Thèses : « Synthetic plants »

1

Runguphan, Weerawat. « Reprogramming alkaloid biosynthesis in Catharanthus roseus : synthetic biology in plants ». Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/65274.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2011.
Vita. Cataloged from PDF version of thesis.
Includes bibliographical references.
The medicinal plant Madagascar periwinkle (Catharanthus roseus) produces over 130 monoterpene indole alkaloid (MIA) natural products. Many of these compounds have pharmaceutical value, such as the anticancer agents vinblastine and vincristine. Unnatural modifications can impart novel bioactivity to the parent natural product. Advances in synthetic biology and microbial engineering have allowed overproduction of natural products and their analogs in non-native organisms such as yeast and E. coli. However, re-engineering of plant pathways to yield "novel" products has been limited, particularly when compared to the successes achieved in prokaryotic systems. This thesis describes several strategies to re-engineer MIA biosynthesis in periwinkle to produce novel alkaloids. The first strategy involves the introduction of a biosynthetic enzyme with redesigned substrate specificity into periwinkle. The resulting transgenic plant culture produces a variety of unnatural alkaloid compounds when co-cultured with precursors that the re-engineered enzyme has been designed to accept. The second strategy improves upon this work by enabling periwinkle to autonomously synthesize precursor analogs in situ. Specifically, the prokaryotic halogenation machinery was introduced into the genome of periwinkle, which lacks the biosynthetic ability to produce halogenated compounds. These halogenases function within the context of the plant cell to generate halogenated precursor, which is then shuttled into MIA metabolism to yield halogenated alkaloids. Altogether, a new functional group-an organohalide-was introduced into plant secondary metabolism in a regioselective and predictable manner. The third strategy involves RNAi-mediated suppression of MIA biosynthesis in periwinkle. Alkaloid production was obliterated in the resulting transgenic plant culture. The silenced plant culture produces a variety of fluorinated alkaloids when co-cultured with fluorinated starting substrate. The yields of some unnatural alkaloids were improved since the natural precursor was absent. Finally, the fourth strategy describes chemical functionalization of halogenated MIAs. Postbiosynthetic chemical derivatizations of halogenated MIAs using palladium-catalyzed Suzuki-Miyaura cross-coupling reactions robustly afforded aryl and heteroaryl analogs of MIAs. Altogether, the work described in this thesis demonstrates the versatility of medicinal plants in the generation of unnatural alkaloids. Thus, despite their genetic complexity, plants are a viable platform for synthetic biology efforts.
by Weerawat Runguphan.
Ph.D.

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Nworji, Ogechukwu Frances. « Characterisation of transgenic tobacco plants expressing synthetic mouse prion protein ». Thesis, University of East London, 2016. http://roar.uel.ac.uk/5838/.

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The cellular prion protein (PrPC) is a glycoprotein with unknown function constitutively expressed in mammalian neurons. PrPC converts to a pathogenic misfolded isomer (PrPSc) through a poorly understood process, resulting in a group of fatal neurodegenerative diseases collectively known as transmissible spongiform encephalopathy or prion disease. Elucidating the molecular mechanisms behind prion conversion requires production of PrPC in recombinant systems. This study was designed to generate transgenic tobacco plants expressing recombinant mouse prion protein (mPrP). Using a synthetic gene encoding the mouse prion protein, plant expression vectors were constructed for constitutive mPrP expression in the apoplast (pGreen35SmPrP-Apo), cytosol (pGreen35SmPrP-Cyto) and endoplasmic reticulum (pGreen35SmPrP-ER). Putative transgenic plants transformed with either pGreen35SmPrP-Cyto or pGreen35SmPrP-ER were analysed by PCR, ELISA and immunoblot for transgene integration and expression. However, no viable plants were obtained from the pGreen35SmPrP-Apo transformants. ELISA analysis showed that recombinant mPrP accumulated up to 0.0024% of total soluble leaf protein in transgenic tobacco leaves transformed with the pGreen35SmPrP-Cyto construct and 0.0016% of total soluble leaf protein in plants designed to sequester recombinant mPrP to the ER. Furthermore, immunoblot analysis showed that ER-targeted recombinant mPrP was mainly unglycosylated, although a glycosylated mPrP isoform was observed indicating that transgenic tobacco plants process ER-targeted recombinant mPrP in a manner analogous to mammalian systems. The nutrient composition of several transgenic plants were analysed to determine the phenotypic effect of expressing recombinant mPrP in tobacco plants. The analysis revealed that transgenic lines expressing cytosolic-mPrP had elevated average levels of Mn2+ and Fe2+. In addition, kanamycin-treated transgenic plants expressing cytosolic-mPrP developed a non-rooting phenotype. Conversely, the average Cu2+ level was increased in analysed transgenic plants designed to sequester recombinant mPrP in the ER. Furthermore, the plants developed no visible phenotype upon kanamycin treatment. This result support studies that suggest that the PrPC has functional role in metal homeostasis and loss of its thermodynamic structure leads to metal dyshomeostasis which in turn has been linked to prion disease associated neurotoxicity. Finally, the recombinant mPrP was purified via affinity chromatography facilitated by the presence of a C-terminal polyhistidine tag on the synthetic gene constructs.

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Ko, Yuen-yi, et 高婉儀. « Synthetic studies of (-)-curcumol and its related natural products ». Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B31245420.

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Boehm, Christian Reiner. « Gene expression control for synthetic patterning of bacterial populations and plants ». Thesis, University of Cambridge, 2017. https://www.repository.cam.ac.uk/handle/1810/267842.

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The development of shape in multicellular organisms has intrigued human minds for millenia. Empowered by modern genetic techniques, molecular biologists are now striving to not only dissect developmental processes, but to exploit their modularity for the design of custom living systems used in bioproduction, remediation, and regenerative medicine. Currently, our capacity to harness this potential is fundamentally limited by a lack of spatiotemporal control over gene expression in multicellular systems. While several synthetic genetic circuits for control of multicellular patterning have been reported, hierarchical induction of gene expression domains has received little attention from synthetic biologists, despite its fundamental role in biological self-organization. In this thesis, I introduce the first synthetic genetic system implementing population-based AND logic for programmed hierarchical patterning of bacterial populations of Escherichia coli, and address fundamental prerequisites for implementation of an analogous genetic circuit into the emergent multicellular plant model Marchantia polymorpha. In both model systems, I explore the use of bacteriophage T7 RNA polymerase as a gene expression engine to control synthetic patterning across populations of cells. In E. coli, I developed a ratiometric assay of bacteriophage T7 RNA polymerase activity, which I used to systematically characterize different intact and split enzyme variants. I utilized the best-performing variant to build a three-color patterning system responsive to two different homoserine lactones. I validated the AND gate-like behavior of this system both in cell suspension and in surface culture. Then, I used the synthetic circuit in a membrane-based spatial assay to demonstrate programmed hierarchical patterning of gene expression across bacterial populations. To prepare the adaption of bacteriophage T7 RNA polymerase-driven synthetic patterning from the prokaryote E. coli to the eukaryote M. polymorpha, I developed a toolbox of genetic elements for spatial gene expression control in the liverwort: I analyzed codon usage across the transcriptome of M. polymorpha, and used insights gained to design codon-optimized fluorescent reporters successfully expressed from its nuclear and chloroplast genomes. For targeting of bacteriophage T7 RNA polymerase to these cellular compartments, I functionally validated nuclear localization signals and chloroplast transit peptides. For spatiotemporal control of bacteriophage T7 RNA polymerase in M. polymorpha, I characterized spatially restricted and inducible promoters. For facilitated posttranscriptional processing of target transcripts, I functionally validated viral enhancer sequences in M. polymorpha. Taking advantage of this genetic toolbox, I introduced inducible nuclear-targeted bacteriophage T7 RNA polymerase into M. polymorpha. I showed implementation of the bacteriophage T7 RNA polymerase/PT7 expression system accompanied by hypermethylation of its target nuclear transgene. My observations suggest operation of efficient epigenetic gene silencing in M. polymorpha, and guide future efforts in chassis engineering of this multicellular plant model. Furthermore, my results encourage utilization of spatiotemporally controlled bacteriophage T7 RNA polymerase as a targeted silencing system for functional genomic studies and morphogenetic engineering in the liverwort. Taken together, the work presented enhances our capacity for spatiotemporal gene expression control in bacterial populations and plants, facilitating future efforts in synthetic morphogenesis for applications in synthetic biology and metabolic engineering.

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Pollak, Williamson Bernardo. « Frameworks for reprogramming early diverging land plants ». Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/273535.

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Plant form is a product of emergent processes of cell division, patterning and morphogenesis. These fundamental processes remain poorly characterised in plants. However, engineering approaches can provide new tools and frameworks for the study and manipulation of plant development. This dissertation describes the development of engineering frameworks for reprogramming of the early diverging land plant Marchantia polymorpha (Marchantia). I describe the generation of genomic and transcriptomic datasets for Marchantia, which has provided the basis for the compilation of a gene-centric registry of DNA parts for engineering (MarpoDB). I describe the development of Loop assembly, an efficient and standardised DNA assembly system based on Type IIS restriction enzymes for recursive fabrication of DNA circuits with high efficiency. MarpoDB was used to mine new DNA parts compatible with Loop assembly which were used to generate plant transformation vectors for labelling of cellular features to study aspects of growth and development. I performed image analysis of genetic markers for segmentation and quantification of cellular properties in germinating gemmae. I implemented high-efficiency Cas9-mediated mutagenesis in Marchantia for use in functional molecular genetics studies. Furthermore, I produced inducible systems for expression of heterologous elements by transactivation which showed negligible levels of basal activity. It was possible to use this system for induction of gene expression in single cells. Finally, these new frameworks were applied to study the gametophytic meristem in Marchantia gemmae. I mapped the expression of several putative candidate homologues for higher plant meristem regulators, performed overexpression and loss-of-function studies for homologues of WUSCHEL, CLAVATA3 and SHOOT MERISTEMLESS. A strategy for misregulation of endogenous genes was developed using inducible transactivation, and was used with cellular markers for WUSCHEL and CLAVATA3 homologues in Marchantia.

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Cowin, Linda Marie. « Some stereochemical and synthetic studies in serrulatane diterpenoid chemistry / ». Title page, contents and abstract only, 1992. http://web4.library.adelaide.edu.au/theses/09PH/09phc8737.pdf.

