows description of isotopic niches, whose axes in an n-dimensional space are the isotopic ratios, compared to a standard, of different isotope systems (e.g. δ13C, δ15N). Isotopic niches are informative about where an animal, population or species lives and about what it consumes. Here we describe inter- and intrapopulation isotopic niche (bidimensional δ13C-δ15N space) of the Orange-throated whiptail (Aspidoscelis hyperythra), an arthropodivorous small lizard, in ten localities of Baja California Sur (Mexico). These localities range from extreme arid to subtropical conditions. Between 13 and 20 individuals were sampled at each locality and 1 cm of tail-tip was collected for isotope analysis. As expected, interpopulation niche width variation was much larger than intrapopulation one. Besides, isotopic variation was not related to age, sex or individual size of lizards. This suggests geographic variation of the isotopic niche was related to changes in the basal resources that fuel the trophic web at each locality. The position of Bayesian isotope ellipses in the δ-space indicated that whiptails in more arid localities were enriched in 13C, suggesting most of the carbon they ingested came from CAM succulent plants (cacti, agaves) and in minor degree in C4 grasses. Contrarily, whiptails in subtropical areas were depleted in 13C, as they received more carbon from C3 scrubs and trees. Localities closer to sea-level tended to be enriched in 15N, but a clear influence of marine subsidies was detected only at individual level. The study contributes to identify the origin and pathways through which energy flows across the trophic webs of North American deserts. PMID:25973609

  8. Translocation of the precursor of 5-enolpyruvylshikimate-3-phosphate synthase into chloroplasts of higher plants in vitro

    PubMed Central

    Della-Cioppa, Guy; Bauer, S. Christopher; Klein, Barbara K.; Shah, Dilip M.; Fraley, Robert T.; Kishore, Ganesh M.

    1986-01-01

    5-enolPyruvylshikimate-3-phosphate synthase (EPSP synthase; 3-phosphoshikimate 1-carboxyvinyl-transferase; EC 2.5.1.19) is a chloroplast-localized enzyme of the shikimate pathway in plants. This enzyme is the target for the nonselective herbicide glyphosate (N-phosphonomethylglycine). We have previously isolated a full-length cDNA clone of EPSP synthase from Petunia hybrida. DNA sequence analysis suggested that the enzyme is synthesized as a cytosolic precursor (pre-EPSP synthase) with an amino-terminal transit peptide. Based on the known amino terminus of the mature enzyme, and the 5′ open reading frame of the cDNA, the transit peptide of pre-EPSP synthase would be maximally 72 amino acids long. To confirm this prediction and to assay directly for translocation of pre-EPSP synthase into chloroplasts in vitro, we cloned the full-length cDNA into an SP6 transcription system to produce large amounts of mRNA for in vitro translation. The translation products, when analyzed by NaDodSO4/PAGE autoradiography, indicate a relative molecular mass for pre-EPSP synthase of ≈55 kDa. Uptake studies with intact chloroplasts, in vitro, indicate that pre-EPSP synthase was rapidly taken up into chloroplasts and proteolytically cleaved to the mature ≈48-kDa enzyme. The transit peptide was shown to be essential for import of the precursor enzyme into the chloroplast. To our knowledge, post-translational import into chloroplasts of a precursor enzyme involved in amino acid biosynthesis has not been reported previously. Furthermore, enzymatic analysis of translation products indicates that pre-EPSP synthase is catalytically active and has a similar sensitivity to the herbicide glyphosate as the mature enzyme. To our knowledge, pre-EPSP synthase represents the only example of a catalytically competent chloroplast-precursor enzyme. Images PMID:16593759

  9. Isotopic niche variation in a higher trophic level ectotherm: highlighting the role of succulent plants in desert food webs.

    PubMed

    Delibes, Miguel; Blazquez, Ma Carmen; Fedriani, Jose Maria; Granados, Arsenio; Soriano, Laura; Delgado, Antonio

    2015-01-01

    Stable isotope analysis of animal tissues allows description of isotopic niches, whose axes in an n-dimensional space are the isotopic ratios, compared to a standard, of different isotope systems (e.g. δ(13)C, δ(15)N). Isotopic niches are informative about where an animal, population or species lives and about what it consumes. Here we describe inter- and intrapopulation isotopic niche (bidimensional δ(13)C-δ(15)N space) of the Orange-throated whiptail (Aspidoscelis hyperythra), an arthropodivorous small lizard, in ten localities of Baja California Sur (Mexico). These localities range from extreme arid to subtropical conditions. Between 13 and 20 individuals were sampled at each locality and 1 cm of tail-tip was collected for isotope analysis. As expected, interpopulation niche width variation was much larger than intrapopulation one. Besides, isotopic variation was not related to age, sex or individual size of lizards. This suggests geographic variation of the isotopic niche was related to changes in the basal resources that fuel the trophic web at each locality. The position of Bayesian isotope ellipses in the δ-space indicated that whiptails in more arid localities were enriched in 13C, suggesting most of the carbon they ingested came from CAM succulent plants (cacti, agaves) and in minor degree in C4 grasses. Contrarily, whiptails in subtropical areas were depleted in 13C, as they received more carbon from C3 scrubs and trees. Localities closer to sea-level tended to be enriched in 15N, but a clear influence of marine subsidies was detected only at individual level. The study contributes to identify the origin and pathways through which energy flows across the trophic webs of North American deserts. PMID:25973609

  10. Toxicity of combined chromium(VI) and phenanthrene pollution on the seed germination, stem lengths, and fresh weights of higher plants.

    PubMed

    Hu, Shuangqing; Gu, Hairong; Cui, Chunyan; Ji, Rong

    2016-08-01

    Studies of the interaction and toxicity of pollutant combinations such as heavy metals and PAHs are of practical importance in the remediation and monitoring of the industrial soil environment. This study investigated the single and combined toxicity of chromium(VI) and phenanthrene on three important higher plants: mung beans (Phaseolus aureus), pakchoi cabbage (Brassica chinensis), and rice (Oryza sativa). In experiments using artificial soil matrix, the EC10 and EC20 of the two pollutants, alone and in combination, were analyzed with respect to seed germination, stem length, and above-ground fresh weight of these higher plants. The additive index method was used to evaluate the combined biological toxicity of chromium(VI) and phenanthrene. The results showed that the EC20 of chromium(VI) on the stem lengths of mung beans, pakchoi cabbage, and rice was 289, 248, and 550 mg kg(-1), respectively. The corresponding EC20 values for the fresh weights of the three plants were 334, 307, and 551 mg kg(-1). The EC20 of phenanthrene on the stem lengths of mung beans, pakchoi cabbage, and rice was 528, 426, and 628 mg kg(-1), respectively. The corresponding EC20 values for the fresh weights of the three plants were 696, 585, and 768 mg kg(-1). The EC20 of a combination of chromium(VI) and phenanthrene on the stem lengths of mung beans, pakchoi cabbage, and rice was 192, 173, and 279 mg kg(-1), respectively, and 200, 205, and 271 mg kg(-1) for the fresh weights of the three plants. The single and combined exposure of soil to chromium(VI) and phenanthrene had deleterious effects on plants in the early stage of growth. Overall, pakchoi cabbage was more sensitive than mung beans and rice. The two pollutants exerted synergistic effects on the stem lengths and above-ground fresh weights of both mung beans and rice but antagonistic effects on pakchoi cabbage. The results of this study also suggested pakchoi cabbage as a sensitive indicator of soil pollution. PMID

  11. Differential Properties of Human ALP+ Periodontal Ligament Stem Cells vs Their ALP- Counterparts

    PubMed Central

    Tran, Quynh T; El-Ayachi, Ikbale; Bhatti, Fazal-Ur-Rehman; Bahabri, Rayan; Al-Habib, Mey; Huang, George TJ

    2015-01-01

    Characterizing subpopulations of stem cells is important to understand stem cell properties. Tissue-nonspecific alkaline phosphatase (ALP) is associated with mineral tissue forming cells as well as stem cells. Information regarding ALP subpopulation of human periodontal ligament stem cells (hPDLSCs) is limited. In the present study, we examined ALP+ and ALP− hPDLSC subpopulations, their surface markers STRO-1 and CD146, and the expression of stemness genes at various cell passages. We found that ALP+ subpopulation had higher levels of STRO-1 (30.6 ± 5.6%) and CD146 (90.4 ± 3.3%) compared to ALP− (STRO-1: 0.5 ± 0.1%; CD146: 75.3 ± 7.2%). ALP+ cells expressed significantly higher levels of stemness associated genes, NANOG, OCT4 and SOX than ALP− cells at low cell passages of 2-3 (p<0.05). ALP+ and ALP− cells had similar osteogenic, chondrogenic and neurogenic potential while ALP−, not ALP+ cells, lacked adipogenic potential. Upon continuous culturing and passaging, ALP+ continued to express higher stemness genes and STRO-1 and CD146 than ALP− cells at ≥passage 19. Under conditions (over-confluence and vitamin C treatment) when ALP+ subpopulation was increased, the stemness gene levels of ALP+ was no longer significantly higher than those in ALP− cells. In conclusion, ALP+ hPDLSCs possess differential properties from their ALP− counterparts. PMID:26807329

  12. Stearoyl-acyl-carrier-protein desaturase from higher plants is structurally unrelated to the animal and fungal homologs

    SciTech Connect

    Shanklin, J.; Somerville, C. )

    1991-03-15

    Stearoyl-acyl-carrier-protein (ACP) desaturase was purified to homogeneity from avocado mesocarp, and monospecific polyclonal antibodies directed against the protein were used to isolate full-length cDNA clones from Ricinus communis (castor) seed and Cucumis sativus (cucumber). The nucleotide sequence of the castor clone pRCD1 revealed an open reading frame of 1.2 kilobases encoding a 396-amino acid protein of 45 kDa. The cucumber clone pCSD1 encoded a homologous 396-amino acid protein with 88% amino acid identity to the castor clone. Expression of pRCD1 in Saccharomyces cerevisiae resulted in the accumulation of a functional stearoyl-ACP desaturase, demonstrating that the introduction of this single gene product was sufficient to confer soluble desaturase activity to yeast. There was a 48-residue region of 29% amino acid sequence identity between residues 53 and 101 of the castor desaturase and the proximal border of the dehydratase region of the fatty acid synthase from yeast. Stearoyl-ACP mRNA was present at substantially higher levels in developing seeds than in leaf and root tissue, suggesting that expression of the {Delta}{sup 9} desaturase is developmentally regulated.

  13. Stearoyl-acyl-carrier-protein desaturase from higher plants is structurally unrelated to the animal and fungal homologs.

    PubMed Central

    Shanklin, J; Somerville, C

    1991-01-01

    Stearoyl-acyl-carrier-protein (ACP) desaturase (EC 1.14.99.6) was purified to homogeneity from avocado mesocarp, and monospecific polyclonal antibodies directed against the protein were used to isolate full-length cDNA clones from Ricinus communis (castor) seed and Cucumis sativus (cucumber). The nucleotide sequence of the castor clone pRCD1 revealed an open reading frame of 1.2 kilobases encoding a 396-amino acid protein of 45 kDa. The cucumber clone pCSD1 encoded a homologous 396-amino acid protein with 88% amino acid identity to the castor clone. Expression of pRCD1 in Saccharomyces cerevisiae resulted in the accumulation of a functional stearoyl-ACP desaturase, demonstrating that the introduction of this single gene product was sufficient to confer soluble desaturase activity to yeast. There was no detectable identity between the deduced amino acid sequences of the castor delta 9-stearoyl-ACP desaturase and either the delta 9-stearoyl-CoA desaturase from rat or yeast or the delta 12 desaturase from Synechocystis, suggesting that these enzymes may have evolved independently. However, there was a 48-residue region of 29% amino acid sequence identity between residues 53 and 101 of the castor desaturase and the proximal border of the dehydratase region of the fatty acid synthase from yeast. Stearoyl-ACP mRNA was present at substantially higher levels in developing seeds than in leaf and root tissue, suggesting that expression of the delta 9 desaturase is developmentally regulated. Images PMID:2006187

  14. Can Stress-Induced Biochemical Differences drive Variation in the Hydrogen Isotope Composition of Leaf Wax n-Alkanes from Terrestrial Higher Plants?

    NASA Astrophysics Data System (ADS)

    Eley, Y.; Pedentchouk, N.; Dawson, L.

    2014-12-01

    Recent research has identified that interspecies variation in leaf wax n-alkane 2H/1H from plants growing at the same geographical location can exceed 100‰. These differences cannot easily be explained by mechanisms that influence the isotopic composition of leaf water. Biochemical processes are therefore likely to drive some of this variability. Currently, however, little is known about the relative importance of different biochemical processes in shaping n-alkane hydrogen isotope composition. To explore this issue, we combined n-alkane δ2H analysis with measurements of: (i) the percentage content of leaf C and N; and (ii) foliar δ15N, from seven plants growing at Stiffkey salt marsh, Norfolk, UK. These species differ biochemically in respect of the protective compounds they produce under salt or water stressed conditions, with monocots generally producing more carbohydrates, and dicots producing more nitrogenous compounds. We found that monocots had higher %C, while dicots had higher %N and 15N-enriched leaf tissue. We identified a systematic relationship between the nature of the dominant protective compound produced (carbohydrate vs. nitrogenous) and n-alkane 2H/1H: species with a greater proportion of carbohydrates have more negative δ2H values. These findings might imply that shifts in the relative contribution of H to pyruvate from NADPH (2H-depleted) and recycled carbohydrates (2H-enriched) can influence n-alkane δ2H. The 2H-depletion of monocot n-alkanes relative to dicots may therefore be due to a greater proportion of NADPH-derived H incorporated into pyruvate because of their enhanced demand for carbohydrates. The production of protective compounds in plant species is a common response to a range of abiotic stresses (e.g. high UV irradiation, drought, salinity, high/low temperature). Species-specific biochemical responses to stress could therefore influence n-alkane 2H/1H across a range of habitats. This study highlights the importance of detailed

  15. Solution NMR and molecular dynamics reveal a persistent alpha helix within the dynamic region of PsbQ from photosystem II of higher plants

    PubMed Central

    Rathner, Petr; Rathner, Adriana; Horničáková, Michaela; Wohlschlager, Christian; Chandra, Kousik; Kohoutová, Jaroslava; Ettrich, Rüdiger; Wimmer, Reinhard

    2015-01-01

    ABSTRACT The extrinsic proteins of photosystem II of higher plants and green algae PsbO, PsbP, PsbQ, and PsbR are essential for stable oxygen production in the oxygen evolving center. In the available X‐ray crystallographic structure of higher plant PsbQ residues S14‐Y33 are missing. Building on the backbone NMR assignment of PsbQ, which includes this “missing link”, we report the extended resonance assignment including side chain atoms. Based on nuclear Overhauser effect spectra a high resolution solution structure of PsbQ with a backbone RMSD of 0.81 Å was obtained from torsion angle dynamics. Within the N‐terminal residues 1–45 the solution structure deviates significantly from the X‐ray crystallographic one, while the four‐helix bundle core found previously is confirmed. A short α‐helix is observed in the solution structure at the location where a β‐strand had been proposed in the earlier crystallographic study. NMR relaxation data and unrestrained molecular dynamics simulations corroborate that the N‐terminal region behaves as a flexible tail with a persistent short local helical secondary structure, while no indications of forming a β‐strand are found. Proteins 2015; 83:1677–1686. © 2015 The Authors. Proteins: Structure, Function, and Bioinformatics Published by Wiley Periodicals, Inc. PMID:26138376

  16. Solution NMR and molecular dynamics reveal a persistent alpha helix within the dynamic region of PsbQ from photosystem II of higher plants.

    PubMed

    Rathner, Petr; Rathner, Adriana; Horničáková, Michaela; Wohlschlager, Christian; Chandra, Kousik; Kohoutová, Jaroslava; Ettrich, Rüdiger; Wimmer, Reinhard; Müller, Norbert

    2015-09-01

    The extrinsic proteins of photosystem II of higher plants and green algae PsbO, PsbP, PsbQ, and PsbR are essential for stable oxygen production in the oxygen evolving center. In the available X-ray crystallographic structure of higher plant PsbQ residues S14-Y33 are missing. Building on the backbone NMR assignment of PsbQ, which includes this "missing link", we report the extended resonance assignment including side chain atoms. Based on nuclear Overhauser effect spectra a high resolution solution structure of PsbQ with a backbone RMSD of 0.81 Å was obtained from torsion angle dynamics. Within the N-terminal residues 1-45 the solution structure deviates significantly from the X-ray crystallographic one, while the four-helix bundle core found previously is confirmed. A short α-helix is observed in the solution structure at the location where a β-strand had been proposed in the earlier crystallographic study. NMR relaxation data and unrestrained molecular dynamics simulations corroborate that the N-terminal region behaves as a flexible tail with a persistent short local helical secondary structure, while no indications of forming a β-strand are found. PMID:26138376

  17. Use of Protein Cross-Linking and Radiolytic Labeling To Elucidate the Structure of PsbO within Higher-Plant Photosystem II.

    PubMed

    Mummadisetti, Manjula P; Frankel, Laurie K; Bellamy, Henry D; Sallans, Larry; Goettert, Jost S; Brylinski, Michal; Bricker, Terry M

    2016-06-14

    We have used protein cross-linking with the zero-length cross-linker 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide, and radiolytic footprinting coupled with high-resolution tandem mass spectrometry, to examine the structure of higher-plant PsbO when it is bound to Photosystem II. Twenty intramolecular cross-linked residue pairs were identified. On the basis of this cross-linking data, spinach PsbO was modeled using the Thermosynechococcus vulcanus PsbO structure as a template, with the cross-linking distance constraints incorporated using the MODELLER program. Our model of higher-plant PsbO identifies several differences between the spinach and cyanobacterial proteins. The N-terminal region is particularly interesting, as this region has been suggested to be important for oxygen evolution and for the specific binding of PsbO to Photosystem II. Additionally, using radiolytic mapping, we have identified regions on spinach PsbO that are shielded from the bulk solvent. These domains may represent regions on PsbO that interact with other components, as yet unidentified, of the photosystem. PMID:27203407

  18. The SCUBA-2 Cosmology Legacy Survey: Multiwavelength Counterparts to 103 Submillimeter Galaxies in the UKIDSS-UDS Field

    NASA Astrophysics Data System (ADS)

    Chen, Chian-Chou; Smail, Ian; Ivison, Rob J.; Arumugam, Vinodiran; Almaini, Omar; Conselice, Christopher J.; Geach, James E.; Hartley, Will G.; Ma, Cheng-Jiun; Mortlock, Alice; Simpson, Chris; Simpson, James M.; Swinbank, A. Mark; Aretxaga, Itziar; Blain, Andrew; Chapman, Scott C.; Dunlop, James S.; Farrah, Duncan; Halpern, Mark; Michałowski, Michał J.; van der Werf, Paul; Wilkinson, Aaron; Zavala, Jorge A.

    2016-04-01

    We present multiwavelength identifications for the counterparts of 1088 submillimeter sources detected at 850 μm in the SCUBA-2 Cosmology Legacy Survey study of the UKIRT Infrared Deep Sky Survey-Ultra-Deep Survey (UDS) field. By utilizing an Atacama Large Millimeter Array (ALMA) pilot study on a subset of our bright SCUBA-2 sample as a training set, along with the deep optical-near-infrared (OIR) data available in this field, we develop a novel technique, Optical-IR Triple Color (OIRTC), using z - K, K - [3.6], [3.6] - [4.5] colors to select the candidate submillimeter galaxy (SMG) counterparts. By combining radio identification and the OIRTC technique, we find counterpart candidates for 80% of the Class = 1 ≥ 4σ SCUBA-2 sample, defined as those that are covered by both radio and OIR imaging and the base sample for our scientific analyses. Based on the ALMA training set, we expect the accuracy of these identifications to be 82% ± 20%, with a completeness of 69% ± 16%, essentially as accurate as the traditional p-value technique but with higher completeness. We find that the fraction of SCUBA-2 sources having candidate counterparts is lower for fainter 850 μm sources, and we argue that for follow-up observations sensitive to SMGs with S850 ≳ 1 mJy across the whole ALMA beam, the fraction with multiple counterparts is likely to be >40% for SCUBA-2 sources at S850 ≳ 4 mJy. We find that the photometric redshift distribution for the SMGs is well fit by a lognormal distribution, with a median redshift of z = 2.3 ± 0.1. After accounting for the sources without any radio and/or OIRTC counterpart, we estimate the median redshift to be z = 2.6 ± 0.1 for SMGs with S850 > 1 mJy. We also use this new large sample to study the clustering of SMGs and the far-infrared properties of the unidentified submillimeter sources by stacking their Herschel SPIRE far-infrared emission.

  19. Lutein is needed for efficient chlorophyll triplet quenching in the major LHCII antenna complex of higher plants and effective photoprotection in vivo under strong light

    PubMed Central

    Dall'Osto, Luca; Lico, Chiara; Alric, Jean; Giuliano, Giovanni; Havaux, Michel; Bassi, Roberto

    2006-01-01

    Background Lutein is the most abundant xanthophyll in the photosynthetic apparatus of higher plants. It binds to site L1 of all Lhc proteins, whose occupancy is indispensable for protein folding and quenching chlorophyll triplets. Thus, the lack of a visible phenotype in mutants lacking lutein has been surprising. Results We have re-assessed the lut2.1 phenotypes through biochemical and spectroscopic methods. Lhc proteins from the lut2.1 mutant compensate the lack of lutein by binding violaxanthin in sites L1 and L2. This substitution reduces the capacity for regulatory mechanisms such as NPQ, reduces antenna size, induces the compensatory synthesis of Antheraxanthin + Zeaxanthin, and prevents the trimerization of LHCII complexes. In vitro reconstitution shows that the lack of lutein per se is sufficient to prevent trimerization. lut2.1 showed a reduced capacity for state I – state II transitions, a selective degradation of Lhcb1 and 2, and a higher level of photodamage in high light and/or low temperature, suggesting that violaxanthin cannot fully restore chlorophyll triplet quenching. In vitro photobleaching experiments and time-resolved spectroscopy of carotenoid triplet formation confirmed this hypothesis. The npq1lut2.1 double mutant, lacking both zeaxanthin and lutein, is highly susceptible to light stress. Conclusion Lutein has the specific property of quenching harmful 3Chl* by binding at site L1 of the major LHCII complex and of other Lhc proteins of plants, thus preventing ROS formation. Substitution of lutein by violaxanthin decreases the efficiency of 3Chl* quenching and causes higher ROS yield. The phenotype of lut2.1 mutant in low light is weak only because rescuing mechanisms of photoprotection, namely zeaxanthin synthesis, compensate for the ROS production. We conclude that zeaxanthin is effective in photoprotection of plants lacking lutein due to the multiple effects of zeaxanthin in photoprotection, including ROS scavenging and direct quenching

  20. Use resources of human exometabolites of different oxidation levels for higher plants cultivation on the soil-like substrate as applied to closed ecosystems

    NASA Astrophysics Data System (ADS)

    Tikhomirov, Alexander A.; Kudenko, Yurii; Ushakova, Sofya; Tirranen, Lyalya; Gribovskaya, Illiada; Gros, Jean-Bernard; Lasseur, Christophe

    The technology of ‘wet incineration' of human exometabolites and inedible plants biomass by means of H2 O2 in alternating electromagnetic field to increase a closure of mass exchange processes in bioregenerative life support systems (BLSS) was developed at the Institute of Biophysics of the Siberian Branch of Russian Academy of Sciences (Krasnoyarsk, Russia). Human exometabolites mineralized can be used in a nutrient solution for plants cultivation in the BLSS phototrophic link. The objective of the given work appears to be the study of use resources of human exometabolites of different oxidation levels processed by the abovementioned method for higher plants cultivation on the soil-like substrate (SLS). The mineralized human wastes were tested for the purpose of their sterility. Then the effect of human exometabolites of different oxidation levels both on wheat productivity and on the SLS microflora composition was examined. The SLS extract with a definite amount of human mineralized wastes was used as an irrigation solution. The conducted experiments demonstrated that the H2 O2 decreasing to 1 ml on 1 g of feces and to 0.25 ml on 1 ml of urine had not affected the sterility of mineralized human wastes. Wheat cultivation on the SLS with the addition in an irrigation solution of mineralized human wastes in the amount simulating 1/6 of a daily human diet showed the absence of basic dependence of plants productivity on oxidation level of human exometabolites. Yet the analysis of the microflora composition of the irrigation solutions demonstrated its dependence on the oxidation level of the exometabolites introduced. The amount of yeast-like fungi increased in 20 times in the solutions containing less oxidized exometabolites in comparison with the variant in which the human wastes were subjected to a full-scale oxidation. Besides, the solutions with less oxidized exometabolites displayed a bigger content of plant pathogenic bacteria and denitrifies. Consequently the

  1. Fat Metabolism in Higher Plants

    PubMed Central

    Harwood, J. L.; Stumpf, P. K.

