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Chilufya, Jedaidah Y. "Anandamide-Mediated Growth Changes in Physcomitrella patens." Digital Commons @ East Tennessee State University, 2016. https://dc.etsu.edu/etd/3162.
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Anandamide (NAE 20:4) or arachidonlyethanolamine (AEA) is the most widely studied N-acylethanolamine (NAE) because it mediates several physiological functions in mammals. In vascular plants, 12-18C NAEs inhibit growth in an abscisic acid (ABA)-dependent and -independent manner. Anandamide, which is unique to bryophyte Physcomitrella patens, inhibited gametophyte growth and reduced chlorophyll content when applied exogenously. It is hypothesized that anandamide mediates its responses through morphological and cellular changes. Following growth inhibition by short-term anandamide-treatment, microscopic analyses revealed relocated chloroplasts and depolymerized F-actin in protonemal tips. Long-term treatment showed partially bleached gametophyte cells with degraded and browning chloroplasts. These anandamide-mediated responses have physiological implications as AEA may function as a signal for gametophytes to activate secondary dormancy as seen with ABA. Future studies will investigate the role of AEA in mediating stress responses and possible interaction with ABA.
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Madrid, Eric. "Female gametophyte development and evolution in Piperales." Connect to online resource, 2008. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3337127.
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Roberts, Michael Richard. "Controlling transpositon in the male gametophyte of transgenic plants." Thesis, University of Leicester, 1992. http://hdl.handle.net/2381/35341.
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Investigations were carried out to determine the feasibility of a transposon tagging experiment in flax, Linum usitatissimum. The excision of the maize transposable element Activator (Ac) from the genome of transgenic flax callus was demonstrated, whilst a Dissociation element (Ds) was found to be stable. However, reintegration of excised Ac elements was not detected, and this barrier to gene tagging led to an examination of procedures which might improve the general applicability of transposon tagging. A recombinant Ac transposase gene was constructed in order to achieve a high germinal transposition frequency in transgenic plants; this feature is an essential component of an efficient transposon tagging strategy. The Ac construct was produced by fusing the promoter of an anther-specific gene to the transposase coding region. The anther-specific gene, APG, was cloned from Arabidopsis thaliana, following the identification of four putative microspore-specific mRNAs from Brassica napus. Of these mRNAs, one, termed 13, was analysed in detail and found to encode a novel oleosin protein, and was apparently confined to developing pollen. The I3 cDNA was used as a molecular probe to clone the APG gene, which encodes a proline-rich protein of unknown function. A small gene family encoding proteins with high sequence similarity to the APG protein was identified in B. napus via the isolation of three cDNAs termed CEX1, CEX2 and CEX6. Promoter fragments of the APG gene were demonstrated to drive expression of a ?-glucuronidase reporter gene in the male gametophyte, tapetum, stomium and anther wall of Nicotiana tabacum and Arahidopsis during the microspore development stage of gametogenesis. The restriction of transposition to these cells would permit the production of a seed population containing a wide range of unique transposon inserts which would be stable in during vegetative growth. Such applications of the APG/Ac fusion are discussed.
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McClelland, D. J. "Genetical studies of gametophyte development in the moss Physcomitrella patens." Thesis, University of Leeds, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233202.
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Montardy-Pausader, Josette. "Cytomorphogenese du gametophyte d'une fougere intertropicale anemia phyllitidis (l. ) sw." Paris 6, 1987. http://www.theses.fr/1987PA066536.
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Examen des processus meretiques mis en jeu et caracteristiques infrastructurales des cellules intervenant successivement au cours de l'edification du prothalle cordiforme. On montre que le developpement du prothalle presente un stade biserie caracteristique de l'ontogenese du gametophyte qui conduit a l'initiation laterale d'un meristeme marginal pluricellulaire
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Ku, Chuan-Chih. "TCP6, a regulator in Arabidopsis gametophyte development and DNA damage response." Thesis, University of Edinburgh, 2014. http://hdl.handle.net/1842/17892.
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Plants have developed intricate mechanisms to control growth in response to a variety of environmental cues, to compensate its immobility and to survive in both normal and adverse conditions. The TCP proteins are a family of plant-specific, basic helix-loop-helix (bHLH) transcription factors that involve in different aspects in plant growth and developmental control. The Arabidopsis TCP20 has been shown to involve in coordinating cell growth and proliferation, and in growth arrest in response to DNA double-stranded breaks (DSB). In this thesis, the main interest is to examine the function of Arabidopsis TCP6, which shares the highest homology with TCP20, and like TCP20, contains a putative ATM phosphorylation motif that suggests potential involvement in the ATM/ATR-mediated DSB responses. Expressional analysis including transcript measurement and reporter gene tagging demonstrated that TCP6 is expressed in flowers, in particular in the first mitotic event of pollen and ovule/embryo sac development, indicating that TCP6 potentially involves in regulating the mitotic cell cycle during gametophyte development. Yet no gametophytic or fertility-affecting mutant phenotype was observed in the tcp6 single and tcp6/tcp20 double mutants, which may be due to high functional redundancy. The tcp6/tcp20 double mutant seedlings exhibited significantly higher growth performances in true leaf growth compared to wild type when treated with gamma radiation, implying that both functional TCP6 and TCP20 are involved in response to gamma radiation-generated DSBs. The work of this thesis provides the first expressional and functional characterizations of TCP6, with the results suggesting that TCP6 and other class I TCPs play a role in regulating growth under both normal and stress conditions.
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Wang, Dongfang, Changqing Zhang, David Hearn, Il-Ho Kang, Jayson Punwani, Megan Skaggs, Gary Drews, Karen Schumaker, and Ramin Yadegari. "Identification of transcription-factor genes expressed in the Arabidopsis female gametophyte." BioMed Central, 2010. http://hdl.handle.net/10150/610082.
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BACKGROUND:In flowering plants, the female gametophyte is typically a seven-celled structure with four cell types: the egg cell, the central cell, the synergid cells, and the antipodal cells. These cells perform essential functions required for double fertilization and early seed development. Differentiation of these distinct cell types likely involves coordinated changes in gene expression regulated by transcription factors. Therefore, understanding female gametophyte cell differentiation and function will require dissection of the gene regulatory networks operating in each of the cell types. These efforts have been hampered because few transcription factor genes expressed in the female gametophyte have been identified. To identify such genes, we undertook a large-scale differential expression screen followed by promoter-fusion analysis to detect transcription-factor genes transcribed in the Arabidopsis female gametophyte.RESULTS:Using quantitative reverse-transcriptase PCR, we analyzed 1,482 Arabidopsis transcription-factor genes and identified 26 genes exhibiting reduced mRNA levels in determinate infertile 1 mutant ovaries, which lack female gametophytes, relative to ovaries containing female gametophytes. Spatial patterns of gene transcription within the mature female gametophyte were identified for 17 transcription-factor genes using promoter-fusion analysis. Of these, ten genes were predominantly expressed in a single cell type of the female gametophyte including the egg cell, central cell and the antipodal cells whereas the remaining seven genes were expressed in two or more cell types. After fertilization, 12 genes were transcriptionally active in the developing embryo and/or endosperm.CONCLUSIONS:We have shown that our quantitative reverse-transcriptase PCR differential-expression screen is sufficiently sensitive to detect transcription-factor genes transcribed in the female gametophyte. Most of the genes identified in this study have not been reported previously as being expressed in the female gametophyte. Therefore, they might represent novel regulators and provide entry points for reverse genetic and molecular approaches to uncover the gene regulatory networks underlying female gametophyte development.
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Srilunchang, Kanok-orn. "Molecular characterization and identification of genes involved in maize female gametophyte development." kostenfrei, 2009. http://www.opus-bayern.de/uni-regensburg/volltexte/2009/1366/.
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Yao, Haiqin. "Regulation of gametophyte-to-sporophyte transitions during the file cycle of Ectocarpus." Electronic Thesis or Diss., Sorbonne université, 2019. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2019SORUS424.pdf.
