Relevant bibliographies by topics / Plant cell cycle

Contents

  1. Journal articles
  2. Dissertations / Theses
  3. Books
  4. Book chapters
  5. Conference papers
  6. Reports

Academic literature on the topic 'Plant cell cycle'

Author: Grafiati
Published: 4 June 2021
Last updated: 31 January 2023

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Journal articles on the topic "Plant cell cycle"

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Francis, Dennis, and Nigel G. Halford. "The plant cell cycle." Physiologia Plantarum 93, no. 2 (February 1995): 365–74. http://dx.doi.org/10.1111/j.1399-3054.1995.tb02241.x.

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Francis, Dennis, and Nigel G. Halford. "The plant cell cycle." Physiologia Plantarum 93, no. 2 (February 1995): 365–74. http://dx.doi.org/10.1034/j.1399-3054.1995.930223.x.

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Veylder, Lieven De, Jérôme Joubès, and Dirk Inzé. "Plant cell cycle transitions." Current Opinion in Plant Biology 6, no. 6 (December 2003): 536–43. http://dx.doi.org/10.1016/j.pbi.2003.09.001.

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Huntley, Rachael P., and James AH Murray. "The plant cell cycle." Current Opinion in Plant Biology 2, no. 6 (December 1999): 440–46. http://dx.doi.org/10.1016/s1369-5266(99)00027-8.

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Bryant, J. A., and D. Francis. "The plant cell cycle." Annals of Botany 107, no. 7 (May 2011): 1063. http://dx.doi.org/10.1093/aob/mcr101.

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Chasan, Rebecca. "STARTing the Plant Cell Cycle." Plant Cell 7, no. 1 (January 1995): 1. http://dx.doi.org/10.2307/3869832.

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Chasan, R. "STARTing the Plant Cell Cycle." Plant Cell 7, no. 1 (January 1, 1995): 1–4. http://dx.doi.org/10.1105/tpc.7.1.1.

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Inze, Dirk, Crisanto Gutierrez, and Nam-Hai Chua. "Trends in Plant Cell Cycle Research." Plant Cell 11, no. 6 (June 1999): 991. http://dx.doi.org/10.2307/3870792.

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Scofield, Simon, Angharad Jones, and James A. H. Murray. "The plant cell cycle in context." Journal of Experimental Botany 65, no. 10 (May 26, 2014): 2557–62. http://dx.doi.org/10.1093/jxb/eru188.

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Inzé, Dirk, Crisanto Gutiérrez, and Nam-Hai Chua. "Trends in Plant Cell Cycle Research." Plant Cell 11, no. 6 (June 1999): 991–94. http://dx.doi.org/10.1105/tpc.11.6.1.

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Dissertations / Theses on the topic "Plant cell cycle"

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Jopson, Martin Frederick. "Plant microtubules, their associated proteins and the cell cycle." Thesis, University of East Anglia, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318090.

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Kulaveerasingam, Harikrishna. "A molecular study of dedifferentiation and cell cycle reactivation in mechanically isolated asparagus cells." Thesis, University of Leicester, 1989. http://hdl.handle.net/2381/33631.

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Mechanically isolated cell cultures were chosen as a model system to examine wound-induced dedifferentiation at the molecular level as large quantities of physiologically and morphologically similar G1-arrested mesophyll cells could be obtained. Within 5 days of culture such non-dividing, photosynthetic cells become heterotrophic, and have completed a first nuclear division and cytokinesis. There are few changes in cell morphology during the first 2-3 days in culture. However, during this period there is a massive increase in respiration rate and total RNA synthesis. Following DNA synthesis there is a rapid cell expansion, mitosis and cytokinesis. Steady state transcript populations were monitored through the first 8 days of culture by analysis of the products of in vitro translations on 2-D gels. Large changes in gene expression were evident during the first 3 days in culture with several genes highly up-regulated and others down-regulated. Dedifferentiation can be separated into 3 different phases. Firstly, reactivation of the cell cycle during which there are few cytological or physiological changes but gross changes in the expression of genes possibly associated with wounding or stress. Secondly, DNA synthesis, first mitosis event and phragmoplast formation during which there are minor changes in transcript abundance. Finally a continuation of the cell cycle with little alteration in transcript abundance. Changes in plastid morphology are only apparent after 10-14 days resulting in the formation of proplastid like structures. However, mRNA for both large subunit ribulose bisphosphate carboxylase and small subunit ribulose bisphosphate carboxylase decrease to basal levels within a day of culture and photosynthetic capacity diminishes when the first cell division is evident. Plastid dedifferentiation can therefore be considered separately and proceeds slowly being more or less complete after 2-3 cell divisions. Dedifferentiation is therefore seen to be a complex process which involves the interaction of several factors i.e wounding and hormones and results in temporal changes in transcript abundance, changes in the mode of respiration, morphology and cell proliferation.
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Harper, John D. I. "Genetical and ultrastructural analysis of the Chlamydomonas cell cycle." Thesis, Queen's University Belfast, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.236312.

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Rafiei, Golnaz. "Studies on the role of WEE1 in the plant cell cycle." Thesis, Cardiff University, 2012. http://orca.cf.ac.uk/30683/.

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WEE 1 is a key eukaryotic cell cycle regulator. In plants it has a clear role at the DNA damage/ DNA replication checkpoints. I aimed to discover the functional significance of interactions between WEE1 and other cellular proteins in Arabidopsis thaliana and Nicotiana tabacum. First I examined effects of ectopic expression of Arabidopsis WEE1 (Arath;WEE1) in transgenic tobacco and tobacco WEE1 (Nicta;WEE1) in transgenic Arabidopsis. Western blotting using a plant WEE1 antibody showed that expression of Nicta;WEE1 in Arabidopsis caused increases in total WEE1 protein. The response of primary root length, numbers of lateral roots and primordia, and meristem length to zeocin (a DNA damaging agent) and hydroxyurea, (which perturbs DNA replication), resembled the wee1-1 insertional mutant rather than Arath;WEE1 over-expression. Expression of Arath;WEE1 in tobacco resulted in reduced WEE1 protein but also induced similar phenotypic changes as Nicta;WEE1 expression in Arabidopsis under zeocin and HU stress. I concluded that interactions with cellular proteins in the alien species resulted in down-regulation of WEE1 activity. In a yeast 2-hybrid screen Arath;WEE1 interacted with the glutathione-S-transferase protein, GSTF9. To test the functionality of this interaction I analysised the root and cell cycle phase phenotypes of single mutants: wee1-1 and gstf9 and I generated the double mutant wee1-1;gstf9. I demonstrated that both Arath;WEE1 and GSTF9 have roles in the DNA replication and damage checkpoints, but largely act in different genetic pathways. Arath;WEE1 also interacts with GF14ω, a 14-3-3 protein in a yeast 2-hybrid assay. In other eukaryotes this stabilizes WEE1. I confirmed that over-expression of GFF14ω in transgenic Arabidopsis (GFF14ω OEX) results in a very similar root phenotype to over-expression of Arath;WEE1 as predicted from a stabilization of WEE1. However the GFF14ω OEX phenotype was not abolished in a wee1-1 genetics background.indicating that Arath;WEE1is not required for the action of GF14ω.
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Spadafora, N. D. "Effect of CDC25 and WEE1 on plant cell cycle and morphogenesis." Thesis, University of Worcester, 2010. http://eprints.worc.ac.uk/745/.

