BRCA1 is a gene found in humans that, when mutated, has been linked to breast and ovarian cancer. A homolog version of this gene, known as brc-1, exists in an organism called the Caenorhabditis elegans. This is a species of nematode worm that has the potential to be used as a model organism to study this homolog gene that is associated with human breast cancer. Previous studies with C. elegans have shown links between the brc-1 gene and DNA damage responses, cytochrome p450, or cyp, transcription levels, and ratios of male phenotype worms. This project focused on studying whether these brc-1 functions are dictated by the enzymatic activity of the protein made by this gene. To measure these phenotypes, we used a strain of C. elegans with a brc-1 mutation engineered to lack enzymatic activity of the BRCA1 protein toward nucleosomes. In order to determine how this lack of enzymatic activity affects brc-1 functions, we measured levels of reactive oxygen species (serving as a proxy for DNA damage), numbers of male offspring, and cyp levels in the mutant and wild-type C. elegans. Our initial results indicate the effects of enzymatic activity towards nucleosomes on the aforementioned phenotypes.

Our project focused on the conservation of activity of the protein BRD1 in C. elegans. C. elegans is a strong model organism for our study because BRD-1 is the worm ortholog to BARD1 in humans. Specifically, our focus is on its function as an enzyme to attach ubiquitin to the H2A tail of nucleosomes. We studied a structural mutation of BRD-1 that we predicted would interfere with its ability to bind its substrate, the nucleosome. We hypothesized that BRD-1 is bound to the nucleosome at this mutation site based on prior research in the human protein. Therefore, we integrated mutations found in humans into the DNA that codes for C. elegans BRD-1. A typical mutagenesis protocol was used to implement the mutations and then we expressed the proteins in E. coli cells. After that, nucleosomes were reconstituted by dialysis, and enzyme activity was assessed using a ubiquitination assay. These assays showed that BRD-1 in C. elegans does bind the nucleosome demonstrating conservation of the BARD1 function. Determining that function is conserved allowed us to determine that C. elegans is an appropriate organism to test mutations found in humans. This research has future clinical potential due to the ability to test mutations encountered in humans using a model organism and can aid with clinical treatment plans to help avoid the development of cancer.

Many anti-inflammatory drugs are currently in use to treat neuroinflammation in the brain which can result from Alzheimer's disease, Parkinson's disease, traumatic brain injury, and more. In collaboration with a company, P2Dbiosciences, we are testing drugs that can modulate the function of inflammatory cytokines such as TNF-alpha, with the goal of reducing neuroinflammation and thus benefiting people suffering from the neurodegeneration and cognitive decline associated with neuroinflammation. We hypothesize these drugs work by inhibiting the signaling associated with inflammatory cytokines.
Two different assays were developed to identify the mechanism of action of these cytokine modulating anti-inflammatory drugs. BV2 cells in culture were used for these assays to model how the drug affects mouse microglial cells (immune cells resident in the brain). The first assay uses a luciferase reporter gene to determine if NF-kB promoter activity is disrupted when cells are treated with drug. The second assay uses quantitative RT-PCR (qPCR) to measure changes in TNF-alpha mRNA levels when cells are treated with drug. Levels of TNF-alpha mRNA were also quantified over a period of time following drug treatment to determine whether the degradation time of the TNF-alpha mRNA was affected by treatment.

Invasive species, such as the Red Imported Fire Ant (Solenopsis invicta, hereafter, RIFA), can negatively impact native species via predation and modifying prey behavior. RIFA exist in two colony types, monogyne (single queen) and polygyne (multiple queens), and polygyne colonies are known to contain higher densities of fire ants than monogyne colonies. Texas horned lizard (Phrynosoma cornutum) eggs and hatchlings are suspected prey of RIFA’s foraging and aggressive behaviors. In this study, we collected fire ants from Karnes City and Kenedy to determine if Texas horned lizard density is lower around polygyne colonies. We collected and sequenced 30 ants, of which 20 were RIFA. Counter to our expectations, there seemed to be no correlation between RIFA colony type and Texas horned lizard density. Furthermore, we found evidence that monogyne and polgyne colonies were coexisting. In future studies, we think larger sampling sizes and determining ratios of polygyne to monogyne colonies within the same area would be useful for further testing the hypothesis that colony type may affect horned lizard density.

Emerging evidence suggests that the immune system is vulnerable to disruption in response to a wide variety of chemical contaminants; thus, there is a need to test chemicals for immunotoxicity. To understand how chemicals impact the ability of the immune system to ward off infection, a model system featuring fathead minnows (FHM, a common toxicological model) infected with Yersinia ruckeri (a bacteria) has been used. Using this model system, the impacts of chemicals on immune system function can be evaluated via pathogen resistance challenges, where a fish is infected with a pathogen and their ability to defend against the pathogen and survive infection is determined. However, the use of Y. ruckeri is unfavorable given that fish must be injected with Y. ruckeri to develop an infection, a process that is time consuming and inconsistent with natural routes of exposure. Thus, the goal of this project was to develop a new host-pathogen system for FHMs by identifying a pathogen that induces infection via immersion. To do this, the ability of three bacterial pathogens, Flavobacterium columnare, Aeromonas sobria and Aeromonas allosaccharophila, to infect FHMs via immersion was evaluated. Results of this study revealed that of the three bacterium evaluated, only F. columnare was capable of inducing an infection via immersion in FHMs and infection was only successful following a fin-clip procedure, in which a small portion of the caudal fin is removed. Overall, this result establishes the potential for a FHM-F. columnare model system for future use in immunotoxicity testing.