    1970-01-01

    To understand more fully organelle membrane assemblage, the synthesis of the first fatty acids by the germinating pea, Pisum sativum, was studied by the incorporation of either tritiated water or acetate-1-14C into lipids by the intact, initially dry seed. After a lag phase, labeling proceeded linearly. This lag phase ended when uptake of water had increased the seed weight to 185% of its original weight. The first fatty acids synthesized were palmitic and stearic followed shortly after by long chain saturated fatty acids (C20-C26). The synthesis of very long chain acids was consistently characteristic of several other seeds in early stages of germination. The majority of the radioactive acids were present in phospholipids and were localized in particulate fractions. The acyl components of phosphatidyl glycerol were highly labeled. The very long chain acids were found predominantly in the waxes. Pulse labeling indicated little turnover of the labeled fatty acids. Evidence is presented indicating that the enzymes for fatty acid synthesis are already present in the dry seed and participate in the synthesis of fatty acids once a critical water content of the seed is achieved. PMID:16657495

  2. Recycling efficiencies of C,H,O,N,S, and P elements in a biological life support system based on micro-organisms and higher plants

    NASA Astrophysics Data System (ADS)

    Gros, J. B.; Poughon, L.; Lasseur, C.; Tikhomirov, A. A.

    MELiSSA is a microorganism based artificial ecosystem conceived as a tool for understanding the behavior of ecosystems and developing the technology for future Manned Space Missions. MELiSSA is composed of four compartments colonized by the microorganisms required by the function of this ecosystem : breakdown of waste produced by men, regeneration of atmosphere and biosynthesis of edible biomass. This paper reports the mass balance description of a Biological Life Support System composed of the MELiSSA loop and of a Higher Plant Compartment working in parallel with the photosynthetic Spirulina compartment producing edible biomass. The recycling efficiencies of the system are determined and compared for various working conditions of the MELiSSA loop with or without the HPC.

  3. [Graviresponse in higher plants and its regulation in molecular bases: relevance to growth and development, and auxin polar transport in etiolated pea seedlings].

    PubMed

    Ueda, Junichi; Miyamoto, Kensuke

    2003-08-01

    We review the graviresponse under true and simulated microgravity conditions on a clinostat in higher plants, and its regulation in molecular bases, especially on the aspect of auxin polar transport in etiolated pea (Pisum sativum L. cv. Alaska) seedlings which were the plant materials subjected to STS-95 space experiments. True and simulated microgravity conditions substantially affected growth and development in etiolated pea seedlings, especially the direction of growth of stems and roots, resulting in automorphosis. In etiolated pea seedlings grown in space, epicotyls were the most oriented toward the direction far from the cotyledons, and roots grew toward the aerial space of Plant Growth Chamber. Automorphosis observed in space were well simulated by a clinorotation on a 3-dimensional clinostat and also phenocopied by the application of auxin polar transport inhibitors of 2,3,5-triiodobenzoic acid, N-(1-naphtyl)phthalamic acid and 9-hydroxyfluorene-9-carboxylic acid. Judging from the results described above together with the fact that activities of auxin polar transport in epicotyls of etiolated pea seedlings grown in space substantially were reduced, auxin polar transport seems to be closely related to automorphosis. Strenuous efforts to learn in molecular levels how gravity contributes to the auxin polar transport in etiolated pea epicotyls resulted in successful identification of PsPIN2 and PsAUX1 genes located in plasma membrane which products are considered to be putative efflux and influx carriers of auxin, respectively. Based on the results of expression of PsPIN2 and PsAUX1 genes under various gravistimulations, a possible role of PsPIN2 and PsAUX1 genes for auxin polar transport in etiolated pea seedlings will be discussed. PMID:14555809

  4. Water adsorption and dissociation on Ni(110): How is it different from its close packed counterparts?

    SciTech Connect

    Seenivasan, H.; Tiwari, Ashwani K.

    2014-05-07

    Water adsorption and dissociation on Ni(110) surface is studied in detail and compared with its close packed counterparts using density functional theory calculations. Water adsorption occurs on the top site as found on Ni(100) and Ni(111) but the adsorption is stronger on Ni(110). H and OH preferably adsorb on the short bridge sites (brgshort) opposed to hollow sites on (100) and (111) surfaces. Energy barriers for water molecule dissociation on Ni(110) as obtained from the transition state (TS) calculations were low compared to other Ni low indexed surfaces. TS geometries at different positions of the lattice coordinate, Q, were obtained to study the effect of surface temperature on dissociation of H{sub 2}O molecules. These calculations revealed that second layer atoms were also involved in the TS. Dissociation probabilities are obtained using a semi-classical approximation by sampling Q for a Boltzmann distribution at different temperatures. Results showed that the increasing surface temperature significantly increases the dissociation probabilities at lower energies and saturates near the barrier for dissociation. Although the contribution from both top and second layers is similar at low surface temperatures, motion of top layer atoms contribute more towards dissociation probability at higher surface temperatures. Dissociation probabilities obtained are more than one order of magnitude higher than that on Ni(100) and Ni(111) surfaces suggesting Ni(110) to be more reactive among the low indexed Ni surfaces.

  5. Limited distribution of natural cyanamide in higher plants: occurrence in Vicia villosa subsp. varia, V. cracca, and Robinia pseudo-acacia.

    PubMed

    Kamo, Tsunashi; Endo, Mai; Sato, Masae; Kasahara, Ryohei; Yamaya, Hiroko; Hiradate, Syuntaro; Fujii, Yoshiharu; Hirai, Nobuhiro; Hirota, Mitsuru

    2008-03-01

    Cyanamide (NH2CN) has recently been proven to be a natural product, although it has been synthesized for over 100 years for agricultural and industrial purposes. The distribution of natural cyanamide appears to be limited, as indicated by our previous investigation of 101 weed species. In the present study, to investigate the distribution of natural cyanamide in Vicia species, we monitored the cyanamide contents in V. villosa subsp. varia, V. cracca, and V. amoena during their pre-flowering and flowering seasons. It was confirmed that V. cracca was superior to V. villosa subsp. varia in accumulating natural cyanamide, and that V. amoena was unable to biosynthesize this compound under laboratory condition examined. The localization of cyanamide in the leaves of V. villosa subsp. varia seedlings was also clarified. In a screening study to find cyanamide-biosynthesizing plants, only Robinia pseudo-acacia was found to contain cyanamide among 452 species of higher plants. We have investigated 553 species to date, but have so far found the ability to biosynthesize cyanamide in only three species, V. villosa subsp. varia, V. cracca and R. pseudo-acacia. PMID:18160082

  6. [High molecular weight protein detected in higher plant cells by antibodies against dynein is associated with vesicular organelles including Golgi apparatus].

    PubMed

    Shanina, N A; Lazareva, E M; Chentsov, Iu S; Smirnova, E A

    2008-01-01

    The cytoplasmic dynein is a multisubunit complex driving organelles along microtubules to their minus-end. We used antibodies against two functional domains (motor and microtubule-binding) of one of principal components of the complex--dynein heavy chain of slime mould Dictyostelium discoideum--to test root meristem cells of wheat Triticum aestivum. The antibodies reacted with a high molecular weight protein (> 500 kDa) in the total cell extract and the band recognized by the antibodies in plant extracts had a lower electrophoretic mobility than the high molecular weight band of mammalian dynein. Antibodies coupled to protein A-Sepharose precipitated the high molecular weight protein from the purified cell extracts. Immunocytochemical analysis demonstrated that the antigen recognized by antibodies against dynein heavy chains is associated with the vesicles whose localization depends on the cell cycle stage. The antigen-positive vesicles were localized to the perinuclear region in interphase and early prophase, to the spindle periphery and to spindle pole region during mitosis, and to the interzonal region in the period of fragmoplast and cell plate formation. Some antigen-positive vesicles also reacted with antibodies against Golgi protein markers. The obtained data indicate that higher plant cells contain a high molecular weight protein interacting with antibodies against the motor and microtubules-binding domains of Dictyostelium dynein heavy chain. The revealed antigen was associated with the vesicular structures in the cytoplasm including the Golgi apparatus. PMID:18409378

  7. Cross-linking Evidence for Multiple Interactions of the PsbP and PsbQ Proteins in a Higher Plant Photosystem II Supercomplex*

    PubMed Central

    Ido, Kunio; Nield, Jon; Fukao, Yoichiro; Nishimura, Taishi; Sato, Fumihiko; Ifuku, Kentaro

    2014-01-01

    The extrinsic subunits of membrane-bound photosystem II (PSII) maintain an essential role in optimizing the water-splitting reaction of the oxygen-evolving complex (OEC), even though they have undergone drastic change during the evolution of oxyphototrophs from symbiotic cyanobacteria to chloroplasts. Two specific extrinsic proteins, PsbP and PsbQ, bind to the lumenal surface of PSII in green plants and maintain OEC conformation and stabilize overall enzymatic function; however, their precise location has not been fully resolved. In this study, PSII-enriched membranes, isolated from spinach, were subjected to chemical cross-linking combined with release-reconstitution experiments. We observed direct interactions between PsbP and PsbE, as well as with PsbR. Intriguingly, PsbP and PsbQ were further linked to the CP26 and CP43 light-harvesting proteins. In addition, two cross-linked sites, between PsbP and PsbR, and that of PsbP and CP26, were identified by tandem mass spectrometry. These data were used to estimate the binding topology and location of PsbP, and the putative positioning of PsbQ and PsbR on the lumenal surface of the PSII. Our model gives new insights into the organization of PSII extrinsic subunits in higher plants and their function in stabilizing the OEC of the PSII supercomplex. PMID:24914208

  8. Use of protein cross-linking and radiolytic footprinting to elucidate PsbP and PsbQ interactions within higher plant Photosystem II.

    PubMed

    Mummadisetti, Manjula P; Frankel, Laurie K; Bellamy, Henry D; Sallans, Larry; Goettert, Jost S; Brylinski, Michal; Limbach, Patrick A; Bricker, Terry M

    2014-11-11

    Protein cross-linking and radiolytic footprinting coupled with high-resolution mass spectrometry were used to examine the structure of PsbP and PsbQ when they are bound to Photosystem II. In its bound state, the N-terminal 15-amino-acid residue domain of PsbP, which is unresolved in current crystal structures, interacts with domains in the C terminus of the protein. These interactions may serve to stabilize the structure of the N terminus and may facilitate PsbP binding and function. These interactions place strong structural constraints on the organization of PsbP when associated with the Photosystem II complex. Additionally, amino acid residues in the structurally unresolved loop 3A domain of PsbP ((90)K-(107)V), (93)Y and (96)K, are in close proximity (≤ 11.4 Å) to the N-terminal (1)E residue of PsbQ. These findings are the first, to our knowledge, to identify a putative region of interaction between these two components. Cross-linked domains within PsbQ were also identified, indicating that two PsbQ molecules can interact in higher plants in a manner similar to that observed by Liu et al. [(2014) Proc Natl Acad Sci 111(12):4638-4643] in cyanobacterial Photosystem II. This interaction is consistent with either intra-Photosystem II dimer or inter-Photosystem II dimer models in higher plants. Finally, OH(•) produced by synchrotron radiolysis of water was used to oxidatively modify surface residues on PsbP and PsbQ. Domains on the surface of both protein subunits were resistant to modification, indicating that they were shielded from water and appear to define buried regions that are in contact with other Photosystem II components. PMID:25349426

  9. Comparison of Scores on the WAIS and Its Puerto Rican Counterpart, Escala de Inteligencia Wechsler para Adultos, in an Institutionalized Latin American Psychiatric Population.

    ERIC Educational Resources Information Center

    Davis, Todd McLin; Rodriguez, Vene L.

    1979-01-01

    Compared vocabulary and block design subtests of the Wechsler Adult Intelligence Scale (WAIS) and its Puerto Rican counterpart, the Escala de Inteligencia Wechsler para Adultos (EIWA), in hospitalized Latins and Trans-Caribbean Blacks. EIWA scores were significantly higher than WAIS scores. Equivalence of EIWA and WAIS estimates is questioned.…

  10. VizieR Online Data Catalog: Selecting IRAC counterparts to SMGs (Alberts+, 2013)

    NASA Astrophysics Data System (ADS)

    Alberts, S.; Wilson, G. W.; Lu, Y.; Johnson, S.; Yun, M. S.; Scott, K. S.; Pope, A.; Aretxaga, I.; Ezawa, H.; Hughes, D. H.; Kawabe, R.; Kim, S.; Kohno, K.; Oshima, T.

    2014-05-01

    We present a new submm/mm galaxy counterpart identification technique which builds on the use of Spitzer Infrared Array Camera (IRAC) colours as discriminators between likely counterparts and the general IRAC galaxy population. Using 102 radio- and Submillimeter Array-confirmed counterparts to AzTEC sources across three fields [Great Observatories Origins Deep Survey-North, -South and Cosmic Evolution Survey (COSMOS)], we develop a non-parametric IRAC colour-colour characteristic density distribution, which, when combined with positional uncertainty information via likelihood ratios, allows us to rank all potential IRAC counterparts around submillimetre galaxies (SMGs) and calculate the significance of each ranking via the reliability factor. We report all robust and tentative radio counterparts to SMGs, the first such list available for AzTEC/COSMOS, as well as the highest ranked IRAC counterparts for all AzTEC SMGs in these fields as determined by our technique. We demonstrate that the technique is free of radio bias and thus applicable regardless of radio detections. For observations made with a moderate beam size (~18"), this technique identifies ~85% of SMG counterparts. For much larger beam sizes (>~30"), we report identification rates of 33-49%. Using simulations, we demonstrate that this technique is an improvement over using positional information alone for observations with facilities such as AzTEC on the Large Millimeter Telescope and Submillimeter Common User Bolometer Array 2 on the James Clerk Maxwell Telescope. (3 data files).

  11. Higher sterol content regulated by CYP51 with concomitant lower phospholipid content in membranes is a common strategy for aluminium tolerance in several plant species.

    PubMed

    Wagatsuma, Tadao; Khan, Md Shahadat Hossain; Watanabe, Toshihiro; Maejima, Eriko; Sekimoto, Hitoshi; Yokota, Takao; Nakano, Takeshi; Toyomasu, Tomonobu; Tawaraya, Keitaro; Koyama, Hiroyuki; Uemura, Matsuo; Ishikawa, Satoru; Ikka, Takashi; Ishikawa, Akifumi; Kawamura, Takeshi; Murakami, Satoshi; Ueki, Nozomi; Umetsu, Asami; Kannari, Takayuki

    2015-02-01

    Several studies have shown that differences in lipid composition and in the lipid biosynthetic pathway affect the aluminium (Al) tolerance of plants, but little is known about the molecular mechanisms underlying these differences. Phospholipids create a negative charge at the surface of the plasma membrane and enhance Al sensitivity as a result of the accumulation of positively charged Al(3+) ions. The phospholipids will be balanced by other electrically neutral lipids, such as sterols. In the present research, Al tolerance was compared among pea (Pisum sativum) genotypes. Compared with Al-tolerant genotypes, the Al-sensitive genotype accumulated more Al in the root tip, had a less intact plasma membrane, and showed a lower expression level of PsCYP51, which encodes obtusifoliol-14α-demethylase (OBT 14DM), a key sterol biosynthetic enzyme. The ratio of phospholipids to sterols was higher in the sensitive genotype than in the tolerant genotypes, suggesting that the sterol biosynthetic pathway plays an important role in Al tolerance. Consistent with this idea, a transgenic Arabidopsis thaliana line with knocked-down AtCYP51 expression showed an Al-sensitive phenotype. Uniconazole-P, an inhibitor of OBT 14DM, suppressed the Al tolerance of Al-tolerant genotypes of maize (Zea mays), sorghum (Sorghum bicolor), rice (Oryza sativa), wheat (Triticum aestivum), and triticale (×Triticosecale Wittmark cv. Currency). These results suggest that increased sterol content, regulated by CYP51, with concomitant lower phospholipid content in the root tip, results in lower negativity of the plasma membrane. This appears to be a common strategy for Al tolerance among several plant species. PMID:25416794

  12. Representation of pheromones, interspecific signals, and plant odors in higher olfactory centers; mapping physiologically identified antennal-lobe projection neurons in the male heliothine moth

    PubMed Central

    Zhao, Xin-Cheng; Kvello, Pål; Løfaldli, Bjarte B.; Lillevoll, Siri C.; Mustaparta, Hanna; Berg, Bente G.

    2014-01-01

    The arrangement of anatomically separated systems for information about general and pheromone odorants is well documented at the initial levels of the olfactory pathway both in vertebrates and insects. In the primary olfactory center of the moth brain, for example, a few enlarged glomeruli situated dorsally, at the entrance of the antennal nerve, are devoted to information about female-produced substances whereas a set of more numerous ordinary glomeruli (OG) receives input about general odorants. Heliothine moths are particularly suitable for studying central chemosensory mechanisms not only because of their anatomically separated systems for plant odors and pheromones but also due to their use of female-produced substances in communication across the species. Thus, the male-specific system of heliothine moths includes two sub-arrangements, one ensuring attraction and mating behavior by carrying information about pheromones released by conspecifics, and the other inhibition of attraction via signal information emitted from heterospecifics. Based on previous tracing experiments, a general chemotopic organization of the male-specific glomeruli has been demonstrated in a number of heliothine species. As compared to the well explored organization of the moth antennal lobe (AL), demonstrating a non-overlapping representation of the biologically relevant stimuli, less is known about the neural arrangement residing at the following synaptic level, i.e., the mushroom body calyces and the lateral horn. In the study presented here, we have labeled physiologically characterized antennal-lobe projection neurons in males of the two heliothine species, Heliothis virescens and Helicoverpa assulta, for the purpose of mapping their target regions in the protocerebrum. In order to compare the representation of plant odors, pheromones, and interspecific signals in the higher brain regions of each species, we have created standard brain atlases and registered three-dimensional models

  13. Vacuum electromagnetic counterparts of binary black-hole mergers

    SciTech Connect

    Moesta, Philipp; Rezzolla, Luciano; Pollney, Denis; Palenzuela, Carlos; Lehner, Luis; Yoshida, Shin'ichirou

    2010-03-15

    As one step towards a systematic modeling of the electromagnetic (EM) emission from an inspiralling black hole binary we consider a simple scenario in which the binary moves in a uniform magnetic field anchored to a distant circumbinary disc. We study this system by solving the Einstein-Maxwell equations in which the EM fields are chosen with strengths consistent with the values expected astrophysically and treated as test fields. Our initial data consists of a series of binaries with spins aligned or antialigned with the orbital angular momentum and we study the dependence of gravitational and EM signals with different spin configurations. Overall we find that the EM radiation in the lowest l=2, m=2 multipole accurately reflects the gravitational one, with identical phase evolutions and amplitudes that differ only by a scaling factor. This is no longer true when considering higher l modes, for which the amplitude evolution of the scaled EM emission is slightly larger, while the phase evolutions continue to agree. We also compute the efficiency of the energy emission in EM waves and find that it scales quadratically with the total spin and is given by E{sub EM}{sup rad}/M{approx_equal}10{sup -15}(M/10{sup 8}M{sub {center_dot}}){sup 2}(B/10{sup 4}G){sup 2}, hence 13 orders of magnitude smaller than the gravitational energy for realistic magnetic fields. Although large in absolute terms, the corresponding luminosity is much smaller than the accretion luminosity if the system is accreting at near the Eddington rate. Most importantly, this EM emission is at frequencies of {approx}10{sup -4}(10{sup 8}M{sub {center_dot}}/M) Hz, which are well outside those accessible to astronomical radio observations. As a result, it is unlikely that the EM emission discussed here can be detected directly and simultaneously with the gravitational-wave one. However, indirect processes, driven by changes in the EM fields behavior could yield observable events. In particular we argue that

  14. Comparison of GC-MS, GC-MRM-MS, and GC × GC to characterise higher plant biomarkers in Tertiary oils and rock extracts

    NASA Astrophysics Data System (ADS)

    Eiserbeck, Christiane; Nelson, Robert K.; Grice, Kliti; Curiale, Joseph; Reddy, Christopher M.

    2012-06-01

    Higher plant biomarkers occur in various compound classes with an array of isomers that are challenging to separate and identify. Traditional one-dimensional (1D) gas chromatographic (GC) techniques achieved impressive results in the past, but have reached limitations in many cases. Comprehensive two-dimensional gas chromatography (GC × GC) either coupled to a flame ionization detector (GC × GC-FID) or time-of-flight mass spectrometer (GC × GC-TOFMS) is a powerful tool to overcome the challenges of 1D GC, such as the resolution of unresolved complex mixture (UCM). We studied a number of Tertiary, terrigenous oils, and source rocks from the Arctic and Southeast Asia, with special focus on angiosperm biomarkers, such as oleanoids and lupanoids. Different chromatographic separation and detection techniques such as traditional 1D GC-MS, metastable reaction monitoring (GC-MRM-MS), GC × GC-FID, and GC × GC-TOFMS are compared and applied to evaluate the differences and advantages in their performance for biomarker identification. The measured 22S/(22S + 22R) homohopane ratios for all applied techniques were determined and compare exceptionally well (generally between 2% and 10%). Furthermore, we resolved a variety of angiosperm-derived compounds that co-eluted using 1D GC techniques, demonstrating the superior separation power of GC × GC for these biomarkers, which indicate terrigenous source input and Cretaceous or younger ages. Samples of varying thermal maturity and biodegradation contain higher plant biomarkers from various stages of diagenesis and catagenesis, which can be directly assessed in a GC × GC chromatogram. The analysis of whole crude oils and rock extracts without loss in resolution enables the separation of unstable compounds that are prone to rearrangement (e.g. unsaturated triterpenoids such as taraxer-14-ene) when exposed to fractionation techniques like molecular sieving. GC × GC-TOFMS is particularly valuable for the successful separation of

  15. Sense Transgene-Induced Post-Transcriptional Gene Silencing in Tobacco Compromises the Splicing of Endogenous Counterpart Genes

    PubMed Central

    Shin, Mi-Rae; Natsuume, Masaya; Matsumoto, Takashi; Hanaoka, Mitsumasa; Imai, Misaki; Iijima, Ken; Oka, Shin-ichiro; Adachi, Eri; Kodama, Hiroaki

    2014-01-01

    Sense transgene-induced post-transcriptional gene silencing (S-PTGS) is thought to be a type of RNA silencing in which ARGONAUTE1 directs the small interfering RNA (siRNA)-mediated cleavage of a target mRNA in the cytoplasm. Here, we report that the altered splicing of endogenous counterpart genes is a main cause for the reduction of their mature mRNA levels. After the S-PTGS of a tobacco endoplasmic reticulum ω-3 fatty acid desaturase (NtFAD3) gene, 3′-truncated, polyadenylated endo-NtFAD3 transcripts and 5′-truncated, intron-containing endo-NtFAD3 transcripts were detected in the total RNA fraction. Although transcription proceeded until the last exon of the endogenous NtFAD3 gene, intron-containing NtFAD3 transcripts accumulated in the nucleus of the S-PTGS plants. Several intron-containing NtFAD3 transcripts harboring most of the exon sequences were generated when an endogenous silencing suppressor gene, rgs-CaM, was overexpressed in the S-PTGS plants. These intron-containing NtFAD3 splice variants were generated in the presence of NtFAD3 siRNAs that are homologous to the nucleotide sequences of these splice variants. The results of this study indicate that the inhibition of endo-NtFAD3 gene expression is primarily directed via the alteration of splicing and not by cytoplasmic slicer activity. Our results suggest that the transgene and intron-containing endogenous counterpart genes are differentially suppressed in S-PTGS plants. PMID:24586294

  16. THE "X" FACTOR: Why Female Athletes Have a Higher Rate of ACL Injury than Their Male Counterparts

    ERIC Educational Resources Information Center

    Washington, James

    2012-01-01

    Sports have become an integral part of the developmental experience of many of today's youth. Since the implementation of Title IX, more young girls and women have begun to play sports and see those sports as a possible career path. Tennis, basketball and soccer all have professional sports leagues for women, and many more sports offer women the…

  17. Search for Electromagnetic Counterparts to LIGO-Virgo Candidates: Expanded Very Large Array Observations

    NASA Technical Reports Server (NTRS)

    Lazio, Joseph; Keating, Katie; Jenet, F. A.; Kassim, N. E.

    2011-01-01

    This paper summarizes a search for radio wavelength counterparts to candidate gravitational wave events. The identification of an electromagnetic counterpart could provide a more complete understanding of a gravitational wave event, including such characteristics as the location and the nature of the progenitor. We used the Expanded Very Large Array (EVLA) to search six galaxies which were identified as potential hosts for two candidate gravitational wave events. We summarize our procedures and discuss preliminary results.

  18. ER Import Sites and Their Relationship to ER Exit Sites: A New Model for Bidirectional ER-Golgi Transport in Higher Plants.