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La plupart des organismes eucaryotes se reproduisent sexuellement et ont des cycles de vie qui impliquent une alternance entre les phases haploïde et diploïde en raison de deux processus fondamentaux : la division cellulaire méiotique (à la transition diploïde-haploïde) et la fusion gamète ou syngamie (transition haploïde-diploïde). Dans les organismes photosynthétiques ayant des cycles de vie haploïde-diploïde, ces alternances sont entre deux générations multicellulaires distinctes : gamétophyte et sporophyte. Comme les générations de gamétophytes et de sporophytes sont construites à partir d'informations provenant d'un génome commun, il s'ensuit que les processus de régulation épigénétique doivent fonctionner à la fois pendant la méiose et pendant la syngamie pour déclencher le déclenchement du programme de développement approprié associé à chaque génération. L'analyse génétique de l'alternance du cycle de vie chez les organismes se répartissant de diverses façons sur les lignées de l'arbre eucaryote permettra d'améliorer notre compréhension au niveau moléculaire. Les connaissances actuelles indiquent que l'alternance du cycle de vie est régulée par des facteurs génétiques (facteurs de transcription du domaine homéodésique) et par des modifications chromatiniennes. La majorité des algues brunes ont un cycle de vie haploïde-diploïde et l'une de ces espèces, l'algue brune filamenteuse Ectocarpus, est utilisée comme système modèle pour étudier la régulation du cycle biologique. L'ectocarpe a un cycle de vie complexe. Les travaux actuels ont montré que l'alternance des générations d'Ectocarpus est contrôlée par deux facteurs de transcription homéodomaine, ORO et SAM, qui régulent l'induction du programme de développement sporophyte. Cependant, l'alternance entre le gamétophyte et le sporophyte peut également être régulée par un facteur sporophyte autonome non cellulaire sécrété dans le milieu de culture par les sporophytes. Ce facteur diffusible provoque une reprogrammation majeure du développement des cellules initiales (méio-spores) du gamétophyte. Il est intéressant de noter que les travaux actuels montrent que le BGC et la SAM peuvent faire partie du réseau de réglementation déclenché par le facteur sporophyte inducteur. Cependant, la nature biochimique de ce facteur n'est pas connue. L'objectif principal de cette thèse était de caractériser le facteur diffusible sporophyte inducteur. Les travaux ont porté sur l'optimisation de la production, du stockage et du dosage biologique du facteur et sur l'obtention d'informations sur sa nature biochimique. L'étude a également examiné la relation entre le facteur sporophyte inducteur et deux régulateurs génétiques, ORO et SAM, pour comprendre la voie de développement déclenchée par le facteur. En plus de ce travail sur l'identité de génération du cycle de vie, la thèse portait sur la caractérisation du mutant sans fondement, qui présente un phénotype similaire à celui du mutant distag et qui est affecté dans la formation de modèles de développement à la fois pendant les générations gamétophytes et sporophytesMost eukaryotic organisms reproduce sexually and have life cycles that involve an alternation between haploid and diploid phases due to two fundamental processes meiotic cell division (at the diploid-to-haploid transition) and gametes fusion or syngamy (haploid-to-diploid transition). In photosynthetic organisms with haploid-diploid life cycles, these alternations are between two distinct multicellular generations: gametophyte and sporophyte. As both the gametophyte and sporophyte generations are constructed using information from a shared genome, it follows that epigenetic regulation processes must operate both during meiosis and during syngamy to trigger the initiation of the appropriate developmental program associated with each generation. Genetic analysis of life cycle alternation in organisms diversely distribute across the lineages of the eukaryotic tree will improve our understanding at the molecular level. Current knowledge indicates that life cycle alternation is regulated by genetic factors (homeodomain transcription factors) and by chromatin modifications. The majority of brown algae have haploid-diploid life cycle and one of these species, the filamentous brown alga Ectocarpus, is being used as a model system to study life cycle regulation. Ectocarpus has a complex life cycle. Current work has shown that alternation of generations in Ectocarpus is controlled by two homeodomain transcription factors, ORO and SAM, which regulate the induction of the sporophyte developmental program. However, alternation between the gametophyte and the sporophyte can also be regulated by a non-cell autonomous, sporophyte-inducing factor secreted into the culture media by sporophytes. This diffusible factor causes major developmental reprogramming in initial cells (meio-spores) of the gametophyte. Interestingly, current work shows that ORO and SAM may be part of the regulatory network triggered by the sporophyte-inducing factor. However, the biochemical nature of this factor is not known. The main objective of this thesis was to characterize the diffusible sporophyte-inducing factor. The work focused on optimizing production, storage and bioassay of the factor and on obtaining information about its biochemical nature. The study also investigated the relationship between the sporophyte-inducing factor and two genetic regulators, ORO and SAM, to understand the developmental pathway triggered by the factor. In addition to this work on life cycle generation identity, the thesis involved characterisation of the baseless mutant, which exhibits a similar phenotype to the distag mutant and is affected in developmental patterning during both the gametophyte and sporophyte generations
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Der, Joshua, Michael Barker, Norman Wickett, Claude dePamphilis, and Paul Wolf. "De novo characterization of the gametophyte transcriptome in bracken fern, Pteridium aquilinum." BioMed Central, 2011. http://hdl.handle.net/10150/610016.
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BACKGROUND:Because of their phylogenetic position and unique characteristics of their biology and life cycle, ferns represent an important lineage for studying the evolution of land plants. Large and complex genomes in ferns combined with the absence of economically important species have been a barrier to the development of genomic resources. However, high throughput sequencing technologies are now being widely applied to non-model species. We leveraged the Roche 454 GS-FLX Titanium pyrosequencing platform in sequencing the gametophyte transcriptome of bracken fern (Pteridium aquilinum) to develop genomic resources for evolutionary studies.RESULTS:681,722 quality and adapter trimmed reads totaling 254 Mbp were assembled de novo into 56,256 unique sequences (i.e. unigenes) with a mean length of 547.2 bp and a total assembly size of 30.8 Mbp with an average read-depth coverage of 7.0x. We estimate that 87% of the complete transcriptome has been sequenced and that all transcripts have been tagged. 61.8% of the unigenes had blastx hits in the NCBI nr protein database, representing 22,596 unique best hits. The longest open reading frame in 52.2% of the unigenes had positive domain matches in InterProScan searches. We assigned 46.2% of the unigenes with a GO functional annotation and 16.0% with an enzyme code annotation. Enzyme codes were used to retrieve and color KEGG pathway maps. A comparative genomics approach revealed a substantial proportion of genes expressed in bracken gametophytes to be shared across the genomes of Arabidopsis, Selaginella and Physcomitrella, and identified a substantial number of potentially novel fern genes. By comparing the list of Arabidopsis genes identified by blast with a list of gametophyte-specific Arabidopsis genes taken from the literature, we identified a set of potentially conserved gametophyte specific genes. We screened unigenes for repetitive sequences to identify 548 potentially-amplifiable simple sequence repeat loci and 689 expressed transposable elements.CONCLUSIONS:This study is the first comprehensive transcriptome analysis for a fern and represents an important scientific resource for comparative evolutionary and functional genomics studies in land plants. We demonstrate the utility of high-throughput sequencing of a normalized cDNA library for de novo transcriptome characterization and gene discovery in a non-model plant.
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Blischak, Leslie Anne. "Gametophytic Selection for Thermotolerance in Phalaenopsis." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/33989.
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Gametophytic selection was examined as a breeding tool in developing Phalaenopsis hybrids that are more cool or warm temperature tolerant. Two hybrid Phalaenopsis, P. (Taisoco Windian à Sogo Sogo Yukidian) by P. hybrid unknown, were reciprocally cross-pollinated and exposed to 14°C/9°C for 7 days as a cold pollination treatment. Plants were pollinated again and exposed to 30°C/25°C for 3 days for the warm pollination treatment. Each cultivar was placed in either of two growth chambers during the pollination treatments and exposed to the selected temperatures, an 11-h photoperiod with an irradiance of 180 Mmol⠢m-2⠢s-1 and a relative humidity of 70%. The plants were returned to the greenhouse after pollination and the green capsules were collected after 150 days. Seeds obtained from these treatments were surface-sterilized and equal volumes were placed on Phytamax® medium. Evaluation of protocorm development was done after 73 days on a thermogradient table ranging from 10 to 30ºC. For the first family for which reciprocal crosses were available, the number of protocorms per plate ranged from 0 in the coldest treatments to 290 at 28°C. For cold pollinated seeds, protocorm development was optimum at 22 and 28°C (means of 290 and 250 protocorms per plate, respectively) whereas the greatest protocorm development for warm pollinated seeds occurred at 20°C (103 protocorms per plate). Of the 1471 total protocorms obtained 1095 were from cold pollinations, whereas 376 were from the warm pollinations. Protocorms were evaluated for leaf and root formation 125 days after initial plating. Transfer to warm or cold incubators occurred as protocorms developed leaves and roots. Seedlings were finally transferred to dried sphagnum and placed in growth chambers set to original pollination temperatures. One year after initial plating seedlings were evaluated on the following criteria: wet weight, number of leaves, leaf area, number of roots, and root length. The pollination treatment significantly affected the number of roots per seedling whereas germination temperature during germination significantly affected the weight (g). Weight of the seedlings, number of roots and the average root length were significantly affected by the interaction between pollination treatment and germination temperature. The weight, number of leaves, and average root length were significantly affected by the interaction between pollination treatment and incubator/growth chamber. These differences indicated that seedlings derived from warm pollination were more vigorous under warm growing conditions and those derived from cold pollination were more vigorous under cold growing conditions. The significance of the interaction between pollination treatment and incubator/growth chamber indicates that gametophytic selection for thermotolerance in Phalaenopsis can be successfully used as a plant breeding tool. Additional replication is required to confirm the greater germinability of seed derived from pollination occurring over a greater range of temperatures.Master of Science
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Hafidh, Said Salim. "A study of mechanisms of cell cycle regulation in the male gametophyte of Arabidopsis thaliana." Thesis, University of Leicester, 2009. http://hdl.handle.net/2381/9930.
