The Role of the Dorsomedial Hypothalamic Nucleus in Mediation of Seasonal Reproductive Rhythms in the Siberian Hamster

Morgan’s fascination with neurobiology led her to join the laboratory of Prof. Irving Zucker, where she has been studying the neuroendocrine basis of seasonal rhythms. Siberian hamsters, like most mammals, restrict production of offspring to the spring and summer. They do so by measuring day length. Neural and endocrine tissues decode day length by measuring the duration of nocturnal melatonin secretion. Morgan’s study, which will serve as the basis of her senior thesis, will assess whether the dorsomedial hypothalamic nucleus, a brain melatonin target tissue, is a necessary and sufficient component of the neural substrate that measures nightly melatonin duration and consequently day length. This project addresses a fundamental issue in regulatory biology and is of potential value in controlling and preserving animal populations.

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Sciences

How a DNA Repair Enzyme (DME) Controls Gene Transcription

The Arabidopsis thaliana genome has been sequenced, allowing use of sophisticated tools for genetic studies. It is known that DME controls gene transcription, encodes a DNA glycosylase, and has homologous proteins in the Arabidopsis genome as well as orthologs in rice, wheat, and maize. We do not know, however, how this is accomplished. Carolina will investigate the DEMETER protein, essential for seed viability in Arabidopsis, using molecular tools and genetics. The project has two phases: 1) To determine if the family member proteins can replace the DME protein; 2) determine what portions of the DME protein give it its unique ability to control gene transcription. The results of Carolina’s senior thesis in Plant and Microbial Biology may contribute to understanding the general biology of DNA repair and DNA transcription of major agricultural crops.

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Sciences

Effects of Environmental Atrazine Contamination on Rana Pipiens Gonadal Development

Atrazine is the most widely used herbicide in the U.S., with over 76 million pounds of the active ingredient applied annually. Recently, atrazine has been shown to cause endocrine disrupting effects in many vertebrates. When treated with atrazine in the lab, male Rana pipiens develop pseudohermaphrotidic testes which produce oocytes instead of sperm. This phenomenon has been characterized in frogs from areas of known atrazine contamination. However, there is no evidence directly linking atrazine to these gonadal abonormalities in the wild. In this area-specific study, I will raise field-collected frogs in atrazine-contaminated water from their natal lay site, as well as clean water obtained from this site on a different occasion. I will thus be able to elucidate the differential effect of environmental atrazine contamination in a controlled setting, bridging the gap between the field and the laboratory. This project will culminate in the writing of my senior honors thesis […]

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Sciences

How (And Should) Government Regulate Preimplantation Genetic Diagnosis?

The aim of Crystal’s project – the culmination of which will constitute her senior honors thesis in political science – is to discuss whether (and more importantly how) preimplantation genetic diagnosis (PGD) should be regulated. Crystal will be traveling to Washington, DC to address whether the objections behind PGD can be practically dealt with through various types of regulation. By attending meetings for the President’s Council on Bioethics and analyzing their most recent report, “Reproduction & Responsibility: The Regulation of New Biotechnologies,” Crystal will be assessing the effectiveness of using government advisory committees to address the ethical implications of PGD. Crystal will also be interviewing experts from various backgrounds and disciplines to ask for their thoughts on the interim recommendations presented in the Council’s latest report, as well as their thoughts on how to address PGD from a policy-making perspective.