    PubMed

    Lerich, Alexander; Hillmer, Stefan; Langhans, Markus; Scheuring, David; van Bentum, Paulien; Robinson, David G

    2012-01-01

    Per definition, ER exit sites are COPII vesiculation events at the surface of the ER and in higher plants are only visualizable in the electron microscope through cryofixation techniques. Fluorescent COPII labeling moves with Golgi stacks and locates to the interface between the ER and the Golgi. In contrast, the domain of the ER where retrograde COPI vesicles fuse, i.e., ER import sites (ERIS), has remained unclear. To identify ERIS we have employed ER-located SNAREs and tethering factors. We screened several SNAREs (SYP81, the SYP7 family, and USE1) to find a SNARE whose overexpression did not disrupt ER-Golgi traffic and which gave rise to discrete fluorescent punctae when expressed with an XFP tag. Only the Qc-SNARE SYP72 fulfilled these criteria. When coexpressed with SYP72-YFP, both the type I-membrane protein RFP-p24δ5 and the luminal marker CFP-HDEL whose ER localization are due to an efficient COPI-mediated recycling, form nodules along the tubular ER network. SYP72-YFP colocalizes with these nodules which are not seen when RFP-p24δ5 or CFP-HDEL is expressed alone or when SYP72-YFP is coexpressed with a mutant form of RFP-p24δ5 that cannot exit the ER. SYP72-YFP does not colocalize with Golgi markers, except when the Golgi stacks are immobilized through actin depolymerization. Endogenous SYP7 SNAREs, also colocalize with immobilized COPII/Golgi. In contrast, XFP-tagged versions of plant homologs to TIP20 of the Dsl1 COPI-tethering factor complex, and the COPII-tethering factor p115 colocalize perfectly with Golgi stacks irrespective of the motile status. These data suggest that COPI vesicle fusion with the ER is restricted to periods when Golgi stacks are stationary, but that when moving both COPII and COPI vesicles are tethered and collect in the ER-Golgi interface. Thus, the Golgi stack and an associated domain of the ER thereby constitute a mobile secretory and recycling unit: a unique feature in eukaryotic cells. PMID:22876251

  19. Purification and characterization of high- and low-molecular-mass isoforms of phosphoenolpyruvate carboxylase from Chlamydomonas reinhardtii. Kinetic, structural and immunological evidence that the green algal enzyme is distinct from the prokaryotic and higher plant enzymes.

    PubMed Central

    Rivoal, J; Plaxton, W C; Turpin, D H

    1998-01-01

    Phosphoenolpyruvate carboxylase (PEPC) is a key enzyme in the supply of carbon skeletons for the assimilation of nitrogen by green algae. Two PEPC isoforms with respective native molecular masses of 400 (PEPC1) and 650 (PEPC2) kDa have been purified from Chlamydomonas reinhardtii CW-15 cc1883 (Chlorophyceae). SDS/PAGE, immunoblot and CNBr peptide-mapping analyses indicate the presence of the same 100 kDa PEPC catalytic subunit in both isoforms. PEPC1 is a homotetramer, whereas PEPC2 seems to be a complex between the PEPC catalytic subunit and other immunologically unrelated polypeptides of 50-70 kDa. Kinetic analyses indicate that these PEPC isoforms are (1) differentially regulated by pH, (2) activated by glutamine and dihydroxyacetone phosphate and (3) inhibited by glutamate, aspartate, 2-oxoglutarate and malate. These results are consistent with the current model for the regulation of anaplerotic carbon fixation in green algae, and demonstrate that green algal PEPCs are uniquely regulated by glutamine. Several techniques were used to assess the structural relationships between C. reinhardtii PEPC and the higher plant or prokaryotic enzyme. Immunoblot studies using anti-(green algal or higher plant PEPC) IgGs suggested that green algal (C. reinhardtii, Selenastrum minutum), higher plant (maize, banana fruit, tobacco) and prokaryotic (Synechococcus leopoliensis, Escherichia coli) PEPCs have little or no immunological relatedness. Moreover, the N-terminal amino acid sequence of the C. reinhardtii PEPC subunit did not have significant similarity to the highly conserved corresponding region in enzymes from higher plants, and CNBr cleavage patterns of green algal PEPCs were distinct from those of higher plant and cyanobacterial PEPCs. These results point to significant evolutionary divergence between green algal, higher plant and prokaryotic PEPCs. PMID:9512480

  20. Microbial Relatives of the Seed Storage Proteins of Higher Plants: Conservation of Structure and Diversification of Function during Evolution of the Cupin Superfamily

    PubMed Central

    Dunwell, Jim M.; Khuri, Sawsan; Gane, Paul J.

    2000-01-01

    This review summarizes the recent discovery of the cupin superfamily (from the Latin term “cupa,” a small barrel) of functionally diverse proteins that initially were limited to several higher plant proteins such as seed storage proteins, germin (an oxalate oxidase), germin-like proteins, and auxin-binding protein. Knowledge of the three-dimensional structure of two vicilins, seed proteins with a characteristic β-barrel core, led to the identification of a small number of conserved residues and thence to the discovery of several microbial proteins which share these key amino acids. In particular, there is a highly conserved pattern of two histidine-containing motifs with a varied intermotif spacing. This cupin signature is found as a central component of many microbial proteins including certain types of phosphomannose isomerase, polyketide synthase, epimerase, and dioxygenase. In addition, the signature has been identified within the N-terminal effector domain in a subgroup of bacterial AraC transcription factors. As well as these single-domain cupins, this survey has identified other classes of two-domain bicupins including bacterial gentisate 1,2-dioxygenases and 1-hydroxy-2-naphthoate dioxygenases, fungal oxalate decarboxylases, and legume sucrose-binding proteins. Cupin evolution is discussed from the perspective of the structure-function relationships, using data from the genomes of several prokaryotes, especially Bacillus subtilis. Many of these functions involve aspects of sugar metabolism and cell wall synthesis and are concerned with responses to abiotic stress such as heat, desiccation, or starvation. Particular emphasis is also given to the oxalate-degrading enzymes from microbes, their biological significance, and their value in a range of medical and other applications. PMID:10704478

  1. In vitro replication of mitochondrial plasmid mp1 from the higher plant Chenopodium album (L.): a remnant of bacterial rolling circle and conjugative plasmids?

    PubMed

    Backert, S; Kunnimalaiyaan, M; Börner, T; Nielsen, B L

    1998-12-11

    According to the endosymbiotic theory, mitochondrial genomes evolved from the chromosome of an alpha-proteobacterium-like ancestor and developed during evolution an extraordinary variation in size, structure and replication. We studied in vitro DNA replication of the mitochondrial circular plasmid mp1 (1309 bp) from the higher plant Chenopodium album (L.) as a model system that replicates in a manner reminiscent of bacterial rolling circle plasmids. Several mp1 subclones were tested for their ability to support DNA replication using a newly developed in vitro system. Neutral/neutral two-dimensional gel electrophoresis of the in vitro products revealed typical simple Y patterns of intermediates consistent with a rolling circle type of replication. Replication activity was very high for a BamHI-restricted total plasmid DNA clone, a 464 bp BamHI/KpnI fragment and a 363 bp BamHI/SmaI fragment. Further subcloning of a 148 bp BamHI/EcoRI fragment resulted in the strongest in vitro DNA replication activity, while a 1161 bp-template outside of this region resulted in a substantial loss of activity. Electron microscopic studies of in vitro DNA replication products from the highly active clones also revealed sigma-shaped molecules. These results support our in vivo data for the presence of a predominant replication origin between positions 628 and 776 on the plasmid map. This sequence shares homology with double-stranded rolling circle origin (dso) or transfer origin (oriT) nicking motifs from bacterial plasmids. mp1 is the first described rolling circle plasmid in eukaryotes. PMID:9837722

  2. RNA-binding proteins in plants: the tip of an iceberg?

    NASA Technical Reports Server (NTRS)

    Fedoroff, Nina V.; Federoff, N. V. (Principal Investigator)

    2002-01-01

    RNA-binding proteins, which are involved in the synthesis, processing, transport, translation, and degradation of RNA, are emerging as important, often multifunctional, cellular regulatory proteins. Although relatively few RNA-binding proteins have been studied in plants, they are being identified with increasing frequency, both genetically and biochemically. RNA-binding proteins that regulate chloroplast mRNA stability and translation in response to light and that have been elegantly analyzed in Clamydomonas reinhardtii have counterparts with similar functions in higher plants. Several recent reports describe mutations in genes encoding RNA-binding proteins that affect plant development and hormone signaling.

  3. The Chandra Xbootes Survey - IV: Mid-Infrared and Submillimeter Counterparts

    NASA Astrophysics Data System (ADS)

    Brown, Arianna; Mitchell-Wynne, Ketron; Cooray, Asantha R.; Nayyeri, Hooshang

    2016-06-01

    In this work, we use a Bayesian technique to identify mid-IR and submillimeter counterparts for 3,213 X-ray point sources detected in the Chandra XBoötes Survey so as to characterize the relationship between black hole activity and star formation in the XBoötes region. The Chandra XBoötes Survey is a 5-ks X-ray survey of the 9.3 square degree Boötes Field of the NOAO Deep Wide-Field Survey (NDWFS), a survey imaged from the optical to the near-IR. We use a likelihood ratio analysis on Spitzer-IRAC data taken from The Spitzer Deep, Wide-Field Survey (SDWFS) to determine mid-IR counterparts, and a similar method on Herschel-SPIRE sources detected at 250µm from The Herschel Multi-tiered Extragalactic Survey to determine the submillimeter counterparts. The likelihood ratio analysis (LRA) provides the probability that a(n) IRAC or SPIRE point source is the true counterpart to a Chandra source. The analysis is comprised of three parts: the normalized magnitude distributions of counterparts and background sources, and the radial probability distribution of the separation distance between the IRAC or SPIRE source and the Chandra source. Many Chandra sources have multiple prospective counterparts in each band, so additional analysis is performed to determine the identification reliability of the candidates. Identification reliability values lie between 0 and 1, and sources with identification reliability values ≥0.8 are chosen to be the true counterparts. With these results, we will consider the statistical implications of the sample's redshifts, mid-IR and submillimeter luminosities, and star formation rates.

  4. Does Decrease in Ribulose-1,5-Bisphosphate Carboxylase by Antisense RbcS Lead to a Higher N-Use Efficiency of Photosynthesis under Conditions of Saturating CO2 and Light in Rice Plants?

    PubMed

    Makino, A.; Shimada, T.; Takumi, S.; Kaneko, K.; Matsuoka, M.; Shimamoto, K.; Nakano, H.; Miyao-Tokutomi, M.; Mae, T.; Yamamoto, N.

    1997-06-01

    Rice (Oryza sativa L.) plants with decreased ribulose-1,5-bisphosphate carboxylase (Rubisco) were obtained by transformation with the rice rbcS antisense gene under the control of the rice rbcS promoter. The primary transformants were screened for the Rubisco to leaf N ratio, and the transformant with 65% wild-type Rubisco was selected as a plant set with optimal Rubisco content at saturating CO2 partial pressures for photosynthesis under conditions of high irradiance and 25[deg]C. This optimal Rubisco content was estimated from the amounts and kinetic constants of Rubisco and the gas-exchange data. The R1 selfed progeny of the selected transformant were grown hydroponically with different N concentrations. Rubisco content in the R1 population was distributed into two groups: 56 plants had about 65% wild-type Rubisco, whereas 23 plants were very similar to the wild type. Although the plants with decreased Rubisco showed 20% lower rates of light-saturated photosynthesis in normal air (36 Pa CO2), they had 5 to 15% higher rates of photosynthesis in elevated partial pressures of CO2, (100-115 Pa CO2) than the wild-type plants for a given leaf N content. We conclude that the rice plants with 65% wild-type Rubisco show a higher N-use efficiency of photosynthesis under conditions of saturating CO2 and high irradiance. PMID:12223722

  5. Daylily as a System to Study Effects of Space Flight on Plant Development

    NASA Technical Reports Server (NTRS)

    Krikorian, A. D.

    1985-01-01

    The intent of the protoplast experimentation was to develop a system which would permit work with wall less counterparts of totipotent free cells as a model for a fertilized egg cell. It is clear that the daylily system is becoming a valuable tool with which to study any number of basic phases of higher plant development. The system can now be studied from a number of perspectives. A system amenable to rigorous experimentation was developed and can be used as a point of departure for studying problems of development in the space environment. This will be a prelude to the studying of the effect of hypogravity on higher plant development.

  6. The conserved role of FtsH11 protease in protection of photosynthetic system from high temperature stress in higher plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    As sessile organisms, plants employ multiple mechanisms to cope with seasonal and daily temperature fluctuations associated with their habitats. AtFtsH11 protease gene was identified via map-based cloning as essential for Arabidopsis plant to survive at moderate high temperatures. There are 12 predi...

  7. Near-infrared counterparts to the Galactic Bulge Survey X-ray source population

    NASA Astrophysics Data System (ADS)

    Greiss, S.; Steeghs, D.; Jonker, P. G.; Torres, M. A. P.; Maccarone, T. J.; Hynes, R. I.; Britt, C. T.; Nelemans, G.; Gänsicke, B. T.

    2014-03-01

    We report on the near-infrared matches, drawn from three surveys, to the 1640 unique X-ray sources detected by Chandra in the Galactic Bulge Survey (GBS). This survey targets faint X-ray sources in the bulge, with a particular focus on accreting compact objects. We present all viable counterpart candidates and associate a false alarm probability (FAP) to each near-infrared match in order to identify the most likely counterparts. The FAP takes into account a statistical study involving a chance alignment test, as well as considering the positional accuracy of the individual X-ray sources. We find that although the star density in the bulge is very high, ˜90 per cent of our sources have an FAP <10 per cent, indicating that for most X-ray sources, viable near-infrared counterparts candidates can be identified. In addition to the FAP, we provide positional and photometric information for candidate counterparts to ˜95 per cent of the GBS X-ray sources. This information in combination with optical photometry, spectroscopy and variability constraints will be crucial to characterize and classify secure counterparts.

  8. Life-cycle fossil energy consumption and greenhouse gas emissions of bioderived chemicals and their conventional counterparts.

    PubMed

    Adom, Felix; Dunn, Jennifer B; Han, Jeongwoo; Sather, Norm

    2014-12-16

    Biomass-derived chemical products may offer reduced environmental impacts compared to their fossil-derived counterparts and could improve profit margins at biorefineries when coproduced with higher-volume, lower-profit margin biofuels. It is important to assess on a life-cycle basis the energy and environmental impacts of these bioproducts as compared to conventional, fossil-derived products. We undertook a life-cycle analysis of eight bioproducts produced from either algal-derived glycerol or corn stover-derived sugars. Selected on the basis of technology readiness and market potential, the bioproducts are propylene glycol, 1,3-propanediol, 3-hydroxypropionic acid, acrylic acid, polyethylene, succinic acid, isobutanol, and 1,4-butanediol. We developed process simulations to obtain energy and material flows in the production of each bioproduct and examined sensitivity of these flows to process design assumptions. Conversion process data for fossil-derived products were based on the literature. Conversion process data were combined with upstream parameters in the Greenhouse gases, Regulated Emissions, and Energy use in Transportation (GREET) model to generate life-cycle greenhouse gas (GHG) emissions and fossil energy consumption (FEC) for each bioproduct and its corresponding petroleum-derived product. The bioproducts uniformly offer GHG emissions reductions compared to their fossil counterparts ranging from 39 to 86% on a cradle-to-grave basis. Similarly, FEC was lower for bioproducts than for conventional products. PMID:25380298

  9. Genetic and Prognostic Differences of Non-small Cell Lung Cancer between Elderly Patients and Younger Counterparts.

    PubMed

    Suda, Kenichi; Tomizawa, Kenji; Mizuuchi, Hiroshi; Ito, Simon; Kitahara, Hirokazu; Shimamatsu, Shinichiro; Kohno, Mikihiro; Yoshida, Tsukihisa; Okamoto, Tatsuro; Maehara, Yoshihiko; Yatabe, Yasushi; Mitsudomi, Tetsuya

    2012-12-01

    Many elderly patients suffer from lung cancers, but it is not clear if their lung cancers differ from those of younger patients. In this study, we compared genetic and prognostic characteristics of lung cancers of patients aged ≥75 years with those of patients aged ≤ 64 years. In the genetic analysis, we explored 292 surgically treated non-squamous cell lung cancers with known mutational status of epidermal growth factor (EGFR) and anaplastic lymphoma kinase (ALK). In the prognostic analysis, we retrospectively analyzed 405 surgically treated non-small cell lung cancers (NSCLCs) before the era of routine clinical application of post-surgical adjuvant chemotherapy. Postsurgical recurrence-free survival (RFS) was compared between elderly patients and younger counterparts. The genetic analysis showed elderly non-squamous cell lung cancer patients to have higher prevalence of EGFR mutations (53.1 % vs 42.0%, P = 0.15) and lower prevalence of the ALK translocation (0 % vs 4.5%, P = 0.23) than their younger counterparts. The prognostic analysis showed postsurgical RFS was similar between the elderly NSCLC patients and the younger patients. However in multivariate analysis, adjusting for gender, smoking status, pathological stage, and histology, elderly patients had significantly worse prognoses (HR 1.57, 95% CI, 1.08-2.29; P = 0.02) compared with younger patients. These results suggest differences in genetic and prognostic aspects between elderly lung cancer patients and younger lung cancer patients. PMID:23251849

  10. Genetic and Prognostic Differences of Non-small Cell Lung Cancer between Elderly Patients and Younger Counterparts

    PubMed Central

    Suda, Kenichi; Tomizawa, Kenji; Mizuuchi, Hiroshi; Ito, Simon; Kitahara, Hirokazu; Shimamatsu, Shinichiro; Kohno, Mikihiro; Yoshida, Tsukihisa; Okamoto, Tatsuro; Maehara, Yoshihiko; Yatabe, Yasushi; Mitsudomi, Tetsuya

    2012-01-01

    Many elderly patients suffer from lung cancers, but it is not clear if their lung cancers differ from those of younger patients. In this study, we compared genetic and prognostic characteristics of lung cancers of patients aged ≥75 years with those of patients aged ≤ 64 years. In the genetic analysis, we explored 292 surgically treated non-squamous cell lung cancers with known mutational status of epidermal growth factor (EGFR) and anaplastic lymphoma kinase (ALK). In the prognostic analysis, we retrospectively analyzed 405 surgically treated non-small cell lung cancers (NSCLCs) before the era of routine clinical application of post-surgical adjuvant chemotherapy. Postsurgical recurrence-free survival (RFS) was compared between elderly patients and younger counterparts. The genetic analysis showed elderly non-squamous cell lung cancer patients to have higher prevalence of EGFR mutations (53.1 % vs 42.0%, P = 0.15) and lower prevalence of the ALK translocation (0 % vs 4.5%, P = 0.23) than their younger counterparts. The prognostic analysis showed postsurgical RFS was similar between the elderly NSCLC patients and the younger patients. However in multivariate analysis, adjusting for gender, smoking status, pathological stage, and histology, elderly patients had significantly worse prognoses (HR 1.57, 95% CI, 1.08–2.29; P = 0.02) compared with younger patients. These results suggest differences in genetic and prognostic aspects between elderly lung cancer patients and younger lung cancer patients. PMID:23251849

  11. The root endophyte fungus Piriformospora indica leads to early flowering, higher biomass and altered secondary metabolites of the medicinal plant, Coleus forskohlii

    PubMed Central

    Das, Aparajita; Kamal, Shwet; Shakil, Najam Akhtar; Sherameti, Irena; Oelmüller, Ralf; Dua, Meenakshi; Tuteja, Narendra; Johri, Atul Kumar; Varma, Ajit

    2012-01-01

    This study was undertaken to investigate the influence of plant probiotic fungus Piriformospora indica on the medicinal plant C. forskohlii. Interaction of the C. forskohlii with the root endophyte P. indica under field conditions, results in an overall increase in aerial biomass, chlorophyll contents and phosphorus acquisition. The fungus also promoted inflorescence development, consequently the amount of p-cymene in the inflorescence increased. Growth of the root thickness was reduced in P. indica treated plants as they became fibrous, but developed more lateral roots. Because of the smaller root biomass, the content of forskolin was decreased. The symbiotic interaction of C. forskohlii with P. indica under field conditions promoted biomass production of the aerial parts of the plant including flower development. The plant aerial parts are important source of metabolites for medicinal application. Therefore we suggest that the use of the root endophyte fungus P. indica in sustainable agriculture will enhance the medicinally important chemical production. PMID:22301976

  12. Rice (Oryza sativa L.) containing the bar gene is compositionally equivalent to the nontransgenic counterpart.

    PubMed

    Oberdoerfer, Regina B; Shillito, Raymond D; de Beuckeleer, Marc; Mitten, Donna H

    2005-03-01

    This publication presents an approach to assessing compositional equivalence between grain derived from glufosinate-tolerant rice grain, genetic event LLRICE62, and its nontransgenic counterpart. Rice was grown in the same manner as is common for commercial production, using either conventional weed control practices or glufosinate-ammonium herbicide. A two-season multisite trial design provided a robust data set to evaluate environmental effects between the sites. Statistical comparisons to test for equivalence were made between glufosinate-tolerant rice and a conventional counterpart variety. The key nutrients, carbohydrates, protein, iron, calcium, thiamin, riboflavin, and niacin, for which rice can be the principal dietary source, were investigated. The data demonstrate that rice containing the genetic locus LLRICE62 has the same nutritional value as its nontransgenic counterpart, and most results for nutritional components fall within the range of values reported for rice commodities in commerce. PMID:15740024

  13. Determining the robust counterpart of uncertain spatial optimization model for water supply allocation problem

    NASA Astrophysics Data System (ADS)

    Chaerani, D.; Ruchjana, B. N.; Dewanto, S. P.; Abdullah, A. S.; Rejito, J.; Rosandi, Y.; Dharmawan, I. A.

    2016-02-01

    In this paper we discuss how to get the robust counterpart for the spatial optimization model for water supply allocation (SOMWSA) problem that is proposed by [6]. We employ the robust counterpart methodology that is proposed by Ben-Tal and Nemirovskii [2] also use the new paradigm of robust counterpart methodology of den Hertog et al. [4]. To this end, first we define the uncertain family class of SOMWSA and derive the robust version of the uncertain problem. We assume that there are two uncertain data in SOMWSA problem, ie., the total population and the water demand in a region i at time t. Since the tractability of the problem is very important in Robust Optimization, we discuss three types of uncertainty set, i.e., box, ellipsoidal and polyhedral uncertainty set.

  14. Higher Education and International Capacity Building: Twenty Five Years of Higher Education Links

    ERIC Educational Resources Information Center

    Stephens, David, Ed.

    2009-01-01

    For the past 25 years UK Higher Education institutions have forged research and teaching partnerships with their counterparts overseas. Many of these links were funded by the British Government and managed by the British Council's Higher Education Links Scheme. This book takes an informed and critical look at issues and trends in global higher…

  15. A possible optical counterpart for the triple pulsar system PSR B1620-26

    NASA Technical Reports Server (NTRS)

    Bailyn, Charles D.; Rubinstein, Eric P.; Girard, Terrence M.; Dinescu, Dana I.; Rasio, Frederic A.; Yanny, Brian

    1994-01-01

    We have searched deep optical images of the globular cluster M4 for a possible optical counterpart for the third body in the PSR B1620-26 system. We identify as a possible optical counterpart a star located within 0.3 sec of the nominal pulsar position with V approximately equal to 20. This magnitude is consistent with a main-sequence cluster member with M approximately equal to 0.45 solar mass. However, this star may be blended with fainter stars, and the probability of a chance superposition is nonnegligible.

  16. Results from GROCSE I: A real-time search for gamma ray burst optical counterparts

    SciTech Connect

    Lee, B.; Akerlof, C.; Ables, E.

    1995-10-27

    The GROCSE I experiment (Gamma-Ray Optical Counterpart Search Experiment) is a rapid slewing wide field of view optical telescope at Lawrence Livermore National Laboratory which responds to triggers from the BATSE GRB data telemetry stream that have been processed and distributed by the BACODINE network. GROCSE 1 has been in continuous automated operation since January 1994. As of October 1995, sky images for 22 GRB triggers have been recorded, in some cases while the burst was still emitting gamma rays. The preliminary analysis of eight of these events are presented here. No optical counterparts have yet been detected. Limits for optical emission are given.

  17. Using Penelope to assess the correctness of NASA Ada software: A demonstration of formal methods as a counterpart to testing

    NASA Technical Reports Server (NTRS)

    Eichenlaub, Carl T.; Harper, C. Douglas; Hird, Geoffrey

    1993-01-01

    Life-critical applications warrant a higher level of software reliability than has yet been achieved. Since it is not certain that traditional methods alone can provide the required ultra reliability, new methods should be examined as supplements or replacements. This paper describes a mathematical counterpart to the traditional process of empirical testing. ORA's Penelope verification system is demonstrated as a tool for evaluating the correctness of Ada software. Grady Booch's Ada calendar utility package, obtained through NASA, was specified in the Larch/Ada language. Formal verification in the Penelope environment established that many of the package's subprograms met their specifications. In other subprograms, failed attempts at verification revealed several errors that had escaped detection by testing.

  18. Germany Provides Higher Education without the Frills

    ERIC Educational Resources Information Center

    Labi, Aisha

    2009-01-01

    In Germany, tuition is low because state governments shoulder a much higher percentage of university budgets than in the United States. As a result, most German universities provide far fewer amenities and services, and require their professors to teach longer hours to larger numbers of students than their American counterparts. Because they are…

  19. Maximizing the probability of detecting an electromagnetic counterpart of gravitational-wave events

    NASA Astrophysics Data System (ADS)

    Coughlin, Michael; Stubbs, Christopher

    2016-07-01

    Compact binary coalescences are a promising source of gravitational waves for second-generation interferometric gravitational-wave detectors such as advanced LIGO and advanced Virgo. These are among the most promising sources for joint detection of electromagnetic (EM) and gravitational-wave (GW) emission. To maximize the science performed with these objects, it is essential to undertake a followup observing strategy that maximizes the likelihood of detecting the EM counterpart. We present a follow-up strategy that maximizes the counterpart detection probability, given a fixed investment of telescope time. We show how the prior assumption on the luminosity function of the electro-magnetic counterpart impacts the optimized followup strategy. Our results suggest that if the goal is to detect an EM counterpart from among a succession of GW triggers, the optimal strategy is to perform long integrations in the highest likelihood regions. For certain assumptions about source luminosity and mass distributions, we find that an optimal time investment that is proportional to the 2/3 power of the surface density of the GW location probability on the sky. In the future, this analysis framework will benefit significantly from the 3-dimensional localization probability.

