Global ETD Search

31	Control Method for Invasive Aquatic Species introduced via Ballast Water: Effects of Carbon Dioxide Supersaturation on Survivorship of Digesia tigrina (Planaria: Maculata) and Lirceus brachyurus (Isopoda: Crustacea) and Effect of High Hydrostatic Pressure Processing on Freely Suspended and Shellfish Associated T7 Bacteriophage Sheldon, Todd August 03 March 2005 (has links) Control Method for Invasive Aquatic Species introduced via Ballast Water: Effects of Carbon Dioxide Supersaturation on Survivorship of Digesia tigrina (Planaria: Maculata) and Lirceus brachyurus (Isopoda: Crustacea) Survivorship of an aquatic species of planaria (Digesia tigrina) and isopods (Lirceus barchyurus) to elevated levels of carbon dioxide (CO₂) was determined. Both planaria and isopods were exposed to levels of freshwater supersaturated with carbon dioxide, and percent mortality was calculated for various exposure durations, and at various pressure levels. The data collected were graphically analyzed to determine the time necessary to produce mortality in 50% (LT50) of any given sample of specimens tested at a certain pressure level. At 38.6 kPa, 103.4 kPa and 172.4 kPa, the LT50 for planaria was calculated to be 150.3 ± 10.1, 58.6 ± 11.1, and 27.8 ± 6.2 minutes, respectively. At 38.6 kPa, 103.4 kPa and 172.4 kPa , the LT50 for isopods was calculated to be 181.1 ± 52.5, 79.7 ± 21.9, and 40.5 ± 17.0 minutes, respectively. These results suggest that CO₂ supersaturation may be an easily applied, efficient method that would end the unwanted introduction of nonnative aquatic species to habitats via ballast water released from shipping vessels. Effect of High Hydrostatic Pressure Processing on Freely Suspended and Shellfish Associated T7 Bacteriophage The effectiveness of hydrostatic pressure processing (HPP) for inactivating viruses has only been evaluated in a limited number of studies and most of the work has been performed with freely suspended viruses. In this work, the inactivation of freely suspended, as well as shellfish associated bacteriophage T7, by HPP was studied. T7 was selected in hopes that it could potentially serve as a model for animal virus behavior. Both clams (Mercenaria mercenaria) and oysters (Crassostrea virginica) were homogeneously blended separately and inoculated with bacteriophage T7. The inoculated shellfish meat, as well as freely suspended virus samples, were subjected to HPP under the following conditions: 2, 4 and 6 min durations; 241.3, 275.8 and 344.7 Megapascals (MPa) pressure levels; and temperature ranges of 29.4 – 35, 37.8 – 43.3 and 46.1 – 51.7Ë C. Plaque forming unit (PFU) reductions of 7.8 log10 (100% inactivation) were achieved for freely suspended T7 at 344.7 MPa, 2 min and 37.8 – 43.3Ë C. At 46.1 – 51.7Ë C, T7 associated with either clams or oysters was inactivated at nearly 100% (> 4 log10) at all pressure levels and durations tested. The results indicated that T7 is readily inactivated by HPP under the proper conditions, may be protected or made more susceptible by shellfish meat, and may serve as a viable model for the response of several animal viruses to HPP. / Master of Science carbon dioxide T7 bacteriophage invasive species planaria and high pressure processing ballast shellfish
32	Adaptations de la méthode de purification d’ARN par affinité avec l’étiquette ARiBo Salvail-Lacoste, Alix 08 1900 (has links) Dans les dernières années, une explosion de la recherche sur les ARN a eu lieue à cause de nombreuses découvertes démontrant l’importance de l’ARN dans plusieurs processus biologiques. Ainsi, de grandes quantités d’ARN sont devenues indispensables au bon déroulement de plusieurs études, notamment pour la biologie structurale et la caractérisation fonctionnelle. Cependant, il existe encore peu de méthodes de purification simples, efficaces, fiables et produisant un ARN sous forme native. Dans les dernières années, le laboratoire Legault a mis au point une méthode de purification par affinité utilisant une étiquette ARiBo pour la purification d’ARN transcrits in vitro par la polymérase à ARN du phage T7. Cette méthode de purification d’ARN a été spécifiquement développée pour maximiser la pureté et le rendement. De plus, elle est très rapide et fonctionne avec plusieurs types d’ARN. Cependant, comme plusieurs autres méthodes de purification, cette méthode produit des ARN avec des extrémités 5′ hétérogènes. Dans ce mémoire, des solutions sont proposées pour remédier au problème d’hétérogénéité en 5ʹ′ des ARN transcrits avec