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The cell cycle comprises the four phases of, G1, S-phase, G2 and mitosis. Two critical transitions are G1/S and G2/M; the latter is regulated by WEE1 kinase and CDC25 phosphatases. The scope of this thesis was to investigate the regulation of the G2/M transition of the cell cycle by WEE1 and CDC25, and how these genes interface with plant growth regulators in Arabidopsis thaliana. In Arabidopsis roots, the frequency of lateral roots was found to be increased by ectopic expression of Schizosaccharomyces pombe (Sp)cdc25e and reduced by Arath;WEE1 expression. I examined the effect of Arath;WEE1 and Spcdc25 on induction of shoots and roots in Arabidopsis hypocotyls in vitro. Hypocotyl explants from two over-expressing WEE1 lines , three T-DNA insertion lines and two expressing cdc25 (Spcdc25e) lines together with wild type (WT) were cultured on two-way gradients of kinetin (Kin) and naphthyl acetic acid (NAA). Below a threshold concentration of NAA (100 ng ml-1), WEE1 repressed morphogenesis in vitro, whereas at all NAA/Kin combinations Spcdc25 promoted morphogenesis (particularly root formation) over and above that in WT. Loss of function wee1-1 cultures were very similar to WT. Quantitative data indicated a significant increase in the frequency of root formation in Spcdc25e cultures compared with WT particularly at low Kin concentrations, and WEE1oe’s repressive effect was overcome by NAA but not Kin. In conclusion, WEE1 has a repressive effect on morphogenesis in vitro that can be overcome by auxin whereas Spcd25 by-passes a cytokinin requirement for the induction of morphogenesis in vitro. The role of CDC25 and WEE1 in DNA damage responses was also analysed. Two over-expressing Arath;CDC25 lines and T-DNA mutants showed no difference to WT either in standard conditions or zeocin-supplemented treatments. However, root length was longer in Arath;CDC25oe lines treated with hydroxyurea (HU) and lateral root number was increased compared to WT. This suggests a differential response of Arath;CDC25oe in the DNA replication (HU-induced) and DNA damage (zeocin-induced) checkpoints (Chapter 5). Finally the roles of WEE1 and CDC25 in cell cycle regulation were examined using tobacco TBY-2 cell cultures expressing Arath;WEE1, Nicotiana tabacum (Nicta)WEE1 or Arath;CDC25. Whilst Nicta;WEE1 lengthened G2 of the cell cycle, Arath;WEE1 had an unusual effect of shortening G2 phase and Arath;CDC25 had no observable effect (Chapter 6).
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Webb, Penelope 1967. "Effects of yeast cell cycle gene expression in transgenic Nicotiana tabacum." Monash University, Dept. of Biological Sciences, 2001. http://arrow.monash.edu.au/hdl/1959.1/9084.

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Vieira, Paulo. "Cell cycle maneuvering : a strategy taken by plant parasitic nematodes to induce specialized feeding sites in plant roots." Nice, 2012. http://www.theses.fr/2012NICE4114.

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He, Enuo. "Stochastic modelling of the cell cycle." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:04185cde-85af-4e24-8d06-94b865771cf1.

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Precise regulation of cell cycle events by the Cdk-control network is essential for cell proliferation and the perpetuation of life. The unidirectionality of cell cycle progression is governed by several critical irreversible transitions: the G1-to-S transition, the G2-to-M transition, and the M-to-G1 transition. Recent experimental and theoretical evidence has pulled into question the consensus view that irreversible protein degradation causes the irreversibility of those transitions. A new view has started to emerge, which explains the irreversibility of cell cycle transitions as a consequence of systems-level feedback rather than of proteolysis. This thesis applies mathematical modelling approaches to test this proposal for the Mto- G1 transition, which consists of two consecutive irreversible substeps: the metaphase-to-anaphase transition, and mitotic exit. The main objectives of the present work were: (i) to develop deterministic models to identify the essential molecular feedback loops and to examine their roles in the irreversibility of the M-to-G1 transition; (ii) to present a straightforward and reliable workflow to translate deterministic models of reaction networks into stochastic models; (iii) to explore the effects of noise on the cell cycle transitions using stochastic models, and to compare the deterministic and the stochastic approaches. In the first part of this thesis, I constructed a simplified deterministic model of the metaphase-to-anaphase transition, which is mainly regulated by the spindle assembly checkpoint (the SAC). Based on the essential feedback loops causing the bistability of the transition, this deterministic model provides explanations for three open questions regarding the SAC: Why is the SAC not reactivated when the kinetochore tension decreases to zero at anaphase onset? How can a single unattached kinetochore keep the SAC active? How is the synchronized and abrupt destruction of cohesin triggered? This deterministic model was then translated into a stochastic model of the SAC by treating the kinetochore microtubule attachment at prometaphase as a noisy process. The stochastic model was analyzed and simulation results were compared to the experimental data, with the aim of explaining the mitotic timing regulation by the SAC. Our model works remarkably well in qualitatively explaining experimental key findings and also makes testable predictions for different cell lines with very different number of chromosomes. The noise generated from the chemical interactions was found to only perturb the transit timing of the mitotic events, but not their ultimate outcomes: all cells eventually undergo anaphase, however, the time required to satisfy the SAC differs between cells due to stochastic effects. In the second part of the thesis, stochastic models of mitotic exit were created for two model organisms, budding yeast and mammalian cells. I analyzed the role of noise in mitotic exit at both the single-cell and the population level. Stochastic time series simulations of the models are able to explain the phenomenon of reversible mitotic exit, which is observed under specific experimental conditions in both model organisms. In spite of the fact that the detailed molecular networks of mitotic exit are very different in budding yeast and mammalian cells, their dynamic properties are similar. Importantly, bistability of the transitions is successfully captured also in the stochastic models. This work strongly supports the hypothesis that uni-directional cell cycle progression is a consequence of systems-level feedback in the cell cycle control system. Systems-level feedback creates alternative steady states, which allows cells to accomplish irreversible transitions, such as the M-to-G1 transition studied here. We demonstrate that stochastic models can serve as powerful tools to capture and study the heterogeneity of dynamical features among individual cells. In this way, stochastic simulations not only complement the deterministic approach, but also help to obtain a better understanding of mechanistic aspects. We argue that the effects of noise and the potential needs for stochastic simulations should not be overlooked in studying dynamic features of biological systems.
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Fülöp, Katalin. "Analysis of two plant protein complexes associated with transcription and cell cycle progression." Szegedi Tudományegyetem, 2005. http://www.theses.fr/2005PA112194.

