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The Diversity, Costs, And Benefits Of Shelters Built By Lepidopteran Caterpillars In A Costa Rican Dry Forest, Christina Baer

Dissertations

Thousands of Lepidoptera species build shelters as caterpillars using plant material and their own silk. Although these caterpillars and their shelters are recognized as playing important ecological roles, the structural diversity of shelters and the costs and benefits of different shelters to their builders are still poorly understood. In this dissertation, I use natural history observations, observational and manipulative field projects, and molecular and phylogenetic tools to investigate these questions for a diverse and abundant shelter-building caterpillar community within the dry forest of Palo Verde National Park, Costa Rica. In Chapter 1, I develop a system for categorizing and describing …

Achilles Is A Circadian Clock-Controlled Gene That Regulates The Immune System And Its Rhythmicity In Drosophila, Jiajia Li

Dissertations

Circadian clock is a transcriptional/translational feedback loop that drives the rhythmic expression of downstream mRNAs. Termed “clock-controlled genes,” these molecular outputs of the circadian clock orchestrate cellular, metabolic, and behavioral rhythms. As part of our on-going work to characterize key upstream regulators of circadian mRNA expression, we have identified a novel clock-controlled gene in Drosophila melanogaster, Achilles (Achl), which is rhythmic at the mRNA level in the brain and represses expression of immune response genes, especially anti-microbial peptides in the immune system. Achl knock-down in the brain dramatically elevates expression of crucial immune response genes, including IM1 …

Elucidating Mechanisms Of Protein Aggregation In Alzheimer’S Disease Using Antibody-Based Strategies., Benjamin A. Colvin

Dissertations

Alzheimer’s Disease (AD) is a devastating neurodegenerative disorder. There are two characteristic histopathological hallmarks in the brain: senile plaques and neurofibrillary tangles, composed of insoluble aggregates of the amyloids Amyloid-β (Aβ) and tau protein, respectively. These diagnostic markers, though distinctive, are not apparent effectors of AD pathology. Evidence has mounted suggesting smaller soluble aggregates (oligomers) of Aβ or tau are the true drivers of disease progression. This dissertation presents several amyloid biophysics projects. Aggregate biophysical parameters such as weight, shape, and conformation were measured using a range of methodologies, including Multiangle Light Scattering, Dynamic Light Scattering, UV-Circular Dichroism, UV-Fluorescence, Scanning …

Systematics, Biogeography, And Species Delimitation Of The Malagasy Psorospermum (Hypericaceae), Heritiana S. Ranarivelo

Dissertations

Psorospermum belongs to the tribe Vismieae (Hypericaceae). Morphologically, Psorospermum is very similar to Harungana, which also belongs to Vismieae along with another genus, Vismia. Interestingly, Harungana occurs in both Madagascar and mainland Africa, as does Psorospermum; Vismia occurs in both Africa and the New World. However, the phylogeny of the tribe and the relationship between the three genera are uncertain. Using freshly collected specimens from my fieldwork as well as extant herbarium specimens, I aimed first, to generate a phylogeny of Psorospermum; second, to investigate its biogeography; and third, to investigate species boundaries within Malagasy Psorospermum …

Dna-Binding And Cellular Uptake Properties Of Pyrrole-Imidazole Polyamides, Maria J. Scuderi

Dissertations

Pyrrole-imidazole polyamides (PAs) represent a class of synthetic ligands that bind to the minor groove of DNA through hydrogen bonds and can be programmed to recognize predetermined DNA sequences. Potential applications of these compounds include gene expression modulation, antimicrobial activity and cell imaging.

Studies conducted in our lab in collaboration with NanoVir have shown that large PAs exhibit antiviral activity against Human Papillomavirus (HPV), which is the most common sexually transmitted infectious agent in the US and the primary factor for the development of cervical cancer. PAs act against HPV by targeting the viral DNA and promoting its selective elimination …

Parasitism Of Free-Ranging Neotropical Primates: Examining Parasite-Host And Parasite-Parasite Relationships, Gideon A. Erkenswick

Dissertations

Parasites are infectious agents that require resources from host organisms to complete all or part of their lifecycles. It is customary for wild animals to acquire and maintain multiple parasitic infections during their lifetime. The effects of parasites on hosts vary across demographic and environmental variables, and in relation to each other. Moreover, the propensity for a host animal to acquire an infection can be influenced by other host species in the area that are susceptible to the same parasites. This dissertation describes and explores the natural parasite assemblage of a free-ranging community of nonhuman primates in the Peruvian Amazon …

Biophysical Studies Of Hairpin Polyamides With Broad-Spectrum Activity Against High-Risk Human Papillomaviruses, Carlos H. Castaneda

Dissertations

Human papillomavirus is a small dsDNA virus that infects mucosal and cutaneous epithelial tissues. Persistent infection with high-risk HPV is the main etiological agent in the development of cervical cancer worldwide. Although prophylactic vaccines against HPV are available, these preventative measures are type-specific and are ineffective against existing infections. Thus, there is a pressing need for antiviral drugs with a broad-spectrum activity against HPV to eradicate existing infections, no matter the subtype.

Our group and collaborators have synthesized an extensive library of novel N-methylpyrrole/N-methylimidazole (Py/Im) hairpin polyamides (PAs) with broad-spectrum activities against three prevalent oncogenic-HPV types (HPV16, …

In Vivo Characterization Of The Drosophila Mrna 3’-End Processing Core Cleavage Complex: Poly(A) Mrna & Histone Mrna 3’-End Processing, Daniel Michalski

Dissertations

A core cleavage complex (CCC) consisting of CPSF73, CPSF100 and Symplekin is required for co-transcriptional 3’ end processing of all metazoan pre-mRNAs, yet little is known about the in vivo molecular interactions within this complex. The CCC is a component of two distinct complexes, the cleavage/polyadenylation complex and the complex that processes non-polyadenylated histone pre-mRNAs. RNAi-depletion of CCC factors in Drosophila culture cells causes reduction of CCC processing activity on histone mRNAs, resulting in read through transcription. In contrast, RNAi-depletion of factors only required for histone mRNA processing allows use of downstream cryptic polyadenylation signals to produce polyadenylated histone mRNAs. …