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The haploid male gametophyte of angiosperms has an integral role in the production of twin sperm cells necessary for the double fertilization, the essence of flowering plants. However, the mechanisms regulating sperm cell formation and cell fate specification has yet to be identified. In this study, the thesis investigates the function of key cell cycle regulators and presents characterisation of a novel pollen division mutant of Arabidopsis (duo3) that fails to produce twin sperm cells. In addition, the project also examines the activity of small RNA (smRNA) pathways as a potential mechanism that modulates native gene expression. Pollen cell-specific vectors were constructed to drive the expression of hairpin double stranded RNA (hp-dsRNA) as tools for investigating the activity of smRNA pathways, and their efficacy was tested by manipulating expression of key cell cycle regulators in Arabidopsis. Indeed, expression of hp-dsRNA intended to knockdown transcripts of Cyclin B1 members, revealed a putative role Cyclin B1 in microspore and germ cell division. Furthermore, analysis of a Cyclin B1;1 reporter led to the identification of DUO1 (a pollen specific R2R3 MYB protein) but not DUO3 as a germ cell-specific regulator of Cyclin B1;1 expression. This interaction was further verified by rescuing mutant duo1 plants with Cyclin B1;1. Analysis of DUO3 expression revealed restricted patterns confined predominantly in dividing tissues. Moreover, study of Cyclin B1;1 reporter revealed mutant duo3 cells to be impaired in degrading Cyclin B1;1 protein, suggesting a role in modulating Cyclin B1;1 activity. In summary, this work has highlighted a potential role of the Cyclin B1 family in the development of the male gametophyte. Use of Cyclin B1;1 marker has demonstrated a first example of germ cell specific integrator of cell division and cell differentiation and a putative role of DUO3 in germ cell division. A significant progress has been achieved in understanding smRNA pathways and the vectors generated will be exploited to gain more insight into the development of the male gametophyte.
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Kőszegi, Dávid. "RKD genes : a novel transcription factor family involved in the female gametophyte development of Arabidopsis and wheat." kostenfrei, 2008. http://nbn-resolving.de/urn:nbn:de:gbv:3:4-823.
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Hackenberg, Thomas [Verfasser], and Stefanie [Akademischer Betreuer] Sprunck. "Identification and Characterization of Membrane-associated Proteins of the Arabidopsis Female Gametophyte / Thomas Hackenberg ; Betreuer: Stefanie Sprunck." Regensburg : Universitätsbibliothek Regensburg, 2019. http://d-nb.info/117562523X/34.
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Siebers, Meike [Verfasser]. "The Role of Acyl-ACP Thioesterases and Glycerophosphodiester Phosphodiesterases for Gametophyte Development in Arabidopsis thaliana / Meike Siebers." Bonn : Universitäts- und Landesbibliothek Bonn, 2016. http://d-nb.info/1165650665/34.
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Rizzo, Paride [Verfasser]. "Novel insights on female gametophyte development in the apomictic model species Boechera spp. and Hypericum spp. / Paride Rizzo." Halle, 2016. http://d-nb.info/1137509848/34.
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CREPINEAU, FLORENT. "Etude comparee du gametophyte et du sporophyte de l'algue brune laminaria digitata (l. ) lamouroux par une strategie est." Paris 6, 2000. http://www.theses.fr/2000PA066498.
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Laminaria digitata est une algue brune au cycle de vie digenetique tres heteromorphe. Le sporophyte diploide est macroscopique, le gametophyte haploide est microscopique. Le sporophyte concentre l'iode jusqu'a 30,000 fois sa teneur dans l'eau de mer et produit en grande quantite l'alginate, son polysaccharide parietal majeur. Le gametophyte comme le tres jeune sporophyte sont des plantes d'ombre extreme, necessitant tres peu de lumiere pour croitre. Les genomes exprimes dans les deux phases du cycle de vie ont ete etudies et compares par une strategie est (etiquette de sequence transcrite). Pres de 700 sequences differentes ont ete produites, dont la moitie a ete identifiee par similitude avec des sequences presentes dans les banques de donnees. A la vue des transcriptomes, le sporophyte apparait comme un organisme en croissance active investissant la plupart des ses ressources dans la synthese proteique. Un transcrit codant une haloperoxydase est majoritairement exprime. Le gametophyte investi principalement ses ressources dans la synthese proteique, mais aussi dans la photosynthese. Ces resultats sont accord avec les donnees ecophysiologiques. Le gametophyte apparait comme un organisme moins differencie qui exprime peu de transcrits abondants et aucun transcrit majoritaire. L'analyse des donnees de sequencage, a permis de mieux connaitre la structure du genome transcrit de cette algue dont l'utilisation des codons ou la sequence de kozak qui sont directement applicables dans le laboratoire. Pour gerer l'ensemble des donnees, une base de donnees relationnelle et un ensemble de logiciels connexes ont ete mis en place formant un lims (laboratory information management system). Cette strategie a permis d'isoler de nombreux clones codant des proteines d'interet. Certains, impliques dans le metabolisme du carbone, ont ete caracterises. Pour d'autres, comme la bromoperoxydase probablement impliquee dans le metabolisme de l'iode ou la c-5-epimerase impliquee dans le metabolisme de l'alginate, l'etude des proteines et des familles multigeniques est en cours. Les resultats obtenus ont permis de developper de nouvelles thematiques au laboratoire. De plus, l'acces par d'autres laboratoires a ces resultats devrait permettre de nouveaux developpements de la connaissance de la biologie des algues brunes.
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Horst, Nelly [Verfasser], and Ralf [Akademischer Betreuer] Reski. "The homeobox gene BELL1 is the master regulator for the developmental switch from gametophyte to sporophyte in Physcomitrella patens." Freiburg : Universität, 2016. http://d-nb.info/111989946X/34.
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Skelton, Chanda Lee. "Investigations into gametophyte morphology and population sex ratios through direct comparisons between laboratory-grown and field-grown fern gametophytes." [Ames, Iowa : Iowa State University], 2007.
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Matsson, Sanna. "Optimal physical and chemical environment for vegetative gametophyte culture of Saccharina latissima : - with emphasis on nutrient composition and light quality." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for biologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-21422.
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The production of sporelings is a bottle-neck when cultivating Saccharina latissima. Establishing a vegetative gametophyte stocks gives a constant supply of healthy sporelings, enabling a year-round cultivation independent of the availability of natural spores. Finding optimal conditions for vegetative growth of gametophytes are of importance to produce mass quantities of sporelings. In the present study, it was desirable to establish optimal fysical and chemical environments for vegetative gametophyte culture of S. latissima which can be used in large scale cultivation systems. This were examined by five different experiments evaluating the effect of nutrient composition and light quality on growth and development on S. latissima gametophytes. The two most commonly used media when cultivating laminaria; Provasoli’s Enriched seawater (PES) and Guillard’s f/2 medium (f/2), were examined. The nutrient compisiton were examined through the addition of nitrogen (N) and phosphorous (P) in different concentrations and ratios to steralized seawater (SSW). The growth hormones kinetin (KIN) and Indole-3-acetic acid (IAA) was added in different concentrations to PES in a concentration gradient and the seaweed extract AlgeaFert was added in different concentrations to half strength PES (PES/2) due to its assumed presence of several plant growth substances. The growth of gametophytes was compared under red LED lights preventing fertility and under white florescence lights. White light contains blue wavelengths, thereby inducing fertility. Altering the nutrient ratio can be used to manipulate gametophyte cultures to grow vegetatively. The experiments conducted in white light therefore had a gradient of N:P ratios to evaluate the effect on fertility. The experiments revealed the growth of S. latissima gametophytes to be highly dependent on the chemical composition of the medium it was grown in and it had a significantly higher growth in PES compared to f/2. An increased growth was strongly affected by the presence of chelating agents, an increased concentration of N and P and a low ratio between them, and the addition of a low concentration of seaweed extract. The present study demonstrated that an alternation of light quality from red LED light to warm-white fluorescence light gave a significantly increased growth of S. latissima gametophytes. Since none of the treatments in this study resulted in fertility it cannot be concluded which treatments that inhibit fertilization and promote vegetative growth.