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Su, Yingtao. "Function and regulation of myc-family bHLHZip transcription factors during the animal and plant cell cycle /." Uppsala : Dept. of Plant Biology and Forest Genetics, Swedish University of Agricultural Sciences, 2008. http://epsilon.slu.se/200836.pdf.

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Books on the topic "Plant cell cycle"

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D, Inzé, ed. The plant cell cycle. Dordrecht: Kluwer Academic Publishers, 2000.

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Inzé, Dirk, ed. The Plant Cell Cycle. Dordrecht: Springer Netherlands, 2000. http://dx.doi.org/10.1007/978-94-010-0936-2.

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A, Bryant J., Francis D, Society for Experimental Biology (Great Britain), and Symposium on the Cell Division Cycle in Plants (1984 : Cardiff, Wales), eds. The Cell division cycle in plants. Cambridge [Cambridgeshire]: Cambridge University Press, 1985.

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Inz, Dirk, ed. Cell Cycle Control and Plant Development. Oxford, UK: Blackwell Publishing Ltd, 2007. http://dx.doi.org/10.1002/9780470988923.

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Ormrod, J. C., and D. Francis, eds. Molecular and Cell Biology of the Plant Cell Cycle. Dordrecht: Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-011-1789-0.

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D, Inzé, ed. The cell cycle control and plant development. Oxford, UK: Blackwell Pub., 2007.

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M. C. M. de Gunst. A random model for plant cell population growth. [Amsterdam, the Netherlands]: Centrum voor Wiskunde en Informatica, 1989.

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A, Bryant J., and Chiatante Donato, eds. Plant cell proliferation and its regulation in growth and development. Chichester: Wiley, 1998.

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Kouwets, Frans. The cell cycle in multinucleate coccoid green algae: Ultrastructure & systematics. Leiden: Rijksherbarium/Hortus Botanicus, 1994.

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1960-, Ormrod J. C., and Francis D, eds. Molecular and cell biology of the plant cell cycle: Proceedings of a meeting held at Lancaster University, 9-10 April 1992. Dordrecht: Kluwer Academic, 1993.

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Book chapters on the topic "Plant cell cycle"

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Inze, Dirk G. "The Plant Cell Cycle." In Plant Biotechnology 2002 and Beyond, 28–29. Dordrecht: Springer Netherlands, 2003. http://dx.doi.org/10.1007/978-94-017-2679-5_5.

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Chaubet-Gigot, Nicole. "Plant A-type cyclins." In The Plant Cell Cycle, 115–31. Dordrecht: Springer Netherlands, 2000. http://dx.doi.org/10.1007/978-94-010-0936-2_10.

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Baskin, Tobias I. "On the constancy of cell division rate in the root meristem." In The Plant Cell Cycle, 1–10. Dordrecht: Springer Netherlands, 2000. http://dx.doi.org/10.1007/978-94-010-0936-2_1.

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Ito, Masaki. "Factors controlling cyclin B expression." In The Plant Cell Cycle, 133–46. Dordrecht: Springer Netherlands, 2000. http://dx.doi.org/10.1007/978-94-010-0936-2_11.

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Vantard, Marylin, Rachel Cowling, and Catherine Delichère. "Cell cycle regulation of the microtubular cytoskeleton." In The Plant Cell Cycle, 147–59. Dordrecht: Springer Netherlands, 2000. http://dx.doi.org/10.1007/978-94-010-0936-2_12.

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Bögre, László, Irute Meskiene, Erwin Heberle-Bors, and Heribert Hirt. "Stressing the role of MAP kinases in mitogenic stimulation." In The Plant Cell Cycle, 161–74. Dordrecht: Springer Netherlands, 2000. http://dx.doi.org/10.1007/978-94-010-0936-2_13.

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Nacry, Philippe, Ulrike Mayer, and Gerd Jürgens. "Genetic dissection of cytokinesis." In The Plant Cell Cycle, 175–89. Dordrecht: Springer Netherlands, 2000. http://dx.doi.org/10.1007/978-94-010-0936-2_14.

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Joubès, Jérôme, and Christian Chevalier. "Endoreduplication in higher plants." In The Plant Cell Cycle, 191–201. Dordrecht: Springer Netherlands, 2000. http://dx.doi.org/10.1007/978-94-010-0936-2_15.

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Goverse, Aska, Janice de Almeida Engler, John Verhees, Sander van der Krol, Johannes Helder, and Godelieve Gheysen. "Cell cycle activation by plant parasitic nematodes." In The Plant Cell Cycle, 203–17. Dordrecht: Springer Netherlands, 2000. http://dx.doi.org/10.1007/978-94-010-0936-2_16.

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Gutierrez, Crisanto. "Geminiviruses and the plant cell cycle." In The Plant Cell Cycle, 219–28. Dordrecht: Springer Netherlands, 2000. http://dx.doi.org/10.1007/978-94-010-0936-2_17.

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Conference papers on the topic "Plant cell cycle"

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Rokni, Masoud. "Technoeconomy of Different Solid Oxide Fuel Cell Based Hybrid Cycles." In ASME 2014 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/imece2014-36858.

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Gas turbine, steam turbine and heat engine (Stirling engine) is used as bottoming cycle for a solid oxide fuel cell plant to compare different plants efficiencies, CO2 emissions and plants cost in terms of $/kW. Each plant is then integrated with biomass gasification and finally six plants configurations are compared with each other. Technoeconomy is used when calculating the cost if the plants. It is found that when a solid oxide fuel cell plant is combined with a gas turbine cycle then the plant efficiency will be the highest one while if a biomass gasification plant is integrated with these hybrid cycles then integrated biomass gasification with solid oxide fuel cell and steam cycle will have the highest plant efficiency. The cost of solid oxide fuel cell with steam plant is found to be the lowest one with a value of about 1030$/kW.
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Chakraborty, Promita, Brygg Ullmer, John Larkin, and Sonja Wiley-Patton. "Architecture of a tangible interface for modeling plant cell cycle." In the 15th ACM Mardi Gras conference. New York, New York, USA: ACM Press, 2008. http://dx.doi.org/10.1145/1341811.1341836.

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Bevc, Frank P., Wayne L. Lundberg, and Dennis M. Bachovchin. "Solid Oxide Fuel Cell Combined Cycles." In ASME 1996 International Gas Turbine and Aeroengine Congress and Exhibition. American Society of Mechanical Engineers, 1996. http://dx.doi.org/10.1115/96-gt-447.

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The integration of the solid oxide fuel cell (SOFC) and combustion turbine technologies can result in combined-cycle power plants, fueled with natural gas. that have high efficiencies and clean gaseous emissions. Results of a study are presented in which conceptual designs were developed for three power plants based upon such an integration, and ranging in rating from 3 to 10 MW net ac. The plant cycles are described, and characteristics of key components are summarized. In addition, plant design-point efficiency estimates are presented, as well as values of other plant performance parameters.
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Spallina, Vincenzo, Matteo C. Romano, Stefano Campanari, and Giovanni Lozza. "A SOFC-Based Integrated Gasification Fuel Cell Cycle With CO2 Capture." In ASME Turbo Expo 2010: Power for Land, Sea, and Air. ASMEDC, 2010. http://dx.doi.org/10.1115/gt2010-22814.

