Dr. Jennifer Lillig and group
The re-emergence of bacterial pathogens as a significant threat to public health has lead to an increased awarness of food safety. One of the most common food-borne pathogens is Listeria monocytogenes, a bacteria found to contaminate a variety of raw and processed foods including vegtables, meats, and dairy products. Listeria infection can result in a variety of illnesses ranging in severity from fever and nausea to meningitis and fetal miscarriage. In the past decade it has been found that lactic acid bacteria, common food borne bacteria that are non-pathogenic, produce small peptides termed bacteriocins, that kill Listeria. Work in our lab focuses on understanding the key features of these molecules that allow them to target and kill competing bacteria such as Listeria. This work can in turn aid in the further development of these molecules as both potent and safe drugs and food preservatives in the endevor to find new means of fighting and preventing human disease.
Characteristics of Protein Adsorption on Silica Surface
Dr. Meng-Chih Su and group
There is considerable interest in understanding and characterizing protein adsorption to substrate surfaces because of applications in biosensors, biomedical devices and other biotechnologies (protein chip technologies). Many of these protein chip technologies are based upon adsorbing or attaching a protein to a solid substrate. Therefore, the understanding of the fundamental principles governing the surface adsorption will improve our control of growing proteins on various substrates which is crucial to protein chip technologies. This is the main theme of our research. Denaturation effect on surface bound proteins is studied in this research group with use of prototype heme protein cytochrome c on fused silica surface. Using a high sensitivity optical technique, attenuated total reflection (ATR) polarization spectroscopy, it is now possible to characterize monolayer heme protein adsorption on the surface and hence focus on the protein-surface interactions. Thermodynamics and energy transfer involved in the surface adsorption are studied through adsorption equilibrium constants, surface packing density, and molecular orientation of protein coverage on the surface. Further chemical changes in the solution around the surface can cause denaturation to protein already on the surface, similar to the effect occurring in the biological system. Therefore, the conformational study of surface bound protein under these conditions is closely related to its native biological environment.
Inorganic and Bioinorganic Research
Dr. Carmen Works and group
My expertise and research interests lie in the area of reaction mechanisms involving transition metal chemistry and the importance of transition metal ions in biological systems. I have three projects that contribute to this subfield of inorganic chemistry. Two of these projects focus on the role of chromium ions in biological systems. The third project examines the photochemistry of a model for the active site of the iron-only hydrogenase, an enzyme involved in the oxidation of molecular hydrogen.
A) Chromium(III) binding proteins Chromium can exist in many different forms but the most stable and common are chromium (VI) and chromium (III) ions. Chromium (VI) is a particularly dangerous environmental pollutant due to its carcinogenicity and water solubility. Chromium (VI) is a strong oxidizing agent and inside biological systems participates in a string of complex redox reactions. Products of these reactions include chromium (III) DNA complexes, which are often discussed in the literature. My research at SSU has shown that chromium (III) can also form protein complexes after exposure to chromium(VI) . My working hypothesis is that these chromium (III) proteins are formed to prevent chromium (VI) from reacting with DNA, as a possible detoxification mechanism. In order to determine if these chromium (III) protein complexes serve a detoxification role, I have designed experiments to isolate and study the chromium (III) proteins that form in bovine liver after exposures to chromium (VI). In order to understand the function of these metallo-proteins, their structural information must first be determined, which is the long-term goal of my research in this area.
B) Chromate Reductase Bacteria can rapidly evolve to tolerate extreme chemical environments. This has become important in bioremediation of polluted soil and water. The chromate reductase project is concerned with studying the mechanisms that some bacteria utilize to live in high chromium (VI) environments. I am particularly interested in bacteria that can reduce toxic chromium (VI) to the less toxic chromium(III) form. This reduction process can only occur through a catalyzed reaction pathway, utilizing a type of enzyme called chromate reductase. My research group at SSU has identified a new bacteria, Pseudomonas Veronii that is capable of reducing chromium (VI), indicating the presence of a chromate reductase. We have performed a partial purification of the enzyme from Pseudomonas Veronii and the initial studies on the enzyme kinetics. The current goal for this project is the complete purification and structural characterization of Pseudomonas Veronii. The long-term goal for this project is to understand the functional role of this enzyme.
C) Photochemistry of m-(1,3-propanedithiolato)-hexacarbonyldiiron The focus of this project is the photochemical reactivity of m-(1,3-propanedithiolato)-hexacarbonyldiiron. This compound is a structural and functional model for the active site of iron-only hydrogenase. Iron-only hydrogenase is an enzyme that catalyzes the reversible oxidation of molecular hydrogen and is responsible for most of the bio-processing of hydrogen. The photochemical experiments in this project could lend insight into how bacteria use hydrogen as a fuel.
Organic, Polymer and Nanoparticle Research
Dr. Steve Farmer and group
My main area of research involves developing and utilizing ring contracting sulfur extrusion routes for the carbazole ring structure. An interesting use of these new desulfurization methods would be generating a general synthesis routes to natural products with the carbazole ring structure.
Another area of my research interests involves grafting polymer chains from the surface of organic crystals to form core/shell nanoparticles. These polymer encapsulated organic nanocrystals could provide new methods for drug delivery and film formation.
Dr. Mark Perri and group
Our group studies the impact of anthropogenic pollution on our local atmosphere. Our projects include measurements of: trace pollutants in our atmosphere by Gas Chromatography - Mass Spectrometery, aerosol optical thickness ("haze"), and ozone. These measurements are used along with computer modeling programs, to understand the types of processes that cause atmospheric pollution and to design control strategies for our unique local region.
Recently we have also been using ion chromatography to quantify pollutants in river water, in order to understand and limit our University's impact on our local watershed.
Dr. Monica Lares
The Lares lab is working on identifying key interactions between the B-cell-activating factor receptor (BAFF-R) protein and a RNA aptamer that specifically binds BAFF-R. BAFF-R is expressed on B-cells and overexpressed in non-Hodgkin's lymphoma. When BAFF-R's ligand, B-cell-activating factor (BAFF), binds, proliferation and cell survival increase allowing the cancer to spread faster. Aptamers are capable of binding their targets with high specificity and affinity and have recently been investigated for their therapeutic advantages over antibody-based approaches. An RNA aptamer has been identified that efficiently binds BAFF-R, thus preventing binding of its ligand. The RNA aptamer has also been used to deliver therapeutic reagents that kill the cell. We are working on identifying the specific amino acids of BAFF-R that are responsible for the binding of the aptamer using site-directed mutagenesis. We also want to identify the nucleotides of the RNA aptamer that specifically bind BAFF-R using RNase protection assays. Understanding the specific interactions between BAFF-R and its aptamer would allow us to increase specificity, reducing off-target effects, and facilitate this therapeutic approach through clinical trials.