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Gebert, Marina. "The gametophyte specific ARM repeat protein AtARO1 is required for actin dynamics in Arabidopsis during pollen tube growth and double fertilization." kostenfrei, 2008. http://www.opus-bayern.de/uni-regensburg/volltexte/2008/1072/.
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Renault, Sylvie. "Propriétes et mécanismes des échanges de nutriments entre le gametophyte et le sporophyte chez polytrichum formosum : le rôle des cellules de transfert." Poitiers, 1991. http://www.theses.fr/1991POIT2265.
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Le plasmalemme des cellules de transfert epidermique de l'haustorium du sporophyte de polytrichum formosum cree un gradient de ph et un gradient electrique qui augmentent au cours du developpement du sporophyte. Le ph du milieu d'incubation de l'haustorium diminue de 5,2 a 4,3 et la difference de potentiel transmembranaire des cellules de transfert s'hyperpolarise de 140 mv a 210 mv, lorsque le sporophyte passe du stade 2 au stade 4 cm. La force protonmotrice entretenue par les cellules de transfert devient considerablement plus importante que celle creee par les cellules epidermiques banales et les parenchymes. Les gradients generes par les cellules de transfert sont utilises pour energiser l'absorption des acides amines provenant de l'apoplaste du gametophyte. En effet les resultats de caussin (1981) et les notres montrent que l'absorption des acides amines par les cellules de transfert du sporophyte est un symport proton/acide amine energise par une pompe a protons. Le saccharose est probablement la forme principale de transport des glucides dans les tissus conducteurs de polytrichum. Cependant, les glucides collectes dans l'apoplaste de la vaginule sont des hexoses (glucose, fructose). Ceux-ci proviennent de l'hydrolyse du saccharose a l'interface gametophyte/sporophyte ou une importante activite invertasique a ete decelee. L'absorption des hexoses (glucose, 3-0-meg) est quasi insensible a ph et. Le 3-0-meg, non metabolisable, est transporte par diffusion suivant son gradient de concentration. Le glucose est converti en saccharose suite a son absorption par les tissus de l'haustorium. Cette conversion consommatrice d'energie joue probablement un role dans l'accumulation apparente de ce substrat dans l'haustorium
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Kong, Jixiang [Verfasser], and Gerd [Gutachter] Jürgens. "Cell fate specification and maintenance in the female gametophyte and transcriptional profiling of early embryos in Arabidopsis thaliana / Jixiang Kong ; Gutachter: Gerd Jürgens." Tübingen : Universitätsbibliothek Tübingen, 2014. http://d-nb.info/1197058788/34.
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Spat, Cristiele. "CARACTERIZAÇÃO ESTRUTURAL DA EMBRIOLOGIA EM TILLANDSIA AERANTHOS (LOIS.) L. B. SM. (TILLANDSIOIDEAE-BROMELIACEAE)." Universidade Federal de Santa Maria, 2012. http://repositorio.ufsm.br/handle/1/4852.
Full textAbstract:
Bromeliaceae owns a huge diversity of species in the Neotropical region, comprising about
3140 species, in which 551 consist of the genus Tillandsia. The article aims the descritption,
of the anther development and ovule as the esporogenesis and gametogenesis characterization
as well, in order to make easier both the taxonomy and philogeny of the family, which is still
in process of change. Tillandsia aeranthos (Lois.) L. B. Sm. contains six stamens flowers;
superior, tricarpellate and trilocular ovary. The pattern of development of the anther wall is
characterized as mixed-type. Androsporangium is formed by epidermis, middle layers,
endothecium and tapetum. The tapetum is the secretor-type. Meiosis is the successive-type
with cleavage of the centrifugal type. The tetrads formed are decussate or isobilateral. The
first division of the pollen is preceded by vacuolation, it is assymmetric and produce both
generative and vegetative cells. The two cells formed are separated by a callose wall. The
mature grain pollen is bicelullar. The ovule of Tillandsia aeranthos is anatropus, bitegmic and
crassinucellate, with axial placentation. The ovule originates in the subdermal layer (zone II)
of the placentae. The integument nucellar epidermis is originated by divisions in the dermal
layers. One to three ginospore mother celss, which are originated by divisions in archesporial
cell, undergo meiotic divisions development a linear tetrad, with presence callosic wall. Only
the chalazal ginospore becomes functional. The functional ginospore differs in that a
gametophyte uninucleate after mitosis and yields a two-nucleate and four-nucleate
gametophyte. The female gametophyte has a monosporic origin and a Polygonum-type
development. The female gametophyte consists of two synergids, an egg cell, three antipodes
and two polar nuclei. Polar nuclei fuse prior to fertilization.Bromeliaceae possui grande diversidade de espécies na região neotropical, compreendendo cerca de 3140 espécies, sendo 551 do gênero Tillandsia. O presente trabalho teve como objetivo descrever o desenvolvimento da antera e do rudimento seminal, além da caracterização da espogênese e gametogênese, com a finalidade de auxiliar na taxonomia e filogenia da família, ainda em fase de mudança. Tillandsia aeranthos, apresenta flores com estames em número de seis e ovário súpero, tricarpelar. Na antera, o desenvolvimento dos estratos parietais é do tipo misto , formado por epiderme, endotécio, camada média e tapete. A epiderme é papilada e o tapete é do tipo secretor. A microsporogênese é sucessiva com clivagem do tipo centrífuga, onde são formadas tétrades isobilaterais e decussadas. Após a liberação do andróspro da tétrade, ocorre a primeira divisão do grão de pólen e é precedida por vacuolação. Após mitose, é formada a célula generativa e a célula vegetativa, separadas por uma parede de calose. O andrófito é liberado bicelular. O rudimento seminal de Tillandsia aeranthos é anátropo, bitegumentado e crassinucelado, com placentação axial. O rudimento seminal tem origem na camada subdérmica da placenta. Os tegumentos são de origem dérmica. A inicial arquesporial dá origem á célula mãe de ginósporo (CMG). A CMG sofre o primeiro ciclo meiótico que origina uma díade de ginósporo com presença de calose ao redor. O segundo ciclo meiótico dá origem a tétrade linear de ginósporo, tornando-se o ginósporo calazal funcional. O ginósporo funcional diferencia-se em um gametófito uninucleado que após mitoses origina um gametófito bi e tetranucleado. Esse tipo de desenvolvimento do ginófito é do tipo monospórico e Polygonum, onde o ginófito apresenta sete células e oito núcleos, com a presença de duas sinérgides, uma oosfera, formando o aparelho oosférico e três antípodas. Os núcleos polares de fusionam antes da fecundação.
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Kőszegi, Dávid [Verfasser], Gerd Akademischer Betreuer] Jürgens, Gunter [Akademischer Betreuer] Reuter, and Ulrich [Akademischer Betreuer] [Wobus. "RKD genes: a novel transcription factor family involved in the female gametophyte development of Arabidopsis and wheat / Dávid Kőszegi. Betreuer: Gerd Jürgens ; Gunter Reuter ; Ulrich Wobus." Halle, Saale : Universitäts- und Landesbibliothek Sachsen-Anhalt, 2008. http://d-nb.info/1024874583/34.
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Šoljić, Lucija [Verfasser], Thomas [Akademischer Betreuer] Dresselhaus, and Stephan [Akademischer Betreuer] Schneuwly. "Microarray analysis of single isolated cells of the female gametophyte reveals potential regulators of female germline development in Arabidopsis thaliana / Lucija Soljic. Betreuer: Thomas Dresselhaus ; Stephan Schneuwly." Regensburg : Universitätsbibliothek Regensburg, 2012. http://d-nb.info/1030179379/34.
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Šoljić, Lucija Verfasser], Thomas [Akademischer Betreuer] [Dresselhaus, and Stephan [Akademischer Betreuer] Schneuwly. "Microarray analysis of single isolated cells of the female gametophyte reveals potential regulators of female germline development in Arabidopsis thaliana / Lucija Soljic. Betreuer: Thomas Dresselhaus ; Stephan Schneuwly." Regensburg : Universitätsbibliothek Regensburg, 2012. http://d-nb.info/1030179379/34.