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Application of Solid Oxide Fuel Cells (SOFC) in gasification-based power plants would represent a turning point in the power generation sector, allowing to considerably increase the electric efficiency of coal-fired power stations. Pollutant emissions would also be significantly reduced in Integrated Gasification Fuel Cell cycles (IGFC) considering the much lower emissions of conventional pollutants (NOx, CO, SOx, particulate matter) typical of fuel cell-based systems. In addition, SOFC-based IGFCs appear particularly suited to applications in power plants with CO2 capture. This is evident by considering that SOFCs operate as air separators and partly oxidized fuel exiting the fuel cell does not contain nitrogen from air, like in conventional oxy-fuel processes. The aim of the present paper is the thermodynamic analysis of a SOFC-based IGFC with CO2 capture. In the assessed plant, syngas produced in a high efficiency Shell gasifier is used in SOFC modules after heat recovery and cleaning. Anode exhausts, still containing combustible species, are burned with oxygen produced in the air separation unit, also used to generate the oxygen needed in the gasifier; the product gas is cooled down in a heat recovery steam generator before water condensation and CO2 compression. The plant layout is carefully designed to best exploit heat generated in all the processes and, apart from the fuel cell, exotic components, far from industrial state-of-the-art, are not included. Detailed energy and mass balances are presented for a better comprehension of the obtained results.
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Onda, Kazuo, Takuya Taniuchi, Daisuke Sunakawa, Mitsuyuki Nagahama, Takuto Araki, and Toru Kato. "Cycle Analysis of Low and High H2 Utilization SOFC/Gas Turbine Combined Cycle for CO2 Recovery." In ASME 2006 4th International Conference on Fuel Cell Science, Engineering and Technology. ASMEDC, 2006. http://dx.doi.org/10.1115/fuelcell2006-97061.

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A major factor in global warming is CO2 emission from thermal power plants, which burn fossil fuels. One technology proposed to prevent global warming is CO2 recovery from combustion flue gas and the sequestration of CO2 underground or near the ocean bed. Solid oxide fuel cell (SOFC) can produce highly concentrated CO2, because the reformed fuel gas reacts with oxygen electrochemically without being mixed with air in the SOFC. We therefore propose to operate multi-staged SOFCs with high utilization of reformed fuel to obtain highly concentrated CO2. In this study, we estimated the performance of multi-staged SOFCs considering H2 diffusion and the combined cycle efficiency of a multistage SOFC / gas turbine / CO2 recovery power plant. The power generation efficiency of our CO2 recovery combined cycle is 68.5%, whereas the efficiency of a conventional SOFC/GT cycle with the CO2 recovery amine process is 57.8%.
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Bronicki, Lucien, Carl N. Nett, and Josh Nordquist. "Electricity Generation From Fuel Cell Waste Heat Using an Organic Rankine Cycle." In ASME 2014 12th International Conference on Fuel Cell Science, Engineering and Technology collocated with the ASME 2014 8th International Conference on Energy Sustainability. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/fuelcell2014-6595.

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Fuel cells produce exhaust waste heat that can be harnessed to either meet local heating needs or produce additional electricity via an appropriately chosen bottoming cycle. Power production can often be more economically attractive than heating due to the much higher value of electricity than heat on an equivalent energy basis, especially given fuel cell incentives and subsidies that are based on the net electrical output of the (combined cycle) fuel cell power plant. In this paper we review the application of the Organic Rankin Cycle (ORC) for power production from fuel cell waste heat, with emphasis on the resulting improvements in overall power plant power output, efficiency, economics (e.g., cents/kWh maintenance costs), and emissions levels (e.g., lb/MWh emissions). We also highlight a much less obvious advantage of ORC bottoming of fuel cells; namely, its ability to partially compensate for fuel cell stack degradation over time, and corresponding potential to extend the time required between fuel cell stack overhauls. We will also review the relative difficulty of several well established commercial applications of the ORC for power production from waste heat — such as power production from gas turbine exhaust, etc. — in comparison to fuel cell applications. We conclude that not only is the ORC ideal for fuel cell bottoming, but also that fuel cells are a nearly ideal commercial application area for the ORC. In closing, we summarize a recently completed project believed to be the world’s first commercial application of ORC technology to a fuel cell power plant. This project was completed in less than a year after its initiation, and utilizes a single ORC in conjunction with five fuel cells, all located within a fuel cell park that produces nearly 15 MW of electricity.
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Romano, Matteo C., Stefano Campanari, Vincenzo Spallina, and Giovanni Lozza. "SOFC-Based Hybrid Cycle Integrated With a Coal Gasification Plant." In ASME Turbo Expo 2009: Power for Land, Sea, and Air. ASMEDC, 2009. http://dx.doi.org/10.1115/gt2009-59551.

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Application of large scale high temperature fuel cells on syngas fuel produced from coal would be a turning point in the power generation sector, dramatically improving the efficiency and the environmental performance of coal-fired power plants. The purpose of this study is the assessment of a system constituted by a SOFC-based hybrid cycle integrated with a coal gasification process. In this system, syngas produced in a high efficiency, dry feed, oxygen blown, entrained flow Shell gasifier is cooled, depurated from particulate and sulfur compounds and reheated; the clean syngas feeds a pressurized SOFC together with high pressure air generated by the compressor of a gas turbine. After combustion of unconverted syngas, fuel cell exhausts are expanded and cooled, providing heat to a bottoming steam cycle for an efficient energy recovery. A high integration between gasification and power islands is necessary in order to obtain an elevated efficiency: the heat recovery system from syngas cooling is carefully arranged to provide thermal power for clean syngas reheating, air preheating and steam generation. The paper presents a preliminary analysis of literature results and a discussion of the thermodynamic implications arising from the use of different primary fuels in a fuel cell-gas turbine cycle. Then the work presents a detailed thermodynamic analysis of the proposed IGFC layout, assessing the effect of SOFC operating pressure on power balance and net plant efficiency. A sensitivity analysis on the variation of fuel and air utilization in the fuel cell is also performed. Results show that the present innovative SOFC-based power system may achieve an efficiency gain of 7–11 percentage points, with respect to an advanced IGCC based on state of the art technology.
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Huh, Kwanghak, Parsa Mirmobin, and Shamim Imani. "Installation and Performance Analysis of 125 kW Organic Rankine Cycle for Stationary Fuel Cell Power Plant." In ASME Turbo Expo 2016: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/gt2016-56448.