la polymérase à ARN du phage T7 et purifiés par la méthode ARiBo. La première solution consiste à choisir la séquence en 5′ parmi celles des 32 séquences testées qui ne présentent pas d’hétérogénéité en 5ʹ′. La seconde solution est d’utiliser une étiquette clivable en 5ʹ′ de l’ARN d’intérêt, tel que le ribozyme hammerhead, déjà utilisée pour ce genre d’application, ou le système CRISPR/Cse3 que nous proposons dans l’article présenté dans ce mémoire. De plus, nous avons adapté la méthode ARiBo pour rendre possible la purification d’un long ARN de 614 nt, le polycistron miR-106b-25. Nous avons également démontré la possibilité d’utiliser la méthode ARiBo pour l’isolation de protéines qui se lient à un ARN donné, le précurseur de miRNA pre-miR-153-2. En conclusion, ce mémoire démontre la possibilité d’adapter la méthode ARiBo à plusieurs applications. / In recent years, the field of RNA research has exploded due to several discoveries demonstrating the importance of RNA in many biological processes. Along with the increased interest in this field, large amounts of RNA have become essential to the success of several studies, in particular for structural biology and functional characterization. However, there are still very few native purification methods that are simple, efficient and reliable. In the past few years, the Legault laboratory has established an affinity purification method using an ARiBo tag to purify RNAs produced by in vitro transcription with the T7 RNA polymerase. This RNA purification method was specifically developed to maximise purity and yield. In addition, this method is fast and works with several types of RNAs. However, like several other purification methods, this method produces RNAs with 5' heterogeneity. This Master’s thesis propose solutions to overcome the problem of 5' heterogeneity for RNAs transcribed with the T7 RNA polymerase and purified with the ARiBo method. The first solution proposed is to choose a 5' sequence among those of the 32 sequences tested that do not present 5'- heterogeneity. The other possibility is the use of a cleavable tag at the 5'-end of the RNA of interest, such as the hammerhead ribozyme, already used for this purpose or the CRISPR/Cse3 system, which is presented here. Furthermore, we have adapted the ARiBo method to purify an RNA of 614 nt, the miRNAs cluster miR- 106b-25. We also demonstrate the possibility to use the ARiBo method to isolate proteins that bind a given RNA, the miRNA precursor pre-miR-153-2. In conclusion, this Master’s thesis demonstrates the possibility of adapting the ARiBo method for several applications. Purification d'ARN par affinité Polymérase à ARN du phage T7 Hétérogénéité en 5' CRISPR/Cse3 Ribozyme Hammerhead Complexe ribonucléoprotéique RNA affinity purification ARiBo tag T7 RNA polymerase 5' heterogeneity CRISPR/Cse3 Hammerhead ribozyme Ribonucleoprotein complex
33	On subsistence and human rights Tomalty, Jesse January 2012 (has links) The central question I address is whether the inclusion of a right to subsistence among human rights can be justified. The human right to subsistence is conventionally interpreted as a fundamental right to a basic living standard characterized as having access to the material means for subsistence. It is widely thought to entail duties of protection against deprivation and duties of assistance in acquiring access to the material means for subsistence (Shue 1996, Nickel, 2004, Griffin 2008). The inclusion of a right to subsistence among human rights interpreted in this way has been met with considerable resistance, particularly on the part of those who argue that fundamental rights cannot entail positive duties (Cranston 1983, Narveson 2004, O’Neill 1996, 2000, 2005). My purpose in this dissertation is to consider whether a plausible interpretation of the human right to subsistence can succeed in overcoming the most forceful and persistent objections to it. My main thesis is that a minimal interpretation of the human right to subsistence according to which it is a right not to be deprived of access to the means for subsistence provides the strongest interpretation of this right. Although the idea that the human right to subsistence correlates with negative duties is not new, discussion of these duties has been overshadowed in the literature by debate over the positive duties conventionally thought to be entailed by it. I show that the human right to subsistence interpreted as a right not to be deprived of access to the means for subsistence makes an important contribution to reasoning about the normative implications of global poverty. 340