  20. A Counterpart of the Wadati-Konno-Ichikawa Soliton Hierarchy Associated with so(3,R)

    NASA Astrophysics Data System (ADS)

    Ma, Wen-Xiu; Manukure, Solomon; Zheng, Hong-Chan

    2014-09-01

    A counterpart of the Wadati-Konno-Ichikawa (WKI) soliton hierarchy, associated with so(3;R), is presented through the zero curvature formulation. Its spectral matrix is defined by the same linear combination of basis vectors as the WKI one, and its Hamiltonian structures yielding Liouville integrability are furnished by the trace identity

  1. The Optical Counterpart to Gamma-Ray Burst GRB 970228 Observed Using the Hubble Space Telescope

    NASA Technical Reports Server (NTRS)

    Sahu, K. C.; Livio, M.; Petro, L.; Macchetto, F. D.; vanParadijs, J.; Kouveliotou, C.; Fishman, G. J.; Meegan, C. A.; Groot, P. J.; Galama, T.

    1997-01-01

    Although more than 2,000 astronomical gamma-ray bursts (GRBS) have been detected, and numerous models proposed to explain their occurrence, they have remained enigmatic owing to the lack of an obvious counterpart at other wavelengths. The recent ground-based detection of a transient optical source in the vicinity of GRB970228 may therefore have provided a breakthrough. The optical counterpart appears to be embedded in an extended source which, if a galaxy, as has been suggested would lend weight to those models that place GRBs at cosmological distances. Here we report, observations using the Hubble Space Telescope of the transient counterpart and extended source 26 and 39 days after the initial gamma-ray outburst. We find that the counterpart has faded since the initial detection (and continues to fade), but the extended source exhibits no significant change in brightness between the two dates of the observations reported here. The size and apparent constancy of the extended source imply that it is extragalactic, but its faintness makes a definitive statement about its nature difficult. Nevertheless, the decay profile of the transient source is consistent with a popular impulsive-fireball model13, which assumes a merger between two neutron stars in a distant galaxy.

  2. Variable optical/infrared counterpart to the transient gamma-ray source J0109+6134

    NASA Astrophysics Data System (ADS)

    Fernández-Valenzuela, E.; Martí, J.; Luque-Escamilla, P. L.; Muñoz-Arjonilla, A. J.; Paredes, J. M.

    2014-01-01

    Context. We investigate the optical/infrared counterpart to the flaring gamma-ray source J0109+6134, which is believed to be a blazar seen through the Galactic plane. Aims: The original aim of this work was to confirm the previously proposed optical counterpart by means of studying its temporal behaviour. The study was later extended to infrared wavelengths as new data became available. Methods: We conducted a long-term differential CCD photometry campaign using the robotic Liverpool telescope. In addition, we used infrared satellite observations to also explore the source variability at these longer wavelengths. Results: Evidence of variability well correlated with gamma-ray flares has been observed so far only in the infrared domain. This fact strongly supports that the proposed optical/infrared counterpart identification is correct. Moreover, our optical photometric campaign revealed an intense optical flare with 1.7 mag amplitude that occurs on time-scales of weeks. This optical event was observed to evolve without a counterpart in the nearly simultaneous gamma-ray monitoring by the Fermi satellite. Gamma-ray orphan optical flares have rarely been observed in other blazars, and J0109+6134 appears to be an interesting additional example for future studies.

  3. EVN detection of a compact radio source as a counterpart to Fermi J1418+3541

    NASA Astrophysics Data System (ADS)

    Frey, Sandor; Paragi, Zsolt; Gabanyi, Krisztina; An, Tao

    2013-01-01

    Fermi J1418+3541 is a suspected blazar recently detected as a flaring gamma-ray point source, identified with likely radio, optical and infrared counterparts within the Fermi LAT error circle (Dutka et al. 2012, ATEL #4643; Mahabal et al. 2012, ATEL #4645; Bernieri et al. 2013, A&A, in press, arXiv:1212.6868).

  4. Methylotrophic bacteria symbiosis with the higher plants as means of minimization of the lower hydrocarbons concentration during artificial ecosystem gas exchange

    NASA Astrophysics Data System (ADS)

    Berkovich, Yuliy; Smolyanina, Svetlana; Moukhamedieva, Lana; Mardanov, Robert; Doronina, Nina; Ivanova, Ekaterina

    Plant growth unit should be included in the LSS for the space vehicles for vitamin greens supply and psychological support of cosmonauts during long-term missions. The lower hydrocarbons such as methane, methanol, methylated sulfuric compounds and methylated amines, ethylene and so on, are the natural products of human and plant metabolism and usually considered as the air pollutions. It is shown, that one way to decrease the lower hydrocarbons concentration in the artificial ecosystems could be colonization of the plants by methylotrophic bacteria. The aerobic methylotrophic bacteria possess unique ability to use methane and its oxidized or replaced derivatives without food damage and human, animals or plants infection. We have found that methylotrophic bacteria are the phyto-symbiotic bacteria: they stimulate growth and development of the colonized plants because of synthesizing cytokinins and auxins, and vitamin B12.Two collection strains of the obligate methylotrophic bacteria - Methylovorus mays C and Methylomonas metanica S - were chosen because of their high activity to assimilate the lower hydrocarbons due to functioning of methanoldehydrogenase, methanmonooxigenase and ribulose monophosphate cycle enzymes system.Colonization of the leaf cabbage Brassica chinensis L. by these strains led to approximately 30 % reduce of methanol and methane concentration in the air inside phytotron. Experimental estimations of the influence of methylotrophic bacteria on leafy greens growth and development are obtained.

  5. Common sequence motifs coding for higher-plant and prokaryotic O-acetylserine (thiol)-lyases: bacterial origin of a chloroplast transit peptide?

    PubMed

    Rolland, N; Job, D; Douce, R

    1993-08-01

    A comparison of the amino acid sequence of O-acetylserine (thiol)-lyase (EC 4.2.99.8) from Escherichia coli and the isoforms of this enzyme found in the cytosolic and chloroplastic compartments of spinach (Spinacia oleracea) leaf cells allows the essential lysine residue involved in the binding of the pyridoxal 5'-phosphate cofactor to be identified. The results of further sequence comparison of cDNAs coding for these proteins are discussed in the frame of the endosymbiotic theory of chloroplast evolution. The results are compatible with a mechanism in which the chloroplast enzyme originated from the cytosolic enzyme and both plant genes originated from a common prokaryotic ancestor. The comparison also suggests that the 5'-non-coding sequence of the bacterial gene was transferred to the plant cell nucleus and that it has been used to create the N-terminal portions of both plant enzymes, and possibly the transit peptide of the chloroplast enzyme. PMID:7916619

  6. Use of human wastes oxidized to different degrees in cultivation of higher plants on the soil-like substrate intended for closed ecosystems

    NASA Astrophysics Data System (ADS)

    Tikhomirov, A. A.; Kudenko, Yu. A.; Ushakova, S. A.; Tirranen, L. S.; Gribovskaya, I. A.; Gros, J.-B.; Lasseur, Ch.

    2010-09-01

    To close mass exchange loops in bioregenerative life support systems more efficiently, researchers of the Institute of Biophysics SB RAS (Krasnoyarsk, Russia) have developed a procedure of wet combustion of human wastes and inedible parts of plants using H 2O 2 in alternating electromagnetic field. Human wastes pretreated in this way can be used as nutrient solutions to grow plants in the phototrophic unit of the LSS. The purpose of this study was to explore the possibilities of using human wastes oxidized to different degrees to grow plants cultivated on the soil-like substrate (SLS). The treated human wastes were analyzed to test their sterility. Then we investigated the effects produced by human wastes oxidized to different degrees on growth and development of wheat plants and on the composition of microflora in the SLS. The irrigation solution contained water, substances extracted from the substrate, and certain amounts of the mineralized human wastes. The experiments showed that the human wastes oxidized using reduced amounts of 30% H 2O 2: 1 ml/g of feces and 0.25 ml/ml of urine were still sterile. The experiments with wheat plants grown on the SLS and irrigated by the solution containing treated human wastes in the amount simulating 1/6 of the daily diet of a human showed that the degree of oxidation of human wastes did not significantly affect plant productivity. On the other hand, the composition of the microbiota of irrigation solutions was affected by the oxidation level of the added metabolites. In the solutions supplemented with partially oxidized metabolites yeast-like microscopic fungi were 20 times more abundant than in the solutions containing fully oxidized metabolites. Moreover, in the solutions containing incompletely oxidized human wastes the amounts of phytopathogenic bacteria and denitrifying microorganisms were larger. Thus, insufficiently oxidized sterile human wastes added to the irrigation solutions significantly affect the composition of

  7. Initial Optical Counterpart Identifications for Chandra Deep Survey X-ray Sources towards the Galactic Center

    NASA Astrophysics Data System (ADS)

    Zhao, P.; Grindlay, J. E.; Hong, J.; Laycock, S.; Baganoff, F. K.; Muno, M. P.; Garmire, G. P.; Morris, M.

    2003-03-01

    We present the initial optical counterpart identifications for the Chandra Catalog of X-ray sources towards the Galactic Center (Muno et al. ApJ submitted). 2357 X-ray point sources are detected during 590 ks of Chandra ACIS-I observations with a 17'x17' field around SgrA*. The search for their optical counterparts is conducted with moderately deep V, R, I and Hα images covering the same field taken with the Mosaic camera on the CTIO 4-m telescope in March 2000 as part of the Chandra Multiwavelength Plane (ChaMPlane) Survey. The error radius of each Chandra source is estimated with a raytrace/wavdetect simulation based on the source off-axis angle and net counts. Some 237 sources are detected below 1.2 keV and with >99% source significance in the full 17' field. They are likely sources in the foreground of the Galactic Center. 204 of the 237 sources have matching optical counterparts. For the ˜2000 sources detected in the hard band (2.5--8 keV), only ˜10% have optical matching (at R<23). And most of these ˜10% matches are likely coincident matches with foreground stars. We present our optical counterpart identification method used for the ChaMPlane Survey and the V, R, I, Hα magnitudes of the optical counterparts of this initial sample. This work is supported by NASA/SAO grant AR1-2001X, AR2-3002A and NSF grant AST-0098683.

  8. The size of the light-harvesting antenna of higher plant photosystem II is regulated by illumination intensity through transcription of antenna protein genes.

    PubMed

    Borisova-Mubarakshina, M M; Vetoshkina, D V; Rudenko, N N; Shirshikova, G N; Fedorchuk, T P; Naydov, I A; Ivanov, B N

    2014-06-01

    In arabidopsis plants, with an increase in illumination intensity during growth the extent of reduction of the plastoquinone pool in the photosynthetic electron transport chain increased, whereas the effective quantum yield of photosynthesis decreased. After 5 days of growth under high illumination intensity, these parameters in high light returned to values observed in "shade-adapted" plants in low light. During the same period, the size of the antenna decreased, correlating with a decrease in the amounts of proteins of peripheral pigment-protein complexes. It was found that the decrease in the amounts of these proteins occurred due to suppression of transcription of their genes. PMID:25100009

  9. An Essential Component in Chloroplast Development and Maintenance at Moderate High Temperature in Higher Plants: Chloroplast-targeted FtsH11 Proteases

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Among the 12 predicted FtsH proteases in Arabidopsis, AtFtsH11 is the only metalloprotease targeting to both chloroplast and mitochondria and the only one essential for Arabidopsis plant to survive at moderate heat stress at all developmental stages. Under optimal conditions, atftsh11 mutants were...

  10. Higher Skills. A Case Study of the Role of Further Education Colleges in Meeting the Training Needs of the Small Plant and Tool Hire Industry.

    ERIC Educational Resources Information Center

    Further Education Unit, London (England).

    A British project explored ways further education colleges could help meet training needs of small businesses, specifically the small plant and tool hire industry. The industry's leading organization, the Hire Association of Europe (HAE), provided a list of members; responsibility for making contact rested with the colleges. The most effective…

  11. Identifying Elusive Electromagnetic Counterparts to Gravitational Wave Mergers: An End-to-end Simulation

    NASA Astrophysics Data System (ADS)

    Nissanke, Samaya; Kasliwal, Mansi; Georgieva, Alexandra

    2013-04-01

    Combined gravitational wave (GW) and electromagnetic (EM) observations of compact binary mergers should enable detailed studies of astrophysical processes in the strong-field gravity regime. This decade, ground-based GW interferometers promise to routinely detect compact binary mergers. Unfortunately, networks of GW interferometers have poor angular resolution on the sky and their EM signatures are predicted to be faint. Therefore, a challenging goal will be to unambiguously pinpoint the EM counterparts of GW mergers. We perform the first comprehensive end-to-end simulation that focuses on: (1) GW sky localization, distance measures, and volume errors with two compact binary populations and four different GW networks; (2) subsequent EM detectability by a slew of multiwavelength telescopes; and (3) final identification of the merger counterpart amidst a sea of possible astrophysical false positives. First, we find that double neutron star binary mergers can be detected out to a maximum distance of 400 Mpc (or 750 Mpc) by three (or five) detector GW networks, respectively. Neutron-star-black-hole binary mergers can be detected a factor of 1.5 further out; their median to maximum sky localizations are 50-170 deg2 (or 6-65 deg2) for a three (or five) detector GW network. Second, by optimizing depth, cadence, and sky area, we quantify relative fractions of optical counterparts that are detectable by a suite of different aperture-size telescopes across the globe. Third, we present five case studies to illustrate the diversity of scenarios in secure identification of the EM counterpart. We discuss the case of a typical binary, neither beamed nor nearby, and the challenges associated with identifying an EM counterpart at both low and high Galactic latitudes. For the first time, we demonstrate how construction of low-latency GW volumes in conjunction with local universe galaxy catalogs can help solve the problem of false positives. We conclude with strategies that would

  12. The host galaxy and Fermi-LAT counterpart of HESS J1943+213

    NASA Astrophysics Data System (ADS)

    Peter, D.; Domainko, W.; Sanchez, D. A.; van der Wel, A.; Gässler, W.

    2014-11-01

    Context. The very-high energy (VHE, E> 100 GeV) gamma-ray sky shows diverse Galactic and extragalactic source populations. For some sources the astrophysical object class could not be identified so far. Aims: The nature (Galactic or extragalactic) of the VHE gamma-ray source HESS J1943+213 is explored. We specifically investigate the proposed near-infrared counterpart 2MASS J19435624+2118233 of HESS J1943+213 and investigate the implications of a physical association. Methods: We present K-band imaging from the 3.5 m CAHA telescope of 2MASS J19435624+2118233. Furthermore, 5 years of Fermi-LAT data were analyzed to search for a high-energy (HE, 100 MeV counterpart. Results: The CAHA observations revealed that the near-infrared counterpart is extended with an intrinsic half light radius of 2''-2.5''. These observations also show a smooth, centrally concentrated light profile that is typical of a galaxy, and thus point toward an extragalactic scenario for the VHE gamma-ray source, assuming that the near-infrared source is the counterpart of HESS J1943+213. A high-Sérsic index profile provides a better fit than an exponential profile, indicating that the surface brightness profile of 2MASS J19435624+2118233 follows that of a typical, massive elliptical galaxy more closely than that of a disk galaxy. With Fermi-LAT a HE counterpart is found with a power-law spectrum above 1 GeV, with a normalization of (3.0 ± 0.8stat ± 0.6sys) × 10-15 cm-2 s-1 MeV-1 at the decorrelation energy Edec = 15.1 GeV and a spectral index of Γ = 1.59 ± 0.19stat ± 0.13sys. This gamma-ray spectrum shows a rather sharp break between the HE and VHE regimes of ΔΓ = 1.47 ± 0.36. Conclusions: The infrared and HE data strongly favor an extragalactic origin of HESS J1943+213, where the infrared counterpart traces the host galaxy of an extreme blazar and where the rather sharp spectral break between the HE and VHE regime indicates attenuation on extragalactic background light. The

  13. The StEllar Counterparts of COmpact high velocity clouds (SECCO) survey. I. Photos of ghosts

    NASA Astrophysics Data System (ADS)

    Bellazzini, M.; Beccari, G.; Battaglia, G.; Martin, N.; Testa, V.; Ibata, R.; Correnti, M.; Cusano, F.; Sani, E.

    2015-03-01

    We present an imaging survey that searches for the stellar counterparts of recently discovered ultra-compact high-velocity H i clouds (UCHVC). It has been proposed that these clouds are candidate mini-haloes in the Local Group and its surroundings within a distance range of 0.25-2.0 Mpc. Using the Large Binocular Telescope we obtained wide-field (≃ 23' × 23') g- and r-band images of the twenty-five most promising and most compact clouds amongst the fifty-nine that have been identified. Careful visual inspection of all the images does not reveal any stellar counterpart that even slightly resembles Leo P, the only local dwarf galaxy that was found as a counterpart to a previously detected high-velocity cloud. Only a possible distant (D> 3.0 Mpc) counterpart to HVC274.68+74.70-123 has been identified in our images. The point source photometry in the central 17.3' × 7.7' chips reaches r ≤ 26.5 and is expected to contain most of the stellar counterparts to the UCHVCs. However, no obvious stellar over-density is detected in any of our fields, in marked contrast to our comparison Leo P field, in which the dwarf galaxy is detected at a >30σ-significance level. Only HVC352.45+59.06+263 may be associated with a weak over-density, whose nature cannot be ascertained with our data. Sensitivity tests show that our survey would have detected any dwarf galaxy dominated by an old stellar population, with an integrated absolute magnitude of MV ≤ - 8.0 and a half-light radius of rh ≤ 300 pc that lies within 1.5 Mpc of us, thereby confirming that it is unlikely that the observed UCHVCs are associated with the stellar counterparts typical of known Local Group dwarf galaxies. Based on data acquired using the Large Binocular Telescope (LBT). The LBT is an international collaboration amongst institutions in the United States, Italy, and Germany. LBT Corporation partners are The University of Arizona on behalf of the Arizona university system; Istituto Nazionale di Astrofisica

  14. IDENTIFYING ELUSIVE ELECTROMAGNETIC COUNTERPARTS TO GRAVITATIONAL WAVE MERGERS: AN END-TO-END SIMULATION

    SciTech Connect

    Nissanke, Samaya; Georgieva, Alexandra; Kasliwal, Mansi

    2013-04-20

    Combined gravitational wave (GW) and electromagnetic (EM) observations of compact binary mergers should enable detailed studies of astrophysical processes in the strong-field gravity regime. This decade, ground-based GW interferometers promise to routinely detect compact binary mergers. Unfortunately, networks of GW interferometers have poor angular resolution on the sky and their EM signatures are predicted to be faint. Therefore, a challenging goal will be to unambiguously pinpoint the EM counterparts of GW mergers. We perform the first comprehensive end-to-end simulation that focuses on: (1) GW sky localization, distance measures, and volume errors with two compact binary populations and four different GW networks; (2) subsequent EM detectability by a slew of multiwavelength telescopes; and (3) final identification of the merger counterpart amidst a sea of possible astrophysical false positives. First, we find that double neutron star binary mergers can be detected out to a maximum distance of 400 Mpc (or 750 Mpc) by three (or five) detector GW networks, respectively. Neutron-star-black-hole binary mergers can be detected a factor of 1.5 further out; their median to maximum sky localizations are 50-170 deg{sup 2} (or 6-65 deg{sup 2}) for a three (or five) detector GW network. Second, by optimizing depth, cadence, and sky area, we quantify relative fractions of optical counterparts that are detectable by a suite of different aperture-size telescopes across the globe. Third, we present five case studies to illustrate the diversity of scenarios in secure identification of the EM counterpart. We discuss the case of a typical binary, neither beamed nor nearby, and the challenges associated with identifying an EM counterpart at both low and high Galactic latitudes. For the first time, we demonstrate how construction of low-latency GW volumes in conjunction with local universe galaxy catalogs can help solve the problem of false positives. We conclude with strategies

  15. Collection and conversion of silicon furnace waste gas into higher value products: Phase 3, 6 MW pilot plant dc closed furnace technology. Final report

    SciTech Connect

    Dosaj, V.D.

    1995-01-01

    The construction and operation of a 6 MW, closed dc furnace for smelting silicon was the primary focus of Phase 3. A 6 MW, dc closed furnace pilot plant was built in East Selkirk, Manitoba, Canada. The furnace is equipped with world`s most modern automatic control system used to control and monitor the process variables and operational data. This control system is suitable for commercial applications and could be used with either closed or open dc furnaces for smelting silicon or ferrosilicon. The construction was started in September 1990, and the facility was operational within 18 months. Following successful commissioning of the pilot plant in June 1992, twelve smelting test campaigns were conducted through November 1994.

  16. Preparation protocols for high-activity photosystem II membrane particles of green algae and higher plants, pH dependence of oxygen evolution and comparison of the S2-state multiline signal by X-band EPR spectroscopy.

    PubMed

    Schiller, H; Dau, H

    2000-01-01

    Photosystem II (PS II) membrane particles are particularly well suited for various types of spectroscopic investigations on the PS II manganese complex. Here we present: (1) a preparation protocol for PS II membrane particles of higher plants, which yields exceptionally high oxygen-evolution activity due to the use of glycinebetaine as a PS II-stabilizing agent; (2) preparation protocols for highly active PS II membrane particles for the green algae Scenedesmus obliquus and Chlamydomonas reinhardtii; (3) a determination of pH dependence of oxygen evolution for spinach and Scenedesmus; (4) a comparison of the EPR multiline signal observed in the S2-state of green algae and higher plants of PS II membrane particles. A clearly broader type of multiline EPR signal is observed in green algae. PMID:10942078

  17. Complexation and Toxicity of Copper in Higher Plants. I. Characterization of Copper Accumulation, Speciation, and Toxicity in Crassula helmsii as a New Copper Accumulator1[W][OA

    PubMed Central

    Küpper, Hendrik; Götz, Birgit; Mijovilovich, Ana; Küpper, Frithjof C.; Meyer-Klaucke, Wolfram

    2009-01-01

    The amphibious water plant Crassula helmsii is an invasive copper (Cu)-tolerant neophyte in Europe. It now turned out to accumulate Cu up to more than 9,000 ppm in its shoots at 10 μm (=0.6 ppm) Cu2+ in the nutrient solution, indicating that it is a Cu hyperaccumulator. We investigated uptake, binding environment, and toxicity of Cu in this plant under emerged and submerged conditions. Extended x-ray absorption fine structure measurements on frozen-hydrated samples revealed that Cu was bound almost exclusively by oxygen ligands, likely organic acids, and not any sulfur ligands. Despite significant differences in photosynthesis biochemistry and biophysics between emerged and submerged plants, no differences in Cu ligands were found. While measurements of tissue pH confirmed the diurnal acid cycle typical for Crassulacean acid metabolism, Δ13C measurements showed values typical for regular C3 photosynthesis. Cu-induced inhibition of photosynthesis mainly affected the photosystem II (PSII) reaction center, but with some unusual features. Most obviously, the degree of light saturation of electron transport increased during Cu stress, while maximal dark-adapted PSII quantum yield did not change and light-adapted quantum yield of PSII photochemistry decreased particularly in the first 50 s after onset of actinic irradiance. This combination of changes, which were strongest in submerged cultures, shows a decreasing number of functional reaction centers relative to the antenna in a system with high antenna connectivity. Nonphotochemical quenching, in contrast, was modified by Cu mainly in emerged cultures. Pigment concentrations in stressed plants strongly decreased, but no changes in their ratios occurred, indicating that cells either survived intact or died and bleached quickly. PMID:19641032

  18. Molecular characterization of a novel heavy metal uptake transporter from higher plants and its potential for use in phytoremediation. 1998 annual progress report

    SciTech Connect

    Schroeder, J.I.

    1998-06-01

    'Soils and waters contaminated with high levels of heavy metals such as Cadmium, Lead and Copper are detrimental to human and environmental health. Many human disorders have been attributed to environmental contamination by heavy metals. Removal of heavy metals from highly contaminated sites is therefore a very costly but necessary process that is currently being pursued. Recent research in several laboratories indicates that uptake of heavy metals into plants via the root system may provide a cost-effective approach for decontamination of certain heavy metal-laden soils and waters. Several mechanisms have been identified, which allow detoxification in the cytosol and vacuoles of plants. However, the molecular biological mechanisms by which heavy metals are transported from soils across the plasma membrane into roots have remained largely unknown. In recent research, the laboratory has cloned a cation uptake transporter cDNA from plants. Yeast cells expressing this cDNA show enhanced uptake of calcium and cadmium. The proposed research is testing the transport of toxic and nutrient metals by the encoded protein.'

  19. A search for optical counterparts of nine galactic X-ray sources

    NASA Technical Reports Server (NTRS)

    Davidsen, A.; Malina, R.; Bowyer, S.

    1976-01-01

    Results of a photographic and spectrophotometric search to a limiting B magnitude of approximately 18.5 for the optical counterparts of nine galactic X-ray sources with good positions are reported. The sources included in this survey are 3U 1709-23, 1728-16, 1728-24, 1758-20, 1758-25, 1811-17, 1813-14, 1837+04, 1908+00. Optical candidates for six of these sources are discussed, including blue objects which may be the optical counterparts of 1709-23 and 1728-16, a distant B star near 1908+00, and a very unusual strong-emission-line object which is probably associated with 1728-24 (GX 2+5). Coordinates, magnitudes, colors, spectral data, and finding charts are presented.