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Installation and performance analysis of Thermapower™ 125MT Organic Rankine Cycle (ORC) System for recovery of waste heat from an existing Molten Carbonate Fuel Cell (MCFC) plant are presented. Over the last three years, about 100 MWe of new FC stationary power plants are in operation in Korea and more FC stationary power plants are on order and planned. The success of these fuel cell plants is their capability to supply both electricity and heat to customers. In order to promote renewable energy in Korea, the Korean Government is enforcing large power plants to supply electricity generated by renewable energy. The Korea Power Exchange (KPX) buys fuel cell generated electricity as renewable energy with higher price than other fossil fuel power plants [1]. Most of these FC plants supply electricity to power companies with their full capability, however valuable heat is wasted due to the limited demand, especially in summer season and off working hours or lack of heat pipe infrastructures. Due to the recent decrease in electricity price for renewable energy in Korea, the need for efficient utilization of waste heat is ever more demanding. In this study, 125 kWe ORC system is installed to 11.2 MWe FC power plant to demonstrate cost saving benefits. This FC Power plant has 4 units of 2.8 MWe fuel cell in operation and has capacity of producing 6.0 ton/h of 167°C steam. In order to install an ORC system to existing FC plant, their Balance of Plant (BoP) has to be modified since only excess steam is allow to be utilized by the ORC system, after supplying steam to their prime customer. Furthermore, site has distinctly hot and cold seasons, thus affecting condensing conditions and therefore ORC performance. Design considerations to accommodate varying ambient conditions as well as steam flow rate variation are presented and discussed.
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Pass, Rebecca Z., and Chris F. Edwards. "Exergy Analysis of a Solid-Oxide Fuel Cell, Gas Turbine, Steam Turbine Triple-Cycle Power Plant." In ASME 2012 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/imece2012-89609.

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In an effort to make higher efficiency power systems, several joint fuel cell / combustion-based cycles have been proposed and modeled. Mitsubishi Heavy Industries has recently built such a system with a solid-oxide fuel cell gas turbine plant, and is now working on a variant that includes a bottoming steam cycle. They report their double and triple cycles have LHV efficiencies greater than 52% and 70%, respectively. In order to provide insight into the thermodynamics behind such efficiencies, this study attempts to reverse engineer the Mitsubishi Heavy Industries system from publicly available data. The information learned provides the starting point for a computer model of the triple cycle. An exergy analysis is used to compare the triple cycle to its constituent sub-cycles, in particular the natural gas combined cycle. This analysis provides insights into the benefits of integrating the fuel cell and gas turbine architectures in a manner that improves the overall system performance to previously unseen efficiencies.
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Campanari, Stefano, and Ennio Macchi. "Comparative Analysis of Hybrid Cycles Based on Molten Carbonate and Solid Oxide Fuel Cells." In ASME Turbo Expo 2001: Power for Land, Sea, and Air. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/2001-gt-0383.

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High temperature fuel cells are experiencing an increasing amount of attention thanks to the successful operation of prototype plants, including a multi-MW Molten Carbonate Fuel Cell (MCFC) demonstration plant and a hybrid Solid Oxide Fuel Cell (SOFC) gas turbine power plant. Both MCFCs and SOFCs are currently considered attractive for the integration with gas turbines in more complex “hybrid” plants, with projected performances that largely exceed combined cycles efficiencies even at a small-scale size and with an extremely low environmental impact. This paper compares the performances of MCFC and SOFC hybrid cycles. The comparison shows some advantages for the SOFC hybrid cycle in terms of plant simplicity and moderately higher efficiency.
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Reports on the topic "Plant cell cycle"

1

Weil, Clifford F., Anne B. Britt, and Avraham Levy. Nonhomologous DNA End-Joining in Plants: Genes and Mechanisms. United States Department of Agriculture, July 2001. http://dx.doi.org/10.32747/2001.7585194.bard.

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Repair of DNA breaks is an essential function in plant cells as well as a crucial step in addition of modified DNA to plant cells. In addition, our inability to introduce modified DNA to its appropriate locus in the plant genome remains an important hurdle in genetically engineering crop species.We have taken a combined forward and reverse genetics approach to examining DNA double strand break repair in plants, focusing primarily on nonhomologous DNA end-joining. The forward approach utilizes a gamma-plantlet assay (miniature plants that are metabolically active but do not undergo cell division, due to cell cycle arrest) and has resulted in identification of five Arabidopsis mutants, including a new one defective in the homolog of the yeast RAD10 gene. The reverse genetics approach has identified knockouts of the Arabidopsis homologs for Ku80, DNA ligase 4 and Rad54 (one gene in what proves to be a gene family involved in DNA repair as well as chromatin remodeling and gene silencing)). All these mutants have phenotypic defects in DNA repair but are otherwise healthy and fertile. Additional PCR based screens are in progress to find knockouts of Ku70, Rad50, and Mre11, among others. Two DNA end-joining assays have been developed to further our screens and our ability to test candidate genes. One of these involves recovering linearized plasmids that have been added to and then rejoined in plant cells; plasmids are either recovered directly or transformed into E. coli and recovered. The products recovered from various mutant lines are then compared. The other assay involves using plant transposon excision to create DNA breaks in yeast cells and then uses the yeast cell as a system to examine those genes involved in the repair and to screen plant genes that might be involved as well. This award supported three graduate students, one in Israel and two in the U.S., as well as a technician in the U.S., and is ultimately expected to result directly in five publications and one Masters thesis.
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Levy, Avraham A., and Virginia Walbot. Regulation of Transposable Element Activities during Plant Development. United States Department of Agriculture, August 1992. http://dx.doi.org/10.32747/1992.7568091.bard.

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We have studied the regulation of the maize Ac and MuDR transposable elements activities during plant development. Ac was studied in an heterologous system (transgenic tobacco plants and cell suspensions) while MuDR was studied in the native maize background. The focus of this study was on the transcriptional regulation of Ac and MuDR. For Ac, the major achievements were to show that 1-It is autoregulated in a way that the Ac-encoded transposase can repress the activity of its own promoter; 2-It is expressed at low basal level in all the plant organs that were studied, and its activity is stronger in dividing tissues -- a behaviour reminiscent of housekeeping genes; 3- the activity of Ac promoter is cell cycle regulated -- induced at early S-phase and increasing until mitosis; 4- host factor binding sites were identified at both extremities of Ac and may be important for transposition. For MuDR, It was shown that it encodes two genes, mudrA and mudrB, convergently transcribed from near-identical promoters in the terminal inverted repeats. Distinct 5' start sites, alternative splicing, production of antisense RNA and tissue specificity were all shown to be involved in the regulation of MuDR.
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Eshed-Williams, Leor, and Daniel Zilberman. Genetic and cellular networks regulating cell fate at the shoot apical meristem. United States Department of Agriculture, January 2014. http://dx.doi.org/10.32747/2014.7699862.bard.

