京都大学 / 新制・課程博士 / 博士(農学) / 甲第23959号 / 農博第2508号 / 新制||農||1092(附属図書館) / 学位論文||R4||N5394(農学部図書室) / 京都大学大学院農学研究科応用生物科学専攻 / (主査)教授 益田 玲爾, 教授 三田村 啓理, 准教授 甲斐 嘉晃 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DGAM

Salmonella enterica sérovar Typhi est une bactérie à Gram négatif qui cause la maladie systémique nommée fièvre typhoïde. Cette maladie affecte environ 9 millions de personnes par année et se propage par la voie fécale-orale par ingestion d’aliments ou d’eau contaminés. Ainsi, la fièvre typhoïde est particulièrement problématique dans les pays ayant des systèmes d’assainissement peu efficaces. Elle peut être traitée par des antibiotiques, mais comme pour de nombreuses bactéries, la résistance est de plus en plus commune. À la suite d’une infection aiguë, environ 5% des patients deviennent porteurs chroniques asymptomatiques grâce à la formation de biofilms dans la vésicule biliaire et excrètent la bactérie dans leurs selles continuellement. Étant le seul réservoir connu de S. Typhi, cet état constitue une source importante de persistance et de propagation de la maladie. L’état de porteur est intraitable par antibiotiques en raison de la haute tolérance aux stress des biofilms et une chirurgie pour enlever la vésicule biliaire est souvent la solution la plus efficace. Il est connu que les biofilms de Salmonella contiennent principalement de la cellulose, des fimbriae curli, de l'acide colanique et des protéines BapA. Cependant, S. Typhi a accumulé de nombreux pseudogènes au cours de son évolution humain-spécifique, dont certains sont impliqués dans la biosynthèse de composants communs de biofilm chez Salmonella, comme la cellulose et l'acide colanique. Il est également proposé que l'expression de curli soit dysfonctionnelle chez S. Typhi. La production de biofilms chez cette souche n'a jamais été caractérisée dans des conditions in vitro optimisées. Par conséquent, nous supposons que les biofilms de S. Typhi soient uniques dans leur production et leur composition. Cette étude caractérise la composition et la structure d’un biofilm de S. Typhi in vitro. Nous déterminons qu’aucun composant de biofilm communément identifié chez Salmonella ne joue un rôle majeur dans les biofilms de S. Typhi. Nous identifions un rôle important pour l’ADN extracellulaire et l’intégrité des LPS. / Salmonella enterica serovar Typhi is a Gram-negative rod-shaped bacterium that causes the systemic disease of typhoid fever. This disease affects about 9 million people per year and is spread through the fecal-oral route by ingestion of contaminated food or water. Thus, typhoid fever is particularly problematic in countries with poor sanitation systems. It is currently treatable by antibiotics but as with many other bacteria, resistance is becoming more and more common. Following acute infection, ~5% of patients become chronic asymptomatic carriers through biofilm formation in the gallbladder and continuously shed the bacteria in their feces. Being the only known reservoir of S. Typhi, this is an important source of persistence of the disease in endemic areas and propagation to new areas. The carrier state is untreatable by antibiotics due to the high stress tolerance of biofilms. Gallbladder-removal surgery is often the most efficient solution. Salmonella biofilms are known to primarily contain cellulose, curli fimbriae, colanic acid and BapA proteins. However, S. Typhi evolved to be human-specific over time and has accumulated many pseudogenes in the process, some of which are genes in the biosynthetic pathways of biofilm-related components of Salmonella, such as cellulose and colanic acid. It is also proposed that curli expression is dysfunctional in S. Typhi. Biofilm production in this strain has never been characterized in optimized in vitro conditions. Therefore, we hypothesized that S. Typhi biofilms are unique in their production and composition. This study characterizes S. Typhi biofilm composition and structure in vitro. We determine that no biofilm components commonly identified in other bacteria play a major role in S. Typhi biofilms. We identify an important role for extracellular DNA and lipopolysaccharide-layer integrity.

Approved for public release, distribution is unlimited / Presently, the required data file to be loaded onto the Radar Warning Receiver (RWR) onboard the F-16 aircraft is done manually by the aircraft technicians, two to three hours prior to the actual flight time. This process should be automated. As such there is a need to look into the use of wireless transmission technology to complement or replace the manual method of loading the critical data file from the command station onto every F-16 aircraft. The present wireless technology is relatively mature and stable. In this thesis, the feasibility of incorporating and adapting this technology for use in the flight line environment is examined. The propagation effect in wireless transmission is also studied and recommendations proposed with regards to the installation of wireless facilities in the flight line. In addition, the EDNA, a portable maintenance aid that comes with the F-16 aircraft for loading the data file, has to be upgraded. Hence, a system feasibility study is carried out to adapt or upgrade the present equipment to wireless transmission capability. / Major, Republic of Singapore Air Force

This study devised a method to detect Ribeiroia ondatrae (class Trematoda) in water-bodies using environmental DNA (eDNA) collected from filtered water samples from selected ponds in the USA and Canada. Species-specific PCR primers were designed to target the Internal Transcribed Spacer-2 (ITS-2) region of the parasite’s genome. The qualitative PCR method was 70% (n=10) accurate in detecting R. ondatrae in ponds previously found to contain the parasite, while the qPCR method was 88.9% (n=9). To examine how the retinoic acid (RA) pathway gene expression may be perturbed during R. ondatrae infections, leading to limb development abnormalities in the wood frog (Lithobates sylvaticus). Multiple sequence alignments were used to design degenerate PCR primers to eight RA biosynthesis genes, but only two gene fragments were identified using this approach. Without effective primer sets it was not possible to measure changes in gene expression in infected frogs.