  20. Potential Optical Counterparts to High Mass X-Ray and γ-Ray Binaries

    NASA Astrophysics Data System (ADS)

    Mitchell, Carl; McSwain, M. V.

    2011-01-01

    We seek to identify optical counterparts to several previously discovered high mass X-ray binaries and γ-ray sources from the Liu et al. and Fermi first year catalogues. Observations were taken with the CTIO 0.9-meter telescope, operated by the SMARTS Consortium. Photometric data were taken in the Strömgren b and y filters, as well as a narrow-band Hα filter. We present color-color diagrams of y-Hα vs. b-y for each field, and candidates for optical counterparts were selected based on their excesses of Hα emission. We also present spectral energy distributions for select candidates. This work is supported by the NSF REU site grant PHY-0849416, NASA DPR No. NNX09AT67G, and Lehigh University. We also thank the SMARTS Consortium, Rachael Roettenbacher, Tina Aragona, and Amber Marsh.

  1. The X-Ray Counterpart to LAT PSR J2021+4026 and Its Interesting Spectrum

    NASA Technical Reports Server (NTRS)

    Weisskopf, Martin C.; Becker, W.; Carraminana, A.; De Luca, A.; Dormandy, M.; Harding, A.; Kanbach, G.; O'Dell, S. L.; Parkinson, P. Saz; Ray, P.; Razzano, M.; Romani, R.; Tennant, A. F.; Swarz, D. A.; Thompson, D.; Ziegler, M.

    2011-01-01

    We report on the likely identification of the X-ray counterpart to LAT PSR J2021+4026, using the Chandra X-Ray Observatory ACIS-S3 and timing analysis of Large Area telescope (LAT) data from the Fermi satellite. The X-ray source that lies closest (10 arcsec) to the position determined from the Fermi-LAT timing solution has no cataloged infrared-to-visible counterpart and we have set an upper limit to its optical I and R band emission. The source exhibits a X-ray spectrum which is different when compared to Geminga and CTA 1, and this may have implications for the evolutionary track of radio-quiet gamma-ray pulsars.

  2. The prokaryotic zinc-finger: structure, function and comparison with the eukaryotic counterpart.

    PubMed

    Malgieri, Gaetano; Palmieri, Maddalena; Russo, Luigi; Fattorusso, Roberto; Pedone, Paolo V; Isernia, Carla

    2015-12-01

    Classical zinc finger (ZF) domains were thought to be confined to the eukaryotic kingdom until the transcriptional regulator Ros protein was identified in Agrobacterium tumefaciens. The Ros Cys2 His2 ZF binds DNA in a peculiar mode and folds in a domain significantly larger than its eukaryotic counterpart consisting of 58 amino acids (the 9-66 region) arranged in a βββαα topology, and stabilized by a conserved, extensive, 15-residue hydrophobic core. The prokaryotic ZF domain, then, shows some intriguing new features that make it interestingly different from its eukaryotic counterpart. This review will focus on the prokaryotic ZFs, summarizing and discussing differences and analogies with the eukaryotic domains and providing important insights into their structure/function relationships. PMID:26365095

  3. A Faint Near-Infrared Counterpart to the AXP 1E 2259+58.6

    NASA Technical Reports Server (NTRS)

    Hulleman, F.; Tennant, Allyn F., Jr.; vanKerkwijk, M. H.; Kulkarni, S. R.; Kouveliotou, C.; Patel, S. K.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    We present near-infrared and optical observations of the field of the Anomalous X-ray Pulsar 1E 2259+58.6 taken with the Keck telescope. We derive a subarcsecond Chandra position and tie it to our optical reference frame using other stars in the field. We find a very faint source, K(s) = 21.7 +/- 0.2 mag, with a position coincident with the Chandra position. We argue that this is the counterpart. In the J, I, and R bands, we derive (two sigma) limits of 23.8, 25.6 and 26.4mag, respectively. As with 4U 0142+61, for which a similarly faint counterpart was found, our results are inconsistent with models in which the source is powered by accretion from a disk. The only model that is not inconsistent, appears to be that in which 1E 2259+58.6 is a magnetar.

  4. Optical counterparts of two ULXs in NGC 5474 and NGC 3627 (M 66)

    NASA Astrophysics Data System (ADS)

    Avdan, S.; Vinokurov, A.; Fabrika, S.; Atapin, K.; Avdan, H.; Akyuz, A.; Sholukhova, O.; Aksaker, N.; Valeev, A.

    2016-01-01

    We identified two optical counterparts of brightest ultraluminous X-ray sources (ULXs) in galaxies NGC 5474 and NGC 3627 (M66). The counterparts in Hubble Space Telescope images are very faint, their V magnitudes are 24.7 (MV ≈ -4.5) and 25.9 (MV ≈ -4.2), respectively. NGC 5474 X-1 changes the X-ray flux more than two orders of magnitude, in its bright state it has LX ≈ 1.6 × 1040 erg s-1, the spectrum is best fitted by an absorbed power law model with a photon index Γ ≈ 0.94. M66 X-1 varies in X-rays with a factor of ˜2.5, its maximal luminosity being 2.0 × 1040 erg s-1 with Γ ≈ 1.7. Optical spectroscopy of the NGC 5474 X-1 has shown a blue spectrum, which however was contaminated by a nearby star of 23 mag, but the counterpart has a redder spectrum. Among other objects captured by the slit are a background emission-line galaxy (z = 0.359) and a new young cluster of NGC 5474. We find that these two ULXs have largest X-ray-to-optical ratios of LX/Lopt ˜ 7000 for NGC 5474 X-1 (in its bright state) and 8000 for M66 X-1 both with the faintest optical counterparts ever measured. Probably their optical emission originates from the donor star. If they have super-Eddington accretion discs with stellar-mass black holes, they may also have the lowest mass accretion rates among ULXs such as in M81 X-6 and NGC 1313 X-1.

  5. A possible WISE counterpart of the New Optical Transient SSS130101:122222-311525

    NASA Astrophysics Data System (ADS)

    Li, K. L.; Kong, A. K. H.

    2013-01-01

    Following the CRTS detection of a new optical transient near the Galactic plane (b~30 deg), SSS130101:122222 (ATel #4699), we searched in the Wide-field Infrared Survey Explorer (WISE; Wright et al. 2010 AJ, 140, 1868) catalog and found a possible WISE pre-burst counterpart, WISE J122221.66-311524.6, with an offset of 0.5 arcsec.

  6. VizieR Online Data Catalog: Herschel far-IR counterparts of SDSS galaxies (Dominguez+, 2014)

    NASA Astrophysics Data System (ADS)

    Dominguez Sanchez, H.; Bongiovanni, A.; Lara-Lopez, M. A.; Oteo, I.; Cepa, J.; Perez Garcia, A. M.; Sanchez-Portal, M.; Ederoclite, A.; Lutz, D.; Cresci, G.; Delvecchio, I.; Berta, S.; Magnelli, B.; Popesso, P.; Pozzi, F.; Riguccini, L.

    2015-01-01

    In this paper, we present results for galaxies from the SDSS-DR7, with a counterpart from the PEP (Lutz et al., 2011, Cat. J/A+A/532/A90) Herschel survey in two different fields: the COSMOS field (Scoville et al. 2007ApJS..172....1S) and the Lockman Hole (LH hereafter; Lockman, Jahoda & McCammon 1986ApJ...302..432L). (1 data file).

  7. XTE J1752-223: Optical spectroscopy and infrared counterpart detection

    NASA Astrophysics Data System (ADS)

    Torres, M. A. P.; Steeghs, D.; Jonker, P. G.; Thompson, I.; Soderberg, A. M.

    2009-10-01

    Prompted by the discovery of its bright optical counterpart and the announcement of increased X-ray activity (ATels #2258, #2259, #2261, #2265, #2263), we have acquired additional observations of XTE J1752-223 at optical and near-infrared wavelengths. OPTICAL SPECTROSCOPY: An optical spectrum covering 3330-9165 Angstrom was obtained with the MIKE echelle spectrograph on the Magellan Clay telescope starting on 2009 Oct 26 UT 23:52.

  8. A search for the radio counterpart to the 1994 March 1 gamma-ray burst

    NASA Technical Reports Server (NTRS)

    Frail, D. A.; Kulkarni, S. R.; Hurley, K. C.; Fishman, G. J.; Kouveliotou, C.; Meegan, C. A.; Sommer, M.; Boer, M.; Niel, M.; Cline, T.

    1994-01-01

    We report on the results of a search for the radio counterpart to the bright gamma-ray burst of 1994 March 1. Using the Dominion Radio Astrophysical Observatory Synthesis Telescope sensitive, wide-field radio images at 1.4 GHz and 0.4 GHz were made of a region around GRB 940301. A total of 15 separate radio images were obtained at each frequency, sampling a near-continuous range of post-burst timescales between 3 and 15 days, as well as 26, 47, and 99 days. We place an upper limit of 3.5 mJy on a fading/flaring radio counterpart at 1.4 GHz and 55 mJy at 0.4 GHz. Unlike past efforts our counterpart search maintains high sensitivity over two decades of post-burst time durations. Time-variable radio emission after the initial gamma-ray burst is a prediction of all fireball models, currently the most popular model for gamma-ray bursts. Our observations allow us to put significant constraints on the fireball parameters for cosmological models of gamma-ray bursts.

  9. Plants: Novel Developmental Processes.

    ERIC Educational Resources Information Center

    Goldberg, Robert B.

    1988-01-01

    Describes the diversity of plants. Outlines novel developmental and complex genetic processes that are specific to plants. Identifies approaches that can be used to solve problems in plant biology. Cites the advantages of using higher plants for experimental systems. (RT)

  10. Engineering stategies and implications of using higher plants for throttling gas and water exchange in a controlled ecological life support system

    NASA Technical Reports Server (NTRS)

    Chamberland, Dennis; Wheeler, Raymond M.; Corey, Kenneth A.

    1993-01-01

    Engineering stategies for advanced life support systems to be used on Lunar and Mars bases involve a wide spectrum of approaches. These range from purely physical-chemical life support strategies to purely biological approaches. Within the context of biological based systems, a bioengineered system can be devised that would utilize the metabolic mechanisms of plants to control the rates of CO2 uptake and O2 evolution (photosynthesis) and water production (transpiration). Such a mechanism of external engineering control has become known as throttling. Research conducted at the John F. Kennedy Space Center's Controlled Ecological Life Support System Breadboard Project has demonstrated the potential of throttling these fluxes by changing environmental parameters affecting the plant processes. Among the more effective environmental throttles are: light and CO2 concentration for controllingthe rate of photsynthesis and humidity and CO2 concentration for controlling transpiration. Such a bioengineered strategy implies control mechanisms that in the past have not been widely attributed to life support systems involving biological components and suggests a broad range of applications in advanced life support system design.

  11. Polypeptide composition of bacterial cyclic diguanylic acid-dependent cellulose synthase and the occurrence of immunologically crossreacting proteins in higher plants

    SciTech Connect

    Mayer, R.; Ross, P.; Weinhouse, H.; Amikam, D.; Volman, G.; Ohana, P.; Benziman, M. ); Calhoon, R.D.; Wong, Hing C.; Emerick, A.W. )

    1991-06-15

    To comprehend the catalytic and regulatory mechanism of the cyclic diguanylic acid (c-di-GMP)-dependent cellulose synthase of Acetobacter xylinum and its relatedness to similar enzymes in other organisms, the structure of this enzyme was analyzed at the polypeptide level. The enzyme, purified 350-fold by enzyme-product entrapment, contains three major peptides (90, 67, and 54 kDa), which, based on direct photoaffinity and immunochemical labeling and amino acid sequence analysis, are constituents of the native cellulose synthase. Labeling of purified synthase with either ({sup 32}P)c-di-GMP or ({alpha}-{sup 32}P)UDP-glucose indicates that activator- and substrate-specific binding sites are most closely associated with the 67- and 54-kDa peptides, respectively, whereas marginal photolabeling is detected in the 90-k-Da peptide. However, antibodies raised against a protein derived from the cellulose synthase structural gene (bcsB) specifically label all three peptides. The authors suggest that the structurally related 67- and 54-kDa peptides are fragments proteolytically derived from the 90-kDa peptide encoded by bcsB. The anti-cellulose synthase antibodies crossreact with a similar set of peptides derived from other cellulose-producing microorganisms and plants such as Agrobacterium tumefaciens, Rhizobium leguminosarum, mung bean, peas, barley, and cotton. The occurrence of such cellulose synthase-like structures in plant species suggests that a common enzymatic mechanism for cellulose biogenesis is employed throughout nature.

  12. Evolutionary analyses of the 12-kDa acidic ribosomal P-proteins reveal a distinct protein of higher plant ribosomes

    PubMed Central

    Szick, Kathleen; Springer, Mark; Bailey-Serres, Julia

    1998-01-01

    The P-protein complex of eukaryotic ribosomes forms a lateral stalk structure in the active site of the large ribosomal subunit and is thought to assist in the elongation phase of translation by stimulating GTPase activity of elongation factor-2 and removal of deacylated tRNA. The complex in animals, fungi, and protozoans is composed of the acidic phosphoproteins P0 (35 kDa), P1 (11–12 kDa), and P2 (11–12 kDa). Previously we demonstrated by protein purification and microsequencing that ribosomes of maize (Zea mays L.) contain P0, one type of P1, two types of P2, and a distinct P1/P2 type protein designated P3. Here we implemented distance matrices, maximum parsimony, and neighbor-joining analyses to assess the evolutionary relationships between the 12 kDa P-proteins of maize and representative eukaryotic species. The analyses identify P3, found to date only in mono- and dicotyledonous plants, as an evolutionarily distinct P-protein. Plants possess three distinct groups of 12 kDa P-proteins (P1, P2, and P3), whereas animals, fungi, and protozoans possess only two distinct groups (P1 and P2). These findings demonstrate that the P-protein complex has evolved into a highly divergent complex with respect to protein composition despite its critical position within the active site of the ribosome. PMID:9482893

  13. Higher Education.

    ERIC Educational Resources Information Center

    Hendrickson, Robert M.; Gregory, Dennis E.

    Decisions made by federal and state courts during 1983 concerning higher education are reported in this chapter. Issues of employment and the treatment of students underlay the bulk of the litigation. Specific topics addressed in these and other cases included federal authority to enforce regulations against age discrimination and to revoke an…

  14. Higher Education.

    ERIC Educational Resources Information Center

    Hendrickson, Robert M.

    Litigation in 1987 was very brisk with an increase in the number of higher education cases reviewed. Cases discussed in this chapter are organized under four major topics: (1) intergovernmental relations; (2) employees, involving discrimination claims, tenured and nontenured faculty, collective bargaining and denial of employee benefits; (3)…

  15. Higher Education.

    ERIC Educational Resources Information Center

    Hendrickson, Robert M.; Finnegan, Dorothy E.

    The higher education case law in 1988 is extensive. Cases discussed in this chapter are organized under five major topics: (1) intergovernmental relations; (2) employees, involving discrimination claims, tenured and nontenured faculty, collective bargaining, and denial of employee benefits; (3) students, involving admissions, financial aid, First…

  16. Higher Education.

    ERIC Educational Resources Information Center

    Hendrickson, Robert M.

    This eighth chapter of "The Yearbook of School Law, 1986" summarizes and analyzes over 330 state and federal court cases litigated in 1985 in which institutions of higher education were involved. Among the topics examined were relationships between postsecondary institutions and various governmental agencies; discrimination in the employment of…

  17. ANTARES neutrino detection: kinematic evidence that the Swift/XRT X-ray counterpart is a likely Upper Sco member

    NASA Astrophysics Data System (ADS)

    Mamajek, Eric E.

    2015-10-01

    The star USNO-B1.0 0626-0501169 (2MASS J16260214-2718141) is the optical counterpart of a Swift/XRT X-ray source that was originally proposed to be the counterpart of an ANTARES neutrino detection (ATEL #7987).

  18. [The influence of the water potential in the root-habitable area on the efficiency of the higher-order plants].

    PubMed

    Berkovich, Iu A; Krivobok, N M; Smolianina, S O; Ivanov, V B; Zhilenkova, O G; Bol'shakova, L S

    1999-01-01

    In a set of 8 experiments, in leaf mustard Brassica junceae L. (cult. Volnushka) and in soft wheat Triticum aestivum L. (cult. Super Dwarf) there has been studied dynamics of accumulating biomass in the ontogenesis in accordance with the value of water potential in the root-habitable medium. Besides, in wheat there has been investigated the process of forming the grain crop capacity in a period between V and XII stages of the organogenesis from Kuperman's classification. The plants have been grown in the root modules with the perlite used as a substitute for soil and with water supply through the porous hydrophilic membranes. The levels of water potential in the root-habitable medium, namely in the perlite, were kept unchanged in the range from -0.5 to -13 kPa (or from -5 to -130 cm water column) which corresponded to volumetric humidity ranged from 63 to 25%. Tests exposition was in the range of 13 to 78 and 25 to 46 days for wheat and mustard, respectively. The value of upper limit of an allowable water potential was determined from the magnitude of critical pressure of the puncture at which the most large through pores in the perlite layer break free of water, the value of lower limit was determined after criterion of a significant decrease in the plants harvest. In accordance with the paper results an allowable range of water potential in a perlite-based root-habitable medium ranged from -1.0 to -2.0 kPa which was in agreement with the range of volume humidity from 61% to 51%. In decreasing the water potential beyond the lower limit of mentioned range to -3.0 kPa, the mass of mustard shoots has reduced by 30% and the wheat crop was not good. The elaborated procedure and equipment can be used for determining the thresholds of permissible water potentials (humidity) for any soil substitutes irrespective of the construction of root module and the species of cultivated plants. PMID:10399556

  19. Fungitoxicity of some higher plants and synergistic activity of their essential oils against Sclerotium rolfsii sacc. causing foot-rot disease of barley.

    PubMed

    Singh, R K

    Twenty five plant species were screened for their volatile components against hyphal growth and sclerotia formation of Sclerotium rolfsii causing foot rot disease of barley (Hordeum vulgare). Leaves of Chenopodium ambrosioides (CA), Lippia alba (LA), Azadirachta indica (AI) and Eucalyptus globulus (EG) were found to be strongly toxic. Their volatile active factors were isolated in the form of essential oils which were tested for toxicity individually and in six combinations (1:1 v/v) viz. CA-LA, LA-AI, CA-AI, CA-EG, and EG-AI. The oil combinations were found to be more fungitoxic than the individual oils. The CA-LA, LA-AI, EG-AI, and CA-EG combinations exhibited a broad fnngitoxic spectrum while CA-AI, LA-EG combinations possessed a narrow range of toxicity. None of the six oil combinations showed phytotoxic behaviour on seed germination, seedling growth and general morphology of Hordeum vulgare. PMID:18697732

  20. (Molecular studies of functional aspects of higher plant mitochrondria): Annual progress report covering the period August 1, 1987--March 15, 1988

    SciTech Connect

    Siedow, J.N.

    1988-01-01

    A 13 kDa protein, encoded by a gene specifically associated with the mitochondrial genome of Zea maize containing the cms-T trait, has been correlated susceptibility of maize to infection by the fungal pathogen, Biopolaris maydis, race T. Additional work had indicated that mitochondria from cms-T plants were specifically sensitive to BmT toxin produced by this fungus, such that addition of BmT toxin to cms-T maize mitochondria induced a massive leakage of low molecular weight. The gene encoding the 13 kDa polypeptide (urf13-T) was cloned into E. coli using the pATH-3 expression vector under control of the trp promoter.

  1. Functional characterization of a higher plant sphingolipid Delta4-desaturase: defining the role of sphingosine and sphingosine-1-phosphate in Arabidopsis.

    PubMed

    Michaelson, Louise V; Zäuner, Simone; Markham, Jonathan E; Haslam, Richard P; Desikan, Radhika; Mugford, Sarah; Albrecht, Sandra; Warnecke, Dirk; Sperling, Petra; Heinz, E; Napier, Johnathan A

    2009-01-01

    The role of Delta4-unsaturated sphingolipid long-chain bases such as sphingosine was investigated in Arabidopsis (Arabidopsis thaliana). Identification and functional characterization of the sole Arabidopsis ortholog of the sphingolipid Delta4-desaturase was achieved by heterologous expression in Pichia pastoris. A P. pastoris mutant disrupted in the endogenous sphingolipid Delta4-desaturase gene was unable to synthesize glucosylceramides. Synthesis of glucosylceramides was restored by the expression of Arabidopsis gene At4g04930, and these sphingolipids were shown to contain Delta4-unsaturated long-chain bases, confirming that this open reading frame encodes the sphingolipid Delta4-desaturase. At4g04930 has a very restricted expression pattern, transcripts only being detected in pollen and floral tissues. Arabidopsis insertion mutants disrupted in the sphingolipid Delta4-desaturase At4g04930 were isolated and found to be phenotypically normal. Sphingolipidomic profiling of a T-DNA insertion mutant indicated the absence of Delta4-unsaturated sphingolipids in floral tissue, also resulting in the reduced accumulation of glucosylceramides. No difference in the response to drought or water loss was observed between wild-type plants and insertion mutants disrupted in the sphingolipid Delta4-desaturase At4g04930, nor was any difference observed in stomatal closure after treatment with abscisic acid. No differences in pollen viability between wild-type plants and insertion mutants were detected. Based on these observations, it seems unlikely that Delta4-unsaturated sphingolipids and their metabolites such as sphingosine-1-phosphate play a significant role in Arabidopsis growth and development. However, Delta4-unsaturated ceramides may play a previously unrecognized role in the channeling of substrates for the synthesis of glucosylceramides. PMID:18978071

  2. Functional Characterization of a Higher Plant Sphingolipid Δ4-Desaturase: Defining the Role of Sphingosine and Sphingosine-1-Phosphate in Arabidopsis1[W][OA

    PubMed Central

    Michaelson, Louise V.; Zäuner, Simone; Markham, Jonathan E.; Haslam, Richard P.; Desikan, Radhika; Mugford, Sarah; Albrecht, Sandra; Warnecke, Dirk; Sperling, Petra; Heinz, E.; Napier, Johnathan A.

    2009-01-01

    The role of Δ4-unsaturated sphingolipid long-chain bases such as sphingosine was investigated in Arabidopsis (Arabidopsis thaliana). Identification and functional characterization of the sole Arabidopsis ortholog of the sphingolipid Δ4-desaturase was achieved by heterologous expression in Pichia pastoris. A P. pastoris mutant disrupted in the endogenous sphingolipid Δ4-desaturase gene was unable to synthesize glucosylceramides. Synthesis of glucosylceramides was restored by the expression of Arabidopsis gene At4g04930, and these sphingolipids were shown to contain Δ4-unsaturated long-chain bases, confirming that this open reading frame encodes the sphingolipid Δ4-desaturase. At4g04930 has a very restricted expression pattern, transcripts only being detected in pollen and floral tissues. Arabidopsis insertion mutants disrupted in the sphingolipid Δ4-desaturase At4g04930 were isolated and found to be phenotypically normal. Sphingolipidomic profiling of a T-DNA insertion mutant indicated the absence of Δ4-unsaturated sphingolipids in floral tissue, also resulting in the reduced accumulation of glucosylceramides. No difference in the response to drought or water loss was observed between wild-type plants and insertion mutants disrupted in the sphingolipid Δ4-desaturase At4g04930, nor was any difference observed in stomatal closure after treatment with abscisic acid. No differences in pollen viability between wild-type plants and insertion mutants were detected. Based on these observations, it seems unlikely that Δ4-unsaturated sphingolipids and their metabolites such as sphingosine-1-phosphate play a significant role in Arabidopsis growth and development. However, Δ4-unsaturated ceramides may play a previously unrecognized role in the channeling of substrates for the synthesis of glucosylceramides. PMID:18978071

  3. Soil-plant N processes in a High Arctic ecosystem, NW Greenland are altered by long-term experimental warming and higher rainfall.