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The shoot apical meristem establishes plant architecture by continuously producing new lateral organs such as leaves, axillary meristems and flowers throughout the plant life cycle. This unique capacity is achieved by a group of self-renewing pluripotent stem cells that give rise to founder cells, which can differentiate into multiple cell and tissue types in response to environmental and developmental cues. Cell fate specification at the shoot apical meristem is programmed primarily by transcription factors acting in a complex gene regulatory network. In this project we proposed to provide significant understanding of meristem maintenance and cell fate specification by studying four transcription factors acting at the meristem. Our original aim was to identify the direct target genes of WUS, STM, KNAT6 and CNA transcription factor in a genome wide scale and the manner by which they regulate their targets. Our goal was to integrate this data into a regulatory model of cell fate specification in the SAM and to identify key genes within the model for further study. We have generated transgenic plants carrying the four TF with two different tags and preformed chromatin Immunoprecipitation (ChIP) assay to identify the TF direct target genes. Due to unforeseen obstacles we have been delayed in achieving this aim but hope to accomplish it soon. Using the GR inducible system, genetic approach and transcriptome analysis [mRNA-seq] we provided a new look at meristem activity and its regulation of morphogenesis and phyllotaxy and propose a coherent framework for the role of many factors acting in meristem development and maintenance. We provided evidence for 3 different mechanisms for the regulation of WUS expression, DNA methylation, a second receptor pathway - the ERECTA receptor and the CNA TF that negatively regulates WUS expression in its own domain, the Organizing Center. We found that once the WUS expression level surpasses a certain threshold it alters cell identity at the periphery of the inflorescence meristem from floral meristem to carpel fate [FM]. When WUS expression highly elevated in the FM, the meristem turn into indeterminate. We showed that WUS activate cytokinine, inhibit auxin response and represses the genes required for root identity fate and that gradual increase in WUCHEL activity leads to gradual meristem enlargement that affect phyllotaxis. We also propose a model in which the direction of WUS domain expansion laterally or upward affects meristem structure differently. We preformed mRNA-seq on meristems with different size and structure followed by k-means clustering and identified groups of genes that are expressed in specific domains at the meristem. We will integrate this data with the ChIP-seq of the 4 TF to add another layer to the genetic network regulating meristem activity.
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Ohad, Nir, and Robert Fischer. Regulation of plant development by polycomb group proteins. United States Department of Agriculture, January 2008. http://dx.doi.org/10.32747/2008.7695858.bard.

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Our genetic and molecular studies have indicated that FIE a WD-repeat Polycomb group (PcG) protein takes part in multi-component protein complexes. We have shown that FIE PcG protein represses inappropriate programs of development during the reproductive and vegetative phases of the Arabidopsis life cycle. Moreover, we have shown that FIE represses the expression of key regulatory genes that promote flowering (AG and LFY), embryogenesis (LEC1), and shoot formation (KNAT1). These results suggest that the FIE PcG protein participates in the formation of distinct PcG complexes that repress inappropriate gene expression at different stages of plant development. PcG complexes modulate chromatin compactness by modifying histones and thereby regulate gene expression and imprinting. The main goals of our original project were to elucidate the biological functions of PcG proteins, and to understand the molecular mechanisms used by FIE PcG complexes to repress the expression of its gene targets. Our results show that the PcG complex acts within the central cell of the female gametophyte to maintain silencing of MEA paternal allele. Further more we uncovered a novel example of self-imprinting mechanism by the PgG complex. Based on results obtained in the cures of our research program we extended our proposed goals and elucidated the role of DME in regulating plant gene imprinting. We discovered that in addition to MEA,DME also imprints two other genes, FWA and FIS2. Activation of FWA and FIS2 coincides with a reduction in 5-methylcytosine in their respective promoters. Since endosperm is a terminally differentiated tissue, the methylation status in the FWA and FIS2 promoters does not need to be reestablished in the following generation. We proposed a “One-Way Control” model to highlight differences between plant and animal genomic imprinting. Thus we conclude that DEMETER is a master regulator of plant gene imprinting. Future studies of DME function will elucidate its role in processes and disease where DNA methylation has a key regulatory role both in plants and animals. Such information will provide valuable insight into developing novel strategies to control and improve agricultural traits and overcome particular human diseases.
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Chamovitz, A. Daniel, and Georg Jander. Genetic and biochemical analysis of glucosinolate breakdown: The effects of indole-3-carbinol on plant physiology and development. United States Department of Agriculture, January 2012. http://dx.doi.org/10.32747/2012.7597917.bard.

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Genetic and biochemical analysis of glucosinolate breakdown: The effects of indole-3-carbinol on plant physiology and development Glucosinolates are a class of defense-related secondary metabolites found in all crucifers, including important oilseed and vegetable crops in the Brassica genus and the well-studied model plant Arabidopsis thaliana. Upon tissue damage, such as that provided by insect feeding, glucosinolates are subjected to catalysis and spontaneous degradation to form a variety of breakdown products. These breakdown products typically have a deterrent effect on generalist herbivores. Glucosinolate breakdown products also contribute to the anti-carcinogenic effects of eating cabbage, broccoli and related cruciferous vegetables. Indole-3-carbinol, a breakdown product of indol-3-ylmethylglucosinolate, forms conjugates with several other plant metabolites. Although some indole-3-carbinol conjugates have known functions in defense against herbivores and pathogens, most play as yet unidentified roles in plant metabolism, and possibly also plant development. At the outset, our proposal had three main hypotheses: (1) There is a specific detoxification pathway for indole-3-carbinol; (2) Metabolites derived from indole-3-carbinol are phloem-mobile and serve as signaling molecules; and (3) Indole-3-carbinol affects plant cell cycle and cell-differentiation pathways. The experiments were designed to enable us to elucidate how indole-3-carbinol and related metabolites affect plants and their interactions with herbivorous insects. We discovered that indole-3- carbinol rapidly and reversibly inhibits root elongation in a dose-dependent manner, and that this inhibition is accompanied by a loss of auxin activity in the root meristem. A direct interaction between indole-3-carbinol and the auxin perception machinery was suggested, as application of indole-3-carbinol rescued auxin-induced root phenotypes. In vitro and yeast-based protein interaction studies showed that indole-3-carbinol perturbs the auxin-dependent interaction of TIR1 with Aux/IAA proteins, supporting the notion that indole-3-carbinol acts as an auxin antagonist. Furthermore, transcript profiling experiments revealed the influence of indole-3-carbinol on auxin signaling in root tips, and indole-3-carbinol also affected auxin transporters. Brief treatment with indole-3-carbinol led to a reduction in the amount of PIN1 and to mislocalization of PIN2. The results indicate that chemicals induced by herbivory, such as indole-3-carbinol, function not only to repel herbivores, but also as signaling molecules that directly compete with auxin to fine tune plant growth and development, which implies transport of indole-3- carbinol that we are as yet unsuccessful in detecting. Our results indicate that plant defensive metabolites also have secondary functions in regulating aspects of plant metabolism, thereby providing diversity in defense-related plant signaling pathways. Such diversity of of signaling by defensive metabolites would be beneficial for the plant, as herbivores and pathogens would be less likely to mount effective countermeasures. We propose that growth arrest can be mediated directly by the herbivory-induced chemicals, in our case, indole-3-carbinol. Thus, glucosinolate breakdown to I3C following herbivory would have two outcomes: (1) Indole-3-carbinaol would inhibit the herbivore, while (2) at the same time inducing growth arrest within the plant. Thus, our results indicate that I3C is a defensive phytohormone that modulates auxin signaling, leading to growth arrest.
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Ohad, Nir, and Robert Fischer. Regulation of Fertilization-Independent Endosperm Development by Polycomb Proteins. United States Department of Agriculture, January 2004. http://dx.doi.org/10.32747/2004.7695869.bard.

