ENZYME-FREE UBIQUITIN LIGATION. FROM NATIVE CHEMICAL LIGATION AND SPIN LABELING TO DIMERIZATION BY INTER-UBIQUITIN MIMICKING LINKAGE AND PH-DEPENDENT CONFORMATIONAL SWITCH

The delicate balance between the production and disposal of proteins is vital for the changes required in the cell to respond to given stimulus. Ubiquitination is a protein modification with a range of signaling outcomes when ubiquitin is attached to a protein through a highly ordered enzymatic cascade process. Understanding ubiquitination is a growing field and nowadays the application of chemical reactions allows the isolation of quantitative materials for structural studies. Therefore, in this dissertation it is described some of these suitable chemical methodologies to produce an isopeptide bond toward the polymerization of ubiquitin bypassing the enzymatic control with the purpose of showing if these chemical modifications have a direct impact on the structure of ubiquitin. First, the possibility of incorporating non-natural lysine analogs known as mercaptolysines into the polypeptide chain of Ubiquitin was explored when they were attached to ubiquitin by native chemical ligation at its C terminus. The sulfhydryl group was used for the attachment of a paramagnetic label to map the surface of ubiquitin. Second, the condensation catalyzed by silver nitrate was used for the dimer assembly. In particular, the main focus was on examining whether orthogonal protection and deprotection of each monomer have an impact on the reaction yield, since the synthetic strategy has been previously attempted successfully. Third, the formation of ubiquitin dimers was approached by building an inter-ubiquitin linkage mimicking the isopeptide bond with two approaches, the classic disulfide exchange as well as the thiol-ene click reaction by thermal initiation in aqueous conditions. After assembling the dimeric units, they were studied by Nuclear Magnetic Resonance, in order to establish a conformational state profile which depends on the pH conditions. The latter is a very important concept since some ligands have a preferred affinity when the protein-protein hydrophobic patches are in close proximity.

BOULANGER, SATIE, AND DEBUSSY: THEIR SPHERES OF INFLUENCE ON FRENCH MELODIE AND AMERICAN ART SONG

This dissertation project explored the spheres of influence on art song by Nadia Boulanger, Erik Satie, and Claude Debussy within Boulangeries, Les Six, and Les Apaches. After World War I, American composers flocked to Paris to study with Boulanger. Boulanger gave her students the confidence to explore their native talents instead of mimicking foreign models. Works by Aaron Copland, Virgil Thomson, Theodore Chanler, John Duke, and Richard Hundley were included in the first dissertation recital on January 31, 2010: The Legacy of Nadia Boulanger: Her Influence on American Song Composers. Satie established a new modern French musical style, and was a catalyst for the formation of Les Six. Ned Rorem came to Paris, and had a close association with Les Six. Works by Satie, and three members of Les Six, Francis Poulenc, Arthur Honegger, Darius Milhaud; and Rorem were featured in the second recital on September 1, 2010: Satie, Selected Members of Les Six, and Rorem in Paris. Debussy was one of the most significant French composers in the late nineteenth century, predating Boulanger and Satie. Young composers exploring new directions were inspired by Debussy, forming the group Les Apaches. The final recital, April 7, 2011, featured works by Debussy and two members of Les Apaches, Maurice Ravel and Manuel de Falla: Debussy: A Catalyst for Les Apaches, Ravel and Falla. Falla‘s less well-known repertoire was presented. This dissertation showed the influence of these three major figures and that they embraced innovation in their own time, along with their followers. Recordings of these three performances may be obtained from the Michelle Smith Performing Arts Library in Clarice Smith Performing Arts Center at the University of Maryland, College Park.

The Drama of History: Representation and Revolutionaries in Haitian Theater, 1818-1907

Since the beginning of the Haitian theatrical tradition there has been an ineluctable dedication to the representation of Haitian history on stage. Given the rich theatrical archive about Haiti throughout the world, this study considers operas and plays written solely by Haitian playwrights. By delving into the works of Juste Chanlatte, Massillon Coicou, and Vendenesse Ducasse this study proposes a re-reading of Haitian theater that considers the stage as an innovative site for contesting negative and clichéd representations of the Haitian Revolution and its revolutionary leadership. A genre long mired in accusations of mimicking European literary forms, this study proposes a reevaluation of Haitian theater and its literary origins.

Supplemental Coverage Option Expanding as Part of the Farm Safety Net

The 2014 Farm Bill created Supplemental Coverage Option (SCO), a new add-on crop insurance option which provides supplemental coverage on a producer’s underlying crop insurance policy. SCO operates by mimicking a producer’s individual crop insurance coverage and covering a portion of the deductible based on county-level yield or revenue. SCO is available in select Maryland counties for apples, barley, corn, grain sorghum, green peas, oats, peaches, processing beans, soybeans, sweet corn, and winter wheat, as of the 2017 crop year. USDA’s Risk Management Agency (RMA) continues to expand covered counties and crops covered, and begin distinguishing by practices (such as irrigated compared to non-irrigated).