WorldWideScience

Sample records for higher plant glycosyltransferases

  1. Plant cell wall glycosyltransferases: High-throughput recombinant expression screening and general requirements for these challenging enzymes

    DEFF Research Database (Denmark)

    Welner, Ditte Hededam; Shin, David; Tomaleri, Giovani P.

    2017-01-01

    Molecular characterization of plant cell wall glycosyltransferases is a critical step towards understanding the biosynthesis of the complex plant cell wall, and ultimately for efficient engineering of biofuel and agricultural crops. The majority of these enzymes have proven very difficult to obta...

  2. A Complementary Bioinformatics Approach to Identify Potential Plant Cell Wall Glycosyltransferase-Encoding Genes

    DEFF Research Database (Denmark)

    Egelund, Jack; Skjøt, Michael; Geshi, Naomi

    2004-01-01

    Plant cell wall (CW) synthesizing enzymes can be divided into the glycan (i.e. cellulose and callose) synthases, which are multimembrane spanning proteins located at the plasma membrane, and the glycosyltransferases (GTs), which are Golgi localized single membrane spanning proteins, believed....... Although much is known with regard to composition and fine structures of the plant CW, only a handful of CW biosynthetic GT genes-all classified in the CAZy system-have been characterized. In an effort to identify CW GTs that have not yet been classified in the CAZy database, a simple bioinformatics...... approach was adopted. First, the entire Arabidopsis proteome was run through the Transmembrane Hidden Markov Model 2.0 server and proteins containing one or, more rarely, two transmembrane domains within the N-terminal 150 amino acids were collected. Second, these sequences were submitted...

  3. A conserved fungal glycosyltransferase facilitates pathogenesis of plants by enabling hyphal growth on solid surfaces.

    Directory of Open Access Journals (Sweden)

    Robert King

    2017-10-01

    Full Text Available Pathogenic fungi must extend filamentous hyphae across solid surfaces to cause diseases of plants. However, the full inventory of genes which support this is incomplete and many may be currently concealed due to their essentiality for the hyphal growth form. During a random T-DNA mutagenesis screen performed on the pleomorphic wheat (Triticum aestivum pathogen Zymoseptoria tritici, we acquired a mutant unable to extend hyphae specifically when on solid surfaces. In contrast "yeast-like" growth, and all other growth forms, were unaffected. The inability to extend surface hyphae resulted in a complete loss of virulence on plants. The affected gene encoded a predicted type 2 glycosyltransferase (ZtGT2. Analysis of >800 genomes from taxonomically diverse fungi highlighted a generally widespread, but discontinuous, distribution of ZtGT2 orthologues, and a complete absence of any similar proteins in non-filamentous ascomycete yeasts. Deletion mutants of the ZtGT2 orthologue in the taxonomically un-related fungus Fusarium graminearum were also severely impaired in hyphal growth and non-pathogenic on wheat ears. ZtGT2 expression increased during filamentous growth and electron microscopy on deletion mutants (ΔZtGT2 suggested the protein functions to maintain the outermost surface of the fungal cell wall. Despite this, adhesion to leaf surfaces was unaffected in ΔZtGT2 mutants and global RNAseq-based gene expression profiling highlighted that surface-sensing and protein secretion was also largely unaffected. However, ΔZtGT2 mutants constitutively overexpressed several transmembrane and secreted proteins, including an important LysM-domain chitin-binding virulence effector, Zt3LysM. ZtGT2 likely functions in the synthesis of a currently unknown, potentially minor but widespread, extracellular or outer cell wall polysaccharide which plays a key role in facilitating many interactions between plants and fungi by enabling hyphal growth on solid matrices.

  4. A conserved fungal glycosyltransferase facilitates pathogenesis of plants by enabling hyphal growth on solid surfaces

    Science.gov (United States)

    Plummer, Amy; Halsey, Kirstie; Lovegrove, Alison; Hammond-Kosack, Kim

    2017-01-01

    Pathogenic fungi must extend filamentous hyphae across solid surfaces to cause diseases of plants. However, the full inventory of genes which support this is incomplete and many may be currently concealed due to their essentiality for the hyphal growth form. During a random T-DNA mutagenesis screen performed on the pleomorphic wheat (Triticum aestivum) pathogen Zymoseptoria tritici, we acquired a mutant unable to extend hyphae specifically when on solid surfaces. In contrast “yeast-like” growth, and all other growth forms, were unaffected. The inability to extend surface hyphae resulted in a complete loss of virulence on plants. The affected gene encoded a predicted type 2 glycosyltransferase (ZtGT2). Analysis of >800 genomes from taxonomically diverse fungi highlighted a generally widespread, but discontinuous, distribution of ZtGT2 orthologues, and a complete absence of any similar proteins in non-filamentous ascomycete yeasts. Deletion mutants of the ZtGT2 orthologue in the taxonomically un-related fungus Fusarium graminearum were also severely impaired in hyphal growth and non-pathogenic on wheat ears. ZtGT2 expression increased during filamentous growth and electron microscopy on deletion mutants (ΔZtGT2) suggested the protein functions to maintain the outermost surface of the fungal cell wall. Despite this, adhesion to leaf surfaces was unaffected in ΔZtGT2 mutants and global RNAseq-based gene expression profiling highlighted that surface-sensing and protein secretion was also largely unaffected. However, ΔZtGT2 mutants constitutively overexpressed several transmembrane and secreted proteins, including an important LysM-domain chitin-binding virulence effector, Zt3LysM. ZtGT2 likely functions in the synthesis of a currently unknown, potentially minor but widespread, extracellular or outer cell wall polysaccharide which plays a key role in facilitating many interactions between plants and fungi by enabling hyphal growth on solid matrices. PMID:29020037

  5. Assay and heterologous expression in Pichia pastoris of plant cell wall type-II membrane anchored glycosyltransferases

    DEFF Research Database (Denmark)

    Petersen, Bent; Egelund, Jack; Damager, Iben

    2009-01-01

    .011 to 0.013 U (1 U = 1 nmol conversion of substrate * min(-1) * microl medium(-1)) similar to those of RGXT1 and RGXT2 expressed in Baculovirus transfected insect Sf9 cells. In summary, the data presented suggest that Pichia is an attractive host candidate for expression of plant glycosyltransferases.......Two Arabidopsis xylosyltransferases, designated RGXT1 and RGXT2, were recently expressed in Baculovirus transfected insect cells and by use of the free sugar assay shown to catalyse transfer of D-xylose from UDP-alpha-D-xylose to L-fucose and derivatives hereof. We have now examined expression...

  6. A genome-wide phylogenetic reconstruction of family 1 UDP-glycosyltransferases revealed the expansion of the family during the adaptation of plants to life on land.

    Science.gov (United States)

    Caputi, Lorenzo; Malnoy, Mickael; Goremykin, Vadim; Nikiforova, Svetlana; Martens, Stefan

    2012-03-01

    For almost a decade, our knowledge on the organisation of the family 1 UDP-glycosyltransferases (UGTs) has been limited to the model plant A. thaliana. The availability of other plant genomes represents an opportunity to obtain a broader view of the family in terms of evolution and organisation. Family 1 UGTs are known to glycosylate several classes of plant secondary metabolites. A phylogeny reconstruction study was performed to get an insight into the evolution of this multigene family during the adaptation of plants to life on land. The organisation of the UGTs in the different organisms was also investigated. More than 1500 putative UGTs were identified in 12 fully sequenced and assembled plant genomes based on the highly conserved PSPG motif. Analyses by maximum likelihood (ML) method were performed to reconstruct the phylogenetic relationships existing between the sequences. The results of this study clearly show that the UGT family expanded during the transition from algae to vascular plants and that in higher plants the clustering of UGTs into phylogenetic groups appears to be conserved, although gene loss and gene gain events seem to have occurred in certain lineages. Interestingly, two new phylogenetic groups, named O and P, that are not present in A. thaliana were discovered. © 2011 The Authors. The Plant Journal © 2011 Blackwell Publishing Ltd.

  7. Radiosensitivity of higher plants

    International Nuclear Information System (INIS)

    Feng Zhijie

    1992-11-01

    The general views on radiosensitivity of higher plants have been introduced from published references. The radiosensitivity varies with species, varieties and organs or tissues. The main factors of determining the radiosensitivity in different species are nucleus volume, chromosome volume, DNA content and endogenous compounds. The self-repair ability of DNA damage and chemical group of biological molecules, such as -SH thiohydroxy of proteins, are main factors to determine the radiosensitivity in different varieties. The moisture, oxygen, temperature radiosensitizer and protector are important external factors for radiosensitivity. Both the multiple target model and Chadwick-Leenhouts model are ideal mathematical models for describing the radiosensitivity of higher plants and the latter has more clear significance in biology

  8. Heterologous expression of plant cell wall glycosyltransferases in Pichia, pea and tobacco

    DEFF Research Database (Denmark)

    Petersen, Bent Larsen; Damager, Iben; Faber, Kirsten

    Cell). In the present study, Flag-tagged (MDYKDDDD) RGXT2 was expressed in Pichia pastoris as secreted soluble protein, in pea (using the Pea early browning virus as expression vector) as soluble intra-cellular protein and in tobacco as full length membrane bound protein. The amount of expressed...... to participate in plant CW biosynthesis, has been achieved in only a few cases. We have previously reported the characterisation of two highly homologous plant-specific membrane-bound GTs, which when expressed as secreted tagged soluble proteins in the baculo virus system, catalysed the transfer of xylose from...... protein was estimated using anti Flag Ab and corresponding activity monitored. Pros and cons of using the various expression systems are discussed....

  9. Arabinogalactan glycosyltransferases target to a unique subcellular compartment that may function in unconventional secretion in plants

    DEFF Research Database (Denmark)

    Poulsen, Christian Peter; Dilokpimol, Adiphol; Mouille, Grégory

    2014-01-01

    -glycosylation enzymes rarely colocalized (3-18%), implicating a role of the small compartments in a part of arabinogalactan (O-glycan) biosynthesis rather than N-glycan processing. The dual localization of AtGALT31A was also observed for fluorescently tagged AtGALT31A stably expressed in an Arabidopsis atgalt31a mutant...... colocalized with neither SYP61 (syntaxin of plants 61), a marker for trans-Golgi network (TGN), nor FM4-64-stained endosomes. However, 41% colocalized with EXO70E2 (Arabidopsis thaliana exocyst protein Exo70 homolog 2), a marker for exocyst-positive organelles, and least affected by Brefeldin A and Wortmannin....... Taken together, AtGALT31A localized to small compartments that are distinct from the Golgi apparatus, the SYP61-localized TGN, FM4-64-stained endosomes and Wortmannin-vacuolated prevacuolar compartments, but may be part of an unconventional protein secretory pathway represented by EXO70E2 in plants....

  10. Cellulose biosynthesis in higher plants

    Directory of Open Access Journals (Sweden)

    Krystyna Kudlicka

    2014-01-01

    Full Text Available Knowledge of the control and regulation of cellulose synthesis is fundamental to an understanding of plant development since cellulose is the primary structural component of plant cell walls. In vivo, the polymerization step requires a coordinated transport of substrates across membranes and relies on delicate orientations of the membrane-associated synthase complexes. Little is known about the properties of the enzyme complexes, and many questions about the biosynthesis of cell wall components at the cell surface still remain unanswered. Attempts to purify cellulose synthase from higher plants have not been successful because of the liability of enzymes upon isolation and lack of reliable in vitro assays. Membrane preparations from higher plant cells incorporate UDP-glucose into a glucan polymer, but this invariably turns out to be predominantly β -1,3-linked rather than β -1,4-linked glucans. Various hypotheses have been advanced to explain this phenomenon. One idea is that callose and cellulose-synthase systems are the same, but cell disruption activates callose synthesis preferentially. A second concept suggests that a regulatory protein as a part of the cellulose-synthase complex is rapidly degraded upon cell disruption. With new methods of enzyme isolation and analysis of the in vitro product, recent advances have been made in the isolation of an active synthase from the plasma membrane whereby cellulose synthase was separated from callose synthase.

  11. Chromosomal replicons of higher plants

    International Nuclear Information System (INIS)

    Van't Hof, J.

    1987-01-01

    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

  12. Bacterial Glycosyltransferases: Challenges and opportunities of a highly diverse enzyme class toward tailoring natural products

    Directory of Open Access Journals (Sweden)

    Jochen eSchmid

    2016-02-01

    Full Text Available The enzyme subclass of glycosyltransferases (EC 2.4 currently comprises 97 families as specified by CAZy classification. One of their important roles is in the biosynthesis of disaccharides, oligosaccharides and polysaccharides by catalyzing the transfer of sugar moieties from activated donor molecules to other sugar molecules. In addition glycosyltransferases also catalyze the transfer of sugar moieties onto aglycons, which is of great relevance for the synthesis of many high value natural products. Bacterial glycosyltransferases show a higher sequence similarity in comparison to mammalian ones. Even when most glycosyltransferases are poorly explored, state of the art technologies, such as protein engineering, domain swapping or computational analysis strongly enhance our understanding and utilization of these very promising classes of proteins. This perspective article will focus on bacterial glycosyltransferases, especially on classification, screening and engineering strategies to alter substrate specificity. The future development in these fields as well as obstacles and challenges will be highlighted and discussed.

  13. Radiation hormesis in higher plants

    International Nuclear Information System (INIS)

    Kim, Jae Sung

    1996-03-01

    The most remarkable aspect in the hormesis law is that low dose of harmful agents can produce effect that are diametrically opposite to the effect found with high doses of the same agent. Minute quantities of a harmful agent bring about very small change in the organism and control mechanisms appear to subjugate normal processes to place the organism in a state of alert and repair. The stimulated organism is more responsive to changes in environmental factors than it did before being alerted. Routine functions, including repair and defense, have priority for available energy and material. The alerted organism utilizes nutrients more efficiently, grows faster, shows improved defense reactions, matures faster, reproduces more effectively, has less disease, and lives longer. Accelerated germination, sprouting, growth, development, blooming and ripening, and increased crop yield and resistance to disease are found in plants. Another concept supported by the data is that low doses of ionizing radiation provide increased resistance to subsequent high doses of radiation. The hormesis varies with subject plant, variety, state of seed, environmental and cultural conditions, physiologic function measured, dose rate and total exposure. The results of hormesis are less consistently found, probably due to the great number of uncontrolled variables in the experiments. The general dosage for radiation hormesis in about 100 (10 to 1,000) times ambient or 100 (10 to 1,000) times less than a definitely harmful dose, but these must be modified to the occasion. Although little is known about most mechanisms of hormesis reaction, overcompensation of repair mechanism is offered as on mechanism. Radiation hormesis can provide more efficient use of resources, maximum production of foods, and increased health by the use of ionizing radiation as a useful tool in our technologic society. Efficient utilization of nature's resources demands support to explore the practical application of

  14. Radiation hormesis in higher plants

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae Sung [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1996-03-01

    The most remarkable aspect in the hormesis law is that low dose of harmful agents can produce effect that are diametrically opposite to the effect found with high doses of the same agent. Minute quantities of a harmful agent bring about very small change in the organism and control mechanisms appear to subjugate normal processes to place the organism in a state of alert and repair. The stimulated organism is more responsive to changes in environmental factors than it did before being alerted. Routine functions, including repair and defense, have priority for available energy and material. The alerted organism utilizes nutrients more efficiently, grows faster, shows improved defense reactions, matures faster, reproduces more effectively, has less disease, and lives longer. Accelerated germination, sprouting, growth, development, blooming and ripening, and increased crop yield and resistance to disease are found in plants. Another concept supported by the data is that low doses of ionizing radiation provide increased resistance to subsequent high doses of radiation. The hormesis varies with subject plant, variety, state of seed, environmental and cultural conditions, physiologic function measured, dose rate and total exposure. The results of hormesis are less consistently found, probably due to the great number of uncontrolled variables in the experiments. The general dosage for radiation hormesis in about 100 times ambient or 100 times less than a definitely harmful dose, but these must be modified to the occasion. Although little is known about most mechanisms of hormesis reaction, overcompensation of repair mechanism is offered as on mechanism. Radiation hormesis can provide more efficient use of resources, maximum production of foods, and increased health by the use of ionizing radiation as a useful tool in our technologic society. Efficient utilization of nature`s resources demands support to explore the practical application of radiation hormesis.

  15. Sterol glycosyltransferases--the enzymes that modify sterols.

    Science.gov (United States)

    Chaturvedi, Pankaj; Misra, Pratibha; Tuli, Rakesh

    2011-09-01

    Sterols are important components of cell membranes, hormones, signalling molecules and defense-related biotic and abiotic chemicals. Sterol glycosyltransferases (SGTs) are enzymes involved in sterol modifications and play an important role in metabolic plasticity during adaptive responses. The enzymes are classified as a subset of family 1 glycosyltransferases due to the presence of a signature motif in their primary sequence. These enzymes follow a compulsory order sequential mechanism forming a ternary complex. The diverse applications of sterol glycosides, like cytotoxic and apoptotic activity, anticancer activity, medicinal values, anti-stress roles and anti-insect and antibacterial properties, draws attention towards their synthesis mechanisms. Many secondary metabolites are derived from sterol pathways, which are important in defense mechanisms against pathogens. SGTs in plants are involved in changed sensitivity to stress hormones and their agrochemical analogs and changed tolerance to biotic and abiotic stresses. SGTs that glycosylate steroidal hormones, such as brassinosteroids, function as growth and development regulators in plants. In terms of metabolic roles, it can be said that SGTs occupy important position in plant metabolism and may offer future tools for crop improvement.

  16. Cytoplasniic differentiation during microsporogenesis in higher plants

    Directory of Open Access Journals (Sweden)

    H. Dichinnson

    2014-01-01

    Full Text Available Conspicuous cytoplasmic dedifferentiation in the pollen mother cells takes place early in the meiotic prophase of many plants. This event involves the removal of much of the cytoplasmic RNA. and the differentiation of both plastids and mitochondria to approaching the sole expression of their genomes. Much of the RNA removed from the cytoplasm passes to the nucleoplasm where it is utilised in the construction of a new `generation' of ribusomes. These new ribosomes are incorporated into cytoplasmic `nuclewhich disintegrate in the post-meiotic cytoplasm, restoring its ribosomes to pre-prophase levels. These changes are interpreted as evidence of a process by which the cytoplasm is cleansed of sporophytic control elements, both for the expression of the new gametophytic genome, and in the female cells of higher plants, for transmission to the new generation. The absence of control elements (presumably long-term messenger RNA from the cytoplasm would result in the dedifferentiation observed in the organelles, and the low levels of reserves in these cells presumably results in characteristically lengthy and unusual redifferentiation of both plastids and mitochondria, once information-carrying molecules again enter the cytosol.

  17. Mechanisms of male sterility in higher plants

    Energy Technology Data Exchange (ETDEWEB)

    Ohta, Yasuo [Tsukuba Univ., Sakura, Ibaraki (Japan)

    1982-03-01

    The mechanisms causing male sterility in higher plants were classified into two major categories: genetic and non-genetic. The former was further divided into six classes: 1) Anomality in spindle mechanism during meiosis, 2) chromosomal anomality such as haploidy, polyploidy, aneuploidy, chromosome some deficiency, inversion and reciprocal translocation, 3) presence of male sterile genes, 4) cytoplasmic abnormality, 5) the combination of some specific cytoplasm with particular genes, and 6) infections of microorganisms or viruses. Each mechanism was briefly explained, and the methods for the maintenance of parent lines for heterosis breeding and hybrid seed production were described. The non-genetic male sterility was classified into four types, which are caused by 1) low or high temperature, 2) water deficiency, 3) application of chemicals, and 4) radiation, with a brief explanation given for each of them.

  18. Mechanisms of male sterility in higher plants

    International Nuclear Information System (INIS)

    Ohta, Yasuo

    1982-01-01

    The mechanisms causing male sterility in higher plants were classified into two major categories: genetic and non-genetic. The former was further divided into six classes: 1) Anomality in spindle mechanism during meiosis, 2) chromosomal anomality such as haploidy, polyploidy, aneuploidy, chromosome some deficiency, inversion and reciprocal translocation, 3) presence of male sterile genes, 4) cytoplasmic abnormality, 5) the combination of some specific cytoplasm with particular genes, and 6) infections of microorganisms or viruses. Each mechanism was briefly explained, and the methods for the maintenance of parent lines for heterosis breeding and hybrid seed production were described. The non-genetic male sterility was classified into four types, which are caused by 1) low or high temperature, 2) water deficiency, 3) application of chemicals, and 4) radiation, with a brief explanation given for each of them. (Kaihara, S.)

  19. The cytoskeleton and gravitropism in higher plants

    Science.gov (United States)

    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. Classification, Naming and Evolutionary History of Glycosyltransferases from Sequenced Green and Red Algal Genomes

    Science.gov (United States)

    Ulvskov, Peter; Paiva, Dionisio Soares; Domozych, David; Harholt, Jesper

    2013-01-01

    The Archaeplastida consists of three lineages, Rhodophyta, Virideplantae and Glaucophyta. The extracellular matrix of most members of the Rhodophyta and Viridiplantae consists of carbohydrate-based or a highly glycosylated protein-based cell wall while the Glaucophyte covering is poorly resolved. In order to elucidate possible evolutionary links between the three advanced lineages in Archaeplastida, a genomic analysis was initiated. Fully sequenced genomes from the Rhodophyta and Virideplantae and the well-defined CAZy database on glycosyltransferases were included in the analysis. The number of glycosyltransferases found in the Rhodophyta and Chlorophyta are generally much lower then in land plants (Embryophyta). Three specific features exhibited by land plants increase the number of glycosyltransferases in their genomes: (1) cell wall biosynthesis, the more complex land plant cell walls require a larger number of glycosyltransferases for biosynthesis, (2) a richer set of protein glycosylation, and (3) glycosylation of secondary metabolites, demonstrated by a large proportion of family GT1 being involved in secondary metabolite biosynthesis. In a comparative analysis of polysaccharide biosynthesis amongst the taxa of this study, clear distinctions or similarities were observed in (1) N-linked protein glycosylation, i.e., Chlorophyta has different mannosylation and glucosylation patterns, (2) GPI anchor biosynthesis, which is apparently missing in the Rhodophyta and truncated in the Chlorophyta, (3) cell wall biosynthesis, where the land plants have unique cell wall related polymers not found in green and red algae, and (4) O-linked glycosylation where comprehensive orthology was observed in glycosylation between the Chlorophyta and land plants but not between the target proteins. PMID:24146880

  1. Exploring the functional significance of sterol glycosyltransferase enzymes.

    Science.gov (United States)

    Singh, Gaurav; Dhar, Yogeshwar Vikram; Asif, Mehar Hasan; Misra, Pratibha

    2018-01-01

    Steroidal alkaloids (SAs) are widely synthesized and distributed in plants manifesting as natural produce endowed with potential for medicinal, pesticidal and other high-value usages. Glycosylation of these SAs raises complex and diverse glycosides in plant cells that indeed govern numerous functional aspects. During the glycosylation process of these valuable metabolites, the addition of carbohydrate molecule(s) is catalyzed by enzymes known as sterol glycosyltransferases (SGTs), commonly referred to as UGTs, leading to the production of steryl glycosides (SGs). The ratio of SGs and nonglyco-conjugated SAs are different in different plant species, however, their biosynthesis in the cell is controlled by different environmental factors. The aim of this review is to evaluate the current SGT enzyme research and the functional consequences of glycomodification of SAs on the physiology and plant development, which together are associated with the plant's primary processes. Pharmaceutical, industrial, and other potential uses of saponins have also been discussed and their use in therapeutics has been unveiled by in silico analysis. The field of biotransformation or conversion of nonglycosylated to glycosylated phytosterols by the activity of SGTs, making them soluble, available and more useful for humankind is the new field of interest towards drug therapy. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Transfer action of cyclodextrin glycosyltransferase on starch

    Energy Technology Data Exchange (ETDEWEB)

    Kitahata, S; Okada, S [Osaka City Technical Research Inst. (Japan)

    1975-11-01

    The transglycosylation reaction of the cyclodextrin glycosyltransferase from Bacillus megaterium (No. 5 enzyme) and Bacillus macerans (BMA) were examined. No.5 enzyme was more efficient in transglycosylation reaction than BMA in the every acceptor employed in the present study. The order of the efficient acceptors for No. 5 enzyme was maltose (G2), glucose (G1), maltotriose (G3) and sucrose (GF). On the other hand, that found for BMA was G1, G2, GF and G3. The transglycosylation products to glucose formed by the action of No. 5 enzyme on starch were G2, G3, maltotetraose (G4), maltopentaose (G5), maltohexaose (G6) and maltoheptaose (G7) in the order of their quantities, while, in the case of BMA, they were G2, G3, G5, G7 = G4 and G6. The larger transglycosylation products to sucrose formed by the action of No. 5 enzyme on starch were maltosylfructose. On the other hand, that formed by the action of BMA was maltoheptaosylfructose. It was suggested that cyclodextrin glycosyltransferase could transfer the glucosyl residues to an acceptor directly from starch, as well as through cyclodextrin.

  3. Screening of recombinant glycosyltransferases reveals the broad acceptor specificity of stevia UGT-76G1.

    Science.gov (United States)

    Dewitte, Griet; Walmagh, Maarten; Diricks, Margo; Lepak, Alexander; Gutmann, Alexander; Nidetzky, Bernd; Desmet, Tom

    2016-09-10

    UDP-glycosyltransferases (UGTs) are a promising class of biocatalysts that offer a sustainable alternative for chemical glycosylation of natural products. In this study, we aimed to characterize plant-derived UGTs from the GT-1 family with an emphasis on their acceptor promiscuity and their potential application in glycosylation processes. Recombinant expression in E. coli provided sufficient amounts of enzyme for the in-depth characterization of the salicylic acid UGT from Capsella rubella (UGT-SACr) and the stevia UGT from Stevia rebaudiana (UGT-76G1Sr). The latter was found to have a remarkably broad specificity with activities on a wide diversity of structures, from aliphatic and branched alcohols, over small phenolics to larger flavonoids, terpenoids and even higher glycoside compounds. As an example for its industrial potential, the glycosylation of curcumin was thoroughly evaluated. Under optimized conditions, 96% of curcumin was converted within 24h into the corresponding curcumin β-glycosides. In addition, the reaction was performed in a coupled system with sucrose synthase from Glycine max, to enable the cost-efficient (re)generation of UDP-Glc from sucrose as abundant and renewable resource. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Computational identification of candidate nucleotide cyclases in higher plants

    KAUST Repository

    Wong, Aloysius Tze; Gehring, Christoph A

    2013-01-01

    In higher plants guanylyl cyclases (GCs) and adenylyl cyclases (ACs) cannot be identified using BLAST homology searches based on annotated cyclic nucleotide cyclases (CNCs) of prokaryotes, lower eukaryotes, or animals. The reason is that CNCs

  5. Glycosyltransferase glycosylating flavokermesic acid and/or kermesic acid

    DEFF Research Database (Denmark)

    2016-01-01

    An isolated glycosyltransferase (GT) polypeptide capable of: (I) : conjugating glucose to flavokermesic acid (FK); and/or (II) : conjugating glucose to kermesic acid (KA) and use of this GT to e.g. make Carminic acid.......An isolated glycosyltransferase (GT) polypeptide capable of: (I) : conjugating glucose to flavokermesic acid (FK); and/or (II) : conjugating glucose to kermesic acid (KA) and use of this GT to e.g. make Carminic acid....

  6. GLYCOSYLTRANSFERASE GLYCOSYLATING FLAVOKERMESIC ACID AND/OR KERMESIC ACID

    DEFF Research Database (Denmark)

    2015-01-01

    An isolated glycosyltransferase (GT) polypeptide capable of: (I): conjugating glucose to flavokermesic acid (FK); and/or (II): conjugating glucose to kermesic acid (KA) and use of this GT to e.g. make Carminic acid.......An isolated glycosyltransferase (GT) polypeptide capable of: (I): conjugating glucose to flavokermesic acid (FK); and/or (II): conjugating glucose to kermesic acid (KA) and use of this GT to e.g. make Carminic acid....

  7. Assimilation and transformation of benzene by higher plants

    Energy Technology Data Exchange (ETDEWEB)

    Durmishidze, S V; Ugrekhelidze, D Sh; Dzhikiya, A N

    1974-01-01

    Higher plants are capable of assimilating benzene, the molecules of which are subjected to deep chemical transformations; the products of its metabolism move along the plant. Taking part in total metabolism, carbon atoms of benzene molecules incorporate into composition of low-molecular compounds of the plant cell. The bulk of benzene carbon incorporates into composition of organic acids and a comparatively small part - into composition of amino acids. In the metabolism process benzene carbon localizes mainly in the chloroplasts. Phenol, muconic acid and CO/sub 2/ are isolated and identified from the products of benzene enzymatic oxidation. A range of benzene assimilation by higher plants is extremely wide. 9 references, 5 tables.

  8. Ecological Risk Assessment of Genetically Modified Higher Plants (GMHP)

    DEFF Research Database (Denmark)

    Kjær, C.; Damgaard, C.; Kjellsson, G.

    Preface This publication is a first version of a manual identifying the data needs for ecological risk assessment of genetically modified higher plants (GMHP). It is the intention of the authors to stimulate further discussion of what data are needed in order to conduct a proper ecological risk...... of the project Biotechnology: elements in environmental risk assessment of genetically modified plants. December 1999 Christian Kjær Introduction In ecological risk assessment of transgenic plants, information on a wide range of subjects is needed for an effective and reliable assessment procedure...... in the amendment to the directive. This report suggests a structured way to identify the type of data needed to perform a sound ecological risk assessment for genetically modified higher plants (GMHP). The identified data types are intended to support the evaluation of the following risks: risk of invasion...

  9. Higher Plants in Space: Microgravity Perception, Response, and Adaptation

    Science.gov (United States)

    Zheng, Hui Qiong; Han, Fei; Le, Jie

    2015-11-01

    Microgravity is a major abiotic stress in space. Its effects on plants may depend on the duration of exposure. We focused on two different phases of microgravity responses in space. When higher plants are exposed to short-term (seconds to hours) microgravity, such as on board parabolic flights and sounding rockets, their cells usually exhibit abiotic stress responses. For example, Ca 2+-, lipid-, and pH-signaling are rapidly enhanced, then the production of reactive oxygen species and other radicals increase dramatically along with changes in metabolism and auxin signaling. Under long-term (days to months) microgravity exposure, plants acclimatize to the stress by changing their metabolism and oxidative response and by enhancing other tropic responses. We conclude by suggesting that a systematic analysis of regulatory networks at the molecular level of higher plants is needed to understand the molecular signals in the distinct phases of the microgravity response and adaptation.

  10. UGT74D1 is a novel auxin glycosyltransferase from Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Shang-Hui Jin

    Full Text Available Auxin is one type of phytohormones that plays important roles in nearly all aspects of plant growth and developmental processes. The glycosylation of auxins is considered to be an essential mechanism to control the level of active auxins. Thus, the identification of auxin glycosyltransferases is of great significance for further understanding the auxin regulation. In this study, we biochemically screened the group L of Arabidopsis thaliana glycosyltransferase superfamily for enzymatic activity toward auxins. UGT74D1 was identified to be a novel auxin glycosyltransferase. Through HPLC and LC-MS analysis of reaction products in vitro by testing eight substrates including auxins and other compounds, we found that UGT74D1 had a strong glucosylating activity toward indole-3-butyric acid [IBA], indole-3-propionic acid [IPA], indole-3-acetic acid [IAA] and naphthaleneacetic acid [NAA], catalyzing them to form corresponding glucose esters. Biochemical characterization showed that this enzyme had a maximum activity in HEPES buffer at pH 6.0 and 37°C. In addition, the enzymatic activity analysis of crude protein and the IBA metabolite analysis from transgenic Arabidopsis plants overexpressing UGT74D1 gene were also carried out. Experimental results indicated that over-production of the UGT74D1 in plants indeed led to increased level of the glucose conjugate of IBA. Moreover, UGT74D1 overexpression lines displayed curling leaf phenotype, suggesting a physiological role of UGT74D1 in affecting the activity of auxins. Our current data provide a new target gene for further genetic studies to understand the auxin regulation by glycosylation in plants.

  11. Computational identification of candidate nucleotide cyclases in higher plants

    KAUST Repository

    Wong, Aloysius Tze

    2013-09-03

    In higher plants guanylyl cyclases (GCs) and adenylyl cyclases (ACs) cannot be identified using BLAST homology searches based on annotated cyclic nucleotide cyclases (CNCs) of prokaryotes, lower eukaryotes, or animals. The reason is that CNCs are often part of complex multifunctional proteins with different domain organizations and biological functions that are not conserved in higher plants. For this reason, we have developed CNC search strategies based on functionally conserved amino acids in the catalytic center of annotated and/or experimentally confirmed CNCs. Here we detail this method which has led to the identification of >25 novel candidate CNCs in Arabidopsis thaliana, several of which have been experimentally confirmed in vitro and in vivo. We foresee that the application of this method can be used to identify many more members of the growing family of CNCs in higher plants. © Springer Science+Business Media New York 2013.

  12. Evolution of glycosaminoglycans and their glycosyltransferases: Implications for the extracellular matrices of animals and the capsules of pathogenic bacteria.

    Science.gov (United States)

    DeAngelis, Paul L

    2002-11-01

    Glycosaminoglycans (linear polysaccharides with a repeating disaccharide backbone containing an amino sugar) are essential components of extracellular matrices of animals. These complex molecules play important structural, adhesion, and signaling roles in mammals. Direct detection of glycosaminoglycans has been reported in a variety of organisms, but perhaps more definitive tests for the glycosyltransferase genes should be utilized to clarify the distribution of glycosaminoglycans in metazoans. Recently, glycosyltransferases that form the hyaluronan, heparin/heparan, or chondroitin backbone were identified at the molecular level. The three types of glycosyltransferases appear to have evolved independently based on sequence comparisons and other characteristics. All metazoans appear to possess heparin/heparan. Chondroitin is found in some worms, arthropods, and higher animals. Hyaluronan is found only in two of the three main branches of chordates. The presence of several types of glycosaminoglycans in the body allows multiple communication channels and adhesion systems to operate simultaneously. Certain pathogenic bacteria produce extracellular coatings, called capsules, which are composed of glycosaminoglycans that increase their virulence during infection. The capsule helps shield the microbe from the host defenses and/or modulates host physiology. The bacterial and animal polysaccharides are chemically identical or at least very similar. Therefore, no immune response is generated, in contrast to the vast majority of capsular polymers from other bacteria. In microbial systems, it appears that in most cases functional convergent evolution of glycosaminoglycan glycosyltransferases occurred, rather than direct horizontal gene transfer from their vertebrate hosts. Copyright 2002 Wiley-Liss, Inc.

  13. Predicting molybdenum toxicity to higher plants: Influence of soil properties

    Energy Technology Data Exchange (ETDEWEB)

    McGrath, S.P., E-mail: steve.mcgrath@bbsrc.ac.u [Soil Science Department, Centre for Soils and Ecosystems Functions, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ (United Kingdom); Mico, C. [Soil Science Department, Centre for Soils and Ecosystems Functions, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ (United Kingdom); Curdy, R. [Laboratory for Environmental Biotechnology (LBE), Swiss Federal Institute of Technology Lausanne (EPFL) Station 6 CH, 1015 Lausanne (Switzerland); Zhao, F.J. [Soil Science Department, Centre for Soils and Ecosystems Functions, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ (United Kingdom)

    2010-10-15

    The effect of soil properties on the toxicity of molybdenum (Mo) to four plant species was investigated. Soil organic carbon or ammonium-oxalate extractable Fe oxides were found to be the best predictors of the 50% effective dose (ED{sub 50}) of Mo in different soils, explaining > 65% of the variance in ED{sub 50} for four species except for ryegrass (26-38%). Molybdenum concentrations in soil solution and consequently plant uptake were increased when soil pH was artificially raised because sorption of Mo to amorphous oxides is greatly reduced at high pH. The addition of sulphate significantly decreased Mo uptake by oilseed rape. For risk assessment, we suggest that Mo toxicity values for plants should be normalised using soil amorphous iron oxide concentrations. - Amorphous iron oxides or organic carbon were found to be the best predictors of the toxicity threshold values of Mo to higher plants on different soils.

  14. Predicting molybdenum toxicity to higher plants: Influence of soil properties

    International Nuclear Information System (INIS)

    McGrath, S.P.; Mico, C.; Curdy, R.; Zhao, F.J.

    2010-01-01

    The effect of soil properties on the toxicity of molybdenum (Mo) to four plant species was investigated. Soil organic carbon or ammonium-oxalate extractable Fe oxides were found to be the best predictors of the 50% effective dose (ED 50 ) of Mo in different soils, explaining > 65% of the variance in ED 50 for four species except for ryegrass (26-38%). Molybdenum concentrations in soil solution and consequently plant uptake were increased when soil pH was artificially raised because sorption of Mo to amorphous oxides is greatly reduced at high pH. The addition of sulphate significantly decreased Mo uptake by oilseed rape. For risk assessment, we suggest that Mo toxicity values for plants should be normalised using soil amorphous iron oxide concentrations. - Amorphous iron oxides or organic carbon were found to be the best predictors of the toxicity threshold values of Mo to higher plants on different soils.

  15. Chlorine-containing natural compounds in higher plants

    DEFF Research Database (Denmark)

    Engvild, Kjeld Christensen

    1986-01-01

    More than 130 chlorine-containing compounds have been isolated from higher plants and ferns; about half are polyacetylenes, thiophenes and sesquiterpene lactones from the Asteraceae. A chlorinated chlorophyll may be an important part of photosystem 1. High biological activity is found in 4...

  16. Higher plant vegetation changes during Pliocene sapropel formation

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Menzel, D.; Schouten, S.; Bergen, P.F. van

    2004-01-01

    The 13C values of higher plant wax C27 33 n-alkanes were determined in three, time-equivalent Pliocene (2.943 Ma) sapropels and homogeneous calcareous ooze from three different sites forming an east-west transect in the eastern Mediterranean Basin in order to study the composition of the vegetation

  17. Functional architecture of higher plant photosystem II supercomplexes

    NARCIS (Netherlands)

    Caffarri, Stefano; Kouril, Roman; Kereiche, Sami; Boekema, Egbert J.; Croce, Roberta; Kereïche, Sami

    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

  18. Uptake and distribution of mercury within higher plants

    Energy Technology Data Exchange (ETDEWEB)

    Beauford, W; Barber, J; Barringer, A R

    1977-04-15

    The uptake and distribution of inorganic mercury (HgCl/sub 2/) within higher plants (Pisum sativum and Mentha spicata) was examined using solution culture and radiotracer techniques. Plants were found to tolerate an external level of 1 mgHg/kg of solution but both physiological and biochemical processes were affected at 5 mgHg/kg and 10 mgHg/kg. The uptake of Hg into plants grown in hydroponic solution was a function of external concentration. Over the concentration range considered the accumulation of Hg in the roots was linear on a log-log basis although the uptake of the element into the shoots appeared to be two-phased. The distribution of Hg in plants was asymmetrical with much greater amounts of the element in the roots than the shoots. Although the level of Hg increased generally in plant tissues with increasing external levels, the proportion retained in the roots, relative to the shoots, was constant (approximately 95%). Two binding characteristics of the Hg within plant tissue were detected. A major proportion of Hg was tightly bound, being unaffected by treatment with ethanol and hydrochloric acid. The remaining Hg in the tissue was removed by either water or hydrochloric acid treatment. Cell fractionation indicated that the major binding component of Hg in plant tissues was the cell wall.

  19. Novel Occurrence of Uncommon Polyamines in Higher Plants 1

    Science.gov (United States)

    Kuehn, Glenn D.; Rodriguez-Garay, Benjamin; Bagga, Suman; Phillips, Gregory C.

    1990-01-01

    Diamines and polyamines are ubiquitous components of living cells, and apparently are involved in numerous cellular and physiological processes. Certain “uncommon” polyamines have limited distribution in nature and have been associated primarily with organisms adapted to extreme environments, although the precise function of these polyamines in such organisms is unknown. This article summarizes current knowledge regarding the occurrence in higher plants of the uncommon polyamines related to and including norspermidine and norspermine. A putative biosynthetic pathway to account for the occurrences of these uncommon polyamines in higher plants is presented, with a summary of the supporting evidence indicating the existence of the requisite enzymatic activities in alfalfa, Medicago sativa L. PMID:16667862

  20. Inositol trisphosphate receptor in higher plants: is it real?

    Czech Academy of Sciences Publication Activity Database

    Krinke, Ondřej; Novotná, Z.; Valentová, O.; Martinec, Jan

    2007-01-01

    Roč. 58, č. 3 (2007), s. 361-376 ISSN 0022-0957 R&D Projects: GA MŠk(CZ) LC06034 Institutional research plan: CEZ:AV0Z50380511 Source of funding: V - iné verejné zdroje Keywords : Ca2+ signalling * higher plants * inositol trisphosphate receptor Subject RIV: EF - Botanics Impact factor: 3.917, year: 2007

  1. Functional architecture of higher plant photosystem II supercomplexes

    OpenAIRE

    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. Ch...

  2. Use of higher plants as screens for toxicity assessment.

    Science.gov (United States)

    Kristen, U

    1997-01-01

    This review deals with the use of entire plants, seedlings, cell suspension cultures and pollen tubes for the estimation of potential toxicity in the environment, and for risk assessment of chemicals and formulations of human relevance. It is shown that the roots of onions and various crop seedlings, as well as in vitro growing pollen tubes of some mono- and dicotyledonous plants, are most frequently used to obtain toxicity data by determination of root and tube growth inhibition. Both roots and pollen tubes are chloroplast free, non-photosynthetic systems and, therefore, with regard to their cytotoxic reactions are closer to vertebrate tissues and cells than are chloroplast-containing plant organs. Root tips and anthers of flower buds are shown to be applicable to genotoxicity screening by microscopic analysis of mitotic or meiotic aberrations during cell division or microspore development, respectively. The processes of mitosis and meiosis are similar in plants and animals. Therefore, meristematic and sporogenic tissues of plants generally show patterns of cytotoxic response similar to those of embryogenic and spermatogenic tissues of vertebrates. The suitability of root tips, cell suspensions and pollen tubes for the investigation of mechanisms of toxic action and for the analysis of structure-activity relationships is also demonstrated. Two plant-based assays, the Allium test and the pollen tube growth test, both currently being evaluated alongside with established mammalian in vivo and in vitro protocols, are emphasized with regard to their potential use as alternatives to animal in vivo toxicity tests. For both assays, preliminary results indicate that the tips of growing roots and the rapidly elongating pollen tubes of certain higher plant species are as reliable as mammalian cell lines for detecting basal cytotoxicity. It is suggested that seeds and pollen grains, in particular, provide easily storable and convenient systems for inexpensive, relatively

  3. Sucrose synthase: A unique glycosyltransferase for biocatalytic glycosylation process development.

    Science.gov (United States)

    Schmölzer, Katharina; Gutmann, Alexander; Diricks, Margo; Desmet, Tom; Nidetzky, Bernd

    2016-01-01

    Sucrose synthase (SuSy, EC 2.4.1.13) is a glycosyltransferase (GT) long known from plants and more recently discovered in bacteria. The enzyme catalyzes the reversible transfer of a glucosyl moiety between fructose and a nucleoside diphosphate (NDP) (sucrose+NDP↔NDP-glucose+fructose). The equilibrium for sucrose conversion is pH dependent, and pH values between 5.5 and 7.5 promote NDP-glucose formation. The conversion of a bulk chemical to high-priced NDP-glucose in a one-step reaction provides the key aspect for industrial interest. NDP-sugars are important as such and as key intermediates for glycosylation reactions by highly selective Leloir GTs. SuSy has gained renewed interest as industrially attractive biocatalyst, due to substantial scientific progresses achieved in the last few years. These include biochemical characterization of bacterial SuSys, overproduction of recombinant SuSys, structural information useful for design of tailor-made catalysts, and development of one-pot SuSy-GT cascade reactions for production of several relevant glycosides. These advances could pave the way for the application of Leloir GTs to be used in cost-effective processes. This review provides a framework for application requirements, focusing on catalytic properties, heterologous enzyme production and reaction engineering. The potential of SuSy biocatalysis will be presented based on various biotechnological applications: NDP-sugar synthesis; sucrose analog synthesis; glycoside synthesis by SuSy-GT cascade reactions. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. Consideration of higher seismic loads at existing plants

    Energy Technology Data Exchange (ETDEWEB)

    Liebig, J.; Pellissetti, M.

    2015-07-01

    Because of advancement of methods in probabilistic seismic hazard analysis, plenty of existing plants face higher seismic loads as an obligation from the national authorities. In case of such obligations safety related structures and equipment have to be reevaluated or requalified for the increased seismic loads. The paper provides solutions for different kinds of structures and equipment inside the plant, avoiding cost intensive hardware exchange. Due to higher seismic loads different kinds of structures and equipment inside a plant have to be reevaluated. For civil structures, primary components, mechanical components, distribution lines and electrical and I&C equipment different innovative concepts will be applied to keep structures and equipment qualified for the higher seismic loads. Detailed analysis, including the modeling of non-linear phenomena, or minor structural upgrades are cost competitive, compared to cost intensive hardware exchanges. Several case studies regarding the re-evaluation and requalification of structures and equipment due to higher seismic loads are presented. It is shown how the creation of coupled finite element models and the consistent propagation of acceleration time histories through the soil, building and primary circuit lead to a significant load reduction Electrical and I&C equipment is reinforced by smart upgrades which increase the natural equipment frequencies. Therefore for all devices inside the cabinets the local acceleration will not increase and the seismic qualification will be maintained. The case studies cover both classical deterministic and probabilistic re-evaluations (fragility analysis). Furthermore, the substantial benefits of non-linear limit load evaluation, such as push-over analysis of buildings and limit load analysis of fuel assemblies, are demonstrated. (Author)

  5. Mutation induction by ion beams in higher plants

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Atsushi [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2003-04-01

    This review mainly describes study results obtained in the Takasaki ion-beam (IB) irradiation facility (TIARA) on the mutation induction in higher plants. Biological effects like lethality and on budding of IBs (carbon, Ne and Ar) are discussed in relation with their linear energy transfer (LET), relative biological effectiveness and the developmental states in shepherd's-purse and tobacco. Induced mutation by IB are characterized by those findings that the mutation rate by C beam is 1.9 x 10{sup -6}, being 17 times higher than the electron beam, in the shepherd's-purse, that C beam induces larger structural changes than electron beam when examined by molecular mechanism of tt and gl gene mutations, and that mutation spectrum of IB is different from that of {gamma}-ray and is wider. Novel mutants are described on shepherd's-purse (pigment mutants, ultraviolet (UV)-resistant and sensitive ones, and flowering ones), disease-resistant rice, barley and tobacco plants, and flowering plants. IB mutation is possibly useful for solving the problems of environment and foods in future. (N.I.)

  6. Cloning higher plants from aseptically cultured tissues and cells

    Science.gov (United States)

    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.

  7. Engineering of factors determining alpha-amylase and cyclodextrin glycosyltransferase specificity in the cyclodextrin glycosyltransferase from Thermoanaerobacterium thermosulfurigenes EM1

    NARCIS (Netherlands)

    Wind, RD; Buitelaar, RM; Dijkhuizen, L

    1998-01-01

    The starch-degrading enzymes alpha-amylase and cyclodextrin glycosyltransferase (CGTase) are functionally and structurally closely related, with CGTases containing two additional domains (called D and E) compared to the three domains of alpha-amylases (A, B and C). Amino acid residue 196

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

    Science.gov (United States)

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

    2016-01-11

    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.

  9. Functional architecture of higher plant photosystem II supercomplexes.

    Science.gov (United States)

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

    2009-10-07

    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 C(2)S(2)M(2) 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 C(2)S(2)M(2) at 12 A 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.

  10. Features of fatty acid synthesis in higher plants

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, M [Tokyo Univ. (Japan). Coll. of General Education; Nakamura, Y

    1975-07-01

    In the biosynthesis of fatty acid in the presence of /sup 3/H/sub 2/O, /sup 3/H is incorporated into the hydrocarbon chain of the fatty acid. The features in the fatty acid synthesis of higher plants were investigated by applying /sup 3/H/sub 2/O method to the measurement of the ability of spinach leaves synthesizing fatty acid. Sucrose, acetate, pyruvate, PGA, PEP, OAA, citrate, etc. were employed as the substrates of fatty acid synthesis to trace the process of synthesis of each fatty acid. The demand of various cofactors related to the ability of spinach chloroplast fatty acid synthesizing was also examined. Light dependence of the fatty acid synthesis of chloroplast as well as the influences of N,N'-dicyclohexyl carbodiimide, carbonylcyanide-4-trifluoromethoxy phenyl hydrazone and NH/sub 4/Cl were discussed. The results were compared with the reports on the fatty acid synthesis of avocado pear, castor bean, etc.

  11. DNA repair in mutagen-injured higher plants

    International Nuclear Information System (INIS)

    Veleminsky, J.; Gichner, T.

    1978-01-01

    Data are summarized proving the occurrence of photoreactivation of UV-induced pyrimidine dimers in cells of Nicotiana tabucum, Gingko and carrot, the excision of dimers in cells of Nicotiana tabacum, Gingko and carrot, the excision of dimers in protoplasts of carrot and in embryos of Lathyrus sativus, and the repair of DNA single-strand breaks induced in carrot protoplasts and barley embryonic cells by ionizing radiation. In irradiated barley embryos the unscheduled DNA synthesis and higher accessibility of induced primers to DNA polymerase I of E. coli were observed preferentially in G 1 cells with diffused chromatin. These reactions were inhibited by caffeine and EDTA. Unscheduled DNA synthesis was also observed in synchronized irradiated root cuttings of Vicia faba and in barley embryos treated with 4-nitroquinoline oxide, the latter being inhibited by caffeine and hydroxyurea. Repair synthesis was also established in barley embryos treated with mutagenic N-methyl-N-nitrosourea under conditions that postponed the onset of germination after the treatment. The same conditions enhanced the repair of DNA single-strand breaks induced by this mutagen and several other monofunctional alkylating compounds. From tissues of barley and of Phaseolus multiflorus, endonucleases for apurinic sites were isolated and characterized. Some of them are located in chromatin, others in chloroplasts. The relation between DNA repair and genetic effects of mutagens in higher plants is also discussed. (Auth.)

  12. Higher plants as biomonitors of radionuclides in urban air

    International Nuclear Information System (INIS)

    Ajtic, J.; Todorovic, D.; Popovic, D.; Nikolic, J.

    2011-01-01

    Two deciduous tree genera, linden (Tilia tomentosa L. and Tilia cordata Mill.) and chestnut (Aesculus hippocastanum L.), are analysed as biomonitors of 210 Pb and 7 Be in air. In a multi year study (2002 - 2009), conducted in three city parks in Belgrade, the content of 210 Pb and 7 Be in samples of leaves of linden and chestnut trees, and aerosols was determined on an HPGe detector by standard gamma spectrometry. The differences seen in the radionuclides' activities across the measurement sites and between the tree genera are not significant, suggesting that the micro climate, level of air pollution and physiological characteristics of the trees have a negligible effect on the radionuclides' activities in leaves. Linear Pearson's correlation coefficients are used to correlate the 210 Pb and 7 Be activities in aerosols and in leaves. The results show that linden could be used as a 210 Pb biomonitor which provides information on the recent history of exposure. No large positive correlation is found for the 7 Be activities in leaves and aerosols, indicating that higher plants are not a suitable biomonitor for this radionuclide. [sr

  13. Plant design aspects of catalytic biosyngas conversion to higher alcohols

    International Nuclear Information System (INIS)

    Atsonios, K.; Christodoulou, Ch.; Koytsoumpa, E.-I.; Panopoulos, K.D.; Kakaras, Em.

    2013-01-01

    Although biomethanol production has attracted most of the attention in the past years, there is a current trend for the synthesis of higher alcohols (i.e. ethanol, plus C 3 –C 4 ) from biomass gasification. These compounds could be used directly as fuel or fuel additives for octane or cetane number enhancement. These also serve as important intermediates for the chemical industry. In this paper a comparison is performed between the different process configurations a higher alcohols production plant from biomass gasification can take. These options are modelled in Aspenplus™; all steps and important unit operations are presented with the aim to correctly evaluate the peripheral energy requirements and conclude with the overall thermodynamic limitations of the processes. The differentiation between black liquor and solid biomass gasification, the type of catalyst employed, and the effect of the recycling scheme adopted for the reutilization of unreacted syngas are evaluated. The design has to cope with the limited yields and poor selectivity of catalysts developed so far. The gas cleaning is different depending on the different requirements of the catalysts as far as H 2 S purity. The process modelling results reveal that the hydrogenation of CO to higher alcohols is favoured by high pressure, temperature around 325 °C and high reactor residence times. A biorefinery using modified Fisher–Tropsch (FT) catalysts (MoS 2 ) prevail over modified MeOH catalyst (Cu–Zn based) for HA production. The efficiency of HA production in HHV terms can reach up to 25%. -- Graphical abstract: Process flow diagrams of different biorefinery systems derived from a) woody biomass and b) black liquor. Highlights: ► An integrated gasification/gas-cleaning/synthesis system was modelled in Aspenplus. ► HA production from wood and black liquor gasification is compared. ► Modified FT catalysts prevail over modified methanol catalyst for HA production. ► HA productivity is

  14. Absorption and conversion of nitrogen dioxide by higher plants

    International Nuclear Information System (INIS)

    Durmishidze, S.V.; Nutsubidze, N.N.

    1976-01-01

    An investigation was performed to study the ability of plants to absorb and metabolize NO 2 , as well as to reduce and incorporate nitrogen into amino acid molecules. Experiments on the absorption of NO 2 labeled with 15 N were conducted in special chambers, both on whole plants and on fresh-cut branches. NO 2 was used in various concentrations from 0.01 to 5% of the volume. The exposure of the experiments ranged from 5 min to 7 days, involving more than 60 species of perennial and annual plants. The processes of assimilation and conversion of NO 2 from the air to amino acids by plants are related. The conversion scheme showed close association with physiological state of the plant and with external factors of its vital activity. It is conceivable that plants that intensively absorb and convert oxides of nitrogen and give a large biomass can be used for the purification air

  15. The molecular basis of disease resistance in higher plants

    African Journals Online (AJOL)

    xxxxxx

    Therefore, manipulating a single transcription factor could have the same effect as manipulating a set of specific genes within the plant. As highlighted above, transgenic plants allow the targeted ... including molecular techniques and genetics will provide insights into pathogen-defense mechanism and subsequent disease ...

  16. Cesium-137 accumulation in higher plants before and after Chernobyl

    International Nuclear Information System (INIS)

    Sawidis, T.; Drossos, E.; Papastefanou, C.; Heinrick, G.

    1990-01-01

    Cesium-137 concentrations in plant species of three biotypes of northern Greece, differing in location as well as in vegetation, are reported following the Chernobyl reactor accident. The cesium uptake by plants was due to the foliar deposition rather than the root uptake. The highest level of cesium in plants was found in Ranunculus sardous, a pubescent plant. The 137 Cs concentration was about 22kBq kg -1 d.w. A high level of cesium was also found in Salix alba ( 137 Cs: 19.6 kBq kg -1 d.w.), a deciduous tree showing that hairy leaves or leaves having rough and large surfaces can absorb greater amounts of radioactivity (surface effect). A comparison is also made between the results of measurements of the present study and the results of measurements of some herbarium plants collected one year before the accident as well as the results of measurements of some new plants grown and collected one year after the accident resulting in a natural removal rate of 137 Cs in plants varying from 14 to 130 days

  17. Reconciling functions and evolution of isoprene emission in higher plants.

    Science.gov (United States)

    Loreto, Francesco; Fineschi, Silvia

    2015-04-01

    Compilation and analysis of existing inventories reveal that isoprene is emitted by c. 20% of the perennial vegetation of tropical and temperate regions of the world. Isoprene emitters are found across different plant families without any clear phylogenetic thread. However, by critically appraising information in inventories, several ecological patterns of isoprene emission can be highlighted, including absence of emission from C4 and annual plants, and widespread emission from perennial and deciduous plants of temperate environments. Based on this analysis, and on available information on biochemistry, ecology and functional roles of isoprene, it is suggested that isoprene may not have evolved to help plants face heavy or prolonged stresses, but rather assists C3 plants to run efficient photosynthesis and to overcome transient and mild stresses, especially during periods of active plant growth in warm seasons. When the stress status persists, or when evergreen leaves cope with multiple and repeated stresses, isoprene biosynthesis is replaced by the synthesis of less volatile secondary compounds, in part produced by the same biochemical pathway, thus indicating causal determinism in the evolution of isoprene-emitting plants in response to the environment. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

  18. Higher plant acclimation to solar ultraviolet-B radiation

    International Nuclear Information System (INIS)

    Robberecht, R.