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Marsian, Johanna. « Transient expression of poliovirus-like particles in plants : developing a synthetic polio vaccine ». Thesis, University of East Anglia, 2016. https://ueaeprints.uea.ac.uk/62929/.

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Plants, or cell suspension cultures derived from them, are a promising platform for the production of biologics and pharmaceuticals. In this work transient expression utilising the pEAQ vector system was deployed for the expression of virus-like particles (VLPs) in Nicotiana benthamiana or N. tabacum BY-2 cell suspension cultures. The results presented in this thesis demonstrate the potential of plant systems for the production of VLP-based vaccines. VLPs of the fish virus, Nervous necrosis virus (NNV), were successfully produced in plants by transient expression of the coat protein. The protein self-assembled into T = 3 particles, which appeared to be morphologically identical to the wild-type NNV when analysed by high resolution microscopy but were devoid of nucleic acid. In addition, transgenic BY-2 cell suspension lines were generated expressing correctly assembled NNV VLPs. Poliovirus (PV)-like particles from all three PV serotypes, containing either the wt coat protein or coat proteins with stabilising mutations, were successfully expressed in plants. These were generated by co-expression of the structural polyprotein P1 and the proteinase 3CD. Sufficient quantities of purified particles could be obtained for structural and immunological analysis. Mice carrying the gene for the human PV receptor were protected from wild-type PV when immunised with the plant-made stabilised PV VLPs. Structural analysis of the stabilised mutant of PV3 at 3.6 Å resolution revealed a structure almost indistinguishable from wild-type PV3, with the stabilising mutations having no effective on the antigenic surface of the particle. To make the product more attractive to the vaccine industry, tobacco BY-2 cells have been successfully tested for the transient expression of the above-mentioned PV mutant VLPs using the cell-pack method.

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Mbaebie, Oyedemi B. O. « Antiplasmid and antimicrobial activities of synthetic and natural products from selected medicinal plants ». Thesis, University College London (University of London), 2015. http://discovery.ucl.ac.uk/1468641/.

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This PhD thesis is part of ongoing project to identify plant natural products and selected synthetic compounds that possess antimicrobial properties; and are able to promote plasmid loss or interfere with bacterial conjugation. The conjugative broad host plasmids investigated include PKM101 (Inc N), TP114 (Inc I2), PUB307 (Inc P), and low- copy number plasmids: R6K (Inc X), R7K (Inc W) and R1-drd-19 (Inc F11). They represented the incompatibility plasmid groups that are currently associated with gross dissemination of antibiotic resistance in bacteria. A series of plant extracts evaluated at sub-inhibitory concentration of 100 mg/L, were shown to inhibit bacterial plasmid conjugation and their active constituents were isolated and characterised. Mallotus philippinensis yielded rottlerin and red compound, with good to moderate antibacterial activity against multidrug resistant Staphylococcus aureus strains, and had a broad range inhibition against the resistant plasmids. Investigation of extracts from the resin of Cannabis sativa L. identified tetrahydrocannabinolic acid (THCA) and cannabinolic acid (CBNA) which in addition to two synthetic cannabinoids: cannabigerol and olivetol inhibited the conjugal transfer of TP114 between E. coli strains. The antiplasmid activities of Δ9-THC, CBN, CBD, significantly reduced the transfer of amoxicillin–resistance conferring PKM 101. Methanolic extract from the dried fruits of Evodia rutaecarpa yielded evodiamine, rutaecarpine and naturally-isolated sucrose. Rutaecarpine was the most active alkaloid against NorA-expressing SA1199B and XU212 strain expressing TetK efflux mechanism. Evodiamine and sucrose had lesser antibacterial effect as well as low level of inhibition against the plasmids. Rutaecarpine and evocarpine remarkably reduced the transfer frequency of PKM 101, showing a high 2 level effect of inhibition by the compound. The bioassay-guided analysis of Capsicum annuum L. yielded capsaicin and dihydrocapsaicin (DHC) which demonstrated moderate antibacterial activities but inhibited conjugal transfer of R-plasmids actively. Capsaicin exhibited a broad range antiplasmid activity while DHC showed selective inhibition. The effect of synthetic compounds that were assessed: ferulenol, 6-gingerol and 6-shogoal were twice as effective against the transfer of PKM 101, TP114 and PUB307 compared to capsaicin, while nonivamide had no remarkable activity. With the exception of promethazine, capsaicin and dihydrocapsaicin that showed some interaction with DNA due to decreased fluorescence which suggests binding, the rest of the compounds: rottlerin, red compound, ferulenol, evocarpine, rutaecarpine, 6-gingerol, 6-shogaol and nonivamide did not bind to DNA. This may indicate other probable mechanism of antiplasmid action of the compounds. Together, some of these compounds were notable for their dual properties: robust antistaphylococcal activity and a broad host range antiplasmid effect, and are reported for the very first time. Such potentials are valuable in the discovery of next generation antimicrobial drugs.

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Tanner, T. M. « An investigation of the interactions of the androgen receptor with a non-steroidal compound and two synthetic progestins ». Thesis, Stellenbosch : Stellenbosch University, 2002. http://hdl.handle.net/10019.1/52683.

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Thesis (MSc)--Stellenbosch University, 2002.
ENGLISH ABSTRACT: The aim of this thesis was to define the interactions of the androgen receptor (AR) with an analog of a non-steroidal plant compound, Compound A (CpdA), as well as two synthetic progestins, medroxyprogesterone acetate (MPA) and norethindrone acetate (NET-A). The data presented indicates that CpdA has antiandrogenic properties, as it represses androgen-induced activation of both specific and non-specific androgen-responsive reporter constructs. It was found that CpdA exerts these effects by a mechanism other than competition with androgen for binding to the ligand-binding domain (LBD) of the receptor. On the other hand, it is demonstrated that both MPA and NET-A compete with androgen for binding to the AR and induce partial agonist activity via the receptor. Using mammalian two-hybrid assays it was revealed that CpdA, similar to anti-androgenic compounds that are able to compete with androgens for binding to the receptor, represses the androgen-induced interaction between the NH2- and COOH-terminals of the AR (N/C-interaction) without competing for binding to the LBD. Furthermore, it was shown that CpdA slightly represses the androgen-dependent recruitment of steroid receptor co-activator 1 (SRC1) to the activation function (AF2) domain of the AR. When the effects of MPA and NET-A on the N/C-interaction were studied, intriguing results were obtained. NET-A, as expected, induced this AR agonist-induced interaction. MPA, however, repressed this AR agonist-induced interaction, an effect previously associated with anti-androgenic activity, despite displaying partial agonist activity in transctivation experiments. On the other hand, both MPA and NET-A induced the interaction between SRC1 and the AF2 domain. In additional experiments with CpdA, it was found that CpdA did not affect the recruitment of SRC1 to the AF1 domain of the receptor; neither did it influence the constitutive activity of the NH2-terminal domain. The anti-androgenic activities of CpdA were confirmed by the toxic effect that this compound had on the androgen-dependent lymph node carcinoma of the prostate (LNCaP) cell-line as well as its ability to repress the androgen-induced expression of the prostate specific antigen (PSA) protein. Taken together, the results presented in this thesis, in combination with the knowledge available on AR function, contribute to an improved understanding of AR function. Furthermore, the importance of defining the precise mechanism by which individual compounds exert their effects is highlighted. In this regard it is demonstrated that two compounds (MPA and NET-A) that display partial agonist activity, can exert their effects via different mechanisms at the molecular level. Detecting such differences in the molecular mechanisms of action could facilitate the improved design of progestins as well as aid clinicians and their patients in selecting the best method of contraception. Lastly, the insights gained into the mechanisms of the anti-androgenic action of CpdA could be useful in therapeutic drug design for diseases, such as prostate cancer, that have an androgen-dependent etiology.
AFRIKAANSE OPSOMMING: Die doel van hierdie tesis was om die interaksies van die androgeen reseptor (AR) met ‘n analoog van ‘n nie-steroiediese plant verbinding, Verbinding A (VbgA), sowel as met twee sintetiese progestogene, medroksiprogesteroon asetaat (MPA) en noretiendroon asetaat (NET-A), te definieer. Die data verskaf dui daarop dat VbgA anti-androgeniese eienskappe besit deurdat dit androgeen-gei'nduseerde aktivering van beide spesifieke- en nie-spesifieke androgeen-responsiewe rapporteerderkonstrukte onderdruk. VbgA veroorsaak hierdie effekte deur ‘n meganisme wat nie kompetisie met androgeen vir binding aan die ligand-bindingsdomein (LBD) van die reseptor behels nie. In teenstelling hiermee word getoon dat beide MPA en NET-A kompeteer met androgeen vir binding aan die AR en gedeeltelike agonistiese aktiwiteit induseer via hierdie reseptor. Deur gebruik to maak van ‘n soogdier twee-hibried essai word getoon dat VbgA, soos ander anti-androgeniese verbindings wat kompeteer met androgeen vir binding aan die reseptor, die androgeen-gei'nduseerde interaksies tussen die NH2- en COOH-terminale van die AR (N/C-interaksie) onderdruk, sonder om te kompeteer vir binding aan die LBD. Daarby is dit bewys dat VbgA die androgeenafhanklike werwing van steroied reseptor ko-aktiveerde 1 (SRC1) na die aktiverings funksie (AF2) domein van die AR gedeeltelik onderdruk. Die studie van die effekte van MPA en NET-A op die N/C-interaksie het interessante resultate opgelewer. NETA, soos verwag, het hierdie AR agonis-gei'nduseerde interaksie geinduseer. MPA, aan die ander kant, het hierdie AR agonis-gei'nduseerde interaksie onderdruk, ‘n effek wat tevore met anti-androgeniese aktiwiteit geassosieer is, al het die transaktiveringseksperimente daarop gedui dat MPA ‘n AR agonis is. Aan die ander kant, het beide MPA en NET-A die interaksie tussen SRC1 en die AF2 domein geinduseer. In addisionele eksperimente met VbgA is gevind dat VbgA geen effek het op die werwing van SRC1 na die AF1 domein van die reseptor nie en ook geen invloed het op die konstitutiewe aktiwiteit van die NHh-terminaal domein nie. VbgA se antiandrogeniese eienskappe is bevestig deur die toksiese effekte op die androgeenafhanklike limfknoop karsinoom van die prostaat (LNCaP) sellyn sowel as deur sy vermoe om die androgen-gei'nduseerde uitdrukking van die prostaat spesifieke antigeen (PSA) protei'en te onderdruk. Die resultate aangebied in hierdie tesis, in kombinasie met die beskikbare kennis oor AR funksie, dra by tot ‘n verbeterde kennis van AR funksionering. Verder word die belang van die definiering van die meganisme waardeur individuele verbindings hulle effekte veroorsaak, getoon. In hierdie verband is getoon dat twee verbindings (MPA en NET-A), wat gedeeltelike agonistiese aktiwiteit besit, hulle effekte via verskillende meganismes op die molekulere vlak veroorsaak. Deur hierdie verskille in die molekulere meganismes van aksie uit te wys, kan beter progestogene ontwikkel word, en verder sal dit vir dokters en hul pasiente help om die beste voorbehoedmiddel te kies. Laastens, die insig wat verkry is ten opsigte van die meganismes van anti-androgeniese aktiwiteit van VbgA mag nuttig wees in die ontwerp van terapeutiese middels vir die behandeling van siektetoestande met androgeen-afhanklikke etiologie (bv. prostaatkanker).