34	Marriage and desire in seventeenth-century French comedy Townshend, Sarah Elizabeth January 2015 (has links) This thesis re-examines the role of marriage in the golden age of seventeenth-century French comedy. It reconsiders received wisdom on the subject to challenge acceptance of the final promise of marriage as a dénouement complet to comedy. Through an analysis of the themes of discontent, cuckoldry, fertility, non-heteronormative desire and widowhood, it offers an alternative view of what comedy can encompass. Close reading of works by Molière, Quinault, (Thomas) Corneille, (Françoise) Pascal, Ulrich and de Visé establishes that comedy can be both enjoyable and satisfying while incorporating elements that conflict with the marriage ideal. This thesis does not attempt to provide a full socio-historical reading of seventeenth-century attitudes to marriage, although an understanding of contemporary attitudes provides a starting point for close textual analysis. Critical theories, notably gender theory, are used where appropriate to further clarify the role of marriage in comedy. Chapter One presents and problematizes the framework of marriage as the structuring principle of comedy, drawing on themes of compatibility, discontent and desire. The second chapter focuses on anxiety regarding cuckoldry in comedy, relating it to the promise of marriage. An analysis of the desires of older characters in projected comedic marriages, particularly as these desires relate to fertility, is the guiding principle of Chapter Three, which also sets out essential terms of reference for the fourth chapter on widowhood and queer desire. The thesis demonstrates that rather than constituting a satisfying and happy ending, a constant challenge is posed to the promise of marriage by on-stage marriages, fears of cuckoldry, widowhood, and ‘inappropriate' or queer desires. I propose a more nuanced reading, showing that comedy can be fully satisfying and structurally complete without a final promise of marriage, and that, rather, comedy can incorporate significant elements that appear antithetical to the ideal of marriage typically associated with the genre. 842
35	Evolution of microbial populations with spatial and environmental structure Miller, Eric Louis 07 January 2011 (has links) Rarely are natural conditions constant, but generally biologists study microbes in artificially constant environments in the laboratory. I relaxed these assumptions of constant environments through time and space as I investigated how microbial populations evolve. First, I examined how bacteriophage evolved in the presence of permissive and nonpermissive hosts. I found that bacteriophage evolved discrimina- tion in mixed environments as well as in one of two environments with homogeneous, permissive hosts. This showed the asymmetry of host-shifting in viruses as well as the possibility of large, and somewhat unpredictable, pleiotropic effects. Secondly, I reconstructed ancestral environmental conditions for soil bacteria groups using phy- logenetics and environmental variables of extant species’ habitats. These generaliza- tions suggested characteristic phenotypes for several phylogenetic groups, including uncultured Acidobacteria. Lastly, I collected genetic sequences and global collection information for 65 bacteria genera across the domain. In examining the relation- ship between genetic distance, environmental conditions, and geography, I observed positive relationships specifically between genetic distance and geography or genetic distance and environmental conditions for bacteria from land sites but not from wa- ter sites. Phylogenic classifications or phenotypes of the genera could not predict these correlations. In all of these projects, variations in the environment created evolutionary signals that hinted at past environments of microbial populations. / text Ecology Evolution Microbiology Experimental evolution Adsorption Antagonistic pleotropy T7 Soil bacteria Bacteria Microbial ecology Phylogenetics Dispersal Biogeography 16S