    1981-01-01

    The objectives of this study were to determine: (1) the relationship between plant sensitivity and epidermal uv attenuation, (2) the effect of phenotypic changes in the leaf epidermis, resulting from uv-B exposure, on plant sensitivity to uv radiation, and (3) the platicity of these changes in the epidermis leading to plant acclimation to uv-B radiation. A mechanism of uv-B attenuation, possibly involving the biosynthesis of uv-absorbing flavonoid compounds in the epidermis and mesophyll under the stress of uv-B radiation, and a subsequent increase in the uv-B attenuation capacity of the epidermis, is suggested. The degree of plant sensitivity and acclimation to natural and intensified solar uv-B radiation may involve a dynamic balance between the capacity for uv-B attenuation and uv-radiation-repair mechanisms in the leaf

  19. Purification and characterisation of Cyclodextrin glycosyltransferase ...

    African Journals Online (AJOL)

    EXPER

    2012-06-05

    Jun 5, 2012 ... require higher temperatures for the liquefaction of starch at which CGTases ... growth medium by centrifugation at 12000 x g for 15 min. Cell-free supernatant ..... 95°C, thermal inactivation was only 13% (Figure 3). Enzyme ...

  20. Root excretions in tobacco plants and possible implications on the Iron nutrition of higher plants

    Energy Technology Data Exchange (ETDEWEB)

    Wallace, A

    1969-01-01

    Several pieces of evidence indicate that riboflavin produced in roots and perhaps other compounds produced either in roots or in microorganisms can facilitate either or both the absorption and translocation of iron in higher plants. Riboflavin production and increased iron transport are characteristic of iron-deficient plants, both are decreased by nitrogen deficiency, both evidently can be regulated by a microorganism. When large amounts of iron was transported in the xylem exudate of tobacco, riboflavin was also. An excess of the chelating agent, EDTA, without iron seems to increase the iron uptake from an iron chelate, EDDHA. All these effects are probably related and knowledge of them may help solve iron deficiency problems in horticultural crops.

  1. Regulation of phosphate starvation responses in higher plants.

    Science.gov (United States)

    Yang, Xiao Juan; Finnegan, Patrick M

    2010-04-01

    Phosphorus (P) is often a limiting mineral nutrient for plant growth. Many soils worldwide are deficient in soluble inorganic phosphate (P(i)), the form of P most readily absorbed and utilized by plants. A network of elaborate developmental and biochemical adaptations has evolved in plants to enhance P(i) acquisition and avoid starvation. Controlling the deployment of adaptations used by plants to avoid P(i) starvation requires a sophisticated sensing and regulatory system that can integrate external and internal information regarding P(i) availability. In this review, the current knowledge of the regulatory mechanisms that control P(i) starvation responses and the local and long-distance signals that may trigger P(i) starvation responses are discussed. Uncharacterized mutants that have P(i)-related phenotypes and their potential to give us additional insights into regulatory pathways and P(i) starvation-induced signalling are also highlighted and assessed. An impressive list of factors that regulate P(i) starvation responses is now available, as is a good deal of knowledge regarding the local and long-distance signals that allow a plant to sense and respond to P(i) availability. However, we are only beginning to understand how these factors and signals are integrated with one another in a regulatory web able to control the range of responses demonstrated by plants grown in low P(i) environments. Much more knowledge is needed in this agronomically important area before real gains can be made in improving P(i) acquisition in crop plants.

  2. Risks of increased UV-B radiation: higher plants

    International Nuclear Information System (INIS)

    Rau, W.; Hofmann, H.

    1994-01-01

    The question pursued within the Bavarian climate research programme (BayFORKLIM) in the present context was as follows: Does the fact that UV-B radiation increases with growing site elevation mean that the low sensitivity of predominantly alpine plants compared with that of lowland plants is attributable to their different genetic constitution, possibly as a result of selective pressure and/or de alpine species have a greater capacity to develop protective mechanisms? Pairs and triplets of species belonging to the same genus but occuring at different site elevations were grown from seeds in a greenhouse that is, without UV-B. In order to determine their capacity to adapt to UV-B radiation, some of the plants were additionally exposed to UV-B for 5-6 weeks prior to sensitivity testing. Sensitivity was tested by exposing the plants to additional UV-B of different intensities in test chambers. Visible damage, ranging from light bronzing or yellowing to withering, served as an assessment criterion. Levels of UV-B absorbing substances (phenylpropane species, usually flavonoids) were also measured in these plants. The results obtained permit the following conclusions: The greater UV-B resistance of alpine species compared with that of lowland species of the same genus is not attributable to their genetic constitution but rather to their superior adaptability. Superior resistance is in part due to a greater accumulation of UV-B absorbing substances. Distinct differences in sensitivity between different genera could lead to population shifts within ecosystems as a result of increased UV-B radiation. (orig./KW) [de

  3. PHYSIOLOGY OF ION TRANSPORT ACROSS THE TONOPLAST OF HIGHER PLANTS.

    Science.gov (United States)

    Barkla, Bronwyn J.; Pantoja, Omar

    1996-06-01

    The vacuole of plant cells plays an important role in the homeostasis of the cell. It is involved in the regulation of cytoplasmic pH, sequestration of toxic ions and xenobiotics, regulation of cell turgor, storage of amino acids, sugars and CO2 in the form of malate, and possibly as a source for elevating cytoplasmic calcium. All these activities are driven by two primary active transport mechanisms present in the vacuolar membrane (tonoplast). These two mechanisms employ high-energy metabolites to pump protons into the vacuole, establishing a proton electrochemical potential that mediates the transport of a diverse range of solutes. Within the past few years, great advances at the molecular and functional levels have been made on the characterization and identification of these mechanisms. The aim of this review is to summarize these studies in the context of the physiology of the plant cell.

  4. An expanding universe of circadian networks in higher plants.

    Science.gov (United States)

    Pruneda-Paz, Jose L; Kay, Steve A

    2010-05-01

    Extensive circadian clock networks regulate almost every biological process in plants. Clock-controlled physiological responses are coupled with daily oscillations in environmental conditions resulting in enhanced fitness and growth vigor. Identification of core clock components and their associated molecular interactions has established the basic network architecture of plant clocks, which consists of multiple interlocked feedback loops. A hierarchical structure of transcriptional feedback overlaid with regulated protein turnover sets the pace of the clock and ultimately drives all clock-controlled processes. Although originally described as linear entities, increasing evidence suggests that many signaling pathways can act as both inputs and outputs within the overall network. Future studies will determine the molecular mechanisms involved in these complex regulatory loops. 2010 Elsevier Ltd. All rights reserved.

  5. Identification and functional characterization of a flax UDP-glycosyltransferase glucosylating secoisolariciresinol (SECO) into secoisolariciresinol monoglucoside (SMG) and diglucoside (SDG).

    Science.gov (United States)

    Ghose, Kaushik; Selvaraj, Kumarakurubaran; McCallum, Jason; Kirby, Chris W; Sweeney-Nixon, Marva; Cloutier, Sylvie J; Deyholos, Michael; Datla, Raju; Fofana, Bourlaye

    2014-03-28

    Lignans are a class of diphenolic nonsteroidal phytoestrogens often found glycosylated in planta. Flax seeds are a rich source of secoisolariciresinol diglucoside (SDG) lignans. Glycosylation is a process by which a glycosyl group is covalently attached to an aglycone substrate and is catalyzed by uridine diphosphate glycosyltransferases (UGTs). Until now, very little information was available on UGT genes that may play a role in flax SDG biosynthesis. Here we report on the identification, structural and functional characterization of 5 putative UGTs potentially involved in secoisolariciresinol (SECO) glucosylation in flax. Five UGT genes belonging to the glycosyltransferases' family 1 (EC 2.4.x.y) were cloned and characterized. They fall under four UGT families corresponding to five sub-families referred to as UGT74S1, UGT74T1, UGT89B3, UGT94H1, UGT712B1 that all display the characteristic plant secondary product glycosyltransferase (PSPG) conserved motif. However, diversity was observed within this 44 amino acid sequence, especially in the two peptide sequences WAPQV and HCGWNS known to play a key role in the recognition and binding of diverse aglycone substrates and in the sugar donor specificity. In developing flax seeds, UGT74S1 and UGT94H1 showed a coordinated gene expression with that of pinoresinol-lariciresinol reductase (PLR) and their gene expression patterns correlated with SDG biosynthesis. Enzyme assays of the five heterologously expressed UGTs identified UGT74S1 as the only one using SECO as substrate, forming SECO monoglucoside (SMG) and then SDG in a sequential manner. We have cloned and characterized five flax UGTs and provided evidence that UGT74S1 uses SECO as substrate to form SDG in vitro. This study allowed us to propose a model for the missing step in SDG lignan biosynthesis.

  6. Comparative studies on the photosynthesis of higher plants, 4

    International Nuclear Information System (INIS)

    Imai, Hideo; Iwai, Sumio; Yamada, Yoshio.

    1975-01-01

    In this paper, studies were carried out to confirm whether carbon atoms except C-4 of C 4 -compounds were involved in the photosynthetic sugar formation in C 4 plants. In feeding of uniformly-labeled malate to maize leaves, sugar formation under aerobic conditions was 3 times as large as that under anaerobic conditions. There was no detectable difference in the amount of activity in the sugar formed from β-carboxyl-labeled malate between aerobic and anaerobic conditions; however. Under anaerobic conditions, sugar was formed from alanine-1- 14 C in maize but not in rice leaves. Sugar formation of this case might have occurred by the direct conversion of pyruvate to sugar via PEP and PGA. From these results, we assume that the following three pathways function cooperatively in the photosynthetic sugar formation in C 4 -plants. 1) One carbon atom at number 4 in C 4 -dicarboxylic acid is transferred to RuDP, resulting in the formation of PGA and this is metabolized into sugar. 2) After transferring C-4 of C 4 -dicarboxylic acid, the remaining C 3 -compound is introduced into the TCA cycle and completely degradated there, and thus-produced CO 2 is refixed by PEP carboxylase in the mesophyll and metabolized into sugar the same pathway as in atmospheric CO 2 fixation. 3) The remaining C 3 -compound is directly converted to PEP and then to sugar via PGA. (auth.)

  7. Mechanistic studies of ethylene biosynthesis in higher plants

    International Nuclear Information System (INIS)

    McGeehan, G.M.

    1986-01-01

    Ethylene is a plant hormone that elicits a wide variety of responses in plant tissue. Among these responses are the hastening of abscission, ripening and senescence. In 1979 it was discovered that 1-amino-1-cyclopropane carboxylic acid is the immediate biosynthetic precursor to ethylene. Given the obvious economic significance of ethylene production the authors concentrated their studies on the conversion of ACC to ethylene. They delved into mechanistic aspects of ACC oxidation and they studied potential inhibitors of ethylene forming enzyme (EFE). They synthesized various analogs of ACC and found that EFE shows good stereodiscrimination among alkyl substituted ACC analogs with the 1R, 2S stereoisomer being processed nine times faster than the 1S, 2R isomer in the MeACC series. They also synthesized 2-cyclopropyl ACC which is a good competitive inhibitor of EFE. This compound also causes time dependent loss of EFE activity leading us to believe it is an irreversible inhibitor of ethylene formation. The synthesis of these analogs has also allowed them to develop a spectroscopic technique to assign the relative stereochemistry of alkyl groups. 13 C NMR allows them to assign the alkyl stereochemistry based upon gamma-shielding effects on the carbonyl resonance. Lastly, they measured kinetic isotope effects on the oxidation of ACC in vivo and in vitro and found that ACC is oxidized by a rate-determining 1-electron removal from nitrogen in close accord with mechanisms for the oxidation of other alkyl amines

  8. CBL-CIPK network for calcium signaling in higher plants

    Science.gov (United States)

    Luan, Sheng

    Plants sense their environment by signaling mechanisms involving calcium. Calcium signals are encoded by a complex set of parameters and decoded by a large number of proteins including the more recently discovered CBL-CIPK network. The calcium-binding CBL proteins specifi-cally interact with a family of protein kinases CIPKs and regulate the activity and subcellular localization of these kinases, leading to the modification of kinase substrates. This represents a paradigm shift as compared to a calcium signaling mechanism from yeast and animals. One example of CBL-CIPK signaling pathways is the low-potassium response of Arabidopsis roots. When grown in low-K medium, plants develop stronger K-uptake capacity adapting to the low-K condition. Recent studies show that the increased K-uptake is caused by activation of a specific K-channel by the CBL-CIPK network. A working model for this regulatory pathway will be discussed in the context of calcium coding and decoding processes.

  9. Conserved upstream open reading frames in higher plants

    Directory of Open Access Journals (Sweden)

    Schultz Carolyn J

    2008-07-01

    Full Text Available Abstract Background Upstream open reading frames (uORFs can down-regulate the translation of the main open reading frame (mORF through two broad mechanisms: ribosomal stalling and reducing reinitiation efficiency. In distantly related plants, such as rice and Arabidopsis, it has been found that conserved uORFs are rare in these transcriptomes with approximately 100 loci. It is unclear how prevalent conserved uORFs are in closely related plants. Results We used a homology-based approach to identify conserved uORFs in five cereals (monocots that could potentially regulate translation. Our approach used a modified reciprocal best hit method to identify putative orthologous sequences that were then analysed by a comparative R-nomics program called uORFSCAN to find conserved uORFs. Conclusion This research identified new genes that may be controlled at the level of translation by conserved uORFs. We report that conserved uORFs are rare (

  10. Transgenic tobacco plants having a higher level of methionine are more sensitive to oxidative stress.

    Science.gov (United States)

    Hacham, Yael; Matityahu, Ifat; Amir, Rachel

    2017-07-01

    Methionine is an essential amino acid the low level of which limits the nutritional quality of plants. We formerly produced transgenic tobacco (Nicotiana tabacum) plants overexpressing CYSTATHIONE γ-SYNTHASE (CGS) (FA plants), methionine's main regulatory enzyme. These plants accumulate significantly higher levels of methionine compared with wild-type (WT) plants. The aim of this study was to gain more knowledge about the effect of higher methionine content on the metabolic profile of vegetative tissue and on the morphological and physiological phenotypes. FA plants exhibit slightly reduced growth, and metabolic profiling analysis shows that they have higher contents of stress-related metabolites. Despite this, FA plants were more sensitive to short- and long-term oxidative stresses. In addition, compared with WT plants and transgenic plants expressing an empty vector, the primary metabolic profile of FA was altered less during oxidative stress. Based on morphological and metabolic phenotypes, we strongly proposed that FA plants having higher levels of methionine suffer from stress under non-stress conditions. This might be one of the reasons for their lesser ability to cope with oxidative stress when it appeared. The observation that their metabolic profiling is much less responsive to stress compared with control plants indicates that the delta changes in metabolite contents between non-stress and stress conditions is important for enabling the plants to cope with stress conditions. © 2017 Scandinavian Plant Physiology Society.

  11. Glycosyltransferases and non-alcoholic fatty liver disease

    Science.gov (United States)

    Zhan, Yu-Tao; Su, Hai-Ying; An, Wei

    2016-01-01

    Non-alcoholic fatty liver disease (NAFLD) is the most common form of chronic liver disease and its incidence is increasing worldwide. However, the underlying mechanisms leading to the development of NAFLD are still not fully understood. Glycosyltransferases (GTs) are a diverse class of enzymes involved in catalyzing the transfer of one or multiple sugar residues to a wide range of acceptor molecules. GTs mediate a wide range of functions from structure and storage to signaling, and play a key role in many fundamental biological processes. Therefore, it is anticipated that GTs have a role in the pathogenesis of NAFLD. In this article, we present an overview of the basic information on NAFLD, particularly GTs and glycosylation modification of certain molecules and their association with NAFLD pathogenesis. In addition, the effects and mechanisms of some GTs in the development of NAFLD are summarized. PMID:26937136

  12. Functional Characterization of a Flavonoid Glycosyltransferase in Sweet Orange (Citrus sinensis).

    Science.gov (United States)

    Liu, Xiaogang; Lin, Cailing; Ma, Xiaodi; Tan, Yan; Wang, Jiuzhao; Zeng, Ming

    2018-01-01

    Fruits of sweet orange ( Citrus sinensis ), a popular commercial Citrus species, contain high concentrations of flavonoids beneficial to human health. These fruits predominantly accumulate O -glycosylated flavonoids, in which the disaccharides [neohesperidose (rhamnosyl-α-1,2-glucose) or rutinose (rhamnosyl-α-1,6-glucose)] are linked to the flavonoid aglycones through the 3- or 7-hydroxyl sites. The biotransformation of the flavonoid aglycones into O -rutinosides or O -neohesperidosides in the Citrus plants usually consists of two glycosylation reactions involving a series of uridine diphosphate-sugar dependent glycosyltransferases (UGTs). Although several genes encoding flavonoid UGTs have been functionally characterized in the Citrus plants, full elucidation of the flavonoid glycosylation process remains elusive. Based on the available genomic and transcriptome data, we isolated a UGT with a high expression level in the sweet orange fruits that possibly encodes a flavonoid glucosyltransferase and/or rhamnosyltransferase. Biochemical analyses revealed that a broad range of flavonoid substrates could be glucosylated at their 3- and/or 7-hydrogen sites by the recombinant enzyme, including hesperetin, naringenin, diosmetin, quercetin, and kaempferol. Furthermore, overexpression of the gene could significantly increase the accumulations of quercetin 7- O -rhamnoside, quercetin 7- O -glucoside, and kaempferol 7- O -glucoside, implying that the enzyme has flavonoid 7- O -glucosyltransferase and 7- O -rhamnosyltransferase activities in vivo .

  13. A web-based resource for the Arabidopsis P450, cytochromes b5, NADPH-cytochrome P450 reductases, and family 1 glycosyltransferases (http://www.P450.kvl.dk).

    Science.gov (United States)

    Paquette, Suzanne M; Jensen, Kenneth; Bak, Søren

    2009-12-01

    Gene and genome duplication is a key driving force in evolution of plant diversity. This has resulted in a number of large multi-gene families. Two of the largest multi-gene families in plants are the cytochromes P450 (P450s) and family 1 glycosyltransferases (UGTs). These two families are key players in evolution, especially of plant secondary metabolism, and in adaption to abiotic and biotic stress. In the model plant Arabidopsis thaliana there are 246 and 112 cytochromes P450 and UGTs, respectively. The Arabidopsis P450, cytochromes b(5), NADPH-cytochrome P450 reductases, and family 1 glycosyltransferases website (http://www.P450.kvl.dk) is a sequence repository of manually curated sequences, multiple sequence alignments, phylogenetic trees, sequence motif logos, 3D structures, intron-exon maps, and customized BLAST datasets.

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

    Directory of Open Access Journals (Sweden)

    Silje A. Wolff

    2014-05-01

    Full Text Available 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.

  15. Phylogenomic analysis of UDP glycosyltransferase 1 multigene family in Linum usitatissimum identified genes with varied expression patterns

    Science.gov (United States)

    2012-01-01

    Background The glycosylation process, catalyzed by ubiquitous glycosyltransferase (GT) family enzymes, is a prevalent modification of plant secondary metabolites that regulates various functions such as hormone homeostasis, detoxification of xenobiotics and biosynthesis and storage of secondary metabolites. Flax (Linum usitatissimum L.) is a commercially grown oilseed crop, important because of its essential fatty acids and health promoting lignans. Identification and characterization of UDP glycosyltransferase (UGT) genes from flax could provide valuable basic information about this important gene family and help to explain the seed specific glycosylated metabolite accumulation and other processes in plants. Plant genome sequencing projects are useful to discover complexity within this gene family and also pave way for the development of functional genomics approaches. Results Taking advantage of the newly assembled draft genome sequence of flax, we identified 137 UDP glycosyltransferase (UGT) genes from flax using a conserved signature motif. Phylogenetic analysis of these protein sequences clustered them into 14 major groups (A-N). Expression patterns of these genes were investigated using publicly available expressed sequence tag (EST), microarray data and reverse transcription quantitative real time PCR (RT-qPCR). Seventy-three per cent of these genes (100 out of 137) showed expression evidence in 15 tissues examined and indicated varied expression profiles. The RT-qPCR results of 10 selected genes were also coherent with the digital expression analysis. Interestingly, five duplicated UGT genes were identified, which showed differential expression in various tissues. Of the seven intron loss/gain positions detected, two intron positions were conserved among most of the UGTs, although a clear relationship about the evolution of these genes could not be established. Comparison of the flax UGTs with orthologs from four other sequenced dicot genomes indicated that

  16. Phylogenomic analysis of UDP glycosyltransferase 1 multigene family in Linum usitatissimum identified genes with varied expression patterns

    Directory of Open Access Journals (Sweden)

    Barvkar Vitthal T

    2012-05-01

    Full Text Available Abstract Background The glycosylation process, catalyzed by ubiquitous glycosyltransferase (GT family enzymes, is a prevalent modification of plant secondary metabolites that regulates various functions such as hormone homeostasis, detoxification of xenobiotics and biosynthesis and storage of secondary metabolites. Flax (Linum usitatissimum L. is a commercially grown oilseed crop, important because of its essential fatty acids and health promoting lignans. Identification and characterization of UDP glycosyltransferase (UGT genes from flax could provide valuable basic information about this important gene family and help to explain the seed specific glycosylated metabolite accumulation and other processes in plants. Plant genome sequencing projects are useful to discover complexity within this gene family and also pave way for the development of functional genomics approaches. Results Taking advantage of the newly assembled draft genome sequence of flax, we identified 137 UDP glycosyltransferase (UGT genes from flax using a conserved signature motif. Phylogenetic analysis of these protein sequences clustered them into 14 major groups (A-N. Expression patterns of these genes were investigated using publicly available expressed sequence tag (EST, microarray data and reverse transcription quantitative real time PCR (RT-qPCR. Seventy-three per cent of these genes (100 out of 137 showed expression evidence in 15 tissues examined and indicated varied expression profiles. The RT-qPCR results of 10 selected genes were also coherent with the digital expression analysis. Interestingly, five duplicated UGT genes were identified, which showed differential expression in various tissues. Of the seven intron loss/gain positions detected, two intron positions were conserved among most of the UGTs, although a clear relationship about the evolution of these genes could not be established. Comparison of the flax UGTs with orthologs from four other sequenced dicot

  17. Differences in glycosyltransferase family 61 accompany variation in seed coat mucilage composition in Plantago spp.

    Science.gov (United States)

    Phan, Jana L.; Tucker, Matthew R.; Khor, Shi Fang; Shirley, Neil; Lahnstein, Jelle; Beahan, Cherie; Bacic, Antony; Burton, Rachel A.

    2016-01-01

    Xylans are the most abundant non-cellulosic polysaccharide found in plant cell walls. A diverse range of xylan structures influence tissue function during growth and development. Despite the abundance of xylans in nature, details of the genes and biochemical pathways controlling their biosynthesis are lacking. In this study we have utilized natural variation within the Plantago genus to examine variation in heteroxylan composition and structure in seed coat mucilage. Compositional assays were combined with analysis of the glycosyltransferase family 61 (GT61) family during seed coat development, with the aim of identifying GT61 sequences participating in xylan backbone substitution. The results reveal natural variation in heteroxylan content and structure, particularly in P. ovata and P. cunninghamii, species which show a similar amount of heteroxylan but different backbone substitution profiles. Analysis of the GT61 family identified specific sequences co-expressed with IRREGULAR XYLEM 10 genes, which encode putative xylan synthases, revealing a close temporal association between xylan synthesis and substitution. Moreover, in P. ovata, several abundant GT61 sequences appear to lack orthologues in P. cunninghamii. Our results indicate that natural variation in Plantago species can be exploited to reveal novel details of seed coat development and polysaccharide biosynthetic pathways. PMID:27856710

  18. The Sg-1 Glycosyltransferase Locus Regulates Structural Diversity of Triterpenoid Saponins of Soybean[W][OA

    Science.gov (United States)

    Sayama, Takashi; Ono, Eiichiro; Takagi, Kyoko; Takada, Yoshitake; Horikawa, Manabu; Nakamoto, Yumi; Hirose, Aya; Sasama, Hiroko; Ohashi, Mihoko; Hasegawa, Hisakazu; Terakawa, Teruhiko; Kikuchi, Akio; Kato, Shin; Tatsuzaki, Nana; Tsukamoto, Chigen; Ishimoto, Masao

    2012-01-01

    Triterpene saponins are a diverse group of biologically functional products in plants. Saponins usually are glycosylated, which gives rise to a wide diversity of structures and functions. In the group A saponins of soybean (Glycine max), differences in the terminal sugar species located on the C-22 sugar chain of an aglycone core, soyasapogenol A, were observed to be under genetic control. Further genetic analyses and mapping revealed that the structural diversity of glycosylation was determined by multiple alleles of a single locus, Sg-1, and led to identification of a UDP-sugar–dependent glycosyltransferase gene (Glyma07g38460). Although their sequences are highly similar and both glycosylate the nonacetylated saponin A0-αg, the Sg-1a allele encodes the xylosyltransferase UGT73F4, whereas Sg-1b encodes the glucosyltransferase UGT73F2. Homology models and site-directed mutagenesis analyses showed that Ser-138 in Sg-1a and Gly-138 in Sg-1b proteins are crucial residues for their respective sugar donor specificities. Transgenic complementation tests followed by recombinant enzyme assays in vitro demonstrated that sg-10 is a loss-of-function allele of Sg-1. Considering that the terminal sugar species in the group A saponins are responsible for the strong bitterness and astringent aftertastes of soybean seeds, our findings herein provide useful tools to improve commercial properties of soybean products. PMID:22611180

  19. Plants experiencing chronic internal exposure to ionizing radiation exhibit higher frequency of homologous recombination than acutely irradiated plants

    Energy Technology Data Exchange (ETDEWEB)

    Kovalchuk, O.; Kovalchuk, I.; Hohn, B. [Friedrich Miescher Institute, P.O. Box 2543, CH-4002 Basel (Switzerland); Arkhipov, A. [Chernobyl Scientific and Technical Center of International Research, Shkolnaya Str. 6, 255620 Chernobyl (Ukraine); Barylyak, I.; Karachov, I. [Ukrainian Scientific Genetics Center, Popudrenko Str. 50, 253660 Kiev (Ukraine); Titov, V. [Ivano-Frankivsk State Medical Academy, Galitska Str.2, 284000 Ivano-Frankivsk (Ukraine)

    2000-04-03

    different chemical composition, but equal radioactivity, exhibited different levels of HR, dependent upon the absorbed dose of radiation. Remarkably, we observed a much higher frequency of HR in plants exposed to chronic irradiation when compared to acutely irradiated plants. Although acute application of 0.1-0.5 Gy did not lead to an increase of frequency of HR, the chronic exposure of the plants to several orders of magnitude lower dose of 200 {mu}Gy led to a 5-6-fold induction of the frequency of HR as compared to the control.

  20. In vitro culture of higher plants as a tool in the propagation of horticultural crops.

    NARCIS (Netherlands)

    Pierik, R.L.M.

    1988-01-01

    In vitro culture of higher plants is the culture, under sterile conditions, of plants, seeds, embryos, organs, explants, tissues, cells and protoplasts on nutrient media. This type of culture has shown spectacular development since 1975, resulting in the production and regeneration of viable

  1. Bioinformatics analysis of the predicted polyprenol reductase genes in higher plants

    Science.gov (United States)

    Basyuni, M.; Wati, R.

    2018-03-01

    The present study evaluates the bioinformatics methods to analyze twenty-four predicted polyprenol reductase genes from higher plants on GenBank as well as predicted the structure, composition, similarity, subcellular localization, and phylogenetic. The physicochemical properties of plant polyprenol showed diversity among the observed genes. The percentage of the secondary structure of plant polyprenol genes followed the ratio order of α helix > random coil > extended chain structure. The values of chloroplast but not signal peptide were too low, indicated that few chloroplast transit peptide in plant polyprenol reductase genes. The possibility of the potential transit peptide showed variation among the plant polyprenol reductase, suggested the importance of understanding the variety of peptide components of plant polyprenol genes. To clarify this finding, a phylogenetic tree was drawn. The phylogenetic tree shows several branches in the tree, suggested that plant polyprenol reductase genes grouped into divergent clusters in the tree.

  2. Molecular Evolution of the Glycosyltransferase 6 Gene Family in Primates

    Directory of Open Access Journals (Sweden)

    Eliane Evanovich

    2016-01-01

    Full Text Available Glycosyltransferase 6 gene family includes ABO, Ggta1, iGb3S, and GBGT1 genes and by three putative genes restricted to mammals, GT6m6, GTm6, and GT6m7, only the latter is found in primates. GT6 genes may encode functional and nonfunctional proteins. Ggta1 and GBGT1 genes, for instance, are pseudogenes in catarrhine primates, while iGb3S gene is only inactive in human, bonobo, and chimpanzee. Even inactivated, these genes tend to be conversed in primates. As some of the GT6 genes are related to the susceptibility or resistance to parasites, we investigated (i the selective pressure on the GT6 paralogs genes in primates; (ii the basis of the conservation of iGb3S in human, chimpanzee, and bonobo; and (iii the functional potential of the GBGT1 and GT6m7 in catarrhines. We observed that the purifying selection is prevalent and these genes have a low diversity, though ABO and Ggta1 genes have some sites under positive selection. GT6m7, a putative gene associated with aggressive periodontitis, may have regulatory function, but experimental studies are needed to assess its function. The evolutionary conservation of iGb3S in humans, chimpanzee, and bonobo seems to be the result of proximity to genes with important biological functions.

  3. Glycosyltransferase family 43 is also found in early eukaryotes and has three subfamilies in Charophycean green algae.

    Directory of Open Access Journals (Sweden)

    Rahil Taujale

    Full Text Available The glycosyltransferase family 43 (GT43 has been suggested to be involved in the synthesis of xylans in plant cell walls and proteoglycans in animals. Very recently GT43 family was also found in Charophycean green algae (CGA, the closest relatives of extant land plants. Here we present evidence that non-plant and non-animal early eukaryotes such as fungi, Haptophyceae, Choanoflagellida, Ichthyosporea and Haptophyceae also have GT43-like genes, which are phylogenetically close to animal GT43 genes. By mining RNA sequencing data (RNA-Seq of selected plants, we showed that CGA have evolved three major groups of GT43 genes, one orthologous to IRX14 (IRREGULAR XYLEM14, one orthologous to IRX9/IRX9L and the third one ancestral to all land plant GT43 genes. We confirmed that land plant GT43 has two major clades A and B, while in angiosperms, clade A further evolved into three subclades and the expression and motif pattern of A3 (containing IRX9 are fairly different from the other two clades likely due to rapid evolution. Our in-depth sequence analysis contributed to our overall understanding of the early evolution of GT43 family and could serve as an example for the study of other plant cell wall-related enzyme families.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

  6. A tandem array of UDP-glycosyltransferases from the UGT73C subfamily glycosylate sapogenins, forming a spectrum of mono- and bisdesmosidic saponins.

    Science.gov (United States)

    Erthmann, Pernille Østerbye; Agerbirk, Niels; Bak, Søren

    2018-05-01

    This study identifies six UGT73Cs all able to glucosylate sapogenins at positions 3 and/or 28 which demonstrates that B. vulgaris has a much richer arsenal of UGTs involved in saponin biosynthesis than initially anticipated. The wild cruciferous plant Barbarea vulgaris is resistant to some insects due to accumulation of two monodesmosidic triterpenoid saponins, oleanolic acid 3-O-β-cellobioside and hederagenin 3-O-β-cellobioside. Insect resistance depends on the structure of the sapogenin aglycone and the glycosylation pattern. The B. vulgaris saponin profile is complex with at least 49 saponin-like metabolites, derived from eight sapogenins and including up to five monosaccharide units. Two B. vulgaris UDP-glycosyltransferases, UGT73C11 and UGT73C13, O-glucosylate sapogenins at positions 3 and 28, forming mainly 3-O-β-D-glucosides. The aim of this study was to identify UGTs responsible for the diverse saponin oligoglycoside moieties observed in B. vulgaris. Twenty UGT genes from the insect resistant genotype were selected and heterologously expressed in Nicotiana benthamiana and/or Escherichia coli. The extracts were screened for their ability to glycosylate sapogenins (oleanolic acid, hederagenin), the hormone 24-epibrassinolide and sapogenin monoglucosides (hederagenin and oleanolic acid 3-O-β-D-glucosides). Six UGTs from the UGT73C subfamily were able to glucosylate both sapogenins and both monoglucosides at positions 3 and/or 28. Some UGTs formed bisdesmosidic saponins efficiently. At least four UGT73C genes were localized in a tandem array with UGT73C11 and possibly UGT73C13. This organization most likely reflects duplication events followed by sub- and neofunctionalization. Indeed, signs of positive selection on several amino acid sites were identified and modelled to be localized on the UGT protein surface. This tandem array is proposed to initiate higher order bisdesmosidic glycosylation of B. vulgaris saponins, leading to the recently discovered

  7. Research and higher education background of the Paks Nuclear Power Plant, Hungary. Past and present

    International Nuclear Information System (INIS)

    Csom, Gy.

    2002-01-01

    The connection of the Paks Nuclear Power Plant, Hungary, with research and development as well as with higher education is discussed. The main research areas include reactor physics, thermohydraulics, radiochemistry and radiochemical analysis, electronics and nuclear instruments, computers, materials science. The evolution of relations with higher education in Hungary and the PNPP is presented, before and after the installation of the various units. (R.P.)

  8. Role of algae and higher aquatic plants in decontamination of cyanide-containing waters

    International Nuclear Information System (INIS)

    Timofeeva, S.S.; Kraeva, V.Z.; Men'shikova, O.A.

    1986-01-01

    Cyanide compounds and especially free cyanides stand out among components of wastewaters of hydrometallurgy, electroforming, and other such enterprises with respect to toxicity and danger for man and fauna of water bodies. In this article data on a study of the regularities of decontamination of cyanide-containing wastewaters by hydrophytes are given, the mechanisms of this process are examined, and the results of testing the hydrobotanical method of treating wastewaters of a goldrecovery plant are examined. The experiments were carried out with hydrophytes from the Angara River, Lake Baikal, and small lakes and ponds in the vicinity of Irkutsk and Tashkent. The series of experiments established that algae and higher aquatic plants are resistant to cyanides. A table shows the kinetic parameters of the removal of cyanide by algae and higher aquatic plants collected in Baikal. Of the multitude of species investigated for detoxifying ability, the most resistant were detected in the experimental basins and the most suitable were charophytes

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

    Science.gov (United States)

    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.

  10. Phototolerance of lichens, mosses and higher plants in an alpine environment: analysis of photoreactions.

    Science.gov (United States)

    Heber, U; Bilger, W; Bligny, R; Lange, O L

    2000-11-01

    Adaptation to excessive light is one of the requirements of survival in an alpine environment particularly for poikilohydric organisms which in contrast to the leaves of higher plants tolerate full dehydration. Changes in modulated chlorophyll fluorescence and 820-nm absorption were investigated in the lichens Xanthoria elegans (Link) Th. Fr. and Rhizocarpon geographicum (L.) DC, in the moss Grimmia alpestris Limpr. and the higher plants Geum montanum L., Gentiana lutea L. and Pisum sativum L., all collected at altitudes higher than 2000 m above sea level. In the dehydrated state, chlorophyll fluorescence was very low in the lichens and the moss, but high in the higher plants. It increased on rehydration in the lichens and the moss, but decreased in the higher plants. Light-induced charge separation in photosystem II was indicated by pulse-induced fluorescence increases only in dried leaves, not in the dry moss and dry lichens. Strong illumination caused photodamage in the dried leaves, but not in the dry moss and dry lichens. Light-dependent increases in 820-nm absorption revealed formation of potential quenchers of chlorophyll fluorescence in all dehydrated plants, but energy transfer to quenchers decreased chlorophyll fluorescence only in the moss and the lichens, not in the higher plants. In hydrated systems, coupled cyclic electron transport is suggested to occur concurrently with linear electron transport under strong actinic illumination particularly in the lichens because far more electrons became available after actinic illumination for the reduction of photo-oxidized P700 than were available in the pool of electron carriers between photosystems II and I. In the moss Grimmia, but not in the lichens or in leaves, light-dependent quenching of chlorophyll fluorescence was extensive even under nitrogen, indicating anaerobic thylakoid acidification by persistent cyclic electron transport. In the absence of actinic illumination, acidification by ca. 8% CO2 in

  11. Reassessment of acarbose as a transition state analogue inhibitor of cyclodextrin glycosyltransferase

    NARCIS (Netherlands)

    Mosi, Renee; Sham, Howard; Uitdehaag, Joost C.M.; Ruiterkamp, Richard; Dijkstra, Bauke W.; Withers, Stephen G.

    1998-01-01

    The binding of several different active site mutants of Bacillus circulans cyclodextrin,glycosyltransferase to the inhibitor acarbose has been investigated through measurement of Ki values. The mutations represent several key amino acid positions, most of which are believed to play important roles

  12. Bacterial origin of a diverse family of UDP-glycosyltransferase genes in the Tetranychus urticae genome

    NARCIS (Netherlands)

    Ahn, S.J.; Dermauw, W.; Wybouw, N.; Heckel, D.G.; Van Leeuwen, T.

    2014-01-01

    UDP-glycosyltransferases (UGTs) catalyze the conjugation of a variety of small lipophilic molecules with uridine diphosphate (UDP) sugars, altering them into more water-soluble metabolites. Thereby, UGTs play an important role in the detoxification of xenobiotics and in the regulation of

  13. Classification, Naming and Evolutionary History of Glycosyltransferases from Sequenced Green and Red Algal Genomes

    DEFF Research Database (Denmark)

    Ulvskov, Peter; Paiva, Dionisio Soares; Domozych, David

    2013-01-01

    . In order to elucidate possible evolutionary links between the three advanced lineages in Archaeplastida, a genomic analysis was initiated. Fully sequenced genomes from the Rhodophyta and Virideplantae and the well-defined CAZy database on glycosyltransferases were included in the analysis. The number...

  14. Plant species richness sustains higher trophic levels of soil nematode communities after consecutive environmental perturbations.

    Science.gov (United States)

    Cesarz, Simone; Ciobanu, Marcel; Wright, Alexandra J; Ebeling, Anne; Vogel, Anja; Weisser, Wolfgang W; Eisenhauer, Nico

    2017-07-01

    The magnitude and frequency of extreme weather events are predicted to increase in the future due to ongoing climate change. In particular, floods and droughts resulting from climate change are thought to alter the ecosystem functions and stability. However, knowledge of the effects of these weather events on soil fauna is scarce, although they are key towards functioning of terrestrial ecosystems. Plant species richness has been shown to affect the stability of ecosystem functions and food webs. Here, we used the occurrence of a natural flood in a biodiversity grassland experiment that was followed by a simulated summer drought experiment, to investigate the interactive effects of plant species richness, a natural flood, and a subsequent summer drought on nematode communities. Three and five months after the natural flooding, effects of flooding severity were still detectable in the belowground system. We found that flooding severity decreased soil nematode food-web structure (loss of K-strategists) and the abundance of plant feeding nematodes. However, high plant species richness maintained higher diversity and abundance of higher trophic levels compared to monocultures throughout the flood. The subsequent summer drought seemed to be of lower importance but reversed negative flooding effects in some cases. This probably occurred because the studied grassland system is well adapted to drought, or because drought conditions alleviated the negative impact of long-term soil waterlogging. Using soil nematodes as indicator taxa, this study suggests that high plant species richness can maintain soil food web complexity after consecutive environmental perturbations.

  15. Research on mutation generation in higher plants with heavy ions at NIRS-HIMAC

    International Nuclear Information System (INIS)

    Okamura, M.; Watanabe, S.; Watanabe, M.; Toguri, T.; Furusawa, Y.

    2006-01-01

    Plants are closely related to medical treatment in medicine, foods, herbs and medical care by gardening. Ion beams have much higher linear energy transfer (LET) and relative biological effectiveness than those of gamma rays and X-rays. Ion beams are supposed to be useful as new mutagen to obtain novel mutants with superior characteristics in higher plants. In this study, the influence of heavy ions irradiation on bud growth was examined in carnation and the mutation generation was inspected in babies' breath. The growth of carnation buds began to decrease at 10 Gy and the median growth dose was estimated at 35 Gy for 290 Mev/u carbon ion beams. Mutants with petaloid leaves were observed in babies' breath by the irradiation of 290 Mev/u carbon ion beams at 20Gy. We will examine the mutation rates and spectrum for 290 MeV/u carbon, 400 MeV/u neon and 500 MeV/u argon ion beams to find optimum use of the beams in plant breeding. The efficient system to generate useful mutants using heavy ions at NIRS-HIMAC will be developed in higher plants. (author)

  16. Higher plants and UV-B radiation: balancing damage, repair and acclimation

    International Nuclear Information System (INIS)

    Jansen, M.A.K.; Gaba, V.; Greenberg, B.M.

    1998-01-01

    Although UV-B is a minor component of sunlight, it has a disproportionately damaging effect on higher plants. Ultraviolet-sensitive targets include DNA, proteins and membranes, and these must be protected for normal growth and development. DNA repair and secondary metabolite accumulation during exposure to UV-B have been characterized in considerable detail, but little is known about the recovery of photosynthesis, induction of free-radical scavenging and morphogenic changes. A future challenge is to elucidate how UV-B-exposed plants balance damage, repair, acclimation and adaptation responses in a photobiologically dynamic environment. (author)

  17. Cadmium against higher plant photosynthesis - a variety of effects and where do they possibly come from?

    International Nuclear Information System (INIS)

    Krupa, Z.

    1999-01-01

    The complexity of in vivo toxic effects of Cd on higher plants makes almost impossible an accurate distinction between direct and indirect mechanisms of its action on the photosynthetic apparatus. We, therefore, postulate that multiple Cd effects on plant physiological and metabolic processes may finally be focused on photosynthesis. This would also explain the phenomenon that only a small fraction of Cd entering chloroplasts may cause such disastrous changes in their structure and function. In return, the inhibition of photosynthesis affects numerous metabolic pathways dependent on the primary carbon metabolism. (orig.)

  18. The complete mitochondrial genome of Gossypium hirsutum and evolutionary analysis of higher plant mitochondrial genomes.

    Science.gov (United States)

    Liu, Guozheng; Cao, Dandan; Li, Shuangshuang; Su, Aiguo; Geng, Jianing; Grover, Corrinne E; Hu, Songnian; Hua, Jinping

    2013-01-01

    Mitochondria are the main manufacturers of cellular ATP in eukaryotes. The plant mitochondrial genome contains large number of foreign DNA and repeated sequences undergone frequently intramolecular recombination. Upland Cotton (Gossypium hirsutum L.) is one of the main natural fiber crops and also an important oil-producing plant in the world. Sequencing of the cotton mitochondrial (mt) genome could be helpful for the evolution research of plant mt genomes. We utilized 454 technology for sequencing and combined with Fosmid library of the Gossypium hirsutum mt genome screening and positive clones sequencing and conducted a series of evolutionary analysis on Cycas taitungensis and 24 angiosperms mt genomes. After data assembling and contigs joining, the complete mitochondrial genome sequence of G. hirsutum was obtained. The completed G.hirsutum mt genome is 621,884 bp in length, and contained 68 genes, including 35 protein genes, four rRNA genes and 29 tRNA genes. Five gene clusters are found conserved in all plant mt genomes; one and four clusters are specifically conserved in monocots and dicots, respectively. Homologous sequences are distributed along the plant mt genomes and species closely related share the most homologous sequences. For species that have both mt and chloroplast genome sequences available, we checked the location of cp-like migration and found several fragments closely linked with mitochondrial genes. The G. hirsutum mt genome possesses most of the common characters of higher plant mt genomes. The existence of syntenic gene clusters, as well as the conservation of some intergenic sequences and genic content among the plant mt genomes suggest that evolution of mt genomes is consistent with plant taxonomy but independent among different species.

  19. Importance of molybdenum in the nitrogen metabolism of microorganisms and higher plants

    Energy Technology Data Exchange (ETDEWEB)

    Mulder, E G

    1948-01-01

    The effect of molybdenum on the growth of microorganisms and higher plants and on some well-defined biochemical reactions was investigated. Results indicate that Aspergillus niger requires small amounts of molybdenum when growing in a culture solution supplied with nitrate nitrogen. With ammonium sulfate as a source of nitrogen, the response of the fungus to molybdenum was much smaller. It was shown that this different response of Aspergillus to molybdenum was not brought about by a difference in purity of both nitrogen compounds used, nor by a difference in absorption of the molybdenum impurity, but by a considerably higher requirement of molybdenum in a medium with nitrate nitrogen. The growth-rate curve and the increasing sporulation of Aspergillus niger with increasing amounts of molybdenum were used in estimating very small amounts of this element in various materials. In culture solution experiments with tomato, barley and oat plants the effect of traces of molybdenum on the growth of these plants was investigated. In good agreement with the results of the experiments with Aspergillus and denitrifying bacteria it could be shown that in the green plant as in these microorganisms molybdenum is acting as a catalyst in nitrate reduction. In experiments with Azotobacter chroococcum and leguminous plants the effect of molybdenum on the fixation of gaseous N/sub 2/ was studied. In culture solutions with pea plants the effect of molybdenum on the nitrogen fixation of the nodules was investigated. In the absence of molybdenum as well as in a complete nutrient medium many nodules were formed. 30 references, 6 figures, 16 tables.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

  2. Identification of a root-specific glycosyltransferase from Arabidopsis ...

    Indian Academy of Sciences (India)

    SEARCH U

    antimicrobial or pesticidal proteins in certain tissues of the plant which are the sites ... interest for engineering resistance against root nematodes. (Huang et al .... animals and plants to identify and study genes based on their expression pattern ...

  3. Evolutionary history and stress regulation of the lectin superfamily in higher plants

    Directory of Open Access Journals (Sweden)

    Ramachandran Srinivasan

    2010-03-01

    Full Text Available Abstract Background Lectins are a class of carbohydrate-binding proteins. They play roles in various biological processes. However, little is known about their evolutionary history and their functions in plant stress regulation. The availability of full genome sequences from various plant species makes it possible to perform a whole-genome exploration for further understanding their biological functions. Results Higher plant genomes encode large numbers of lectin proteins. Based on their domain structures and phylogenetic analyses, a new classification system has been proposed. In this system, 12 different families have been classified and four of them consist of recently identified plant lectin members. Further analyses show that some of lectin families exhibit species-specific expansion and rapid birth-and-death evolution. Tandem and segmental duplications have been regarded as the major mechanisms to drive lectin expansion although retrogenes also significantly contributed to the birth of new lectin genes in soybean and rice. Evidence shows that lectin genes have been involved in biotic/abiotic stress regulations and tandem/segmental duplications may be regarded as drivers for plants to adapt various environmental stresses through duplication followed by expression divergence. Each member of this gene superfamily may play specialized roles in a specific stress condition and function as a regulator of various environmental factors such as cold, drought and high salinity as well as biotic stresses. Conclusions Our studies provide a new outline of the plant lectin gene superfamily and advance the understanding of plant lectin genes in lineage-specific expansion and their functions in biotic/abiotic stress-related developmental processes.

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

    Science.gov (United States)

    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.

  5. The Arabidopsis UDP-glycosyltransferases UGT79B2 and UGT79B3, contribute to cold, salt and drought stress tolerance via modulating anthocyanin accumulation.

    Science.gov (United States)

    Li, Pan; Li, Yan-Jie; Zhang, Feng-Ju; Zhang, Gui-Zhi; Jiang, Xiao-Yi; Yu, Hui-Min; Hou, Bing-Kai

    2017-01-01

    The plant family 1 UDP-glycosyltransferases (UGTs) are the biggest GT family in plants, which are responsible for transferring sugar moieties onto a variety of small molecules, and control many metabolic processes; however, their physiological significance in planta is largely unknown. Here, we revealed that two Arabidopsis glycosyltransferase genes, UGT79B2 and UGT79B3, could be strongly induced by various abiotic stresses, including cold, salt and drought stresses. Overexpression of UGT79B2/B3 significantly enhanced plant tolerance to low temperatures as well as drought and salt stresses, whereas the ugt79b2/b3 double mutants generated by RNAi (RNA interference) and CRISPR-Cas9 strategies were more susceptible to adverse conditions. Interestingly, the expression of UGT79B2 and UGT79B3 is directly controlled by CBF1 (CRT/DRE-binding factor 1, also named DREB1B) in response to low temperatures. Furthermore, we identified the enzyme activities of UGT79B2/B3 in adding UDP-rhamnose to cyanidin and cyanidin 3-O-glucoside. Ectopic expression of UGT79B2/B3 significantly increased the anthocyanin accumulation, and enhanced the antioxidant activity in coping with abiotic stresses, whereas the ugt79b2/b3 double mutants showed reduced anthocyanin levels. When overexpressing UGT79B2/B3 in tt18 (transparent testa 18), a mutant that cannot synthesize anthocyanins, both genes fail to improve plant adaptation to stress. Taken together, we demonstrate that UGT79B2 and UGT79B3, identified as anthocyanin rhamnosyltransferases, are regulated by CBF1 and confer abiotic stress tolerance via modulating anthocyanin accumulation. © 2016 The Authors The Plant Journal © 2016 John Wiley & Sons Ltd.

  6. How common is ecological speciation in plant-feeding insects? A 'Higher' Nematinae perspective

    Directory of Open Access Journals (Sweden)

    Nyman Tommi

    2010-09-01

    Full Text Available Abstract Background Ecological speciation is a process in which a transiently resource-polymorphic species divides into two specialized sister lineages as a result of divergent selection pressures caused by the use of multiple niches or environments. Ecology-based speciation has been studied intensively in plant-feeding insects, in which both sympatric and allopatric shifts onto novel host plants could speed up diversification. However, while numerous examples of species pairs likely to have originated by resource shifts have been found, the overall importance of ecological speciation in relation to other, non-ecological speciation modes remains unknown. Here, we apply phylogenetic information on sawflies belonging to the 'Higher' Nematinae (Hymenoptera: Tenthredinidae to infer the frequency of niche shifts in relation to speciation events. Results Phylogenetic trees reconstructed on the basis of DNA sequence data show that the diversification of higher nematines has involved frequent shifts in larval feeding habits and in the use of plant taxa. However, the inferred number of resource shifts is considerably lower than the number of past speciation events, indicating that the majority of divergences have occurred by non-ecological allopatric speciation; based on a time-corrected analysis of sister species, we estimate that a maximum of c. 20% of lineage splits have been triggered by a change in resource use. In addition, we find that postspeciational changes in geographic distributions have led to broad sympatry in many species having identical host-plant ranges. Conclusion Our analysis indicates that the importance of niche shifts for the diversification of herbivorous insects is at present implicitly and explicitly overestimated. In the case of the Higher Nematinae, employing a time correction for sister-species comparisons lowered the proportion of apparent ecology-based speciation events from c. 50-60% to around 20%, but such corrections are

  7. Atomistic insight into the catalytic mechanism of glycosyltransferases by combined quantum mechanics/molecular mechanics (QM/MM) methods.

    Science.gov (United States)

    Tvaroška, Igor

    2015-02-11

    Glycosyltransferases catalyze the formation of glycosidic bonds by assisting the transfer of a sugar residue from donors to specific acceptor molecules. Although structural and kinetic data have provided insight into mechanistic strategies employed by these enzymes, molecular modeling studies are essential for the understanding of glycosyltransferase catalyzed reactions at the atomistic level. For such modeling, combined quantum mechanics/molecular mechanics (QM/MM) methods have emerged as crucial. These methods allow the modeling of enzymatic reactions by using quantum mechanical methods for the calculation of the electronic structure of the active site models and treating the remaining enzyme environment by faster molecular mechanics methods. Herein, the application of QM/MM methods to glycosyltransferase catalyzed reactions is reviewed, and the insight from modeling of glycosyl transfer into the mechanisms and transition states structures of both inverting and retaining glycosyltransferases are discussed. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. The three transglycosylation reactions catalyzed by cyclodextrin glycosyltransferase from Bacillus circulans (strain 251) proceed via different kinetic mechanisms

    NARCIS (Netherlands)

    Veen, Bart A. van der; Alebeek, Gert-Jan W.M. van; Uitdehaag, Joost C.M.; Dijkstra, Bauke W.; Dijkhuizen, Lubbert

    Cyclodextrin glycosyltransferase (CGTase) catalyzes three transglycosylation reactions via a double displacement mechanism involving a covalent enzyme-intermediate complex (substituted-enzyme intermediate). Characterization of the three transglycosylation reactions, however, revealed that they

  9. Phytate (Inositol Hexakisphosphate in Soil and Phosphate Acquisition from Inositol Phosphates by Higher Plants. A Review

    Directory of Open Access Journals (Sweden)

    Jörg Gerke

    2015-05-01

    Full Text Available Phosphate (P fixation to the soil solid phase is considered to be important for P availability and is often attributed to the strong binding of orthophosphate anion species. However, the fixation and subsequent immobilization of inositolhexa and pentaphosphate isomers (phytate in soil is often much stronger than that of the orthosphate anion species. The result is that phytate is a main organic P form in soil and the dominating form of identifiable organic P. The reasons for the accumulation are not fully clear. Two hypothesis can be found in the literature in the last 20 years, the low activity of phytase (phosphatases in soil, which makes phytate P unavailable to the plant roots, and, on the other hand, the strong binding of phytate to the soil solid phase with its consequent stabilization and accumulation in soil. The hypothesis that low phytase activity is responsible for phytate accumulation led to the development of genetically modified plant genotypes with a higher expression of phytase activity at the root surface and research on the effect of a higher phytate activity on P acquisition. Obviously, this hypothesis has a basic assumption, that the phytate mobility in soil is not the limiting step for P acquisition of higher plants from soil phytate. This assumption is, however, not justified considering the results on the sorption, immobilization and fixation of phytate to the soil solid phase reported in the last two decades. Phytate is strongly bound, and the P sorption maximum and probably the sorption strength of phytate P to the soil solid phase is much higher, compared to that of orthophosphate P. Mobilization of phytate seems to be a promising step to make it available to the plant roots. The excretion of organic acid anions, citrate and to a lesser extend oxalate, seems to be an important way to make phytate P available to the plants. Phytase activity at the root surface seems not be the limiting step in P acquisition from phytate

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  13. Glycosyltransferase Gene Expression Profiles Classify Cancer Types and Propose Prognostic Subtypes

    Science.gov (United States)

    Ashkani, Jahanshah; Naidoo, Kevin J.

    2016-05-01

    Aberrant glycosylation in tumours stem from altered glycosyltransferase (GT) gene expression but can the expression profiles of these signature genes be used to classify cancer types and lead to cancer subtype discovery? The differential structural changes to cellular glycan structures are predominantly regulated by the expression patterns of GT genes and are a hallmark of neoplastic cell metamorphoses. We found that the expression of 210 GT genes taken from 1893 cancer patient samples in The Cancer Genome Atlas (TCGA) microarray data are able to classify six cancers; breast, ovarian, glioblastoma, kidney, colon and lung. The GT gene expression profiles are used to develop cancer classifiers and propose subtypes. The subclassification of breast cancer solid tumour samples illustrates the discovery of subgroups from GT genes that match well against basal-like and HER2-enriched subtypes and correlates to clinical, mutation and survival data. This cancer type glycosyltransferase gene signature finding provides foundational evidence for the centrality of glycosylation in cancer.