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Brundin, Carl. « Alternative energy concepts for Swedish wastewater treatment plants to meet demands of a sustainable society ». Thesis, Umeå universitet, Institutionen för tillämpad fysik och elektronik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-146831.

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This report travels through multiple disciplines to seek innovative and sustainable energy solutions for wastewater treatment plants. The first subject is a report about increased global temperatures and an over-exploitation of natural resources that threatens ecosystems worldwide. The situation is urgent where the current trend is a 2°C increase of global temperatures already in 2040. Furthermore, the energy-land nexus becomes increasingly apparent where the world is going from a dependence on easily accessible fossil resources to renewables limited by land allocation. A direction of the required transition is suggested where all actors of the society must contribute to quickly construct a new carbon-neutral resource and energy system. Wastewater treatment is as required today as it is in the future, but it may move towards a more emphasized role where resource management and energy recovery will be increasingly important. This report is a master’s thesis in energy engineering with an ambition to provide some clues, with a focus on energy, to how wastewater treatment plants can be successfully integrated within the future society. A background check is conducted in the cross section between science, society, politics and wastewater treatment. Above this, a layer of technological insights is applied, from where accessible energy pathways can be identified and evaluated. A not so distant step for wastewater treatment plants would be to absorb surplus renewable electricity and store it in chemical storage mediums, since biogas is already commonly produced and many times also refined to vehicle fuel. Such extra steps could be excellent ways of improving the integration of wastewater treatment plants into the society. New and innovative electric grid-connected energy storage technologies are required when large synchronous electric generators are being replaced by ‘smaller’ wind turbines and solar cells which are intermittent (variable) by nature. A transition of the society requires energy storages, balancing of electric grids, waste-resource utilization, energy efficiency measures etcetera… This interdisciplinary approach aims to identify relevant energy technologies for wastewater treatment plants that could represent decisive steps towards sustainability.

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Wood, Barry Alan. « Synthetic and analytical studies of phytochelations, the metal(loid)-binding peptides of terrestrial plants ». Thesis, University of Aberdeen, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.540437.

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This thesis describes research based around phytochelatins (PCs), plant peptides synthesised during the influx of metal(loid)s such as arsenic. Development of synthetic strategies for production of PCs and a bromine-based thiol tag were pursued. The role of PCs in the arsenic translocation system in plants was monitored firstly by statistical analysis, then by monitoring arsenic translocation of L-BSO-poisoned and mutant plants. Whilst protected PC₂ was synthesised in good yield, subsequent isolation of deprotected PC₂ was not achieved via SEC or RP chromatography. Statistical analysis showed that differential transport of iAs(V) and DMA(V) in planta between two plant groups was not due to PC/As(III)-PC speciation difference, but this was far from conclusive. Plants exposed to iAs(V) and the PC synthase inhibitor L-BSO showed increased arsenic translocation with decreasing As(III)-PC levels, but the trend was not statistically significant. Analysis of Arabidopsis thaliana mutants with differing PC levels confirmed that arsenic translocation increased with reduced PC and As(III)-PC complex levels. HR-ICP-MS quantified unbound PC species on m/z 32 (S⁺), whilst HR-ESI-MS identified the (GS)₃-As(III) complex for the first time in vivo. Whilst significant levels of iAs(III) and PC₂ exist within seaweeds, no As(III)-PC complex formation was observed. This indicates a transient role, if any, for PCs during the in vivo detoxification of arsenic within seaweeds. The development of a thiol tag based upon a polybrominated-pyrrole moiety was unsuccessful, owing to the greater-than-anticipated complexity of the chemistry exhibited by pyrrole.

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Perera, Mallawa Thanthrie Mudiyanselage D. Renuka. « Response of pests of brassicae and their parasitoids to synthetic and natural feeding deterrents ». Thesis, University of Aberdeen, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287701.

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Antifeedants and growth regulators have potential as alternatives to conventional methods of insect pest control. As with conventional chemicals it is important to consider their effects on natural enemies of the pests. The aim of this project was to determine whether the bitter-tasting synthetic chemical denatonium benzoate as an antifeedant and compare with neem derivatives. Other aims were to investigate their effect on parasitoids and the field infestation of cabbage pests. Denatonium benzoate is systemic and had no contact effect but acted as an antifeedant on a generalist sap feeder Myzus persicae and reduced the survival, fecundity, and lifespan. Neem derivatives, Azatin EC and Pestistat R were more effective of which Azatin EC was the most effective. Antifeedants further reduced the fecundity and survival when parasitized with its parasitoid, Aphidius matricariae and neem derivatives had adverse effects on both aphid and the parasitoid. Denatonium benzoate and Pestistat R with a specialist leaf feeder, Pieris brassicae and all antifeedants with Plutella xylostella (generalist leaf feeder) and Chrysodeixis eriosoma (specialist brassica leaf feeder) reduced the leaf area consumed and it was inversely proportional to the concentration. The highest leaf area consumption was in denatonium benzoate and the lowest in Pestistat R. Higher azadirachtin concentrations were detrimental but denatonium benzoate was safer to the larval parasitoid, Cotesia plutellae. Denatonium benzoate and Azatin EC reduced field infestation of M. persicae, P. xylostella and C. eriosoma in Peradeniya, Sri Lanka and Azatin EC was the most effective. Denatonium benzoate acts as an antifeedant against cabbage pests and safer towards parasitoids hence can be used in integrated pest management programmes. Neem derivatives are comparatively more effective on pests but harmful to parasitoids. Denatonium benzoate and Azatin EC effectively reduced the pest infestation under field conditions.

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Xin, Mei. « Interaction of atmospheric elemental mercury with natural, synthetic, and anthropogenically derived substrates ». abstract and full text PDF (free order & ; download UNR users only), 2007. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3289450.

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Sarrión, Perdigones Manuel Alejandro. « Design and development of modular DNA assembly tools for Multigene Engineering and Synthetic Biology in Plants ». Doctoral thesis, Universitat Politècnica de València, 2014. http://hdl.handle.net/10251/35399.

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The post-genomics era has put at the disposal of modern plant breeders an endless list of genetic building blocks for the design of new biotechnological crops. After a first wave of single-gene transgenic with controversial public acceptance, genomic information and technology is paving the way for increasingly complex designs based in multiple gene engineering. Those designs aiming at the production of inexpensive health-promoting compounds are most likely to be welcomed by consumers. In this project we plan to develop new multigene assembling tools. During this PhD, a standardized collection of interchangeable genetic parts (including promoters, CDS, P-DNAs, etc) and vectors will be developed. The collection, inspired in Synthetic Biology standards, will be made easy-to-assemble in an interchangeable, semi-idempotent and seamless fashion by the addition of flanking recognition sites of type IIS Restriction endonucleases. The construction of the collection will facilitate multigene engineering and will constitute a first step towards enabling Synthetic Biology in plants.
Sarrión Perdigones, MA. (2014). Design and development of modular DNA assembly tools for Multigene Engineering and Synthetic Biology in Plants [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/35399
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Anghilante, Régis. « Flexibilisation and integration of solid oxide electrolysis units in power to synthetic natural gas plants ». Thesis, Toulouse, INPT, 2020. http://www.theses.fr/2020INPT0094.

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La technologie d’électrolyse à oxydes solides (SOE) pourrait permettre d’améliorer l’efficacité des installations de conversion d’électricité en gaz naturel de synthèse (SNG) et de réduire leur coût, grâce à une integration thermique performante, à l’industrialisation de la technologie et une flexibilisation des unités pour la pénétration de l’électricité renouvelable. Une analyse énergétique détaillée de trois concepts d’installations power-to-SNG innovants est d’abord réalisée avec une intégration thermique détailllée. Les installations intégrant des unités SOE et produisant du GNC ou du GNL présentent des rendements d’au moins 78,5% sur base PCS, bien plus élevés que pour les installations intégrant des unités d’électrolyse PEM qui produisent du GNC avec un rendement de 64,4%. La réponse thermique des unités SOE soumises à des variations de charge électrique est ensuite étudiée sur la base d’un modèle dynamique 1D à l’échelle d’une cellule (SOEC). Les cellules « électrolyte support » sont thermiquement plus stables que les « électrode support » et donc plus adaptées à des charges électriques variables. Le modèle est ensuite étendu à une unité entière de production et de stockage d’H2 et couplé à différents profils électriques. L’unité affiche une consommation énergétique de 3,4-3,8 kWh·Nm-3 H2 et un rendement élevé de l’électricité vers l’H2 (93-103%) par récupération de la vapeur de méthanation. Un dimensionnement du réservoir d’H2 et de l’unité de méthanation est réalisé avec un profil électrique éolien. Les charges électriques variables réduisent l’efficacité des installations power-to-SNG, en augmentent les coûts et en complexifient l’opération. Les installations multifuels semblent être l’option la plus prometteuse pour gérer l’intermittence de la production d’électricité. Etendre la gamme d’opération des SOECs aux modes exotherme et endotherme améliorerait les rendements de l’électricité vers l’H2 en comparaison au mode marche/arrêt. Pour une charge électrique constante, les SOECs doivent préférablement être opérées au thermoneutre ou en mode exotherme. Enfin, les coûts de production du SNG sont évalués, en commençant par une estimation ascendante des coûts d’investissement d’unités SOE. Les coûts de production du SNG des concepts étudiés vont de 82 à 89 €·MWh-1 CH4 (PCS) avec des unités SOE, valeurs plus faibles que pour des unités PEM, mais qui restent deux fois supérieures au prix moyen du gaz naturel en France
The solid oxide electrolysis technology (SOE) could improve the conversion efficiency of power-tosynthetic natural gas (SNG) plants and reduce their costs, provided that i) a performant thermal integration is implemented ii) the technology is implemented at industrial scale, and iii) plants can absorb the intermittency of renewable power sources. First, the energy analysis of three innovative power-to-SNG plant concepts is implemented. For each concept, a full explicit thermal integration is proposed. Plants with integrated SOE units show efficiencies higher than 78.5% (based on the HHV of the SNG) for the production of CNG and LNG, significantly higher than plants with PEM units with a 64.4% efficiency for CNG production. Second, the thermal response of SOE units to electrical power loads is investigated with a 1D dynamic model at the cell level (SOEC). Electrolyte support cells present a higher thermal stability than electrode support cells and should be preferred for fluctuating power applications. The model was then extended to a full H2 production and storage unit and coupled with different electrical power profiles. The units shows an energy consumption of 3.4-3.8 kWh·Nm-3 H2 and a high power-to-H2 conversion efficiency (93-103%) because of the steam recovery from the methanation unit. A first dimensioning of the H2 storage tank and the methanation unit is proposed, assuming a windmill power profile. Fluctuating power profiles reduce the efficiency of power-to-SNG plants, increase their costs and complexify their operation. Multifuel plants seem to be the most promising option to tackle the issue of intermittent power production. Extending the operation range of SOECs to exothermic and endothermic modes would improve power-to-H2 conversion efficiencies compared to on/off operation. In case of constant power load though, SOECs should preferably be operated at the thermoneutral point or in exothermic mode. Third, SNG production costs corresponding to the aforementioned plant concepts are evaluated, starting with a bottom-up cost evaluation of SOE units. The SNG production costs are in the range of 82-89 €·MWh-1 CH4 (HHV) with SOE units, which is lower than with PEM units, but remains two times higher than the average price of conventional natural gas for all sectors in France