36	Transcription par une ARN Polymerase : mesures de forces à l'échelle de la molécule unique Thomen, Philippe 06 December 2002 (has links) (PDF) Nous avons réalisé une expérience à l'échelle de la molécule unique pour étudier l'influence d'une force mécanique sur la transcription par l'ARN polymérase du phage T7. Cette enzyme, prototype de moteur moléculaire, est très processive et partage des homologies avec les membres de la famille Pol I incluant la transcriptase inverse du VIH 1. Une extrémité de l'ADN à transcrire est tenue par une polymérase fixée sur une surface, l'autre extrémité est attachée à une bille microscopique capturée à l'aide d'un piège optique interférométrique qui permet de mesurer la force développée durant la transcription. Des mesures de vitesse de transcription ont été réalisées dans la gamme 5-20 pN, à différentes concentrations en nucléotides (NTP). On observe que la diminution de la concentration en NTP, qui rend l'étape de liaison du nucléotide dans le site actif limitante, fait apparaître une dépendance marquée de la vitesse à la force, alors que les hautes concentrations en NTP rendent la polymérase insensible à la force. On en déduit que le mouvement d'avancée de l'enzyme le long de l'ADN est couplé à la fixation du nucléotide dans le site actif. Ainsi l'énergie d'hydrolyse n'est pas directement convertie en énergie mécanique. Les homologies entre polymérases suggèrent que ce mécanisme est également partagé, ce qui permet de proposer que pour les polymérases en général, l'étape de fixation du nucléotide dans le site actif est couplé au mouvement sur l'ADN.<br /><br />Nous avons également mené un autre type d'expérience en mesurant la force lors de l'ouverture mécanique de la double hélice d'ADN, qui a permis de déterminer la friction exercée sur l'ADN en rotation.<br /><br />La configuration d'ouverture de l'ADN a été également utilisée pour étudier l'interaction d'une protéine, EcoR V avec l'ADN. L'analyse des résultats a mis en évidence une grande variabilité dans l'énergie de dissociation, liée à des différences d'affinités entre les sites de reconnaissance spécifiques de l'enzyme. ADN transcription ARN polymérase de T7 molécule unique moteur moléculaire ouverture piège optique friction rotation EcoR V
37	Rolling circle transcription on smallest size double stranded DNA minicircles Kristoffersson, Anders January 2010 (has links) The RNA polymerase T7 is utilized as a component of motor complexes in DNA nanotechnology due to its high promotor specificity, the lack of external transcription factors and its very high processivity, but there is no experience of its application on small double stranded DNA circles. Circular templates from 210 to 126 bp in circumference sharing a common promotor termination motif were synthesized and transcription was monitored at end point on gel and in real time with a 2’ O methyl RNA molecular beacon. The RNAP T7 was found to be able to utilize circular dsDNA templates down to 126 bp with moderate impact on transcription rate for saturated systems and rolling circle transcription products were evident with denaturizing PAGE gel electrophoresis for templates down to 167 bp. RNA polymerase RNAP T7 DNA nanotechnology molecular motor real time monitoring of transcription 2’ O methyl RNA molecular beacon minicircle Other bioengineering Övrig bioteknik
38	Process development for the production of a therapeutic Affibody® Molecule / Processutveckling för att tillverka en Affibody®-molekyl avsedd för cancerterapi Fridman, Belinda January 2014 (has links) Recently HER3, member of the epidermal growth factor receptor family (EGFR), has been found to play a crucial role in the development of resistance towards inhibitors that are given to patients with HER1- and HER2-driven cancers. As HER3 is up-regulated or over-activated in several types of human cancers, it is of outmost importance that new innovative drugs target its oncologic activity. The Affibody® Molecule Z08698 inhibits the heregulin induced signalling of HER3 with high affinity (KD~50 pM). As the Affibody® Molecule is small, has high solubility and outstanding folding kinetics, an effective penetration of tumour tissue is suggested together with a rationalized manufacturing process. Further coupling to an albumin binding domain (ABD) expands the plasma half-life of the molecule, hence increasing the molecule's potential of serving as a therapeutic. A process development for production of Z08698-VDGS-ABD094 has been established, where the molecule is efficiently produced in the E. coli host strain BL21(DE3), through a T7 based expression system. Cultivations were performed with a fed-batch fermentation process and the conditions were further optimized in order to obtain highest expression, while avoiding undesirable modifications like gluconoylations. By employing Design of experiments in combination with multivariate data analysis, a production process resulting in ~3.5 g product/ l culture could be verified. Moreover, thermolysis was evaluated as a suitable method for cell disruption, enabling an easy and cost-effective manufacturing process of the ABD fused Affibody® Molecule. Affibody® Molecule HER3 EGFR HER2 cancer therapy process development DOE multivariate data analysis E. coli ABD plasma half-life thermolysis fed-batch gluconoylation BL21(DE3) T7 expression system