  14. Preliminary X-ray crystallographic analysis of the glycosyltransferase from a marine Streptomyces species

    International Nuclear Information System (INIS)

    Gong, Liping; Xiao, Yi; Liu, Qiang; Li, Sumei; Zhang, Changsheng; Liu, Jinsong

    2010-01-01

    The recombinant glycosyltransferase ElaGT from the elaiophylin-producing marine Streptomyces sp. SCSIO 01934 has been overexpressed in E. coli, purified and crystallized. Diffraction data were collected to 2.9 Å resolution. ElaGT is a glycosyltransferase from a marine Streptomyces species that is involved in the biosynthesis of elaiophylin. Here, the molecular cloning, protein expression and purification, preliminary crystallization and crystallographic characterization of ElaGT are reported. The rod-shaped crystals belonged to space group P2 1 22, with unit-cell parameters a = 66.7, b = 131.7, c = 224.6 Å, α = 90, β = 90, γ = 90°. Data were collected to 2.9 Å resolution. A preliminary molecular-replacement solution implied the presence of two ElaGT molecules in the asymmetric unit

  15. Interference of Cd2+ in functioning of the photosynthetic apparatus of higher plants

    Directory of Open Access Journals (Sweden)

    Tadeusz Baszyński

    2014-01-01

    Full Text Available The actual opinions concerning the role of Cd2+ in inhibition of photosynthesis have been reviewed. The light phase of photosynthesis, particularly the site of Cd2+ action in the photosynthetic transport chain has been given the greatest attention. Cd2+-induced inhibition of Photosystem II activity as the result of thylakoid membrane degradation has been discussed. The present studies on Cd2+-inhibited dark reactions occurring in stroma has been analysed. Attention has been drawn to the fact that the results of studies in vitro are not always compatible with the changes found in the photosynthetic apparatus of higher plants growing in a Cd2 containing medium.

  16. Consequences of variation in plant defense for biodiversity at higher trophic levels

    NARCIS (Netherlands)

    Poelman, E.H.; Loon, van J.J.A.; Dicke, M.

    2008-01-01

    Antagonistic interactions between insect herbivores and plants impose selection on plants to defend themselves against these attackers. Although selection on plant defense traits has typically been studied for pairwise plant¿attacker interactions, other community members of plant-based food webs are

  17. Biochemical studies on the effect of fluoride on higher plants. II. The effect of fluoride on sucrose-synthesizing enzymes from higher plants

    Energy Technology Data Exchange (ETDEWEB)

    Yang, S F; Miller, G W

    1963-01-01

    A study was initiated to characterize the properties of partially purified phosphoglucomutase, uridine diphosphate glucose pyrophosphorylase and uridine diphosphate glucose-fructose transglucosyalse, from various plant sources, with respect to activation by metal ions and inhibition by fluoride. Of the three enzymes studied, only phosphoglucomutase was very sensitive to fluoride. It is likely that the inhibition of sucrose synthesis in fluoride-fumigated plants might be due to the inhibition of phosphoglucomutase, which plays an important role in carbohydrate metabolism. However, at present, there is insufficient evidence to show the inhibition of phosphoglucomutase in vivo by fumigation with hydrogen fluoride.

  18. Fate of induced mutations in higher plants with special emphasis on sexually reproducing species

    International Nuclear Information System (INIS)

    Cornu, Andre

    1978-01-01

    A mutation induced in a plant somatic cell has to overcome quite many difficulties before being isolated and utilized as a marker in a mutated line. If induced in a meristem, three conditions must be fulfilled for the mutation to be transmitted to the subsequent generation: it must be compatible with normal cell multiplication, it must be located in a cell mass that will provide an inflorescence, and it must be in the sporogenetic layer (t2). Under these conditions, or if it is induced in a gamete or in a zygote, the mutation enters a first cycle of sexual reproduction. Meiosis and the subsequent haploid phase constitute severe screening steps for many chromosome aberrations. Studies on Petunia performed by means of marker genes show that male and female gametic viabilities are drastically impaired by deletions. However, a deficient chromosome can be transmitted when the losss of information is compensated for by homologous information as, for example, diploid gametes from tetraploids or disomic gametes resulting from non-disjunction. If partial or complete sterility, whether sporo- or gametophytic, is avoided, then the mutation can be transmitted to the next generation in heterozygous state. When becoming homozygous, the mutation may have effects such that its use can be most difficult. This is the case when this mutation causes rather early lethality or severe sterility. Thus, in higher plants, one faces several cases of powerful and efficient selection against mutations. On the basis of experiments carried out on Petunia, the per locus mutation rate of practical interest ranges between I and 5/10000M 1 plants. Practical conclusions are drawn about which organ should be treated, which mutagen at what dose should be used according to the scope of the research undertaken [fr

  19. Plasmodesmata without callose and calreticulin in higher plants - open channels for fast symplastic transport?

    Directory of Open Access Journals (Sweden)

    Kirill N. Demchenko

    2014-03-01

    Full Text Available Plasmodesmata (PD represent membrane-lined channels that link adjacent plant cells across the cell wall. PD of higher plants contain a central tube of endoplasmic reticulum called desmotubule. Membrane and lumen proteins seem to be able to move through the desmotubule, but most transport processes through PD occur through the cytoplasmic annulus (Brunkard et al., 2013. Calreticulin (CRT, a highly conserved Ca2+-binding protein found in all multi-cellular eukaryotes, predominantly located in the ER, was shown to localize to PD, though not all PD accumulate CRT. In nitrogen fixing actinorhizal root nodules of the Australian tree Casuarina glauca, the primary walls of infected cells containing the microsymbiont become lignified upon infection. TEM analysis of these nodules showed that during the differentiation of infected cells, PD connecting infected cells, and connecting infected and adjacent uninfected cells, were reduced in number as well as diameter (Schubert et al., 2013. In contrast with PD connecting young infected cells, and most PD connecting mature infected and adjacent uninfected cells, PD connecting mature infected cells did not accumulate CRT. Furthermore, as shown here, these PD were not associated with callose, and based on their diameter, they probably had lost their desmotubules. We speculate that either this is a slow path to PD degradation, or that the loss of callose accumulation and presumably also desmotubules leads to the PD becoming open channels and improves metabolite exchange between cells.

  20. Effects of fluoride on mitochondrial activity in higher plants. [Glycine max, Zea mays

    Energy Technology Data Exchange (ETDEWEB)

    Miller, J E; Miller, G W

    1974-01-01

    The effects of fluoride on respiration of plant tissue and mitochondria were investigated. Fumigation of young soybean plants (Glycine max Merr. cm. Hawkeye) with 9-12 ..mu..g x m/sup -3/ HF caused a stimulation of respiration at about 2 days of treatment followed by inhibition 2 days later. Mitochondria isolated from the stimulated tissue had higher respiration rates, greater ATPase activity, and lower P/O ratios, while in mitochondria from inhibited tissue, all three were reduced. Treatment of etiolated soybean hypocotyl sections in Hoagland's solution containing KF for 3 to 10 h only resulted in inhibition of respiration. Mitochondria isolated from this tissue elicited increased respiration rates with malate as substrate and inhibited respiration with succinate. With both substrates respiratory control and ADP/O ratios were decreased. Direct treatment of mitochondria from etiolated soybean hypocotyl tissue with fluoride resulted in inhibition of state 3 respiration and lower ADP/O ratios with the substrates succinate, malate, and NADH. Fluoride was also found to increase the amount of osmotically induced swelling and cause a more rapid leakage of protein with mitochondria isolated from etiolated corn shoots (Zea mays L. cv. Golden Cross Bantam). 40 references, 1 figure, 5 tables.

  1. The use of sulphite solutions for studying the effects of SO2 on higher plants

    International Nuclear Information System (INIS)

    Garsed, S.G.

    1981-01-01

    The effects of sulphite concentration and pH on 14 CO 2 fixation or the uptake of 35 S by needle segments of Pinus sylvestris were studied in factorial experiments. In addition, changes in the chemical composition of the sulphite solutions during the experiment were measured. Uptake of 14 CO 2 was increased and standard errors decreased by incorporating 1.0 to 10 ppm of Tween 80 into the solutions used. Inhibition of 14 CO 2 fixation by sulphite was significantly greater at low pH and high sulphite concentration, with a significant interaction. Uptake of Na 2 35 SO 3 was greater at low pH and was linear with respect to the concentration of Na 2 SO 3 carrier added between 10 -3 and 10 -4 M. In the absence of carrier, recovery of 35 S at the end of the experiment was reduced. Oxidation of the sulphite solutions was rapid at high pH and low concentration, with a significant interaction. It was also accelerated by the presence of plant material. The use of sulphite solutions to predict responses of higher plants to SO 2 is discussed. (author)

  2. Studies on the application of radiation for genetic transformation in higher plants

    International Nuclear Information System (INIS)

    Lee, Young Il; Song, Hi Sup; Kim, Jae Sung; Shin, In Chul; Lee, Sang Jae; Lee, Ki Woon; Lim, Yong Taek

    1992-02-01

    Present research carried out to develop the radiation application on the mutation research of genetic engineering. Some variants selected in M1 generation derived from the plantlet by the nodal stem culture of three potato cultivars irradiated with gamma rays, and the optimum dosage for mutation induction was revealed the range of 30 - 50 Gy of gamma ray. In the rice anther culture of the plant irradiated with gamma rays at different developmental stage of microspore, the haploidy callus formation rates were much higher in gamma ray irradiated anthers than those of non-irradiated, and the occurrence of a typical pollen was significantly increased up to 47% in the anthers irradiated with 30 Gy of gamma ray compared with 11% of non-irradiated anthers at the stage of pollen mother cell. A lot of variants were selected in rice, soybean, perilla and red pepper irradiated with gamma rays for breeding of earliness, short culm, high yielding and disease resistant mutant. (Author)

  3. Electric current precedes emergence of a lateral root in higher plants.

    Science.gov (United States)

    Hamada, S; Ezaki, S; Hayashi, K; Toko, K; Yamafuji, K

    1992-10-01

    Stable electrochemical patterns appear spontaneously around roots of higher plants and are closely related to growth. An electric potential pattern accompanied by lateral root emergence was measured along the surface of the primary root of adzuki bean (Phaseolus angularis) over 21 h using a microelectrode manipulated by a newly developed apparatus. The electric potential became lower at the point where a lateral root emerged. This change preceded the emergence of the lateral root by about 10 h. A theory is presented for calculating two-dimensional patterns of electric potential and electric current density around the primary root (and a lateral root) using only data on the one-dimensional electric potential measured near the surface of the primary root. The development of the lateral root inside the primary root is associated with the influx of electric current of about 0.7 muA.cm(-2) at the surface.

  4. Structure of the higher plant light harvesting complex I: In vivo characterization and structural interdependence of the Lhca proteins

    NARCIS (Netherlands)

    Klimmek, F.; Ganeteg, U.; Ihalainen, J.A.; van Roon, H.; Jensen, P.E.; Scheller, H.V.; Dekker, J.P.; Jansson, S.

    2005-01-01

    We have investigated the structure of the higher plant light harvesting complex of photosystem I (LHCI) by analyzing PSI-LHCI particles isolated from a set of Arabidopsis plant lines, each lacking a specific Lhca (Lhca1-4) polypeptide. Functional antenna size measurements support the recent finding

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

    Science.gov (United States)

    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.

  6. Optimization of animal manure vermicomposting based on biomass production of earthworms and higher plants.

    Science.gov (United States)

    Borges, Yan V; Alves, Luciano; Bianchi, Ivan; Espíndola, Jonas C; Oliveira, Juahil M De; Radetski, Claudemir M; Somensi, Cleder A

    2017-11-02

    The goal of this study was to optimize the mixture of swine manure (SM) and cattle manure (CM) used in the vermicomposting process, seeking to increase the manure biodegradation rate and enhance the biomass production of both earthworms and higher plants. To achieve this goal, physico-chemical parameters were determined to assess the final compost quality after 50 days of vermicomposting. The different manure ratios used to produce the composts (C) were as follows (SM:CM, % m/m basis): C1 100:0, C2 (75:25), C3 (50:50), C4 (25:75), and C5 (0:100). In addition, the earthworm biomass and the phytoproductivity of lettuce (Lactuca sativa L.) plants grown in mixtures (1:1) of natural soil and the most viable vermicomposts were investigated. The C1 and C2 compost compositions were associated with high earthworm mortality rates. The C3 compost provided the highest mineral concentrations and C5 showed the highest lettuce yield (wet biomass). The results verify that stabilized cattle manure is an excellent substrate for the vermicomposting process and that fresh swine manure must be mixed with pre-stabilized cattle manure to ensure an optimized vermicomposting process, which must be controlled in terms of temperature and ammonia levels. It is concluded that small livestock farmers could add value to swine manure by applying the vermicomposting process, without the need for high investments and with a minimal requirement for management of the biodegradation process. These are important technical aspects to be considered when circular economy principles are applied to small farms.

  7. The invasive wetland plant Alternanthera philoxeroides shows a higher tolerance to waterlogging than its native Congener Alternanthera sessilis.

    Directory of Open Access Journals (Sweden)

    Yue Chen

    Full Text Available Plant invasion is one of the major threats to natural ecosystems. Phenotypic plasticity is considered to be important for promoting plant invasiveness. High tolerance of stress can also increase survival of invasive plants in adverse habitats. Limited growth and conservation of carbohydrate are considered to increase tolerance of flooding in plants. However, few studies have examined whether invasive species shows a higher phenotypic plasticity in response to waterlogging or a higher tolerance of waterlogging (lower plasticity than native species. We conducted a greenhouse experiment to compare the growth and morphological and physiological responses to waterlogging of the invasive, clonal, wetland species Alternanthera philoxeroides with those of its co-occurring, native, congeneric, clonal species Alternanthera sessilis. Plants of A. philoxeroides and A. sessilis were subjected to three treatments (control, 0 and 60 cm waterlogging. Both A. philoxeroides and A. sessilis survived all treatments. Overall growth was lower in A. philoxeroides than in A. sessilis, but waterlogging negatively affected the growth of A. philoxeroides less strongly than that of A. sessilis. Alternanthera philoxeroides thus showed less sensitivity of growth traits (lower plasticity and higher waterlogging tolerance. Moreover, the photosynthetic capacity of A. philoxeroides was higher than that of A. sessilis during waterlogging. Alternanthera philoxeroides also had higher total non-structural and non-soluble carbohydrate concentrations than A. sessilis at the end of treatments. Our results suggest that higher tolerance to waterlogging and higher photosynthetic capacity may partly explain the invasion success of A. philoxeroides in wetlands.

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

    NARCIS (Netherlands)

    Pashalidou, F.G.; Frago, E.; Griese, E.; Poelman, E.H.; Loon, van J.J.A.; Dicke, M.; Fatouros, N.E.

    2015-01-01

    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

  9. Analysis of the Arabidopsis IRX9/IRX9-L and IRX14/IRX14-L pairs of glycosyltransferase genes reveals critical contributions to biosynthesis of the hemicellulose glucuronoxylan.

    Science.gov (United States)

    Wu, Ai-Min; Hörnblad, Emma; Voxeur, Aline; Gerber, Lorenz; Rihouey, Christophe; Lerouge, Patrice; Marchant, Alan

    2010-06-01

    The hemicellulose glucuronoxylan (GX) is a major component of plant secondary cell walls. However, our understanding of GX synthesis remains limited. Here, we identify and analyze two new genes from Arabidopsis (Arabidopsis thaliana), IRREGULAR XYLEM9-LIKE (IRX9-L) and IRX14-LIKE (IRX14-L) that encode glycosyltransferase family 43 members proposed to function during xylan backbone elongation. We place IRX9-L and IRX14-L in a genetic framework with six previously described glycosyltransferase genes (IRX9, IRX10, IRX10-L, IRX14, FRAGILE FIBER8 [FRA8], and FRA8 HOMOLOG [F8H]) and investigate their function in GX synthesis. Double-mutant analysis identifies IRX9-L and IRX14-L as functional homologs of IRX9 and IRX14, respectively. Characterization of irx9 irx10 irx14 fra8 and irx9-L irx10-L irx14-L f8h quadruple mutants allows definition of a set of genes comprising IRX9, IRX10, IRX14, and FRA8 that perform the main role in GX synthesis during vegetative development. The IRX9-L, IRX10-L, IRX14-L, and F8H genes are able to partially substitute for their respective homologs and normally perform a minor function. The irx14 irx14-L double mutant virtually lacks xylan, whereas irx9 irx9-L and fra8 f8h double mutants form lowered amounts of GX displaying a greatly reduced degree of backbone polymerization. Our findings reveal two distinct sets of four genes each differentially contributing to GX biosynthesis.

  10. Utilization of the higher plants in a study on hereditary effect of low-dose irradiation

    International Nuclear Information System (INIS)

    Yamashita, Jun

    1976-01-01

    Some problems in a study of hereditary effect of low-dose irradiation, which used the higher plants (tradescantia, peas, etc.) as materials, were mentioned. Conditions to be used as materials were mentioned as follows: 1) the materials must have high radio-sensitivity, 2) the natural mutation of the materials must be low, 3) hereditary uniformity and stability of genes in the materials were important, and 4) in case of considering the materials as environmental radiation monitors, the observation period must be long and the duration from exposure to detection of mutation must be short. Tradescantia has most of these conditions, but the greatest fault is that the object of its observation is mutation of somatic cells, and hereditary study is impossible. Therefore, it is necessary to find out other materials in order to solve the problem whether there is a difference in relative frequency of chromosomal abnormalities, which occurrs in germinal cells and is transmitted to posterity, between low and high doses or not. (Serizawa, K.)

  11. SIGNIFICANCE OF GALACTINOL AND RAFFINOSE FAMILY OLIGOSACCHARIDE SYNTHESIS IN PLANTS

    Directory of Open Access Journals (Sweden)

    Sonali eSengupta

    2015-08-01

    Full Text Available Abiotic stress induces differential expression of genes responsible for the synthesis of Raffinose series of Oligosaccharides (RFOs in plants. RFOs are described as the most widespread D-galactose containing oligosaccharides in higher plants. Biosynthesis of RFOs begin with the activity of Galactinol synthase (GolS; EC 2.4.1.123, a GT8 family glycosyltransferase that galactosylates myo-inositol to produce galactinol. Raffinose and the subsequent higher molecular weight RFOs (Stachyose, Verbascose and Ajugose are synthesized from sucrose by the subsequent addition of activated galactose moieties donated by Galactinol. Interestingly, GolS, the key enzyme of this pathway is functional only in the flowering plants. It is thus assumed that RFO synthesis is a specialized metabolic event in higher plants; although it is not known whether lower plant groups synthesize any galactinol or RFOs. In higher plants, several functional importance of RFOs have been reported, e.g. RFOs protect the embryo from maturation associated desiccation, are predominant transport carbohydrate in some plant families, act as signaling molecule following pathogen attack and wounding and accumulate in vegetative tissues in response to a range of abiotic stresses. However, the loss-of-function mutants reported so far fail to show any perturbation in those biological functions. The role of RFOs in biotic and abiotic stress is therefore still in debateand their specificity and related components remains to be demonstrated. The present review discusses the biology and stress-linked regulation of this less studied extension of inositol metabolic pathway.

  12. Formation of flavone di-O-glucosides using a glycosyltransferase from Bacillus cereus.

    Science.gov (United States)

    Ahn, Byoung Chan; Kim, Bong Gyu; Jeon, Young Min; Lee, Eun Jeong; Lim, Yoongho; Ahn, Joong-Hoon

    2009-04-01

    Microbial UDP-glycosyltransferases can convert many small lipophilic compounds into glycons using uridinediphosphate- activated sugars. The glycosylation of flavonoids affects solubility, stability, and bioavailability. The gene encoding the UDP-glycosyltransferase from Bacillus cereus, BcGT-3, was cloned by PCR and sequenced. BcGT-3 was expressed in Escherichia coli BL21 (DE3) with a glutathione S-transferase tag and purified using a glutathione Stransferase affinity column. BcGT-3 was tested for activity on several substrates including genistein, kaempferol, luteolin, naringenin, and quercetin. Flavonols were the best substrates for BcGT-3. The enzyme dominantly glycosylated the 3-hydroxyl group, but the 7-hydroxyl group was glycosylated when the 3-hydroxyl group was not available. The kaempferol reaction products were identified as kaempferol-3-O-glucoside and kaempferol- 3,7-O-diglucoside. Kaempferol was the most effective substrate tested. Based on HPLC, LC/MS, and NMR analyses of the reaction products, we conclude that BcGT-3 can be used for the synthesis of kaempferol 3,7-O-diglucose.

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

    Science.gov (United States)

    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.

  14. Hygiene evaluation of the air conditions in the Lower Main region by means of higher and lower plants

    Energy Technology Data Exchange (ETDEWEB)

    Steubing, L; Klee, R; Kirschbaum, U

    1974-06-01

    By using the distribution patterns of natural growths of epiphytic lichens, three lichen zones can be distinguished in the Lower Main region of FRG. Each zone corresponds to different degrees of injury to lichens, and each zone is characterized by a particular pollutant load. Damage to plants is functionally correlated with the destruction of chlorophyll. Primary production, dust covering, sulfur content and conductivity of higher plants in two of the lichen zones confirm the data from test stations.

  15. The re-assimilation of ammonia produced by photorespiration and the nitrogen economy of C3 higher plants.

    Science.gov (United States)

    Keys, Alfred J

    2006-02-01

    Photorespiration involves the conversion of glycine to serine with the release of ammonia and CO(2). In C(3) terrestrial higher plants the flux through glycine and serine is so large that it results in the production of ammonia at a rate far exceeding that from reduction of new nitrogen entering the plant. The photorespiratory nitrogen cycle re-assimilates this ammonia using the enzymes glutamine synthetase and glutamine:2-oxoglutarateaminotransferase.

  16. Stepwise catalytic mechanism via short-lived intermediate inferred from combined QM/MM MERP and PES calculations on retaining glycosyltransferase ppGalNAcT2.

    Science.gov (United States)

    Trnka, Tomáš; Kozmon, Stanislav; Tvaroška, Igor; Koča, Jaroslav

    2015-04-01

    The glycosylation of cell surface proteins plays a crucial role in a multitude of biological processes, such as cell adhesion and recognition. To understand the process of protein glycosylation, the reaction mechanisms of the participating enzymes need to be known. However, the reaction mechanism of retaining glycosyltransferases has not yet been sufficiently explained. Here we investigated the catalytic mechanism of human isoform 2 of the retaining glycosyltransferase polypeptide UDP-GalNAc transferase by coupling two different QM/MM-based approaches, namely a potential energy surface scan in two distance difference dimensions and a minimum energy reaction path optimisation using the Nudged Elastic Band method. Potential energy scan studies often suffer from inadequate sampling of reactive processes due to a predefined scan coordinate system. At the same time, path optimisation methods enable the sampling of a virtually unlimited number of dimensions, but their results cannot be unambiguously interpreted without knowledge of the potential energy surface. By combining these methods, we have been able to eliminate the most significant sources of potential errors inherent to each of these approaches. The structural model is based on the crystal structure of human isoform 2. In the QM/MM method, the QM region consists of 275 atoms, the remaining 5776 atoms were in the MM region. We found that ppGalNAcT2 catalyzes a same-face nucleophilic substitution with internal return (SNi). The optimized transition state for the reaction is 13.8 kcal/mol higher in energy than the reactant while the energy of the product complex is 6.7 kcal/mol lower. During the process of nucleophilic attack, a proton is synchronously transferred to the leaving phosphate. The presence of a short-lived metastable oxocarbenium intermediate is likely, as indicated by the reaction energy profiles obtained using high-level density functionals.

  17. Stepwise catalytic mechanism via short-lived intermediate inferred from combined QM/MM MERP and PES calculations on retaining glycosyltransferase ppGalNAcT2.

    Directory of Open Access Journals (Sweden)

    Tomáš Trnka

    2015-04-01

    Full Text Available The glycosylation of cell surface proteins plays a crucial role in a multitude of biological processes, such as cell adhesion and recognition. To understand the process of protein glycosylation, the reaction mechanisms of the participating enzymes need to be known. However, the reaction mechanism of retaining glycosyltransferases has not yet been sufficiently explained. Here we investigated the catalytic mechanism of human isoform 2 of the retaining glycosyltransferase polypeptide UDP-GalNAc transferase by coupling two different QM/MM-based approaches, namely a potential energy surface scan in two distance difference dimensions and a minimum energy reaction path optimisation using the Nudged Elastic Band method. Potential energy scan studies often suffer from inadequate sampling of reactive processes due to a predefined scan coordinate system. At the same time, path optimisation methods enable the sampling of a virtually unlimited number of dimensions, but their results cannot be unambiguously interpreted without knowledge of the potential energy surface. By combining these methods, we have been able to eliminate the most significant sources of potential errors inherent to each of these approaches. The structural model is based on the crystal structure of human isoform 2. In the QM/MM method, the QM region consists of 275 atoms, the remaining 5776 atoms were in the MM region. We found that ppGalNAcT2 catalyzes a same-face nucleophilic substitution with internal return (SNi. The optimized transition state for the reaction is 13.8 kcal/mol higher in energy than the reactant while the energy of the product complex is 6.7 kcal/mol lower. During the process of nucleophilic attack, a proton is synchronously transferred to the leaving phosphate. The presence of a short-lived metastable oxocarbenium intermediate is likely, as indicated by the reaction energy profiles obtained using high-level density functionals.

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

    Science.gov (United States)

    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.

  19. CEZ utility's coal-fired power plants: towards a higher environmental friendliness

    International Nuclear Information System (INIS)

    Kindl, V.; Spilkova, T.; Vanousek, I.; Stehlik, J.

    1996-01-01

    Environmental efforts of the major Czech utility, CEZ a.s., are aimed at reducing air pollution arising from electricity and heat generating facilities. There are 3 main kinds of activity in this respect: phasing out of coal fired power plants; technological provisions to reduce emissions of particulate matter, sulfur dioxide, and nitrogen oxides from those coal fired units that are to remain in operation after 1998; and completion of the Temelin nuclear power plant. In 1995, emissions of particulate matter, sulfur dioxide, nitrogen oxides, and carbon monoxide from CEZ's coal fired power plants were 19%, 79%, 59%, and 60%, respectively, with respect to the situation in 1992. The break-down of electricity generation by CEZ facilities (in GWh) was as follows in 1995: hydroelectric power plants 1673, nuclear power plants 12230, coal fired power plants without desulfurization equipment 30181, and coal fired power plants with desulfurization equipment 2277. Provisions implemented to improve the environmental friendliness of the individual CEZ's coal fired power plants are described in detail. (P.A.). 5 tabs., 1 fig

  20. The Arabidopsis Family GT43 Glycosyltransferases Form Two Functionally Nonredundant Groups Essential for the Elongation of Glucuronoxylan Backbone

    Science.gov (United States)

    There exist four members of family GT43 glycosyltransferases in the Arabidopsis (Arabidopsis thaliana) genome, and mutations of two of them, IRX9 and IRX14, have previously been shown to cause a defect in glucuronoxylan (GX) biosynthesis. However, it is currently unknown whether ...

  1. [Sugar Chain Construction of Functional Natural Products Using Plant Glucosyltransferases].

    Science.gov (United States)

    Mizukami, Hajime

    2015-01-01

    Plant secondary product glycosyltransferases belong to family 1 of the glycosyltransferase superfamily and mediate the transfer of a glycosyl residue from activated nucleotide sugars to lipophilic small molecules, thus affecting the solubility, stability and pharmacological activities of the sugar-accepting compounds. The biotechnological application of plant glycosyltransferases in glycoside synthesis has attracted attention because enzymatic glycosylation offers several advantages over chemical methods, including (1) avoiding the use of harsh conditions and toxic catalysts, (2) providing strict control of regio-and stereo-selectivity and (3) high efficiency. This review describes the in vivo and in vitro glycosylation of natural organic compounds using glycosyltransferases, focusing on our investigation of enzymatic synthesis of curcumin glycosides. Our current efforts toward functional characterization of some glycosyltransferases involved in the biosynthesis of iridoids and crocin, as well as in the sugar chain elongation of quercetin glucosides, are described. Finally, I describe the relationship of the structure of sugar chains and the intestinal absorption which was investigated using chemoenzymatically synthesized quercetin glycosides.

  2. Acquisition and Homeostasis of Iron in Higher Plants and Their Probable Role in Abiotic Stress Tolerance

    Directory of Open Access Journals (Sweden)

    Durgesh K. Tripathi

    2018-02-01

    Full Text Available Iron (Fe is a micronutrient that plays an important role in agriculture worldwide because plants require a small amount of iron for its growth and development. All major functions in a plant's life from chlorophyll biosynthesis to energy transfer are performed by Fe (Brumbarova et al., 2008; Gill and Tuteja, 2011. Iron also acts as a major constituent of many plant proteins and enzymes. The acquisition of Fe in plants occurs through two strategies, i.e., strategy I and strategy II (Marschner and Römheld, 1994. Under various stress conditions, Nramp and the YSL gene families help in translocation of Fe, which further acts as a mineral regulatory element and defends plants against stresses. Iron plays an irreplaceable role in alleviating stress imposed by salinity, drought, and heavy metal stress. This is because it activates plant enzymatic antioxidants like catalase (CAT, peroxidase, and an isoform of superoxide dismutase (SOD that act as a scavenger of reactive oxygen species (ROS (Hellin et al., 1995. In addition to this, their deficiency as well as their excess amount can disturb the homeostasis of a plant's cell and result in declining of photosynthetic rate, respiration, and increased accumulation of Na+ and Ca− ions which culminate in an excessive formation of ROS. The short-range order hydrated Fe oxides and organic functional groups show affinities for metal ions. Iron plaque biofilm matrices could sequester a large amount of metals at the soil–root interface. Hence, it has attracted the attention of plant physiologists and agricultural scientists who are discovering more exciting and hidden applications of Fe and its potential in the development of bio-factories. This review looks into the recent progress made in putting forward the role of Fe in plant growth, development, and acclimation under major abiotic stresses, i.e., salinity, drought, and heavy metals.

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

    DEFF Research Database (Denmark)

    Yuan, Wenping; Liu, Shuguang; Dong, Wenjie

    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...

  4. Zinc oxide and silver nanoparticles influence the antioxidative status in a higher aquatic plant, Spirodela punctata

    CSIR Research Space (South Africa)

    Thwala, Melusi

    2012-09-01

    Full Text Available during the 14-d exposure. The biochemical anti-oxidative status of the plant specimens were investigated using quantitative analysis of total antioxidant capacity, peroxidase and activity of catalase and superoxide dismutase. The anti-oxidative defence...

  5. Metabolism of ibuprofen in higher plants: A model Arabidopsis thaliana cell suspension culture system

    Czech Academy of Sciences Publication Activity Database

    Maršík, Petr; Šíša, Miroslav; Lacina, O.; Moťková, Kateřina; Langhansová, Lenka; Rezek, Jan; Vaněk, Tomáš

    2017-01-01

    Roč. 220, JAN (2017), s. 383-392 ISSN 0269-7491 R&D Projects: GA ČR(CZ) GA14-22593S Grant - others:European Regional Development Fund(XE) CZ.2.16/3.1.00/24014 Institutional support: RVO:61389030 Keywords : Arabidopsis thaliana * Ibuprofen * Metabolism * Plant cells * Sequestration Subject RIV: CE - Biochemistry OBOR OECD: Plant sciences, botany Impact factor: 5.099, year: 2016

  6. Integration of pharmaceuticals with higher plants as a model of phytoremediation

    OpenAIRE

    Pomeislová, Alice

    2015-01-01

    The presence of pharmaceuticals in wastewater, which are not eliminated in sewage treatment plant process and thus get easily into rivers and aquatic environment in general, constitutes a severe problem to the whole society. The research into the removal of pharmaceuticals from the environment began about twenty years ago. Phytoremediation represents one of the most promising wastewater treatment methods. It is based on the ability of plants to remove xenobiotics from their environment and se...

  7. Integral use of amaranth starch to obtain cyclodextrin glycosyltransferase, by Bacillus megaterium, to produce β-cyclodextrin.

    Directory of Open Access Journals (Sweden)

    María Belem Arce-Vázquez

    2016-09-01

    Full Text Available Cyclodextrin glycosyltransferase (CGTase is an enzyme that produces cyclodextrins (CDs from starch and related carbohydrates, producing a mixture of α-, β-, and γ-CDs in different amounts. CGTase production, mainly by Bacillus sp., depends on fermentation conditions such as pH, temperature, concentration of nutrients, carbon and nitrogen sources, among others. Bacillus megaterium CGTase produces those three types of CDs, however, β-CD should prevail. Although waxy corn starch (CS is used industrially to obtain CGTase and CDs because of its high amylopectin content, alternative sources such as amaranth starch (AS could be used to accomplish those purposes. AS has high susceptibility to the amylolytic activity of CGTase because of its 80% amylopectin content. Therefore, the aim of this work was evaluate the AS as carbon source for CGTase production by B. megaterium in a submerged fermentation. Afterwards, the CGTase was purified partially and its activity to synthesize α-, β- and γ-CDs was evaluated using 1% AS as substrate. B. megaterium produced a 66 kDa CGTase (Topt=50°C; pHopt=8.0, from the early exponential growth phase which lasted 36 h. The maximum CGTase specific activity (106.62±8.33 U/mg protein was obtained after 36 h of culture. CGTase obtained with a Km=0.152 mM and a Vmax=13.4 µM/min yielded 40.47% total CDs using AS which was roughly twice as much as that of corn starch (CS; 24.48%. High costs to produce CDs in the pharmaceutical and food industries might be reduced by using AS because of its higher α-, β- and γ-CDs production (12.81%, 17.94% and 9.92%, respectively in a shorter time than that needed for CS.

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

    Science.gov (United States)

    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. © 2016 SETAC.

  9. Tomato UDP-Glucose Sterol Glycosyltransferases: A Family of Developmental and Stress Regulated Genes that Encode Cytosolic and Membrane-Associated Forms of the Enzyme

    Directory of Open Access Journals (Sweden)

    Karla Ramirez-Estrada

    2017-06-01

    Full Text Available Sterol glycosyltransferases (SGTs catalyze the glycosylation of the free hydroxyl group at C-3 position of sterols to produce sterol glycosides. Glycosylated sterols and free sterols are primarily located in cell membranes where in combination with other membrane-bound lipids play a key role in modulating their properties and functioning. In contrast to most plant species, those of the genus Solanum contain very high levels of glycosylated sterols, which in the case of tomato may account for more than 85% of the total sterol content. In this study, we report the identification and functional characterization of the four members of the tomato (Solanum lycopersicum cv. Micro-Tom SGT gene family. Expression of recombinant SlSGT proteins in E. coli cells and N. benthamiana leaves demonstrated the ability of the four enzymes to glycosylate different sterol species including cholesterol, brassicasterol, campesterol, stigmasterol, and β-sitosterol, which is consistent with the occurrence in their primary structure of the putative steroid-binding domain found in steroid UDP-glucuronosyltransferases and the UDP-sugar binding domain characteristic for a superfamily of nucleoside diphosphosugar glycosyltransferases. Subcellular localization studies based on fluorescence recovery after photobleaching and cell fractionation analyses revealed that the four tomato SGTs, like the Arabidopsis SGTs UGT80A2 and UGT80B1, localize into the cytosol and the PM, although there are clear differences in their relative distribution between these two cell fractions. The SlSGT genes have specialized but still largely overlapping expression patterns in different organs of tomato plants and throughout the different stages of fruit development and ripening. Moreover, they are differentially regulated in response to biotic and abiotic stress conditions. SlSGT4 expression increases markedly in response to osmotic, salt, and cold stress, as well as upon treatment with abscisic

  10. 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

    Science.gov (United States)

    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.

  11. Two bee-pollinated plant species show higher seed production when grown in gardens compared to arable farmland.

    Directory of Open Access Journals (Sweden)

    John Cussans

    2010-07-01

    Full Text Available Insect pollinator abundance, in particular that of bees, has been shown to be high where there is a super-abundance of floral resources; for example in association with mass-flowering crops and also in gardens where flowering plants are often densely planted. Since land management affects pollinator numbers, it is also likely to affect the resultant pollination of plants growing in these habitats. We hypothesised that the seed or fruit set of two plant species, typically pollinated by bumblebees and/or honeybees might respond in one of two ways: 1 pollination success could be reduced when growing in a floriferous environment, via competition for pollinators, or 2 pollination success could be enhanced because of increased pollinator abundance in the vicinity.We compared the pollination success of experimental plants of Glechoma hederacea L. and Lotus corniculatus L. growing in gardens and arable farmland. On the farms, the plants were placed either next to a mass-flowering crop (oilseed rape, Brassica napus L. or field beans, Vicia faba L. or next to a cereal crop (wheat, Triticum spp.. Seed set of G. hederacea and fruit set of L. corniculatus were significantly higher in gardens compared to arable farmland. There was no significant difference in pollination success of G. hederacea when grown next to different crops, but for L. corniculatus, fruit set was higher in the plants growing next to oilseed rape when the crop was in flower.The results show that pollination services can limit fruit set of wild plants in arable farmland, but there is some evidence that the presence of a flowering crop can facilitate their pollination (depending on species and season. We have also demonstrated that gardens are not only beneficial to pollinators, but also to the process of pollination.

  12. MOLECULAR-GENETIC BASIS OF HIGHER PLANTS TOLERANCE TO, AND ACCUMULATION OF, CADMIUM

    Directory of Open Access Journals (Sweden)

    Olga A Kulaeva

    2010-09-01

    Full Text Available Cadmium (Cd is one of the most wide-ranged and dangerous pollutants for all living organisms, including plants. At present time the intensive studies of mechanisms of Cd accumulation in plant tissues and plant tolerance to its toxic influence are performed. Data about variation of Cd tolerance and accumulation traits in natural populations of hyperaccumulators species as well as important crops were obtained. A series of mutants with changed sensitivity to Cd was obtained. In recent decade several classes of proteins involving in cell responses to Cd ions were revealed. An important role of microRNA in plant adaptation to Cd was recently demonstrated. Studies of molecular-genetic mechanisms of Cd accumulation and plant tolerance to it are theoretical basis for development of phytoremediation technologies of soil contaminated with heavy metals and breeding of crop varieties with decreased Cd accumulation.

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

    Science.gov (United States)

    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

    2014-06-26

    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.

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

    Science.gov (United States)

    Yuan, Wenping; Liu, Shuguang; Dong, Wenjie; Liang, Shunlin; Zhao, Shuqing; Chen, Jingming; Xu, Wenfang; Li, Xianglan; Barr, Alan; Black, T. Andrew; Yan, Wende; Goulden, Michael; 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.

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

    Science.gov (United States)

    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. © 2015 John Wiley & Sons Ltd/CNRS.

  16. Engineering plastid fatty acid biosynthesis to improve food quality and biofuel production in higher plants.

    Science.gov (United States)

    Rogalski, Marcelo; Carrer, Helaine

    2011-06-01

    The ability to manipulate plant fatty acid biosynthesis by using new biotechnological approaches has allowed the production of transgenic plants with unusual fatty acid profile and increased oil content. This review focuses on the production of very long chain polyunsaturated fatty acids (VLCPUFAs) and the increase in oil content in plants using molecular biology tools. Evidences suggest that regular consumption of food rich in VLCPUFAs has multiple positive health benefits. Alternative sources of these nutritional fatty acids are found in cold-water fishes. However, fish stocks are in severe decline because of decades of overfishing, and also fish oils can be contaminated by the accumulation of toxic compounds. Recently, there is also an increase in oilseed use for the production of biofuels. This tendency is partly associated with the rapidly rising costs of petroleum, increased concern about the environmental impact of fossil oil and the attractive need to develop renewable sources of fuel. In contrast to this scenario, oil derived from crop plants is normally contaminant free and less environmentally aggressive. Genetic engineering of the plastid genome (plastome) offers a number of attractive advantages, including high-level foreign protein expression, marker-gene excision and transgene containment because of maternal inheritance of plastid genome in most crops. Here, we describe the possibility to improve fatty acid biosynthesis in plastids, production of new fatty acids and increase their content in plants by genetic engineering of plastid fatty acid biosynthesis via plastid transformation. © 2011 The Authors. Plant Biotechnology Journal © 2011 Society for Experimental Biology, Association of Applied Biologists and Blackwell Publishing Ltd.

  17. Congruence and diversity of butterfly-host plant associations at higher taxonomic levels.

    Directory of Open Access Journals (Sweden)

    José R Ferrer-Paris

    Full Text Available 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.

  18. Congruence and diversity of butterfly-host plant associations at higher taxonomic levels.

    Science.gov (United States)

    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.

  19. Abilities of some higher plants to hydrolyze the acetates of phenols and aromatic-aliphatic alcohols

    Directory of Open Access Journals (Sweden)

    Agnieszka Mironowicz

    2014-01-01

    Full Text Available In the biotransformations carried out under the same conditions, the whole intact plants of Spirodela punctata, Nephrolepis exaltata, Cyrtomium falcatum, Nephrolepis cordifolia and the suspension cultures of Helianthus tuberosus, Daucus carota and Petunia hybrida hydrolyze (partially or totally the ester bonds of the acetates of phenols and aromatic-aliphatic alcohols and also the menthyl acetate. Nevertheless, the methyl esters of aromatic acids, structurally similar to the former substrates, do not undergo hydrolysis. At the same time, the viability of first four plants was observed for different levels of acetate concentration. The method of continuous preparative hydrolysis of the same acetates was worked out in Cyrtomium falcatum culture.

  20. Glycemic Response to Corn Starch Modified with Cyclodextrin Glycosyltransferase and its Relationship to Physical Properties.

    Science.gov (United States)

    Dura, A; Yokoyama, W; Rosell, C M

    2016-09-01

    Corn starch was modified with cyclodextrin glycosyltransferase (CGTase) below the gelatinization temperature. The porous granules with or without CGTase hydrolysis products may be used as an alternative to modified corn starches in foods applications. The amount and type of hydrolysis products were determined, containing mainly β-cyclodextrin (CD), which will influence pasting behavior and glycemic response in mice. Irregular surface and small holes were observed by microscopic analysis and differences in pasting properties were observed in the presence of hydrolysis products. Postprandial blood glucose in mice fed gelatinized enzymatically modified starch peaked earlier than their ungelatinized counterparts. However, in ungelatinized enzymatically modified starches, the presence of β- CD may inhibit the orientation of amylases slowing hydrolysis, which may help to maintain lower blood glucose levels. Significant correlations were found between glycemic curves and viscosity pattern of starches.

  1. Utilization of respiratory energy in higher plants : requirements for 'maintenance' and transport processes

    NARCIS (Netherlands)

    Bouma, T.J.

    1995-01-01

    Quantitative knowledge of both photosynthesis and respiration is required to understand plant growth and resulting crop yield. However, especially the nature of the energy demanding processes that are dependent on dark respiration in full-grown tissues is largely unknown. The main objective

  2. Zinc oxide and silver nanoparticles influence the antioxidative status in a higher aquatic plant, Spirodela punctata

    CSIR Research Space (South Africa)

    Thwala, Melusi

    2012-09-01

    Full Text Available The authors present evidence of free radical activity and resultant anti-oxidative defence in Spirodela plants after exposure to 0.01-1000 mg/L of ZnO and Ag nanoparticles (NPs) over 96-h and 14-d. The quantification of reactive nitrogen...

  3. Higher operational safety of nuclear power plants by evaluating the behaviour of operating personnel

    International Nuclear Information System (INIS)

    Mertins, M.; Glasner, P.

    1990-01-01

    In the GDR power reactors have been operated since 1966. Since that time operational experiences of 73 cumulative reactor years have been collected. The behaviour of operating personnel is an essential factor to guarantee the safety of operation of the nuclear power plant. Therefore a continuous analysis of the behaviour of operating personnel has been introduced at the GDR nuclear power plants. In the paper the overall system of the selection, preparation and control of the behaviour of nuclear power plant operating personnel is presented. The methods concerned are based on recording all errors of operating personnel and on analyzing them in order to find out the reasons. The aim of the analysis of reasons is to reduce the number of errors. By a feedback of experiences the nuclear safety of the nuclear power plant can be increased. All data necessary for the evaluation of errors are recorded and evaluated by a computer program. This method is explained thoroughly in the paper. Selected results of error analysis are presented. It is explained how the activities of the personnel are made safer by means of this analysis. Comparisons with other methods are made. (author). 3 refs, 4 figs

  4. Predicting molybdenum toxicity to higher plants: Estimation of toxicity threshold values

    Energy Technology Data Exchange (ETDEWEB)

    McGrath, S.P., E-mail: steve.mcgrath@bbsrc.ac.u [Soil Science Department, Centre for Soils and Ecosystems Function, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ (United Kingdom); Mico, C.; Zhao, F.J.; Stroud, J.L. [Soil Science Department, Centre for Soils and Ecosystems Function, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ (United Kingdom); Zhang, H.; Fozard, S. [Division of Environmental Science, Lancaster University, Lancaster LA1 4YQ (United Kingdom)

    2010-10-15

    Four plant species (oilseed rape, Brassica napus L.; red clover, Trifolium pratense L.; ryegrass, Lolium perenne L.; and tomato, Lycopersicon esculentum L.) were tested on ten soils varying widely in soil properties to assess molybdenum (Mo) toxicity. A larger range (66-fold-609-fold) of added Mo concentrations resulting in 50% inhibition of yield (ED{sub 50}) was found among soils than among plant species (2-fold-38-fold), which illustrated that the soils differed widely in the expression of Mo toxicity. Toxicity thresholds based on soil solution Mo narrowed the variation among soils compared to thresholds based on added Mo concentrations. We conclude that plant bioavailability of Mo in soil depends on Mo solubility, but this alone did not decrease the variability in observed toxicity enough to be used in risk assessment and that other soil properties influencing Mo toxicity to plants need to be considered. - Mo toxicity thresholds varied widely in different soils and therefore soil properties need to be taken into account in order to assess the risk of Mo exposure.

  5. Radioecological investigations of phytocommunities higher water plant in upper Kiev water reservoir

    International Nuclear Information System (INIS)

    Pan'kov, I.V.; Volkova, E.N.; Shirokaya, Z.O.; Karapish, V.A.; Dremlyuga, S.V.

    1997-01-01

    The dose loads of the highest water plants it determined and ecological role of phytocommunities in radionuclides distribution and migration in water reservoir is shown. The ' critical zones ' for characteristic types of phytocommunities are determined. It is marked that radionuclides accumulation by macrophits depends on species and ecological group

  6. The xanthophylls in light-harvesting complex II of higher plants: light harvesting and triplet quenching.

    NARCIS (Netherlands)

    Peterman, E.J.G.; Gradinaru, C.C.; Calkoen, F.; Borst, J.C.; van Grondelle, R.; van Amerongen, H.

    1997-01-01

    A spectral and functional assignment of the xanthophylls in monomeric and trimeric light-harvesting complex II of green plants has been obtained using HPLC analysis of the pigment composition, laser-flash induced triplet- minus-singlet, fluorescence excitation, and absorption spectra. It is shown

  7. Higher accumulation of F1-V fusion recombinant protein in plants after induction of protein body formation.

    Science.gov (United States)

    Alvarez, M Lucrecia; Topal, Emel; Martin, Federico; Cardineau, Guy A

    2010-01-01

    Improving foreign protein accumulation is crucial for enhancing the commercial success of plant-based production systems since product yields have a major influence on process economics. Cereal grain evolved to store large amounts of proteins in tightly organized aggregates. In maize, gamma-Zein is the major storage protein synthesized by the rough endoplasmic reticulum (ER) and stored in specialized organelles called protein bodies (PB). Zera (gamma-Zein ER-accumulating domain) is the N-terminal proline-rich domain of gamma-zein that is sufficient to induce the assembly of PB formation. Fusion of the Zera domain to proteins of interest results in assembly of dense PB-like, ER-derived organelles, containing high concentration of recombinant protein. Our main goal was to increase recombinant protein accumulation in plants in order to enhance the efficiency of orally-delivered plant-made vaccines. It is well known that oral vaccination requires substantially higher doses than parental formulations. As a part of a project to develop a plant-made plague vaccine, we expressed our model antigen, the Yersinia pestis F1-V antigen fusion protein, with and without a fused Zera domain. We demonstrated that Zera-F1-V protein accumulation was at least 3x higher than F1-V alone when expressed in three different host plant systems: Ncotiana benthamiana, Medicago sativa (alfalfa) and Nicotiana tabacum NT1 cells. We confirmed the feasibility of using Zera technology to induce protein body formation in non-seed tissues. Zera expression and accumulation did not affect plant development and growth. These results confirmed the potential exploitation of Zera technology to substantially increase the accumulation of value-added proteins in plants.

  8. Expression and Purification of Glycosyltransferases in Pichia Pastoris: Towards Improving the Migration of Stem Cells by Enhancing Surface Expression of Sialyl Lewis X

    KAUST Repository

    Al-Amoodi, Asma S.

    2017-01-01

    Recruitment of circulating cells towards target sites is primarily dependent on E-selectin receptor/ligand adhesive interactions. Glycosyltransferase (GTs) are involved in the creation of E-selectin ligands. A sialofucosylated terminal

  9. Specialist plant species harbour higher reproductive performances in recently restored calcareous grasslands than in reference habitats

    OpenAIRE

    Harzé, Mélanie; Mahy, Grégory; Bizoux, Jean-Philippe; Piqueray, Julien; Monty, Arnaud

    2015-01-01

    Background and aims_Calcareous grasslands are local biodiversity hotspots in temperate regions that suffered intensive fragmentation. Ecological restoration projects took place all over Europe. Their success has traditionally been assessed using a plant community approach. However, population ecology can also be useful to assess restoration success and to understand underlying mechanisms. Methods_We took advantage of three calcareous grassland sites in Southern Belgium, where reference p...

  10. Experimental studies on SO/sub 2/ injuries in higher plants. Part 4

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, H; Takanashi, T; Yatazawa, M

    1970-01-01

    The effect of sulfur dioxide on aminoacid metabolism was examined. Wheat seedlings one month old (20 cm) were exposed to 0.5 ppm SO/sub 2/ at 22/sup 0/C, and 40% humidity for four days, only during the day. A Beckman 1200 aminoacid analyzer revealed only slight effects, but it was conjectured that the plant had some separate amino acid in its body prior to the test, and that the effect of SO/sub 2/ was relatively low. A similar wheat seedling was placed in a closed glass container and was exposed to 300 ppm carbon dioxide (14) and 100 ppm SO/sub 2/ for 30 min under 4000 lux. The first paper chromatography of 80% ethanol solubles from the leaves revealed that Ala. value had increased but sir. had decreased in half. The second paper chromatography revealed that in both test and control plants, four kinds of material in amino acid had taken in C(14), and two of the four were Ser. Ala. The total C(14) taken in by the test material under SO/sub 2/ exposure showed a noted decrease. The experiment proved that exposure of a plant to a high concentration of SO/sub 2/ produced hydroxysulfonate in metabolism and impaired its glycol acid function.

  11. Progress and challenges of engineering a biophysical CO2-concentrating mechanism into higher plants.

    Science.gov (United States)

    Rae, Benjamin D; Long, Benedict M; Förster, Britta; Nguyen, Nghiem D; Velanis, Christos N; Atkinson, Nicky; Hee, Wei Yih; Mukherjee, Bratati; Price, G Dean; McCormick, Alistair J

    2017-06-01

    Growth and productivity in important crop plants is limited by the inefficiencies of the C3 photosynthetic pathway. Introducing CO2-concentrating mechanisms (CCMs) into C3 plants could overcome these limitations and lead to increased yields. Many unicellular microautotrophs, such as cyanobacteria and green algae, possess highly efficient biophysical CCMs that increase CO2 concentrations around the primary carboxylase enzyme, Rubisco, to enhance CO2 assimilation rates. Algal and cyanobacterial CCMs utilize distinct molecular components, but share several functional commonalities. Here we outline the recent progress and current challenges of engineering biophysical CCMs into C3 plants. We review the predicted requirements for a functional biophysical CCM based on current knowledge of cyanobacterial and algal CCMs, the molecular engineering tools and research pipelines required to translate our theoretical knowledge into practice, and the current challenges to achieving these goals. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  12. DNA repair and recombination in higher plants: insights from comparative genomics of arabidopsis and rice

    Directory of Open Access Journals (Sweden)

    Choudhury Swarup

    2010-07-01

    Full Text Available Abstract Background The DNA repair and recombination (DRR proteins protect organisms against genetic damage, caused by environmental agents and other genotoxic agents, by removal of DNA lesions or helping to abide them. Results We identified genes potentially involved in DRR mechanisms in Arabidopsis and rice using similarity searches and conserved domain analysis against proteins known to be involved in DRR in human, yeast and E. coli. As expected, many of DRR genes are very similar to those found in other eukaryotes. Beside these eukaryotes specific genes, several prokaryotes specific genes were also found to be well conserved in plants. In Arabidopsis, several functionally important DRR gene duplications are present, which do not occur in rice. Among DRR proteins, we found that proteins belonging to the nucleotide excision repair pathway were relatively more conserved than proteins needed for the other DRR pathways. Sub-cellular localization studies of DRR gene suggests that these proteins are mostly reside in nucleus while gene drain in between nucleus and cell organelles were also found in some cases. Conclusions The similarities and dissimilarities in between plants and other organisms' DRR pathways are discussed. The observed differences broaden our knowledge about DRR in the plants world, and raises the potential question of whether differentiated functions have evolved in some cases. These results, altogether, provide a useful framework for further experimental studies in these organisms.

  13. DNA repair and recombination in higher plants: insights from comparative genomics of Arabidopsis and rice.

    Science.gov (United States)

    Singh, Sanjay K; Roy, Sujit; Choudhury, Swarup Roy; Sengupta, Dibyendu N

    2010-07-21

    The DNA repair and recombination (DRR) proteins protect organisms against genetic damage, caused by environmental agents and other genotoxic agents, by removal of DNA lesions or helping to abide them. We identified genes potentially involved in DRR mechanisms in Arabidopsis and rice using similarity searches and conserved domain analysis against proteins known to be involved in DRR in human, yeast and E. coli. As expected, many of DRR genes are very similar to those found in other eukaryotes. Beside these eukaryotes specific genes, several prokaryotes specific genes were also found to be well conserved in plants. In Arabidopsis, several functionally important DRR gene duplications are present, which do not occur in rice. Among DRR proteins, we found that proteins belonging to the nucleotide excision repair pathway were relatively more conserved than proteins needed for the other DRR pathways. Sub-cellular localization studies of DRR gene suggests that these proteins are mostly reside in nucleus while gene drain in between nucleus and cell organelles were also found in some cases. The similarities and dissimilarities in between plants and other organisms' DRR pathways are discussed. The observed differences broaden our knowledge about DRR in the plants world, and raises the potential question of whether differentiated functions have evolved in some cases. These results, altogether, provide a useful framework for further experimental studies in these organisms.

  14. Effects of long-term radiation exposure on the higher aquatic plants in the Chernobyl exclusion zone

    Energy Technology Data Exchange (ETDEWEB)

    Shevtsova, N.; Gudkov, D. [Institute of Hydrobiology (Russian Federation)

    2014-07-01

    germinated seeds) and pinnacle deviations was registered in plants from the most radioactive contaminated water bodies. Also the decreasing of parasitic stability of one of aquatic plant communities' dominant species - the common reed is observed. The data of the mite Steneotarsonemus phragmitidis and the parasitic fungus Claviceps purpurea hitting of the common reed, correlated with radiation dose rate. It was determined the positive correlation between absorbed dose rate and chromosome aberration rate in roots of the twelve aquatic plants' species from sampling water bodies. The highest rate of chromosome aberrations (up to 17 %) were registered in plants with high level of morphological deviations in seeds germs, but not panicles. The data obtained from the complex analysis of natural aquatic plant communities from the radioactive contaminated water bodies testify about rather high level of genetic efficiency of low doses of long-term exposure. For higher aquatic plants from ChEZ there is observed a realization of radiobiological reactions on morphological and reproductive levels on the background of genetic instability induced by low doses. Document available in abstract form only. (authors)

  15. Interaction of higher plant ribosomal 5S RNAs with ''Xenopus laevis'' transcriptional factor IIIA

    International Nuclear Information System (INIS)

    Barciszewska, M.Z.

    1994-01-01

    In this paper transcriptional factor IIIA (TFIIIA) has been used as a probe for identity of three-dimensional-structure of eukaryotic 5S rRNAs. I was interested in finding a common motif in plant and ''Xenopus'' 5S rRNAs for TFIIIA recognition. I found that the two eukaryotic 5S rRNAs (from wheat germ and lupin seeds) are recognized by ''X. laevis'' TFIIIA and the data clearly suggest that these 5S rRNAs have very similar if not identical three-dimensional structures. Also effects of various conditions on stability of these complexes have been studied. (author). 30 refs, 6 figs, 1 tab

  16. Replacement power costs due to nuclear-plant outages: a higher standard of care

    International Nuclear Information System (INIS)

    Gransee, M.F.