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Sante, Richard R. T. "Occurrence and Implications of the N-Acylethanolamine Metabolic Pathway in Physcomitrella patens." Digital Commons @ East Tennessee State University, 2014. https://dc.etsu.edu/etd/2383.
Full textAbstract:
N-acylethanolamines (NAEs) with C12-C18 acyl chain are ubiquitous in seed plants and play a role in mediating abscisic acid (ABA)-dependent or -independent responses to stress. In moss Physcomitrella patens, using selective lipidomics approach, we recently identified the occurrence of anandamide or N-arachidonylethanolamide (NAE 20:4) and its precursors that were previously not reported in plants. Occurrence of anandamide in moss provides us with a unique opportunity to address if early land plants retained NAE-mediated signaling mechanism that is akin to animals but not to vascular plants. It is hypothesized that a distinctive NAE profile and metabolic pathway occurs in P. patens. To this extent, putative genes that might be responsible for anandamide metabolic pathway were identified and their expression levels were determined for three developmental stages of moss. The NAE metabolite levels and transcript levels for putative genes were higher in protonema stage and anandamide showed higher growth inhibitory effects, chlorophyll reduction, and putative gene induction than NAE 12:0, compared to ABA, when applied exogenously.
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LE, THI KINH. "Genetique du gametophyte male du mil (pennisetum typhoides stapt et hubb) : relations entre overlapping et l'organisation de la variabilite genetique des plantes haploides doublees (h.d.) issues de culture d'anthere." Paris 11, 1990. http://www.theses.fr/1990PA112134.
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L'etude des relations entre overlapping et l'organisation de la variabilite genetique des plantes androgenetiques chez le mil (pennisetum typhoides stapt et hubb) a ete realisee sur differentes structures: lignees, f1, populations cultivees et sauvages, descendances des haploides doublees issues d'un croisement f1 (massues ligui). L'analyse des caracteres enzymatiques a montre, au niveau du gametophyte male, l'expression postmeiotique de tous les genes testes (adh, a, est e, cat, pgi, mdh b). Ainsi, le domaine de gametophyte-sporophyte overlapping concerne 61% des genes de structure. Des analyses unies et multivariees, realisees sur les caracteres quantitatifs dans les descendances des plantes hd, ont montre une variabilite inter et intra-descendance importante. Par ailleurs, dans ces descendances, la transmission des alleles massue a ete pratiquement toujours avantagee. L'analyse des caracteres enzymatiques et caryotypiques a montre dans les descendances androgenetiques, une certaine heterozygotie au niveau des caracteres monogeniques, l'apparition d'une bande inhabituelle dans le profil de l'est e, ainsi que des phenomenes d'hyperaneuploidie, de mixoploidie, de retard considerable dans la spiralisation des chromosomes et de la presence de chromosomes b
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Wu, Di. "Discovery and characterization of a signaling molecule regulating somatic embryogenesis in loblolly pine." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/28252.
Full textAbstract:
Thesis (M. S.)--Chemistry and Biochemistry, Georgia Institute of Technology, 2008.Committee Chair: Dr. Sheldon May; Committee Member: Dr. Donald Doyle; Committee Member: Dr. Gerald Pullman; Committee Member: Dr. James Powers; Committee Member: Dr. Nicholas Hud.
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Töller, Armin [Verfasser], Paul [Akademischer Betreuer] Schulze-Lefert, and Martin [Akademischer Betreuer] Hülskamp. "Studies of plant innate immunity provide new functional insights on class IIa WRKY transcription factors and reveals a role for two Glucan Synthase-Like genes in gametophyte development / Armin Töller. Gutachter: Paul Schulze-Lefert ; Martin Hülskamp." Köln : Universitäts- und Stadtbibliothek Köln, 2011. http://d-nb.info/1038064929/34.
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Rodrigo-Peiris, Thushani. "Unraveling the Functions of Plant Ran GTPase-Activating Protein (RanGAP) by T-DNA Mutant Analysis and Investigation of Molecular Interactions of Tandem Zinc Finger 1 (TZF1) in Arabidopsis thaliana." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1343796551.
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Dubald, Manuel. "L'exopolygalacturonase de maïs : caractérisation de la protéine, et analyse par transgénèse du promoteur d'un gène codant pour cette enzyme." Université Joseph Fourier (Grenoble), 1993. http://www.theses.fr/1993GRE10187.
Full textAbstract:
L'exopolygalacturonase (exopg) est une enzyme pectolytique particulierement abondante dans le pollen mature de mais. Les genes exopg sont exprimes tardivement au cours du developpement du gametophyte male. L'enzyme n'est detectee qu'apres la completion des mitoses polliniques, puis est synthetisee en quantites croissantes jusqu'a la fin de la microsporogenese. Ce profil d'expression suggere que l'exopg joue un role au moment de la germination et de la croissance du tube pollinique. Deux isoformes de 49 et 53 kda ont ete identifiees et caracterisees dans une fraction purifiee a partir de pollen mature de mais. D'importantes modifications post-traductionnelles ont ete mises en evidence : (i) un peptide hydrophobe de 22 residus est clive de la region nh 2 - terminale de la proteine, (ii) des motifs glucidiques sont branches sur certains residus asparagine. Ces modifications indiquent que, lors de sa traduction, le precurseur de l'exopg est transfere dans le reticulum endoplasmique, ce qui s'accompagne du clivage d'un peptide signal, et qu'il y est glycosyle. D'autres isoformes de l'exopg ont ete detectees dans le pollen mature, qui correspondent vraisemblablement a d'autres etats de glycosylation de la proteine. L'exopg a ete localisee par immunocytochimie a l'interieur de la cellule vegetative dans le pollen mature. Au moment de la germination, l'enzyme est secretee dans la paroi du tube pollinique. L'exopg n'est pas exprimee uniquement dans le gametophyte male. Son activite enzymatique a egalement ete detectee dans tous les tissus sporophytiques examines. Dans les tissus vegetatifs, l'exopg est revelee par immunocytochimie essentiellement au niveau des parois cellulaires. L'ubiquite de cette enzyme suggere un role cellulaire general, sans doute dans la formation de la paroi. L'activite du promoteur d'un gene exopg de mais a ete analysee a l'aide du gene rapporteur gus dans des plantes transgeniques de tabac. Les genes chimeres sont fortement exprimes dans les microspores de tabac, apres la mitose pollinique. Une activite gus plus faible a egalement ete detectee dans les graines et la tige. En revanche, le promoteur de mais n'est actif ni dans les feuilles ni dans les racines des plantes transgeniques. Des resultats differents et contradictoires ont ete observes en expression transitoire dans le tabac et le mais. Les elements cis essentiels pour l'activite de ce promoteur exopg sont presents dans le fragment 366/+128, la numerotation etant relative au site d'initiation de la transcription des genes chimeres dans le tabac. Le fragment 25/+128 induit une activite du gene rapporteur gus, faible mais significative, uniquement dans les microspores des plantes transgeniques.
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Carroll, Kirstin Arthur. "A role for maize ROP2 GTPase in the male gametophyte." Thesis, 2004. http://hdl.handle.net/1957/29912.
Full textAbstract:
ROP GTPases are crucial regulators of pollen tube growth. The Rop GTPase family in maize consists
of nine known rop genes, ropl-rop9. A subset of these genes (rop2, rop8, and rop9) are expressed in
pollen. The rop2 and rop9 genes are a highly conserved duplicate gene pair of ancient origin. The
rop2/rop9 duplicate gene pair displays differential expression in mature and germinated pollen,
suggesting different roles for the genes in the process of male gametophyte development. To explore
ROP2 function in maize, five Mutator transposon insertions in the rop2 gene were isolated (rop2::Mu
alleles). I showed that three of the rop2::Mu alleles displayed reduced transmission through the male
and were associated with reduced levels of ROP2-mRNA. Interestingly, the rop2::Mu male-specific
transmission defect was apparent only when wild-type pollen was also present, an indication that the
mutation reduces the competitive ability of the rop2 gametophytes. Dual pollination and pollen
mixing experiments indicated that this competitive disadvantage is expressed by the majority of the
mutant gametophytes, and that expression of the phenotype is associated with a delay in the ability to
accomplish fertilization. Using the waxy phenotypic marker (linked to rop2 via a reciprocal
translocation) to distinguish between rop2::Mu and wild-type pollen derived from heterozygous plants,
I demonstrated that the delay is associated with a defect in early progamic development (i.e,
germination and early pollen tube growth). The defect was detectable in vivo as early as 15 minutes
after pollination. However, quantitative measurements provided no indication that the rop2 mutation
affects pollen tube growth in the style. Finally, investigations focusing on the final stages of pollen
function raise the possibility that a defect in the very last stages (i.e. either pollen tube guidance
through the micropyle to the egg sac, or fertilization of the egg sac) may also contribute to the rop2
mutant delay. This work provides direct in vivo evidence confirming a role for Rop in male
gametophyte development, and is the first study to demonstrate a role for Rop in the early stages of
post-pollination gametophytic function.Graduation date: 2005
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REŇÁK, David. "Role of transcription factors in early male gametophyte development of Arabidopsis." Doctoral thesis, 2011. http://www.nusl.cz/ntk/nusl-55691.
