In this work we delve into the theory of Chow-Heegner points, establishing some of their basic properties and developing two methods for their explicit computation. Chapters 1 and 2 cover the background material necessary for the later chapters. Chapter 3 gives several definitions of Chow-Heegner points and explores the specific setting of modular abelian varieties. Chapter 4 develops an algorithm for computing Chow-Heegner points via complex analytic methods, and Chapter 5 considers a corresponding algorithm in the p-adic setting.

This dissertation describes our efforts toward developing a unified synthesis of the kalininane family of antimalarial marine isocyanoterpenes. Chapter 1 focuses on the isolation, structure determination, subclass specification, biological activity, and proposed biogenesis of the kalihinanes. Additionally, methods for the synthesis of isonitriles and previous syntheses of kalihinanes and related isocyanoterpenes are described.

Chapter 2 describes our divergent synthetic plan, featuring an oxa Michael/Robinson annulation sequence and a Piers-type annulation for the rapid synthesis of the decalin framework of the kalihinanes. This strategy was validated with a formal synthesis of 10 isocyano 4 cadinene, and was subsequently applied toward the synthesis of kalihinanes bearing a pendant tetrahydropyran (kalihinol A) or tetrahydrofuran (kalihinol B). While the synthesis of the tetrahydropyran-containing kalihinanes has yet to be accomplished, our efforts toward tetrahydrofuran-containing kalihinanes culminated in the first synthesis of kalihinol B. An unexpected hydride shift has thwarted efforts to extend the synthesis to other tetrahydrofuran containing kalihinanes.

Chapter 3 focuses on the application of our strategy to the synthesis of unnatural kalihinane analogues. Several analogues have been prepared and subjected to an antiplasmodial assay. All of the synthetic isocyanoterpenes exhibited antiplasmodial activity against drug sensitive and drug-resistant strains of Plasmodium falciparum (IC50 < 1.2 µM). Furthermore, kalihinane-based small-molecule probes have been prepared, and will be used for protein profiling in P. falciparum.

Despite years of incremental progress in our understanding of diseases such as Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's Disease (HD), and amyotrophic lateral sclerosis (ALS), there are still no disease-modifying therapeutics. The discrepancy between the number of lead compounds and approved drugs may partially be a result of the methods used to generate the leads and highlights the need for new technology to obtain more detailed and physiologically relevant information on cellular processes in normal and diseased states. We developed a high-throughput automated microscope system and primary neuron model of HD that allows us to monitor dynamic stress responses in intact, fully differentiated neurons. We are able to assay thousands of conditions, including millions of neurons, in a short period of time, which can reveal completely new aspects of biology and identify lead therapeutics in the span of a few months when conventional methods could take years or fail all together. We use this system to understand how neurons, a long-lived, postmitotic cell type, differ in their acute responses to proteotoxic insults including those associated with malformed protein. We show that neurons have a deficient acute stress response to multiple known stimuli, including thermal stress, Hsp90 inhibition, and proteasome inhibition. We find that neurons have low expression of the two major stress-responsive transcriptional activators in mammals, HSF1 and HSF2. We also find that neurons have high constitutive chaperoning capability through relatively high levels of Hsp90 and Hsc70. High Hsp90, however, decreases the acute stress response through negative regulation of HSF1. By increasing HSF1 levels, we were able to restore the response in neurons and protect them from the toxicity associated with malformed protein. We propose a mechanism for the attenuated acute stress response in neurons that implicates a high Hsp90 to HSF1 ratio, which results in an increased ability to cope with chronic stresses, but decreased ability to respond acutely when basal homeostatic responses are overwhelmed. We conclude that targeted therapies to bolster acute stress responses in neurons through increasing HSF1 expression or activation will therefore benefit HD and other neurodegenerative disorders of protein conformation.

Aging is a complex biological process that affects organisms ranging from humans to yeast, and understanding this process holds great potential for reducing the impact of age-related diseases such as heart disease, cancer, and neurodegenerative diseases. In this dissertation I explore both how neurons regulate lifespan and how two genes fundamental to the aging process interact with each other. First, I explore the neuronal regulation of lifespan. While we know that altering neuronal function can alter lifespan, the specific mechanisms by which neurons affect these changes, especially at the level of neuronal communication, remain to be elucidated. I show that reduction in signaling of the C. elegans ASI gustatory neuron pair through chemical silencing with tetanus toxin extends lifespan, likely primarily through reducing secretion of a TGFβ ligand (DAF-7), inhibiting the insulin-like signaling pathway, and activating the transcription factor DAF-16. Further results, such as a partial independence from daf-16, hint at a neuronal regulation of lifespan more complex than a sensory dial which increases or reduces DAF-7 levels.

Second, I explore how the developmental arrest caused by reduction of activity of the fundamental lifespan gene heat shock factor 1 (hsf-1) can be rescued by loss of function of another gene, the ribosomal S6 kinase gene rsks-1. hsf-1, a regulator of the widely conserved heat-shock response, is not only essential for cellular stress resistance and adult longevity, but also for proper development. However, the genetic mechanisms by which heat-shock transcription factors regulate development are not well understood. I investigated how C. elegans strains derived from an unbiased genetic screen ameliorated the developmental-arrest phenotype of a heat-shock factor mutant. Here I show that loss of the conserved translational activator rsks-1/S6 Kinase, a downstream effector of mTOR kinase, can rescue the developmental-arrest phenotype of hsf-1 partial loss-of-function mutants. Unexpectedly, I show that the rescue is not likely caused by reduced translation, nor by activation of any of a variety of stress-protective genes and pathways. My findings identify an as-yet unexplained regulatory relationship between the heat-shock transcription factor and the mTOR pathway during C. elegans’ development.

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