    1982-01-01

    This article examines recent state public utility commission cases that deal with the high costs of replacement power that utilities must purchase after a nuclear power plant outage. Although most commissions have approved such expenses, it may be that there is a trend toward splitting the costs of such expenses between ratepayer and stockholder. Commissions are demanding a management prudence test to determine the cause of the outage and whether it meets the reasonable man standard before allowing these costs to be passed along to ratepayers. Unless the standard is applied with flexibility, however, utility companies could invoke the defenses covering traditional common law negligence

  17. A protochlorophyllide light-harvesting complex involved in de-etiolation of higher plants

    International Nuclear Information System (INIS)

    Reinbothe, C.; Lebedev, N.; Reinbothe, S.

    1999-01-01

    When etiolated angiosperm seedlings break through the soil after germination, they are immediately exposed to sunlight, but at this stage they are unable to perform photosynthesis1. In the absence of chlorophyll a and chlorophyll b, two other porphyrin species cooperate as the basic light-harvesting structure of etiolated plants. Protochlorophyllide a and protochlorophyllide b (ref. 2) form supramolecular complexes with NADPH and two closely related NADPH:protochlorophyllide oxidoreductase (POR) proteins—PORA and PORB (ref. 3)—in the prolamellar body of etioplasts. Here we report that these light-harvesting POR–protochlorophyllide complexes, named LHPP, are essential for the establishment of the photosynthetic apparatus and also confer photoprotection on the plant. They collect sunlight for rapid chlorophyll a biosynthesis and, simultaneously, dissipate excess light energy in the bulk of non-photoreducible protochlorophyllide b. Based on this dual function, it seems that LHPP provides the link between skotomorphogenesis and photosynthesis that is required for efficient de-etiolation

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

    Energy Technology Data Exchange (ETDEWEB)

    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).

  19. The role of silicon in higher plants under salinity and drought stress

    Directory of Open Access Journals (Sweden)

    Devrim Coskun

    2016-07-01

    Full Text Available 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.

  20. Achieving higher productivity of UO2 fuel at NUOFP through improved in-plant quality surveillance

    International Nuclear Information System (INIS)

    Meena, R.; Pramanik, D.; Sairam, S.; Rajkumar, J.V.; Rao, R.V.R.L.V.; Sinha, T.K.; Santra, N.; Rao, G.V.S.H.; Jayaraj, R.N.

    2009-01-01

    At Nuclear Fuel Complex (NFC), in the production of UO 2 fuel for PHWRs, a standard set of process parameters are monitored regularly for every lot of powder and pellet. Quality of intermediate products in the production process like UNP, ADU(dry), U 3 O 8 , UO 2+x , UO 2 granules, green pellets, sintered pellets are also regularly analysed/monitored apart from the final finished pellet and ensured to be within specified range. This range is decided by final product specifications and sometimes also based on the feed requirement in the next process in the downstream of the flow sheet. Vast experience gained over the years, behavior of various equipment under given set of conditions, feed back from the customer plants etc; have been primary criteria hither to, for defining the process conditions and chemical/physical properties of intermediate products

  1. Root uptake of uranium by a higher plant model (Phaseolus vulgaris) bioavailability from soil solution

    Energy Technology Data Exchange (ETDEWEB)

    Laroche, L.; Henner, P.; Camilleri, V.; Garnier-Laplace, J. [CEA Cadarache (DEI/SECRE/LRE), Laboratory of Radioecology and Ecotoxicology, Institute for Radioprotection and Nuclear Safety, 13 - Saint-Paul-lez-Durance (France)

    2004-07-01

    Uranium behaviour in soils is controlled by actions and interactions between physicochemical and biological processes that also determine its bioavailability. In soil solution, uranium(+VI) aqueous speciation undergoes tremendous changes mainly depending on pH, carbonates, phosphates and organic matter. In a first approach to identify bioavailable species of U to plants, cultures were performed using hydroponics, to allow an easy control of the composition of the exposure media. The latter, here an artificial soil solution, was designed to control the uranium species in solution. The geochemical speciation code JCHESS using a database compiled from the OECD/NEA thermochemical database project and verified was used to perform the solution speciation calculations. On this theoretical basis, three domains were defined for short-duration well-defined laboratory experiments in simplified conditions: pH 4.9, 5.8 and 7 where predicted dominant species are uranyl ions, hydroxyl complexes and carbonates respectively. For these domains, biokinetics and characterization of transmembrane transport according to a classical Michaelis Menten approach were investigated. The Free Ion Model (or its derived Biotic Ligand Model) was tested to determine if U uptake is governed by the free uranyl species or if other metal complexes can be assimilated. The effect of different variables on root assimilation efficiency and phyto-toxicity was explored: presence of ligands such as phosphates or carbonates and competitive ions such as Ca{sup 2+} at the 3 pH. According to previous experiments, uranium was principally located in roots whatever the pH and no difference in uranium uptake was evidenced between the main growth stages of the plant. Within the 3 studied chemical domains, results from short-term kinetics evidenced a linear correlation between total uranium concentration in bean roots and that in exposure media, suggesting that total uranium in soil solution could be a good predictor

  2. Root uptake of uranium by a higher plant model (Phaseolus vulgaris) bioavailability from soil solution

    International Nuclear Information System (INIS)

    Laroche, L.; Henner, P.; Camilleri, V.; Garnier-Laplace, J.

    2004-01-01

    Uranium behaviour in soils is controlled by actions and interactions between physicochemical and biological processes that also determine its bioavailability. In soil solution, uranium(+VI) aqueous speciation undergoes tremendous changes mainly depending on pH, carbonates, phosphates and organic matter. In a first approach to identify bioavailable species of U to plants, cultures were performed using hydroponics, to allow an easy control of the composition of the exposure media. The latter, here an artificial soil solution, was designed to control the uranium species in solution. The geochemical speciation code JCHESS using a database compiled from the OECD/NEA thermochemical database project and verified was used to perform the solution speciation calculations. On this theoretical basis, three domains were defined for short-duration well-defined laboratory experiments in simplified conditions: pH 4.9, 5.8 and 7 where predicted dominant species are uranyl ions, hydroxyl complexes and carbonates respectively. For these domains, biokinetics and characterization of transmembrane transport according to a classical Michaelis Menten approach were investigated. The Free Ion Model (or its derived Biotic Ligand Model) was tested to determine if U uptake is governed by the free uranyl species or if other metal complexes can be assimilated. The effect of different variables on root assimilation efficiency and phyto-toxicity was explored: presence of ligands such as phosphates or carbonates and competitive ions such as Ca 2+ at the 3 pH. According to previous experiments, uranium was principally located in roots whatever the pH and no difference in uranium uptake was evidenced between the main growth stages of the plant. Within the 3 studied chemical domains, results from short-term kinetics evidenced a linear correlation between total uranium concentration in bean roots and that in exposure media, suggesting that total uranium in soil solution could be a good predictor for

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

    Science.gov (United States)

    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.

  4. An iterative glycosyltransferase EntS catalyzes transfer and extension of O- and S-linked monosaccharide in enterocin 96.

    Science.gov (United States)

    Nagar, Rupa; Rao, Alka

    2017-05-12

    Glycosyltransferases are essential tools for in vitro-glycoengineering. Bacteria harbor an unexplored variety of protein glycosyltransferases. Here, we describe a peptide glycosyltransferase (EntS) encoded by ORF0417 of Enterococcus faecalis TX0104. EntS di-glycosylates linear peptide of enterocin 96- a known antibacterial, in vitro. It is capable of transferring as well as extending the glycan onto the peptide in an iterative sequential dissociative manner. It can catalyze multiple linkages: Glc/Gal(-O)Ser/Thr, Glc/Gal(-S)Cys and Glc/Gal(β)Glc/Gal(-O/S)Ser/Thr/Cys, in one pot. Using EntS generated glycovariants of enterocin 96 peptide, size and identity of the glycan are found to influence bioactivity of the peptide. The study identifies EntS as an enzyme worth pursuing, for in vitro peptide glycoengineering. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  5. UDP-Glycosyltransferases from the UGT73C Subfamily in Barbarea vulgaris Catalyze Sapogenin 3-O-Glucosylation in Saponin-Mediated Insect Resistance1[W][OA

    Science.gov (United States)

    Augustin, Jörg M.; Drok, Sylvia; Shinoda, Tetsuro; Sanmiya, Kazutsuka; Nielsen, Jens Kvist; Khakimov, Bekzod; Olsen, Carl Erik; Hansen, Esben Halkjær; Kuzina, Vera; Ekstrøm, Claus Thorn; Hauser, Thure; Bak, Søren

    2012-01-01

    Triterpenoid saponins are bioactive metabolites that have evolved recurrently in plants, presumably for defense. Their biosynthesis is poorly understood, as is the relationship between bioactivity and structure. Barbarea vulgaris is the only crucifer known to produce saponins. Hederagenin and oleanolic acid cellobioside make some B. vulgaris plants resistant to important insect pests, while other, susceptible plants produce different saponins. Resistance could be caused by glucosylation of the sapogenins. We identified four family 1 glycosyltransferases (UGTs) that catalyze 3-O-glucosylation of the sapogenins oleanolic acid and hederagenin. Among these, UGT73C10 and UGT73C11 show highest activity, substrate specificity and regiospecificity, and are under positive selection, while UGT73C12 and UGT73C13 show lower substrate specificity and regiospecificity and are under purifying selection. The expression of UGT73C10 and UGT73C11 in different B. vulgaris organs correlates with saponin abundance. Monoglucosylated hederagenin and oleanolic acid were produced in vitro and tested for effects on P. nemorum. 3-O-β-d-Glc hederagenin strongly deterred feeding, while 3-O-β-d-Glc oleanolic acid only had a minor effect, showing that hydroxylation of C23 is important for resistance to this herbivore. The closest homolog in Arabidopsis thaliana, UGT73C5, only showed weak activity toward sapogenins. This indicates that UGT73C10 and UGT73C11 have neofunctionalized to specifically glucosylate sapogenins at the C3 position and demonstrates that C3 monoglucosylation activates resistance. As the UGTs from both the resistant and susceptible types of B. vulgaris glucosylate sapogenins and are not located in the known quantitative trait loci for resistance, the difference between the susceptible and resistant plant types is determined at an earlier stage in saponin biosynthesis. PMID:23027665

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

    Science.gov (United States)

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

    2016-04-28

    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.

  7. Red mud a byproduct of aluminum production contains soluble vanadium that causes genotoxic and cytotoxic effects in higher plants

    Energy Technology Data Exchange (ETDEWEB)

    Mišík, Miroslav [Institute of Cancer Research, Department of Medicine I, Comprehensive Cancer Center, Medical University of Vienna, Vienna (Austria); Burke, Ian T. [Earth Surface Science Institute, School of Earth and Environment, University of Leeds, Leeds LS2 9JT (United Kingdom); Reismüller, Matthias; Pichler, Clemens; Rainer, Bernhard [Institute of Cancer Research, Department of Medicine I, Comprehensive Cancer Center, Medical University of Vienna, Vienna (Austria); Mišíková, Katarina [Department of Botany, Faculty of Natural Sciences, Comenius University, Bratislava (Slovakia); Mayes, William M. [Centre for Environmental and Marine Sciences, University of Hull, Scarborough YO11 3AZ (United Kingdom); Knasmueller, Siegfried, E-mail: siegfried.knasmueller@meduniwien.ac.at [Institute of Cancer Research, Department of Medicine I, Comprehensive Cancer Center, Medical University of Vienna, Vienna (Austria)

    2014-09-15

    Red mud (RM) is a byproduct of aluminum production; worldwide between 70 and 120 million tons is produced annually. We analyzed RM which was released in the course of the Kolontar disaster in Hungary into the environment in acute and genotoxicity experiments with plants which are widely used for environmental monitoring. We detected induction of micronuclei which reflect chromosomal damage in tetrads of Tradescantia and in root cells of Allium as well as retardation of root growth with contaminated soils and leachates. Chemical analyses showed that RM contains metals, in particular high concentrations of vanadium. Follow-up experiments indicated that vanadate causes the effects in the plants. This compound causes also in humans DNA damage and positive results were obtained in carcinogenicity studies. Since it was found also in RM from other production sites our findings indicate that its release in the environment is a global problem which should be studied in more detail. Capsule abstract: Our findings indicate that the red mud causes genotoxic effect in plants probably due to the presence of vanadate which is contained at high concentrations in the residue. - Highlights: • Red mud, a by-product of aluminum production, causes DNA-damage in higher plants. • We showed that this effect is caused by vanadate a known carcinogenic genotoxin. • Vanadate is contained in high concentrations in the residue. • Release of red mud may cause adverse effects in ecosystems and affect human health.

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

    Science.gov (United States)

    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.

  9. A novel aromatic alcohol dehydrogenase in higher plants: molecular cloning and expression.

    Science.gov (United States)

    Goffner, D; Van Doorsselaere, J; Yahiaoui, N; Samaj, J; Grima-Pettenati, J; Boudet, A M

    1998-03-01

    Cinnamyl alcohol dehydrogenase (CAD; EC 1.1.195) catalyses the conversion of p-hydroxy-cinnamaldehydes to the corresponding alcohols and is considered a key enzyme in lignin biosynthesis. In a previous study, an atypical form of CAD (CAD 1) was identified in Eucalyptus gunnii [12]. We report here the molecular cloning and characterization of the corresponding cDNA, CAD 1-5, which encodes this novel aromatic alcohol dehydrogenase. The identity of CAD 1-5 was unambiguously confirmed by sequence comparison of the cDNA with peptide sequences derived from purified CAD 1 protein and by functional expression of CAD 1 recombinant protein in Escherichia coli. Both native and recombinant CAD 1 exhibit high affinity towards lignin precursors including 4-coumaraldehyde and coniferaldehyde, but they do not accept sinapaldehyde. Moreover, recombinant CAD 1 can also utilize a wide range of aromatic substrates including unsubstituted and substituted benzaldehydes. The open reading frame of CAD 1-5 encodes a protein with a calculated molecular mass of 35,790 Da and an isoelectric point of 8.1. Although sequence comparisons with proteins in databases revealed significant similarities with dihydroflavonol-4-reductases (DFR; EC 1.1.1.219) from a wide range of plant species, the most striking similarity was found with cinnamoyl-CoA reductase (CCR; EC 1.2.1.44), the enzyme which directly precedes CAD in the lignin biosynthetic pathway. RNA blot analysis and immunolocalization experiments indicated that CAD 1 is expressed in both lignified and unlignified tissues/cells. Based on the catalytic activity of CAD 1 in vitro and its localization in planta, CAD 1 may function as an 'alternative' enzyme in the lignin biosynthetic pathway. However, additional roles in phenolic metabolism are not excluded.

  10. Probing the Catalytic Promiscuity of a Regio- and Stereospecific C-Glycosyltransferase from Mangifera indica.

    Science.gov (United States)

    Chen, Dawei; Chen, Ridao; Wang, Ruishan; Li, Jianhua; Xie, Kebo; Bian, Chuancai; Sun, Lili; Zhang, Xiaolin; Liu, Jimei; Yang, Lin; Ye, Fei; Yu, Xiaoming; Dai, Jungui

    2015-10-19

    The catalytic promiscuity of the novel benzophenone C-glycosyltransferase, MiCGT, which is involved in the biosynthesis of mangiferin from Mangifera indica, was explored. MiCGT exhibited a robust capability to regio- and stereospecific C-glycosylation of 35 structurally diverse druglike scaffolds and simple phenolics with UDP-glucose, and also formed O- and N-glycosides. Moreover, MiCGT was able to generate C-xylosides with UDP-xylose. The OGT-reversibility of MiCGT was also exploited to generate C-glucosides with simple sugar donor. Three aryl-C-glycosides exhibited potent SGLT2 inhibitory activities with IC50  values of 2.6×, 7.6×, and 7.6×10(-7)  M, respectively. These findings demonstrate for the first time the significant potential of an enzymatic approach to diversification through C-glycosidation of bioactive natural and unnatural products in drug discovery. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Crystal Structure of a UDP-glucose-specific Glycosyltransferase from a Mycobacterium Species

    Energy Technology Data Exchange (ETDEWEB)

    Fulton, Zara; McAlister, Adrian; Wilce, Matthew C.J.; Brammananth, Rajini; Zaker-Tabrizi, Leyla; Perugini, Matthew A.; Bottomley, Stephen P.; Coppel, Ross L.; Crellin, Paul K.; Rossjohn, Jamie; Beddoe, Travis (Monash); (Melbourne)

    2008-10-24

    Glycosyltransferases (GTs) are a large and ubiquitous family of enzymes that specifically transfer sugar moieties to a range of substrates. Mycobacterium tuberculosis contains a large number of GTs, many of which are implicated in cell wall synthesis, yet the majority of these GTs remain poorly characterized. Here, we report the high resolution crystal structures of an essential GT (MAP2569c) from Mycobacterium avium subsp. paratuberculosis (a close homologue of Rv1208 from M. tuberculosis) in its apo- and ligand-bound forms. The structure adopted the GT-A fold and possessed the characteristic DXD motif that coordinated an Mn{sup 2+} ion. Atypical of most GTs characterized to date, MAP2569c exhibited specificity toward the donor substrate, UDP-glucose. The structure of this ligated complex revealed an induced fit binding mechanism and provided a basis for this unique specificity. Collectively, the structural features suggested that MAP2569c may adopt a 'retaining' enzymatic mechanism, which has implications for the classification of other GTs in this large superfamily.

  12. Peptidoglycan glycosyltransferase substrate mimics as templates for the design of new antibacterial drugs

    Directory of Open Access Journals (Sweden)

    Adeline eDerouaux

    2013-03-01

    Full Text Available Peptidoglycan (PG is an essential net-like macromolecule that surrounds bacteria, gives them their shape, and protects them against their own high osmotic pressure. PG synthesis inhibition leads to bacterial cell lysis, making it an important target for many antibiotics. The final two reactions in PG synthesis are performed by penicillin-binding proteins (PBPs. Their glycosyltransferase (GT activity uses the lipid II precursor to synthesize glycan chains and their transpeptidase (TP activity catalyzes the cross-linking of two glycan chains via the peptide side chains. Inhibition of either of these two reactions leads to bacterial cell death. β-Lactam antibiotics target the transpeptidation reaction while antibiotic therapy based on inhibition of the GTs remains to be developed. Ongoing research is trying to fill this gap by studying the interactions of GTs with inhibitors and substrate mimics and utilizing the latter as templates for the design of new antibiotics. In this mini review we present an updated overview on the GTs and describe the structure-activity relationship of recently developed synthetic ligands.

  13. The Glycosyltransferases of LPS Core: A Review of Four Heptosyltransferase Enzymes in Context

    Directory of Open Access Journals (Sweden)

    Joy M. Cote

    2017-10-01

    Full Text Available Bacterial antibiotic resistance is a rapidly expanding problem in the world today. Functionalization of the outer membrane of Gram-negative bacteria provides protection from extracellular antimicrobials, and serves as an innate resistance mechanism. Lipopolysaccharides (LPS are a major cell-surface component of Gram-negative bacteria that contribute to protecting the bacterium from extracellular threats. LPS is biosynthesized by the sequential addition of sugar moieties by a number of glycosyltransferases (GTs. Heptosyltransferases catalyze the addition of multiple heptose sugars to form the core region of LPS; there are at most four heptosyltransferases found in all Gram-negative bacteria. The most studied of the four is HepI. Cells deficient in HepI display a truncated LPS on their cell surface, causing them to be more susceptible to hydrophobic antibiotics. HepI–IV are all structurally similar members of the GT-B structural family, a class of enzymes that have been found to be highly dynamic. Understanding conformational changes of heptosyltransferases are important to efficiently inhibiting them, but also contributing to the understanding of all GT-B enzymes. Finding new and smarter methods to inhibit bacterial growth is crucial, and the Heptosyltransferases may provide an important model for how to inhibit many GT-B enzymes.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  15. A database of PCR primers for the chloroplast genomes of higher plants

    Science.gov (United States)

    Heinze, Berthold

    2007-01-01

    Background Chloroplast genomes evolve slowly and many primers for PCR amplification and analysis of chloroplast sequences can be used across a wide array of genera. In some cases 'universal' primers have been designed for the purpose of working across species boundaries. However, the essential information on these primer sequences is scattered throughout the literature. Results A database is presented here which assembles published primer information for chloroplast DNA. Additional primers were designed to fill gaps where little or no primer information could be found. Amplicons are either the genes themselves (typically useful in studies of sequence variation in higher-order phylogeny) or they are spacers, introns, and intergenic regions (for studies of phylogeographic patterns within and among species). The current list of 'generic' primers consists of more than 700 sequences. Wherever possible, we give the locations of the primers in the thirteen fully sequenced chloroplast genomes (Nicotiana tabacum, Atropa belladonna, Spinacia oleracea, Arabidopsis thaliana, Populus trichocarpa, Oryza sativa, Pinus thunbergii, Marchantia polymorpha, Zea mays, Oenothera elata, Acorus calamus, Eucalyptus globulus, Medicago trunculata). Conclusion The database described here is designed to serve as a resource for researchers who are venturing into the study of poorly described chloroplast genomes, whether for large- or small-scale DNA sequencing projects, to study molecular variation or to investigate chloroplast evolution. PMID:17326828

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  17. A database of PCR primers for the chloroplast genomes of higher plants

    Directory of Open Access Journals (Sweden)

    Heinze Berthold

    2007-02-01

    Full Text Available Abstract Background Chloroplast genomes evolve slowly and many primers for PCR amplification and analysis of chloroplast sequences can be used across a wide array of genera. In some cases 'universal' primers have been designed for the purpose of working across species boundaries. However, the essential information on these primer sequences is scattered throughout the literature. Results A database is presented here which assembles published primer information for chloroplast DNA. Additional primers were designed to fill gaps where little or no primer information could be found. Amplicons are either the genes themselves (typically useful in studies of sequence variation in higher-order phylogeny or they are spacers, introns, and intergenic regions (for studies of phylogeographic patterns within and among species. The current list of 'generic' primers consists of more than 700 sequences. Wherever possible, we give the locations of the primers in the thirteen fully sequenced chloroplast genomes (Nicotiana tabacum, Atropa belladonna, Spinacia oleracea, Arabidopsis thaliana, Populus trichocarpa, Oryza sativa, Pinus thunbergii, Marchantia polymorpha, Zea mays, Oenothera elata, Acorus calamus, Eucalyptus globulus, Medicago trunculata. Conclusion The database described here is designed to serve as a resource for researchers who are venturing into the study of poorly described chloroplast genomes, whether for large- or small-scale DNA sequencing projects, to study molecular variation or to investigate chloroplast evolution.

  18. Conservation between higher plants and the moss Physcomitrella patens in response to the phytohormone abscisic acid: a proteomics analysis

    Directory of Open Access Journals (Sweden)

    Wang Xiaoqin

    2010-08-01

    accumulation levels as a result of treatment with ABA. Detailed analysis these protein functions showed that physiological and molecular responses to the plant hormone ABA appear to be conserved among higher plant species and bryophytes.

  19. Identification and characterization of glycosyltransferases involved in the synthesis of the side chains of the cell wall pectic polysaccharide rhamnogalacturonan II

    Energy Technology Data Exchange (ETDEWEB)

    O' Neill, Malcolm [Univ. of Georgia, Athens, GA (United States)

    2015-08-31

    Our goal was to gain insight into the genes and proteins involved in the biosynthesis of rhamnogalacturonan II (RG-II), a borate cross-linked and structurally conserved pectic polysaccharide present in the primary cell walls of all vascular plants. The research conducted during the funding period established that (i) Avascular plants have the ability to synthesize UDP-apiose but lack the glycosyltransferase machinery required to synthesize RG-II or other apiose-containing cell wall glycans. (ii) RG-II structure is highly conserved in the Lemnaceae (duckweeds and relatives). However, the structures of other wall pectins and hemicellulose have changed substantial during the diversification of the Lemnaceae. This supports the notion that a precise structure of RG-II must be maintained to allow borate cross-linking to occur in a controlled manner. (iii) Enzymes involved in the conversion of UDP-GlcA to UDP-Api, UDP-Xyl, and UDP-Ara may have an important role in controlling the composition of duckweed cell walls. (iv) RG-II exists as the borate ester cross-linked dimer in the cell walls of soybean root hairs and roots. Thus, RG-II is present in the walls of plants cells that grow by tip or by expansive growth. (v) A reduction in RG-II cross-linking in the maize tls1 mutant, which lacks a borate channel protein, suggests that the growth defects observed in the mutant are, at least in part, due to defects in the cell wall.

  20. Structure of the higher plant light harvesting complex I: in vivo characterization and structural interdependence of the Lhca proteins.

    Science.gov (United States)

    Klimmek, Frank; Ganeteg, Ulrika; Ihalainen, Janne A; van Roon, Henny; Jensen, Poul E; Scheller, Henrik V; Dekker, Jan P; Jansson, Stefan

    2005-03-01

    We have investigated the structure of the higher plant light harvesting complex of photosystem I (LHCI) by analyzing PSI-LHCI particles isolated from a set of Arabidopsis plant lines, each lacking a specific Lhca (Lhca1-4) polypeptide. Functional antenna size measurements support the recent finding that there are four Lhca proteins per PSI in the crystal structure [Ben-Shem, A., Frolow, F., and Nelson, N. (2003) Nature 426, 630-635]. According to HPLC analyses the number of pigment molecules bound within the LHCI is higher than expected from reconstitution studies or analyses of isolated native LHCI. Comparison of the spectra of the particles from the different lines reveals chlorophyll absorption bands peaking at 696, 688, 665, and 655 nm that are not present in isolated PSI or LHCI. These bands presumably originate from "gap" or "linker" pigments that are cooperatively coordinated by the Lhca and/or PSI proteins, which we have tentatively localized in the PSI-LHCI complex.

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

    Directory of Open Access Journals (Sweden)

    Abir U Igamberdiev

    2016-07-01

    Full Text Available 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.

  2. Plant glyco-biotechnology on the way to synthetic biology

    Directory of Open Access Journals (Sweden)

    Andreas eLoos

    2014-10-01

    Full Text Available Plants are increasingly being used for the production of recombinant proteins. One reason is that plants are highly amenable for glycan engineering processes and allow the production of therapeutic proteins with increased efficacies due to optimized glycosylation profiles. Removal and insertion of glycosylation reactions by knock-out/knock-down approaches and introduction of glycosylation enzymes have paved the way for the humanization of the plant glycosylation pathway. The insertion of heterologous enzymes at exactly the right stage of the existing glycosylation pathway has turned out to be of utmost importance for optimal results. To enable such precise targeting chimeric enzymes have been constructed. In this short review we will exemplify the importance of correct targeting of glycosyltransferases, we will give an overview of the targeting mechanism of glycosyltransferases, describe chimeric enzymes used in plant N-glycosylation engineering and illustrate how plant glycoengineering builds on the tools offered by synthetic biology to construct such chimeric enzymes.

  3. Higher photosynthesis, nutrient- and energy-use efficiencies contribute to invasiveness of exotic plants in a nutrient poor habitat in northeast China.

    Science.gov (United States)

    Liu, Ming-Chao; Kong, De-Liang; Lu, Xiu-Rong; Huang, Kai; Wang, Shuo; Wang, Wei-Bin; Qu, Bo; Feng, Yu-Long

    2017-08-01

    The roles of photosynthesis-related traits in invasiveness of introduced plant species are still not well elucidated, especially in nutrient-poor habitats. In addition, little effort has been made to determine the physiological causes and consequences of the difference in these traits between invasive and native plants. To address these problems, we compared the differences in 16 leaf functional traits related to light-saturated photosynthetic rate (P max ) between 22 invasive and native plants in a nutrient-poor habitat in northeast China. The invasive plants had significantly higher P max , photosynthetic nitrogen- (PNUE), phosphorus- (PPUE), potassium- (PKUE) and energy-use efficiencies (PEUE) than the co-occurring natives, while leaf nutrient concentrations, construction cost (CC) and specific leaf area were not significantly different between the invasive and native plants. The higher PNUE contributed to higher P max for the invasive plants, which in turn contributed to higher PPUE, PKUE and PEUE. CC changed independently with other traits such as P max , PNUE, PPUE, PKUE and PEUE, showing two trait dimensions, which may facilitate acclimation to multifarious niche dimensions. Our results indicate that the invasive plants have a superior resource-use strategy, i.e. higher photosynthesis under similar resource investments, contributing to invasion success in the barren habitat. © 2017 Scandinavian Plant Physiology Society.

  4. UGT74AN1, a Permissive Glycosyltransferase from Asclepias curassavica for the Regiospecific Steroid 3-O-Glycosylation.

    Science.gov (United States)

    Wen, Chao; Huang, Wei; Zhu, Xue-Lin; Li, Xiao-San; Zhang, Fan; Jiang, Ren-Wang

    2018-02-02

    A permissive steroid glycosyltransferase (UGT74AN1) from Asclepias curassavica exhibited robust capabilities for the regiospecific C3 glycosylation of cardiotonic steroids and C 21 steroid precursors, and unprecedented promiscuity toward 53 structurally diverse natural and unnatural compounds to form O-, N-, and S-glycosides, along with the catalytic reversibility for a one-pot transglycosylation reaction. These findings highlight UGT74AN1 as the first regiospecific catalyst for cardiotonic steroid C3 glycosylation and exhibit significant potential for glycosylation of diverse bioactive molecules in drug discovery.

  5. Structural characterization of O- and C-glycosylating variants of the landomycin glycosyltransferase LanGT2.

    Science.gov (United States)

    Tam, Heng Keat; Härle, Johannes; Gerhardt, Stefan; Rohr, Jürgen; Wang, Guojun; Thorson, Jon S; Bigot, Aurélien; Lutterbeck, Monika; Seiche, Wolfgang; Breit, Bernhard; Bechthold, Andreas; Einsle, Oliver

    2015-02-23

    The structures of the O-glycosyltransferase LanGT2 and the engineered, C-C bond-forming variant LanGT2S8Ac show how the replacement of a single loop can change the functionality of the enzyme. Crystal structures of the enzymes in complex with a nonhydrolyzable nucleotide-sugar analogue revealed that there is a conformational transition to create the binding sites for the aglycon substrate. This induced-fit transition was explored by molecular docking experiments with various aglycon substrates. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Extraction of Crude Chitinase from Higher Plants and their Chitin-Hydrolysis Activities; Kotosyokubutu yurai kichinaze no chusyutu to kichin bunkai kassei

    Energy Technology Data Exchange (ETDEWEB)

    Kondo, K.; Harada, K.; Shibata, M.; Maeda, R. [Doshisha Univ., Kyoto (Japan). Faculty of Engineering

    1997-07-10

    To prepare a purified chitinase from higher plants, firstly, crude enzymes were extracted from six higher plants, namely, radish seeds, sunflower seeds, watermelon seeds, bamboo leaves, orange skin, and persimmon skin. Using these crude enzymes, pH dependencies of hydrolysis reaction of colloidal chitin are investigated. For radish seeds and bamboo leaves, which have relatively high activities, the kinetics of enzymatic reaction are studies. It is clear that these reactions obey Michaelis-Menten kinetics. 7 refs., 3 figs., 2 tabs.

  7. Cyclodextrin glycosyltransferase from Bacillus licheniformis: optimization of production and its properties Cyclodextrina glycosyltransferase de Bacillus licheniformis: otimização da produção e suas propriedades

    Directory of Open Access Journals (Sweden)

    Paulo Roberto Martins Bonilha

    2006-09-01

    Full Text Available Cyclodextrin glycosyltransferase (EC 2.4.1.19 is an enzyme that produces cyclodextrins from starch via an intramolecular transglycosylation reaction. An alkalophilic Bacillus strain, isolated from cassava peels, was identified as Bacillus licheniformis. CGTase production by this strain was better when potato starch was used as carbon source, followed by cassava starch and amylopectin. Glucose and amylose, on the other hand, acted as synthesis repressors. When the cultivation was supplemented with sodium ions and had the pH adjusted between 6.0 and 9.0, the microorganism maintained the growth and enzyme production capacity. This data is interesting because it contradicts the concept that alkalophilic microorganisms do not grow in this pH range. After ultrafiltration-centrifugation, one protein of 85.2 kDa with CGTase activity was isolated. This protein was identified in plates with starch and phenolphthalein. Determination of the optimum temperature showed higher activities at 25ºC and 55ºC, indicating the possible presence of more than one CGTase in the culture filtrate. Km and Vmax values were 1.77 mg/mL and 0.0263 U/mg protein, respectively, using potato starch as substrate.Ciclodextrina glicosiltransferase (EC 2.4.1.19 é uma enzima que produz ciclodextrinas a partir de amido via transglicosilação intramolecular. Uma cepa de Bacillus alcalofílico, isolada de cascas de mandioca, foi identificada como Bacillus licheniformis. A produção de CGTase por esta cepa foi melhor quando amido de batata foi utilizado como fonte de carbono, seguido por amido de mandioca e amilopectina. Glicose e amilose, por outro lado, atuaram como repressor de síntese desta enzima. Quando o cultivo foi suplementado com íons sódio e teve o pH ajustado entre 6,0 e 9,0, o microrganismo manteve a capacidade de crescimento e de produção da enzima. Este dado é interessante pois contraria o conceito de que microrganismos alcalofílicos não apresentam crescimento

  8. Effects of genetic modifications to flax (Linum usitatissimum) on arbuscular mycorrhiza and plant performance.

    Science.gov (United States)

    Wróbel-Kwiatkowska, Magdalena; Turnau, Katarzyna; Góralska, Katarzyna; Anielska, Teresa; Szopa, Jan

    2012-10-01

    Although arbuscular mycorrhizal fungi (AMF) are known for their positive effect on flax growth, the impact of genetic manipulation in this crop on arbuscular mycorrhiza and plant performance was assessed for the first time. Five types of transgenic flax that were generated to improve fiber quality and resistance to pathogens, through increased levels of either phenylpropanoids (W92.40), glycosyltransferase (GT4, GT5), or PR2 beta-1,3-glucanase (B14) or produce polyhydroxybutyrate (M50), were used. Introduced genetic modifications did not change the degree of mycorrhizal colonization as compared to parent cultivars Linola and Nike. Arbuscules were well developed in each tested transgenic type (except M50). In two lines (W92.40 and B14), a higher abundance of arbuscules was observed when compared to control, untransformed flax plants. However, in some cases (W92.40, GT4, GT5, and B14 Md), the mycorrhizal dependency for biomass production of transgenic plants was slightly lower when compared to the original cultivars. No significant influence of mycorrhiza on the photosynthetic activity of transformed lines was found, but in most cases P concentration in mycorrhizal plants remained higher than in nonmycorrhizal ones. The transformed flax lines meet the demands for better quality of fiber and higher resistance to pathogens, without significantly influencing the interaction with AMF.

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

    Science.gov (United States)

    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.

  10. Higher plant availability and reduced reactor scram frequency in PWRs by appropriate system and I and C design

    International Nuclear Information System (INIS)

    Frei, G.; Weber, J.

    1987-01-01

    High plant availability and reliability are guaranteed by appropriate design of reactor and BOP systems, this including the plant I and C systems. It is of advantage to have design, construction and commissioning of the plant concentrated in the hands of a single company to avoid interface problems between the different areas of the plant. The integrated overall control concept developed by KWU with control, limitation and protection systems as well as optimized operational and monitoring systems assisted by instrumentation channel redundance and logic for selection of the second highest (or second lowest) signal value as appropriate for comparison with limitation setpoints, minimize the severity of transients. This results in a reduction in the frequency of reactor scrams and of unnecessary actuation of safety systems. Dynamic plant behavior is described for a number of examples where the improved plant behavior resulting from the above design features enhances plant availability

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

    International Nuclear Information System (INIS)

    Huang, X.D.; Dixon, D.G.; Greenberg, B.M.

    1993-01-01

    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 π-orbital systems of PAHs, can be a major factor in PAH toxicity. Light activation of PAHs is known to occur via photosensitization reactions (generation of singlet oxygen and superoxide) and potentially by photomodification of the chemicals (photooxidation and/or photolysis) to more toxic species. To examine the modes of PAH action in the light and determine if the photomodified compounds are hazardous, we 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 activate 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 (half-lives in hours), 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Zeevaart, J.A.D.; Heath, T.G.; Gage, D.A. (Michigan State University, East Lansing (USA))

    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.

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

    International Nuclear Information System (INIS)

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

    1989-01-01

    Previous labeling studies of abscisic acid (ABA) with 18 O 2 have been mainly conducted with water-stressed leaves. In this study, 18 O incorporation into ABA of stressed leaves of various species was compared with 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), 18 O was most abundant in the carboxyl group, whereas incorporation of a second and third 18 O in the oxygen atoms on the ring of ABA was much less prominent after 24 h in 18 O 2 . ABA from turgid bean leaves showed significant 18 O incorporation, again with highest 18 O enrichment in the carboxyl group. On the basis of 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

  14. Effective integration between heavy water plant and fertilizer plant for higher production of heavy water (D2O) (Preprint No. PD-10)

    International Nuclear Information System (INIS)

    Periakaruppan, M.; Gupta, S.K.; Bhowmick, S.C.

    1989-04-01

    For smooth and efficient running of heavy water plants linked with fertilize r plants, it is necessary that certain factors must be taken into consideration right from the design stage of a fertilizer plant. These factors are: (1)preventing loss in D 2 concentration in syn gas, (2)keeping the level of CO 2 and CO in syn gas below 1 ppm, (3)operating the ammonia plant at highest pressure and (4)keeping the feed gas ammonia supply available without any interruption. Incorporation of these factors in the design is discussed. (M.G.B. )

  15. A Studi on High Plant Systems Course with Active Learning in Higher Education Through Outdoor Learning to Increase Student Learning Activities

    OpenAIRE

    Nur Rokhimah Hanik, Anwari Adi Nugroho

    2015-01-01

    Biology learning especially high plant system courses needs to be applied to active learning centered on the student (Active Learning In Higher Education) to enhance the students' learning activities so that the quality of learning for the better. Outdoor Learning is one of the active learning invites students to learn outside of the classroom by exploring the surrounding environment. This research aims to improve the students' learning activities in the course of high plant systems through t...

  16. Transport and compartmentation of phosphite in higher plant cells - kinetic and 31P nuclear magnetic resonance studies

    NARCIS (Netherlands)

    Danova-Alt, R.; Dijkema, C.; Waard, de P.; Köck, M.

    2008-01-01

    Phosphite (Phi, H(2)PO(3)(-)), being the active part of several fungicides, has been shown to influence not only the fungal metabolism but also the development of phosphate-deficient plants. However, the mechanism of phosphite effects on plants is still widely unknown. In this paper we analysed

  17. Crystal Structures of Glycosyltransferase UGT78G1 Reveal the Molecular Basis for Glycosylation and Deglycosylation of (Iso)flavonoids

    Energy Technology Data Exchange (ETDEWEB)

    Modolo, Luzia V.; Li, Lenong; Pan, Haiyun; Blount, Jack W.; Dixon, Richard A.; Wang, Xiaoqiang; (SRNF)

    2010-09-21

    The glycosyltransferase UGT78G1 from Medicago truncatula catalyzes the glycosylation of various (iso)flavonoids such as the flavonols kaempferol and myricetin, the isoflavone formononetin, and the anthocyanidins pelargonidin and cyanidin. It also catalyzes a reverse reaction to remove the sugar moiety from glycosides. The structures of UGT78G1 bound with uridine diphosphate or with both uridine diphosphate and myricetin were determined at 2.1 {angstrom} resolution, revealing detailed interactions between the enzyme and substrates/products and suggesting a distinct binding mode for the acceptor/product. Comparative structural analysis and mutagenesis identify glutamate 192 as a key amino acid for the reverse reaction. This information provides a basis for enzyme engineering to manipulate substrate specificity and to design effective biocatalysts with glycosylation and/or deglycosylation activity.

  18. Overexpression of Brucella putative glycosyltransferase WbkA in B. abortus RB51 leads to production of exopolysaccharide

    Directory of Open Access Journals (Sweden)

    Neha eDabral

    2015-06-01

    Full Text Available Brucella spp. are Gram-negative, facultative intracellular bacteria that cause brucellosis in mammals. Brucella strains containing the O-polysaccharide in their cell wall structure exhibit a smooth phenotype whereas the strains devoid of the polysaccharide show rough phenotype. B. abortus strain RB51 is a stable rough attenuated mutant which is used as a licensed live vaccine for bovine brucellosis. Previous studies have shown that the wboA gene, which encodes a glycosyltransferase required for the synthesis of O-polysaccharide, is disrupted in B. abortus RB51 by an IS711 element. Although complementation of strain RB51 with a functional wboA gene results in O-polysaccharide synthesis in the cytoplasm, it does not result in smooth phenotype. The aim of this study was to determine if overexpression of Brucella WbkA or WbkE, two additional putative glycosyltransferases essential for O-polysaccharide synthesis, in strain RB51 would result in the O-polysaccharide synthesis and smooth phenotype. Our results demonstrate that overexpression of wbkA or wbkE gene in RB51 does not result in O-polysaccharide expression as shown by Western blotting with specific antibodies. However, wbkA, but not wbkE, overexpression leads to the development of a clumping phenotype and the production of exopolysaccharide(s containing mannose, galactose, N-acetylglucosamine and N-acetylgalactosamine. Moreover, we found that the clumping recombinant strain displays increased adhesion to polystyrene plates. The recombinant strain was similar to strain RB51 in its attenuation characteristic and in its ability to induce protective immunity against virulent B. abortus challenge in mice.

  19. Overexpression of Brucella putative glycosyltransferase WbkA in B. abortus RB51 leads to production of exopolysaccharide.

    Science.gov (United States)

    Dabral, Neha; Jain-Gupta, Neeta; Seleem, Mohamed N; Sriranganathan, Nammalwar; Vemulapalli, Ramesh

    2015-01-01

    Brucella spp. are Gram-negative, facultative intracellular bacteria that cause brucellosis in mammals. Brucella strains containing the O-polysaccharide in their cell wall structure exhibit a smooth phenotype whereas the strains devoid of the polysaccharide show rough phenotype. B. abortus strain RB51 is a stable rough attenuated mutant which is used as a licensed live vaccine for bovine brucellosis. Previous studies have shown that the wboA gene, which encodes a glycosyltransferase required for the synthesis of O-polysaccharide, is disrupted in B. abortus RB51 by an IS711 element. Although complementation of strain RB51 with a functional wboA gene results in O-polysaccharide synthesis in the cytoplasm, it does not result in smooth phenotype. The aim of this study was to determine if overexpression of Brucella WbkA or WbkE, two additional putative glycosyltransferases essential for O-polysaccharide synthesis, in strain RB51 would result in the O-polysaccharide synthesis and smooth phenotype. Our results demonstrate that overexpression of wbkA or wbkE gene in RB51 does not result in O-polysaccharide expression as shown by Western blotting with specific antibodies. However, wbkA, but not wbkE, overexpression leads to the development of a clumping phenotype and the production of exopolysaccharide(s) containing mannose, galactose, N-acetylglucosamine, and N-acetylgalactosamine. Moreover, we found that the clumping recombinant strain displays increased adhesion to polystyrene plates. The recombinant strain was similar to strain RB51 in its attenuation characteristic and in its ability to induce protective immunity against virulent B. abortus challenge in mice.

  20. Snf2 family gene distribution in higher plant genomes reveals DRD1 expansion and diversification in the tomato genome.

    Science.gov (United States)

    Bargsten, Joachim W; Folta, Adam; Mlynárová, Ludmila; Nap, Jan-Peter

    2013-01-01

    As part of large protein complexes, Snf2 family ATPases are responsible for energy supply during chromatin remodeling, but the precise mechanism of action of many of these proteins is largely unknown. They influence many processes in plants, such as the response to environmental stress. This analysis is the first comprehensive study of Snf2 family ATPases in plants. We here present a comparative analysis of 1159 candidate plant Snf2 genes in 33 complete and annotated plant genomes, including two green algae. The number of Snf2 ATPases shows considerable variation across plant genomes (17-63 genes). The DRD1, Rad5/16 and Snf2 subfamily members occur most often. Detailed analysis of the plant-specific DRD1 subfamily in related plant genomes shows the occurrence of a complex series of evolutionary events. Notably tomato carries unexpected gene expansions of DRD1 gene members. Most of these genes are expressed in tomato, although at low levels and with distinct tissue or organ specificity. In contrast, the Snf2 subfamily genes tend to be expressed constitutively in tomato. The results underpin and extend the Snf2 subfamily classification, which could help to determine the various functional roles of Snf2 ATPases and to target environmental stress tolerance and yield in future breeding.

  1. Snf2 family gene distribution in higher plant genomes reveals DRD1 expansion and diversification in the tomato genome.

    Directory of Open Access Journals (Sweden)

    Joachim W Bargsten

    Full Text Available As part of large protein complexes, Snf2 family ATPases are responsible for energy supply during chromatin remodeling, but the precise mechanism of action of many of these proteins is largely unknown. They influence many processes in plants, such as the response to environmental stress. This analysis is the first comprehensive study of Snf2 family ATPases in plants. We here present a comparative analysis of 1159 candidate plant Snf2 genes in 33 complete and annotated plant genomes, including two green algae. The number of Snf2 ATPases shows considerable variation across plant genomes (17-63 genes. The DRD1, Rad5/16 and Snf2 subfamily members occur most often. Detailed analysis of the plant-specific DRD1 subfamily in related plant genomes shows the occurrence of a complex series of evolutionary events. Notably tomato carries unexpected gene expansions of DRD1 gene members. Most of these genes are expressed in tomato, although at low levels and with distinct tissue or organ specificity. In contrast, the Snf2 subfamily genes tend to be expressed constitutively in tomato. The results underpin and extend the Snf2 subfamily classification, which could help to determine the various functional roles of Snf2 ATPases and to target environmental stress tolerance and yield in future breeding.

  2. Understanding water deficit stress-induced changes in the basic metabolism of higher plants - biotechnologically and sustainably improving agriculture and the ecoenvironment in arid regions of the globe.

    Science.gov (United States)

    Shao, Hong-Bo; Chu, Li-Ye; Jaleel, C Abdul; Manivannan, P; Panneerselvam, R; Shao, Ming-An

    2009-01-01

    Water is vital for plant growth, development and productivity. Permanent or temporary water deficit stress limits the growth and distribution of natural and artificial vegetation and the performance of cultivated plants (crops) more than any other environmental factor. Productive and sustainable agriculture necessitates growing plants (crops) in arid and semiarid regions with less input of precious resources such as fresh water. For a better understanding and rapid improvement of soil-water stress tolerance in these regions, especially in the water-wind eroded crossing region, it is very important to link physiological and biochemical studies to molecular work in genetically tractable model plants and important native plants, and further extending them to practical ecological restoration and efficient crop production. Although basic studies and practices aimed at improving soil water stress resistance and plant water use efficiency have been carried out for many years, the mechanisms involved at different scales are still not clear. Further understanding and manipulating soil-plant water relationships and soil-water stress tolerance at the scales of ecology, physiology and molecular biology can significantly improve plant productivity and environmental quality. Currently, post-genomics and metabolomics are very important in exploring anti-drought gene resources in various life forms, but modern agriculturally sustainable development must be combined with plant physiological measures in the field, on the basis of which post-genomics and metabolomics have further practical prospects. In this review, we discuss physiological and molecular insights and effects in basic plant metabolism, drought tolerance strategies under drought conditions in higher plants for sustainable agriculture and ecoenvironments in arid and semiarid areas of the world. We conclude that biological measures are the bases for the solutions to the issues relating to the different types of

  3. Molecular characterization of UGT94F2 and UGT86C4, two glycosyltransferases from Picrorhiza kurrooa: comparative structural insight and evaluation of substrate recognition.

    Directory of Open Access Journals (Sweden)

    Wajid Waheed Bhat

    Full Text Available Uridine diphosphate glycosyltransferases (UGTs are pivotal in the process of glycosylation for decorating natural products with sugars. It is one of the versatile mechanisms in determining chemical complexity and diversity for the production of suite of pharmacologically active plant natural products. Picrorhiza kurrooa is a highly reputed medicinal herb known for its hepato-protective properties which are attributed to a novel group of iridoid glycosides known as picrosides. Although the plant is well studied in terms of its pharmacological properties, very little is known about the biosynthesis of these important secondary metabolites. In this study, we identified two family-1 glucosyltransferases from P. kurrooa. The full length cDNAs of UGT94F4 and UGT86C4 contained open reading frames of 1455 and 1422 nucleotides, encoding polypeptides of 484 and 473 amino acids respectively. UGT94F2 and UGT86C4 showed differential expression pattern in leaves, rhizomes and inflorescence. To elucidate whether the differential expression pattern of the two Picrorhiza UGTs correlate with transcriptional regulation via their promoters and to identify elements that could be recognized by known iridoid-specific transcription factors, upstream regions of each gene were isolated and scanned for putative cis-regulatory elements. Interestingly, the presence of cis-regulatory elements within the promoter regions of each gene correlated positively with their expression profiles in response to different phytohormones. HPLC analysis of picrosides extracted from different tissues and elicitor-treated samples showed a significant increase in picroside levels, corroborating well with the expression profile of UGT94F2 possibly indicating its implication in picroside biosynthesis. Using homology modeling and molecular docking studies, we provide an insight into the donor and acceptor specificities of both UGTs identified in this study. UGT94F2 was predicted to be an iridoid

  4. Improved plant nitrogen nutrition contributes to higher water use efficiency in tomatoes under alternate partial root-zone irrigation

    DEFF Research Database (Denmark)

    Wang, Yaosheng; Liu, Fulai; Andersen, Mathias Neumann

    2010-01-01

    stomatal conductance during the treatment. At the end of the experiment, N accumulation and 15N recovery was highest in FI, intermediate in PRI and lowest in DI. In addition, PRI plants consistently allocated more N into the upper and middle leaf layers than in the FI and DI treatments. The improved N...... nutrition and distribution in the canopy may indicate that PRI plants have a greater photosynthetic capacity than DI plants; this is confirmed by the observed positive linear relationship between specific leaf N content and δ13C. It is concluded that PRI improves N nutrition and optimises N distribution...

  5. The maize INDETERMINATE1 flowering time regulator defines a highly conserved zinc finger protein family in higher plants

    Directory of Open Access Journals (Sweden)

    Colasanti Joseph

    2006-06-01

    Full Text Available Abstract Background The maize INDETERMINATE1 gene, ID1, is a key regulator of the transition to flowering and the founding member of a transcription factor gene family that encodes a protein with a distinct arrangement of zinc finger motifs. The zinc fingers and surrounding sequence make up the signature ID domain (IDD, which appears to be found in all higher plant genomes. The presence of zinc finger domains and previous biochemical studies showing that ID1 binds to DNA suggests that members of this gene family are involved in transcriptional regulation. Results Comparison of IDD genes identified in Arabidopsis and rice genomes, and all IDD genes discovered in maize EST and genomic databases, suggest that ID1 is a unique member of this gene family. High levels of sequence similarity amongst all IDD genes from maize, rice and Arabidopsis suggest that they are derived from a common ancestor. Several unique features of ID1 suggest that it is a divergent member of the maize IDD family. Although no clear ID1 ortholog was identified in the Arabidopsis genome, highly similar genes that encode proteins with identity extending beyond the ID domain were isolated from rice and sorghum. Phylogenetic comparisons show that these putative orthologs, along with maize ID1, form a group separate from other IDD genes. In contrast to ID1 mRNA, which is detected exclusively in immature leaves, several maize IDD genes showed a broad range of expression in various tissues. Further, Western analysis with an antibody that cross-reacts with ID1 protein and potential orthologs from rice and sorghum shows that all three proteins are detected in immature leaves only. Conclusion Comparative genomic analysis shows that the IDD zinc finger family is highly conserved among both monocots and dicots. The leaf-specific ID1 expression pattern distinguishes it from other maize IDD genes examined. A similar leaf-specific localization pattern was observed for the putative ID1 protein

  6. The light-harvesting complexes of higher plant Photosystem I: Lhca1/4 and Lhca2/3 form two red-emitting heterodimers

    NARCIS (Netherlands)

    Wientjes, I.E.; Croce, R.

    2011-01-01

    The outer antenna of higher-plant PSI (Photosystem I) is composed of four complexes [Lhc (light-harvesting complex) a1-Lhca4] belonging to the light-harvesting protein family. Difficulties in their purification have so far prevented the determination of their properties and most of the knowledge

  7. The light-harvesting complexes of higher-plant Photosystem I : Lhca1/4 and Lhca2/3 form two red-emitting heterodimers

    NARCIS (Netherlands)

    Wientjes, Emilie; Croce, Roberta

    2011-01-01

    The outer antenna of higher-plant PSI (Photosystem I) is composed of four complexes [Lhc (light-harvesting complex) al-Lhca4] belonging to the light-harvesting protein family. Difficulties in their purification have so far prevented the determination of their properties and most of the knowledge

  8. Investigation of the non-photochemical processes in photosynthetic bacteria and higher plants using interference of coherent radiation - a new approach

    Czech Academy of Sciences Publication Activity Database

    Roháček, Karel; Kloz, M.; Bína, David; Batysta, F.; Vácha, František

    2007-01-01

    Roč. 91, 2-3 (2007), s. 301 ISSN 0166-8595. [International Congress of Photosynthesis/14./. 22.07.2007-27.07.2007, Glasgow] Institutional research plan: CEZ:AV0Z50510513 Keywords : Photosynthesis * higher plants Subject RIV: CE - Biochemistry

  9. 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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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. © 2013 German Botanical Society and The Royal Botanical Society of the Netherlands.

  11. Characterization of RbmD (glycosyltransferase in ribostamycin gene cluster) through neomycin production reconstituted from the engineered Streptomyces fradiae BS1.

    Science.gov (United States)

    Nepal, Keshav Kumar; Oh, Tae-Jin; Subba, Bimala; Yoo, Jin Cheol; Sohng, Jae Kyung

    2009-01-31

    Amino acid homology analysis predicted that rbmD, a putative glycosyltransferase from Streptomyces ribosidificus ATCC 21294, has the highest homology with neoD in neomycin biosynthesis. S. fradiae BS1, in which the production of neomycin was abolished, was generated by disruption of the neoD gene in the neomycin producer S. fradiae. The restoration of neomycin by self complementation suggested that there was no polar effect in the mutant. In addition, S. fradiae BS6 was created with complementation by rbmD in S. fradiae BS1, and secondary metabolite analysis by ESI/MS, LC/MS and MS/MS showed the restoration of neomycin production in S. fradiae BS6. These gene inactivation and complementation studies suggested that, like neoD, rbmD functions as a 2-N-acetlyglucosaminyltransferase and demonstrated the potential for the generation of novel aminoglycoside antibiotics using glycosyltransferases in vivo.

  12. Expression, purification, crystallization and preliminary X-ray characterization of a putative glycosyltransferase of the GT-A fold found in mycobacteria

    Energy Technology Data Exchange (ETDEWEB)

    Fulton, Zara; Crellin, Paul K.; Brammananth, Rajini; Zaker-Tabrizi, Leyla; Coppel, Ross L.; Rossjohna, Jamie; Beddoe, Travis (Monash)

    2008-05-28

    Glycosidic bond formation is a ubiquitous enzyme-catalysed reaction. This glycosyltransferase-mediated process is responsible for the biosynthesis of innumerable oligosaccharides and glycoconjugates and is often organism- or cell-specific. However, despite the abundance of genomic information on glycosyltransferases (GTs), there is a lack of structural data for this versatile class of enzymes. Here, the cloning, expression, purification and crystallization of an essential 329-amino-acid (34.8 kDa) putative GT of the classic GT-A fold implicated in mycobacterial cell-wall biosynthesis are reported. Crystals of MAP2569c from Mycobacterium avium subsp. paratuberculosis were grown in 1.6 M monoammonium dihydrogen phosphate and 0.1 M sodium citrate pH 5.5. A complete data set was collected to 1.8 {angstrom} resolution using synchrotron radiation from a crystal belonging to space group P4{sub 1}2{sub 1}2.

  13. Exciton modeling of energy-transfer dynamics in the LHCII complex of higher plants: a Redfield theory approach

    NARCIS (Netherlands)

    Novoderezhkin, V.; Salverda, J.M.; Amerongen, van H.; Grondelle, van R.