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Weldegebriel, Kibrom Asmerom. « Synthetic studies on the spiroacetal moiety of Stenocarpin, a metabolite of Diplodia maydis / ». Diss., Access to E-Thesis, 2003. http://upetd.up.ac.za/thesis/available/etd-09082005-122736/.

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Juárez, Ortega Paloma. « Production of recombinant Immunoglobulin A in plants for passive immunotherapy ». Doctoral thesis, Universitat Politècnica de València, 2014. http://hdl.handle.net/10251/37015.

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Mucosal passive immunization is the transfer of active antibodies from one organism to the mucosal surfaces of another organism for preventing or treating infectious diseases. Mucosal passive immunization has a great potential for the prevention and treatment of enteric infections like Rotavirus, which causes more than 114 million episodes of diarrhoea annually with a death toll of more than 450.000 per year. However, the high cost of recombinant antibodies with the current manufacturing systems based on mammalian cells hampers the production of the high antibody quantities required for passive immunization strategies. Alternative expression platforms such as plants could provide higher scalability and reduced costs. Moreover, the use of edible plant organs, which are Generally¿Regarded¿As¿ Safe (GRAS), could reduce manufacturing costs even further by easing the requirements for antibody purification. We analyze here the feasibility of utilizing fruits as inexpensive biofactories of human antibodies that can be orally delivered as crude extracts or partially purified formulations in mucosal passive immunization strategies. In the first section of this thesis, the construction of tomato plants producing a model human Immunoglobulin A (IgA) against rotavirus in their fruits is described. As a result, an elite homozygous line was obtained whose fruits produced on average 41 ¿g of IgA per gram of fresh weigh, equivalent to 0.69 mg IgA per gram of dry tomato powder. Minimally processed products derived from IgA¿expressing tomatoes were shown to strongly inhibit virus infection in an in vitro neutralization assay. Moreover, in order to make IgA¿expressing tomatoes easily distinguishable from wild¿type tomatoes, they were sexually crossed with a transgenic tomato line expressing the genes encoding Antirrhinum majus Rosea1 and Delila transcription factors, which confer purple colour to the fruit. The resulting transgenically¿labelled purple tomatoes contained not only high levels of recombinant neutralizing human IgA but also increased amounts of anthocyanins. In the second section of the thesis the composition of IgA¿expressing tomatoes was analyzed in search of possible unintended effects that could compromise the GRAS status of the final product. To this end, transgenic IgA¿tomatoes were compared with wild type tomatoes and also commercial tomato varieties using proteomic and metabolomic approaches. 2D¿DIGE gels coupled with LC¿MSMS for protein identification showed that all the uptrend differential proteins detected corresponded only to immunoglobulin chains or antibody fragments. On the other hand, non¿targeted metabolite data obtained by UPLC¿MS
Juárez Ortega, P. (2014). Production of recombinant Immunoglobulin A in plants for passive immunotherapy [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/37015
TESIS

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Bircher, Sam. « Phytoremediation of natural and synthetic steroid growth promoters used in livestock production by riparian buffer zone plants ». Thesis, University of Iowa, 2011. https://ir.uiowa.edu/etd/2675.

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Prasad, Anjali Km. « Food utilization efficiencies and developmental traits of common tea loopers (Geometridae:Lepidoptera) on natural host plants and synthetic diets ». Thesis, University of North Bengal, 2016. http://hdl.handle.net/123456789/2554.

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Nyamhingura, Amon. « Characterization and chemical speciation modelling of saline effluents at Sasol Synthetic Fuels Complex-Secunda and Tukuta power station ». Thesis, University of the Western Cape, 2009. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_7974_1297940655.

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The study shows conclusively that brine composition and concentration is highly variable at these South African power utilities and processes such as RO, contact with ash and CO2 ingress can have an impact upon the overall brine quality. Aq.QA was found to be a more accurate tool for classifying waters according to dominant ions than Stiff diagrams but Stiff diagrams still have the superior advantage of being a mapping tool to easily identify samples of similar composition as well as quickly identify what has been added or what has been removed from a water stream. Chemical speciation could identify effluent streams where CO2 dissolution had taken place.

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Medel, Vera Carlos Pablo. « Seismic probabilistic safety assessment and risk control of nuclear power plants in Northwest Europe ». Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/seismic-probabilistic-safety-assessment-and-risk-control-of-nuclear-power-plants-in-northwest-europe(c51a155a-289b-40c0-a642-644cb527939b).html.

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Nuclear power plays a crucial role in energy supply in the world: around 15% of the electricity generated worldwide is provided from nuclear stations avoiding around 2.5 billion tonnes of CO2 emissions. As of January 2016, 442 reactors that generated 380+ GW were in operation and 66 new reactors were under construction. The seismic design of new nuclear power plants (NPPs) has gained much interest after the high-profile Fukushima Dai-ichi accident. In the UK, a tectonically stable continental region that possesses medium-to-low seismic activity, strong earthquakes capable of jeopardising the structural integrity of NPPs, although infrequent, can still occur. Despite that no NPP has been built in Great Britain after 1995, a New Build Programme intended to build 16 GW of new nuclear capacity by 2030 is currently under way. This PhD project provides a state-of-the-art framework for seismic probabilistic safety assessment and risk control of NPPs in Northwest Europe with particular application to the British Isles. It includes three progressive levels: (i) seismic input, (ii) seismic risk analysis, and (iii) seismic risk control. For seismic input, a suitable model to rationally define inputs in the context of risk assessments is proposed. Such a model is based on the stochastic simulation of accelerograms that are compatible with seismic scenarios defined by magnitude 4 < Mw < 6.5, epicentral distance 10 km < Repi < 100 km, and different types of soil (rock, stiff soil and soft soil). It was found to be a rational approach that streamlines the simulation of accelerograms to conduct nonlinear dynamic analyses for safety assessments. The model is a function of a few variables customarily known in structural engineering projects. In terms of PGA, PGV and spectral accelerations, the simulated accelerograms were validated by GMPEs calibrated for the UK, Europe and the Middle East, and other stable continental regions. For seismic risk analysis, a straightforward and logical approach to probabilistically assess the risk of NPPs based on the stochastic simulation of accelerograms is studied. It effectively simplifies traditional approaches: for seismic inputs, it avoids the use of selecting/scaling procedures and GMPEs; for structural outputs, it does not use Monte Carlo algorithms to simulate the damage state. However, it demands more expensive computational resources as a large number of nonlinear dynamic analyses are needed. For seismic risk control, strategies to control the risk using seismic protection systems are analysed. This is based on recent experience reported elsewhere of seismically protected nuclear reactor buildings in other areas of medium-to-low seismic activity. Finally, a scenario-based incremental dynamic analysis (IDA) is proposed aimed at the generation of surfaces for unacceptable performance of NPPs as function of earthquake magnitude and distance. It was found that viscous-based devices are more efficient than hysteretic-based devices in controlling the seismic risk of NPPs in the UK. Finally, using the proposed scenario-based IDA, it was found that when considering all controlling scenarios for a representative UK nuclear site, the risk is significantly reduced ranging from 3 to 5 orders of magnitude when using viscous-based devices.

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Gupta, Rahul. « PCR-based Synthesis of Codon Optimized cry2Aa Gene for Production of Shoot and Fruit Borer (Leucinodes orbonalis) Resistant Eggplant (Solanum melongena L.) Cultivars ». Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/36369.

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Brinjal shoot and fruit borer (Leucinodes orbonalis Guenee) is a major limiting factor in commercial cultivation of eggplant in southeast Asia. Extensive use of pesticides as well as the conventional breeding methods have been ineffective in controlling the borer so there is a need for Integrated Pest Management (IPM) strategies for its control. Bacillus thuringiensis (Bt) is known to produce a variety of insecticidal crystal proteins toxic to lepidopteran, dipteran and coleopteran pests. The Cry2Aa protein has been found to be more toxic to brinjal shoot and fruit borer than Cry1Ab. My objective was to develop eggplant cultivars that express a codon-optimized cry2Aa gene, the sequence of which is based on that of an Indian isolate of Bt, with the eventual goal of producing fully resistant cultivars. The cry2Aa gene was modified for optimal expression in eggplant using the codon usage frequencies based on solanaceous sequences (eggplant, tomato and pepper). The GC content was increased from 34.3% in the native gene to 41.3% in the optimized gene, thus removing the AT-rich regions that are typical for Bt cry genes. Also, other mRNA destabilizing and hairpin forming structure sequences were removed. The gene was synthesized in four different parts with complementary restriction sites. A total of 152 oligonucleotides (oligos) was used to assemble the 1.9 kb gene using dual asymmetric (DA) and overlap extension (OE) PCR techniques. The individual parts were subsequently ligated using the complementary restriction sites and inserted into vector pCAMBIA 1302. Also, the transformation efficiency of 12 different eggplant cultivars was tested using plasmid pHB2892 to predict utility for transformation with the synthetic cry2Aa.
Master of Science

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Ramos, Oscar F. « Response of wheat plants (Triticum aestivum L) to stress and synthetic elicitors of systemic acquired resistance as expressed by phenolic levels in foliage and mature grain ». Diss., Kansas State University, 2016. http://hdl.handle.net/2097/32922.

