Chemistry Department - SENIOR PROJECTS 2005-2006 (view abstracts below)
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Paul A. Kloek '06 |
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Development of Fluorescence Based Xenoandrogen Biosensor
Using the Hormone Binding Domain of the Human Androgen Receptor.
Jon French '06 with advisor Dr. Matt Skeels
A fluorescence based biosensor could be able to determine potential binding affinity of any given compound with the androgen receptor. The basis for this is that fluorescence is environment dependent, and specific amino acids, such as tryptophan, within the amino acid sequence of the protein receptor can be found in slightly different micro-environments. There is a large conformational change associated with the androgen receptor binding to a potential ligand. This change in receptor conformation changes the specific environment of the amino acids which make up the receptor. This environmental shift can be observed as a change in the fluorescence of the tryptophan residues within the receptor. the change in fluorescence between the bound and unbound protein can then be used to determine a binding curve which can be used to determine the relative binding affinity that the androgen receptor has for the specific ligand. This biosensor could potentially be used by the chemical or pharmaceutical industry to determine if a new compound poses the ability to bind to the androgen receptor.
Exploring Metallacrowns: Do Metallacrowns of First Row Transition Elements Fluoresce?
Paul A. Kloek with advisor Dr. Neil Law
Metallacrowns, similar to crown ethers in basic structure, are inorganic coordination compounds with very interesting properties. The size, general architecture and the presence of pi conjugated aromatic ring systems in the metallacrown molecule suggests a similiary to porphyrins, for example chlorophyll or heme. This raises the question as to whether metallacrowns might function in any capacity similiar to porphyrins. One property of porphyrins is their ability to fluoresce. Thus, the photophysical properties of metallacrowns are being tested during this project. To do this, metallacrowns consisting of copper, manganese, iron and nickel have been synthesized using the ligands naphthoylhydroxamic acid and salicylhydroxamic acid. Once synthesized, the complexes were analyzed to determine whether they are fluorescent. The Cu and Ni metallacrown exhibited fluorescence at lambda(max) values in the visible spectrum. In control experiments, the organic ligands utilized in this study were not observed to fluoresce or fluoresced less than the complexes. The Mn and Fe metallacrowns are now under further study.
Kristopher O'Connell with advisor Dr. Matt Skeels
The present investigation was carried for determination of mercury content in a Balaena mysticetus (bowhead whale) approximately 48 feet in length captured off of St. Lawrence Island off the coast of Alaska during the summer of 2005. Mercury overexposure can result in detrimental effect to the nervous system because of its lipophilicity, bio accumulation, and volatility (Krishna et al, 2005). Whale specimen was divided into two subgroups: skin and tissue. Evaluation of elemental mercury was done by cold vapor atomic absorption spectrometry (CVAAS). Results were compared with FDA approved levels to examine the risk factors of sonsumption. Mercury levels must be constantly monitored in order to prevent damage at the earliest possible stage.
Insolubility of T-Cell Receptors in Human Jurkat T-Cells
Jane Wambui Mutoru with advisor Dr. Nadia Marano
Previous research has shown that aggregating T-cell receptors (TCR) renders them difficult to solubilize using certain detergents. This sort of insolubility can mean interactions with specialized lipid micro domains, lipid rafts, which are important for sending signals to the interior of the cell, or to cytoskeletal structures. In our study, we aggregated different T-cell membrane components to test whether interactions between components affected insolubility of other components. Proteins were aggregated using primary antibodies followed by fluorescently-labeled secondary antibodies, while GM1 was aggregated using pentavalent cholera toxin B subunit. Preliminary results indicated insolubility ranges of between 70% and 80% for TCR and around 50% for GM1; M1 insolubility increased to around 80% when the TCR was also aggregated. However, the standard fluorescent labels resulted in low signal-to-noise ratio. Our current studies use the newly developed secondary antibodies conjugated to quantum dots, which are brighter and more stable fluorescent labels.