    2003-01-01

    We propose an exciton model for the peripheral plant light-harvesting complex LHCII that allows us to explain the absorption (OD) and linear dichroism (LD) spectra, the superradiance (SR), the pump-probe transient absorption (TA), the three-pulse photon echo peak shift (3PEPS), and transient grating

  14. Exciton modeling of energy-transfer dynamics in the LHCII complex of higher plants: A redfield theory approach

    NARCIS (Netherlands)

    Novoderezhkin, V.; Salverda, J.M.; van Amerongen, H.; van Grondelle, R.

    2003-01-01

    We propose an exciton model for the peripheral plant light-harvesting complex LHCII that allows us to explain the absorption (OD) and linear dichroism (LD) spectra, the superradiance (SR), the pump-probe transient absorption (TA), the three-pulse photon echo peak shift (3PEPS), and transient grating

  15. The chromosomal distributions of Ty1-copia group retrotransposable elements in higher plants and their implications for genome evolution

    Science.gov (United States)

    J.S. (Pat) Heslop-Harrison; Andrea Brandes; Shin Taketa; Thomas Schmidt; Alexander V. Vershinin; Elena G. Alkhimova; Anette Kamm; Robert L. Doudrick; . [and others

    1997-01-01

    Retrotransposons make up a major fraction - sometimes more than 40% - of all plant genomes investigated so far. We have isolated the reverse transcriptase domains of theTyl-copia group elements from several species, ranging in genome size from some 100 Mbp to 23,000 Mbp, and determined the distribution patterns of these retrotransposons on metaphase chromosomes and...

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

    Science.gov (United States)

    Autar K. Mattoo; Subhash C. Minocha; Rakesh Minocha; Avtar K. Handa

    2010-01-01

    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 intracellular levels are tightly regulated, which have made it difficult to...

  17. Novel staphylococcal glycosyltransferases SdgA and SdgB mediate immunogenicity and protection of virulence-associated cell wall proteins.

    Directory of Open Access Journals (Sweden)

    Wouter L W Hazenbos

    Full Text Available Infection of host tissues by Staphylococcus aureus and S. epidermidis requires an unusual family of staphylococcal adhesive proteins that contain long stretches of serine-aspartate dipeptide-repeats (SDR. The prototype member of this family is clumping factor A (ClfA, a key virulence factor that mediates adhesion to host tissues by binding to extracellular matrix proteins such as fibrinogen. However, the biological siginificance of the SDR-domain and its implication for pathogenesis remain poorly understood. Here, we identified two novel bacterial glycosyltransferases, SdgA and SdgB, which modify all SDR-proteins in these two bacterial species. Genetic and biochemical data demonstrated that these two glycosyltransferases directly bind and covalently link N-acetylglucosamine (GlcNAc moieties to the SDR-domain in a step-wise manner, with SdgB appending the sugar residues proximal to the target Ser-Asp repeats, followed by additional modification by SdgA. GlcNAc-modification of SDR-proteins by SdgB creates an immunodominant epitope for highly opsonic human antibodies, which represent up to 1% of total human IgG. Deletion of these glycosyltransferases renders SDR-proteins vulnerable to proteolysis by human neutrophil-derived cathepsin G. Thus, SdgA and SdgB glycosylate staphylococcal SDR-proteins, which protects them against host proteolytic activity, and yet generates major eptopes for the human anti-staphylococcal antibody response, which may represent an ongoing competition between host and pathogen.

  18. Glycosyltransferases as marker genes for the quantitative polymerase chain reaction-based detection of circulating tumour cells from blood samples of patients with breast cancer undergoing adjuvant therapy.

    Science.gov (United States)

    Kölbl, Alexandra C; Hiller, Roman A; Ilmer, Mathias; Liesche, Friederike; Heublein, Sabine; Schröder, Lennard; Hutter, Stefan; Friese, Klaus; Jeschke, Udo; Andergassen, Ulrich

    2015-08-01

    Altered glycosylation is a predominant feature of tumour cells; it serves for cell adhesion and detachment, respectively, and facilitates the immune escape of these cells. Therefore changes in the expression of glycosyltransferase genes could help to identify circulating tumour cells (CTCs) in the blood samples of cancer patients using a quantitative polymerase chain reaction (PCR) approach. Blood samples of healthy donors were inoculated with certain numbers of established breast cancer cell line cells, thus creating a model system. These samples were analysed by quantitative PCR for the expression of six different glycosyltransferase genes. The three genes with the best results in the model system were consecutively applied to samples from adjuvant breast cancer patients and of healthy donors. FUT3 and GALNT6 showed the highest increase in relative expression, while GALNT6 and ST3GAL3 were the first to reach statistically significant different ∆CT-values comparing the sample with and without addition of tumour cells. These three genes were applied to patient samples, but did not show any significant results that may suggest the presence of CTCs in the blood. Although the relative expression of some of the glycosyltransferase genes exhibited reasonable results in the model system, their application to breast cancer patient samples will have to be further improved, e.g. by co-analysis of patient blood samples by gold-standard methods.

  19. Expression, purification, crystallization and preliminary X-ray characterization of a putative glycosyltransferase of the GT-A fold found in mycobacteria

    Energy Technology Data Exchange (ETDEWEB)

    Fulton, Zara [The Protein Crystallography Unit, Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, Victoria 3800 (Australia); Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, Clayton, Victoria 3800 (Australia); Crellin, Paul K.; Brammananth, Rajini [Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, Clayton, Victoria 3800 (Australia); Department of Microbiology, School of Biomedical Sciences, Monash University, Clayton, Victoria 3800 (Australia); Zaker-Tabrizi, Leyla [The Protein Crystallography Unit, Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, Victoria 3800 (Australia); Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, Clayton, Victoria 3800 (Australia); Coppel, Ross L. [Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, Clayton, Victoria 3800 (Australia); Department of Microbiology, School of Biomedical Sciences, Monash University, Clayton, Victoria 3800 (Australia); Rossjohn, Jamie, E-mail: jamie.rossjohn@med.monash.edu.au; Beddoe, Travis, E-mail: jamie.rossjohn@med.monash.edu.au [The Protein Crystallography Unit, Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, Victoria 3800 (Australia); Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, Clayton, Victoria 3800 (Australia)

    2008-05-01

    MAP2569c from M. avium subsp. paratuberculosis, a putative glycosyltransferase implicated in mycobacterial cell-wall biosynthesis, was cloned, expressed, purified and crystallized. X-ray diffraction data were collected to 1.8 Å resolution. Glycosidic bond formation is a ubiquitous enzyme-catalysed reaction. This glycosyltransferase-mediated process is responsible for the biosynthesis of innumerable oligosaccharides and glycoconjugates and is often organism- or cell-specific. However, despite the abundance of genomic information on glycosyltransferases (GTs), there is a lack of structural data for this versatile class of enzymes. Here, the cloning, expression, purification and crystallization of an essential 329-amino-acid (34.8 kDa) putative GT of the classic GT-A fold implicated in mycobacterial cell-wall biosynthesis are reported. Crystals of MAP2569c from Mycobacterium avium subsp. paratuberculosis were grown in 1.6 M monoammonium dihydrogen phosphate and 0.1 M sodium citrate pH 5.5. A complete data set was collected to 1.8 Å resolution using synchrotron radiation from a crystal belonging to space group P4{sub 1}2{sub 1}2.

  20. Expression, purification, crystallization and preliminary X-ray characterization of a putative glycosyltransferase of the GT-A fold found in mycobacteria

    International Nuclear Information System (INIS)

    Fulton, Zara; Crellin, Paul K.; Brammananth, Rajini; Zaker-Tabrizi, Leyla; Coppel, Ross L.; Rossjohn, Jamie; Beddoe, Travis

    2008-01-01

    MAP2569c from M. avium subsp. paratuberculosis, a putative glycosyltransferase implicated in mycobacterial cell-wall biosynthesis, was cloned, expressed, purified and crystallized. X-ray diffraction data were collected to 1.8 Å resolution. Glycosidic bond formation is a ubiquitous enzyme-catalysed reaction. This glycosyltransferase-mediated process is responsible for the biosynthesis of innumerable oligosaccharides and glycoconjugates and is often organism- or cell-specific. However, despite the abundance of genomic information on glycosyltransferases (GTs), there is a lack of structural data for this versatile class of enzymes. Here, the cloning, expression, purification and crystallization of an essential 329-amino-acid (34.8 kDa) putative GT of the classic GT-A fold implicated in mycobacterial cell-wall biosynthesis are reported. Crystals of MAP2569c from Mycobacterium avium subsp. paratuberculosis were grown in 1.6 M monoammonium dihydrogen phosphate and 0.1 M sodium citrate pH 5.5. A complete data set was collected to 1.8 Å resolution using synchrotron radiation from a crystal belonging to space group P4 1 2 1 2

  1. In situ DNA-RNA hybridization using in vitro 125I-labeled ribosomal RNA of higher plant

    International Nuclear Information System (INIS)

    Sato, Seiichi; Kikuchi, Tadatoshi; Ishida, M.R.; Tanaka, Ryuso.

    1975-01-01

    In situ hybridization using 125 I-labeled ribosomal RNA was applied to plant cells. Cytoplasmic 25 s rRNA, which was eluted from acrylamide gels after electrophoretic separation, was labeled in vitro with carrier-free 125 I and hybridized with the interphase nuclei in root tips of Vicia faba. In most of the preparations, the nucleoli were more heavily labeled than the other regions within nuclei, and several types of grain distribution were observed on the nucleoli. From these results, it was confirmed that in situ hybridization using 125 I-labeled rRNA can be used very effectively to detect the annealing sites of different molecular species of rRNA within the nuclei of plant cells, for which it is not as easy to obtain high specific radioactive rRNA in vivo as it is in the case of cultured animal cells. (auth.)

  2. Mechanisms to Detoxify Selected Organic Contaminants in Higher Plants and Microbes, and Their Potential Use in Landscape Management

    Science.gov (United States)

    2004-10-01

    growing tissues and reproductive organs. The herbicide 2,4-D and defoliant 2,4,5-T are absorbed by leaves and translocated basipetally and acropetally...into motion by the superior affinity of the xenobiotic for the enzyme compared to its natural substrates. When plants grow in a medium that contains...al. 1992). The tentative mechanism of the phenoloxidase action is based on results obtained for mushroom ( Agaricus bisporus) tyrosinase, a typical

  3. Gas exchange at whole plant level shows that a less conservative water use is linked to a higher performance in three ecologically distinct pine species

    Science.gov (United States)

    Salazar-Tortosa, D.; Castro, J.; Rubio de Casas, R.; Viñegla, B.; Sánchez-Cañete, E. P.; Villar-Salvador, P.

    2018-04-01

    Increasing temperatures and decreasing precipitation in large areas of the planet as a consequence of global warming will affect plant growth and survival. However, the impact of climatic conditions will differ across species depending on their stomatal response to increasing aridity, as this will ultimately affect the balance between carbon assimilation and water loss. In this study, we monitored gas exchange, growth and survival in saplings of three widely distributed European pine species (Pinus halepensis, P. nigra and P. sylvestris) with contrasting distribution and ecological requirements in order to ascertain the relationship between stomatal control and plant performance. The experiment was conducted in a common garden environment resembling rainfall and temperature conditions that two of the three species are expected to encounter in the near future. In addition, gas exchange was monitored both at the leaf and at the whole-plant level using a transient-state closed chamber, which allowed us to model the response of the whole plant to increased air evaporative demand (AED). P. sylvestris was the species with lowest survival and performance. By contrast, P. halepensis showed no mortality, much higher growth (two orders of magnitude), carbon assimilation (ca. 14 fold higher) and stomatal conductance and water transpiration (ca. 4 fold higher) than the other two species. As a consequence, P. halepensis exhibited higher values of water-use efficiency than the rest of the species even at the highest values of AED. Overall, the results strongly support that the weaker stomatal control of P. halepensis, which is linked to lower stem water potential, enabled this species to maximize carbon uptake under drought stress and ultimately outperform the more water conservative P. nigra and P. sylvestris. These results suggest that under a hotter drought scenario P. nigra and P. sylvestris would very likely suffer increased mortality, whereas P. halepensis could maintain

  4. Regulation of plant cells, cell walls and development by mechanical signals

    Energy Technology Data Exchange (ETDEWEB)

    Meyerowitz, Elliot M. [California Inst. of Technology (CalTech), Pasadena, CA (United States)

    2016-06-14

    The overall goal of the revised scope of work for the final year of funding was to characterize cell wall biosynthesis in developing cotyledons and in the shoot apical meristem of Arabidopsis thaliana, as a way of learning about developmental control of cell wall biosynthesis in plants, and interactions between cell wall biosynthesis and the microtubule cytoskeleton. The proposed work had two parts – to look at the effect of mutation in the SPIRAL2 gene on microtubule organization and reorganization, and to thoroughly characterize the glycosyltransferase genes expressed in shoot apical meristems by RNA-seq experiments, by in situ hybridization of the RNAs expressed in the meristem, and by antibody staining of the products of the glycosyltransferases in meristems. Both parts were completed; the spiral2 mutant was found to speed microtubule reorientation after ablation of adjacent cells, supporting our hypothesis that reorganization correlates with microtubule severing, the rate of which is increased by the mutation. The glycosyltransferase characterization was completed and published as Yang et al. (2016). Among the new things learned was that primary cell wall biosynthesis is strongly controlled both by cell type, and by stage of cell cycle, implying not only that different, even adjacent, cells can have different sugar linkages in their (nonshared) walls, but also that a surprisingly large proportion of glycosyltransferases is regulated in the cell cycle, and therefore that the cell cycle regulates wall maturation to a degree previously unrecognized.

  5. Base substitution mutations in uridinediphosphate-dependent glycosyltransferase 76G1 gene of Stevia rebaudiana causes the low levels of rebaudioside A: mutations in UGT76G1, a key gene of steviol glycosides synthesis.

    Science.gov (United States)

    Yang, Yong-Heng; Huang, Su-Zhen; Han, Yu-Lin; Yuan, Hai-Yan; Gu, Chun-Sun; Zhao, Yan-Hai

    2014-07-01

    Steviol glycosides, extracted from the leaves of Stevia rebaudiana (Bert) Bertoni, are calorie-free sugar substitute of natural origin with intensely sweet (Boileau et al., 2012). Stevioside and rebaudioside A are the two main kinds of the diterpenic glycosides. We analyzed the concentration of stevioside and rebaudioside A in Stevia leaves of about 500 samples (hybrid progenies) and discovered a mutation plant "Z05" with very low levels of rebaudioside A. Because UGT76G1, a uridinediphosphate-dependent glycosyltransferases, is responsible for the conversion from stevioside to rebaudioside A (Richman et al., 2005), so mutation identification was done by sequencing the candidate gene, UGT76G1. In this study molecular analysis of two strains revealed a heterozygotic nonsense mutation of c.389T > G (p.L121X) in UGT76G1. Meanwhile, we found some amino acid substitutions significant change the protein structure. And the difference of enzyme activity between two strains proved the lack of functionality of UGT76G1 of the mutation "Z05". So the nonsense mutation and amino acid substitution mutation resulted in the low levels of rebaudioside A. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

    Rosenthal, Cindy [Department of Pharmaceutical Biology, Institute of Pharmacy, Johannes Gutenberg-University Mainz, Staudinger Weg 5, D-55099 Mainz (Germany); Mueller, Uwe [Berliner Elektronenspeicherring-Gesellschaft für Synchrotronstrahlung mbH, Albert-Einstein-Strasse 15, D-12489 Berlin (Germany); Panjikar, Santosh [European Molecular Biology Laboratory Hamburg, Outstation Deutsches Elektronen-Synchrotron, Notkestrasse 85, D-22603 Hamburg (Germany); Sun, Lianli [Department of Pharmaceutical Biology, Institute of Pharmacy, Johannes Gutenberg-University Mainz, Staudinger Weg 5, D-55099 Mainz (Germany); Department of TCM and Natural Drug Research, College of Pharmaceutical Sciences, 513 Zijingang Campus, Zhejiang University, 310058 Hangzhou (China); Ruppert, Martin [Department of Pharmaceutical Biology, Institute of Pharmacy, Johannes Gutenberg-University Mainz, Staudinger Weg 5, D-55099 Mainz (Germany); Zhao, Yu [Department of TCM and Natural Drug Research, College of Pharmaceutical Sciences, 513 Zijingang Campus, Zhejiang University, 310058 Hangzhou (China); Stöckigt, Joachim [Department of Pharmaceutical Biology, Institute of Pharmacy, Johannes Gutenberg-University Mainz, Staudinger Weg 5, D-55099 Mainz (Germany); Department of TCM and Natural Drug Research, College of Pharmaceutical Sciences, 513 Zijingang Campus, Zhejiang University, 310058 Hangzhou (China)

    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.

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

    International Nuclear Information System (INIS)

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

    2006-01-01

    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 1 and diffract to 2.0 Å, with unit-cell parameters a = 58.9, b = 93.0, c = 143.4 Å

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

    Energy Technology Data Exchange (ETDEWEB)

    Hashimoto, T. [Kobe Women`s Univ., Higashisuma (Japan)

    1994-12-31

    It 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.

  9. Higher water plants in a lake contaminated with radionuclides: composition, distribution, reserves and accumulation of Cs-137

    International Nuclear Information System (INIS)

    Pavlyutin, A.P.; Babitskij, V.A.

    1996-01-01

    Species composition, specials distribution, seasonal pattern and accumulation of cesium-137 by aquatic plants had been investigated in the small not flowing meso trophic lake (Belarus) during vegetative season of 1993. Macrophyte phytomass storage is equal 10,56 t, and mass of its roots is 4.28 t of dry weight. Cesium-137 stock's in green mass and macrophytes roots are equal to 108.6 and 96.4 MBK respectively. Total accumulation of cesium-137 by macrophyte constituted 5% from its stock in the whole lake water mass

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

    CSIR Research Space (South Africa)

    Thwala, Melusi

    2016-01-01

    Full Text Available TiO2). Concentration dependent accumulation of Ti was reported after 7 d exposure of Lemna minor to 0.01-5 mg/L nTiO2 [74]. Approximately an average of 70 mg/kg whole plant Ti was recorded at the highest exposure concentration compared to 0.37 mg... differ between species [72] was support d by the findings of Glenn et al. [45]. Using electron microscopy techniques, Li et al. [74] found agglomerates of nTiO2 adsorbed onto L. minor fronds but no internalisation was evident, and concluded...

  11. Structure and Mechanism of Staphylococcus aureus TarS, the Wall Teichoic Acid β-glycosyltransferase Involved in Methicillin Resistance.

    Directory of Open Access Journals (Sweden)

    Solmaz Sobhanifar

    2016-12-01

    Full Text Available In recent years, there has been a growing interest in teichoic acids as targets for antibiotic drug design against major clinical pathogens such as Staphylococcus aureus, reflecting the disquieting increase in antibiotic resistance and the historical success of bacterial cell wall components as drug targets. It is now becoming clear that β-O-GlcNAcylation of S. aureus wall teichoic acids plays a major role in both pathogenicity and antibiotic resistance. Here we present the first structure of S. aureus TarS, the enzyme responsible for polyribitol phosphate β-O-GlcNAcylation. Using a divide and conquer strategy, we obtained crystal structures of various TarS constructs, mapping high resolution overlapping N-terminal and C-terminal structures onto a lower resolution full-length structure that resulted in a high resolution view of the entire enzyme. Using the N-terminal structure that encapsulates the catalytic domain, we furthermore captured several snapshots of TarS, including the native structure, the UDP-GlcNAc donor complex, and the UDP product complex. These structures along with structure-guided mutants allowed us to elucidate various catalytic features and identify key active site residues and catalytic loop rearrangements that provide a valuable platform for anti-MRSA drug design. We furthermore observed for the first time the presence of a trimerization domain composed of stacked carbohydrate binding modules, commonly observed in starch active enzymes, but adapted here for a poly sugar-phosphate glycosyltransferase.

  12. Engineered jadomycin analogues with altered sugar moieties revealing JadS as a substrate flexible O-glycosyltransferase.

    Science.gov (United States)

    Li, Liyuan; Pan, Guohui; Zhu, Xifen; Fan, Keqiang; Gao, Wubin; Ai, Guomin; Ren, Jinwei; Shi, Mingxin; Olano, Carlos; Salas, José A; Yang, Keqian

    2017-07-01

    Glycosyltransferases (GTs)-mediated glycodiversification studies have drawn significant attention recently, with the goal of generating bioactive compounds with improved pharmacological properties by diversifying the appended sugars. The key to achieving glycodiversification is to identify natural and/or engineered flexible GTs capable of acting upon a broad range of substrates. Here, we report the use of a combinatorial biosynthetic approach to probe the substrate flexibility of JadS, the GT in jadomycin biosynthesis, towards different non-native NDP-sugar substrates, enabling us to identify six jadomycin B analogues with different sugar moieties. Further structural engineering by precursor-directed biosynthesis allowed us to obtain 11 new jadomycin analogues. Our results for the first time show that JadS is a flexible O-GT that can utilize both L- and D- sugars as donor substrates, and tolerate structural changes at the C2, C4 and C6 positions of the sugar moiety. JadS may be further exploited to generate novel glycosylated jadomycin molecules in future glycodiversification studies.

  13. [A novel M142T mutation in the B glycosyltransferase gene associated with B3 variant in Chinese].

    Science.gov (United States)

    Xu, Xian-guo; Hong, Xiao-zhen; Liu, Ying; Zhu, Fa-ming; Lv, Hang-jun; Yan, Li-xing

    2009-06-01

    To investigate the molecular genetic basis of the B3 variant of ABO blood group system with mixed-field hemagglutination in Chinese. Serological techniques were performed to characterize the erythrocyte phenotype of two discrepant samples. A sequential agglutination method and 13 short tandem repeat (STR) loci were tested to exclude the possibility of exogenous or endogenous DNA chimera. Mutations in exons 6 and 7, including partial intron of the ABO gene, were screened by polymerase chain reaction and DNA sequencing. Haplotypes of the two individuals were also analyzed by sequencing. A mixed-field hemagglutination of RBCs with anti-B and anti-AB antibodies was detected in the two unrelated individuals. Exogenous ABO-incompatible RBC transfusion and endogenous genetic chimera were excluded by sequential agglutination method and STR. The ABO phenotypes of the two individuals were classified as A1B3 according to the ABO subgroup definition. The sequence region from intron 5 to 3'-UTR of the B allele was identical to that of ABO*B101 allele, except for a T to C substitution at nucleotide position 425 in exon 7. This substitution resulted in an amino acid change of M142T in the B glycosyltransferase. A novel B allele with 425T>C substitution resulting in B3 subgroup was identified in two Chinese individuals.

  14. [Gene deletion and functional analysis of the heptyl glycosyltransferase (waaF) gene in Vibrio parahemolyticus O-antigen cluster].

    Science.gov (United States)

    Zhao, Feng; Meng, Songsong; Zhou, Deqing

    2016-02-04

    To construct heptyl glycosyltransferase gene II (waaF) gene deletion mutant of Vibrio parahaemolyticus, and explore the function of the waaF gene in Vibrio parahaemolyticus. The waaF gene deletion mutant was constructed by chitin-based transformation technology using clinical isolates, and then the growth rate, morphology and serotypes were identified. The different sources (O3, O5 and O10) waaF gene complementations were constructed through E. coli S17λpir strains conjugative transferring with Vibrio parahaemolyticus, and the function of the waaF gene was further verified by serotypes. The waaF gene deletion mutant strain was successfully constructed and it grew normally. The growth rate and morphology of mutant were similar with the wild type strains (WT), but the mutant could not occurred agglutination reaction with O antisera. The O3 and O5 sources waaF gene complementations occurred agglutination reaction with O antisera, but the O10 sources waaF gene complementations was not. The waaF gene was related with O-antigen synthesis and it was the key gene of O-antigen synthesis pathway in Vibrio parahaemolyticus. The function of different sources waaF gene were not the same.

  15. Scaling down the size and increasing the throughput of glycosyltransferase assays: activity changes on stem cell differentiation.

    Science.gov (United States)

    Patil, Shilpa A; Chandrasekaran, E V; Matta, Khushi L; Parikh, Abhirath; Tzanakakis, Emmanuel S; Neelamegham, Sriram

    2012-06-15

    Glycosyltransferases (glycoTs) catalyze the transfer of monosaccharides from nucleotide-sugars to carbohydrate-, lipid-, and protein-based acceptors. We examined strategies to scale down and increase the throughput of glycoT enzymatic assays because traditional methods require large reaction volumes and complex chromatography. Approaches tested used (i) microarray pin printing, an appropriate method when glycoT activity was high; (ii) microwells and microcentrifuge tubes, a suitable method for studies with cell lysates when enzyme activity was moderate; and (iii) C(18) pipette tips and solvent extraction, a method that enriched reaction product when the extent of reaction was low. In all cases, reverse-phase thin layer chromatography (RP-TLC) coupled with phosphorimaging quantified the reaction rate. Studies with mouse embryonic stem cells (mESCs) demonstrated an increase in overall β(1,3)galactosyltransferase and α(2,3)sialyltransferase activity and a decrease in α(1,3)fucosyltransferases when these cells differentiate toward cardiomyocytes. Enzymatic and lectin binding data suggest a transition from Lewis(x)-type structures in mESCs to sialylated Galβ1,3GalNAc-type glycans on differentiation, with more prominent changes in enzyme activity occurring at later stages when embryoid bodies differentiated toward cardiomyocytes. Overall, simple, rapid, quantitative, and scalable glycoT activity analysis methods are presented. These use a range of natural and synthetic acceptors for the analysis of complex biological specimens that have limited availability. Copyright © 2012 Elsevier Inc. All rights reserved.

  16. Comparative studies on the photosynthesis of higher plants, 4. Further studies on the photosynthetic sugar formation pathway in C/sub 4/-plants

    Energy Technology Data Exchange (ETDEWEB)

    Imai, H [National Inst. of Agricultural Sciences, Tokyo (Japan); Iwai, Sumio; Yamada, Yoshio

    1975-03-01

    In this paper, studies were carried out to confirm whether carbon atoms except C-4 of C/sub 4/-compounds were involved in the photosynthetic sugar formation in C/sub 4/ plants. In feeding of uniformly-labeled malate to maize leaves, sugar formation under aerobic conditions was 3 times as large as that under anaerobic conditions. There was no detectable difference in the amount of activity in the sugar formed from ..beta..-carboxyl-labeled malate between aerobic and anaerobic conditions; however. Under anaerobic conditions, sugar was formed from alanine-1-/sup 14/C in maize but not in rice leaves. Sugar formation of this case might have occurred by the direct conversion of pyruvate to sugar via PEP and PGA. From these results, we assume that the following three pathways function cooperatively in the photosynthetic sugar formation in C/sub 4/-plants. 1) One carbon atom at number 4 in C/sub 4/-dicarboxylic acid is transferred to RuDP, resulting in the formation of PGA and this is metabolized into sugar. 2) After transferring C-4 of C/sub 4/-dicarboxylic acid, the remaining C/sub 3/-compound is introduced into the TCA cycle and completely degradated there, and thus-produced CO/sub 2/ is refixed by PEP carboxylase in the mesophyll and metabolized into sugar the same pathway as in atmospheric CO/sub 2/ fixation. 3) The remaining C/sub 3/-compound is directly converted to PEP and then to sugar via PGA.

  17. Bi-functional glycosyltransferases catalyze both extension and termination of pectic galactan oligosaccharides

    DEFF Research Database (Denmark)

    Laursen, Tomas; Stonebloom, Solomon H; Pidatala, Venkataramana R

    2018-01-01

    . Transfer of Arap to galactan prevents further addition of galactose residues, resulting in a lower degree of polymerization. We show that this dual activity occurs both in vitro and in vivo. The herein described bi-functionality of AtGALS1 may suggest that plants can produce the incredible structural...

  18. Towards systems biology of the gravity response of higher plants -multiscale analysis of Arabidopsis thaliana root growth

    Science.gov (United States)

    Palme, Klaus; Aubry, D.; Bensch, M.; Schmidt, T.; Ronneberger, O.; Neu, C.; Li, X.; Wang, H.; Santos, F.; Wang, B.; Paponov, I.; Ditengou, F. A.; Teale, W. T.; Volkmann, D.; Baluska, F.; Nonis, A.; Trevisan, S.; Ruperti, B.; Dovzhenko, A.

    Gravity plays a fundamental role in plant growth and development. Up to now, little is known about the molecular organisation of the signal transduction cascades and networks which co-ordinate gravity perception and response. By using an integrated systems biological approach, a systems analysis of gravity perception and the subsequent tightly-regulated growth response is planned in the model plant Arabidopsis thaliana. This approach will address questions such as: (i) what are the components of gravity signal transduction pathways? (ii) what are the dynamics of these components? (iii) what is their spatio-temporal regulation in different tis-sues? Using Arabidopsis thaliana as a model-we use root growth to obtain insights in the gravity response. New techniques enable identification of the individual genes affected by grav-ity and further integration of transcriptomics and proteomics data into interaction networks and cell communication events that operate during gravitropic curvature. Using systematic multiscale analysis we have identified regulatory networks consisting of transcription factors, the protein degradation machinery, vesicle trafficking and cellular signalling during the gravire-sponse. We developed approach allowing to incorporate key features of the root system across all relevant spatial and temporal scales to describe gene-expression patterns and correlate them with individual gene and protein functions. Combination of high-resolution microscopy and novel computational tools resulted in development of the root 3D model in which quantitative descriptions of cellular network properties and of multicellular interactions important in root growth and gravitropism can be integrated for the first time.

  19. Diets higher in animal and plant protein are associated with lower adiposity and do not impair kidney function in US adults.

    Science.gov (United States)

    Berryman, Claire E; Agarwal, Sanjiv; Lieberman, Harris R; Fulgoni, Victor L; Pasiakos, Stefan M

    2016-09-01

    Higher-protein diets are associated with decreased adiposity and greater HDL cholesterol than lower protein diets. Whether these benefits can be attributed to a specific protein source (i.e., nondairy animal, dairy, or plant) is unknown, and concerns remain regarding the impact of higher-protein diets on kidney function. The objective of this study was to evaluate trends of protein source on markers of cardiometabolic disease risk and kidney function in US adults. Total, nondairy animal, dairy, and plant protein intake were estimated with the use of 24-h recall data from NHANES 2007-2010 (n = 11,111; ≥19 y). Associations between source-specific protein intake and health outcomes were determined with the use of models that adjusted for sex, race and ethnicity, age, physical activity, poverty-to-income ratio, individual intake (grams per kilogram) for each of the other 2 protein sources, body mass index (BMI) (except for weight-related variables), and macronutrient (carbohydrate, fiber, and total and saturated fat) intake. Mean ± SE total protein intake was 82.3 ± 0.8 g/d (animal: 37.4 ± 0.5 g/d; plant: 24.7 ± 0.3 g/d; and dairy: 13.4 ± 0.3 g/d). Both BMI and waist circumference were inversely associated [regression coefficient (95% CI)] with animal [-0.199 (-0.265, -0.134), P protein intake. Blood urea nitrogen concentrations increased across deciles for animal [0.313 (0.248, 0.379), P protein intake. Glomerular filtration rate and blood creatinine were not associated with intake of any protein source. Diets higher in plant and animal protein, independent of other dietary factors, are associated with cardiometabolic benefits, particularly improved central adiposity, with no apparent impairment of kidney function. © 2016 American Society for Nutrition.

  20. Mechanism of radiation tolerance in higher plants. Radiation damage of DNA in cultured tobacco BY-2 cells and implication from its repair process

    International Nuclear Information System (INIS)

    Yokota, Yuichiro; Narumi, Issay; Funayama, Tomoo; Kobayashi, Yasuhiko; Tanaka, Jun; Inoue, Masayoshi

    2007-01-01

    This paper describes the mechanism of radiation tolerance at the cellular level in higher plants, of which fundamental study basis is rather poor, in cultured cells in the title (BY-2 cells, Nicotiana tabacum L., allotetraploid). When compared with LD 50 of radiation in higher animals (2.4-8.6 Gy), higher plants are generally tolerant to radiation (known LD 50 , >360-2000 Gy). Authors have made unicellular BY-2 cells (protoplasts) by enzyme treatment to see their colony forming ability (CFA) and have found those cells are also resistant to radiation: D 10 (10% CFA dose) (Gy) is found to be 8.2-47.2 by radiation with various linear energy transfer (LET)s like gamma ray and heavy ion beams, in contrast to human D 10 (1.17-8.12, by X-ray and carbon beam). Double strand break (DSB) of DNA by radiation per one BY-2 cell initially occurs 7-10 times more frequently than mammalian cells (CHO-K1). However, DSB repair in BY-2 cells is found only as efficient as in mammalian cells: a slow repair relative to DSB number. Checkpoint mechanism of DNA damage is found poorly working in BY-cells, which results in frequent chromosome aberration like micronucleus. Authors consider that, for an herbaceous plant, to precede the cell cycle rather than to recover from the genomic instability can be profitable for growing more rapidly to have more sunlight energy than other individuals. Improvement of plants by gene technological approach with such a mean as mutation by radiation is conceivably important from aspects of food supply and of ecological environment. (R.T.)

  1. Generation of poly-β-hydroxybutyrate from acetate in higher plants: Detection of acetoacetyl CoA reductase- and PHB synthase- activities in rice.

    Science.gov (United States)

    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. Copyright © 2016 Elsevier GmbH. All rights reserved.

  2. AMT1;1 transgenic rice plants with enhanced NH4(+) permeability show superior growth and higher yield under optimal and suboptimal NH4(+) conditions.

    Science.gov (United States)

    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.

  3. AMT1;1 transgenic rice plants with enhanced NH4 + permeability show superior growth and higher yield under optimal and suboptimal NH4 + conditions

    Science.gov (United States)

    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

  4. Biochemical studies on the effect of fluoride on higher plants. 3. The effect of fluoride on dark carbon dioxide fixation

    Energy Technology Data Exchange (ETDEWEB)

    Yang, S F; Miller, G W

    1963-01-01

    Dark CO/sub 2/ fixation and phosphoenolpyruvate-carboxylase activity were studied in fluoride-necrotic and control soya-bean leaves. Necrotic leaves had a higher rate of dark CO/sub 2/ fixation than control leaves both in vivo and in vitro (phosphoenolpyruvate carboxylase). Results suggested that the accumulation of organic acids and amino acids in necrotic leaves resulted from an increased rate of dark CO/sub 2/ fixation. The possible role of fluoride in stimulating the carboxylation and its implication to necrosis are discussed.

  5. Isotopic niche variation in a higher trophic level ectotherm: highlighting the role of succulent plants in desert food webs.

    Directory of Open Access Journals (Sweden)

    Miguel Delibes

    Full Text Available 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(13C, δ(15N. 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(13C-δ(15N 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.

  6. Isotopic Niche Variation in a Higher Trophic Level Ectotherm: Highlighting the Role of Succulent Plants in Desert Food Webs

    Science.gov (United States)

    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

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

    Science.gov (United States)

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

    2006-01-01

    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 C2221 and diffract to 2.0 Å, with unit-cell parameters a = 58.9, b = 93.0, c = 143.4 Å. PMID:17142919

  8. Stearoyl-acyl-carrier-protein desaturase from higher plants is structurally unrelated to the animal and fungal homologs

    International Nuclear Information System (INIS)

    Shanklin, J.; Somerville, C.

    1991-01-01

    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 Δ 9 desaturase is developmentally regulated

  9. Integrated process design for biocatalytic synthesis by a Leloir Glycosyltransferase: UDP-glucose production with sucrose synthase.

    Science.gov (United States)

    Schmölzer, Katharina; Lemmerer, Martin; Gutmann, Alexander; Nidetzky, Bernd

    2017-04-01

    Nucleotide sugar-dependent ("Leloir") glycosyltransferases (GTs), represent a new paradigm for the application of biocatalytic glycosylations to the production of fine chemicals. However, it remains to be shown that GT processes meet the high efficiency targets of industrial biotransformations. We demonstrate in this study of uridine-5'-diphosphate glucose (UDP-glc) production by sucrose synthase (from Acidithiobacillus caldus) that a holistic process design, involving coordinated development of biocatalyst production, biotransformation, and downstream processing (DSP) was vital for target achievement at ∼100 g scale synthesis. Constitutive expression in Escherichia coli shifted the recombinant protein production mainly to the stationary phase and enhanced the specific enzyme activity to a level (∼480 U/g cell dry weight ) suitable for whole-cell biotransformation. The UDP-glc production had excellent performance metrics of ∼100 g product /L, 86% yield (based on UDP), and a total turnover number of 103 g UDP-glc /g cell dry weight at a space-time yield of 10 g/L/h. Using efficient chromatography-free DSP, the UDP-glc was isolated in a single batch with ≥90% purity and in 73% isolated yield. Overall, the process would allow production of ∼0.7 kg of isolated product/L E. coli bioreactor culture, thus demonstrating how integrated process design promotes the practical use of a GT conversion. Biotechnol. Bioeng. 2017;114: 924-928. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  10. [Effect of high magnesium ion concentration on the electron transport rate and proton exchange in thylakoid membranes in higher plants].

    Science.gov (United States)

    Ignat'ev, A R; Khorobrykh, S A; Ivanov, B N

    2001-01-01

    The effects of magnesium ion concentration on the rate of electron transport in isolated pea thylakoids were investigated in the pH range from 4.0 up to 8.0. In the absence of magnesium ions in the medium and in the presence of 5 mM MgCl2 in the experiments not only without added artificial acceptors but also with ferricyanide or methylviologen as an acceptor, this rate had a well-expressed maximum at pH 5.0. It was shown that, after depression to minimal values at pH 5.5-6.5, it gradually rose with increasing pH. An increase in magnesium ion concentration up to 20 mM essentially affected the electron transfer rate: it decreased somewhat at pH 4.0-5.0 but increased at higher pH values. At this magnesium ion concentration, the maximum rate was at pH 6.0-6.5 and the minimum, at pH 7.0. Subsequent rise upon increasing pH to 8.0 was expressed more sharply. The influence of high magnesium ion concentration on the rate of electron transport was not observed in the presence of gramicidin D. It was found that without uncoupler, the changes in the electron transfer rate under the influence of magnesium ions correlated to the changes in the first-order rate constant of the proton efflux from thylakoids. It is supposed that the change in the ability of thylakoids to keep protons by the action of magnesium ions is the result of electrostatic interactions of these ions with the charges on the external surface of membranes. A possible role of regulation of the electron transport rate by magnesium ions in vivo is discussed.

  11. Role of Glycosyltransferases Modifying Type B Flagellin of Emerging Hypervirulent Clostridium difficile Lineages and Their Impact on Motility and Biofilm Formation*

    Science.gov (United States)

    Valiente, Esmeralda; Bouché, Laura; Hitchen, Paul; Faulds-Pain, Alexandra; Songane, Mario; Dawson, Lisa F.; Donahue, Elizabeth; Stabler, Richard A.; Panico, Maria; Morris, Howard R.; Bajaj-Elliott, Mona; Logan, Susan M.; Dell, Anne; Wren, Brendan W.

    2016-01-01

    Clostridium difficile is the principal cause of nosocomial infectious diarrhea worldwide. The pathogen modifies its flagellin with either a type A or type B O-linked glycosylation system, which has a contributory role in pathogenesis. We study the functional role of glycosyltransferases modifying type B flagellin in the 023 and 027 hypervirulent C. difficile lineages by mutagenesis of five putative glycosyltransferases and biosynthetic genes. We reveal their roles in the biosynthesis of the flagellin glycan chain and demonstrate that flagellar post-translational modification affects motility and adhesion-related bacterial properties of these strains. We show that the glycosyltransferases 1 and 2 (GT1 and GT2) are responsible for the sequential addition of a GlcNAc and two rhamnoses, respectively, and that GT3 is associated with the incorporation of a novel sulfonated peptidyl-amido sugar moiety whose structure is reported in our accompanying paper (Bouché, L., Panico, M., Hitchen, P., Binet, D., Sastre, F., Faulds-Pain, A., Valiente, E., Vinogradov, E., Aubry, A., Fulton, K., Twine, S., Logan, S. M., Wren, B. W., Dell, A., and Morris, H. R. (2016) J. Biol. Chem. 291, 25439–25449). GT2 is also responsible for methylation of the rhamnoses. Whereas type B modification is not required for flagellar assembly, some mutations that result in truncation or abolition of the glycan reduce bacterial motility and promote autoaggregation and biofilm formation. The complete lack of flagellin modification also significantly reduces adhesion of C. difficile to Caco-2 intestinal epithelial cells but does not affect activation of human TLR5. Our study advances our understanding of the genes involved in flagellar glycosylation and their biological roles in emerging hypervirulent C. difficile strains. PMID:27703012

  12. PsbS-specific zeaxanthin-independent changes in fluorescence emission spectrum as a signature of energy-dependent non-photochemical quenching in higher plants.

    Science.gov (United States)

    Zulfugarov, Ismayil S; Tovuu, Altanzaya; Dogsom, Bolormaa; Lee, Chung Yeol; Lee, Choon-Hwan

    2010-05-01

    The PsbS protein of photosystem II is necessary for the development of energy-dependent quenching of chlorophyll (Chl) fluorescence (qE), and PsbS-deficient Arabidopsis plant leaves failed to show qE-specific changes in the steady-state 77 K fluorescence emission spectra observed in wild-type leaves. The difference spectrum between the quenched and un-quenched states showed a negative peak at 682 nm. Although the level of qE development in the zeaxanthin-less npq1-2 mutant plants, which lacked violaxanthin de-epoxidase enzyme, was only half that of wild type, there were no noticeable changes in this qE-dependent difference spectrum. This zeaxanthin-independent DeltaF682 signal was not dependent on state transition, and the signal was not due to photobleaching of pigments either. These results suggest that DeltaF682 signal is formed due to PsbS-specific conformational changes in the quenching site of qE and is a new signature of qE generation in higher plants.

  13. UV Screening in Native and Non-native Plant Species in the Tropical Alpine: Implications for Climate Change-Driven Migration of Species to Higher Elevations

    Directory of Open Access Journals (Sweden)

    Paul W. Barnes

    2017-08-01

    Full Text Available Ongoing changes in Earth’s climate are shifting the elevation ranges of many plant species with non-native species often experiencing greater expansion into higher elevations than native species. These climate change-induced shifts in distributions inevitably expose plants to novel biotic and abiotic environments, including altered solar ultraviolet (UV-B (280–315 nm radiation regimes. Do the greater migration potentials of non-native species into higher elevations imply that they have more effective UV-protective mechanisms than native species? In this study, we surveyed leaf epidermal UV-A transmittance (TUV A in a diversity of plant species representing different growth forms to test whether native and non-native species growing above 2800 m elevation on Mauna Kea, Hawaii differed in their UV screening capabilities. We further compared the degree to which TUV A varied along an elevation gradient in the native shrub Vaccinium reticulatum and the introduced forb Verbascum thapsus to evaluate whether these species differed in their abilities to adjust their levels of UV screening in response to elevation changes in UV-B. For plants growing in the Mauna Kea alpine/upper subalpine, we found that adaxial TUV A, measured with a UVA-PAM fluorometer, varied significantly among species but did not differ between native (mean = 6.0%; n = 8 and non-native (mean = 5.8%; n = 11 species. When data were pooled across native and non-native taxa, we also found no significant effect of growth form on TUV A, though woody plants (shrubs and trees were represented solely by native species whereas herbaceous growth forms (grasses and forbs were dominated by non-native species. Along an elevation gradient spanning 2600–3800 m, TUV A was variable (mean range = 6.0–11.2% and strongly correlated with elevation and relative biologically effective UV-B in the exotic V. thapsus; however, TUV A was consistently low (3% and did not vary with elevation in the native

  14. Site-saturation engineering of lysine 47 in cyclodextrin glycosyltransferase from Paenibacillus macerans to enhance substrate specificity towards maltodextrin for enzymatic synthesis of 2-O-D-glucopyranosyl-L-ascorbic acid (AA-2G).

    Science.gov (United States)

    Han, Ruizhi; Liu, Long; Shin, Hyun-dong; Chen, Rachel R; Du, Guocheng; Chen, Jian

    2013-07-01

    In this work, the site-saturation engineering of lysine 47 in cyclodextrin glycosyltransferase (CGTase) from Paenibacillus macerans was conducted to improve the specificity of CGTase towards maltodextrin, which can be used as a cheap and easily soluble glycosyl donor for the enzymatic synthesis of 2-O-D-glucopyranosyl-L-ascorbic acid (AA-2G) by CGTase. When using maltodextrin as glycosyl donor, four mutants K47F (lysine→ phenylalanine), K47L (lysine→ leucine), K47V (lysine→ valine) and K47W (lysine→ tryptophan) showed higher AA-2G yield as compared with that produced by the wild-type CGTase. The transformation conditions (temperature, pH and the mass ratio of L-ascorbic acid to maltodextrin) were optimized and the highest titer of AA-2G produced by the mutant K47L could reach 1.97 g/l, which was 64.2% higher than that (1.20 g/l) produced by the wild-type CGTase. The reaction kinetics analysis confirmed the enhanced maltodextrin specificity, and it was also found that compared with the wild-type CGTase, the four mutants had relatively lower cyclization activities and higher disproportionation activities, which was favorable for AA-2G synthesis. The mechanism responsible for the enhanced substrate specificity was further explored by structure modeling and it was indicated that the enhancement of maltodextrin specificity may be due to the short residue chain and the removal of hydrogen bonding interactions between the side chain of residue 47 and the sugar at -3 subsite. Here the obtained mutant CGTases, especially the K47L, has a great potential in the production of AA-2G with maltodextrin as a cheap and easily soluble substrate.

  15. Use resources of human exometabolites of different oxidation levels for higher plants cultivation on the soil-like substrate as applied to closed ecosystems

    Science.gov (United States)

    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

  16. Tritium behaviour in higher plants

    International Nuclear Information System (INIS)

    Guenot, J.

    1984-05-01

    Vine grapes and potato seedlings have been exposed in situ to tritiated water vapor and 14 C labeled carbon dioxide. Leaves sampling was done during and after the exposition. Measurements allowed to distinguish the three forms of tritium in leaves, i.e. tissue free water tritium (TFWT) and organically bound tritium (OBT), in exchangeable position or not. The results lead to a description of the dynamical behaviour of tritium between these three compartments. It has been shown that 20% of organically bound hydrogen is readily exchangeable thus being in permanent isotopic equilibium with tissue free water. Moreover, the activity of nonexchangeable OBT appears to be strongly related to the organic 14 C, which shows that photosynthesis is responsible of tritium incorporation in organic nonexchangeable position, and occurs with a 20% discrimination in favor of protium. In contrast with the other two compartments, this fixation is almost irreversible, which is a fact of importance from a radiological point of view [fr

  17. Development of uniformly stable isotope labeling system in higher plants for hetero-nuclear NMR experiments in vitro and in vivo

    International Nuclear Information System (INIS)

    Kikuchi, J.

    2005-01-01

    Full text: Novel methods for measurement of living systems are making new breakthroughs in life science. In the era of the metabolome (analysis of all measurable metabolites), a MS-based approach is considered to be the major technology, whereas a NMR-based method is recognized as minor technology due to its low sensitivity. Therefore, my laboratory is currently focusing to develop novel methodologies for an NMR-based metabolomics. This will be achieved by uniform stable isotope labeling of higher plants allowing application of multi-dimensional NMR experiments used in protein structure determination. Using these novel methods, I will analyze the dynamic molecular networks inside tissues. Especially, use of stable isotope labeling methods has enormous advantage for discrimination of incorporated or de novo synthesized compounds. Furthermore, potentiality of in vivo-NMR metabolomics will be discussed in the conference. (author)

  18. Effects of combined action of γ-irradiation and sulfur dioxide or N-methyl-N'-nitro-N-nitrosoguanidin on bacteria and higher plants

    International Nuclear Information System (INIS)

    Kal'chenko, V.A.; Lotareva, O.V.; Spirin, D.A.; Karaban', R.T.; Mal'tseva, L.N.; Ignat'ev, A.A.

    1988-01-01

    Effect of combined action of of gamma-irradiation and sulfur dioxide or N-methyl-N-nitro-N-nitrosoguanidin on baceria (Bacillus subtilis) and higher plants (Hordeum vulgare L., Pinus sylvestris L.) have been studied. The number of barley germ root cells with chromosomal aberrations depends on the order of treatment with the studied agents. The coefficients of SO 2 and gamma-irradiation correlation fluctuate from 1,3 to 2,6 in the above experiments. In experiments with pine seedlings, these correlation coefficients were similar to additive ones. The data obtained suggest that the pattern of action of the agents is determined by the radiation sensitivity of objects and the order of action of the agents

  19. Biochemical studies on the effect of fluoride on higher plants. I. Metabolism of carbohydrates, organic acids and amino acids. [Glycine max var. Hawkeye

    Energy Technology Data Exchange (ETDEWEB)

    Yang, S F; Miller, G W

    1963-01-01

    Metabolic processes associated with free sugars, organic acids and amino acids in higher plants subjected to fluoride fumigation were studied quantitatively. Fluoride-fumigated leaves contained more reducing sugars and less sucrose than the normal leaves. This result suggested inhibition of sucrose synthesis by fluoride. Necrotic leaves contained increased total concentrations of organic acids, which were mostly attributable to malic acid, malonic acid and citric acid. The greater increase in malic acid relative to that of citric acid was the reverse of results observed in chlorotic tissue. Necrotic leaves contained enhanced amounts of free amino acids. The greatest increase occurred in the concentration of asparagine and might be related to the increased respiratory rate of necrotic leaves. Pipecolic acid accumulated in large quantities in nicrotic tissue and was not detected in normal leaves. The accumulation of organic acids and amino acids in leaves during fluoride fumigation was evidenced by a lowered respiratory quotient.

  20. Chromosomal mutation by fission neutrons and X-rays in higher plants. A review on results of the joint research program utilizing Kinki University reactor

    International Nuclear Information System (INIS)

    Yonezawa, Yoshihiko

    2010-01-01

    We have studied the efficiency of fission neutrons from the nuclear reactor of Kinki University (UTR-KINKI) and X-rays to chromosomes of higher plants for over 20 years. In this review, we described the development of bio-dosimeter using hyper-sensibility of germinating onion roots for irradiation, the analysis of chromosome structure in Haplopappus gracilis (Asteraceae), with the special reference of latent centromeres and survived telomeres throughout chromosomal evolution, the experimental studies on the induction of chromosomal rearrangement in Zebrina pendula (Commelinaceae), the behavior of chromosome fragments with non-localized centromeres in Carex and Eleocharis (Cyperaceae), and the possibility as a bio-dosimeter of pollen mother cells of Tradescantia paludosa (Commelinaceae) for the detection of low-dose radiation. (author)

  1. Isolation of alkalophilic CGTase-producing bacteria and characterization of cyclodextrin-glycosyltransferase

    Directory of Open Access Journals (Sweden)

    lma Hiroko Higuti

    2003-03-01

    Full Text Available One hundred and twenty five soil samples were collected from the regions of roots of corn, cassava, potato, bean, sugar cane, soya, and pumpkin. From these, 75 strains were isolated that produced a yellowish halo surrounding the colonies, due to a phenolphtalein-cyclodextrin (CD complex, and these were selected as alkalophilic CGTase-producing bacteria. All the 75 strains were identified as Bacillus firmus by microscopy and biochemical tests. The activity of the CGTase's varied from 2² to 2(10 dilutions,when assayed by CD-trichloroethylene (TCE-complex precipitation. Strain 31 that produced the enzyme at the higher level was selected, and its enzyme was partially purified by starch adsorption (x 17 in a yield of 51%. Maximum enzyme activity occurred at pH 5.5 and 8.5. At pH 5.5, the optimum temperature was 60°C. On increased from 30°C to 85°C, the thermodynamic parameter for activation energy was 8.27 kcal.mol-1. The enzyme was inhibited by Ca2+, Mg2+, Fe2+, Cu2+, Mn2+, and Zn2+.Foram coletadas 125 amostras de solo de raízes de milho, mandioca, batata, feijão, cana-de-açúcar, soja e abóbora. Destas, 75 cepas foram isoladas por desenvolverem um halo amarelo ao redor das colônias, devido a formação do complexo fenoftaleína-ciclodextrina (CD sendo selecionadas como bactérias alcalofílicas produtoras de CGTase (EC 2.4.1.19.Todas as 75 cepas foram identificadas como Bacillus firmus por microscopia e testes bioquímicos. Quando ensaiada por precipitação com tricloroetileno a atividade da CGTase variou de diluição de 2² a 2(10. A cepa 31 foi selecionada devido a elevada produção de enzima, sendo esta parcialmente purificada por adsorção em amido (17 vezes com uma recuperação de 51%. A máxima atividade enzimática ocorreu em pH 5,5 e 8,5. Em pH 5,5, a temperatura ótima foi de 60° C. Sob o aumento de 30° C a 85° C, o parâmetro de energia de ativação foi de 8,27 kcal.mol-1. A enzima foi inibida por Ca2+, Mg2+, Fe2+, Cu2

  2. Are lower epiphytes really that better than higher plants for indicating airborne contaminants? An insight into the elemental contents of lichen thalli and tree bark by INAA

    International Nuclear Information System (INIS)

    Pacheco, A.M.G.; Freitas, M.C.

    2004-01-01

    Few dedicated attempts at comparing the monitoring performance of lower and higher plants have been carried out so far. As a contribution to such an issue, the relative magnitude of elemental signals from epiphytic lichens (Parmelia spp.) and olive tree (Olea europaea Linn.) bark, determined by INAA is studied. A representative set of 12 elements - As, Ba, Br, Ca, Cl, K, Mg, Mn, Na, Sr, V, Zn - was used for an ab initio comparison between raw data and Rb-normalized data, using distribution-free statistics. Correlation analysis shows an overall improvement in the degree of association between bark and lichen signals when proceeding from raw data to relative enrichment. Apart from Cl, no element is enriched in lichens to a higher extent than in bark. Sign tests are quite conclusive: bark factors are either statistically greater than or equal to lichens'. These findings prompt a word of caution when dealing with biological monitoring data, without accounting for soil, rock or litter inputs into the biomonitors' elemental pools. (author)

  3. Shifted Golgi targeting of glycosyltransferases and α-mannosidase IA from giantin to GM130-GRASP65 results in formation of high mannose N-glycans in aggressive prostate cancer cells.

    Science.gov (United States)

    Bhat, Ganapati; Hothpet, Vishwanath-Reddy; Lin, Ming-Fong; Cheng, Pi-Wan

    2017-11-01

    There is a pressing need for biomarkers that can distinguish indolent from aggressive prostate cancer to prevent over-treatment of patients with indolent tumor. Golgi targeting of glycosyltransferases was characterized by confocal microscopy after knockdown of GM130, giantin, or both. N-glycans on a trans-Golgi enzyme β4galactosyltransferase-1 isolated by immunoprecipitation from androgen-sensitive and independent prostate cancer cells were determined by matrix-assisted laser desorption-time of flight-mass spectrometry. In situ proximity ligation assay was employed to determine co-localization of (a) α-mannosidase IA, an enzyme required for processing Man 8 GlcNAc 2 down to Man 5 GlcNAc 2 to enable synthesis of complex-type N-glycans, with giantin, GM130, and GRASP65, and (b) trans-Golgi glycosyltransferases with high mannose N-glycans terminated with α3-mannose. Defective giantin in androgen-independent prostate cancer cells results in a shift of Golgi targeting of glycosyltransferases and α-mannosidase IA from giantin to GM130-GRASP65. Consequently, trans-Golgi enzymes and cell surface glycoproteins acquire high mannose N-glycans, which are absent in cells with functional giantin. In situ proximity ligation assays of co-localization of α-mannosidase IA with GM130 and GRASP65, and trans-Golgi glycosyltransferases with high mannose N-glycans are negative in androgen-sensitive LNCaP C-33 cells but positive in androgen-independent LNCaP C-81 and DU145 cells, and LNCaP C-33 cells devoid of giantin. In situ proximity ligation assays of Golgi localization of α-mannosidase IA at giantin versus GM130-GRASP65 site, and absence or presence of N-glycans terminated with α3-mannose on trans-Golgi glycosyltransferases may be useful for distinguishing indolent from aggressive prostate cancer cells. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Representation of pheromones, interspecific signals, and plant odors in higher olfactory centers; mapping physiologically identified antennal-lobe projection neurons in the male heliothine moth

    Directory of Open Access Journals (Sweden)

    Xin-Cheng eZhao

    2014-10-01

    Full Text Available In the primary olfactory centre 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 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 odours 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 reproductive isolation 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, 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 labelled 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 odours, pheromones, and interspecific signals in the higher brain regions of each species, we have created standard brain atlases and registered three-dimensional models of distinct uniglomerular projection neuron types into the relevant atlas.