    PubMed

    Schaeffer, Sean M; Sharp, Elizabeth; Schimel, Joshua P; Welker, Jeffery M

    2013-11-01

    Rapid temperature and precipitation changes in High Arctic tundra ecosystems are altering the biogeochemical cycles of carbon (C) and nitrogen (N), but in ways that are difficult to predict. The challenge grows from the uncertainty of N cycle responses and the extent to which shifts in soil N are coupled with the C cycle and productivity of tundra systems. We used a long-term (since 2003) experiment of summer warming and supplemental summer water additions to a High Arctic ecosystem in NW Greenland, and applied a combination of discrete sampling and in situ soil core incubations to measure C and N pools and seasonal microbial processes that might control plant-available N. We hypothesized that elevated temperature and increased precipitation would stimulate microbial activity and net inorganic N mineralization, thereby increasing plant N-availability through the growing season. While we did find increased N mineralization rates under both global change scenarios, water addition also significantly increased net nitrification rates, loss of NO3 (-) -N via leaching, and lowered rates of labile organic N production. We also expected the chronic warming and watering would lead to long-term changes in soil N-cycling that would be reflected in soil δ(15) N values. We found that soil δ(15) N decreased under the different climate change scenarios. Our results suggest that temperature accelerates biological processes and existing C and N transformations, but moisture increases soil hydraulic connectivity and so alters the pathways, and changes the fate of the products of C and N transformations. In addition, our findings indicate that warmer, wetter High Arctic tundra will be cycling N and C in ways that may transform these landscapes in part leading to greater C sequestration, but simultaneously, N losses from the upper soil profile that may be transported to depth dissolved in water and or transported off site in lateral flow. PMID:23843128

  4. Biological Properties of Plant-Derived Alkylresorcinols: Mini-Review.

    PubMed

    Luís, Ângelo; Domingues, Fernanda; Duarte, Ana Paula

    2016-01-01

    Alkylresorcinols are compounds which belong to the family of phenolic lipids, and are usually found in numerous biological species. In the particular case of higher plants, alkylresorcinols have been found in various counterparts with chains of thirteen to twenty-seven carbon atoms containing several saturations. Due to the demonstrated antimicrobial properties of many naturally occurring members of the alkylresorcinols family, it is possible to conclude that these compounds act as defensive agents in plants. Previous studies led to the isolation and identification of 5-alkylresorcinols that cleave DNA. Additionally, in the literature, there are several other biological effects attributed to some resorcinol derivatives, namely, cytotoxic, anticarcinogenic, antiproliferative, antileishmanial and antioxidant properties. This mini-review intends to outline the biological activities of the most relevant alkylresorcinols isolated from plants and to propose future directions for subsequent studies regarding the effective biological effects of this class of compounds. PMID:26864549

  5. Interstellar Scintillation and the Radio Counterpart of the Fast Radio Burst FRB 150418

    NASA Astrophysics Data System (ADS)

    Akiyama, Kazunori; Johnson, Michael D.

    2016-06-01

    Keane et al. have recently reported the discovery of a new fast radio burst (FRB), FRB 150418, with a promising radio counterpart at 5.5 and 7.5 GHz—a rapidly decaying source, falling from 200–300 μJy to 100 μJy on timescales of ˜6 days. This transient source may be associated with an elliptical galaxy at redshift z = 0.492, providing the first firm spectroscopic redshift for an FRB and the ability to estimate the density of baryons in the intergalactic medium via the combination of known redshift and radio dispersion of the FRB. An alternative explanation, first suggested by Williams & Berger, is that the identified counterpart may instead be a compact active galactic nucleus (AGN). The putative counterpart’s variation may then instead be extrinsic, caused by refractive scintillation in the ionized interstellar medium of the Milky Way, which would invalidate the association with FRB 150418. We examine this latter explanation in detail and show that the reported observations are consistent with scintillating radio emission from the core of a radio-loud AGN having a brightness temperature T b ≳ 109 K. Using numerical simulations of the expected scattering for the line of sight to FRB 150418, we provide example images and light curves of such an AGN at 5.5 and 7.5 GHz. These results can be compared with continued radio monitoring to conclusively determine the importance of scintillation for the observed radio variability, and they show that scintillation is a critical consideration for continued searches for FRB counterparts at radio wavelengths.

  6. Interstellar Scintillation and the Radio Counterpart of the Fast Radio Burst FRB 150418

    NASA Astrophysics Data System (ADS)

    Akiyama, Kazunori; Johnson, Michael D.

    2016-06-01

    Keane et al. have recently reported the discovery of a new fast radio burst (FRB), FRB 150418, with a promising radio counterpart at 5.5 and 7.5 GHz—a rapidly decaying source, falling from 200–300 μJy to 100 μJy on timescales of ∼6 days. This transient source may be associated with an elliptical galaxy at redshift z = 0.492, providing the first firm spectroscopic redshift for an FRB and the ability to estimate the density of baryons in the intergalactic medium via the combination of known redshift and radio dispersion of the FRB. An alternative explanation, first suggested by Williams & Berger, is that the identified counterpart may instead be a compact active galactic nucleus (AGN). The putative counterpart’s variation may then instead be extrinsic, caused by refractive scintillation in the ionized interstellar medium of the Milky Way, which would invalidate the association with FRB 150418. We examine this latter explanation in detail and show that the reported observations are consistent with scintillating radio emission from the core of a radio-loud AGN having a brightness temperature T b ≳ 109 K. Using numerical simulations of the expected scattering for the line of sight to FRB 150418, we provide example images and light curves of such an AGN at 5.5 and 7.5 GHz. These results can be compared with continued radio monitoring to conclusively determine the importance of scintillation for the observed radio variability, and they show that scintillation is a critical consideration for continued searches for FRB counterparts at radio wavelengths.

  7. LONG-DURATION RADIO TRANSIENTS LACKING OPTICAL COUNTERPARTS ARE POSSIBLY GALACTIC NEUTRON STARS

    SciTech Connect

    Ofek, E. O.; Kasliwal, M. M.; Kulkarni, S. R.; Breslauer, B.; Gal-Yam, A.; Waxman, E.; Frail, D.

    2010-03-01

    Recently, a new class of radio transients in the 5 GHz band and with durations of the order of hours to days, lacking any visible-light counterparts, was detected by Bower and collaborators. We present new deep near-infrared (IR) observations of the field containing these transients, and find no counterparts down to a limiting magnitude of K = 20.4 mag. We argue that the bright (>1 Jy) radio transients recently reported by Kida et al. are consistent with being additional examples of the Bower et al. transients. We refer to these groups of events as 'long-duration radio transients'. The main characteristics of this population are: timescales longer than 30 minutes but shorter than several days; very large rate, {approx}10{sup 3} deg{sup -2} yr{sup -1}; progenitor's sky surface density of >60 deg{sup -2} (at 95% confidence) at Galactic latitude {approx}40{sup 0}; 1.4-5 GHz spectral slopes, f{sub n}u {proportional_to} nu{sup alpha}, with alpha {approx}> 0; and most notably the lack of any X-ray, visible-light, near-IR, and radio counterparts in quiescence. We discuss putative known astrophysical objects that may be related to these transients and rule out an association with many types of objects including supernovae, gamma-ray bursts, quasars, pulsars, and M-dwarf flare stars. Galactic brown dwarfs or some sort of exotic explosions in the intergalactic medium remain plausible (though speculative) options. We argue that an attractive progenitor candidate for these radio transients is the class of Galactic isolated old neutron stars (NSs). We confront this hypothesis with Monte Carlo simulations of the space distribution of old NSs, and find satisfactory agreement for the large areal density. Furthermore, the lack of quiescent counterparts is explained quite naturally. In this framework, we find: the mean distance to events in the Bower et al. sample is of order kpc; the typical distance to the Kida et al. transients are constrained to be between 45 pc and 2 kpc (at

  8. HST/ACS IMAGING OF OMEGA CENTAURI: OPTICAL COUNTERPARTS OF CHANDRA X-RAY SOURCES

    SciTech Connect

    Cool, Adrienne M.; Arias, Tersi; Brochmann, Michelle; Dorfman, Jason; Gafford, April; White, Vivian; Haggard, Daryl; Anderson, Jay E-mail: dhaggard@northwestern.edu

    2013-02-15

    We present results of a search for optical counterparts of X-ray sources in and toward the globular cluster Omega Centauri (NGC 5139) using the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope. The ACS data consist of a mosaic of Wide Field Channel images obtained using F625W, F435W, and F658N filters; with nine pointings we cover the central {approx}10' Multiplication-Sign 10' of the cluster and encompass 109 known Chandra sources. We find promising optical counterparts for 59 of the sources, {approx}40 of which are likely to be associated with the cluster. These include 27 candidate cataclysmic variables (CVs), 24 of which are reported here for the first time. Fourteen of the CV candidates are very faint, with absolute magnitudes in the range M {sub 625} =10.4-12.6, making them comparable in brightness to field CVs near the period minimum discovered in the Sloan Digital Sky Survey. Additional optical counterparts include three BY Dra candidates, a possible blue straggler, and a previously reported quiescent low-mass X-ray binary. We also identify 3 foreground stars and 11 probable active galactic nuclei. Finally, we report the discovery of a group of seven stars whose X-ray properties are suggestive of magnetically active binaries, and whose optical counterparts lie on or very near the metal-rich anomalous giant and subgiant branches in {omega} Cen. If the apparent association between these seven stars and the RGB/SGB-a stars is real, then the frequency of X-ray sources in this metal-rich population is enhanced by a factor of at least five relative to the other giant and subgiant populations in the cluster. If these stars are not members of the metal-rich population, then they bring the total number of red stragglers (also known as sub-subgiants) that have been identified in {omega} to Cen 20, the largest number yet known in any globular cluster.

  9. The optical counterpart to the large H I cloud in Virgo

    SciTech Connect

    Salzer, J.J.; Di serego alighieri, S.; Matteucci, F.; Giovanelli, R.; Haynes, M.P. European Southern Observatory, Garching, CNR, Istituto di Astrofisica Spaziale, Frascati Cornell Univ., Ithaca, NY )

    1991-04-01

    Detailed imaging and spectroscopic observations of the optical counterpart to H I 1225 + 01 are reported, as are the results of 2.6-mm CO observations. Nebular abundances are derived, and a number of models are presented in an attempt to account for both the chemical and photometric color evolution of this galaxy. The physical properties of the galaxy are then discussed, and various scenarios for its evolutionary status are considered by comparing the observed parameters with model predictions and similar quantities for other galaxies. 72 refs.

  10. Recent studies of the optical counterpart of GX 1+4

    NASA Astrophysics Data System (ADS)

    Sharma, D. P.; Sood, R. K.; Stringfellow, G.; James, S. D.; Hill, K. M.; Manchanda, R. K.

    1993-12-01

    The galactic X-ray source GX 1+4 has been undergoing remarkable changes since early 1991. The X-ray pulsar has shown fast spin down accompanied by an increase in the hard X-ray intensity. We have obtained 1.6A resolution spectra of the optical counterpart extending the known spectrum to 8500A. The Ca II (8498A) line seen for the first time from this source is indicative of a nova burst scenario. Other lines detected for the first time are detailed and the significance of these features is discussed.

  11. A study of the far infrared counterparts of new candidates for planetary nebulae

    NASA Astrophysics Data System (ADS)

    Iyengar, K. V. K.

    1986-05-01

    The IRAS Point Source Catalog was searched for infrared counterparts of the fourteen new candidates for planetary nebulae of low surface brightness detected by Hartl and Tritton (1985). Five of these candidates were identified with sources in the Catalog. All five nebulae are found in regions of high cirrus flux at 100 microns, and all have both point sources and small size extended sources with numbers varying from field to field. The infrared emission from these nebulae is connected with dust temperatures of about 100 K, characteristic of planetary nebulae.

  12. Fermi/LAT search for counterpart to the IceCube event 67093193 (run 127853)

    NASA Astrophysics Data System (ADS)

    Vianello, G.; Magill, J. D.; Omodei, N.; Kocevski, D.; Ajello, M.; Buson, S.; Krauss, F.; Chiang, J.

    2016-04-01

    on behalf of the Fermi-LAT team: We have searched the Fermi Large Area Telescope data for a high-energy gamma-ray counterpart for the IceCube High Energy Starting Event (HESE) 67093193, detected in run 127853 on 2016-04-27 05:52:32.00 UT (AMON GCN notice rev. 2, http://gcn.gsfc.nasa.gov/notices_amon/67093193_127853.amon . See http://gcn.gsfc.nasa.gov/doc/Public_Doc_AMON_IceCube_GCN_Alerts_v2.pdf for a description of HESE events and related GCN notices).

  13. AN APPARENTLY EXTENDED INFRARED COUNTERPART TO 1E 1740.7-2942

    SciTech Connect

    MartI, J.; Sanchez-Sutil, J. R.; Munoz-Arjonilla, A. J.; Sanchez-Ayaso, E.; Garcia-Hernandez, M. T.

    2010-10-01

    We present the results of a revised search for the near-infrared counterpart to the microquasar 1E 1740.7-2942, which has eluded identification despite the many years elapsed since its discovery. By taking into account new astrometric information, we have been successful to identify a single near-infrared source, with apparent non-stellar morphology, whose position agrees well with that of the microquasar X-ray and radio-emitting core at the subarcsecond level. The possible implications of this finding with respect to the nature of 1E 1740.7-2942 are discussed.

  14. Spectroscopic observations of the counterpart of IGR J00291+5934

    NASA Astrophysics Data System (ADS)

    Roelofs, G.; Jonker, P. G.; Steeghs, D.; Torres, M.; Nelemans, G.

    2004-12-01

    Spectroscopic observations of the optical counterpart of the millisecond X-ray pulsar IGR J00291+5934 (Atel #352, 353) reported in an Atel by Fox & Kulkarni were obtained (Dec 5 00:29-01:15 UT) with the ISIS spectrograph mounted on the 4.2m William Herschel Telescope on La Palma. Weather conditions were not optimal with a seeing of ~2" and thin clouds. The spectra show weak evidence for broad emission line features near the HeII line at 4686 Angstrom and near the Halpha line at 6563 Angstrom.

  15. Identification of a 67 kDa protein that binds specifically to the pre-rRNA primary processing site in a higher plant.

    PubMed

    Echeverria, M; Lahmy, S

    1995-12-25

    In radish pre-rRNA primary processing cleavage occurs at a UUUUCGCGC element (motif P) mapped in the 5'-external transcribed spacer (Delcasso-Tremousaygue et al., 1988). Significantly, motif P is part of a cluster of homologous elements including three UUUUCCGG elements (motifs A123) and a single UUUUGCCCC element (motif B). Here we used the EMSA to identify in radish extracts an RNA-binding activity, NF C, that specifically interacts with the pre-rRNA A123BP sequence. Using different RNA probes and competitors we show that NF C recognises a 38 base RNA sequence including the 3'-end of motif A3 and motifs B and P. NF C binds to poly U, but not to poly A, poly C or poly G. Therefore we used poly (U) Sepharose chromatography as a final step to obtain pure NF C fractions. These, analysed by SDS-PAGE, revealed two major polypeptides of 67 and 60 kDa. According to UV cross-linking analysis the 67 kDa polypeptide corresponds to NF C activity, while the 60 kDa species is a proteolysed form of this protein. We also showed that NF C is enriched in nuclear extracts. Based on its stringent RNA substrate specificity and its nuclear localisation we propose that NF C is involved in pre-rRNA primary processing in plants. PMID:8559652

  16. Higher Plant Photosystem II Light-Harvesting Antenna, Not the Reaction Center, Determines the Excited-State Lifetime—Both the Maximum and the Nonphotochemically Quenched

    PubMed Central

    Belgio, Erica; Johnson, Matthew P.; Jurić, Snježana; Ruban, Alexander V.

    2012-01-01

    The maximum chlorophyll fluorescence lifetime in isolated photosystem II (PSII) light-harvesting complex (LHCII) antenna is 4 ns; however, it is quenched to 2 ns in intact thylakoid membranes when PSII reaction centers (RCIIs) are closed (Fm). It has been proposed that the closed state of RCIIs is responsible for the quenching. We investigated this proposal using a new, to our knowledge, model system in which the concentration of RCIIs was highly reduced within the thylakoid membrane. The system was developed in Arabidopsis thaliana plants under long-term treatment with lincomycin, a chloroplast protein synthesis inhibitor. The treatment led to 1), a decreased concentration of RCIIs to 10% of the control level and, interestingly, an increased antenna component; 2), an average reduction in the yield of photochemistry to 0.2; and 3), an increased nonphotochemical chlorophyll fluorescence quenching (NPQ). Despite these changes, the average fluorescence lifetimes measured in Fm and Fm′ (with NPQ) states were nearly identical to those obtained from the control. A 77 K fluorescence spectrum analysis of treated PSII membranes showed the typical features of preaggregation of LHCII, indicating that the state of LHCII antenna in the dark-adapted photosynthetic membrane is sufficient to determine the 2 ns Fm lifetime. Therefore, we conclude that the closed RCs do not cause quenching of excitation in the PSII antenna, and play no role in the formation of NPQ. PMID:22735526

  17. Sodium-Dependent Nitrate Transport at the Plasma Membrane of Leaf Cells of the Marine Higher Plant Zostera marina L.1

    PubMed Central

    García-Sánchez, María J.; Jaime, M. Paz; Ramos, Alberto; Sanders, Dale; Fernández, José A.

    2000-01-01

    NO3− is present at micromolar concentrations in seawater and must be absorbed by marine plants against a steep electrochemical potential difference across the plasma membrane. We studied NO3− transport in the marine angiosperm Zostera marina L. to address the question of how NO3− uptake is energized. Electrophysiological studies demonstrated that micromolar concentrations of NO3− induced depolarizations of the plasma membrane of leaf cells. Depolarizations showed saturation kinetics (Km = 2.31 ± 0.78 μm NO3−) and were enhanced in alkaline conditions. The addition of NO3− did not affect the membrane potential in the absence of Na+, but depolarizations were restored when Na+ was resupplied. NO3−-induced depolarizations at increasing Na+ concentrations showed saturation kinetics (Km = 0.72 ± 0.18 mm Na+). Monensin, an ionophore that dissipates the Na+ electrochemical potential, inhibited NO3−-evoked depolarizations by 85%, and NO3− uptake (measured by depletion from the external medium) was stimulated by Na+ ions and by light. Our results strongly suggest that NO3− uptake in Z. marina is mediated by a high-affinity Na+-symport system, which is described here (for the first time to our knowledge) in an angiosperm. Coupling the uptake of NO3− to that of Na+ enables the steep inwardly-directed electrochemical potential for Na+ to drive net accumulation of NO3− within leaf cells. PMID:10712552

  18. Light microscopic analysis of the three-dimensional structure of higher plant chloroplasts. Position of starch grains and probable spiral arrangement of stroma lamellae and grana

    SciTech Connect

    Wildman, S.G.; Jope, C.A.; Atchison, B.A.

    1980-03-01

    Light microscopic observations of grana-containing chloroplasts in living cells of leaves of numerous species of plants, including both monocotyledons and dicotyledons, have allowed specification of numerous parameters of chloroplast structure. Chloroplasts are thin and saucer-shaped, with the convex surface facing the cell wall and the concave surface facing the vacuole. The thickness of the grana-containing and starch-containing region of chloroplasts does not exceed 2 ..mu..m although the length may reach more than 15 ..mu..m in chloroplasts containing 150 grana. The grana do not overlap each other and are in a plane of focus above that of the starch grains. The grana are tilted with respect to each other and are located at varying levels with respect to the convex surface of the chloroplast. In slightly disrupted, isolated chloroplasts, the grana are sometimes arranged in rows and serially connected to each other by a fine thread. In living cells, some chloroplasts exhibit a distinct spiral arrangement of the grana. Using these observations and the dimensions derived from them, a new conception of the three-dimensional structure of the grana-containing region of the chloroplast has been obtained. In this conception, the grana are uniformly thin, nonoverlapping cylinders, connected in a single series as in a string of beads and wound into a slightly raised spiral (a helix). Starch grains, when present, are located in the concavity of the helix. The length of the string of grana determines the area of the grana-containing region of a chloroplast.

  19. Induced Release of a Plant-Defense Volatile ‘Deceptively’ Attracts Insect Vectors to Plants Infected with a Bacterial Pathogen

    PubMed Central

    Mann, Rajinder S.; Ali, Jared G.; Hermann, Sara L.; Tiwari, Siddharth; Pelz-Stelinski, Kirsten S.; Alborn, Hans T.; Stelinski, Lukasz L.

    2012-01-01

    Transmission of plant pathogens by insect vectors is a complex biological process involving interactions between the plant, insect, and pathogen. Pathogen-induced plant responses can include changes in volatile and nonvolatile secondary metabolites as well as major plant nutrients. Experiments were conducted to understand how a plant pathogenic bacterium, Candidatus Liberibacter asiaticus (Las), affects host preference behavior of its psyllid (Diaphorina citri Kuwayama) vector. D. citri were attracted to volatiles from pathogen-infected plants more than to those from non-infected counterparts. Las-infected plants were more attractive to D. citri adults than non-infected plants initially; however after feeding, psyllids subsequently dispersed to non-infected rather than infected plants as their preferred settling point. Experiments with Las-infected and non-infected plants under complete darkness yielded similar results to those recorded under light. The behavior of psyllids in response to infected versus non-infected plants was not influenced by whether or not they were carriers of the pathogen. Quantification of volatile release from non-infected and infected plants supported the hypothesis that odorants mediate psyllid preference. Significantly more methyl salicylate, yet less methyl anthranilate and D-limonene, was released by infected than non-infected plants. Methyl salicylate was attractive to psyllids, while methyl anthranilate did not affect their behavior. Feeding on citrus by D. citri adults also induced release of methyl salicylate, suggesting that it may be a cue revealing location of conspecifics on host plants. Infected plants were characterized by lower levels of nitrogen, phosphorus, sulfur, zinc, and iron, as well as, higher levels of potassium and boron than non-infected plants. Collectively, our results suggest that host selection behavior of D. citri may be modified by bacterial infection of plants, which alters release of specific headspace

  20. Discovery of near-ultraviolet counterparts to millisecond pulsars in the globular cluster 47 Tucanae

    NASA Astrophysics Data System (ADS)

    Rivera-Sandoval, L. E.; van den Berg, M.; Heinke, C. O.; Cohn, H. N.; Lugger, P. M.; Freire, P.; Anderson, J.; Serenelli, A. M.; Althaus, L. G.; Cool, A. M.; Grindlay, J. E.; Edmonds, P. D.; Wijnands, R.; Ivanova, N.

    2015-11-01

    We report the discovery of the likely white dwarf companions to radio millisecond pulsars 47 Tuc Q and 47 Tuc S in the globular cluster 47 Tucanae. These blue stars were found in near-ultraviolet images from the Hubble Space Telescope for which we derived accurate absolute astrometry, and are located at positions consistent with the radio coordinates to within 0.016 arcsec (0.2σ). We present near-ultraviolet and optical colours for the previously identified companion to millisecond pulsar 47 Tuc U, and we unambiguously confirm the tentative prior identifications of the optical counterparts to 47 Tuc T and 47 Tuc Y. For the latter, we present its radio-timing solution for the first time. We find that all five near-ultraviolet counterparts have U300 - B390 colours that are consistent with He white dwarf cooling models for masses ˜0.16-0.3 M⊙ and cooling ages within ˜0.1-6 Gyr. The Hα - R625 colours of 47 Tuc U and 47 Tuc T indicate the presence of a strong Hα absorption line, as expected for white dwarfs with an H envelope.

  1. THE VARIABLE NEAR-INFRARED COUNTERPART OF THE MICROQUASAR GRS 1758–258

    SciTech Connect

    Luque-Escamilla, Pedro L.

    2014-12-10

    We present a new study of the microquasar system GRS 1758–258 in the near-infrared domain based on archival observations with the Hubble Space Telescope and the NICMOS camera. In addition to confirming the near-infrared counterpart pointed out by Muñoz-Arjonilla et al., we show that this object displays significant photometric variability. From its average magnitudes, we also find that GRS 1758–258 fits well within the correlation between the optical/near-infrared and X-ray luminosity known to exist for low-mass, black-hole candidate X-ray binaries in a hard state. Moreover, the spectral energy distribution built using all radio, near-infrared, and X-ray data available closest in time to the NICMOS observations can be reasonably interpreted in terms of a self-absorbed radio jet and an irradiated accretion disk model around a stellar-mass black hole. All these facts match the expected behavior of a compact binary system and strengthen our confidence in the counterpart identification.

  2. Motor skills in Czech children with attention-deficit/hyperactivity disorder and their neurotypical counterparts.

    PubMed

    Scharoun, S M; Bryden, P J; Otipkova, Z; Musalek, M; Lejcarova, A

    2013-11-01

    Attention-deficit/hyperactivity disorder (ADHD) is the most commonly diagnosed neurobehavioural disorder. Characterized by recurring problems with impulsiveness and inattention in combination with hyperactivity, motor impairments have also been well documented in the literature. The aim of this study was to compare the fine and gross motor skills of male and female children with ADHD and their neurotypical counterparts within seven skill assessments. This included three fine motor tasks: (1) spiral tracing, (2) dot filling, (3) tweezers and beads; and four gross motor tasks: (1) twistbox, (2) foot tapping, (3) small plate finger tapping, and (4) large plate finger tapping. It was hypothesized that children with ADHD would display poorer motor skills in comparison to neurotypical controls in both fine and gross motor assessments. However, statistically significant differences between the groups only emerged in four of the seven tasks (spiral tracing, dot filling, tweezers and beads and foot tapping). In line with previous findings, the complexity underlying upper limb tasks solidified the divide in performance between children with ADHD and their neurotypical counterparts. In light of similar research, impairments in lower limb motor skill were also observed. Future research is required to further delineate trends in motor difficulties in ADHD, while further investigating the underlying mechanisms of impairment. PMID:24060728

  3. Low energy electron induced reactions in fluorinated acetamide - probing negative ions and neutral stable counterparts*

    NASA Astrophysics Data System (ADS)

    Kopyra, Janina; König-Lehmann, Constanze; Illenberger, Eugen; Warneke, Jonas; Swiderek, Petra

    2016-06-01

    Electron impact to trifluoroacetamide (CF3CONH2, TFAA) in the energy range 0-12 eV leads to a variety of negative fragment ions which are formed via dissociative electron attachment (DEA). The underlying reactions range from single bond cleavages to remarkably complex reactions that lead to loss of the neutral units HF, H2O and HNCO as deduced from their directly observed ionic counterparts (M - H2O)-, (M - HF)- and (M - HNCO)-. Also formed are the pseudo-halogen ions CN- and OCN-. All these reactions proceed dominantly via a resonance located near 1 eV, i.e., electrons at subexcitation energies trigger reactions involving multiple bond cleavages. The electron induced generation of the neutral molecules HF, H2O and HNCO in condensed TFAA films is probed by temperature controlled thermal desorption spectrometry (TDS) which can be viewed as a complementary techniques to gas-phase experiments in DEA to directly probe the neutral counterparts. Contribution to the Topical Issue "Advances in Positron and Electron Scattering", edited by Paulo Limao-Vieira, Gustavo Garcia, E. Krishnakumar, James Sullivan, Hajime Tanuma and Zoran Petrovic.