Full textAbstract:
In the presented work the relationship between transcription factors and male gametophyte development was studied. The Ph.D. Thesis covers selection of candidate genes, wide-scale screening of T-DNA mutant lines and detailed analysis of a selected transcription factor on pollen development.
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Qi, Hanshi. "Cultivation of Laminaria saccharina gametophyte cell cultures in a stirred-tank photobioreactor." Thesis, 1994. http://hdl.handle.net/1957/35766.
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Carney, Laura Truesdale. "The biology of kelp gametophyte banks in a southern California kelp forest." Diss., 2009. http://proquest.umi.com/pqdweb?did=1985302651&sid=1&Fmt=2&clientId=48051&RQT=309&VName=PQD.
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Hsu, Wei-Han, and 許巍瀚. "Functional analysis of genes regulating cell division and gametophyte development in Arabidopsis." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/tuje6h.
Full textAbstract:
博士國立中興大學
生物科技學研究所
100
How to suppress the cell division in the differentiated cells but not the meristematic cells is largely unknown in plants. The family of Yippee-like (YPEL) genes has been found in various eukaryote species. However, no study on YPEL genes has been reported in plant species. In this study, an Arabidopsis YPEL gene AtYIP1 was characterized. The promoter::GUS assay indicated that AtYIP1 mRNA was constitutively expressed in all tissues except meristematic cells and the AtYIP1 proteins were degraded constantly in cells without further division. Hastened growth and increased size and cell number of leaf were observed in 35S::AtYIP1 RNAi plants. By contrast, growth in the 35S::AtYIP1 plants ectopically expressing AtYIP1 was significantly inhibited. The anatomical analysis revealed that the severe 35S::AtYIP1 mutant phenotype is primarily due to the lack of the cell division in both shoot and root apical meristem. These results revealed a repressor role for AtYIP1 in preventing cell division in Arabidopsis. This assumption was further supported by the suppression of the cells growth for tobacco cell line BY-2 and human embryonic kidney cell line HEK 293T after transfection with flag-tagged AtYIP1. Furthermore, AtYIP1 proteins were found to be able to suppress the abnormal cell division for differentiated cells by entering nucleus and bind to DNA. Our data represents a novel finding that a plant gene is able to suppress cell division and growth in both plant and animal system. (Chapter 1) Arabidopsis AGL13 is the gene classified as AGL6 lineage of MIKC type MADS-box gene family. Our previous study indicated that AGL13 expression was specifically detected from the initiation to maturation of both pollen and ovules. Ectopic expression of AGL13 RNAi construct was found to cause sterility by inducing the production of flowers with defective pollen and ovules in transgenic Arabidopsis plants. In this study, two types of pollen in equal numbers were found in 35S::AGL13 RNAi/qrt1-2 tetrads. The first type resembles wild-type whereas the second type is reduced in size with a flat or collapsed shape, suggesting that the development of the pollen grains that carried the 35S::AGL13 RNAi was arrested during meiosis. The viability of the wild-type like pollen in AGL13 RNAi plants was tested by adhesion assay and pollination assay. These data indicated that AGL13 not only regulates pollen development but also controls the tapetum function for exine formation. The enhancement of the alteration of pollen development, the sterility of the plants and the flower organ formation in AGL13:SRDX (containing a suppression motif) transgenic plants suggested that AGL13 acts as a repressor. Furthermore, similar defects in floral organs was observed in AGL13:SRDX and SEP2:SRDX plants which was caused by the suppression of the expression for A, B and C function MADS-box genes. AGL13 could interact with B, C function MADS-box protein and form complex to regulated downstream genes expression, including the pollen developing and tapetum formation genes. (Chapter 2) Finally, series systems of binary vectors have been generated for plant molecular cloning and functional study. All vectors share the same restriction enzyme cloning sites, and contain different combinations of promoters, fusion tags and selection markers. These vectors can be applied to the experimental assays of ectopic expression, RNA silencing, fluorescent tags fusion, heat inducible expression, monocot transformation, dominant negative repression, dominant positive activation, trans-expression. New vectors provided the additional construction procedures for the lab and the experiment assay could be designed with systematically work through standard operating procedure (SOP). (Chapter 3)
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Tai, Shih-Hsin, and 戴世昕. "Aquaculture Development of different generation of Thalloid Sporophyte and Gametophyte of Grateloupia taiwanensis." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/85119990204169529472.
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碩士國立臺灣大學
漁業科學研究所
101
Grateloupia is a commercial macroalgal which belonging to the phyla of Rhodophyta under the order of Halymeniales. Field collection from the intertidal zone of Taiwan North-eastern coast, Grateloupia has been widely consumed as a delicacy by the local people. Wild Grateloupia was hand-picked by snorkelers in an inefficient way. Thus, the production of Grateloupia was limited and unable to meet the demand from the market. Despite this fact, very few researches on the cultivation of Grateloupia were done on the production of Grateloupia at commercial scale. In this study, the propagation of Grateloupia taiwanensis nodulous filament for germ stock and seedling development was investigated. The nodulous filaments were prepared from germinating carporspores and tetraspores separately. Discoid crust from germinating spores were detached from the substrat, and maintained in enriched medium. Subsequently, various conditions to scale-up the production of nodulus filament cultures were determined. The nodulus filaments were blended into small fragments which were capable in forming new discoid crusts under appropriate conditions. At 20℃, under high illumination of light (7000 lux), young shoots formed from the crusts. The young shoots were transferred to outdoor environment for further growth under appropriate conditions. It was also observed that diploid nodulus filaments germinated from carpospores grew better at higher temperature compared to the haploid nodulous filaments, which were germinated from tetraspores. Most of the discoid crusts formed from diploid nodulous filaments and carpospores were smaller in size, and were easily detached from substrate. Therefore, we suggest that nodulus filaments from detached diploid discoid crusts is an ideal source of seedlings which can be cultivated in suspension. During its growing season, the length of thalli developed from the diploid nodulus filaments reached about 10-20 cm. However, the morphology of the thallus is significantly different from those collected from the field. We suggest that the indoor cultivation of seedling sources to be improved at larger scale. The life cycle of Grateloupia may also can be determined artificially using this technique.
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Anderson, Cindy Louise. "Gametophyte development in Cheilanthes Viridis Var. Glauca (adiantaceae) with special reference to Apogamy." Thesis, 1992. http://hdl.handle.net/10539/22179.
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A dissertation submitted to the faculty of science
university of the Witwatersrand, Johannesburg
for the Degree of Master of Science
Johannesburg
1992The gametophyte generation of the fern life cycle is initiated with the formation of spores. The spores of C. viridis (Fonsic) Swarts var. glaeca (Sim) schelp Anthony are trilete and have a cristate spore wall ornamentation. Under favourable conditions the spores of C. viridis var. glauca show polar germination [Abbreviated Abstract. Open document to view full version]
GR2017
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Zhi, Chunxing. "Cultivation of Laminaria saccharina gametophyte cell cultures and Acrosiphonia coalita tissue cultures in a bubble-column photobioreactor." Thesis, 1994. http://hdl.handle.net/1957/35536.
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[Verfasser], Kanok-orn Srilunchang. "Molecular characterization and identification of genes involved in maize female gametophyte development / vorgelegt von Kanok-orn Srilunchang." 2009. http://d-nb.info/997895004/34.
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Arias-Garzón, Tatiana. "Embryology of Manekia naranjoana (Piperaceae) and its implications for the origin of the sixteen-nucleate female gametophyte in Piperales." 2007. http://etd.utk.edu/2007/Theses/AriasGarzonTatiana.pdf.
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Daigle, Caroline. "Expansion d'une nouvelle famille de protéines kinases (MAPKKKs) impliquée dans le développement reproductif chez les Solanacées." Thèse, 2016. http://hdl.handle.net/1866/18509.