  5. Vaccination of Elk (Cervus canadensis) with Brucella abortus Strain RB51 Overexpressing Superoxide Dismutase and Glycosyltransferase Genes Does Not Induce Adequate Protection against Experimental Brucella abortus Challenge.

    Science.gov (United States)

    Nol, Pauline; Olsen, Steven C; Rhyan, Jack C; Sriranganathan, Nammalwar; McCollum, Matthew P; Hennager, Steven G; Pavuk, Alana A; Sprino, Phillip J; Boyle, Stephen M; Berrier, Randall J; Salman, Mo D

    2016-01-01

    In recent years, elk (Cervus canadensis) have been implicated as the source of Brucella abortus infection for numerous cattle herds in the Greater Yellowstone Area. In the face of environmental and ecological changes on the landscape, the range of infected elk is expanding. Consequently, the development of effective disease management strategies for wild elk herds is of utmost importance, not only for the prevention of reintroduction of brucellosis to cattle, but also for the overall health of the Greater Yellowstone Area elk populations. In two studies, we evaluated the efficacy of B. abortus strain RB51 over-expressing superoxide dismutase and glycosyltransferase for protecting elk from infection and disease caused by B. abortus after experimental infection with a virulent B. abortus strain. Our data indicate that the recombinant vaccine does not protect elk against brucellosis. Further, work is needed for development of an effective brucellosis vaccine for use in elk.

  6. Enzymatic Synthesis of Acylphloroglucinol 3-C-Glucosides from 2-O-Glucosides using a C-Glycosyltransferase from Mangifera indica.

    Science.gov (United States)

    Chen, Dawei; Sun, Lili; Chen, Ridao; Xie, Kebo; Yang, Lin; Dai, Jungui

    2016-04-18

    A green and cost-effective process for the convenient synthesis of acylphloroglucinol 3-C-glucosides from 2-O-glucosides was exploited using a novel C-glycosyltransferase (MiCGTb) from Mangifera indica. Compared with previously characterized CGTs, MiCGTb exhibited unique de-O-glucosylation promiscuity and high regioselectivity toward structurally diverse 2-O-glucosides of acylphloroglucinol and achieved high yields of C-glucosides even with a catalytic amount of uridine 5'-diphosphate (UDP). These findings demonstrate for the first time the significant potential of a single-enzyme approach to the synthesis of bioactive C-glucosides from both natural and unnatural acylphloroglucinol 2-O-glucosides. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Potential physiological role of plant glycosidase inhibitors

    DEFF Research Database (Denmark)

    Bellincampi, D.; Carmadella, L.; Delcour, J.A.

    2004-01-01

    Carbohydrate-active enzymes including glycosidases, transglycosidases, glycosyltransferases, polysaccharide lyases and carbohydrate esterases are responsible for the enzymatic processing of carbohydrates in plants. A number of carbohydrate-active enzymes are produced by microbial pathogens...... and insects responsible of severe crop losses. Plants have evolved proteinaceous inhibitors to modulate the activity of several of these enzymes. The continuing discovery of new inhibitors indicates that this research area is still unexplored and may lead to new exciting developments. To date, the role...... of the inhibitors is not completely understood. Here we review recent results obtained on the best characterised inhibitors, pointing to their possible biological role in vivo. Results recently obtained with plant transformation technology indicate that this class of inhibitors has potential biotechnological...

  8. Effect of plants in constructed wetlands for organic carbon and nutrient removal: a review of experimental factors contributing to higher impact and suggestions for future guidelines.

    Science.gov (United States)

    Jesus, João M; Danko, Anthony S; Fiúza, António; Borges, Maria-Teresa

    2018-02-01

    Constructed wetland is a proven technology for water pollution removal, but process mechanisms and their respective contribution are not fully understood. The present review details the effect of plants on removal efficiency of constructed wetlands by focusing on literature that includes experiments with unplanted controls for organic carbon and nutrient (N and P) removal. The contribution of plant direct uptake is also assessed. Although it was found that several studies, mostly at laboratory or pilot scales, showed no statistical differences between planted and unplanted controls, some factors were found that help maximize the effect of plants. This study intends to contribute to a better understanding of the significance of the effect of plants in a constructed wetland, as well as to suggest a set of experimental guidelines in this field.

  9. Rare ginsenoside Ia synthesized from F1 by cloning and overexpression of the UDP-glycosyltransferase gene from Bacillus subtilis: synthesis, characterization, and in vitro melanogenesis inhibition activity in BL6B16 cells.

    Science.gov (United States)

    Wang, Dan-Dan; Jin, Yan; Wang, Chao; Kim, Yeon-Ju; Perez, Zuly Elizabeth Jimenez; Baek, Nam In; Mathiyalagan, Ramya; Markus, Josua; Yang, Deok-Chun

    2018-01-01

    Ginsenoside F1 has been described to possess skin-whitening effects on humans. We aimed to synthesize a new ginsenoside derivative from F1 and investigate its cytotoxicity and melanogenesis inhibitory activity in B16BL6 cells using recombinant glycosyltransferase enzyme. Glycosylation has the advantage of synthesizing rare chemical compounds from common compounds with great ease. UDP-glycosyltransferase (BSGT1) gene from Bacillus subtilis was selected for cloning. The recombinant glycosyltransferase enzyme was purified, characterized, and utilized to enzymatically transform F1 into its derivative. The new product was characterized by NMR techniques and evaluated by MTT, melanin count, and tyrosinase inhibition assay. The new derivative was identified as (20 S )-3 β ,6 α ,12 β ,20-tetrahydroxydammar-24-ene-20- O - β -D-glucopyranosyl-3- O - β -D-glucopyranoside (ginsenoside Ia), which possesses an additional glucose linked into the C-3 position of substrate F1. Ia had been previously reported; however, no in vitro biological activity was further examined. This study focused on the mass production of arduous ginsenoside Ia from accessible F1 and its inhibitory effect of melanogenesis in B16BL6 cells. Ia showed greater inhibition of melanin and tyrosinase at 100 μmol/L than F1 and arbutin. These results suggested that Ia decreased cellular melanin synthesis in B16BL6 cells through downregulation of tyrosinase activity. To our knowledge, this is the first study to report on the mass production of rare ginsenoside Ia from F1 using recombinant UDP-glycosyltransferase isolated from B. subtillis and its superior melanogenesis inhibitory activity in B16BL6 cells as compared to its precursor. In brief, ginsenoside Ia can be applied for further study in cosmetics.

  10. Use of human wastes oxidized to different degrees in cultivation of higher plants on the soil-like substrate intended for closed ecosystems

    Science.gov (United States)

    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

  11. Characterization of cysteine-degrading and H2S-releasing enzymes of higher plants - from the field to the test tube and back.

    Science.gov (United States)

    Papenbrock, J; Riemenschneider, A; Kamp, A; Schulz-Vogt, H N; Schmidt, A

    2007-09-01

    Due to the clean air acts and subsequent reduction of emission of gaseous sulfur compounds sulfur deficiency became one of the major nutrient disorders in Northern Europe. Typical sulfur deficiency symptoms can be diagnosed. Especially plants of the Cruciferae family are more susceptible against pathogen attack. Sulfur fertilization can in part recover or even increase resistance against pathogens in comparison to sulfur-deficient plants. The term sulfur-induced resistance (SIR) was introduced, however, the molecular basis for SIR is largely unknown. There are several sulfur-containing compounds in plants which might be involved in SIR, such as high levels of thiols, glucosinolates, cysteine-rich proteins, phytoalexins, elemental sulfur, or H2S. Probably more than one strategy is used by plants. Species- or even variety-dependent differences in the development of SIR are probably used. Our research focussed mainly on the release of H2S as defence strategy. In field experiments using different BRASSICA NAPUS genotypes it was shown that the genetic differences among BRASSICA genotypes lead to differences in sulfur content and L-cysteine desulfhydrase activity. Another field experiment demonstrated that sulfur supply and infection with PYRENOPEZIZA BRASSICA influenced L-cysteine desulfhydrase activity in BRASSICA NAPUS. Cysteine-degrading enzymes such as cysteine desulfhydrases are hypothesized to be involved in H2S release. Several L- and D-cysteine-specific desulfhydrase candidates have been isolated and partially analyzed from the model plant ARABIDOPSIS THALIANA. However, it cannot be excluded that H2S is also released in a partial back reaction of O-acetyl-L-serine(thiol)lyase or enzymes not yet characterized. For the exact determination of the H2S concentration in the cell a H2S-specific microsensor was used the first time for plant cells. The transfer of the results obtained for application back on BRASSICA was initiated.

  12. Materials for higher steam temperatures (up to 600 deg C) in biomass and waste fired plant. A review of present knowledge; Material foer hoegre aangtemperaturer (upp till 600 grader C) i bio- och avfallseldade anlaeggningar

    Energy Technology Data Exchange (ETDEWEB)

    Staalenheim, Annika; Henderson, Pamela

    2011-02-15

    A goal for the Swedish power industry is to build a demonstration biomass-fired plant with 600 deg C steam data in 2015. Vaermeforsk also has a goal to identify materials that can be used in such a plant. This project involves a survey of present knowledge and published articles concerning materials that are suitable for use in biomass and wastefired plants with steam data up to 600 deg C. The information has been gathered from plants presently in operation, and from field tests previously performed with probes. Plants firing only household waste are excluded. The components considered are waterwalls/furnace walls (affected because of higher steam pressures) and superheaters. Fireside corrosion and steam-side oxidation are dealt with. Candidate materials (or coatings) are suggested and areas for further research have been identified. The purpose of this project is to give state-of-the-art information on what materials could be used in biomass and waste-fired plant to reach a maximum steam temperature of 600 deg C. This report is aimed at suppliers of boilers and materials, energy utility companies and others involved in building new plant with higher steam data. In accordance with the goals of this project: - Materials suitable for use at higher steam temperatures (up to 600 deg C steam) in wood-based biomass and waste-fired plant have been identified. Austenitic stainless steels HR3C, TP 347 HFG and AC66 all have adequate strength, steam-side oxidation and fireside corrosion resistance for use as superheaters. AC66 and HR3C have better steam-side oxidation resistance than TP 347 HFG , but TP 347 HFG has better fireside corrosion resistance. It is recommended that TP 347 HFG be shot-peened on the inside to improve the oxidation resistance if in service with steam temperatures above 580 deg C. - Furnace walls coated with Ni-based alloys or a mixture of Ni- alloy and ceramic show good corrosion resistance at lower temperatures and should be evaluated at higher

  13. Suppression of the invasive plant mile-a-minute (Mikania micrantha) by local crop sweet potato (Ipomoea batatas) by means of higher growth rate and competition for soil nutrients.

    Science.gov (United States)

    Shen, Shicai; Xu, Gaofeng; Clements, David Roy; Jin, Guimei; Chen, Aidong; Zhang, Fudou; Kato-Noguchi, Hisashi

    2015-01-28

    There are a variety of ways of increasing crop diversity to increase agricultural sustainability and in turn having a positive influence on nearby natural ecosystems. Competitive crops may provide potent management tools against invasive plants. To elucidate the competitive mechanisms between a sweet potato crop (Ipomoea batatas) and an invasive plant, mile-a-minute (Mikania micrantha), field experiments were carried out in Longchuan County of Yunnan Province, Southwest China, utilizing a de Wit replacement series. The trial incorporated seven ratios of sweet potato and mile-a-minute plants in 25 m(2) plots. In monoculture, the total biomass, biomass of adventitious root, leafstalk length, and leaf area of sweet potato were all higher than those of mile-a-minute, and in mixed culture the plant height, branch, leaf, stem node, adventitious root, flowering and biomass of mile-a-minute were suppressed significantly (P competition was less than interspecific competition. The competitive balance index of sweet potato demonstrated a higher competitive ability than mile-a-minute. Except pH, other soil nutrient contents of initial soil (CK) were significantly higher than those of seven treatments. The concentrations of soil organic matter, total N, total K, available N, available P, available K, exchange Ca, exchange Mg, available Mn, and available B were significantly greater (P competition of sweet potato in the mixture. Evidently sweet potato has a competitive advantage in terms of plant growth characteristics and greater absorption of soil nutrients. Thus, planting sweet potato is a promising technique for reducing infestations of mile-a-minute, providing weed management benefits and economic returns from harvest of sweet potatoes. This study also shows the potential value of replacement control methods which may apply to other crop-weed systems or invaded natural ecosystems.

  14. Expression and Purification of Glycosyltransferases in Pichia Pastoris: Towards Improving the Migration of Stem Cells by Enhancing Surface Expression of Sialyl Lewis X

    KAUST Repository

    Al-Amoodi, Asma S.

    2017-05-01

    Recruitment of circulating cells towards target sites is primarily dependent on E-selectin receptor/ligand adhesive interactions. Glycosyltransferase (GTs) are involved in the creation of E-selectin ligands. A sialofucosylated terminal tetrasaccharide like glycan structure known as sialyl Lewis x (sLex), is the most recognized ligand by selectins. This structure is found on the surface of cancer cells and leukocytes but is often absent on the surface of many adult stem cell populations. In order to synthesize sLex, GTs must be endogenously expressed and remain active within the cells. Generally, these stem cells express terminal sialylated lactosamine structures on their glycoproteins which require the addition of alpha-(1,3)-fucose to be converted into an E-selectin ligand. There are a number of fucosyltransferases (FUTs) that are able to modify terminal lactosamine structures to create sLex such as FUT6. In this work we focused on expressing and purifying active recombinant FUTs as a tool to help create sLex structures on the surface of adult stem cells in order to enhance their migration.

  15. Over-expression of UDP-glycosyltransferase gene UGT2B17 is involved in chlorantraniliprole resistance in Plutella xylostella (L.).

    Science.gov (United States)

    Li, Xiuxia; Zhu, Bin; Gao, Xiwu; Liang, Pei

    2017-07-01

    UDP-glycosyltransferases (UGTs) are phase II detoxification enzymes widely distributed within living organisms. Their involvement in the biotransformation of various lipophilic endogenous compounds and phytoalexins in insects has been documented. However, the roles of this enzyme family in insecticide resistance have rarely been reported. Here, the functions of UGTs in chlorantraniliprole resistance in Plutella xylostella were investigated. Treatment with sulfinpyrazone and 5-nitrouracil (both inhibitors of UGT enzymes) significantly increased the toxicity of chlorantraniliprole against the third instar larvae of P. xylostella. Among the 23 UGT transcripts examined, only UGT2B17 was found to be over-expressed (with a range from 30.7- to 77.3-fold) in all four chlorantraniliprole-resistant populations compared to the susceptible one (CHS). The knock-down of UGT2B17 by RNA interference (RNAi) dramatically increased the toxicity of chlorantraniliprole by 27.4% and 29.8% in the CHS and CHR (resistant) populations, respectively. In contrast, exposure to phenobarbital significantly increased the relative expression of UGT2B17 while decreasing the toxicity of chlorantraniliprole to the larvae by 14.0%. UGT2B17 is involved in the detoxification of chlorantraniliprole, and its over-expression may play an important role in chlorantraniliprole resistance in P. xylostella. These results shed some light upon and further our understanding of the mechanisms of diamide insecticide resistance in insects. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  16. A DUF-246 family glycosyltransferase-like gene affects male fertility and the biosynthesis of pectic arabinogalactans

    DEFF Research Database (Denmark)

    Stonebloom, Solomon; Ebert, Berit; Xiong, Guangyan

    2016-01-01

    rates of pollen tube formation in pollen from pagr heterozygotes. To characterize a loss-of-function phenotype for PAGR, the Nicotiana benthamiana orthologs, NbPAGR-A and B, were transiently silenced using Virus Induced Gene Silencing. NbPAGR-silenced plants exhibited reduced internode and petiole...

  17. Characterization of cysteine-degrading and H2S-releasing enzymes of higher plants - From the field to the test tube and back

    DEFF Research Database (Denmark)

    Jutta, Papenbrock; Anja, Riemenschneider; Kamp, Anja

    2007-01-01

    focussed mainly on the release of H2S as defence strategy. In field experiments using different Brassica napus genotypes it was shown that the genetic differ- ences among Brassica genotypes lead to differences in sulfur content and L-cysteine desulfhydrase activity. Another field ex- periment demonstrated...... that sulfur supply and infection with Pyrenopeziza brassica influenced L-cysteine desulfhydrase activity in Brassica napus. Cysteine-degrading enzymes such as cysteine desulfhydrases are hypothesized to be involved in H2S release. Several L- and D-cysteine-specific desulfhydrase candidates have been isolated...... in plants which might be involved in SIR, such as high levels of thiols, glucosinolates, cysteine-rich proteins, phytoalexins, elemental sulfur, or H2S. Probably more than one strategy is used by plants. Species- or even variety-dependent differences in the development of SIR are probably used. Our research...

  18. Higher Education

    African Journals Online (AJOL)

    Kunle Amuwo: Higher Education Transformation: A Paradigm Shilt in South Africa? ... ty of such skills, especially at the middle management levels within the higher ... istics and virtues of differentiation and diversity. .... may be forced to close shop for lack of capacity to attract ..... necessarily lead to racial and gender equity,.

  19. A membrane-anchored E-type endo-1,4-beta-glucanase is localized on Golgi and plasma membranes of higher plants.

    Science.gov (United States)

    Brummell, D A; Catala, C; Lashbrook, C C; Bennett, A B

    1997-04-29

    Endo-1,4-beta-D-glucanases (EGases, EC 3.2.1.4) are enzymes produced in bacteria, fungi, and plants that hydrolyze polysaccharides possessing a 1,4-beta-D-glucan backbone. All previously identified plant EGases are E-type endoglucanases that possess signal sequences for endoplasmic reticulum entry and are secreted to the cell wall. Here we report the characterization of a novel E-type plant EGase (tomato Cel3) with a hydrophobic transmembrane domain and structure typical of type II integral membrane proteins. The predicted protein is composed of 617 amino acids and possesses seven potential sites for N-glycosylation. Cel3 mRNA accumulates in young vegetative tissues with highest abundance during periods of rapid cell expansion, but is not hormonally regulated. Antibodies raised to a recombinant Cel3 protein specifically recognized three proteins, with apparent molecular masses of 93, 88, and 53 kDa, in tomato root microsomal membranes separated by sucrose density centrifugation. The 53-kDa protein comigrated in the gradient with plasma membrane markers, the 88-kDa protein with Golgi membrane markers, and the 93-kDa protein with markers for both Golgi and plasma membranes. EGase enzyme activity was also found in regions of the density gradient corresponding to both Golgi and plasma membranes, suggesting that Cel3 EGase resides in both membrane systems, the sites of cell wall polymer biosynthesis. The in vivo function of Cel3 is not known, but the only other known membrane-anchored EGase is present in Agrobacterium tumefaciens where it is required for cellulose biosynthesis.

  20. Adenosine 3':5'-cyclic monophosphate in higher plants: Isolation and characterization of adenosine 3':5'-cyclic monophosphate from Kalanchoe and Agave.

    Science.gov (United States)

    Ashton, A R; Polya, G M

    1977-01-01

    1.3':5'-Cyclic AMP was extensively purified from Kalanchoe daigremontiana and Agave americana by neutral alumina and anion- and cation-exchange column chromatography. Inclusion of 3':5'-cyclic [8-3H]AMP from the point of tissue extraction permitted calculation of yields. The purification procedure removed contaminating material that was shown to interfere with the 3':5'-cyclic AMP estimation and characterization procedures. 2. The partially purified 3':5'-cyclic AMP was quantified by means of a radiochemical saturation assay using an ox heart 3':5'-cyclic AMP-binding protein and by an assay involving activation of a mammalian protein kinase. 3. The plant 3':5'-cyclic AMP co-migrated with 3':5'-cyclic [8-3H]AMP on cellulose chromatography, poly(ethyleneimine)-cellulose chromatography and silica-gel t.l.c. developed with several solvent systems. 4. The plant 3':5'-cyclic AMP was degraded by ox heart 3':5'-cyclic nucleotide phosphodiesterase at the same rates as authentic 3':5'-cyclic AMP. 1-Methyl-3-isobutylxanthine (1 mM), a specific inhibitor of the 3':5'-cyclic nucleotide phosphodieterase, completely inhibited such degradation. 5. The concentrations of 3':5'-cyclic AMP satisfying the above criteria in Kalanchoe and Agave were 2-6 and 1 pmol/g fresh wt. respectively. Possible bacterial contribution to these analyses was estimated to be less than 0.002pmol/g fresh wt. Evidence for the occurrence of 3':5'-cyclic AMP in plants is discussed. PMID:196595

  1. Engineering stategies and implications of using higher plants for throttling gas and water exchange in a controlled ecological life support system

    Science.gov (United States)

    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.

  2. Bug22p, a Conserved Centrosomal/Ciliary Protein Also Present in Higher Plants, Is Required for an Effective Ciliary Stroke in Paramecium ▿ †

    Science.gov (United States)

    Laligné, C.; Klotz, C.; Garreau de Loubresse, N.; Lemullois, M.; Hori, M.; Laurent, F. X.; Papon, J. F.; Louis, B.; Cohen, J.; Koll, F.

    2010-01-01

    Centrioles, cilia, and flagella are ancestral conserved organelles of eukaryotic cells. Among the proteins identified in the proteomics of ciliary proteins in Paramecium, we focus here on a protein, Bug22p, previously detected by cilia and basal-body high-throughput studies but never analyzed per se. Remarkably, this protein is also present in plants, which lack centrioles and cilia. Bug22p sequence alignments revealed consensus positions that distinguish species with centrioles/cilia from plants. In Paramecium, antibody and green fluorescent protein (GFP) fusion labeling localized Bug22p in basal bodies and cilia, and electron microscopy immunolabeling refined the localization to the terminal plate of the basal bodies, the transition zone, and spots along the axoneme, preferentially between the membrane and the microtubules. RNA interference (RNAi) depletion of Bug22p provoked a strong decrease in swimming speed, followed by cell death after a few days. High-speed video microscopy and morphological analysis of Bug22p-depleted cells showed that the protein plays an important role in the efficiency of ciliary movement by participating in the stroke shape and rigidity of cilia. The defects in cell swimming and growth provoked by RNAi can be complemented by expression of human Bug22p. This is the first reported case of complementation by a human gene in a ciliate. PMID:20118210

  3. Bug22p, a conserved centrosomal/ciliary protein also present in higher plants, is required for an effective ciliary stroke in Paramecium.

    Science.gov (United States)

    Laligné, C; Klotz, C; de Loubresse, N Garreau; Lemullois, M; Hori, M; Laurent, F X; Papon, J F; Louis, B; Cohen, J; Koll, F

    2010-04-01

    Centrioles, cilia, and flagella are ancestral conserved organelles of eukaryotic cells. Among the proteins identified in the proteomics of ciliary proteins in Paramecium, we focus here on a protein, Bug22p, previously detected by cilia and basal-body high-throughput studies but never analyzed per se. Remarkably, this protein is also present in plants, which lack centrioles and cilia. Bug22p sequence alignments revealed consensus positions that distinguish species with centrioles/cilia from plants. In Paramecium, antibody and green fluorescent protein (GFP) fusion labeling localized Bug22p in basal bodies and cilia, and electron microscopy immunolabeling refined the localization to the terminal plate of the basal bodies, the transition zone, and spots along the axoneme, preferentially between the membrane and the microtubules. RNA interference (RNAi) depletion of Bug22p provoked a strong decrease in swimming speed, followed by cell death after a few days. High-speed video microscopy and morphological analysis of Bug22p-depleted cells showed that the protein plays an important role in the efficiency of ciliary movement by participating in the stroke shape and rigidity of cilia. The defects in cell swimming and growth provoked by RNAi can be complemented by expression of human Bug22p. This is the first reported case of complementation by a human gene in a ciliate.

  4. Higher Education

    Science.gov (United States)

    & Development (LDRD) National Security Education Center (NSEC) Office of Science Programs Richard P Databases National Security Education Center (NSEC) Center for Nonlinear Studies Engineering Institute Scholarships STEM Education Programs Teachers (K-12) Students (K-12) Higher Education Regional Education

  5. 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)

    NARCIS (Netherlands)

    Robert, Vincent

    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

  6. Two UGT84 Family Glycosyltransferases Catalyze a Critical Reaction of Hydrolyzable Tannin Biosynthesis in Pomegranate (Punica granatum).

    Science.gov (United States)

    Ono, Nadia N; Qin, Xiaoqiong; Wilson, Alexander E; Li, Gang; Tian, Li

    2016-01-01

    Hydrolyzable tannins (HTs) play important roles in plant herbivore deterrence and promotion of human health. A critical step in HT production is the formation of 1-O-galloyl-β-D-glucopyranoside (β-glucogallin, ester-linked gallic acid and glucose) by a UDP-glucosyltransferase (UGT) activity. We cloned and biochemically characterized four candidate UGTs from pomegranate (Punica granatum), of which only UGT84A23 and UGT84A24 exhibited β-glucogallin forming activities in enzyme assays. Although overexpression and single RNAi knockdown pomegranate hairy root lines of UGT84A23 or UGT84A24 did not lead to obvious alterations in punicalagin (the prevalent HT in pomegranate) accumulation, double knockdown lines of the two UGTs resulted in largely reduced levels of punicalagins and bis-hexahydroxydiphenyl glucose isomers. An unexpected accumulation of galloyl glucosides (ether-linked gallic acid and glucose) was also detected in the double knockdown lines, suggesting that gallic acid was utilized by an unidentified UGT activity for glucoside formation. Transient expression in Nicotiana benthamiana leaves and immunogold labeling in roots of pomegranate seedlings collectively indicated cytosolic localization of UGT84A23 and UGT84A24. Overall, functional characterization and localization of UGT84A23 and UGT84A24 open up opportunities for further understanding the regulatory control of HT metabolism in plants and its coordination with other biochemical pathways in the metabolic network.

  7. Higher Education.

    Science.gov (United States)

    Hendrickson, Robert M.

    This chapter reports 1982 cases involving aspects of higher education. Interesting cases noted dealt with the federal government's authority to regulate state employees' retirement and raised the questions of whether Title IX covers employment, whether financial aid makes a college a program under Title IX, and whether sex segregated mortality…

  8. Photometric assay of maltose and maltose-forming enzyme activity by using 4-alpha-glucanotransferase (DPE2) from higher plants.

    Science.gov (United States)

    Smirnova, Julia; Fernie, Alisdair R; Spahn, Christian M T; Steup, Martin

    2017-09-01

    Maltose frequently occurs as intermediate of the central carbon metabolism of prokaryotic and eukaryotic cells. Various mutants possess elevated maltose levels. Maltose exists as two anomers, (α- and β-form) which are rapidly interconverted without requiring enzyme-mediated catalysis. As maltose is often abundant together with other oligoglucans, selective quantification is essential. In this communication, we present a photometric maltose assay using 4-alpha-glucanotransferase (AtDPE2) from Arabidopsis thaliana. Under in vitro conditions, AtDPE2 utilizes maltose as glucosyl donor and glycogen as acceptor releasing the other hexosyl unit as free glucose which is photometrically quantified following enzymatic phosphorylation and oxidation. Under the conditions used, DPE2 does not noticeably react with other di- or oligosaccharides. Selectivity compares favorably with that of maltase frequently used in maltose assays. Reducing end interconversion of the two maltose anomers is in rapid equilibrium and, therefore, the novel assay measures total maltose contents. Furthermore, an AtDPE2-based continuous photometric assay is presented which allows to quantify β-amylase activity and was found to be superior to a conventional test. Finally, the AtDPE2-based maltose assay was used to quantify leaf maltose contents of both Arabidopsis wild type and AtDPE2-deficient plants throughout the light-dark cycle. These data are presented together with assimilatory starch levels. Copyright © 2017. Published by Elsevier Inc.

  9. Phototropism and Protein Phosphorylation in Higher Plants: Unilateral Blue Light Irradiation Generates a Directional Gradient of Protein Phosphorylation Across the Oat Coleoptile

    International Nuclear Information System (INIS)

    Salomon, M.; Zacherl, M.; Rüdiger, W.

    1997-01-01

    Blue light induces the phosphorylation of a 116 kDa oat protein found in plasma membrane preparations from coleoptile tips. We developed a very sensitive in vitro method that allowed us to determine the tissue distribution of protein phosphorylation after applying unilateral and bilateral blue light pulses in vivo. We found that following unilateral in vivo irradiation the degree in phosphorylation of the 116 kDa protein is significantly higher at the irradiated than at the shaded side of the coleoptile tip. This asymmetry can be considered as previously missing criterion that protein phosphorylation represents an early event within the transduction chain for phototropism. (author)

  10. Root uptake of uranium (6) in solution by a higher plant: speciation in hydroponic solution, bioavailability, micro-localisation and biological effects induced

    International Nuclear Information System (INIS)

    Laroche, L.

    2005-01-01

    Uranium exists naturally in the environment, usually present in trace quantities. In soil solution and oxic conditions, uranium is present in the +VI oxidation state and forms a large number of inorganic and organic complexes. The exposure medium, an artificial soil solution, was designed in such a way as to control the uranium species in solution. The geochemical speciation code JCHESS was used to calculate the uranium aqueous species concentration and to define the domains of interest, each of them characterized by a limited number of dominant U species. These domains were defined as follows: pH 4.9 with uranyl ions as dominant species, pH 5.8 with hydroxyl complexes and pH 7 where carbonates play a major role. For each pH, short-duration (5 hours of exposure) well-defined laboratory experiments were carried out with Phaseolus vulgaris as plant model. The effect of competitive ions such as Ca 2+ or the presence of ligands such as phosphate or citrate on root assimilation efficiency was explored. Results have shown that uranium transfer was not affected by the presence of calcium, phosphate or citrate (but was decreased of 60% with citrate (10 μM) at pH 5.8) in our experimental conditions. Moreover, observation in Transmission Electronic Microscopy (TEM), equipped with an EDAX probe, have shown that uranium was associated with granules rich in phosphorus and that there were some chloroplast anomalies. Finally, the presence of uranium affects root CEC by reducing it and stimulates root elongation at low uranium concentrations (100 nM, 400 nM and 2 μM at pHs 4.9, 5.8 and 7 respectively) and inhibits it at high uranium concentrations. (author)

  11. Heat shock proteins of higher plants

    International Nuclear Information System (INIS)

    Key, J.L.; Lin, C.Y.; Chen, Y.M.

    1981-01-01

    The pattern of protein synthesis changes rapidly and dramatically when the growth temperture of soybean seedling tissue is increased from 28 0 C (normal) to about 40 0 C (heat shock). The synthesis of normal proteins is greatly decreased and a new set of proteins, heat shock proteins, is induced. The heat shock proteins of soybean consist of 10 new bands on one-dimensional NaDodSO 4 gels; a more complex pattern is observed on two-dimensional gels. when the tissue is returned to 28 0 C after 4 hr at 40 0 C, there is progressive decline in the synthesis of heat shock proteins and reappearance of a normal pattern of synthesis by 3 or 4 hr. In vitro translation of poly(A) + RNAs isolated from tissued grown at 28 and 40 0 C shows that the heat shock proteins are translated from a ndw set of mRNAs induced at 40 0 C; furthermore, the abundant class mRNAs for many of the normal proteins persist even though they are translated weakly (or not at all) in vivo at 40 or 42.5 0 C. The heat shock response in soybean appears similar to the much-studied heat shock phenomenon in Drosophila

  12. Electronic plants

    Science.gov (United States)

    Stavrinidou, Eleni; Gabrielsson, Roger; Gomez, Eliot; Crispin, Xavier; Nilsson, Ove; Simon, Daniel T.; Berggren, Magnus

    2015-01-01

    The roots, stems, leaves, and vascular circuitry of higher plants are responsible for conveying the chemical signals that regulate growth and functions. From a certain perspective, these features are analogous to the contacts, interconnections, devices, and wires of discrete and integrated electronic circuits. Although many attempts have been made to augment plant function with electroactive materials, plants’ “circuitry” has never been directly merged with electronics. We report analog and digital organic electronic circuits and devices manufactured in living plants. The four key components of a circuit have been achieved using the xylem, leaves, veins, and signals of the plant as the template and integral part of the circuit elements and functions. With integrated and distributed electronics in plants, one can envisage a range of applications including precision recording and regulation of physiology, energy harvesting from photosynthesis, and alternatives to genetic modification for plant optimization. PMID:26702448

  13. The binding of Xanthophylls to the bulk light-harvesting complex of photosystem II of higher plants. A specific requirement for carotenoids with a 3-hydroxy-beta-end group.

    Science.gov (United States)

    Phillip, Denise; Hobe, Stephan; Paulsen, Harald; Molnar, Peter; Hashimoto, Hideki; Young, Andrew J

    2002-07-12

    The pigment composition of the light-harvesting complexes (LHCs) of higher plants is highly conserved. The bulk complex (LHCIIb) binds three xanthophyll molecules in combination with chlorophyll (Chl) a and b. The structural requirements for binding xanthophylls to LHCIIb have been examined using an in vitro reconstitution procedure. Reassembly of the monomeric recombinant LHCIIb was performed using a wide range of native and nonnative xanthophylls, and a specific requirement for the presence of a hydroxy group at C-3 on a single beta-end group was identified. The presence of additional substituents (e.g. at C-4) did not interfere with xanthophyll binding, but they could not, on their own, support reassembly. cis isomers of zeaxanthin, violaxanthin, and lutein were not bound, whereas all-trans-neoxanthin and different chiral forms of lutein and zeaxanthin were incorporated into the complex. The C-3 and C-3' diols lactucaxanthin (a carotenoid native to many plant LHCs) and eschscholtzxanthin (a retro-carotenoid) both behaved very differently from lutein and zeaxanthin in that they would not support complex reassembly when used alone. Lactucaxanthin could, however, be bound when lutein was also present, and it showed a high affinity for xanthophyll binding site N1. In the presence of lutein, lactucaxanthin was readily bound to at least one lutein-binding site, suggesting that the ability to bind to the complex and initiate protein folding may be dependent on different structural features of the carotenoid molecule. The importance of carotenoid end group structure and ring-to-chain conformation around the C-6-C-7 torsion angle of the carotenoid molecule in binding and complex reassembly is discussed.

  14. Plant Research '75

    Energy Technology Data Exchange (ETDEWEB)

    1975-01-01

    Research is reported on stomatal regulation of the gas exchanges between plant and environment; inhibitory effects in flower formation; plant growth and development through hormones; hormone action; development and nitrogen fixation in algae; primary cell wall glycoprotein ectensin; enzymic mechanisms and control of polysaccharide and glycoprotein synthesis; molecular studies of membrane studies; sensory transduction in plants; regulation of formation of protein complexes and enzymes in higher plant cell and mechanism of sulfur dioxide toxicity in plants. (PCS)

  15. LNG plant combined with power plant

    Energy Technology Data Exchange (ETDEWEB)

    Aoki, I; Kikkawa, Y [Chiyoda Chemical Engineering and Construction Co. Ltd., Tokyo (Japan)

    1997-06-01

    The LNG plant consumers a lot of power of natural gas cooling and liquefaction. In some LNG plant location, a rapid growth of electric power demand is expected due to the modernization of area and/or the country. The electric power demand will have a peak in day time and low consumption in night time, while the power demand of the LNG plant is almost constant due to its nature. Combining the LNG plant with power plant will contribute an improvement the thermal efficiency of the power plant by keeping higher average load of the power plant, which will lead to a reduction of electrical power generation cost. The sweet fuel gas to the power plant can be extracted from the LNG plant, which will be favorable from view point of clean air of the area. (Author). 5 figs.

  16. LNG plant combined with power plant

    International Nuclear Information System (INIS)

    Aoki, I.; Kikkawa, Y.

    1997-01-01

    The LNG plant consumers a lot of power of natural gas cooling and liquefaction. In some LNG plant location, a rapid growth of electric power demand is expected due to the modernization of area and/or the country. The electric power demand will have a peak in day time and low consumption in night time, while the power demand of the LNG plant is almost constant due to its nature. Combining the LNG plant with power plant will contribute an improvement the thermal efficiency of the power plant by keeping higher average load of the power plant, which will lead to a reduction of electrical power generation cost. The sweet fuel gas to the power plant can be extracted from the LNG plant, which will be favorable from view point of clean air of the area. (Author). 5 figs

  17. Recent advances on the posttranslational modifications of EXTs and their roles in plant cell walls

    DEFF Research Database (Denmark)

    Velasquez, Melina; Salter, Juan Salgado; Dorosz, Javier Gloazzo

    2012-01-01

    The genetic set up and the enzymes that define the O-glycosylation sites and transfer the activated sugars to cell wall glycoprotein Extensins (EXTs) have remained unknown for a long time. We are now beginning to see the emerging components of the molecular machinery that assembles these complex O......-glycoproteins on the plant cell wall. Genes conferring the posttranslational modifications, i.e., proline hydroxylation and subsequent O-glycosylation, of the EXTs have been recently identified. In this review we summarize the enzymes that define the O-glycosylation sites on the O-glycoproteins, i.e., the prolyl 4......-hydroxylases (P4Hs), the glycosyltransferases that transfer arabinose units (named arabinosyltransferases, AraTs), and the one responsible for transferring a single galactose (galactosyltransferase, GalT) on the protein EXT backbones. We discuss the effects of posttranslational modifications on the structure...

  18. Molecular and functional analysis of phosphomannomutase (PMM) from higher plants and genetic evidence for the involvement of PMM in ascorbic acid biosynthesis in Arabidopsis and Nicotiana benthamiana

    DEFF Research Database (Denmark)

    Qian, W; Yu, C; Qin, H

    2007-01-01

    , soybean, tomato, rice and wheat. Amino acid sequence comparisons indicated that plant PMM proteins exhibited significant identity to their fungal and mammalian orthologs. In line with the similarity in primary structure, plant PMM complemented the sec53-6 temperature sensitive mutant of Saccharomyces...... was constitutively expressed in both vegetative and reproductive organs. Reducing the PMM expression level through virus-induced gene silencing caused a substantial decrease in ascorbic acid (AsA) content in N. benthamiana leaves. Conversely, raising the PMM expression level in N. benthamiana using viral......-vector-mediated ectopic expression led to a 20-50% increase in AsA content. Consistent with this finding, transgenic expression of an AtPMM-GFP fusion protein in Arabidopsis also increased AsA content by 25-33%. Collectively, this study improves our understanding on the molecular and functional properties of plant PMM...

  19. Overexpression of WsSGTL1 Gene of Withania somnifera Enhances Salt Tolerance, Heat Tolerance and Cold Acclimation Ability in Transgenic Arabidopsis Plants

    Science.gov (United States)

    Mishra, Manoj K.; Chaturvedi, Pankaj; Singh, Ruchi; Singh, Gaurav; Sharma, Lokendra K.; Pandey, Vibha; Kumari, Nishi; Misra, Pratibha

    2013-01-01

    Background Sterol glycosyltrnasferases (SGT) are enzymes that glycosylate sterols which play important role in plant adaptation to stress and are medicinally important in plants like Withania somnifera. The present study aims to find the role of WsSGTL1 which is a sterol glycosyltransferase from W. somnifera, in plant’s adaptation to abiotic stress. Methodology The WsSGTL1 gene was transformed in Arabidopsis thaliana through Agrobacterium mediated transformation, using the binary vector pBI121, by floral dip method. The phenotypic and physiological parameters like germination, root length, shoot weight, relative electrolyte conductivity, MDA content, SOD levels, relative electrolyte leakage and chlorophyll measurements were compared between transgenic and wild type Arabidopsis plants under different abiotic stresses - salt, heat and cold. Biochemical analysis was done by HPLC-TLC and radiolabelled enzyme assay. The promoter of the WsSGTL1 gene was cloned by using Genome Walker kit (Clontech, USA) and the 3D structures were predicted by using Discovery Studio Ver. 2.5. Results The WsSGTL1 transgenic plants were confirmed to be single copy by Southern and homozygous by segregation analysis. As compared to WT, the transgenic plants showed better germination, salt tolerance, heat and cold tolerance. The level of the transgene WsSGTL1 was elevated in heat, cold and salt stress along with other marker genes such as HSP70, HSP90, RD29, SOS3 and LEA4-5. Biochemical analysis showed the formation of sterol glycosides and increase in enzyme activity. When the promoter of WsSGTL1 gene was cloned from W. somnifera and sequenced, it contained stress responsive elements. Bioinformatics analysis of the 3D structure of the WsSGTL1 protein showed functional similarity with sterol glycosyltransferase AtSGT of A. thaliana. Conclusions Transformation of WsSGTL1 gene in A. thaliana conferred abiotic stress tolerance. The promoter of the gene in W.somnifera was found to have stress

  20. Root uptake of uranium (6) in solution by a higher plant: speciation in hydroponic solution, bioavailability, micro-localisation and biological effects induced; Transfert racinaire de l'uranium (6) en solution chez une plante superieure: speciation en solution hydroponique, prise en charge par la plante, microlocalisation et effets biologiques induits

    Energy Technology Data Exchange (ETDEWEB)

    Laroche, L

    2005-01-15

    Uranium exists naturally in the environment, usually present in trace quantities. In soil solution and oxic conditions, uranium is present in the +VI oxidation state and forms a large number of inorganic and organic complexes. The exposure medium, an artificial soil solution, was designed in such a way as to control the uranium species in solution. The geochemical speciation code JCHESS was used to calculate the uranium aqueous species concentration and to define the domains of interest, each of them characterized by a limited number of dominant U species. These domains were defined as follows: pH 4.9 with uranyl ions as dominant species, pH 5.8 with hydroxyl complexes and pH 7 where carbonates play a major role. For each pH, short-duration (5 hours of exposure) well-defined laboratory experiments were carried out with Phaseolus vulgaris as plant model. The effect of competitive ions such as Ca{sup 2+} or the presence of ligands such as phosphate or citrate on root assimilation efficiency was explored. Results have shown that uranium transfer was not affected by the presence of calcium, phosphate or citrate (but was decreased of 60% with citrate (10 {mu}M) at pH 5.8) in our experimental conditions. Moreover, observation in Transmission Electronic Microscopy (TEM), equipped with an EDAX probe, have shown that uranium was associated with granules rich in phosphorus and that there were some chloroplast anomalies. Finally, the presence of uranium affects root CEC by reducing it and stimulates root elongation at low uranium concentrations (100 nM, 400 nM and 2 {mu}M at pHs 4.9, 5.8 and 7 respectively) and inhibits it at high uranium concentrations. (author)

  1. Low-temperature conditioning of "seed" cloves enhances the expression of phenolic metabolism related genes and anthocyanin content in 'Coreano' garlic (Allium sativum) during plant development.

    Science.gov (United States)

    Dufoo-Hurtado, Miguel D; Zavala-Gutiérrez, Karla G; Cao, Cong-Mei; Cisneros-Zevallos, Luis; Guevara-González, Ramón G; Torres-Pacheco, Irineo; Vázquez-Barrios, M Estela; Rivera-Pastrana, Dulce M; Mercado-Silva, Edmundo M

    2013-11-06

    Low-temperature conditioning of garlic "seed" cloves accelerated the development of the crop cycle, decreased plant growth, and increased the synthesis of phenolic compounds and anthocyanins in the outer scale leaves of the bulbs at harvest time, leading to 3-fold content increase compared with those conditioned at room temperature. Cold conditioning of "seed" cloves also altered the anthocyanin profile during bulb development and at harvest. Two new anthocyanins are reported for the first time in garlic. The high phenolics and anthocyanin contents in bulbs of plants generated from "seed" cloves conditioned at 5 °C for 5 weeks were preceded by overexpression of some putative genes of the phenolic metabolism [6-fold for phenylalanine ammonia lyase (PAL)] and anthocyanin synthesis [1-fold for UDP-sugar:flavonoid 3-O-glycosyltransferase (UFGT)] compared with those conditioned at room temperature.

  2. Uptake and metabolism of diclofenac in Typha latifolia--how plants cope with human pharmaceutical pollution.

    Science.gov (United States)

    Bartha, Bernadett; Huber, Christian; Schröder, Peter

    2014-10-01

    The fate of pharmaceuticals in our environment is a very important issue for environmental and health research. Although these substances have been detected in environmental compartments in low concentration until now, they will pose considerable environmental risk to ecosystems, animals and human due to their biological activity. Alternative plant based removal technologies that make use of some potential wetland species like Phragmites or Typha within traditional wastewater treatment plants have to be established to cope with this "new generation" of pollutants. We investigated uptake and translocation of diclofenac (1mgl(-1)) in the macrophyte Typha latifolia L. during one week exposure in greenhouse experiments. Detoxification products and involved key enzymatic processes were identified. We also examined the oxidative stress induced by the treatment and the defense capacity of the plants. Rapid uptake and effective metabolism were observed, where glycoside and glutathione conjugates represent dominant metabolites. Up to seven-fold induction of glycosyltransferase activity was observed in roots, but not in shoots. Glutathione S-transferase activity was also induced, but to a lower extent. The activity changes of defense enzymes points to oxidative stress in the plants. Our results show that human pharmaceuticals can be metabolized by plants similar to xenobiotics, but that similarities to human metabolism are limited. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  3. Globalisation and Higher Education

    NARCIS (Netherlands)

    Marginson, Simon; van der Wende, Marijk

    2007-01-01

    Economic and cultural globalisation has ushered in a new era in higher education. Higher education was always more internationally open than most sectors because of its immersion in knowledge, which never showed much respect for juridical boundaries. In global knowledge economies, higher education

  4. Metodologia de seleção de cepas para produção etodologia da ciclodextrina glicosiltransferase e para purificação da enzima = Strains selection methodology for cyclodextrin glycosyltransferase production and enzyme purification

    Directory of Open Access Journals (Sweden)

    Glauciane de Lara Costa

    2007-01-01

    Full Text Available As ciclodextrinas (CDs são maltooligossacarídeos, produzidas a partir do amido, pela enzima ciclodextrina glicosiltransferase (CGTase. Esta pesquisa teve por objetivo estabelecer metodologias de seleção de cepas para produção de CGTase e para purificação da enzima. Os microrganismos foram selecionados a partir de 53 análises de solos de cultura de amido, em placas contendo meio de cultivo específico, para seleção de cepas produtoras de CGTase. As enzimas foram obtidas com cultivo destes microrganismos em meio líquido. As atividades enzimáticas das CGTases foram determinadas pelos métodos espectrofotométricos e precipitação com tricloroetileno. A cepa isolada do solo de aveia foi a que apresentou maior atividade [0,1864 mmol de b-CD (min mL-1]. Esta cepa foi utilizada para a produção da enzima em escala laboratorial e purificação em cromatografia deafinidade bioespecífica. A cepa selecionada nesta pesquisa abre novas perspectivas para produção de enzima e CDs em escala industrial.Cyclodextrins (CDs are maltooligosaccharides produced from starch by cyclodextrin glycosyltransferase (CGTase enzyme. This researchaimed at establishing method for strains selection for CGTase production and enzyme purification. The microorganisms were selected from 53 analyses of starch cultures soils on plates containing specific culture medium for strains selection that produce CGTase. Theenzymes were obtained by culturing these microorganisms in liquid medium. The enzyme activity was determined with photospectrometric methods and precipitation with trichloroethylene. The strain isolated from oat soil was the one that showed the highest activity [0.1864 mmol of b-CD (min mL-1]. This strain was used for enzyme production in laboratory scale and purification by biospecific affinity chromatography. The strain selected in this research opens new perspectives for enzymes production and CDs in industrial scale.

  5. Expression of microRNA-15b and the glycosyltransferase GCNT3 correlates with antitumor efficacy of Rosemary diterpenes in colon and pancreatic cancer.

    Directory of Open Access Journals (Sweden)

    Margarita González-Vallinas

    Full Text Available Colorectal and pancreatic cancers remain important contributors to cancer mortality burden and, therefore, new therapeutic approaches are urgently needed. Rosemary (Rosmarinus officinalis L. extracts and its components have been reported as natural potent antiproliferative agents against cancer cells. However, to potentially apply rosemary as a complementary approach for cancer therapy, additional information regarding the most effective composition, its antitumor effect in vivo and its main molecular mediators is still needed. In this work, five carnosic acid-rich supercritical rosemary extracts with different chemical compositions have been assayed for their antitumor activity both in vivo (in nude mice and in vitro against colon and pancreatic cancer cells. We found that the antitumor effect of carnosic acid together with carnosol was higher than the sum of their effects separately, which supports the use of the rosemary extract as a whole. In addition, gene and microRNA expression analyses have been performed to ascertain its antitumor mechanism, revealing that up-regulation of the metabolic-related gene GCNT3 and down-regulation of its potential epigenetic modulator miR-15b correlate with the antitumor effect of rosemary. Moreover, plasmatic miR-15b down-regulation was detected after in vivo treatment with rosemary. Our results support the use of carnosic acid-rich rosemary extract as a complementary approach in colon and pancreatic cancer and indicate that GCNT3 expression may be involved in its antitumor mechanism and that miR-15b might be used as a non-invasive biomarker to monitor rosemary anticancer effect.

  6. The carbon fertilization effect over a century of anthropogenic CO2 emissions: higher intracellular CO2 and more drought resistance among invasive and native grass species contrasts with increased water use efficiency for woody plants in the US Southwest.

    Science.gov (United States)

    Drake, Brandon L; Hanson, David T; Lowrey, Timothy K; Sharp, Zachary D

    2017-02-01

    From 1890 to 2015, anthropogenic carbon dioxide emissions have increased atmospheric CO 2 concentrations from 270 to 400 mol mol -1 . The effect of increased carbon emissions on plant growth and reproduction has been the subject of study of free-air CO 2 enrichment (FACE) experiments. These experiments have found (i) an increase in internal CO 2 partial pressure (c i ) alongside acclimation of photosynthetic capacity, (ii) variable decreases in stomatal conductance, and (iii) that increases in yield do not increase commensurate with CO 2 concentrations. Our data set, which includes a 115-year-long selection of grasses collected in New Mexico since 1892, is consistent with an increased c i as a response to historical CO 2 increase in the atmosphere, with invasive species showing the largest increase. Comparison with Palmer Drought Sensitivity Index (PDSI) for New Mexico indicates a moderate correlation with Δ 13 C (r 2  = 0.32, P < 0.01) before 1950, with no correlation (r 2  = 0.00, P = 0.91) after 1950. These results indicate that increased c i may have conferred some drought resistance to these grasses through increased availability of CO 2 in the event of reduced stomatal conductance in response to short-term water shortage. Comparison with C 3 trees from arid environments (Pinus longaeva and Pinus edulis in the US Southwest) as well as from wetter environments (Bromus and Poa grasses in New Mexico) suggests differing responses based on environment; arid environments in New Mexico see increased intrinsic water use efficiency (WUE) in response to historic elevated CO 2 while wetter environments see increased c i . This study suggests that (i) the observed increases in c i in FACE experiments are consistent with historical CO 2 increases and (ii) the CO 2 increase influences plant sensitivity to water shortage, through either increased WUE or c i in arid and wet environments, respectively. © 2016 John Wiley & Sons Ltd.

  7. Higher Education and Inequality

    Science.gov (United States)

    Brown, Roger

    2018-01-01

    After climate change, rising economic inequality is the greatest challenge facing the advanced Western societies. Higher education has traditionally been seen as a means to greater equality through its role in promoting social mobility. But with increased marketisation higher education now not only reflects the forces making for greater inequality…

  8. Higher Education in California

    Science.gov (United States)

    Public Policy Institute of California, 2016

    2016-01-01

    Higher education enhances Californians' lives and contributes to the state's economic growth. But population and education trends suggest that California is facing a large shortfall of college graduates. Addressing this short­fall will require strong gains for groups that have been historically under­represented in higher education. Substantial…

  9. Reimagining Christian Higher Education

    Science.gov (United States)

    Hulme, E. Eileen; Groom, David E., Jr.; Heltzel, Joseph M.

    2016-01-01

    The challenges facing higher education continue to mount. The shifting of the U.S. ethnic and racial demographics, the proliferation of advanced digital technologies and data, and the move from traditional degrees to continuous learning platforms have created an unstable environment to which Christian higher education must adapt in order to remain…

  10. Happiness in Higher Education

    Science.gov (United States)

    Elwick, Alex; Cannizzaro, Sara

    2017-01-01

    This paper investigates the higher education literature surrounding happiness and related notions: satisfaction, despair, flourishing and well-being. It finds that there is a real dearth of literature relating to profound happiness in higher education: much of the literature using the terms happiness and satisfaction interchangeably as if one were…

  11. Gender and Higher Education

    Science.gov (United States)

    Bank, Barbara J., Ed.

    2011-01-01

    This comprehensive, encyclopedic review explores gender and its impact on American higher education across historical and cultural contexts. Challenging recent claims that gender inequities in U.S. higher education no longer exist, the contributors--leading experts in the field--reveal the many ways in which gender is embedded in the educational…

  12. Quality of Higher Education

    DEFF Research Database (Denmark)

    Zou, Yihuan

    is about constructing a more inclusive understanding of quality in higher education through combining the macro, meso and micro levels, i.e. from the perspectives of national policy, higher education institutions as organizations in society, individual teaching staff and students. It covers both......Quality in higher education was not invented in recent decades – universities have always possessed mechanisms for assuring the quality of their work. The rising concern over quality is closely related to the changes in higher education and its social context. Among others, the most conspicuous...... changes are the massive expansion, diversification and increased cost in higher education, and new mechanisms of accountability initiated by the state. With these changes the traditional internally enacted academic quality-keeping has been given an important external dimension – quality assurance, which...

  13. [Effects of sulphur compounds on the volatile characteristics of heavy metals in fly ash from the MSW and sewage sludge co-combustion plant during the disposal process with higher temperature].

    Science.gov (United States)

    Liu, Jing-Yong; Sun, Shui-Yu

    2012-11-01

    Fly ash sample was collected from a MSW co-combustion with sewage sludge plant and the volatilization of heavy metals Pb, Cd, Cu and Zn was investigated before and after the water washing of fly ash, meanwhile, the influence of adding different sulphur compounds (S, NaS, Na2 SO3, Na2 SO4) on the volatilization of heavy metals was studied. The results showed that the contents of Zn, Pb and Mn were high, the Ni content was low and the Cd content reached 29.4 mg x kg(1). The contents of Pb, Cu, Zn increased, while that of Cd reduced in the fly ash after water washing. TG-DTG curves of fly ash showed highest weight loss in ranges of 579-732 degrees C and 949-1 200 degrees C, with 690 degrees C and 1 154 degrees C as the inflection point temperatures. The volatilization of different heavy metals showed great difference in the volatilization rate, following the order of Pb > Cd > Zn > Cu, in which the volatilization rate of Pb was more than 80% and that of Cu was less than 30%. After water washing, the volatilization of different heavy metals showed great difference in the volatilization rate, with the order of Zn > Pb > Cd > Cu, in which the volatilization rate of Zn was more than 20%. With the pretreatment of adding Na2 SO3 and Na2 SO4, the evaporation rates of heavy metals (Cu, Pb, Zn, Cd) were significantly decreased. After adding S, the evaporation rate of Zn was reduced, whereas the addition of Na2S reduced the evaporation rates of Cd and Zn. The evaporation rates of the four heavy metals were all reduced after adding Na2S in the washed fly ash. The evaporation rates of Cu and Zn were reduced with addition of S and Na2SO3 and the evaporation rate of Cd was reduced by adding the four sulfides. The results can provide a basis for the harmless disposal and maximized resource utilization and recycling of fly ash.

