Jeffrey Allebach 

RAPD Genomic Analysis of Variation Within Populations of  Sea Oats (Uniola paniculata)

Advisor:  Dr. Steve Bush

The technique of random amplified polymorphic DNA (RAPD) involves amplifying DNA by the polymerase chain reaction while using single primers of arbitrary nucleotide sequence.  By using these arbitrary primers it is possible to determine the number of genetically different individuals within a natural population of sea oats (Uniola paniculata), a common dune grass found from Virginia to Texas.  By determining this number of different individuals, dune vegetation projects can be better designed to mimic natural populations.

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Katie Copenhaver

Advisor: Dr. Chris Hill

Saltmarsh Sharp-tailed Sparrows are almost unique among songbirds in that adults do not form pair bonds, females raise young alone, and males do not defend territories in the breeding season, instead travelling far and wide to seek mating opportunities with females. Working in the field and the lab, I participated in nearly all aspects of a study of Saltmarsh Sharp-tailed Sparrow mating systems. I extracted DNA from 200 mothers, chicks and males, amplified the DNA of several families of sparrows, and determined how many males were responsible for fathering the chicks in each nest.

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Jessica Nordin

Investigation Of The Mechanism Of  Cd8+ T Cell  Homeostasis After Activation By  C. Neoformans-Laden Microglial Cells

Advisor: Dr. Karen Aguirre

Immune function is relatively well understood in the periphery, but qualitative differences exist when infection occurs in the central nervous system (CNS), and these differences are poorly understood. One cell activated in response to CNS infection is the brain–resident macrophage, or microglial cell. Microglia interact with T lymphocytes, which bind to the MHC class I-peptide combination. Past research has focused on microglia/CD8+ T cell interaction in viral models. However, the pathogenic fungus Cryptococcus neoformans, and other non-viral facultative and obligate intracellular pathogens represent a considerable portion of reported CNS infections. Such pathogens do not interfere with host cell gene expression as do viral pathogens, and therefore must be controlled by different mechanisms. AICD is a homeostatic mechanism by which large clones of activated lymphocytes are removed from the system after infection has been cleared, leaving only a small population of memory cells. It is not known, and I plan to investigate, whether CD8+ T cell homeostasis is achieved through the AICD mechanism. Overall, an enhanced understanding of the mechanism of CD8+ T cells is significant as it is a rational basis for designing immunotherapy or vaccines based on CD8+ T cells.

Sherry Pittman  

Investigation of CD8+ T Cell Cytotoxicity on Central Nervous System Cells

Advisor: Dr. Karen Aguirre

CD8+ T lymphocytes are immune system cells that recognize and destroy other cells of the body that have become infected by viruses, in a process called cytotoxicity. This process occurs throughout the body, including the Central Nervous System. However, it is not known how CD8+  T cells help to clear non-viral microbes like bacteria and fungi from infected CNS cells. In cytotoxicity, CD8+ T cells lyse target cells that are displaying viral antigen on the surface of the infected cell.  Does the same cytotoxic process occur when CD8+ T cells encounter brain cells that have internalized bacteria or fungi?  To find out, we performed a Colorimetric Cytotoxicity Assay.  This assay determined whether cytotoxicity occurred by measuring the release of lactate dehydrogenase, LDH, upon cell lysis.  The antigen-presenting cells (EOC) and  CD8+ T cells (TK1)  were combined along with the Cryptococcus antigen.  When the LDH was released, a red product formed.  The degree of redness between the different setups was quantitatively measured with a spectrometer.  Significant red absorbance indicates a cytotoxic effect. After subtraction of color intensity in control wells (1 and 3), there was no significant increase in color intensity in the test wells (2). (Wells in rows 5 and 6 contain other assay controls.) This suggests that cytotoxicity did not between the fungi-laden antigen-presenting cells and T-lymphocytes. Therefore, CD8+ T cells must use some novel mechanism to destroy intracellular non-viral pathogens in the CNS.

Scott Tomko

Optimizing newly developed microsatellite DNA loci for paternity testing in saltmarsh sparrows

Advisor: Dr. Chris Hill

Microsatellites, present in all eukaryotes, are stretches of "junk" DNA that vary tremendously between individuals. Because of their variability, or polymorphism, they are useful for individual identification (as in forensic investigations) and for paternity determination. I used a three-primer PCR technique to determine which of 20 newly discovered microsatellite DNA loci amplified reliably. I then took the reliable loci and determined which showed the most polymorphism in a panel of 20 Saltmarsh Sharp-tailed Sparrows. I also tested the primers on Seaside Sparrows.

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