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Doctor of Philosophy
Department of Grain Science and Industry
Ronald L. Madl
Praveen Vadlani
Producers of whole wheat products are interested in marketing the health-promoting benefits of wheat antioxidants. However, they need a steady crop supply with consistent levels of antioxidants. The variable phenolic content in wheat crops is a problem. The objectives of this research were to 1) identify the factor (s) that contribute the most to the variability in phenolic content, 2) understand the mechanism (s) responsible for phenolic synthesis, and 3) artificially trigger that mechanism (s). Phenolics are hypothesized to be part of the defense response of hard red winter wheat (Triticum aestivum L) to stress. The effect of insect feeding, pathogen infection, and heat stress on phenolics in grains from wheat plants cv. Karl 92 was evaluated. Bird-cherry oat aphid (Rhopalosiphum padi) feeding stress significantly explained the variation in phenolic content. Furthermore, the relative allocation of carbon resources to grain yield/phenolic content was influenced by the stage of the plant at which aphid feeding started to occur. Based on these findings, phenolics were hypothesized to be an active defense response acting through a mechanism known as systemic acquired resistance (SAR). In order to prove this hypothesis, several synthetic elicitors of SAR were tested for their effectiveness at inducing de novo phenolic synthesis in wheat foliage and in mature grains. Elicitors that acted through the salicylic- and jasmonic acid signaling pathways were effective at inducing phenolic synthesis by 49% and 177%, respectively, in the leaves 36 hours post spray application. They also elicited a phenolic response in mature grains of up to 21% induction. Enhancement of the levels of naturally occurring phenolic compounds with antioxidant activity in wheat grains through SAR activation is a value addition strategy that can potentially increase the profitability of hard red winter wheat crops. It can also provide manufacturers of whole wheat with natural antioxidants that can potentially be used to substitute their synthetic counterparts in wheat based products.

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Gully, Kay. « The plant immune system : induction, memory and de-priming of defense responses by endogenous, exogenous and synthetic elicitors ». Thesis, Angers, 2019. http://www.theses.fr/2019ANGE0001/document.

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En tant qu’organismes sessiles, les plantes doivent réagir rapidement et intensément, via des réponses défensives, pour repousser les pathogènes invasifs. Le système immunitaire des plantes peut être déclenché par des molécules élicitrices exogènes ou endogènes. Une autre classe d’éliciteurs, les éliciteurs synthétiques, contient également des composés promouvant une réponse défensive.Dans ce manuscrit, je décris la découverte et caractérisation d’une nouvelle famille de petits peptides endogènes potentiellement sécrétés(PROSCOOP), dont les membres incluent de petits peptides (SCOOP). Je démontre que les SCOOP sont impliqués dans les mécanismes de défense de la plante et le développement racinaire. Une variété de peptides SCOOP induit des réponses défensives de courtes et longues durées.De plus, des traitements avec le peptideSCOOP12 induisent une résistance à Pseudomonas syringae chez Arabidopsis.Dans la seconde partie de cette thèse, je démontre que le traitement des plantes avec un éliciteur synthétique peut mener à une mémoire transcriptionnelle à long terme, et que le challenge subséquent des plantes traitées par application d’un éliciteur exogène désactive cette mémoire transcriptionnelle. En conclusion, ma thèse présente (1) la diversité des fonctions que peuvent avoir ces éliciteurs et (2) l’impact sur les systèmes de défense de la plante et ses conséquences sur la mémoire et le développement de la plante
As sessile organism, plants have to react quickly and strongly with defense responses to repel any invading pathogen. The plant immune system can be triggered by exogenous or endogenous elicitor molecules. Another class of elicitors are defense promoting compounds which are also known as synthetic elicitors. Here I describe the discovery and characterization of a novel family of potentially secreted small endogenous peptides (PROSCOOP) which members harbor small peptides (SCOOPs). I show that the SCOOP family is involved in plant defense and root development. Various SCOOP peptides induce short- and long-term defense responses. Moreover, treatments with the SCOOP12 peptide induce the resistance against Pseudomonas syringae in Arabidopsis. In the second part of this thesis, I show that treatments with a synthetic elicitor can lead to long-term transcriptional memory and that subsequent challenging of such plants with an exogenous elicitor reverted this transcriptional memory. In conclusion, my thesis shows (1) how diverse the function of these elicitors can be and (2) the impact the plant defense system and its triggers have on plant development and memory

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Mmelesi, Olga Kelebogile. « Synthesis and characterization of pine cone carbon supported iron oxide catalyst for dye and phenol degradation ». Thesis, Vaal University of Technology, 2017. http://hdl.handle.net/10352/418.

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M. Tech. (Department of Chemical Engineering, Faculty of Engineering and Technology), Vaal University of Technology
Fenton oxidation is classified into two processes, homogeneous and heterogeneous. Homogeneous Fenton oxidation process, have been shown to be efficient in the degradation of organic pollutants. However, it was shown to have limitations which can be addressed by the heterogeneous Fenton oxidation. Despite the high efficiency of the heterogeneous Fenton oxidation process in the degradation of recalcitrant organic pollutants, the currents synthesis trends of the heterogeneous Fenton catalyst have been proven to be time and energy constraining, since it involves the multi-step were the activated carbon have to be prepared first then co-precipitate the iron oxide on the activated carbon. However, as much as the heterogeneous Fenton catalyst has been proven to have high catalytic activity towards degradation of organic pollutants, these catalysts have some limitations, such limitations include metal ions being leached from the catalyst support into the treated water causing catalyst deactivation and a secondary pollution to the treated water. In this thesis, these catalysts have been applied in the degradation of recalcitrant organic pollutants such as methylene blue and phenols. This study focuses on the single step synthesis of iron oxide nanoparticles supported on activated carbon, were carbonaceous material is impregnated with iron salt then pyrolysed via microwave heating. Microwave power and the amount of iron salt were optimized. The prepared activated carbon-iron oxide composites were applied to the degradation of 2-nitrophenol (2-NP) and methylene blue (MB). Methylene blue was used as a model compound due to the fact that it is easier to monitor the degradation process with UV-Vis as compared to 2-nitrophenol . 2-nitrophenol the additional step for the adjustment of pH is required since nitrophenols are colorless in color at lower pH. The characterization showed that the microwave power and the amount of the iron precursor have an influence on the porosity and surface functional groups of the activated carbon. Further it was vi observed that microwave power and iron precursor influnces the amount of iron oxide formed on the surface of the support. It was also observed that the activated carbon-iron oxide composite have the catalytic effects on the Fenton oxidation process of MB and 2-NP. The parameters such as H2O2, pH, catalyst dose, initial concentration, temperature affect the degradation of both MB and 2-NP. Kinetics studies showed that Fenton is a surface driven reaction since the results fitted the pseudo first order model. The thermodynamics parameters also showed that the reaction is endothermic, spontaneous and is randomized. This implies that the reaction of the degradation of MB and 2-NP is feasible and the catalysts prepared have high catalytic activity. MB and 2-NP were degraded to smaller organic molecules (carboxylic acids). The stability of the catalyst observed to decrease as the number of cycles increased, this is due to the leaching of iron ions from the support material. Hence it was concluded that the activated carbon-iron oxide composite was successfully synthesized and had the high catalytic activity for the degradation of MB and 2-NP.

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Shih, Sharon Min-Hsuan Biotechnology &amp Biomolecular Sciences Faculty of Science UNSW. « Transient viral infection of plant tissue culture and plants for production of virus and foreign protein ». Awarded by:University of New South Wales, 2007. http://handle.unsw.edu.au/1959.4/34967.

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This work was aimed to investigate the basic viral infection protocols mainly focusing on Nicotiana benthamiana hairy root cultures and wild-type tobacco mosaic virus (TMV). The application of transgenic virus containing the gene for green fluorescent protein (GFP) for foreign protein production in plant tissue cultures and whole plants was also studied. The effect on viral accumulation of the form of plant tissue culture used, such as hairy roots, shooty teratomas and suspended cells, was investigated. Viral infection was shown to have no effect on culture growth and morphology. Hairy root cultures are a superior host for viral propagation and production in vitro. The maximum specific rate of viral accumulation occurred mainly during the root growth phase. The average maximum virus concentration in the hairy roots was 0.82 ?? 0.14 mg g-1 dry weight and virus protein represented a maximum of approximately 6% of total soluble protein in the root biomass. Proportional scale-up of TMVinfected hairy roots in shake flasks and bioreactors can be achieved without changing the average virus concentration accumulated in the hairy roots. The level of viral accumulation was much lower in N. benthamiana hairy roots infected with transgenic virus containing GFP (TMVGFPC3) compared with TMV and low levels or no GFP was detected. Viral accumulation and GFP production in whole plants was studied using different generations of transgenic TMV-GFPC3 virus. Hybrid viruses with the foreign gene GFPC3 deleted may have been formed in successive TMV-GFPC3 generations, resulting in the loss of GFP production and enhanced viral infectivity. In vitro generated RNA transcript and first generation TMV-GFPC3 were found to be more suitable for infection than the second generation TMV-GFPC3. However, the accumulation of GFP and virus concentration did not occur at the same ratio. Provided a more genetically stable transgenic viral vector is used for infection, transient viral infection of hairy roots can be a potential alternative system for foreign protein production than plants grown in the field as the containment or safety issues can be addressed.

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Leung, Ching-man, et 梁靜雯. « Characterization of two auxin-induced ACC synthase genes in tomatoes ». Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B36748845.

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Macaulay, Keith Malcolm. « Salicylic acid biosynthesis in higher plants ». Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609202.