  14. Higher English for CFE

    CERN Document Server

    Bridges, Ann; Mitchell, John

    2015-01-01

    A brand new edition of the former Higher English: Close Reading , completely revised and updated for the new Higher element (Reading for Understanding, Analysis and Evaluation) - worth 30% of marks in the final exam!. We are working with SQA to secure endorsement for this title. Written by two highly experienced authors this book shows you how to practice for the Reading for Understanding, Analysis and Evaluation section of the new Higher English exam. This book introduces the terms and concepts that lie behind success and offers guidance on the interpretation of questions and targeting answer

  15. Multinationals and plant survival

    DEFF Research Database (Denmark)

    Bandick, Roger

    2010-01-01

    The aim of this paper is twofold: first, to investigate how different ownership structures affect plant survival, and second, to analyze how the presence of foreign multinational enterprises (MNEs) affects domestic plants’ survival. Using a unique and detailed data set on the Swedish manufacturing...... sector, I am able to separate plants into those owned by foreign MNEs, domestic MNEs, exporting non-MNEs, and purely domestic firms. In line with previous findings, the result, when conditioned on other factors affecting survival, shows that foreign MNE plants have lower survival rates than non......-MNE plants. However, separating the non-MNEs into exporters and non-exporters, the result shows that foreign MNE plants have higher survival rates than non-exporting non-MNEs, while the survival rates of foreign MNE plants and exporting non-MNE plants do not seem to differ. Moreover, the simple non...

  16. Planning for Higher Education.

    Science.gov (United States)

    Lindstrom, Caj-Gunnar

    1984-01-01

    Decision processes for strategic planning for higher education institutions are outlined using these parameters: institutional goals and power structure, organizational climate, leadership attitudes, specific problem type, and problem-solving conditions and alternatives. (MSE)

  17. Advert for higher education

    OpenAIRE

    N.V. Provozin; А.S. Teletov

    2011-01-01

    The article discusses the features advertising higher education institution. The analysis results of marketing research students for their choice of institutions and further study. Principles of the advertising campaign on three levels: the university, the faculty, the separate department.

  18. On higher derivative gravity

    International Nuclear Information System (INIS)

    Accioly, A.J.

    1987-01-01

    A possible classical route conducting towards a general relativity theory with higher-derivatives starting, in a sense, from first principles, is analysed. A completely causal vacuum solution with the symmetries of the Goedel universe is obtained in the framework of this higher-derivative gravity. This very peculiar and rare result is the first known vcuum solution of the fourth-order gravity theory that is not a solution of the corresponding Einstein's equations.(Author) [pt

  19. Higher Spins & Strings

    CERN Multimedia

    CERN. Geneva

    2014-01-01

    The conjectured relation between higher spin theories on anti de-Sitter (AdS) spaces and weakly coupled conformal field theories is reviewed. I shall then outline the evidence in favour of a concrete duality of this kind, relating a specific higher spin theory on AdS3 to a family of 2d minimal model CFTs. Finally, I shall explain how this relation fits into the framework of the familiar stringy AdS/CFT correspondence.

  20. What makes cyclodextrin glycosyltransferase a transglycosylase

    NARCIS (Netherlands)

    Leemhuis, Reinder Johannes

    2003-01-01

    All living organisms need energy from their environment for maintenance and growth. The carbohydrate starch is such an energy source. It is an abundant carbohydrate composed of amylose and amylopectin polymers. Before organisms can utilize the starch, it has to be degraded to smaller sugars suitable

  1. The origin and function of platelet glycosyltransferases

    DEFF Research Database (Denmark)

    Wandall, Hans H; Rumjantseva, Viktoria; Sørensen, Anne Louise Tølbøll

    2012-01-01

    Platelets are megakaryocyte subfragments that participate in hemostatic and host defense reactions and deliver pro- and anti-angiogenic factors throughout the vascular system. Platelets are anucleated cells and lack a complex secretory apparatus with distinct Golgi/endoplasmic reticulum compartme...

  2. What sugar next? Dimerization of sphingolipid glycosyltransferases

    NARCIS (Netherlands)

    van Meer, G.

    2001-01-01

    One of the great riddles of glycobiology is the function of the glycosphingolipids. Their vital role is clear from the fact that the lack only of subsets of glycosphingolipids results in premature death (1). Hundreds of glycosphingolipids populate the surface of mammalian cells. These may serve a

  3. Fuel Class Higher Alcohols

    KAUST Repository

    Sarathy, Mani

    2016-08-17

    This chapter focuses on the production and combustion of alcohol fuels with four or more carbon atoms, which we classify as higher alcohols. It assesses the feasibility of utilizing various C4-C8 alcohols as fuels for internal combustion engines. Utilizing higher-molecular-weight alcohols as fuels requires careful analysis of their fuel properties. ASTM standards provide fuel property requirements for spark-ignition (SI) and compression-ignition (CI) engines such as the stability, lubricity, viscosity, and cold filter plugging point (CFPP) properties of blends of higher alcohols. Important combustion properties that are studied include laminar and turbulent flame speeds, flame blowout/extinction limits, ignition delay under various mixing conditions, and gas-phase and particulate emissions. The chapter focuses on the combustion of higher alcohols in reciprocating SI and CI engines and discusses higher alcohol performance in SI and CI engines. Finally, the chapter identifies the sources, production pathways, and technologies currently being pursued for production of some fuels, including n-butanol, iso-butanol, and n-octanol.

  4. Higher spin gauge theories

    CERN Document Server

    Henneaux, Marc; Vasiliev, Mikhail A

    2017-01-01

    Symmetries play a fundamental role in physics. Non-Abelian gauge symmetries are the symmetries behind theories for massless spin-1 particles, while the reparametrization symmetry is behind Einstein's gravity theory for massless spin-2 particles. In supersymmetric theories these particles can be connected also to massless fermionic particles. Does Nature stop at spin-2 or can there also be massless higher spin theories. In the past strong indications have been given that such theories do not exist. However, in recent times ways to evade those constraints have been found and higher spin gauge theories have been constructed. With the advent of the AdS/CFT duality correspondence even stronger indications have been given that higher spin gauge theories play an important role in fundamental physics. All these issues were discussed at an international workshop in Singapore in November 2015 where the leading scientists in the field participated. This volume presents an up-to-date, detailed overview of the theories i...

  5. INTERNATIONALIZATION IN HIGHER EDUCATION

    Directory of Open Access Journals (Sweden)

    Catalina Crisan-Mitra

    2016-03-01

    Full Text Available Internationalization of higher education is one of the key trends of development. There are several approaches on how to achieve competitiveness and performance in higher education and international academic mobility; students’ exchange programs, partnerships are some of the aspects that can play a significant role in this process. This paper wants to point out the student’s perception regarding two main directions: one about the master students’ expectation regarding how an internationalized master should be organized and should function, and second the degree of satisfaction of the beneficiaries of internationalized master programs from Babe-Bolyai University. This article is based on an empirical qualitative research that was implemented to students of an internationalized master from the Faculty of Economics and Business Administration. This research can be considered a useful example for those preoccupied to increase the quality of higher education and conclusions drawn have relevance both theoretically and especially practically.

  6. Quality of Higher Education

    DEFF Research Database (Denmark)

    Zou, Yihuan; Zhao, Yingsheng; Du, Xiangyun

    . This transformation involves a broad scale of change at individual level, organizational level, and societal level. In this change process in higher education, staff development remains one of the key elements for university innovation and at the same time demands a systematic and holistic approach.......This paper starts with a critical approach to reflect on the current practice of quality assessment and assurance in higher education. This is followed by a proposal that in response to the global challenges for improving the quality of higher education, universities should take active actions...... of change by improving the quality of teaching and learning. From a constructivist perspective of understanding education and learning, this paper also discusses why and how universities should give more weight to learning and change the traditional role of teaching to an innovative approach of facilitation...

  7. Reputation in Higher Education

    DEFF Research Database (Denmark)

    Martensen, Anne; Grønholdt, Lars

    2005-01-01

    leaders of higher education institutions to set strategic directions and support their decisions in an effort to create even better study programmes with a better reputation. Finally, managerial implications and directions for future research are discussed.Keywords: Reputation, image, corporate identity......The purpose of this paper is to develop a reputation model for higher education programmes, provide empirical evidence for the model and illustrate its application by using Copenhagen Business School (CBS) as the recurrent case. The developed model is a cause-and-effect model linking image...

  8. Reputation in Higher Education

    DEFF Research Database (Denmark)

    Plewa, Carolin; Ho, Joanne; Conduit, Jodie

    2016-01-01

    Reputation is critical for institutions wishing to attract and retain students in today's competitive higher education setting. Drawing on the resource based view and configuration theory, this research proposes that Higher Education Institutions (HEIs) need to understand not only the impact...... of independent resources but of resource configurations when seeking to achieve a strong, positive reputation. Utilizing fuzzy set qualitative comparative analysis (fsQCA), the paper provides insight into different configurations of resources that HEIs can utilize to build their reputation within their domestic...

  9. Navigating in higher education

    DEFF Research Database (Denmark)

    Thingholm, Hanne Balsby; Reimer, David; Keiding, Tina Bering

    Denne rapport er skrevet på baggrund af spørgeskemaundersøgelsen – Navigating in Higher Education (NiHE) – der rummer besvarelser fra 1410 bachelorstuderende og 283 undervisere fordelt på ni uddannelser fra Aarhus Universitet: Uddannelsesvidenskab, Historie, Nordisk sprog og litteratur, Informati......Denne rapport er skrevet på baggrund af spørgeskemaundersøgelsen – Navigating in Higher Education (NiHE) – der rummer besvarelser fra 1410 bachelorstuderende og 283 undervisere fordelt på ni uddannelser fra Aarhus Universitet: Uddannelsesvidenskab, Historie, Nordisk sprog og litteratur...

  10. The plant secretory pathway seen through the lens of the cell wall.

    Science.gov (United States)

    van de Meene, A M L; Doblin, M S; Bacic, Antony

    2017-01-01

    Secretion in plant cells is often studied by looking at well-characterised, evolutionarily conserved membrane proteins associated with particular endomembrane compartments. Studies using live cell microscopy and fluorescent proteins have illuminated the highly dynamic nature of trafficking, and electron microscopy studies have resolved the ultrastructure of many compartments. Biochemical and molecular analyses have further informed about the function of particular proteins and endomembrane compartments. In plants, there are over 40 cell types, each with highly specialised functions, and hence potential variations in cell biological processes and cell wall structure. As the primary function of secretion in plant cells is for the biosynthesis of cell wall polysaccharides and apoplastic transport complexes, it follows that utilising our knowledge of cell wall glycosyltransferases (GTs) and their polysaccharide products will inform us about secretion. Indeed, this knowledge has led to novel insights into the secretory pathway, including previously unseen post-TGN secretory compartments. Conversely, our knowledge of trafficking routes of secretion will inform us about polarised and localised deposition of cell walls and their constituent polysaccharides/glycoproteins. In this review, we look at what is known about cell wall biosynthesis and the secretory pathway and how the different approaches can be used in a complementary manner to study secretion and provide novel insights into these processes.

  11. 大豆玉米“扩行增密”带状复种技术在山西应用初探%Application of ‘ Entend Row and Higher Density’ Strip Compound Planting System of Soybean-Maize in Shanxi Province

    Institute of Scientific and Technical Information of China (English)

    刘小荣; 马俊奎; 刘学义

    2017-01-01

    为确定大豆玉米“扩行增密”带状复种技术在山西的增产效果及筛选适宜的大豆品种,应用大豆品种汾豆78与玉米品种大丰30研究了山西省传统玉米大豆套作模式与大豆玉米“扩行增密”带状复种技术对比,应用大豆品种汾豆78、79、56、92及93与玉米品种大丰30进行了大豆新品种筛选.测定了大豆苗期、盛花期、结荚期的叶绿素含量和干物质积累,大豆成熟后的品质,大豆玉米成熟后的植株性状和产量.结果表明:大豆玉米“扩行增密”带状复种技术与传统套作模式相比,带状复种技术下大豆植株总叶绿素、籽粒蛋白质及油脂含量更高,蛋白质和油脂含量分别为42.28%和19.84%,大豆与玉米产量分别为531.0和9 514.5 kg·hm-2,分别增产6.6%和70.7%.大豆新品种筛选结果显示,汾豆93在植株生长后期干物质及叶绿素含量最高,植株性状最佳,成熟后籽粒的品质最好,蛋白质和油脂含量分别为44.08%和20.2%,玉米大豆综合产量最高,大豆和玉米的产量分别为894.0及10 550.7 kg·hm-2,比对照组分别增产了68.7%和10.9%.表明这种大豆玉米“扩行增密”带状复种技术适合在山西省生态环境条件下应用推广,汾豆93与大丰30是“扩行增密”带状复种模式较好的搭配品种.%In order to investigate the application of ‘ entend row and higher density’ strip compound planting system of soybean-maize in Shanxi province,and screen out suitable soybean cultivars,we carried out a contrastive study of ‘ extend row and higher density’ strip compound planting system of soybean-maize and the traditional interplanting mode in Shanxi which used Fendou 78 and Dafeng 30,and selected five cultivars Fendou 78,79,56,92 and 93 suitable for the strip compound planting system.Then we determined the chlorophyll content,dry matter accumulation of soybean at seedling stage,flowering stage and seed filling period

  12. Exploring Higher Thinking.

    Science.gov (United States)

    Conover, Willis M.

    1992-01-01

    Maintains that the social studies reform movement includes a call for the de-emphasis of rote memory and more attention to the development of higher-order thinking skills. Discusses the "thinking tasks" concept derived from the work of Hilda Taba and asserts that the tasks can be used with almost any social studies topic. (CFR)

  13. Higher-Order Hierarchies

    DEFF Research Database (Denmark)

    Ernst, Erik

    2003-01-01

    This paper introduces the notion of higher-order inheritance hierarchies. They are useful because they provide well-known benefits of object-orientation at the level of entire hierarchies-benefits which are not available with current approaches. Three facets must be adressed: First, it must be po...

  14. Inflation from higher dimensions

    International Nuclear Information System (INIS)

    Shafi, Q.

    1987-01-01

    We argue that an inflationary phase in the very early universe is related to the transition from a higher dimensional to a four-dimensional universe. We present details of a previously considered model which gives sufficient inflation without fine tuning of parameters. (orig.)

  15. Higher Education Funding Formulas.

    Science.gov (United States)

    McKeown-Moak, Mary P.

    1999-01-01

    One of the most critical components of the college or university chief financial officer's job is budget planning, especially using formulas. A discussion of funding formulas looks at advantages, disadvantages, and types of formulas used by states in budgeting for higher education, and examines how chief financial officers can position the campus…

  16. Liberty and Higher Education.

    Science.gov (United States)

    Thompson, Dennis F.

    1989-01-01

    John Stuart Mill's principle of liberty is discussed with the view that it needs to be revised to guide moral judgments in higher education. Three key elements need to be modified: the action that is constrained; the constraint on the action; and the agent whose action is constrained. (MLW)

  17. Fuel Class Higher Alcohols

    KAUST Repository

    Sarathy, Mani

    2016-01-01

    This chapter focuses on the production and combustion of alcohol fuels with four or more carbon atoms, which we classify as higher alcohols. It assesses the feasibility of utilizing various C4-C8 alcohols as fuels for internal combustion engines

  18. Evaluation in Higher Education

    Science.gov (United States)

    Bognar, Branko; Bungic, Maja

    2014-01-01

    One of the means of transforming classroom experience is by conducting action research with students. This paper reports about the action research with university students. It has been carried out within a semester of the course "Methods of Upbringing". Its goal has been to improve evaluation of higher education teaching. Different forms…

  19. Higher-level Innovization

    DEFF Research Database (Denmark)

    Bandaru, Sunith; Tutum, Cem Celal; Deb, Kalyanmoy

    2011-01-01

    we introduce the higher-level innovization task through an application of a manufacturing process simulation for the Friction Stir Welding (FSW) process where commonalities among two different Pareto-optimal fronts are analyzed. Multiple design rules are simultaneously deciphered from each front...

  20. Benchmarking for Higher Education.

    Science.gov (United States)

    Jackson, Norman, Ed.; Lund, Helen, Ed.

    The chapters in this collection explore the concept of benchmarking as it is being used and developed in higher education (HE). Case studies and reviews show how universities in the United Kingdom are using benchmarking to aid in self-regulation and self-improvement. The chapters are: (1) "Introduction to Benchmarking" (Norman Jackson…

  1. Creativity in Higher Education

    Science.gov (United States)

    Gaspar, Drazena; Mabic, Mirela

    2015-01-01

    The paper presents results of research related to perception of creativity in higher education made by the authors at the University of Mostar from Bosnia and Herzegovina. This research was based on a survey conducted among teachers and students at the University. The authors developed two types of questionnaires, one for teachers and the other…

  2. California's Future: Higher Education

    Science.gov (United States)

    Johnson, Hans

    2015-01-01

    California's higher education system is not keeping up with the changing economy. Projections suggest that the state's economy will continue to need more highly educated workers. In 2025, if current trends persist, 41 percent of jobs will require at least a bachelor's degree and 36 percent will require some college education short of a bachelor's…

  3. Cyberbullying in Higher Education

    Science.gov (United States)

    Minor, Maria A.; Smith, Gina S.; Brashen, Henry

    2013-01-01

    Bullying has extended beyond the schoolyard into online forums in the form of cyberbullying. Cyberbullying is a growing concern due to the effect on its victims. Current studies focus on grades K-12; however, cyberbullying has entered the world of higher education. The focus of this study was to identify the existence of cyberbullying in higher…

  4. Competitiveness - higher education

    Directory of Open Access Journals (Sweden)

    Labas Istvan

    2016-03-01

    Full Text Available Involvement of European Union plays an important role in the areas of education and training equally. The member states are responsible for organizing and operating their education and training systems themselves. And, EU policy is aimed at supporting the efforts of member states and trying to find solutions for the common challenges which appear. In order to make our future sustainable maximally; the key to it lies in education. The highly qualified workforce is the key to development, advancement and innovation of the world. Nowadays, the competitiveness of higher education institutions has become more and more appreciated in the national economy. In recent years, the frameworks of operation of higher education systems have gone through a total transformation. The number of applying students is continuously decreasing in some European countries therefore only those institutions can “survive” this shortfall, which are able to minimize the loss of the number of students. In this process, the factors forming the competitiveness of these budgetary institutions play an important role from the point of view of survival. The more competitive a higher education institution is, the greater the chance is that the students would like to continue their studies there and thus this institution will have a greater chance for the survival in the future, compared to ones lagging behind in the competition. Aim of our treatise prepared is to present the current situation and main data of the EU higher education and we examine the performance of higher education: to what extent it fulfils the strategy for smart, sustainable and inclusive growth which is worded in the framework of Europe 2020 programme. The treatise is based on analysis of statistical data.

  5. Higher Education Language Policy

    DEFF Research Database (Denmark)

    Lauridsen, Karen M.

    2013-01-01

    Summary of recommendations HEIs are encouraged, within the framework of their own societal context, mission, vision and strategies, to develop the aims and objectives of a Higher Education Language Policy (HELP) that allows them to implement these strategies. In this process, they may want......: As the first step in a Higher Education Language Policy, HEIs should determine the relative status and use of the languages employed in the institution, taking into consideration the answers to the following questions:  What is/are the official language(s) of the HEI?  What is/are the language...... and the level of internationalisation the HEI has or wants to have, and as a direct implication of that, what are the language proficiency levels expected from the graduates of these programme?  Given the profile of the HEI and its educational strategies, which language components are to be offered within...

  6. Characterization of the vacuolar H sup + -ATPase of higher plants

    Energy Technology Data Exchange (ETDEWEB)

    Manolson, M F

    1988-01-01

    The tonoplast H{sup +}-ATPase of Beta vulgaris L. was partially purified by Triton X-100 solubilization and Sepharose 4B chromatography resulting in the enrichment of two polypeptides. Kinetic analysis of ({alpha}-{sup 32}P) BzATP labeling identified the 57 kDa polypeptide as a nucleotide-binding subunit with a possible regulatory function. In addition, ({sup 14}C) DCCD-labeling identified a 16 kDa polypeptide as a putative transmembrane proton channel. It is concluded that the tonoplast H{sup +}-ATPase is a multimer composed of at least three polypeptides. Anti-57 and anti-67 kDa sera reacted with polypeptides of the corresponding size in bovine chromaffin granules, bovine clathrin-coated vesicles, and yeast vacuolar membranes, suggesting common structural features and common ancestry for endomembrane H{sup +}-ATPase of different organelles and different phyla. Anti-57 serum was used to isolate a cDNA encoding the corresponding subunit from Arabidopsis. Protein sequence analysis revealed homologies between endomembrane, F{sub 0}F{sub 1} and archaebacterial ATPases, suggesting that these different classes of ATPases have evolved from a common ancestor.

  7. Monitoring ambient air for mutagenicity using the higher plant Tradescantia

    International Nuclear Information System (INIS)

    Schairer, L.A.; Sautkulis, R.C.; Tempel, N.R.

    1982-01-01

    The major emphasis for short-term bioassays has been placed on bacterial and mammalian cell lines. However, for increased perspective on the state-of-the-art of specific in vitro assays it is important to consider the environmental impact on whole organisms by reviewing the contributions made by in vivo assays. This paper will deal exclusively with somatic mutation in the Tradescantia stamen hair: describing the system briefly, demonstrating its relevance to environmental mutagen assessment and discussing its adaptation for in situ ambient atmosphere monitoring

  8. Higher value in litigation for nuclear power plant proceedings

    International Nuclear Information System (INIS)

    Anon.

    1976-01-01

    The administrative court of Bavaria has rejected in its ruling of 19th August 1976 - No. 117 VI 76 - an appeal against the fixing of the value in litigation according to the judgment of the administrative court in Wuerzburg of 10th March 1976, and it has confirmed DM 20,000 as the disputed sum. The essential points of the grounds upon which the rejection is based are presented. (orig./HP) [de

  9. Melatonin in higher plants: occurrence and possible functions

    Czech Academy of Sciences Publication Activity Database

    Kolář, Jan; Macháčková, Ivana

    2005-01-01

    Roč. 39, - (2005), s. 333-341 ISSN 0742-3098 Institutional research plan: CEZ:AV0Z50380511 Keywords : Melatonin * Lingulodinium * auxin-like effects Subject RIV: ED - Physiology Impact factor: 5.025, year: 2005

  10. Radiochemistry in nuclear power plants

    International Nuclear Information System (INIS)

    Schwarz, W.

    2007-01-01

    Radiochemistry is employed in nuclear power plants not as an end in itself but, among other things, as a main prerequisite of optimum radiation protection. Radiochemical monitoring of various loops provides important information about sources of radioactivity, activity distribution in the plant and its changes. In the light of these analytical findings, plant crews are able to take measures having a positive effect on radiation levels in the plant. The example of a BWR plant is used to show, among other things, how radiochemical analyses helped to reduce radiation levels in a plant and, as a consequence, to decrease clearly radiation exposure of the personnel despite higher workloads. (orig.)

  11. Populations in clonal plants

    Directory of Open Access Journals (Sweden)

    Jussi Tammisola

    1986-12-01

    Full Text Available Population phenomena in higher plants are reviewed critically, particularly in relation to clonality. An array of concepts used in the field are discussed. In contrast to animals, higher plants are modular in structure. Plant populations show hierarchy at two levels: ramets and genets. In addition, their demography is far more complicated, since even the direction of development of a ramet may change by rejuvenation. Therefore, formulae concerning animal populations often require modification for plants. Furthermore, at the zygotic stage, higher plants are generally less mobile than animals. Accordingly, their population processes tend to be more local. Most populations of plants have a genetic structure: alleles and genotypes are spatially aggregated. Due to the short-ranged foraging behaviour of pollinators, genetically non-random pollination prevails. A generalized formula for parent-offspring dispersal variance is derived. It is used to analyze the effect of clonality on genetic patchiness in populations. In self-compatible species, an increase in clonality will tend to increase the degree of patchiness, while in self-incompatible species a decrease may result. Examples of population structure studies in different species are presented. A considerable degree of genetic variation appears to be found also in the populations of species with a strong allocation of resources to clonal growth or apomictic seed production. Some consequences of clonality are considered from the point of view of genetic conservation and plant breeding.

  12. Higher Education in Scandinavia

    DEFF Research Database (Denmark)

    Nielsen, Jørgen Lerche; Andreasen, Lars Birch

    2015-01-01

    Higher education systems around the world have been undergoing fundamental changes through the last 50 years from more narrow self-sustaining universities for the elite and into mass universities, where new groups of students have been recruited and the number of students enrolled has increased...... an impact on the educational systems in Scandinavia, and what possible futures can be envisioned?...... dramatically. In adjusting to the role of being a mass educational institution, universities have been challenged on how to cope with external pressures, such as forces of globalization and international markets, increased national and international competition for students and research grants, increased...

  13. Higher engineering mathematics

    CERN Document Server

    John Bird

    2014-01-01

    A practical introduction to the core mathematics principles required at higher engineering levelJohn Bird's approach to mathematics, based on numerous worked examples and interactive problems, is ideal for vocational students that require an advanced textbook.Theory is kept to a minimum, with the emphasis firmly placed on problem-solving skills, making this a thoroughly practical introduction to the advanced mathematics engineering that students need to master. The extensive and thorough topic coverage makes this an ideal text for upper level vocational courses. Now in

  14. Integrated Gasification SOFC Plant with a Steam Plant

    DEFF Research Database (Denmark)

    Rokni, Masoud; Pierobon, Leonardo

    2011-01-01

    A hybrid Solid Oxide Fuel Cell (SOFC) and Steam Turbine (ST) plant is integrated with a gasification plant. Wood chips are fed to the gasification plant to produce biogas and then this gas is fed into the anode side of a SOFC cycle to produce electricity and heat. The gases from the SOFC stacks...... enter into a burner to burn the rest of the fuel. The offgases after the burner are now used to generate steam in a Heat Recovery Steam Generator (HRSG). The generated steam is expanded in a ST to produce additional power. Thus a triple hybrid plant based on a gasification plant, a SOFC plant...... and a steam plant is presented and studied. The plant is called as IGSS (Integrated Gasification SOFC Steam plant). Different systems layouts are presented and investigated. Electrical efficiencies up to 56% are achieved which is considerably higher than the conventional integrated gasification combined...

  15. Towards higher intensities

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    Over the past 2 weeks, commissioning of the machine protection system has advanced significantly, opening up the possibility of higher intensity collisions at 3.5 TeV. The intensity has been increased from 2 bunches of 1010 protons to 6 bunches of 2x1010 protons. Luminosities of 6x1028 cm-2s-1 have been achieved at the start of fills, a factor of 60 higher than those provided for the first collisions on 30 March.   The recent increase in LHC luminosity as recorded by the experiments. (Graph courtesy of the experiments and M. Ferro-Luzzi) To increase the luminosity further, the commissioning crews are now trying to push up the intensity of the individual proton bunches. After the successful injection of nominal intensity bunches containing 1.1x1011 protons, collisions were subsequently achieved at 450 GeV with these intensities. However, half-way through the first ramping of these nominal intensity bunches to 3.5 TeV on 15 May, a beam instability was observed, leading to partial beam loss...

  16. Teaching at higher levels

    Science.gov (United States)

    1998-11-01

    Undergraduate physics programmes for the 21st century were under discussion at a recent event held in Arlington, USA, open to two or three members of the physics faculties of universities from across the whole country. The conference was organized by the American Association of Physics Teachers with co-sponsorship from the American Institute of Physics, the American Physical Society and Project Kaleidoscope. Among the various aims were to learn about physics departments that have successfully revitalized their undergraduate physics programmes with innovative introductory physics courses and multi-track majors programmes. Engineers and life scientists were to be asked directly how physics programmes can better serve their students, and business leaders would be speaking on how physics departments can help to prepare their students for the diverse careers that they will eventually follow. It was planned to highlight ways that departments could fulfil their responsibilities towards trainee teachers, to identify the resources needed for revitalizing a department's programme, and to develop guidelines and recommendations for a funding programme to support collaborative efforts among physics departments for carrying out the enhancements required. More details about the conference can be found on the AAPT website (see http://www.aapt.org/programs/rupc.html). Meanwhile the UK's Higher Education Funding Council has proposed a two-pronged approach to the promotion of high quality teaching and learning, as well as widening participation in higher education from 1999-2000. A total of £60m should be available to support these initiatives by the year 2001-2002. As part of this scheme the Council will invite bids from institutions to support individual academics in enhancing learning and teaching, as well as in recognition of individual excellence. As with research grants, such awards would enable staff to pursue activities such as the development of teaching materials

  17. Higher Order Mode Fibers

    DEFF Research Database (Denmark)

    Israelsen, Stine Møller

    This PhD thesis considers higher order modes (HOMs) in optical fibers. That includes their excitation and characteristics. Within the last decades, HOMs have been applied both for space multiplexing in optical communications, group velocity dispersion management and sensing among others......-radial polarization as opposed to the linear polarization of the LP0X modes. The effect is investigated numerically in a double cladding fiber with an outer aircladding using a full vectorial modesolver. Experimentally, the bowtie modes are excited using a long period grating and their free space characteristics...... and polarization state are investigated. For this fiber, the onset of the bowtie effect is shown numerically to be LP011. The characteristics usually associated with Bessel-likes modes such as long diffraction free length and selfhealing are shown to be conserved despite the lack of azimuthal symmetry...

  18. Spiky higher genus strings

    International Nuclear Information System (INIS)

    Ambjoern, J.; Bellini, A.; Johnston, D.

    1990-10-01

    It is clear from both the non-perturbative and perturbative approaches to two-dimensional quantum gravity that a new strong coupling regime is setting in at d=1, independent of the genus of the worldsheet being considered. It has been suggested that a Kosterlitz-Thouless (KT) phase transition in the Liouville theory is the cause of this behaviour. However, it has recently been pointed out that the XY model, which displays a KT transition on the plane and the sphere, is always in the strong coupling, disordered phase on a surface of constant negative curvature. A higher genus worldsheet can be represented as a fundamental region on just such a surface, which might seem to suggest that the KT picture predicts a strong coupling region for arbitrary d, contradicting the known results. We resolve the apparent paradox. (orig.)

  19. Comparative analysis of fungal genomes reveals different plant cell wall degrading capacity in fungi

    Science.gov (United States)

    2013-01-01

    Background Fungi produce a variety of carbohydrate activity enzymes (CAZymes) for the degradation of plant polysaccharide materials to facilitate infection and/or gain nutrition. Identifying and comparing CAZymes from fungi with different nutritional modes or infection mechanisms may provide information for better understanding of their life styles and infection models. To date, over hundreds of fungal genomes are publicly available. However, a systematic comparative analysis of fungal CAZymes across the entire fungal kingdom has not been reported. Results In this study, we systemically identified glycoside hydrolases (GHs), polysaccharide lyases (PLs), carbohydrate esterases (CEs), and glycosyltransferases (GTs) as well as carbohydrate-binding modules (CBMs) in the predicted proteomes of 103 representative fungi from Ascomycota, Basidiomycota, Chytridiomycota, and Zygomycota. Comparative analysis of these CAZymes that play major roles in plant polysaccharide degradation revealed that fungi exhibit tremendous diversity in the number and variety of CAZymes. Among them, some families of GHs and CEs are the most prevalent CAZymes that are distributed in all of the fungi analyzed. Importantly, cellulases of some GH families are present in fungi that are not known to have cellulose-degrading ability. In addition, our results also showed that in general, plant pathogenic fungi have the highest number of CAZymes. Biotrophic fungi tend to have fewer CAZymes than necrotrophic and hemibiotrophic fungi. Pathogens of dicots often contain more pectinases than fungi infecting monocots. Interestingly, besides yeasts, many saprophytic fungi that are highly active in degrading plant biomass contain fewer CAZymes than plant pathogenic fungi. Furthermore, analysis of the gene expression profile of the wheat scab fungus Fusarium graminearum revealed that most of the CAZyme genes related to cell wall degradation were up-regulated during plant infection. Phylogenetic analysis also

  20. Wind power plant

    Energy Technology Data Exchange (ETDEWEB)

    Caneghem, A.E. von

    1975-07-24

    The invention applies to a wind power plant in which the wind is used to drive windmills. The plant consists basically of a vertical tube with a lateral wind entrance opening with windmill on its lower end. On its upper end, the tube carries a nozzle-like top which increases the wind entering the tube by pressure decrease. The wind is thus made suitable for higher outputs. The invention is illustrated by constructional examples.

  1. Learning higher mathematics

    CERN Document Server

    Pontrjagin, Lev Semenovič

    1984-01-01

    Lev Semenovic Pontrjagin (1908) is one of the outstanding figures in 20th century mathematics. In a long career he has made fundamental con­ tributions to many branches of mathematics, both pure and applied. He has received every honor that a grateful government can bestow. Though in no way constrained to do so, he has through the years taught mathematics courses at Moscow State University. In the year 1975 he set himself the task of writing a series of books on secondary school and beginning university mathematics. In his own words, "I wished to set forth the foundations of higher mathematics in a form that would have been accessible to myself as a lad, but making use of all my experience as a scientist and a teacher, ac­ cumulated over many years. " The present volume is a translation of the first two out of four moderately sized volumes on this theme planned by Pro­ fessor Pontrjagin. The book begins at the beginning of modern mathematics, analytic ge­ ometry in the plane and 3-dimensional space. Refin...

  2. TOR signalling in plants.

    Science.gov (United States)

    Rexin, Daniel; Meyer, Christian; Robaglia, Christophe; Veit, Bruce

    2015-08-15

    Although the eukaryotic TOR (target of rapamycin) kinase signalling pathway has emerged as a key player for integrating nutrient-, energy- and stress-related cues with growth and metabolic outputs, relatively little is known of how this ancient regulatory mechanism has been adapted in higher plants. Drawing comparisons with the substantial knowledge base around TOR kinase signalling in fungal and animal systems, functional aspects of this pathway in plants are reviewed. Both conserved and divergent elements are discussed in relation to unique aspects associated with an autotrophic mode of nutrition and adaptive strategies for multicellular development exhibited by plants. © 2015 Authors; published by Portland Press Limited.

  3. Experimental mutagenesis in plants

    International Nuclear Information System (INIS)

    Conger, B.V.

    1979-01-01

    Considerable progress has been made in directed or controlled mutagenesis with bacterial systems, the genetic resolving power of which is much greater than that of higher plants. The mutagen specificity in higher plants has been of great interest, and numerous results and observations have been reported. The advances in the culture of plant cells and tissues have created much interest concerning the possibility of inducing and recovering mutants at the cellular level. There are great problems including the failure to regenerate plants from cells in all but a few species. The genetic and cytogenetic instability in the culture of plant tissues is well known, and the most common nuclear change is polyploidy including aneuploidy. The degree of polyploidy increases with calluses or culture age. In rice, the frequency of aneuploidy is greater in the calluses derived from roots than those derived from stem internodes. Polyploid and/or self-incompatible plant species are not as amenable to conventional mutation breeding techniques as diploid, self-fertilizing species. Inducing mutations in somatic tissues creates the problem of chimeras. However, the new cultivars of highly heterozygous, outcrossing, self-incompatible species are produced by combining several different clones. The performance of the progeny of at least 4 generations removed from the polycross of the parent clones is the important factor, and a high amount of heterozygocity is tolerated within cultivars and even on the same plants. (Yamashita, S.)

  4. Higher Efficiency HVAC Motors

    Energy Technology Data Exchange (ETDEWEB)

    Flynn, Charles Joseph [QM Power, Inc., Kansas City, MO (United States)

    2018-02-13

    failure prone capacitors from the power stage. Q-Sync’s simpler electronics also result in higher efficiency because it eliminates the power required by the PCB to perform the obviated power conversions and PWM processes after line synchronous operating speed is reached in the first 5 seconds of operation, after which the PWM circuits drop out and a much less energy intensive “pass through” circuit takes over, allowing the grid-supplied AC power to sustain the motor’s ongoing operation.

  5. Medicinal Plants.

    Science.gov (United States)

    Phillipson, J. David

    1997-01-01

    Highlights the demand for medicinal plants as pharmaceuticals and the demand for health care treatments worldwide and the issues that arise from this. Discusses new drugs from plants, anticancer drugs, antiviral drugs, antimalarial drugs, herbal remedies, quality, safety, efficacy, and conservation of plants. Contains 30 references. (JRH)

  6. Towards Multi Fuel SOFC Plant

    DEFF Research Database (Denmark)

    Rokni, Masoud; Clausen, Lasse Røngaard; Bang-Møller, Christian

    2011-01-01

    Complete Solid Oxide Fuel Cell (SOFC) plants fed by several different fuels are suggested and analyzed. The plants sizes are about 10 kW which is suitable for single family house with needs for both electricity and heat. Alternative fuels such as, methanol, DME (Di-Methyl Ether) and ethanol...... are also considered and the results will be compared with the base plant fed by Natural Gas (NG). A single plant design will be suggested that can be fed with methanol, DME and ethanol whenever these fuels are available. It will be shown that the plant fed by ethanol will have slightly higher electrical...

  7. Plant walkdown

    International Nuclear Information System (INIS)

    Kostov, M.

    2000-01-01

    This report covers the following: preparatory steps for performing plant walk-down; the objective of the first plant walk-down; plant walk-down procedures; earthquake screening evaluation; walk-down documentation; second plant walk-down. The following objectives concerning the plant walk-down(s) were achieved. The plant system configuration is verified in order to proceed with event tree and fault tree analyses. Systems interactions, other types of dependencies or plant unique features are identified. he safety related components that are judged to generically possess high capacities (i.e., larger than the earthquake review level) have been verified to contain no weaknesses. Further analyses needed to establish the capacities of remaining safety-related components are identified and necessary field data are obtained. Information on components is obtained to assist in HCLPF (fragility) evaluation and peer review of the seismic margin study

  8. Aquatic plants

    DEFF Research Database (Denmark)

    Madsen, T. V.; Sand-Jensen, K.

    2006-01-01

    Aquatic fl owering plants form a relatively young plant group on an evolutionary timescale. The group has developed over the past 80 million years from terrestrial fl owering plants that re-colonised the aquatic environment after 60-100 million years on land. The exchange of species between terre...... terrestrial and aquatic environments continues today and is very intensive along stream banks. In this chapter we describe the physical and chemical barriers to the exchange of plants between land and water.......Aquatic fl owering plants form a relatively young plant group on an evolutionary timescale. The group has developed over the past 80 million years from terrestrial fl owering plants that re-colonised the aquatic environment after 60-100 million years on land. The exchange of species between...

  9. Advances in genetics. Volume 22: Molecular genetics of plants

    International Nuclear Information System (INIS)

    Scandalios, J.G.; Caspari, E.W.

    1984-01-01

    This book contains the following four chapters: Structural Variation in Mitochondrial DNA; The Structure and Expression of Nuclear Genes in Higher Plants; Chromatin Structure and Gene Regulation in Higher Plants; and The Molecular Genetics of Crown Gall Tumorigenesis

  10. Plant embryogenesis

    NARCIS (Netherlands)

    Vries, de Sacco C.; Weijers, Dolf

    2017-01-01

    Land plants are called ‘embryophytes’ and thus, their collective name is defined by their ability to form embryos. Indeed, embryogenesis is a widespread phenomenon in plants, and much of our diet is composed of embryos (just think of grains, beans or nuts; Figure 1). However, in addition to embryos

  11. Makerere Journal of Higher Education

    African Journals Online (AJOL)

    Makerere Journal of Higher Education (MAJOHE) is the official publication of ... management and improvement of higher education from an international viewpoint. ... Historical Development of Science and Technology Education in Nigeria: ...

  12. Internationalization of Chinese Higher Education

    Science.gov (United States)

    Chen, Linhan; Huang, Danyan

    2013-01-01

    This paper probes into the development of internationalization of higher education in China from ancient times to modern times, including the emergence of international connections in Chinese higher education and the subsequent development of such connections, the further development of internationalization of Chinese higher education, and the…

  13. A Tax for Higher Education

    Science.gov (United States)

    Blumenstyk, Goldie

    2012-01-01

    Higher education pays off handsomely for society. Yet on a nationwide basis, states' support for higher education per full-time-equivalent student has fallen to just $6,290, the lowest in 15 years. A dedicated source of funds for higher education is problematic. But what if state and federal lawmakers applied the impeccable logic of the gas tax to…

  14. Enzymes from Higher Eukaryotes for Industrial Biocatalysis

    Directory of Open Access Journals (Sweden)

    Zhibin Liu

    2004-01-01

    Full Text Available The industrial production of fine chemicals, feed and food ingredients, pharmaceuticals, agrochemicals and their respective intermediates relies on an increasing application of biocatalysis, i.e. on enzyme or whole-cell catalyzed conversions of molecules. Simple procedures for discovery, cloning and over-expression as well as fast growth favour fungi, yeasts and especially bacteria as sources of biocatalysts. Higher eukaryotes also harbour an almost unlimited number of potential biocatalysts, although to date the limited supply of enzymes, the high heterogeneity of enzyme preparations and the hazard of infectious contaminants keep some interesting candidates out of reach for industrial bioprocesses. In the past only a few animal and plant enzymes from agricultural waste materials were employed in food processing. The use of bacterial expression strains or non-conventional yeasts for the heterologous production of efficient eukaryotic enzymes can overcome the bottleneck in enzyme supply and provide sufficient amounts of homogenous enzyme preparations for reliable and economically feasible applications at large scale. Ideal enzymatic processes represent an environmentally friendly, »near-to-completion« conversion of (mostly non-natural substrates to pure products. Recent developments demonstrate the commercial feasibility of large-scale biocatalytic processes employing enzymes from higher eukaryotes (e.g. plants, animals and also their usefulness in some small-scale industrial applications.

  15. [Distribution of HCB discharged from a chemical plant in plants].

    Science.gov (United States)

    Chen, Jing; Wang, Lin-Ling; Lu, Xiao-Hua; Yuan, Song-Hu; Liu, Xi-Xiang; Wang, Yue; Zhao, Qian; Mei, Ling-Fang

    2009-04-15

    The distribution characteristics of hexachlorobenzene (HCB) in plant and rhizosphere soil in contamination conduit, a nearby river and a cropland were studied and the impact factors were also discussed. The results are summarized as follows: the range of the HCB concentration in plant and rhizosphere soil in investigation area were respectively from 4.45 microg x kg(-1) to 1,189.89 microg x kg(-1) (dw) and from 27.93 microg x kg(-1) to 3,480.71 microg x kg(-1) (dw). Higher enrichment of HCB in woodplant than herbs due to higher fat concentration in woodplant in the contamination conduit and the rich concentrtion factor of woodplant and herbs were 0.41-2.55 and 0.01-1.34. The range of HCB concentrations in plants in nearby croplands was significantly wide (4.45-333.1 microg x kg(-1)) while HCB concentrations in different parts of plant were various, e.g. HCB concentrations in fruit, root and shoot of taro were 318.77 microg x kg(-1), 281.02 microg x kg(-1) and 10.94 microg x kg(-1). There was a remarkable positive relation between the concentrations of HCB in plant and fat concentration of plant while no relativity between the concentrations of HCB in plant and those in ground soils in the contamination conduit and cropland. The concentration levels of HCB in plant and rhizosphere soil in river were dramatically decreased with increasing distance from contaminated conduit. There was a remarkable positive relation between the concentrations of HCB in plant and those in ground soils but no relation between concentrations of HCB in plant and fat concentration of plant in river. The distribution characteristics of HCB in plants were influenced by contaminated levels, fat concentration and Partition-transfer model.

  16. Biofuelled heating plants

    International Nuclear Information System (INIS)

    Gulliksson, Hans; Wennerstaal, L.; Zethraeus, B.; Johansson, Bert-Aake

    2001-11-01

    filters. Fabric filters or electrical partition filters is needed to meet the environment requirements for the larger plants in this effect range. If the need for guidelines for environment requirement is great, the need for technical guidelines is even greater. Existing technical requirement or guidelines are relatively few and there is room for improvement and development. This report suggests not only technical requirements for design but also for controlling devices. Development efforts to create simple, dependable and cost effective systems for operation control (among other things CO, O 2 , NO x , dust efficiency, fuel moisture content) is needed to further increase the knowledge of the plants in the smaller effect range 0,3 to 10 MW. To extract more energy from the fuel, flue gas condensing is now recommended to a higher extent. This means that the energy of the vaporized moisture in the flue gas is recycled, and obtained at no extra cost, considering the amount of fuel used. The report contains combustion and environment requirement suggestions with basis in results from measurement at a number of existing plants. These refer to emissions of carbon monoxide, nitric oxides, total organic carbon and dust. The report also contains suggestions of water quality requirement after flue gas condensing, and noise level requirements. The report also contains an illustrating example of how to implement plant control to ensure that operational decisions and environmental legislation are followed. This example is based on the Swedish Environmental Protection Agency's general advice and handbook on plant control. The report's suggestions on technical design, how to meet environment requirements, training and help handbooks will hopefully simplify the practical tasks, such as construction, purchasing and operation of bio fuelled plants, and result in a continued phase-out of fossil fuels

  17. Chemical defence and toxins of plants

    NARCIS (Netherlands)

    Yamane, H.; Konno, K.; Sabelis, M.; Takabayashi, J.; Sassa, T.; Oikawa, H.; Mander, L.; Lui, H.W.

    2010-01-01

    Higher plants protect themselves by producing a variety of secondary metabolites and proteins that are involved in defense against herbivores as well as microbial pathogens. Concerning microbial pathogenesis in plants, in many cases, it is known that phytotoxins that are produced by plant pathogens

  18. Plants. Ag Ed Environmental Education Series.

    Science.gov (United States)

    Tulloch, Rodney W.

    Designed to serve as a resource tool in a high school vocational agriculture curriculum dealing with the environment as it relates to agriculture, this unit is concerned with plants. Plants are defined and their characteristics described. A section on the effects of environment on higher plants covers temperature, light, water, nutrients, air,…

  19. Plant Macrofossils

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Records of past vegetation and environmental change derived from plant remains large enough to be seen without a microscope (macrofossils), such as leaves, needles,...

  20. T Plant

    Data.gov (United States)

    Federal Laboratory Consortium — Arguably the second most historic building at Hanford is the T Plant.This facility is historic in that it's the oldest remaining nuclear facility in the country that...

  1. Lunar Plants

    Data.gov (United States)

    National Aeronautics and Space Administration — We present an open design for a first plant growth module on the Moon (LPX). The primary science goal of lunar habitat is to investigate germination and initial...

  2. Alien plants

    Science.gov (United States)

    2018-04-01

    No-one’s ever travelled to an extrasolar planet, or even observed one that we’re sure harbours life. But if plants do exist on such alien worlds, we can have fun speculating what form they might take.

  3. Plant simulator

    International Nuclear Information System (INIS)

    Fukumitsu, Hiroyuki

    1998-01-01

    A simulator of a reactor plant of the present invention comprises a plurality of distributed computers, an indication processing section and an operation section. The simulation calculation functions of various kinds of plant models in the plant are shared by the plurality of computers. The indication processing section controls collection of data of the plant simulated by the computers and instructions of an operator. The operation section is operated by the operator and the results of operation are transmitted to the indication processing section, to conduct operation trainings and display the results of the simulation. Each of the computers and the indication processing portion are connected with each other by a network having a memory for common use. Data such as the results of calculation of plant models and various kinds of parameters of the plant required commonly to the calculators and the indication processing section are stored in the common memory, and adapted to be used by way of the network. (N.H.)

  4. Strategic Planning for Higher Education.

    Science.gov (United States)

    Kotler, Philip; Murphy, Patrick E.

    1981-01-01

    The framework necessary for achieving a strategic planning posture in higher education is outlined. The most important benefit of strategic planning for higher education decision makers is that it forces them to undertake a more market-oriented and systematic approach to long- range planning. (Author/MLW)

  5. Effective Communication in Higher Education

    Science.gov (United States)

    Howard, Melissa

    2014-01-01

    The intent for this paper is to show that communication within the higher education field is a current problem. By looking first at the different styles, forms, and audiences for communication, the reader will hopefully gain perspective as to why this is such a problem in higher education today. Since the Millennial generation is the newest set of…

  6. Higher Education, Poverty and Development

    Science.gov (United States)

    Tilak, Jandhyala B. G.

    2010-01-01

    There is a presumption among many policy makers that higher education is not necessary for economic growth and development; it is literacy and basic education and at best secondary education that are argued to be important. Estimates of internal rate of return contributed to strengthening of such a presumption. Accordingly, higher education has…

  7. Women in Higher Education Administration.

    Science.gov (United States)

    Association of American Colleges, Washington, DC. Project on the Status and Education of Women.

    Two papers are presented that examine the barriers to women in academic decision making and identify a variety of effective strategies for improving the status of women in higher education administration. "Strategies for Advancing Women in Higher Education Administration," by Garry D. Hays, proposes that commitment to increasing the…

  8. The Marketing of Higher Education.

    Science.gov (United States)

    Brooker, George; Noble, Michael

    1985-01-01

    Formal college and university marketing programs are challenging to develop and implement because of the complexity of the marketing mix, the perceived inappropriateness of a traditional marketing officer, the number of diverse groups with input, the uniqueness of higher education institutions, and the difficulty in identifying higher education…

  9. Higher Education and Ethical Value

    Science.gov (United States)

    Lee, Jeong-Kyu

    2017-01-01

    The purpose of this study is to explore the importance of ethical value in higher education as well as the relevance between ethical value and higher education. In order to examine the study logically, three research questions are addressed: First, what is value, ethical value, and Asiatic ethical value? Second, for whom and what is higher…

  10. Exploring Higher Education Financing Options

    Science.gov (United States)

    Nkrumah-Young, Kofi K.; Powell, Philip

    2011-01-01

    Higher education can be financed privately, financed by governments, or shared. Given that the benefits of education accrue to the individual and the state, many governments opt for shared financing. This article examines the underpinnings of different options for financing higher education and develops a model to compare conditions to choices and…

  11. Disruptive Technologies in Higher Education

    Science.gov (United States)

    Flavin, Michael

    2012-01-01

    This paper analyses the role of "disruptive" innovative technologies in higher education. In this country and elsewhere, Higher Education Institutions (HEIs) have invested significant sums in learning technologies, with Virtual Learning Environments (VLEs) being more or less universal, but these technologies have not been universally…

  12. Higher Education, Employability and Competitiveness

    Science.gov (United States)

    Pavlin, Samo; Svetlicic, Marjan

    2012-01-01

    This paper studies the relationship between competitiveness and higher education systems in Europe. It explores whether more competitive countries have developed more labour-market-oriented systems of higher education (HE) that thereby give their graduates greater short term employability potential. Based on and a large-scale survey among 45.000…

  13. Learning Entrepreneurship in Higher Education

    Science.gov (United States)

    Taatila, Vesa P.

    2010-01-01

    Purpose: There is a constant need to produce more entrepreneurial graduates from higher education institutions. This paper aims to present and discuss several successful cases of entrepreneurial learning environments in order to suggest some important aspects that higher education institutions should consider. Design/methodology/approach: The…

  14. Feminist Research in Higher Education

    Science.gov (United States)

    Ropers-Huilman, Rebecca; Winters, Kelly T.

    2011-01-01

    This essay provides an overview of feminist methodology and its potential to enhance the study of higher education. Foregrounding the multiple purposes and research relationships developed through feminist research, the essay urges higher education scholars to engage feminist theories, epistemologies, and methods to inform policy, research, and…

  15. Queering Transformation in Higher Education

    Science.gov (United States)

    Msibi, Thabo

    2013-01-01

    Transformation in higher education has tended to focus on race and sex, at the expense of other forms of discrimination. This article addresses the silencing of "queer" issues in higher education. Using queer theory as a framework, and drawing on current literature, popular media reports, two personal critical incidents and a project…

  16. Leading Change in Higher Education

    Science.gov (United States)

    McRoy, Ian; Gibbs, Paul

    2009-01-01

    This article considers the situation in the UK higher education system and investigates specifically the leadership practice in a cluster of UK institutions as they changed their status. The research goes further to advocate a form of contextualized leadership that is relevant to higher institutions under change. (Contains 1 figure.)

  17. Higher Education: Open for Business

    Science.gov (United States)

    Gilde, Christian, Ed.

    2007-01-01

    This book addresses a problem in higher learning, which is newly recognized in the academic spotlight: the overcommercialization of higher education. The book asks that you, the reader, think about the following: Did you go to a Coke or Pepsi school? Do your children attend a Nike or Adidas school? Is the college in your town a Dell or Gateway…

  18. Polish Higher Education: Intersectoral Distinctiveness

    Science.gov (United States)

    Musial, Joanna

    2014-01-01

    This study analyzes degrees of differences between the private and public sectors of Polish higher education. It finds them to be strong: Polish private institutions function very differently from Polish public institutions and these differences correspond with those found in the literature on higher education elsewhere in the world. Polish…

  19. Innovations in Higher Education? Hah!

    Science.gov (United States)

    Kirschner, Ann

    2012-01-01

    One can hardly mention higher education today without hearing the word "innovation," or its understudies "change," "reinvention," "transformation." Last summer the National Governors Association opened its meeting with a plenary session on higher education, innovation, and economic growth. But there is nothing funny about the need for innovation…

  20. Fact Book on Higher Education

    Science.gov (United States)

    Marks, Joseph L.; Diaz, Alicia A.

    2009-01-01

    The "Southern Regional Education Board (SREB) Fact Book on Higher Education" is one of the nation's most comprehensive collections of comparative data on higher education. For decades, state leaders, policy-makers, researchers and journalists have used the "Fact Book" to find useful data quickly--and to learn more about…

  1. Higher Franz-Reidemeister torsion

    CERN Document Server

    Igusa, Kiyoshi

    2002-01-01

    The book is devoted to the theory of topological higher Franz-Reidemeister torsion in K-theory. The author defines the higher Franz-Reidemeister torsion based on Volodin's K-theory and Borel's regulator map. He describes its properties and generalizations and studies the relation between the higher Franz-Reidemeister torsion and other torsions used in K-theory: Whitehead torsion and Ray-Singer torsion. He also presents methods of computing higher Franz-Reidemeister torsion, illustrates them with numerous examples, and describes various applications of higher Franz-Reidemeister torsion, particularly for the study of homology of mapping class groups. Packed with up-to-date information, the book provides a unique research and reference tool for specialists working in algebraic topology and K-theory.

  2. Microorganism and filamentous fungi drive evolution of plant synapses.

    Science.gov (United States)

    Baluška, František; Mancuso, Stefano

    2013-01-01

    In the course of plant evolution, there is an obvious trend toward an increased complexity of plant bodies, as well as an increased sophistication of plant behavior and communication. Phenotypic plasticity of plants is based on the polar auxin transport machinery that is directly linked with plant sensory systems impinging on plant behavior and adaptive responses. Similar to the emergence and evolution of eukaryotic cells, evolution of land plants was also shaped and driven by infective and symbiotic microorganisms. These microorganisms are the driving force behind the evolution of plant synapses and other neuronal aspects of higher plants; this is especially pronounced in the root apices. Plant synapses allow synaptic cell-cell communication and coordination in plants, as well as sensory-motor integration in root apices searching for water and mineral nutrition. These neuronal aspects of higher plants are closely linked with their unique ability to adapt to environmental changes.

  3. Plant automation

    International Nuclear Information System (INIS)

    Christensen, L.J.; Sackett, J.I.; Dayal, Y.; Wagner, W.K.

    1989-01-01

    This paper describes work at EBR-II in the development and demonstration of new control equipment and methods and associated schemes for plant prognosis, diagnosis, and automation. The development work has attracted the interest of other national laboratories, universities, and commercial companies. New initiatives include use of new control strategies, expert systems, advanced diagnostics, and operator displays. The unique opportunity offered by EBR-II is as a test bed where a total integrated approach to automatic reactor control can be directly tested under real power plant conditions

  4. Teaching Creatively in Higher Education

    DEFF Research Database (Denmark)

    Chemi, Tatiana; Zhou, Chunfang

    The topic of this booklet is a synthesis of relevant research in the field of creativity in higher education, with focus on creative teaching methods. By means of literature review and research findings this booklet describes a wide range of contexts and effects on student learning and develop­me......­ment, together with teacher motivation and overall satisfaction. This booklet meets the need for renewal and creation in higher education, in order to address the challenges of the future, focusing on the benefits of teaching crea­tively at higher education.......The topic of this booklet is a synthesis of relevant research in the field of creativity in higher education, with focus on creative teaching methods. By means of literature review and research findings this booklet describes a wide range of contexts and effects on student learning and develop...