  4. A Candidate Optical Counterpart to the Middle Aged γ-RAY Pulsar PSRJ1741–2054

    NASA Astrophysics Data System (ADS)

    Mignani, R. P.; Testa, V.; Marelli, M.; De Luca, A.; Salvetti, D.; Belfiore, A.; Pierbattista, M.; Razzano, M.; Shearer, A.; Moran, P.

    2016-07-01

    We carried out deep optical observations of the middle aged γ-ray pulsar PSR J1741‑2054 with the Very Large Telescope (VLT). We identified two objects, of magnitudes m v = 23.10 ± 0.05 and m v = 25.32 ± 0.08, at positions consistent with the very accurate Chandra coordinates of the pulsar, the faintest of which is more likely to be its counterpart. From the VLT images we also detected the known bow-shock nebula around PSR J1741‑2054. The nebula is displaced by ∼0.″9 (at the 3σ confidence level) with respect to its position measured in archival data, showing that the shock propagates in the interstellar medium consistently with the pulsar proper motion. Finally, we could not find evidence of large-scale extended optical emission associated with the pulsar wind nebula detected by Chandra, down to a surface brightness limit of ∼28.1 mag arcsec‑2. Future observations are needed to confirm the optical identification of PSR J1741‑2054 and characterize the spectrum of its counterpart. Based on observations collected at the European Organization for Astronomical Research in the Southern Hemisphere under ESO programme 095.D-0328(B).

  5. Variable ASAS Counterparts to Galactic Bulge Survey X-ray Sources

    NASA Astrophysics Data System (ADS)

    Gabb, Monique; Hynes, R. I.; Britt, C.; Johnson, C. C.; Jonker, P.; Torres, M.; Maccarone, T.; Steeghs, D.; Greiss, S.; Nelemans, G.; Galactic Bulge Survey Collaboration

    2013-01-01

    The Galactic Bulge Survey (GBS) is a shallow Chandra X-ray survey of two 6x1 degree strips located 1 degree above and below the Galactic Plane. After removing duplicates, the final GBS catalogue has 1640 unique X-ray sources. The goal of the survey is to test binary evolution models and increase the number of known Low Mass X-ray Binaries, in order to investigate questions such as the distribution of black hole mass and constrain the equation of state of neutron stars. We aim to identify all variable optical counterparts to the X-ray sources and analyze their periods. This lightcurve information, along with other multi-wavelength observations, enables the classifications of these GBS sources. Many of the GBS X-ray sources coincide with stars in the All Sky Automated Survey (ASAS). We report here on variable counterparts to GBS sources identified within the ASAS dataset, examine their characteristics, and discuss their likely classification. This work is supported by the National Science Foundation under Grant No. AST-0908789. Monique Gabb also acknowledges support from the REU Site in Physics and Astronomy (NSF Grant No. 1004822) at Louisiana State University.

  6. An X-Ray Counterpart of HESS J1427-608 Discovered with Suzaku

    NASA Astrophysics Data System (ADS)

    Fujinaga, Takahisa; Mori, Koji; Bamba, Aya; Kimura, Shoichi; Dotani, Tadayasu; Ozaki, Masanobu; Matsuta, Keiko; Pülhofer, Gerd; Uchiyama, Hideki; Hiraga, Junko S.; Matsumoto, Hironori; Terada, Yukikatsu

    2013-06-01

    We report on the discovery of an X-ray counterpart of the unidentified very high-energy gamma-ray source HESS J1427-608. In the sky field coincident with HESS J1427-608, an extended source was found in the 2-8 keV band, and was designated as Suzaku J1427-6051. Its X-ray radial profile has an extension of σ = 0.'9 ± 0.'1 if approximated by a Gaussian. The spectrum was well fitted by an absorbed power-law with NH = (1.1 ± 0.3) × 1023 cm-2, Γ = 3.1+0.6-0.5, and the unabsorbed flux FX = (9+4-2) × 10-13 erg s-1 cm-2 in the 2-10 keV band. Using XMM-Newton archive data, we found seven point sources in the Suzaku source region. However, because their total flux and absorbing column densities are more than an order of magnitude lower than those of Suzaku J1427-6051, we consider that they are unrelated to the Suzaku source. Thus, Suzaku J1427-6051 is considered to be a truly diffuse source and an X-ray counterpart of HESS J1427-608. The possible nature of HESS J1427-608 is discussed based on the observational properties.

  7. THE FERMI HAZE: A GAMMA-RAY COUNTERPART TO THE MICROWAVE HAZE

    SciTech Connect

    Dobler, Gregory; Finkbeiner, Douglas P.; Slatyer, Tracy; Cholis, Ilias; Weiner, Neal

    2010-07-10

    The Fermi Gamma-ray Space Telescope reveals a diffuse inverse Compton (IC) signal in the inner Galaxy with a similar spatial morphology to the microwave haze observed by WMAP, supporting the synchrotron interpretation of the microwave signal. Using spatial templates, we regress out {pi}{sup 0} gammas, as well as IC and bremsstrahlung components associated with known soft-synchrotron counterparts. We find a significant gamma-ray excess toward the Galactic center with a spectrum that is significantly harder than other sky components and is most consistent with IC from a hard population of electrons. The morphology and spectrum are consistent with it being the IC counterpart to the electrons which generate the microwave haze seen at WMAP frequencies. In addition, the implied electron spectrum is hard; electrons accelerated in supernova shocks in the disk which then diffuse a few kpc to the haze region would have a softer spectrum. We describe the full-sky Fermi maps used in this analysis and make them available for download.

  8. THE IDENTIFICATION OF THE X-RAY COUNTERPART TO PSR J2021+4026

    SciTech Connect

    Weisskopf, Martin C.; Elsner, Ronald F.; O'Dell, Stephen L.; Tennant, Allyn F.; Romani, Roger W.; Razzano, Massimiliano; Belfiore, Andrea; Saz Parkinson, Pablo; Ziegler, Marcus; Dormody, Michael; Ray, Paul S.; Kerr, Matthew; Harding, Alice; Swartz, Douglas A.; Carraminana, Alberto; Becker, Werner; Kanbach, Gottfried; De Luca, Andrea; Thompson, David J.

    2011-12-10

    We report the probable identification of the X-ray counterpart to the {gamma}-ray pulsar PSR J2021+4026 using imaging with the Chandra X-ray Observatory Advanced CCD Imaging Spectrometer and timing analysis with the Fermi satellite. Given the statistical and systematic errors, the positions determined by both satellites are coincident. The X-ray source position is R.A. 20{sup h}21{sup m}30.{sup s}733, decl. +40 Degree-Sign 26'46.''04 (J2000) with an estimated uncertainty of 1.''3 combined statistical and systematic error. Moreover, both the X-ray to {gamma}-ray and the X-ray to optical flux ratios are sensible assuming a neutron star origin for the X-ray flux. The X-ray source has no cataloged infrared-to-visible counterpart and, through new observations, we set upper limits to its optical emission of i' > 23.0 mag and r' > 25.2 mag. The source exhibits an X-ray spectrum with most likely both a power law and a thermal component. We also report on the X-ray and visible light properties of the 43 other sources detected in our Chandra observation.

  9. The near-infrared counterpart of a variable galactic plane radio source

    NASA Technical Reports Server (NTRS)

    Margon, Bruce; Phillips, Andrew C.; Ciardullo, Robin; Jacoby, George H.

    1992-01-01

    A near-infrared counterpart to the highly variable, unresolved galactic plane radio source GT 0116 + 622 is identified. This source is of particular interest, as it has been previously suggested to be the counterpart of the gamma-ray source Cas gamma-l. The present NIR and red images detect a faint, spatially extended (3 arcsec FWHM), very red object coincident with the radio position. There is complex spatial structure which may be due in part to an unrelated superposed foreground object. Observations on multiple nights show no evidence for flux variability, despite the high amplitude variability on a time-scale of days reported for the radio source. The data are consistent with an interpretation of GT 0116 + 622 as an unusually variable, obscured active galaxy at a distance of several hundred megaparsecs, although more exotic, and in particular galactic, interpretations cannot yet be ruled out. If the object is extragalactic, the previously suggested identification with the gamma-ray source would seem unlikely.

  10. Discovery of near-ultraviolet counterparts to millisecond pulsars in the globular cluster 47 Tucanae

    NASA Astrophysics Data System (ADS)

    Rivera Sandoval, Liliana E.

    2016-07-01

    Up to date 144 radio millisecond pulsars have been found in Galactic globular clusters, of which about two-thirds are in a binary. However, until recently only for 10 of those binary millisecond pulsars the companion has been firmly identified at optical wavelengths. We present the discovery of 2 likely He white dwarf companions to millisecond pulsars in the globular cluster 47 Tucanae, as well as the confirmation of 2 tentative identifications in the same cluster, using near-ultraviolet images obtained with the Hubble Space Telescope. This represents an important contribution to the total number of optical counterparts known in Galactic globular clusters so far. We have also analyzed optical observations taken with Hubble. From these images, we obtained H_α results for some of the counterparts. Based on our UV photometry and He WD cooling models we derived the ages, the masses and the bolometric luminosities for all the He WD companions. I will discuss our results and their implications in the context of the standard millisecond pulsar formation scenario.

  11. The Arecibo Methanol Maser Galactic Plane Survey. II. Statistical and Multiwavelength Counterpart Analysis

    NASA Astrophysics Data System (ADS)

    Pandian, Jagadheep D.; Goldsmith, Paul F.

    2007-11-01

    We present an analysis of the properties of the 6.7 GHz methanol maser sample detected in the Arecibo Methanol Maser Galactic Plane Survey. The distribution of the masers in the Galaxy, and statistics of their multiwavelength counterparts is consistent with the hypothesis of 6.7 GHz maser emission being associated with massive young stellar objects. Using the detection statistics of our survey, we estimate the minimum number of methanol masers in the Galaxy to be 1275. The l-v diagram of the sample shows the tangent point of the Carina-Sagittarius spiral arm to be around 49.6°, and suggests the occurrence of massive star formation along the extension of the Crux-Scutum arm. A Gaussian component analysis of the maser spectra shows the mean line width to be 0.38 km s-1, which is more than a factor of 2 larger than what has been reported in the literature. We also find no evidence that faint methanol masers have different properties than their bright counterparts.

  12. Ectopically hTERT expressing adult human mesenchymal stem cells are less radiosensitive than their telomerase negative counterpart

    SciTech Connect

    Serakinci, Nedime . E-mail: nserakinci@health.sdu.dk; Christensen, Rikke; Graakjaer, Jesper; Cairney, Claire J.; Keith, W. Nicol; Alsner, Jan; Saretzki, Gabriele; Kolvraa, Steen

    2007-03-10

    During the past several years increasing evidence indicating that the proliferation capacity of mammalian cells is highly radiosensitive, regardless of the species and the tissue of origin of the cells, has accumulated. It has also been shown that normal bone marrow cells of mice have a similar radiosensitivity to other mammalian cells so far tested. In this study, we investigated the genetic effects of ionizing radiation (2.5-15 Gy) on normal human mesenchymal stem cells and their telomerised counterpart hMSC-telo1. We evaluated overall genomic integrity, DNA damage/repair by applying a fluorescence-detected alkaline DNA unwinding assay together with Western blot analyses for phosphorylated H2AX and Q-FISH was applied for investigation of telomeric damage. Our results indicate that hMSC and TERT-immortalized hMSCs can cope with relatively high doses of {gamma}-rays and that overall DNA repair is similar in the two cell lines. The telomeres were extensively destroyed after irradiation in both cell types suggesting that telomere caps are especially sensitive to radiation. The TERT-immortalized hMSCs showed higher stability at telomeric regions than primary hMSCs indicating that cells with long telomeres and high telomerase activity have the advantage of re-establishing the telomeric caps.

  13. Thermodynamic Stability of Ice II and Its Hydrogen-Disordered Counterpart: Role of Zero-Point Energy.

    PubMed

    Nakamura, Tatsuya; Matsumoto, Masakazu; Yagasaki, Takuma; Tanaka, Hideki

    2016-03-01

    We investigate why no hydrogen-disordered form of ice II has been found in nature despite the fact that most of hydrogen-ordered ices have hydrogen-disordered counterparts. The thermodynamic stability of a set of hydrogen-ordered ice II variants relative to ice II is evaluated theoretically. It is found that ice II is more stable than the disordered variants so generated as to satisfy the simple ice rule due to the lower zero-point energy as well as the pair interaction energy. The residual entropy of the disordered ice II phase gradually compensates the unfavorable free energy with increasing temperature. The crossover, however, occurs at a high temperature well above the melting point of ice III. Consequently, the hydrogen-disordered phase does not exist in nature. The thermodynamic stability of partially hydrogen-disordered ices is also scrutinized by examining the free-energy components of several variants obtained by systematic inversion of OH directions in ice II. The potential energy of one variant is lower than that of the ice II structure, but its Gibbs free energy is slightly higher than that of ice II due to the zero-point energy. The slight difference in the thermodynamic stability leaves the possibility of the partial hydrogen-disorder in real ice II. PMID:26595233

  14. GW150914: First Search for the Electromagnetic Counterpart of a Gravitational-wave Event by the TOROS Collaboration

    NASA Astrophysics Data System (ADS)

    Díaz, Mario C.; Beroiz, Martín; Peñuela, Tania; Macri, Lucas M.; Oelkers, Ryan J.; Yuan, Wenlong; García Lambas, Diego; Cabral, Juan; Colazo, Carlos; Domínguez, Mariano; Sánchez, Bruno; Gurovich, Sebastián; Lares, Marcelo; Schneiter, Matías; Graña, Darío; Renzi, Víctor; Rodriguez, Horacio; Starck, Manuel; Vrech, Rubén; Artola, Rodolfo; Chiavassa Ferreyra, Antonio; Girardini, Carla; Quiñones, Cecilia; Tapia, Luis; Tornatore, Marina; Marshall, Jennifer L.; DePoy, Darren L.; Branchesi, Marica; Brocato, Enzo; Padilla, Nelson; Pereyra, Nicolas A.; Mukherjee, Soma; Benacquista, Matthew; Key, Joey

    2016-09-01

    We present the results of the optical follow-up conducted by the TOROS collaboration of the first gravitational-wave event GW150914. We conducted unfiltered CCD observations (0.35–1 μm) with the 1.5 m telescope at Bosque Alegre starting ∼2.5 days after the alarm. Given our limited field of view (∼100 arcmin2), we targeted 14 nearby galaxies that were observable from the site and were located within the area of higher localization probability. We analyzed the observations using two independent implementations of difference-imaging algorithms, followed by a Random-Forest-based algorithm to discriminate between real and bogus transients. We did not find any bona fide transient event in the surveyed area down to a 5σ limiting magnitude of r = 21.7 mag (AB). Our result is consistent with the LIGO detection of a binary black hole merger, for which no electromagnetic counterparts are expected, and with the expected rates of other astrophysical transients.

  15. Molecular structure and immune-stimulated transcriptional modulation of the first teleostean IFP35 counterpart from rockfish (Sebastes schlegelii).

    PubMed

    Perera, N C N; Godahewa, G I; Nam, Bo-Hye; Lee, Jehee

    2016-09-01

    Interferons (IFNs) and IFN-inducible proteins play numerous physiological roles, particularly in antiviral defense mechanisms of the innate immune response with the presence of pathogens. IFN-induced protein-35 kDa (IFP35) is induced by Type II IFN (IFN-γ); it is a cytoplasmic protein that can be translocated to the nucleus via the stimulation of IFN. In this study, we report the complete molecular characterization of the IFP35 cDNA sequence from the black rockfish in an effort to understand its role in the immune response. The coding sequence of RfIFP35 encoded a putative peptide of 371 amino acids containing two characteristic Nmi/IFP 35 domains (NIDs), which are highly conserved among its counterparts. The protein showed a molecular mass of 42.2 kDa with a theoretical pI of 5.05 and was predicted to be unstable because of its high instability index (49.37). Therefore, the protein-protein interaction is essential for its stability, which may be facilitated by the intrinsically disordered regions in this protein. According to cellular location prediction, the RfIFP35 protein is cytosolic. Phylogenetic analysis showed that RfIFP35 was cladded within the fish counterparts. Tissue distribution profiling revealed a ubiquitous presence of the protein in all examined tissues, with highest expression in the blood followed by the spleen tissues. The expression of RfIFP35 during immune challenge with poly I:C and lipopolysaccharide treatments affirms its putative importance in the first-line host defense system. RfIFN-γ mRNA was significantly expressed at 6 h p.i. in blood and 3 h p.i. in the spleen following treatment with different immune stimulants, and its expression was higher compared to that of RfIFP35 mRNA. Therefore, the modulation patterns of both RfIFP35 and RfIFN-γ suggest that RfIFP35 may be induced by RfIFN-γ. PMID:27514784

  16. Evaluation of antioxidant capacity of 13 plant extracts by three different methods: cluster analyses applied for selection of the natural extracts with higher antioxidant capacity to replace synthetic antioxidant in lamb burgers.

    PubMed

    Fernandes, R P P; Trindade, M A; Tonin, F G; Lima, C G; Pugine, S M P; Munekata, P E S; Lorenzo, J M; de Melo, M P

    2016-01-01

    The aims of this study were: to evaluate the total equivalent antioxidant capacities (TEAC) and phenolic contents of 13 plants extracts; to select the most promising extracts regarding reducing activity using cluster analysis multivariate statistical technique; and to analyse evaluate sensory acceptance of lamb burgers produced with the most promising natural antioxidants replacing sodium erythorbate. Plant extracts were evaluated regarding TEAC by DPPH(•) and FRAP methods, and total phenolics contents by Folin-Ciocalteau assay. The TEAC values ranged from 0.50 to 9.06 g trolox/100 g dry weight (dw) and from 43.6 to 472.32 μmol trolox/g dw for DPPH(•) and FRAP methods, respectively, and the total phenolic contents from 5.98 to 74.01 mg GAE/g dw. Extracts from Origanum vulgare, Melissa officinalis, Origanum majorana L. and Rosmarinus officinalis were grouped as the ones with higher antioxidant capacities by cluster analysis. All burgers produced with each one of these four plant extracts or with sodium erythorbate showed no differences (P > 0.05) regarding consumers' sensory acceptance. In conclusion, it is possible to replace sodium erythorbate in lamb burgers by any of the four natural extracts selected without compromising sensory acceptance of this meat product. PMID:26787964

  17. A common registration-to-publication automated pipeline for nomenclatural acts for higher plants (International Plant Names Index, IPNI), fungi (Index Fungorum, MycoBank) and animals (ZooBank)

    PubMed Central

    Penev, Lyubomir; Paton, Alan; Nicolson, Nicola; Kirk, Paul; Pyle, Richard L.; Whitton, Robert; Georgiev, Teodor; Barker, Christine; Hopkins, Christopher; Robert, Vincent; Biserkov, Jordan; Stoev, Pavel

    2016-01-01

    Abstract Collaborative effort among four lead indexes of taxon names and nomenclatural acts (International Plant Name Index (IPNI), Index Fungorum, MycoBank and ZooBank) and the journals PhytoKeys, MycoKeys and ZooKeys to create an automated, pre-publication, registration workflow, based on a server-to-server, XML request/response model. The registration model for ZooBank uses the TaxPub schema, which is an extension to the Journal Tag Publishing Suite (JATS) of the National Library of Medicine (NLM). The indexing or registration model of IPNI and Index Fungorum will use the Taxonomic Concept Transfer Schema (TCS) as a basic standard for the workflow. Other journals and publishers who intend to implement automated, pre-publication, registration of taxon names and nomenclatural acts can also use the open sample XML formats and links to schemas and relevant information published in the paper. PMID:26877662

  18. A common registration-to-publication automated pipeline for nomenclatural acts for higher plants (International Plant Names Index, IPNI), fungi (Index Fungorum, MycoBank) and animals (ZooBank).

    PubMed

    Penev, Lyubomir; Paton, Alan; Nicolson, Nicola; Kirk, Paul; Pyle, Richard L; Whitton, Robert; Georgiev, Teodor; Barker, Christine; Hopkins, Christopher; Robert, Vincent; Biserkov, Jordan; Stoev, Pavel

    2016-01-01

    Collaborative effort among four lead indexes of taxon names and nomenclatural acts (International Plant Name Index (IPNI), Index Fungorum, MycoBank and ZooBank) and the journals PhytoKeys, MycoKeys and ZooKeys to create an automated, pre-publication, registration workflow, based on a server-to-server, XML request/response model. The registration model for ZooBank uses the TaxPub schema, which is an extension to the Journal Tag Publishing Suite (JATS) of the National Library of Medicine (NLM). The indexing or registration model of IPNI and Index Fungorum will use the Taxonomic Concept Transfer Schema (TCS) as a basic standard for the workflow. Other journals and publishers who intend to implement automated, pre-publication, registration of taxon names and nomenclatural acts can also use the open sample XML formats and links to schemas and relevant information published in the paper. PMID:26877662

  19. Flat-Spectrum Radio Sources as Likely Counterparts of Unidentified INTEGRAL Sources (Research Note)

    NASA Technical Reports Server (NTRS)

    Molina, M.; Landi, R.; Bassani, L.; Malizia, A.; Stephen, J. B.; Bazzano, A.; Bird, A. J.; Gehrels, N.

    2012-01-01

    Many sources in the fourth INTEGRAL/IBIS catalogue are still unidentified since they lack an optical counterpart. An important tool that can help in identifying and classifying these sources is the cross-correlation with radio catalogues, which are very sensitive and positionally accurate. Moreover, the radio properties of a source, such as the spectrum or morphology, could provide further insight into its nature. In particular, flat-spectrum radio sources at high Galactic latitudes are likely to be AGN, possibly associated to a blazar or to the compact core of a radio galaxy. Here we present a small sample of 6 sources extracted from the fourth INTEGRAL/IBIS catalogue that are still unidentified or unclassified, but which are very likely associated with a bright, flat-spectrum radio object. To confirm the association and to study the source X-ray spectral parameters, we performed X-ray follow-up observations with Swift/XRT of all objects. We report in this note the overall results obtained from this search and discuss the nature of each individual INTEGRAL source. We find that 5 of the 6 radio associations are also detected in X-rays; furthermore, in 3 cases they are the only counterpart found. More specifically, IGR J06073-0024 is a flat-spectrum radio quasar at z = 1.08, IGR J14488-4008 is a newly discovered radio galaxy, while IGR J18129-0649 is an AGN of a still unknown type. The nature of two sources (IGR J07225-3810 and IGR J19386-4653) is less well defined, since in both cases we find another X-ray source in the INTEGRAL error circle; nevertheless, the flat-spectrum radio source, likely to be a radio loud AGN, remains a viable and, in fact, a more convincing association in both cases. Only for the last object (IGR J11544-7618) could we not find any convincing counterpart since the radio association is not an X-ray emitter, while the only X-ray source seen in the field is a G star and therefore unlikely to produce the persistent emission seen by INTEGRAL.

  20. VizieR Online Data Catalog: Optical counterparts of X-ray sources in OGLE (Udalski+, 2012)

    NASA Astrophysics Data System (ADS)

    Udalski, A.; Kowalczyk, K.; Soszynski, I.; Poleski, R.; Szymanski, M. K.; Kubiak, M.; Pietrzynski, G.; Kozlowski, S.; Pietrukowicz, P.; Ulaczyk, K.; Skowron, J.; Wyrzykowski, L.

    2012-11-01

    We present a sample of 209 variable objects - very likely optical counterparts to the X-ray sources detected in the direction of the Galactic center by the Galactic Bulge Survey (GBS) carried out with the Chandra satellite. The variable sources were found in the databases of the OGLE long term survey monitoring regularly the Galactic bulge since 1992. The counterpart candidates were searched based on the X-ray source position in the radius of 3.9 arcsec. (2 data files).

  1. A possible WISE blazar counterpart of the faint INTEGRAL active galactic nucleus IGR J02341+0228

    NASA Astrophysics Data System (ADS)

    Massaro, F.; Paggi, A.; D'Abrusco, R.

    2012-05-01

    Following the Swift-XRT identification of the counterpart for the faint INTEGRAL active galactic nucleus IGR J02341+0228, associated with a new extragalactic source: QSO B0231+022 (ATEL #4102), we searched in the Wide-field Infrared Survey Explorer (WISE; Wright et al. 2010 AJ, 140, 1868) catalog at the position of the QSO B0231+022 source for an infrared counterpart.

  2. Acetylcholinesterase immobilization and characterization, and comparison of the activity of the porous silicon-immobilized enzyme with its free counterpart.