Full textAbstract:
Les cascades de Mitogen-Activated Protein Kinases (MAPKs) sont présentes chez tous les eucaryotes et permettent la transduction des signaux de l’extérieur vers l’intérieur de la cellule. Chez les végétaux, elles sont très abondantes et actives dans une multitude de processus, autant lors de la réponse aux stress que lors du développement. Elles fonctionnent comme un système de phosphorelais, se transférant un groupement phosphate d’une protéine à l’autre, de la MAPKKK à la MAPKK (MKK), puis de la MKK à la MAPK (MPK) et finalement, de la MPK vers des facteurs de transcription ou toute autre protéine qui permettra un changement au niveau de la réponse cellulaire.
Depuis quelques années, plusieurs membres de la grande famille des MAPKs ont été étudiés pour leur rôle dans la reproduction sexuée des végétaux. Des mutants ont été caractérisés, mais jusqu’à maintenant, peu de voies complètes ont été décelées. Des précédents travaux dans le laboratoire ont démontré que deux MAPKKKs, de la sous-famille des MEKKs, ScFRK1 et ScFRK2, sont importantes pour le développement normal de l’ovule et du pollen chez Solanum chacoense, une espèce de pomme de terre sauvage diploïde. Sachant que les mutants des gènes les plus orthologues chez Arabidopsis thaliana ne possèdent pas les mêmes phénotypes, nous avons émis l’hypothèse que les Solanacées, du moins S. chacoense, possèdent une famille de MAPKKKs différente, qui n’est pas présente chez A. thaliana.
Nous avons donc analysé les génomes/transcriptomes/protéomes de 15 espèces issues de différents clades du règne végétal afin d’étudier les relations phylogénétiques à l’intérieur de la sous-famille des MEKKs. Cela nous a permis d’observer que ScFRK1 et ScFRK2 ne sont pas seuls, mais sont inclus dans un groupe monophylétique que nous avons nommé la classe des FRKs (FRK pour Fertilization-Related Kinase). De plus, nous avons observé une expansion considérable de cette classe chez les Solanacées, comparativement à d’autres dicotylédones comme le peuplier, la vigne ou le coton. La classe des FRKs est absente chez les monocotylédones étudiées (riz et maïs) et ne possède qu’un seul membre (une FRK primitive) chez l’angiosperme basal Amborella trichopoda. Cette analyse phylogénétique des MEKKs nous a poussés à nous poser des questions sur l’origine de la classe des FRKs ainsi que sur son rôle au sein des Solanacées.
Dans un deuxième temps, nous avons fait la caractérisation fonctionnelle de ScFRK3, un troisième membre de la classe des FRKs chez S. chacoense, aussi impliqué dans le développement des gamétophytes mâle et femelle. Du patron d’expression jusqu’à l’établissement d’une voie de signalisation potentielle, en passant par la caractérisation phénotypique des mutants, plusieurs expériences ont été réalisées dans le but de comprendre le rôle de ScFRK3 au niveau de la reproduction chez S. chacoense. Dans un contexte plus global, il est important de se questionner sur les rôles semblables, mais forcément différents, des trois membres de la famille FRKs qui ont été caractérisés jusqu’à présent.Mitogen-Activated Protein Kinases (MAPKs) signaling cascades are found in all Eucaryotes and allow signal transduction from the outside of the cell to the inside. In plants, they are particularly numerous and play roles in several signaling processes, including stress responses and response to developmental cues. Their system involves a phosphorelay: they interact with each other to transfer a phosphate group. It starts with an activated MAPKKK, which transfers the phosphate group to a MAPKK (MKK), then this MKK transfers the signal to a MAPK (MPK), which ends this relay by phosphorylating transcription factors or any other proteins that will, in a way or an other, change the cell response according to the signal. During the last few years, many MAPKs members have been studied for their role in plants sexual reproduction. Some mutants were characterized, but until now, our knowledge of complete signaling cascades is very limited. Previous studies in our lab have shown that two MAPKKKs from the MEKK subfamily, ScFRK1 and ScFRK2, are important for male and female gametophytes development in Solanum chacoense, a wild diploid potato species. Genes that are the most orthologous to ScFRK1 and ScFRK2 in Arabidopsis thaliana, AtMAPKKK19, 20 and 21, do not seem to play the same roles in reproduction, which led us to make the hypothesis that in solanaceous species, at least in S. chacoense, there is one MAPKKK family that is different and not present in A. thaliana. At first, we did analyze the genomes/transcriptomes/proteomes of 15 species from different clads of the plant kingdom to find all the members of the MEKK subfamily of MAPKKKs in order to study their phylogenetic relationship. We then observed that ScFRK1 and ScFRK2 are included in a large monophyletic group which was called the FRK class (Fertilization Related Kinase). Moreover, we also observed that this class has considerably expanded within the solanaceous species, compared to other species like A. thaliana, poplar, cotton or grape vine. The FRK class is totally absent in the monocot species studied (rice and maize) and only one member is found in the basal angiosperm Amborella trichopoda. This phylogenetic analysis led us to ask questions about the origins of the FRK class and its role inside the Solanaceae family. Secondly, we characterized ScFRK3, a third member of the FRK class in S. chacoense, which is also involved, as its two FRK sisters, in male and female gametophytes development. From its expression pattern to the establishment of a potential signaling cascade, analysis and phenotyping of ScFRK3 mutant lines, many experiments were realized in order to understand the role of ScFRK3 in S. chacoense sexual reproduction. Overall, the appearance of this new and expanded class of MEKKs questions its specific role in comparison to other species that have much lesser members, mainly when compared to the model plant A. thaliana, which harbor only a fifth of the FRKs found in solanaceous species.
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Arias-Garzón, Tatiana. "Embryology of Manekia naranjoana (Piperaceae) and its Implications for the Origin of the Sixteen-nucleate Female Gametophyte in Piperales." 2007. http://trace.tennessee.edu/utk_gradthes/234.
Full textAbstract:
Piperaceae is unique among Piperales because it is the only tetrasporic group in the order and a great deal of diversity in the ontogenetic trajectories of the female gametophyte is found in its genera. The evolutionary developmental origin of the sixteen-nucleate female gametophyte remains unclear in the family until now. In Piperaceae, Manekia has been identified as sister to Zippelia, and this clade is sister to core Piperaceae (Piper, Peperomia). This research is the first attempt to understand the development of the female gametophyte of Manekia naranjoana in order to provide critical data on the origin of tetrasporic development in the family. Several aspects of the floral biology and phenological events taking place in the ovary, the flower and the inflorescence were explored. Manekia has a tetrasporic, sixteen nuclei female gametophyte, that is being produced from a single archesporial cell. The egg apparatus is located at the micropylar end of the female gametophyte. It is constituted of three cells, two synergids and an egg. The central cell nuclei consist of two nuclei, one from the micropylar end and the other one from the chalazal one. The eleven remaining nuclei are arranged toward the chalazal pole of the female gametophyte, and sometimes fuse. This description corresponds mostly to the Drusa type. But Penaea type is also occasionally reported for first time in this study for the genus. Manekia and Zippelia share a similar structure of the female gametophyte with a total of 16 nuclei, and two nuclei in a central cell suggesting a triploid endosperm. The transition from monosporic to tetraporic female gametophyte development can be explained through the theory of modular construction and several kind modifications in the ontogenetic trajectories. Heterochronic and heterotopic changes, additions, and deletions in the development of the female gametophytes reflect evolutionary histories of the particular taxa implicated. A great deal of plasticity in terms of lack of polarity and nuclear fusion of antipodals was found in the chalazal module of the female gametophyte of Manekia.
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Gebert, Marina [Verfasser]. "The gametophyte specific ARM repeat protein AtARO1 is required for actin dynamics in Arabidopsis during pollen tube growth and double fertilization / by Marina Gebert." 2008. http://d-nb.info/991466446/34.
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Raabe, Karel. "Charakterizace podjednotky A eukaryotického translačního iniciačního faktoru 3 a její role v Arabidopsis thaliana." Master's thesis, 2020. http://www.nusl.cz/ntk/nusl-436005.
Full textAbstract:
In plants, translation regulation plays an important role during progamic phase, fertilization and seed development. The process of translation is mostly regulated in its initiation phase, where Eukaryotic translation initiation factor 3 (eIF3) is the largest and most complex initiation factor, consisting of 12 different subunits. In plants, single eIF3 subunit mutants caused various growth and development defects, depending on the particular subunit that was mutated. However, not all the plant eIF3 subunits were characterized to this date. The objective of this work was to functionally characterize the eIF3 subunit A using Arabidopsis thaliana as the main model plant. We described in this work that plant eIF3A proteins share high levels of homology and domain organization with eIF3A subunits from non-plant eukaryotic species but contain regions specific only to plants. Next we described that Arabidopsis thaliana AteIF3A gene is transcribed in highly proliferating tissues, its protein product localizes to cytoplasm and around pollen vegetative cell nucleus and observed an increased frequency of defective pollen grains and defects in seed formation in plants with T-DNA insertion localized to the AteIF3A gene. We also produced stable transgenic Nicotiana tabacum lines expressing heterologous AteIF3A...