  5. Categorification and higher representation theory

    CERN Document Server

    Beliakova, Anna

    2017-01-01

    The emergent mathematical philosophy of categorification is reshaping our view of modern mathematics by uncovering a hidden layer of structure in mathematics, revealing richer and more robust structures capable of describing more complex phenomena. Categorified representation theory, or higher representation theory, aims to understand a new level of structure present in representation theory. Rather than studying actions of algebras on vector spaces where algebra elements act by linear endomorphisms of the vector space, higher representation theory describes the structure present when algebras act on categories, with algebra elements acting by functors. The new level of structure in higher representation theory arises by studying the natural transformations between functors. This enhanced perspective brings into play a powerful new set of tools that deepens our understanding of traditional representation theory. This volume exhibits some of the current trends in higher representation theory and the diverse te...

  6. The Legalization of Higher Education

    Science.gov (United States)

    Badke, Lara K.

    2017-01-01

    A complete discussion of intellectual property (IP), faculty rights, and the public good requires a thorough framing of higher education's legal context, from which the rise of legalistic criteria (or legalization) and current IP regime have grown.

  7. Scientific collaboratories in higher education

    DEFF Research Database (Denmark)

    Sonnenwald, Diane H.; Li, Bin

    2003-01-01

    Scientific collaboratories hold the promise of providing students access to specialized scientific instruments, data and experts, enabling learning opportunities perhaps otherwise not available. However, evaluation of scientific collaboratories in higher education has lagged behind...

  8. Progressive problems higher grade physics

    CERN Document Server

    Kennedy, William

    2001-01-01

    This book fully covers all three Units studied in Scotland's Higher Grade Physics course, providing a systematic array of problems (from the simplest to the most difficult) to lead variously abled pupils to examination success.

  9. Quality Management in Higher Education

    OpenAIRE

    Svoboda, Petr

    2017-01-01

    The thesis deals with quality management theory as an important part of management science. The primary objective of this work is an identification, formulation and analysis of such managerial issues in quality of higher education, which either are not known, or whose resolution is not considered fully sufficient. The thesis contains a bibliography of more than 200 related scientific works and presents selected issues of quality management in higher education, such as quality perception or it...

  10. Black Holes in Higher Dimensions

    Directory of Open Access Journals (Sweden)

    Reall Harvey S.

    2008-09-01

    Full Text Available We review black-hole solutions of higher-dimensional vacuum gravity and higher-dimensional supergravity theories. The discussion of vacuum gravity is pedagogical, with detailed reviews of Myers–Perry solutions, black rings, and solution-generating techniques. We discuss black-hole solutions of maximal supergravity theories, including black holes in anti-de Sitter space. General results and open problems are discussed throughout.

  11. Plant-based remediation processes

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Dharmendra Kumar (ed.) [Belgian Nuclear Research Centre (SCK.CEN), Mol (Belgium). Radiological Impact and Performance Assessment Division

    2013-11-01

    A valuable source of information for scientists in the field of environmental pollution and remediation. Describes the latest biotechnological methods for the treatment of contaminated soils. Includes case studies and protocols. Phytoremediation is an emerging technology that employs higher plants for the clean-up of contaminated environments. Basic and applied research have unequivocally demonstrated that selected plant species possess the genetic potential to accumulate, degrade, metabolize and immobilize a wide range of contaminants. The main focus of this volume is on the recent advances of technologies using green plants for remediation of various metals and metalloids. Topics include biomonitoring of heavy metal pollution, amendments of higher uptake of toxic metals, transport of heavy metals in plants, and toxicity mechanisms. Further chapters discuss agro-technological methods for minimizing pollution while improving soil quality, transgenic approaches to heavy metal remediation and present protocols for metal remediation via in vitro root cultures.

  12. Plant intelligence

    Science.gov (United States)

    Lipavská, Helena; Žárský, Viktor

    2009-01-01

    The concept of plant intelligence, as proposed by Anthony Trewavas, has raised considerable discussion. However, plant intelligence remains loosely defined; often it is either perceived as practically synonymous to Darwinian fitness, or reduced to a mere decorative metaphor. A more strict view can be taken, emphasizing necessary prerequisites such as memory and learning, which requires clarifying the definition of memory itself. To qualify as memories, traces of past events have to be not only stored, but also actively accessed. We propose a criterion for eliminating false candidates of possible plant intelligence phenomena in this stricter sense: an “intelligent” behavior must involve a component that can be approximated by a plausible algorithmic model involving recourse to stored information about past states of the individual or its environment. Re-evaluation of previously presented examples of plant intelligence shows that only some of them pass our test. “You were hurt?” Kumiko said, looking at the scar. Sally looked down. “Yeah.” “Why didn't you have it removed?” “Sometimes it's good to remember.” “Being hurt?” “Being stupid.”—(W. Gibson: Mona Lisa Overdrive) PMID:19816094

  13. PLANT DIVERSITY

    Science.gov (United States)

    Habitat change statistics and species-area curves were used to estimate the effects of alternative future scenarios for agriculture on plant diversity in Iowa farmlands. Study areas were two watersheds in central Iowa of about 50 and 90 square kilometers, respectively. Future s...

  14. Approaches to translational plant science

    DEFF Research Database (Denmark)

    Dresbøll, Dorte Bodin; Christensen, Brian; Thorup-Kristensen, Kristian

    2015-01-01

    is lessened. In our opinion, implementation of translational plant science is a necessity in order to solve the agricultural challenges of producing food and materials in the future. We suggest an approach to translational plant science forcing scientists to think beyond their own area and to consider higher......Translational science deals with the dilemma between basic research and the practical application of scientific results. In translational plant science, focus is on the relationship between agricultural crop production and basic science in various research fields, but primarily in the basic plant...... science. Scientific and technological developments have allowed great progress in our understanding of plant genetics and molecular physiology, with potentials for improving agricultural production. However, this development has led to a separation of the laboratory-based research from the crop production...

  15. FACEBOOK COMMUNICATION IN HIGHER EDUCATION

    Directory of Open Access Journals (Sweden)

    Emanuela Maria AVRAM

    2014-11-01

    Full Text Available The social networks have been growing steadily in recent years. Facebook, one of the most popular social networks, is a modern means of communication and socialization that has taken lately more ground in higher education becoming an important academic tool in the communication process. Many universities have their own Facebook page, being used by both students and teachers, and creating Facebook groups increasingly facilitates communication with students. Thus, this paper aims to identify the importance that Facebook holds in the academic communication process and highlights the implications it has in higher education. The results reveal that this type of communication has gained more ground in academia creating real social communities, and students use it more and more for collaboration in various activities involved in the higher education system, but also for socializing and information.

  16. PV integration into a CSP plant

    Science.gov (United States)

    Carvajal, Javier López; Barea, Jose M.; Barragan, Jose; Ortega, Carlos

    2017-06-01

    This paper describes a preliminary techno-economic analysis of the integration of a PV plant into an optimized Parabolic Trough Plant in order to reduce the online consumptions and thus, increase the net electricity injected into the grid. The idea is to assess the feasibility of such project and see what configuration would be the optimal. An extra effort has been made in terms of modelling as the analysis has to be done to the integrated CSP + PV plant instead of analyzing them independently. Two different technologies have been considered for the PV plant, fix and one-axis tracking. Additionally three different scenarios have been considered for the CSP plant auxiliary consumptions as they are essential for determining the optimal PV plant (the higher the auxiliary consumption the higher the optimal PV plant). As could be expected, the results for all cases with PV show an improvement in terms of electricity generation and also in terms of LCOE with respect to the CSP plant. Such improvement is slightly higher with tracking technology for this specific study. Although this exercise has been done to an already designed CSP plant (so only the PV plant had to be optimized), the methodology could be applied for the optimization of an integrated CSP + PV plant during the design phase.

  17. Issues in Moroccan Higher Education

    Directory of Open Access Journals (Sweden)

    Mohammed Lazrak

    2017-06-01

    Full Text Available Historically, education has always been the springboard for socio-economic development of nations. Undoubtedly, education proved to be the catalyst of change and the front wagon that drives with it all the other wagons pertaining to other dynamic sectors. In effect, the role of education can be seen to provide pupils with the curriculum and hidden curriculum skills alike; teaching skills that will prepare them physically, mentally and socially for the world of work in later life. In Morocco, the country spends over 26% of its Gross Domestic Product (GDP on education. Unfortunately, though this number is important, Moroccan education (primary, secondary and higher education alike still suffers from the mismatch between the state expenditures on education and the general product in reality. In this article, an attempt is made to touch on some relevant issues pertaining to higher education with special reference to Morocco. First, it provides some tentative definitions, mission and functions of university and higher education. Second, it gives a historical sketch of the major reforms that took place in Morocco as well as the major changes pertaining to these reforms respectively. Third, it provides a general overview of the history of higher education in Morocco, it also tackles an issue related to governance in higher education which is cost sharing. Fourth, it delves into the history of English Language Teaching (ELT, lists some characteristics of the English Departments in Morocco. Fifth, it discusses the issue of private vs. public higher education. Last, but not least, it tackles the issue of Brain Drain.

  18. A course of higher mathematics

    CERN Document Server

    Smirnov, Vladimir Ivanovich; Lohwater, A J

    1964-01-01

    A Course of Higher Mathematics, I: Elementary Calculus is a five-volume course of higher mathematics used by mathematicians, physicists, and engineers in the U.S.S.R. This volume deals with calculus and principles of mathematical analysis including topics on functions of single and multiple variables. The functional relationships, theory of limits, and the concept of differentiation, whether as theories and applications, are discussed. This book also examines the applications of differential calculus to geometry. For example, the equations to determine the differential of arc or the parameter

  19. ERP for Romanian Higher Education

    Directory of Open Access Journals (Sweden)

    2007-01-01

    Full Text Available Also most of the big ERP providers provide solutions for higher education, including SAP AG, Oracle, JD Eduards, Peoplesoft, universities preferr other specialized applications which better fit their specific needs. This paper presents the advantages of an integrated solution for higher education and analyzes the solutions offered for this sector by the Romanian ERP market. The conlusion is more like an invitation to discussion about possible solutions to the present Romanian university situation: low budgets, changing regulations, isolated, self-developed applications.

  20. Mergers in European Higher Education

    DEFF Research Database (Denmark)

    Rocha, Vera; Teixeira, Pedro N.; Biscaia, Ricardo

    2018-01-01

    In recent years, mergers have been widely used in higher education (HE) to achieve a variety of purposes, ranging from problems of institutional fragmentation to the lack of financial and academic viability, and low institutional efficiency and quality. However, despite a large stream of HE...... literature addressing those issues, there has been little attention to the link between funding-related problems and merger processes. Moreover, there is very little comparative research among different higher education systems experiencing those processes. In this paper, we map and characterize the recent...

  1. Optimal Admission to Higher Education

    DEFF Research Database (Denmark)

    Albæk, Karsten

    This paper constructs higher education admission rules that maximise graduation rates and thus increase the skill level of the work force. An application shows that students with a low level in mathematics in secondary school ought to find it easier to be admitted to an economics programme than...... to law or psychology programmes, even though economics is the most difficult programme from which to graduate without a strong background in mathematics. Indirect gains from optimal admission include the potential of making whole cohorts of students more able to graduate with a higher education degree....

  2. A Paraconsistent Higher Order Logic

    DEFF Research Database (Denmark)

    Villadsen, Jørgen

    2004-01-01

    of paraconsistent logics in knowledge-based systems, logical semantics of natural language, etc. Higher order logics have the advantages of being expressive and with several automated theorem provers available. Also the type system can be helpful. We present a concise description of a paraconsistent higher order...... of the logic is examined by a case study in the domain of medicine. Thus we try to build a bridge between the HOL and MVL communities. A sequent calculus is proposed based on recent work by Muskens. Many non-classical logics are, at the propositional level, funny toys which work quite good, but when one wants...

  3. Radiosensitivity in plants

    International Nuclear Information System (INIS)

    Nauman, A.F.

    1979-01-01

    The report presents a compilation of available data on the sensitivity of plants to ionizing radiation, and provides basic information on methods of determining such sensitivities, or of estimating radiosensitivities by calcuation of the nuclear factors upon which they depend. The scope of the data presented here is necessarily limited to the most generally useful radiobiological end points and to the most commonly-used types of radiation. Many of the factors which influence radiosensitivity, particularly nuclear factors, will be discussed. Emphasis will be upon whole-plant studies done at Brookhaven National Laboratory by A.H. Sparrow and his associates, since these studies are the source of most of the available radiosensitivity data and of all the sensitivity predictions listed here. Data presented here include summaries of experimentally-determined radiosensitivities at various end points for both herbaceous and woody higher plants, and for a few species of ferns and lower plants. The algae and fungi have not been considered here due to space limitations

  4. Radiosensitivity in plants

    Energy Technology Data Exchange (ETDEWEB)

    Nauman, A F

    1979-01-01

    The report presents a compilation of available data on the sensitivity of plants to ionizing radiation, and provides basic information on methods of determining such sensitivities, or of estimating radiosensitivities by calcuation of the nuclear factors upon which they depend. The scope of the data presented here is necessarily limited to the most generally useful radiobiological end points and to the most commonly-used types of radiation. Many of the factors which influence radiosensitivity, particularly nuclear factors, will be discussed. Emphasis will be upon whole-plant studies done at Brookhaven National Laboratory by A.H. Sparrow and his associates, since these studies are the source of most of the available radiosensitivity data and of all the sensitivity predictions listed here. Data presented here include summaries of experimentally-determined radiosensitivities at various end points for both herbaceous and woody higher plants, and for a few species of ferns and lower plants. The algae and fungi have not been considered here due to space limitations.

  5. Higher Education's Coming Leadership Crisis

    Science.gov (United States)

    Appadurai, Arjun

    2009-01-01

    The full impact of the current recession on American higher education remains uncertain, but drops in applications, faculty autonomy and job security, frozen salaries and hiring processes, and scaling back of new facilities and programs are already being seen. American colleges face tough times ahead for teaching, research, and capital projects…

  6. Assessing Cyberbullying in Higher Education

    Science.gov (United States)

    Kamali, Ali

    2015-01-01

    This project aims to expose information educators to various aspects of cyberbullying for the purpose of policy development in an environment of higher education. The preponderance of nation-wide research on cyberbullying is concentrated on adolescents; such efforts in college campuses are limited to individual endeavors. Cyberbullying research on…

  7. Nonlocal higher order evolution equations

    KAUST Repository

    Rossi, Julio D.; Schö nlieb, Carola-Bibiane

    2010-01-01

    In this article, we study the asymptotic behaviour of solutions to the nonlocal operator ut(x, t)1/4(-1)n-1 (J*Id -1)n (u(x, t)), x ∈ ℝN, which is the nonlocal analogous to the higher order local evolution equation vt(-1)n-1(Δ)nv. We prove

  8. Higher Education and European Regionalism.

    Science.gov (United States)

    Paterson, Lindsay

    2001-01-01

    Speculates about the relationship between two fundamental social changes occurring in Europe: the development of a mass higher education system and the slow decay of the old states that were inherited from the 19th century, eroded from below by various movements for national and regional autonomy, and eroded from above by the growing power and…

  9. Information technologies in higher education

    OpenAIRE

    Dimitrova, F.

    2012-01-01

    The article deals with the use of Information Technologies in modern Higher Education. The author describes possible means of its application in the process of teaching English for students of Language Departments. Diverse online resources, advanced methods, progressive approaches are integral parts of modern teaching learning process in contemporary world and essential in strengthening language awareness and professional skills.

  10. OSHA: Implications for Higher Education.

    Science.gov (United States)

    National Association of College and University Business Officers, Washington, DC.

    Presented in this document are several articles concerning recommendations about the Occupational Safety and Health Act of 1970 (OSHA) and its implications for higher education. It is time for an educated look at facilities and programs and the beginning of plans which, in the long run, will bring colleges and universities into compliance with…

  11. Project Management in Higher Education

    Science.gov (United States)

    Alpert, Shannon Atkinson

    2011-01-01

    This study identified factors that influenced the use of project management in higher education research projects. Using a qualitative grounded theory approach that included in-depth interviews with assistant professors, the researcher examined how these individuals were using project management processes and tools and factors that enabled,…

  12. Wave equations in higher dimensions

    CERN Document Server

    Dong, Shi-Hai

    2011-01-01

    Higher dimensional theories have attracted much attention because they make it possible to reduce much of physics in a concise, elegant fashion that unifies the two great theories of the 20th century: Quantum Theory and Relativity. This book provides an elementary description of quantum wave equations in higher dimensions at an advanced level so as to put all current mathematical and physical concepts and techniques at the reader’s disposal. A comprehensive description of quantum wave equations in higher dimensions and their broad range of applications in quantum mechanics is provided, which complements the traditional coverage found in the existing quantum mechanics textbooks and gives scientists a fresh outlook on quantum systems in all branches of physics. In Parts I and II the basic properties of the SO(n) group are reviewed and basic theories and techniques related to wave equations in higher dimensions are introduced. Parts III and IV cover important quantum systems in the framework of non-relativisti...

  13. The Opening of Higher Education

    Science.gov (United States)

    Matkin, Gary W.

    2012-01-01

    In a 1974 report presented to the Organisation for Economic Co-operation and Development (OECD), Martin Trow laid out a framework for understanding large-scale, worldwide changes in higher education. Trow's essay also pointed to the problems that "arise out of the transition from one phase to another in a broad pattern of development of higher…

  14. Higher Education Evaluation in Germany

    Science.gov (United States)

    Schmidt, Bernhard; von Hippel, Aiga; Tippelt, Rudolf

    2010-01-01

    Quality assurance in the area of higher education has become a central issue among both politicians and scientists. University evaluations which refer to both research and teaching are an important element of quality assurance. The present contribution starts out by determining the different components of quality at universities according to…

  15. Disability Studies in Higher Education

    Science.gov (United States)

    Taylor, Steven J.

    2011-01-01

    As a topic of study, disability is not new at institutions of higher education. Psychological and intellectual disabilities have been of interest in psychiatry and psychology at least since the late 1800s and early 1900s. The post-World War II era, in particular, witnessed the rapid expansion of academic programs in special education, vocational…

  16. Optimal admission to higher education

    DEFF Research Database (Denmark)

    Albæk, Karsten

    2016-01-01

    that documents the relevance of theory and illustrates how to apply optimal admission procedures. Indirect gains from optimal admission procedures include the potential for increasing entire cohorts of students' probability of graduating with a higher education degree, thereby increasing the skill level...

  17. Topologically Massive Higher Spin Gravity

    NARCIS (Netherlands)

    Bagchi, A.; Lal, S.; Saha, A.; Sahoo, B.

    2011-01-01

    We look at the generalisation of topologically massive gravity (TMG) to higher spins, specifically spin-3. We find a special "chiral" point for the spin-three, analogous to the spin-two example, which actually coincides with the usual spin-two chiral point. But in contrast to usual TMG, there is the

  18. Stakeholder Relationships in Higher Education

    Science.gov (United States)

    Kettunen, Juha

    2015-01-01

    The purpose of this study is to develop a stakeholder map to describe the most important stakeholders and the process of stakeholder relationships in higher education. According to the perspective of the balanced scorecard, the classification of stakeholders integrates stakeholders into strategic management. Stakeholder maps are essential in…

  19. Today's Higher Education IT Workforce

    Science.gov (United States)

    Bichsel, Jacqueline

    2014-01-01

    The professionals making up the current higher education IT workforce have been asked to adjust to a culture of increased IT consumerization, more sourcing options, broader interest in IT's transformative potential, and decreased resources. Disruptions that include the bring-your-own-everything era, cloud computing, new management practices,…

  20. Mitigating Higher Ed Cyber Attacks

    Science.gov (United States)

    Rogers, Gary; Ashford, Tina

    2015-01-01

    In this presentation we will discuss the many and varied cyber attacks that have recently occurred in the higher ed community. We will discuss the perpetrators, the victims, the impact and how these institutions have evolved to meet this threat. Mitigation techniques and defense strategies will be covered as will a discussion of effective security…

  1. Danish aid to higher education

    DEFF Research Database (Denmark)

    Adriansen, Hanne Kirstine

    2016-01-01

    This piece comments on the role of higher education and universities in achieving the goals of Agenda 2030. It also asks if global academic collaboration is a new form of colonization or if researchers from the North can assist in decolonising the academy....

  2. Higher Ambitions Summit. Rapporteur Report

    Science.gov (United States)

    Nash, Ian

    2014-01-01

    The Sutton Trust and Pearson two-day summit on higher ambitions in apprenticeships and vocational education drew more than 120 leaders in education, training and employment, policy makers, academics, and researchers to London. Delegates heard from political leaders stressing the importance they attach to high-quality apprenticeships. Presentations…

  3. Higher Education Profiles & Trends 2013

    Science.gov (United States)

    Tennessee Higher Education Commission, 2013

    2013-01-01

    The statute [T.C.A. Section 49-7-202(c)(7)] requires the Tennessee Higher Education Commission to prepare a biennial report for the governor and the general assembly, "commenting upon major developments, trends, new policies, budgets and financial considerations which in the judgment of the commission will be useful to the governor and to the…

  4. Higher holonomies: comparing two constructions

    DEFF Research Database (Denmark)

    Schaetz, Florian; Arias Abad, Camilo

    2015-01-01

    , there are the higher holonomies associated with flat superconnections as studied by Igusa [7], Block–Smith [3] and Arias Abad–Schätz [1]. We first explain how by truncating the latter construction one obtains examples of the former. Then we prove that the two-dimensional holonomies provided by the two approaches...

  5. Catholic Higher Education as Mission

    Science.gov (United States)

    Lowery, Daniel

    2012-01-01

    This article uses the work of Anthony J. Gittins to reframe our understanding of Catholic higher education as mission. The broad adoption of this framework would require a common intellectual foundation, the possibility of which is dismissed by many. An accessible ontology is implied, however, in the existential analysis and theology of Karl…

  6. Sustainability: Higher Education's New Fundamentalism

    Science.gov (United States)

    Peterson, Rachelle; Wood, Peter W.

    2015-01-01

    "Sustainability" is a key idea on college campuses in the United States and the rest of the Western world. To the unsuspecting, sustainability is just a new name for environmentalism. This report is the first in-depth critical study of the sustainability movement in higher education. The focus of this study is on how the sustainability…

  7. Maize yield and quality in response to plant density and application of a novel plant growth regulator

    NARCIS (Netherlands)

    Zhang, Q.; Zhang, L.; Evers, J.B.; Werf, van der W.; Zhang, W.; Duan, L.

    2014-01-01

    Farmers in China have gradually increased plant density in maize to achieve higher yields, but this has increased risk of lodging due to taller and weaker stems at higher plant densities. Plant growth regulators can be used to reduce lodging risk. In this study, for the first time, the performance

  8. Correction: Comparative analysis of fungal genomes reveals different plant cell wall degrading capacity in fungi

    Science.gov (United States)

    2014-01-01

    Abstract The version of this article published in BMC Genomics 2013, 14: 274, contains 9 unpublished genomes (Botryobasidium botryosum, Gymnopus luxurians, Hypholoma sublateritium, Jaapia argillacea, Hebeloma cylindrosporum, Conidiobolus coronatus, Laccaria amethystina, Paxillus involutus, and P. rubicundulus) downloaded from JGI website. In this correction, we removed these genomes after discussion with editors and data producers whom we should have contacted before downloading these genomes. Removing these data did not alter the principle results and conclusions of our original work. The relevant Figures 1, 2, 3, 4 and 6; and Table 1 have been revised. Additional files 1, 3, 4, and 5 were also revised. We would like to apologize for any confusion or inconvenience this may have caused. Background Fungi produce a variety of carbohydrate activity enzymes (CAZymes) for the degradation of plant polysaccharide materials to facilitate infection and/or gain nutrition. Identifying and comparing CAZymes from fungi with different nutritional modes or infection mechanisms may provide information for better understanding of their life styles and infection models. To date, over hundreds of fungal genomes are publicly available. However, a systematic comparative analysis of fungal CAZymes across the entire fungal kingdom has not been reported. Results In this study, we systemically identified glycoside hydrolases (GHs), polysaccharide lyases (PLs), carbohydrate esterases (CEs), and glycosyltransferases (GTs) as well as carbohydrate-binding modules (CBMs) in the predicted proteomes of 94 representative fungi from Ascomycota, Basidiomycota, Chytridiomycota, and Zygomycota. Comparative analysis of these CAZymes that play major roles in plant polysaccharide degradation revealed that fungi exhibit tremendous diversity in the number and variety of CAZymes. Among them, some families of GHs and CEs are the most prevalent CAZymes that are distributed in all of the fungi analyzed

  9. EDITORIAL: Deeper, broader, higher, better?

    Science.gov (United States)

    Dobson, Ken

    1998-07-01

    Honorary Editor The standard of educational achievement in England and Wales is frequently criticized, and it seems to be an axiom of government that schools and teachers need to be shaken up, kept on a tight rein, copiously inspected, shamed and blamed as required: in general, subjected to the good old approach of: ' Find out what Johnny is doing and tell him to stop.' About the only exception to this somewhat severe attitude is at A-level, where the standard is simply golden. Often, comparisons are made between the performance of, say, English children and that of their coevals in other countries, with different customs, systems, aims and languages. But there has been a recent comparison of standards at A-level with a non-A-level system of pre-university education, in an English-speaking country that both sends students to English universities and accepts theirs into its own, and is, indeed, represented in the UK government at well above the level expected from its ethnical weighting in the population. This semi-foreign country is Scotland. The conclusions of the study are interesting. Scotland has had its own educational system, with `traditional breadth', and managed to escape much of the centralized authoritarianism that we have been through south of the border. It is interesting to note that, while for the past dozen years or so the trend in A-level Physics entries has been downwards, there has been an increase in the take-up of Scottish `Highers'. Highers is a one-year course. Is its popularity due to its being easier than A-level? Scottish students keen enough to do more can move on to the Certificate of Sixth Year Studies, and will shortly be able to upgrade a Higher Level into an Advanced Higher Level. A comparability study [ Comparability Study of Scottish Qualifications and GCE Advanced Levels: Report on Physics January 1998 (free from SQA)] was carried out by the Scottish Qualifications Authority (SQA) with the aim (amongst others) of helping

  10. Higher-Order Program Generation

    DEFF Research Database (Denmark)

    Rhiger, Morten

    for OCaml, a dialect of ML, that provides run-time code generation for OCaml programs. We apply these byte-code combinators in semantics-directed compilation for an imperative language and in run-time specialization using type-directed partial evaluation. Finally, we present an approach to compiling goal......This dissertation addresses the challenges of embedding programming languages, specializing generic programs to specific parameters, and generating specialized instances of programs directly as executable code. Our main tools are higher-order programming techniques and automatic program generation....... It is our thesis that they synergize well in the development of customizable software. Recent research on domain-specific languages propose to embed them into existing general-purpose languages. Typed higher-order languages have proven especially useful as meta languages because they provide a rich...

  11. Playful learning in higher education

    DEFF Research Database (Denmark)

    Nørgård, Rikke Toft; Toft-Nielsen, Claus; Whitton, Nicola

    2017-01-01

    in higher education through the metaphor of the ‘magic circle’. This approach stimulates intrinsic motivation and educational drive, creates safe spaces for academic experimentation and exploration, and promotes reflective risk-taking, ideation, and participation in education. We present a model of playful......Increased focus on quantifiable performance and assessment in higher education is creating a learning culture characterised by fear of failing, avoidance of risk, and extrinsic goal-oriented behaviours. In this article, we explore possibilities of a more playful approach to teaching and learning...... learning, drawing on notions of signature pedagogies, field literature, and two qualitative studies on learner conceptions of enjoyment and reasons for disengagement. We highlight the potential of this approach to invite a different mind-set and environment, providing a formative space in which failure...

  12. Higher dimensional loop quantum cosmology

    International Nuclear Information System (INIS)

    Zhang, Xiangdong

    2016-01-01

    Loop quantum cosmology (LQC) is the symmetric sector of loop quantum gravity. In this paper, we generalize the structure of loop quantum cosmology to the theories with arbitrary spacetime dimensions. The isotropic and homogeneous cosmological model in n + 1 dimensions is quantized by the loop quantization method. Interestingly, we find that the underlying quantum theories are divided into two qualitatively different sectors according to spacetime dimensions. The effective Hamiltonian and modified dynamical equations of n + 1 dimensional LQC are obtained. Moreover, our results indicate that the classical big bang singularity is resolved in arbitrary spacetime dimensions by a quantum bounce. We also briefly discuss the similarities and differences between the n + 1 dimensional model and the 3 + 1 dimensional one. Our model serves as a first example of higher dimensional loop quantum cosmology and offers the possibility to investigate quantum gravity effects in higher dimensional cosmology. (orig.)

  13. Charged gravastars in higher dimensions

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, S., E-mail: shnkghosh122@gmail.com [Department of Physics, Indian Institute of Engineering Science and Technology, B. Garden, Howrah 711103, West Bengal (India); Rahaman, F., E-mail: rahaman@associates.iucaa.in [Department of Mathematics, Jadavpur University, Kolkata 700032, West Bengal (India); Guha, B.K., E-mail: bkguhaphys@gmail.com [Department of Physics, Indian Institute of Engineering Science and Technology, B. Garden, Howrah 711103, West Bengal (India); Ray, Saibal, E-mail: saibal@associates.iucaa.in [Department of Physics, Government College of Engineering and Ceramic Technology, 73 A.C.B. Lane, Kolkata 700010, West Bengal (India)

    2017-04-10

    We explore possibility to find out a new model of gravastars in the extended D-dimensional Einstein–Maxwell space–time. The class of solutions as obtained by Mazur and Mottola of a neutral gravastar have been observed as a competent alternative to D-dimensional versions of the Schwarzschild–Tangherlini black hole. The outer region of the charged gravastar model therefore corresponds to a higher dimensional Reissner–Nordström black hole. In connection to this junction conditions, therefore we have formulated mass and the related Equation of State of the gravastar. It has been shown that the model satisfies all the requirements of the physical features. However, overall observational survey of the results also provide probable indication of non-applicability of higher dimensional approach for construction of a gravastar with or without charge from an ordinary 4-dimensional seed as far as physical ground is concerned.

  14. Higher curvature supergravity and cosmology

    Energy Technology Data Exchange (ETDEWEB)

    Ferrara, Sergio [Th-Ph Department, CERN, Geneva (Switzerland); U.C.L.A., Los Angeles, CA (United States); INFN - LNF, Frascati (Italy); Sagnotti, Augusto [Scuola Normale Superiore, Pisa (Italy); INFN, Pisa (Italy)

    2016-04-15

    In this contribution we describe dual higher-derivative formulations of some cosmological models based on supergravity. Work in this direction started with the R + R{sup 2} Starobinsky model, whose supersymmetric extension was derived in the late 80's and was recently revived in view of new CMB data. Models dual to higher-derivative theories are subject to more restrictions than their bosonic counterparts or standard supergravity. The three sections are devoted to a brief description of R + R{sup 2} supergravity, to a scale invariant R{sup 2} supergravity and to theories with a nilpotent curvature, whose duals describe non-linear realizations (in the form of a Volkov-Akulov constrained superfield) coupled to supergravity. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Nonlocal higher order evolution equations

    KAUST Repository

    Rossi, Julio D.

    2010-06-01

    In this article, we study the asymptotic behaviour of solutions to the nonlocal operator ut(x, t)1/4(-1)n-1 (J*Id -1)n (u(x, t)), x ∈ ℝN, which is the nonlocal analogous to the higher order local evolution equation vt(-1)n-1(Δ)nv. We prove that the solutions of the nonlocal problem converge to the solution of the higher order problem with the right-hand side given by powers of the Laplacian when the kernel J is rescaled in an appropriate way. Moreover, we prove that solutions to both equations have the same asymptotic decay rate as t goes to infinity. © 2010 Taylor & Francis.

  16. Academic Freedom in Higher Education

    Directory of Open Access Journals (Sweden)

    Tokay GEDİKOĞLU

    2013-12-01

    Full Text Available In this study, the concept ‘academic freedom’ is discussed, its implications and value for the academics, institutions of higher education, and the society are focused, and a few suggestions for the Turkish higher education are made. Academic freedom is defined as the freedom of the academic staff to look for and to find the truth in their scientific field, to publish the findings, and to teach these findings to their students without any external intervention. The concept has gained a further definition with inclusion of research activities into academic freedom as part of the reform attempts started in the German higher education in the 19th century. Therefore, academic freedom is at the very core of the missions of the institutions of higher education; that is, teaching-learning and research. On the point of academic staff and their academic activities of the academic freedom, the subjects such as the aim of the course, choosing the teaching materials and textbooks, the lecturer, and the criteria for the measurement and evaluation of the course take place. And he point of research covers the aim of the study, academicians can’t be imposed the involve in an academic and artistic studies that conflict their values and beliefs; researchers should comply with codes of ethical principles and practices during the process of researching; and research outputs should be reported accurately and honestly without any misleading manipulation. Academic freedom does not provide any exemption from accountability in academic activities of the faculty, nor does it provide any right to act against the well-being of the society, current laws and regulations, and codes of ethical principles and practices.

  17. Cosmic censorship in higher dimensions

    International Nuclear Information System (INIS)

    Goswami, Rituparno; Joshi, Pankaj S.

    2004-01-01

    We show that the naked singularities arising in dust collapse from smooth initial data (which include those discovered by Eardley and Smarr, Christodoulou, and Newman) are removed when we make a transition to higher dimensional spacetimes. Cosmic censorship is then restored for dust collapse, which will always produce a black hole as the collapse end state for dimensions D≥6, under conditions to be motivated physically such as the smoothness of initial data from which the collapse develops

  18. Higher prices, higher quality? Evidence from German nursing homes.

    Science.gov (United States)

    Herr, Annika; Hottenrott, Hanna

    2016-02-01

    This study investigates the relationship between prices and quality of 7400 German nursing homes. We use a cross section of public quality reports for all German nursing homes, which had been evaluated between 2010 and 2013 by external institutions. Our analysis is based on multivariate regressions in a two stage least squares framework, where we instrument prices to explain their effect on quality controlling for income, nursing home density, demographics, labour market characteristics, and infrastructure at the regional level. Descriptive analysis shows that prices and quality do not only vary across nursing homes, but also across counties and federal states and that quality and prices correlate positively. Second, the econometric analysis, which accounts for the endogenous relation between negotiated price and reported quality, shows that quality indeed positively depends on prices. In addition, more places in nursing homes per people in need are correlated with both lower prices and higher quality. Finally, unobserved factors at the federal state level capture some of the variation of reported quality across nursing homes. Our results suggest that higher prices increase quality. Furthermore, since reported quality and prices vary substantially across federal states, we conclude that the quality and prices of long-term care facilities may well be compared within federal states but not across. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  19. Metodologia de seleção de cepas para produção etodologia da ciclodextrina glicosiltransferase e para purificação da enzima - DOI: 10.4025/actascihealthsci.v29i1.133 Strains selection methodology for cyclodextrin glycosyltransferase production and enzyme purification - DOI: 10.4025/actascihealthsci.v29i1.133

    Directory of Open Access Journals (Sweden)

    Graciette Matioli

    2007-12-01

    Full Text Available As ciclodextrinas (CDs são maltooligossacarídeos, produzidas a partir do amido, pela enzima ciclodextrina glicosiltransferase (CGTase. Esta pesquisa teve por objetivo estabelecer metodologias de seleção de cepas para produção de CGTase e para purificação da enzima. Os microrganismos foram selecionados a partir de 53 análises de solos de cultura de amido, em placas contendo meio de cultivo específico, para seleção de cepas produtoras de CGTase. As enzimas foram obtidas com cultivo destes microrganismos em meio líquido. As atividades enzimáticas das CGTases foram determinadas pelos métodos espectrofotométricos e precipitação com tricloroetileno. A cepa isolada do solo de aveia foi a que apresentou maior atividade [0,1864 mol de -CD (min mL-1]. Esta cepa foi utilizada para a produção da enzima em escala laboratorial e purificação em cromatografia de afinidade bioespecífica. A cepa selecionada nesta pesquisa abre novas perspectivas para produção de enzima e CDs em escala industrial. Palavras-chave: ciclodextrina, glicosiltransferase, CGTase.Cyclodextrins (CDs are maltooligosaccharides produced from starch by cyclodextrin glycosyltransferase (CGTase enzyme. This research aimed at establishing method for strains selection for CGTase production and enzyme purification. The microorganisms were selected from 53 analyses of starch cultures soils on plates containing specific culture medium for strains selection that produce CGTase. The enzymes were obtained by culturing these microorganisms in liquid medium. The enzyme activity was determined with photospectrometric methods and precipitation with trichloroethylene. The strain isolated from oat soil was the one that showed the highest activity [0.1864 µmol of ß-CD (min mL-1]. This strain was used for enzyme production in laboratory scale and purification by biospecific affinity chromatography. The strain selected in this research opens new perspectives for enzymes

  20. Dispatchable Solar Power Plant Project

    Energy Technology Data Exchange (ETDEWEB)

    Price, Henry [Solar Dynamics LLC, Broomfield, CO (United States)

    2018-01-31

    to DSP plants. These results estimate that the cost of the DSP plant is about 10% higher than a similarly-sized and operated frame combustion turbine and slightly cheaper than an aero derivative combustion turbine when APS reference fuel and emissions costs are included. The DSP plant cost is based on a single, first-of-a-kind plant, and it is likely that subsequent plants would be less expensive.

  1. Does chemical aposematic (warning) signaling occur between host plants and their potential parasitic plants?

    Science.gov (United States)

    Lev-Yadun, Simcha

    2013-07-01

    Aposematism (warning) signaling is a common defensive mechanism toward predatory or herbivorous animals, i.e., interactions between different trophic levels. I propose that it should be considered at least as a working hypothesis that chemical aposematism operates between certain host plants and their plant predators, parasitic plants, and that although they are also plants, they belong to a higher trophic level. Specific host plant genotypes emit known repelling chemical signals toward parasitic plants, which reduce the level of, slow the directional parasite growth (attack) toward the signaling hosts, or even cause parasitic plants to grow away from them in response to these chemicals. Chemical host aposematism toward parasitic plants may be a common but overlooked defense from parasitic plants.

  2. Stress tolerant plants

    OpenAIRE

    Rubio, Vicente; Iniesto Sánchez, Elisa; Irigoyen Miguel, María Luisa

    2014-01-01

    [EN] The invention relates to transgenic plants and methods for modulating abscisic acid (ABA) perception and signal transduction in plants. The plants find use in increasing yield in plants, particularly under abiotic stress.

  3. Radioactive properties of medicinal plants

    International Nuclear Information System (INIS)

    Ahmedova, G.A.

    2003-01-01

    Full text: A complicated cycle of various compounds' synthesis is provided by plants in the process of their development. The synthesized compounds are necessary to maintain the life of all living organisms both in water and on the land. Together with the organic compounds all known natural radionuclides are accumulated by the plants. Many plants possess the ability to accumulate some elements, whose concentration in the plants may be much higher than that in the soils and water sources. It is well known that the plants are basic or initial raw materials for producing numerous food products, as well as medicinal preparations. The radionuclides, accumulated in the plants, may pass to the human organism through the products and drugs, and may become a source of internal radiation. Accumulation of the radionuclides in various human organs above the maximal acceptable concentration (MAC) may lead to various pathologic changes. That is why it is a necessary and urgent problem to carry out investigations of the radioactive properties of the plants (i.e. to determine their radioecological cleanliness) before using the medicinal plant for pharmacological purposes. In the present work we investigated the radioactive processes of kinds of medicinal plants by the method of semi-conductor gamma-spectrometry. Measurements of the gamma-spectra of the plants' leach were carried out with the help of a gamma-spectrometer with a Ge(Li) detector accompanied by a 4096-channel analyzer. Responsive volume of the detector was 40 cm 3 , energy resolution with respect to 1333 keV 60 Co line was 3 keV. In the measured spectra we observed clearly photo-peaks belonging to uranium-238 family: 186 keV 226 Ra; 295, 351 keV 214 Pb; 609, 1120, 1764 keV 214 Bi; and those belonging to thorium - 232 family: 339, 911, 968 keV 2 28 Ac; 583, 2614 keV 208 Te; as well as the photo-peak of the natural radionuclide 40 K with the energy 1460 keV. From the proper gamma-lines, observed in the spectra, we

  4. Disruptive technologies in higher education

    Directory of Open Access Journals (Sweden)

    Michael Flavin

    2012-08-01

    Full Text Available This paper analyses the role of “disruptive” innovative technologies in higher education. In this country and elsewhere, Higher Education Institutions (HEIs have invested significant sums in learning technologies, with Virtual Learning Environments (VLEs being more or less universal, but these technologies have not been universally adopted and used by students and staff. Instead, other technologies not owned or controlled by HEIs are widely used to support learning and teaching. According to Christensen's theory of Disruptive Innovation, these disruptive technologies are not designed explicitly to support learning and teaching in higher education, but have educational potential. This study uses Activity Theory and Expansive Learning to analyse data regarding the impact of disruptive technologies. The data were obtained through a questionnaire survey about awareness and use of technologies, and through observation and interviews, exploring participants’ actual practice. The survey answers tended to endorse Disruptive Innovation theory, with participants establishing meanings for technologies through their use of them, rather than in keeping with a designer's intentions. Observation revealed that learners use a narrow range of technologies to support learning, but with a tendency to use resources other than those supplied by their HEIs. Interviews showed that participants use simple and convenient technologies to support their learning and teaching. This study identifies a contradiction between learning technologies made available by HEIs, and technologies used in practice. There is no evidence to suggest that a wide range of technologies is being used to support learning and teaching. Instead, a small range of technologies is being used for a wide range of tasks. Students and lecturers are not dependent on their HEIs to support learning and teaching. Instead, they self-select technologies, with use weighted towards established brands. The

  5. Higher dimensional discrete Cheeger inequalities

    Directory of Open Access Journals (Sweden)

    Anna Gundert

    2015-01-01

    Full Text Available For graphs there exists a strong connection between spectral and combinatorial expansion properties. This is expressed, e.g., by the discrete Cheeger inequality, the lower bound of which states that $\\lambda(G \\leq h(G$, where $\\lambda(G$ is the second smallest eigenvalue of the Laplacian of a graph $G$ and $h(G$ is the Cheeger constant measuring the edge expansion of $G$. We are interested in generalizations of expansion properties to finite simplicial complexes of higher dimension (or uniform hypergraphs. Whereas higher dimensional Laplacians were introduced already in 1945 by Eckmann, the generalization of edge expansion to simplicial complexes is not straightforward. Recently, a topologically motivated notion analogous to edge expansion that is based on $\\mathbb{Z}_2$-cohomology was introduced by Gromov and independently by Linial, Meshulam and Wallach. It is known that for this generalization there is no direct higher dimensional analogue of the lower bound of the Cheeger inequality. A different, combinatorially motivated generalization of the Cheeger constant, denoted by $h(X$, was studied by Parzanchevski, Rosenthal and Tessler. They showed that indeed $\\lambda(X \\leq h(X$, where $\\lambda(X$ is the smallest non-trivial eigenvalue of the ($(k-1$-dimensional upper Laplacian, for the case of $k$-dimensional simplicial complexes $X$ with complete $(k-1$-skeleton. Whether this inequality also holds for $k$-dimensional complexes with non-com\\-plete$(k-1$-skeleton has been an open question.We give two proofs of the inequality for arbitrary complexes. The proofs differ strongly in the methods and structures employed,and each allows for a different kind of additional strengthening of the original result.

  6. Engineering of plants with improved properties as biofuels feedstocks by vessel-specific complementation of xylan biosynthesis mutants

    Directory of Open Access Journals (Sweden)

    Petersen Pia Damm

    2012-11-01

    Full Text Available Abstract Background Cost-efficient generation of second-generation biofuels requires plant biomass that can easily be degraded into sugars and further fermented into fuels. However, lignocellulosic biomass is inherently recalcitrant toward deconstruction technologies due to the abundant lignin and cross-linked hemicelluloses. Furthermore, lignocellulosic biomass has a high content of pentoses, which are more difficult to ferment into fuels than hexoses. Engineered plants with decreased amounts of xylan in their secondary walls have the potential to render plant biomass a more desirable feedstock for biofuel production. Results Xylan is the major non-cellulosic polysaccharide in secondary cell walls, and the xylan deficient irregular xylem (irx mutants irx7, irx8 and irx9 exhibit severe dwarf growth phenotypes. The main reason for the growth phenotype appears to be xylem vessel collapse and the resulting impaired transport of water and nutrients. We developed a xylan-engineering approach to reintroduce xylan biosynthesis specifically into the xylem vessels in the Arabidopsis irx7, irx8 and irx9 mutant backgrounds by driving the expression of the respective glycosyltransferases with the vessel-specific promoters of the VND6 and VND7 transcription factor genes. The growth phenotype, stem breaking strength, and irx morphology was recovered to varying degrees. Some of the plants even exhibited increased stem strength compared to the wild type. We obtained Arabidopsis plants with up to 23% reduction in xylose levels and 18% reduction in lignin content compared to wild-type plants, while exhibiting wild-type growth patterns and morphology, as well as normal xylem vessels. These plants showed a 42% increase in saccharification yield after hot water pretreatment. The VND7 promoter yielded a more complete complementation of the irx phenotype than the VND6 promoter. Conclusions Spatial and temporal deposition of xylan in the secondary cell wall of

  7. Instabilities of higher dimensional compactifications

    International Nuclear Information System (INIS)

    Accetta, F.S.

    1987-02-01

    Various schemes for cosmological compactification of higher dimensional theories are considered. Possible instabilities which drive the ground state with static internal space to de Sitter-like expansion of all dimensions are discussed. These instabilities are due to semiclassical barrier penetration and classical thermal fluctuations. For the case of the ten dimensional Chapline-Manton action, it is possible to avoid such difficulties by balancing one-loop Casimir corrections against monopole contributions from the field strength H/sub MNP/ and fermionic condensates. 10 refs

  8. Innovations in higher medical education

    Directory of Open Access Journals (Sweden)

    Popkov V.M.

    2014-03-01

    Full Text Available The article is devoted to the innovations in the higher medical education. Particular attention in this sphere is paid to the detailed analysis of the subject as a mechanism of cognition and psycho-emotional aspect. It should be noticed that the development of the university education demands the integration of functional systems to study the general medicine and the art of healing. In conclusion it has been found out that the new methodological approach is necessary to bring the teacher closer to the subject particularly to integrate the relation of the opposites.

  9. A course of higher mathematics

    CERN Document Server

    Smirnov, Vladimir Ivanovich

    1964-01-01

    A Course of Higher Mathematics, Volume II: Advanced Calculus covers the theory of functions of real variable in advanced calculus. This volume is divided into seven chapters and begins with a full discussion of the solution of ordinary differential equations with many applications to the treatment of physical problems. This topic is followed by an account of the properties of multiple integrals and of line integrals, with a valuable section on the theory of measurable sets and of multiple integrals. The subsequent chapters deal with the mathematics necessary to the examination of problems in

  10. Classical higher-order processes

    DEFF Research Database (Denmark)

    Montesi, Fabrizio

    2017-01-01

    Classical Processes (CP) is a calculus where the proof theory of classical linear logic types processes à la Π-calculus, building on a Curry-Howard correspondence between session types and linear propositions. We contribute to this research line by extending CP with process mobility, inspired...... by the Higher-Order Π-calculus. The key to our calculus is that sequents are asymmetric: one side types sessions as in CP and the other types process variables, which can be instantiated with process values. The controlled interaction between the two sides ensures that process variables can be used at will......, but always respecting the linear usage of sessions expected by the environment....

  11. Higher spins and Yangian symmetries

    Energy Technology Data Exchange (ETDEWEB)

    Gaberdiel, Matthias R. [Institut für Theoretische Physik, ETH Zurich, CH-8093 Zurich (Switzerland); Gopakumar, Rajesh [International Centre for Theoretical Sciences-TIFR, Survey No. 151, Shivakote, Hesaraghatta Hobli, Bengaluru North 560 089 (India); Li, Wei [CAS Key Laboratory of Theoretical Physics,Institute of Theoretical Physics, Chinese Academy of Sciences,100190 Beijing (China); Peng, Cheng [Department of Physics, Brown University, 182 Hope Street, Providence, RI 02912 (United States)

    2017-04-26

    The relation between the bosonic higher spin W{sub ∞}[λ] algebra, the affine Yangian of gl{sub 1}, and the SH{sup c} algebra is established in detail. For generic λ we find explicit expressions for the low-lying W{sub ∞}[λ] modes in terms of the affine Yangian generators, and deduce from this the precise identification between λ and the parameters of the affine Yangian. Furthermore, for the free field cases corresponding to λ=0 and λ=1 we give closed-form expressions for the affine Yangian generators in terms of the free fields. Interestingly, the relation between the W{sub ∞} modes and those of the affine Yangian is a non-local one, in general. We also establish the explicit dictionary between the affine Yangian and the SH{sup c} generators. Given that Yangian algebras are the hallmark of integrability, these identifications should pave the way towards uncovering the relation between the integrable and the higher spin symmetries.

  12. Chemical defence and toxins of plants

    OpenAIRE

    Yamane, H.; Konno, K.; Sabelis, M.; Takabayashi, J.; Sassa, T.; Oikawa, H.; Mander, L.; Lui, H.W.

    2010-01-01

    Higher plants protect themselves by producing a variety of secondary metabolites and proteins that are involved in defense against herbivores as well as microbial pathogens. Concerning microbial pathogenesis in plants, in many cases, it is known that phytotoxins that are produced by plant pathogens play an important role in disease development causing chlorosis, necrosis, or wilting. This chapter mainly focuses on the chemical structures, distribution, and biosynthesis of defense-related natu...

  13. CERN: Higher energies at LEP

    International Nuclear Information System (INIS)

    Anon.

    1995-01-01

    This year will be the last that CERN's 27-kilometre LEP electron-positron collider will run routinely at around 45 GeV per beam. In the run, scheduled to begin in May, the four big experiments will top up their harvest so far of over 12 million Z particles for a final polishing of precision Z data. Behind the scenes, LEP is being prepared for higher energy running and a new phase of physics. After a brief technical stop in October, the aim is for a test run of up to 70 GeV per beam before the end of the year. Higher energy demands more radiofrequency power, which will be supplied by superconducting cavities. With this goal in mind, a programme of development work began at CERN over ten years ago, when LEP was still on the drawing board. Initially this effort focused on cavities made from sheet niobium, but later switched to copper covered by a sputtered niobium film, which gives better thermal and r.f. performance (September 1990, page 24). The first industrially-manufactured four-cavity niobium coated module, complete with its cryostat and r.f plumbing, was installed in LEP in 1993. Although it quickly achieved its nominal accelerating gradient of 6 MV/m, its reliability was affected by unforeseen problems in the associated power couplers. This delayed the installation schedule, but after a crash programme of design and modification of the power couplers, together with improvements in actual cavity design and manufacture, module supply and testing has now attained a satisfactory rhythm. Two modules installed in LEP amassed between them over 50 days of continuous running in 1994, and confidence is now high that the emphasis can shift towards integrating the cavities into LEP, rather than running the cavities themselves. During LEP's 1994-5 winter shutdown, modules are being installed at Points 2 and 6. Later, additional cavities will be installed in Points 2, 6 and 8 prior to embarking on the higher energy test run at the end of the year. After

  14. Wuergassen nuclear power plant

    International Nuclear Information System (INIS)

    Anon.

    1989-01-01

    The decision of the Federal Court of Administration concerns an application for immediate decommissioning of a nuclear power plant (Wuergassen reactor): The repeal of the permit granted. The decision dismisses the appeal for non-admission lodged by the plaintiffs against the ruling of the Higher Court of Administration (OVG) of North-Rhine Westphalia of December 19th 1988 (File no. 21 AK 8/88). As to the matter in dispute, the Federal Court of Administration confirms the opinion of the Higher Court of Administration. As to the headnotes, reference can be made to that decision. Federal Court of Administration, decision of April 5th 1989 - 7 B 47.89. Lower instance: OVG NW, Az.: 21 AK 8/88. (orig./RST) [de

  15. Gravitating multidefects from higher dimensions

    CERN Document Server

    Giovannini, Massimo

    2007-01-01

    Warped configurations admitting pairs of gravitating defects are analyzed. After devising a general method for the construction of multidefects, specific examples are presented in the case of higher-dimensional Einstein-Hilbert gravity. The obtained profiles describe diverse physical situations such as (topological) kink-antikink systems, pairs of non-topological solitons and bound configurations of a kink and of a non-topological soliton. In all the mentioned cases the geometry is always well behaved (all relevant curvature invariants are regular) and tends to five-dimensional anti-de Sitter space-time for large asymptotic values of the bulk coordinate. Particular classes of solutions can be generalized to the framework where the gravity part of the action includes, as a correction, the Euler-Gauss-Bonnet combination. After scrutinizing the structure of the zero modes, the obtained results are compared with conventional gravitating configurations containing a single topological defect.

  16. Gravastars with higher dimensional spacetimes

    Science.gov (United States)

    Ghosh, Shounak; Ray, Saibal; Rahaman, Farook; Guha, B. K.

    2018-07-01

    We present a new model of gravastar in the higher dimensional Einsteinian spacetime including Einstein's cosmological constant Λ. Following Mazur and Mottola (2001, 2004) we design the star with three specific regions, as follows: (I) Interior region, (II) Intermediate thin spherical shell and (III) Exterior region. The pressure within the interior region is equal to the negative matter density which provides a repulsive force over the shell. This thin shell is formed by ultra relativistic plasma, where the pressure is directly proportional to the matter-energy density which does counter balance the repulsive force from the interior whereas the exterior region is completely vacuum assumed to be de Sitter spacetime which can be described by the generalized Schwarzschild solution. With this specification we find out a set of exact non-singular and stable solutions of the gravastar which seems physically very interesting and reasonable.

  17. Nonlinearity management in higher dimensions

    International Nuclear Information System (INIS)

    Kevrekidis, P G; Pelinovsky, D E; Stefanov, A

    2006-01-01

    In the present paper, we revisit nonlinearity management of the time-periodic nonlinear Schroedinger equation and the related averaging procedure. By means of rigorous estimates, we show that the averaged nonlinear Schroedinger equation does not blow up in the higher dimensional case so long as the corresponding solution remains smooth. In particular, we show that the H 1 norm remains bounded, in contrast with the usual blow-up mechanism for the focusing Schroedinger equation. This conclusion agrees with earlier works in the case of strong nonlinearity management but contradicts those in the case of weak nonlinearity management. The apparent discrepancy is explained by the divergence of the averaging procedure in the limit of weak nonlinearity management

  18. Library assessment in higher education

    CERN Document Server

    Matthews, Joseph R

    2015-01-01

    Academic libraries are increasingly being asked to demonstrate their value as one of many units on campus, but determining the outcomes of an academic library within the context of its collegiate setting is challenging. This book explains and clarifies the practice of assessment in academic institutions, enabling library managers to better understand and explain the impact of the library on student learning outcomes, teaching effectiveness, and research productivity. Providing essential information for all college and university librarians, this volume discusses and summarizes the outcomes of research that has been conducted to investigate assessment within the context of higher education. This updated second edition incorporates additional research, examines new trends, and covers groundbreaking advances in digital assessment tools as well as the changes in the amount and forms of data utilized in the assessment process. The chapters address assessment from a campus setting and present data that demonstrate...

  19. Bianchi identities in higher dimensions

    International Nuclear Information System (INIS)

    Pravda, V; Pravdova, A; Coley, A; Milson, R

    2004-01-01

    A higher dimensional frame formalism is developed in order to study implications of the Bianchi identities for the Weyl tensor in vacuum spacetimes of the algebraic types III and N in arbitrary dimension n. It follows that the principal null congruence is geodesic and expands isotropically in two dimensions and does not expand in n - 4 spacelike dimensions or does not expand at all. It is shown that the existence of such principal geodesic null congruence in vacuum (together with an additional condition on twist) implies an algebraically special spacetime. We also use the Myers-Perry metric as an explicit example of a vacuum type D spacetime to show that principal geodesic null congruences in vacuum type D spacetimes do not share this property

  20. Nutritional and cultural aspects of plant species selection for a controlled ecological life support system

    Science.gov (United States)

    Hoff, J. E.; Howe, J. M.; Mitchell, C. A.

    1982-01-01

    The feasibility of using higher plants in a controlled ecological life support system is discussed. Aspects of this system considered important in the use of higher plants include: limited energy, space, and mass, and problems relating to cultivation and management of plants, food processing, the psychological impact of vegetarian diets, and plant propagation. A total of 115 higher plant species are compared based on 21 selection criteria.