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Nell, Hanlie. « Genetic manipulation of sucrose-storing tissue to produce alternative products ». Thesis, Link to the online version, 2007. http://hdl.handle.net/10019/1136.

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Crooks, Colin Andrew. « Synthesis of operating procedures for chemical plants ». Thesis, Imperial College London, 1992. http://hdl.handle.net/10044/1/7795.

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Romagnano, Joseph F. « Ethylene Synthesis and Sensitivity in Crop Plants ». DigitalCommons@USU, 2008. https://digitalcommons.usu.edu/etd/16.

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The gaseous plant hormone ethylene is a small molecule that regulates developmental change. Research was conducted in three areas: sensitivity, synthesis, and alterations to synthesis. Vegetative pea plants were more sensitive than radish plants to atmospheric ethylene. Light intensity did not affect ethylene sensitivity. Ethylene synthesis rates were measured for unstressed cotton, corn, soybean, and tomato plants. The per-plant ethylene synthesis rate ranged from 0.1-80 pmol plant-1 s-1. However, when normalized to net photosynthetic rate, this range was 1-4 µmol of ethylene synthesis per mol of CO2 uptake. Diurnal cycles in ethylene synthesis were present in all crops studied. These cycles were disrupted by drought stress and were attenuated when synthesis rates underwent large changes. Drought stress decreased synthesis in cotton. Flooded corn and soybean had increased synthesis. Blocked perception had no effect on ethylene synthesis or net photosynthetic rate in healthy unstressed plants.

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Nate, Zondi. « Green synthesis of copper and silver nanoparticles and their antimicrobial activity ». Thesis, Vaal University of Technology, 2018. http://hdl.handle.net/10352/424.

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M. Tech. (Department of Chemistry, Faculty of Applied and Computer Sciences), Vaal University of Technology
The present study includes the use of a green synthetic method to prepare copper and silver nanoparticles using chitosan, aqueous extracts of Camellia sinensis, Combretum molle and Melia azedarach linn leaves. This study aims to investigate the influence of capping and precursor concentration on the properties of silver nanoparticles with emphasis on the medicinal plants chosen. The effect of capping agent on the properties of copper nanoparticles is also investigated. The phytochemical properties of plant extracts and the antimicrobial activity of the synthesized particles were also studied; this was achieved by using microdilution bioassay. Decoction method was used to extract secondary metabolites from plant leaves. Preliminary phytochemical screening carried out on the aqueous extracts of the plant leaves showed the presence of tannins, proteins, flavonoids, phenols, and carbohydrates. The total phenolic and flavonoids content of the aqueous extract was determined using spectroscopic methods. The highest phenolic content was found in the aqueous extract of Combretum molle (135 mg/g), and the highest flavonoid content was found in the aqueous extract of Camellia sinensis (0.4 mg/g). Characterization was done by a combination of spectroscopic, microscopy and XRD techniques. Both the size and shape of the synthesized silver nanoparticles were dependent on the identity of the capping molecule, precursor and capping agent concentration as depicted from their TEM and XRD results. Silver nanoparticles were found to be predominantly spherical. The capping agent concentration was also found to influence the degree of agglomeration, with an increase in capping agent concentration giving lesser agglomeration. FTIR spectral analysis showed that silver nanoparticles interact with bioactive compounds found in the plants through the hydroxyl functional group. Other shapes including diamond were observed for the effect of precursor concentration. The XRD micrographs revealed a face-centered cubic geometry and the phase remained the same with an increase in precursor concentration. The synthesized silver nanoparticles were all blue shifted compared to the bulk material. The TEM results revealed that copper nanoparticles with different sizes and shapes were successfully synthesized. All the prepared copper and silver nanoparticles showed satisfactory antifungal and antibacterial activity against Candida albicans, Cryptococcus neoformans, Staphylococcus aureus, Enterococcus faecalis, Klebsiella pneumonia and Pseudomonas aeruginosa. The capping molecules used in this study also showed some antibacterial and antifungal activity against the selected strains. However nanoparticles performed better than these capping molecules. Both silver and copper nanoparticles were found to be more active against gram-negative bacteria compared to gram-positive bacteria. Amongst all the prepared silver nanoparticles Combretum molle capped nanoparticles were found to be the most active nanoparticles. Also with copper nanoparticles, it was found that Combretum molle capped nanoparticles were the most active nanoparticles. Between the two metal nanoparticles, silver nanoparticles showed high antibacterial and antifungal activity compared to copper nanoparticles. The antioxidant activity of silver nanoparticles was assessed using 2.2-diphenyl-1-picrylhydrazyl. Silver nanoparticles were found to have some antioxidant activity. However, the capping molecules were found to be more active than the synthesized nanoparticles. This observation is attributed to the presence of some bioactive compounds in the plant extracts.

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Benning, Rainer. « Novel process synthesis in ultra high temperature plants ». [S.l. : s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=969425066.

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Russell, Leslie Wallace. « Control system synthesis for plants with time delays ». Thesis, Imperial College London, 2011. http://hdl.handle.net/10044/1/7650.

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Johnston, James E. « Synthesis of control structures for complete chemical plants ». Thesis, Massachusetts Institute of Technology, 1991. http://hdl.handle.net/1721.1/52937.

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Lakshmanan, Ramachandran. « Synthesis of operating procedures for complete chemical plants ». Thesis, Massachusetts Institute of Technology, 1990. http://hdl.handle.net/1721.1/14269.

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Eaton, Alexander Lee. « Isolation and Synthesis of Bioactive Compounds from Plants ». Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/64367.

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As a part of a continuing search for bioactive compounds with the International Cooperative Biodiversity Group (ICBG), and in collaboration with the Natural Products Discovery Institute of the Institute for Hepatitis and Virus Research (IHVR), twelve plant extracts were investigated for their antiproliferative activity against the A2780 cell line, three plant extracts were investigated for their antimalarial activity against Plasmodium falciparum, and three plant extracts were investigated for their anti-inflammatory activity (PPAR-y inhibition). Bioassay-guided fractionation of extracts led to the identification of four new antiproliferative compounds (2.1-2.3, 3.1), five new anti-inflammatory compounds (6.4a, 6.5a-b, 6.6a, 6.6c), and twenty-eight known compounds from eight of the extracts. In addition, mallotojaponin C, an antimalarial natural product, and derivatives were synthesized and investigated for their antimalarial activity.
Ph. D.

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Palaty, Jan. « Oxidative coupling of dibenzylbutanolides catalyzed by plant cell culture extracts ». Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/29710.

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This thesis aims to develop a new and inexpensive synthetic route to the anti-cancer drug etoposide (6) via 4'-demethylpodophyllotoxin (4) or 4'-demethylepipodophyllotoxin (5) involving the oxidative coupling of a dibenzylbutanolide catalyzed by a cell-free extract (CFE) from plant cell culture. This step was studied in depth using the Catharanthus roseus CFE-catalyzed biotransformation of frans-2-(3,5-dimethoxy-4-hydroxybenzyl)-3-(3-hydroxy-4-methoxybenzyl)butanolide (58) to 1-(3,5-dimethoxy-4-hydroxyphenyl)-6-hydroxy-3-hydroxymethyl-7-methoxy-1,2,3,4-tetrahydro-2-naphthoic acid γ lactone (59) as a model. The optimum values of reaction pH, enzyme:substrate ratio and co-factonsubstrate ratio were determined. The butanolide 58 was synthesized by a route involving the Stobbe condensation of 3-benzyloxy-4-methoxybenzaldehyde with dimethylsuccinate to yield 2-(3-benzyloxy-4-methoxybenzylidene)butanedioic acid 1-methyl ester (69). Hydrogenation of 69 to 2-(3-benzyloxy-4-methoxybenzyl)butanedioic acid 1-methyl ester (70) followed by reductive lactonization afforded 3-(3-benzytoxy-4-methoxybenzyl)butanolide (71). Alkylation of 71 with 4-benzyloxy-a-bromo-3,5-dimethoxytoluene (72) gave frans-2-(4-benzyloxy-3,5-dimethoxybenzyl)-3-(3-benzyloxy-4-methoxybenzyl)butanolide (73) which was then converted to the butanolide 58 by catalytic hydrogenolysis. In order to investigate the effect of different aromatic substituents on the oxidative coupling of butanolides, C. roseus CFE-catalyzed biotransformations of frans-2-(3,5-dimethoxy-4-hydroxybenzyl)-3-(3,4-methylenedioxybenzyl)butanolide (74) and frans-2-(3,5-dimethoxy-4-hydroxybenzyl)-3-(3,4-dihydroxy-a-hydroxybenzyl)butanolide (94) were also performed. The biotransformation of 74 gave 2-(3,5-dimethoxy-4-hydroxybenzylidene)-3-(3,4-methylenedioxybenzyl)butanoiide (76) as the sole isolated product. A pathway involving oxidative demethylatton is proposed to account for the balance of the unrecovered material. The butanolide 94, a potential precursor to etoposide, was prepared from piperonal. The lithium anion of 1-bis(phenylthio)methyl-3,4-methylenedioxybenzene (97) and the bromide 72 were added consecutively to but-2-en-4-olide to afford frans-2-(4-benzyloxy-3,5-dimethoxybenzyl)-3-(3,4-methylenedioxy-α,α-bis(phenylthio)benzyl)butanolide (96). A synthetic sequence involving the oxidation of 96 to frans-2-(4-benzyloxy-3,5-dimethoxybenzyl)-3-(3,4-methylenedioxybenzoyl)-butanolide (100), reduction to frans-2-(4-benzyloxy-3,5-dimethoxybenzyl)-3-(α-hydroxy-3,4-methylenedioxybenzyl)butanolide (109) and cleavage of the methylenedioxy and benzyl protecting groups gave the catechol 94. Unfortunately, the CFE-catalyzed oxidation of 94, following treatment with sodium borohydride, yielded 4-(3,4-dihydroxyphenyl)-5,7-dimethoxy-6-hydroxy-2-hydroxymethyl-1,2,3,4-tetrahydro-2-naphthoic acid γ lactone (103) as the sole isolated product. [Formulas omitted]
Science, Faculty of
Chemistry, Department of
Graduate

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39

Storey, Benjamin 1973. « AQX : a novel gene in plant ubiquinone biosynthesis ». Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=80882.