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Arabidopsis mutants that we have isolated, encode for fertilization-independent endosperm (fie), fertilization-independent seed2 (fis2) and medea (mea) genes, act in the female gametophyte and allow endosperm to develop without fertilization when mutated. We cloned the FIE and MEA genes and showed that they encode WD and SET domain polycomb (Pc G) proteins, respectively. Homologous proteins of FIE and MEA in other organisms are known to regulate gene transcription by modulating chromatin structure. Based on our results, we proposed a model whereby both FIE and MEA interact to suppress transcription of regulatory genes. These genes are transcribed only at proper developmental stages, as in the central cell of the female gametophyte after fertilization, thus activating endosperm development. To test our model, the following questions were addressed: What is the Composition and Function of the Polycomb Complex? Molecular, biochemical, genetic and genomic approaches were offered to identify members of the complex, analyze their interactions, and understand their function. What is the Temporal and Spatial Pattern of Polycomb Proteins Accumulation? The use of transgenic plants expressing tagged FIE and MEA polypeptides as well as specific antibodies were proposed to localize the endogenous polycomb complex. How is Polycomb Protein Activity Controlled? To understand the molecular mechanism controlling the accumulation of FIE protein, transgenic plants as well as molecular approaches were proposed to determine whether FIE is regulated at the translational or posttranslational levels. The objectives of our research program have been accomplished and the results obtained exceeded our expectation. Our results reveal that fie and mea mutations cause parent-of-origin effects on seed development by distinct mechanisms (Publication 1). Moreover our data show that FIE has additional functions besides controlling the development of the female gametophyte. Using transgenic lines in which FIE was not expressed or the protein level was reduced during different developmental stages enabled us for the first time to explore FIE function during sporophyte development (Publication 2 and 3). Our results are consistent with the hypothesis that FIE, a single copy gene in the Arabidopsis genome, represses multiple developmental pathways (i.e., endosperm, embryogenesis, shot formation and flowering). Furthermore, we identified FIE target genes, including key transcription factors known to promote flowering (AG and LFY) as well as shoot and leaf formation (KNAT1) (Publication 2 and 3), thus demonstrating that in plants, as in mammals and insects, PcG proteins control expression of homeobox genes. Using the Yeast two hybrid system and pull-down assays we demonstrated that FIE protein interact with MEA via the N-terminal region (Publication 1). Moreover, CURLY LEAF protein, an additional member of the SET domain family interacts with FIE as well. The overlapping expression patterns of FIE, with ether MEA or CLF and their common mutant phenotypes, demonstrate the versatility of FIE function. FIE association with different SET domain polycomb proteins, results in differential regulation of gene expression throughout the plant life cycle (Publication 3). In vitro interaction assays we have recently performed demonstrated that FIE interacts with the cell cycle regulatory component Retinobalsoma protein (pRb) (Publication 4). These results illuminate the potential mechanism by which FIE may restrain embryo sac central cell division, at least partly, through interaction with, and suppression of pRb-regulated genes. The results of this program generated new information about the initiation of reproductive development and expanded our understanding of how PcG proteins regulate developmental programs along the plant life cycle. The tools and information obtained in this program will lead to novel strategies which will allow to mange crop plants and to increase crop production.
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Gafni, Yedidya, and Vitaly Citovsky. Molecular interactions of TYLCV capsid protein during assembly of viral particles. United States Department of Agriculture, April 2007. http://dx.doi.org/10.32747/2007.7587233.bard.

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Tomato yellow leaf curl geminivirus (TYLCV) is a major pathogen of cultivated tomato, causing up to 100% crop loss in many parts of the world. The present proposal, a continuation of a BARD-funded project, expanded our understanding of the molecular mechanisms by which CP molecules, as well as its pre-coat partner V2, interact with each other (CP), with the viral genome, and with cellular proteins during assembly and movement of the infectious virions. Specifically, two major objectives were proposed: I. To study in detail the molecular interactions between CP molecules and between CP and ssDNA leading to assembly of infectious TYLCV virions. II. To study the roles of host cell factors in TYLCV assembly. Our research toward these goals has produced the following major achievements: • Characterization of the CP nuclear shuttling interactor, karyopherin alpha 1, its pattern of expression and the putative involvement of auxin in regulation of its expression. (#1 in our list of publication, Mizrachy, Dabush et al. 2004). • Identify a single amino acid in the capsid protein’s sequence that is critical for normal virus life-cycle. (#2 in our list of publications, Yaakov, Levy et al. in preparation). • Development of monoclonal antibodies with high specificity to the capsid protein of TYLCV. (#3 in our list of publications, Solmensky, Zrachya et al. in press). • Generation of Tomato plants resistant to TYLCV by expressing transgene coding for siRNA targeted at the TYLCV CP. (#4 in our list of publications, Zrachya, Kumar et al. in press). •These research findings provided significant insights into (i) the molecular interactions of TYLCV capsid protein with the host cell nuclear shuttling receptor, and (ii) the mechanism by which TYLCV V2 is involved in the silencing of PTGS and contributes to the virus pathogenicity effect. Furthermore, the obtained knowledge helped us to develop specific strategies to attenuate TYLCV infection, for example, by blocking viral entry into and/or exit out of the host cell nucleus via siRNA as we showed in our publication recently (# 4 in our list of publications). Finally, in addition to the study of TYLCV nuclear import and export, our research contributed to our understanding of general mechanisms for nucleocytoplasmic shuttling of proteins and nucleic acids in plant cells. Also integration for stable transformation of ssDNA mediated by our model pathogen Agrobacterium tumefaciens led to identification of plant specific proteins involved.
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Dickman, Martin B., and Oded Yarden. Characterization of the chorismate mutase effector (SsCm1) from Sclerotinia sclerotiorum. United States Department of Agriculture, January 2015. http://dx.doi.org/10.32747/2015.7600027.bard.

