http://hdl.handle.net/1813/39 http://ecommons.library.cornell.edu/retrieve/569 http://hdl.handle.net/1813/39 Search the Channel search http://ecommons.library.cornell.edu/simple-search http://hdl.handle.net/1813/11464 Title: Listeria monocytogenes pathogenesis: Part I: The role of flagella mediated motility Part II: The function of the metalloprotease propeptide <br/> <br/>Authors: O'Neil, Heather <br/> <br/>Abstract: Listeria monocytogenes is a food borne, intracellular bacterial pathogen. Successful infection requires completion of two steps: penetration of the intestinal epithelium and escape from the phagocytic vacuole. This dissertation examines the role of flagella mediated motility in host cell invasion, and the function of the metalloprotease (Mpl) propeptide in mediating the maturation of a bacterial phospholipase required for efficient escape from the phagocytic vacuole. We examined the contribution of flagella to L. monocytogenes pathogenesis. We observed that flagella mediated motility enhance the bacterial rate of invasion. To determine if flagella are adhesins, we performed adhesion and invasion assays with flagellated motile and non-motile bacteria, and non-flagellated bacteria. Flagellated but non-motile bacteria did not adhere to or invade human epithelial cells more efficiently than non-flagellated bacteria. These results indicate that flagella do not function as adhesins to host cells. Instead, motility is important for host cell invasion. Moreover, in vivo motile bacteria out competed non-motile bacteria in the colonization of the mouse intestines and liver at early time points after oral infection, suggesting that flagella-mediated motility enhances L. monocytogenes infectivity soon after bacterial ingestion. Mpl regulates the activity and compartmentalization of a bacterial phospholipase C (PC-PLC). Mpl is secreted as an inactive proprotein. In related proteases, the propeptide can serve as a folding catalyst (either in cis or in trans), influence protein compartmentalization, participate in intracellular trafficking, or decrease folding kinetics. We investigated the role of the Mpl propeptide by monitoring the behavior of Mpl synthesized in absence of its propeptide (Mpl?pro) and of two Mpl mutants with unstable propeptides. All three mutants mediated PC-PLC activation in vitro but were not functional in infected cells. This defect was not rescued by providing the propeptide in trans to the mpl?pro mutant. We also determined that PC-PLC co-purified with wild-type Mpl, Mpl?pro, and the Mpl propeptide indicating that the propeptide is not required for Mpl / PC-PLC interaction. However, the mutant Mpl species were aberrantly secreted in the cytosol of infected cells. These data indicate that the propeptide of Mpl maintains Mpl bacteria-associated, and that localization is essential to Mpl function during infection. http://hdl.handle.net/1813/11458 Title: TALKING ABOUT THE AESTHETIC OF THE HUMANE: EXPLORING COMMUNICATION IN THE CONTENT AND STRUCTURE OF HEINRICH B?LL?S EARLY NOVELS <br/> <br/>Authors: Low, David <br/> <br/>Abstract: In his Frankfurter Vorlesungen Heinrich B?ll attempts to formulate an aesthetic program that explains how the moral content of writing might be inscribed in its structure. This ?aesthetic of the humane? would involve the subject-matter and orientation of a work?s content toward the representation of the historically real and the truth content of that reality. The ?real? as it is in the historical world and that ?reality? that contains the truth content of the experienced world are to be unified in the aesthetic of the humane, and it is the author who is burdened with the task of mediating the two for her reader. In many of his essays B?ll privileges communication as an inherently moral act, and emphasizes the responsibility of the author to use his vocation humanely. In order to understand how B?ll realized the concept of the aesthetic of the humane in his own writing we may look to how he uses communication within his texts to demonstrate moral action. Communication between characters at the level of plot corresponds to the author?s obligation to depict the ?real? historical component, and communicative structures in the matrix of his novels relate to the ?reality? of mediated experience provided as commentary by the author to the reader. This thesis examines how B?ll delivers these dual messages using the depiction of communication in three of his early novels. B?ll?s early novels were chosen for analysis because they correspond to a period in his career before his writing entered