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C. elegans worms with mutations in the gene CLK-1 develop slowly and have an extended lifespan. CLK-1 encodes a mitochondrial protein that is responsible for the hydroxylation of 5-demethoxyubiquinone (DMQ), the penultimate step of ubiquinone (Coenzyme-Q or UQ) biosynthesis. Structural homologues of CLK-1 are found in mammals, fruit flies, yeast and some types of bacteria. Interestingly, however, there is no structural homologue of CLK-1 in the Arabidopsis genome and no plant homologue can be found in other sequence databases. Yeast with the CLK-1 homologue COQ7 deleted fail to grow on non-fermentable carbon sources. To identify a plant functional homologue of COQ7/CLK-1, an Arabidopsis cDNA expression library was screened for complementation of a yeast coq7 deletion mutant. A clone was identified that rescued the coq7 respiratory deficiency. Although the sequence of the encoded protein has no structural similarity to proteins in the COQ7/CLK-1 family, it contains a monooxygenase/hydroxylase domain that has sequence similarity with the E. coli DMQ hydroxylase encoded by the UBIF gene. Like the structural homologues of COQ7/CLK-1 found in other eukaryotes, the gene (AQX for 'Alternate Quinone monooXygenase') contains a likely mitochondrial targeting presequence at its N-terminus. HPLC analysis of quinone extracts from rescued cog7 strains does not detect ubiquinone, but instead shows another peak that may be DMQ. It is likely that AQX does not hydroxylate yeast DMQ effectively enough to generate detectable levels of UQ. A unique pathway for UQ biosynthesis in plants is proposed that is defined by AQX and Arabidopsis genes identified on the basis of homology to known E. coli and yeast UQ biosynthesis genes.

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Lee, Hyun-Jung. « Optimization of Fischer-Tropsch plant ». Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/optimization-of-fischertropsch-plant(236736b1-dae6-41ea-a234-576d226beff1).html.

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Fischer-Tropsch synthesis is the technology for converting fuel feedstocks such as natural gas and coal into transportation fuels and heavy hydrocarbons. There is scope for research and development into integrated processes utilising synthesis gas for the production of a wide range of hydrocarbons. For this purpose there should be strategies for the development of Fischer-Tropsch processes, which consider both economic and technological feasibilities. The aim of this study was to optimize Fischer Tropsch Plants in order to produce gasoline and gas oil by investigating the benefits of recycling & co-feeding of unconverted gas, undesired compounds, and lighter hydrocarbons over iron-based catalysts in order to save on capital and operating costs. This involved development of FT models for both two-phase and three-phase reactors. The kinetic parameters for these models were estimated using optimization with MATLAB fitting to experimental data and these models were then applied to ASPEN HYSYS flowsheets in order to simulate nine different Fischer-Tropsch plant designs. The methodology employed involved qualitative modelling using Driving Force Analysis (DFA) which indicates the necessity of each compound for the Fischer-Tropsch reactions and mechanism. This also predicts each compounds influence on the selectivity of different products for both two-phase and three-phase reactors and for both pure feeding and co-feeding arrangements. In addition, the kinetic models for both two-phase and three-phase reactor were modified to account for parameters such as the size of catalyst particles, reactor diameter and the type of active sites used on the catalyst in order to understand and quantify their effects. The kinetic models developed can describe the hydrocarbon distributions consistently and accurately over large ranges of reaction conditions (480-710K, 0.5-2.5MPa, and H2/CO ratio: 0.5-2.5) over an iron-based catalyst for once-through processes. The effect of recycling and co-feeding on the iron-based catalyst was also investigated in the two reactor types. It was found that co-feeding unwanted compounds to synthesis gas increases the production of hydrocarbons. This recycling and co-feeding led to an increase in H2/CO feed ratio and increased selectivity towards C5+ products in addition to a slightly increased production of light hydrocarbons (C1-C4). Finally, the qualitative model is compared with the quantitative models for both two-phase and three-phase reactors and using both pure feeding and co-feeding with the same reactor conditions. According to the detailed quantitative models developed, in order to maximize hydrocarbon production pressures of 2MPa, temperatures of 450K and a H2/CO feed ratio of 2:1 are required. The ten different Fischer-Tropsch plant cases were based on Fischer-Tropsch process. FT reactor models were built in ASPEN HYSYS and validated with real FT plant data. The results of the simulation and optimization supported the proposed process plant changes suggested by qualitative analysis of the different components influence. The plants involving recycling and co-feeding were found to produce higher quantities of gasoline and gas oil. The proposed heuristic regarding the economic scale of the optimized model was also evaluated and the capital cost of the optimized FT plant reduced comparison with the real FT plant proposed by Gerard. Therefore, the recycling and co-feeding to FT reactor plant was the best efficiency to produce both gasoline and gas oil.

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Al-Easa, Hala Sultan Saif. « An investigation of the plant Centaurea Sinaica ». Thesis, University of Reading, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.279585.

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Palmos, John D. N. « Controller synthesis for performance stabilization of unstable, uncertain plants ». Honors in the Major Thesis, University of Central Florida, 1997. http://digital.library.ucf.edu/cdm/ref/collection/ETH/id/178.

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This item is only available in print in the UCF Libraries. If this is your Honors Thesis, you can help us make it available online for use by researchers around the world by following the instructions on the distribution consent form at http://library.ucf.edu/Systems/DigitalInitiatives/DigitalCollections/InternetDistributionConsentAgreementForm.pdf You may also contact the project coordinator, Kerri Bottorff, at kerri.bottorff@ucf.edu for more information.
Bachelors
Engineering
Electrical Engineering

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麥文馨 et Man-hing Mak. « The characterization of tomato plants transformed with various anti-sense ACC synthase genes ». Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2001. http://hub.hku.hk/bib/B31226504.

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Hawker, John Seth. « Sucrose and starch metabolism in leaves, storage organs and developing fruits of higher plants ». Title page, contents and summary only, 1988. http://web4.library.adelaide.edu.au/theses/09SD/09sdh392.pdf.

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Kola, Ramya Sree. « Generation of synthetic plant images using deep learning architecture ». Thesis, Blekinge Tekniska Högskola, Institutionen för datavetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-18450.

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Background: Generative Adversarial Networks (Goodfellow et al., 2014) (GANs)are the current state of the art machine learning data generating systems. Designed with two neural networks in the initial architecture proposal, generator and discriminator. These neural networks compete in a zero-sum game technique, to generate data having realistic properties inseparable to that of original datasets. GANs have interesting applications in various domains like Image synthesis, 3D object generation in gaming industry, fake music generation(Dong et al.), text to image synthesis and many more. Despite having a widespread application domains, GANs are popular for image data synthesis. Various architectures have been developed for image synthesis evolving from fuzzy images of digits to photorealistic images. Objectives: In this research work, we study various literature on different GAN architectures. To understand significant works done essentially to improve the GAN architectures. The primary objective of this research work is synthesis of plant images using Style GAN (Karras, Laine and Aila, 2018) variant of GAN using style transfer. The research also focuses on identifying various machine learning performance evaluation metrics that can be used to measure Style GAN model for the generated image datasets. Methods: A mixed method approach is used in this research. We review various literature work on GANs and elaborate in detail how each GAN networks are designed and how they evolved over the base architecture. We then study the style GAN (Karras, Laine and Aila, 2018a) design details. We then study related literature works on GAN model performance evaluation and measure the quality of generated image datasets. We conduct an experiment to implement the Style based GAN on leaf dataset(Kumar et al., 2012) to generate leaf images that are similar to the ground truth. We describe in detail various steps in the experiment like data collection, preprocessing, training and configuration. Also, we evaluate the performance of Style GAN training model on the leaf dataset. Results: We present the results of literature review and the conducted experiment to address the research questions. We review and elaborate various GAN architecture and their key contributions. We also review numerous qualitative and quantitative evaluation metrics to measure the performance of a GAN architecture. We then present the generated synthetic data samples from the Style based GAN learning model at various training GPU hours and the latest synthetic data sample after training for around ~8 GPU days on leafsnap dataset (Kumar et al., 2012). The results we present have a decent quality to expand the dataset for most of the tested samples. We then visualize the model performance by tensorboard graphs and an overall computational graph for the learning model. We calculate the Fréchet Inception Distance score for our leaf Style GAN and is observed to be 26.4268 (the lower the better). Conclusion: We conclude the research work with an overall review of sections in the paper. The generated fake samples are much similar to the input ground truth and appear to be convincingly realistic for a human visual judgement. However, the calculated FID score to measure the performance of the leaf StyleGAN accumulates a large value compared to that of Style GANs original celebrity HD faces image data set. We attempted to analyze the reasons for this large score.

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Hao, Jingfang. « Investigating Key Metabolic Steps of NAD Synthesis in Arabidopsis thaliana ». Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS460.

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Le développement et le fonctionnement harmonieux des plantes dépendent de cofacteurs comme le nicotinamide adénine dinucléotide (NAD). Outre ses rôles dans le recyclage redox, le NAD est également impliqué dans les processus de signalisation cellulaire, qui sont des acteurs centraux dans les conditions de stress. Ainsi, le NAD est l'un des principaux déterminants de l'homéostasie de l'énergie des plantes et a un impact important sur la productivité des plantes et la résistance au stress. La L-aspartate oxydase (LASPO) et l'acide nicotinique / nicotinamide mononucléotide adénylyltransférase (N(a)NMNAT) sont deux enzymes importantes dans la biosynthèse du NAD. Par surproduction de ces deux enzymes dans E. coli, nous avons identifié les propriétés biochimiques de ces enzymes. Il ressort que la surexpression de la N(a)MNAT stimule la croissance des plantes en activant les métabolismes photosynthétiques et respiratoires, sans pour autant augmenter les teneurs en NAD. La surproduction de la LASPO augmente la teneur en NAD des plantes, laquelle est corrélée à une augmentation significative de la production de biomasse foliaire et des rendements en graines, et l’inverse est observé lorsque les teneurs en NAD diminuent. La modification des teneurs en NAD affecte les fonctions photosynthétiques et respiratoires, et l’expression de quelques gènes qui pourraient participer au contrôle de la croissance des plantes semble régulée par les histones déacétylases NAD-dépendantes
The development and smooth functioning of plants depends on co-factors such as nicotinamide adenine dinucleotide (NAD). In addition to its roles in redox recycling, NAD is also involved in cell signaling processes, which are central actors in stress conditions. Thus, NAD is one of the main determinants of plant energy homeostasis and has a significant impact on plant productivity and stress resistance. L-aspartate oxidase (LASPO) and nicotinic acid / nicotinamide mononucleotide adenylyltransferase (N (a) NMNAT) are two important enzymes in the biosynthesis of NAD. By overproducing these enzymes in E. coli, we have identified the biochemical properties of these enzymes. Overexpression of N(a)MNAT stimulates plant growth by activating photosynthetic and respiratory metabolisms, without increasing NAD levels. Overproduction of LASPO enhances NAD content in plants, which is correlated with a significant increase in foliar biomass production and seed yields, and the reverse is observed when NAD levels decrease. Changes in NAD levels affect photosynthetic and respiratory functions, and the expression of a few genes that may be involved in plant growth control appears to be regulated by NAD-dependent histones deacetylases

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Rowntree, Ellen Grace. « The control of 6-phosphofructo-2-kinase/fructose 2,6-bisphosphatase in plants ». Thesis, University of Oxford, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.337604.