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Sciences

V-Src Regulation of Protein Kinase C-Zeta

Activation of the proto-oncogene c-Src, a tyrosine kinase, is evident in major cancers such as breast and colon. C-Src activates substrates that serve important roles in controlling growth, survival and motility of cells. Activation of c-Src is known to cause transformation, the process by which normal cells become cancerous. David seeks to elucidate how v-Src, a viral constitutively active form of c-Src, regulates Protein Kinase Cz (PKCz), which is a protein involved in control of growth and survival. The Martin lab has shown that v-Src can tyrosine-phosphorylate PKCz and that it increases its nuclear localization and kinase activity. David seeks to (1) find possible PKCz nuclear substrates by co-immunoprecipitation followed by protein sequencing, and (2) look for up-regulation of the transcription factor responsive elements known to be regulated by v-Src using luciferase reporter assays on cells transfected with a nuclear-targeted form of PKCz. This work will culminate in an honors […]

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A Study of Selective Catalysis in Water

With costly Superfund cleanups making headlines recently, companies have realized that the most financially prudent solution to dispose of hazardous waste is not to produce it at all. In order to reach this goal, new heterogeneous catalysts will need to be developed that have high selectivity and activity in non-hazardous solvents. Andrews project will focus on the Knoevenagel condensation, a reaction important to industries from food additives to textiles. Generally, this reaction is performed in an organic solvent, many of which are carcinogenic. Andrews research will focus on the design and production of imprinted silica-based heterogeneous catalysts that will catalyze the reaction in water, the most environmentally benign solvent known. He will attempt to determine the role played by factors such as the degree of hydrophobicity of the local catalytic environment in making a good Knoevenagel catalyst in water. His project will contribute to the growing field of green chemistry.

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Sciences

Interferon-Dependent Innate Mechanisms in Mice with Dengue Infection

Dengue virus (DEN) causes the most widespread life-threatening arboviral disease in humans, with an estimated 2.5 billion people at risk worldwide. Despite the global morbidity and mortality, DEN specific vaccines and therapies currently do not exist, and both protective and pathogenic roles of the immune system in DEN infection need further investigation. The Harris laboratory has recently demonstrated that the interferon (IFN)-dependent immunity is essential and more important than T and B lymphocyte-dependent adaptive immunity in controlling primary DEN infection in mice. IFNs are proteins that are secreted by vertebrate cells. They act as intercellular mediators, and are best known for their ability to confer resistance to viral infections. Daniil will investigate how the IFN-dependent innate immune mechanisms resolve primary DEN infection in mice. Specifically, he will determine the major cellular sources of IFN-___ and IFN-___in T and B cell-deficient mice with primary DEN infection using a variety of immunologic […]

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Sciences

Identifying Hormonal Factors and Response Elements Regulating GPR82 mRNA Expression

The objective of Calvin’s study is to identify the hormonal factors and their regulatory mechanisms on GPR82 expression in the intestine. GPR82 is a recently identified orphan receptor whose ligand has not been found. Although little is now definitively known about this receptor, GPR82 may play important roles in the regulation of the GI tract. Its expression in peripheral tissues is the highest in the GI tract, and its mRNA level changes in response to the nutritional status in both a cell model and live rats. Calvin hypothesizes that GPR82 is transcriptionally regulated by hormonal factors responsive to nutritional status in the body. He will identify hormones that regulate GPR82 transcription, investigate the regulatory sites of target hormones by determining the response element in the promoter of GPR82, and determine the intracellular localization of GPR82. The proposed project will be part of Calvin’s senior honor thesis in Molecular and Cell […]

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Sciences

Subcellular Targeting of the p21-activated Protein Kinase, Cla4

The ability of cells to respond to extracellular signals is mediated by signal transduction networks that almost invariably include a cascade of protein kinases. One family of protein kinases that is universally conserved in eukaryotes is called the p21-activated protein kinases (PAKs). The genome of Saccharomyces cerevisiae has revealed a closely related PAK-type protein kinase called Cla4. Cla4 is required for the proper assembly of a novel cytoskeletal structure that is essential for cytokinesis thereby providing an important checkpoint in the highly regulated cell cycle. Lorraine will be investigating the specific roles of each of the known domains in Cla4 in order to fully understand when Cla4 gets localized to specific subcellular destinations, which domains are responsible for this targeting, and when Cla4 commences specific phosphorylation of critical subcellular substrates. By clarifying the role of Cla4 in the cell cycle checkpoint pathway, Lorraine’s studies may provide valuable information for the […]

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