into a direct dialogue with his detractors and political opponents. His later writing may be seen as responses to ?real? historical developments in his life, and as such do not exhibit the balance of the ?real? and ?reality? that are the goal of the engaged writer according to his own essays. Through a discussion of Und sagte kein einziges Wort, Billard um halb zehn, and Ansichten eines Clowns this thesis concludes that as of the moment that he articulates his aesthetic program in 1964 B?ll harbored doubts about its effectiveness to reach his audience and affect any meaningful change in society. http://hdl.handle.net/1813/11454 Title: HEALTHCARE STRATEGIC SUSTAINABILITY: KEY FACTORS AFFECTING THE TRIPLE BOTTOM LINE IN CONVERTING INPATIENT TO OUTPATIENT FACILITIES <br/> <br/>Authors: Zajac, David <br/> <br/>Abstract: Healthcare strategic sustainability seeks to integrate in a cost effective manner sustainable development and design practices with health care facilities that are holistic places of healing for patients; and a safe, efficient, and effective environment for staff. This study focused on six United States Army military healthcare facilities involving conversion from inpatient to outpatient facilities. Data was collected in an intensive interview process from twenty-nine participants representing three stakeholder categories: planners (design and construction), operators (facility management and information technology), and users (clinical staff). The specific research questions addressed what design/building changes were made to accommodate the change from an in-patient to an outpatient care business model; and which existing design/building elements generated significant constraints or benefits when implementing the desired new design concept? The research also explored whether any desired design/building changes were not made, and why; and the extent to which social (quality of care and/or quality of life), economic (cost), or environmental (adaptable and sustainable) factors were considered? The findings confirm the impact of certain design elements on the conversion and adaptability of hospitals; and suggest the need to educate organizations on which design elements to invest in that not only meet cost and environmental quality goals, but also contribute positively to staff quality of life. http://hdl.handle.net/1813/11424 Title: STUDIES OF CONFORMATIONAL CHANGES AND THE EFFECT OF ANTIBODY AND RECEPTOR BINDING ON CANINE PARVOVIRUS <br/> <br/>Authors: Nelson, Christian <br/> <br/>Abstract: To be successful pathogens, the capsid protein of nonenveloped viruses must balance two opposing roles: it must be structurally robust in order to protect the encapsulated genome from environmental insults outside of the host cell, yet metastable to allow egress of the viral genome upon infection. A goal of these studies was to further characterize the antibody response directed against canine parvovirus (CPV), and to understand the interplay between receptor and antibody binding to the capsid. A secondary goal was to understand what conformational changes occur to the structure of the CPV capsid during infection, and to understand the biological significance of these changes. A panel of eight antibodies directed against the virus were shown to be neutralizing as intact immunoglobulin G proteins (IgGs). However the fragment antigen binding domains (Fabs) of these IgGs differed greatly in their ability to neutralize CPV. These eight Fabs compete for receptor binding on the surface of cells, and compete with soluble receptor in solution, although neutralizing Fabs competed for binding at significantly lower Fab to capsid ratios. Structural analysis of those Fabs demonstrated that most accessible areas of the capsid are able to generate an immune response and participate in antibody binding. CPV is a highly stable virus, and harsh conditions do not cause large structural changes in the virus. By biochemical and biophysical assays presented here, the viral capsid is unchanged until pH 4 and is thermally stable to temperatures of 70?C. Conditions that the virus would encounter during infection, such as low pH and calcium removal, do not have direct structural effects on the CPV capsid. Furthermore, transferrin receptor or antibody binding does not cause detectable changes to the capsid structure. These studies show that CPV is an extremely robust pathogen, due to its highly stable capsid. The capsid has clearly evolved to persist in harsh environmental conditions outside of the cell, and infect in the presence of circulating antibodies.