39	The uncrowned queen : Alice Perrers, Edward III and political crisis in fourteenth-century England, 1360-1377 Tompkins, Laura January 2013 (has links) This thesis is a full political biography of Alice Perrers, the mistress of Edward III from the early 1360s until his death in June 1377 and mother to three of his children. It argues on the basis of the progression of her career that after the death of Edward's queen consort Philippa of Hainault in August 1369 Alice was able to extend the scope of her power and influence to the point that she became a ‘quasi' or ‘uncrowned' queen and, consequently, that her contribution to the political crisis of the 1370s can only be fully understood in terms of queenship. More generally, despite the recent increase on work on Alice, this study suggests that her life deserves a more thorough and nuanced appraisal than it has so far received. Various aspects of Alice's life are explored: her birth, family and first marriage; her early years as Edward III's mistress; the change in her status after Philippa of Hainault's death; her commercial activity as a moneylender and businesswoman; her accumulation of a landed estate and moveable goods; what happened to her in the Good Parliament; her trial in 1377; her marriage to William Wyndesore; and her life after Edward III's death. By examining Alice's career in this fashion it is shown that she took a leading role in the court party during the 1370s. Ultimately, by taking the original approach of applying ideas about queenship to a royal mistress this thesis demonstrates that Alice was perceived to have ‘inverted' or undermined the traditional role that the queen played in complementing and upholding the sovereignty and kingship of her husband, something that has implications for the wider study of not only mistresses, but also queens and queenship and even male favourites. 942.03
40	Stabil och antibiotikafri läkemedelsproduktion i rekombinant Escherichia coli Benevides, Kristina, Broström, Oscar, Elison Kalman, Grim, Swenson, Hugo, Vlassov, Andrei, Ågren, Josefin January 2017 (has links) Den här rapporten presenterar ett antibiotikafritt, stabilt och kromosombaserat expressionssystem för läkemedelsproduktion i Escherichia coli på beställning av företaget Affibody AB. E. coli-stammen BL21(DE3) valdes som värdorganism för expressionssystemet. Systemet består av en genkassett som innehåller en T7-promotor, en 5′-UTR från genen ompA och en terminatorsekvens från RNA-operonet rrnB. Fyra kopior av genkassetten ska integreras i pseudogenerna caiB, yjjM, hsdS och yjiV. En datormodell som modellerar det egentliga kopietalet i cellerna har skapats i mjukvaran MATLAB, vilket visar att det uppskattas vara maximalt 32 kopior av genkassetten per cell på grund av replikation av kromosomen. Ett högt pH i fermentorn; att använda fed-batch och blandade kolhydratkällor; och att använda stammen BL21(DE3) minskar acetatproduktionen i cellen. En lägre acetatproduktion kan leda till en högre produkthalt. En proteinutbytesmodell för mjukvaran MATLAB har konstruerats för att uppskatta koncentrationen av Affibody®-molekylen i en E. coli cell. copynumber copy-number copy number origin of replication rekombinant proteinexpression läkemedel E. coli antibiotikafri antibiotika expressionssystem expression system escherichia coli kromosom kromosombaserad kromosomal plasmidfri plasmid T7-promotor T7 promotor ompA rrnB autoinduktion auto induktion matlab kopietalmodell utbytemodell stabil pH pseudogen pseudo gen caiB yjjM hsdS yjiV fermentor batch fed-batch kontinuerlig fed batch fermentation Affibody affibody-molekyl affibody-molekyler affibodymolekyl affibodymolekyler bioreaktor acetat acetatbildning acetatproduktion acetatreduktion acetatreducering peptidläkemedel peptider peptid T7-system operator lac-operator operon 5'-UTR 3'-UTR sekundärstruktur mRNA T1 T2 terminator termineringssekvens optimering lac-operon repressor inducering BL21(DE3) BL21 B-stam B stam modell kopietal kopie tal OriC Pharmaceutical Biotechnology Läkemedelsbioteknik

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