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Sclerotinia sclerotiorum is a filamentous fungus (mold) that causes plant disease. It has an extremely wide range of hosts (>400 species) and causes considerable damage (annual multimillion dollar losses) in economically important crops. It has proven difficult to control (culturally or chemically) and host resistance to this fungus has generally been inadequate. It is believed that this fungus occurs in almost every country. Virulence of this aggressive pathogen is bolstered by a wide array of plant cell wall degrading enzymes and various compounds (secondary metabolites) produced by the fungus. It is well established that plant pathogenic fungi secrete proteins and small molecules that interact with host cells and play a critical role in disease development. Such secreted proteins have been collectively designated as “effectors”. Plant resistance against some pathogens can be mediated by recognition of such effectors. Alternatively, effectors can interfere with plant defense. Some such effectors are recognized by the host plant and can culminate in a programmed cell death (PCD) resistant response. During the course of this study, we analyzed an effector in Sclerotiniasclerotiorum. This specific effector, SsCM1 is the protein chorismatemutase, which is an enzyme involved in a pathway which is important in the production of important amino acids, such a Tryptophan. We have characterized the Sclerotiniaeffector, SsCM1, and have shown that inactivation of Sscm1 does not affect fungal vegetative growth, development or production of oxalic acid (one of this fungus’ secondary metabolites associated with disease) production. However, yhis does result in reduced fungal virulence. We show that, unexpectedly, the SsCM1 protein translocates to the host chloroplast, and demonstrated that this process is required for full fungal virulence. We have also determined that the fungal SsCM1 protein can interact with similar proteins produced by the host. In addition, we have shown that the fungal SsCM1 is able to suppress at least some of the effects imposed by reactive oxygen species which are produced as a defense mechanism by the host. Last, but not least, the results of our studies have provided evidence contradicting the current dogma on at least some of the mechanist aspects of how this pathogen infects the host. Contrary to previousons, indicating that this pathogen kills its host by use of metabolites and enzymes that degrade the host tissue (a process called necrotrophy), we now know that at least in the early phases of infection, the fungus interacts with live host tissue (a phenomenon known as biotrophy). Taken together, the results of our studies provide novel insights concerning the mechanistic aspects of Sclerotinia-host interactions. We hope this information will be used to interfere with the disease cycle in a manner that will protect plants from this devastating fungus.
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Grafi, Gideon, and Brian Larkins. Endoreduplication in Maize Endosperm: An Approach for Increasing Crop Productivity. United States Department of Agriculture, September 2000. http://dx.doi.org/10.32747/2000.7575285.bard.

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The focus of this research project is to investigate the role of endoreduplication in maize endosperm development and the extent to which this process contributes to high levels of starch and storage protein synthesis. Although endoreduplication has been widely observed in many cells and tissues, especially those with high levels of metabolic activity, the molecular mechanisms through which the cell cycle is altered to produce consecutive cycles of S-phase without an intervening M-phase are unknown. Our previous research has shown that changes in the expression of several cell cycle regulatory genes coincide with the onset of endoreduplication. During this process, there is a sharp reduction in the activity of the mitotic cyclin-dependent kinase (CDK) and activation of the S-phase CDK. It appears the M-phase CDK is stable, but its activity is blocked by a proteinaceous inhibitor. Coincidentally, the S-phase checkpoint protein, retinoblastoma (ZmRb), becomes phosphorylated, presumably releasing an E2F-type transcriptional regulator which promotes the expression of genes responsible for DNA synthesis. To investigate the role of these cell cycle proteins in endoreduplication, we have created transgenic maize plants that express various genes in an endosperm-specific manner using a storage protein (g-zein) promoter. During the first year of the grant, we constructed point mutations of the maize M-phase kinase, p34cdc2. One alteration replaced aspartic acid at position 146 with asparagine (p3630-CdcD146N), while another changed threonine 161 to alanine (p3630-CdcT161A). These mutations abolish the activity of the CDK. We hypothesized that expression of the mutant forms of p34cdc2 in endoreduplicating endosperm, compared to a control p34cdc2, would lead to extra cycles of DNA synthesis. We also fused the gene encoding the regulatory subunit of the M- phase kinase, cyclin B, under the g-zein promoter. Normally, cyclin B is expected to be destroyed prior to the onset of endoreduplication. By producing high levels of this protein in developing endosperm, we hypothesized that the M-phase would be extended, potentially reducing the number of cycles of endoreduplication. Finally, we genetically engineered the wheat dwarf virus RepA protein for endosperm-specific expression. RepA binds to the maize retinoblastoma protein and presumably releases E2F-like transcription factors that activate DNA synthesis. We anticipated that inactivation of ZmRb by RepA would lead to additional cycles of DNA synthesis.
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Brown Horowitz, Sigal, Eric L. Davis, and Axel Elling. Dissecting interactions between root-knot nematode effectors and lipid signaling involved in plant defense. United States Department of Agriculture, January 2014. http://dx.doi.org/10.32747/2014.7598167.bard.

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Root-knot nematodes, Meloidogynespp., are extremely destructive pathogens with a cosmopolitan distribution and a host range that affects most crops. Safety and environmental concerns related to the toxicity of nematicides along with a lack of natural resistance sources threaten most crops in Israel and the U.S. This emphasizes the need to identify genes and signal mechanisms that could provide novel nematode control tactics and resistance breeding targets. The sedentary root-knot nematode (RKN) Meloidogynespp. secrete effectors in a spatial and temporal manner to interfere with and mimic multiple physiological and morphological mechanisms, leading to modifications and reprogramming of the host cells' functions, resulted in construction and maintenance of nematodes' feeding sites. For successful parasitism, many effectors act as immunomodulators, aimed to manipulate and suppress immune defense signaling triggered upon nematode invasion. Plant development and defense rely mainly on hormone regulation. Herein, a metabolomic profiling of oxylipins and hormones composition of tomato roots were performed using LC-MS/MS, indicating a fluctuation in oxylipins profile in a compatible interaction. Moreover, further attention was given to uncover the implication of WRKYs transcription factors in regulating nematode development. In addition, in order to identify genes that might interact with the lipidomic defense pathway induced by oxylipins, a RNAseq was performed by exposing M. javanicasecond-stage juveniles to tomato protoplast, 9-HOT and 13-KOD oxylipins. This transcriptome generated a total of 4682 differentially expressed genes (DEGs). Being interested in effectors, we seek for DEGs carrying a predicted secretion signal peptide. Among the DEGs including signal peptide, several had homology with known effectors in other nematode species, other unknown potentially secreted proteins may have a role as root-knot nematodes' effectors which might interact with lipid signaling. The molecular interaction of LOX proteins with the Cyst nematode effectors illustrate the nematode strategy in manipulating plant lipid signals. The function of several other effectors in manipulating plant defense signals, as well as lipids signals, weakening cell walls, attenuating feeding site function and development are still being studied in depth for several novel effectors. As direct outcome of this project, the accumulating findings will be utilized to improve our understanding of the mechanisms governing critical life-cycle phases of the parasitic M. incognita RKN, thereby facilitating design of effective controls based on perturbation of nematode behavior—without producing harmful side effects. The knowledge from this study will promote genome editing strategies aimed at developing nematode resistance in tomato and other nematode-susceptible crop species in Israel and the United States.
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