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Kočová, Helena. "Funkční charakterizace proteinů rodiny Alba u huseníčku rolního." Master's thesis, 2020. http://www.nusl.cz/ntk/nusl-435965.
Full textAbstract:
(anglicky) Alba-family proteins were identified in Archaea and Eucarya and are classified among the oldest and the most conserved nucleic acid-binding proteins. The binding preferences and roles differ among certain evolution clades. In Crenarchaea they represent chromatin-binding proteins, while their role in RNA metabolism is suggested in Euryarchaea and Eukaryotes. ALBA proteins are well characterized in human, where they play a role in the RNAse P/MRP complex and in unicellular parasites, such as Plasmodium and Trypanosoma, where an involvement in the life cycle regulation is confirmed. In plants, their role is not yet well understood. The aim of this thesis is to increase a knowledge about the Alba-family proteins in the model plant Arabidopsis thaliana. Based on a minimal changes to development and reproduction in single mutants and high sequence similarity, a functional redundancy of the proteins was assumed. For better understanding of the ALBA proteins function, three smaller members of the family were edited by the same metod. The obtained triple mutant showed delay in flowering. ALBA dimer formation was confirmed in many organisms. BiFC method was used to determine Arabidopsis ALBA homodimerization. The data analysis showed potential homodimerization in most of them.
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Fíla, Jan. "Úloha fosforylace proteinů v progamické fázi vývoje samčího gametofytu tabáku." Doctoral thesis, 2016. http://www.nusl.cz/ntk/nusl-341981.
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v angličtině (English abstract) Tobacco male gametophyte has a strongly dehydrated cytoplasm and represents a metabolically inactive stage. Upon cytoplasm rehydration, pollen grain becomes metabolically active and after the activation is finished, the pollen tube growth through a selected pollen aperture starts. The rehydration together with metabolic activation are accompanied by the regulation of translation and post-translational modifications (mainly phosphorylation) of the existing proteins. In this Ph.D. thesis, there were identified phosphopeptides from tobacco (Nicotiana tabacum) mature pollen, pollen activated in vitro 5 min and pollen activated in vitro 30 min. The total proteins from the above male gametophyte stages were extracted. The protein extract was trypsinized and the acquired peptide mixture was enriched by MOAC (metal oxide/hydroxide affinity chromatography) with titanium dioxide matrix. The enriched fraction was subjected to liquid chromatography coupled with tandem mass spectrometry (LC- MS/MS). Totally, there were identified 471 phosphopeptides, carrying 432 exactly localized phosphorylation sites. The acquired peptide identifications were mapped to 301 phosphoproteins that were placed into 13 functional categories, dominant of which were transcription, protein synthesis,...
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Chevalier, Eric. "Implication des peptides RALFs dans les communications cellulaires lors du développement du gamétophyte femelle chez Solanum chacoense et Arabidopsis thaliana." Thèse, 2012. http://hdl.handle.net/1866/9710.
Full textAbstract:
Chez les angiospermes, la reproduction passe par la double fécondation. Le tube pollinique délivre deux cellules spermatiques au sein du gamétophyte femelle. Une cellule féconde la cellule œuf pour produire un zygote; l’autre féconde la cellule centrale pour produire l’endosperme. Pour assurer un succès reproductif, le développement du gamétophyte femelle au sein de l’ovule doit établir un patron cellulaire qui favorise les interactions avec le tube pollinique et les cellules spermatiques. Pour ce faire, un dialogue doit s’établir entre les différentes cellules de l’ovule lors de son développement, de même que lors de la fécondation. D’ailleurs, plusieurs types de communications intercellulaires sont supposées suite à la caractérisation de plusieurs mutants développementaux. De même, ces communications semblent persister au sein du zygote et de l’endosperme pour permettre la formation d’un embryon viable au sein de la graine. Malgré les développements récents qui ont permis de trouver des molécules de signalisation supportant les modèles d’interactions cellulaires avancés par la communauté scientifique, les voies de signalisation sont de loin très incomplètes.
Dans le but de caractériser des gènes encodant des protéines de signalisation potentiellement impliqués dans la reproduction chez Solanum chacoense, l’analyse d’expression des gènes de type RALF présents dans une banque d’ESTs (Expressed Sequence Tags) spécifiques à l’ovule après fécondation a été entreprise. RALF, Rapid Alcalinization Factor, est un peptide de 5 kDa qui fait partie de la superfamille des «protéines riches en cystéines (CRPs)», dont les rôles physiologiques au sein de la plante sont multiples. Cette analyse d’expression a conduit à une analyse approfondie de ScRALF3, dont l’expression au sein de la plante se limite essentiellement à l’ovule. L’analyse de plantes transgéniques d’interférence pour le gène ScRALF3 a révélé un rôle particulier lors de la mégagamétogénèse. Les plantes transgéniques présentent des divisions mitotiques anormales qui empêchent le développement complet du sac embryonnaire. Le positionnement des noyaux, de même que la synchronisation des divisions au sein du syncytium, semblent responsables de cette perte de progression lors de la mégagamétogénèse. L’isolement du promoteur de même que l’analyse plus précise d’expression au sein de l’ovule révèle une localisation sporophytique du transcrit. La voie de signalisation de l’auxine régule également la transcription de ScRALF3. De surcroît, ScRALF3 est un peptide empruntant la voie de sécrétion médiée par le réticulum endoplasmique et l’appareil de Golgi. En somme, ScRALF3 est un important facteur facilitant la communication entre le sporophyte et le gamétophyte pour amener à maturité le sac embryonnaire. L’identification d’un orthologue potentiel chez Arabidopsis thaliana a conduit à la caractérisation de AtRALF34. L’absence de phénotype lors du développement du sac embryonnaire suggère, cependant, de la redondance génétique au sein de la grande famille des gènes de type RALF. Néanmoins, les peptides RALFs apparaissent comme d’importants régulateurs lors de la reproduction chez Solanum chacoense et Arabidopsis thaliana.In angiosperms, reproduction occurs through double fertilization. The pollen tube delivers two sperm cells into the female gametophyte. A first sperm cell fertilizes the egg cell to produce a zygote, while the other fertilizes the central cell to produce the endosperm. To ensure reproductive success, the development of the female gametophyte within the ovule must establish a cellular pattern allowing interaction with the pollen tube and sperm cells. To this end, a dialogue must be established amongst the various cells of the ovule during its development, as well as during fertilization. Several types of communication are suggested by the analysis of developmental mutants. These communications must persist in the zygote and endosperm to allow the formation of a viable embryo within the seed. Recent developments have helped to find signaling molecules that support cell interaction models developed by the scientific community, but the signaling pathways are far from complete. In order to characterise genes encoding signaling proteins which are potentially active during reproduction in Solanum chacoense, I undertook the expression analysis of the RALF-like genes present in a bank of ESTs (Expressed Sequence Tags) specific to the ovule after fertilization. RALF, Rapid Alcalinization Factor, is a 5 kDa peptide that is part of the superfamily of Cysteine Rich Proteins (CRPs), which play a wide variety physiological roles within the plant. This expression analysis led to a detailed analysis of ScRALF3, whose expression in the plant is largely restricted to the ovule. The analysis of ScRALF3 RNAi transgenic plants revealed a function during megagametogenesis. The transgenic plants exhibit abnormal mitotic divisions that prevent the maturity of the embryo sac. The positioning of the nuclei, as well as the timing of divisions in the syncytium, appear to be responsible for the arrest of development during megagametogenesis. Isolation of the promoter as well as more accurate analysis of transcript expression reveals localisation within the ovule sporophytic tissue. The auxin signaling pathway is also involved in the regulation of ScRALF3 expression. ScRALF3 is a secreted peptide passing via the endoplasmic reticulum and the Golgi apparatus. In summary, ScRALF3 may be an important factor facilitating communication between the gametophyte and the sporophyte to allow maturation of the embryo sac. The identification of a potential orthologue in Arabidopsis thaliana led to the characterisation of AtRALF34. The lack of a phenotype during embryo sac development, however, suggests that genetic redundancy within the family of RALF-like genes is very complex. Nevertheless, the RALF peptides appear to be important regulators during reproduction in Solanum chacoense and Arabidopsis thaliana.