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Gonzalez, José Artur Quilici. « Algoritmos de otimização de planos de teste de unidades funcionais para circuitos BIST ». Universidade de São Paulo, 2001. http://www.teses.usp.br/teses/disponiveis/3/3140/tde-18032002-143753/.

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Grandes saltos tecnológicos viabilizaram a integração de circuitos digitais de alta complexidade, com centenas de pinos e milhões de transistores. Sistematicamente, dispositivos eletromecânicos estão sendo substituídos por Circuitos Integrados (CIs) que contêm sistemas inteiros, ampliando o uso generalizada da eletrônica. Com o aumento da complexidade e quantidade de CIs produzidos, a tarefa de detectar de forma rápida e eficiente aqueles chips com problemas assumiu grande importância. Como a Testabilidade [McClu 86] de um CI afeta sua qualidade, um circuito que não é completamente testável, para um determinado modelo de falha, tem menos valor que outro inteiramente testável [De Mi 94]. Em estudos sobre confiabilidade, desempenho, custos e Testabilidade de circuitos VLSI verificou-se que o custo associado ao processo de testes de circuitos VLSI estava praticamente estabilizado, enquanto outros componentes do preço final do chip caíam. Por estas razões, a Testabilidade foi incorporada ao projeto desde suas concepções iniciais, apresentando geralmente resultados com menor Sobreárea e mínimo impacto no desempenho, quando comparado a CIs produzidos sem considerações relacionadas a testes. Uma técnica de teste que dispensa o uso de Equipamento Automático de Teste, conhecida como Autoteste Incorporado (em inglês, Built-In Self-Test BIST), consiste em adaptar partes do próprio CI para gerar Vetores de Teste, comprimir e analisar os resultados. A técnica BIST tem sido empregada com sucesso em ambientes de projeto de Síntese de Alto Nível (High Level Synthesis, HLS), que tende a reduzir o tempo de projeto de um ASIC, auxiliando a determinação da arquitetura RTL [Stru et al. 99]. Nesta dissertação, considera-se uma forma específica de BIST, o structural off-line BIST [Abr et al. 90], em que o Autoteste se dá quando o CI digital é retirado de sua operação normal e colocado em modo teste, para que um Plano de Teste para Unidades Funcionais seja executado (na fase de manufatura e/ou de serviço em campo). O Plano de Teste, baseado em uma descrição estrutural do CI, é gerado por um algoritmo concebido para detectar os registradores que devem ser reconfigurados em Geradores de Padrões de Teste (em inglês, Test Pattern Generators, TPGs) e Analisadores de Assinatura (Signature Analyzers, SAs). O critério de seleção dos registradores baseia-se numa Função Custo, que avalia globalmente o grau de compartilhamento de cada registrador candidato, e a contribuição que a sua eventual escolha causaria no tempo final de teste. Os Registradores de Teste, reconfigurados em Autômatos Celulares (Cellular Automata, CAs), devem operar segundo um Rule Number, neste caso, Regra 90 ou 150. A tarefa do Autoteste paralelo é dividida em duas etapas: na primeira, a cada uma das Unidades Funcionais é associado o melhor momento possível para início de sua sessão de teste, resultando na construção gradativa de uma Matriz de Estado de Teste, e na segunda, com a Matriz de Estado de Teste já totalmente definida, é feita uma análise global para minimizar o número de candidatos a registrador de teste. O resultado final é um Plano de Teste Otimizado definindo as regras dos TPGs (TPG90 e/ou TPG150), o custo em termos de Sobreárea, o início da geração dos Vetores de Teste, sua duração e a Cobertura de Falha mínima.
Great technological developments have made possible the integration of digital circuits of high complexity, with hundreds of pins and million of transistors. Electromechanical devices are being systematically substituted for Integrated Circuits (ICs) that contain complete systems, extending the generalized use of electronics. With the increasing complexity and amount of ICs, the task of detecting faulty chips in a fast and efficient way has assumed great importance. As testability [McClu 86] affects the quality of an IC, a circuit that is not fully testable for one determined fault model has less value than another which is entirely testable [De Mi 94]. It was verified in studies on reliability, performance, costs and testability of VLSI circuits that the cost associated with tests was practically stabilized, while other components of the final price fell. For these reasons, testability was incorporated in the design since its initial conception, producing generally minor area overhead and minimum impact on the performance, when compared to ICs produced without test considerations. One test technique that eliminates de needs for use of Automatic Test Equipment, known as BIST - Built-In Self-Test, consists of adapting parts of the IC to generate Test Vectors, compress and analyze the results. The BIST technique has been used successfully in design of HLS - High Level Synthesis - environments, which tends to reduce the ASICs design time, easing the task of determining the RTL architecture [Stru et al. 99]. In this dissertation a specific form of BIST, the structural off-line BIST [Abr et al. 90], is considered. To start the self-test it is necessary to halt the normal operation of the digital IC and put it in test mode, so that a Test Plan for Functional Units is executed (in the phase of manufacture and/or in the field). The Test Plan based on the structure of the IC is generated by an algorithm conceived to detect the registers which will be reconfigured in TPGs - Test Pattern Generators, and SAs - Signature Analyzers. The criterion for selection of the registers is based on a Cost Function, which globally evaluates the degree of sharing of each register candidate, and the contribution that its eventual choice would cause in the final test time. The Test Registers reconfigured in CAs Cellular Automata - must operate according to a Rule Number, in this case Rule 90 or 150. The task of the parallel self-test is divided into two stages: in the first one, to each Functional Unit is associated the best possible moment for its test session beginning, resulting in the gradual construction of a Test Status Matrix, and in the second, with the Test Status Matrix completely defined, a global analysis is made to minimize the number of register candidates. The final result is an Optimized Test Plan, which defines the rules of the TPGs (TPG90 and/or TPG150), the area overhead cost, the beginning of the Test Vector Generation, its duration and the minimum Fault Coverage.

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Abdul-Rahman, M. M. « Studies on the biosynthesis of ligands and their production in plant cell cultures ». Thesis, University of Nottingham, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381094.

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Moore, John Wallace. « Foundation technologies in synthetic biology : tools for use in understanding plant immunity ». Thesis, University of Edinburgh, 2012. http://hdl.handle.net/1842/6225.

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The plant hormone salicylic acid (SA) is an essential activator of plant immune responses directed against biotrophic pathogens. The transcription cofactor NPR1 (Nonexpressor of pathogenesis- related (PR) genes 1) functions to transduce the SA signal into an operational response directed to limited pathogen damage. In the absence of pathogen, NPR1 protein resides in the cytoplasm as a large molecular weight oligomer held together by disulphide bonding. Initiation of defence signalling leads to changes in intracellular redox conditions that promote NPR1 momomer release. Translocation of monomeric NPR1 to the nucleus results in the activation of over 2200 immune-related genes in Arabidopsis. NPR1 lacks a canonical DNA-binding domain but is known to perform part of its regulatory function through engagement of TGA factors (bZIP transcription factor). Induction of SA-dependent signalling is invariably associated with PR-1 gene expression and accumulation of mRNA for this gene serves as a useful marker of defence activation. However, both functional redundancy and stochastic factors limit the effectiveness of standard genetic approaches used in plant research, and thus much of the hierarchal processes surrounding NPR1-dependent gene activation are not fully understood. Using a synthetic biology approach we aim to complete exploratory work and set the foundations for the development of a yeast tool that can be used to manipulate and subsequently understand NPR1 function in relation to interacting partners and gene activation. Accordingly, using this tool we sought to create a conceptual protein circuit based on theoretical plant immunity. In completing this work we have developed a Saccharomyces cerevisiae strain that exhibits a highly oxidising intracellular redox environment. This was achieved by knocking out genes encoding S-nitrosoglutathione reductase (SFA1), flavohemoglobin (YHB1) and YAP1 (bZIP transcription factor), all important components in regulating cellular redox homeostasis and protein S-nitrosylation state in S. cerevisiae. Characterisation of this cell (designated Δsfa1yap1yhb1) reveals a high tolerance to such redox perturbations. Importantly, NPR1 is by default, assembled predominantly in the oligomeric form in this biological chassis. By activating two inducible inputs in the form of Arabidopsis S-nitrosoglutathione reductase (AtGSNOR) and Thioredoxin (AtTRXh5) which both function to promote NPR1 monomerisation, we have created a switch to selectively control NPR1 oligomer-monomer equilibrium. To complete the synthetic circuit, TGA3 was included, along with a modified yeast MEL1 promoter that has been customised to contain the TGA-responsive upstream activation sequence (termed the as-1 element) present in the promoter region of the PR-1 gene. Using FRET tools we were able to confirm nuclear interaction between monomeric NPR1 and TGA3, with this association appearing to induce as-1 element binding. However this process is not sufficient to activate a Luciferase (LUC) reporter gene, even when the GAL4 activation domain (GAL4 AD) is fused to NPR1. Ordinarily, a CUL3-dependent proteolysis-coupled transcription cycle is necessary to maintain efficient NPR1-dependent gene transcription in Arabidopsis. Although S. cerevisiae encodes an evolutionarily related CUL3 ortholog, examination by western blot demonstrates that NPR1 protein is stable in this cell, indicating an endogenous mechanism to degrade NPR1 is either not present or not functional in yeast. As such, this synthetic yeast tool represents a completely novel approach to identify missing components functioning in NPR1-mediated transcriptional regulation. Furthermore, in collaboration with a skilled bioinformatician, and using a rule-based stochastic modeling tool known as Kappa, we have been able to develop, for the first time, a preliminary mathematical simulation representative of NPR1-dependent gene activation that can be used as a foundation for future works.

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