This study devised a method to detect Ribeiroia ondatrae (class Trematoda) in water-bodies using environmental DNA (eDNA) collected from filtered water samples from selected ponds in the USA and Canada. Species-specific PCR primers were designed to target the Internal Transcribed Spacer-2 (ITS-2) region of the parasite’s genome. The qualitative PCR method was 70% (n=10) accurate in detecting R. ondatrae in ponds previously found to contain the parasite, while the qPCR method was 88.9% (n=9). To examine how the retinoic acid (RA) pathway gene expression may be perturbed during R. ondatrae infections, leading to limb development abnormalities in the wood frog (Lithobates sylvaticus). Multiple sequence alignments were used to design degenerate PCR primers to eight RA biosynthesis genes, but only two gene fragments were identified using this approach. Without effective primer sets it was not possible to measure changes in gene expression in infected frogs.

The writing style of a number of authors writing in English was empirically investigated for the purpose of detecting stylistic patterns in relation to advancing age. The aim was to identify the type of stylistic markers among lexical, syntactical, phonemic, entropic, character-based, and content ones that would be most able to discriminate between early, middle, and late works of the selected authors, and the best classification or prediction algorithm most suited for this task. Two pilot studies were initially conducted. The first one concentrated on Christina Georgina Rossetti and Edgar Allan Poe from whom personal letters and poetry were selected as the genres of study, along with a limited selection of variables. Results suggested that authors and genre vary inconsistently. The second pilot study was based on Shakespeare's plays using a wider selection of variables to assess their discriminating power in relation to a past study. It was observed that the selected variables were of satisfactory predictive power, hence judged suitable for the task. Subsequently, four experiments were conducted using the variables tested in the second pilot study and personal correspondence and poetry from two additional authors, Edna St Vincent Millay and William Butler Yeats. Stepwise multiple linear regression and regression trees were selected to deal with the first two prediction experiments, and ordinal logistic regression and artificial neural networks for two classification experiments. The first experiment revealed inconsistency in accuracy of prediction and total number of variables in the final models affected by differences in authorship and genre. The second experiment revealed inconsistencies for the same factors in terms of accuracy only. The third experiment showed total number of variables in the model and error in the final model to be affected in various degrees by authorship, genre, different variable types and order in which the variables had been calculated. The last experiment had all measurements affected by the four factors. Examination of whether differences in method within each task play an important part revealed significant influences of method, authorship, and genre for the prediction problems, whereas all factors including method and various interactions dominated in the classification problems. Given the current data and methods used, as well as the results obtained, generalizable conclusions for the wider author population have been avoided.

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Recent research has revealed human settlement on the Pacific coast of Canada extending back nearly 14,000 years, but much of the late Pleistocene record is unknown due to shifting sea levels, poor understanding of Cordilleran ice extent, and limited research on the biota of the coast during this time. This study, undertaken in Quatsino First Nation and ‘Namgis First Nation territories as part of the Northern Vancouver Island Archaeology and Palaeoecology Project, employs modern multi-proxy analysis of lake sediment cores from two sites on northern Vancouver Island to reconstruct palaeoenvironments during and immediately following the Fraser Glaciation in coastal British Columbia. Evidence from radiocarbon samples, pollen, ancient environmental DNA, plant macrofossils, and diatoms indicates that Topknot Lake on the outer coast of Vancouver Island has remained unglaciated through most of the local Last Glacial Maximum since ca. 18,000 cal BP. A non-arboreal herb-shrub tundra assemblage prevailed from ca. 17,500-16,000 cal BP with taxa including willows (Salix), grasses, sedges (Cyperaceae), heathers (Ericaceae), and sagewort (Artemisia). After ca. 16,000 and into the terminal Pleistocene, Topknot Lake was dominated by pine, alder (Alnus), ferns, and aquatic plant species. In the Nimpkish River Valley deep in the Vancouver Island Ranges, Little Woss Lake also demonstrates a record extending to the late Pleistocene (ca. 14,300 cal BP). The environment comprised dry and cool conifer woodland dominated first by fir (Abies) until ca. 14,000 cal BP, then by pine, alder, and ferns from ca. 14,000-12,000 cal BP. eDNA evidence from ca. 14,000 cal BP corroborates these plant taxa as well as indicating brown bear and Chinook salmon in and around the basin at that time. A mixed-conifer assemblage consisting of pine, western hemlock, and alder followed from ca. 12,000-11,100 cal BP into the early Holocene. Collectively, these indicators demonstrate an open environment on the outer coast of northern Vancouver Island since ca. 18,000-17,500 cal BP and well-established biotic communities across the region throughout the late Pleistocene. These results inform future archaeological research for early human habitation in coastal British Columbia and provide key evidence to support the viability of the coastal migration route for the first peopling of the Americas. / Graduate / 2020-12-11

Edna O'Brien and Marian Keyes are two sexually candid female writers. They are both from Ireland and their novels have caused many spectacular headlines over the years. These female authors have been greatly acclaimed, but also sharply criticised for their outspoken way of writing. However they have enjoyed huge success and their novels have been read by many people. This essay will focus on two of the many novels written by these Irish authors: The Country Girls by Edna O'Brien and Anybody Out There? by Marian Keyes. In the following essay I will focus on Irish women represented in the novels of Keyes and O'Brien, and their relation to men but also to their daughters. In these novels, women are forced into strict gender roles, very different from those of men. Still, even though the older women in the novels are trapped in their roles, they encourage their daughters to develop and grow beyond such roles. I would argue that the novels and also the feminist actions that still occur in Ireland are built upon a long time of subordination for women, and also from the twisted structure in many of the Irish men-women-relationships. I would argue that the rules and roles created in historical Ireland, have formed an inequality between the sexes that still exists.

No description available.