Theses and Dissertations from UMD
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New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a give thesis/dissertation in DRUM
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Item Simultaneous transcriptome profiling of Trypanosoma cruzi parasites and their human host cells.(2014) Li, Yuan; El-Sayed, Najib M; Cell Biology & Molecular Genetics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The genome of the kinetoplastid parasite Trypanosoma cruzi, causative agent of Chagas disease, was published nine years ago, yet a systematic and comprehensive analysis of the transcriptomes of the parasite and the human host has not been conducted. The parasite responds rapidly to transmission between arthropod vectors and mammalian hosts by undergoing complex cellular differentiation processes that are not well understood. In this study, we generated the first transcriptome map for both T. cruzi and infected human host cells across the infection cycle including time points of 4, 6, 12, 24, 48 and 72 hours post invasion with the next generation RNA sequencing technology (RNA-Seq). We also captured the transcriptome of the parasite in its bloodstream form (trypomastigote) and its replicative form inside insect vector (epimastigote). We successfully mapped transcribed regions for the pathogen at single nucleotide resolution on a genomic scale and characterized the RNA processing (trans-splicing and polyadenylation) events across its various developmental stages. Here we report the prevalent heterogeneity of RNA processing sites across the genome. We also note the preference of different primary sites in various developmental stages presenting as a potential and interesting approach of posttranscriptional regulation, which may hypothetically contribute to the survival of the parasite across different environments. Our work has significantly enhanced the current genome annotation of T. cruzi. In addition, using the T. cruzi and human genome sequence as reference, we explored these data with informatics tools to identify genes with significant regulation and successfully profiled gene expressions from both species simultaneously. We examined the subsets of differentially expressed genes both in the parasite and the host cell over the course of the infection to understand the mechanisms of invasion and intracellular survival strategy as well as host-pathogen interactions. T. cruzi genes that were significantly regulated during the infection process might present as new targets for drug development, whereas human genes that were significantly regulated might signal the immunoinflammatory response triggered by the manipulation of the parasite. Furthermore, we investigated the gene expression patterns of T. cruzi across its different developmental stages, clustered gene with similar patterns, and identified possible sequence motifs in coexpressed gene clusters.Item Prehistoric to Posthuman: Animality, Inheritance, and Identity in American Evolutionary Narratives(2010) Bailin, Deborah; Wyatt, David M; English Language and Literature; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This project examines how Darwinian discourse has influenced representations of the relationship between animality and humanness in twentieth-century American literature. Scholarship in the conceptually rich and growing field of animal studies, to which my dissertation contributes, covers a wide range of topics, from the symbolic and metaphoric treatment of nonhuman animals to the ethics of representation and the politics of animal rights. Recent theoretical work has further broadened the scope of inquiry by raising questions about the cultural construction of animality and its relationship to definitions of the human. Although some scholars have argued for the importance of embodiment in (re)considering twentieth-century representations of the human, challenging the opposition between "animal" and "human," only a few have addressed how Darwin's descriptions of prehuman ancestry and a potentially posthuman future might have shaped these representations. My study aims to rectify this critical lack. By examining how evolutionary narratives of growth, mutation, and transformation intersect with American narratives of history, progress, and identity, my dissertation complicates traditional associations between the cultural impact of Darwin's ideas and the determinism and social Darwinism often associated with literary naturalism during its classic phase. Beginning with a chapter comparing the treatment of animality and evolution in works by Frank Norris and Jack London, I trace the imaginative and metanaturalistic reshaping of these narratives across the century through chapters on abolition and evolution in novels by William Faulkner and Toni Morrison, evolution as apocalypse in Bernard Malamud's God's Grace and Octavia Butler's Xenogenesis Trilogy, and animals, evolution, and language in Edward Albee's plays. Varying in the scope of its concerns about natural and cultural inheritance, each of my chapters considers how animality operates as a recursive trope against the disembodiment of the subject, expressing both possibilities and fears about what it means to be human.