    PubMed

    Saleem, Muhammad; Rafiq, Muhammad; Seo, Sung-Yum; Lee, Ki Hwan

    2016-01-01

    A successful prescription is presented for acetylcholinesterase physically adsorbed on to a mesoporous silicon surface, with a promising hydrolytic response towards acetylthiocholine iodide. The catalytic behaviour of the immobilized enzyme was assessed by spectrophotometric bioassay using neostigmine methyl sulfate as a standard acetycholinesterase inhibitor. The surface modification was studied through field emission SEM, Fourier transform IR spectroscopy, energy-dispersive X-ray spectroscopy, cathode luminescence and X-ray photoelectron spectroscopy analysis, photoluminescence measurement and spectrophotometric bioassay. The porous silicon-immobilized enzyme not only yielded greater enzyme stability, but also significantly improved the native photoluminescence at room temperature of the bare porous silicon architecture. The results indicated the promising catalytic behaviour of immobilized enzyme compared with that of its free counterpart, with a greater stability, and that it aided reusability and easy separation from the reaction mixture. The porous silicon-immobilized enzyme was found to retain 50% of its activity, promising thermal stability up to 90°C, reusability for up to three cycles, pH stability over a broad pH of 4-9 and a shelf-life of 44 days, with an optimal hydrolytic response towards acetylthiocholine iodide at variable drug concentrations. On the basis of these findings, it was believed that the porous silicon-immobilized enzyme could be exploited as a reusable biocatalyst and for screening of acetylcholinesterase inhibitors from crude plant extracts and synthesized organic compounds. Moreover, the immobilized enzyme could offer a great deal as a viable biocatalyst in bioprocessing for the chemical and pharmaceutical industries, and bioremediation to enhance productivity and robustness. PMID:26839417

  3. Acetylcholinesterase immobilization and characterization, and comparison of the activity of the porous silicon-immobilized enzyme with its free counterpart

    PubMed Central

    Saleem, Muhammad; Rafiq, Muhammad; Seo, Sung-Yum; Lee, Ki Hwan

    2016-01-01

    A successful prescription is presented for acetylcholinesterase physically adsorbed on to a mesoporous silicon surface, with a promising hydrolytic response towards acetylthiocholine iodide. The catalytic behaviour of the immobilized enzyme was assessed by spectrophotometric bioassay using neostigmine methyl sulfate as a standard acetycholinesterase inhibitor. The surface modification was studied through field emission SEM, Fourier transform IR spectroscopy, energy-dispersive X-ray spectroscopy, cathode luminescence and X-ray photoelectron spectroscopy analysis, photoluminescence measurement and spectrophotometric bioassay. The porous silicon-immobilized enzyme not only yielded greater enzyme stability, but also significantly improved the native photoluminescence at room temperature of the bare porous silicon architecture. The results indicated the promising catalytic behaviour of immobilized enzyme compared with that of its free counterpart, with a greater stability, and that it aided reusability and easy separation from the reaction mixture. The porous silicon-immobilized enzyme was found to retain 50% of its activity, promising thermal stability up to 90°C, reusability for up to three cycles, pH stability over a broad pH of 4–9 and a shelf-life of 44 days, with an optimal hydrolytic response towards acetylthiocholine iodide at variable drug concentrations. On the basis of these findings, it was believed that the porous silicon-immobilized enzyme could be exploited as a reusable biocatalyst and for screening of acetylcholinesterase inhibitors from crude plant extracts and synthesized organic compounds. Moreover, the immobilized enzyme could offer a great deal as a viable biocatalyst in bioprocessing for the chemical and pharmaceutical industries, and bioremediation to enhance productivity and robustness. PMID:26839417

  4. [Plant hormones, plant growth regulators].

    PubMed

    Végvári, György; Vidéki, Edina

    2014-06-29

    Plants seem to be rather defenceless, they are unable to do motion, have no nervous system or immune system unlike animals. Besides this, plants do have hormones, though these substances are produced not in glands. In view of their complexity they lagged behind animals, however, plant organisms show large scale integration in their structure and function. In higher plants, such as in animals, the intercellular communication is fulfilled through chemical messengers. These specific compounds in plants are called phytohormones, or in a wide sense, bioregulators. Even a small quantity of these endogenous organic compounds are able to regulate the operation, growth and development of higher plants, and keep the connection between cells, tissues and synergy between organs. Since they do not have nervous and immume systems, phytohormones play essential role in plants' life. PMID:24954142

  5. Strategic Wholesale Pricing for an Incumbent Supplier Facing with a Competitive Counterpart

    PubMed Central

    Sun, Jianwu

    2014-01-01

    We introduce a wholesale pricing strategy for an incumbent supplier facing with a competitive counterpart. We propose a profit function which considers both the present loss and future loss from a wholesale price and then study the optimal wholesale prices for different objectives about this profit function for the incumbent supplier. First, we achieve an optimal wholesale price for the incumbent supplier to maximize his expected profit. Then, to reduce the risk originating from the fluctuation in the competitive supplier's wholesale price, we integrate the conditional value-at-risk (CVaR) measure in financial risk management into this study and derive an optimal wholesale price to maximize CVaR about profit for the incumbent supplier. Besides, the properties of the two optimal wholesale prices are discussed. Finally, some management insights are suggested for the incumbent supplier in a competitive setting. PMID:25614891

  6. Cygnus X-3 Little Friend's Counterpart, the Distance to Cygnus X-3 and Jets (Oh My!)

    NASA Astrophysics Data System (ADS)

    McCollough, Michael L.; Dunham, Michael M.; Corrales, Lia

    2016-04-01

    Chandra observations have revealed a feature within 16" of Cygnus X-3 which varied in phase with Cygnus X-3. This feature was shown to be a Bok globule which is along the line of sight to Cygnus X-3. We report onobservations made with Submillimeter Array (SMA) to search for molecular emission from this globule, also known as Cygnus X-3's "little friend." We have found a counterpart in both 12CO and 13CO emission. From the velocity shift of the molecular lines we are able determine a kinematic distance to the little friend and in turn a distance to Cygnus X-3. The uncertainties in this distance estimate to Cygnus X-3 are less than 10%. An additional unexpected discovery was that Cygnus X-3 is not the only source to have jets!

  7. Comparison of occupational hearing losses among military engineers and their civilian counterparts

    SciTech Connect

    Fletcher, J.L.; Chandler, D.W.

    1983-10-01

    A previous study examined group hearing loss of 209 U.S.Army engineers by comparing current with reference audiograms. The sample was categorized by military occupation specialty, age, and time on job. The present study reports comparable data for 187 civilian engineers on the same Army post exposed to essentially the same noise. These had less hearing loss than their military counterparts. Some reasons are suggested, such as attrition of the civilian workforce because of hearing problems, and a likely greater exposure of the military engineers to noises not job-related. Age was less important than time on the job. Both groups, however, exhibited significantly lower hearing levels than the industrial population of Glorig et al at the 1954 Wisconsin State Fair, possibly because both military and civilian personnel at this Army post had been for some years in an aggressive hearing conservation program.

  8. Medicare Prescription Drug Plan Enrollees Report Less Positive Experiences Than Their Medicare Advantage Counterparts.

    PubMed

    Elliott, Marc N; Landon, Bruce E; Zaslavsky, Alan M; Edwards, Carol; Orr, Nathan; Beckett, Megan K; Mallett, Joshua; Cleary, Paul D

    2016-03-01

    Since 2006, Medicare beneficiaries have been able to obtain prescription drug coverage through standalone prescription drug plans or their Medicare Advantage (MA) health plan, options exercised in 2015 by 72 percent of beneficiaries. Using data from community-dwelling Medicare beneficiaries older than age sixty-four in 700 plans surveyed from 2007 to 2014, we compared beneficiaries' assessments of Medicare prescription drug coverage when provided by standalone plans or integrated into an MA plan. Beneficiaries in standalone plans consistently reported less positive experiences with prescription drug plans (ease of getting medications, getting coverage information, and getting cost information) than their MA counterparts. Because MA plans are responsible for overall health care costs, they might have more integrated systems and greater incentives than standalone prescription drug plans to provide enrollees medications and information effectively, including, since 2010, quality bonus payments to these MA plans under provisions of the Affordable Care Act. PMID:26953300

  9. The Counterparts of the Luminous, Bursting X-ray Sources in Globular Clusters-LTSA98

    NASA Technical Reports Server (NTRS)

    Anderson, Scott F.

    2003-01-01

    Under the fifth year of the LTSA, we have extended our HST and Chandra work to a number of additional globular clusters. The remarkable sensitivity and positional accuracy of the Chandra observations are enabling us to maximally exploit HST for UV/optical identifications for X-ray binaries in the cores of multiple globular clusters. The dozens of lower-luminosity X-ray sources in each globular cluster deeply examined thus far have moved us firmly into the era of studies which encompass populations of close; the large range of cluster properties we are studying have, for the first tine, established a firm empirical confirmation of the (long-suspected theoretically) high importance that close binaries play in the dynamical stability and evolution of globular clusters. The LTSA support has been a cornerstone of our success over the past 5 years in studies of globular cluster X-ray sources and their counterparts.

  10. A differential diagnosis of inherited endocrine tumors and their tumor counterparts

    PubMed Central

    Toledo, Sergio P. A.; Lourenço, Delmar M.; Toledo, Rodrigo A.

    2013-01-01

    Inherited endocrine tumors have been increasingly recognized in clinical practice, although some difficulties still exist in differentiating these conditions from their sporadic endocrine tumor counterparts. Here, we list the 12 main topics that could add helpful information and clues for performing an early differential diagnosis to distinguish between these conditions. The early diagnosis of patients with inherited endocrine tumors may be performed either clinically or by mutation analysis in at-risk individuals. Early detection usually has a large impact in tumor management, allowing preventive clinical or surgical therapy in most cases. Advice for the clinical and surgical management of inherited endocrine tumors is also discussed. In addition, recent clinical and genetic advances for 17 different forms of inherited endocrine tumors are briefly reviewed. PMID:23917672

  11. A Likely Millisecond Pulsar Binary Counterpart for Fermi Source 2FGL J2039.6-5620

    NASA Astrophysics Data System (ADS)

    Romani, Roger W.

    2015-10-01

    We have identified an optical/X-ray binary with an orbital period of Pb = 5.47 hr as the likely counterpart of the Fermi source 2FGL J2039.6-5620. GROND, SOAR, and DES observations provide an accurate orbital period and allow us to compare to the light curve of an archival XMM exposure. Like many short-period optical/X-ray binaries associated with Large Area Telescope sources, this may be an interacting (black widow/redback) millisecond pulsar binary. The X-ray light curve is consistent with the emission associated with an intrabinary shock. The optical light curve shows evidence of companion heating, but has a peculiar asymmetric double peak. The nature of this optical structure is not yet clear; additional optical studies and, in particular, detection of an orbital modulation in a γ-ray pulsar are needed to elucidate the nature of this peculiar source.

  12. Rapid Search for a Near-Infrared Counterpart of GRB 960924

    NASA Technical Reports Server (NTRS)

    Klose, S.; Stecklum, B.; Eisloffel, J.; Nassir, M. A.; Hurley, K.; Kouveliotou, C.; Meegan, C. A.; Fishman, G. J.; Barthelmy, S. D.; Cline, T. L.

    1998-01-01

    We report the results of a rapid search for a near-infrared counterpart of the very strong gamma-ray burst 960924. The survey was performed in JHK-prime only 3.5 days after the burst. It was centered at the most probable burster position and covers about 1/3 of the BACODINE/IPN/Huntsville error box represented by the intersection of the 1-sigma, BATSE error circle and the 3-sigma, IPN annulus. Second epoch observations were carried out in the near-infrared about 100 days and 500 days after the burst. No Near Infrared (NIR) transient source was detected within the surveyed IPN annulus to magnitude limits J is approximately 17.5 and K is approximately 15-5.

  13. Quiescent X-ray/optical counterparts of the black hole transient H 1705-250

    NASA Astrophysics Data System (ADS)

    Yang, Y. J.; Kong, A. K. H.; Russell, D. M.; Lewis, F.; Wijnands, R.

    2012-12-01

    We report the result of a new Chandra observation of the black hole X-ray transient H 1705-250 in quiescence. H 1705-250 was barely detected in the new ˜50 ks Chandra observation. With five detected counts, we estimate the source quiescent luminosity to be LX ˜ 9.1 × 1030 erg s-1 in the 0.5-10 keV band (adopting a distance of 8.6 kpc). This value is in line with the quiescent luminosities found among other black hole X-ray binaries with similar orbital periods. By using images taken with the Faulkes Telescope North, we derive a refined position of H 1705-250. We also present the long-term light curve of the optical counterpart from 2006 to 2012, and show evidence for variability in quiescence.

  14. Turbulent flow over wetted and non-wetted superhydrophobic counterparts with random structure

    NASA Astrophysics Data System (ADS)

    Vajdi Hokmabad, B.; Ghaemi, S.

    2016-01-01

    The turbulent structure of a channel flow over a non-wetted superhydrophobic (SHO) surface is experimentally investigated at Re = 9600 (based on channel width) at the region of y+ > 10 within the buffer and logarithmic layers. The SHO surface has a random pattern produced by spray coating and is compared with a wetted counterpart and also a smooth surface. Two planar particle image velocimetry measurements are carried out in the streamwise/spanwise and streamwise/wall-normal planes. The vector fields are obtained from both ensemble averaging and individual cross-correlations of double-frame images. The results showed a small increase (˜5%) of the mean velocity profile at y+ = 10 over the non-wetted surface in comparison with the wetted and the smooth surfaces. Up to 15% reduction of normal and shear Reynolds stresses is observed in the inner layer over the non-wetted SHO surface. The wetted SHO counterpart demonstrates no effect on the mean velocity and Reynolds stresses in comparison with the smooth surface. The result confirms the comment of Gad-el-Hak ["Experimental study of skin friction drag reduction on superhydrophobic flat plates in high Reynolds number boundary layer flow," Phys. Fluids 25, 025103 (2013)] that the wetted SHO is hydrodynamically smooth if the surface pores are smaller than the viscous sublayer thickness. A noticeable suppression of the sweep and ejection events, increase of the spanwise spacing of the low and high speed streaks, and attenuation of vortical structures are observed over the non-wetted SHO. These indicate attenuation of the turbulence regeneration cycle due to the slip boundary condition over the non-wetted SHO surfaces with random texture.

  15. A search for optical counterparts of gamma-ray bursts. Final report

    SciTech Connect

    Park, Hye-Sook

    1995-03-09

    Gamma Ray Bursts (GRBS) are mysterious flashes of gamma rays lasting several tens to hundreds of seconds that occur approximately once per day. NASA launched the orbiting Compton Gamma Ray Observatory to study GRBs and other gamma ray phenomena. CGRO carries the Burst and Transient Experiment (BATSE) specifically to study GRBS. Although BATSE has collected data on over 600 GRBS, and confirmed that GRBs are localized, high intensity point sources of MeV gamma rays distributed isotropically in the sky, the nature and origin of GRBs remains a fundamental problem in astrophysics. BATSE`s 8 gamma ray sensors located on the comers of the box shaped CGRO can detect the onset of GRBs and record their intensity and energy spectra as a function of time. The position of the burst on the sky can be determined to < {plus_minus}10{degrees} from the BATSE data stream. This position resolution is not sufficient to point a large, optical telescope at the exact position of a GRB which would determine its origin by associating it with a star. Because of their brief duration it is not known if GRBs are accompanied by visible radiation. Their seemingly large energy output suggests thatthis should be. Simply scaling the ratio of visible to gamma ray intensities of the Crab Nebula to the GRB output suggests that GRBs ought to be accompanied by visible flashes of magnitude 10 or so. A few photographs of areas containing a burst location that were coincidentally taken during the burst yield lower limits on visible output of magnitude 4. The detection of visible light during the GRB would provide information on burst physics, provide improved pointing coordinates for precise examination of the field by large telescope and provide the justification for larger dedicated optical counterpart instruments. The purpose of this experiment is to detect or set lower limits on optical counterpart radiation simultaneously accompanying the gamma rays from

  16. Variability of Optical Counterparts to X-ray Selected Sources in the Galactic Bulge Survey

    NASA Astrophysics Data System (ADS)

    Johnson, Christopher; Hynes, Robert I.; Jonker, Peter; Torres, Manuel; Maccarone, Thomas J.; Britt, Christopher; Steeghs, Danny; Galactic Bulge Survey Collaboration

    2016-01-01

    The Galactic Bulge Survey (GBS) is a wide-field, multi-wavelength survey of new X-ray sources in the Galactic Bulge detected with the Chandra X-ray Observatory. The goals of the GBS are to test binary population models by uncovering quiescent Low-Mass X-Ray Binaries (LMXB), and to identify suitable systems for follow-up mass determination using multi-wavelength observations. This follow-up is essential to better determine black hole and neutron star mass distributions. We present preliminary results from the southernmost portion of the GBS positioned 1.5-2.0 degrees below the Galactic Center which contains 424 unique X-ray sources. The optical photometry presented here were acquired using the DECam imager and the previous Mosaic-II imager on the 4m Blanco telescope at Cerro-Tololo Inter-American Observatory (CTIO). We combine photometry with optical spectroscopy from several different telescopes to help characterize the detected X-ray sources. To accomplish this goal, we analyze the light curve morphology and the spectroscopic features of the optical counterparts to classify these binary systems. I will describe the technique for determining the correct optical counterpart within the error circle using image subtraction and report on the statistics of the sample. I will then summarize the candidate LMXBs we have identified so far and highlight other interesting sources. This work was supported by the National Science Foundation under Grant No. AST-0908789 and by NASA through Chandra Award Number AR3-14002X issued by the Chandra X-ray Observatory Center, which is operated by the Smithsonian Astrophysical Observatory for and on behalf of the National Aeronautics Space Administration under contract NAS8-03060. We also acknowledge support from a Graduate Student Research Award administered by the Louisiana Space Grant Consortium (LaSPACE).

  17. Direct band gaps in group IV-VI monolayer materials: Binary counterparts of phosphorene

    NASA Astrophysics Data System (ADS)

    Kamal, C.; Chakrabarti, Aparna; Ezawa, Motohiko

    2016-03-01

    We perform systematic investigation on the geometric, energetic, and electronic properties of group IV-VI binary monolayers (XY ), which are the counterparts of phosphorene, by employing density functional theory based electronic structure calculations. For this purpose, we choose the binary systems X Y consisting of equal numbers of group IV (X = C, Si, Ge, Sn) and group VI elements (Y = O, S, Se, Te) in three geometrical configurations, the puckered, buckled and planar structures. The results of binding energy calculations show that all the binary systems studied are energetically stable. It is observed that, the puckered structure, similar to that of phosphorene, is the energetically most stable geometric configuration. Moreover, the binding energies of buckled configuration are very close to those of the puckered configuration. Our results of electronic band structure predict that puckered SiO and CSe are direct band semiconductors with gaps of 1.449 and 0.905 eV, respectively. Band structure of CSe closely resembles that of phosphorene. Remaining group IV-VI binary monolayers in the puckered configuration and all the buckled monolayers are also semiconductors, but with indirect band gaps. Importantly, we find that the difference between indirect and direct band gaps is very small for many puckered monolayers. Thus there is a possibility of making these systems undergo transition from indirect to direct band gap semiconducting state by a suitable external influence. Indeed, we show in the present work that seven binary monolayers, namely, SnS, SiSe, GeSe, SnSe, SiTe, GeTe, and SnTe become direct band gap semiconductors when they are subjected to a small mechanical strain (≤3 % ). This makes nine out of sixteen binary monolayers studied in the present work direct band gap semiconductors. Thus there is a possibility of utilizing these binary counterparts of phosphorene in future light-emitting diodes and solar cells.

  18. A Detailed Study of Contamination in Deep Rapid Searches for Gravitational Wave Optical Counterparts

    NASA Astrophysics Data System (ADS)

    Cowperthwaite, Philip; Berger, Edo; Chornock, Ryan; Fong, Wen-fai

    2015-01-01

    The first direct detection of gravitational waves (GW) by the Advanced LIGO/VIRGO (aLIGO/VIRGO) collaboration is expected to occur within the next few years. In order to maximize the science gains from such a detection it is essential that we identify an electromagnetic counterpart. One of the most promising counterparts is the so-called 'kilonovae,' a fast-evolving (t ~ days) and faint (z ~ 24 AB mag) optical transient powered by the radioactive decay of r-process elements generated in the merger. However, the poor initial localization of aLIGO/VIRGO (~ 100 sq. deg.) demand the use of wide-field telescopes. Furthermore, the cadences and depths used by current and future wide-field optical surveys (e.g. PTF/ZTF, PANStarrs, LSST) are sub-optimal for kilonovae detection. We present our attempts to tackle these issues by investigating the theoretical and practical issues associated with optical follow-up of an aLIGO/VIRGO GW event. This includes a systematic study of the potential contaminant population and their impact on kilonovae detectability in simulated observations. We show that kilonovae can remain separated from contaminants by the virtue of their red colors (i - z > 0.5) and short timescales. This theoretical analysis will be tested against observations obtained by the DECam wide-field imager on the CTIO Blanco 4m telescope. These data attempt to simulate the wide area coverage (~ 70 sq. deg.) and rapid cadence (two visits per night in i,z) necessary for targeted GW follow-up and will provide an excellent test bed for understanding the practical issues associated with this endeavor. This work is supported in part by the NSF GRFP grant DGE1144152.

  19. VizieR Online Data Catalog: ECDFS sources optical/IR counterparts (Bonzini+, 2013)

    NASA Astrophysics Data System (ADS)

    Bonzini, M.; Padovani, P.; Mainieri, V.; Kellermann, K. I.; Miller, N.; Rosati, P.; Tozzi, P.; Vattakunnel, S.

    2015-10-01

    We consider a sample of 883 radio sources detected at 1.4GHz in a deep Very Large Array (VLA) survey of the Extended Chandra Deep Field-South (E-CDFS) that reaches a best rms sensitivity of 6uJy. We used deep Spitzer InfraRed Array Camera (IRAC) and Multiband Imaging Photometer for Spitzer (MIPS) data. The IRAC data were obtained as part of the Spitzer IRAC/MUSYC Public Legacy Survey in the Extended CDF-South (SIMPLE) survey (Damen et al., 2011ApJ...727....1D, Cat. J/ApJ/727/1). It covers an area of about 1600 arcmin2 centred on the E-CDFS. The typical 5σ flux density limits are 1.1, 1.3, 6.3 and 7.6uJy at 3.6, 4.5, 5.8 and 8.0um, respectively. We also use MIPS 24um data from the Far-Infrared Deep Extragalactic Legacy (FIDEL) survey (Dickinson & FIDEL Team, 2007AAS...211.5216D). The E-CDFS has been mapped in the X-ray band by Chandra. A total of 129 radio sources have a counterpart in the 4 Ms observations of the CDFS presented in Xue et al. (2011ApJS..195...10X, Cat. J/ApJS/195/10) and another 99 in the main E-CDFS catalogue by Lehmer et al. (2005ApJS..161...21L, Cat. J/ApJS/161/21) obtained with shallower (250ks) observations in each of four pointings. The list of the X-ray counterparts of the radio sources is given in Bonzini et al. (2012ApJS..203...15B, Cat. J/ApJS/203/15). (1 data file).

  20. A Search for an Optical Counterpart to the Gravitational-wave Event GW151226

    NASA Astrophysics Data System (ADS)

    Smartt, S. J.; Chambers, K. C.; Smith, K. W.; Huber, M. E.; Young, D. R.; Chen, T.-W.; Inserra, C.; Wright, D. E.; Coughlin, M.; Denneau, L.; Flewelling, H.; Heinze, A.; Jerkstrand, A.; Magnier, E. A.; Maguire, K.; Mueller, B.; Rest, A.; Sherstyuk, A.; Stalder, B.; Schultz, A. S. B.; Stubbs, C. W.; Tonry, J.; Waters, C.; Wainscoat, R. J.; Della Valle, M.; Dennefeld, M.; Dimitriadis, G.; Firth, R. E.; Fraser, M.; Frohmaier, C.; Gal-Yam, A.; Harmanen, J.; Kankare, E.; Kotak, R.; Kromer, M.; Mandel, I.; Sollerman, J.; Gibson, B.; Primak, N.; Willman, M.

    2016-08-01

    We present a search for an electromagnetic counterpart of the gravitational-wave source GW151226. Using the Pan-STARRS1 telescope we mapped out 290 square degrees in the optical i P1 filter, starting 11.5 hr after the LIGO information release and lasting for an additional 28 days. The first observations started 49.5 hr after the time of the GW151226 detection. We typically reached sensitivity limits of i P1 = 20.3–20.8 and covered 26.5% of the LIGO probability skymap. We supplemented this with ATLAS survey data, reaching 31% of the probability region to shallower depths of m ≃ 19. We found 49 extragalactic transients (that are not obviously active galactic nuclei), including a faint transient in a galaxy at 7 Mpc (a luminous blue variable outburst) plus a rapidly decaying M-dwarf flare. Spectral classification of 20 other transient events showed them all to be supernovae. We found an unusual transient, PS15dpn, with an explosion date temporally coincident with GW151226, that evolved into a type Ibn supernova. The redshift of the transient is secure at z = 0.1747 ± 0.0001 and we find it unlikely to be linked, since the luminosity distance has a negligible probability of being consistent with that of GW151226. In the 290 square degrees surveyed we therefore do not find a likely counterpart. However we show that our survey strategy would be sensitive to NS–NS mergers producing kilonovae at D L ≲ 100 Mpc, which is promising for future LIGO/Virgo searches.